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aarp.c revision 1.22
      1 /*	$NetBSD: aarp.c,v 1.22 2007/02/17 22:34:10 dyoung 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 1.22 2007/02/17 22:34:10 dyoung Exp $");
     31 
     32 #include "opt_mbuftrace.h"
     33 
     34 #include <sys/param.h>
     35 #include <sys/socket.h>
     36 #include <sys/syslog.h>
     37 #include <sys/systm.h>
     38 #include <sys/callout.h>
     39 #include <sys/proc.h>
     40 #include <sys/mbuf.h>
     41 #include <sys/time.h>
     42 #include <sys/kernel.h>
     43 #include <net/if.h>
     44 #include <net/route.h>
     45 #include <net/if_ether.h>
     46 #include <net/if_dl.h>
     47 #include <netinet/in.h>
     48 #undef s_net
     49 
     50 #include <netatalk/at.h>
     51 #include <netatalk/at_var.h>
     52 #include <netatalk/aarp.h>
     53 #include <netatalk/ddp_var.h>
     54 #include <netatalk/phase2.h>
     55 #include <netatalk/at_extern.h>
     56 
     57 static struct aarptab *aarptnew(const struct at_addr *);
     58 static void aarptfree(struct aarptab *);
     59 static void at_aarpinput(struct ifnet *, struct mbuf *);
     60 static void aarptimer(void *);
     61 static void aarpwhohas(struct ifnet *, const struct sockaddr_at *);
     62 
     63 #define AARPTAB_BSIZ	9
     64 #define AARPTAB_NB	19
     65 #define AARPTAB_SIZE	(AARPTAB_BSIZ * AARPTAB_NB)
     66 struct aarptab  aarptab[AARPTAB_SIZE];
     67 
     68 #define AARPTAB_HASH(a) \
     69     ((((a).s_net << 8 ) + (a).s_node ) % AARPTAB_NB )
     70 
     71 #define AARPTAB_LOOK(aat,addr) { \
     72     int		n; \
     73     aat = &aarptab[ AARPTAB_HASH(addr) * AARPTAB_BSIZ ]; \
     74     for ( n = 0; n < AARPTAB_BSIZ; n++, aat++ ) \
     75 	if ( aat->aat_ataddr.s_net == (addr).s_net && \
     76 	     aat->aat_ataddr.s_node == (addr).s_node ) \
     77 	    break; \
     78 	if ( n >= AARPTAB_BSIZ ) \
     79 	    aat = 0; \
     80 }
     81 
     82 #define AARPT_AGE	(60 * 1)
     83 #define AARPT_KILLC	20
     84 #define AARPT_KILLI	3
     85 
     86 const u_char atmulticastaddr[6] = {
     87 	0x09, 0x00, 0x07, 0xff, 0xff, 0xff
     88 };
     89 
     90 const u_char at_org_code[3] = {
     91 	0x08, 0x00, 0x07
     92 };
     93 const u_char aarp_org_code[3] = {
     94 	0x00, 0x00, 0x00
     95 };
     96 
     97 struct callout aarptimer_callout;
     98 #ifdef MBUFTRACE
     99 struct mowner aarp_mowner = MOWNER_INIT("atalk", "arp");
    100 #endif
    101 
    102 /*ARGSUSED*/
    103 static void
    104 aarptimer(void *ignored)
    105 {
    106 	struct aarptab *aat;
    107 	int             i, s;
    108 
    109 	callout_reset(&aarptimer_callout, AARPT_AGE * hz, aarptimer, NULL);
    110 	aat = aarptab;
    111 	for (i = 0; i < AARPTAB_SIZE; i++, aat++) {
    112 		int killtime = (aat->aat_flags & ATF_COM) ? AARPT_KILLC :
    113 		    AARPT_KILLI;
    114 		if (aat->aat_flags == 0 || (aat->aat_flags & ATF_PERM))
    115 			continue;
    116 		if (++aat->aat_timer < killtime)
    117 			continue;
    118 		s = splnet();
    119 		aarptfree(aat);
    120 		splx(s);
    121 	}
    122 }
    123 
    124 /*
    125  * search through the network addresses to find one that includes the given
    126  * network.. remember to take netranges into consideration.
    127  */
    128 struct ifaddr *
    129 at_ifawithnet(sat, ifp)
    130 	const struct sockaddr_at *sat;
    131 	struct ifnet *ifp;
    132 {
    133 	struct ifaddr  *ifa;
    134 	struct sockaddr_at *sat2;
    135 	struct netrange *nr;
    136 
    137 	for (ifa = ifp->if_addrlist.tqh_first; ifa;
    138 	    ifa = ifa->ifa_list.tqe_next) {
    139 		if (ifa->ifa_addr->sa_family != AF_APPLETALK)
    140 			continue;
    141 
    142 		sat2 = satosat(ifa->ifa_addr);
    143 		if (sat2->sat_addr.s_net == sat->sat_addr.s_net)
    144 			break;
    145 
    146 		nr = (struct netrange *) (sat2->sat_zero);
    147 		if ((nr->nr_phase == 2)
    148 		    && (ntohs(nr->nr_firstnet) <= ntohs(sat->sat_addr.s_net))
    149 		    && (ntohs(nr->nr_lastnet) >= ntohs(sat->sat_addr.s_net)))
    150 			break;
    151 	}
    152 	return ifa;
    153 }
    154 
    155 static void
    156 aarpwhohas(ifp, sat)
    157 	struct ifnet *ifp;
    158 	const struct sockaddr_at *sat;
    159 {
    160 	struct mbuf    *m;
    161 	struct ether_header *eh;
    162 	struct ether_aarp *ea;
    163 	struct at_ifaddr *aa;
    164 	struct llc     *llc;
    165 	struct sockaddr sa;
    166 
    167 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    168 		return;
    169 
    170 	MCLAIM(m, &aarp_mowner);
    171 	m->m_len = sizeof(*ea);
    172 	m->m_pkthdr.len = sizeof(*ea);
    173 	MH_ALIGN(m, sizeof(*ea));
    174 
    175 	ea = mtod(m, struct ether_aarp *);
    176 	bzero(ea, sizeof(*ea));
    177 
    178 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    179 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    180 	ea->aarp_hln = sizeof(ea->aarp_sha);
    181 	ea->aarp_pln = sizeof(ea->aarp_spu);
    182 	ea->aarp_op = htons(AARPOP_REQUEST);
    183 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    184 
    185 	/*
    186          * We need to check whether the output ethernet type should
    187          * be phase 1 or 2. We have the interface that we'll be sending
    188          * the aarp out. We need to find an AppleTalk network on that
    189          * interface with the same address as we're looking for. If the
    190          * net is phase 2, generate an 802.2 and SNAP header.
    191          */
    192 	if ((aa = (struct at_ifaddr *) at_ifawithnet(sat, ifp)) == NULL) {
    193 		m_freem(m);
    194 		return;
    195 	}
    196 	eh = (struct ether_header *) sa.sa_data;
    197 
    198 	if (aa->aa_flags & AFA_PHASE2) {
    199 		bcopy(atmulticastaddr, eh->ether_dhost,
    200 		    sizeof(eh->ether_dhost));
    201 		eh->ether_type = 0;	/* if_output will treat as 802 */
    202 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    203 		if (!m)
    204 			return;
    205 
    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(struct ifnet *ifp, struct mbuf *m,
    241     const struct sockaddr_at *destsat, u_char *desten)
    242 {
    243 	struct at_ifaddr *aa;
    244 	struct aarptab *aat;
    245 	int             s;
    246 
    247 	if (at_broadcast(destsat)) {
    248 		aa = (struct at_ifaddr *) at_ifawithnet(destsat, ifp);
    249 		if (aa == NULL) {
    250 			m_freem(m);
    251 			return (0);
    252 		}
    253 		if (aa->aa_flags & AFA_PHASE2)
    254 			bcopy(atmulticastaddr, desten,
    255 			    sizeof(atmulticastaddr));
    256 		else
    257 			bcopy(etherbroadcastaddr, desten,
    258 			    sizeof(etherbroadcastaddr));
    259 		return 1;
    260 	}
    261 	s = splnet();
    262 	AARPTAB_LOOK(aat, destsat->sat_addr);
    263 	if (aat == 0) {		/* No entry */
    264 		aat = aarptnew(&destsat->sat_addr);
    265 		if (aat == 0)
    266 			panic("aarpresolve: no free entry");
    267 
    268 		aat->aat_hold = m;
    269 		aarpwhohas(ifp, destsat);
    270 		splx(s);
    271 		return 0;
    272 	}
    273 
    274 	/* found an entry */
    275 	aat->aat_timer = 0;
    276 	if (aat->aat_flags & ATF_COM) {	/* entry is COMplete */
    277 		bcopy(aat->aat_enaddr, desten, sizeof(aat->aat_enaddr));
    278 		splx(s);
    279 		return 1;
    280 	}
    281 
    282 	/* entry has not completed */
    283 	if (aat->aat_hold)
    284 		m_freem(aat->aat_hold);
    285 	aat->aat_hold = m;
    286 	aarpwhohas(ifp, destsat);
    287 	splx(s);
    288 
    289 	return 0;
    290 }
    291 
    292 void
    293 aarpinput(ifp, m)
    294 	struct ifnet   *ifp;
    295 	struct mbuf    *m;
    296 {
    297 	struct arphdr  *ar;
    298 
    299 	if (ifp->if_flags & IFF_NOARP)
    300 		goto out;
    301 
    302 	if (m->m_len < sizeof(struct arphdr))
    303 		goto out;
    304 
    305 	ar = mtod(m, struct arphdr *);
    306 	if (ntohs(ar->ar_hrd) != AARPHRD_ETHER)
    307 		goto out;
    308 
    309 	if (m->m_len < sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
    310 		goto out;
    311 
    312 	switch (ntohs(ar->ar_pro)) {
    313 	case ETHERTYPE_ATALK:
    314 		at_aarpinput(ifp, m);
    315 		return;
    316 
    317 	default:
    318 		break;
    319 	}
    320 
    321 out:
    322 	m_freem(m);
    323 }
    324 
    325 static void
    326 at_aarpinput(ifp, m)
    327 	struct ifnet *ifp;
    328 	struct mbuf *m;
    329 {
    330 	struct ether_aarp *ea;
    331 	struct at_ifaddr *aa;
    332 	struct aarptab *aat;
    333 	struct ether_header *eh;
    334 	struct llc     *llc;
    335 	struct sockaddr_at sat;
    336 	struct sockaddr sa;
    337 	struct at_addr  spa, tpa, ma;
    338 	int             op;
    339 	u_int16_t       net;
    340 
    341 	ea = mtod(m, struct ether_aarp *);
    342 
    343 	/* Check to see if from my hardware address */
    344 	if (!bcmp(ea->aarp_sha, LLADDR(ifp->if_sadl), sizeof(ea->aarp_sha))) {
    345 		m_freem(m);
    346 		return;
    347 	}
    348 	op = ntohs(ea->aarp_op);
    349 	bcopy(ea->aarp_tpnet, &net, sizeof(net));
    350 
    351 	if (net != 0) {		/* should be ATADDR_ANYNET? */
    352 		sat.sat_len = sizeof(struct sockaddr_at);
    353 		sat.sat_family = AF_APPLETALK;
    354 		sat.sat_addr.s_net = net;
    355 		aa = (struct at_ifaddr *) at_ifawithnet(&sat, ifp);
    356 		if (aa == NULL) {
    357 			m_freem(m);
    358 			return;
    359 		}
    360 		bcopy(ea->aarp_spnet, &spa.s_net, sizeof(spa.s_net));
    361 		bcopy(ea->aarp_tpnet, &tpa.s_net, sizeof(tpa.s_net));
    362 	} else {
    363 		/*
    364 		 * Since we don't know the net, we just look for the first
    365 		 * phase 1 address on the interface.
    366 		 */
    367 		for (aa = (struct at_ifaddr *) ifp->if_addrlist.tqh_first; aa;
    368 		    aa = (struct at_ifaddr *) aa->aa_ifa.ifa_list.tqe_next) {
    369 			if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    370 			    (aa->aa_flags & AFA_PHASE2) == 0)
    371 				break;
    372 		}
    373 		if (aa == NULL) {
    374 			m_freem(m);
    375 			return;
    376 		}
    377 		tpa.s_net = spa.s_net = AA_SAT(aa)->sat_addr.s_net;
    378 	}
    379 
    380 	spa.s_node = ea->aarp_spnode;
    381 	tpa.s_node = ea->aarp_tpnode;
    382 	ma.s_net = AA_SAT(aa)->sat_addr.s_net;
    383 	ma.s_node = AA_SAT(aa)->sat_addr.s_node;
    384 
    385 	/*
    386          * This looks like it's from us.
    387          */
    388 	if (spa.s_net == ma.s_net && spa.s_node == ma.s_node) {
    389 		if (aa->aa_flags & AFA_PROBING) {
    390 			/*
    391 		         * We're probing, someone either responded to our
    392 			 * probe, or probed for the same address we'd like
    393 			 * to use. Change the address we're probing for.
    394 		         */
    395 			callout_stop(&aa->aa_probe_ch);
    396 			wakeup(aa);
    397 			m_freem(m);
    398 			return;
    399 		} else if (op != AARPOP_PROBE) {
    400 			/*
    401 		         * This is not a probe, and we're not probing.
    402 			 * This means that someone's saying they have the same
    403 			 * source address as the one we're using. Get upset...
    404 		         */
    405 			log(LOG_ERR, "aarp: duplicate AT address!! %s\n",
    406 			    ether_sprintf(ea->aarp_sha));
    407 			m_freem(m);
    408 			return;
    409 		}
    410 	}
    411 	AARPTAB_LOOK(aat, spa);
    412 	if (aat) {
    413 		if (op == AARPOP_PROBE) {
    414 			/*
    415 		         * Someone's probing for spa, deallocate the one we've
    416 			 * got, so that if the prober keeps the address, we'll
    417 			 * be able to arp for him.
    418 		         */
    419 			aarptfree(aat);
    420 			m_freem(m);
    421 			return;
    422 		}
    423 		bcopy(ea->aarp_sha, aat->aat_enaddr, sizeof(ea->aarp_sha));
    424 		aat->aat_flags |= ATF_COM;
    425 		if (aat->aat_hold) {
    426 			sat.sat_len = sizeof(struct sockaddr_at);
    427 			sat.sat_family = AF_APPLETALK;
    428 			sat.sat_addr = spa;
    429 			(*ifp->if_output)(ifp, aat->aat_hold,
    430 			    (struct sockaddr *) & sat, NULL);	/* XXX */
    431 			aat->aat_hold = 0;
    432 		}
    433 	}
    434 	if (aat == 0 && tpa.s_net == ma.s_net && tpa.s_node == ma.s_node
    435 	    && op != AARPOP_PROBE) {
    436 		if ((aat = aarptnew(&spa)) != NULL) {
    437 			bcopy(ea->aarp_sha, aat->aat_enaddr,
    438 			    sizeof(ea->aarp_sha));
    439 			aat->aat_flags |= ATF_COM;
    440 		}
    441 	}
    442 	/*
    443          * Don't respond to responses, and never respond if we're
    444          * still probing.
    445          */
    446 	if (tpa.s_net != ma.s_net || tpa.s_node != ma.s_node ||
    447 	    op == AARPOP_RESPONSE || (aa->aa_flags & AFA_PROBING)) {
    448 		m_freem(m);
    449 		return;
    450 	}
    451 	bcopy(ea->aarp_sha, ea->aarp_tha, sizeof(ea->aarp_sha));
    452 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    453 
    454 	/* XXX */
    455 	eh = (struct ether_header *) sa.sa_data;
    456 	bcopy(ea->aarp_tha, eh->ether_dhost, sizeof(eh->ether_dhost));
    457 
    458 	if (aa->aa_flags & AFA_PHASE2) {
    459 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    460 		if (m == NULL)
    461 			return;
    462 
    463 		llc = mtod(m, struct llc *);
    464 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    465 		llc->llc_control = LLC_UI;
    466 		bcopy(aarp_org_code, llc->llc_org_code, sizeof(aarp_org_code));
    467 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    468 
    469 		bcopy(ea->aarp_spnet, ea->aarp_tpnet, sizeof(ea->aarp_tpnet));
    470 		bcopy(&ma.s_net, ea->aarp_spnet, sizeof(ea->aarp_spnet));
    471 		eh->ether_type = 0;	/* if_output will treat as 802 */
    472 	} else {
    473 		eh->ether_type = htons(ETHERTYPE_AARP);
    474 	}
    475 
    476 	ea->aarp_tpnode = ea->aarp_spnode;
    477 	ea->aarp_spnode = ma.s_node;
    478 	ea->aarp_op = htons(AARPOP_RESPONSE);
    479 
    480 	sa.sa_len = sizeof(struct sockaddr);
    481 	sa.sa_family = AF_UNSPEC;
    482 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    483 	return;
    484 }
    485 
    486 static void
    487 aarptfree(aat)
    488 	struct aarptab *aat;
    489 {
    490 
    491 	if (aat->aat_hold)
    492 		m_freem(aat->aat_hold);
    493 	aat->aat_hold = 0;
    494 	aat->aat_timer = aat->aat_flags = 0;
    495 	aat->aat_ataddr.s_net = 0;
    496 	aat->aat_ataddr.s_node = 0;
    497 }
    498 
    499 static struct aarptab *
    500 aarptnew(const struct at_addr *addr)
    501 {
    502 	int             n;
    503 	int             oldest = -1;
    504 	struct aarptab *aat, *aato = NULL;
    505 	static int      first = 1;
    506 
    507 	if (first) {
    508 		first = 0;
    509 		callout_init(&aarptimer_callout);
    510 		callout_reset(&aarptimer_callout, hz, aarptimer, NULL);
    511 		MOWNER_ATTACH(&aarp_mowner);
    512 	}
    513 	aat = &aarptab[AARPTAB_HASH(*addr) * AARPTAB_BSIZ];
    514 	for (n = 0; n < AARPTAB_BSIZ; n++, aat++) {
    515 		if (aat->aat_flags == 0)
    516 			goto out;
    517 		if (aat->aat_flags & ATF_PERM)
    518 			continue;
    519 		if ((int) aat->aat_timer > oldest) {
    520 			oldest = aat->aat_timer;
    521 			aato = aat;
    522 		}
    523 	}
    524 	if (aato == NULL)
    525 		return (NULL);
    526 	aat = aato;
    527 	aarptfree(aat);
    528 out:
    529 	aat->aat_ataddr = *addr;
    530 	aat->aat_flags = ATF_INUSE;
    531 	return (aat);
    532 }
    533 
    534 
    535 void
    536 aarpprobe(arp)
    537 	void *arp;
    538 {
    539 	struct mbuf    *m;
    540 	struct ether_header *eh;
    541 	struct ether_aarp *ea;
    542 	struct at_ifaddr *aa;
    543 	struct llc     *llc;
    544 	struct sockaddr sa;
    545 	struct ifnet   *ifp = arp;
    546 
    547 	/*
    548          * We need to check whether the output ethernet type should
    549          * be phase 1 or 2. We have the interface that we'll be sending
    550          * the aarp out. We need to find an AppleTalk network on that
    551          * interface with the same address as we're looking for. If the
    552          * net is phase 2, generate an 802.2 and SNAP header.
    553          */
    554 	for (aa = (struct at_ifaddr *) ifp->if_addrlist.tqh_first; aa;
    555 	     aa = (struct at_ifaddr *) aa->aa_ifa.ifa_list.tqe_next) {
    556 		if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    557 		    (aa->aa_flags & AFA_PROBING))
    558 			break;
    559 	}
    560 	if (aa == NULL) {	/* serious error XXX */
    561 		printf("aarpprobe why did this happen?!\n");
    562 		return;
    563 	}
    564 	if (aa->aa_probcnt <= 0) {
    565 		aa->aa_flags &= ~AFA_PROBING;
    566 		wakeup(aa);
    567 		return;
    568 	} else {
    569 		callout_reset(&aa->aa_probe_ch, hz / 5, aarpprobe, arp);
    570 	}
    571 
    572 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    573 		return;
    574 
    575 	MCLAIM(m, &aarp_mowner);
    576 	m->m_len = sizeof(*ea);
    577 	m->m_pkthdr.len = sizeof(*ea);
    578 	MH_ALIGN(m, sizeof(*ea));
    579 
    580 	ea = mtod(m, struct ether_aarp *);
    581 	bzero(ea, sizeof(*ea));
    582 
    583 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    584 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    585 	ea->aarp_hln = sizeof(ea->aarp_sha);
    586 	ea->aarp_pln = sizeof(ea->aarp_spu);
    587 	ea->aarp_op = htons(AARPOP_PROBE);
    588 	bcopy(LLADDR(ifp->if_sadl), ea->aarp_sha, sizeof(ea->aarp_sha));
    589 
    590 	eh = (struct ether_header *) sa.sa_data;
    591 
    592 	if (aa->aa_flags & AFA_PHASE2) {
    593 		bcopy(atmulticastaddr, eh->ether_dhost,
    594 		    sizeof(eh->ether_dhost));
    595 		eh->ether_type = 0;	/* if_output will treat as 802 */
    596 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    597 		if (!m)
    598 			return;
    599 
    600 		llc = mtod(m, struct llc *);
    601 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    602 		llc->llc_control = LLC_UI;
    603 		bcopy(aarp_org_code, llc->llc_org_code, sizeof(aarp_org_code));
    604 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    605 
    606 		bcopy(&AA_SAT(aa)->sat_addr.s_net, ea->aarp_spnet,
    607 		      sizeof(ea->aarp_spnet));
    608 		bcopy(&AA_SAT(aa)->sat_addr.s_net, ea->aarp_tpnet,
    609 		      sizeof(ea->aarp_tpnet));
    610 		ea->aarp_spnode = ea->aarp_tpnode =
    611 		    AA_SAT(aa)->sat_addr.s_node;
    612 	} else {
    613 		bcopy(etherbroadcastaddr, eh->ether_dhost,
    614 		    sizeof(eh->ether_dhost));
    615 		eh->ether_type = htons(ETHERTYPE_AARP);
    616 		ea->aarp_spa = ea->aarp_tpa = AA_SAT(aa)->sat_addr.s_node;
    617 	}
    618 
    619 #ifdef NETATALKDEBUG
    620 	printf("aarp: sending probe for %u.%u\n",
    621 	       ntohs(AA_SAT(aa)->sat_addr.s_net),
    622 	       AA_SAT(aa)->sat_addr.s_node);
    623 #endif	/* NETATALKDEBUG */
    624 
    625 	sa.sa_len = sizeof(struct sockaddr);
    626 	sa.sa_family = AF_UNSPEC;
    627 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    628 	aa->aa_probcnt--;
    629 }
    630 
    631 void
    632 aarp_clean()
    633 {
    634 	struct aarptab *aat;
    635 	int             i;
    636 
    637 	callout_stop(&aarptimer_callout);
    638 	for (i = 0, aat = aarptab; i < AARPTAB_SIZE; i++, aat++)
    639 		if (aat->aat_hold)
    640 			m_freem(aat->aat_hold);
    641 }
    642