| /* |
| * 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 <string.h> |
| |
| #include <utility> |
| |
| #include "absl/strings/string_view.h" |
| #include "modules/rtp_rtcp/source/byte_io.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 |
