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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/packet/parameter/parameter.h"
#include <stddef.h>
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "absl/memory/memory.h"
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "net/dcsctp/common/math.h"
#include "net/dcsctp/packet/bounded_byte_reader.h"
#include "net/dcsctp/packet/parameter/add_incoming_streams_request_parameter.h"
#include "net/dcsctp/packet/parameter/add_outgoing_streams_request_parameter.h"
#include "net/dcsctp/packet/parameter/forward_tsn_supported_parameter.h"
#include "net/dcsctp/packet/parameter/heartbeat_info_parameter.h"
#include "net/dcsctp/packet/parameter/incoming_ssn_reset_request_parameter.h"
#include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
#include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
#include "net/dcsctp/packet/parameter/ssn_tsn_reset_request_parameter.h"
#include "net/dcsctp/packet/parameter/state_cookie_parameter.h"
#include "net/dcsctp/packet/parameter/supported_extensions_parameter.h"
#include "net/dcsctp/packet/tlv_trait.h"
#include "rtc_base/logging.h"
#include "rtc_base/strings/string_builder.h"
namespace dcsctp {
constexpr size_t kParameterHeaderSize = 4;
Parameters::Builder& Parameters::Builder::Add(const Parameter& p) {
// https://tools.ietf.org/html/rfc4960#section-3.2.1
// "If the length of the parameter is not a multiple of 4 bytes, the sender
// pads the parameter at the end (i.e., after the Parameter Value field) with
// all zero bytes."
if (data_.size() % 4 != 0) {
data_.resize(RoundUpTo4(data_.size()));
}
p.SerializeTo(data_);
return *this;
}
std::vector<ParameterDescriptor> Parameters::descriptors() const {
rtc::ArrayView<const uint8_t> span(data_);
std::vector<ParameterDescriptor> result;
while (!span.empty()) {
BoundedByteReader<kParameterHeaderSize> header(span);
uint16_t type = header.Load16<0>();
uint16_t length = header.Load16<2>();
result.emplace_back(type, span.subview(0, length));
size_t length_with_padding = RoundUpTo4(length);
if (length_with_padding > span.size()) {
break;
}
span = span.subview(length_with_padding);
}
return result;
}
absl::optional<Parameters> Parameters::Parse(
rtc::ArrayView<const uint8_t> data) {
// Validate the parameter descriptors
rtc::ArrayView<const uint8_t> span(data);
while (!span.empty()) {
if (span.size() < kParameterHeaderSize) {
RTC_DLOG(LS_WARNING) << "Insufficient parameter length";
return absl::nullopt;
}
BoundedByteReader<kParameterHeaderSize> header(span);
uint16_t length = header.Load16<2>();
if (length < kParameterHeaderSize || length > span.size()) {
RTC_DLOG(LS_WARNING) << "Invalid parameter length field";
return absl::nullopt;
}
size_t length_with_padding = RoundUpTo4(length);
if (length_with_padding > span.size()) {
break;
}
span = span.subview(length_with_padding);
}
return Parameters(std::vector<uint8_t>(data.begin(), data.end()));
}
} // namespace dcsctp
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