xref: /original-bsd/sys/vax/if/if_en.c (revision 792e4f5f)
1 /*
2  * Copyright (c) 1982, 1986 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  *
17  *	@(#)if_en.c	7.5 (Berkeley) 04/25/89
18  */
19 
20 #include "en.h"
21 #if NEN > 0
22 
23 /*
24  * Xerox prototype (3 Mb) Ethernet interface driver.
25  */
26 #include "machine/pte.h"
27 
28 #include "param.h"
29 #include "systm.h"
30 #include "mbuf.h"
31 #include "buf.h"
32 #include "protosw.h"
33 #include "socket.h"
34 #include "vmmac.h"
35 #include "errno.h"
36 #include "ioctl.h"
37 
38 #include "../net/if.h"
39 #include "../net/netisr.h"
40 #include "../net/route.h"
41 
42 #ifdef	INET
43 #include "../netinet/in.h"
44 #include "../netinet/in_systm.h"
45 #include "../netinet/in_var.h"
46 #include "../netinet/ip.h"
47 #endif
48 
49 #ifdef PUP
50 #include "../netpup/pup.h"
51 #include "../netpup/ether.h"
52 #endif
53 
54 #ifdef NS
55 #include "../netns/ns.h"
56 #include "../netns/ns_if.h"
57 #endif
58 
59 #include "../vax/cpu.h"
60 #include "../vax/mtpr.h"
61 #include "if_en.h"
62 #include "if_enreg.h"
63 #include "if_uba.h"
64 #include "../vaxuba/ubareg.h"
65 #include "../vaxuba/ubavar.h"
66 
67 #define	ENMTU	(1024+512)
68 #define	ENMRU	(1024+512+16)		/* 16 is enough to receive trailer */
69 
70 int	enprobe(), enattach(), enrint(), enxint(), encollide();
71 struct	uba_device *eninfo[NEN];
72 u_short enstd[] = { 0 };
73 struct	uba_driver endriver =
74 	{ enprobe, 0, enattach, 0, enstd, "en", eninfo };
75 #define	ENUNIT(x)	minor(x)
76 
77 int	eninit(),oldenoutput(),enreset(),enioctl(), enstart();
78 
79 #ifdef notdef
80 /*
81  * If you need to byte swap IP's in the system, define
82  * this and do a SIOCSIFFLAGS at boot time.
83  */
84 #define	ENF_SWABIPS	0x1000
85 #endif
86 
87 /*
88  * Ethernet software status per interface.
89  *
90  * Each interface is referenced by a network interface structure,
91  * es_if, which the routing code uses to locate the interface.
92  * This structure contains the output queue for the interface, its address, ...
93  * We also have, for each interface, a UBA interface structure, which
94  * contains information about the UNIBUS resources held by the interface:
95  * map registers, buffered data paths, etc.  Information is cached in this
96  * structure for use by the if_uba.c routines in running the interface
97  * efficiently.
98  */
99 struct	en_softc {
100 	struct	ifnet es_if;		/* network-visible interface */
101 	struct	ifuba es_ifuba;		/* UNIBUS resources */
102 	short	es_host;		/* hardware host number */
103 	short	es_delay;		/* current output delay */
104 	short	es_mask;		/* mask for current output delay */
105 	short	es_lastx;		/* host last transmitted to */
106 	short	es_oactive;		/* is output active? */
107 	short	es_olen;		/* length of last output */
108 	short	es_nsactive;		/* is interface enabled for ns? */
109 } en_softc[NEN];
110 
111 /*
112  * Do output DMA to determine interface presence and
113  * interrupt vector.  DMA is too short to disturb other hosts.
114  */
115 enprobe(reg)
116 	caddr_t reg;
117 {
118 	register int br, cvec;		/* r11, r10 value-result */
119 	register struct endevice *addr = (struct endevice *)reg;
120 
121 #ifdef lint
122 	br = 0; cvec = br; br = cvec;
123 	enrint(0); enxint(0); encollide(0);
124 #endif
125 	addr->en_istat = 0;
126 	addr->en_owc = -1;
127 	addr->en_oba = 0;
128 	addr->en_ostat = EN_IEN|EN_GO;
129 	DELAY(100000);
130 	addr->en_ostat = 0;
131 	return (1);
132 }
133 
134 /*
135  * Interface exists: make available by filling in network interface
136  * record.  System will initialize the interface when it is ready
137  * to accept packets.
138  */
139 enattach(ui)
140 	struct uba_device *ui;
141 {
142 	register struct en_softc *es = &en_softc[ui->ui_unit];
143 
144 	es->es_if.if_unit = ui->ui_unit;
145 	es->es_if.if_name = "en";
146 	es->es_if.if_mtu = ENMTU;
147 	es->es_if.if_flags = IFF_BROADCAST;
148 	es->es_if.if_init = eninit;
149 	es->es_if.if_output = oldenoutput;
150 	es->es_if.if_start = enstart;
151 	es->es_if.if_ioctl = enioctl;
152 	es->es_if.if_reset = enreset;
153 	es->es_ifuba.ifu_flags = UBA_NEEDBDP | UBA_NEED16 | UBA_CANTWAIT;
154 #if defined(VAX750)
155 	/* don't chew up 750 bdp's */
156 	if (cpu == VAX_750 && ui->ui_unit > 0)
157 		es->es_ifuba.ifu_flags &= ~UBA_NEEDBDP;
158 #endif
159 	if_attach(&es->es_if);
160 }
161 
162 /*
163  * Reset of interface after UNIBUS reset.
164  * If interface is on specified uba, reset its state.
165  */
166 enreset(unit, uban)
167 	int unit, uban;
168 {
169 	register struct uba_device *ui;
170 
171 	if (unit >= NEN || (ui = eninfo[unit]) == 0 || ui->ui_alive == 0 ||
172 	    ui->ui_ubanum != uban)
173 		return;
174 	printf(" en%d", unit);
175 	eninit(unit);
176 }
177 
178 /*
179  * Initialization of interface; clear recorded pending
180  * operations, and reinitialize UNIBUS usage.
181  */
182 eninit(unit)
183 	int unit;
184 {
185 	register struct en_softc *es = &en_softc[unit];
186 	register struct uba_device *ui = eninfo[unit];
187 	register struct endevice *addr;
188 	int s;
189 
190 	if (es->es_if.if_addrlist == (struct ifaddr *)0)
191 		return;
192 	if (if_ubainit(&es->es_ifuba, ui->ui_ubanum,
193 	    sizeof (struct en_header), (int)btoc(ENMRU)) == 0) {
194 		printf("en%d: can't initialize\n", unit);
195 		es->es_if.if_flags &= ~IFF_UP;
196 		return;
197 	}
198 	addr = (struct endevice *)ui->ui_addr;
199 	addr->en_istat = addr->en_ostat = 0;
200 
201 	/*
202 	 * Hang a receive and start any
203 	 * pending writes by faking a transmit complete.
204 	 */
205 	s = splimp();
206 	addr->en_iba = es->es_ifuba.ifu_r.ifrw_info;
207 	addr->en_iwc = -(sizeof (struct en_header) + ENMRU) >> 1;
208 	addr->en_istat = EN_IEN|EN_GO;
209 	es->es_oactive = 1;
210 	es->es_if.if_flags |= IFF_RUNNING;
211 	enxint(unit);
212 	splx(s);
213 }
214 
215 int	enalldelay = 0;
216 int	enlastdel = 50;
217 int	enlastmask = (~0) << 5;
218 
219 /*
220  * Start or restart output on interface.
221  * If interface is already active, then this is a retransmit
222  * after a collision, and just restuff registers and delay.
223  * If interface is not already active, get another datagram
224  * to send off of the interface queue, and map it to the interface
225  * before starting the output.
226  */
227 enstart(dev)
228 	dev_t dev;
229 {
230         int unit = ENUNIT(dev);
231 	struct uba_device *ui = eninfo[unit];
232 	register struct en_softc *es = &en_softc[unit];
233 	register struct endevice *addr;
234 	register struct en_header *en;
235 	struct mbuf *m;
236 	int dest;
237 
238 	if (es->es_oactive)
239 		goto restart;
240 
241 	/*
242 	 * Not already active: dequeue another request
243 	 * and map it to the UNIBUS.  If no more requests,
244 	 * just return.
245 	 */
246 	IF_DEQUEUE(&es->es_if.if_snd, m);
247 	if (m == 0) {
248 		es->es_oactive = 0;
249 		return;
250 	}
251 	en = mtod(m, struct en_header *);
252 	dest = en->en_dhost;
253 	en->en_shost = es->es_host;
254 	es->es_olen = if_wubaput(&es->es_ifuba, m);
255 #ifdef ENF_SWABIPS
256 	/*
257 	 * The Xerox interface does word at a time DMA, so
258 	 * someone must do byte swapping of user data if high
259 	 * and low ender machines are to communicate.  It doesn't
260 	 * belong here, but certain people depend on it, so...
261 	 *
262 	 * Should swab everybody, but this is a kludge anyway.
263 	 */
264 	if (es->es_if.if_flags & ENF_SWABIPS) {
265 		en = (struct en_header *)es->es_ifuba.ifu_w.ifrw_addr;
266 		if (en->en_type == ENTYPE_IP)
267 			enswab((caddr_t)(en + 1), (caddr_t)(en + 1),
268 			    es->es_olen - sizeof (struct en_header) + 1);
269 	}
270 #endif
271 
272 	/*
273 	 * Ethernet cannot take back-to-back packets (no
274 	 * buffering in interface.  To help avoid overrunning
275 	 * receivers, enforce a small delay (about 1ms) in interface:
276 	 *	* between all packets when enalldelay
277 	 *	* whenever last packet was broadcast
278 	 *	* whenever this packet is to same host as last packet
279 	 */
280 	if (enalldelay || es->es_lastx == 0 || es->es_lastx == dest) {
281 		es->es_delay = enlastdel;
282 		es->es_mask = enlastmask;
283 	}
284 	es->es_lastx = dest;
285 
286 restart:
287 	/*
288 	 * Have request mapped to UNIBUS for transmission.
289 	 * Purge any stale data from this BDP, and start the otput.
290 	 */
291 	if (es->es_ifuba.ifu_flags & UBA_NEEDBDP)
292 		UBAPURGE(es->es_ifuba.ifu_uba, es->es_ifuba.ifu_w.ifrw_bdp);
293 	addr = (struct endevice *)ui->ui_addr;
294 	addr->en_oba = (int)es->es_ifuba.ifu_w.ifrw_info;
295 	addr->en_odelay = es->es_delay;
296 	addr->en_owc = -((es->es_olen + 1) >> 1);
297 	addr->en_ostat = EN_IEN|EN_GO;
298 	es->es_oactive = 1;
299 }
300 
301 /*
302  * Ethernet interface transmitter interrupt.
303  * Start another output if more data to send.
304  */
305 enxint(unit)
306 	int unit;
307 {
308 	register struct uba_device *ui = eninfo[unit];
309 	register struct en_softc *es = &en_softc[unit];
310 	register struct endevice *addr = (struct endevice *)ui->ui_addr;
311 
312 	if (es->es_oactive == 0)
313 		return;
314 	if (es->es_mask && (addr->en_ostat&EN_OERROR)) {
315 		es->es_if.if_oerrors++;
316 		endocoll(unit);
317 		return;
318 	}
319 	es->es_if.if_opackets++;
320 	es->es_oactive = 0;
321 	es->es_delay = 0;
322 	es->es_mask = ~0;
323 	if (es->es_ifuba.ifu_xtofree) {
324 		m_freem(es->es_ifuba.ifu_xtofree);
325 		es->es_ifuba.ifu_xtofree = 0;
326 	}
327 	if (es->es_if.if_snd.ifq_head == 0) {
328 		es->es_lastx = 256;		/* putatively illegal */
329 		return;
330 	}
331 	enstart(unit);
332 }
333 
334 /*
335  * Collision on ethernet interface.  Do exponential
336  * backoff, and retransmit.  If have backed off all
337  * the way print warning diagnostic, and drop packet.
338  */
339 encollide(unit)
340 	int unit;
341 {
342 	struct en_softc *es = &en_softc[unit];
343 
344 	es->es_if.if_collisions++;
345 	if (es->es_oactive == 0)
346 		return;
347 	endocoll(unit);
348 }
349 
350 endocoll(unit)
351 	int unit;
352 {
353 	register struct en_softc *es = &en_softc[unit];
354 
355 	/*
356 	 * Es_mask is a 16 bit number with n low zero bits, with
357 	 * n the number of backoffs.  When es_mask is 0 we have
358 	 * backed off 16 times, and give up.
359 	 */
360 	if (es->es_mask == 0) {
361 		printf("en%d: send error\n", unit);
362 		enxint(unit);
363 		return;
364 	}
365 	/*
366 	 * Another backoff.  Restart with delay based on n low bits
367 	 * of the interval timer.
368 	 */
369 	es->es_mask <<= 1;
370 	es->es_delay = mfpr(ICR) &~ es->es_mask;
371 	enstart(unit);
372 }
373 
374 #ifdef notdef
375 struct	sockproto enproto = { AF_ETHERLINK };
376 struct	sockaddr_en endst = { sizeof(endst), AF_ETHERLINK };
377 struct	sockaddr_en ensrc = { sizeof(ensrc), AF_ETHERLINK };
378 #endif
379 /*
380  * Ethernet interface receiver interrupt.
381  * If input error just drop packet.
382  * Otherwise purge input buffered data path and examine
383  * packet to determine type.  If can't determine length
384  * from type, then have to drop packet.  Othewise decapsulate
385  * packet based on type and pass to type specific higher-level
386  * input routine.
387  */
388 enrint(unit)
389 	int unit;
390 {
391 	register struct en_softc *es = &en_softc[unit];
392 	struct endevice *addr = (struct endevice *)eninfo[unit]->ui_addr;
393 	register struct en_header *en;
394     	struct mbuf *m;
395 	int len; short resid;
396 	register struct ifqueue *inq;
397 	int off, s;
398 
399 	es->es_if.if_ipackets++;
400 
401 	/*
402 	 * Purge BDP; drop if input error indicated.
403 	 */
404 	if (es->es_ifuba.ifu_flags & UBA_NEEDBDP)
405 		UBAPURGE(es->es_ifuba.ifu_uba, es->es_ifuba.ifu_r.ifrw_bdp);
406 	if (addr->en_istat&EN_IERROR) {
407 		es->es_if.if_ierrors++;
408 		goto setup;
409 	}
410 
411 	/*
412 	 * Calculate input data length.
413 	 * Get pointer to ethernet header (in input buffer).
414 	 * Deal with trailer protocol: if type is PUP trailer
415 	 * get true type from first 16-bit word past data.
416 	 * Remember that type was trailer by setting off.
417 	 */
418 	resid = addr->en_iwc;
419 	if (resid)
420 		resid |= 0176000;
421 	len = (((sizeof (struct en_header) + ENMRU) >> 1) + resid) << 1;
422 	len -= sizeof (struct en_header);
423 	if (len > ENMRU)
424 		goto setup;			/* sanity */
425 	en = (struct en_header *)(es->es_ifuba.ifu_r.ifrw_addr);
426 	en->en_type = ntohs(en->en_type);
427 #define	endataaddr(en, off, type)	((type)(((caddr_t)((en)+1)+(off))))
428 	if (en->en_type >= ENTYPE_TRAIL &&
429 	    en->en_type < ENTYPE_TRAIL+ENTYPE_NTRAILER) {
430 		off = (en->en_type - ENTYPE_TRAIL) * 512;
431 		if (off > ENMTU)
432 			goto setup;		/* sanity */
433 		en->en_type = ntohs(*endataaddr(en, off, u_short *));
434 		resid = ntohs(*(endataaddr(en, off+2, u_short *)));
435 		if (off + resid > len)
436 			goto setup;		/* sanity */
437 		len = off + resid;
438 	} else
439 		off = 0;
440 	if (len == 0)
441 		goto setup;
442 #ifdef ENF_SWABIPS
443 	if (es->es_if.if_flags & ENF_SWABIPS && en->en_type == ENTYPE_IP)
444 		enswab((caddr_t)(en + 1), (caddr_t)(en + 1), len);
445 #endif
446 	/*
447 	 * Pull packet off interface.  Off is nonzero if packet
448 	 * has trailing header; if_rubaget will then force this header
449 	 * information to be at the front, but we still have to drop
450 	 * the type and length which are at the front of any trailer data.
451 	 */
452 	m = if_rubaget(&es->es_ifuba, len, off, &es->es_if);
453 	if (m == 0)
454 		goto setup;
455 	switch (en->en_type) {
456 
457 #ifdef INET
458 	case ENTYPE_IP:
459 		schednetisr(NETISR_IP);
460 		inq = &ipintrq;
461 		break;
462 #endif
463 #ifdef PUP
464 	case ENTYPE_PUP:
465 		rpup_input(m);
466 		goto setup;
467 #endif
468 #ifdef NS
469 	case ETHERTYPE_NS:
470 		if (es->es_nsactive) {
471 			schednetisr(NETISR_NS);
472 			inq = &nsintrq;
473 		} else {
474 			m_freem(m);
475 			goto setup;
476 		}
477 		break;
478 #endif
479 
480 	default:
481 #ifdef notdef
482 		enproto.sp_protocol = en->en_type;
483 		endst.sen_host = en->en_dhost;
484 		endst.sen_net = ensrc.sen_net = es->es_if.if_net;
485 		ensrc.sen_host = en->en_shost;
486 		raw_input(m, &enproto,
487 		    (struct sockaddr *)&ensrc, (struct sockaddr *)&endst);
488 #else
489 		m_freem(m);
490 #endif
491 		goto setup;
492 	}
493 
494 	s = splimp();
495 	if (IF_QFULL(inq)) {
496 		IF_DROP(inq);
497 		m_freem(m);
498 	} else
499 		IF_ENQUEUE(inq, m);
500 	splx(s);
501 
502 setup:
503 	/*
504 	 * Reset for next packet.
505 	 */
506 	addr->en_iba = es->es_ifuba.ifu_r.ifrw_info;
507 	addr->en_iwc = -(sizeof (struct en_header) + ENMRU) >> 1;
508 	addr->en_istat = EN_IEN|EN_GO;
509 }
510 
511 /*
512  * Ethernet output routine.
513  * Encapsulate a packet of type family for the local net.
514  * Use trailer local net encapsulation if enough data in first
515  * packet leaves a multiple of 512 bytes of data in remainder.
516  */
517 oldenoutput(ifp, m0, dst)
518 	struct ifnet *ifp;
519 	struct mbuf *m0;
520 	struct sockaddr *dst;
521 {
522 	int type, dest, s, error;
523 	register struct mbuf *m = m0;
524 	register struct en_header *en;
525 	register int off;
526 
527 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
528 		error = ENETDOWN;
529 		goto bad;
530 	}
531 	switch (dst->sa_family) {
532 
533 #ifdef INET
534 	case AF_INET:
535 		{
536 		struct in_addr in;
537 
538 		in = ((struct sockaddr_in *)dst)->sin_addr;
539 		if (in_broadcast(in))
540 			dest = EN_BROADCAST;
541 		else
542 			dest = in_lnaof(in);
543 		}
544 		if (dest >= 0x100) {
545 			error = EPERM;		/* ??? */
546 			goto bad;
547 		}
548 		off = m->m_pkthdr.len - m->m_len;
549 		/* need per host negotiation */
550 		if ((ifp->if_flags & IFF_NOTRAILERS) == 0)
551 		if (off > 0 && (off & 0x1ff) == 0 &&
552 		    (m->m_flags & M_EXT) == 0 &&
553 		    m->m_data >= m->m_pktdat + 2 * sizeof (u_short)) {
554 			type = ENTYPE_TRAIL + (off>>9);
555 			m->m_data -= 2 * sizeof (u_short);
556 			m->m_len += 2 * sizeof (u_short);
557 			*mtod(m, u_short *) = htons((u_short)ENTYPE_IP);
558 			*(mtod(m, u_short *) + 1) = ntohs((u_short)m->m_len);
559 			goto gottrailertype;
560 		}
561 		type = ENTYPE_IP;
562 		off = 0;
563 		goto gottype;
564 #endif
565 #ifdef NS
566 	case AF_NS:
567 	{
568 		u_char *up;
569 
570 		type = ETHERTYPE_NS;
571 		up = ((struct sockaddr_ns *)dst)->sns_addr.x_host.c_host;
572 		if (*up & 1)
573 			dest = EN_BROADCAST;
574 		else
575 			dest = up[5];
576 
577 		off = 0;
578 		goto gottype;
579 	}
580 #endif
581 #ifdef PUP
582 	case AF_PUP:
583 		dest = ((struct sockaddr_pup *)dst)->spup_host;
584 		type = ENTYPE_PUP;
585 		off = 0;
586 		goto gottype;
587 #endif
588 
589 #ifdef notdef
590 	case AF_ETHERLINK:
591 		goto gotheader;
592 #endif
593 
594 	default:
595 		printf("en%d: can't handle af%d\n", ifp->if_unit,
596 			dst->sa_family);
597 		error = EAFNOSUPPORT;
598 		goto bad;
599 	}
600 
601 gottrailertype:
602 	/*
603 	 * Packet to be sent as trailer: move first packet
604 	 * (control information) to end of chain.
605 	 */
606 	while (m->m_next)
607 		m = m->m_next;
608 	m->m_next = m0;
609 	m = m0->m_next;
610 	m0->m_next = 0;
611 	m0 = m;
612 
613 gottype:
614 	/*
615 	 * Add local net header.  If no space in first mbuf,
616 	 * allocate another.
617 	 */
618 	M_PREPEND(m, sizeof (struct en_header), M_DONTWAIT);
619 	if (m == NULL)
620 		return (ENOBUFS);
621 	en = mtod(m, struct en_header *);
622 	/* add en_shost later */
623 	en->en_dhost = dest;
624 	en->en_type = htons((u_short)type);
625 
626 #ifdef notdef
627 gotheader:
628 #endif
629 	/*
630 	 * Queue message on interface, and start output if interface
631 	 * not yet active.
632 	 */
633 	s = splimp();
634 	if (IF_QFULL(&ifp->if_snd)) {
635 		IF_DROP(&ifp->if_snd);
636 		error = ENOBUFS;
637 		goto qfull;
638 	}
639 	IF_ENQUEUE(&ifp->if_snd, m);
640 	if (en_softc[ifp->if_unit].es_oactive == 0)
641 		enstart(ifp->if_unit);
642 	splx(s);
643 	return (0);
644 qfull:
645 	m0 = m;
646 	splx(s);
647 bad:
648 	m_freem(m0);
649 	return (error);
650 }
651 
652 /*
653  * Process an ioctl request.
654  */
655 enioctl(ifp, cmd, data)
656 	register struct ifnet *ifp;
657 	int cmd;
658 	caddr_t data;
659 {
660 	register struct en_softc *es = ((struct en_softc *)ifp);
661 	struct ifaddr *ifa = (struct ifaddr *) data;
662 	int s = splimp(), error = 0;
663 	struct endevice *enaddr;
664 
665 	switch (cmd) {
666 
667 	case SIOCSIFADDR:
668 		enaddr = (struct endevice *)eninfo[ifp->if_unit]->ui_addr;
669 		es->es_host = (~enaddr->en_addr) & 0xff;
670 		/*
671 		 * Attempt to check agreement of protocol address
672 		 * and board address.
673 		 */
674 		switch (ifa->ifa_addr->sa_family) {
675 		case AF_INET:
676 			if (in_lnaof(IA_SIN(ifa)->sin_addr) != es->es_host)
677 				return (EADDRNOTAVAIL);
678 			break;
679 #ifdef NS
680 		case AF_NS:
681 			if (IA_SNS(ifa)->sns_addr.x_host.c_host[5]
682 							!= es->es_host)
683 				return (EADDRNOTAVAIL);
684 			es->es_nsactive = 1;
685 			break;
686 #endif
687 		}
688 		ifp->if_flags |= IFF_UP;
689 		if ((ifp->if_flags & IFF_RUNNING) == 0)
690 			eninit(ifp->if_unit);
691 		break;
692 
693 	default:
694 		error = EINVAL;
695 		break;
696 	}
697 	splx(s);
698 	return (error);
699 }
700 
701 #ifdef ENF_SWABIPS
702 /*
703  * Swab bytes
704  * Jeffrey Mogul, Stanford
705  */
706 enswab(from, to, n)
707 	register unsigned char *from, *to;
708 	register int n;
709 {
710 	register unsigned long temp;
711 
712 	if ((n <= 0) || (n > 0xFFFF)) {
713 		printf("enswab: bad len %d\n", n);
714 		return;
715 	}
716 
717 	n >>= 1; n++;
718 #define	STEP	{temp = *from++;*to++ = *from++;*to++ = temp;}
719 	/* round to multiple of 8 */
720 	while ((--n) & 07)
721 		STEP;
722 	n >>= 3;
723 	while (--n >= 0) {
724 		STEP; STEP; STEP; STEP;
725 		STEP; STEP; STEP; STEP;
726 	}
727 }
728 #endif
729 #endif
730