1 /* 2 * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 #include "net/dcsctp/packet/parameter/parameter.h" 11 12 #include <stddef.h> 13 14 #include <cstdint> 15 #include <memory> 16 #include <string> 17 #include <utility> 18 #include <vector> 19 20 #include "absl/memory/memory.h" 21 #include "absl/types/optional.h" 22 #include "api/array_view.h" 23 #include "net/dcsctp/common/math.h" 24 #include "net/dcsctp/packet/bounded_byte_reader.h" 25 #include "net/dcsctp/packet/parameter/add_incoming_streams_request_parameter.h" 26 #include "net/dcsctp/packet/parameter/add_outgoing_streams_request_parameter.h" 27 #include "net/dcsctp/packet/parameter/forward_tsn_supported_parameter.h" 28 #include "net/dcsctp/packet/parameter/heartbeat_info_parameter.h" 29 #include "net/dcsctp/packet/parameter/incoming_ssn_reset_request_parameter.h" 30 #include "net/dcsctp/packet/parameter/outgoing_ssn_reset_request_parameter.h" 31 #include "net/dcsctp/packet/parameter/reconfiguration_response_parameter.h" 32 #include "net/dcsctp/packet/parameter/ssn_tsn_reset_request_parameter.h" 33 #include "net/dcsctp/packet/parameter/state_cookie_parameter.h" 34 #include "net/dcsctp/packet/parameter/supported_extensions_parameter.h" 35 #include "net/dcsctp/packet/tlv_trait.h" 36 #include "rtc_base/logging.h" 37 #include "rtc_base/strings/string_builder.h" 38 39 namespace dcsctp { 40 41 constexpr size_t kParameterHeaderSize = 4; 42 Add(const Parameter & p)43Parameters::Builder& Parameters::Builder::Add(const Parameter& p) { 44 // https://tools.ietf.org/html/rfc4960#section-3.2.1 45 // "If the length of the parameter is not a multiple of 4 bytes, the sender 46 // pads the parameter at the end (i.e., after the Parameter Value field) with 47 // all zero bytes." 48 if (data_.size() % 4 != 0) { 49 data_.resize(RoundUpTo4(data_.size())); 50 } 51 52 p.SerializeTo(data_); 53 return *this; 54 } 55 descriptors() const56std::vector<ParameterDescriptor> Parameters::descriptors() const { 57 rtc::ArrayView<const uint8_t> span(data_); 58 std::vector<ParameterDescriptor> result; 59 while (!span.empty()) { 60 BoundedByteReader<kParameterHeaderSize> header(span); 61 uint16_t type = header.Load16<0>(); 62 uint16_t length = header.Load16<2>(); 63 result.emplace_back(type, span.subview(0, length)); 64 size_t length_with_padding = RoundUpTo4(length); 65 if (length_with_padding > span.size()) { 66 break; 67 } 68 span = span.subview(length_with_padding); 69 } 70 return result; 71 } 72 Parse(rtc::ArrayView<const uint8_t> data)73absl::optional<Parameters> Parameters::Parse( 74 rtc::ArrayView<const uint8_t> data) { 75 // Validate the parameter descriptors 76 rtc::ArrayView<const uint8_t> span(data); 77 while (!span.empty()) { 78 if (span.size() < kParameterHeaderSize) { 79 RTC_DLOG(LS_WARNING) << "Insufficient parameter length"; 80 return absl::nullopt; 81 } 82 BoundedByteReader<kParameterHeaderSize> header(span); 83 uint16_t length = header.Load16<2>(); 84 if (length < kParameterHeaderSize || length > span.size()) { 85 RTC_DLOG(LS_WARNING) << "Invalid parameter length field"; 86 return absl::nullopt; 87 } 88 size_t length_with_padding = RoundUpTo4(length); 89 if (length_with_padding > span.size()) { 90 break; 91 } 92 span = span.subview(length_with_padding); 93 } 94 return Parameters(std::vector<uint8_t>(data.begin(), data.end())); 95 } 96 } // namespace dcsctp 97