IPv6 support for LibVNCServer, part three: make reverse connections IPv6-capable.

Besided making libvncserver reverseVNC IPv6-aware, this introduces some changes
on the client side as well to make clients listen on IPv6 sockets, too. Like
the server side, this also uses a separate-socket approach.

client_examples/SDLvncviewer.c

@@ -518,6 +518,7 @@ int main(int argc,char** argv) {
 	  cl->HandleTextChat=text_chat;
 	  cl->GotXCutText = got_selection;
 	  cl->listenPort = LISTEN_PORT_OFFSET;
+	  cl->listen6Port = LISTEN_PORT_OFFSET;
 	  if(!rfbInitClient(cl,&argc,argv))
 	    {
 	      cl = NULL; /* rfbInitClient has already freed the client struct */

libvncclient/listen.c

@@ -50,7 +50,7 @@ listenForIncomingConnections(rfbClient* client)
   rfbClientErr("listenForIncomingConnections on MinGW32 NOT IMPLEMENTED\n");
   return;
 #else
-  int listenSocket;
+  int listenSocket, listen6Socket = -1;
   fd_set fds;
 
   client->listenSpecified = TRUE;
@@ -65,8 +65,24 @@ listenForIncomingConnections(rfbClient* client)
   rfbClientLog("%s -listen: Command line errors are not reported until "
 	  "a connection comes in.\n", client->programName);
 
-  while (TRUE) {
+#ifdef LIBVNCSERVER_IPv6 /* only try that if we're IPv6-capable, otherwise we may try to bind to the same port which would make all that listening fail */ 
+  /* only do IPv6 listen of listen6Port is set */
+  if (client->listen6Port > 0)
+    {
+      listen6Socket = ListenAtTcpPortAndAddress(client->listen6Port, client->listen6Address);
+
+      if (listen6Socket < 0)
+	return;
+
+      rfbClientLog("%s -listen: Listening on IPV6 port %d\n",
+		   client->programName,client->listenPort);
+      rfbClientLog("%s -listen: Command line errors are not reported until "
+		   "a connection comes in.\n", client->programName);
+    }
+#endif
 
+  while (TRUE) {
+    int r;
     /* reap any zombies */
     int status, pid;
     while ((pid= wait3(&status, WNOHANG, (struct rusage *)0))>0);
@@ -75,12 +91,19 @@ listenForIncomingConnections(rfbClient* client)
 
     FD_ZERO(&fds); 
 
+    if(listenSocket >= 0)
       FD_SET(listenSocket, &fds);  
+    if(listen6Socket >= 0)
+      FD_SET(listen6Socket, &fds);
+
+    r = select(max(listenSocket, listen6Socket)+1, &fds, NULL, NULL, NULL);
 
-    select(listenSocket+1, &fds, NULL, NULL, NULL);
+    if (r > 0) {
+      if (FD_ISSET(listenSocket, &fds))
+	client->sock = AcceptTcpConnection(client->listenSock); 
+      else if (FD_ISSET(listen6Socket, &fds))
+	client->sock = AcceptTcpConnection(client->listen6Sock);
 
-    if (FD_ISSET(listenSocket, &fds)) {
-      client->sock = AcceptTcpConnection(listenSocket);
       if (client->sock < 0)
 	return;
       if (!SetNonBlocking(client->sock))
@@ -97,6 +120,7 @@ listenForIncomingConnections(rfbClient* client)
       case 0:
 	/* child - return to caller */
 	close(listenSocket);
+	close(listen6Socket);
 	return;
 
       default:
@@ -144,24 +168,54 @@ listenForIncomingConnectionsNoFork(rfbClient* client, int timeout)
 		   "a connection comes in.\n", client->programName);
     }
 
+#ifdef LIBVNCSERVER_IPv6 /* only try that if we're IPv6-capable, otherwise we may try to bind to the same port which would make all that listening fail */ 
+  /* only do IPv6 listen of listen6Port is set */
+  if (client->listen6Port > 0 && client->listen6Sock < 0)
+    {
+      client->listen6Sock = ListenAtTcpPortAndAddress(client->listen6Port, client->listen6Address);
+
+      if (client->listen6Sock < 0)
+	return -1;
+
+      rfbClientLog("%s -listennofork: Listening on IPV6 port %d\n",
+		   client->programName,client->listenPort);
+      rfbClientLog("%s -listennofork: Command line errors are not reported until "
+		   "a connection comes in.\n", client->programName);
+    }
+#endif
+
   FD_ZERO(&fds);
 
+  if(client->listenSock >= 0)
     FD_SET(client->listenSock, &fds);
+  if(client->listen6Sock >= 0)
+    FD_SET(client->listen6Sock, &fds);
 
   if (timeout < 0)
-    r = select(client->listenSock+1, &fds, NULL, NULL, NULL);
+    r = select(max(client->listenSock, client->listen6Sock) +1, &fds, NULL, NULL, NULL);
   else
-    r = select(client->listenSock+1, &fds, NULL, NULL, &to);
+    r = select(max(client->listenSock, client->listen6Sock) +1, &fds, NULL, NULL, &to);
 
   if (r > 0)
     {
+      if (FD_ISSET(client->listenSock, &fds))
 	client->sock = AcceptTcpConnection(client->listenSock); 
+      else if (FD_ISSET(client->listen6Sock, &fds))
+	client->sock = AcceptTcpConnection(client->listen6Sock);
+
       if (client->sock < 0)
 	return -1;
       if (!SetNonBlocking(client->sock))
 	return -1;
 
+      if(client->listenSock >= 0) {
 	close(client->listenSock);
+	client->listenSock = -1;
+      }
+      if(client->listen6Sock >= 0) {
+	close(client->listen6Sock);
+	client->listen6Sock = -1;
+      }
       return r;
     }
 

libvncclient/sockets.c

@@ -494,8 +494,9 @@ int
 ListenAtTcpPortAndAddress(int port, const char *address)
 {
   int sock;
-  struct sockaddr_in addr;
   int one = 1;
+#ifndef LIBVNCSERVER_IPv6
+  struct sockaddr_in addr;
 
   addr.sin_family = AF_INET;
   addr.sin_port = htons(port);
@@ -527,6 +528,66 @@ ListenAtTcpPortAndAddress(int port, const char *address)
     return -1;
   }
 
+#else
+  int rv;
+  struct addrinfo hints, *servinfo, *p;
+  char port_str[8];
+
+  snprintf(port_str, 8, "%d", port);
+
+  memset(&hints, 0, sizeof(hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_flags = AI_PASSIVE; /* fill in wildcard address if address == NULL */
+
+  if (!initSockets())
+    return -1;
+
+  if ((rv = getaddrinfo(address, port_str, &hints, &servinfo)) != 0) {
+    rfbClientErr("ListenAtTcpPortAndAddress: error in getaddrinfo: %s\n", gai_strerror(rv));
+    return -1;
+  }
+
+  /* loop through all the results and bind to the first we can */
+  for(p = servinfo; p != NULL; p = p->ai_next) {
+    if ((sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) < 0) {
+      continue;
+    }
+
+#ifdef IPV6_V6ONLY
+    /* we have seperate IPv4 and IPv6 sockets since some OS's do not support dual binding */
+    if (p->ai_family == AF_INET6 && setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&one, sizeof(one)) < 0) {
+      rfbClientErr("ListenAtTcpPortAndAddress: error in setsockopt IPV6_V6ONLY: %s\n", strerror(errno));
+      close(sock);
+      freeaddrinfo(servinfo);
+      return -1;
+    }
+#endif
+
+    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one)) < 0) {
+      rfbClientErr("ListenAtTcpPortAndAddress: error in setsockopt SO_REUSEADDR: %s\n", strerror(errno));
+      close(sock);
+      freeaddrinfo(servinfo);
+      return -1;
+    }
+
+    if (bind(sock, p->ai_addr, p->ai_addrlen) < 0) {
+      close(sock);
+      continue;
+    }
+
+    break;
+  }
+
+  if (p == NULL)  {
+    rfbClientErr("ListenAtTcpPortAndAddress: error in bind: %s\n", strerror(errno));
+    return -1;
+  }
+
+  /* all done with this structure now */
+  freeaddrinfo(servinfo);
+#endif
+
   if (listen(sock, 5) < 0) {
     rfbClientErr("ListenAtTcpPort: listen\n");
     close(sock);

libvncclient/vncviewer.c

@@ -197,6 +197,8 @@ rfbClient* rfbGetClient(int bitsPerSample,int samplesPerPixel,
   client->sock = -1;
   client->listenSock = -1;
   client->listenAddress = NULL;
+  client->listen6Sock = -1;
+  client->listen6Address = NULL;
   client->clientAuthSchemes = NULL;
   return client;
 }

libvncserver/sockets.c

@@ -937,8 +937,46 @@ int
 rfbConnectToTcpAddr(char *host,
                     int port)
 {
-    struct hostent *hp;
     int sock;
+#ifdef LIBVNCSERVER_IPv6
+    struct addrinfo hints, *servinfo, *p;
+    int rv;
+    char port_str[8];
+
+    snprintf(port_str, 8, "%d", port);
+
+    memset(&hints, 0, sizeof hints);
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+
+    if ((rv = getaddrinfo(host, port_str, &hints, &servinfo)) != 0) {
+        rfbErr("rfbConnectToTcpAddr: error in getaddrinfo: %s\n", gai_strerror(rv));
+        return -1;
+    }
+
+    /* loop through all the results and connect to the first we can */
+    for(p = servinfo; p != NULL; p = p->ai_next) {
+        if ((sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) < 0)
+            continue;
+
+        if (connect(sock, p->ai_addr, p->ai_addrlen) < 0) {
+            closesocket(sock);
+            continue;
+        }
+
+        break;
+    }
+
+    /* all failed */
+    if (p == NULL) {
+        rfbLogPerror("rfbConnectToTcoAddr: failed to connect\n");
+        sock = -1; /* set return value */
+    }
+
+    /* all done with this structure now */
+    freeaddrinfo(servinfo);
+#else
+    struct hostent *hp;
     struct sockaddr_in addr;
 
     memset(&addr, 0, sizeof(addr));
@@ -962,7 +1000,7 @@ rfbConnectToTcpAddr(char *host,
 	closesocket(sock);
 	return -1;
     }
-
+#endif
     return sock;
 }
 

rfb/rfbclient.h

@@ -347,7 +347,10 @@ typedef struct _rfbClient {
 	FinishedFrameBufferUpdateProc FinishedFrameBufferUpdate;
 
 	char *listenAddress;
-
+        /* IPv6 listen socket, address and port*/
+        int listen6Sock;
+        char* listen6Address;
+        int listen6Port;
 } rfbClient;
 
 /* cursor.c */