Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2016 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             : 
      11             : #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/common_header.h"
      12             : 
      13             : #include "webrtc/base/logging.h"
      14             : #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
      15             : 
      16             : namespace webrtc {
      17             : namespace rtcp {
      18             : //    0                   1           1       2                   3
      19             : //    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
      20             : //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      21             : // 0 |V=2|P|   C/F   |
      22             : //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      23             : // 1                 |  Packet Type  |
      24             : //   ----------------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      25             : // 2                                 |             length            |
      26             : //   --------------------------------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      27             : //
      28             : // Common header for all RTCP packets, 4 octets.
      29           0 : bool CommonHeader::Parse(const uint8_t* buffer, size_t size_bytes) {
      30           0 :   const size_t kHeaderSizeBytes = 4;
      31           0 :   const uint8_t kVersion = 2;
      32             : 
      33           0 :   if (size_bytes < kHeaderSizeBytes) {
      34           0 :     LOG(LS_WARNING) << "Too little data (" << size_bytes << " byte"
      35             :                     << (size_bytes != 1 ? "s" : "")
      36           0 :                     << ") remaining in buffer to parse RTCP header (4 bytes).";
      37           0 :     return false;
      38             :   }
      39             : 
      40           0 :   uint8_t version = buffer[0] >> 6;
      41           0 :   if (version != kVersion) {
      42           0 :     LOG(LS_WARNING) << "Invalid RTCP header: Version must be "
      43           0 :                     << static_cast<int>(kVersion) << " but was "
      44           0 :                     << static_cast<int>(version);
      45           0 :     return false;
      46             :   }
      47             : 
      48           0 :   bool has_padding = (buffer[0] & 0x20) != 0;
      49           0 :   count_or_format_ = buffer[0] & 0x1F;
      50           0 :   packet_type_ = buffer[1];
      51           0 :   payload_size_ = ByteReader<uint16_t>::ReadBigEndian(&buffer[2]) * 4;
      52           0 :   payload_ = buffer + kHeaderSizeBytes;
      53           0 :   padding_size_ = 0;
      54             : 
      55           0 :   if (size_bytes < kHeaderSizeBytes + payload_size_) {
      56           0 :     LOG(LS_WARNING) << "Buffer too small (" << size_bytes
      57           0 :                     << " bytes) to fit an RtcpPacket with a header and "
      58           0 :                     << payload_size_ << " bytes.";
      59           0 :     return false;
      60             :   }
      61             : 
      62           0 :   if (has_padding) {
      63           0 :     if (payload_size_ == 0) {
      64           0 :       LOG(LS_WARNING) << "Invalid RTCP header: Padding bit set but 0 payload "
      65           0 :                          "size specified.";
      66           0 :       return false;
      67             :     }
      68             : 
      69           0 :     padding_size_ = payload_[payload_size_ - 1];
      70           0 :     if (padding_size_ == 0) {
      71           0 :       LOG(LS_WARNING) << "Invalid RTCP header: Padding bit set but 0 padding "
      72           0 :                          "size specified.";
      73           0 :       return false;
      74             :     }
      75           0 :     if (padding_size_ > payload_size_) {
      76           0 :       LOG(LS_WARNING) << "Invalid RTCP header: Too many padding bytes ("
      77           0 :                       << padding_size_ << ") for a packet payload size of "
      78           0 :                       << payload_size_ << " bytes.";
      79           0 :       return false;
      80             :     }
      81           0 :     payload_size_ -= padding_size_;
      82             :   }
      83           0 :   return true;
      84             : }
      85             : }  // namespace rtcp
      86             : }  // namespace webrtc