276 lines
9.4 KiB
C++
276 lines
9.4 KiB
C++
/*
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* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
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*
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* This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
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*
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* Use of this source code is governed by MIT license that can be found in the
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* LICENSE file in the root of the source tree. All contributing project authors
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* may be found in the AUTHORS file in the root of the source tree.
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*/
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#if defined(ENABLE_RTPPROXY)
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#include "RtpSession.h"
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#include "RtpSelector.h"
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#include "Network/TcpServer.h"
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#include "Rtsp/Rtsp.h"
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#include "Rtsp/RtpReceiver.h"
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#include "Common/config.h"
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using namespace std;
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using namespace toolkit;
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namespace mediakit{
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const string RtpSession::kStreamID = "stream_id";
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const string RtpSession::kSSRC = "ssrc";
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const string RtpSession::kOnlyAudio = "only_audio";
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void RtpSession::attachServer(const Server &server) {
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setParams(const_cast<Server &>(server));
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}
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void RtpSession::setParams(mINI &ini) {
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_stream_id = ini[kStreamID];
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_ssrc = ini[kSSRC];
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_only_audio = ini[kOnlyAudio];
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}
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RtpSession::RtpSession(const Socket::Ptr &sock) : Session(sock) {
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socklen_t addr_len = sizeof(_addr);
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getpeername(sock->rawFD(), (struct sockaddr *)&_addr, &addr_len);
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_is_udp = sock->sockType() == SockNum::Sock_UDP;
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if (_is_udp) {
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// 设置udp socket读缓存
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SockUtil::setRecvBuf(getSock()->rawFD(), 4 * 1024 * 1024);
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}
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}
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RtpSession::~RtpSession() {
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if(_process){
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RtpSelector::Instance().delProcess(_stream_id,_process.get());
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}
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}
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void RtpSession::onRecv(const Buffer::Ptr &data) {
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if (_is_udp) {
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onRtpPacket(data->data(), data->size());
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return;
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}
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RtpSplitter::input(data->data(), data->size());
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}
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void RtpSession::onError(const SockException &err) {
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WarnP(this) << _stream_id << " " << err;
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}
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void RtpSession::onManager() {
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if(_process && !_process->alive()){
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shutdown(SockException(Err_timeout, "receive rtp timeout"));
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}
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if(!_process && _ticker.createdTime() > 10 * 1000){
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shutdown(SockException(Err_timeout, "illegal connection"));
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}
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}
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void RtpSession::onRtpPacket(const char *data, size_t len) {
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if (_delay_close) {
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// 正在延时关闭中，忽略所有数据
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return;
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}
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if (!isRtp(data, len)) {
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// 忽略非rtp数据
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WarnP(this) << "Not rtp packet";
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return;
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}
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if (!_is_udp) {
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if (_search_rtp) {
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//搜索上下文期间，数据丢弃
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if (_search_rtp_finished) {
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//下个包开始就是正确的rtp包了
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_search_rtp_finished = false;
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_search_rtp = false;
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}
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return;
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}
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GET_CONFIG(uint32_t, rtpMaxSize, Rtp::kRtpMaxSize);
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if (len > 1024 * rtpMaxSize) {
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_search_rtp = true;
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WarnL << "rtp包长度异常(" << len << ")，发送端可能缓存溢出并覆盖，开始搜索ssrc以便恢复上下文";
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return;
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}
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}
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if (!_process) {
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//未设置ssrc时，尝试获取ssrc
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if (!_ssrc && !RtpSelector::getSSRC(data, len, _ssrc)) {
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return;
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}
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if (_stream_id.empty()) {
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//未指定流id就使用ssrc为流id
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_stream_id = printSSRC(_ssrc);
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}
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try {
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_process = RtpSelector::Instance().getProcess(_stream_id, true);
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} catch (RtpSelector::ProcessExisted &ex) {
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if (!_is_udp) {
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// tcp情况下立即断开连接
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throw;
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}
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// udp情况下延时断开连接(等待超时自动关闭)，防止频繁创建销毁RtpSession对象
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WarnP(this) << ex.what();
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_delay_close = true;
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return;
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}
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_process->setOnlyAudio(_only_audio);
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_process->setDelegate(static_pointer_cast<RtpSession>(shared_from_this()));
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}
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try {
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uint32_t rtp_ssrc = 0;
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RtpSelector::getSSRC(data, len, rtp_ssrc);
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if (rtp_ssrc != _ssrc) {
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WarnP(this) << "ssrc mismatched, rtp dropped: " << rtp_ssrc << " != " << _ssrc;
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return;
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}
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_process->inputRtp(false, getSock(), data, len, (struct sockaddr *)&_addr);
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} catch (RtpTrack::BadRtpException &ex) {
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if (!_is_udp) {
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WarnL << ex.what() << "，开始搜索ssrc以便恢复上下文";
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_search_rtp = true;
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} else {
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throw;
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}
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} catch (std::exception &ex) {
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if (!_is_udp) {
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// tcp情况下立即断开连接
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throw;
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}
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// udp情况下延时断开连接(等待超时自动关闭)，防止频繁创建销毁RtpSession对象
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WarnP(this) << ex.what();
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_delay_close = true;
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return;
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}
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_ticker.resetTime();
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}
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bool RtpSession::close(MediaSource &sender) {
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//此回调在其他线程触发
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string err = StrPrinter << "close media: " << sender.getUrl();
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safeShutdown(SockException(Err_shutdown, err));
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return true;
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}
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static const char *findSSRC(const char *data, ssize_t len, uint32_t ssrc) {
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//rtp前面必须预留两个字节的长度字段
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for (ssize_t i = 2; i <= len - 4; ++i) {
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auto ptr = (const uint8_t *) data + i;
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if (ptr[0] == (ssrc >> 24) && ptr[1] == ((ssrc >> 16) & 0xFF) &&
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ptr[2] == ((ssrc >> 8) & 0xFF) && ptr[3] == (ssrc & 0xFF)) {
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return (const char *) ptr;
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}
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}
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return nullptr;
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}
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static const char *findPsHeaderFlag(const char *data, ssize_t len) {
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for (ssize_t i = 2; i <= len - 4; ++i) {
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auto ptr = (const uint8_t *) data + i;
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//PsHeader 0x000001ba、PsSystemHeader0x000001bb（关键帧标识）
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if (ptr[0] == (0x00) && ptr[1] == (0x00) && ptr[2] == (0x01) && ptr[3] == (0xbb)) {
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return (const char *) ptr;
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}
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}
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return nullptr;
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}
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//rtp长度到ssrc间的长度固定为10
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static size_t constexpr kSSRCOffset = 2 + 4 + 4;
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// rtp长度到ps header间的长度固定为14 （暂时不采用找ps header,采用找system header代替）
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// rtp长度到ps system header间的长度固定为20 (关键帧标识)
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static size_t constexpr kPSHeaderOffset = 2 + 4 + 4 + 4 + 20;
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const char *RtpSession::onSearchPacketTail(const char *data, size_t len) {
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if (!_search_rtp) {
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//tcp上下文正常，不用搜索ssrc
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return RtpSplitter::onSearchPacketTail(data, len);
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}
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if (!_process) {
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InfoL << "ssrc未获取到，无法通过ssrc恢复tcp上下文；尝试搜索PsSystemHeader恢复tcp上下文。";
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auto rtp_ptr1 = searchByPsHeaderFlag(data,len);
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return rtp_ptr1;
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}
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auto rtp_ptr0 = searchBySSRC(data,len);
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if(rtp_ptr0) {
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return rtp_ptr0;
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}
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// ssrc搜索失败继续尝试搜索ps header flag
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auto rtp_ptr2 = searchByPsHeaderFlag(data,len);
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return rtp_ptr2;
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}
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const char *RtpSession::searchBySSRC(const char *data, size_t len) {
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InfoL << "尝试rtp搜索ssrc..._ssrc=" << _ssrc;
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//搜索第一个rtp的ssrc
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auto ssrc_ptr0 = findSSRC(data, len, _ssrc);
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if (!ssrc_ptr0) {
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//未搜索到任意rtp，返回数据不够
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InfoL << "rtp搜索ssrc失败（第一个数据不够），丢弃rtp数据为：" << len;
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return nullptr;
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}
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//这两个字节是第一个rtp的长度字段
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auto rtp_len_ptr = (ssrc_ptr0 - kSSRCOffset);
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auto rtp_len = ((uint8_t *)rtp_len_ptr)[0] << 8 | ((uint8_t *)rtp_len_ptr)[1];
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//搜索第二个rtp的ssrc
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auto ssrc_ptr1 = findSSRC(ssrc_ptr0 + rtp_len, data + (ssize_t) len - ssrc_ptr0 - rtp_len, _ssrc);
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if (!ssrc_ptr1) {
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//未搜索到第二个rtp，返回数据不够
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InfoL << "rtp搜索ssrc失败(第二个数据不够)，丢弃rtp数据为：" << len;
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return nullptr;
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}
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//两个ssrc的间隔正好等于rtp的长度(外加rtp长度字段)，那么说明找到rtp
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auto ssrc_offset = ssrc_ptr1 - ssrc_ptr0;
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if (ssrc_offset == rtp_len + 2 || ssrc_offset == rtp_len + 4) {
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InfoL << "rtp搜索ssrc成功，tcp上下文恢复成功，丢弃的rtp残余数据为：" << rtp_len_ptr - data;
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_search_rtp_finished = true;
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if (rtp_len_ptr == data) {
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//停止搜索rtp，否则会进入死循环
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_search_rtp = false;
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}
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//前面的数据都需要丢弃，这个是rtp的起始
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return rtp_len_ptr;
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}
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//第一个rtp长度不匹配，说明第一个找到的ssrc不是rtp，丢弃之，我们从第二个ssrc所在rtp开始搜索
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return ssrc_ptr1 - kSSRCOffset;
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}
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const char *RtpSession::searchByPsHeaderFlag(const char *data, size_t len) {
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InfoL << "尝试rtp搜索PsSystemHeaderFlag..._ssrc=" << _ssrc;
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// 搜索rtp中的第一个PsHeaderFlag
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auto ps_header_flag_ptr = findPsHeaderFlag(data,len);
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if (!ps_header_flag_ptr) {
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InfoL << "rtp搜索flag失败，丢弃rtp数据为：" << len;
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return nullptr;
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}
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auto rtp_ptr = ps_header_flag_ptr - kPSHeaderOffset;
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_search_rtp_finished = true;
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if (rtp_ptr == data) {
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//停止搜索rtp，否则会进入死循环
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_search_rtp = false;
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}
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InfoL << "rtp搜索flag成功，tcp上下文恢复成功，丢弃的rtp残余数据为：" << rtp_ptr - data;
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// TODO or Not ? 更新设置ssrc
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uint32_t rtp_ssrc = 0;
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RtpSelector::getSSRC(rtp_ptr+2, len, rtp_ssrc);
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_ssrc = rtp_ssrc;
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InfoL << "设置_ssrc为：" << _ssrc;
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// RtpServer::updateSSRC(uint32_t ssrc)
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return rtp_ptr;
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}
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}//namespace mediakit
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#endif//defined(ENABLE_RTPPROXY)
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