Prevent anything from updating our own UDP address.

Because we don't want to keep track of that, and this will cause the node
structure from being relinked into the node tree, which results in myself
pointing to an invalid address.

src/net_packet.c

@@ -581,6 +581,9 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
 	for(node = edge_weight_tree->head; node; node = node->next) {
 		e = node->data;
 
+		if(e->to == myself)
+			continue;
+
 		if(sockaddrcmp_noport(from, &e->address)) {
 			if(last_hard_try == now)
 				continue;

src/node.c

@@ -141,6 +141,11 @@ node_t *lookup_node_udp(const sockaddr_t *sa) {
 }
 
 void update_node_udp(node_t *n, const sockaddr_t *sa) {
+	if(n == myself) {
+		logger(LOG_WARNING, "Trying to update UDP address of myself!\n");
+		return;
+	}
+
 	avl_delete(node_udp_tree, n);
 
 	if(n->hostname)