2 * Copyright (c) 1990, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
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
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)bpf.c 8.2 (Berkeley) 3/28/94
40 * $FreeBSD: src/sys/net/bpf.c,v 1.59.2.12 2002/04/14 21:41:48 luigi Exp $
41 * $DragonFly: src/sys/net/bpf.c,v 1.44 2008/03/14 09:52:10 matthias Exp $
46 #include <sys/param.h>
47 #include <sys/systm.h>
49 #include <sys/device.h>
50 #include <sys/malloc.h>
54 #include <sys/signalvar.h>
55 #include <sys/filio.h>
56 #include <sys/sockio.h>
57 #include <sys/ttycom.h>
58 #include <sys/filedesc.h>
62 #include <sys/socket.h>
63 #include <sys/vnode.h>
65 #include <sys/thread2.h>
69 #include <net/bpfdesc.h>
71 #include <netinet/in.h>
72 #include <netinet/if_ether.h>
73 #include <sys/kernel.h>
74 #include <sys/sysctl.h>
76 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
81 * The default read buffer size is patchable.
83 static int bpf_bufsize = BPF_DEFAULTBUFSIZE;
84 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
86 int bpf_maxbufsize = BPF_MAXBUFSIZE;
87 SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
88 &bpf_maxbufsize, 0, "");
91 * bpf_iflist is the list of interfaces; each corresponds to an ifnet
93 static struct bpf_if *bpf_iflist;
95 static int bpf_allocbufs(struct bpf_d *);
96 static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
97 static void bpf_detachd(struct bpf_d *d);
98 static void bpf_resetd(struct bpf_d *);
99 static void bpf_freed(struct bpf_d *);
100 static void bpf_mcopy(const void *, void *, size_t);
101 static int bpf_movein(struct uio *, int, struct mbuf **,
102 struct sockaddr *, int *, struct bpf_insn *);
103 static int bpf_setif(struct bpf_d *, struct ifreq *);
104 static void bpf_timed_out(void *);
105 static void bpf_wakeup(struct bpf_d *);
106 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
107 void (*)(const void *, void *, size_t),
108 const struct timeval *);
109 static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
110 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
111 static int bpf_setdlt(struct bpf_d *, u_int);
112 static void bpf_drvinit(void *unused);
114 static d_open_t bpfopen;
115 static d_close_t bpfclose;
116 static d_read_t bpfread;
117 static d_write_t bpfwrite;
118 static d_ioctl_t bpfioctl;
119 static d_poll_t bpfpoll;
121 #define CDEV_MAJOR 23
122 static struct dev_ops bpf_ops = {
123 { "bpf", CDEV_MAJOR, 0 },
134 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp,
135 struct sockaddr *sockp, int *datlen, struct bpf_insn *wfilter)
147 * Build a sockaddr based on the data link layer type.
148 * We do this at this level because the ethernet header
149 * is copied directly into the data field of the sockaddr.
150 * In the case of SLIP, there is no header and the packet
151 * is forwarded as is.
152 * Also, we are careful to leave room at the front of the mbuf
153 * for the link level header.
157 sockp->sa_family = AF_INET;
162 sockp->sa_family = AF_UNSPEC;
163 /* XXX Would MAXLINKHDR be better? */
164 hlen = sizeof(struct ether_header);
169 sockp->sa_family = AF_UNSPEC;
173 case DLT_ATM_RFC1483:
175 * en atm driver requires 4-byte atm pseudo header.
176 * though it isn't standard, vpi:vci needs to be
179 sockp->sa_family = AF_UNSPEC;
180 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
184 sockp->sa_family = AF_UNSPEC;
185 hlen = 4; /* This should match PPP_HDRLEN */
192 len = uio->uio_resid;
193 *datlen = len - hlen;
194 if ((unsigned)len > MCLBYTES)
197 m = m_getl(len, MB_WAIT, MT_DATA, M_PKTHDR, NULL);
200 m->m_pkthdr.len = m->m_len = len;
201 m->m_pkthdr.rcvif = NULL;
204 if (m->m_len < hlen) {
209 error = uiomove(mtod(m, u_char *), len, uio);
213 slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
220 * Make room for link header, and copy it to sockaddr.
223 bcopy(m->m_data, sockp->sa_data, hlen);
224 m->m_pkthdr.len -= hlen;
226 m->m_data += hlen; /* XXX */
235 * Attach file to the bpf interface, i.e. make d listen on bp.
236 * Must be called at splimp.
239 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
242 * Point d at bp, and add d to the interface's list of listeners.
243 * Finally, point the driver's bpf cookie at the interface so
244 * it will divert packets to bpf.
247 SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
248 *bp->bif_driverp = bp;
252 * Detach a file from its interface.
255 bpf_detachd(struct bpf_d *d)
264 /* Remove d from the interface's descriptor list. */
265 SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
267 if (SLIST_EMPTY(&bp->bif_dlist)) {
269 * Let the driver know that there are no more listeners.
271 *bp->bif_driverp = NULL;
275 * Check if this descriptor had requested promiscuous mode.
276 * If so, turn it off.
280 error = ifpromisc(ifp, 0);
281 if (error != 0 && error != ENXIO) {
283 * ENXIO can happen if a pccard is unplugged,
284 * Something is really wrong if we were able to put
285 * the driver into promiscuous mode, but can't
288 if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
295 * Open ethernet device. Returns ENXIO for illegal minor device number,
296 * EBUSY if file is open by another process.
300 bpfopen(struct dev_open_args *ap)
302 cdev_t dev = ap->a_head.a_dev;
305 if (ap->a_cred->cr_prison)
310 * Each minor can be opened by only one process. If the requested
311 * minor is in use, return EBUSY.
315 make_dev(&bpf_ops, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
316 MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
318 d->bd_bufsize = bpf_bufsize;
321 callout_init(&d->bd_callout);
326 * Close the descriptor by detaching it from its interface,
327 * deallocating its buffers, and marking it free.
331 bpfclose(struct dev_close_args *ap)
333 cdev_t dev = ap->a_head.a_dev;
334 struct bpf_d *d = dev->si_drv1;
336 funsetown(d->bd_sigio);
338 if (d->bd_state == BPF_WAITING)
339 callout_stop(&d->bd_callout);
340 d->bd_state = BPF_IDLE;
341 if (d->bd_bif != NULL)
352 * Rotate the packet buffers in descriptor d. Move the store buffer
353 * into the hold slot, and the free buffer into the store slot.
354 * Zero the length of the new store buffer.
356 #define ROTATE_BUFFERS(d) \
357 (d)->bd_hbuf = (d)->bd_sbuf; \
358 (d)->bd_hlen = (d)->bd_slen; \
359 (d)->bd_sbuf = (d)->bd_fbuf; \
363 * bpfread - read next chunk of packets from buffers
366 bpfread(struct dev_read_args *ap)
368 cdev_t dev = ap->a_head.a_dev;
369 struct bpf_d *d = dev->si_drv1;
374 * Restrict application to use a buffer the same size as
377 if (ap->a_uio->uio_resid != d->bd_bufsize)
381 if (d->bd_state == BPF_WAITING)
382 callout_stop(&d->bd_callout);
383 timed_out = (d->bd_state == BPF_TIMED_OUT);
384 d->bd_state = BPF_IDLE;
386 * If the hold buffer is empty, then do a timed sleep, which
387 * ends when the timeout expires or when enough packets
388 * have arrived to fill the store buffer.
390 while (d->bd_hbuf == NULL) {
391 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
393 * A packet(s) either arrived since the previous
394 * read or arrived while we were asleep.
395 * Rotate the buffers and return what's here.
402 * No data is available, check to see if the bpf device
403 * is still pointed at a real interface. If not, return
404 * ENXIO so that the userland process knows to rebind
405 * it before using it again.
407 if (d->bd_bif == NULL) {
412 if (ap->a_ioflag & IO_NDELAY) {
416 error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
417 if (error == EINTR || error == ERESTART) {
421 if (error == EWOULDBLOCK) {
423 * On a timeout, return what's in the buffer,
424 * which may be nothing. If there is something
425 * in the store buffer, we can rotate the buffers.
429 * We filled up the buffer in between
430 * getting the timeout and arriving
431 * here, so we don't need to rotate.
435 if (d->bd_slen == 0) {
444 * At this point, we know we have something in the hold slot.
449 * Move data from hold buffer into user space.
450 * We know the entire buffer is transferred since
451 * we checked above that the read buffer is bpf_bufsize bytes.
453 error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
456 d->bd_fbuf = d->bd_hbuf;
466 * If there are processes sleeping on this descriptor, wake them up.
469 bpf_wakeup(struct bpf_d *d)
471 if (d->bd_state == BPF_WAITING) {
472 callout_stop(&d->bd_callout);
473 d->bd_state = BPF_IDLE;
476 if (d->bd_async && d->bd_sig && d->bd_sigio)
477 pgsigio(d->bd_sigio, d->bd_sig, 0);
480 selwakeup(&d->bd_sel);
483 d->bd_sel.si_pid = 0;
487 bpf_timed_out(void *arg)
489 struct bpf_d *d = (struct bpf_d *)arg;
492 if (d->bd_state == BPF_WAITING) {
493 d->bd_state = BPF_TIMED_OUT;
501 bpfwrite(struct dev_write_args *ap)
503 cdev_t dev = ap->a_head.a_dev;
504 struct bpf_d *d = dev->si_drv1;
508 static struct sockaddr dst;
511 if (d->bd_bif == NULL)
514 ifp = d->bd_bif->bif_ifp;
516 if (ap->a_uio->uio_resid == 0)
519 error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
520 &dst, &datlen, d->bd_wfilter);
524 if (datlen > ifp->if_mtu) {
530 dst.sa_family = pseudo_AF_HDRCMPLT;
533 lwkt_serialize_enter(ifp->if_serializer);
534 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)NULL);
535 lwkt_serialize_exit(ifp->if_serializer);
538 * The driver frees the mbuf.
544 * Reset a descriptor by flushing its packet buffer and clearing the
545 * receive and drop counts. Should be called at splimp.
548 bpf_resetd(struct bpf_d *d)
551 /* Free the hold buffer. */
552 d->bd_fbuf = d->bd_hbuf;
562 * FIONREAD Check for read packet available.
563 * SIOCGIFADDR Get interface address - convenient hook to driver.
564 * BIOCGBLEN Get buffer len [for read()].
565 * BIOCSETF Set ethernet read filter.
566 * BIOCSETWF Set ethernet write filter.
567 * BIOCFLUSH Flush read packet buffer.
568 * BIOCPROMISC Put interface into promiscuous mode.
569 * BIOCGDLT Get link layer type.
570 * BIOCGETIF Get interface name.
571 * BIOCSETIF Set interface.
572 * BIOCSRTIMEOUT Set read timeout.
573 * BIOCGRTIMEOUT Get read timeout.
574 * BIOCGSTATS Get packet stats.
575 * BIOCIMMEDIATE Set immediate mode.
576 * BIOCVERSION Get filter language version.
577 * BIOCGHDRCMPLT Get "header already complete" flag
578 * BIOCSHDRCMPLT Set "header already complete" flag
579 * BIOCGSEESENT Get "see packets sent" flag
580 * BIOCSSEESENT Set "see packets sent" flag
581 * BIOCLOCK Set "locked" flag
585 bpfioctl(struct dev_ioctl_args *ap)
587 cdev_t dev = ap->a_head.a_dev;
588 struct bpf_d *d = dev->si_drv1;
592 if (d->bd_state == BPF_WAITING)
593 callout_stop(&d->bd_callout);
594 d->bd_state = BPF_IDLE;
597 if (d->bd_locked == 1) {
625 * Check for read packet available.
637 *(int *)ap->a_data = n;
645 if (d->bd_bif == NULL) {
648 ifp = d->bd_bif->bif_ifp;
649 lwkt_serialize_enter(ifp->if_serializer);
650 error = ifp->if_ioctl(ifp, ap->a_cmd,
651 ap->a_data, ap->a_cred);
652 lwkt_serialize_exit(ifp->if_serializer);
658 * Get buffer len [for read()].
661 *(u_int *)ap->a_data = d->bd_bufsize;
668 if (d->bd_bif != NULL) {
671 u_int size = *(u_int *)ap->a_data;
673 if (size > bpf_maxbufsize)
674 *(u_int *)ap->a_data = size = bpf_maxbufsize;
675 else if (size < BPF_MINBUFSIZE)
676 *(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
677 d->bd_bufsize = size;
682 * Set link layer read filter.
686 error = bpf_setf(d, (struct bpf_program *)ap->a_data,
691 * Flush read packet buffer.
700 * Put interface into promiscuous mode.
703 if (d->bd_bif == NULL) {
705 * No interface attached yet.
711 if (d->bd_promisc == 0) {
712 error = ifpromisc(d->bd_bif->bif_ifp, 1);
720 * Get device parameters.
723 if (d->bd_bif == NULL)
726 *(u_int *)ap->a_data = d->bd_bif->bif_dlt;
730 * Get a list of supported data link types.
733 if (d->bd_bif == NULL) {
736 error = bpf_getdltlist(d,
737 (struct bpf_dltlist *)ap->a_data);
742 * Set data link type.
745 if (d->bd_bif == NULL)
748 error = bpf_setdlt(d, *(u_int *)ap->a_data);
752 * Get interface name.
755 if (d->bd_bif == NULL) {
758 struct ifnet *const ifp = d->bd_bif->bif_ifp;
759 struct ifreq *const ifr = (struct ifreq *)ap->a_data;
761 strlcpy(ifr->ifr_name, ifp->if_xname,
762 sizeof ifr->ifr_name);
770 error = bpf_setif(d, (struct ifreq *)ap->a_data);
778 struct timeval *tv = (struct timeval *)ap->a_data;
781 * Subtract 1 tick from tvtohz() since this isn't
784 if ((error = itimerfix(tv)) == 0)
785 d->bd_rtout = tvtohz_low(tv);
794 struct timeval *tv = (struct timeval *)ap->a_data;
796 tv->tv_sec = d->bd_rtout / hz;
797 tv->tv_usec = (d->bd_rtout % hz) * tick;
806 struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
808 bs->bs_recv = d->bd_rcount;
809 bs->bs_drop = d->bd_dcount;
814 * Set immediate mode.
817 d->bd_immediate = *(u_int *)ap->a_data;
822 struct bpf_version *bv = (struct bpf_version *)ap->a_data;
824 bv->bv_major = BPF_MAJOR_VERSION;
825 bv->bv_minor = BPF_MINOR_VERSION;
830 * Get "header already complete" flag
833 *(u_int *)ap->a_data = d->bd_hdrcmplt;
837 * Set "header already complete" flag
840 d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
844 * Get "see sent packets" flag
847 *(u_int *)ap->a_data = d->bd_seesent;
851 * Set "see sent packets" flag
854 d->bd_seesent = *(u_int *)ap->a_data;
857 case FIOASYNC: /* Send signal on receive packets */
858 d->bd_async = *(int *)ap->a_data;
862 error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
866 *(int *)ap->a_data = fgetown(d->bd_sigio);
869 /* This is deprecated, FIOSETOWN should be used instead. */
871 error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
874 /* This is deprecated, FIOGETOWN should be used instead. */
876 *(int *)ap->a_data = -fgetown(d->bd_sigio);
879 case BIOCSRSIG: /* Set receive signal */
883 sig = *(u_int *)ap->a_data;
892 *(u_int *)ap->a_data = d->bd_sig;
902 * Set d's packet filter program to fp. If this file already has a filter,
903 * free it and replace it. Returns EINVAL for bogus requests.
906 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
908 struct bpf_insn *fcode, *old;
909 u_int wfilter, flen, size;
911 if (cmd == BIOCSETWF) {
918 if (fp->bf_insns == NULL) {
923 d->bd_wfilter = NULL;
925 d->bd_rfilter = NULL;
933 if (flen > BPF_MAXINSNS)
936 size = flen * sizeof *fp->bf_insns;
937 fcode = (struct bpf_insn *)kmalloc(size, M_BPF, M_WAITOK);
938 if (copyin(fp->bf_insns, fcode, size) == 0 &&
939 bpf_validate(fcode, (int)flen)) {
942 d->bd_wfilter = fcode;
944 d->bd_rfilter = fcode;
957 * Detach a file from its current interface (if attached at all) and attach
958 * to the interface indicated by the name stored in ifr.
959 * Return an errno or 0.
962 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
966 struct ifnet *theywant;
968 theywant = ifunit(ifr->ifr_name);
969 if (theywant == NULL)
973 * Look through attached interfaces for the named one.
975 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
976 struct ifnet *ifp = bp->bif_ifp;
978 if (ifp == NULL || ifp != theywant)
980 /* skip additional entry */
981 if (bp->bif_driverp != &ifp->if_bpf)
984 * We found the requested interface.
985 * If it's not up, return an error.
986 * Allocate the packet buffers if we need to.
987 * If we're already attached to requested interface,
988 * just flush the buffer.
990 if (!(ifp->if_flags & IFF_UP))
993 if (d->bd_sbuf == NULL) {
994 error = bpf_allocbufs(d);
999 if (bp != d->bd_bif) {
1000 if (d->bd_bif != NULL) {
1002 * Detach if attached to something else.
1019 * Support for select() and poll() system calls
1021 * Return true iff the specific operation will not block indefinitely.
1022 * Otherwise, return false but make a note that a selwakeup() must be done.
1025 bpfpoll(struct dev_poll_args *ap)
1027 cdev_t dev = ap->a_head.a_dev;
1032 if (d->bd_bif == NULL)
1035 revents = ap->a_events & (POLLOUT | POLLWRNORM);
1037 if (ap->a_events & (POLLIN | POLLRDNORM)) {
1039 * An imitation of the FIONREAD ioctl code.
1040 * XXX not quite. An exact imitation:
1041 * if (d->b_slen != 0 ||
1042 * (d->bd_hbuf != NULL && d->bd_hlen != 0)
1044 if (d->bd_hlen != 0 ||
1045 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1047 revents |= ap->a_events & (POLLIN | POLLRDNORM);
1049 selrecord(curthread, &d->bd_sel);
1050 /* Start the read timeout if necessary. */
1051 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1052 callout_reset(&d->bd_callout, d->bd_rtout,
1054 d->bd_state = BPF_WAITING;
1059 ap->a_events = revents;
1064 * Process the packet pkt of length pktlen. The packet is parsed
1065 * by each listener's filter, and if accepted, stashed into the
1066 * corresponding buffer.
1069 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1077 * Note that the ipl does not have to be raised at this point.
1078 * The only problem that could arise here is that if two different
1079 * interfaces shared any data. This is not the case.
1081 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1083 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
1089 catchpacket(d, pkt, pktlen, slen, ovbcopy, &tv);
1095 * Copy data from an mbuf chain into a buffer. This code is derived
1096 * from m_copydata in sys/uipc_mbuf.c.
1099 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1101 const struct mbuf *m;
1110 count = min(m->m_len, len);
1111 bcopy(mtod(m, void *), dst, count);
1119 * Process the packet in the mbuf chain m. The packet is parsed by each
1120 * listener's filter, and if accepted, stashed into the corresponding
1124 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1131 /* Don't compute pktlen, if no descriptor is attached. */
1132 if (SLIST_EMPTY(&bp->bif_dlist))
1135 pktlen = m_lengthm(m, NULL);
1137 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1138 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1141 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
1147 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy,
1154 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1158 KKASSERT(family != AF_UNSPEC);
1160 family4 = (u_int)family;
1161 bpf_ptap(bp, m, &family4, sizeof(family4));
1165 * Process the packet in the mbuf chain m with the header in m prepended.
1166 * The packet is parsed by each listener's filter, and if accepted,
1167 * stashed into the corresponding buffer.
1170 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1175 * Craft on-stack mbuf suitable for passing to bpf_mtap.
1176 * Note that we cut corners here; we only setup what's
1177 * absolutely needed--this mbuf should never go anywhere else.
1180 mb.m_data = __DECONST(void *, data); /* LINTED */
1182 mb.m_pkthdr.rcvif = m->m_pkthdr.rcvif;
1188 * Move the packet data from interface memory (pkt) into the
1189 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1190 * otherwise 0. "copy" is the routine called to do the actual data
1191 * transfer. bcopy is passed in to copy contiguous chunks, while
1192 * bpf_mcopy is passed in to copy mbuf chains. In the latter case,
1193 * pkt is really an mbuf.
1196 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1197 void (*cpfn)(const void *, void *, size_t),
1198 const struct timeval *tv)
1202 int hdrlen = d->bd_bif->bif_hdrlen;
1204 * Figure out how many bytes to move. If the packet is
1205 * greater or equal to the snapshot length, transfer that
1206 * much. Otherwise, transfer the whole packet (unless
1207 * we hit the buffer size limit).
1209 totlen = hdrlen + min(snaplen, pktlen);
1210 if (totlen > d->bd_bufsize)
1211 totlen = d->bd_bufsize;
1214 * Round up the end of the previous packet to the next longword.
1216 curlen = BPF_WORDALIGN(d->bd_slen);
1217 if (curlen + totlen > d->bd_bufsize) {
1219 * This packet will overflow the storage buffer.
1220 * Rotate the buffers if we can, then wakeup any
1223 if (d->bd_fbuf == NULL) {
1225 * We haven't completed the previous read yet,
1226 * so drop the packet.
1234 } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) {
1236 * Immediate mode is set, or the read timeout has
1237 * already expired during a select call. A packet
1238 * arrived, so the reader should be woken up.
1244 * Append the bpf header.
1246 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1247 hp->bh_tstamp = *tv;
1248 hp->bh_datalen = pktlen;
1249 hp->bh_hdrlen = hdrlen;
1251 * Copy the packet data into the store buffer and update its length.
1253 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1254 d->bd_slen = curlen + totlen;
1258 * Initialize all nonzero fields of a descriptor.
1261 bpf_allocbufs(struct bpf_d *d)
1263 d->bd_fbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1264 d->bd_sbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1271 * Free buffers and packet filter program currently in use by a descriptor.
1275 bpf_freed(struct bpf_d *d)
1278 * We don't need to lock out interrupts since this descriptor has
1279 * been detached from its interface and it yet hasn't been marked
1282 if (d->bd_sbuf != NULL) {
1283 kfree(d->bd_sbuf, M_BPF);
1284 if (d->bd_hbuf != NULL)
1285 kfree(d->bd_hbuf, M_BPF);
1286 if (d->bd_fbuf != NULL)
1287 kfree(d->bd_fbuf, M_BPF);
1290 kfree(d->bd_rfilter, M_BPF);
1292 kfree(d->bd_wfilter, M_BPF);
1296 * Attach an interface to bpf. ifp is a pointer to the structure
1297 * defining the interface to be attached, dlt is the link layer type,
1298 * and hdrlen is the fixed size of the link header (variable length
1299 * headers are not yet supported).
1302 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1304 bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1308 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1312 bp = kmalloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1314 SLIST_INIT(&bp->bif_dlist);
1317 bp->bif_driverp = driverp;
1318 *bp->bif_driverp = NULL;
1320 bp->bif_next = bpf_iflist;
1324 * Compute the length of the bpf header. This is not necessarily
1325 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1326 * that the network layer header begins on a longword boundary (for
1327 * performance reasons and to alleviate alignment restrictions).
1329 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1332 if_printf(ifp, "bpf attached\n");
1336 * Detach bpf from an interface. This involves detaching each descriptor
1337 * associated with the interface, and leaving bd_bif NULL. Notify each
1338 * descriptor as it's detached so that any sleepers wake up and get
1342 bpfdetach(struct ifnet *ifp)
1344 struct bpf_if *bp, *bp_prev;
1349 /* Locate BPF interface information */
1351 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1352 if (ifp == bp->bif_ifp)
1357 /* Interface wasn't attached */
1358 if (bp->bif_ifp == NULL) {
1360 kprintf("bpfdetach: %s was not attached\n", ifp->if_xname);
1364 while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1369 if (bp_prev != NULL)
1370 bp_prev->bif_next = bp->bif_next;
1372 bpf_iflist = bp->bif_next;
1380 * Get a list of available data link type of the interface.
1383 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1389 ifp = d->bd_bif->bif_ifp;
1392 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1393 if (bp->bif_ifp != ifp)
1395 if (bfl->bfl_list != NULL) {
1396 if (n >= bfl->bfl_len) {
1399 error = copyout(&bp->bif_dlt,
1400 bfl->bfl_list + n, sizeof(u_int));
1409 * Set the data link type of a BPF instance.
1412 bpf_setdlt(struct bpf_d *d, u_int dlt)
1414 int error, opromisc;
1418 if (d->bd_bif->bif_dlt == dlt)
1420 ifp = d->bd_bif->bif_ifp;
1421 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1422 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1426 opromisc = d->bd_promisc;
1432 error = ifpromisc(bp->bif_ifp, 1);
1434 if_printf(bp->bif_ifp,
1435 "bpf_setdlt: ifpromisc failed (%d)\n",
1443 return(bp == NULL ? EINVAL : 0);
1447 bpf_drvinit(void *unused)
1449 dev_ops_add(&bpf_ops, 0, 0);
1452 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1456 * NOP stubs to allow bpf-using drivers to load and function.
1458 * A 'better' implementation would allow the core bpf functionality
1459 * to be loaded at runtime.
1463 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1468 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1473 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1478 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1483 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1488 bpfdetach(struct ifnet *ifp)
1493 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1495 return -1; /* "no filter" behaviour */