$NetBSD: patch-ai,v 1.2 2010/07/24 13:42:12 obache Exp $

--- avahi-core/server.c.orig	2010-06-29 18:51:53.000000000 +0000
+++ avahi-core/server.c
@@ -903,6 +903,11 @@ static void dispatch_packet(AvahiServer 
         return;
     }
 
+    if (port <= 0) {
+        avahi_log_warn("Received packet from invalid source port.");
+        return;
+    }
+
     if (avahi_address_is_ipv4_in_ipv6(src_address))
         /* This is an IPv4 address encapsulated in IPv6, so let's ignore it. */
         return;