*** ip_output.c.orig	Sat Nov  1 04:53:02 1997
--- ip_output.c	Sat Nov  1 04:56:47 1997
***************
*** 60,65 ****
--- 60,69 ----
  static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *));
  static void ip_mloopback
  	__P((struct ifnet *, struct mbuf *, struct sockaddr_in *));
+ #if defined(IPFILTER)
+ extern int fr_check __P((struct ip *, int, struct ifnet *, int, struct mbuf **));
+ extern int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **));
+ #endif
  
  /*
   * IP output.  The packet in mbuf chain m contains a skeletal IP
***************
*** 313,318 ****
--- 317,331 ----
  	} else
  		mtu = ifp->if_mtu;
  
+ #if defined(IPFILTER)
+ 	if (fr_checkp) {
+ 		struct mbuf *m1 = m;
+ 
+ 		if ((error = (*fr_checkp)(ip, hlen, ifp, 1, &m1)) || !m1)
+ 			goto done;
+ 		ip = mtod(m = m1, struct ip *);
+ 	}
+ #endif
  	/*
  	 * If small enough for route, can just send directly.
  	 */