Bind our UDP sockets to the same local address used by RTSP handshake

This means we can ensure a consistent local address for our outgoing PING
traffic to keep the UDP flows alive without having to call connect() which breaks
with multi-homed hosts on GFE and Sunshine v0.20 and earlier.

src/AudioStream.c

@@ -75,13 +75,6 @@ int initializeAudioStream(void) {
     memcpy(&avRiKeyId, StreamConfig.remoteInputAesIv, sizeof(avRiKeyId));
     avRiKeyId = BE32(avRiKeyId);
 
-    // For GFE 3.22 compatibility, we must start the audio ping thread before the RTSP handshake.
-    // It will not reply to our RTSP PLAY request until the audio ping has been received.
-    rtpSocket = bindUdpSocket(RemoteAddr.ss_family, 0);
-    if (rtpSocket == INVALID_SOCKET) {
-        return LastSocketFail();
-    }
-
     return 0;
 }
 
@@ -92,8 +85,15 @@ int notifyAudioPortNegotiationComplete(void) {
     LC_ASSERT(!pingThreadStarted);
     LC_ASSERT(AudioPortNumber != 0);
 
+    // For GFE 3.22 compatibility, we must start the audio ping thread before the RTSP handshake.
+    // It will not reply to our RTSP PLAY request until the audio ping has been received.
+    rtpSocket = bindUdpSocket(RemoteAddr.ss_family, &LocalAddr, AddrLen, 0);
+    if (rtpSocket == INVALID_SOCKET) {
+        return LastSocketFail();
+    }
+
     // Connect our audio socket to the target address and port
-    int err = connectUdpSocket(rtpSocket, &RemoteAddr, RemoteAddrLen, AudioPortNumber);
+    int err = connectUdpSocket(rtpSocket, &RemoteAddr, AddrLen, AudioPortNumber);
     if (err != 0) {
         return err;
     }

src/Connection.c

@@ -9,7 +9,8 @@ static int terminationCallbackErrorCode;
 // Common globals
 char* RemoteAddrString;
 struct sockaddr_storage RemoteAddr;
-SOCKADDR_LEN RemoteAddrLen;
+struct sockaddr_storage LocalAddr;
+SOCKADDR_LEN AddrLen;
 int AppVersionQuad[4];
 STREAM_CONFIGURATION StreamConfig;
 CONNECTION_LISTENER_CALLBACKS ListenerCallbacks;
@@ -254,6 +255,7 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
     memcpy(&ListenerCallbacks, clCallbacks, sizeof(ListenerCallbacks));
     ListenerCallbacks.connectionTerminated = ClInternalConnectionTerminated;
 
+    memset(&LocalAddr, 0, sizeof(LocalAddr));
     NegotiatedVideoFormat = 0;
     memcpy(&StreamConfig, streamConfig, sizeof(StreamConfig));
     OriginalVideoBitrate = streamConfig->bitrate;
@@ -344,13 +346,13 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
     if (RtspPortNumber != 48010) {
         // If we have an alternate RTSP port, use that as our test port. The host probably
         // isn't listening on 47989 or 47984 anyway, since they're using alternate ports.
-        err = resolveHostName(serverInfo->address, AF_UNSPEC, RtspPortNumber, &RemoteAddr, &RemoteAddrLen);
+        err = resolveHostName(serverInfo->address, AF_UNSPEC, RtspPortNumber, &RemoteAddr, &AddrLen);
         if (err != 0) {
             // Sleep for a second and try again. It's possible that we've attempt to connect
             // before the host has gotten around to listening on the RTSP port. Give it some
             // time before retrying.
             PltSleepMs(1000);
-            err = resolveHostName(serverInfo->address, AF_UNSPEC, RtspPortNumber, &RemoteAddr, &RemoteAddrLen);
+            err = resolveHostName(serverInfo->address, AF_UNSPEC, RtspPortNumber, &RemoteAddr, &AddrLen);
         }
     }
     else {
@@ -360,12 +362,12 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
         // TCP 48010 is a last resort because:
         // a) it's not always listening and there's a race between listen() on the host and our connect()
         // b) it's not used at all by certain host versions which perform RTSP over ENet
-        err = resolveHostName(serverInfo->address, AF_UNSPEC, 47984, &RemoteAddr, &RemoteAddrLen);
+        err = resolveHostName(serverInfo->address, AF_UNSPEC, 47984, &RemoteAddr, &AddrLen);
         if (err != 0) {
-            err = resolveHostName(serverInfo->address, AF_UNSPEC, 47989, &RemoteAddr, &RemoteAddrLen);
+            err = resolveHostName(serverInfo->address, AF_UNSPEC, 47989, &RemoteAddr, &AddrLen);
         }
         if (err != 0) {
-            err = resolveHostName(serverInfo->address, AF_UNSPEC, 48010, &RemoteAddr, &RemoteAddrLen);
+            err = resolveHostName(serverInfo->address, AF_UNSPEC, 48010, &RemoteAddr, &AddrLen);
         }
     }
     if (err != 0) {

src/ControlStream.c

@@ -1597,7 +1597,7 @@ int startControlStream(void) {
         
         LC_ASSERT(ControlPortNumber != 0);
 
-        enet_address_set_address(&address, (struct sockaddr *)&RemoteAddr, RemoteAddrLen);
+        enet_address_set_address(&address, (struct sockaddr *)&RemoteAddr, AddrLen);
         enet_address_set_port(&address, ControlPortNumber);
 
         // Create a client
@@ -1665,7 +1665,7 @@ int startControlStream(void) {
     else {
         // NB: Do NOT use ControlPortNumber here. 47995 is correct for these old versions.
         LC_ASSERT(ControlPortNumber == 0);
-        ctlSock = connectTcpSocket(&RemoteAddr, RemoteAddrLen,
+        ctlSock = connectTcpSocket(&RemoteAddr, AddrLen,
             47995, CONTROL_STREAM_TIMEOUT_SEC);
         if (ctlSock == INVALID_SOCKET) {
             stopping = true;

src/InputStream.c

@@ -699,7 +699,7 @@ int startInputStream(void) {
 
     // After Gen 5, we send input on the control stream
     if (AppVersionQuad[0] < 5) {
-        inputSock = connectTcpSocket(&RemoteAddr, RemoteAddrLen,
+        inputSock = connectTcpSocket(&RemoteAddr, AddrLen,
             35043, INPUT_STREAM_TIMEOUT_SEC);
         if (inputSock == INVALID_SOCKET) {
             return LastSocketFail();

src/Limelight-internal.h

@@ -16,7 +16,8 @@
 // Common globals
 extern char* RemoteAddrString;
 extern struct sockaddr_storage RemoteAddr;
-extern SOCKADDR_LEN RemoteAddrLen;
+extern struct sockaddr_storage LocalAddr;
+extern SOCKADDR_LEN AddrLen;
 extern int AppVersionQuad[4];
 extern STREAM_CONFIGURATION StreamConfig;
 extern CONNECTION_LISTENER_CALLBACKS ListenerCallbacks;

src/PlatformSockets.c

@@ -220,28 +220,36 @@ void closeSocket(SOCKET s) {
 #endif
 }
 
-SOCKET bindUdpSocket(int addrfamily, int bufferSize) {
+SOCKET bindUdpSocket(int addressFamily, struct sockaddr_storage* localAddr, SOCKADDR_LEN addrLen, int bufferSize) {
     SOCKET s;
-    struct sockaddr_storage addr;
+    LC_SOCKADDR bindAddr;
     int err;
-    SOCKADDR_LEN addrLen;
 
-#ifdef AF_INET6
+    s = createSocket(addressFamily, SOCK_DGRAM, IPPROTO_UDP, false);
-    LC_ASSERT(addrfamily == AF_INET || addrfamily == AF_INET6);
-    addrLen = (addrfamily == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6));
-#else
-    LC_ASSERT(addrfamily == AF_INET);
-    addrLen = sizeof(struct sockaddr_in);
-#endif
-
-    s = createSocket(addrfamily, SOCK_DGRAM, IPPROTO_UDP, false);
     if (s == INVALID_SOCKET) {
         return INVALID_SOCKET;
     }
 
-    memset(&addr, 0, sizeof(addr));
+    // Use localAddr to bind if it was provided
-    addr.ss_family = addrfamily;
+    if (localAddr && localAddr->ss_family != 0) {
-    if (bind(s, (struct sockaddr*) &addr, addrLen) == SOCKET_ERROR) {
+        memcpy(&bindAddr, localAddr, addrLen);
+        SET_PORT(&bindAddr, 0);
+    }
+    else {
+        // Otherwise wildcard bind to the specified address family
+        memset(&bindAddr, 0, sizeof(bindAddr));
+        SET_FAMILY(&bindAddr, addressFamily);
+
+#ifdef AF_INET6
+        LC_ASSERT(addressFamily == AF_INET || addressFamily == AF_INET6);
+        addrLen = (addressFamily == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6));
+#else
+        LC_ASSERT(addressFamily == AF_INET);
+        addrLen = sizeof(struct sockaddr_in);
+#endif
+    }
+
+    if (bind(s, (struct sockaddr*) &bindAddr, addrLen) == SOCKET_ERROR) {
         err = LastSocketError();
         Limelog("bind() failed: %d\n", err);
         closeSocket(s);

src/PlatformSockets.h

@@ -68,9 +68,11 @@ typedef socklen_t SOCKADDR_LEN;
 
 #ifdef AF_INET6
 typedef struct sockaddr_in6 LC_SOCKADDR;
+#define SET_FAMILY(addr, family) ((addr)->sin6_family = (family))
 #define SET_PORT(addr, port) ((addr)->sin6_port = htons(port))
 #else
 typedef struct sockaddr_in LC_SOCKADDR;
+#define SET_FAMILY(addr, family) ((addr)->sin_family = (family))
 #define SET_PORT(addr, port) ((addr)->sin_port = htons(port))
 #endif
 
@@ -88,7 +90,7 @@ SOCKET createSocket(int addressFamily, int socketType, int protocol, bool nonBlo
 SOCKET connectTcpSocket(struct sockaddr_storage* dstaddr, SOCKADDR_LEN addrlen, unsigned short port, int timeoutSec);
 int connectUdpSocket(SOCKET s, struct sockaddr_storage* dstaddr, SOCKADDR_LEN addrlen, unsigned short port);
 int sendMtuSafe(SOCKET s, char* buffer, int size);
-SOCKET bindUdpSocket(int addrfamily, int bufferSize);
+SOCKET bindUdpSocket(int addressFamily, struct sockaddr_storage* localAddr, SOCKADDR_LEN addrLen, int bufferSize);
 int enableNoDelay(SOCKET s);
 int setSocketNonBlocking(SOCKET s, bool enabled);
 int recvUdpSocket(SOCKET s, char* buffer, int size, bool useSelect);

src/RtspConnection.c

@@ -229,7 +229,7 @@ static bool transactRtspMessageTcp(PRTSP_MESSAGE request, PRTSP_MESSAGE response
     // returns HTTP 200 OK for the /launch request before the RTSP handshake port
     // is listening.
     do {
-        sock = connectTcpSocket(&RemoteAddr, RemoteAddrLen, RtspPortNumber, RTSP_CONNECT_TIMEOUT_SEC);
+        sock = connectTcpSocket(&RemoteAddr, AddrLen, RtspPortNumber, RTSP_CONNECT_TIMEOUT_SEC);
         if (sock == INVALID_SOCKET) {
             *error = LastSocketError();
             if (*error == ECONNREFUSED) {
@@ -320,6 +320,18 @@ static bool transactRtspMessageTcp(PRTSP_MESSAGE request, PRTSP_MESSAGE response
         Limelog("Failed to parse RTSP response\n");
     }
 
+    // Fetch the local address for this socket if it's not populated yet
+    if (LocalAddr.ss_family == 0) {
+        SOCKADDR_LEN addrLen = (SOCKADDR_LEN)sizeof(LocalAddr);
+        if (getsockname(sock, (struct sockaddr*)&LocalAddr, &addrLen) < 0) {
+            Limelog("Failed to get local address: %d\n", LastSocketError());
+            memset(&LocalAddr, 0, sizeof(LocalAddr));
+        }
+        else {
+            LC_ASSERT(addrLen == AddrLen);
+        }
+    }
+
 Exit:
     if (serializedMessage != NULL) {
         free(serializedMessage);
@@ -819,7 +831,7 @@ int performRtspHandshake(PSERVER_INFORMATION serverInfo) {
         ENetAddress address;
         ENetEvent event;
         
-        enet_address_set_address(&address, (struct sockaddr *)&RemoteAddr, RemoteAddrLen);
+        enet_address_set_address(&address, (struct sockaddr *)&RemoteAddr, AddrLen);
         enet_address_set_port(&address, RtspPortNumber);
         
         // Create a client that can use 1 outgoing connection and 1 channel

src/SimpleStun.c

@@ -73,7 +73,7 @@ int LiFindExternalAddressIP4(const char* stunServer, unsigned short stunPort, un
         goto Exit;
     }
 
-    sock = bindUdpSocket(hints.ai_family, 0);
+    sock = bindUdpSocket(hints.ai_family, NULL, 0, 0);
     if (sock == INVALID_SOCKET) {
         err = LastSocketFail();
         Limelog("Failed to connect to STUN server: %d\n", err);

src/VideoStream.c

@@ -261,7 +261,8 @@ int startVideoStream(void* rendererContext, int drFlags) {
         return err;
     }
 
-    rtpSocket = bindUdpSocket(RemoteAddr.ss_family, RTP_RECV_PACKETS_BUFFERED * (StreamConfig.packetSize + MAX_RTP_HEADER_SIZE));
+    rtpSocket = bindUdpSocket(RemoteAddr.ss_family, &LocalAddr, AddrLen,
+                              RTP_RECV_PACKETS_BUFFERED * (StreamConfig.packetSize + MAX_RTP_HEADER_SIZE));
     if (rtpSocket == INVALID_SOCKET) {
         VideoCallbacks.cleanup();
         return LastSocketError();
@@ -269,7 +270,7 @@ int startVideoStream(void* rendererContext, int drFlags) {
 
     // Connect our video socket to the target address and port
     LC_ASSERT(VideoPortNumber != 0);
-    err = connectUdpSocket(rtpSocket, &RemoteAddr, RemoteAddrLen, VideoPortNumber);
+    err = connectUdpSocket(rtpSocket, &RemoteAddr, AddrLen, VideoPortNumber);
     if (err != 0) {
         VideoCallbacks.cleanup();
         closeSocket(rtpSocket);
@@ -301,7 +302,7 @@ int startVideoStream(void* rendererContext, int drFlags) {
 
     if (AppVersionQuad[0] == 3) {
         // Connect this socket to open port 47998 for our ping thread
-        firstFrameSocket = connectTcpSocket(&RemoteAddr, RemoteAddrLen,
+        firstFrameSocket = connectTcpSocket(&RemoteAddr, AddrLen,
                                             FIRST_FRAME_PORT, FIRST_FRAME_TIMEOUT_SEC);
         if (firstFrameSocket == INVALID_SOCKET) {
             VideoCallbacks.stop();