| /* | |
| * Copyright (c) 2016 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 "modules/rtp_rtcp/source/rtcp_packet/sdes.h" | |
| #include <cstdint> | |
| #include <cstring> | |
| #include <string> | |
| #include <utility> | |
| #include <vector> | |
| #include "absl/strings/string_view.h" | |
| #include "modules/rtp_rtcp/source/byte_io.h" | |
| #include "modules/rtp_rtcp/source/rtcp_packet.h" | |
| #include "modules/rtp_rtcp/source/rtcp_packet/common_header.h" | |
| #include "rtc_base/checks.h" | |
| #include "rtc_base/logging.h" | |
| namespace webrtc { | |
| namespace rtcp { | |
| // Source Description (SDES) (RFC 3550). | |
| // | |
| // 0 1 2 3 | |
| // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| // header |V=2|P| SC | PT=SDES=202 | length | | |
| // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
| // chunk | SSRC/CSRC_1 | | |
| // 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| // | SDES items | | |
| // | ... | | |
| // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
| // chunk | SSRC/CSRC_2 | | |
| // 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| // | SDES items | | |
| // | ... | | |
| // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
| // | |
| // Canonical End-Point Identifier SDES Item (CNAME) | |
| // | |
| // 0 1 2 3 | |
| // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| // | CNAME=1 | length | user and domain name ... | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| namespace { | |
| const uint8_t kTerminatorTag = 0; | |
| const uint8_t kCnameTag = 1; | |
| size_t ChunkSize(const Sdes::Chunk& chunk) { | |
| // Chunk: | |
| // SSRC/CSRC (4 bytes) | CNAME=1 (1 byte) | length (1 byte) | cname | padding. | |
| size_t chunk_payload_size = 4 + 1 + 1 + chunk.cname.size(); | |
| size_t padding_size = 4 - (chunk_payload_size % 4); // Minimum 1. | |
| return chunk_payload_size + padding_size; | |
| } | |
| } // namespace | |
| Sdes::Sdes() : block_length_(RtcpPacket::kHeaderLength) {} | |
| Sdes::~Sdes() {} | |
| bool Sdes::Parse(const CommonHeader& packet) { | |
| RTC_DCHECK_EQ(packet.type(), kPacketType); | |
| uint8_t number_of_chunks = packet.count(); | |
| std::vector<Chunk> chunks; // Read chunk into temporary array, so that in | |
| // case of an error original array would stay | |
| // unchanged. | |
| size_t block_length = kHeaderLength; | |
| if (packet.payload_size_bytes() % 4 != 0) { | |
| RTC_LOG(LS_WARNING) << "Invalid payload size " | |
| << packet.payload_size_bytes() | |
| << " bytes for a valid Sdes packet. Size should be" | |
| " multiple of 4 bytes"; | |
| } | |
| const uint8_t* const payload_end = | |
| packet.payload() + packet.payload_size_bytes(); | |
| const uint8_t* looking_at = packet.payload(); | |
| chunks.resize(number_of_chunks); | |
| for (size_t i = 0; i < number_of_chunks;) { | |
| // Each chunk consumes at least 8 bytes. | |
| if (payload_end - looking_at < 8) { | |
| RTC_LOG(LS_WARNING) << "Not enough space left for chunk #" << (i + 1); | |
| return false; | |
| } | |
| chunks[i].ssrc = ByteReader<uint32_t>::ReadBigEndian(looking_at); | |
| looking_at += sizeof(uint32_t); | |
| bool cname_found = false; | |
| uint8_t item_type; | |
| while ((item_type = *(looking_at++)) != kTerminatorTag) { | |
| if (looking_at >= payload_end) { | |
| RTC_LOG(LS_WARNING) | |
| << "Unexpected end of packet while reading chunk #" << (i + 1) | |
| << ". Expected to find size of the text."; | |
| return false; | |
| } | |
| uint8_t item_length = *(looking_at++); | |
| const size_t kTerminatorSize = 1; | |
| if (looking_at + item_length + kTerminatorSize > payload_end) { | |
| RTC_LOG(LS_WARNING) | |
| << "Unexpected end of packet while reading chunk #" << (i + 1) | |
| << ". Expected to find text of size " << item_length; | |
| return false; | |
| } | |
| if (item_type == kCnameTag) { | |
| if (cname_found) { | |
| RTC_LOG(LS_WARNING) | |
| << "Found extra CNAME for same ssrc in chunk #" << (i + 1); | |
| return false; | |
| } | |
| cname_found = true; | |
| chunks[i].cname.assign(reinterpret_cast<const char*>(looking_at), | |
| item_length); | |
| } | |
| looking_at += item_length; | |
| } | |
| if (cname_found) { | |
| // block_length calculates length of the packet that would be generated by | |
| // Build/Create functions. Adjust it same way WithCName function does. | |
| block_length += ChunkSize(chunks[i]); | |
| ++i; | |
| } else { | |
| // RFC states CNAME item is mandatory. | |
| // But same time it allows chunk without items. | |
| // So while parsing, ignore all chunks without cname, | |
| // but do not fail the parse. | |
| RTC_LOG(LS_WARNING) << "CNAME not found for ssrc " << chunks[i].ssrc; | |
| --number_of_chunks; | |
| chunks.resize(number_of_chunks); | |
| } | |
| // Adjust to 32bit boundary. | |
| looking_at += (payload_end - looking_at) % 4; | |
| } | |
| chunks_ = std::move(chunks); | |
| block_length_ = block_length; | |
| return true; | |
| } | |
| bool Sdes::AddCName(uint32_t ssrc, absl::string_view cname) { | |
| RTC_DCHECK_LE(cname.length(), 0xffu); | |
| if (chunks_.size() >= kMaxNumberOfChunks) { | |
| RTC_LOG(LS_WARNING) << "Max SDES chunks reached."; | |
| return false; | |
| } | |
| Chunk chunk; | |
| chunk.ssrc = ssrc; | |
| chunk.cname = std::string(cname); | |
| chunks_.push_back(chunk); | |
| block_length_ += ChunkSize(chunk); | |
| return true; | |
| } | |
| size_t Sdes::BlockLength() const { | |
| return block_length_; | |
| } | |
| bool Sdes::Create(uint8_t* packet, | |
| size_t* index, | |
| size_t max_length, | |
| PacketReadyCallback callback) const { | |
| while (*index + BlockLength() > max_length) { | |
| if (!OnBufferFull(packet, index, callback)) | |
| return false; | |
| } | |
| const size_t index_end = *index + BlockLength(); | |
| CreateHeader(chunks_.size(), kPacketType, HeaderLength(), packet, index); | |
| for (const Sdes::Chunk& chunk : chunks_) { | |
| ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 0], chunk.ssrc); | |
| ByteWriter<uint8_t>::WriteBigEndian(&packet[*index + 4], kCnameTag); | |
| ByteWriter<uint8_t>::WriteBigEndian( | |
| &packet[*index + 5], static_cast<uint8_t>(chunk.cname.size())); | |
| memcpy(&packet[*index + 6], chunk.cname.data(), chunk.cname.size()); | |
| *index += (6 + chunk.cname.size()); | |
| // In each chunk, the list of items must be terminated by one or more null | |
| // octets. The next chunk must start on a 32-bit boundary. | |
| // CNAME (1 byte) | length (1 byte) | name | padding. | |
| size_t padding_size = 4 - ((6 + chunk.cname.size()) % 4); | |
| const int kPadding = 0; | |
| memset(packet + *index, kPadding, padding_size); | |
| *index += padding_size; | |
| } | |
| RTC_CHECK_EQ(*index, index_end); | |
| return true; | |
| } | |
| } // namespace rtcp | |
| } // namespace webrtc |