xref: /dragonfly/sys/net/bpf.c (revision 235099c3)
1 /*
2  * Copyright (c) 1990, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from the Stanford/CMU enet packet filter,
6  * (net/enet.c) distributed as part of 4.3BSD, and code contributed
7  * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
8  * Berkeley Laboratory.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *      @(#)bpf.c	8.2 (Berkeley) 3/28/94
39  *
40  * $FreeBSD: src/sys/net/bpf.c,v 1.59.2.12 2002/04/14 21:41:48 luigi Exp $
41  * $DragonFly: src/sys/net/bpf.c,v 1.50 2008/09/23 11:28:49 sephe Exp $
42  */
43 
44 #include "use_bpf.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/conf.h>
49 #include <sys/device.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/time.h>
53 #include <sys/proc.h>
54 #include <sys/signalvar.h>
55 #include <sys/filio.h>
56 #include <sys/sockio.h>
57 #include <sys/ttycom.h>
58 #include <sys/filedesc.h>
59 
60 #include <sys/poll.h>
61 
62 #include <sys/socket.h>
63 #include <sys/vnode.h>
64 
65 #include <sys/thread2.h>
66 
67 #include <net/if.h>
68 #include <net/bpf.h>
69 #include <net/bpfdesc.h>
70 #include <net/netmsg2.h>
71 
72 #include <netinet/in.h>
73 #include <netinet/if_ether.h>
74 #include <sys/kernel.h>
75 #include <sys/sysctl.h>
76 
77 #include <sys/devfs.h>
78 
79 struct netmsg_bpf_output {
80 	struct netmsg	nm_netmsg;
81 	struct mbuf	*nm_mbuf;
82 	struct ifnet	*nm_ifp;
83 	struct sockaddr	*nm_dst;
84 };
85 
86 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
87 DEVFS_DECLARE_CLONE_BITMAP(bpf);
88 
89 #if NBPF <= 1
90 #define BPF_PREALLOCATED_UNITS	4
91 #else
92 #define BPF_PREALLOCATED_UNITS	NBPF
93 #endif
94 
95 #if NBPF > 0
96 
97 /*
98  * The default read buffer size is patchable.
99  */
100 static int bpf_bufsize = BPF_DEFAULTBUFSIZE;
101 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
102 	   &bpf_bufsize, 0, "");
103 int bpf_maxbufsize = BPF_MAXBUFSIZE;
104 SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
105 	   &bpf_maxbufsize, 0, "");
106 
107 /*
108  *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
109  */
110 static struct bpf_if	*bpf_iflist;
111 
112 static int	bpf_allocbufs(struct bpf_d *);
113 static void	bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
114 static void	bpf_detachd(struct bpf_d *d);
115 static void	bpf_resetd(struct bpf_d *);
116 static void	bpf_freed(struct bpf_d *);
117 static void	bpf_mcopy(const void *, void *, size_t);
118 static int	bpf_movein(struct uio *, int, struct mbuf **,
119 			   struct sockaddr *, int *, struct bpf_insn *);
120 static int	bpf_setif(struct bpf_d *, struct ifreq *);
121 static void	bpf_timed_out(void *);
122 static void	bpf_wakeup(struct bpf_d *);
123 static void	catchpacket(struct bpf_d *, u_char *, u_int, u_int,
124 			    void (*)(const void *, void *, size_t),
125 			    const struct timeval *);
126 static int	bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
127 static int	bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
128 static int	bpf_setdlt(struct bpf_d *, u_int);
129 static void	bpf_drvinit(void *unused);
130 
131 static d_open_t		bpfopen;
132 static d_clone_t	bpfclone;
133 static d_close_t	bpfclose;
134 static d_read_t		bpfread;
135 static d_write_t	bpfwrite;
136 static d_ioctl_t	bpfioctl;
137 static d_poll_t		bpfpoll;
138 
139 #define CDEV_MAJOR 23
140 static struct dev_ops bpf_ops = {
141 	{ "bpf", CDEV_MAJOR, 0 },
142 	.d_open =	bpfopen,
143 	.d_close =	bpfclose,
144 	.d_read =	bpfread,
145 	.d_write =	bpfwrite,
146 	.d_ioctl =	bpfioctl,
147 	.d_poll =	bpfpoll,
148 };
149 
150 
151 static int
152 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp,
153 	   struct sockaddr *sockp, int *datlen, struct bpf_insn *wfilter)
154 {
155 	struct mbuf *m;
156 	int error;
157 	int len;
158 	int hlen;
159 	int slen;
160 
161 	*datlen = 0;
162 	*mp = NULL;
163 
164 	/*
165 	 * Build a sockaddr based on the data link layer type.
166 	 * We do this at this level because the ethernet header
167 	 * is copied directly into the data field of the sockaddr.
168 	 * In the case of SLIP, there is no header and the packet
169 	 * is forwarded as is.
170 	 * Also, we are careful to leave room at the front of the mbuf
171 	 * for the link level header.
172 	 */
173 	switch (linktype) {
174 	case DLT_SLIP:
175 		sockp->sa_family = AF_INET;
176 		hlen = 0;
177 		break;
178 
179 	case DLT_EN10MB:
180 		sockp->sa_family = AF_UNSPEC;
181 		/* XXX Would MAXLINKHDR be better? */
182 		hlen = sizeof(struct ether_header);
183 		break;
184 
185 	case DLT_RAW:
186 	case DLT_NULL:
187 		sockp->sa_family = AF_UNSPEC;
188 		hlen = 0;
189 		break;
190 
191 	case DLT_ATM_RFC1483:
192 		/*
193 		 * en atm driver requires 4-byte atm pseudo header.
194 		 * though it isn't standard, vpi:vci needs to be
195 		 * specified anyway.
196 		 */
197 		sockp->sa_family = AF_UNSPEC;
198 		hlen = 12;	/* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
199 		break;
200 
201 	case DLT_PPP:
202 		sockp->sa_family = AF_UNSPEC;
203 		hlen = 4;	/* This should match PPP_HDRLEN */
204 		break;
205 
206 	default:
207 		return(EIO);
208 	}
209 
210 	len = uio->uio_resid;
211 	*datlen = len - hlen;
212 	if ((unsigned)len > MCLBYTES)
213 		return(EIO);
214 
215 	m = m_getl(len, MB_WAIT, MT_DATA, M_PKTHDR, NULL);
216 	if (m == NULL)
217 		return(ENOBUFS);
218 	m->m_pkthdr.len = m->m_len = len;
219 	m->m_pkthdr.rcvif = NULL;
220 	*mp = m;
221 
222 	if (m->m_len < hlen) {
223 		error = EPERM;
224 		goto bad;
225 	}
226 
227 	error = uiomove(mtod(m, u_char *), len, uio);
228 	if (error)
229 		goto bad;
230 
231 	slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
232 	if (slen == 0) {
233 		error = EPERM;
234 		goto bad;
235 	}
236 
237 	/*
238 	 * Make room for link header, and copy it to sockaddr.
239 	 */
240 	if (hlen != 0) {
241 		bcopy(m->m_data, sockp->sa_data, hlen);
242 		m->m_pkthdr.len -= hlen;
243 		m->m_len -= hlen;
244 		m->m_data += hlen; /* XXX */
245 	}
246 	return (0);
247 bad:
248 	m_freem(m);
249 	return(error);
250 }
251 
252 /*
253  * Attach file to the bpf interface, i.e. make d listen on bp.
254  * Must be called at splimp.
255  */
256 static void
257 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
258 {
259 	/*
260 	 * Point d at bp, and add d to the interface's list of listeners.
261 	 * Finally, point the driver's bpf cookie at the interface so
262 	 * it will divert packets to bpf.
263 	 */
264 	d->bd_bif = bp;
265 	SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
266 	*bp->bif_driverp = bp;
267 }
268 
269 /*
270  * Detach a file from its interface.
271  */
272 static void
273 bpf_detachd(struct bpf_d *d)
274 {
275 	int error;
276 	struct bpf_if *bp;
277 	struct ifnet *ifp;
278 
279 	bp = d->bd_bif;
280 	ifp = bp->bif_ifp;
281 
282 	/* Remove d from the interface's descriptor list. */
283 	SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
284 
285 	if (SLIST_EMPTY(&bp->bif_dlist)) {
286 		/*
287 		 * Let the driver know that there are no more listeners.
288 		 */
289 		*bp->bif_driverp = NULL;
290 	}
291 	d->bd_bif = NULL;
292 	/*
293 	 * Check if this descriptor had requested promiscuous mode.
294 	 * If so, turn it off.
295 	 */
296 	if (d->bd_promisc) {
297 		d->bd_promisc = 0;
298 		error = ifpromisc(ifp, 0);
299 		if (error != 0 && error != ENXIO) {
300 			/*
301 			 * ENXIO can happen if a pccard is unplugged,
302 			 * Something is really wrong if we were able to put
303 			 * the driver into promiscuous mode, but can't
304 			 * take it out.
305 			 */
306 			if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
307 				  error);
308 		}
309 	}
310 }
311 
312 /*
313  * Open ethernet device.  Returns ENXIO for illegal minor device number,
314  * EBUSY if file is open by another process.
315  */
316 /* ARGSUSED */
317 static int
318 bpfopen(struct dev_open_args *ap)
319 {
320 	cdev_t dev = ap->a_head.a_dev;
321 	struct bpf_d *d;
322 
323 	if (ap->a_cred->cr_prison)
324 		return(EPERM);
325 
326 	d = dev->si_drv1;
327 	/*
328 	 * Each minor can be opened by only one process.  If the requested
329 	 * minor is in use, return EBUSY.
330 	 */
331 	if (d != NULL)
332 		return(EBUSY);
333 
334 	MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
335 	dev->si_drv1 = d;
336 	d->bd_bufsize = bpf_bufsize;
337 	d->bd_sig = SIGIO;
338 	d->bd_seesent = 1;
339 	callout_init(&d->bd_callout);
340 	return(0);
341 }
342 
343 static int
344 bpfclone(struct dev_clone_args *ap)
345 {
346 	int unit;
347 
348 	unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(bpf), 0);
349 	ap->a_dev = make_only_dev(&bpf_ops, unit, 0, 0, 0600, "bpf%d", unit);
350 
351 	return 0;
352 }
353 
354 /*
355  * Close the descriptor by detaching it from its interface,
356  * deallocating its buffers, and marking it free.
357  */
358 /* ARGSUSED */
359 static int
360 bpfclose(struct dev_close_args *ap)
361 {
362 	cdev_t dev = ap->a_head.a_dev;
363 	struct bpf_d *d = dev->si_drv1;
364 
365 	funsetown(d->bd_sigio);
366 	crit_enter();
367 	if (d->bd_state == BPF_WAITING)
368 		callout_stop(&d->bd_callout);
369 	d->bd_state = BPF_IDLE;
370 	if (d->bd_bif != NULL)
371 		bpf_detachd(d);
372 	crit_exit();
373 	bpf_freed(d);
374 	dev->si_drv1 = NULL;
375 	if (dev->si_uminor >= BPF_PREALLOCATED_UNITS) {
376 		devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(bpf), dev->si_uminor);
377 		destroy_dev(dev);
378 	}
379 	kfree(d, M_BPF);
380 	return(0);
381 }
382 
383 /*
384  * Rotate the packet buffers in descriptor d.  Move the store buffer
385  * into the hold slot, and the free buffer into the store slot.
386  * Zero the length of the new store buffer.
387  */
388 #define ROTATE_BUFFERS(d) \
389 	(d)->bd_hbuf = (d)->bd_sbuf; \
390 	(d)->bd_hlen = (d)->bd_slen; \
391 	(d)->bd_sbuf = (d)->bd_fbuf; \
392 	(d)->bd_slen = 0; \
393 	(d)->bd_fbuf = NULL;
394 /*
395  *  bpfread - read next chunk of packets from buffers
396  */
397 static int
398 bpfread(struct dev_read_args *ap)
399 {
400 	cdev_t dev = ap->a_head.a_dev;
401 	struct bpf_d *d = dev->si_drv1;
402 	int timed_out;
403 	int error;
404 
405 	/*
406 	 * Restrict application to use a buffer the same size as
407 	 * as kernel buffers.
408 	 */
409 	if (ap->a_uio->uio_resid != d->bd_bufsize)
410 		return(EINVAL);
411 
412 	crit_enter();
413 	if (d->bd_state == BPF_WAITING)
414 		callout_stop(&d->bd_callout);
415 	timed_out = (d->bd_state == BPF_TIMED_OUT);
416 	d->bd_state = BPF_IDLE;
417 	/*
418 	 * If the hold buffer is empty, then do a timed sleep, which
419 	 * ends when the timeout expires or when enough packets
420 	 * have arrived to fill the store buffer.
421 	 */
422 	while (d->bd_hbuf == NULL) {
423 		if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
424 			/*
425 			 * A packet(s) either arrived since the previous
426 			 * read or arrived while we were asleep.
427 			 * Rotate the buffers and return what's here.
428 			 */
429 			ROTATE_BUFFERS(d);
430 			break;
431 		}
432 
433 		/*
434 		 * No data is available, check to see if the bpf device
435 		 * is still pointed at a real interface.  If not, return
436 		 * ENXIO so that the userland process knows to rebind
437 		 * it before using it again.
438 		 */
439 		if (d->bd_bif == NULL) {
440 			crit_exit();
441 			return(ENXIO);
442 		}
443 
444 		if (ap->a_ioflag & IO_NDELAY) {
445 			crit_exit();
446 			return(EWOULDBLOCK);
447 		}
448 		error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
449 		if (error == EINTR || error == ERESTART) {
450 			crit_exit();
451 			return(error);
452 		}
453 		if (error == EWOULDBLOCK) {
454 			/*
455 			 * On a timeout, return what's in the buffer,
456 			 * which may be nothing.  If there is something
457 			 * in the store buffer, we can rotate the buffers.
458 			 */
459 			if (d->bd_hbuf)
460 				/*
461 				 * We filled up the buffer in between
462 				 * getting the timeout and arriving
463 				 * here, so we don't need to rotate.
464 				 */
465 				break;
466 
467 			if (d->bd_slen == 0) {
468 				crit_exit();
469 				return(0);
470 			}
471 			ROTATE_BUFFERS(d);
472 			break;
473 		}
474 	}
475 	/*
476 	 * At this point, we know we have something in the hold slot.
477 	 */
478 	crit_exit();
479 
480 	/*
481 	 * Move data from hold buffer into user space.
482 	 * We know the entire buffer is transferred since
483 	 * we checked above that the read buffer is bpf_bufsize bytes.
484 	 */
485 	error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
486 
487 	crit_enter();
488 	d->bd_fbuf = d->bd_hbuf;
489 	d->bd_hbuf = NULL;
490 	d->bd_hlen = 0;
491 	crit_exit();
492 
493 	return(error);
494 }
495 
496 
497 /*
498  * If there are processes sleeping on this descriptor, wake them up.
499  */
500 static void
501 bpf_wakeup(struct bpf_d *d)
502 {
503 	if (d->bd_state == BPF_WAITING) {
504 		callout_stop(&d->bd_callout);
505 		d->bd_state = BPF_IDLE;
506 	}
507 	wakeup(d);
508 	if (d->bd_async && d->bd_sig && d->bd_sigio)
509 		pgsigio(d->bd_sigio, d->bd_sig, 0);
510 
511 	get_mplock();
512 	selwakeup(&d->bd_sel);
513 	rel_mplock();
514 	/* XXX */
515 	d->bd_sel.si_pid = 0;
516 }
517 
518 static void
519 bpf_timed_out(void *arg)
520 {
521 	struct bpf_d *d = (struct bpf_d *)arg;
522 
523 	crit_enter();
524 	if (d->bd_state == BPF_WAITING) {
525 		d->bd_state = BPF_TIMED_OUT;
526 		if (d->bd_slen != 0)
527 			bpf_wakeup(d);
528 	}
529 	crit_exit();
530 }
531 
532 static void
533 bpf_output_dispatch(struct netmsg *nmsg)
534 {
535 	struct netmsg_bpf_output *bmsg = (struct netmsg_bpf_output *)nmsg;
536 	struct ifnet *ifp = bmsg->nm_ifp;
537 	int error;
538 
539 	/*
540 	 * The driver frees the mbuf.
541 	 */
542 	error = ifp->if_output(ifp, bmsg->nm_mbuf, bmsg->nm_dst, NULL);
543 	lwkt_replymsg(&nmsg->nm_lmsg, error);
544 }
545 
546 static int
547 bpfwrite(struct dev_write_args *ap)
548 {
549 	cdev_t dev = ap->a_head.a_dev;
550 	struct bpf_d *d = dev->si_drv1;
551 	struct ifnet *ifp;
552 	struct mbuf *m;
553 	int error;
554 	struct sockaddr dst;
555 	int datlen;
556 	struct netmsg_bpf_output bmsg;
557 
558 	if (d->bd_bif == NULL)
559 		return(ENXIO);
560 
561 	ifp = d->bd_bif->bif_ifp;
562 
563 	if (ap->a_uio->uio_resid == 0)
564 		return(0);
565 
566 	error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
567 			   &dst, &datlen, d->bd_wfilter);
568 	if (error)
569 		return(error);
570 
571 	if (datlen > ifp->if_mtu) {
572 		m_freem(m);
573 		return(EMSGSIZE);
574 	}
575 
576 	if (d->bd_hdrcmplt)
577 		dst.sa_family = pseudo_AF_HDRCMPLT;
578 
579 	netmsg_init(&bmsg.nm_netmsg, &curthread->td_msgport, MSGF_MPSAFE,
580 		    bpf_output_dispatch);
581 	bmsg.nm_mbuf = m;
582 	bmsg.nm_ifp = ifp;
583 	bmsg.nm_dst = &dst;
584 
585 	return lwkt_domsg(cpu_portfn(0), &bmsg.nm_netmsg.nm_lmsg, 0);
586 }
587 
588 /*
589  * Reset a descriptor by flushing its packet buffer and clearing the
590  * receive and drop counts.  Should be called at splimp.
591  */
592 static void
593 bpf_resetd(struct bpf_d *d)
594 {
595 	if (d->bd_hbuf) {
596 		/* Free the hold buffer. */
597 		d->bd_fbuf = d->bd_hbuf;
598 		d->bd_hbuf = NULL;
599 	}
600 	d->bd_slen = 0;
601 	d->bd_hlen = 0;
602 	d->bd_rcount = 0;
603 	d->bd_dcount = 0;
604 }
605 
606 /*
607  *  FIONREAD		Check for read packet available.
608  *  SIOCGIFADDR		Get interface address - convenient hook to driver.
609  *  BIOCGBLEN		Get buffer len [for read()].
610  *  BIOCSETF		Set ethernet read filter.
611  *  BIOCSETWF		Set ethernet write filter.
612  *  BIOCFLUSH		Flush read packet buffer.
613  *  BIOCPROMISC		Put interface into promiscuous mode.
614  *  BIOCGDLT		Get link layer type.
615  *  BIOCGETIF		Get interface name.
616  *  BIOCSETIF		Set interface.
617  *  BIOCSRTIMEOUT	Set read timeout.
618  *  BIOCGRTIMEOUT	Get read timeout.
619  *  BIOCGSTATS		Get packet stats.
620  *  BIOCIMMEDIATE	Set immediate mode.
621  *  BIOCVERSION		Get filter language version.
622  *  BIOCGHDRCMPLT	Get "header already complete" flag
623  *  BIOCSHDRCMPLT	Set "header already complete" flag
624  *  BIOCGSEESENT	Get "see packets sent" flag
625  *  BIOCSSEESENT	Set "see packets sent" flag
626  *  BIOCLOCK		Set "locked" flag
627  */
628 /* ARGSUSED */
629 static int
630 bpfioctl(struct dev_ioctl_args *ap)
631 {
632 	cdev_t dev = ap->a_head.a_dev;
633 	struct bpf_d *d = dev->si_drv1;
634 	int error = 0;
635 
636 	crit_enter();
637 	if (d->bd_state == BPF_WAITING)
638 		callout_stop(&d->bd_callout);
639 	d->bd_state = BPF_IDLE;
640 	crit_exit();
641 
642 	if (d->bd_locked == 1) {
643 		switch (ap->a_cmd) {
644 		case BIOCGBLEN:
645 		case BIOCFLUSH:
646 		case BIOCGDLT:
647 		case BIOCGDLTLIST:
648 		case BIOCGETIF:
649 		case BIOCGRTIMEOUT:
650 		case BIOCGSTATS:
651 		case BIOCVERSION:
652 		case BIOCGRSIG:
653 		case BIOCGHDRCMPLT:
654 		case FIONREAD:
655 		case BIOCLOCK:
656 		case BIOCSRTIMEOUT:
657 		case BIOCIMMEDIATE:
658 		case TIOCGPGRP:
659 			break;
660 		default:
661 			return (EPERM);
662 		}
663 	}
664 	switch (ap->a_cmd) {
665 	default:
666 		error = EINVAL;
667 		break;
668 
669 	/*
670 	 * Check for read packet available.
671 	 */
672 	case FIONREAD:
673 		{
674 			int n;
675 
676 			crit_enter();
677 			n = d->bd_slen;
678 			if (d->bd_hbuf)
679 				n += d->bd_hlen;
680 			crit_exit();
681 
682 			*(int *)ap->a_data = n;
683 			break;
684 		}
685 
686 	case SIOCGIFADDR:
687 		{
688 			struct ifnet *ifp;
689 
690 			if (d->bd_bif == NULL) {
691 				error = EINVAL;
692 			} else {
693 				ifp = d->bd_bif->bif_ifp;
694 				ifnet_serialize_all(ifp);
695 				error = ifp->if_ioctl(ifp, ap->a_cmd,
696 						      ap->a_data, ap->a_cred);
697 				ifnet_deserialize_all(ifp);
698 			}
699 			break;
700 		}
701 
702 	/*
703 	 * Get buffer len [for read()].
704 	 */
705 	case BIOCGBLEN:
706 		*(u_int *)ap->a_data = d->bd_bufsize;
707 		break;
708 
709 	/*
710 	 * Set buffer length.
711 	 */
712 	case BIOCSBLEN:
713 		if (d->bd_bif != NULL) {
714 			error = EINVAL;
715 		} else {
716 			u_int size = *(u_int *)ap->a_data;
717 
718 			if (size > bpf_maxbufsize)
719 				*(u_int *)ap->a_data = size = bpf_maxbufsize;
720 			else if (size < BPF_MINBUFSIZE)
721 				*(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
722 			d->bd_bufsize = size;
723 		}
724 		break;
725 
726 	/*
727 	 * Set link layer read filter.
728 	 */
729 	case BIOCSETF:
730 	case BIOCSETWF:
731 		error = bpf_setf(d, (struct bpf_program *)ap->a_data,
732 			ap->a_cmd);
733 		break;
734 
735 	/*
736 	 * Flush read packet buffer.
737 	 */
738 	case BIOCFLUSH:
739 		crit_enter();
740 		bpf_resetd(d);
741 		crit_exit();
742 		break;
743 
744 	/*
745 	 * Put interface into promiscuous mode.
746 	 */
747 	case BIOCPROMISC:
748 		if (d->bd_bif == NULL) {
749 			/*
750 			 * No interface attached yet.
751 			 */
752 			error = EINVAL;
753 			break;
754 		}
755 		crit_enter();
756 		if (d->bd_promisc == 0) {
757 			error = ifpromisc(d->bd_bif->bif_ifp, 1);
758 			if (error == 0)
759 				d->bd_promisc = 1;
760 		}
761 		crit_exit();
762 		break;
763 
764 	/*
765 	 * Get device parameters.
766 	 */
767 	case BIOCGDLT:
768 		if (d->bd_bif == NULL)
769 			error = EINVAL;
770 		else
771 			*(u_int *)ap->a_data = d->bd_bif->bif_dlt;
772 		break;
773 
774 	/*
775 	 * Get a list of supported data link types.
776 	 */
777 	case BIOCGDLTLIST:
778 		if (d->bd_bif == NULL) {
779 			error = EINVAL;
780 		} else {
781 			error = bpf_getdltlist(d,
782 				(struct bpf_dltlist *)ap->a_data);
783 		}
784 		break;
785 
786 	/*
787 	 * Set data link type.
788 	 */
789 	case BIOCSDLT:
790 		if (d->bd_bif == NULL)
791 			error = EINVAL;
792 		else
793 			error = bpf_setdlt(d, *(u_int *)ap->a_data);
794 		break;
795 
796 	/*
797 	 * Get interface name.
798 	 */
799 	case BIOCGETIF:
800 		if (d->bd_bif == NULL) {
801 			error = EINVAL;
802 		} else {
803 			struct ifnet *const ifp = d->bd_bif->bif_ifp;
804 			struct ifreq *const ifr = (struct ifreq *)ap->a_data;
805 
806 			strlcpy(ifr->ifr_name, ifp->if_xname,
807 				sizeof ifr->ifr_name);
808 		}
809 		break;
810 
811 	/*
812 	 * Set interface.
813 	 */
814 	case BIOCSETIF:
815 		error = bpf_setif(d, (struct ifreq *)ap->a_data);
816 		break;
817 
818 	/*
819 	 * Set read timeout.
820 	 */
821 	case BIOCSRTIMEOUT:
822 		{
823 			struct timeval *tv = (struct timeval *)ap->a_data;
824 
825 			/*
826 			 * Subtract 1 tick from tvtohz() since this isn't
827 			 * a one-shot timer.
828 			 */
829 			if ((error = itimerfix(tv)) == 0)
830 				d->bd_rtout = tvtohz_low(tv);
831 			break;
832 		}
833 
834 	/*
835 	 * Get read timeout.
836 	 */
837 	case BIOCGRTIMEOUT:
838 		{
839 			struct timeval *tv = (struct timeval *)ap->a_data;
840 
841 			tv->tv_sec = d->bd_rtout / hz;
842 			tv->tv_usec = (d->bd_rtout % hz) * tick;
843 			break;
844 		}
845 
846 	/*
847 	 * Get packet stats.
848 	 */
849 	case BIOCGSTATS:
850 		{
851 			struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
852 
853 			bs->bs_recv = d->bd_rcount;
854 			bs->bs_drop = d->bd_dcount;
855 			break;
856 		}
857 
858 	/*
859 	 * Set immediate mode.
860 	 */
861 	case BIOCIMMEDIATE:
862 		d->bd_immediate = *(u_int *)ap->a_data;
863 		break;
864 
865 	case BIOCVERSION:
866 		{
867 			struct bpf_version *bv = (struct bpf_version *)ap->a_data;
868 
869 			bv->bv_major = BPF_MAJOR_VERSION;
870 			bv->bv_minor = BPF_MINOR_VERSION;
871 			break;
872 		}
873 
874 	/*
875 	 * Get "header already complete" flag
876 	 */
877 	case BIOCGHDRCMPLT:
878 		*(u_int *)ap->a_data = d->bd_hdrcmplt;
879 		break;
880 
881 	/*
882 	 * Set "header already complete" flag
883 	 */
884 	case BIOCSHDRCMPLT:
885 		d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
886 		break;
887 
888 	/*
889 	 * Get "see sent packets" flag
890 	 */
891 	case BIOCGSEESENT:
892 		*(u_int *)ap->a_data = d->bd_seesent;
893 		break;
894 
895 	/*
896 	 * Set "see sent packets" flag
897 	 */
898 	case BIOCSSEESENT:
899 		d->bd_seesent = *(u_int *)ap->a_data;
900 		break;
901 
902 	case FIOASYNC:		/* Send signal on receive packets */
903 		d->bd_async = *(int *)ap->a_data;
904 		break;
905 
906 	case FIOSETOWN:
907 		error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
908 		break;
909 
910 	case FIOGETOWN:
911 		*(int *)ap->a_data = fgetown(d->bd_sigio);
912 		break;
913 
914 	/* This is deprecated, FIOSETOWN should be used instead. */
915 	case TIOCSPGRP:
916 		error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
917 		break;
918 
919 	/* This is deprecated, FIOGETOWN should be used instead. */
920 	case TIOCGPGRP:
921 		*(int *)ap->a_data = -fgetown(d->bd_sigio);
922 		break;
923 
924 	case BIOCSRSIG:		/* Set receive signal */
925 		{
926 			u_int sig;
927 
928 			sig = *(u_int *)ap->a_data;
929 
930 			if (sig >= NSIG)
931 				error = EINVAL;
932 			else
933 				d->bd_sig = sig;
934 			break;
935 		}
936 	case BIOCGRSIG:
937 		*(u_int *)ap->a_data = d->bd_sig;
938 		break;
939 	case BIOCLOCK:
940 		d->bd_locked = 1;
941 		break;
942 	}
943 	return(error);
944 }
945 
946 /*
947  * Set d's packet filter program to fp.  If this file already has a filter,
948  * free it and replace it.  Returns EINVAL for bogus requests.
949  */
950 static int
951 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
952 {
953 	struct bpf_insn *fcode, *old;
954 	u_int wfilter, flen, size;
955 
956 	if (cmd == BIOCSETWF) {
957 		old = d->bd_wfilter;
958 		wfilter = 1;
959 	} else {
960 		wfilter = 0;
961 		old = d->bd_rfilter;
962 	}
963 	if (fp->bf_insns == NULL) {
964 		if (fp->bf_len != 0)
965 			return(EINVAL);
966 		crit_enter();
967 		if (wfilter)
968 			d->bd_wfilter = NULL;
969 		else
970 			d->bd_rfilter = NULL;
971 		bpf_resetd(d);
972 		crit_exit();
973 		if (old != NULL)
974 			kfree(old, M_BPF);
975 		return(0);
976 	}
977 	flen = fp->bf_len;
978 	if (flen > BPF_MAXINSNS)
979 		return(EINVAL);
980 
981 	size = flen * sizeof *fp->bf_insns;
982 	fcode = (struct bpf_insn *)kmalloc(size, M_BPF, M_WAITOK);
983 	if (copyin(fp->bf_insns, fcode, size) == 0 &&
984 	    bpf_validate(fcode, (int)flen)) {
985 		crit_enter();
986 		if (wfilter)
987 			d->bd_wfilter = fcode;
988 		else
989 			d->bd_rfilter = fcode;
990 		bpf_resetd(d);
991 		crit_exit();
992 		if (old != NULL)
993 			kfree(old, M_BPF);
994 
995 		return(0);
996 	}
997 	kfree(fcode, M_BPF);
998 	return(EINVAL);
999 }
1000 
1001 /*
1002  * Detach a file from its current interface (if attached at all) and attach
1003  * to the interface indicated by the name stored in ifr.
1004  * Return an errno or 0.
1005  */
1006 static int
1007 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
1008 {
1009 	struct bpf_if *bp;
1010 	int error;
1011 	struct ifnet *theywant;
1012 
1013 	theywant = ifunit(ifr->ifr_name);
1014 	if (theywant == NULL)
1015 		return(ENXIO);
1016 
1017 	/*
1018 	 * Look through attached interfaces for the named one.
1019 	 */
1020 	for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1021 		struct ifnet *ifp = bp->bif_ifp;
1022 
1023 		if (ifp == NULL || ifp != theywant)
1024 			continue;
1025 		/* skip additional entry */
1026 		if (bp->bif_driverp != &ifp->if_bpf)
1027 			continue;
1028 		/*
1029 		 * We found the requested interface.
1030 		 * If it's not up, return an error.
1031 		 * Allocate the packet buffers if we need to.
1032 		 * If we're already attached to requested interface,
1033 		 * just flush the buffer.
1034 		 */
1035 		if (!(ifp->if_flags & IFF_UP))
1036 			return(ENETDOWN);
1037 
1038 		if (d->bd_sbuf == NULL) {
1039 			error = bpf_allocbufs(d);
1040 			if (error != 0)
1041 				return(error);
1042 		}
1043 		crit_enter();
1044 		if (bp != d->bd_bif) {
1045 			if (d->bd_bif != NULL) {
1046 				/*
1047 				 * Detach if attached to something else.
1048 				 */
1049 				bpf_detachd(d);
1050 			}
1051 
1052 			bpf_attachd(d, bp);
1053 		}
1054 		bpf_resetd(d);
1055 		crit_exit();
1056 		return(0);
1057 	}
1058 
1059 	/* Not found. */
1060 	return(ENXIO);
1061 }
1062 
1063 /*
1064  * Support for select() and poll() system calls
1065  *
1066  * Return true iff the specific operation will not block indefinitely.
1067  * Otherwise, return false but make a note that a selwakeup() must be done.
1068  */
1069 static int
1070 bpfpoll(struct dev_poll_args *ap)
1071 {
1072 	cdev_t dev = ap->a_head.a_dev;
1073 	struct bpf_d *d;
1074 	int revents;
1075 
1076 	d = dev->si_drv1;
1077 	if (d->bd_bif == NULL)
1078 		return(ENXIO);
1079 
1080 	revents = ap->a_events & (POLLOUT | POLLWRNORM);
1081 	crit_enter();
1082 	if (ap->a_events & (POLLIN | POLLRDNORM)) {
1083 		/*
1084 		 * An imitation of the FIONREAD ioctl code.
1085 		 * XXX not quite.  An exact imitation:
1086 		 *	if (d->b_slen != 0 ||
1087 		 *	    (d->bd_hbuf != NULL && d->bd_hlen != 0)
1088 		 */
1089 		if (d->bd_hlen != 0 ||
1090 		    ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1091 		    d->bd_slen != 0)) {
1092 			revents |= ap->a_events & (POLLIN | POLLRDNORM);
1093 		} else {
1094 			selrecord(curthread, &d->bd_sel);
1095 			/* Start the read timeout if necessary. */
1096 			if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1097 				callout_reset(&d->bd_callout, d->bd_rtout,
1098 				    bpf_timed_out, d);
1099 				d->bd_state = BPF_WAITING;
1100 			}
1101 		}
1102 	}
1103 	crit_exit();
1104 	ap->a_events = revents;
1105 	return(0);
1106 }
1107 
1108 /*
1109  * Process the packet pkt of length pktlen.  The packet is parsed
1110  * by each listener's filter, and if accepted, stashed into the
1111  * corresponding buffer.
1112  */
1113 void
1114 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1115 {
1116 	struct bpf_d *d;
1117 	struct timeval tv;
1118 	int gottime = 0;
1119 	u_int slen;
1120 
1121 	get_mplock();
1122 
1123 	/* Re-check */
1124 	if (bp == NULL) {
1125 		rel_mplock();
1126 		return;
1127 	}
1128 
1129 	/*
1130 	 * Note that the ipl does not have to be raised at this point.
1131 	 * The only problem that could arise here is that if two different
1132 	 * interfaces shared any data.  This is not the case.
1133 	 */
1134 	SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1135 		++d->bd_rcount;
1136 		slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
1137 		if (slen != 0) {
1138 			if (!gottime) {
1139 				microtime(&tv);
1140 				gottime = 1;
1141 			}
1142 			catchpacket(d, pkt, pktlen, slen, ovbcopy, &tv);
1143 		}
1144 	}
1145 
1146 	rel_mplock();
1147 }
1148 
1149 /*
1150  * Copy data from an mbuf chain into a buffer.  This code is derived
1151  * from m_copydata in sys/uipc_mbuf.c.
1152  */
1153 static void
1154 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1155 {
1156 	const struct mbuf *m;
1157 	u_int count;
1158 	u_char *dst;
1159 
1160 	m = src_arg;
1161 	dst = dst_arg;
1162 	while (len > 0) {
1163 		if (m == NULL)
1164 			panic("bpf_mcopy");
1165 		count = min(m->m_len, len);
1166 		bcopy(mtod(m, void *), dst, count);
1167 		m = m->m_next;
1168 		dst += count;
1169 		len -= count;
1170 	}
1171 }
1172 
1173 /*
1174  * Process the packet in the mbuf chain m.  The packet is parsed by each
1175  * listener's filter, and if accepted, stashed into the corresponding
1176  * buffer.
1177  */
1178 void
1179 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1180 {
1181 	struct bpf_d *d;
1182 	u_int pktlen, slen;
1183 	struct timeval tv;
1184 	int gottime = 0;
1185 
1186 	get_mplock();
1187 
1188 	/* Re-check */
1189 	if (bp == NULL) {
1190 		rel_mplock();
1191 		return;
1192 	}
1193 
1194 	/* Don't compute pktlen, if no descriptor is attached. */
1195 	if (SLIST_EMPTY(&bp->bif_dlist)) {
1196 		rel_mplock();
1197 		return;
1198 	}
1199 
1200 	pktlen = m_lengthm(m, NULL);
1201 
1202 	SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1203 		if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1204 			continue;
1205 		++d->bd_rcount;
1206 		slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
1207 		if (slen != 0) {
1208 			if (!gottime) {
1209 				microtime(&tv);
1210 				gottime = 1;
1211 			}
1212 			catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy,
1213 				    &tv);
1214 		}
1215 	}
1216 
1217 	rel_mplock();
1218 }
1219 
1220 void
1221 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1222 {
1223 	u_int family4;
1224 
1225 	KKASSERT(family != AF_UNSPEC);
1226 
1227 	family4 = (u_int)family;
1228 	bpf_ptap(bp, m, &family4, sizeof(family4));
1229 }
1230 
1231 /*
1232  * Process the packet in the mbuf chain m with the header in m prepended.
1233  * The packet is parsed by each listener's filter, and if accepted,
1234  * stashed into the corresponding buffer.
1235  */
1236 void
1237 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1238 {
1239 	struct mbuf mb;
1240 
1241 	/*
1242 	 * Craft on-stack mbuf suitable for passing to bpf_mtap.
1243 	 * Note that we cut corners here; we only setup what's
1244 	 * absolutely needed--this mbuf should never go anywhere else.
1245 	 */
1246 	mb.m_next = m;
1247 	mb.m_data = __DECONST(void *, data); /* LINTED */
1248 	mb.m_len = dlen;
1249 	mb.m_pkthdr.rcvif = m->m_pkthdr.rcvif;
1250 
1251 	bpf_mtap(bp, &mb);
1252 }
1253 
1254 /*
1255  * Move the packet data from interface memory (pkt) into the
1256  * store buffer.  Return 1 if it's time to wakeup a listener (buffer full),
1257  * otherwise 0.  "copy" is the routine called to do the actual data
1258  * transfer.  bcopy is passed in to copy contiguous chunks, while
1259  * bpf_mcopy is passed in to copy mbuf chains.  In the latter case,
1260  * pkt is really an mbuf.
1261  */
1262 static void
1263 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1264 	    void (*cpfn)(const void *, void *, size_t),
1265 	    const struct timeval *tv)
1266 {
1267 	struct bpf_hdr *hp;
1268 	int totlen, curlen;
1269 	int hdrlen = d->bd_bif->bif_hdrlen;
1270 	/*
1271 	 * Figure out how many bytes to move.  If the packet is
1272 	 * greater or equal to the snapshot length, transfer that
1273 	 * much.  Otherwise, transfer the whole packet (unless
1274 	 * we hit the buffer size limit).
1275 	 */
1276 	totlen = hdrlen + min(snaplen, pktlen);
1277 	if (totlen > d->bd_bufsize)
1278 		totlen = d->bd_bufsize;
1279 
1280 	/*
1281 	 * Round up the end of the previous packet to the next longword.
1282 	 */
1283 	curlen = BPF_WORDALIGN(d->bd_slen);
1284 	if (curlen + totlen > d->bd_bufsize) {
1285 		/*
1286 		 * This packet will overflow the storage buffer.
1287 		 * Rotate the buffers if we can, then wakeup any
1288 		 * pending reads.
1289 		 */
1290 		if (d->bd_fbuf == NULL) {
1291 			/*
1292 			 * We haven't completed the previous read yet,
1293 			 * so drop the packet.
1294 			 */
1295 			++d->bd_dcount;
1296 			return;
1297 		}
1298 		ROTATE_BUFFERS(d);
1299 		bpf_wakeup(d);
1300 		curlen = 0;
1301 	} else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) {
1302 		/*
1303 		 * Immediate mode is set, or the read timeout has
1304 		 * already expired during a select call.  A packet
1305 		 * arrived, so the reader should be woken up.
1306 		 */
1307 		bpf_wakeup(d);
1308 	}
1309 
1310 	/*
1311 	 * Append the bpf header.
1312 	 */
1313 	hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1314 	hp->bh_tstamp = *tv;
1315 	hp->bh_datalen = pktlen;
1316 	hp->bh_hdrlen = hdrlen;
1317 	/*
1318 	 * Copy the packet data into the store buffer and update its length.
1319 	 */
1320 	(*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1321 	d->bd_slen = curlen + totlen;
1322 }
1323 
1324 /*
1325  * Initialize all nonzero fields of a descriptor.
1326  */
1327 static int
1328 bpf_allocbufs(struct bpf_d *d)
1329 {
1330 	d->bd_fbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1331 	d->bd_sbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1332 	d->bd_slen = 0;
1333 	d->bd_hlen = 0;
1334 	return(0);
1335 }
1336 
1337 /*
1338  * Free buffers and packet filter program currently in use by a descriptor.
1339  * Called on close.
1340  */
1341 static void
1342 bpf_freed(struct bpf_d *d)
1343 {
1344 	/*
1345 	 * We don't need to lock out interrupts since this descriptor has
1346 	 * been detached from its interface and it yet hasn't been marked
1347 	 * free.
1348 	 */
1349 	if (d->bd_sbuf != NULL) {
1350 		kfree(d->bd_sbuf, M_BPF);
1351 		if (d->bd_hbuf != NULL)
1352 			kfree(d->bd_hbuf, M_BPF);
1353 		if (d->bd_fbuf != NULL)
1354 			kfree(d->bd_fbuf, M_BPF);
1355 	}
1356 	if (d->bd_rfilter)
1357 		kfree(d->bd_rfilter, M_BPF);
1358 	if (d->bd_wfilter)
1359 		kfree(d->bd_wfilter, M_BPF);
1360 }
1361 
1362 /*
1363  * Attach an interface to bpf.  ifp is a pointer to the structure
1364  * defining the interface to be attached, dlt is the link layer type,
1365  * and hdrlen is the fixed size of the link header (variable length
1366  * headers are not yet supported).
1367  */
1368 void
1369 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1370 {
1371 	bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1372 }
1373 
1374 void
1375 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1376 {
1377 	struct bpf_if *bp;
1378 
1379 	bp = kmalloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1380 
1381 	SLIST_INIT(&bp->bif_dlist);
1382 	bp->bif_ifp = ifp;
1383 	bp->bif_dlt = dlt;
1384 	bp->bif_driverp = driverp;
1385 	*bp->bif_driverp = NULL;
1386 
1387 	bp->bif_next = bpf_iflist;
1388 	bpf_iflist = bp;
1389 
1390 	/*
1391 	 * Compute the length of the bpf header.  This is not necessarily
1392 	 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1393 	 * that the network layer header begins on a longword boundary (for
1394 	 * performance reasons and to alleviate alignment restrictions).
1395 	 */
1396 	bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1397 
1398 	if (bootverbose)
1399 		if_printf(ifp, "bpf attached\n");
1400 }
1401 
1402 /*
1403  * Detach bpf from an interface.  This involves detaching each descriptor
1404  * associated with the interface, and leaving bd_bif NULL.  Notify each
1405  * descriptor as it's detached so that any sleepers wake up and get
1406  * ENXIO.
1407  */
1408 void
1409 bpfdetach(struct ifnet *ifp)
1410 {
1411 	struct bpf_if *bp, *bp_prev;
1412 	struct bpf_d *d;
1413 
1414 	crit_enter();
1415 
1416 	/* Locate BPF interface information */
1417 	bp_prev = NULL;
1418 	for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1419 		if (ifp == bp->bif_ifp)
1420 			break;
1421 		bp_prev = bp;
1422 	}
1423 
1424 	/* Interface wasn't attached */
1425 	if (bp->bif_ifp == NULL) {
1426 		crit_exit();
1427 		kprintf("bpfdetach: %s was not attached\n", ifp->if_xname);
1428 		return;
1429 	}
1430 
1431 	while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1432 		bpf_detachd(d);
1433 		bpf_wakeup(d);
1434 	}
1435 
1436 	if (bp_prev != NULL)
1437 		bp_prev->bif_next = bp->bif_next;
1438 	else
1439 		bpf_iflist = bp->bif_next;
1440 
1441 	kfree(bp, M_BPF);
1442 
1443 	crit_exit();
1444 }
1445 
1446 /*
1447  * Get a list of available data link type of the interface.
1448  */
1449 static int
1450 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1451 {
1452 	int n, error;
1453 	struct ifnet *ifp;
1454 	struct bpf_if *bp;
1455 
1456 	ifp = d->bd_bif->bif_ifp;
1457 	n = 0;
1458 	error = 0;
1459 	for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1460 		if (bp->bif_ifp != ifp)
1461 			continue;
1462 		if (bfl->bfl_list != NULL) {
1463 			if (n >= bfl->bfl_len) {
1464 				return (ENOMEM);
1465 			}
1466 			error = copyout(&bp->bif_dlt,
1467 			    bfl->bfl_list + n, sizeof(u_int));
1468 		}
1469 		n++;
1470 	}
1471 	bfl->bfl_len = n;
1472 	return(error);
1473 }
1474 
1475 /*
1476  * Set the data link type of a BPF instance.
1477  */
1478 static int
1479 bpf_setdlt(struct bpf_d *d, u_int dlt)
1480 {
1481 	int error, opromisc;
1482 	struct ifnet *ifp;
1483 	struct bpf_if *bp;
1484 
1485 	if (d->bd_bif->bif_dlt == dlt)
1486 		return (0);
1487 	ifp = d->bd_bif->bif_ifp;
1488 	for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1489 		if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1490 			break;
1491 	}
1492 	if (bp != NULL) {
1493 		opromisc = d->bd_promisc;
1494 		crit_enter();
1495 		bpf_detachd(d);
1496 		bpf_attachd(d, bp);
1497 		bpf_resetd(d);
1498 		if (opromisc) {
1499 			error = ifpromisc(bp->bif_ifp, 1);
1500 			if (error) {
1501 				if_printf(bp->bif_ifp,
1502 					"bpf_setdlt: ifpromisc failed (%d)\n",
1503 					error);
1504 			} else {
1505 				d->bd_promisc = 1;
1506 			}
1507 		}
1508 		crit_exit();
1509 	}
1510 	return(bp == NULL ? EINVAL : 0);
1511 }
1512 
1513 static void
1514 bpf_drvinit(void *unused)
1515 {
1516 	int i;
1517 
1518 	make_autoclone_dev(&bpf_ops, &DEVFS_CLONE_BITMAP(bpf),
1519 		bpfclone, 0, 0, 0600, "bpf");
1520 	for (i = 0; i < BPF_PREALLOCATED_UNITS; i++) {
1521 		make_dev(&bpf_ops, i, 0, 0, 0600, "bpf%d", i);
1522 		devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(bpf), i);
1523 	}
1524 }
1525 
1526 static void
1527 bpf_drvuninit(void *unused)
1528 {
1529 	devfs_clone_handler_del("bpf");
1530 	dev_ops_remove_all(&bpf_ops);
1531 	devfs_clone_bitmap_uninit(&DEVFS_CLONE_BITMAP(bpf));
1532 }
1533 
1534 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1535 SYSUNINIT(bpfdev, SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvuninit, NULL);
1536 
1537 #else /* !BPF */
1538 /*
1539  * NOP stubs to allow bpf-using drivers to load and function.
1540  *
1541  * A 'better' implementation would allow the core bpf functionality
1542  * to be loaded at runtime.
1543  */
1544 
1545 void
1546 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1547 {
1548 }
1549 
1550 void
1551 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1552 {
1553 }
1554 
1555 void
1556 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1557 {
1558 }
1559 
1560 void
1561 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1562 {
1563 }
1564 
1565 void
1566 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1567 {
1568 }
1569 
1570 void
1571 bpfdetach(struct ifnet *ifp)
1572 {
1573 }
1574 
1575 u_int
1576 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1577 {
1578 	return -1;	/* "no filter" behaviour */
1579 }
1580 
1581 #endif /* !BPF */
1582