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      1 /*	$NetBSD: if_arp.c,v 1.221 2016/08/01 03:15:30 ozaki-r 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 1.221 2016/08/01 03:15:30 ozaki-r Exp $");
     72 
     73 #ifdef _KERNEL_OPT
     74 #include "opt_ddb.h"
     75 #include "opt_inet.h"
     76 #endif
     77 
     78 #ifdef INET
     79 
     80 #include "bridge.h"
     81 
     82 #include <sys/param.h>
     83 #include <sys/systm.h>
     84 #include <sys/callout.h>
     85 #include <sys/malloc.h>
     86 #include <sys/mbuf.h>
     87 #include <sys/socket.h>
     88 #include <sys/time.h>
     89 #include <sys/timetc.h>
     90 #include <sys/kernel.h>
     91 #include <sys/errno.h>
     92 #include <sys/ioctl.h>
     93 #include <sys/syslog.h>
     94 #include <sys/proc.h>
     95 #include <sys/protosw.h>
     96 #include <sys/domain.h>
     97 #include <sys/sysctl.h>
     98 #include <sys/socketvar.h>
     99 #include <sys/percpu.h>
    100 #include <sys/cprng.h>
    101 #include <sys/kmem.h>
    102 
    103 #include <net/ethertypes.h>
    104 #include <net/if.h>
    105 #include <net/if_dl.h>
    106 #include <net/if_token.h>
    107 #include <net/if_types.h>
    108 #include <net/if_ether.h>
    109 #include <net/if_llatbl.h>
    110 #include <net/net_osdep.h>
    111 #include <net/route.h>
    112 #include <net/net_stats.h>
    113 
    114 #include <netinet/in.h>
    115 #include <netinet/in_systm.h>
    116 #include <netinet/in_var.h>
    117 #include <netinet/ip.h>
    118 #include <netinet/if_inarp.h>
    119 
    120 #include "arcnet.h"
    121 #if NARCNET > 0
    122 #include <net/if_arc.h>
    123 #endif
    124 #include "fddi.h"
    125 #if NFDDI > 0
    126 #include <net/if_fddi.h>
    127 #endif
    128 #include "token.h"
    129 #include "carp.h"
    130 #if NCARP > 0
    131 #include <netinet/ip_carp.h>
    132 #endif
    133 
    134 #define SIN(s) ((struct sockaddr_in *)s)
    135 #define SRP(s) ((struct sockaddr_inarp *)s)
    136 
    137 /*
    138  * ARP trailer negotiation.  Trailer protocol is not IP specific,
    139  * but ARP request/response use IP addresses.
    140  */
    141 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
    142 
    143 /* timer values */
    144 static int	arpt_keep = (20*60);	/* once resolved, good for 20 more minutes */
    145 static int	arpt_down = 20;		/* once declared down, don't send for 20 secs */
    146 static int	arp_maxhold = 1;	/* number of packets to hold per ARP entry */
    147 #define	rt_expire rt_rmx.rmx_expire
    148 #define	rt_pksent rt_rmx.rmx_pksent
    149 
    150 int		ip_dad_count = PROBE_NUM;
    151 #ifdef ARP_DEBUG
    152 static int	arp_debug = 1;
    153 #else
    154 static int	arp_debug = 0;
    155 #endif
    156 #define arplog(x)	do { if (arp_debug) log x; } while (/*CONSTCOND*/ 0)
    157 
    158 static	void arp_init(void);
    159 
    160 static	struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *,
    161 	    const struct sockaddr *);
    162 static	void arptimer(void *);
    163 static	void arp_settimer(struct llentry *, int);
    164 static	struct llentry *arplookup(struct ifnet *, struct mbuf *,
    165 	    const struct in_addr *, const struct sockaddr *, int);
    166 static	struct llentry *arpcreate(struct ifnet *, struct mbuf *,
    167 	    const struct in_addr *, const struct sockaddr *, int);
    168 static	void in_arpinput(struct mbuf *);
    169 static	void in_revarpinput(struct mbuf *);
    170 static	void revarprequest(struct ifnet *);
    171 
    172 static	void arp_drainstub(void);
    173 
    174 static void arp_dad_timer(struct ifaddr *);
    175 static void arp_dad_start(struct ifaddr *);
    176 static void arp_dad_stop(struct ifaddr *);
    177 static void arp_dad_duplicated(struct ifaddr *);
    178 
    179 static void arp_init_llentry(struct ifnet *, struct llentry *);
    180 #if NTOKEN > 0
    181 static void arp_free_llentry_tokenring(struct llentry *);
    182 #endif
    183 
    184 struct	ifqueue arpintrq = {
    185 	.ifq_head = NULL,
    186 	.ifq_tail = NULL,
    187 	.ifq_len = 0,
    188 	.ifq_maxlen = 50,
    189 	.ifq_drops = 0,
    190 };
    191 static int	arp_maxtries = 5;
    192 static int	useloopback = 1;	/* use loopback interface for local traffic */
    193 
    194 static percpu_t *arpstat_percpu;
    195 
    196 #define	ARP_STAT_GETREF()	_NET_STAT_GETREF(arpstat_percpu)
    197 #define	ARP_STAT_PUTREF()	_NET_STAT_PUTREF(arpstat_percpu)
    198 
    199 #define	ARP_STATINC(x)		_NET_STATINC(arpstat_percpu, x)
    200 #define	ARP_STATADD(x, v)	_NET_STATADD(arpstat_percpu, x, v)
    201 
    202 /* revarp state */
    203 static struct	in_addr myip, srv_ip;
    204 static int	myip_initialized = 0;
    205 static int	revarp_in_progress = 0;
    206 static struct	ifnet *myip_ifp = NULL;
    207 
    208 static int arp_drainwanted;
    209 
    210 static int log_movements = 1;
    211 static int log_permanent_modify = 1;
    212 static int log_wrong_iface = 1;
    213 static int log_unknown_network = 1;
    214 
    215 /*
    216  * this should be elsewhere.
    217  */
    218 
    219 static char *
    220 lla_snprintf(u_int8_t *, int);
    221 
    222 static char *
    223 lla_snprintf(u_int8_t *adrp, int len)
    224 {
    225 #define NUMBUFS 3
    226 	static char buf[NUMBUFS][16*3];
    227 	static int bnum = 0;
    228 
    229 	int i;
    230 	char *p;
    231 
    232 	p = buf[bnum];
    233 
    234 	*p++ = hexdigits[(*adrp)>>4];
    235 	*p++ = hexdigits[(*adrp++)&0xf];
    236 
    237 	for (i=1; i<len && i<16; i++) {
    238 		*p++ = ':';
    239 		*p++ = hexdigits[(*adrp)>>4];
    240 		*p++ = hexdigits[(*adrp++)&0xf];
    241 	}
    242 
    243 	*p = 0;
    244 	p = buf[bnum];
    245 	bnum = (bnum + 1) % NUMBUFS;
    246 	return p;
    247 }
    248 
    249 DOMAIN_DEFINE(arpdomain);	/* forward declare and add to link set */
    250 
    251 static void
    252 arp_fasttimo(void)
    253 {
    254 	if (arp_drainwanted) {
    255 		arp_drain();
    256 		arp_drainwanted = 0;
    257 	}
    258 }
    259 
    260 const struct protosw arpsw[] = {
    261 	{ .pr_type = 0,
    262 	  .pr_domain = &arpdomain,
    263 	  .pr_protocol = 0,
    264 	  .pr_flags = 0,
    265 	  .pr_input = 0,
    266 	  .pr_ctlinput = 0,
    267 	  .pr_ctloutput = 0,
    268 	  .pr_usrreqs = 0,
    269 	  .pr_init = arp_init,
    270 	  .pr_fasttimo = arp_fasttimo,
    271 	  .pr_slowtimo = 0,
    272 	  .pr_drain = arp_drainstub,
    273 	}
    274 };
    275 
    276 struct domain arpdomain = {
    277 	.dom_family = PF_ARP,
    278 	.dom_name = "arp",
    279 	.dom_protosw = arpsw,
    280 	.dom_protoswNPROTOSW = &arpsw[__arraycount(arpsw)],
    281 };
    282 
    283 static void sysctl_net_inet_arp_setup(struct sysctllog **);
    284 
    285 void
    286 arp_init(void)
    287 {
    288 
    289 	sysctl_net_inet_arp_setup(NULL);
    290 	arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS);
    291 }
    292 
    293 static void
    294 arp_drainstub(void)
    295 {
    296 	arp_drainwanted = 1;
    297 }
    298 
    299 /*
    300  * ARP protocol drain routine.  Called when memory is in short supply.
    301  * Called at splvm();  don't acquire softnet_lock as can be called from
    302  * hardware interrupt handlers.
    303  */
    304 void
    305 arp_drain(void)
    306 {
    307 
    308 	lltable_drain(AF_INET);
    309 }
    310 
    311 static void
    312 arptimer(void *arg)
    313 {
    314 	struct llentry *lle = arg;
    315 	struct ifnet *ifp;
    316 
    317 	if (lle == NULL)
    318 		return;
    319 
    320 	if (lle->la_flags & LLE_STATIC)
    321 		return;
    322 
    323 	LLE_WLOCK(lle);
    324 	if (callout_pending(&lle->la_timer)) {
    325 		/*
    326 		 * Here we are a bit odd here in the treatment of
    327 		 * active/pending. If the pending bit is set, it got
    328 		 * rescheduled before I ran. The active
    329 		 * bit we ignore, since if it was stopped
    330 		 * in ll_tablefree() and was currently running
    331 		 * it would have return 0 so the code would
    332 		 * not have deleted it since the callout could
    333 		 * not be stopped so we want to go through
    334 		 * with the delete here now. If the callout
    335 		 * was restarted, the pending bit will be back on and
    336 		 * we just want to bail since the callout_reset would
    337 		 * return 1 and our reference would have been removed
    338 		 * by arpresolve() below.
    339 		 */
    340 		LLE_WUNLOCK(lle);
    341 		return;
    342 	}
    343 	ifp = lle->lle_tbl->llt_ifp;
    344 
    345 	callout_stop(&lle->la_timer);
    346 
    347 	/* XXX: LOR avoidance. We still have ref on lle. */
    348 	LLE_WUNLOCK(lle);
    349 
    350 	IF_AFDATA_LOCK(ifp);
    351 	LLE_WLOCK(lle);
    352 
    353 	/* Guard against race with other llentry_free(). */
    354 	if (lle->la_flags & LLE_LINKED) {
    355 		size_t pkts_dropped;
    356 
    357 		LLE_REMREF(lle);
    358 		pkts_dropped = llentry_free(lle);
    359 		ARP_STATADD(ARP_STAT_DFRDROPPED, pkts_dropped);
    360 		ARP_STATADD(ARP_STAT_DFRTOTAL, pkts_dropped);
    361 	} else {
    362 		LLE_FREE_LOCKED(lle);
    363 	}
    364 
    365 	IF_AFDATA_UNLOCK(ifp);
    366 }
    367 
    368 static void
    369 arp_settimer(struct llentry *la, int sec)
    370 {
    371 
    372 	LLE_WLOCK_ASSERT(la);
    373 	LLE_ADDREF(la);
    374 	callout_reset(&la->la_timer, hz * sec, arptimer, la);
    375 }
    376 
    377 /*
    378  * We set the gateway for RTF_CLONING routes to a "prototype"
    379  * link-layer sockaddr whose interface type (if_type) and interface
    380  * index (if_index) fields are prepared.
    381  */
    382 static struct sockaddr *
    383 arp_setgate(struct rtentry *rt, struct sockaddr *gate,
    384     const struct sockaddr *netmask)
    385 {
    386 	const struct ifnet *ifp = rt->rt_ifp;
    387 	uint8_t namelen = strlen(ifp->if_xname);
    388 	uint8_t addrlen = ifp->if_addrlen;
    389 
    390 	/*
    391 	 * XXX: If this is a manually added route to interface
    392 	 * such as older version of routed or gated might provide,
    393 	 * restore cloning bit.
    394 	 */
    395 	if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL &&
    396 	    satocsin(netmask)->sin_addr.s_addr != 0xffffffff)
    397 		rt->rt_flags |= RTF_CONNECTED;
    398 
    399 	if ((rt->rt_flags & (RTF_CONNECTED | RTF_LOCAL))) {
    400 		union {
    401 			struct sockaddr sa;
    402 			struct sockaddr_storage ss;
    403 			struct sockaddr_dl sdl;
    404 		} u;
    405 		/*
    406 		 * Case 1: This route should come from a route to iface.
    407 		 */
    408 		sockaddr_dl_init(&u.sdl, sizeof(u.ss),
    409 		    ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen);
    410 		rt_setgate(rt, &u.sa);
    411 		gate = rt->rt_gateway;
    412 	}
    413 	return gate;
    414 }
    415 
    416 static void
    417 arp_init_llentry(struct ifnet *ifp, struct llentry *lle)
    418 {
    419 
    420 	switch (ifp->if_type) {
    421 #if NTOKEN > 0
    422 	case IFT_ISO88025:
    423 		lle->la_opaque = kmem_intr_alloc(sizeof(struct token_rif),
    424 		    KM_NOSLEEP);
    425 		lle->lle_ll_free = arp_free_llentry_tokenring;
    426 		break;
    427 #endif
    428 	}
    429 }
    430 
    431 #if NTOKEN > 0
    432 static void
    433 arp_free_llentry_tokenring(struct llentry *lle)
    434 {
    435 
    436 	kmem_intr_free(lle->la_opaque, sizeof(struct token_rif));
    437 }
    438 #endif
    439 
    440 /*
    441  * Parallel to llc_rtrequest.
    442  */
    443 void
    444 arp_rtrequest(int req, struct rtentry *rt, const struct rt_addrinfo *info)
    445 {
    446 	struct sockaddr *gate = rt->rt_gateway;
    447 	struct in_ifaddr *ia;
    448 	struct ifaddr *ifa;
    449 	struct ifnet *ifp = rt->rt_ifp;
    450 	int bound;
    451 	int s;
    452 
    453 	if (req == RTM_LLINFO_UPD) {
    454 		struct in_addr *in;
    455 
    456 		if ((ifa = info->rti_ifa) == NULL)
    457 			return;
    458 
    459 		in = &ifatoia(ifa)->ia_addr.sin_addr;
    460 
    461 		if (ifatoia(ifa)->ia4_flags &
    462 		    (IN_IFF_NOTREADY | IN_IFF_DETACHED))
    463 		{
    464 			arplog((LOG_DEBUG, "arp_request: %s not ready\n",
    465 			   in_fmtaddr(*in)));
    466 			return;
    467 		}
    468 
    469 		arprequest(ifa->ifa_ifp, in, in,
    470 		    CLLADDR(ifa->ifa_ifp->if_sadl));
    471 		return;
    472 	}
    473 
    474 	if ((rt->rt_flags & RTF_GATEWAY) != 0) {
    475 		if (req != RTM_ADD)
    476 			return;
    477 
    478 		/*
    479 		 * linklayers with particular link MTU limitation.
    480 		 */
    481 		switch(ifp->if_type) {
    482 #if NFDDI > 0
    483 		case IFT_FDDI:
    484 			if (ifp->if_mtu > FDDIIPMTU)
    485 				rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    486 			break;
    487 #endif
    488 #if NARCNET > 0
    489 		case IFT_ARCNET:
    490 		    {
    491 			int arcipifmtu;
    492 
    493 			if (ifp->if_flags & IFF_LINK0)
    494 				arcipifmtu = arc_ipmtu;
    495 			else
    496 				arcipifmtu = ARCMTU;
    497 			if (ifp->if_mtu > arcipifmtu)
    498 				rt->rt_rmx.rmx_mtu = arcipifmtu;
    499 			break;
    500 		    }
    501 #endif
    502 		}
    503 		return;
    504 	}
    505 
    506 	switch (req) {
    507 	case RTM_SETGATE:
    508 		gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
    509 		break;
    510 	case RTM_ADD:
    511 		gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]);
    512 		if (gate == NULL) {
    513 			log(LOG_ERR, "%s: arp_setgate failed\n", __func__);
    514 			break;
    515 		}
    516 		if ((rt->rt_flags & RTF_CONNECTED) ||
    517 		    (rt->rt_flags & RTF_LOCAL)) {
    518 			/*
    519 			 * Give this route an expiration time, even though
    520 			 * it's a "permanent" route, so that routes cloned
    521 			 * from it do not need their expiration time set.
    522 			 */
    523 			KASSERT(time_uptime != 0);
    524 			rt->rt_expire = time_uptime;
    525 			/*
    526 			 * linklayers with particular link MTU limitation.
    527 			 */
    528 			switch (ifp->if_type) {
    529 #if NFDDI > 0
    530 			case IFT_FDDI:
    531 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    532 				    (rt->rt_rmx.rmx_mtu > FDDIIPMTU ||
    533 				     (rt->rt_rmx.rmx_mtu == 0 &&
    534 				      ifp->if_mtu > FDDIIPMTU)))
    535 					rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    536 				break;
    537 #endif
    538 #if NARCNET > 0
    539 			case IFT_ARCNET:
    540 			    {
    541 				int arcipifmtu;
    542 				if (ifp->if_flags & IFF_LINK0)
    543 					arcipifmtu = arc_ipmtu;
    544 				else
    545 					arcipifmtu = ARCMTU;
    546 
    547 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    548 				    (rt->rt_rmx.rmx_mtu > arcipifmtu ||
    549 				     (rt->rt_rmx.rmx_mtu == 0 &&
    550 				      ifp->if_mtu > arcipifmtu)))
    551 					rt->rt_rmx.rmx_mtu = arcipifmtu;
    552 				break;
    553 			    }
    554 #endif
    555 			}
    556 			if (rt->rt_flags & RTF_CONNECTED)
    557 				break;
    558 		}
    559 
    560 		bound = curlwp_bind();
    561 		/* Announce a new entry if requested. */
    562 		if (rt->rt_flags & RTF_ANNOUNCE) {
    563 			struct psref psref;
    564 			ia = in_get_ia_on_iface_psref(
    565 			    satocsin(rt_getkey(rt))->sin_addr, ifp, &psref);
    566 			if (ia == NULL ||
    567 			    ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
    568 				;
    569 			else
    570 				arprequest(ifp,
    571 				    &satocsin(rt_getkey(rt))->sin_addr,
    572 				    &satocsin(rt_getkey(rt))->sin_addr,
    573 				    CLLADDR(satocsdl(gate)));
    574 			if (ia != NULL)
    575 				ia4_release(ia, &psref);
    576 		}
    577 
    578 		if (gate->sa_family != AF_LINK ||
    579 		    gate->sa_len < sockaddr_dl_measure(0, ifp->if_addrlen)) {
    580 			log(LOG_DEBUG, "%s: bad gateway value\n", __func__);
    581 			goto out;
    582 		}
    583 
    584 		satosdl(gate)->sdl_type = ifp->if_type;
    585 		satosdl(gate)->sdl_index = ifp->if_index;
    586 
    587 		/* If the route is for a broadcast address mark it as such.
    588 		 * This way we can avoid an expensive call to in_broadcast()
    589 		 * in ip_output() most of the time (because the route passed
    590 		 * to ip_output() is almost always a host route). */
    591 		if (rt->rt_flags & RTF_HOST &&
    592 		    !(rt->rt_flags & RTF_BROADCAST) &&
    593 		    in_broadcast(satocsin(rt_getkey(rt))->sin_addr, rt->rt_ifp))
    594 			rt->rt_flags |= RTF_BROADCAST;
    595 		/* There is little point in resolving the broadcast address */
    596 		if (rt->rt_flags & RTF_BROADCAST)
    597 			goto out;
    598 
    599 		/*
    600 		 * When called from rt_ifa_addlocal, we cannot depend on that
    601 		 * the address (rt_getkey(rt)) exits in the address list of the
    602 		 * interface. So check RTF_LOCAL instead.
    603 		 */
    604 		if (rt->rt_flags & RTF_LOCAL) {
    605 			rt->rt_expire = 0;
    606 			if (useloopback) {
    607 				rt->rt_ifp = lo0ifp;
    608 				rt->rt_rmx.rmx_mtu = 0;
    609 			}
    610 			goto out;
    611 		}
    612 
    613 		s = pserialize_read_enter();
    614 		ia = in_get_ia_on_iface(satocsin(rt_getkey(rt))->sin_addr, ifp);
    615 		if (ia == NULL) {
    616 			pserialize_read_exit(s);
    617 			goto out;
    618 		}
    619 
    620 		rt->rt_expire = 0;
    621 		if (useloopback) {
    622 			rt->rt_ifp = lo0ifp;
    623 			rt->rt_rmx.rmx_mtu = 0;
    624 		}
    625 		rt->rt_flags |= RTF_LOCAL;
    626 		/*
    627 		 * make sure to set rt->rt_ifa to the interface
    628 		 * address we are using, otherwise we will have trouble
    629 		 * with source address selection.
    630 		 */
    631 		ifa = &ia->ia_ifa;
    632 		if (ifa != rt->rt_ifa)
    633 			/* Assume it doesn't sleep */
    634 			rt_replace_ifa(rt, ifa);
    635 		pserialize_read_exit(s);
    636 	out:
    637 		curlwp_bindx(bound);
    638 		break;
    639 	}
    640 }
    641 
    642 /*
    643  * Broadcast an ARP request. Caller specifies:
    644  *	- arp header source ip address
    645  *	- arp header target ip address
    646  *	- arp header source ethernet address
    647  */
    648 void
    649 arprequest(struct ifnet *ifp,
    650     const struct in_addr *sip, const struct in_addr *tip,
    651     const u_int8_t *enaddr)
    652 {
    653 	struct mbuf *m;
    654 	struct arphdr *ah;
    655 	struct sockaddr sa;
    656 	uint64_t *arps;
    657 
    658 	KASSERT(sip != NULL);
    659 	KASSERT(tip != NULL);
    660 	KASSERT(enaddr != NULL);
    661 
    662 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    663 		return;
    664 	MCLAIM(m, &arpdomain.dom_mowner);
    665 	switch (ifp->if_type) {
    666 	case IFT_IEEE1394:
    667 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    668 		    ifp->if_addrlen;
    669 		break;
    670 	default:
    671 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    672 		    2 * ifp->if_addrlen;
    673 		break;
    674 	}
    675 	m->m_pkthdr.len = m->m_len;
    676 	MH_ALIGN(m, m->m_len);
    677 	ah = mtod(m, struct arphdr *);
    678 	memset(ah, 0, m->m_len);
    679 	switch (ifp->if_type) {
    680 	case IFT_IEEE1394:	/* RFC2734 */
    681 		/* fill it now for ar_tpa computation */
    682 		ah->ar_hrd = htons(ARPHRD_IEEE1394);
    683 		break;
    684 	default:
    685 		/* ifp->if_output will fill ar_hrd */
    686 		break;
    687 	}
    688 	ah->ar_pro = htons(ETHERTYPE_IP);
    689 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
    690 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
    691 	ah->ar_op = htons(ARPOP_REQUEST);
    692 	memcpy(ar_sha(ah), enaddr, ah->ar_hln);
    693 	memcpy(ar_spa(ah), sip, ah->ar_pln);
    694 	memcpy(ar_tpa(ah), tip, ah->ar_pln);
    695 	sa.sa_family = AF_ARP;
    696 	sa.sa_len = 2;
    697 	m->m_flags |= M_BCAST;
    698 	arps = ARP_STAT_GETREF();
    699 	arps[ARP_STAT_SNDTOTAL]++;
    700 	arps[ARP_STAT_SENDREQUEST]++;
    701 	ARP_STAT_PUTREF();
    702 	if_output_lock(ifp, ifp, m, &sa, NULL);
    703 }
    704 
    705 /*
    706  * Resolve an IP address into an ethernet address.  If success,
    707  * desten is filled in.  If there is no entry in arptab,
    708  * set one up and broadcast a request for the IP address.
    709  * Hold onto this mbuf and resend it once the address
    710  * is finally resolved.  A return value of 0 indicates
    711  * that desten has been filled in and the packet should be sent
    712  * normally; a return value of EWOULDBLOCK indicates that the packet has been
    713  * held pending resolution.
    714  * Any other value indicates an error.
    715  */
    716 int
    717 arpresolve(struct ifnet *ifp, const struct rtentry *rt, struct mbuf *m,
    718     const struct sockaddr *dst, void *desten, size_t destlen)
    719 {
    720 	struct llentry *la;
    721 	const char *create_lookup;
    722 	bool renew;
    723 	int error;
    724 
    725 	KASSERT(m != NULL);
    726 
    727 	la = arplookup(ifp, m, NULL, dst, 0);
    728 	if (la == NULL)
    729 		goto notfound;
    730 
    731 	if ((la->la_flags & LLE_VALID) &&
    732 	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
    733 		KASSERT(destlen >= ifp->if_addrlen);
    734 		memcpy(desten, &la->ll_addr, ifp->if_addrlen);
    735 		LLE_RUNLOCK(la);
    736 		return 0;
    737 	}
    738 
    739 notfound:
    740 #ifdef IFF_STATICARP /* FreeBSD */
    741 #define _IFF_NOARP (IFF_NOARP | IFF_STATICARP)
    742 #else
    743 #define _IFF_NOARP IFF_NOARP
    744 #endif
    745 	if (ifp->if_flags & _IFF_NOARP) {
    746 		if (la != NULL)
    747 			LLE_RUNLOCK(la);
    748 		error = ENOTSUP;
    749 		goto bad;
    750 	}
    751 #undef _IFF_NOARP
    752 	if (la == NULL) {
    753 		create_lookup = "create";
    754 		IF_AFDATA_WLOCK(ifp);
    755 		la = lla_create(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
    756 		IF_AFDATA_WUNLOCK(ifp);
    757 		if (la == NULL)
    758 			ARP_STATINC(ARP_STAT_ALLOCFAIL);
    759 		else
    760 			arp_init_llentry(ifp, la);
    761 	} else if (LLE_TRY_UPGRADE(la) == 0) {
    762 		create_lookup = "lookup";
    763 		LLE_RUNLOCK(la);
    764 		IF_AFDATA_RLOCK(ifp);
    765 		la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
    766 		IF_AFDATA_RUNLOCK(ifp);
    767 	}
    768 
    769 	error = EINVAL;
    770 	if (la == NULL) {
    771 		log(LOG_DEBUG,
    772 		    "%s: failed to %s llentry for %s on %s\n",
    773 		    __func__, create_lookup, inet_ntoa(satocsin(dst)->sin_addr),
    774 		    ifp->if_xname);
    775 		goto bad;
    776 	}
    777 
    778 	if ((la->la_flags & LLE_VALID) &&
    779 	    ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime))
    780 	{
    781 		KASSERT(destlen >= ifp->if_addrlen);
    782 		memcpy(desten, &la->ll_addr, ifp->if_addrlen);
    783 		renew = false;
    784 		/*
    785 		 * If entry has an expiry time and it is approaching,
    786 		 * see if we need to send an ARP request within this
    787 		 * arpt_down interval.
    788 		 */
    789 		if (!(la->la_flags & LLE_STATIC) &&
    790 		    time_uptime + la->la_preempt > la->la_expire)
    791 		{
    792 			renew = true;
    793 			la->la_preempt--;
    794 		}
    795 
    796 		LLE_WUNLOCK(la);
    797 
    798 		if (renew) {
    799 			const u_int8_t *enaddr =
    800 #if NCARP > 0
    801 			    (ifp->if_type == IFT_CARP) ?
    802 			    CLLADDR(ifp->if_sadl):
    803 #endif
    804 			    CLLADDR(ifp->if_sadl);
    805 			arprequest(ifp,
    806 			    &satocsin(rt->rt_ifa->ifa_addr)->sin_addr,
    807 			    &satocsin(dst)->sin_addr, enaddr);
    808 		}
    809 
    810 		return 0;
    811 	}
    812 
    813 	if (la->la_flags & LLE_STATIC) {   /* should not happen! */
    814 		LLE_RUNLOCK(la);
    815 		log(LOG_DEBUG, "%s: ouch, empty static llinfo for %s\n",
    816 		    __func__, inet_ntoa(satocsin(dst)->sin_addr));
    817 		error = EINVAL;
    818 		goto bad;
    819 	}
    820 
    821 	renew = (la->la_asked == 0 || la->la_expire != time_uptime);
    822 
    823 	/*
    824 	 * There is an arptab entry, but no ethernet address
    825 	 * response yet.  Add the mbuf to the list, dropping
    826 	 * the oldest packet if we have exceeded the system
    827 	 * setting.
    828 	 */
    829 	LLE_WLOCK_ASSERT(la);
    830 	if (la->la_numheld >= arp_maxhold) {
    831 		if (la->la_hold != NULL) {
    832 			struct mbuf *next = la->la_hold->m_nextpkt;
    833 			m_freem(la->la_hold);
    834 			la->la_hold = next;
    835 			la->la_numheld--;
    836 			ARP_STATINC(ARP_STAT_DFRDROPPED);
    837 			ARP_STATINC(ARP_STAT_DFRTOTAL);
    838 		}
    839 	}
    840 	if (la->la_hold != NULL) {
    841 		struct mbuf *curr = la->la_hold;
    842 		while (curr->m_nextpkt != NULL)
    843 			curr = curr->m_nextpkt;
    844 		curr->m_nextpkt = m;
    845 	} else
    846 		la->la_hold = m;
    847 	la->la_numheld++;
    848 	if (!renew)
    849 		LLE_DOWNGRADE(la);
    850 
    851 	/*
    852 	 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
    853 	 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
    854 	 * if we have already sent arp_maxtries ARP requests. Retransmit the
    855 	 * ARP request, but not faster than one request per second.
    856 	 */
    857 	if (la->la_asked < arp_maxtries)
    858 		error = EWOULDBLOCK;	/* First request. */
    859 	else
    860 		error = (rt != NULL && rt->rt_flags & RTF_GATEWAY) ?
    861 		    EHOSTUNREACH : EHOSTDOWN;
    862 
    863 	if (renew) {
    864 		const u_int8_t *enaddr =
    865 #if NCARP > 0
    866 		    (rt != NULL && rt->rt_ifp->if_type == IFT_CARP) ?
    867 		    CLLADDR(rt->rt_ifp->if_sadl):
    868 #endif
    869 		    CLLADDR(ifp->if_sadl);
    870 		la->la_expire = time_uptime;
    871 		arp_settimer(la, arpt_down);
    872 		la->la_asked++;
    873 		LLE_WUNLOCK(la);
    874 
    875 		if (rt != NULL) {
    876 			arprequest(ifp, &satocsin(rt->rt_ifa->ifa_addr)->sin_addr,
    877 			    &satocsin(dst)->sin_addr, enaddr);
    878 		} else {
    879 			struct sockaddr_in sin;
    880 			struct rtentry *_rt;
    881 
    882 			sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
    883 
    884 			/* XXX */
    885 			_rt = rtalloc1((struct sockaddr *)&sin, 0);
    886 			if (_rt == NULL)
    887 				goto bad;
    888 			arprequest(ifp,
    889 			    &satocsin(_rt->rt_ifa->ifa_addr)->sin_addr,
    890 			    &satocsin(dst)->sin_addr, enaddr);
    891 			rtfree(_rt);
    892 		}
    893 		return error;
    894 	}
    895 
    896 	LLE_RUNLOCK(la);
    897 	return error;
    898 
    899 bad:
    900 	m_freem(m);
    901 	return error;
    902 }
    903 
    904 /*
    905  * Common length and type checks are done here,
    906  * then the protocol-specific routine is called.
    907  */
    908 void
    909 arpintr(void)
    910 {
    911 	struct mbuf *m;
    912 	struct arphdr *ar;
    913 	int s;
    914 	int arplen;
    915 
    916 	mutex_enter(softnet_lock);
    917 	KERNEL_LOCK(1, NULL);
    918 	while (arpintrq.ifq_head) {
    919 		struct ifnet *rcvif;
    920 
    921 		s = splnet();
    922 		IF_DEQUEUE(&arpintrq, m);
    923 		splx(s);
    924 		if (m == NULL || (m->m_flags & M_PKTHDR) == 0)
    925 			panic("arpintr");
    926 
    927 		MCLAIM(m, &arpdomain.dom_mowner);
    928 		ARP_STATINC(ARP_STAT_RCVTOTAL);
    929 
    930 		/*
    931 		 * First, make sure we have at least struct arphdr.
    932 		 */
    933 		if (m->m_len < sizeof(struct arphdr) ||
    934 		    (ar = mtod(m, struct arphdr *)) == NULL)
    935 			goto badlen;
    936 
    937 		rcvif = m_get_rcvif(m, &s);
    938 		switch (rcvif->if_type) {
    939 		case IFT_IEEE1394:
    940 			arplen = sizeof(struct arphdr) +
    941 			    ar->ar_hln + 2 * ar->ar_pln;
    942 			break;
    943 		default:
    944 			arplen = sizeof(struct arphdr) +
    945 			    2 * ar->ar_hln + 2 * ar->ar_pln;
    946 			break;
    947 		}
    948 		m_put_rcvif(rcvif, &s);
    949 
    950 		if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */
    951 		    m->m_len >= arplen)
    952 			switch (ntohs(ar->ar_pro)) {
    953 			case ETHERTYPE_IP:
    954 			case ETHERTYPE_IPTRAILERS:
    955 				in_arpinput(m);
    956 				continue;
    957 			default:
    958 				ARP_STATINC(ARP_STAT_RCVBADPROTO);
    959 			}
    960 		else {
    961 badlen:
    962 			ARP_STATINC(ARP_STAT_RCVBADLEN);
    963 		}
    964 		m_freem(m);
    965 	}
    966 	KERNEL_UNLOCK_ONE(NULL);
    967 	mutex_exit(softnet_lock);
    968 }
    969 
    970 /*
    971  * ARP for Internet protocols on 10 Mb/s Ethernet.
    972  * Algorithm is that given in RFC 826.
    973  * In addition, a sanity check is performed on the sender
    974  * protocol address, to catch impersonators.
    975  * We no longer handle negotiations for use of trailer protocol:
    976  * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
    977  * along with IP replies if we wanted trailers sent to us,
    978  * and also sent them in response to IP replies.
    979  * This allowed either end to announce the desire to receive
    980  * trailer packets.
    981  * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
    982  * but formerly didn't normally send requests.
    983  */
    984 static void
    985 in_arpinput(struct mbuf *m)
    986 {
    987 	struct arphdr *ah;
    988 	struct ifnet *ifp, *rcvif = NULL;
    989 	struct llentry *la = NULL;
    990 	struct in_ifaddr *ia = NULL;
    991 #if NBRIDGE > 0
    992 	struct in_ifaddr *bridge_ia = NULL;
    993 #endif
    994 #if NCARP > 0
    995 	u_int32_t count = 0, index = 0;
    996 #endif
    997 	struct sockaddr sa;
    998 	struct in_addr isaddr, itaddr, myaddr;
    999 	int op;
   1000 	void *tha;
   1001 	uint64_t *arps;
   1002 	struct psref psref, psref_ia;
   1003 	int s;
   1004 
   1005 	if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT)))
   1006 		goto out;
   1007 	ah = mtod(m, struct arphdr *);
   1008 	op = ntohs(ah->ar_op);
   1009 
   1010 	rcvif = ifp = m_get_rcvif_psref(m, &psref);
   1011 	if (__predict_false(rcvif == NULL))
   1012 		goto drop;
   1013 	/*
   1014 	 * Fix up ah->ar_hrd if necessary, before using ar_tha() or
   1015 	 * ar_tpa().
   1016 	 */
   1017 	switch (ifp->if_type) {
   1018 	case IFT_IEEE1394:
   1019 		if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394)
   1020 			;
   1021 		else {
   1022 			/* XXX this is to make sure we compute ar_tha right */
   1023 			/* XXX check ar_hrd more strictly? */
   1024 			ah->ar_hrd = htons(ARPHRD_IEEE1394);
   1025 		}
   1026 		break;
   1027 	default:
   1028 		/* XXX check ar_hrd? */
   1029 		break;
   1030 	}
   1031 
   1032 	memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
   1033 	memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
   1034 
   1035 	if (m->m_flags & (M_BCAST|M_MCAST))
   1036 		ARP_STATINC(ARP_STAT_RCVMCAST);
   1037 
   1038 
   1039 	/*
   1040 	 * Search for a matching interface address
   1041 	 * or any address on the interface to use
   1042 	 * as a dummy address in the rest of this function
   1043 	 */
   1044 	s = pserialize_read_enter();
   1045 	IN_ADDRHASH_READER_FOREACH(ia, itaddr.s_addr) {
   1046 		if (!in_hosteq(ia->ia_addr.sin_addr, itaddr))
   1047 			continue;
   1048 #if NCARP > 0
   1049 		if (ia->ia_ifp->if_type == IFT_CARP &&
   1050 		    ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) ==
   1051 		    (IFF_UP|IFF_RUNNING))) {
   1052 			index++;
   1053 			if (ia->ia_ifp == rcvif &&
   1054 			    carp_iamatch(ia, ar_sha(ah),
   1055 			    &count, index)) {
   1056 				break;
   1057 			}
   1058 		} else
   1059 #endif
   1060 		if (ia->ia_ifp == rcvif)
   1061 			break;
   1062 #if NBRIDGE > 0
   1063 		/*
   1064 		 * If the interface we received the packet on
   1065 		 * is part of a bridge, check to see if we need
   1066 		 * to "bridge" the packet to ourselves at this
   1067 		 * layer.  Note we still prefer a perfect match,
   1068 		 * but allow this weaker match if necessary.
   1069 		 */
   1070 		if (rcvif->if_bridge != NULL &&
   1071 		    rcvif->if_bridge == ia->ia_ifp->if_bridge)
   1072 			bridge_ia = ia;
   1073 #endif /* NBRIDGE > 0 */
   1074 	}
   1075 
   1076 #if NBRIDGE > 0
   1077 	if (ia == NULL && bridge_ia != NULL) {
   1078 		ia = bridge_ia;
   1079 		m_put_rcvif_psref(rcvif, &psref);
   1080 		rcvif = NULL;
   1081 		/* FIXME */
   1082 		ifp = bridge_ia->ia_ifp;
   1083 	}
   1084 #endif
   1085 	if (ia != NULL)
   1086 		ia4_acquire(ia, &psref_ia);
   1087 	pserialize_read_exit(s);
   1088 
   1089 	if (ia == NULL) {
   1090 		ia = in_get_ia_on_iface_psref(isaddr, rcvif, &psref_ia);
   1091 		if (ia == NULL) {
   1092 			ia = in_get_ia_from_ifp_psref(ifp, &psref_ia);
   1093 			if (ia == NULL) {
   1094 				ARP_STATINC(ARP_STAT_RCVNOINT);
   1095 				goto out;
   1096 			}
   1097 		}
   1098 	}
   1099 
   1100 	myaddr = ia->ia_addr.sin_addr;
   1101 
   1102 	/* XXX checks for bridge case? */
   1103 	if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) {
   1104 		ARP_STATINC(ARP_STAT_RCVLOCALSHA);
   1105 		goto out;	/* it's from me, ignore it. */
   1106 	}
   1107 
   1108 	/* XXX checks for bridge case? */
   1109 	if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
   1110 		ARP_STATINC(ARP_STAT_RCVBCASTSHA);
   1111 		log(LOG_ERR,
   1112 		    "%s: arp: link address is broadcast for IP address %s!\n",
   1113 		    ifp->if_xname, in_fmtaddr(isaddr));
   1114 		goto out;
   1115 	}
   1116 
   1117 	/*
   1118 	 * If the source IP address is zero, this is an RFC 5227 ARP probe
   1119 	 */
   1120 	if (in_nullhost(isaddr))
   1121 		ARP_STATINC(ARP_STAT_RCVZEROSPA);
   1122 	else if (in_hosteq(isaddr, myaddr))
   1123 		ARP_STATINC(ARP_STAT_RCVLOCALSPA);
   1124 
   1125 	if (in_nullhost(itaddr))
   1126 		ARP_STATINC(ARP_STAT_RCVZEROTPA);
   1127 
   1128 	/* DAD check, RFC 5227 2.1.1, Probe Details */
   1129 	if (in_hosteq(isaddr, myaddr) ||
   1130 	    (in_nullhost(isaddr) && in_hosteq(itaddr, myaddr)))
   1131 	{
   1132 		/* If our address is tentative, mark it as duplicated */
   1133 		if (ia->ia4_flags & IN_IFF_TENTATIVE)
   1134 			arp_dad_duplicated((struct ifaddr *)ia);
   1135 		/* If our address is unuseable, don't reply */
   1136 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
   1137 			goto out;
   1138 	}
   1139 
   1140 	/*
   1141 	 * If the target IP address is zero, ignore the packet.
   1142 	 * This prevents the code below from tring to answer
   1143 	 * when we are using IP address zero (booting).
   1144 	 */
   1145 	if (in_nullhost(itaddr))
   1146 		goto out;
   1147 
   1148 	if (in_nullhost(isaddr))
   1149 		goto reply;
   1150 
   1151 	if (in_hosteq(isaddr, myaddr)) {
   1152 		log(LOG_ERR,
   1153 		   "duplicate IP address %s sent from link address %s\n",
   1154 		   in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln));
   1155 		itaddr = myaddr;
   1156 		goto reply;
   1157 	}
   1158 
   1159 	if (in_hosteq(itaddr, myaddr))
   1160 		la = arpcreate(ifp, m, &isaddr, NULL, 1);
   1161 	else
   1162 		la = arplookup(ifp, m, &isaddr, NULL, 1);
   1163 	if (la == NULL)
   1164 		goto reply;
   1165 
   1166 	if ((la->la_flags & LLE_VALID) &&
   1167 	    memcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
   1168 		if (la->la_flags & LLE_STATIC) {
   1169 			ARP_STATINC(ARP_STAT_RCVOVERPERM);
   1170 			if (!log_permanent_modify)
   1171 				goto out;
   1172 			log(LOG_INFO,
   1173 			    "%s tried to overwrite permanent arp info"
   1174 			    " for %s\n",
   1175 			    lla_snprintf(ar_sha(ah), ah->ar_hln),
   1176 			    in_fmtaddr(isaddr));
   1177 			goto out;
   1178 		} else if (la->lle_tbl->llt_ifp != ifp) {
   1179 			/* XXX should not happen? */
   1180 			ARP_STATINC(ARP_STAT_RCVOVERINT);
   1181 			if (!log_wrong_iface)
   1182 				goto out;
   1183 			log(LOG_INFO,
   1184 			    "%s on %s tried to overwrite "
   1185 			    "arp info for %s on %s\n",
   1186 			    lla_snprintf(ar_sha(ah), ah->ar_hln),
   1187 			    ifp->if_xname, in_fmtaddr(isaddr),
   1188 			    la->lle_tbl->llt_ifp->if_xname);
   1189 				goto out;
   1190 		} else {
   1191 			ARP_STATINC(ARP_STAT_RCVOVER);
   1192 			if (log_movements)
   1193 				log(LOG_INFO, "arp info overwritten "
   1194 				    "for %s by %s\n",
   1195 				    in_fmtaddr(isaddr),
   1196 				    lla_snprintf(ar_sha(ah),
   1197 				    ah->ar_hln));
   1198 		}
   1199 	}
   1200 
   1201 	/* XXX llentry should have addrlen? */
   1202 #if 0
   1203 	/*
   1204 	 * sanity check for the address length.
   1205 	 * XXX this does not work for protocols with variable address
   1206 	 * length. -is
   1207 	 */
   1208 	if (sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
   1209 		ARP_STATINC(ARP_STAT_RCVLENCHG);
   1210 		log(LOG_WARNING,
   1211 		    "arp from %s: new addr len %d, was %d\n",
   1212 		    in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen);
   1213 	}
   1214 #endif
   1215 
   1216 	if (ifp->if_addrlen != ah->ar_hln) {
   1217 		ARP_STATINC(ARP_STAT_RCVBADLEN);
   1218 		log(LOG_WARNING,
   1219 		    "arp from %s: addr len: new %d, i/f %d (ignored)\n",
   1220 		    in_fmtaddr(isaddr), ah->ar_hln,
   1221 		    ifp->if_addrlen);
   1222 		goto reply;
   1223 	}
   1224 
   1225 #if NTOKEN > 0
   1226 	/*
   1227 	 * XXX uses m_data and assumes the complete answer including
   1228 	 * XXX token-ring headers is in the same buf
   1229 	 */
   1230 	if (ifp->if_type == IFT_ISO88025) {
   1231 		struct token_header *trh;
   1232 
   1233 		trh = (struct token_header *)M_TRHSTART(m);
   1234 		if (trh->token_shost[0] & TOKEN_RI_PRESENT) {
   1235 			struct token_rif *rif;
   1236 			size_t riflen;
   1237 
   1238 			rif = TOKEN_RIF(trh);
   1239 			riflen = (ntohs(rif->tr_rcf) &
   1240 			    TOKEN_RCF_LEN_MASK) >> 8;
   1241 
   1242 			if (riflen > 2 &&
   1243 			    riflen < sizeof(struct token_rif) &&
   1244 			    (riflen & 1) == 0) {
   1245 				rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION);
   1246 				rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK);
   1247 				memcpy(TOKEN_RIF_LLE(la), rif, riflen);
   1248 			}
   1249 		}
   1250 	}
   1251 #endif /* NTOKEN > 0 */
   1252 
   1253 	KASSERT(sizeof(la->ll_addr) >= ifp->if_addrlen);
   1254 	(void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
   1255 	la->la_flags |= LLE_VALID;
   1256 	if ((la->la_flags & LLE_STATIC) == 0) {
   1257 		la->la_expire = time_uptime + arpt_keep;
   1258 		arp_settimer(la, arpt_keep);
   1259 	}
   1260 	la->la_asked = 0;
   1261 	/* rt->rt_flags &= ~RTF_REJECT; */
   1262 
   1263 	if (la->la_hold != NULL) {
   1264 		int n = la->la_numheld;
   1265 		struct mbuf *m_hold, *m_hold_next;
   1266 		struct sockaddr_in sin;
   1267 
   1268 		sockaddr_in_init(&sin, &la->r_l3addr.addr4, 0);
   1269 
   1270 		m_hold = la->la_hold;
   1271 		la->la_hold = NULL;
   1272 		la->la_numheld = 0;
   1273 		/*
   1274 		 * We have to unlock here because if_output would call
   1275 		 * arpresolve
   1276 		 */
   1277 		LLE_WUNLOCK(la);
   1278 		ARP_STATADD(ARP_STAT_DFRSENT, n);
   1279 		ARP_STATADD(ARP_STAT_DFRTOTAL, n);
   1280 		for (; m_hold != NULL; m_hold = m_hold_next) {
   1281 			m_hold_next = m_hold->m_nextpkt;
   1282 			m_hold->m_nextpkt = NULL;
   1283 			if_output_lock(ifp, ifp, m_hold, sintosa(&sin), NULL);
   1284 		}
   1285 	} else
   1286 		LLE_WUNLOCK(la);
   1287 	la = NULL;
   1288 
   1289 reply:
   1290 	if (la != NULL) {
   1291 		LLE_WUNLOCK(la);
   1292 		la = NULL;
   1293 	}
   1294 	if (op != ARPOP_REQUEST) {
   1295 		if (op == ARPOP_REPLY)
   1296 			ARP_STATINC(ARP_STAT_RCVREPLY);
   1297 		goto out;
   1298 	}
   1299 	ARP_STATINC(ARP_STAT_RCVREQUEST);
   1300 	if (in_hosteq(itaddr, myaddr)) {
   1301 		/* If our address is unuseable, don't reply */
   1302 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
   1303 			goto out;
   1304 		/* I am the target */
   1305 		tha = ar_tha(ah);
   1306 		if (tha)
   1307 			memcpy(tha, ar_sha(ah), ah->ar_hln);
   1308 		memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
   1309 	} else {
   1310 		/* Proxy ARP */
   1311 		struct llentry *lle = NULL;
   1312 		struct sockaddr_in sin;
   1313 #if NCARP > 0
   1314 		struct ifnet *_rcvif = m_get_rcvif(m, &s);
   1315 		if (ifp->if_type == IFT_CARP && _rcvif->if_type != IFT_CARP)
   1316 			goto out;
   1317 		m_put_rcvif(_rcvif, &s);
   1318 #endif
   1319 
   1320 		tha = ar_tha(ah);
   1321 
   1322 		sockaddr_in_init(&sin, &itaddr, 0);
   1323 
   1324 		IF_AFDATA_RLOCK(ifp);
   1325 		lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
   1326 		IF_AFDATA_RUNLOCK(ifp);
   1327 
   1328 		if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
   1329 			(void)memcpy(tha, ar_sha(ah), ah->ar_hln);
   1330 			(void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
   1331 			LLE_RUNLOCK(lle);
   1332 		} else {
   1333 			if (lle != NULL)
   1334 				LLE_RUNLOCK(lle);
   1335 			goto drop;
   1336 		}
   1337 	}
   1338 	ia4_release(ia, &psref_ia);
   1339 
   1340 	memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
   1341 	memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
   1342 	ah->ar_op = htons(ARPOP_REPLY);
   1343 	ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
   1344 	switch (ifp->if_type) {
   1345 	case IFT_IEEE1394:
   1346 		/*
   1347 		 * ieee1394 arp reply is broadcast
   1348 		 */
   1349 		m->m_flags &= ~M_MCAST;
   1350 		m->m_flags |= M_BCAST;
   1351 		m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln;
   1352 		break;
   1353 
   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 		arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl));
   1458 
   1459 		/*
   1460 		 * interface address is considered static entry
   1461 		 * because the output of the arp utility shows
   1462 		 * that L2 entry as permanent
   1463 		 */
   1464 		IF_AFDATA_WLOCK(ifp);
   1465 		lle = lla_create(LLTABLE(ifp), (LLE_IFADDR | LLE_STATIC),
   1466 				 (struct sockaddr *)IA_SIN(ifa));
   1467 		IF_AFDATA_WUNLOCK(ifp);
   1468 		if (lle == NULL)
   1469 			log(LOG_INFO, "%s: cannot create arp entry for"
   1470 			    " interface address\n", __func__);
   1471 		else {
   1472 			arp_init_llentry(ifp, lle);
   1473 			LLE_RUNLOCK(lle);
   1474 		}
   1475 	}
   1476 
   1477 	ifa->ifa_rtrequest = arp_rtrequest;
   1478 	ifa->ifa_flags |= RTF_CONNECTED;
   1479 
   1480 	/* ARP will handle DAD for this address. */
   1481 	if (ia->ia4_flags & IN_IFF_TRYTENTATIVE) {
   1482 		ia->ia4_flags |= IN_IFF_TENTATIVE;
   1483 		ia->ia_dad_start = arp_dad_start;
   1484 		ia->ia_dad_stop = arp_dad_stop;
   1485 	}
   1486 }
   1487 
   1488 TAILQ_HEAD(dadq_head, dadq);
   1489 struct dadq {
   1490 	TAILQ_ENTRY(dadq) dad_list;
   1491 	struct ifaddr *dad_ifa;
   1492 	int dad_count;		/* max ARP to send */
   1493 	int dad_arp_tcount;	/* # of trials to send ARP */
   1494 	int dad_arp_ocount;	/* ARP sent so far */
   1495 	int dad_arp_announce;	/* max ARP announcements */
   1496 	int dad_arp_acount;	/* # of announcements */
   1497 	struct callout dad_timer_ch;
   1498 };
   1499 MALLOC_JUSTDEFINE(M_IPARP, "ARP DAD", "ARP DAD Structure");
   1500 
   1501 static struct dadq_head dadq;
   1502 static int dad_init = 0;
   1503 static int dad_maxtry = 15;     /* max # of *tries* to transmit DAD packet */
   1504 static kmutex_t arp_dad_lock;
   1505 
   1506 static struct dadq *
   1507 arp_dad_find(struct ifaddr *ifa)
   1508 {
   1509 	struct dadq *dp;
   1510 
   1511 	KASSERT(mutex_owned(&arp_dad_lock));
   1512 
   1513 	TAILQ_FOREACH(dp, &dadq, dad_list) {
   1514 		if (dp->dad_ifa == ifa)
   1515 			return dp;
   1516 	}
   1517 	return NULL;
   1518 }
   1519 
   1520 static void
   1521 arp_dad_starttimer(struct dadq *dp, int ticks)
   1522 {
   1523 
   1524 	callout_reset(&dp->dad_timer_ch, ticks,
   1525 	    (void (*)(void *))arp_dad_timer, (void *)dp->dad_ifa);
   1526 }
   1527 
   1528 static void
   1529 arp_dad_stoptimer(struct dadq *dp)
   1530 {
   1531 
   1532 	callout_halt(&dp->dad_timer_ch, softnet_lock);
   1533 }
   1534 
   1535 static void
   1536 arp_dad_output(struct dadq *dp, struct ifaddr *ifa)
   1537 {
   1538 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1539 	struct ifnet *ifp = ifa->ifa_ifp;
   1540 	struct in_addr sip;
   1541 
   1542 	dp->dad_arp_tcount++;
   1543 	if ((ifp->if_flags & IFF_UP) == 0)
   1544 		return;
   1545 	if ((ifp->if_flags & IFF_RUNNING) == 0)
   1546 		return;
   1547 
   1548 	dp->dad_arp_tcount = 0;
   1549 	dp->dad_arp_ocount++;
   1550 
   1551 	memset(&sip, 0, sizeof(sip));
   1552 	arprequest(ifa->ifa_ifp, &sip, &ia->ia_addr.sin_addr,
   1553 	    CLLADDR(ifa->ifa_ifp->if_sadl));
   1554 }
   1555 
   1556 /*
   1557  * Start Duplicate Address Detection (DAD) for specified interface address.
   1558  */
   1559 static void
   1560 arp_dad_start(struct ifaddr *ifa)
   1561 {
   1562 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1563 	struct dadq *dp;
   1564 
   1565 	if (!dad_init) {
   1566 		TAILQ_INIT(&dadq);
   1567 		mutex_init(&arp_dad_lock, MUTEX_DEFAULT, IPL_NONE);
   1568 		dad_init++;
   1569 	}
   1570 
   1571 	/*
   1572 	 * If we don't need DAD, don't do it.
   1573 	 * - DAD is disabled (ip_dad_count == 0)
   1574 	 */
   1575 	if (!(ia->ia4_flags & IN_IFF_TENTATIVE)) {
   1576 		log(LOG_DEBUG,
   1577 		    "%s: called with non-tentative address %s(%s)\n", __func__,
   1578 		    in_fmtaddr(ia->ia_addr.sin_addr),
   1579 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1580 		return;
   1581 	}
   1582 	if (!ip_dad_count) {
   1583 		struct in_addr *ip = &IA_SIN(ifa)->sin_addr;
   1584 
   1585 		ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1586 		rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1587 		arprequest(ifa->ifa_ifp, ip, ip,
   1588 		    CLLADDR(ifa->ifa_ifp->if_sadl));
   1589 		return;
   1590 	}
   1591 	KASSERT(ifa->ifa_ifp != NULL);
   1592 	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
   1593 		return;
   1594 
   1595 	mutex_enter(&arp_dad_lock);
   1596 	if (arp_dad_find(ifa) != NULL) {
   1597 		mutex_exit(&arp_dad_lock);
   1598 		/* DAD already in progress */
   1599 		return;
   1600 	}
   1601 
   1602 	dp = malloc(sizeof(*dp), M_IPARP, M_NOWAIT);
   1603 	if (dp == NULL) {
   1604 		mutex_exit(&arp_dad_lock);
   1605 		log(LOG_ERR, "%s: memory allocation failed for %s(%s)\n",
   1606 		    __func__, in_fmtaddr(ia->ia_addr.sin_addr),
   1607 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1608 		return;
   1609 	}
   1610 	memset(dp, 0, sizeof(*dp));
   1611 	callout_init(&dp->dad_timer_ch, CALLOUT_MPSAFE);
   1612 
   1613 	/*
   1614 	 * Send ARP packet for DAD, ip_dad_count times.
   1615 	 * Note that we must delay the first transmission.
   1616 	 */
   1617 	dp->dad_ifa = ifa;
   1618 	ifaref(ifa);	/* just for safety */
   1619 	dp->dad_count = ip_dad_count;
   1620 	dp->dad_arp_announce = 0; /* Will be set when starting to announce */
   1621 	dp->dad_arp_acount = dp->dad_arp_ocount = dp->dad_arp_tcount = 0;
   1622 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
   1623 
   1624 	arplog((LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
   1625 	    in_fmtaddr(ia->ia_addr.sin_addr)));
   1626 
   1627 	arp_dad_starttimer(dp, cprng_fast32() % (PROBE_WAIT * hz));
   1628 
   1629 	mutex_exit(&arp_dad_lock);
   1630 }
   1631 
   1632 /*
   1633  * terminate DAD unconditionally.  used for address removals.
   1634  */
   1635 static void
   1636 arp_dad_stop(struct ifaddr *ifa)
   1637 {
   1638 	struct dadq *dp;
   1639 
   1640 	if (!dad_init)
   1641 		return;
   1642 
   1643 	mutex_enter(&arp_dad_lock);
   1644 	dp = arp_dad_find(ifa);
   1645 	if (dp == NULL) {
   1646 		mutex_exit(&arp_dad_lock);
   1647 		/* DAD wasn't started yet */
   1648 		return;
   1649 	}
   1650 
   1651 	/* Prevent the timer from running anymore. */
   1652 	TAILQ_REMOVE(&dadq, dp, dad_list);
   1653 	mutex_exit(&arp_dad_lock);
   1654 
   1655 	arp_dad_stoptimer(dp);
   1656 
   1657 	free(dp, M_IPARP);
   1658 	dp = NULL;
   1659 	ifafree(ifa);
   1660 }
   1661 
   1662 static void
   1663 arp_dad_timer(struct ifaddr *ifa)
   1664 {
   1665 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1666 	struct dadq *dp;
   1667 	struct in_addr *ip;
   1668 
   1669 	mutex_enter(softnet_lock);
   1670 	KERNEL_LOCK(1, NULL);
   1671 	mutex_enter(&arp_dad_lock);
   1672 
   1673 	/* Sanity check */
   1674 	if (ia == NULL) {
   1675 		log(LOG_ERR, "%s: called with null parameter\n", __func__);
   1676 		goto done;
   1677 	}
   1678 	dp = arp_dad_find(ifa);
   1679 	if (dp == NULL) {
   1680 		/* DAD seems to be stopping, so do nothing. */
   1681 		goto done;
   1682 	}
   1683 	if (ia->ia4_flags & IN_IFF_DUPLICATED) {
   1684 		log(LOG_ERR, "%s: called with duplicate address %s(%s)\n",
   1685 		    __func__, in_fmtaddr(ia->ia_addr.sin_addr),
   1686 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1687 		goto done;
   1688 	}
   1689 	if ((ia->ia4_flags & IN_IFF_TENTATIVE) == 0 && dp->dad_arp_acount == 0)
   1690 	{
   1691 		log(LOG_ERR, "%s: called with non-tentative address %s(%s)\n",
   1692 		    __func__, in_fmtaddr(ia->ia_addr.sin_addr),
   1693 		    ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
   1694 		goto done;
   1695 	}
   1696 
   1697 	/* timeouted with IFF_{RUNNING,UP} check */
   1698 	if (dp->dad_arp_tcount > dad_maxtry) {
   1699 		arplog((LOG_INFO, "%s: could not run DAD, driver problem?\n",
   1700 		    if_name(ifa->ifa_ifp)));
   1701 
   1702 		TAILQ_REMOVE(&dadq, dp, dad_list);
   1703 		free(dp, M_IPARP);
   1704 		dp = NULL;
   1705 		ifafree(ifa);
   1706 		goto done;
   1707 	}
   1708 
   1709 	/* Need more checks? */
   1710 	if (dp->dad_arp_ocount < dp->dad_count) {
   1711 		int adelay;
   1712 
   1713 		/*
   1714 		 * We have more ARP to go.  Send ARP packet for DAD.
   1715 		 */
   1716 		arp_dad_output(dp, ifa);
   1717 		if (dp->dad_arp_ocount < dp->dad_count)
   1718 			adelay = (PROBE_MIN * hz) +
   1719 			    (cprng_fast32() %
   1720 			    ((PROBE_MAX * hz) - (PROBE_MIN * hz)));
   1721 		else
   1722 			adelay = ANNOUNCE_WAIT * hz;
   1723 		arp_dad_starttimer(dp, adelay);
   1724 		goto done;
   1725 	} else if (dp->dad_arp_acount == 0) {
   1726 		/*
   1727 		 * We are done with DAD.
   1728 		 * No duplicate address found.
   1729 		 */
   1730 		ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1731 		rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1732 		arplog((LOG_DEBUG,
   1733 		    "%s: DAD complete for %s - no duplicates found\n",
   1734 		    if_name(ifa->ifa_ifp),
   1735 		    in_fmtaddr(ia->ia_addr.sin_addr)));
   1736 		dp->dad_arp_announce = ANNOUNCE_NUM;
   1737 		goto announce;
   1738 	} else if (dp->dad_arp_acount < dp->dad_arp_announce) {
   1739 announce:
   1740 		/*
   1741 		 * Announce the address.
   1742 		 */
   1743 		ip = &IA_SIN(ifa)->sin_addr;
   1744 		arprequest(ifa->ifa_ifp, ip, ip,
   1745 		    CLLADDR(ifa->ifa_ifp->if_sadl));
   1746 		dp->dad_arp_acount++;
   1747 		if (dp->dad_arp_acount < dp->dad_arp_announce) {
   1748 			arp_dad_starttimer(dp, ANNOUNCE_INTERVAL * hz);
   1749 			goto done;
   1750 		}
   1751 		arplog((LOG_DEBUG,
   1752 		    "%s: ARP announcement complete for %s\n",
   1753 		    if_name(ifa->ifa_ifp),
   1754 		    in_fmtaddr(ia->ia_addr.sin_addr)));
   1755 	}
   1756 
   1757 	TAILQ_REMOVE(&dadq, dp, dad_list);
   1758 	free(dp, M_IPARP);
   1759 	dp = NULL;
   1760 	ifafree(ifa);
   1761 
   1762 done:
   1763 	mutex_exit(&arp_dad_lock);
   1764 	KERNEL_UNLOCK_ONE(NULL);
   1765 	mutex_exit(softnet_lock);
   1766 }
   1767 
   1768 static void
   1769 arp_dad_duplicated(struct ifaddr *ifa)
   1770 {
   1771 	struct in_ifaddr *ia = (struct in_ifaddr *)ifa;
   1772 	struct ifnet *ifp;
   1773 	struct dadq *dp;
   1774 
   1775 	mutex_enter(&arp_dad_lock);
   1776 	dp = arp_dad_find(ifa);
   1777 	if (dp == NULL) {
   1778 		mutex_exit(&arp_dad_lock);
   1779 		/* DAD seems to be stopping, so do nothing. */
   1780 		return;
   1781 	}
   1782 
   1783 	ifp = ifa->ifa_ifp;
   1784 	log(LOG_ERR,
   1785 	    "%s: DAD detected duplicate IPv4 address %s: ARP out=%d\n",
   1786 	    if_name(ifp), in_fmtaddr(ia->ia_addr.sin_addr),
   1787 	    dp->dad_arp_ocount);
   1788 
   1789 	ia->ia4_flags &= ~IN_IFF_TENTATIVE;
   1790 	ia->ia4_flags |= IN_IFF_DUPLICATED;
   1791 
   1792 	/* We are done with DAD, with duplicated address found. (failure) */
   1793 	arp_dad_stoptimer(dp);
   1794 
   1795 	/* Inform the routing socket that DAD has completed */
   1796 	rt_newaddrmsg(RTM_NEWADDR, ifa, 0, NULL);
   1797 
   1798 	TAILQ_REMOVE(&dadq, dp, dad_list);
   1799 	mutex_exit(&arp_dad_lock);
   1800 
   1801 	free(dp, M_IPARP);
   1802 	dp = NULL;
   1803 	ifafree(ifa);
   1804 }
   1805 
   1806 /*
   1807  * Called from 10 Mb/s Ethernet interrupt handlers
   1808  * when ether packet type ETHERTYPE_REVARP
   1809  * is received.  Common length and type checks are done here,
   1810  * then the protocol-specific routine is called.
   1811  */
   1812 void
   1813 revarpinput(struct mbuf *m)
   1814 {
   1815 	struct arphdr *ar;
   1816 
   1817 	if (m->m_len < sizeof(struct arphdr))
   1818 		goto out;
   1819 	ar = mtod(m, struct arphdr *);
   1820 #if 0 /* XXX I don't think we need this... and it will prevent other LL */
   1821 	if (ntohs(ar->ar_hrd) != ARPHRD_ETHER)
   1822 		goto out;
   1823 #endif
   1824 	if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
   1825 		goto out;
   1826 	switch (ntohs(ar->ar_pro)) {
   1827 	case ETHERTYPE_IP:
   1828 	case ETHERTYPE_IPTRAILERS:
   1829 		in_revarpinput(m);
   1830 		return;
   1831 
   1832 	default:
   1833 		break;
   1834 	}
   1835 out:
   1836 	m_freem(m);
   1837 }
   1838 
   1839 /*
   1840  * RARP for Internet protocols on 10 Mb/s Ethernet.
   1841  * Algorithm is that given in RFC 903.
   1842  * We are only using for bootstrap purposes to get an ip address for one of
   1843  * our interfaces.  Thus we support no user-interface.
   1844  *
   1845  * Since the contents of the RARP reply are specific to the interface that
   1846  * sent the request, this code must ensure that they are properly associated.
   1847  *
   1848  * Note: also supports ARP via RARP packets, per the RFC.
   1849  */
   1850 void
   1851 in_revarpinput(struct mbuf *m)
   1852 {
   1853 	struct arphdr *ah;
   1854 	void *tha;
   1855 	int op;
   1856 	struct ifnet *rcvif;
   1857 	int s;
   1858 
   1859 	ah = mtod(m, struct arphdr *);
   1860 	op = ntohs(ah->ar_op);
   1861 
   1862 	rcvif = m_get_rcvif(m, &s);
   1863 	switch (rcvif->if_type) {
   1864 	case IFT_IEEE1394:
   1865 		/* ARP without target hardware address is not supported */
   1866 		goto out;
   1867 	default:
   1868 		break;
   1869 	}
   1870 
   1871 	switch (op) {
   1872 	case ARPOP_REQUEST:
   1873 	case ARPOP_REPLY:	/* per RFC */
   1874 		m_put_rcvif(rcvif, &s);
   1875 		in_arpinput(m);
   1876 		return;
   1877 	case ARPOP_REVREPLY:
   1878 		break;
   1879 	case ARPOP_REVREQUEST:	/* handled by rarpd(8) */
   1880 	default:
   1881 		goto out;
   1882 	}
   1883 	if (!revarp_in_progress)
   1884 		goto out;
   1885 	if (rcvif != myip_ifp) /* !same interface */
   1886 		goto out;
   1887 	if (myip_initialized)
   1888 		goto wake;
   1889 	tha = ar_tha(ah);
   1890 	if (tha == NULL)
   1891 		goto out;
   1892 	if (memcmp(tha, CLLADDR(rcvif->if_sadl), rcvif->if_sadl->sdl_alen))
   1893 		goto out;
   1894 	memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip));
   1895 	memcpy(&myip, ar_tpa(ah), sizeof(myip));
   1896 	myip_initialized = 1;
   1897 wake:	/* Do wakeup every time in case it was missed. */
   1898 	wakeup((void *)&myip);
   1899 
   1900 out:
   1901 	m_put_rcvif(rcvif, &s);
   1902 	m_freem(m);
   1903 }
   1904 
   1905 /*
   1906  * Send a RARP request for the ip address of the specified interface.
   1907  * The request should be RFC 903-compliant.
   1908  */
   1909 static void
   1910 revarprequest(struct ifnet *ifp)
   1911 {
   1912 	struct sockaddr sa;
   1913 	struct mbuf *m;
   1914 	struct arphdr *ah;
   1915 	void *tha;
   1916 
   1917 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
   1918 		return;
   1919 	MCLAIM(m, &arpdomain.dom_mowner);
   1920 	m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
   1921 	    2*ifp->if_addrlen;
   1922 	m->m_pkthdr.len = m->m_len;
   1923 	MH_ALIGN(m, m->m_len);
   1924 	ah = mtod(m, struct arphdr *);
   1925 	memset(ah, 0, m->m_len);
   1926 	ah->ar_pro = htons(ETHERTYPE_IP);
   1927 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
   1928 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
   1929 	ah->ar_op = htons(ARPOP_REVREQUEST);
   1930 
   1931 	memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln);
   1932 	tha = ar_tha(ah);
   1933 	if (tha == NULL) {
   1934 		m_free(m);
   1935 		return;
   1936 	}
   1937 	memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln);
   1938 
   1939 	sa.sa_family = AF_ARP;
   1940 	sa.sa_len = 2;
   1941 	m->m_flags |= M_BCAST;
   1942 
   1943 	if_output_lock(ifp, ifp, m, &sa, NULL);
   1944 }
   1945 
   1946 /*
   1947  * RARP for the ip address of the specified interface, but also
   1948  * save the ip address of the server that sent the answer.
   1949  * Timeout if no response is received.
   1950  */
   1951 int
   1952 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in,
   1953     struct in_addr *clnt_in)
   1954 {
   1955 	int result, count = 20;
   1956 
   1957 	myip_initialized = 0;
   1958 	myip_ifp = ifp;
   1959 
   1960 	revarp_in_progress = 1;
   1961 	while (count--) {
   1962 		revarprequest(ifp);
   1963 		result = tsleep((void *)&myip, PSOCK, "revarp", hz/2);
   1964 		if (result != EWOULDBLOCK)
   1965 			break;
   1966 	}
   1967 	revarp_in_progress = 0;
   1968 
   1969 	if (!myip_initialized)
   1970 		return ENETUNREACH;
   1971 
   1972 	memcpy(serv_in, &srv_ip, sizeof(*serv_in));
   1973 	memcpy(clnt_in, &myip, sizeof(*clnt_in));
   1974 	return 0;
   1975 }
   1976 
   1977 void
   1978 arp_stat_add(int type, uint64_t count)
   1979 {
   1980 	ARP_STATADD(type, count);
   1981 }
   1982 
   1983 static int
   1984 sysctl_net_inet_arp_stats(SYSCTLFN_ARGS)
   1985 {
   1986 
   1987 	return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS);
   1988 }
   1989 
   1990 static void
   1991 sysctl_net_inet_arp_setup(struct sysctllog **clog)
   1992 {
   1993 	const struct sysctlnode *node;
   1994 
   1995 	sysctl_createv(clog, 0, NULL, NULL,
   1996 			CTLFLAG_PERMANENT,
   1997 			CTLTYPE_NODE, "inet", NULL,
   1998 			NULL, 0, NULL, 0,
   1999 			CTL_NET, PF_INET, CTL_EOL);
   2000 	sysctl_createv(clog, 0, NULL, &node,
   2001 			CTLFLAG_PERMANENT,
   2002 			CTLTYPE_NODE, "arp",
   2003 			SYSCTL_DESCR("Address Resolution Protocol"),
   2004 			NULL, 0, NULL, 0,
   2005 			CTL_NET, PF_INET, CTL_CREATE, CTL_EOL);
   2006 
   2007 	sysctl_createv(clog, 0, NULL, NULL,
   2008 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2009 			CTLTYPE_INT, "keep",
   2010 			SYSCTL_DESCR("Valid ARP entry lifetime in seconds"),
   2011 			NULL, 0, &arpt_keep, 0,
   2012 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2013 
   2014 	sysctl_createv(clog, 0, NULL, NULL,
   2015 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2016 			CTLTYPE_INT, "down",
   2017 			SYSCTL_DESCR("Failed ARP entry lifetime in seconds"),
   2018 			NULL, 0, &arpt_down, 0,
   2019 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2020 
   2021 	sysctl_createv(clog, 0, NULL, NULL,
   2022 			CTLFLAG_PERMANENT,
   2023 			CTLTYPE_STRUCT, "stats",
   2024 			SYSCTL_DESCR("ARP statistics"),
   2025 			sysctl_net_inet_arp_stats, 0, NULL, 0,
   2026 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2027 
   2028 	sysctl_createv(clog, 0, NULL, NULL,
   2029 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2030 			CTLTYPE_INT, "log_movements",
   2031 			SYSCTL_DESCR("log ARP replies from MACs different than"
   2032 			    " the one in the cache"),
   2033 			NULL, 0, &log_movements, 0,
   2034 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2035 
   2036 	sysctl_createv(clog, 0, NULL, NULL,
   2037 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2038 			CTLTYPE_INT, "log_permanent_modify",
   2039 			SYSCTL_DESCR("log ARP replies from MACs different than"
   2040 			    " the one in the permanent arp entry"),
   2041 			NULL, 0, &log_permanent_modify, 0,
   2042 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2043 
   2044 	sysctl_createv(clog, 0, NULL, NULL,
   2045 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2046 			CTLTYPE_INT, "log_wrong_iface",
   2047 			SYSCTL_DESCR("log ARP packets arriving on the wrong"
   2048 			    " interface"),
   2049 			NULL, 0, &log_wrong_iface, 0,
   2050 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2051 
   2052 	sysctl_createv(clog, 0, NULL, NULL,
   2053 			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2054 			CTLTYPE_INT, "log_unknown_network",
   2055 			SYSCTL_DESCR("log ARP packets from non-local network"),
   2056 			NULL, 0, &log_unknown_network, 0,
   2057 			CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2058 
   2059 	sysctl_createv(clog, 0, NULL, NULL,
   2060 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   2061 		       CTLTYPE_INT, "debug",
   2062 		       SYSCTL_DESCR("Enable ARP DAD debug output"),
   2063 		       NULL, 0, &arp_debug, 0,
   2064 		       CTL_NET, PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL);
   2065 }
   2066 
   2067 #endif /* INET */
   2068