| /* |
| * Copyright (c) 2015 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/bye.h" |
| |
| #include <string.h> |
| |
| #include <cstdint> |
| #include <utility> |
| |
| #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 { |
| constexpr uint8_t Bye::kPacketType; |
| // Bye packet (BYE) (RFC 3550). |
| // |
| // 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 |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // |V=2|P| SC | PT=BYE=203 | length | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // | SSRC/CSRC | |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // : ... : |
| // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
| // (opt) | length | reason for leaving ... |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Bye::Bye() : sender_ssrc_(0) {} |
| |
| Bye::~Bye() = default; |
| |
| bool Bye::Parse(const CommonHeader& packet) { |
| RTC_DCHECK_EQ(packet.type(), kPacketType); |
| |
| const uint8_t src_count = packet.count(); |
| // Validate packet. |
| if (packet.payload_size_bytes() < 4u * src_count) { |
| RTC_LOG(LS_WARNING) |
| << "Packet is too small to contain CSRCs it promise to have."; |
| return false; |
| } |
| const uint8_t* const payload = packet.payload(); |
| bool has_reason = packet.payload_size_bytes() > 4u * src_count; |
| uint8_t reason_length = 0; |
| if (has_reason) { |
| reason_length = payload[4u * src_count]; |
| if (packet.payload_size_bytes() - 4u * src_count < 1u + reason_length) { |
| RTC_LOG(LS_WARNING) << "Invalid reason length: " << reason_length; |
| return false; |
| } |
| } |
| // Once sure packet is valid, copy values. |
| if (src_count == 0) { // A count value of zero is valid, but useless. |
| sender_ssrc_ = 0; |
| csrcs_.clear(); |
| } else { |
| sender_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(payload); |
| csrcs_.resize(src_count - 1); |
| for (size_t i = 1; i < src_count; ++i) |
| csrcs_[i - 1] = ByteReader<uint32_t>::ReadBigEndian(&payload[4 * i]); |
| } |
| |
| if (has_reason) { |
| reason_.assign(reinterpret_cast<const char*>(&payload[4u * src_count + 1]), |
| reason_length); |
| } else { |
| reason_.clear(); |
| } |
| |
| return true; |
| } |
| |
| bool Bye::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(1 + csrcs_.size(), kPacketType, HeaderLength(), packet, index); |
| // Store srcs of the leaving clients. |
| ByteWriter<uint32_t>::WriteBigEndian(&packet[*index], sender_ssrc_); |
| *index += sizeof(uint32_t); |
| for (uint32_t csrc : csrcs_) { |
| ByteWriter<uint32_t>::WriteBigEndian(&packet[*index], csrc); |
| *index += sizeof(uint32_t); |
| } |
| // Store the reason to leave. |
| if (!reason_.empty()) { |
| uint8_t reason_length = static_cast<uint8_t>(reason_.size()); |
| packet[(*index)++] = reason_length; |
| memcpy(&packet[*index], reason_.data(), reason_length); |
| *index += reason_length; |
| // Add padding bytes if needed. |
| size_t bytes_to_pad = index_end - *index; |
| RTC_DCHECK_LE(bytes_to_pad, 3); |
| if (bytes_to_pad > 0) { |
| memset(&packet[*index], 0, bytes_to_pad); |
| *index += bytes_to_pad; |
| } |
| } |
| RTC_DCHECK_EQ(index_end, *index); |
| return true; |
| } |
| |
| bool Bye::SetCsrcs(std::vector<uint32_t> csrcs) { |
| if (csrcs.size() > kMaxNumberOfCsrcs) { |
| RTC_LOG(LS_WARNING) << "Too many CSRCs for Bye packet."; |
| return false; |
| } |
| csrcs_ = std::move(csrcs); |
| return true; |
| } |
| |
| void Bye::SetReason(std::string reason) { |
| RTC_DCHECK_LE(reason.size(), 0xffu); |
| reason_ = std::move(reason); |
| } |
| |
| size_t Bye::BlockLength() const { |
| size_t src_count = (1 + csrcs_.size()); |
| size_t reason_size_in_32bits = reason_.empty() ? 0 : (reason_.size() / 4 + 1); |
| return kHeaderLength + 4 * (src_count + reason_size_in_32bits); |
| } |
| |
| } // namespace rtcp |
| } // namespace webrtc |