xref: /netbsd-src/sys/netatalk/aarp.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*	$NetBSD: aarp.c,v 1.43 2018/12/22 14:28:56 maxv 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@umich.edu
27  */
28 
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: aarp.c,v 1.43 2018/12/22 14:28:56 maxv Exp $");
31 
32 #include "opt_mbuftrace.h"
33 #include "opt_atalk.h"
34 
35 #include <sys/param.h>
36 #include <sys/socket.h>
37 #include <sys/syslog.h>
38 #include <sys/systm.h>
39 #include <sys/callout.h>
40 #include <sys/proc.h>
41 #include <sys/mbuf.h>
42 #include <sys/time.h>
43 #include <sys/kernel.h>
44 #include <sys/socketvar.h>
45 #include <net/if.h>
46 #include <net/route.h>
47 #include <net/if_ether.h>
48 #include <net/if_dl.h>
49 #include <netinet/in.h>
50 #undef s_net
51 
52 #include <netatalk/at.h>
53 #include <netatalk/at_var.h>
54 #include <netatalk/aarp.h>
55 #include <netatalk/ddp_var.h>
56 #include <netatalk/phase2.h>
57 #include <netatalk/at_extern.h>
58 
59 static struct aarptab *aarptnew(const struct at_addr *);
60 static void aarptfree(struct aarptab *);
61 static void at_aarpinput(struct ifnet *, struct mbuf *);
62 static void aarptimer(void *);
63 static void aarpwhohas(struct ifnet *, const struct sockaddr_at *);
64 
65 #define AARPTAB_BSIZ	9
66 #define AARPTAB_NB	19
67 #define AARPTAB_SIZE	(AARPTAB_BSIZ * AARPTAB_NB)
68 struct aarptab  aarptab[AARPTAB_SIZE];
69 
70 #define AARPTAB_HASH(a) \
71     ((((a).s_net << 8 ) + (a).s_node ) % AARPTAB_NB )
72 
73 #define AARPTAB_LOOK(aat,addr) { \
74     int		n; \
75     aat = &aarptab[ AARPTAB_HASH(addr) * AARPTAB_BSIZ ]; \
76     for ( n = 0; n < AARPTAB_BSIZ; n++, aat++ ) \
77 	if ( aat->aat_ataddr.s_net == (addr).s_net && \
78 	     aat->aat_ataddr.s_node == (addr).s_node ) \
79 	    break; \
80 	if ( n >= AARPTAB_BSIZ ) \
81 	    aat = 0; \
82 }
83 
84 #define AARPT_AGE	(60 * 1)
85 #define AARPT_KILLC	20
86 #define AARPT_KILLI	3
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 = MOWNER_INIT("atalk", "arp");
102 #endif
103 
104 /*ARGSUSED*/
105 static void
106 aarptimer(void *ignored)
107 {
108 	struct aarptab *aat;
109 	int             i, s;
110 
111 	mutex_enter(softnet_lock);
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 	mutex_exit(softnet_lock);
126 }
127 
128 /*
129  * search through the network addresses to find one that includes the given
130  * network.. remember to take netranges into consideration.
131  */
132 struct ifaddr *
133 at_ifawithnet(const struct sockaddr_at *sat, struct ifnet *ifp)
134 {
135 	struct ifaddr *ifa;
136 	struct sockaddr_at *sat2;
137 	struct netrange *nr;
138 
139 	IFADDR_READER_FOREACH(ifa, ifp) {
140 		if (ifa->ifa_addr->sa_family != AF_APPLETALK)
141 			continue;
142 
143 		sat2 = satosat(ifa->ifa_addr);
144 		if (sat2->sat_addr.s_net == sat->sat_addr.s_net)
145 			break;
146 
147 		nr = (struct netrange *) (sat2->sat_zero);
148 		if ((nr->nr_phase == 2)
149 		    && (ntohs(nr->nr_firstnet) <= ntohs(sat->sat_addr.s_net))
150 		    && (ntohs(nr->nr_lastnet) >= ntohs(sat->sat_addr.s_net)))
151 			break;
152 	}
153 
154 	return ifa;
155 }
156 
157 static void
158 aarpwhohas(struct ifnet *ifp, 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 	m_align(m, sizeof(*ea));
174 
175 	ea = mtod(m, struct ether_aarp *);
176 	memset(ea, 0, 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 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), 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 		memcpy(eh->ether_dhost, atmulticastaddr,
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 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
210 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
211 
212 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
213 		      sizeof(ea->aarp_spnet));
214 		memcpy(ea->aarp_tpnet, &sat->sat_addr.s_net,
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 		memcpy(eh->ether_dhost, etherbroadcastaddr,
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 	/* If we are talking to ourselves, use the loopback interface. */
228 	if (AA_SAT(aa)->sat_addr.s_net == sat->sat_addr.s_net &&
229 	    AA_SAT(aa)->sat_addr.s_node == sat->sat_addr.s_node)
230 		ifp = lo0ifp;
231 
232 #ifdef NETATALKDEBUG
233 	printf("aarp: sending request via %u.%u through %s seeking %u.%u\n",
234 	    ntohs(AA_SAT(aa)->sat_addr.s_net),
235 	    AA_SAT(aa)->sat_addr.s_node,
236 	    ifp->if_xname,
237 	    ntohs(sat->sat_addr.s_net),
238 	    sat->sat_addr.s_node);
239 #endif /* NETATALKDEBUG */
240 
241 	sa.sa_len = sizeof(struct sockaddr);
242 	sa.sa_family = AF_UNSPEC;
243 	if_output_lock(ifp, ifp, m, &sa, NULL);	/* XXX NULL should be routing */
244 						/* information */
245 }
246 
247 int
248 aarpresolve(struct ifnet *ifp, struct mbuf *m,
249     const struct sockaddr_at *destsat, u_char *desten)
250 {
251 	struct at_ifaddr *aa;
252 	struct aarptab *aat;
253 	int             s;
254 
255 	if (at_broadcast(destsat)) {
256 		struct ifaddr *ifa;
257 
258 		s = pserialize_read_enter();
259 		ifa = at_ifawithnet(destsat, ifp);
260 		if (ifa == NULL) {
261 			pserialize_read_exit(s);
262 			m_freem(m);
263 			return (0);
264 		}
265 		aa = (struct at_ifaddr *)ifa;
266 
267 		if (aa->aa_flags & AFA_PHASE2)
268 			memcpy(desten, atmulticastaddr,
269 			    sizeof(atmulticastaddr));
270 		else
271 			memcpy(desten, etherbroadcastaddr,
272 			    sizeof(etherbroadcastaddr));
273 		pserialize_read_exit(s);
274 		return 1;
275 	}
276 	s = splnet();
277 	AARPTAB_LOOK(aat, destsat->sat_addr);
278 	if (aat == 0) {		/* No entry */
279 		aat = aarptnew(&destsat->sat_addr);
280 		if (aat == 0)
281 			panic("aarpresolve: no free entry");
282 
283 		aat->aat_hold = m;
284 		aarpwhohas(ifp, destsat);
285 		splx(s);
286 		return 0;
287 	}
288 
289 	/* found an entry */
290 	aat->aat_timer = 0;
291 	if (aat->aat_flags & ATF_COM) {	/* entry is COMplete */
292 		memcpy(desten, aat->aat_enaddr, sizeof(aat->aat_enaddr));
293 		splx(s);
294 		return 1;
295 	}
296 
297 	/* entry has not completed */
298 	if (aat->aat_hold)
299 		m_freem(aat->aat_hold);
300 	aat->aat_hold = m;
301 	aarpwhohas(ifp, destsat);
302 	splx(s);
303 
304 	return 0;
305 }
306 
307 void
308 aarpinput(struct ifnet *ifp, struct mbuf *m)
309 {
310 	struct arphdr  *ar;
311 
312 	if (ifp->if_flags & IFF_NOARP)
313 		goto out;
314 
315 	if (m->m_len < sizeof(struct arphdr))
316 		goto out;
317 
318 	ar = mtod(m, struct arphdr *);
319 	if (ntohs(ar->ar_hrd) != AARPHRD_ETHER)
320 		goto out;
321 
322 	if (m->m_len < sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
323 		goto out;
324 
325 	switch (ntohs(ar->ar_pro)) {
326 	case ETHERTYPE_ATALK:
327 		at_aarpinput(ifp, m);
328 		return;
329 
330 	default:
331 		break;
332 	}
333 
334 out:
335 	m_freem(m);
336 }
337 
338 static void
339 at_aarpinput(struct ifnet *ifp, struct mbuf *m)
340 {
341 	struct ether_aarp *ea;
342 	struct at_ifaddr *aa;
343 	struct aarptab *aat;
344 	struct ether_header *eh;
345 	struct llc     *llc;
346 	struct sockaddr_at sat;
347 	struct sockaddr sa;
348 	struct at_addr  spa, tpa, ma;
349 	int             op;
350 	u_int16_t       net;
351 	int		s;
352 	struct psref	psref;
353 	struct ifaddr *ifa;
354 
355 	/* We should also check ar_hln and ar_pln. */
356 	if ((m = m_pullup(m, sizeof(struct ether_aarp))) == NULL) {
357 		return;
358 	}
359 
360 	ea = mtod(m, struct ether_aarp *);
361 
362 	/* Check to see if from my hardware address */
363 	if (!memcmp(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha))) {
364 		m_freem(m);
365 		return;
366 	}
367 	op = ntohs(ea->aarp_op);
368 	memcpy(&net, ea->aarp_tpnet, sizeof(net));
369 
370 	if (net != 0) {		/* should be ATADDR_ANYNET? */
371 		sat.sat_len = sizeof(struct sockaddr_at);
372 		sat.sat_family = AF_APPLETALK;
373 		sat.sat_addr.s_net = net;
374 
375 		s = pserialize_read_enter();
376 		ifa = at_ifawithnet(&sat, ifp);
377 		if (ifa == NULL) {
378 			pserialize_read_exit(s);
379 			m_freem(m);
380 			return;
381 		}
382 		ifa_acquire(ifa, &psref);
383 		pserialize_read_exit(s);
384 		aa = (struct at_ifaddr *)ifa;
385 
386 		memcpy(&spa.s_net, ea->aarp_spnet, sizeof(spa.s_net));
387 		memcpy(&tpa.s_net, ea->aarp_tpnet, sizeof(tpa.s_net));
388 	} else {
389 		/*
390 		 * Since we don't know the net, we just look for the first
391 		 * phase 1 address on the interface.
392 		 */
393 		s = pserialize_read_enter();
394 		IFADDR_READER_FOREACH(ifa, ifp) {
395 			aa = (struct at_ifaddr *)ifa;
396 			if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
397 			    (aa->aa_flags & AFA_PHASE2) == 0) {
398 				ifa_acquire(ifa, &psref);
399 				break;
400 			}
401 		}
402 		pserialize_read_exit(s);
403 
404 		if (ifa == NULL) {
405 			m_freem(m);
406 			return;
407 		}
408 		tpa.s_net = spa.s_net = AA_SAT(aa)->sat_addr.s_net;
409 	}
410 
411 	spa.s_node = ea->aarp_spnode;
412 	tpa.s_node = ea->aarp_tpnode;
413 	ma.s_net = AA_SAT(aa)->sat_addr.s_net;
414 	ma.s_node = AA_SAT(aa)->sat_addr.s_node;
415 
416 	/*
417          * This looks like it's from us.
418          */
419 	if (spa.s_net == ma.s_net && spa.s_node == ma.s_node) {
420 		if (aa->aa_flags & AFA_PROBING) {
421 			/*
422 		         * We're probing, someone either responded to our
423 			 * probe, or probed for the same address we'd like
424 			 * to use. Change the address we're probing for.
425 		         */
426 			callout_stop(&aa->aa_probe_ch);
427 			wakeup(aa);
428 			m_freem(m);
429 			goto out;
430 		} else if (op != AARPOP_PROBE) {
431 			/*
432 		         * This is not a probe, and we're not probing.
433 			 * This means that someone's saying they have the same
434 			 * source address as the one we're using. Get upset...
435 		         */
436 			log(LOG_ERR, "aarp: duplicate AT address!! %s\n",
437 			    ether_sprintf(ea->aarp_sha));
438 			m_freem(m);
439 			goto out;
440 		}
441 	}
442 	AARPTAB_LOOK(aat, spa);
443 	if (aat) {
444 		if (op == AARPOP_PROBE) {
445 			/*
446 		         * Someone's probing for spa, deallocate the one we've
447 			 * got, so that if the prober keeps the address, we'll
448 			 * be able to arp for him.
449 		         */
450 			aarptfree(aat);
451 			m_freem(m);
452 			goto out;
453 		}
454 		memcpy(aat->aat_enaddr, ea->aarp_sha, sizeof(ea->aarp_sha));
455 		aat->aat_flags |= ATF_COM;
456 		if (aat->aat_hold) {
457 			sat.sat_len = sizeof(struct sockaddr_at);
458 			sat.sat_family = AF_APPLETALK;
459 			sat.sat_addr = spa;
460 			if_output_lock(ifp, ifp, aat->aat_hold,
461 			    (struct sockaddr *) & sat, NULL);	/* XXX */
462 			aat->aat_hold = 0;
463 		}
464 	}
465 	if (aat == 0 && tpa.s_net == ma.s_net && tpa.s_node == ma.s_node
466 	    && op != AARPOP_PROBE) {
467 		if ((aat = aarptnew(&spa)) != NULL) {
468 			memcpy(aat->aat_enaddr, ea->aarp_sha,
469 			    sizeof(ea->aarp_sha));
470 			aat->aat_flags |= ATF_COM;
471 		}
472 	}
473 	/*
474          * Don't respond to responses, and never respond if we're
475          * still probing.
476          */
477 	if (tpa.s_net != ma.s_net || tpa.s_node != ma.s_node ||
478 	    op == AARPOP_RESPONSE || (aa->aa_flags & AFA_PROBING)) {
479 		m_freem(m);
480 		goto out;
481 	}
482 
483 	/*
484 	 * Prepare and send AARP-response.
485 	 */
486 	m->m_len = sizeof(*ea);
487 	m->m_pkthdr.len = sizeof(*ea);
488 	memcpy(ea->aarp_tha, ea->aarp_sha, sizeof(ea->aarp_sha));
489 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
490 
491 	/* XXX */
492 	eh = (struct ether_header *) sa.sa_data;
493 	memcpy(eh->ether_dhost, ea->aarp_tha, sizeof(eh->ether_dhost));
494 
495 	if (aa->aa_flags & AFA_PHASE2) {
496 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
497 		if (m == NULL)
498 			goto out;
499 
500 		llc = mtod(m, struct llc *);
501 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
502 		llc->llc_control = LLC_UI;
503 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
504 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
505 
506 		memcpy(ea->aarp_tpnet, ea->aarp_spnet, sizeof(ea->aarp_tpnet));
507 		memcpy(ea->aarp_spnet, &ma.s_net, sizeof(ea->aarp_spnet));
508 		eh->ether_type = 0;	/* if_output will treat as 802 */
509 	} else {
510 		eh->ether_type = htons(ETHERTYPE_AARP);
511 	}
512 
513 	ea->aarp_tpnode = ea->aarp_spnode;
514 	ea->aarp_spnode = ma.s_node;
515 	ea->aarp_op = htons(AARPOP_RESPONSE);
516 
517 	sa.sa_len = sizeof(struct sockaddr);
518 	sa.sa_family = AF_UNSPEC;
519 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
520 out:
521 	ifa_release(ifa, &psref);
522 	return;
523 }
524 
525 static void
526 aarptfree(struct aarptab *aat)
527 {
528 
529 	if (aat->aat_hold)
530 		m_freem(aat->aat_hold);
531 	aat->aat_hold = 0;
532 	aat->aat_timer = aat->aat_flags = 0;
533 	aat->aat_ataddr.s_net = 0;
534 	aat->aat_ataddr.s_node = 0;
535 }
536 
537 static struct aarptab *
538 aarptnew(const struct at_addr *addr)
539 {
540 	int             n;
541 	int             oldest = -1;
542 	struct aarptab *aat, *aato = NULL;
543 	static int      first = 1;
544 
545 	if (first) {
546 		first = 0;
547 		callout_init(&aarptimer_callout, 0);
548 		callout_reset(&aarptimer_callout, hz, aarptimer, NULL);
549 	}
550 	aat = &aarptab[AARPTAB_HASH(*addr) * AARPTAB_BSIZ];
551 	for (n = 0; n < AARPTAB_BSIZ; n++, aat++) {
552 		if (aat->aat_flags == 0)
553 			goto out;
554 		if (aat->aat_flags & ATF_PERM)
555 			continue;
556 		if ((int) aat->aat_timer > oldest) {
557 			oldest = aat->aat_timer;
558 			aato = aat;
559 		}
560 	}
561 	if (aato == NULL)
562 		return (NULL);
563 	aat = aato;
564 	aarptfree(aat);
565 out:
566 	aat->aat_ataddr = *addr;
567 	aat->aat_flags = ATF_INUSE;
568 	return (aat);
569 }
570 
571 
572 void
573 aarpprobe(void *arp)
574 {
575 	struct mbuf    *m;
576 	struct ether_header *eh;
577 	struct ether_aarp *ea;
578 	struct ifaddr *ia;
579 	struct at_ifaddr *aa;
580 	struct llc     *llc;
581 	struct sockaddr sa;
582 	struct ifnet   *ifp = arp;
583 
584 	mutex_enter(softnet_lock);
585 
586 	/*
587          * We need to check whether the output ethernet type should
588          * be phase 1 or 2. We have the interface that we'll be sending
589          * the aarp out. We need to find an AppleTalk network on that
590          * interface with the same address as we're looking for. If the
591          * net is phase 2, generate an 802.2 and SNAP header.
592          */
593 	IFADDR_READER_FOREACH(ia, ifp) {
594 		aa = (struct at_ifaddr *)ia;
595 		if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
596 		    (aa->aa_flags & AFA_PROBING))
597 			break;
598 	}
599 	if (ia == NULL) {	/* serious error XXX */
600 		printf("aarpprobe why did this happen?!\n");
601 		mutex_exit(softnet_lock);
602 		return;
603 	}
604 	if (aa->aa_probcnt <= 0) {
605 		aa->aa_flags &= ~AFA_PROBING;
606 		wakeup(aa);
607 		mutex_exit(softnet_lock);
608 		return;
609 	} else {
610 		callout_reset(&aa->aa_probe_ch, hz / 5, aarpprobe, arp);
611 	}
612 
613 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) {
614 		mutex_exit(softnet_lock);
615 		return;
616 	}
617 
618 	MCLAIM(m, &aarp_mowner);
619 	m->m_len = sizeof(*ea);
620 	m->m_pkthdr.len = sizeof(*ea);
621 	m_align(m, sizeof(*ea));
622 
623 	ea = mtod(m, struct ether_aarp *);
624 	memset(ea, 0, sizeof(*ea));
625 
626 	ea->aarp_hrd = htons(AARPHRD_ETHER);
627 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
628 	ea->aarp_hln = sizeof(ea->aarp_sha);
629 	ea->aarp_pln = sizeof(ea->aarp_spu);
630 	ea->aarp_op = htons(AARPOP_PROBE);
631 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
632 
633 	eh = (struct ether_header *) sa.sa_data;
634 
635 	if (aa->aa_flags & AFA_PHASE2) {
636 		memcpy(eh->ether_dhost, atmulticastaddr,
637 		    sizeof(eh->ether_dhost));
638 		eh->ether_type = 0;	/* if_output will treat as 802 */
639 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
640 		if (!m) {
641 			mutex_exit(softnet_lock);
642 			return;
643 		}
644 
645 		llc = mtod(m, struct llc *);
646 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
647 		llc->llc_control = LLC_UI;
648 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
649 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
650 
651 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
652 		      sizeof(ea->aarp_spnet));
653 		memcpy(ea->aarp_tpnet, &AA_SAT(aa)->sat_addr.s_net,
654 		      sizeof(ea->aarp_tpnet));
655 		ea->aarp_spnode = ea->aarp_tpnode =
656 		    AA_SAT(aa)->sat_addr.s_node;
657 	} else {
658 		memcpy(eh->ether_dhost, etherbroadcastaddr,
659 		    sizeof(eh->ether_dhost));
660 		eh->ether_type = htons(ETHERTYPE_AARP);
661 		ea->aarp_spa = ea->aarp_tpa = AA_SAT(aa)->sat_addr.s_node;
662 	}
663 
664 #ifdef NETATALKDEBUG
665 	printf("aarp: sending probe for %u.%u\n",
666 	       ntohs(AA_SAT(aa)->sat_addr.s_net),
667 	       AA_SAT(aa)->sat_addr.s_node);
668 #endif	/* NETATALKDEBUG */
669 
670 	sa.sa_len = sizeof(struct sockaddr);
671 	sa.sa_family = AF_UNSPEC;
672 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
673 	aa->aa_probcnt--;
674 	mutex_exit(softnet_lock);
675 }
676