ws2_32: Move the setsockopt(IP_DONTFRAGMENT) implementation to ntdll.

dlls/ntdll/unix/socket.c

@@ -1717,6 +1717,25 @@ NTSTATUS sock_ioctl( HANDLE handle, HANDLE event, PIO_APC_ROUTINE apc, void *apc
             return STATUS_SUCCESS;
         }
 
+        case IOCTL_AFD_WINE_SET_IP_DONTFRAGMENT:
+#ifdef IP_DONTFRAG
+            return do_setsockopt( handle, io, IPPROTO_IP, IP_DONTFRAG, in_buffer, in_size );
+#elif defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO) && defined(IP_PMTUDISC_DONT)
+        {
+            int value = *(DWORD *)in_buffer ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT;
+
+            return do_setsockopt( handle, io, IPPROTO_IP, IP_MTU_DISCOVER, &value, sizeof(value) );
+        }
+#else
+        {
+            static int once;
+
+            if (!once++)
+                FIXME( "IP_DONTFRAGMENT is not supported on this platform\n" );
+            return STATUS_SUCCESS; /* fake success */
+        }
+#endif
+
         default:
         {
             if ((code >> 16) == FILE_DEVICE_NETWORK)

dlls/ws2_32/socket.c

@@ -3634,6 +3634,9 @@ int WINAPI WS_setsockopt(SOCKET s, int level, int optname,
         case WS_IP_BLOCK_SOURCE:
             return server_setsockopt( s, IOCTL_AFD_WINE_SET_IP_BLOCK_SOURCE, optval, optlen );
 
+        case WS_IP_DONTFRAGMENT:
+            return server_setsockopt( s, IOCTL_AFD_WINE_SET_IP_DONTFRAGMENT, optval, optlen );
+
         case WS_IP_DROP_SOURCE_MEMBERSHIP:
         case WS_IP_UNBLOCK_SOURCE:
         {
@@ -3666,8 +3669,7 @@ int WINAPI WS_setsockopt(SOCKET s, int level, int optname,
 #endif
             convert_sockopt(&level, &optname);
             break;
-        case WS_IP_DONTFRAGMENT:
-            return set_dont_fragment(s, IPPROTO_IP, *(BOOL *)optval) ? 0 : SOCKET_ERROR;
+
         default:
             FIXME("Unknown IPPROTO_IP optname 0x%08x\n", optname);
             return SOCKET_ERROR;

include/wine/afd.h

@@ -185,6 +185,7 @@ struct afd_get_events_params
 #define IOCTL_AFD_WINE_SET_IP_ADD_SOURCE_MEMBERSHIP     WINE_AFD_IOC(240)
 #define IOCTL_AFD_WINE_SET_IP_BLOCK_SOURCE              WINE_AFD_IOC(241)
 #define IOCTL_AFD_WINE_GET_IP_DONTFRAGMENT              WINE_AFD_IOC(242)
+#define IOCTL_AFD_WINE_SET_IP_DONTFRAGMENT              WINE_AFD_IOC(243)
 
 struct afd_create_params
 {