'ipv6' type in /etc/protocols ?

From: Luigi Rizzo (rizzo_at_icir.org)
Date: 01/14/04

  • Next message: John Hay: "Re: 'ipv6' type in /etc/protocols ?" 
    Date: Wed, 14 Jan 2004 01:29:13 -0800
To: net@freebsd.org

    hi,
    in implementing ipv6 support for ipfw2, i hit the following
    problem: /etc/protocols has an entry:

            ipv6 41 IPV6 # ipv6

    which is somewhat confusing for the parser -- if you
    type something like

            ipfw add allow ipv6 from foo to bar

    the "ipv6" will match in the call to getprotobyname() and
    the above will be translated into a rule that matches packets with
    ip->ip_proto == 41 (6 is TCP, 17 is UDP, etc.), while i presume
    that what one would really want with the above notation is to
    match IPv6 packets, i.e.

      + layer2 packets with mac-type 0x86dd (ipv6)
      + layer3 packets with ip->ip_v == 6

    Now, i can put a special case for the keyword 'ipv6', but
    I wonder, what do we do with ip->ip_proto == 41 ? Does it
    make sense to handle this request ? And in this case,
    what name do we use for it to avoid conflicts ?
    Looking at /sys/netinet/in.h, it appears that
    ip_proto == 4 and 41 refer to encapsulations of ipv4 and ipv6
    into ip...

            cheers
            luigi

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  • Next message: John Hay: "Re: 'ipv6' type in /etc/protocols ?"