Bumped version to 0.10.5

Change default data mid

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.7)
 project(libdatachannel
-	VERSION 0.10.0
+	VERSION 0.10.5
 	LANGUAGES CXX)
 set(PROJECT_DESCRIPTION "WebRTC Data Channels Library")
 
@@ -33,10 +33,11 @@ endif()
 
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/Modules)
+set(BUILD_SHARED_LIBS OFF) # to force usrsctp to be built static
 
 if(WIN32)
 	add_definitions(-DWIN32_LEAN_AND_MEAN)
-	if (MSVC)
+	if(MSVC)
 		add_definitions(-DNOMINMAX)
 		add_definitions(-D_CRT_SECURE_NO_WARNINGS)
 		add_definitions(-D_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING)
@@ -115,17 +116,15 @@ set(CMAKE_POLICY_DEFAULT_CMP0048 NEW)
 add_subdirectory(deps/plog)
 
 option(sctp_build_programs 0)
+option(sctp_build_shared_lib 0)
 add_subdirectory(deps/usrsctp EXCLUDE_FROM_ALL)
 if (MSYS OR MINGW)
 	target_compile_definitions(usrsctp PUBLIC -DSCTP_STDINT_INCLUDE=<stdint.h>)
-	target_compile_definitions(usrsctp-static PUBLIC -DSCTP_STDINT_INCLUDE=<stdint.h>)
 endif()
 if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
     target_compile_options(usrsctp PRIVATE -Wno-error=format-truncation)
-	target_compile_options(usrsctp-static PRIVATE -Wno-error=format-truncation)
 endif()
 add_library(Usrsctp::Usrsctp ALIAS usrsctp)
-add_library(Usrsctp::UsrsctpStatic ALIAS usrsctp-static)
 
 if (NO_WEBSOCKET)
 	add_library(datachannel SHARED
@@ -156,17 +155,17 @@ target_include_directories(datachannel PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/includ
 target_include_directories(datachannel PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include/rtc)
 target_include_directories(datachannel PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
 target_link_libraries(datachannel PUBLIC Threads::Threads plog::plog)
-target_link_libraries(datachannel PRIVATE Usrsctp::UsrsctpStatic)
+target_link_libraries(datachannel PRIVATE Usrsctp::Usrsctp)
 
 target_include_directories(datachannel-static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 target_include_directories(datachannel-static PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include/rtc)
 target_include_directories(datachannel-static PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
 target_link_libraries(datachannel-static PUBLIC Threads::Threads plog::plog)
-target_link_libraries(datachannel-static PRIVATE Usrsctp::UsrsctpStatic)
+target_link_libraries(datachannel-static PRIVATE Usrsctp::Usrsctp)
 
 if(WIN32)
-	target_link_libraries(datachannel PRIVATE ws2_32) # winsock2
+	target_link_libraries(datachannel PUBLIC ws2_32) # winsock2
-	target_link_libraries(datachannel-static PRIVATE ws2_32) # winsock2
+	target_link_libraries(datachannel-static PUBLIC ws2_32) # winsock2
 endif()
 
 if(NO_MEDIA)
@@ -274,11 +273,7 @@ if(NOT NO_TESTS)
 		set_target_properties(datachannel-tests PROPERTIES OUTPUT_NAME tests)
 	endif()
 	target_include_directories(datachannel-tests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
-	if(WIN32)
+	target_link_libraries(datachannel-tests datachannel)
-		target_link_libraries(datachannel-tests datachannel-static) # DLL exports only the C API
-	else()
-		target_link_libraries(datachannel-tests datachannel)
-	endif()
 
 	# Benchmark
 	add_executable(datachannel-benchmark test/benchmark.cpp)
@@ -290,11 +285,7 @@ if(NOT NO_TESTS)
 	endif()
 	target_compile_definitions(datachannel-benchmark PRIVATE BENCHMARK_MAIN=1)
 	target_include_directories(datachannel-benchmark PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
-	if(WIN32)
+	target_link_libraries(datachannel-benchmark datachannel)
-		target_link_libraries(datachannel-benchmark datachannel-static) # DLL exports only the C API
-	else()
-		target_link_libraries(datachannel-benchmark datachannel)
-	endif()
 endif()
 
 # Examples

Jamfile

@@ -15,9 +15,9 @@ lib libdatachannel
 	: # requirements
 	<cxxstd>17
 	<include>./include/rtc
-	<define>USE_NICE=0
 	<define>RTC_ENABLE_MEDIA=0
 	<define>RTC_ENABLE_WEBSOCKET=0
+	<define>USE_NICE=0
 	<toolset>msvc:<define>WIN32_LEAN_AND_MEAN
 	<toolset>msvc:<define>NOMINMAX
 	<toolset>msvc:<define>_CRT_SECURE_NO_WARNINGS
@@ -32,6 +32,8 @@ lib libdatachannel
 	<link>static
 	: # usage requirements
 	<include>./include
+	<define>RTC_ENABLE_MEDIA=0
+	<define>RTC_ENABLE_WEBSOCKET=0
 	<library>/libdatachannel//plog
 	<toolset>gcc:<cxxflags>"-pthread -Wno-pedantic -Wno-unused-parameter -Wno-unused-variable"
 	<toolset>clang:<cxxflags>"-pthread -Wno-pedantic -Wno-unused-parameter -Wno-unused-variable"
@@ -94,7 +96,7 @@ rule make_libusrsctp ( targets * : sources * : properties * )
 }
 actions make_libusrsctp
 {
-    (cd $(CWD)/deps/usrsctp && mkdir -p $(BUILD_DIR) && cd $(BUILD_DIR) && cmake -DCMAKE_BUILD_TYPE=$(VARIANT) -DCMAKE_C_FLAGS="-fPIC -Wno-unknown-warning-option -Wno-format-truncation" .. && make -j2 usrsctp-static)
+    (cd $(CWD)/deps/usrsctp && mkdir -p $(BUILD_DIR) && cd $(BUILD_DIR) && cmake -DCMAKE_BUILD_TYPE=$(VARIANT) -DCMAKE_C_FLAGS="-fPIC -Wno-unknown-warning-option -Wno-format-truncation" -Dsctp_build_shared_lib=0 -Dsctp_build_programs=0 .. && make -j2 usrsctp)
     cp $(CWD)/deps/usrsctp/$(BUILD_DIR)/usrsctplib/libusrsctp.a $(<)
 }
 rule make_libusrsctp_msvc ( targets * : sources * : properties * )
@@ -109,7 +111,7 @@ actions make_libusrsctp_msvc
     cd $(CWD)/deps/usrsctp
     mkdir $(BUILD_DIR)
     cd $(BUILD_DIR)
-    cmake -G "Visual Studio 16 2019" ..
+    cmake -G "Visual Studio 16 2019" -Dsctp_build_shared_lib=0 -Dsctp_build_programs=0 ..
     msbuild usrsctplib.sln /property:Configuration=$(VARIANT)
     cd %OLDD%
     cp $(CWD)/deps/usrsctp/$(BUILD_DIR)/usrsctplib/Release/usrsctp.lib $(<)

README.md

@@ -27,8 +27,9 @@ Features:
 - Full IPv6 support
 - Trickle ICE ([draft-ietf-ice-trickle-21](https://tools.ietf.org/html/draft-ietf-ice-trickle-21))
 - JSEP compatible ([draft-ietf-rtcweb-jsep-26](https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-26))
-- SRTP and SRTCP key derivation from DTLS ([RFC5764](https://tools.ietf.org/html/rfc5764))
 - Multicast DNS candidates ([draft-ietf-rtcweb-mdns-ice-candidates-04](https://tools.ietf.org/html/draft-ietf-rtcweb-mdns-ice-candidates-04))
+- SRTP and SRTCP key derivation from DTLS ([RFC5764](https://tools.ietf.org/html/rfc5764))
+- Differentiated Services QoS ([draft-ietf-tsvwg-rtcweb-qos-18](https://tools.ietf.org/html/draft-ietf-tsvwg-rtcweb-qos-18))
 - TURN relaying ([RFC5766](https://tools.ietf.org/html/rfc5766)) with [libnice](https://github.com/libnice/libnice) as ICE backend
 
 Note only SDP BUNDLE mode is supported for media multiplexing ([draft-ietf-mmusic-sdp-bundle-negotiation-54](https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-54)). The behavior is equivalent to the JSEP bundle-only policy: the library always negociates one unique network component, where SRTP media streams are multiplexed with SRTCP control packets ([RFC5761](https://tools.ietf.org/html/rfc5761)) and SCTP/DTLS data traffic ([RFC5764](https://tools.ietf.org/html/rfc5764)).

examples/client/CMakeLists.txt

@@ -9,14 +9,9 @@ target_compile_definitions(datachannel-client PUBLIC STATIC_GETOPT)
 else()
 add_executable(datachannel-client main.cpp parse_cl.cpp parse_cl.h)
 endif()
+
 set_target_properties(datachannel-client PROPERTIES
 	CXX_STANDARD 17
 	OUTPUT_NAME client)
-
-if(WIN32)
-	target_link_libraries(datachannel-client datachannel-static) # DLL exports only the C API
-else()
-	target_link_libraries(datachannel-client datachannel)
-endif()
 target_link_libraries(datachannel-client datachannel nlohmann_json)
 

examples/client/main.cpp

@@ -23,17 +23,18 @@
 
 #include "rtc/rtc.hpp"
 
+#include "parse_cl.h"
+
 #include <nlohmann/json.hpp>
 
 #include <algorithm>
+#include <future>
 #include <iostream>
 #include <memory>
 #include <random>
-#include <thread>
-#include <future>
 #include <stdexcept>
+#include <thread>
 #include <unordered_map>
-#include "parse_cl.h"
 
 using namespace rtc;
 using namespace std;
@@ -47,25 +48,23 @@ unordered_map<string, shared_ptr<PeerConnection>> peerConnectionMap;
 unordered_map<string, shared_ptr<DataChannel>> dataChannelMap;
 
 string localId;
-bool echoDataChannelMessages = false;
 
 shared_ptr<PeerConnection> createPeerConnection(const Configuration &config,
                                                 weak_ptr<WebSocket> wws, string id);
-void printReceived(bool echoed, string id, string type, size_t length);
 string randomId(size_t length);
 
-
 int main(int argc, char **argv) try {
 	auto params = std::make_unique<Cmdline>(argc, argv);
 
-	rtc::InitLogger(LogLevel::Debug);
+	rtc::InitLogger(LogLevel::Info);
 
 	Configuration config;
 	string stunServer = "";
 	if (params->noStun()) {
-		cout << "No STUN server is configured. Only local hosts and public IP addresses supported." << endl;
+		cout << "No STUN server is configured. Only local hosts and public IP addresses supported."
+		     << endl;
 	} else {
-		if (params->stunServer().substr(0,5).compare("stun:") != 0) {
+		if (params->stunServer().substr(0, 5).compare("stun:") != 0) {
 			stunServer = "stun:";
 		}
 		stunServer += params->stunServer() + ":" + to_string(params->stunPort());
@@ -76,27 +75,23 @@ int main(int argc, char **argv) try {
 	localId = randomId(4);
 	cout << "The local ID is: " << localId << endl;
 
-	echoDataChannelMessages = params->echoDataChannelMessages();
-	cout << "Received data channel messages will be "
-	     << (echoDataChannelMessages ? "echoed back to sender" : "printed to stdout") << endl;
-
 	auto ws = make_shared<WebSocket>();
 
 	std::promise<void> wsPromise;
 	auto wsFuture = wsPromise.get_future();
-	
+
-	ws->onOpen([&wsPromise]() { 
+	ws->onOpen([&wsPromise]() {
 		cout << "WebSocket connected, signaling ready" << endl;
 		wsPromise.set_value();
 	});
 
-	ws->onError([&wsPromise](string s) { 
+	ws->onError([&wsPromise](string s) {
 		cout << "WebSocket error" << endl;
 		wsPromise.set_exception(std::make_exception_ptr(std::runtime_error(s)));
 	});
-	
+
 	ws->onClosed([]() { cout << "WebSocket closed" << endl; });
-	
+
 	ws->onMessage([&](variant<binary, string> data) {
 		if (!holds_alternative<string>(data))
 			return;
@@ -134,14 +129,14 @@ int main(int argc, char **argv) try {
 	});
 
 	string wsPrefix = "";
-	if (params->webSocketServer().substr(0,5).compare("ws://") != 0) {
+	if (params->webSocketServer().substr(0, 5).compare("ws://") != 0) {
 		wsPrefix = "ws://";
 	}
 	const string url = wsPrefix + params->webSocketServer() + ":" +
-		to_string(params->webSocketPort()) + "/" + localId;
+	                   to_string(params->webSocketPort()) + "/" + localId;
 	cout << "Url is " << url << endl;
 	ws->open(url);
-	
+
 	cout << "Waiting for signaling to be connected..." << endl;
 	wsFuture.get();
 
@@ -171,20 +166,12 @@ int main(int argc, char **argv) try {
 
 		dc->onClosed([id]() { cout << "DataChannel from " << id << " closed" << endl; });
 
-		dc->onMessage([id, wdc = make_weak_ptr(dc)](const variant<binary, string> &message) {
+		dc->onMessage([id, wdc = make_weak_ptr(dc)](variant<binary, string> data) {
-			static bool firstMessage = true;
+			if (holds_alternative<string>(data))
-			if (holds_alternative<string>(message) && (!echoDataChannelMessages || firstMessage)) {
+				cout << "Message from " << id << " received: " << get<string>(data) << endl;
-				cout << "Message from " << id << " received: " << get<string>(message) << endl;
+			else
-				firstMessage = false;
+				cout << "Binary message from " << id
-			} else if (echoDataChannelMessages) {
+				     << " received, size=" << get<binary>(data).size() << endl;
-				bool echoed = false;
-				if (auto dc = wdc.lock()) {
-					dc->send(message);
-					echoed = true;
-				}
-				printReceived(echoed, id, (holds_alternative<string>(message) ? "text" : "binary"),
-				      get<string>(message).length());
-			}
 		});
 
 		dataChannelMap.emplace(id, dc);
@@ -237,20 +224,12 @@ shared_ptr<PeerConnection> createPeerConnection(const Configuration &config,
 
 		dc->onClosed([id]() { cout << "DataChannel from " << id << " closed" << endl; });
 
-		dc->onMessage([id, wdc = make_weak_ptr(dc)](const variant<binary, string> &message) {
+		dc->onMessage([id, wdc = make_weak_ptr(dc)](variant<binary, string> data) {
-			static bool firstMessage = true;
+			if (holds_alternative<string>(data))
-			if (holds_alternative<string>(message) && (!echoDataChannelMessages || firstMessage)) {
+				cout << "Message from " << id << " received: " << get<string>(data) << endl;
-				cout << "Message from " << id << " received: " << get<string>(message) << endl;
+			else
-				firstMessage = false;
+				cout << "Binary message from " << id
-			} else if (echoDataChannelMessages) {
+				     << " received, size=" << get<binary>(data).size() << endl;
-				bool echoed = false;
-				if (auto dc = wdc.lock()) {
-					dc->send(message);
-					echoed = true;
-				}
-				printReceived(echoed, id, (holds_alternative<string>(message) ? "text" : "binary"),
-						get<string>(message).length());
-			}
 		});
 
 		dc->send("Hello from " + localId);
@@ -262,20 +241,6 @@ shared_ptr<PeerConnection> createPeerConnection(const Configuration &config,
 	return pc;
 };
 
-// Helper function to print received pings
-void printReceived(bool echoed, string id, string type, size_t length) {
-	static long count = 0;
-	static long freq = 100;
-	if (!(++count%freq)) {
-		cout << "Received " << count << " pings in total from " << id << ", most recent of type "
-		     << type << " and " << (echoed ? "" : "un") << "successfully echoed most recent ping of size "
-		     << length << " back to " << id << endl;
-		if (count >= (freq * 10) && freq < 1000000) {
-			freq *= 10;
-		}
-	}
-}
-
 // Helper function to generate a random ID
 string randomId(size_t length) {
 	static const string characters(

examples/client/parse_cl.cpp

@@ -43,47 +43,39 @@ Cmdline::Cmdline (int argc, char *argv[]) // ISO C++17 not allowed: throw (std::
 
   static struct option long_options[] =
   {
-    {"echo", no_argument, NULL, 'e'},
     {"noStun", no_argument, NULL, 'n'},
     {"stunServer", required_argument, NULL, 's'},
     {"stunPort", required_argument, NULL, 't'},
     {"webSocketServer", required_argument, NULL, 'w'},
     {"webSocketPort", required_argument, NULL, 'x'},
     {"help", no_argument, NULL, 'h'},
-    {"version", no_argument, NULL, 'v'},
     {NULL, 0, NULL, 0}
   };
 
   _program_name += argv[0];
 
   /* default values */
-  _e = false;
   _n = false;
   _s = "stun.l.google.com";
   _t = 19302;
   _w = "localhost";
   _x = 8000;
   _h = false;
-  _v = false;
 
   optind = 0;
   while ((c = getopt_long (argc, argv, "s:t:w:x:enhv", long_options, &optind)) != - 1)
     {
       switch (c)
         {
-        case 'e': 
+        case 'n':
-          _e = true;
-          break;
-
-        case 'n': 
           _n = true;
           break;
 
-        case 's': 
+        case 's':
           _s = optarg;
           break;
 
-        case 't': 
+        case 't':
           _t = atoi (optarg);
           if (_t < 0)
             {
@@ -99,11 +91,11 @@ Cmdline::Cmdline (int argc, char *argv[]) // ISO C++17 not allowed: throw (std::
             }
           break;
 
-        case 'w': 
+        case 'w':
           _w = optarg;
           break;
 
-        case 'x': 
+        case 'x':
           _x = atoi (optarg);
           if (_x < 0)
             {
@@ -119,16 +111,11 @@ Cmdline::Cmdline (int argc, char *argv[]) // ISO C++17 not allowed: throw (std::
             }
           break;
 
-        case 'h': 
+        case 'h':
           _h = true;
           this->usage (EXIT_SUCCESS);
           break;
 
-        case 'v': 
-          _v = true;
-          this->version (EXIT_SUCCESS);
-          break;
-
         default:
           this->usage (EXIT_FAILURE);
 
@@ -155,8 +142,6 @@ void Cmdline::usage (int status)
       std::cout << "\
 usage: " << _program_name << " [ -enstwxhv ] \n\
 libdatachannel client implementing WebRTC Data Channels with WebSocket signaling\n\
-   [ -e ] [ --echo ] (type=FLAG)\n\
-          Echo data channel messages back to sender rather than putting to stdout.\n\
    [ -n ] [ --noStun ] (type=FLAG)\n\
           Do NOT use a stun server (overrides -s and -t).\n\
    [ -s ] [ --stunServer ] (type=STRING, default=stun.l.google.com)\n\
@@ -168,15 +153,8 @@ libdatachannel client implementing WebRTC Data Channels with WebSocket signaling
    [ -x ] [ --webSocketPort ] (type=INTEGER, range=0...65535, default=8000)\n\
           Web socket server port.\n\
    [ -h ] [ --help ] (type=FLAG)\n\
-          Display this help and exit.\n\
+          Display this help and exit.\n";
-   [ -v ] [ --version ] (type=FLAG)\n\
-          Output version information and exit.\n";
     }
   exit (status);
 }
 
-void Cmdline::version (int status)
-{
-  std::cout << _program_name << " v0.5\n";
-  exit (status);
-}

examples/client/parse_cl.h

@@ -34,14 +34,12 @@ class Cmdline
 {
 private:
   /* parameters */
-  bool _e;
   bool _n;
   std::string _s;
   int _t;
   std::string _w;
   int _x;
   bool _h;
-  bool _v;
 
   /* other stuff to keep track of */
   std::string _program_name;
@@ -55,20 +53,15 @@ public:
   /* usage function */
   void usage (int status);
 
-  /* version function */
-  void version (int status);
-
   /* return next (non-option) parameter */
   int next_param () { return _optind; }
 
-  bool echoDataChannelMessages () const { return _e; }
   bool noStun () const { return _n; }
   std::string stunServer () const { return _s; }
   int stunPort () const { return _t; }
   std::string webSocketServer () const { return _w; }
   int webSocketPort () const { return _x; }
   bool h () const { return _h; }
-  bool v () const { return _v; }
 };
 
 #endif

examples/copy-paste-capi/answerer.c

@@ -137,7 +137,7 @@ int main(int argc, char **argv) {
 			size_t candidate_size = 0;
 
 			if (getline(&candidate, &candidate_size, stdin)) {
-				rtcAddRemoteCandidate(peer->pc, candidate, "0");
+				rtcAddRemoteCandidate(peer->pc, candidate, NULL);
 				free(candidate);
 
 			} else {

examples/copy-paste-capi/offerer.c

@@ -140,7 +140,7 @@ int main(int argc, char **argv) {
 			char *candidate = NULL;
 			size_t candidate_size = 0;
 			if (getline(&candidate, &candidate_size, stdin)) {
-				rtcAddRemoteCandidate(peer->pc, candidate, "0");
+				rtcAddRemoteCandidate(peer->pc, candidate, NULL);
 				free(candidate);
 
 			} else {

examples/copy-paste/CMakeLists.txt

@@ -4,19 +4,11 @@ add_executable(datachannel-copy-paste-offerer offerer.cpp)
 set_target_properties(datachannel-copy-paste-offerer PROPERTIES
 	CXX_STANDARD 17
 	OUTPUT_NAME offerer)
-if(WIN32)
+target_link_libraries(datachannel-copy-paste-offerer datachannel)
-	target_link_libraries(datachannel-copy-paste-offerer datachannel-static) # DLL exports only the C API
-else()
-	target_link_libraries(datachannel-copy-paste-offerer datachannel)
-endif()
 
 add_executable(datachannel-copy-paste-answerer answerer.cpp)
 set_target_properties(datachannel-copy-paste-answerer PROPERTIES
 	CXX_STANDARD 17
 	OUTPUT_NAME answerer)
-if(WIN32)
+target_link_libraries(datachannel-copy-paste-answerer datachannel)
-	target_link_libraries(datachannel-copy-paste-answerer datachannel-static) # DLL exports only the C API
-else()
-	target_link_libraries(datachannel-copy-paste-answerer datachannel)
-endif()
 

examples/media/CMakeLists.txt

@@ -4,11 +4,5 @@ add_executable(datachannel-media main.cpp)
 set_target_properties(datachannel-media PROPERTIES
         CXX_STANDARD 17
         OUTPUT_NAME media)
+target_link_libraries(datachannel-media datachannel nlohmann_json)
 
-if(WIN32)
-    target_link_libraries(datachannel-media datachannel-static) # DLL exports only the C API
-else()
-    target_link_libraries(datachannel-media datachannel)
-endif()
-
-target_link_libraries(datachannel-media datachannel nlohmann_json)

examples/sfu-media/CMakeLists.txt

@@ -4,12 +4,5 @@ add_executable(datachannel-sfu-media main.cpp)
 set_target_properties(datachannel-sfu-media PROPERTIES
 		CXX_STANDARD 17
 		OUTPUT_NAME sfu-media)
-
-if(WIN32)
-	target_link_libraries(datachannel-sfu-media datachannel-static) # DLL exports only the C API
-else()
-	target_link_libraries(datachannel-sfu-media datachannel)
-endif()
-
 target_link_libraries(datachannel-sfu-media datachannel nlohmann_json)
 

examples/web/script.js

@@ -59,6 +59,7 @@ function openSignaling(url) {
     ws.onmessage = (e) => {
       if(typeof(e.data) != 'string') return;
       const message = JSON.parse(e.data);
+      console.log(message);
       const { id, type } = message;
 
       let pc = peerConnectionMap[id];

include/rtc/candidate.hpp

@@ -25,7 +25,7 @@
 
 namespace rtc {
 
-class Candidate {
+class RTC_CPP_EXPORT Candidate {
 public:
 	enum class Family { Unresolved, Ipv4, Ipv6 };
 	enum class Type { Unknown, Host, ServerReflexive, PeerReflexive, Relayed };
@@ -40,35 +40,44 @@ public:
 	enum class ResolveMode { Simple, Lookup };
 	bool resolve(ResolveMode mode = ResolveMode::Simple);
 
+	Type type() const;
+	TransportType transportType() const;
+	uint32_t priority() const;
 	string candidate() const;
 	string mid() const;
 	operator string() const;
 
+	bool operator==(const Candidate &other) const;
+	bool operator!=(const Candidate &other) const;
+
 	bool isResolved() const;
 	Family family() const;
-	Type type() const;
-	TransportType transportType() const;
 	std::optional<string> address() const;
 	std::optional<uint16_t> port() const;
-	std::optional<uint32_t> priority() const;
 
 private:
-	string mCandidate;
+	void parse(string candidate);
+
+	string mFoundation;
+	uint32_t mComponent, mPriority;
+	string mTypeString, mTransportString;
+	Type mType;
+	TransportType mTransportType;
+	string mNode, mService;
+	string mTail;
+
 	std::optional<string> mMid;
 
 	// Extracted on resolution
 	Family mFamily;
-	Type mType;
-	TransportType mTransportType;
 	string mAddress;
 	uint16_t mPort;
-	uint32_t mPriority;
 };
 
 } // namespace rtc
 
-std::ostream &operator<<(std::ostream &out, const rtc::Candidate &candidate);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, const rtc::Candidate &candidate);
-std::ostream &operator<<(std::ostream &out, const rtc::Candidate::Type &type);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, const rtc::Candidate::Type &type);
-std::ostream &operator<<(std::ostream &out, const rtc::Candidate::TransportType &transportType);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, const rtc::Candidate::TransportType &transportType);
 
 #endif

include/rtc/channel.hpp

@@ -28,13 +28,14 @@
 
 namespace rtc {
 
-class Channel {
+class RTC_CPP_EXPORT Channel {
 public:
 	Channel() = default;
 	virtual ~Channel() = default;
 
 	virtual void close() = 0;
 	virtual bool send(message_variant data) = 0; // returns false if buffered
+	virtual bool send(const byte *data, size_t size) = 0;
 
 	virtual bool isOpen() const = 0;
 	virtual bool isClosed() const = 0;

include/rtc/configuration.hpp

@@ -26,7 +26,7 @@
 
 namespace rtc {
 
-struct IceServer {
+struct RTC_CPP_EXPORT IceServer {
 	enum class Type { Stun, Turn };
 	enum class RelayType { TurnUdp, TurnTcp, TurnTls };
 
@@ -51,7 +51,7 @@ struct IceServer {
 	RelayType relayType;
 };
 
-struct ProxyServer {
+struct RTC_CPP_EXPORT ProxyServer {
 	enum class Type { None = 0, Socks5, Http, Last = Http };
 
 	ProxyServer(Type type_, string ip_, uint16_t port_, string username_ = "",
@@ -64,7 +64,7 @@ struct ProxyServer {
 	string password;
 };
 
-struct Configuration {
+struct RTC_CPP_EXPORT Configuration {
 	std::vector<IceServer> iceServers;
 	std::optional<ProxyServer> proxyServer;
 	bool enableIceTcp = false;

include/rtc/datachannel.hpp

@@ -36,7 +36,7 @@ namespace rtc {
 class SctpTransport;
 class PeerConnection;
 
-class DataChannel : public std::enable_shared_from_this<DataChannel>, public Channel {
+class RTC_CPP_EXPORT DataChannel : public std::enable_shared_from_this<DataChannel>, public Channel {
 public:
 	DataChannel(std::weak_ptr<PeerConnection> pc, uint16_t stream, string label, string protocol,
 	            Reliability reliability);
@@ -50,7 +50,7 @@ public:
 
 	void close(void) override;
 	bool send(message_variant data) override;
-	bool send(const byte *data, size_t size);
+	bool send(const byte *data, size_t size) override;
 	template <typename Buffer> bool sendBuffer(const Buffer &buf);
 	template <typename Iterator> bool sendBuffer(Iterator first, Iterator last);
 
@@ -87,7 +87,7 @@ private:
 	friend class PeerConnection;
 };
 
-class NegociatedDataChannel final : public DataChannel {
+class RTC_CPP_EXPORT NegociatedDataChannel final : public DataChannel {
 public:
 	NegociatedDataChannel(std::weak_ptr<PeerConnection> pc, uint16_t stream, string label,
 	                      string protocol, Reliability reliability);

include/rtc/description.hpp

@@ -32,7 +32,16 @@
 
 namespace rtc {
 
-class Description {
+const string DEFAULT_AUDIO_PROFILE =
+    "minptime=10;maxaveragebitrate=96000;stereo=1;sprop-stereo=1;useinbandfec=1";
+
+// Use Constrained Baseline profile Level 4.2 (necessary for Firefox)
+// https://developer.mozilla.org/en-US/docs/Web/Media/Formats/WebRTC_codecs#Supported_video_codecs
+// TODO: Should be 42E0 but 42C0 appears to be more compatible. Investigate this.
+const string DEFAULT_VIDEO_PROFILE =
+    "profile-level-id=42e01f;packetization-mode=1;level-asymmetry-allowed=1";
+
+class RTC_CPP_EXPORT Description {
 public:
 	enum class Type { Unspec, Offer, Answer, Pranswer, Rollback };
 	enum class Role { ActPass, Passive, Active };
@@ -53,6 +62,7 @@ public:
 	void hintType(Type type);
 	void setFingerprint(string fingerprint);
 
+	bool hasCandidate(const Candidate &candidate) const;
 	void addCandidate(Candidate candidate);
 	void addCandidates(std::vector<Candidate> candidates);
 	void endCandidates();
@@ -62,7 +72,7 @@ public:
 	string generateSdp(string_view eol) const;
 	string generateApplicationSdp(string_view eol) const;
 
-	class Entry {
+	class RTC_CPP_EXPORT Entry {
 	public:
 		virtual ~Entry() = default;
 
@@ -94,7 +104,7 @@ public:
 		Direction mDirection;
 	};
 
-	struct Application : public Entry {
+	struct RTC_CPP_EXPORT Application : public Entry {
 	public:
 		Application(string mid = "data");
 		virtual ~Application() = default;
@@ -119,7 +129,7 @@ public:
 	};
 
 	// Media (non-data)
-	class Media : public Entry {
+	class RTC_CPP_EXPORT Media : public Entry {
 	public:
 		Media(const string &sdp);
 		Media(const string &mline, string mid, Direction dir = Direction::SendOnly);
@@ -130,9 +140,10 @@ public:
 
 		void removeFormat(const string &fmt);
 
-		void addSSRC(uint32_t ssrc, std::string name);
+		void addSSRC(uint32_t ssrc, std::optional<string> name,
-		void addSSRC(uint32_t ssrc);
+		             std::optional<string> msid = nullopt);
-		void replaceSSRC(uint32_t oldSSRC, uint32_t ssrc, string name);
+		void replaceSSRC(uint32_t oldSSRC, uint32_t ssrc, std::optional<string> name,
+		                 std::optional<string> msid = nullopt);
 		bool hasSSRC(uint32_t ssrc);
 		std::vector<uint32_t> getSSRCs();
 
@@ -141,6 +152,9 @@ public:
 
 		bool hasPayloadType(int payloadType) const;
 
+		void addRTXCodec(unsigned int payloadType, unsigned int originalPayloadType,
+		                 unsigned int clockRate);
+
 		virtual void parseSdpLine(string_view line) override;
 
 		struct RTPMap {
@@ -149,7 +163,7 @@ public:
 
 			void removeFB(const string &string);
 			void addFB(const string &string);
-			void addAttribute(std::string attr) { fmtps.emplace_back(attr); }
+			void addAttribute(string attr) { fmtps.emplace_back(std::move(attr)); }
 
 			int pt;
 			string format;
@@ -180,21 +194,27 @@ public:
 
 	public:
 		void addRTPMap(const RTPMap &map);
+
+		void removeSSRC(uint32_t oldSSRC);
 	};
 
-	class Audio : public Media {
+	class RTC_CPP_EXPORT Audio : public Media {
 	public:
 		Audio(string mid = "audio", Direction dir = Direction::SendOnly);
 
-		void addAudioCodec(int payloadType, const string &codec);
+		void addAudioCodec(int payloadType, string codec,
+		                   std::optional<string> profile = DEFAULT_AUDIO_PROFILE);
+
 		void addOpusCodec(int payloadType);
 	};
 
-	class Video : public Media {
+	class RTC_CPP_EXPORT Video : public Media {
 	public:
 		Video(string mid = "video", Direction dir = Direction::SendOnly);
 
-		void addVideoCodec(int payloadType, const string &codec);
+		void addVideoCodec(int payloadType, string codec,
+		                   std::optional<string> profile = DEFAULT_VIDEO_PROFILE);
+
 		void addH264Codec(int payloadType);
 		void addVP8Codec(int payloadType);
 		void addVP9Codec(int payloadType);
@@ -244,8 +264,8 @@ private:
 
 } // namespace rtc
 
-std::ostream &operator<<(std::ostream &out, const rtc::Description &description);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, const rtc::Description &description);
-std::ostream &operator<<(std::ostream &out, rtc::Description::Type type);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, rtc::Description::Type type);
-std::ostream &operator<<(std::ostream &out, rtc::Description::Role role);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, rtc::Description::Role role);
 
 #endif

include/rtc/include.hpp

@@ -28,9 +28,15 @@
 #endif
 
 #ifdef _WIN32
+#define RTC_CPP_EXPORT __declspec(dllexport)
 #ifndef _WIN32_WINNT
 #define _WIN32_WINNT 0x0602 // Windows 8
 #endif
+#ifdef _MSC_VER
+#pragma warning(disable:4251) // disable "X needs to have dll-interface..."
+#endif
+#else
+#define RTC_CPP_EXPORT
 #endif
 
 #include "log.hpp"
@@ -102,12 +108,12 @@ private:
 	std::function<void()> function;
 };
 
-template <typename... P> class synchronized_callback {
+template <typename... Args> class synchronized_callback {
 public:
 	synchronized_callback() = default;
 	synchronized_callback(synchronized_callback &&cb) { *this = std::move(cb); }
 	synchronized_callback(const synchronized_callback &cb) { *this = cb; }
-	synchronized_callback(std::function<void(P...)> func) { *this = std::move(func); }
+	synchronized_callback(std::function<void(Args...)> func) { *this = std::move(func); }
 	~synchronized_callback() { *this = nullptr; }
 
 	synchronized_callback &operator=(synchronized_callback &&cb) {
@@ -123,16 +129,16 @@ public:
 		return *this;
 	}
 
-	synchronized_callback &operator=(std::function<void(P...)> func) {
+	synchronized_callback &operator=(std::function<void(Args...)> func) {
 		std::lock_guard lock(mutex);
 		callback = std::move(func);
 		return *this;
 	}
 
-	void operator()(P... args) const {
+	void operator()(Args... args) const {
 		std::lock_guard lock(mutex);
 		if (callback)
-			callback(args...);
+			callback(std::move(args)...);
 	}
 
 	operator bool() const {
@@ -140,8 +146,12 @@ public:
 		return callback ? true : false;
 	}
 
+	std::function<void(Args...)> wrap() const {
+		return [this](Args... args) { (*this)(std::move(args)...); };
+	}
+
 private:
-	std::function<void(P...)> callback;
+	std::function<void(Args...)> callback;
 	mutable std::recursive_mutex mutex;
 };
 } // namespace rtc

include/rtc/init.hpp

@@ -27,7 +27,7 @@ namespace rtc {
 
 using init_token = std::shared_ptr<void>;
 
-class Init {
+class RTC_CPP_EXPORT Init {
 public:
 	static init_token Token();
 	static void Preload();

include/rtc/log.hpp

@@ -35,6 +35,8 @@
 #pragma warning(pop)
 #endif
 
+#include "include.hpp"
+
 namespace rtc {
 
 enum class LogLevel { // Don't change, it must match plog severity
@@ -47,8 +49,8 @@ enum class LogLevel { // Don't change, it must match plog severity
 	Verbose = 6
 };
 
-void InitLogger(LogLevel level);
+RTC_CPP_EXPORT void InitLogger(LogLevel level);
-void InitLogger(plog::Severity severity, plog::IAppender *appender = nullptr);
+RTC_CPP_EXPORT void InitLogger(plog::Severity severity, plog::IAppender *appender = nullptr);
 } // namespace rtc
 
 #endif

include/rtc/message.hpp

@@ -29,7 +29,7 @@
 
 namespace rtc {
 
-struct Message : binary {
+struct RTC_CPP_EXPORT Message : binary {
 	enum Type { Binary, String, Control, Reset };
 
 	Message(const Message &message) = default;
@@ -42,7 +42,8 @@ struct Message : binary {
 	Message(binary &&data, Type type_ = Binary) : binary(std::move(data)), type(type_) {}
 
 	Type type;
-	unsigned int stream = 0;
+	unsigned int stream = 0; // Stream id (SCTP stream or SSRC)
+	unsigned int dscp = 0;   // Differentiated Services Code Point
 	std::shared_ptr<Reliability> reliability;
 };
 

include/rtc/peerconnection.hpp

@@ -50,14 +50,14 @@ class SctpTransport;
 using certificate_ptr = std::shared_ptr<Certificate>;
 using future_certificate_ptr = std::shared_future<certificate_ptr>;
 
-struct DataChannelInit {
+struct RTC_CPP_EXPORT DataChannelInit {
 	Reliability reliability = {};
 	bool negotiated = false;
 	std::optional<uint16_t> id = nullopt;
 	string protocol = "";
 };
 
-class PeerConnection final : public std::enable_shared_from_this<PeerConnection> {
+class RTC_CPP_EXPORT PeerConnection final : public std::enable_shared_from_this<PeerConnection> {
 public:
 	enum class State : int {
 		New = RTC_NEW,
@@ -129,7 +129,7 @@ public:
 	void onTrack(std::function<void(std::shared_ptr<Track> track)> callback);
 
 private:
-	std::shared_ptr<IceTransport> initIceTransport(Description::Role role);
+	std::shared_ptr<IceTransport> initIceTransport();
 	std::shared_ptr<DtlsTransport> initDtlsTransport();
 	std::shared_ptr<SctpTransport> initSctpTransport();
 	void closeTransports();
@@ -157,6 +157,8 @@ private:
 	void processLocalCandidate(Candidate candidate);
 	void processRemoteDescription(Description description);
 	void processRemoteCandidate(Candidate candidate);
+	string localBundleMid() const;
+
 	void triggerDataChannel(std::weak_ptr<DataChannel> weakDataChannel);
 	void triggerTrack(std::shared_ptr<Track> track);
 	bool changeState(State state);
@@ -203,8 +205,8 @@ private:
 
 } // namespace rtc
 
-std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::State state);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::State state);
-std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::GatheringState state);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::GatheringState state);
-std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::SignalingState state);
+RTC_CPP_EXPORT std::ostream &operator<<(std::ostream &out, rtc::PeerConnection::SignalingState state);
 
 #endif

include/rtc/rtcp.hpp

@@ -29,7 +29,7 @@
 
 namespace rtc {
 
-class RtcpHandler {
+class RTC_CPP_EXPORT RtcpHandler {
 protected:
 	/**
 	 * Use this callback when trying to send custom data (such as RTCP) to the client.
@@ -64,7 +64,7 @@ public:
 class Track;
 
 // An RtcpSession can be plugged into a Track to handle the whole RTCP session
-class RtcpReceivingSession : public RtcpHandler {
+class RTC_CPP_EXPORT RtcpReceivingSession : public RtcpHandler {
 public:
 	rtc::message_ptr incoming(rtc::message_ptr ptr) override;
 	rtc::message_ptr outgoing(rtc::message_ptr ptr) override;

include/rtc/rtp.hpp

@@ -20,7 +20,7 @@
 #ifndef RTC_RTP_HPP
 #define RTC_RTP_HPP
 
-#include <rtc/log.hpp>
+#include "log.hpp"
 
 #include <cmath>
 
@@ -57,6 +57,7 @@ public:
 
 	inline uint8_t version() const { return _first >> 6; }
 	inline bool padding() const { return (_first >> 5) & 0x01; }
+	inline bool extension() const { return (_first >> 4) & 0x01; }
 	inline uint8_t csrcCount() const { return _first & 0x0F; }
 	inline uint8_t marker() const { return _payloadType & 0b10000000; }
 	inline uint8_t payloadType() const { return _payloadType & 0b01111111; }
@@ -65,18 +66,32 @@ public:
 	inline uint32_t ssrc() const { return ntohl(_ssrc); }
 
 	inline size_t getSize() const {
-		return ((char *)&csrc) - ((char *)this) + sizeof(SSRC) * csrcCount();
+		return reinterpret_cast<const char *>(&csrc) - reinterpret_cast<const char *>(this) +
+		       sizeof(SSRC) * csrcCount();
 	}
 
-	char *getBody() const { return ((char *)&csrc) + sizeof(SSRC) * csrcCount(); }
+	[[nodiscard]] char *getBody() {
+		return reinterpret_cast<char *>(&csrc) + sizeof(SSRC) * csrcCount();
+	}
+
+	[[nodiscard]] const char *getBody() const {
+		return reinterpret_cast<const char *>(&csrc) + sizeof(SSRC) * csrcCount();
+	}
 
 	inline void setSeqNumber(uint16_t newSeqNo) { _seqNumber = htons(newSeqNo); }
 	inline void setPayloadType(uint8_t newPayloadType) {
 		_payloadType = (_payloadType & 0b10000000u) | (0b01111111u & newPayloadType);
 	}
-	inline void setSsrc(uint32_t ssrc) { _ssrc = htonl(ssrc); }
+	inline void setSsrc(uint32_t in_ssrc) { _ssrc = htonl(in_ssrc); }
 
 	void setTimestamp(uint32_t i) { _timestamp = htonl(i); }
+
+	void log() {
+		PLOG_VERBOSE << "RTP V: " << (int)version() << " P: " << (padding() ? "P" : " ")
+		             << " X: " << (extension() ? "X" : " ") << " CC: " << (int)csrcCount()
+		             << " M: " << (marker() ? "M" : " ") << " PT: " << (int)payloadType()
+		             << " SEQNO: " << seqNumber() << " TS: " << timestamp();
+	}
 };
 
 struct RTCP_ReportBlock {
@@ -91,13 +106,13 @@ private:
 	uint32_t _delaySinceLastReport;
 
 public:
-	inline void preparePacket(SSRC ssrc, [[maybe_unused]] unsigned int packetsLost,
+	inline void preparePacket(SSRC in_ssrc, [[maybe_unused]] unsigned int packetsLost,
 	                          [[maybe_unused]] unsigned int totalPackets, uint16_t highestSeqNo,
 	                          uint16_t seqNoCycles, uint32_t jitter, uint64_t lastSR_NTP,
 	                          uint64_t lastSR_DELAY) {
 		setSeqNo(highestSeqNo, seqNoCycles);
 		setJitter(jitter);
-		setSSRC(ssrc);
+		setSSRC(in_ssrc);
 
 		// Middle 32 bits of NTP Timestamp
 		//		  this->lastReport = lastSR_NTP >> 16u;
@@ -105,22 +120,23 @@ public:
 		setDelaySinceSR(uint32_t(lastSR_DELAY));
 
 		// The delay, expressed in units of 1/65536 seconds
-		//		  this->delaySinceLastReport = lastSR_DELAY;
+		// this->delaySinceLastReport = lastSR_DELAY;
 	}
 
-	inline void setSSRC(SSRC ssrc) { this->ssrc = htonl(ssrc); }
+	inline void setSSRC(SSRC in_ssrc) { this->ssrc = htonl(in_ssrc); }
-	inline SSRC getSSRC() const { return ntohl(ssrc); }
+	[[nodiscard]] inline SSRC getSSRC() const { return ntohl(ssrc); }
 
 	inline void setPacketsLost([[maybe_unused]] unsigned int packetsLost,
 	                           [[maybe_unused]] unsigned int totalPackets) {
 		// TODO Implement loss percentages.
 		_fractionLostAndPacketsLost = 0;
 	}
-	inline unsigned int getLossPercentage() const {
+
+	[[nodiscard]] inline unsigned int getLossPercentage() const {
 		// TODO Implement loss percentages.
 		return 0;
 	}
-	inline unsigned int getPacketLostCount() const {
+	[[nodiscard]] inline unsigned int getPacketLostCount() const {
 		// TODO Implement total packets lost.
 		return 0;
 	}
@@ -137,13 +153,13 @@ public:
 	inline void setJitter(uint32_t jitter) { _jitter = htonl(jitter); }
 
 	inline void setNTPOfSR(uint64_t ntp) { _lastReport = htonll(ntp >> 16u); }
-	inline uint32_t getNTPOfSR() const { return ntohl(_lastReport) << 16u; }
+	[[nodiscard]] inline uint32_t getNTPOfSR() const { return ntohl(_lastReport) << 16u; }
 
 	inline void setDelaySinceSR(uint32_t sr) {
 		// The delay, expressed in units of 1/65536 seconds
 		_delaySinceLastReport = htonl(sr);
 	}
-	inline uint32_t getDelaySinceSR() const { return ntohl(_delaySinceLastReport); }
+	[[nodiscard]] inline uint32_t getDelaySinceSR() const { return ntohl(_delaySinceLastReport); }
 
 	inline void log() const {
 		PLOG_VERBOSE << "RTCP report block: "
@@ -187,9 +203,9 @@ public:
 
 	inline void log() const {
 		PLOG_VERBOSE << "RTCP header: "
-		          << "version=" << unsigned(version()) << ", padding=" << padding()
+		             << "version=" << unsigned(version()) << ", padding=" << padding()
-		          << ", reportCount=" << unsigned(reportCount())
+		             << ", reportCount=" << unsigned(reportCount())
-		          << ", payloadType=" << unsigned(payloadType()) << ", length=" << length();
+		             << ", payloadType=" << unsigned(payloadType()) << ", length=" << length();
 	}
 };
 
@@ -234,8 +250,10 @@ public:
 		this->_senderSSRC = htonl(senderSSRC);
 	}
 
-	inline RTCP_ReportBlock *getReportBlock(int num) { return &_reportBlocks + num; }
+	[[nodiscard]] inline RTCP_ReportBlock *getReportBlock(int num) { return &_reportBlocks + num; }
-	inline const RTCP_ReportBlock *getReportBlock(int num) const { return &_reportBlocks + num; }
+	[[nodiscard]] inline const RTCP_ReportBlock *getReportBlock(int num) const {
+		return &_reportBlocks + num;
+	}
 
 	[[nodiscard]] inline size_t getSize() const {
 		// "length" in packet is one less than the number of 32 bit words in the packet.
@@ -272,8 +290,10 @@ private:
 	RTCP_ReportBlock _reportBlocks;
 
 public:
-	inline RTCP_ReportBlock *getReportBlock(int num) { return &_reportBlocks + num; }
+	[[nodiscard]] inline RTCP_ReportBlock *getReportBlock(int num) { return &_reportBlocks + num; }
-	inline const RTCP_ReportBlock *getReportBlock(int num) const { return &_reportBlocks + num; }
+	[[nodiscard]] inline const RTCP_ReportBlock *getReportBlock(int num) const {
+		return &_reportBlocks + num;
+	}
 
 	inline SSRC senderSSRC() const { return ntohl(_senderSSRC); }
 	inline void setSenderSSRC(SSRC ssrc) { this->_senderSSRC = htonl(ssrc); }
@@ -325,7 +345,7 @@ struct RTCP_REMB {
 		return sizeof(uint32_t) * (1 + header.header.length());
 	}
 
-	void preparePacket(SSRC senderSSRC, unsigned int numSSRC, unsigned int bitrate) {
+	void preparePacket(SSRC senderSSRC, unsigned int numSSRC, unsigned int in_bitrate) {
 
 		// Report Count becomes the format here.
 		header.header.prepareHeader(206, 15, 0);
@@ -340,21 +360,21 @@ struct RTCP_REMB {
 		id[2] = 'M';
 		id[3] = 'B';
 
-		setBitrate(numSSRC, bitrate);
+		setBitrate(numSSRC, in_bitrate);
 	}
 
-	void setBitrate(unsigned int numSSRC, unsigned int bitrate) {
+	void setBitrate(unsigned int numSSRC, unsigned int in_bitrate) {
 		unsigned int exp = 0;
-		while (bitrate > pow(2, 18) - 1) {
+		while (in_bitrate > pow(2, 18) - 1) {
 			exp++;
-			bitrate /= 2;
+			in_bitrate /= 2;
 		}
 
 		// "length" in packet is one less than the number of 32 bit words in the packet.
 		header.header.setLength(
 		    uint16_t((offsetof(RTCP_REMB, ssrc) / sizeof(uint32_t)) - 1 + numSSRC));
 
-		this->bitrate = htonl((numSSRC << (32u - 8u)) | (exp << (32u - 8u - 6u)) | bitrate);
+		this->bitrate = htonl((numSSRC << (32u - 8u)) | (exp << (32u - 8u - 6u)) | in_bitrate);
 	}
 
 	void setSsrc(int iterator, SSRC newSssrc) { ssrc[iterator] = htonl(newSssrc); }
@@ -416,7 +436,7 @@ public:
 
 public:
 	void preparePacket(SSRC ssrc, unsigned int discreteSeqNoCount) {
-		header.header.prepareHeader(205, 1, 2 + discreteSeqNoCount);
+		header.header.prepareHeader(205, 1, 2 + uint16_t(discreteSeqNoCount));
 		header.setMediaSourceSSRC(ssrc);
 		header.setPacketSenderSSRC(ssrc);
 	}
@@ -469,11 +489,15 @@ public:
 		return ntohs(*(uint16_t *)(header.getBody()));
 	}
 
-	char *getBody() { return header.getBody() + sizeof(uint16_t); }
+	[[nodiscard]] char *getBody() { return header.getBody() + sizeof(uint16_t); }
 
-	size_t getBodySize(size_t totalSize) { return totalSize - ((char *)getBody() - (char *)this); }
+	[[nodiscard]] const char *getBody() const { return header.getBody() + sizeof(uint16_t); }
 
-	RTP &getHeader() { return header; }
+	[[nodiscard]] size_t getBodySize(size_t totalSize) {
+		return totalSize - (getBody() - reinterpret_cast<char *>(this));
+	}
+
+	[[nodiscard]] RTP &getHeader() { return header; }
 
 	size_t normalizePacket(size_t totalSize, SSRC originalSSRC, uint8_t originalPayloadType) {
 		header.setSeqNumber(getOriginalSeqNo());

include/rtc/track.hpp

@@ -35,7 +35,7 @@ namespace rtc {
 class DtlsSrtpTransport;
 #endif
 
-class Track final : public std::enable_shared_from_this<Track>, public Channel {
+class RTC_CPP_EXPORT Track final : public std::enable_shared_from_this<Track>, public Channel {
 public:
 	Track(Description::Media description);
 	~Track() = default;
@@ -47,7 +47,7 @@ public:
 
 	void close(void) override;
 	bool send(message_variant data) override;
-	bool send(const byte *data, size_t size);
+	bool send(const byte *data, size_t size) override;
 
 	bool isOpen(void) const override;
 	bool isClosed(void) const override;
@@ -70,8 +70,8 @@ private:
 	std::weak_ptr<DtlsSrtpTransport> mDtlsSrtpTransport;
 #endif
 
-	bool outgoing(message_ptr message);
 	void incoming(message_ptr message);
+	bool outgoing(message_ptr message);
 
 	Description::Media mMediaDescription;
 	std::atomic<bool> mIsClosed = false;

include/rtc/websocket.hpp

@@ -38,7 +38,7 @@ class TcpTransport;
 class TlsTransport;
 class WsTransport;
 
-class WebSocket final : public Channel, public std::enable_shared_from_this<WebSocket> {
+class RTC_CPP_EXPORT WebSocket final : public Channel, public std::enable_shared_from_this<WebSocket> {
 public:
 	enum class State : int {
 		Connecting = 0,
@@ -49,6 +49,7 @@ public:
 
 	struct Configuration {
 		bool disableTlsVerification = false; // if true, don't verify the TLS certificate
+		std::vector<string> protocols;
 	};
 
 	WebSocket(std::optional<Configuration> config = nullopt);
@@ -59,6 +60,7 @@ public:
 	void open(const string &url);
 	void close() override;
 	bool send(const message_variant data) override;
+	bool send(const byte *data, size_t size) override;
 
 	bool isOpen() const override;
 	bool isClosed() const override;

src/candidate.cpp

@@ -20,6 +20,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cctype>
 #include <sstream>
 #include <unordered_map>
 
@@ -39,39 +40,44 @@ using std::string;
 
 namespace {
 
-inline bool hasprefix(const string &str, const string &prefix) {
+inline bool match_prefix(const string &str, const string &prefix) {
 	return str.size() >= prefix.size() &&
 	       std::mismatch(prefix.begin(), prefix.end(), str.begin()).first == prefix.end();
 }
 
+inline void trim_begin(string &str) {
+	str.erase(str.begin(),
+	          std::find_if(str.begin(), str.end(), [](char c) { return !std::isspace(c); }));
+}
+
+inline void trim_end(string &str) {
+	str.erase(
+	    std::find_if(str.rbegin(), str.rend(), [](char c) { return !std::isspace(c); }).base(),
+	    str.end());
+}
+
 } // namespace
 
 namespace rtc {
 
 Candidate::Candidate()
-    : mFamily(Family::Unresolved), mType(Type::Unknown), mTransportType(TransportType::Unknown),
+    : mFoundation("none"), mComponent(0), mPriority(0), mTypeString("unknown"),
-      mPort(0), mPriority(0) {}
+      mTransportString("unknown"), mType(Type::Unknown), mTransportType(TransportType::Unknown),
+      mNode("0.0.0.0"), mService("9"), mFamily(Family::Unresolved), mPort(0) {}
 
 Candidate::Candidate(string candidate) : Candidate() {
-	const std::array prefixes{"a=", "candidate:"};
+	if (!candidate.empty())
-	for (const string &prefix : prefixes)
+		parse(std::move(candidate));
-		if (hasprefix(candidate, prefix))
-			candidate.erase(0, prefix.size());
-
-	mCandidate = std::move(candidate);
 }
 
-Candidate::Candidate(string candidate, string mid) : Candidate(std::move(candidate)) {
+Candidate::Candidate(string candidate, string mid) : Candidate() {
+	if (!candidate.empty())
+		parse(std::move(candidate));
 	if (!mid.empty())
 		mMid.emplace(std::move(mid));
 }
 
-void Candidate::hintMid(string mid) {
+void Candidate::parse(string candidate) {
-	if (!mMid)
-		mMid.emplace(std::move(mid));
-}
-
-bool Candidate::resolve(ResolveMode mode) {
 	using TypeMap_t = std::unordered_map<string, Type>;
 	using TcpTypeMap_t = std::unordered_map<string, TransportType>;
 
@@ -84,99 +90,122 @@ bool Candidate::resolve(ResolveMode mode) {
 	                                        {"passive", TransportType::TcpPassive},
 	                                        {"so", TransportType::TcpSo}};
 
-	if (mFamily != Family::Unresolved)
+	const std::array prefixes{"a=", "candidate:"};
-		return true;
+	for (const string &prefix : prefixes)
+		if (match_prefix(candidate, prefix))
+			candidate.erase(0, prefix.size());
 
-	if (mCandidate.empty())
+	PLOG_VERBOSE << "Parsing candidate: " << candidate;
-		throw std::logic_error("Candidate is empty");
-
-	PLOG_VERBOSE << "Resolving candidate (mode="
-	             << (mode == ResolveMode::Simple ? "simple" : "lookup") << "): " << mCandidate;
 
 	// See RFC 8445 for format
-	std::istringstream iss(mCandidate);
+	std::istringstream iss(candidate);
-	int component{0}, priority{0};
+	string transport, typ_, type;
-	string foundation, transport, node, service, typ_, type;
+	if (!(iss >> mFoundation >> mComponent >> mTransportString >> mPriority &&
-	if (iss >> foundation >> component >> transport >> priority &&
+	      iss >> mNode >> mService >> typ_ >> mTypeString && typ_ == "typ"))
-	    iss >> node >> service >> typ_ >> type && typ_ == "typ") {
+		throw std::invalid_argument("Invalid candidate format");
 
-		string left;
+	std::getline(iss, mTail);
-		std::getline(iss, left);
+	trim_begin(mTail);
+	trim_end(mTail);
 
-		if (auto it = TypeMap.find(type); it != TypeMap.end())
+	if (auto it = TypeMap.find(type); it != TypeMap.end())
-			mType = it->second;
+		mType = it->second;
-		else
+	else
-			mType = Type::Unknown;
+		mType = Type::Unknown;
 
-		if (transport == "UDP" || transport == "udp") {
+	if (transport == "UDP" || transport == "udp") {
-			mTransportType = TransportType::Udp;
+		mTransportType = TransportType::Udp;
-		} else if (transport == "TCP" || transport == "tcp") {
+	} else if (transport == "TCP" || transport == "tcp") {
-			std::istringstream iss(left);
+		// Peek tail to find TCP type
-			string tcptype_, tcptype;
+		std::istringstream tiss(mTail);
-			if (iss >> tcptype_ >> tcptype && tcptype_ == "tcptype") {
+		string tcptype_, tcptype;
-				if (auto it = TcpTypeMap.find(tcptype); it != TcpTypeMap.end())
+		if (tiss >> tcptype_ >> tcptype && tcptype_ == "tcptype") {
-					mTransportType = it->second;
+			if (auto it = TcpTypeMap.find(tcptype); it != TcpTypeMap.end())
-				else
+				mTransportType = it->second;
-					mTransportType = TransportType::TcpUnknown;
+			else
-
-			} else {
 				mTransportType = TransportType::TcpUnknown;
-			}
+
 		} else {
-			mTransportType = TransportType::Unknown;
+			mTransportType = TransportType::TcpUnknown;
 		}
+	} else {
+		mTransportType = TransportType::Unknown;
+	}
+}
 
-		// Try to resolve the node
+void Candidate::hintMid(string mid) {
-		struct addrinfo hints = {};
+	if (!mMid)
-		hints.ai_family = AF_UNSPEC;
+		mMid.emplace(std::move(mid));
-		hints.ai_flags = AI_ADDRCONFIG;
+}
-		if (mTransportType == TransportType::Udp) {
-			hints.ai_socktype = SOCK_DGRAM;
-			hints.ai_protocol = IPPROTO_UDP;
-		} else if (mTransportType != TransportType::Unknown) {
-			hints.ai_socktype = SOCK_STREAM;
-			hints.ai_protocol = IPPROTO_TCP;
-		}
 
-		if (mode == ResolveMode::Simple)
+bool Candidate::resolve(ResolveMode mode) {
-			hints.ai_flags |= AI_NUMERICHOST;
+	PLOG_VERBOSE << "Resolving candidate (mode="
+	             << (mode == ResolveMode::Simple ? "simple" : "lookup") << "): " << mNode << ' '
+	             << mService;
 
-		struct addrinfo *result = nullptr;
+	// Try to resolve the node and service
-		if (getaddrinfo(node.c_str(), service.c_str(), &hints, &result) == 0) {
+	struct addrinfo hints = {};
-			for (auto p = result; p; p = p->ai_next) {
+	hints.ai_family = AF_UNSPEC;
-				if (p->ai_family == AF_INET || p->ai_family == AF_INET6) {
+	hints.ai_flags = AI_ADDRCONFIG;
-					// Rewrite the candidate
+	if (mTransportType == TransportType::Udp) {
-					char nodebuffer[MAX_NUMERICNODE_LEN];
+		hints.ai_socktype = SOCK_DGRAM;
-					char servbuffer[MAX_NUMERICSERV_LEN];
+		hints.ai_protocol = IPPROTO_UDP;
-					if (getnameinfo(p->ai_addr, socklen_t(p->ai_addrlen), nodebuffer,
+	} else if (mTransportType != TransportType::Unknown) {
-					                MAX_NUMERICNODE_LEN, servbuffer, MAX_NUMERICSERV_LEN,
+		hints.ai_socktype = SOCK_STREAM;
-					                NI_NUMERICHOST | NI_NUMERICSERV) == 0) {
+		hints.ai_protocol = IPPROTO_TCP;
+	}
 
-						mAddress = nodebuffer;
+	if (mode == ResolveMode::Simple)
-						mPort = uint16_t(std::stoul(servbuffer));
+		hints.ai_flags |= AI_NUMERICHOST;
-						mFamily = p->ai_family == AF_INET6 ? Family::Ipv6 : Family::Ipv4;
 
-						const char sp{' '};
+	struct addrinfo *result = nullptr;
-						std::ostringstream oss;
+	if (getaddrinfo(mNode.c_str(), mService.c_str(), &hints, &result) == 0) {
-						oss << foundation << sp << component << sp << transport << sp << priority;
+		for (auto p = result; p; p = p->ai_next) {
-						oss << sp << nodebuffer << sp << servbuffer << sp << "typ" << sp << type;
+			if (p->ai_family == AF_INET || p->ai_family == AF_INET6) {
-						oss << left;
+				char nodebuffer[MAX_NUMERICNODE_LEN];
-						mCandidate = oss.str();
+				char servbuffer[MAX_NUMERICSERV_LEN];
+				if (getnameinfo(p->ai_addr, socklen_t(p->ai_addrlen), nodebuffer,
+				                MAX_NUMERICNODE_LEN, servbuffer, MAX_NUMERICSERV_LEN,
+				                NI_NUMERICHOST | NI_NUMERICSERV) == 0) {
 
-						PLOG_VERBOSE << "Resolved candidate: " << mCandidate;
+					mAddress = nodebuffer;
-						break;
+					mPort = uint16_t(std::stoul(servbuffer));
-					}
+					mFamily = p->ai_family == AF_INET6 ? Family::Ipv6 : Family::Ipv4;
+					PLOG_VERBOSE << "Resolved candidate: " << mAddress << ' ' << mPort;
+					break;
 				}
 			}
-
-			freeaddrinfo(result);
 		}
+
+		freeaddrinfo(result);
 	}
 
 	return mFamily != Family::Unresolved;
 }
 
-string Candidate::candidate() const { return "candidate:" + mCandidate; }
+Candidate::Type Candidate::type() const { return mType; }
+
+Candidate::TransportType Candidate::transportType() const { return mTransportType; }
+
+uint32_t Candidate::priority() const { return mPriority; }
+
+string Candidate::candidate() const {
+	const char sp{' '};
+	std::ostringstream oss;
+	oss << "candidate:";
+	oss << mFoundation << sp << mComponent << sp << mTransportString << sp << mPriority << sp;
+	if (isResolved())
+		oss << mAddress << sp << mPort;
+	else
+		oss << mNode << sp << mService;
+
+	oss << sp << "typ" << sp << mTypeString;
+
+	if (!mTail.empty())
+		oss << sp << mTail;
+
+	return oss.str();
+}
 
 string Candidate::mid() const { return mMid.value_or("0"); }
 
@@ -186,14 +215,18 @@ Candidate::operator string() const {
 	return line.str();
 }
 
+bool Candidate::operator==(const Candidate &other) const {
+	return mFoundation == other.mFoundation;
+}
+
+bool Candidate::operator!=(const Candidate &other) const {
+	return mFoundation != other.mFoundation;
+}
+
 bool Candidate::isResolved() const { return mFamily != Family::Unresolved; }
 
 Candidate::Family Candidate::family() const { return mFamily; }
 
-Candidate::Type Candidate::type() const { return mType; }
-
-Candidate::TransportType Candidate::transportType() const { return mTransportType; }
-
 std::optional<string> Candidate::address() const {
 	return isResolved() ? std::make_optional(mAddress) : nullopt;
 }
@@ -202,10 +235,6 @@ std::optional<uint16_t> Candidate::port() const {
 	return isResolved() ? std::make_optional(mPort) : nullopt;
 }
 
-std::optional<uint32_t> Candidate::priority() const {
-	return isResolved() ? std::make_optional(mPriority) : nullopt;
-}
-
 } // namespace rtc
 
 std::ostream &operator<<(std::ostream &out, const rtc::Candidate &candidate) {
@@ -217,11 +246,11 @@ std::ostream &operator<<(std::ostream &out, const rtc::Candidate::Type &type) {
 	case rtc::Candidate::Type::Host:
 		return out << "host";
 	case rtc::Candidate::Type::PeerReflexive:
-		return out << "peer_reflexive";
+		return out << "prflx";
 	case rtc::Candidate::Type::ServerReflexive:
-		return out << "server_reflexive";
+		return out << "srflx";
 	case rtc::Candidate::Type::Relayed:
-		return out << "relayed";
+		return out << "relay";
 	default:
 		return out << "unknown";
 	}

src/datachannel.cpp

@@ -306,7 +306,7 @@ void NegociatedDataChannel::processOpenMessage(message_ptr message) {
 	mLabel.assign(end, open.labelLength);
 	mProtocol.assign(end + open.labelLength, open.protocolLength);
 
-	mReliability->unordered = (open.reliabilityParameter & 0x80) != 0;
+	mReliability->unordered = (open.channelType & 0x80) != 0;
 	switch (open.channelType & 0x7F) {
 	case CHANNEL_PARTIAL_RELIABLE_REXMIT:
 		mReliability->type = Reliability::Type::Rexmit;

src/description.cpp

@@ -29,13 +29,13 @@
 #include <unordered_map>
 
 using std::shared_ptr;
-using std::size_t;
-using std::string;
-using std::string_view;
 using std::chrono::system_clock;
 
 namespace {
 
+using std::string;
+using std::string_view;
+
 inline bool match_prefix(string_view str, string_view prefix) {
 	return str.size() >= prefix.size() &&
 	       std::mismatch(prefix.begin(), prefix.end(), str.begin()).first == prefix.end();
@@ -106,7 +106,7 @@ Description::Description(const string &sdp, Type type, Role role)
 					               mFingerprint->begin(),
 					               [](char c) { return char(std::toupper(c)); });
 				} else {
-					PLOG_WARNING << "Unknown SDP fingerprint type: " << value;
+					PLOG_WARNING << "Unknown SDP fingerprint format: " << value;
 				}
 			} else if (key == "ice-ufrag") {
 				mIceUfrag = value;
@@ -171,16 +171,27 @@ void Description::setFingerprint(string fingerprint) {
 	mFingerprint.emplace(std::move(fingerprint));
 }
 
+bool Description::hasCandidate(const Candidate &candidate) const {
+	for (const Candidate &other : mCandidates)
+		if (candidate == other)
+			return true;
+
+	return false;
+}
+
 void Description::addCandidate(Candidate candidate) {
 	candidate.hintMid(bundleMid());
+
+	for (const Candidate &other : mCandidates)
+		if (candidate == other)
+			return;
+
 	mCandidates.emplace_back(std::move(candidate));
 }
 
 void Description::addCandidates(std::vector<Candidate> candidates) {
-	for (Candidate candidate : candidates) {
+	for (Candidate candidate : candidates)
-		candidate.hintMid(bundleMid());
+		addCandidate(std::move(candidate));
-		mCandidates.emplace_back(std::move(candidate));
-	}
 }
 
 void Description::endCandidates() { mEnded = true; }
@@ -472,8 +483,7 @@ string Description::Entry::generateSdpLines(string_view eol) const {
 	}
 
 	for (const auto &attr : mAttributes) {
-		if (attr.find("extmap") == std::string::npos &&
+		if (attr.find("extmap") == string::npos && attr.find("rtcp-rsize") == string::npos)
-		    attr.find("rtcp-rsize") == std::string::npos)
 			sdp << "a=" << attr << eol;
 	}
 
@@ -508,12 +518,21 @@ Description::Entry::removeAttribute(std::vector<string>::iterator it) {
 	return mAttributes.erase(it);
 }
 
-void Description::Media::addSSRC(uint32_t ssrc, std::string name) {
+void Description::Media::addSSRC(uint32_t ssrc, std::optional<string> name,
-	mAttributes.emplace_back("ssrc:" + std::to_string(ssrc) + " cname:" + name);
+                                 std::optional<string> msid) {
+	if (name)
+		mAttributes.emplace_back("ssrc:" + std::to_string(ssrc) + " cname:" + *name);
+	else
+		mAttributes.emplace_back("ssrc:" + std::to_string(ssrc));
+
+	if (msid)
+		mAttributes.emplace_back("ssrc:" + std::to_string(ssrc) + " msid:" + *msid + " " + *msid);
+
 	mSsrcs.emplace_back(ssrc);
 }
 
-void Description::Media::replaceSSRC(uint32_t oldSSRC, uint32_t ssrc, std::string name) {
+void Description::Media::replaceSSRC(uint32_t oldSSRC, uint32_t ssrc, std::optional<string> name,
+                                     std::optional<string> msid) {
 	auto it = mAttributes.begin();
 	while (it != mAttributes.end()) {
 		if (it->find("ssrc:" + std::to_string(oldSSRC)) == 0) {
@@ -521,11 +540,17 @@ void Description::Media::replaceSSRC(uint32_t oldSSRC, uint32_t ssrc, std::strin
 		} else
 			it++;
 	}
-	mAttributes.emplace_back("ssrc:" + std::to_string(ssrc) + " cname:" + name);
+	addSSRC(ssrc, std::move(name), std::move(msid));
 }
 
-void Description::Media::addSSRC(uint32_t ssrc) {
+void Description::Media::removeSSRC(uint32_t oldSSRC) {
-	mAttributes.emplace_back("ssrc:" + std::to_string(ssrc));
+	auto it = mAttributes.begin();
+	while (it != mAttributes.end()) {
+		if (it->find("ssrc:" + std::to_string(oldSSRC)) == 0) {
+			it = mAttributes.erase(it);
+		} else
+			it++;
+	}
 }
 
 bool Description::Media::hasSSRC(uint32_t ssrc) {
@@ -678,32 +703,17 @@ void Description::Media::removeFormat(const string &fmt) {
 	}
 }
 
-void Description::Video::addVideoCodec(int payloadType, const string &codec) {
+void Description::Video::addVideoCodec(int payloadType, string codec,
+                                       std::optional<string> profile) {
 	RTPMap map(std::to_string(payloadType) + ' ' + codec + "/90000");
 	map.addFB("nack");
 	map.addFB("nack pli");
-	//    map.addFB("nack fir");
+	//    map.addFB("ccm fir");
 	map.addFB("goog-remb");
-	if (codec == "H264") {
+	if (profile)
-		// Use Constrained Baseline profile Level 4.2 (necessary for Firefox)
+		map.fmtps.emplace_back(*profile);
-		// https://developer.mozilla.org/en-US/docs/Web/Media/Formats/WebRTC_codecs#Supported_video_codecs
-		// TODO: Should be 42E0 but 42C0 appears to be more compatible. Investigate this.
-		map.fmtps.emplace_back(
-		    "profile-level-id=4de01f;packetization-mode=1;level-asymmetry-allowed=1");
-
-		// Because certain Android devices don't like me, let us just negotiate some random
-		{
-			RTPMap map(std::to_string(payloadType + 1) + ' ' + codec + "/90000");
-			map.addFB("nack");
-			map.addFB("nack pli");
-			//            map.addFB("nack fir");
-			map.addFB("goog-remb");
-			addRTPMap(map);
-		}
-	}
 	addRTPMap(map);
 
-	//	// RTX Packets
 	/* TODO
 	 *  TIL that Firefox does not properly support the negotiation of RTX! It works, but doesn't
 	 * negotiate the SSRC so we have no idea what SSRC is RTX going to be. Three solutions: One) we
@@ -711,24 +721,34 @@ void Description::Video::addVideoCodec(int payloadType, const string &codec) {
 	 * rebuild the original packet before we send it distribute it to each track. Three) we complain
 	 * to mozilla. This one probably won't do much.
 	 */
-	//    RTPMap rtx(std::to_string(payloadType+1) + " rtx/90000");
+	// RTX Packets
-	//    // TODO rtx-time is how long can a request be stashed for before needing to resend it.
+	// RTPMap rtx(std::to_string(payloadType+1) + " rtx/90000");
-	//    Needs to be parameterized rtx.addAttribute("apt=" + std::to_string(payloadType) +
+	// // TODO rtx-time is how long can a request be stashed for before needing to resend it.
-	//    ";rtx-time=3000"); addRTPMap(rtx);
+	// Needs to be parameterized rtx.addAttribute("apt=" + std::to_string(payloadType) +
+	// ";rtx-time=3000"); addRTPMap(rtx);
 }
 
-void Description::Audio::addAudioCodec(int payloadType, const string &codec) {
+void Description::Audio::addAudioCodec(int payloadType, string codec,
+                                       std::optional<string> profile) {
 	// TODO This 48000/2 should be parameterized
 	RTPMap map(std::to_string(payloadType) + ' ' + codec + "/48000/2");
-	map.fmtps.emplace_back("maxaveragebitrate=96000; stereo=1; sprop-stereo=1; useinbandfec=1");
+	if (profile)
+		map.fmtps.emplace_back(*profile);
+	addRTPMap(map);
+}
+
+void Description::Media::addRTXCodec(unsigned int payloadType, unsigned int originalPayloadType,
+                                     unsigned int clockRate) {
+	RTPMap map(std::to_string(payloadType) + " RTX/" + std::to_string(clockRate));
+	map.fmtps.emplace_back("apt=" + std::to_string(originalPayloadType));
 	addRTPMap(map);
 }
 
 void Description::Video::addH264Codec(int pt) { addVideoCodec(pt, "H264"); }
 
-void Description::Video::addVP8Codec(int payloadType) { addVideoCodec(payloadType, "VP8"); }
+void Description::Video::addVP8Codec(int payloadType) { addVideoCodec(payloadType, "VP8", nullopt); }
 
-void Description::Video::addVP9Codec(int payloadType) { addVideoCodec(payloadType, "VP9"); }
+void Description::Video::addVP9Codec(int payloadType) { addVideoCodec(payloadType, "VP9", nullopt); }
 
 void Description::Media::setBitrate(int bitrate) { mBas = bitrate; }
 
@@ -797,7 +817,7 @@ void Description::Media::parseSdpLine(string_view line) {
 		} else if (key == "rtcp-mux") {
 			// always added
 		} else if (key == "ssrc") {
-			mSsrcs.emplace_back(std::stoul((std::string)value));
+			mSsrcs.emplace_back(std::stoul(string(value)));
 		} else {
 			Entry::parseSdpLine(line);
 		}
@@ -817,7 +837,7 @@ std::vector<uint32_t> Description::Media::getSSRCs() {
 	for (auto &val : mAttributes) {
 		PLOG_DEBUG << val;
 		if (val.find("ssrc:") == 0) {
-			vec.emplace_back(std::stoul((std::string)val.substr(5, val.find(" "))));
+			vec.emplace_back(std::stoul(string(val.substr(5, val.find(" ")))));
 		}
 	}
 	return vec;
@@ -841,7 +861,7 @@ Description::Media::RTPMap::RTPMap(string_view mline) { setMLine(mline); }
 void Description::Media::RTPMap::removeFB(const string &str) {
 	auto it = rtcpFbs.begin();
 	while (it != rtcpFbs.end()) {
-		if (it->find(str) != std::string::npos) {
+		if (it->find(str) != string::npos) {
 			it = rtcpFbs.erase(it);
 		} else
 			it++;

src/dtlssrtptransport.cpp

@@ -110,7 +110,7 @@ bool DtlsSrtpTransport::sendMedia(message_ptr message) {
 			if (err == srtp_err_status_replay_fail)
 				throw std::runtime_error("SRTCP packet is a replay");
 			else if (err == srtp_err_status_no_ctx) {
-				auto ssrc = ((RTCP_SR *)message->data())->senderSSRC();
+				auto ssrc = reinterpret_cast<RTCP_SR *>(message->data())->senderSSRC();
 				PLOG_INFO << "Adding SSRC to SRTCP: " << ssrc;
 				addSSRC(ssrc);
 				if ((err = srtp_protect_rtcp(mSrtpOut, message->data(), &size)))
@@ -127,11 +127,11 @@ bool DtlsSrtpTransport::sendMedia(message_ptr message) {
 			if (err == srtp_err_status_replay_fail)
 				throw std::runtime_error("Outgoing SRTP packet is a replay");
 			else if (err == srtp_err_status_no_ctx) {
-				auto ssrc = ((RTP *)message->data())->ssrc();
+				auto ssrc = reinterpret_cast<RTP *>(message->data())->ssrc();
 				PLOG_INFO << "Adding SSRC to RTP: " << ssrc;
 				addSSRC(ssrc);
-				if ((err = srtp_protect_rtcp(mSrtpOut, message->data(), &size)))
+				if ((err = srtp_protect(mSrtpOut, message->data(), &size)))
-					throw std::runtime_error("SRTCP protect error, status=" +
+					throw std::runtime_error("SRTP protect error, status=" +
 					                         to_string(static_cast<int>(err)));
 			} else
 				throw std::runtime_error("SRTP protect error, status=" +
@@ -141,7 +141,14 @@ bool DtlsSrtpTransport::sendMedia(message_ptr message) {
 	}
 
 	message->resize(size);
-	return outgoing(message);
+
+	if (message->dscp == 0) { // Track might override the value
+		// Set recommended medium-priority DSCP value
+		// See https://tools.ietf.org/html/draft-ietf-tsvwg-rtcweb-qos-18
+		message->dscp = 36; // AF42: Assured Forwarding class 4, medium drop probability
+	}
+
+	return Transport::outgoing(message); // bypass DTLS DSCP marking
 }
 
 void DtlsSrtpTransport::incoming(message_ptr message) {
@@ -189,7 +196,7 @@ void DtlsSrtpTransport::incoming(message_ptr message) {
 				else if (err == srtp_err_status_auth_fail)
 					PLOG_WARNING << "Incoming SRTCP packet failed authentication check";
 				else if (err == srtp_err_status_no_ctx) {
-					auto ssrc = ((RTCP_SR *)message->data())->senderSSRC();
+					auto ssrc = reinterpret_cast<RTCP_SR *>(message->data())->senderSSRC();
 					PLOG_INFO << "Adding SSRC to RTCP: " << ssrc;
 					addSSRC(ssrc);
 					if ((err = srtp_unprotect_rtcp(mSrtpIn, message->data(), &size)))
@@ -203,8 +210,7 @@ void DtlsSrtpTransport::incoming(message_ptr message) {
 			}
 			PLOG_VERBOSE << "Unprotected SRTCP packet, size=" << size;
 			message->type = Message::Type::Control;
-			auto rtp = (RTCP_SR *)message->data();
+			message->stream = reinterpret_cast<RTCP_SR *>(message->data())->senderSSRC();
-			message->stream = rtp->senderSSRC();
 		} else {
 			PLOG_VERBOSE << "Incoming SRTP packet, size=" << size;
 			if (srtp_err_status_t err = srtp_unprotect(mSrtpIn, message->data(), &size)) {
@@ -213,21 +219,20 @@ void DtlsSrtpTransport::incoming(message_ptr message) {
 				else if (err == srtp_err_status_auth_fail)
 					PLOG_WARNING << "Incoming SRTP packet failed authentication check";
 				else if (err == srtp_err_status_no_ctx) {
-					auto ssrc = ((RTP *)message->data())->ssrc();
+					auto ssrc = reinterpret_cast<RTP *>(message->data())->ssrc();
 					PLOG_INFO << "Adding SSRC to RTP: " << ssrc;
 					addSSRC(ssrc);
 					if ((err = srtp_unprotect(mSrtpIn, message->data(), &size)))
-						throw std::runtime_error("SRTCP unprotect error, status=" +
+						throw std::runtime_error("SRTP unprotect error, status=" +
 						                         to_string(static_cast<int>(err)));
 				} else
 					PLOG_WARNING << "SRTP unprotect error, status=" << err
-					             << " SSRC=" << ((RTP *)message->data())->ssrc();
+					             << " SSRC=" << reinterpret_cast<RTP *>(message->data())->ssrc();
 				return;
 			}
 			PLOG_VERBOSE << "Unprotected SRTP packet, size=" << size;
 			message->type = Message::Type::Binary;
-			auto rtp = (RTP *)message->data();
+			message->stream = reinterpret_cast<RTP *>(message->data())->ssrc();
-			message->stream = rtp->ssrc();
 		}
 
 		message->resize(size);

src/dtlstransport.cpp

@@ -53,7 +53,7 @@ DtlsTransport::DtlsTransport(shared_ptr<IceTransport> lower, certificate_ptr cer
                              verifier_callback verifierCallback, state_callback stateChangeCallback)
     : Transport(lower, std::move(stateChangeCallback)), mCertificate(certificate),
       mVerifierCallback(std::move(verifierCallback)),
-      mIsClient(lower->role() == Description::Role::Active) {
+      mIsClient(lower->role() == Description::Role::Active), mCurrentDscp(0) {
 
 	PLOG_DEBUG << "Initializing DTLS transport (GnuTLS)";
 
@@ -122,6 +122,7 @@ bool DtlsTransport::send(message_ptr message) {
 
 	PLOG_VERBOSE << "Send size=" << message->size();
 
+	mCurrentDscp = message->dscp;
 	ssize_t ret;
 	do {
 		ret = gnutls_record_send(mSession, message->data(), message->size());
@@ -143,6 +144,13 @@ void DtlsTransport::incoming(message_ptr message) {
 	mIncomingQueue.push(message);
 }
 
+bool DtlsTransport::outgoing(message_ptr message) {
+	if (message->dscp == 0)
+		message->dscp = mCurrentDscp;
+
+	return Transport::outgoing(std::move(message));
+}
+
 void DtlsTransport::postHandshake() {
 	// Dummy
 }
@@ -309,7 +317,7 @@ DtlsTransport::DtlsTransport(shared_ptr<IceTransport> lower, shared_ptr<Certific
                              verifier_callback verifierCallback, state_callback stateChangeCallback)
     : Transport(lower, std::move(stateChangeCallback)), mCertificate(certificate),
       mVerifierCallback(std::move(verifierCallback)),
-      mIsClient(lower->role() == Description::Role::Active) {
+      mIsClient(lower->role() == Description::Role::Active), mCurrentDscp(0) {
 	PLOG_DEBUG << "Initializing DTLS transport (OpenSSL)";
 
 	try {
@@ -405,6 +413,7 @@ bool DtlsTransport::send(message_ptr message) {
 
 	PLOG_VERBOSE << "Send size=" << message->size();
 
+	mCurrentDscp = message->dscp;
 	int ret = SSL_write(mSsl, message->data(), int(message->size()));
 	return openssl::check(mSsl, ret);
 }
@@ -419,6 +428,13 @@ void DtlsTransport::incoming(message_ptr message) {
 	mIncomingQueue.push(message);
 }
 
+bool DtlsTransport::outgoing(message_ptr message) {
+	if (message->dscp == 0)
+		message->dscp = mCurrentDscp;
+
+	return Transport::outgoing(std::move(message));
+}
+
 void DtlsTransport::postHandshake() {
 	// Dummy
 }

src/dtlstransport.hpp

@@ -53,6 +53,7 @@ public:
 
 protected:
 	virtual void incoming(message_ptr message) override;
+	virtual bool outgoing(message_ptr message) override;
 	virtual void postHandshake();
 	void runRecvLoop();
 
@@ -62,6 +63,7 @@ protected:
 
 	Queue<message_ptr> mIncomingQueue;
 	std::thread mRecvThread;
+	std::atomic<unsigned int> mCurrentDscp;
 
 #if USE_GNUTLS
 	gnutls_session_t mSession;

src/icetransport.cpp

@@ -46,11 +46,12 @@ using std::chrono::system_clock;
 
 namespace rtc {
 
-IceTransport::IceTransport(const Configuration &config, Description::Role role,
+IceTransport::IceTransport(const Configuration &config, candidate_callback candidateCallback,
-                           candidate_callback candidateCallback, state_callback stateChangeCallback,
+                           state_callback stateChangeCallback,
                            gathering_state_callback gatheringStateChangeCallback)
-    : Transport(nullptr, std::move(stateChangeCallback)), mRole(role), mMid("0"),
+    : Transport(nullptr, std::move(stateChangeCallback)), mRole(Description::Role::ActPass),
-      mGatheringState(GatheringState::New), mCandidateCallback(std::move(candidateCallback)),
+      mMid("0"), mGatheringState(GatheringState::New),
+      mCandidateCallback(std::move(candidateCallback)),
       mGatheringStateChangeCallback(std::move(gatheringStateChangeCallback)),
       mAgent(nullptr, nullptr) {
 
@@ -139,13 +140,19 @@ Description IceTransport::getLocalDescription(Description::Type type) const {
 	if (juice_get_local_description(mAgent.get(), sdp, JUICE_MAX_SDP_STRING_LEN) < 0)
 		throw std::runtime_error("Failed to generate local SDP");
 
+	// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
+	// setup:actpass.
+	// See https://tools.ietf.org/html/rfc5763#section-5
 	return Description(string(sdp), type,
 	                   type == Description::Type::Offer ? Description::Role::ActPass : mRole);
 }
 
 void IceTransport::setRemoteDescription(const Description &description) {
-	mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+	if (mRole == Description::Role::ActPass)
-	                                                        : Description::Role::Active;
+		mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+		                                                        : Description::Role::Active;
+	if (mRole == description.role())
+		throw std::logic_error("Incompatible roles with remote description");
 
 	mMid = description.bundleMid();
 	if (juice_set_remote_description(mAgent.get(),
@@ -161,7 +168,9 @@ bool IceTransport::addRemoteCandidate(const Candidate &candidate) {
 	return juice_add_remote_candidate(mAgent.get(), string(candidate).c_str()) >= 0;
 }
 
-void IceTransport::gatherLocalCandidates() {
+void IceTransport::gatherLocalCandidates(string mid) {
+	mMid = std::move(mid);
+
 	// Change state now as candidates calls can be synchronous
 	changeGatheringState(GatheringState::InProgress);
 
@@ -215,8 +224,10 @@ bool IceTransport::send(message_ptr message) {
 }
 
 bool IceTransport::outgoing(message_ptr message) {
-	return juice_send(mAgent.get(), reinterpret_cast<const char *>(message->data()),
+	// Explicit Congestion Notification takes the least-significant 2 bits of the DS field
-	                  message->size()) >= 0;
+	int ds = int(message->dscp << 2);
+	return juice_send_diffserv(mAgent.get(), reinterpret_cast<const char *>(message->data()),
+	                           message->size(), ds) >= 0;
 }
 
 void IceTransport::changeGatheringState(GatheringState state) {
@@ -316,13 +327,14 @@ void IceTransport::LogCallback(juice_log_level_t level, const char *message) {
 
 namespace rtc {
 
-IceTransport::IceTransport(const Configuration &config, Description::Role role,
+IceTransport::IceTransport(const Configuration &config, candidate_callback candidateCallback,
-                           candidate_callback candidateCallback, state_callback stateChangeCallback,
+                           state_callback stateChangeCallback,
                            gathering_state_callback gatheringStateChangeCallback)
-    : Transport(nullptr, std::move(stateChangeCallback)), mRole(role), mMid("0"),
+    : Transport(nullptr, std::move(stateChangeCallback)), mRole(Description::Role::ActPass),
-      mGatheringState(GatheringState::New), mCandidateCallback(std::move(candidateCallback)),
+      mMid("0"), mGatheringState(GatheringState::New),
+      mCandidateCallback(std::move(candidateCallback)),
       mGatheringStateChangeCallback(std::move(gatheringStateChangeCallback)),
-      mNiceAgent(nullptr, nullptr), mMainLoop(nullptr, nullptr) {
+      mNiceAgent(nullptr, nullptr), mMainLoop(nullptr, nullptr), mOutgoingDscp(0) {
 
 	PLOG_DEBUG << "Initializing ICE transport (libnice)";
 
@@ -526,12 +538,21 @@ Description IceTransport::getLocalDescription(Description::Type type) const {
 
 	std::unique_ptr<gchar[], void (*)(void *)> sdp(nice_agent_generate_local_sdp(mNiceAgent.get()),
 	                                               g_free);
-	return Description(string(sdp.get()), type, mRole);
+
+	// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
+	// setup:actpass.
+	// See https://tools.ietf.org/html/rfc5763#section-5
+	return Description(string(sdp.get()), type,
+	                   type == Description::Type::Offer ? Description::Role::ActPass : mRole);
 }
 
 void IceTransport::setRemoteDescription(const Description &description) {
-	mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+	if (mRole == Description::Role::ActPass)
-	                                                        : Description::Role::Active;
+		mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+		                                                        : Description::Role::Active;
+	if (mRole == description.role())
+		throw std::logic_error("Incompatible roles with remote description");
+
 	mMid = description.bundleMid();
 	mTrickleTimeout = !description.ended() ? 30s : 0s;
 
@@ -547,12 +568,14 @@ bool IceTransport::addRemoteCandidate(const Candidate &candidate) {
 		return false;
 
 	// Warning: the candidate string must start with "a=candidate:" and it must not end with a
-	// newline, else libnice will reject it.
+	// newline or whitespace, else libnice will reject it.
 	string sdp(candidate);
 	NiceCandidate *cand =
 	    nice_agent_parse_remote_candidate_sdp(mNiceAgent.get(), mStreamId, sdp.c_str());
-	if (!cand)
+	if (!cand) {
+		PLOG_WARNING << "Rejected ICE candidate: " << sdp;
 		return false;
+	}
 
 	GSList *list = g_slist_append(nullptr, cand);
 	int ret = nice_agent_set_remote_candidates(mNiceAgent.get(), mStreamId, 1, list);
@@ -561,7 +584,9 @@ bool IceTransport::addRemoteCandidate(const Candidate &candidate) {
 	return ret > 0;
 }
 
-void IceTransport::gatherLocalCandidates() {
+void IceTransport::gatherLocalCandidates(string mid) {
+	mMid = std::move(mid);
+
 	// Change state now as candidates calls can be synchronous
 	changeGatheringState(GatheringState::InProgress);
 
@@ -598,6 +623,13 @@ bool IceTransport::send(message_ptr message) {
 }
 
 bool IceTransport::outgoing(message_ptr message) {
+	std::lock_guard lock(mOutgoingMutex);
+	if (mOutgoingDscp != message->dscp) {
+		mOutgoingDscp = message->dscp;
+		// Explicit Congestion Notification takes the least-significant 2 bits of the DS field
+		int ds = int(message->dscp << 2);
+		nice_agent_set_stream_tos(mNiceAgent.get(), mStreamId, ds); // ToS is the legacy name for DS
+	}
 	return nice_agent_send(mNiceAgent.get(), mStreamId, 1, message->size(),
 	                       reinterpret_cast<const char *>(message->data())) >= 0;
 }

src/icetransport.hpp

@@ -35,6 +35,7 @@
 #include <atomic>
 #include <chrono>
 #include <thread>
+#include <mutex>
 
 namespace rtc {
 
@@ -45,8 +46,8 @@ public:
 	using candidate_callback = std::function<void(const Candidate &candidate)>;
 	using gathering_state_callback = std::function<void(GatheringState state)>;
 
-	IceTransport(const Configuration &config, Description::Role role,
+	IceTransport(const Configuration &config, candidate_callback candidateCallback,
-	             candidate_callback candidateCallback, state_callback stateChangeCallback,
+	             state_callback stateChangeCallback,
 	             gathering_state_callback gatheringStateChangeCallback);
 	~IceTransport();
 
@@ -55,7 +56,7 @@ public:
 	Description getLocalDescription(Description::Type type) const;
 	void setRemoteDescription(const Description &description);
 	bool addRemoteCandidate(const Candidate &candidate);
-	void gatherLocalCandidates();
+	void gatherLocalCandidates(string mid);
 
 	std::optional<string> getLocalAddress() const;
 	std::optional<string> getRemoteAddress() const;
@@ -99,6 +100,8 @@ private:
 	std::unique_ptr<GMainLoop, void (*)(GMainLoop *)> mMainLoop;
 	std::thread mMainLoopThread;
 	guint mTimeoutId = 0;
+	std::mutex mOutgoingMutex;
+	unsigned int mOutgoingDscp;
 
 	static string AddressToString(const NiceAddress &addr);
 

src/peerconnection.cpp

@@ -77,7 +77,7 @@ void PeerConnection::close() {
 	mNegotiationNeeded = false;
 
 	// Close data channels asynchronously
-	mProcessor->enqueue(std::bind(&PeerConnection::closeDataChannels, this));
+	mProcessor->enqueue(&PeerConnection::closeDataChannels, this);
 
 	closeTransports();
 }
@@ -187,21 +187,16 @@ void PeerConnection::setLocalDescription(Description::Type type) {
 	}
 	}
 
-	auto iceTransport = std::atomic_load(&mIceTransport);
+	auto iceTransport = initIceTransport();
-	if (!iceTransport) {
-		// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
-		// setup:actpass.
-		// See https://tools.ietf.org/html/rfc5763#section-5
-		iceTransport = initIceTransport(Description::Role::ActPass);
-	}
 
-	Description localDescription = iceTransport->getLocalDescription(type);
+	Description local = iceTransport->getLocalDescription(type);
-	processLocalDescription(std::move(localDescription));
+	processLocalDescription(std::move(local));
 
 	changeSignalingState(newSignalingState);
 
-	if (mGatheringState == GatheringState::New)
+	if (mGatheringState == GatheringState::New) {
-		iceTransport->gatherLocalCandidates();
+		iceTransport->gatherLocalCandidates(localBundleMid());
+	}
 }
 
 void PeerConnection::setRemoteDescription(Description description) {
@@ -272,12 +267,6 @@ void PeerConnection::setRemoteDescription(Description description) {
 	// Candidates will be added at the end, extract them for now
 	auto remoteCandidates = description.extractCandidates();
 	auto type = description.type();
-
-	auto iceTransport = std::atomic_load(&mIceTransport);
-	if (!iceTransport)
-		iceTransport = initIceTransport(Description::Role::ActPass);
-
-	iceTransport->setRemoteDescription(description);
 	processRemoteDescription(std::move(description));
 
 	changeSignalingState(newSignalingState);
@@ -287,8 +276,9 @@ void PeerConnection::setRemoteDescription(Description description) {
 		setLocalDescription(Description::Type::Answer);
 	} else {
 		// This is an answer
+		auto iceTransport = std::atomic_load(&mIceTransport);
 		auto sctpTransport = std::atomic_load(&mSctpTransport);
-		if (!sctpTransport && iceTransport->role() == Description::Role::Active) {
+		if (!sctpTransport && iceTransport && iceTransport->role() == Description::Role::Active) {
 			// Since we assumed passive role during DataChannel creation, we need to shift the
 			// stream numbers by one to shift them from odd to even.
 			std::unique_lock lock(mDataChannelsMutex); // we are going to swap the container
@@ -380,7 +370,7 @@ void PeerConnection::onSignalingStateChange(std::function<void(SignalingState st
 std::shared_ptr<Track> PeerConnection::addTrack(Description::Media description) {
 #if !RTC_ENABLE_MEDIA
 	if (mTracks.empty()) {
-		PLOG_WARNING << "Tracks will be inative (not compiled with SRTP support)";
+		PLOG_WARNING << "Tracks will be inative (not compiled with media support)";
 	}
 #endif
 
@@ -405,14 +395,14 @@ void PeerConnection::onTrack(std::function<void(std::shared_ptr<Track>)> callbac
 	mTrackCallback = callback;
 }
 
-shared_ptr<IceTransport> PeerConnection::initIceTransport(Description::Role role) {
+shared_ptr<IceTransport> PeerConnection::initIceTransport() {
 	PLOG_VERBOSE << "Starting ICE transport";
 	try {
 		if (auto transport = std::atomic_load(&mIceTransport))
 			return transport;
 
 		auto transport = std::make_shared<IceTransport>(
-		    mConfig, role, weak_bind(&PeerConnection::processLocalCandidate, this, _1),
+		    mConfig, weak_bind(&PeerConnection::processLocalCandidate, this, _1),
 		    [this, weak_this = weak_from_this()](IceTransport::State state) {
 			    auto shared_this = weak_this.lock();
 			    if (!shared_this)
@@ -490,7 +480,7 @@ shared_ptr<DtlsTransport> PeerConnection::initDtlsTransport() {
 				else
 					changeState(State::Connected);
 
-				mProcessor->enqueue(std::bind(&PeerConnection::openTracks, this));
+				mProcessor->enqueue(&PeerConnection::openTracks, this);
 				break;
 			case DtlsTransport::State::Failed:
 				changeState(State::Failed);
@@ -514,7 +504,7 @@ shared_ptr<DtlsTransport> PeerConnection::initDtlsTransport() {
 			    lower, certificate, verifierCallback,
 			    std::bind(&PeerConnection::forwardMedia, this, _1), stateChangeCallback);
 #else
-			PLOG_WARNING << "Ignoring media support (not compiled with SRTP support)";
+			PLOG_WARNING << "Ignoring media support (not compiled with media support)";
 #endif
 		}
 
@@ -561,16 +551,16 @@ shared_ptr<SctpTransport> PeerConnection::initSctpTransport() {
 			    switch (state) {
 			    case SctpTransport::State::Connected:
 				    changeState(State::Connected);
-				    mProcessor->enqueue(std::bind(&PeerConnection::openDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::openDataChannels, this);
 				    break;
 			    case SctpTransport::State::Failed:
 				    LOG_WARNING << "SCTP transport failed";
 				    changeState(State::Failed);
-				    mProcessor->enqueue(std::bind(&PeerConnection::remoteCloseDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::remoteCloseDataChannels, this);
 				    break;
 			    case SctpTransport::State::Disconnected:
 				    changeState(State::Disconnected);
-				    mProcessor->enqueue(std::bind(&PeerConnection::remoteCloseDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::remoteCloseDataChannels, this);
 				    break;
 			    default:
 				    // Ignore
@@ -659,10 +649,10 @@ void PeerConnection::forwardMessage(message_ptr message) {
 		    stream % 2 == remoteParity) {
 
 			channel = std::make_shared<NegociatedDataChannel>(shared_from_this(), sctpTransport,
-			                                                  message->stream);
+			                                                  stream);
 			channel->onOpen(weak_bind(&PeerConnection::triggerDataChannel, this,
 			                          weak_ptr<DataChannel>{channel}));
-			mDataChannels.emplace(message->stream, channel);
+			mDataChannels.emplace(stream, channel);
 		} else {
 			// Invalid, close the DataChannel
 			sctpTransport->closeStream(message->stream);
@@ -883,7 +873,7 @@ void PeerConnection::incomingTrack(Description::Media description) {
 	std::unique_lock lock(mTracksMutex); // we are going to emplace
 #if !RTC_ENABLE_MEDIA
 	if (mTracks.empty()) {
-		PLOG_WARNING << "Tracks will be inative (not compiled with SRTP support)";
+		PLOG_WARNING << "Tracks will be inative (not compiled with media support)";
 	}
 #endif
 	if (mTracks.find(description.mid()) == mTracks.end()) {
@@ -1024,7 +1014,10 @@ void PeerConnection::processLocalDescription(Description description) {
 		if (!description.hasApplication()) {
 			std::shared_lock lock(mDataChannelsMutex);
 			if (!mDataChannels.empty()) {
-				Description::Application app("data");
+				unsigned int m = 0;
+				while (description.hasMid(std::to_string(m)))
+					++m;
+				Description::Application app(std::to_string(m));
 				app.setSctpPort(DEFAULT_SCTP_PORT);
 				app.setMaxMessageSize(LOCAL_MAX_MESSAGE_SIZE);
 
@@ -1069,19 +1062,17 @@ void PeerConnection::processLocalDescription(Description description) {
 			mCurrentLocalDescription.emplace(std::move(*mLocalDescription));
 		}
 
-		mLocalDescription.emplace(std::move(description));
+		mLocalDescription.emplace(description);
 		mLocalDescription->addCandidates(std::move(existingCandidates));
 	}
 
-	mProcessor->enqueue([this, description = *mLocalDescription]() {
+	PLOG_VERBOSE << "Issuing local description: " << description;
-		PLOG_VERBOSE << "Issuing local description: " << description;
+	mProcessor->enqueue(mLocalDescriptionCallback.wrap(), std::move(description));
-		mLocalDescriptionCallback(std::move(description));
-	});
 
 	// Reciprocated tracks might need to be open
 	if (auto dtlsTransport = std::atomic_load(&mDtlsTransport);
 	    dtlsTransport && dtlsTransport->state() == Transport::State::Connected)
-		mProcessor->enqueue(std::bind(&PeerConnection::openTracks, this));
+		mProcessor->enqueue(&PeerConnection::openTracks, this);
 }
 
 void PeerConnection::processLocalCandidate(Candidate candidate) {
@@ -1089,13 +1080,11 @@ void PeerConnection::processLocalCandidate(Candidate candidate) {
 	if (!mLocalDescription)
 		throw std::logic_error("Got a local candidate without local description");
 
-	candidate.resolve(Candidate::ResolveMode::Simple); // for proper SDP generation later
+	candidate.resolve(Candidate::ResolveMode::Simple);
 	mLocalDescription->addCandidate(candidate);
 
-	mProcessor->enqueue([this, candidate = std::move(candidate)]() {
+	PLOG_VERBOSE << "Issuing local candidate: " << candidate;
-		PLOG_VERBOSE << "Issuing local candidate: " << candidate;
+	mProcessor->enqueue(mLocalCandidateCallback.wrap(), std::move(candidate));
-		mLocalCandidateCallback(std::move(candidate));
-	});
 }
 
 void PeerConnection::processRemoteDescription(Description description) {
@@ -1107,10 +1096,13 @@ void PeerConnection::processRemoteDescription(Description description) {
 		if (mRemoteDescription)
 			existingCandidates = mRemoteDescription->extractCandidates();
 
-		mRemoteDescription.emplace(std::move(description));
+		mRemoteDescription.emplace(description);
 		mRemoteDescription->addCandidates(std::move(existingCandidates));
 	}
 
+	auto iceTransport = initIceTransport();
+	iceTransport->setRemoteDescription(std::move(description));
+
 	if (description.hasApplication()) {
 		auto dtlsTransport = std::atomic_load(&mDtlsTransport);
 		auto sctpTransport = std::atomic_load(&mSctpTransport);
@@ -1121,28 +1113,45 @@ void PeerConnection::processRemoteDescription(Description description) {
 }
 
 void PeerConnection::processRemoteCandidate(Candidate candidate) {
-	std::lock_guard lock(mRemoteDescriptionMutex);
 	auto iceTransport = std::atomic_load(&mIceTransport);
-	if (!mRemoteDescription || !iceTransport)
+	{
-		throw std::logic_error("Got a remote candidate without remote description");
+		// Set as remote candidate
+		std::lock_guard lock(mRemoteDescriptionMutex);
+		if (!mRemoteDescription)
+			throw std::logic_error("Got a remote candidate without remote description");
 
-	candidate.hintMid(mRemoteDescription->bundleMid());
+		if (!iceTransport)
+			throw std::logic_error("Got a remote candidate without ICE transport");
 
-	if (candidate.resolve(Candidate::ResolveMode::Simple)) {
+		candidate.hintMid(mRemoteDescription->bundleMid());
-		iceTransport->addRemoteCandidate(candidate);
+
-	} else {
+		if (mRemoteDescription->hasCandidate(candidate))
-		// OK, we might need a lookup, do it asynchronously
+			return; // already in description, ignore
-		// We don't use the thread pool because we have no control on the timeout
+
-		weak_ptr<IceTransport> weakIceTransport{iceTransport};
+		candidate.resolve(Candidate::ResolveMode::Simple);
-		std::thread t([weakIceTransport, candidate]() mutable {
+		mRemoteDescription->addCandidate(candidate);
-			if (candidate.resolve(Candidate::ResolveMode::Lookup))
-				if (auto iceTransport = weakIceTransport.lock())
-					iceTransport->addRemoteCandidate(candidate);
-		});
-		t.detach();
 	}
 
-	mRemoteDescription->addCandidate(std::move(candidate));
+	if (candidate.isResolved()) {
+		iceTransport->addRemoteCandidate(std::move(candidate));
+	} else {
+		// We might need a lookup, do it asynchronously
+		// We don't use the thread pool because we have no control on the timeout
+		if ((iceTransport = std::atomic_load(&mIceTransport))) {
+			weak_ptr<IceTransport> weakIceTransport{iceTransport};
+			std::thread t([weakIceTransport, candidate = std::move(candidate)]() mutable {
+				if (candidate.resolve(Candidate::ResolveMode::Lookup))
+					if (auto iceTransport = weakIceTransport.lock())
+						iceTransport->addRemoteCandidate(std::move(candidate));
+			});
+			t.detach();
+		}
+	}
+}
+
+string PeerConnection::localBundleMid() const {
+	std::lock_guard lock(mLocalDescriptionMutex);
+	return mLocalDescription ? mLocalDescription->bundleMid() : "0";
 }
 
 void PeerConnection::triggerDataChannel(weak_ptr<DataChannel> weakDataChannel) {
@@ -1150,12 +1159,11 @@ void PeerConnection::triggerDataChannel(weak_ptr<DataChannel> weakDataChannel) {
 	if (!dataChannel)
 		return;
 
-	mProcessor->enqueue(
+	mProcessor->enqueue(mDataChannelCallback.wrap(), std::move(dataChannel));
-	    [this, dataChannel = std::move(dataChannel)]() { mDataChannelCallback(dataChannel); });
 }
 
 void PeerConnection::triggerTrack(std::shared_ptr<Track> track) {
-	mProcessor->enqueue([this, track = std::move(track)]() { mTrackCallback(track); });
+	mProcessor->enqueue(mTrackCallback.wrap(), std::move(track));
 }
 
 bool PeerConnection::changeState(State state) {
@@ -1177,7 +1185,7 @@ bool PeerConnection::changeState(State state) {
 		// This is the last state change, so we may steal the callback
 		mProcessor->enqueue([cb = std::move(mStateChangeCallback)]() { cb(State::Closed); });
 	else
-		mProcessor->enqueue([this, state]() { mStateChangeCallback(state); });
+		mProcessor->enqueue(mStateChangeCallback.wrap(), state);
 
 	return true;
 }
@@ -1189,7 +1197,7 @@ bool PeerConnection::changeGatheringState(GatheringState state) {
 	std::ostringstream s;
 	s << state;
 	PLOG_INFO << "Changed gathering state to " << s.str();
-	mProcessor->enqueue([this, state] { mGatheringStateChangeCallback(state); });
+	mProcessor->enqueue(mGatheringStateChangeCallback.wrap(), state);
 	return true;
 }
 
@@ -1200,7 +1208,7 @@ bool PeerConnection::changeSignalingState(SignalingState state) {
 	std::ostringstream s;
 	s << state;
 	PLOG_INFO << "Changed signaling state to " << s.str();
-	mProcessor->enqueue([this, state] { mSignalingStateChangeCallback(state); });
+	mProcessor->enqueue(mSignalingStateChangeCallback.wrap(), state);
 	return true;
 }
 

src/processor.cpp

@@ -20,6 +20,8 @@
 
 namespace rtc {
 
+Processor::Processor(size_t limit) : mTasks(limit) {}
+
 Processor::~Processor() { join(); }
 
 void Processor::join() {
@@ -29,15 +31,13 @@ void Processor::join() {
 
 void Processor::schedule() {
 	std::unique_lock lock(mMutex);
-	if (mTasks.empty()) {
+	if (auto next = mTasks.tryPop()) {
+		ThreadPool::Instance().enqueue(std::move(*next));
+	} else {
 		// No more tasks
 		mPending = false;
 		mCondition.notify_all();
-		return;
 	}
-
-	ThreadPool::Instance().enqueue(std::move(mTasks.front()));
-	mTasks.pop();
 }
 
 } // namespace rtc

src/processor.hpp

@@ -22,6 +22,7 @@
 #include "include.hpp"
 #include "init.hpp"
 #include "threadpool.hpp"
+#include "queue.hpp"
 
 #include <condition_variable>
 #include <future>
@@ -34,7 +35,7 @@ namespace rtc {
 // Processed tasks in order by delegating them to the thread pool
 class Processor final {
 public:
-	Processor() = default;
+	Processor(size_t limit = 0);
 	~Processor();
 
 	Processor(const Processor &) = delete;
@@ -52,7 +53,7 @@ protected:
 	// Keep an init token
 	const init_token mInitToken = Init::Token();
 
-	std::queue<std::function<void()>> mTasks;
+	Queue<std::function<void()>> mTasks;
 	bool mPending = false; // true iff a task is pending in the thread pool
 
 	mutable std::mutex mMutex;
@@ -71,7 +72,7 @@ template <class F, class... Args> void Processor::enqueue(F &&f, Args &&... args
 		ThreadPool::Instance().enqueue(std::move(task));
 		mPending = true;
 	} else {
-		mTasks.emplace(std::move(task));
+		mTasks.push(std::move(task));
 	}
 }
 

src/rtcp.cpp

@@ -126,7 +126,7 @@ bool RtcpReceivingSession::requestKeyframe() {
 
 void RtcpReceivingSession::pushPLI() {
 	auto msg = rtc::make_message(rtc::RTCP_PLI::size(), rtc::Message::Type::Control);
-	auto *pli = (rtc::RTCP_PLI *)msg->data();
+	auto *pli = reinterpret_cast<rtc::RTCP_PLI *>(msg->data());
 	pli->preparePacket(mSsrc);
 	send(msg);
 }

src/sctptransport.cpp

@@ -88,7 +88,7 @@ void SctpTransport::Cleanup() {
 SctpTransport::SctpTransport(std::shared_ptr<Transport> lower, uint16_t port,
                              message_callback recvCallback, amount_callback bufferedAmountCallback,
                              state_callback stateChangeCallback)
-    : Transport(lower, std::move(stateChangeCallback)), mPort(port),
+    : Transport(lower, std::move(stateChangeCallback)), mPort(port), mPendingRecvCount(0),
       mSendQueue(0, message_size_func), mBufferedAmountCallback(std::move(bufferedAmountCallback)) {
 	onRecv(recvCallback);
 
@@ -100,11 +100,12 @@ SctpTransport::SctpTransport(std::shared_ptr<Transport> lower, uint16_t port,
 		Instances.insert(this);
 	}
 
-	mSock = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP, &SctpTransport::RecvCallback,
+	mSock = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP, nullptr, nullptr, 0, nullptr);
-	                       &SctpTransport::SendCallback, 0, this);
 	if (!mSock)
 		throw std::runtime_error("Could not create SCTP socket, errno=" + std::to_string(errno));
 
+	usrsctp_set_upcall(mSock, &SctpTransport::UpcallCallback, this);
+
 	if (usrsctp_set_non_blocking(mSock, 1))
 		throw std::runtime_error("Unable to set non-blocking mode, errno=" + std::to_string(errno));
 
@@ -122,6 +123,10 @@ SctpTransport::SctpTransport(std::shared_ptr<Transport> lower, uint16_t port,
 	if (usrsctp_setsockopt(mSock, IPPROTO_SCTP, SCTP_ENABLE_STREAM_RESET, &av, sizeof(av)))
 		throw std::runtime_error("Could not set socket option SCTP_ENABLE_STREAM_RESET, errno=" +
 		                         std::to_string(errno));
+	int on = 1;
+	if (usrsctp_setsockopt(mSock, IPPROTO_SCTP, SCTP_RECVRCVINFO, &on, sizeof(on)))
+		throw std::runtime_error("Could set socket option SCTP_RECVRCVINFO, errno=" +
+		                         std::to_string(errno));
 
 	struct sctp_event se = {};
 	se.se_assoc_id = SCTP_ALL_ASSOC;
@@ -225,6 +230,7 @@ bool SctpTransport::stop() {
 
 void SctpTransport::close() {
 	if (mSock) {
+		mProcessor.join();
 		usrsctp_close(mSock);
 		mSock = nullptr;
 	}
@@ -319,6 +325,67 @@ void SctpTransport::incoming(message_ptr message) {
 	usrsctp_conninput(this, message->data(), message->size(), 0);
 }
 
+bool SctpTransport::outgoing(message_ptr message) {
+	// Set recommended medium-priority DSCP value
+	// See https://tools.ietf.org/html/draft-ietf-tsvwg-rtcweb-qos-18
+	message->dscp = 10; // AF11: Assured Forwarding class 1, low drop probability
+	return Transport::outgoing(std::move(message));
+}
+
+void SctpTransport::doRecv() {
+	std::lock_guard lock(mRecvMutex);
+	--mPendingRecvCount;
+	try {
+		while (true) {
+			const size_t bufferSize = 65536;
+			byte buffer[bufferSize];
+			socklen_t fromlen = 0;
+			struct sctp_rcvinfo info = {};
+			socklen_t infolen = sizeof(info);
+			unsigned int infotype = 0;
+			int flags = 0;
+			ssize_t len = usrsctp_recvv(mSock, buffer, bufferSize, nullptr, &fromlen, &info,
+			                            &infolen, &infotype, &flags);
+			if (len < 0) {
+				if (errno == EWOULDBLOCK || errno == EAGAIN || errno == ECONNRESET)
+					break;
+				else
+					throw std::runtime_error("SCTP recv failed, errno=" + std::to_string(errno));
+			}
+
+			PLOG_VERBOSE << "SCTP recv, len=" << len;
+
+			// SCTP_FRAGMENT_INTERLEAVE does not seem to work as expected for messages > 64KB,
+			// therefore partial notifications and messages need to be handled separately.
+			if (flags & MSG_NOTIFICATION) {
+				// SCTP event notification
+				mPartialNotification.insert(mPartialNotification.end(), buffer, buffer + len);
+				if (flags & MSG_EOR) {
+					// Notification is complete, process it
+					auto notification =
+					    reinterpret_cast<union sctp_notification *>(mPartialNotification.data());
+					processNotification(notification, mPartialNotification.size());
+					mPartialNotification.clear();
+				}
+			} else {
+				// SCTP message
+				mPartialMessage.insert(mPartialMessage.end(), buffer, buffer + len);
+				if (flags & MSG_EOR) {
+					// Message is complete, process it
+					if (infotype != SCTP_RECVV_RCVINFO)
+						throw std::runtime_error("Missing SCTP recv info");
+
+					processData(std::move(mPartialMessage), info.rcv_sid,
+					            PayloadId(ntohl(info.rcv_ppid)));
+					mPartialMessage.clear();
+				}
+			}
+		}
+	} catch (const std::exception &e) {
+		PLOG_WARNING << e.what();
+	}
+}
+
 bool SctpTransport::trySendQueue() {
 	// Requires mSendMutex to be locked
 	while (auto next = mSendQueue.peek()) {
@@ -472,44 +539,21 @@ bool SctpTransport::safeFlush() {
 	}
 }
 
-int SctpTransport::handleRecv(struct socket * /*sock*/, union sctp_sockstore /*addr*/,
+void SctpTransport::handleUpcall() {
-                              const byte *data, size_t len, struct sctp_rcvinfo info, int flags) {
+	if (!mSock)
-	try {
+		return;
-		PLOG_VERBOSE << "Handle recv, len=" << len;
 
-		// SCTP_FRAGMENT_INTERLEAVE does not seem to work as expected for messages > 64KB,
+	PLOG_VERBOSE << "Handle upcall";
-		// therefore partial notifications and messages need to be handled separately.
-		if (flags & MSG_NOTIFICATION) {
-			// SCTP event notification
-			mPartialNotification.insert(mPartialNotification.end(), data, data + len);
-			if (flags & MSG_EOR) {
-				// Notification is complete, process it
-				processNotification(
-				    reinterpret_cast<const union sctp_notification *>(mPartialNotification.data()),
-				    mPartialNotification.size());
-				mPartialNotification.clear();
-			}
-		} else {
-			// SCTP message
-			mPartialMessage.insert(mPartialMessage.end(), data, data + len);
-			if (flags & MSG_EOR) {
-				// Message is complete, process it
-				processData(std::move(mPartialMessage), info.rcv_sid,
-				            PayloadId(ntohl(info.rcv_ppid)));
-				mPartialMessage.clear();
-			}
-		}
 
-	} catch (const std::exception &e) {
+	int events = usrsctp_get_events(mSock);
-		PLOG_ERROR << "SCTP recv: " << e.what();
+
-		return -1;
+	if (events & SCTP_EVENT_READ && mPendingRecvCount == 0) {
+		++mPendingRecvCount;
+		mProcessor.enqueue(&SctpTransport::doRecv, this);
 	}
-	return 0; // success
-}
 
-int SctpTransport::handleSend(size_t free) {
+	if (events & SCTP_EVENT_WRITE)
-	PLOG_VERBOSE << "Handle send, free=" << free;
+		mProcessor.enqueue(&SctpTransport::safeFlush, this);
-	return safeFlush() ? 0 : -1;
 }
 
 int SctpTransport::handleWrite(byte *data, size_t len, uint8_t /*tos*/, uint8_t /*set_df*/) {
@@ -517,6 +561,7 @@ int SctpTransport::handleWrite(byte *data, size_t len, uint8_t /*tos*/, uint8_t
 		std::unique_lock lock(mWriteMutex);
 		PLOG_VERBOSE << "Handle write, len=" << len;
 
+		auto message = make_message(data, data + len);
 		if (!outgoing(make_message(data, data + len)))
 			return -1;
 
@@ -699,31 +744,14 @@ std::optional<milliseconds> SctpTransport::rtt() {
 	return milliseconds(status.sstat_primary.spinfo_srtt);
 }
 
-int SctpTransport::RecvCallback(struct socket *sock, union sctp_sockstore addr, void *data,
+void SctpTransport::UpcallCallback(struct socket *, void *arg, int /* flags */) {
-                                size_t len, struct sctp_rcvinfo recv_info, int flags,
+	auto *transport = static_cast<SctpTransport *>(arg);
-                                void *ulp_info) {
-	auto *transport = static_cast<SctpTransport *>(ulp_info);
-
-	std::shared_lock lock(InstancesMutex);
-	if (Instances.find(transport) == Instances.end()) {
-		free(data);
-		return -1;
-	}
-
-	int ret =
-	    transport->handleRecv(sock, addr, static_cast<const byte *>(data), len, recv_info, flags);
-	free(data);
-	return ret;
-}
-
-int SctpTransport::SendCallback(struct socket *, uint32_t sb_free, void *ulp_info) {
-	auto *transport = static_cast<SctpTransport *>(ulp_info);
 
 	std::shared_lock lock(InstancesMutex);
 	if (Instances.find(transport) == Instances.end())
-		return -1;
+		return;
 
-	return transport->handleSend(size_t(sb_free));
+	transport->handleUpcall();
 }
 
 int SctpTransport::WriteCallback(void *ptr, void *data, size_t len, uint8_t tos, uint8_t set_df) {

src/sctptransport.hpp

@@ -21,8 +21,10 @@
 
 #include "include.hpp"
 #include "peerconnection.hpp"
+#include "processor.hpp"
 #include "queue.hpp"
 #include "transport.hpp"
+#include "processor.hpp"
 
 #include <condition_variable>
 #include <functional>
@@ -35,7 +37,7 @@
 
 namespace rtc {
 
-class SctpTransport : public Transport {
+class SctpTransport final : public Transport {
 public:
 	static void Init();
 	static void Cleanup();
@@ -75,16 +77,16 @@ private:
 	void shutdown();
 	void close();
 	void incoming(message_ptr message) override;
+	bool outgoing(message_ptr message) override;
 
+	void doRecv();
 	bool trySendQueue();
 	bool trySendMessage(message_ptr message);
 	void updateBufferedAmount(uint16_t streamId, long delta);
 	void sendReset(uint16_t streamId);
 	bool safeFlush();
 
-	int handleRecv(struct socket *sock, union sctp_sockstore addr, const byte *data, size_t len,
+	void handleUpcall();
-	               struct sctp_rcvinfo recv_info, int flags);
-	int handleSend(size_t free);
 	int handleWrite(byte *data, size_t len, uint8_t tos, uint8_t set_df);
 
 	void processData(binary &&data, uint16_t streamId, PayloadId ppid);
@@ -93,7 +95,9 @@ private:
 	const uint16_t mPort;
 	struct socket *mSock;
 
-	std::mutex mSendMutex;
+	Processor mProcessor;
+	std::atomic<int> mPendingRecvCount;
+	std::mutex mRecvMutex, mSendMutex;
 	Queue<message_ptr> mSendQueue;
 	std::map<uint16_t, size_t> mBufferedAmount;
 	amount_callback mBufferedAmountCallback;
@@ -109,9 +113,7 @@ private:
 	// Stats
 	std::atomic<size_t> mBytesSent = 0, mBytesReceived = 0;
 
-	static int RecvCallback(struct socket *sock, union sctp_sockstore addr, void *data, size_t len,
+	static void UpcallCallback(struct socket *sock, void *arg, int flags);
-	                        struct sctp_rcvinfo recv_info, int flags, void *ulp_info);
-	static int SendCallback(struct socket *sock, uint32_t sb_free, void *ulp_info);
 	static int WriteCallback(void *sctp_ptr, void *data, size_t len, uint8_t tos, uint8_t set_df);
 
 	static std::unordered_set<SctpTransport *> Instances;

src/threadpool.cpp

@@ -18,15 +18,26 @@
 
 #include "threadpool.hpp"
 
+#include <cstdlib>
+
+namespace {
+	void joinThreadPoolInstance() {
+		rtc::ThreadPool::Instance().join();
+	}
+}
+
 namespace rtc {
 
 ThreadPool &ThreadPool::Instance() {
-	// Init handles joining on cleanup
 	static ThreadPool *instance = new ThreadPool;
 	return *instance;
 }
 
-ThreadPool::~ThreadPool() { join(); }
+ThreadPool::ThreadPool() {
+	std::atexit(joinThreadPoolInstance);
+}
+
+ThreadPool::~ThreadPool() {}
 
 int ThreadPool::count() const {
 	std::unique_lock lock(mWorkersMutex);

src/threadpool.hpp

@@ -56,7 +56,7 @@ public:
 	auto enqueue(F &&f, Args &&... args) -> invoke_future_t<F, Args...>;
 
 protected:
-	ThreadPool() = default;
+	ThreadPool();
 	~ThreadPool();
 
 	std::function<void()> dequeue(); // returns null function if joining

src/track.cpp

@@ -45,12 +45,30 @@ void Track::close() {
 	setRtcpHandler(nullptr);
 }
 
-bool Track::send(message_variant data) { return outgoing(make_message(std::move(data))); }
+bool Track::send(message_variant data) {
+	if (mIsClosed)
+		throw std::runtime_error("Track is closed");
 
-bool Track::send(const byte *data, size_t size) {
+	auto direction = mMediaDescription.direction();
-	return outgoing(std::make_shared<Message>(data, data + size, Message::Binary));
+	if ((direction == Description::Direction::RecvOnly ||
+	     direction == Description::Direction::Inactive)) {
+		PLOG_WARNING << "Track media direction does not allow transmission, dropping";
+		return false;
+	}
+
+	auto message = make_message(std::move(data));
+
+	if (mRtcpHandler) {
+		message = mRtcpHandler->outgoing(message);
+		if (!message)
+			return false;
+	}
+
+	return outgoing(std::move(message));
 }
 
+bool Track::send(const byte *data, size_t size) { return send(binary(data, data + size)); }
+
 std::optional<message_variant> Track::receive() {
 	if (auto next = mRecvQueue.tryPop())
 		return to_variant(std::move(**next));
@@ -88,50 +106,10 @@ void Track::open(shared_ptr<DtlsSrtpTransport> transport) {
 }
 #endif
 
-bool Track::outgoing(message_ptr message) {
-
-	if (mRtcpHandler) {
-		message = mRtcpHandler->outgoing(message);
-		if (!message)
-			return false;
-	}
-
-	auto direction = mMediaDescription.direction();
-	if ((direction == Description::Direction::RecvOnly ||
-	     direction == Description::Direction::Inactive) &&
-	    message->type != Message::Control) {
-		PLOG_WARNING << "Track media direction does not allow transmission, dropping";
-		return false;
-	}
-
-	if (mIsClosed)
-		throw std::runtime_error("Track is closed");
-
-	if (message->size() > maxMessageSize())
-		throw std::runtime_error("Message size exceeds limit");
-
-#if RTC_ENABLE_MEDIA
-	auto transport = mDtlsSrtpTransport.lock();
-	if (!transport)
-		throw std::runtime_error("Track transport is not open");
-
-	return transport->sendMedia(message);
-#else
-	PLOG_WARNING << "Ignoring track send (not compiled with SRTP support)";
-	return false;
-#endif
-}
-
 void Track::incoming(message_ptr message) {
 	if (!message)
 		return;
 
-	if (mRtcpHandler) {
-		message = mRtcpHandler->incoming(message);
-		if (!message)
-			return;
-	}
-
 	auto direction = mMediaDescription.direction();
 	if ((direction == Description::Direction::SendOnly ||
 	     direction == Description::Direction::Inactive) &&
@@ -140,30 +118,46 @@ void Track::incoming(message_ptr message) {
 		return;
 	}
 
+	if (mRtcpHandler) {
+		message = mRtcpHandler->incoming(message);
+		if (!message)
+			return;
+	}
+
 	// Tail drop if queue is full
-	if (mRecvQueue.full())
+	if (mRecvQueue.full()) {
+		PLOG_WARNING << "Track incoming queue is full, dropping";
 		return;
+	}
 
 	mRecvQueue.push(message);
 	triggerAvailable(mRecvQueue.size());
 }
 
+bool Track::outgoing([[maybe_unused]] message_ptr message) {
+#if RTC_ENABLE_MEDIA
+	auto transport = mDtlsSrtpTransport.lock();
+	if (!transport)
+		throw std::runtime_error("Track transport is not open");
+
+	// Set recommended medium-priority DSCP value
+	// See https://tools.ietf.org/html/draft-ietf-tsvwg-rtcweb-qos-18
+	if (mMediaDescription.type() == "audio")
+		message->dscp = 46; // EF: Expedited Forwarding
+	else
+		message->dscp = 36; // AF42: Assured Forwarding class 4, medium drop probability
+
+	return transport->sendMedia(message);
+#else
+	PLOG_WARNING << "Ignoring track send (not compiled with media support)";
+	return false;
+#endif
+}
+
 void Track::setRtcpHandler(std::shared_ptr<RtcpHandler> handler) {
 	mRtcpHandler = std::move(handler);
-	if (mRtcpHandler) {
+	if (mRtcpHandler)
-		mRtcpHandler->onOutgoing([&]([[maybe_unused]] const rtc::message_ptr &message) {
+		mRtcpHandler->onOutgoing(std::bind(&Track::outgoing, this, std::placeholders::_1));
-#if RTC_ENABLE_MEDIA
-			auto transport = mDtlsSrtpTransport.lock();
-			if (!transport)
-				throw std::runtime_error("Track transport is not open");
-
-			return transport->sendMedia(message);
-#else
-			PLOG_WARNING << "Ignoring track send (not compiled with SRTP support)";
-			return false;
-#endif
-		});
-	}
 }
 
 bool Track::requestKeyframe() {

src/transport.hpp

@@ -28,8 +28,6 @@
 
 namespace rtc {
 
-using namespace std::placeholders;
-
 class Transport {
 public:
 	enum class State { Disconnected, Connecting, Connected, Completed, Failed };
@@ -57,7 +55,7 @@ public:
 	void registerIncoming() {
 		if (mLower) {
 			PLOG_VERBOSE << "Registering incoming callback";
-			mLower->onRecv(std::bind(&Transport::incoming, this, _1));
+			mLower->onRecv(std::bind(&Transport::incoming, this, std::placeholders::_1));
 		}
 	}
 

src/websocket.cpp

@@ -36,6 +36,7 @@
 namespace rtc {
 
 using std::shared_ptr;
+using namespace std::placeholders;
 
 WebSocket::WebSocket(std::optional<Configuration> config)
     : mConfig(config ? std::move(*config) : Configuration()),
@@ -117,6 +118,10 @@ void WebSocket::remoteClose() {
 
 bool WebSocket::send(message_variant data) { return outgoing(make_message(std::move(data))); }
 
+bool WebSocket::send(const byte *data, size_t size) {
+	return outgoing(make_message(data, data + size));
+}
+
 bool WebSocket::isOpen() const { return mState == State::Open; }
 
 bool WebSocket::isClosed() const { return mState == State::Closed; }
@@ -286,8 +291,14 @@ shared_ptr<WsTransport> WebSocket::initWsTransport() {
 		shared_ptr<Transport> lower = std::atomic_load(&mTlsTransport);
 		if (!lower)
 			lower = std::atomic_load(&mTcpTransport);
+
+		WsTransport::Configuration wsConfig = {};
+		wsConfig.host = mHost;
+		wsConfig.path = mPath;
+		wsConfig.protocols = mConfig.protocols;
+
 		auto transport = std::make_shared<WsTransport>(
-		    lower, mHost, mPath, weak_bind(&WebSocket::incoming, this, _1),
+			lower, wsConfig, weak_bind(&WebSocket::incoming, this, _1),
 		    [this, weak_this = weak_from_this()](State state) {
 			    auto shared_this = weak_this.lock();
 			    if (!shared_this)

src/wstransport.cpp

@@ -24,8 +24,10 @@
 #if RTC_ENABLE_WEBSOCKET
 
 #include <chrono>
+#include <iterator>
 #include <list>
 #include <map>
+#include <numeric>
 #include <random>
 #include <regex>
 
@@ -52,17 +54,17 @@ using std::to_string;
 using random_bytes_engine =
     std::independent_bits_engine<std::default_random_engine, CHAR_BIT, unsigned short>;
 
-WsTransport::WsTransport(std::shared_ptr<Transport> lower, string host, string path,
+WsTransport::WsTransport(std::shared_ptr<Transport> lower, Configuration config,
                          message_callback recvCallback, state_callback stateCallback)
-    : Transport(lower, std::move(stateCallback)), mHost(std::move(host)), mPath(std::move(path)) {
+    : Transport(lower, std::move(stateCallback)), mConfig(std::move(config)) {
 	onRecv(recvCallback);
 
 	PLOG_DEBUG << "Initializing WebSocket transport";
 
-	if (mHost.empty())
+	if (mConfig.host.empty())
 		throw std::invalid_argument("WebSocket HTTP host cannot be empty");
 
-	if (mPath.empty())
+	if (mConfig.path.empty())
 		throw std::invalid_argument("WebSocket HTTP path cannot be empty");
 }
 
@@ -153,7 +155,7 @@ void WsTransport::close() {
 }
 
 bool WsTransport::sendHttpRequest() {
-	PLOG_DEBUG << "Sending WebSocket HTTP request for path " << mPath;
+	PLOG_DEBUG << "Sending WebSocket HTTP request for path " << mConfig.path;
 	changeState(State::Connecting);
 
 	auto seed = static_cast<unsigned int>(system_clock::now().time_since_epoch().count());
@@ -163,18 +165,27 @@ bool WsTransport::sendHttpRequest() {
 	auto k = reinterpret_cast<uint8_t *>(key.data());
 	std::generate(k, k + key.size(), [&]() { return uint8_t(generator()); });
 
-	const string request = "GET " + mPath +
+	string appendHeader = "";
+	if (mConfig.protocols.size() > 0) {
+		appendHeader +=
+		    "Sec-WebSocket-Protocol: " +
+		    std::accumulate(mConfig.protocols.begin(), mConfig.protocols.end(), string(),
+		                    [](const string &a, const string &b) -> string {
+			                    return a + (a.length() > 0 ? "," : "") + b;
+		                    }) +
+		    "\r\n";
+	}
+
+	const string request = "GET " + mConfig.path +
 	                       " HTTP/1.1\r\n"
 	                       "Host: " +
-	                       mHost +
+	                       mConfig.host +
 	                       "\r\n"
 	                       "Connection: Upgrade\r\n"
 	                       "Upgrade: websocket\r\n"
 	                       "Sec-WebSocket-Version: 13\r\n"
 	                       "Sec-WebSocket-Key: " +
-	                       to_base64(key) +
+	                       to_base64(key) + "\r\n" + std::move(appendHeader) + "\r\n";
-	                       "\r\n"
-	                       "\r\n";
 
 	auto data = reinterpret_cast<const byte *>(request.data());
 	auto size = request.size();
@@ -227,8 +238,14 @@ size_t WsTransport::readHttpResponse(const byte *buffer, size_t size) {
 	}
 
 	auto h = headers.find("upgrade");
-	if (h == headers.end() || h->second != "websocket")
+	if (h == headers.end())
-		throw std::runtime_error("WebSocket update header missing or mismatching");
+		throw std::runtime_error("WebSocket update header missing");
+
+	string upgrade;
+	std::transform(h->second.begin(), h->second.end(), std::back_inserter(upgrade),
+	               [](char c) { return std::tolower(c); });
+	if (upgrade != "websocket")
+		throw std::runtime_error("WebSocket update header mismatching: " + h->second);
 
 	h = headers.find("sec-websocket-accept");
 	if (h == headers.end())

src/wstransport.hpp

@@ -31,7 +31,13 @@ class TlsTransport;
 
 class WsTransport : public Transport {
 public:
-	WsTransport(std::shared_ptr<Transport> lower, string host, string path,
+	struct Configuration {
+		string host;
+		string path = "/";
+		std::vector<string> protocols;
+	};
+
+	WsTransport(std::shared_ptr<Transport> lower, Configuration config,
 	            message_callback recvCallback, state_callback stateCallback);
 	~WsTransport();
 
@@ -68,12 +74,12 @@ private:
 	void recvFrame(const Frame &frame);
 	bool sendFrame(const Frame &frame);
 
-	const string mHost;
+	const Configuration mConfig;
-	const string mPath;
 
 	binary mBuffer;
 	binary mPartial;
 	Opcode mPartialOpcode;
+
 };
 
 } // namespace rtc

test/capi_connectivity.cpp

@@ -100,14 +100,48 @@ static void RTC_API messageCallback(int id, const char *message, int size, void
 
 static void RTC_API dataChannelCallback(int pc, int dc, void *ptr) {
 	Peer *peer = (Peer *)ptr;
-	peer->dc = dc;
+
-	peer->connected = true;
+	char label[256];
+	if (rtcGetDataChannelLabel(dc, label, 256) < 0) {
+		fprintf(stderr, "rtcGetDataChannelLabel failed\n");
+		return;
+	}
+
+	char protocol[256];
+	if (rtcGetDataChannelProtocol(dc, protocol, 256) < 0) {
+		fprintf(stderr, "rtcGetDataChannelProtocol failed\n");
+		return;
+	}
+
+	rtcReliability reliability;
+	if (rtcGetDataChannelReliability(dc, &reliability) < 0) {
+		fprintf(stderr, "rtcGetDataChannelReliability failed\n");
+		return;
+	}
+
+	printf("DataChannel %d: Received with label \"%s\" and protocol \"%s\"\n",
+	       peer == peer1 ? 1 : 2, label, protocol);
+
+	if (strcmp(label, "test") != 0) {
+		fprintf(stderr, "Wrong DataChannel label\n");
+		return;
+	}
+
+	if (strcmp(protocol, "protocol") != 0) {
+		fprintf(stderr, "Wrong DataChannel protocol\n");
+		return;
+	}
+
+	if (reliability.unordered == false) {
+		fprintf(stderr, "Wrong DataChannel reliability\n");
+		return;
+	}
+
 	rtcSetClosedCallback(dc, closedCallback);
 	rtcSetMessageCallback(dc, messageCallback);
 
-	char buffer[256];
+	peer->dc = dc;
-	if (rtcGetDataChannelLabel(dc, buffer, 256) >= 0)
+	peer->connected = true;
-		printf("DataChannel %d: Received with label \"%s\"\n", peer == peer1 ? 1 : 2, buffer);
 
 	const char *message = peer == peer1 ? "Hello from 1" : "Hello from 2";
 	rtcSendMessage(peer->dc, message, -1); // negative size indicates a null-terminated string
@@ -127,6 +161,7 @@ static Peer *createPeer(const rtcConfiguration *config) {
 	rtcSetLocalCandidateCallback(peer->pc, candidateCallback);
 	rtcSetStateChangeCallback(peer->pc, stateChangeCallback);
 	rtcSetGatheringStateChangeCallback(peer->pc, gatheringStateCallback);
+	rtcSetSignalingStateChangeCallback(peer->pc, signalingStateCallback);
 
 	return peer;
 }
@@ -173,7 +208,12 @@ int test_capi_connectivity_main() {
 		goto error;
 
 	// Peer 1: Create data channel
-	peer1->dc = rtcCreateDataChannel(peer1->pc, "test");
+	rtcDataChannelInit init;
+	memset(&init, 0, sizeof(init));
+	init.protocol = "protocol";
+	init.reliability.unordered = true;
+
+	peer1->dc = rtcCreateDataChannelEx(peer1->pc, "test", &init);
 	rtcSetOpenCallback(peer1->dc, openCallback);
 	rtcSetClosedCallback(peer1->dc, closedCallback);
 	rtcSetMessageCallback(peer1->dc, messageCallback);
@@ -187,12 +227,6 @@ int test_capi_connectivity_main() {
 		goto error;
 	}
 
-	if (peer1->signalingState != RTC_SIGNALING_STABLE ||
-	    peer2->signalingState != RTC_SIGNALING_STABLE) {
-		fprintf(stderr, "Signaling state is not stable\n");
-		goto error;
-	}
-
 	if (!peer1->connected || !peer2->connected) {
 		fprintf(stderr, "DataChannel is not connected\n");
 		goto error;