xref: /netbsd-src/sys/net/if_arcsubr.c (revision 21a3d2f02241c56556f4b2305ef1b8036f268f70)
1 /*	$NetBSD: if_arcsubr.c,v 1.37 2001/10/17 08:23:05 itojun Exp $	*/
2 
3 /*
4  * Copyright (c) 1994, 1995 Ignatios Souvatzis
5  * Copyright (c) 1982, 1989, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  * from: NetBSD: if_ethersubr.c,v 1.9 1994/06/29 06:36:11 cgd Exp
37  *       @(#)if_ethersubr.c	8.1 (Berkeley) 6/10/93
38  *
39  */
40 #include "opt_inet.h"
41 
42 #include "bpfilter.h"
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/malloc.h>
48 #include <sys/mbuf.h>
49 #include <sys/protosw.h>
50 #include <sys/socket.h>
51 #include <sys/ioctl.h>
52 #include <sys/errno.h>
53 #include <sys/syslog.h>
54 
55 #include <machine/cpu.h>
56 
57 #include <net/if.h>
58 #include <net/netisr.h>
59 #include <net/route.h>
60 #include <net/if_dl.h>
61 #include <net/if_types.h>
62 #include <net/if_arc.h>
63 #include <net/if_arp.h>
64 #include <net/if_ether.h>
65 
66 #if NBPFILTER > 0
67 #include <net/bpf.h>
68 #endif
69 
70 #ifdef INET
71 #include <netinet/in.h>
72 #include <netinet/in_var.h>
73 #include <netinet/if_inarp.h>
74 #endif
75 
76 #ifdef INET6
77 #ifndef INET
78 #include <netinet/in.h>
79 #endif
80 #include <netinet6/in6_var.h>
81 #include <netinet6/nd6.h>
82 #endif
83 
84 #define ARCNET_ALLOW_BROKEN_ARP
85 
86 #ifndef ARC_IPMTU
87 #define ARC_IPMTU	1500
88 #endif
89 
90 static struct mbuf *arc_defrag __P((struct ifnet *, struct mbuf *));
91 
92 /*
93  * RC1201 requires us to have this configurable. We have it only per
94  * machine at the moment... there is no generic "set mtu" ioctl, AFAICS.
95  * Anyway, it is possible to binpatch this or set it per kernel config
96  * option.
97  */
98 #if ARC_IPMTU > 60480
99 ERROR: The arc_ipmtu is ARC_IPMTU, but must not exceed 60480.
100 #endif
101 int arc_ipmtu = ARC_IPMTU;
102 u_int8_t  arcbroadcastaddr = 0;
103 
104 #define senderr(e) { error = (e); goto bad;}
105 #define SIN(s) ((struct sockaddr_in *)s)
106 
107 static	int arc_output __P((struct ifnet *, struct mbuf *,
108 	    struct sockaddr *, struct rtentry *));
109 static	void arc_input __P((struct ifnet *, struct mbuf *));
110 
111 /*
112  * ARCnet output routine.
113  * Encapsulate a packet of type family for the local net.
114  * Assumes that ifp is actually pointer to arccom structure.
115  */
116 static int
117 arc_output(ifp, m0, dst, rt0)
118 	struct ifnet *ifp;
119 	struct mbuf *m0;
120 	struct sockaddr *dst;
121 	struct rtentry *rt0;
122 {
123 	struct mbuf		*m, *m1, *mcopy;
124 	struct rtentry		*rt;
125 	struct arccom		*ac;
126 	struct arc_header	*ah;
127 	struct arphdr		*arph;
128 	int			s, error, newencoding;
129 	u_int8_t		atype, adst, myself;
130 	int			tfrags, sflag, fsflag, rsflag;
131 
132 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
133 		return(ENETDOWN); /* m, m1 aren't initialized yet */
134 
135 	error = newencoding = 0;
136 	ac = (struct arccom *)ifp;
137 	m = m0;
138 	mcopy = m1 = NULL;
139 
140 	myself = *LLADDR(ifp->if_sadl);
141 
142 	if ((rt = rt0)) {
143 		if ((rt->rt_flags & RTF_UP) == 0) {
144 			if ((rt0 = rt = rtalloc1(dst, 1)))
145 				rt->rt_refcnt--;
146 			else
147 				senderr(EHOSTUNREACH);
148 		}
149 		if (rt->rt_flags & RTF_GATEWAY) {
150 			if (rt->rt_gwroute == 0)
151 				goto lookup;
152 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
153 				rtfree(rt); rt = rt0;
154 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
155 				if ((rt = rt->rt_gwroute) == 0)
156 					senderr(EHOSTUNREACH);
157 			}
158 		}
159 		if (rt->rt_flags & RTF_REJECT)
160 			if (rt->rt_rmx.rmx_expire == 0 ||
161 			    time.tv_sec < rt->rt_rmx.rmx_expire)
162 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
163 	}
164 
165 	switch (dst->sa_family) {
166 #ifdef INET
167 	case AF_INET:
168 
169 		/*
170 		 * For now, use the simple IP addr -> ARCnet addr mapping
171 		 */
172 		if (m->m_flags & (M_BCAST|M_MCAST))
173 			adst = arcbroadcastaddr; /* ARCnet broadcast address */
174 		else if (ifp->if_flags & IFF_NOARP)
175 			adst = ntohl(SIN(dst)->sin_addr.s_addr) & 0xFF;
176 		else if (!arpresolve(ifp, rt, m, dst, &adst))
177 			return 0;	/* not resolved yet */
178 
179 		/* If broadcasting on a simplex interface, loopback a copy */
180 		if ((m->m_flags & (M_BCAST|M_MCAST)) &&
181 		    (ifp->if_flags & IFF_SIMPLEX))
182 			mcopy = m_copy(m, 0, (int)M_COPYALL);
183 		if (ifp->if_flags & IFF_LINK0) {
184 			atype = ARCTYPE_IP;
185 			newencoding = 1;
186 		} else {
187 			atype = ARCTYPE_IP_OLD;
188 			newencoding = 0;
189 		}
190 		break;
191 
192 	case AF_ARP:
193 		arph = mtod(m, struct arphdr *);
194 		if (m->m_flags & M_BCAST)
195 			adst = arcbroadcastaddr;
196 		else
197 			adst = *ar_tha(arph);
198 
199 		arph->ar_hrd = htons(ARPHRD_ARCNET);
200 
201 		switch(ntohs(arph->ar_op)) {
202 
203 		case ARPOP_REVREQUEST:
204 		case ARPOP_REVREPLY:
205 			if (!(ifp->if_flags & IFF_LINK0)) {
206 				printf("%s: can't handle af%d\n",
207 				    ifp->if_xname, dst->sa_family);
208 				senderr(EAFNOSUPPORT);
209 			}
210 
211 			atype = htons(ARCTYPE_REVARP);
212 			newencoding = 1;
213 			break;
214 
215 		case ARPOP_REQUEST:
216 		case ARPOP_REPLY:
217 		default:
218 			if (ifp->if_flags & IFF_LINK0) {
219 				atype = htons(ARCTYPE_ARP);
220 				newencoding = 1;
221 			} else {
222 				atype = htons(ARCTYPE_ARP_OLD);
223 				newencoding = 0;
224 			}
225 		}
226 #ifdef ARCNET_ALLOW_BROKEN_ARP
227 		/*
228 		 * XXX It's not clear per RFC826 if this is needed, but
229 		 * "assigned numbers" say this is wrong.
230 		 * However, e.g., AmiTCP 3.0Beta used it... we make this
231 		 * switchable for emergency cases. Not perfect, but...
232 		 */
233 		if (ifp->if_flags & IFF_LINK2)
234 			arph->ar_pro = atype - 1;
235 #endif
236 		break;
237 #endif
238 #ifdef INET6
239 	case AF_INET6:
240 		if (!nd6_storelladdr(ifp, rt, m, dst, (u_char *)&adst))
241 			return(0); /* it must be impossible, but... */
242 		atype = htons(ARCTYPE_INET6);
243 		newencoding = 1;
244 		break;
245 #endif
246 
247 	case AF_UNSPEC:
248 		ah = (struct arc_header *)dst->sa_data;
249  		adst = ah->arc_dhost;
250 		atype = ah->arc_type;
251 		break;
252 
253 	default:
254 		printf("%s: can't handle af%d\n", ifp->if_xname,
255 		    dst->sa_family);
256 		senderr(EAFNOSUPPORT);
257 	}
258 
259 	if (mcopy)
260 		(void) looutput(ifp, mcopy, dst, rt);
261 
262 	/*
263 	 * Add local net header.  If no space in first mbuf,
264 	 * allocate another.
265 	 *
266 	 * For ARCnet, this is just symbolic. The header changes
267 	 * form and position on its way into the hardware and out of
268 	 * the wire.  At this point, it contains source, destination and
269 	 * packet type.
270 	 */
271 	if (newencoding) {
272 		++ac->ac_seqid; /* make the seqid unique */
273 
274 		tfrags = (m->m_pkthdr.len + 503) / 504;
275 		fsflag = 2 * tfrags - 3;
276 		sflag = 0;
277 		rsflag = fsflag;
278 
279 		while (sflag < fsflag) {
280 			/* we CAN'T have short packets here */
281 			m1 = m_split(m, 504, M_DONTWAIT);
282 			if (m1 == 0)
283 				senderr(ENOBUFS);
284 
285 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
286 			if (m == 0)
287 				senderr(ENOBUFS);
288 			ah = mtod(m, struct arc_header *);
289 			ah->arc_type = atype;
290 			ah->arc_dhost = adst;
291 			ah->arc_shost = myself;
292 			ah->arc_flag = rsflag;
293 			ah->arc_seqid = ac->ac_seqid;
294 
295 			s = splnet();
296 			/*
297 			 * Queue message on interface, and start output if
298 			 * interface not yet active.
299 			 */
300 			if (IF_QFULL(&ifp->if_snd)) {
301 				IF_DROP(&ifp->if_snd);
302 				splx(s);
303 				senderr(ENOBUFS);
304 			}
305 			ifp->if_obytes += m->m_pkthdr.len;
306 			IF_ENQUEUE(&ifp->if_snd, m);
307 			if ((ifp->if_flags & IFF_OACTIVE) == 0)
308 				(*ifp->if_start)(ifp);
309 			splx(s);
310 
311 			m = m1;
312 			sflag += 2;
313 			rsflag = sflag;
314 		}
315 		m1 = NULL;
316 
317 
318 		/* here we can have small, especially forbidden packets */
319 
320 		if ((m->m_pkthdr.len >=
321 		    ARC_MIN_FORBID_LEN - ARC_HDRNEWLEN + 2) &&
322 		    (m->m_pkthdr.len <=
323 		    ARC_MAX_FORBID_LEN - ARC_HDRNEWLEN + 2)) {
324 
325 			M_PREPEND(m, ARC_HDRNEWLEN_EXC, M_DONTWAIT);
326 			if (m == 0)
327 				senderr(ENOBUFS);
328 			ah = mtod(m, struct arc_header *);
329 			ah->arc_flag = 0xFF;
330 			ah->arc_seqid = 0xFFFF;
331 			ah->arc_type2 = atype;
332 			ah->arc_flag2 = sflag;
333 			ah->arc_seqid2 = ac->ac_seqid;
334 		} else {
335 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
336 			if (m == 0)
337 				senderr(ENOBUFS);
338 			ah = mtod(m, struct arc_header *);
339 			ah->arc_flag = sflag;
340 			ah->arc_seqid = ac->ac_seqid;
341 		}
342 
343 		ah->arc_dhost = adst;
344 		ah->arc_shost = myself;
345 		ah->arc_type = atype;
346 	} else {
347 		M_PREPEND(m, ARC_HDRLEN, M_DONTWAIT);
348 		if (m == 0)
349 			senderr(ENOBUFS);
350 		ah = mtod(m, struct arc_header *);
351 		ah->arc_type = atype;
352 		ah->arc_dhost = adst;
353 		ah->arc_shost = myself;
354 	}
355 	s = splnet();
356 	/*
357 	 * Queue message on interface, and start output if interface
358 	 * not yet active.
359 	 */
360 	if (IF_QFULL(&ifp->if_snd)) {
361 		IF_DROP(&ifp->if_snd);
362 		splx(s);
363 		senderr(ENOBUFS);
364 	}
365 	ifp->if_obytes += m->m_pkthdr.len;
366 	IF_ENQUEUE(&ifp->if_snd, m);
367 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
368 		(*ifp->if_start)(ifp);
369 	splx(s);
370 
371 	return (error);
372 
373 bad:
374 	if (m1)
375 		m_freem(m1);
376 	if (m)
377 		m_freem(m);
378 	return (error);
379 }
380 
381 /*
382  * Defragmenter. Returns mbuf if last packet found, else
383  * NULL. frees imcoming mbuf as necessary.
384  */
385 
386 __inline struct mbuf *
387 arc_defrag(ifp, m)
388 	struct ifnet *ifp;
389 	struct mbuf *m;
390 {
391 	struct arc_header *ah, *ah1;
392 	struct arccom *ac;
393 	struct ac_frag *af;
394 	struct mbuf *m1;
395 	char *s;
396 	int newflen;
397 	u_char src,dst,typ;
398 
399 	ac = (struct arccom *)ifp;
400 
401 	if (m->m_len < ARC_HDRNEWLEN) {
402 		m = m_pullup(m, ARC_HDRNEWLEN);
403 		if (m == NULL) {
404 			++ifp->if_ierrors;
405 			return NULL;
406 		}
407 	}
408 
409 	ah = mtod(m, struct arc_header *);
410 	typ = ah->arc_type;
411 
412 	if (!arc_isphds(typ))
413 		return m;
414 
415 	src = ah->arc_shost;
416 	dst = ah->arc_dhost;
417 
418 	if (ah->arc_flag == 0xff) {
419 		m_adj(m, 4);
420 
421 		if (m->m_len < ARC_HDRNEWLEN) {
422 			m = m_pullup(m, ARC_HDRNEWLEN);
423 			if (m == NULL) {
424 				++ifp->if_ierrors;
425 				return NULL;
426 			}
427 		}
428 
429 		ah = mtod(m, struct arc_header *);
430 	}
431 
432 	af = &ac->ac_fragtab[src];
433 	m1 = af->af_packet;
434 	s = "debug code error";
435 
436 	if (ah->arc_flag & 1) {
437 		/*
438 		 * first fragment. We always initialize, which is
439 		 * about the right thing to do, as we only want to
440 		 * accept one fragmented packet per src at a time.
441 		 */
442 		if (m1 != NULL)
443 			m_freem(m1);
444 
445 		af->af_packet = m;
446 		m1 = m;
447 		af->af_maxflag = ah->arc_flag;
448 		af->af_lastseen = 0;
449 		af->af_seqid = ah->arc_seqid;
450 
451 		return NULL;
452 		/* notreached */
453 	} else {
454 		/* check for unfragmented packet */
455 		if (ah->arc_flag == 0)
456 			return m;
457 
458 		/* do we have a first packet from that src? */
459 		if (m1 == NULL) {
460 			s = "no first frag";
461 			goto outofseq;
462 		}
463 
464 		ah1 = mtod(m1, struct arc_header *);
465 
466 		if (ah->arc_seqid != ah1->arc_seqid) {
467 			s = "seqid differs";
468 			goto outofseq;
469 		}
470 
471 		if (typ != ah1->arc_type) {
472 			s = "type differs";
473 			goto outofseq;
474 		}
475 
476 		if (dst != ah1->arc_dhost) {
477 			s = "dest host differs";
478 			goto outofseq;
479 		}
480 
481 		/* typ, seqid and dst are ok here. */
482 
483 		if (ah->arc_flag == af->af_lastseen) {
484 			m_freem(m);
485 			return NULL;
486 		}
487 
488 		if (ah->arc_flag == af->af_lastseen + 2) {
489 			/* ok, this is next fragment */
490 			af->af_lastseen = ah->arc_flag;
491 			m_adj(m,ARC_HDRNEWLEN);
492 
493 			/*
494 			 * m_cat might free the first mbuf (with pkthdr)
495 			 * in 2nd chain; therefore:
496 			 */
497 
498 			newflen = m->m_pkthdr.len;
499 
500 			m_cat(m1,m);
501 
502 			m1->m_pkthdr.len += newflen;
503 
504 			/* is it the last one? */
505 			if (af->af_lastseen > af->af_maxflag) {
506 				af->af_packet = NULL;
507 				return(m1);
508 			} else
509 				return NULL;
510 		}
511 		s = "other reason";
512 		/* if all else fails, it is out of sequence, too */
513 	}
514 outofseq:
515 	if (m1) {
516 		m_freem(m1);
517 		af->af_packet = NULL;
518 	}
519 
520 	if (m)
521 		m_freem(m);
522 
523 	log(LOG_INFO,"%s: got out of seq. packet: %s\n",
524 	    ifp->if_xname, s);
525 
526 	return NULL;
527 }
528 
529 /*
530  * return 1 if Packet Header Definition Standard, else 0.
531  * For now: old IP, old ARP aren't obviously. Lacking correct information,
532  * we guess that besides new IP and new ARP also IPX and APPLETALK are PHDS.
533  * (Apple and Novell corporations were involved, among others, in PHDS work).
534  * Easiest is to assume that everybody else uses that, too.
535  */
536 int
537 arc_isphds(type)
538 	u_int8_t type;
539 {
540 	return (type != ARCTYPE_IP_OLD &&
541 		type != ARCTYPE_ARP_OLD &&
542 		type != ARCTYPE_DIAGNOSE);
543 }
544 
545 /*
546  * Process a received Arcnet packet;
547  * the packet is in the mbuf chain m with
548  * the ARCnet header.
549  */
550 static void
551 arc_input(ifp, m)
552 	struct ifnet *ifp;
553 	struct mbuf *m;
554 {
555 	struct arc_header *ah;
556 	struct ifqueue *inq;
557 	u_int8_t atype;
558 	int s;
559 	struct arphdr *arph;
560 
561 	if ((ifp->if_flags & IFF_UP) == 0) {
562 		m_freem(m);
563 		return;
564 	}
565 
566 	/* possibly defragment: */
567 	m = arc_defrag(ifp, m);
568 	if (m == NULL)
569 		return;
570 
571 	ah = mtod(m, struct arc_header *);
572 
573 	ifp->if_ibytes += m->m_pkthdr.len;
574 
575 	if (arcbroadcastaddr == ah->arc_dhost) {
576 		m->m_flags |= M_BCAST|M_MCAST;
577 		ifp->if_imcasts++;
578 	}
579 
580 	atype = ah->arc_type;
581 	switch (atype) {
582 #ifdef INET
583 	case ARCTYPE_IP:
584 		m_adj(m, ARC_HDRNEWLEN);
585 		schednetisr(NETISR_IP);
586 		inq = &ipintrq;
587 		break;
588 
589 	case ARCTYPE_IP_OLD:
590 		m_adj(m, ARC_HDRLEN);
591 		schednetisr(NETISR_IP);
592 		inq = &ipintrq;
593 		break;
594 
595 	case ARCTYPE_ARP:
596 		m_adj(m, ARC_HDRNEWLEN);
597 		schednetisr(NETISR_ARP);
598 		inq = &arpintrq;
599 #ifdef ARCNET_ALLOW_BROKEN_ARP
600 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
601 #endif
602 		break;
603 
604 	case ARCTYPE_ARP_OLD:
605 		m_adj(m, ARC_HDRLEN);
606 		schednetisr(NETISR_ARP);
607 		inq = &arpintrq;
608 		arph = mtod(m, struct arphdr *);
609 #ifdef ARCNET_ALLOW_BROKEN_ARP
610 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
611 #endif
612 		break;
613 #endif
614 #ifdef INET6
615 	case ARCTYPE_INET6:
616 		m_adj(m, ARC_HDRNEWLEN);
617 		schednetisr(NETISR_IPV6);
618 		inq = &ip6intrq;
619 		break;
620 #endif
621 	default:
622 		m_freem(m);
623 		return;
624 	}
625 
626 	s = splnet();
627 	if (IF_QFULL(inq)) {
628 		IF_DROP(inq);
629 		m_freem(m);
630 	} else
631 		IF_ENQUEUE(inq, m);
632 	splx(s);
633 }
634 
635 /*
636  * Convert Arcnet address to printable (loggable) representation.
637  */
638 static char digits[] = "0123456789abcdef";
639 char *
640 arc_sprintf(ap)
641 	u_int8_t *ap;
642 {
643 	static char arcbuf[3];
644 	char *cp = arcbuf;
645 
646 	*cp++ = digits[*ap >> 4];
647 	*cp++ = digits[*ap++ & 0xf];
648 	*cp   = 0;
649 	return (arcbuf);
650 }
651 
652 /*
653  * Register (new) link level address.
654  */
655 void
656 arc_storelladdr(ifp, lla)
657 	struct ifnet *ifp;
658 	u_int8_t lla;
659 {
660 
661 	*(LLADDR(ifp->if_sadl)) = lla;
662 	ifp->if_mtu = ARC_PHDS_MAXMTU;
663 }
664 
665 /*
666  * Perform common duties while attaching to interface list
667  */
668 void
669 arc_ifattach(ifp, lla)
670 	struct ifnet *ifp;
671 	u_int8_t lla;
672 {
673 	struct arccom *ac;
674 
675 	ifp->if_type = IFT_ARCNET;
676 	ifp->if_addrlen = 1;
677 	ifp->if_hdrlen = ARC_HDRLEN;
678 	ifp->if_dlt = DLT_ARCNET;
679 	if (ifp->if_flags & IFF_BROADCAST)
680 		ifp->if_flags |= IFF_MULTICAST|IFF_ALLMULTI;
681 	if (ifp->if_flags & IFF_LINK0 && arc_ipmtu > ARC_PHDS_MAXMTU)
682 		log(LOG_ERR,
683 		    "%s: arc_ipmtu is %d, but must not exceed %d",
684 		    ifp->if_xname, arc_ipmtu, ARC_PHDS_MAXMTU);
685 
686 	ifp->if_output = arc_output;
687 	ifp->if_input = arc_input;
688 	ac = (struct arccom *)ifp;
689 	ac->ac_seqid = (time.tv_sec) & 0xFFFF; /* try to make seqid unique */
690 	if (lla == 0) {
691 		/* XXX this message isn't entirely clear, to me -- cgd */
692 		log(LOG_ERR,"%s: link address 0 reserved for broadcasts.  Please change it and ifconfig %s down up\n",
693 		   ifp->if_xname, ifp->if_xname);
694 	}
695 	if_attach(ifp);
696 	if_alloc_sadl(ifp);
697 	arc_storelladdr(ifp, lla);
698 
699 	ifp->if_broadcastaddr = &arcbroadcastaddr;
700 
701 #if NBPFILTER > 0
702 	bpfattach(ifp, DLT_ARCNET, ARC_HDRLEN);
703 #endif
704 }
705