tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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common_header.cc (3165B)

      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 "modules/rtp_rtcp/source/rtcp_packet/common_header.h"
     12 
     13 #include <cstddef>
     14 #include <cstdint>
     15 
     16 #include "modules/rtp_rtcp/source/byte_io.h"
     17 #include "rtc_base/logging.h"
     18 
     19 namespace webrtc {
     20 namespace rtcp {
     21 //    0                   1           1       2                   3
     22 //    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
     23 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     24 // 0 |V=2|P|   C/F   |
     25 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     26 // 1                 |  Packet Type  |
     27 //   ----------------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     28 // 2                                 |             length            |
     29 //   --------------------------------+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     30 //
     31 // Common header for all RTCP packets, 4 octets.
     32 bool CommonHeader::Parse(const uint8_t* buffer, size_t size_bytes) {
     33  const uint8_t kVersion = 2;
     34 
     35  if (size_bytes < kHeaderSizeBytes) {
     36    RTC_LOG(LS_WARNING)
     37        << "Too little data (" << size_bytes << " byte"
     38        << (size_bytes != 1 ? "s" : "")
     39        << ") remaining in buffer to parse RTCP header (4 bytes).";
     40    return false;
     41  }
     42 
     43  uint8_t version = buffer[0] >> 6;
     44  if (version != kVersion) {
     45    RTC_LOG(LS_WARNING) << "Invalid RTCP header: Version must be "
     46                        << static_cast<int>(kVersion) << " but was "
     47                        << static_cast<int>(version);
     48    return false;
     49  }
     50 
     51  bool has_padding = (buffer[0] & 0x20) != 0;
     52  count_or_format_ = buffer[0] & 0x1F;
     53  packet_type_ = buffer[1];
     54  payload_size_ = ByteReader<uint16_t>::ReadBigEndian(&buffer[2]) * 4;
     55  payload_ = buffer + kHeaderSizeBytes;
     56  padding_size_ = 0;
     57 
     58  if (size_bytes < kHeaderSizeBytes + payload_size_) {
     59    RTC_LOG(LS_WARNING) << "Buffer too small (" << size_bytes
     60                        << " bytes) to fit an RtcpPacket with a header and "
     61                        << payload_size_ << " bytes.";
     62    return false;
     63  }
     64 
     65  if (has_padding) {
     66    if (payload_size_ == 0) {
     67      RTC_LOG(LS_WARNING)
     68          << "Invalid RTCP header: Padding bit set but 0 payload "
     69             "size specified.";
     70      return false;
     71    }
     72 
     73    padding_size_ = payload_[payload_size_ - 1];
     74    if (padding_size_ == 0) {
     75      RTC_LOG(LS_WARNING)
     76          << "Invalid RTCP header: Padding bit set but 0 padding "
     77             "size specified.";
     78      return false;
     79    }
     80    if (padding_size_ > payload_size_) {
     81      RTC_LOG(LS_WARNING) << "Invalid RTCP header: Too many padding bytes ("
     82                          << padding_size_ << ") for a packet payload size of "
     83                          << payload_size_ << " bytes.";
     84      return false;
     85    }
     86    payload_size_ -= padding_size_;
     87  }
     88  return true;
     89 }
     90 }  // namespace rtcp
     91 }  // namespace webrtc