Home | History | Annotate | Line # | Download | only in net
if_arcsubr.c revision 1.13
      1 /*	$NetBSD: if_arcsubr.c,v 1.13 1997/03/16 23:27:07 is 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/param.h>
     42 #include <sys/systm.h>
     43 #include <sys/kernel.h>
     44 #include <sys/malloc.h>
     45 #include <sys/mbuf.h>
     46 #include <sys/protosw.h>
     47 #include <sys/socket.h>
     48 #include <sys/ioctl.h>
     49 #include <sys/errno.h>
     50 #include <sys/syslog.h>
     51 
     52 #include <machine/cpu.h>
     53 
     54 #include <net/if.h>
     55 #include <net/netisr.h>
     56 #include <net/route.h>
     57 #include <net/if_dl.h>
     58 #include <net/if_types.h>
     59 #include <net/if_arc.h>
     60 #include <net/if_arp.h>
     61 #include <net/if_ether.h>
     62 
     63 #ifdef INET
     64 #include <netinet/in.h>
     65 #include <netinet/in_var.h>
     66 #endif
     67 
     68 #define ARCNET_ALLOW_BROKEN_ARP
     69 
     70 #ifndef	ARC_PHDSMTU
     71 #define	ARC_PHDSMTU	1500
     72 #endif
     73 
     74 static struct mbuf *arc_defrag __P((struct ifnet *, struct mbuf *));
     75 
     76 /*
     77  * RC1201 requires us to have this configurable. We have it only per
     78  * machine at the moment... there is no generic "set mtu" ioctl, AFAICS.
     79  * Anyway, it is possible to binpatch this or set it per kernel config
     80  * option.
     81  */
     82 #if ARC_PHDSMTU > 60480
     83 ERROR: The arc_phdsmtu is ARC_PHDSMTU, but must not exceed 60480.
     84 #endif
     85 u_int16_t arc_phdsmtu = ARC_PHDSMTU;
     86 u_int8_t  arcbroadcastaddr = 0;
     87 
     88 #define senderr(e) { error = (e); goto bad;}
     89 #define SIN(s) ((struct sockaddr_in *)s)
     90 
     91 /*
     92  * ARCnet output routine.
     93  * Encapsulate a packet of type family for the local net.
     94  * Assumes that ifp is actually pointer to arccom structure.
     95  */
     96 int
     97 arc_output(ifp, m0, dst, rt0)
     98 	register struct ifnet *ifp;
     99 	struct mbuf *m0;
    100 	struct sockaddr *dst;
    101 	struct rtentry *rt0;
    102 {
    103 	struct mbuf		*m, *m1, *mcopy;
    104 	struct rtentry		*rt;
    105 	struct arccom		*ac;
    106 	register struct arc_header *ah;
    107 	int			s, error, newencoding;
    108 	u_int8_t		atype, adst, myself;
    109 	int			tfrags, sflag, fsflag, rsflag;
    110 
    111 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
    112 		return(ENETDOWN); /* m, m1 aren't initialized yet */
    113 
    114 	error = newencoding = 0;
    115 	ac = (struct arccom *)ifp;
    116 	m = m0;
    117 	mcopy = m1 = NULL;
    118 
    119 	myself = *LLADDR(ifp->if_sadl);
    120 
    121 	ifp->if_lastchange = time;
    122 	if ((rt = rt0)) {
    123 		if ((rt->rt_flags & RTF_UP) == 0) {
    124 			if ((rt0 = rt = rtalloc1(dst, 1)))
    125 				rt->rt_refcnt--;
    126 			else
    127 				senderr(EHOSTUNREACH);
    128 		}
    129 		if (rt->rt_flags & RTF_GATEWAY) {
    130 			if (rt->rt_gwroute == 0)
    131 				goto lookup;
    132 			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
    133 				rtfree(rt); rt = rt0;
    134 			lookup: rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
    135 				if ((rt = rt->rt_gwroute) == 0)
    136 					senderr(EHOSTUNREACH);
    137 			}
    138 		}
    139 		if (rt->rt_flags & RTF_REJECT)
    140 			if (rt->rt_rmx.rmx_expire == 0 ||
    141 			    time.tv_sec < rt->rt_rmx.rmx_expire)
    142 				senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
    143 	}
    144 
    145 	switch (dst->sa_family) {
    146 #ifdef INET
    147 	case AF_INET:
    148 
    149 		/*
    150 		 * For now, use the simple IP addr -> ARCnet addr mapping
    151 		 */
    152 		if (m->m_flags & (M_BCAST|M_MCAST))
    153 			adst = arcbroadcastaddr; /* ARCnet broadcast address */
    154 		else if (ifp->if_flags & IFF_NOARP)
    155 			adst = ntohl(SIN(dst)->sin_addr.s_addr) & 0xFF;
    156 		else if (!arpresolve(ifp, rt, m, dst, &adst))
    157 			return 0;	/* not resolved yet */
    158 
    159 		/* If broadcasting on a simplex interface, loopback a copy */
    160 		if ((m->m_flags & (M_BCAST|M_MCAST)) &&
    161 		    (ifp->if_flags & IFF_SIMPLEX))
    162 			mcopy = m_copy(m, 0, (int)M_COPYALL);
    163 		if (ifp->if_flags & IFF_LINK0) {
    164 			atype = ARCTYPE_IP;
    165 			newencoding = 1;
    166 		} else {
    167 			atype = ARCTYPE_IP_OLD;
    168 			newencoding = 0;
    169 		}
    170 		break;
    171 
    172 	case AF_ARP:
    173 		ah = mtod(m, struct arphdr *);
    174 		if (m->m_flags & M_BCAST)
    175 			adst = arcbroadcastaddr;
    176 		else
    177 			adst = *ar_tha(ah);
    178 
    179 		switch(ntohs(ah->ar_op)) {
    180 		case ARPOP_REVREQUEST:
    181 		case ARPOP_REVREPLY:
    182 			if (!(ifp->if_flags & IFF_LINK0)) {
    183 				printf("%s: can't handle af%d\n",
    184 				    ifp->if_xname, dst->sa_family);
    185 				senderr(EAFNOSUPPORT);
    186 			}
    187 
    188 			atype = htons(ARCTYPE_REVARP);
    189 			newencoding = 1;
    190 			break;
    191 
    192 		case ARPOP_REQUEST:
    193 		case ARPOP_REPLY:
    194 		default:
    195 			if (ifp->if_flags & IFF_LINK0) {
    196 				atype = htons(ARCTYPE_ARP);
    197 				newencoding = 1;
    198 			} else {
    199 				atype = htons(ARCTYPE_ARP_OLD);
    200 				newencoding = 0;
    201 			}
    202 		}
    203 #ifdef ARCNET_ALLOW_BROKEN_ARP
    204 		/*
    205 		 * XXX It's not clear per RFC826 if this is needed, but
    206 		 * "assigned numbers" say this is wrong.
    207 		 * However, e.g., AmiTCP 3.0Beta used it... we make this
    208 		 * switchable for emergency cases. Not perfect, but...
    209 		 */
    210 		if (ifp->if_flags & IFF_LINK2) {
    211 			ah->ar_pro = atype;
    212 		}
    213 #endif
    214 		break;
    215 #endif
    216 
    217 	case AF_UNSPEC:
    218 		ah = (struct arc_header *)dst->sa_data;
    219  		adst = ah->arc_dhost;
    220 		atype = ah->arc_type;
    221 		break;
    222 
    223 	default:
    224 		printf("%s: can't handle af%d\n", ifp->if_xname,
    225 		    dst->sa_family);
    226 		senderr(EAFNOSUPPORT);
    227 	}
    228 
    229 	if (mcopy)
    230 		(void) looutput(ifp, mcopy, dst, rt);
    231 
    232 	/*
    233 	 * Add local net header.  If no space in first mbuf,
    234 	 * allocate another.
    235 	 *
    236 	 * For ARCnet, this is just symbolic. The header changes
    237 	 * form and position on its way into the hardware and out of
    238 	 * the wire.  At this point, it contains source, destination and
    239 	 * packet type.
    240 	 */
    241 	if (newencoding) {
    242 		++ac->ac_seqid; /* make the seqid unique */
    243 
    244 		tfrags = (m->m_pkthdr.len + 503) / 504;
    245 		fsflag = 2 * tfrags - 3;
    246 		sflag = 0;
    247 		rsflag = fsflag;
    248 
    249 		while (sflag < fsflag) {
    250 			/* we CAN'T have short packets here */
    251 			m1 = m_split(m, 504, M_DONTWAIT);
    252 			if (m1 == 0)
    253 				senderr(ENOBUFS);
    254 
    255 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
    256 			if (m == 0)
    257 				senderr(ENOBUFS);
    258 			ah = mtod(m, struct arc_header *);
    259 			ah->arc_type = atype;
    260 			ah->arc_dhost = adst;
    261 			ah->arc_shost = myself;
    262 			ah->arc_flag = rsflag;
    263 			ah->arc_seqid = ac->ac_seqid;
    264 
    265 			s = splimp();
    266 			/*
    267 			 * Queue message on interface, and start output if
    268 			 * interface not yet active.
    269 			 */
    270 			if (IF_QFULL(&ifp->if_snd)) {
    271 				IF_DROP(&ifp->if_snd);
    272 				splx(s);
    273 				senderr(ENOBUFS);
    274 			}
    275 			ifp->if_obytes += m->m_pkthdr.len;
    276 			IF_ENQUEUE(&ifp->if_snd, m);
    277 			if ((ifp->if_flags & IFF_OACTIVE) == 0)
    278 				(*ifp->if_start)(ifp);
    279 			splx(s);
    280 
    281 			m = m1;
    282 			sflag += 2;
    283 			rsflag = sflag;
    284 		}
    285 		m1 = NULL;
    286 
    287 		M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
    288 		if (m == 0)
    289 			senderr(ENOBUFS);
    290 		ah = mtod(m, struct arc_header *);
    291 		ah->arc_type = atype;
    292 		ah->arc_flag = sflag;
    293 		ah->arc_seqid = ac->ac_seqid;
    294 
    295 		/* here we can have small, especially forbidden packets */
    296 
    297 		if ((m->m_pkthdr.len >= ARC_MIN_FORBID_LEN + 2) &&
    298 		    (m->m_pkthdr.len <= ARC_MAX_FORBID_LEN + 2)) {
    299 			M_PREPEND(m, 4, M_DONTWAIT);
    300 			if (m == 0)
    301 				senderr(ENOBUFS);
    302 			m = m_pullup(m, ARC_HDRNEWLEN);
    303 			if (m == 0)
    304 				senderr(ENOBUFS);
    305 			ah = mtod(m, struct arc_header *);
    306 			ah->arc_type = atype;
    307 			ah->arc_flag = 0xFF;
    308 			ah->arc_seqid = 0xFFFF;
    309 		}
    310 
    311 		ah->arc_dhost = adst;
    312 		ah->arc_shost = myself;
    313 	} else {
    314 		M_PREPEND(m, ARC_HDRLEN, M_DONTWAIT);
    315 		if (m == 0)
    316 			senderr(ENOBUFS);
    317 		ah = mtod(m, struct arc_header *);
    318 		ah->arc_type = atype;
    319 		ah->arc_dhost = adst;
    320 		ah->arc_shost = myself;
    321 	}
    322 
    323 	s = splimp();
    324 	/*
    325 	 * Queue message on interface, and start output if interface
    326 	 * not yet active.
    327 	 */
    328 	if (IF_QFULL(&ifp->if_snd)) {
    329 		IF_DROP(&ifp->if_snd);
    330 		splx(s);
    331 		senderr(ENOBUFS);
    332 	}
    333 	ifp->if_obytes += m->m_pkthdr.len;
    334 	IF_ENQUEUE(&ifp->if_snd, m);
    335 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
    336 		(*ifp->if_start)(ifp);
    337 	splx(s);
    338 
    339 	return (error);
    340 
    341 bad:
    342 	if (m1)
    343 		m_freem(m1);
    344 	if (m)
    345 		m_freem(m);
    346 	return (error);
    347 }
    348 
    349 /*
    350  * Defragmenter. Returns mbuf if last packet found, else
    351  * NULL. frees imcoming mbuf as necessary.
    352  */
    353 
    354 __inline struct mbuf *
    355 arc_defrag(ifp, m)
    356 	struct ifnet *ifp;
    357 	struct mbuf *m;
    358 {
    359 	struct arc_header *ah, *ah1;
    360 	struct arccom *ac;
    361 	struct ac_frag *af;
    362 	struct mbuf *m1;
    363 	char *s;
    364 	int newflen;
    365 	u_char src,dst,typ;
    366 
    367 	ac = (struct arccom *)ifp;
    368 
    369 	m = m_pullup(m, ARC_HDRNEWLEN);
    370 	if (m == NULL) {
    371 		++ifp->if_ierrors;
    372 		return NULL;
    373 	}
    374 
    375 	ah = mtod(m, struct arc_header *);
    376 	typ = ah->arc_type;
    377 
    378 	if (!arc_isphds(typ))
    379 		return m;
    380 
    381 	src = ah->arc_shost;
    382 	dst = ah->arc_dhost;
    383 
    384 	if (ah->arc_flag == 0xff) {
    385 		m_adj(m, 4);
    386 
    387 		m = m_pullup(m, ARC_HDRNEWLEN);
    388 		if (m == NULL) {
    389 			++ifp->if_ierrors;
    390 			return NULL;
    391 		}
    392 
    393 		ah = mtod(m, struct arc_header *);
    394 		ah->arc_shost = src;
    395 		ah->arc_dhost = dst;
    396 		ah->arc_type = typ;
    397 	}
    398 
    399 	af = &ac->ac_fragtab[src];
    400 	m1 = af->af_packet;
    401 	s = "debug code error";
    402 
    403 	if (ah->arc_flag & 1) {
    404 		/*
    405 		 * first fragment. We always initialize, which is
    406 		 * about the right thing to do, as we only want to
    407 		 * accept one fragmented packet per src at a time.
    408 		 */
    409 		if (m1 != NULL)
    410 			m_freem(m1);
    411 
    412 		af->af_packet = m;
    413 		m1 = m;
    414 		af->af_maxflag = ah->arc_flag;
    415 		af->af_lastseen = 0;
    416 		af->af_seqid = ah->arc_seqid;
    417 
    418 		return NULL;
    419 		/* notreached */
    420 	} else {
    421 		/* check for unfragmented packet */
    422 		if (ah->arc_flag == 0)
    423 			return m;
    424 
    425 		/* do we have a first packet from that src? */
    426 		if (m1 == NULL) {
    427 			s = "no first frag";
    428 			goto outofseq;
    429 		}
    430 
    431 		ah1 = mtod(m1, struct arc_header *);
    432 
    433 		if (ah->arc_seqid != ah1->arc_seqid) {
    434 			s = "seqid differs";
    435 			goto outofseq;
    436 		}
    437 
    438 		if (ah->arc_type != ah1->arc_type) {
    439 			s = "type differs";
    440 			goto outofseq;
    441 		}
    442 
    443 		if (ah->arc_dhost != ah1->arc_dhost) {
    444 			s = "dest host differs";
    445 			goto outofseq;
    446 		}
    447 
    448 		/* typ, seqid and dst are ok here. */
    449 
    450 		if (ah->arc_flag == af->af_lastseen) {
    451 			m_freem(m);
    452 			return NULL;
    453 		}
    454 
    455 		if (ah->arc_flag == af->af_lastseen + 2) {
    456 			/* ok, this is next fragment */
    457 			af->af_lastseen = ah->arc_flag;
    458 			m_adj(m,ARC_HDRNEWLEN);
    459 
    460 			/*
    461 			 * m_cat might free the first mbuf (with pkthdr)
    462 			 * in 2nd chain; therefore:
    463 			 */
    464 
    465 			newflen = m->m_pkthdr.len;
    466 
    467 			m_cat(m1,m);
    468 
    469 			m1->m_pkthdr.len += newflen;
    470 
    471 			/* is it the last one? */
    472 			if (af->af_lastseen > af->af_maxflag) {
    473 				af->af_packet = NULL;
    474 				return(m1);
    475 			} else
    476 				return NULL;
    477 		}
    478 		s = "other reason";
    479 		/* if all else fails, it is out of sequence, too */
    480 	}
    481 outofseq:
    482 	if (m1) {
    483 		m_freem(m1);
    484 		af->af_packet = NULL;
    485 	}
    486 
    487 	if (m)
    488 		m_freem(m);
    489 
    490 	log(LOG_INFO,"%s: got out of seq. packet: %s\n",
    491 	    ifp->if_xname, s);
    492 
    493 	return NULL;
    494 }
    495 
    496 /*
    497  * return 1 if Packet Header Definition Standard, else 0.
    498  * For now: old IP, old ARP aren't obviously. Lacking correct information,
    499  * we guess that besides new IP and new ARP also IPX and APPLETALK are PHDS.
    500  * (Apple and Novell corporations were involved, among others, in PHDS work).
    501  * Easiest is to assume that everybody else uses that, too.
    502  */
    503 int
    504 arc_isphds(type)
    505 	u_int8_t type;
    506 {
    507 	return ((type != ARCTYPE_IP_OLD &&
    508 		 type != ARCTYPE_ARP_OLD));
    509 }
    510 
    511 /*
    512  * Process a received Arcnet packet;
    513  * the packet is in the mbuf chain m with
    514  * the ARCnet header.
    515  */
    516 void
    517 arc_input(ifp, m)
    518 	struct ifnet *ifp;
    519 	struct mbuf *m;
    520 {
    521 	register struct arc_header *ah;
    522 	register struct ifqueue *inq;
    523 	u_int8_t atype;
    524 	int s;
    525 
    526 	if ((ifp->if_flags & IFF_UP) == 0) {
    527 		m_freem(m);
    528 		return;
    529 	}
    530 
    531 	/* possibly defragment: */
    532 	m = arc_defrag(ifp, m);
    533 	if (m == NULL)
    534 		return;
    535 
    536 	ah = mtod(m, struct arc_header *);
    537 
    538 	ifp->if_lastchange = time;
    539 	ifp->if_ibytes += m->m_pkthdr.len;
    540 
    541 	if (arcbroadcastaddr == ah->arc_dhost) {
    542 		m->m_flags |= M_BCAST|M_MCAST;
    543 		ifp->if_imcasts++;
    544 	}
    545 
    546 	atype = ah->arc_type;
    547 	switch (atype) {
    548 #ifdef INET
    549 	case ARCTYPE_IP:
    550 		m_adj(m, ARC_HDRNEWLEN);
    551 		schednetisr(NETISR_IP);
    552 		inq = &ipintrq;
    553 		break;
    554 
    555 	case ARCTYPE_IP_OLD:
    556 		m_adj(m, ARC_HDRLEN);
    557 		schednetisr(NETISR_IP);
    558 		inq = &ipintrq;
    559 		break;
    560 
    561 	case ARCTYPE_ARP:
    562 		m_adj(m, ARC_HDRNEWLEN);
    563 		schednetisr(NETISR_ARP);
    564 		inq = &arpintrq;
    565 #ifdef ARCNET_ALLOW_BROKEN_ARP
    566 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_ARP);
    567 #endif
    568 		break;
    569 
    570 	case ARCTYPE_ARP_OLD:
    571 		m_adj(m, ARC_HDRLEN);
    572 		schednetisr(NETISR_ARP);
    573 		inq = &arpintrq;
    574 #ifdef ARCNET_ALLOW_BROKEN_ARP
    575 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_ARP);
    576 #endif
    577 		break;
    578 #endif
    579 	default:
    580 		m_freem(m);
    581 		return;
    582 	}
    583 
    584 	s = splimp();
    585 	if (IF_QFULL(inq)) {
    586 		IF_DROP(inq);
    587 		m_freem(m);
    588 	} else
    589 		IF_ENQUEUE(inq, m);
    590 	splx(s);
    591 }
    592 
    593 /*
    594  * Convert Arcnet address to printable (loggable) representation.
    595  */
    596 static char digits[] = "0123456789abcdef";
    597 char *
    598 arc_sprintf(ap)
    599 	register u_int8_t *ap;
    600 {
    601 	static char arcbuf[3];
    602 	register char *cp = arcbuf;
    603 
    604 	*cp++ = digits[*ap >> 4];
    605 	*cp++ = digits[*ap++ & 0xf];
    606 	*cp   = 0;
    607 	return (arcbuf);
    608 }
    609 
    610 /*
    611  * Perform common duties while attaching to interface list
    612  */
    613 void
    614 arc_ifattach(ifp, lla)
    615 	register struct ifnet *ifp;
    616 	u_int8_t lla;
    617 {
    618 	register struct ifaddr *ifa;
    619 	register struct sockaddr_dl *sdl;
    620 	register struct arccom *ac;
    621 
    622 	ifp->if_type = IFT_ARCNET;
    623 	ifp->if_addrlen = 1;
    624 	ifp->if_hdrlen = ARC_HDRLEN;
    625 	if (ifp->if_flags & IFF_BROADCAST)
    626 		ifp->if_flags |= IFF_MULTICAST|IFF_ALLMULTI;
    627 	if (ifp->if_flags & IFF_LINK0 && arc_phdsmtu > 60480)
    628 		log(LOG_ERR,
    629 		    "%s: arc_phdsmtu is %d, but must not exceed 60480",
    630 		    ifp->if_xname, arc_phdsmtu);
    631 
    632 	ifp->if_mtu = (ifp->if_flags & IFF_LINK0 ? arc_phdsmtu : ARCMTU);
    633 	ac = (struct arccom *)ifp;
    634 	ac->ac_seqid = (time.tv_sec) & 0xFFFF; /* try to make seqid unique */
    635 	if (lla == 0) {
    636 		/* XXX this message isn't entirely clear, to me -- cgd */
    637 		log(LOG_ERR,"%s: link address 0 reserved for broadcasts.  Please change it and ifconfig %s down up\n",
    638 		   ifp->if_xname, ifp->if_xname);
    639 	}
    640 	if ((sdl = ifp->if_sadl) &&
    641 	   sdl->sdl_family == AF_LINK) {
    642 		sdl->sdl_type = IFT_ARCNET;
    643 		sdl->sdl_alen = ifp->if_addrlen;
    644 		bcopy((caddr_t)&lla, LLADDR(sdl), ifp->if_addrlen);
    645 	}
    646 }
    647