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From: ormonde@trem.cnt.org.br (Rodrigo Ormonde)
Message-Id: <9605221807.AA08687@trem.cnt.org.br>
Subject: NULL interface field in ip_fw_chk
To: freebsd-hackers@freebsd.org
Date: Wed, 22 May 1996 15:07:11 -0300 (GRNLNDST)
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Hi folks. 
  
  I'm working in the ip_fw.c module in the FreeBSD 2.1. There is a function
in this module called ip_fw_chk that returns TRUE or FALSE if the ip packet
that it receives should or not be accepted (i.e. routed by ip).
  This function receives 4 parameters and one of them is a pointer to a
structure that holds information about the interface the packet comes from. The
prototype of the function is:

int ip_fw_chk(mbuf *m, struct ip *ip, struct ifnet *rif, ...
 
   Looking into the code of ip_fw_chk, I realise that sometimes this function
is called with rif = NULL.

   My question is: does anybody knows why and under what circunstances the
ip_fw_chk is called with a NULL pointer in the interface field ? (the 
ip_fw_chk function is called only by ip_input.c)

   Thanks in advance for your help.

-- 
Rodrigo de La Rocque Ormonde
Confederacao Nacional do Transporte 
e-mail: ormonde@cnt.org.br