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if.c revision 1.1 
      1 /*
      2  * Copyright (c) 1983 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 static char sccsid[] = "@(#)if.c	5.6 (Berkeley) 6/1/90";
     36 #endif /* not lint */
     37 
     38 /*
     39  * Routing Table Management Daemon
     40  */
     41 #include "defs.h"
     42 
     43 extern	struct interface *ifnet;
     44 
     45 /*
     46  * Find the interface with address addr.
     47  */
     48 struct interface *
     49 if_ifwithaddr(addr)
     50 	struct sockaddr *addr;
     51 {
     52 	register struct interface *ifp;
     53 
     54 #define	same(a1, a2) \
     55 	(bcmp((caddr_t)((a1)->sa_data), (caddr_t)((a2)->sa_data), 14) == 0)
     56 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
     57 		if (ifp->int_flags & IFF_REMOTE)
     58 			continue;
     59 		if (ifp->int_addr.sa_family != addr->sa_family)
     60 			continue;
     61 		if (same(&ifp->int_addr, addr))
     62 			break;
     63 		if ((ifp->int_flags & IFF_BROADCAST) &&
     64 		    same(&ifp->int_broadaddr, addr))
     65 			break;
     66 	}
     67 	return (ifp);
     68 }
     69 
     70 /*
     71  * Find the point-to-point interface with destination address addr.
     72  */
     73 struct interface *
     74 if_ifwithdstaddr(addr)
     75 	struct sockaddr *addr;
     76 {
     77 	register struct interface *ifp;
     78 
     79 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
     80 		if ((ifp->int_flags & IFF_POINTOPOINT) == 0)
     81 			continue;
     82 		if (same(&ifp->int_dstaddr, addr))
     83 			break;
     84 	}
     85 	return (ifp);
     86 }
     87 
     88 /*
     89  * Find the interface on the network
     90  * of the specified address.
     91  */
     92 struct interface *
     93 if_ifwithnet(addr)
     94 	register struct sockaddr *addr;
     95 {
     96 	register struct interface *ifp;
     97 	register int af = addr->sa_family;
     98 	register int (*netmatch)();
     99 
    100 	if (af >= af_max)
    101 		return (0);
    102 	netmatch = afswitch[af].af_netmatch;
    103 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    104 		if (ifp->int_flags & IFF_REMOTE)
    105 			continue;
    106 		if (af != ifp->int_addr.sa_family)
    107 			continue;
    108 		if ((*netmatch)(addr, &ifp->int_addr))
    109 			break;
    110 	}
    111 	return (ifp);
    112 }
    113 
    114 /*
    115  * Find an interface from which the specified address
    116  * should have come from.  Used for figuring out which
    117  * interface a packet came in on -- for tracing.
    118  */
    119 struct interface *
    120 if_iflookup(addr)
    121 	struct sockaddr *addr;
    122 {
    123 	register struct interface *ifp, *maybe;
    124 	register int af = addr->sa_family;
    125 	register int (*netmatch)();
    126 
    127 	if (af >= af_max)
    128 		return (0);
    129 	maybe = 0;
    130 	netmatch = afswitch[af].af_netmatch;
    131 	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
    132 		if (ifp->int_addr.sa_family != af)
    133 			continue;
    134 		if (same(&ifp->int_addr, addr))
    135 			break;
    136 		if ((ifp->int_flags & IFF_BROADCAST) &&
    137 		    same(&ifp->int_broadaddr, addr))
    138 			break;
    139 		if ((ifp->int_flags & IFF_POINTOPOINT) &&
    140 		    same(&ifp->int_dstaddr, addr))
    141 			break;
    142 		if (maybe == 0 && (*netmatch)(addr, &ifp->int_addr))
    143 			maybe = ifp;
    144 	}
    145 	if (ifp == 0)
    146 		ifp = maybe;
    147 	return (ifp);
    148 }
    149