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/*
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "net/dcsctp/socket/state_cookie.h"
#include <cstdint>
#include <optional>
#include <vector>
#include "api/array_view.h"
#include "net/dcsctp/packet/bounded_byte_reader.h"
#include "net/dcsctp/packet/bounded_byte_writer.h"
#include "net/dcsctp/socket/capabilities.h"
#include "rtc_base/logging.h"
namespace dcsctp {
// Magic values, which the state cookie is prefixed with.
constexpr uint32_t kMagic1 = 1684230979;
constexpr uint32_t kMagic2 = 1414541360;
constexpr size_t StateCookie::kCookieSize;
std::vector<uint8_t> StateCookie::Serialize() {
std::vector<uint8_t> cookie;
cookie.resize(kCookieSize);
BoundedByteWriter<kCookieSize> buffer(cookie);
buffer.Store32<0>(kMagic1);
buffer.Store32<4>(kMagic2);
buffer.Store32<8>(*peer_tag_);
buffer.Store32<12>(*my_tag_);
buffer.Store32<16>(*peer_initial_tsn_);
buffer.Store32<20>(*my_initial_tsn_);
buffer.Store32<24>(a_rwnd_);
buffer.Store32<28>(static_cast<uint32_t>(*tie_tag_ >> 32));
buffer.Store32<32>(static_cast<uint32_t>(*tie_tag_));
buffer.Store8<36>(capabilities_.partial_reliability);
buffer.Store8<37>(capabilities_.message_interleaving);
buffer.Store8<38>(capabilities_.reconfig);
buffer.Store8<39>(capabilities_.zero_checksum);
buffer.Store16<40>(capabilities_.negotiated_maximum_incoming_streams);
buffer.Store16<42>(capabilities_.negotiated_maximum_outgoing_streams);
return cookie;
}
std::optional<StateCookie> StateCookie::Deserialize(
rtc::ArrayView<const uint8_t> cookie) {
if (cookie.size() != kCookieSize) {
RTC_DLOG(LS_WARNING) << "Invalid state cookie: " << cookie.size()
<< " bytes";
return std::nullopt;
}
BoundedByteReader<kCookieSize> buffer(cookie);
uint32_t magic1 = buffer.Load32<0>();
uint32_t magic2 = buffer.Load32<4>();
if (magic1 != kMagic1 || magic2 != kMagic2) {
RTC_DLOG(LS_WARNING) << "Invalid state cookie; wrong magic";
return std::nullopt;
}
VerificationTag peer_tag(buffer.Load32<8>());
VerificationTag my_tag(buffer.Load32<12>());
TSN peer_initial_tsn(buffer.Load32<16>());
TSN my_initial_tsn(buffer.Load32<20>());
uint32_t a_rwnd = buffer.Load32<24>();
uint32_t tie_tag_upper = buffer.Load32<28>();
uint32_t tie_tag_lower = buffer.Load32<32>();
TieTag tie_tag(static_cast<uint64_t>(tie_tag_upper) << 32 |
static_cast<uint64_t>(tie_tag_lower));
Capabilities capabilities;
capabilities.partial_reliability = buffer.Load8<36>() != 0;
capabilities.message_interleaving = buffer.Load8<37>() != 0;
capabilities.reconfig = buffer.Load8<38>() != 0;
capabilities.zero_checksum = buffer.Load8<39>() != 0;
capabilities.negotiated_maximum_incoming_streams = buffer.Load16<40>();
capabilities.negotiated_maximum_outgoing_streams = buffer.Load16<42>();
return StateCookie(peer_tag, my_tag, peer_initial_tsn, my_initial_tsn, a_rwnd,
tie_tag, capabilities);
}
} // namespace dcsctp