usr/src/sys/net/route.c

/*
 * Copyright (c) 1980, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *      @(#)route.c     7.7 (Berkeley) %G%
 */

#include "param.h"
#include "systm.h"
#include "mbuf.h"
#include "protosw.h"
#include "socket.h"
#include "dir.h"
#include "user.h"
#include "ioctl.h"
#include "errno.h"

#include "if.h"
#include "af.h"
#include "route.h"
#include "radix.h"

#include "radix.c"
#ifdef INET
#include "../netinet/in.h"
#include "../netinet/in_var.h"
#endif

int     rttrash;                /* routes not in table but not freed */
struct  sockaddr wildcard;      /* zero valued cookie for wildcard searches */
int     rthashsize = RTHASHSIZ; /* for netstat, etc. */

static int rtinits_done = 0;
struct radix_node_head *ns_rnhead, *in_rnhead;
rtinitheads()
{
        if (rtinits_done == 0 &&
            rn_inithead(&ns_rnhead, 16, AF_NS) &&
            rn_inithead(&in_rnhead, 32, AF_INET))
                rtinits_done = 1;
}

/*
 * Packet routing routines.
 */
rtalloc(ro)
        register struct route *ro;
{
        register struct radix_node_head *rnh;
        register struct radix_node *rn;
        register struct rtentry *rt = 0;
        u_char af = ro->ro_dst.sa_family;
        int  s;

        if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
                return;                          /* XXX */
        s = splnet();
        for (rnh = radix_node_head; rnh && (af != rnh->rnh_af); )
                rnh = rnh->rnh_next;
        if (rnh && rnh->rnh_treetop &&
            (rn = rn_match((char *)&(ro->ro_dst), rnh->rnh_treetop)) &&
            ((rn->rn_flags & RNF_ROOT) == 0)) {
                rt = &(((struct nrtentry *)rn)->nrt_rt);
                rt->rt_refcnt++;
        } else
                rtstat.rts_unreach++;
        ro->ro_rt = rt;
        splx(s);
}

rtfree(rt)
        register struct rtentry *rt;
{
        register struct nrtentry *nrt;
        u_char *af;
        if (rt == 0)
                panic("rtfree");
        rt->rt_refcnt--;
        if (rt->rt_refcnt <= 0 && (rt->rt_flags&RTF_UP) == 0) {
                rttrash--;
                nrt = (struct nrtentry *) (((struct radix_node *)rt) - 2);
                if (nrt->nrt_nodes->rn_flags & (RNF_ACTIVE | RNF_ROOT))
                        panic ("rtfree 2");
                free((caddr_t)nrt, M_RTABLE);
        }
}

/*
 * 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
 *
 */
rtredirect(dst, gateway, flags, src)
        struct sockaddr *dst, *gateway, *src;
        int flags;
{
        struct route ro;
        register struct rtentry *rt;

        /* verify the gateway is directly reachable */
        if (ifa_ifwithnet(gateway) == 0) {
                rtstat.rts_badredirect++;
                return;
        }
        ro.ro_dst = *dst;
        ro.ro_rt = 0;
        rtalloc(&ro);
        rt = ro.ro_rt;
#define equal(a1, a2) \
  (bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
        /*
         * 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.
         */
        if ((rt && !equal(src, &rt->rt_gateway)) || ifa_ifwithaddr(gateway)) {
                rtstat.rts_badredirect++;
                if (rt)
                        rtfree(rt);
                return;
        }
        /*
         * Old comment:
         * 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.
         *
         * New comment:
         * If we survived the previous tests, it doesn't matter
         * what sort of entry we got when we looked it up;
         * we should just go ahead and free the reference to
         * the route we created.  rtalloc will not give a
         * pointer to the root node.  And if we got a pointer
         * to a default gateway, we should free the reference
         * in any case.
        if (rt) {
                rtfree(rt);
                rt = 0;
        }
         */
        if (rt == 0) {
                rtinit(dst, gateway, (int)SIOCADDRT,
                    (flags & RTF_HOST) | RTF_GATEWAY | RTF_DYNAMIC);
                rtstat.rts_dynamic++;
                return;
        }
        /*
         * 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.
                         */
                        rtinit(dst, gateway, (int)SIOCADDRT,
                            flags | RTF_DYNAMIC);
                        rtstat.rts_dynamic++;
                } else {
                        /*
                         * Smash the current notion of the gateway to
                         * this destination.
                         */
                        rt->rt_gateway = *gateway; /*XXX -- size? */
                        rt->rt_flags |= RTF_MODIFIED;
                        rtstat.rts_newgateway++;
                }
        } else
                rtstat.rts_badredirect++;
        rtfree(rt);
}

/*
 * Routing table ioctl interface.
 */
rtioctl(cmd, data)
        int cmd;
        caddr_t data;
{

        if (cmd != SIOCADDRT && cmd != SIOCDELRT)
                return (EINVAL);
        if (!suser())
                return (u.u_error);
        return (rtrequest(cmd, (struct rtentry *)data));
}
/*
 * This routine will go away soon.
 * Tries to guess which netmask is appropriate for a given net.
 */
static struct sockaddr_in rtgmask = { 8, 0 };

char *
rtgetmask(sa, ifa)
register struct sockaddr *sa;
register struct ifaddr *ifa;
{
        u_long i, net, mask, subnet;

        switch (sa->sa_family) {
#ifdef INET
        register struct in_ifaddr *ia;

        case AF_INET:

                i = ntohl(((struct sockaddr_in *)sa)->sin_addr.s_addr);
                if (i == 0) {
                        rtgmask.sin_addr.s_addr = 0;
                        return ((char *)&rtgmask);
                } else if (IN_CLASSA(i)) {
                        net = i & IN_CLASSA_NET;
                        mask = IN_CLASSA_NET;
                } else if (IN_CLASSB(i)) {
                        net = i & IN_CLASSB_NET;
                        mask = IN_CLASSB_NET;
                } else if (IN_CLASSC(i)) {
                        net = i & IN_CLASSC_NET;
                        mask = IN_CLASSC_NET;
                } else {
                        net = i;
                        mask = 0xffffffff;
                }

                /*
                 * Check whether network is a subnet;
                 * if so, return subnet number.
                 */
                for (ia = in_ifaddr; ia; ia = ia->ia_next)
                        if (net == ia->ia_net) {
                                ifa = &ia->ia_ifa;
                                break;
                        }
                if (ia == 0) {
                        rtgmask.sin_addr.s_addr = ntohl(mask);
                        return ((char *)&rtgmask);
                }
#endif
        }
        return ((char *)ifa->ifa_netmask);
}

/*
 * Carry out a request to change the routing table.  Called by
 * interfaces at boot time to make their ``local routes'' known,
 * for ioctl's, and as the result of routing redirects.
 */
rtrequest(req, entry)
        int req;
        register struct rtentry *entry;
{
        register struct rtentry *rt;
        int s, error = 0, found;
        u_char af;
        struct ifaddr *ifa;
        struct ifaddr *ifa_ifwithdstaddr();
        register struct nrtentry *nrt;
        register struct radix_node *rn;
        register struct radix_node_head *rnh;
        struct radix_node *head;
        char *netmask;

#ifdef COMPAT_43
#if BYTE_ORDER != BIG_ENDIAN
        s = splnet();
        if (entry->rt_dst.sa_family == 0 && entry->rt_dst.sa_len < 16) {
                entry->rt_dst.sa_family = entry->rt_dst.sa_len;
                entry->rt_dst.sa_len = 16;
        }
        if (entry->rt_gateway.sa_family == 0 && entry->rt_gateway.sa_len < 16) {
                entry->rt_gateway.sa_family = entry->rt_gateway.sa_len;
                entry->rt_gateway.sa_len = 16;
        }
#else
        if (entry->rt_dst.sa_len == 0)
                entry->rt_dst.sa_len = 16;
        if (entry->rt_gateway.sa_len == 0)
                entry->rt_gateway.sa_len = 16;
#endif
#endif
        if (rtinits_done == 0)
                rtinitheads();
        af = entry->rt_dst.sa_family;
        for (rnh = radix_node_head; rnh && (af != rnh->rnh_af); )
                rnh = rnh->rnh_next;
        if (rnh == 0) {
                error = ESRCH;
                goto bad;
        }
        head = rnh->rnh_treetop;
        if ((entry->rt_flags & RTF_GATEWAY) == 0) {
                /*
                 * If we are adding a route to an interface,
                 * and the interface is a pt to pt link
                 * we should search for the destination
                 * as our clue to the interface.  Otherwise
                 * we can use the local address.
                 */
                ifa = 0;
                if (entry->rt_flags & RTF_HOST)
                        ifa = ifa_ifwithdstaddr(&entry->rt_dst);
                if (ifa == 0)
                        ifa = ifa_ifwithaddr(&entry->rt_gateway);
        } else {
                /*
                 * If we are adding a route to a remote net
                 * or host, the gateway may still be on the
                 * other end of a pt to pt link.
                 */
                ifa = ifa_ifwithdstaddr(&entry->rt_gateway);
        }
        if (ifa == 0) {
                ifa = ifa_ifwithnet(&entry->rt_gateway);
                if (ifa == 0 && req == SIOCADDRT) {
                        error = ENETUNREACH;
                        goto bad;
                }
        }
        if (entry->rt_flags & RTF_HOST)
                netmask = 0;
        else
                netmask = rtgetmask(&entry->rt_dst, ifa);
        switch (req) {

        case SIOCDELRT:
                if ((rn = rn_delete((char *)&entry->rt_dst,
                                        netmask, head)) == 0) {
                        error = ESRCH;
                        goto bad;
                }
                if (rn->rn_flags & (RNF_ACTIVE | RNF_ROOT))
                        panic ("rtrequest delete");
                nrt = (struct nrtentry *)rn;
                nrt->nrt_rt.rt_flags &= ~RTF_UP;
                if (nrt->nrt_rt.rt_refcnt > 0)
                        rttrash++;
                else
                        free((caddr_t)nrt, M_RTABLE);
                break;

        case SIOCADDRT:
                Malloc(nrt, struct nrtentry *, sizeof *nrt);
                if (nrt == 0) {
                        error = ENOBUFS;
                        goto bad;
                }
                Bzero(nrt, sizeof *nrt);
                rn = rn_addroute((char *)&entry->rt_dst, netmask,
                                                    head, nrt->nrt_nodes);
                if (rn == 0) {
                        free((caddr_t)nrt, M_RTABLE);
                        error = EEXIST;
                        goto bad;
                }
                rt = &nrt->nrt_rt;
                rn->rn_key = (char *)&(nrt->nrt_rt.rt_dst);
                rt->rt_dst = entry->rt_dst;
                rt->rt_gateway = entry->rt_gateway;
                rt->rt_flags = RTF_UP |
                    (entry->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_DYNAMIC));
                rt->rt_use = 0;
                rt->rt_refcnt = 0;
                rt->rt_ifp = ifa->ifa_ifp;
                break;
        }
bad:
        splx(s);
        return (error);
}

/*
 * Set up a routing table entry, normally
 * for an interface.
 */
rtinit(dst, gateway, cmd, flags)
        struct sockaddr *dst, *gateway;
        int cmd, flags;
{
        struct rtentry route;

        bzero((caddr_t)&route, sizeof (route));
        route.rt_dst = *dst;
        route.rt_gateway = *gateway;
        route.rt_flags = flags;
        (void) rtrequest(cmd, &route);
}