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
48 #define inline __inline
51 #include <sys/param.h>
52 #include <sys/systm.h>
54 #include <sys/malloc.h>
58 #include <sys/signalvar.h>
59 #include <sys/filio.h>
60 #include <sys/sockio.h>
61 #include <sys/ttycom.h>
62 #include <sys/filedesc.h>
64 #if defined(sparc) && BSD < 199103
65 #include <sys/stream.h>
69 #include <sys/socket.h>
70 #include <sys/vnode.h>
74 #include <net/bpfdesc.h>
76 #include <netinet/in.h>
77 #include <netinet/if_ether.h>
78 #include <sys/kernel.h>
79 #include <sys/sysctl.h>
81 MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
86 * Older BSDs don't have kernel malloc.
90 static caddr_t bpf_alloc();
91 #include <net/bpf_compat.h>
92 #define BPF_BUFSIZE (MCLBYTES-8)
93 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio)
95 #define BPF_BUFSIZE 4096
96 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio)
99 #define PRINET 26 /* interruptible */
102 * The default read buffer size is patchable.
104 static int bpf_bufsize = BPF_BUFSIZE;
105 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
106 &bpf_bufsize, 0, "");
109 * bpf_iflist is the list of interfaces; each corresponds to an ifnet
111 static struct bpf_if *bpf_iflist;
113 static int bpf_allocbufs __P((struct bpf_d *));
114 static void bpf_attachd __P((struct bpf_d *d, struct bpf_if *bp));
115 static void bpf_detachd __P((struct bpf_d *d));
116 static void bpf_freed __P((struct bpf_d *));
117 static void bpf_ifname __P((struct ifnet *, struct ifreq *));
118 static void bpf_mcopy __P((const void *, void *, size_t));
119 static int bpf_movein __P((struct uio *, int,
120 struct mbuf **, struct sockaddr *, int *));
121 static int bpf_setif __P((struct bpf_d *, struct ifreq *));
123 bpf_wakeup __P((struct bpf_d *));
124 static void catchpacket __P((struct bpf_d *, u_char *, u_int,
125 u_int, void (*)(const void *, void *, size_t)));
126 static void reset_d __P((struct bpf_d *));
127 static int bpf_setf __P((struct bpf_d *, struct bpf_program *));
129 static d_open_t bpfopen;
130 static d_close_t bpfclose;
131 static d_read_t bpfread;
132 static d_write_t bpfwrite;
133 static d_ioctl_t bpfioctl;
134 static d_poll_t bpfpoll;
136 #define CDEV_MAJOR 23
137 static struct cdevsw bpf_cdevsw = {
139 /* close */ bpfclose,
141 /* write */ bpfwrite,
142 /* ioctl */ bpfioctl,
145 /* devtotty */ nodevtotty,
148 /* strategy */ nostrategy,
151 /* maj */ CDEV_MAJOR,
161 bpf_movein(uio, linktype, mp, sockp, datlen)
162 register struct uio *uio;
163 int linktype, *datlen;
164 register struct mbuf **mp;
165 register struct sockaddr *sockp;
173 * Build a sockaddr based on the data link layer type.
174 * We do this at this level because the ethernet header
175 * is copied directly into the data field of the sockaddr.
176 * In the case of SLIP, there is no header and the packet
177 * is forwarded as is.
178 * Also, we are careful to leave room at the front of the mbuf
179 * for the link level header.
184 sockp->sa_family = AF_INET;
189 sockp->sa_family = AF_UNSPEC;
190 /* XXX Would MAXLINKHDR be better? */
191 hlen = sizeof(struct ether_header);
195 #if defined(__FreeBSD__) || defined(__bsdi__)
196 sockp->sa_family = AF_IMPLINK;
199 sockp->sa_family = AF_UNSPEC;
200 /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
207 sockp->sa_family = AF_UNSPEC;
212 case DLT_ATM_RFC1483:
214 * en atm driver requires 4-byte atm pseudo header.
215 * though it isn't standard, vpi:vci needs to be
218 sockp->sa_family = AF_UNSPEC;
219 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
227 len = uio->uio_resid;
228 *datlen = len - hlen;
229 if ((unsigned)len > MCLBYTES)
232 MGETHDR(m, M_WAIT, MT_DATA);
238 if ((m->m_flags & M_EXT) == 0) {
241 if (m->m_len != MCLBYTES) {
247 m->m_pkthdr.len = m->m_len = len;
248 m->m_pkthdr.rcvif = NULL;
251 * Make room for link header.
254 m->m_pkthdr.len -= hlen;
257 m->m_data += hlen; /* XXX */
261 error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio);
265 error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio);
274 * Attach file to the bpf interface, i.e. make d listen on bp.
275 * Must be called at splimp.
283 * Point d at bp, and add d to the interface's list of listeners.
284 * Finally, point the driver's bpf cookie at the interface so
285 * it will divert packets to bpf.
288 d->bd_next = bp->bif_dlist;
291 bp->bif_ifp->if_bpf = bp;
295 * Detach a file from its interface.
306 * Check if this descriptor had requested promiscuous mode.
307 * If so, turn it off.
311 if (ifpromisc(bp->bif_ifp, 0))
313 * Something is really wrong if we were able to put
314 * the driver into promiscuous mode, but can't
317 panic("bpf: ifpromisc failed");
319 /* Remove d from the interface's descriptor list. */
324 panic("bpf_detachd: descriptor not in list");
327 if (bp->bif_dlist == 0)
329 * Let the driver know that there are no more listeners.
331 d->bd_bif->bif_ifp->if_bpf = 0;
336 * Open ethernet device. Returns ENXIO for illegal minor device number,
337 * EBUSY if file is open by another process.
341 bpfopen(dev, flags, fmt, p)
347 register struct bpf_d *d;
354 * Each minor can be opened by only one process. If the requested
355 * minor is in use, return EBUSY.
359 make_dev(&bpf_cdevsw, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
360 MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK);
361 bzero(d, sizeof(*d));
363 d->bd_bufsize = bpf_bufsize;
370 * Close the descriptor by detaching it from its interface,
371 * deallocating its buffers, and marking it free.
375 bpfclose(dev, flags, fmt, p)
381 register struct bpf_d *d = dev->si_drv1;
384 funsetown(d->bd_sigio);
397 * Support for SunOS, which does not have tsleep.
404 struct bpf_d *d = (struct bpf_d *)arg;
409 #define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan)
413 register struct bpf_d *d;
415 register int rto = d->bd_rtout;
420 timeout(bpf_timeout, (caddr_t)d, rto);
422 st = sleep((caddr_t)d, PRINET|PCATCH);
424 if (d->bd_timedout == 0)
425 untimeout(bpf_timeout, (caddr_t)d);
429 return (st != 0) ? EINTR : 0;
432 #define BPF_SLEEP tsleep
436 * Rotate the packet buffers in descriptor d. Move the store buffer
437 * into the hold slot, and the free buffer into the store slot.
438 * Zero the length of the new store buffer.
440 #define ROTATE_BUFFERS(d) \
441 (d)->bd_hbuf = (d)->bd_sbuf; \
442 (d)->bd_hlen = (d)->bd_slen; \
443 (d)->bd_sbuf = (d)->bd_fbuf; \
447 * bpfread - read next chunk of packets from buffers
450 bpfread(dev, uio, ioflag)
452 register struct uio *uio;
455 register struct bpf_d *d = dev->si_drv1;
460 * Restrict application to use a buffer the same size as
463 if (uio->uio_resid != d->bd_bufsize)
468 * If the hold buffer is empty, then do a timed sleep, which
469 * ends when the timeout expires or when enough packets
470 * have arrived to fill the store buffer.
472 while (d->bd_hbuf == 0) {
473 if (d->bd_immediate && d->bd_slen != 0) {
475 * A packet(s) either arrived since the previous
476 * read or arrived while we were asleep.
477 * Rotate the buffers and return what's here.
482 if (ioflag & IO_NDELAY)
485 error = BPF_SLEEP((caddr_t)d, PRINET|PCATCH, "bpf",
487 if (error == EINTR || error == ERESTART) {
491 if (error == EWOULDBLOCK) {
493 * On a timeout, return what's in the buffer,
494 * which may be nothing. If there is something
495 * in the store buffer, we can rotate the buffers.
499 * We filled up the buffer in between
500 * getting the timeout and arriving
501 * here, so we don't need to rotate.
505 if (d->bd_slen == 0) {
514 * At this point, we know we have something in the hold slot.
519 * Move data from hold buffer into user space.
520 * We know the entire buffer is transferred since
521 * we checked above that the read buffer is bpf_bufsize bytes.
523 error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio);
526 d->bd_fbuf = d->bd_hbuf;
536 * If there are processes sleeping on this descriptor, wake them up.
540 register struct bpf_d *d;
543 if (d->bd_async && d->bd_sig && d->bd_sigio)
544 pgsigio(d->bd_sigio, d->bd_sig, 0);
547 selwakeup(&d->bd_sel);
549 d->bd_sel.si_pid = 0;
552 selwakeup(d->bd_selproc, (int)d->bd_selcoll);
560 bpfwrite(dev, uio, ioflag)
565 register struct bpf_d *d = dev->si_drv1;
569 static struct sockaddr dst;
575 ifp = d->bd_bif->bif_ifp;
577 if (uio->uio_resid == 0)
580 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen);
584 if (datlen > ifp->if_mtu)
589 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0);
591 error = (*ifp->if_output)(ifp, m, &dst);
595 * The driver frees the mbuf.
601 * Reset a descriptor by flushing its packet buffer and clearing the
602 * receive and drop counts. Should be called at splimp.
609 /* Free the hold buffer. */
610 d->bd_fbuf = d->bd_hbuf;
620 * FIONREAD Check for read packet available.
621 * SIOCGIFADDR Get interface address - convenient hook to driver.
622 * BIOCGBLEN Get buffer len [for read()].
623 * BIOCSETF Set ethernet read filter.
624 * BIOCFLUSH Flush read packet buffer.
625 * BIOCPROMISC Put interface into promiscuous mode.
626 * BIOCGDLT Get link layer type.
627 * BIOCGETIF Get interface name.
628 * BIOCSETIF Set interface.
629 * BIOCSRTIMEOUT Set read timeout.
630 * BIOCGRTIMEOUT Get read timeout.
631 * BIOCGSTATS Get packet stats.
632 * BIOCIMMEDIATE Set immediate mode.
633 * BIOCVERSION Get filter language version.
637 bpfioctl(dev, cmd, addr, flags, p)
644 register struct bpf_d *d = dev->si_drv1;
654 * Check for read packet available.
677 ifp = d->bd_bif->bif_ifp;
678 error = (*ifp->if_ioctl)(ifp, cmd, addr);
684 * Get buffer len [for read()].
687 *(u_int *)addr = d->bd_bufsize;
700 register u_int size = *(u_int *)addr;
702 if (size > BPF_MAXBUFSIZE)
703 *(u_int *)addr = size = BPF_MAXBUFSIZE;
704 else if (size < BPF_MINBUFSIZE)
705 *(u_int *)addr = size = BPF_MINBUFSIZE;
706 d->bd_bufsize = size;
712 * Set link layer read filter.
715 error = bpf_setf(d, (struct bpf_program *)addr);
719 * Flush read packet buffer.
728 * Put interface into promiscuous mode.
731 if (d->bd_bif == 0) {
733 * No interface attached yet.
739 if (d->bd_promisc == 0) {
740 error = ifpromisc(d->bd_bif->bif_ifp, 1);
748 * Get device parameters.
754 *(u_int *)addr = d->bd_bif->bif_dlt;
758 * Set interface name.
764 bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr);
771 error = bpf_setif(d, (struct ifreq *)addr);
779 struct timeval *tv = (struct timeval *)addr;
782 * Subtract 1 tick from tvtohz() since this isn't
785 if ((error = itimerfix(tv)) == 0)
786 d->bd_rtout = tvtohz(tv) - 1;
795 struct timeval *tv = (struct timeval *)addr;
797 tv->tv_sec = d->bd_rtout / hz;
798 tv->tv_usec = (d->bd_rtout % hz) * tick;
807 struct bpf_stat *bs = (struct bpf_stat *)addr;
809 bs->bs_recv = d->bd_rcount;
810 bs->bs_drop = d->bd_dcount;
815 * Set immediate mode.
818 d->bd_immediate = *(u_int *)addr;
823 struct bpf_version *bv = (struct bpf_version *)addr;
825 bv->bv_major = BPF_MAJOR_VERSION;
826 bv->bv_minor = BPF_MINOR_VERSION;
830 case FIONBIO: /* Non-blocking I/O */
833 case FIOASYNC: /* Send signal on receive packets */
834 d->bd_async = *(int *)addr;
838 error = fsetown(*(int *)addr, &d->bd_sigio);
842 *(int *)addr = fgetown(d->bd_sigio);
845 /* This is deprecated, FIOSETOWN should be used instead. */
847 error = fsetown(-(*(int *)addr), &d->bd_sigio);
850 /* This is deprecated, FIOGETOWN should be used instead. */
852 *(int *)addr = -fgetown(d->bd_sigio);
855 case BIOCSRSIG: /* Set receive signal */
859 sig = *(u_int *)addr;
868 *(u_int *)addr = d->bd_sig;
875 * Set d's packet filter program to fp. If this file already has a filter,
876 * free it and replace it. Returns EINVAL for bogus requests.
881 struct bpf_program *fp;
883 struct bpf_insn *fcode, *old;
888 if (fp->bf_insns == 0) {
896 free((caddr_t)old, M_BPF);
900 if (flen > BPF_MAXINSNS)
903 size = flen * sizeof(*fp->bf_insns);
904 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK);
905 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 &&
906 bpf_validate(fcode, (int)flen)) {
908 d->bd_filter = fcode;
912 free((caddr_t)old, M_BPF);
916 free((caddr_t)fcode, M_BPF);
921 * Detach a file from its current interface (if attached at all) and attach
922 * to the interface indicated by the name stored in ifr.
923 * Return an errno or 0.
932 struct ifnet *theywant;
934 theywant = ifunit(ifr->ifr_name);
939 * Look through attached interfaces for the named one.
941 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
942 struct ifnet *ifp = bp->bif_ifp;
944 if (ifp == 0 || ifp != theywant)
947 * We found the requested interface.
948 * If it's not up, return an error.
949 * Allocate the packet buffers if we need to.
950 * If we're already attached to requested interface,
951 * just flush the buffer.
953 if ((ifp->if_flags & IFF_UP) == 0)
956 if (d->bd_sbuf == 0) {
957 error = bpf_allocbufs(d);
962 if (bp != d->bd_bif) {
965 * Detach if attached to something else.
980 * Convert an interface name plus unit number of an ifp to a single
981 * name which is returned in the ifr.
988 char *s = ifp->if_name;
989 char *d = ifr->ifr_name;
991 while ((*d++ = *s++) != 0)
993 d--; /* back to the null */
994 /* XXX Assume that unit number is less than 10. */
995 *d++ = ifp->if_unit + '0';
1000 * Support for select() and poll() system calls
1002 * Return true iff the specific operation will not block indefinitely.
1003 * Otherwise, return false but make a note that a selwakeup() must be done.
1006 bpfpoll(dev, events, p)
1011 register struct bpf_d *d;
1016 * An imitation of the FIONREAD ioctl code.
1021 if (events & (POLLIN | POLLRDNORM)) {
1022 if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0))
1023 revents |= events & (POLLIN | POLLRDNORM);
1025 selrecord(p, &d->bd_sel);
1032 * Incoming linkage from device drivers. Process the packet pkt, of length
1033 * pktlen, which is stored in a contiguous buffer. The packet is parsed
1034 * by each process' filter, and if accepted, stashed into the corresponding
1038 bpf_tap(ifp, pkt, pktlen)
1040 register u_char *pkt;
1041 register u_int pktlen;
1044 register struct bpf_d *d;
1045 register u_int slen;
1047 * Note that the ipl does not have to be raised at this point.
1048 * The only problem that could arise here is that if two different
1049 * interfaces shared any data. This is not the case.
1052 for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
1054 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
1056 catchpacket(d, pkt, pktlen, slen, bcopy);
1061 * Copy data from an mbuf chain into a buffer. This code is derived
1062 * from m_copydata in sys/uipc_mbuf.c.
1065 bpf_mcopy(src_arg, dst_arg, len)
1066 const void *src_arg;
1068 register size_t len;
1070 register const struct mbuf *m;
1071 register u_int count;
1079 count = min(m->m_len, len);
1080 bcopy(mtod(m, void *), dst, count);
1088 * Incoming linkage from device drivers, when packet is in an mbuf chain.
1095 struct bpf_if *bp = ifp->if_bpf;
1101 for (m0 = m; m0 != 0; m0 = m0->m_next)
1102 pktlen += m0->m_len;
1104 for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
1106 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0);
1108 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy);
1113 * Move the packet data from interface memory (pkt) into the
1114 * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
1115 * otherwise 0. "copy" is the routine called to do the actual data
1116 * transfer. bcopy is passed in to copy contiguous chunks, while
1117 * bpf_mcopy is passed in to copy mbuf chains. In the latter case,
1118 * pkt is really an mbuf.
1121 catchpacket(d, pkt, pktlen, snaplen, cpfn)
1122 register struct bpf_d *d;
1123 register u_char *pkt;
1124 register u_int pktlen, snaplen;
1125 register void (*cpfn) __P((const void *, void *, size_t));
1127 register struct bpf_hdr *hp;
1128 register int totlen, curlen;
1129 register int hdrlen = d->bd_bif->bif_hdrlen;
1131 * Figure out how many bytes to move. If the packet is
1132 * greater or equal to the snapshot length, transfer that
1133 * much. Otherwise, transfer the whole packet (unless
1134 * we hit the buffer size limit).
1136 totlen = hdrlen + min(snaplen, pktlen);
1137 if (totlen > d->bd_bufsize)
1138 totlen = d->bd_bufsize;
1141 * Round up the end of the previous packet to the next longword.
1143 curlen = BPF_WORDALIGN(d->bd_slen);
1144 if (curlen + totlen > d->bd_bufsize) {
1146 * This packet will overflow the storage buffer.
1147 * Rotate the buffers if we can, then wakeup any
1150 if (d->bd_fbuf == 0) {
1152 * We haven't completed the previous read yet,
1153 * so drop the packet.
1162 else if (d->bd_immediate)
1164 * Immediate mode is set. A packet arrived so any
1165 * reads should be woken up.
1170 * Append the bpf header.
1172 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
1174 microtime(&hp->bh_tstamp);
1176 uniqtime(&hp->bh_tstamp);
1178 hp->bh_tstamp = time;
1180 hp->bh_datalen = pktlen;
1181 hp->bh_hdrlen = hdrlen;
1183 * Copy the packet data into the store buffer and update its length.
1185 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
1186 d->bd_slen = curlen + totlen;
1190 * Initialize all nonzero fields of a descriptor.
1194 register struct bpf_d *d;
1196 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
1197 if (d->bd_fbuf == 0)
1200 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
1201 if (d->bd_sbuf == 0) {
1202 free(d->bd_fbuf, M_BPF);
1211 * Free buffers currently in use by a descriptor.
1216 register struct bpf_d *d;
1219 * We don't need to lock out interrupts since this descriptor has
1220 * been detached from its interface and it yet hasn't been marked
1223 if (d->bd_sbuf != 0) {
1224 free(d->bd_sbuf, M_BPF);
1225 if (d->bd_hbuf != 0)
1226 free(d->bd_hbuf, M_BPF);
1227 if (d->bd_fbuf != 0)
1228 free(d->bd_fbuf, M_BPF);
1231 free((caddr_t)d->bd_filter, M_BPF);
1235 * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *)
1236 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed
1237 * size of the link header (variable length headers not yet supported).
1240 bpfattach(ifp, dlt, hdrlen)
1245 bp = (struct bpf_if *)malloc(sizeof(*bp), M_BPF, M_DONTWAIT);
1253 bp->bif_next = bpf_iflist;
1256 bp->bif_ifp->if_bpf = 0;
1259 * Compute the length of the bpf header. This is not necessarily
1260 * equal to SIZEOF_BPF_HDR because we want to insert spacing such
1261 * that the network layer header begins on a longword boundary (for
1262 * performance reasons and to alleviate alignment restrictions).
1264 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1267 printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);
1270 static void bpf_drvinit __P((void *unused));
1277 cdevsw_add(&bpf_cdevsw);
1280 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
1284 * NOP stubs to allow bpf-using drivers to load and function.
1286 * A 'better' implementation would allow the core bpf functionality
1287 * to be loaded at runtime.
1291 bpf_tap(ifp, pkt, pktlen)
1293 register u_char *pkt;
1294 register u_int pktlen;
1306 bpfattach(ifp, dlt, hdrlen)
1313 bpf_filter(pc, p, wirelen, buflen)
1314 register struct bpf_insn *pc;
1317 register u_int buflen;
1319 return -1; /* "no filter" behaviour */