tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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app.cc (3625B)

      1 /*
      2 *  Copyright (c) 2015 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/app.h"
     12 
     13 #include <cstdint>
     14 #include <cstring>
     15 
     16 #include "modules/rtp_rtcp/source/byte_io.h"
     17 #include "modules/rtp_rtcp/source/rtcp_packet/common_header.h"
     18 #include "rtc_base/checks.h"
     19 #include "rtc_base/logging.h"
     20 
     21 namespace webrtc {
     22 namespace rtcp {
     23 // Application-Defined packet (APP) (RFC 3550).
     24 //
     25 //     0                   1                   2                   3
     26 //     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
     27 //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     28 //    |V=2|P| subtype |   PT=APP=204  |             length            |
     29 //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     30 //  0 |                           SSRC/CSRC                           |
     31 //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     32 //  4 |                          name (ASCII)                         |
     33 //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     34 //  8 |                   application-dependent data                ...
     35 //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     36 
     37 App::App() : sub_type_(0), name_(0) {}
     38 
     39 App::~App() = default;
     40 
     41 bool App::Parse(const CommonHeader& packet) {
     42  RTC_DCHECK_EQ(packet.type(), kPacketType);
     43  if (packet.payload_size_bytes() < kAppBaseLength) {
     44    RTC_LOG(LS_WARNING) << "Packet is too small to be a valid APP packet";
     45    return false;
     46  }
     47  if (packet.payload_size_bytes() % 4 != 0) {
     48    RTC_LOG(LS_WARNING)
     49        << "Packet payload must be 32 bits aligned to make a valid APP packet";
     50    return false;
     51  }
     52  sub_type_ = packet.fmt();
     53  SetSenderSsrc(ByteReader<uint32_t>::ReadBigEndian(&packet.payload()[0]));
     54  name_ = ByteReader<uint32_t>::ReadBigEndian(&packet.payload()[4]);
     55  data_.SetData(packet.payload() + kAppBaseLength,
     56                packet.payload_size_bytes() - kAppBaseLength);
     57  return true;
     58 }
     59 
     60 void App::SetSubType(uint8_t subtype) {
     61  RTC_DCHECK_LE(subtype, 0x1f);
     62  sub_type_ = subtype;
     63 }
     64 
     65 void App::SetData(const uint8_t* data, size_t data_length) {
     66  RTC_DCHECK(data);
     67  RTC_DCHECK_EQ(data_length % 4, 0) << "Data must be 32 bits aligned.";
     68  RTC_DCHECK_LE(data_length, kMaxDataSize)
     69      << "App data size " << data_length << " exceed maximum of "
     70      << kMaxDataSize << " bytes.";
     71  data_.SetData(data, data_length);
     72 }
     73 
     74 size_t App::BlockLength() const {
     75  return kHeaderLength + kAppBaseLength + data_.size();
     76 }
     77 
     78 bool App::Create(uint8_t* packet,
     79                 size_t* index,
     80                 size_t max_length,
     81                 PacketReadyCallback callback) const {
     82  while (*index + BlockLength() > max_length) {
     83    if (!OnBufferFull(packet, index, callback))
     84      return false;
     85  }
     86  const size_t index_end = *index + BlockLength();
     87  CreateHeader(sub_type_, kPacketType, HeaderLength(), packet, index);
     88 
     89  ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 0], sender_ssrc());
     90  ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 4], name_);
     91  if (!data_.empty()) {
     92    memcpy(&packet[*index + 8], data_.data(), data_.size());
     93  }
     94  *index += (8 + data_.size());
     95  RTC_DCHECK_EQ(index_end, *index);
     96  return true;
     97 }
     98 
     99 }  // namespace rtcp
    100 }  // namespace webrtc