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 1.50 2008/09/23 11:28:49 sephe 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>
70 #include <net/netmsg2.h>
72 #include <netinet/in.h>
73 #include <netinet/if_ether.h>
74 #include <sys/kernel.h>
75 #include <sys/sysctl.h>
77 #include <sys/devfs.h>
79 struct netmsg_bpf_output {
80 struct netmsg nm_netmsg;
83 struct sockaddr *nm_dst;
86 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
87 DEVFS_DECLARE_CLONE_BITMAP(bpf);
90 #define BPF_PREALLOCATED_UNITS 4
92 #define BPF_PREALLOCATED_UNITS NBPF
98 * The default read buffer size is patchable.
100 static int bpf_bufsize = BPF_DEFAULTBUFSIZE;
101 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
102 &bpf_bufsize, 0, "");
103 int bpf_maxbufsize = BPF_MAXBUFSIZE;
104 SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
105 &bpf_maxbufsize, 0, "");
108 * bpf_iflist is the list of interfaces; each corresponds to an ifnet
110 static struct bpf_if *bpf_iflist;
112 static int bpf_allocbufs(struct bpf_d *);
113 static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
114 static void bpf_detachd(struct bpf_d *d);
115 static void bpf_resetd(struct bpf_d *);
116 static void bpf_freed(struct bpf_d *);
117 static void bpf_mcopy(const void *, void *, size_t);
118 static int bpf_movein(struct uio *, int, struct mbuf **,
119 struct sockaddr *, int *, struct bpf_insn *);
120 static int bpf_setif(struct bpf_d *, struct ifreq *);
121 static void bpf_timed_out(void *);
122 static void bpf_wakeup(struct bpf_d *);
123 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
124 void (*)(const void *, void *, size_t),
125 const struct timeval *);
126 static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
127 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
128 static int bpf_setdlt(struct bpf_d *, u_int);
129 static void bpf_drvinit(void *unused);
131 static d_open_t bpfopen;
132 static d_clone_t bpfclone;
133 static d_close_t bpfclose;
134 static d_read_t bpfread;
135 static d_write_t bpfwrite;
136 static d_ioctl_t bpfioctl;
137 static d_poll_t bpfpoll;
139 #define CDEV_MAJOR 23
140 static struct dev_ops bpf_ops = {
141 { "bpf", CDEV_MAJOR, 0 },
152 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp,
153 struct sockaddr *sockp, int *datlen, struct bpf_insn *wfilter)
165 * Build a sockaddr based on the data link layer type.
166 * We do this at this level because the ethernet header
167 * is copied directly into the data field of the sockaddr.
168 * In the case of SLIP, there is no header and the packet
169 * is forwarded as is.
170 * Also, we are careful to leave room at the front of the mbuf
171 * for the link level header.
175 sockp->sa_family = AF_INET;
180 sockp->sa_family = AF_UNSPEC;
181 /* XXX Would MAXLINKHDR be better? */
182 hlen = sizeof(struct ether_header);
187 sockp->sa_family = AF_UNSPEC;
191 case DLT_ATM_RFC1483:
193 * en atm driver requires 4-byte atm pseudo header.
194 * though it isn't standard, vpi:vci needs to be
197 sockp->sa_family = AF_UNSPEC;
198 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
202 sockp->sa_family = AF_UNSPEC;
203 hlen = 4; /* This should match PPP_HDRLEN */
210 len = uio->uio_resid;
211 *datlen = len - hlen;
212 if ((unsigned)len > MCLBYTES)
215 m = m_getl(len, MB_WAIT, MT_DATA, M_PKTHDR, NULL);
218 m->m_pkthdr.len = m->m_len = len;
219 m->m_pkthdr.rcvif = NULL;
222 if (m->m_len < hlen) {
227 error = uiomove(mtod(m, u_char *), len, uio);
231 slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
238 * Make room for link header, and copy it to sockaddr.
241 bcopy(m->m_data, sockp->sa_data, hlen);
242 m->m_pkthdr.len -= hlen;
244 m->m_data += hlen; /* XXX */
253 * Attach file to the bpf interface, i.e. make d listen on bp.
254 * Must be called at splimp.
257 bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
260 * Point d at bp, and add d to the interface's list of listeners.
261 * Finally, point the driver's bpf cookie at the interface so
262 * it will divert packets to bpf.
265 SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
266 *bp->bif_driverp = bp;
270 * Detach a file from its interface.
273 bpf_detachd(struct bpf_d *d)
282 /* Remove d from the interface's descriptor list. */
283 SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next);
285 if (SLIST_EMPTY(&bp->bif_dlist)) {
287 * Let the driver know that there are no more listeners.
289 *bp->bif_driverp = NULL;
293 * Check if this descriptor had requested promiscuous mode.
294 * If so, turn it off.
298 error = ifpromisc(ifp, 0);
299 if (error != 0 && error != ENXIO) {
301 * ENXIO can happen if a pccard is unplugged,
302 * Something is really wrong if we were able to put
303 * the driver into promiscuous mode, but can't
306 if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n",
313 * Open ethernet device. Returns ENXIO for illegal minor device number,
314 * EBUSY if file is open by another process.
318 bpfopen(struct dev_open_args *ap)
320 cdev_t dev = ap->a_head.a_dev;
323 if (ap->a_cred->cr_prison)
328 * Each minor can be opened by only one process. If the requested
329 * minor is in use, return EBUSY.
334 MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO);
336 d->bd_bufsize = bpf_bufsize;
339 callout_init(&d->bd_callout);
344 bpfclone(struct dev_clone_args *ap)
348 unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(bpf), 0);
349 ap->a_dev = make_only_dev(&bpf_ops, unit, 0, 0, 0600, "bpf%d", unit);
355 * Close the descriptor by detaching it from its interface,
356 * deallocating its buffers, and marking it free.
360 bpfclose(struct dev_close_args *ap)
362 cdev_t dev = ap->a_head.a_dev;
363 struct bpf_d *d = dev->si_drv1;
365 funsetown(d->bd_sigio);
367 if (d->bd_state == BPF_WAITING)
368 callout_stop(&d->bd_callout);
369 d->bd_state = BPF_IDLE;
370 if (d->bd_bif != NULL)
375 if (dev->si_uminor >= BPF_PREALLOCATED_UNITS) {
376 devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(bpf), dev->si_uminor);
384 * Rotate the packet buffers in descriptor d. Move the store buffer
385 * into the hold slot, and the free buffer into the store slot.
386 * Zero the length of the new store buffer.
388 #define ROTATE_BUFFERS(d) \
389 (d)->bd_hbuf = (d)->bd_sbuf; \
390 (d)->bd_hlen = (d)->bd_slen; \
391 (d)->bd_sbuf = (d)->bd_fbuf; \
395 * bpfread - read next chunk of packets from buffers
398 bpfread(struct dev_read_args *ap)
400 cdev_t dev = ap->a_head.a_dev;
401 struct bpf_d *d = dev->si_drv1;
406 * Restrict application to use a buffer the same size as
409 if (ap->a_uio->uio_resid != d->bd_bufsize)
413 if (d->bd_state == BPF_WAITING)
414 callout_stop(&d->bd_callout);
415 timed_out = (d->bd_state == BPF_TIMED_OUT);
416 d->bd_state = BPF_IDLE;
418 * If the hold buffer is empty, then do a timed sleep, which
419 * ends when the timeout expires or when enough packets
420 * have arrived to fill the store buffer.
422 while (d->bd_hbuf == NULL) {
423 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
425 * A packet(s) either arrived since the previous
426 * read or arrived while we were asleep.
427 * Rotate the buffers and return what's here.
434 * No data is available, check to see if the bpf device
435 * is still pointed at a real interface. If not, return
436 * ENXIO so that the userland process knows to rebind
437 * it before using it again.
439 if (d->bd_bif == NULL) {
444 if (ap->a_ioflag & IO_NDELAY) {
448 error = tsleep(d, PCATCH, "bpf", d->bd_rtout);
449 if (error == EINTR || error == ERESTART) {
453 if (error == EWOULDBLOCK) {
455 * On a timeout, return what's in the buffer,
456 * which may be nothing. If there is something
457 * in the store buffer, we can rotate the buffers.
461 * We filled up the buffer in between
462 * getting the timeout and arriving
463 * here, so we don't need to rotate.
467 if (d->bd_slen == 0) {
476 * At this point, we know we have something in the hold slot.
481 * Move data from hold buffer into user space.
482 * We know the entire buffer is transferred since
483 * we checked above that the read buffer is bpf_bufsize bytes.
485 error = uiomove(d->bd_hbuf, d->bd_hlen, ap->a_uio);
488 d->bd_fbuf = d->bd_hbuf;
498 * If there are processes sleeping on this descriptor, wake them up.
501 bpf_wakeup(struct bpf_d *d)
503 if (d->bd_state == BPF_WAITING) {
504 callout_stop(&d->bd_callout);
505 d->bd_state = BPF_IDLE;
508 if (d->bd_async && d->bd_sig && d->bd_sigio)
509 pgsigio(d->bd_sigio, d->bd_sig, 0);
512 selwakeup(&d->bd_sel);
515 d->bd_sel.si_pid = 0;
519 bpf_timed_out(void *arg)
521 struct bpf_d *d = (struct bpf_d *)arg;
524 if (d->bd_state == BPF_WAITING) {
525 d->bd_state = BPF_TIMED_OUT;
533 bpf_output_dispatch(struct netmsg *nmsg)
535 struct netmsg_bpf_output *bmsg = (struct netmsg_bpf_output *)nmsg;
536 struct ifnet *ifp = bmsg->nm_ifp;
540 * The driver frees the mbuf.
542 error = ifp->if_output(ifp, bmsg->nm_mbuf, bmsg->nm_dst, NULL);
543 lwkt_replymsg(&nmsg->nm_lmsg, error);
547 bpfwrite(struct dev_write_args *ap)
549 cdev_t dev = ap->a_head.a_dev;
550 struct bpf_d *d = dev->si_drv1;
556 struct netmsg_bpf_output bmsg;
558 if (d->bd_bif == NULL)
561 ifp = d->bd_bif->bif_ifp;
563 if (ap->a_uio->uio_resid == 0)
566 error = bpf_movein(ap->a_uio, (int)d->bd_bif->bif_dlt, &m,
567 &dst, &datlen, d->bd_wfilter);
571 if (datlen > ifp->if_mtu) {
577 dst.sa_family = pseudo_AF_HDRCMPLT;
579 netmsg_init(&bmsg.nm_netmsg, &curthread->td_msgport, MSGF_MPSAFE,
580 bpf_output_dispatch);
585 return lwkt_domsg(cpu_portfn(0), &bmsg.nm_netmsg.nm_lmsg, 0);
589 * Reset a descriptor by flushing its packet buffer and clearing the
590 * receive and drop counts. Should be called at splimp.
593 bpf_resetd(struct bpf_d *d)
596 /* Free the hold buffer. */
597 d->bd_fbuf = d->bd_hbuf;
607 * FIONREAD Check for read packet available.
608 * SIOCGIFADDR Get interface address - convenient hook to driver.
609 * BIOCGBLEN Get buffer len [for read()].
610 * BIOCSETF Set ethernet read filter.
611 * BIOCSETWF Set ethernet write filter.
612 * BIOCFLUSH Flush read packet buffer.
613 * BIOCPROMISC Put interface into promiscuous mode.
614 * BIOCGDLT Get link layer type.
615 * BIOCGETIF Get interface name.
616 * BIOCSETIF Set interface.
617 * BIOCSRTIMEOUT Set read timeout.
618 * BIOCGRTIMEOUT Get read timeout.
619 * BIOCGSTATS Get packet stats.
620 * BIOCIMMEDIATE Set immediate mode.
621 * BIOCVERSION Get filter language version.
622 * BIOCGHDRCMPLT Get "header already complete" flag
623 * BIOCSHDRCMPLT Set "header already complete" flag
624 * BIOCGSEESENT Get "see packets sent" flag
625 * BIOCSSEESENT Set "see packets sent" flag
626 * BIOCLOCK Set "locked" flag
630 bpfioctl(struct dev_ioctl_args *ap)
632 cdev_t dev = ap->a_head.a_dev;
633 struct bpf_d *d = dev->si_drv1;
637 if (d->bd_state == BPF_WAITING)
638 callout_stop(&d->bd_callout);
639 d->bd_state = BPF_IDLE;
642 if (d->bd_locked == 1) {
670 * Check for read packet available.
682 *(int *)ap->a_data = n;
690 if (d->bd_bif == NULL) {
693 ifp = d->bd_bif->bif_ifp;
694 ifnet_serialize_all(ifp);
695 error = ifp->if_ioctl(ifp, ap->a_cmd,
696 ap->a_data, ap->a_cred);
697 ifnet_deserialize_all(ifp);
703 * Get buffer len [for read()].
706 *(u_int *)ap->a_data = d->bd_bufsize;
713 if (d->bd_bif != NULL) {
716 u_int size = *(u_int *)ap->a_data;
718 if (size > bpf_maxbufsize)
719 *(u_int *)ap->a_data = size = bpf_maxbufsize;
720 else if (size < BPF_MINBUFSIZE)
721 *(u_int *)ap->a_data = size = BPF_MINBUFSIZE;
722 d->bd_bufsize = size;
727 * Set link layer read filter.
731 error = bpf_setf(d, (struct bpf_program *)ap->a_data,
736 * Flush read packet buffer.
745 * Put interface into promiscuous mode.
748 if (d->bd_bif == NULL) {
750 * No interface attached yet.
756 if (d->bd_promisc == 0) {
757 error = ifpromisc(d->bd_bif->bif_ifp, 1);
765 * Get device parameters.
768 if (d->bd_bif == NULL)
771 *(u_int *)ap->a_data = d->bd_bif->bif_dlt;
775 * Get a list of supported data link types.
778 if (d->bd_bif == NULL) {
781 error = bpf_getdltlist(d,
782 (struct bpf_dltlist *)ap->a_data);
787 * Set data link type.
790 if (d->bd_bif == NULL)
793 error = bpf_setdlt(d, *(u_int *)ap->a_data);
797 * Get interface name.
800 if (d->bd_bif == NULL) {
803 struct ifnet *const ifp = d->bd_bif->bif_ifp;
804 struct ifreq *const ifr = (struct ifreq *)ap->a_data;
806 strlcpy(ifr->ifr_name, ifp->if_xname,
807 sizeof ifr->ifr_name);
815 error = bpf_setif(d, (struct ifreq *)ap->a_data);
823 struct timeval *tv = (struct timeval *)ap->a_data;
826 * Subtract 1 tick from tvtohz() since this isn't
829 if ((error = itimerfix(tv)) == 0)
830 d->bd_rtout = tvtohz_low(tv);
839 struct timeval *tv = (struct timeval *)ap->a_data;
841 tv->tv_sec = d->bd_rtout / hz;
842 tv->tv_usec = (d->bd_rtout % hz) * tick;
851 struct bpf_stat *bs = (struct bpf_stat *)ap->a_data;
853 bs->bs_recv = d->bd_rcount;
854 bs->bs_drop = d->bd_dcount;
859 * Set immediate mode.
862 d->bd_immediate = *(u_int *)ap->a_data;
867 struct bpf_version *bv = (struct bpf_version *)ap->a_data;
869 bv->bv_major = BPF_MAJOR_VERSION;
870 bv->bv_minor = BPF_MINOR_VERSION;
875 * Get "header already complete" flag
878 *(u_int *)ap->a_data = d->bd_hdrcmplt;
882 * Set "header already complete" flag
885 d->bd_hdrcmplt = *(u_int *)ap->a_data ? 1 : 0;
889 * Get "see sent packets" flag
892 *(u_int *)ap->a_data = d->bd_seesent;
896 * Set "see sent packets" flag
899 d->bd_seesent = *(u_int *)ap->a_data;
902 case FIOASYNC: /* Send signal on receive packets */
903 d->bd_async = *(int *)ap->a_data;
907 error = fsetown(*(int *)ap->a_data, &d->bd_sigio);
911 *(int *)ap->a_data = fgetown(d->bd_sigio);
914 /* This is deprecated, FIOSETOWN should be used instead. */
916 error = fsetown(-(*(int *)ap->a_data), &d->bd_sigio);
919 /* This is deprecated, FIOGETOWN should be used instead. */
921 *(int *)ap->a_data = -fgetown(d->bd_sigio);
924 case BIOCSRSIG: /* Set receive signal */
928 sig = *(u_int *)ap->a_data;
937 *(u_int *)ap->a_data = d->bd_sig;
947 * Set d's packet filter program to fp. If this file already has a filter,
948 * free it and replace it. Returns EINVAL for bogus requests.
951 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
953 struct bpf_insn *fcode, *old;
954 u_int wfilter, flen, size;
956 if (cmd == BIOCSETWF) {
963 if (fp->bf_insns == NULL) {
968 d->bd_wfilter = NULL;
970 d->bd_rfilter = NULL;
978 if (flen > BPF_MAXINSNS)
981 size = flen * sizeof *fp->bf_insns;
982 fcode = (struct bpf_insn *)kmalloc(size, M_BPF, M_WAITOK);
983 if (copyin(fp->bf_insns, fcode, size) == 0 &&
984 bpf_validate(fcode, (int)flen)) {
987 d->bd_wfilter = fcode;
989 d->bd_rfilter = fcode;
1002 * Detach a file from its current interface (if attached at all) and attach
1003 * to the interface indicated by the name stored in ifr.
1004 * Return an errno or 0.
1007 bpf_setif(struct bpf_d *d, struct ifreq *ifr)
1011 struct ifnet *theywant;
1013 theywant = ifunit(ifr->ifr_name);
1014 if (theywant == NULL)
1018 * Look through attached interfaces for the named one.
1020 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1021 struct ifnet *ifp = bp->bif_ifp;
1023 if (ifp == NULL || ifp != theywant)
1025 /* skip additional entry */
1026 if (bp->bif_driverp != &ifp->if_bpf)
1029 * We found the requested interface.
1030 * If it's not up, return an error.
1031 * Allocate the packet buffers if we need to.
1032 * If we're already attached to requested interface,
1033 * just flush the buffer.
1035 if (!(ifp->if_flags & IFF_UP))
1038 if (d->bd_sbuf == NULL) {
1039 error = bpf_allocbufs(d);
1044 if (bp != d->bd_bif) {
1045 if (d->bd_bif != NULL) {
1047 * Detach if attached to something else.
1064 * Support for select() and poll() system calls
1066 * Return true iff the specific operation will not block indefinitely.
1067 * Otherwise, return false but make a note that a selwakeup() must be done.
1070 bpfpoll(struct dev_poll_args *ap)
1072 cdev_t dev = ap->a_head.a_dev;
1077 if (d->bd_bif == NULL)
1080 revents = ap->a_events & (POLLOUT | POLLWRNORM);
1082 if (ap->a_events & (POLLIN | POLLRDNORM)) {
1084 * An imitation of the FIONREAD ioctl code.
1085 * XXX not quite. An exact imitation:
1086 * if (d->b_slen != 0 ||
1087 * (d->bd_hbuf != NULL && d->bd_hlen != 0)
1089 if (d->bd_hlen != 0 ||
1090 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
1092 revents |= ap->a_events & (POLLIN | POLLRDNORM);
1094 selrecord(curthread, &d->bd_sel);
1095 /* Start the read timeout if necessary. */
1096 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
1097 callout_reset(&d->bd_callout, d->bd_rtout,
1099 d->bd_state = BPF_WAITING;
1104 ap->a_events = revents;
1109 * Process the packet pkt of length pktlen. The packet is parsed
1110 * by each listener's filter, and if accepted, stashed into the
1111 * corresponding buffer.
1114 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1130 * Note that the ipl does not have to be raised at this point.
1131 * The only problem that could arise here is that if two different
1132 * interfaces shared any data. This is not the case.
1134 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1136 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
1142 catchpacket(d, pkt, pktlen, slen, ovbcopy, &tv);
1150 * Copy data from an mbuf chain into a buffer. This code is derived
1151 * from m_copydata in sys/uipc_mbuf.c.
1154 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len)
1156 const struct mbuf *m;
1165 count = min(m->m_len, len);
1166 bcopy(mtod(m, void *), dst, count);
1174 * Process the packet in the mbuf chain m. The packet is parsed by each
1175 * listener's filter, and if accepted, stashed into the corresponding
1179 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1194 /* Don't compute pktlen, if no descriptor is attached. */
1195 if (SLIST_EMPTY(&bp->bif_dlist)) {
1200 pktlen = m_lengthm(m, NULL);
1202 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) {
1203 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
1206 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
1212 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy,
1221 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family)
1225 KKASSERT(family != AF_UNSPEC);
1227 family4 = (u_int)family;
1228 bpf_ptap(bp, m, &family4, sizeof(family4));
1232 * Process the packet in the mbuf chain m with the header in m prepended.
1233 * The packet is parsed by each listener's filter, and if accepted,
1234 * stashed into the corresponding buffer.
1237 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1242 * Craft on-stack mbuf suitable for passing to bpf_mtap.
1243 * Note that we cut corners here; we only setup what's
1244 * absolutely needed--this mbuf should never go anywhere else.
1247 mb.m_data = __DECONST(void *, data); /* LINTED */
1249 mb.m_pkthdr.rcvif = m->m_pkthdr.rcvif;
1255 * Move the packet data from interface memory (pkt) into the
1256 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1257 * otherwise 0. "copy" is the routine called to do the actual data
1258 * transfer. bcopy is passed in to copy contiguous chunks, while
1259 * bpf_mcopy is passed in to copy mbuf chains. In the latter case,
1260 * pkt is really an mbuf.
1263 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
1264 void (*cpfn)(const void *, void *, size_t),
1265 const struct timeval *tv)
1269 int hdrlen = d->bd_bif->bif_hdrlen;
1271 * Figure out how many bytes to move. If the packet is
1272 * greater or equal to the snapshot length, transfer that
1273 * much. Otherwise, transfer the whole packet (unless
1274 * we hit the buffer size limit).
1276 totlen = hdrlen + min(snaplen, pktlen);
1277 if (totlen > d->bd_bufsize)
1278 totlen = d->bd_bufsize;
1281 * Round up the end of the previous packet to the next longword.
1283 curlen = BPF_WORDALIGN(d->bd_slen);
1284 if (curlen + totlen > d->bd_bufsize) {
1286 * This packet will overflow the storage buffer.
1287 * Rotate the buffers if we can, then wakeup any
1290 if (d->bd_fbuf == NULL) {
1292 * We haven't completed the previous read yet,
1293 * so drop the packet.
1301 } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) {
1303 * Immediate mode is set, or the read timeout has
1304 * already expired during a select call. A packet
1305 * arrived, so the reader should be woken up.
1311 * Append the bpf header.
1313 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1314 hp->bh_tstamp = *tv;
1315 hp->bh_datalen = pktlen;
1316 hp->bh_hdrlen = hdrlen;
1318 * Copy the packet data into the store buffer and update its length.
1320 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1321 d->bd_slen = curlen + totlen;
1325 * Initialize all nonzero fields of a descriptor.
1328 bpf_allocbufs(struct bpf_d *d)
1330 d->bd_fbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1331 d->bd_sbuf = kmalloc(d->bd_bufsize, M_BPF, M_WAITOK);
1338 * Free buffers and packet filter program currently in use by a descriptor.
1342 bpf_freed(struct bpf_d *d)
1345 * We don't need to lock out interrupts since this descriptor has
1346 * been detached from its interface and it yet hasn't been marked
1349 if (d->bd_sbuf != NULL) {
1350 kfree(d->bd_sbuf, M_BPF);
1351 if (d->bd_hbuf != NULL)
1352 kfree(d->bd_hbuf, M_BPF);
1353 if (d->bd_fbuf != NULL)
1354 kfree(d->bd_fbuf, M_BPF);
1357 kfree(d->bd_rfilter, M_BPF);
1359 kfree(d->bd_wfilter, M_BPF);
1363 * Attach an interface to bpf. ifp is a pointer to the structure
1364 * defining the interface to be attached, dlt is the link layer type,
1365 * and hdrlen is the fixed size of the link header (variable length
1366 * headers are not yet supported).
1369 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1371 bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf);
1375 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1379 bp = kmalloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO);
1381 SLIST_INIT(&bp->bif_dlist);
1384 bp->bif_driverp = driverp;
1385 *bp->bif_driverp = NULL;
1387 bp->bif_next = bpf_iflist;
1391 * Compute the length of the bpf header. This is not necessarily
1392 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1393 * that the network layer header begins on a longword boundary (for
1394 * performance reasons and to alleviate alignment restrictions).
1396 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1399 if_printf(ifp, "bpf attached\n");
1403 * Detach bpf from an interface. This involves detaching each descriptor
1404 * associated with the interface, and leaving bd_bif NULL. Notify each
1405 * descriptor as it's detached so that any sleepers wake up and get
1409 bpfdetach(struct ifnet *ifp)
1411 struct bpf_if *bp, *bp_prev;
1416 /* Locate BPF interface information */
1418 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1419 if (ifp == bp->bif_ifp)
1424 /* Interface wasn't attached */
1425 if (bp->bif_ifp == NULL) {
1427 kprintf("bpfdetach: %s was not attached\n", ifp->if_xname);
1431 while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) {
1436 if (bp_prev != NULL)
1437 bp_prev->bif_next = bp->bif_next;
1439 bpf_iflist = bp->bif_next;
1447 * Get a list of available data link type of the interface.
1450 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
1456 ifp = d->bd_bif->bif_ifp;
1459 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1460 if (bp->bif_ifp != ifp)
1462 if (bfl->bfl_list != NULL) {
1463 if (n >= bfl->bfl_len) {
1466 error = copyout(&bp->bif_dlt,
1467 bfl->bfl_list + n, sizeof(u_int));
1476 * Set the data link type of a BPF instance.
1479 bpf_setdlt(struct bpf_d *d, u_int dlt)
1481 int error, opromisc;
1485 if (d->bd_bif->bif_dlt == dlt)
1487 ifp = d->bd_bif->bif_ifp;
1488 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
1489 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
1493 opromisc = d->bd_promisc;
1499 error = ifpromisc(bp->bif_ifp, 1);
1501 if_printf(bp->bif_ifp,
1502 "bpf_setdlt: ifpromisc failed (%d)\n",
1510 return(bp == NULL ? EINVAL : 0);
1514 bpf_drvinit(void *unused)
1518 make_autoclone_dev(&bpf_ops, &DEVFS_CLONE_BITMAP(bpf),
1519 bpfclone, 0, 0, 0600, "bpf");
1520 for (i = 0; i < BPF_PREALLOCATED_UNITS; i++) {
1521 make_dev(&bpf_ops, i, 0, 0, 0600, "bpf%d", i);
1522 devfs_clone_bitmap_set(&DEVFS_CLONE_BITMAP(bpf), i);
1527 bpf_drvuninit(void *unused)
1529 devfs_clone_handler_del("bpf");
1530 dev_ops_remove_all(&bpf_ops);
1531 devfs_clone_bitmap_uninit(&DEVFS_CLONE_BITMAP(bpf));
1534 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1535 SYSUNINIT(bpfdev, SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvuninit, NULL);
1539 * NOP stubs to allow bpf-using drivers to load and function.
1541 * A 'better' implementation would allow the core bpf functionality
1542 * to be loaded at runtime.
1546 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
1551 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
1556 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen)
1561 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
1566 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
1571 bpfdetach(struct ifnet *ifp)
1576 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
1578 return -1; /* "no filter" behaviour */