| // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 
 | // Use of this source code is governed by a BSD-style license that can be | 
 | // found in the LICENSE file. | 
 |  | 
 | #include "net/third_party/quiche/src/quic/core/quic_framer.h" | 
 |  | 
 | #include <cstddef> | 
 | #include <cstdint> | 
 | #include <memory> | 
 | #include <string> | 
 | #include <utility> | 
 |  | 
 | #include "net/third_party/quiche/src/quic/core/crypto/crypto_framer.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/crypto_handshake.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/crypto_handshake_message.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/crypto_utils.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/null_decrypter.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/null_encrypter.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/quic_decrypter.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/quic_encrypter.h" | 
 | #include "net/third_party/quiche/src/quic/core/crypto/quic_random.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_connection_id.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_constants.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_data_reader.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_data_writer.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_error_codes.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_packets.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_socket_address_coder.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_stream_frame_data_producer.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_types.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_utils.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_versions.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_aligned.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_client_stats.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_fallthrough.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_map_util.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_stack_trace.h" | 
 | #include "net/third_party/quiche/src/common/platform/api/quiche_arraysize.h" | 
 | #include "net/third_party/quiche/src/common/platform/api/quiche_str_cat.h" | 
 | #include "net/third_party/quiche/src/common/platform/api/quiche_string_piece.h" | 
 | #include "net/third_party/quiche/src/common/platform/api/quiche_text_utils.h" | 
 |  | 
 | namespace quic { | 
 |  | 
 | namespace { | 
 |  | 
 | #define ENDPOINT \ | 
 |   (perspective_ == Perspective::IS_SERVER ? "Server: " : "Client: ") | 
 |  | 
 | // Number of bits the packet number length bits are shifted from the right | 
 | // edge of the header. | 
 | const uint8_t kPublicHeaderSequenceNumberShift = 4; | 
 |  | 
 | // There are two interpretations for the Frame Type byte in the QUIC protocol, | 
 | // resulting in two Frame Types: Special Frame Types and Regular Frame Types. | 
 | // | 
 | // Regular Frame Types use the Frame Type byte simply. Currently defined | 
 | // Regular Frame Types are: | 
 | // Padding            : 0b 00000000 (0x00) | 
 | // ResetStream        : 0b 00000001 (0x01) | 
 | // ConnectionClose    : 0b 00000010 (0x02) | 
 | // GoAway             : 0b 00000011 (0x03) | 
 | // WindowUpdate       : 0b 00000100 (0x04) | 
 | // Blocked            : 0b 00000101 (0x05) | 
 | // | 
 | // Special Frame Types encode both a Frame Type and corresponding flags | 
 | // all in the Frame Type byte. Currently defined Special Frame Types | 
 | // are: | 
 | // Stream             : 0b 1xxxxxxx | 
 | // Ack                : 0b 01xxxxxx | 
 | // | 
 | // Semantics of the flag bits above (the x bits) depends on the frame type. | 
 |  | 
 | // Masks to determine if the frame type is a special use | 
 | // and for specific special frame types. | 
 | const uint8_t kQuicFrameTypeBrokenMask = 0xE0;   // 0b 11100000 | 
 | const uint8_t kQuicFrameTypeSpecialMask = 0xC0;  // 0b 11000000 | 
 | const uint8_t kQuicFrameTypeStreamMask = 0x80; | 
 | const uint8_t kQuicFrameTypeAckMask = 0x40; | 
 | static_assert(kQuicFrameTypeSpecialMask == | 
 |                   (kQuicFrameTypeStreamMask | kQuicFrameTypeAckMask), | 
 |               "Invalid kQuicFrameTypeSpecialMask"); | 
 |  | 
 | // The stream type format is 1FDOOOSS, where | 
 | //    F is the fin bit. | 
 | //    D is the data length bit (0 or 2 bytes). | 
 | //    OO/OOO are the size of the offset. | 
 | //    SS is the size of the stream ID. | 
 | // Note that the stream encoding can not be determined by inspection. It can | 
 | // be determined only by knowing the QUIC Version. | 
 | // Stream frame relative shifts and masks for interpreting the stream flags. | 
 | // StreamID may be 1, 2, 3, or 4 bytes. | 
 | const uint8_t kQuicStreamIdShift = 2; | 
 | const uint8_t kQuicStreamIDLengthMask = 0x03; | 
 |  | 
 | // Offset may be 0, 2, 4, or 8 bytes. | 
 | const uint8_t kQuicStreamShift = 3; | 
 | const uint8_t kQuicStreamOffsetMask = 0x07; | 
 |  | 
 | // Data length may be 0 or 2 bytes. | 
 | const uint8_t kQuicStreamDataLengthShift = 1; | 
 | const uint8_t kQuicStreamDataLengthMask = 0x01; | 
 |  | 
 | // Fin bit may be set or not. | 
 | const uint8_t kQuicStreamFinShift = 1; | 
 | const uint8_t kQuicStreamFinMask = 0x01; | 
 |  | 
 | // The format is 01M0LLOO, where | 
 | //   M if set, there are multiple ack blocks in the frame. | 
 | //  LL is the size of the largest ack field. | 
 | //  OO is the size of the ack blocks offset field. | 
 | // packet number size shift used in AckFrames. | 
 | const uint8_t kQuicSequenceNumberLengthNumBits = 2; | 
 | const uint8_t kActBlockLengthOffset = 0; | 
 | const uint8_t kLargestAckedOffset = 2; | 
 |  | 
 | // Acks may have only one ack block. | 
 | const uint8_t kQuicHasMultipleAckBlocksOffset = 5; | 
 |  | 
 | // Timestamps are 4 bytes followed by 2 bytes. | 
 | const uint8_t kQuicNumTimestampsLength = 1; | 
 | const uint8_t kQuicFirstTimestampLength = 4; | 
 | const uint8_t kQuicTimestampLength = 2; | 
 | // Gaps between packet numbers are 1 byte. | 
 | const uint8_t kQuicTimestampPacketNumberGapLength = 1; | 
 |  | 
 | // Maximum length of encoded error strings. | 
 | const int kMaxErrorStringLength = 256; | 
 |  | 
 | const uint8_t kConnectionIdLengthAdjustment = 3; | 
 | const uint8_t kDestinationConnectionIdLengthMask = 0xF0; | 
 | const uint8_t kSourceConnectionIdLengthMask = 0x0F; | 
 |  | 
 | // Returns the absolute value of the difference between |a| and |b|. | 
 | uint64_t Delta(uint64_t a, uint64_t b) { | 
 |   // Since these are unsigned numbers, we can't just return abs(a - b) | 
 |   if (a < b) { | 
 |     return b - a; | 
 |   } | 
 |   return a - b; | 
 | } | 
 |  | 
 | uint64_t ClosestTo(uint64_t target, uint64_t a, uint64_t b) { | 
 |   return (Delta(target, a) < Delta(target, b)) ? a : b; | 
 | } | 
 |  | 
 | QuicPacketNumberLength ReadSequenceNumberLength(uint8_t flags) { | 
 |   switch (flags & PACKET_FLAGS_8BYTE_PACKET) { | 
 |     case PACKET_FLAGS_8BYTE_PACKET: | 
 |       return PACKET_6BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_4BYTE_PACKET: | 
 |       return PACKET_4BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_2BYTE_PACKET: | 
 |       return PACKET_2BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_1BYTE_PACKET: | 
 |       return PACKET_1BYTE_PACKET_NUMBER; | 
 |     default: | 
 |       QUIC_BUG << "Unreachable case statement."; | 
 |       return PACKET_6BYTE_PACKET_NUMBER; | 
 |   } | 
 | } | 
 |  | 
 | QuicPacketNumberLength ReadAckPacketNumberLength( | 
 |     uint8_t flags) { | 
 |   switch (flags & PACKET_FLAGS_8BYTE_PACKET) { | 
 |     case PACKET_FLAGS_8BYTE_PACKET: | 
 |       return PACKET_6BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_4BYTE_PACKET: | 
 |       return PACKET_4BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_2BYTE_PACKET: | 
 |       return PACKET_2BYTE_PACKET_NUMBER; | 
 |     case PACKET_FLAGS_1BYTE_PACKET: | 
 |       return PACKET_1BYTE_PACKET_NUMBER; | 
 |     default: | 
 |       QUIC_BUG << "Unreachable case statement."; | 
 |       return PACKET_6BYTE_PACKET_NUMBER; | 
 |   } | 
 | } | 
 |  | 
 | uint8_t PacketNumberLengthToOnWireValue( | 
 |     QuicPacketNumberLength packet_number_length) { | 
 |   return packet_number_length - 1; | 
 | } | 
 |  | 
 | QuicPacketNumberLength GetShortHeaderPacketNumberLength(uint8_t type) { | 
 |   DCHECK(!(type & FLAGS_LONG_HEADER)); | 
 |   return static_cast<QuicPacketNumberLength>((type & 0x03) + 1); | 
 | } | 
 |  | 
 | uint8_t LongHeaderTypeToOnWireValue(QuicLongHeaderType type) { | 
 |   switch (type) { | 
 |     case INITIAL: | 
 |       return 0; | 
 |     case ZERO_RTT_PROTECTED: | 
 |       return 1 << 4; | 
 |     case HANDSHAKE: | 
 |       return 2 << 4; | 
 |     case RETRY: | 
 |       return 3 << 4; | 
 |     case VERSION_NEGOTIATION: | 
 |       return 0xF0;  // Value does not matter | 
 |     default: | 
 |       QUIC_BUG << "Invalid long header type: " << type; | 
 |       return 0xFF; | 
 |   } | 
 | } | 
 |  | 
 | bool GetLongHeaderType(uint8_t type, QuicLongHeaderType* long_header_type) { | 
 |   DCHECK((type & FLAGS_LONG_HEADER)); | 
 |   switch ((type & 0x30) >> 4) { | 
 |     case 0: | 
 |       *long_header_type = INITIAL; | 
 |       break; | 
 |     case 1: | 
 |       *long_header_type = ZERO_RTT_PROTECTED; | 
 |       break; | 
 |     case 2: | 
 |       *long_header_type = HANDSHAKE; | 
 |       break; | 
 |     case 3: | 
 |       *long_header_type = RETRY; | 
 |       break; | 
 |     default: | 
 |       QUIC_BUG << "Unreachable statement"; | 
 |       *long_header_type = INVALID_PACKET_TYPE; | 
 |       return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | QuicPacketNumberLength GetLongHeaderPacketNumberLength(uint8_t type) { | 
 |   return static_cast<QuicPacketNumberLength>((type & 0x03) + 1); | 
 | } | 
 |  | 
 | // Used to get packet number space before packet gets decrypted. | 
 | PacketNumberSpace GetPacketNumberSpace(const QuicPacketHeader& header) { | 
 |   switch (header.form) { | 
 |     case GOOGLE_QUIC_PACKET: | 
 |       QUIC_BUG << "Try to get packet number space of Google QUIC packet"; | 
 |       break; | 
 |     case IETF_QUIC_SHORT_HEADER_PACKET: | 
 |       return APPLICATION_DATA; | 
 |     case IETF_QUIC_LONG_HEADER_PACKET: | 
 |       switch (header.long_packet_type) { | 
 |         case INITIAL: | 
 |           return INITIAL_DATA; | 
 |         case HANDSHAKE: | 
 |           return HANDSHAKE_DATA; | 
 |         case ZERO_RTT_PROTECTED: | 
 |           return APPLICATION_DATA; | 
 |         case VERSION_NEGOTIATION: | 
 |         case RETRY: | 
 |         case INVALID_PACKET_TYPE: | 
 |           QUIC_BUG << "Try to get packet number space of long header type: " | 
 |                    << QuicUtils::QuicLongHeaderTypetoString( | 
 |                           header.long_packet_type); | 
 |           break; | 
 |       } | 
 |   } | 
 |  | 
 |   return NUM_PACKET_NUMBER_SPACES; | 
 | } | 
 |  | 
 | EncryptionLevel GetEncryptionLevel(const QuicPacketHeader& header) { | 
 |   switch (header.form) { | 
 |     case GOOGLE_QUIC_PACKET: | 
 |       QUIC_BUG << "Cannot determine EncryptionLevel from Google QUIC header"; | 
 |       break; | 
 |     case IETF_QUIC_SHORT_HEADER_PACKET: | 
 |       return ENCRYPTION_FORWARD_SECURE; | 
 |     case IETF_QUIC_LONG_HEADER_PACKET: | 
 |       switch (header.long_packet_type) { | 
 |         case INITIAL: | 
 |           return ENCRYPTION_INITIAL; | 
 |         case HANDSHAKE: | 
 |           return ENCRYPTION_HANDSHAKE; | 
 |         case ZERO_RTT_PROTECTED: | 
 |           return ENCRYPTION_ZERO_RTT; | 
 |         case VERSION_NEGOTIATION: | 
 |         case RETRY: | 
 |         case INVALID_PACKET_TYPE: | 
 |           QUIC_BUG << "No encryption used with type " | 
 |                    << QuicUtils::QuicLongHeaderTypetoString( | 
 |                           header.long_packet_type); | 
 |       } | 
 |   } | 
 |   return NUM_ENCRYPTION_LEVELS; | 
 | } | 
 |  | 
 | quiche::QuicheStringPiece TruncateErrorString(quiche::QuicheStringPiece error) { | 
 |   if (error.length() <= kMaxErrorStringLength) { | 
 |     return error; | 
 |   } | 
 |   return quiche::QuicheStringPiece(error.data(), kMaxErrorStringLength); | 
 | } | 
 |  | 
 | size_t TruncatedErrorStringSize(const quiche::QuicheStringPiece& error) { | 
 |   if (error.length() < kMaxErrorStringLength) { | 
 |     return error.length(); | 
 |   } | 
 |   return kMaxErrorStringLength; | 
 | } | 
 |  | 
 | uint8_t GetConnectionIdLengthValue(QuicConnectionIdLength length) { | 
 |   if (length == 0) { | 
 |     return 0; | 
 |   } | 
 |   return static_cast<uint8_t>(length - kConnectionIdLengthAdjustment); | 
 | } | 
 |  | 
 | bool IsValidPacketNumberLength(QuicPacketNumberLength packet_number_length) { | 
 |   size_t length = packet_number_length; | 
 |   return length == 1 || length == 2 || length == 4 || length == 6 || | 
 |          length == 8; | 
 | } | 
 |  | 
 | bool IsValidFullPacketNumber(uint64_t full_packet_number, | 
 |                              ParsedQuicVersion version) { | 
 |   return full_packet_number > 0 || version.HasIetfQuicFrames(); | 
 | } | 
 |  | 
 | bool AppendIetfConnectionIds(bool version_flag, | 
 |                              bool use_length_prefix, | 
 |                              QuicConnectionId destination_connection_id, | 
 |                              QuicConnectionId source_connection_id, | 
 |                              QuicDataWriter* writer) { | 
 |   if (!version_flag) { | 
 |     return writer->WriteConnectionId(destination_connection_id); | 
 |   } | 
 |  | 
 |   if (use_length_prefix) { | 
 |     return writer->WriteLengthPrefixedConnectionId(destination_connection_id) && | 
 |            writer->WriteLengthPrefixedConnectionId(source_connection_id); | 
 |   } | 
 |  | 
 |   // Compute connection ID length byte. | 
 |   uint8_t dcil = GetConnectionIdLengthValue( | 
 |       static_cast<QuicConnectionIdLength>(destination_connection_id.length())); | 
 |   uint8_t scil = GetConnectionIdLengthValue( | 
 |       static_cast<QuicConnectionIdLength>(source_connection_id.length())); | 
 |   uint8_t connection_id_length = dcil << 4 | scil; | 
 |  | 
 |   return writer->WriteUInt8(connection_id_length) && | 
 |          writer->WriteConnectionId(destination_connection_id) && | 
 |          writer->WriteConnectionId(source_connection_id); | 
 | } | 
 |  | 
 | enum class DroppedPacketReason { | 
 |   // General errors | 
 |   INVALID_PUBLIC_HEADER, | 
 |   VERSION_MISMATCH, | 
 |   // Version negotiation packet errors | 
 |   INVALID_VERSION_NEGOTIATION_PACKET, | 
 |   // Public reset packet errors, pre-v44 | 
 |   INVALID_PUBLIC_RESET_PACKET, | 
 |   // Data packet errors | 
 |   INVALID_PACKET_NUMBER, | 
 |   INVALID_DIVERSIFICATION_NONCE, | 
 |   DECRYPTION_FAILURE, | 
 |   NUM_REASONS, | 
 | }; | 
 |  | 
 | void RecordDroppedPacketReason(DroppedPacketReason reason) { | 
 |   QUIC_CLIENT_HISTOGRAM_ENUM("QuicDroppedPacketReason", reason, | 
 |                              DroppedPacketReason::NUM_REASONS, | 
 |                              "The reason a packet was not processed. Recorded " | 
 |                              "each time such a packet is dropped"); | 
 | } | 
 |  | 
 | PacketHeaderFormat GetIetfPacketHeaderFormat(uint8_t type_byte) { | 
 |   return type_byte & FLAGS_LONG_HEADER ? IETF_QUIC_LONG_HEADER_PACKET | 
 |                                        : IETF_QUIC_SHORT_HEADER_PACKET; | 
 | } | 
 |  | 
 | std::string GenerateErrorString(std::string initial_error_string, | 
 |                                 QuicErrorCode quic_error_code) { | 
 |   if (quic_error_code == QUIC_IETF_GQUIC_ERROR_MISSING) { | 
 |     // QUIC_IETF_GQUIC_ERROR_MISSING is special -- it means not to encode | 
 |     // the error value in the string. | 
 |     return initial_error_string; | 
 |   } | 
 |   return quiche::QuicheStrCat( | 
 |       std::to_string(static_cast<unsigned>(quic_error_code)), ":", | 
 |       initial_error_string); | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | QuicFramer::QuicFramer(const ParsedQuicVersionVector& supported_versions, | 
 |                        QuicTime creation_time, | 
 |                        Perspective perspective, | 
 |                        uint8_t expected_server_connection_id_length) | 
 |     : visitor_(nullptr), | 
 |       error_(QUIC_NO_ERROR), | 
 |       last_serialized_server_connection_id_(EmptyQuicConnectionId()), | 
 |       last_serialized_client_connection_id_(EmptyQuicConnectionId()), | 
 |       version_(PROTOCOL_UNSUPPORTED, QUIC_VERSION_UNSUPPORTED), | 
 |       supported_versions_(supported_versions), | 
 |       decrypter_level_(ENCRYPTION_INITIAL), | 
 |       alternative_decrypter_level_(NUM_ENCRYPTION_LEVELS), | 
 |       alternative_decrypter_latch_(false), | 
 |       perspective_(perspective), | 
 |       validate_flags_(true), | 
 |       process_timestamps_(false), | 
 |       creation_time_(creation_time), | 
 |       last_timestamp_(QuicTime::Delta::Zero()), | 
 |       first_sending_packet_number_(FirstSendingPacketNumber()), | 
 |       data_producer_(nullptr), | 
 |       infer_packet_header_type_from_version_(perspective == | 
 |                                              Perspective::IS_CLIENT), | 
 |       expected_server_connection_id_length_( | 
 |           expected_server_connection_id_length), | 
 |       expected_client_connection_id_length_(0), | 
 |       supports_multiple_packet_number_spaces_(false), | 
 |       last_written_packet_number_length_(0), | 
 |       peer_ack_delay_exponent_(kDefaultAckDelayExponent), | 
 |       local_ack_delay_exponent_(kDefaultAckDelayExponent), | 
 |       current_received_frame_type_(0) { | 
 |   DCHECK(!supported_versions.empty()); | 
 |   version_ = supported_versions_[0]; | 
 |   DCHECK(version_.IsKnown()) | 
 |       << ParsedQuicVersionVectorToString(supported_versions_); | 
 | } | 
 |  | 
 | QuicFramer::~QuicFramer() {} | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMinStreamFrameSize(QuicTransportVersion version, | 
 |                                          QuicStreamId stream_id, | 
 |                                          QuicStreamOffset offset, | 
 |                                          bool last_frame_in_packet, | 
 |                                          size_t data_length) { | 
 |   if (VersionHasIetfQuicFrames(version)) { | 
 |     return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(stream_id) + | 
 |            (last_frame_in_packet | 
 |                 ? 0 | 
 |                 : QuicDataWriter::GetVarInt62Len(data_length)) + | 
 |            (offset != 0 ? QuicDataWriter::GetVarInt62Len(offset) : 0); | 
 |   } | 
 |   return kQuicFrameTypeSize + GetStreamIdSize(stream_id) + | 
 |          GetStreamOffsetSize(offset) + | 
 |          (last_frame_in_packet ? 0 : kQuicStreamPayloadLengthSize); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMinCryptoFrameSize(QuicStreamOffset offset, | 
 |                                          QuicPacketLength data_length) { | 
 |   return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(offset) + | 
 |          QuicDataWriter::GetVarInt62Len(data_length); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMessageFrameSize(QuicTransportVersion version, | 
 |                                        bool last_frame_in_packet, | 
 |                                        QuicByteCount length) { | 
 |   QUIC_BUG_IF(!VersionSupportsMessageFrames(version)) | 
 |       << "Try to serialize MESSAGE frame in " << version; | 
 |   return kQuicFrameTypeSize + | 
 |          (last_frame_in_packet ? 0 : QuicDataWriter::GetVarInt62Len(length)) + | 
 |          length; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMinAckFrameSize(QuicTransportVersion version, | 
 |                                       const QuicAckFrame& ack_frame, | 
 |                                       uint32_t local_ack_delay_exponent) { | 
 |   if (VersionHasIetfQuicFrames(version)) { | 
 |     // The minimal ack frame consists of the following fields: Largest | 
 |     // Acknowledged, ACK Delay, 0 ACK Block Count, First ACK Block and ECN | 
 |     // counts. | 
 |     // Type byte + largest acked. | 
 |     size_t min_size = | 
 |         kQuicFrameTypeSize + | 
 |         QuicDataWriter::GetVarInt62Len(LargestAcked(ack_frame).ToUint64()); | 
 |     // Ack delay. | 
 |     min_size += QuicDataWriter::GetVarInt62Len( | 
 |         ack_frame.ack_delay_time.ToMicroseconds() >> local_ack_delay_exponent); | 
 |     // 0 ack block count. | 
 |     min_size += QuicDataWriter::GetVarInt62Len(0); | 
 |     // First ack block. | 
 |     min_size += QuicDataWriter::GetVarInt62Len( | 
 |         ack_frame.packets.Empty() ? 0 | 
 |                                   : ack_frame.packets.rbegin()->Length() - 1); | 
 |     // ECN counts. | 
 |     if (ack_frame.ecn_counters_populated && | 
 |         (ack_frame.ect_0_count || ack_frame.ect_1_count || | 
 |          ack_frame.ecn_ce_count)) { | 
 |       min_size += (QuicDataWriter::GetVarInt62Len(ack_frame.ect_0_count) + | 
 |                    QuicDataWriter::GetVarInt62Len(ack_frame.ect_1_count) + | 
 |                    QuicDataWriter::GetVarInt62Len(ack_frame.ecn_ce_count)); | 
 |     } | 
 |     return min_size; | 
 |   } | 
 |   return kQuicFrameTypeSize + | 
 |          GetMinPacketNumberLength(LargestAcked(ack_frame)) + | 
 |          kQuicDeltaTimeLargestObservedSize + kQuicNumTimestampsSize; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetStopWaitingFrameSize( | 
 |     QuicPacketNumberLength packet_number_length) { | 
 |   size_t min_size = kQuicFrameTypeSize + packet_number_length; | 
 |   return min_size; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetRstStreamFrameSize(QuicTransportVersion version, | 
 |                                          const QuicRstStreamFrame& frame) { | 
 |   if (VersionHasIetfQuicFrames(version)) { | 
 |     return QuicDataWriter::GetVarInt62Len(frame.stream_id) + | 
 |            QuicDataWriter::GetVarInt62Len(frame.byte_offset) + | 
 |            kQuicFrameTypeSize + | 
 |            QuicDataWriter::GetVarInt62Len(frame.ietf_error_code); | 
 |   } | 
 |   return kQuicFrameTypeSize + kQuicMaxStreamIdSize + kQuicMaxStreamOffsetSize + | 
 |          kQuicErrorCodeSize; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetConnectionCloseFrameSize( | 
 |     QuicTransportVersion version, | 
 |     const QuicConnectionCloseFrame& frame) { | 
 |   if (!VersionHasIetfQuicFrames(version)) { | 
 |     // Not IETF QUIC, return Google QUIC CONNECTION CLOSE frame size. | 
 |     return kQuicFrameTypeSize + kQuicErrorCodeSize + | 
 |            kQuicErrorDetailsLengthSize + | 
 |            TruncatedErrorStringSize(frame.error_details); | 
 |   } | 
 |  | 
 |   // Prepend the extra error information to the string and get the result's | 
 |   // length. | 
 |   const size_t truncated_error_string_size = TruncatedErrorStringSize( | 
 |       GenerateErrorString(frame.error_details, frame.quic_error_code)); | 
 |  | 
 |   const size_t frame_size = | 
 |       truncated_error_string_size + | 
 |       QuicDataWriter::GetVarInt62Len(truncated_error_string_size) + | 
 |       kQuicFrameTypeSize + | 
 |       QuicDataWriter::GetVarInt62Len(frame.wire_error_code); | 
 |   if (frame.close_type == IETF_QUIC_APPLICATION_CONNECTION_CLOSE) { | 
 |     return frame_size; | 
 |   } | 
 |   // The Transport close frame has the transport_close_frame_type, so include | 
 |   // its length. | 
 |   return frame_size + | 
 |          QuicDataWriter::GetVarInt62Len(frame.transport_close_frame_type); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMinGoAwayFrameSize() { | 
 |   return kQuicFrameTypeSize + kQuicErrorCodeSize + kQuicErrorDetailsLengthSize + | 
 |          kQuicMaxStreamIdSize; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetWindowUpdateFrameSize( | 
 |     QuicTransportVersion version, | 
 |     const QuicWindowUpdateFrame& frame) { | 
 |   if (!VersionHasIetfQuicFrames(version)) { | 
 |     return kQuicFrameTypeSize + kQuicMaxStreamIdSize + kQuicMaxStreamOffsetSize; | 
 |   } | 
 |   if (frame.stream_id == QuicUtils::GetInvalidStreamId(version)) { | 
 |     // Frame would be a MAX DATA frame, which has only a Maximum Data field. | 
 |     return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(frame.max_data); | 
 |   } | 
 |   // Frame would be MAX STREAM DATA, has Maximum Stream Data and Stream ID | 
 |   // fields. | 
 |   return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(frame.max_data) + | 
 |          QuicDataWriter::GetVarInt62Len(frame.stream_id); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetMaxStreamsFrameSize(QuicTransportVersion version, | 
 |                                           const QuicMaxStreamsFrame& frame) { | 
 |   if (!VersionHasIetfQuicFrames(version)) { | 
 |     QUIC_BUG << "In version " << version | 
 |              << ", which does not support IETF Frames, and tried to serialize " | 
 |                 "MaxStreams Frame."; | 
 |   } | 
 |   return kQuicFrameTypeSize + | 
 |          QuicDataWriter::GetVarInt62Len(frame.stream_count); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetStreamsBlockedFrameSize( | 
 |     QuicTransportVersion version, | 
 |     const QuicStreamsBlockedFrame& frame) { | 
 |   if (!VersionHasIetfQuicFrames(version)) { | 
 |     QUIC_BUG << "In version " << version | 
 |              << ", which does not support IETF frames, and tried to serialize " | 
 |                 "StreamsBlocked Frame."; | 
 |   } | 
 |  | 
 |   return kQuicFrameTypeSize + | 
 |          QuicDataWriter::GetVarInt62Len(frame.stream_count); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetBlockedFrameSize(QuicTransportVersion version, | 
 |                                        const QuicBlockedFrame& frame) { | 
 |   if (!VersionHasIetfQuicFrames(version)) { | 
 |     return kQuicFrameTypeSize + kQuicMaxStreamIdSize; | 
 |   } | 
 |   if (frame.stream_id == QuicUtils::GetInvalidStreamId(version)) { | 
 |     // return size of IETF QUIC Blocked frame | 
 |     return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(frame.offset); | 
 |   } | 
 |   // return size of IETF QUIC Stream Blocked frame. | 
 |   return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(frame.offset) + | 
 |          QuicDataWriter::GetVarInt62Len(frame.stream_id); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetStopSendingFrameSize(const QuicStopSendingFrame& frame) { | 
 |   return kQuicFrameTypeSize + QuicDataWriter::GetVarInt62Len(frame.stream_id) + | 
 |          QuicDataWriter::GetVarInt62Len(frame.application_error_code); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetPathChallengeFrameSize( | 
 |     const QuicPathChallengeFrame& frame) { | 
 |   return kQuicFrameTypeSize + sizeof(frame.data_buffer); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetPathResponseFrameSize( | 
 |     const QuicPathResponseFrame& frame) { | 
 |   return kQuicFrameTypeSize + sizeof(frame.data_buffer); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetRetransmittableControlFrameSize( | 
 |     QuicTransportVersion version, | 
 |     const QuicFrame& frame) { | 
 |   switch (frame.type) { | 
 |     case PING_FRAME: | 
 |       // Ping has no payload. | 
 |       return kQuicFrameTypeSize; | 
 |     case RST_STREAM_FRAME: | 
 |       return GetRstStreamFrameSize(version, *frame.rst_stream_frame); | 
 |     case CONNECTION_CLOSE_FRAME: | 
 |       return GetConnectionCloseFrameSize(version, | 
 |                                          *frame.connection_close_frame); | 
 |     case GOAWAY_FRAME: | 
 |       return GetMinGoAwayFrameSize() + | 
 |              TruncatedErrorStringSize(frame.goaway_frame->reason_phrase); | 
 |     case WINDOW_UPDATE_FRAME: | 
 |       // For IETF QUIC, this could be either a MAX DATA or MAX STREAM DATA. | 
 |       // GetWindowUpdateFrameSize figures this out and returns the correct | 
 |       // length. | 
 |       return GetWindowUpdateFrameSize(version, *frame.window_update_frame); | 
 |     case BLOCKED_FRAME: | 
 |       return GetBlockedFrameSize(version, *frame.blocked_frame); | 
 |     case NEW_CONNECTION_ID_FRAME: | 
 |       return GetNewConnectionIdFrameSize(*frame.new_connection_id_frame); | 
 |     case RETIRE_CONNECTION_ID_FRAME: | 
 |       return GetRetireConnectionIdFrameSize(*frame.retire_connection_id_frame); | 
 |     case NEW_TOKEN_FRAME: | 
 |       return GetNewTokenFrameSize(*frame.new_token_frame); | 
 |     case MAX_STREAMS_FRAME: | 
 |       return GetMaxStreamsFrameSize(version, frame.max_streams_frame); | 
 |     case STREAMS_BLOCKED_FRAME: | 
 |       return GetStreamsBlockedFrameSize(version, frame.streams_blocked_frame); | 
 |     case PATH_RESPONSE_FRAME: | 
 |       return GetPathResponseFrameSize(*frame.path_response_frame); | 
 |     case PATH_CHALLENGE_FRAME: | 
 |       return GetPathChallengeFrameSize(*frame.path_challenge_frame); | 
 |     case STOP_SENDING_FRAME: | 
 |       return GetStopSendingFrameSize(*frame.stop_sending_frame); | 
 |     case HANDSHAKE_DONE_FRAME: | 
 |       // HANDSHAKE_DONE has no payload. | 
 |       return kQuicFrameTypeSize; | 
 |  | 
 |     case STREAM_FRAME: | 
 |     case ACK_FRAME: | 
 |     case STOP_WAITING_FRAME: | 
 |     case MTU_DISCOVERY_FRAME: | 
 |     case PADDING_FRAME: | 
 |     case MESSAGE_FRAME: | 
 |     case CRYPTO_FRAME: | 
 |     case NUM_FRAME_TYPES: | 
 |       DCHECK(false); | 
 |       return 0; | 
 |   } | 
 |  | 
 |   // Not reachable, but some Chrome compilers can't figure that out.  *sigh* | 
 |   DCHECK(false); | 
 |   return 0; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetStreamIdSize(QuicStreamId stream_id) { | 
 |   // Sizes are 1 through 4 bytes. | 
 |   for (int i = 1; i <= 4; ++i) { | 
 |     stream_id >>= 8; | 
 |     if (stream_id == 0) { | 
 |       return i; | 
 |     } | 
 |   } | 
 |   QUIC_BUG << "Failed to determine StreamIDSize."; | 
 |   return 4; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetStreamOffsetSize(QuicStreamOffset offset) { | 
 |   // 0 is a special case. | 
 |   if (offset == 0) { | 
 |     return 0; | 
 |   } | 
 |   // 2 through 8 are the remaining sizes. | 
 |   offset >>= 8; | 
 |   for (int i = 2; i <= 8; ++i) { | 
 |     offset >>= 8; | 
 |     if (offset == 0) { | 
 |       return i; | 
 |     } | 
 |   } | 
 |   QUIC_BUG << "Failed to determine StreamOffsetSize."; | 
 |   return 8; | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetNewConnectionIdFrameSize( | 
 |     const QuicNewConnectionIdFrame& frame) { | 
 |   return kQuicFrameTypeSize + | 
 |          QuicDataWriter::GetVarInt62Len(frame.sequence_number) + | 
 |          QuicDataWriter::GetVarInt62Len(frame.retire_prior_to) + | 
 |          kConnectionIdLengthSize + frame.connection_id.length() + | 
 |          sizeof(frame.stateless_reset_token); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetRetireConnectionIdFrameSize( | 
 |     const QuicRetireConnectionIdFrame& frame) { | 
 |   return kQuicFrameTypeSize + | 
 |          QuicDataWriter::GetVarInt62Len(frame.sequence_number); | 
 | } | 
 |  | 
 | // static | 
 | size_t QuicFramer::GetNewTokenFrameSize(const QuicNewTokenFrame& frame) { | 
 |   return kQuicFrameTypeSize + | 
 |          QuicDataWriter::GetVarInt62Len(frame.token.length()) + | 
 |          frame.token.length(); | 
 | } | 
 |  | 
 | // TODO(nharper): Change this method to take a ParsedQuicVersion. | 
 | bool QuicFramer::IsSupportedTransportVersion( | 
 |     const QuicTransportVersion version) const { | 
 |   for (ParsedQuicVersion supported_version : supported_versions_) { | 
 |     if (version == supported_version.transport_version) { | 
 |       return true; | 
 |     } | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool QuicFramer::IsSupportedVersion(const ParsedQuicVersion version) const { | 
 |   for (const ParsedQuicVersion& supported_version : supported_versions_) { | 
 |     if (version == supported_version) { | 
 |       return true; | 
 |     } | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | size_t QuicFramer::GetSerializedFrameLength( | 
 |     const QuicFrame& frame, | 
 |     size_t free_bytes, | 
 |     bool first_frame, | 
 |     bool last_frame, | 
 |     QuicPacketNumberLength packet_number_length) { | 
 |   // Prevent a rare crash reported in b/19458523. | 
 |   if (frame.type == ACK_FRAME && frame.ack_frame == nullptr) { | 
 |     QUIC_BUG << "Cannot compute the length of a null ack frame. free_bytes:" | 
 |              << free_bytes << " first_frame:" << first_frame | 
 |              << " last_frame:" << last_frame | 
 |              << " seq num length:" << packet_number_length; | 
 |     set_error(QUIC_INTERNAL_ERROR); | 
 |     visitor_->OnError(this); | 
 |     return 0; | 
 |   } | 
 |   if (frame.type == PADDING_FRAME) { | 
 |     if (frame.padding_frame.num_padding_bytes == -1) { | 
 |       // Full padding to the end of the packet. | 
 |       return free_bytes; | 
 |     } else { | 
 |       // Lite padding. | 
 |       return free_bytes < | 
 |                      static_cast<size_t>(frame.padding_frame.num_padding_bytes) | 
 |                  ? free_bytes | 
 |                  : frame.padding_frame.num_padding_bytes; | 
 |     } | 
 |   } | 
 |  | 
 |   size_t frame_len = | 
 |       ComputeFrameLength(frame, last_frame, packet_number_length); | 
 |   if (frame_len <= free_bytes) { | 
 |     // Frame fits within packet. Note that acks may be truncated. | 
 |     return frame_len; | 
 |   } | 
 |   // Only truncate the first frame in a packet, so if subsequent ones go | 
 |   // over, stop including more frames. | 
 |   if (!first_frame) { | 
 |     return 0; | 
 |   } | 
 |   bool can_truncate = | 
 |       frame.type == ACK_FRAME && | 
 |       free_bytes >= GetMinAckFrameSize(version_.transport_version, | 
 |                                        *frame.ack_frame, | 
 |                                        local_ack_delay_exponent_); | 
 |   if (can_truncate) { | 
 |     // Truncate the frame so the packet will not exceed kMaxOutgoingPacketSize. | 
 |     // Note that we may not use every byte of the writer in this case. | 
 |     QUIC_DLOG(INFO) << ENDPOINT | 
 |                     << "Truncating large frame, free bytes: " << free_bytes; | 
 |     return free_bytes; | 
 |   } | 
 |   return 0; | 
 | } | 
 |  | 
 | QuicFramer::AckFrameInfo::AckFrameInfo() | 
 |     : max_block_length(0), first_block_length(0), num_ack_blocks(0) {} | 
 |  | 
 | QuicFramer::AckFrameInfo::AckFrameInfo(const AckFrameInfo& other) = default; | 
 |  | 
 | QuicFramer::AckFrameInfo::~AckFrameInfo() {} | 
 |  | 
 | bool QuicFramer::WriteIetfLongHeaderLength(const QuicPacketHeader& header, | 
 |                                            QuicDataWriter* writer, | 
 |                                            size_t length_field_offset, | 
 |                                            EncryptionLevel level) { | 
 |   if (!QuicVersionHasLongHeaderLengths(transport_version()) || | 
 |       !header.version_flag || length_field_offset == 0) { | 
 |     return true; | 
 |   } | 
 |   if (writer->length() < length_field_offset || | 
 |       writer->length() - length_field_offset < | 
 |           kQuicDefaultLongHeaderLengthLength) { | 
 |     set_detailed_error("Invalid length_field_offset."); | 
 |     QUIC_BUG << "Invalid length_field_offset."; | 
 |     return false; | 
 |   } | 
 |   size_t length_to_write = writer->length() - length_field_offset - | 
 |                            kQuicDefaultLongHeaderLengthLength; | 
 |   // Add length of auth tag. | 
 |   length_to_write = GetCiphertextSize(level, length_to_write); | 
 |  | 
 |   QuicDataWriter length_writer(writer->length() - length_field_offset, | 
 |                                writer->data() + length_field_offset); | 
 |   if (!length_writer.WriteVarInt62(length_to_write, | 
 |                                    kQuicDefaultLongHeaderLengthLength)) { | 
 |     set_detailed_error("Failed to overwrite long header length."); | 
 |     QUIC_BUG << "Failed to overwrite long header length."; | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | size_t QuicFramer::BuildDataPacket(const QuicPacketHeader& header, | 
 |                                    const QuicFrames& frames, | 
 |                                    char* buffer, | 
 |                                    size_t packet_length, | 
 |                                    EncryptionLevel level) { | 
 |   QUIC_BUG_IF(header.version_flag && | 
 |               VersionHasIetfInvariantHeader(transport_version()) && | 
 |               header.long_packet_type == RETRY && !frames.empty()) | 
 |       << "IETF RETRY packets cannot contain frames " << header; | 
 |   QuicDataWriter writer(packet_length, buffer); | 
 |   size_t length_field_offset = 0; | 
 |   if (!AppendPacketHeader(header, &writer, &length_field_offset)) { | 
 |     QUIC_BUG << "AppendPacketHeader failed"; | 
 |     return 0; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     if (AppendIetfFrames(frames, &writer) == 0) { | 
 |       return 0; | 
 |     } | 
 |     if (!WriteIetfLongHeaderLength(header, &writer, length_field_offset, | 
 |                                    level)) { | 
 |       return 0; | 
 |     } | 
 |     return writer.length(); | 
 |   } | 
 |  | 
 |   size_t i = 0; | 
 |   for (const QuicFrame& frame : frames) { | 
 |     // Determine if we should write stream frame length in header. | 
 |     const bool last_frame_in_packet = i == frames.size() - 1; | 
 |     if (!AppendTypeByte(frame, last_frame_in_packet, &writer)) { | 
 |       QUIC_BUG << "AppendTypeByte failed"; | 
 |       return 0; | 
 |     } | 
 |  | 
 |     switch (frame.type) { | 
 |       case PADDING_FRAME: | 
 |         if (!AppendPaddingFrame(frame.padding_frame, &writer)) { | 
 |           QUIC_BUG << "AppendPaddingFrame of " | 
 |                    << frame.padding_frame.num_padding_bytes << " failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STREAM_FRAME: | 
 |         if (!AppendStreamFrame(frame.stream_frame, last_frame_in_packet, | 
 |                                &writer)) { | 
 |           QUIC_BUG << "AppendStreamFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case ACK_FRAME: | 
 |         if (!AppendAckFrameAndTypeByte(*frame.ack_frame, &writer)) { | 
 |           QUIC_BUG << "AppendAckFrameAndTypeByte failed: " << detailed_error_; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STOP_WAITING_FRAME: | 
 |         if (!AppendStopWaitingFrame(header, frame.stop_waiting_frame, | 
 |                                     &writer)) { | 
 |           QUIC_BUG << "AppendStopWaitingFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case MTU_DISCOVERY_FRAME: | 
 |         // MTU discovery frames are serialized as ping frames. | 
 |         QUIC_FALLTHROUGH_INTENDED; | 
 |       case PING_FRAME: | 
 |         // Ping has no payload. | 
 |         break; | 
 |       case RST_STREAM_FRAME: | 
 |         if (!AppendRstStreamFrame(*frame.rst_stream_frame, &writer)) { | 
 |           QUIC_BUG << "AppendRstStreamFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case CONNECTION_CLOSE_FRAME: | 
 |         if (!AppendConnectionCloseFrame(*frame.connection_close_frame, | 
 |                                         &writer)) { | 
 |           QUIC_BUG << "AppendConnectionCloseFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case GOAWAY_FRAME: | 
 |         if (!AppendGoAwayFrame(*frame.goaway_frame, &writer)) { | 
 |           QUIC_BUG << "AppendGoAwayFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case WINDOW_UPDATE_FRAME: | 
 |         if (!AppendWindowUpdateFrame(*frame.window_update_frame, &writer)) { | 
 |           QUIC_BUG << "AppendWindowUpdateFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case BLOCKED_FRAME: | 
 |         if (!AppendBlockedFrame(*frame.blocked_frame, &writer)) { | 
 |           QUIC_BUG << "AppendBlockedFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case NEW_CONNECTION_ID_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append NEW_CONNECTION_ID frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case RETIRE_CONNECTION_ID_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append RETIRE_CONNECTION_ID frame and not in IETF " | 
 |             "QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case NEW_TOKEN_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append NEW_TOKEN_ID frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case MAX_STREAMS_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append MAX_STREAMS frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case STREAMS_BLOCKED_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append STREAMS_BLOCKED frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case PATH_RESPONSE_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append PATH_RESPONSE frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case PATH_CHALLENGE_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append PATH_CHALLENGE frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case STOP_SENDING_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append STOP_SENDING frame and not in IETF QUIC."); | 
 |         return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       case MESSAGE_FRAME: | 
 |         if (!AppendMessageFrameAndTypeByte(*frame.message_frame, | 
 |                                            last_frame_in_packet, &writer)) { | 
 |           QUIC_BUG << "AppendMessageFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case CRYPTO_FRAME: | 
 |         if (!QuicVersionUsesCryptoFrames(version_.transport_version)) { | 
 |           set_detailed_error( | 
 |               "Attempt to append CRYPTO frame in version prior to 47."); | 
 |           return RaiseError(QUIC_INTERNAL_ERROR); | 
 |         } | 
 |         if (!AppendCryptoFrame(*frame.crypto_frame, &writer)) { | 
 |           QUIC_BUG << "AppendCryptoFrame failed"; | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       default: | 
 |         RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |         QUIC_BUG << "QUIC_INVALID_FRAME_DATA"; | 
 |         return 0; | 
 |     } | 
 |     ++i; | 
 |   } | 
 |  | 
 |   if (!WriteIetfLongHeaderLength(header, &writer, length_field_offset, level)) { | 
 |     return 0; | 
 |   } | 
 |  | 
 |   return writer.length(); | 
 | } | 
 |  | 
 | size_t QuicFramer::AppendIetfFrames(const QuicFrames& frames, | 
 |                                     QuicDataWriter* writer) { | 
 |   size_t i = 0; | 
 |   for (const QuicFrame& frame : frames) { | 
 |     // Determine if we should write stream frame length in header. | 
 |     const bool last_frame_in_packet = i == frames.size() - 1; | 
 |     if (!AppendIetfTypeByte(frame, last_frame_in_packet, writer)) { | 
 |       QUIC_BUG << "AppendIetfTypeByte failed: " << detailed_error(); | 
 |       return 0; | 
 |     } | 
 |  | 
 |     switch (frame.type) { | 
 |       case PADDING_FRAME: | 
 |         if (!AppendPaddingFrame(frame.padding_frame, writer)) { | 
 |           QUIC_BUG << "AppendPaddingFrame of " | 
 |                    << frame.padding_frame.num_padding_bytes | 
 |                    << " failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STREAM_FRAME: | 
 |         if (!AppendStreamFrame(frame.stream_frame, last_frame_in_packet, | 
 |                                writer)) { | 
 |           QUIC_BUG << "AppendStreamFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case ACK_FRAME: | 
 |         if (!AppendIetfAckFrameAndTypeByte(*frame.ack_frame, writer)) { | 
 |           QUIC_BUG << "AppendIetfAckFrameAndTypeByte failed: " | 
 |                    << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STOP_WAITING_FRAME: | 
 |         set_detailed_error( | 
 |             "Attempt to append STOP WAITING frame in IETF QUIC."); | 
 |         RaiseError(QUIC_INTERNAL_ERROR); | 
 |         QUIC_BUG << detailed_error(); | 
 |         return 0; | 
 |       case MTU_DISCOVERY_FRAME: | 
 |         // MTU discovery frames are serialized as ping frames. | 
 |         QUIC_FALLTHROUGH_INTENDED; | 
 |       case PING_FRAME: | 
 |         // Ping has no payload. | 
 |         break; | 
 |       case RST_STREAM_FRAME: | 
 |         if (!AppendRstStreamFrame(*frame.rst_stream_frame, writer)) { | 
 |           QUIC_BUG << "AppendRstStreamFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case CONNECTION_CLOSE_FRAME: | 
 |         if (!AppendIetfConnectionCloseFrame(*frame.connection_close_frame, | 
 |                                             writer)) { | 
 |           QUIC_BUG << "AppendIetfConnectionCloseFrame failed: " | 
 |                    << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case GOAWAY_FRAME: | 
 |         set_detailed_error("Attempt to append GOAWAY frame in IETF QUIC."); | 
 |         RaiseError(QUIC_INTERNAL_ERROR); | 
 |         QUIC_BUG << detailed_error(); | 
 |         return 0; | 
 |       case WINDOW_UPDATE_FRAME: | 
 |         // Depending on whether there is a stream ID or not, will be either a | 
 |         // MAX STREAM DATA frame or a MAX DATA frame. | 
 |         if (frame.window_update_frame->stream_id == | 
 |             QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |           if (!AppendMaxDataFrame(*frame.window_update_frame, writer)) { | 
 |             QUIC_BUG << "AppendMaxDataFrame failed: " << detailed_error(); | 
 |             return 0; | 
 |           } | 
 |         } else { | 
 |           if (!AppendMaxStreamDataFrame(*frame.window_update_frame, writer)) { | 
 |             QUIC_BUG << "AppendMaxStreamDataFrame failed: " << detailed_error(); | 
 |             return 0; | 
 |           } | 
 |         } | 
 |         break; | 
 |       case BLOCKED_FRAME: | 
 |         if (!AppendBlockedFrame(*frame.blocked_frame, writer)) { | 
 |           QUIC_BUG << "AppendBlockedFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case MAX_STREAMS_FRAME: | 
 |         if (!AppendMaxStreamsFrame(frame.max_streams_frame, writer)) { | 
 |           QUIC_BUG << "AppendMaxStreamsFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STREAMS_BLOCKED_FRAME: | 
 |         if (!AppendStreamsBlockedFrame(frame.streams_blocked_frame, writer)) { | 
 |           QUIC_BUG << "AppendStreamsBlockedFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case NEW_CONNECTION_ID_FRAME: | 
 |         if (!AppendNewConnectionIdFrame(*frame.new_connection_id_frame, | 
 |                                         writer)) { | 
 |           QUIC_BUG << "AppendNewConnectionIdFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case RETIRE_CONNECTION_ID_FRAME: | 
 |         if (!AppendRetireConnectionIdFrame(*frame.retire_connection_id_frame, | 
 |                                            writer)) { | 
 |           QUIC_BUG << "AppendRetireConnectionIdFrame failed: " | 
 |                    << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case NEW_TOKEN_FRAME: | 
 |         if (!AppendNewTokenFrame(*frame.new_token_frame, writer)) { | 
 |           QUIC_BUG << "AppendNewTokenFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case STOP_SENDING_FRAME: | 
 |         if (!AppendStopSendingFrame(*frame.stop_sending_frame, writer)) { | 
 |           QUIC_BUG << "AppendStopSendingFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case PATH_CHALLENGE_FRAME: | 
 |         if (!AppendPathChallengeFrame(*frame.path_challenge_frame, writer)) { | 
 |           QUIC_BUG << "AppendPathChallengeFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case PATH_RESPONSE_FRAME: | 
 |         if (!AppendPathResponseFrame(*frame.path_response_frame, writer)) { | 
 |           QUIC_BUG << "AppendPathResponseFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case MESSAGE_FRAME: | 
 |         if (!AppendMessageFrameAndTypeByte(*frame.message_frame, | 
 |                                            last_frame_in_packet, writer)) { | 
 |           QUIC_BUG << "AppendMessageFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case CRYPTO_FRAME: | 
 |         if (!AppendCryptoFrame(*frame.crypto_frame, writer)) { | 
 |           QUIC_BUG << "AppendCryptoFrame failed: " << detailed_error(); | 
 |           return 0; | 
 |         } | 
 |         break; | 
 |       case HANDSHAKE_DONE_FRAME: | 
 |         // HANDSHAKE_DONE has no payload. | 
 |         break; | 
 |       default: | 
 |         set_detailed_error("Tried to append unknown frame type."); | 
 |         RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |         QUIC_BUG << "QUIC_INVALID_FRAME_DATA: " << frame.type; | 
 |         return 0; | 
 |     } | 
 |     ++i; | 
 |   } | 
 |  | 
 |   return writer->length(); | 
 | } | 
 |  | 
 | // static | 
 | std::unique_ptr<QuicEncryptedPacket> QuicFramer::BuildPublicResetPacket( | 
 |     const QuicPublicResetPacket& packet) { | 
 |   CryptoHandshakeMessage reset; | 
 |   reset.set_tag(kPRST); | 
 |   reset.SetValue(kRNON, packet.nonce_proof); | 
 |   if (packet.client_address.host().address_family() != | 
 |       IpAddressFamily::IP_UNSPEC) { | 
 |     // packet.client_address is non-empty. | 
 |     QuicSocketAddressCoder address_coder(packet.client_address); | 
 |     std::string serialized_address = address_coder.Encode(); | 
 |     if (serialized_address.empty()) { | 
 |       return nullptr; | 
 |     } | 
 |     reset.SetStringPiece(kCADR, serialized_address); | 
 |   } | 
 |   if (!packet.endpoint_id.empty()) { | 
 |     reset.SetStringPiece(kEPID, packet.endpoint_id); | 
 |   } | 
 |   const QuicData& reset_serialized = reset.GetSerialized(); | 
 |  | 
 |   size_t len = kPublicFlagsSize + packet.connection_id.length() + | 
 |                reset_serialized.length(); | 
 |   std::unique_ptr<char[]> buffer(new char[len]); | 
 |   QuicDataWriter writer(len, buffer.get()); | 
 |  | 
 |   uint8_t flags = static_cast<uint8_t>(PACKET_PUBLIC_FLAGS_RST | | 
 |                                        PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID); | 
 |   // This hack makes post-v33 public reset packet look like pre-v33 packets. | 
 |   flags |= static_cast<uint8_t>(PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD); | 
 |   if (!writer.WriteUInt8(flags)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!writer.WriteConnectionId(packet.connection_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!writer.WriteBytes(reset_serialized.data(), reset_serialized.length())) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   return std::make_unique<QuicEncryptedPacket>(buffer.release(), len, true); | 
 | } | 
 |  | 
 | // static | 
 | std::unique_ptr<QuicEncryptedPacket> QuicFramer::BuildIetfStatelessResetPacket( | 
 |     QuicConnectionId /*connection_id*/, | 
 |     QuicUint128 stateless_reset_token) { | 
 |   QUIC_DVLOG(1) << "Building IETF stateless reset packet."; | 
 |   size_t len = kPacketHeaderTypeSize + kMinRandomBytesLengthInStatelessReset + | 
 |                sizeof(stateless_reset_token); | 
 |   std::unique_ptr<char[]> buffer(new char[len]); | 
 |   QuicDataWriter writer(len, buffer.get()); | 
 |  | 
 |   uint8_t type = 0; | 
 |   type |= FLAGS_FIXED_BIT; | 
 |   type |= FLAGS_SHORT_HEADER_RESERVED_1; | 
 |   type |= FLAGS_SHORT_HEADER_RESERVED_2; | 
 |   type |= PacketNumberLengthToOnWireValue(PACKET_1BYTE_PACKET_NUMBER); | 
 |  | 
 |   // Append type byte. | 
 |   if (!writer.WriteUInt8(type)) { | 
 |     return nullptr; | 
 |   } | 
 |   // Append random bytes. | 
 |   if (!writer.WriteRandomBytes(QuicRandom::GetInstance(), | 
 |                                kMinRandomBytesLengthInStatelessReset)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   // Append stateless reset token. | 
 |   if (!writer.WriteBytes(&stateless_reset_token, | 
 |                          sizeof(stateless_reset_token))) { | 
 |     return nullptr; | 
 |   } | 
 |   return std::make_unique<QuicEncryptedPacket>(buffer.release(), len, true); | 
 | } | 
 |  | 
 | // static | 
 | std::unique_ptr<QuicEncryptedPacket> QuicFramer::BuildVersionNegotiationPacket( | 
 |     QuicConnectionId server_connection_id, | 
 |     QuicConnectionId client_connection_id, | 
 |     bool ietf_quic, | 
 |     bool use_length_prefix, | 
 |     const ParsedQuicVersionVector& versions) { | 
 |   ParsedQuicVersionVector wire_versions = versions; | 
 |   // Add a version reserved for negotiation as suggested by the | 
 |   // "Using Reserved Versions" section of draft-ietf-quic-transport. | 
 |   if (wire_versions.empty()) { | 
 |     // Ensure that version negotiation packets we send have at least two | 
 |     // versions. This guarantees that, under all circumstances, all QUIC | 
 |     // packets we send are at least 14 bytes long. | 
 |     wire_versions = {QuicVersionReservedForNegotiation(), | 
 |                      QuicVersionReservedForNegotiation()}; | 
 |   } else { | 
 |     // This is not uniformely distributed but is acceptable since no security | 
 |     // depends on this randomness. | 
 |     size_t version_index = 0; | 
 |     const bool disable_randomness = | 
 |         GetQuicFlag(FLAGS_quic_disable_version_negotiation_grease_randomness); | 
 |     if (!disable_randomness) { | 
 |       version_index = | 
 |           QuicRandom::GetInstance()->RandUint64() % (wire_versions.size() + 1); | 
 |     } | 
 |     wire_versions.insert(wire_versions.begin() + version_index, | 
 |                          QuicVersionReservedForNegotiation()); | 
 |   } | 
 |   if (ietf_quic) { | 
 |     return BuildIetfVersionNegotiationPacket( | 
 |         use_length_prefix, server_connection_id, client_connection_id, | 
 |         wire_versions); | 
 |   } | 
 |  | 
 |   // The GQUIC encoding does not support encoding client connection IDs. | 
 |   DCHECK(client_connection_id.IsEmpty()); | 
 |   // The GQUIC encoding does not support length-prefixed connection IDs. | 
 |   DCHECK(!use_length_prefix); | 
 |  | 
 |   DCHECK(!wire_versions.empty()); | 
 |   size_t len = kPublicFlagsSize + server_connection_id.length() + | 
 |                wire_versions.size() * kQuicVersionSize; | 
 |   std::unique_ptr<char[]> buffer(new char[len]); | 
 |   QuicDataWriter writer(len, buffer.get()); | 
 |  | 
 |   uint8_t flags = static_cast<uint8_t>( | 
 |       PACKET_PUBLIC_FLAGS_VERSION | PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID | | 
 |       PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD); | 
 |   if (!writer.WriteUInt8(flags)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!writer.WriteConnectionId(server_connection_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   for (const ParsedQuicVersion& version : wire_versions) { | 
 |     if (!writer.WriteUInt32(CreateQuicVersionLabel(version))) { | 
 |       return nullptr; | 
 |     } | 
 |   } | 
 |  | 
 |   return std::make_unique<QuicEncryptedPacket>(buffer.release(), len, true); | 
 | } | 
 |  | 
 | // static | 
 | std::unique_ptr<QuicEncryptedPacket> | 
 | QuicFramer::BuildIetfVersionNegotiationPacket( | 
 |     bool use_length_prefix, | 
 |     QuicConnectionId server_connection_id, | 
 |     QuicConnectionId client_connection_id, | 
 |     const ParsedQuicVersionVector& versions) { | 
 |   QUIC_DVLOG(1) << "Building IETF version negotiation packet with" | 
 |                 << (use_length_prefix ? "" : "out") | 
 |                 << " length prefix, server_connection_id " | 
 |                 << server_connection_id << " client_connection_id " | 
 |                 << client_connection_id << " versions " | 
 |                 << ParsedQuicVersionVectorToString(versions); | 
 |   DCHECK(!versions.empty()); | 
 |   size_t len = kPacketHeaderTypeSize + kConnectionIdLengthSize + | 
 |                client_connection_id.length() + server_connection_id.length() + | 
 |                (versions.size() + 1) * kQuicVersionSize; | 
 |   if (use_length_prefix) { | 
 |     // When using length-prefixed connection IDs, packets carry two lengths | 
 |     // instead of one. | 
 |     len += kConnectionIdLengthSize; | 
 |   } | 
 |   std::unique_ptr<char[]> buffer(new char[len]); | 
 |   QuicDataWriter writer(len, buffer.get()); | 
 |  | 
 |   // TODO(fayang): Randomly select a value for the type. | 
 |   uint8_t type = static_cast<uint8_t>(FLAGS_LONG_HEADER | FLAGS_FIXED_BIT); | 
 |   if (!writer.WriteUInt8(type)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!writer.WriteUInt32(0)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!AppendIetfConnectionIds(true, use_length_prefix, client_connection_id, | 
 |                                server_connection_id, &writer)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   for (const ParsedQuicVersion& version : versions) { | 
 |     if (!writer.WriteUInt32(CreateQuicVersionLabel(version))) { | 
 |       return nullptr; | 
 |     } | 
 |   } | 
 |  | 
 |   return std::make_unique<QuicEncryptedPacket>(buffer.release(), len, true); | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessPacket(const QuicEncryptedPacket& packet) { | 
 |   QuicDataReader reader(packet.data(), packet.length()); | 
 |  | 
 |   bool packet_has_ietf_packet_header = false; | 
 |   if (infer_packet_header_type_from_version_) { | 
 |     packet_has_ietf_packet_header = | 
 |         VersionHasIetfInvariantHeader(version_.transport_version); | 
 |   } else if (!reader.IsDoneReading()) { | 
 |     uint8_t type = reader.PeekByte(); | 
 |     packet_has_ietf_packet_header = QuicUtils::IsIetfPacketHeader(type); | 
 |   } | 
 |   if (packet_has_ietf_packet_header) { | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Processing IETF QUIC packet."; | 
 |   } | 
 |  | 
 |   visitor_->OnPacket(); | 
 |  | 
 |   QuicPacketHeader header; | 
 |   if (!ProcessPublicHeader(&reader, packet_has_ietf_packet_header, &header)) { | 
 |     DCHECK_NE("", detailed_error_); | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Unable to process public header. Error: " | 
 |                   << detailed_error_; | 
 |     DCHECK_NE("", detailed_error_); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PUBLIC_HEADER); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |  | 
 |   if (!visitor_->OnUnauthenticatedPublicHeader(header)) { | 
 |     // The visitor suppresses further processing of the packet. | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (IsVersionNegotiation(header, packet_has_ietf_packet_header)) { | 
 |     if (perspective_ == Perspective::IS_CLIENT) { | 
 |       QUIC_DVLOG(1) << "Client received version negotiation packet"; | 
 |       return ProcessVersionNegotiationPacket(&reader, header); | 
 |     } else { | 
 |       QUIC_DLOG(ERROR) << "Server received version negotiation packet"; | 
 |       set_detailed_error("Server received version negotiation packet."); | 
 |       return RaiseError(QUIC_INVALID_VERSION_NEGOTIATION_PACKET); | 
 |     } | 
 |   } | 
 |  | 
 |   if (header.version_flag && header.version != version_) { | 
 |     if (perspective_ == Perspective::IS_SERVER) { | 
 |       if (!visitor_->OnProtocolVersionMismatch(header.version)) { | 
 |         RecordDroppedPacketReason(DroppedPacketReason::VERSION_MISMATCH); | 
 |         return true; | 
 |       } | 
 |     } else { | 
 |       // A client received a packet of a different version but that packet is | 
 |       // not a version negotiation packet. It is therefore invalid and dropped. | 
 |       QUIC_DLOG(ERROR) << "Client received unexpected version " | 
 |                        << ParsedQuicVersionToString(header.version) | 
 |                        << " instead of " << ParsedQuicVersionToString(version_); | 
 |       set_detailed_error("Client received unexpected version."); | 
 |       return RaiseError(QUIC_INVALID_VERSION); | 
 |     } | 
 |   } | 
 |  | 
 |   bool rv; | 
 |   if (header.long_packet_type == RETRY) { | 
 |     rv = ProcessRetryPacket(&reader, header); | 
 |   } else if (header.reset_flag) { | 
 |     rv = ProcessPublicResetPacket(&reader, header); | 
 |   } else if (packet.length() <= kMaxIncomingPacketSize) { | 
 |     // The optimized decryption algorithm implementations run faster when | 
 |     // operating on aligned memory. | 
 |     QUIC_CACHELINE_ALIGNED char buffer[kMaxIncomingPacketSize]; | 
 |     if (packet_has_ietf_packet_header) { | 
 |       rv = ProcessIetfDataPacket(&reader, &header, packet, buffer, | 
 |                                  QUICHE_ARRAYSIZE(buffer)); | 
 |     } else { | 
 |       rv = ProcessDataPacket(&reader, &header, packet, buffer, | 
 |                              QUICHE_ARRAYSIZE(buffer)); | 
 |     } | 
 |   } else { | 
 |     std::unique_ptr<char[]> large_buffer(new char[packet.length()]); | 
 |     if (packet_has_ietf_packet_header) { | 
 |       rv = ProcessIetfDataPacket(&reader, &header, packet, large_buffer.get(), | 
 |                                  packet.length()); | 
 |     } else { | 
 |       rv = ProcessDataPacket(&reader, &header, packet, large_buffer.get(), | 
 |                              packet.length()); | 
 |     } | 
 |     QUIC_BUG_IF(rv) << "QUIC should never successfully process packets larger" | 
 |                     << "than kMaxIncomingPacketSize. packet size:" | 
 |                     << packet.length(); | 
 |   } | 
 |   return rv; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessVersionNegotiationPacket( | 
 |     QuicDataReader* reader, | 
 |     const QuicPacketHeader& header) { | 
 |   DCHECK_EQ(Perspective::IS_CLIENT, perspective_); | 
 |  | 
 |   QuicVersionNegotiationPacket packet( | 
 |       GetServerConnectionIdAsRecipient(header, perspective_)); | 
 |   // Try reading at least once to raise error if the packet is invalid. | 
 |   do { | 
 |     QuicVersionLabel version_label; | 
 |     if (!ProcessVersionLabel(reader, &version_label)) { | 
 |       set_detailed_error("Unable to read supported version in negotiation."); | 
 |       RecordDroppedPacketReason( | 
 |           DroppedPacketReason::INVALID_VERSION_NEGOTIATION_PACKET); | 
 |       return RaiseError(QUIC_INVALID_VERSION_NEGOTIATION_PACKET); | 
 |     } | 
 |     ParsedQuicVersion parsed_version = ParseQuicVersionLabel(version_label); | 
 |     if (parsed_version != UnsupportedQuicVersion()) { | 
 |       packet.versions.push_back(parsed_version); | 
 |     } | 
 |   } while (!reader->IsDoneReading()); | 
 |  | 
 |   QUIC_DLOG(INFO) << ENDPOINT << "parsed version negotiation: " | 
 |                   << ParsedQuicVersionVectorToString(packet.versions); | 
 |  | 
 |   visitor_->OnVersionNegotiationPacket(packet); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessRetryPacket(QuicDataReader* reader, | 
 |                                     const QuicPacketHeader& header) { | 
 |   DCHECK_EQ(Perspective::IS_CLIENT, perspective_); | 
 |  | 
 |   if (version_.HasRetryIntegrityTag()) { | 
 |     DCHECK(version_.HasLengthPrefixedConnectionIds()) << version_; | 
 |     const size_t bytes_remaining = reader->BytesRemaining(); | 
 |     if (bytes_remaining <= kRetryIntegrityTagLength) { | 
 |       set_detailed_error("Retry packet too short to parse integrity tag."); | 
 |       return false; | 
 |     } | 
 |     const size_t retry_token_length = | 
 |         bytes_remaining - kRetryIntegrityTagLength; | 
 |     DCHECK_GT(retry_token_length, 0u); | 
 |     quiche::QuicheStringPiece retry_token; | 
 |     if (!reader->ReadStringPiece(&retry_token, retry_token_length)) { | 
 |       set_detailed_error("Failed to read retry token."); | 
 |       return false; | 
 |     } | 
 |     quiche::QuicheStringPiece retry_without_tag = | 
 |         reader->PreviouslyReadPayload(); | 
 |     quiche::QuicheStringPiece integrity_tag = reader->ReadRemainingPayload(); | 
 |     DCHECK_EQ(integrity_tag.length(), kRetryIntegrityTagLength); | 
 |     visitor_->OnRetryPacket(EmptyQuicConnectionId(), | 
 |                             header.source_connection_id, retry_token, | 
 |                             integrity_tag, retry_without_tag); | 
 |     return true; | 
 |   } | 
 |  | 
 |   QuicConnectionId original_destination_connection_id; | 
 |   if (version_.HasLengthPrefixedConnectionIds()) { | 
 |     // Parse Original Destination Connection ID. | 
 |     if (!reader->ReadLengthPrefixedConnectionId( | 
 |             &original_destination_connection_id)) { | 
 |       set_detailed_error("Unable to read Original Destination ConnectionId."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     // Parse Original Destination Connection ID Length. | 
 |     uint8_t odcil = header.type_byte & 0xf; | 
 |     if (odcil != 0) { | 
 |       odcil += kConnectionIdLengthAdjustment; | 
 |     } | 
 |  | 
 |     // Parse Original Destination Connection ID. | 
 |     if (!reader->ReadConnectionId(&original_destination_connection_id, odcil)) { | 
 |       set_detailed_error("Unable to read Original Destination ConnectionId."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   if (!QuicUtils::IsConnectionIdValidForVersion( | 
 |           original_destination_connection_id, transport_version())) { | 
 |     set_detailed_error( | 
 |         "Received Original Destination ConnectionId with invalid length."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece retry_token = reader->ReadRemainingPayload(); | 
 |   visitor_->OnRetryPacket(original_destination_connection_id, | 
 |                           header.source_connection_id, retry_token, | 
 |                           /*retry_integrity_tag=*/quiche::QuicheStringPiece(), | 
 |                           /*retry_without_tag=*/quiche::QuicheStringPiece()); | 
 |   return true; | 
 | } | 
 |  | 
 | // Seeks the current packet to check for a coalesced packet at the end. | 
 | // If the IETF length field only spans part of the outer packet, | 
 | // then there is a coalesced packet after this one. | 
 | void QuicFramer::MaybeProcessCoalescedPacket( | 
 |     const QuicDataReader& encrypted_reader, | 
 |     uint64_t remaining_bytes_length, | 
 |     const QuicPacketHeader& header) { | 
 |   if (header.remaining_packet_length >= remaining_bytes_length) { | 
 |     // There is no coalesced packet. | 
 |     return; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece remaining_data = | 
 |       encrypted_reader.PeekRemainingPayload(); | 
 |   DCHECK_EQ(remaining_data.length(), remaining_bytes_length); | 
 |  | 
 |   const char* coalesced_data = | 
 |       remaining_data.data() + header.remaining_packet_length; | 
 |   uint64_t coalesced_data_length = | 
 |       remaining_bytes_length - header.remaining_packet_length; | 
 |   QuicDataReader coalesced_reader(coalesced_data, coalesced_data_length); | 
 |  | 
 |   QuicPacketHeader coalesced_header; | 
 |   if (!ProcessIetfPacketHeader(&coalesced_reader, &coalesced_header)) { | 
 |     // Some implementations pad their INITIAL packets by sending random invalid | 
 |     // data after the INITIAL, and that is allowed by the specification. If we | 
 |     // fail to parse a subsequent coalesced packet, simply ignore it. | 
 |     QUIC_DLOG(INFO) << ENDPOINT | 
 |                     << "Failed to parse received coalesced header of length " | 
 |                     << coalesced_data_length | 
 |                     << " with error: " << detailed_error_ << ": " | 
 |                     << quiche::QuicheTextUtils::HexEncode(coalesced_data, | 
 |                                                           coalesced_data_length) | 
 |                     << " previous header was " << header; | 
 |     return; | 
 |   } | 
 |  | 
 |   if (coalesced_header.destination_connection_id != | 
 |       header.destination_connection_id) { | 
 |     // Drop coalesced packets with mismatched connection IDs. | 
 |     QUIC_DLOG(INFO) << ENDPOINT << "Received mismatched coalesced header " | 
 |                     << coalesced_header << " previous header was " << header; | 
 |     QUIC_CODE_COUNT( | 
 |         quic_received_coalesced_packets_with_mismatched_connection_id); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicEncryptedPacket coalesced_packet(coalesced_data, coalesced_data_length, | 
 |                                        /*owns_buffer=*/false); | 
 |   visitor_->OnCoalescedPacket(coalesced_packet); | 
 | } | 
 |  | 
 | bool QuicFramer::MaybeProcessIetfLength(QuicDataReader* encrypted_reader, | 
 |                                         QuicPacketHeader* header) { | 
 |   if (!QuicVersionHasLongHeaderLengths(header->version.transport_version) || | 
 |       header->form != IETF_QUIC_LONG_HEADER_PACKET || | 
 |       (header->long_packet_type != INITIAL && | 
 |        header->long_packet_type != HANDSHAKE && | 
 |        header->long_packet_type != ZERO_RTT_PROTECTED)) { | 
 |     return true; | 
 |   } | 
 |   header->length_length = encrypted_reader->PeekVarInt62Length(); | 
 |   if (!encrypted_reader->ReadVarInt62(&header->remaining_packet_length)) { | 
 |     set_detailed_error("Unable to read long header payload length."); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |   uint64_t remaining_bytes_length = encrypted_reader->BytesRemaining(); | 
 |   if (header->remaining_packet_length > remaining_bytes_length) { | 
 |     set_detailed_error("Long header payload length longer than packet."); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |  | 
 |   MaybeProcessCoalescedPacket(*encrypted_reader, remaining_bytes_length, | 
 |                               *header); | 
 |  | 
 |   if (!encrypted_reader->TruncateRemaining(header->remaining_packet_length)) { | 
 |     set_detailed_error("Length TruncateRemaining failed."); | 
 |     QUIC_BUG << "Length TruncateRemaining failed."; | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfDataPacket(QuicDataReader* encrypted_reader, | 
 |                                        QuicPacketHeader* header, | 
 |                                        const QuicEncryptedPacket& packet, | 
 |                                        char* decrypted_buffer, | 
 |                                        size_t buffer_length) { | 
 |   DCHECK_NE(GOOGLE_QUIC_PACKET, header->form); | 
 |   DCHECK(!header->has_possible_stateless_reset_token); | 
 |   header->length_length = VARIABLE_LENGTH_INTEGER_LENGTH_0; | 
 |   header->remaining_packet_length = 0; | 
 |   if (header->form == IETF_QUIC_SHORT_HEADER_PACKET && | 
 |       perspective_ == Perspective::IS_CLIENT) { | 
 |     // Peek possible stateless reset token. Will only be used on decryption | 
 |     // failure. | 
 |     quiche::QuicheStringPiece remaining = | 
 |         encrypted_reader->PeekRemainingPayload(); | 
 |     if (remaining.length() >= sizeof(header->possible_stateless_reset_token)) { | 
 |       header->has_possible_stateless_reset_token = true; | 
 |       memcpy(&header->possible_stateless_reset_token, | 
 |              &remaining.data()[remaining.length() - | 
 |                                sizeof(header->possible_stateless_reset_token)], | 
 |              sizeof(header->possible_stateless_reset_token)); | 
 |     } | 
 |   } | 
 |  | 
 |   if (!MaybeProcessIetfLength(encrypted_reader, header)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece associated_data; | 
 |   std::vector<char> ad_storage; | 
 |   if (header->form == IETF_QUIC_SHORT_HEADER_PACKET || | 
 |       header->long_packet_type != VERSION_NEGOTIATION) { | 
 |     DCHECK(header->form == IETF_QUIC_SHORT_HEADER_PACKET || | 
 |            header->long_packet_type == INITIAL || | 
 |            header->long_packet_type == HANDSHAKE || | 
 |            header->long_packet_type == ZERO_RTT_PROTECTED); | 
 |     // Process packet number. | 
 |     QuicPacketNumber base_packet_number; | 
 |     if (supports_multiple_packet_number_spaces_) { | 
 |       PacketNumberSpace pn_space = GetPacketNumberSpace(*header); | 
 |       if (pn_space == NUM_PACKET_NUMBER_SPACES) { | 
 |         return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |       } | 
 |       base_packet_number = largest_decrypted_packet_numbers_[pn_space]; | 
 |     } else { | 
 |       base_packet_number = largest_packet_number_; | 
 |     } | 
 |     uint64_t full_packet_number; | 
 |     bool hp_removal_failed = false; | 
 |     if (version_.HasHeaderProtection()) { | 
 |       if (!RemoveHeaderProtection(encrypted_reader, packet, header, | 
 |                                   &full_packet_number, &ad_storage)) { | 
 |         hp_removal_failed = true; | 
 |       } | 
 |       associated_data = | 
 |           quiche::QuicheStringPiece(ad_storage.data(), ad_storage.size()); | 
 |     } else if (!ProcessAndCalculatePacketNumber( | 
 |                    encrypted_reader, header->packet_number_length, | 
 |                    base_packet_number, &full_packet_number)) { | 
 |       set_detailed_error("Unable to read packet number."); | 
 |       RecordDroppedPacketReason(DroppedPacketReason::INVALID_PACKET_NUMBER); | 
 |       return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |     } | 
 |  | 
 |     if (hp_removal_failed || | 
 |         !IsValidFullPacketNumber(full_packet_number, version())) { | 
 |       if (IsIetfStatelessResetPacket(*header)) { | 
 |         // This is a stateless reset packet. | 
 |         QuicIetfStatelessResetPacket packet( | 
 |             *header, header->possible_stateless_reset_token); | 
 |         visitor_->OnAuthenticatedIetfStatelessResetPacket(packet); | 
 |         return true; | 
 |       } | 
 |       if (hp_removal_failed) { | 
 |         const EncryptionLevel decryption_level = GetEncryptionLevel(*header); | 
 |         const bool has_decryption_key = decrypter_[decryption_level] != nullptr; | 
 |         visitor_->OnUndecryptablePacket( | 
 |             QuicEncryptedPacket(encrypted_reader->FullPayload()), | 
 |             decryption_level, has_decryption_key); | 
 |         set_detailed_error(quiche::QuicheStrCat( | 
 |             "Unable to decrypt ", EncryptionLevelToString(decryption_level), | 
 |             " header protection", has_decryption_key ? "" : " (missing key)", | 
 |             ".")); | 
 |         return RaiseError(QUIC_DECRYPTION_FAILURE); | 
 |       } | 
 |       RecordDroppedPacketReason(DroppedPacketReason::INVALID_PACKET_NUMBER); | 
 |       set_detailed_error("packet numbers cannot be 0."); | 
 |       return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |     } | 
 |     header->packet_number = QuicPacketNumber(full_packet_number); | 
 |   } | 
 |  | 
 |   // A nonce should only present in SHLO from the server to the client when | 
 |   // using QUIC crypto. | 
 |   if (header->form == IETF_QUIC_LONG_HEADER_PACKET && | 
 |       header->long_packet_type == ZERO_RTT_PROTECTED && | 
 |       perspective_ == Perspective::IS_CLIENT && | 
 |       version_.handshake_protocol == PROTOCOL_QUIC_CRYPTO) { | 
 |     if (!encrypted_reader->ReadBytes( | 
 |             reinterpret_cast<uint8_t*>(last_nonce_.data()), | 
 |             last_nonce_.size())) { | 
 |       set_detailed_error("Unable to read nonce."); | 
 |       RecordDroppedPacketReason( | 
 |           DroppedPacketReason::INVALID_DIVERSIFICATION_NONCE); | 
 |       return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |     } | 
 |  | 
 |     header->nonce = &last_nonce_; | 
 |   } else { | 
 |     header->nonce = nullptr; | 
 |   } | 
 |  | 
 |   if (!visitor_->OnUnauthenticatedHeader(*header)) { | 
 |     set_detailed_error( | 
 |         "Visitor asked to stop processing of unauthenticated header."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece encrypted = | 
 |       encrypted_reader->ReadRemainingPayload(); | 
 |   if (!version_.HasHeaderProtection()) { | 
 |     associated_data = GetAssociatedDataFromEncryptedPacket( | 
 |         version_.transport_version, packet, | 
 |         GetIncludedDestinationConnectionIdLength(*header), | 
 |         GetIncludedSourceConnectionIdLength(*header), header->version_flag, | 
 |         header->nonce != nullptr, header->packet_number_length, | 
 |         header->retry_token_length_length, header->retry_token.length(), | 
 |         header->length_length); | 
 |   } | 
 |  | 
 |   size_t decrypted_length = 0; | 
 |   EncryptionLevel decrypted_level; | 
 |   if (!DecryptPayload(encrypted, associated_data, *header, decrypted_buffer, | 
 |                       buffer_length, &decrypted_length, &decrypted_level)) { | 
 |     if (IsIetfStatelessResetPacket(*header)) { | 
 |       // This is a stateless reset packet. | 
 |       QuicIetfStatelessResetPacket packet( | 
 |           *header, header->possible_stateless_reset_token); | 
 |       visitor_->OnAuthenticatedIetfStatelessResetPacket(packet); | 
 |       return true; | 
 |     } | 
 |     const EncryptionLevel decryption_level = GetEncryptionLevel(*header); | 
 |     const bool has_decryption_key = version_.KnowsWhichDecrypterToUse() && | 
 |                                     decrypter_[decryption_level] != nullptr; | 
 |     visitor_->OnUndecryptablePacket( | 
 |         QuicEncryptedPacket(encrypted_reader->FullPayload()), decryption_level, | 
 |         has_decryption_key); | 
 |     set_detailed_error(quiche::QuicheStrCat( | 
 |         "Unable to decrypt ", EncryptionLevelToString(decryption_level), | 
 |         " payload", | 
 |         has_decryption_key || !version_.KnowsWhichDecrypterToUse() | 
 |             ? "" | 
 |             : " (missing key)", | 
 |         ".")); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::DECRYPTION_FAILURE); | 
 |     return RaiseError(QUIC_DECRYPTION_FAILURE); | 
 |   } | 
 |   QuicDataReader reader(decrypted_buffer, decrypted_length); | 
 |  | 
 |   // Update the largest packet number after we have decrypted the packet | 
 |   // so we are confident is not attacker controlled. | 
 |   if (supports_multiple_packet_number_spaces_) { | 
 |     largest_decrypted_packet_numbers_[QuicUtils::GetPacketNumberSpace( | 
 |                                           decrypted_level)] | 
 |         .UpdateMax(header->packet_number); | 
 |   } else { | 
 |     largest_packet_number_.UpdateMax(header->packet_number); | 
 |   } | 
 |  | 
 |   if (!visitor_->OnPacketHeader(*header)) { | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PACKET_NUMBER); | 
 |     // The visitor suppresses further processing of the packet. | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (packet.length() > kMaxIncomingPacketSize) { | 
 |     set_detailed_error("Packet too large."); | 
 |     return RaiseError(QUIC_PACKET_TOO_LARGE); | 
 |   } | 
 |  | 
 |   // Handle the payload. | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     current_received_frame_type_ = 0; | 
 |     if (!ProcessIetfFrameData(&reader, *header)) { | 
 |       current_received_frame_type_ = 0; | 
 |       DCHECK_NE(QUIC_NO_ERROR, error_);  // ProcessIetfFrameData sets the error. | 
 |       DCHECK_NE("", detailed_error_); | 
 |       QUIC_DLOG(WARNING) << ENDPOINT << "Unable to process frame data. Error: " | 
 |                          << detailed_error_; | 
 |       return false; | 
 |     } | 
 |     current_received_frame_type_ = 0; | 
 |   } else { | 
 |     if (!ProcessFrameData(&reader, *header)) { | 
 |       DCHECK_NE(QUIC_NO_ERROR, error_);  // ProcessFrameData sets the error. | 
 |       DCHECK_NE("", detailed_error_); | 
 |       QUIC_DLOG(WARNING) << ENDPOINT << "Unable to process frame data. Error: " | 
 |                          << detailed_error_; | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   visitor_->OnPacketComplete(); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessDataPacket(QuicDataReader* encrypted_reader, | 
 |                                    QuicPacketHeader* header, | 
 |                                    const QuicEncryptedPacket& packet, | 
 |                                    char* decrypted_buffer, | 
 |                                    size_t buffer_length) { | 
 |   if (!ProcessUnauthenticatedHeader(encrypted_reader, header)) { | 
 |     DCHECK_NE("", detailed_error_); | 
 |     QUIC_DVLOG(1) | 
 |         << ENDPOINT | 
 |         << "Unable to process packet header. Stopping parsing. Error: " | 
 |         << detailed_error_; | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PACKET_NUMBER); | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece encrypted = | 
 |       encrypted_reader->ReadRemainingPayload(); | 
 |   quiche::QuicheStringPiece associated_data = | 
 |       GetAssociatedDataFromEncryptedPacket( | 
 |           version_.transport_version, packet, | 
 |           GetIncludedDestinationConnectionIdLength(*header), | 
 |           GetIncludedSourceConnectionIdLength(*header), header->version_flag, | 
 |           header->nonce != nullptr, header->packet_number_length, | 
 |           header->retry_token_length_length, header->retry_token.length(), | 
 |           header->length_length); | 
 |  | 
 |   size_t decrypted_length = 0; | 
 |   EncryptionLevel decrypted_level; | 
 |   if (!DecryptPayload(encrypted, associated_data, *header, decrypted_buffer, | 
 |                       buffer_length, &decrypted_length, &decrypted_level)) { | 
 |     const EncryptionLevel decryption_level = decrypter_level_; | 
 |     // This version uses trial decryption so we always report to our visitor | 
 |     // that we are not certain we have the correct decryption key. | 
 |     const bool has_decryption_key = false; | 
 |     visitor_->OnUndecryptablePacket( | 
 |         QuicEncryptedPacket(encrypted_reader->FullPayload()), decryption_level, | 
 |         has_decryption_key); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::DECRYPTION_FAILURE); | 
 |     set_detailed_error(quiche::QuicheStrCat( | 
 |         "Unable to decrypt ", EncryptionLevelToString(decryption_level), | 
 |         " payload.")); | 
 |     return RaiseError(QUIC_DECRYPTION_FAILURE); | 
 |   } | 
 |  | 
 |   QuicDataReader reader(decrypted_buffer, decrypted_length); | 
 |  | 
 |   // Update the largest packet number after we have decrypted the packet | 
 |   // so we are confident is not attacker controlled. | 
 |   if (supports_multiple_packet_number_spaces_) { | 
 |     largest_decrypted_packet_numbers_[QuicUtils::GetPacketNumberSpace( | 
 |                                           decrypted_level)] | 
 |         .UpdateMax(header->packet_number); | 
 |   } else { | 
 |     largest_packet_number_.UpdateMax(header->packet_number); | 
 |   } | 
 |  | 
 |   if (!visitor_->OnPacketHeader(*header)) { | 
 |     // The visitor suppresses further processing of the packet. | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (packet.length() > kMaxIncomingPacketSize) { | 
 |     set_detailed_error("Packet too large."); | 
 |     return RaiseError(QUIC_PACKET_TOO_LARGE); | 
 |   } | 
 |  | 
 |   // Handle the payload. | 
 |   if (!ProcessFrameData(&reader, *header)) { | 
 |     DCHECK_NE(QUIC_NO_ERROR, error_);  // ProcessFrameData sets the error. | 
 |     DCHECK_NE("", detailed_error_); | 
 |     QUIC_DLOG(WARNING) << ENDPOINT << "Unable to process frame data. Error: " | 
 |                        << detailed_error_; | 
 |     return false; | 
 |   } | 
 |  | 
 |   visitor_->OnPacketComplete(); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessPublicResetPacket(QuicDataReader* reader, | 
 |                                           const QuicPacketHeader& header) { | 
 |   QuicPublicResetPacket packet( | 
 |       GetServerConnectionIdAsRecipient(header, perspective_)); | 
 |  | 
 |   std::unique_ptr<CryptoHandshakeMessage> reset( | 
 |       CryptoFramer::ParseMessage(reader->ReadRemainingPayload())); | 
 |   if (!reset) { | 
 |     set_detailed_error("Unable to read reset message."); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PUBLIC_RESET_PACKET); | 
 |     return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET); | 
 |   } | 
 |   if (reset->tag() != kPRST) { | 
 |     set_detailed_error("Incorrect message tag."); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PUBLIC_RESET_PACKET); | 
 |     return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET); | 
 |   } | 
 |  | 
 |   if (reset->GetUint64(kRNON, &packet.nonce_proof) != QUIC_NO_ERROR) { | 
 |     set_detailed_error("Unable to read nonce proof."); | 
 |     RecordDroppedPacketReason(DroppedPacketReason::INVALID_PUBLIC_RESET_PACKET); | 
 |     return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET); | 
 |   } | 
 |   // TODO(satyamshekhar): validate nonce to protect against DoS. | 
 |  | 
 |   quiche::QuicheStringPiece address; | 
 |   if (reset->GetStringPiece(kCADR, &address)) { | 
 |     QuicSocketAddressCoder address_coder; | 
 |     if (address_coder.Decode(address.data(), address.length())) { | 
 |       packet.client_address = | 
 |           QuicSocketAddress(address_coder.ip(), address_coder.port()); | 
 |     } | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece endpoint_id; | 
 |   if (perspective_ == Perspective::IS_CLIENT && | 
 |       reset->GetStringPiece(kEPID, &endpoint_id)) { | 
 |     packet.endpoint_id = std::string(endpoint_id); | 
 |     packet.endpoint_id += '\0'; | 
 |   } | 
 |  | 
 |   visitor_->OnPublicResetPacket(packet); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::IsIetfStatelessResetPacket( | 
 |     const QuicPacketHeader& header) const { | 
 |   QUIC_BUG_IF(header.has_possible_stateless_reset_token && | 
 |               perspective_ != Perspective::IS_CLIENT) | 
 |       << "has_possible_stateless_reset_token can only be true at client side."; | 
 |   return header.form == IETF_QUIC_SHORT_HEADER_PACKET && | 
 |          header.has_possible_stateless_reset_token && | 
 |          visitor_->IsValidStatelessResetToken( | 
 |              header.possible_stateless_reset_token); | 
 | } | 
 |  | 
 | bool QuicFramer::HasEncrypterOfEncryptionLevel(EncryptionLevel level) const { | 
 |   return encrypter_[level] != nullptr; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendPacketHeader(const QuicPacketHeader& header, | 
 |                                     QuicDataWriter* writer, | 
 |                                     size_t* length_field_offset) { | 
 |   if (VersionHasIetfInvariantHeader(transport_version())) { | 
 |     return AppendIetfPacketHeader(header, writer, length_field_offset); | 
 |   } | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Appending header: " << header; | 
 |   uint8_t public_flags = 0; | 
 |   if (header.reset_flag) { | 
 |     public_flags |= PACKET_PUBLIC_FLAGS_RST; | 
 |   } | 
 |   if (header.version_flag) { | 
 |     public_flags |= PACKET_PUBLIC_FLAGS_VERSION; | 
 |   } | 
 |  | 
 |   public_flags |= GetPacketNumberFlags(header.packet_number_length) | 
 |                   << kPublicHeaderSequenceNumberShift; | 
 |  | 
 |   if (header.nonce != nullptr) { | 
 |     DCHECK_EQ(Perspective::IS_SERVER, perspective_); | 
 |     public_flags |= PACKET_PUBLIC_FLAGS_NONCE; | 
 |   } | 
 |  | 
 |   QuicConnectionId server_connection_id = | 
 |       GetServerConnectionIdAsSender(header, perspective_); | 
 |   QuicConnectionIdIncluded server_connection_id_included = | 
 |       GetServerConnectionIdIncludedAsSender(header, perspective_); | 
 |   DCHECK_EQ(CONNECTION_ID_ABSENT, | 
 |             GetClientConnectionIdIncludedAsSender(header, perspective_)) | 
 |       << ENDPOINT << ParsedQuicVersionToString(version_) | 
 |       << " invalid header: " << header; | 
 |  | 
 |   switch (server_connection_id_included) { | 
 |     case CONNECTION_ID_ABSENT: | 
 |       if (!writer->WriteUInt8(public_flags | | 
 |                               PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID)) { | 
 |         return false; | 
 |       } | 
 |       break; | 
 |     case CONNECTION_ID_PRESENT: | 
 |       QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion( | 
 |           server_connection_id, transport_version())) | 
 |           << "AppendPacketHeader: attempted to use connection ID " | 
 |           << server_connection_id << " which is invalid with version " | 
 |           << QuicVersionToString(transport_version()); | 
 |  | 
 |       public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID; | 
 |       if (perspective_ == Perspective::IS_CLIENT) { | 
 |         public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD; | 
 |       } | 
 |       if (!writer->WriteUInt8(public_flags) || | 
 |           !writer->WriteConnectionId(server_connection_id)) { | 
 |         return false; | 
 |       } | 
 |       break; | 
 |   } | 
 |   last_serialized_server_connection_id_ = server_connection_id; | 
 |  | 
 |   if (header.version_flag) { | 
 |     DCHECK_EQ(Perspective::IS_CLIENT, perspective_); | 
 |     QuicVersionLabel version_label = CreateQuicVersionLabel(version_); | 
 |     if (!writer->WriteUInt32(version_label)) { | 
 |       return false; | 
 |     } | 
 |  | 
 |     QUIC_DVLOG(1) << ENDPOINT << "label = '" | 
 |                   << QuicVersionLabelToString(version_label) << "'"; | 
 |   } | 
 |  | 
 |   if (header.nonce != nullptr && | 
 |       !writer->WriteBytes(header.nonce, kDiversificationNonceSize)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!AppendPacketNumber(header.packet_number_length, header.packet_number, | 
 |                           writer)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendIetfHeaderTypeByte(const QuicPacketHeader& header, | 
 |                                           QuicDataWriter* writer) { | 
 |   uint8_t type = 0; | 
 |   if (header.version_flag) { | 
 |     type = static_cast<uint8_t>( | 
 |         FLAGS_LONG_HEADER | FLAGS_FIXED_BIT | | 
 |         LongHeaderTypeToOnWireValue(header.long_packet_type) | | 
 |         PacketNumberLengthToOnWireValue(header.packet_number_length)); | 
 |   } else { | 
 |     type = static_cast<uint8_t>( | 
 |         FLAGS_FIXED_BIT | | 
 |         PacketNumberLengthToOnWireValue(header.packet_number_length)); | 
 |   } | 
 |   return writer->WriteUInt8(type); | 
 | } | 
 |  | 
 | bool QuicFramer::AppendIetfPacketHeader(const QuicPacketHeader& header, | 
 |                                         QuicDataWriter* writer, | 
 |                                         size_t* length_field_offset) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Appending IETF header: " << header; | 
 |   QuicConnectionId server_connection_id = | 
 |       GetServerConnectionIdAsSender(header, perspective_); | 
 |   QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion(server_connection_id, | 
 |                                                         transport_version())) | 
 |       << "AppendIetfPacketHeader: attempted to use connection ID " | 
 |       << server_connection_id << " which is invalid with version " | 
 |       << QuicVersionToString(transport_version()); | 
 |   if (!AppendIetfHeaderTypeByte(header, writer)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (header.version_flag) { | 
 |     DCHECK_NE(VERSION_NEGOTIATION, header.long_packet_type) | 
 |         << "QuicFramer::AppendIetfPacketHeader does not support sending " | 
 |            "version negotiation packets, use " | 
 |            "QuicFramer::BuildVersionNegotiationPacket instead " | 
 |         << header; | 
 |     // Append version for long header. | 
 |     QuicVersionLabel version_label = CreateQuicVersionLabel(version_); | 
 |     if (!writer->WriteUInt32(version_label)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   // Append connection ID. | 
 |   if (!AppendIetfConnectionIds( | 
 |           header.version_flag, version_.HasLengthPrefixedConnectionIds(), | 
 |           header.destination_connection_id_included != CONNECTION_ID_ABSENT | 
 |               ? header.destination_connection_id | 
 |               : EmptyQuicConnectionId(), | 
 |           header.source_connection_id_included != CONNECTION_ID_ABSENT | 
 |               ? header.source_connection_id | 
 |               : EmptyQuicConnectionId(), | 
 |           writer)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   last_serialized_server_connection_id_ = server_connection_id; | 
 |   if (version_.SupportsClientConnectionIds()) { | 
 |     last_serialized_client_connection_id_ = | 
 |         GetClientConnectionIdAsSender(header, perspective_); | 
 |   } | 
 |  | 
 |   // TODO(b/141924462) Remove this QUIC_BUG once we do support sending RETRY. | 
 |   QUIC_BUG_IF(header.version_flag && header.long_packet_type == RETRY) | 
 |       << "Sending IETF RETRY packets is not currently supported " << header; | 
 |  | 
 |   if (QuicVersionHasLongHeaderLengths(transport_version()) && | 
 |       header.version_flag) { | 
 |     if (header.long_packet_type == INITIAL) { | 
 |       DCHECK_NE(VARIABLE_LENGTH_INTEGER_LENGTH_0, | 
 |                 header.retry_token_length_length) | 
 |           << ENDPOINT << ParsedQuicVersionToString(version_) | 
 |           << " bad retry token length length in header: " << header; | 
 |       // Write retry token length. | 
 |       if (!writer->WriteVarInt62(header.retry_token.length(), | 
 |                                  header.retry_token_length_length)) { | 
 |         return false; | 
 |       } | 
 |       // Write retry token. | 
 |       if (!header.retry_token.empty() && | 
 |           !writer->WriteStringPiece(header.retry_token)) { | 
 |         return false; | 
 |       } | 
 |     } | 
 |     if (length_field_offset != nullptr) { | 
 |       *length_field_offset = writer->length(); | 
 |     } | 
 |     // Add fake length to reserve two bytes to add length in later. | 
 |     writer->WriteVarInt62(256); | 
 |   } else if (length_field_offset != nullptr) { | 
 |     *length_field_offset = 0; | 
 |   } | 
 |  | 
 |   // Append packet number. | 
 |   if (!AppendPacketNumber(header.packet_number_length, header.packet_number, | 
 |                           writer)) { | 
 |     return false; | 
 |   } | 
 |   last_written_packet_number_length_ = header.packet_number_length; | 
 |  | 
 |   if (!header.version_flag) { | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (header.nonce != nullptr) { | 
 |     DCHECK(header.version_flag); | 
 |     DCHECK_EQ(ZERO_RTT_PROTECTED, header.long_packet_type); | 
 |     DCHECK_EQ(Perspective::IS_SERVER, perspective_); | 
 |     if (!writer->WriteBytes(header.nonce, kDiversificationNonceSize)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | const QuicTime::Delta QuicFramer::CalculateTimestampFromWire( | 
 |     uint32_t time_delta_us) { | 
 |   // The new time_delta might have wrapped to the next epoch, or it | 
 |   // might have reverse wrapped to the previous epoch, or it might | 
 |   // remain in the same epoch. Select the time closest to the previous | 
 |   // time. | 
 |   // | 
 |   // epoch_delta is the delta between epochs. A delta is 4 bytes of | 
 |   // microseconds. | 
 |   const uint64_t epoch_delta = UINT64_C(1) << 32; | 
 |   uint64_t epoch = last_timestamp_.ToMicroseconds() & ~(epoch_delta - 1); | 
 |   // Wrapping is safe here because a wrapped value will not be ClosestTo below. | 
 |   uint64_t prev_epoch = epoch - epoch_delta; | 
 |   uint64_t next_epoch = epoch + epoch_delta; | 
 |  | 
 |   uint64_t time = ClosestTo( | 
 |       last_timestamp_.ToMicroseconds(), epoch + time_delta_us, | 
 |       ClosestTo(last_timestamp_.ToMicroseconds(), prev_epoch + time_delta_us, | 
 |                 next_epoch + time_delta_us)); | 
 |  | 
 |   return QuicTime::Delta::FromMicroseconds(time); | 
 | } | 
 |  | 
 | uint64_t QuicFramer::CalculatePacketNumberFromWire( | 
 |     QuicPacketNumberLength packet_number_length, | 
 |     QuicPacketNumber base_packet_number, | 
 |     uint64_t packet_number) const { | 
 |   // The new packet number might have wrapped to the next epoch, or | 
 |   // it might have reverse wrapped to the previous epoch, or it might | 
 |   // remain in the same epoch.  Select the packet number closest to the | 
 |   // next expected packet number, the previous packet number plus 1. | 
 |  | 
 |   // epoch_delta is the delta between epochs the packet number was serialized | 
 |   // with, so the correct value is likely the same epoch as the last sequence | 
 |   // number or an adjacent epoch. | 
 |   if (!base_packet_number.IsInitialized()) { | 
 |     return packet_number; | 
 |   } | 
 |   const uint64_t epoch_delta = UINT64_C(1) << (8 * packet_number_length); | 
 |   uint64_t next_packet_number = base_packet_number.ToUint64() + 1; | 
 |   uint64_t epoch = base_packet_number.ToUint64() & ~(epoch_delta - 1); | 
 |   uint64_t prev_epoch = epoch - epoch_delta; | 
 |   uint64_t next_epoch = epoch + epoch_delta; | 
 |  | 
 |   return ClosestTo(next_packet_number, epoch + packet_number, | 
 |                    ClosestTo(next_packet_number, prev_epoch + packet_number, | 
 |                              next_epoch + packet_number)); | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessPublicHeader(QuicDataReader* reader, | 
 |                                      bool packet_has_ietf_packet_header, | 
 |                                      QuicPacketHeader* header) { | 
 |   if (packet_has_ietf_packet_header) { | 
 |     return ProcessIetfPacketHeader(reader, header); | 
 |   } | 
 |   uint8_t public_flags; | 
 |   if (!reader->ReadBytes(&public_flags, 1)) { | 
 |     set_detailed_error("Unable to read public flags."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   header->reset_flag = (public_flags & PACKET_PUBLIC_FLAGS_RST) != 0; | 
 |   header->version_flag = (public_flags & PACKET_PUBLIC_FLAGS_VERSION) != 0; | 
 |  | 
 |   if (validate_flags_ && !header->version_flag && | 
 |       public_flags > PACKET_PUBLIC_FLAGS_MAX) { | 
 |     set_detailed_error("Illegal public flags value."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (header->reset_flag && header->version_flag) { | 
 |     set_detailed_error("Got version flag in reset packet"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicConnectionId* header_connection_id = &header->destination_connection_id; | 
 |   QuicConnectionIdIncluded* header_connection_id_included = | 
 |       &header->destination_connection_id_included; | 
 |   if (perspective_ == Perspective::IS_CLIENT) { | 
 |     header_connection_id = &header->source_connection_id; | 
 |     header_connection_id_included = &header->source_connection_id_included; | 
 |   } | 
 |   switch (public_flags & PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID) { | 
 |     case PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID: | 
 |       if (!reader->ReadConnectionId(header_connection_id, | 
 |                                     kQuicDefaultConnectionIdLength)) { | 
 |         set_detailed_error("Unable to read ConnectionId."); | 
 |         return false; | 
 |       } | 
 |       *header_connection_id_included = CONNECTION_ID_PRESENT; | 
 |       break; | 
 |     case PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID: | 
 |       *header_connection_id_included = CONNECTION_ID_ABSENT; | 
 |       *header_connection_id = last_serialized_server_connection_id_; | 
 |       break; | 
 |   } | 
 |  | 
 |   header->packet_number_length = ReadSequenceNumberLength( | 
 |       public_flags >> kPublicHeaderSequenceNumberShift); | 
 |  | 
 |   // Read the version only if the packet is from the client. | 
 |   // version flag from the server means version negotiation packet. | 
 |   if (header->version_flag && perspective_ == Perspective::IS_SERVER) { | 
 |     QuicVersionLabel version_label; | 
 |     if (!ProcessVersionLabel(reader, &version_label)) { | 
 |       set_detailed_error("Unable to read protocol version."); | 
 |       return false; | 
 |     } | 
 |     // If the version from the new packet is the same as the version of this | 
 |     // framer, then the public flags should be set to something we understand. | 
 |     // If not, this raises an error. | 
 |     ParsedQuicVersion version = ParseQuicVersionLabel(version_label); | 
 |     if (version == version_ && public_flags > PACKET_PUBLIC_FLAGS_MAX) { | 
 |       set_detailed_error("Illegal public flags value."); | 
 |       return false; | 
 |     } | 
 |     header->version = version; | 
 |   } | 
 |  | 
 |   // A nonce should only be present in packets from the server to the client, | 
 |   // which are neither version negotiation nor public reset packets. | 
 |   if (public_flags & PACKET_PUBLIC_FLAGS_NONCE && | 
 |       !(public_flags & PACKET_PUBLIC_FLAGS_VERSION) && | 
 |       !(public_flags & PACKET_PUBLIC_FLAGS_RST) && | 
 |       // The nonce flag from a client is ignored and is assumed to be an older | 
 |       // client indicating an eight-byte connection ID. | 
 |       perspective_ == Perspective::IS_CLIENT) { | 
 |     if (!reader->ReadBytes(reinterpret_cast<uint8_t*>(last_nonce_.data()), | 
 |                            last_nonce_.size())) { | 
 |       set_detailed_error("Unable to read nonce."); | 
 |       return false; | 
 |     } | 
 |     header->nonce = &last_nonce_; | 
 |   } else { | 
 |     header->nonce = nullptr; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | // static | 
 | QuicPacketNumberLength QuicFramer::GetMinPacketNumberLength( | 
 |     QuicPacketNumber packet_number) { | 
 |   DCHECK(packet_number.IsInitialized()); | 
 |   if (packet_number < QuicPacketNumber(1 << (PACKET_1BYTE_PACKET_NUMBER * 8))) { | 
 |     return PACKET_1BYTE_PACKET_NUMBER; | 
 |   } else if (packet_number < | 
 |              QuicPacketNumber(1 << (PACKET_2BYTE_PACKET_NUMBER * 8))) { | 
 |     return PACKET_2BYTE_PACKET_NUMBER; | 
 |   } else if (packet_number < | 
 |              QuicPacketNumber(UINT64_C(1) | 
 |                               << (PACKET_4BYTE_PACKET_NUMBER * 8))) { | 
 |     return PACKET_4BYTE_PACKET_NUMBER; | 
 |   } else { | 
 |     return PACKET_6BYTE_PACKET_NUMBER; | 
 |   } | 
 | } | 
 |  | 
 | // static | 
 | uint8_t QuicFramer::GetPacketNumberFlags( | 
 |     QuicPacketNumberLength packet_number_length) { | 
 |   switch (packet_number_length) { | 
 |     case PACKET_1BYTE_PACKET_NUMBER: | 
 |       return PACKET_FLAGS_1BYTE_PACKET; | 
 |     case PACKET_2BYTE_PACKET_NUMBER: | 
 |       return PACKET_FLAGS_2BYTE_PACKET; | 
 |     case PACKET_4BYTE_PACKET_NUMBER: | 
 |       return PACKET_FLAGS_4BYTE_PACKET; | 
 |     case PACKET_6BYTE_PACKET_NUMBER: | 
 |     case PACKET_8BYTE_PACKET_NUMBER: | 
 |       return PACKET_FLAGS_8BYTE_PACKET; | 
 |     default: | 
 |       QUIC_BUG << "Unreachable case statement."; | 
 |       return PACKET_FLAGS_8BYTE_PACKET; | 
 |   } | 
 | } | 
 |  | 
 | // static | 
 | QuicFramer::AckFrameInfo QuicFramer::GetAckFrameInfo( | 
 |     const QuicAckFrame& frame) { | 
 |   AckFrameInfo new_ack_info; | 
 |   if (frame.packets.Empty()) { | 
 |     return new_ack_info; | 
 |   } | 
 |   // The first block is the last interval. It isn't encoded with the gap-length | 
 |   // encoding, so skip it. | 
 |   new_ack_info.first_block_length = frame.packets.LastIntervalLength(); | 
 |   auto itr = frame.packets.rbegin(); | 
 |   QuicPacketNumber previous_start = itr->min(); | 
 |   new_ack_info.max_block_length = itr->Length(); | 
 |   ++itr; | 
 |  | 
 |   // Don't do any more work after getting information for 256 ACK blocks; any | 
 |   // more can't be encoded anyway. | 
 |   for (; itr != frame.packets.rend() && | 
 |          new_ack_info.num_ack_blocks < std::numeric_limits<uint8_t>::max(); | 
 |        previous_start = itr->min(), ++itr) { | 
 |     const auto& interval = *itr; | 
 |     const QuicPacketCount total_gap = previous_start - interval.max(); | 
 |     new_ack_info.num_ack_blocks += | 
 |         (total_gap + std::numeric_limits<uint8_t>::max() - 1) / | 
 |         std::numeric_limits<uint8_t>::max(); | 
 |     new_ack_info.max_block_length = | 
 |         std::max(new_ack_info.max_block_length, interval.Length()); | 
 |   } | 
 |   return new_ack_info; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessUnauthenticatedHeader(QuicDataReader* encrypted_reader, | 
 |                                               QuicPacketHeader* header) { | 
 |   QuicPacketNumber base_packet_number; | 
 |   if (supports_multiple_packet_number_spaces_) { | 
 |     PacketNumberSpace pn_space = GetPacketNumberSpace(*header); | 
 |     if (pn_space == NUM_PACKET_NUMBER_SPACES) { | 
 |       set_detailed_error("Unable to determine packet number space."); | 
 |       return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |     } | 
 |     base_packet_number = largest_decrypted_packet_numbers_[pn_space]; | 
 |   } else { | 
 |     base_packet_number = largest_packet_number_; | 
 |   } | 
 |   uint64_t full_packet_number; | 
 |   if (!ProcessAndCalculatePacketNumber( | 
 |           encrypted_reader, header->packet_number_length, base_packet_number, | 
 |           &full_packet_number)) { | 
 |     set_detailed_error("Unable to read packet number."); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |  | 
 |   if (!IsValidFullPacketNumber(full_packet_number, version())) { | 
 |     set_detailed_error("packet numbers cannot be 0."); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |   header->packet_number = QuicPacketNumber(full_packet_number); | 
 |  | 
 |   if (!visitor_->OnUnauthenticatedHeader(*header)) { | 
 |     set_detailed_error( | 
 |         "Visitor asked to stop processing of unauthenticated header."); | 
 |     return false; | 
 |   } | 
 |   // The function we are in is called because the framer believes that it is | 
 |   // processing a packet that uses the non-IETF (i.e. Google QUIC) packet header | 
 |   // type. Usually, the framer makes that decision based on the framer's | 
 |   // version, but when the framer is used with Perspective::IS_SERVER, then | 
 |   // before version negotiation is complete (specifically, before | 
 |   // InferPacketHeaderTypeFromVersion is called), this decision is made based on | 
 |   // the type byte of the packet. | 
 |   // | 
 |   // If the framer's version KnowsWhichDecrypterToUse, then that version expects | 
 |   // to use the IETF packet header type. If that's the case and we're in this | 
 |   // function, then the packet received is invalid: the framer was expecting an | 
 |   // IETF packet header and didn't get one. | 
 |   if (version().KnowsWhichDecrypterToUse()) { | 
 |     set_detailed_error("Invalid public header type for expected version."); | 
 |     return RaiseError(QUIC_INVALID_PACKET_HEADER); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfHeaderTypeByte(QuicDataReader* reader, | 
 |                                            QuicPacketHeader* header) { | 
 |   uint8_t type; | 
 |   if (!reader->ReadBytes(&type, 1)) { | 
 |     set_detailed_error("Unable to read first byte."); | 
 |     return false; | 
 |   } | 
 |   header->type_byte = type; | 
 |   // Determine whether this is a long or short header. | 
 |   header->form = GetIetfPacketHeaderFormat(type); | 
 |   if (header->form == IETF_QUIC_LONG_HEADER_PACKET) { | 
 |     // Version is always present in long headers. | 
 |     header->version_flag = true; | 
 |     // In versions that do not support client connection IDs, we mark the | 
 |     // corresponding connection ID as absent. | 
 |     header->destination_connection_id_included = | 
 |         (perspective_ == Perspective::IS_SERVER || | 
 |          version_.SupportsClientConnectionIds()) | 
 |             ? CONNECTION_ID_PRESENT | 
 |             : CONNECTION_ID_ABSENT; | 
 |     header->source_connection_id_included = | 
 |         (perspective_ == Perspective::IS_CLIENT || | 
 |          version_.SupportsClientConnectionIds()) | 
 |             ? CONNECTION_ID_PRESENT | 
 |             : CONNECTION_ID_ABSENT; | 
 |     // Read version tag. | 
 |     QuicVersionLabel version_label; | 
 |     if (!ProcessVersionLabel(reader, &version_label)) { | 
 |       set_detailed_error("Unable to read protocol version."); | 
 |       return false; | 
 |     } | 
 |     if (!version_label) { | 
 |       // Version label is 0 indicating this is a version negotiation packet. | 
 |       header->long_packet_type = VERSION_NEGOTIATION; | 
 |     } else { | 
 |       header->version = ParseQuicVersionLabel(version_label); | 
 |       if (header->version.transport_version != QUIC_VERSION_UNSUPPORTED) { | 
 |         if (!(type & FLAGS_FIXED_BIT)) { | 
 |           set_detailed_error("Fixed bit is 0 in long header."); | 
 |           return false; | 
 |         } | 
 |         if (!GetLongHeaderType(type, &header->long_packet_type)) { | 
 |           set_detailed_error("Illegal long header type value."); | 
 |           return false; | 
 |         } | 
 |         if (header->long_packet_type == RETRY) { | 
 |           if (!version().SupportsRetry()) { | 
 |             set_detailed_error("RETRY not supported in this version."); | 
 |             return false; | 
 |           } | 
 |           if (perspective_ == Perspective::IS_SERVER) { | 
 |             set_detailed_error("Client-initiated RETRY is invalid."); | 
 |             return false; | 
 |           } | 
 |         } else if (!header->version.HasHeaderProtection()) { | 
 |           header->packet_number_length = GetLongHeaderPacketNumberLength(type); | 
 |         } | 
 |       } | 
 |     } | 
 |  | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Received IETF long header: " | 
 |                   << QuicUtils::QuicLongHeaderTypetoString( | 
 |                          header->long_packet_type); | 
 |     return true; | 
 |   } | 
 |  | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Received IETF short header"; | 
 |   // Version is not present in short headers. | 
 |   header->version_flag = false; | 
 |   // In versions that do not support client connection IDs, the client will not | 
 |   // receive destination connection IDs. | 
 |   header->destination_connection_id_included = | 
 |       (perspective_ == Perspective::IS_SERVER || | 
 |        version_.SupportsClientConnectionIds()) | 
 |           ? CONNECTION_ID_PRESENT | 
 |           : CONNECTION_ID_ABSENT; | 
 |   header->source_connection_id_included = CONNECTION_ID_ABSENT; | 
 |   if (!(type & FLAGS_FIXED_BIT)) { | 
 |     set_detailed_error("Fixed bit is 0 in short header."); | 
 |     return false; | 
 |   } | 
 |   if (!version_.HasHeaderProtection()) { | 
 |     header->packet_number_length = GetShortHeaderPacketNumberLength(type); | 
 |   } | 
 |   QUIC_DVLOG(1) << "packet_number_length = " << header->packet_number_length; | 
 |   return true; | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::ProcessVersionLabel(QuicDataReader* reader, | 
 |                                      QuicVersionLabel* version_label) { | 
 |   if (!reader->ReadUInt32(version_label)) { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::ProcessAndValidateIetfConnectionIdLength( | 
 |     QuicDataReader* reader, | 
 |     ParsedQuicVersion version, | 
 |     Perspective perspective, | 
 |     bool should_update_expected_server_connection_id_length, | 
 |     uint8_t* expected_server_connection_id_length, | 
 |     uint8_t* destination_connection_id_length, | 
 |     uint8_t* source_connection_id_length, | 
 |     std::string* detailed_error) { | 
 |   uint8_t connection_id_lengths_byte; | 
 |   if (!reader->ReadBytes(&connection_id_lengths_byte, 1)) { | 
 |     *detailed_error = "Unable to read ConnectionId length."; | 
 |     return false; | 
 |   } | 
 |   uint8_t dcil = | 
 |       (connection_id_lengths_byte & kDestinationConnectionIdLengthMask) >> 4; | 
 |   if (dcil != 0) { | 
 |     dcil += kConnectionIdLengthAdjustment; | 
 |   } | 
 |   uint8_t scil = connection_id_lengths_byte & kSourceConnectionIdLengthMask; | 
 |   if (scil != 0) { | 
 |     scil += kConnectionIdLengthAdjustment; | 
 |   } | 
 |   if (should_update_expected_server_connection_id_length) { | 
 |     uint8_t server_connection_id_length = | 
 |         perspective == Perspective::IS_SERVER ? dcil : scil; | 
 |     if (*expected_server_connection_id_length != server_connection_id_length) { | 
 |       QUIC_DVLOG(1) << "Updating expected_server_connection_id_length: " | 
 |                     << static_cast<int>(*expected_server_connection_id_length) | 
 |                     << " -> " << static_cast<int>(server_connection_id_length); | 
 |       *expected_server_connection_id_length = server_connection_id_length; | 
 |     } | 
 |   } | 
 |   if (!should_update_expected_server_connection_id_length && | 
 |       (dcil != *destination_connection_id_length || | 
 |        scil != *source_connection_id_length) && | 
 |       version.IsKnown() && !version.AllowsVariableLengthConnectionIds()) { | 
 |     QUIC_DVLOG(1) << "dcil: " << static_cast<uint32_t>(dcil) | 
 |                   << ", scil: " << static_cast<uint32_t>(scil); | 
 |     *detailed_error = "Invalid ConnectionId length."; | 
 |     return false; | 
 |   } | 
 |   *destination_connection_id_length = dcil; | 
 |   *source_connection_id_length = scil; | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ValidateReceivedConnectionIds(const QuicPacketHeader& header) { | 
 |   if (!QuicUtils::IsConnectionIdValidForVersion( | 
 |           GetServerConnectionIdAsRecipient(header, perspective_), | 
 |           transport_version())) { | 
 |     set_detailed_error("Received server connection ID with invalid length."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (version_.SupportsClientConnectionIds() && | 
 |       !QuicUtils::IsConnectionIdValidForVersion( | 
 |           GetClientConnectionIdAsRecipient(header, perspective_), | 
 |           transport_version())) { | 
 |     set_detailed_error("Received client connection ID with invalid length."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfPacketHeader(QuicDataReader* reader, | 
 |                                          QuicPacketHeader* header) { | 
 |   if (version_.HasLengthPrefixedConnectionIds()) { | 
 |     uint8_t expected_destination_connection_id_length = | 
 |         perspective_ == Perspective::IS_CLIENT | 
 |             ? expected_client_connection_id_length_ | 
 |             : expected_server_connection_id_length_; | 
 |     QuicVersionLabel version_label; | 
 |     bool has_length_prefix; | 
 |     std::string detailed_error; | 
 |     QuicErrorCode parse_result = QuicFramer::ParsePublicHeader( | 
 |         reader, expected_destination_connection_id_length, | 
 |         VersionHasIetfInvariantHeader(version_.transport_version), | 
 |         &header->type_byte, &header->form, &header->version_flag, | 
 |         &has_length_prefix, &version_label, &header->version, | 
 |         &header->destination_connection_id, &header->source_connection_id, | 
 |         &header->long_packet_type, &header->retry_token_length_length, | 
 |         &header->retry_token, &detailed_error); | 
 |     if (parse_result != QUIC_NO_ERROR) { | 
 |       set_detailed_error(detailed_error); | 
 |       return false; | 
 |     } | 
 |     header->destination_connection_id_included = CONNECTION_ID_PRESENT; | 
 |     header->source_connection_id_included = | 
 |         header->version_flag ? CONNECTION_ID_PRESENT : CONNECTION_ID_ABSENT; | 
 |     if (header->source_connection_id_included == CONNECTION_ID_ABSENT) { | 
 |       DCHECK(header->source_connection_id.IsEmpty()); | 
 |       if (perspective_ == Perspective::IS_CLIENT) { | 
 |         header->source_connection_id = last_serialized_server_connection_id_; | 
 |       } else { | 
 |         header->source_connection_id = last_serialized_client_connection_id_; | 
 |       } | 
 |     } | 
 |  | 
 |     if (!ValidateReceivedConnectionIds(*header)) { | 
 |       return false; | 
 |     } | 
 |  | 
 |     if (header->version_flag && | 
 |         header->long_packet_type != VERSION_NEGOTIATION && | 
 |         !(header->type_byte & FLAGS_FIXED_BIT)) { | 
 |       set_detailed_error("Fixed bit is 0 in long header."); | 
 |       return false; | 
 |     } | 
 |     if (!header->version_flag && !(header->type_byte & FLAGS_FIXED_BIT)) { | 
 |       set_detailed_error("Fixed bit is 0 in short header."); | 
 |       return false; | 
 |     } | 
 |     if (!header->version_flag) { | 
 |       if (!version_.HasHeaderProtection()) { | 
 |         header->packet_number_length = | 
 |             GetShortHeaderPacketNumberLength(header->type_byte); | 
 |       } | 
 |       return true; | 
 |     } | 
 |     if (header->long_packet_type == RETRY) { | 
 |       if (!version().SupportsRetry()) { | 
 |         set_detailed_error("RETRY not supported in this version."); | 
 |         return false; | 
 |       } | 
 |       if (perspective_ == Perspective::IS_SERVER) { | 
 |         set_detailed_error("Client-initiated RETRY is invalid."); | 
 |         return false; | 
 |       } | 
 |       return true; | 
 |     } | 
 |     if (header->version.IsKnown() && !header->version.HasHeaderProtection()) { | 
 |       header->packet_number_length = | 
 |           GetLongHeaderPacketNumberLength(header->type_byte); | 
 |     } | 
 |  | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (!ProcessIetfHeaderTypeByte(reader, header)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint8_t destination_connection_id_length = | 
 |       header->destination_connection_id_included == CONNECTION_ID_PRESENT | 
 |           ? (perspective_ == Perspective::IS_SERVER | 
 |                  ? expected_server_connection_id_length_ | 
 |                  : expected_client_connection_id_length_) | 
 |           : 0; | 
 |   uint8_t source_connection_id_length = | 
 |       header->source_connection_id_included == CONNECTION_ID_PRESENT | 
 |           ? (perspective_ == Perspective::IS_CLIENT | 
 |                  ? expected_server_connection_id_length_ | 
 |                  : expected_client_connection_id_length_) | 
 |           : 0; | 
 |   if (header->form == IETF_QUIC_LONG_HEADER_PACKET) { | 
 |     if (!ProcessAndValidateIetfConnectionIdLength( | 
 |             reader, header->version, perspective_, | 
 |             /*should_update_expected_server_connection_id_length=*/false, | 
 |             &expected_server_connection_id_length_, | 
 |             &destination_connection_id_length, &source_connection_id_length, | 
 |             &detailed_error_)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   // Read connection ID. | 
 |   if (!reader->ReadConnectionId(&header->destination_connection_id, | 
 |                                 destination_connection_id_length)) { | 
 |     set_detailed_error("Unable to read destination connection ID."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadConnectionId(&header->source_connection_id, | 
 |                                 source_connection_id_length)) { | 
 |     set_detailed_error("Unable to read source connection ID."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (header->source_connection_id_included == CONNECTION_ID_ABSENT) { | 
 |     if (!header->source_connection_id.IsEmpty()) { | 
 |       DCHECK(!version_.SupportsClientConnectionIds()); | 
 |       set_detailed_error("Client connection ID not supported in this version."); | 
 |       return false; | 
 |     } | 
 |     if (perspective_ == Perspective::IS_CLIENT) { | 
 |       header->source_connection_id = last_serialized_server_connection_id_; | 
 |     } else { | 
 |       header->source_connection_id = last_serialized_client_connection_id_; | 
 |     } | 
 |   } | 
 |  | 
 |   return ValidateReceivedConnectionIds(*header); | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessAndCalculatePacketNumber( | 
 |     QuicDataReader* reader, | 
 |     QuicPacketNumberLength packet_number_length, | 
 |     QuicPacketNumber base_packet_number, | 
 |     uint64_t* packet_number) { | 
 |   uint64_t wire_packet_number; | 
 |   if (!reader->ReadBytesToUInt64(packet_number_length, &wire_packet_number)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // TODO(ianswett): Explore the usefulness of trying multiple packet numbers | 
 |   // in case the first guess is incorrect. | 
 |   *packet_number = CalculatePacketNumberFromWire( | 
 |       packet_number_length, base_packet_number, wire_packet_number); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessFrameData(QuicDataReader* reader, | 
 |                                   const QuicPacketHeader& header) { | 
 |   DCHECK(!VersionHasIetfQuicFrames(version_.transport_version)) | 
 |       << "IETF QUIC Framing negotiated but attempting to process frames as " | 
 |          "non-IETF QUIC."; | 
 |   if (reader->IsDoneReading()) { | 
 |     set_detailed_error("Packet has no frames."); | 
 |     return RaiseError(QUIC_MISSING_PAYLOAD); | 
 |   } | 
 |   QUIC_DVLOG(2) << ENDPOINT << "Processing packet with header " << header; | 
 |   while (!reader->IsDoneReading()) { | 
 |     uint8_t frame_type; | 
 |     if (!reader->ReadBytes(&frame_type, 1)) { | 
 |       set_detailed_error("Unable to read frame type."); | 
 |       return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |     } | 
 |     const uint8_t special_mask = transport_version() <= QUIC_VERSION_43 | 
 |                                      ? kQuicFrameTypeBrokenMask | 
 |                                      : kQuicFrameTypeSpecialMask; | 
 |     if (frame_type & special_mask) { | 
 |       // Stream Frame | 
 |       if (frame_type & kQuicFrameTypeStreamMask) { | 
 |         QuicStreamFrame frame; | 
 |         if (!ProcessStreamFrame(reader, frame_type, &frame)) { | 
 |           return RaiseError(QUIC_INVALID_STREAM_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing stream frame " << frame; | 
 |         if (!visitor_->OnStreamFrame(frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       // Ack Frame | 
 |       if (frame_type & kQuicFrameTypeAckMask) { | 
 |         if (!ProcessAckFrame(reader, frame_type)) { | 
 |           return RaiseError(QUIC_INVALID_ACK_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing ACK frame"; | 
 |         continue; | 
 |       } | 
 |  | 
 |       // This was a special frame type that did not match any | 
 |       // of the known ones. Error. | 
 |       set_detailed_error("Illegal frame type."); | 
 |       QUIC_DLOG(WARNING) << ENDPOINT << "Illegal frame type: " | 
 |                          << static_cast<int>(frame_type); | 
 |       return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |     } | 
 |  | 
 |     switch (frame_type) { | 
 |       case PADDING_FRAME: { | 
 |         QuicPaddingFrame frame; | 
 |         ProcessPaddingFrame(reader, &frame); | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing padding frame " << frame; | 
 |         if (!visitor_->OnPaddingFrame(frame)) { | 
 |           QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case RST_STREAM_FRAME: { | 
 |         QuicRstStreamFrame frame; | 
 |         if (!ProcessRstStreamFrame(reader, &frame)) { | 
 |           return RaiseError(QUIC_INVALID_RST_STREAM_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing reset stream frame " << frame; | 
 |         if (!visitor_->OnRstStreamFrame(frame)) { | 
 |           QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case CONNECTION_CLOSE_FRAME: { | 
 |         QuicConnectionCloseFrame frame; | 
 |         if (!ProcessConnectionCloseFrame(reader, &frame)) { | 
 |           return RaiseError(QUIC_INVALID_CONNECTION_CLOSE_DATA); | 
 |         } | 
 |  | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing connection close frame " | 
 |                       << frame; | 
 |         if (!visitor_->OnConnectionCloseFrame(frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case GOAWAY_FRAME: { | 
 |         QuicGoAwayFrame goaway_frame; | 
 |         if (!ProcessGoAwayFrame(reader, &goaway_frame)) { | 
 |           return RaiseError(QUIC_INVALID_GOAWAY_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing go away frame " | 
 |                       << goaway_frame; | 
 |         if (!visitor_->OnGoAwayFrame(goaway_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case WINDOW_UPDATE_FRAME: { | 
 |         QuicWindowUpdateFrame window_update_frame; | 
 |         if (!ProcessWindowUpdateFrame(reader, &window_update_frame)) { | 
 |           return RaiseError(QUIC_INVALID_WINDOW_UPDATE_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing window update frame " | 
 |                       << window_update_frame; | 
 |         if (!visitor_->OnWindowUpdateFrame(window_update_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case BLOCKED_FRAME: { | 
 |         QuicBlockedFrame blocked_frame; | 
 |         if (!ProcessBlockedFrame(reader, &blocked_frame)) { | 
 |           return RaiseError(QUIC_INVALID_BLOCKED_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing blocked frame " | 
 |                       << blocked_frame; | 
 |         if (!visitor_->OnBlockedFrame(blocked_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |  | 
 |       case STOP_WAITING_FRAME: { | 
 |         if (GetQuicReloadableFlag(quic_do_not_accept_stop_waiting) && | 
 |             version_.transport_version > QUIC_VERSION_43) { | 
 |           QUIC_RELOADABLE_FLAG_COUNT(quic_do_not_accept_stop_waiting); | 
 |           set_detailed_error("STOP WAITING not supported in version 44+."); | 
 |           return RaiseError(QUIC_INVALID_STOP_WAITING_DATA); | 
 |         } | 
 |         QuicStopWaitingFrame stop_waiting_frame; | 
 |         if (!ProcessStopWaitingFrame(reader, header, &stop_waiting_frame)) { | 
 |           return RaiseError(QUIC_INVALID_STOP_WAITING_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing stop waiting frame " | 
 |                       << stop_waiting_frame; | 
 |         if (!visitor_->OnStopWaitingFrame(stop_waiting_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         continue; | 
 |       } | 
 |       case PING_FRAME: { | 
 |         // Ping has no payload. | 
 |         QuicPingFrame ping_frame; | 
 |         if (!visitor_->OnPingFrame(ping_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing ping frame " << ping_frame; | 
 |         continue; | 
 |       } | 
 |       case IETF_EXTENSION_MESSAGE_NO_LENGTH: | 
 |         QUIC_FALLTHROUGH_INTENDED; | 
 |       case IETF_EXTENSION_MESSAGE: { | 
 |         QuicMessageFrame message_frame; | 
 |         if (!ProcessMessageFrame(reader, | 
 |                                  frame_type == IETF_EXTENSION_MESSAGE_NO_LENGTH, | 
 |                                  &message_frame)) { | 
 |           return RaiseError(QUIC_INVALID_MESSAGE_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing message frame " | 
 |                       << message_frame; | 
 |         if (!visitor_->OnMessageFrame(message_frame)) { | 
 |           QUIC_DVLOG(1) << ENDPOINT | 
 |                         << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         break; | 
 |       } | 
 |       case CRYPTO_FRAME: { | 
 |         if (!QuicVersionUsesCryptoFrames(version_.transport_version)) { | 
 |           set_detailed_error("Illegal frame type."); | 
 |           return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |         } | 
 |         QuicCryptoFrame frame; | 
 |         if (!ProcessCryptoFrame(reader, GetEncryptionLevel(header), &frame)) { | 
 |           return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |         } | 
 |         QUIC_DVLOG(2) << ENDPOINT << "Processing crypto frame " << frame; | 
 |         if (!visitor_->OnCryptoFrame(frame)) { | 
 |           QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |           // Returning true since there was no parsing error. | 
 |           return true; | 
 |         } | 
 |         break; | 
 |       } | 
 |  | 
 |       default: | 
 |         set_detailed_error("Illegal frame type."); | 
 |         QUIC_DLOG(WARNING) << ENDPOINT << "Illegal frame type: " | 
 |                            << static_cast<int>(frame_type); | 
 |         return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |     } | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfFrameData(QuicDataReader* reader, | 
 |                                       const QuicPacketHeader& header) { | 
 |   DCHECK(VersionHasIetfQuicFrames(version_.transport_version)) | 
 |       << "Attempt to process frames as IETF frames but version (" | 
 |       << version_.transport_version << ") does not support IETF Framing."; | 
 |  | 
 |   if (reader->IsDoneReading()) { | 
 |     set_detailed_error("Packet has no frames."); | 
 |     return RaiseError(QUIC_MISSING_PAYLOAD); | 
 |   } | 
 |  | 
 |   QUIC_DVLOG(2) << ENDPOINT << "Processing IETF packet with header " << header; | 
 |   while (!reader->IsDoneReading()) { | 
 |     uint64_t frame_type; | 
 |     // Will be the number of bytes into which frame_type was encoded. | 
 |     size_t encoded_bytes = reader->BytesRemaining(); | 
 |     if (!reader->ReadVarInt62(&frame_type)) { | 
 |       set_detailed_error("Unable to read frame type."); | 
 |       return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |     } | 
 |     current_received_frame_type_ = frame_type; | 
 |  | 
 |     // Is now the number of bytes into which the frame type was encoded. | 
 |     encoded_bytes -= reader->BytesRemaining(); | 
 |  | 
 |     // Check that the frame type is minimally encoded. | 
 |     if (encoded_bytes != | 
 |         static_cast<size_t>(QuicDataWriter::GetVarInt62Len(frame_type))) { | 
 |       // The frame type was not minimally encoded. | 
 |       set_detailed_error("Frame type not minimally encoded."); | 
 |       return RaiseError(IETF_QUIC_PROTOCOL_VIOLATION); | 
 |     } | 
 |  | 
 |     if (IS_IETF_STREAM_FRAME(frame_type)) { | 
 |       QuicStreamFrame frame; | 
 |       if (!ProcessIetfStreamFrame(reader, frame_type, &frame)) { | 
 |         return RaiseError(QUIC_INVALID_STREAM_DATA); | 
 |       } | 
 |       QUIC_DVLOG(2) << ENDPOINT << "Processing IETF stream frame " << frame; | 
 |       if (!visitor_->OnStreamFrame(frame)) { | 
 |         QUIC_DVLOG(1) << ENDPOINT | 
 |                       << "Visitor asked to stop further processing."; | 
 |         // Returning true since there was no parsing error. | 
 |         return true; | 
 |       } | 
 |     } else { | 
 |       switch (frame_type) { | 
 |         case IETF_PADDING: { | 
 |           QuicPaddingFrame frame; | 
 |           ProcessPaddingFrame(reader, &frame); | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF padding frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnPaddingFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_RST_STREAM: { | 
 |           QuicRstStreamFrame frame; | 
 |           if (!ProcessIetfResetStreamFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_RST_STREAM_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF reset stream frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnRstStreamFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_APPLICATION_CLOSE: | 
 |         case IETF_CONNECTION_CLOSE: { | 
 |           QuicConnectionCloseFrame frame; | 
 |           if (!ProcessIetfConnectionCloseFrame( | 
 |                   reader, | 
 |                   (frame_type == IETF_CONNECTION_CLOSE) | 
 |                       ? IETF_QUIC_TRANSPORT_CONNECTION_CLOSE | 
 |                       : IETF_QUIC_APPLICATION_CONNECTION_CLOSE, | 
 |                   &frame)) { | 
 |             return RaiseError(QUIC_INVALID_CONNECTION_CLOSE_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF connection close frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnConnectionCloseFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_MAX_DATA: { | 
 |           QuicWindowUpdateFrame frame; | 
 |           if (!ProcessMaxDataFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_MAX_DATA_FRAME_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF max data frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnWindowUpdateFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_MAX_STREAM_DATA: { | 
 |           QuicWindowUpdateFrame frame; | 
 |           if (!ProcessMaxStreamDataFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_MAX_STREAM_DATA_FRAME_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF max stream data frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnWindowUpdateFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_MAX_STREAMS_BIDIRECTIONAL: | 
 |         case IETF_MAX_STREAMS_UNIDIRECTIONAL: { | 
 |           QuicMaxStreamsFrame frame; | 
 |           if (!ProcessMaxStreamsFrame(reader, &frame, frame_type)) { | 
 |             return RaiseError(QUIC_MAX_STREAMS_DATA); | 
 |           } | 
 |           QUIC_CODE_COUNT_N(quic_max_streams_received, 1, 2); | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF max streams frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnMaxStreamsFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_PING: { | 
 |           // Ping has no payload. | 
 |           QuicPingFrame ping_frame; | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF ping frame " | 
 |                         << ping_frame; | 
 |           if (!visitor_->OnPingFrame(ping_frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_DATA_BLOCKED: { | 
 |           QuicBlockedFrame frame; | 
 |           if (!ProcessDataBlockedFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_BLOCKED_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF blocked frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnBlockedFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_STREAM_DATA_BLOCKED: { | 
 |           QuicBlockedFrame frame; | 
 |           if (!ProcessStreamDataBlockedFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_STREAM_BLOCKED_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF stream blocked frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnBlockedFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_STREAMS_BLOCKED_UNIDIRECTIONAL: | 
 |         case IETF_STREAMS_BLOCKED_BIDIRECTIONAL: { | 
 |           QuicStreamsBlockedFrame frame; | 
 |           if (!ProcessStreamsBlockedFrame(reader, &frame, frame_type)) { | 
 |             return RaiseError(QUIC_STREAMS_BLOCKED_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF streams blocked frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnStreamsBlockedFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_NEW_CONNECTION_ID: { | 
 |           QuicNewConnectionIdFrame frame; | 
 |           if (!ProcessNewConnectionIdFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_NEW_CONNECTION_ID_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT | 
 |                         << "Processing IETF new connection ID frame " << frame; | 
 |           if (!visitor_->OnNewConnectionIdFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_RETIRE_CONNECTION_ID: { | 
 |           QuicRetireConnectionIdFrame frame; | 
 |           if (!ProcessRetireConnectionIdFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_RETIRE_CONNECTION_ID_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT | 
 |                         << "Processing IETF retire connection ID frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnRetireConnectionIdFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_NEW_TOKEN: { | 
 |           QuicNewTokenFrame frame; | 
 |           if (!ProcessNewTokenFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_NEW_TOKEN); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF new token frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnNewTokenFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_STOP_SENDING: { | 
 |           QuicStopSendingFrame frame; | 
 |           if (!ProcessStopSendingFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_STOP_SENDING_FRAME_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF stop sending frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnStopSendingFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_ACK_ECN: | 
 |         case IETF_ACK: { | 
 |           QuicAckFrame frame; | 
 |           if (!ProcessIetfAckFrame(reader, frame_type, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_ACK_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF ACK frame " << frame; | 
 |           break; | 
 |         } | 
 |         case IETF_PATH_CHALLENGE: { | 
 |           QuicPathChallengeFrame frame; | 
 |           if (!ProcessPathChallengeFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_PATH_CHALLENGE_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF path challenge frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnPathChallengeFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_PATH_RESPONSE: { | 
 |           QuicPathResponseFrame frame; | 
 |           if (!ProcessPathResponseFrame(reader, &frame)) { | 
 |             return RaiseError(QUIC_INVALID_PATH_RESPONSE_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF path response frame " | 
 |                         << frame; | 
 |           if (!visitor_->OnPathResponseFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_EXTENSION_MESSAGE_NO_LENGTH_V99: | 
 |           QUIC_FALLTHROUGH_INTENDED; | 
 |         case IETF_EXTENSION_MESSAGE_V99: { | 
 |           QuicMessageFrame message_frame; | 
 |           if (!ProcessMessageFrame( | 
 |                   reader, frame_type == IETF_EXTENSION_MESSAGE_NO_LENGTH_V99, | 
 |                   &message_frame)) { | 
 |             return RaiseError(QUIC_INVALID_MESSAGE_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF message frame " | 
 |                         << message_frame; | 
 |           if (!visitor_->OnMessageFrame(message_frame)) { | 
 |             QUIC_DVLOG(1) << ENDPOINT | 
 |                           << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_CRYPTO: { | 
 |           QuicCryptoFrame frame; | 
 |           if (!ProcessCryptoFrame(reader, GetEncryptionLevel(header), &frame)) { | 
 |             return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing IETF crypto frame " << frame; | 
 |           if (!visitor_->OnCryptoFrame(frame)) { | 
 |             QUIC_DVLOG(1) << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           break; | 
 |         } | 
 |         case IETF_HANDSHAKE_DONE: { | 
 |           // HANDSHAKE_DONE has no payload. | 
 |           QuicHandshakeDoneFrame handshake_done_frame; | 
 |           if (!visitor_->OnHandshakeDoneFrame(handshake_done_frame)) { | 
 |             QUIC_DVLOG(1) << ENDPOINT | 
 |                           << "Visitor asked to stop further processing."; | 
 |             // Returning true since there was no parsing error. | 
 |             return true; | 
 |           } | 
 |           QUIC_DVLOG(2) << ENDPOINT << "Processing handshake done frame " | 
 |                         << handshake_done_frame; | 
 |           break; | 
 |         } | 
 |  | 
 |         default: | 
 |           set_detailed_error("Illegal frame type."); | 
 |           QUIC_DLOG(WARNING) | 
 |               << ENDPOINT | 
 |               << "Illegal frame type: " << static_cast<int>(frame_type); | 
 |           return RaiseError(QUIC_INVALID_FRAME_DATA); | 
 |       } | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | namespace { | 
 | // Create a mask that sets the last |num_bits| to 1 and the rest to 0. | 
 | inline uint8_t GetMaskFromNumBits(uint8_t num_bits) { | 
 |   return (1u << num_bits) - 1; | 
 | } | 
 |  | 
 | // Extract |num_bits| from |flags| offset by |offset|. | 
 | uint8_t ExtractBits(uint8_t flags, uint8_t num_bits, uint8_t offset) { | 
 |   return (flags >> offset) & GetMaskFromNumBits(num_bits); | 
 | } | 
 |  | 
 | // Extract the bit at position |offset| from |flags| as a bool. | 
 | bool ExtractBit(uint8_t flags, uint8_t offset) { | 
 |   return ((flags >> offset) & GetMaskFromNumBits(1)) != 0; | 
 | } | 
 |  | 
 | // Set |num_bits|, offset by |offset| to |val| in |flags|. | 
 | void SetBits(uint8_t* flags, uint8_t val, uint8_t num_bits, uint8_t offset) { | 
 |   DCHECK_LE(val, GetMaskFromNumBits(num_bits)); | 
 |   *flags |= val << offset; | 
 | } | 
 |  | 
 | // Set the bit at position |offset| to |val| in |flags|. | 
 | void SetBit(uint8_t* flags, bool val, uint8_t offset) { | 
 |   SetBits(flags, val ? 1 : 0, 1, offset); | 
 | } | 
 | }  // namespace | 
 |  | 
 | bool QuicFramer::ProcessStreamFrame(QuicDataReader* reader, | 
 |                                     uint8_t frame_type, | 
 |                                     QuicStreamFrame* frame) { | 
 |   uint8_t stream_flags = frame_type; | 
 |  | 
 |   uint8_t stream_id_length = 0; | 
 |   uint8_t offset_length = 4; | 
 |   bool has_data_length = true; | 
 |   stream_flags &= ~kQuicFrameTypeStreamMask; | 
 |  | 
 |   // Read from right to left: StreamID, Offset, Data Length, Fin. | 
 |   stream_id_length = (stream_flags & kQuicStreamIDLengthMask) + 1; | 
 |   stream_flags >>= kQuicStreamIdShift; | 
 |  | 
 |   offset_length = (stream_flags & kQuicStreamOffsetMask); | 
 |   // There is no encoding for 1 byte, only 0 and 2 through 8. | 
 |   if (offset_length > 0) { | 
 |     offset_length += 1; | 
 |   } | 
 |   stream_flags >>= kQuicStreamShift; | 
 |  | 
 |   has_data_length = | 
 |       (stream_flags & kQuicStreamDataLengthMask) == kQuicStreamDataLengthMask; | 
 |   stream_flags >>= kQuicStreamDataLengthShift; | 
 |  | 
 |   frame->fin = (stream_flags & kQuicStreamFinMask) == kQuicStreamFinShift; | 
 |  | 
 |   uint64_t stream_id; | 
 |   if (!reader->ReadBytesToUInt64(stream_id_length, &stream_id)) { | 
 |     set_detailed_error("Unable to read stream_id."); | 
 |     return false; | 
 |   } | 
 |   frame->stream_id = static_cast<QuicStreamId>(stream_id); | 
 |  | 
 |   if (!reader->ReadBytesToUInt64(offset_length, &frame->offset)) { | 
 |     set_detailed_error("Unable to read offset."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // TODO(ianswett): Don't use quiche::QuicheStringPiece as an intermediary. | 
 |   quiche::QuicheStringPiece data; | 
 |   if (has_data_length) { | 
 |     if (!reader->ReadStringPiece16(&data)) { | 
 |       set_detailed_error("Unable to read frame data."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     if (!reader->ReadStringPiece(&data, reader->BytesRemaining())) { | 
 |       set_detailed_error("Unable to read frame data."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |   frame->data_buffer = data.data(); | 
 |   frame->data_length = static_cast<uint16_t>(data.length()); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfStreamFrame(QuicDataReader* reader, | 
 |                                         uint8_t frame_type, | 
 |                                         QuicStreamFrame* frame) { | 
 |   // Read stream id from the frame. It's always present. | 
 |   if (!ReadUint32FromVarint62(reader, IETF_STREAM, &frame->stream_id)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // If we have a data offset, read it. If not, set to 0. | 
 |   if (frame_type & IETF_STREAM_FRAME_OFF_BIT) { | 
 |     if (!reader->ReadVarInt62(&frame->offset)) { | 
 |       set_detailed_error("Unable to read stream data offset."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     // no offset in the frame, ensure it's 0 in the Frame. | 
 |     frame->offset = 0; | 
 |   } | 
 |  | 
 |   // If we have a data length, read it. If not, set to 0. | 
 |   if (frame_type & IETF_STREAM_FRAME_LEN_BIT) { | 
 |     uint64_t length; | 
 |     if (!reader->ReadVarInt62(&length)) { | 
 |       set_detailed_error("Unable to read stream data length."); | 
 |       return false; | 
 |     } | 
 |     if (length > std::numeric_limits<decltype(frame->data_length)>::max()) { | 
 |       set_detailed_error("Stream data length is too large."); | 
 |       return false; | 
 |     } | 
 |     frame->data_length = length; | 
 |   } else { | 
 |     // no length in the frame, it is the number of bytes remaining in the | 
 |     // packet. | 
 |     frame->data_length = reader->BytesRemaining(); | 
 |   } | 
 |  | 
 |   if (frame_type & IETF_STREAM_FRAME_FIN_BIT) { | 
 |     frame->fin = true; | 
 |   } else { | 
 |     frame->fin = false; | 
 |   } | 
 |  | 
 |   // TODO(ianswett): Don't use quiche::QuicheStringPiece as an intermediary. | 
 |   quiche::QuicheStringPiece data; | 
 |   if (!reader->ReadStringPiece(&data, frame->data_length)) { | 
 |     set_detailed_error("Unable to read frame data."); | 
 |     return false; | 
 |   } | 
 |   frame->data_buffer = data.data(); | 
 |   DCHECK_EQ(frame->data_length, data.length()); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessCryptoFrame(QuicDataReader* reader, | 
 |                                     EncryptionLevel encryption_level, | 
 |                                     QuicCryptoFrame* frame) { | 
 |   frame->level = encryption_level; | 
 |   if (!reader->ReadVarInt62(&frame->offset)) { | 
 |     set_detailed_error("Unable to read crypto data offset."); | 
 |     return false; | 
 |   } | 
 |   uint64_t len; | 
 |   if (!reader->ReadVarInt62(&len) || | 
 |       len > std::numeric_limits<QuicPacketLength>::max()) { | 
 |     set_detailed_error("Invalid data length."); | 
 |     return false; | 
 |   } | 
 |   frame->data_length = len; | 
 |  | 
 |   // TODO(ianswett): Don't use quiche::QuicheStringPiece as an intermediary. | 
 |   quiche::QuicheStringPiece data; | 
 |   if (!reader->ReadStringPiece(&data, frame->data_length)) { | 
 |     set_detailed_error("Unable to read frame data."); | 
 |     return false; | 
 |   } | 
 |   frame->data_buffer = data.data(); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessAckFrame(QuicDataReader* reader, uint8_t frame_type) { | 
 |   const bool has_ack_blocks = | 
 |       ExtractBit(frame_type, kQuicHasMultipleAckBlocksOffset); | 
 |   uint8_t num_ack_blocks = 0; | 
 |   uint8_t num_received_packets = 0; | 
 |  | 
 |   // Determine the two lengths from the frame type: largest acked length, | 
 |   // ack block length. | 
 |   const QuicPacketNumberLength ack_block_length = ReadAckPacketNumberLength( | 
 |       ExtractBits(frame_type, kQuicSequenceNumberLengthNumBits, | 
 |                   kActBlockLengthOffset)); | 
 |   const QuicPacketNumberLength largest_acked_length = ReadAckPacketNumberLength( | 
 |       ExtractBits(frame_type, kQuicSequenceNumberLengthNumBits, | 
 |                   kLargestAckedOffset)); | 
 |  | 
 |   uint64_t largest_acked; | 
 |   if (!reader->ReadBytesToUInt64(largest_acked_length, &largest_acked)) { | 
 |     set_detailed_error("Unable to read largest acked."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (largest_acked < first_sending_packet_number_.ToUint64()) { | 
 |     // Connection always sends packet starting from kFirstSendingPacketNumber > | 
 |     // 0, peer has observed an unsent packet. | 
 |     set_detailed_error("Largest acked is 0."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint64_t ack_delay_time_us; | 
 |   if (!reader->ReadUFloat16(&ack_delay_time_us)) { | 
 |     set_detailed_error("Unable to read ack delay time."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!visitor_->OnAckFrameStart( | 
 |           QuicPacketNumber(largest_acked), | 
 |           ack_delay_time_us == kUFloat16MaxValue | 
 |               ? QuicTime::Delta::Infinite() | 
 |               : QuicTime::Delta::FromMicroseconds(ack_delay_time_us))) { | 
 |     // The visitor suppresses further processing of the packet. Although this is | 
 |     // not a parsing error, returns false as this is in middle of processing an | 
 |     // ack frame, | 
 |     set_detailed_error("Visitor suppresses further processing of ack frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (has_ack_blocks && !reader->ReadUInt8(&num_ack_blocks)) { | 
 |     set_detailed_error("Unable to read num of ack blocks."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint64_t first_block_length; | 
 |   if (!reader->ReadBytesToUInt64(ack_block_length, &first_block_length)) { | 
 |     set_detailed_error("Unable to read first ack block length."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (first_block_length == 0) { | 
 |     set_detailed_error("First block length is zero."); | 
 |     return false; | 
 |   } | 
 |   bool first_ack_block_underflow = first_block_length > largest_acked + 1; | 
 |   if (first_block_length + first_sending_packet_number_.ToUint64() > | 
 |       largest_acked + 1) { | 
 |     first_ack_block_underflow = true; | 
 |   } | 
 |   if (first_ack_block_underflow) { | 
 |     set_detailed_error( | 
 |         quiche::QuicheStrCat("Underflow with first ack block length ", | 
 |                              first_block_length, " largest acked is ", | 
 |                              largest_acked, ".") | 
 |             .c_str()); | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint64_t first_received = largest_acked + 1 - first_block_length; | 
 |   if (!visitor_->OnAckRange(QuicPacketNumber(first_received), | 
 |                             QuicPacketNumber(largest_acked + 1))) { | 
 |     // The visitor suppresses further processing of the packet. Although | 
 |     // this is not a parsing error, returns false as this is in middle | 
 |     // of processing an ack frame, | 
 |     set_detailed_error("Visitor suppresses further processing of ack frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (num_ack_blocks > 0) { | 
 |     for (size_t i = 0; i < num_ack_blocks; ++i) { | 
 |       uint8_t gap = 0; | 
 |       if (!reader->ReadUInt8(&gap)) { | 
 |         set_detailed_error("Unable to read gap to next ack block."); | 
 |         return false; | 
 |       } | 
 |       uint64_t current_block_length; | 
 |       if (!reader->ReadBytesToUInt64(ack_block_length, ¤t_block_length)) { | 
 |         set_detailed_error("Unable to ack block length."); | 
 |         return false; | 
 |       } | 
 |       bool ack_block_underflow = first_received < gap + current_block_length; | 
 |       if (first_received < gap + current_block_length + | 
 |                                first_sending_packet_number_.ToUint64()) { | 
 |         ack_block_underflow = true; | 
 |       } | 
 |       if (ack_block_underflow) { | 
 |         set_detailed_error( | 
 |             quiche::QuicheStrCat("Underflow with ack block length ", | 
 |                                  current_block_length, ", end of block is ", | 
 |                                  first_received - gap, ".") | 
 |                 .c_str()); | 
 |         return false; | 
 |       } | 
 |  | 
 |       first_received -= (gap + current_block_length); | 
 |       if (current_block_length > 0) { | 
 |         if (!visitor_->OnAckRange( | 
 |                 QuicPacketNumber(first_received), | 
 |                 QuicPacketNumber(first_received) + current_block_length)) { | 
 |           // The visitor suppresses further processing of the packet. Although | 
 |           // this is not a parsing error, returns false as this is in middle | 
 |           // of processing an ack frame, | 
 |           set_detailed_error( | 
 |               "Visitor suppresses further processing of ack frame."); | 
 |           return false; | 
 |         } | 
 |       } | 
 |     } | 
 |   } | 
 |  | 
 |   if (!reader->ReadUInt8(&num_received_packets)) { | 
 |     set_detailed_error("Unable to read num received packets."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!ProcessTimestampsInAckFrame(num_received_packets, | 
 |                                    QuicPacketNumber(largest_acked), reader)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Done processing the ACK frame. | 
 |   if (!visitor_->OnAckFrameEnd(QuicPacketNumber(first_received))) { | 
 |     set_detailed_error( | 
 |         "Error occurs when visitor finishes processing the ACK frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessTimestampsInAckFrame(uint8_t num_received_packets, | 
 |                                              QuicPacketNumber largest_acked, | 
 |                                              QuicDataReader* reader) { | 
 |   if (num_received_packets == 0) { | 
 |     return true; | 
 |   } | 
 |   uint8_t delta_from_largest_observed; | 
 |   if (!reader->ReadUInt8(&delta_from_largest_observed)) { | 
 |     set_detailed_error("Unable to read sequence delta in received packets."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (largest_acked.ToUint64() <= delta_from_largest_observed) { | 
 |     set_detailed_error( | 
 |         quiche::QuicheStrCat("delta_from_largest_observed too high: ", | 
 |                              delta_from_largest_observed, | 
 |                              ", largest_acked: ", largest_acked.ToUint64()) | 
 |             .c_str()); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Time delta from the framer creation. | 
 |   uint32_t time_delta_us; | 
 |   if (!reader->ReadUInt32(&time_delta_us)) { | 
 |     set_detailed_error("Unable to read time delta in received packets."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicPacketNumber seq_num = largest_acked - delta_from_largest_observed; | 
 |   if (process_timestamps_) { | 
 |     last_timestamp_ = CalculateTimestampFromWire(time_delta_us); | 
 |  | 
 |     visitor_->OnAckTimestamp(seq_num, creation_time_ + last_timestamp_); | 
 |   } | 
 |  | 
 |   for (uint8_t i = 1; i < num_received_packets; ++i) { | 
 |     if (!reader->ReadUInt8(&delta_from_largest_observed)) { | 
 |       set_detailed_error("Unable to read sequence delta in received packets."); | 
 |       return false; | 
 |     } | 
 |     if (largest_acked.ToUint64() <= delta_from_largest_observed) { | 
 |       set_detailed_error( | 
 |           quiche::QuicheStrCat("delta_from_largest_observed too high: ", | 
 |                                delta_from_largest_observed, | 
 |                                ", largest_acked: ", largest_acked.ToUint64()) | 
 |               .c_str()); | 
 |       return false; | 
 |     } | 
 |     seq_num = largest_acked - delta_from_largest_observed; | 
 |  | 
 |     // Time delta from the previous timestamp. | 
 |     uint64_t incremental_time_delta_us; | 
 |     if (!reader->ReadUFloat16(&incremental_time_delta_us)) { | 
 |       set_detailed_error( | 
 |           "Unable to read incremental time delta in received packets."); | 
 |       return false; | 
 |     } | 
 |  | 
 |     if (process_timestamps_) { | 
 |       last_timestamp_ = last_timestamp_ + QuicTime::Delta::FromMicroseconds( | 
 |                                               incremental_time_delta_us); | 
 |       visitor_->OnAckTimestamp(seq_num, creation_time_ + last_timestamp_); | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfAckFrame(QuicDataReader* reader, | 
 |                                      uint64_t frame_type, | 
 |                                      QuicAckFrame* ack_frame) { | 
 |   uint64_t largest_acked; | 
 |   if (!reader->ReadVarInt62(&largest_acked)) { | 
 |     set_detailed_error("Unable to read largest acked."); | 
 |     return false; | 
 |   } | 
 |   if (largest_acked < first_sending_packet_number_.ToUint64()) { | 
 |     // Connection always sends packet starting from kFirstSendingPacketNumber > | 
 |     // 0, peer has observed an unsent packet. | 
 |     set_detailed_error("Largest acked is 0."); | 
 |     return false; | 
 |   } | 
 |   ack_frame->largest_acked = static_cast<QuicPacketNumber>(largest_acked); | 
 |   uint64_t ack_delay_time_in_us; | 
 |   if (!reader->ReadVarInt62(&ack_delay_time_in_us)) { | 
 |     set_detailed_error("Unable to read ack delay time."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (ack_delay_time_in_us >= (kVarInt62MaxValue >> peer_ack_delay_exponent_)) { | 
 |     ack_frame->ack_delay_time = QuicTime::Delta::Infinite(); | 
 |   } else { | 
 |     ack_delay_time_in_us = (ack_delay_time_in_us << peer_ack_delay_exponent_); | 
 |     ack_frame->ack_delay_time = | 
 |         QuicTime::Delta::FromMicroseconds(ack_delay_time_in_us); | 
 |   } | 
 |   if (!visitor_->OnAckFrameStart(QuicPacketNumber(largest_acked), | 
 |                                  ack_frame->ack_delay_time)) { | 
 |     // The visitor suppresses further processing of the packet. Although this is | 
 |     // not a parsing error, returns false as this is in middle of processing an | 
 |     // ACK frame. | 
 |     set_detailed_error("Visitor suppresses further processing of ACK frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Get number of ACK blocks from the packet. | 
 |   uint64_t ack_block_count; | 
 |   if (!reader->ReadVarInt62(&ack_block_count)) { | 
 |     set_detailed_error("Unable to read ack block count."); | 
 |     return false; | 
 |   } | 
 |   // There always is a first ACK block, which is the (number of packets being | 
 |   // acked)-1, up to and including the packet at largest_acked. Therefore if the | 
 |   // value is 0, then only largest is acked. If it is 1, then largest-1, | 
 |   // largest] are acked, etc | 
 |   uint64_t ack_block_value; | 
 |   if (!reader->ReadVarInt62(&ack_block_value)) { | 
 |     set_detailed_error("Unable to read first ack block length."); | 
 |     return false; | 
 |   } | 
 |   // Calculate the packets being acked in the first block. | 
 |   //  +1 because AddRange implementation requires [low,high) | 
 |   uint64_t block_high = largest_acked + 1; | 
 |   uint64_t block_low = largest_acked - ack_block_value; | 
 |  | 
 |   // ack_block_value is the number of packets preceding the | 
 |   // largest_acked packet which are in the block being acked. Thus, | 
 |   // its maximum value is largest_acked-1. Test this, reporting an | 
 |   // error if the value is wrong. | 
 |   if (ack_block_value + first_sending_packet_number_.ToUint64() > | 
 |       largest_acked) { | 
 |     set_detailed_error( | 
 |         quiche::QuicheStrCat("Underflow with first ack block length ", | 
 |                              ack_block_value + 1, " largest acked is ", | 
 |                              largest_acked, ".") | 
 |             .c_str()); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!visitor_->OnAckRange(QuicPacketNumber(block_low), | 
 |                             QuicPacketNumber(block_high))) { | 
 |     // The visitor suppresses further processing of the packet. Although | 
 |     // this is not a parsing error, returns false as this is in middle | 
 |     // of processing an ACK frame. | 
 |     set_detailed_error("Visitor suppresses further processing of ACK frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   while (ack_block_count != 0) { | 
 |     uint64_t gap_block_value; | 
 |     // Get the sizes of the gap and ack blocks, | 
 |     if (!reader->ReadVarInt62(&gap_block_value)) { | 
 |       set_detailed_error("Unable to read gap block value."); | 
 |       return false; | 
 |     } | 
 |     // It's an error if the gap is larger than the space from packet | 
 |     // number 0 to the start of the block that's just been acked, PLUS | 
 |     // there must be space for at least 1 packet to be acked. For | 
 |     // example, if block_low is 10 and gap_block_value is 9, it means | 
 |     // the gap block is 10 packets long, leaving no room for a packet | 
 |     // to be acked. Thus, gap_block_value+2 can not be larger than | 
 |     // block_low. | 
 |     // The test is written this way to detect wrap-arounds. | 
 |     if ((gap_block_value + 2) > block_low) { | 
 |       set_detailed_error( | 
 |           quiche::QuicheStrCat("Underflow with gap block length ", | 
 |                                gap_block_value + 1, | 
 |                                " previous ack block start is ", block_low, ".") | 
 |               .c_str()); | 
 |       return false; | 
 |     } | 
 |  | 
 |     // Adjust block_high to be the top of the next ack block. | 
 |     // There is a gap of |gap_block_value| packets between the bottom | 
 |     // of ack block N and top of block N+1.  Note that gap_block_value | 
 |     // is he size of the gap minus 1 (per the QUIC protocol), and | 
 |     // block_high is the packet number of the first packet of the gap | 
 |     // (per the implementation of OnAckRange/AddAckRange, below). | 
 |     block_high = block_low - 1 - gap_block_value; | 
 |  | 
 |     if (!reader->ReadVarInt62(&ack_block_value)) { | 
 |       set_detailed_error("Unable to read ack block value."); | 
 |       return false; | 
 |     } | 
 |     if (ack_block_value + first_sending_packet_number_.ToUint64() > | 
 |         (block_high - 1)) { | 
 |       set_detailed_error( | 
 |           quiche::QuicheStrCat("Underflow with ack block length ", | 
 |                                ack_block_value + 1, " latest ack block end is ", | 
 |                                block_high - 1, ".") | 
 |               .c_str()); | 
 |       return false; | 
 |     } | 
 |     // Calculate the low end of the new nth ack block. The +1 is | 
 |     // because the encoded value is the blocksize-1. | 
 |     block_low = block_high - 1 - ack_block_value; | 
 |     if (!visitor_->OnAckRange(QuicPacketNumber(block_low), | 
 |                               QuicPacketNumber(block_high))) { | 
 |       // The visitor suppresses further processing of the packet. Although | 
 |       // this is not a parsing error, returns false as this is in middle | 
 |       // of processing an ACK frame. | 
 |       set_detailed_error("Visitor suppresses further processing of ACK frame."); | 
 |       return false; | 
 |     } | 
 |  | 
 |     // Another one done. | 
 |     ack_block_count--; | 
 |   } | 
 |  | 
 |   if (frame_type == IETF_ACK_ECN) { | 
 |     ack_frame->ecn_counters_populated = true; | 
 |     if (!reader->ReadVarInt62(&ack_frame->ect_0_count)) { | 
 |       set_detailed_error("Unable to read ack ect_0_count."); | 
 |       return false; | 
 |     } | 
 |     if (!reader->ReadVarInt62(&ack_frame->ect_1_count)) { | 
 |       set_detailed_error("Unable to read ack ect_1_count."); | 
 |       return false; | 
 |     } | 
 |     if (!reader->ReadVarInt62(&ack_frame->ecn_ce_count)) { | 
 |       set_detailed_error("Unable to read ack ecn_ce_count."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     ack_frame->ecn_counters_populated = false; | 
 |     ack_frame->ect_0_count = 0; | 
 |     ack_frame->ect_1_count = 0; | 
 |     ack_frame->ecn_ce_count = 0; | 
 |   } | 
 |   // TODO(fayang): Report ECN counts to visitor when they are actually used. | 
 |   if (!visitor_->OnAckFrameEnd(QuicPacketNumber(block_low))) { | 
 |     set_detailed_error( | 
 |         "Error occurs when visitor finishes processing the ACK frame."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessStopWaitingFrame(QuicDataReader* reader, | 
 |                                          const QuicPacketHeader& header, | 
 |                                          QuicStopWaitingFrame* stop_waiting) { | 
 |   uint64_t least_unacked_delta; | 
 |   if (!reader->ReadBytesToUInt64(header.packet_number_length, | 
 |                                  &least_unacked_delta)) { | 
 |     set_detailed_error("Unable to read least unacked delta."); | 
 |     return false; | 
 |   } | 
 |   if (header.packet_number.ToUint64() <= least_unacked_delta) { | 
 |     set_detailed_error("Invalid unacked delta."); | 
 |     return false; | 
 |   } | 
 |   stop_waiting->least_unacked = header.packet_number - least_unacked_delta; | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessRstStreamFrame(QuicDataReader* reader, | 
 |                                        QuicRstStreamFrame* frame) { | 
 |   if (!reader->ReadUInt32(&frame->stream_id)) { | 
 |     set_detailed_error("Unable to read stream_id."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadUInt64(&frame->byte_offset)) { | 
 |     set_detailed_error("Unable to read rst stream sent byte offset."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint32_t error_code; | 
 |   if (!reader->ReadUInt32(&error_code)) { | 
 |     set_detailed_error("Unable to read rst stream error code."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (error_code >= QUIC_STREAM_LAST_ERROR) { | 
 |     // Ignore invalid stream error code if any. | 
 |     error_code = QUIC_STREAM_LAST_ERROR; | 
 |   } | 
 |  | 
 |   frame->error_code = static_cast<QuicRstStreamErrorCode>(error_code); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessConnectionCloseFrame(QuicDataReader* reader, | 
 |                                              QuicConnectionCloseFrame* frame) { | 
 |   uint32_t error_code; | 
 |   frame->close_type = GOOGLE_QUIC_CONNECTION_CLOSE; | 
 |  | 
 |   if (!reader->ReadUInt32(&error_code)) { | 
 |     set_detailed_error("Unable to read connection close error code."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (error_code >= QUIC_LAST_ERROR) { | 
 |     // Ignore invalid QUIC error code if any. | 
 |     error_code = QUIC_LAST_ERROR; | 
 |   } | 
 |  | 
 |   // For Google QUIC connection closes, |wire_error_code| and |quic_error_code| | 
 |   // must have the same value. | 
 |   frame->wire_error_code = error_code; | 
 |   frame->quic_error_code = static_cast<QuicErrorCode>(error_code); | 
 |  | 
 |   quiche::QuicheStringPiece error_details; | 
 |   if (!reader->ReadStringPiece16(&error_details)) { | 
 |     set_detailed_error("Unable to read connection close error details."); | 
 |     return false; | 
 |   } | 
 |   frame->error_details = std::string(error_details); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessGoAwayFrame(QuicDataReader* reader, | 
 |                                     QuicGoAwayFrame* frame) { | 
 |   uint32_t error_code; | 
 |   if (!reader->ReadUInt32(&error_code)) { | 
 |     set_detailed_error("Unable to read go away error code."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (error_code >= QUIC_LAST_ERROR) { | 
 |     // Ignore invalid QUIC error code if any. | 
 |     error_code = QUIC_LAST_ERROR; | 
 |   } | 
 |   frame->error_code = static_cast<QuicErrorCode>(error_code); | 
 |  | 
 |   uint32_t stream_id; | 
 |   if (!reader->ReadUInt32(&stream_id)) { | 
 |     set_detailed_error("Unable to read last good stream id."); | 
 |     return false; | 
 |   } | 
 |   frame->last_good_stream_id = static_cast<QuicStreamId>(stream_id); | 
 |  | 
 |   quiche::QuicheStringPiece reason_phrase; | 
 |   if (!reader->ReadStringPiece16(&reason_phrase)) { | 
 |     set_detailed_error("Unable to read goaway reason."); | 
 |     return false; | 
 |   } | 
 |   frame->reason_phrase = std::string(reason_phrase); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessWindowUpdateFrame(QuicDataReader* reader, | 
 |                                           QuicWindowUpdateFrame* frame) { | 
 |   if (!reader->ReadUInt32(&frame->stream_id)) { | 
 |     set_detailed_error("Unable to read stream_id."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadUInt64(&frame->max_data)) { | 
 |     set_detailed_error("Unable to read window byte_offset."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessBlockedFrame(QuicDataReader* reader, | 
 |                                      QuicBlockedFrame* frame) { | 
 |   DCHECK(!VersionHasIetfQuicFrames(version_.transport_version)) | 
 |       << "Attempt to process non-IETF QUIC frames in an IETF QUIC version."; | 
 |  | 
 |   if (!reader->ReadUInt32(&frame->stream_id)) { | 
 |     set_detailed_error("Unable to read stream_id."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicFramer::ProcessPaddingFrame(QuicDataReader* reader, | 
 |                                      QuicPaddingFrame* frame) { | 
 |   // Type byte has been read. | 
 |   frame->num_padding_bytes = 1; | 
 |   uint8_t next_byte; | 
 |   while (!reader->IsDoneReading() && reader->PeekByte() == 0x00) { | 
 |     reader->ReadBytes(&next_byte, 1); | 
 |     DCHECK_EQ(0x00, next_byte); | 
 |     ++frame->num_padding_bytes; | 
 |   } | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessMessageFrame(QuicDataReader* reader, | 
 |                                      bool no_message_length, | 
 |                                      QuicMessageFrame* frame) { | 
 |   if (no_message_length) { | 
 |     quiche::QuicheStringPiece remaining(reader->ReadRemainingPayload()); | 
 |     frame->data = remaining.data(); | 
 |     frame->message_length = remaining.length(); | 
 |     return true; | 
 |   } | 
 |  | 
 |   uint64_t message_length; | 
 |   if (!reader->ReadVarInt62(&message_length)) { | 
 |     set_detailed_error("Unable to read message length"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece message_piece; | 
 |   if (!reader->ReadStringPiece(&message_piece, message_length)) { | 
 |     set_detailed_error("Unable to read message data"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   frame->data = message_piece.data(); | 
 |   frame->message_length = message_length; | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | // static | 
 | quiche::QuicheStringPiece QuicFramer::GetAssociatedDataFromEncryptedPacket( | 
 |     QuicTransportVersion version, | 
 |     const QuicEncryptedPacket& encrypted, | 
 |     QuicConnectionIdLength destination_connection_id_length, | 
 |     QuicConnectionIdLength source_connection_id_length, | 
 |     bool includes_version, | 
 |     bool includes_diversification_nonce, | 
 |     QuicPacketNumberLength packet_number_length, | 
 |     QuicVariableLengthIntegerLength retry_token_length_length, | 
 |     uint64_t retry_token_length, | 
 |     QuicVariableLengthIntegerLength length_length) { | 
 |   // TODO(ianswett): This is identical to QuicData::AssociatedData. | 
 |   return quiche::QuicheStringPiece( | 
 |       encrypted.data(), | 
 |       GetStartOfEncryptedData(version, destination_connection_id_length, | 
 |                               source_connection_id_length, includes_version, | 
 |                               includes_diversification_nonce, | 
 |                               packet_number_length, retry_token_length_length, | 
 |                               retry_token_length, length_length)); | 
 | } | 
 |  | 
 | void QuicFramer::SetDecrypter(EncryptionLevel level, | 
 |                               std::unique_ptr<QuicDecrypter> decrypter) { | 
 |   DCHECK_EQ(alternative_decrypter_level_, NUM_ENCRYPTION_LEVELS); | 
 |   DCHECK_GE(level, decrypter_level_); | 
 |   DCHECK(!version_.KnowsWhichDecrypterToUse()); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Setting decrypter from level " | 
 |                 << EncryptionLevelToString(decrypter_level_) << " to " | 
 |                 << EncryptionLevelToString(level); | 
 |   decrypter_[decrypter_level_] = nullptr; | 
 |   decrypter_[level] = std::move(decrypter); | 
 |   decrypter_level_ = level; | 
 | } | 
 |  | 
 | void QuicFramer::SetAlternativeDecrypter( | 
 |     EncryptionLevel level, | 
 |     std::unique_ptr<QuicDecrypter> decrypter, | 
 |     bool latch_once_used) { | 
 |   DCHECK_NE(level, decrypter_level_); | 
 |   DCHECK(!version_.KnowsWhichDecrypterToUse()); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Setting alternative decrypter from level " | 
 |                 << EncryptionLevelToString(alternative_decrypter_level_) | 
 |                 << " to " << EncryptionLevelToString(level); | 
 |   if (alternative_decrypter_level_ != NUM_ENCRYPTION_LEVELS) { | 
 |     decrypter_[alternative_decrypter_level_] = nullptr; | 
 |   } | 
 |   decrypter_[level] = std::move(decrypter); | 
 |   alternative_decrypter_level_ = level; | 
 |   alternative_decrypter_latch_ = latch_once_used; | 
 | } | 
 |  | 
 | void QuicFramer::InstallDecrypter(EncryptionLevel level, | 
 |                                   std::unique_ptr<QuicDecrypter> decrypter) { | 
 |   DCHECK(version_.KnowsWhichDecrypterToUse()); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Installing decrypter at level " | 
 |                 << EncryptionLevelToString(level); | 
 |   decrypter_[level] = std::move(decrypter); | 
 | } | 
 |  | 
 | void QuicFramer::RemoveDecrypter(EncryptionLevel level) { | 
 |   DCHECK(version_.KnowsWhichDecrypterToUse()); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Removing decrypter at level " | 
 |                 << EncryptionLevelToString(level); | 
 |   decrypter_[level] = nullptr; | 
 | } | 
 |  | 
 | const QuicDecrypter* QuicFramer::GetDecrypter(EncryptionLevel level) const { | 
 |   DCHECK(version_.KnowsWhichDecrypterToUse()); | 
 |   return decrypter_[level].get(); | 
 | } | 
 |  | 
 | const QuicDecrypter* QuicFramer::decrypter() const { | 
 |   return decrypter_[decrypter_level_].get(); | 
 | } | 
 |  | 
 | const QuicDecrypter* QuicFramer::alternative_decrypter() const { | 
 |   if (alternative_decrypter_level_ == NUM_ENCRYPTION_LEVELS) { | 
 |     return nullptr; | 
 |   } | 
 |   return decrypter_[alternative_decrypter_level_].get(); | 
 | } | 
 |  | 
 | void QuicFramer::SetEncrypter(EncryptionLevel level, | 
 |                               std::unique_ptr<QuicEncrypter> encrypter) { | 
 |   DCHECK_GE(level, 0); | 
 |   DCHECK_LT(level, NUM_ENCRYPTION_LEVELS); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Setting encrypter at level " | 
 |                 << EncryptionLevelToString(level); | 
 |   encrypter_[level] = std::move(encrypter); | 
 | } | 
 |  | 
 | void QuicFramer::RemoveEncrypter(EncryptionLevel level) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Removing encrypter of " | 
 |                 << EncryptionLevelToString(level); | 
 |   encrypter_[level] = nullptr; | 
 | } | 
 |  | 
 | void QuicFramer::SetInitialObfuscators(QuicConnectionId connection_id) { | 
 |   CrypterPair crypters; | 
 |   CryptoUtils::CreateInitialObfuscators(perspective_, version_, connection_id, | 
 |                                         &crypters); | 
 |   encrypter_[ENCRYPTION_INITIAL] = std::move(crypters.encrypter); | 
 |   decrypter_[ENCRYPTION_INITIAL] = std::move(crypters.decrypter); | 
 | } | 
 |  | 
 | size_t QuicFramer::EncryptInPlace(EncryptionLevel level, | 
 |                                   QuicPacketNumber packet_number, | 
 |                                   size_t ad_len, | 
 |                                   size_t total_len, | 
 |                                   size_t buffer_len, | 
 |                                   char* buffer) { | 
 |   DCHECK(packet_number.IsInitialized()); | 
 |   if (encrypter_[level] == nullptr) { | 
 |     QUIC_BUG << ENDPOINT | 
 |              << "Attempted to encrypt in place without encrypter at level " | 
 |              << EncryptionLevelToString(level); | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |  | 
 |   size_t output_length = 0; | 
 |   if (!encrypter_[level]->EncryptPacket( | 
 |           packet_number.ToUint64(), | 
 |           quiche::QuicheStringPiece(buffer, ad_len),  // Associated data | 
 |           quiche::QuicheStringPiece(buffer + ad_len, | 
 |                                     total_len - ad_len),  // Plaintext | 
 |           buffer + ad_len,                                // Destination buffer | 
 |           &output_length, buffer_len - ad_len)) { | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |   if (version_.HasHeaderProtection() && | 
 |       !ApplyHeaderProtection(level, buffer, ad_len + output_length, ad_len)) { | 
 |     QUIC_DLOG(ERROR) << "Applying header protection failed."; | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |  | 
 |   return ad_len + output_length; | 
 | } | 
 |  | 
 | namespace { | 
 |  | 
 | const size_t kHPSampleLen = 16; | 
 |  | 
 | constexpr bool IsLongHeader(uint8_t type_byte) { | 
 |   return (type_byte & FLAGS_LONG_HEADER) != 0; | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | bool QuicFramer::ApplyHeaderProtection(EncryptionLevel level, | 
 |                                        char* buffer, | 
 |                                        size_t buffer_len, | 
 |                                        size_t ad_len) { | 
 |   QuicDataReader buffer_reader(buffer, buffer_len); | 
 |   QuicDataWriter buffer_writer(buffer_len, buffer); | 
 |   // The sample starts 4 bytes after the start of the packet number. | 
 |   if (ad_len < last_written_packet_number_length_) { | 
 |     return false; | 
 |   } | 
 |   size_t pn_offset = ad_len - last_written_packet_number_length_; | 
 |   // Sample the ciphertext and generate the mask to use for header protection. | 
 |   size_t sample_offset = pn_offset + 4; | 
 |   QuicDataReader sample_reader(buffer, buffer_len); | 
 |   quiche::QuicheStringPiece sample; | 
 |   if (!sample_reader.Seek(sample_offset) || | 
 |       !sample_reader.ReadStringPiece(&sample, kHPSampleLen)) { | 
 |     QUIC_BUG << "Not enough bytes to sample: sample_offset " << sample_offset | 
 |              << ", sample len: " << kHPSampleLen | 
 |              << ", buffer len: " << buffer_len; | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (encrypter_[level] == nullptr) { | 
 |     QUIC_BUG | 
 |         << ENDPOINT | 
 |         << "Attempted to apply header protection without encrypter at level " | 
 |         << EncryptionLevelToString(level) << " using " << version_; | 
 |     return false; | 
 |   } | 
 |  | 
 |   std::string mask = encrypter_[level]->GenerateHeaderProtectionMask(sample); | 
 |   if (mask.empty()) { | 
 |     QUIC_BUG << "Unable to generate header protection mask."; | 
 |     return false; | 
 |   } | 
 |   QuicDataReader mask_reader(mask.data(), mask.size()); | 
 |  | 
 |   // Apply the mask to the 4 or 5 least significant bits of the first byte. | 
 |   uint8_t bitmask = 0x1f; | 
 |   uint8_t type_byte; | 
 |   if (!buffer_reader.ReadUInt8(&type_byte)) { | 
 |     return false; | 
 |   } | 
 |   QuicLongHeaderType header_type; | 
 |   if (IsLongHeader(type_byte)) { | 
 |     bitmask = 0x0f; | 
 |     if (!GetLongHeaderType(type_byte, &header_type)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   uint8_t mask_byte; | 
 |   if (!mask_reader.ReadUInt8(&mask_byte) || | 
 |       !buffer_writer.WriteUInt8(type_byte ^ (mask_byte & bitmask))) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Adjust |pn_offset| to account for the diversification nonce. | 
 |   if (IsLongHeader(type_byte) && header_type == ZERO_RTT_PROTECTED && | 
 |       perspective_ == Perspective::IS_SERVER && | 
 |       version_.handshake_protocol == PROTOCOL_QUIC_CRYPTO) { | 
 |     if (pn_offset <= kDiversificationNonceSize) { | 
 |       QUIC_BUG << "Expected diversification nonce, but not enough bytes"; | 
 |       return false; | 
 |     } | 
 |     pn_offset -= kDiversificationNonceSize; | 
 |   } | 
 |   // Advance the reader and writer to the packet number. Both the reader and | 
 |   // writer have each read/written one byte. | 
 |   if (!buffer_writer.Seek(pn_offset - 1) || | 
 |       !buffer_reader.Seek(pn_offset - 1)) { | 
 |     return false; | 
 |   } | 
 |   // Apply the rest of the mask to the packet number. | 
 |   for (size_t i = 0; i < last_written_packet_number_length_; ++i) { | 
 |     uint8_t buffer_byte; | 
 |     uint8_t mask_byte; | 
 |     if (!mask_reader.ReadUInt8(&mask_byte) || | 
 |         !buffer_reader.ReadUInt8(&buffer_byte) || | 
 |         !buffer_writer.WriteUInt8(buffer_byte ^ mask_byte)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::RemoveHeaderProtection(QuicDataReader* reader, | 
 |                                         const QuicEncryptedPacket& packet, | 
 |                                         QuicPacketHeader* header, | 
 |                                         uint64_t* full_packet_number, | 
 |                                         std::vector<char>* associated_data) { | 
 |   EncryptionLevel expected_decryption_level = GetEncryptionLevel(*header); | 
 |   QuicDecrypter* decrypter = decrypter_[expected_decryption_level].get(); | 
 |   if (decrypter == nullptr) { | 
 |     QUIC_DVLOG(1) | 
 |         << ENDPOINT | 
 |         << "No decrypter available for removing header protection at level " | 
 |         << EncryptionLevelToString(expected_decryption_level); | 
 |     return false; | 
 |   } | 
 |  | 
 |   bool has_diversification_nonce = | 
 |       header->form == IETF_QUIC_LONG_HEADER_PACKET && | 
 |       header->long_packet_type == ZERO_RTT_PROTECTED && | 
 |       perspective_ == Perspective::IS_CLIENT && | 
 |       version_.handshake_protocol == PROTOCOL_QUIC_CRYPTO; | 
 |  | 
 |   // Read a sample from the ciphertext and compute the mask to use for header | 
 |   // protection. | 
 |   quiche::QuicheStringPiece remaining_packet = reader->PeekRemainingPayload(); | 
 |   QuicDataReader sample_reader(remaining_packet); | 
 |  | 
 |   // The sample starts 4 bytes after the start of the packet number. | 
 |   quiche::QuicheStringPiece pn; | 
 |   if (!sample_reader.ReadStringPiece(&pn, 4)) { | 
 |     QUIC_DVLOG(1) << "Not enough data to sample"; | 
 |     return false; | 
 |   } | 
 |   if (has_diversification_nonce) { | 
 |     // In Google QUIC, the diversification nonce comes between the packet number | 
 |     // and the sample. | 
 |     if (!sample_reader.Seek(kDiversificationNonceSize)) { | 
 |       QUIC_DVLOG(1) << "No diversification nonce to skip over"; | 
 |       return false; | 
 |     } | 
 |   } | 
 |   std::string mask = decrypter->GenerateHeaderProtectionMask(&sample_reader); | 
 |   QuicDataReader mask_reader(mask.data(), mask.size()); | 
 |   if (mask.empty()) { | 
 |     QUIC_DVLOG(1) << "Failed to compute mask"; | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Unmask the rest of the type byte. | 
 |   uint8_t bitmask = 0x1f; | 
 |   if (IsLongHeader(header->type_byte)) { | 
 |     bitmask = 0x0f; | 
 |   } | 
 |   uint8_t mask_byte; | 
 |   if (!mask_reader.ReadUInt8(&mask_byte)) { | 
 |     QUIC_DVLOG(1) << "No first byte to read from mask"; | 
 |     return false; | 
 |   } | 
 |   header->type_byte ^= (mask_byte & bitmask); | 
 |  | 
 |   // Compute the packet number length. | 
 |   header->packet_number_length = | 
 |       static_cast<QuicPacketNumberLength>((header->type_byte & 0x03) + 1); | 
 |  | 
 |   char pn_buffer[IETF_MAX_PACKET_NUMBER_LENGTH] = {}; | 
 |   QuicDataWriter pn_writer(QUICHE_ARRAYSIZE(pn_buffer), pn_buffer); | 
 |  | 
 |   // Read the (protected) packet number from the reader and unmask the packet | 
 |   // number. | 
 |   for (size_t i = 0; i < header->packet_number_length; ++i) { | 
 |     uint8_t protected_pn_byte, mask_byte; | 
 |     if (!mask_reader.ReadUInt8(&mask_byte) || | 
 |         !reader->ReadUInt8(&protected_pn_byte) || | 
 |         !pn_writer.WriteUInt8(protected_pn_byte ^ mask_byte)) { | 
 |       QUIC_DVLOG(1) << "Failed to unmask packet number"; | 
 |       return false; | 
 |     } | 
 |   } | 
 |   QuicDataReader packet_number_reader(pn_writer.data(), pn_writer.length()); | 
 |   QuicPacketNumber base_packet_number; | 
 |   if (supports_multiple_packet_number_spaces_) { | 
 |     PacketNumberSpace pn_space = GetPacketNumberSpace(*header); | 
 |     if (pn_space == NUM_PACKET_NUMBER_SPACES) { | 
 |       return false; | 
 |     } | 
 |     base_packet_number = largest_decrypted_packet_numbers_[pn_space]; | 
 |   } else { | 
 |     base_packet_number = largest_packet_number_; | 
 |   } | 
 |   if (!ProcessAndCalculatePacketNumber( | 
 |           &packet_number_reader, header->packet_number_length, | 
 |           base_packet_number, full_packet_number)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Get the associated data, and apply the same unmasking operations to it. | 
 |   quiche::QuicheStringPiece ad = GetAssociatedDataFromEncryptedPacket( | 
 |       version_.transport_version, packet, | 
 |       GetIncludedDestinationConnectionIdLength(*header), | 
 |       GetIncludedSourceConnectionIdLength(*header), header->version_flag, | 
 |       has_diversification_nonce, header->packet_number_length, | 
 |       header->retry_token_length_length, header->retry_token.length(), | 
 |       header->length_length); | 
 |   *associated_data = std::vector<char>(ad.begin(), ad.end()); | 
 |   QuicDataWriter ad_writer(associated_data->size(), associated_data->data()); | 
 |  | 
 |   // Apply the unmasked type byte and packet number to |associated_data|. | 
 |   if (!ad_writer.WriteUInt8(header->type_byte)) { | 
 |     return false; | 
 |   } | 
 |   // Put the packet number at the end of the AD, or if there's a diversification | 
 |   // nonce, before that (which is at the end of the AD). | 
 |   size_t seek_len = ad_writer.remaining() - header->packet_number_length; | 
 |   if (has_diversification_nonce) { | 
 |     seek_len -= kDiversificationNonceSize; | 
 |   } | 
 |   if (!ad_writer.Seek(seek_len) || | 
 |       !ad_writer.WriteBytes(pn_writer.data(), pn_writer.length())) { | 
 |     QUIC_DVLOG(1) << "Failed to apply unmasking operations to AD"; | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | size_t QuicFramer::EncryptPayload(EncryptionLevel level, | 
 |                                   QuicPacketNumber packet_number, | 
 |                                   const QuicPacket& packet, | 
 |                                   char* buffer, | 
 |                                   size_t buffer_len) { | 
 |   DCHECK(packet_number.IsInitialized()); | 
 |   if (encrypter_[level] == nullptr) { | 
 |     QUIC_BUG << ENDPOINT << "Attempted to encrypt without encrypter at level " | 
 |              << EncryptionLevelToString(level); | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece associated_data = | 
 |       packet.AssociatedData(version_.transport_version); | 
 |   // Copy in the header, because the encrypter only populates the encrypted | 
 |   // plaintext content. | 
 |   const size_t ad_len = associated_data.length(); | 
 |   memmove(buffer, associated_data.data(), ad_len); | 
 |   // Encrypt the plaintext into the buffer. | 
 |   size_t output_length = 0; | 
 |   if (!encrypter_[level]->EncryptPacket( | 
 |           packet_number.ToUint64(), associated_data, | 
 |           packet.Plaintext(version_.transport_version), buffer + ad_len, | 
 |           &output_length, buffer_len - ad_len)) { | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |   if (version_.HasHeaderProtection() && | 
 |       !ApplyHeaderProtection(level, buffer, ad_len + output_length, ad_len)) { | 
 |     QUIC_DLOG(ERROR) << "Applying header protection failed."; | 
 |     RaiseError(QUIC_ENCRYPTION_FAILURE); | 
 |     return 0; | 
 |   } | 
 |  | 
 |   return ad_len + output_length; | 
 | } | 
 |  | 
 | size_t QuicFramer::GetCiphertextSize(EncryptionLevel level, | 
 |                                      size_t plaintext_size) const { | 
 |   if (encrypter_[level] == nullptr) { | 
 |     QUIC_BUG << ENDPOINT | 
 |              << "Attempted to get ciphertext size without encrypter at level " | 
 |              << EncryptionLevelToString(level) << " using " << version_; | 
 |     return plaintext_size; | 
 |   } | 
 |   return encrypter_[level]->GetCiphertextSize(plaintext_size); | 
 | } | 
 |  | 
 | size_t QuicFramer::GetMaxPlaintextSize(size_t ciphertext_size) { | 
 |   // In order to keep the code simple, we don't have the current encryption | 
 |   // level to hand. Both the NullEncrypter and AES-GCM have a tag length of 12. | 
 |   size_t min_plaintext_size = ciphertext_size; | 
 |  | 
 |   for (int i = ENCRYPTION_INITIAL; i < NUM_ENCRYPTION_LEVELS; i++) { | 
 |     if (encrypter_[i] != nullptr) { | 
 |       size_t size = encrypter_[i]->GetMaxPlaintextSize(ciphertext_size); | 
 |       if (size < min_plaintext_size) { | 
 |         min_plaintext_size = size; | 
 |       } | 
 |     } | 
 |   } | 
 |  | 
 |   return min_plaintext_size; | 
 | } | 
 |  | 
 | bool QuicFramer::DecryptPayload(quiche::QuicheStringPiece encrypted, | 
 |                                 quiche::QuicheStringPiece associated_data, | 
 |                                 const QuicPacketHeader& header, | 
 |                                 char* decrypted_buffer, | 
 |                                 size_t buffer_length, | 
 |                                 size_t* decrypted_length, | 
 |                                 EncryptionLevel* decrypted_level) { | 
 |   if (!EncryptionLevelIsValid(decrypter_level_)) { | 
 |     QUIC_BUG << "Attempted to decrypt with bad decrypter_level_"; | 
 |     return false; | 
 |   } | 
 |   EncryptionLevel level = decrypter_level_; | 
 |   QuicDecrypter* decrypter = decrypter_[level].get(); | 
 |   QuicDecrypter* alternative_decrypter = nullptr; | 
 |   if (version().KnowsWhichDecrypterToUse()) { | 
 |     if (header.form == GOOGLE_QUIC_PACKET) { | 
 |       QUIC_BUG << "Attempted to decrypt GOOGLE_QUIC_PACKET with a version that " | 
 |                   "knows which decrypter to use"; | 
 |       return false; | 
 |     } | 
 |     level = GetEncryptionLevel(header); | 
 |     if (!EncryptionLevelIsValid(level)) { | 
 |       QUIC_BUG << "Attempted to decrypt with bad level"; | 
 |       return false; | 
 |     } | 
 |     decrypter = decrypter_[level].get(); | 
 |     if (decrypter == nullptr) { | 
 |       return false; | 
 |     } | 
 |     if (level == ENCRYPTION_ZERO_RTT && | 
 |         perspective_ == Perspective::IS_CLIENT && header.nonce != nullptr) { | 
 |       decrypter->SetDiversificationNonce(*header.nonce); | 
 |     } | 
 |   } else if (alternative_decrypter_level_ != NUM_ENCRYPTION_LEVELS) { | 
 |     if (!EncryptionLevelIsValid(alternative_decrypter_level_)) { | 
 |       QUIC_BUG << "Attempted to decrypt with bad alternative_decrypter_level_"; | 
 |       return false; | 
 |     } | 
 |     alternative_decrypter = decrypter_[alternative_decrypter_level_].get(); | 
 |   } | 
 |  | 
 |   if (decrypter == nullptr) { | 
 |     QUIC_BUG << "Attempting to decrypt without decrypter, encryption level:" | 
 |              << level << " version:" << version(); | 
 |     return false; | 
 |   } | 
 |  | 
 |   bool success = decrypter->DecryptPacket( | 
 |       header.packet_number.ToUint64(), associated_data, encrypted, | 
 |       decrypted_buffer, decrypted_length, buffer_length); | 
 |   if (success) { | 
 |     visitor_->OnDecryptedPacket(level); | 
 |     *decrypted_level = level; | 
 |   } else if (alternative_decrypter != nullptr) { | 
 |     if (header.nonce != nullptr) { | 
 |       DCHECK_EQ(perspective_, Perspective::IS_CLIENT); | 
 |       alternative_decrypter->SetDiversificationNonce(*header.nonce); | 
 |     } | 
 |     bool try_alternative_decryption = true; | 
 |     if (alternative_decrypter_level_ == ENCRYPTION_ZERO_RTT) { | 
 |       if (perspective_ == Perspective::IS_CLIENT) { | 
 |         if (header.nonce == nullptr) { | 
 |           // Can not use INITIAL decryption without a diversification nonce. | 
 |           try_alternative_decryption = false; | 
 |         } | 
 |       } else { | 
 |         DCHECK(header.nonce == nullptr); | 
 |       } | 
 |     } | 
 |  | 
 |     if (try_alternative_decryption) { | 
 |       success = alternative_decrypter->DecryptPacket( | 
 |           header.packet_number.ToUint64(), associated_data, encrypted, | 
 |           decrypted_buffer, decrypted_length, buffer_length); | 
 |     } | 
 |     if (success) { | 
 |       visitor_->OnDecryptedPacket(alternative_decrypter_level_); | 
 |       *decrypted_level = decrypter_level_; | 
 |       if (alternative_decrypter_latch_) { | 
 |         if (!EncryptionLevelIsValid(alternative_decrypter_level_)) { | 
 |           QUIC_BUG << "Attempted to latch alternate decrypter with bad " | 
 |                       "alternative_decrypter_level_"; | 
 |           return false; | 
 |         } | 
 |         // Switch to the alternative decrypter and latch so that we cannot | 
 |         // switch back. | 
 |         decrypter_level_ = alternative_decrypter_level_; | 
 |         alternative_decrypter_level_ = NUM_ENCRYPTION_LEVELS; | 
 |       } else { | 
 |         // Switch the alternative decrypter so that we use it first next time. | 
 |         EncryptionLevel level = alternative_decrypter_level_; | 
 |         alternative_decrypter_level_ = decrypter_level_; | 
 |         decrypter_level_ = level; | 
 |       } | 
 |     } | 
 |   } | 
 |  | 
 |   if (!success) { | 
 |     QUIC_DVLOG(1) << ENDPOINT << "DecryptPacket failed for: " << header; | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | size_t QuicFramer::GetIetfAckFrameSize(const QuicAckFrame& frame) { | 
 |   // Type byte, largest_acked, and delay_time are straight-forward. | 
 |   size_t ack_frame_size = kQuicFrameTypeSize; | 
 |   QuicPacketNumber largest_acked = LargestAcked(frame); | 
 |   ack_frame_size += QuicDataWriter::GetVarInt62Len(largest_acked.ToUint64()); | 
 |   uint64_t ack_delay_time_us; | 
 |   ack_delay_time_us = frame.ack_delay_time.ToMicroseconds(); | 
 |   ack_delay_time_us = ack_delay_time_us >> local_ack_delay_exponent_; | 
 |   ack_frame_size += QuicDataWriter::GetVarInt62Len(ack_delay_time_us); | 
 |  | 
 |   if (frame.packets.Empty() || frame.packets.Max() != largest_acked) { | 
 |     QUIC_BUG << "Malformed ack frame"; | 
 |     // ACK frame serialization will fail and connection will be closed. | 
 |     return ack_frame_size; | 
 |   } | 
 |  | 
 |   // Ack block count. | 
 |   ack_frame_size += | 
 |       QuicDataWriter::GetVarInt62Len(frame.packets.NumIntervals() - 1); | 
 |  | 
 |   // First Ack range. | 
 |   auto iter = frame.packets.rbegin(); | 
 |   ack_frame_size += QuicDataWriter::GetVarInt62Len(iter->Length() - 1); | 
 |   QuicPacketNumber previous_smallest = iter->min(); | 
 |   ++iter; | 
 |  | 
 |   // Ack blocks. | 
 |   for (; iter != frame.packets.rend(); ++iter) { | 
 |     const uint64_t gap = previous_smallest - iter->max() - 1; | 
 |     const uint64_t ack_range = iter->Length() - 1; | 
 |     ack_frame_size += (QuicDataWriter::GetVarInt62Len(gap) + | 
 |                        QuicDataWriter::GetVarInt62Len(ack_range)); | 
 |     previous_smallest = iter->min(); | 
 |   } | 
 |  | 
 |   // ECN counts. | 
 |   if (frame.ecn_counters_populated && | 
 |       (frame.ect_0_count || frame.ect_1_count || frame.ecn_ce_count)) { | 
 |     ack_frame_size += QuicDataWriter::GetVarInt62Len(frame.ect_0_count); | 
 |     ack_frame_size += QuicDataWriter::GetVarInt62Len(frame.ect_1_count); | 
 |     ack_frame_size += QuicDataWriter::GetVarInt62Len(frame.ecn_ce_count); | 
 |   } | 
 |  | 
 |   return ack_frame_size; | 
 | } | 
 |  | 
 | size_t QuicFramer::GetAckFrameSize( | 
 |     const QuicAckFrame& ack, | 
 |     QuicPacketNumberLength /*packet_number_length*/) { | 
 |   DCHECK(!ack.packets.Empty()); | 
 |   size_t ack_size = 0; | 
 |  | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return GetIetfAckFrameSize(ack); | 
 |   } | 
 |   AckFrameInfo ack_info = GetAckFrameInfo(ack); | 
 |   QuicPacketNumberLength ack_block_length = | 
 |       GetMinPacketNumberLength(QuicPacketNumber(ack_info.max_block_length)); | 
 |  | 
 |   ack_size = GetMinAckFrameSize(version_.transport_version, ack, | 
 |                                 local_ack_delay_exponent_); | 
 |   // First ack block length. | 
 |   ack_size += ack_block_length; | 
 |   if (ack_info.num_ack_blocks != 0) { | 
 |     ack_size += kNumberOfAckBlocksSize; | 
 |     ack_size += std::min(ack_info.num_ack_blocks, kMaxAckBlocks) * | 
 |                 (ack_block_length + PACKET_1BYTE_PACKET_NUMBER); | 
 |   } | 
 |  | 
 |   // Include timestamps. | 
 |   if (process_timestamps_) { | 
 |     ack_size += GetAckFrameTimeStampSize(ack); | 
 |   } | 
 |  | 
 |   return ack_size; | 
 | } | 
 |  | 
 | size_t QuicFramer::GetAckFrameTimeStampSize(const QuicAckFrame& ack) { | 
 |   if (ack.received_packet_times.empty()) { | 
 |     return 0; | 
 |   } | 
 |  | 
 |   return kQuicNumTimestampsLength + kQuicFirstTimestampLength + | 
 |          (kQuicTimestampLength + kQuicTimestampPacketNumberGapLength) * | 
 |              (ack.received_packet_times.size() - 1); | 
 | } | 
 |  | 
 | size_t QuicFramer::ComputeFrameLength( | 
 |     const QuicFrame& frame, | 
 |     bool last_frame_in_packet, | 
 |     QuicPacketNumberLength packet_number_length) { | 
 |   switch (frame.type) { | 
 |     case STREAM_FRAME: | 
 |       return GetMinStreamFrameSize( | 
 |                  version_.transport_version, frame.stream_frame.stream_id, | 
 |                  frame.stream_frame.offset, last_frame_in_packet, | 
 |                  frame.stream_frame.data_length) + | 
 |              frame.stream_frame.data_length; | 
 |     case CRYPTO_FRAME: | 
 |       return GetMinCryptoFrameSize(frame.crypto_frame->offset, | 
 |                                    frame.crypto_frame->data_length) + | 
 |              frame.crypto_frame->data_length; | 
 |     case ACK_FRAME: { | 
 |       return GetAckFrameSize(*frame.ack_frame, packet_number_length); | 
 |     } | 
 |     case STOP_WAITING_FRAME: | 
 |       return GetStopWaitingFrameSize(packet_number_length); | 
 |     case MTU_DISCOVERY_FRAME: | 
 |       // MTU discovery frames are serialized as ping frames. | 
 |       return kQuicFrameTypeSize; | 
 |     case MESSAGE_FRAME: | 
 |       return GetMessageFrameSize(version_.transport_version, | 
 |                                  last_frame_in_packet, | 
 |                                  frame.message_frame->message_length); | 
 |     case PADDING_FRAME: | 
 |       DCHECK(false); | 
 |       return 0; | 
 |     default: | 
 |       return GetRetransmittableControlFrameSize(version_.transport_version, | 
 |                                                 frame); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicFramer::AppendTypeByte(const QuicFrame& frame, | 
 |                                 bool last_frame_in_packet, | 
 |                                 QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return AppendIetfTypeByte(frame, last_frame_in_packet, writer); | 
 |   } | 
 |   uint8_t type_byte = 0; | 
 |   switch (frame.type) { | 
 |     case STREAM_FRAME: | 
 |       type_byte = | 
 |           GetStreamFrameTypeByte(frame.stream_frame, last_frame_in_packet); | 
 |       break; | 
 |     case ACK_FRAME: | 
 |       return true; | 
 |     case MTU_DISCOVERY_FRAME: | 
 |       type_byte = static_cast<uint8_t>(PING_FRAME); | 
 |       break; | 
 |     case NEW_CONNECTION_ID_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append NEW_CONNECTION_ID frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case RETIRE_CONNECTION_ID_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append RETIRE_CONNECTION_ID frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case NEW_TOKEN_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append NEW_TOKEN frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case MAX_STREAMS_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append MAX_STREAMS frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case STREAMS_BLOCKED_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append STREAMS_BLOCKED frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case PATH_RESPONSE_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append PATH_RESPONSE frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case PATH_CHALLENGE_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append PATH_CHALLENGE frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case STOP_SENDING_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append STOP_SENDING frame and not in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case MESSAGE_FRAME: | 
 |       return true; | 
 |  | 
 |     default: | 
 |       type_byte = static_cast<uint8_t>(frame.type); | 
 |       break; | 
 |   } | 
 |  | 
 |   return writer->WriteUInt8(type_byte); | 
 | } | 
 |  | 
 | bool QuicFramer::AppendIetfTypeByte(const QuicFrame& frame, | 
 |                                     bool last_frame_in_packet, | 
 |                                     QuicDataWriter* writer) { | 
 |   uint8_t type_byte = 0; | 
 |   switch (frame.type) { | 
 |     case PADDING_FRAME: | 
 |       type_byte = IETF_PADDING; | 
 |       break; | 
 |     case RST_STREAM_FRAME: | 
 |       type_byte = IETF_RST_STREAM; | 
 |       break; | 
 |     case CONNECTION_CLOSE_FRAME: | 
 |       switch (frame.connection_close_frame->close_type) { | 
 |         case IETF_QUIC_APPLICATION_CONNECTION_CLOSE: | 
 |           type_byte = IETF_APPLICATION_CLOSE; | 
 |           break; | 
 |         case IETF_QUIC_TRANSPORT_CONNECTION_CLOSE: | 
 |           type_byte = IETF_CONNECTION_CLOSE; | 
 |           break; | 
 |         default: | 
 |           set_detailed_error("Invalid QuicConnectionCloseFrame type."); | 
 |           return RaiseError(QUIC_INTERNAL_ERROR); | 
 |       } | 
 |       break; | 
 |     case GOAWAY_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to create non-IETF QUIC GOAWAY frame in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case WINDOW_UPDATE_FRAME: | 
 |       // Depending on whether there is a stream ID or not, will be either a | 
 |       // MAX_STREAM_DATA frame or a MAX_DATA frame. | 
 |       if (frame.window_update_frame->stream_id == | 
 |           QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |         type_byte = IETF_MAX_DATA; | 
 |       } else { | 
 |         type_byte = IETF_MAX_STREAM_DATA; | 
 |       } | 
 |       break; | 
 |     case BLOCKED_FRAME: | 
 |       if (frame.blocked_frame->stream_id == | 
 |           QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |         type_byte = IETF_DATA_BLOCKED; | 
 |       } else { | 
 |         type_byte = IETF_STREAM_DATA_BLOCKED; | 
 |       } | 
 |       break; | 
 |     case STOP_WAITING_FRAME: | 
 |       set_detailed_error( | 
 |           "Attempt to append type byte of STOP WAITING frame in IETF QUIC."); | 
 |       return RaiseError(QUIC_INTERNAL_ERROR); | 
 |     case PING_FRAME: | 
 |       type_byte = IETF_PING; | 
 |       break; | 
 |     case STREAM_FRAME: | 
 |       type_byte = | 
 |           GetStreamFrameTypeByte(frame.stream_frame, last_frame_in_packet); | 
 |       break; | 
 |     case ACK_FRAME: | 
 |       // Do nothing here, AppendIetfAckFrameAndTypeByte() will put the type byte | 
 |       // in the buffer. | 
 |       return true; | 
 |     case MTU_DISCOVERY_FRAME: | 
 |       // The path MTU discovery frame is encoded as a PING frame on the wire. | 
 |       type_byte = IETF_PING; | 
 |       break; | 
 |     case NEW_CONNECTION_ID_FRAME: | 
 |       type_byte = IETF_NEW_CONNECTION_ID; | 
 |       break; | 
 |     case RETIRE_CONNECTION_ID_FRAME: | 
 |       type_byte = IETF_RETIRE_CONNECTION_ID; | 
 |       break; | 
 |     case NEW_TOKEN_FRAME: | 
 |       type_byte = IETF_NEW_TOKEN; | 
 |       break; | 
 |     case MAX_STREAMS_FRAME: | 
 |       if (frame.max_streams_frame.unidirectional) { | 
 |         type_byte = IETF_MAX_STREAMS_UNIDIRECTIONAL; | 
 |       } else { | 
 |         type_byte = IETF_MAX_STREAMS_BIDIRECTIONAL; | 
 |       } | 
 |       break; | 
 |     case STREAMS_BLOCKED_FRAME: | 
 |       if (frame.streams_blocked_frame.unidirectional) { | 
 |         type_byte = IETF_STREAMS_BLOCKED_UNIDIRECTIONAL; | 
 |       } else { | 
 |         type_byte = IETF_STREAMS_BLOCKED_BIDIRECTIONAL; | 
 |       } | 
 |       break; | 
 |     case PATH_RESPONSE_FRAME: | 
 |       type_byte = IETF_PATH_RESPONSE; | 
 |       break; | 
 |     case PATH_CHALLENGE_FRAME: | 
 |       type_byte = IETF_PATH_CHALLENGE; | 
 |       break; | 
 |     case STOP_SENDING_FRAME: | 
 |       type_byte = IETF_STOP_SENDING; | 
 |       break; | 
 |     case MESSAGE_FRAME: | 
 |       return true; | 
 |     case CRYPTO_FRAME: | 
 |       type_byte = IETF_CRYPTO; | 
 |       break; | 
 |     case HANDSHAKE_DONE_FRAME: | 
 |       type_byte = IETF_HANDSHAKE_DONE; | 
 |       break; | 
 |     default: | 
 |       QUIC_BUG << "Attempt to generate a frame type for an unsupported value: " | 
 |                << frame.type; | 
 |       return false; | 
 |   } | 
 |   return writer->WriteUInt8(type_byte); | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::AppendPacketNumber(QuicPacketNumberLength packet_number_length, | 
 |                                     QuicPacketNumber packet_number, | 
 |                                     QuicDataWriter* writer) { | 
 |   DCHECK(packet_number.IsInitialized()); | 
 |   if (!IsValidPacketNumberLength(packet_number_length)) { | 
 |     QUIC_BUG << "Invalid packet_number_length: " << packet_number_length; | 
 |     return false; | 
 |   } | 
 |   return writer->WriteBytesToUInt64(packet_number_length, | 
 |                                     packet_number.ToUint64()); | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::AppendStreamId(size_t stream_id_length, | 
 |                                 QuicStreamId stream_id, | 
 |                                 QuicDataWriter* writer) { | 
 |   if (stream_id_length == 0 || stream_id_length > 4) { | 
 |     QUIC_BUG << "Invalid stream_id_length: " << stream_id_length; | 
 |     return false; | 
 |   } | 
 |   return writer->WriteBytesToUInt64(stream_id_length, stream_id); | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::AppendStreamOffset(size_t offset_length, | 
 |                                     QuicStreamOffset offset, | 
 |                                     QuicDataWriter* writer) { | 
 |   if (offset_length == 1 || offset_length > 8) { | 
 |     QUIC_BUG << "Invalid stream_offset_length: " << offset_length; | 
 |     return false; | 
 |   } | 
 |  | 
 |   return writer->WriteBytesToUInt64(offset_length, offset); | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::AppendAckBlock(uint8_t gap, | 
 |                                 QuicPacketNumberLength length_length, | 
 |                                 uint64_t length, | 
 |                                 QuicDataWriter* writer) { | 
 |   if (length == 0) { | 
 |     if (!IsValidPacketNumberLength(length_length)) { | 
 |       QUIC_BUG << "Invalid packet_number_length: " << length_length; | 
 |       return false; | 
 |     } | 
 |     return writer->WriteUInt8(gap) && | 
 |            writer->WriteBytesToUInt64(length_length, length); | 
 |   } | 
 |   return writer->WriteUInt8(gap) && | 
 |          AppendPacketNumber(length_length, QuicPacketNumber(length), writer); | 
 | } | 
 |  | 
 | bool QuicFramer::AppendStreamFrame(const QuicStreamFrame& frame, | 
 |                                    bool no_stream_frame_length, | 
 |                                    QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return AppendIetfStreamFrame(frame, no_stream_frame_length, writer); | 
 |   } | 
 |   if (!AppendStreamId(GetStreamIdSize(frame.stream_id), frame.stream_id, | 
 |                       writer)) { | 
 |     QUIC_BUG << "Writing stream id size failed."; | 
 |     return false; | 
 |   } | 
 |   if (!AppendStreamOffset(GetStreamOffsetSize(frame.offset), frame.offset, | 
 |                           writer)) { | 
 |     QUIC_BUG << "Writing offset size failed."; | 
 |     return false; | 
 |   } | 
 |   if (!no_stream_frame_length) { | 
 |     static_assert( | 
 |         std::numeric_limits<decltype(frame.data_length)>::max() <= | 
 |             std::numeric_limits<uint16_t>::max(), | 
 |         "If frame.data_length can hold more than a uint16_t than we need to " | 
 |         "check that frame.data_length <= std::numeric_limits<uint16_t>::max()"); | 
 |     if (!writer->WriteUInt16(static_cast<uint16_t>(frame.data_length))) { | 
 |       QUIC_BUG << "Writing stream frame length failed"; | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   if (data_producer_ != nullptr) { | 
 |     DCHECK_EQ(nullptr, frame.data_buffer); | 
 |     if (frame.data_length == 0) { | 
 |       return true; | 
 |     } | 
 |     if (data_producer_->WriteStreamData(frame.stream_id, frame.offset, | 
 |                                         frame.data_length, | 
 |                                         writer) != WRITE_SUCCESS) { | 
 |       QUIC_BUG << "Writing frame data failed."; | 
 |       return false; | 
 |     } | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (!writer->WriteBytes(frame.data_buffer, frame.data_length)) { | 
 |     QUIC_BUG << "Writing frame data failed."; | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendNewTokenFrame(const QuicNewTokenFrame& frame, | 
 |                                      QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.token.length()))) { | 
 |     set_detailed_error("Writing token length failed."); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteBytes(frame.token.data(), frame.token.length())) { | 
 |     set_detailed_error("Writing token buffer failed."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessNewTokenFrame(QuicDataReader* reader, | 
 |                                       QuicNewTokenFrame* frame) { | 
 |   uint64_t length; | 
 |   if (!reader->ReadVarInt62(&length)) { | 
 |     set_detailed_error("Unable to read new token length."); | 
 |     return false; | 
 |   } | 
 |   if (length > kMaxNewTokenTokenLength) { | 
 |     set_detailed_error("Token length larger than maximum."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // TODO(ianswett): Don't use quiche::QuicheStringPiece as an intermediary. | 
 |   quiche::QuicheStringPiece data; | 
 |   if (!reader->ReadStringPiece(&data, length)) { | 
 |     set_detailed_error("Unable to read new token data."); | 
 |     return false; | 
 |   } | 
 |   frame->token = std::string(data); | 
 |   return true; | 
 | } | 
 |  | 
 | // Add a new ietf-format stream frame. | 
 | // Bits controlling whether there is a frame-length and frame-offset | 
 | // are in the QuicStreamFrame. | 
 | bool QuicFramer::AppendIetfStreamFrame(const QuicStreamFrame& frame, | 
 |                                        bool last_frame_in_packet, | 
 |                                        QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.stream_id))) { | 
 |     set_detailed_error("Writing stream id failed."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (frame.offset != 0) { | 
 |     if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.offset))) { | 
 |       set_detailed_error("Writing data offset failed."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   if (!last_frame_in_packet) { | 
 |     if (!writer->WriteVarInt62(frame.data_length)) { | 
 |       set_detailed_error("Writing data length failed."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   if (frame.data_length == 0) { | 
 |     return true; | 
 |   } | 
 |   if (data_producer_ == nullptr) { | 
 |     if (!writer->WriteBytes(frame.data_buffer, frame.data_length)) { | 
 |       set_detailed_error("Writing frame data failed."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     DCHECK_EQ(nullptr, frame.data_buffer); | 
 |  | 
 |     if (data_producer_->WriteStreamData(frame.stream_id, frame.offset, | 
 |                                         frame.data_length, | 
 |                                         writer) != WRITE_SUCCESS) { | 
 |       set_detailed_error("Writing frame data failed."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendCryptoFrame(const QuicCryptoFrame& frame, | 
 |                                    QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.offset))) { | 
 |     set_detailed_error("Writing data offset failed."); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.data_length))) { | 
 |     set_detailed_error("Writing data length failed."); | 
 |     return false; | 
 |   } | 
 |   if (data_producer_ == nullptr) { | 
 |     if (frame.data_buffer == nullptr || | 
 |         !writer->WriteBytes(frame.data_buffer, frame.data_length)) { | 
 |       set_detailed_error("Writing frame data failed."); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     DCHECK_EQ(nullptr, frame.data_buffer); | 
 |     if (!data_producer_->WriteCryptoData(frame.level, frame.offset, | 
 |                                          frame.data_length, writer)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicFramer::set_version(const ParsedQuicVersion version) { | 
 |   DCHECK(IsSupportedVersion(version)) << ParsedQuicVersionToString(version); | 
 |   version_ = version; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendAckFrameAndTypeByte(const QuicAckFrame& frame, | 
 |                                            QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return AppendIetfAckFrameAndTypeByte(frame, writer); | 
 |   } | 
 |  | 
 |   const AckFrameInfo new_ack_info = GetAckFrameInfo(frame); | 
 |   QuicPacketNumber largest_acked = LargestAcked(frame); | 
 |   QuicPacketNumberLength largest_acked_length = | 
 |       GetMinPacketNumberLength(largest_acked); | 
 |   QuicPacketNumberLength ack_block_length = | 
 |       GetMinPacketNumberLength(QuicPacketNumber(new_ack_info.max_block_length)); | 
 |   // Calculate available bytes for timestamps and ack blocks. | 
 |   int32_t available_timestamp_and_ack_block_bytes = | 
 |       writer->capacity() - writer->length() - ack_block_length - | 
 |       GetMinAckFrameSize(version_.transport_version, frame, | 
 |                          local_ack_delay_exponent_) - | 
 |       (new_ack_info.num_ack_blocks != 0 ? kNumberOfAckBlocksSize : 0); | 
 |   DCHECK_LE(0, available_timestamp_and_ack_block_bytes); | 
 |  | 
 |   uint8_t type_byte = 0; | 
 |   SetBit(&type_byte, new_ack_info.num_ack_blocks != 0, | 
 |          kQuicHasMultipleAckBlocksOffset); | 
 |  | 
 |   SetBits(&type_byte, GetPacketNumberFlags(largest_acked_length), | 
 |           kQuicSequenceNumberLengthNumBits, kLargestAckedOffset); | 
 |  | 
 |   SetBits(&type_byte, GetPacketNumberFlags(ack_block_length), | 
 |           kQuicSequenceNumberLengthNumBits, kActBlockLengthOffset); | 
 |  | 
 |   type_byte |= kQuicFrameTypeAckMask; | 
 |  | 
 |   if (!writer->WriteUInt8(type_byte)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   size_t max_num_ack_blocks = available_timestamp_and_ack_block_bytes / | 
 |                               (ack_block_length + PACKET_1BYTE_PACKET_NUMBER); | 
 |  | 
 |   // Number of ack blocks. | 
 |   size_t num_ack_blocks = | 
 |       std::min(new_ack_info.num_ack_blocks, max_num_ack_blocks); | 
 |   if (num_ack_blocks > std::numeric_limits<uint8_t>::max()) { | 
 |     num_ack_blocks = std::numeric_limits<uint8_t>::max(); | 
 |   } | 
 |  | 
 |   // Largest acked. | 
 |   if (!AppendPacketNumber(largest_acked_length, largest_acked, writer)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Largest acked delta time. | 
 |   uint64_t ack_delay_time_us = kUFloat16MaxValue; | 
 |   if (!frame.ack_delay_time.IsInfinite()) { | 
 |     DCHECK_LE(0u, frame.ack_delay_time.ToMicroseconds()); | 
 |     ack_delay_time_us = frame.ack_delay_time.ToMicroseconds(); | 
 |   } | 
 |   if (!writer->WriteUFloat16(ack_delay_time_us)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (num_ack_blocks > 0) { | 
 |     if (!writer->WriteBytes(&num_ack_blocks, 1)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   // First ack block length. | 
 |   if (!AppendPacketNumber(ack_block_length, | 
 |                           QuicPacketNumber(new_ack_info.first_block_length), | 
 |                           writer)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Ack blocks. | 
 |   if (num_ack_blocks > 0) { | 
 |     size_t num_ack_blocks_written = 0; | 
 |     // Append, in descending order from the largest ACKed packet, a series of | 
 |     // ACK blocks that represents the successfully acknoweldged packets. Each | 
 |     // appended gap/block length represents a descending delta from the previous | 
 |     // block. i.e.: | 
 |     // |--- length ---|--- gap ---|--- length ---|--- gap ---|--- largest ---| | 
 |     // For gaps larger than can be represented by a single encoded gap, a 0 | 
 |     // length gap of the maximum is used, i.e.: | 
 |     // |--- length ---|--- gap ---|- 0 -|--- gap ---|--- largest ---| | 
 |     auto itr = frame.packets.rbegin(); | 
 |     QuicPacketNumber previous_start = itr->min(); | 
 |     ++itr; | 
 |  | 
 |     for (; | 
 |          itr != frame.packets.rend() && num_ack_blocks_written < num_ack_blocks; | 
 |          previous_start = itr->min(), ++itr) { | 
 |       const auto& interval = *itr; | 
 |       const uint64_t total_gap = previous_start - interval.max(); | 
 |       const size_t num_encoded_gaps = | 
 |           (total_gap + std::numeric_limits<uint8_t>::max() - 1) / | 
 |           std::numeric_limits<uint8_t>::max(); | 
 |  | 
 |       // Append empty ACK blocks because the gap is longer than a single gap. | 
 |       for (size_t i = 1; | 
 |            i < num_encoded_gaps && num_ack_blocks_written < num_ack_blocks; | 
 |            ++i) { | 
 |         if (!AppendAckBlock(std::numeric_limits<uint8_t>::max(), | 
 |                             ack_block_length, 0, writer)) { | 
 |           return false; | 
 |         } | 
 |         ++num_ack_blocks_written; | 
 |       } | 
 |       if (num_ack_blocks_written >= num_ack_blocks) { | 
 |         if (QUIC_PREDICT_FALSE(num_ack_blocks_written != num_ack_blocks)) { | 
 |           QUIC_BUG << "Wrote " << num_ack_blocks_written | 
 |                    << ", expected to write " << num_ack_blocks; | 
 |         } | 
 |         break; | 
 |       } | 
 |  | 
 |       const uint8_t last_gap = | 
 |           total_gap - | 
 |           (num_encoded_gaps - 1) * std::numeric_limits<uint8_t>::max(); | 
 |       // Append the final ACK block with a non-empty size. | 
 |       if (!AppendAckBlock(last_gap, ack_block_length, interval.Length(), | 
 |                           writer)) { | 
 |         return false; | 
 |       } | 
 |       ++num_ack_blocks_written; | 
 |     } | 
 |     DCHECK_EQ(num_ack_blocks, num_ack_blocks_written); | 
 |   } | 
 |   // Timestamps. | 
 |   // If we don't process timestamps or if we don't have enough available space | 
 |   // to append all the timestamps, don't append any of them. | 
 |   if (process_timestamps_ && writer->capacity() - writer->length() >= | 
 |                                  GetAckFrameTimeStampSize(frame)) { | 
 |     if (!AppendTimestampsToAckFrame(frame, writer)) { | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     uint8_t num_received_packets = 0; | 
 |     if (!writer->WriteBytes(&num_received_packets, 1)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendTimestampsToAckFrame(const QuicAckFrame& frame, | 
 |                                             QuicDataWriter* writer) { | 
 |   DCHECK_GE(std::numeric_limits<uint8_t>::max(), | 
 |             frame.received_packet_times.size()); | 
 |   // num_received_packets is only 1 byte. | 
 |   if (frame.received_packet_times.size() > | 
 |       std::numeric_limits<uint8_t>::max()) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint8_t num_received_packets = frame.received_packet_times.size(); | 
 |   if (!writer->WriteBytes(&num_received_packets, 1)) { | 
 |     return false; | 
 |   } | 
 |   if (num_received_packets == 0) { | 
 |     return true; | 
 |   } | 
 |  | 
 |   auto it = frame.received_packet_times.begin(); | 
 |   QuicPacketNumber packet_number = it->first; | 
 |   uint64_t delta_from_largest_observed = LargestAcked(frame) - packet_number; | 
 |  | 
 |   DCHECK_GE(std::numeric_limits<uint8_t>::max(), delta_from_largest_observed); | 
 |   if (delta_from_largest_observed > std::numeric_limits<uint8_t>::max()) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!writer->WriteUInt8(delta_from_largest_observed)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Use the lowest 4 bytes of the time delta from the creation_time_. | 
 |   const uint64_t time_epoch_delta_us = UINT64_C(1) << 32; | 
 |   uint32_t time_delta_us = | 
 |       static_cast<uint32_t>((it->second - creation_time_).ToMicroseconds() & | 
 |                             (time_epoch_delta_us - 1)); | 
 |   if (!writer->WriteUInt32(time_delta_us)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicTime prev_time = it->second; | 
 |  | 
 |   for (++it; it != frame.received_packet_times.end(); ++it) { | 
 |     packet_number = it->first; | 
 |     delta_from_largest_observed = LargestAcked(frame) - packet_number; | 
 |  | 
 |     if (delta_from_largest_observed > std::numeric_limits<uint8_t>::max()) { | 
 |       return false; | 
 |     } | 
 |  | 
 |     if (!writer->WriteUInt8(delta_from_largest_observed)) { | 
 |       return false; | 
 |     } | 
 |  | 
 |     uint64_t frame_time_delta_us = (it->second - prev_time).ToMicroseconds(); | 
 |     prev_time = it->second; | 
 |     if (!writer->WriteUFloat16(frame_time_delta_us)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendStopWaitingFrame(const QuicPacketHeader& header, | 
 |                                         const QuicStopWaitingFrame& frame, | 
 |                                         QuicDataWriter* writer) { | 
 |   DCHECK(!VersionHasIetfInvariantHeader(version_.transport_version)); | 
 |   DCHECK(frame.least_unacked.IsInitialized()); | 
 |   DCHECK_GE(header.packet_number, frame.least_unacked); | 
 |   const uint64_t least_unacked_delta = | 
 |       header.packet_number - frame.least_unacked; | 
 |   const uint64_t length_shift = header.packet_number_length * 8; | 
 |  | 
 |   if (least_unacked_delta >> length_shift > 0) { | 
 |     QUIC_BUG << "packet_number_length " << header.packet_number_length | 
 |              << " is too small for least_unacked_delta: " << least_unacked_delta | 
 |              << " packet_number:" << header.packet_number | 
 |              << " least_unacked:" << frame.least_unacked | 
 |              << " version:" << version_.transport_version; | 
 |     return false; | 
 |   } | 
 |   if (least_unacked_delta == 0) { | 
 |     return writer->WriteBytesToUInt64(header.packet_number_length, | 
 |                                       least_unacked_delta); | 
 |   } | 
 |   if (!AppendPacketNumber(header.packet_number_length, | 
 |                           QuicPacketNumber(least_unacked_delta), writer)) { | 
 |     QUIC_BUG << " seq failed: " << header.packet_number_length; | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendIetfAckFrameAndTypeByte(const QuicAckFrame& frame, | 
 |                                                QuicDataWriter* writer) { | 
 |   uint8_t type = IETF_ACK; | 
 |   uint64_t ecn_size = 0; | 
 |   if (frame.ecn_counters_populated && | 
 |       (frame.ect_0_count || frame.ect_1_count || frame.ecn_ce_count)) { | 
 |     // Change frame type to ACK_ECN if any ECN count is available. | 
 |     type = IETF_ACK_ECN; | 
 |     ecn_size = (QuicDataWriter::GetVarInt62Len(frame.ect_0_count) + | 
 |                 QuicDataWriter::GetVarInt62Len(frame.ect_1_count) + | 
 |                 QuicDataWriter::GetVarInt62Len(frame.ecn_ce_count)); | 
 |   } | 
 |  | 
 |   if (!writer->WriteUInt8(type)) { | 
 |     set_detailed_error("No room for frame-type"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicPacketNumber largest_acked = LargestAcked(frame); | 
 |   if (!writer->WriteVarInt62(largest_acked.ToUint64())) { | 
 |     set_detailed_error("No room for largest-acked in ack frame"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint64_t ack_delay_time_us = kVarInt62MaxValue; | 
 |   if (!frame.ack_delay_time.IsInfinite()) { | 
 |     DCHECK_LE(0u, frame.ack_delay_time.ToMicroseconds()); | 
 |     ack_delay_time_us = frame.ack_delay_time.ToMicroseconds(); | 
 |     ack_delay_time_us = ack_delay_time_us >> local_ack_delay_exponent_; | 
 |   } | 
 |  | 
 |   if (!writer->WriteVarInt62(ack_delay_time_us)) { | 
 |     set_detailed_error("No room for ack-delay in ack frame"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (frame.packets.Empty() || frame.packets.Max() != largest_acked) { | 
 |     QUIC_BUG << "Malformed ack frame: " << frame; | 
 |     set_detailed_error("Malformed ack frame"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Latch ack_block_count for potential truncation. | 
 |   const uint64_t ack_block_count = frame.packets.NumIntervals() - 1; | 
 |   QuicDataWriter count_writer(QuicDataWriter::GetVarInt62Len(ack_block_count), | 
 |                               writer->data() + writer->length()); | 
 |   if (!writer->WriteVarInt62(ack_block_count)) { | 
 |     set_detailed_error("No room for ack block count in ack frame"); | 
 |     return false; | 
 |   } | 
 |   auto iter = frame.packets.rbegin(); | 
 |   if (!writer->WriteVarInt62(iter->Length() - 1)) { | 
 |     set_detailed_error("No room for first ack block in ack frame"); | 
 |     return false; | 
 |   } | 
 |   QuicPacketNumber previous_smallest = iter->min(); | 
 |   ++iter; | 
 |   // Append remaining ACK blocks. | 
 |   uint64_t appended_ack_blocks = 0; | 
 |   for (; iter != frame.packets.rend(); ++iter) { | 
 |     const uint64_t gap = previous_smallest - iter->max() - 1; | 
 |     const uint64_t ack_range = iter->Length() - 1; | 
 |  | 
 |     if (writer->remaining() < ecn_size || | 
 |         writer->remaining() - ecn_size < | 
 |             QuicDataWriter::GetVarInt62Len(gap) + | 
 |                 QuicDataWriter::GetVarInt62Len(ack_range)) { | 
 |       // ACK range does not fit, truncate it. | 
 |       break; | 
 |     } | 
 |     const bool success = | 
 |         writer->WriteVarInt62(gap) && writer->WriteVarInt62(ack_range); | 
 |     DCHECK(success); | 
 |     previous_smallest = iter->min(); | 
 |     ++appended_ack_blocks; | 
 |   } | 
 |  | 
 |   if (appended_ack_blocks < ack_block_count) { | 
 |     // Truncation is needed, rewrite the ack block count. | 
 |     if (QuicDataWriter::GetVarInt62Len(appended_ack_blocks) != | 
 |             QuicDataWriter::GetVarInt62Len(ack_block_count) || | 
 |         !count_writer.WriteVarInt62(appended_ack_blocks)) { | 
 |       // This should never happen as ack_block_count is limited by | 
 |       // max_ack_ranges_. | 
 |       QUIC_BUG << "Ack frame truncation fails. ack_block_count: " | 
 |                << ack_block_count | 
 |                << ", appended count: " << appended_ack_blocks; | 
 |       set_detailed_error("ACK frame truncation fails"); | 
 |       return false; | 
 |     } | 
 |     QUIC_DLOG(INFO) << ENDPOINT << "ACK ranges get truncated from " | 
 |                     << ack_block_count << " to " << appended_ack_blocks; | 
 |   } | 
 |  | 
 |   if (type == IETF_ACK_ECN) { | 
 |     // Encode the ECN counts. | 
 |     if (!writer->WriteVarInt62(frame.ect_0_count)) { | 
 |       set_detailed_error("No room for ect_0_count in ack frame"); | 
 |       return false; | 
 |     } | 
 |     if (!writer->WriteVarInt62(frame.ect_1_count)) { | 
 |       set_detailed_error("No room for ect_1_count in ack frame"); | 
 |       return false; | 
 |     } | 
 |     if (!writer->WriteVarInt62(frame.ecn_ce_count)) { | 
 |       set_detailed_error("No room for ecn_ce_count in ack frame"); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendRstStreamFrame(const QuicRstStreamFrame& frame, | 
 |                                       QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return AppendIetfResetStreamFrame(frame, writer); | 
 |   } | 
 |   if (!writer->WriteUInt32(frame.stream_id)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!writer->WriteUInt64(frame.byte_offset)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint32_t error_code = static_cast<uint32_t>(frame.error_code); | 
 |   if (!writer->WriteUInt32(error_code)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendConnectionCloseFrame( | 
 |     const QuicConnectionCloseFrame& frame, | 
 |     QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return AppendIetfConnectionCloseFrame(frame, writer); | 
 |   } | 
 |   uint32_t error_code = static_cast<uint32_t>(frame.wire_error_code); | 
 |   if (!writer->WriteUInt32(error_code)) { | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteStringPiece16(TruncateErrorString(frame.error_details))) { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendGoAwayFrame(const QuicGoAwayFrame& frame, | 
 |                                    QuicDataWriter* writer) { | 
 |   uint32_t error_code = static_cast<uint32_t>(frame.error_code); | 
 |   if (!writer->WriteUInt32(error_code)) { | 
 |     return false; | 
 |   } | 
 |   uint32_t stream_id = static_cast<uint32_t>(frame.last_good_stream_id); | 
 |   if (!writer->WriteUInt32(stream_id)) { | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteStringPiece16(TruncateErrorString(frame.reason_phrase))) { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendWindowUpdateFrame(const QuicWindowUpdateFrame& frame, | 
 |                                          QuicDataWriter* writer) { | 
 |   uint32_t stream_id = static_cast<uint32_t>(frame.stream_id); | 
 |   if (!writer->WriteUInt32(stream_id)) { | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteUInt64(frame.max_data)) { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendBlockedFrame(const QuicBlockedFrame& frame, | 
 |                                     QuicDataWriter* writer) { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     if (frame.stream_id == QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |       return AppendDataBlockedFrame(frame, writer); | 
 |     } | 
 |     return AppendStreamDataBlockedFrame(frame, writer); | 
 |   } | 
 |   uint32_t stream_id = static_cast<uint32_t>(frame.stream_id); | 
 |   if (!writer->WriteUInt32(stream_id)) { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendPaddingFrame(const QuicPaddingFrame& frame, | 
 |                                     QuicDataWriter* writer) { | 
 |   if (frame.num_padding_bytes == 0) { | 
 |     return false; | 
 |   } | 
 |   if (frame.num_padding_bytes < 0) { | 
 |     QUIC_BUG_IF(frame.num_padding_bytes != -1); | 
 |     writer->WritePadding(); | 
 |     return true; | 
 |   } | 
 |   // Please note, num_padding_bytes includes type byte which has been written. | 
 |   return writer->WritePaddingBytes(frame.num_padding_bytes - 1); | 
 | } | 
 |  | 
 | bool QuicFramer::AppendMessageFrameAndTypeByte(const QuicMessageFrame& frame, | 
 |                                                bool last_frame_in_packet, | 
 |                                                QuicDataWriter* writer) { | 
 |   uint8_t type_byte; | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     type_byte = last_frame_in_packet ? IETF_EXTENSION_MESSAGE_NO_LENGTH_V99 | 
 |                                      : IETF_EXTENSION_MESSAGE_V99; | 
 |   } else { | 
 |     type_byte = last_frame_in_packet ? IETF_EXTENSION_MESSAGE_NO_LENGTH | 
 |                                      : IETF_EXTENSION_MESSAGE; | 
 |   } | 
 |   if (!writer->WriteUInt8(type_byte)) { | 
 |     return false; | 
 |   } | 
 |   if (!last_frame_in_packet && !writer->WriteVarInt62(frame.message_length)) { | 
 |     return false; | 
 |   } | 
 |   for (const auto& slice : frame.message_data) { | 
 |     if (!writer->WriteBytes(slice.data(), slice.length())) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::RaiseError(QuicErrorCode error) { | 
 |   QUIC_DLOG(INFO) << ENDPOINT << "Error: " << QuicErrorCodeToString(error) | 
 |                   << " detail: " << detailed_error_; | 
 |   set_error(error); | 
 |   if (visitor_) { | 
 |     visitor_->OnError(this); | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool QuicFramer::IsVersionNegotiation( | 
 |     const QuicPacketHeader& header, | 
 |     bool packet_has_ietf_packet_header) const { | 
 |   if (!packet_has_ietf_packet_header && | 
 |       perspective_ == Perspective::IS_CLIENT) { | 
 |     return header.version_flag; | 
 |   } | 
 |   if (header.form == IETF_QUIC_SHORT_HEADER_PACKET) { | 
 |     return false; | 
 |   } | 
 |   return header.long_packet_type == VERSION_NEGOTIATION; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendIetfConnectionCloseFrame( | 
 |     const QuicConnectionCloseFrame& frame, | 
 |     QuicDataWriter* writer) { | 
 |   if (frame.close_type != IETF_QUIC_TRANSPORT_CONNECTION_CLOSE && | 
 |       frame.close_type != IETF_QUIC_APPLICATION_CONNECTION_CLOSE) { | 
 |     QUIC_BUG << "Invalid close_type for writing IETF CONNECTION CLOSE."; | 
 |     set_detailed_error("Invalid close_type for writing IETF CONNECTION CLOSE."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!writer->WriteVarInt62(frame.wire_error_code)) { | 
 |     set_detailed_error("Can not write connection close frame error code"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (frame.close_type == IETF_QUIC_TRANSPORT_CONNECTION_CLOSE) { | 
 |     // Write the frame-type of the frame causing the error only | 
 |     // if it's a CONNECTION_CLOSE/Transport. | 
 |     if (!writer->WriteVarInt62(frame.transport_close_frame_type)) { | 
 |       set_detailed_error("Writing frame type failed."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   // There may be additional error information available in the extracted error | 
 |   // code. Encode the error information in the reason phrase and serialize the | 
 |   // result. | 
 |   std::string final_error_string = | 
 |       GenerateErrorString(frame.error_details, frame.quic_error_code); | 
 |   if (!writer->WriteStringPieceVarInt62( | 
 |           TruncateErrorString(final_error_string))) { | 
 |     set_detailed_error("Can not write connection close phrase"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfConnectionCloseFrame( | 
 |     QuicDataReader* reader, | 
 |     QuicConnectionCloseType type, | 
 |     QuicConnectionCloseFrame* frame) { | 
 |   frame->close_type = type; | 
 |  | 
 |   uint64_t error_code; | 
 |   if (!reader->ReadVarInt62(&error_code)) { | 
 |     set_detailed_error("Unable to read connection close error code."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   frame->wire_error_code = error_code; | 
 |  | 
 |   if (type == IETF_QUIC_TRANSPORT_CONNECTION_CLOSE) { | 
 |     // The frame-type of the frame causing the error is present only | 
 |     // if it's a CONNECTION_CLOSE/Transport. | 
 |     if (!reader->ReadVarInt62(&frame->transport_close_frame_type)) { | 
 |       set_detailed_error("Unable to read connection close frame type."); | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   uint64_t phrase_length; | 
 |   if (!reader->ReadVarInt62(&phrase_length)) { | 
 |     set_detailed_error("Unable to read connection close error details."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   quiche::QuicheStringPiece phrase; | 
 |   if (!reader->ReadStringPiece(&phrase, static_cast<size_t>(phrase_length))) { | 
 |     set_detailed_error("Unable to read connection close error details."); | 
 |     return false; | 
 |   } | 
 |   frame->error_details = std::string(phrase); | 
 |  | 
 |   // The frame may have an extracted error code in it. Look for it and | 
 |   // extract it. If it's not present, MaybeExtract will return | 
 |   // QUIC_IETF_GQUIC_ERROR_MISSING. | 
 |   MaybeExtractQuicErrorCode(frame); | 
 |   return true; | 
 | } | 
 |  | 
 | // IETF Quic Path Challenge/Response frames. | 
 | bool QuicFramer::ProcessPathChallengeFrame(QuicDataReader* reader, | 
 |                                            QuicPathChallengeFrame* frame) { | 
 |   if (!reader->ReadBytes(frame->data_buffer.data(), | 
 |                          frame->data_buffer.size())) { | 
 |     set_detailed_error("Can not read path challenge data."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessPathResponseFrame(QuicDataReader* reader, | 
 |                                           QuicPathResponseFrame* frame) { | 
 |   if (!reader->ReadBytes(frame->data_buffer.data(), | 
 |                          frame->data_buffer.size())) { | 
 |     set_detailed_error("Can not read path response data."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendPathChallengeFrame(const QuicPathChallengeFrame& frame, | 
 |                                           QuicDataWriter* writer) { | 
 |   if (!writer->WriteBytes(frame.data_buffer.data(), frame.data_buffer.size())) { | 
 |     set_detailed_error("Writing Path Challenge data failed."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendPathResponseFrame(const QuicPathResponseFrame& frame, | 
 |                                          QuicDataWriter* writer) { | 
 |   if (!writer->WriteBytes(frame.data_buffer.data(), frame.data_buffer.size())) { | 
 |     set_detailed_error("Writing Path Response data failed."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | // Add a new ietf-format stream reset frame. | 
 | // General format is | 
 | //    stream id | 
 | //    application error code | 
 | //    final offset | 
 | bool QuicFramer::AppendIetfResetStreamFrame(const QuicRstStreamFrame& frame, | 
 |                                             QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.stream_id))) { | 
 |     set_detailed_error("Writing reset-stream stream id failed."); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.ietf_error_code))) { | 
 |     set_detailed_error("Writing reset-stream error code failed."); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(static_cast<uint64_t>(frame.byte_offset))) { | 
 |     set_detailed_error("Writing reset-stream final-offset failed."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessIetfResetStreamFrame(QuicDataReader* reader, | 
 |                                              QuicRstStreamFrame* frame) { | 
 |   // Get Stream ID from frame. ReadVarIntStreamID returns false | 
 |   // if either A) there is a read error or B) the resulting value of | 
 |   // the Stream ID is larger than the maximum allowed value. | 
 |   if (!ReadUint32FromVarint62(reader, IETF_RST_STREAM, &frame->stream_id)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadVarInt62(&frame->ietf_error_code)) { | 
 |     set_detailed_error("Unable to read rst stream error code."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   frame->error_code = | 
 |       IetfResetStreamErrorCodeToRstStreamErrorCode(frame->ietf_error_code); | 
 |  | 
 |   if (!reader->ReadVarInt62(&frame->byte_offset)) { | 
 |     set_detailed_error("Unable to read rst stream sent byte offset."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessStopSendingFrame( | 
 |     QuicDataReader* reader, | 
 |     QuicStopSendingFrame* stop_sending_frame) { | 
 |   if (!ReadUint32FromVarint62(reader, IETF_STOP_SENDING, | 
 |                               &stop_sending_frame->stream_id)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   uint64_t error_code; | 
 |   if (!reader->ReadVarInt62(&error_code)) { | 
 |     set_detailed_error("Unable to read stop sending application error code."); | 
 |     return false; | 
 |   } | 
 |   // TODO(fkastenholz): when error codes go to uint64_t, remove this. | 
 |   if (error_code > 0xffff) { | 
 |     stop_sending_frame->application_error_code = 0xffff; | 
 |     QUIC_DLOG(ERROR) << "Stop sending error code (" << error_code | 
 |                      << ") > 0xffff"; | 
 |   } else { | 
 |     stop_sending_frame->application_error_code = | 
 |         static_cast<uint16_t>(error_code); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendStopSendingFrame( | 
 |     const QuicStopSendingFrame& stop_sending_frame, | 
 |     QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(stop_sending_frame.stream_id)) { | 
 |     set_detailed_error("Can not write stop sending stream id"); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62( | 
 |           static_cast<uint64_t>(stop_sending_frame.application_error_code))) { | 
 |     set_detailed_error("Can not write application error code"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | // Append/process IETF-Format MAX_DATA Frame | 
 | bool QuicFramer::AppendMaxDataFrame(const QuicWindowUpdateFrame& frame, | 
 |                                     QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.max_data)) { | 
 |     set_detailed_error("Can not write MAX_DATA byte-offset"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessMaxDataFrame(QuicDataReader* reader, | 
 |                                      QuicWindowUpdateFrame* frame) { | 
 |   frame->stream_id = QuicUtils::GetInvalidStreamId(transport_version()); | 
 |   if (!reader->ReadVarInt62(&frame->max_data)) { | 
 |     set_detailed_error("Can not read MAX_DATA byte-offset"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | // Append/process IETF-Format MAX_STREAM_DATA Frame | 
 | bool QuicFramer::AppendMaxStreamDataFrame(const QuicWindowUpdateFrame& frame, | 
 |                                           QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.stream_id)) { | 
 |     set_detailed_error("Can not write MAX_STREAM_DATA stream id"); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(frame.max_data)) { | 
 |     set_detailed_error("Can not write MAX_STREAM_DATA byte-offset"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessMaxStreamDataFrame(QuicDataReader* reader, | 
 |                                            QuicWindowUpdateFrame* frame) { | 
 |   if (!ReadUint32FromVarint62(reader, IETF_MAX_STREAM_DATA, | 
 |                               &frame->stream_id)) { | 
 |     return false; | 
 |   } | 
 |   if (!reader->ReadVarInt62(&frame->max_data)) { | 
 |     set_detailed_error("Can not read MAX_STREAM_DATA byte-count"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendMaxStreamsFrame(const QuicMaxStreamsFrame& frame, | 
 |                                        QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.stream_count)) { | 
 |     set_detailed_error("Can not write MAX_STREAMS stream count"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessMaxStreamsFrame(QuicDataReader* reader, | 
 |                                         QuicMaxStreamsFrame* frame, | 
 |                                         uint64_t frame_type) { | 
 |   if (!ReadUint32FromVarint62(reader, | 
 |                               static_cast<QuicIetfFrameType>(frame_type), | 
 |                               &frame->stream_count)) { | 
 |     return false; | 
 |   } | 
 |   frame->unidirectional = (frame_type == IETF_MAX_STREAMS_UNIDIRECTIONAL); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendDataBlockedFrame(const QuicBlockedFrame& frame, | 
 |                                         QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.offset)) { | 
 |     set_detailed_error("Can not write blocked offset."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessDataBlockedFrame(QuicDataReader* reader, | 
 |                                          QuicBlockedFrame* frame) { | 
 |   // Indicates that it is a BLOCKED frame (as opposed to STREAM_BLOCKED). | 
 |   frame->stream_id = QuicUtils::GetInvalidStreamId(transport_version()); | 
 |   if (!reader->ReadVarInt62(&frame->offset)) { | 
 |     set_detailed_error("Can not read blocked offset."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendStreamDataBlockedFrame(const QuicBlockedFrame& frame, | 
 |                                               QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.stream_id)) { | 
 |     set_detailed_error("Can not write stream blocked stream id."); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(frame.offset)) { | 
 |     set_detailed_error("Can not write stream blocked offset."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessStreamDataBlockedFrame(QuicDataReader* reader, | 
 |                                                QuicBlockedFrame* frame) { | 
 |   if (!ReadUint32FromVarint62(reader, IETF_STREAM_DATA_BLOCKED, | 
 |                               &frame->stream_id)) { | 
 |     return false; | 
 |   } | 
 |   if (!reader->ReadVarInt62(&frame->offset)) { | 
 |     set_detailed_error("Can not read stream blocked offset."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendStreamsBlockedFrame(const QuicStreamsBlockedFrame& frame, | 
 |                                            QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.stream_count)) { | 
 |     set_detailed_error("Can not write STREAMS_BLOCKED stream count"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessStreamsBlockedFrame(QuicDataReader* reader, | 
 |                                             QuicStreamsBlockedFrame* frame, | 
 |                                             uint64_t frame_type) { | 
 |   if (!ReadUint32FromVarint62(reader, | 
 |                               static_cast<QuicIetfFrameType>(frame_type), | 
 |                               &frame->stream_count)) { | 
 |     return false; | 
 |   } | 
 |   if (frame->stream_count > QuicUtils::GetMaxStreamCount()) { | 
 |     // If stream count is such that the resulting stream ID would exceed our | 
 |     // implementation limit, generate an error. | 
 |     set_detailed_error( | 
 |         "STREAMS_BLOCKED stream count exceeds implementation limit."); | 
 |     return false; | 
 |   } | 
 |   frame->unidirectional = (frame_type == IETF_STREAMS_BLOCKED_UNIDIRECTIONAL); | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendNewConnectionIdFrame( | 
 |     const QuicNewConnectionIdFrame& frame, | 
 |     QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.sequence_number)) { | 
 |     set_detailed_error("Can not write New Connection ID sequence number"); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteVarInt62(frame.retire_prior_to)) { | 
 |     set_detailed_error("Can not write New Connection ID retire_prior_to"); | 
 |     return false; | 
 |   } | 
 |   if (!writer->WriteLengthPrefixedConnectionId(frame.connection_id)) { | 
 |     set_detailed_error("Can not write New Connection ID frame connection ID"); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!writer->WriteBytes( | 
 |           static_cast<const void*>(&frame.stateless_reset_token), | 
 |           sizeof(frame.stateless_reset_token))) { | 
 |     set_detailed_error("Can not write New Connection ID Reset Token"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessNewConnectionIdFrame(QuicDataReader* reader, | 
 |                                              QuicNewConnectionIdFrame* frame) { | 
 |   if (!reader->ReadVarInt62(&frame->sequence_number)) { | 
 |     set_detailed_error( | 
 |         "Unable to read new connection ID frame sequence number."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadVarInt62(&frame->retire_prior_to)) { | 
 |     set_detailed_error( | 
 |         "Unable to read new connection ID frame retire_prior_to."); | 
 |     return false; | 
 |   } | 
 |   if (frame->retire_prior_to > frame->sequence_number) { | 
 |     set_detailed_error("Retire_prior_to > sequence_number."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadLengthPrefixedConnectionId(&frame->connection_id)) { | 
 |     set_detailed_error("Unable to read new connection ID frame connection id."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!QuicUtils::IsConnectionIdValidForVersion(frame->connection_id, | 
 |                                                 transport_version())) { | 
 |     set_detailed_error("Invalid new connection ID length for version."); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (!reader->ReadBytes(&frame->stateless_reset_token, | 
 |                          sizeof(frame->stateless_reset_token))) { | 
 |     set_detailed_error("Can not read new connection ID frame reset token."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::AppendRetireConnectionIdFrame( | 
 |     const QuicRetireConnectionIdFrame& frame, | 
 |     QuicDataWriter* writer) { | 
 |   if (!writer->WriteVarInt62(frame.sequence_number)) { | 
 |     set_detailed_error("Can not write Retire Connection ID sequence number"); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ProcessRetireConnectionIdFrame( | 
 |     QuicDataReader* reader, | 
 |     QuicRetireConnectionIdFrame* frame) { | 
 |   if (!reader->ReadVarInt62(&frame->sequence_number)) { | 
 |     set_detailed_error( | 
 |         "Unable to read retire connection ID frame sequence number."); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicFramer::ReadUint32FromVarint62(QuicDataReader* reader, | 
 |                                         QuicIetfFrameType type, | 
 |                                         QuicStreamId* id) { | 
 |   uint64_t temp_uint64; | 
 |   if (!reader->ReadVarInt62(&temp_uint64)) { | 
 |     set_detailed_error("Unable to read " + QuicIetfFrameTypeString(type) + | 
 |                        " frame stream id/count."); | 
 |     return false; | 
 |   } | 
 |   if (temp_uint64 > kMaxQuicStreamId) { | 
 |     set_detailed_error("Stream id/count of " + QuicIetfFrameTypeString(type) + | 
 |                        "frame is too large."); | 
 |     return false; | 
 |   } | 
 |   *id = static_cast<uint32_t>(temp_uint64); | 
 |   return true; | 
 | } | 
 |  | 
 | uint8_t QuicFramer::GetStreamFrameTypeByte(const QuicStreamFrame& frame, | 
 |                                            bool last_frame_in_packet) const { | 
 |   if (VersionHasIetfQuicFrames(version_.transport_version)) { | 
 |     return GetIetfStreamFrameTypeByte(frame, last_frame_in_packet); | 
 |   } | 
 |   uint8_t type_byte = 0; | 
 |   // Fin bit. | 
 |   type_byte |= frame.fin ? kQuicStreamFinMask : 0; | 
 |  | 
 |   // Data Length bit. | 
 |   type_byte <<= kQuicStreamDataLengthShift; | 
 |   type_byte |= last_frame_in_packet ? 0 : kQuicStreamDataLengthMask; | 
 |  | 
 |   // Offset 3 bits. | 
 |   type_byte <<= kQuicStreamShift; | 
 |   const size_t offset_len = GetStreamOffsetSize(frame.offset); | 
 |   if (offset_len > 0) { | 
 |     type_byte |= offset_len - 1; | 
 |   } | 
 |  | 
 |   // stream id 2 bits. | 
 |   type_byte <<= kQuicStreamIdShift; | 
 |   type_byte |= GetStreamIdSize(frame.stream_id) - 1; | 
 |   type_byte |= kQuicFrameTypeStreamMask;  // Set Stream Frame Type to 1. | 
 |  | 
 |   return type_byte; | 
 | } | 
 |  | 
 | uint8_t QuicFramer::GetIetfStreamFrameTypeByte( | 
 |     const QuicStreamFrame& frame, | 
 |     bool last_frame_in_packet) const { | 
 |   DCHECK(VersionHasIetfQuicFrames(version_.transport_version)); | 
 |   uint8_t type_byte = IETF_STREAM; | 
 |   if (!last_frame_in_packet) { | 
 |     type_byte |= IETF_STREAM_FRAME_LEN_BIT; | 
 |   } | 
 |   if (frame.offset != 0) { | 
 |     type_byte |= IETF_STREAM_FRAME_OFF_BIT; | 
 |   } | 
 |   if (frame.fin) { | 
 |     type_byte |= IETF_STREAM_FRAME_FIN_BIT; | 
 |   } | 
 |   return type_byte; | 
 | } | 
 |  | 
 | void QuicFramer::InferPacketHeaderTypeFromVersion() { | 
 |   // This function should only be called when server connection negotiates the | 
 |   // version. | 
 |   DCHECK_EQ(perspective_, Perspective::IS_SERVER); | 
 |   DCHECK(!infer_packet_header_type_from_version_); | 
 |   infer_packet_header_type_from_version_ = true; | 
 | } | 
 |  | 
 | void QuicFramer::EnableMultiplePacketNumberSpacesSupport() { | 
 |   if (supports_multiple_packet_number_spaces_) { | 
 |     QUIC_BUG << "Multiple packet number spaces has already been enabled"; | 
 |     return; | 
 |   } | 
 |   if (largest_packet_number_.IsInitialized()) { | 
 |     QUIC_BUG << "Try to enable multiple packet number spaces support after any " | 
 |                 "packet has been received."; | 
 |     return; | 
 |   } | 
 |  | 
 |   supports_multiple_packet_number_spaces_ = true; | 
 | } | 
 |  | 
 | // static | 
 | QuicErrorCode QuicFramer::ParsePublicHeaderDispatcher( | 
 |     const QuicEncryptedPacket& packet, | 
 |     uint8_t expected_destination_connection_id_length, | 
 |     PacketHeaderFormat* format, | 
 |     QuicLongHeaderType* long_packet_type, | 
 |     bool* version_present, | 
 |     bool* has_length_prefix, | 
 |     QuicVersionLabel* version_label, | 
 |     ParsedQuicVersion* parsed_version, | 
 |     QuicConnectionId* destination_connection_id, | 
 |     QuicConnectionId* source_connection_id, | 
 |     bool* retry_token_present, | 
 |     quiche::QuicheStringPiece* retry_token, | 
 |     std::string* detailed_error) { | 
 |   QuicDataReader reader(packet.data(), packet.length()); | 
 |   if (reader.IsDoneReading()) { | 
 |     *detailed_error = "Unable to read first byte."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |   const uint8_t first_byte = reader.PeekByte(); | 
 |   const bool ietf_format = QuicUtils::IsIetfPacketHeader(first_byte); | 
 |   uint8_t unused_first_byte; | 
 |   QuicVariableLengthIntegerLength retry_token_length_length; | 
 |   QuicErrorCode error_code = ParsePublicHeader( | 
 |       &reader, expected_destination_connection_id_length, ietf_format, | 
 |       &unused_first_byte, format, version_present, has_length_prefix, | 
 |       version_label, parsed_version, destination_connection_id, | 
 |       source_connection_id, long_packet_type, &retry_token_length_length, | 
 |       retry_token, detailed_error); | 
 |   *retry_token_present = | 
 |       retry_token_length_length != VARIABLE_LENGTH_INTEGER_LENGTH_0; | 
 |   return error_code; | 
 | } | 
 |  | 
 | // static | 
 | QuicErrorCode QuicFramer::ParsePublicHeaderGoogleQuic( | 
 |     QuicDataReader* reader, | 
 |     uint8_t* first_byte, | 
 |     PacketHeaderFormat* format, | 
 |     bool* version_present, | 
 |     QuicVersionLabel* version_label, | 
 |     ParsedQuicVersion* parsed_version, | 
 |     QuicConnectionId* destination_connection_id, | 
 |     std::string* detailed_error) { | 
 |   *format = GOOGLE_QUIC_PACKET; | 
 |   *version_present = (*first_byte & PACKET_PUBLIC_FLAGS_VERSION) != 0; | 
 |   uint8_t destination_connection_id_length = 0; | 
 |   if ((*first_byte & PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID) != 0) { | 
 |     destination_connection_id_length = kQuicDefaultConnectionIdLength; | 
 |   } | 
 |   if (!reader->ReadConnectionId(destination_connection_id, | 
 |                                 destination_connection_id_length)) { | 
 |     *detailed_error = "Unable to read ConnectionId."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |   if (*version_present) { | 
 |     if (!ProcessVersionLabel(reader, version_label)) { | 
 |       *detailed_error = "Unable to read protocol version."; | 
 |       return QUIC_INVALID_PACKET_HEADER; | 
 |     } | 
 |     *parsed_version = ParseQuicVersionLabel(*version_label); | 
 |   } | 
 |   return QUIC_NO_ERROR; | 
 | } | 
 |  | 
 | namespace { | 
 |  | 
 | const QuicVersionLabel kProxVersionLabel = 0x50524F58;  // "PROX" | 
 |  | 
 | inline bool PacketHasLengthPrefixedConnectionIds( | 
 |     const QuicDataReader& reader, | 
 |     ParsedQuicVersion parsed_version, | 
 |     QuicVersionLabel version_label, | 
 |     uint8_t first_byte) { | 
 |   if (parsed_version.transport_version != QUIC_VERSION_UNSUPPORTED) { | 
 |     return parsed_version.HasLengthPrefixedConnectionIds(); | 
 |   } | 
 |  | 
 |   // Received unsupported version, check known old unsupported versions. | 
 |   if (QuicVersionLabelUses4BitConnectionIdLength(version_label)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Received unknown version, check connection ID length byte. | 
 |   if (reader.IsDoneReading()) { | 
 |     // This check is required to safely peek the connection ID length byte. | 
 |     return true; | 
 |   } | 
 |   const uint8_t connection_id_length_byte = reader.PeekByte(); | 
 |  | 
 |   // Check for packets produced by older versions of | 
 |   // QuicFramer::WriteClientVersionNegotiationProbePacket | 
 |   if (first_byte == 0xc0 && (connection_id_length_byte & 0x0f) == 0 && | 
 |       connection_id_length_byte >= 0x50 && version_label == 0xcabadaba) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Check for munged packets with version tag PROX. | 
 |   if ((connection_id_length_byte & 0x0f) == 0 && | 
 |       connection_id_length_byte >= 0x20 && version_label == kProxVersionLabel) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | inline bool ParseLongHeaderConnectionIds( | 
 |     QuicDataReader* reader, | 
 |     bool has_length_prefix, | 
 |     QuicVersionLabel version_label, | 
 |     QuicConnectionId* destination_connection_id, | 
 |     QuicConnectionId* source_connection_id, | 
 |     std::string* detailed_error) { | 
 |   if (has_length_prefix) { | 
 |     if (!reader->ReadLengthPrefixedConnectionId(destination_connection_id)) { | 
 |       *detailed_error = "Unable to read destination connection ID."; | 
 |       return false; | 
 |     } | 
 |     if (!reader->ReadLengthPrefixedConnectionId(source_connection_id)) { | 
 |       if (version_label == kProxVersionLabel) { | 
 |         // The "PROX" version does not follow the length-prefixed invariants, | 
 |         // and can therefore attempt to read a payload byte and interpret it | 
 |         // as the source connection ID length, which could fail to parse. | 
 |         // In that scenario we keep the source connection ID empty but mark | 
 |         // parsing as successful. | 
 |         return true; | 
 |       } | 
 |       *detailed_error = "Unable to read source connection ID."; | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     // Parse connection ID lengths. | 
 |     uint8_t connection_id_lengths_byte; | 
 |     if (!reader->ReadUInt8(&connection_id_lengths_byte)) { | 
 |       *detailed_error = "Unable to read connection ID lengths."; | 
 |       return false; | 
 |     } | 
 |     uint8_t destination_connection_id_length = | 
 |         (connection_id_lengths_byte & kDestinationConnectionIdLengthMask) >> 4; | 
 |     if (destination_connection_id_length != 0) { | 
 |       destination_connection_id_length += kConnectionIdLengthAdjustment; | 
 |     } | 
 |     uint8_t source_connection_id_length = | 
 |         connection_id_lengths_byte & kSourceConnectionIdLengthMask; | 
 |     if (source_connection_id_length != 0) { | 
 |       source_connection_id_length += kConnectionIdLengthAdjustment; | 
 |     } | 
 |  | 
 |     // Read destination connection ID. | 
 |     if (!reader->ReadConnectionId(destination_connection_id, | 
 |                                   destination_connection_id_length)) { | 
 |       *detailed_error = "Unable to read destination connection ID."; | 
 |       return false; | 
 |     } | 
 |  | 
 |     // Read source connection ID. | 
 |     if (!reader->ReadConnectionId(source_connection_id, | 
 |                                   source_connection_id_length)) { | 
 |       *detailed_error = "Unable to read source connection ID."; | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | // static | 
 | QuicErrorCode QuicFramer::ParsePublicHeader( | 
 |     QuicDataReader* reader, | 
 |     uint8_t expected_destination_connection_id_length, | 
 |     bool ietf_format, | 
 |     uint8_t* first_byte, | 
 |     PacketHeaderFormat* format, | 
 |     bool* version_present, | 
 |     bool* has_length_prefix, | 
 |     QuicVersionLabel* version_label, | 
 |     ParsedQuicVersion* parsed_version, | 
 |     QuicConnectionId* destination_connection_id, | 
 |     QuicConnectionId* source_connection_id, | 
 |     QuicLongHeaderType* long_packet_type, | 
 |     QuicVariableLengthIntegerLength* retry_token_length_length, | 
 |     quiche::QuicheStringPiece* retry_token, | 
 |     std::string* detailed_error) { | 
 |   *version_present = false; | 
 |   *has_length_prefix = false; | 
 |   *version_label = 0; | 
 |   *parsed_version = UnsupportedQuicVersion(); | 
 |   *source_connection_id = EmptyQuicConnectionId(); | 
 |   *long_packet_type = INVALID_PACKET_TYPE; | 
 |   *retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_0; | 
 |   *retry_token = quiche::QuicheStringPiece(); | 
 |   *detailed_error = ""; | 
 |  | 
 |   if (!reader->ReadUInt8(first_byte)) { | 
 |     *detailed_error = "Unable to read first byte."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   if (!ietf_format) { | 
 |     return ParsePublicHeaderGoogleQuic( | 
 |         reader, first_byte, format, version_present, version_label, | 
 |         parsed_version, destination_connection_id, detailed_error); | 
 |   } | 
 |  | 
 |   *format = GetIetfPacketHeaderFormat(*first_byte); | 
 |  | 
 |   if (*format == IETF_QUIC_SHORT_HEADER_PACKET) { | 
 |     // Read destination connection ID using | 
 |     // expected_destination_connection_id_length to determine its length. | 
 |     if (!reader->ReadConnectionId(destination_connection_id, | 
 |                                   expected_destination_connection_id_length)) { | 
 |       *detailed_error = "Unable to read destination connection ID."; | 
 |       return QUIC_INVALID_PACKET_HEADER; | 
 |     } | 
 |     return QUIC_NO_ERROR; | 
 |   } | 
 |  | 
 |   DCHECK_EQ(IETF_QUIC_LONG_HEADER_PACKET, *format); | 
 |   *version_present = true; | 
 |   if (!ProcessVersionLabel(reader, version_label)) { | 
 |     *detailed_error = "Unable to read protocol version."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   if (*version_label == 0) { | 
 |     *long_packet_type = VERSION_NEGOTIATION; | 
 |   } | 
 |  | 
 |   // Parse version. | 
 |   *parsed_version = ParseQuicVersionLabel(*version_label); | 
 |  | 
 |   // Figure out which IETF QUIC invariants this packet follows. | 
 |   *has_length_prefix = PacketHasLengthPrefixedConnectionIds( | 
 |       *reader, *parsed_version, *version_label, *first_byte); | 
 |  | 
 |   // Parse connection IDs. | 
 |   if (!ParseLongHeaderConnectionIds(reader, *has_length_prefix, *version_label, | 
 |                                     destination_connection_id, | 
 |                                     source_connection_id, detailed_error)) { | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   if (parsed_version->transport_version == QUIC_VERSION_UNSUPPORTED) { | 
 |     // Skip parsing of long packet type and retry token for unknown versions. | 
 |     return QUIC_NO_ERROR; | 
 |   } | 
 |  | 
 |   // Parse long packet type. | 
 |   if (!GetLongHeaderType(*first_byte, long_packet_type)) { | 
 |     *detailed_error = "Unable to parse long packet type."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   if (!parsed_version->SupportsRetry() || *long_packet_type != INITIAL) { | 
 |     // Retry token is only present on initial packets for some versions. | 
 |     return QUIC_NO_ERROR; | 
 |   } | 
 |  | 
 |   *retry_token_length_length = reader->PeekVarInt62Length(); | 
 |   uint64_t retry_token_length; | 
 |   if (!reader->ReadVarInt62(&retry_token_length)) { | 
 |     *retry_token_length_length = VARIABLE_LENGTH_INTEGER_LENGTH_0; | 
 |     *detailed_error = "Unable to read retry token length."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   if (!reader->ReadStringPiece(retry_token, retry_token_length)) { | 
 |     *detailed_error = "Unable to read retry token."; | 
 |     return QUIC_INVALID_PACKET_HEADER; | 
 |   } | 
 |  | 
 |   return QUIC_NO_ERROR; | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::WriteClientVersionNegotiationProbePacket( | 
 |     char* packet_bytes, | 
 |     QuicByteCount packet_length, | 
 |     const char* destination_connection_id_bytes, | 
 |     uint8_t destination_connection_id_length) { | 
 |   if (packet_bytes == nullptr) { | 
 |     QUIC_BUG << "Invalid packet_bytes"; | 
 |     return false; | 
 |   } | 
 |   if (packet_length < kMinPacketSizeForVersionNegotiation || | 
 |       packet_length > 65535) { | 
 |     QUIC_BUG << "Invalid packet_length"; | 
 |     return false; | 
 |   } | 
 |   if (destination_connection_id_length > kQuicMaxConnectionId4BitLength || | 
 |       destination_connection_id_length < | 
 |           kQuicMinimumInitialConnectionIdLength) { | 
 |     QUIC_BUG << "Invalid connection_id_length"; | 
 |     return false; | 
 |   } | 
 |   const bool use_length_prefix = | 
 |       GetQuicFlag(FLAGS_quic_prober_uses_length_prefixed_connection_ids); | 
 |   const uint8_t last_version_byte = use_length_prefix ? 0xda : 0xba; | 
 |   // clang-format off | 
 |   const unsigned char packet_start_bytes[] = { | 
 |     // IETF long header with fixed bit set, type initial, all-0 encrypted bits. | 
 |     0xc0, | 
 |     // Version, part of the IETF space reserved for negotiation. | 
 |     // This intentionally differs from QuicVersionReservedForNegotiation() | 
 |     // to allow differentiating them over the wire. | 
 |     0xca, 0xba, 0xda, last_version_byte, | 
 |   }; | 
 |   // clang-format on | 
 |   static_assert(sizeof(packet_start_bytes) == 5, "bad packet_start_bytes size"); | 
 |   QuicDataWriter writer(packet_length, packet_bytes); | 
 |   if (!writer.WriteBytes(packet_start_bytes, sizeof(packet_start_bytes))) { | 
 |     QUIC_BUG << "Failed to write packet start"; | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicConnectionId destination_connection_id(destination_connection_id_bytes, | 
 |                                              destination_connection_id_length); | 
 |   if (!AppendIetfConnectionIds( | 
 |           /*version_flag=*/true, use_length_prefix, destination_connection_id, | 
 |           EmptyQuicConnectionId(), &writer)) { | 
 |     QUIC_BUG << "Failed to write connection IDs"; | 
 |     return false; | 
 |   } | 
 |   // Add 8 bytes of zeroes followed by 8 bytes of ones to ensure that this does | 
 |   // not parse with any known version. The zeroes make sure that packet numbers, | 
 |   // retry token lengths and payload lengths are parsed as zero, and if the | 
 |   // zeroes are treated as padding frames, 0xff is known to not parse as a | 
 |   // valid frame type. | 
 |   if (!writer.WriteUInt64(0) || | 
 |       !writer.WriteUInt64(std::numeric_limits<uint64_t>::max())) { | 
 |     QUIC_BUG << "Failed to write 18 bytes"; | 
 |     return false; | 
 |   } | 
 |   // Make sure the polite greeting below is padded to a 16-byte boundary to | 
 |   // make it easier to read in tcpdump. | 
 |   while (writer.length() % 16 != 0) { | 
 |     if (!writer.WriteUInt8(0)) { | 
 |       QUIC_BUG << "Failed to write padding byte"; | 
 |       return false; | 
 |     } | 
 |   } | 
 |   // Add a polite greeting in case a human sees this in tcpdump. | 
 |   static const char polite_greeting[] = | 
 |       "This packet only exists to trigger IETF QUIC version negotiation. " | 
 |       "Please respond with a Version Negotiation packet indicating what " | 
 |       "versions you support. Thank you and have a nice day."; | 
 |   if (!writer.WriteBytes(polite_greeting, sizeof(polite_greeting))) { | 
 |     QUIC_BUG << "Failed to write polite greeting"; | 
 |     return false; | 
 |   } | 
 |   // Fill the rest of the packet with zeroes. | 
 |   writer.WritePadding(); | 
 |   DCHECK_EQ(0u, writer.remaining()); | 
 |   return true; | 
 | } | 
 |  | 
 | // static | 
 | bool QuicFramer::ParseServerVersionNegotiationProbeResponse( | 
 |     const char* packet_bytes, | 
 |     QuicByteCount packet_length, | 
 |     char* source_connection_id_bytes, | 
 |     uint8_t* source_connection_id_length_out, | 
 |     std::string* detailed_error) { | 
 |   if (detailed_error == nullptr) { | 
 |     QUIC_BUG << "Invalid error_details"; | 
 |     return false; | 
 |   } | 
 |   *detailed_error = ""; | 
 |   if (packet_bytes == nullptr) { | 
 |     *detailed_error = "Invalid packet_bytes"; | 
 |     return false; | 
 |   } | 
 |   if (packet_length < 6) { | 
 |     *detailed_error = "Invalid packet_length"; | 
 |     return false; | 
 |   } | 
 |   if (source_connection_id_bytes == nullptr) { | 
 |     *detailed_error = "Invalid source_connection_id_bytes"; | 
 |     return false; | 
 |   } | 
 |   if (source_connection_id_length_out == nullptr) { | 
 |     *detailed_error = "Invalid source_connection_id_length_out"; | 
 |     return false; | 
 |   } | 
 |   QuicDataReader reader(packet_bytes, packet_length); | 
 |   uint8_t type_byte = 0; | 
 |   if (!reader.ReadUInt8(&type_byte)) { | 
 |     *detailed_error = "Failed to read type byte"; | 
 |     return false; | 
 |   } | 
 |   if ((type_byte & 0x80) == 0) { | 
 |     *detailed_error = "Packet does not have long header"; | 
 |     return false; | 
 |   } | 
 |   uint32_t version = 0; | 
 |   if (!reader.ReadUInt32(&version)) { | 
 |     *detailed_error = "Failed to read version"; | 
 |     return false; | 
 |   } | 
 |   if (version != 0) { | 
 |     *detailed_error = "Packet is not a version negotiation packet"; | 
 |     return false; | 
 |   } | 
 |   const bool use_length_prefix = | 
 |       GetQuicFlag(FLAGS_quic_prober_uses_length_prefixed_connection_ids); | 
 |   QuicConnectionId destination_connection_id, source_connection_id; | 
 |   if (use_length_prefix) { | 
 |     if (!reader.ReadLengthPrefixedConnectionId(&destination_connection_id)) { | 
 |       *detailed_error = "Failed to read destination connection ID"; | 
 |       return false; | 
 |     } | 
 |     if (!reader.ReadLengthPrefixedConnectionId(&source_connection_id)) { | 
 |       *detailed_error = "Failed to read source connection ID"; | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     uint8_t expected_server_connection_id_length = 0, | 
 |             destination_connection_id_length = 0, | 
 |             source_connection_id_length = 0; | 
 |     if (!ProcessAndValidateIetfConnectionIdLength( | 
 |             &reader, UnsupportedQuicVersion(), Perspective::IS_CLIENT, | 
 |             /*should_update_expected_server_connection_id_length=*/true, | 
 |             &expected_server_connection_id_length, | 
 |             &destination_connection_id_length, &source_connection_id_length, | 
 |             detailed_error)) { | 
 |       return false; | 
 |     } | 
 |     if (!reader.ReadConnectionId(&destination_connection_id, | 
 |                                  destination_connection_id_length)) { | 
 |       *detailed_error = "Failed to read destination connection ID"; | 
 |       return false; | 
 |     } | 
 |     if (!reader.ReadConnectionId(&source_connection_id, | 
 |                                  source_connection_id_length)) { | 
 |       *detailed_error = "Failed to read source connection ID"; | 
 |       return false; | 
 |     } | 
 |   } | 
 |  | 
 |   if (destination_connection_id.length() != 0) { | 
 |     *detailed_error = "Received unexpected destination connection ID length"; | 
 |     return false; | 
 |   } | 
 |  | 
 |   memcpy(source_connection_id_bytes, source_connection_id.data(), | 
 |          source_connection_id.length()); | 
 |   *source_connection_id_length_out = source_connection_id.length(); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | // Look for and parse the error code from the "<quic_error_code>:" text that | 
 | // may be present at the start of the CONNECTION_CLOSE error details string. | 
 | // This text, inserted by the peer if it's using Google's QUIC implementation, | 
 | // contains additional error information that narrows down the exact error.  If | 
 | // the string is not found, or is not properly formed, it returns | 
 | // ErrorCode::QUIC_IETF_GQUIC_ERROR_MISSING | 
 | void MaybeExtractQuicErrorCode(QuicConnectionCloseFrame* frame) { | 
 |   std::vector<quiche::QuicheStringPiece> ed = | 
 |       quiche::QuicheTextUtils::Split(frame->error_details, ':'); | 
 |   uint64_t extracted_error_code; | 
 |   if (ed.size() < 2 || !quiche::QuicheTextUtils::IsAllDigits(ed[0]) || | 
 |       !quiche::QuicheTextUtils::StringToUint64(ed[0], &extracted_error_code)) { | 
 |     if (frame->close_type == IETF_QUIC_TRANSPORT_CONNECTION_CLOSE && | 
 |         frame->wire_error_code == NO_IETF_QUIC_ERROR) { | 
 |       frame->quic_error_code = QUIC_NO_ERROR; | 
 |     } else { | 
 |       frame->quic_error_code = QUIC_IETF_GQUIC_ERROR_MISSING; | 
 |     } | 
 |     return; | 
 |   } | 
 |   // Return the error code (numeric) and the error details string without the | 
 |   // error code prefix. Note that Split returns everything up to, but not | 
 |   // including, the split character, so the length of ed[0] is just the number | 
 |   // of digits in the error number. In removing the prefix, 1 is added to the | 
 |   // length to account for the : | 
 |   quiche::QuicheStringPiece x = quiche::QuicheStringPiece(frame->error_details); | 
 |   x.remove_prefix(ed[0].length() + 1); | 
 |   frame->error_details = std::string(x); | 
 |   frame->quic_error_code = static_cast<QuicErrorCode>(extracted_error_code); | 
 | } | 
 |  | 
 | #undef ENDPOINT  // undef for jumbo builds | 
 | }  // namespace quic |