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aarp.c revision 1.38
      1 /*	$NetBSD: aarp.c,v 1.38 2016/07/07 09:32:02 ozaki-r 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 1.38 2016/07/07 09:32:02 ozaki-r 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 	return ifa;
    153 }
    154 
    155 static void
    156 aarpwhohas(struct ifnet *ifp, const struct sockaddr_at *sat)
    157 {
    158 	struct mbuf    *m;
    159 	struct ether_header *eh;
    160 	struct ether_aarp *ea;
    161 	struct at_ifaddr *aa;
    162 	struct llc     *llc;
    163 	struct sockaddr sa;
    164 
    165 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
    166 		return;
    167 
    168 	MCLAIM(m, &aarp_mowner);
    169 	m->m_len = sizeof(*ea);
    170 	m->m_pkthdr.len = sizeof(*ea);
    171 	MH_ALIGN(m, sizeof(*ea));
    172 
    173 	ea = mtod(m, struct ether_aarp *);
    174 	memset(ea, 0, sizeof(*ea));
    175 
    176 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    177 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    178 	ea->aarp_hln = sizeof(ea->aarp_sha);
    179 	ea->aarp_pln = sizeof(ea->aarp_spu);
    180 	ea->aarp_op = htons(AARPOP_REQUEST);
    181 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
    182 
    183 	/*
    184          * We need to check whether the output ethernet type should
    185          * be phase 1 or 2. We have the interface that we'll be sending
    186          * the aarp out. We need to find an AppleTalk network on that
    187          * interface with the same address as we're looking for. If the
    188          * net is phase 2, generate an 802.2 and SNAP header.
    189          */
    190 	if ((aa = (struct at_ifaddr *) at_ifawithnet(sat, ifp)) == NULL) {
    191 		m_freem(m);
    192 		return;
    193 	}
    194 	eh = (struct ether_header *) sa.sa_data;
    195 
    196 	if (aa->aa_flags & AFA_PHASE2) {
    197 		memcpy(eh->ether_dhost, atmulticastaddr,
    198 		    sizeof(eh->ether_dhost));
    199 		eh->ether_type = 0;	/* if_output will treat as 802 */
    200 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    201 		if (!m)
    202 			return;
    203 
    204 		llc = mtod(m, struct llc *);
    205 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    206 		llc->llc_control = LLC_UI;
    207 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
    208 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    209 
    210 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
    211 		      sizeof(ea->aarp_spnet));
    212 		memcpy(ea->aarp_tpnet, &sat->sat_addr.s_net,
    213 		      sizeof(ea->aarp_tpnet));
    214 		ea->aarp_spnode = AA_SAT(aa)->sat_addr.s_node;
    215 		ea->aarp_tpnode = sat->sat_addr.s_node;
    216 	} else {
    217 		memcpy(eh->ether_dhost, etherbroadcastaddr,
    218 		    sizeof(eh->ether_dhost));
    219 		eh->ether_type = htons(ETHERTYPE_AARP);
    220 
    221 		ea->aarp_spa = AA_SAT(aa)->sat_addr.s_node;
    222 		ea->aarp_tpa = sat->sat_addr.s_node;
    223 	}
    224 
    225 	/* If we are talking to ourselves, use the loopback interface. */
    226 	if (AA_SAT(aa)->sat_addr.s_net == sat->sat_addr.s_net &&
    227 	    AA_SAT(aa)->sat_addr.s_node == sat->sat_addr.s_node)
    228 		ifp = lo0ifp;
    229 
    230 #ifdef NETATALKDEBUG
    231 	printf("aarp: sending request via %u.%u through %s seeking %u.%u\n",
    232 	    ntohs(AA_SAT(aa)->sat_addr.s_net),
    233 	    AA_SAT(aa)->sat_addr.s_node,
    234 	    ifp->if_xname,
    235 	    ntohs(sat->sat_addr.s_net),
    236 	    sat->sat_addr.s_node);
    237 #endif /* NETATALKDEBUG */
    238 
    239 	sa.sa_len = sizeof(struct sockaddr);
    240 	sa.sa_family = AF_UNSPEC;
    241 	if_output_lock(ifp, ifp, m, &sa, NULL);	/* XXX NULL should be routing */
    242 						/* information */
    243 }
    244 
    245 int
    246 aarpresolve(struct ifnet *ifp, struct mbuf *m,
    247     const struct sockaddr_at *destsat, u_char *desten)
    248 {
    249 	struct at_ifaddr *aa;
    250 	struct aarptab *aat;
    251 	int             s;
    252 
    253 	if (at_broadcast(destsat)) {
    254 		aa = (struct at_ifaddr *) at_ifawithnet(destsat, ifp);
    255 		if (aa == NULL) {
    256 			m_freem(m);
    257 			return (0);
    258 		}
    259 		if (aa->aa_flags & AFA_PHASE2)
    260 			memcpy(desten, atmulticastaddr,
    261 			    sizeof(atmulticastaddr));
    262 		else
    263 			memcpy(desten, etherbroadcastaddr,
    264 			    sizeof(etherbroadcastaddr));
    265 		return 1;
    266 	}
    267 	s = splnet();
    268 	AARPTAB_LOOK(aat, destsat->sat_addr);
    269 	if (aat == 0) {		/* No entry */
    270 		aat = aarptnew(&destsat->sat_addr);
    271 		if (aat == 0)
    272 			panic("aarpresolve: no free entry");
    273 
    274 		aat->aat_hold = m;
    275 		aarpwhohas(ifp, destsat);
    276 		splx(s);
    277 		return 0;
    278 	}
    279 
    280 	/* found an entry */
    281 	aat->aat_timer = 0;
    282 	if (aat->aat_flags & ATF_COM) {	/* entry is COMplete */
    283 		memcpy(desten, aat->aat_enaddr, sizeof(aat->aat_enaddr));
    284 		splx(s);
    285 		return 1;
    286 	}
    287 
    288 	/* entry has not completed */
    289 	if (aat->aat_hold)
    290 		m_freem(aat->aat_hold);
    291 	aat->aat_hold = m;
    292 	aarpwhohas(ifp, destsat);
    293 	splx(s);
    294 
    295 	return 0;
    296 }
    297 
    298 void
    299 aarpinput(struct ifnet *ifp, struct mbuf *m)
    300 {
    301 	struct arphdr  *ar;
    302 
    303 	if (ifp->if_flags & IFF_NOARP)
    304 		goto out;
    305 
    306 	if (m->m_len < sizeof(struct arphdr))
    307 		goto out;
    308 
    309 	ar = mtod(m, struct arphdr *);
    310 	if (ntohs(ar->ar_hrd) != AARPHRD_ETHER)
    311 		goto out;
    312 
    313 	if (m->m_len < sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
    314 		goto out;
    315 
    316 	switch (ntohs(ar->ar_pro)) {
    317 	case ETHERTYPE_ATALK:
    318 		at_aarpinput(ifp, m);
    319 		return;
    320 
    321 	default:
    322 		break;
    323 	}
    324 
    325 out:
    326 	m_freem(m);
    327 }
    328 
    329 static void
    330 at_aarpinput(struct ifnet *ifp, struct mbuf *m)
    331 {
    332 	struct ether_aarp *ea;
    333 	struct at_ifaddr *aa;
    334 	struct ifaddr *ia;
    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 (!memcmp(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha))) {
    348 		m_freem(m);
    349 		return;
    350 	}
    351 	op = ntohs(ea->aarp_op);
    352 	memcpy(&net, ea->aarp_tpnet, 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 		memcpy(&spa.s_net, ea->aarp_spnet, sizeof(spa.s_net));
    364 		memcpy(&tpa.s_net, ea->aarp_tpnet, 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 		IFADDR_READER_FOREACH(ia, ifp) {
    371 			aa = (struct at_ifaddr *)ia;
    372 			if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    373 			    (aa->aa_flags & AFA_PHASE2) == 0)
    374 				break;
    375 		}
    376 		if (ia == 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 		memcpy(aat->aat_enaddr, ea->aarp_sha, 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 			if_output_lock(ifp, 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 			memcpy(aat->aat_enaddr, ea->aarp_sha,
    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 
    455 	/*
    456 	 * Prepare and send AARP-response.
    457 	 */
    458 	m->m_len = sizeof(*ea);
    459 	m->m_pkthdr.len = sizeof(*ea);
    460 	memcpy(ea->aarp_tha, ea->aarp_sha, sizeof(ea->aarp_sha));
    461 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
    462 
    463 	/* XXX */
    464 	eh = (struct ether_header *) sa.sa_data;
    465 	memcpy(eh->ether_dhost, ea->aarp_tha, sizeof(eh->ether_dhost));
    466 
    467 	if (aa->aa_flags & AFA_PHASE2) {
    468 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    469 		if (m == NULL)
    470 			return;
    471 
    472 		llc = mtod(m, struct llc *);
    473 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    474 		llc->llc_control = LLC_UI;
    475 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
    476 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    477 
    478 		memcpy(ea->aarp_tpnet, ea->aarp_spnet, sizeof(ea->aarp_tpnet));
    479 		memcpy(ea->aarp_spnet, &ma.s_net, sizeof(ea->aarp_spnet));
    480 		eh->ether_type = 0;	/* if_output will treat as 802 */
    481 	} else {
    482 		eh->ether_type = htons(ETHERTYPE_AARP);
    483 	}
    484 
    485 	ea->aarp_tpnode = ea->aarp_spnode;
    486 	ea->aarp_spnode = ma.s_node;
    487 	ea->aarp_op = htons(AARPOP_RESPONSE);
    488 
    489 	sa.sa_len = sizeof(struct sockaddr);
    490 	sa.sa_family = AF_UNSPEC;
    491 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    492 	return;
    493 }
    494 
    495 static void
    496 aarptfree(struct aarptab *aat)
    497 {
    498 
    499 	if (aat->aat_hold)
    500 		m_freem(aat->aat_hold);
    501 	aat->aat_hold = 0;
    502 	aat->aat_timer = aat->aat_flags = 0;
    503 	aat->aat_ataddr.s_net = 0;
    504 	aat->aat_ataddr.s_node = 0;
    505 }
    506 
    507 static struct aarptab *
    508 aarptnew(const struct at_addr *addr)
    509 {
    510 	int             n;
    511 	int             oldest = -1;
    512 	struct aarptab *aat, *aato = NULL;
    513 	static int      first = 1;
    514 
    515 	if (first) {
    516 		first = 0;
    517 		callout_init(&aarptimer_callout, 0);
    518 		callout_reset(&aarptimer_callout, hz, aarptimer, NULL);
    519 	}
    520 	aat = &aarptab[AARPTAB_HASH(*addr) * AARPTAB_BSIZ];
    521 	for (n = 0; n < AARPTAB_BSIZ; n++, aat++) {
    522 		if (aat->aat_flags == 0)
    523 			goto out;
    524 		if (aat->aat_flags & ATF_PERM)
    525 			continue;
    526 		if ((int) aat->aat_timer > oldest) {
    527 			oldest = aat->aat_timer;
    528 			aato = aat;
    529 		}
    530 	}
    531 	if (aato == NULL)
    532 		return (NULL);
    533 	aat = aato;
    534 	aarptfree(aat);
    535 out:
    536 	aat->aat_ataddr = *addr;
    537 	aat->aat_flags = ATF_INUSE;
    538 	return (aat);
    539 }
    540 
    541 
    542 void
    543 aarpprobe(void *arp)
    544 {
    545 	struct mbuf    *m;
    546 	struct ether_header *eh;
    547 	struct ether_aarp *ea;
    548 	struct ifaddr *ia;
    549 	struct at_ifaddr *aa;
    550 	struct llc     *llc;
    551 	struct sockaddr sa;
    552 	struct ifnet   *ifp = arp;
    553 
    554 	mutex_enter(softnet_lock);
    555 
    556 	/*
    557          * We need to check whether the output ethernet type should
    558          * be phase 1 or 2. We have the interface that we'll be sending
    559          * the aarp out. We need to find an AppleTalk network on that
    560          * interface with the same address as we're looking for. If the
    561          * net is phase 2, generate an 802.2 and SNAP header.
    562          */
    563 	IFADDR_READER_FOREACH(ia, ifp) {
    564 		aa = (struct at_ifaddr *)ia;
    565 		if (AA_SAT(aa)->sat_family == AF_APPLETALK &&
    566 		    (aa->aa_flags & AFA_PROBING))
    567 			break;
    568 	}
    569 	if (ia == NULL) {	/* serious error XXX */
    570 		printf("aarpprobe why did this happen?!\n");
    571 		mutex_exit(softnet_lock);
    572 		return;
    573 	}
    574 	if (aa->aa_probcnt <= 0) {
    575 		aa->aa_flags &= ~AFA_PROBING;
    576 		wakeup(aa);
    577 		mutex_exit(softnet_lock);
    578 		return;
    579 	} else {
    580 		callout_reset(&aa->aa_probe_ch, hz / 5, aarpprobe, arp);
    581 	}
    582 
    583 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) {
    584 		mutex_exit(softnet_lock);
    585 		return;
    586 	}
    587 
    588 	MCLAIM(m, &aarp_mowner);
    589 	m->m_len = sizeof(*ea);
    590 	m->m_pkthdr.len = sizeof(*ea);
    591 	MH_ALIGN(m, sizeof(*ea));
    592 
    593 	ea = mtod(m, struct ether_aarp *);
    594 	memset(ea, 0, sizeof(*ea));
    595 
    596 	ea->aarp_hrd = htons(AARPHRD_ETHER);
    597 	ea->aarp_pro = htons(ETHERTYPE_ATALK);
    598 	ea->aarp_hln = sizeof(ea->aarp_sha);
    599 	ea->aarp_pln = sizeof(ea->aarp_spu);
    600 	ea->aarp_op = htons(AARPOP_PROBE);
    601 	memcpy(ea->aarp_sha, CLLADDR(ifp->if_sadl), sizeof(ea->aarp_sha));
    602 
    603 	eh = (struct ether_header *) sa.sa_data;
    604 
    605 	if (aa->aa_flags & AFA_PHASE2) {
    606 		memcpy(eh->ether_dhost, atmulticastaddr,
    607 		    sizeof(eh->ether_dhost));
    608 		eh->ether_type = 0;	/* if_output will treat as 802 */
    609 		M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
    610 		if (!m) {
    611 			mutex_exit(softnet_lock);
    612 			return;
    613 		}
    614 
    615 		llc = mtod(m, struct llc *);
    616 		llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    617 		llc->llc_control = LLC_UI;
    618 		memcpy(llc->llc_org_code, aarp_org_code, sizeof(aarp_org_code));
    619 		llc->llc_ether_type = htons(ETHERTYPE_AARP);
    620 
    621 		memcpy(ea->aarp_spnet, &AA_SAT(aa)->sat_addr.s_net,
    622 		      sizeof(ea->aarp_spnet));
    623 		memcpy(ea->aarp_tpnet, &AA_SAT(aa)->sat_addr.s_net,
    624 		      sizeof(ea->aarp_tpnet));
    625 		ea->aarp_spnode = ea->aarp_tpnode =
    626 		    AA_SAT(aa)->sat_addr.s_node;
    627 	} else {
    628 		memcpy(eh->ether_dhost, etherbroadcastaddr,
    629 		    sizeof(eh->ether_dhost));
    630 		eh->ether_type = htons(ETHERTYPE_AARP);
    631 		ea->aarp_spa = ea->aarp_tpa = AA_SAT(aa)->sat_addr.s_node;
    632 	}
    633 
    634 #ifdef NETATALKDEBUG
    635 	printf("aarp: sending probe for %u.%u\n",
    636 	       ntohs(AA_SAT(aa)->sat_addr.s_net),
    637 	       AA_SAT(aa)->sat_addr.s_node);
    638 #endif	/* NETATALKDEBUG */
    639 
    640 	sa.sa_len = sizeof(struct sockaddr);
    641 	sa.sa_family = AF_UNSPEC;
    642 	(*ifp->if_output) (ifp, m, &sa, NULL);	/* XXX */
    643 	aa->aa_probcnt--;
    644 	mutex_exit(softnet_lock);
    645 }
    646 
    647 void
    648 aarp_clean(void)
    649 {
    650 	struct aarptab *aat;
    651 	int             i;
    652 
    653 	callout_stop(&aarptimer_callout);
    654 	for (i = 0, aat = aarptab; i < AARPTAB_SIZE; i++, aat++)
    655 		if (aat->aat_hold)
    656 			m_freem(aat->aat_hold);
    657 }
    658