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 1.34 2006/09/10 01:26:39 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 const struct timeval *);
108 static void reset_d(struct bpf_d *);
109 static int bpf_setf(struct bpf_d *, struct bpf_program *);
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)
143 * Build a sockaddr based on the data link layer type.
144 * We do this at this level because the ethernet header
145 * is copied directly into the data field of the sockaddr.
146 * In the case of SLIP, there is no header and the packet
147 * is forwarded as is.
148 * Also, we are careful to leave room at the front of the mbuf
149 * for the link level header.
154 sockp->sa_family = AF_INET;
159 sockp->sa_family = AF_UNSPEC;
160 /* XXX Would MAXLINKHDR be better? */
161 hlen = sizeof(struct ether_header);
165 sockp->sa_family = AF_IMPLINK;
171 sockp->sa_family = AF_UNSPEC;
175 case DLT_ATM_RFC1483:
177 * en atm driver requires 4-byte atm pseudo header.
178 * though it isn't standard, vpi:vci needs to be
181 sockp->sa_family = AF_UNSPEC;
182 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
186 sockp->sa_family = AF_UNSPEC;
187 hlen = 4; /* This should match PPP_HDRLEN */
194 len = uio->uio_resid;
195 *datlen = len - hlen;
196 if ((unsigned)len > MCLBYTES)
199 MGETHDR(m, MB_WAIT, MT_DATA);
204 if (!(m->m_flags & M_EXT)) {
209 m->m_pkthdr.len = m->m_len = len;
210 m->m_pkthdr.rcvif = NULL;
213 * Make room for link header.
216 m->m_pkthdr.len -= hlen;
218 m->m_data += hlen; /* XXX */
219 error = uiomove(sockp->sa_data, hlen, uio);
223 error = uiomove(mtod(m, caddr_t), len - hlen, uio);
232 * Attach file to the bpf interface, i.e. make d listen on bp.
233 * Must be called at splimp.
236 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
239 * Point d at bp, and add d to the interface's list of listeners.
240 * Finally, point the driver's bpf cookie at the interface so
241 * it will divert packets to bpf.
244 SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
245 *bp->bif_driverp = bp;
249 * Detach a file from its interface.
252 bpf_detachd(struct bpf_d *d)
261 /* Remove d from the interface's descriptor list. */
262 SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
264 if (SLIST_EMPTY(&bp->bif_dlist)) {
266 * Let the driver know that there are no more listeners.
268 *bp->bif_driverp = NULL;
272 * Check if this descriptor had requested promiscuous mode.
273 * If so, turn it off.
277 error = ifpromisc(ifp, 0);
278 if (error != 0 && error != ENXIO) {
280 * ENXIO can happen if a pccard is unplugged,
281 * Something is really wrong if we were able to put
282 * the driver into promiscuous mode, but can't
285 if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
292 * Open ethernet device. Returns ENXIO for illegal minor device number,
293 * EBUSY if file is open by another process.
297 bpfopen(struct dev_open_args *ap)
299 cdev_t dev = ap->a_head.a_dev;
302 if (ap->a_cred->cr_prison)
307 * Each minor can be opened by only one process. If the requested
308 * minor is in use, return EBUSY.
312 make_dev(&bpf_ops, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
313 MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
315 d->bd_bufsize = bpf_bufsize;
318 callout_init(&d->bd_callout);
323 * Close the descriptor by detaching it from its interface,
324 * deallocating its buffers, and marking it free.
328 bpfclose(struct dev_close_args *ap)
330 cdev_t dev = ap->a_head.a_dev;
331 struct bpf_d *d = dev->si_drv1;
333 funsetown(d->bd_sigio);
335 if (d->bd_state == BPF_WAITING)
336 callout_stop(&d->bd_callout);
337 d->bd_state = BPF_IDLE;
338 if (d->bd_bif != NULL)
349 * Rotate the packet buffers in descriptor d. Move the store buffer
350 * into the hold slot, and the free buffer into the store slot.
351 * Zero the length of the new store buffer.
353 #define ROTATE_BUFFERS(d) \
354 (d)->bd_hbuf = (d)->bd_sbuf; \
355 (d)->bd_hlen = (d)->bd_slen; \
356 (d)->bd_sbuf = (d)->bd_fbuf; \
360 * bpfread - read next chunk of packets from buffers
363 bpfread(struct dev_read_args *ap)
365 cdev_t dev = ap->a_head.a_dev;
366 struct bpf_d *d = dev->si_drv1;
371 * Restrict application to use a buffer the same size as
374 if (ap->a_uio->uio_resid != d->bd_bufsize)
378 if (d->bd_state == BPF_WAITING)
379 callout_stop(&d->bd_callout);
380 timed_out = (d->bd_state == BPF_TIMED_OUT);
381 d->bd_state = BPF_IDLE;
383 * If the hold buffer is empty, then do a timed sleep, which
384 * ends when the timeout expires or when enough packets
385 * have arrived to fill the store buffer.
387 while (d->bd_hbuf == NULL) {
388 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
390 * A packet(s) either arrived since the previous
391 * read or arrived while we were asleep.
392 * Rotate the buffers and return what's here.
399 * No data is available, check to see if the bpf device
400 * is still pointed at a real interface. If not, return
401 * ENXIO so that the userland process knows to rebind
402 * it before using it again.
404 if (d->bd_bif == NULL) {
409 if (ap->a_ioflag & IO_NDELAY) {
413 error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
414 if (error == EINTR || error == ERESTART) {
418 if (error == EWOULDBLOCK) {
420 * On a timeout, return what's in the buffer,
421 * which may be nothing. If there is something
422 * in the store buffer, we can rotate the buffers.
426 * We filled up the buffer in between
427 * getting the timeout and arriving
428 * here, so we don't need to rotate.
432 if (d->bd_slen == 0) {
441 * At this point, we know we have something in the hold slot.
446 * Move data from hold buffer into user space.
447 * We know the entire buffer is transferred since
448 * we checked above that the read buffer is bpf_bufsize bytes.
450 error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
453 d->bd_fbuf = d->bd_hbuf;
463 * If there are processes sleeping on this descriptor, wake them up.
466 bpf_wakeup(struct bpf_d *d)
468 if (d->bd_state == BPF_WAITING) {
469 callout_stop(&d->bd_callout);
470 d->bd_state = BPF_IDLE;
473 if (d->bd_async && d->bd_sig && d->bd_sigio)
474 pgsigio(d->bd_sigio, d->bd_sig, 0);
477 selwakeup(&d->bd_sel);
480 d->bd_sel.si_pid = 0;
484 bpf_timed_out(void *arg)
486 struct bpf_d *d = (struct bpf_d *)arg;
489 if (d->bd_state == BPF_WAITING) {
490 d->bd_state = BPF_TIMED_OUT;
498 bpfwrite(struct dev_write_args *ap)
500 cdev_t dev = ap->a_head.a_dev;
501 struct bpf_d *d = dev->si_drv1;
505 static struct sockaddr dst;
508 if (d->bd_bif == NULL)
511 ifp = d->bd_bif->bif_ifp;
513 if (ap->a_uio->uio_resid == 0)
516 error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
521 if (datlen > ifp->if_mtu) {
527 dst.sa_family = pseudo_AF_HDRCMPLT;
530 lwkt_serialize_enter(ifp->if_serializer);
531 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)NULL);
532 lwkt_serialize_exit(ifp->if_serializer);
535 * The driver frees the mbuf.
541 * Reset a descriptor by flushing its packet buffer and clearing the
542 * receive and drop counts. Should be called at splimp.
545 reset_d(struct bpf_d *d)
548 /* Free the hold buffer. */
549 d->bd_fbuf = d->bd_hbuf;
559 * FIONREAD Check for read packet available.
560 * SIOCGIFADDR Get interface address - convenient hook to driver.
561 * BIOCGBLEN Get buffer len [for read()].
562 * BIOCSETF Set ethernet read filter.
563 * BIOCFLUSH Flush read packet buffer.
564 * BIOCPROMISC Put interface into promiscuous mode.
565 * BIOCGDLT Get link layer type.
566 * BIOCGETIF Get interface name.
567 * BIOCSETIF Set interface.
568 * BIOCSRTIMEOUT Set read timeout.
569 * BIOCGRTIMEOUT Get read timeout.
570 * BIOCGSTATS Get packet stats.
571 * BIOCIMMEDIATE Set immediate mode.
572 * BIOCVERSION Get filter language version.
573 * BIOCGHDRCMPLT Get "header already complete" flag
574 * BIOCSHDRCMPLT Set "header already complete" flag
575 * BIOCGSEESENT Get "see packets sent" flag
576 * BIOCSSEESENT Set "see packets sent" flag
580 bpfioctl(struct dev_ioctl_args *ap)
582 cdev_t dev = ap->a_head.a_dev;
583 struct bpf_d *d = dev->si_drv1;
587 if (d->bd_state == BPF_WAITING)
588 callout_stop(&d->bd_callout);
589 d->bd_state = BPF_IDLE;
598 * Check for read packet available.
610 *(int *)ap->a_data = n;
618 if (d->bd_bif == NULL)
621 ifp = d->bd_bif->bif_ifp;
622 lwkt_serialize_enter(ifp->if_serializer);
623 error = ifp->if_ioctl(ifp, ap->a_cmd,
624 ap->a_data, ap->a_cred);
625 lwkt_serialize_exit(ifp->if_serializer);
631 * Get buffer len [for read()].
634 *(u_int *)ap->a_data = d->bd_bufsize;
644 u_int size = *(u_int *)ap->a_data;
646 if (size > bpf_maxbufsize)
647 *(u_int *)ap->a_data = size = bpf_maxbufsize;
648 else if (size < BPF_MINBUFSIZE)
649 *(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
650 d->bd_bufsize = size;
655 * Set link layer read filter.
658 error = bpf_setf(d, (struct bpf_program *)ap->a_data);
662 * Flush read packet buffer.
671 * Put interface into promiscuous mode.
674 if (d->bd_bif == NULL) {
676 * No interface attached yet.
682 if (d->bd_promisc == 0) {
683 error = ifpromisc(d->bd_bif->bif_ifp, 1);
691 * Get device parameters.
694 if (d->bd_bif == NULL)
697 *(u_int *)ap->a_data = d->bd_bif->bif_dlt;
701 * Get a list of supported data link types.
704 if (d->bd_bif == NULL)
707 error = bpf_getdltlist(d, (struct bpf_dltlist *)ap->a_data);
711 * Set data link type.
714 if (d->bd_bif == NULL)
717 error = bpf_setdlt(d, *(u_int *)ap->a_data);
721 * Get interface name.
724 if (d->bd_bif == NULL) {
727 struct ifnet *const ifp = d->bd_bif->bif_ifp;
728 struct ifreq *const ifr = (struct ifreq *)ap->a_data;
730 strlcpy(ifr->ifr_name, ifp->if_xname,
731 sizeof ifr->ifr_name);
739 error = bpf_setif(d, (struct ifreq *)ap->a_data);
747 struct timeval *tv = (struct timeval *)ap->a_data;
750 * Subtract 1 tick from tvtohz() since this isn't
753 if ((error = itimerfix(tv)) == 0)
754 d->bd_rtout = tvtohz_low(tv);
763 struct timeval *tv = (struct timeval *)ap->a_data;
765 tv->tv_sec = d->bd_rtout / hz;
766 tv->tv_usec = (d->bd_rtout % hz) * tick;
775 struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
777 bs->bs_recv = d->bd_rcount;
778 bs->bs_drop = d->bd_dcount;
783 * Set immediate mode.
786 d->bd_immediate = *(u_int *)ap->a_data;
791 struct bpf_version *bv = (struct bpf_version *)ap->a_data;
793 bv->bv_major = BPF_MAJOR_VERSION;
794 bv->bv_minor = BPF_MINOR_VERSION;
799 * Get "header already complete" flag
802 *(u_int *)ap->a_data = d->bd_hdrcmplt;
806 * Set "header already complete" flag
809 d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
813 * Get "see sent packets" flag
816 *(u_int *)ap->a_data = d->bd_seesent;
820 * Set "see sent packets" flag
823 d->bd_seesent = *(u_int *)ap->a_data;
826 case FIOASYNC: /* Send signal on receive packets */
827 d->bd_async = *(int *)ap->a_data;
831 error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
835 *(int *)ap->a_data = fgetown(d->bd_sigio);
838 /* This is deprecated, FIOSETOWN should be used instead. */
840 error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
843 /* This is deprecated, FIOGETOWN should be used instead. */
845 *(int *)ap->a_data = -fgetown(d->bd_sigio);
848 case BIOCSRSIG: /* Set receive signal */
852 sig = *(u_int *)ap->a_data;
861 *(u_int *)ap->a_data = d->bd_sig;
868 * Set d's packet filter program to fp. If this file already has a filter,
869 * free it and replace it. Returns EINVAL for bogus requests.
872 bpf_setf(struct bpf_d *d, struct bpf_program *fp)
874 struct bpf_insn *fcode, *old;
878 if (fp->bf_insns == NULL) {
890 if (flen > BPF_MAXINSNS)
893 size = flen * sizeof *fp->bf_insns;
894 fcode = (struct bpf_insn *)kmalloc(size, M_BPF, M_WAITOK);
895 if (copyin(fp->bf_insns, fcode, size) == 0 &&
896 bpf_validate(fcode, (int)flen)) {
898 d->bd_filter = fcode;
911 * Detach a file from its current interface (if attached at all) and attach
912 * to the interface indicated by the name stored in ifr.
913 * Return an errno or 0.
916 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
920 struct ifnet *theywant;
922 theywant = ifunit(ifr->ifr_name);
923 if (theywant == NULL)
927 * Look through attached interfaces for the named one.
929 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
930 struct ifnet *ifp = bp->bif_ifp;
932 if (ifp == NULL || ifp != theywant)
934 /* skip additional entry */
935 if (bp->bif_driverp != &ifp->if_bpf)
938 * We found the requested interface.
939 * If it's not up, return an error.
940 * Allocate the packet buffers if we need to.
941 * If we're already attached to requested interface,
942 * just flush the buffer.
944 if (!(ifp->if_flags & IFF_UP))
947 if (d->bd_sbuf == NULL) {
948 error = bpf_allocbufs(d);
953 if (bp != d->bd_bif) {
954 if (d->bd_bif != NULL) {
956 * Detach if attached to something else.
973 * Support for select() and poll() system calls
975 * Return true iff the specific operation will not block indefinitely.
976 * Otherwise, return false but make a note that a selwakeup() must be done.
979 bpfpoll(struct dev_poll_args *ap)
981 cdev_t dev = ap->a_head.a_dev;
986 if (d->bd_bif == NULL)
989 revents = ap->a_events & (POLLOUT | POLLWRNORM);
991 if (ap->a_events & (POLLIN | POLLRDNORM)) {
993 * An imitation of the FIONREAD ioctl code.
994 * XXX not quite. An exact imitation:
995 * if (d->b_slen != 0 ||
996 * (d->bd_hbuf != NULL && d->bd_hlen != 0)
998 if (d->bd_hlen != 0 ||
999 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1001 revents |= ap->a_events & (POLLIN | POLLRDNORM);
1003 selrecord(curthread, &d->bd_sel);
1004 /* Start the read timeout if necessary. */
1005 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1006 callout_reset(&d->bd_callout, d->bd_rtout,
1008 d->bd_state = BPF_WAITING;
1013 ap->a_events = revents;
1018 * Process the packet pkt of length pktlen. The packet is parsed
1019 * by each listener's filter, and if accepted, stashed into the
1020 * corresponding buffer.
1023 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1031 * Note that the ipl does not have to be raised at this point.
1032 * The only problem that could arise here is that if two different
1033 * interfaces shared any data. This is not the case.
1035 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1037 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
1043 catchpacket(d, pkt, pktlen, slen, ovbcopy, &tv);
1049 * Copy data from an mbuf chain into a buffer. This code is derived
1050 * from m_copydata in sys/uipc_mbuf.c.
1053 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1055 const struct mbuf *m;
1064 count = min(m->m_len, len);
1065 bcopy(mtod(m, void *), dst, count);
1073 * Process the packet in the mbuf chain m. The packet is parsed by each
1074 * listener's filter, and if accepted, stashed into the corresponding
1078 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1086 /* Don't compute pktlen, if no descriptor is attached. */
1087 if (SLIST_EMPTY(&bp->bif_dlist))
1091 for (m0 = m; m0 != NULL; m0 = m0->m_next)
1092 pktlen += m0->m_len;
1094 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1095 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1098 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0);
1104 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy,
1111 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1115 KKASSERT(family != AF_UNSPEC);
1117 family4 = (u_int)family;
1118 bpf_ptap(bp, m, &family4, sizeof(family4));
1122 * Process the packet in the mbuf chain m with the header in m prepended.
1123 * The packet is parsed by each listener's filter, and if accepted,
1124 * stashed into the corresponding buffer.
1127 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1132 * Craft on-stack mbuf suitable for passing to bpf_mtap.
1133 * Note that we cut corners here; we only setup what's
1134 * absolutely needed--this mbuf should never go anywhere else.
1137 mb.m_data = __DECONST(void *, data); /* LINTED */
1144 * Move the packet data from interface memory (pkt) into the
1145 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1146 * otherwise 0. "copy" is the routine called to do the actual data
1147 * transfer. bcopy is passed in to copy contiguous chunks, while
1148 * bpf_mcopy is passed in to copy mbuf chains. In the latter case,
1149 * pkt is really an mbuf.
1152 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1153 void (*cpfn)(const void *, void *, size_t),
1154 const struct timeval *tv)
1158 int hdrlen = d->bd_bif->bif_hdrlen;
1160 * Figure out how many bytes to move. If the packet is
1161 * greater or equal to the snapshot length, transfer that
1162 * much. Otherwise, transfer the whole packet (unless
1163 * we hit the buffer size limit).
1165 totlen = hdrlen + min(snaplen, pktlen);
1166 if (totlen > d->bd_bufsize)
1167 totlen = d->bd_bufsize;
1170 * Round up the end of the previous packet to the next longword.
1172 curlen = BPF_WORDALIGN(d->bd_slen);
1173 if (curlen + totlen > d->bd_bufsize) {
1175 * This packet will overflow the storage buffer.
1176 * Rotate the buffers if we can, then wakeup any
1179 if (d->bd_fbuf == NULL) {
1181 * We haven't completed the previous read yet,
1182 * so drop the packet.
1191 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
1193 * Immediate mode is set, or the read timeout has
1194 * already expired during a select call. A packet
1195 * arrived, so the reader should be woken up.
1200 * Append the bpf header.
1202 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1203 hp->bh_tstamp = *tv;
1204 hp->bh_datalen = pktlen;
1205 hp->bh_hdrlen = hdrlen;
1207 * Copy the packet data into the store buffer and update its length.
1209 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1210 d->bd_slen = curlen + totlen;
1214 * Initialize all nonzero fields of a descriptor.
1217 bpf_allocbufs(struct bpf_d *d)
1219 d->bd_fbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1220 if (d->bd_fbuf == NULL)
1223 d->bd_sbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1224 if (d->bd_sbuf == NULL) {
1225 kfree(d->bd_fbuf, M_BPF);
1234 * Free buffers currently in use by a descriptor.
1238 bpf_freed(struct bpf_d *d)
1241 * We don't need to lock out interrupts since this descriptor has
1242 * been detached from its interface and it yet hasn't been marked
1245 if (d->bd_sbuf != NULL) {
1246 kfree(d->bd_sbuf, M_BPF);
1247 if (d->bd_hbuf != NULL)
1248 kfree(d->bd_hbuf, M_BPF);
1249 if (d->bd_fbuf != NULL)
1250 kfree(d->bd_fbuf, M_BPF);
1253 kfree(d->bd_filter, M_BPF);
1257 * Attach an interface to bpf. ifp is a pointer to the structure
1258 * defining the interface to be attached, dlt is the link layer type,
1259 * and hdrlen is the fixed size of the link header (variable length
1260 * headers are not yet supported).
1263 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1265 bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1269 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1273 bp = kmalloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1275 SLIST_INIT(&bp->bif_dlist);
1278 bp->bif_driverp = driverp;
1279 *bp->bif_driverp = NULL;
1281 bp->bif_next = bpf_iflist;
1285 * Compute the length of the bpf header. This is not necessarily
1286 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1287 * that the network layer header begins on a longword boundary (for
1288 * performance reasons and to alleviate alignment restrictions).
1290 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1293 if_printf(ifp, "bpf attached\n");
1297 * Detach bpf from an interface. This involves detaching each descriptor
1298 * associated with the interface, and leaving bd_bif NULL. Notify each
1299 * descriptor as it's detached so that any sleepers wake up and get
1303 bpfdetach(struct ifnet *ifp)
1305 struct bpf_if *bp, *bp_prev;
1310 /* Locate BPF interface information */
1312 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1313 if (ifp == bp->bif_ifp)
1318 /* Interface wasn't attached */
1319 if (bp->bif_ifp == NULL) {
1321 printf("bpfdetach: %s was not attached\n", ifp->if_xname);
1325 while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1330 if (bp_prev != NULL)
1331 bp_prev->bif_next = bp->bif_next;
1333 bpf_iflist = bp->bif_next;
1341 * Get a list of available data link type of the interface.
1344 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1350 ifp = d->bd_bif->bif_ifp;
1353 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
1354 if (bp->bif_ifp != ifp)
1356 if (bfl->bfl_list != NULL) {
1357 if (n >= bfl->bfl_len) {
1360 error = copyout(&bp->bif_dlt,
1361 bfl->bfl_list + n, sizeof(u_int));
1370 * Set the data link type of a BPF instance.
1373 bpf_setdlt(struct bpf_d *d, u_int dlt)
1375 int error, opromisc;
1379 if (d->bd_bif->bif_dlt == dlt)
1381 ifp = d->bd_bif->bif_ifp;
1382 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
1383 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1387 opromisc = d->bd_promisc;
1393 error = ifpromisc(bp->bif_ifp, 1);
1395 if_printf(bp->bif_ifp,
1396 "bpf_setdlt: ifpromisc failed (%d)\n",
1403 return(bp == NULL ? EINVAL : 0);
1407 bpf_drvinit(void *unused)
1409 dev_ops_add(&bpf_ops, 0, 0);
1412 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1416 * NOP stubs to allow bpf-using drivers to load and function.
1418 * A 'better' implementation would allow the core bpf functionality
1419 * to be loaded at runtime.
1423 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1428 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1433 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1438 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1443 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1448 bpfdetach(struct ifnet *ifp)
1453 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1455 return -1; /* "no filter" behaviour */