/*-
 * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>

#include <net/bpf.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/vnet.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>

#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>

#define MEMTU                   (1500 - sizeof(struct mobhdr))
static const char mename[] = "me";
static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
/* Minimal forwarding header RFC 2004 */
struct mobhdr {
        uint8_t         mob_proto;      /* protocol */
        uint8_t         mob_flags;      /* flags */
#define MOB_FLAGS_SP    0x80            /* source present */
        uint16_t        mob_csum;       /* header checksum */
        struct in_addr  mob_dst;        /* original destination address */
        struct in_addr  mob_src;        /* original source addr (optional) */
} __packed;

struct me_softc {
        struct ifnet            *me_ifp;
        u_int                   me_fibnum;
        struct in_addr          me_src;
        struct in_addr          me_dst;

        CK_LIST_ENTRY(me_softc) chain;
        CK_LIST_ENTRY(me_softc) srchash;
};
CK_LIST_HEAD(me_list, me_softc);
#define ME2IFP(sc)              ((sc)->me_ifp)
#define ME_READY(sc)            ((sc)->me_src.s_addr != 0)
#define ME_RLOCK_TRACKER        struct epoch_tracker me_et
#define ME_RLOCK()              epoch_enter_preempt(net_epoch_preempt, &me_et)
#define ME_RUNLOCK()            epoch_exit_preempt(net_epoch_preempt, &me_et)
#define ME_WAIT()               epoch_wait_preempt(net_epoch_preempt)

#ifndef ME_HASH_SIZE
#define ME_HASH_SIZE    (1 << 4)
#endif
VNET_DEFINE_STATIC(struct me_list *, me_hashtbl) = NULL;
VNET_DEFINE_STATIC(struct me_list *, me_srchashtbl) = NULL;
#define V_me_hashtbl            VNET(me_hashtbl)
#define V_me_srchashtbl         VNET(me_srchashtbl)
#define ME_HASH(src, dst)       (V_me_hashtbl[\
    me_hashval((src), (dst)) & (ME_HASH_SIZE - 1)])
#define ME_SRCHASH(src)         (V_me_srchashtbl[\
    fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (ME_HASH_SIZE - 1)])

static struct sx me_ioctl_sx;
SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");

static int      me_clone_create(struct if_clone *, int, caddr_t);
static void     me_clone_destroy(struct ifnet *);
VNET_DEFINE_STATIC(struct if_clone *, me_cloner);
#define V_me_cloner     VNET(me_cloner)

#ifdef VIMAGE
static void     me_reassign(struct ifnet *, struct vnet *, char *);
#endif
static void     me_qflush(struct ifnet *);
static int      me_transmit(struct ifnet *, struct mbuf *);
static int      me_ioctl(struct ifnet *, u_long, caddr_t);
static int      me_output(struct ifnet *, struct mbuf *,
                    const struct sockaddr *, struct route *);
static int      me_input(struct mbuf *, int, int, void *);

static int      me_set_tunnel(struct me_softc *, in_addr_t, in_addr_t);
static void     me_delete_tunnel(struct me_softc *);

SYSCTL_DECL(_net_link);
static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Minimal Encapsulation for IP (RFC 2004)");
#ifndef MAX_ME_NEST
#define MAX_ME_NEST 1
#endif

VNET_DEFINE_STATIC(int, max_me_nesting) = MAX_ME_NEST;
#define V_max_me_nesting        VNET(max_me_nesting)
SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
    &VNET_NAME(max_me_nesting), 0, "Max nested tunnels");

static uint32_t
me_hashval(in_addr_t src, in_addr_t dst)
{
        uint32_t ret;

        ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
        return (fnv_32_buf(&dst, sizeof(dst), ret));
}

static struct me_list *
me_hashinit(void)
{
        struct me_list *hash;
        int i;

        hash = malloc(sizeof(struct me_list) * ME_HASH_SIZE,
            M_IFME, M_WAITOK);
        for (i = 0; i < ME_HASH_SIZE; i++)
                CK_LIST_INIT(&hash[i]);

        return (hash);
}

static void
vnet_me_init(const void *unused __unused)
{

        V_me_cloner = if_clone_simple(mename, me_clone_create,
            me_clone_destroy, 0);
}
VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
    vnet_me_init, NULL);

static void
vnet_me_uninit(const void *unused __unused)
{

        if (V_me_hashtbl != NULL) {
                free(V_me_hashtbl, M_IFME);
                V_me_hashtbl = NULL;
                ME_WAIT();
                free(V_me_srchashtbl, M_IFME);
        }
        if_clone_detach(V_me_cloner);
}
VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
    vnet_me_uninit, NULL);

static int
me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
        struct me_softc *sc;

        sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
        sc->me_fibnum = curthread->td_proc->p_fibnum;
        ME2IFP(sc) = if_alloc(IFT_TUNNEL);
        ME2IFP(sc)->if_softc = sc;
        if_initname(ME2IFP(sc), mename, unit);

        ME2IFP(sc)->if_mtu = MEMTU;
        ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
        ME2IFP(sc)->if_output = me_output;
        ME2IFP(sc)->if_ioctl = me_ioctl;
        ME2IFP(sc)->if_transmit = me_transmit;
        ME2IFP(sc)->if_qflush = me_qflush;
#ifdef VIMAGE
        ME2IFP(sc)->if_reassign = me_reassign;
#endif
        ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
        ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
        if_attach(ME2IFP(sc));
        bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
        return (0);
}

#ifdef VIMAGE
static void
me_reassign(struct ifnet *ifp, struct vnet *new_vnet __unused,
    char *unused __unused)
{
        struct me_softc *sc;

        sx_xlock(&me_ioctl_sx);
        sc = ifp->if_softc;
        if (sc != NULL)
                me_delete_tunnel(sc);
        sx_xunlock(&me_ioctl_sx);
}
#endif /* VIMAGE */

static void
me_clone_destroy(struct ifnet *ifp)
{
        struct me_softc *sc;

        sx_xlock(&me_ioctl_sx);
        sc = ifp->if_softc;
        me_delete_tunnel(sc);
        bpfdetach(ifp);
        if_detach(ifp);
        ifp->if_softc = NULL;
        sx_xunlock(&me_ioctl_sx);

        ME_WAIT();
        if_free(ifp);
        free(sc, M_IFME);
}

static int
me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
        struct ifreq *ifr = (struct ifreq *)data;
        struct sockaddr_in *src, *dst;
        struct me_softc *sc;
        int error;

        switch (cmd) {
        case SIOCSIFMTU:
                if (ifr->ifr_mtu < 576)
                        return (EINVAL);
                ifp->if_mtu = ifr->ifr_mtu;
                return (0);
        case SIOCSIFADDR:
                ifp->if_flags |= IFF_UP;
        case SIOCSIFFLAGS:
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                return (0);
        }
        sx_xlock(&me_ioctl_sx);
        sc = ifp->if_softc;
        if (sc == NULL) {
                error = ENXIO;
                goto end;
        }
        error = 0;
        switch (cmd) {
        case SIOCSIFPHYADDR:
                src = &((struct in_aliasreq *)data)->ifra_addr;
                dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
                if (src->sin_family != dst->sin_family ||
                    src->sin_family != AF_INET ||
                    src->sin_len != dst->sin_len ||
                    src->sin_len != sizeof(struct sockaddr_in)) {
                        error = EINVAL;
                        break;
                }
                if (src->sin_addr.s_addr == INADDR_ANY ||
                    dst->sin_addr.s_addr == INADDR_ANY) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                error = me_set_tunnel(sc, src->sin_addr.s_addr,
                    dst->sin_addr.s_addr);
                break;
        case SIOCDIFPHYADDR:
                me_delete_tunnel(sc);
                break;
        case SIOCGIFPSRCADDR:
        case SIOCGIFPDSTADDR:
                if (!ME_READY(sc)) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                src = (struct sockaddr_in *)&ifr->ifr_addr;
                memset(src, 0, sizeof(*src));
                src->sin_family = AF_INET;
                src->sin_len = sizeof(*src);
                switch (cmd) {
                case SIOCGIFPSRCADDR:
                        src->sin_addr = sc->me_src;
                        break;
                case SIOCGIFPDSTADDR:
                        src->sin_addr = sc->me_dst;
                        break;
                }
                error = prison_if(curthread->td_ucred, sintosa(src));
                if (error != 0)
                        memset(src, 0, sizeof(*src));
                break;
        case SIOCGTUNFIB:
                ifr->ifr_fib = sc->me_fibnum;
                break;
        case SIOCSTUNFIB:
                if ((error = priv_check(curthread, PRIV_NET_ME)) != 0)
                        break;
                if (ifr->ifr_fib >= rt_numfibs)
                        error = EINVAL;
                else
                        sc->me_fibnum = ifr->ifr_fib;
                break;
        default:
                error = EINVAL;
                break;
        }
end:
        sx_xunlock(&me_ioctl_sx);
        return (error);
}

static int
me_lookup(const struct mbuf *m, int off, int proto, void **arg)
{
        const struct ip *ip;
        struct me_softc *sc;

        if (V_me_hashtbl == NULL)
                return (0);

        NET_EPOCH_ASSERT();
        ip = mtod(m, const struct ip *);
        CK_LIST_FOREACH(sc, &ME_HASH(ip->ip_dst.s_addr,
            ip->ip_src.s_addr), chain) {
                if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
                    sc->me_dst.s_addr == ip->ip_src.s_addr) {
                        if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
                                return (0);
                        *arg = sc;
                        return (ENCAP_DRV_LOOKUP);
                }
        }
        return (0);
}

/*
 * Check that ingress address belongs to local host.
 */
static void
me_set_running(struct me_softc *sc)
{

        if (in_localip(sc->me_src))
                ME2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
        else
                ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
}

/*
 * ifaddr_event handler.
 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
 * source address spoofing.
 */
static void
me_srcaddr(void *arg __unused, const struct sockaddr *sa,
    int event __unused)
{
        const struct sockaddr_in *sin;
        struct me_softc *sc;

        /* Check that VNET is ready */
        if (V_me_hashtbl == NULL)
                return;

        NET_EPOCH_ASSERT();
        sin = (const struct sockaddr_in *)sa;
        CK_LIST_FOREACH(sc, &ME_SRCHASH(sin->sin_addr.s_addr), srchash) {
                if (sc->me_src.s_addr != sin->sin_addr.s_addr)
                        continue;
                me_set_running(sc);
        }
}

static int
me_set_tunnel(struct me_softc *sc, in_addr_t src, in_addr_t dst)
{
        struct epoch_tracker et;
        struct me_softc *tmp;

        sx_assert(&me_ioctl_sx, SA_XLOCKED);

        if (V_me_hashtbl == NULL) {
                V_me_hashtbl = me_hashinit();
                V_me_srchashtbl = me_hashinit();
        }

        if (sc->me_src.s_addr == src && sc->me_dst.s_addr == dst)
                return (0);

        CK_LIST_FOREACH(tmp, &ME_HASH(src, dst), chain) {
                if (tmp == sc)
                        continue;
                if (tmp->me_src.s_addr == src &&
                    tmp->me_dst.s_addr == dst)
                        return (EADDRNOTAVAIL);
        }

        me_delete_tunnel(sc);
        sc->me_dst.s_addr = dst;
        sc->me_src.s_addr = src;
        CK_LIST_INSERT_HEAD(&ME_HASH(src, dst), sc, chain);
        CK_LIST_INSERT_HEAD(&ME_SRCHASH(src), sc, srchash);

        NET_EPOCH_ENTER(et);
        me_set_running(sc);
        NET_EPOCH_EXIT(et);
        if_link_state_change(ME2IFP(sc), LINK_STATE_UP);
        return (0);
}

static void
me_delete_tunnel(struct me_softc *sc)
{

        sx_assert(&me_ioctl_sx, SA_XLOCKED);
        if (ME_READY(sc)) {
                CK_LIST_REMOVE(sc, chain);
                CK_LIST_REMOVE(sc, srchash);
                ME_WAIT();

                sc->me_src.s_addr = 0;
                sc->me_dst.s_addr = 0;
                ME2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
                if_link_state_change(ME2IFP(sc), LINK_STATE_DOWN);
        }
}

static uint16_t
me_in_cksum(uint16_t *p, int nwords)
{
        uint32_t sum = 0;

        while (nwords-- > 0)
                sum += *p++;
        sum = (sum >> 16) + (sum & 0xffff);
        sum += (sum >> 16);
        return (~sum);
}

static int
me_input(struct mbuf *m, int off, int proto, void *arg)
{
        struct me_softc *sc = arg;
        struct mobhdr *mh;
        struct ifnet *ifp;
        struct ip *ip;
        int hlen;

        NET_EPOCH_ASSERT();

        ifp = ME2IFP(sc);
        /* checks for short packets */
        hlen = sizeof(struct mobhdr);
        if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
                hlen -= sizeof(struct in_addr);
        if (m->m_len < sizeof(struct ip) + hlen)
                m = m_pullup(m, sizeof(struct ip) + hlen);
        if (m == NULL)
                goto drop;
        mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
        /* check for wrong flags */
        if (mh->mob_flags & (~MOB_FLAGS_SP)) {
                m_freem(m);
                goto drop;
        }
        if (mh->mob_flags) {
               if (hlen != sizeof(struct mobhdr)) {
                        m_freem(m);
                        goto drop;
               }
        } else
                hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
        /* check mobile header checksum */
        if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
                m_freem(m);
                goto drop;
        }
#ifdef MAC
        mac_ifnet_create_mbuf(ifp, m);
#endif
        ip = mtod(m, struct ip *);
        ip->ip_dst = mh->mob_dst;
        ip->ip_p = mh->mob_proto;
        ip->ip_sum = 0;
        ip->ip_len = htons(m->m_pkthdr.len - hlen);
        if (mh->mob_flags)
                ip->ip_src = mh->mob_src;
        memmove(mtodo(m, hlen), ip, sizeof(struct ip));
        m_adj(m, hlen);
        m_clrprotoflags(m);
        m->m_pkthdr.rcvif = ifp;
        m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
        M_SETFIB(m, ifp->if_fib);
        hlen = AF_INET;
        BPF_MTAP2(ifp, &hlen, sizeof(hlen), m);
        if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
        if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
        if ((ifp->if_flags & IFF_MONITOR) != 0)
                m_freem(m);
        else
                netisr_dispatch(NETISR_IP, m);
        return (IPPROTO_DONE);
drop:
        if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
        return (IPPROTO_DONE);
}

static int
me_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
   struct route *ro)
{
        uint32_t af;

        /* BPF writes need to be handled specially. */
        if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
                bcopy(dst->sa_data, &af, sizeof(af));
        else
                af = RO_GET_FAMILY(ro, dst);
        m->m_pkthdr.csum_data = af;
        return (ifp->if_transmit(ifp, m));
}

#define MTAG_ME 1414491977
static int
me_transmit(struct ifnet *ifp, struct mbuf *m)
{
        ME_RLOCK_TRACKER;
        struct mobhdr mh;
        struct me_softc *sc;
        struct ip *ip;
        uint32_t af;
        int error, hlen, plen;

        ME_RLOCK();
#ifdef MAC
        error = mac_ifnet_check_transmit(ifp, m);
        if (error != 0)
                goto drop;
#endif
        error = ENETDOWN;
        sc = ifp->if_softc;
        if (sc == NULL || !ME_READY(sc) ||
            (ifp->if_flags & IFF_MONITOR) != 0 ||
            (ifp->if_flags & IFF_UP) == 0 ||
            (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
            (error = if_tunnel_check_nesting(ifp, m, MTAG_ME,
                V_max_me_nesting)) != 0) {
                m_freem(m);
                goto drop;
        }
        af = m->m_pkthdr.csum_data;
        if (af != AF_INET) {
                error = EAFNOSUPPORT;
                m_freem(m);
                goto drop;
        }
        if (m->m_len < sizeof(struct ip))
                m = m_pullup(m, sizeof(struct ip));
        if (m == NULL) {
                error = ENOBUFS;
                goto drop;
        }
        ip = mtod(m, struct ip *);
        /* Fragmented datagramms shouldn't be encapsulated */
        if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
                error = EINVAL;
                m_freem(m);
                goto drop;
        }
        mh.mob_proto = ip->ip_p;
        mh.mob_src = ip->ip_src;
        mh.mob_dst = ip->ip_dst;
        if (in_hosteq(sc->me_src, ip->ip_src)) {
                hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
                mh.mob_flags = 0;
        } else {
                hlen = sizeof(struct mobhdr);
                mh.mob_flags = MOB_FLAGS_SP;
        }
        BPF_MTAP2(ifp, &af, sizeof(af), m);
        plen = m->m_pkthdr.len;
        ip->ip_src = sc->me_src;
        ip->ip_dst = sc->me_dst;
        m->m_flags &= ~(M_BCAST|M_MCAST);
        M_SETFIB(m, sc->me_fibnum);
        M_PREPEND(m, hlen, M_NOWAIT);
        if (m == NULL) {
                error = ENOBUFS;
                goto drop;
        }
        if (m->m_len < sizeof(struct ip) + hlen)
                m = m_pullup(m, sizeof(struct ip) + hlen);
        if (m == NULL) {
                error = ENOBUFS;
                goto drop;
        }
        memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
        ip = mtod(m, struct ip *);
        ip->ip_len = htons(m->m_pkthdr.len);
        ip->ip_p = IPPROTO_MOBILE;
        ip->ip_sum = 0;
        mh.mob_csum = 0;
        mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
        bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
        error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
drop:
        if (error)
                if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
        else {
                if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
                if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
        }
        ME_RUNLOCK();
        return (error);
}

static void
me_qflush(struct ifnet *ifp __unused)
{

}

static const struct srcaddrtab *me_srcaddrtab = NULL;
static const struct encaptab *ecookie = NULL;
static const struct encap_config me_encap_cfg = {
        .proto = IPPROTO_MOBILE,
        .min_length = sizeof(struct ip) + sizeof(struct mobhdr) -
            sizeof(in_addr_t),
        .exact_match = ENCAP_DRV_LOOKUP,
        .lookup = me_lookup,
        .input = me_input
};

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

        switch (type) {
        case MOD_LOAD:
                me_srcaddrtab = ip_encap_register_srcaddr(me_srcaddr,
                    NULL, M_WAITOK);
                ecookie = ip_encap_attach(&me_encap_cfg, NULL, M_WAITOK);
                break;
        case MOD_UNLOAD:
                ip_encap_detach(ecookie);
                ip_encap_unregister_srcaddr(me_srcaddrtab);
                break;
        default:
                return (EOPNOTSUPP);
        }
        return (0);
}

static moduledata_t me_mod = {
        "if_me",
        memodevent,
        0
};

DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(if_me, 1);