Fix connection failure on iOS when connecting to a Tailscale IPv4 add…

…ress from an IPv6-only mobile network such as T-Mobile. T-Mobile handles IPv4 addresses, including the special 100.x.x.x Tailscale addresses, using 464xlat and NAT64. We need to force resolve the address using AF_INET instead of AF_UNSPEC in order to get a usable address to connect to. More info: https://en.wikipedia.org/wiki/IPv6_transition_mechanism#464XLAT
moonlight-stream · Dec 2, 2024 · bc67221 · bc67221
1 parent d3d3e6c
commit bc67221
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Showing 2 changed files with 23 additions and 9 deletions.
diff --git a/src/Connection.c b/src/Connection.c
@@ -136,7 +136,7 @@ void LiStopConnection(void) {
         Limelog("done\n");
     }
     LC_ASSERT(stage == STAGE_NONE);
-    
+
     if (RemoteAddrString != NULL) {
         free(RemoteAddrString);
         RemoteAddrString = NULL;
@@ -281,7 +281,7 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
 
     alreadyTerminated = false;
     ConnectionInterrupted = false;
-    
+
     // Validate the audio configuration
     if (MAGIC_BYTE_FROM_AUDIO_CONFIG(StreamConfig.audioConfiguration) != 0xCA ||
             CHANNEL_COUNT_FROM_AUDIO_CONFIGURATION(StreamConfig.audioConfiguration) > AUDIO_CONFIGURATION_MAX_CHANNEL_COUNT) {
@@ -328,7 +328,7 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
         Limelog("Disabling reference frame invalidation for 4K streaming with GFE\n");
         VideoCallbacks.capabilities &= ~CAPABILITY_REFERENCE_FRAME_INVALIDATION_AVC;
     }
-    
+
     Limelog("Initializing platform...");
     ListenerCallbacks.stageStarting(STAGE_PLATFORM_INIT);
     err = initializePlatform();
@@ -348,13 +348,13 @@ 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, &AddrLen);
+        err = resolveHostName(serverInfo->address, AF_INET, 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, &AddrLen);
+            err = resolveHostName(serverInfo->address, AF_INET, RtspPortNumber, &RemoteAddr, &AddrLen);
         }
     }
     else {
@@ -364,12 +364,12 @@ 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, &AddrLen);
+        err = resolveHostName(serverInfo->address, AF_INET, 47984, &RemoteAddr, &AddrLen);
         if (err != 0) {
-            err = resolveHostName(serverInfo->address, AF_UNSPEC, 47989, &RemoteAddr, &AddrLen);
+            err = resolveHostName(serverInfo->address, AF_INET, 47989, &RemoteAddr, &AddrLen);
         }
         if (err != 0) {
-            err = resolveHostName(serverInfo->address, AF_UNSPEC, 48010, &RemoteAddr, &AddrLen);
+            err = resolveHostName(serverInfo->address, AF_INET, 48010, &RemoteAddr, &AddrLen);
         }
     }
     if (err != 0) {
@@ -517,7 +517,7 @@ int LiStartConnection(PSERVER_INFORMATION serverInfo, PSTREAM_CONFIGURATION stre
     LC_ASSERT(stage == STAGE_INPUT_STREAM_START);
     ListenerCallbacks.stageComplete(STAGE_INPUT_STREAM_START);
     Limelog("done\n");
-    
+
     // Wiggle the mouse a bit to wake the display up
     LiSendMouseMoveEvent(1, 1);
     PltSleepMs(10);

diff --git a/src/PlatformSockets.c b/src/PlatformSockets.c
@@ -600,6 +600,18 @@ int enableNoDelay(SOCKET s) {
     return 0;
 }
 
+static void logWithSockaddr(const char *format, const char *arg, const struct sockaddr *addr, socklen_t len) {
+    char host[NI_MAXHOST], service[NI_MAXSERV];
+    int res = getnameinfo(addr, len, host, sizeof(host), service, sizeof(service),
+                          NI_NUMERICHOST | NI_NUMERICSERV);
+    if (res == 0) {
+        Limelog(format, arg, host, service);
+    }
+    else {
+        Limelog("getnameinfo() failed: %s\n", gai_strerror(res));
+    }
+}
+
 int resolveHostName(const char* host, int family, int tcpTestPort, struct sockaddr_storage* addr, SOCKADDR_LEN* addrLen)
 {
     struct addrinfo hints, *res, *currentAddr;
@@ -638,6 +650,8 @@ int resolveHostName(const char* host, int family, int tcpTestPort, struct sockad
             }
         }
 
+        logWithSockaddr("Resolved %s to %s %s", host, currentAddr->ai_addr, sizeof(currentAddr->ai_addr));
+
         memcpy(addr, currentAddr->ai_addr, currentAddr->ai_addrlen);
         *addrLen = (SOCKADDR_LEN)currentAddr->ai_addrlen;