This patch changes printk to add helpful information...i.e. who to 
firewall etc.  It is against 2.4.18-rc1.  IPV6 needs one too but in my 
opinion, a similar NIPQUAD macro needs built and the IPV6 core in 
general needs a tidying up to use the new macro.

--- linux/net/ipv4/udp.c.orig Thu Feb 14 13:38:24 2002
+++ linux/net/ipv4/udp.c      Thu Feb 14 13:32:34 2002
@@ -928,7 +928,14 @@
        return(0);
 
 short_packet:
-       NETDEBUG(if (net_ratelimit()) printk(KERN_DEBUG "UDP: short 
packet: %d/%d\n", ulen, len));
+       NETDEBUG(if (net_ratelimit())
+               printk(KERN_DEBUG "UDP: short packet: %u.%u.%u.%u:%u 
%d/%d to %u.%u.%u.%u:%u\n",
+                       NIPQUAD(saddr),
+                       ntohs(uh->source),
+                       ulen,
+                       len,
+                       NIPQUAD(daddr),
+                       ntohs(uh->dest)));
 no_header:
        UDP_INC_STATS_BH(UdpInErrors);
        kfree_skb(skb);