97 lines
3.5 KiB
C++
97 lines
3.5 KiB
C++
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/*
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* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "net/dcsctp/packet/parameter/parameter.h"
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#include <stddef.h>
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#include <cstdint>
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#include <memory>
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#include <string>
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#include <utility>
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#include <vector>
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#include "absl/memory/memory.h"
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#include "absl/types/optional.h"
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#include "api/array_view.h"
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#include "net/dcsctp/common/math.h"
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#include "net/dcsctp/packet/bounded_byte_reader.h"
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#include "net/dcsctp/packet/parameter/add_incoming_streams_request_parameter.h"
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#include "net/dcsctp/packet/parameter/add_outgoing_streams_request_parameter.h"
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#include "net/dcsctp/packet/parameter/forward_tsn_supported_parameter.h"
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#include "net/dcsctp/packet/parameter/heartbeat_info_parameter.h"
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#include "net/dcsctp/packet/parameter/incoming_ssn_reset_request_parameter.h"
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#include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h"
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#include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h"
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#include "net/dcsctp/packet/parameter/ssn_tsn_reset_request_parameter.h"
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#include "net/dcsctp/packet/parameter/state_cookie_parameter.h"
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#include "net/dcsctp/packet/parameter/supported_extensions_parameter.h"
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#include "net/dcsctp/packet/tlv_trait.h"
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#include "rtc_base/logging.h"
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#include "rtc_base/strings/string_builder.h"
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namespace dcsctp {
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constexpr size_t kParameterHeaderSize = 4;
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Parameters::Builder& Parameters::Builder::Add(const Parameter& p) {
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// https://tools.ietf.org/html/rfc4960#section-3.2.1
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// "If the length of the parameter is not a multiple of 4 bytes, the sender
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// pads the parameter at the end (i.e., after the Parameter Value field) with
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// all zero bytes."
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if (data_.size() % 4 != 0) {
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data_.resize(RoundUpTo4(data_.size()));
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}
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p.SerializeTo(data_);
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return *this;
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}
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std::vector<ParameterDescriptor> Parameters::descriptors() const {
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rtc::ArrayView<const uint8_t> span(data_);
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std::vector<ParameterDescriptor> result;
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while (!span.empty()) {
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BoundedByteReader<kParameterHeaderSize> header(span);
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uint16_t type = header.Load16<0>();
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uint16_t length = header.Load16<2>();
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result.emplace_back(type, span.subview(0, length));
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size_t length_with_padding = RoundUpTo4(length);
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if (length_with_padding > span.size()) {
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break;
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}
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span = span.subview(length_with_padding);
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}
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return result;
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}
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absl::optional<Parameters> Parameters::Parse(
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rtc::ArrayView<const uint8_t> data) {
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// Validate the parameter descriptors
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rtc::ArrayView<const uint8_t> span(data);
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while (!span.empty()) {
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if (span.size() < kParameterHeaderSize) {
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RTC_DLOG(LS_WARNING) << "Insufficient parameter length";
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return absl::nullopt;
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}
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BoundedByteReader<kParameterHeaderSize> header(span);
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uint16_t length = header.Load16<2>();
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if (length < kParameterHeaderSize || length > span.size()) {
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RTC_DLOG(LS_WARNING) << "Invalid parameter length field";
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return absl::nullopt;
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}
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size_t length_with_padding = RoundUpTo4(length);
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if (length_with_padding > span.size()) {
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break;
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}
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span = span.subview(length_with_padding);
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}
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return Parameters(std::vector<uint8_t>(data.begin(), data.end()));
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}
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} // namespace dcsctp
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