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quiche / quiche / d072d377880775526b42f4b2ec9c6c4e995adb4f / . / quic / core / quic_dispatcher.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 "quic/core/quic_dispatcher.h"
#include <memory>
#include <string>
#include <utility>
#include "absl/container/flat_hash_set.h"
#include "absl/strings/string_view.h"
#include "quic/core/chlo_extractor.h"
#include "quic/core/crypto/crypto_protocol.h"
#include "quic/core/crypto/quic_random.h"
#include "quic/core/quic_connection_id.h"
#include "quic/core/quic_error_codes.h"
#include "quic/core/quic_session.h"
#include "quic/core/quic_time_wait_list_manager.h"
#include "quic/core/quic_types.h"
#include "quic/core/quic_utils.h"
#include "quic/core/quic_versions.h"
#include "quic/core/tls_chlo_extractor.h"
#include "quic/platform/api/quic_bug_tracker.h"
#include "quic/platform/api/quic_flag_utils.h"
#include "quic/platform/api/quic_flags.h"
#include "quic/platform/api/quic_logging.h"
#include "quic/platform/api/quic_stack_trace.h"
#include "common/quiche_text_utils.h"
namespace quic {
using BufferedPacket = QuicBufferedPacketStore::BufferedPacket;
using BufferedPacketList = QuicBufferedPacketStore::BufferedPacketList;
using EnqueuePacketResult = QuicBufferedPacketStore::EnqueuePacketResult;
namespace {
// Minimal INITIAL packet length sent by clients is 1200.
const QuicPacketLength kMinClientInitialPacketLength = 1200;
// An alarm that informs the QuicDispatcher to delete old sessions.
class DeleteSessionsAlarm : public QuicAlarm::DelegateWithoutContext {
public:
explicit DeleteSessionsAlarm(QuicDispatcher* dispatcher)
: dispatcher_(dispatcher) {}
DeleteSessionsAlarm(const DeleteSessionsAlarm&) = delete;
DeleteSessionsAlarm& operator=(const DeleteSessionsAlarm&) = delete;
void OnAlarm() override { dispatcher_->DeleteSessions(); }
private:
// Not owned.
QuicDispatcher* dispatcher_;
};
// An alarm that informs the QuicDispatcher to clear
// recent_stateless_reset_addresses_.
class ClearStatelessResetAddressesAlarm
: public QuicAlarm::DelegateWithoutContext {
public:
explicit ClearStatelessResetAddressesAlarm(QuicDispatcher* dispatcher)
: dispatcher_(dispatcher) {}
ClearStatelessResetAddressesAlarm(const DeleteSessionsAlarm&) = delete;
ClearStatelessResetAddressesAlarm& operator=(const DeleteSessionsAlarm&) =
delete;
void OnAlarm() override { dispatcher_->ClearStatelessResetAddresses(); }
private:
// Not owned.
QuicDispatcher* dispatcher_;
};
// Collects packets serialized by a QuicPacketCreator in order
// to be handed off to the time wait list manager.
class PacketCollector : public QuicPacketCreator::DelegateInterface,
public QuicStreamFrameDataProducer {
public:
explicit PacketCollector(QuicBufferAllocator* allocator)
: send_buffer_(allocator) {}
~PacketCollector() override = default;
// QuicPacketCreator::DelegateInterface methods:
void OnSerializedPacket(SerializedPacket serialized_packet) override {
// Make a copy of the serialized packet to send later.
packets_.emplace_back(
new QuicEncryptedPacket(CopyBuffer(serialized_packet),
serialized_packet.encrypted_length, true));
}
QuicPacketBuffer GetPacketBuffer() override {
// Let QuicPacketCreator to serialize packets on stack buffer.
return {nullptr, nullptr};
}
void OnUnrecoverableError(QuicErrorCode /*error*/,
const std::string& /*error_details*/) override {}
bool ShouldGeneratePacket(HasRetransmittableData /*retransmittable*/,
IsHandshake /*handshake*/) override {
QUICHE_DCHECK(false);
return true;
}
const QuicFrames MaybeBundleAckOpportunistically() override {
QUICHE_DCHECK(false);
return {};
}
SerializedPacketFate GetSerializedPacketFate(
bool /*is_mtu_discovery*/,
EncryptionLevel /*encryption_level*/) override {
return SEND_TO_WRITER;
}
// QuicStreamFrameDataProducer
WriteStreamDataResult WriteStreamData(QuicStreamId /*id*/,
QuicStreamOffset offset,
QuicByteCount data_length,
QuicDataWriter* writer) override {
if (send_buffer_.WriteStreamData(offset, data_length, writer)) {
return WRITE_SUCCESS;
}
return WRITE_FAILED;
}
bool WriteCryptoData(EncryptionLevel /*level*/,
QuicStreamOffset offset,
QuicByteCount data_length,
QuicDataWriter* writer) override {
return send_buffer_.WriteStreamData(offset, data_length, writer);
}
std::vector<std::unique_ptr<QuicEncryptedPacket>>* packets() {
return &packets_;
}
private:
std::vector<std::unique_ptr<QuicEncryptedPacket>> packets_;
// This is only needed until the packets are encrypted. Once packets are
// encrypted, the stream data is no longer required.
QuicStreamSendBuffer send_buffer_;
};
// Helper for statelessly closing connections by generating the
// correct termination packets and adding the connection to the time wait
// list manager.
class StatelessConnectionTerminator {
public:
StatelessConnectionTerminator(QuicConnectionId server_connection_id,
const ParsedQuicVersion version,
QuicConnectionHelperInterface* helper,
QuicTimeWaitListManager* time_wait_list_manager)
: server_connection_id_(server_connection_id),
framer_(ParsedQuicVersionVector{version},
/*unused*/ QuicTime::Zero(),
Perspective::IS_SERVER,
/*unused*/ kQuicDefaultConnectionIdLength),
collector_(helper->GetStreamSendBufferAllocator()),
creator_(server_connection_id, &framer_, &collector_),
time_wait_list_manager_(time_wait_list_manager) {
framer_.set_data_producer(&collector_);
framer_.SetInitialObfuscators(server_connection_id);
}
~StatelessConnectionTerminator() {
// Clear framer's producer.
framer_.set_data_producer(nullptr);
}
// Generates a packet containing a CONNECTION_CLOSE frame specifying
// |error_code| and |error_details| and add the connection to time wait.
void CloseConnection(QuicErrorCode error_code,
const std::string& error_details,
bool ietf_quic,
std::vector<QuicConnectionId> active_connection_ids) {
SerializeConnectionClosePacket(error_code, error_details);
time_wait_list_manager_->AddConnectionIdToTimeWait(
QuicTimeWaitListManager::SEND_TERMINATION_PACKETS,
TimeWaitConnectionInfo(ietf_quic, collector_.packets(),
std::move(active_connection_ids),
/*srtt=*/QuicTime::Delta::Zero()));
}
private:
void SerializeConnectionClosePacket(QuicErrorCode error_code,
const std::string& error_details) {
QuicConnectionCloseFrame* frame =
new QuicConnectionCloseFrame(framer_.transport_version(), error_code,
NO_IETF_QUIC_ERROR, error_details,
/*transport_close_frame_type=*/0);
if (!creator_.AddFrame(QuicFrame(frame), NOT_RETRANSMISSION)) {
QUIC_BUG(quic_bug_10287_1) << "Unable to add frame to an empty packet";
delete frame;
return;
}
creator_.FlushCurrentPacket();
QUICHE_DCHECK_EQ(1u, collector_.packets()->size());
}
QuicConnectionId server_connection_id_;
QuicFramer framer_;
// Set as the visitor of |creator_| to collect any generated packets.
PacketCollector collector_;
QuicPacketCreator creator_;
QuicTimeWaitListManager* time_wait_list_manager_;
};
// Class which extracts the ALPN and SNI from a QUIC_CRYPTO CHLO packet.
class ChloAlpnSniExtractor : public ChloExtractor::Delegate {
public:
void OnChlo(QuicTransportVersion version,
QuicConnectionId /*server_connection_id*/,
const CryptoHandshakeMessage& chlo) override {
absl::string_view alpn_value;
if (chlo.GetStringPiece(kALPN, &alpn_value)) {
alpn_ = std::string(alpn_value);
}
absl::string_view sni;
if (chlo.GetStringPiece(quic::kSNI, &sni)) {
sni_ = std::string(sni);
}
absl::string_view uaid_value;
if (chlo.GetStringPiece(quic::kUAID, &uaid_value)) {
uaid_ = std::string(uaid_value);
}
if (version == LegacyVersionForEncapsulation().transport_version) {
absl::string_view qlve_value;
if (chlo.GetStringPiece(kQLVE, &qlve_value)) {
legacy_version_encapsulation_inner_packet_ = std::string(qlve_value);
}
}
}
std::string&& ConsumeAlpn() { return std::move(alpn_); }
std::string&& ConsumeSni() { return std::move(sni_); }
std::string&& ConsumeUaid() { return std::move(uaid_); }
std::string&& ConsumeLegacyVersionEncapsulationInnerPacket() {
return std::move(legacy_version_encapsulation_inner_packet_);
}
private:
std::string alpn_;
std::string sni_;
std::string uaid_;
std::string legacy_version_encapsulation_inner_packet_;
};
bool MaybeHandleLegacyVersionEncapsulation(
QuicDispatcher* dispatcher,
std::string legacy_version_encapsulation_inner_packet,
const ReceivedPacketInfo& packet_info) {
if (legacy_version_encapsulation_inner_packet.empty()) {
// This CHLO did not contain the Legacy Version Encapsulation tag.
return false;
}
PacketHeaderFormat format;
QuicLongHeaderType long_packet_type;
bool version_present;
bool has_length_prefix;
QuicVersionLabel version_label;
ParsedQuicVersion parsed_version = ParsedQuicVersion::Unsupported();
QuicConnectionId destination_connection_id, source_connection_id;
absl::optional<absl::string_view> retry_token;
std::string detailed_error;
const QuicErrorCode error = QuicFramer::ParsePublicHeaderDispatcher(
QuicEncryptedPacket(legacy_version_encapsulation_inner_packet.data(),
legacy_version_encapsulation_inner_packet.length()),
kQuicDefaultConnectionIdLength, &format, &long_packet_type,
&version_present, &has_length_prefix, &version_label, &parsed_version,
&destination_connection_id, &source_connection_id, &retry_token,
&detailed_error);
if (error != QUIC_NO_ERROR) {
QUIC_DLOG(ERROR)
<< "Failed to parse Legacy Version Encapsulation inner packet:"
<< detailed_error;
return false;
}
if (destination_connection_id != packet_info.destination_connection_id) {
// We enforce that the inner and outer connection IDs match to make sure
// this never impacts routing of packets.
QUIC_DLOG(ERROR) << "Ignoring Legacy Version Encapsulation packet "
"with mismatched connection ID "
<< destination_connection_id << " vs "
<< packet_info.destination_connection_id;
return false;
}
if (legacy_version_encapsulation_inner_packet.length() >=
packet_info.packet.length()) {
QUIC_BUG(quic_bug_10287_2)
<< "Inner packet cannot be larger than outer "
<< legacy_version_encapsulation_inner_packet.length() << " vs "
<< packet_info.packet.length();
return false;
}
QUIC_DVLOG(1) << "Extracted a Legacy Version Encapsulation "
<< legacy_version_encapsulation_inner_packet.length()
<< " byte packet of version " << parsed_version;
// Append zeroes to the end of the packet. This will ensure that
// we use the right number of bytes for calculating anti-amplification
// limits. Note that this only works for long headers of versions that carry
// long header lengths, since they'll ignore any trailing zeroes. We still
// do this for all packets to ensure version negotiation works.
legacy_version_encapsulation_inner_packet.append(
packet_info.packet.length() -
legacy_version_encapsulation_inner_packet.length(),
0x00);
// Process the inner packet as if it had been received by itself.
QuicReceivedPacket received_encapsulated_packet(
legacy_version_encapsulation_inner_packet.data(),
legacy_version_encapsulation_inner_packet.length(),
packet_info.packet.receipt_time());
dispatcher->ProcessPacket(packet_info.self_address, packet_info.peer_address,
received_encapsulated_packet);
QUIC_CODE_COUNT(quic_legacy_version_encapsulation_decapsulated);
return true;
}
} // namespace
QuicDispatcher::QuicDispatcher(
const QuicConfig* config, const QuicCryptoServerConfig* crypto_config,
QuicVersionManager* version_manager,
std::unique_ptr<QuicConnectionHelperInterface> helper,
std::unique_ptr<QuicCryptoServerStreamBase::Helper> session_helper,
std::unique_ptr<QuicAlarmFactory> alarm_factory,
uint8_t expected_server_connection_id_length)
: config_(config),
crypto_config_(crypto_config),
compressed_certs_cache_(
QuicCompressedCertsCache::kQuicCompressedCertsCacheSize),
helper_(std::move(helper)),
session_helper_(std::move(session_helper)),
alarm_factory_(std::move(alarm_factory)),
delete_sessions_alarm_(
alarm_factory_->CreateAlarm(new DeleteSessionsAlarm(this))),
buffered_packets_(this, helper_->GetClock(), alarm_factory_.get()),
version_manager_(version_manager),
last_error_(QUIC_NO_ERROR),
new_sessions_allowed_per_event_loop_(0u),
accept_new_connections_(true),
allow_short_initial_server_connection_ids_(false),
expected_server_connection_id_length_(
expected_server_connection_id_length),
clear_stateless_reset_addresses_alarm_(alarm_factory_->CreateAlarm(
new ClearStatelessResetAddressesAlarm(this))),
should_update_expected_server_connection_id_length_(false) {
QUIC_BUG_IF(quic_bug_12724_1, GetSupportedVersions().empty())
<< "Trying to create dispatcher without any supported versions";
QUIC_DLOG(INFO) << "Created QuicDispatcher with versions: "
<< ParsedQuicVersionVectorToString(GetSupportedVersions());
}
QuicDispatcher::~QuicDispatcher() {
if (delete_sessions_alarm_ != nullptr) {
delete_sessions_alarm_->PermanentCancel();
}
if (clear_stateless_reset_addresses_alarm_ != nullptr) {
clear_stateless_reset_addresses_alarm_->PermanentCancel();
}
reference_counted_session_map_.clear();
closed_session_list_.clear();
num_sessions_in_session_map_ = 0;
}
void QuicDispatcher::InitializeWithWriter(QuicPacketWriter* writer) {
QUICHE_DCHECK(writer_ == nullptr);
writer_.reset(writer);
time_wait_list_manager_.reset(CreateQuicTimeWaitListManager());
}
void QuicDispatcher::ProcessPacket(const QuicSocketAddress& self_address,
const QuicSocketAddress& peer_address,
const QuicReceivedPacket& packet) {
QUIC_DVLOG(2) << "Dispatcher received encrypted " << packet.length()
<< " bytes:" << std::endl
<< quiche::QuicheTextUtils::HexDump(
absl::string_view(packet.data(), packet.length()));
ReceivedPacketInfo packet_info(self_address, peer_address, packet);
std::string detailed_error;
const QuicErrorCode error = QuicFramer::ParsePublicHeaderDispatcher(
packet, expected_server_connection_id_length_, &packet_info.form,
&packet_info.long_packet_type, &packet_info.version_flag,
&packet_info.use_length_prefix, &packet_info.version_label,
&packet_info.version, &packet_info.destination_connection_id,
&packet_info.source_connection_id, &packet_info.retry_token,
&detailed_error);
if (error != QUIC_NO_ERROR) {
// Packet has framing error.
SetLastError(error);
QUIC_DLOG(ERROR) << detailed_error;
return;
}
if (packet_info.destination_connection_id.length() !=
expected_server_connection_id_length_ &&
!should_update_expected_server_connection_id_length_ &&
packet_info.version.IsKnown() &&
!packet_info.version.AllowsVariableLengthConnectionIds()) {
SetLastError(QUIC_INVALID_PACKET_HEADER);
QUIC_DLOG(ERROR) << "Invalid Connection Id Length";
return;
}
if (packet_info.version_flag && IsSupportedVersion(packet_info.version)) {
if (!QuicUtils::IsConnectionIdValidForVersion(
packet_info.destination_connection_id,
packet_info.version.transport_version)) {
SetLastError(QUIC_INVALID_PACKET_HEADER);
QUIC_DLOG(ERROR)
<< "Invalid destination connection ID length for version";
return;
}
if (packet_info.version.SupportsClientConnectionIds() &&
!QuicUtils::IsConnectionIdValidForVersion(
packet_info.source_connection_id,
packet_info.version.transport_version)) {
SetLastError(QUIC_INVALID_PACKET_HEADER);
QUIC_DLOG(ERROR) << "Invalid source connection ID length for version";
return;
}
}
if (should_update_expected_server_connection_id_length_) {
expected_server_connection_id_length_ =
packet_info.destination_connection_id.length();
}
if (MaybeDispatchPacket(packet_info)) {
// Packet has been dropped or successfully dispatched, stop processing.
return;
}
ProcessHeader(&packet_info);
}
QuicConnectionId QuicDispatcher::MaybeReplaceServerConnectionId(
const QuicConnectionId& server_connection_id,
const ParsedQuicVersion& version) const {
const uint8_t server_connection_id_length = server_connection_id.length();
if (server_connection_id_length == expected_server_connection_id_length_) {
return server_connection_id;
}
QUICHE_DCHECK(version.AllowsVariableLengthConnectionIds());
QuicConnectionId new_connection_id;
if (server_connection_id_length < expected_server_connection_id_length_) {
new_connection_id = ReplaceShortServerConnectionId(
version, server_connection_id, expected_server_connection_id_length_);
// Verify that ReplaceShortServerConnectionId is deterministic.
QUICHE_DCHECK_EQ(
new_connection_id,
ReplaceShortServerConnectionId(version, server_connection_id,
expected_server_connection_id_length_));
} else {
new_connection_id = ReplaceLongServerConnectionId(
version, server_connection_id, expected_server_connection_id_length_);
// Verify that ReplaceLongServerConnectionId is deterministic.
QUICHE_DCHECK_EQ(
new_connection_id,
ReplaceLongServerConnectionId(version, server_connection_id,
expected_server_connection_id_length_));
}
QUICHE_DCHECK_EQ(expected_server_connection_id_length_,
new_connection_id.length());
QUIC_DLOG(INFO) << "Replacing incoming connection ID " << server_connection_id
<< " with " << new_connection_id;
return new_connection_id;
}
QuicConnectionId QuicDispatcher::ReplaceShortServerConnectionId(
const ParsedQuicVersion& /*version*/,
const QuicConnectionId& server_connection_id,
uint8_t expected_server_connection_id_length) const {
QUICHE_DCHECK_LT(server_connection_id.length(),
expected_server_connection_id_length);
return QuicUtils::CreateReplacementConnectionId(
server_connection_id, expected_server_connection_id_length);
}
QuicConnectionId QuicDispatcher::ReplaceLongServerConnectionId(
const ParsedQuicVersion& /*version*/,
const QuicConnectionId& server_connection_id,
uint8_t expected_server_connection_id_length) const {
QUICHE_DCHECK_GT(server_connection_id.length(),
expected_server_connection_id_length);
return QuicUtils::CreateReplacementConnectionId(
server_connection_id, expected_server_connection_id_length);
}
namespace {
constexpr bool IsSourceUdpPortBlocked(uint16_t port) {
// These UDP source ports have been observed in large scale denial of service
// attacks and are not expected to ever carry user traffic, they are therefore
// blocked as a safety measure. See draft-ietf-quic-applicability for details.
constexpr uint16_t blocked_ports[] = {
0, // We cannot send to port 0 so drop that source port.
17, // Quote of the Day, can loop with QUIC.
19, // Chargen, can loop with QUIC.
53, // DNS, vulnerable to reflection attacks.
111, // Portmap.
123, // NTP, vulnerable to reflection attacks.
137, // NETBIOS Name Service,
128, // NETBIOS Datagram Service
161, // SNMP.
389, // CLDAP.
500, // IKE, can loop with QUIC.
1900, // SSDP, vulnerable to reflection attacks.
5353, // mDNS, vulnerable to reflection attacks.
11211, // memcache, vulnerable to reflection attacks.
// This list MUST be sorted in increasing order.
};
constexpr size_t num_blocked_ports = ABSL_ARRAYSIZE(blocked_ports);
constexpr uint16_t highest_blocked_port =
blocked_ports[num_blocked_ports - 1];
if (QUICHE_PREDICT_TRUE(port > highest_blocked_port)) {
// Early-return to skip comparisons for the majority of traffic.
return false;
}
for (size_t i = 0; i < num_blocked_ports; i++) {
if (port == blocked_ports[i]) {
return true;
}
}
return false;
}
} // namespace
bool QuicDispatcher::MaybeDispatchPacket(
const ReceivedPacketInfo& packet_info) {
if (IsSourceUdpPortBlocked(packet_info.peer_address.port())) {
// Silently drop the received packet.
QUIC_CODE_COUNT(quic_dropped_blocked_port);
return true;
}
QuicConnectionId server_connection_id = packet_info.destination_connection_id;
// The IETF spec requires the client to generate an initial server
// connection ID that is at least 64 bits long. After that initial
// connection ID, the dispatcher picks a new one of its expected length.
// Therefore we should never receive a connection ID that is smaller
// than 64 bits and smaller than what we expect. Unless the version is
// unknown, in which case we allow short connection IDs for version
// negotiation because that version could allow those.
if (packet_info.version_flag && packet_info.version.IsKnown() &&
server_connection_id.length() < kQuicMinimumInitialConnectionIdLength &&
server_connection_id.length() < expected_server_connection_id_length_ &&
!allow_short_initial_server_connection_ids_) {
QUICHE_DCHECK(packet_info.version_flag);
QUICHE_DCHECK(packet_info.version.AllowsVariableLengthConnectionIds());
QUIC_DLOG(INFO) << "Packet with short destination connection ID "
<< server_connection_id << " expected "
<< static_cast<int>(expected_server_connection_id_length_);
// Drop the packet silently.
QUIC_CODE_COUNT(quic_dropped_invalid_small_initial_connection_id);
return true;
}
if (packet_info.version_flag && packet_info.version.IsKnown() &&
!QuicUtils::IsConnectionIdLengthValidForVersion(
server_connection_id.length(),
packet_info.version.transport_version)) {
QUIC_DLOG(INFO) << "Packet with destination connection ID "
<< server_connection_id << " is invalid with version "
<< packet_info.version;
// Drop the packet silently.
QUIC_CODE_COUNT(quic_dropped_invalid_initial_connection_id);
return true;
}
// Packets with connection IDs for active connections are processed
// immediately.
auto it = reference_counted_session_map_.find(server_connection_id);
if (it != reference_counted_session_map_.end()) {
QUICHE_DCHECK(!buffered_packets_.HasBufferedPackets(server_connection_id));
if (packet_info.version_flag &&
packet_info.version != it->second->version() &&
packet_info.version == LegacyVersionForEncapsulation()) {
// This packet is using the Legacy Version Encapsulation version but the
// corresponding session isn't, attempt extraction of inner packet.
ChloAlpnSniExtractor alpn_extractor;
if (ChloExtractor::Extract(packet_info.packet, packet_info.version,
config_->create_session_tag_indicators(),
&alpn_extractor,
server_connection_id.length())) {
if (MaybeHandleLegacyVersionEncapsulation(
this,
alpn_extractor.ConsumeLegacyVersionEncapsulationInnerPacket(),
packet_info)) {
return true;
}
}
}
it->second->ProcessUdpPacket(packet_info.self_address,
packet_info.peer_address, packet_info.packet);
return true;
}
if (packet_info.version.IsKnown()) {
// We did not find the connection ID, check if we've replaced it.
// This is only performed for supported versions because packets with
// unsupported versions can flow through this function in order to send
// a version negotiation packet, but we know that their connection ID
// did not get replaced since that is performed on connection creation,
// and that only happens for known verions.
QuicConnectionId replaced_connection_id = MaybeReplaceServerConnectionId(
server_connection_id, packet_info.version);
if (replaced_connection_id != server_connection_id) {
// Search for the replacement.
auto it2 = reference_counted_session_map_.find(replaced_connection_id);
if (it2 != reference_counted_session_map_.end()) {
QUICHE_DCHECK(
!buffered_packets_.HasBufferedPackets(replaced_connection_id));
it2->second->ProcessUdpPacket(packet_info.self_address,
packet_info.peer_address,
packet_info.packet);
return true;
}
}
}
if (buffered_packets_.HasChloForConnection(server_connection_id)) {
BufferEarlyPacket(packet_info);
return true;
}
if (OnFailedToDispatchPacket(packet_info)) {
return true;
}
if (time_wait_list_manager_->IsConnectionIdInTimeWait(server_connection_id)) {
// This connection ID is already in time-wait state.
time_wait_list_manager_->ProcessPacket(
packet_info.self_address, packet_info.peer_address,
packet_info.destination_connection_id, packet_info.form,
packet_info.packet.length(), GetPerPacketContext());
return true;
}
// The packet has an unknown connection ID.
if (!accept_new_connections_ && packet_info.version_flag) {
// If not accepting new connections, reject packets with version which can
// potentially result in new connection creation. But if the packet doesn't
// have version flag, leave it to ValidityChecks() to reset it.
// By adding the connection to time wait list, following packets on this
// connection will not reach ShouldAcceptNewConnections().
StatelesslyTerminateConnection(
packet_info.destination_connection_id, packet_info.form,
packet_info.version_flag, packet_info.use_length_prefix,
packet_info.version, QUIC_HANDSHAKE_FAILED,
"Stop accepting new connections",
quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
// Time wait list will reject the packet correspondingly..
time_wait_list_manager()->ProcessPacket(
packet_info.self_address, packet_info.peer_address,
packet_info.destination_connection_id, packet_info.form,
packet_info.packet.length(), GetPerPacketContext());
OnNewConnectionRejected();
return true;
}
// Unless the packet provides a version, assume that we can continue
// processing using our preferred version.
if (packet_info.version_flag) {
if (!IsSupportedVersion(packet_info.version)) {
if (ShouldCreateSessionForUnknownVersion(packet_info.version_label)) {
return false;
}
if (!crypto_config()->validate_chlo_size() ||
packet_info.packet.length() >= kMinPacketSizeForVersionNegotiation) {
// Since the version is not supported, send a version negotiation
// packet and stop processing the current packet.
QuicConnectionId client_connection_id =
packet_info.source_connection_id;
time_wait_list_manager()->SendVersionNegotiationPacket(
server_connection_id, client_connection_id,
packet_info.form != GOOGLE_QUIC_PACKET,
packet_info.use_length_prefix, GetSupportedVersions(),
packet_info.self_address, packet_info.peer_address,
GetPerPacketContext());
}
return true;
}
if (crypto_config()->validate_chlo_size() &&
packet_info.form == IETF_QUIC_LONG_HEADER_PACKET &&
packet_info.long_packet_type == INITIAL &&
packet_info.packet.length() < kMinClientInitialPacketLength) {
QUIC_DVLOG(1) << "Dropping initial packet which is too short, length: "
<< packet_info.packet.length();
QUIC_CODE_COUNT(quic_drop_small_initial_packets);
return true;
}
}
return false;
}
void QuicDispatcher::ProcessHeader(ReceivedPacketInfo* packet_info) {
QuicConnectionId server_connection_id =
packet_info->destination_connection_id;
// Packet's connection ID is unknown. Apply the validity checks.
QuicPacketFate fate = ValidityChecks(*packet_info);
if (fate == kFateProcess) {
absl::optional<ParsedClientHello> parsed_chlo =
TryExtractChloOrBufferEarlyPacket(*packet_info);
if (!parsed_chlo.has_value()) {
// Client Hello incomplete. Packet has been buffered or (rarely) dropped.
return;
}
// Client Hello fully received.
fate = ValidityChecksOnFullChlo(*packet_info, *parsed_chlo);
if (fate == kFateProcess) {
QUICHE_DCHECK(
parsed_chlo->legacy_version_encapsulation_inner_packet.empty() ||
!packet_info->version.UsesTls());
if (MaybeHandleLegacyVersionEncapsulation(
this, parsed_chlo->legacy_version_encapsulation_inner_packet,
*packet_info)) {
return;
}
ProcessChlo(*std::move(parsed_chlo), packet_info);
return;
}
}
switch (fate) {
case kFateProcess:
// kFateProcess have been processed above.
QUIC_BUG(quic_dispatcher_bad_packet_fate) << fate;
break;
case kFateTimeWait:
// Add this connection_id to the time-wait state, to safely reject
// future packets.
QUIC_DLOG(INFO) << "Adding connection ID " << server_connection_id
<< " to time-wait list.";
QUIC_CODE_COUNT(quic_reject_fate_time_wait);
StatelesslyTerminateConnection(
server_connection_id, packet_info->form, packet_info->version_flag,
packet_info->use_length_prefix, packet_info->version,
QUIC_HANDSHAKE_FAILED, "Reject connection",
quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
QUICHE_DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
server_connection_id));
time_wait_list_manager_->ProcessPacket(
packet_info->self_address, packet_info->peer_address,
server_connection_id, packet_info->form, packet_info->packet.length(),
GetPerPacketContext());
buffered_packets_.DiscardPackets(server_connection_id);
break;
case kFateDrop:
break;
}
}
absl::optional<ParsedClientHello>
QuicDispatcher::TryExtractChloOrBufferEarlyPacket(
const ReceivedPacketInfo& packet_info) {
if (packet_info.version.UsesTls()) {
bool has_full_tls_chlo = false;
std::string sni;
std::vector<std::string> alpns;
bool resumption_attempted = false, early_data_attempted = false;
if (buffered_packets_.HasBufferedPackets(
packet_info.destination_connection_id)) {
// If we already have buffered packets for this connection ID,
// use the associated TlsChloExtractor to parse this packet.
has_full_tls_chlo = buffered_packets_.IngestPacketForTlsChloExtraction(
packet_info.destination_connection_id, packet_info.version,
packet_info.packet, &alpns, &sni, &resumption_attempted,
&early_data_attempted);
} else {
// If we do not have a BufferedPacketList for this connection ID,
// create a single-use one to check whether this packet contains a
// full single-packet CHLO.
TlsChloExtractor tls_chlo_extractor;
tls_chlo_extractor.IngestPacket(packet_info.version, packet_info.packet);
if (tls_chlo_extractor.HasParsedFullChlo()) {
// This packet contains a full single-packet CHLO.
has_full_tls_chlo = true;
alpns = tls_chlo_extractor.alpns();
sni = tls_chlo_extractor.server_name();
resumption_attempted = tls_chlo_extractor.resumption_attempted();
early_data_attempted = tls_chlo_extractor.early_data_attempted();
}
}
if (!has_full_tls_chlo) {
// This packet does not contain a full CHLO. It could be a 0-RTT
// packet that arrived before the CHLO (due to loss or reordering),
// or it could be a fragment of a multi-packet CHLO.
BufferEarlyPacket(packet_info);
return absl::nullopt;
}
ParsedClientHello parsed_chlo;
parsed_chlo.sni = std::move(sni);
parsed_chlo.alpns = std::move(alpns);
if (packet_info.retry_token.has_value()) {
parsed_chlo.retry_token = std::string(*packet_info.retry_token);
}
parsed_chlo.resumption_attempted = resumption_attempted;
parsed_chlo.early_data_attempted = early_data_attempted;
return parsed_chlo;
}
ChloAlpnSniExtractor alpn_extractor;
if (GetQuicFlag(FLAGS_quic_allow_chlo_buffering) &&
!ChloExtractor::Extract(packet_info.packet, packet_info.version,
config_->create_session_tag_indicators(),
&alpn_extractor,
packet_info.destination_connection_id.length())) {
// Buffer non-CHLO packets.
BufferEarlyPacket(packet_info);
return absl::nullopt;
}
// We only apply this check for versions that do not use the IETF
// invariant header because those versions are already checked in
// QuicDispatcher::MaybeDispatchPacket.
if (packet_info.version_flag &&
!packet_info.version.HasIetfInvariantHeader() &&
crypto_config()->validate_chlo_size() &&
packet_info.packet.length() < kMinClientInitialPacketLength) {
QUIC_DVLOG(1) << "Dropping CHLO packet which is too short, length: "
<< packet_info.packet.length();
QUIC_CODE_COUNT(quic_drop_small_chlo_packets);
return absl::nullopt;
}
ParsedClientHello parsed_chlo;
parsed_chlo.legacy_version_encapsulation_inner_packet =
alpn_extractor.ConsumeLegacyVersionEncapsulationInnerPacket();
parsed_chlo.sni = alpn_extractor.ConsumeSni();
parsed_chlo.uaid = alpn_extractor.ConsumeUaid();
parsed_chlo.alpns = {alpn_extractor.ConsumeAlpn()};
return parsed_chlo;
}
std::string QuicDispatcher::SelectAlpn(const std::vector<std::string>& alpns) {
if (alpns.empty()) {
return "";
}
if (alpns.size() > 1u) {
const std::vector<std::string>& supported_alpns =
version_manager_->GetSupportedAlpns();
for (const std::string& alpn : alpns) {
if (std::find(supported_alpns.begin(), supported_alpns.end(), alpn) !=
supported_alpns.end()) {
return alpn;
}
}
}
return alpns[0];
}
QuicDispatcher::QuicPacketFate QuicDispatcher::ValidityChecks(
const ReceivedPacketInfo& packet_info) {
if (!packet_info.version_flag) {
QUIC_DLOG(INFO)
<< "Packet without version arrived for unknown connection ID "
<< packet_info.destination_connection_id;
MaybeResetPacketsWithNoVersion(packet_info);
return kFateDrop;
}
// Let the connection parse and validate packet number.
return kFateProcess;
}
void QuicDispatcher::CleanUpSession(QuicConnectionId server_connection_id,
QuicConnection* connection,
QuicErrorCode /*error*/,
const std::string& /*error_details*/,
ConnectionCloseSource /*source*/) {
write_blocked_list_.erase(connection);
QuicTimeWaitListManager::TimeWaitAction action =
QuicTimeWaitListManager::SEND_STATELESS_RESET;
if (connection->termination_packets() != nullptr &&
!connection->termination_packets()->empty()) {
action = QuicTimeWaitListManager::SEND_CONNECTION_CLOSE_PACKETS;
} else {
if (!connection->IsHandshakeComplete()) {
// TODO(fayang): Do not serialize connection close packet if the
// connection is closed by the client.
if (!connection->version().HasIetfInvariantHeader()) {
QUIC_CODE_COUNT(gquic_add_to_time_wait_list_with_handshake_failed);
} else {
QUIC_CODE_COUNT(quic_v44_add_to_time_wait_list_with_handshake_failed);
}
// This serializes a connection close termination packet and adds the
// connection to the time wait list.
StatelessConnectionTerminator terminator(
server_connection_id, connection->version(), helper_.get(),
time_wait_list_manager_.get());
terminator.CloseConnection(
QUIC_HANDSHAKE_FAILED,
"Connection is closed by server before handshake confirmed",
connection->version().HasIetfInvariantHeader(),
connection->GetActiveServerConnectionIds());
return;
}
QUIC_CODE_COUNT(quic_v44_add_to_time_wait_list_with_stateless_reset);
}
time_wait_list_manager_->AddConnectionIdToTimeWait(
action,
TimeWaitConnectionInfo(
connection->version().HasIetfInvariantHeader(),
connection->termination_packets(),
connection->GetActiveServerConnectionIds(),
connection->sent_packet_manager().GetRttStats()->smoothed_rtt()));
}
void QuicDispatcher::StartAcceptingNewConnections() {
accept_new_connections_ = true;
}
void QuicDispatcher::StopAcceptingNewConnections() {
accept_new_connections_ = false;
// No more CHLO will arrive and buffered CHLOs shouldn't be able to create
// connections.
buffered_packets_.DiscardAllPackets();
}
void QuicDispatcher::PerformActionOnActiveSessions(
std::function<void(QuicSession*)> operation) const {
absl::flat_hash_set<QuicSession*> visited_session;
visited_session.reserve(reference_counted_session_map_.size());
for (auto const& kv : reference_counted_session_map_) {
QuicSession* session = kv.second.get();
if (visited_session.insert(session).second) {
operation(session);
}
}
}
// Get a snapshot of all sessions.
std::vector<std::shared_ptr<QuicSession>> QuicDispatcher::GetSessionsSnapshot()
const {
std::vector<std::shared_ptr<QuicSession>> snapshot;
snapshot.reserve(reference_counted_session_map_.size());
absl::flat_hash_set<QuicSession*> visited_session;
visited_session.reserve(reference_counted_session_map_.size());
for (auto const& kv : reference_counted_session_map_) {
QuicSession* session = kv.second.get();
if (visited_session.insert(session).second) {
snapshot.push_back(kv.second);
}
}
return snapshot;
}
std::unique_ptr<QuicPerPacketContext> QuicDispatcher::GetPerPacketContext()
const {
return nullptr;
}
void QuicDispatcher::DeleteSessions() {
if (!write_blocked_list_.empty()) {
for (const auto& session : closed_session_list_) {
if (write_blocked_list_.erase(session->connection()) != 0) {
QUIC_BUG(quic_bug_12724_2)
<< "QuicConnection was in WriteBlockedList before destruction "
<< session->connection()->connection_id();
}
}
}
closed_session_list_.clear();
}
void QuicDispatcher::ClearStatelessResetAddresses() {
recent_stateless_reset_addresses_.clear();
}
void QuicDispatcher::OnCanWrite() {
// The socket is now writable.
writer_->SetWritable();
// Move every blocked writer in |write_blocked_list_| to a temporary list.
const size_t num_blocked_writers_before = write_blocked_list_.size();
WriteBlockedList temp_list;
temp_list.swap(write_blocked_list_);
QUICHE_DCHECK(write_blocked_list_.empty());
// Give each blocked writer a chance to write what they indended to write.
// If they are blocked again, they will call |OnWriteBlocked| to add
// themselves back into |write_blocked_list_|.
while (!temp_list.empty()) {
QuicBlockedWriterInterface* blocked_writer = temp_list.begin()->first;
temp_list.erase(temp_list.begin());
blocked_writer->OnBlockedWriterCanWrite();
}
const size_t num_blocked_writers_after = write_blocked_list_.size();
if (num_blocked_writers_after != 0) {
if (num_blocked_writers_before == num_blocked_writers_after) {
QUIC_CODE_COUNT(quic_zero_progress_on_can_write);
} else {
QUIC_CODE_COUNT(quic_blocked_again_on_can_write);
}
}
}
bool QuicDispatcher::HasPendingWrites() const {
return !write_blocked_list_.empty();
}
void QuicDispatcher::Shutdown() {
while (!reference_counted_session_map_.empty()) {
QuicSession* session = reference_counted_session_map_.begin()->second.get();
session->connection()->CloseConnection(
QUIC_PEER_GOING_AWAY, "Server shutdown imminent",
ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
// Validate that the session removes itself from the session map on close.
QUICHE_DCHECK(reference_counted_session_map_.empty() ||
reference_counted_session_map_.begin()->second.get() !=
session);
}
DeleteSessions();
}
void QuicDispatcher::OnConnectionClosed(QuicConnectionId server_connection_id,
QuicErrorCode error,
const std::string& error_details,
ConnectionCloseSource source) {
auto it = reference_counted_session_map_.find(server_connection_id);
if (it == reference_counted_session_map_.end()) {
QUIC_BUG(quic_bug_10287_3) << "ConnectionId " << server_connection_id
<< " does not exist in the session map. Error: "
<< QuicErrorCodeToString(error);
QUIC_BUG(quic_bug_10287_4) << QuicStackTrace();
return;
}
QUIC_DLOG_IF(INFO, error != QUIC_NO_ERROR)
<< "Closing connection (" << server_connection_id
<< ") due to error: " << QuicErrorCodeToString(error)
<< ", with details: " << error_details;
QuicConnection* connection = it->second->connection();
if (ShouldDestroySessionAsynchronously()) {
// Set up alarm to fire immediately to bring destruction of this session
// out of current call stack.
if (closed_session_list_.empty()) {
delete_sessions_alarm_->Update(helper()->GetClock()->ApproximateNow(),
QuicTime::Delta::Zero());
}
closed_session_list_.push_back(std::move(it->second));
}
CleanUpSession(it->first, connection, error, error_details, source);
for (const QuicConnectionId& cid :
connection->GetActiveServerConnectionIds()) {
reference_counted_session_map_.erase(cid);
}
--num_sessions_in_session_map_;
}
void QuicDispatcher::OnWriteBlocked(
QuicBlockedWriterInterface* blocked_writer) {
if (!blocked_writer->IsWriterBlocked()) {
// It is a programming error if this ever happens. When we are sure it is
// not happening, replace it with a QUICHE_DCHECK.
QUIC_BUG(quic_bug_12724_4)
<< "Tried to add writer into blocked list when it shouldn't be added";
// Return without adding the connection to the blocked list, to avoid
// infinite loops in OnCanWrite.
return;
}
write_blocked_list_.insert(std::make_pair(blocked_writer, true));
}
void QuicDispatcher::OnRstStreamReceived(const QuicRstStreamFrame& /*frame*/) {}
void QuicDispatcher::OnStopSendingReceived(
const QuicStopSendingFrame& /*frame*/) {}
void QuicDispatcher::OnNewConnectionIdSent(
const QuicConnectionId& server_connection_id,
const QuicConnectionId& new_connection_id) {
auto it = reference_counted_session_map_.find(server_connection_id);
if (it == reference_counted_session_map_.end()) {
QUIC_BUG(quic_bug_10287_7)
<< "Couldn't locate the session that issues the connection ID in "
"reference_counted_session_map_. server_connection_id:"
<< server_connection_id << " new_connection_id: " << new_connection_id;
return;
}
// Count new connection ID added to the dispatcher map.
QUIC_RELOADABLE_FLAG_COUNT_N(quic_connection_migration_use_new_cid_v2, 6, 6);
auto insertion_result = reference_counted_session_map_.insert(
std::make_pair(new_connection_id, it->second));
QUICHE_DCHECK(insertion_result.second);
}
void QuicDispatcher::OnConnectionIdRetired(
const QuicConnectionId& server_connection_id) {
reference_counted_session_map_.erase(server_connection_id);
}
void QuicDispatcher::OnConnectionAddedToTimeWaitList(
QuicConnectionId server_connection_id) {
QUIC_DLOG(INFO) << "Connection " << server_connection_id
<< " added to time wait list.";
}
void QuicDispatcher::StatelesslyTerminateConnection(
QuicConnectionId server_connection_id,
PacketHeaderFormat format,
bool version_flag,
bool use_length_prefix,
ParsedQuicVersion version,
QuicErrorCode error_code,
const std::string& error_details,
QuicTimeWaitListManager::TimeWaitAction action) {
if (format != IETF_QUIC_LONG_HEADER_PACKET && !version_flag) {
QUIC_DVLOG(1) << "Statelessly terminating " << server_connection_id
<< " based on a non-ietf-long packet, action:" << action
<< ", error_code:" << error_code
<< ", error_details:" << error_details;
time_wait_list_manager_->AddConnectionIdToTimeWait(
action, TimeWaitConnectionInfo(format != GOOGLE_QUIC_PACKET, nullptr,
{server_connection_id}));
return;
}
// If the version is known and supported by framer, send a connection close.
if (IsSupportedVersion(version)) {
QUIC_DVLOG(1)
<< "Statelessly terminating " << server_connection_id
<< " based on an ietf-long packet, which has a supported version:"
<< version << ", error_code:" << error_code
<< ", error_details:" << error_details;
StatelessConnectionTerminator terminator(server_connection_id, version,
helper_.get(),
time_wait_list_manager_.get());
// This also adds the connection to time wait list.
terminator.CloseConnection(
error_code, error_details, format != GOOGLE_QUIC_PACKET,
/*active_connection_ids=*/{server_connection_id});
QUIC_CODE_COUNT(quic_dispatcher_generated_connection_close);
QuicSession::RecordConnectionCloseAtServer(
error_code, ConnectionCloseSource::FROM_SELF);
return;
}
QUIC_DVLOG(1)
<< "Statelessly terminating " << server_connection_id
<< " based on an ietf-long packet, which has an unsupported version:"
<< version << ", error_code:" << error_code
<< ", error_details:" << error_details;
// Version is unknown or unsupported by framer, send a version negotiation
// with an empty version list, which can be understood by the client.
std::vector<std::unique_ptr<QuicEncryptedPacket>> termination_packets;
termination_packets.push_back(QuicFramer::BuildVersionNegotiationPacket(
server_connection_id, EmptyQuicConnectionId(),
/*ietf_quic=*/format != GOOGLE_QUIC_PACKET, use_length_prefix,
/*versions=*/{}));
time_wait_list_manager()->AddConnectionIdToTimeWait(
QuicTimeWaitListManager::SEND_TERMINATION_PACKETS,
TimeWaitConnectionInfo(/*ietf_quic=*/format != GOOGLE_QUIC_PACKET,
&termination_packets, {server_connection_id}));
}
bool QuicDispatcher::ShouldCreateSessionForUnknownVersion(
QuicVersionLabel /*version_label*/) {
return false;
}
void QuicDispatcher::OnExpiredPackets(
QuicConnectionId server_connection_id,
BufferedPacketList early_arrived_packets) {
QUIC_CODE_COUNT(quic_reject_buffered_packets_expired);
StatelesslyTerminateConnection(
server_connection_id,
early_arrived_packets.ietf_quic ? IETF_QUIC_LONG_HEADER_PACKET
: GOOGLE_QUIC_PACKET,
/*version_flag=*/true,
early_arrived_packets.version.HasLengthPrefixedConnectionIds(),
early_arrived_packets.version, QUIC_HANDSHAKE_FAILED,
"Packets buffered for too long",
quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
}
void QuicDispatcher::ProcessBufferedChlos(size_t max_connections_to_create) {
// Reset the counter before starting creating connections.
new_sessions_allowed_per_event_loop_ = max_connections_to_create;
for (; new_sessions_allowed_per_event_loop_ > 0;
--new_sessions_allowed_per_event_loop_) {
QuicConnectionId server_connection_id;
BufferedPacketList packet_list =
buffered_packets_.DeliverPacketsForNextConnection(
&server_connection_id);
const std::list<BufferedPacket>& packets = packet_list.buffered_packets;
if (packets.empty()) {
return;
}
if (!packet_list.parsed_chlo.has_value()) {
QUIC_BUG(quic_dispatcher_no_parsed_chlo_in_buffered_packets)
<< "Buffered connection has no CHLO. connection_id:"
<< server_connection_id;
continue;
}
const ParsedClientHello& parsed_chlo = *packet_list.parsed_chlo;
QuicConnectionId original_connection_id = server_connection_id;
server_connection_id = MaybeReplaceServerConnectionId(server_connection_id,
packet_list.version);
std::string alpn = SelectAlpn(parsed_chlo.alpns);
std::unique_ptr<QuicSession> session = CreateQuicSession(
server_connection_id, packets.front().self_address,
packets.front().peer_address, alpn, packet_list.version, parsed_chlo);
if (original_connection_id != server_connection_id) {
session->connection()->SetOriginalDestinationConnectionId(
original_connection_id);
}
QUIC_DLOG(INFO) << "Created new session for " << server_connection_id;
auto insertion_result = reference_counted_session_map_.insert(
std::make_pair(server_connection_id,
std::shared_ptr<QuicSession>(std::move(session))));
if (!insertion_result.second) {
QUIC_BUG(quic_bug_12724_5)
<< "Tried to add a session to session_map with existing connection "
"id: "
<< server_connection_id;
} else {
++num_sessions_in_session_map_;
}
DeliverPacketsToSession(packets, insertion_result.first->second.get());
}
}
bool QuicDispatcher::HasChlosBuffered() const {
return buffered_packets_.HasChlosBuffered();
}
bool QuicDispatcher::ShouldCreateOrBufferPacketForConnection(
const ReceivedPacketInfo& packet_info) {
QUIC_VLOG(1) << "Received packet from new connection "
<< packet_info.destination_connection_id;
return true;
}
// Return true if there is any packet buffered in the store.
bool QuicDispatcher::HasBufferedPackets(QuicConnectionId server_connection_id) {
return buffered_packets_.HasBufferedPackets(server_connection_id);
}
void QuicDispatcher::OnBufferPacketFailure(
EnqueuePacketResult result,
QuicConnectionId server_connection_id) {
QUIC_DLOG(INFO) << "Fail to buffer packet on connection "
<< server_connection_id << " because of " << result;
}
QuicTimeWaitListManager* QuicDispatcher::CreateQuicTimeWaitListManager() {
return new QuicTimeWaitListManager(writer_.get(), this, helper_->GetClock(),
alarm_factory_.get());
}
void QuicDispatcher::BufferEarlyPacket(const ReceivedPacketInfo& packet_info) {
bool is_new_connection = !buffered_packets_.HasBufferedPackets(
packet_info.destination_connection_id);
if (is_new_connection &&
!ShouldCreateOrBufferPacketForConnection(packet_info)) {
return;
}
EnqueuePacketResult rs = buffered_packets_.EnqueuePacket(
packet_info.destination_connection_id,
packet_info.form != GOOGLE_QUIC_PACKET, packet_info.packet,
packet_info.self_address, packet_info.peer_address, packet_info.version,
/*parsed_chlo=*/absl::nullopt);
if (rs != EnqueuePacketResult::SUCCESS) {
OnBufferPacketFailure(rs, packet_info.destination_connection_id);
}
}
void QuicDispatcher::ProcessChlo(ParsedClientHello parsed_chlo,
ReceivedPacketInfo* packet_info) {
if (!buffered_packets_.HasBufferedPackets(
packet_info->destination_connection_id) &&
!ShouldCreateOrBufferPacketForConnection(*packet_info)) {
return;
}
if (GetQuicFlag(FLAGS_quic_allow_chlo_buffering) &&
new_sessions_allowed_per_event_loop_ <= 0) {
// Can't create new session any more. Wait till next event loop.
QUIC_BUG_IF(quic_bug_12724_7, buffered_packets_.HasChloForConnection(
packet_info->destination_connection_id));
EnqueuePacketResult rs = buffered_packets_.EnqueuePacket(
packet_info->destination_connection_id,
packet_info->form != GOOGLE_QUIC_PACKET, packet_info->packet,
packet_info->self_address, packet_info->peer_address,
packet_info->version, std::move(parsed_chlo));
if (rs != EnqueuePacketResult::SUCCESS) {
OnBufferPacketFailure(rs, packet_info->destination_connection_id);
}
return;
}
QuicConnectionId original_connection_id =
packet_info->destination_connection_id;
packet_info->destination_connection_id = MaybeReplaceServerConnectionId(
original_connection_id, packet_info->version);
// Creates a new session and process all buffered packets for this connection.
std::string alpn = SelectAlpn(parsed_chlo.alpns);
std::unique_ptr<QuicSession> session = CreateQuicSession(
packet_info->destination_connection_id, packet_info->self_address,
packet_info->peer_address, alpn, packet_info->version, parsed_chlo);
if (QUIC_PREDICT_FALSE(session == nullptr)) {
QUIC_BUG(quic_bug_10287_8)
<< "CreateQuicSession returned nullptr for "
<< packet_info->destination_connection_id << " from "
<< packet_info->peer_address << " to " << packet_info->self_address
<< " ALPN \"" << alpn << "\" version " << packet_info->version;
return;
}
if (original_connection_id != packet_info->destination_connection_id) {
session->connection()->SetOriginalDestinationConnectionId(
original_connection_id);
}
QUIC_DLOG(INFO) << "Created new session for "
<< packet_info->destination_connection_id;
QuicSession* session_ptr;
auto insertion_result = reference_counted_session_map_.insert(std::make_pair(
packet_info->destination_connection_id,
std::shared_ptr<QuicSession>(std::move(session.release()))));
if (!insertion_result.second) {
QUIC_BUG(quic_bug_10287_9)
<< "Tried to add a session to session_map with existing "
"connection id: "
<< packet_info->destination_connection_id;
} else {
++num_sessions_in_session_map_;
}
session_ptr = insertion_result.first->second.get();
std::list<BufferedPacket> packets =
buffered_packets_.DeliverPackets(packet_info->destination_connection_id)
.buffered_packets;
// Process CHLO at first.
session_ptr->ProcessUdpPacket(packet_info->self_address,
packet_info->peer_address, packet_info->packet);
// Deliver queued-up packets in the same order as they arrived.
// Do this even when flag is off because there might be still some packets
// buffered in the store before flag is turned off.
DeliverPacketsToSession(packets, session_ptr);
--new_sessions_allowed_per_event_loop_;
}
bool QuicDispatcher::ShouldDestroySessionAsynchronously() {
return true;
}
void QuicDispatcher::SetLastError(QuicErrorCode error) {
last_error_ = error;
}
bool QuicDispatcher::OnFailedToDispatchPacket(
const ReceivedPacketInfo& /*packet_info*/) {
return false;
}
const ParsedQuicVersionVector& QuicDispatcher::GetSupportedVersions() {
return version_manager_->GetSupportedVersions();
}
const ParsedQuicVersionVector&
QuicDispatcher::GetSupportedVersionsWithQuicCrypto() {
return version_manager_->GetSupportedVersionsWithQuicCrypto();
}
void QuicDispatcher::DeliverPacketsToSession(
const std::list<BufferedPacket>& packets,
QuicSession* session) {
for (const BufferedPacket& packet : packets) {
session->ProcessUdpPacket(packet.self_address, packet.peer_address,
*(packet.packet));
}
}
bool QuicDispatcher::IsSupportedVersion(const ParsedQuicVersion version) {
for (const ParsedQuicVersion& supported_version :
version_manager_->GetSupportedVersions()) {
if (version == supported_version) {
return true;
}
}
return false;
}
void QuicDispatcher::MaybeResetPacketsWithNoVersion(
const ReceivedPacketInfo& packet_info) {
QUICHE_DCHECK(!packet_info.version_flag);
// Do not send a stateless reset if a reset has been sent to this address
// recently.
if (recent_stateless_reset_addresses_.contains(packet_info.peer_address)) {
QUIC_CODE_COUNT(quic_donot_send_reset_repeatedly);
QUICHE_DCHECK(use_recent_reset_addresses_);
return;
}
if (packet_info.form != GOOGLE_QUIC_PACKET) {
// Drop IETF packets smaller than the minimal stateless reset length.
if (packet_info.packet.length() <=
QuicFramer::GetMinStatelessResetPacketLength()) {
QUIC_CODE_COUNT(quic_drop_too_small_short_header_packets);
return;
}
} else {
const size_t MinValidPacketLength =
kPacketHeaderTypeSize + expected_server_connection_id_length_ +
PACKET_1BYTE_PACKET_NUMBER + /*payload size=*/1 + /*tag size=*/12;
if (packet_info.packet.length() < MinValidPacketLength) {
// The packet size is too small.
QUIC_CODE_COUNT(drop_too_small_packets);
return;
}
}
if (use_recent_reset_addresses_) {
QUIC_RESTART_FLAG_COUNT(quic_use_recent_reset_addresses);
// Do not send a stateless reset if there are too many stateless reset
// addresses.
if (recent_stateless_reset_addresses_.size() >=
GetQuicFlag(FLAGS_quic_max_recent_stateless_reset_addresses)) {
QUIC_CODE_COUNT(quic_too_many_recent_reset_addresses);
return;
}
if (recent_stateless_reset_addresses_.empty()) {
clear_stateless_reset_addresses_alarm_->Update(
helper()->GetClock()->ApproximateNow() +
QuicTime::Delta::FromMilliseconds(GetQuicFlag(
FLAGS_quic_recent_stateless_reset_addresses_lifetime_ms)),
QuicTime::Delta::Zero());
}
recent_stateless_reset_addresses_.emplace(packet_info.peer_address);
}
time_wait_list_manager()->SendPublicReset(
packet_info.self_address, packet_info.peer_address,
packet_info.destination_connection_id,
packet_info.form != GOOGLE_QUIC_PACKET, packet_info.packet.length(),
GetPerPacketContext());
}
size_t QuicDispatcher::NumSessions() const {
return num_sessions_in_session_map_;
}
} // namespace quic