1）基础知识回顾

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2）各模块初始化

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新版本在mediasoup\worker\src\lib.cpp

  1. extern "C" int run_worker(
  2.   int argc,
  3.   char* argv[],
  4.   const char* version,
  5.   int consumerChannelFd,
  6.   int producerChannelFd,
  7.   int payloadConsumeChannelFd,
  8.   int payloadProduceChannelFd)
  9. {
  10.     // Initialize libuv stuff (we need it for the Channel).
  11.     DepLibUV::ClassInit();
  13.     // Channel socket. If Worker instance runs properly, this socket is closed by
  14.     // it in its destructor. Otherwise it's closed here by also letting libuv
  15.     // deallocate its UV handles.
  16.     std::unique_ptr<Channel::ChannelSocket> channel{ nullptr };
  18.     // PayloadChannel socket. If Worker instance runs properly, this socket is
  19.     // closed by it in its destructor. Otherwise it's closed here by also letting
  20.     // libuv deallocate its UV handles.
  21.     std::unique_ptr<PayloadChannel::PayloadChannelSocket> payloadChannel{ nullptr };
  23.     try
  24.     {
  25.         channel.reset(new Channel::ChannelSocket(consumerChannelFd, producerChannelFd));
  26.     }
  27.     catch (const MediaSoupError& error)
  28.     {
  29.         MS_ERROR_STD("error creating the Channel: %s", error.what());
  31.         DepLibUV::RunLoop();
  32.         DepLibUV::ClassDestroy();
  34.         return 1;
  35.     }
  37.     try
  38.     {
  39.         payloadChannel.reset(
  40.           new PayloadChannel::PayloadChannelSocket(payloadConsumeChannelFd, payloadProduceChannelFd));
  41.     }
  42.     catch (const MediaSoupError& error)
  43.     {
  44.         MS_ERROR_STD("error creating the RTC Channel: %s", error.what());
  46.         channel->Close();
  47.         DepLibUV::RunLoop();
  48.         DepLibUV::ClassDestroy();
  50.         return 1;
  51.     }
  53.     // Initialize the Logger.
  54.     Logger::ClassInit(channel.get());
  56.     try
  57.     {
  58.         Settings::SetConfiguration(argc, argv);
  59.     }
  60.     catch (const MediaSoupTypeError& error)
  61.     {
  62.         MS_ERROR_STD("settings error: %s", error.what());
  64.         channel->Close();
  65.         payloadChannel->Close();
  66.         DepLibUV::RunLoop();
  67.         DepLibUV::ClassDestroy();
  69.         // 42 is a custom exit code to notify "settings error" to the Node library.
  70.         return 42;
  71.     }
  72.     catch (const MediaSoupError& error)
  73.     {
  74.         MS_ERROR_STD("unexpected settings error: %s", error.what());
  76.         channel->Close();
  77.         payloadChannel->Close();
  78.         DepLibUV::RunLoop();
  79.         DepLibUV::ClassDestroy();
  81.         return 1;
  82.     }
  84.     MS_DEBUG_TAG(info, "starting mediasoup-worker process [version:%s]", version);
  86. #if defined(MS_LITTLE_ENDIAN)
  87.     MS_DEBUG_TAG(info, "little-endian CPU detected");
  88. #elif defined(MS_BIG_ENDIAN)
  89.     MS_DEBUG_TAG(info, "big-endian CPU detected");
  90. #else
  91.     MS_WARN_TAG(info, "cannot determine whether little-endian or big-endian");
  92. #endif
  94. #if defined(INTPTR_MAX) && defined(INT32_MAX) && (INTPTR_MAX == INT32_MAX)
  95.     MS_DEBUG_TAG(info, "32 bits architecture detected");
  96. #elif defined(INTPTR_MAX) && defined(INT64_MAX) && (INTPTR_MAX == INT64_MAX)
  97.     MS_DEBUG_TAG(info, "64 bits architecture detected");
  98. #else
  99.     MS_WARN_TAG(info, "cannot determine 32 or 64 bits architecture");
  100. #endif
  102.     Settings::PrintConfiguration();
  103.     DepLibUV::PrintVersion();
  105.     try
  106.     {
  107.         // Initialize static stuff.
  108.         DepOpenSSL::ClassInit();
  109.         DepLibSRTP::ClassInit();
  110.         DepUsrSCTP::ClassInit();
  111.         DepLibWebRTC::ClassInit();
  112.         Utils::Crypto::ClassInit();
  113.         RTC::DtlsTransport::ClassInit();
  114.         RTC::SrtpSession::ClassInit();
  115.         Channel::ChannelNotifier::ClassInit(channel.get());
  116.         PayloadChannel::PayloadChannelNotifier::ClassInit(payloadChannel.get());
  118. #ifdef MS_EXECUTABLE
  119.         // Ignore some signals.
  120.         IgnoreSignals();
  121. #endif
  123.         // Run the Worker.
  124.         Worker worker(channel.get(), payloadChannel.get());
  126.         // Free static stuff.
  127.         DepLibSRTP::ClassDestroy();
  128.         Utils::Crypto::ClassDestroy();
  129.         DepLibWebRTC::ClassDestroy();
  130.         RTC::DtlsTransport::ClassDestroy();
  131.         DepUsrSCTP::ClassDestroy();
  132.         DepLibUV::ClassDestroy();
  134. #ifdef MS_EXECUTABLE
  135.         // Wait a bit so pending messages to stdout/Channel arrive to the Node
  136.         // process.
  137.         uv_sleep(200);
  138. #endif
  140.         return 0;
  141.     }
  142.     catch (const MediaSoupError& error)
  143.     {
  144.         MS_ERROR_STD("failure exit: %s", error.what());
  146.         return 1;
  147.     }
  148. }

讲解各个初始化的函数

DepOpenSSL::ClassInit();

位置mediasoup\worker\src\DepOpenSSL.cpp

  1. void DepOpenSSL::ClassInit()
  2. {
  3.     MS_TRACE();
  5.     std::call_once(globalInitOnce, [] {
  6.         MS_DEBUG_TAG(info, "openssl version: \"%s\"", OpenSSL_version(OPENSSL_VERSION));
  8.         // Initialize some crypto stuff.
  9.         RAND_poll();
  10.     });
  11. }

DepLibSRTP::ClassInit();

位置mediasoup\worker\src\DepLibSRTP.cpp

  1. void DepLibSRTP::ClassInit()
  2. {
  3.     MS_TRACE();
  5.     {
  6.         std::lock_guard<std::mutex> lock(globalSyncMutex);
  8.         if (globalInstances == 0)
  9.         {
  10.             MS_DEBUG_TAG(info, "libsrtp version: \"%s\"", srtp_get_version_string());
  12.             srtp_err_status_t err = srtp_init();
  14.             if (DepLibSRTP::IsError(err))
  15.                 MS_THROW_ERROR("srtp_init() failed: %s", DepLibSRTP::GetErrorString(err));
  16.         }
  18.         ++globalInstances;
  19.     }
  20. }

DepUsrSCTP::ClassInit();

位置：mediasoup\worker\src\DepUsrSCTP.cpp

  1. void DepUsrSCTP::ClassInit()
  2. {
  3.     MS_TRACE();
  5.     MS_DEBUG_TAG(info, "usrsctp");
  7.     {
  8.         std::lock_guard<std::mutex> lock(globalSyncMutex);
  10.         if (globalInstances == 0)
  11.         {
  12.             usrsctp_init_nothreads(0, onSendSctpData, sctpDebug);
  14.             // Disable explicit congestion notifications (ecn).
  15.             usrsctp_sysctl_set_sctp_ecn_enable(0);
  17. #ifdef SCTP_DEBUG
  18.             usrsctp_sysctl_set_sctp_debug_on(SCTP_DEBUG_ALL);
  19. #endif
  20.         }
  22.         ++globalInstances;
  23.     }
  24. }

DepLibWebRTC::ClassInit();

位置：mediasoup\worker\src\DepLibWebRTC.cpp

  1. void DepLibWebRTC::ClassInit()
  2. {
  3.     MS_TRACE();
  5.     std::call_once(globalInitOnce, [] { webrtc::field_trial::InitFieldTrialsFromString(FieldTrials); });
  6. }

Utils::Crypto::ClassInit();

位置：mediasoup\worker\src\Utils\Crypto.cpp

  1. void Crypto::ClassInit()
  2.     {
  3.         MS_TRACE();
  5.         // Init the vrypto seed with a random number taken from the address
  6.         // of the seed variable itself (which is random).
  7.         Crypto::seed = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(std::addressof(Crypto::seed)));
  9.         // Create an OpenSSL HMAC_CTX context for HMAC SHA1 calculation.
  10.         Crypto::hmacSha1Ctx = HMAC_CTX_new();
  11.     }

RTC::DtlsTransport::ClassInit();

位置mediasoup\worker\src\RTC\DtlsTransport.cpp

  1. void DtlsTransport::ClassInit()
  2.     {
  3.         MS_TRACE();
  5.         // Generate a X509 certificate and private key (unless PEM files are provided).
  6.         if (
  7.           Settings::configuration.dtlsCertificateFile.empty() ||
  8.           Settings::configuration.dtlsPrivateKeyFile.empty())
  9.         {
  10.             GenerateCertificateAndPrivateKey();
  11.         }
  12.         else
  13.         {
  14.             ReadCertificateAndPrivateKeyFromFiles();
  15.         }
  17.         // Create a global SSL_CTX.
  18.         CreateSslCtx();
  20.         // Generate certificate fingerprints.
  21.         GenerateFingerprints();
  22.     }

RTC::SrtpSession::ClassInit();

位置：mediasoup\worker\src\RTC\SrtpSession.cpp

  1. void SrtpSession::ClassInit()
  2.     {
  3.         // Set libsrtp event handler.
  4.         srtp_err_status_t err =
  5.           srtp_install_event_handler(static_cast<srtp_event_handler_func_t*>(OnSrtpEvent));
  7.         if (DepLibSRTP::IsError(err))
  8.         {
  9.             MS_THROW_ERROR("srtp_install_event_handler() failed: %s", DepLibSRTP::GetErrorString(err));
  10.         }
  11.     }

Channel::ChannelNotifier::ClassInit(channel.get());

位置：mediasoup\worker\src\Channel\ChannelNotifier.cpp

  1.     void ChannelNotifier::ClassInit(Channel::ChannelSocket* channel)
  2.     {
  3.         MS_TRACE();
  5.         ChannelNotifier::channel = channel;
  6.     }

PayloadChannel::PayloadChannelNotifier::ClassInit(payloadChannel.get());

位置：mediasoup\worker\src\PayloadChannel\PayloadChannelNotifier.cpp

  1. void PayloadChannelNotifier::ClassInit(PayloadChannel::PayloadChannelSocket* payloadChannel)
  2. {
  3.     MS_TRACE();
  5.     PayloadChannelNotifier::payloadChannel = payloadChannel;
  6. }

3）传输处理申请
void Transport::HandleRequest(Channel::ChannelRequest* request)