+/*-
+ * Copyright (c) 1991 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from the Stanford/CMU enet packet filter,
+ * (net/enet.c) distributed as part of 4.3BSD, and code contributed
+ * to Berkeley by Steven McCanne of Lawrence Berkeley Laboratory.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)bpf.c 7.4 (Berkeley) 6/17/91
+ *
+ * static char rcsid[] =
+ * "$Header: /usr/bill/working/sys/net/RCS/bpf.c,v 1.1 92/01/15 20:28:02 william Exp Locker: william $";
+ */
+
+#include "bpfilter.h"
+
+#if (NBPFILTER > 0)
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/mbuf.h>
+#include <sys/buf.h>
+#include <sys/dir.h>
+#include <sys/proc.h>
+#include <sys/user.h>
+#include <sys/ioctl.h>
+
+#include <sys/file.h>
+#ifdef sparc
+#include <sys/stream.h>
+#endif
+#include <sys/tty.h>
+#include <sys/uio.h>
+
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <net/if.h>
+
+#include <net/bpf.h>
+#include <net/bpfdesc.h>
+
+#include <sys/errno.h>
+
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+#include <sys/kernel.h>
+
+#define PRINET 26 /* interruptible */
+
+/*
+ * The default read buffer size is patchable.
+ */
+int bpf_bufsize = MCLBYTES;
+
+/*
+ * bpf_iflist is the list of interfaces; each corresponds to an ifnet
+ * bpf_dtab holds the descriptors, indexed by minor device #
+ *
+ * We really don't need NBPFILTER bpf_if entries, but this eliminates
+ * the need to account for all possible drivers here.
+ * This problem will go away when these structures are allocated dynamically.
+ */
+static struct bpf_if *bpf_iflist;
+static struct bpf_d bpf_dtab[NBPFILTER];
+
+static void bpf_ifname();
+static void catchpacket();
+static int bpf_setif();
+static int bpf_initd();
+
+static int
+bpf_movein(uio, linktype, mp, sockp)
+ register struct uio *uio;
+ int linktype;
+ register struct mbuf **mp;
+ register struct sockaddr *sockp;
+{
+ struct mbuf *m;
+ int error;
+ int len;
+ int hlen;
+
+ /*
+ * Build a sockaddr based on the data link layer type.
+ * We do this at this level because the ethernet header
+ * is copied directly into the data field of the sockaddr.
+ * In the case of SLIP, there is no header and the packet
+ * is forwarded as is.
+ * Also, we are careful to leave room at the front of the mbuf
+ * for the link level header.
+ */
+ switch (linktype) {
+ case DLT_SLIP:
+ sockp->sa_family = AF_INET;
+ hlen = 0;
+ break;
+
+ case DLT_EN10MB:
+ sockp->sa_family = AF_UNSPEC;
+ /* XXX Would MAXLINKHDR be better? */
+ hlen = sizeof(struct ether_header);
+ break;
+
+ case DLT_FDDI:
+ sockp->sa_family = AF_UNSPEC;
+ /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
+ hlen = 24;
+ break;
+
+ default:
+ return (EIO);
+ }
+
+ len = uio->uio_resid;
+ if ((unsigned)len > MCLBYTES)
+ return (EIO);
+
+ MGET(m, M_WAIT, MT_DATA);
+ if (m == 0)
+ return (ENOBUFS);
+ if (len > MLEN) {
+ MCLGET(m, M_WAIT);
+ if ((m->m_flags & M_EXT) == 0) {
+ error = ENOBUFS;
+ goto bad;
+ }
+ }
+ m->m_len = len;
+ *mp = m;
+ /*
+ * Make room for link header.
+ */
+ if (hlen) {
+ m->m_len -= hlen;
+ m->m_data += hlen; /* XXX */
+
+ error = uiomove((caddr_t)sockp->sa_data, hlen, uio);
+ if (error)
+ goto bad;
+ }
+ error = uiomove(mtod(m, caddr_t), len - hlen, uio);
+ if (!error)
+ return (0);
+ bad:
+ m_freem(m);
+ return (error);
+}
+
+/*
+ * Attach 'd' to the bpf interface 'bp', i.e. make 'd' listen on 'bp'.
+ * Must be called at splimp.
+ */
+static void
+bpf_attachd(d, bp)
+ struct bpf_d *d;
+ struct bpf_if *bp;
+{
+ /* Point d at bp. */
+ d->bd_bif = bp;
+
+ /* Add d to bp's list of listeners. */
+ d->bd_next = bp->bif_dlist;
+ bp->bif_dlist = d;
+
+ /*
+ * Let the driver know we're here (if it doesn't already).
+ */
+ *bp->bif_driverp = bp;
+}
+
+static void
+bpf_detachd(d)
+ struct bpf_d *d;
+{
+ struct bpf_d **p;
+ struct bpf_if *bp;
+
+ bp = d->bd_bif;
+ /*
+ * Check if this descriptor had requested promiscuous mode.
+ * If so, turn it off.
+ */
+ if (d->bd_promisc) {
+ d->bd_promisc = 0;
+ if (ifpromisc(bp->bif_ifp, 0))
+ /*
+ * Something is really wrong if we were able to put
+ * the driver into promiscuous mode, but can't
+ * take it out.
+ */
+ panic("bpf_detachd: ifpromisc failed");
+ }
+ /* Remove 'd' from the interface's descriptor list. */
+ p = &bp->bif_dlist;
+ while (*p != d) {
+ p = &(*p)->bd_next;
+ if (*p == 0)
+ panic("bpf_detachd: descriptor not in list");
+ }
+ *p = (*p)->bd_next;
+ if (bp->bif_dlist == 0)
+ /*
+ * Let the driver know that there are no more listeners.
+ */
+ *d->bd_bif->bif_driverp = 0;
+ d->bd_bif = 0;
+}
+
+
+/*
+ * Mark a descriptor free by making it point to itself.
+ * This is probably cheaper than marking with a constant since
+ * the address should be in a register anyway.
+ */
+#define D_ISFREE(d) ((d) == (d)->bd_next)
+#define D_MARKFREE(d) ((d)->bd_next = (d))
+#define D_MARKUSED(d) ((d)->bd_next = 0)
+
+/*
+ * bpfopen - open ethernet device
+ *
+ * Errors: ENXIO - illegal minor device number
+ * EBUSY - too many files open
+ */
+/* ARGSUSED */
+int
+bpfopen(dev, flag)
+ dev_t dev;
+ int flag;
+{
+ int error, s;
+ register struct bpf_d *d;
+
+ if (minor(dev) >= NBPFILTER)
+ return (ENXIO);
+
+ /*
+ * Each minor can be opened by only one process. If the requested
+ * minor is in use, return EBUSY.
+ */
+ s = splimp();
+ d = &bpf_dtab[minor(dev)];
+ if (!D_ISFREE(d)) {
+ splx(s);
+ return (EBUSY);
+ } else
+ /* Mark "free" and do most initialization. */
+ bzero((char *)d, sizeof(*d));
+ splx(s);
+
+ error = bpf_initd(d);
+ if (error) {
+ D_MARKFREE(d);
+ return (error);
+ }
+ return (0);
+}
+
+/*
+ * Close the descriptor by detaching it from its interface,
+ * deallocating its buffers, and marking it free.
+ */
+/* ARGSUSED */
+bpfclose(dev, flag)
+ dev_t dev;
+ int flag;
+{
+ register struct bpf_d *d = &bpf_dtab[minor(dev)];
+ int s;
+
+ s = splimp();
+ if (d->bd_bif)
+ bpf_detachd(d);
+ splx(s);
+
+ /* Free the buffer space. */
+ if (d->bd_hbuf)
+ free(d->bd_hbuf, M_DEVBUF);
+ if (d->bd_fbuf)
+ free(d->bd_fbuf, M_DEVBUF);
+ free(d->bd_sbuf, M_DEVBUF);
+ if (d->bd_filter)
+ free((caddr_t)d->bd_filter, M_DEVBUF);
+
+ D_MARKFREE(d);
+}
+
+/*
+ * Rotate the packet buffers in descriptor d. Move the store buffer
+ * into the hold slot, and the free buffer into the store slot.
+ * Zero the length of the new store buffer.
+ */
+#define ROTATE_BUFFERS(d) \
+ (d)->bd_hbuf = (d)->bd_sbuf; \
+ (d)->bd_hlen = (d)->bd_slen; \
+ (d)->bd_sbuf = (d)->bd_fbuf; \
+ (d)->bd_slen = 0; \
+ (d)->bd_fbuf = 0;
+/*
+ * bpfread - read next chunk of packets from buffers
+ */
+int
+bpfread(dev, uio)
+ dev_t dev;
+ register struct uio *uio;
+{
+ register struct bpf_d *d = &bpf_dtab[minor(dev)];
+ int error;
+ int s;
+
+ /*
+ * Restrict application to use a buffer the same size as
+ * as kernel buffers.
+ */
+ if (uio->uio_resid != d->bd_bufsize)
+ return (EINVAL);
+
+ s = splimp();
+ /*
+ * If the hold buffer is empty, then set a timer and sleep
+ * until either the timeout has occurred or enough packets have
+ * arrived to fill the store buffer.
+ */
+ while (d->bd_hbuf == 0) {
+ if (d->bd_immediate && d->bd_slen != 0) {
+ /*
+ * A packet(s) either arrived since the previous
+ * read or arrived while we were asleep.
+ * Rotate the buffers and return what's here.
+ */
+ ROTATE_BUFFERS(d);
+ break;
+ }
+ error = tsleep((caddr_t)d, PRINET|PCATCH, "bpf", d->bd_rtout);
+ if (error == EINTR || error == ERESTART) {
+ splx(s);
+ return (error);
+ }
+ if (error == EWOULDBLOCK) {
+ /*
+ * On a timeout, return what's in the buffer,
+ * which may be nothing. If there is something
+ * in the store buffer, we can rotate the buffers.
+ */
+ if (d->bd_hbuf)
+ /*
+ * We filled up the buffer in between
+ * getting the timeout and arriving
+ * here, so we don't need to rotate.
+ */
+ break;
+
+ if (d->bd_slen == 0) {
+ splx(s);
+ return (0);
+ }
+ ROTATE_BUFFERS(d);
+ break;
+ }
+ }
+ /*
+ * At this point, we know we have something in the hold slot.
+ */
+ splx(s);
+
+ /*
+ * Move data from hold buffer into user space.
+ * We know the entire buffer is transferred since
+ * we checked above that the read buffer is bpf_bufsize bytes.
+ */
+ error = uiomove(d->bd_hbuf, d->bd_hlen, uio);
+
+ s = splimp();
+ d->bd_fbuf = d->bd_hbuf;
+ d->bd_hbuf = 0;
+ splx(s);
+
+ return (error);
+}
+
+
+/*
+ * If there are processes sleeping on this descriptor, wake them up.
+ */
+static inline void
+bpf_wakeup(d)
+ register struct bpf_d *d;
+{
+ wakeup((caddr_t)d);
+ if (d->bd_selproc) {
+ selwakeup(d->bd_selproc, (int)d->bd_selcoll);
+ d->bd_selcoll = 0;
+ d->bd_selproc = 0;
+ }
+}
+
+int
+bpfwrite(dev, uio)
+ dev_t dev;
+ struct uio *uio;
+{
+ register struct bpf_d *d = &bpf_dtab[minor(dev)];
+ struct ifnet *ifp;
+ struct mbuf *m;
+ int error, s;
+ static struct sockaddr dst;
+
+ if (d->bd_bif == 0)
+ return (ENXIO);
+
+ ifp = d->bd_bif->bif_ifp;
+
+ if (uio->uio_resid == 0)
+ return (0);
+ if (uio->uio_resid > ifp->if_mtu)
+ return (EMSGSIZE);
+
+ error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst);
+ if (error)
+ return (error);
+
+ s = splnet();
+ error = (*ifp->if_output)(ifp, m, &dst);
+ splx(s);
+ /*
+ * The driver frees the mbuf.
+ */
+ return (error);
+}
+
+/*
+ * Reset a descriptor by flushing its packet bufferand clearing the receive
+ * and drop counts. Should be called at splimp.
+ */
+static void
+reset_d(d)
+ struct bpf_d *d;
+{
+ if (d->bd_hbuf) {
+ /* Free the hold buffer. */
+ d->bd_fbuf = d->bd_hbuf;
+ d->bd_hbuf = 0;
+ }
+ d->bd_slen = 0;
+ d->bd_rcount = 0;
+ d->bd_dcount = 0;
+}
+
+/*
+ * FIONREAD Check for read packet available.
+ * SIOCGIFADDR Get interface address - convenient hook to driver.
+ * BIOCGFLEN Get max filter len.
+ * BIOCGBLEN Get buffer len [for read()].
+ * BIOCSETF Set ethernet read filter.
+ * BIOCFLUSH Flush read packet buffer.
+ * BIOCPROMISC Put interface into promiscuous mode.
+ * BIOCGDLT Get link layer type.
+ * BIOCGETIF Get interface name.
+ * BIOCSETIF Set interface.
+ * BIOCSRTIMEOUT Set read timeout.
+ * BIOCGRTIMEOUT Get read timeout.
+ * BIOCGSTATS Get packet stats.
+ * BIOCIMMEDIATE Set immediate mode.
+ */
+/* ARGSUSED */
+int
+bpfioctl(dev, cmd, addr, flag)
+ dev_t dev;
+ int cmd;
+ caddr_t addr;
+ int flag;
+{
+ register struct bpf_d *d = &bpf_dtab[minor(dev)];
+ int s, error = 0;
+
+ switch (cmd) {
+
+ default:
+ error = EINVAL;
+ break;
+
+ /*
+ * Check for read packet available.
+ */
+ case FIONREAD:
+ {
+ int n;
+
+ s = splimp();
+ n = d->bd_slen;
+ if (d->bd_hbuf)
+ n += d->bd_hlen;
+ splx(s);
+
+ *(int *)addr = n;
+ break;
+ }
+
+ case SIOCGIFADDR:
+ {
+ struct ifnet *ifp;
+
+ if (d->bd_bif == 0)
+ error = EINVAL;
+ else {
+ ifp = d->bd_bif->bif_ifp;
+ error = (*ifp->if_ioctl)(ifp, cmd, addr);
+ }
+ break;
+ }
+
+ /*
+ * Get max filter len.
+ */
+ case BIOCGFLEN:
+ *(u_int *)addr = BPF_MAXINSNS;
+ break;
+ /*
+ * Get buffer len [for read()].
+ */
+ case BIOCGBLEN:
+ *(u_int *)addr = d->bd_bufsize;
+ break;
+
+ /*
+ * Set ethernet read filter.
+ */
+ case BIOCSETF:
+ error = bpf_setf(d, (struct bpf_program *)addr);
+ break;
+
+ /*
+ * Flush read packet buffer.
+ */
+ case BIOCFLUSH:
+ s = splimp();
+ reset_d(d);
+ splx(s);
+ break;
+
+ /*
+ * Put interface into promiscuous mode.
+ */
+ case BIOCPROMISC:
+ if (d->bd_bif == 0) {
+ /*
+ * No interface attached yet.
+ */
+ error = EINVAL;
+ break;
+ }
+ s = splimp();
+ if (d->bd_promisc == 0) {
+ d->bd_promisc = 1;
+ error = ifpromisc(d->bd_bif->bif_ifp, 1);
+ }
+ splx(s);
+ break;
+
+ /*
+ * Get device parameters.
+ */
+ case BIOCGDLT:
+ if (d->bd_bif == 0)
+ error = EINVAL;
+ else
+ *(u_int *)addr = d->bd_bif->bif_dlt;
+ break;
+
+ /*
+ * Set interface name.
+ */
+ case BIOCGETIF:
+ if (d->bd_bif == 0)
+ error = EINVAL;
+ else
+ bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr);
+ break;
+
+ /*
+ * Set interface.
+ */
+ case BIOCSETIF:
+ error = bpf_setif(d, (struct ifreq *)addr);
+ break;
+
+ /*
+ * Set read timeout.
+ */
+ case BIOCSRTIMEOUT:
+ {
+ struct timeval *tv = (struct timeval *)addr;
+ u_long msec;
+
+ /* Compute number of milliseconds. */
+ msec = tv->tv_sec * 1000 + tv->tv_usec / 1000;
+ /* Scale milliseconds to ticks. Assume hard
+ clock has millisecond or greater resolution
+ (i.e. tick >= 1000). For 10ms hardclock,
+ tick/1000 = 10, so rtout<-msec/10. */
+ d->bd_rtout = msec / (tick / 1000);
+ break;
+ }
+
+ /*
+ * Get read timeout.
+ */
+ case BIOCGRTIMEOUT:
+ {
+ struct timeval *tv = (struct timeval *)addr;
+ u_long msec = d->bd_rtout;
+
+ msec *= tick / 1000;
+ tv->tv_sec = msec / 1000;
+ tv->tv_usec = msec % 1000;
+ break;
+ }
+
+ /*
+ * Get packet stats.
+ */
+ case BIOCGSTATS:
+ {
+ struct bpf_stat *bs = (struct bpf_stat *)addr;
+
+ bs->bs_recv = d->bd_rcount;
+ bs->bs_drop = d->bd_dcount;
+ break;
+ }
+
+ /*
+ * Set immediate mode.
+ */
+ case BIOCIMMEDIATE:
+ d->bd_immediate = *(u_int *)addr;
+ break;
+ }
+ return (error);
+}
+
+/*
+ * Set d's packet filter program to 'fp'. If 'd' already has a filter,
+ * free it and replace it. Returns EINVAL for bogus requests.
+ */
+int
+bpf_setf(d, fp)
+ struct bpf_d *d;
+ struct bpf_program *fp;
+{
+ struct bpf_insn *fcode, *old;
+ u_int flen, size;
+ int s;
+
+ old = d->bd_filter;
+ if (fp->bf_insns == 0) {
+ if (fp->bf_len != 0)
+ return (EINVAL);
+ s = splimp();
+ d->bd_filter = 0;
+ reset_d(d);
+ splx(s);
+ if (old != 0)
+ free((caddr_t)old, M_DEVBUF);
+ return (0);
+ }
+ flen = fp->bf_len;
+ if (flen > BPF_MAXINSNS)
+ return (EINVAL);
+
+ size = flen * sizeof(*fp->bf_insns);
+ fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK);
+ if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size))
+ return (EINVAL);
+
+ if (bpf_validate(fcode, (int)flen)) {
+ s = splimp();
+ d->bd_filter = fcode;
+ reset_d(d);
+ splx(s);
+ if (old != 0)
+ free((caddr_t)old, M_DEVBUF);
+
+ return (0);
+ }
+ free((caddr_t)fcode, M_DEVBUF);
+ return (EINVAL);
+}
+
+/*
+ * Detach 'd' from its current interface (if attached at all) and attach to
+ * the interface named 'name'. Return ioctl error code or 0.
+ */
+static int
+bpf_setif(d, ifr)
+ struct bpf_d *d;
+ struct ifreq *ifr;
+{
+ struct bpf_if *bp;
+ char *cp;
+ int unit, s;
+
+ /*
+ * Separate string into name part and unit number. Put a null
+ * byte at the end of the name part, and compute the number.
+ * If the a unit number is unspecified, the default is 0,
+ * as initialized above. XXX This should be common code.
+ */
+ unit = 0;
+ cp = ifr->ifr_name;
+ cp[sizeof(ifr->ifr_name) - 1] = '\0';
+ while (*cp++) {
+ if (*cp >= '0' && *cp <= '9') {
+ unit = *cp - '0';
+ *cp++ = '\0';
+ while (*cp)
+ unit = 10 * unit + *cp++ - '0';
+ break;
+ }
+ }
+ /*
+ * Look through attached interfaces for the named one.
+ */
+ for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) {
+ struct ifnet *ifp = bp->bif_ifp;
+
+ if (ifp == 0 || unit != ifp->if_unit
+ || strcmp(ifp->if_name, ifr->ifr_name) != 0)
+ continue;
+ /*
+ * We found the requested interface. If we're
+ * already attached to it, just flush the buffer.
+ * If it's not up, return an error.
+ */
+ if ((ifp->if_flags & IFF_UP) == 0)
+ return (ENETDOWN);
+ s = splimp();
+ if (bp != d->bd_bif) {
+ if (d->bd_bif)
+ /*
+ * Detach if attached to something else.
+ */
+ bpf_detachd(d);
+
+ bpf_attachd(d, bp);
+ }
+ reset_d(d);
+ splx(s);
+ return (0);
+ }
+ /* Not found. */
+ return (ENXIO);
+}
+
+/*
+ * Lookup the name of the 'ifp' interface and return it in 'ifr->ifr_name'.
+ * We augment the ifp's base name with its unit number.
+ */
+static void
+bpf_ifname(ifp, ifr)
+ struct ifnet *ifp;
+ struct ifreq *ifr;
+{
+ char *s = ifp->if_name;
+ char *d = ifr->ifr_name;
+
+ while (*d++ = *s++)
+ ;
+ /* XXX Assume that unit number is less than 10. */
+ *d++ = ifp->if_unit + '0';
+ *d = '\0';
+}
+
+/*
+ * Support for select() system call
+ * Inspired by the code in tty.c for the same purpose.
+ *
+ * bpfselect - returns true iff the specific operation
+ * will not block indefinitely. Otherwise, return
+ * false but make a note that a selwakeup() must be done.
+ */
+int
+bpfselect(dev, rw, p)
+ register dev_t dev;
+ int rw;
+ struct proc *p;
+{
+ register struct bpf_d *d;
+ register int s;
+
+ if (rw != FREAD)
+ return (0);
+ /*
+ * An imitation of the FIONREAD ioctl code.
+ */
+ d = &bpf_dtab[minor(dev)];
+
+ s = splimp();
+ if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) {
+ /*
+ * There is data waiting.
+ */
+ splx(s);
+ return (1);
+ }
+ /*
+ * No data ready. If there's already a select() waiting on this
+ * minor device then this is a collision. This shouldn't happen
+ * because minors really should not be shared, but if a process
+ * forks while one of these is open, it is possible that both
+ * processes could select on the same descriptor.
+ */
+ if (d->bd_selproc && d->bd_selproc->p_wchan == (caddr_t)&selwait)
+ d->bd_selcoll = 1;
+ else
+ d->bd_selproc = p;
+
+ splx(s);
+ return (0);
+}
+
+/*
+ * bpf_tap - incoming linkage from device drivers
+ */
+void
+bpf_tap(arg, pkt, pktlen)
+ caddr_t arg;
+ register u_char *pkt;
+ register u_int pktlen;
+{
+ struct bpf_if *bp;
+ register struct bpf_d *d;
+ register u_int slen;
+ /*
+ * Note that the ipl does not have to be raised at this point.
+ * The only problem that could arise here is that if two different
+ * interfaces shared any data. This is not the case.
+ */
+ bp = (struct bpf_if *)arg;
+ for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
+ ++d->bd_rcount;
+ slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen);
+ if (slen != 0)
+ catchpacket(d, pkt, pktlen, slen, bcopy);
+ }
+}
+
+/*
+ * Copy data from an mbuf chain into a buffer. This code is derived
+ * from m_copydata in sys/uipc_mbuf.c.
+ */
+static void
+bpf_mcopy(src, dst, len)
+ u_char *src;
+ u_char *dst;
+ register int len;
+{
+ register struct mbuf *m = (struct mbuf *)src;
+ register unsigned count;
+
+ while (len > 0) {
+ if (m == 0)
+ panic("bpf_mcopy");
+ count = MIN(m->m_len, len);
+ bcopy(mtod(m, caddr_t), (caddr_t)dst, count);
+ m = m->m_next;
+ dst += count;
+ len -= count;
+ }
+}
+
+/*
+ * bpf_mtap - incoming linkage from device drivers, when packet
+ * is in an mbuf chain
+ */
+void
+bpf_mtap(arg, m)
+ caddr_t arg;
+ struct mbuf *m;
+{
+ struct bpf_if *bp = (struct bpf_if *)arg;
+ struct bpf_d *d;
+ u_int pktlen, slen;
+ struct mbuf *m0;
+
+ pktlen = 0;
+ for (m0 = m; m0 != m; m0 = m0->m_next)
+ pktlen += m0->m_len;
+
+ for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
+ ++d->bd_rcount;
+ slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0);
+ if (slen != 0)
+ catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy);
+ }
+}
+
+/*
+ * Move the packet data from interface memory (pkt) into the
+ * store buffer. Return 1 if it's time to wakeup a listener (buffer full),
+ * otherwise 0. 'copy' is the routine called to do the actual data
+ * transfer. 'bcopy' is passed in to copy contiguous chunks, while
+ * 'bpf_mcopy' is passed in to copy mbuf chains. In the latter
+ * case, 'pkt' is really an mbuf.
+ */
+static void
+catchpacket(d, pkt, pktlen, snaplen, cpfn)
+ register struct bpf_d *d;
+ register u_char *pkt;
+ register u_int pktlen, snaplen;
+ register void (*cpfn)();
+{
+ register struct bpf_hdr *hp;
+ register int totlen, curlen;
+ register int hdrlen = d->bd_bif->bif_hdrlen;
+ /*
+ * Figure out how many bytes to move. If the packet is
+ * greater or equal to the snapshot length, transfer that
+ * much. Otherwise, transfer the whole packet (unless
+ * we hit the buffer size limit).
+ */
+ totlen = hdrlen + MIN(snaplen, pktlen);
+ if (totlen > d->bd_bufsize)
+ totlen = d->bd_bufsize;
+
+ /*
+ * Round up the end of the previous packet to the next longword.
+ */
+ curlen = BPF_WORDALIGN(d->bd_slen);
+ if (curlen + totlen > d->bd_bufsize) {
+ /*
+ * This packet will overflow the storage buffer.
+ * Rotate the buffers if we can, then wakeup any
+ * pending reads.
+ */
+ if (d->bd_fbuf == 0) {
+ /*
+ * We haven't completed the previous read yet,
+ * so drop the packet.
+ */
+ ++d->bd_dcount;
+ return;
+ }
+ ROTATE_BUFFERS(d);
+ bpf_wakeup(d);
+ curlen = 0;
+ }
+ else if (d->bd_immediate)
+ /*
+ * Immediate mode is set. A packet arrived so any
+ * reads should be woken up.
+ */
+ bpf_wakeup(d);
+
+ /*
+ * Append the bpf header.
+ */
+ hp = (struct bpf_hdr *)(d->bd_sbuf + curlen);
+#ifdef sun
+ uniqtime(&hp->bh_tstamp);
+#else
+#ifdef hp300
+ microtime(&hp->bh_tstamp);
+#else
+ hp->bh_tstamp = time;
+#endif
+#endif
+ hp->bh_datalen = pktlen;
+ hp->bh_hdrlen = hdrlen;
+ /*
+ * Copy the packet data into the store buffer and update its length.
+ */
+ (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen));
+ d->bd_slen = curlen + totlen;
+}
+
+/*
+ * Initialize all nonzero fields of a descriptor.
+ */
+static int
+bpf_initd(d)
+ register struct bpf_d *d;
+{
+ d->bd_bufsize = bpf_bufsize;
+ d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK);
+ if (d->bd_fbuf == 0)
+ return (ENOBUFS);
+
+ d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK);
+ if (d->bd_sbuf == 0) {
+ free(d->bd_fbuf, M_DEVBUF);
+ return (ENOBUFS);
+ }
+ d->bd_slen = 0;
+ d->bd_hlen = 0;
+ return (0);
+}
+
+/*
+ * Register 'ifp' with bpf. XXX
+ * and 'driverp' is a pointer to the 'struct bpf_if *' in the driver's softc.
+ */
+void
+bpfattach(driverp, ifp, dlt, hdrlen)
+ caddr_t *driverp;
+ struct ifnet *ifp;
+ u_int dlt, hdrlen;
+{
+ struct bpf_if *bp;
+ int i;
+
+ bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
+ if (bp == 0)
+ panic("bpfattach");
+
+ bp->bif_dlist = 0;
+ bp->bif_driverp = (struct bpf_if **)driverp;
+ bp->bif_ifp = ifp;
+ bp->bif_dlt = dlt;
+
+ bp->bif_next = bpf_iflist;
+ bpf_iflist = bp;
+
+ *bp->bif_driverp = 0;
+
+ /*
+ * Compute the length of the bpf header. This is not necessarily
+ * equal to SIZEOF_BPF_HDR because we want to insert spacing such
+ * that the network layer header begins on a longword boundary (for
+ * performance reasons and to alleviate alignment restrictions).
+ */
+ bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
+
+ /*
+ * Mark all the descriptors free if this hasn't been done.
+ */
+ if (!D_ISFREE(&bpf_dtab[0]))
+ for (i = 0; i < NBPFILTER; ++i)
+ D_MARKFREE(&bpf_dtab[i]);
+
+ printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);
+}
+
+/* XXX This routine belongs in net/if.c. */
+/*
+ * Set/clear promiscuous mode on interface ifp based on the truth value`
+ * of pswitch. The calls are reference counted so that only the first
+ * on request actually has an effect, as does the final off request.
+ * Results are undefined if the off and on requests are not matched.
+ */
+int
+ifpromisc(ifp, pswitch)
+ struct ifnet *ifp;
+ int pswitch;
+{
+ struct ifreq ifr;
+ /*
+ * If the device is not configured up, we cannot put it in
+ * promiscuous mode.
+ */
+ if ((ifp->if_flags & IFF_UP) == 0)
+ return (ENETDOWN);
+
+ if (pswitch) {
+ if (ifp->if_pcount++ != 0)
+ return (0);
+ ifp->if_flags |= IFF_PROMISC;
+ } else {
+ if (--ifp->if_pcount > 0)
+ return (0);
+ ifp->if_flags &= ~IFF_PROMISC;
+ }
+ ifr.ifr_flags = ifp->if_flags;
+ return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr));
+}
+
+#endif (NBPFILTER > 0)
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