kern/89472: ipfw2 no longer supports filtering IPv6-over-IPv4 on 6.0-RELEASE

[Hajimu UMEMOTO]

The following reply was made to PR kern/89472; it has been noted by GNATS.

From: Hajimu UMEMOTO <ume at freebsd.org>
To: Gael Roualland <gael.roualland at dial.oleane.com>
Cc: FreeBSD-gnats-submit at freebsd.org, freebsd-ipfw at freebsd.org
Subject: Re: kern/89472: ipfw2 no longer supports filtering IPv6-over-IPv4 on 6.0-RELEASE
Date: Sun, 27 Nov 2005 05:19:01 +0900

 Hi,
 
 >>>>> On Wed, 23 Nov 2005 22:43:07 +0100 (CET)
 >>>>> Gael Roualland <gael.roualland at dial.oleane.com> said:
 
 gael>  Hum, I didn't notice the "ipv6" string was handled a bit differently
 gael>  than the numeric proto number in ipfw.
 
 gael>  It does work, at least IPv6-over-IPv4 packets are not blocked, but ipfw
 gael>  list/show reports the rule as "allow ip from a.b.c.d to me" and it does
 gael>  filter it that way, opening a lot more than just protocol 41...
 
 Umm, 41 is treated as ipv6, internally.  With following patch,
 
 	allow ip from a.b.c.d to me proto 41
 
 should work for workaround.  However, it is still incomplete, and
 `ipfw show' shows
 
 	allow ip from any to any proto ipv6
 
 Apart from this limitation, it seems working to me here.
 
 Index: sbin/ipfw/ipfw2.c
 diff -u -p sbin/ipfw/ipfw2.c.orig sbin/ipfw/ipfw2.c
 --- sbin/ipfw/ipfw2.c.orig	Sat Aug 20 17:36:57 2005
 +++ sbin/ipfw/ipfw2.c	Sun Nov 27 04:18:43 2005
 @@ -3611,7 +3611,8 @@ add_proto(ipfw_insn *cmd, char *av, u_ch
  		*proto = pe->p_proto;
  	else
  		return NULL;
 -	if (*proto != IPPROTO_IP && *proto != IPPROTO_IPV6)
 +	if (strcmp(av, "ipv4") != 0 && strcmp(av, "ip4") != 0 &&
 +	    strcmp(av, "ipv6") != 0 && strcmp(av, "ip6") != 0)
  		fill_cmd(cmd, O_PROTO, 0, *proto);
  
  	return cmd;
 
 
 Sincerely,
 
 --
 Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan
 ume at mahoroba.org  ume@{,jp.}FreeBSD.org
 http://www.imasy.org/~ume/