Special-case IPv4 in really_send_update.

message.c

@@ -526,6 +526,9 @@ really_send_update(struct network *net,
                    unsigned short seqno, unsigned short metric)
 {
     if(!export_filter(address, prefix, plen)) {
+        if(plen >= 96 && v4mapped(prefix)) {
+            ;
+        } else {
             if(in_prefix(address, prefix, plen)) {
                 send_message(net, 3, plen, 0, seqno, metric, address);
             } else {
@@ -537,6 +540,7 @@ really_send_update(struct network *net,
                 send_message(net, 4, plen, 0, seqno, metric, prefix);
             }
         }
+    }
     satisfy_request(prefix, plen, seqno, hash_id(address), net);
 }