xref: /csrg-svn/sbin/routed/if.c (revision 27231)

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)if.c	5.3 (Berkeley) 04/20/86";
#endif not lint

/*
 * Routing Table Management Daemon
 */
#include "defs.h"

extern	struct interface *ifnet;

/*
 * Find the interface with address addr.
 */
struct interface *
if_ifwithaddr(addr)
	struct sockaddr *addr;
{
	register struct interface *ifp;

#define	same(a1, a2) \
	(bcmp((caddr_t)((a1)->sa_data), (caddr_t)((a2)->sa_data), 14) == 0)
	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
		if (ifp->int_flags & IFF_REMOTE)
			continue;
		if (ifp->int_addr.sa_family != addr->sa_family)
			continue;
		if (same(&ifp->int_addr, addr))
			break;
		if ((ifp->int_flags & IFF_BROADCAST) &&
		    same(&ifp->int_broadaddr, addr))
			break;
	}
	return (ifp);
}

/*
 * Find the point-to-point interface with destination address addr.
 */
struct interface *
if_ifwithdstaddr(addr)
	struct sockaddr *addr;
{
	register struct interface *ifp;

	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
		if ((ifp->int_flags & IFF_POINTOPOINT) == 0)
			continue;
		if (same(&ifp->int_dstaddr, addr))
			break;
	}
	return (ifp);
}

/*
 * Find the interface on the network
 * of the specified address.
 */
struct interface *
if_ifwithnet(addr)
	register struct sockaddr *addr;
{
	register struct interface *ifp;
	register int af = addr->sa_family;
	register int (*netmatch)();

	if (af >= af_max)
		return (0);
	netmatch = afswitch[af].af_netmatch;
	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
		if (ifp->int_flags & IFF_REMOTE)
			continue;
		if (af != ifp->int_addr.sa_family)
			continue;
		if ((*netmatch)(addr, &ifp->int_addr))
			break;
	}
	return (ifp);
}

/*
 * Find an interface from which the specified address
 * should have come from.  Used for figuring out which
 * interface a packet came in on -- for tracing.
 */
struct interface *
if_iflookup(addr)
	struct sockaddr *addr;
{
	register struct interface *ifp, *maybe;
	register int af = addr->sa_family;
	register int (*netmatch)();

	if (af >= af_max)
		return (0);
	maybe = 0;
	netmatch = afswitch[af].af_netmatch;
	for (ifp = ifnet; ifp; ifp = ifp->int_next) {
		if (ifp->int_addr.sa_family != af)
			continue;
		if (same(&ifp->int_addr, addr))
			break;
		if ((ifp->int_flags & IFF_BROADCAST) &&
		    same(&ifp->int_broadaddr, addr))
			break;
		if ((ifp->int_flags & IFF_POINTOPOINT) &&
		    same(&ifp->int_dstaddr, addr))
			break;
		if (maybe == 0 && (*netmatch)(addr, &ifp->int_addr))
			maybe = ifp;
	}
	if (ifp == 0)
		ifp = maybe;
	return (ifp);
}