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 1.31 2006/07/28 02:17:40 dillon 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 static 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_freed(struct bpf_d *);
99 static void bpf_mcopy(const void *, void *, size_t);
100 static int bpf_movein(struct uio *, int, struct mbuf **,
101 struct sockaddr *, int *);
102 static int bpf_setif(struct bpf_d *, struct ifreq *);
103 static void bpf_timed_out(void *);
104 static void bpf_wakeup(struct bpf_d *);
105 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
106 void (*)(const void *, void *, size_t));
107 static void reset_d(struct bpf_d *);
108 static int bpf_setf(struct bpf_d *, struct bpf_program *);
109 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
110 static int bpf_setdlt(struct bpf_d *, u_int);
111 static void bpf_drvinit(void *unused);
113 static d_open_t bpfopen;
114 static d_close_t bpfclose;
115 static d_read_t bpfread;
116 static d_write_t bpfwrite;
117 static d_ioctl_t bpfioctl;
118 static d_poll_t bpfpoll;
120 #define CDEV_MAJOR 23
121 static struct dev_ops bpf_ops = {
122 { "bpf", CDEV_MAJOR, 0 },
133 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp,
134 struct sockaddr *sockp, int *datlen)
142 * Build a sockaddr based on the data link layer type.
143 * We do this at this level because the ethernet header
144 * is copied directly into the data field of the sockaddr.
145 * In the case of SLIP, there is no header and the packet
146 * is forwarded as is.
147 * Also, we are careful to leave room at the front of the mbuf
148 * for the link level header.
153 sockp->sa_family = AF_INET;
158 sockp->sa_family = AF_UNSPEC;
159 /* XXX Would MAXLINKHDR be better? */
160 hlen = sizeof(struct ether_header);
164 sockp->sa_family = AF_IMPLINK;
170 sockp->sa_family = AF_UNSPEC;
174 case DLT_ATM_RFC1483:
176 * en atm driver requires 4-byte atm pseudo header.
177 * though it isn't standard, vpi:vci needs to be
180 sockp->sa_family = AF_UNSPEC;
181 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
185 sockp->sa_family = AF_UNSPEC;
186 hlen = 4; /* This should match PPP_HDRLEN */
193 len = uio->uio_resid;
194 *datlen = len - hlen;
195 if ((unsigned)len > MCLBYTES)
198 MGETHDR(m, MB_WAIT, MT_DATA);
203 if (!(m->m_flags & M_EXT)) {
208 m->m_pkthdr.len = m->m_len = len;
209 m->m_pkthdr.rcvif = NULL;
212 * Make room for link header.
215 m->m_pkthdr.len -= hlen;
217 m->m_data += hlen; /* XXX */
218 error = uiomove(sockp->sa_data, hlen, uio);
222 error = uiomove(mtod(m, caddr_t), len - hlen, uio);
231 * Attach file to the bpf interface, i.e. make d listen on bp.
232 * Must be called at splimp.
235 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
238 * Point d at bp, and add d to the interface's list of listeners.
239 * Finally, point the driver's bpf cookie at the interface so
240 * it will divert packets to bpf.
243 SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
244 *bp->bif_driverp = bp;
248 * Detach a file from its interface.
251 bpf_detachd(struct bpf_d *d)
260 /* Remove d from the interface's descriptor list. */
261 SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
263 if (SLIST_EMPTY(&bp->bif_dlist)) {
265 * Let the driver know that there are no more listeners.
267 *bp->bif_driverp = NULL;
271 * Check if this descriptor had requested promiscuous mode.
272 * If so, turn it off.
276 error = ifpromisc(ifp, 0);
277 if (error != 0 && error != ENXIO) {
279 * ENXIO can happen if a pccard is unplugged,
280 * Something is really wrong if we were able to put
281 * the driver into promiscuous mode, but can't
284 if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
291 * Open ethernet device. Returns ENXIO for illegal minor device number,
292 * EBUSY if file is open by another process.
296 bpfopen(struct dev_open_args *ap)
298 dev_t dev = ap->a_head.a_dev;
301 if (ap->a_cred->cr_prison)
306 * Each minor can be opened by only one process. If the requested
307 * minor is in use, return EBUSY.
311 make_dev(&bpf_ops, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
312 MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
314 d->bd_bufsize = bpf_bufsize;
317 callout_init(&d->bd_callout);
322 * Close the descriptor by detaching it from its interface,
323 * deallocating its buffers, and marking it free.
327 bpfclose(struct dev_close_args *ap)
329 dev_t dev = ap->a_head.a_dev;
330 struct bpf_d *d = dev->si_drv1;
332 funsetown(d->bd_sigio);
334 if (d->bd_state == BPF_WAITING)
335 callout_stop(&d->bd_callout);
336 d->bd_state = BPF_IDLE;
337 if (d->bd_bif != NULL)
348 * Rotate the packet buffers in descriptor d. Move the store buffer
349 * into the hold slot, and the free buffer into the store slot.
350 * Zero the length of the new store buffer.
352 #define ROTATE_BUFFERS(d) \
353 (d)->bd_hbuf = (d)->bd_sbuf; \
354 (d)->bd_hlen = (d)->bd_slen; \
355 (d)->bd_sbuf = (d)->bd_fbuf; \
359 * bpfread - read next chunk of packets from buffers
362 bpfread(struct dev_read_args *ap)
364 dev_t dev = ap->a_head.a_dev;
365 struct bpf_d *d = dev->si_drv1;
370 * Restrict application to use a buffer the same size as
373 if (ap->a_uio->uio_resid != d->bd_bufsize)
377 if (d->bd_state == BPF_WAITING)
378 callout_stop(&d->bd_callout);
379 timed_out = (d->bd_state == BPF_TIMED_OUT);
380 d->bd_state = BPF_IDLE;
382 * If the hold buffer is empty, then do a timed sleep, which
383 * ends when the timeout expires or when enough packets
384 * have arrived to fill the store buffer.
386 while (d->bd_hbuf == NULL) {
387 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
389 * A packet(s) either arrived since the previous
390 * read or arrived while we were asleep.
391 * Rotate the buffers and return what's here.
398 * No data is available, check to see if the bpf device
399 * is still pointed at a real interface. If not, return
400 * ENXIO so that the userland process knows to rebind
401 * it before using it again.
403 if (d->bd_bif == NULL) {
408 if (ap->a_ioflag & IO_NDELAY) {
412 error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
413 if (error == EINTR || error == ERESTART) {
417 if (error == EWOULDBLOCK) {
419 * On a timeout, return what's in the buffer,
420 * which may be nothing. If there is something
421 * in the store buffer, we can rotate the buffers.
425 * We filled up the buffer in between
426 * getting the timeout and arriving
427 * here, so we don't need to rotate.
431 if (d->bd_slen == 0) {
440 * At this point, we know we have something in the hold slot.
445 * Move data from hold buffer into user space.
446 * We know the entire buffer is transferred since
447 * we checked above that the read buffer is bpf_bufsize bytes.
449 error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
452 d->bd_fbuf = d->bd_hbuf;
462 * If there are processes sleeping on this descriptor, wake them up.
465 bpf_wakeup(struct bpf_d *d)
467 if (d->bd_state == BPF_WAITING) {
468 callout_stop(&d->bd_callout);
469 d->bd_state = BPF_IDLE;
472 if (d->bd_async && d->bd_sig && d->bd_sigio)
473 pgsigio(d->bd_sigio, d->bd_sig, 0);
476 selwakeup(&d->bd_sel);
479 d->bd_sel.si_pid = 0;
483 bpf_timed_out(void *arg)
485 struct bpf_d *d = (struct bpf_d *)arg;
488 if (d->bd_state == BPF_WAITING) {
489 d->bd_state = BPF_TIMED_OUT;
497 bpfwrite(struct dev_write_args *ap)
499 dev_t dev = ap->a_head.a_dev;
500 struct bpf_d *d = dev->si_drv1;
504 static struct sockaddr dst;
507 if (d->bd_bif == NULL)
510 ifp = d->bd_bif->bif_ifp;
512 if (ap->a_uio->uio_resid == 0)
515 error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
520 if (datlen > ifp->if_mtu) {
526 dst.sa_family = pseudo_AF_HDRCMPLT;
529 lwkt_serialize_enter(ifp->if_serializer);
530 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)NULL);
531 lwkt_serialize_exit(ifp->if_serializer);
534 * The driver frees the mbuf.
540 * Reset a descriptor by flushing its packet buffer and clearing the
541 * receive and drop counts. Should be called at splimp.
544 reset_d(struct bpf_d *d)
547 /* Free the hold buffer. */
548 d->bd_fbuf = d->bd_hbuf;
558 * FIONREAD Check for read packet available.
559 * SIOCGIFADDR Get interface address - convenient hook to driver.
560 * BIOCGBLEN Get buffer len [for read()].
561 * BIOCSETF Set ethernet read filter.
562 * BIOCFLUSH Flush read packet buffer.
563 * BIOCPROMISC Put interface into promiscuous mode.
564 * BIOCGDLT Get link layer type.
565 * BIOCGETIF Get interface name.
566 * BIOCSETIF Set interface.
567 * BIOCSRTIMEOUT Set read timeout.
568 * BIOCGRTIMEOUT Get read timeout.
569 * BIOCGSTATS Get packet stats.
570 * BIOCIMMEDIATE Set immediate mode.
571 * BIOCVERSION Get filter language version.
572 * BIOCGHDRCMPLT Get "header already complete" flag
573 * BIOCSHDRCMPLT Set "header already complete" flag
574 * BIOCGSEESENT Get "see packets sent" flag
575 * BIOCSSEESENT Set "see packets sent" flag
579 bpfioctl(struct dev_ioctl_args *ap)
581 dev_t dev = ap->a_head.a_dev;
582 struct bpf_d *d = dev->si_drv1;
586 if (d->bd_state == BPF_WAITING)
587 callout_stop(&d->bd_callout);
588 d->bd_state = BPF_IDLE;
597 * Check for read packet available.
609 *(int *)ap->a_data = n;
617 if (d->bd_bif == NULL)
620 ifp = d->bd_bif->bif_ifp;
621 lwkt_serialize_enter(ifp->if_serializer);
622 error = ifp->if_ioctl(ifp, ap->a_cmd,
623 ap->a_data, ap->a_cred);
624 lwkt_serialize_exit(ifp->if_serializer);
630 * Get buffer len [for read()].
633 *(u_int *)ap->a_data = d->bd_bufsize;
643 u_int size = *(u_int *)ap->a_data;
645 if (size > bpf_maxbufsize)
646 *(u_int *)ap->a_data = size = bpf_maxbufsize;
647 else if (size < BPF_MINBUFSIZE)
648 *(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
649 d->bd_bufsize = size;
654 * Set link layer read filter.
657 error = bpf_setf(d, (struct bpf_program *)ap->a_data);
661 * Flush read packet buffer.
670 * Put interface into promiscuous mode.
673 if (d->bd_bif == NULL) {
675 * No interface attached yet.
681 if (d->bd_promisc == 0) {
682 error = ifpromisc(d->bd_bif->bif_ifp, 1);
690 * Get device parameters.
693 if (d->bd_bif == NULL)
696 *(u_int *)ap->a_data = d->bd_bif->bif_dlt;
700 * Get a list of supported data link types.
703 if (d->bd_bif == NULL)
706 error = bpf_getdltlist(d, (struct bpf_dltlist *)ap->a_data);
710 * Set data link type.
713 if (d->bd_bif == NULL)
716 error = bpf_setdlt(d, *(u_int *)ap->a_data);
720 * Get interface name.
723 if (d->bd_bif == NULL) {
726 struct ifnet *const ifp = d->bd_bif->bif_ifp;
727 struct ifreq *const ifr = (struct ifreq *)ap->a_data;
729 strlcpy(ifr->ifr_name, ifp->if_xname,
730 sizeof ifr->ifr_name);
738 error = bpf_setif(d, (struct ifreq *)ap->a_data);
746 struct timeval *tv = (struct timeval *)ap->a_data;
749 * Subtract 1 tick from tvtohz() since this isn't
752 if ((error = itimerfix(tv)) == 0)
753 d->bd_rtout = tvtohz_low(tv);
762 struct timeval *tv = (struct timeval *)ap->a_data;
764 tv->tv_sec = d->bd_rtout / hz;
765 tv->tv_usec = (d->bd_rtout % hz) * tick;
774 struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
776 bs->bs_recv = d->bd_rcount;
777 bs->bs_drop = d->bd_dcount;
782 * Set immediate mode.
785 d->bd_immediate = *(u_int *)ap->a_data;
790 struct bpf_version *bv = (struct bpf_version *)ap->a_data;
792 bv->bv_major = BPF_MAJOR_VERSION;
793 bv->bv_minor = BPF_MINOR_VERSION;
798 * Get "header already complete" flag
801 *(u_int *)ap->a_data = d->bd_hdrcmplt;
805 * Set "header already complete" flag
808 d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
812 * Get "see sent packets" flag
815 *(u_int *)ap->a_data = d->bd_seesent;
819 * Set "see sent packets" flag
822 d->bd_seesent = *(u_int *)ap->a_data;
825 case FIOASYNC: /* Send signal on receive packets */
826 d->bd_async = *(int *)ap->a_data;
830 error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
834 *(int *)ap->a_data = fgetown(d->bd_sigio);
837 /* This is deprecated, FIOSETOWN should be used instead. */
839 error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
842 /* This is deprecated, FIOGETOWN should be used instead. */
844 *(int *)ap->a_data = -fgetown(d->bd_sigio);
847 case BIOCSRSIG: /* Set receive signal */
851 sig = *(u_int *)ap->a_data;
860 *(u_int *)ap->a_data = d->bd_sig;
867 * Set d's packet filter program to fp. If this file already has a filter,
868 * free it and replace it. Returns EINVAL for bogus requests.
871 bpf_setf(struct bpf_d *d, struct bpf_program *fp)
873 struct bpf_insn *fcode, *old;
877 if (fp->bf_insns == NULL) {
889 if (flen > BPF_MAXINSNS)
892 size = flen * sizeof *fp->bf_insns;
893 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK);
894 if (copyin(fp->bf_insns, fcode, size) == 0 &&
895 bpf_validate(fcode, (int)flen)) {
897 d->bd_filter = fcode;
910 * Detach a file from its current interface (if attached at all) and attach
911 * to the interface indicated by the name stored in ifr.
912 * Return an errno or 0.
915 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
919 struct ifnet *theywant;
921 theywant = ifunit(ifr->ifr_name);
922 if (theywant == NULL)
926 * Look through attached interfaces for the named one.
928 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
929 struct ifnet *ifp = bp->bif_ifp;
931 if (ifp == NULL || ifp != theywant)
933 /* skip additional entry */
934 if (bp->bif_driverp != &ifp->if_bpf)
937 * We found the requested interface.
938 * If it's not up, return an error.
939 * Allocate the packet buffers if we need to.
940 * If we're already attached to requested interface,
941 * just flush the buffer.
943 if (!(ifp->if_flags & IFF_UP))
946 if (d->bd_sbuf == NULL) {
947 error = bpf_allocbufs(d);
952 if (bp != d->bd_bif) {
953 if (d->bd_bif != NULL) {
955 * Detach if attached to something else.
972 * Support for select() and poll() system calls
974 * Return true iff the specific operation will not block indefinitely.
975 * Otherwise, return false but make a note that a selwakeup() must be done.
978 bpfpoll(struct dev_poll_args *ap)
980 dev_t dev = ap->a_head.a_dev;
985 if (d->bd_bif == NULL)
988 revents = ap->a_events & (POLLOUT | POLLWRNORM);
990 if (ap->a_events & (POLLIN | POLLRDNORM)) {
992 * An imitation of the FIONREAD ioctl code.
993 * XXX not quite. An exact imitation:
994 * if (d->b_slen != 0 ||
995 * (d->bd_hbuf != NULL && d->bd_hlen != 0)
997 if (d->bd_hlen != 0 ||
998 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1000 revents |= ap->a_events & (POLLIN | POLLRDNORM);
1002 selrecord(curthread, &d->bd_sel);
1003 /* Start the read timeout if necessary. */
1004 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1005 callout_reset(&d->bd_callout, d->bd_rtout,
1007 d->bd_state = BPF_WAITING;
1012 ap->a_events = revents;
1017 * Process the packet pkt of length pktlen. The packet is parsed
1018 * by each listener's filter, and if accepted, stashed into the
1019 * corresponding buffer.
1022 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1028 * Note that the ipl does not have to be raised at this point.
1029 * The only problem that could arise here is that if two different
1030 * interfaces shared any data. This is not the case.
1032 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1034 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
1036 catchpacket(d, pkt, pktlen, slen, ovbcopy);
1041 * Copy data from an mbuf chain into a buffer. This code is derived
1042 * from m_copydata in sys/uipc_mbuf.c.
1045 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1047 const struct mbuf *m;
1056 count = min(m->m_len, len);
1057 bcopy(mtod(m, void *), dst, count);
1065 * Process the packet in the mbuf chain m. The packet is parsed by each
1066 * listener's filter, and if accepted, stashed into the corresponding
1070 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1076 /* Don't compute pktlen, if no descriptor is attached. */
1077 if (SLIST_EMPTY(&bp->bif_dlist))
1081 for (m0 = m; m0 != NULL; m0 = m0->m_next)
1082 pktlen += m0->m_len;
1084 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1085 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1088 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0);
1090 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy);
1095 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1099 KKASSERT(family != AF_UNSPEC);
1101 family4 = (u_int)family;
1102 bpf_ptap(bp, m, &family4, sizeof(family4));
1106 * Process the packet in the mbuf chain m with the header in m prepended.
1107 * The packet is parsed by each listener's filter, and if accepted,
1108 * stashed into the corresponding buffer.
1111 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1116 * Craft on-stack mbuf suitable for passing to bpf_mtap.
1117 * Note that we cut corners here; we only setup what's
1118 * absolutely needed--this mbuf should never go anywhere else.
1121 mb.m_data = __DECONST(void *, data); /* LINTED */
1128 * Move the packet data from interface memory (pkt) into the
1129 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1130 * otherwise 0. "copy" is the routine called to do the actual data
1131 * transfer. bcopy is passed in to copy contiguous chunks, while
1132 * bpf_mcopy is passed in to copy mbuf chains. In the latter case,
1133 * pkt is really an mbuf.
1136 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1137 void (*cpfn)(const void *, void *, size_t))
1141 int hdrlen = d->bd_bif->bif_hdrlen;
1143 * Figure out how many bytes to move. If the packet is
1144 * greater or equal to the snapshot length, transfer that
1145 * much. Otherwise, transfer the whole packet (unless
1146 * we hit the buffer size limit).
1148 totlen = hdrlen + min(snaplen, pktlen);
1149 if (totlen > d->bd_bufsize)
1150 totlen = d->bd_bufsize;
1153 * Round up the end of the previous packet to the next longword.
1155 curlen = BPF_WORDALIGN(d->bd_slen);
1156 if (curlen + totlen > d->bd_bufsize) {
1158 * This packet will overflow the storage buffer.
1159 * Rotate the buffers if we can, then wakeup any
1162 if (d->bd_fbuf == NULL) {
1164 * We haven't completed the previous read yet,
1165 * so drop the packet.
1174 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
1176 * Immediate mode is set, or the read timeout has
1177 * already expired during a select call. A packet
1178 * arrived, so the reader should be woken up.
1183 * Append the bpf header.
1185 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1186 microtime(&hp->bh_tstamp);
1187 hp->bh_datalen = pktlen;
1188 hp->bh_hdrlen = hdrlen;
1190 * Copy the packet data into the store buffer and update its length.
1192 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1193 d->bd_slen = curlen + totlen;
1197 * Initialize all nonzero fields of a descriptor.
1200 bpf_allocbufs(struct bpf_d *d)
1202 d->bd_fbuf = malloc(d->bd_bufsize, M_BPF, M_WAITOK);
1203 if (d->bd_fbuf == NULL)
1206 d->bd_sbuf = malloc(d->bd_bufsize, M_BPF, M_WAITOK);
1207 if (d->bd_sbuf == NULL) {
1208 free(d->bd_fbuf, M_BPF);
1217 * Free buffers currently in use by a descriptor.
1221 bpf_freed(struct bpf_d *d)
1224 * We don't need to lock out interrupts since this descriptor has
1225 * been detached from its interface and it yet hasn't been marked
1228 if (d->bd_sbuf != NULL) {
1229 free(d->bd_sbuf, M_BPF);
1230 if (d->bd_hbuf != NULL)
1231 free(d->bd_hbuf, M_BPF);
1232 if (d->bd_fbuf != NULL)
1233 free(d->bd_fbuf, M_BPF);
1236 free(d->bd_filter, M_BPF);
1240 * Attach an interface to bpf. ifp is a pointer to the structure
1241 * defining the interface to be attached, dlt is the link layer type,
1242 * and hdrlen is the fixed size of the link header (variable length
1243 * headers are not yet supported).
1246 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1248 bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1252 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1256 bp = malloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1258 SLIST_INIT(&bp->bif_dlist);
1261 bp->bif_driverp = driverp;
1262 *bp->bif_driverp = NULL;
1264 bp->bif_next = bpf_iflist;
1268 * Compute the length of the bpf header. This is not necessarily
1269 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1270 * that the network layer header begins on a longword boundary (for
1271 * performance reasons and to alleviate alignment restrictions).
1273 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1276 if_printf(ifp, "bpf attached\n");
1280 * Detach bpf from an interface. This involves detaching each descriptor
1281 * associated with the interface, and leaving bd_bif NULL. Notify each
1282 * descriptor as it's detached so that any sleepers wake up and get
1286 bpfdetach(struct ifnet *ifp)
1288 struct bpf_if *bp, *bp_prev;
1293 /* Locate BPF interface information */
1295 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1296 if (ifp == bp->bif_ifp)
1301 /* Interface wasn't attached */
1302 if (bp->bif_ifp == NULL) {
1304 printf("bpfdetach: %s was not attached\n", ifp->if_xname);
1308 while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1313 if (bp_prev != NULL)
1314 bp_prev->bif_next = bp->bif_next;
1316 bpf_iflist = bp->bif_next;
1324 * Get a list of available data link type of the interface.
1327 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1333 ifp = d->bd_bif->bif_ifp;
1336 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
1337 if (bp->bif_ifp != ifp)
1339 if (bfl->bfl_list != NULL) {
1340 if (n >= bfl->bfl_len) {
1343 error = copyout(&bp->bif_dlt,
1344 bfl->bfl_list + n, sizeof(u_int));
1353 * Set the data link type of a BPF instance.
1356 bpf_setdlt(struct bpf_d *d, u_int dlt)
1358 int error, opromisc;
1362 if (d->bd_bif->bif_dlt == dlt)
1364 ifp = d->bd_bif->bif_ifp;
1365 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
1366 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1370 opromisc = d->bd_promisc;
1376 error = ifpromisc(bp->bif_ifp, 1);
1378 if_printf(bp->bif_ifp,
1379 "bpf_setdlt: ifpromisc failed (%d)\n",
1386 return(bp == NULL ? EINVAL : 0);
1390 bpf_drvinit(void *unused)
1392 dev_ops_add(&bpf_ops, 0, 0);
1395 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1399 * NOP stubs to allow bpf-using drivers to load and function.
1401 * A 'better' implementation would allow the core bpf functionality
1402 * to be loaded at runtime.
1406 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1411 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1416 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1421 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1426 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1431 bpfdetach(struct ifnet *ifp)
1436 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1438 return -1; /* "no filter" behaviour */