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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/core/quic_framer.h"
#include <cstdint>
#include <memory>
#include "base/compiler_specific.h"
#include "net/quic/core/crypto/crypto_framer.h"
#include "net/quic/core/crypto/crypto_handshake_message.h"
#include "net/quic/core/crypto/crypto_protocol.h"
#include "net/quic/core/crypto/null_decrypter.h"
#include "net/quic/core/crypto/null_encrypter.h"
#include "net/quic/core/crypto/quic_decrypter.h"
#include "net/quic/core/crypto/quic_encrypter.h"
#include "net/quic/core/quic_data_reader.h"
#include "net/quic/core/quic_data_writer.h"
#include "net/quic/core/quic_flags.h"
#include "net/quic/core/quic_socket_address_coder.h"
#include "net/quic/core/quic_utils.h"
#include "net/quic/platform/api/quic_aligned.h"
#include "net/quic/platform/api/quic_bug_tracker.h"
#include "net/quic/platform/api/quic_logging.h"
#include "net/quic/platform/api/quic_map_util.h"
#include "net/quic/platform/api/quic_ptr_util.h"
using std::string;
namespace net {
namespace {
#define ENDPOINT \
(perspective_ == Perspective::IS_SERVER ? "Server: " : "Client: ")
// Mask to select the lowest 48 bits of a packet number.
const QuicPacketNumber k6ByteSequenceNumberMask = UINT64_C(0x0000FFFFFFFFFFFF);
const QuicPacketNumber k4ByteSequenceNumberMask = UINT64_C(0x00000000FFFFFFFF);
const QuicPacketNumber k2ByteSequenceNumberMask = UINT64_C(0x000000000000FFFF);
const QuicPacketNumber k1ByteSequenceNumberMask = UINT64_C(0x00000000000000FF);
// Number of bits the packet number length bits are shifted from the right
// edge of the public header.
const uint8_t kPublicHeaderSequenceNumberShift = 4;
// 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)
// WindowUpdate : 0b 00000100 (0x04)
// Blocked : 0b 00000101 (0x05)
//
// Special Frame Types encode both a Frame Type and corresponding flags
// all in the Frame Type byte. Currently defined Special Frame Types are:
// Stream : 0b 1xxxxxxx
// Ack : 0b 01xxxxxx
//
// Semantics of the flag bits above (the x bits) depends on the frame type.
// Masks to determine if the frame type is a special use
// and for specific special frame types.
const uint8_t kQuicFrameTypeSpecialMask = 0xE0; // 0b 11100000
const uint8_t kQuicFrameTypeStreamMask = 0x80;
const uint8_t kQuicFrameTypeAckMask = 0x40;
// Stream frame relative shifts and masks for interpreting the stream flags.
// StreamID may be 1, 2, 3, or 4 bytes.
const uint8_t kQuicStreamIdShift = 2;
const uint8_t kQuicStreamIDLengthMask = 0x03;
// Offset may be 0, 2, 3, 4, 5, 6, 7, 8 bytes.
const uint8_t kQuicStreamOffsetShift = 3;
const uint8_t kQuicStreamOffsetMask = 0x07;
// Data length may be 0 or 2 bytes.
const uint8_t kQuicStreamDataLengthShift = 1;
const uint8_t kQuicStreamDataLengthMask = 0x01;
// Fin bit may be set or not.
const uint8_t kQuicStreamFinShift = 1;
const uint8_t kQuicStreamFinMask = 0x01;
// packet number size shift used in AckFrames.
const uint8_t kQuicSequenceNumberLengthShift = 2;
// Acks may have only one ack block.
const uint8_t kQuicHasMultipleAckBlocksMask = 0x01;
const uint8_t kQuicHasMultipleAckBlocksShift = 1;
// Returns the absolute value of the difference between |a| and |b|.
QuicPacketNumber Delta(QuicPacketNumber a, QuicPacketNumber b) {
// Since these are unsigned numbers, we can't just return abs(a - b)
if (a < b) {
return b - a;
}
return a - b;
}
QuicPacketNumber ClosestTo(QuicPacketNumber target,
QuicPacketNumber a,
QuicPacketNumber b) {
return (Delta(target, a) < Delta(target, b)) ? a : b;
}
QuicPacketNumberLength ReadSequenceNumberLength(uint8_t flags) {
switch (flags & PACKET_FLAGS_6BYTE_PACKET) {
case PACKET_FLAGS_6BYTE_PACKET:
return PACKET_6BYTE_PACKET_NUMBER;
case PACKET_FLAGS_4BYTE_PACKET:
return PACKET_4BYTE_PACKET_NUMBER;
case PACKET_FLAGS_2BYTE_PACKET:
return PACKET_2BYTE_PACKET_NUMBER;
case PACKET_FLAGS_1BYTE_PACKET:
return PACKET_1BYTE_PACKET_NUMBER;
default:
QUIC_BUG << "Unreachable case statement.";
return PACKET_6BYTE_PACKET_NUMBER;
}
}
} // namespace
QuicFramer::QuicFramer(const QuicVersionVector& supported_versions,
QuicTime creation_time,
Perspective perspective)
: visitor_(nullptr),
error_(QUIC_NO_ERROR),
last_packet_number_(0),
largest_packet_number_(0),
last_serialized_connection_id_(0),
last_version_tag_(0),
supported_versions_(supported_versions),
decrypter_level_(ENCRYPTION_NONE),
alternative_decrypter_level_(ENCRYPTION_NONE),
alternative_decrypter_latch_(false),
perspective_(perspective),
validate_flags_(true),
creation_time_(creation_time),
last_timestamp_(QuicTime::Delta::Zero()) {
DCHECK(!supported_versions.empty());
quic_version_ = supported_versions_[0];
decrypter_ = QuicMakeUnique<NullDecrypter>(perspective);
encrypter_[ENCRYPTION_NONE] = QuicMakeUnique<NullEncrypter>(perspective);
}
QuicFramer::~QuicFramer() {}
// static
size_t QuicFramer::GetMinStreamFrameSize(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(
QuicVersion version,
QuicPacketNumberLength largest_observed_length) {
size_t min_size = kQuicFrameTypeSize + largest_observed_length +
kQuicDeltaTimeLargestObservedSize;
return min_size + kQuicNumTimestampsSize;
}
// static
size_t QuicFramer::GetStopWaitingFrameSize(
QuicVersion version,
QuicPacketNumberLength packet_number_length) {
size_t min_size = kQuicFrameTypeSize + packet_number_length;
return min_size;
}
// static
size_t QuicFramer::GetRstStreamFrameSize() {
return kQuicFrameTypeSize + kQuicMaxStreamIdSize + kQuicMaxStreamOffsetSize +
kQuicErrorCodeSize;
}
// static
size_t QuicFramer::GetMinConnectionCloseFrameSize() {
return kQuicFrameTypeSize + kQuicErrorCodeSize + kQuicErrorDetailsLengthSize;
}
// static
size_t QuicFramer::GetMinGoAwayFrameSize() {
return kQuicFrameTypeSize + kQuicErrorCodeSize + kQuicErrorDetailsLengthSize +
kQuicMaxStreamIdSize;
}
// static
size_t QuicFramer::GetWindowUpdateFrameSize() {
return kQuicFrameTypeSize + kQuicMaxStreamIdSize + kQuicMaxStreamOffsetSize;
}
// static
size_t QuicFramer::GetBlockedFrameSize() {
return kQuicFrameTypeSize + kQuicMaxStreamIdSize;
}
// static
size_t QuicFramer::GetStreamIdSize(QuicStreamId stream_id) {
// Sizes are 1 through 4 bytes.
for (int i = 1; i <= 4; ++i) {
stream_id >>= 8;
if (stream_id == 0) {
return i;
}
}
QUIC_BUG << "Failed to determine StreamIDSize.";
return 4;
}
// static
size_t QuicFramer::GetStreamOffsetSize(QuicStreamOffset offset) {
// 0 is a special case.
if (offset == 0) {
return 0;
}
// 2 through 8 are the remaining sizes.
offset >>= 8;
for (int i = 2; i <= 8; ++i) {
offset >>= 8;
if (offset == 0) {
return i;
}
}
QUIC_BUG << "Failed to determine StreamOffsetSize.";
return 8;
}
// static
size_t QuicFramer::GetVersionNegotiationPacketSize(size_t number_versions) {
return kPublicFlagsSize + PACKET_8BYTE_CONNECTION_ID +
number_versions * kQuicVersionSize;
}
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,
QuicPacketNumberLength packet_number_length) {
// Prevent a rare crash reported in b/19458523.
if ((frame.type == STREAM_FRAME || frame.type == ACK_FRAME) &&
frame.stream_frame == nullptr) {
QUIC_BUG << "Cannot compute the length of a null frame. "
<< "type:" << frame.type << "free_bytes:" << free_bytes
<< " first_frame:" << first_frame << " last_frame:" << last_frame
<< " seq num length:" << packet_number_length;
set_error(QUIC_INTERNAL_ERROR);
visitor_->OnError(this);
return 0;
}
if (frame.type == PADDING_FRAME) {
if (frame.padding_frame.num_padding_bytes == -1) {
// Full padding to the end of the packet.
return free_bytes;
} else {
// Lite padding.
return free_bytes <
static_cast<size_t>(frame.padding_frame.num_padding_bytes)
? free_bytes
: frame.padding_frame.num_padding_bytes;
}
}
size_t frame_len =
ComputeFrameLength(frame, last_frame, packet_number_length);
if (frame_len <= free_bytes) {
// Frame fits within packet. Note that acks may be truncated.
return frame_len;
}
// Only truncate the first frame in a packet, so if subsequent ones go
// over, stop including more frames.
if (!first_frame) {
return 0;
}
bool can_truncate =
frame.type == ACK_FRAME &&
free_bytes >=
GetMinAckFrameSize(quic_version_, PACKET_6BYTE_PACKET_NUMBER);
if (can_truncate) {
// Truncate the frame so the packet will not exceed kMaxPacketSize.
// Note that we may not use every byte of the writer in this case.
QUIC_DLOG(INFO) << ENDPOINT
<< "Truncating large frame, free bytes: " << free_bytes;
return free_bytes;
}
return 0;
}
QuicFramer::AckFrameInfo::AckFrameInfo()
: max_block_length(0), first_block_length(0), num_ack_blocks(0) {}
QuicFramer::AckFrameInfo::AckFrameInfo(const AckFrameInfo& other) = default;
QuicFramer::AckFrameInfo::~AckFrameInfo() {}
size_t QuicFramer::BuildDataPacket(const QuicPacketHeader& header,
const QuicFrames& frames,
char* buffer,
size_t packet_length) {
QuicDataWriter writer(packet_length, buffer);
if (!AppendPacketHeader(header, &writer)) {
QUIC_BUG << "AppendPacketHeader failed";
return 0;
}
size_t i = 0;
for (const QuicFrame& frame : frames) {
// Determine if we should write stream frame length in header.
const bool no_stream_frame_length = i == frames.size() - 1;
if (!AppendTypeByte(frame, no_stream_frame_length, &writer)) {
QUIC_BUG << "AppendTypeByte failed";
return 0;
}
switch (frame.type) {
case PADDING_FRAME:
writer.WritePadding();
break;
case STREAM_FRAME:
if (!AppendStreamFrame(*frame.stream_frame, no_stream_frame_length,
&writer)) {
QUIC_BUG << "AppendStreamFrame failed";
return 0;
}
break;
case ACK_FRAME:
if (!AppendAckFrameAndTypeByte(*frame.ack_frame, &writer)) {
QUIC_BUG << "AppendAckFrameAndTypeByte failed";
return 0;
}
break;
case STOP_WAITING_FRAME:
if (!AppendStopWaitingFrame(header, *frame.stop_waiting_frame,
&writer)) {
QUIC_BUG << "AppendStopWaitingFrame failed";
return 0;
}
break;
case MTU_DISCOVERY_FRAME:
// MTU discovery frames are serialized as ping frames.
case PING_FRAME:
// Ping has no payload.
break;
case RST_STREAM_FRAME:
if (!AppendRstStreamFrame(*frame.rst_stream_frame, &writer)) {
QUIC_BUG << "AppendRstStreamFrame failed";
return 0;
}
break;
case CONNECTION_CLOSE_FRAME:
if (!AppendConnectionCloseFrame(*frame.connection_close_frame,
&writer)) {
QUIC_BUG << "AppendConnectionCloseFrame failed";
return 0;
}
break;
case GOAWAY_FRAME:
if (!AppendGoAwayFrame(*frame.goaway_frame, &writer)) {
QUIC_BUG << "AppendGoAwayFrame failed";
return 0;
}
break;
case WINDOW_UPDATE_FRAME:
if (!AppendWindowUpdateFrame(*frame.window_update_frame, &writer)) {
QUIC_BUG << "AppendWindowUpdateFrame failed";
return 0;
}
break;
case BLOCKED_FRAME:
if (!AppendBlockedFrame(*frame.blocked_frame, &writer)) {
QUIC_BUG << "AppendBlockedFrame failed";
return 0;
}
break;
default:
RaiseError(QUIC_INVALID_FRAME_DATA);
QUIC_BUG << "QUIC_INVALID_FRAME_DATA";
return 0;
}
++i;
}
return writer.length();
}
// static
std::unique_ptr<QuicEncryptedPacket> QuicFramer::BuildPublicResetPacket(
const QuicPublicResetPacket& packet) {
DCHECK(packet.public_header.reset_flag);
CryptoHandshakeMessage reset;
reset.set_tag(kPRST);
reset.SetValue(kRNON, packet.nonce_proof);
if (!FLAGS_quic_reloadable_flag_quic_remove_packet_number_from_public_reset) {
reset.SetValue(kRSEQ, packet.rejected_packet_number);
}
if (packet.client_address.host().address_family() !=
IpAddressFamily::IP_UNSPEC) {
// packet.client_address is non-empty.
QuicSocketAddressCoder address_coder(packet.client_address);
string serialized_address = address_coder.Encode();
if (serialized_address.empty()) {
return nullptr;
}
reset.SetStringPiece(kCADR, serialized_address);
}
const QuicData& reset_serialized = reset.GetSerialized();
size_t len =
kPublicFlagsSize + PACKET_8BYTE_CONNECTION_ID + reset_serialized.length();
std::unique_ptr<char[]> buffer(new char[len]);
QuicDataWriter writer(len, buffer.get());
uint8_t flags = static_cast<uint8_t>(PACKET_PUBLIC_FLAGS_RST |
PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID);
if (FLAGS_quic_reloadable_flag_quic_use_old_public_reset_packets) {
// TODO(rch): Remove this QUIC_VERSION_32 is retired.
flags |= static_cast<uint8_t>(PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD);
}
if (!writer.WriteUInt8(flags)) {
return nullptr;
}
if (!writer.WriteConnectionId(packet.public_header.connection_id)) {
return nullptr;
}
if (!writer.WriteBytes(reset_serialized.data(), reset_serialized.length())) {
return nullptr;
}
return QuicMakeUnique<QuicEncryptedPacket>(buffer.release(), len, true);
}
// static
std::unique_ptr<QuicEncryptedPacket> QuicFramer::BuildVersionNegotiationPacket(
QuicConnectionId connection_id,
const QuicVersionVector& versions) {
DCHECK(!versions.empty());
size_t len = GetVersionNegotiationPacketSize(versions.size());
std::unique_ptr<char[]> buffer(new char[len]);
QuicDataWriter writer(len, buffer.get());
uint8_t flags = static_cast<uint8_t>(
PACKET_PUBLIC_FLAGS_VERSION | PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID |
// TODO(rch): Remove this QUIC_VERSION_32 is retired.
PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD);
if (!writer.WriteUInt8(flags)) {
return nullptr;
}
if (!writer.WriteConnectionId(connection_id)) {
return nullptr;
}
for (QuicVersion version : versions) {
if (!writer.WriteUInt32(QuicVersionToQuicTag(version))) {
return nullptr;
}
}
return QuicMakeUnique<QuicEncryptedPacket>(buffer.release(), len, true);
}
bool QuicFramer::ProcessPacket(const QuicEncryptedPacket& packet) {
QuicDataReader reader(packet.data(), packet.length());
visitor_->OnPacket();
// First parse the public header.
QuicPacketPublicHeader public_header;
if (!ProcessPublicHeader(&reader, &public_header)) {
DCHECK_NE("", detailed_error_);
QUIC_DVLOG(1) << ENDPOINT << "Unable to process public header. Error: "
<< detailed_error_;
DCHECK_NE("", detailed_error_);
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (!visitor_->OnUnauthenticatedPublicHeader(public_header)) {
// The visitor suppresses further processing of the packet.
return true;
}
if (perspective_ == Perspective::IS_SERVER && public_header.version_flag &&
public_header.versions[0] != quic_version_) {
if (!visitor_->OnProtocolVersionMismatch(public_header.versions[0])) {
return true;
}
}
bool rv;
if (perspective_ == Perspective::IS_CLIENT && public_header.version_flag) {
rv = ProcessVersionNegotiationPacket(&reader, &public_header);
} else if (public_header.reset_flag) {
rv = ProcessPublicResetPacket(&reader, public_header);
} else if (packet.length() <= kMaxPacketSize) {
// The optimized decryption algorithm implementations run faster when
// operating on aligned memory.
QUIC_CACHELINE_ALIGNED char buffer[kMaxPacketSize];
rv = ProcessDataPacket(&reader, public_header, packet, buffer,
kMaxPacketSize);
} else {
std::unique_ptr<char[]> large_buffer(new char[packet.length()]);
rv = ProcessDataPacket(&reader, public_header, packet, large_buffer.get(),
packet.length());
QUIC_BUG_IF(rv) << "QUIC should never successfully process packets larger"
<< "than kMaxPacketSize. packet size:" << packet.length();
}
return rv;
}
bool QuicFramer::ProcessVersionNegotiationPacket(
QuicDataReader* reader,
QuicPacketPublicHeader* public_header) {
DCHECK_EQ(Perspective::IS_CLIENT, perspective_);
// 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(QuicDataReader* encrypted_reader,
const QuicPacketPublicHeader& public_header,
const QuicEncryptedPacket& packet,
char* decrypted_buffer,
size_t buffer_length) {
QuicPacketHeader header(public_header);
if (!ProcessUnauthenticatedHeader(encrypted_reader, &header)) {
DCHECK_NE("", detailed_error_);
QUIC_DVLOG(1)
<< ENDPOINT
<< "Unable to process packet header. Stopping parsing. Error: "
<< detailed_error_;
return false;
}
size_t decrypted_length = 0;
if (!DecryptPayload(encrypted_reader, header, packet, decrypted_buffer,
buffer_length, &decrypted_length)) {
set_detailed_error("Unable to decrypt payload.");
return RaiseError(QUIC_DECRYPTION_FAILURE);
}
QuicDataReader reader(decrypted_buffer, decrypted_length);
// Set the last packet number after we have decrypted the packet
// so we are confident is not attacker controlled.
SetLastPacketNumber(header);
if (!visitor_->OnPacketHeader(header)) {
// The visitor suppresses further processing of the packet.
return true;
}
if (packet.length() > kMaxPacketSize) {
// If the packet has gotten this far, it should not be too large.
QUIC_BUG << "Packet too large:" << packet.length();
return RaiseError(QUIC_PACKET_TOO_LARGE);
}
// Handle the payload.
if (!ProcessFrameData(&reader, header)) {
DCHECK_NE(QUIC_NO_ERROR, error_); // ProcessFrameData sets the error.
DCHECK_NE("", detailed_error_);
QUIC_DLOG(WARNING) << ENDPOINT << "Unable to process frame data. Error: "
<< detailed_error_;
return false;
}
visitor_->OnPacketComplete();
return true;
}
bool QuicFramer::ProcessPublicResetPacket(
QuicDataReader* reader,
const QuicPacketPublicHeader& public_header) {
QuicPublicResetPacket packet(public_header);
std::unique_ptr<CryptoHandshakeMessage> reset(
CryptoFramer::ParseMessage(reader->ReadRemainingPayload()));
if (!reset.get()) {
set_detailed_error("Unable to read reset message.");
return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET);
}
if (reset->tag() != kPRST) {
set_detailed_error("Incorrect message tag.");
return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET);
}
if (reset->GetUint64(kRNON, &packet.nonce_proof) != QUIC_NO_ERROR) {
set_detailed_error("Unable to read nonce proof.");
return RaiseError(QUIC_INVALID_PUBLIC_RST_PACKET);
}
// TODO(satyamshekhar): validate nonce to protect against DoS.
QuicStringPiece address;
if (reset->GetStringPiece(kCADR, &address)) {
QuicSocketAddressCoder address_coder;
if (address_coder.Decode(address.data(), address.length())) {
packet.client_address =
QuicSocketAddress(address_coder.ip(), address_coder.port());
}
}
visitor_->OnPublicResetPacket(packet);
return true;
}
bool QuicFramer::AppendPacketHeader(const QuicPacketHeader& header,
QuicDataWriter* writer) {
QUIC_DVLOG(1) << ENDPOINT << "Appending header: " << header;
uint8_t 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;
}
if (header.public_header.multipath_flag) {
public_flags |= PACKET_PUBLIC_FLAGS_MULTIPATH;
}
public_flags |=
GetSequenceNumberFlags(header.public_header.packet_number_length)
<< kPublicHeaderSequenceNumberShift;
if (header.public_header.nonce != nullptr) {
DCHECK_EQ(Perspective::IS_SERVER, perspective_);
public_flags |= PACKET_PUBLIC_FLAGS_NONCE;
}
switch (header.public_header.connection_id_length) {
case PACKET_0BYTE_CONNECTION_ID:
if (!writer->WriteUInt8(public_flags |
PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID)) {
return false;
}
break;
case PACKET_8BYTE_CONNECTION_ID:
public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID;
if (!FLAGS_quic_reloadable_flag_quic_remove_v33_hacks2 &&
perspective_ == Perspective::IS_CLIENT) {
public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD;
}
if (!writer->WriteUInt8(public_flags) ||
!writer->WriteConnectionId(header.public_header.connection_id)) {
return false;
}
break;
}
last_serialized_connection_id_ = header.public_header.connection_id;
if (header.public_header.version_flag) {
DCHECK_EQ(Perspective::IS_CLIENT, perspective_);
QuicTag tag = QuicVersionToQuicTag(quic_version_);
if (!writer->WriteUInt32(tag)) {
return false;
}
QUIC_DVLOG(1) << ENDPOINT << "version = " << quic_version_ << ", tag = '"
<< QuicTagToString(tag) << "'";
}
if (header.public_header.nonce != nullptr &&
!writer->WriteBytes(header.public_header.nonce,
kDiversificationNonceSize)) {
return false;
}
if (!AppendPacketSequenceNumber(header.public_header.packet_number_length,
header.packet_number, writer)) {
return false;
}
return true;
}
const QuicTime::Delta QuicFramer::CalculateTimestampFromWire(
uint32_t time_delta_us) {
// The new time_delta might have wrapped to the next epoch, or it
// might have reverse wrapped to the previous epoch, or it might
// remain in the same epoch. Select the time closest to the previous
// time.
//
// epoch_delta is the delta between epochs. A delta is 4 bytes of
// microseconds.
const uint64_t epoch_delta = UINT64_C(1) << 32;
uint64_t epoch = last_timestamp_.ToMicroseconds() & ~(epoch_delta - 1);
// Wrapping is safe here because a wrapped value will not be ClosestTo below.
uint64_t prev_epoch = epoch - epoch_delta;
uint64_t next_epoch = epoch + epoch_delta;
uint64_t time = ClosestTo(
last_timestamp_.ToMicroseconds(), epoch + time_delta_us,
ClosestTo(last_timestamp_.ToMicroseconds(), prev_epoch + time_delta_us,
next_epoch + time_delta_us));
return QuicTime::Delta::FromMicroseconds(time);
}
void QuicFramer::SetLastPacketNumber(const QuicPacketHeader& header) {
last_packet_number_ = header.packet_number;
largest_packet_number_ =
std::max(header.packet_number, largest_packet_number_);
}
QuicPacketNumber QuicFramer::CalculatePacketNumberFromWire(
QuicPacketNumberLength packet_number_length,
QuicPacketNumber base_packet_number,
QuicPacketNumber packet_number) const {
// The new packet number might have wrapped to the next epoch, or
// it might have reverse wrapped to the previous epoch, or it might
// remain in the same epoch. Select the packet number closest to the
// next expected packet number, the previous packet number plus 1.
// epoch_delta is the delta between epochs the packet number was serialized
// with, so the correct value is likely the same epoch as the last sequence
// number or an adjacent epoch.
const QuicPacketNumber epoch_delta = UINT64_C(1)
<< (8 * packet_number_length);
QuicPacketNumber next_packet_number = base_packet_number + 1;
QuicPacketNumber epoch = base_packet_number & ~(epoch_delta - 1);
QuicPacketNumber prev_epoch = epoch - epoch_delta;
QuicPacketNumber next_epoch = epoch + epoch_delta;
return ClosestTo(next_packet_number, epoch + packet_number,
ClosestTo(next_packet_number, prev_epoch + packet_number,
next_epoch + packet_number));
}
bool QuicFramer::ProcessPublicHeader(QuicDataReader* reader,
QuicPacketPublicHeader* public_header) {
uint8_t public_flags;
if (!reader->ReadBytes(&public_flags, 1)) {
set_detailed_error("Unable to read public flags.");
return false;
}
public_header->multipath_flag =
(public_flags & PACKET_PUBLIC_FLAGS_MULTIPATH) != 0;
public_header->reset_flag = (public_flags & PACKET_PUBLIC_FLAGS_RST) != 0;
public_header->version_flag =
(public_flags & PACKET_PUBLIC_FLAGS_VERSION) != 0;
if (validate_flags_ && !public_header->version_flag &&
public_flags > (FLAGS_quic_reloadable_flag_quic_remove_multipath_bit
? PACKET_PUBLIC_FLAGS_MAX_WITHOUT_MULTIPATH_FLAG
: 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_CONNECTION_ID) {
case PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID:
if (!reader->ReadConnectionId(&public_header->connection_id)) {
set_detailed_error("Unable to read ConnectionId.");
return false;
}
public_header->connection_id_length = PACKET_8BYTE_CONNECTION_ID;
break;
case PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID:
public_header->connection_id_length = PACKET_0BYTE_CONNECTION_ID;
public_header->connection_id = last_serialized_connection_id_;
break;
}
public_header->packet_number_length = ReadSequenceNumberLength(
public_flags >> kPublicHeaderSequenceNumberShift);
// Read the version only if the packet is from the client.
// version flag from the server means version negotiation packet.
if (public_header->version_flag && perspective_ == Perspective::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.
last_version_tag_ = version_tag;
QuicVersion version = QuicTagToQuicVersion(version_tag);
if (version == quic_version_ &&
public_flags > (FLAGS_quic_reloadable_flag_quic_remove_multipath_bit
? PACKET_PUBLIC_FLAGS_MAX_WITHOUT_MULTIPATH_FLAG
: PACKET_PUBLIC_FLAGS_MAX)) {
set_detailed_error("Illegal public flags value.");
return false;
}
public_header->versions.push_back(version);
}
// A nonce should only be present in packets from the server to the client,
// which are neither version negotiation nor public reset packets.
if (public_flags & PACKET_PUBLIC_FLAGS_NONCE &&
!(public_flags & PACKET_PUBLIC_FLAGS_VERSION) &&
!(public_flags & PACKET_PUBLIC_FLAGS_RST) &&
// The nonce flag from a client is ignored and is assumed to be an older
// client indicating an eight-byte connection ID.
perspective_ == Perspective::IS_CLIENT) {
if (!reader->ReadBytes(reinterpret_cast<uint8_t*>(last_nonce_.data()),
last_nonce_.size())) {
set_detailed_error("Unable to read nonce.");
return false;
}
public_header->nonce = &last_nonce_;
} else {
public_header->nonce = nullptr;
}
return true;
}
// static
QuicPacketNumberLength QuicFramer::GetMinSequenceNumberLength(
QuicPacketNumber packet_number) {
if (packet_number < 1 << (PACKET_1BYTE_PACKET_NUMBER * 8)) {
return PACKET_1BYTE_PACKET_NUMBER;
} else if (packet_number < 1 << (PACKET_2BYTE_PACKET_NUMBER * 8)) {
return PACKET_2BYTE_PACKET_NUMBER;
} else if (packet_number < UINT64_C(1) << (PACKET_4BYTE_PACKET_NUMBER * 8)) {
return PACKET_4BYTE_PACKET_NUMBER;
} else {
return PACKET_6BYTE_PACKET_NUMBER;
}
}
// static
uint8_t QuicFramer::GetSequenceNumberFlags(
QuicPacketNumberLength packet_number_length) {
switch (packet_number_length) {
case PACKET_1BYTE_PACKET_NUMBER:
return PACKET_FLAGS_1BYTE_PACKET;
case PACKET_2BYTE_PACKET_NUMBER:
return PACKET_FLAGS_2BYTE_PACKET;
case PACKET_4BYTE_PACKET_NUMBER:
return PACKET_FLAGS_4BYTE_PACKET;
case PACKET_6BYTE_PACKET_NUMBER:
return PACKET_FLAGS_6BYTE_PACKET;
default:
QUIC_BUG << "Unreachable case statement.";
return PACKET_FLAGS_6BYTE_PACKET;
}
}
// static
QuicFramer::AckFrameInfo QuicFramer::GetAckFrameInfo(
const QuicAckFrame& frame) {
AckFrameInfo new_ack_info;
if (frame.packets.Empty()) {
return new_ack_info;
}
// The first block is the last interval. It isn't encoded with the gap-length
// encoding, so skip it.
new_ack_info.first_block_length = frame.packets.LastIntervalLength();
auto itr = frame.packets.rbegin();
QuicPacketNumber previous_start = itr->min();
new_ack_info.max_block_length = itr->Length();
++itr;
// Don't do any more work after getting information for 256 ACK blocks; any
// more can't be encoded anyway.
for (; itr != frame.packets.rend() &&
new_ack_info.num_ack_blocks < std::numeric_limits<uint8_t>::max();
previous_start = itr->min(), ++itr) {
const auto& interval = *itr;
const QuicPacketNumber total_gap = previous_start - interval.max();
new_ack_info.num_ack_blocks +=
(total_gap + std::numeric_limits<uint8_t>::max() - 1) /
std::numeric_limits<uint8_t>::max();
new_ack_info.max_block_length =
std::max(new_ack_info.max_block_length, interval.Length());
}
return new_ack_info;
}
bool QuicFramer::ProcessUnauthenticatedHeader(QuicDataReader* encrypted_reader,
QuicPacketHeader* header) {
QuicPacketNumber base_packet_number = largest_packet_number_;
if (!ProcessPacketSequenceNumber(
encrypted_reader, header->public_header.packet_number_length,
base_packet_number, &header->packet_number)) {
set_detailed_error("Unable to read packet number.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (header->packet_number == 0u) {
set_detailed_error("packet numbers cannot be 0.");
return RaiseError(QUIC_INVALID_PACKET_HEADER);
}
if (!visitor_->OnUnauthenticatedHeader(*header)) {
set_detailed_error(
"Visitor asked to stop processing of unauthenticated header.");
return false;
}
return true;
}
bool QuicFramer::ProcessPacketSequenceNumber(
QuicDataReader* reader,
QuicPacketNumberLength packet_number_length,
QuicPacketNumber base_packet_number,
QuicPacketNumber* packet_number) {
QuicPacketNumber wire_packet_number = 0u;
if (!reader->ReadBytes(&wire_packet_number, packet_number_length)) {
return false;
}
// TODO(ianswett): Explore the usefulness of trying multiple packet numbers
// in case the first guess is incorrect.
*packet_number = CalculatePacketNumberFromWire(
packet_number_length, base_packet_number, wire_packet_number);
return true;
}
bool QuicFramer::ProcessFrameData(QuicDataReader* reader,
const QuicPacketHeader& header) {
if (reader->IsDoneReading()) {
set_detailed_error("Packet has no frames.");
return RaiseError(QUIC_MISSING_PAYLOAD);
}
while (!reader->IsDoneReading()) {
uint8_t frame_type;
if (!reader->ReadBytes(&frame_type, 1)) {
set_detailed_error("Unable to read frame type.");
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
if (frame_type & kQuicFrameTypeSpecialMask) {
// Stream Frame
if (frame_type & kQuicFrameTypeStreamMask) {
QuicStreamFrame frame;
if (!ProcessStreamFrame(reader, frame_type, &frame)) {
return RaiseError(QUIC_INVALID_STREAM_DATA);
}
if (!visitor_->OnStreamFrame(frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
// Ack Frame
if (frame_type & kQuicFrameTypeAckMask) {
QuicAckFrame frame;
if (!ProcessAckFrame(reader, frame_type, &frame)) {
return RaiseError(QUIC_INVALID_ACK_DATA);
}
if (!visitor_->OnAckFrame(frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "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.");
QUIC_DLOG(WARNING) << ENDPOINT << "Illegal frame type: "
<< static_cast<int>(frame_type);
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
switch (frame_type) {
case PADDING_FRAME: {
QuicPaddingFrame frame(reader->BytesRemaining());
if (!visitor_->OnPaddingFrame(frame)) {
QUIC_DVLOG(1) << "Visitor asked to stop further processing.";
}
// We're done with the packet.
return true;
}
case RST_STREAM_FRAME: {
QuicRstStreamFrame frame;
if (!ProcessRstStreamFrame(reader, &frame)) {
return RaiseError(QUIC_INVALID_RST_STREAM_DATA);
}
if (!visitor_->OnRstStreamFrame(frame)) {
QUIC_DVLOG(1) << "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case CONNECTION_CLOSE_FRAME: {
QuicConnectionCloseFrame frame;
if (!ProcessConnectionCloseFrame(reader, &frame)) {
return RaiseError(QUIC_INVALID_CONNECTION_CLOSE_DATA);
}
if (!visitor_->OnConnectionCloseFrame(frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case GOAWAY_FRAME: {
QuicGoAwayFrame goaway_frame;
if (!ProcessGoAwayFrame(reader, &goaway_frame)) {
return RaiseError(QUIC_INVALID_GOAWAY_DATA);
}
if (!visitor_->OnGoAwayFrame(goaway_frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case WINDOW_UPDATE_FRAME: {
QuicWindowUpdateFrame window_update_frame;
if (!ProcessWindowUpdateFrame(reader, &window_update_frame)) {
return RaiseError(QUIC_INVALID_WINDOW_UPDATE_DATA);
}
if (!visitor_->OnWindowUpdateFrame(window_update_frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case BLOCKED_FRAME: {
QuicBlockedFrame blocked_frame;
if (!ProcessBlockedFrame(reader, &blocked_frame)) {
return RaiseError(QUIC_INVALID_BLOCKED_DATA);
}
if (!visitor_->OnBlockedFrame(blocked_frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case STOP_WAITING_FRAME: {
QuicStopWaitingFrame stop_waiting_frame;
if (!ProcessStopWaitingFrame(reader, header, &stop_waiting_frame)) {
return RaiseError(QUIC_INVALID_STOP_WAITING_DATA);
}
if (!visitor_->OnStopWaitingFrame(stop_waiting_frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
case PING_FRAME: {
// Ping has no payload.
QuicPingFrame ping_frame;
if (!visitor_->OnPingFrame(ping_frame)) {
QUIC_DVLOG(1) << ENDPOINT
<< "Visitor asked to stop further processing.";
// Returning true since there was no parsing error.
return true;
}
continue;
}
default:
set_detailed_error("Illegal frame type.");
QUIC_DLOG(WARNING) << ENDPOINT << "Illegal frame type: "
<< static_cast<int>(frame_type);
return RaiseError(QUIC_INVALID_FRAME_DATA);
}
}
return true;
}
bool QuicFramer::ProcessStreamFrame(QuicDataReader* reader,
uint8_t frame_type,
QuicStreamFrame* frame) {
uint8_t stream_flags = frame_type;
stream_flags &= ~kQuicFrameTypeStreamMask;
// Read from right to left: StreamID, Offset, Data Length, Fin.
const uint8_t stream_id_length = (stream_flags & kQuicStreamIDLengthMask) + 1;
stream_flags >>= kQuicStreamIdShift;
uint8_t 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;
}
// TODO(ianswett): Don't use QuicStringPiece as an intermediary.
QuicStringPiece data;
if (has_data_length) {
if (!reader->ReadStringPiece16(&data)) {
set_detailed_error("Unable to read frame data.");
return false;
}
} else {
if (!reader->ReadStringPiece(&data, reader->BytesRemaining())) {
set_detailed_error("Unable to read frame data.");
return false;
}
}
frame->data_buffer = data.data();
frame->data_length = static_cast<uint16_t>(data.length());
return true;
}
bool QuicFramer::ProcessAckFrame(QuicDataReader* reader,
uint8_t frame_type,
QuicAckFrame* ack_frame) {
// Determine the two lengths from the frame type: largest acked length,
// ack block length.
const QuicPacketNumberLength ack_block_length =
ReadSequenceNumberLength(frame_type);
frame_type >>= kQuicSequenceNumberLengthShift;
const QuicPacketNumberLength largest_acked_length =
ReadSequenceNumberLength(frame_type);
frame_type >>= kQuicSequenceNumberLengthShift;
frame_type >>= kQuicHasMultipleAckBlocksShift;
bool has_ack_blocks = frame_type & kQuicHasMultipleAckBlocksMask;
if (!reader->ReadBytes(&ack_frame->largest_observed, largest_acked_length)) {
set_detailed_error("Unable to read largest acked.");
return false;
}
uint64_t ack_delay_time_us;
if (!reader->ReadUFloat16(&ack_delay_time_us)) {
set_detailed_error("Unable to read ack delay time.");
return false;
}
if (ack_delay_time_us == kUFloat16MaxValue) {
ack_frame->ack_delay_time = QuicTime::Delta::Infinite();
} else {
ack_frame->ack_delay_time =
QuicTime::Delta::FromMicroseconds(ack_delay_time_us);
}
uint8_t num_ack_blocks = 0;
if (has_ack_blocks) {
if (!reader->ReadBytes(&num_ack_blocks, 1)) {
set_detailed_error("Unable to read num of ack blocks.");
return false;
}
}
size_t first_block_length = 0;
if (!reader->ReadBytes(&first_block_length, ack_block_length)) {
set_detailed_error("Unable to read first ack block length.");
return false;
}
QuicPacketNumber first_received =
ack_frame->largest_observed + 1 - first_block_length;
ack_frame->packets.Add(first_received, ack_frame->largest_observed + 1);
if (num_ack_blocks > 0) {
for (size_t i = 0; i < num_ack_blocks; ++i) {
size_t gap = 0;
if (!reader->ReadBytes(&gap, PACKET_1BYTE_PACKET_NUMBER)) {
set_detailed_error("Unable to read gap to next ack block.");
return false;
}
size_t current_block_length = 0;
if (!reader->ReadBytes(&current_block_length, ack_block_length)) {
set_detailed_error("Unable to ack block length.");
return false;
}
first_received -= (gap + current_block_length);
if (current_block_length > 0) {
ack_frame->packets.Add(first_received,
first_received + current_block_length);
}
}
}
if (!ProcessTimestampsInAckFrame(reader, ack_frame)) {
return false;
}
return true;
}
bool QuicFramer::ProcessTimestampsInAckFrame(QuicDataReader* reader,
QuicAckFrame* ack_frame) {
uint8_t 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 > 0) {
uint8_t delta_from_largest_observed;
if (!reader->ReadBytes(&delta_from_largest_observed,
PACKET_1BYTE_PACKET_NUMBER)) {
set_detailed_error("Unable to read sequence delta in received packets.");
return false;
}
QuicPacketNumber seq_num =
ack_frame->largest_observed - delta_from_largest_observed;
// Time delta from the framer creation.
uint32_t 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;
}
last_timestamp_ = CalculateTimestampFromWire(time_delta_us);
ack_frame->received_packet_times.reserve(num_received_packets);
ack_frame->received_packet_times.push_back(
std::make_pair(seq_num, creation_time_ + last_timestamp_));
for (uint8_t i = 1; i < num_received_packets; ++i) {
if (!reader->ReadBytes(&delta_from_largest_observed,
PACKET_1BYTE_PACKET_NUMBER)) {
set_detailed_error(
"Unable to read sequence delta in received packets.");
return false;
}
seq_num = ack_frame->largest_observed - delta_from_largest_observed;
// Time delta from the previous timestamp.
uint64_t incremental_time_delta_us;
if (!reader->ReadUFloat16(&incremental_time_delta_us)) {
set_detailed_error(
"Unable to read incremental time delta in received packets.");
return false;
}
last_timestamp_ = last_timestamp_ + QuicTime::Delta::FromMicroseconds(
incremental_time_delta_us);
ack_frame->received_packet_times.push_back(
std::make_pair(seq_num, creation_time_ + last_timestamp_));
}
}
return true;
}
bool QuicFramer::ProcessStopWaitingFrame(QuicDataReader* reader,
const QuicPacketHeader& header,
QuicStopWaitingFrame* stop_waiting) {
QuicPacketNumber least_unacked_delta = 0;
if (!reader->ReadBytes(&least_unacked_delta,
header.public_header.packet_number_length)) {
set_detailed_error("Unable to read least unacked delta.");
return false;
}
DCHECK_GE(header.packet_number, least_unacked_delta);
stop_waiting->least_unacked = header.packet_number - least_unacked_delta;
return true;
}
bool QuicFramer::ProcessRstStreamFrame(QuicDataReader* reader,
QuicRstStreamFrame* frame) {
if (!reader->ReadUInt32(&frame->stream_id)) {
set_detailed_error("Unable to read stream_id.");
return false;
}
if (!reader->ReadUInt64(&frame->byte_offset)) {
set_detailed_error("Unable to read rst stream sent byte offset.");
return false;
}
uint32_t error_code;
if (!reader->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read rst stream error code.");
return false;
}
if (error_code >= QUIC_STREAM_LAST_ERROR) {
// Ignore invalid stream error code if any.
error_code = QUIC_STREAM_LAST_ERROR;
}
frame->error_code = static_cast<QuicRstStreamErrorCode>(error_code);
return true;
}
bool QuicFramer::ProcessConnectionCloseFrame(QuicDataReader* reader,
QuicConnectionCloseFrame* frame) {
uint32_t error_code;
if (!reader->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read connection close error code.");
return false;
}
if (error_code >= QUIC_LAST_ERROR) {
// Ignore invalid QUIC error code if any.
error_code = QUIC_LAST_ERROR;
}
frame->error_code = static_cast<QuicErrorCode>(error_code);
QuicStringPiece 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();
return true;
}
bool QuicFramer::ProcessGoAwayFrame(QuicDataReader* reader,
QuicGoAwayFrame* frame) {
uint32_t error_code;
if (!reader->ReadUInt32(&error_code)) {
set_detailed_error("Unable to read go away error code.");
return false;
}
if (error_code >= QUIC_LAST_ERROR) {
// Ignore invalid QUIC error code if any.
error_code = QUIC_LAST_ERROR;
}
frame->error_code = static_cast<QuicErrorCode>(error_code);
uint32_t stream_id;
if (!reader->ReadUInt32(&stream_id)) {
set_detailed_error("Unable to read last good stream id.");
return false;
}
frame->last_good_stream_id = static_cast<QuicStreamId>(stream_id);
QuicStringPiece 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;
}
bool QuicFramer::ProcessWindowUpdateFrame(QuicDataReader* reader,
QuicWindowUpdateFrame* frame) {
if (!reader->ReadUInt32(&frame->stream_id)) {
set_detailed_error("Unable to read stream_id.");
return false;
}
if (!reader->ReadUInt64(&frame->byte_offset)) {
set_detailed_error("Unable to read window byte_offset.");
return false;
}
return true;
}
bool QuicFramer::ProcessBlockedFrame(QuicDataReader* reader,
QuicBlockedFrame* frame) {
if (!reader->ReadUInt32(&frame->stream_id)) {
set_detailed_error("Unable to read stream_id.");
return false;
}
return true;
}
// static
QuicStringPiece QuicFramer::GetAssociatedDataFromEncryptedPacket(
QuicVersion version,
const QuicEncryptedPacket& encrypted,
QuicConnectionIdLength connection_id_length,
bool includes_version,
bool includes_diversification_nonce,
QuicPacketNumberLength packet_number_length) {
// TODO(ianswett): This is identical to QuicData::AssociatedData.
return QuicStringPiece(
encrypted.data(),
GetStartOfEncryptedData(version, connection_id_length, includes_version,
includes_diversification_nonce,
packet_number_length));
}
void QuicFramer::SetDecrypter(EncryptionLevel level, QuicDecrypter* decrypter) {
DCHECK(alternative_decrypter_.get() == nullptr);
DCHECK_GE(level, decrypter_level_);
decrypter_.reset(decrypter);
decrypter_level_ = level;
}
void QuicFramer::SetAlternativeDecrypter(EncryptionLevel level,
QuicDecrypter* decrypter,
bool latch_once_used) {
alternative_decrypter_.reset(decrypter);
alternative_decrypter_level_ = level;
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);
}
size_t QuicFramer::EncryptInPlace(EncryptionLevel level,
QuicPacketNumber packet_number,
size_t ad_len,
size_t total_len,
size_t buffer_len,
char* buffer) {
size_t output_length = 0;
if (!encrypter_[level]->EncryptPacket(
quic_version_, packet_number,
QuicStringPiece(buffer, ad_len), // Associated data
QuicStringPiece(buffer + ad_len, total_len - ad_len), // Plaintext
buffer + ad_len, // Destination buffer
&output_length, buffer_len - ad_len)) {
RaiseError(QUIC_ENCRYPTION_FAILURE);
return 0;
}
return ad_len + output_length;
}
size_t QuicFramer::EncryptPayload(EncryptionLevel level,
QuicPacketNumber packet_number,
const QuicPacket& packet,
char* buffer,
size_t buffer_len) {
DCHECK(encrypter_[level].get() != nullptr);
QuicStringPiece associated_data = packet.AssociatedData(quic_version_);
// Copy in the header, because the encrypter only populates the encrypted
// plaintext content.
const size_t ad_len = associated_data.length();
memmove(buffer, associated_data.data(), ad_len);
// Encrypt the plaintext into the buffer.
size_t output_length = 0;
if (!encrypter_[level]->EncryptPacket(
quic_version_, packet_number, associated_data,
packet.Plaintext(quic_version_), buffer + ad_len, &output_length,
buffer_len - ad_len)) {
RaiseError(QUIC_ENCRYPTION_FAILURE);
return 0;
}
return ad_len + output_length;
}
size_t QuicFramer::GetMaxPlaintextSize(size_t ciphertext_size) {
// In order to keep the code simple, we don't have the current encryption
// level to hand. Both the NullEncrypter and AES-GCM have a tag length of 12.
size_t min_plaintext_size = ciphertext_size;
for (int i = ENCRYPTION_NONE; i < NUM_ENCRYPTION_LEVELS; i++) {
if (encrypter_[i].get() != nullptr) {
size_t size = encrypter_[i]->GetMaxPlaintextSize(ciphertext_size);
if (size < min_plaintext_size) {
min_plaintext_size = size;
}
}
}
return min_plaintext_size;
}
bool QuicFramer::DecryptPayload(QuicDataReader* encrypted_reader,
const QuicPacketHeader& header,
const QuicEncryptedPacket& packet,
char* decrypted_buffer,
size_t buffer_length,
size_t* decrypted_length) {
QuicStringPiece encrypted = encrypted_reader->ReadRemainingPayload();
DCHECK(decrypter_.get() != nullptr);
QuicStringPiece associated_data = GetAssociatedDataFromEncryptedPacket(
quic_version_, packet, header.public_header.connection_id_length,
header.public_header.version_flag, header.public_header.nonce != nullptr,
header.public_header.packet_number_length);
bool success = decrypter_->DecryptPacket(
quic_version_, header.packet_number, associated_data, encrypted,
decrypted_buffer, decrypted_length, buffer_length);
if (success) {
visitor_->OnDecryptedPacket(decrypter_level_);
} else if (alternative_decrypter_.get() != nullptr) {
if (header.public_header.nonce != nullptr) {
DCHECK_EQ(perspective_, Perspective::IS_CLIENT);
alternative_decrypter_->SetDiversificationNonce(
*header.public_header.nonce);
}
bool try_alternative_decryption = true;
if (alternative_decrypter_level_ == ENCRYPTION_INITIAL) {
if (perspective_ == Perspective::IS_CLIENT) {
if (header.public_header.nonce == nullptr) {
// Can not use INITIAL decryption without a diversification nonce.
try_alternative_decryption = false;
}
} else {
DCHECK(header.public_header.nonce == nullptr);
}
}
if (try_alternative_decryption) {
success = alternative_decrypter_->DecryptPacket(
quic_version_, header.packet_number, associated_data, encrypted,
decrypted_buffer, decrypted_length, buffer_length);
}
if (success) {
visitor_->OnDecryptedPacket(alternative_decrypter_level_);
if (alternative_decrypter_latch_) {
// Switch to the alternative decrypter and latch so that we cannot
// switch back.
decrypter_ = std::move(alternative_decrypter_);
decrypter_level_ = alternative_decrypter_level_;
alternative_decrypter_level_ = ENCRYPTION_NONE;
} else {
// Switch the alternative decrypter so that we use it first next time.
decrypter_.swap(alternative_decrypter_);
EncryptionLevel level = alternative_decrypter_level_;
alternative_decrypter_level_ = decrypter_level_;
decrypter_level_ = level;
}
}
}
if (!success) {
QUIC_DVLOG(1) << ENDPOINT << "DecryptPacket failed for packet_number:"
<< header.packet_number;
return false;
}
return true;
}
size_t QuicFramer::GetAckFrameTimeStampSize(const QuicAckFrame& ack) {
if (ack.received_packet_times.empty()) {
return 0;
}
return 5 + 3 * (ack.received_packet_times.size() - 1);
}
size_t QuicFramer::GetAckFrameSize(
const QuicAckFrame& ack,
QuicPacketNumberLength packet_number_length) {
size_t ack_size = 0;
AckFrameInfo ack_info = GetAckFrameInfo(ack);
QuicPacketNumberLength largest_acked_length =
GetMinSequenceNumberLength(ack.largest_observed);
QuicPacketNumberLength ack_block_length =
GetMinSequenceNumberLength(ack_info.max_block_length);
ack_size = GetMinAckFrameSize(quic_version_, largest_acked_length);
// First ack block length.
ack_size += ack_block_length;
if (ack_info.num_ack_blocks != 0) {
ack_size += kNumberOfAckBlocksSize;
ack_size += std::min(ack_info.num_ack_blocks, kMaxAckBlocks) *
(ack_block_length + PACKET_1BYTE_PACKET_NUMBER);
}
// Include timestamps.
ack_size += GetAckFrameTimeStampSize(ack);
return ack_size;
}
size_t QuicFramer::ComputeFrameLength(
const QuicFrame& frame,
bool last_frame_in_packet,
QuicPacketNumberLength packet_number_length) {
switch (frame.type) {
case STREAM_FRAME:
return GetMinStreamFrameSize(frame.stream_frame->stream_id,
frame.stream_frame->offset,
last_frame_in_packet) +
frame.stream_frame->data_length;
case ACK_FRAME: {
return GetAckFrameSize(*frame.ack_frame, packet_number_length);
}
case STOP_WAITING_FRAME:
return GetStopWaitingFrameSize(quic_version_, packet_number_length);
case MTU_DISCOVERY_FRAME:
// MTU discovery frames are serialized as ping frames.
case PING_FRAME:
// Ping has no payload.
return kQuicFrameTypeSize;
case RST_STREAM_FRAME:
return GetRstStreamFrameSize();
case CONNECTION_CLOSE_FRAME:
return GetMinConnectionCloseFrameSize() +
frame.connection_close_frame->error_details.size();
case GOAWAY_FRAME:
return GetMinGoAwayFrameSize() + frame.goaway_frame->reason_phrase.size();
case WINDOW_UPDATE_FRAME:
return GetWindowUpdateFrameSize();
case BLOCKED_FRAME:
return GetBlockedFrameSize();
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 no_stream_frame_length,
QuicDataWriter* writer) {
uint8_t type_byte = 0;
switch (frame.type) {
case STREAM_FRAME: {
if (frame.stream_frame == nullptr) {
QUIC_BUG << "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 |= no_stream_frame_length ? 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:
return true;
case MTU_DISCOVERY_FRAME:
type_byte = static_cast<uint8_t>(PING_FRAME);
break;
default:
type_byte = static_cast<uint8_t>(frame.type);
break;
}
return writer->WriteUInt8(type_byte);
}
// static
bool QuicFramer::AppendPacketSequenceNumber(
QuicPacketNumberLength packet_number_length,
QuicPacketNumber packet_number,
QuicDataWriter* writer) {
// Ensure the entire packet number can be written.
if (writer->capacity() - writer->length() <
static_cast<size_t>(packet_number_length)) {
return false;
}
switch (packet_number_length) {
case PACKET_1BYTE_PACKET_NUMBER:
return writer->WriteUInt8(packet_number & k1ByteSequenceNumberMask);
break;
case PACKET_2BYTE_PACKET_NUMBER:
return writer->WriteUInt16(packet_number & k2ByteSequenceNumberMask);
break;
case PACKET_4BYTE_PACKET_NUMBER:
return writer->WriteUInt32(packet_number & k4ByteSequenceNumberMask);
break;
case PACKET_6BYTE_PACKET_NUMBER:
return writer->WriteUInt48(packet_number & k6ByteSequenceNumberMask);
break;
default:
DCHECK(false) << "packet_number_length: " << packet_number_length;
return false;
}
}
// static
bool QuicFramer::AppendAckBlock(uint8_t gap,
QuicPacketNumberLength length_length,
QuicPacketNumber length,
QuicDataWriter* writer) {
return AppendPacketSequenceNumber(PACKET_1BYTE_PACKET_NUMBER, gap, writer) &&
AppendPacketSequenceNumber(length_length, length, writer);
}
bool QuicFramer::AppendStreamFrame(const QuicStreamFrame& frame,
bool no_stream_frame_length,
QuicDataWriter* writer) {
if (!writer->WriteBytes(&frame.stream_id, GetStreamIdSize(frame.stream_id))) {
QUIC_BUG << "Writing stream id size failed.";
return false;
}
if (!writer->WriteBytes(&frame.offset, GetStreamOffsetSize(frame.offset))) {
QUIC_BUG << "Writing offset size failed.";
return false;
}
if (!no_stream_frame_length) {
if ((frame.data_length > std::numeric_limits<uint16_t>::max()) ||
!writer->WriteUInt16(static_cast<uint16_t>(frame.data_length))) {
QUIC_BUG << "Writing stream frame length failed";
return false;
}
}
if (!writer->WriteBytes(frame.data_buffer, frame.data_length)) {
QUIC_BUG << "Writing frame data failed.";
return false;
}
return true;
}
void QuicFramer::set_version(const QuicVersion version) {
DCHECK(IsSupportedVersion(version)) << QuicVersionToString(version);
quic_version_ = version;
}
bool QuicFramer::AppendAckFrameAndTypeByte(const QuicAckFrame& frame,
QuicDataWriter* writer) {
const AckFrameInfo new_ack_info = GetAckFrameInfo(frame);
QuicPacketNumber largest_acked = frame.largest_observed;
QuicPacketNumberLength largest_acked_length =
GetMinSequenceNumberLength(largest_acked);
QuicPacketNumberLength ack_block_length =
GetMinSequenceNumberLength(new_ack_info.max_block_length);
// Calculate available bytes for timestamps and ack blocks.
int32_t available_timestamp_and_ack_block_bytes =
writer->capacity() - writer->length() - ack_block_length -
GetMinAckFrameSize(quic_version_, largest_acked_length) -
(new_ack_info.num_ack_blocks != 0 ? kNumberOfAckBlocksSize : 0);
DCHECK_LE(0, available_timestamp_and_ack_block_bytes);
// Write out the type byte by setting the low order bits and doing shifts
// to make room for the next bit flags to be set.
// Whether there are multiple ack blocks.
uint8_t type_byte =
new_ack_info.num_ack_blocks == 0 ? 0 : kQuicHasMultipleAckBlocksMask;
type_byte <<= kQuicHasMultipleAckBlocksShift;
// Largest acked length.
type_byte <<= kQuicSequenceNumberLengthShift;
type_byte |= GetSequenceNumberFlags(largest_acked_length);
// Ack block length.
type_byte <<= kQuicSequenceNumberLengthShift;
type_byte |= GetSequenceNumberFlags(ack_block_length);
type_byte |= kQuicFrameTypeAckMask;
if (!writer->WriteUInt8(type_byte)) {
return false;
}
// Largest acked.
if (!AppendPacketSequenceNumber(largest_acked_length, largest_acked,
writer)) {
return false;
}
// Largest acked delta time.
uint64_t ack_delay_time_us = kUFloat16MaxValue;
if (!frame.ack_delay_time.IsInfinite()) {
DCHECK_LE(0u, frame.ack_delay_time.ToMicroseconds());
ack_delay_time_us = frame.ack_delay_time.ToMicroseconds();
}
if (!writer->WriteUFloat16(ack_delay_time_us)) {
return false;
}
size_t max_num_ack_blocks = available_timestamp_and_ack_block_bytes /
(ack_block_length + PACKET_1BYTE_PACKET_NUMBER);
// Number of ack blocks.
size_t num_ack_blocks =
std::min(new_ack_info.num_ack_blocks, max_num_ack_blocks);
if (num_ack_blocks > std::numeric_limits<uint8_t>::max()) {
num_ack_blocks = std::numeric_limits<uint8_t>::max();
}
if (num_ack_blocks > 0) {
if (!writer->WriteBytes(&num_ack_blocks, 1)) {
return false;
}
}
// First ack block length.
if (!AppendPacketSequenceNumber(ack_block_length,
new_ack_info.first_block_length, writer)) {
return false;
}
// Ack blocks.
if (num_ack_blocks > 0) {
size_t num_ack_blocks_written = 0;
// Append, in descending order from the largest ACKed packet, a series of
// ACK blocks that represents the successfully acknoweldged packets. Each
// appended gap/block length represents a descending delta from the previous
// block. i.e.:
// |--- length ---|--- gap ---|--- length ---|--- gap ---|--- largest ---|
// For gaps larger than can be represented by a single encoded gap, a 0
// length gap of the maximum is used, i.e.:
// |--- length ---|--- gap ---|- 0 -|--- gap ---|--- largest ---|
auto itr = frame.packets.rbegin();
QuicPacketNumber previous_start = itr->min();
++itr;
for (;
itr != frame.packets.rend() && num_ack_blocks_written < num_ack_blocks;
previous_start = itr->min(), ++itr) {
const auto& interval = *itr;
const QuicPacketNumber total_gap = previous_start - interval.max();
const size_t num_encoded_gaps =
(total_gap + std::numeric_limits<uint8_t>::max() - 1) /
std::numeric_limits<uint8_t>::max();
DCHECK_LE(0u, num_encoded_gaps);
// Append empty ACK blocks because the gap is longer than a single gap.
for (size_t i = 1;
i < num_encoded_gaps && num_ack_blocks_written < num_ack_blocks;
++i) {
if (!AppendAckBlock(std::numeric_limits<uint8_t>::max(),
ack_block_length, 0, writer)) {
return false;
}
++num_ack_blocks_written;
}
if (num_ack_blocks_written >= num_ack_blocks) {
if (QUIC_PREDICT_FALSE(num_ack_blocks_written != num_ack_blocks)) {
QUIC_BUG << "Wrote " << num_ack_blocks_written
<< ", expected to write " << num_ack_blocks;
}
break;
}
const uint8_t last_gap =
total_gap -
(num_encoded_gaps - 1) * std::numeric_limits<uint8_t>::max();
// Append the final ACK block with a non-empty size.
if (!AppendAckBlock(last_gap, ack_block_length, interval.Length(),
writer)) {
return false;
}
++num_ack_blocks_written;
}
DCHECK_EQ(num_ack_blocks, num_ack_blocks_written);
}
// Timestamps.
// If we don't have enough available space to append all the timestamps, don't
// append any of them.
if (writer->capacity() - writer->length() >=
GetAckFrameTimeStampSize(frame)) {
if (!AppendTimestampToAckFrame(frame, writer)) {
return false;
}
} else {
uint8_t num_received_packets = 0;
if (!writer->WriteBytes(&num_received_packets, 1)) {
return false;
}
}
return true;
}
bool QuicFramer::AppendTimestampToAckFrame(const QuicAckFrame& frame,
QuicDataWriter* writer) {
DCHECK_GE(std::numeric_limits<uint8_t>::max(),
frame.received_packet_times.size());
// num_received_packets is only 1 byte.
if (frame.received_packet_times.size() >
std::numeric_limits<uint8_t>::max()) {
return false;
}
uint8_t num_received_packets = frame.received_packet_times.size();
if (!writer->WriteBytes(&num_received_packets, 1)) {
return false;
}
if (num_received_packets == 0) {
return true;
}
PacketTimeVector::const_iterator it = frame.received_packet_times.begin();
QuicPacketNumber packet_number = it->first;
QuicPacketNumber delta_from_largest_observed =
frame.largest_observed - packet_number;
DCHECK_GE(std::numeric_limits<uint8_t>::max(), delta_from_largest_observed);
if (delta_from_largest_observed > std::numeric_limits<uint8_t>::max()) {
return false;
}
if (!writer->WriteUInt8(delta_from_largest_observed &
k1ByteSequenceNumberMask)) {
return false;
}
// Use the lowest 4 bytes of the time delta from the creation_time_.
const uint64_t time_epoch_delta_us = UINT64_C(1) << 32;
uint32_t time_delta_us =
static_cast<uint32_t>((it->second - creation_time_).ToMicroseconds() &
(time_epoch_delta_us - 1));
if (!writer->WriteBytes(&time_delta_us, sizeof(time_delta_us))) {
return false;
}
QuicTime prev_time = it->second;
for (++it; it != frame.received_packet_times.end(); ++it) {
packet_number = it->first;
delta_from_largest_observed = frame.largest_observed - packet_number;
if (delta_from_largest_observed > std::numeric_limits<uint8_t>::max()) {
return false;
}
if (!writer->WriteUInt8(delta_from_largest_observed &
k1ByteSequenceNumberMask)) {
return false;
}
uint64_t frame_time_delta_us = (it->second - prev_time).ToMicroseconds();
prev_time = it->second;
if (!writer->WriteUFloat16(frame_time_delta_us)) {
return false;
}
}
return true;
}
bool QuicFramer::AppendStopWaitingFrame(const QuicPacketHeader& header,
const QuicStopWaitingFrame& frame,
QuicDataWriter* writer) {
DCHECK_GE(header.packet_number, frame.least_unacked);
const QuicPacketNumber least_unacked_delta =
header.packet_number - frame.least_unacked;
const QuicPacketNumber length_shift =
header.public_header.packet_number_length * 8;
if (least_unacked_delta >> length_shift > 0) {
QUIC_BUG << "packet_number_length "
<< header.public_header.packet_number_length
<< " is too small for least_unacked_delta: " << least_unacked_delta
<< " packet_number:" << header.packet_number
<< " least_unacked:" << frame.least_unacked
<< " version:" << quic_version_;
return false;
}
if (!AppendPacketSequenceNumber(header.public_header.packet_number_length,
least_unacked_delta, writer)) {
QUIC_BUG << " seq failed: " << header.public_header.packet_number_length;
return false;
}
return true;
}
bool QuicFramer::AppendRstStreamFrame(const QuicRstStreamFrame& frame,
QuicDataWriter* writer) {
if (!writer->WriteUInt32(frame.stream_id)) {
return false;
}
if (!writer->WriteUInt64(frame.byte_offset)) {
return false;
}
uint32_t error_code = static_cast<uint32_t>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
return true;
}
bool QuicFramer::AppendConnectionCloseFrame(
const QuicConnectionCloseFrame& frame,
QuicDataWriter* writer) {
uint32_t error_code = static_cast<uint32_t>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
if (!writer->WriteStringPiece16(frame.error_details)) {
return false;
}
return true;
}
bool QuicFramer::AppendGoAwayFrame(const QuicGoAwayFrame& frame,
QuicDataWriter* writer) {
uint32_t error_code = static_cast<uint32_t>(frame.error_code);
if (!writer->WriteUInt32(error_code)) {
return false;
}
uint32_t stream_id = static_cast<uint32_t>(frame.last_good_stream_id);
if (!writer->WriteUInt32(stream_id)) {
return false;
}
if (!writer->WriteStringPiece16(frame.reason_phrase)) {
return false;
}
return true;
}
bool QuicFramer::AppendWindowUpdateFrame(const QuicWindowUpdateFrame& frame,
QuicDataWriter* writer) {
uint32_t stream_id = static_cast<uint32_t>(frame.stream_id);
if (!writer->WriteUInt32(stream_id)) {
return false;
}
if (!writer->WriteUInt64(frame.byte_offset)) {
return false;
}
return true;
}
bool QuicFramer::AppendBlockedFrame(const QuicBlockedFrame& frame,
QuicDataWriter* writer) {
uint32_t stream_id = static_cast<uint32_t>(frame.stream_id);
if (!writer->WriteUInt32(stream_id)) {
return false;
}
return true;
}
bool QuicFramer::RaiseError(QuicErrorCode error) {
QUIC_DLOG(INFO) << ENDPOINT << "Error: " << QuicErrorCodeToString(error)
<< " detail: " << detailed_error_;
set_error(error);
visitor_->OnError(this);
return false;
}
} // namespace net