source: rtems-libbsd/freebsd/sys/net/if_arcsubr.c @ 6d9d7b1

#include <machine/rtems-bsd-kernel-space.h>

/*      $NetBSD: if_arcsubr.c,v 1.36 2001/06/14 05:44:23 itojun Exp $   */
/*      $FreeBSD$ */

/*-
 * Copyright (c) 1994, 1995 Ignatios Souvatzis
 * Copyright (c) 1982, 1989, 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.
 *
 * from: NetBSD: if_ethersubr.c,v 1.9 1994/06/29 06:36:11 cgd Exp
 *       @(#)if_ethersubr.c     8.1 (Berkeley) 6/10/93
 *
 */
#include <rtems/bsd/local/opt_inet.h>
#include <rtems/bsd/local/opt_inet6.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/syslog.h>

#include <machine/cpu.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_arc.h>
#include <net/if_arp.h>
#include <net/bpf.h>
#include <net/if_llatbl.h>

#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#endif

#ifdef INET6
#include <netinet6/nd6.h>
#endif

#define ARCNET_ALLOW_BROKEN_ARP

static struct mbuf *arc_defrag(struct ifnet *, struct mbuf *);
static int arc_resolvemulti(struct ifnet *, struct sockaddr **,
                            struct sockaddr *);

u_int8_t  arcbroadcastaddr = 0;

#define ARC_LLADDR(ifp) (*(u_int8_t *)IF_LLADDR(ifp))

#define senderr(e) { error = (e); goto bad;}
#define SIN(s)  ((const struct sockaddr_in *)(s))

/*
 * ARCnet output routine.
 * Encapsulate a packet of type family for the local net.
 * Assumes that ifp is actually pointer to arccom structure.
 */
int
arc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
    struct route *ro)
{
        struct arc_header       *ah;
        int                     error;
        u_int8_t                atype, adst;
        int                     loop_copy = 0;
        int                     isphds;
#if defined(INET) || defined(INET6)
        int                     is_gw = 0;
#endif

        if (!((ifp->if_flags & IFF_UP) &&
            (ifp->if_drv_flags & IFF_DRV_RUNNING)))
                return(ENETDOWN); /* m, m1 aren't initialized yet */

        error = 0;
#if defined(INET) || defined(INET6)
        if (ro != NULL)
                is_gw = (ro->ro_flags & RT_HAS_GW) != 0;
#endif

        switch (dst->sa_family) {
#ifdef INET
        case AF_INET:

                /*
                 * For now, use the simple IP addr -> ARCnet addr mapping
                 */
                if (m->m_flags & (M_BCAST|M_MCAST))
                        adst = arcbroadcastaddr; /* ARCnet broadcast address */
                else if (ifp->if_flags & IFF_NOARP)
                        adst = ntohl(SIN(dst)->sin_addr.s_addr) & 0xFF;
                else {
                        error = arpresolve(ifp, is_gw, m, dst, &adst, NULL,
                            NULL);
                        if (error)
                                return (error == EWOULDBLOCK ? 0 : error);
                }

                atype = (ifp->if_flags & IFF_LINK0) ?
                        ARCTYPE_IP_OLD : ARCTYPE_IP;
                break;
        case AF_ARP:
        {
                struct arphdr *ah;
                ah = mtod(m, struct arphdr *);
                ah->ar_hrd = htons(ARPHRD_ARCNET);

                loop_copy = -1; /* if this is for us, don't do it */

                switch(ntohs(ah->ar_op)) {
                case ARPOP_REVREQUEST:
                case ARPOP_REVREPLY:
                        atype = ARCTYPE_REVARP;
                        break;
                case ARPOP_REQUEST:
                case ARPOP_REPLY:
                default:
                        atype = ARCTYPE_ARP;
                        break;
                }

                if (m->m_flags & M_BCAST)
                        bcopy(ifp->if_broadcastaddr, &adst, ARC_ADDR_LEN);
                else
                        bcopy(ar_tha(ah), &adst, ARC_ADDR_LEN);
        
        }
        break;
#endif
#ifdef INET6
        case AF_INET6:
                if ((m->m_flags & M_MCAST) != 0)
                        adst = arcbroadcastaddr; /* ARCnet broadcast address */
                else {
                        error = nd6_resolve(ifp, is_gw, m, dst, &adst, NULL,
                            NULL);
                        if (error != 0)
                                return (error == EWOULDBLOCK ? 0 : error);
                }
                atype = ARCTYPE_INET6;
                break;
#endif
        case AF_UNSPEC:
            {
                const struct arc_header *ah;

                loop_copy = -1;
                ah = (const struct arc_header *)dst->sa_data;
                adst = ah->arc_dhost;
                atype = ah->arc_type;

                if (atype == ARCTYPE_ARP) {
                        atype = (ifp->if_flags & IFF_LINK0) ?
                            ARCTYPE_ARP_OLD: ARCTYPE_ARP;

#ifdef ARCNET_ALLOW_BROKEN_ARP
                        /*
                         * XXX It's not clear per RFC826 if this is needed, but
                         * "assigned numbers" say this is wrong.
                         * However, e.g., AmiTCP 3.0Beta used it... we make this
                         * switchable for emergency cases. Not perfect, but...
                         */
                        if (ifp->if_flags & IFF_LINK2)
                                mtod(m, struct arphdr *)->ar_pro = atype - 1;
#endif
                }
                break;
            }
        default:
                if_printf(ifp, "can't handle af%d\n", dst->sa_family);
                senderr(EAFNOSUPPORT);
        }

        isphds = arc_isphds(atype);
        M_PREPEND(m, isphds ? ARC_HDRNEWLEN : ARC_HDRLEN, M_NOWAIT);
        if (m == NULL)
                senderr(ENOBUFS);
        ah = mtod(m, struct arc_header *);
        ah->arc_type = atype;
        ah->arc_dhost = adst;
        ah->arc_shost = ARC_LLADDR(ifp);
        if (isphds) {
                ah->arc_flag = 0;
                ah->arc_seqid = 0;
        }

        if ((ifp->if_flags & IFF_SIMPLEX) && (loop_copy != -1)) {
                if ((m->m_flags & M_BCAST) || (loop_copy > 0)) {
                        struct mbuf *n = m_copym(m, 0, M_COPYALL, M_NOWAIT);

                        (void) if_simloop(ifp, n, dst->sa_family, ARC_HDRLEN);
                } else if (ah->arc_dhost == ah->arc_shost) {
                        (void) if_simloop(ifp, m, dst->sa_family, ARC_HDRLEN);
                        return (0);     /* XXX */
                }
        }

        BPF_MTAP(ifp, m);

        error = ifp->if_transmit(ifp, m);

        return (error);

bad:
        if (m)
                m_freem(m);
        return (error);
}

void
arc_frag_init(struct ifnet *ifp)
{
        struct arccom *ac;

        ac = (struct arccom *)ifp->if_l2com;
        ac->curr_frag = 0;
}

struct mbuf *
arc_frag_next(struct ifnet *ifp)
{
        struct arccom *ac;
        struct mbuf *m;
        struct arc_header *ah;

        ac = (struct arccom *)ifp->if_l2com;
        if ((m = ac->curr_frag) == NULL) {
                int tfrags;

                /* dequeue new packet */
                IF_DEQUEUE(&ifp->if_snd, m);
                if (m == NULL)
                        return 0;

                ah = mtod(m, struct arc_header *);
                if (!arc_isphds(ah->arc_type))
                        return m;

                ++ac->ac_seqid;         /* make the seqid unique */
                tfrags = howmany(m->m_pkthdr.len, ARC_MAX_DATA);
                ac->fsflag = 2 * tfrags - 3;
                ac->sflag = 0;
                ac->rsflag = ac->fsflag;
                ac->arc_dhost = ah->arc_dhost;
                ac->arc_shost = ah->arc_shost;
                ac->arc_type = ah->arc_type;

                m_adj(m, ARC_HDRNEWLEN);
                ac->curr_frag = m;
        }

        /* split out next fragment and return it */
        if (ac->sflag < ac->fsflag) {
                /* we CAN'T have short packets here */
                ac->curr_frag = m_split(m, ARC_MAX_DATA, M_NOWAIT);
                if (ac->curr_frag == 0) {
                        m_freem(m);
                        return 0;
                }

                M_PREPEND(m, ARC_HDRNEWLEN, M_NOWAIT);
                if (m == NULL) {
                        m_freem(ac->curr_frag);
                        ac->curr_frag = 0;
                        return 0;
                }

                ah = mtod(m, struct arc_header *);
                ah->arc_flag = ac->rsflag;
                ah->arc_seqid = ac->ac_seqid;

                ac->sflag += 2;
                ac->rsflag = ac->sflag;
        } else if ((m->m_pkthdr.len >=
            ARC_MIN_FORBID_LEN - ARC_HDRNEWLEN + 2) &&
            (m->m_pkthdr.len <=
            ARC_MAX_FORBID_LEN - ARC_HDRNEWLEN + 2)) {
                ac->curr_frag = 0;

                M_PREPEND(m, ARC_HDRNEWLEN_EXC, M_NOWAIT);
                if (m == NULL)
                        return 0;

                ah = mtod(m, struct arc_header *);
                ah->arc_flag = 0xFF;
                ah->arc_seqid = 0xFFFF;
                ah->arc_type2 = ac->arc_type;
                ah->arc_flag2 = ac->sflag;
                ah->arc_seqid2 = ac->ac_seqid;
        } else {
                ac->curr_frag = 0;

                M_PREPEND(m, ARC_HDRNEWLEN, M_NOWAIT);
                if (m == NULL)
                        return 0;

                ah = mtod(m, struct arc_header *);
                ah->arc_flag = ac->sflag;
                ah->arc_seqid = ac->ac_seqid;
        }

        ah->arc_dhost = ac->arc_dhost;
        ah->arc_shost = ac->arc_shost;
        ah->arc_type = ac->arc_type;

        return m;
}

/*
 * Defragmenter. Returns mbuf if last packet found, else
 * NULL. frees incoming mbuf as necessary.
 */

static __inline struct mbuf *
arc_defrag(struct ifnet *ifp, struct mbuf *m)
{
        struct arc_header *ah, *ah1;
        struct arccom *ac;
        struct ac_frag *af;
        struct mbuf *m1;
        char *s;
        int newflen;
        u_char src,dst,typ;

        ac = (struct arccom *)ifp->if_l2com;

        if (m->m_len < ARC_HDRNEWLEN) {
                m = m_pullup(m, ARC_HDRNEWLEN);
                if (m == NULL) {
                        if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                        return NULL;
                }
        }

        ah = mtod(m, struct arc_header *);
        typ = ah->arc_type;

        if (!arc_isphds(typ))
                return m;

        src = ah->arc_shost;
        dst = ah->arc_dhost;

        if (ah->arc_flag == 0xff) {
                m_adj(m, 4);

                if (m->m_len < ARC_HDRNEWLEN) {
                        m = m_pullup(m, ARC_HDRNEWLEN);
                        if (m == NULL) {
                                if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
                                return NULL;
                        }
                }

                ah = mtod(m, struct arc_header *);
        }

        af = &ac->ac_fragtab[src];
        m1 = af->af_packet;
        s = "debug code error";

        if (ah->arc_flag & 1) {
                /*
                 * first fragment. We always initialize, which is
                 * about the right thing to do, as we only want to
                 * accept one fragmented packet per src at a time.
                 */
                if (m1 != NULL)
                        m_freem(m1);

                af->af_packet = m;
                m1 = m;
                af->af_maxflag = ah->arc_flag;
                af->af_lastseen = 0;
                af->af_seqid = ah->arc_seqid;

                return NULL;
                /* notreached */
        } else {
                /* check for unfragmented packet */
                if (ah->arc_flag == 0)
                        return m;

                /* do we have a first packet from that src? */
                if (m1 == NULL) {
                        s = "no first frag";
                        goto outofseq;
                }

                ah1 = mtod(m1, struct arc_header *);

                if (ah->arc_seqid != ah1->arc_seqid) {
                        s = "seqid differs";
                        goto outofseq;
                }

                if (typ != ah1->arc_type) {
                        s = "type differs";
                        goto outofseq;
                }

                if (dst != ah1->arc_dhost) {
                        s = "dest host differs";
                        goto outofseq;
                }

                /* typ, seqid and dst are ok here. */

                if (ah->arc_flag == af->af_lastseen) {
                        m_freem(m);
                        return NULL;
                }

                if (ah->arc_flag == af->af_lastseen + 2) {
                        /* ok, this is next fragment */
                        af->af_lastseen = ah->arc_flag;
                        m_adj(m,ARC_HDRNEWLEN);

                        /*
                         * m_cat might free the first mbuf (with pkthdr)
                         * in 2nd chain; therefore:
                         */

                        newflen = m->m_pkthdr.len;

                        m_cat(m1,m);

                        m1->m_pkthdr.len += newflen;

                        /* is it the last one? */
                        if (af->af_lastseen > af->af_maxflag) {
                                af->af_packet = NULL;
                                return(m1);
                        } else
                                return NULL;
                }
                s = "other reason";
                /* if all else fails, it is out of sequence, too */
        }
outofseq:
        if (m1) {
                m_freem(m1);
                af->af_packet = NULL;
        }

        if (m)
                m_freem(m);

        log(LOG_INFO,"%s: got out of seq. packet: %s\n",
            ifp->if_xname, s);

        return NULL;
}

/*
 * return 1 if Packet Header Definition Standard, else 0.
 * For now: old IP, old ARP aren't obviously. Lacking correct information,
 * we guess that besides new IP and new ARP also IPX and APPLETALK are PHDS.
 * (Apple and Novell corporations were involved, among others, in PHDS work).
 * Easiest is to assume that everybody else uses that, too.
 */
int
arc_isphds(u_int8_t type)
{
        return (type != ARCTYPE_IP_OLD &&
                type != ARCTYPE_ARP_OLD &&
                type != ARCTYPE_DIAGNOSE);
}

/*
 * Process a received Arcnet packet;
 * the packet is in the mbuf chain m with
 * the ARCnet header.
 */
void
arc_input(struct ifnet *ifp, struct mbuf *m)
{
        struct arc_header *ah;
        int isr;
        u_int8_t atype;

        if ((ifp->if_flags & IFF_UP) == 0) {
                m_freem(m);
                return;
        }

        /* possibly defragment: */
        m = arc_defrag(ifp, m);
        if (m == NULL)
                return;

        BPF_MTAP(ifp, m);

        ah = mtod(m, struct arc_header *);
        /* does this belong to us? */
        if ((ifp->if_flags & IFF_PROMISC) == 0
            && ah->arc_dhost != arcbroadcastaddr
            && ah->arc_dhost != ARC_LLADDR(ifp)) {
                m_freem(m);
                return;
        }

        if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);

        if (ah->arc_dhost == arcbroadcastaddr) {
                m->m_flags |= M_BCAST|M_MCAST;
                if_inc_counter(ifp, IFCOUNTER_IMCASTS, 1);
        }

        atype = ah->arc_type;
        switch (atype) {
#ifdef INET
        case ARCTYPE_IP:
                m_adj(m, ARC_HDRNEWLEN);
                isr = NETISR_IP;
                break;

        case ARCTYPE_IP_OLD:
                m_adj(m, ARC_HDRLEN);
                isr = NETISR_IP;
                break;

        case ARCTYPE_ARP:
                if (ifp->if_flags & IFF_NOARP) {
                        /* Discard packet if ARP is disabled on interface */
                        m_freem(m);
                        return;
                }
                m_adj(m, ARC_HDRNEWLEN);
                isr = NETISR_ARP;
#ifdef ARCNET_ALLOW_BROKEN_ARP
                mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
#endif
                break;

        case ARCTYPE_ARP_OLD:
                if (ifp->if_flags & IFF_NOARP) {
                        /* Discard packet if ARP is disabled on interface */
                        m_freem(m);
                        return;
                }
                m_adj(m, ARC_HDRLEN);
                isr = NETISR_ARP;
#ifdef ARCNET_ALLOW_BROKEN_ARP
                mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
#endif
                break;
#endif
#ifdef INET6
        case ARCTYPE_INET6:
                m_adj(m, ARC_HDRNEWLEN);
                isr = NETISR_IPV6;
                break;
#endif
        default:
                m_freem(m);
                return;
        }
        M_SETFIB(m, ifp->if_fib);
        netisr_dispatch(isr, m);
}

/*
 * Register (new) link level address.
 */
void
arc_storelladdr(struct ifnet *ifp, u_int8_t lla)
{
        ARC_LLADDR(ifp) = lla;
}

/*
 * Perform common duties while attaching to interface list
 */
void
arc_ifattach(struct ifnet *ifp, u_int8_t lla)
{
        struct ifaddr *ifa;
        struct sockaddr_dl *sdl;
        struct arccom *ac;

        if_attach(ifp);
        ifp->if_addrlen = 1;
        ifp->if_hdrlen = ARC_HDRLEN;
        ifp->if_mtu = 1500;
        ifp->if_resolvemulti = arc_resolvemulti;
        if (ifp->if_baudrate == 0)
                ifp->if_baudrate = 2500000;
        ifa = ifp->if_addr;
        KASSERT(ifa != NULL, ("%s: no lladdr!\n", __func__));
        sdl = (struct sockaddr_dl *)ifa->ifa_addr;
        sdl->sdl_type = IFT_ARCNET;
        sdl->sdl_alen = ifp->if_addrlen;

        if (ifp->if_flags & IFF_BROADCAST)
                ifp->if_flags |= IFF_MULTICAST|IFF_ALLMULTI;

        ac = (struct arccom *)ifp->if_l2com;
        ac->ac_seqid = (time_second) & 0xFFFF; /* try to make seqid unique */
        if (lla == 0) {
                /* XXX this message isn't entirely clear, to me -- cgd */
                log(LOG_ERR,"%s: link address 0 reserved for broadcasts.  Please change it and ifconfig %s down up\n",
                   ifp->if_xname, ifp->if_xname);
        }
        arc_storelladdr(ifp, lla);

        ifp->if_broadcastaddr = &arcbroadcastaddr;

        bpfattach(ifp, DLT_ARCNET, ARC_HDRLEN);
}

void
arc_ifdetach(struct ifnet *ifp)
{
        bpfdetach(ifp);
        if_detach(ifp);
}

int
arc_ioctl(struct ifnet *ifp, u_long command, caddr_t data)
{
        struct ifaddr *ifa = (struct ifaddr *) data;
        struct ifreq *ifr = (struct ifreq *) data;
        int error = 0;

        switch (command) {
        case SIOCSIFADDR:
                ifp->if_flags |= IFF_UP;
                switch (ifa->ifa_addr->sa_family) {
#ifdef INET
                case AF_INET:
                        ifp->if_init(ifp->if_softc);    /* before arpwhohas */
                        arp_ifinit(ifp, ifa);
                        break;
#endif
                default:
                        ifp->if_init(ifp->if_softc);
                        break;
                }
                break;

        case SIOCGIFADDR:
                {
                        struct sockaddr *sa;

                        sa = (struct sockaddr *) &ifr->ifr_data;
                        *(u_int8_t *)sa->sa_data = ARC_LLADDR(ifp);
                }
                break;

        case SIOCADDMULTI:
        case SIOCDELMULTI:
                if (ifr == NULL)
                        error = EAFNOSUPPORT;
                else {
                        switch (ifr->ifr_addr.sa_family) {
                        case AF_INET:
                        case AF_INET6:
                                error = 0;
                                break;
                        default:
                                error = EAFNOSUPPORT;
                                break;
                        }
                }
                break;

        case SIOCSIFMTU:
                /*
                 * Set the interface MTU.
                 * mtu can't be larger than ARCMTU for RFC1051
                 * and can't be larger than ARC_PHDS_MTU
                 */
                if (((ifp->if_flags & IFF_LINK0) && ifr->ifr_mtu > ARCMTU) ||
                    ifr->ifr_mtu > ARC_PHDS_MAXMTU)
                        error = EINVAL;
                else
                        ifp->if_mtu = ifr->ifr_mtu;
                break;
        }

        return (error);
}

/* based on ether_resolvemulti() */
int
arc_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
    struct sockaddr *sa)
{
        struct sockaddr_dl *sdl;
#ifdef INET
        struct sockaddr_in *sin;
#endif
#ifdef INET6
        struct sockaddr_in6 *sin6;
#endif

        switch(sa->sa_family) {
        case AF_LINK:
                /*
                * No mapping needed. Just check that it's a valid MC address.
                */
                sdl = (struct sockaddr_dl *)sa;
                if (*LLADDR(sdl) != arcbroadcastaddr)
                        return EADDRNOTAVAIL;
                *llsa = NULL;
                return 0;
#ifdef INET
        case AF_INET:
                sin = (struct sockaddr_in *)sa;
                if (!IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
                        return EADDRNOTAVAIL;
                sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
                sdl->sdl_alen = ARC_ADDR_LEN;
                *LLADDR(sdl) = 0;
                *llsa = (struct sockaddr *)sdl;
                return 0;
#endif
#ifdef INET6
        case AF_INET6:
                sin6 = (struct sockaddr_in6 *)sa;
                if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
                        /*
                         * An IP6 address of 0 means listen to all
                         * of the Ethernet multicast address used for IP6.
                         * (This is used for multicast routers.)
                         */
                        ifp->if_flags |= IFF_ALLMULTI;
                        *llsa = NULL;
                        return 0;
                }
                if (!IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
                        return EADDRNOTAVAIL;
                sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
                sdl->sdl_alen = ARC_ADDR_LEN;
                *LLADDR(sdl) = 0;
                *llsa = (struct sockaddr *)sdl;
                return 0;
#endif

        default:
                /*
                 * Well, the text isn't quite right, but it's the name
                 * that counts...
                 */
                return EAFNOSUPPORT;
        }
}

static MALLOC_DEFINE(M_ARCCOM, "arccom", "ARCNET interface internals");

static void*
arc_alloc(u_char type, struct ifnet *ifp)
{
        struct arccom   *ac;
        
        ac = malloc(sizeof(struct arccom), M_ARCCOM, M_WAITOK | M_ZERO);
        ac->ac_ifp = ifp;

        return (ac);
}

static void
arc_free(void *com, u_char type)
{

        free(com, M_ARCCOM);
}

static int
arc_modevent(module_t mod, int type, void *data)
{

        switch (type) {
        case MOD_LOAD:
                if_register_com_alloc(IFT_ARCNET, arc_alloc, arc_free);
                break;
        case MOD_UNLOAD:
                if_deregister_com_alloc(IFT_ARCNET);
                break;
        default:
                return EOPNOTSUPP;
        }

        return (0);
}

static moduledata_t arc_mod = {
        "arcnet",
        arc_modevent,
        0
};

DECLARE_MODULE(arcnet, arc_mod, SI_SUB_INIT_IF, SI_ORDER_ANY);
MODULE_VERSION(arcnet, 1);