xref: /freebsd/sys/net/bpf.c (revision 6c74ff0ea6eb5eb3a21d05486740c9488721a8b5)
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  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *      @(#)bpf.c	8.4 (Berkeley) 1/9/95
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_bpf.h"
41 #include "opt_compat.h"
42 #include "opt_netgraph.h"
43 
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/lock.h>
47 #include <sys/rwlock.h>
48 #include <sys/systm.h>
49 #include <sys/conf.h>
50 #include <sys/fcntl.h>
51 #include <sys/jail.h>
52 #include <sys/malloc.h>
53 #include <sys/mbuf.h>
54 #include <sys/time.h>
55 #include <sys/priv.h>
56 #include <sys/proc.h>
57 #include <sys/signalvar.h>
58 #include <sys/filio.h>
59 #include <sys/sockio.h>
60 #include <sys/ttycom.h>
61 #include <sys/uio.h>
62 
63 #include <sys/event.h>
64 #include <sys/file.h>
65 #include <sys/poll.h>
66 #include <sys/proc.h>
67 
68 #include <sys/socket.h>
69 
70 #include <net/if.h>
71 #define	BPF_INTERNAL
72 #include <net/bpf.h>
73 #include <net/bpf_buffer.h>
74 #ifdef BPF_JITTER
75 #include <net/bpf_jitter.h>
76 #endif
77 #include <net/bpf_zerocopy.h>
78 #include <net/bpfdesc.h>
79 #include <net/vnet.h>
80 
81 #include <netinet/in.h>
82 #include <netinet/if_ether.h>
83 #include <sys/kernel.h>
84 #include <sys/sysctl.h>
85 
86 #include <net80211/ieee80211_freebsd.h>
87 
88 #include <security/mac/mac_framework.h>
89 
90 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
91 
92 #if defined(DEV_BPF) || defined(NETGRAPH_BPF)
93 
94 #define PRINET  26			/* interruptible */
95 
96 #define	SIZEOF_BPF_HDR(type)	\
97     (offsetof(type, bh_hdrlen) + sizeof(((type *)0)->bh_hdrlen))
98 
99 #ifdef COMPAT_FREEBSD32
100 #include <sys/mount.h>
101 #include <compat/freebsd32/freebsd32.h>
102 #define BPF_ALIGNMENT32 sizeof(int32_t)
103 #define BPF_WORDALIGN32(x) (((x)+(BPF_ALIGNMENT32-1))&~(BPF_ALIGNMENT32-1))
104 
105 #ifndef BURN_BRIDGES
106 /*
107  * 32-bit version of structure prepended to each packet.  We use this header
108  * instead of the standard one for 32-bit streams.  We mark the a stream as
109  * 32-bit the first time we see a 32-bit compat ioctl request.
110  */
111 struct bpf_hdr32 {
112 	struct timeval32 bh_tstamp;	/* time stamp */
113 	uint32_t	bh_caplen;	/* length of captured portion */
114 	uint32_t	bh_datalen;	/* original length of packet */
115 	uint16_t	bh_hdrlen;	/* length of bpf header (this struct
116 					   plus alignment padding) */
117 };
118 #endif
119 
120 struct bpf_program32 {
121 	u_int bf_len;
122 	uint32_t bf_insns;
123 };
124 
125 struct bpf_dltlist32 {
126 	u_int	bfl_len;
127 	u_int	bfl_list;
128 };
129 
130 #define	BIOCSETF32	_IOW('B', 103, struct bpf_program32)
131 #define	BIOCSRTIMEOUT32	_IOW('B', 109, struct timeval32)
132 #define	BIOCGRTIMEOUT32	_IOR('B', 110, struct timeval32)
133 #define	BIOCGDLTLIST32	_IOWR('B', 121, struct bpf_dltlist32)
134 #define	BIOCSETWF32	_IOW('B', 123, struct bpf_program32)
135 #define	BIOCSETFNR32	_IOW('B', 130, struct bpf_program32)
136 #endif
137 
138 /*
139  * bpf_iflist is a list of BPF interface structures, each corresponding to a
140  * specific DLT.  The same network interface might have several BPF interface
141  * structures registered by different layers in the stack (i.e., 802.11
142  * frames, ethernet frames, etc).
143  */
144 static LIST_HEAD(, bpf_if)	bpf_iflist;
145 static struct mtx	bpf_mtx;		/* bpf global lock */
146 static int		bpf_bpfd_cnt;
147 
148 static void	bpf_attachd(struct bpf_d *, struct bpf_if *);
149 static void	bpf_detachd(struct bpf_d *);
150 static void	bpf_detachd_locked(struct bpf_d *);
151 static void	bpf_freed(struct bpf_d *);
152 static int	bpf_movein(struct uio *, int, struct ifnet *, struct mbuf **,
153 		    struct sockaddr *, int *, struct bpf_insn *);
154 static int	bpf_setif(struct bpf_d *, struct ifreq *);
155 static void	bpf_timed_out(void *);
156 static __inline void
157 		bpf_wakeup(struct bpf_d *);
158 static void	catchpacket(struct bpf_d *, u_char *, u_int, u_int,
159 		    void (*)(struct bpf_d *, caddr_t, u_int, void *, u_int),
160 		    struct bintime *);
161 static void	reset_d(struct bpf_d *);
162 static int	 bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
163 static int	bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
164 static int	bpf_setdlt(struct bpf_d *, u_int);
165 static void	filt_bpfdetach(struct knote *);
166 static int	filt_bpfread(struct knote *, long);
167 static void	bpf_drvinit(void *);
168 static int	bpf_stats_sysctl(SYSCTL_HANDLER_ARGS);
169 
170 SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl");
171 int bpf_maxinsns = BPF_MAXINSNS;
172 SYSCTL_INT(_net_bpf, OID_AUTO, maxinsns, CTLFLAG_RW,
173     &bpf_maxinsns, 0, "Maximum bpf program instructions");
174 static int bpf_zerocopy_enable = 0;
175 SYSCTL_INT(_net_bpf, OID_AUTO, zerocopy_enable, CTLFLAG_RW,
176     &bpf_zerocopy_enable, 0, "Enable new zero-copy BPF buffer sessions");
177 static SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_MPSAFE | CTLFLAG_RW,
178     bpf_stats_sysctl, "bpf statistics portal");
179 
180 static VNET_DEFINE(int, bpf_optimize_writers) = 0;
181 #define	V_bpf_optimize_writers VNET(bpf_optimize_writers)
182 SYSCTL_VNET_INT(_net_bpf, OID_AUTO, optimize_writers,
183     CTLFLAG_RW, &VNET_NAME(bpf_optimize_writers), 0,
184     "Do not send packets until BPF program is set");
185 
186 static	d_open_t	bpfopen;
187 static	d_read_t	bpfread;
188 static	d_write_t	bpfwrite;
189 static	d_ioctl_t	bpfioctl;
190 static	d_poll_t	bpfpoll;
191 static	d_kqfilter_t	bpfkqfilter;
192 
193 static struct cdevsw bpf_cdevsw = {
194 	.d_version =	D_VERSION,
195 	.d_open =	bpfopen,
196 	.d_read =	bpfread,
197 	.d_write =	bpfwrite,
198 	.d_ioctl =	bpfioctl,
199 	.d_poll =	bpfpoll,
200 	.d_name =	"bpf",
201 	.d_kqfilter =	bpfkqfilter,
202 };
203 
204 static struct filterops bpfread_filtops = {
205 	.f_isfd = 1,
206 	.f_detach = filt_bpfdetach,
207 	.f_event = filt_bpfread,
208 };
209 
210 /*
211  * LOCKING MODEL USED BY BPF:
212  * Locks:
213  * 1) global lock (BPF_LOCK). Mutex, used to protect interface addition/removal,
214  * some global counters and every bpf_if reference.
215  * 2) Interface lock. Rwlock, used to protect list of BPF descriptors and their filters.
216  * 3) Descriptor lock. Rwlock, used to protect BPF buffers and various structure fields
217  *   used by bpf_mtap code.
218  *
219  * Lock order:
220  *
221  * Global lock, interface lock, descriptor lock
222  *
223  * We have to acquire interface lock before descriptor main lock due to BPF_MTAP[2]
224  * working model. In many places (like bpf_detachd) we start with BPF descriptor
225  * (and we need to at least rlock it to get reliable interface pointer). This
226  * gives us potential LOR. As a result, we use global lock to protect from bpf_if
227  * change in every such place.
228  *
229  * Changing d->bd_bif is protected by 1) global lock, 2) interface lock and
230  * 3) descriptor main wlock.
231  * Reading bd_bif can be protected by any of these locks, typically global lock.
232  *
233  * Changing read/write BPF filter is protected by the same three locks,
234  * the same applies for reading.
235  *
236  * Sleeping in global lock is not allowed due to bpfdetach() using it.
237  */
238 
239 /*
240  * Wrapper functions for various buffering methods.  If the set of buffer
241  * modes expands, we will probably want to introduce a switch data structure
242  * similar to protosw, et.
243  */
244 static void
245 bpf_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
246     u_int len)
247 {
248 
249 	BPFD_WLOCK_ASSERT(d);
250 
251 	switch (d->bd_bufmode) {
252 	case BPF_BUFMODE_BUFFER:
253 		return (bpf_buffer_append_bytes(d, buf, offset, src, len));
254 
255 	case BPF_BUFMODE_ZBUF:
256 		d->bd_zcopy++;
257 		return (bpf_zerocopy_append_bytes(d, buf, offset, src, len));
258 
259 	default:
260 		panic("bpf_buf_append_bytes");
261 	}
262 }
263 
264 static void
265 bpf_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
266     u_int len)
267 {
268 
269 	BPFD_WLOCK_ASSERT(d);
270 
271 	switch (d->bd_bufmode) {
272 	case BPF_BUFMODE_BUFFER:
273 		return (bpf_buffer_append_mbuf(d, buf, offset, src, len));
274 
275 	case BPF_BUFMODE_ZBUF:
276 		d->bd_zcopy++;
277 		return (bpf_zerocopy_append_mbuf(d, buf, offset, src, len));
278 
279 	default:
280 		panic("bpf_buf_append_mbuf");
281 	}
282 }
283 
284 /*
285  * This function gets called when the free buffer is re-assigned.
286  */
287 static void
288 bpf_buf_reclaimed(struct bpf_d *d)
289 {
290 
291 	BPFD_WLOCK_ASSERT(d);
292 
293 	switch (d->bd_bufmode) {
294 	case BPF_BUFMODE_BUFFER:
295 		return;
296 
297 	case BPF_BUFMODE_ZBUF:
298 		bpf_zerocopy_buf_reclaimed(d);
299 		return;
300 
301 	default:
302 		panic("bpf_buf_reclaimed");
303 	}
304 }
305 
306 /*
307  * If the buffer mechanism has a way to decide that a held buffer can be made
308  * free, then it is exposed via the bpf_canfreebuf() interface.  (1) is
309  * returned if the buffer can be discarded, (0) is returned if it cannot.
310  */
311 static int
312 bpf_canfreebuf(struct bpf_d *d)
313 {
314 
315 	BPFD_LOCK_ASSERT(d);
316 
317 	switch (d->bd_bufmode) {
318 	case BPF_BUFMODE_ZBUF:
319 		return (bpf_zerocopy_canfreebuf(d));
320 	}
321 	return (0);
322 }
323 
324 /*
325  * Allow the buffer model to indicate that the current store buffer is
326  * immutable, regardless of the appearance of space.  Return (1) if the
327  * buffer is writable, and (0) if not.
328  */
329 static int
330 bpf_canwritebuf(struct bpf_d *d)
331 {
332 	BPFD_LOCK_ASSERT(d);
333 
334 	switch (d->bd_bufmode) {
335 	case BPF_BUFMODE_ZBUF:
336 		return (bpf_zerocopy_canwritebuf(d));
337 	}
338 	return (1);
339 }
340 
341 /*
342  * Notify buffer model that an attempt to write to the store buffer has
343  * resulted in a dropped packet, in which case the buffer may be considered
344  * full.
345  */
346 static void
347 bpf_buffull(struct bpf_d *d)
348 {
349 
350 	BPFD_WLOCK_ASSERT(d);
351 
352 	switch (d->bd_bufmode) {
353 	case BPF_BUFMODE_ZBUF:
354 		bpf_zerocopy_buffull(d);
355 		break;
356 	}
357 }
358 
359 /*
360  * Notify the buffer model that a buffer has moved into the hold position.
361  */
362 void
363 bpf_bufheld(struct bpf_d *d)
364 {
365 
366 	BPFD_WLOCK_ASSERT(d);
367 
368 	switch (d->bd_bufmode) {
369 	case BPF_BUFMODE_ZBUF:
370 		bpf_zerocopy_bufheld(d);
371 		break;
372 	}
373 }
374 
375 static void
376 bpf_free(struct bpf_d *d)
377 {
378 
379 	switch (d->bd_bufmode) {
380 	case BPF_BUFMODE_BUFFER:
381 		return (bpf_buffer_free(d));
382 
383 	case BPF_BUFMODE_ZBUF:
384 		return (bpf_zerocopy_free(d));
385 
386 	default:
387 		panic("bpf_buf_free");
388 	}
389 }
390 
391 static int
392 bpf_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio)
393 {
394 
395 	if (d->bd_bufmode != BPF_BUFMODE_BUFFER)
396 		return (EOPNOTSUPP);
397 	return (bpf_buffer_uiomove(d, buf, len, uio));
398 }
399 
400 static int
401 bpf_ioctl_sblen(struct bpf_d *d, u_int *i)
402 {
403 
404 	if (d->bd_bufmode != BPF_BUFMODE_BUFFER)
405 		return (EOPNOTSUPP);
406 	return (bpf_buffer_ioctl_sblen(d, i));
407 }
408 
409 static int
410 bpf_ioctl_getzmax(struct thread *td, struct bpf_d *d, size_t *i)
411 {
412 
413 	if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
414 		return (EOPNOTSUPP);
415 	return (bpf_zerocopy_ioctl_getzmax(td, d, i));
416 }
417 
418 static int
419 bpf_ioctl_rotzbuf(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz)
420 {
421 
422 	if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
423 		return (EOPNOTSUPP);
424 	return (bpf_zerocopy_ioctl_rotzbuf(td, d, bz));
425 }
426 
427 static int
428 bpf_ioctl_setzbuf(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz)
429 {
430 
431 	if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
432 		return (EOPNOTSUPP);
433 	return (bpf_zerocopy_ioctl_setzbuf(td, d, bz));
434 }
435 
436 /*
437  * General BPF functions.
438  */
439 static int
440 bpf_movein(struct uio *uio, int linktype, struct ifnet *ifp, struct mbuf **mp,
441     struct sockaddr *sockp, int *hdrlen, struct bpf_insn *wfilter)
442 {
443 	const struct ieee80211_bpf_params *p;
444 	struct ether_header *eh;
445 	struct mbuf *m;
446 	int error;
447 	int len;
448 	int hlen;
449 	int slen;
450 
451 	/*
452 	 * Build a sockaddr based on the data link layer type.
453 	 * We do this at this level because the ethernet header
454 	 * is copied directly into the data field of the sockaddr.
455 	 * In the case of SLIP, there is no header and the packet
456 	 * is forwarded as is.
457 	 * Also, we are careful to leave room at the front of the mbuf
458 	 * for the link level header.
459 	 */
460 	switch (linktype) {
461 
462 	case DLT_SLIP:
463 		sockp->sa_family = AF_INET;
464 		hlen = 0;
465 		break;
466 
467 	case DLT_EN10MB:
468 		sockp->sa_family = AF_UNSPEC;
469 		/* XXX Would MAXLINKHDR be better? */
470 		hlen = ETHER_HDR_LEN;
471 		break;
472 
473 	case DLT_FDDI:
474 		sockp->sa_family = AF_IMPLINK;
475 		hlen = 0;
476 		break;
477 
478 	case DLT_RAW:
479 		sockp->sa_family = AF_UNSPEC;
480 		hlen = 0;
481 		break;
482 
483 	case DLT_NULL:
484 		/*
485 		 * null interface types require a 4 byte pseudo header which
486 		 * corresponds to the address family of the packet.
487 		 */
488 		sockp->sa_family = AF_UNSPEC;
489 		hlen = 4;
490 		break;
491 
492 	case DLT_ATM_RFC1483:
493 		/*
494 		 * en atm driver requires 4-byte atm pseudo header.
495 		 * though it isn't standard, vpi:vci needs to be
496 		 * specified anyway.
497 		 */
498 		sockp->sa_family = AF_UNSPEC;
499 		hlen = 12;	/* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
500 		break;
501 
502 	case DLT_PPP:
503 		sockp->sa_family = AF_UNSPEC;
504 		hlen = 4;	/* This should match PPP_HDRLEN */
505 		break;
506 
507 	case DLT_IEEE802_11:		/* IEEE 802.11 wireless */
508 		sockp->sa_family = AF_IEEE80211;
509 		hlen = 0;
510 		break;
511 
512 	case DLT_IEEE802_11_RADIO:	/* IEEE 802.11 wireless w/ phy params */
513 		sockp->sa_family = AF_IEEE80211;
514 		sockp->sa_len = 12;	/* XXX != 0 */
515 		hlen = sizeof(struct ieee80211_bpf_params);
516 		break;
517 
518 	default:
519 		return (EIO);
520 	}
521 
522 	len = uio->uio_resid;
523 
524 	if (len - hlen > ifp->if_mtu)
525 		return (EMSGSIZE);
526 
527 	if ((unsigned)len > MJUM16BYTES)
528 		return (EIO);
529 
530 	if (len <= MHLEN)
531 		MGETHDR(m, M_WAIT, MT_DATA);
532 	else if (len <= MCLBYTES)
533 		m = m_getcl(M_WAIT, MT_DATA, M_PKTHDR);
534 	else
535 		m = m_getjcl(M_WAIT, MT_DATA, M_PKTHDR,
536 #if (MJUMPAGESIZE > MCLBYTES)
537 		    len <= MJUMPAGESIZE ? MJUMPAGESIZE :
538 #endif
539 		    (len <= MJUM9BYTES ? MJUM9BYTES : MJUM16BYTES));
540 	m->m_pkthdr.len = m->m_len = len;
541 	m->m_pkthdr.rcvif = NULL;
542 	*mp = m;
543 
544 	if (m->m_len < hlen) {
545 		error = EPERM;
546 		goto bad;
547 	}
548 
549 	error = uiomove(mtod(m, u_char *), len, uio);
550 	if (error)
551 		goto bad;
552 
553 	slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
554 	if (slen == 0) {
555 		error = EPERM;
556 		goto bad;
557 	}
558 
559 	/* Check for multicast destination */
560 	switch (linktype) {
561 	case DLT_EN10MB:
562 		eh = mtod(m, struct ether_header *);
563 		if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
564 			if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost,
565 			    ETHER_ADDR_LEN) == 0)
566 				m->m_flags |= M_BCAST;
567 			else
568 				m->m_flags |= M_MCAST;
569 		}
570 		break;
571 	}
572 
573 	/*
574 	 * Make room for link header, and copy it to sockaddr
575 	 */
576 	if (hlen != 0) {
577 		if (sockp->sa_family == AF_IEEE80211) {
578 			/*
579 			 * Collect true length from the parameter header
580 			 * NB: sockp is known to be zero'd so if we do a
581 			 *     short copy unspecified parameters will be
582 			 *     zero.
583 			 * NB: packet may not be aligned after stripping
584 			 *     bpf params
585 			 * XXX check ibp_vers
586 			 */
587 			p = mtod(m, const struct ieee80211_bpf_params *);
588 			hlen = p->ibp_len;
589 			if (hlen > sizeof(sockp->sa_data)) {
590 				error = EINVAL;
591 				goto bad;
592 			}
593 		}
594 		bcopy(m->m_data, sockp->sa_data, hlen);
595 	}
596 	*hdrlen = hlen;
597 
598 	return (0);
599 bad:
600 	m_freem(m);
601 	return (error);
602 }
603 
604 /*
605  * Attach file to the bpf interface, i.e. make d listen on bp.
606  */
607 static void
608 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
609 {
610 	int op_w;
611 
612 	BPF_LOCK_ASSERT();
613 
614 	/*
615 	 * Save sysctl value to protect from sysctl change
616 	 * between reads
617 	 */
618 	op_w = V_bpf_optimize_writers;
619 
620 	if (d->bd_bif != NULL)
621 		bpf_detachd_locked(d);
622 	/*
623 	 * Point d at bp, and add d to the interface's list.
624 	 * Since there are many applicaiotns using BPF for
625 	 * sending raw packets only (dhcpd, cdpd are good examples)
626 	 * we can delay adding d to the list of active listeners until
627 	 * some filter is configured.
628 	 */
629 
630 	BPFIF_WLOCK(bp);
631 	BPFD_WLOCK(d);
632 
633 	d->bd_bif = bp;
634 
635 	if (op_w != 0) {
636 		/* Add to writers-only list */
637 		LIST_INSERT_HEAD(&bp->bif_wlist, d, bd_next);
638 		/*
639 		 * We decrement bd_writer on every filter set operation.
640 		 * First BIOCSETF is done by pcap_open_live() to set up
641 		 * snap length. After that appliation usually sets its own filter
642 		 */
643 		d->bd_writer = 2;
644 	} else
645 		LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
646 
647 	BPFD_WUNLOCK(d);
648 	BPFIF_WUNLOCK(bp);
649 
650 	bpf_bpfd_cnt++;
651 
652 	CTR3(KTR_NET, "%s: bpf_attach called by pid %d, adding to %s list",
653 	    __func__, d->bd_pid, d->bd_writer ? "writer" : "active");
654 
655 	if (op_w == 0)
656 		EVENTHANDLER_INVOKE(bpf_track, bp->bif_ifp, bp->bif_dlt, 1);
657 }
658 
659 /*
660  * Add d to the list of active bp filters.
661  * Reuqires bpf_attachd() to be called before
662  */
663 static void
664 bpf_upgraded(struct bpf_d *d)
665 {
666 	struct bpf_if *bp;
667 
668 	BPF_LOCK_ASSERT();
669 
670 	bp = d->bd_bif;
671 
672 	/*
673 	 * Filter can be set several times without specifying interface.
674 	 * Mark d as reader and exit.
675 	 */
676 	if (bp == NULL) {
677 		BPFD_WLOCK(d);
678 		d->bd_writer = 0;
679 		BPFD_WUNLOCK(d);
680 		return;
681 	}
682 
683 	BPFIF_WLOCK(bp);
684 	BPFD_WLOCK(d);
685 
686 	/* Remove from writers-only list */
687 	LIST_REMOVE(d, bd_next);
688 	LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
689 	/* Mark d as reader */
690 	d->bd_writer = 0;
691 
692 	BPFD_WUNLOCK(d);
693 	BPFIF_WUNLOCK(bp);
694 
695 	CTR2(KTR_NET, "%s: upgrade required by pid %d", __func__, d->bd_pid);
696 
697 	EVENTHANDLER_INVOKE(bpf_track, bp->bif_ifp, bp->bif_dlt, 1);
698 }
699 
700 /*
701  * Detach a file from its interface.
702  */
703 static void
704 bpf_detachd(struct bpf_d *d)
705 {
706 	BPF_LOCK();
707 	bpf_detachd_locked(d);
708 	BPF_UNLOCK();
709 }
710 
711 static void
712 bpf_detachd_locked(struct bpf_d *d)
713 {
714 	int error;
715 	struct bpf_if *bp;
716 	struct ifnet *ifp;
717 
718 	CTR2(KTR_NET, "%s: detach required by pid %d", __func__, d->bd_pid);
719 
720 	BPF_LOCK_ASSERT();
721 
722 	/* Check if descriptor is attached */
723 	if ((bp = d->bd_bif) == NULL)
724 		return;
725 
726 	BPFIF_WLOCK(bp);
727 	BPFD_WLOCK(d);
728 
729 	/* Save bd_writer value */
730 	error = d->bd_writer;
731 
732 	/*
733 	 * Remove d from the interface's descriptor list.
734 	 */
735 	LIST_REMOVE(d, bd_next);
736 
737 	ifp = bp->bif_ifp;
738 	d->bd_bif = NULL;
739 	BPFD_WUNLOCK(d);
740 	BPFIF_WUNLOCK(bp);
741 
742 	bpf_bpfd_cnt--;
743 
744 	/* Call event handler iff d is attached */
745 	if (error == 0)
746 		EVENTHANDLER_INVOKE(bpf_track, ifp, bp->bif_dlt, 0);
747 
748 	/*
749 	 * Check if this descriptor had requested promiscuous mode.
750 	 * If so, turn it off.
751 	 */
752 	if (d->bd_promisc) {
753 		d->bd_promisc = 0;
754 		CURVNET_SET(ifp->if_vnet);
755 		error = ifpromisc(ifp, 0);
756 		CURVNET_RESTORE();
757 		if (error != 0 && error != ENXIO) {
758 			/*
759 			 * ENXIO can happen if a pccard is unplugged
760 			 * Something is really wrong if we were able to put
761 			 * the driver into promiscuous mode, but can't
762 			 * take it out.
763 			 */
764 			if_printf(bp->bif_ifp,
765 				"bpf_detach: ifpromisc failed (%d)\n", error);
766 		}
767 	}
768 }
769 
770 /*
771  * Close the descriptor by detaching it from its interface,
772  * deallocating its buffers, and marking it free.
773  */
774 static void
775 bpf_dtor(void *data)
776 {
777 	struct bpf_d *d = data;
778 
779 	BPFD_WLOCK(d);
780 	if (d->bd_state == BPF_WAITING)
781 		callout_stop(&d->bd_callout);
782 	d->bd_state = BPF_IDLE;
783 	BPFD_WUNLOCK(d);
784 	funsetown(&d->bd_sigio);
785 	bpf_detachd(d);
786 #ifdef MAC
787 	mac_bpfdesc_destroy(d);
788 #endif /* MAC */
789 	seldrain(&d->bd_sel);
790 	knlist_destroy(&d->bd_sel.si_note);
791 	callout_drain(&d->bd_callout);
792 	bpf_freed(d);
793 	free(d, M_BPF);
794 }
795 
796 /*
797  * Open ethernet device.  Returns ENXIO for illegal minor device number,
798  * EBUSY if file is open by another process.
799  */
800 /* ARGSUSED */
801 static	int
802 bpfopen(struct cdev *dev, int flags, int fmt, struct thread *td)
803 {
804 	struct bpf_d *d;
805 	int error;
806 
807 	d = malloc(sizeof(*d), M_BPF, M_WAITOK | M_ZERO);
808 	error = devfs_set_cdevpriv(d, bpf_dtor);
809 	if (error != 0) {
810 		free(d, M_BPF);
811 		return (error);
812 	}
813 
814 	/*
815 	 * For historical reasons, perform a one-time initialization call to
816 	 * the buffer routines, even though we're not yet committed to a
817 	 * particular buffer method.
818 	 */
819 	bpf_buffer_init(d);
820 	d->bd_bufmode = BPF_BUFMODE_BUFFER;
821 	d->bd_sig = SIGIO;
822 	d->bd_direction = BPF_D_INOUT;
823 	BPF_PID_REFRESH(d, td);
824 #ifdef MAC
825 	mac_bpfdesc_init(d);
826 	mac_bpfdesc_create(td->td_ucred, d);
827 #endif
828 	rw_init(&d->bd_lock, "bpf cdev lock");
829 	callout_init_rw(&d->bd_callout, &d->bd_lock, 0);
830 	knlist_init_rw_reader(&d->bd_sel.si_note, &d->bd_lock);
831 
832 	return (0);
833 }
834 
835 /*
836  *  bpfread - read next chunk of packets from buffers
837  */
838 static	int
839 bpfread(struct cdev *dev, struct uio *uio, int ioflag)
840 {
841 	struct bpf_d *d;
842 	int error;
843 	int non_block;
844 	int timed_out;
845 
846 	error = devfs_get_cdevpriv((void **)&d);
847 	if (error != 0)
848 		return (error);
849 
850 	/*
851 	 * Restrict application to use a buffer the same size as
852 	 * as kernel buffers.
853 	 */
854 	if (uio->uio_resid != d->bd_bufsize)
855 		return (EINVAL);
856 
857 	non_block = ((ioflag & O_NONBLOCK) != 0);
858 
859 	BPFD_WLOCK(d);
860 	BPF_PID_REFRESH_CUR(d);
861 	if (d->bd_bufmode != BPF_BUFMODE_BUFFER) {
862 		BPFD_WUNLOCK(d);
863 		return (EOPNOTSUPP);
864 	}
865 	if (d->bd_state == BPF_WAITING)
866 		callout_stop(&d->bd_callout);
867 	timed_out = (d->bd_state == BPF_TIMED_OUT);
868 	d->bd_state = BPF_IDLE;
869 	/*
870 	 * If the hold buffer is empty, then do a timed sleep, which
871 	 * ends when the timeout expires or when enough packets
872 	 * have arrived to fill the store buffer.
873 	 */
874 	while (d->bd_hbuf == NULL) {
875 		if (d->bd_slen != 0) {
876 			/*
877 			 * A packet(s) either arrived since the previous
878 			 * read or arrived while we were asleep.
879 			 */
880 			if (d->bd_immediate || non_block || timed_out) {
881 				/*
882 				 * Rotate the buffers and return what's here
883 				 * if we are in immediate mode, non-blocking
884 				 * flag is set, or this descriptor timed out.
885 				 */
886 				ROTATE_BUFFERS(d);
887 				break;
888 			}
889 		}
890 
891 		/*
892 		 * No data is available, check to see if the bpf device
893 		 * is still pointed at a real interface.  If not, return
894 		 * ENXIO so that the userland process knows to rebind
895 		 * it before using it again.
896 		 */
897 		if (d->bd_bif == NULL) {
898 			BPFD_WUNLOCK(d);
899 			return (ENXIO);
900 		}
901 
902 		if (non_block) {
903 			BPFD_WUNLOCK(d);
904 			return (EWOULDBLOCK);
905 		}
906 		error = rw_sleep(d, &d->bd_lock, PRINET|PCATCH,
907 		     "bpf", d->bd_rtout);
908 		if (error == EINTR || error == ERESTART) {
909 			BPFD_WUNLOCK(d);
910 			return (error);
911 		}
912 		if (error == EWOULDBLOCK) {
913 			/*
914 			 * On a timeout, return what's in the buffer,
915 			 * which may be nothing.  If there is something
916 			 * in the store buffer, we can rotate the buffers.
917 			 */
918 			if (d->bd_hbuf)
919 				/*
920 				 * We filled up the buffer in between
921 				 * getting the timeout and arriving
922 				 * here, so we don't need to rotate.
923 				 */
924 				break;
925 
926 			if (d->bd_slen == 0) {
927 				BPFD_WUNLOCK(d);
928 				return (0);
929 			}
930 			ROTATE_BUFFERS(d);
931 			break;
932 		}
933 	}
934 	/*
935 	 * At this point, we know we have something in the hold slot.
936 	 */
937 	BPFD_WUNLOCK(d);
938 
939 	/*
940 	 * Move data from hold buffer into user space.
941 	 * We know the entire buffer is transferred since
942 	 * we checked above that the read buffer is bpf_bufsize bytes.
943 	 *
944 	 * XXXRW: More synchronization needed here: what if a second thread
945 	 * issues a read on the same fd at the same time?  Don't want this
946 	 * getting invalidated.
947 	 */
948 	error = bpf_uiomove(d, d->bd_hbuf, d->bd_hlen, uio);
949 
950 	BPFD_WLOCK(d);
951 	d->bd_fbuf = d->bd_hbuf;
952 	d->bd_hbuf = NULL;
953 	d->bd_hlen = 0;
954 	bpf_buf_reclaimed(d);
955 	BPFD_WUNLOCK(d);
956 
957 	return (error);
958 }
959 
960 /*
961  * If there are processes sleeping on this descriptor, wake them up.
962  */
963 static __inline void
964 bpf_wakeup(struct bpf_d *d)
965 {
966 
967 	BPFD_WLOCK_ASSERT(d);
968 	if (d->bd_state == BPF_WAITING) {
969 		callout_stop(&d->bd_callout);
970 		d->bd_state = BPF_IDLE;
971 	}
972 	wakeup(d);
973 	if (d->bd_async && d->bd_sig && d->bd_sigio)
974 		pgsigio(&d->bd_sigio, d->bd_sig, 0);
975 
976 	selwakeuppri(&d->bd_sel, PRINET);
977 	KNOTE_LOCKED(&d->bd_sel.si_note, 0);
978 }
979 
980 static void
981 bpf_timed_out(void *arg)
982 {
983 	struct bpf_d *d = (struct bpf_d *)arg;
984 
985 	BPFD_WLOCK_ASSERT(d);
986 
987 	if (callout_pending(&d->bd_callout) || !callout_active(&d->bd_callout))
988 		return;
989 	if (d->bd_state == BPF_WAITING) {
990 		d->bd_state = BPF_TIMED_OUT;
991 		if (d->bd_slen != 0)
992 			bpf_wakeup(d);
993 	}
994 }
995 
996 static int
997 bpf_ready(struct bpf_d *d)
998 {
999 
1000 	BPFD_WLOCK_ASSERT(d);
1001 
1002 	if (!bpf_canfreebuf(d) && d->bd_hlen != 0)
1003 		return (1);
1004 	if ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1005 	    d->bd_slen != 0)
1006 		return (1);
1007 	return (0);
1008 }
1009 
1010 static int
1011 bpfwrite(struct cdev *dev, struct uio *uio, int ioflag)
1012 {
1013 	struct bpf_d *d;
1014 	struct ifnet *ifp;
1015 	struct mbuf *m, *mc;
1016 	struct sockaddr dst;
1017 	int error, hlen;
1018 
1019 	error = devfs_get_cdevpriv((void **)&d);
1020 	if (error != 0)
1021 		return (error);
1022 
1023 	BPF_PID_REFRESH_CUR(d);
1024 	d->bd_wcount++;
1025 	/* XXX: locking required */
1026 	if (d->bd_bif == NULL) {
1027 		d->bd_wdcount++;
1028 		return (ENXIO);
1029 	}
1030 
1031 	ifp = d->bd_bif->bif_ifp;
1032 
1033 	if ((ifp->if_flags & IFF_UP) == 0) {
1034 		d->bd_wdcount++;
1035 		return (ENETDOWN);
1036 	}
1037 
1038 	if (uio->uio_resid == 0) {
1039 		d->bd_wdcount++;
1040 		return (0);
1041 	}
1042 
1043 	bzero(&dst, sizeof(dst));
1044 	m = NULL;
1045 	hlen = 0;
1046 	/* XXX: bpf_movein() can sleep */
1047 	error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp,
1048 	    &m, &dst, &hlen, d->bd_wfilter);
1049 	if (error) {
1050 		d->bd_wdcount++;
1051 		return (error);
1052 	}
1053 	d->bd_wfcount++;
1054 	if (d->bd_hdrcmplt)
1055 		dst.sa_family = pseudo_AF_HDRCMPLT;
1056 
1057 	if (d->bd_feedback) {
1058 		mc = m_dup(m, M_DONTWAIT);
1059 		if (mc != NULL)
1060 			mc->m_pkthdr.rcvif = ifp;
1061 		/* Set M_PROMISC for outgoing packets to be discarded. */
1062 		if (d->bd_direction == BPF_D_INOUT)
1063 			m->m_flags |= M_PROMISC;
1064 	} else
1065 		mc = NULL;
1066 
1067 	m->m_pkthdr.len -= hlen;
1068 	m->m_len -= hlen;
1069 	m->m_data += hlen;	/* XXX */
1070 
1071 	CURVNET_SET(ifp->if_vnet);
1072 #ifdef MAC
1073 	BPFD_WLOCK(d);
1074 	mac_bpfdesc_create_mbuf(d, m);
1075 	if (mc != NULL)
1076 		mac_bpfdesc_create_mbuf(d, mc);
1077 	BPFD_WUNLOCK(d);
1078 #endif
1079 
1080 	error = (*ifp->if_output)(ifp, m, &dst, NULL);
1081 	if (error)
1082 		d->bd_wdcount++;
1083 
1084 	if (mc != NULL) {
1085 		if (error == 0)
1086 			(*ifp->if_input)(ifp, mc);
1087 		else
1088 			m_freem(mc);
1089 	}
1090 	CURVNET_RESTORE();
1091 
1092 	return (error);
1093 }
1094 
1095 /*
1096  * Reset a descriptor by flushing its packet buffer and clearing the receive
1097  * and drop counts.  This is doable for kernel-only buffers, but with
1098  * zero-copy buffers, we can't write to (or rotate) buffers that are
1099  * currently owned by userspace.  It would be nice if we could encapsulate
1100  * this logic in the buffer code rather than here.
1101  */
1102 static void
1103 reset_d(struct bpf_d *d)
1104 {
1105 
1106 	BPFD_WLOCK_ASSERT(d);
1107 
1108 	if ((d->bd_hbuf != NULL) &&
1109 	    (d->bd_bufmode != BPF_BUFMODE_ZBUF || bpf_canfreebuf(d))) {
1110 		/* Free the hold buffer. */
1111 		d->bd_fbuf = d->bd_hbuf;
1112 		d->bd_hbuf = NULL;
1113 		d->bd_hlen = 0;
1114 		bpf_buf_reclaimed(d);
1115 	}
1116 	if (bpf_canwritebuf(d))
1117 		d->bd_slen = 0;
1118 	d->bd_rcount = 0;
1119 	d->bd_dcount = 0;
1120 	d->bd_fcount = 0;
1121 	d->bd_wcount = 0;
1122 	d->bd_wfcount = 0;
1123 	d->bd_wdcount = 0;
1124 	d->bd_zcopy = 0;
1125 }
1126 
1127 /*
1128  *  FIONREAD		Check for read packet available.
1129  *  SIOCGIFADDR		Get interface address - convenient hook to driver.
1130  *  BIOCGBLEN		Get buffer len [for read()].
1131  *  BIOCSETF		Set read filter.
1132  *  BIOCSETFNR		Set read filter without resetting descriptor.
1133  *  BIOCSETWF		Set write filter.
1134  *  BIOCFLUSH		Flush read packet buffer.
1135  *  BIOCPROMISC		Put interface into promiscuous mode.
1136  *  BIOCGDLT		Get link layer type.
1137  *  BIOCGETIF		Get interface name.
1138  *  BIOCSETIF		Set interface.
1139  *  BIOCSRTIMEOUT	Set read timeout.
1140  *  BIOCGRTIMEOUT	Get read timeout.
1141  *  BIOCGSTATS		Get packet stats.
1142  *  BIOCIMMEDIATE	Set immediate mode.
1143  *  BIOCVERSION		Get filter language version.
1144  *  BIOCGHDRCMPLT	Get "header already complete" flag
1145  *  BIOCSHDRCMPLT	Set "header already complete" flag
1146  *  BIOCGDIRECTION	Get packet direction flag
1147  *  BIOCSDIRECTION	Set packet direction flag
1148  *  BIOCGTSTAMP		Get time stamp format and resolution.
1149  *  BIOCSTSTAMP		Set time stamp format and resolution.
1150  *  BIOCLOCK		Set "locked" flag
1151  *  BIOCFEEDBACK	Set packet feedback mode.
1152  *  BIOCSETZBUF		Set current zero-copy buffer locations.
1153  *  BIOCGETZMAX		Get maximum zero-copy buffer size.
1154  *  BIOCROTZBUF		Force rotation of zero-copy buffer
1155  *  BIOCSETBUFMODE	Set buffer mode.
1156  *  BIOCGETBUFMODE	Get current buffer mode.
1157  */
1158 /* ARGSUSED */
1159 static	int
1160 bpfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
1161     struct thread *td)
1162 {
1163 	struct bpf_d *d;
1164 	int error;
1165 
1166 	error = devfs_get_cdevpriv((void **)&d);
1167 	if (error != 0)
1168 		return (error);
1169 
1170 	/*
1171 	 * Refresh PID associated with this descriptor.
1172 	 */
1173 	BPFD_WLOCK(d);
1174 	BPF_PID_REFRESH(d, td);
1175 	if (d->bd_state == BPF_WAITING)
1176 		callout_stop(&d->bd_callout);
1177 	d->bd_state = BPF_IDLE;
1178 	BPFD_WUNLOCK(d);
1179 
1180 	if (d->bd_locked == 1) {
1181 		switch (cmd) {
1182 		case BIOCGBLEN:
1183 		case BIOCFLUSH:
1184 		case BIOCGDLT:
1185 		case BIOCGDLTLIST:
1186 #ifdef COMPAT_FREEBSD32
1187 		case BIOCGDLTLIST32:
1188 #endif
1189 		case BIOCGETIF:
1190 		case BIOCGRTIMEOUT:
1191 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1192 		case BIOCGRTIMEOUT32:
1193 #endif
1194 		case BIOCGSTATS:
1195 		case BIOCVERSION:
1196 		case BIOCGRSIG:
1197 		case BIOCGHDRCMPLT:
1198 		case BIOCSTSTAMP:
1199 		case BIOCFEEDBACK:
1200 		case FIONREAD:
1201 		case BIOCLOCK:
1202 		case BIOCSRTIMEOUT:
1203 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1204 		case BIOCSRTIMEOUT32:
1205 #endif
1206 		case BIOCIMMEDIATE:
1207 		case TIOCGPGRP:
1208 		case BIOCROTZBUF:
1209 			break;
1210 		default:
1211 			return (EPERM);
1212 		}
1213 	}
1214 #ifdef COMPAT_FREEBSD32
1215 	/*
1216 	 * If we see a 32-bit compat ioctl, mark the stream as 32-bit so
1217 	 * that it will get 32-bit packet headers.
1218 	 */
1219 	switch (cmd) {
1220 	case BIOCSETF32:
1221 	case BIOCSETFNR32:
1222 	case BIOCSETWF32:
1223 	case BIOCGDLTLIST32:
1224 	case BIOCGRTIMEOUT32:
1225 	case BIOCSRTIMEOUT32:
1226 		d->bd_compat32 = 1;
1227 	}
1228 #endif
1229 
1230 	CURVNET_SET(TD_TO_VNET(td));
1231 	switch (cmd) {
1232 
1233 	default:
1234 		error = EINVAL;
1235 		break;
1236 
1237 	/*
1238 	 * Check for read packet available.
1239 	 */
1240 	case FIONREAD:
1241 		{
1242 			int n;
1243 
1244 			BPFD_WLOCK(d);
1245 			n = d->bd_slen;
1246 			if (d->bd_hbuf)
1247 				n += d->bd_hlen;
1248 			BPFD_WUNLOCK(d);
1249 
1250 			*(int *)addr = n;
1251 			break;
1252 		}
1253 
1254 	case SIOCGIFADDR:
1255 		{
1256 			struct ifnet *ifp;
1257 
1258 			if (d->bd_bif == NULL)
1259 				error = EINVAL;
1260 			else {
1261 				ifp = d->bd_bif->bif_ifp;
1262 				error = (*ifp->if_ioctl)(ifp, cmd, addr);
1263 			}
1264 			break;
1265 		}
1266 
1267 	/*
1268 	 * Get buffer len [for read()].
1269 	 */
1270 	case BIOCGBLEN:
1271 		*(u_int *)addr = d->bd_bufsize;
1272 		break;
1273 
1274 	/*
1275 	 * Set buffer length.
1276 	 */
1277 	case BIOCSBLEN:
1278 		error = bpf_ioctl_sblen(d, (u_int *)addr);
1279 		break;
1280 
1281 	/*
1282 	 * Set link layer read filter.
1283 	 */
1284 	case BIOCSETF:
1285 	case BIOCSETFNR:
1286 	case BIOCSETWF:
1287 #ifdef COMPAT_FREEBSD32
1288 	case BIOCSETF32:
1289 	case BIOCSETFNR32:
1290 	case BIOCSETWF32:
1291 #endif
1292 		error = bpf_setf(d, (struct bpf_program *)addr, cmd);
1293 		break;
1294 
1295 	/*
1296 	 * Flush read packet buffer.
1297 	 */
1298 	case BIOCFLUSH:
1299 		BPFD_WLOCK(d);
1300 		reset_d(d);
1301 		BPFD_WUNLOCK(d);
1302 		break;
1303 
1304 	/*
1305 	 * Put interface into promiscuous mode.
1306 	 */
1307 	case BIOCPROMISC:
1308 		if (d->bd_bif == NULL) {
1309 			/*
1310 			 * No interface attached yet.
1311 			 */
1312 			error = EINVAL;
1313 			break;
1314 		}
1315 		if (d->bd_promisc == 0) {
1316 			error = ifpromisc(d->bd_bif->bif_ifp, 1);
1317 			if (error == 0)
1318 				d->bd_promisc = 1;
1319 		}
1320 		break;
1321 
1322 	/*
1323 	 * Get current data link type.
1324 	 */
1325 	case BIOCGDLT:
1326 		if (d->bd_bif == NULL)
1327 			error = EINVAL;
1328 		else
1329 			*(u_int *)addr = d->bd_bif->bif_dlt;
1330 		break;
1331 
1332 	/*
1333 	 * Get a list of supported data link types.
1334 	 */
1335 #ifdef COMPAT_FREEBSD32
1336 	case BIOCGDLTLIST32:
1337 		{
1338 			struct bpf_dltlist32 *list32;
1339 			struct bpf_dltlist dltlist;
1340 
1341 			list32 = (struct bpf_dltlist32 *)addr;
1342 			dltlist.bfl_len = list32->bfl_len;
1343 			dltlist.bfl_list = PTRIN(list32->bfl_list);
1344 			if (d->bd_bif == NULL)
1345 				error = EINVAL;
1346 			else {
1347 				error = bpf_getdltlist(d, &dltlist);
1348 				if (error == 0)
1349 					list32->bfl_len = dltlist.bfl_len;
1350 			}
1351 			break;
1352 		}
1353 #endif
1354 
1355 	case BIOCGDLTLIST:
1356 		if (d->bd_bif == NULL)
1357 			error = EINVAL;
1358 		else
1359 			error = bpf_getdltlist(d, (struct bpf_dltlist *)addr);
1360 		break;
1361 
1362 	/*
1363 	 * Set data link type.
1364 	 */
1365 	case BIOCSDLT:
1366 		BPF_LOCK();
1367 		if (d->bd_bif == NULL)
1368 			error = EINVAL;
1369 		else
1370 			error = bpf_setdlt(d, *(u_int *)addr);
1371 		BPF_UNLOCK();
1372 		break;
1373 
1374 	/*
1375 	 * Get interface name.
1376 	 */
1377 	case BIOCGETIF:
1378 		if (d->bd_bif == NULL)
1379 			error = EINVAL;
1380 		else {
1381 			struct ifnet *const ifp = d->bd_bif->bif_ifp;
1382 			struct ifreq *const ifr = (struct ifreq *)addr;
1383 
1384 			strlcpy(ifr->ifr_name, ifp->if_xname,
1385 			    sizeof(ifr->ifr_name));
1386 		}
1387 		break;
1388 
1389 	/*
1390 	 * Set interface.
1391 	 */
1392 	case BIOCSETIF:
1393 		BPF_LOCK();
1394 		error = bpf_setif(d, (struct ifreq *)addr);
1395 		BPF_UNLOCK();
1396 		break;
1397 
1398 	/*
1399 	 * Set read timeout.
1400 	 */
1401 	case BIOCSRTIMEOUT:
1402 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1403 	case BIOCSRTIMEOUT32:
1404 #endif
1405 		{
1406 			struct timeval *tv = (struct timeval *)addr;
1407 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1408 			struct timeval32 *tv32;
1409 			struct timeval tv64;
1410 
1411 			if (cmd == BIOCSRTIMEOUT32) {
1412 				tv32 = (struct timeval32 *)addr;
1413 				tv = &tv64;
1414 				tv->tv_sec = tv32->tv_sec;
1415 				tv->tv_usec = tv32->tv_usec;
1416 			} else
1417 #endif
1418 				tv = (struct timeval *)addr;
1419 
1420 			/*
1421 			 * Subtract 1 tick from tvtohz() since this isn't
1422 			 * a one-shot timer.
1423 			 */
1424 			if ((error = itimerfix(tv)) == 0)
1425 				d->bd_rtout = tvtohz(tv) - 1;
1426 			break;
1427 		}
1428 
1429 	/*
1430 	 * Get read timeout.
1431 	 */
1432 	case BIOCGRTIMEOUT:
1433 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1434 	case BIOCGRTIMEOUT32:
1435 #endif
1436 		{
1437 			struct timeval *tv;
1438 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1439 			struct timeval32 *tv32;
1440 			struct timeval tv64;
1441 
1442 			if (cmd == BIOCGRTIMEOUT32)
1443 				tv = &tv64;
1444 			else
1445 #endif
1446 				tv = (struct timeval *)addr;
1447 
1448 			tv->tv_sec = d->bd_rtout / hz;
1449 			tv->tv_usec = (d->bd_rtout % hz) * tick;
1450 #if defined(COMPAT_FREEBSD32) && !defined(__mips__)
1451 			if (cmd == BIOCGRTIMEOUT32) {
1452 				tv32 = (struct timeval32 *)addr;
1453 				tv32->tv_sec = tv->tv_sec;
1454 				tv32->tv_usec = tv->tv_usec;
1455 			}
1456 #endif
1457 
1458 			break;
1459 		}
1460 
1461 	/*
1462 	 * Get packet stats.
1463 	 */
1464 	case BIOCGSTATS:
1465 		{
1466 			struct bpf_stat *bs = (struct bpf_stat *)addr;
1467 
1468 			/* XXXCSJP overflow */
1469 			bs->bs_recv = d->bd_rcount;
1470 			bs->bs_drop = d->bd_dcount;
1471 			break;
1472 		}
1473 
1474 	/*
1475 	 * Set immediate mode.
1476 	 */
1477 	case BIOCIMMEDIATE:
1478 		d->bd_immediate = *(u_int *)addr;
1479 		break;
1480 
1481 	case BIOCVERSION:
1482 		{
1483 			struct bpf_version *bv = (struct bpf_version *)addr;
1484 
1485 			bv->bv_major = BPF_MAJOR_VERSION;
1486 			bv->bv_minor = BPF_MINOR_VERSION;
1487 			break;
1488 		}
1489 
1490 	/*
1491 	 * Get "header already complete" flag
1492 	 */
1493 	case BIOCGHDRCMPLT:
1494 		*(u_int *)addr = d->bd_hdrcmplt;
1495 		break;
1496 
1497 	/*
1498 	 * Set "header already complete" flag
1499 	 */
1500 	case BIOCSHDRCMPLT:
1501 		d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
1502 		break;
1503 
1504 	/*
1505 	 * Get packet direction flag
1506 	 */
1507 	case BIOCGDIRECTION:
1508 		*(u_int *)addr = d->bd_direction;
1509 		break;
1510 
1511 	/*
1512 	 * Set packet direction flag
1513 	 */
1514 	case BIOCSDIRECTION:
1515 		{
1516 			u_int	direction;
1517 
1518 			direction = *(u_int *)addr;
1519 			switch (direction) {
1520 			case BPF_D_IN:
1521 			case BPF_D_INOUT:
1522 			case BPF_D_OUT:
1523 				d->bd_direction = direction;
1524 				break;
1525 			default:
1526 				error = EINVAL;
1527 			}
1528 		}
1529 		break;
1530 
1531 	/*
1532 	 * Get packet timestamp format and resolution.
1533 	 */
1534 	case BIOCGTSTAMP:
1535 		*(u_int *)addr = d->bd_tstamp;
1536 		break;
1537 
1538 	/*
1539 	 * Set packet timestamp format and resolution.
1540 	 */
1541 	case BIOCSTSTAMP:
1542 		{
1543 			u_int	func;
1544 
1545 			func = *(u_int *)addr;
1546 			if (BPF_T_VALID(func))
1547 				d->bd_tstamp = func;
1548 			else
1549 				error = EINVAL;
1550 		}
1551 		break;
1552 
1553 	case BIOCFEEDBACK:
1554 		d->bd_feedback = *(u_int *)addr;
1555 		break;
1556 
1557 	case BIOCLOCK:
1558 		d->bd_locked = 1;
1559 		break;
1560 
1561 	case FIONBIO:		/* Non-blocking I/O */
1562 		break;
1563 
1564 	case FIOASYNC:		/* Send signal on receive packets */
1565 		d->bd_async = *(int *)addr;
1566 		break;
1567 
1568 	case FIOSETOWN:
1569 		error = fsetown(*(int *)addr, &d->bd_sigio);
1570 		break;
1571 
1572 	case FIOGETOWN:
1573 		*(int *)addr = fgetown(&d->bd_sigio);
1574 		break;
1575 
1576 	/* This is deprecated, FIOSETOWN should be used instead. */
1577 	case TIOCSPGRP:
1578 		error = fsetown(-(*(int *)addr), &d->bd_sigio);
1579 		break;
1580 
1581 	/* This is deprecated, FIOGETOWN should be used instead. */
1582 	case TIOCGPGRP:
1583 		*(int *)addr = -fgetown(&d->bd_sigio);
1584 		break;
1585 
1586 	case BIOCSRSIG:		/* Set receive signal */
1587 		{
1588 			u_int sig;
1589 
1590 			sig = *(u_int *)addr;
1591 
1592 			if (sig >= NSIG)
1593 				error = EINVAL;
1594 			else
1595 				d->bd_sig = sig;
1596 			break;
1597 		}
1598 	case BIOCGRSIG:
1599 		*(u_int *)addr = d->bd_sig;
1600 		break;
1601 
1602 	case BIOCGETBUFMODE:
1603 		*(u_int *)addr = d->bd_bufmode;
1604 		break;
1605 
1606 	case BIOCSETBUFMODE:
1607 		/*
1608 		 * Allow the buffering mode to be changed as long as we
1609 		 * haven't yet committed to a particular mode.  Our
1610 		 * definition of commitment, for now, is whether or not a
1611 		 * buffer has been allocated or an interface attached, since
1612 		 * that's the point where things get tricky.
1613 		 */
1614 		switch (*(u_int *)addr) {
1615 		case BPF_BUFMODE_BUFFER:
1616 			break;
1617 
1618 		case BPF_BUFMODE_ZBUF:
1619 			if (bpf_zerocopy_enable)
1620 				break;
1621 			/* FALLSTHROUGH */
1622 
1623 		default:
1624 			CURVNET_RESTORE();
1625 			return (EINVAL);
1626 		}
1627 
1628 		BPFD_WLOCK(d);
1629 		if (d->bd_sbuf != NULL || d->bd_hbuf != NULL ||
1630 		    d->bd_fbuf != NULL || d->bd_bif != NULL) {
1631 			BPFD_WUNLOCK(d);
1632 			CURVNET_RESTORE();
1633 			return (EBUSY);
1634 		}
1635 		d->bd_bufmode = *(u_int *)addr;
1636 		BPFD_WUNLOCK(d);
1637 		break;
1638 
1639 	case BIOCGETZMAX:
1640 		error = bpf_ioctl_getzmax(td, d, (size_t *)addr);
1641 		break;
1642 
1643 	case BIOCSETZBUF:
1644 		error = bpf_ioctl_setzbuf(td, d, (struct bpf_zbuf *)addr);
1645 		break;
1646 
1647 	case BIOCROTZBUF:
1648 		error = bpf_ioctl_rotzbuf(td, d, (struct bpf_zbuf *)addr);
1649 		break;
1650 	}
1651 	CURVNET_RESTORE();
1652 	return (error);
1653 }
1654 
1655 /*
1656  * Set d's packet filter program to fp.  If this file already has a filter,
1657  * free it and replace it.  Returns EINVAL for bogus requests.
1658  */
1659 static int
1660 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
1661 {
1662 	struct bpf_insn *fcode, *old;
1663 	u_int wfilter, flen, size;
1664 #ifdef BPF_JITTER
1665 	bpf_jit_filter *ofunc;
1666 #endif
1667 	int need_upgrade;
1668 #ifdef COMPAT_FREEBSD32
1669 	struct bpf_program32 *fp32;
1670 	struct bpf_program fp_swab;
1671 
1672 	if (cmd == BIOCSETWF32 || cmd == BIOCSETF32 || cmd == BIOCSETFNR32) {
1673 		fp32 = (struct bpf_program32 *)fp;
1674 		fp_swab.bf_len = fp32->bf_len;
1675 		fp_swab.bf_insns = (struct bpf_insn *)(uintptr_t)fp32->bf_insns;
1676 		fp = &fp_swab;
1677 		if (cmd == BIOCSETWF32)
1678 			cmd = BIOCSETWF;
1679 	}
1680 #endif
1681 	/*
1682 	 * Check new filter validness before acquiring any locks.
1683 	 * Allocate memory for new filter, if needed.
1684 	 */
1685 	flen = fp->bf_len;
1686 	if ((flen > bpf_maxinsns) || ((fp->bf_insns == NULL) && (flen != 0)))
1687 		return (EINVAL);
1688 
1689 	need_upgrade = 0;
1690 	size = flen * sizeof(*fp->bf_insns);
1691 	if (size > 0)
1692 		fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK);
1693 	else
1694 		fcode = NULL; /* Make compiler happy */
1695 
1696 	BPF_LOCK();
1697 
1698 	if (cmd == BIOCSETWF) {
1699 		old = d->bd_wfilter;
1700 		wfilter = 1;
1701 #ifdef BPF_JITTER
1702 		ofunc = NULL;
1703 #endif
1704 	} else {
1705 		wfilter = 0;
1706 		old = d->bd_rfilter;
1707 #ifdef BPF_JITTER
1708 		ofunc = d->bd_bfilter;
1709 #endif
1710 	}
1711 	if (fp->bf_insns == NULL) {
1712 		/*
1713 		 * Protect filter removal by interface lock.
1714 		 * Additionally, we are protected by global lock here.
1715 		 */
1716 		if (d->bd_bif != NULL)
1717 			BPFIF_WLOCK(d->bd_bif);
1718 		BPFD_WLOCK(d);
1719 		if (wfilter)
1720 			d->bd_wfilter = NULL;
1721 		else {
1722 			d->bd_rfilter = NULL;
1723 #ifdef BPF_JITTER
1724 			d->bd_bfilter = NULL;
1725 #endif
1726 			if (cmd == BIOCSETF)
1727 				reset_d(d);
1728 		}
1729 		BPFD_WUNLOCK(d);
1730 		if (d->bd_bif != NULL)
1731 			BPFIF_WUNLOCK(d->bd_bif);
1732 		if (old != NULL)
1733 			free((caddr_t)old, M_BPF);
1734 #ifdef BPF_JITTER
1735 		if (ofunc != NULL)
1736 			bpf_destroy_jit_filter(ofunc);
1737 #endif
1738 		BPF_UNLOCK();
1739 		return (0);
1740 	}
1741 
1742 	if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 &&
1743 	    bpf_validate(fcode, (int)flen)) {
1744 		/*
1745 		 * Protect filter change by interface lock
1746 		 * Additionally, we are protected by global lock here.
1747 		 */
1748 		if (d->bd_bif != NULL)
1749 			BPFIF_WLOCK(d->bd_bif);
1750 		BPFD_WLOCK(d);
1751 		if (wfilter)
1752 			d->bd_wfilter = fcode;
1753 		else {
1754 			d->bd_rfilter = fcode;
1755 #ifdef BPF_JITTER
1756 			d->bd_bfilter = bpf_jitter(fcode, flen);
1757 #endif
1758 			if (cmd == BIOCSETF)
1759 				reset_d(d);
1760 
1761 			/*
1762 			 * Do not require upgrade by first BIOCSETF
1763 			 * (used to set snaplen) by pcap_open_live()
1764 			 */
1765 			if ((d->bd_writer != 0) && (--d->bd_writer == 0))
1766 				need_upgrade = 1;
1767 			CTR4(KTR_NET, "%s: filter function set by pid %d, "
1768 			    "bd_writer counter %d, need_upgrade %d",
1769 			    __func__, d->bd_pid, d->bd_writer, need_upgrade);
1770 		}
1771 		BPFD_WUNLOCK(d);
1772 		if (d->bd_bif != NULL)
1773 			BPFIF_WUNLOCK(d->bd_bif);
1774 		if (old != NULL)
1775 			free((caddr_t)old, M_BPF);
1776 #ifdef BPF_JITTER
1777 		if (ofunc != NULL)
1778 			bpf_destroy_jit_filter(ofunc);
1779 #endif
1780 
1781 		/* Move d to active readers list */
1782 		if (need_upgrade != 0)
1783 			bpf_upgraded(d);
1784 
1785 		BPF_UNLOCK();
1786 		return (0);
1787 	}
1788 	free((caddr_t)fcode, M_BPF);
1789 	BPF_UNLOCK();
1790 	return (EINVAL);
1791 }
1792 
1793 /*
1794  * Detach a file from its current interface (if attached at all) and attach
1795  * to the interface indicated by the name stored in ifr.
1796  * Return an errno or 0.
1797  */
1798 static int
1799 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
1800 {
1801 	struct bpf_if *bp;
1802 	struct ifnet *theywant;
1803 
1804 	BPF_LOCK_ASSERT();
1805 
1806 	theywant = ifunit(ifr->ifr_name);
1807 	if (theywant == NULL || theywant->if_bpf == NULL)
1808 		return (ENXIO);
1809 
1810 	bp = theywant->if_bpf;
1811 
1812 	/*
1813 	 * Behavior here depends on the buffering model.  If we're using
1814 	 * kernel memory buffers, then we can allocate them here.  If we're
1815 	 * using zero-copy, then the user process must have registered
1816 	 * buffers by the time we get here.  If not, return an error.
1817 	 *
1818 	 * XXXRW: There are locking issues here with multi-threaded use: what
1819 	 * if two threads try to set the interface at once?
1820 	 */
1821 	switch (d->bd_bufmode) {
1822 	case BPF_BUFMODE_BUFFER:
1823 		if (d->bd_sbuf == NULL)
1824 			bpf_buffer_alloc(d);
1825 		KASSERT(d->bd_sbuf != NULL, ("bpf_setif: bd_sbuf NULL"));
1826 		break;
1827 
1828 	case BPF_BUFMODE_ZBUF:
1829 		if (d->bd_sbuf == NULL)
1830 			return (EINVAL);
1831 		break;
1832 
1833 	default:
1834 		panic("bpf_setif: bufmode %d", d->bd_bufmode);
1835 	}
1836 	if (bp != d->bd_bif)
1837 		bpf_attachd(d, bp);
1838 	BPFD_WLOCK(d);
1839 	reset_d(d);
1840 	BPFD_WUNLOCK(d);
1841 	return (0);
1842 }
1843 
1844 /*
1845  * Support for select() and poll() system calls
1846  *
1847  * Return true iff the specific operation will not block indefinitely.
1848  * Otherwise, return false but make a note that a selwakeup() must be done.
1849  */
1850 static int
1851 bpfpoll(struct cdev *dev, int events, struct thread *td)
1852 {
1853 	struct bpf_d *d;
1854 	int revents;
1855 
1856 	if (devfs_get_cdevpriv((void **)&d) != 0 || d->bd_bif == NULL)
1857 		return (events &
1858 		    (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
1859 
1860 	/*
1861 	 * Refresh PID associated with this descriptor.
1862 	 */
1863 	revents = events & (POLLOUT | POLLWRNORM);
1864 	BPFD_WLOCK(d);
1865 	BPF_PID_REFRESH(d, td);
1866 	if (events & (POLLIN | POLLRDNORM)) {
1867 		if (bpf_ready(d))
1868 			revents |= events & (POLLIN | POLLRDNORM);
1869 		else {
1870 			selrecord(td, &d->bd_sel);
1871 			/* Start the read timeout if necessary. */
1872 			if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1873 				callout_reset(&d->bd_callout, d->bd_rtout,
1874 				    bpf_timed_out, d);
1875 				d->bd_state = BPF_WAITING;
1876 			}
1877 		}
1878 	}
1879 	BPFD_WUNLOCK(d);
1880 	return (revents);
1881 }
1882 
1883 /*
1884  * Support for kevent() system call.  Register EVFILT_READ filters and
1885  * reject all others.
1886  */
1887 int
1888 bpfkqfilter(struct cdev *dev, struct knote *kn)
1889 {
1890 	struct bpf_d *d;
1891 
1892 	if (devfs_get_cdevpriv((void **)&d) != 0 ||
1893 	    kn->kn_filter != EVFILT_READ)
1894 		return (1);
1895 
1896 	/*
1897 	 * Refresh PID associated with this descriptor.
1898 	 */
1899 	BPFD_WLOCK(d);
1900 	BPF_PID_REFRESH_CUR(d);
1901 	kn->kn_fop = &bpfread_filtops;
1902 	kn->kn_hook = d;
1903 	knlist_add(&d->bd_sel.si_note, kn, 1);
1904 	BPFD_WUNLOCK(d);
1905 
1906 	return (0);
1907 }
1908 
1909 static void
1910 filt_bpfdetach(struct knote *kn)
1911 {
1912 	struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
1913 
1914 	knlist_remove(&d->bd_sel.si_note, kn, 0);
1915 }
1916 
1917 static int
1918 filt_bpfread(struct knote *kn, long hint)
1919 {
1920 	struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
1921 	int ready;
1922 
1923 	BPFD_WLOCK_ASSERT(d);
1924 	ready = bpf_ready(d);
1925 	if (ready) {
1926 		kn->kn_data = d->bd_slen;
1927 		if (d->bd_hbuf)
1928 			kn->kn_data += d->bd_hlen;
1929 	} else if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1930 		callout_reset(&d->bd_callout, d->bd_rtout,
1931 		    bpf_timed_out, d);
1932 		d->bd_state = BPF_WAITING;
1933 	}
1934 
1935 	return (ready);
1936 }
1937 
1938 #define	BPF_TSTAMP_NONE		0
1939 #define	BPF_TSTAMP_FAST		1
1940 #define	BPF_TSTAMP_NORMAL	2
1941 #define	BPF_TSTAMP_EXTERN	3
1942 
1943 static int
1944 bpf_ts_quality(int tstype)
1945 {
1946 
1947 	if (tstype == BPF_T_NONE)
1948 		return (BPF_TSTAMP_NONE);
1949 	if ((tstype & BPF_T_FAST) != 0)
1950 		return (BPF_TSTAMP_FAST);
1951 
1952 	return (BPF_TSTAMP_NORMAL);
1953 }
1954 
1955 static int
1956 bpf_gettime(struct bintime *bt, int tstype, struct mbuf *m)
1957 {
1958 	struct m_tag *tag;
1959 	int quality;
1960 
1961 	quality = bpf_ts_quality(tstype);
1962 	if (quality == BPF_TSTAMP_NONE)
1963 		return (quality);
1964 
1965 	if (m != NULL) {
1966 		tag = m_tag_locate(m, MTAG_BPF, MTAG_BPF_TIMESTAMP, NULL);
1967 		if (tag != NULL) {
1968 			*bt = *(struct bintime *)(tag + 1);
1969 			return (BPF_TSTAMP_EXTERN);
1970 		}
1971 	}
1972 	if (quality == BPF_TSTAMP_NORMAL)
1973 		binuptime(bt);
1974 	else
1975 		getbinuptime(bt);
1976 
1977 	return (quality);
1978 }
1979 
1980 /*
1981  * Incoming linkage from device drivers.  Process the packet pkt, of length
1982  * pktlen, which is stored in a contiguous buffer.  The packet is parsed
1983  * by each process' filter, and if accepted, stashed into the corresponding
1984  * buffer.
1985  */
1986 void
1987 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1988 {
1989 	struct bintime bt;
1990 	struct bpf_d *d;
1991 #ifdef BPF_JITTER
1992 	bpf_jit_filter *bf;
1993 #endif
1994 	u_int slen;
1995 	int gottime;
1996 
1997 	gottime = BPF_TSTAMP_NONE;
1998 
1999 	BPFIF_RLOCK(bp);
2000 
2001 	LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
2002 		/*
2003 		 * We are not using any locks for d here because:
2004 		 * 1) any filter change is protected by interface
2005 		 * write lock
2006 		 * 2) destroying/detaching d is protected by interface
2007 		 * write lock, too
2008 		 */
2009 
2010 		/* XXX: Do not protect counter for the sake of performance. */
2011 		++d->bd_rcount;
2012 		/*
2013 		 * NB: We dont call BPF_CHECK_DIRECTION() here since there is no
2014 		 * way for the caller to indiciate to us whether this packet
2015 		 * is inbound or outbound.  In the bpf_mtap() routines, we use
2016 		 * the interface pointers on the mbuf to figure it out.
2017 		 */
2018 #ifdef BPF_JITTER
2019 		bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL;
2020 		if (bf != NULL)
2021 			slen = (*(bf->func))(pkt, pktlen, pktlen);
2022 		else
2023 #endif
2024 		slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
2025 		if (slen != 0) {
2026 			/*
2027 			 * Filter matches. Let's to acquire write lock.
2028 			 */
2029 			BPFD_WLOCK(d);
2030 
2031 			d->bd_fcount++;
2032 			if (gottime < bpf_ts_quality(d->bd_tstamp))
2033 				gottime = bpf_gettime(&bt, d->bd_tstamp, NULL);
2034 #ifdef MAC
2035 			if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
2036 #endif
2037 				catchpacket(d, pkt, pktlen, slen,
2038 				    bpf_append_bytes, &bt);
2039 			BPFD_WUNLOCK(d);
2040 		}
2041 	}
2042 	BPFIF_RUNLOCK(bp);
2043 }
2044 
2045 #define	BPF_CHECK_DIRECTION(d, r, i)				\
2046 	    (((d)->bd_direction == BPF_D_IN && (r) != (i)) ||	\
2047 	    ((d)->bd_direction == BPF_D_OUT && (r) == (i)))
2048 
2049 /*
2050  * Incoming linkage from device drivers, when packet is in an mbuf chain.
2051  * Locking model is explained in bpf_tap().
2052  */
2053 void
2054 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
2055 {
2056 	struct bintime bt;
2057 	struct bpf_d *d;
2058 #ifdef BPF_JITTER
2059 	bpf_jit_filter *bf;
2060 #endif
2061 	u_int pktlen, slen;
2062 	int gottime;
2063 
2064 	/* Skip outgoing duplicate packets. */
2065 	if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) {
2066 		m->m_flags &= ~M_PROMISC;
2067 		return;
2068 	}
2069 
2070 	pktlen = m_length(m, NULL);
2071 	gottime = BPF_TSTAMP_NONE;
2072 
2073 	BPFIF_RLOCK(bp);
2074 
2075 	LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
2076 		if (BPF_CHECK_DIRECTION(d, m->m_pkthdr.rcvif, bp->bif_ifp))
2077 			continue;
2078 		++d->bd_rcount;
2079 #ifdef BPF_JITTER
2080 		bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL;
2081 		/* XXX We cannot handle multiple mbufs. */
2082 		if (bf != NULL && m->m_next == NULL)
2083 			slen = (*(bf->func))(mtod(m, u_char *), pktlen, pktlen);
2084 		else
2085 #endif
2086 		slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
2087 		if (slen != 0) {
2088 			BPFD_WLOCK(d);
2089 
2090 			d->bd_fcount++;
2091 			if (gottime < bpf_ts_quality(d->bd_tstamp))
2092 				gottime = bpf_gettime(&bt, d->bd_tstamp, m);
2093 #ifdef MAC
2094 			if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
2095 #endif
2096 				catchpacket(d, (u_char *)m, pktlen, slen,
2097 				    bpf_append_mbuf, &bt);
2098 			BPFD_WUNLOCK(d);
2099 		}
2100 	}
2101 	BPFIF_RUNLOCK(bp);
2102 }
2103 
2104 /*
2105  * Incoming linkage from device drivers, when packet is in
2106  * an mbuf chain and to be prepended by a contiguous header.
2107  */
2108 void
2109 bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m)
2110 {
2111 	struct bintime bt;
2112 	struct mbuf mb;
2113 	struct bpf_d *d;
2114 	u_int pktlen, slen;
2115 	int gottime;
2116 
2117 	/* Skip outgoing duplicate packets. */
2118 	if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) {
2119 		m->m_flags &= ~M_PROMISC;
2120 		return;
2121 	}
2122 
2123 	pktlen = m_length(m, NULL);
2124 	/*
2125 	 * Craft on-stack mbuf suitable for passing to bpf_filter.
2126 	 * Note that we cut corners here; we only setup what's
2127 	 * absolutely needed--this mbuf should never go anywhere else.
2128 	 */
2129 	mb.m_next = m;
2130 	mb.m_data = data;
2131 	mb.m_len = dlen;
2132 	pktlen += dlen;
2133 
2134 	gottime = BPF_TSTAMP_NONE;
2135 
2136 	BPFIF_RLOCK(bp);
2137 
2138 	LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
2139 		if (BPF_CHECK_DIRECTION(d, m->m_pkthdr.rcvif, bp->bif_ifp))
2140 			continue;
2141 		++d->bd_rcount;
2142 		slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0);
2143 		if (slen != 0) {
2144 			BPFD_WLOCK(d);
2145 
2146 			d->bd_fcount++;
2147 			if (gottime < bpf_ts_quality(d->bd_tstamp))
2148 				gottime = bpf_gettime(&bt, d->bd_tstamp, m);
2149 #ifdef MAC
2150 			if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
2151 #endif
2152 				catchpacket(d, (u_char *)&mb, pktlen, slen,
2153 				    bpf_append_mbuf, &bt);
2154 			BPFD_WUNLOCK(d);
2155 		}
2156 	}
2157 	BPFIF_RUNLOCK(bp);
2158 }
2159 
2160 #undef	BPF_CHECK_DIRECTION
2161 
2162 #undef	BPF_TSTAMP_NONE
2163 #undef	BPF_TSTAMP_FAST
2164 #undef	BPF_TSTAMP_NORMAL
2165 #undef	BPF_TSTAMP_EXTERN
2166 
2167 static int
2168 bpf_hdrlen(struct bpf_d *d)
2169 {
2170 	int hdrlen;
2171 
2172 	hdrlen = d->bd_bif->bif_hdrlen;
2173 #ifndef BURN_BRIDGES
2174 	if (d->bd_tstamp == BPF_T_NONE ||
2175 	    BPF_T_FORMAT(d->bd_tstamp) == BPF_T_MICROTIME)
2176 #ifdef COMPAT_FREEBSD32
2177 		if (d->bd_compat32)
2178 			hdrlen += SIZEOF_BPF_HDR(struct bpf_hdr32);
2179 		else
2180 #endif
2181 			hdrlen += SIZEOF_BPF_HDR(struct bpf_hdr);
2182 	else
2183 #endif
2184 		hdrlen += SIZEOF_BPF_HDR(struct bpf_xhdr);
2185 #ifdef COMPAT_FREEBSD32
2186 	if (d->bd_compat32)
2187 		hdrlen = BPF_WORDALIGN32(hdrlen);
2188 	else
2189 #endif
2190 		hdrlen = BPF_WORDALIGN(hdrlen);
2191 
2192 	return (hdrlen - d->bd_bif->bif_hdrlen);
2193 }
2194 
2195 static void
2196 bpf_bintime2ts(struct bintime *bt, struct bpf_ts *ts, int tstype)
2197 {
2198 	struct bintime bt2;
2199 	struct timeval tsm;
2200 	struct timespec tsn;
2201 
2202 	if ((tstype & BPF_T_MONOTONIC) == 0) {
2203 		bt2 = *bt;
2204 		bintime_add(&bt2, &boottimebin);
2205 		bt = &bt2;
2206 	}
2207 	switch (BPF_T_FORMAT(tstype)) {
2208 	case BPF_T_MICROTIME:
2209 		bintime2timeval(bt, &tsm);
2210 		ts->bt_sec = tsm.tv_sec;
2211 		ts->bt_frac = tsm.tv_usec;
2212 		break;
2213 	case BPF_T_NANOTIME:
2214 		bintime2timespec(bt, &tsn);
2215 		ts->bt_sec = tsn.tv_sec;
2216 		ts->bt_frac = tsn.tv_nsec;
2217 		break;
2218 	case BPF_T_BINTIME:
2219 		ts->bt_sec = bt->sec;
2220 		ts->bt_frac = bt->frac;
2221 		break;
2222 	}
2223 }
2224 
2225 /*
2226  * Move the packet data from interface memory (pkt) into the
2227  * store buffer.  "cpfn" is the routine called to do the actual data
2228  * transfer.  bcopy is passed in to copy contiguous chunks, while
2229  * bpf_append_mbuf is passed in to copy mbuf chains.  In the latter case,
2230  * pkt is really an mbuf.
2231  */
2232 static void
2233 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
2234     void (*cpfn)(struct bpf_d *, caddr_t, u_int, void *, u_int),
2235     struct bintime *bt)
2236 {
2237 	struct bpf_xhdr hdr;
2238 #ifndef BURN_BRIDGES
2239 	struct bpf_hdr hdr_old;
2240 #ifdef COMPAT_FREEBSD32
2241 	struct bpf_hdr32 hdr32_old;
2242 #endif
2243 #endif
2244 	int caplen, curlen, hdrlen, totlen;
2245 	int do_wakeup = 0;
2246 	int do_timestamp;
2247 	int tstype;
2248 
2249 	BPFD_WLOCK_ASSERT(d);
2250 
2251 	/*
2252 	 * Detect whether user space has released a buffer back to us, and if
2253 	 * so, move it from being a hold buffer to a free buffer.  This may
2254 	 * not be the best place to do it (for example, we might only want to
2255 	 * run this check if we need the space), but for now it's a reliable
2256 	 * spot to do it.
2257 	 */
2258 	if (d->bd_fbuf == NULL && bpf_canfreebuf(d)) {
2259 		d->bd_fbuf = d->bd_hbuf;
2260 		d->bd_hbuf = NULL;
2261 		d->bd_hlen = 0;
2262 		bpf_buf_reclaimed(d);
2263 	}
2264 
2265 	/*
2266 	 * Figure out how many bytes to move.  If the packet is
2267 	 * greater or equal to the snapshot length, transfer that
2268 	 * much.  Otherwise, transfer the whole packet (unless
2269 	 * we hit the buffer size limit).
2270 	 */
2271 	hdrlen = bpf_hdrlen(d);
2272 	totlen = hdrlen + min(snaplen, pktlen);
2273 	if (totlen > d->bd_bufsize)
2274 		totlen = d->bd_bufsize;
2275 
2276 	/*
2277 	 * Round up the end of the previous packet to the next longword.
2278 	 *
2279 	 * Drop the packet if there's no room and no hope of room
2280 	 * If the packet would overflow the storage buffer or the storage
2281 	 * buffer is considered immutable by the buffer model, try to rotate
2282 	 * the buffer and wakeup pending processes.
2283 	 */
2284 #ifdef COMPAT_FREEBSD32
2285 	if (d->bd_compat32)
2286 		curlen = BPF_WORDALIGN32(d->bd_slen);
2287 	else
2288 #endif
2289 		curlen = BPF_WORDALIGN(d->bd_slen);
2290 	if (curlen + totlen > d->bd_bufsize || !bpf_canwritebuf(d)) {
2291 		if (d->bd_fbuf == NULL) {
2292 			/*
2293 			 * There's no room in the store buffer, and no
2294 			 * prospect of room, so drop the packet.  Notify the
2295 			 * buffer model.
2296 			 */
2297 			bpf_buffull(d);
2298 			++d->bd_dcount;
2299 			return;
2300 		}
2301 		ROTATE_BUFFERS(d);
2302 		do_wakeup = 1;
2303 		curlen = 0;
2304 	} else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
2305 		/*
2306 		 * Immediate mode is set, or the read timeout has already
2307 		 * expired during a select call.  A packet arrived, so the
2308 		 * reader should be woken up.
2309 		 */
2310 		do_wakeup = 1;
2311 	caplen = totlen - hdrlen;
2312 	tstype = d->bd_tstamp;
2313 	do_timestamp = tstype != BPF_T_NONE;
2314 #ifndef BURN_BRIDGES
2315 	if (tstype == BPF_T_NONE || BPF_T_FORMAT(tstype) == BPF_T_MICROTIME) {
2316 		struct bpf_ts ts;
2317 		if (do_timestamp)
2318 			bpf_bintime2ts(bt, &ts, tstype);
2319 #ifdef COMPAT_FREEBSD32
2320 		if (d->bd_compat32) {
2321 			bzero(&hdr32_old, sizeof(hdr32_old));
2322 			if (do_timestamp) {
2323 				hdr32_old.bh_tstamp.tv_sec = ts.bt_sec;
2324 				hdr32_old.bh_tstamp.tv_usec = ts.bt_frac;
2325 			}
2326 			hdr32_old.bh_datalen = pktlen;
2327 			hdr32_old.bh_hdrlen = hdrlen;
2328 			hdr32_old.bh_caplen = caplen;
2329 			bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr32_old,
2330 			    sizeof(hdr32_old));
2331 			goto copy;
2332 		}
2333 #endif
2334 		bzero(&hdr_old, sizeof(hdr_old));
2335 		if (do_timestamp) {
2336 			hdr_old.bh_tstamp.tv_sec = ts.bt_sec;
2337 			hdr_old.bh_tstamp.tv_usec = ts.bt_frac;
2338 		}
2339 		hdr_old.bh_datalen = pktlen;
2340 		hdr_old.bh_hdrlen = hdrlen;
2341 		hdr_old.bh_caplen = caplen;
2342 		bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr_old,
2343 		    sizeof(hdr_old));
2344 		goto copy;
2345 	}
2346 #endif
2347 
2348 	/*
2349 	 * Append the bpf header.  Note we append the actual header size, but
2350 	 * move forward the length of the header plus padding.
2351 	 */
2352 	bzero(&hdr, sizeof(hdr));
2353 	if (do_timestamp)
2354 		bpf_bintime2ts(bt, &hdr.bh_tstamp, tstype);
2355 	hdr.bh_datalen = pktlen;
2356 	hdr.bh_hdrlen = hdrlen;
2357 	hdr.bh_caplen = caplen;
2358 	bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr, sizeof(hdr));
2359 
2360 	/*
2361 	 * Copy the packet data into the store buffer and update its length.
2362 	 */
2363 #ifndef BURN_BRIDGES
2364 copy:
2365 #endif
2366 	(*cpfn)(d, d->bd_sbuf, curlen + hdrlen, pkt, caplen);
2367 	d->bd_slen = curlen + totlen;
2368 
2369 	if (do_wakeup)
2370 		bpf_wakeup(d);
2371 }
2372 
2373 /*
2374  * Free buffers currently in use by a descriptor.
2375  * Called on close.
2376  */
2377 static void
2378 bpf_freed(struct bpf_d *d)
2379 {
2380 
2381 	/*
2382 	 * We don't need to lock out interrupts since this descriptor has
2383 	 * been detached from its interface and it yet hasn't been marked
2384 	 * free.
2385 	 */
2386 	bpf_free(d);
2387 	if (d->bd_rfilter != NULL) {
2388 		free((caddr_t)d->bd_rfilter, M_BPF);
2389 #ifdef BPF_JITTER
2390 		if (d->bd_bfilter != NULL)
2391 			bpf_destroy_jit_filter(d->bd_bfilter);
2392 #endif
2393 	}
2394 	if (d->bd_wfilter != NULL)
2395 		free((caddr_t)d->bd_wfilter, M_BPF);
2396 	rw_destroy(&d->bd_lock);
2397 }
2398 
2399 /*
2400  * Attach an interface to bpf.  dlt is the link layer type; hdrlen is the
2401  * fixed size of the link header (variable length headers not yet supported).
2402  */
2403 void
2404 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
2405 {
2406 
2407 	bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf);
2408 }
2409 
2410 /*
2411  * Attach an interface to bpf.  ifp is a pointer to the structure
2412  * defining the interface to be attached, dlt is the link layer type,
2413  * and hdrlen is the fixed size of the link header (variable length
2414  * headers are not yet supporrted).
2415  */
2416 void
2417 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
2418 {
2419 	struct bpf_if *bp;
2420 
2421 	bp = malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO);
2422 	if (bp == NULL)
2423 		panic("bpfattach");
2424 
2425 	LIST_INIT(&bp->bif_dlist);
2426 	LIST_INIT(&bp->bif_wlist);
2427 	bp->bif_ifp = ifp;
2428 	bp->bif_dlt = dlt;
2429 	rw_init(&bp->bif_lock, "bpf interface lock");
2430 	KASSERT(*driverp == NULL, ("bpfattach2: driverp already initialized"));
2431 	*driverp = bp;
2432 
2433 	BPF_LOCK();
2434 	LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next);
2435 	BPF_UNLOCK();
2436 
2437 	bp->bif_hdrlen = hdrlen;
2438 
2439 	if (bootverbose)
2440 		if_printf(ifp, "bpf attached\n");
2441 }
2442 
2443 /*
2444  * Detach bpf from an interface. This involves detaching each descriptor
2445  * associated with the interface. Notify each descriptor as it's detached
2446  * so that any sleepers wake up and get ENXIO.
2447  */
2448 void
2449 bpfdetach(struct ifnet *ifp)
2450 {
2451 	struct bpf_if	*bp;
2452 	struct bpf_d	*d;
2453 #ifdef INVARIANTS
2454 	int ndetached;
2455 
2456 	ndetached = 0;
2457 #endif
2458 
2459 	/* Find all bpf_if struct's which reference ifp and detach them. */
2460 	do {
2461 		BPF_LOCK();
2462 		LIST_FOREACH(bp, &bpf_iflist, bif_next) {
2463 			if (ifp == bp->bif_ifp)
2464 				break;
2465 		}
2466 		if (bp != NULL)
2467 			LIST_REMOVE(bp, bif_next);
2468 		BPF_UNLOCK();
2469 
2470 		if (bp != NULL) {
2471 #ifdef INVARIANTS
2472 			ndetached++;
2473 #endif
2474 			while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
2475 				bpf_detachd(d);
2476 				BPFD_WLOCK(d);
2477 				bpf_wakeup(d);
2478 				BPFD_WUNLOCK(d);
2479 			}
2480 			/* Free writer-only descriptors */
2481 			while ((d = LIST_FIRST(&bp->bif_wlist)) != NULL) {
2482 				bpf_detachd(d);
2483 				BPFD_WLOCK(d);
2484 				bpf_wakeup(d);
2485 				BPFD_WUNLOCK(d);
2486 			}
2487 			rw_destroy(&bp->bif_lock);
2488 			free(bp, M_BPF);
2489 		}
2490 	} while (bp != NULL);
2491 
2492 #ifdef INVARIANTS
2493 	if (ndetached == 0)
2494 		printf("bpfdetach: %s was not attached\n", ifp->if_xname);
2495 #endif
2496 }
2497 
2498 /*
2499  * Get a list of available data link type of the interface.
2500  */
2501 static int
2502 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
2503 {
2504 	int n, error;
2505 	struct ifnet *ifp;
2506 	struct bpf_if *bp;
2507 
2508 	ifp = d->bd_bif->bif_ifp;
2509 	n = 0;
2510 	error = 0;
2511 	BPF_LOCK();
2512 	LIST_FOREACH(bp, &bpf_iflist, bif_next) {
2513 		if (bp->bif_ifp != ifp)
2514 			continue;
2515 		if (bfl->bfl_list != NULL) {
2516 			if (n >= bfl->bfl_len) {
2517 				BPF_UNLOCK();
2518 				return (ENOMEM);
2519 			}
2520 			error = copyout(&bp->bif_dlt,
2521 			    bfl->bfl_list + n, sizeof(u_int));
2522 		}
2523 		n++;
2524 	}
2525 	BPF_UNLOCK();
2526 	bfl->bfl_len = n;
2527 	return (error);
2528 }
2529 
2530 /*
2531  * Set the data link type of a BPF instance.
2532  */
2533 static int
2534 bpf_setdlt(struct bpf_d *d, u_int dlt)
2535 {
2536 	int error, opromisc;
2537 	struct ifnet *ifp;
2538 	struct bpf_if *bp;
2539 
2540 	BPF_LOCK_ASSERT();
2541 
2542 	if (d->bd_bif->bif_dlt == dlt)
2543 		return (0);
2544 	ifp = d->bd_bif->bif_ifp;
2545 
2546 	LIST_FOREACH(bp, &bpf_iflist, bif_next) {
2547 		if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
2548 			break;
2549 	}
2550 
2551 	if (bp != NULL) {
2552 		opromisc = d->bd_promisc;
2553 		bpf_attachd(d, bp);
2554 		BPFD_WLOCK(d);
2555 		reset_d(d);
2556 		BPFD_WUNLOCK(d);
2557 		if (opromisc) {
2558 			error = ifpromisc(bp->bif_ifp, 1);
2559 			if (error)
2560 				if_printf(bp->bif_ifp,
2561 					"bpf_setdlt: ifpromisc failed (%d)\n",
2562 					error);
2563 			else
2564 				d->bd_promisc = 1;
2565 		}
2566 	}
2567 	return (bp == NULL ? EINVAL : 0);
2568 }
2569 
2570 static void
2571 bpf_drvinit(void *unused)
2572 {
2573 	struct cdev *dev;
2574 
2575 	mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF);
2576 	LIST_INIT(&bpf_iflist);
2577 
2578 	dev = make_dev(&bpf_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "bpf");
2579 	/* For compatibility */
2580 	make_dev_alias(dev, "bpf0");
2581 }
2582 
2583 /*
2584  * Zero out the various packet counters associated with all of the bpf
2585  * descriptors.  At some point, we will probably want to get a bit more
2586  * granular and allow the user to specify descriptors to be zeroed.
2587  */
2588 static void
2589 bpf_zero_counters(void)
2590 {
2591 	struct bpf_if *bp;
2592 	struct bpf_d *bd;
2593 
2594 	BPF_LOCK();
2595 	LIST_FOREACH(bp, &bpf_iflist, bif_next) {
2596 		BPFIF_RLOCK(bp);
2597 		LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
2598 			BPFD_WLOCK(bd);
2599 			bd->bd_rcount = 0;
2600 			bd->bd_dcount = 0;
2601 			bd->bd_fcount = 0;
2602 			bd->bd_wcount = 0;
2603 			bd->bd_wfcount = 0;
2604 			bd->bd_zcopy = 0;
2605 			BPFD_WUNLOCK(bd);
2606 		}
2607 		BPFIF_RUNLOCK(bp);
2608 	}
2609 	BPF_UNLOCK();
2610 }
2611 
2612 /*
2613  * Fill filter statistics
2614  */
2615 static void
2616 bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd)
2617 {
2618 
2619 	bzero(d, sizeof(*d));
2620 	BPFD_LOCK_ASSERT(bd);
2621 	d->bd_structsize = sizeof(*d);
2622 	/* XXX: reading should be protected by global lock */
2623 	d->bd_immediate = bd->bd_immediate;
2624 	d->bd_promisc = bd->bd_promisc;
2625 	d->bd_hdrcmplt = bd->bd_hdrcmplt;
2626 	d->bd_direction = bd->bd_direction;
2627 	d->bd_feedback = bd->bd_feedback;
2628 	d->bd_async = bd->bd_async;
2629 	d->bd_rcount = bd->bd_rcount;
2630 	d->bd_dcount = bd->bd_dcount;
2631 	d->bd_fcount = bd->bd_fcount;
2632 	d->bd_sig = bd->bd_sig;
2633 	d->bd_slen = bd->bd_slen;
2634 	d->bd_hlen = bd->bd_hlen;
2635 	d->bd_bufsize = bd->bd_bufsize;
2636 	d->bd_pid = bd->bd_pid;
2637 	strlcpy(d->bd_ifname,
2638 	    bd->bd_bif->bif_ifp->if_xname, IFNAMSIZ);
2639 	d->bd_locked = bd->bd_locked;
2640 	d->bd_wcount = bd->bd_wcount;
2641 	d->bd_wdcount = bd->bd_wdcount;
2642 	d->bd_wfcount = bd->bd_wfcount;
2643 	d->bd_zcopy = bd->bd_zcopy;
2644 	d->bd_bufmode = bd->bd_bufmode;
2645 }
2646 
2647 /*
2648  * Handle `netstat -B' stats request
2649  */
2650 static int
2651 bpf_stats_sysctl(SYSCTL_HANDLER_ARGS)
2652 {
2653 	struct xbpf_d *xbdbuf, *xbd, zerostats;
2654 	int index, error;
2655 	struct bpf_if *bp;
2656 	struct bpf_d *bd;
2657 
2658 	/*
2659 	 * XXX This is not technically correct. It is possible for non
2660 	 * privileged users to open bpf devices. It would make sense
2661 	 * if the users who opened the devices were able to retrieve
2662 	 * the statistics for them, too.
2663 	 */
2664 	error = priv_check(req->td, PRIV_NET_BPF);
2665 	if (error)
2666 		return (error);
2667 	/*
2668 	 * Check to see if the user is requesting that the counters be
2669 	 * zeroed out.  Explicitly check that the supplied data is zeroed,
2670 	 * as we aren't allowing the user to set the counters currently.
2671 	 */
2672 	if (req->newptr != NULL) {
2673 		if (req->newlen != sizeof(zerostats))
2674 			return (EINVAL);
2675 		bzero(&zerostats, sizeof(zerostats));
2676 		xbd = req->newptr;
2677 		if (bcmp(xbd, &zerostats, sizeof(*xbd)) != 0)
2678 			return (EINVAL);
2679 		bpf_zero_counters();
2680 		return (0);
2681 	}
2682 	if (req->oldptr == NULL)
2683 		return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd)));
2684 	if (bpf_bpfd_cnt == 0)
2685 		return (SYSCTL_OUT(req, 0, 0));
2686 	xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK);
2687 	BPF_LOCK();
2688 	if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) {
2689 		BPF_UNLOCK();
2690 		free(xbdbuf, M_BPF);
2691 		return (ENOMEM);
2692 	}
2693 	index = 0;
2694 	LIST_FOREACH(bp, &bpf_iflist, bif_next) {
2695 		BPFIF_RLOCK(bp);
2696 		/* Send writers-only first */
2697 		LIST_FOREACH(bd, &bp->bif_wlist, bd_next) {
2698 			xbd = &xbdbuf[index++];
2699 			BPFD_RLOCK(bd);
2700 			bpfstats_fill_xbpf(xbd, bd);
2701 			BPFD_RUNLOCK(bd);
2702 		}
2703 		LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
2704 			xbd = &xbdbuf[index++];
2705 			BPFD_RLOCK(bd);
2706 			bpfstats_fill_xbpf(xbd, bd);
2707 			BPFD_RUNLOCK(bd);
2708 		}
2709 		BPFIF_RUNLOCK(bp);
2710 	}
2711 	BPF_UNLOCK();
2712 	error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd));
2713 	free(xbdbuf, M_BPF);
2714 	return (error);
2715 }
2716 
2717 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,bpf_drvinit,NULL);
2718 
2719 #else /* !DEV_BPF && !NETGRAPH_BPF */
2720 /*
2721  * NOP stubs to allow bpf-using drivers to load and function.
2722  *
2723  * A 'better' implementation would allow the core bpf functionality
2724  * to be loaded at runtime.
2725  */
2726 static struct bpf_if bp_null;
2727 
2728 void
2729 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
2730 {
2731 }
2732 
2733 void
2734 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
2735 {
2736 }
2737 
2738 void
2739 bpf_mtap2(struct bpf_if *bp, void *d, u_int l, struct mbuf *m)
2740 {
2741 }
2742 
2743 void
2744 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
2745 {
2746 
2747 	bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf);
2748 }
2749 
2750 void
2751 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
2752 {
2753 
2754 	*driverp = &bp_null;
2755 }
2756 
2757 void
2758 bpfdetach(struct ifnet *ifp)
2759 {
2760 }
2761 
2762 u_int
2763 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
2764 {
2765 	return -1;	/* "no filter" behaviour */
2766 }
2767 
2768 int
2769 bpf_validate(const struct bpf_insn *f, int len)
2770 {
2771 	return 0;		/* false */
2772 }
2773 
2774 #endif /* !DEV_BPF && !NETGRAPH_BPF */
2775