Re: icmp hdr incorrect in skbuff

[Ola Nordstrom <ola@triblock.com>]

On Mon, Nov 11, 2002 at 09:14:35AM +0100, Patrick Schaaf wrote:
> > (*skb)->h.icmph->type
> 
> Where did you get the idea that h.icmph would be set sensibly
> inside netfilter hooks? What hook, exactly, are you talking
> about? Your description doesn't say that clearly, and it could
> be crucial to know.
nf_register_hook(&post_routing_ops)
> 
> My gut guess would be that h.icmph would only be set correctly when
> the icmp parts of the Linux network stack had their hands on the
> skbuff under inspection.
> 
> In other words, I would expect it to be valid only for echo replies
> sent by the machine itself.
> 
> Conceptually, to me, the netfilter hooks used by iptables sit
> at the IP layer. Access to other layers must be implemented
> locally in iptables match/target code, by working up from
> the IP header (or down, to get at L2 framing, if that exists).

Ok. I was under the impression that the headers above IP would be set
properly inside the skbuff aswell. None of the docs really made this
clear.

> 
> Hope this helps. If I'm not talking sense, somebody shoot the argument.

Yes. Thanks!

-Ola