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aarp.c revision 1.12
      1 /*	$NetBSD: aarp.c,v 1.12 2003/02/26 07:53:04 matt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1990,1991 Regents of The University of Michigan.
      5  * All Rights Reserved.
      6  *
      7  * Permission to use, copy, modify, and distribute this software and
      8  * its documentation for any purpose and without fee is hereby granted,
      9  * provided that the above copyright notice appears in all copies and
     10  * that both that copyright notice and this permission notice appear
     11  * in supporting documentation, and that the name of The University
     12  * of Michigan not be used in advertising or publicity pertaining to
     13  * distribution of the software without specific, written prior
     14  * permission. This software is supplied as is without expressed or
     15  * implied warranties of any kind.
     16  *
     17  * This product includes software developed by the University of
     18  * California, Berkeley and its contributors.
     19  *
     20  *	Research Systems Unix Group
     21  *	The University of Michigan
     22  *	c/o Wesley Craig
     23  *	535 W. William Street
     24  *	Ann Arbor, Michigan
     25  *	+1-313-764-2278
     26  *	netatalk (at) umich.edu
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: aarp.c,v 1.12 2003/02/26 07:53:04 matt Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/socket.h>
     34 #include <sys/syslog.h>
     35 #include <sys/systm.h>
     36 #include <sys/callout.h>
     37 #include <sys/proc.h>
     38 #include <sys/mbuf.h>
     39 #include <sys/time.h>
     40 #include <sys/kernel.h>
     41 #include <net/if.h>
     42 #include <net/route.h>
     43 #include <net/if_ether.h>
     44 #include <net/if_dl.h>
     45 #include <netinet/in.h>
     46 #undef s_net
     47 
     48 #include <netatalk/at.h>
     49 #include <netatalk/at_var.h>
     50 #include <netatalk/aarp.h>
     51 #include <netatalk/ddp_var.h>
     52 #include <netatalk/phase2.h>
     53 #include <netatalk/at_extern.h>
     54 
     55 static struct aarptab *aarptnew __P((struct at_addr *));
     56 static void aarptfree __P((struct aarptab *));
     57 static void at_aarpinput __P((struct ifnet *, struct mbuf *));
     58 static void aarptimer __P((void *));
     59 static void aarpwhohas __P((struct ifnet *, struct sockaddr_at *));
     60 
     61 #define AARPTAB_BSIZ	9
     62 #define AARPTAB_NB	19
     63 #define AARPTAB_SIZE	(AARPTAB_BSIZ * AARPTAB_NB)
     64 struct aarptab  aarptab[AARPTAB_SIZE];
     65 
     66 #define AARPTAB_HASH(a) \
     67     ((((a).s_net << 8 ) + (a).s_node ) % AARPTAB_NB )
     68 
     69 #define AARPTAB_LOOK(aat,addr) { \
     70     int		n; \
     71     aat = &aarptab[ AARPTAB_HASH(addr) * AARPTAB_BSIZ ]; \
     72     for ( n = 0; n < AARPTAB_BSIZ; n++, aat++ ) \
     73 	if ( aat->aat_ataddr.s_net == (addr).s_net && \
     74 	     aat->aat_ataddr.s_node == (addr).s_node ) \
     75 	    break; \
     76 	if ( n >= AARPTAB_BSIZ ) \
     77 	    aat = 0; \
     78 }
     79 
     80 #define AARPT_AGE	(60 * 1)
     81 #define AARPT_KILLC	20
     82 #define AARPT_KILLI	3
     83 
     84 #if !defined( __FreeBSD__ )
     85 extern u_char   etherbroadcastaddr[6];
     86 #endif	/* __FreeBSD__ */
     87 
     88 const u_char atmulticastaddr[6] = {
     89 	0x09, 0x00, 0x07, 0xff, 0xff, 0xff
     90 };
     91 
     92 const u_char at_org_code[3] = {
     93 	0x08, 0x00, 0x07
     94 };
     95 const u_char aarp_org_code[3] = {
     96 	0x00, 0x00, 0x00
     97 };
     98 
     99 struct callout aarptimer_callout;
    100 #ifdef MBUFTRACE
    101 struct mowner aarp_mowner = { "atalk", "arp" };
    102 #endif
    103 
    104 /*ARGSUSED*/
    105 static void
    106 aarptimer(ignored)
    107 	void *ignored;
    108 {
    109 	struct aarptab *aat;
    110 	int             i, s;
    111 
    112 	callout_reset(&aarptimer_callout, AARPT_AGE * hz, aarptimer, NULL);
    113 	aat = aarptab;
    114 	for (i = 0; i < AARPTAB_SIZE; i++, aat++) {
    115 		int killtime = (aat->aat_flags & ATF_COM) ? AARPT_KILLC :
    116 		    AARPT_KILLI;
    117 		if (aat->aat_flags == 0 || (aat->aat_flags & ATF_PERM))
    118 			continue;
    119 		if (++aat->aat_timer < killtime)
    120 			continue;
    121 		s = splnet();
    122 		aarptfree(aat);
    123 		splx(s);
    124 	}
    125 }
    126 
    127 /*
    128  * search through the network addresses to find one that includes the given
    129  * network.. remember to take netranges into consideration.
    130  */
    131 struct ifaddr *
    132 at_ifawithnet(sat, ifp)
    133 	struct sockaddr_at *sat;
    134 	struct ifnet *ifp;
    135 {
    136 	struct ifaddr  *ifa;
    137 	struct sockaddr_at *sat2;
    138 	struct netrange *nr;
    139 
    140 	for (ifa = ifp->if_addrlist.tqh_first; ifa;
    141 	    ifa = ifa->ifa_list.tqe_next) {
    142 		if (ifa->ifa_addr->sa_family != AF_APPLETALK)
    143 			continue;
    144 
    145 		sat2 = satosat(ifa->ifa_addr);
    146 		if (sat2->sat_addr.s_net == sat->sat_addr.s_net)
    147 			break;
    148 
    149 		nr = (struct netrange *) (sat2->sat_zero);
    150 		if ((nr->nr_phase == 2)
    151 		    && (nr->nr_firstnet <= sat->sat_addr.s_net)
    152 		    && (nr->nr_lastnet >= sat->sat_addr.s_net))
    153 			break;
    154 	}
    155 	return ifa;
    156 }
    157 
    158 static void
    159 aarpwhohas(ifp, sat)
    160 	struct ifnet *ifp;
    161 	struct sockaddr_at *sat;
    162 {
    163 	struct mbuf    *m;
    164 	struct ether_header *eh;
    165 	struct ether_aarp *ea;
    166 	struct at_ifaddr *aa;
    167 	struct llc     *llc;
    168 	struct sockaddr sa;
    169 
    170 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    171 		return;
    172 
    173 	MCLAIM(m, &aarp_mowner);
    174 	m->m_len = sizeof(*ea);
    175 	m->m_pkthdr.len = sizeof(*ea);
    176 	MH_ALIGN(m, sizeof(*ea));
    177 
    178 	ea = mtod(m, struct ether_aarp *);
    179 	bzero(ea, sizeof(*ea));
    180 
    181 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    182 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    183 	ea->aarp_hln = sizeof(ea->aarp_sha);
    184 	ea->aarp_pln = sizeof(ea->aarp_spu);
    185 	ea->aarp_op = htons(AARPOP_REQUEST);
    186 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    187 
    188 	/*
    189          * We need to check whether the output ethernet type should
    190          * be phase 1 or 2. We have the interface that we'll be sending
    191          * the aarp out. We need to find an AppleTalk network on that
    192          * interface with the same address as we're looking for. If the
    193          * net is phase 2, generate an 802.2 and SNAP header.
    194          */
    195 	if ((aa = (struct at_ifaddr *) at_ifawithnet(sat, ifp)) == NULL) {
    196 		m_freem(m);
    197 		return;
    198 	}
    199 	eh = (struct ether_header *) sa.sa_data;
    200 
    201 	if (aa->aa_flags & AFA_PHASE2) {
    202 		bcopy(atmulticastaddr, eh->ether_dhost,
    203 		    sizeof(eh->ether_dhost));
    204 		eh->ether_type = 0;	/* if_output will treat as 802 */
    205 		M_PREPEND(m, sizeof(struct llc), M_WAIT);
    206 		llc = mtod(m, struct llc *);
    207 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    208 		llc->llc_control = LLC_UI;
    209 		bcopy(aarp_org_code, llc->llc_org_code, sizeof(aarp_org_code));
    210 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    211 
    212 		bcopy(&AA_SAT(aa)->sat_addr.s_net, ea->aarp_spnet,
    213 		      sizeof(ea->aarp_spnet));
    214 		bcopy(&sat->sat_addr.s_net, ea->aarp_tpnet,
    215 		      sizeof(ea->aarp_tpnet));
    216 		ea->aarp_spnode = AA_SAT(aa)->sat_addr.s_node;
    217 		ea->aarp_tpnode = sat->sat_addr.s_node;
    218 	} else {
    219 		bcopy(etherbroadcastaddr, eh->ether_dhost,
    220 		    sizeof(eh->ether_dhost));
    221 		eh->ether_type = htons(ETHERTYPE_AARP);
    222 
    223 		ea->aarp_spa = AA_SAT(aa)->sat_addr.s_node;
    224 		ea->aarp_tpa = sat->sat_addr.s_node;
    225 	}
    226 
    227 #ifdef NETATALKDEBUG
    228 	printf("aarp: sending request via %u.%u seaking %u.%u\n",
    229 	    ntohs(AA_SAT(aa)->sat_addr.s_net), AA_SAT(aa)->sat_addr.s_node,
    230 	    ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
    231 #endif	/* NETATALKDEBUG */
    232 
    233 	sa.sa_len = sizeof(struct sockaddr);
    234 	sa.sa_family = AF_UNSPEC;
    235 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX NULL should be routing */
    236 						/* information */
    237 }
    238 
    239 int
    240 aarpresolve(ifp, m, destsat, desten)
    241 	struct ifnet   *ifp;
    242 	struct mbuf    *m;
    243 	struct sockaddr_at *destsat;
    244 	u_char         *desten;
    245 {
    246 	struct at_ifaddr *aa;
    247 	struct aarptab *aat;
    248 	int             s;
    249 
    250 	if (at_broadcast(destsat)) {
    251 		aa = (struct at_ifaddr *) at_ifawithnet(destsat, ifp);
    252 		if (aa == NULL) {
    253 			m_freem(m);
    254 			return (0);
    255 		}
    256 		if (aa->aa_flags & AFA_PHASE2)
    257 			bcopy(atmulticastaddr, desten,
    258 			    sizeof(atmulticastaddr));
    259 		else
    260 			bcopy(etherbroadcastaddr, desten,
    261 			    sizeof(etherbroadcastaddr));
    262 		return 1;
    263 	}
    264 	s = splnet();
    265 	AARPTAB_LOOK(aat, destsat->sat_addr);
    266 	if (aat == 0) {		/* No entry */
    267 		aat = aarptnew(&destsat->sat_addr);
    268 		if (aat == 0)
    269 			panic("aarpresolve: no free entry");
    270 
    271 		aat->aat_hold = m;
    272 		aarpwhohas(ifp, destsat);
    273 		splx(s);
    274 		return 0;
    275 	}
    276 
    277 	/* found an entry */
    278 	aat->aat_timer = 0;
    279 	if (aat->aat_flags & ATF_COM) {	/* entry is COMplete */
    280 		bcopy(aat->aat_enaddr, desten, sizeof(aat->aat_enaddr));
    281 		splx(s);
    282 		return 1;
    283 	}
    284 
    285 	/* entry has not completed */
    286 	if (aat->aat_hold)
    287 		m_freem(aat->aat_hold);
    288 	aat->aat_hold = m;
    289 	aarpwhohas(ifp, destsat);
    290 	splx(s);
    291 
    292 	return 0;
    293 }
    294 
    295 void
    296 aarpinput(ifp, m)
    297 	struct ifnet   *ifp;
    298 	struct mbuf    *m;
    299 {
    300 	struct arphdr  *ar;
    301 
    302 	if (ifp->if_flags & IFF_NOARP)
    303 		goto out;
    304 
    305 	if (m->m_len < sizeof(struct arphdr))
    306 		goto out;
    307 
    308 	ar = mtod(m, struct arphdr *);
    309 	if (ntohs(ar->ar_hrd) != AARPHRD_ETHER)
    310 		goto out;
    311 
    312 	if (m->m_len < sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
    313 		goto out;
    314 
    315 	switch (ntohs(ar->ar_pro)) {
    316 	case ETHERTYPE_ATALK:
    317 		at_aarpinput(ifp, m);
    318 		return;
    319 
    320 	default:
    321 		break;
    322 	}
    323 
    324 out:
    325 	m_freem(m);
    326 }
    327 
    328 static void
    329 at_aarpinput(ifp, m)
    330 	struct ifnet *ifp;
    331 	struct mbuf *m;
    332 {
    333 	struct ether_aarp *ea;
    334 	struct at_ifaddr *aa;
    335 	struct aarptab *aat;
    336 	struct ether_header *eh;
    337 	struct llc     *llc;
    338 	struct sockaddr_at sat;
    339 	struct sockaddr sa;
    340 	struct at_addr  spa, tpa, ma;
    341 	int             op;
    342 	u_int16_t       net;
    343 
    344 	ea = mtod(m, struct ether_aarp *);
    345 
    346 	/* Check to see if from my hardware address */
    347 	if (!bcmp(ea->aarp_sha, LLADDR(ifp->if_sadl), sizeof(ea->aarp_sha))) {
    348 		m_freem(m);
    349 		return;
    350 	}
    351 	op = ntohs(ea->aarp_op);
    352 	bcopy(ea->aarp_tpnet, &net, sizeof(net));
    353 
    354 	if (net != 0) {		/* should be ATADDR_ANYNET? */
    355 		sat.sat_len = sizeof(struct sockaddr_at);
    356 		sat.sat_family = AF_APPLETALK;
    357 		sat.sat_addr.s_net = net;
    358 		aa = (struct at_ifaddr *) at_ifawithnet(&sat, ifp);
    359 		if (aa == NULL) {
    360 			m_freem(m);
    361 			return;
    362 		}
    363 		bcopy(ea->aarp_spnet, &spa.s_net, sizeof(spa.s_net));
    364 		bcopy(ea->aarp_tpnet, &tpa.s_net, sizeof(tpa.s_net));
    365 	} else {
    366 		/*
    367 		 * Since we don't know the net, we just look for the first
    368 		 * phase 1 address on the interface.
    369 		 */
    370 		for (aa = (struct at_ifaddr *) ifp->if_addrlist.tqh_first; aa;
    371 		    aa = (struct at_ifaddr *) aa->aa_ifa.ifa_list.tqe_next) {
    372 			if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    373 			    (aa->aa_flags & AFA_PHASE2) == 0)
    374 				break;
    375 		}
    376 		if (aa == NULL) {
    377 			m_freem(m);
    378 			return;
    379 		}
    380 		tpa.s_net = spa.s_net = AA_SAT(aa)->sat_addr.s_net;
    381 	}
    382 
    383 	spa.s_node = ea->aarp_spnode;
    384 	tpa.s_node = ea->aarp_tpnode;
    385 	ma.s_net = AA_SAT(aa)->sat_addr.s_net;
    386 	ma.s_node = AA_SAT(aa)->sat_addr.s_node;
    387 
    388 	/*
    389          * This looks like it's from us.
    390          */
    391 	if (spa.s_net == ma.s_net && spa.s_node == ma.s_node) {
    392 		if (aa->aa_flags & AFA_PROBING) {
    393 			/*
    394 		         * We're probing, someone either responded to our
    395 			 * probe, or probed for the same address we'd like
    396 			 * to use. Change the address we're probing for.
    397 		         */
    398 			callout_stop(&aa->aa_probe_ch);
    399 			wakeup(aa);
    400 			m_freem(m);
    401 			return;
    402 		} else if (op != AARPOP_PROBE) {
    403 			/*
    404 		         * This is not a probe, and we're not probing.
    405 			 * This means that someone's saying they have the same
    406 			 * source address as the one we're using. Get upset...
    407 		         */
    408 			log(LOG_ERR, "aarp: duplicate AT address!! %s\n",
    409 			    ether_sprintf(ea->aarp_sha));
    410 			m_freem(m);
    411 			return;
    412 		}
    413 	}
    414 	AARPTAB_LOOK(aat, spa);
    415 	if (aat) {
    416 		if (op == AARPOP_PROBE) {
    417 			/*
    418 		         * Someone's probing for spa, deallocate the one we've
    419 			 * got, so that if the prober keeps the address, we'll
    420 			 * be able to arp for him.
    421 		         */
    422 			aarptfree(aat);
    423 			m_freem(m);
    424 			return;
    425 		}
    426 		bcopy(ea->aarp_sha, aat->aat_enaddr, sizeof(ea->aarp_sha));
    427 		aat->aat_flags |= ATF_COM;
    428 		if (aat->aat_hold) {
    429 			sat.sat_len = sizeof(struct sockaddr_at);
    430 			sat.sat_family = AF_APPLETALK;
    431 			sat.sat_addr = spa;
    432 			(*ifp->if_output)(ifp, aat->aat_hold,
    433 			    (struct sockaddr *) & sat, NULL);	/* XXX */
    434 			aat->aat_hold = 0;
    435 		}
    436 	}
    437 	if (aat == 0 && tpa.s_net == ma.s_net && tpa.s_node == ma.s_node
    438 	    && op != AARPOP_PROBE) {
    439 		if ((aat = aarptnew(&spa)) != NULL) {
    440 			bcopy(ea->aarp_sha, aat->aat_enaddr,
    441 			    sizeof(ea->aarp_sha));
    442 			aat->aat_flags |= ATF_COM;
    443 		}
    444 	}
    445 	/*
    446          * Don't respond to responses, and never respond if we're
    447          * still probing.
    448          */
    449 	if (tpa.s_net != ma.s_net || tpa.s_node != ma.s_node ||
    450 	    op == AARPOP_RESPONSE || (aa->aa_flags & AFA_PROBING)) {
    451 		m_freem(m);
    452 		return;
    453 	}
    454 	bcopy(ea->aarp_sha, ea->aarp_tha, sizeof(ea->aarp_sha));
    455 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    456 
    457 	/* XXX */
    458 	eh = (struct ether_header *) sa.sa_data;
    459 	bcopy(ea->aarp_tha, eh->ether_dhost, sizeof(eh->ether_dhost));
    460 
    461 	if (aa->aa_flags & AFA_PHASE2) {
    462 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    463 		if (m == NULL)
    464 			return;
    465 
    466 		llc = mtod(m, struct llc *);
    467 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    468 		llc->llc_control = LLC_UI;
    469 		bcopy(aarp_org_code, llc->llc_org_code, sizeof(aarp_org_code));
    470 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    471 
    472 		bcopy(ea->aarp_spnet, ea->aarp_tpnet, sizeof(ea->aarp_tpnet));
    473 		bcopy(&ma.s_net, ea->aarp_spnet, sizeof(ea->aarp_spnet));
    474 		eh->ether_type = 0;	/* if_output will treat as 802 */
    475 	} else {
    476 		eh->ether_type = htons(ETHERTYPE_AARP);
    477 	}
    478 
    479 	ea->aarp_tpnode = ea->aarp_spnode;
    480 	ea->aarp_spnode = ma.s_node;
    481 	ea->aarp_op = htons(AARPOP_RESPONSE);
    482 
    483 	sa.sa_len = sizeof(struct sockaddr);
    484 	sa.sa_family = AF_UNSPEC;
    485 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    486 	return;
    487 }
    488 
    489 static void
    490 aarptfree(aat)
    491 	struct aarptab *aat;
    492 {
    493 
    494 	if (aat->aat_hold)
    495 		m_freem(aat->aat_hold);
    496 	aat->aat_hold = 0;
    497 	aat->aat_timer = aat->aat_flags = 0;
    498 	aat->aat_ataddr.s_net = 0;
    499 	aat->aat_ataddr.s_node = 0;
    500 }
    501 
    502 static struct aarptab *
    503 aarptnew(addr)
    504 	struct at_addr *addr;
    505 {
    506 	int             n;
    507 	int             oldest = -1;
    508 	struct aarptab *aat, *aato = NULL;
    509 	static int      first = 1;
    510 
    511 	if (first) {
    512 		first = 0;
    513 		callout_init(&aarptimer_callout);
    514 		callout_reset(&aarptimer_callout, hz, aarptimer, NULL);
    515 		MOWNER_ATTACH(&aarp_mowner);
    516 	}
    517 	aat = &aarptab[AARPTAB_HASH(*addr) * AARPTAB_BSIZ];
    518 	for (n = 0; n < AARPTAB_BSIZ; n++, aat++) {
    519 		if (aat->aat_flags == 0)
    520 			goto out;
    521 		if (aat->aat_flags & ATF_PERM)
    522 			continue;
    523 		if ((int) aat->aat_timer > oldest) {
    524 			oldest = aat->aat_timer;
    525 			aato = aat;
    526 		}
    527 	}
    528 	if (aato == NULL)
    529 		return (NULL);
    530 	aat = aato;
    531 	aarptfree(aat);
    532 out:
    533 	aat->aat_ataddr = *addr;
    534 	aat->aat_flags = ATF_INUSE;
    535 	return (aat);
    536 }
    537 
    538 
    539 void
    540 aarpprobe(arp)
    541 	void *arp;
    542 {
    543 	struct mbuf    *m;
    544 	struct ether_header *eh;
    545 	struct ether_aarp *ea;
    546 	struct at_ifaddr *aa;
    547 	struct llc     *llc;
    548 	struct sockaddr sa;
    549 	struct ifnet   *ifp = arp;
    550 
    551 	/*
    552          * We need to check whether the output ethernet type should
    553          * be phase 1 or 2. We have the interface that we'll be sending
    554          * the aarp out. We need to find an AppleTalk network on that
    555          * interface with the same address as we're looking for. If the
    556          * net is phase 2, generate an 802.2 and SNAP header.
    557          */
    558 	for (aa = (struct at_ifaddr *) ifp->if_addrlist.tqh_first; aa;
    559 	     aa = (struct at_ifaddr *) aa->aa_ifa.ifa_list.tqe_next) {
    560 		if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    561 		    (aa->aa_flags & AFA_PROBING))
    562 			break;
    563 	}
    564 	if (aa == NULL) {	/* serious error XXX */
    565 		printf("aarpprobe why did this happen?!\n");
    566 		return;
    567 	}
    568 	if (aa->aa_probcnt <= 0) {
    569 		aa->aa_flags &= ~AFA_PROBING;
    570 		wakeup(aa);
    571 		return;
    572 	} else {
    573 		callout_reset(&aa->aa_probe_ch, hz / 5, aarpprobe, arp);
    574 	}
    575 
    576 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    577 		return;
    578 
    579 	MCLAIM(m, &aarp_mowner);
    580 	m->m_len = sizeof(*ea);
    581 	m->m_pkthdr.len = sizeof(*ea);
    582 	MH_ALIGN(m, sizeof(*ea));
    583 
    584 	ea = mtod(m, struct ether_aarp *);
    585 	bzero(ea, sizeof(*ea));
    586 
    587 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    588 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    589 	ea->aarp_hln = sizeof(ea->aarp_sha);
    590 	ea->aarp_pln = sizeof(ea->aarp_spu);
    591 	ea->aarp_op = htons(AARPOP_PROBE);
    592 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    593 
    594 	eh = (struct ether_header *) sa.sa_data;
    595 
    596 	if (aa->aa_flags & AFA_PHASE2) {
    597 		bcopy(atmulticastaddr, eh->ether_dhost,
    598 		    sizeof(eh->ether_dhost));
    599 		eh->ether_type = 0;	/* if_output will treat as 802 */
    600 		M_PREPEND(m, sizeof(struct llc), M_WAIT);
    601 		llc = mtod(m, struct llc *);
    602 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    603 		llc->llc_control = LLC_UI;
    604 		bcopy(aarp_org_code, llc->llc_org_code, sizeof(aarp_org_code));
    605 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    606 
    607 		bcopy(&AA_SAT(aa)->sat_addr.s_net, ea->aarp_spnet,
    608 		      sizeof(ea->aarp_spnet));
    609 		bcopy(&AA_SAT(aa)->sat_addr.s_net, ea->aarp_tpnet,
    610 		      sizeof(ea->aarp_tpnet));
    611 		ea->aarp_spnode = ea->aarp_tpnode =
    612 		    AA_SAT(aa)->sat_addr.s_node;
    613 	} else {
    614 		bcopy(etherbroadcastaddr, eh->ether_dhost,
    615 		    sizeof(eh->ether_dhost));
    616 		eh->ether_type = htons(ETHERTYPE_AARP);
    617 		ea->aarp_spa = ea->aarp_tpa = AA_SAT(aa)->sat_addr.s_node;
    618 	}
    619 
    620 #ifdef NETATALKDEBUG
    621 	printf("aarp: sending probe for %u.%u\n",
    622 	       ntohs(AA_SAT(aa)->sat_addr.s_net),
    623 	       AA_SAT(aa)->sat_addr.s_node);
    624 #endif	/* NETATALKDEBUG */
    625 
    626 	sa.sa_len = sizeof(struct sockaddr);
    627 	sa.sa_family = AF_UNSPEC;
    628 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    629 	aa->aa_probcnt--;
    630 }
    631 
    632 void
    633 aarp_clean()
    634 {
    635 	struct aarptab *aat;
    636 	int             i;
    637 
    638 	callout_stop(&aarptimer_callout);
    639 	for (i = 0, aat = aarptab; i < AARPTAB_SIZE; i++, aat++)
    640 		if (aat->aat_hold)
    641 			m_freem(aat->aat_hold);
    642 }
    643