Re: [PATCH] icmpv6 match --icmpv6-type confusion

[Patrick McHardy <kaber@trash.net>]

Yasuyuki KOZAKAI wrote:
> From: Patrick McHardy <kaber@trash.net>
> Subject: Re: [PATCH] icmpv6 match --icmpv6-type confusion
> Date: Mon, 03 Jul 2006 19:52:23 +0200
>>Phil Oester wrote:
>>
>>>Adding a rule such as this:
>>>
>>>-A INPUT -p ipv6-icmp -m icmpv6
>>>
>>>ends up creating a rule with "ipv6-icmp type 0", instead of "ipv6-icmp type any"
>>>which is what was expected.  Granted, the match is redundant anyway, but it
>>>should not assume a specific type when one is not specified.
>>>
>>>Below patches (to both kernel and userspace) fix this, and resolve bug #461.
>>>In keeping with icmpv4, 0xFF is used to designate "any". And since I was
>>>looking at it, I fixed up a 255 -> any in icmpv4 printing.
>>
>>Thanks Phil. I have to admit that I never liked the ugly 255 hack,
>>its a perfectly valid value for the type field to use, even though
>>its currently not defined for IPv4 or IPv6. For IPv6 I even have
>>some concerns that it will stay unused for all times, the stategy
>>for choosing new values seems to be different from IPv4. I guess
>>an alternative would be to introduce a new revision.
>>
>>Yasuyuki, do you have an opinion on this?
> 
> 
> It sounds good to me to introduce a new revision and a new value to support
> "icmpv6-type any". But can we really break behavior compatibility of
> "-p ipv6-icmp -m icmpv6" ?


I tend to agree with Phil's interpretation that this is actually
unexpected behaviour, so I don't think anyone is doing this
intentional. I would expect either a parser error or type any.