/*      $NetBSD: route.c,v 1.240 2025/09/21 15:11:52 christos Exp $     */

/*-
 * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Kevin M. Lahey of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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) 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) 1980, 1986, 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. 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.
 *
 *      @(#)route.c     8.3 (Berkeley) 1/9/95
 */

#ifdef _KERNEL_OPT
#include "opt_inet.h"
#include "opt_route.h"
#include "opt_net_mpsafe.h"
#endif

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: route.c,v 1.240 2025/09/21 15:11:52 christos Exp $");

#include <sys/param.h>
#ifdef RTFLUSH_DEBUG
#include <sys/sysctl.h>
#endif
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/proc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <sys/pool.h>
#include <sys/kauth.h>
#include <sys/workqueue.h>
#include <sys/syslog.h>
#include <sys/rwlock.h>
#include <sys/mutex.h>
#include <sys/cpu.h>
#include <sys/kmem.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#if defined(INET) || defined(INET6)
#include <net/if_llatbl.h>
#endif

#include <netinet/in.h>
#include <netinet/in_var.h>

#define PRESERVED_RTF   (RTF_UP | RTF_GATEWAY | RTF_HOST | RTF_DONE | RTF_MASK)

#ifdef RTFLUSH_DEBUG
#define rtcache_debug() __predict_false(_rtcache_debug)
#else /* RTFLUSH_DEBUG */
#define rtcache_debug() 0
#endif /* RTFLUSH_DEBUG */

#ifdef RT_DEBUG
#define RT_REFCNT_TRACE(rt)     printf("%s:%d: rt=%p refcnt=%d\n", \
                                    __func__, __LINE__, (rt), (rt)->rt_refcnt)
#else
#define RT_REFCNT_TRACE(rt)     do {} while (0)
#endif

#ifdef RT_DEBUG
#define dlog(level, fmt, args...)       log(level, fmt, ##args)
#else
#define dlog(level, fmt, args...)       do {} while (0)
#endif

struct rtstat           rtstat;

static int              rttrash;        /* routes not in table but not freed */

static struct pool      rtentry_pool;
static struct pool      rttimer_pool;

static struct callout   rt_timer_ch; /* callout for rt_timer_timer() */
static struct workqueue *rt_timer_wq;
static struct work      rt_timer_wk;

static void     rt_timer_init(void);
static void     rt_timer_queue_remove_all(struct rttimer_queue *);
static void     rt_timer_remove_all(struct rtentry *);
static void     rt_timer_timer(void *);

/*
 * Locking notes:
 * - The routing table is protected by a global rwlock
 *   - API: RT_RLOCK and friends
 * - rtcaches are NOT protected by the framework
 *   - Callers must guarantee a rtcache isn't accessed simultaneously
 *   - How the constraint is guaranteed in the wild
 *     - Protect a rtcache by a mutex (e.g., inp_route)
 *     - Make rtcache per-CPU and allow only accesses from softint
 *       (e.g., ipforward_rt_percpu)
 * - References to a rtentry is managed by reference counting and psref
 *   - Reference counting is used for temporal reference when a rtentry
 *     is fetched from the routing table
 *   - psref is used for temporal reference when a rtentry is fetched
 *     from a rtcache
 *     - struct route (rtcache) has struct psref, so we cannot obtain
 *       a reference twice on the same struct route
 *   - Before destroying or updating a rtentry, we have to wait for
 *     all references left (see below for details)
 *   - APIs
 *     - An obtained rtentry via rtalloc1 or rtrequest* must be
 *       unreferenced by rt_unref
 *     - An obtained rtentry via rtcache_* must be unreferenced by
 *       rtcache_unref
 *   - TODO: once we get a lockless routing table, we should use only
 *           psref for rtentries
 * - rtentry destruction
 *   - A rtentry is destroyed (freed) only when we call rtrequest(RTM_DELETE)
 *   - If a caller of rtrequest grabs a reference of a rtentry, the caller
 *     has a responsibility to destroy the rtentry by itself by calling
 *     rt_free
 *     - If not, rtrequest itself does that
 *   - If rt_free is called in softint, the actual destruction routine is
 *     deferred to a workqueue
 * - rtentry update
 *   - When updating a rtentry, RTF_UPDATING flag is set
 *   - If a rtentry is set RTF_UPDATING, fetching the rtentry from
 *     the routing table or a rtcache results in either of the following
 *     cases:
 *     - if the caller runs in softint, the caller fails to fetch
 *     - otherwise, the caller waits for the update completed and retries
 *       to fetch (probably succeed to fetch for the second time)
 * - rtcache invalidation
 *   - There is a global generation counter that is incremented when
 *     any routes have been added or deleted
 *   - When a rtcache caches a rtentry into itself, it also stores
 *     a snapshot of the generation counter
 *   - If the snapshot equals to the global counter, the cache is valid,
 *     otherwise the cache is invalidated
 */

/*
 * Global lock for the routing table.
 */
static krwlock_t                rt_lock __cacheline_aligned;
#ifdef NET_MPSAFE
#define RT_RLOCK()              rw_enter(&rt_lock, RW_READER)
#define RT_WLOCK()              rw_enter(&rt_lock, RW_WRITER)
#define RT_UNLOCK()             rw_exit(&rt_lock)
#define RT_WLOCKED()            rw_write_held(&rt_lock)
#define RT_ASSERT_WLOCK()       KASSERT(rw_write_held(&rt_lock))
#define RT_WQ_FLAGS             WQ_MPSAFE
#else
#define RT_RLOCK()              do {} while (0)
#define RT_WLOCK()              do {} while (0)
#define RT_UNLOCK()             do {} while (0)
#define RT_WLOCKED()            true
#define RT_ASSERT_WLOCK()       do {} while (0)
#define RT_WQ_FLAGS             0
#endif

static uint64_t rtcache_generation;

/*
 * mutex and cv that are used to wait for references to a rtentry left
 * before updating the rtentry.
 */
static struct {
        kmutex_t                lock;
        kcondvar_t              cv;
        bool                    ongoing;
        const struct lwp        *lwp;
} rt_update_global __cacheline_aligned;

/*
 * A workqueue and stuff that are used to defer the destruction routine
 * of rtentries.
 */
static struct {
        struct workqueue        *wq;
        struct work             wk;
        kmutex_t                lock;
        SLIST_HEAD(, rtentry)   queue;
        bool                    enqueued;
} rt_free_global __cacheline_aligned;

/* psref for rtentry */
static struct psref_class *rt_psref_class __read_mostly;

#ifdef RTFLUSH_DEBUG
static int _rtcache_debug = 0;
#endif /* RTFLUSH_DEBUG */

static kauth_listener_t route_listener;

static int rtdeletemsg(struct rtentry *);

static void rt_maskedcopy(const struct sockaddr *,
    struct sockaddr *, const struct sockaddr *);

static void rtcache_invalidate(void);

static void rt_ref(struct rtentry *);

static struct rtentry *
    rtalloc1_locked(const struct sockaddr *, int, bool, bool);

static struct ifaddr *rt_getifa(struct rt_addrinfo *, struct psref *);
static struct ifnet *rt_getifp(struct rt_addrinfo *, struct psref *);
static struct ifaddr *ifa_ifwithroute_psref(int, const struct sockaddr *,
    const struct sockaddr *, struct psref *);

static void rtcache_ref(struct rtentry *, struct route *);

#ifdef NET_MPSAFE
static void rt_update_wait(void);
#endif

static bool rt_wait_ok(void);
static void rt_wait_refcnt(const char *, struct rtentry *, int);
static void rt_wait_psref(struct rtentry *);

#ifdef DDB
static void db_print_sa(const struct sockaddr *);
static void db_print_ifa(struct ifaddr *);
static int db_show_rtentry(struct rtentry *, void *);
#endif

#ifdef RTFLUSH_DEBUG
static void sysctl_net_rtcache_setup(struct sysctllog **);
static void
sysctl_net_rtcache_setup(struct sysctllog **clog)
{
        const struct sysctlnode *rnode;

        if (sysctl_createv(clog, 0, NULL, &rnode, CTLFLAG_PERMANENT,
            CTLTYPE_NODE,
            "rtcache", SYSCTL_DESCR("Route cache related settings"),
            NULL, 0, NULL, 0, CTL_NET, CTL_CREATE, CTL_EOL) != 0)
                return;
        if (sysctl_createv(clog, 0, &rnode, &rnode,
            CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT,
            "debug", SYSCTL_DESCR("Debug route caches"),
            NULL, 0, &_rtcache_debug, 0, CTL_CREATE, CTL_EOL) != 0)
                return;
}
#endif /* RTFLUSH_DEBUG */

static inline void
rt_destroy(struct rtentry *rt)
{
        if (rt->_rt_key != NULL)
                sockaddr_free(rt->_rt_key);
        if (rt->rt_gateway != NULL)
                sockaddr_free(rt->rt_gateway);
        if (rt_gettag(rt) != NULL)
                sockaddr_free(rt_gettag(rt));
        rt->_rt_key = rt->rt_gateway = rt->rt_tag = NULL;
}

static inline const struct sockaddr *
rt_setkey(struct rtentry *rt, const struct sockaddr *key, int flags)
{
        if (rt->_rt_key == key)
                goto out;

        if (rt->_rt_key != NULL)
                sockaddr_free(rt->_rt_key);
        rt->_rt_key = sockaddr_dup(key, flags);
out:
        rt->rt_nodes->rn_key = (const char *)rt->_rt_key;
        return rt->_rt_key;
}

struct ifaddr *
rt_get_ifa(struct rtentry *rt)
{
        struct ifaddr *ifa;

        ifa = rt->rt_ifa;
        if (ifa->ifa_getifa == NULL)
                return ifa;
#if 0
        else if (ifa->ifa_seqno != NULL && *ifa->ifa_seqno == rt->rt_ifa_seqno)
                return ifa;
#endif
        else {
                ifa = (*ifa->ifa_getifa)(ifa, rt_getkey(rt));
                if (ifa == NULL)
                        return NULL;
                rt_replace_ifa(rt, ifa);
                return ifa;
        }
}

static void
rt_set_ifa1(struct rtentry *rt, struct ifaddr *ifa)
{
        rt->rt_ifa = ifa;
        if (ifa->ifa_seqno != NULL)
                rt->rt_ifa_seqno = *ifa->ifa_seqno;
}

/*
 * Is this route the connected route for the ifa?
 */
static int
rt_ifa_connected(const struct rtentry *rt, const struct ifaddr *ifa)
{
        const struct sockaddr *key, *dst, *odst;
        struct sockaddr_storage maskeddst;

        key = rt_getkey(rt);
        dst = rt->rt_flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
        if (dst == NULL ||
            dst->sa_family != key->sa_family ||
            dst->sa_len != key->sa_len)
                return 0;
        if ((rt->rt_flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
                odst = dst;
                dst = (struct sockaddr *)&maskeddst;
                rt_maskedcopy(odst, (struct sockaddr *)&maskeddst,
                    ifa->ifa_netmask);
        }
        return (memcmp(dst, key, dst->sa_len) == 0);
}

void
rt_replace_ifa(struct rtentry *rt, struct ifaddr *ifa)
{
        struct ifaddr *old;

        if (rt->rt_ifa == ifa)
                return;

        if (rt->rt_ifa != ifa &&
            rt->rt_ifa->ifa_flags & IFA_ROUTE &&
            rt_ifa_connected(rt, rt->rt_ifa))
        {
                RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
                    "replace deleted IFA_ROUTE\n",
                    (void *)rt->_rt_key, (void *)rt->rt_ifa);
                rt->rt_ifa->ifa_flags &= ~IFA_ROUTE;
                if (rt_ifa_connected(rt, ifa)) {
                        RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
                            "replace added IFA_ROUTE\n",
                            (void *)rt->_rt_key, (void *)ifa);
                        ifa->ifa_flags |= IFA_ROUTE;
                }
        }

        ifaref(ifa);
        old = rt->rt_ifa;
        rt_set_ifa1(rt, ifa);
        ifafree(old);
}

static void
rt_set_ifa(struct rtentry *rt, struct ifaddr *ifa)
{
        ifaref(ifa);
        rt_set_ifa1(rt, ifa);
}

static int
route_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
    void *arg0, void *arg1, void *arg2, void *arg3)
{
        struct rt_msghdr *rtm;
        int result;

        result = KAUTH_RESULT_DEFER;
        rtm = arg1;

        if (action != KAUTH_NETWORK_ROUTE)
                return result;

        if (rtm->rtm_type == RTM_GET)
                result = KAUTH_RESULT_ALLOW;

        return result;
}

static void rt_free_work(struct work *, void *);

void
rt_init(void)
{
        int error;

#ifdef RTFLUSH_DEBUG
        sysctl_net_rtcache_setup(NULL);
#endif

        mutex_init(&rt_free_global.lock, MUTEX_DEFAULT, IPL_SOFTNET);
        SLIST_INIT(&rt_free_global.queue);
        rt_free_global.enqueued = false;

        rt_psref_class = psref_class_create("rtentry", IPL_SOFTNET);

        error = workqueue_create(&rt_free_global.wq, "rt_free",
            rt_free_work, NULL, PRI_USER, IPL_SOFTNET, RT_WQ_FLAGS);
        if (error)
                panic("%s: workqueue_create failed (%d)\n", __func__, error);

        mutex_init(&rt_update_global.lock, MUTEX_DEFAULT, IPL_SOFTNET);
        cv_init(&rt_update_global.cv, "rt_update");

        pool_init(&rtentry_pool, sizeof(struct rtentry), 0, 0, 0, "rtentpl",
            NULL, IPL_SOFTNET);
        pool_init(&rttimer_pool, sizeof(struct rttimer), 0, 0, 0, "rttmrpl",
            NULL, IPL_SOFTNET);

        rn_init();      /* initialize all zeroes, all ones, mask table */
        rtbl_init();

        route_listener = kauth_listen_scope(KAUTH_SCOPE_NETWORK,
            route_listener_cb, NULL);
}

static void
rtcache_invalidate(void)
{

        RT_ASSERT_WLOCK();

        if (rtcache_debug())
                printf("%s: enter\n", __func__);

        rtcache_generation++;
}

#ifdef RT_DEBUG
static void
dump_rt(const struct rtentry *rt)
{
        char buf[512];

        log(LOG_DEBUG, "rt: ");
        log(LOG_DEBUG, "p=%p ", rt);
        if (rt->_rt_key == NULL) {
                log(LOG_DEBUG, "dst=(NULL) ");
        } else {
                sockaddr_format(rt->_rt_key, buf, sizeof(buf));
                log(LOG_DEBUG, "dst=%s ", buf);
        }
        if (rt->rt_gateway == NULL) {
                log(LOG_DEBUG, "gw=(NULL) ");
        } else {
                sockaddr_format(rt->_rt_key, buf, sizeof(buf));
                log(LOG_DEBUG, "gw=%s ", buf);
        }
        log(LOG_DEBUG, "flags=%x ", rt->rt_flags);
        if (rt->rt_ifp == NULL) {
                log(LOG_DEBUG, "if=(NULL) ");
        } else {
                log(LOG_DEBUG, "if=%s ", rt->rt_ifp->if_xname);
        }
        log(LOG_DEBUG, "\n");
}
#endif /* RT_DEBUG */

/*
 * Packet routing routines. If success, refcnt of a returned rtentry
 * will be incremented. The caller has to rtfree it by itself.
 */
struct rtentry *
rtalloc1_locked(const struct sockaddr *dst, int report, bool wait_ok,
    bool wlock)
{
        rtbl_t *rtbl;
        struct rtentry *rt;
        int s;

#ifdef NET_MPSAFE
retry:
#endif
        s = splsoftnet();
        rtbl = rt_gettable(dst->sa_family);
        if (rtbl == NULL)
                goto miss;

        rt = rt_matchaddr(rtbl, dst);
        if (rt == NULL)
                goto miss;

        if (!ISSET(rt->rt_flags, RTF_UP))
                goto miss;

#ifdef NET_MPSAFE
        if (ISSET(rt->rt_flags, RTF_UPDATING) &&
            /* XXX updater should be always able to acquire */
            curlwp != rt_update_global.lwp) {
                if (!wait_ok || !rt_wait_ok())
                        goto miss;
                RT_UNLOCK();
                splx(s);

                /* We can wait until the update is complete */
                rt_update_wait();

                if (wlock)
                        RT_WLOCK();
                else
                        RT_RLOCK();
                goto retry;
        }
#endif /* NET_MPSAFE */

        rt_ref(rt);
        RT_REFCNT_TRACE(rt);

        splx(s);
        return rt;
miss:
        rtstat.rts_unreach++;
        if (report) {
                struct rt_addrinfo info;

                memset(&info, 0, sizeof(info));
                info.rti_info[RTAX_DST] = dst;
                rt_missmsg(RTM_MISS, &info, 0, 0);
        }
        splx(s);
        return NULL;
}

struct rtentry *
rtalloc1(const struct sockaddr *dst, int report)
{
        struct rtentry *rt;

        RT_RLOCK();
        rt = rtalloc1_locked(dst, report, true, false);
        RT_UNLOCK();

        return rt;
}

static void
rt_ref(struct rtentry *rt)
{

        KASSERTMSG(rt->rt_refcnt >= 0, "rt_refcnt=%d", rt->rt_refcnt);
        atomic_inc_uint(&rt->rt_refcnt);
}

void
rt_unref(struct rtentry *rt)
{

        KASSERT(rt != NULL);
        KASSERTMSG(rt->rt_refcnt > 0, "refcnt=%d", rt->rt_refcnt);

        atomic_dec_uint(&rt->rt_refcnt);
        if (!ISSET(rt->rt_flags, RTF_UP) || ISSET(rt->rt_flags, RTF_UPDATING)) {
                mutex_enter(&rt_free_global.lock);
                cv_broadcast(&rt->rt_cv);
                mutex_exit(&rt_free_global.lock);
        }
}

static bool
rt_wait_ok(void)
{

        /*
         * This originally returned !cpu_softintr_p(), but that doesn't
         * work: the caller may hold a lock (probably softnet lock)
         * that a softint is waiting for, in which case waiting here
         * would cause a deadlock.  See https://gnats.netbsd.org/56844
         * for details.  For now, until the locking paths are sorted
         * out, we just disable the waiting option altogether and
         * always defer to workqueue.
         */
        KASSERT(!cpu_intr_p());
        return false;
}

void
rt_wait_refcnt(const char *title, struct rtentry *rt, int cnt)
{
        mutex_enter(&rt_free_global.lock);
        while (rt->rt_refcnt > cnt) {
                dlog(LOG_DEBUG, "%s: %s waiting (refcnt=%d)\n",
                    __func__, title, rt->rt_refcnt);
                cv_wait(&rt->rt_cv, &rt_free_global.lock);
                dlog(LOG_DEBUG, "%s: %s waited (refcnt=%d)\n",
                    __func__, title, rt->rt_refcnt);
        }
        mutex_exit(&rt_free_global.lock);
}

void
rt_wait_psref(struct rtentry *rt)
{

        psref_target_destroy(&rt->rt_psref, rt_psref_class);
        psref_target_init(&rt->rt_psref, rt_psref_class);
}

static void
_rt_free(struct rtentry *rt)
{
        struct ifaddr *ifa;

        /*
         * Need to avoid a deadlock on rt_wait_refcnt of update
         * and a conflict on psref_target_destroy of update.
         */
#ifdef NET_MPSAFE
        rt_update_wait();
#endif

        RT_REFCNT_TRACE(rt);
        KASSERTMSG(rt->rt_refcnt >= 0, "refcnt=%d", rt->rt_refcnt);
        rt_wait_refcnt("free", rt, 0);
#ifdef NET_MPSAFE
        psref_target_destroy(&rt->rt_psref, rt_psref_class);
#endif

        rt_assert_inactive(rt);
        rttrash--;
        ifa = rt->rt_ifa;
        rt->rt_ifa = NULL;
        ifafree(ifa);
        rt->rt_ifp = NULL;
        cv_destroy(&rt->rt_cv);
        rt_destroy(rt);
        pool_put(&rtentry_pool, rt);
}

static void
rt_free_work(struct work *wk, void *arg)
{

        for (;;) {
                struct rtentry *rt;

                mutex_enter(&rt_free_global.lock);
                if ((rt = SLIST_FIRST(&rt_free_global.queue)) == NULL) {
                        rt_free_global.enqueued = false;
                        mutex_exit(&rt_free_global.lock);
                        return;
                }
                SLIST_REMOVE_HEAD(&rt_free_global.queue, rt_free);
                mutex_exit(&rt_free_global.lock);
                atomic_dec_uint(&rt->rt_refcnt);
                _rt_free(rt);
        }
}

void
rt_free(struct rtentry *rt)
{

        KASSERTMSG(rt->rt_refcnt > 0, "rt_refcnt=%d", rt->rt_refcnt);
        if (rt_wait_ok()) {
                atomic_dec_uint(&rt->rt_refcnt);
                _rt_free(rt);
                return;
        }

        mutex_enter(&rt_free_global.lock);
        /* No need to add a reference here. */
        SLIST_INSERT_HEAD(&rt_free_global.queue, rt, rt_free);
        if (!rt_free_global.enqueued) {
                workqueue_enqueue(rt_free_global.wq, &rt_free_global.wk, NULL);
                rt_free_global.enqueued = true;
        }
        mutex_exit(&rt_free_global.lock);
}

#ifdef NET_MPSAFE
static void
rt_update_wait(void)
{

        mutex_enter(&rt_update_global.lock);
        while (rt_update_global.ongoing) {
                dlog(LOG_DEBUG, "%s: waiting lwp=%p\n", __func__, curlwp);
                cv_wait(&rt_update_global.cv, &rt_update_global.lock);
                dlog(LOG_DEBUG, "%s: waited lwp=%p\n", __func__, curlwp);
        }
        mutex_exit(&rt_update_global.lock);
}
#endif

int
rt_update_prepare(struct rtentry *rt)
{

        dlog(LOG_DEBUG, "%s: updating rt=%p lwp=%p\n", __func__, rt, curlwp);

        RT_WLOCK();
        /* If the entry is being destroyed, don't proceed the update. */
        if (!ISSET(rt->rt_flags, RTF_UP)) {
                RT_UNLOCK();
                return ESRCH;
        }
        rt->rt_flags |= RTF_UPDATING;
        RT_UNLOCK();

        mutex_enter(&rt_update_global.lock);
        while (rt_update_global.ongoing) {
                dlog(LOG_DEBUG, "%s: waiting ongoing updating rt=%p lwp=%p\n",
                    __func__, rt, curlwp);
                cv_wait(&rt_update_global.cv, &rt_update_global.lock);
                dlog(LOG_DEBUG, "%s: waited ongoing updating rt=%p lwp=%p\n",
                    __func__, rt, curlwp);
        }
        rt_update_global.ongoing = true;
        /* XXX need it to avoid rt_update_wait by updater itself. */
        rt_update_global.lwp = curlwp;
        mutex_exit(&rt_update_global.lock);

        rt_wait_refcnt("update", rt, 1);
        rt_wait_psref(rt);

        return 0;
}

void
rt_update_finish(struct rtentry *rt)
{

        RT_WLOCK();
        rt->rt_flags &= ~RTF_UPDATING;
        RT_UNLOCK();

        mutex_enter(&rt_update_global.lock);
        rt_update_global.ongoing = false;
        rt_update_global.lwp = NULL;
        cv_broadcast(&rt_update_global.cv);
        mutex_exit(&rt_update_global.lock);

        dlog(LOG_DEBUG, "%s: updated rt=%p lwp=%p\n", __func__, rt, curlwp);
}

/*
 * Force a routing table entry to the specified
 * destination to go through the given gateway.
 * Normally called as a result of a routing redirect
 * message from the network layer.
 *
 * N.B.: must be called at splsoftnet
 */
void
rtredirect(const struct sockaddr *dst, const struct sockaddr *gateway,
        const struct sockaddr *netmask, int flags, const struct sockaddr *src,
        struct rtentry **rtp)
{
        struct rtentry *rt;
        int error = 0;
        uint64_t *stat = NULL;
        struct rt_addrinfo info;
        struct ifaddr *ifa;
        struct psref psref;

        /* verify the gateway is directly reachable */
        if ((ifa = ifa_ifwithnet_psref(gateway, &psref)) == NULL) {
                error = ENETUNREACH;
                goto out;
        }
        rt = rtalloc1(dst, 0);
        /*
         * If the redirect isn't from our current router for this dst,
         * it's either old or wrong.  If it redirects us to ourselves,
         * we have a routing loop, perhaps as a result of an interface
         * going down recently.
         */
        if (!(flags & RTF_DONE) && rt &&
             (sockaddr_cmp(src, rt->rt_gateway) != 0 || rt->rt_ifa != ifa))
                error = EINVAL;
        else {
                int s = pserialize_read_enter();
                struct ifaddr *_ifa;

                _ifa = ifa_ifwithaddr(gateway);
                if (_ifa != NULL)
                        error = EHOSTUNREACH;
                pserialize_read_exit(s);
        }
        if (error)
                goto done;
        /*
         * Create a new entry if we just got back a wildcard entry
         * or the lookup failed.  This is necessary for hosts
         * which use routing redirects generated by smart gateways
         * to dynamically build the routing tables.
         */
        if (rt == NULL || (rt_mask(rt) && rt_mask(rt)->sa_len < 2))
                goto create;
        /*
         * Don't listen to the redirect if it's
         * for a route to an interface.
         */
        if (rt->rt_flags & RTF_GATEWAY) {
                if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
                        /*
                         * Changing from route to net => route to host.
                         * Create new route, rather than smashing route to net.
                         */
                create:
                        if (rt != NULL)
                                rt_unref(rt);
                        flags |=  RTF_GATEWAY | RTF_DYNAMIC;
                        memset(&info, 0, sizeof(info));
                        info.rti_info[RTAX_DST] = dst;
                        info.rti_info[RTAX_GATEWAY] = gateway;
                        info.rti_info[RTAX_NETMASK] = netmask;
                        info.rti_ifa = ifa;
                        info.rti_flags = flags;
                        rt = NULL;
                        error = rtrequest1(RTM_ADD, &info, &rt);
                        if (rt != NULL)
                                flags = rt->rt_flags;
                        if (error == 0)
                                rt_newmsg_dynamic(RTM_ADD, rt);
                        stat = &rtstat.rts_dynamic;
                } else {
                        /*
                         * Smash the current notion of the gateway to
                         * this destination.  Should check about netmask!!!
                         */
#ifdef NET_MPSAFE
                        KASSERT(!cpu_softintr_p());

                        error = rt_update_prepare(rt);
                        if (error == 0) {
#endif
                                RT_WLOCK();
                                error = rt_setgate(rt, gateway);
                                if (error == 0) {
                                        rt->rt_flags |= RTF_MODIFIED;
                                        flags |= RTF_MODIFIED;
                                }
                                RT_UNLOCK();
#ifdef NET_MPSAFE
                                rt_update_finish(rt);
                        } else {
                                /*
                                 * If error != 0, the rtentry is being
                                 * destroyed, so doing nothing doesn't
                                 * matter.
                                 */
                        }
#endif
                        stat = &rtstat.rts_newgateway;
                }
        } else
                error = EHOSTUNREACH;
done:
        if (rt) {
                if (rtp != NULL && !error)
                        *rtp = rt;
                else
                        rt_unref(rt);
        }
out:
        if (error)
                rtstat.rts_badredirect++;
        else if (stat != NULL)
                (*stat)++;
        memset(&info, 0, sizeof(info));
        info.rti_info[RTAX_DST] = dst;
        info.rti_info[RTAX_GATEWAY] = gateway;
        info.rti_info[RTAX_NETMASK] = netmask;
        info.rti_info[RTAX_AUTHOR] = src;
        rt_missmsg(RTM_REDIRECT, &info, flags, error);
        ifa_release(ifa, &psref);
}

/*
 * Delete a route and generate a message.
 * It doesn't free a passed rt.
 */
static int
rtdeletemsg(struct rtentry *rt)
{
        int error;
        struct rt_addrinfo info;
        struct rtentry *retrt;

        /*
         * Request the new route so that the entry is not actually
         * deleted.  That will allow the information being reported to
         * be accurate (and consistent with route_output()).
         */
        memset(&info, 0, sizeof(info));
        info.rti_info[RTAX_DST] = rt_getkey(rt);
        info.rti_info[RTAX_NETMASK] = rt_mask(rt);
        info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
        info.rti_flags = rt->rt_flags;
        error = rtrequest1(RTM_DELETE, &info, &retrt);

        rt_missmsg(RTM_DELETE, &info, info.rti_flags, error);

        return error;
}

static struct ifaddr *
ifa_ifwithroute_psref(int flags, const struct sockaddr *dst,
    const struct sockaddr *gateway, struct psref *psref)
{
        struct ifaddr *ifa = NULL;

        if ((flags & RTF_GATEWAY) == 0) {
                /*
                 * If we are adding a route to an interface,
                 * and the interface is a pt to pt link
                 * we should search for the destination
                 * as our clue to the interface.  Otherwise
                 * we can use the local address.
                 */
                if ((flags & RTF_HOST) && gateway->sa_family != AF_LINK)
                        ifa = ifa_ifwithdstaddr_psref(dst, psref);
                if (ifa == NULL)
                        ifa = ifa_ifwithaddr_psref(gateway, psref);
        } else {
                /*
                 * If we are adding a route to a remote net
                 * or host, the gateway may still be on the
                 * other end of a pt to pt link.
                 */
                ifa = ifa_ifwithdstaddr_psref(gateway, psref);
        }
        if (ifa == NULL)
                ifa = ifa_ifwithnet_psref(gateway, psref);
        if (ifa == NULL) {
                int s;
                struct rtentry *rt;

                rt = rtalloc1_locked(gateway, 0, true, true);
                if (rt == NULL)
                        return NULL;
                if (rt->rt_flags & RTF_GATEWAY) {
                        rt_unref(rt);
                        return NULL;
                }
                /*
                 * Just in case. May not need to do this workaround.
                 * Revisit when working on rtentry MP-ification.
                 */
                s = pserialize_read_enter();
                IFADDR_READER_FOREACH(ifa, rt->rt_ifp) {
                        if (ifa == rt->rt_ifa)
                                break;
                }
                if (ifa != NULL)
                        ifa_acquire(ifa, psref);
                pserialize_read_exit(s);
                rt_unref(rt);
                if (ifa == NULL)
                        return NULL;
        }
        if (ifa->ifa_addr->sa_family != dst->sa_family) {
                struct ifaddr *nifa;
                int s;

                s = pserialize_read_enter();
                nifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
                if (nifa != NULL) {
                        ifa_release(ifa, psref);
                        ifa_acquire(nifa, psref);
                        ifa = nifa;
                }
                pserialize_read_exit(s);
        }
        return ifa;
}

/*
 * If it suceeds and ret_nrt isn't NULL, refcnt of ret_nrt is incremented.
 * The caller has to rtfree it by itself.
 */
int
rtrequest(int req, const struct sockaddr *dst, const struct sockaddr *gateway,
        const struct sockaddr *netmask, int flags, struct rtentry **ret_nrt)
{
        struct rt_addrinfo info;

        memset(&info, 0, sizeof(info));
        info.rti_flags = flags;
        info.rti_info[RTAX_DST] = dst;
        info.rti_info[RTAX_GATEWAY] = gateway;
        info.rti_info[RTAX_NETMASK] = netmask;
        return rtrequest1(req, &info, ret_nrt);
}

static struct ifnet *
rt_getifp(struct rt_addrinfo *info, struct psref *psref)
{
        const struct sockaddr *ifpaddr = info->rti_info[RTAX_IFP];

        if (info->rti_ifp != NULL)
                return NULL;
        /*
         * ifp may be specified by sockaddr_dl when protocol address
         * is ambiguous
         */
        if (ifpaddr != NULL && ifpaddr->sa_family == AF_LINK) {
                struct ifaddr *ifa;
                int s = pserialize_read_enter();

                ifa = ifa_ifwithnet(ifpaddr);
                if (ifa != NULL)
                        info->rti_ifp = if_get_byindex(ifa->ifa_ifp->if_index,
                            psref);
                pserialize_read_exit(s);
        }

        return info->rti_ifp;
}

static struct ifaddr *
rt_getifa(struct rt_addrinfo *info, struct psref *psref)
{
        struct ifaddr *ifa = NULL;
        const struct sockaddr *dst = info->rti_info[RTAX_DST];
        const struct sockaddr *gateway = info->rti_info[RTAX_GATEWAY];
        const struct sockaddr *ifaaddr = info->rti_info[RTAX_IFA];
        int flags = info->rti_flags;
        const struct sockaddr *sa;

        if (info->rti_ifa == NULL && ifaaddr != NULL) {
                ifa = ifa_ifwithaddr_psref(ifaaddr, psref);
                if (ifa != NULL)
                        goto got;
        }

        sa = ifaaddr != NULL ? ifaaddr :
            (gateway != NULL ? gateway : dst);
        if (sa != NULL && info->rti_ifp != NULL)
                ifa = ifaof_ifpforaddr_psref(sa, info->rti_ifp, psref);
        else if (dst != NULL && gateway != NULL)
                ifa = ifa_ifwithroute_psref(flags, dst, gateway, psref);
        else if (sa != NULL)
                ifa = ifa_ifwithroute_psref(flags, sa, sa, psref);
        if (ifa == NULL)
                return NULL;
got:
        if (ifa->ifa_getifa != NULL) {
                /* FIXME ifa_getifa is NOMPSAFE */
                ifa = (*ifa->ifa_getifa)(ifa, dst);
                if (ifa == NULL)
                        return NULL;
                ifa_acquire(ifa, psref);
        }
        info->rti_ifa = ifa;
        if (info->rti_ifp == NULL)
                info->rti_ifp = ifa->ifa_ifp;
        return ifa;
}

/*
 * If it suceeds and ret_nrt isn't NULL, refcnt of ret_nrt is incremented.
 * The caller has to rtfree it by itself.
 */
int
rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
{
        int s = splsoftnet(), ss;
        int error = 0, rc;
        struct rtentry *rt;
        rtbl_t *rtbl;
        struct ifaddr *ifa = NULL;
        struct sockaddr_storage maskeddst;
        const struct sockaddr *dst = info->rti_info[RTAX_DST];
        const struct sockaddr *gateway = info->rti_info[RTAX_GATEWAY];
        const struct sockaddr *netmask = info->rti_info[RTAX_NETMASK];
        int flags = info->rti_flags;
        struct psref psref_ifp, psref_ifa;
        int bound = 0;
        struct ifnet *ifp = NULL;
        bool need_to_release_ifa = true;
        bool need_unlock = true;
#define senderr(x) { error = x ; goto bad; }

        RT_WLOCK();

        bound = curlwp_bind();
        if ((rtbl = rt_gettable(dst->sa_family)) == NULL)
                senderr(ESRCH);
        if (flags & RTF_HOST)
                netmask = NULL;
        switch (req) {
        case RTM_DELETE:
                if (netmask) {
                        rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
                            netmask);
                        dst = (struct sockaddr *)&maskeddst;
                }
                if ((rt = rt_lookup(rtbl, dst, netmask)) == NULL)
                        senderr(ESRCH);
                if ((rt = rt_deladdr(rtbl, dst, netmask)) == NULL)
                        senderr(ESRCH);
                rt->rt_flags &= ~RTF_UP;
                ifa = rt->rt_ifa;
                if (ifa->ifa_flags & IFA_ROUTE &&
                    rt_ifa_connected(rt, ifa)) {
                        RT_DPRINTF("rt->_rt_key = %p, ifa = %p, "
                            "deleted IFA_ROUTE\n",
                            (void *)rt->_rt_key, (void *)ifa);
                        ifa->ifa_flags &= ~IFA_ROUTE;
                }
                if (ifa->ifa_rtrequest)
                        ifa->ifa_rtrequest(RTM_DELETE, rt, info);
                ifa = NULL;
                rttrash++;
                if (ret_nrt) {
                        *ret_nrt = rt;
                        rt_ref(rt);
                        RT_REFCNT_TRACE(rt);
                }
                rtcache_invalidate();
                RT_UNLOCK();
                need_unlock = false;
                rt_timer_remove_all(rt);
#if defined(INET) || defined(INET6)
                if (netmask != NULL)
                        lltable_prefix_free(dst->sa_family, dst, netmask, 0);
#endif
                if (ret_nrt == NULL) {
                        /* Adjust the refcount */
                        rt_ref(rt);
                        RT_REFCNT_TRACE(rt);
                        rt_free(rt);
                }
                break;

        case RTM_ADD:
                if (info->rti_ifa == NULL) {
                        ifp = rt_getifp(info, &psref_ifp);
                        ifa = rt_getifa(info, &psref_ifa);
                        if (ifa == NULL)
                                senderr(ENETUNREACH);
                } else {
                        /* Caller should have a reference of ifa */
                        ifa = info->rti_ifa;
                        need_to_release_ifa = false;
                }
                rt = pool_get(&rtentry_pool, PR_NOWAIT);
                if (rt == NULL)
                        senderr(ENOBUFS);
                memset(rt, 0, sizeof(*rt));
                rt->rt_flags = RTF_UP | (flags & ~RTF_DONTCHANGEIFA);
                LIST_INIT(&rt->rt_timer);

                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                if (netmask) {
                        rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
                            netmask);
                        rt_setkey(rt, (struct sockaddr *)&maskeddst, M_NOWAIT);
                } else {
                        rt_setkey(rt, dst, M_NOWAIT);
                }
                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                if (rt_getkey(rt) == NULL ||
                    rt_setgate(rt, gateway) != 0) {
                        pool_put(&rtentry_pool, rt);
                        senderr(ENOBUFS);
                }

                rt_set_ifa(rt, ifa);
                if (info->rti_info[RTAX_TAG] != NULL) {
                        const struct sockaddr *tag;
                        tag = rt_settag(rt, info->rti_info[RTAX_TAG]);
                        if (tag == NULL)
                                senderr(ENOBUFS);
                }
                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);

                ss = pserialize_read_enter();
                if (info->rti_info[RTAX_IFP] != NULL) {
                        struct ifaddr *ifa2;
                        ifa2 = ifa_ifwithnet(info->rti_info[RTAX_IFP]);
                        if (ifa2 != NULL)
                                rt->rt_ifp = ifa2->ifa_ifp;
                        else
                                rt->rt_ifp = ifa->ifa_ifp;
                } else
                        rt->rt_ifp = ifa->ifa_ifp;
                pserialize_read_exit(ss);
                cv_init(&rt->rt_cv, "rtentry");
                psref_target_init(&rt->rt_psref, rt_psref_class);
                if (ifa->ifa_rtrequest)
                        ifa->ifa_rtrequest(req, rt, info);

                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                rc = rt_addaddr(rtbl, rt, netmask);
                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                if (rc != 0) {
                        ifafree(ifa); /* for rt_set_ifa above */
                        cv_destroy(&rt->rt_cv);
                        rt_destroy(rt);
                        pool_put(&rtentry_pool, rt);
                        senderr(rc);
                }
                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                if (need_to_release_ifa)
                        ifa_release(ifa, &psref_ifa);
                ifa = NULL;
                if_put(ifp, &psref_ifp);
                ifp = NULL;
                RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
                if (ret_nrt) {
                        *ret_nrt = rt;
                        rt_ref(rt);
                        RT_REFCNT_TRACE(rt);
                }
                rtcache_invalidate();
                RT_UNLOCK();
                need_unlock = false;
                break;
        case RTM_GET:
                if (netmask != NULL) {
                        rt_maskedcopy(dst, (struct sockaddr *)&maskeddst,
                            netmask);
                        dst = (struct sockaddr *)&maskeddst;
                }
                if ((rt = rt_lookup(rtbl, dst, netmask)) == NULL)
                        senderr(ESRCH);
                if (ret_nrt != NULL) {
                        *ret_nrt = rt;
                        rt_ref(rt);
                        RT_REFCNT_TRACE(rt);
                }
                break;
        }
bad:
        if (need_to_release_ifa)
                ifa_release(ifa, &psref_ifa);
        if_put(ifp, &psref_ifp);
        curlwp_bindx(bound);
        if (need_unlock)
                RT_UNLOCK();
        splx(s);
        return error;
}

int
rt_setgate(struct rtentry *rt, const struct sockaddr *gate)
{
        struct sockaddr *new, *old;

        KASSERT(RT_WLOCKED());
        KASSERT(rt->_rt_key != NULL);
        RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);

        new = sockaddr_dup(gate, M_ZERO | M_NOWAIT);
        if (new == NULL)
                return ENOMEM;

        old = rt->rt_gateway;
        rt->rt_gateway = new;
        if (old != NULL)
                sockaddr_free(old);

        KASSERT(rt->_rt_key != NULL);
        RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);

        if (rt->rt_flags & RTF_GATEWAY) {
                struct rtentry *gwrt;

                gwrt = rtalloc1_locked(gate, 1, false, true);
                /*
                 * If we switched gateways, grab the MTU from the new
                 * gateway route if the current MTU, if the current MTU is
                 * greater than the MTU of gateway.
                 * Note that, if the MTU of gateway is 0, we will reset the
                 * MTU of the route to run PMTUD again from scratch. XXX
                 */
                if (gwrt != NULL) {
                        KASSERT(gwrt->_rt_key != NULL);
                        RT_DPRINTF("gwrt->_rt_key = %p\n", gwrt->_rt_key);
                        if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
                            rt->rt_rmx.rmx_mtu &&
                            rt->rt_rmx.rmx_mtu > gwrt->rt_rmx.rmx_mtu) {
                                rt->rt_rmx.rmx_mtu = gwrt->rt_rmx.rmx_mtu;
                        }
                        rt_unref(gwrt);
                }
        }
        KASSERT(rt->_rt_key != NULL);
        RT_DPRINTF("rt->_rt_key = %p\n", (void *)rt->_rt_key);
        return 0;
}

static struct ifaddr *
rt_update_get_ifa(const struct rt_addrinfo *info, const struct rtentry *rt,
    struct ifnet **ifp, struct psref *psref_ifp, struct psref *psref)
{
        struct ifaddr *ifa = NULL;

        *ifp = NULL;
        if (info->rti_info[RTAX_IFP] != NULL) {
                ifa = ifa_ifwithnet_psref(info->rti_info[RTAX_IFP], psref);
                if (ifa == NULL)
                        goto next;
                if (ifa->ifa_ifp->if_flags & IFF_UNNUMBERED) {
                        ifa_release(ifa, psref);
                        ifa = NULL;
                        goto next;
                }
                *ifp = ifa->ifa_ifp;
                if_acquire(*ifp, psref_ifp);
                if (info->rti_info[RTAX_IFA] == NULL &&
                    info->rti_info[RTAX_GATEWAY] == NULL)
                        goto out;
                ifa_release(ifa, psref);
                if (info->rti_info[RTAX_IFA] == NULL) {
                        /* route change <dst> <gw> -ifp <if> */
                        ifa = ifaof_ifpforaddr_psref(
                            info->rti_info[RTAX_GATEWAY], *ifp, psref);
                } else {
                        /* route change <dst> -ifp <if> -ifa <addr> */
                        ifa = ifa_ifwithaddr_psref(info->rti_info[RTAX_IFA],
                            psref);
                        if (ifa != NULL)
                                goto out;
                        ifa = ifaof_ifpforaddr_psref(info->rti_info[RTAX_IFA],
                            *ifp, psref);
                }
                goto out;
        }
next:
        if (info->rti_info[RTAX_IFA] != NULL) {
                /* route change <dst> <gw> -ifa <addr> */
                ifa = ifa_ifwithaddr_psref(info->rti_info[RTAX_IFA], psref);
                if (ifa != NULL)
                        goto out;
        }
        if (info->rti_info[RTAX_GATEWAY] != NULL) {
                /* route change <dst> <gw> */
                ifa = ifa_ifwithroute_psref(rt->rt_flags, rt_getkey(rt),
                    info->rti_info[RTAX_GATEWAY], psref);
        }
out:
        if (ifa != NULL && *ifp == NULL) {
                *ifp = ifa->ifa_ifp;
                if_acquire(*ifp, psref_ifp);
        }
        if (ifa == NULL && *ifp != NULL) {
                if_put(*ifp, psref_ifp);
                *ifp = NULL;
        }
        return ifa;
}

int
rt_update(struct rtentry *rt, struct rt_addrinfo *info, void *rtm)
{
        int error = 0;
        struct ifnet *ifp = NULL, *new_ifp = NULL;
        struct ifaddr *ifa = NULL, *new_ifa;
        struct psref psref_ifa, psref_new_ifa, psref_ifp, psref_new_ifp;
        bool newgw, ifp_changed = false;

        RT_WLOCK();
        /*
         * New gateway could require new ifaddr, ifp;
         * flags may also be different; ifp may be specified
         * by ll sockaddr when protocol address is ambiguous
         */
        newgw = info->rti_info[RTAX_GATEWAY] != NULL &&
            sockaddr_cmp(info->rti_info[RTAX_GATEWAY], rt->rt_gateway) != 0;

        if (newgw || info->rti_info[RTAX_IFP] != NULL ||
            info->rti_info[RTAX_IFA] != NULL) {
                ifp = rt_getifp(info, &psref_ifp);
                /* info refers ifp so we need to keep a reference */
                ifa = rt_getifa(info, &psref_ifa);
                if (ifa == NULL) {
                        error = ENETUNREACH;
                        goto out;
                }
        }
        if (newgw) {
                error = rt_setgate(rt, info->rti_info[RTAX_GATEWAY]);
                if (error != 0)
                        goto out;
        }
        if (info->rti_info[RTAX_TAG]) {
                const struct sockaddr *tag;
                tag = rt_settag(rt, info->rti_info[RTAX_TAG]);
                if (tag == NULL) {
                        error = ENOBUFS;
                        goto out;
                }
        }
        /*
         * New gateway could require new ifaddr, ifp;
         * flags may also be different; ifp may be specified
         * by ll sockaddr when protocol address is ambiguous
         */
        new_ifa = rt_update_get_ifa(info, rt, &new_ifp, &psref_new_ifp,
            &psref_new_ifa);
        if (new_ifa != NULL) {
                ifa_release(ifa, &psref_ifa);
                ifa = new_ifa;
        }
        if (ifa) {
                struct ifaddr *oifa = rt->rt_ifa;
                if (oifa != ifa && !ifa_is_destroying(ifa) &&
                    new_ifp != NULL && !if_is_deactivated(new_ifp)) {
                        if (oifa && oifa->ifa_rtrequest)
                                oifa->ifa_rtrequest(RTM_DELETE, rt, info);
                        rt_replace_ifa(rt, ifa);
                        rt->rt_ifp = new_ifp;
                        ifp_changed = true;
                }
                if (new_ifa == NULL)
                        ifa_release(ifa, &psref_ifa);
                /* To avoid ifa_release below */
                ifa = NULL;
        }
        ifa_release(new_ifa, &psref_new_ifa);
        if (new_ifp && rt->rt_ifp != new_ifp && !if_is_deactivated(new_ifp)) {
                rt->rt_ifp = new_ifp;
                ifp_changed = true;
        }
        rt_setmetrics(rtm, rt);
        if (rt->rt_flags != info->rti_flags) {
                rt->rt_flags = (info->rti_flags & ~PRESERVED_RTF) |
                    (rt->rt_flags & PRESERVED_RTF);
        }
        if (rt->rt_ifa->ifa_rtrequest)
                rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, info);
#if defined(INET) || defined(INET6)
        if (ifp_changed && rt_mask(rt) != NULL)
                lltable_prefix_free(rt_getkey(rt)->sa_family, rt_getkey(rt),
                    rt_mask(rt), 0);
#else
        (void)ifp_changed; /* XXX gcc */
#endif
out:
        ifa_release(ifa, &psref_ifa);
        if_put(new_ifp, &psref_new_ifp);
        if_put(ifp, &psref_ifp);

        RT_UNLOCK();

        return error;
}

static void
rt_maskedcopy(const struct sockaddr *src, struct sockaddr *dst,
        const struct sockaddr *netmask)
{
        const char *netmaskp = &netmask->sa_data[0],
                   *srcp = &src->sa_data[0];
        char *dstp = &dst->sa_data[0];
        const char *maskend = (char *)dst + MIN(netmask->sa_len, src->sa_len);
        const char *srcend = (char *)dst + src->sa_len;

        dst->sa_len = src->sa_len;
        dst->sa_family = src->sa_family;

        while (dstp < maskend)
                *dstp++ = *srcp++ & *netmaskp++;
        if (dstp < srcend)
                memset(dstp, 0, (size_t)(srcend - dstp));
}

/*
 * Inform the routing socket of a route change.
 */
void
rt_newmsg(const int cmd, const struct rtentry *rt)
{
        struct rt_addrinfo info;

        memset((void *)&info, 0, sizeof(info));
        info.rti_info[RTAX_DST] = rt_getkey(rt);
        info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
        info.rti_info[RTAX_NETMASK] = rt_mask(rt);
        if (rt->rt_ifp) {
                info.rti_info[RTAX_IFP] = rt->rt_ifp->if_dl->ifa_addr;
                info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
        }

        rt_missmsg(cmd, &info, rt->rt_flags, 0);
}

/*
 * Inform the routing socket of a route change for RTF_DYNAMIC.
 */
void
rt_newmsg_dynamic(const int cmd, const struct rtentry *rt)
{
        struct rt_addrinfo info;
        struct sockaddr *gateway = rt->rt_gateway;

        if (gateway == NULL)
                return;

        switch(gateway->sa_family) {
#ifdef INET
        case AF_INET: {
                extern bool icmp_dynamic_rt_msg;
                if (!icmp_dynamic_rt_msg)
                        return;
                break;
        }
#endif
#ifdef INET6
        case AF_INET6: {
                extern bool icmp6_dynamic_rt_msg;
                if (!icmp6_dynamic_rt_msg)
                        return;
                break;
        }
#endif
        default:
                return;
        }

        memset((void *)&info, 0, sizeof(info));
        info.rti_info[RTAX_DST] = rt_getkey(rt);
        info.rti_info[RTAX_GATEWAY] = gateway;
        info.rti_info[RTAX_NETMASK] = rt_mask(rt);
        if (rt->rt_ifp) {
                info.rti_info[RTAX_IFP] = rt->rt_ifp->if_dl->ifa_addr;
                info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
        }

        rt_missmsg(cmd, &info, rt->rt_flags, 0);
}

/*
 * Set up or tear down a routing table entry, normally
 * for an interface.
 */
int
rtinit(struct ifaddr *ifa, int cmd, int flags)
{
        struct rtentry *rt;
        struct sockaddr *dst, *odst;
        struct sockaddr_storage maskeddst;
        struct rtentry *nrt = NULL;
        int error;
        struct rt_addrinfo info;

        dst = flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
        if (cmd == RTM_DELETE) {
                if ((flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
                        /* Delete subnet route for this interface */
                        odst = dst;
                        dst = (struct sockaddr *)&maskeddst;
                        rt_maskedcopy(odst, dst, ifa->ifa_netmask);
                }
                if ((rt = rtalloc1(dst, 0)) != NULL) {
                        if (rt->rt_ifa != ifa) {
                                rt_unref(rt);
                                return (flags & RTF_HOST) ? EHOSTUNREACH
                                                        : ENETUNREACH;
                        }
                        rt_unref(rt);
                }
        }
        memset(&info, 0, sizeof(info));
        info.rti_ifa = ifa;
        info.rti_flags = flags | ifa->ifa_flags | RTF_DONTCHANGEIFA;
        info.rti_info[RTAX_DST] = dst;
        info.rti_info[RTAX_GATEWAY] = ifa->ifa_addr;

        /*
         * XXX here, it seems that we are assuming that ifa_netmask is NULL
         * for RTF_HOST.  bsdi4 passes NULL explicitly (via intermediate
         * variable) when RTF_HOST is 1.  still not sure if i can safely
         * change it to meet bsdi4 behavior.
         */
        if (cmd != RTM_LLINFO_UPD)
                info.rti_info[RTAX_NETMASK] = ifa->ifa_netmask;
        error = rtrequest1((cmd == RTM_LLINFO_UPD) ? RTM_GET : cmd, &info,
            &nrt);
        if (error != 0)
                return error;

        rt = nrt;
        RT_REFCNT_TRACE(rt);
        switch (cmd) {
        case RTM_DELETE:
                rt_newmsg(cmd, rt);
                rt_free(rt);
                break;
        case RTM_LLINFO_UPD:
                if (cmd == RTM_LLINFO_UPD && ifa->ifa_rtrequest != NULL)
                        ifa->ifa_rtrequest(RTM_LLINFO_UPD, rt, &info);
                rt_newmsg(RTM_CHANGE, rt);
                rt_unref(rt);
                break;
        case RTM_ADD:
                KASSERT(rt->rt_ifa == ifa);
                rt_newmsg(cmd, rt);
                rt_unref(rt);
                RT_REFCNT_TRACE(rt);
                break;
        }
        return error;
}

/*
 * Create a local route entry for the address.
 * Announce the addition of the address and the route to the routing socket.
 */
int
rt_ifa_addlocal(struct ifaddr *ifa)
{
        struct rtentry *rt;
        int e;

        /* If there is no loopback entry, allocate one. */
        rt = rtalloc1(ifa->ifa_addr, 0);
#ifdef RT_DEBUG
        if (rt != NULL)
                dump_rt(rt);
#endif
        if (rt == NULL || (rt->rt_flags & RTF_HOST) == 0 ||
            (rt->rt_ifp->if_flags & IFF_LOOPBACK) == 0)
        {
                struct rt_addrinfo info;
                struct rtentry *nrt;

                memset(&info, 0, sizeof(info));
                info.rti_flags = RTF_HOST | RTF_LOCAL | RTF_DONTCHANGEIFA;
                info.rti_info[RTAX_DST] = ifa->ifa_addr;
                info.rti_info[RTAX_GATEWAY] =
                    (const struct sockaddr *)ifa->ifa_ifp->if_sadl;
                info.rti_ifa = ifa;
                nrt = NULL;
                e = rtrequest1(RTM_ADD, &info, &nrt);
                rt_addrmsg_rt(RTM_ADD, ifa, e, nrt);
                if (nrt != NULL) {
                        KASSERT(nrt->rt_ifa == ifa);
#ifdef RT_DEBUG
                        dump_rt(nrt);
#endif
                        rt_unref(nrt);
                        RT_REFCNT_TRACE(nrt);
                }
        } else {
                e = 0;
                rt_addrmsg(RTM_NEWADDR, ifa);
        }
        if (rt != NULL)
                rt_unref(rt);
        return e;
}

/*
 * Remove the local route entry for the address.
 * Announce the removal of the address and the route to the routing socket.
 */
int
rt_ifa_remlocal(struct ifaddr *ifa, struct ifaddr *alt_ifa)
{
        struct rtentry *rt;
        int e = 0;

        rt = rtalloc1(ifa->ifa_addr, 0);

        /*
         * Before deleting, check if a corresponding loopbacked
         * host route surely exists.  With this check, we can avoid
         * deleting an interface direct route whose destination is
         * the same as the address being removed.  This can happen
         * when removing a subnet-router anycast address on an
         * interface attached to a shared medium.
         */
        if (rt != NULL &&
            (rt->rt_flags & RTF_HOST) &&
            (rt->rt_ifp->if_flags & IFF_LOOPBACK))
        {
                /* If we cannot replace the route's ifaddr with the equivalent
                 * ifaddr of another interface, I believe it is safest to
                 * delete the route.
                 */
                if (alt_ifa == NULL) {
                        e = rtdeletemsg(rt);
                        if (e == 0) {
                                rt_unref(rt);
                                rt_free(rt);
                                rt = NULL;
                        }
                        rt_addrmsg(RTM_DELADDR, ifa);
                } else {
#ifdef NET_MPSAFE
                        int error = rt_update_prepare(rt);
                        if (error == 0) {
                                rt_replace_ifa(rt, alt_ifa);
                                rt_update_finish(rt);
                        } else {
                                /*
                                 * If error != 0, the rtentry is being
                                 * destroyed, so doing nothing doesn't
                                 * matter.
                                 */
                        }
#else
                        rt_replace_ifa(rt, alt_ifa);
#endif
                        rt_newmsg(RTM_CHANGE, rt);
                }
        } else
                rt_addrmsg(RTM_DELADDR, ifa);
        if (rt != NULL)
                rt_unref(rt);
        return e;
}

/*
 * Route timer routines.  These routes allow functions to be called
 * for various routes at any time.  This is useful in supporting
 * path MTU discovery and redirect route deletion.
 *
 * This is similar to some BSDI internal functions, but it provides
 * for multiple queues for efficiency's sake...
 */

LIST_HEAD(, rttimer_queue) rttimer_queue_head;
static int rt_init_done = 0;

/*
 * Some subtle order problems with domain initialization mean that
 * we cannot count on this being run from rt_init before various
 * protocol initializations are done.  Therefore, we make sure
 * that this is run when the first queue is added...
 */

static void rt_timer_work(struct work *, void *);

static void
rt_timer_init(void)
{
        int error;

        assert(rt_init_done == 0);

        /* XXX should be in rt_init */
        rw_init(&rt_lock);

        LIST_INIT(&rttimer_queue_head);
        callout_init(&rt_timer_ch, CALLOUT_MPSAFE);
        error = workqueue_create(&rt_timer_wq, "rt_timer",
            rt_timer_work, NULL, PRI_USER, IPL_SOFTNET, RT_WQ_FLAGS);
        if (error)
                panic("%s: workqueue_create failed (%d)\n", __func__, error);
        callout_reset(&rt_timer_ch, hz, rt_timer_timer, NULL);
        rt_init_done = 1;
}

struct rttimer_queue *
rt_timer_queue_create(u_int timeout)
{
        struct rttimer_queue *rtq;

        if (rt_init_done == 0)
                rt_timer_init();

        R_Malloc(rtq, struct rttimer_queue *, sizeof *rtq);
        if (rtq == NULL)
                return NULL;
        memset(rtq, 0, sizeof(*rtq));

        rtq->rtq_timeout = timeout;
        TAILQ_INIT(&rtq->rtq_head);
        RT_WLOCK();
        LIST_INSERT_HEAD(&rttimer_queue_head, rtq, rtq_link);
        RT_UNLOCK();

        return rtq;
}

void
rt_timer_queue_change(struct rttimer_queue *rtq, long timeout)
{

        rtq->rtq_timeout = timeout;
}

static void
rt_timer_queue_remove_all(struct rttimer_queue *rtq)
{
        struct rttimer *r;

        RT_ASSERT_WLOCK();

        while ((r = TAILQ_FIRST(&rtq->rtq_head)) != NULL) {
                LIST_REMOVE(r, rtt_link);
                TAILQ_REMOVE(&rtq->rtq_head, r, rtt_next);
                rt_ref(r->rtt_rt); /* XXX */
                RT_REFCNT_TRACE(r->rtt_rt);
                RT_UNLOCK();
                (*r->rtt_func)(r->rtt_rt, r);
                pool_put(&rttimer_pool, r);
                RT_WLOCK();
                if (rtq->rtq_count > 0)
                        rtq->rtq_count--;
                else
                        printf("rt_timer_queue_remove_all: "
                            "rtq_count reached 0\n");
        }
}

void
rt_timer_queue_destroy(struct rttimer_queue *rtq)
{

        RT_WLOCK();
        rt_timer_queue_remove_all(rtq);
        LIST_REMOVE(rtq, rtq_link);
        RT_UNLOCK();

        /*
         * Caller is responsible for freeing the rttimer_queue structure.
         */
}

unsigned long
rt_timer_count(struct rttimer_queue *rtq)
{
        return rtq->rtq_count;
}

static void
rt_timer_remove_all(struct rtentry *rt)
{
        struct rttimer *r;

        RT_WLOCK();
        while ((r = LIST_FIRST(&rt->rt_timer)) != NULL) {
                LIST_REMOVE(r, rtt_link);
                TAILQ_REMOVE(&r->rtt_queue->rtq_head, r, rtt_next);
                if (r->rtt_queue->rtq_count > 0)
                        r->rtt_queue->rtq_count--;
                else
                        printf("rt_timer_remove_all: rtq_count reached 0\n");
                pool_put(&rttimer_pool, r);
        }
        RT_UNLOCK();
}

int
rt_timer_add(struct rtentry *rt,
        void (*func)(struct rtentry *, struct rttimer *),
        struct rttimer_queue *queue)
{
        struct rttimer *r;

        KASSERT(func != NULL);
        RT_WLOCK();
        /*
         * If there's already a timer with this action, destroy it before
         * we add a new one.
         */
        LIST_FOREACH(r, &rt->rt_timer, rtt_link) {
                if (r->rtt_func == func)
                        break;
        }
        if (r != NULL) {
                LIST_REMOVE(r, rtt_link);
                TAILQ_REMOVE(&r->rtt_queue->rtq_head, r, rtt_next);
                if (r->rtt_queue->rtq_count > 0)
                        r->rtt_queue->rtq_count--;
                else
                        printf("rt_timer_add: rtq_count reached 0\n");
        } else {
                r = pool_get(&rttimer_pool, PR_NOWAIT);
                if (r == NULL) {
                        RT_UNLOCK();
                        return ENOBUFS;
                }
        }

        memset(r, 0, sizeof(*r));

        r->rtt_rt = rt;
        r->rtt_time = time_uptime;
        r->rtt_func = func;
        r->rtt_queue = queue;
        LIST_INSERT_HEAD(&rt->rt_timer, r, rtt_link);
        TAILQ_INSERT_TAIL(&queue->rtq_head, r, rtt_next);
        r->rtt_queue->rtq_count++;

        RT_UNLOCK();

        return 0;
}

static void
rt_timer_work(struct work *wk, void *arg)
{
        struct rttimer_queue *rtq;
        struct rttimer *r;

        RT_WLOCK();
        LIST_FOREACH(rtq, &rttimer_queue_head, rtq_link) {
                while ((r = TAILQ_FIRST(&rtq->rtq_head)) != NULL &&
                    (r->rtt_time + rtq->rtq_timeout) < time_uptime) {
                        LIST_REMOVE(r, rtt_link);
                        TAILQ_REMOVE(&rtq->rtq_head, r, rtt_next);
                        /*
                         * Take a reference to avoid the rtentry is freed
                         * accidentally after RT_UNLOCK.  The callback
                         * (rtt_func) must rt_unref it by itself.
                         */
                        rt_ref(r->rtt_rt);
                        RT_REFCNT_TRACE(r->rtt_rt);
                        RT_UNLOCK();
                        (*r->rtt_func)(r->rtt_rt, r);
                        pool_put(&rttimer_pool, r);
                        RT_WLOCK();
                        if (rtq->rtq_count > 0)
                                rtq->rtq_count--;
                        else
                                printf("rt_timer_timer: rtq_count reached 0\n");
                }
        }
        RT_UNLOCK();

        callout_reset(&rt_timer_ch, hz, rt_timer_timer, NULL);
}

static void
rt_timer_timer(void *arg)
{

        workqueue_enqueue(rt_timer_wq, &rt_timer_wk, NULL);
}

static struct rtentry *
_rtcache_init(struct route *ro, int flag)
{
        struct rtentry *rt;

        rtcache_invariants(ro);
        KASSERT(ro->_ro_rt == NULL);

        if (rtcache_getdst(ro) == NULL)
                return NULL;
        rt = rtalloc1(rtcache_getdst(ro), flag);
        if (rt != NULL) {
                RT_RLOCK();
                if (ISSET(rt->rt_flags, RTF_UP)) {
                        ro->_ro_rt = rt;
                        ro->ro_rtcache_generation = rtcache_generation;
                        rtcache_ref(rt, ro);
                }
                RT_UNLOCK();
                rt_unref(rt);
        }

        rtcache_invariants(ro);
        return ro->_ro_rt;
}

struct rtentry *
rtcache_init(struct route *ro)
{

        return _rtcache_init(ro, 1);
}

struct rtentry *
rtcache_init_noclone(struct route *ro)
{

        return _rtcache_init(ro, 0);
}

struct rtentry *
rtcache_update(struct route *ro, int clone)
{

        ro->_ro_rt = NULL;
        return _rtcache_init(ro, clone);
}

void
rtcache_copy(struct route *new_ro, struct route *old_ro)
{
        struct rtentry *rt;
        int ret;

        KASSERT(new_ro != old_ro);
        rtcache_invariants(new_ro);
        rtcache_invariants(old_ro);

        rt = rtcache_validate(old_ro);

        if (rtcache_getdst(old_ro) == NULL)
                goto out;
        ret = rtcache_setdst(new_ro, rtcache_getdst(old_ro));
        if (ret != 0)
                goto out;

        RT_RLOCK();
        new_ro->_ro_rt = rt;
        new_ro->ro_rtcache_generation = rtcache_generation;
        RT_UNLOCK();
        rtcache_invariants(new_ro);
out:
        rtcache_unref(rt, old_ro);
        return;
}

#if defined(RT_DEBUG) && defined(NET_MPSAFE)
static void
rtcache_trace(const char *func, struct rtentry *rt, struct route *ro)
{
        char dst[64];

        sockaddr_format(ro->ro_sa, dst, 64);
        printf("trace: %s:\tdst=%s cpu=%d lwp=%p psref=%p target=%p\n", func, dst,
            cpu_index(curcpu()), curlwp, &ro->ro_psref, &rt->rt_psref);
}
#define RTCACHE_PSREF_TRACE(rt, ro)     rtcache_trace(__func__, (rt), (ro))
#else
#define RTCACHE_PSREF_TRACE(rt, ro)     do {} while (0)
#endif

static void
rtcache_ref(struct rtentry *rt, struct route *ro)
{

        KASSERT(rt != NULL);

#ifdef NET_MPSAFE
        RTCACHE_PSREF_TRACE(rt, ro);
        ro->ro_bound = curlwp_bind();
        /* XXX Use a real caller's address */
        PSREF_DEBUG_FILL_RETURN_ADDRESS(&ro->ro_psref);
        psref_acquire(&ro->ro_psref, &rt->rt_psref, rt_psref_class);
#endif
}

void
rtcache_unref(struct rtentry *rt, struct route *ro)
{

        if (rt == NULL)
                return;

#ifdef NET_MPSAFE
        psref_release(&ro->ro_psref, &rt->rt_psref, rt_psref_class);
        curlwp_bindx(ro->ro_bound);
        RTCACHE_PSREF_TRACE(rt, ro);
#endif
}

struct rtentry *
rtcache_validate(struct route *ro)
{
        struct rtentry *rt = NULL;

#ifdef NET_MPSAFE
retry:
#endif
        rtcache_invariants(ro);
        RT_RLOCK();
        if (ro->ro_rtcache_generation != rtcache_generation) {
                /* The cache is invalidated */
                rt = NULL;
                goto out;
        }

        rt = ro->_ro_rt;
        if (rt == NULL)
                goto out;

        if ((rt->rt_flags & RTF_UP) == 0) {
                rt = NULL;
                goto out;
        }
#ifdef NET_MPSAFE
        if (ISSET(rt->rt_flags, RTF_UPDATING)) {
                if (rt_wait_ok()) {
                        RT_UNLOCK();

                        /* We can wait until the update is complete */
                        rt_update_wait();
                        goto retry;
                } else {
                        rt = NULL;
                }
        } else
#endif
                rtcache_ref(rt, ro);
out:
        RT_UNLOCK();
        return rt;
}

struct rtentry *
rtcache_lookup2(struct route *ro, const struct sockaddr *dst,
    int clone, int *hitp)
{
        const struct sockaddr *odst;
        struct rtentry *rt = NULL;

        odst = rtcache_getdst(ro);
        if (odst == NULL)
                goto miss;

        if (sockaddr_cmp(odst, dst) != 0) {
                rtcache_free(ro);
                goto miss;
        }

        rt = rtcache_validate(ro);
        if (rt == NULL) {
                ro->_ro_rt = NULL;
                goto miss;
        }

        rtcache_invariants(ro);

        if (hitp != NULL)
                *hitp = 1;
        return rt;
miss:
        if (hitp != NULL)
                *hitp = 0;
        if (rtcache_setdst(ro, dst) == 0)
                rt = _rtcache_init(ro, clone);

        rtcache_invariants(ro);

        return rt;
}

void
rtcache_free(struct route *ro)
{

        ro->_ro_rt = NULL;
        if (ro->ro_sa != NULL) {
                sockaddr_free(ro->ro_sa);
                ro->ro_sa = NULL;
        }
        rtcache_invariants(ro);
}

int
rtcache_setdst(struct route *ro, const struct sockaddr *sa)
{
        KASSERT(sa != NULL);

        rtcache_invariants(ro);
        if (ro->ro_sa != NULL) {
                if (ro->ro_sa->sa_family == sa->sa_family) {
                        ro->_ro_rt = NULL;
                        sockaddr_copy(ro->ro_sa, ro->ro_sa->sa_len, sa);
                        rtcache_invariants(ro);
                        return 0;
                }
                /* free ro_sa, wrong family */
                rtcache_free(ro);
        }

        KASSERT(ro->_ro_rt == NULL);

        if ((ro->ro_sa = sockaddr_dup(sa, M_ZERO | M_NOWAIT)) == NULL) {
                rtcache_invariants(ro);
                return ENOMEM;
        }
        rtcache_invariants(ro);
        return 0;
}

static void
rtcache_percpu_init_cpu(void *p, void *arg __unused, struct cpu_info *ci __unused)
{
        struct route **rop = p;

        /*
         * We can't have struct route as percpu data because it can be destroyed
         * over a memory enlargement processing of percpu.
         */
        *rop = kmem_zalloc(sizeof(**rop), KM_SLEEP);
}

percpu_t *
rtcache_percpu_alloc(void)
{

        return percpu_create(sizeof(struct route *),
            rtcache_percpu_init_cpu, NULL, NULL);
}

const struct sockaddr *
rt_settag(struct rtentry *rt, const struct sockaddr *tag)
{
        if (rt->rt_tag != tag) {
                if (rt->rt_tag != NULL)
                        sockaddr_free(rt->rt_tag);
                rt->rt_tag = sockaddr_dup(tag, M_ZERO | M_NOWAIT);
        }
        return rt->rt_tag;
}

struct sockaddr *
rt_gettag(const struct rtentry *rt)
{
        return rt->rt_tag;
}

int
rt_check_reject_route(const struct rtentry *rt, const struct ifnet *ifp)
{

        if ((rt->rt_flags & RTF_REJECT) != 0) {
                /* Mimic looutput */
                if (ifp->if_flags & IFF_LOOPBACK)
                        return (rt->rt_flags & RTF_HOST) ?
                            EHOSTUNREACH : ENETUNREACH;
                else if (rt->rt_rmx.rmx_expire == 0 ||
                    time_uptime < rt->rt_rmx.rmx_expire)
                        return (rt->rt_flags & RTF_GATEWAY) ?
                            EHOSTUNREACH : EHOSTDOWN;
        }

        return 0;
}

void
rt_delete_matched_entries(sa_family_t family, int (*f)(struct rtentry *, void *),
    void *v, bool notify)
{

        for (;;) {
                int s;
                int error;
                struct rtentry *rt, *retrt = NULL;

                RT_RLOCK();
                s = splsoftnet();
                rt = rtbl_search_matched_entry(family, f, v);
                if (rt == NULL) {
                        splx(s);
                        RT_UNLOCK();
                        return;
                }
                rt_ref(rt);
                RT_REFCNT_TRACE(rt);
                splx(s);
                RT_UNLOCK();

                error = rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway,
                    rt_mask(rt), rt->rt_flags, &retrt);
                if (error == 0) {
                        KASSERT(retrt == rt);
                        KASSERT((retrt->rt_flags & RTF_UP) == 0);
                        if (notify)
                                rt_newmsg(RTM_DELETE, retrt);
                        retrt->rt_ifp = NULL;
                        rt_unref(rt);
                        RT_REFCNT_TRACE(rt);
                        rt_free(retrt);
                } else if (error == ESRCH) {
                        /* Someone deleted the entry already. */
                        rt_unref(rt);
                        RT_REFCNT_TRACE(rt);
                } else {
                        log(LOG_ERR, "%s: unable to delete rtentry @ %p, "
                            "error = %d\n", rt->rt_ifp->if_xname, rt, error);
                        /* XXX how to treat this case? */
                }
        }
}

static int
rt_walktree_locked(sa_family_t family, int (*f)(struct rtentry *, void *),
    void *v)
{

        return rtbl_walktree(family, f, v);
}

void
rt_replace_ifa_matched_entries(sa_family_t family,
    int (*f)(struct rtentry *, void *), void *v, struct ifaddr *ifa)
{

        for (;;) {
                int s;
#ifdef NET_MPSAFE
                int error;
#endif
                struct rtentry *rt;

                RT_RLOCK();
                s = splsoftnet();
                rt = rtbl_search_matched_entry(family, f, v);
                if (rt == NULL) {
                        splx(s);
                        RT_UNLOCK();
                        return;
                }
                rt_ref(rt);
                RT_REFCNT_TRACE(rt);
                splx(s);
                RT_UNLOCK();

#ifdef NET_MPSAFE
                error = rt_update_prepare(rt);
                if (error == 0) {
                        rt_replace_ifa(rt, ifa);
                        rt_update_finish(rt);
                        rt_newmsg(RTM_CHANGE, rt);
                } else {
                        /*
                         * If error != 0, the rtentry is being
                         * destroyed, so doing nothing doesn't
                         * matter.
                         */
                }
#else
                rt_replace_ifa(rt, ifa);
                rt_newmsg(RTM_CHANGE, rt);
#endif
                rt_unref(rt);
                RT_REFCNT_TRACE(rt);
        }
}

int
rt_walktree(sa_family_t family, int (*f)(struct rtentry *, void *), void *v)
{
        int error;

        RT_RLOCK();
        error = rt_walktree_locked(family, f, v);
        RT_UNLOCK();

        return error;
}

void
rt_unhandled(const char *func, const struct ifnet *ifp,
    const struct sockaddr *sa)
{
        char buf[256];

        sockaddr_format(sa, buf, sizeof(buf));
        printf("%s: %s: can't handle af%hhd (%s)\n", func, ifp->if_xname,
            sa->sa_family, buf);
}

#ifdef DDB

#include <machine/db_machdep.h>
#include <ddb/db_interface.h>
#include <ddb/db_output.h>

#define rt_expire rt_rmx.rmx_expire

static void
db_print_sa(const struct sockaddr *sa)
{
        int len;
        const u_char *p;

        if (sa == NULL) {
                db_printf("[NULL]");
                return;
        }

        p = (const u_char *)sa;
        len = sa->sa_len;
        db_printf("[");
        while (len > 0) {
                db_printf("%d", *p);
                p++; len--;
                if (len) db_printf(",");
        }
        db_printf("]\n");
}

static void
db_print_ifa(struct ifaddr *ifa)
{
        if (ifa == NULL)
                return;
        db_printf("  ifa_addr=");
        db_print_sa(ifa->ifa_addr);
        db_printf("  ifa_dsta=");
        db_print_sa(ifa->ifa_dstaddr);
        db_printf("  ifa_mask=");
        db_print_sa(ifa->ifa_netmask);
        db_printf("  flags=0x%x,refcnt=%d,metric=%d\n",
                          ifa->ifa_flags,
                          ifa->ifa_refcnt,
                          ifa->ifa_metric);
}

/*
 * Function to pass to rt_walktree().
 * Return non-zero error to abort walk.
 */
static int
db_show_rtentry(struct rtentry *rt, void *w)
{
        db_printf("rtentry=%p", rt);

        db_printf(" flags=0x%x refcnt=%d use=%"PRId64" expire=%"PRId64"\n",
                          rt->rt_flags, rt->rt_refcnt,
                          rt->rt_use, (uint64_t)rt->rt_expire);

        db_printf(" key="); db_print_sa(rt_getkey(rt));
        db_printf(" mask="); db_print_sa(rt_mask(rt));
        db_printf(" gw="); db_print_sa(rt->rt_gateway);

        db_printf(" ifp=%p ", rt->rt_ifp);
        if (rt->rt_ifp)
                db_printf("(%s)", rt->rt_ifp->if_xname);
        else
                db_printf("(NULL)");

        db_printf(" ifa=%p\n", rt->rt_ifa);
        db_print_ifa(rt->rt_ifa);

        db_printf(" gwroute=%p llinfo=%p\n",
                          rt->rt_gwroute, rt->rt_llinfo);

        return 0;
}

/*
 * Function to print all the route trees.
 * Use this from ddb:  "show routes"
 */
void
db_show_routes(db_expr_t addr, bool have_addr,
    db_expr_t count, const char *modif)
{

        /* Taking RT_LOCK will fail if LOCKDEBUG is enabled. */
        rt_walktree_locked(AF_INET, db_show_rtentry, NULL);
}
#endif