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quic_connection.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/quic/quic_connection.h"
#include <algorithm>
#include "base/logging.h"
#include "base/stl_util.h"
#include "net/quic/crypto/quic_decrypter.h"
#include "net/quic/crypto/quic_encrypter.h"
#include "net/quic/quic_utils.h"
using base::hash_map;
using base::hash_set;
using base::StringPiece;
using std::list;
using std::make_pair;
using std::min;
using std::max;
using std::vector;
using std::set;
using std::string;
namespace net {
namespace {
// The largest gap in packets we'll accept without closing the connection.
// This will likely have to be tuned.
const QuicPacketSequenceNumber kMaxPacketGap = 5000;
// We want to make sure if we get a large nack packet, we don't queue up too
// many packets at once. 10 is arbitrary.
const int kMaxRetransmissionsPerAck = 10;
// TCP retransmits after 2 nacks. We allow for a third in case of out-of-order
// delivery.
// TODO(ianswett): Change to match TCP's rule of retransmitting once an ack
// at least 3 sequence numbers larger arrives.
const size_t kNumberOfNacksBeforeRetransmission = 3;
// The maxiumum number of packets we'd like to queue. We may end up queueing
// more in the case of many control frames.
// 6 is arbitrary.
const int kMaxPacketsToSerializeAtOnce = 6;
// Limit the number of packets we send per retransmission-alarm so we
// eventually cede. 10 is arbitrary.
const size_t kMaxPacketsPerRetransmissionAlarm = 10;
// Limit the number of FEC groups to two. If we get enough out of order packets
// that this becomes limiting, we can revisit.
const size_t kMaxFecGroups = 2;
// Limit the number of undecryptable packets we buffer in
// expectation of the CHLO/SHLO arriving.
const size_t kMaxUndecryptablePackets = 10;
bool Near(QuicPacketSequenceNumber a, QuicPacketSequenceNumber b) {
QuicPacketSequenceNumber delta = (a > b) ? a - b : b - a;
return delta <= kMaxPacketGap;
}
// An alarm that is scheduled to send an ack if a timeout occurs.
class AckAlarm : public QuicAlarm::Delegate {
public:
explicit AckAlarm(QuicConnection* connection)
: connection_(connection) {
}
virtual QuicTime OnAlarm() OVERRIDE {
connection_->SendAck();
return QuicTime::Zero();
}
private:
QuicConnection* connection_;
};
// This alarm will be scheduled any time a data-bearing packet is sent out.
// When the alarm goes off, the connection checks to see if the oldest packets
// have been acked, and retransmit them if they have not.
class RetransmissionAlarm : public QuicAlarm::Delegate {
public:
explicit RetransmissionAlarm(QuicConnection* connection)
: connection_(connection) {
}
virtual QuicTime OnAlarm() OVERRIDE {
return connection_->OnRetransmissionTimeout();
}
private:
QuicConnection* connection_;
};
// An alarm that is scheduled when the sent scheduler requires a
// a delay before sending packets and fires when the packet may be sent.
class SendAlarm : public QuicAlarm::Delegate {
public:
explicit SendAlarm(QuicConnection* connection)
: connection_(connection) {
}
virtual QuicTime OnAlarm() OVERRIDE {
connection_->OnCanWrite();
// Never reschedule the alarm, since OnCanWrite does that.
return QuicTime::Zero();
}
private:
QuicConnection* connection_;
};
class TimeoutAlarm : public QuicAlarm::Delegate {
public:
explicit TimeoutAlarm(QuicConnection* connection)
: connection_(connection) {
}
virtual QuicTime OnAlarm() OVERRIDE {
connection_->CheckForTimeout();
// Never reschedule the alarm, since CheckForTimeout does that.
return QuicTime::Zero();
}
private:
QuicConnection* connection_;
};
} // namespace
#define ENDPOINT (is_server_ ? "Server: " : " Client: ")
QuicConnection::QuicConnection(QuicGuid guid,
IPEndPoint address,
QuicConnectionHelperInterface* helper,
bool is_server,
QuicVersion version)
: framer_(version,
helper->GetClock()->ApproximateNow(),
is_server),
helper_(helper),
encryption_level_(ENCRYPTION_NONE),
clock_(helper->GetClock()),
random_generator_(helper->GetRandomGenerator()),
guid_(guid),
peer_address_(address),
largest_seen_packet_with_ack_(0),
handling_retransmission_timeout_(false),
write_blocked_(false),
ack_alarm_(helper->CreateAlarm(new AckAlarm(this))),
retransmission_alarm_(helper->CreateAlarm(new RetransmissionAlarm(this))),
send_alarm_(helper->CreateAlarm(new SendAlarm(this))),
timeout_alarm_(helper->CreateAlarm(new TimeoutAlarm(this))),
debug_visitor_(NULL),
packet_creator_(guid_, &framer_, random_generator_, is_server),
packet_generator_(this, NULL, &packet_creator_),
idle_network_timeout_(
QuicTime::Delta::FromSeconds(kDefaultInitialTimeoutSecs)),
overall_connection_timeout_(QuicTime::Delta::Infinite()),
creation_time_(clock_->ApproximateNow()),
time_of_last_received_packet_(clock_->ApproximateNow()),
time_of_last_sent_packet_(clock_->ApproximateNow()),
congestion_manager_(clock_, kTCP),
version_negotiation_state_(START_NEGOTIATION),
max_packets_per_retransmission_alarm_(kMaxPacketsPerRetransmissionAlarm),
is_server_(is_server),
connected_(true),
received_truncated_ack_(false),
send_ack_in_response_to_packet_(false),
address_migrating_(false) {
helper_->SetConnection(this);
timeout_alarm_->Set(clock_->ApproximateNow().Add(idle_network_timeout_));
framer_.set_visitor(this);
framer_.set_received_entropy_calculator(&received_packet_manager_);
/*
if (FLAGS_fake_packet_loss_percentage > 0) {
int32 seed = RandomBase::WeakSeed32();
LOG(INFO) << ENDPOINT << "Seeding packet loss with " << seed;
random_.reset(new MTRandom(seed));
}
*/
}
QuicConnection::~QuicConnection() {
STLDeleteElements(&undecryptable_packets_);
STLDeleteValues(&unacked_packets_);
STLDeleteValues(&group_map_);
for (QueuedPacketList::iterator it = queued_packets_.begin();
it != queued_packets_.end(); ++it) {
delete it->packet;
}
}
bool QuicConnection::SelectMutualVersion(
const QuicVersionVector& available_versions) {
// Try to find the highest mutual version by iterating over supported
// versions, starting with the highest, and breaking out of the loop once we
// find a matching version in the provided available_versions vector.
for (size_t i = 0; i < arraysize(kSupportedQuicVersions); ++i) {
const QuicVersion& version = kSupportedQuicVersions[i];
if (std::find(available_versions.begin(), available_versions.end(),
version) != available_versions.end()) {
framer_.set_version(version);
return true;
}
}
return false;
}
void QuicConnection::OnError(QuicFramer* framer) {
// Packets that we cannot decrypt are dropped.
// TODO(rch): add stats to measure this.
if (!connected_ || framer->error() == QUIC_DECRYPTION_FAILURE) {
return;
}
SendConnectionClose(framer->error());
}
void QuicConnection::OnPacket() {
DCHECK(last_stream_frames_.empty() &&
last_goaway_frames_.empty() &&
last_rst_frames_.empty() &&
last_ack_frames_.empty() &&
last_congestion_frames_.empty());
}
void QuicConnection::OnPublicResetPacket(
const QuicPublicResetPacket& packet) {
if (debug_visitor_) {
debug_visitor_->OnPublicResetPacket(packet);
}
CloseConnection(QUIC_PUBLIC_RESET, true);
}
bool QuicConnection::OnProtocolVersionMismatch(QuicVersion received_version) {
// TODO(satyamshekhar): Implement no server state in this mode.
if (!is_server_) {
LOG(DFATAL) << ENDPOINT << "Framer called OnProtocolVersionMismatch. "
<< "Closing connection.";
CloseConnection(QUIC_INTERNAL_ERROR, false);
return false;
}
DCHECK_NE(version(), received_version);
if (debug_visitor_) {
debug_visitor_->OnProtocolVersionMismatch(received_version);
}
switch (version_negotiation_state_) {
case START_NEGOTIATION:
if (!framer_.IsSupportedVersion(received_version)) {
SendVersionNegotiationPacket();
version_negotiation_state_ = NEGOTIATION_IN_PROGRESS;
return false;
}
break;
case NEGOTIATION_IN_PROGRESS:
if (!framer_.IsSupportedVersion(received_version)) {
// Drop packets which can't be parsed due to version mismatch.
return false;
}
break;
case NEGOTIATED_VERSION:
// Might be old packets that were sent by the client before the version
// was negotiated. Drop these.
return false;
default:
DCHECK(false);
}
version_negotiation_state_ = NEGOTIATED_VERSION;
// Store the new version.
framer_.set_version(received_version);
// TODO(satyamshekhar): Store the sequence number of this packet and close the
// connection if we ever received a packet with incorrect version and whose
// sequence number is greater.
return true;
}
// Handles version negotiation for client connection.
void QuicConnection::OnVersionNegotiationPacket(
const QuicVersionNegotiationPacket& packet) {
if (is_server_) {
LOG(DFATAL) << ENDPOINT << "Framer parsed VersionNegotiationPacket."
<< " Closing connection.";
CloseConnection(QUIC_INTERNAL_ERROR, false);
return;
}
if (debug_visitor_) {
debug_visitor_->OnVersionNegotiationPacket(packet);
}
if (version_negotiation_state_ != START_NEGOTIATION) {
// Possibly a duplicate version negotiation packet.
return;
}
if (std::find(packet.versions.begin(),
packet.versions.end(), version()) !=
packet.versions.end()) {
DLOG(WARNING) << ENDPOINT << "The server already supports our version. "
<< "It should have accepted our connection.";
// Just drop the connection.
CloseConnection(QUIC_INVALID_VERSION_NEGOTIATION_PACKET, false);
return;
}
if (!SelectMutualVersion(packet.versions)) {
SendConnectionCloseWithDetails(QUIC_INVALID_VERSION,
"no common version found");
return;
}
version_negotiation_state_ = NEGOTIATION_IN_PROGRESS;
RetransmitUnackedPackets(ALL_PACKETS);
}
void QuicConnection::OnRevivedPacket() {
}
bool QuicConnection::OnPacketHeader(const QuicPacketHeader& header) {
if (debug_visitor_) {
debug_visitor_->OnPacketHeader(header);
}
if (!ProcessValidatedPacket()) {
return false;
}
// Will be decrement below if we fall through to return true;
++stats_.packets_dropped;
if (header.public_header.guid != guid_) {
DLOG(INFO) << ENDPOINT << "Ignoring packet from unexpected GUID: "
<< header.public_header.guid << " instead of " << guid_;
return false;
}
if (!Near(header.packet_sequence_number,
last_header_.packet_sequence_number)) {
DLOG(INFO) << ENDPOINT << "Packet " << header.packet_sequence_number
<< " out of bounds. Discarding";
SendConnectionCloseWithDetails(QUIC_INVALID_PACKET_HEADER,
"Packet sequence number out of bounds");
return false;
}
// If this packet has already been seen, or that the sender
// has told us will not be retransmitted, then stop processing the packet.
if (!received_packet_manager_.IsAwaitingPacket(
header.packet_sequence_number)) {
return false;
}
if (version_negotiation_state_ != NEGOTIATED_VERSION) {
if (is_server_) {
if (!header.public_header.version_flag) {
DLOG(WARNING) << ENDPOINT << "Got packet without version flag before "
<< "version negotiated.";
// Packets should have the version flag till version negotiation is
// done.
CloseConnection(QUIC_INVALID_VERSION, false);
return false;
} else {
DCHECK_EQ(1u, header.public_header.versions.size());
DCHECK_EQ(header.public_header.versions[0], version());
version_negotiation_state_ = NEGOTIATED_VERSION;
}
} else {
DCHECK(!header.public_header.version_flag);
// If the client gets a packet without the version flag from the server
// it should stop sending version since the version negotiation is done.
packet_creator_.StopSendingVersion();
version_negotiation_state_ = NEGOTIATED_VERSION;
}
}
DCHECK_EQ(NEGOTIATED_VERSION, version_negotiation_state_);
--stats_.packets_dropped;
DVLOG(1) << ENDPOINT << "Received packet header: " << header;
last_header_ = header;
DCHECK(connected_);
return true;
}
void QuicConnection::OnFecProtectedPayload(StringPiece payload) {
DCHECK_EQ(IN_FEC_GROUP, last_header_.is_in_fec_group);
DCHECK_NE(0u, last_header_.fec_group);
QuicFecGroup* group = GetFecGroup();
if (group != NULL) {
group->Update(last_header_, payload);
}
}
bool QuicConnection::OnStreamFrame(const QuicStreamFrame& frame) {
DCHECK(connected_);
if (debug_visitor_) {
debug_visitor_->OnStreamFrame(frame);
}
last_stream_frames_.push_back(frame);
return true;
}
bool QuicConnection::OnAckFrame(const QuicAckFrame& incoming_ack) {
DCHECK(connected_);
if (debug_visitor_) {
debug_visitor_->OnAckFrame(incoming_ack);
}
DVLOG(1) << ENDPOINT << "OnAckFrame: " << incoming_ack;
if (last_header_.packet_sequence_number <= largest_seen_packet_with_ack_) {
DLOG(INFO) << ENDPOINT << "Received an old ack frame: ignoring";
return true;
}
if (!ValidateAckFrame(incoming_ack)) {
SendConnectionClose(QUIC_INVALID_ACK_DATA);
return false;
}
last_ack_frames_.push_back(incoming_ack);
return connected_;
}
void QuicConnection::ProcessAckFrame(const QuicAckFrame& incoming_ack) {
largest_seen_packet_with_ack_ = last_header_.packet_sequence_number;
received_truncated_ack_ =
incoming_ack.received_info.missing_packets.size() >=
QuicFramer::GetMaxUnackedPackets(last_header_);
received_packet_manager_.UpdatePacketInformationReceivedByPeer(incoming_ack);
received_packet_manager_.UpdatePacketInformationSentByPeer(incoming_ack);
// Possibly close any FecGroups which are now irrelevant.
CloseFecGroupsBefore(incoming_ack.sent_info.least_unacked + 1);
sent_entropy_manager_.ClearEntropyBefore(
received_packet_manager_.least_packet_awaited_by_peer() - 1);
SequenceNumberSet acked_packets;
HandleAckForSentPackets(incoming_ack, &acked_packets);
HandleAckForSentFecPackets(incoming_ack, &acked_packets);
if (acked_packets.size() > 0) {
visitor_->OnAck(acked_packets);
}
congestion_manager_.OnIncomingAckFrame(incoming_ack,
time_of_last_received_packet_);
}
bool QuicConnection::OnCongestionFeedbackFrame(
const QuicCongestionFeedbackFrame& feedback) {
DCHECK(connected_);
if (debug_visitor_) {
debug_visitor_->OnCongestionFeedbackFrame(feedback);
}
last_congestion_frames_.push_back(feedback);
return connected_;
}
bool QuicConnection::ValidateAckFrame(const QuicAckFrame& incoming_ack) {
if (incoming_ack.received_info.largest_observed >
packet_creator_.sequence_number()) {
DLOG(ERROR) << ENDPOINT << "Peer's observed unsent packet:"
<< incoming_ack.received_info.largest_observed << " vs "
<< packet_creator_.sequence_number();
// We got an error for data we have not sent. Error out.
return false;
}
if (incoming_ack.received_info.largest_observed <
received_packet_manager_.peer_largest_observed_packet()) {
DLOG(ERROR) << ENDPOINT << "Peer's largest_observed packet decreased:"
<< incoming_ack.received_info.largest_observed << " vs "
<< received_packet_manager_.peer_largest_observed_packet();
// A new ack has a diminished largest_observed value. Error out.
// If this was an old packet, we wouldn't even have checked.
return false;
}
// We can't have too many unacked packets, or our ack frames go over
// kMaxPacketSize.
DCHECK_LE(incoming_ack.received_info.missing_packets.size(),
QuicFramer::GetMaxUnackedPackets(last_header_));
if (incoming_ack.sent_info.least_unacked <
received_packet_manager_.peer_least_packet_awaiting_ack()) {
DLOG(ERROR) << ENDPOINT << "Peer's sent low least_unacked: "
<< incoming_ack.sent_info.least_unacked << " vs "
<< received_packet_manager_.peer_least_packet_awaiting_ack();
// We never process old ack frames, so this number should only increase.
return false;
}
if (incoming_ack.sent_info.least_unacked >
last_header_.packet_sequence_number) {
DLOG(ERROR) << ENDPOINT << "Peer sent least_unacked:"
<< incoming_ack.sent_info.least_unacked
<< " greater than the enclosing packet sequence number:"
<< last_header_.packet_sequence_number;
return false;
}
if (!incoming_ack.received_info.missing_packets.empty() &&
*incoming_ack.received_info.missing_packets.rbegin() >
incoming_ack.received_info.largest_observed) {
DLOG(ERROR) << ENDPOINT << "Peer sent missing packet: "
<< *incoming_ack.received_info.missing_packets.rbegin()
<< " greater than largest observed: "
<< incoming_ack.received_info.largest_observed;
return false;
}
if (!incoming_ack.received_info.missing_packets.empty() &&
*incoming_ack.received_info.missing_packets.begin() <
received_packet_manager_.least_packet_awaited_by_peer()) {
DLOG(ERROR) << ENDPOINT << "Peer sent missing packet: "
<< *incoming_ack.received_info.missing_packets.begin()
<< "smaller than least_packet_awaited_by_peer_: "
<< received_packet_manager_.least_packet_awaited_by_peer();
return false;
}
if (!sent_entropy_manager_.IsValidEntropy(
incoming_ack.received_info.largest_observed,
incoming_ack.received_info.missing_packets,
incoming_ack.received_info.entropy_hash)) {
DLOG(ERROR) << ENDPOINT << "Peer sent invalid entropy.";
return false;
}
return true;
}
void QuicConnection::HandleAckForSentPackets(const QuicAckFrame& incoming_ack,
SequenceNumberSet* acked_packets) {
int retransmitted_packets = 0;
// Go through the packets we have not received an ack for and see if this
// incoming_ack shows they've been seen by the peer.
UnackedPacketMap::iterator it = unacked_packets_.begin();
while (it != unacked_packets_.end()) {
QuicPacketSequenceNumber sequence_number = it->first;
if (sequence_number >
received_packet_manager_.peer_largest_observed_packet()) {
// These are very new sequence_numbers.
break;
}
RetransmittableFrames* unacked = it->second;
if (!IsAwaitingPacket(incoming_ack.received_info, sequence_number)) {
// Packet was acked, so remove it from our unacked packet list.
DVLOG(1) << ENDPOINT <<"Got an ack for packet " << sequence_number;
acked_packets->insert(sequence_number);
delete unacked;
unacked_packets_.erase(it++);
retransmission_map_.erase(sequence_number);
} else {
// This is a packet which we planned on retransmitting and has not been
// seen at the time of this ack being sent out. See if it's our new
// lowest unacked packet.
DVLOG(1) << ENDPOINT << "still missing packet " << sequence_number;
++it;
// The peer got packets after this sequence number. This is an explicit
// nack.
RetransmissionMap::iterator retransmission_it =
retransmission_map_.find(sequence_number);
++(retransmission_it->second.number_nacks);
if (retransmission_it->second.number_nacks >=
kNumberOfNacksBeforeRetransmission &&
retransmitted_packets < kMaxRetransmissionsPerAck) {
++retransmitted_packets;
DVLOG(1) << ENDPOINT << "Trying to retransmit packet "
<< sequence_number
<< " as it has been nacked 3 or more times.";
// RetransmitPacket will retransmit with a new sequence_number.
RetransmitPacket(sequence_number);
}
}
}
}
void QuicConnection::HandleAckForSentFecPackets(
const QuicAckFrame& incoming_ack, SequenceNumberSet* acked_packets) {
UnackedPacketMap::iterator it = unacked_fec_packets_.begin();
while (it != unacked_fec_packets_.end()) {
QuicPacketSequenceNumber sequence_number = it->first;
if (sequence_number >
received_packet_manager_.peer_largest_observed_packet()) {
break;
}
if (!IsAwaitingPacket(incoming_ack.received_info, sequence_number)) {
DVLOG(1) << ENDPOINT << "Got an ack for fec packet: " << sequence_number;
acked_packets->insert(sequence_number);
unacked_fec_packets_.erase(it++);
} else {
DVLOG(1) << ENDPOINT << "Still missing ack for fec packet: "
<< sequence_number;
++it;
}
}
}
void QuicConnection::OnFecData(const QuicFecData& fec) {
DCHECK_EQ(IN_FEC_GROUP, last_header_.is_in_fec_group);
DCHECK_NE(0u, last_header_.fec_group);
QuicFecGroup* group = GetFecGroup();
if (group != NULL) {
group->UpdateFec(last_header_.packet_sequence_number,
last_header_.entropy_flag, fec);
}
}
bool QuicConnection::OnRstStreamFrame(const QuicRstStreamFrame& frame) {
DCHECK(connected_);
if (debug_visitor_) {
debug_visitor_->OnRstStreamFrame(frame);
}
DLOG(INFO) << ENDPOINT << "Stream reset with error "
<< QuicUtils::StreamErrorToString(frame.error_code);
last_rst_frames_.push_back(frame);
return connected_;
}
bool QuicConnection::OnConnectionCloseFrame(
const QuicConnectionCloseFrame& frame) {
DCHECK(connected_);
if (debug_visitor_) {
debug_visitor_->OnConnectionCloseFrame(frame);
}
DLOG(INFO) << ENDPOINT << "Connection closed with error "
<< QuicUtils::ErrorToString(frame.error_code)
<< " " << frame.error_details;
CloseConnection(frame.error_code, true);
DCHECK(!connected_);
return false;
}
bool QuicConnection::OnGoAwayFrame(const QuicGoAwayFrame& frame) {
DCHECK(connected_);
DLOG(INFO) << ENDPOINT << "Go away received with error "
<< QuicUtils::ErrorToString(frame.error_code)
<< " and reason:" << frame.reason_phrase;
last_goaway_frames_.push_back(frame);
return connected_;
}
void QuicConnection::OnPacketComplete() {
// Don't do anything if this packet closed the connection.
if (!connected_) {
ClearLastFrames();
return;
}
DLOG(INFO) << ENDPOINT << (last_packet_revived_ ? "Revived" : "Got")
<< " packet " << last_header_.packet_sequence_number
<< " with " << last_ack_frames_.size() << " acks, "
<< last_congestion_frames_.size() << " congestions, "
<< last_goaway_frames_.size() << " goaways, "
<< last_rst_frames_.size() << " rsts, "
<< last_stream_frames_.size()
<< " stream frames for " << last_header_.public_header.guid;
if (!last_packet_revived_) {
congestion_manager_.RecordIncomingPacket(
last_size_, last_header_.packet_sequence_number,
time_of_last_received_packet_, last_packet_revived_);
}
// Must called before ack processing, because processing acks removes entries
// from unacket_packets_, increasing the least_unacked.
const bool last_packet_should_instigate_ack = ShouldLastPacketInstigateAck();
if ((last_stream_frames_.empty() ||
visitor_->OnPacket(self_address_, peer_address_,
last_header_, last_stream_frames_))) {
received_packet_manager_.RecordPacketReceived(
last_header_, time_of_last_received_packet_);
}
// Process stream resets, then acks, then congestion feedback.
for (size_t i = 0; i < last_goaway_frames_.size(); ++i) {
visitor_->OnGoAway(last_goaway_frames_[i]);
}
for (size_t i = 0; i < last_rst_frames_.size(); ++i) {
visitor_->OnRstStream(last_rst_frames_[i]);
}
for (size_t i = 0; i < last_ack_frames_.size(); ++i) {
ProcessAckFrame(last_ack_frames_[i]);
}
for (size_t i = 0; i < last_congestion_frames_.size(); ++i) {
congestion_manager_.OnIncomingQuicCongestionFeedbackFrame(
last_congestion_frames_[i], time_of_last_received_packet_);
}
MaybeSendInResponseToPacket(last_packet_should_instigate_ack);
ClearLastFrames();
}
void QuicConnection::ClearLastFrames() {
last_stream_frames_.clear();
last_goaway_frames_.clear();
last_rst_frames_.clear();
last_ack_frames_.clear();
last_congestion_frames_.clear();
}
QuicAckFrame* QuicConnection::CreateAckFrame() {
QuicAckFrame* outgoing_ack = new QuicAckFrame();
received_packet_manager_.UpdateReceivedPacketInfo(
&(outgoing_ack->received_info), clock_->ApproximateNow());
UpdateSentPacketInfo(&(outgoing_ack->sent_info));
DVLOG(1) << ENDPOINT << "Creating ack frame: " << *outgoing_ack;
return outgoing_ack;
}
QuicCongestionFeedbackFrame* QuicConnection::CreateFeedbackFrame() {
return new QuicCongestionFeedbackFrame(outgoing_congestion_feedback_);
}
bool QuicConnection::ShouldLastPacketInstigateAck() {
if (!last_stream_frames_.empty() ||
!last_goaway_frames_.empty() ||
!last_rst_frames_.empty()) {
return true;
}
// If the peer is still waiting for a packet that we are no
// longer planning to send, we should send an ack to raise
// the high water mark.
if (!last_ack_frames_.empty() &&
!last_ack_frames_.back().received_info.missing_packets.empty() &&
!unacked_packets_.empty()) {
if (unacked_packets_.begin()->first >
*last_ack_frames_.back().received_info.missing_packets.begin()) {
return true;
}
}
return false;
}
void QuicConnection::MaybeSendInResponseToPacket(
bool last_packet_should_instigate_ack) {
// TODO(ianswett): Better merge these two blocks to queue up an ack if
// necessary, then either only send the ack or bundle it with other data.
if (!last_ack_frames_.empty()) {
// Now the we have received an ack, we might be able to send packets which
// are queued locally, or drain streams which are blocked.
QuicTime::Delta delay = congestion_manager_.TimeUntilSend(
time_of_last_received_packet_, NOT_RETRANSMISSION,
HAS_RETRANSMITTABLE_DATA, NOT_HANDSHAKE);
if (delay.IsZero()) {
send_alarm_->Cancel();
WriteIfNotBlocked();
} else if (!delay.IsInfinite()) {
send_alarm_->Cancel();
send_alarm_->Set(time_of_last_received_packet_.Add(delay));
}
}
if (!last_packet_should_instigate_ack) {
return;
}
if (send_ack_in_response_to_packet_) {
SendAck();
} else if (!last_stream_frames_.empty()) {
// TODO(alyssar) this case should really be "if the packet contained any
// non-ack frame", rather than "if the packet contained a stream frame"
if (!ack_alarm_->IsSet()) {
ack_alarm_->Set(clock_->ApproximateNow().Add(
congestion_manager_.DefaultRetransmissionTime()));
}
}
send_ack_in_response_to_packet_ = !send_ack_in_response_to_packet_;
}
void QuicConnection::SendVersionNegotiationPacket() {
QuicVersionVector supported_versions;
for (size_t i = 0; i < arraysize(kSupportedQuicVersions); ++i) {
supported_versions.push_back(kSupportedQuicVersions[i]);
}
QuicEncryptedPacket* encrypted =
packet_creator_.SerializeVersionNegotiationPacket(supported_versions);
// TODO(satyamshekhar): implement zero server state negotiation.
int error;
helper_->WritePacketToWire(*encrypted, &error);
delete encrypted;
}
QuicConsumedData QuicConnection::SendStreamData(QuicStreamId id,
StringPiece data,
QuicStreamOffset offset,
bool fin) {
return packet_generator_.ConsumeData(id, data, offset, fin);
}
void QuicConnection::SendRstStream(QuicStreamId id,
QuicRstStreamErrorCode error) {
packet_generator_.AddControlFrame(
QuicFrame(new QuicRstStreamFrame(id, error)));
}
const QuicConnectionStats& QuicConnection::GetStats() {
// Update rtt and estimated bandwidth.
stats_.rtt = congestion_manager_.SmoothedRtt().ToMicroseconds();
stats_.estimated_bandwidth =
congestion_manager_.BandwidthEstimate().ToBytesPerSecond();
return stats_;
}
void QuicConnection::ProcessUdpPacket(const IPEndPoint& self_address,
const IPEndPoint& peer_address,
const QuicEncryptedPacket& packet) {
if (!connected_) {
return;
}
if (debug_visitor_) {
debug_visitor_->OnPacketReceived(self_address, peer_address, packet);
}
last_packet_revived_ = false;
last_size_ = packet.length();
address_migrating_ = false;
if (peer_address_.address().empty()) {
peer_address_ = peer_address;
}
if (self_address_.address().empty()) {
self_address_ = self_address;
}
if (!(peer_address == peer_address_ && self_address == self_address_)) {
address_migrating_ = true;
}
stats_.bytes_received += packet.length();
++stats_.packets_received;
if (!framer_.ProcessPacket(packet)) {
// If we are unable to decrypt this packet, it might be
// because the CHLO or SHLO packet was lost.
if (encryption_level_ != ENCRYPTION_FORWARD_SECURE &&
framer_.error() == QUIC_DECRYPTION_FAILURE &&
undecryptable_packets_.size() < kMaxUndecryptablePackets) {
QueueUndecryptablePacket(packet);
}
DVLOG(1) << ENDPOINT << "Unable to process packet. Last packet processed: "
<< last_header_.packet_sequence_number;
return;
}
MaybeProcessUndecryptablePackets();
MaybeProcessRevivedPacket();
}
bool QuicConnection::OnCanWrite() {
write_blocked_ = false;
return DoWrite();
}
bool QuicConnection::WriteIfNotBlocked() {
if (write_blocked_) {
return false;
}
return DoWrite();
}
bool QuicConnection::DoWrite() {
DCHECK(!write_blocked_);
WriteQueuedPackets();
// Sending queued packets may have caused the socket to become write blocked,
// or the congestion manager to prohibit sending. If we've sent everything
// we had queued and we're still not blocked, let the visitor know it can
// write more.
if (CanWrite(NOT_RETRANSMISSION, HAS_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
packet_generator_.StartBatchOperations();
bool all_bytes_written = visitor_->OnCanWrite();
packet_generator_.FinishBatchOperations();
// After the visitor writes, it may have caused the socket to become write
// blocked or the congestion manager to prohibit sending, so check again.
if (!write_blocked_ && !all_bytes_written &&
CanWrite(NOT_RETRANSMISSION, HAS_RETRANSMITTABLE_DATA,
NOT_HANDSHAKE)) {
// We're not write blocked, but some stream didn't write out all of its
// bytes. Register for 'immediate' resumption so we'll keep writing after
// other quic connections have had a chance to use the socket.
send_alarm_->Cancel();
send_alarm_->Set(clock_->ApproximateNow());
}
}
return !write_blocked_;
}
bool QuicConnection::ProcessValidatedPacket() {
if (address_migrating_) {
SendConnectionCloseWithDetails(
QUIC_ERROR_MIGRATING_ADDRESS,
"Address migration is not yet a supported feature");
return false;
}
time_of_last_received_packet_ = clock_->Now();
DVLOG(1) << ENDPOINT << "time of last received packet: "
<< time_of_last_received_packet_.ToDebuggingValue();
return true;
}
bool QuicConnection::WriteQueuedPackets() {
DCHECK(!write_blocked_);
size_t num_queued_packets = queued_packets_.size() + 1;
QueuedPacketList::iterator packet_iterator = queued_packets_.begin();
while (!write_blocked_ && packet_iterator != queued_packets_.end()) {
// Ensure that from one iteration of this loop to the next we
// succeeded in sending a packet so we don't infinitely loop.
// TODO(rch): clean up and close the connection if we really hit this.
DCHECK_LT(queued_packets_.size(), num_queued_packets);
num_queued_packets = queued_packets_.size();
if (WritePacket(packet_iterator->encryption_level,
packet_iterator->sequence_number,
packet_iterator->packet,
packet_iterator->retransmittable,
NO_FORCE)) {
packet_iterator = queued_packets_.erase(packet_iterator);
} else {
// Continue, because some queued packets may still be writable.
// This can happen if a retransmit send fail.
++packet_iterator;
}
}
return !write_blocked_;
}
bool QuicConnection::MaybeRetransmitPacketForRTO(
QuicPacketSequenceNumber sequence_number) {
DCHECK_EQ(ContainsKey(unacked_packets_, sequence_number),
ContainsKey(retransmission_map_, sequence_number));
if (!ContainsKey(unacked_packets_, sequence_number)) {
DVLOG(2) << ENDPOINT << "alarm fired for " << sequence_number
<< " but it has been acked or already retransmitted with"
<< " different sequence number.";
// So no extra delay is added for this packet.
return true;
}
RetransmissionMap::iterator retransmission_it =
retransmission_map_.find(sequence_number);
// If the packet hasn't been acked and we're getting truncated acks, ignore
// any RTO for packets larger than the peer's largest observed packet; it may
// have been received by the peer and just wasn't acked due to the ack frame
// running out of space.
if (received_truncated_ack_ && sequence_number >
received_packet_manager_.peer_largest_observed_packet() &&
// We allow retransmission of already retransmitted packets so that we
// retransmit packets that were retransmissions of the packet with
// sequence number < the largest observed field of the truncated ack.
retransmission_it->second.number_retransmissions == 0) {
return false;
} else {
++stats_.rto_count;
RetransmitPacket(sequence_number);
return true;
}
}
void QuicConnection::RetransmitUnackedPackets(
RetransmissionType retransmission_type) {
if (unacked_packets_.empty()) {
return;
}
UnackedPacketMap::iterator next_it = unacked_packets_.begin();
QuicPacketSequenceNumber end_sequence_number =
unacked_packets_.rbegin()->first;
do {
UnackedPacketMap::iterator current_it = next_it;
++next_it;
if (retransmission_type == ALL_PACKETS ||
current_it->second->encryption_level() == ENCRYPTION_INITIAL) {
// TODO(satyamshekhar): Think about congestion control here.
// Specifically, about the retransmission count of packets being sent
// proactively to achieve 0 (minimal) RTT.
RetransmitPacket(current_it->first);
}
} while (next_it != unacked_packets_.end() &&
next_it->first <= end_sequence_number);