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quiche / quiche.git / 5a5661f9da6fa251d421179cf77271dc4d116065 / . / quic / core / quic_packet_creator.cc
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// 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_packet_creator.h"
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <string>
#include <utility>
#include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h"
#include "net/third_party/quiche/src/quic/core/frames/quic_frame.h"
#include "net/third_party/quiche/src/quic/core/frames/quic_path_challenge_frame.h"
#include "net/third_party/quiche/src/quic/core/frames/quic_stream_frame.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_writer.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_arraysize.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.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_server_stats.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_string_piece.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_text_utils.h"
namespace quic {
namespace {
QuicLongHeaderType EncryptionlevelToLongHeaderType(EncryptionLevel level) {
switch (level) {
case ENCRYPTION_INITIAL:
return INITIAL;
case ENCRYPTION_HANDSHAKE:
return HANDSHAKE;
case ENCRYPTION_ZERO_RTT:
return ZERO_RTT_PROTECTED;
case ENCRYPTION_FORWARD_SECURE:
QUIC_BUG
<< "Try to derive long header type for packet with encryption level: "
<< EncryptionLevelToString(level);
return INVALID_PACKET_TYPE;
default:
QUIC_BUG << EncryptionLevelToString(level);
return INVALID_PACKET_TYPE;
}
}
// ScopedPacketContextSwitcher saves |packet|'s states and change states
// during its construction. When the switcher goes out of scope, it restores
// saved states.
class ScopedPacketContextSwitcher {
public:
ScopedPacketContextSwitcher(QuicPacketNumber packet_number,
QuicPacketNumberLength packet_number_length,
EncryptionLevel encryption_level,
SerializedPacket* packet)
: saved_packet_number_(packet->packet_number),
saved_packet_number_length_(packet->packet_number_length),
saved_encryption_level_(packet->encryption_level),
packet_(packet) {
packet_->packet_number = packet_number,
packet_->packet_number_length = packet_number_length;
packet_->encryption_level = encryption_level;
}
~ScopedPacketContextSwitcher() {
packet_->packet_number = saved_packet_number_;
packet_->packet_number_length = saved_packet_number_length_;
packet_->encryption_level = saved_encryption_level_;
}
private:
const QuicPacketNumber saved_packet_number_;
const QuicPacketNumberLength saved_packet_number_length_;
const EncryptionLevel saved_encryption_level_;
SerializedPacket* packet_;
};
} // namespace
#define ENDPOINT \
(framer_->perspective() == Perspective::IS_SERVER ? "Server: " : "Client: ")
QuicPacketCreator::QuicPacketCreator(QuicConnectionId server_connection_id,
QuicFramer* framer,
DelegateInterface* delegate)
: QuicPacketCreator(server_connection_id,
framer,
QuicRandom::GetInstance(),
delegate) {}
QuicPacketCreator::QuicPacketCreator(QuicConnectionId server_connection_id,
QuicFramer* framer,
QuicRandom* random,
DelegateInterface* delegate)
: delegate_(delegate),
debug_delegate_(nullptr),
framer_(framer),
random_(random),
send_version_in_packet_(framer->perspective() == Perspective::IS_CLIENT),
have_diversification_nonce_(false),
max_packet_length_(0),
server_connection_id_included_(CONNECTION_ID_PRESENT),
packet_size_(0),
server_connection_id_(server_connection_id),
client_connection_id_(EmptyQuicConnectionId()),
packet_(QuicPacketNumber(),
PACKET_1BYTE_PACKET_NUMBER,
nullptr,
0,
false,
false),
pending_padding_bytes_(0),
needs_full_padding_(false),
next_transmission_type_(NOT_RETRANSMISSION),
flusher_attached_(false),
fully_pad_crypto_handshake_packets_(true),
latched_hard_max_packet_length_(0),
combine_generator_and_creator_(
GetQuicReloadableFlag(quic_combine_generator_and_creator)),
populate_nonretransmittable_frames_(
GetQuicReloadableFlag(quic_populate_nonretransmittable_frames)) {
SetMaxPacketLength(kDefaultMaxPacketSize);
if (combine_generator_and_creator_) {
QUIC_RELOADABLE_FLAG_COUNT(quic_combine_generator_and_creator);
}
if (populate_nonretransmittable_frames_) {
QUIC_RELOADABLE_FLAG_COUNT(quic_populate_nonretransmittable_frames);
}
}
QuicPacketCreator::~QuicPacketCreator() {
DeleteFrames(&packet_.retransmittable_frames);
}
void QuicPacketCreator::SetEncrypter(EncryptionLevel level,
std::unique_ptr<QuicEncrypter> encrypter) {
framer_->SetEncrypter(level, std::move(encrypter));
max_plaintext_size_ = framer_->GetMaxPlaintextSize(max_packet_length_);
}
bool QuicPacketCreator::CanSetMaxPacketLength() const {
// |max_packet_length_| should not be changed mid-packet.
return queued_frames_.empty();
}
void QuicPacketCreator::SetMaxPacketLength(QuicByteCount length) {
DCHECK(CanSetMaxPacketLength());
// Avoid recomputing |max_plaintext_size_| if the length does not actually
// change.
if (length == max_packet_length_) {
return;
}
max_packet_length_ = length;
max_plaintext_size_ = framer_->GetMaxPlaintextSize(max_packet_length_);
QUIC_BUG_IF(max_plaintext_size_ - PacketHeaderSize() <
MinPlaintextPacketSize(framer_->version()))
<< "Attempted to set max packet length too small";
}
void QuicPacketCreator::SetSoftMaxPacketLength(QuicByteCount length) {
DCHECK(CanSetMaxPacketLength());
if (length > max_packet_length_) {
QUIC_BUG << ENDPOINT
<< "Try to increase max_packet_length_ in "
"SetSoftMaxPacketLength, use SetMaxPacketLength instead.";
return;
}
if (framer_->GetMaxPlaintextSize(length) <
PacketHeaderSize() + MinPlaintextPacketSize(framer_->version())) {
QUIC_DLOG(INFO) << length << " is too small to fit packet header";
return;
}
QUIC_DVLOG(1) << "Setting soft max packet length to: " << length;
latched_hard_max_packet_length_ = max_packet_length_;
max_packet_length_ = length;
max_plaintext_size_ = framer_->GetMaxPlaintextSize(length);
}
// Stops serializing version of the protocol in packets sent after this call.
// A packet that is already open might send kQuicVersionSize bytes less than the
// maximum packet size if we stop sending version before it is serialized.
void QuicPacketCreator::StopSendingVersion() {
DCHECK(send_version_in_packet_);
DCHECK(!VersionHasIetfInvariantHeader(framer_->transport_version()));
send_version_in_packet_ = false;
if (packet_size_ > 0) {
DCHECK_LT(kQuicVersionSize, packet_size_);
packet_size_ -= kQuicVersionSize;
}
}
void QuicPacketCreator::SetDiversificationNonce(
const DiversificationNonce& nonce) {
DCHECK(!have_diversification_nonce_);
have_diversification_nonce_ = true;
diversification_nonce_ = nonce;
}
void QuicPacketCreator::UpdatePacketNumberLength(
QuicPacketNumber least_packet_awaited_by_peer,
QuicPacketCount max_packets_in_flight) {
if (!queued_frames_.empty()) {
// Don't change creator state if there are frames queued.
QUIC_BUG << "Called UpdatePacketNumberLength with " << queued_frames_.size()
<< " queued_frames. First frame type:"
<< queued_frames_.front().type
<< " last frame type:" << queued_frames_.back().type;
return;
}
DCHECK_LE(least_packet_awaited_by_peer, packet_.packet_number + 1);
const uint64_t current_delta =
packet_.packet_number + 1 - least_packet_awaited_by_peer;
const uint64_t delta = std::max(current_delta, max_packets_in_flight);
packet_.packet_number_length = QuicFramer::GetMinPacketNumberLength(
framer_->transport_version(), QuicPacketNumber(delta * 4));
}
void QuicPacketCreator::SkipNPacketNumbers(
QuicPacketCount count,
QuicPacketNumber least_packet_awaited_by_peer,
QuicPacketCount max_packets_in_flight) {
if (!queued_frames_.empty()) {
// Don't change creator state if there are frames queued.
QUIC_BUG << "Called SkipNPacketNumbers with " << queued_frames_.size()
<< " queued_frames. First frame type:"
<< queued_frames_.front().type
<< " last frame type:" << queued_frames_.back().type;
return;
}
if (packet_.packet_number > packet_.packet_number + count) {
// Skipping count packet numbers causes packet number wrapping around,
// reject it.
QUIC_LOG(WARNING) << "Skipping " << count
<< " packet numbers causes packet number wrapping "
"around, least_packet_awaited_by_peer: "
<< least_packet_awaited_by_peer
<< " packet_number:" << packet_.packet_number;
return;
}
packet_.packet_number += count;
// Packet number changes, update packet number length if necessary.
UpdatePacketNumberLength(least_packet_awaited_by_peer, max_packets_in_flight);
}
bool QuicPacketCreator::ConsumeCryptoDataToFillCurrentPacket(
EncryptionLevel level,
size_t write_length,
QuicStreamOffset offset,
bool needs_full_padding,
TransmissionType transmission_type,
QuicFrame* frame) {
if (!CreateCryptoFrame(level, write_length, offset, frame)) {
return false;
}
// When crypto data was sent in stream frames, ConsumeData is called with
// |needs_full_padding = true|. Keep the same behavior here when sending
// crypto frames.
//
// TODO(nharper): Check what the IETF drafts say about padding out initial
// messages and change this as appropriate.
if (needs_full_padding) {
needs_full_padding_ = true;
}
return AddFrame(*frame, transmission_type);
}
bool QuicPacketCreator::ConsumeDataToFillCurrentPacket(
QuicStreamId id,
size_t data_size,
QuicStreamOffset offset,
bool fin,
bool needs_full_padding,
TransmissionType transmission_type,
QuicFrame* frame) {
if (!HasRoomForStreamFrame(id, offset, data_size)) {
return false;
}
CreateStreamFrame(id, data_size, offset, fin, frame);
// Explicitly disallow multi-packet CHLOs.
if (GetQuicFlag(FLAGS_quic_enforce_single_packet_chlo) &&
StreamFrameIsClientHello(frame->stream_frame) &&
frame->stream_frame.data_length < data_size) {
const std::string error_details =
"Client hello won't fit in a single packet.";
QUIC_BUG << error_details << " Constructed stream frame length: "
<< frame->stream_frame.data_length
<< " CHLO length: " << data_size;
delegate_->OnUnrecoverableError(QUIC_CRYPTO_CHLO_TOO_LARGE, error_details);
return false;
}
if (!AddFrame(*frame, transmission_type)) {
// Fails if we try to write unencrypted stream data.
return false;
}
if (needs_full_padding) {
needs_full_padding_ = true;
}
return true;
}
bool QuicPacketCreator::HasRoomForStreamFrame(QuicStreamId id,
QuicStreamOffset offset,
size_t data_size) {
const size_t min_stream_frame_size = QuicFramer::GetMinStreamFrameSize(
framer_->transport_version(), id, offset, /*last_frame_in_packet=*/true,
data_size);
if (BytesFree() > min_stream_frame_size) {
return true;
}
if (!RemoveSoftMaxPacketLength()) {
return false;
}
return BytesFree() > min_stream_frame_size;
}
bool QuicPacketCreator::HasRoomForMessageFrame(QuicByteCount length) {
const size_t message_frame_size = QuicFramer::GetMessageFrameSize(
framer_->transport_version(), /*last_frame_in_packet=*/true, length);
if (BytesFree() >= message_frame_size) {
return true;
}
if (!RemoveSoftMaxPacketLength()) {
return false;
}
return BytesFree() >= message_frame_size;
}
// TODO(fkastenholz): this method should not use constant values for
// the last-frame-in-packet and data-length parameters to
// GetMinStreamFrameSize. Proper values should be plumbed in from
// higher up. This was left this way for now for a few reasons. First,
// higher up calls to StreamFramePacketOverhead() do not always know
// this information, leading to a cascade of changes and B) the
// higher-up software does not always loop, calling
// StreamFramePacketOverhead() once for every packet -- eg there is
// a test in quic_connection_test that calls it once and assumes that
// the value is the same for all packets.
// static
size_t QuicPacketCreator::StreamFramePacketOverhead(
QuicTransportVersion version,
QuicConnectionIdLength destination_connection_id_length,
QuicConnectionIdLength source_connection_id_length,
bool include_version,
bool include_diversification_nonce,
QuicPacketNumberLength packet_number_length,
QuicVariableLengthIntegerLength retry_token_length_length,
QuicVariableLengthIntegerLength length_length,
QuicStreamOffset offset) {
return GetPacketHeaderSize(version, destination_connection_id_length,
source_connection_id_length, include_version,
include_diversification_nonce,
packet_number_length, retry_token_length_length, 0,
length_length) +
// Assumes this is a packet with a single stream frame in it. Since
// last_frame_in_packet is set true, the size of the length field is
// not included in the calculation. This is OK because in other places
// in the code, the logic adds back 2 (the size of the Google QUIC
// length) when a frame is not the last frame of the packet. This is
// also acceptable for IETF Quic; even though the length field could be
// 8 bytes long, in practice it will not be longer than 2 bytes (enough
// to encode 16K). A length that would be encoded in 2 bytes (0xfff)
// is passed just for cleanliness.
//
// TODO(fkastenholz): This is very hacky and feels brittle. Ideally we
// would calculate the correct lengths at the correct time, based on
// the state at that time/place.
QuicFramer::GetMinStreamFrameSize(version, 1u, offset, true,
kMaxOutgoingPacketSize);
}
void QuicPacketCreator::CreateStreamFrame(QuicStreamId id,
size_t data_size,
QuicStreamOffset offset,
bool fin,
QuicFrame* frame) {
DCHECK_GT(
max_packet_length_,
StreamFramePacketOverhead(
framer_->transport_version(), GetDestinationConnectionIdLength(),
GetSourceConnectionIdLength(), kIncludeVersion,
IncludeNonceInPublicHeader(), PACKET_6BYTE_PACKET_NUMBER,
GetRetryTokenLengthLength(), GetLengthLength(), offset));
QUIC_BUG_IF(!HasRoomForStreamFrame(id, offset, data_size))
<< "No room for Stream frame, BytesFree: " << BytesFree()
<< " MinStreamFrameSize: "
<< QuicFramer::GetMinStreamFrameSize(framer_->transport_version(), id,
offset, true, data_size);
QUIC_BUG_IF(data_size == 0 && !fin)
<< "Creating a stream frame for stream ID:" << id
<< " with no data or fin.";
size_t min_frame_size = QuicFramer::GetMinStreamFrameSize(
framer_->transport_version(), id, offset,
/* last_frame_in_packet= */ true, data_size);
size_t bytes_consumed =
std::min<size_t>(BytesFree() - min_frame_size, data_size);
bool set_fin = fin && bytes_consumed == data_size; // Last frame.
*frame = QuicFrame(QuicStreamFrame(id, set_fin, offset, bytes_consumed));
}
bool QuicPacketCreator::CreateCryptoFrame(EncryptionLevel level,
size_t write_length,
QuicStreamOffset offset,
QuicFrame* frame) {
size_t min_frame_size =
QuicFramer::GetMinCryptoFrameSize(write_length, offset);
if (BytesFree() <= min_frame_size &&
(!RemoveSoftMaxPacketLength() || BytesFree() <= min_frame_size)) {
return false;
}
size_t max_write_length = BytesFree() - min_frame_size;
size_t bytes_consumed = std::min<size_t>(max_write_length, write_length);
*frame = QuicFrame(new QuicCryptoFrame(level, offset, bytes_consumed));
return true;
}
void QuicPacketCreator::FlushCurrentPacket() {
if (!HasPendingFrames() && pending_padding_bytes_ == 0) {
return;
}
QUIC_CACHELINE_ALIGNED char stack_buffer[kMaxOutgoingPacketSize];
char* serialized_packet_buffer = delegate_->GetPacketBuffer();
if (serialized_packet_buffer == nullptr) {
serialized_packet_buffer = stack_buffer;
}
SerializePacket(serialized_packet_buffer, kMaxOutgoingPacketSize);
OnSerializedPacket();
}
void QuicPacketCreator::OnSerializedPacket() {
if (packet_.encrypted_buffer == nullptr) {
const std::string error_details = "Failed to SerializePacket.";
QUIC_BUG << error_details;
delegate_->OnUnrecoverableError(QUIC_FAILED_TO_SERIALIZE_PACKET,
error_details);
return;
}
SerializedPacket packet(std::move(packet_));
ClearPacket();
RemoveSoftMaxPacketLength();
delegate_->OnSerializedPacket(&packet);
}
void QuicPacketCreator::ClearPacket() {
packet_.has_ack = false;
packet_.has_stop_waiting = false;
packet_.has_crypto_handshake = NOT_HANDSHAKE;
packet_.num_padding_bytes = 0;
packet_.transmission_type = NOT_RETRANSMISSION;
packet_.encrypted_buffer = nullptr;
packet_.encrypted_length = 0;
DCHECK(packet_.retransmittable_frames.empty());
DCHECK(packet_.nonretransmittable_frames.empty());
packet_.largest_acked.Clear();
needs_full_padding_ = false;
}
size_t QuicPacketCreator::ReserializeInitialPacketInCoalescedPacket(
const SerializedPacket& packet,
size_t padding_size,
char* buffer,
size_t buffer_len) {
QUIC_BUG_IF(packet.encryption_level != ENCRYPTION_INITIAL);
QUIC_BUG_IF(packet.nonretransmittable_frames.empty() &&
packet.retransmittable_frames.empty())
<< "Attempt to serialize empty ENCRYPTION_INITIAL packet in coalesced "
"packet";
ScopedPacketContextSwitcher switcher(
packet.packet_number -
1, // -1 because serialize packet increase packet number.
packet.packet_number_length, packet.encryption_level, &packet_);
for (const QuicFrame& frame : packet.nonretransmittable_frames) {
if (!AddFrame(frame, packet.transmission_type)) {
QUIC_BUG << "Failed to serialize frame: " << frame;
return 0;
}
}
for (const QuicFrame& frame : packet.retransmittable_frames) {
if (!AddFrame(frame, packet.transmission_type)) {
QUIC_BUG << "Failed to serialize frame: " << frame;
return 0;
}
}
// Add necessary padding.
if (padding_size > 0) {
QUIC_DVLOG(2) << ENDPOINT << "Add padding of size: " << padding_size;
if (!AddFrame(QuicFrame(QuicPaddingFrame(padding_size)),
packet.transmission_type)) {
QUIC_BUG << "Failed to add padding of size " << padding_size
<< " when serializing ENCRYPTION_INITIAL "
"packet in coalesced packet";
return 0;
}
}
SerializePacket(buffer, buffer_len);
const size_t encrypted_length = packet_.encrypted_length;
// Clear frames in packet_. No need to DeleteFrames since frames are owned by
// initial_packet.
packet_.retransmittable_frames.clear();
packet_.nonretransmittable_frames.clear();
ClearPacket();
return encrypted_length;
}
void QuicPacketCreator::CreateAndSerializeStreamFrame(
QuicStreamId id,
size_t write_length,
QuicStreamOffset iov_offset,
QuicStreamOffset stream_offset,
bool fin,
TransmissionType transmission_type,
size_t* num_bytes_consumed) {
DCHECK(queued_frames_.empty());
// Write out the packet header
QuicPacketHeader header;
FillPacketHeader(&header);
QUIC_CACHELINE_ALIGNED char stack_buffer[kMaxOutgoingPacketSize];
char* encrypted_buffer = delegate_->GetPacketBuffer();
if (encrypted_buffer == nullptr) {
encrypted_buffer = stack_buffer;
}
QuicDataWriter writer(kMaxOutgoingPacketSize, encrypted_buffer);
size_t length_field_offset = 0;
if (!framer_->AppendPacketHeader(header, &writer, &length_field_offset)) {
QUIC_BUG << "AppendPacketHeader failed";
return;
}
// Create a Stream frame with the remaining space.
QUIC_BUG_IF(iov_offset == write_length && !fin)
<< "Creating a stream frame with no data or fin.";
const size_t remaining_data_size = write_length - iov_offset;
size_t min_frame_size = QuicFramer::GetMinStreamFrameSize(
framer_->transport_version(), id, stream_offset,
/* last_frame_in_packet= */ true, remaining_data_size);
size_t available_size =
max_plaintext_size_ - writer.length() - min_frame_size;
size_t bytes_consumed = std::min<size_t>(available_size, remaining_data_size);
size_t plaintext_bytes_written = min_frame_size + bytes_consumed;
bool needs_padding = false;
if (plaintext_bytes_written < MinPlaintextPacketSize(framer_->version())) {
needs_padding = true;
// Recalculate sizes with the stream frame not being marked as the last
// frame in the packet.
min_frame_size = QuicFramer::GetMinStreamFrameSize(
framer_->transport_version(), id, stream_offset,
/* last_frame_in_packet= */ false, remaining_data_size);
available_size = max_plaintext_size_ - writer.length() - min_frame_size;
bytes_consumed = std::min<size_t>(available_size, remaining_data_size);
plaintext_bytes_written = min_frame_size + bytes_consumed;
}
const bool set_fin = fin && (bytes_consumed == remaining_data_size);
QuicStreamFrame frame(id, set_fin, stream_offset, bytes_consumed);
if (debug_delegate_ != nullptr) {
debug_delegate_->OnFrameAddedToPacket(QuicFrame(frame));
}
QUIC_DVLOG(1) << ENDPOINT << "Adding frame: " << frame;
QUIC_DVLOG(2) << ENDPOINT << "Serializing stream packet " << header << frame;
// TODO(ianswett): AppendTypeByte and AppendStreamFrame could be optimized
// into one method that takes a QuicStreamFrame, if warranted.
bool omit_frame_length = !needs_padding;
if (!framer_->AppendTypeByte(QuicFrame(frame), omit_frame_length, &writer)) {
QUIC_BUG << "AppendTypeByte failed";
return;
}
if (!framer_->AppendStreamFrame(frame, omit_frame_length, &writer)) {
QUIC_BUG << "AppendStreamFrame failed";
return;
}
if (needs_padding &&
plaintext_bytes_written < MinPlaintextPacketSize(framer_->version()) &&
!writer.WritePaddingBytes(MinPlaintextPacketSize(framer_->version()) -
plaintext_bytes_written)) {
QUIC_BUG << "Unable to add padding bytes";
return;
}
if (!framer_->WriteIetfLongHeaderLength(header, &writer, length_field_offset,
packet_.encryption_level)) {
return;
}
packet_.transmission_type = transmission_type;
size_t encrypted_length = framer_->EncryptInPlace(
packet_.encryption_level, packet_.packet_number,
GetStartOfEncryptedData(framer_->transport_version(), header),
writer.length(), kMaxOutgoingPacketSize, encrypted_buffer);
if (encrypted_length == 0) {
QUIC_BUG << "Failed to encrypt packet number " << header.packet_number;
return;
}
// TODO(ianswett): Optimize the storage so RetransmitableFrames can be
// unioned with a QuicStreamFrame and a UniqueStreamBuffer.
*num_bytes_consumed = bytes_consumed;
packet_size_ = 0;
packet_.encrypted_buffer = encrypted_buffer;
packet_.encrypted_length = encrypted_length;
packet_.retransmittable_frames.push_back(QuicFrame(frame));
OnSerializedPacket();
}
bool QuicPacketCreator::HasPendingFrames() const {
return !queued_frames_.empty();
}
bool QuicPacketCreator::HasPendingRetransmittableFrames() const {
return !packet_.retransmittable_frames.empty();
}
bool QuicPacketCreator::HasPendingStreamFramesOfStream(QuicStreamId id) const {
for (const auto& frame : packet_.retransmittable_frames) {
if (frame.type == STREAM_FRAME && frame.stream_frame.stream_id == id) {
return true;
}
}
return false;
}
size_t QuicPacketCreator::ExpansionOnNewFrame() const {
// If the last frame in the packet is a message frame, then it will expand to
// include the varint message length when a new frame is added.
const bool has_trailing_message_frame =
!queued_frames_.empty() && queued_frames_.back().type == MESSAGE_FRAME;
if (has_trailing_message_frame) {
return QuicDataWriter::GetVarInt62Len(
queued_frames_.back().message_frame->message_length);
}
// If the last frame in the packet is a stream frame, then it will expand to
// include the stream_length field when a new frame is added.
const bool has_trailing_stream_frame =
!queued_frames_.empty() && queued_frames_.back().type == STREAM_FRAME;
if (!has_trailing_stream_frame) {
return 0;
}
if (VersionHasIetfQuicFrames(framer_->transport_version())) {
return QuicDataWriter::GetVarInt62Len(
queued_frames_.back().stream_frame.data_length);
}
return kQuicStreamPayloadLengthSize;
}
size_t QuicPacketCreator::BytesFree() {
DCHECK_GE(max_plaintext_size_, PacketSize());
return max_plaintext_size_ -
std::min(max_plaintext_size_, PacketSize() + ExpansionOnNewFrame());
}
size_t QuicPacketCreator::PacketSize() {
if (!queued_frames_.empty()) {
return packet_size_;
}
packet_size_ = PacketHeaderSize();
return packet_size_;
}
bool QuicPacketCreator::AddSavedFrame(const QuicFrame& frame,
TransmissionType transmission_type) {
return AddFrame(frame, transmission_type);
}
bool QuicPacketCreator::AddPaddedSavedFrame(
const QuicFrame& frame,
TransmissionType transmission_type) {
if (AddFrame(frame, transmission_type)) {
needs_full_padding_ = true;
return true;
}
return false;
}
void QuicPacketCreator::SerializePacket(char* encrypted_buffer,
size_t encrypted_buffer_len) {
DCHECK_LT(0u, encrypted_buffer_len);
QUIC_BUG_IF(queued_frames_.empty() && pending_padding_bytes_ == 0)
<< "Attempt to serialize empty packet";
QuicPacketHeader header;
// FillPacketHeader increments packet_number_.
FillPacketHeader(&header);
MaybeAddPadding();
QUIC_DVLOG(2) << ENDPOINT << "Serializing packet " << header
<< QuicFramesToString(queued_frames_);
DCHECK_GE(max_plaintext_size_, packet_size_);
// Use the packet_size_ instead of the buffer size to ensure smaller
// packet sizes are properly used.
size_t length =
framer_->BuildDataPacket(header, queued_frames_, encrypted_buffer,
packet_size_, packet_.encryption_level);
if (length == 0) {
QUIC_BUG << "Failed to serialize " << queued_frames_.size() << " frames.";
return;
}
// ACK Frames will be truncated due to length only if they're the only frame
// in the packet, and if packet_size_ was set to max_plaintext_size_. If
// truncation due to length occurred, then GetSerializedFrameLength will have
// returned all bytes free.
bool possibly_truncated_by_length = packet_size_ == max_plaintext_size_ &&
queued_frames_.size() == 1 &&
queued_frames_.back().type == ACK_FRAME;
// Because of possible truncation, we can't be confident that our
// packet size calculation worked correctly.
if (!possibly_truncated_by_length) {
DCHECK_EQ(packet_size_, length);
}
const size_t encrypted_length = framer_->EncryptInPlace(
packet_.encryption_level, packet_.packet_number,
GetStartOfEncryptedData(framer_->transport_version(), header), length,
encrypted_buffer_len, encrypted_buffer);
if (encrypted_length == 0) {
QUIC_BUG << "Failed to encrypt packet number " << packet_.packet_number;
return;
}
packet_size_ = 0;
queued_frames_.clear();
packet_.encrypted_buffer = encrypted_buffer;
packet_.encrypted_length = encrypted_length;
}
std::unique_ptr<QuicEncryptedPacket>
QuicPacketCreator::SerializeVersionNegotiationPacket(
bool ietf_quic,
bool use_length_prefix,
const ParsedQuicVersionVector& supported_versions) {
DCHECK_EQ(Perspective::IS_SERVER, framer_->perspective());
std::unique_ptr<QuicEncryptedPacket> encrypted =
QuicFramer::BuildVersionNegotiationPacket(
server_connection_id_, client_connection_id_, ietf_quic,
use_length_prefix, supported_versions);
DCHECK(encrypted);
DCHECK_GE(max_packet_length_, encrypted->length());
return encrypted;
}
OwningSerializedPacketPointer
QuicPacketCreator::SerializeConnectivityProbingPacket() {
QUIC_BUG_IF(VersionHasIetfQuicFrames(framer_->transport_version()))
<< "Must not be version 99 to serialize padded ping connectivity probe";
RemoveSoftMaxPacketLength();
QuicPacketHeader header;
// FillPacketHeader increments packet_number_.
FillPacketHeader(&header);
QUIC_DVLOG(2) << ENDPOINT << "Serializing connectivity probing packet "
<< header;
std::unique_ptr<char[]> buffer(new char[kMaxOutgoingPacketSize]);
size_t length = BuildConnectivityProbingPacket(
header, buffer.get(), max_plaintext_size_, packet_.encryption_level);
DCHECK(length);
const size_t encrypted_length = framer_->EncryptInPlace(
packet_.encryption_level, packet_.packet_number,
GetStartOfEncryptedData(framer_->transport_version(), header), length,
kMaxOutgoingPacketSize, buffer.get());
DCHECK(encrypted_length);
OwningSerializedPacketPointer serialize_packet(new SerializedPacket(
header.packet_number, header.packet_number_length, buffer.release(),
encrypted_length, /*has_ack=*/false, /*has_stop_waiting=*/false));
serialize_packet->encryption_level = packet_.encryption_level;
serialize_packet->transmission_type = NOT_RETRANSMISSION;
return serialize_packet;
}
OwningSerializedPacketPointer
QuicPacketCreator::SerializePathChallengeConnectivityProbingPacket(
QuicPathFrameBuffer* payload) {
QUIC_BUG_IF(!VersionHasIetfQuicFrames(framer_->transport_version()))
<< "Must be version 99 to serialize path challenge connectivity probe, "
"is version "
<< framer_->transport_version();
RemoveSoftMaxPacketLength();
QuicPacketHeader header;
// FillPacketHeader increments packet_number_.
FillPacketHeader(&header);
QUIC_DVLOG(2) << ENDPOINT << "Serializing path challenge packet " << header;
std::unique_ptr<char[]> buffer(new char[kMaxOutgoingPacketSize]);
size_t length = BuildPaddedPathChallengePacket(
header, buffer.get(), max_plaintext_size_, payload, random_,
packet_.encryption_level);
DCHECK(length);
const size_t encrypted_length = framer_->EncryptInPlace(
packet_.encryption_level, packet_.packet_number,
GetStartOfEncryptedData(framer_->transport_version(), header), length,
kMaxOutgoingPacketSize, buffer.get());
DCHECK(encrypted_length);
OwningSerializedPacketPointer serialize_packet(new SerializedPacket(
header.packet_number, header.packet_number_length, buffer.release(),
encrypted_length, /*has_ack=*/false, /*has_stop_waiting=*/false));
serialize_packet->encryption_level = packet_.encryption_level;
serialize_packet->transmission_type = NOT_RETRANSMISSION;
return serialize_packet;
}
OwningSerializedPacketPointer
QuicPacketCreator::SerializePathResponseConnectivityProbingPacket(
const QuicDeque<QuicPathFrameBuffer>& payloads,
const bool is_padded) {
QUIC_BUG_IF(!VersionHasIetfQuicFrames(framer_->transport_version()))
<< "Must be version 99 to serialize path response connectivity probe, is "
"version "
<< framer_->transport_version();
RemoveSoftMaxPacketLength();
QuicPacketHeader header;
// FillPacketHeader increments packet_number_.
FillPacketHeader(&header);
QUIC_DVLOG(2) << ENDPOINT << "Serializing path response packet " << header;
std::unique_ptr<char[]> buffer(new char[kMaxOutgoingPacketSize]);
size_t length =
BuildPathResponsePacket(header, buffer.get(), max_plaintext_size_,
payloads, is_padded, packet_.encryption_level);
DCHECK(length);
const size_t encrypted_length = framer_->EncryptInPlace(
packet_.encryption_level, packet_.packet_number,
GetStartOfEncryptedData(framer_->transport_version(), header), length,
kMaxOutgoingPacketSize, buffer.get());
DCHECK(encrypted_length);
OwningSerializedPacketPointer serialize_packet(new SerializedPacket(
header.packet_number, header.packet_number_length, buffer.release(),
encrypted_length, /*has_ack=*/false, /*has_stop_waiting=*/false));
serialize_packet->encryption_level = packet_.encryption_level;
serialize_packet->transmission_type = NOT_RETRANSMISSION;
return serialize_packet;
}
size_t QuicPacketCreator::BuildPaddedPathChallengePacket(
const QuicPacketHeader& header,
char* buffer,
size_t packet_length,
QuicPathFrameBuffer* payload,
QuicRandom* randomizer,
EncryptionLevel level) {
DCHECK(VersionHasIetfQuicFrames(framer_->transport_version()));
QuicFrames frames;
// Write a PATH_CHALLENGE frame, which has a random 8-byte payload
randomizer->RandBytes(payload->data(), payload->size());
QuicPathChallengeFrame path_challenge_frame(0, *payload);
frames.push_back(QuicFrame(&path_challenge_frame));
if (debug_delegate_ != nullptr) {
debug_delegate_->OnFrameAddedToPacket(QuicFrame(&path_challenge_frame));
}
// Add padding to the rest of the packet in order to assess Path MTU
// characteristics.
QuicPaddingFrame padding_frame;
frames.push_back(QuicFrame(padding_frame));
return framer_->BuildDataPacket(header, frames, buffer, packet_length, level);
}
size_t QuicPacketCreator::BuildPathResponsePacket(
const QuicPacketHeader& header,
char* buffer,
size_t packet_length,
const QuicDeque<QuicPathFrameBuffer>& payloads,
const bool is_padded,
EncryptionLevel level) {
if (payloads.empty()) {
QUIC_BUG
<< "Attempt to generate connectivity response with no request payloads";
return 0;
}
DCHECK(VersionHasIetfQuicFrames(framer_->transport_version()));
std::vector<std::unique_ptr<QuicPathResponseFrame>> path_response_frames;
for (const QuicPathFrameBuffer& payload : payloads) {
// Note that the control frame ID can be 0 since this is not retransmitted.
path_response_frames.push_back(
std::make_unique<QuicPathResponseFrame>(0, payload));
}
QuicFrames frames;
for (const std::unique_ptr<QuicPathResponseFrame>& path_response_frame :
path_response_frames) {
frames.push_back(QuicFrame(path_response_frame.get()));
if (debug_delegate_ != nullptr) {
debug_delegate_->OnFrameAddedToPacket(
QuicFrame(path_response_frame.get()));
}
}
if (is_padded) {
// Add padding to the rest of the packet in order to assess Path MTU
// characteristics.
QuicPaddingFrame padding_frame;
frames.push_back(QuicFrame(padding_frame));
}
return framer_->BuildDataPacket(header, frames, buffer, packet_length, level);
}
size_t QuicPacketCreator::BuildConnectivityProbingPacket(
const QuicPacketHeader& header,
char* buffer,
size_t packet_length,
EncryptionLevel level) {
QuicFrames frames;
// Write a PING frame, which has no data payload.
QuicPingFrame ping_frame;
frames.push_back(QuicFrame(ping_frame));
// Add padding to the rest of the packet.
QuicPaddingFrame padding_frame;
frames.push_back(QuicFrame(padding_frame));
return framer_->BuildDataPacket(header, frames, buffer, packet_length, level);
}
size_t QuicPacketCreator::SerializeCoalescedPacket(
const QuicCoalescedPacket& coalesced,
char* buffer,
size_t buffer_len) {
QUIC_BUG_IF(packet_.num_padding_bytes != 0);
if (HasPendingFrames()) {
QUIC_BUG << "Try to serialize coalesced packet with pending frames";
return 0;
}
QUIC_BUG_IF(coalesced.length() == 0)
<< "Attempt to serialize empty coalesced packet";
size_t packet_length = 0;
if (coalesced.initial_packet() != nullptr) {
size_t initial_length = ReserializeInitialPacketInCoalescedPacket(
*coalesced.initial_packet(),
/*padding_size=*/coalesced.max_packet_length() - coalesced.length(),
buffer, buffer_len);
if (initial_length == 0) {
QUIC_BUG << "Failed to reserialize ENCRYPTION_INITIAL packet in "
"coalesced packet";
return 0;
}
buffer += initial_length;
buffer_len -= initial_length;
packet_length += initial_length;
}
size_t length_copied = 0;
if (!coalesced.CopyEncryptedBuffers(buffer, buffer_len, &length_copied)) {
return 0;
}
packet_length += length_copied;
QUIC_DVLOG(1) << ENDPOINT
<< "Successfully serialized coalesced packet of length: "
<< packet_length;
return packet_length;
}
// TODO(b/74062209): Make this a public method of framer?
SerializedPacket QuicPacketCreator::NoPacket() {
return SerializedPacket(QuicPacketNumber(), PACKET_1BYTE_PACKET_NUMBER,
nullptr, 0, false, false);
}
QuicConnectionId QuicPacketCreator::GetDestinationConnectionId() const {
if (framer_->perspective() == Perspective::IS_SERVER) {
return client_connection_id_;
}
return server_connection_id_;
}
QuicConnectionId QuicPacketCreator::GetSourceConnectionId() const {
if (framer_->perspective() == Perspective::IS_CLIENT) {
return client_connection_id_;
}
return server_connection_id_;
}
QuicConnectionIdIncluded QuicPacketCreator::GetDestinationConnectionIdIncluded()
const {
// In versions that do not support client connection IDs, the destination
// connection ID is only sent from client to server.
return (framer_->perspective() == Perspective::IS_CLIENT ||
framer_->version().SupportsClientConnectionIds())
? CONNECTION_ID_PRESENT
: CONNECTION_ID_ABSENT;
}
QuicConnectionIdIncluded QuicPacketCreator::GetSourceConnectionIdIncluded()
const {
// Long header packets sent by server include source connection ID.
// Ones sent by the client only include source connection ID if the version
// supports client connection IDs.
if (HasIetfLongHeader() &&
(framer_->perspective() == Perspective::IS_SERVER ||
framer_->version().SupportsClientConnectionIds())) {
return CONNECTION_ID_PRESENT;
}
if (framer_->perspective() == Perspective::IS_SERVER) {
return server_connection_id_included_;
}
return CONNECTION_ID_ABSENT;
}
QuicConnectionIdLength QuicPacketCreator::GetDestinationConnectionIdLength()
const {
DCHECK(QuicUtils::IsConnectionIdValidForVersion(server_connection_id_,
transport_version()));
return GetDestinationConnectionIdIncluded() == CONNECTION_ID_PRESENT
? static_cast<QuicConnectionIdLength>(
GetDestinationConnectionId().length())
: PACKET_0BYTE_CONNECTION_ID;
}
QuicConnectionIdLength QuicPacketCreator::GetSourceConnectionIdLength() const {
DCHECK(QuicUtils::IsConnectionIdValidForVersion(server_connection_id_,
transport_version()));
return GetSourceConnectionIdIncluded() == CONNECTION_ID_PRESENT
? static_cast<QuicConnectionIdLength>(
GetSourceConnectionId().length())
: PACKET_0BYTE_CONNECTION_ID;
}
QuicPacketNumberLength QuicPacketCreator::GetPacketNumberLength() const {
if (HasIetfLongHeader() &&
!framer_->version().SendsVariableLengthPacketNumberInLongHeader()) {
return PACKET_4BYTE_PACKET_NUMBER;
}
return packet_.packet_number_length;
}
size_t QuicPacketCreator::PacketHeaderSize() const {
return GetPacketHeaderSize(
framer_->transport_version(), GetDestinationConnectionIdLength(),
GetSourceConnectionIdLength(), IncludeVersionInHeader(),
IncludeNonceInPublicHeader(), GetPacketNumberLength(),
GetRetryTokenLengthLength(), GetRetryToken().length(), GetLengthLength());
}
QuicVariableLengthIntegerLength QuicPacketCreator::GetRetryTokenLengthLength()
const {
if (QuicVersionHasLongHeaderLengths(framer_->transport_version()) &&
HasIetfLongHeader() &&
EncryptionlevelToLongHeaderType(packet_.encryption_level) == INITIAL) {
return QuicDataWriter::GetVarInt62Len(GetRetryToken().length());
}
return VARIABLE_LENGTH_INTEGER_LENGTH_0;
}
QuicStringPiece QuicPacketCreator::GetRetryToken() const {
if (QuicVersionHasLongHeaderLengths(framer_->transport_version()) &&
HasIetfLongHeader() &&
EncryptionlevelToLongHeaderType(packet_.encryption_level) == INITIAL) {
return retry_token_;
}
return QuicStringPiece();
}
void QuicPacketCreator::SetRetryToken(QuicStringPiece retry_token) {
retry_token_ = std::string(retry_token);
}
bool QuicPacketCreator::ConsumeRetransmittableControlFrame(
const QuicFrame& frame) {
DCHECK(combine_generator_and_creator_);
QUIC_BUG_IF(IsControlFrame(frame.type) && !GetControlFrameId(frame))
<< "Adding a control frame with no control frame id: " << frame;
DCHECK(QuicUtils::IsRetransmittableFrame(frame.type)) << frame;
MaybeBundleAckOpportunistically();
if (HasPendingFrames()) {
if (AddSavedFrame(frame, next_transmission_type_)) {
// There is pending frames and current frame fits.
return true;
}
}
DCHECK(!HasPendingFrames());
if (frame.type != PING_FRAME && frame.type != CONNECTION_CLOSE_FRAME &&
!delegate_->ShouldGeneratePacket(HAS_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
// Do not check congestion window for ping or connection close frames.
return false;
}
const bool success = AddSavedFrame(frame, next_transmission_type_);
QUIC_BUG_IF(!success) << "Failed to add frame:" << frame
<< " transmission_type:" << next_transmission_type_;
return success;
}
QuicConsumedData QuicPacketCreator::ConsumeData(QuicStreamId id,
size_t write_length,
QuicStreamOffset offset,
StreamSendingState state) {
DCHECK(combine_generator_and_creator_);
QUIC_BUG_IF(!flusher_attached_) << "Packet flusher is not attached when "
"generator tries to write stream data.";
bool has_handshake = QuicUtils::IsCryptoStreamId(transport_version(), id);
MaybeBundleAckOpportunistically();
bool fin = state != NO_FIN;
QUIC_BUG_IF(has_handshake && fin)
<< "Handshake packets should never send a fin";
// To make reasoning about crypto frames easier, we don't combine them with
// other retransmittable frames in a single packet.
if (has_handshake && HasPendingRetransmittableFrames()) {
FlushCurrentPacket();
}
size_t total_bytes_consumed = 0;
bool fin_consumed = false;
if (!HasRoomForStreamFrame(id, offset, write_length)) {
FlushCurrentPacket();
}
if (!fin && (write_length == 0)) {
QUIC_BUG << "Attempt to consume empty data without FIN.";
return QuicConsumedData(0, false);
}
// We determine if we can enter the fast path before executing
// the slow path loop.
bool run_fast_path =
!has_handshake && state != FIN_AND_PADDING && !HasPendingFrames() &&
write_length - total_bytes_consumed > kMaxOutgoingPacketSize &&
latched_hard_max_packet_length_ == 0;
while (!run_fast_path && delegate_->ShouldGeneratePacket(
HAS_RETRANSMITTABLE_DATA,
has_handshake ? IS_HANDSHAKE : NOT_HANDSHAKE)) {
QuicFrame frame;
bool needs_full_padding =
has_handshake && fully_pad_crypto_handshake_packets_;
if (!ConsumeDataToFillCurrentPacket(id, write_length - total_bytes_consumed,
offset + total_bytes_consumed, fin,
needs_full_padding,
next_transmission_type_, &frame)) {
// The creator is always flushed if there's not enough room for a new
// stream frame before ConsumeData, so ConsumeData should always succeed.
QUIC_BUG << "Failed to ConsumeData, stream:" << id;
return QuicConsumedData(0, false);
}
// A stream frame is created and added.
size_t bytes_consumed = frame.stream_frame.data_length;
total_bytes_consumed += bytes_consumed;
fin_consumed = fin && total_bytes_consumed == write_length;
if (fin_consumed && state == FIN_AND_PADDING) {
AddRandomPadding();
}
DCHECK(total_bytes_consumed == write_length ||
(bytes_consumed > 0 && HasPendingFrames()));
if (total_bytes_consumed == write_length) {
// We're done writing the data. Exit the loop.
// We don't make this a precondition because we could have 0 bytes of data
// if we're simply writing a fin.
break;
}
FlushCurrentPacket();
run_fast_path =
!has_handshake && state != FIN_AND_PADDING && !HasPendingFrames() &&
write_length - total_bytes_consumed > kMaxOutgoingPacketSize &&
latched_hard_max_packet_length_ == 0;
}
if (run_fast_path) {
return ConsumeDataFastPath(id, write_length, offset, state != NO_FIN,
total_bytes_consumed);
}
// Don't allow the handshake to be bundled with other retransmittable frames.
if (has_handshake) {
FlushCurrentPacket();
}
return QuicConsumedData(total_bytes_consumed, fin_consumed);
}
QuicConsumedData QuicPacketCreator::ConsumeDataFastPath(
QuicStreamId id,
size_t write_length,
QuicStreamOffset offset,
bool fin,
size_t total_bytes_consumed) {
DCHECK(combine_generator_and_creator_);
DCHECK(!QuicUtils::IsCryptoStreamId(transport_version(), id));
while (total_bytes_consumed < write_length &&
delegate_->ShouldGeneratePacket(HAS_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
// Serialize and encrypt the packet.
size_t bytes_consumed = 0;
CreateAndSerializeStreamFrame(id, write_length, total_bytes_consumed,
offset + total_bytes_consumed, fin,
next_transmission_type_, &bytes_consumed);
total_bytes_consumed += bytes_consumed;
}
return QuicConsumedData(total_bytes_consumed,
fin && (total_bytes_consumed == write_length));
}
size_t QuicPacketCreator::ConsumeCryptoData(EncryptionLevel level,
size_t write_length,
QuicStreamOffset offset) {
DCHECK(combine_generator_and_creator_);
QUIC_BUG_IF(!flusher_attached_) << "Packet flusher is not attached when "
"generator tries to write crypto data.";
MaybeBundleAckOpportunistically();
// To make reasoning about crypto frames easier, we don't combine them with
// other retransmittable frames in a single packet.
// TODO(nharper): Once we have separate packet number spaces, everything
// should be driven by encryption level, and we should stop flushing in this
// spot.
if (HasPendingRetransmittableFrames()) {
FlushCurrentPacket();
}
size_t total_bytes_consumed = 0;
while (total_bytes_consumed < write_length) {
QuicFrame frame;
if (!ConsumeCryptoDataToFillCurrentPacket(
level, write_length - total_bytes_consumed,
offset + total_bytes_consumed, fully_pad_crypto_handshake_packets_,
next_transmission_type_, &frame)) {
// The only pending data in the packet is non-retransmittable frames. I'm
// assuming here that they won't occupy so much of the packet that a
// CRYPTO frame won't fit.
QUIC_BUG << "Failed to ConsumeCryptoData at level " << level;
return 0;
}
total_bytes_consumed += frame.crypto_frame->data_length;
FlushCurrentPacket();
}
// Don't allow the handshake to be bundled with other retransmittable frames.
FlushCurrentPacket();
return total_bytes_consumed;
}
void QuicPacketCreator::GenerateMtuDiscoveryPacket(QuicByteCount target_mtu) {
DCHECK(combine_generator_and_creator_);
// MTU discovery frames must be sent by themselves.
if (!CanSetMaxPacketLength()) {
QUIC_BUG << "MTU discovery packets should only be sent when no other "
<< "frames needs to be sent.";
return;
}
const QuicByteCount current_mtu = max_packet_length();
// The MTU discovery frame is allocated on the stack, since it is going to be
// serialized within this function.
QuicMtuDiscoveryFrame mtu_discovery_frame;
QuicFrame frame(mtu_discovery_frame);
// Send the probe packet with the new length.
SetMaxPacketLength(target_mtu);
const bool success = AddPaddedSavedFrame(frame, next_transmission_type_);
FlushCurrentPacket();
// The only reason AddFrame can fail is that the packet is too full to fit in
// a ping. This is not possible for any sane MTU.
QUIC_BUG_IF(!success) << "Failed to send path MTU target_mtu:" << target_mtu
<< " transmission_type:" << next_transmission_type_;
// Reset the packet length back.
SetMaxPacketLength(current_mtu);
}
void QuicPacketCreator::MaybeBundleAckOpportunistically() {
DCHECK(combine_generator_and_creator_);
if (has_ack()) {
// Ack already queued, nothing to do.
return;
}
if (!delegate_->ShouldGeneratePacket(NO_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
return;
}
const bool flushed =
FlushAckFrame(delegate_->MaybeBundleAckOpportunistically());
QUIC_BUG_IF(!flushed) << "Failed to flush ACK frame. encryption_level:"
<< packet_.encryption_level;
}
bool QuicPacketCreator::FlushAckFrame(const QuicFrames& frames) {
DCHECK(combine_generator_and_creator_);
QUIC_BUG_IF(!flusher_attached_) << "Packet flusher is not attached when "
"generator tries to send ACK frame.";
for (const auto& frame : frames) {
DCHECK(frame.type == ACK_FRAME || frame.type == STOP_WAITING_FRAME);
if (HasPendingFrames()) {
if (AddSavedFrame(frame, next_transmission_type_)) {
// There is pending frames and current frame fits.
continue;
}
}
DCHECK(!HasPendingFrames());
// There is no pending frames, consult the delegate whether a packet can be
// generated.
if (!delegate_->ShouldGeneratePacket(NO_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
return false;
}
const bool success = AddSavedFrame(frame, next_transmission_type_);
QUIC_BUG_IF(!success) << "Failed to flush " << frame;
}
return true;
}
void QuicPacketCreator::AddRandomPadding() {
DCHECK(combine_generator_and_creator_);
AddPendingPadding(random_->RandUint64() % kMaxNumRandomPaddingBytes + 1);
}
void QuicPacketCreator::AttachPacketFlusher() {
DCHECK(combine_generator_and_creator_);
flusher_attached_ = true;
if (!write_start_packet_number_.IsInitialized()) {
write_start_packet_number_ = NextSendingPacketNumber();
}
}
void QuicPacketCreator::Flush() {
DCHECK(combine_generator_and_creator_);
FlushCurrentPacket();
SendRemainingPendingPadding();
flusher_attached_ = false;
if (GetQuicFlag(FLAGS_quic_export_server_num_packets_per_write_histogram)) {
if (!write_start_packet_number_.IsInitialized()) {
QUIC_BUG << "write_start_packet_number is not initialized";
return;
}
QUIC_SERVER_HISTOGRAM_COUNTS(
"quic_server_num_written_packets_per_write",
NextSendingPacketNumber() - write_start_packet_number_, 1, 200, 50,
"Number of QUIC packets written per write operation");
}
write_start_packet_number_.Clear();
}
void QuicPacketCreator::SendRemainingPendingPadding() {
DCHECK(combine_generator_and_creator_);
while (
pending_padding_bytes() > 0 && !HasPendingFrames() &&
delegate_->ShouldGeneratePacket(NO_RETRANSMITTABLE_DATA, NOT_HANDSHAKE)) {
FlushCurrentPacket();
}
}
void QuicPacketCreator::SetServerConnectionIdLength(uint32_t length) {
DCHECK(combine_generator_and_creator_);
if (length == 0) {
SetServerConnectionIdIncluded(CONNECTION_ID_ABSENT);
} else {
SetServerConnectionIdIncluded(CONNECTION_ID_PRESENT);
}
}
void QuicPacketCreator::SetTransmissionType(TransmissionType type) {
DCHECK(combine_generator_and_creator_);
next_transmission_type_ = type;
}
MessageStatus QuicPacketCreator::AddMessageFrame(QuicMessageId message_id,
QuicMemSliceSpan message) {
DCHECK(combine_generator_and_creator_);
QUIC_BUG_IF(!flusher_attached_) << "Packet flusher is not attached when "
"generator tries to add message frame.";
MaybeBundleAckOpportunistically();
const QuicByteCount message_length = message.total_length();
if (message_length > GetCurrentLargestMessagePayload()) {
return MESSAGE_STATUS_TOO_LARGE;
}
if (!HasRoomForMessageFrame(message_length)) {
FlushCurrentPacket();
}
QuicMessageFrame* frame = new QuicMessageFrame(message_id, message);
const bool success = AddSavedFrame(QuicFrame(frame), next_transmission_type_);
if (!success) {
QUIC_BUG << "Failed to send message " << message_id;
delete frame;
return MESSAGE_STATUS_INTERNAL_ERROR;
}
return MESSAGE_STATUS_SUCCESS;
}
QuicVariableLengthIntegerLength QuicPacketCreator::GetLengthLength() const {
if (QuicVersionHasLongHeaderLengths(framer_->transport_version()) &&
HasIetfLongHeader()) {
QuicLongHeaderType long_header_type =
EncryptionlevelToLongHeaderType(packet_.encryption_level);
if (long_header_type == INITIAL || long_header_type == ZERO_RTT_PROTECTED ||
long_header_type == HANDSHAKE) {
return VARIABLE_LENGTH_INTEGER_LENGTH_2;
}
}
return VARIABLE_LENGTH_INTEGER_LENGTH_0;
}
void QuicPacketCreator::FillPacketHeader(QuicPacketHeader* header) {
header->destination_connection_id = GetDestinationConnectionId();
header->destination_connection_id_included =
GetDestinationConnectionIdIncluded();
header->source_connection_id = GetSourceConnectionId();
header->source_connection_id_included = GetSourceConnectionIdIncluded();
header->reset_flag = false;
header->version_flag = IncludeVersionInHeader();
if (IncludeNonceInPublicHeader()) {
DCHECK_EQ(Perspective::IS_SERVER, framer_->perspective());
header->nonce = &diversification_nonce_;
} else {
header->nonce = nullptr;
}
packet_.packet_number = NextSendingPacketNumber();
header->packet_number = packet_.packet_number;
header->packet_number_length = GetPacketNumberLength();
header->retry_token_length_length = GetRetryTokenLengthLength();
header->retry_token = GetRetryToken();
header->length_length = GetLengthLength();
header->remaining_packet_length = 0;
if (!HasIetfLongHeader()) {
return;
}
header->long_packet_type =
EncryptionlevelToLongHeaderType(packet_.encryption_level);
}
bool QuicPacketCreator::AddFrame(const QuicFrame& frame,
TransmissionType transmission_type) {
QUIC_DVLOG(1) << ENDPOINT << "Adding frame with transmission type "
<< TransmissionTypeToString(transmission_type) << ": " << frame;
if (frame.type == STREAM_FRAME &&
!QuicUtils::IsCryptoStreamId(framer_->transport_version(),
frame.stream_frame.stream_id) &&
(packet_.encryption_level == ENCRYPTION_INITIAL ||
packet_.encryption_level == ENCRYPTION_HANDSHAKE)) {
const std::string error_details =
QuicStrCat("Cannot send stream data with level: ",
EncryptionLevelToString(packet_.encryption_level));
QUIC_BUG << error_details;
delegate_->OnUnrecoverableError(
QUIC_ATTEMPT_TO_SEND_UNENCRYPTED_STREAM_DATA, error_details);
return false;
}
if (GetQuicReloadableFlag(quic_coalesce_stream_frames) &&
frame.type == STREAM_FRAME &&
MaybeCoalesceStreamFrame(frame.stream_frame)) {
QUIC_RELOADABLE_FLAG_COUNT(quic_coalesce_stream_frames);
return true;
}
size_t frame_len = framer_->GetSerializedFrameLength(
frame, BytesFree(), queued_frames_.empty(),
/* last_frame_in_packet= */ true, GetPacketNumberLength());
if (frame_len == 0 && RemoveSoftMaxPacketLength()) {
// Remove soft max_packet_length and retry.
frame_len = framer_->GetSerializedFrameLength(
frame, BytesFree(), queued_frames_.empty(),
/* last_frame_in_packet= */ true, GetPacketNumberLength());
}
if (frame_len == 0) {
// Current open packet is full.
FlushCurrentPacket();
return false;
}
DCHECK_LT(0u, packet_size_);
packet_size_ += ExpansionOnNewFrame() + frame_len;
if (QuicUtils::IsRetransmittableFrame(frame.type)) {
packet_.retransmittable_frames.push_back(frame);
queued_frames_.push_back(frame);
if (QuicUtils::IsHandshakeFrame(frame, framer_->transport_version())) {
packet_.has_crypto_handshake = IS_HANDSHAKE;
}
} else {
if (populate_nonretransmittable_frames_) {
if (frame.type == PADDING_FRAME &&
frame.padding_frame.num_padding_bytes == -1) {
// Populate the actual length of full padding frame, such that one can
// know how much padding is actually added.
packet_.nonretransmittable_frames.push_back(
QuicFrame(QuicPaddingFrame(frame_len)));
} else {
packet_.nonretransmittable_frames.push_back(frame);
}
}
queued_frames_.push_back(frame);
}
if (frame.type == ACK_FRAME) {
packet_.has_ack = true;
packet_.largest_acked = LargestAcked(*frame.ack_frame);
}
if (frame.type == STOP_WAITING_FRAME) {
packet_.has_stop_waiting = true;
}
if (debug_delegate_ != nullptr) {
debug_delegate_->OnFrameAddedToPacket(frame);
}
// Packet transmission type is determined by the last added retransmittable
// frame.
if (QuicUtils::IsRetransmittableFrame(frame.type)) {
packet_.transmission_type = transmission_type;
}
return true;
}
bool QuicPacketCreator::MaybeCoalesceStreamFrame(const QuicStreamFrame& frame) {
if (queued_frames_.empty() || queued_frames_.back().type != STREAM_FRAME) {
return false;
}
QuicStreamFrame* candidate = &queued_frames_.back().stream_frame;
if (candidate->stream_id != frame.stream_id ||
candidate->offset + candidate->data_length != frame.offset ||
frame.data_length > BytesFree()) {
return false;
}
candidate->data_length += frame.data_length;
candidate->fin = frame.fin;
// The back of retransmittable frames must be the same as the original
// queued frames' back.
DCHECK_EQ(packet_.retransmittable_frames.back().type, STREAM_FRAME);
QuicStreamFrame* retransmittable =
&packet_.retransmittable_frames.back().stream_frame;
DCHECK_EQ(retransmittable->stream_id, frame.stream_id);
DCHECK_EQ(retransmittable->offset + retransmittable->data_length,
frame.offset);
retransmittable->data_length = candidate->data_length;
retransmittable->fin = candidate->fin;
packet_size_ += frame.data_length;
if (debug_delegate_ != nullptr) {
debug_delegate_->OnStreamFrameCoalesced(*candidate);
}
return true;
}
bool QuicPacketCreator::RemoveSoftMaxPacketLength() {
if (latched_hard_max_packet_length_ == 0) {
return false;
}
if (!CanSetMaxPacketLength()) {
return false;
}
QUIC_DVLOG(1) << "Restoring max packet length to: "
<< latched_hard_max_packet_length_;
SetMaxPacketLength(latched_hard_max_packet_length_);
// Reset latched_max_packet_length_.
latched_hard_max_packet_length_ = 0;
return true;
}
void QuicPacketCreator::MaybeAddPadding() {
// The current packet should have no padding bytes because padding is only
// added when this method is called just before the packet is serialized.
DCHECK_EQ(0, packet_.num_padding_bytes);
if (BytesFree() == 0) {
// Don't pad full packets.
return;
}
if (packet_.transmission_type == PROBING_RETRANSMISSION) {
needs_full_padding_ = true;
}
// Header protection requires a minimum plaintext packet size.
size_t extra_padding_bytes = 0;
if (framer_->version().HasHeaderProtection()) {
size_t frame_bytes = PacketSize() - PacketHeaderSize();
if (frame_bytes + pending_padding_bytes_ <
MinPlaintextPacketSize(framer_->version()) &&
!needs_full_padding_) {
extra_padding_bytes =
MinPlaintextPacketSize(framer_->version()) - frame_bytes;
}
}
if (!needs_full_padding_ && pending_padding_bytes_ == 0 &&
extra_padding_bytes == 0) {
// Do not need padding.
return;
}
int padding_bytes = -1;
if (needs_full_padding_) {
// Full padding does not consume pending padding bytes.
packet_.num_padding_bytes = -1;
} else {
packet_.num_padding_bytes =
std::min<int16_t>(pending_padding_bytes_, BytesFree());
pending_padding_bytes_ -= packet_.num_padding_bytes;
padding_bytes =
std::max<int16_t>(packet_.num_padding_bytes, extra_padding_bytes);
}
bool success = AddFrame(QuicFrame(QuicPaddingFrame(padding_bytes)),
packet_.transmission_type);
QUIC_BUG_IF(!success) << "Failed to add padding_bytes: " << padding_bytes
<< " transmission_type: "
<< TransmissionTypeToString(packet_.transmission_type);
}
bool QuicPacketCreator::IncludeNonceInPublicHeader() const {
return have_diversification_nonce_ &&
packet_.encryption_level == ENCRYPTION_ZERO_RTT;
}
bool QuicPacketCreator::IncludeVersionInHeader() const {
if (VersionHasIetfInvariantHeader(framer_->transport_version())) {
return packet_.encryption_level < ENCRYPTION_FORWARD_SECURE;
}
return send_version_in_packet_;
}
void QuicPacketCreator::AddPendingPadding(QuicByteCount size) {
pending_padding_bytes_ += size;
}
bool QuicPacketCreator::StreamFrameIsClientHello(
const QuicStreamFrame& frame) const {
if (framer_->perspective() == Perspective::IS_SERVER ||
!QuicUtils::IsCryptoStreamId(framer_->transport_version(),
frame.stream_id)) {
return false;
}
// The ClientHello is always sent with INITIAL encryption.
return packet_.encryption_level == ENCRYPTION_INITIAL;
}
void QuicPacketCreator::SetServerConnectionIdIncluded(
QuicConnectionIdIncluded server_connection_id_included) {
DCHECK(server_connection_id_included == CONNECTION_ID_PRESENT ||
server_connection_id_included == CONNECTION_ID_ABSENT);
DCHECK(framer_->perspective() == Perspective::IS_SERVER ||
server_connection_id_included != CONNECTION_ID_ABSENT);
server_connection_id_included_ = server_connection_id_included;
}
void QuicPacketCreator::SetServerConnectionId(
QuicConnectionId server_connection_id) {
server_connection_id_ = server_connection_id;
}
void QuicPacketCreator::SetClientConnectionId(
QuicConnectionId client_connection_id) {
DCHECK(client_connection_id.IsEmpty() ||
framer_->version().SupportsClientConnectionIds());
client_connection_id_ = client_connection_id;
}
QuicPacketLength QuicPacketCreator::GetCurrentLargestMessagePayload() const {
if (!VersionSupportsMessageFrames(framer_->transport_version())) {
return 0;
}
const size_t packet_header_size = GetPacketHeaderSize(
framer_->transport_version(), GetDestinationConnectionIdLength(),
GetSourceConnectionIdLength(), IncludeVersionInHeader(),
IncludeNonceInPublicHeader(), GetPacketNumberLength(),
// No Retry token on packets containing application data.
VARIABLE_LENGTH_INTEGER_LENGTH_0, 0, GetLengthLength());
// This is the largest possible message payload when the length field is
// omitted.
size_t max_plaintext_size =
latched_hard_max_packet_length_ == 0
? max_plaintext_size_
: framer_->GetMaxPlaintextSize(latched_hard_max_packet_length_);
return max_plaintext_size -
std::min(max_plaintext_size, packet_header_size + kQuicFrameTypeSize);
}
QuicPacketLength QuicPacketCreator::GetGuaranteedLargestMessagePayload() const {
if (!VersionSupportsMessageFrames(framer_->transport_version())) {
return 0;
}
// QUIC Crypto server packets may include a diversification nonce.
const bool may_include_nonce =
framer_->version().handshake_protocol == PROTOCOL_QUIC_CRYPTO &&
framer_->perspective() == Perspective::IS_SERVER;
// IETF QUIC long headers include a length on client 0RTT packets.
QuicVariableLengthIntegerLength length_length =
VARIABLE_LENGTH_INTEGER_LENGTH_0;
if (framer_->perspective() == Perspective::IS_CLIENT) {
length_length = VARIABLE_LENGTH_INTEGER_LENGTH_2;
}
if (!QuicVersionHasLongHeaderLengths(framer_->transport_version())) {
length_length = VARIABLE_LENGTH_INTEGER_LENGTH_0;
}
const size_t packet_header_size = GetPacketHeaderSize(
framer_->transport_version(), GetDestinationConnectionIdLength(),
// Assume CID lengths don't change, but version may be present.
GetSourceConnectionIdLength(), kIncludeVersion, may_include_nonce,
PACKET_4BYTE_PACKET_NUMBER,
// No Retry token on packets containing application data.
VARIABLE_LENGTH_INTEGER_LENGTH_0, 0, length_length);
// This is the largest possible message payload when the length field is
// omitted.
size_t max_plaintext_size =
latched_hard_max_packet_length_ == 0
? max_plaintext_size_
: framer_->GetMaxPlaintextSize(latched_hard_max_packet_length_);
const QuicPacketLength largest_payload =
max_plaintext_size -
std::min(max_plaintext_size, packet_header_size + kQuicFrameTypeSize);
// This must always be less than or equal to GetCurrentLargestMessagePayload.
DCHECK_LE(largest_payload, GetCurrentLargestMessagePayload());
return largest_payload;
}
bool QuicPacketCreator::HasIetfLongHeader() const {
return VersionHasIetfInvariantHeader(framer_->transport_version()) &&
packet_.encryption_level < ENCRYPTION_FORWARD_SECURE;
}
// static
size_t QuicPacketCreator::MinPlaintextPacketSize(
const ParsedQuicVersion& version) {
if (!version.HasHeaderProtection()) {
return 0;
}
// Header protection samples 16 bytes of ciphertext starting 4 bytes after the
// packet number. In IETF QUIC, all AEAD algorithms have a 16-byte auth tag
// (i.e. the ciphertext is 16 bytes larger than the plaintext). Since packet
// numbers could be as small as 1 byte, but the sample starts 4 bytes after
// the packet number, at least 3 bytes of plaintext are needed to make sure
// that there is enough ciphertext to sample.
//
// Google QUIC crypto uses different AEAD algorithms - in particular the auth
// tags are only 12 bytes instead of 16 bytes. Since the auth tag is 4 bytes
// shorter, 4 more bytes of plaintext are needed to guarantee there is enough
// ciphertext to sample.
//
// This method could check for PROTOCOL_TLS1_3 vs PROTOCOL_QUIC_CRYPTO and
// return 3 when TLS 1.3 is in use (the use of IETF vs Google QUIC crypters is
// determined based on the handshake protocol used). However, even when TLS
// 1.3 is used, unittests still use NullEncrypter/NullDecrypter (and other
// test crypters) which also only use 12 byte tags.
//
// TODO(nharper): Set this based on the handshake protocol in use.
return 7;
}
QuicPacketNumber QuicPacketCreator::NextSendingPacketNumber() const {
if (!packet_number().IsInitialized()) {
return framer_->first_sending_packet_number();
}
return packet_number() + 1;
}
bool QuicPacketCreator::PacketFlusherAttached() const {
DCHECK(combine_generator_and_creator_);
return flusher_attached_;
}
#undef ENDPOINT // undef for jumbo builds
} // namespace quic