route.c

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//==========================================================================
//
//      src/sys/net/route.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * Copyright (c) 1980, 1986, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)route.c	8.2 (Berkeley) 11/15/93
 * $FreeBSD: src/sys/net/route.c,v 1.59.2.3 2001/07/29 19:18:02 ume Exp $
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/domain.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/ip_mroute.h>

#include <sys/sockio.h>  // for eCos routing protocols

#define	SA(p) ((struct sockaddr *)(p))

struct route_cb route_cb;
static struct rtstat rtstat;
struct radix_node_head *rt_tables[AF_MAX+1];

static int	rttrash;		/* routes not in table but not freed */

static void rt_maskedcopy __P((struct sockaddr *,
	    struct sockaddr *, struct sockaddr *));
static void rtable_init __P((void **));

static void
rtable_init(table)
	void **table;
{
	struct domain *dom;
	for (dom = domains; dom; dom = dom->dom_next)
		if (dom->dom_rtattach)
			dom->dom_rtattach(&table[dom->dom_family],
			    dom->dom_rtoffset);
}

static void call_route_init( void * arg )
{
    route_init();
}

void
route_init()
{
	rn_init();	/* initialize all zeroes, all ones, mask table */
	rtable_init((void **)rt_tables);
}

// FIXME: This function is only here because BOOTP fails on a second interface.
//        This failure is due to the fact that a route to 0.0.0.0 seems to be
//        incredibly sticky, i.e. can't be deleted.  BOOTP uses this to
//        achieve a generic broadcast.  Sadly it seems that BOOTP servers will
//        only work this way, thus the hack.
//
//        This version enumerates all IPv4 routes and deletes them - this leaks less
//        store than the previous version.

static int
rt_reinit_rtdelete( struct radix_node *rn, void *vifp )
{
    struct rtentry *rt = (struct rtentry *)rn;
    if (rt->rt_ifa->ifa_addr->sa_family == AF_INET) {
      rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt),
		0, NULL);
    }
    return (0);
}

void
cyg_route_reinit(void)
{
    int i;
    for (i = 0;  i < AF_MAX+1;  i++) {
        struct radix_node_head *rnh;
        rnh = rt_tables[i];
        if (rnh) {
            (*rnh->rnh_walktree)(rnh, rt_reinit_rtdelete, NULL);
        }
    }
}

/*
 * Packet routing routines.
 */
void
rtalloc(ro)
	register struct route *ro;
{
	rtalloc_ign(ro, 0UL);
}

void
rtalloc_ign(ro, ignore)
	register struct route *ro;
	u_long ignore;
{
	struct rtentry *rt;
	int s;

	if ((rt = ro->ro_rt) != NULL) {
		if (rt->rt_ifp != NULL && rt->rt_flags & RTF_UP)
			return;
		/* XXX - We are probably always at splnet here already. */
		s = splnet();
		RTFREE(rt);
		ro->ro_rt = NULL;
		splx(s);
	}
	ro->ro_rt = rtalloc1(&ro->ro_dst, 1, ignore);
}

/*
 * Look up the route that matches the address given
 * Or, at least try.. Create a cloned route if needed.
 */
struct rtentry *
rtalloc1(dst, report, ignflags)
	register struct sockaddr *dst;
	int report;
	u_long ignflags;
{
	register struct radix_node_head *rnh = rt_tables[dst->sa_family];
	register struct rtentry *rt;
	register struct radix_node *rn;
	struct rtentry *newrt = 0;
	struct rt_addrinfo info;
	u_long nflags;
	int  s = splnet(), err = 0, msgtype = RTM_MISS;

	/*
	 * Look up the address in the table for that Address Family
	 */
	if (rnh && (rn = rnh->rnh_matchaddr((caddr_t)dst, rnh)) &&
	    ((rn->rn_flags & RNF_ROOT) == 0)) {
		/*
		 * If we find it and it's not the root node, then
		 * get a refernce on the rtentry associated.
		 */
		newrt = rt = (struct rtentry *)rn;
		nflags = rt->rt_flags & ~ignflags;
		if (report && (nflags & (RTF_CLONING | RTF_PRCLONING))) {
			/*
			 * We are apparently adding (report = 0 in delete).
			 * If it requires that it be cloned, do so.
			 * (This implies it wasn't a HOST route.)
			 */
			err = rtrequest(RTM_RESOLVE, dst, SA(0),
					      SA(0), 0, &newrt);
			if (err) {
				/*
				 * If the cloning didn't succeed, maybe
				 * what we have will do. Return that.
				 */
				newrt = rt;
				rt->rt_refcnt++;
				goto miss;
			}
			if ((rt = newrt) && (rt->rt_flags & RTF_XRESOLVE)) {
				/*
				 * If the new route specifies it be
				 * externally resolved, then go do that.
				 */
				msgtype = RTM_RESOLVE;
				goto miss;
			}
		} else
			rt->rt_refcnt++;
	} else {
		/*
		 * Either we hit the root or couldn't find any match,
		 * Which basically means
		 * "caint get there frm here"
		 */
		rtstat.rts_unreach++;
	miss:	if (report) {
			/*
			 * If required, report the failure to the supervising
			 * Authorities.
			 * For a delete, this is not an error. (report == 0)
			 */
			bzero((caddr_t)&info, sizeof(info));
			info.rti_info[RTAX_DST] = dst;
			rt_missmsg(msgtype, &info, 0, err);
		}
	}
	splx(s);
	return (newrt);
}

/*
 * Remove a reference count from an rtentry.
 * If the count gets low enough, take it out of the routing table
 */
void
rtfree(rt)
	register struct rtentry *rt;
{
	/*
	 * find the tree for that address family
	 */
	register struct radix_node_head *rnh =
		rt_tables[rt_key(rt)->sa_family];
	register struct ifaddr *ifa;

	if (rt == 0 || rnh == 0)
		panic("rtfree");

	/*
	 * decrement the reference count by one and if it reaches 0,
	 * and there is a close function defined, call the close function
	 */
	rt->rt_refcnt--;
	if(rnh->rnh_close && rt->rt_refcnt == 0) {
		rnh->rnh_close((struct radix_node *)rt, rnh);
	}

	/*
	 * If we are no longer "up" (and ref == 0)
	 * then we can free the resources associated
	 * with the route.
	 */
	if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0) {
		if (rt->rt_nodes->rn_flags & (RNF_ACTIVE | RNF_ROOT))
			panic ("rtfree 2");
		/*
		 * the rtentry must have been removed from the routing table
		 * so it is represented in rttrash.. remove that now.
		 */
		rttrash--;

#ifdef	DIAGNOSTIC
		if (rt->rt_refcnt < 0) {
			printf("rtfree: %p not freed (neg refs)\n", rt);
			return;
		}
#endif

		/*
		 * release references on items we hold them on..
		 * e.g other routes and ifaddrs.
		 */
		if((ifa = rt->rt_ifa))
			IFAFREE(ifa);
		if (rt->rt_parent) {
			RTFREE(rt->rt_parent);
		}

		/*
		 * The key is separatly alloc'd so free it (see rt_setgate()).
		 * This also frees the gateway, as they are always malloc'd
		 * together.
		 */
		Free(rt_key(rt));

		/*
		 * and the rtentry itself of course
		 */
		Free(rt);
	}
}

void
ifafree(ifa)
	register struct ifaddr *ifa;
{
	if (ifa == NULL)
		panic("ifafree");
	if (ifa->ifa_refcnt == 0)
		free(ifa, M_IFADDR);
	else
		ifa->ifa_refcnt--;
}

/*
 * Force a routing table entry to the specified
 * destination to go through the given gateway.
 * Normally called as a result of a routing redirect
 * message from the network layer.
 *
 * N.B.: must be called at splnet
 *
 */
void
rtredirect(dst, gateway, netmask, flags, src, rtp)
	struct sockaddr *dst, *gateway, *netmask, *src;
	int flags;
	struct rtentry **rtp;
{
	register struct rtentry *rt;
	int error = 0;
	short *stat = 0;
	struct rt_addrinfo info;
	struct ifaddr *ifa;

	/* verify the gateway is directly reachable */
	if ((ifa = ifa_ifwithnet(gateway)) == 0) {
		error = ENETUNREACH;
		goto out;
	}
	rt = rtalloc1(dst, 0, 0UL);
	/*
	 * If the redirect isn't from our current router for this dst,
	 * it's either old or wrong.  If it redirects us to ourselves,
	 * we have a routing loop, perhaps as a result of an interface
	 * going down recently.
	 */
#define	equal(a1, a2) \
	((a1)->sa_len == (a2)->sa_len && \
	 bcmp((caddr_t)(a1), (caddr_t)(a2), (a1)->sa_len) == 0)
	if (!(flags & RTF_DONE) && rt &&
	     (!equal(src, rt->rt_gateway) || rt->rt_ifa != ifa))
		error = EINVAL;
	else if (ifa_ifwithaddr(gateway))
		error = EHOSTUNREACH;
	if (error)
		goto done;
	/*
	 * Create a new entry if we just got back a wildcard entry
	 * or the the lookup failed.  This is necessary for hosts
	 * which use routing redirects generated by smart gateways
	 * to dynamically build the routing tables.
	 */
	if ((rt == 0) || (rt_mask(rt) && rt_mask(rt)->sa_len < 2))
		goto create;
	/*
	 * Don't listen to the redirect if it's
	 * for a route to an interface.
	 */
	if (rt->rt_flags & RTF_GATEWAY) {
		if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
			/*
			 * Changing from route to net => route to host.
			 * Create new route, rather than smashing route to net.
			 */
		create:
			flags |=  RTF_GATEWAY | RTF_DYNAMIC;
			error = rtrequest((int)RTM_ADD, dst, gateway,
				    netmask, flags,
				    (struct rtentry **)0);