bpf.c revision 1.109 1 /* $NetBSD: bpf.c,v 1.109 2005/06/22 10:36:16 peter Exp $ */
2
3 /*
4 * Copyright (c) 1990, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from the Stanford/CMU enet packet filter,
8 * (net/enet.c) distributed as part of 4.3BSD, and code contributed
9 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
10 * Berkeley Laboratory.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)bpf.c 8.4 (Berkeley) 1/9/95
37 * static char rcsid[] =
38 * "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp ";
39 */
40
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.109 2005/06/22 10:36:16 peter Exp $");
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/mbuf.h>
47 #include <sys/buf.h>
48 #include <sys/time.h>
49 #include <sys/proc.h>
50 #include <sys/user.h>
51 #include <sys/ioctl.h>
52 #include <sys/conf.h>
53 #include <sys/vnode.h>
54 #include <sys/queue.h>
55
56 #include <sys/file.h>
57 #include <sys/filedesc.h>
58 #include <sys/tty.h>
59 #include <sys/uio.h>
60
61 #include <sys/protosw.h>
62 #include <sys/socket.h>
63 #include <sys/errno.h>
64 #include <sys/kernel.h>
65 #include <sys/poll.h>
66 #include <sys/sysctl.h>
67
68 #include <net/if.h>
69 #include <net/slip.h>
70
71 #include <net/bpf.h>
72 #include <net/bpfdesc.h>
73
74 #include <net/if_arc.h>
75 #include <net/if_ether.h>
76
77 #include <netinet/in.h>
78 #include <netinet/if_inarp.h>
79
80 #if defined(_KERNEL_OPT)
81 #include "opt_bpf.h"
82 #include "sl.h"
83 #include "strip.h"
84 #endif
85
86 #ifndef BPF_BUFSIZE
87 /*
88 * 4096 is too small for FDDI frames. 8192 is too small for gigabit Ethernet
89 * jumbos (circa 9k), ATM, or Intel gig/10gig ethernet jumbos (16k).
90 */
91 # define BPF_BUFSIZE 32768
92 #endif
93
94 #define PRINET 26 /* interruptible */
95
96 /*
97 * The default read buffer size, and limit for BIOCSBLEN, is sysctl'able.
98 * XXX the default values should be computed dynamically based
99 * on available memory size and available mbuf clusters.
100 */
101 int bpf_bufsize = BPF_BUFSIZE;
102 int bpf_maxbufsize = BPF_DFLTBUFSIZE; /* XXX set dynamically, see above */
103
104 /*
105 * bpf_iflist is the list of interfaces; each corresponds to an ifnet
106 * bpf_dtab holds the descriptors, indexed by minor device #
107 */
108 struct bpf_if *bpf_iflist;
109 LIST_HEAD(, bpf_d) bpf_list;
110
111 static int bpf_allocbufs(struct bpf_d *);
112 static void bpf_deliver(struct bpf_if *,
113 void *(*cpfn)(void *, const void *, size_t),
114 void *, u_int, u_int, struct ifnet *);
115 static void bpf_freed(struct bpf_d *);
116 static void bpf_ifname(struct ifnet *, struct ifreq *);
117 static void *bpf_mcpy(void *, const void *, size_t);
118 static int bpf_movein(struct uio *, int, int,
119 struct mbuf **, struct sockaddr *);
120 static void bpf_attachd(struct bpf_d *, struct bpf_if *);
121 static void bpf_detachd(struct bpf_d *);
122 static int bpf_setif(struct bpf_d *, struct ifreq *);
123 static void bpf_timed_out(void *);
124 static __inline void
125 bpf_wakeup(struct bpf_d *);
126 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
127 void *(*)(void *, const void *, size_t));
128 static void reset_d(struct bpf_d *);
129 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
130 static int bpf_setdlt(struct bpf_d *, u_int);
131
132 static int bpf_read(struct file *, off_t *, struct uio *, struct ucred *,
133 int);
134 static int bpf_write(struct file *, off_t *, struct uio *, struct ucred *,
135 int);
136 static int bpf_ioctl(struct file *, u_long, void *, struct proc *);
137 static int bpf_poll(struct file *, int, struct proc *);
138 static int bpf_close(struct file *, struct proc *);
139 static int bpf_kqfilter(struct file *, struct knote *);
140
141 static const struct fileops bpf_fileops = {
142 bpf_read,
143 bpf_write,
144 bpf_ioctl,
145 fnullop_fcntl,
146 bpf_poll,
147 fbadop_stat,
148 bpf_close,
149 bpf_kqfilter,
150 };
151
152 dev_type_open(bpfopen);
153
154 const struct cdevsw bpf_cdevsw = {
155 bpfopen, noclose, noread, nowrite, noioctl,
156 nostop, notty, nopoll, nommap, nokqfilter,
157 };
158
159 static int
160 bpf_movein(uio, linktype, mtu, mp, sockp)
161 struct uio *uio;
162 int linktype;
163 int mtu;
164 struct mbuf **mp;
165 struct sockaddr *sockp;
166 {
167 struct mbuf *m;
168 int error;
169 int len;
170 int hlen;
171 int align;
172
173 /*
174 * Build a sockaddr based on the data link layer type.
175 * We do this at this level because the ethernet header
176 * is copied directly into the data field of the sockaddr.
177 * In the case of SLIP, there is no header and the packet
178 * is forwarded as is.
179 * Also, we are careful to leave room at the front of the mbuf
180 * for the link level header.
181 */
182 switch (linktype) {
183
184 case DLT_SLIP:
185 sockp->sa_family = AF_INET;
186 hlen = 0;
187 align = 0;
188 break;
189
190 case DLT_PPP:
191 sockp->sa_family = AF_UNSPEC;
192 hlen = 0;
193 align = 0;
194 break;
195
196 case DLT_EN10MB:
197 sockp->sa_family = AF_UNSPEC;
198 /* XXX Would MAXLINKHDR be better? */
199 /* 6(dst)+6(src)+2(type) */
200 hlen = sizeof(struct ether_header);
201 align = 2;
202 break;
203
204 case DLT_ARCNET:
205 sockp->sa_family = AF_UNSPEC;
206 hlen = ARC_HDRLEN;
207 align = 5;
208 break;
209
210 case DLT_FDDI:
211 sockp->sa_family = AF_LINK;
212 /* XXX 4(FORMAC)+6(dst)+6(src) */
213 hlen = 16;
214 align = 0;
215 break;
216
217 case DLT_ECONET:
218 sockp->sa_family = AF_UNSPEC;
219 hlen = 6;
220 align = 2;
221 break;
222
223 case DLT_NULL:
224 sockp->sa_family = AF_UNSPEC;
225 hlen = 0;
226 align = 0;
227 break;
228
229 default:
230 return (EIO);
231 }
232
233 len = uio->uio_resid;
234 /*
235 * If there aren't enough bytes for a link level header or the
236 * packet length exceeds the interface mtu, return an error.
237 */
238 if (len < hlen || len - hlen > mtu)
239 return (EMSGSIZE);
240
241 /*
242 * XXX Avoid complicated buffer chaining ---
243 * bail if it won't fit in a single mbuf.
244 * (Take into account possible alignment bytes)
245 */
246 if ((unsigned)len > MCLBYTES - align)
247 return (EIO);
248
249 m = m_gethdr(M_WAIT, MT_DATA);
250 m->m_pkthdr.rcvif = 0;
251 m->m_pkthdr.len = len - hlen;
252 if (len > MHLEN - align) {
253 m_clget(m, M_WAIT);
254 if ((m->m_flags & M_EXT) == 0) {
255 error = ENOBUFS;
256 goto bad;
257 }
258 }
259
260 /* Insure the data is properly aligned */
261 if (align > 0) {
262 m->m_data += align;
263 m->m_len -= align;
264 }
265
266 error = uiomove(mtod(m, void *), len, uio);
267 if (error)
268 goto bad;
269 if (hlen != 0) {
270 memcpy(sockp->sa_data, mtod(m, void *), hlen);
271 m->m_data += hlen; /* XXX */
272 len -= hlen;
273 }
274 m->m_len = len;
275 *mp = m;
276 return (0);
277
278 bad:
279 m_freem(m);
280 return (error);
281 }
282
283 /*
284 * Attach file to the bpf interface, i.e. make d listen on bp.
285 * Must be called at splnet.
286 */
287 static void
288 bpf_attachd(d, bp)
289 struct bpf_d *d;
290 struct bpf_if *bp;
291 {
292 /*
293 * Point d at bp, and add d to the interface's list of listeners.
294 * Finally, point the driver's bpf cookie at the interface so
295 * it will divert packets to bpf.
296 */
297 d->bd_bif = bp;
298 d->bd_next = bp->bif_dlist;
299 bp->bif_dlist = d;
300
301 *bp->bif_driverp = bp;
302 }
303
304 /*
305 * Detach a file from its interface.
306 */
307 static void
308 bpf_detachd(d)
309 struct bpf_d *d;
310 {
311 struct bpf_d **p;
312 struct bpf_if *bp;
313
314 bp = d->bd_bif;
315 /*
316 * Check if this descriptor had requested promiscuous mode.
317 * If so, turn it off.
318 */
319 if (d->bd_promisc) {
320 int error;
321
322 d->bd_promisc = 0;
323 /*
324 * Take device out of promiscuous mode. Since we were
325 * able to enter promiscuous mode, we should be able
326 * to turn it off. But we can get an error if
327 * the interface was configured down, so only panic
328 * if we don't get an unexpected error.
329 */
330 error = ifpromisc(bp->bif_ifp, 0);
331 if (error && error != EINVAL)
332 panic("bpf: ifpromisc failed");
333 }
334 /* Remove d from the interface's descriptor list. */
335 p = &bp->bif_dlist;
336 while (*p != d) {
337 p = &(*p)->bd_next;
338 if (*p == 0)
339 panic("bpf_detachd: descriptor not in list");
340 }
341 *p = (*p)->bd_next;
342 if (bp->bif_dlist == 0)
343 /*
344 * Let the driver know that there are no more listeners.
345 */
346 *d->bd_bif->bif_driverp = 0;
347 d->bd_bif = 0;
348 }
349
350
351 /*
352 * Mark a descriptor free by making it point to itself.
353 * This is probably cheaper than marking with a constant since
354 * the address should be in a register anyway.
355 */
356
357 /*
358 * bpfilterattach() is called at boot time.
359 */
360 /* ARGSUSED */
361 void
362 bpfilterattach(n)
363 int n;
364 {
365 LIST_INIT(&bpf_list);
366 }
367
368 /*
369 * Open ethernet device. Clones.
370 */
371 /* ARGSUSED */
372 int
373 bpfopen(dev, flag, mode, p)
374 dev_t dev;
375 int flag;
376 int mode;
377 struct proc *p;
378 {
379 struct bpf_d *d;
380 struct file *fp;
381 int error, fd;
382
383 /* falloc() will use the descriptor for us. */
384 if ((error = falloc(p, &fp, &fd)) != 0)
385 return error;
386
387 d = malloc(sizeof(*d), M_DEVBUF, M_WAITOK);
388 (void)memset(d, 0, sizeof(*d));
389 d->bd_bufsize = bpf_bufsize;
390 d->bd_seesent = 1;
391 callout_init(&d->bd_callout);
392
393 LIST_INSERT_HEAD(&bpf_list, d, bd_list);
394
395 return fdclone(p, fp, fd, flag, &bpf_fileops, d);
396 }
397
398 /*
399 * Close the descriptor by detaching it from its interface,
400 * deallocating its buffers, and marking it free.
401 */
402 /* ARGSUSED */
403 static int
404 bpf_close(struct file *fp, struct proc *p)
405 {
406 struct bpf_d *d = fp->f_data;
407 int s;
408
409 s = splnet();
410 if (d->bd_state == BPF_WAITING)
411 callout_stop(&d->bd_callout);
412 d->bd_state = BPF_IDLE;
413 if (d->bd_bif)
414 bpf_detachd(d);
415 splx(s);
416 bpf_freed(d);
417 LIST_REMOVE(d, bd_list);
418 free(d, M_DEVBUF);
419 fp->f_data = NULL;
420
421 return (0);
422 }
423
424 /*
425 * Rotate the packet buffers in descriptor d. Move the store buffer
426 * into the hold slot, and the free buffer into the store slot.
427 * Zero the length of the new store buffer.
428 */
429 #define ROTATE_BUFFERS(d) \
430 (d)->bd_hbuf = (d)->bd_sbuf; \
431 (d)->bd_hlen = (d)->bd_slen; \
432 (d)->bd_sbuf = (d)->bd_fbuf; \
433 (d)->bd_slen = 0; \
434 (d)->bd_fbuf = 0;
435 /*
436 * bpfread - read next chunk of packets from buffers
437 */
438 static int
439 bpf_read(struct file *fp, off_t *offp, struct uio *uio,
440 struct ucred *cred, int flags)
441 {
442 struct bpf_d *d = fp->f_data;
443 int timed_out;
444 int error;
445 int s;
446
447 /*
448 * Restrict application to use a buffer the same size as
449 * as kernel buffers.
450 */
451 if (uio->uio_resid != d->bd_bufsize)
452 return (EINVAL);
453
454 s = splnet();
455 if (d->bd_state == BPF_WAITING)
456 callout_stop(&d->bd_callout);
457 timed_out = (d->bd_state == BPF_TIMED_OUT);
458 d->bd_state = BPF_IDLE;
459 /*
460 * If the hold buffer is empty, then do a timed sleep, which
461 * ends when the timeout expires or when enough packets
462 * have arrived to fill the store buffer.
463 */
464 while (d->bd_hbuf == 0) {
465 if (fp->f_flag & FNONBLOCK) {
466 if (d->bd_slen == 0) {
467 splx(s);
468 return (EWOULDBLOCK);
469 }
470 ROTATE_BUFFERS(d);
471 break;
472 }
473
474 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
475 /*
476 * A packet(s) either arrived since the previous
477 * read or arrived while we were asleep.
478 * Rotate the buffers and return what's here.
479 */
480 ROTATE_BUFFERS(d);
481 break;
482 }
483 error = tsleep(d, PRINET|PCATCH, "bpf",
484 d->bd_rtout);
485 if (error == EINTR || error == ERESTART) {
486 splx(s);
487 return (error);
488 }
489 if (error == EWOULDBLOCK) {
490 /*
491 * On a timeout, return what's in the buffer,
492 * which may be nothing. If there is something
493 * in the store buffer, we can rotate the buffers.
494 */
495 if (d->bd_hbuf)
496 /*
497 * We filled up the buffer in between
498 * getting the timeout and arriving
499 * here, so we don't need to rotate.
500 */
501 break;
502
503 if (d->bd_slen == 0) {
504 splx(s);
505 return (0);
506 }
507 ROTATE_BUFFERS(d);
508 break;
509 }
510 if (error != 0)
511 goto done;
512 }
513 /*
514 * At this point, we know we have something in the hold slot.
515 */
516 splx(s);
517
518 /*
519 * Move data from hold buffer into user space.
520 * We know the entire buffer is transferred since
521 * we checked above that the read buffer is bpf_bufsize bytes.
522 */
523 error = uiomove(d->bd_hbuf, d->bd_hlen, uio);
524
525 s = splnet();
526 d->bd_fbuf = d->bd_hbuf;
527 d->bd_hbuf = 0;
528 d->bd_hlen = 0;
529 done:
530 splx(s);
531 return (error);
532 }
533
534
535 /*
536 * If there are processes sleeping on this descriptor, wake them up.
537 */
538 static __inline void
539 bpf_wakeup(d)
540 struct bpf_d *d;
541 {
542 wakeup(d);
543 if (d->bd_async)
544 fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL);
545
546 selnotify(&d->bd_sel, 0);
547 /* XXX */
548 d->bd_sel.sel_pid = 0;
549 }
550
551
552 static void
553 bpf_timed_out(arg)
554 void *arg;
555 {
556 struct bpf_d *d = arg;
557 int s;
558
559 s = splnet();
560 if (d->bd_state == BPF_WAITING) {
561 d->bd_state = BPF_TIMED_OUT;
562 if (d->bd_slen != 0)
563 bpf_wakeup(d);
564 }
565 splx(s);
566 }
567
568
569 static int
570 bpf_write(struct file *fp, off_t *offp, struct uio *uio,
571 struct ucred *cred, int flags)
572 {
573 struct bpf_d *d = fp->f_data;
574 struct ifnet *ifp;
575 struct mbuf *m;
576 int error, s;
577 static struct sockaddr_storage dst;
578
579 if (d->bd_bif == 0)
580 return (ENXIO);
581
582 ifp = d->bd_bif->bif_ifp;
583
584 if (uio->uio_resid == 0)
585 return (0);
586
587 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, &m,
588 (struct sockaddr *) &dst);
589 if (error)
590 return (error);
591
592 if (m->m_pkthdr.len > ifp->if_mtu) {
593 m_freem(m);
594 return (EMSGSIZE);
595 }
596
597 if (d->bd_hdrcmplt)
598 dst.ss_family = pseudo_AF_HDRCMPLT;
599
600 s = splsoftnet();
601 error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL);
602 splx(s);
603 /*
604 * The driver frees the mbuf.
605 */
606 return (error);
607 }
608
609 /*
610 * Reset a descriptor by flushing its packet buffer and clearing the
611 * receive and drop counts. Should be called at splnet.
612 */
613 static void
614 reset_d(d)
615 struct bpf_d *d;
616 {
617 if (d->bd_hbuf) {
618 /* Free the hold buffer. */
619 d->bd_fbuf = d->bd_hbuf;
620 d->bd_hbuf = 0;
621 }
622 d->bd_slen = 0;
623 d->bd_hlen = 0;
624 d->bd_rcount = 0;
625 d->bd_dcount = 0;
626 d->bd_ccount = 0;
627 }
628
629 #ifdef BPF_KERN_FILTER
630 extern struct bpf_insn *bpf_tcp_filter;
631 extern struct bpf_insn *bpf_udp_filter;
632 #endif
633
634 /*
635 * FIONREAD Check for read packet available.
636 * BIOCGBLEN Get buffer len [for read()].
637 * BIOCSETF Set ethernet read filter.
638 * BIOCFLUSH Flush read packet buffer.
639 * BIOCPROMISC Put interface into promiscuous mode.
640 * BIOCGDLT Get link layer type.
641 * BIOCGETIF Get interface name.
642 * BIOCSETIF Set interface.
643 * BIOCSRTIMEOUT Set read timeout.
644 * BIOCGRTIMEOUT Get read timeout.
645 * BIOCGSTATS Get packet stats.
646 * BIOCIMMEDIATE Set immediate mode.
647 * BIOCVERSION Get filter language version.
648 * BIOGHDRCMPLT Get "header already complete" flag.
649 * BIOSHDRCMPLT Set "header already complete" flag.
650 */
651 /* ARGSUSED */
652 static int
653 bpf_ioctl(struct file *fp, u_long cmd, void *addr, struct proc *p)
654 {
655 struct bpf_d *d = fp->f_data;
656 int s, error = 0;
657 #ifdef BPF_KERN_FILTER
658 struct bpf_insn **p;
659 #endif
660
661 s = splnet();
662 if (d->bd_state == BPF_WAITING)
663 callout_stop(&d->bd_callout);
664 d->bd_state = BPF_IDLE;
665 splx(s);
666
667 switch (cmd) {
668
669 default:
670 error = EINVAL;
671 break;
672
673 /*
674 * Check for read packet available.
675 */
676 case FIONREAD:
677 {
678 int n;
679
680 s = splnet();
681 n = d->bd_slen;
682 if (d->bd_hbuf)
683 n += d->bd_hlen;
684 splx(s);
685
686 *(int *)addr = n;
687 break;
688 }
689
690 /*
691 * Get buffer len [for read()].
692 */
693 case BIOCGBLEN:
694 *(u_int *)addr = d->bd_bufsize;
695 break;
696
697 /*
698 * Set buffer length.
699 */
700 case BIOCSBLEN:
701 if (d->bd_bif != 0)
702 error = EINVAL;
703 else {
704 u_int size = *(u_int *)addr;
705
706 if (size > bpf_maxbufsize)
707 *(u_int *)addr = size = bpf_maxbufsize;
708 else if (size < BPF_MINBUFSIZE)
709 *(u_int *)addr = size = BPF_MINBUFSIZE;
710 d->bd_bufsize = size;
711 }
712 break;
713
714 /*
715 * Set link layer read filter.
716 */
717 case BIOCSETF:
718 error = bpf_setf(d, addr);
719 break;
720
721 #ifdef BPF_KERN_FILTER
722 /*
723 * Set TCP or UDP reject filter.
724 */
725 case BIOCSTCPF:
726 case BIOCSUDPF:
727 if (!suser()) {
728 error = EPERM;
729 break;
730 }
731
732 /* Validate and store filter */
733 error = bpf_setf(d, addr);
734
735 /* Free possible old filter */
736 if (cmd == BIOCSTCPF)
737 p = &bpf_tcp_filter;
738 else
739 p = &bpf_udp_filter;
740 if (*p != NULL)
741 free(*p, M_DEVBUF);
742
743 /* Steal new filter (noop if error) */
744 s = splnet();
745 *p = d->bd_filter;
746 d->bd_filter = NULL;
747 splx(s);
748 break;
749 #endif
750
751 /*
752 * Flush read packet buffer.
753 */
754 case BIOCFLUSH:
755 s = splnet();
756 reset_d(d);
757 splx(s);
758 break;
759
760 /*
761 * Put interface into promiscuous mode.
762 */
763 case BIOCPROMISC:
764 if (d->bd_bif == 0) {
765 /*
766 * No interface attached yet.
767 */
768 error = EINVAL;
769 break;
770 }
771 s = splnet();
772 if (d->bd_promisc == 0) {
773 error = ifpromisc(d->bd_bif->bif_ifp, 1);
774 if (error == 0)
775 d->bd_promisc = 1;
776 }
777 splx(s);
778 break;
779
780 /*
781 * Get device parameters.
782 */
783 case BIOCGDLT:
784 if (d->bd_bif == 0)
785 error = EINVAL;
786 else
787 *(u_int *)addr = d->bd_bif->bif_dlt;
788 break;
789
790 /*
791 * Get a list of supported device parameters.
792 */
793 case BIOCGDLTLIST:
794 if (d->bd_bif == 0)
795 error = EINVAL;
796 else
797 error = bpf_getdltlist(d, addr);
798 break;
799
800 /*
801 * Set device parameters.
802 */
803 case BIOCSDLT:
804 if (d->bd_bif == 0)
805 error = EINVAL;
806 else
807 error = bpf_setdlt(d, *(u_int *)addr);
808 break;
809
810 /*
811 * Set interface name.
812 */
813 case BIOCGETIF:
814 if (d->bd_bif == 0)
815 error = EINVAL;
816 else
817 bpf_ifname(d->bd_bif->bif_ifp, addr);
818 break;
819
820 /*
821 * Set interface.
822 */
823 case BIOCSETIF:
824 error = bpf_setif(d, addr);
825 break;
826
827 /*
828 * Set read timeout.
829 */
830 case BIOCSRTIMEOUT:
831 {
832 struct timeval *tv = addr;
833
834 /* Compute number of ticks. */
835 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick;
836 if ((d->bd_rtout == 0) && (tv->tv_usec != 0))
837 d->bd_rtout = 1;
838 break;
839 }
840
841 /*
842 * Get read timeout.
843 */
844 case BIOCGRTIMEOUT:
845 {
846 struct timeval *tv = addr;
847
848 tv->tv_sec = d->bd_rtout / hz;
849 tv->tv_usec = (d->bd_rtout % hz) * tick;
850 break;
851 }
852
853 /*
854 * Get packet stats.
855 */
856 case BIOCGSTATS:
857 {
858 struct bpf_stat *bs = addr;
859
860 bs->bs_recv = d->bd_rcount;
861 bs->bs_drop = d->bd_dcount;
862 bs->bs_capt = d->bd_ccount;
863 break;
864 }
865
866 case BIOCGSTATSOLD:
867 {
868 struct bpf_stat_old *bs = addr;
869
870 bs->bs_recv = d->bd_rcount;
871 bs->bs_drop = d->bd_dcount;
872 break;
873 }
874
875 /*
876 * Set immediate mode.
877 */
878 case BIOCIMMEDIATE:
879 d->bd_immediate = *(u_int *)addr;
880 break;
881
882 case BIOCVERSION:
883 {
884 struct bpf_version *bv = addr;
885
886 bv->bv_major = BPF_MAJOR_VERSION;
887 bv->bv_minor = BPF_MINOR_VERSION;
888 break;
889 }
890
891 case BIOCGHDRCMPLT: /* get "header already complete" flag */
892 *(u_int *)addr = d->bd_hdrcmplt;
893 break;
894
895 case BIOCSHDRCMPLT: /* set "header already complete" flag */
896 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
897 break;
898
899 /*
900 * Get "see sent packets" flag
901 */
902 case BIOCGSEESENT:
903 *(u_int *)addr = d->bd_seesent;
904 break;
905
906 /*
907 * Set "see sent" packets flag
908 */
909 case BIOCSSEESENT:
910 d->bd_seesent = *(u_int *)addr;
911 break;
912
913 case FIONBIO: /* Non-blocking I/O */
914 /*
915 * No need to do anything special as we use IO_NDELAY in
916 * bpfread() as an indication of whether or not to block
917 * the read.
918 */
919 break;
920
921 case FIOASYNC: /* Send signal on receive packets */
922 d->bd_async = *(int *)addr;
923 break;
924
925 case TIOCSPGRP: /* Process or group to send signals to */
926 case FIOSETOWN:
927 error = fsetown(p, &d->bd_pgid, cmd, addr);
928 break;
929
930 case TIOCGPGRP:
931 case FIOGETOWN:
932 error = fgetown(p, d->bd_pgid, cmd, addr);
933 break;
934 }
935 return (error);
936 }
937
938 /*
939 * Set d's packet filter program to fp. If this file already has a filter,
940 * free it and replace it. Returns EINVAL for bogus requests.
941 */
942 int
943 bpf_setf(struct bpf_d *d, struct bpf_program *fp)
944 {
945 struct bpf_insn *fcode, *old;
946 u_int flen, size;
947 int s;
948
949 old = d->bd_filter;
950 if (fp->bf_insns == 0) {
951 if (fp->bf_len != 0)
952 return (EINVAL);
953 s = splnet();
954 d->bd_filter = 0;
955 reset_d(d);
956 splx(s);
957 if (old != 0)
958 free(old, M_DEVBUF);
959 return (0);
960 }
961 flen = fp->bf_len;
962 if (flen > BPF_MAXINSNS)
963 return (EINVAL);
964
965 size = flen * sizeof(*fp->bf_insns);
966 fcode = malloc(size, M_DEVBUF, M_WAITOK);
967 if (copyin(fp->bf_insns, fcode, size) == 0 &&
968 bpf_validate(fcode, (int)flen)) {
969 s = splnet();
970 d->bd_filter = fcode;
971 reset_d(d);
972 splx(s);
973 if (old != 0)
974 free(old, M_DEVBUF);
975
976 return (0);
977 }
978 free(fcode, M_DEVBUF);
979 return (EINVAL);
980 }
981
982 /*
983 * Detach a file from its current interface (if attached at all) and attach
984 * to the interface indicated by the name stored in ifr.
985 * Return an errno or 0.
986 */
987 static int
988 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
989 {
990 struct bpf_if *bp;
991 char *cp;
992 int unit_seen, i, s, error;
993
994 /*
995 * Make sure the provided name has a unit number, and default
996 * it to '0' if not specified.
997 * XXX This is ugly ... do this differently?
998 */
999 unit_seen = 0;
1000 cp = ifr->ifr_name;
1001 cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */
1002 while (*cp++)
1003 if (*cp >= '0' && *cp <= '9')
1004 unit_seen = 1;
1005 if (!unit_seen) {
1006 /* Make sure to leave room for the '\0'. */
1007 for (i = 0; i < (IFNAMSIZ - 1); ++i) {
1008 if ((ifr->ifr_name[i] >= 'a' &&
1009 ifr->ifr_name[i] <= 'z') ||
1010 (ifr->ifr_name[i] >= 'A' &&
1011 ifr->ifr_name[i] <= 'Z'))
1012 continue;
1013 ifr->ifr_name[i] = '0';
1014 }
1015 }
1016
1017 /*
1018 * Look through attached interfaces for the named one.
1019 */
1020 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
1021 struct ifnet *ifp = bp->bif_ifp;
1022
1023 if (ifp == 0 ||
1024 strcmp(ifp->if_xname, ifr->ifr_name) != 0)
1025 continue;
1026 /* skip additional entry */
1027 if (bp->bif_driverp != (struct bpf_if **)&ifp->if_bpf)
1028 continue;
1029 /*
1030 * We found the requested interface.
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 (d->bd_sbuf == 0) {
1036 error = bpf_allocbufs(d);
1037 if (error != 0)
1038 return (error);
1039 }
1040 s = splnet();
1041 if (bp != d->bd_bif) {
1042 if (d->bd_bif)
1043 /*
1044 * Detach if attached to something else.
1045 */
1046 bpf_detachd(d);
1047
1048 bpf_attachd(d, bp);
1049 }
1050 reset_d(d);
1051 splx(s);
1052 return (0);
1053 }
1054 /* Not found. */
1055 return (ENXIO);
1056 }
1057
1058 /*
1059 * Copy the interface name to the ifreq.
1060 */
1061 static void
1062 bpf_ifname(struct ifnet *ifp, struct ifreq *ifr)
1063 {
1064 memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
1065 }
1066
1067 /*
1068 * Support for poll() system call
1069 *
1070 * Return true iff the specific operation will not block indefinitely - with
1071 * the assumption that it is safe to positively acknowledge a request for the
1072 * ability to write to the BPF device.
1073 * Otherwise, return false but make a note that a selwakeup() must be done.
1074 */
1075 static int
1076 bpf_poll(struct file *fp, int events, struct proc *p)
1077 {
1078 struct bpf_d *d = fp->f_data;
1079 int s = splnet();
1080 int revents;
1081
1082 revents = events & (POLLOUT | POLLWRNORM);
1083 if (events & (POLLIN | POLLRDNORM)) {
1084 /*
1085 * An imitation of the FIONREAD ioctl code.
1086 */
1087 if ((d->bd_hlen != 0) ||
1088 (d->bd_immediate && d->bd_slen != 0)) {
1089 revents |= events & (POLLIN | POLLRDNORM);
1090 } else if (d->bd_state == BPF_TIMED_OUT) {
1091 if (d->bd_slen != 0)
1092 revents |= events & (POLLIN | POLLRDNORM);
1093 else
1094 revents |= events & POLLIN;
1095 } else {
1096 selrecord(p, &d->bd_sel);
1097 /* Start the read timeout if necessary */
1098 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1099 callout_reset(&d->bd_callout, d->bd_rtout,
1100 bpf_timed_out, d);
1101 d->bd_state = BPF_WAITING;
1102 }
1103 }
1104 }
1105
1106 splx(s);
1107 return (revents);
1108 }
1109
1110 static void
1111 filt_bpfrdetach(struct knote *kn)
1112 {
1113 struct bpf_d *d = kn->kn_hook;
1114 int s;
1115
1116 s = splnet();
1117 SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext);
1118 splx(s);
1119 }
1120
1121 static int
1122 filt_bpfread(struct knote *kn, long hint)
1123 {
1124 struct bpf_d *d = kn->kn_hook;
1125
1126 kn->kn_data = d->bd_hlen;
1127 if (d->bd_immediate)
1128 kn->kn_data += d->bd_slen;
1129 return (kn->kn_data > 0);
1130 }
1131
1132 static const struct filterops bpfread_filtops =
1133 { 1, NULL, filt_bpfrdetach, filt_bpfread };
1134
1135 static int
1136 bpf_kqfilter(struct file *fp, struct knote *kn)
1137 {
1138 struct bpf_d *d = fp->f_data;
1139 struct klist *klist;
1140 int s;
1141
1142 switch (kn->kn_filter) {
1143 case EVFILT_READ:
1144 klist = &d->bd_sel.sel_klist;
1145 kn->kn_fop = &bpfread_filtops;
1146 break;
1147
1148 default:
1149 return (1);
1150 }
1151
1152 kn->kn_hook = d;
1153
1154 s = splnet();
1155 SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1156 splx(s);
1157
1158 return (0);
1159 }
1160
1161 /*
1162 * Incoming linkage from device drivers. Process the packet pkt, of length
1163 * pktlen, which is stored in a contiguous buffer. The packet is parsed
1164 * by each process' filter, and if accepted, stashed into the corresponding
1165 * buffer.
1166 */
1167 void
1168 bpf_tap(void *arg, u_char *pkt, u_int pktlen)
1169 {
1170 struct bpf_if *bp;
1171 struct bpf_d *d;
1172 u_int slen;
1173 /*
1174 * Note that the ipl does not have to be raised at this point.
1175 * The only problem that could arise here is that if two different
1176 * interfaces shared any data. This is not the case.
1177 */
1178 bp = arg;
1179 for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
1180 ++d->bd_rcount;
1181 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
1182 if (slen != 0)
1183 catchpacket(d, pkt, pktlen, slen, memcpy);
1184 }
1185 }
1186
1187 /*
1188 * Copy data from an mbuf chain into a buffer. This code is derived
1189 * from m_copydata in sys/uipc_mbuf.c.
1190 */
1191 static void *
1192 bpf_mcpy(void *dst_arg, const void *src_arg, size_t len)
1193 {
1194 const struct mbuf *m;
1195 u_int count;
1196 u_char *dst;
1197
1198 m = src_arg;
1199 dst = dst_arg;
1200 while (len > 0) {
1201 if (m == 0)
1202 panic("bpf_mcpy");
1203 count = min(m->m_len, len);
1204 memcpy(dst, mtod(m, void *), count);
1205 m = m->m_next;
1206 dst += count;
1207 len -= count;
1208 }
1209 return (dst_arg);
1210 }
1211
1212 /*
1213 * Dispatch a packet to all the listeners on interface bp.
1214 *
1215 * marg pointer to the packet, either a data buffer or an mbuf chain
1216 * buflen buffer length, if marg is a data buffer
1217 * cpfn a function that can copy marg into the listener's buffer
1218 * pktlen length of the packet
1219 * rcvif either NULL or the interface the packet came in on.
1220 */
1221 static __inline void
1222 bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t),
1223 void *marg, u_int pktlen, u_int buflen, struct ifnet *rcvif)
1224 {
1225 u_int slen;
1226 struct bpf_d *d;
1227
1228 for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
1229 if (!d->bd_seesent && (rcvif == NULL))
1230 continue;
1231 ++d->bd_rcount;
1232 slen = bpf_filter(d->bd_filter, marg, pktlen, buflen);
1233 if (slen != 0)
1234 catchpacket(d, marg, pktlen, slen, cpfn);
1235 }
1236 }
1237
1238 /*
1239 * Incoming linkage from device drivers, when the head of the packet is in
1240 * a buffer, and the tail is in an mbuf chain.
1241 */
1242 void
1243 bpf_mtap2(void *arg, void *data, u_int dlen, struct mbuf *m)
1244 {
1245 struct bpf_if *bp = arg;
1246 u_int pktlen;
1247 struct mbuf mb;
1248
1249 pktlen = m_length(m) + dlen;
1250
1251 /*
1252 * Craft on-stack mbuf suitable for passing to bpf_filter.
1253 * Note that we cut corners here; we only setup what's
1254 * absolutely needed--this mbuf should never go anywhere else.
1255 */
1256 (void)memset(&mb, 0, sizeof(mb));
1257 mb.m_next = m;
1258 mb.m_data = data;
1259 mb.m_len = dlen;
1260
1261 bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif);
1262 }
1263
1264 /*
1265 * Incoming linkage from device drivers, when packet is in an mbuf chain.
1266 */
1267 void
1268 bpf_mtap(void *arg, struct mbuf *m)
1269 {
1270 void *(*cpfn)(void *, const void *, size_t);
1271 struct bpf_if *bp = arg;
1272 u_int pktlen, buflen;
1273 void *marg;
1274
1275 pktlen = m_length(m);
1276
1277 if (pktlen == m->m_len) {
1278 cpfn = memcpy;
1279 marg = mtod(m, void *);
1280 buflen = pktlen;
1281 } else {
1282 cpfn = bpf_mcpy;
1283 marg = m;
1284 buflen = 0;
1285 }
1286
1287 bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif);
1288 }
1289
1290 /*
1291 * We need to prepend the address family as
1292 * a four byte field. Cons up a dummy header
1293 * to pacify bpf. This is safe because bpf
1294 * will only read from the mbuf (i.e., it won't
1295 * try to free it or keep a pointer a to it).
1296 */
1297 void
1298 bpf_mtap_af(void *arg, u_int32_t af, struct mbuf *m)
1299 {
1300 struct mbuf m0;
1301
1302 m0.m_flags = 0;
1303 m0.m_next = m;
1304 m0.m_len = 4;
1305 m0.m_data = (char *)⁡
1306
1307 bpf_mtap(arg, &m0);
1308 }
1309
1310 void
1311 bpf_mtap_et(void *arg, u_int16_t et, struct mbuf *m)
1312 {
1313 struct mbuf m0;
1314
1315 m0.m_flags = 0;
1316 m0.m_next = m;
1317 m0.m_len = 14;
1318 m0.m_data = m0.m_dat;
1319
1320 ((u_int32_t *)m0.m_data)[0] = 0;
1321 ((u_int32_t *)m0.m_data)[1] = 0;
1322 ((u_int32_t *)m0.m_data)[2] = 0;
1323 ((u_int16_t *)m0.m_data)[6] = et;
1324
1325 bpf_mtap(arg, &m0);
1326 }
1327
1328 #if NSL > 0 || NSTRIP > 0
1329 /*
1330 * Put the SLIP pseudo-"link header" in place.
1331 * Note this M_PREPEND() should never fail,
1332 * swince we know we always have enough space
1333 * in the input buffer.
1334 */
1335 void
1336 bpf_mtap_sl_in(void *arg, u_char *chdr, struct mbuf **m)
1337 {
1338 int s;
1339 u_char *hp;
1340
1341 M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT);
1342 if (*m == NULL)
1343 return;
1344
1345 hp = mtod(*m, u_char *);
1346 hp[SLX_DIR] = SLIPDIR_IN;
1347 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
1348
1349 s = splnet();
1350 bpf_mtap(arg, *m);
1351 splx(s);
1352
1353 m_adj(*m, SLIP_HDRLEN);
1354 }
1355
1356 /*
1357 * Put the SLIP pseudo-"link header" in
1358 * place. The compressed header is now
1359 * at the beginning of the mbuf.
1360 */
1361 void
1362 bpf_mtap_sl_out(void *arg, u_char *chdr, struct mbuf *m)
1363 {
1364 struct mbuf m0;
1365 u_char *hp;
1366 int s;
1367
1368 m0.m_flags = 0;
1369 m0.m_next = m;
1370 m0.m_data = m0.m_dat;
1371 m0.m_len = SLIP_HDRLEN;
1372
1373 hp = mtod(&m0, u_char *);
1374
1375 hp[SLX_DIR] = SLIPDIR_OUT;
1376 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
1377
1378 s = splnet();
1379 bpf_mtap(arg, &m0);
1380 splx(s);
1381 m_freem(m);
1382 }
1383 #endif
1384
1385 /*
1386 * Move the packet data from interface memory (pkt) into the
1387 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1388 * otherwise 0. "copy" is the routine called to do the actual data
1389 * transfer. memcpy is passed in to copy contiguous chunks, while
1390 * bpf_mcpy is passed in to copy mbuf chains. In the latter case,
1391 * pkt is really an mbuf.
1392 */
1393 static void
1394 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1395 void *(*cpfn)(void *, const void *, size_t))
1396 {
1397 struct bpf_hdr *hp;
1398 int totlen, curlen;
1399 int hdrlen = d->bd_bif->bif_hdrlen;
1400
1401 ++d->bd_ccount;
1402 /*
1403 * Figure out how many bytes to move. If the packet is
1404 * greater or equal to the snapshot length, transfer that
1405 * much. Otherwise, transfer the whole packet (unless
1406 * we hit the buffer size limit).
1407 */
1408 totlen = hdrlen + min(snaplen, pktlen);
1409 if (totlen > d->bd_bufsize)
1410 totlen = d->bd_bufsize;
1411
1412 /*
1413 * Round up the end of the previous packet to the next longword.
1414 */
1415 curlen = BPF_WORDALIGN(d->bd_slen);
1416 if (curlen + totlen > d->bd_bufsize) {
1417 /*
1418 * This packet will overflow the storage buffer.
1419 * Rotate the buffers if we can, then wakeup any
1420 * pending reads.
1421 */
1422 if (d->bd_fbuf == 0) {
1423 /*
1424 * We haven't completed the previous read yet,
1425 * so drop the packet.
1426 */
1427 ++d->bd_dcount;
1428 return;
1429 }
1430 ROTATE_BUFFERS(d);
1431 bpf_wakeup(d);
1432 curlen = 0;
1433 }
1434
1435 /*
1436 * Append the bpf header.
1437 */
1438 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1439 microtime(&hp->bh_tstamp);
1440 hp->bh_datalen = pktlen;
1441 hp->bh_hdrlen = hdrlen;
1442 /*
1443 * Copy the packet data into the store buffer and update its length.
1444 */
1445 (*cpfn)((u_char *)hp + hdrlen, pkt, (hp->bh_caplen = totlen - hdrlen));
1446 d->bd_slen = curlen + totlen;
1447
1448 /*
1449 * Call bpf_wakeup after bd_slen has been updated so that kevent(2)
1450 * will cause filt_bpfread() to be called with it adjusted.
1451 */
1452 if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
1453 /*
1454 * Immediate mode is set, or the read timeout has
1455 * already expired during a select call. A packet
1456 * arrived, so the reader should be woken up.
1457 */
1458 bpf_wakeup(d);
1459 }
1460
1461 /*
1462 * Initialize all nonzero fields of a descriptor.
1463 */
1464 static int
1465 bpf_allocbufs(struct bpf_d *d)
1466 {
1467
1468 d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
1469 if (!d->bd_fbuf)
1470 return (ENOBUFS);
1471 d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
1472 if (!d->bd_sbuf) {
1473 free(d->bd_fbuf, M_DEVBUF);
1474 return (ENOBUFS);
1475 }
1476 d->bd_slen = 0;
1477 d->bd_hlen = 0;
1478 return (0);
1479 }
1480
1481 /*
1482 * Free buffers currently in use by a descriptor.
1483 * Called on close.
1484 */
1485 static void
1486 bpf_freed(struct bpf_d *d)
1487 {
1488 /*
1489 * We don't need to lock out interrupts since this descriptor has
1490 * been detached from its interface and it yet hasn't been marked
1491 * free.
1492 */
1493 if (d->bd_sbuf != 0) {
1494 free(d->bd_sbuf, M_DEVBUF);
1495 if (d->bd_hbuf != 0)
1496 free(d->bd_hbuf, M_DEVBUF);
1497 if (d->bd_fbuf != 0)
1498 free(d->bd_fbuf, M_DEVBUF);
1499 }
1500 if (d->bd_filter)
1501 free(d->bd_filter, M_DEVBUF);
1502 }
1503
1504 /*
1505 * Attach an interface to bpf. dlt is the link layer type; hdrlen is the
1506 * fixed size of the link header (variable length headers not yet supported).
1507 */
1508 void
1509 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1510 {
1511
1512 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf);
1513 }
1514
1515 /*
1516 * Attach additional dlt for a interface to bpf. dlt is the link layer type;
1517 * hdrlen is the fixed size of the link header for the specified dlt
1518 * (variable length headers not yet supported).
1519 */
1520 void
1521 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, void *driverp)
1522 {
1523 struct bpf_if *bp;
1524 bp = malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
1525 if (bp == 0)
1526 panic("bpfattach");
1527
1528 bp->bif_dlist = 0;
1529 bp->bif_driverp = driverp;
1530 bp->bif_ifp = ifp;
1531 bp->bif_dlt = dlt;
1532
1533 bp->bif_next = bpf_iflist;
1534 bpf_iflist = bp;
1535
1536 *bp->bif_driverp = 0;
1537
1538 /*
1539 * Compute the length of the bpf header. This is not necessarily
1540 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1541 * that the network layer header begins on a longword boundary (for
1542 * performance reasons and to alleviate alignment restrictions).
1543 */
1544 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1545
1546 #if 0
1547 printf("bpf: %s attached\n", ifp->if_xname);
1548 #endif
1549 }
1550
1551 /*
1552 * Remove an interface from bpf.
1553 */
1554 void
1555 bpfdetach(struct ifnet *ifp)
1556 {
1557 struct bpf_if *bp, **pbp;
1558 struct bpf_d *d;
1559 int s;
1560
1561 /* Nuke the vnodes for any open instances */
1562 for (d = LIST_FIRST(&bpf_list); d != NULL; d = LIST_NEXT(d, bd_list)) {
1563 if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) {
1564 /*
1565 * Detach the descriptor from an interface now.
1566 * It will be free'ed later by close routine.
1567 */
1568 s = splnet();
1569 d->bd_promisc = 0; /* we can't touch device. */
1570 bpf_detachd(d);
1571 splx(s);
1572 }
1573 }
1574
1575 again:
1576 for (bp = bpf_iflist, pbp = &bpf_iflist;
1577 bp != NULL; pbp = &bp->bif_next, bp = bp->bif_next) {
1578 if (bp->bif_ifp == ifp) {
1579 *pbp = bp->bif_next;
1580 free(bp, M_DEVBUF);
1581 goto again;
1582 }
1583 }
1584 }
1585
1586 /*
1587 * Change the data link type of a interface.
1588 */
1589 void
1590 bpf_change_type(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1591 {
1592 struct bpf_if *bp;
1593
1594 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1595 if (bp->bif_driverp == (struct bpf_if **)&ifp->if_bpf)
1596 break;
1597 }
1598 if (bp == NULL)
1599 panic("bpf_change_type");
1600
1601 bp->bif_dlt = dlt;
1602
1603 /*
1604 * Compute the length of the bpf header. This is not necessarily
1605 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1606 * that the network layer header begins on a longword boundary (for
1607 * performance reasons and to alleviate alignment restrictions).
1608 */
1609 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1610 }
1611
1612 /*
1613 * Get a list of available data link type of the interface.
1614 */
1615 static int
1616 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1617 {
1618 int n, error;
1619 struct ifnet *ifp;
1620 struct bpf_if *bp;
1621
1622 ifp = d->bd_bif->bif_ifp;
1623 n = 0;
1624 error = 0;
1625 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1626 if (bp->bif_ifp != ifp)
1627 continue;
1628 if (bfl->bfl_list != NULL) {
1629 if (n >= bfl->bfl_len)
1630 return ENOMEM;
1631 error = copyout(&bp->bif_dlt,
1632 bfl->bfl_list + n, sizeof(u_int));
1633 }
1634 n++;
1635 }
1636 bfl->bfl_len = n;
1637 return error;
1638 }
1639
1640 /*
1641 * Set the data link type of a BPF instance.
1642 */
1643 static int
1644 bpf_setdlt(struct bpf_d *d, u_int dlt)
1645 {
1646 int s, error, opromisc;
1647 struct ifnet *ifp;
1648 struct bpf_if *bp;
1649
1650 if (d->bd_bif->bif_dlt == dlt)
1651 return 0;
1652 ifp = d->bd_bif->bif_ifp;
1653 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1654 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1655 break;
1656 }
1657 if (bp == NULL)
1658 return EINVAL;
1659 s = splnet();
1660 opromisc = d->bd_promisc;
1661 bpf_detachd(d);
1662 bpf_attachd(d, bp);
1663 reset_d(d);
1664 if (opromisc) {
1665 error = ifpromisc(bp->bif_ifp, 1);
1666 if (error)
1667 printf("%s: bpf_setdlt: ifpromisc failed (%d)\n",
1668 bp->bif_ifp->if_xname, error);
1669 else
1670 d->bd_promisc = 1;
1671 }
1672 splx(s);
1673 return 0;
1674 }
1675
1676 static int
1677 sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS)
1678 {
1679 int newsize, error;
1680 struct sysctlnode node;
1681
1682 node = *rnode;
1683 node.sysctl_data = &newsize;
1684 newsize = bpf_maxbufsize;
1685 error = sysctl_lookup(SYSCTLFN_CALL(&node));
1686 if (error || newp == NULL)
1687 return (error);
1688
1689 if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE)
1690 return (EINVAL);
1691
1692 bpf_maxbufsize = newsize;
1693
1694 return (0);
1695 }
1696
1697 SYSCTL_SETUP(sysctl_net_bfp_setup, "sysctl net.bpf subtree setup")
1698 {
1699 const struct sysctlnode *node;
1700
1701 sysctl_createv(clog, 0, NULL, NULL,
1702 CTLFLAG_PERMANENT,
1703 CTLTYPE_NODE, "net", NULL,
1704 NULL, 0, NULL, 0,
1705 CTL_NET, CTL_EOL);
1706
1707 node = NULL;
1708 sysctl_createv(clog, 0, NULL, &node,
1709 CTLFLAG_PERMANENT,
1710 CTLTYPE_NODE, "bpf",
1711 SYSCTL_DESCR("BPF options"),
1712 NULL, 0, NULL, 0,
1713 CTL_NET, CTL_CREATE, CTL_EOL);
1714 if (node != NULL)
1715 sysctl_createv(clog, 0, NULL, NULL,
1716 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1717 CTLTYPE_INT, "maxbufsize",
1718 SYSCTL_DESCR("Maximum size for data capture buffer"),
1719 sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0,
1720 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
1721 }
1722