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      1 /*	$NetBSD: if_arp.c,v 1.234 2017/01/16 07:33:36 ryo Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Public Access Networks Corporation ("Panix").  It was developed under
      9  * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Copyright (c) 1982, 1986, 1988, 1993
     35  *	The Regents of the University of California.  All rights reserved.
     36  *
     37  * Redistribution and use in source and binary forms, with or without
     38  * modification, are permitted provided that the following conditions
     39  * are met:
     40  * 1. Redistributions of source code must retain the above copyright
     41  *    notice, this list of conditions and the following disclaimer.
     42  * 2. Redistributions in binary form must reproduce the above copyright
     43  *    notice, this list of conditions and the following disclaimer in the
     44  *    documentation and/or other materials provided with the distribution.
     45  * 3. Neither the name of the University nor the names of its contributors
     46  *    may be used to endorse or promote products derived from this software
     47  *    without specific prior written permission.
     48  *
     49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     59  * SUCH DAMAGE.
     60  *
     61  *	@(#)if_ether.c	8.2 (Berkeley) 9/26/94
     62  */
     63 
     64 /*
     65  * Ethernet address resolution protocol.
     66  * TODO:
     67  *	add "inuse/lock" bit (or ref. count) along with valid bit
     68  */
     69 
     70 #include <sys/cdefs.h>
     71 __KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.234 2017/01/16 07:33:36 ryo Exp $");
     72 
     73 #ifdef _KERNEL_OPT
     74 #include "opt_ddb.h"
     75 #include "opt_inet.h"
     76 #include "opt_net_mpsafe.h"
     77 #endif
     78 
     79 #ifdef INET
     80 
     81 #include "arp.h"
     82 #include "bridge.h"
     83 
     84 #include <sys/param.h>
     85 #include <sys/systm.h>
     86 #include <sys/callout.h>
     87 #include <sys/malloc.h>
     88 #include <sys/mbuf.h>
     89 #include <sys/socket.h>
     90 #include <sys/time.h>
     91 #include <sys/timetc.h>
     92 #include <sys/kernel.h>
     93 #include <sys/errno.h>
     94 #include <sys/ioctl.h>
     95 #include <sys/syslog.h>
     96 #include <sys/proc.h>
     97 #include <sys/protosw.h>
     98 #include <sys/domain.h>
     99 #include <sys/sysctl.h>
    100 #include <sys/socketvar.h>
    101 #include <sys/percpu.h>
    102 #include <sys/cprng.h>
    103 #include <sys/kmem.h>
    104 
    105 #include <net/ethertypes.h>
    106 #include <net/if.h>
    107 #include <net/if_dl.h>
    108 #include <net/if_token.h>
    109 #include <net/if_types.h>
    110 #include <net/if_ether.h>
    111 #include <net/if_llatbl.h>
    112 #include <net/net_osdep.h>
    113 #include <net/route.h>
    114 #include <net/net_stats.h>
    115 
    116 #include <netinet/in.h>
    117 #include <netinet/in_systm.h>
    118 #include <netinet/in_var.h>
    119 #include <netinet/ip.h>
    120 #include <netinet/if_inarp.h>
    121 
    122 #include "arcnet.h"
    123 #if NARCNET > 0
    124 #include <net/if_arc.h>
    125 #endif
    126 #include "fddi.h"
    127 #if NFDDI > 0
    128 #include <net/if_fddi.h>
    129 #endif
    130 #include "token.h"
    131 #include "carp.h"
    132 #if NCARP > 0
    133 #include <netinet/ip_carp.h>
    134 #endif
    135 
    136 #define SIN(s) ((struct sockaddr_in *)s)
    137 #define SRP(s) ((struct sockaddr_inarp *)s)
    138 
    139 /*
    140  * ARP trailer negotiation.  Trailer protocol is not IP specific,
    141  * but ARP request/response use IP addresses.
    142  */
    143 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
    144 
    145 /* timer values */
    146 static int	arpt_keep = (20*60);	/* once resolved, good for 20 more minutes */
    147 static int	arpt_down = 20;		/* once declared down, don't send for 20 secs */
    148 static int	arp_maxhold = 1;	/* number of packets to hold per ARP entry */
    149 #define	rt_expire rt_rmx.rmx_expire
    150 #define	rt_pksent rt_rmx.rmx_pksent
    151 
    152 int		ip_dad_count = PROBE_NUM;
    153 #ifdef ARP_DEBUG
    154 int		arp_debug = 1;
    155 #else
    156 int		arp_debug = 0;
    157 #endif
    158 
    159 static	void arp_init(void);
    160 
    161 static	void arprequest(struct ifnet *,
    162     const struct in_addr *, const struct in_addr *,
    163     const u_int8_t *);
    164 static	void arpannounce1(struct ifaddr *);
    165 static	struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *,
    166 	    const struct sockaddr *);
    167 static	void arptimer(void *);
    168 static	void arp_settimer(struct llentry *, int);
    169 static	struct llentry *arplookup(struct ifnet *, struct mbuf *,
    170 	    const struct in_addr *, const struct sockaddr *, int);
    171 static	struct llentry *arpcreate(struct ifnet *, struct mbuf *,
    172 	    const struct in_addr *, const struct sockaddr *, int);
    173 static	void in_arpinput(struct mbuf *);
    174 static	void in_revarpinput(struct mbuf *);
    175 static	void revarprequest(struct ifnet *);
    176 
    177 static	void arp_drainstub(void);
    178 
    179 static void arp_dad_timer(struct ifaddr *);
    180 static void arp_dad_start(struct ifaddr *);
    181 static void arp_dad_stop(struct ifaddr *);
    182 static void arp_dad_duplicated(struct ifaddr *, const char *);
    183 
    184 static void arp_init_llentry(struct ifnet *, struct llentry *);
    185 #if NTOKEN > 0
    186 static void arp_free_llentry_tokenring(struct llentry *);
    187 #endif
    188 
    189 struct	ifqueue arpintrq = {
    190 	.ifq_head = NULL,
    191 	.ifq_tail = NULL,
    192 	.ifq_len = 0,
    193 	.ifq_maxlen = 50,
    194 	.ifq_drops = 0,
    195 };
    196 static int	arp_maxtries = 5;
    197 static int	useloopback = 1;	/* use loopback interface for local traffic */
    198 
    199 static percpu_t *arpstat_percpu;
    200 
    201 #define	ARP_STAT_GETREF()	_NET_STAT_GETREF(arpstat_percpu)
    202 #define	ARP_STAT_PUTREF()	_NET_STAT_PUTREF(arpstat_percpu)
    203 
    204 #define	ARP_STATINC(x)		_NET_STATINC(arpstat_percpu, x)
    205 #define	ARP_STATADD(x, v)	_NET_STATADD(arpstat_percpu, x, v)
    206 
    207 /* revarp state */
    208 static struct	in_addr myip, srv_ip;
    209 static int	myip_initialized = 0;
    210 static int	revarp_in_progress = 0;
    211 static struct	ifnet *myip_ifp = NULL;
    212 
    213 static int arp_drainwanted;
    214 
    215 static int log_movements = 1;
    216 static int log_permanent_modify = 1;
    217 static int log_wrong_iface = 1;
    218 static int log_unknown_network = 1;
    219 
    220 /*
    221  * this should be elsewhere.
    222  */
    223 
    224 #define	LLA_ADDRSTRLEN	(16 * 3)
    225 
    226 static char *
    227 lla_snprintf(char *, u_int8_t *, int);
    228 
    229 static char *
    230 lla_snprintf(char *dst, u_int8_t *adrp, int len)
    231 {
    232 	int i;
    233 	char *p;
    234 
    235 	p = dst;
    236 
    237 	*p++ = hexdigits[(*adrp) >> 4];
    238 	*p++ = hexdigits[(*adrp++) & 0xf];
    239 
    240 	for (i = 1; i < len && i < 16; i++) {
    241 		*p++ = ':';
    242 		*p++ = hexdigits[(*adrp) >> 4];
    243 		*p++ = hexdigits[(*adrp++) & 0xf];
    244 	}
    245 
    246 	*p = 0;
    247 	return dst;
    248 }
    249 
    250 DOMAIN_DEFINE(arpdomain);	/* forward declare and add to link set */
    251 
    252 static void
    253 arp_fasttimo(void)
    254 {
    255 	if (arp_drainwanted) {
    256 		arp_drain();
    257 		arp_drainwanted = 0;
    258 	}
    259 }
    260 
    261 const struct protosw arpsw[] = {
    262 	{ .pr_type = 0,
    263 	  .pr_domain = &arpdomain,
    264 	  .pr_protocol = 0,
    265 	  .pr_flags = 0,
    266 	  .pr_input = 0,
    267 	  .pr_ctlinput = 0,
    268 	  .pr_ctloutput = 0,
    269 	  .pr_usrreqs = 0,
    270 	  .pr_init = arp_init,
    271 	  .pr_fasttimo = arp_fasttimo,
    272 	  .pr_slowtimo = 0,
    273 	  .pr_drain = arp_drainstub,
    274 	}
    275 };
    276 
    277 struct domain arpdomain = {
    278 	.dom_family = PF_ARP,
    279 	.dom_name = "arp",
    280 	.dom_protosw = arpsw,
    281 	.dom_protoswNPROTOSW = &arpsw[__arraycount(arpsw)],
    282 };
    283 
    284 static void sysctl_net_inet_arp_setup(struct sysctllog **);
    285 
    286 void
    287 arp_init(void)
    288 {
    289 
    290 	sysctl_net_inet_arp_setup(NULL);
    291 	arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS);
    292 	IFQ_LOCK_INIT(&arpintrq);
    293 }
    294 
    295 static void
    296 arp_drainstub(void)
    297 {
    298 	arp_drainwanted = 1;
    299 }
    300 
    301 /*
    302  * ARP protocol drain routine.  Called when memory is in short supply.
    303  * Called at splvm();  don't acquire softnet_lock as can be called from
    304  * hardware interrupt handlers.
    305  */
    306 void
    307 arp_drain(void)
    308 {
    309 
    310 	lltable_drain(AF_INET);
    311 }
    312 
    313 static void
    314 arptimer(void *arg)
    315 {
    316 	struct llentry *lle = arg;
    317 	struct ifnet *ifp;
    318 
    319 	if (lle == NULL)
    320 		return;
    321 
    322 	if (lle->la_flags & LLE_STATIC)
    323 		return;
    324 
    325 	LLE_WLOCK(lle);
    326 	if (callout_pending(&lle->la_timer)) {
    327 		/*
    328 		 * Here we are a bit odd here in the treatment of
    329 		 * active/pending. If the pending bit is set, it got
    330 		 * rescheduled before I ran. The active
    331 		 * bit we ignore, since if it was stopped
    332 		 * in ll_tablefree() and was currently running
    333 		 * it would have return 0 so the code would
    334 		 * not have deleted it since the callout could
    335 		 * not be stopped so we want to go through
    336 		 * with the delete here now. If the callout
    337 		 * was restarted, the pending bit will be back on and
    338 		 * we just want to bail since the callout_reset would
    339 		 * return 1 and our reference would have been removed
    340 		 * by arpresolve() below.
    341 		 */
    342 		LLE_WUNLOCK(lle);
    343 		return;
    344 	}
    345 	ifp = lle->lle_tbl->llt_ifp;
    346 
    347 	callout_stop(&lle->la_timer);
    348 
    349 	/* XXX: LOR avoidance. We still have ref on lle. */
    350 	LLE_WUNLOCK(lle);
    351 
    352 	IF_AFDATA_LOCK(ifp);
    353 	LLE_WLOCK(lle);
    354 
    355 	/* Guard against race with other llentry_free(). */
    356 	if (lle->la_flags & LLE_LINKED) {
    357 		size_t pkts_dropped;
    358 
    359 		LLE_REMREF(lle);
    360 		pkts_dropped = llentry_free(lle);
    361 		ARP_STATADD(ARP_STAT_DFRDROPPED, pkts_dropped);
    362 		ARP_STATADD(ARP_STAT_DFRTOTAL, pkts_dropped);
    363 	} else {
    364 		LLE_FREE_LOCKED(lle);
    365 	}
    366 
    367 	IF_AFDATA_UNLOCK(ifp);
    368 }
    369 
    370 static void
    371 arp_settimer(struct llentry *la, int sec)
    372 {
    373 
    374 	LLE_WLOCK_ASSERT(la);
    375 	LLE_ADDREF(la);
    376 	callout_reset(&la->la_timer, hz * sec, arptimer, la);
    377 }
    378 
    379 /*
    380  * We set the gateway for RTF_CLONING routes to a "prototype"
    381  * link-layer sockaddr whose interface type (if_type) and interface
    382  * index (if_index) fields are prepared.
    383  */
    384 static struct sockaddr *
    385 arp_setgate(struct rtentry *rt, struct sockaddr *gate,
    386     const struct sockaddr *netmask)
    387 {
    388 	const struct ifnet *ifp = rt->rt_ifp;
    389 	uint8_t namelen = strlen(ifp->if_xname);
    390 	uint8_t addrlen = ifp->if_addrlen;
    391 
    392 	/*
    393 	 * XXX: If this is a manually added route to interface
    394 	 * such as older version of routed or gated might provide,
    395 	 * restore cloning bit.
    396 	 */
    397 	if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL &&
    398 	    satocsin(netmask)->sin_addr.s_addr != 0xffffffff)
    399 		rt->rt_flags |= RTF_CONNECTED;
    400 
    401 	if ((rt->rt_flags & (RTF_CONNECTED | RTF_LOCAL))) {
    402 		union {
    403 			struct sockaddr sa;
    404 			struct sockaddr_storage ss;
    405 			struct sockaddr_dl sdl;
    406 		} u;
    407 		/*
    408 		 * Case 1: This route should come from a route to iface.
    409 		 */
    410 		sockaddr_dl_init(&u.sdl, sizeof(u.ss),
    411 		    ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen);
    412 		rt_setgate(rt, &u.sa);
    413 		gate = rt->rt_gateway;
    414 	}
    415 	return gate;
    416 }
    417 
    418 static void
    419 arp_init_llentry(struct ifnet *ifp, struct llentry *lle)
    420 {
    421 
    422 	switch (ifp->if_type) {
    423 #if NTOKEN > 0
    424 	case IFT_ISO88025:
    425 		lle->la_opaque = kmem_intr_alloc(sizeof(struct token_rif),
    426 		    KM_NOSLEEP);
    427 		lle->lle_ll_free = arp_free_llentry_tokenring;
    428 		break;
    429 #endif
    430 	}
    431 }
    432 
    433 #if NTOKEN > 0
    434 static void
    435 arp_free_llentry_tokenring(struct llentry *lle)
    436 {
    437 
    438 	kmem_intr_free(lle->la_opaque, sizeof(struct token_rif));
    439 }
    440 #endif
    441 
    442 /*
    443  * Parallel to llc_rtrequest.
    444  */
    445 void
    446 arp_rtrequest(int req, struct rtentry *rt, const struct rt_addrinfo *info)
    447 {
    448 	struct sockaddr *gate = rt->rt_gateway;
    449 	struct in_ifaddr *ia;
    450 	struct ifaddr *ifa;
    451 	struct ifnet *ifp = rt->rt_ifp;
    452 	int bound;
    453 	int s;
    454 
    455 	if (req == RTM_LLINFO_UPD) {
    456 		if ((ifa = info->rti_ifa) != NULL)
    457 			arpannounce1(ifa);
    458 		return;
    459 	}
    460 
    461 	if ((rt->rt_flags & RTF_GATEWAY) != 0) {
    462 		if (req != RTM_ADD)
    463 			return;
    464 
    465 		/*
    466 		 * linklayers with particular link MTU limitation.
    467 		 */
    468 		switch(ifp->if_type) {
    469 #if NFDDI > 0
    470 		case IFT_FDDI:
    471 			if (ifp->if_mtu > FDDIIPMTU)
    472 				rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    473 			break;
    474 #endif
    475 #if NARCNET > 0
    476 		case IFT_ARCNET:
    477 		    {
    478 			int arcipifmtu;
    479 
    480 			if (ifp->if_flags & IFF_LINK0)
    481 				arcipifmtu = arc_ipmtu;
    482 			else
    483 				arcipifmtu = ARCMTU;
    484 			if (ifp->if_mtu > arcipifmtu)
    485 				rt->rt_rmx.rmx_mtu = arcipifmtu;
    486 			break;
    487 		    }
    488 #endif
    489 		}
    490 		return;
    491 	}
    492 
    493 	switch (req) {
    494 	case RTM_SETGATE:
    495 		gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
    496 		break;
    497 	case RTM_ADD:
    498 		gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
    499 		if (gate == NULL) {
    500 			log(LOG_ERR, "%s: arp_setgate failed\n", __func__);
    501 			break;
    502 		}
    503 		if ((rt->rt_flags & RTF_CONNECTED) ||
    504 		    (rt->rt_flags & RTF_LOCAL)) {
    505 			/*
    506 			 * Give this route an expiration time, even though
    507 			 * it's a "permanent" route, so that routes cloned
    508 			 * from it do not need their expiration time set.
    509 			 */
    510 			KASSERT(time_uptime != 0);
    511 			rt->rt_expire = time_uptime;
    512 			/*
    513 			 * linklayers with particular link MTU limitation.
    514 			 */
    515 			switch (ifp->if_type) {
    516 #if NFDDI > 0
    517 			case IFT_FDDI:
    518 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    519 				    (rt->rt_rmx.rmx_mtu > FDDIIPMTU ||
    520 				     (rt->rt_rmx.rmx_mtu == 0 &&
    521 				      ifp->if_mtu > FDDIIPMTU)))
    522 					rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    523 				break;
    524 #endif
    525 #if NARCNET > 0
    526 			case IFT_ARCNET:
    527 			    {
    528 				int arcipifmtu;
    529 				if (ifp->if_flags & IFF_LINK0)
    530 					arcipifmtu = arc_ipmtu;
    531 				else
    532 					arcipifmtu = ARCMTU;
    533 
    534 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    535 				    (rt->rt_rmx.rmx_mtu > arcipifmtu ||
    536 				     (rt->rt_rmx.rmx_mtu == 0 &&
    537 				      ifp->if_mtu > arcipifmtu)))
    538 					rt->rt_rmx.rmx_mtu = arcipifmtu;
    539 				break;
    540 			    }
    541 #endif
    542 			}
    543 			if (rt->rt_flags & RTF_CONNECTED)
    544 				break;
    545 		}
    546 
    547 		bound = curlwp_bind();
    548 		/* Announce a new entry if requested. */
    549 		if (rt->rt_flags & RTF_ANNOUNCE) {
    550 			struct psref psref;
    551 			ia = in_get_ia_on_iface_psref(
    552 			    satocsin(rt_getkey(rt))->sin_addr, ifp, &psref);
    553 			if (ia != NULL) {
    554 				arpannounce(ifp, &ia->ia_ifa,
    555 				    CLLADDR(satocsdl(gate)));
    556 				ia4_release(ia, &psref);
    557 			}
    558 		}
    559 
    560 		if (gate->sa_family != AF_LINK ||
    561 		    gate->sa_len < sockaddr_dl_measure(0, ifp->if_addrlen)) {
    562 			log(LOG_DEBUG, "%s: bad gateway value\n", __func__);
    563 			goto out;
    564 		}
    565 
    566 		satosdl(gate)->sdl_type = ifp->if_type;
    567 		satosdl(gate)->sdl_index = ifp->if_index;
    568 
    569 		/* If the route is for a broadcast address mark it as such.
    570 		 * This way we can avoid an expensive call to in_broadcast()
    571 		 * in ip_output() most of the time (because the route passed
    572 		 * to ip_output() is almost always a host route). */
    573 		if (rt->rt_flags & RTF_HOST &&
    574 		    !(rt->rt_flags & RTF_BROADCAST) &&
    575 		    in_broadcast(satocsin(rt_getkey(rt))->sin_addr, rt->rt_ifp))
    576 			rt->rt_flags |= RTF_BROADCAST;
    577 		/* There is little point in resolving the broadcast address */
    578 		if (rt->rt_flags & RTF_BROADCAST)
    579 			goto out;
    580 
    581 		/*
    582 		 * When called from rt_ifa_addlocal, we cannot depend on that
    583 		 * the address (rt_getkey(rt)) exits in the address list of the
    584 		 * interface. So check RTF_LOCAL instead.
    585 		 */
    586 		if (rt->rt_flags & RTF_LOCAL) {
    587 			rt->rt_expire = 0;
    588 			if (useloopback) {
    589 				rt->rt_ifp = lo0ifp;
    590 				rt->rt_rmx.rmx_mtu = 0;
    591 			}
    592 			goto out;
    593 		}
    594 
    595 		s = pserialize_read_enter();
    596 		ia = in_get_ia_on_iface(satocsin(rt_getkey(rt))->sin_addr, ifp);
    597 		if (ia == NULL) {
    598 			pserialize_read_exit(s);
    599 			goto out;
    600 		}
    601 
    602 		rt->rt_expire = 0;
    603 		if (useloopback) {
    604 			rt->rt_ifp = lo0ifp;
    605 			rt->rt_rmx.rmx_mtu = 0;
    606 		}
    607 		rt->rt_flags |= RTF_LOCAL;
    608 		/*
    609 		 * make sure to set rt->rt_ifa to the interface
    610 		 * address we are using, otherwise we will have trouble
    611 		 * with source address selection.
    612 		 */
    613 		ifa = &ia->ia_ifa;
    614 		if (ifa != rt->rt_ifa)
    615 			/* Assume it doesn't sleep */
    616 			rt_replace_ifa(rt, ifa);
    617 		pserialize_read_exit(s);
    618 	out:
    619 		curlwp_bindx(bound);
    620 		break;
    621 	}
    622 }
    623 
    624 /*
    625  * Broadcast an ARP request. Caller specifies:
    626  *	- arp header source ip address
    627  *	- arp header target ip address
    628  *	- arp header source ethernet address
    629  */
    630 static void
    631 arprequest(struct ifnet *ifp,
    632     const struct in_addr *sip, const struct in_addr *tip,
    633     const u_int8_t *enaddr)
    634 {
    635 	struct mbuf *m;
    636 	struct arphdr *ah;
    637 	struct sockaddr sa;
    638 	uint64_t *arps;
    639 
    640 	KASSERT(sip != NULL);
    641 	KASSERT(tip != NULL);
    642 	KASSERT(enaddr != NULL);
    643 
    644 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    645 		return;
    646 	MCLAIM(m, &arpdomain.dom_mowner);
    647 	switch (ifp->if_type) {
    648 	case IFT_IEEE1394:
    649 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    650 		    ifp->if_addrlen;
    651 		break;
    652 	default:
    653 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    654 		    2 * ifp->if_addrlen;
    655 		break;
    656 	}
    657 	m->m_pkthdr.len = m->m_len;
    658 	MH_ALIGN(m, m->m_len);
    659 	ah = mtod(m, struct arphdr *);
    660 	memset(ah, 0, m->m_len);
    661 	switch (ifp->if_type) {
    662 	case IFT_IEEE1394:	/* RFC2734 */
    663 		/* fill it now for ar_tpa computation */
    664 		ah->ar_hrd = htons(ARPHRD_IEEE1394);
    665 		break;
    666 	default:
    667 		/* ifp->if_output will fill ar_hrd */
    668 		break;
    669 	}
    670 	ah->ar_pro = htons(ETHERTYPE_IP);
    671 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
    672 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
    673 	ah->ar_op = htons(ARPOP_REQUEST);
    674 	memcpy(ar_sha(ah), enaddr, ah->ar_hln);
    675 	memcpy(ar_spa(ah), sip, ah->ar_pln);
    676 	memcpy(ar_tpa(ah), tip, ah->ar_pln);
    677 	sa.sa_family = AF_ARP;
    678 	sa.sa_len = 2;
    679 	m->m_flags |= M_BCAST;
    680 	arps = ARP_STAT_GETREF();
    681 	arps[ARP_STAT_SNDTOTAL]++;
    682 	arps[ARP_STAT_SENDREQUEST]++;
    683 	ARP_STAT_PUTREF();
    684 	if_output_lock(ifp, ifp, m, &sa, NULL);
    685 }
    686 
    687 void
    688 arpannounce(struct ifnet *ifp, struct ifaddr *ifa, const uint8_t *enaddr)
    689 {
    690 	struct in_ifaddr *ia = ifatoia(ifa);
    691 	struct in_addr *ip = &IA_SIN(ifa)->sin_addr;
    692 
    693 	if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) {
    694 		ARPLOG(LOG_DEBUG, "%s not ready\n", ARPLOGADDR(*ip));
    695 		return;
    696 	}
    697 	arprequest(ifp, ip, ip, enaddr);
    698 }
    699 
    700 static void
    701 arpannounce1(struct ifaddr *ifa)
    702 {
    703 
    704 	arpannounce(ifa->ifa_ifp, ifa, CLLADDR(ifa->ifa_ifp->if_sadl));
    705 }
    706 
    707 /*
    708  * Resolve an IP address into an ethernet address.  If success,
    709  * desten is filled in.  If there is no entry in arptab,
    710  * set one up and broadcast a request for the IP address.
    711  * Hold onto this mbuf and resend it once the address
    712  * is finally resolved.  A return value of 0 indicates
    713  * that desten has been filled in and the packet should be sent
    714  * normally; a return value of EWOULDBLOCK indicates that the packet has been
    715  * held pending resolution.
    716  * Any other value indicates an error.
    717  */
    718 int
    719 arpresolve(struct ifnet *ifp, const struct rtentry *rt, struct mbuf *m,
    720     const struct sockaddr *dst, void *desten, size_t destlen)
    721 {
    722 	struct llentry *la;
    723 	const char *create_lookup;
    724 	bool renew;
    725 	int error;
    726 
    727 	KASSERT(m != NULL);
    728 
    729 	la = arplookup(ifp, m, NULL, dst, 0);
    730 	if (la == NULL)
    731 		goto notfound;
    732 
    733 	if ((la->la_flags & LLE_VALID) &&
    734 	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
    735 		KASSERT(destlen >= ifp->if_addrlen);
    736 		memcpy(desten, &la->ll_addr, ifp->if_addrlen);
    737 		LLE_RUNLOCK(la);
    738 		return 0;
    739 	}
    740 
    741 notfound:
    742 #ifdef IFF_STATICARP /* FreeBSD */
    743 #define _IFF_NOARP (IFF_NOARP | IFF_STATICARP)
    744 #else
    745 #define _IFF_NOARP IFF_NOARP
    746 #endif
    747 	if (ifp->if_flags & _IFF_NOARP) {
    748 		if (la != NULL)
    749 			LLE_RUNLOCK(la);
    750 		error = ENOTSUP;
    751 		goto bad;
    752 	}
    753 #undef _IFF_NOARP
    754 	if (la == NULL) {
    755 		create_lookup = "create";
    756 		IF_AFDATA_WLOCK(ifp);
    757 		la = lla_create(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
    758 		IF_AFDATA_WUNLOCK(ifp);
    759 		if (la == NULL)
    760 			ARP_STATINC(ARP_STAT_ALLOCFAIL);
    761 		else
    762 			arp_init_llentry(ifp, la);
    763 	} else if (LLE_TRY_UPGRADE(la) == 0) {
    764 		create_lookup = "lookup";
    765 		LLE_RUNLOCK(la);
    766 		IF_AFDATA_RLOCK(ifp);
    767 		la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
    768 		IF_AFDATA_RUNLOCK(ifp);
    769 	}
    770 
    771 	error = EINVAL;
    772 	if (la == NULL) {
    773 		log(LOG_DEBUG,
    774 		    "%s: failed to %s llentry for %s on %s\n",
    775 		    __func__, create_lookup, inet_ntoa(satocsin(dst)->sin_addr),
    776 		    ifp->if_xname);
    777 		goto bad;
    778 	}
    779 
    780 	if ((la->la_flags & LLE_VALID) &&
    781 	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime))
    782 	{
    783 		KASSERT(destlen >= ifp->if_addrlen);
    784 		memcpy(desten, &la->ll_addr, ifp->if_addrlen);
    785 		renew = false;
    786 		/*
    787 		 * If entry has an expiry time and it is approaching,
    788 		 * see if we need to send an ARP request within this
    789 		 * arpt_down interval.
    790 		 */
    791 		if (!(la->la_flags & LLE_STATIC) &&
    792 		    time_uptime + la->la_preempt > la->la_expire)
    793 		{
    794 			renew = true;
    795 			la->la_preempt--;
    796 		}
    797 
    798 		LLE_WUNLOCK(la);
    799 
    800 		if (renew) {
    801 			const u_int8_t *enaddr =
    802 #if NCARP > 0
    803 			    (ifp->if_type == IFT_CARP) ?
    804 			    CLLADDR(ifp->if_sadl):
    805 #endif
    806 			    CLLADDR(ifp->if_sadl);
    807 			arprequest(ifp,
    808 			    &satocsin(rt->rt_ifa->ifa_addr)->sin_addr,
    809 			    &satocsin(dst)->sin_addr, enaddr);
    810 		}
    811 
    812 		return 0;
    813 	}
    814 
    815 	if (la->la_flags & LLE_STATIC) {   /* should not happen! */
    816 		LLE_RUNLOCK(la);
    817 		log(LOG_DEBUG, "%s: ouch, empty static llinfo for %s\n",
    818 		    __func__, inet_ntoa(satocsin(dst)->sin_addr));
    819 		error = EINVAL;
    820 		goto bad;
    821 	}
    822 
    823 	renew = (la->la_asked == 0 || la->la_expire != time_uptime);
    824 
    825 	/*
    826 	 * There is an arptab entry, but no ethernet address
    827 	 * response yet.  Add the mbuf to the list, dropping
    828 	 * the oldest packet if we have exceeded the system
    829 	 * setting.
    830 	 */
    831 	LLE_WLOCK_ASSERT(la);
    832 	if (la->la_numheld >= arp_maxhold) {
    833 		if (la->la_hold != NULL) {
    834 			struct mbuf *next = la->la_hold->m_nextpkt;
    835 			m_freem(la->la_hold);
    836 			la->la_hold = next;
    837 			la->la_numheld--;
    838 			ARP_STATINC(ARP_STAT_DFRDROPPED);
    839 			ARP_STATINC(ARP_STAT_DFRTOTAL);
    840 		}
    841 	}
    842 	if (la->la_hold != NULL) {
    843 		struct mbuf *curr = la->la_hold;
    844 		while (curr->m_nextpkt != NULL)
    845 			curr = curr->m_nextpkt;
    846 		curr->m_nextpkt = m;
    847 	} else
    848 		la->la_hold = m;
    849 	la->la_numheld++;
    850 	if (!renew)
    851 		LLE_DOWNGRADE(la);
    852 
    853 	/*
    854 	 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
    855 	 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
    856 	 * if we have already sent arp_maxtries ARP requests. Retransmit the
    857 	 * ARP request, but not faster than one request per second.
    858 	 */
    859 	if (la->la_asked < arp_maxtries)
    860 		error = EWOULDBLOCK;	/* First request. */
    861 	else
    862 		error = (rt != NULL && rt->rt_flags & RTF_GATEWAY) ?
    863 		    EHOSTUNREACH : EHOSTDOWN;
    864 
    865 	if (renew) {
    866 		const u_int8_t *enaddr =
    867 #if NCARP > 0
    868 		    (rt != NULL && rt->rt_ifp->if_type == IFT_CARP) ?
    869 		    CLLADDR(rt->rt_ifp->if_sadl):
    870 #endif
    871 		    CLLADDR(ifp->if_sadl);
    872 		la->la_expire = time_uptime;
    873 		arp_settimer(la, arpt_down);
    874 		la->la_asked++;
    875 		LLE_WUNLOCK(la);
    876 
    877 		if (rt != NULL) {
    878 			arprequest(ifp, &satocsin(rt->rt_ifa->ifa_addr)->sin_addr,
    879 			    &satocsin(dst)->sin_addr, enaddr);
    880 		} else {
    881 			struct sockaddr_in sin;
    882 			struct rtentry *_rt;
    883 
    884 			sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
    885 
    886 			/* XXX */
    887 			_rt = rtalloc1((struct sockaddr *)&sin, 0);
    888 			if (_rt == NULL)
    889 				goto bad;
    890 			arprequest(ifp,
    891 			    &satocsin(_rt->rt_ifa->ifa_addr)->sin_addr,
    892 			    &satocsin(dst)->sin_addr, enaddr);
    893 			rt_unref(_rt);
    894 		}
    895 		return error;
    896 	}
    897 
    898 	LLE_RUNLOCK(la);
    899 	return error;
    900 
    901 bad:
    902 	m_freem(m);
    903 	return error;
    904 }
    905 
    906 /*
    907  * Common length and type checks are done here,
    908  * then the protocol-specific routine is called.
    909  */
    910 void
    911 arpintr(void)
    912 {
    913 	struct mbuf *m;
    914 	struct arphdr *ar;
    915 	int s;
    916 	int arplen;
    917 
    918 #ifndef NET_MPSAFE
    919 	mutex_enter(softnet_lock);
    920 	KERNEL_LOCK(1, NULL);
    921 #endif
    922 	for (;;) {
    923 		struct ifnet *rcvif;
    924 
    925 		IFQ_LOCK(&arpintrq);
    926 		IF_DEQUEUE(&arpintrq, m);
    927 		IFQ_UNLOCK(&arpintrq);
    928 		if (m == NULL)
    929 			goto out;
    930 		if ((m->m_flags & M_PKTHDR) == 0)
    931 			panic("arpintr");
    932 
    933 		MCLAIM(m, &arpdomain.dom_mowner);
    934 		ARP_STATINC(ARP_STAT_RCVTOTAL);
    935 
    936 		/*
    937 		 * First, make sure we have at least struct arphdr.
    938 		 */
    939 		if (m->m_len < sizeof(struct arphdr) ||
    940 		    (ar = mtod(m, struct arphdr *)) == NULL)
    941 			goto badlen;
    942 
    943 		rcvif = m_get_rcvif(m, &s);
    944 		switch (rcvif->if_type) {
    945 		case IFT_IEEE1394:
    946 			arplen = sizeof(struct arphdr) +
    947 			    ar->ar_hln + 2 * ar->ar_pln;
    948 			break;
    949 		default:
    950 			arplen = sizeof(struct arphdr) +
    951 			    2 * ar->ar_hln + 2 * ar->ar_pln;
    952 			break;
    953 		}
    954 		m_put_rcvif(rcvif, &s);
    955 
    956 		if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */
    957 		    m->m_len >= arplen)
    958 			switch (ntohs(ar->ar_pro)) {
    959 			case ETHERTYPE_IP:
    960 			case ETHERTYPE_IPTRAILERS:
    961 				in_arpinput(m);
    962 				continue;
    963 			default:
    964 				ARP_STATINC(ARP_STAT_RCVBADPROTO);
    965 			}
    966 		else {
    967 badlen:
    968 			ARP_STATINC(ARP_STAT_RCVBADLEN);
    969 		}
    970 		m_freem(m);
    971 	}
    972 out:
    973 #ifndef NET_MPSAFE
    974 	KERNEL_UNLOCK_ONE(NULL);
    975 	mutex_exit(softnet_lock);
    976 #else
    977 	return; /* XXX gcc */
    978 #endif
    979 }
    980 
    981 /*
    982  * ARP for Internet protocols on 10 Mb/s Ethernet.
    983  * Algorithm is that given in RFC 826.
    984  * In addition, a sanity check is performed on the sender
    985  * protocol address, to catch impersonators.
    986  * We no longer handle negotiations for use of trailer protocol:
    987  * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
    988  * along with IP replies if we wanted trailers sent to us,
    989  * and also sent them in response to IP replies.
    990  * This allowed either end to announce the desire to receive
    991  * trailer packets.
    992  * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
    993  * but formerly didn't normally send requests.
    994  */
    995 static void
    996 in_arpinput(struct mbuf *m)
    997 {
    998 	struct arphdr *ah;
    999 	struct ifnet *ifp, *rcvif = NULL;
   1000 	struct llentry *la = NULL;
   1001 	struct in_ifaddr *ia = NULL;
   1002 #if NBRIDGE > 0
   1003 	struct in_ifaddr *bridge_ia = NULL;
   1004 #endif
   1005 #if NCARP > 0
   1006 	u_int32_t count = 0, index = 0;
   1007 #endif
   1008 	struct sockaddr sa;
   1009 	struct in_addr isaddr, itaddr, myaddr;
   1010 	int op;
   1011 	void *tha;
   1012 	uint64_t *arps;
   1013 	struct psref psref, psref_ia;
   1014 	int s;
   1015 	char llabuf[LLA_ADDRSTRLEN];
   1016 	char ipbuf[INET_ADDRSTRLEN];
   1017 
   1018 	if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT)))
   1019 		goto out;
   1020 	ah = mtod(m, struct arphdr *);
   1021 	op = ntohs(ah->ar_op);
   1022 
   1023 	rcvif = ifp = m_get_rcvif_psref(m, &psref);
   1024 	if (__predict_false(rcvif == NULL))
   1025 		goto drop;
   1026 	/*
   1027 	 * Fix up ah->ar_hrd if necessary, before using ar_tha() or
   1028 	 * ar_tpa().
   1029 	 */
   1030 	switch (ifp->if_type) {
   1031 	case IFT_IEEE1394:
   1032 		if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394)
   1033 			;
   1034 		else {
   1035 			/* XXX this is to make sure we compute ar_tha right */
   1036 			/* XXX check ar_hrd more strictly? */
   1037 			ah->ar_hrd = htons(ARPHRD_IEEE1394);
   1038 		}
   1039 		break;
   1040 	default:
   1041 		/* XXX check ar_hrd? */
   1042 		break;
   1043 	}
   1044 
   1045 	memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
   1046 	memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
   1047 
   1048 	if (m->m_flags & (M_BCAST|M_MCAST))
   1049 		ARP_STATINC(ARP_STAT_RCVMCAST);
   1050 
   1051 
   1052 	/*
   1053 	 * Search for a matching interface address
   1054 	 * or any address on the interface to use
   1055 	 * as a dummy address in the rest of this function
   1056 	 */
   1057 	s = pserialize_read_enter();
   1058 	IN_ADDRHASH_READER_FOREACH(ia, itaddr.s_addr) {
   1059 		if (!in_hosteq(ia->ia_addr.sin_addr, itaddr))
   1060 			continue;
   1061 #if NCARP > 0
   1062 		if (ia->ia_ifp->if_type == IFT_CARP &&
   1063 		    ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) ==
   1064 		    (IFF_UP|IFF_RUNNING))) {
   1065 			index++;
   1066 			if (ia->ia_ifp == rcvif &&
   1067 			    carp_iamatch(ia, ar_sha(ah),
   1068 			    &count, index)) {
   1069 				break;
   1070 			}
   1071 		} else
   1072 #endif
   1073 		if (ia->ia_ifp == rcvif)
   1074 			break;
   1075 #if NBRIDGE > 0
   1076 		/*
   1077 		 * If the interface we received the packet on
   1078 		 * is part of a bridge, check to see if we need
   1079 		 * to "bridge" the packet to ourselves at this
   1080 		 * layer.  Note we still prefer a perfect match,
   1081 		 * but allow this weaker match if necessary.
   1082 		 */
   1083 		if (rcvif->if_bridge != NULL &&
   1084 		    rcvif->if_bridge == ia->ia_ifp->if_bridge)
   1085 			bridge_ia = ia;
   1086 #endif /* NBRIDGE > 0 */
   1087 	}
   1088 
   1089 #if NBRIDGE > 0
   1090 	if (ia == NULL && bridge_ia != NULL) {
   1091 		ia = bridge_ia;
   1092 		m_put_rcvif_psref(rcvif, &psref);
   1093 		rcvif = NULL;
   1094 		/* FIXME */
   1095 		ifp = bridge_ia->ia_ifp;
   1096 	}
   1097 #endif
   1098 	if (ia != NULL)
   1099 		ia4_acquire(ia, &psref_ia);
   1100 	pserialize_read_exit(s);
   1101 
   1102 	if (ia == NULL) {
   1103 		ia = in_get_ia_on_iface_psref(isaddr, rcvif, &psref_ia);
   1104 		if (ia == NULL) {
   1105 			ia = in_get_ia_from_ifp_psref(ifp, &psref_ia);
   1106 			if (ia == NULL) {
   1107 				ARP_STATINC(ARP_STAT_RCVNOINT);
   1108 				goto out;
   1109 			}
   1110 		}
   1111 	}
   1112 
   1113 	myaddr = ia->ia_addr.sin_addr;
   1114 
   1115 	/* XXX checks for bridge case? */
   1116 	if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) {
   1117 		ARP_STATINC(ARP_STAT_RCVLOCALSHA);
   1118 		goto out;	/* it's from me, ignore it. */
   1119 	}
   1120 
   1121 	/* XXX checks for bridge case? */
   1122 	if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
   1123 		ARP_STATINC(ARP_STAT_RCVBCASTSHA);
   1124 		log(LOG_ERR,
   1125 		    "%s: arp: link address is broadcast for IP address %s!\n",
   1126 		    ifp->if_xname, in_fmtaddr(ipbuf, isaddr));
   1127 		goto out;
   1128 	}
   1129 
   1130 	/*
   1131 	 * If the source IP address is zero, this is an RFC 5227 ARP probe
   1132 	 */
   1133 	if (in_nullhost(isaddr))
   1134 		ARP_STATINC(ARP_STAT_RCVZEROSPA);
   1135 	else if (in_hosteq(isaddr, myaddr))
   1136 		ARP_STATINC(ARP_STAT_RCVLOCALSPA);
   1137 
   1138 	/*
   1139 	 * If the target IP address is zero, ignore the packet.
   1140 	 * This prevents the code below from tring to answer
   1141 	 * when we are using IP address zero (booting).
   1142 	 */
   1143 	if (in_nullhost(itaddr)) {
   1144 		ARP_STATINC(ARP_STAT_RCVZEROTPA);
   1145 		goto out;
   1146 	}
   1147 
   1148 	/* DAD check, RFC 5227 */
   1149 	if (in_hosteq(isaddr, myaddr) ||
   1150 	    (in_nullhost(isaddr) && in_hosteq(itaddr, myaddr)))
   1151 	{
   1152 		arp_dad_duplicated((struct ifaddr *)ia,
   1153 		    lla_snprintf(llabuf, ar_sha(ah), ah->ar_hln));
   1154 		goto out;
   1155 	}
   1156 
   1157 	if (in_nullhost(isaddr))
   1158 		goto reply;
   1159 
   1160 	if (in_hosteq(itaddr, myaddr))
   1161 		la = arpcreate(ifp, m, &isaddr, NULL, 1);
   1162 	else
   1163 		la = arplookup(ifp, m, &isaddr, NULL, 1);
   1164 	if (la == NULL)
   1165 		goto reply;
   1166 
   1167 	if ((la->la_flags & LLE_VALID) &&
   1168 	    memcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
   1169 		if (la->la_flags & LLE_STATIC) {
   1170 			ARP_STATINC(ARP_STAT_RCVOVERPERM);
   1171 			if (!log_permanent_modify)
   1172 				goto out;
   1173 			log(LOG_INFO,
   1174 			    "%s tried to overwrite permanent arp info"
   1175 			    " for %s\n",
   1176 			    lla_snprintf(llabuf, ar_sha(ah), ah->ar_hln),
   1177 			    in_fmtaddr(ipbuf, isaddr));
   1178 			goto out;
   1179 		} else if (la->lle_tbl->llt_ifp != ifp) {
   1180 			/* XXX should not happen? */
   1181 			ARP_STATINC(ARP_STAT_RCVOVERINT);
   1182 			if (!log_wrong_iface)
   1183 				goto out;
   1184 			log(LOG_INFO,
   1185 			    "%s on %s tried to overwrite "
   1186 			    "arp info for %s on %s\n",
   1187 			    lla_snprintf(llabuf, ar_sha(ah), ah->ar_hln),
   1188 			    ifp->if_xname, in_fmtaddr(ipbuf, isaddr),
   1189 			    la->lle_tbl->llt_ifp->if_xname);
   1190 				goto out;
   1191 		} else {
   1192 			ARP_STATINC(ARP_STAT_RCVOVER);
   1193 			if (log_movements)
   1194 				log(LOG_INFO, "arp info overwritten "
   1195 				    "for %s by %s\n",
   1196 				    in_fmtaddr(ipbuf, isaddr),
   1197 				    lla_snprintf(llabuf, ar_sha(ah),
   1198 				    ah->ar_hln));
   1199 		}
   1200 	}
   1201 
   1202 	/* XXX llentry should have addrlen? */
   1203 #if 0
   1204 	/*
   1205 	 * sanity check for the address length.
   1206 	 * XXX this does not work for protocols with variable address
   1207 	 * length. -is
   1208 	 */
   1209 	if (sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
   1210 		ARP_STATINC(ARP_STAT_RCVLENCHG);
   1211 		log(LOG_WARNING,
   1212 		    "arp from %s: new addr len %d, was %d\n",
   1213 		    in_fmtaddr(ipbuf, isaddr), ah->ar_hln, sdl->sdl_alen);
   1214 	}
   1215 #endif
   1216 
   1217 	if (ifp->if_addrlen != ah->ar_hln) {
   1218 		ARP_STATINC(ARP_STAT_RCVBADLEN);
   1219 		log(LOG_WARNING,
   1220 		    "arp from %s: addr len: new %d, i/f %d (ignored)\n",
   1221 		    in_fmtaddr(ipbuf, isaddr), ah->ar_hln,
   1222 		    ifp->if_addrlen);
   1223 		goto reply;
   1224 	}
   1225 
   1226 #if NTOKEN > 0
   1227 	/*
   1228 	 * XXX uses m_data and assumes the complete answer including
   1229 	 * XXX token-ring headers is in the same buf
   1230 	 */
   1231 	if (ifp->if_type == IFT_ISO88025) {
   1232 		struct token_header *trh;
   1233 
   1234 		trh = (struct token_header *)M_TRHSTART(m);
   1235 		if (trh->token_shost[0] & TOKEN_RI_PRESENT) {
   1236 			struct token_rif *rif;
   1237 			size_t riflen;
   1238 
   1239 			rif = TOKEN_RIF(trh);
   1240 			riflen = (ntohs(rif->tr_rcf) &
   1241 			    TOKEN_RCF_LEN_MASK) >> 8;
   1242 
   1243 			if (riflen > 2 &&
   1244 			    riflen < sizeof(struct token_rif) &&
   1245 			    (riflen & 1) == 0) {
   1246 				rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION);
   1247 				rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK);
   1248 				memcpy(TOKEN_RIF_LLE(la), rif, riflen);
   1249 			}
   1250 		}
   1251 	}
   1252 #endif /* NTOKEN > 0 */
   1253 
   1254 	KASSERT(sizeof(la->ll_addr) >= ifp->if_addrlen);
   1255 	(void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
   1256 	la->la_flags |= LLE_VALID;
   1257 	if ((la->la_flags & LLE_STATIC) == 0) {
   1258 		la->la_expire = time_uptime + arpt_keep;
   1259 		arp_settimer(la, arpt_keep);
   1260 	}
   1261 	la->la_asked = 0;
   1262 	/* rt->rt_flags &= ~RTF_REJECT; */
   1263 
   1264 	if (la->la_hold != NULL) {
   1265 		int n = la->la_numheld;
   1266 		struct mbuf *m_hold, *m_hold_next;
   1267 		struct sockaddr_in sin;
   1268 
   1269 		sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
   1270 
   1271 		m_hold = la->la_hold;
   1272 		la->la_hold = NULL;
   1273 		la->la_numheld = 0;
   1274 		/*
   1275 		 * We have to unlock here because if_output would call
   1276 		 * arpresolve
   1277 		 */
   1278 		LLE_WUNLOCK(la);
   1279 		ARP_STATADD(ARP_STAT_DFRSENT, n);
   1280 		ARP_STATADD(ARP_STAT_DFRTOTAL, n);
   1281 		for (; m_hold != NULL; m_hold = m_hold_next) {
   1282 			m_hold_next = m_hold->m_nextpkt;
   1283 			m_hold->m_nextpkt = NULL;
   1284 			if_output_lock(ifp, ifp, m_hold, sintosa(&sin), NULL);
   1285 		}
   1286 	} else
   1287 		LLE_WUNLOCK(la);
   1288 	la = NULL;
   1289 
   1290 reply:
   1291 	if (la != NULL) {
   1292 		LLE_WUNLOCK(la);
   1293 		la = NULL;
   1294 	}
   1295 	if (op != ARPOP_REQUEST) {
   1296 		if (op == ARPOP_REPLY)
   1297 			ARP_STATINC(ARP_STAT_RCVREPLY);
   1298 		goto out;
   1299 	}
   1300 	ARP_STATINC(ARP_STAT_RCVREQUEST);
   1301 	if (in_hosteq(itaddr, myaddr)) {
   1302 		/* If our address is unuseable, don't reply */
   1303 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
   1304 			goto out;
   1305 		/* I am the target */
   1306 		tha = ar_tha(ah);
   1307 		if (tha)
   1308 			memcpy(tha, ar_sha(ah), ah->ar_hln);
   1309 		memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
   1310 	} else {
   1311 		/* Proxy ARP */
   1312 		struct llentry *lle = NULL;
   1313 		struct sockaddr_in sin;
   1314 #if NCARP > 0
   1315 		struct ifnet *_rcvif = m_get_rcvif(m, &s);
   1316 		if (ifp->if_type == IFT_CARP && _rcvif->if_type != IFT_CARP)
   1317 			goto out;
   1318 		m_put_rcvif(_rcvif, &s);
   1319 #endif
   1320 
   1321 		tha = ar_tha(ah);
   1322 
   1323 		sockaddr_in_init(&sin, &itaddr, 0);
   1324 
   1325 		IF_AFDATA_RLOCK(ifp);
   1326 		lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
   1327 		IF_AFDATA_RUNLOCK(ifp);
   1328 
   1329 		if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
   1330 			(void)memcpy(tha, ar_sha(ah), ah->ar_hln);
   1331 			(void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
   1332 			LLE_RUNLOCK(lle);
   1333 		} else {
   1334 			if (lle != NULL)
   1335 				LLE_RUNLOCK(lle);
   1336 			goto drop;
   1337 		}
   1338 	}
   1339 	ia4_release(ia, &psref_ia);
   1340 
   1341 	memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
   1342 	memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
   1343 	ah->ar_op = htons(ARPOP_REPLY);
   1344 	ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
   1345 	switch (ifp->if_type) {
   1346 	case IFT_IEEE1394:
   1347 		/*
   1348 		 * ieee1394 arp reply is broadcast
   1349 		 */
   1350 		m->m_flags &= ~M_MCAST;
   1351 		m->m_flags |= M_BCAST;
   1352 		m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln;
   1353 		break;
   1354 	default:
   1355 		m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */
   1356 		m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
   1357 		break;
   1358 	}
   1359 	m->m_pkthdr.len = m->m_len;
   1360 	sa.sa_family = AF_ARP;
   1361 	sa.sa_len = 2;
   1362 	arps = ARP_STAT_GETREF();
   1363 	arps[ARP_STAT_SNDTOTAL]++;
   1364 	arps[ARP_STAT_SNDREPLY]++;
   1365 	ARP_STAT_PUTREF();
   1366 	if_output_lock(ifp, ifp, m, &sa, NULL);
   1367 	if (rcvif != NULL)
   1368 		m_put_rcvif_psref(rcvif, &psref);
   1369 	return;
   1370 
   1371 out:
   1372 	if (la != NULL)
   1373 		LLE_WUNLOCK(la);
   1374 drop:
   1375 	if (ia != NULL)
   1376 		ia4_release(ia, &psref_ia);
   1377 	if (rcvif != NULL)
   1378 		m_put_rcvif_psref(rcvif, &psref);
   1379 	m_freem(m);
   1380 }
   1381 
   1382 /*
   1383  * Lookup or a new address in arptab.
   1384  */
   1385 static struct llentry *
   1386 arplookup(struct ifnet *ifp, struct mbuf *m, const struct in_addr *addr,
   1387     const struct sockaddr *sa, int wlock)
   1388 {
   1389 	struct sockaddr_in sin;
   1390 	struct llentry *la;
   1391 	int flags = wlock ? LLE_EXCLUSIVE : 0;
   1392 
   1393 
   1394 	if (sa == NULL) {
   1395 		KASSERT(addr != NULL);
   1396 		sockaddr_in_init(&sin, addr, 0);
   1397 		sa = sintocsa(&sin);
   1398 	}
   1399 
   1400 	IF_AFDATA_RLOCK(ifp);
   1401 	la = lla_lookup(LLTABLE(ifp), flags, sa);
   1402 	IF_AFDATA_RUNLOCK(ifp);
   1403 
   1404 	return la;
   1405 }
   1406 
   1407 static struct llentry *
   1408 arpcreate(struct ifnet *ifp, struct mbuf *m, const struct in_addr *addr,
   1409     const struct sockaddr *sa, int wlock)
   1410 {
   1411 	struct sockaddr_in sin;
   1412 	struct llentry *la;
   1413 	int flags = wlock ? LLE_EXCLUSIVE : 0;
   1414 
   1415 	if (sa == NULL) {
   1416 		KASSERT(addr != NULL);
   1417 		sockaddr_in_init(&sin, addr, 0);
   1418 		sa = sintocsa(&sin);
   1419 	}
   1420 
   1421 	la = arplookup(ifp, m, addr, sa, wlock);
   1422 
   1423 	if (la == NULL) {
   1424 		IF_AFDATA_WLOCK(ifp);
   1425 		la = lla_create(LLTABLE(ifp), flags, sa);
   1426 		IF_AFDATA_WUNLOCK(ifp);
   1427 
   1428 		if (la != NULL)
   1429 			arp_init_llentry(ifp, la);
   1430 	}
   1431 
   1432 	return la;
   1433 }
   1434 
   1435 int
   1436 arpioctl(u_long cmd, void *data)
   1437 {
   1438 
   1439 	return EOPNOTSUPP;
   1440 }
   1441 
   1442 void
   1443 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
   1444 {
   1445 	struct in_addr *ip;
   1446 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1447 
   1448 	/*
   1449 	 * Warn the user if another station has this IP address,
   1450 	 * but only if the interface IP address is not zero.
   1451 	 */
   1452 	ip = &IA_SIN(ifa)->sin_addr;
   1453 	if (!in_nullhost(*ip) &&
   1454 	    (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) == 0) {
   1455 		struct llentry *lle;
   1456 
   1457 		/*
   1458 		 * interface address is considered static entry
   1459 		 * because the output of the arp utility shows
   1460 		 * that L2 entry as permanent
   1461 		 */
   1462 		IF_AFDATA_WLOCK(ifp);
   1463 		lle = lla_create(LLTABLE(ifp), (LLE_IFADDR | LLE_STATIC),
   1464 				 (struct sockaddr *)IA_SIN(ifa));
   1465 		IF_AFDATA_WUNLOCK(ifp);
   1466 		if (lle == NULL)
   1467 			log(LOG_INFO, "%s: cannot create arp entry for"
   1468 			    " interface address\n", __func__);
   1469 		else {
   1470 			arp_init_llentry(ifp, lle);
   1471 			LLE_RUNLOCK(lle);
   1472 		}
   1473 	}
   1474 
   1475 	ifa->ifa_rtrequest = arp_rtrequest;
   1476 	ifa->ifa_flags |= RTF_CONNECTED;
   1477 
   1478 	/* ARP will handle DAD for this address. */
   1479 	if (in_nullhost(*ip)) {
   1480 		if (ia->ia_dad_stop != NULL)	/* safety */
   1481 			ia->ia_dad_stop(ifa);
   1482 		ia->ia_dad_start = NULL;
   1483 		ia->ia_dad_stop = NULL;
   1484 		ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1485 	} else {
   1486 		ia->ia_dad_start = arp_dad_start;
   1487 		ia->ia_dad_stop = arp_dad_stop;
   1488 		if (ia->ia4_flags & IN_IFF_TRYTENTATIVE)
   1489 			ia->ia4_flags |= IN_IFF_TENTATIVE;
   1490 		else
   1491 			arpannounce1(ifa);
   1492 	}
   1493 }
   1494 
   1495 TAILQ_HEAD(dadq_head, dadq);
   1496 struct dadq {
   1497 	TAILQ_ENTRY(dadq) dad_list;
   1498 	struct ifaddr *dad_ifa;
   1499 	int dad_count;		/* max ARP to send */
   1500 	int dad_arp_tcount;	/* # of trials to send ARP */
   1501 	int dad_arp_ocount;	/* ARP sent so far */
   1502 	int dad_arp_announce;	/* max ARP announcements */
   1503 	int dad_arp_acount;	/* # of announcements */
   1504 	struct callout dad_timer_ch;
   1505 };
   1506 MALLOC_JUSTDEFINE(M_IPARP, "ARP DAD", "ARP DAD Structure");
   1507 
   1508 static struct dadq_head dadq;
   1509 static int dad_init = 0;
   1510 static int dad_maxtry = 15;     /* max # of *tries* to transmit DAD packet */
   1511 static kmutex_t arp_dad_lock;
   1512 
   1513 static struct dadq *
   1514 arp_dad_find(struct ifaddr *ifa)
   1515 {
   1516 	struct dadq *dp;
   1517 
   1518 	KASSERT(mutex_owned(&arp_dad_lock));
   1519 
   1520 	TAILQ_FOREACH(dp, &dadq, dad_list) {
   1521 		if (dp->dad_ifa == ifa)
   1522 			return dp;
   1523 	}
   1524 	return NULL;
   1525 }
   1526 
   1527 static void
   1528 arp_dad_starttimer(struct dadq *dp, int ticks)
   1529 {
   1530 
   1531 	callout_reset(&dp->dad_timer_ch, ticks,
   1532 	    (void (*)(void *))arp_dad_timer, (void *)dp->dad_ifa);
   1533 }
   1534 
   1535 static void
   1536 arp_dad_stoptimer(struct dadq *dp)
   1537 {
   1538 
   1539 #ifdef NET_MPSAFE
   1540 	callout_halt(&dp->dad_timer_ch, NULL);
   1541 #else
   1542 	callout_halt(&dp->dad_timer_ch, softnet_lock);
   1543 #endif
   1544 }
   1545 
   1546 static void
   1547 arp_dad_output(struct dadq *dp, struct ifaddr *ifa)
   1548 {
   1549 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1550 	struct ifnet *ifp = ifa->ifa_ifp;
   1551 	struct in_addr sip;
   1552 
   1553 	dp->dad_arp_tcount++;
   1554 	if ((ifp->if_flags & IFF_UP) == 0)
   1555 		return;
   1556 	if ((ifp->if_flags & IFF_RUNNING) == 0)
   1557 		return;
   1558 
   1559 	dp->dad_arp_tcount = 0;
   1560 	dp->dad_arp_ocount++;
   1561 
   1562 	memset(&sip, 0, sizeof(sip));
   1563 	arprequest(ifa->ifa_ifp, &sip, &ia->ia_addr.sin_addr,
   1564 	    CLLADDR(ifa->ifa_ifp->if_sadl));
   1565 }
   1566 
   1567 /*
   1568  * Start Duplicate Address Detection (DAD) for specified interface address.
   1569  */
   1570 static void
   1571 arp_dad_start(struct ifaddr *ifa)
   1572 {
   1573 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1574 	struct dadq *dp;
   1575 	char ipbuf[INET_ADDRSTRLEN];
   1576 
   1577 	if (!dad_init) {
   1578 		TAILQ_INIT(&dadq);
   1579 		mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
   1580 		dad_init++;
   1581 	}
   1582 
   1583 	/*
   1584 	 * If we don't need DAD, don't do it.
   1585 	 * - DAD is disabled (ip_dad_count == 0)
   1586 	 */
   1587 	if (!(ia->ia4_flags & IN_IFF_TENTATIVE)) {
   1588 		log(LOG_DEBUG,
   1589 		    "%s: called with non-tentative address %s(%s)\n", __func__,
   1590 		    in_fmtaddr(ipbuf, ia->ia_addr.sin_addr),
   1591 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1592 		return;
   1593 	}
   1594 	if (!ip_dad_count) {
   1595 		ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1596 		rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1597 		arpannounce1(ifa);
   1598 		return;
   1599 	}
   1600 	KASSERT(ifa->ifa_ifp != NULL);
   1601 	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
   1602 		return;
   1603 
   1604 	mutex_enter(&arp_dad_lock);
   1605 	if (arp_dad_find(ifa) != NULL) {
   1606 		mutex_exit(&arp_dad_lock);
   1607 		/* DAD already in progress */
   1608 		return;
   1609 	}
   1610 
   1611 	dp = malloc(sizeof(*dp), M_IPARP, M_NOWAIT);
   1612 	if (dp == NULL) {
   1613 		mutex_exit(&arp_dad_lock);
   1614 		log(LOG_ERR, "%s: memory allocation failed for %s(%s)\n",
   1615 		    __func__, in_fmtaddr(ipbuf, ia->ia_addr.sin_addr),
   1616 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1617 		return;
   1618 	}
   1619 	memset(dp, 0, sizeof(*dp));
   1620 	callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
   1621 
   1622 	/*
   1623 	 * Send ARP packet for DAD, ip_dad_count times.
   1624 	 * Note that we must delay the first transmission.
   1625 	 */
   1626 	dp->dad_ifa = ifa;
   1627 	ifaref(ifa);	/* just for safety */
   1628 	dp->dad_count = ip_dad_count;
   1629 	dp->dad_arp_announce = 0; /* Will be set when starting to announce */
   1630 	dp->dad_arp_acount = dp->dad_arp_ocount = dp->dad_arp_tcount = 0;
   1631 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
   1632 
   1633 	ARPLOG(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
   1634 	    ARPLOGADDR(ia->ia_addr.sin_addr));
   1635 
   1636 	arp_dad_starttimer(dp, cprng_fast32() % (PROBE_WAIT * hz));
   1637 
   1638 	mutex_exit(&arp_dad_lock);
   1639 }
   1640 
   1641 /*
   1642  * terminate DAD unconditionally.  used for address removals.
   1643  */
   1644 static void
   1645 arp_dad_stop(struct ifaddr *ifa)
   1646 {
   1647 	struct dadq *dp;
   1648 
   1649 	if (!dad_init)
   1650 		return;
   1651 
   1652 	mutex_enter(&arp_dad_lock);
   1653 	dp = arp_dad_find(ifa);
   1654 	if (dp == NULL) {
   1655 		mutex_exit(&arp_dad_lock);
   1656 		/* DAD wasn't started yet */
   1657 		return;
   1658 	}
   1659 
   1660 	/* Prevent the timer from running anymore. */
   1661 	TAILQ_REMOVE(&dadq, dp, dad_list);
   1662 	mutex_exit(&arp_dad_lock);
   1663 
   1664 	arp_dad_stoptimer(dp);
   1665 
   1666 	free(dp, M_IPARP);
   1667 	dp = NULL;
   1668 	ifafree(ifa);
   1669 }
   1670 
   1671 static void
   1672 arp_dad_timer(struct ifaddr *ifa)
   1673 {
   1674 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1675 	struct dadq *dp;
   1676 	char ipbuf[INET_ADDRSTRLEN];
   1677 
   1678 	mutex_enter(softnet_lock);
   1679 	KERNEL_LOCK(1, NULL);
   1680 	mutex_enter(&arp_dad_lock);
   1681 
   1682 	/* Sanity check */
   1683 	if (ia == NULL) {
   1684 		log(LOG_ERR, "%s: called with null parameter\n", __func__);
   1685 		goto done;
   1686 	}
   1687 	dp = arp_dad_find(ifa);
   1688 	if (dp == NULL) {
   1689 		/* DAD seems to be stopping, so do nothing. */
   1690 		goto done;
   1691 	}
   1692 	if (ia->ia4_flags & IN_IFF_DUPLICATED) {
   1693 		log(LOG_ERR, "%s: called with duplicate address %s(%s)\n",
   1694 		    __func__, in_fmtaddr(ipbuf, ia->ia_addr.sin_addr),
   1695 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1696 		goto done;
   1697 	}
   1698 	if ((ia->ia4_flags & IN_IFF_TENTATIVE) == 0 && dp->dad_arp_acount == 0)
   1699 	{
   1700 		log(LOG_ERR, "%s: called with non-tentative address %s(%s)\n",
   1701 		    __func__, in_fmtaddr(ipbuf, ia->ia_addr.sin_addr),
   1702 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1703 		goto done;
   1704 	}
   1705 
   1706 	/* timeouted with IFF_{RUNNING,UP} check */
   1707 	if (dp->dad_arp_tcount > dad_maxtry) {
   1708 		ARPLOG(LOG_INFO, "%s: could not run DAD, driver problem?\n",
   1709 		    if_name(ifa->ifa_ifp));
   1710 
   1711 		TAILQ_REMOVE(&dadq, dp, dad_list);
   1712 		free(dp, M_IPARP);
   1713 		dp = NULL;
   1714 		ifafree(ifa);
   1715 		goto done;
   1716 	}
   1717 
   1718 	/* Need more checks? */
   1719 	if (dp->dad_arp_ocount < dp->dad_count) {
   1720 		int adelay;
   1721 
   1722 		/*
   1723 		 * We have more ARP to go.  Send ARP packet for DAD.
   1724 		 */
   1725 		arp_dad_output(dp, ifa);
   1726 		if (dp->dad_arp_ocount < dp->dad_count)
   1727 			adelay = (PROBE_MIN * hz) +
   1728 			    (cprng_fast32() %
   1729 			    ((PROBE_MAX * hz) - (PROBE_MIN * hz)));
   1730 		else
   1731 			adelay = ANNOUNCE_WAIT * hz;
   1732 		arp_dad_starttimer(dp, adelay);
   1733 		goto done;
   1734 	} else if (dp->dad_arp_acount == 0) {
   1735 		/*
   1736 		 * We are done with DAD.
   1737 		 * No duplicate address found.
   1738 		 */
   1739 		ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1740 		rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1741 		ARPLOG(LOG_DEBUG,
   1742 		    "%s: DAD complete for %s - no duplicates found\n",
   1743 		    if_name(ifa->ifa_ifp), ARPLOGADDR(ia->ia_addr.sin_addr));
   1744 		dp->dad_arp_announce = ANNOUNCE_NUM;
   1745 		goto announce;
   1746 	} else if (dp->dad_arp_acount < dp->dad_arp_announce) {
   1747 announce:
   1748 		/*
   1749 		 * Announce the address.
   1750 		 */
   1751 		arpannounce1(ifa);
   1752 		dp->dad_arp_acount++;
   1753 		if (dp->dad_arp_acount < dp->dad_arp_announce) {
   1754 			arp_dad_starttimer(dp, ANNOUNCE_INTERVAL * hz);
   1755 			goto done;
   1756 		}
   1757 		ARPLOG(LOG_DEBUG,
   1758 		    "%s: ARP announcement complete for %s\n",
   1759 		    if_name(ifa->ifa_ifp), ARPLOGADDR(ia->ia_addr.sin_addr));
   1760 	}
   1761 
   1762 	TAILQ_REMOVE(&dadq, dp, dad_list);
   1763 	free(dp, M_IPARP);
   1764 	dp = NULL;
   1765 	ifafree(ifa);
   1766 
   1767 done:
   1768 	mutex_exit(&arp_dad_lock);
   1769 	KERNEL_UNLOCK_ONE(NULL);
   1770 	mutex_exit(softnet_lock);
   1771 }
   1772 
   1773 static void
   1774 arp_dad_duplicated(struct ifaddr *ifa, const char *sha)
   1775 {
   1776 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1777 	struct ifnet *ifp = ifa->ifa_ifp;
   1778 	char ipbuf[INET_ADDRSTRLEN];
   1779 	const char *iastr;
   1780 
   1781 	iastr = in_fmtaddr(ipbuf, ia->ia_addr.sin_addr);
   1782 
   1783 	if (ia->ia4_flags & (IN_IFF_TENTATIVE|IN_IFF_DUPLICATED)) {
   1784 		log(LOG_ERR,
   1785 		    "%s: DAD duplicate address %s from %s\n",
   1786 		    if_name(ifp), iastr, sha);
   1787 	} else if (ia->ia_dad_defended == 0 ||
   1788 		   ia->ia_dad_defended < time_uptime - DEFEND_INTERVAL) {
   1789 		ia->ia_dad_defended = time_uptime;
   1790 		arpannounce1(ifa);
   1791 		log(LOG_ERR,
   1792 		    "%s: DAD defended address %s from %s\n",
   1793 		    if_name(ifp), iastr, sha);
   1794 		return;
   1795 	} else {
   1796 		/* If DAD is disabled, just report the duplicate. */
   1797 		if (ip_dad_count == 0) {
   1798 			log(LOG_ERR,
   1799 			    "%s: DAD ignoring duplicate address %s from %s\n",
   1800 			    if_name(ifp), iastr, sha);
   1801 			return;
   1802 		}
   1803 		log(LOG_ERR,
   1804 		    "%s: DAD defence failed for %s from %s\n",
   1805 		    if_name(ifp), iastr, sha);
   1806 	}
   1807 
   1808 	arp_dad_stop(ifa);
   1809 
   1810 	ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1811 	if ((ia->ia4_flags & IN_IFF_DUPLICATED) == 0) {
   1812 		ia->ia4_flags |= IN_IFF_DUPLICATED;
   1813 		/* Inform the routing socket of the duplicate address */
   1814 		rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1815 	}
   1816 }
   1817 
   1818 /*
   1819  * Called from 10 Mb/s Ethernet interrupt handlers
   1820  * when ether packet type ETHERTYPE_REVARP
   1821  * is received.  Common length and type checks are done here,
   1822  * then the protocol-specific routine is called.
   1823  */
   1824 void
   1825 revarpinput(struct mbuf *m)
   1826 {
   1827 	struct arphdr *ar;
   1828 
   1829 	if (m->m_len < sizeof(struct arphdr))
   1830 		goto out;
   1831 	ar = mtod(m, struct arphdr *);
   1832 #if 0 /* XXX I don't think we need this... and it will prevent other LL */
   1833 	if (ntohs(ar->ar_hrd) != ARPHRD_ETHER)
   1834 		goto out;
   1835 #endif
   1836 	if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
   1837 		goto out;
   1838 	switch (ntohs(ar->ar_pro)) {
   1839 	case ETHERTYPE_IP:
   1840 	case ETHERTYPE_IPTRAILERS:
   1841 		in_revarpinput(m);
   1842 		return;
   1843 
   1844 	default:
   1845 		break;
   1846 	}
   1847 out:
   1848 	m_freem(m);
   1849 }
   1850 
   1851 /*
   1852  * RARP for Internet protocols on 10 Mb/s Ethernet.
   1853  * Algorithm is that given in RFC 903.
   1854  * We are only using for bootstrap purposes to get an ip address for one of
   1855  * our interfaces.  Thus we support no user-interface.
   1856  *
   1857  * Since the contents of the RARP reply are specific to the interface that
   1858  * sent the request, this code must ensure that they are properly associated.
   1859  *
   1860  * Note: also supports ARP via RARP packets, per the RFC.
   1861  */
   1862 void
   1863 in_revarpinput(struct mbuf *m)
   1864 {
   1865 	struct arphdr *ah;
   1866 	void *tha;
   1867 	int op;
   1868 	struct ifnet *rcvif;
   1869 	int s;
   1870 
   1871 	ah = mtod(m, struct arphdr *);
   1872 	op = ntohs(ah->ar_op);
   1873 
   1874 	rcvif = m_get_rcvif(m, &s);
   1875 	switch (rcvif->if_type) {
   1876 	case IFT_IEEE1394:
   1877 		/* ARP without target hardware address is not supported */
   1878 		goto out;
   1879 	default:
   1880 		break;
   1881 	}
   1882 
   1883 	switch (op) {
   1884 	case ARPOP_REQUEST:
   1885 	case ARPOP_REPLY:	/* per RFC */
   1886 		m_put_rcvif(rcvif, &s);
   1887 		in_arpinput(m);
   1888 		return;
   1889 	case ARPOP_REVREPLY:
   1890 		break;
   1891 	case ARPOP_REVREQUEST:	/* handled by rarpd(8) */
   1892 	default:
   1893 		goto out;
   1894 	}
   1895 	if (!revarp_in_progress)
   1896 		goto out;
   1897 	if (rcvif != myip_ifp) /* !same interface */
   1898 		goto out;
   1899 	if (myip_initialized)
   1900 		goto wake;
   1901 	tha = ar_tha(ah);
   1902 	if (tha == NULL)
   1903 		goto out;
   1904 	if (memcmp(tha, CLLADDR(rcvif->if_sadl), rcvif->if_sadl->sdl_alen))
   1905 		goto out;
   1906 	memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip));
   1907 	memcpy(&myip, ar_tpa(ah), sizeof(myip));
   1908 	myip_initialized = 1;
   1909 wake:	/* Do wakeup every time in case it was missed. */
   1910 	wakeup((void *)&myip);
   1911 
   1912 out:
   1913 	m_put_rcvif(rcvif, &s);
   1914 	m_freem(m);
   1915 }
   1916 
   1917 /*
   1918  * Send a RARP request for the ip address of the specified interface.
   1919  * The request should be RFC 903-compliant.
   1920  */
   1921 static void
   1922 revarprequest(struct ifnet *ifp)
   1923 {
   1924 	struct sockaddr sa;
   1925 	struct mbuf *m;
   1926 	struct arphdr *ah;
   1927 	void *tha;
   1928 
   1929 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
   1930 		return;
   1931 	MCLAIM(m, &arpdomain.dom_mowner);
   1932 	m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
   1933 	    2*ifp->if_addrlen;
   1934 	m->m_pkthdr.len = m->m_len;
   1935 	MH_ALIGN(m, m->m_len);
   1936 	ah = mtod(m, struct arphdr *);
   1937 	memset(ah, 0, m->m_len);
   1938 	ah->ar_pro = htons(ETHERTYPE_IP);
   1939 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
   1940 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
   1941 	ah->ar_op = htons(ARPOP_REVREQUEST);
   1942 
   1943 	memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
   1944 	tha = ar_tha(ah);
   1945 	if (tha == NULL) {
   1946 		m_free(m);
   1947 		return;
   1948 	}
   1949 	memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln);
   1950 
   1951 	sa.sa_family = AF_ARP;
   1952 	sa.sa_len = 2;
   1953 	m->m_flags |= M_BCAST;
   1954 
   1955 	if_output_lock(ifp, ifp, m, &sa, NULL);
   1956 }
   1957 
   1958 /*
   1959  * RARP for the ip address of the specified interface, but also
   1960  * save the ip address of the server that sent the answer.
   1961  * Timeout if no response is received.
   1962  */
   1963 int
   1964 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in,
   1965     struct in_addr *clnt_in)
   1966 {
   1967 	int result, count = 20;
   1968 
   1969 	myip_initialized = 0;
   1970 	myip_ifp = ifp;
   1971 
   1972 	revarp_in_progress = 1;
   1973 	while (count--) {
   1974 		revarprequest(ifp);
   1975 		result = tsleep((void *)&myip, PSOCK, "revarp", hz/2);
   1976 		if (result != EWOULDBLOCK)
   1977 			break;
   1978 	}
   1979 	revarp_in_progress = 0;
   1980 
   1981 	if (!myip_initialized)
   1982 		return ENETUNREACH;
   1983 
   1984 	memcpy(serv_in, &srv_ip, sizeof(*serv_in));
   1985 	memcpy(clnt_in, &myip, sizeof(*clnt_in));
   1986 	return 0;
   1987 }
   1988 
   1989 void
   1990 arp_stat_add(int type, uint64_t count)
   1991 {
   1992 	ARP_STATADD(type, count);
   1993 }
   1994 
   1995 static int
   1996 sysctl_net_inet_arp_stats(SYSCTLFN_ARGS)
   1997 {
   1998 
   1999 	return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS);
   2000 }
   2001 
   2002 static void
   2003 sysctl_net_inet_arp_setup(struct sysctllog **clog)
   2004 {
   2005 	const struct sysctlnode *node;
   2006 
   2007 	sysctl_createv(clog, 0, NULL, NULL,
   2008 			CTLFLAG_PERMANENT,
   2009 			CTLTYPE_NODE, "inet", NULL,
   2010 			NULL, 0, NULL, 0,
   2011 			CTL_NET, PF_INET, CTL_EOL);
   2012 	sysctl_createv(clog, 0, NULL, &node,
   2013 			CTLFLAG_PERMANENT,
   2014 			CTLTYPE_NODE, "arp",
   2015 			SYSCTL_DESCR("Address Resolution Protocol"),
   2016 			NULL, 0, NULL, 0,
   2017 			CTL_NET, PF_INET, CTL_CREATE, CTL_EOL);
   2018 
   2019 	sysctl_createv(clog, 0, NULL, NULL,
   2020 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2021 			CTLTYPE_INT, "keep",
   2022 			SYSCTL_DESCR("Valid ARP entry lifetime in seconds"),
   2023 			NULL, 0, &arpt_keep, 0,
   2024 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2025 
   2026 	sysctl_createv(clog, 0, NULL, NULL,
   2027 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2028 			CTLTYPE_INT, "down",
   2029 			SYSCTL_DESCR("Failed ARP entry lifetime in seconds"),
   2030 			NULL, 0, &arpt_down, 0,
   2031 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2032 
   2033 	sysctl_createv(clog, 0, NULL, NULL,
   2034 			CTLFLAG_PERMANENT,
   2035 			CTLTYPE_STRUCT, "stats",
   2036 			SYSCTL_DESCR("ARP statistics"),
   2037 			sysctl_net_inet_arp_stats, 0, NULL, 0,
   2038 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2039 
   2040 	sysctl_createv(clog, 0, NULL, NULL,
   2041 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2042 			CTLTYPE_INT, "log_movements",
   2043 			SYSCTL_DESCR("log ARP replies from MACs different than"
   2044 			    " the one in the cache"),
   2045 			NULL, 0, &log_movements, 0,
   2046 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2047 
   2048 	sysctl_createv(clog, 0, NULL, NULL,
   2049 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2050 			CTLTYPE_INT, "log_permanent_modify",
   2051 			SYSCTL_DESCR("log ARP replies from MACs different than"
   2052 			    " the one in the permanent arp entry"),
   2053 			NULL, 0, &log_permanent_modify, 0,
   2054 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2055 
   2056 	sysctl_createv(clog, 0, NULL, NULL,
   2057 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2058 			CTLTYPE_INT, "log_wrong_iface",
   2059 			SYSCTL_DESCR("log ARP packets arriving on the wrong"
   2060 			    " interface"),
   2061 			NULL, 0, &log_wrong_iface, 0,
   2062 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2063 
   2064 	sysctl_createv(clog, 0, NULL, NULL,
   2065 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2066 			CTLTYPE_INT, "log_unknown_network",
   2067 			SYSCTL_DESCR("log ARP packets from non-local network"),
   2068 			NULL, 0, &log_unknown_network, 0,
   2069 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2070 
   2071 	sysctl_createv(clog, 0, NULL, NULL,
   2072 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2073 		       CTLTYPE_INT, "debug",
   2074 		       SYSCTL_DESCR("Enable ARP DAD debug output"),
   2075 		       NULL, 0, &arp_debug, 0,
   2076 		       CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2077 }
   2078 
   2079 #endif /* INET */
   2080