xref: /netbsd-src/sys/netatalk/aarp.c (revision 87d689fb734c654d2486f87f7be32f1b53ecdbec)
1 /*	$NetBSD: aarp.c,v 1.40 2017/12/09 10:14:04 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 1.40 2017/12/09 10:14:04 maxv 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 <sys/socketvar.h>
44 #include <net/if.h>
45 #include <net/route.h>
46 #include <net/if_ether.h>
47 #include <net/if_dl.h>
48 #include <netinet/in.h>
49 #undef s_net
50 
51 #include <netatalk/at.h>
52 #include <netatalk/at_var.h>
53 #include <netatalk/aarp.h>
54 #include <netatalk/ddp_var.h>
55 #include <netatalk/phase2.h>
56 #include <netatalk/at_extern.h>
57 
58 static struct aarptab *aarptnew(const struct at_addr *);
59 static void aarptfree(struct aarptab *);
60 static void at_aarpinput(struct ifnet *, struct mbuf *);
61 static void aarptimer(void *);
62 static void aarpwhohas(struct ifnet *, const struct sockaddr_at *);
63 
64 #define AARPTAB_BSIZ	9
65 #define AARPTAB_NB	19
66 #define AARPTAB_SIZE	(AARPTAB_BSIZ * AARPTAB_NB)
67 struct aarptab  aarptab[AARPTAB_SIZE];
68 
69 #define AARPTAB_HASH(a) \
70     ((((a).s_net << 8 ) + (a).s_node ) % AARPTAB_NB )
71 
72 #define AARPTAB_LOOK(aat,addr) { \
73     int		n; \
74     aat = &aarptab[ AARPTAB_HASH(addr) * AARPTAB_BSIZ ]; \
75     for ( n = 0; n < AARPTAB_BSIZ; n++, aat++ ) \
76 	if ( aat->aat_ataddr.s_net == (addr).s_net && \
77 	     aat->aat_ataddr.s_node == (addr).s_node ) \
78 	    break; \
79 	if ( n >= AARPTAB_BSIZ ) \
80 	    aat = 0; \
81 }
82 
83 #define AARPT_AGE	(60 * 1)
84 #define AARPT_KILLC	20
85 #define AARPT_KILLI	3
86 
87 const u_char atmulticastaddr[6] = {
88 	0x09, 0x00, 0x07, 0xff, 0xff, 0xff
89 };
90 
91 const u_char at_org_code[3] = {
92 	0x08, 0x00, 0x07
93 };
94 const u_char aarp_org_code[3] = {
95 	0x00, 0x00, 0x00
96 };
97 
98 struct callout aarptimer_callout;
99 #ifdef MBUFTRACE
100 struct mowner aarp_mowner = MOWNER_INIT("atalk", "arp");
101 #endif
102 
103 /*ARGSUSED*/
104 static void
105 aarptimer(void *ignored)
106 {
107 	struct aarptab *aat;
108 	int             i, s;
109 
110 	mutex_enter(softnet_lock);
111 	callout_reset(&aarptimer_callout, AARPT_AGE * hz, aarptimer, NULL);
112 	aat = aarptab;
113 	for (i = 0; i < AARPTAB_SIZE; i++, aat++) {
114 		int killtime = (aat->aat_flags & ATF_COM) ? AARPT_KILLC :
115 		    AARPT_KILLI;
116 		if (aat->aat_flags == 0 || (aat->aat_flags & ATF_PERM))
117 			continue;
118 		if (++aat->aat_timer < killtime)
119 			continue;
120 		s = splnet();
121 		aarptfree(aat);
122 		splx(s);
123 	}
124 	mutex_exit(softnet_lock);
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(const struct sockaddr_at *sat, struct ifnet *ifp)
133 {
134 	struct ifaddr *ifa;
135 	struct sockaddr_at *sat2;
136 	struct netrange *nr;
137 
138 	IFADDR_READER_FOREACH(ifa, ifp) {
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 
153 	return ifa;
154 }
155 
156 static void
157 aarpwhohas(struct ifnet *ifp, const struct sockaddr_at *sat)
158 {
159 	struct mbuf    *m;
160 	struct ether_header *eh;
161 	struct ether_aarp *ea;
162 	struct at_ifaddr *aa;
163 	struct llc     *llc;
164 	struct sockaddr sa;
165 
166 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
167 		return;
168 
169 	MCLAIM(m, &aarp_mowner);
170 	m->m_len = sizeof(*ea);
171 	m->m_pkthdr.len = sizeof(*ea);
172 	MH_ALIGN(m, sizeof(*ea));
173 
174 	ea = mtod(m, struct ether_aarp *);
175 	memset(ea, 0, sizeof(*ea));
176 
177 	ea->aarp_hrd = htons(AARPHRD_ETHER);
178 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
179 	ea->aarp_hln = sizeof(ea->aarp_sha);
180 	ea->aarp_pln = sizeof(ea->aarp_spu);
181 	ea->aarp_op = htons(AARPOP_REQUEST);
182 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
183 
184 	/*
185          * We need to check whether the output ethernet type should
186          * be phase 1 or 2. We have the interface that we'll be sending
187          * the aarp out. We need to find an AppleTalk network on that
188          * interface with the same address as we're looking for. If the
189          * net is phase 2, generate an 802.2 and SNAP header.
190          */
191 	if ((aa = (struct at_ifaddr *) at_ifawithnet(sat, ifp)) == NULL) {
192 		m_freem(m);
193 		return;
194 	}
195 	eh = (struct ether_header *) sa.sa_data;
196 
197 	if (aa->aa_flags & AFA_PHASE2) {
198 		memcpy(eh->ether_dhost, atmulticastaddr,
199 		    sizeof(eh->ether_dhost));
200 		eh->ether_type = 0;	/* if_output will treat as 802 */
201 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
202 		if (!m)
203 			return;
204 
205 		llc = mtod(m, struct llc *);
206 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
207 		llc->llc_control = LLC_UI;
208 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
209 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
210 
211 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
212 		      sizeof(ea->aarp_spnet));
213 		memcpy(ea->aarp_tpnet, &sat->sat_addr.s_net,
214 		      sizeof(ea->aarp_tpnet));
215 		ea->aarp_spnode = AA_SAT(aa)->sat_addr.s_node;
216 		ea->aarp_tpnode = sat->sat_addr.s_node;
217 	} else {
218 		memcpy(eh->ether_dhost, etherbroadcastaddr,
219 		    sizeof(eh->ether_dhost));
220 		eh->ether_type = htons(ETHERTYPE_AARP);
221 
222 		ea->aarp_spa = AA_SAT(aa)->sat_addr.s_node;
223 		ea->aarp_tpa = sat->sat_addr.s_node;
224 	}
225 
226 	/* If we are talking to ourselves, use the loopback interface. */
227 	if (AA_SAT(aa)->sat_addr.s_net == sat->sat_addr.s_net &&
228 	    AA_SAT(aa)->sat_addr.s_node == sat->sat_addr.s_node)
229 		ifp = lo0ifp;
230 
231 #ifdef NETATALKDEBUG
232 	printf("aarp: sending request via %u.%u through %s seeking %u.%u\n",
233 	    ntohs(AA_SAT(aa)->sat_addr.s_net),
234 	    AA_SAT(aa)->sat_addr.s_node,
235 	    ifp->if_xname,
236 	    ntohs(sat->sat_addr.s_net),
237 	    sat->sat_addr.s_node);
238 #endif /* NETATALKDEBUG */
239 
240 	sa.sa_len = sizeof(struct sockaddr);
241 	sa.sa_family = AF_UNSPEC;
242 	if_output_lock(ifp, ifp, m, &sa, NULL);	/* XXX NULL should be routing */
243 						/* information */
244 }
245 
246 int
247 aarpresolve(struct ifnet *ifp, struct mbuf *m,
248     const struct sockaddr_at *destsat, u_char *desten)
249 {
250 	struct at_ifaddr *aa;
251 	struct aarptab *aat;
252 	int             s;
253 
254 	if (at_broadcast(destsat)) {
255 		struct ifaddr *ifa;
256 
257 		s = pserialize_read_enter();
258 		ifa = at_ifawithnet(destsat, ifp);
259 		if (ifa == NULL) {
260 			pserialize_read_exit(s);
261 			m_freem(m);
262 			return (0);
263 		}
264 		aa = (struct at_ifaddr *)ifa;
265 
266 		if (aa->aa_flags & AFA_PHASE2)
267 			memcpy(desten, atmulticastaddr,
268 			    sizeof(atmulticastaddr));
269 		else
270 			memcpy(desten, etherbroadcastaddr,
271 			    sizeof(etherbroadcastaddr));
272 		pserialize_read_exit(s);
273 		return 1;
274 	}
275 	s = splnet();
276 	AARPTAB_LOOK(aat, destsat->sat_addr);
277 	if (aat == 0) {		/* No entry */
278 		aat = aarptnew(&destsat->sat_addr);
279 		if (aat == 0)
280 			panic("aarpresolve: no free entry");
281 
282 		aat->aat_hold = m;
283 		aarpwhohas(ifp, destsat);
284 		splx(s);
285 		return 0;
286 	}
287 
288 	/* found an entry */
289 	aat->aat_timer = 0;
290 	if (aat->aat_flags & ATF_COM) {	/* entry is COMplete */
291 		memcpy(desten, aat->aat_enaddr, sizeof(aat->aat_enaddr));
292 		splx(s);
293 		return 1;
294 	}
295 
296 	/* entry has not completed */
297 	if (aat->aat_hold)
298 		m_freem(aat->aat_hold);
299 	aat->aat_hold = m;
300 	aarpwhohas(ifp, destsat);
301 	splx(s);
302 
303 	return 0;
304 }
305 
306 void
307 aarpinput(struct ifnet *ifp, struct mbuf *m)
308 {
309 	struct arphdr  *ar;
310 
311 	if (ifp->if_flags & IFF_NOARP)
312 		goto out;
313 
314 	if (m->m_len < sizeof(struct arphdr))
315 		goto out;
316 
317 	ar = mtod(m, struct arphdr *);
318 	if (ntohs(ar->ar_hrd) != AARPHRD_ETHER)
319 		goto out;
320 
321 	if (m->m_len < sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
322 		goto out;
323 
324 	switch (ntohs(ar->ar_pro)) {
325 	case ETHERTYPE_ATALK:
326 		at_aarpinput(ifp, m);
327 		return;
328 
329 	default:
330 		break;
331 	}
332 
333 out:
334 	m_freem(m);
335 }
336 
337 static void
338 at_aarpinput(struct ifnet *ifp, struct mbuf *m)
339 {
340 	struct ether_aarp *ea;
341 	struct at_ifaddr *aa;
342 	struct aarptab *aat;
343 	struct ether_header *eh;
344 	struct llc     *llc;
345 	struct sockaddr_at sat;
346 	struct sockaddr sa;
347 	struct at_addr  spa, tpa, ma;
348 	int             op;
349 	u_int16_t       net;
350 	int		s;
351 	struct psref	psref;
352 	struct ifaddr *ifa;
353 
354 	/* We should also check ar_hln and ar_pln. */
355 	if ((m = m_pullup(m, sizeof(struct ether_aarp))) == NULL) {
356 		return;
357 	}
358 
359 	ea = mtod(m, struct ether_aarp *);
360 
361 	/* Check to see if from my hardware address */
362 	if (!memcmp(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha))) {
363 		m_freem(m);
364 		return;
365 	}
366 	op = ntohs(ea->aarp_op);
367 	memcpy(&net, ea->aarp_tpnet, sizeof(net));
368 
369 	if (net != 0) {		/* should be ATADDR_ANYNET? */
370 		sat.sat_len = sizeof(struct sockaddr_at);
371 		sat.sat_family = AF_APPLETALK;
372 		sat.sat_addr.s_net = net;
373 
374 		s = pserialize_read_enter();
375 		ifa = at_ifawithnet(&sat, ifp);
376 		if (ifa == NULL) {
377 			pserialize_read_exit(s);
378 			m_freem(m);
379 			return;
380 		}
381 		ifa_acquire(ifa, &psref);
382 		pserialize_read_exit(s);
383 		aa = (struct at_ifaddr *)ifa;
384 
385 		memcpy(&spa.s_net, ea->aarp_spnet, sizeof(spa.s_net));
386 		memcpy(&tpa.s_net, ea->aarp_tpnet, sizeof(tpa.s_net));
387 	} else {
388 		/*
389 		 * Since we don't know the net, we just look for the first
390 		 * phase 1 address on the interface.
391 		 */
392 		s = pserialize_read_enter();
393 		IFADDR_READER_FOREACH(ifa, ifp) {
394 			aa = (struct at_ifaddr *)ifa;
395 			if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
396 			    (aa->aa_flags & AFA_PHASE2) == 0) {
397 				ifa_acquire(ifa, &psref);
398 				break;
399 			}
400 		}
401 		pserialize_read_exit(s);
402 
403 		if (ifa == NULL) {
404 			m_freem(m);
405 			return;
406 		}
407 		tpa.s_net = spa.s_net = AA_SAT(aa)->sat_addr.s_net;
408 	}
409 
410 	spa.s_node = ea->aarp_spnode;
411 	tpa.s_node = ea->aarp_tpnode;
412 	ma.s_net = AA_SAT(aa)->sat_addr.s_net;
413 	ma.s_node = AA_SAT(aa)->sat_addr.s_node;
414 
415 	/*
416          * This looks like it's from us.
417          */
418 	if (spa.s_net == ma.s_net && spa.s_node == ma.s_node) {
419 		if (aa->aa_flags & AFA_PROBING) {
420 			/*
421 		         * We're probing, someone either responded to our
422 			 * probe, or probed for the same address we'd like
423 			 * to use. Change the address we're probing for.
424 		         */
425 			callout_stop(&aa->aa_probe_ch);
426 			wakeup(aa);
427 			m_freem(m);
428 			goto out;
429 		} else if (op != AARPOP_PROBE) {
430 			/*
431 		         * This is not a probe, and we're not probing.
432 			 * This means that someone's saying they have the same
433 			 * source address as the one we're using. Get upset...
434 		         */
435 			log(LOG_ERR, "aarp: duplicate AT address!! %s\n",
436 			    ether_sprintf(ea->aarp_sha));
437 			m_freem(m);
438 			goto out;
439 		}
440 	}
441 	AARPTAB_LOOK(aat, spa);
442 	if (aat) {
443 		if (op == AARPOP_PROBE) {
444 			/*
445 		         * Someone's probing for spa, deallocate the one we've
446 			 * got, so that if the prober keeps the address, we'll
447 			 * be able to arp for him.
448 		         */
449 			aarptfree(aat);
450 			m_freem(m);
451 			goto out;
452 		}
453 		memcpy(aat->aat_enaddr, ea->aarp_sha, sizeof(ea->aarp_sha));
454 		aat->aat_flags |= ATF_COM;
455 		if (aat->aat_hold) {
456 			sat.sat_len = sizeof(struct sockaddr_at);
457 			sat.sat_family = AF_APPLETALK;
458 			sat.sat_addr = spa;
459 			if_output_lock(ifp, ifp, aat->aat_hold,
460 			    (struct sockaddr *) & sat, NULL);	/* XXX */
461 			aat->aat_hold = 0;
462 		}
463 	}
464 	if (aat == 0 && tpa.s_net == ma.s_net && tpa.s_node == ma.s_node
465 	    && op != AARPOP_PROBE) {
466 		if ((aat = aarptnew(&spa)) != NULL) {
467 			memcpy(aat->aat_enaddr, ea->aarp_sha,
468 			    sizeof(ea->aarp_sha));
469 			aat->aat_flags |= ATF_COM;
470 		}
471 	}
472 	/*
473          * Don't respond to responses, and never respond if we're
474          * still probing.
475          */
476 	if (tpa.s_net != ma.s_net || tpa.s_node != ma.s_node ||
477 	    op == AARPOP_RESPONSE || (aa->aa_flags & AFA_PROBING)) {
478 		m_freem(m);
479 		goto out;
480 	}
481 
482 	/*
483 	 * Prepare and send AARP-response.
484 	 */
485 	m->m_len = sizeof(*ea);
486 	m->m_pkthdr.len = sizeof(*ea);
487 	memcpy(ea->aarp_tha, ea->aarp_sha, sizeof(ea->aarp_sha));
488 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
489 
490 	/* XXX */
491 	eh = (struct ether_header *) sa.sa_data;
492 	memcpy(eh->ether_dhost, ea->aarp_tha, sizeof(eh->ether_dhost));
493 
494 	if (aa->aa_flags & AFA_PHASE2) {
495 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
496 		if (m == NULL)
497 			goto out;
498 
499 		llc = mtod(m, struct llc *);
500 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
501 		llc->llc_control = LLC_UI;
502 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
503 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
504 
505 		memcpy(ea->aarp_tpnet, ea->aarp_spnet, sizeof(ea->aarp_tpnet));
506 		memcpy(ea->aarp_spnet, &ma.s_net, sizeof(ea->aarp_spnet));
507 		eh->ether_type = 0;	/* if_output will treat as 802 */
508 	} else {
509 		eh->ether_type = htons(ETHERTYPE_AARP);
510 	}
511 
512 	ea->aarp_tpnode = ea->aarp_spnode;
513 	ea->aarp_spnode = ma.s_node;
514 	ea->aarp_op = htons(AARPOP_RESPONSE);
515 
516 	sa.sa_len = sizeof(struct sockaddr);
517 	sa.sa_family = AF_UNSPEC;
518 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
519 out:
520 	ifa_release(ifa, &psref);
521 	return;
522 }
523 
524 static void
525 aarptfree(struct aarptab *aat)
526 {
527 
528 	if (aat->aat_hold)
529 		m_freem(aat->aat_hold);
530 	aat->aat_hold = 0;
531 	aat->aat_timer = aat->aat_flags = 0;
532 	aat->aat_ataddr.s_net = 0;
533 	aat->aat_ataddr.s_node = 0;
534 }
535 
536 static struct aarptab *
537 aarptnew(const struct at_addr *addr)
538 {
539 	int             n;
540 	int             oldest = -1;
541 	struct aarptab *aat, *aato = NULL;
542 	static int      first = 1;
543 
544 	if (first) {
545 		first = 0;
546 		callout_init(&aarptimer_callout, 0);
547 		callout_reset(&aarptimer_callout, hz, aarptimer, NULL);
548 	}
549 	aat = &aarptab[AARPTAB_HASH(*addr) * AARPTAB_BSIZ];
550 	for (n = 0; n < AARPTAB_BSIZ; n++, aat++) {
551 		if (aat->aat_flags == 0)
552 			goto out;
553 		if (aat->aat_flags & ATF_PERM)
554 			continue;
555 		if ((int) aat->aat_timer > oldest) {
556 			oldest = aat->aat_timer;
557 			aato = aat;
558 		}
559 	}
560 	if (aato == NULL)
561 		return (NULL);
562 	aat = aato;
563 	aarptfree(aat);
564 out:
565 	aat->aat_ataddr = *addr;
566 	aat->aat_flags = ATF_INUSE;
567 	return (aat);
568 }
569 
570 
571 void
572 aarpprobe(void *arp)
573 {
574 	struct mbuf    *m;
575 	struct ether_header *eh;
576 	struct ether_aarp *ea;
577 	struct ifaddr *ia;
578 	struct at_ifaddr *aa;
579 	struct llc     *llc;
580 	struct sockaddr sa;
581 	struct ifnet   *ifp = arp;
582 
583 	mutex_enter(softnet_lock);
584 
585 	/*
586          * We need to check whether the output ethernet type should
587          * be phase 1 or 2. We have the interface that we'll be sending
588          * the aarp out. We need to find an AppleTalk network on that
589          * interface with the same address as we're looking for. If the
590          * net is phase 2, generate an 802.2 and SNAP header.
591          */
592 	IFADDR_READER_FOREACH(ia, ifp) {
593 		aa = (struct at_ifaddr *)ia;
594 		if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
595 		    (aa->aa_flags & AFA_PROBING))
596 			break;
597 	}
598 	if (ia == NULL) {	/* serious error XXX */
599 		printf("aarpprobe why did this happen?!\n");
600 		mutex_exit(softnet_lock);
601 		return;
602 	}
603 	if (aa->aa_probcnt <= 0) {
604 		aa->aa_flags &= ~AFA_PROBING;
605 		wakeup(aa);
606 		mutex_exit(softnet_lock);
607 		return;
608 	} else {
609 		callout_reset(&aa->aa_probe_ch, hz / 5, aarpprobe, arp);
610 	}
611 
612 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) {
613 		mutex_exit(softnet_lock);
614 		return;
615 	}
616 
617 	MCLAIM(m, &aarp_mowner);
618 	m->m_len = sizeof(*ea);
619 	m->m_pkthdr.len = sizeof(*ea);
620 	MH_ALIGN(m, sizeof(*ea));
621 
622 	ea = mtod(m, struct ether_aarp *);
623 	memset(ea, 0, sizeof(*ea));
624 
625 	ea->aarp_hrd = htons(AARPHRD_ETHER);
626 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
627 	ea->aarp_hln = sizeof(ea->aarp_sha);
628 	ea->aarp_pln = sizeof(ea->aarp_spu);
629 	ea->aarp_op = htons(AARPOP_PROBE);
630 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
631 
632 	eh = (struct ether_header *) sa.sa_data;
633 
634 	if (aa->aa_flags & AFA_PHASE2) {
635 		memcpy(eh->ether_dhost, atmulticastaddr,
636 		    sizeof(eh->ether_dhost));
637 		eh->ether_type = 0;	/* if_output will treat as 802 */
638 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
639 		if (!m) {
640 			mutex_exit(softnet_lock);
641 			return;
642 		}
643 
644 		llc = mtod(m, struct llc *);
645 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
646 		llc->llc_control = LLC_UI;
647 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
648 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
649 
650 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
651 		      sizeof(ea->aarp_spnet));
652 		memcpy(ea->aarp_tpnet, &AA_SAT(aa)->sat_addr.s_net,
653 		      sizeof(ea->aarp_tpnet));
654 		ea->aarp_spnode = ea->aarp_tpnode =
655 		    AA_SAT(aa)->sat_addr.s_node;
656 	} else {
657 		memcpy(eh->ether_dhost, etherbroadcastaddr,
658 		    sizeof(eh->ether_dhost));
659 		eh->ether_type = htons(ETHERTYPE_AARP);
660 		ea->aarp_spa = ea->aarp_tpa = AA_SAT(aa)->sat_addr.s_node;
661 	}
662 
663 #ifdef NETATALKDEBUG
664 	printf("aarp: sending probe for %u.%u\n",
665 	       ntohs(AA_SAT(aa)->sat_addr.s_net),
666 	       AA_SAT(aa)->sat_addr.s_node);
667 #endif	/* NETATALKDEBUG */
668 
669 	sa.sa_len = sizeof(struct sockaddr);
670 	sa.sa_family = AF_UNSPEC;
671 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
672 	aa->aa_probcnt--;
673 	mutex_exit(softnet_lock);
674 }
675 
676 void
677 aarp_clean(void)
678 {
679 	struct aarptab *aat;
680 	int             i;
681 
682 	callout_stop(&aarptimer_callout);
683 	for (i = 0, aat = aarptab; i < AARPTAB_SIZE; i++, aat++)
684 		if (aat->aat_hold)
685 			m_freem(aat->aat_hold);
686 }
687