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if.c revision 1.7 
      1 /*	$NetBSD: if.c,v 1.7 1995/03/18 15:00:28 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)if.c	8.1 (Berkeley) 6/5/93";
     39 #else
     40 static char rcsid[] = "$NetBSD: if.c,v 1.7 1995/03/18 15:00:28 cgd Exp $";
     41 #endif
     42 #endif /* not lint */
     43 
     44 /*
     45  * Routing Table Management Daemon
     46  */
     47 #include "defs.h"
     48 
     49 extern	struct interface *ifnet;
     50 
     51 /*
     52  * Find the interface with address addr.
     53  */
     54 struct interface *
     55 if_ifwithaddr(addr)
     56 	struct sockaddr *addr;
     57 {
     58 	register struct interface *ifp;
     59 
     60 #define	same(a1, a2) \
     61 	(memcmp((a1)->sa_data, (a2)->sa_data, 14) == 0)
     62 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
     63 		if (ifp->int_flags & IFF_REMOTE)
     64 			continue;
     65 		if (ifp->int_addr.sa_family != addr->sa_family)
     66 			continue;
     67 		if (same(&ifp->int_addr, addr))
     68 			break;
     69 		if ((ifp->int_flags & IFF_BROADCAST) &&
     70 		    same(&ifp->int_broadaddr, addr))
     71 			break;
     72 	}
     73 	return (ifp);
     74 }
     75 
     76 /*
     77  * Find the point-to-point interface with destination address addr.
     78  */
     79 struct interface *
     80 if_ifwithdstaddr(addr)
     81 	struct sockaddr *addr;
     82 {
     83 	register struct interface *ifp;
     84 
     85 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
     86 		if ((ifp->int_flags & IFF_POINTOPOINT) == 0)
     87 			continue;
     88 		if (same(&ifp->int_dstaddr, addr))
     89 			break;
     90 	}
     91 	return (ifp);
     92 }
     93 
     94 /*
     95  * Find the interface on the network
     96  * of the specified address.
     97  */
     98 struct interface *
     99 if_ifwithnet(addr)
    100 	register struct sockaddr *addr;
    101 {
    102 	register struct interface *ifp;
    103 	register int af = addr->sa_family;
    104 	register int (*netmatch)();
    105 
    106 	if (af >= af_max)
    107 		return (0);
    108 	netmatch = afswitch[af].af_netmatch;
    109 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    110 		if (ifp->int_flags & IFF_REMOTE)
    111 			continue;
    112 		if (af != ifp->int_addr.sa_family)
    113 			continue;
    114 		if ((*netmatch)(addr, &ifp->int_addr))
    115 			break;
    116 	}
    117 	return (ifp);
    118 }
    119 
    120 /*
    121  * Find an interface from which the specified address
    122  * should have come from.  Used for figuring out which
    123  * interface a packet came in on -- for tracing.
    124  */
    125 struct interface *
    126 if_iflookup(addr)
    127 	struct sockaddr *addr;
    128 {
    129 	register struct interface *ifp, *maybe;
    130 	register int af = addr->sa_family;
    131 	register int (*netmatch)();
    132 
    133 	if (af >= af_max)
    134 		return (0);
    135 	maybe = 0;
    136 	netmatch = afswitch[af].af_netmatch;
    137 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    138 		if (ifp->int_addr.sa_family != af)
    139 			continue;
    140 		if (same(&ifp->int_addr, addr))
    141 			break;
    142 		if ((ifp->int_flags & IFF_BROADCAST) &&
    143 		    same(&ifp->int_broadaddr, addr))
    144 			break;
    145 		if ((ifp->int_flags & IFF_POINTOPOINT) &&
    146 		    same(&ifp->int_dstaddr, addr))
    147 			break;
    148 		if (maybe == 0 && (*netmatch)(addr, &ifp->int_addr))
    149 			maybe = ifp;
    150 	}
    151 	if (ifp == 0)
    152 		ifp = maybe;
    153 	return (ifp);
    154 }
    155