IP QoS support in libvncclient.

This enables setting the DSCP/Traffic Class field of IP/IPv6 packets
sent by a client. For example starting a client with -qosdscp 184
marks all outgoing traffic for expedited forwarding.

Implementation for Win32 is still a TODO, though. See
http://betelco.blogspot.com/2009/03/dscp-marking-under-windows-at.html
for an overview of the Win32 QoS API mess...

3 files changed, 56 insertions, 0 deletions

diff --git a/libvncclient/rfbproto.c b/libvncclient/rfbproto.c
index df8eb2f..602594b 100644
--- a/libvncclient/rfbproto.c
+++ b/libvncclient/rfbproto.c
@@ -421,6 +421,9 @@ ConnectToRFBServer(rfbClient* client,const char *hostname, int port)
     return FALSE;
   }
 
+  if(client->QoS_DSCP && !SetDSCP(client->sock, client->QoS_DSCP))
+     return FALSE;
+
   return SetNonBlocking(client->sock);
 }
 
diff --git a/libvncclient/sockets.c b/libvncclient/sockets.c
index 28b0256..e9a4b53 100644
--- a/libvncclient/sockets.c
+++ b/libvncclient/sockets.c
@@ -566,6 +566,55 @@ SetNonBlocking(int sock)
 }
 
 
+
+/*
+ * SetDSCP sets a socket's IP QoS parameters aka Differentiated Services Code Point field
+ */
+
+rfbBool
+SetDSCP(int sock, int dscp)
+{
+#ifdef WIN32
+  rfbClientErr("Setting of QoS IP DSCP not implemented for Windows\n");
+  return TRUE;
+#else
+  int level, cmd;
+  struct sockaddr addr;
+  socklen_t addrlen = sizeof(addr);
+
+  if(getsockname(sock, &addr, &addrlen) != 0) {
+    rfbClientErr("Setting socket QoS failed while getting socket address: %s\n",strerror(errno));
+    return FALSE;
+  }
+
+  switch(addr.sa_family)
+    {
+#ifdef LIBVNCSERVER_IPv6
+    case AF_INET6:
+      level = IPPROTO_IPV6;
+      cmd = IPV6_TCLASS;
+      break;
+#endif
+    case AF_INET:
+      level = IPPROTO_IP;
+      cmd = IP_TOS;
+      break;
+    default:
+      rfbClientErr("Setting socket QoS failed: Not bound to IP address");
+      return FALSE;
+    }
+
+  if(setsockopt(sock, level, cmd, (void*)&dscp, sizeof(dscp)) != 0) {
+    rfbClientErr("Setting socket QoS failed: %s\n", strerror(errno));
+    return FALSE;
+  }
+
+  return TRUE;
+#endif
+}
+
+
+
 /*
  * StringToIPAddr - convert a host string to an IP address.
  */
diff --git a/libvncclient/vncviewer.c b/libvncclient/vncviewer.c
index 6541c1d..1c5ea6e 100644
--- a/libvncclient/vncviewer.c
+++ b/libvncclient/vncviewer.c
@@ -186,6 +186,7 @@ rfbClient* rfbGetClient(int bitsPerSample,int samplesPerPixel,
   client->Bell = Dummy;
   client->CurrentKeyboardLedState = 0;
   client->HandleKeyboardLedState = (HandleKeyboardLedStateProc)DummyPoint;
+  client->QoS_DSCP = 0;
 
   client->authScheme = 0;
   client->subAuthScheme = 0;
@@ -288,6 +289,9 @@ rfbBool rfbInitClient(rfbClient* client,int* argc,char** argv) {
       } else if (i+1<*argc && strcmp(argv[i], "-scale") == 0) {
         client->appData.scaleSetting = atoi(argv[i+1]);
         j+=2;
+      } else if (i+1<*argc && strcmp(argv[i], "-qosdscp") == 0) {
+        client->QoS_DSCP = atoi(argv[i+1]);
+        j+=2;
       } else if (i+1<*argc && strcmp(argv[i], "-repeaterdest") == 0) {
 	char* colon=strchr(argv[i+1],':');