Google Git
Sign in
android / platform / external / chromium_org / 0bdaf95291fc46702f274f40e8e5081e9ef23011 / . / net / quic / quic_framer.cc
blob: 493cf807b1fde08fbaac1cb0f8a805888c623e37 [file] [log] [blame]
// 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_framer.h"
#include "base/containers/hash_tables.h"
#include "net/quic/crypto/quic_decrypter.h"
#include "net/quic/crypto/quic_encrypter.h"
#include "net/quic/quic_data_reader.h"
#include "net/quic/quic_data_writer.h"
using base::StringPiece;
using std::make_pair;
using std::map;
using std::numeric_limits;
using std::string;
namespace net {
namespace {
// TODO(jri): Remove uses of QuicFrameTypeOld when
// QUIC versions < 10 are no longer supported.
enum QuicFrameTypeOld {
PADDING_FRAME_OLD = 0,
STREAM_FRAME_OLD,
ACK_FRAME_OLD,
CONGESTION_FEEDBACK_FRAME_OLD,
RST_STREAM_FRAME_OLD,
CONNECTION_CLOSE_FRAME_OLD,
GOAWAY_FRAME_OLD,
NUM_FRAME_TYPES_OLD
};
// Mask to select the lowest 48 bits of a sequence number.
const QuicPacketSequenceNumber k6ByteSequenceNumberMask =
GG_UINT64_C(0x0000FFFFFFFFFFFF);
const QuicPacketSequenceNumber k4ByteSequenceNumberMask =
GG_UINT64_C(0x00000000FFFFFFFF);
const QuicPacketSequenceNumber k2ByteSequenceNumberMask =
GG_UINT64_C(0x000000000000FFFF);
const QuicPacketSequenceNumber k1ByteSequenceNumberMask =
GG_UINT64_C(0x00000000000000FF);
const QuicGuid k1ByteGuidMask = GG_UINT64_C(0x00000000000000FF);
const QuicGuid k4ByteGuidMask = GG_UINT64_C(0x00000000FFFFFFFF);
// New Frame Types, QUIC v. >= 10:
// There are two interpretations for the Frame Type byte in the QUIC protocol,
// resulting in two Frame Types: Special Frame Types and Regular Frame Types.
//
// Regular Frame Types use the Frame Type byte simply. Currently defined
// Regular Frame Types are:
// Padding : 0b 00000000 (0x00)
// ResetStream : 0b 00000001 (0x01)
// ConnectionClose : 0b 00000010 (0x02)
// GoAway : 0b 00000011 (0x03)
//
// Special Frame Types encode both a Frame Type and corresponding flags
// all in the Frame Type byte. Currently defined Special Frame Types are:
// Stream : 0b 1xxxxxxx
// Ack : 0b 01xxxxxx
// CongestionFeedback : 0b 001xxxxx
//
// Semantics of the flag bits above (the x bits) depends on the frame type.
// Masks to determine if the frame type is a special use
// and for specific special frame types.
const uint8 kQuicFrameTypeSpecialMask = 0xE0; // 0b 11100000
const uint8 kQuicFrameTypeStreamMask = 0x80;
const uint8 kQuicFrameTypeAckMask = 0x40;
const uint8 kQuicFrameTypeCongestionFeedbackMask = 0x20;
// Stream frame relative shifts and masks for interpreting the stream flags.
// StreamID may be 1, 2, 3, or 4 bytes.
const uint8 kQuicStreamIdShift = 2;
const uint8 kQuicStreamIDLengthMask = 0x03;
// Offset may be 0, 2, 3, 4, 5, 6, 7, 8 bytes.
const uint8 kQuicStreamOffsetShift = 3;
const uint8 kQuicStreamOffsetMask = 0x07;
// Data length may be 0 or 2 bytes.
const uint8 kQuicStreamDataLengthShift = 1;
const uint8 kQuicStreamDataLengthMask = 0x01;
// Fin bit may be set or not.
const uint8 kQuicStreamFinShift = 1;
const uint8 kQuicStreamFinMask = 0x01;
const uint32 kInvalidDeltaTime = 0xffffffff;
// Returns the absolute value of the difference between |a| and |b|.
QuicPacketSequenceNumber Delta(QuicPacketSequenceNumber a,
QuicPacketSequenceNumber b) {
// Since these are unsigned numbers, we can't just return abs(a - b)
if (a < b) {
return b - a;
}
return a - b;
}
QuicPacketSequenceNumber ClosestTo(QuicPacketSequenceNumber target,
QuicPacketSequenceNumber a,
QuicPacketSequenceNumber b) {
return (Delta(target, a) < Delta(target, b)) ? a : b;
}
QuicTag GetNullTag(QuicVersion version) {
return version >= QUIC_VERSION_11 ? kNULN : kNULL;
}
} // namespace
QuicFramer::QuicFramer(const QuicVersionVector& supported_versions,
QuicTime creation_time,
bool is_server)
: visitor_(NULL),
fec_builder_(NULL),
error_(QUIC_NO_ERROR),
last_sequence_number_(0),
last_serialized_guid_(0),
supported_versions_(supported_versions),
alternative_decrypter_latch_(false),
is_server_(is_server),
creation_time_(creation_time) {
DCHECK(!supported_versions.empty());
quic_version_ = supported_versions_[0];
decrypter_.reset(QuicDecrypter::Create(GetNullTag(quic_version_)));
encrypter_[ENCRYPTION_NONE].reset(
QuicEncrypter::Create(GetNullTag(quic_version_)));
}
QuicFramer::~QuicFramer() {}
// static
size_t QuicFramer::GetMinStreamFrameSize(QuicVersion version,
QuicStreamId stream_id,
QuicStreamOffset offset,
bool last_frame_in_packet) {
return kQuicFrameTypeSize + GetStreamIdSize(stream_id) +
GetStreamOffsetSize(offset) +
(last_frame_in_packet ? 0 : kQuicStreamPayloadLengthSize);
}
// static
size_t QuicFramer::GetMinAckFrameSize() {
return kQuicFrameTypeSize + kQuicEntropyHashSize +
PACKET_6BYTE_SEQUENCE_NUMBER + kQuicEntropyHashSize +
PACKET_6BYTE_SEQUENCE_NUMBER + kQuicDeltaTimeLargestObservedSize +
kNumberOfMissingPacketsSize;
}
// static
size_t QuicFramer::GetMinRstStreamFrameSize() {
return kQuicFrameTypeSize + kQuicMaxStreamIdSize + kQuicErrorCodeSize +
kQuicErrorDetailsLengthSize;
}
// static
size_t QuicFramer::GetMinConnectionCloseFrameSize() {
return kQuicFrameTypeSize + kQuicErrorCodeSize + kQuicErrorDetailsLengthSize +
GetMinAckFrameSize() - 1; // Don't include the frame type again.
}
// static
size_t QuicFramer::GetMinGoAwayFrameSize() {
return kQuicFrameTypeSize + kQuicErrorCodeSize + kQuicErrorDetailsLengthSize +
kQuicMaxStreamIdSize;
}
// static
// TODO(satyamshekhar): 16 - Crypto hash for integrity. Not a static value. Use
// QuicEncrypter::GetMaxPlaintextSize.
// 16 is a conservative estimate in the case of AEAD_AES_128_GCM_12, which uses
// 12-byte tags.
size_t QuicFramer::GetMaxUnackedPackets(QuicPacketHeader header) {
return (kMaxPacketSize - GetPacketHeaderSize(header) -
GetMinAckFrameSize() - 16) / PACKET_6BYTE_SEQUENCE_NUMBER;
}
// static
size_t QuicFramer::GetStreamIdSize(QuicStreamId stream_id) {
// Sizes are 1 through 4 bytes.
for (int i = 1; i <= 4; ++i) {
stream_id >>= 8;
if (stream_id == 0) {
return i;
}
}
LOG(DFATAL) << "Failed to determine StreamIDSize.";
return 4;
}
// static
size_t QuicFramer::GetStreamOffsetSize(QuicStreamOffset offset) {
// 0 is a special case.
if (offset == 0) {
return 0;
}
// 2 through 8 are the remaining sizes.
offset >>= 8;
for (int i = 2; i <= 8; ++i) {
offset >>= 8;
if (offset == 0) {
return i;
}
}
LOG(DFATAL) << "Failed to determine StreamOffsetSize.";
return 8;
}
// static
size_t QuicFramer::GetVersionNegotiationPacketSize(size_t number_versions) {
return kPublicFlagsSize + PACKET_8BYTE_GUID +
number_versions * kQuicVersionSize;
}
// static
bool QuicFramer::CanTruncate(const QuicFrame& frame, size_t free_bytes) {
// TODO(ianswett): GetMinConnectionCloseFrameSize may be incorrect, because
// checking for it here results in frames not being added, but the resulting
// frames do actually fit.
if ((frame.type == ACK_FRAME || frame.type == CONNECTION_CLOSE_FRAME) &&
free_bytes >= GetMinAckFrameSize()) {
return true;
}
return false;
}
bool QuicFramer::IsSupportedVersion(const QuicVersion version) const {
for (size_t i = 0; i < supported_versions_.size(); ++i) {
if (version == supported_versions_[i]) {
return true;
}
}
return false;
}
size_t QuicFramer::GetSerializedFrameLength(const QuicFrame& frame,
size_t free_bytes,
bool first_frame,
bool last_frame) {
if (frame.type == PADDING_FRAME) {
// PADDING implies end of packet.
return free_bytes;
}
size_t frame_len = ComputeFrameLength(frame, last_frame);
if (frame_len > free_bytes) {
// Only truncate the first frame in a packet, so if subsequent ones go
// over, stop including more frames.
if (!first_frame) {
return 0;
}
if (CanTruncate(frame, free_bytes)) {
// Truncate the frame so the packet will not exceed kMaxPacketSize.
// Note that we may not use every byte of the writer in this case.
DLOG(INFO) << "Truncating large frame";
return free_bytes;
}
}
return frame_len;
}
QuicPacketEntropyHash QuicFramer::GetPacketEntropyHash(
const QuicPacketHeader& header) const {
if (!header.entropy_flag) {
// TODO(satyamshekhar): Return some more better value here (something that
// is not a constant).
return 0;
}
return 1 << (header.packet_sequence_number % 8);
}
SerializedPacket QuicFramer::BuildUnsizedDataPacket(
const QuicPacketHeader& header,
const QuicFrames& frames) {
const size_t max_plaintext_size = GetMaxPlaintextSize(kMaxPacketSize);
size_t packet_size = GetPacketHeaderSize(header);
for (size_t i = 0; i < frames.size(); ++i) {
DCHECK_LE(packet_size, max_plaintext_size);
bool first_frame = i == 0;
bool last_frame = i == frames.size() - 1;
const size_t frame_size = GetSerializedFrameLength(
frames[i], max_plaintext_size - packet_size, first_frame, last_frame);
DCHECK(frame_size);
packet_size += frame_size;
}
return BuildDataPacket(header, frames, packet_size);
}
SerializedPacket QuicFramer::BuildDataPacket(
const QuicPacketHeader& header,
const QuicFrames& frames,
size_t packet_size) {
QuicDataWriter writer(packet_size);
const SerializedPacket kNoPacket(
0, PACKET_1BYTE_SEQUENCE_NUMBER, NULL, 0, NULL);
if (!WritePacketHeader(header, &writer)) {
return kNoPacket;
}
for (size_t i = 0; i < frames.size(); ++i) {
const QuicFrame& frame = frames[i];
const bool last_frame_in_packet = i == (frames.size() - 1);
if (!AppendTypeByte(frame, last_frame_in_packet, &writer)) {
return kNoPacket;
}
switch (frame.type) {
case PADDING_FRAME:
writer.WritePadding();
break;
case STREAM_FRAME:
if (!AppendStreamFramePayload(
*frame.stream_frame, last_frame_in_packet, &writer)) {
return kNoPacket;
}
break;
case ACK_FRAME:
if (!AppendAckFramePayload(*frame.ack_frame, &writer)) {
return kNoPacket;
}
break;
case CONGESTION_FEEDBACK_FRAME:
if (!AppendQuicCongestionFeedbackFramePayload(
*frame.congestion_feedback_frame, &writer)) {
return kNoPacket;
}
break;
case RST_STREAM_FRAME:
if (!AppendRstStreamFramePayload(*frame.rst_stream_frame, &writer)) {
return kNoPacket;
}
break;
case CONNECTION_CLOSE_FRAME:
if (!AppendConnectionCloseFramePayload(
*frame.connection_close_frame, &writer)) {
return kNoPacket;
}
break;
case GOAWAY_FRAME:
if (!AppendGoAwayFramePayload(*frame.goaway_frame, &writer)) {
return kNoPacket;
}
break;
default:
RaiseError(QUIC_INVALID_FRAME_DATA);
return kNoPacket;
}
}
// Save the length before writing, because take clears it.
const size_t len = writer.length();
// Less than or equal because truncated acks end up with max_plaintex_size
// length, even though they're typically slightly shorter.
DCHECK_LE(len, packet_size);
QuicPacket* packet = QuicPacket::NewDataPacket(
writer.take(), len, true, header.public_header.guid_length,
header.public_header.version_flag,
header.public_header.sequence_number_length);
if (fec_builder_) {
fec_builder_->OnBuiltFecProtectedPayload(header,
packet->FecProtectedData());
}
return SerializedPacket(header.packet_sequence_number,
header.public_header.sequence_number_length, packet,
GetPacketEntropyHash(header), NULL);
}
SerializedPacket QuicFramer::BuildFecPacket(const QuicPacketHeader& header,
const QuicFecData& fec) {
DCHECK_EQ(IN_FEC_GROUP, header.is_in_fec_group);
DCHECK_NE(0u, header.fec_group);
size_t len = GetPacketHeaderSize(header);
len += fec.redundancy.length();
QuicDataWriter writer(len);
const SerializedPacket kNoPacket(
0, PACKET_1BYTE_SEQUENCE_NUMBER, NULL, 0, NULL);
if (!WritePacketHeader(header, &writer)) {
return kNoPacket;
}
if (!writer.WriteBytes(fec.redundancy.data(), fec.redundancy.length())) {
return kNoPacket;
}
return SerializedPacket(
header.packet_sequence_number,
header.public_header.sequence_number_length,
QuicPacket::NewFecPacket(writer.take(), len, true,
header.public_header.guid_length,
header.public_header.version_flag,
header.public_header.sequence_number_length),
GetPacketEntropyHash(header), NULL);
}
// static
QuicEncryptedPacket* QuicFramer::BuildPublicResetPacket(
const QuicPublicResetPacket& packet) {
DCHECK(packet.public_header.reset_flag);
size_t len = GetPublicResetPacketSize();
QuicDataWriter writer(len);
uint8 flags = static_cast<uint8>(PACKET_PUBLIC_FLAGS_RST |
PACKET_PUBLIC_FLAGS_8BYTE_GUID |
PACKET_PUBLIC_FLAGS_6BYTE_SEQUENCE);
if (!writer.WriteUInt8(flags)) {
return NULL;
}
if (!writer.WriteUInt64(packet.public_header.guid)) {
return NULL;
}
if (!writer.WriteUInt64(packet.nonce_proof)) {
return NULL;
}
if (!AppendPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
packet.rejected_sequence_number,
&writer)) {
return NULL;
}
return new QuicEncryptedPacket(writer.take(), len, true);
}
QuicEncryptedPacket* QuicFramer::BuildVersionNegotiationPacket(
const QuicPacketPublicHeader& header,
const QuicVersionVector& supported_versions) {
DCHECK(header.version_flag);
size_t len = GetVersionNegotiationPacketSize(supported_versions.size());
QuicDataWriter writer(len);
uint8 flags = static_cast<uint8>(PACKET_PUBLIC_FLAGS_VERSION |
PACKET_PUBLIC_FLAGS_8BYTE_GUID |
PACKET_PUBLIC_FLAGS_6BYTE_SEQUENCE);
if (!writer.WriteUInt8(flags)) {
return NULL;
}
if (!writer.WriteUInt64(header.guid)) {
return NULL;
}
for (size_t i = 0; i < supported_versions.size(); ++i) {
if (!writer.WriteUInt32(QuicVersionToQuicTag(supported_versions[i]))) {
return NULL;
}
}
return new QuicEncryptedPacket(writer.take(), len, true);
}
bool QuicFramer::ProcessPacket(const QuicEncryptedPacket& packet) {
// TODO(satyamshekhar): Don't RaiseError (and close the connection) for
// invalid (unauthenticated) packets.
DCHECK(!reader_.get());
reader_.reset(new QuicDataReader(packet.data(), packet.length()));
visitor_->OnPacket();
// First parse the public header.
QuicPacketPublicHeader public_header;
if (!ProcessPublicHeader(&public_header)) {
DLOG(WARNING) << "Unable to process public header.";
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (is_server_ && public_header.version_flag &&
public_header.versions[0] != quic_version_) {
if (!visitor_->OnProtocolVersionMismatch(public_header.versions[0])) {
reader_.reset(NULL);
return true;
}
}
bool rv;
if (!is_server_ && public_header.version_flag) {
rv = ProcessVersionNegotiationPacket(&public_header);
} else if (public_header.reset_flag) {
rv = ProcessPublicResetPacket(public_header);
} else {
rv = ProcessDataPacket(public_header, packet);
}
reader_.reset(NULL);
return rv;
}
bool QuicFramer::ProcessVersionNegotiationPacket(
QuicPacketPublicHeader* public_header) {
DCHECK(!is_server_);
// Try reading at least once to raise error if the packet is invalid.
do {
QuicTag version;
if (!reader_->ReadBytes(&version, kQuicVersionSize)) {
set_detailed_error("Unable to read supported version in negotiation.");
return RaiseError(QUIC_INVALID_VERSION_NEGOTIATION_PACKET);
}
public_header->versions.push_back(QuicTagToQuicVersion(version));
} while (!reader_->IsDoneReading());
visitor_->OnVersionNegotiationPacket(*public_header);
return true;
}
bool QuicFramer::ProcessDataPacket(
const QuicPacketPublicHeader& public_header,
const QuicEncryptedPacket& packet) {
QuicPacketHeader header(public_header);
if (!ProcessPacketHeader(&header, packet)) {
DCHECK_NE(QUIC_NO_ERROR, error_); // ProcessPacketHeader sets the error.
DLOG(WARNING) << "Unable to process data packet header.";
return false;
}
if (!visitor_->OnPacketHeader(header)) {
// The visitor suppresses further processing of the packet.
return true;
}
if (packet.length() > kMaxPacketSize) {
DLOG(WARNING) << "Packet too large: " << packet.length();
return RaiseError(QUIC_PACKET_TOO_LARGE);
}
// Handle the payload.
if (!header.fec_flag) {
if (header.is_in_fec_group == IN_FEC_GROUP) {
StringPiece payload = reader_->PeekRemainingPayload();
visitor_->OnFecProtectedPayload(payload);
}
if (!ProcessFrameData()) {
DCHECK_NE(QUIC_NO_ERROR, error_); // ProcessFrameData sets the error.
DLOG(WARNING) << "Unable to process frame data.";
return false;
}
} else {
QuicFecData fec_data;
fec_data.fec_group = header.fec_group;
fec_data.redundancy = reader_->ReadRemainingPayload();
visitor_->OnFecData(fec_data);
}
visitor_->OnPacketComplete();
return true;
}
bool QuicFramer::ProcessPublicResetPacket(
const QuicPacketPublicHeader& public_header) {
QuicPublicResetPacket packet(public_header);
if (!reader_->ReadUInt64(&packet.nonce_proof)) {
set_detailed_error("Unable to read nonce proof.");
return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET);
}
// TODO(satyamshekhar): validate nonce to protect against DoS.
if (!reader_->ReadUInt48(&packet.rejected_sequence_number)) {
set_detailed_error("Unable to read rejected sequence number.");
return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET);
}
visitor_->OnPublicResetPacket(packet);
return true;
}
bool QuicFramer::ProcessRevivedPacket(QuicPacketHeader* header,
StringPiece payload) {
DCHECK(!reader_.get());
visitor_->OnRevivedPacket();
header->entropy_hash = GetPacketEntropyHash(*header);
if (!visitor_->OnPacketHeader(*header)) {
return true;
}
if (payload.length() > kMaxPacketSize) {
set_detailed_error("Revived packet too large.");
return RaiseError(QUIC_PACKET_TOO_LARGE);
}
reader_.reset(new QuicDataReader(payload.data(), payload.length()));
if (!ProcessFrameData()) {
DCHECK_NE(QUIC_NO_ERROR, error_); // ProcessFrameData sets the error.
DLOG(WARNING) << "Unable to process frame data.";
return false;
}
visitor_->OnPacketComplete();
reader_.reset(NULL);
return true;
}
bool QuicFramer::WritePacketHeader(const QuicPacketHeader& header,
QuicDataWriter* writer) {
DCHECK(header.fec_group > 0 || header.is_in_fec_group == NOT_IN_FEC_GROUP);
uint8 public_flags = 0;
if (header.public_header.reset_flag) {
public_flags |= PACKET_PUBLIC_FLAGS_RST;
}
if (header.public_header.version_flag) {
public_flags |= PACKET_PUBLIC_FLAGS_VERSION;
}
switch (header.public_header.sequence_number_length) {
case PACKET_1BYTE_SEQUENCE_NUMBER:
public_flags |= PACKET_PUBLIC_FLAGS_1BYTE_SEQUENCE;
break;
case PACKET_2BYTE_SEQUENCE_NUMBER:
public_flags |= PACKET_PUBLIC_FLAGS_2BYTE_SEQUENCE;
break;
case PACKET_4BYTE_SEQUENCE_NUMBER:
public_flags |= PACKET_PUBLIC_FLAGS_4BYTE_SEQUENCE;
break;
case PACKET_6BYTE_SEQUENCE_NUMBER:
public_flags |= PACKET_PUBLIC_FLAGS_6BYTE_SEQUENCE;
break;
}
switch (header.public_header.guid_length) {
case PACKET_0BYTE_GUID:
if (!writer->WriteUInt8(public_flags | PACKET_PUBLIC_FLAGS_0BYTE_GUID)) {
return false;
}
break;
case PACKET_1BYTE_GUID:
if (!writer->WriteUInt8(public_flags | PACKET_PUBLIC_FLAGS_1BYTE_GUID)) {
return false;
}
if (!writer->WriteUInt8(header.public_header.guid & k1ByteGuidMask)) {
return false;
}
break;
case PACKET_4BYTE_GUID:
if (!writer->WriteUInt8(public_flags | PACKET_PUBLIC_FLAGS_4BYTE_GUID)) {
return false;
}
if (!writer->WriteUInt32(header.public_header.guid & k4ByteGuidMask)) {
return false;
}
break;
case PACKET_8BYTE_GUID:
if (!writer->WriteUInt8(public_flags | PACKET_PUBLIC_FLAGS_8BYTE_GUID)) {
return false;
}
if (!writer->WriteUInt64(header.public_header.guid)) {
return false;
}
break;
}
last_serialized_guid_ = header.public_header.guid;
if (header.public_header.version_flag) {
DCHECK(!is_server_);
writer->WriteUInt32(QuicVersionToQuicTag(quic_version_));
}
if (!AppendPacketSequenceNumber(header.public_header.sequence_number_length,
header.packet_sequence_number, writer)) {
return false;
}
uint8 private_flags = 0;
if (header.entropy_flag) {
private_flags |= PACKET_PRIVATE_FLAGS_ENTROPY;
}
if (header.is_in_fec_group == IN_FEC_GROUP) {
private_flags |= PACKET_PRIVATE_FLAGS_FEC_GROUP;
}
if (header.fec_flag) {
private_flags |= PACKET_PRIVATE_FLAGS_FEC;
}
if (!writer->WriteUInt8(private_flags)) {
return false;
}
// The FEC group number is the sequence number of the first fec
// protected packet, or 0 if this packet is not protected.
if (header.is_in_fec_group == IN_FEC_GROUP) {
DCHECK_GE(header.packet_sequence_number, header.fec_group);
DCHECK_GT(255u, header.packet_sequence_number - header.fec_group);
// Offset from the current packet sequence number to the first fec
// protected packet.
uint8 first_fec_protected_packet_offset =
header.packet_sequence_number - header.fec_group;
if (!writer->WriteBytes(&first_fec_protected_packet_offset, 1)) {
return false;
}
}
return true;
}
QuicPacketSequenceNumber QuicFramer::CalculatePacketSequenceNumberFromWire(
QuicSequenceNumberLength sequence_number_length,
QuicPacketSequenceNumber packet_sequence_number) const {
// The new sequence number might have wrapped to the next epoch, or
// it might have reverse wrapped to the previous epoch, or it might
// remain in the same epoch. Select the sequence number closest to the
// next expected sequence number, the previous sequence number plus 1.
// epoch_delta is the delta between epochs the sequence number was serialized
// with, so the correct value is likely the same epoch as the last sequence
// number or an adjacent epoch.
const QuicPacketSequenceNumber epoch_delta =
GG_UINT64_C(1) << (8 * sequence_number_length);
QuicPacketSequenceNumber next_sequence_number = last_sequence_number_ + 1;
QuicPacketSequenceNumber epoch = last_sequence_number_ & ~(epoch_delta - 1);
QuicPacketSequenceNumber prev_epoch = epoch - epoch_delta;
QuicPacketSequenceNumber next_epoch = epoch + epoch_delta;
return ClosestTo(next_sequence_number,
epoch + packet_sequence_number,
ClosestTo(next_sequence_number,
prev_epoch + packet_sequence_number,
next_epoch + packet_sequence_number));
}
bool QuicFramer::ProcessPublicHeader(
QuicPacketPublicHeader* public_header) {
uint8 public_flags;
if (!reader_->ReadBytes(&public_flags, 1)) {
set_detailed_error("Unable to read public flags.");
return false;
}
public_header->reset_flag = (public_flags & PACKET_PUBLIC_FLAGS_RST) != 0;
public_header->version_flag =
(public_flags & PACKET_PUBLIC_FLAGS_VERSION) != 0;
if (!public_header->version_flag && public_flags > PACKET_PUBLIC_FLAGS_MAX) {
set_detailed_error("Illegal public flags value.");
return false;
}
if (public_header->reset_flag && public_header->version_flag) {
set_detailed_error("Got version flag in reset packet");
return false;
}
switch (public_flags & PACKET_PUBLIC_FLAGS_8BYTE_GUID) {
case PACKET_PUBLIC_FLAGS_8BYTE_GUID:
if (!reader_->ReadUInt64(&public_header->guid)) {
set_detailed_error("Unable to read GUID.");
return false;
}
public_header->guid_length = PACKET_8BYTE_GUID;
break;
case PACKET_PUBLIC_FLAGS_4BYTE_GUID:
// If the guid is truncated, expect to read the last serialized guid.
if (!reader_->ReadBytes(&public_header->guid, PACKET_4BYTE_GUID)) {
set_detailed_error("Unable to read GUID.");
return false;
}
if ((public_header->guid & k4ByteGuidMask) !=
(last_serialized_guid_ & k4ByteGuidMask)) {
set_detailed_error(
"Truncated 4 byte GUID does not match previous guid.");
return false;
}
public_header->guid_length = PACKET_4BYTE_GUID;
public_header->guid = last_serialized_guid_;
break;
case PACKET_PUBLIC_FLAGS_1BYTE_GUID:
if (!reader_->ReadBytes(&public_header->guid, PACKET_1BYTE_GUID)) {
set_detailed_error("Unable to read GUID.");
return false;
}
if ((public_header->guid & k1ByteGuidMask) !=
(last_serialized_guid_ & k1ByteGuidMask)) {
set_detailed_error(
"Truncated 1 byte GUID does not match previous guid.");
return false;
}
public_header->guid_length = PACKET_1BYTE_GUID;
public_header->guid = last_serialized_guid_;
break;
case PACKET_PUBLIC_FLAGS_0BYTE_GUID:
public_header->guid_length = PACKET_0BYTE_GUID;
public_header->guid = last_serialized_guid_;
break;
}
switch (public_flags & PACKET_PUBLIC_FLAGS_6BYTE_SEQUENCE) {
case PACKET_PUBLIC_FLAGS_6BYTE_SEQUENCE:
public_header->sequence_number_length = PACKET_6BYTE_SEQUENCE_NUMBER;
break;
case PACKET_PUBLIC_FLAGS_4BYTE_SEQUENCE:
public_header->sequence_number_length = PACKET_4BYTE_SEQUENCE_NUMBER;
break;
case PACKET_PUBLIC_FLAGS_2BYTE_SEQUENCE:
public_header->sequence_number_length = PACKET_2BYTE_SEQUENCE_NUMBER;
break;
case PACKET_PUBLIC_FLAGS_1BYTE_SEQUENCE:
public_header->sequence_number_length = PACKET_1BYTE_SEQUENCE_NUMBER;
break;
}
// Read the version only if the packet is from the client.
// version flag from the server means version negotiation packet.
if (public_header->version_flag && is_server_) {
QuicTag version_tag;
if (!reader_->ReadUInt32(&version_tag)) {
set_detailed_error("Unable to read protocol version.");
return false;
}
// If the version from the new packet is the same as the version of this
// framer, then the public flags should be set to something we understand.
// If not, this raises an error.
QuicVersion version = QuicTagToQuicVersion(version_tag);
if (version == quic_version_ && public_flags > PACKET_PUBLIC_FLAGS_MAX) {
set_detailed_error("Illegal public flags value.");
return false;
}
public_header->versions.push_back(version);
}
return true;
}
// static
bool QuicFramer::ReadGuidFromPacket(const QuicEncryptedPacket& packet,
QuicGuid* guid) {
QuicDataReader reader(packet.data(), packet.length());
uint8 public_flags;
if (!reader.ReadBytes(&public_flags, 1)) {
return false;
}
// Ensure it's an 8 byte guid.
if ((public_flags & PACKET_PUBLIC_FLAGS_8BYTE_GUID) !=
PACKET_PUBLIC_FLAGS_8BYTE_GUID) {
return false;
}
return reader.ReadUInt64(guid);
}
bool QuicFramer::ProcessPacketHeader(
QuicPacketHeader* header,
const QuicEncryptedPacket& packet) {
if (!ProcessPacketSequenceNumber(header->public_header.sequence_number_length,
&header->packet_sequence_number)) {
set_detailed_error("Unable to read sequence number.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (header->packet_sequence_number == 0u) {
set_detailed_error("Packet sequence numbers cannot be 0.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (!DecryptPayload(*header, packet)) {
set_detailed_error("Unable to decrypt payload.");
return RaiseError(QUIC_DECRYPTION_FAILURE);
}
uint8 private_flags;
if (!reader_->ReadBytes(&private_flags, 1)) {
set_detailed_error("Unable to read private flags.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (private_flags > PACKET_PRIVATE_FLAGS_MAX) {
set_detailed_error("Illegal private flags value.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
header->entropy_flag = (private_flags & PACKET_PRIVATE_FLAGS_ENTROPY) != 0;
header->fec_flag = (private_flags & PACKET_PRIVATE_FLAGS_FEC) != 0;
if ((private_flags & PACKET_PRIVATE_FLAGS_FEC_GROUP) != 0) {
header->is_in_fec_group = IN_FEC_GROUP;
uint8 first_fec_protected_packet_offset;
if (!reader_->ReadBytes(&first_fec_protected_packet_offset, 1)) {
set_detailed_error("Unable to read first fec protected packet offset.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (first_fec_protected_packet_offset >= header->packet_sequence_number) {
set_detailed_error("First fec protected packet offset must be less "
"than the sequence number.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
header->fec_group =
header->packet_sequence_number - first_fec_protected_packet_offset;
}
header->entropy_hash = GetPacketEntropyHash(*header);
// Set the last sequence number after we have decrypted the packet
// so we are confident is not attacker controlled.
last_sequence_number_ = header->packet_sequence_number;
return true;
}
bool QuicFramer::ProcessPacketSequenceNumber(
QuicSequenceNumberLength sequence_number_length,
QuicPacketSequenceNumber* sequence_number) {
QuicPacketSequenceNumber wire_sequence_number = 0u;
if (!reader_->ReadBytes(&wire_sequence_number, sequence_number_length)) {
return false;
}
// TODO(ianswett): Explore the usefulness of trying multiple sequence numbers
// in case the first guess is incorrect.
*sequence_number =
CalculatePacketSequenceNumberFromWire(sequence_number_length,
wire_sequence_number);
return true;
}
bool QuicFramer::ProcessFrameData() {
if (reader_->IsDoneReading()) {
set_detailed_error("Packet has no frames.");
return RaiseError(QUIC_MISSING_PAYLOAD);
}
while (!reader_->IsDoneReading()) {
uint8 frame_type;
if (!reader_->ReadBytes(&frame_type, 1)) {
set_detailed_error("Unable to read frame type.");
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
if (frame_type & kQuicFrameTypeSpecialMask) {
// Stream Frame
if (frame_type & kQuicFrameTypeStreamMask) {
QuicStreamFrame frame;
if (!ProcessStreamFrame(frame_type, &frame)) {
return RaiseError(QUIC_INVALID_STREAM_DATA);
}
if (!visitor_->OnStreamFrame(frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
// Ack Frame
if (frame_type & kQuicFrameTypeAckMask) {
QuicAckFrame frame;
if (!ProcessAckFrame(&frame)) {
return RaiseError(QUIC_INVALID_ACK_DATA);
}
if (!visitor_->OnAckFrame(frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
// Congestion Feedback Frame
if (frame_type & kQuicFrameTypeCongestionFeedbackMask) {
QuicCongestionFeedbackFrame frame;
if (!ProcessQuicCongestionFeedbackFrame(&frame)) {
return RaiseError(QUIC_INVALID_CONGESTION_FEEDBACK_DATA);
}
if (!visitor_->OnCongestionFeedbackFrame(frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
// This was a special frame type that did not match any
// of the known ones. Error.
set_detailed_error("Illegal frame type.");
DLOG(WARNING) << "Illegal frame type: "
<< static_cast<int>(frame_type);
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
switch (frame_type) {
case PADDING_FRAME:
// We're done with the packet.
return true;
case RST_STREAM_FRAME: {
QuicRstStreamFrame frame;
if (!ProcessRstStreamFrame(&frame)) {
return RaiseError(QUIC_INVALID_RST_STREAM_DATA);
}
if (!visitor_->OnRstStreamFrame(frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case CONNECTION_CLOSE_FRAME: {
QuicConnectionCloseFrame frame;
if (!ProcessConnectionCloseFrame(&frame)) {
return RaiseError(QUIC_INVALID_CONNECTION_CLOSE_DATA);
}
if (!visitor_->OnAckFrame(frame.ack_frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
if (!visitor_->OnConnectionCloseFrame(frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case GOAWAY_FRAME: {
QuicGoAwayFrame goaway_frame;
if (!ProcessGoAwayFrame(&goaway_frame)) {
return RaiseError(QUIC_INVALID_GOAWAY_DATA);
}
if (!visitor_->OnGoAwayFrame(goaway_frame)) {
DLOG(INFO) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
default:
set_detailed_error("Illegal frame type.");
DLOG(WARNING) << "Illegal frame type: "
<< static_cast<int>(frame_type);
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
}
return true;
}
bool QuicFramer::ProcessStreamFrame(uint8 frame_type,
QuicStreamFrame* frame) {
uint8 stream_flags = frame_type;
stream_flags &= ~kQuicFrameTypeStreamMask;
// Read from right to left: StreamID, Offset, Data Length, Fin.
const uint8 stream_id_length = (stream_flags & kQuicStreamIDLengthMask) + 1;
stream_flags >>= kQuicStreamIdShift;
uint8 offset_length = (stream_flags & kQuicStreamOffsetMask);
// There is no encoding for 1 byte, only 0 and 2 through 8.
if (offset_length > 0) {
offset_length += 1;
}
stream_flags >>= kQuicStreamOffsetShift;
bool has_data_length =
(stream_flags & kQuicStreamDataLengthMask) == kQuicStreamDataLengthMask;
stream_flags >>= kQuicStreamDataLengthShift;
frame->fin = (stream_flags & kQuicStreamFinMask) == kQuicStreamFinShift;
frame->stream_id = 0;
if (!reader_->ReadBytes(&frame->stream_id, stream_id_length)) {
set_detailed_error("Unable to read stream_id.");
return false;
}
frame->offset = 0;
if (!reader_->ReadBytes(&frame->offset, offset_length)) {
set_detailed_error("Unable to read offset.");
return false;
}
if (has_data_length) {
if (!reader_->ReadStringPiece16(&frame->data)) {
set_detailed_error("Unable to read frame data.");
return false;
}
} else {
if (!reader_->ReadStringPiece(&frame->data, reader_->BytesRemaining())) {
set_detailed_error("Unable to read frame data.");
return false;
}
}
return true;
}
bool QuicFramer::ProcessAckFrame(QuicAckFrame* frame) {
if (!ProcessSentInfo(&frame->sent_info)) {
return false;
}
if (!ProcessReceivedInfo(&frame->received_info)) {
return false;
}
return true;
}
bool QuicFramer::ProcessReceivedInfo(ReceivedPacketInfo* received_info) {
if (!reader_->ReadBytes(&received_info->entropy_hash, 1)) {
set_detailed_error("Unable to read entropy hash for received packets.");
return false;
}
if (!ProcessPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
&received_info->largest_observed)) {
set_detailed_error("Unable to read largest observed.");
return false;
}
uint32 delta_time_largest_observed_us;
if (!reader_->ReadUInt32(&delta_time_largest_observed_us)) {
set_detailed_error("Unable to read delta time largest observed.");
return false;
}
if (delta_time_largest_observed_us == kInvalidDeltaTime) {
received_info->delta_time_largest_observed = QuicTime::Delta::Infinite();
} else {
received_info->delta_time_largest_observed =
QuicTime::Delta::FromMicroseconds(delta_time_largest_observed_us);
}
uint8 num_missing_packets;
if (!reader_->ReadBytes(&num_missing_packets, 1)) {
set_detailed_error("Unable to read num missing packets.");
return false;
}
for (int i = 0; i < num_missing_packets; ++i) {
QuicPacketSequenceNumber sequence_number;
if (!ProcessPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
&sequence_number)) {
set_detailed_error("Unable to read sequence number in missing packets.");
return false;
}
received_info->missing_packets.insert(sequence_number);
}
return true;
}
bool QuicFramer::ProcessSentInfo(SentPacketInfo* sent_info) {
if (!reader_->ReadBytes(&sent_info->entropy_hash, 1)) {
set_detailed_error("Unable to read entropy hash for sent packets.");
return false;
}
if (!ProcessPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
&sent_info->least_unacked)) {
set_detailed_error("Unable to read least unacked.");
return false;
}
return true;
}
bool QuicFramer::ProcessQuicCongestionFeedbackFrame(
QuicCongestionFeedbackFrame* frame) {
uint8 feedback_type;
if (!reader_->ReadBytes(&feedback_type, 1)) {
set_detailed_error("Unable to read congestion feedback type.");
return false;
}
frame->type =
static_cast<CongestionFeedbackType>(feedback_type);
switch (frame->type) {
case kInterArrival: {
CongestionFeedbackMessageInterArrival* inter_arrival =
&frame->inter_arrival;
if (!reader_->ReadUInt16(
&inter_arrival->accumulated_number_of_lost_packets)) {
set_detailed_error(
"Unable to read accumulated number of lost packets.");
return false;
}
uint8 num_received_packets;
if (!reader_->ReadBytes(&num_received_packets, 1)) {
set_detailed_error("Unable to read num received packets.");
return false;
}
if (num_received_packets > 0u) {
uint64 smallest_received;
if (!ProcessPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
&smallest_received)) {
set_detailed_error("Unable to read smallest received.");
return false;
}
uint64 time_received_us;
if (!reader_->ReadUInt64(&time_received_us)) {
set_detailed_error("Unable to read time received.");
return false;
}
QuicTime time_received = creation_time_.Add(
QuicTime::Delta::FromMicroseconds(time_received_us));
inter_arrival->received_packet_times.insert(
make_pair(smallest_received, time_received));
for (int i = 0; i < num_received_packets - 1; ++i) {
uint16 sequence_delta;
if (!reader_->ReadUInt16(&sequence_delta)) {
set_detailed_error(
"Unable to read sequence delta in received packets.");
return false;
}
int32 time_delta_us;
if (!reader_->ReadBytes(&time_delta_us, sizeof(time_delta_us))) {
set_detailed_error(
"Unable to read time delta in received packets.");
return false;
}
QuicPacketSequenceNumber packet = smallest_received + sequence_delta;
inter_arrival->received_packet_times.insert(
make_pair(packet, time_received.Add(
QuicTime::Delta::FromMicroseconds(time_delta_us))));
}
}
break;
}
case kFixRate: {
uint32 bitrate = 0;
if (!reader_->ReadUInt32(&bitrate)) {
set_detailed_error("Unable to read bitrate.");
return false;
}
frame->fix_rate.bitrate = QuicBandwidth::FromBytesPerSecond(bitrate);
break;
}
case kTCP: {
CongestionFeedbackMessageTCP* tcp = &frame->tcp;
if (!reader_->ReadUInt16(&tcp->accumulated_number_of_lost_packets)) {
set_detailed_error(
"Unable to read accumulated number of lost packets.");
return false;
}
uint16 receive_window = 0;
if (!reader_->ReadUInt16(&receive_window)) {
set_detailed_error("Unable to read receive window.");
return false;
}
// Simple bit packing, don't send the 4 least significant bits.
tcp->receive_window = static_cast<QuicByteCount>(receive_window) << 4;
break;
}
default:
set_detailed_error("Illegal congestion feedback type.");
DLOG(WARNING) << "Illegal congestion feedback type: "
<< frame->type;
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
return true;
}
bool QuicFramer::ProcessRstStreamFrame(QuicRstStreamFrame* frame) {
if (!reader_->ReadUInt32(&frame->stream_id)) {
set_detailed_error("Unable to read stream_id.");
return false;
}
uint32 error_code;
if (!reader_->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read rst stream error code.");
return false;
}
if (error_code >= QUIC_STREAM_LAST_ERROR ||
error_code < QUIC_STREAM_NO_ERROR) {
set_detailed_error("Invalid rst stream error code.");
return false;
}
frame->error_code = static_cast<QuicRstStreamErrorCode>(error_code);
StringPiece error_details;
if (!reader_->ReadStringPiece16(&error_details)) {
set_detailed_error("Unable to read rst stream error details.");
return false;
}
frame->error_details = error_details.as_string();
return true;
}
bool QuicFramer::ProcessConnectionCloseFrame(QuicConnectionCloseFrame* frame) {
uint32 error_code;
if (!reader_->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read connection close error code.");
return false;
}
if (error_code >= QUIC_LAST_ERROR ||
error_code < QUIC_NO_ERROR) {
set_detailed_error("Invalid error code.");
return false;
}
frame->error_code = static_cast<QuicErrorCode>(error_code);
StringPiece error_details;
if (!reader_->ReadStringPiece16(&error_details)) {
set_detailed_error("Unable to read connection close error details.");
return false;
}
frame->error_details = error_details.as_string();
if (!ProcessAckFrame(&frame->ack_frame)) {
DLOG(WARNING) << "Unable to process ack frame.";
return false;
}
return true;
}
bool QuicFramer::ProcessGoAwayFrame(QuicGoAwayFrame* frame) {
uint32 error_code;
if (!reader_->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read go away error code.");
return false;
}
frame->error_code = static_cast<QuicErrorCode>(error_code);
if (error_code >= QUIC_LAST_ERROR ||
error_code < QUIC_NO_ERROR) {
set_detailed_error("Invalid error code.");
return false;
}
uint32 stream_id;
if (!reader_->ReadUInt32(&stream_id)) {
set_detailed_error("Unable to read last good stream id.");
return false;
}
frame->last_good_stream_id = static_cast<QuicStreamId>(stream_id);
StringPiece reason_phrase;
if (!reader_->ReadStringPiece16(&reason_phrase)) {
set_detailed_error("Unable to read goaway reason.");
return false;
}
frame->reason_phrase = reason_phrase.as_string();
return true;
}
// static
StringPiece QuicFramer::GetAssociatedDataFromEncryptedPacket(
const QuicEncryptedPacket& encrypted,
QuicGuidLength guid_length,
bool includes_version,
QuicSequenceNumberLength sequence_number_length) {
return StringPiece(encrypted.data() + kStartOfHashData,
GetStartOfEncryptedData(
guid_length, includes_version, sequence_number_length)
- kStartOfHashData);
}
void QuicFramer::SetDecrypter(QuicDecrypter* decrypter) {
DCHECK(alternative_decrypter_.get() == NULL);
decrypter_.reset(decrypter);
}
void QuicFramer::SetAlternativeDecrypter(QuicDecrypter* decrypter,
bool latch_once_used) {
alternative_decrypter_.reset(decrypter);
alternative_decrypter_latch_ = latch_once_used;
}
const QuicDecrypter* QuicFramer::decrypter() const {
return decrypter_.get();
}
const QuicDecrypter* QuicFramer::alternative_decrypter() const {
return alternative_decrypter_.get();
}
void QuicFramer::SetEncrypter(EncryptionLevel level,
QuicEncrypter* encrypter) {
DCHECK_GE(level, 0);
DCHECK_LT(level, NUM_ENCRYPTION_LEVELS);
encrypter_[level].reset(encrypter);
}
const QuicEncrypter* QuicFramer::encrypter(EncryptionLevel level) const {
DCHECK_GE(level, 0);
DCHECK_LT(level, NUM_ENCRYPTION_LEVELS);
DCHECK(encrypter_[level].get() != NULL);
return encrypter_[level].get();
}
void QuicFramer::SwapCryptersForTest(QuicFramer* other) {
for (int i = ENCRYPTION_NONE; i < NUM_ENCRYPTION_LEVELS; i++) {
encrypter_[i].swap(other->encrypter_[i]);
}
decrypter_.swap(other->decrypter_);
alternative_decrypter_.swap(other->alternative_decrypter_);
const bool other_latch = other->alternative_decrypter_latch_;
other->alternative_decrypter_latch_ = alternative_decrypter_latch_;
alternative_decrypter_latch_ = other_latch;
}
QuicEncryptedPacket* QuicFramer::EncryptPacket(
EncryptionLevel level,
QuicPacketSequenceNumber packet_sequence_number,
const QuicPacket& packet) {
DCHECK(encrypter_[level].get() != NULL);
scoped_ptr<QuicData> out(encrypter_[level]->EncryptPacket(
packet_sequence_number, packet.AssociatedData(), packet.Plaintext()));
if (out.get() == NULL) {
RaiseError(QUIC_ENCRYPTION_FAILURE);
return NULL;
}
StringPiece header_data = packet.BeforePlaintext();
size_t len = header_data.length() + out->length();
char* buffer = new char[len];
// TODO(rch): eliminate this buffer copy by passing in a buffer to Encrypt().
memcpy(buffer, header_data.data(), header_data.length());
memcpy(buffer + header_data.length(), out->data(), out->length());
return new QuicEncryptedPacket(buffer, len, true);
}
size_t QuicFramer::GetMaxPlaintextSize(size_t ciphertext_size) {
// In order to keep the code simple, we don't have the current encryption
// level to hand. At the moment, the NullEncrypter has a tag length of 16
// bytes and AES-GCM has a tag length of 12. We take the minimum plaintext
// length just to be safe.
// TODO(rtenneti): remove '- 16' after we delete QUIC_VERSION_10.
size_t min_plaintext_size = ciphertext_size - 16;
for (int i = ENCRYPTION_NONE; i < NUM_ENCRYPTION_LEVELS; i++) {
if (encrypter_[i].get() != NULL) {
size_t size = encrypter_[i]->GetMaxPlaintextSize(ciphertext_size);
if (size < min_plaintext_size) {
min_plaintext_size = size;
}
}
}
return min_plaintext_size;
}
bool QuicFramer::DecryptPayload(const QuicPacketHeader& header,
const QuicEncryptedPacket& packet) {
StringPiece encrypted;
if (!reader_->ReadStringPiece(&encrypted, reader_->BytesRemaining())) {
return false;
}
DCHECK(decrypter_.get() != NULL);
decrypted_.reset(decrypter_->DecryptPacket(
header.packet_sequence_number,
GetAssociatedDataFromEncryptedPacket(
packet,
header.public_header.guid_length,
header.public_header.version_flag,
header.public_header.sequence_number_length),
encrypted));
if (decrypted_.get() == NULL && alternative_decrypter_.get() != NULL) {
decrypted_.reset(alternative_decrypter_->DecryptPacket(
header.packet_sequence_number,
GetAssociatedDataFromEncryptedPacket(
packet,
header.public_header.guid_length,
header.public_header.version_flag,
header.public_header.sequence_number_length),
encrypted));
if (decrypted_.get() != NULL) {
if (alternative_decrypter_latch_) {
// Switch to the alternative decrypter and latch so that we cannot
// switch back.
decrypter_.reset(alternative_decrypter_.release());
} else {
// Switch the alternative decrypter so that we use it first next time.
decrypter_.swap(alternative_decrypter_);
}
}
}
if (decrypted_.get() == NULL) {
return false;
}
reader_.reset(new QuicDataReader(decrypted_->data(), decrypted_->length()));
return true;
}
size_t QuicFramer::ComputeFrameLength(const QuicFrame& frame,
bool last_frame_in_packet) {
switch (frame.type) {
case STREAM_FRAME:
return GetMinStreamFrameSize(quic_version_,
frame.stream_frame->stream_id,
frame.stream_frame->offset,
last_frame_in_packet) +
frame.stream_frame->data.size();
case ACK_FRAME: {
const QuicAckFrame& ack = *frame.ack_frame;
return GetMinAckFrameSize() + PACKET_6BYTE_SEQUENCE_NUMBER *
ack.received_info.missing_packets.size();
}
case CONGESTION_FEEDBACK_FRAME: {
size_t len = kQuicFrameTypeSize;
const QuicCongestionFeedbackFrame& congestion_feedback =
*frame.congestion_feedback_frame;
len += 1; // Congestion feedback type.
switch (congestion_feedback.type) {
case kInterArrival: {
const CongestionFeedbackMessageInterArrival& inter_arrival =
congestion_feedback.inter_arrival;
len += 2;
len += 1; // Number received packets.
if (inter_arrival.received_packet_times.size() > 0) {
len += PACKET_6BYTE_SEQUENCE_NUMBER; // Smallest received.
len += 8; // Time.
// 2 bytes per sequence number delta plus 4 bytes per delta time.
len += PACKET_6BYTE_SEQUENCE_NUMBER *
(inter_arrival.received_packet_times.size() - 1);
}
break;
}
case kFixRate:
len += 4;
break;
case kTCP:
len += 4;
break;
default:
set_detailed_error("Illegal feedback type.");
DLOG(INFO) << "Illegal feedback type: " << congestion_feedback.type;
break;
}
return len;
}
case RST_STREAM_FRAME:
return GetMinRstStreamFrameSize() +
frame.rst_stream_frame->error_details.size();
case CONNECTION_CLOSE_FRAME: {
const QuicAckFrame& ack = frame.connection_close_frame->ack_frame;
return GetMinConnectionCloseFrameSize() +
frame.connection_close_frame->error_details.size() +
PACKET_6BYTE_SEQUENCE_NUMBER *
ack.received_info.missing_packets.size();
}
case GOAWAY_FRAME:
return GetMinGoAwayFrameSize() + frame.goaway_frame->reason_phrase.size();
case PADDING_FRAME:
DCHECK(false);
return 0;
case NUM_FRAME_TYPES:
DCHECK(false);
return 0;
}
// Not reachable, but some Chrome compilers can't figure that out. *sigh*
DCHECK(false);
return 0;
}
bool QuicFramer::AppendTypeByte(const QuicFrame& frame,
bool last_frame_in_packet,
QuicDataWriter* writer) {
uint8 type_byte = 0;
switch (frame.type) {
case STREAM_FRAME: {
if (frame.stream_frame == NULL) {
LOG(DFATAL) << "Failed to append STREAM frame with no stream_frame.";
}
// Fin bit.
type_byte |= frame.stream_frame->fin ? kQuicStreamFinMask : 0;
// Data Length bit.
type_byte <<= kQuicStreamDataLengthShift;
type_byte |= last_frame_in_packet ? 0 : kQuicStreamDataLengthMask;
// Offset 3 bits.
type_byte <<= kQuicStreamOffsetShift;
const size_t offset_len = GetStreamOffsetSize(frame.stream_frame->offset);
if (offset_len > 0) {
type_byte |= offset_len - 1;
}
// stream id 2 bits.
type_byte <<= kQuicStreamIdShift;
type_byte |= GetStreamIdSize(frame.stream_frame->stream_id) - 1;
type_byte |= kQuicFrameTypeStreamMask; // Set Stream Frame Type to 1.
break;
}
case ACK_FRAME: {
// TODO(ianswett): Use extra 5 bits in the ack framing.
type_byte = kQuicFrameTypeAckMask;
break;
}
case CONGESTION_FEEDBACK_FRAME: {
// TODO(ianswett): Use extra 5 bits in the congestion feedback framing.
type_byte = kQuicFrameTypeCongestionFeedbackMask;
break;
}
default:
type_byte = frame.type;
break;
}
return writer->WriteUInt8(type_byte);
}
// static
bool QuicFramer::AppendPacketSequenceNumber(
QuicSequenceNumberLength sequence_number_length,
QuicPacketSequenceNumber packet_sequence_number,
QuicDataWriter* writer) {
// Ensure the entire sequence number can be written.
if (writer->capacity() - writer->length() <
static_cast<size_t>(sequence_number_length)) {
return false;
}
switch (sequence_number_length) {
case PACKET_1BYTE_SEQUENCE_NUMBER:
return writer->WriteUInt8(
packet_sequence_number & k1ByteSequenceNumberMask);
break;
case PACKET_2BYTE_SEQUENCE_NUMBER:
return writer->WriteUInt16(
packet_sequence_number & k2ByteSequenceNumberMask);
break;
case PACKET_4BYTE_SEQUENCE_NUMBER:
return writer->WriteUInt32(
packet_sequence_number & k4ByteSequenceNumberMask);
break;
case PACKET_6BYTE_SEQUENCE_NUMBER:
return writer->WriteUInt48(
packet_sequence_number & k6ByteSequenceNumberMask);
break;
default:
NOTREACHED() << "sequence_number_length: " << sequence_number_length;
return false;
}
}
bool QuicFramer::AppendStreamFramePayload(
const QuicStreamFrame& frame,
bool last_frame_in_packet,
QuicDataWriter* writer) {
if (!writer->WriteBytes(&frame.stream_id, GetStreamIdSize(frame.stream_id))) {
return false;
}
if (!writer->WriteBytes(&frame.offset, GetStreamOffsetSize(frame.offset))) {
return false;
}
if (!last_frame_in_packet) {
if (!writer->WriteUInt16(frame.data.size())) {
return false;
}
}
if (!writer->WriteBytes(frame.data.data(), frame.data.size())) {
return false;
}
return true;
}
QuicPacketSequenceNumber QuicFramer::CalculateLargestObserved(
const SequenceNumberSet& missing_packets,
SequenceNumberSet::const_iterator largest_written) {
SequenceNumberSet::const_iterator it = largest_written;
QuicPacketSequenceNumber previous_missing = *it;
++it;
// See if the next thing is a gap in the missing packets: if it's a
// non-missing packet we can return it.
if (it != missing_packets.end() && previous_missing + 1 != *it) {
return *it - 1;
}
// Otherwise return the largest missing packet, as indirectly observed.
return *largest_written;
}
void QuicFramer::set_version(const QuicVersion version) {
DCHECK(IsSupportedVersion(version));
// Handle version incompatibility between QUIC_VERSION_10 and QUIC_VERSION_11
// because of introduction of a new QUIC null encryption format in
// QUIC_VERSION_11.
if ((quic_version_ > QUIC_VERSION_10 && version <= QUIC_VERSION_10) ||
(quic_version_ <= QUIC_VERSION_10 && version > QUIC_VERSION_10)) {
// TODO(rtenneti): remove the following code after we delete
// QUIC_VERSION_10.
decrypter_.reset(QuicDecrypter::Create(GetNullTag(version)));
encrypter_[ENCRYPTION_NONE].reset(
QuicEncrypter::Create(GetNullTag(version)));
}
quic_version_ = version;
}
// TODO(ianswett): Use varints or another more compact approach for all deltas.
bool QuicFramer::AppendAckFramePayload(
const QuicAckFrame& frame,
QuicDataWriter* writer) {
// TODO(satyamshekhar): Decide how often we really should send this
// entropy_hash update.
if (!writer->WriteUInt8(frame.sent_info.entropy_hash)) {
return false;
}
if (!AppendPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
frame.sent_info.least_unacked, writer)) {
return false;
}
size_t received_entropy_offset = writer->length();
if (!writer->WriteUInt8(frame.received_info.entropy_hash)) {
return false;
}
size_t largest_observed_offset = writer->length();
if (!AppendPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
frame.received_info.largest_observed,
writer)) {
return false;
}
uint32 delta_time_largest_observed_us = kInvalidDeltaTime;
if (!frame.received_info.delta_time_largest_observed.IsInfinite()) {
delta_time_largest_observed_us =
frame.received_info.delta_time_largest_observed.ToMicroseconds();
}
size_t delta_time_largest_observed_offset = writer->length();
if (!writer->WriteUInt32(delta_time_largest_observed_us)) {
return false;
}
// We don't check for overflowing uint8 here, because we only can fit 192 acks
// per packet, so if we overflow we will be truncated.
uint8 num_missing_packets = frame.received_info.missing_packets.size();
size_t num_missing_packets_offset = writer->length();
if (!writer->WriteBytes(&num_missing_packets, 1)) {
return false;
}
SequenceNumberSet::const_iterator it =
frame.received_info.missing_packets.begin();
int num_missing_packets_written = 0;
for (; it != frame.received_info.missing_packets.end(); ++it) {
if (!AppendPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
*it, writer)) {
// We are truncating.
QuicPacketSequenceNumber largest_observed =
CalculateLargestObserved(frame.received_info.missing_packets, --it);
// Overwrite entropy hash for received packets.
writer->WriteUInt8ToOffset(
entropy_calculator_->EntropyHash(largest_observed),
received_entropy_offset);
// Overwrite largest_observed.
writer->WriteUInt48ToOffset(largest_observed & k6ByteSequenceNumberMask,
largest_observed_offset);
writer->WriteUInt32ToOffset(kInvalidDeltaTime,
delta_time_largest_observed_offset);
writer->WriteUInt8ToOffset(num_missing_packets_written,
num_missing_packets_offset);
return true;
}
++num_missing_packets_written;
DCHECK_GE(numeric_limits<uint8>::max(), num_missing_packets_written);
}
return true;
}
bool QuicFramer::AppendQuicCongestionFeedbackFramePayload(
const QuicCongestionFeedbackFrame& frame,
QuicDataWriter* writer) {
if (!writer->WriteBytes(&frame.type, 1)) {
return false;
}
switch (frame.type) {
case kInterArrival: {
const CongestionFeedbackMessageInterArrival& inter_arrival =
frame.inter_arrival;
if (!writer->WriteUInt16(
inter_arrival.accumulated_number_of_lost_packets)) {
return false;
}
DCHECK_GE(numeric_limits<uint8>::max(),
inter_arrival.received_packet_times.size());
if (inter_arrival.received_packet_times.size() >
numeric_limits<uint8>::max()) {
return false;
}
// TODO(ianswett): Make num_received_packets a varint.
uint8 num_received_packets =
inter_arrival.received_packet_times.size();
if (!writer->WriteBytes(&num_received_packets, 1)) {
return false;
}
if (num_received_packets > 0) {
TimeMap::const_iterator it =
inter_arrival.received_packet_times.begin();
QuicPacketSequenceNumber lowest_sequence = it->first;
if (!AppendPacketSequenceNumber(PACKET_6BYTE_SEQUENCE_NUMBER,
lowest_sequence, writer)) {
return false;
}
QuicTime lowest_time = it->second;
if (!writer->WriteUInt64(
lowest_time.Subtract(creation_time_).ToMicroseconds())) {
return false;
}
for (++it; it != inter_arrival.received_packet_times.end(); ++it) {
QuicPacketSequenceNumber sequence_delta = it->first - lowest_sequence;
DCHECK_GE(numeric_limits<uint16>::max(), sequence_delta);
if (sequence_delta > numeric_limits<uint16>::max()) {
return false;
}
if (!writer->WriteUInt16(static_cast<uint16>(sequence_delta))) {
return false;
}
int32 time_delta_us =
it->second.Subtract(lowest_time).ToMicroseconds();
if (!writer->WriteBytes(&time_delta_us, sizeof(time_delta_us))) {
return false;
}
}
}
break;
}
case kFixRate: {
const CongestionFeedbackMessageFixRate& fix_rate =
frame.fix_rate;
if (!writer->WriteUInt32(fix_rate.bitrate.ToBytesPerSecond())) {
return false;
}
break;
}
case kTCP: {
const CongestionFeedbackMessageTCP& tcp = frame.tcp;
DCHECK_LE(tcp.receive_window, 1u << 20);
// Simple bit packing, don't send the 4 least significant bits.
uint16 receive_window = static_cast<uint16>(tcp.receive_window >> 4);
if (!writer->WriteUInt16(tcp.accumulated_number_of_lost_packets)) {
return false;
}
if (!writer->WriteUInt16(receive_window)) {
return false;
}
break;
}
default:
return false;
}
return true;
}
bool QuicFramer::AppendRstStreamFramePayload(
const QuicRstStreamFrame& frame,
QuicDataWriter* writer) {
if (!writer->WriteUInt32(frame.stream_id)) {
return false;
}
uint32 error_code = static_cast<uint32>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
if (!writer->WriteStringPiece16(frame.error_details)) {
return false;
}
return true;
}
bool QuicFramer::AppendConnectionCloseFramePayload(
const QuicConnectionCloseFrame& frame,
QuicDataWriter* writer) {
uint32 error_code = static_cast<uint32>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
if (!writer->WriteStringPiece16(frame.error_details)) {
return false;
}
AppendAckFramePayload(frame.ack_frame, writer);
return true;
}
bool QuicFramer::AppendGoAwayFramePayload(const QuicGoAwayFrame& frame,
QuicDataWriter* writer) {
uint32 error_code = static_cast<uint32>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
uint32 stream_id = static_cast<uint32>(frame.last_good_stream_id);
if (!writer->WriteUInt32(stream_id)) {
return false;
}
if (!writer->WriteStringPiece16(frame.reason_phrase)) {
return false;
}
return true;
}
bool QuicFramer::RaiseError(QuicErrorCode error) {
DLOG(INFO) << detailed_error_;
set_error(error);
visitor_->OnError(this);
reader_.reset(NULL);
return false;
}
} // namespace net