/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
 * Copyright (c) 2004-2008 Qing Li. All rights reserved.
 * Copyright (c) 2008 Kip Macy. 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 AUTHOR 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 AUTHOR 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.
 */
#include <sys/cdefs.h>
#include "opt_ddb.h"
#include "opt_inet.h"
#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>

#ifdef DDB
#include <ddb/ddb.h>
#endif

#include <vm/uma.h>

#include <netinet/in.h>
#include <net/if_llatbl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/route.h>
#include <net/route/route_ctl.h>
#include <net/route/route_debug.h>
#include <net/vnet.h>
#include <netinet/if_ether.h>
#include <netinet6/in6_var.h>
#include <netinet6/nd6.h>

MALLOC_DEFINE(M_LLTABLE, "lltable", "link level address tables");

VNET_DEFINE_STATIC(SLIST_HEAD(, lltable), lltables) =
    SLIST_HEAD_INITIALIZER(lltables);
#define V_lltables      VNET(lltables)

static struct rwlock lltable_list_lock;
RW_SYSINIT(lltable_list_lock, &lltable_list_lock, "lltable_list_lock");
#define LLTABLE_LIST_RLOCK()            rw_rlock(&lltable_list_lock)
#define LLTABLE_LIST_RUNLOCK()          rw_runlock(&lltable_list_lock)
#define LLTABLE_LIST_WLOCK()            rw_wlock(&lltable_list_lock)
#define LLTABLE_LIST_WUNLOCK()          rw_wunlock(&lltable_list_lock)
#define LLTABLE_LIST_LOCK_ASSERT()      rw_assert(&lltable_list_lock, RA_LOCKED)

static void lltable_unlink(struct lltable *llt);
static void llentries_unlink(struct lltable *llt, struct llentries *head);

/*
 * Dump lle state for a specific address family.
 */
static int
lltable_dump_af(struct lltable *llt, struct sysctl_req *wr)
{
        struct epoch_tracker et;
        int error;

        LLTABLE_LIST_LOCK_ASSERT();

        if (llt->llt_ifp->if_flags & IFF_LOOPBACK)
                return (0);
        error = 0;

        NET_EPOCH_ENTER(et);
        error = lltable_foreach_lle(llt,
            (llt_foreach_cb_t *)llt->llt_dump_entry, wr);
        NET_EPOCH_EXIT(et);

        return (error);
}

/*
 * Dump arp state for a specific address family.
 */
int
lltable_sysctl_dumparp(int af, struct sysctl_req *wr)
{
        struct lltable *llt;
        int error = 0;

        LLTABLE_LIST_RLOCK();
        SLIST_FOREACH(llt, &V_lltables, llt_link) {
                if (llt->llt_af == af) {
                        error = lltable_dump_af(llt, wr);
                        if (error != 0)
                                goto done;
                }
        }
done:
        LLTABLE_LIST_RUNLOCK();
        return (error);
}

/*
 * Adds a mbuf to hold queue. Drops old packets if the queue is full.
 *
 * Returns the number of held packets that were dropped.
 */
size_t
lltable_append_entry_queue(struct llentry *lle, struct mbuf *m,
    size_t maxheld)
{
        size_t pkts_dropped = 0;

        LLE_WLOCK_ASSERT(lle);

        while (lle->la_numheld >= maxheld && lle->la_hold != NULL) {
                struct mbuf *next = lle->la_hold->m_nextpkt;
                m_freem(lle->la_hold);
                lle->la_hold = next;
                lle->la_numheld--;
                pkts_dropped++;
        }

        if (lle->la_hold != NULL) {
                struct mbuf *curr = lle->la_hold;
                while (curr->m_nextpkt != NULL)
                        curr = curr->m_nextpkt;
                curr->m_nextpkt = m;
        } else
                lle->la_hold = m;

        lle->la_numheld++;

        return pkts_dropped;
}


/*
 * Common function helpers for chained hash table.
 */

/*
 * Runs specified callback for each entry in @llt.
 * Caller does the locking.
 *
 */
static int
htable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f, void *farg)
{
        struct llentry *lle, *next;
        int i, error;

        error = 0;

        for (i = 0; i < llt->llt_hsize; i++) {
                CK_LIST_FOREACH_SAFE(lle, &llt->lle_head[i], lle_next, next) {
                        error = f(llt, lle, farg);
                        if (error != 0)
                                break;
                }
        }

        return (error);
}

/*
 * The htable_[un]link_entry() functions return:
 * 0 if the entry was (un)linked already and nothing changed,
 * 1 if the entry was added/removed to/from the table, and
 * -1 on error (e.g., not being able to add the entry due to limits reached).
 * While the "unlink" operation should never error, callers of
 * lltable_link_entry() need to check for errors and handle them.
 */
static int
htable_link_entry(struct lltable *llt, struct llentry *lle)
{
        struct llentries *lleh;
        uint32_t hashidx;

        if ((lle->la_flags & LLE_LINKED) != 0)
                return (0);

        LLTABLE_LOCK_ASSERT(llt);

        if (llt->llt_maxentries > 0 &&
            llt->llt_entries >= llt->llt_maxentries)
                return (-1);

        hashidx = llt->llt_hash(lle, llt->llt_hsize);
        lleh = &llt->lle_head[hashidx];

        lle->lle_tbl  = llt;
        lle->lle_head = lleh;
        lle->la_flags |= LLE_LINKED;
        CK_LIST_INSERT_HEAD(lleh, lle, lle_next);
        llt->llt_entries++;

        return (1);
}

static int
htable_unlink_entry(struct llentry *lle)
{
        struct lltable *llt;

        if ((lle->la_flags & LLE_LINKED) == 0)
                return (0);

        llt = lle->lle_tbl;
        LLTABLE_LOCK_ASSERT(llt);
        KASSERT(llt->llt_entries > 0, ("%s: lltable %p (%s) entries %d <= 0",
            __func__, llt, if_name(llt->llt_ifp), llt->llt_entries));

        CK_LIST_REMOVE(lle, lle_next);
        lle->la_flags &= ~(LLE_VALID | LLE_LINKED);
#if 0
        lle->lle_tbl = NULL;
        lle->lle_head = NULL;
#endif
        llt->llt_entries--;

        return (1);
}

struct prefix_match_data {
        const struct sockaddr *addr;
        const struct sockaddr *mask;
        struct llentries dchain;
        u_int flags;
};

static int
htable_prefix_free_cb(struct lltable *llt, struct llentry *lle, void *farg)
{
        struct prefix_match_data *pmd;

        pmd = (struct prefix_match_data *)farg;

        if (llt->llt_match_prefix(pmd->addr, pmd->mask, pmd->flags, lle)) {
                LLE_WLOCK(lle);
                CK_LIST_INSERT_HEAD(&pmd->dchain, lle, lle_chain);
        }

        return (0);
}

static void
htable_prefix_free(struct lltable *llt, const struct sockaddr *addr,
    const struct sockaddr *mask, u_int flags)
{
        struct llentry *lle, *next;
        struct prefix_match_data pmd;

        bzero(&pmd, sizeof(pmd));
        pmd.addr = addr;
        pmd.mask = mask;
        pmd.flags = flags;
        CK_LIST_INIT(&pmd.dchain);

        LLTABLE_LOCK(llt);
        /* Push matching lles to chain */
        lltable_foreach_lle(llt, htable_prefix_free_cb, &pmd);

        llentries_unlink(llt, &pmd.dchain);
        LLTABLE_UNLOCK(llt);

        CK_LIST_FOREACH_SAFE(lle, &pmd.dchain, lle_chain, next)
                lltable_free_entry(llt, lle);
}

static void
htable_free_tbl(struct lltable *llt)
{

        mtx_destroy(&llt->llt_lock);
        free(llt->lle_head, M_LLTABLE);
        free(llt, M_LLTABLE);
}

static void
llentries_unlink(struct lltable *llt, struct llentries *head)
{
        struct llentry *lle, *next;

        CK_LIST_FOREACH_SAFE(lle, head, lle_chain, next)
                llt->llt_unlink_entry(lle);
}

/*
 * Helper function used to drop all mbufs in hold queue.
 *
 * Returns the number of held packets, if any, that were dropped.
 */
size_t
lltable_drop_entry_queue(struct llentry *lle)
{
        size_t pkts_dropped = 0;

        LLE_WLOCK_ASSERT(lle);

        while (lle->la_hold != NULL) {
                struct mbuf *next = lle->la_hold->m_nextpkt;
                m_freem(lle->la_hold);
                lle->la_hold = next;
                lle->la_numheld--;
                pkts_dropped++;
        }

        KASSERT(lle->la_numheld == 0,
                ("%s: la_numheld %d > 0, pkts_dropped %zd", __func__,
                 lle->la_numheld, pkts_dropped));

        return (pkts_dropped);
}

void
lltable_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
    const char *linkhdr, size_t linkhdrsize, int lladdr_off)
{

        memcpy(lle->r_linkdata, linkhdr, linkhdrsize);
        lle->r_hdrlen = linkhdrsize;
        lle->ll_addr = &lle->r_linkdata[lladdr_off];
        lle->la_flags |= LLE_VALID;
        lle->r_flags |= RLLE_VALID;
}

/*
 * Acquires lltable write lock.
 *
 * Returns true on success, with both lltable and lle lock held.
 * On failure, false is returned and lle wlock is still held.
 */
bool
lltable_trylock(struct llentry *lle)
{
        NET_EPOCH_ASSERT();

        LLE_WUNLOCK(lle);
        LLTABLE_LOCK(lle->lle_tbl);
        LLE_WLOCK(lle);

        /*
         * Since we droppped LLE lock, other thread might have deleted
         * this lle. Check and return
         */
        if ((lle->la_flags & LLE_DELETED) != 0) {
                LLTABLE_UNLOCK(lle->lle_tbl);
                return (false);
        }

        return (true);
}

/*
 * Tries to update @lle link-level address.
 * Since update requires AFDATA WLOCK, function
 * drops @lle lock, acquires AFDATA lock and then acquires
 * @lle lock to maintain lock order.
 *
 * Returns 1 on success.
 */
int
lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
    const char *linkhdr, size_t linkhdrsize, int lladdr_off)
{

        if (!lltable_trylock(lle))
                return (0);

        /* Update data */
        lltable_set_entry_addr(ifp, lle, linkhdr, linkhdrsize, lladdr_off);

        LLTABLE_UNLOCK(lle->lle_tbl);

        return (1);
}

 /*
 * Helper function used to pre-compute full/partial link-layer
 * header data suitable for feeding into if_output().
 */
int
lltable_calc_llheader(struct ifnet *ifp, int family, char *lladdr,
    char *buf, size_t *bufsize, int *lladdr_off)
{
        struct if_encap_req ereq;
        int error;

        bzero(buf, *bufsize);
        bzero(&ereq, sizeof(ereq));
        ereq.buf = buf;
        ereq.bufsize = *bufsize;
        ereq.rtype = IFENCAP_LL;
        ereq.family = family;
        ereq.lladdr = lladdr;
        ereq.lladdr_len = ifp->if_addrlen;
        error = ifp->if_requestencap(ifp, &ereq);
        if (error == 0) {
                *bufsize = ereq.bufsize;
                *lladdr_off = ereq.lladdr_off;
        }

        return (error);
}

/*
 * Searches for the child entry matching @family inside @lle.
 * Returns the entry or NULL.
 */
struct llentry *
llentry_lookup_family(struct llentry *lle, int family)
{
        struct llentry *child_lle;

        if (lle == NULL)
                return (NULL);

        CK_SLIST_FOREACH(child_lle, &lle->lle_children, lle_child_next) {
                if (child_lle->r_family == family)
                        return (child_lle);
        }

        return (NULL);
}

/*
 * Retrieves upper protocol family for the llentry.
 * By default, all "normal" (e.g. upper_family == transport_family)
 * llentries have r_family set to 0.
 * Thus, use @default_family in that regard, otherwise use r_family.
 *
 * Returns upper protocol family
 */
int
llentry_get_upper_family(const struct llentry *lle, int default_family)
{
        return (lle->r_family == 0 ? default_family : lle->r_family);
}

/*
 * Prints llentry @lle data into provided buffer.
 * Example: lle/inet/valid/em0/1.2.3.4
 *
 * Returns @buf.
 */
char *
llentry_print_buf(const struct llentry *lle, struct ifnet *ifp, int family,
    char *buf, size_t bufsize)
{
#if defined(INET) || defined(INET6)
        char abuf[INET6_ADDRSTRLEN];
#endif

        const char *valid = (lle->r_flags & RLLE_VALID) ? "valid" : "no_l2";
        const char *upper_str = rib_print_family(llentry_get_upper_family(lle, family));

        switch (family) {
#ifdef INET
        case AF_INET:
                inet_ntop(AF_INET, &lle->r_l3addr.addr4, abuf, sizeof(abuf));
                snprintf(buf, bufsize, "lle/%s/%s/%s/%s", upper_str,
                    valid, if_name(ifp), abuf);
                break;
#endif
#ifdef INET6
        case AF_INET6:
                inet_ntop(AF_INET6, &lle->r_l3addr.addr6, abuf, sizeof(abuf));
                snprintf(buf, bufsize, "lle/%s/%s/%s/%s", upper_str,
                    valid, if_name(ifp), abuf);
                break;
#endif
        default:
                snprintf(buf, bufsize, "lle/%s/%s/%s/????", upper_str,
                    valid, if_name(ifp));
                break;
        }

        return (buf);
}

char *
llentry_print_buf_lltable(const struct llentry *lle, char *buf, size_t bufsize)
{
        struct lltable *tbl = lle->lle_tbl;

        return (llentry_print_buf(lle, lltable_get_ifp(tbl), lltable_get_af(tbl), buf, bufsize));
}

/*
 * Requests feedback from the datapath.
 * First packet using @lle should result in
 * setting r_skip_req back to 0 and updating
 * lle_hittime to the current time_uptime.
 */
void
llentry_request_feedback(struct llentry *lle)
{
        struct llentry *child_lle;

        LLE_REQ_LOCK(lle);
        lle->r_skip_req = 1;
        LLE_REQ_UNLOCK(lle);

        CK_SLIST_FOREACH(child_lle, &lle->lle_children, lle_child_next) {
                LLE_REQ_LOCK(child_lle);
                child_lle->r_skip_req = 1;
                LLE_REQ_UNLOCK(child_lle);
        }
}

/*
 * Updates the lle state to mark it has been used
 * and record the time.
 * Used by the llentry_provide_feedback() wrapper.
 */
void
llentry_mark_used(struct llentry *lle)
{
        LLE_REQ_LOCK(lle);
        lle->r_skip_req = 0;
        lle->lle_hittime = time_uptime;
        LLE_REQ_UNLOCK(lle);
}

/*
 * Fetches the time when lle was used.
 * Return 0 if the entry was not used, relevant time_uptime
 *  otherwise.
 */
static time_t
llentry_get_hittime_raw(struct llentry *lle)
{
        time_t lle_hittime = 0;

        LLE_REQ_LOCK(lle);
        if ((lle->r_skip_req == 0) && (lle_hittime < lle->lle_hittime))
                lle_hittime = lle->lle_hittime;
        LLE_REQ_UNLOCK(lle);

        return (lle_hittime);
}

time_t
llentry_get_hittime(struct llentry *lle)
{
        time_t lle_hittime = 0;
        struct llentry *child_lle;

        lle_hittime = llentry_get_hittime_raw(lle);

        CK_SLIST_FOREACH(child_lle, &lle->lle_children, lle_child_next) {
                time_t hittime = llentry_get_hittime_raw(child_lle);
                if (hittime > lle_hittime)
                        lle_hittime = hittime;
        }

        return (lle_hittime);
}

/*
 * Update link-layer header for given @lle after
 * interface lladdr was changed.
 */
static int
llentry_update_ifaddr(struct lltable *llt, struct llentry *lle, void *farg)
{
        struct ifnet *ifp;
        u_char linkhdr[LLE_MAX_LINKHDR];
        size_t linkhdrsize;
        u_char *lladdr;
        int lladdr_off;

        ifp = (struct ifnet *)farg;

        lladdr = lle->ll_addr;

        LLE_WLOCK(lle);
        if ((lle->la_flags & LLE_VALID) == 0) {
                LLE_WUNLOCK(lle);
                return (0);
        }

        if ((lle->la_flags & LLE_IFADDR) != 0)
                lladdr = IF_LLADDR(ifp);

        linkhdrsize = sizeof(linkhdr);
        lltable_calc_llheader(ifp, llt->llt_af, lladdr, linkhdr, &linkhdrsize,
            &lladdr_off);
        memcpy(lle->r_linkdata, linkhdr, linkhdrsize);
        LLE_WUNLOCK(lle);

        return (0);
}

/*
 * Update all calculated headers for given @llt
 */
void
lltable_update_ifaddr(struct lltable *llt)
{

        if (llt->llt_ifp->if_flags & IFF_LOOPBACK)
                return;

        LLTABLE_LOCK(llt);
        lltable_foreach_lle(llt, llentry_update_ifaddr, llt->llt_ifp);
        LLTABLE_UNLOCK(llt);
}

/*
 *
 * Performs generic cleanup routines and frees lle.
 *
 * Called for non-linked entries, with callouts and
 * other AF-specific cleanups performed.
 *
 * @lle must be passed WLOCK'ed
 *
 * Returns the number of held packets, if any, that were dropped.
 */
size_t
llentry_free(struct llentry *lle)
{
        size_t pkts_dropped;

        LLE_WLOCK_ASSERT(lle);

        KASSERT((lle->la_flags & LLE_LINKED) == 0, ("freeing linked lle"));

        pkts_dropped = lltable_drop_entry_queue(lle);

        /* cancel timer */
        if (callout_stop(&lle->lle_timer) > 0)
                LLE_REMREF(lle);
        LLE_FREE_LOCKED(lle);

        return (pkts_dropped);
}

/*
 * Free all entries from given table and free itself.
 */

static int
lltable_free_cb(struct lltable *llt, struct llentry *lle, void *farg)
{
        struct llentries *dchain;

        dchain = (struct llentries *)farg;

        LLE_WLOCK(lle);
        CK_LIST_INSERT_HEAD(dchain, lle, lle_chain);

        return (0);
}

/*
 * Free all entries from given table and free itself.
 */
void
lltable_free(struct lltable *llt)
{
        struct llentry *lle, *next;
        struct llentries dchain;

        KASSERT(llt != NULL, ("%s: llt is NULL", __func__));

        lltable_unlink(llt);

        CK_LIST_INIT(&dchain);
        LLTABLE_LOCK(llt);
        /* Push all lles to @dchain */
        lltable_foreach_lle(llt, lltable_free_cb, &dchain);
        llentries_unlink(llt, &dchain);
        LLTABLE_UNLOCK(llt);

        CK_LIST_FOREACH_SAFE(lle, &dchain, lle_chain, next) {
                llentry_free(lle);
        }

        KASSERT(llt->llt_entries == 0, ("%s: lltable %p (%s) entries not 0: %d",
            __func__, llt, llt->llt_ifp->if_xname, llt->llt_entries));

        llt->llt_free_tbl(llt);
}

/*
 * Deletes an address from given lltable.
 * Used for userland interaction to remove
 * individual entries. Skips entries added by OS.
 */
int
lltable_delete_addr(struct lltable *llt, u_int flags,
    const struct sockaddr *l3addr)
{
        struct llentry *lle;

        LLTABLE_LOCK(llt);
        lle = lla_lookup(llt, LLE_SF(l3addr->sa_family, LLE_EXCLUSIVE), l3addr);

        if (lle == NULL) {
                LLTABLE_UNLOCK(llt);
                return (ENOENT);
        }
        if ((lle->la_flags & LLE_IFADDR) != 0 && (flags & LLE_IFADDR) == 0) {
                LLTABLE_UNLOCK(llt);
                LLE_WUNLOCK(lle);
                return (EPERM);
        }

        lltable_unlink_entry(llt, lle);
        LLTABLE_UNLOCK(llt);

        llt->llt_delete_entry(llt, lle);

        return (0);
}

void
lltable_prefix_free(int af, struct sockaddr *addr, struct sockaddr *mask,
    u_int flags)
{
        struct lltable *llt;

        LLTABLE_LIST_RLOCK();
        SLIST_FOREACH(llt, &V_lltables, llt_link) {
                if (llt->llt_af != af)
                        continue;

                llt->llt_prefix_free(llt, addr, mask, flags);
        }
        LLTABLE_LIST_RUNLOCK();
}

/*
 * Delete llentries that func() returns true.
 */
struct lle_match_data {
        struct llentries dchain;
        llt_match_cb_t *func;
        void *farg;
};

static int
lltable_delete_conditional_cb(struct lltable *llt, struct llentry *lle,
    void *farg)
{
        struct lle_match_data *lmd;

        lmd = (struct lle_match_data *)farg;
        if (lmd->func(llt, lle, lmd->farg)) {
                LLE_WLOCK(lle);
                CK_LIST_INSERT_HEAD(&lmd->dchain, lle, lle_chain);
        }

        return (0);
}

void
lltable_delete_conditional(struct lltable *llt, llt_match_cb_t *func,
    void *farg)
{
        struct llentry *lle, *next;
        struct lle_match_data lmd;

        bzero(&lmd, sizeof(lmd));
        CK_LIST_INIT(&lmd.dchain);
        lmd.func = func;
        lmd.farg = farg;

        LLTABLE_LOCK(llt);
        lltable_foreach_lle(llt, lltable_delete_conditional_cb, &lmd);
        llentries_unlink(llt, &lmd.dchain);
        LLTABLE_UNLOCK(llt);

        CK_LIST_FOREACH_SAFE(lle, &lmd.dchain, lle_chain, next)
                llt->llt_delete_entry(llt, lle);
}

struct lltable *
lltable_allocate_htbl(uint32_t hsize)
{
        struct lltable *llt;
        int i;

        llt = malloc(sizeof(struct lltable), M_LLTABLE, M_WAITOK | M_ZERO);
        llt->llt_hsize = hsize;
        llt->lle_head = malloc(sizeof(struct llentries) * hsize,
            M_LLTABLE, M_WAITOK | M_ZERO);
        mtx_init(&llt->llt_lock, "lltable", NULL, MTX_DEF);

        for (i = 0; i < llt->llt_hsize; i++)
                CK_LIST_INIT(&llt->lle_head[i]);

        /* Set some default callbacks */
        llt->llt_link_entry = htable_link_entry;
        llt->llt_unlink_entry = htable_unlink_entry;
        llt->llt_prefix_free = htable_prefix_free;
        llt->llt_foreach_entry = htable_foreach_lle;
        llt->llt_free_tbl = htable_free_tbl;

        return (llt);
}

/*
 * Links lltable to global llt list.
 */
void
lltable_link(struct lltable *llt)
{

        LLTABLE_LIST_WLOCK();
        SLIST_INSERT_HEAD(&V_lltables, llt, llt_link);
        LLTABLE_LIST_WUNLOCK();
}

static void
lltable_unlink(struct lltable *llt)
{

        LLTABLE_LIST_WLOCK();
        SLIST_REMOVE(&V_lltables, llt, lltable, llt_link);
        LLTABLE_LIST_WUNLOCK();

}

/*
 * Gets interface @ifp lltable for the specified @family
 */
struct lltable *
lltable_get(struct ifnet *ifp, int family)
{
        switch (family) {
#ifdef INET
        case AF_INET:
                return (in_lltable_get(ifp));
#endif
#ifdef INET6
        case AF_INET6:
                return (in6_lltable_get(ifp));
#endif
        }

        return (NULL);
}

/*
 * External methods used by lltable consumers
 */

int
lltable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f, void *farg)
{

        return (llt->llt_foreach_entry(llt, f, farg));
}

struct llentry *
lltable_alloc_entry(struct lltable *llt, u_int flags,
    const struct sockaddr *l3addr)
{

        return (llt->llt_alloc_entry(llt, flags, l3addr));
}

void
lltable_free_entry(struct lltable *llt, struct llentry *lle)
{

        llt->llt_free_entry(llt, lle);
}

int
lltable_link_entry(struct lltable *llt, struct llentry *lle)
{
        int error = llt->llt_link_entry(llt, lle);

        if (error == 0 && (lle->la_flags & LLE_PUB) != 0)
                llt->llt_flags |= LLT_ADDEDPROXY;

        return (error);
}

void
lltable_link_child_entry(struct llentry *lle, struct llentry *child_lle)
{
        child_lle->lle_parent = lle;
        child_lle->lle_tbl = lle->lle_tbl;
        child_lle->la_flags |= LLE_LINKED;
        CK_SLIST_INSERT_HEAD(&lle->lle_children, child_lle, lle_child_next);
}

void
lltable_unlink_child_entry(struct llentry *child_lle)
{
        struct llentry *lle = child_lle->lle_parent;

        child_lle->la_flags &= ~LLE_LINKED;
        child_lle->lle_parent = NULL;
        CK_SLIST_REMOVE(&lle->lle_children, child_lle, llentry, lle_child_next);
}

int
lltable_unlink_entry(struct lltable *llt, struct llentry *lle)
{

        return (llt->llt_unlink_entry(lle));
}

void
lltable_fill_sa_entry(const struct llentry *lle, struct sockaddr *sa)
{
        struct lltable *llt;

        llt = lle->lle_tbl;
        llt->llt_fill_sa_entry(lle, sa);
}

struct ifnet *
lltable_get_ifp(const struct lltable *llt)
{

        return (llt->llt_ifp);
}

int
lltable_get_af(const struct lltable *llt)
{

        return (llt->llt_af);
}

/*
 * Called in route_output when rtm_flags contains RTF_LLDATA.
 */
int
lla_rt_output(struct rt_msghdr *rtm, struct rt_addrinfo *info)
{
        struct sockaddr_dl *dl =
            (struct sockaddr_dl *)info->rti_info[RTAX_GATEWAY];
        struct sockaddr *dst = (struct sockaddr *)info->rti_info[RTAX_DST];
        struct ifnet *ifp;
        struct lltable *llt;
        struct llentry *lle, *lle_tmp;
        uint8_t linkhdr[LLE_MAX_LINKHDR];
        size_t linkhdrsize;
        int lladdr_off;
        u_int laflags = 0;
        int error;

        if (dl == NULL || dl->sdl_family != AF_LINK)
                return (EINVAL);

        /* XXX: should be ntohs() */
        ifp = ifnet_byindex(dl->sdl_index);
        if (ifp == NULL) {
                log(LOG_INFO, "%s: invalid ifp (sdl_index %d)\n",
                    __func__, dl->sdl_index);
                return EINVAL;
        }

        llt = lltable_get(ifp, dst->sa_family);

        if (llt == NULL)
                return (ESRCH);

        error = 0;

        switch (rtm->rtm_type) {
        case RTM_ADD:
                /* Add static LLE */
                laflags = 0;
                if (rtm->rtm_rmx.rmx_expire == 0)
                        laflags = LLE_STATIC;
                lle = lltable_alloc_entry(llt, laflags, dst);
                if (lle == NULL)
                        return (ENOMEM);

                linkhdrsize = sizeof(linkhdr);
                if (lltable_calc_llheader(ifp, dst->sa_family, LLADDR(dl),
                    linkhdr, &linkhdrsize, &lladdr_off) != 0) {
                        lltable_free_entry(llt, lle);
                        return (EINVAL);
                }
                lltable_set_entry_addr(ifp, lle, linkhdr, linkhdrsize,
                    lladdr_off);
                if ((rtm->rtm_flags & RTF_ANNOUNCE))
                        lle->la_flags |= LLE_PUB;
                lle->la_expire = rtm->rtm_rmx.rmx_expire;

                laflags = lle->la_flags;

                /* Try to link new entry */
                lle_tmp = NULL;
                LLTABLE_LOCK(llt);
                LLE_WLOCK(lle);
                lle_tmp = lla_lookup(llt, LLE_EXCLUSIVE, dst);
                if (lle_tmp != NULL) {
                        /* Check if we are trying to replace immutable entry */
                        if ((lle_tmp->la_flags & LLE_IFADDR) != 0) {
                                LLTABLE_UNLOCK(llt);
                                LLE_WUNLOCK(lle_tmp);
                                lltable_free_entry(llt, lle);
                                return (EPERM);
                        }
                        /* Unlink existing entry from table */
                        lltable_unlink_entry(llt, lle_tmp);
                }
                lltable_link_entry(llt, lle);
                LLTABLE_UNLOCK(llt);

                if (lle_tmp != NULL) {
                        EVENTHANDLER_INVOKE(lle_event, lle_tmp,LLENTRY_EXPIRED);
                        lltable_free_entry(llt, lle_tmp);
                }

                /*
                 * By invoking LLE handler here we might get
                 * two events on static LLE entry insertion
                 * in routing socket. However, since we might have
                 * other subscribers we need to generate this event.
                 */
                EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED);
                LLE_WUNLOCK(lle);
                llt->llt_post_resolved(llt, lle);
                break;

        case RTM_DELETE:
                return (lltable_delete_addr(llt, 0, dst));

        default:
                error = EINVAL;
        }

        return (error);
}

#ifdef DDB
static void
llatbl_lle_show(struct llentry *lle)
{
        uint8_t octet[6];
        sa_family_t af = AF_UNSPEC;
        char l3_addr_fmt[] = " l3_addr=%s (af=%d)\n";

        db_printf("lle=%p\n", lle);
        db_printf(" lle_next=%p\n", lle->lle_next.cle_next);
        db_printf(" lle_lock=%p\n", &lle->lle_lock);
        db_printf(" lle_tbl=%p\n", lle->lle_tbl);
        db_printf(" lle_head=%p\n", lle->lle_head);
        db_printf(" la_hold=%p\n", lle->la_hold);
        db_printf(" la_numheld=%d\n", lle->la_numheld);
        db_printf(" la_expire=%ju\n", (uintmax_t)lle->la_expire);
        db_printf(" la_flags=0x%04x\n", lle->la_flags);
        db_printf(" la_asked=%u\n", lle->la_asked);
        db_printf(" la_preempt=%u\n", lle->la_preempt);
        db_printf(" ln_state=%d\n", lle->ln_state);
        db_printf(" ln_router=%u\n", lle->ln_router);
        db_printf(" ln_ntick=%ju\n", (uintmax_t)lle->ln_ntick);
        db_printf(" lle_refcnt=%d\n", lle->lle_refcnt);
        bcopy(lle->ll_addr, octet, sizeof(octet));
        db_printf(" ll_addr=%02x:%02x:%02x:%02x:%02x:%02x\n",
            octet[0], octet[1], octet[2], octet[3], octet[4], octet[5]);
        db_printf(" lle_timer=%p\n", &lle->lle_timer);

        if (lle->lle_tbl) {
                af = lle->lle_tbl->llt_af;
        }

        switch (af) {
#ifdef INET
        case AF_INET:
        {
                struct sockaddr_in sin;
                char l3s[INET_ADDRSTRLEN];

                lltable_fill_sa_entry(lle, (struct sockaddr *)&sin);
                (void) inet_ntop(af, &sin.sin_addr, l3s, sizeof(l3s));
                db_printf(l3_addr_fmt, l3s, af);
                break;
        }
#endif
#ifdef INET6
        case AF_INET6:
        {
                struct sockaddr_in6 sin6;
                char l3s[INET6_ADDRSTRLEN];

                lltable_fill_sa_entry(lle, (struct sockaddr *)&sin6);
                (void) inet_ntop(af, &sin6.sin6_addr, l3s, sizeof(l3s));
                db_printf(l3_addr_fmt, l3s, af);
                break;
        }
#endif
        default:
                db_printf(l3_addr_fmt, "N/A", af);
                break;
        }
}

DB_SHOW_COMMAND(llentry, db_show_llentry)
{

        if (!have_addr) {
                db_printf("usage: show llentry <struct llentry *>\n");
                return;
        }

        llatbl_lle_show((struct llentry *)addr);
}

static void
llatbl_llt_show(struct lltable *llt)
{
        int i;
        struct llentry *lle;

        db_printf("llt=%p llt_af=%d llt_ifp=%p\n",
            llt, llt->llt_af, llt->llt_ifp);

        for (i = 0; i < llt->llt_hsize; i++) {
                CK_LIST_FOREACH(lle, &llt->lle_head[i], lle_next) {
                        llatbl_lle_show(lle);
                        if (db_pager_quit)
                                return;
                }
        }
}

DB_SHOW_COMMAND(lltable, db_show_lltable)
{

        if (!have_addr) {
                db_printf("usage: show lltable <struct lltable *>\n");
                return;
        }

        llatbl_llt_show((struct lltable *)addr);
}

DB_SHOW_ALL_COMMAND(lltables, db_show_all_lltables)
{
        VNET_ITERATOR_DECL(vnet_iter);
        struct lltable *llt;

        VNET_FOREACH(vnet_iter) {
                CURVNET_SET_QUIET(vnet_iter);
#ifdef VIMAGE
                db_printf("vnet=%p\n", curvnet);
#endif
                SLIST_FOREACH(llt, &V_lltables, llt_link) {
                        db_printf("llt=%p llt_af=%d llt_ifp=%p(%s)\n",
                            llt, llt->llt_af, llt->llt_ifp,
                            (llt->llt_ifp != NULL) ?
                                llt->llt_ifp->if_xname : "?");
                        if (have_addr && addr != 0) /* verbose */
                                llatbl_llt_show(llt);
                        if (db_pager_quit) {
                                CURVNET_RESTORE();
                                return;
                        }
                }
                CURVNET_RESTORE();
        }
}
#endif