xref: /netbsd-src/sys/net/if_arcsubr.c (revision 001c68bd94f75ce9270b69227c4199fbf34ee396)
1 /*	$NetBSD: if_arcsubr.c,v 1.42 2003/05/02 03:15:23 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 
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: if_arcsubr.c,v 1.42 2003/05/02 03:15:23 itojun Exp $");
43 
44 #include "opt_inet.h"
45 
46 #include "bpfilter.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/malloc.h>
52 #include <sys/mbuf.h>
53 #include <sys/protosw.h>
54 #include <sys/socket.h>
55 #include <sys/ioctl.h>
56 #include <sys/errno.h>
57 #include <sys/syslog.h>
58 
59 #include <machine/cpu.h>
60 
61 #include <net/if.h>
62 #include <net/netisr.h>
63 #include <net/route.h>
64 #include <net/if_dl.h>
65 #include <net/if_types.h>
66 #include <net/if_arc.h>
67 #include <net/if_arp.h>
68 #include <net/if_ether.h>
69 
70 #if NBPFILTER > 0
71 #include <net/bpf.h>
72 #endif
73 
74 #ifdef INET
75 #include <netinet/in.h>
76 #include <netinet/in_var.h>
77 #include <netinet/if_inarp.h>
78 #endif
79 
80 #ifdef INET6
81 #ifndef INET
82 #include <netinet/in.h>
83 #endif
84 #include <netinet6/in6_var.h>
85 #include <netinet6/nd6.h>
86 #endif
87 
88 #define ARCNET_ALLOW_BROKEN_ARP
89 
90 #ifndef ARC_IPMTU
91 #define ARC_IPMTU	1500
92 #endif
93 
94 static struct mbuf *arc_defrag __P((struct ifnet *, struct mbuf *));
95 
96 /*
97  * RC1201 requires us to have this configurable. We have it only per
98  * machine at the moment... there is no generic "set mtu" ioctl, AFAICS.
99  * Anyway, it is possible to binpatch this or set it per kernel config
100  * option.
101  */
102 #if ARC_IPMTU > 60480
103 ERROR: The arc_ipmtu is ARC_IPMTU, but must not exceed 60480.
104 #endif
105 int arc_ipmtu = ARC_IPMTU;
106 u_int8_t  arcbroadcastaddr = 0;
107 
108 #define senderr(e) { error = (e); goto bad;}
109 #define SIN(s) ((struct sockaddr_in *)s)
110 
111 static	int arc_output __P((struct ifnet *, struct mbuf *,
112 	    struct sockaddr *, struct rtentry *));
113 static	void arc_input __P((struct ifnet *, struct mbuf *));
114 
115 /*
116  * ARCnet output routine.
117  * Encapsulate a packet of type family for the local net.
118  * Assumes that ifp is actually pointer to arccom structure.
119  */
120 static int
121 arc_output(ifp, m0, dst, rt0)
122 	struct ifnet *ifp;
123 	struct mbuf *m0;
124 	struct sockaddr *dst;
125 	struct rtentry *rt0;
126 {
127 	struct mbuf		*m, *m1, *mcopy;
128 	struct rtentry		*rt;
129 	struct arccom		*ac;
130 	struct arc_header	*ah;
131 	struct arphdr		*arph;
132 	int			s, error, newencoding, len;
133 	u_int8_t		atype, adst, myself;
134 	int			tfrags, sflag, fsflag, rsflag;
135 	ALTQ_DECL(struct altq_pktattr pktattr;)
136 
137 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
138 		return (ENETDOWN); /* m, m1 aren't initialized yet */
139 
140 	error = newencoding = 0;
141 	ac = (struct arccom *)ifp;
142 	m = m0;
143 	mcopy = m1 = NULL;
144 
145 	myself = *LLADDR(ifp->if_sadl);
146 
147 	if ((rt = rt0)) {
148 		if ((rt->rt_flags & RTF_UP) == 0) {
149 			if ((rt0 = rt = rtalloc1(dst, 1)))
150 				rt->rt_refcnt--;
151 			else
152 				senderr(EHOSTUNREACH);
153 		}
154 		if (rt->rt_flags & RTF_GATEWAY) {
155 			if (rt->rt_gwroute == 0)
156 				goto lookup;
157 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
158 				rtfree(rt); rt = rt0;
159 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
160 				if ((rt = rt->rt_gwroute) == 0)
161 					senderr(EHOSTUNREACH);
162 			}
163 		}
164 		if (rt->rt_flags & RTF_REJECT)
165 			if (rt->rt_rmx.rmx_expire == 0 ||
166 			    time.tv_sec < rt->rt_rmx.rmx_expire)
167 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
168 	}
169 
170 	/*
171 	 * if the queueing discipline needs packet classification,
172 	 * do it before prepending link headers.
173 	 */
174 	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family, &pktattr);
175 
176 	switch (dst->sa_family) {
177 #ifdef INET
178 	case AF_INET:
179 
180 		/*
181 		 * For now, use the simple IP addr -> ARCnet addr mapping
182 		 */
183 		if (m->m_flags & (M_BCAST|M_MCAST))
184 			adst = arcbroadcastaddr; /* ARCnet broadcast address */
185 		else if (ifp->if_flags & IFF_NOARP)
186 			adst = ntohl(SIN(dst)->sin_addr.s_addr) & 0xFF;
187 		else if (!arpresolve(ifp, rt, m, dst, &adst))
188 			return 0;	/* not resolved yet */
189 
190 		/* If broadcasting on a simplex interface, loopback a copy */
191 		if ((m->m_flags & (M_BCAST|M_MCAST)) &&
192 		    (ifp->if_flags & IFF_SIMPLEX))
193 			mcopy = m_copy(m, 0, (int)M_COPYALL);
194 		if (ifp->if_flags & IFF_LINK0) {
195 			atype = ARCTYPE_IP;
196 			newencoding = 1;
197 		} else {
198 			atype = ARCTYPE_IP_OLD;
199 			newencoding = 0;
200 		}
201 		break;
202 
203 	case AF_ARP:
204 		arph = mtod(m, struct arphdr *);
205 		if (m->m_flags & M_BCAST)
206 			adst = arcbroadcastaddr;
207 		else
208 			adst = *ar_tha(arph);
209 
210 		arph->ar_hrd = htons(ARPHRD_ARCNET);
211 
212 		switch (ntohs(arph->ar_op)) {
213 		case ARPOP_REVREQUEST:
214 		case ARPOP_REVREPLY:
215 			if (!(ifp->if_flags & IFF_LINK0)) {
216 				printf("%s: can't handle af%d\n",
217 				    ifp->if_xname, dst->sa_family);
218 				senderr(EAFNOSUPPORT);
219 			}
220 
221 			atype = htons(ARCTYPE_REVARP);
222 			newencoding = 1;
223 			break;
224 
225 		case ARPOP_REQUEST:
226 		case ARPOP_REPLY:
227 		default:
228 			if (ifp->if_flags & IFF_LINK0) {
229 				atype = htons(ARCTYPE_ARP);
230 				newencoding = 1;
231 			} else {
232 				atype = htons(ARCTYPE_ARP_OLD);
233 				newencoding = 0;
234 			}
235 		}
236 #ifdef ARCNET_ALLOW_BROKEN_ARP
237 		/*
238 		 * XXX It's not clear per RFC826 if this is needed, but
239 		 * "assigned numbers" say this is wrong.
240 		 * However, e.g., AmiTCP 3.0Beta used it... we make this
241 		 * switchable for emergency cases. Not perfect, but...
242 		 */
243 		if (ifp->if_flags & IFF_LINK2)
244 			arph->ar_pro = atype - 1;
245 #endif
246 		break;
247 #endif
248 #ifdef INET6
249 	case AF_INET6:
250 		if (!nd6_storelladdr(ifp, rt, m, dst, (u_char *)&adst))
251 			return (0); /* it must be impossible, but... */
252 		atype = htons(ARCTYPE_INET6);
253 		newencoding = 1;
254 		break;
255 #endif
256 
257 	case AF_UNSPEC:
258 		ah = (struct arc_header *)dst->sa_data;
259  		adst = ah->arc_dhost;
260 		atype = ah->arc_type;
261 		break;
262 
263 	default:
264 		printf("%s: can't handle af%d\n", ifp->if_xname,
265 		    dst->sa_family);
266 		senderr(EAFNOSUPPORT);
267 	}
268 
269 	if (mcopy)
270 		(void) looutput(ifp, mcopy, dst, rt);
271 
272 	/*
273 	 * Add local net header.  If no space in first mbuf,
274 	 * allocate another.
275 	 *
276 	 * For ARCnet, this is just symbolic. The header changes
277 	 * form and position on its way into the hardware and out of
278 	 * the wire.  At this point, it contains source, destination and
279 	 * packet type.
280 	 */
281 	if (newencoding) {
282 		++ac->ac_seqid; /* make the seqid unique */
283 
284 		tfrags = (m->m_pkthdr.len + 503) / 504;
285 		fsflag = 2 * tfrags - 3;
286 		sflag = 0;
287 		rsflag = fsflag;
288 
289 		while (sflag < fsflag) {
290 			/* we CAN'T have short packets here */
291 			m1 = m_split(m, 504, M_DONTWAIT);
292 			if (m1 == 0)
293 				senderr(ENOBUFS);
294 
295 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
296 			if (m == 0)
297 				senderr(ENOBUFS);
298 			ah = mtod(m, struct arc_header *);
299 			ah->arc_type = atype;
300 			ah->arc_dhost = adst;
301 			ah->arc_shost = myself;
302 			ah->arc_flag = rsflag;
303 			ah->arc_seqid = ac->ac_seqid;
304 
305 			len = m->m_pkthdr.len;
306 			s = splnet();
307 			/*
308 			 * Queue message on interface, and start output if
309 			 * interface not yet active.
310 			 */
311 			IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
312 			if (error) {
313 				/* mbuf is already freed */
314 				splx(s);
315 				return (error);
316 			}
317 			ifp->if_obytes += len;
318 			if ((ifp->if_flags & IFF_OACTIVE) == 0)
319 				(*ifp->if_start)(ifp);
320 			splx(s);
321 
322 			m = m1;
323 			sflag += 2;
324 			rsflag = sflag;
325 		}
326 		m1 = NULL;
327 
328 
329 		/* here we can have small, especially forbidden packets */
330 
331 		if ((m->m_pkthdr.len >=
332 		    ARC_MIN_FORBID_LEN - ARC_HDRNEWLEN + 2) &&
333 		    (m->m_pkthdr.len <=
334 		    ARC_MAX_FORBID_LEN - ARC_HDRNEWLEN + 2)) {
335 
336 			M_PREPEND(m, ARC_HDRNEWLEN_EXC, M_DONTWAIT);
337 			if (m == 0)
338 				senderr(ENOBUFS);
339 			ah = mtod(m, struct arc_header *);
340 			ah->arc_flag = 0xFF;
341 			ah->arc_seqid = 0xFFFF;
342 			ah->arc_type2 = atype;
343 			ah->arc_flag2 = sflag;
344 			ah->arc_seqid2 = ac->ac_seqid;
345 		} else {
346 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
347 			if (m == 0)
348 				senderr(ENOBUFS);
349 			ah = mtod(m, struct arc_header *);
350 			ah->arc_flag = sflag;
351 			ah->arc_seqid = ac->ac_seqid;
352 		}
353 
354 		ah->arc_dhost = adst;
355 		ah->arc_shost = myself;
356 		ah->arc_type = atype;
357 	} else {
358 		M_PREPEND(m, ARC_HDRLEN, M_DONTWAIT);
359 		if (m == 0)
360 			senderr(ENOBUFS);
361 		ah = mtod(m, struct arc_header *);
362 		ah->arc_type = atype;
363 		ah->arc_dhost = adst;
364 		ah->arc_shost = myself;
365 	}
366 
367 	len = m->m_pkthdr.len;
368 	s = splnet();
369 	/*
370 	 * Queue message on interface, and start output if interface
371 	 * not yet active.
372 	 */
373 	IFQ_ENQUEUE(&ifp->if_snd, m, &pktattr, error);
374 	if (error) {
375 		/* mbuf is already freed */
376 		splx(s);
377 		return (error);
378 	}
379 	ifp->if_obytes += len;
380 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
381 		(*ifp->if_start)(ifp);
382 	splx(s);
383 
384 	return (error);
385 
386 bad:
387 	if (m1)
388 		m_freem(m1);
389 	if (m)
390 		m_freem(m);
391 	return (error);
392 }
393 
394 /*
395  * Defragmenter. Returns mbuf if last packet found, else
396  * NULL. frees imcoming mbuf as necessary.
397  */
398 
399 __inline struct mbuf *
400 arc_defrag(ifp, m)
401 	struct ifnet *ifp;
402 	struct mbuf *m;
403 {
404 	struct arc_header *ah, *ah1;
405 	struct arccom *ac;
406 	struct ac_frag *af;
407 	struct mbuf *m1;
408 	char *s;
409 	int newflen;
410 	u_char src,dst,typ;
411 
412 	ac = (struct arccom *)ifp;
413 
414 	if (m->m_len < ARC_HDRNEWLEN) {
415 		m = m_pullup(m, ARC_HDRNEWLEN);
416 		if (m == NULL) {
417 			++ifp->if_ierrors;
418 			return NULL;
419 		}
420 	}
421 
422 	ah = mtod(m, struct arc_header *);
423 	typ = ah->arc_type;
424 
425 	if (!arc_isphds(typ))
426 		return m;
427 
428 	src = ah->arc_shost;
429 	dst = ah->arc_dhost;
430 
431 	if (ah->arc_flag == 0xff) {
432 		m_adj(m, 4);
433 
434 		if (m->m_len < ARC_HDRNEWLEN) {
435 			m = m_pullup(m, ARC_HDRNEWLEN);
436 			if (m == NULL) {
437 				++ifp->if_ierrors;
438 				return NULL;
439 			}
440 		}
441 
442 		ah = mtod(m, struct arc_header *);
443 	}
444 
445 	af = &ac->ac_fragtab[src];
446 	m1 = af->af_packet;
447 	s = "debug code error";
448 
449 	if (ah->arc_flag & 1) {
450 		/*
451 		 * first fragment. We always initialize, which is
452 		 * about the right thing to do, as we only want to
453 		 * accept one fragmented packet per src at a time.
454 		 */
455 		if (m1 != NULL)
456 			m_freem(m1);
457 
458 		af->af_packet = m;
459 		m1 = m;
460 		af->af_maxflag = ah->arc_flag;
461 		af->af_lastseen = 0;
462 		af->af_seqid = ah->arc_seqid;
463 
464 		return NULL;
465 		/* notreached */
466 	} else {
467 		/* check for unfragmented packet */
468 		if (ah->arc_flag == 0)
469 			return m;
470 
471 		/* do we have a first packet from that src? */
472 		if (m1 == NULL) {
473 			s = "no first frag";
474 			goto outofseq;
475 		}
476 
477 		ah1 = mtod(m1, struct arc_header *);
478 
479 		if (ah->arc_seqid != ah1->arc_seqid) {
480 			s = "seqid differs";
481 			goto outofseq;
482 		}
483 
484 		if (typ != ah1->arc_type) {
485 			s = "type differs";
486 			goto outofseq;
487 		}
488 
489 		if (dst != ah1->arc_dhost) {
490 			s = "dest host differs";
491 			goto outofseq;
492 		}
493 
494 		/* typ, seqid and dst are ok here. */
495 
496 		if (ah->arc_flag == af->af_lastseen) {
497 			m_freem(m);
498 			return NULL;
499 		}
500 
501 		if (ah->arc_flag == af->af_lastseen + 2) {
502 			/* ok, this is next fragment */
503 			af->af_lastseen = ah->arc_flag;
504 			m_adj(m,ARC_HDRNEWLEN);
505 
506 			/*
507 			 * m_cat might free the first mbuf (with pkthdr)
508 			 * in 2nd chain; therefore:
509 			 */
510 
511 			newflen = m->m_pkthdr.len;
512 
513 			m_cat(m1,m);
514 
515 			m1->m_pkthdr.len += newflen;
516 
517 			/* is it the last one? */
518 			if (af->af_lastseen > af->af_maxflag) {
519 				af->af_packet = NULL;
520 				return (m1);
521 			} else
522 				return NULL;
523 		}
524 		s = "other reason";
525 		/* if all else fails, it is out of sequence, too */
526 	}
527 outofseq:
528 	if (m1) {
529 		m_freem(m1);
530 		af->af_packet = NULL;
531 	}
532 
533 	if (m)
534 		m_freem(m);
535 
536 	log(LOG_INFO,"%s: got out of seq. packet: %s\n",
537 	    ifp->if_xname, s);
538 
539 	return NULL;
540 }
541 
542 /*
543  * return 1 if Packet Header Definition Standard, else 0.
544  * For now: old IP, old ARP aren't obviously. Lacking correct information,
545  * we guess that besides new IP and new ARP also IPX and APPLETALK are PHDS.
546  * (Apple and Novell corporations were involved, among others, in PHDS work).
547  * Easiest is to assume that everybody else uses that, too.
548  */
549 int
550 arc_isphds(type)
551 	u_int8_t type;
552 {
553 	return (type != ARCTYPE_IP_OLD &&
554 		type != ARCTYPE_ARP_OLD &&
555 		type != ARCTYPE_DIAGNOSE);
556 }
557 
558 /*
559  * Process a received Arcnet packet;
560  * the packet is in the mbuf chain m with
561  * the ARCnet header.
562  */
563 static void
564 arc_input(ifp, m)
565 	struct ifnet *ifp;
566 	struct mbuf *m;
567 {
568 	struct arc_header *ah;
569 	struct ifqueue *inq;
570 	u_int8_t atype;
571 	int s;
572 
573 	if ((ifp->if_flags & IFF_UP) == 0) {
574 		m_freem(m);
575 		return;
576 	}
577 
578 	/* possibly defragment: */
579 	m = arc_defrag(ifp, m);
580 	if (m == NULL)
581 		return;
582 
583 	ah = mtod(m, struct arc_header *);
584 
585 	ifp->if_ibytes += m->m_pkthdr.len;
586 
587 	if (arcbroadcastaddr == ah->arc_dhost) {
588 		m->m_flags |= M_BCAST|M_MCAST;
589 		ifp->if_imcasts++;
590 	}
591 
592 	atype = ah->arc_type;
593 	switch (atype) {
594 #ifdef INET
595 	case ARCTYPE_IP:
596 		m_adj(m, ARC_HDRNEWLEN);
597 		schednetisr(NETISR_IP);
598 		inq = &ipintrq;
599 		break;
600 
601 	case ARCTYPE_IP_OLD:
602 		m_adj(m, ARC_HDRLEN);
603 		schednetisr(NETISR_IP);
604 		inq = &ipintrq;
605 		break;
606 
607 	case ARCTYPE_ARP:
608 		m_adj(m, ARC_HDRNEWLEN);
609 		schednetisr(NETISR_ARP);
610 		inq = &arpintrq;
611 #ifdef ARCNET_ALLOW_BROKEN_ARP
612 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
613 #endif
614 		break;
615 
616 	case ARCTYPE_ARP_OLD:
617 		m_adj(m, ARC_HDRLEN);
618 		schednetisr(NETISR_ARP);
619 		inq = &arpintrq;
620 #ifdef ARCNET_ALLOW_BROKEN_ARP
621 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
622 #endif
623 		break;
624 #endif
625 #ifdef INET6
626 	case ARCTYPE_INET6:
627 		m_adj(m, ARC_HDRNEWLEN);
628 		schednetisr(NETISR_IPV6);
629 		inq = &ip6intrq;
630 		break;
631 #endif
632 	default:
633 		m_freem(m);
634 		return;
635 	}
636 
637 	s = splnet();
638 	if (IF_QFULL(inq)) {
639 		IF_DROP(inq);
640 		m_freem(m);
641 	} else
642 		IF_ENQUEUE(inq, m);
643 	splx(s);
644 }
645 
646 /*
647  * Convert Arcnet address to printable (loggable) representation.
648  */
649 static char digits[] = "0123456789abcdef";
650 char *
651 arc_sprintf(ap)
652 	u_int8_t *ap;
653 {
654 	static char arcbuf[3];
655 	char *cp = arcbuf;
656 
657 	*cp++ = digits[*ap >> 4];
658 	*cp++ = digits[*ap++ & 0xf];
659 	*cp   = 0;
660 	return (arcbuf);
661 }
662 
663 /*
664  * Register (new) link level address.
665  */
666 void
667 arc_storelladdr(ifp, lla)
668 	struct ifnet *ifp;
669 	u_int8_t lla;
670 {
671 
672 	*(LLADDR(ifp->if_sadl)) = lla;
673 	ifp->if_mtu = ARC_PHDS_MAXMTU;
674 }
675 
676 /*
677  * Perform common duties while attaching to interface list
678  */
679 void
680 arc_ifattach(ifp, lla)
681 	struct ifnet *ifp;
682 	u_int8_t lla;
683 {
684 	struct arccom *ac;
685 
686 	ifp->if_type = IFT_ARCNET;
687 	ifp->if_addrlen = 1;
688 	ifp->if_hdrlen = ARC_HDRLEN;
689 	ifp->if_dlt = DLT_ARCNET;
690 	if (ifp->if_flags & IFF_BROADCAST)
691 		ifp->if_flags |= IFF_MULTICAST|IFF_ALLMULTI;
692 	if (ifp->if_flags & IFF_LINK0 && arc_ipmtu > ARC_PHDS_MAXMTU)
693 		log(LOG_ERR,
694 		    "%s: arc_ipmtu is %d, but must not exceed %d",
695 		    ifp->if_xname, arc_ipmtu, ARC_PHDS_MAXMTU);
696 
697 	ifp->if_output = arc_output;
698 	ifp->if_input = arc_input;
699 	ac = (struct arccom *)ifp;
700 	ac->ac_seqid = (time.tv_sec) & 0xFFFF; /* try to make seqid unique */
701 	if (lla == 0) {
702 		/* XXX this message isn't entirely clear, to me -- cgd */
703 		log(LOG_ERR,"%s: link address 0 reserved for broadcasts.  Please change it and ifconfig %s down up\n",
704 		   ifp->if_xname, ifp->if_xname);
705 	}
706 	if_attach(ifp);
707 	if_alloc_sadl(ifp);
708 	arc_storelladdr(ifp, lla);
709 
710 	ifp->if_broadcastaddr = &arcbroadcastaddr;
711 
712 #if NBPFILTER > 0
713 	bpfattach(ifp, DLT_ARCNET, ARC_HDRLEN);
714 #endif
715 }
716