BSD: do not attempt atomic route changes.

This is buggy on OS X, at least. As for linux we choose to be safe and
we deactivate atomic route changes on all BSDs.

kernel_socket.c

@@ -422,21 +422,17 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
        memcmp(newgate, gate, 16) == 0 && newifindex == ifindex)
       return 0;
 
+
     if(operation == ROUTE_MODIFY) {
-        /* Do not use ROUTE_MODIFY when changing to a neighbour.
-           It is the only way to remove the "gateway" flag. */
-        if(ipv4 && plen == 128 && memcmp(dest, newgate, 16) == 0) {
-            kernel_route(ROUTE_FLUSH, dest, plen,
-                         gate, ifindex, metric,
-                         NULL, 0, 0);
-            return kernel_route(ROUTE_ADD, dest, plen,
-                                newgate, newifindex, newmetric,
-                                NULL, 0, 0);
-        } else {
-            metric = newmetric;
-            gate = newgate;
-            ifindex = newifindex;
-        }
+
+        /* Avoid atomic route changes that is buggy on OS X. */
+        kernel_route(ROUTE_FLUSH, dest, plen,
+                     gate, ifindex, metric,
+                     NULL, 0, 0);
+        return kernel_route(ROUTE_ADD, dest, plen,
+                            newgate, newifindex, newmetric,
+                            NULL, 0, 0);
+
     }
 
     kdebugf("kernel_route: %s %s/%d metric %d dev %d nexthop %s\n",