- uint32_t source,dest;
- /* Manufacture and send NAK packet */
- source=get_uint32(st->rbuf->start); /* Us */
- dest=get_uint32(st->rbuf->start+4); /* Them */
- Message(M_INFO,"udp (port %d): sending NAK\n",st->port);
- buffer_init(st->rbuf,0);
- buf_append_uint32(st->rbuf,dest);
- buf_append_uint32(st->rbuf,source);
- buf_append_uint32(st->rbuf,0); /* NAK is msg type 0 */
- sendto(st->fd, st->rbuf->start, st->rbuf->size, 0,
- (struct sockaddr *)&from, sizeof(from));
+ uint32_t msgtype;
+ if (st->rbuf->size>12 /* prevents traffic amplification */
+ && ((msgtype=get_uint32(st->rbuf->start+8))
+ != LABEL_NAK)) {
+ uint32_t source,dest;
+ /* Manufacture and send NAK packet */
+ source=get_uint32(st->rbuf->start); /* Us */
+ dest=get_uint32(st->rbuf->start+4); /* Them */
+ send_nak(&ca,source,dest,msgtype,st->rbuf,"unwanted");
+ }