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Date: Mon, 23 Jul 2001 20:01:33 -0700
From: Julian Elischer <julian@elischer.org>
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To: Brooks Davis <brooks@one-eyed-alien.net>
Cc: net@freebsd.org
Subject: Re: error in ip_checkinterface code?
References: <20010723184418.B28097@Odin.AC.HMC.Edu>
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Brooks Davis wrote:
> 
> I just ran into what appears to be a bug in the ip_checkinterface code.
> The problem is that is assumes m->m_pkthdr.rcvif is non-NULL.
> Apparently this is normally true, but I have some netgraph code that
> processes it's processes in such a way that they lose their interface
> pointer which means that when I stick them back into the ip_stack get a
> panic.  A quick patch that fixes the problem is included below.  Is
> this fix correct?
> 
> -- Brooks
> 
> Index: ip_input.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet/ip_input.c,v
> retrieving revision 1.174
> diff -u -r1.174 ip_input.c
> --- ip_input.c  2001/06/23 17:17:58     1.174
> +++ ip_input.c  2001/07/24 01:46:22
> @@ -559,6 +559,7 @@
>          * the packets are received.
>          */
>         checkif = ip_checkinterface && (ipforwarding == 0) &&
> +           m->m_pkthdr.rcvif != NULL &&
>             ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
>             (ip_fw_fwd_addr == NULL);

another possibility is to assign an incoming interface to the reinjected packet
:-)

(what are you using netgraph for?)


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