Implement support for FIONREAD in WSPIoctl. (hope I did it properly)

It works correctly with the wininet I'll commit later and a test app I wrote myself.

svn path=/trunk/; revision=33787

reactos/dll/win32/msafd/misc/dllmain.c

@@ -1517,6 +1517,9 @@ WSPIoctl(
 				Handle, Socket->SharedData.NonBlocking));
 	return 0;
 
+    case FIONREAD:
+        return GetSocketInformation(Socket, AFD_INFO_RECEIVE_CONTENT_SIZE, (PULONG)lpvOutBuffer, NULL);
+
     default:
 	*lpErrno = WSAEINVAL;
 	return SOCKET_ERROR;

reactos/drivers/network/afd/afd/info.c

@@ -48,6 +48,14 @@ AfdGetInfo( PDEVICE_OBJECT DeviceObject, PIRP Irp,
 	    InfoReq->Information.Ulong = 0;
 	    break;
 
+    case AFD_INFO_RECEIVE_CONTENT_SIZE:
+        /* Only touch InfoReq if we actually have a valid connection.
+           Behaviour was verified under WinXP SP2. */
+        if(FCB->Connection.Handle)
+            InfoReq->Information.Ulong = FCB->Recv.Content - FCB->Recv.BytesUsed;
+
+        break;
+
 	default:
 	    AFD_DbgPrint(MID_TRACE,("Unknown info id %x\n",
 				    InfoReq->InformationClass));

reactos/include/reactos/drivers/afd/shared.h

@@ -149,6 +149,7 @@ typedef struct _AFD_DISCONNECT_INFO {
 #define AFD_INFO_RECEIVE_WINDOW_SIZE	0x06L
 #define AFD_INFO_SEND_WINDOW_SIZE	0x07L
 #define AFD_INFO_GROUP_ID_TYPE	        0x10L
+#define AFD_INFO_RECEIVE_CONTENT_SIZE   0x11L
 
 /* AFD Share Flags */
 #define AFD_SHARE_UNIQUE		0x0L