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Date:      Wed, 10 Oct 2001 18:06:21 -0700 (PDT)
From:      Archie Cobbs <archie@dellroad.org>
To:        John Polstra <jdp@polstra.com>
Cc:        net@FreeBSD.ORG, aihguo1@hotmail.com
Subject:   Re: Trying to find out which interface an IP packet is coming from in ip_output() routine
Message-ID:  <200110110106.f9B16L514629@arch20m.dellroad.org>
In-Reply-To: <200110101618.f9AGIVA86599@vashon.polstra.com> "from John Polstra at Oct 10, 2001 09:18:31 am"

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John Polstra writes:
> >    Can anybody help me find a way to find out which interface an IP
> > packet is coming from in ip_output()/ip_input() routine?
> 
> The mb->m_pkthdr.rcvif field of the mbuf points to the interface on
> which the packet was received.

...if any. In ip_input(), mb->m_pkthdr.rcvif is always non-NULL,
but in ip_output() it may be NULL e.g. if the packet was locally
generated.

-Archie

__________________________________________________________________________
Archie Cobbs     *     Packet Design     *     http://www.packetdesign.com

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