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freebsd-skq/sys/net/bpf.c
Peter Wemm c3aac50f28 $Id$ -> $FreeBSD$
1999-08-28 01:08:13 +00:00

1323 lines
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/*
* Copyright (c) 1990, 1991, 1993
* 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 and Van Jacobson both 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 8.2 (Berkeley) 3/28/94
*
* $FreeBSD$
*/
#include "bpf.h"
#ifndef __GNUC__
#define inline
#else
#define inline __inline
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/filedesc.h>
#if defined(sparc) && BSD < 199103
#include <sys/stream.h>
#endif
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/vnode.h>
#include <net/if.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
#if NBPF > 0
/*
* Older BSDs don't have kernel malloc.
*/
#if BSD < 199103
extern bcopy();
static caddr_t bpf_alloc();
#include <net/bpf_compat.h>
#define BPF_BUFSIZE (MCLBYTES-8)
#define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio)
#else
#define BPF_BUFSIZE 4096
#define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio)
#endif
#define PRINET 26 /* interruptible */
/*
* The default read buffer size is patchable.
*/
static int bpf_bufsize = BPF_BUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
&bpf_bufsize, 0, "");
/*
* bpf_iflist is the list of interfaces; each corresponds to an ifnet
*/
static struct bpf_if *bpf_iflist;
static int bpf_allocbufs __P((struct bpf_d *));
static void bpf_attachd __P((struct bpf_d *d, struct bpf_if *bp));
static void bpf_detachd __P((struct bpf_d *d));
static void bpf_freed __P((struct bpf_d *));
static void bpf_ifname __P((struct ifnet *, struct ifreq *));
static void bpf_mcopy __P((const void *, void *, size_t));
static int bpf_movein __P((struct uio *, int,
struct mbuf **, struct sockaddr *, int *));
static int bpf_setif __P((struct bpf_d *, struct ifreq *));
static inline void
bpf_wakeup __P((struct bpf_d *));
static void catchpacket __P((struct bpf_d *, u_char *, u_int,
u_int, void (*)(const void *, void *, size_t)));
static void reset_d __P((struct bpf_d *));
static int bpf_setf __P((struct bpf_d *, struct bpf_program *));
static d_open_t bpfopen;
static d_close_t bpfclose;
static d_read_t bpfread;
static d_write_t bpfwrite;
static d_ioctl_t bpfioctl;
static d_poll_t bpfpoll;
#define CDEV_MAJOR 23
static struct cdevsw bpf_cdevsw = {
/* open */ bpfopen,
/* close */ bpfclose,
/* read */ bpfread,
/* write */ bpfwrite,
/* ioctl */ bpfioctl,
/* stop */ nostop,
/* reset */ noreset,
/* devtotty */ nodevtotty,
/* poll */ bpfpoll,
/* mmap */ nommap,
/* strategy */ nostrategy,
/* name */ "bpf",
/* parms */ noparms,
/* maj */ CDEV_MAJOR,
/* dump */ nodump,
/* psize */ nopsize,
/* flags */ 0,
/* maxio */ 0,
/* bmaj */ -1
};
static int
bpf_movein(uio, linktype, mp, sockp, datlen)
register struct uio *uio;
int linktype, *datlen;
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:
#if defined(__FreeBSD__) || defined(__bsdi__)
sockp->sa_family = AF_IMPLINK;
hlen = 0;
#else
sockp->sa_family = AF_UNSPEC;
/* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
hlen = 24;
#endif
break;
case DLT_RAW:
case DLT_NULL:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
break;
#ifdef __FreeBSD__
case DLT_ATM_RFC1483:
/*
* en atm driver requires 4-byte atm pseudo header.
* though it isn't standard, vpi:vci needs to be
* specified anyway.
*/
sockp->sa_family = AF_UNSPEC;
hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */
break;
#endif
default:
return (EIO);
}
len = uio->uio_resid;
*datlen = len - hlen;
if ((unsigned)len > MCLBYTES)
return (EIO);
MGETHDR(m, M_WAIT, MT_DATA);
if (m == 0)
return (ENOBUFS);
if (len > MHLEN) {
#if BSD >= 199103
MCLGET(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0) {
#else
MCLGET(m);
if (m->m_len != MCLBYTES) {
#endif
error = ENOBUFS;
goto bad;
}
}
m->m_pkthdr.len = m->m_len = len;
m->m_pkthdr.rcvif = NULL;
*mp = m;
/*
* Make room for link header.
*/
if (hlen != 0) {
m->m_pkthdr.len -= hlen;
m->m_len -= hlen;
#if BSD >= 199103
m->m_data += hlen; /* XXX */
#else
m->m_off += hlen;
#endif
error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio);
if (error)
goto bad;
}
error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio);
if (!error)
return (0);
bad:
m_freem(m);
return (error);
}
/*
* Attach file to the bpf interface, 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, and add d to the interface's list of listeners.
* Finally, point the driver's bpf cookie at the interface so
* it will divert packets to bpf.
*/
d->bd_bif = bp;
d->bd_next = bp->bif_dlist;
bp->bif_dlist = d;
bp->bif_ifp->if_bpf = bp;
}
/*
* Detach a file from its interface.
*/
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: 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_ifp->if_bpf = 0;
d->bd_bif = 0;
}
/*
* Open ethernet device. Returns ENXIO for illegal minor device number,
* EBUSY if file is open by another process.
*/
/* ARGSUSED */
static int
bpfopen(dev, flags, fmt, p)
dev_t dev;
int flags;
int fmt;
struct proc *p;
{
register struct bpf_d *d;
if (p->p_prison)
return (EPERM);
d = dev->si_drv1;
/*
* Each minor can be opened by only one process. If the requested
* minor is in use, return EBUSY.
*/
if (d)
return (EBUSY);
make_dev(&bpf_cdevsw, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev));
MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK);
bzero(d, sizeof(*d));
dev->si_drv1 = d;
d->bd_bufsize = bpf_bufsize;
d->bd_sig = SIGIO;
return (0);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
static int
bpfclose(dev, flags, fmt, p)
dev_t dev;
int flags;
int fmt;
struct proc *p;
{
register struct bpf_d *d = dev->si_drv1;
register int s;
funsetown(d->bd_sigio);
s = splimp();
if (d->bd_bif)
bpf_detachd(d);
splx(s);
bpf_freed(d);
dev->si_drv1 = 0;
FREE(d, M_BPF);
return (0);
}
/*
* Support for SunOS, which does not have tsleep.
*/
#if BSD < 199103
static
bpf_timeout(arg)
caddr_t arg;
{
struct bpf_d *d = (struct bpf_d *)arg;
d->bd_timedout = 1;
wakeup(arg);
}
#define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan)
int
bpf_sleep(d)
register struct bpf_d *d;
{
register int rto = d->bd_rtout;
register int st;
if (rto != 0) {
d->bd_timedout = 0;
timeout(bpf_timeout, (caddr_t)d, rto);
}
st = sleep((caddr_t)d, PRINET|PCATCH);
if (rto != 0) {
if (d->bd_timedout == 0)
untimeout(bpf_timeout, (caddr_t)d);
else if (st == 0)
return EWOULDBLOCK;
}
return (st != 0) ? EINTR : 0;
}
#else
#define BPF_SLEEP tsleep
#endif
/*
* 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
*/
static int
bpfread(dev, uio, ioflag)
dev_t dev;
register struct uio *uio;
int ioflag;
{
register struct bpf_d *d = dev->si_drv1;
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 do a timed sleep, which
* ends when the timeout expires or when 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;
}
if (ioflag & IO_NDELAY)
error = EWOULDBLOCK;
else
error = BPF_SLEEP((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_READ, uio);
s = splimp();
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = 0;
d->bd_hlen = 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_async && d->bd_sig && d->bd_sigio)
pgsigio(d->bd_sigio, d->bd_sig, 0);
#if BSD >= 199103
selwakeup(&d->bd_sel);
/* XXX */
d->bd_sel.si_pid = 0;
#else
if (d->bd_selproc) {
selwakeup(d->bd_selproc, (int)d->bd_selcoll);
d->bd_selcoll = 0;
d->bd_selproc = 0;
}
#endif
}
static int
bpfwrite(dev, uio, ioflag)
dev_t dev;
struct uio *uio;
int ioflag;
{
register struct bpf_d *d = dev->si_drv1;
struct ifnet *ifp;
struct mbuf *m;
int error, s;
static struct sockaddr dst;
int datlen;
if (d->bd_bif == 0)
return (ENXIO);
ifp = d->bd_bif->bif_ifp;
if (uio->uio_resid == 0)
return (0);
error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen);
if (error)
return (error);
if (datlen > ifp->if_mtu)
return (EMSGSIZE);
s = splnet();
#if BSD >= 199103
error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0);
#else
error = (*ifp->if_output)(ifp, m, &dst);
#endif
splx(s);
/*
* The driver frees the mbuf.
*/
return (error);
}
/*
* Reset a descriptor by flushing its packet buffer and 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_hlen = 0;
d->bd_rcount = 0;
d->bd_dcount = 0;
}
/*
* FIONREAD Check for read packet available.
* SIOCGIFADDR Get interface address - convenient hook to driver.
* 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.
* BIOCVERSION Get filter language version.
*/
/* ARGSUSED */
static int
bpfioctl(dev, cmd, addr, flags, p)
dev_t dev;
u_long cmd;
caddr_t addr;
int flags;
struct proc *p;
{
register struct bpf_d *d = dev->si_drv1;
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 buffer len [for read()].
*/
case BIOCGBLEN:
*(u_int *)addr = d->bd_bufsize;
break;
/*
* Set buffer length.
*/
case BIOCSBLEN:
#if BSD < 199103
error = EINVAL;
#else
if (d->bd_bif != 0)
error = EINVAL;
else {
register u_int size = *(u_int *)addr;
if (size > BPF_MAXBUFSIZE)
*(u_int *)addr = size = BPF_MAXBUFSIZE;
else if (size < BPF_MINBUFSIZE)
*(u_int *)addr = size = BPF_MINBUFSIZE;
d->bd_bufsize = size;
}
#endif
break;
/*
* Set link layer 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) {
error = ifpromisc(d->bd_bif->bif_ifp, 1);
if (error == 0)
d->bd_promisc = 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;
/*
* Subtract 1 tick from tvtohz() since this isn't
* a one-shot timer.
*/
if ((error = itimerfix(tv)) == 0)
d->bd_rtout = tvtohz(tv) - 1;
break;
}
/*
* Get read timeout.
*/
case BIOCGRTIMEOUT:
{
struct timeval *tv = (struct timeval *)addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
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;
case BIOCVERSION:
{
struct bpf_version *bv = (struct bpf_version *)addr;
bv->bv_major = BPF_MAJOR_VERSION;
bv->bv_minor = BPF_MINOR_VERSION;
break;
}
case FIONBIO: /* Non-blocking I/O */
break;
case FIOASYNC: /* Send signal on receive packets */
d->bd_async = *(int *)addr;
break;
case FIOSETOWN:
error = fsetown(*(int *)addr, &d->bd_sigio);
break;
case FIOGETOWN:
*(int *)addr = fgetown(d->bd_sigio);
break;
/* This is deprecated, FIOSETOWN should be used instead. */
case TIOCSPGRP:
error = fsetown(-(*(int *)addr), &d->bd_sigio);
break;
/* This is deprecated, FIOGETOWN should be used instead. */
case TIOCGPGRP:
*(int *)addr = -fgetown(d->bd_sigio);
break;
case BIOCSRSIG: /* Set receive signal */
{
u_int sig;
sig = *(u_int *)addr;
if (sig >= NSIG)
error = EINVAL;
else
d->bd_sig = sig;
break;
}
case BIOCGRSIG:
*(u_int *)addr = d->bd_sig;
break;
}
return (error);
}
/*
* Set d's packet filter program to fp. If this file already has a filter,
* free it and replace it. Returns EINVAL for bogus requests.
*/
static 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_BPF);
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_BPF, M_WAITOK);
if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 &&
bpf_validate(fcode, (int)flen)) {
s = splimp();
d->bd_filter = fcode;
reset_d(d);
splx(s);
if (old != 0)
free((caddr_t)old, M_BPF);
return (0);
}
free((caddr_t)fcode, M_BPF);
return (EINVAL);
}
/*
* Detach a file from its current interface (if attached at all) and attach
* to the interface indicated by the name stored in ifr.
* Return an errno or 0.
*/
static int
bpf_setif(d, ifr)
struct bpf_d *d;
struct ifreq *ifr;
{
struct bpf_if *bp;
int s, error;
struct ifnet *theywant;
theywant = ifunit(ifr->ifr_name);
if (theywant == 0)
return ENXIO;
/*
* 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 || ifp != theywant)
continue;
/*
* We found the requested interface.
* If it's not up, return an error.
* Allocate the packet buffers if we need to.
* If we're already attached to requested interface,
* just flush the buffer.
*/
if ((ifp->if_flags & IFF_UP) == 0)
return (ENETDOWN);
if (d->bd_sbuf == 0) {
error = bpf_allocbufs(d);
if (error != 0)
return (error);
}
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);
}
/*
* Convert an interface name plus unit number of an ifp to a single
* name which is returned in the ifr.
*/
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++) != 0)
continue;
d--; /* back to the null */
/* XXX Assume that unit number is less than 10. */
*d++ = ifp->if_unit + '0';
*d = '\0';
}
/*
* Support for select() and poll() system calls
*
* Return true iff the specific operation will not block indefinitely.
* Otherwise, return false but make a note that a selwakeup() must be done.
*/
int
bpfpoll(dev, events, p)
register dev_t dev;
int events;
struct proc *p;
{
register struct bpf_d *d;
register int s;
int revents = 0;
/*
* An imitation of the FIONREAD ioctl code.
*/
d = dev->si_drv1;
s = splimp();
if (events & (POLLIN | POLLRDNORM)) {
if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0))
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(p, &d->bd_sel);
}
splx(s);
return (revents);
}
/*
* Incoming linkage from device drivers. Process the packet pkt, of length
* pktlen, which is stored in a contiguous buffer. The packet is parsed
* by each process' filter, and if accepted, stashed into the corresponding
* buffer.
*/
void
bpf_tap(ifp, pkt, pktlen)
struct ifnet *ifp;
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 = ifp->if_bpf;
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_arg, dst_arg, len)
const void *src_arg;
void *dst_arg;
register size_t len;
{
register const struct mbuf *m;
register u_int count;
u_char *dst;
m = src_arg;
dst = dst_arg;
while (len > 0) {
if (m == 0)
panic("bpf_mcopy");
count = min(m->m_len, len);
bcopy(mtod(m, void *), dst, count);
m = m->m_next;
dst += count;
len -= count;
}
}
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
*/
void
bpf_mtap(ifp, m)
struct ifnet *ifp;
struct mbuf *m;
{
struct bpf_if *bp = ifp->if_bpf;
struct bpf_d *d;
u_int pktlen, slen;
struct mbuf *m0;
pktlen = 0;
for (m0 = m; m0 != 0; 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) __P((const void *, void *, size_t));
{
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);
#if BSD >= 199103
microtime(&hp->bh_tstamp);
#elif defined(sun)
uniqtime(&hp->bh_tstamp);
#else
hp->bh_tstamp = time;
#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_allocbufs(d)
register struct bpf_d *d;
{
d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
if (d->bd_fbuf == 0)
return (ENOBUFS);
d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
if (d->bd_sbuf == 0) {
free(d->bd_fbuf, M_BPF);
return (ENOBUFS);
}
d->bd_slen = 0;
d->bd_hlen = 0;
return (0);
}
/*
* Free buffers currently in use by a descriptor.
* Called on close.
*/
static void
bpf_freed(d)
register struct bpf_d *d;
{
/*
* We don't need to lock out interrupts since this descriptor has
* been detached from its interface and it yet hasn't been marked
* free.
*/
if (d->bd_sbuf != 0) {
free(d->bd_sbuf, M_BPF);
if (d->bd_hbuf != 0)
free(d->bd_hbuf, M_BPF);
if (d->bd_fbuf != 0)
free(d->bd_fbuf, M_BPF);
}
if (d->bd_filter)
free((caddr_t)d->bd_filter, M_BPF);
}
/*
* Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *)
* in the driver's softc; dlt is the link layer type; hdrlen is the fixed
* size of the link header (variable length headers not yet supported).
*/
void
bpfattach(ifp, dlt, hdrlen)
struct ifnet *ifp;
u_int dlt, hdrlen;
{
struct bpf_if *bp;
bp = (struct bpf_if *)malloc(sizeof(*bp), M_BPF, M_DONTWAIT);
if (bp == 0)
panic("bpfattach");
bp->bif_dlist = 0;
bp->bif_ifp = ifp;
bp->bif_dlt = dlt;
bp->bif_next = bpf_iflist;
bpf_iflist = bp;
bp->bif_ifp->if_bpf = 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;
if (bootverbose)
printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit);
}
static void bpf_drvinit __P((void *unused));
static void
bpf_drvinit(unused)
void *unused;
{
cdevsw_add(&bpf_cdevsw);
}
SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL)
#else /* !BPF */
/*
* NOP stubs to allow bpf-using drivers to load and function.
*
* A 'better' implementation would allow the core bpf functionality
* to be loaded at runtime.
*/
void
bpf_tap(ifp, pkt, pktlen)
struct ifnet *ifp;
register u_char *pkt;
register u_int pktlen;
{
}
void
bpf_mtap(ifp, m)
struct ifnet *ifp;
struct mbuf *m;
{
}
void
bpfattach(ifp, dlt, hdrlen)
struct ifnet *ifp;
u_int dlt, hdrlen;
{
}
u_int
bpf_filter(pc, p, wirelen, buflen)
register struct bpf_insn *pc;
register u_char *p;
u_int wirelen;
register u_int buflen;
{
return -1; /* "no filter" behaviour */
}
#endif /* !BPF */
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