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if_arp.c revision 1.96
      1 /*	$NetBSD: if_arp.c,v 1.96 2004/04/22 01:01:40 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998, 2000 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  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the NetBSD
     22  *	Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 /*
     41  * Copyright (c) 1982, 1986, 1988, 1993
     42  *	The Regents of the University of California.  All rights reserved.
     43  *
     44  * Redistribution and use in source and binary forms, with or without
     45  * modification, are permitted provided that the following conditions
     46  * are met:
     47  * 1. Redistributions of source code must retain the above copyright
     48  *    notice, this list of conditions and the following disclaimer.
     49  * 2. Redistributions in binary form must reproduce the above copyright
     50  *    notice, this list of conditions and the following disclaimer in the
     51  *    documentation and/or other materials provided with the distribution.
     52  * 3. Neither the name of the University nor the names of its contributors
     53  *    may be used to endorse or promote products derived from this software
     54  *    without specific prior written permission.
     55  *
     56  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     57  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     58  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     59  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     60  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     61  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     62  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     63  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     64  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     65  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     66  * SUCH DAMAGE.
     67  *
     68  *	@(#)if_ether.c	8.2 (Berkeley) 9/26/94
     69  */
     70 
     71 /*
     72  * Ethernet address resolution protocol.
     73  * TODO:
     74  *	add "inuse/lock" bit (or ref. count) along with valid bit
     75  */
     76 
     77 #include <sys/cdefs.h>
     78 __KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.96 2004/04/22 01:01:40 matt Exp $");
     79 
     80 #include "opt_ddb.h"
     81 #include "opt_inet.h"
     82 
     83 #ifdef INET
     84 
     85 #include "bridge.h"
     86 
     87 #include <sys/param.h>
     88 #include <sys/systm.h>
     89 #include <sys/callout.h>
     90 #include <sys/malloc.h>
     91 #include <sys/mbuf.h>
     92 #include <sys/socket.h>
     93 #include <sys/time.h>
     94 #include <sys/kernel.h>
     95 #include <sys/errno.h>
     96 #include <sys/ioctl.h>
     97 #include <sys/syslog.h>
     98 #include <sys/proc.h>
     99 #include <sys/protosw.h>
    100 #include <sys/domain.h>
    101 
    102 #include <net/ethertypes.h>
    103 #include <net/if.h>
    104 #include <net/if_dl.h>
    105 #include <net/if_token.h>
    106 #include <net/if_types.h>
    107 #include <net/route.h>
    108 
    109 #include <netinet/in.h>
    110 #include <netinet/in_systm.h>
    111 #include <netinet/in_var.h>
    112 #include <netinet/ip.h>
    113 #include <netinet/if_inarp.h>
    114 
    115 #include "loop.h"
    116 #include "arc.h"
    117 #if NARC > 0
    118 #include <net/if_arc.h>
    119 #endif
    120 #include "fddi.h"
    121 #if NFDDI > 0
    122 #include <net/if_fddi.h>
    123 #endif
    124 #include "token.h"
    125 
    126 #define SIN(s) ((struct sockaddr_in *)s)
    127 #define SDL(s) ((struct sockaddr_dl *)s)
    128 #define SRP(s) ((struct sockaddr_inarp *)s)
    129 
    130 /*
    131  * ARP trailer negotiation.  Trailer protocol is not IP specific,
    132  * but ARP request/response use IP addresses.
    133  */
    134 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
    135 
    136 /* timer values */
    137 int	arpt_prune = (5*60*1);	/* walk list every 5 minutes */
    138 int	arpt_keep = (20*60);	/* once resolved, good for 20 more minutes */
    139 int	arpt_down = 20;		/* once declared down, don't send for 20 secs */
    140 #define	rt_expire rt_rmx.rmx_expire
    141 
    142 extern	struct domain arpdomain;
    143 
    144 static	void arprequest __P((struct ifnet *,
    145 	    struct in_addr *, struct in_addr *, u_int8_t *));
    146 static	void arptfree __P((struct llinfo_arp *));
    147 static	void arptimer __P((void *));
    148 static	struct llinfo_arp *arplookup __P((struct mbuf *, struct in_addr *,
    149 					  int, int));
    150 static	void in_arpinput __P((struct mbuf *));
    151 
    152 #if NLOOP > 0
    153 extern	struct ifnet loif[NLOOP];
    154 #endif
    155 LIST_HEAD(, llinfo_arp) llinfo_arp;
    156 struct	ifqueue arpintrq = {0, 0, 0, 50};
    157 int	arp_inuse, arp_allocated, arp_intimer;
    158 int	arp_maxtries = 5;
    159 int	useloopback = 1;	/* use loopback interface for local traffic */
    160 int	arpinit_done = 0;
    161 
    162 struct	arpstat arpstat;
    163 struct	callout arptimer_ch;
    164 
    165 
    166 /* revarp state */
    167 static struct	in_addr myip, srv_ip;
    168 static int	myip_initialized = 0;
    169 static int	revarp_in_progress = 0;
    170 static struct	ifnet *myip_ifp = NULL;
    171 
    172 #ifdef DDB
    173 static void db_print_sa __P((const struct sockaddr *));
    174 static void db_print_ifa __P((struct ifaddr *));
    175 static void db_print_llinfo __P((caddr_t));
    176 static int db_show_radix_node __P((struct radix_node *, void *));
    177 #endif
    178 
    179 /*
    180  * this should be elsewhere.
    181  */
    182 
    183 static char *
    184 lla_snprintf __P((u_int8_t *, int));
    185 
    186 static char *
    187 lla_snprintf(adrp, len)
    188 	u_int8_t *adrp;
    189 	int len;
    190 {
    191 #define NUMBUFS 3
    192 	static char buf[NUMBUFS][16*3];
    193 	static int bnum = 0;
    194 	static const char hexdigits[] = {
    195 	    '0','1','2','3','4','5','6','7',
    196 	    '8','9','a','b','c','d','e','f'
    197 	};
    198 
    199 	int i;
    200 	char *p;
    201 
    202 	p = buf[bnum];
    203 
    204 	*p++ = hexdigits[(*adrp)>>4];
    205 	*p++ = hexdigits[(*adrp++)&0xf];
    206 
    207 	for (i=1; i<len && i<16; i++) {
    208 		*p++ = ':';
    209 		*p++ = hexdigits[(*adrp)>>4];
    210 		*p++ = hexdigits[(*adrp++)&0xf];
    211 	}
    212 
    213 	*p = 0;
    214 	p = buf[bnum];
    215 	bnum = (bnum + 1) % NUMBUFS;
    216 	return p;
    217 }
    218 
    219 const struct protosw arpsw[] = {
    220 	{ 0, 0, 0, 0,
    221 	  0, 0, 0, 0,
    222 	  0,
    223 	  0, 0, 0, arp_drain,
    224 	}
    225 };
    226 
    227 
    228 struct domain arpdomain =
    229 { 	PF_ARP,  "arp", 0, 0, 0,
    230 	arpsw, &arpsw[sizeof(arpsw)/sizeof(arpsw[0])]
    231 };
    232 
    233 /*
    234  * ARP table locking.
    235  *
    236  * to prevent lossage vs. the arp_drain routine (which may be called at
    237  * any time, including in a device driver context), we do two things:
    238  *
    239  * 1) manipulation of la->la_hold is done at splnet() (for all of
    240  * about two instructions).
    241  *
    242  * 2) manipulation of the arp table's linked list is done under the
    243  * protection of the ARP_LOCK; if arp_drain() or arptimer is called
    244  * while the arp table is locked, we punt and try again later.
    245  */
    246 
    247 static int	arp_locked;
    248 static __inline int arp_lock_try __P((int));
    249 static __inline void arp_unlock __P((void));
    250 
    251 static __inline int
    252 arp_lock_try(int recurse)
    253 {
    254 	int s;
    255 
    256 	/*
    257 	 * Use splvm() -- we're blocking things that would cause
    258 	 * mbuf allocation.
    259 	 */
    260 	s = splvm();
    261 	if (!recurse && arp_locked) {
    262 		splx(s);
    263 		return (0);
    264 	}
    265 	arp_locked++;
    266 	splx(s);
    267 	return (1);
    268 }
    269 
    270 static __inline void
    271 arp_unlock()
    272 {
    273 	int s;
    274 
    275 	s = splvm();
    276 	arp_locked--;
    277 	splx(s);
    278 }
    279 
    280 #ifdef DIAGNOSTIC
    281 #define	ARP_LOCK(recurse)						\
    282 do {									\
    283 	if (arp_lock_try(recurse) == 0) {				\
    284 		printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \
    285 		panic("arp_lock");					\
    286 	}								\
    287 } while (/*CONSTCOND*/ 0)
    288 #define	ARP_LOCK_CHECK()						\
    289 do {									\
    290 	if (arp_locked == 0) {						\
    291 		printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \
    292 		panic("arp lock check");				\
    293 	}								\
    294 } while (/*CONSTCOND*/ 0)
    295 #else
    296 #define	ARP_LOCK(x)		(void) arp_lock_try(x)
    297 #define	ARP_LOCK_CHECK()	/* nothing */
    298 #endif
    299 
    300 #define	ARP_UNLOCK()		arp_unlock()
    301 
    302 /*
    303  * ARP protocol drain routine.  Called when memory is in short supply.
    304  * Called at splvm();
    305  */
    306 
    307 void
    308 arp_drain()
    309 {
    310 	struct llinfo_arp *la, *nla;
    311 	int count = 0;
    312 	struct mbuf *mold;
    313 
    314 	if (arp_lock_try(0) == 0) {
    315 		printf("arp_drain: locked; punting\n");
    316 		return;
    317 	}
    318 
    319 	for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) {
    320 		nla = LIST_NEXT(la, la_list);
    321 
    322 		mold = la->la_hold;
    323 		la->la_hold = 0;
    324 
    325 		if (mold) {
    326 			m_freem(mold);
    327 			count++;
    328 		}
    329 	}
    330 	ARP_UNLOCK();
    331 	arpstat.as_dfrdropped += count;
    332 }
    333 
    334 
    335 /*
    336  * Timeout routine.  Age arp_tab entries periodically.
    337  */
    338 /* ARGSUSED */
    339 static void
    340 arptimer(arg)
    341 	void *arg;
    342 {
    343 	int s;
    344 	struct llinfo_arp *la, *nla;
    345 
    346 	s = splsoftnet();
    347 
    348 	if (arp_lock_try(0) == 0) {
    349 		/* get it later.. */
    350 		splx(s);
    351 		return;
    352 	}
    353 
    354 	callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL);
    355 	for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) {
    356 		struct rtentry *rt = la->la_rt;
    357 
    358 		nla = LIST_NEXT(la, la_list);
    359 		if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
    360 			arptfree(la); /* timer has expired; clear */
    361 	}
    362 
    363 	ARP_UNLOCK();
    364 
    365 	splx(s);
    366 }
    367 
    368 /*
    369  * Parallel to llc_rtrequest.
    370  */
    371 void
    372 arp_rtrequest(req, rt, info)
    373 	int req;
    374 	struct rtentry *rt;
    375 	struct rt_addrinfo *info;
    376 {
    377 	struct sockaddr *gate = rt->rt_gateway;
    378 	struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
    379 	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
    380 	size_t allocsize;
    381 	struct mbuf *mold;
    382 	int s;
    383 	struct in_ifaddr *ia;
    384 	struct ifaddr *ifa;
    385 
    386 	if (!arpinit_done) {
    387 		arpinit_done = 1;
    388 		/*
    389 		 * We generate expiration times from time.tv_sec
    390 		 * so avoid accidently creating permanent routes.
    391 		 */
    392 		if (time.tv_sec == 0) {
    393 			time.tv_sec++;
    394 		}
    395 		callout_init(&arptimer_ch);
    396 		callout_reset(&arptimer_ch, hz, arptimer, NULL);
    397 	}
    398 
    399 	if ((rt->rt_flags & RTF_GATEWAY) != 0) {
    400 		if (req != RTM_ADD)
    401 			return;
    402 
    403 		/*
    404 		 * linklayers with particular link MTU limitation.
    405 		 */
    406 		switch(rt->rt_ifp->if_type) {
    407 #if NFDDI > 0
    408 		case IFT_FDDI:
    409 			if (rt->rt_ifp->if_mtu > FDDIIPMTU)
    410 				rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    411 			break;
    412 #endif
    413 #if NARC > 0
    414 		case IFT_ARCNET:
    415 		    {
    416 			int arcipifmtu;
    417 
    418 			if (rt->rt_ifp->if_flags & IFF_LINK0)
    419 				arcipifmtu = arc_ipmtu;
    420 			else
    421 				arcipifmtu = ARCMTU;
    422 			if (rt->rt_ifp->if_mtu > arcipifmtu)
    423 				rt->rt_rmx.rmx_mtu = arcipifmtu;
    424 			break;
    425 		    }
    426 #endif
    427 		}
    428 		return;
    429 	}
    430 
    431 	ARP_LOCK(1);		/* we may already be locked here. */
    432 
    433 	switch (req) {
    434 
    435 	case RTM_ADD:
    436 		/*
    437 		 * XXX: If this is a manually added route to interface
    438 		 * such as older version of routed or gated might provide,
    439 		 * restore cloning bit.
    440 		 */
    441 		if ((rt->rt_flags & RTF_HOST) == 0 &&
    442 		    SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
    443 			rt->rt_flags |= RTF_CLONING;
    444 		if (rt->rt_flags & RTF_CLONING) {
    445 			/*
    446 			 * Case 1: This route should come from a route to iface.
    447 			 */
    448 			rt_setgate(rt, rt_key(rt),
    449 					(struct sockaddr *)&null_sdl);
    450 			gate = rt->rt_gateway;
    451 			SDL(gate)->sdl_type = rt->rt_ifp->if_type;
    452 			SDL(gate)->sdl_index = rt->rt_ifp->if_index;
    453 			/*
    454 			 * Give this route an expiration time, even though
    455 			 * it's a "permanent" route, so that routes cloned
    456 			 * from it do not need their expiration time set.
    457 			 */
    458 			rt->rt_expire = time.tv_sec;
    459 			/*
    460 			 * linklayers with particular link MTU limitation.
    461 			 */
    462 			switch (rt->rt_ifp->if_type) {
    463 #if NFDDI > 0
    464 			case IFT_FDDI:
    465 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    466 				    (rt->rt_rmx.rmx_mtu > FDDIIPMTU ||
    467 				     (rt->rt_rmx.rmx_mtu == 0 &&
    468 				      rt->rt_ifp->if_mtu > FDDIIPMTU)))
    469 					rt->rt_rmx.rmx_mtu = FDDIIPMTU;
    470 				break;
    471 #endif
    472 #if NARC > 0
    473 			case IFT_ARCNET:
    474 			    {
    475 				int arcipifmtu;
    476 				if (rt->rt_ifp->if_flags & IFF_LINK0)
    477 					arcipifmtu = arc_ipmtu;
    478 				else
    479 					arcipifmtu = ARCMTU;
    480 
    481 				if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 &&
    482 				    (rt->rt_rmx.rmx_mtu > arcipifmtu ||
    483 				     (rt->rt_rmx.rmx_mtu == 0 &&
    484 				      rt->rt_ifp->if_mtu > arcipifmtu)))
    485 					rt->rt_rmx.rmx_mtu = arcipifmtu;
    486 				break;
    487 			    }
    488 #endif
    489 			}
    490 			break;
    491 		}
    492 		/* Announce a new entry if requested. */
    493 		if (rt->rt_flags & RTF_ANNOUNCE)
    494 			arprequest(rt->rt_ifp,
    495 			    &SIN(rt_key(rt))->sin_addr,
    496 			    &SIN(rt_key(rt))->sin_addr,
    497 			    (u_char *)LLADDR(SDL(gate)));
    498 		/*FALLTHROUGH*/
    499 	case RTM_RESOLVE:
    500 		if (gate->sa_family != AF_LINK ||
    501 		    gate->sa_len < sizeof(null_sdl)) {
    502 			log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
    503 			break;
    504 		}
    505 		SDL(gate)->sdl_type = rt->rt_ifp->if_type;
    506 		SDL(gate)->sdl_index = rt->rt_ifp->if_index;
    507 		if (la != 0)
    508 			break; /* This happens on a route change */
    509 		/*
    510 		 * Case 2:  This route may come from cloning, or a manual route
    511 		 * add with a LL address.
    512 		 */
    513 		switch (SDL(gate)->sdl_type) {
    514 #if NTOKEN > 0
    515 		case IFT_ISO88025:
    516 			allocsize = sizeof(*la) + sizeof(struct token_rif);
    517 			break;
    518 #endif /* NTOKEN > 0 */
    519 		default:
    520 			allocsize = sizeof(*la);
    521 		}
    522 		R_Malloc(la, struct llinfo_arp *, allocsize);
    523 		rt->rt_llinfo = (caddr_t)la;
    524 		if (la == 0) {
    525 			log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
    526 			break;
    527 		}
    528 		arp_inuse++, arp_allocated++;
    529 		Bzero(la, allocsize);
    530 		la->la_rt = rt;
    531 		rt->rt_flags |= RTF_LLINFO;
    532 		LIST_INSERT_HEAD(&llinfo_arp, la, la_list);
    533 
    534 		INADDR_TO_IA(SIN(rt_key(rt))->sin_addr, ia);
    535 		while (ia && ia->ia_ifp != rt->rt_ifp)
    536 			NEXT_IA_WITH_SAME_ADDR(ia);
    537 		if (ia) {
    538 			/*
    539 			 * This test used to be
    540 			 *	if (loif.if_flags & IFF_UP)
    541 			 * It allowed local traffic to be forced through
    542 			 * the hardware by configuring the loopback down.
    543 			 * However, it causes problems during network
    544 			 * configuration for boards that can't receive
    545 			 * packets they send.  It is now necessary to clear
    546 			 * "useloopback" and remove the route to force
    547 			 * traffic out to the hardware.
    548 			 *
    549 			 * In 4.4BSD, the above "if" statement checked
    550 			 * rt->rt_ifa against rt_key(rt).  It was changed
    551 			 * to the current form so that we can provide a
    552 			 * better support for multiple IPv4 addresses on a
    553 			 * interface.
    554 			 */
    555 			rt->rt_expire = 0;
    556 			Bcopy(LLADDR(rt->rt_ifp->if_sadl),
    557 			    LLADDR(SDL(gate)),
    558 			    SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
    559 #if NLOOP > 0
    560 			if (useloopback)
    561 				rt->rt_ifp = &loif[0];
    562 #endif
    563 			/*
    564 			 * make sure to set rt->rt_ifa to the interface
    565 			 * address we are using, otherwise we will have trouble
    566 			 * with source address selection.
    567 			 */
    568 			ifa = &ia->ia_ifa;
    569 			if (ifa != rt->rt_ifa) {
    570 				IFAFREE(rt->rt_ifa);
    571 				IFAREF(ifa);
    572 				rt->rt_ifa = ifa;
    573 			}
    574 		}
    575 		break;
    576 
    577 	case RTM_DELETE:
    578 		if (la == 0)
    579 			break;
    580 		arp_inuse--;
    581 		LIST_REMOVE(la, la_list);
    582 		rt->rt_llinfo = 0;
    583 		rt->rt_flags &= ~RTF_LLINFO;
    584 
    585 		s = splnet();
    586 		mold = la->la_hold;
    587 		la->la_hold = 0;
    588 		splx(s);
    589 
    590 		if (mold)
    591 			m_freem(mold);
    592 
    593 		Free((caddr_t)la);
    594 	}
    595 	ARP_UNLOCK();
    596 }
    597 
    598 /*
    599  * Broadcast an ARP request. Caller specifies:
    600  *	- arp header source ip address
    601  *	- arp header target ip address
    602  *	- arp header source ethernet address
    603  */
    604 static void
    605 arprequest(ifp, sip, tip, enaddr)
    606 	struct ifnet *ifp;
    607 	struct in_addr *sip, *tip;
    608 	u_int8_t *enaddr;
    609 {
    610 	struct mbuf *m;
    611 	struct arphdr *ah;
    612 	struct sockaddr sa;
    613 
    614 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    615 		return;
    616 	MCLAIM(m, &arpdomain.dom_mowner);
    617 	switch (ifp->if_type) {
    618 	case IFT_IEEE1394:
    619 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    620 		    ifp->if_addrlen;
    621 		break;
    622 	default:
    623 		m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
    624 		    2 * ifp->if_addrlen;
    625 		break;
    626 	}
    627 	m->m_pkthdr.len = m->m_len;
    628 	MH_ALIGN(m, m->m_len);
    629 	ah = mtod(m, struct arphdr *);
    630 	bzero((caddr_t)ah, m->m_len);
    631 	switch (ifp->if_type) {
    632 	case IFT_IEEE1394:	/* RFC2734 */
    633 		/* fill it now for ar_tpa computation */
    634 		ah->ar_hrd = htons(ARPHRD_IEEE1394);
    635 		break;
    636 	default:
    637 		/* ifp->if_output will fill ar_hrd */
    638 		break;
    639 	}
    640 	ah->ar_pro = htons(ETHERTYPE_IP);
    641 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
    642 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
    643 	ah->ar_op = htons(ARPOP_REQUEST);
    644 	bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
    645 	bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
    646 	bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
    647 	sa.sa_family = AF_ARP;
    648 	sa.sa_len = 2;
    649 	m->m_flags |= M_BCAST;
    650 	arpstat.as_sndtotal++;
    651 	arpstat.as_sndrequest++;
    652 	(*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
    653 }
    654 
    655 /*
    656  * Resolve an IP address into an ethernet address.  If success,
    657  * desten is filled in.  If there is no entry in arptab,
    658  * set one up and broadcast a request for the IP address.
    659  * Hold onto this mbuf and resend it once the address
    660  * is finally resolved.  A return value of 1 indicates
    661  * that desten has been filled in and the packet should be sent
    662  * normally; a 0 return indicates that the packet has been
    663  * taken over here, either now or for later transmission.
    664  */
    665 int
    666 arpresolve(ifp, rt, m, dst, desten)
    667 	struct ifnet *ifp;
    668 	struct rtentry *rt;
    669 	struct mbuf *m;
    670 	struct sockaddr *dst;
    671 	u_char *desten;
    672 {
    673 	struct llinfo_arp *la;
    674 	struct sockaddr_dl *sdl;
    675 	struct mbuf *mold;
    676 	int s;
    677 
    678 	if (rt)
    679 		la = (struct llinfo_arp *)rt->rt_llinfo;
    680 	else {
    681 		if ((la = arplookup(m, &SIN(dst)->sin_addr, 1, 0)) != NULL)
    682 			rt = la->la_rt;
    683 	}
    684 	if (la == 0 || rt == 0) {
    685 		arpstat.as_allocfail++;
    686 		log(LOG_DEBUG,
    687 		    "arpresolve: can't allocate llinfo on %s for %s\n",
    688 		    ifp->if_xname, in_fmtaddr(SIN(dst)->sin_addr));
    689 		m_freem(m);
    690 		return (0);
    691 	}
    692 	sdl = SDL(rt->rt_gateway);
    693 	/*
    694 	 * Check the address family and length is valid, the address
    695 	 * is resolved; otherwise, try to resolve.
    696 	 */
    697 	if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&
    698 	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
    699 		bcopy(LLADDR(sdl), desten,
    700 		    min(sdl->sdl_alen, ifp->if_addrlen));
    701 		return 1;
    702 	}
    703 	/*
    704 	 * There is an arptab entry, but no ethernet address
    705 	 * response yet.  Replace the held mbuf with this
    706 	 * latest one.
    707 	 */
    708 
    709 	arpstat.as_dfrtotal++;
    710 	s = splnet();
    711 	mold = la->la_hold;
    712 	la->la_hold = m;
    713 	splx(s);
    714 
    715 	if (mold) {
    716 		arpstat.as_dfrdropped++;
    717 		m_freem(mold);
    718 	}
    719 
    720 	/*
    721 	 * Re-send the ARP request when appropriate.
    722 	 */
    723 #ifdef	DIAGNOSTIC
    724 	if (rt->rt_expire == 0) {
    725 		/* This should never happen. (Should it? -gwr) */
    726 		printf("arpresolve: unresolved and rt_expire == 0\n");
    727 		/* Set expiration time to now (expired). */
    728 		rt->rt_expire = time.tv_sec;
    729 	}
    730 #endif
    731 	if (rt->rt_expire) {
    732 		rt->rt_flags &= ~RTF_REJECT;
    733 		if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {
    734 			rt->rt_expire = time.tv_sec;
    735 			if (la->la_asked++ < arp_maxtries)
    736 				arprequest(ifp,
    737 				    &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
    738 				    &SIN(dst)->sin_addr,
    739 				    LLADDR(ifp->if_sadl));
    740 			else {
    741 				rt->rt_flags |= RTF_REJECT;
    742 				rt->rt_expire += arpt_down;
    743 				la->la_asked = 0;
    744 			}
    745 		}
    746 	}
    747 	return (0);
    748 }
    749 
    750 /*
    751  * Common length and type checks are done here,
    752  * then the protocol-specific routine is called.
    753  */
    754 void
    755 arpintr()
    756 {
    757 	struct mbuf *m;
    758 	struct arphdr *ar;
    759 	int s;
    760 	int arplen;
    761 
    762 	while (arpintrq.ifq_head) {
    763 		s = splnet();
    764 		IF_DEQUEUE(&arpintrq, m);
    765 		splx(s);
    766 		if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
    767 			panic("arpintr");
    768 
    769 		MCLAIM(m, &arpdomain.dom_mowner);
    770 		arpstat.as_rcvtotal++;
    771 
    772 		/*
    773 		 * First, make sure we have at least struct arphdr.
    774 		 */
    775 		if (m->m_len < sizeof(struct arphdr) ||
    776 		    (ar = mtod(m, struct arphdr *)) == NULL)
    777 			goto badlen;
    778 
    779 		switch (m->m_pkthdr.rcvif->if_type) {
    780 		case IFT_IEEE1394:
    781 			arplen = sizeof(struct arphdr) +
    782 			    ar->ar_hln + 2 * ar->ar_pln;
    783 			break;
    784 		default:
    785 			arplen = sizeof(struct arphdr) +
    786 			    2 * ar->ar_hln + 2 * ar->ar_pln;
    787 			break;
    788 		}
    789 
    790 		if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */
    791 		    m->m_len >= arplen)
    792 			switch (ntohs(ar->ar_pro)) {
    793 			case ETHERTYPE_IP:
    794 			case ETHERTYPE_IPTRAILERS:
    795 				in_arpinput(m);
    796 				continue;
    797 			default:
    798 				arpstat.as_rcvbadproto++;
    799 			}
    800 		else {
    801 badlen:
    802 			arpstat.as_rcvbadlen++;
    803 		}
    804 		m_freem(m);
    805 	}
    806 }
    807 
    808 /*
    809  * ARP for Internet protocols on 10 Mb/s Ethernet.
    810  * Algorithm is that given in RFC 826.
    811  * In addition, a sanity check is performed on the sender
    812  * protocol address, to catch impersonators.
    813  * We no longer handle negotiations for use of trailer protocol:
    814  * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
    815  * along with IP replies if we wanted trailers sent to us,
    816  * and also sent them in response to IP replies.
    817  * This allowed either end to announce the desire to receive
    818  * trailer packets.
    819  * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
    820  * but formerly didn't normally send requests.
    821  */
    822 static void
    823 in_arpinput(m)
    824 	struct mbuf *m;
    825 {
    826 	struct arphdr *ah;
    827 	struct ifnet *ifp = m->m_pkthdr.rcvif;
    828 	struct llinfo_arp *la = 0;
    829 	struct rtentry  *rt;
    830 	struct in_ifaddr *ia;
    831 #if NBRIDGE > 0
    832 	struct in_ifaddr *bridge_ia = NULL;
    833 #endif
    834 	struct sockaddr_dl *sdl;
    835 	struct sockaddr sa;
    836 	struct in_addr isaddr, itaddr, myaddr;
    837 	int op;
    838 	struct mbuf *mold;
    839 	int s;
    840 
    841 	ah = mtod(m, struct arphdr *);
    842 	op = ntohs(ah->ar_op);
    843 
    844 	/*
    845 	 * Fix up ah->ar_hrd if necessary, before using ar_tha() or
    846 	 * ar_tpa().
    847 	 */
    848 	switch (ifp->if_type) {
    849 	case IFT_IEEE1394:
    850 		if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394)
    851 			;
    852 		else {
    853 			/* XXX this is to make sure we compute ar_tha right */
    854 			/* XXX check ar_hrd more strictly? */
    855 			ah->ar_hrd = htons(ARPHRD_IEEE1394);
    856 		}
    857 		break;
    858 	default:
    859 		/* XXX check ar_hrd? */
    860 		break;
    861 	}
    862 
    863 	bcopy((caddr_t)ar_spa(ah), (caddr_t)&isaddr, sizeof (isaddr));
    864 	bcopy((caddr_t)ar_tpa(ah), (caddr_t)&itaddr, sizeof (itaddr));
    865 
    866 	if (m->m_flags & (M_BCAST|M_MCAST))
    867 		arpstat.as_rcvmcast++;
    868 
    869 	/*
    870 	 * If the target IP address is zero, ignore the packet.
    871 	 * This prevents the code below from tring to answer
    872 	 * when we are using IP address zero (booting).
    873 	 */
    874 	if (in_nullhost(itaddr)) {
    875 		arpstat.as_rcvzerotpa++;
    876 		goto out;
    877 	}
    878 
    879 	/*
    880 	 * If the source IP address is zero, this is most likely a
    881 	 * confused host trying to use IP address zero. (Windoze?)
    882 	 * XXX: Should we bother trying to reply to these?
    883 	 */
    884 	if (in_nullhost(isaddr)) {
    885 		arpstat.as_rcvzerospa++;
    886 		goto out;
    887 	}
    888 
    889 	/*
    890 	 * Search for a matching interface address
    891 	 * or any address on the interface to use
    892 	 * as a dummy address in the rest of this function
    893 	 */
    894 	INADDR_TO_IA(itaddr, ia);
    895 	while (ia != NULL) {
    896 		if (ia->ia_ifp == m->m_pkthdr.rcvif)
    897 			break;
    898 
    899 #if NBRIDGE > 0
    900 		/*
    901 		 * If the interface we received the packet on
    902 		 * is part of a bridge, check to see if we need
    903 		 * to "bridge" the packet to ourselves at this
    904 		 * layer.  Note we still prefer a perfect match,
    905 		 * but allow this weaker match if necessary.
    906 		 */
    907 		if (m->m_pkthdr.rcvif->if_bridge != NULL &&
    908 		    m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge)
    909 			bridge_ia = ia;
    910 #endif /* NBRIDGE > 0 */
    911 
    912 		NEXT_IA_WITH_SAME_ADDR(ia);
    913 	}
    914 
    915 #if NBRIDGE > 0
    916 	if (ia == NULL && bridge_ia != NULL) {
    917 		ia = bridge_ia;
    918 		ifp = bridge_ia->ia_ifp;
    919 	}
    920 #endif
    921 
    922 	if (ia == NULL) {
    923 		INADDR_TO_IA(isaddr, ia);
    924 		while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif)
    925 			NEXT_IA_WITH_SAME_ADDR(ia);
    926 
    927 		if (ia == NULL) {
    928 			IFP_TO_IA(ifp, ia);
    929 			if (ia == NULL) {
    930 				arpstat.as_rcvnoint++;
    931 				goto out;
    932 			}
    933 		}
    934 	}
    935 
    936 	myaddr = ia->ia_addr.sin_addr;
    937 
    938 	/* XXX checks for bridge case? */
    939 	if (!bcmp((caddr_t)ar_sha(ah), LLADDR(ifp->if_sadl),
    940 	    ifp->if_addrlen)) {
    941 		arpstat.as_rcvlocalsha++;
    942 		goto out;	/* it's from me, ignore it. */
    943 	}
    944 
    945 	/* XXX checks for bridge case? */
    946 	if (!bcmp((caddr_t)ar_sha(ah), (caddr_t)ifp->if_broadcastaddr,
    947 	    ifp->if_addrlen)) {
    948 		arpstat.as_rcvbcastsha++;
    949 		log(LOG_ERR,
    950 		    "%s: arp: link address is broadcast for IP address %s!\n",
    951 		    ifp->if_xname, in_fmtaddr(isaddr));
    952 		goto out;
    953 	}
    954 
    955 	if (in_hosteq(isaddr, myaddr)) {
    956 		arpstat.as_rcvlocalspa++;
    957 		log(LOG_ERR,
    958 		   "duplicate IP address %s sent from link address %s\n",
    959 		   in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln));
    960 		itaddr = myaddr;
    961 		goto reply;
    962 	}
    963 	la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0);
    964 	if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
    965 		if (sdl->sdl_alen &&
    966 		    bcmp((caddr_t)ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
    967 			if (rt->rt_flags & RTF_STATIC) {
    968 				arpstat.as_rcvoverperm++;
    969 				log(LOG_INFO,
    970 				    "%s tried to overwrite permanent arp info"
    971 				    " for %s\n",
    972 				    lla_snprintf(ar_sha(ah), ah->ar_hln),
    973 				    in_fmtaddr(isaddr));
    974 				goto out;
    975 			} else if (rt->rt_ifp != ifp) {
    976 				arpstat.as_rcvoverint++;
    977 				log(LOG_INFO,
    978 				    "%s on %s tried to overwrite "
    979 				    "arp info for %s on %s\n",
    980 				    lla_snprintf(ar_sha(ah), ah->ar_hln),
    981 				    ifp->if_xname, in_fmtaddr(isaddr),
    982 				    rt->rt_ifp->if_xname);
    983 				    goto out;
    984 			} else {
    985 				arpstat.as_rcvover++;
    986 				log(LOG_INFO,
    987 				    "arp info overwritten for %s by %s\n",
    988 				    in_fmtaddr(isaddr),
    989 				    lla_snprintf(ar_sha(ah), ah->ar_hln));
    990 			}
    991 		}
    992 		/*
    993 		 * sanity check for the address length.
    994 		 * XXX this does not work for protocols with variable address
    995 		 * length. -is
    996 		 */
    997 		if (sdl->sdl_alen &&
    998 		    sdl->sdl_alen != ah->ar_hln) {
    999 			arpstat.as_rcvlenchg++;
   1000 			log(LOG_WARNING,
   1001 			    "arp from %s: new addr len %d, was %d",
   1002 			    in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen);
   1003 		}
   1004 		if (ifp->if_addrlen != ah->ar_hln) {
   1005 			arpstat.as_rcvbadlen++;
   1006 			log(LOG_WARNING,
   1007 			    "arp from %s: addr len: new %d, i/f %d (ignored)",
   1008 			    in_fmtaddr(isaddr), ah->ar_hln,
   1009 			    ifp->if_addrlen);
   1010 			goto reply;
   1011 		}
   1012 #if NTOKEN > 0
   1013 		/*
   1014 		 * XXX uses m_data and assumes the complete answer including
   1015 		 * XXX token-ring headers is in the same buf
   1016 		 */
   1017 		if (ifp->if_type == IFT_ISO88025) {
   1018 			struct token_header *trh;
   1019 
   1020 			trh = (struct token_header *)M_TRHSTART(m);
   1021 			if (trh->token_shost[0] & TOKEN_RI_PRESENT) {
   1022 				struct token_rif	*rif;
   1023 				size_t	riflen;
   1024 
   1025 				rif = TOKEN_RIF(trh);
   1026 				riflen = (ntohs(rif->tr_rcf) &
   1027 				    TOKEN_RCF_LEN_MASK) >> 8;
   1028 
   1029 				if (riflen > 2 &&
   1030 				    riflen < sizeof(struct token_rif) &&
   1031 				    (riflen & 1) == 0) {
   1032 					rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION);
   1033 					rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK);
   1034 					bcopy(rif, TOKEN_RIF(la), riflen);
   1035 				}
   1036 			}
   1037 		}
   1038 #endif /* NTOKEN > 0 */
   1039 		bcopy((caddr_t)ar_sha(ah), LLADDR(sdl),
   1040 		    sdl->sdl_alen = ah->ar_hln);
   1041 		if (rt->rt_expire)
   1042 			rt->rt_expire = time.tv_sec + arpt_keep;
   1043 		rt->rt_flags &= ~RTF_REJECT;
   1044 		la->la_asked = 0;
   1045 
   1046 		s = splnet();
   1047 		mold = la->la_hold;
   1048 		la->la_hold = 0;
   1049 		splx(s);
   1050 
   1051 		if (mold) {
   1052 			arpstat.as_dfrsent++;
   1053 			(*ifp->if_output)(ifp, mold, rt_key(rt), rt);
   1054 		}
   1055 	}
   1056 reply:
   1057 	if (op != ARPOP_REQUEST) {
   1058 		if (op == ARPOP_REPLY)
   1059 			arpstat.as_rcvreply++;
   1060 	out:
   1061 		m_freem(m);
   1062 		return;
   1063 	}
   1064 	arpstat.as_rcvrequest++;
   1065 	if (in_hosteq(itaddr, myaddr)) {
   1066 		/* I am the target */
   1067 		if (ar_tha(ah))
   1068 			bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah),
   1069 			    ah->ar_hln);
   1070 		bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln);
   1071 	} else {
   1072 		la = arplookup(m, &itaddr, 0, SIN_PROXY);
   1073 		if (la == 0)
   1074 			goto out;
   1075 		rt = la->la_rt;
   1076 		if (ar_tha(ah))
   1077 			bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah),
   1078 			    ah->ar_hln);
   1079 		sdl = SDL(rt->rt_gateway);
   1080 		bcopy(LLADDR(sdl), (caddr_t)ar_sha(ah), ah->ar_hln);
   1081 	}
   1082 
   1083 	bcopy((caddr_t)ar_spa(ah), (caddr_t)ar_tpa(ah), ah->ar_pln);
   1084 	bcopy((caddr_t)&itaddr, (caddr_t)ar_spa(ah), ah->ar_pln);
   1085 	ah->ar_op = htons(ARPOP_REPLY);
   1086 	ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
   1087 	switch (ifp->if_type) {
   1088 	case IFT_IEEE1394:
   1089 		/*
   1090 		 * ieee1394 arp reply is broadcast
   1091 		 */
   1092 		m->m_flags &= ~M_MCAST;
   1093 		m->m_flags |= M_BCAST;
   1094 		m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln;
   1095 		break;
   1096 
   1097 	default:
   1098 		m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */
   1099 		m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
   1100 		break;
   1101 	}
   1102 	m->m_pkthdr.len = m->m_len;
   1103 	sa.sa_family = AF_ARP;
   1104 	sa.sa_len = 2;
   1105 	arpstat.as_sndtotal++;
   1106 	arpstat.as_sndreply++;
   1107 	(*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
   1108 	return;
   1109 }
   1110 
   1111 /*
   1112  * Free an arp entry.
   1113  */
   1114 static void
   1115 arptfree(la)
   1116 	struct llinfo_arp *la;
   1117 {
   1118 	struct rtentry *rt = la->la_rt;
   1119 	struct sockaddr_dl *sdl;
   1120 
   1121 	ARP_LOCK_CHECK();
   1122 
   1123 	if (rt == 0)
   1124 		panic("arptfree");
   1125 	if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
   1126 	    sdl->sdl_family == AF_LINK) {
   1127 		sdl->sdl_alen = 0;
   1128 		la->la_asked = 0;
   1129 		rt->rt_flags &= ~RTF_REJECT;
   1130 		return;
   1131 	}
   1132 	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
   1133 	    0, (struct rtentry **)0);
   1134 }
   1135 
   1136 /*
   1137  * Lookup or enter a new address in arptab.
   1138  */
   1139 static struct llinfo_arp *
   1140 arplookup(m, addr, create, proxy)
   1141 	struct mbuf *m;
   1142 	struct in_addr *addr;
   1143 	int create, proxy;
   1144 {
   1145 	struct arphdr *ah;
   1146 	struct ifnet *ifp = m->m_pkthdr.rcvif;
   1147 	struct rtentry *rt;
   1148 	static struct sockaddr_inarp sin;
   1149 	const char *why = 0;
   1150 
   1151 	ah = mtod(m, struct arphdr *);
   1152 	sin.sin_len = sizeof(sin);
   1153 	sin.sin_family = AF_INET;
   1154 	sin.sin_addr = *addr;
   1155 	sin.sin_other = proxy ? SIN_PROXY : 0;
   1156 	rt = rtalloc1(sintosa(&sin), create);
   1157 	if (rt == 0)
   1158 		return (0);
   1159 	rt->rt_refcnt--;
   1160 
   1161 	if (rt->rt_flags & RTF_GATEWAY)
   1162 		why = "host is not on local network";
   1163 	else if ((rt->rt_flags & RTF_LLINFO) == 0) {
   1164 		arpstat.as_allocfail++;
   1165 		why = "could not allocate llinfo";
   1166 	} else if (rt->rt_gateway->sa_family != AF_LINK)
   1167 		why = "gateway route is not ours";
   1168 	else
   1169 		return ((struct llinfo_arp *)rt->rt_llinfo);
   1170 
   1171 	if (create) {
   1172 		log(LOG_DEBUG, "arplookup: unable to enter address"
   1173 		    " for %s@%s on %s (%s)\n",
   1174 		    in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln),
   1175 		    (ifp) ? ifp->if_xname : 0, why);
   1176 		if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) {
   1177 			rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
   1178 		    	    rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
   1179 		}
   1180 	}
   1181 	return (0);
   1182 }
   1183 
   1184 int
   1185 arpioctl(cmd, data)
   1186 	u_long cmd;
   1187 	caddr_t data;
   1188 {
   1189 
   1190 	return (EOPNOTSUPP);
   1191 }
   1192 
   1193 void
   1194 arp_ifinit(ifp, ifa)
   1195 	struct ifnet *ifp;
   1196 	struct ifaddr *ifa;
   1197 {
   1198 	struct in_addr *ip;
   1199 
   1200 	/*
   1201 	 * Warn the user if another station has this IP address,
   1202 	 * but only if the interface IP address is not zero.
   1203 	 */
   1204 	ip = &IA_SIN(ifa)->sin_addr;
   1205 	if (!in_nullhost(*ip))
   1206 		arprequest(ifp, ip, ip, LLADDR(ifp->if_sadl));
   1207 
   1208 	ifa->ifa_rtrequest = arp_rtrequest;
   1209 	ifa->ifa_flags |= RTF_CLONING;
   1210 }
   1211 
   1212 /*
   1213  * Called from 10 Mb/s Ethernet interrupt handlers
   1214  * when ether packet type ETHERTYPE_REVARP
   1215  * is received.  Common length and type checks are done here,
   1216  * then the protocol-specific routine is called.
   1217  */
   1218 void
   1219 revarpinput(m)
   1220 	struct mbuf *m;
   1221 {
   1222 	struct arphdr *ar;
   1223 
   1224 	if (m->m_len < sizeof(struct arphdr))
   1225 		goto out;
   1226 	ar = mtod(m, struct arphdr *);
   1227 #if 0 /* XXX I don't think we need this... and it will prevent other LL */
   1228 	if (ntohs(ar->ar_hrd) != ARPHRD_ETHER)
   1229 		goto out;
   1230 #endif
   1231 	if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
   1232 		goto out;
   1233 	switch (ntohs(ar->ar_pro)) {
   1234 	case ETHERTYPE_IP:
   1235 	case ETHERTYPE_IPTRAILERS:
   1236 		in_revarpinput(m);
   1237 		return;
   1238 
   1239 	default:
   1240 		break;
   1241 	}
   1242 out:
   1243 	m_freem(m);
   1244 }
   1245 
   1246 /*
   1247  * RARP for Internet protocols on 10 Mb/s Ethernet.
   1248  * Algorithm is that given in RFC 903.
   1249  * We are only using for bootstrap purposes to get an ip address for one of
   1250  * our interfaces.  Thus we support no user-interface.
   1251  *
   1252  * Since the contents of the RARP reply are specific to the interface that
   1253  * sent the request, this code must ensure that they are properly associated.
   1254  *
   1255  * Note: also supports ARP via RARP packets, per the RFC.
   1256  */
   1257 void
   1258 in_revarpinput(m)
   1259 	struct mbuf *m;
   1260 {
   1261 	struct ifnet *ifp;
   1262 	struct arphdr *ah;
   1263 	int op;
   1264 
   1265 	ah = mtod(m, struct arphdr *);
   1266 	op = ntohs(ah->ar_op);
   1267 
   1268 	switch (m->m_pkthdr.rcvif->if_type) {
   1269 	case IFT_IEEE1394:
   1270 		/* ARP without target hardware address is not supported */
   1271 		goto out;
   1272 	default:
   1273 		break;
   1274 	}
   1275 
   1276 	switch (op) {
   1277 	case ARPOP_REQUEST:
   1278 	case ARPOP_REPLY:	/* per RFC */
   1279 		in_arpinput(m);
   1280 		return;
   1281 	case ARPOP_REVREPLY:
   1282 		break;
   1283 	case ARPOP_REVREQUEST:	/* handled by rarpd(8) */
   1284 	default:
   1285 		goto out;
   1286 	}
   1287 	if (!revarp_in_progress)
   1288 		goto out;
   1289 	ifp = m->m_pkthdr.rcvif;
   1290 	if (ifp != myip_ifp) /* !same interface */
   1291 		goto out;
   1292 	if (myip_initialized)
   1293 		goto wake;
   1294 	if (bcmp(ar_tha(ah), LLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen))
   1295 		goto out;
   1296 	bcopy((caddr_t)ar_spa(ah), (caddr_t)&srv_ip, sizeof(srv_ip));
   1297 	bcopy((caddr_t)ar_tpa(ah), (caddr_t)&myip, sizeof(myip));
   1298 	myip_initialized = 1;
   1299 wake:	/* Do wakeup every time in case it was missed. */
   1300 	wakeup((caddr_t)&myip);
   1301 
   1302 out:
   1303 	m_freem(m);
   1304 }
   1305 
   1306 /*
   1307  * Send a RARP request for the ip address of the specified interface.
   1308  * The request should be RFC 903-compliant.
   1309  */
   1310 void
   1311 revarprequest(ifp)
   1312 	struct ifnet *ifp;
   1313 {
   1314 	struct sockaddr sa;
   1315 	struct mbuf *m;
   1316 	struct arphdr *ah;
   1317 
   1318 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
   1319 		return;
   1320 	MCLAIM(m, &arpdomain.dom_mowner);
   1321 	m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
   1322 	    2*ifp->if_addrlen;
   1323 	m->m_pkthdr.len = m->m_len;
   1324 	MH_ALIGN(m, m->m_len);
   1325 	ah = mtod(m, struct arphdr *);
   1326 	bzero((caddr_t)ah, m->m_len);
   1327 	ah->ar_pro = htons(ETHERTYPE_IP);
   1328 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
   1329 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
   1330 	ah->ar_op = htons(ARPOP_REVREQUEST);
   1331 
   1332 	bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln);
   1333 	bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_tha(ah), ah->ar_hln);
   1334 
   1335 	sa.sa_family = AF_ARP;
   1336 	sa.sa_len = 2;
   1337 	m->m_flags |= M_BCAST;
   1338 	(*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
   1339 
   1340 }
   1341 
   1342 /*
   1343  * RARP for the ip address of the specified interface, but also
   1344  * save the ip address of the server that sent the answer.
   1345  * Timeout if no response is received.
   1346  */
   1347 int
   1348 revarpwhoarewe(ifp, serv_in, clnt_in)
   1349 	struct ifnet *ifp;
   1350 	struct in_addr *serv_in;
   1351 	struct in_addr *clnt_in;
   1352 {
   1353 	int result, count = 20;
   1354 
   1355 	myip_initialized = 0;
   1356 	myip_ifp = ifp;
   1357 
   1358 	revarp_in_progress = 1;
   1359 	while (count--) {
   1360 		revarprequest(ifp);
   1361 		result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2);
   1362 		if (result != EWOULDBLOCK)
   1363 			break;
   1364 	}
   1365 	revarp_in_progress = 0;
   1366 
   1367 	if (!myip_initialized)
   1368 		return ENETUNREACH;
   1369 
   1370 	bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in));
   1371 	bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in));
   1372 	return 0;
   1373 }
   1374 
   1375 
   1376 
   1378 #ifdef DDB
   1379 
   1380 #include <machine/db_machdep.h>
   1381 #include <ddb/db_interface.h>
   1382 #include <ddb/db_output.h>
   1383 static void
   1384 db_print_sa(sa)
   1385 	const struct sockaddr *sa;
   1386 {
   1387 	int len;
   1388 	u_char *p;
   1389 
   1390 	if (sa == 0) {
   1391 		db_printf("[NULL]");
   1392 		return;
   1393 	}
   1394 
   1395 	p = (u_char*)sa;
   1396 	len = sa->sa_len;
   1397 	db_printf("[");
   1398 	while (len > 0) {
   1399 		db_printf("%d", *p);
   1400 		p++; len--;
   1401 		if (len) db_printf(",");
   1402 	}
   1403 	db_printf("]\n");
   1404 }
   1405 static void
   1406 db_print_ifa(ifa)
   1407 	struct ifaddr *ifa;
   1408 {
   1409 	if (ifa == 0)
   1410 		return;
   1411 	db_printf("  ifa_addr=");
   1412 	db_print_sa(ifa->ifa_addr);
   1413 	db_printf("  ifa_dsta=");
   1414 	db_print_sa(ifa->ifa_dstaddr);
   1415 	db_printf("  ifa_mask=");
   1416 	db_print_sa(ifa->ifa_netmask);
   1417 	db_printf("  flags=0x%x,refcnt=%d,metric=%d\n",
   1418 			  ifa->ifa_flags,
   1419 			  ifa->ifa_refcnt,
   1420 			  ifa->ifa_metric);
   1421 }
   1422 static void
   1423 db_print_llinfo(li)
   1424 	caddr_t li;
   1425 {
   1426 	struct llinfo_arp *la;
   1427 
   1428 	if (li == 0)
   1429 		return;
   1430 	la = (struct llinfo_arp *)li;
   1431 	db_printf("  la_rt=%p la_hold=%p, la_asked=0x%lx\n",
   1432 			  la->la_rt, la->la_hold, la->la_asked);
   1433 }
   1434 /*
   1435  * Function to pass to rn_walktree().
   1436  * Return non-zero error to abort walk.
   1437  */
   1438 static int
   1439 db_show_radix_node(rn, w)
   1440 	struct radix_node *rn;
   1441 	void *w;
   1442 {
   1443 	struct rtentry *rt = (struct rtentry *)rn;
   1444 
   1445 	db_printf("rtentry=%p", rt);
   1446 
   1447 	db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n",
   1448 			  rt->rt_flags, rt->rt_refcnt,
   1449 			  rt->rt_use, rt->rt_expire);
   1450 
   1451 	db_printf(" key="); db_print_sa(rt_key(rt));
   1452 	db_printf(" mask="); db_print_sa(rt_mask(rt));
   1453 	db_printf(" gw="); db_print_sa(rt->rt_gateway);
   1454 
   1455 	db_printf(" ifp=%p ", rt->rt_ifp);
   1456 	if (rt->rt_ifp)
   1457 		db_printf("(%s)", rt->rt_ifp->if_xname);
   1458 	else
   1459 		db_printf("(NULL)");
   1460 
   1461 	db_printf(" ifa=%p\n", rt->rt_ifa);
   1462 	db_print_ifa(rt->rt_ifa);
   1463 
   1464 	db_printf(" genmask="); db_print_sa(rt->rt_genmask);
   1465 
   1466 	db_printf(" gwroute=%p llinfo=%p\n",
   1467 			  rt->rt_gwroute, rt->rt_llinfo);
   1468 	db_print_llinfo(rt->rt_llinfo);
   1469 
   1470 	return (0);
   1471 }
   1472 /*
   1473  * Function to print all the route trees.
   1474  * Use this from ddb:  "show arptab"
   1475  */
   1476 void
   1477 db_show_arptab(addr, have_addr, count, modif)
   1478 	db_expr_t	addr;
   1479 	int		have_addr;
   1480 	db_expr_t	count;
   1481 	char *		modif;
   1482 {
   1483 	struct radix_node_head *rnh;
   1484 	rnh = rt_tables[AF_INET];
   1485 	db_printf("Route tree for AF_INET\n");
   1486 	if (rnh == NULL) {
   1487 		db_printf(" (not initialized)\n");
   1488 		return;
   1489 	}
   1490 	rn_walktree(rnh, db_show_radix_node, NULL);
   1491 	return;
   1492 }
   1493 #endif
   1494 #endif /* INET */
   1495