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if_arcsubr.c revision 1.34.2.1
      1 /*	$NetBSD: if_arcsubr.c,v 1.34.2.1 2001/06/21 20:07:58 nathanw 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 #ifdef OLDIP6OUTPUT
    241 		if (!nd6_resolve(ifp, rt, m, dst, (u_char *)&adst))
    242 			return(0);	/* if not yet resolves */
    243 #else
    244 		if (!nd6_storelladdr(ifp, rt, m, dst, (u_char *)&adst))
    245 			return(0); /* it must be impossible, but... */
    246 #endif /* OLDIP6OUTPUT */
    247 		atype = htons(ARCTYPE_INET6);
    248 		newencoding = 1;
    249 		break;
    250 #endif
    251 
    252 	case AF_UNSPEC:
    253 		ah = (struct arc_header *)dst->sa_data;
    254  		adst = ah->arc_dhost;
    255 		atype = ah->arc_type;
    256 		break;
    257 
    258 	default:
    259 		printf("%s: can't handle af%d\n", ifp->if_xname,
    260 		    dst->sa_family);
    261 		senderr(EAFNOSUPPORT);
    262 	}
    263 
    264 	if (mcopy)
    265 		(void) looutput(ifp, mcopy, dst, rt);
    266 
    267 	/*
    268 	 * Add local net header.  If no space in first mbuf,
    269 	 * allocate another.
    270 	 *
    271 	 * For ARCnet, this is just symbolic. The header changes
    272 	 * form and position on its way into the hardware and out of
    273 	 * the wire.  At this point, it contains source, destination and
    274 	 * packet type.
    275 	 */
    276 	if (newencoding) {
    277 		++ac->ac_seqid; /* make the seqid unique */
    278 
    279 		tfrags = (m->m_pkthdr.len + 503) / 504;
    280 		fsflag = 2 * tfrags - 3;
    281 		sflag = 0;
    282 		rsflag = fsflag;
    283 
    284 		while (sflag < fsflag) {
    285 			/* we CAN'T have short packets here */
    286 			m1 = m_split(m, 504, M_DONTWAIT);
    287 			if (m1 == 0)
    288 				senderr(ENOBUFS);
    289 
    290 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
    291 			if (m == 0)
    292 				senderr(ENOBUFS);
    293 			ah = mtod(m, struct arc_header *);
    294 			ah->arc_type = atype;
    295 			ah->arc_dhost = adst;
    296 			ah->arc_shost = myself;
    297 			ah->arc_flag = rsflag;
    298 			ah->arc_seqid = ac->ac_seqid;
    299 
    300 			s = splnet();
    301 			/*
    302 			 * Queue message on interface, and start output if
    303 			 * interface not yet active.
    304 			 */
    305 			if (IF_QFULL(&ifp->if_snd)) {
    306 				IF_DROP(&ifp->if_snd);
    307 				splx(s);
    308 				senderr(ENOBUFS);
    309 			}
    310 			ifp->if_obytes += m->m_pkthdr.len;
    311 			IF_ENQUEUE(&ifp->if_snd, m);
    312 			if ((ifp->if_flags & IFF_OACTIVE) == 0)
    313 				(*ifp->if_start)(ifp);
    314 			splx(s);
    315 
    316 			m = m1;
    317 			sflag += 2;
    318 			rsflag = sflag;
    319 		}
    320 		m1 = NULL;
    321 
    322 
    323 		/* here we can have small, especially forbidden packets */
    324 
    325 		if ((m->m_pkthdr.len >=
    326 		    ARC_MIN_FORBID_LEN - ARC_HDRNEWLEN + 2) &&
    327 		    (m->m_pkthdr.len <=
    328 		    ARC_MAX_FORBID_LEN - ARC_HDRNEWLEN + 2)) {
    329 
    330 			M_PREPEND(m, ARC_HDRNEWLEN_EXC, M_DONTWAIT);
    331 			if (m == 0)
    332 				senderr(ENOBUFS);
    333 			ah = mtod(m, struct arc_header *);
    334 			ah->arc_flag = 0xFF;
    335 			ah->arc_seqid = 0xFFFF;
    336 			ah->arc_type2 = atype;
    337 			ah->arc_flag2 = sflag;
    338 			ah->arc_seqid2 = ac->ac_seqid;
    339 		} else {
    340 			M_PREPEND(m, ARC_HDRNEWLEN, M_DONTWAIT);
    341 			if (m == 0)
    342 				senderr(ENOBUFS);
    343 			ah = mtod(m, struct arc_header *);
    344 			ah->arc_flag = sflag;
    345 			ah->arc_seqid = ac->ac_seqid;
    346 		}
    347 
    348 		ah->arc_dhost = adst;
    349 		ah->arc_shost = myself;
    350 		ah->arc_type = atype;
    351 	} else {
    352 		M_PREPEND(m, ARC_HDRLEN, M_DONTWAIT);
    353 		if (m == 0)
    354 			senderr(ENOBUFS);
    355 		ah = mtod(m, struct arc_header *);
    356 		ah->arc_type = atype;
    357 		ah->arc_dhost = adst;
    358 		ah->arc_shost = myself;
    359 	}
    360 	s = splnet();
    361 	/*
    362 	 * Queue message on interface, and start output if interface
    363 	 * not yet active.
    364 	 */
    365 	if (IF_QFULL(&ifp->if_snd)) {
    366 		IF_DROP(&ifp->if_snd);
    367 		splx(s);
    368 		senderr(ENOBUFS);
    369 	}
    370 	ifp->if_obytes += m->m_pkthdr.len;
    371 	IF_ENQUEUE(&ifp->if_snd, m);
    372 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
    373 		(*ifp->if_start)(ifp);
    374 	splx(s);
    375 
    376 	return (error);
    377 
    378 bad:
    379 	if (m1)
    380 		m_freem(m1);
    381 	if (m)
    382 		m_freem(m);
    383 	return (error);
    384 }
    385 
    386 /*
    387  * Defragmenter. Returns mbuf if last packet found, else
    388  * NULL. frees imcoming mbuf as necessary.
    389  */
    390 
    391 __inline struct mbuf *
    392 arc_defrag(ifp, m)
    393 	struct ifnet *ifp;
    394 	struct mbuf *m;
    395 {
    396 	struct arc_header *ah, *ah1;
    397 	struct arccom *ac;
    398 	struct ac_frag *af;
    399 	struct mbuf *m1;
    400 	char *s;
    401 	int newflen;
    402 	u_char src,dst,typ;
    403 
    404 	ac = (struct arccom *)ifp;
    405 
    406 	if (m->m_len < ARC_HDRNEWLEN) {
    407 		m = m_pullup(m, ARC_HDRNEWLEN);
    408 		if (m == NULL) {
    409 			++ifp->if_ierrors;
    410 			return NULL;
    411 		}
    412 	}
    413 
    414 	ah = mtod(m, struct arc_header *);
    415 	typ = ah->arc_type;
    416 
    417 	if (!arc_isphds(typ))
    418 		return m;
    419 
    420 	src = ah->arc_shost;
    421 	dst = ah->arc_dhost;
    422 
    423 	if (ah->arc_flag == 0xff) {
    424 		m_adj(m, 4);
    425 
    426 		if (m->m_len < ARC_HDRNEWLEN) {
    427 			m = m_pullup(m, ARC_HDRNEWLEN);
    428 			if (m == NULL) {
    429 				++ifp->if_ierrors;
    430 				return NULL;
    431 			}
    432 		}
    433 
    434 		ah = mtod(m, struct arc_header *);
    435 	}
    436 
    437 	af = &ac->ac_fragtab[src];
    438 	m1 = af->af_packet;
    439 	s = "debug code error";
    440 
    441 	if (ah->arc_flag & 1) {
    442 		/*
    443 		 * first fragment. We always initialize, which is
    444 		 * about the right thing to do, as we only want to
    445 		 * accept one fragmented packet per src at a time.
    446 		 */
    447 		if (m1 != NULL)
    448 			m_freem(m1);
    449 
    450 		af->af_packet = m;
    451 		m1 = m;
    452 		af->af_maxflag = ah->arc_flag;
    453 		af->af_lastseen = 0;
    454 		af->af_seqid = ah->arc_seqid;
    455 
    456 		return NULL;
    457 		/* notreached */
    458 	} else {
    459 		/* check for unfragmented packet */
    460 		if (ah->arc_flag == 0)
    461 			return m;
    462 
    463 		/* do we have a first packet from that src? */
    464 		if (m1 == NULL) {
    465 			s = "no first frag";
    466 			goto outofseq;
    467 		}
    468 
    469 		ah1 = mtod(m1, struct arc_header *);
    470 
    471 		if (ah->arc_seqid != ah1->arc_seqid) {
    472 			s = "seqid differs";
    473 			goto outofseq;
    474 		}
    475 
    476 		if (typ != ah1->arc_type) {
    477 			s = "type differs";
    478 			goto outofseq;
    479 		}
    480 
    481 		if (dst != ah1->arc_dhost) {
    482 			s = "dest host differs";
    483 			goto outofseq;
    484 		}
    485 
    486 		/* typ, seqid and dst are ok here. */
    487 
    488 		if (ah->arc_flag == af->af_lastseen) {
    489 			m_freem(m);
    490 			return NULL;
    491 		}
    492 
    493 		if (ah->arc_flag == af->af_lastseen + 2) {
    494 			/* ok, this is next fragment */
    495 			af->af_lastseen = ah->arc_flag;
    496 			m_adj(m,ARC_HDRNEWLEN);
    497 
    498 			/*
    499 			 * m_cat might free the first mbuf (with pkthdr)
    500 			 * in 2nd chain; therefore:
    501 			 */
    502 
    503 			newflen = m->m_pkthdr.len;
    504 
    505 			m_cat(m1,m);
    506 
    507 			m1->m_pkthdr.len += newflen;
    508 
    509 			/* is it the last one? */
    510 			if (af->af_lastseen > af->af_maxflag) {
    511 				af->af_packet = NULL;
    512 				return(m1);
    513 			} else
    514 				return NULL;
    515 		}
    516 		s = "other reason";
    517 		/* if all else fails, it is out of sequence, too */
    518 	}
    519 outofseq:
    520 	if (m1) {
    521 		m_freem(m1);
    522 		af->af_packet = NULL;
    523 	}
    524 
    525 	if (m)
    526 		m_freem(m);
    527 
    528 	log(LOG_INFO,"%s: got out of seq. packet: %s\n",
    529 	    ifp->if_xname, s);
    530 
    531 	return NULL;
    532 }
    533 
    534 /*
    535  * return 1 if Packet Header Definition Standard, else 0.
    536  * For now: old IP, old ARP aren't obviously. Lacking correct information,
    537  * we guess that besides new IP and new ARP also IPX and APPLETALK are PHDS.
    538  * (Apple and Novell corporations were involved, among others, in PHDS work).
    539  * Easiest is to assume that everybody else uses that, too.
    540  */
    541 int
    542 arc_isphds(type)
    543 	u_int8_t type;
    544 {
    545 	return (type != ARCTYPE_IP_OLD &&
    546 		type != ARCTYPE_ARP_OLD &&
    547 		type != ARCTYPE_DIAGNOSE);
    548 }
    549 
    550 /*
    551  * Process a received Arcnet packet;
    552  * the packet is in the mbuf chain m with
    553  * the ARCnet header.
    554  */
    555 static void
    556 arc_input(ifp, m)
    557 	struct ifnet *ifp;
    558 	struct mbuf *m;
    559 {
    560 	struct arc_header *ah;
    561 	struct ifqueue *inq;
    562 	u_int8_t atype;
    563 	int s;
    564 	struct arphdr *arph;
    565 
    566 	if ((ifp->if_flags & IFF_UP) == 0) {
    567 		m_freem(m);
    568 		return;
    569 	}
    570 
    571 	/* possibly defragment: */
    572 	m = arc_defrag(ifp, m);
    573 	if (m == NULL)
    574 		return;
    575 
    576 	ah = mtod(m, struct arc_header *);
    577 
    578 	ifp->if_ibytes += m->m_pkthdr.len;
    579 
    580 	if (arcbroadcastaddr == ah->arc_dhost) {
    581 		m->m_flags |= M_BCAST|M_MCAST;
    582 		ifp->if_imcasts++;
    583 	}
    584 
    585 	atype = ah->arc_type;
    586 	switch (atype) {
    587 #ifdef INET
    588 	case ARCTYPE_IP:
    589 		m_adj(m, ARC_HDRNEWLEN);
    590 		schednetisr(NETISR_IP);
    591 		inq = &ipintrq;
    592 		break;
    593 
    594 	case ARCTYPE_IP_OLD:
    595 		m_adj(m, ARC_HDRLEN);
    596 		schednetisr(NETISR_IP);
    597 		inq = &ipintrq;
    598 		break;
    599 
    600 	case ARCTYPE_ARP:
    601 		m_adj(m, ARC_HDRNEWLEN);
    602 		schednetisr(NETISR_ARP);
    603 		inq = &arpintrq;
    604 #ifdef ARCNET_ALLOW_BROKEN_ARP
    605 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
    606 #endif
    607 		break;
    608 
    609 	case ARCTYPE_ARP_OLD:
    610 		m_adj(m, ARC_HDRLEN);
    611 		schednetisr(NETISR_ARP);
    612 		inq = &arpintrq;
    613 		arph = mtod(m, struct arphdr *);
    614 #ifdef ARCNET_ALLOW_BROKEN_ARP
    615 		mtod(m, struct arphdr *)->ar_pro = htons(ETHERTYPE_IP);
    616 #endif
    617 		break;
    618 #endif
    619 #ifdef INET6
    620 	case ARCTYPE_INET6:
    621 		m_adj(m, ARC_HDRNEWLEN);
    622 		schednetisr(NETISR_IPV6);
    623 		inq = &ip6intrq;
    624 		break;
    625 #endif
    626 	default:
    627 		m_freem(m);
    628 		return;
    629 	}
    630 
    631 	s = splnet();
    632 	if (IF_QFULL(inq)) {
    633 		IF_DROP(inq);
    634 		m_freem(m);
    635 	} else
    636 		IF_ENQUEUE(inq, m);
    637 	splx(s);
    638 }
    639 
    640 /*
    641  * Convert Arcnet address to printable (loggable) representation.
    642  */
    643 static char digits[] = "0123456789abcdef";
    644 char *
    645 arc_sprintf(ap)
    646 	u_int8_t *ap;
    647 {
    648 	static char arcbuf[3];
    649 	char *cp = arcbuf;
    650 
    651 	*cp++ = digits[*ap >> 4];
    652 	*cp++ = digits[*ap++ & 0xf];
    653 	*cp   = 0;
    654 	return (arcbuf);
    655 }
    656 
    657 /*
    658  * Register (new) link level address.
    659  */
    660 void
    661 arc_storelladdr(ifp, lla)
    662 	struct ifnet *ifp;
    663 	u_int8_t lla;
    664 {
    665 
    666 	*(LLADDR(ifp->if_sadl)) = lla;
    667 	ifp->if_mtu = ARC_PHDS_MAXMTU;
    668 }
    669 
    670 /*
    671  * Perform common duties while attaching to interface list
    672  */
    673 void
    674 arc_ifattach(ifp, lla)
    675 	struct ifnet *ifp;
    676 	u_int8_t lla;
    677 {
    678 	struct arccom *ac;
    679 
    680 	ifp->if_type = IFT_ARCNET;
    681 	ifp->if_addrlen = 1;
    682 	ifp->if_hdrlen = ARC_HDRLEN;
    683 	ifp->if_dlt = DLT_ARCNET;
    684 	if (ifp->if_flags & IFF_BROADCAST)
    685 		ifp->if_flags |= IFF_MULTICAST|IFF_ALLMULTI;
    686 	if (ifp->if_flags & IFF_LINK0 && arc_ipmtu > ARC_PHDS_MAXMTU)
    687 		log(LOG_ERR,
    688 		    "%s: arc_ipmtu is %d, but must not exceed %d",
    689 		    ifp->if_xname, arc_ipmtu, ARC_PHDS_MAXMTU);
    690 
    691 	ifp->if_output = arc_output;
    692 	ifp->if_input = arc_input;
    693 	ac = (struct arccom *)ifp;
    694 	ac->ac_seqid = (time.tv_sec) & 0xFFFF; /* try to make seqid unique */
    695 	if (lla == 0) {
    696 		/* XXX this message isn't entirely clear, to me -- cgd */
    697 		log(LOG_ERR,"%s: link address 0 reserved for broadcasts.  Please change it and ifconfig %s down up\n",
    698 		   ifp->if_xname, ifp->if_xname);
    699 	}
    700 	if_attach(ifp);
    701 	if_alloc_sadl(ifp);
    702 	arc_storelladdr(ifp, lla);
    703 
    704 	ifp->if_broadcastaddr = &arcbroadcastaddr;
    705 
    706 #if NBPFILTER > 0
    707 	bpfattach(ifp, DLT_ARCNET, ARC_HDRLEN);
    708 #endif
    709 }
    710