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//==========================================================================

//

//      sys/net/rtsock.c

//

//     

//

//==========================================================================

// ####BSDALTCOPYRIGHTBEGIN####                                             

// -------------------------------------------                              

// Portions of this software may have been derived from OpenBSD             

// or other sources, and if so are covered by the appropriate copyright     

// and license included herein.                                             

// -------------------------------------------                              

// ####BSDALTCOPYRIGHTEND####                                               

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    gthomas

// Contributors: gthomas

// Date:         2000-01-10

// Purpose:      

// Description:  

//              

//

//####DESCRIPTIONEND####

//

//==========================================================================

/*      $OpenBSD: rtsock.c,v 1.8 1999/12/08 06:50:18 itojun Exp $       */

/*      $NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $  */

/*

 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.

 * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.

 */

/*

 * Copyright (c) 1988, 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.

 *

 *      @(#)rtsock.c    8.6 (Berkeley) 2/11/95

 */

#include <sys/param.h>

#ifndef __ECOS

#include <sys/systm.h>

#include <sys/proc.h>

#endif

#include <sys/mbuf.h>

#include <sys/socket.h>

#include <sys/socketvar.h>

#include <sys/domain.h>

#include <sys/protosw.h>

#ifndef __ECOS

#include <vm/vm.h>

#include <sys/sysctl.h>

#endif

#include <net/if.h>

#include <net/route.h>

#include <net/raw_cb.h>

#include <machine/stdarg.h>

struct  sockaddr route_dst = { 2, PF_ROUTE, };

struct  sockaddr route_src = { 2, PF_ROUTE, };

struct  sockproto route_proto = { PF_ROUTE, };

struct walkarg {

        int     w_op, w_arg, w_given, w_needed, w_tmemsize;

        caddr_t w_where, w_tmem;

};

static struct mbuf *

                rt_msg1 __P((int, struct rt_addrinfo *));

static int      rt_msg2 __P((int,

                    struct rt_addrinfo *, caddr_t, struct walkarg *));

static void     rt_xaddrs __P((caddr_t, caddr_t, struct rt_addrinfo *));

static void rt_setif __P((struct rtentry *, struct sockaddr *,

        struct sockaddr *, struct sockaddr *));

/* Sleazy use of local variables throughout file, warning!!!! */

#define dst     info.rti_info[RTAX_DST]

#define gate    info.rti_info[RTAX_GATEWAY]

#define netmask info.rti_info[RTAX_NETMASK]

#define genmask info.rti_info[RTAX_GENMASK]

#define ifpaddr info.rti_info[RTAX_IFP]

#define ifaaddr info.rti_info[RTAX_IFA]

#define brdaddr info.rti_info[RTAX_BRD]

/*ARGSUSED*/

int

route_usrreq(so, req, m, nam, control)

        register struct socket *so;

        int req;

        struct mbuf *m, *nam, *control;

{

        register int error = 0;

        register struct rawcb *rp = sotorawcb(so);

        int s;

        if (req == PRU_ATTACH) {

                MALLOC(rp, struct rawcb *, sizeof(*rp), M_PCB, M_WAITOK);

                if ((so->so_pcb = rp) != NULL)

                        bzero(so->so_pcb, sizeof(*rp));

        }

        if (req == PRU_DETACH && rp) {

                int af = rp->rcb_proto.sp_protocol;

                if (af == AF_INET)

                        route_cb.ip_count--;

                else if (af == AF_INET6)

                        route_cb.ip6_count--;

                else if (af == AF_NS)

                        route_cb.ns_count--;

                else if (af == AF_ISO)

                        route_cb.iso_count--;

                route_cb.any_count--;

        }

        s = splsoftnet();

        /*

         * Don't call raw_usrreq() in the attach case, because

         * we want to allow non-privileged processes to listen on

         * and send "safe" commands to the routing socket.

         */

        if (req == PRU_ATTACH) {

#ifndef __ECOS

                if (curproc == 0)

                        error = EACCES;

                else

#endif // FIXME?

                        error = raw_attach(so, (int)(long)nam);

        } else

                error = raw_usrreq(so, req, m, nam, control);

        rp = sotorawcb(so);

        if (req == PRU_ATTACH && rp) {

                int af = rp->rcb_proto.sp_protocol;

                if (error) {

                        free((caddr_t)rp, M_PCB);

                        splx(s);

                        return (error);

                }

                if (af == AF_INET)

                        route_cb.ip_count++;

                else if (af == AF_INET6)

                        route_cb.ip6_count++;

                else if (af == AF_NS)

                        route_cb.ns_count++;

                else if (af == AF_ISO)

                        route_cb.iso_count++;

                rp->rcb_faddr = &route_src;

                route_cb.any_count++;

                soisconnected(so);

                so->so_options |= SO_USELOOPBACK;

        }

        splx(s);

        return (error);

}

/*ARGSUSED*/

int

#if __STDC__

route_output(struct mbuf *m, ...)

#else

route_output(m, va_alist)

        struct mbuf *m;

        va_dcl

#endif

{

        register struct rt_msghdr *rtm = 0;

        register struct rtentry *rt = 0;

        struct rtentry *saved_nrt = 0;

        struct radix_node_head *rnh;

        struct rt_addrinfo info;

        int len, error = 0;

        struct ifnet *ifp = 0;

        struct socket *so;

        va_list ap;

        va_start(ap, m);

        so = va_arg(ap, struct socket *);

        va_end(ap);

        bzero(&info, sizeof(info));

#define senderr(e) { error = e; goto flush;}

        if (m == 0 || ((m->m_len < sizeof(int32_t)) &&

                       (m = m_pullup(m, sizeof(int32_t))) == 0))

                return (ENOBUFS);

        if ((m->m_flags & M_PKTHDR) == 0)

                panic("route_output");

        len = m->m_pkthdr.len;

        if (len < sizeof(*rtm) ||

            len != mtod(m, struct rt_msghdr *)->rtm_msglen) {

                dst = 0;

                senderr(EINVAL);

        }

        R_Malloc(rtm, struct rt_msghdr *, len);

        if (rtm == 0) {

                dst = 0;

                senderr(ENOBUFS);

        }

        m_copydata(m, 0, len, (caddr_t)rtm);

        if (rtm->rtm_version != RTM_VERSION) {

                dst = 0;

                senderr(EPROTONOSUPPORT);

        }

#ifdef __ECOS

        rtm->rtm_pid = 0; // FIXME

#else

        rtm->rtm_pid = curproc->p_pid;

#endif

        info.rti_addrs = rtm->rtm_addrs;

        rt_xaddrs((caddr_t)(rtm + 1), len + (caddr_t)rtm, &info);

        if (dst == 0)

                senderr(EINVAL);

        if (genmask) {

                struct radix_node *t;

                t = rn_addmask((caddr_t)genmask, 0, 1);

                if (t && Bcmp(genmask, t->rn_key, *(u_char *)genmask) == 0)

                        genmask = (struct sockaddr *)(t->rn_key);

                else

                        senderr(ENOBUFS);

        }

        /*

         * Verify that the caller has the appropriate privilege; RTM_GET

         * is the only operation the non-superuser is allowed.

         */

#ifndef __ECOS

        if (rtm->rtm_type != RTM_GET &&

            suser(curproc->p_ucred, &curproc->p_acflag) != 0)

                senderr(EACCES);

#endif

        switch (rtm->rtm_type) {

        case RTM_ADD:

                if (gate == 0)

                        senderr(EINVAL);

                error = rtrequest(RTM_ADD, dst, gate, netmask,

                                        rtm->rtm_flags, &saved_nrt);

                if (error == 0 && saved_nrt) {

                        /*

                         * If the route request specified an interface with

                         * IFA and/or IFP, we set the requested interface on

                         * the route with rt_setif.  It would be much better

                         * to do this inside rtrequest, but that would

                         * require passing the desired interface, in some

                         * form, to rtrequest.  Since rtrequest is called in

                         * so many places (roughly 40 in our source), adding

                         * a parameter is to much for us to swallow; this is

                         * something for the FreeBSD developers to tackle.

                         * Instead, we let rtrequest compute whatever

                         * interface it wants, then come in behind it and

                         * stick in the interface that we really want.  This

                         * works reasonably well except when rtrequest can't

                         * figure out what interface to use (with

                         * ifa_withroute) and returns ENETUNREACH.  Ideally

                         * it shouldn't matter if rtrequest can't figure out

                         * the interface if we're going to explicitly set it

                         * ourselves anyway.  But practically we can't

                         * recover here because rtrequest will not do any of

                         * the work necessary to add the route if it can't

                         * find an interface.  As long as there is a default

                         * route that leads to some interface, rtrequest will

                         * find an interface, so this problem should be

                         * rarely encountered.

                         * dwiggins@bbn.com

                         */

                        rt_setif(saved_nrt, ifpaddr, ifaaddr, gate);

                        rt_setmetrics(rtm->rtm_inits,

                                &rtm->rtm_rmx, &saved_nrt->rt_rmx);

                        saved_nrt->rt_refcnt--;

                        saved_nrt->rt_genmask = genmask;

                }

                break;

        case RTM_DELETE:

                error = rtrequest(RTM_DELETE, dst, gate, netmask,

                                rtm->rtm_flags, &saved_nrt);

                if (error == 0) {

                        (rt = saved_nrt)->rt_refcnt++;

                        goto report;

                }

                break;

        case RTM_GET:

        case RTM_CHANGE:

        case RTM_LOCK:

                if ((rnh = rt_tables[dst->sa_family]) == 0) {

                        senderr(EAFNOSUPPORT);

                } else if ((rt = (struct rtentry *)

                                rnh->rnh_lookup(dst, netmask, rnh)) != NULL)

                        rt->rt_refcnt++;

                else

                        senderr(ESRCH);

                switch(rtm->rtm_type) {

                case RTM_GET:

                report:

                        dst = rt_key(rt);

                        gate = rt->rt_gateway;

                        netmask = rt_mask(rt);

                        genmask = rt->rt_genmask;

                        if (rtm->rtm_addrs & (RTA_IFP | RTA_IFA)) {

                                if ((ifp = rt->rt_ifp) != NULL) {

                                        ifpaddr = ifp->if_addrlist.tqh_first->ifa_addr;

                                        ifaaddr = rt->rt_ifa->ifa_addr;

                                        if (ifp->if_flags & IFF_POINTOPOINT)

                                                brdaddr = rt->rt_ifa->ifa_dstaddr;

                                        else

                                                brdaddr = 0;

                                        rtm->rtm_index = ifp->if_index;

                                } else {

                                        ifpaddr = 0;

                                        ifaaddr = 0;

                            }

                        }

                        len = rt_msg2(rtm->rtm_type, &info, (caddr_t)0,

                                (struct walkarg *)0);

                        if (len > rtm->rtm_msglen) {

                                struct rt_msghdr *new_rtm;

                                R_Malloc(new_rtm, struct rt_msghdr *, len);

                                if (new_rtm == 0)

                                        senderr(ENOBUFS);

                                Bcopy(rtm, new_rtm, rtm->rtm_msglen);

                                Free(rtm); rtm = new_rtm;

                        }

                        (void)rt_msg2(rtm->rtm_type, &info, (caddr_t)rtm,

                                (struct walkarg *)0);

                        rtm->rtm_flags = rt->rt_flags;

                        rtm->rtm_rmx = rt->rt_rmx;

                        rtm->rtm_addrs = info.rti_addrs;

                        break;

                case RTM_CHANGE:

                        if (gate && rt_setgate(rt, rt_key(rt), gate))

#ifdef __ECOS

                                senderr(EMFILE);

#else

                                senderr(EDQUOT);

#endif

#if 1

                        rt_setif(rt, ifpaddr, ifaaddr, gate);

#else

                        /* new gateway could require new ifaddr, ifp;

                           flags may also be different; ifp may be specified

                           by ll sockaddr when protocol address is ambiguous */

                        if (ifpaddr && (ifa = ifa_ifwithnet(ifpaddr)) &&

                            (ifp = ifa->ifa_ifp) && (ifaaddr || gate))

                                ifa = ifaof_ifpforaddr(ifaaddr ? ifaaddr : gate,

                                                        ifp);

                        else if ((ifaaddr && (ifa = ifa_ifwithaddr(ifaaddr))) ||

                                 (gate && (ifa = ifa_ifwithroute(rt->rt_flags,

                                                        rt_key(rt), gate))))

                                ifp = ifa->ifa_ifp;

                        if (ifa) {

                                register struct ifaddr *oifa = rt->rt_ifa;

                                if (oifa != ifa) {

                                    if (oifa && oifa->ifa_rtrequest)

                                        oifa->ifa_rtrequest(RTM_DELETE,

                                                                rt, gate);

                                    IFAFREE(rt->rt_ifa);

                                    rt->rt_ifa = ifa;

                                    ifa->ifa_refcnt++;

                                    rt->rt_ifp = ifp;

                                }

                        }

#endif

                        rt_setmetrics(rtm->rtm_inits, &rtm->rtm_rmx,

                                        &rt->rt_rmx);

#if 0

                        if (rt->rt_ifa && rt->rt_ifa->ifa_rtrequest)

                               rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, gate);

#endif

                        if (genmask)

                                rt->rt_genmask = genmask;

                        /*

                         * Fall into

                         */

                case RTM_LOCK:

                        rt->rt_rmx.rmx_locks &= ~(rtm->rtm_inits);

                        rt->rt_rmx.rmx_locks |=

                                (rtm->rtm_inits & rtm->rtm_rmx.rmx_locks);

                        break;

                }

                break;

        default:

                senderr(EOPNOTSUPP);

        }

flush:

        if (rtm) {

                if (error)

                        rtm->rtm_errno = error;

                else

                        rtm->rtm_flags |= RTF_DONE;

        }

        if (rt)

                rtfree(rt);

    {

        register struct rawcb *rp = 0;

        /*

         * Check to see if we don't want our own messages.

         */

        if ((so->so_options & SO_USELOOPBACK) == 0) {

                if (route_cb.any_count <= 1) {

                        if (rtm)

                                Free(rtm);

                        m_freem(m);

                        return (error);

                }

                /* There is another listener, so construct message */

                rp = sotorawcb(so);

        }

        if (rtm) {

                m_copyback(m, 0, rtm->rtm_msglen, (caddr_t)rtm);

                Free(rtm);

        }

        if (rp)

                rp->rcb_proto.sp_family = 0; /* Avoid us */

        if (dst)

                route_proto.sp_protocol = dst->sa_family;

        raw_input(m, &route_proto, &route_src, &route_dst);

        if (rp)

                rp->rcb_proto.sp_family = PF_ROUTE;

    }

        return (error);

}

void

rt_setmetrics(which, in, out)

        u_long which;

        register struct rt_metrics *in, *out;

{

#define metric(f, e) if (which & (f)) out->e = in->e;

        metric(RTV_RPIPE, rmx_recvpipe);

        metric(RTV_SPIPE, rmx_sendpipe);

        metric(RTV_SSTHRESH, rmx_ssthresh);

        metric(RTV_RTT, rmx_rtt);

        metric(RTV_RTTVAR, rmx_rttvar);

        metric(RTV_HOPCOUNT, rmx_hopcount);

        metric(RTV_MTU, rmx_mtu);

        metric(RTV_EXPIRE, rmx_expire);

#undef metric

}

/*

 * Set route's interface given ifpaddr, ifaaddr, and gateway.

 */

static void

rt_setif(rt, Ifpaddr, Ifaaddr, Gate)

        struct rtentry *rt;

        struct sockaddr *Ifpaddr, *Ifaaddr, *Gate;

{

        struct ifaddr *ifa = 0;

        struct ifnet  *ifp = 0;

        /* new gateway could require new ifaddr, ifp;

           flags may also be different; ifp may be specified

           by ll sockaddr when protocol address is ambiguous */

        if (Ifpaddr && (ifa = ifa_ifwithnet(Ifpaddr)) &&

            (ifp = ifa->ifa_ifp) && (Ifaaddr || Gate))

                ifa = ifaof_ifpforaddr(Ifaaddr ? Ifaaddr : Gate,

                                        ifp);

        else if (Ifpaddr && (ifp = if_withname(Ifpaddr)) ) {

                ifa = Gate ? ifaof_ifpforaddr(Gate, ifp) :

                                TAILQ_FIRST(&ifp->if_addrlist);

        }

        else if ((Ifaaddr && (ifa = ifa_ifwithaddr(Ifaaddr))) ||

                 (Gate && (ifa = ifa_ifwithroute(rt->rt_flags,

                                        rt_key(rt), Gate))))

                ifp = ifa->ifa_ifp;

        if (ifa) {

                register struct ifaddr *oifa = rt->rt_ifa;

                if (oifa != ifa) {

                    if (oifa && oifa->ifa_rtrequest)

                        oifa->ifa_rtrequest(RTM_DELETE,

                                                rt, Gate);

                    IFAFREE(rt->rt_ifa);

                    rt->rt_ifa = ifa;

                    ifa->ifa_refcnt++;

                    rt->rt_ifp = ifp;

                    rt->rt_rmx.rmx_mtu = ifp->if_mtu;

                    if (rt->rt_ifa && rt->rt_ifa->ifa_rtrequest)

                        rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, Gate);

                } else

                        goto call_ifareq;

                return;

        }

      call_ifareq:

        /* XXX: to reset gateway to correct value, at RTM_CHANGE */

        if (rt->rt_ifa && rt->rt_ifa->ifa_rtrequest)

                rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, Gate);

}

#define ROUNDUP(a) \

        ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))

#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))

static void

rt_xaddrs(cp, cplim, rtinfo)

        register caddr_t cp, cplim;

        register struct rt_addrinfo *rtinfo;

{

        register struct sockaddr *sa;

        register int i;

        bzero(rtinfo->rti_info, sizeof(rtinfo->rti_info));

        for (i = 0; (i < RTAX_MAX) && (cp < cplim); i++) {

                if ((rtinfo->rti_addrs & (1 << i)) == 0)

                        continue;

                rtinfo->rti_info[i] = sa = (struct sockaddr *)cp;

                ADVANCE(cp, sa);

        }

}

/*

 * Copy data from a buffer back into the indicated mbuf chain,

 * starting "off" bytes from the beginning, extending the mbuf

 * chain if necessary. The mbuf needs to be properly initalized

 * including the setting of m_len.

 */

void

m_copyback(m0, off, len, cp)

        struct  mbuf *m0;

        register int off;

        register int len;

        caddr_t cp;

{

        register int mlen;

        register struct mbuf *m = m0, *n;

        int totlen = 0;

        if (m0 == 0)

                return;

        while (off > (mlen = m->m_len)) {

                off -= mlen;

                totlen += mlen;

                if (m->m_next == 0) {

                        n = m_getclr(M_DONTWAIT, m->m_type);

                        if (n == 0)

                                goto out;

                        n->m_len = min(MLEN, len + off);

                        m->m_next = n;

                }

                m = m->m_next;

        }

        while (len > 0) {

                mlen = min (m->m_len - off, len);

                bcopy(cp, off + mtod(m, caddr_t), (unsigned)mlen);

                cp += mlen;

                len -= mlen;

                mlen += off;

                off = 0;

                totlen += mlen;

                if (len == 0)

                        break;

                if (m->m_next == 0) {

                        n = m_get(M_DONTWAIT, m->m_type);

                        if (n == 0)

                                break;

                        n->m_len = min(MLEN, len);

                        m->m_next = n;

                }

                m = m->m_next;

        }

out:    if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))

                m->m_pkthdr.len = totlen;

}

static struct mbuf *

rt_msg1(type, rtinfo)

        int type;

        register struct rt_addrinfo *rtinfo;

{

        register struct rt_msghdr *rtm;

        register struct mbuf *m;

        register int i;

        register struct sockaddr *sa;

        int len, dlen;

        m = m_gethdr(M_DONTWAIT, MT_DATA);

        if (m == 0)

                return (m);

        switch (type) {

        case RTM_DELADDR:

        case RTM_NEWADDR:

                len = sizeof(struct ifa_msghdr);

                break;

        case RTM_IFINFO:

                len = sizeof(struct if_msghdr);

                break;

        default:

                len = sizeof(struct rt_msghdr);

        }

        if (len > MHLEN)

                panic("rt_msg1");

        m->m_pkthdr.len = m->m_len = len;

        m->m_pkthdr.rcvif = 0;

        rtm = mtod(m, struct rt_msghdr *);

        bzero((caddr_t)rtm, len);