Add ToS option to sockets.

Creates a new SocketOption called called TypeOfServiceOption that can be
used with the existing setSocketOption method to set the ToS byte in a
socket socket. This is done only for unix systems because windows
doesn't support directly setting the ToS/DSCP byte:
http://support.microsoft.com/kb/248611
http://blogs.msdn.com/b/wndp/archive/2006/07/05/657196.aspx

Change-Id: Idf9da2dd8307ac7057982fbfdf9e4e9ebe366780
Task-number: QTBUG-6221
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Peter Hartmann <peter.hartmann@nokia.com>

src/network/socket/qabstractsocket.cpp

@@ -360,6 +360,19 @@
 
     \value MulticastLoopbackOption Set this to 1 to enable the IP_MULTICAST_LOOP (multicast loopback) socket option.
 
+    \value TypeOfServiceOption This option is not supported on Windows. This maps to to the IP_TOS socket option. Possible values are:
+    \table
+    \header \o Value \o Description
+    \row \o 224 \o Network control
+    \row \o 192 \o Internetwork control
+    \row \o 160 \o CRITIC/ECP
+    \row \o 128 \o Flash override
+    \row \o 96 \o Flash
+    \row \o 64 \o Immediate
+    \row \o 32 \o Priority
+    \row \o 0 \o Routine
+    \endtable
+
     \sa QAbstractSocket::setSocketOption(), QAbstractSocket::socketOption()
 */
 
@@ -1805,6 +1818,10 @@ void QAbstractSocket::setSocketOption(QAbstractSocket::SocketOption option, cons
         case MulticastLoopbackOption:
                 d_func()->socketEngine->setOption(QAbstractSocketEngine::MulticastLoopbackOption, value.toInt());
                 break;
+
+        case TypeOfServiceOption:
+            d_func()->socketEngine->setOption(QAbstractSocketEngine::TypeOfServiceOption, value.toInt());
+            break;
     }
 }
 
@@ -1841,6 +1858,10 @@ QVariant QAbstractSocket::socketOption(QAbstractSocket::SocketOption option)
         case MulticastLoopbackOption:
                 ret = d_func()->socketEngine->option(QAbstractSocketEngine::MulticastLoopbackOption);
                 break;
+
+        case TypeOfServiceOption:
+                ret = d_func()->socketEngine->option(QAbstractSocketEngine::TypeOfServiceOption);
+                break;
     }
     if (ret == -1)
         return QVariant();

src/network/socket/qabstractsocket.h

@@ -113,7 +113,8 @@ public:
         LowDelayOption, // TCP_NODELAY
         KeepAliveOption, // SO_KEEPALIVE
         MulticastTtlOption, // IP_MULTICAST_TTL
-        MulticastLoopbackOption // IP_MULTICAST_LOOPBACK
+        MulticastLoopbackOption, // IP_MULTICAST_LOOPBACK
+        TypeOfServiceOption //IP_TOS
     };
     enum BindFlag {
         DefaultForPlatform = 0x0,

src/network/socket/qabstractsocketengine_p.h

@@ -99,7 +99,8 @@ public:
         LowDelayOption,
         KeepAliveOption,
         MulticastTtlOption,
-        MulticastLoopbackOption
+        MulticastLoopbackOption,
+        TypeOfServiceOption
     };
 
     virtual bool initialize(QAbstractSocket::SocketType type, QAbstractSocket::NetworkLayerProtocol protocol = QAbstractSocket::IPv4Protocol) = 0;

src/network/socket/qnativesocketengine_unix.cpp

@@ -251,6 +251,12 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
             n = IP_MULTICAST_LOOP;
         }
         break;
+    case QNativeSocketEngine::TypeOfServiceOption:
+        if (socketProtocol == QAbstractSocket::IPv4Protocol) {
+            level = IPPROTO_IP;
+            n = IP_TOS;
+        }
+        break;
     }
 
     int v = -1;
@@ -352,6 +358,12 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
             n = IP_MULTICAST_LOOP;
         }
         break;
+    case QNativeSocketEngine::TypeOfServiceOption:
+        if (socketProtocol == QAbstractSocket::IPv4Protocol) {
+            level = IPPROTO_IP;
+            n = IP_TOS;
+        }
+        break;
     }
 
     return ::setsockopt(socketDescriptor, level, n, (char *) &v, sizeof(v)) == 0;

src/network/socket/qnativesocketengine_win.cpp

@@ -422,6 +422,9 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
             n = IP_MULTICAST_LOOP;
         }
         break;
+    case QNativeSocketEngine::TypeOfServiceOption:
+        return -1;
+        break;
     }
 
     int v = -1;
@@ -502,6 +505,9 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
             n = IP_MULTICAST_LOOP;
         }
         break;
+    case QNativeSocketEngine::TypeOfServiceOption:
+        return false;
+        break;
     }
 
     if (::setsockopt(socketDescriptor, level, n, (char*)&v, sizeof(v)) != 0) {