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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/third_party/quic/core/quic_utils.h"
#include <algorithm>
#include <cstdint>
#include "net/third_party/quic/core/quic_constants.h"
#include "net/third_party/quic/core/quic_types.h"
#include "net/third_party/quic/platform/api/quic_aligned.h"
#include "net/third_party/quic/platform/api/quic_arraysize.h"
#include "net/third_party/quic/platform/api/quic_bug_tracker.h"
#include "net/third_party/quic/platform/api/quic_endian.h"
#include "net/third_party/quic/platform/api/quic_flags.h"
#include "net/third_party/quic/platform/api/quic_prefetch.h"
#include "net/third_party/quic/platform/api/quic_string.h"
#include "net/third_party/quic/platform/api/quic_uint128.h"
#include "starboard/memory.h"
namespace quic {
namespace {
// We know that >= GCC 4.8 and Clang have a __uint128_t intrinsic. Other
// compilers don't necessarily, notably MSVC.
#if defined(__x86_64__) && \
((defined(__GNUC__) && \
(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \
defined(__clang__))
#define QUIC_UTIL_HAS_UINT128 1
#endif
#ifdef QUIC_UTIL_HAS_UINT128
QuicUint128 IncrementalHashFast(QuicUint128 uhash, QuicStringPiece data) {
// This code ends up faster than the naive implementation for 2 reasons:
// 1. QuicUint128 is sufficiently complicated that the compiler
// cannot transform the multiplication by kPrime into a shift-multiply-add;
// it has go through all of the instructions for a 128-bit multiply.
// 2. Because there are so fewer instructions (around 13), the hot loop fits
// nicely in the instruction queue of many Intel CPUs.
// kPrime = 309485009821345068724781371
static const QuicUint128 kPrime =
(static_cast<QuicUint128>(16777216) << 64) + 315;
auto hi = QuicUint128High64(uhash);
auto lo = QuicUint128Low64(uhash);
QuicUint128 xhash = (static_cast<QuicUint128>(hi) << 64) + lo;
const uint8_t* octets = reinterpret_cast<const uint8_t*>(data.data());
for (size_t i = 0; i < data.length(); ++i) {
xhash = (xhash ^ static_cast<uint32_t>(octets[i])) * kPrime;
}
return MakeQuicUint128(QuicUint128High64(xhash), QuicUint128Low64(xhash));
}
#endif
#ifndef QUIC_UTIL_HAS_UINT128
// Slow implementation of IncrementalHash. In practice, only used by Chromium.
QuicUint128 IncrementalHashSlow(QuicUint128 hash, QuicStringPiece data) {
// kPrime = 309485009821345068724781371
static const QuicUint128 kPrime = MakeQuicUint128(16777216, 315);
const uint8_t* octets = reinterpret_cast<const uint8_t*>(data.data());
for (size_t i = 0; i < data.length(); ++i) {
hash = hash ^ MakeQuicUint128(0, octets[i]);
hash = hash * kPrime;
}
return hash;
}
#endif
QuicUint128 IncrementalHash(QuicUint128 hash, QuicStringPiece data) {
#ifdef QUIC_UTIL_HAS_UINT128
return IncrementalHashFast(hash, data);
#else
return IncrementalHashSlow(hash, data);
#endif
}
} // namespace
// static
uint64_t QuicUtils::FNV1a_64_Hash(QuicStringPiece data) {
static const uint64_t kOffset = UINT64_C(14695981039346656037);
static const uint64_t kPrime = UINT64_C(1099511628211);
const uint8_t* octets = reinterpret_cast<const uint8_t*>(data.data());
uint64_t hash = kOffset;
for (size_t i = 0; i < data.length(); ++i) {
hash = hash ^ octets[i];
hash = hash * kPrime;
}
return hash;
}
// static
QuicUint128 QuicUtils::FNV1a_128_Hash(QuicStringPiece data) {
return FNV1a_128_Hash_Three(data, QuicStringPiece(), QuicStringPiece());
}
// static
QuicUint128 QuicUtils::FNV1a_128_Hash_Two(QuicStringPiece data1,
QuicStringPiece data2) {
return FNV1a_128_Hash_Three(data1, data2, QuicStringPiece());
}
// static
QuicUint128 QuicUtils::FNV1a_128_Hash_Three(QuicStringPiece data1,
QuicStringPiece data2,
QuicStringPiece data3) {
// The two constants are defined as part of the hash algorithm.
// see http://www.isthe.com/chongo/tech/comp/fnv/
// kOffset = 144066263297769815596495629667062367629
const QuicUint128 kOffset = MakeQuicUint128(UINT64_C(7809847782465536322),
UINT64_C(7113472399480571277));
QuicUint128 hash = IncrementalHash(kOffset, data1);
if (data2.empty()) {
return hash;
}
hash = IncrementalHash(hash, data2);
if (data3.empty()) {
return hash;
}
return IncrementalHash(hash, data3);
}
// static
void QuicUtils::SerializeUint128Short(QuicUint128 v, uint8_t* out) {
const uint64_t lo = QuicUint128Low64(v);
const uint64_t hi = QuicUint128High64(v);
// This assumes that the system is little-endian.
memcpy(out, &lo, sizeof(lo));
memcpy(out + sizeof(lo), &hi, sizeof(hi) / 2);
}
#define RETURN_STRING_LITERAL(x) \
case x: \
return #x;
// static
const char* QuicUtils::EncryptionLevelToString(EncryptionLevel level) {
switch (level) {
RETURN_STRING_LITERAL(ENCRYPTION_NONE);
RETURN_STRING_LITERAL(ENCRYPTION_ZERO_RTT);
RETURN_STRING_LITERAL(ENCRYPTION_FORWARD_SECURE);
RETURN_STRING_LITERAL(NUM_ENCRYPTION_LEVELS);
}
return "INVALID_ENCRYPTION_LEVEL";
}
// static
const char* QuicUtils::TransmissionTypeToString(TransmissionType type) {
switch (type) {
RETURN_STRING_LITERAL(NOT_RETRANSMISSION);
RETURN_STRING_LITERAL(HANDSHAKE_RETRANSMISSION);
RETURN_STRING_LITERAL(LOSS_RETRANSMISSION);
RETURN_STRING_LITERAL(ALL_UNACKED_RETRANSMISSION);
RETURN_STRING_LITERAL(ALL_INITIAL_RETRANSMISSION);
RETURN_STRING_LITERAL(RTO_RETRANSMISSION);
RETURN_STRING_LITERAL(TLP_RETRANSMISSION);
RETURN_STRING_LITERAL(PROBING_RETRANSMISSION);
}
return "INVALID_TRANSMISSION_TYPE";
}
QuicString QuicUtils::AddressChangeTypeToString(AddressChangeType type) {
switch (type) {
RETURN_STRING_LITERAL(NO_CHANGE);
RETURN_STRING_LITERAL(PORT_CHANGE);
RETURN_STRING_LITERAL(IPV4_SUBNET_CHANGE);
RETURN_STRING_LITERAL(IPV4_TO_IPV6_CHANGE);
RETURN_STRING_LITERAL(IPV6_TO_IPV4_CHANGE);
RETURN_STRING_LITERAL(IPV6_TO_IPV6_CHANGE);
RETURN_STRING_LITERAL(IPV4_TO_IPV4_CHANGE);
}
return "INVALID_ADDRESS_CHANGE_TYPE";
}
const char* QuicUtils::SentPacketStateToString(SentPacketState state) {
switch (state) {
RETURN_STRING_LITERAL(OUTSTANDING);
RETURN_STRING_LITERAL(NEVER_SENT);
RETURN_STRING_LITERAL(ACKED);
RETURN_STRING_LITERAL(UNACKABLE);
RETURN_STRING_LITERAL(HANDSHAKE_RETRANSMITTED);
RETURN_STRING_LITERAL(LOST);
RETURN_STRING_LITERAL(TLP_RETRANSMITTED);
RETURN_STRING_LITERAL(RTO_RETRANSMITTED);
RETURN_STRING_LITERAL(PROBE_RETRANSMITTED);
}
return "INVALID_SENT_PACKET_STATE";
}
// static
const char* QuicUtils::QuicLongHeaderTypetoString(QuicLongHeaderType type) {
switch (type) {
RETURN_STRING_LITERAL(VERSION_NEGOTIATION);
RETURN_STRING_LITERAL(INITIAL);
RETURN_STRING_LITERAL(RETRY);
RETURN_STRING_LITERAL(HANDSHAKE);
RETURN_STRING_LITERAL(ZERO_RTT_PROTECTED);
default:
return "INVALID_PACKET_TYPE";
}
}
// static
AddressChangeType QuicUtils::DetermineAddressChangeType(
const QuicSocketAddress& old_address,
const QuicSocketAddress& new_address) {
if (!old_address.IsInitialized() || !new_address.IsInitialized() ||
old_address == new_address) {
return NO_CHANGE;
}
if (old_address.host() == new_address.host()) {
return PORT_CHANGE;
}
bool old_ip_is_ipv4 = old_address.host().IsIPv4() ? true : false;
bool migrating_ip_is_ipv4 = new_address.host().IsIPv4() ? true : false;
if (old_ip_is_ipv4 && !migrating_ip_is_ipv4) {
return IPV4_TO_IPV6_CHANGE;
}
if (!old_ip_is_ipv4) {
return migrating_ip_is_ipv4 ? IPV6_TO_IPV4_CHANGE : IPV6_TO_IPV6_CHANGE;
}
const int kSubnetMaskLength = 24;
if (old_address.host().InSameSubnet(new_address.host(), kSubnetMaskLength)) {
// Subnet part does not change (here, we use /24), which is considered to be
// caused by NATs.
return IPV4_SUBNET_CHANGE;
}
return IPV4_TO_IPV4_CHANGE;
}
// static
void QuicUtils::CopyToBuffer(const struct IOVEC* iov,
int iov_count,
size_t iov_offset,
size_t buffer_length,
char* buffer) {
int iovnum = 0;
while (iovnum < iov_count && iov_offset >= iov[iovnum].iov_len) {
iov_offset -= iov[iovnum].iov_len;
++iovnum;
}
DCHECK_LE(iovnum, iov_count);
DCHECK_LE(iov_offset, iov[iovnum].iov_len);
if (iovnum >= iov_count || buffer_length == 0) {
return;
}
// Unroll the first iteration that handles iov_offset.
const size_t iov_available = iov[iovnum].iov_len - iov_offset;
size_t copy_len = std::min(buffer_length, iov_available);
// Try to prefetch the next iov if there is at least one more after the
// current. Otherwise, it looks like an irregular access that the hardware
// prefetcher won't speculatively prefetch. Only prefetch one iov because
// generally, the iov_offset is not 0, input iov consists of 2K buffers and
// the output buffer is ~1.4K.
if (copy_len == iov_available && iovnum + 1 < iov_count) {
char* next_base = static_cast<char*>(iov[iovnum + 1].iov_base);
// Prefetch 2 cachelines worth of data to get the prefetcher started; leave
// it to the hardware prefetcher after that.
QuicPrefetchT0(next_base);
if (iov[iovnum + 1].iov_len >= 64) {
QuicPrefetchT0(next_base + QUIC_CACHELINE_SIZE);
}
}
const char* src = static_cast<char*>(iov[iovnum].iov_base) + iov_offset;
while (true) {
memcpy(buffer, src, copy_len);
buffer_length -= copy_len;
buffer += copy_len;
if (buffer_length == 0 || ++iovnum >= iov_count) {
break;
}
src = static_cast<char*>(iov[iovnum].iov_base);
copy_len = std::min(buffer_length, iov[iovnum].iov_len);
}
QUIC_BUG_IF(buffer_length > 0) << "Failed to copy entire length to buffer.";
}
// static
struct IOVEC QuicUtils::MakeIovec(QuicStringPiece data) {
struct IOVEC iov = {const_cast<char*>(data.data()),
static_cast<size_t>(data.size())};
return iov;
}
// static
bool QuicUtils::IsAckable(SentPacketState state) {
return state != NEVER_SENT && state != ACKED && state != UNACKABLE;
}
// static
bool QuicUtils::IsRetransmittableFrame(QuicFrameType type) {
switch (type) {
case ACK_FRAME:
case PADDING_FRAME:
case STOP_WAITING_FRAME:
case MTU_DISCOVERY_FRAME:
return false;
default:
return true;
}
}
// static
bool QuicUtils::IsHandshakeFrame(const QuicFrame& frame,
QuicTransportVersion transport_version) {
if (transport_version < QUIC_VERSION_47) {
return frame.type == STREAM_FRAME &&
frame.stream_frame.stream_id == GetCryptoStreamId(transport_version);
} else {
return frame.type == CRYPTO_FRAME;
}
}
// static
SentPacketState QuicUtils::RetransmissionTypeToPacketState(
TransmissionType retransmission_type) {
switch (retransmission_type) {
case ALL_UNACKED_RETRANSMISSION:
case ALL_INITIAL_RETRANSMISSION:
return UNACKABLE;
case HANDSHAKE_RETRANSMISSION:
return HANDSHAKE_RETRANSMITTED;
case LOSS_RETRANSMISSION:
return LOST;
case TLP_RETRANSMISSION:
return TLP_RETRANSMITTED;
case RTO_RETRANSMISSION:
return RTO_RETRANSMITTED;
case PROBING_RETRANSMISSION:
return PROBE_RETRANSMITTED;
default:
QUIC_BUG << QuicUtils::TransmissionTypeToString(retransmission_type)
<< " is not a retransmission_type";
return UNACKABLE;
}
}
// static
bool QuicUtils::IsIetfPacketHeader(uint8_t first_byte) {
return (first_byte & FLAGS_LONG_HEADER) || (first_byte & FLAGS_FIXED_BIT) ||
!(first_byte & FLAGS_DEMULTIPLEXING_BIT);
}
// static
bool QuicUtils::IsIetfPacketShortHeader(uint8_t first_byte) {
return IsIetfPacketHeader(first_byte) && !(first_byte & FLAGS_LONG_HEADER);
}
// static
QuicStreamId QuicUtils::GetInvalidStreamId(QuicTransportVersion version) {
return version == QUIC_VERSION_99 ? std::numeric_limits<QuicStreamId>::max()
: 0;
}
// static
QuicStreamId QuicUtils::GetCryptoStreamId(QuicTransportVersion version) {
// TODO(nharper): Change this to return GetInvalidStreamId for version 47 or
// greater. Currently, too many things break with that change.
return version == QUIC_VERSION_99 ? 0 : 1;
}
// static
QuicStreamId QuicUtils::GetHeadersStreamId(QuicTransportVersion version) {
return version == QUIC_VERSION_99 ? 4 : 3;
}
// static
bool QuicUtils::IsClientInitiatedStreamId(QuicTransportVersion version,
QuicStreamId id) {
if (id == GetInvalidStreamId(version)) {
return false;
}
return version == QUIC_VERSION_99 ? id % 2 == 0 : id % 2 != 0;
}
// static
bool QuicUtils::IsServerInitiatedStreamId(QuicTransportVersion version,
QuicStreamId id) {
if (id == GetInvalidStreamId(version)) {
return false;
}
return version == QUIC_VERSION_99 ? id % 2 != 0 : id % 2 == 0;
}
// static
bool QuicUtils::IsBidirectionalStreamId(QuicStreamId id) {
return id % 4 < 2;
}
// static
StreamType QuicUtils::GetStreamType(QuicStreamId id,
Perspective perspective,
bool peer_initiated) {
if (IsBidirectionalStreamId(id)) {
return BIDIRECTIONAL;
}
if (peer_initiated) {
if (perspective == Perspective::IS_SERVER) {
DCHECK_EQ(2u, id % 4);
} else {
DCHECK_EQ(Perspective::IS_CLIENT, perspective);
DCHECK_EQ(3u, id % 4);
}
return READ_UNIDIRECTIONAL;
}
if (perspective == Perspective::IS_SERVER) {
DCHECK_EQ(3u, id % 4);
} else {
DCHECK_EQ(Perspective::IS_CLIENT, perspective);
DCHECK_EQ(2u, id % 4);
}
return WRITE_UNIDIRECTIONAL;
}
// static
QuicStreamId QuicUtils::StreamIdDelta(QuicTransportVersion version) {
return version == QUIC_VERSION_99 ? 4 : 2;
}
// static
QuicStreamId QuicUtils::GetFirstBidirectionalStreamId(
QuicTransportVersion version,
Perspective perspective) {
if (perspective == Perspective::IS_CLIENT) {
return version == QUIC_VERSION_99 ? 4 : 3;
}
return version == QUIC_VERSION_99 ? 1 : 2;
}
// static
QuicStreamId QuicUtils::GetFirstUnidirectionalStreamId(
QuicTransportVersion version,
Perspective perspective) {
if (perspective == Perspective::IS_CLIENT) {
return version == QUIC_VERSION_99 ? 2 : 3;
}
return version == QUIC_VERSION_99 ? 3 : 2;
}
// static
QuicConnectionId QuicUtils::CreateRandomConnectionId() {
return CreateRandomConnectionId(QuicRandom::GetInstance());
}
// static
QuicConnectionId QuicUtils::CreateRandomConnectionId(QuicRandom* random) {
char connection_id_bytes[kQuicDefaultConnectionIdLength];
random->RandBytes(connection_id_bytes, QUIC_ARRAYSIZE(connection_id_bytes));
return QuicConnectionId(static_cast<char*>(connection_id_bytes),
QUIC_ARRAYSIZE(connection_id_bytes));
}
// static
bool QuicUtils::VariableLengthConnectionIdAllowedForVersion(
QuicTransportVersion version) {
// TODO(dschinazi): Allow in appropriate version when supported.
return false;
}
// static
QuicConnectionId QuicUtils::CreateZeroConnectionId(
QuicTransportVersion version) {
if (!VariableLengthConnectionIdAllowedForVersion(version)) {
char connection_id_bytes[8] = {0, 0, 0, 0, 0, 0, 0, 0};
return QuicConnectionId(static_cast<char*>(connection_id_bytes),
QUIC_ARRAYSIZE(connection_id_bytes));
}
return EmptyQuicConnectionId();
}
// static
bool QuicUtils::IsConnectionIdValidForVersion(QuicConnectionId connection_id,
QuicTransportVersion version) {
if (VariableLengthConnectionIdAllowedForVersion(version)) {
return true;
}
return connection_id.length() == kQuicDefaultConnectionIdLength;
}
QuicUint128 QuicUtils::GenerateStatelessResetToken(
QuicConnectionId connection_id) {
uint64_t data_bytes[3] = {0, 0, 0};
static_assert(sizeof(data_bytes) >= kQuicMaxConnectionIdLength,
"kQuicMaxConnectionIdLength changed");
memcpy(data_bytes, connection_id.data(), connection_id.length());
// This is designed so that the common case of 64bit connection IDs
// produces a stateless reset token that is equal to the connection ID
// interpreted as a 64bit unsigned integer, to facilitate debugging.
return MakeQuicUint128(
QuicEndian::NetToHost64(sizeof(uint64_t) ^ connection_id.length() ^
data_bytes[1] ^ data_bytes[2]),
QuicEndian::NetToHost64(data_bytes[0]));
}
#undef RETURN_STRING_LITERAL // undef for jumbo builds
} // namespace quic