NetBSD/sys/net/bpf.c

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2001-11-13 02:49:33 +03:00
/* $NetBSD: bpf.c,v 1.63 2001/11/12 23:49:33 lukem Exp $ */
/*
* Copyright (c) 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
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*
* 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.
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*
* 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.
*
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* @(#)bpf.c 8.4 (Berkeley) 1/9/95
* static char rcsid[] =
* "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp ";
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*/
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#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.63 2001/11/12 23:49:33 lukem Exp $");
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#include "bpfilter.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/buf.h>
#include <sys/time.h>
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#include <sys/proc.h>
#include <sys/user.h>
#include <sys/ioctl.h>
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#include <sys/map.h>
#include <sys/conf.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
#include <sys/tty.h>
#include <sys/uio.h>
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#include <sys/protosw.h>
#include <sys/socket.h>
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#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/poll.h>
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#include <net/if.h>
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#include <net/bpf.h>
#include <net/bpfdesc.h>
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#include <net/if_arc.h>
#include <net/if_ether.h>
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#ifndef BPF_BUFSIZE
# define BPF_BUFSIZE 8192 /* 4096 too small for FDDI frames */
#endif
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#define PRINET 26 /* interruptible */
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/*
* The default read buffer size is patchable.
*/
int bpf_bufsize = BPF_BUFSIZE;
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/*
* bpf_iflist is the list of interfaces; each corresponds to an ifnet
* bpf_dtab holds the descriptors, indexed by minor device #
*/
struct bpf_if *bpf_iflist;
struct bpf_d bpf_dtab[NBPFILTER];
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static int bpf_allocbufs __P((struct bpf_d *));
static void bpf_freed __P((struct bpf_d *));
static void bpf_ifname __P((struct ifnet *, struct ifreq *));
static void *bpf_mcpy __P((void *, const void *, size_t));
static int bpf_movein __P((struct uio *, int, int,
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struct mbuf **, struct sockaddr *));
static void bpf_attachd __P((struct bpf_d *, struct bpf_if *));
static void bpf_detachd __P((struct bpf_d *));
static int bpf_setif __P((struct bpf_d *, struct ifreq *));
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int bpfpoll __P((dev_t, int, struct proc *));
static __inline void
bpf_wakeup __P((struct bpf_d *));
static void catchpacket __P((struct bpf_d *, u_char *, u_int, u_int,
void *(*)(void *, const void *, size_t)));
static void reset_d __P((struct bpf_d *));
static int
bpf_movein(uio, linktype, mtu, mp, sockp)
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struct uio *uio;
int linktype;
int mtu;
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struct mbuf **mp;
struct sockaddr *sockp;
{
struct mbuf *m;
int error;
int len;
int hlen;
int align;
/*
* 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;
align = 0;
break;
case DLT_PPP:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
align = 0;
break;
case DLT_EN10MB:
sockp->sa_family = AF_UNSPEC;
/* XXX Would MAXLINKHDR be better? */
/* 6(dst)+6(src)+2(type) */
hlen = sizeof(struct ether_header);
align = 2;
break;
case DLT_ARCNET:
sockp->sa_family = AF_UNSPEC;
hlen = ARC_HDRLEN;
align = 5;
break;
case DLT_FDDI:
sockp->sa_family = AF_LINK;
/* XXX 4(FORMAC)+6(dst)+6(src) */
hlen = 16;
align = 0;
break;
case DLT_ECONET:
sockp->sa_family = AF_UNSPEC;
hlen = 6;
align = 2;
break;
case DLT_NULL:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
align = 0;
break;
default:
return (EIO);
}
len = uio->uio_resid;
/*
* If there aren't enough bytes for a link level header or the
* packet length exceeds the interface mtu, return an error.
*/
if (len < hlen || len - hlen > mtu)
return (EMSGSIZE);
/*
* XXX Avoid complicated buffer chaining ---
* bail if it won't fit in a single mbuf.
* (Take into account possible alignment bytes)
*/
if ((unsigned)len > MCLBYTES - align)
return (EIO);
MGETHDR(m, M_WAIT, MT_DATA);
if (m == 0)
return (ENOBUFS);
m->m_pkthdr.rcvif = 0;
m->m_pkthdr.len = len - hlen;
if (len > MHLEN - align) {
MCLGET(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0) {
error = ENOBUFS;
goto bad;
}
}
/* Insure the data is properly aligned */
if (align > 0) {
m->m_data += align;
m->m_len -= align;
}
error = uiomove(mtod(m, caddr_t), len, uio);
if (error)
goto bad;
if (hlen != 0) {
memcpy(sockp->sa_data, mtod(m, caddr_t), hlen);
m->m_data += hlen; /* XXX */
len -= hlen;
}
m->m_len = len;
*mp = m;
return (0);
bad:
m_freem(m);
return (error);
}
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/*
* Attach file to the bpf interface, i.e. make d listen on bp.
* Must be called at splnet.
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*/
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.
*/
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d->bd_bif = bp;
d->bd_next = bp->bif_dlist;
bp->bif_dlist = d;
*bp->bif_driverp = bp;
}
/*
* Detach a file from its interface.
*/
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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) {
int error;
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d->bd_promisc = 0;
/*
* Take device out of promiscuous mode. Since we were
* able to enter promiscuous mode, we should be able
* to turn it off. But we can get an error if
* the interface was configured down, so only panic
* if we don't get an unexpected error.
*/
error = ifpromisc(bp->bif_ifp, 0);
if (error && error != EINVAL)
panic("bpf: ifpromisc failed");
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}
/* Remove d from the interface's descriptor list. */
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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.
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* 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)
/*
* bpfilterattach() is called at boot time.
*/
/* ARGSUSED */
void
bpfilterattach(n)
int n;
{
int i;
/*
* Mark all the descriptors free.
*/
for (i = 0; i < NBPFILTER; ++i)
D_MARKFREE(&bpf_dtab[i]);
}
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/*
* Open ethernet device. Returns ENXIO for illegal minor device number,
* EBUSY if file is open by another process.
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*/
/* ARGSUSED */
int
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bpfopen(dev, flag, mode, p)
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dev_t dev;
int flag;
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int mode;
struct proc *p;
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{
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struct bpf_d *d;
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if (minor(dev) >= NBPFILTER)
return (ENXIO);
/*
* Each minor can be opened by only one process. If the requested
* minor is in use, return EBUSY.
*/
d = &bpf_dtab[minor(dev)];
if (!D_ISFREE(d))
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return (EBUSY);
/* Mark "free" and do most initialization. */
memset((char *)d, 0, sizeof(*d));
d->bd_bufsize = bpf_bufsize;
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return (0);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
int
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bpfclose(dev, flag, mode, p)
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dev_t dev;
int flag;
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int mode;
struct proc *p;
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{
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struct bpf_d *d = &bpf_dtab[minor(dev)];
int s;
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s = splnet();
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if (d->bd_bif)
bpf_detachd(d);
splx(s);
bpf_freed(d);
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return (0);
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}
/*
* Rotate the packet buffers in descriptor d. Move the store buffer
* into the hold slot, and the free buffer into the store slot.
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* 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;
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/*
* bpfread - read next chunk of packets from buffers
*/
int
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bpfread(dev, uio, ioflag)
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dev_t dev;
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struct uio *uio;
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int ioflag;
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{
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struct bpf_d *d = &bpf_dtab[minor(dev)];
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int error;
int s;
/*
* Restrict application to use a buffer the same size as
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* as kernel buffers.
*/
if (uio->uio_resid != d->bd_bufsize)
return (EINVAL);
s = splnet();
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/*
* 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.
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*/
while (d->bd_hbuf == 0) {
if (d->bd_immediate) {
if (d->bd_slen == 0) {
splx(s);
return (EWOULDBLOCK);
}
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/*
* 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 (d->bd_rtout != -1)
error = tsleep((caddr_t)d, PRINET|PCATCH, "bpf",
d->bd_rtout);
else {
if (d->bd_rtout == -1) {
/* User requested non-blocking I/O */
error = EWOULDBLOCK;
} else
error = 0;
}
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)
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/*
* We filled up the buffer in between
* getting the timeout and arriving
* here, so we don't need to rotate.
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*/
break;
if (d->bd_slen == 0) {
splx(s);
return (0);
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}
ROTATE_BUFFERS(d);
break;
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}
if (error != 0)
goto done;
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}
/*
* At this point, we know we have something in the hold slot.
*/
splx(s);
/*
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* 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);
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s = splnet();
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d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = 0;
d->bd_hlen = 0;
done:
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splx(s);
return (error);
}
/*
* If there are processes sleeping on this descriptor, wake them up.
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*/
static __inline void
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bpf_wakeup(d)
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struct bpf_d *d;
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{
struct proc *p;
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wakeup((caddr_t)d);
if (d->bd_async) {
if (d->bd_pgid > 0)
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gsignal (d->bd_pgid, SIGIO);
else if (d->bd_pgid && (p = pfind (-d->bd_pgid)) != NULL)
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psignal (p, SIGIO);
}
selwakeup(&d->bd_sel);
/* XXX */
d->bd_sel.si_pid = 0;
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}
int
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bpfwrite(dev, uio, ioflag)
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dev_t dev;
struct uio *uio;
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int ioflag;
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{
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struct bpf_d *d = &bpf_dtab[minor(dev)];
struct ifnet *ifp;
struct mbuf *m;
int error, s;
static struct sockaddr_storage dst;
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if (d->bd_bif == 0)
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return (ENXIO);
ifp = d->bd_bif->bif_ifp;
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if (uio->uio_resid == 0)
return (0);
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error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, &m,
(struct sockaddr *) &dst);
if (error)
return (error);
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if (m->m_pkthdr.len > ifp->if_mtu)
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return (EMSGSIZE);
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if (d->bd_hdrcmplt)
dst.ss_family = pseudo_AF_HDRCMPLT;
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s = splsoftnet();
error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL);
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splx(s);
/*
* The driver frees the mbuf.
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*/
return (error);
}
/*
* Reset a descriptor by flushing its packet buffer and clearing the
* receive and drop counts. Should be called at splnet.
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*/
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;
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d->bd_rcount = 0;
d->bd_dcount = 0;
}
#ifdef BPF_KERN_FILTER
extern struct bpf_insn *bpf_tcp_filter;
extern struct bpf_insn *bpf_udp_filter;
#endif
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/*
* FIONREAD Check for read packet available.
* 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.
* BIOGHDRCMPLT Get "header already complete" flag.
* BIOSHDRCMPLT Set "header already complete" flag.
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*/
/* ARGSUSED */
int
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bpfioctl(dev, cmd, addr, flag, p)
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dev_t dev;
u_long cmd;
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caddr_t addr;
int flag;
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struct proc *p;
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{
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struct bpf_d *d = &bpf_dtab[minor(dev)];
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int s, error = 0;
#ifdef BPF_KERN_FILTER
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struct bpf_insn **p;
#endif
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switch (cmd) {
default:
error = EINVAL;
break;
/*
* Check for read packet available.
*/
case FIONREAD:
{
int n;
s = splnet();
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n = d->bd_slen;
if (d->bd_hbuf)
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n += d->bd_hlen;
splx(s);
*(int *)addr = n;
break;
}
/*
* Get buffer len [for read()].
*/
case BIOCGBLEN:
*(u_int *)addr = d->bd_bufsize;
break;
/*
* Set buffer length.
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*/
case BIOCSBLEN:
if (d->bd_bif != 0)
error = EINVAL;
else {
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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;
}
break;
/*
* Set link layer read filter.
*/
case BIOCSETF:
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error = bpf_setf(d, (struct bpf_program *)addr);
break;
#ifdef BPF_KERN_FILTER
/*
* Set TCP or UDP reject filter.
*/
case BIOCSTCPF:
case BIOCSUDPF:
if (!suser()) {
error = EPERM;
break;
}
/* Validate and store filter */
error = bpf_setf(d, (struct bpf_program *)addr);
/* Free possible old filter */
if (cmd == BIOCSTCPF)
p = &bpf_tcp_filter;
else
p = &bpf_udp_filter;
if (*p != NULL)
free((caddr_t)*p, M_DEVBUF);
/* Steal new filter (noop if error) */
s = splnet();
*p = d->bd_filter;
d->bd_filter = NULL;
splx(s);
break;
#endif
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/*
* Flush read packet buffer.
*/
case BIOCFLUSH:
s = splnet();
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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 = splnet();
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if (d->bd_promisc == 0) {
error = ifpromisc(d->bd_bif->bif_ifp, 1);
if (error == 0)
d->bd_promisc = 1;
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}
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:
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{
struct timeval *tv = (struct timeval *)addr;
/* Compute number of ticks. */
d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick;
if ((d->bd_rtout == 0) && (tv->tv_usec != 0))
d->bd_rtout = 1;
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break;
}
/*
* Get read timeout.
*/
case BIOCGRTIMEOUT:
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{
struct timeval *tv = (struct timeval *)addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
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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 BIOCGHDRCMPLT: /* get "header already complete" flag */
*(u_int *)addr = d->bd_hdrcmplt;
break;
case BIOCSHDRCMPLT: /* set "header already complete" flag */
d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
break;
case FIONBIO: /* Non-blocking I/O */
if (*(int *)addr)
d->bd_rtout = -1;
else
d->bd_rtout = 0;
break;
case FIOASYNC: /* Send signal on receive packets */
d->bd_async = *(int *)addr;
break;
/*
* N.B. ioctl (FIOSETOWN) and fcntl (F_SETOWN) both end up doing
* the equivalent of a TIOCSPGRP and hence end up here. *However*
* TIOCSPGRP's arg is a process group if it's positive and a process
* id if it's negative. This is exactly the opposite of what the
* other two functions want! Therefore there is code in ioctl and
* fcntl to negate the arg before calling here.
*/
case TIOCSPGRP: /* Process or group to send signals to */
d->bd_pgid = *(int *)addr;
break;
case TIOCGPGRP:
*(int *)addr = d->bd_pgid;
break;
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}
return (error);
}
/*
* Set d's packet filter program to fp. If this file already has a filter,
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* 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 = splnet();
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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) == 0 &&
bpf_validate(fcode, (int)flen)) {
s = splnet();
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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 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.
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*/
static int
bpf_setif(d, ifr)
struct bpf_d *d;
struct ifreq *ifr;
{
struct bpf_if *bp;
char *cp;
int unit_seen, i, s, error;
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/*
* Make sure the provided name has a unit number, and default
* it to '0' if not specified.
* XXX This is ugly ... do this differently?
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*/
unit_seen = 0;
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cp = ifr->ifr_name;
cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */
while (*cp++)
if (*cp >= '0' && *cp <= '9')
unit_seen = 1;
if (!unit_seen) {
/* Make sure to leave room for the '\0'. */
for (i = 0; i < (IFNAMSIZ - 1); ++i) {
if ((ifr->ifr_name[i] >= 'a' &&
ifr->ifr_name[i] <= 'z') ||
(ifr->ifr_name[i] >= 'A' &&
ifr->ifr_name[i] <= 'Z'))
continue;
ifr->ifr_name[i] = '0';
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}
}
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/*
* 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 ||
strcmp(ifp->if_xname, ifr->ifr_name) != 0)
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continue;
/*
* We found the requested interface.
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* 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.
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*/
if ((ifp->if_flags & IFF_UP) == 0)
return (ENETDOWN);
if (d->bd_sbuf == 0) {
error = bpf_allocbufs(d);
if (error != 0)
return (error);
}
s = splnet();
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if (bp != d->bd_bif) {
if (d->bd_bif)
/*
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* Detach if attached to something else.
*/
bpf_detachd(d);
bpf_attachd(d, bp);
}
reset_d(d);
splx(s);
return (0);
}
/* Not found. */
return (ENXIO);
}
/*
* Copy the interface name to the ifreq.
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*/
static void
bpf_ifname(ifp, ifr)
struct ifnet *ifp;
struct ifreq *ifr;
{
memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
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}
/*
* Support for poll() system call
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*
* Return true iff the specific operation will not block indefinitely.
* Otherwise, return false but make a note that a selwakeup() must be done.
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*/
int
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bpfpoll(dev, events, p)
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dev_t dev;
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int events;
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struct proc *p;
{
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struct bpf_d *d = &bpf_dtab[minor(dev)];
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int revents = 0;
int s = splnet();
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/*
* An imitation of the FIONREAD ioctl code.
*/
if (events & (POLLIN | POLLRDNORM)) {
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if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0))
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(p, &d->bd_sel);
}
splx(s);
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return (revents);
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}
/*
* 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.
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*/
void
bpf_tap(arg, pkt, pktlen)
caddr_t arg;
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u_char *pkt;
u_int pktlen;
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{
struct bpf_if *bp;
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struct bpf_d *d;
u_int slen;
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/*
* 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, memcpy);
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}
}
/*
* Copy data from an mbuf chain into a buffer. This code is derived
* from m_copydata in sys/uipc_mbuf.c.
*/
static void *
bpf_mcpy(dst_arg, src_arg, len)
void *dst_arg;
const void *src_arg;
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size_t len;
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{
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const struct mbuf *m;
u_int count;
u_char *dst;
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m = src_arg;
dst = dst_arg;
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while (len > 0) {
if (m == 0)
panic("bpf_mcpy");
count = min(m->m_len, len);
memcpy((caddr_t)dst, mtod(m, caddr_t), count);
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m = m->m_next;
dst += count;
len -= count;
}
return(dst_arg);
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}
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
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*/
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;
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struct mbuf *m0;
pktlen = 0;
for (m0 = m; m0 != 0; m0 = m0->m_next)
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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_mcpy);
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}
}
/*
* 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. memcpy is passed in to copy contiguous chunks, while
* bpf_mcpy is passed in to copy mbuf chains. In the latter case,
* pkt is really an mbuf.
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*/
static void
catchpacket(d, pkt, pktlen, snaplen, cpfn)
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struct bpf_d *d;
u_char *pkt;
u_int pktlen, snaplen;
void *(*cpfn) __P((void *, const void *, size_t));
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{
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struct bpf_hdr *hp;
int totlen, curlen;
int hdrlen = d->bd_bif->bif_hdrlen;
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/*
* 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);
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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,
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* so drop the packet.
*/
++d->bd_dcount;
return;
}
ROTATE_BUFFERS(d);
bpf_wakeup(d);
curlen = 0;
}
else if (d->bd_immediate)
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/*
* 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);
microtime(&hp->bh_tstamp);
hp->bh_datalen = pktlen;
hp->bh_hdrlen = hdrlen;
/*
* Copy the packet data into the store buffer and update its length.
*/
(*cpfn)((u_char *)hp + hdrlen, pkt, (hp->bh_caplen = totlen - hdrlen));
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d->bd_slen = curlen + totlen;
}
/*
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* Initialize all nonzero fields of a descriptor.
*/
static int
bpf_allocbufs(d)
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struct bpf_d *d;
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{
d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK);
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d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK);
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)
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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_DEVBUF);
if (d->bd_hbuf != 0)
free(d->bd_hbuf, M_DEVBUF);
if (d->bd_fbuf != 0)
free(d->bd_fbuf, M_DEVBUF);
}
if (d->bd_filter)
free((caddr_t)d->bd_filter, M_DEVBUF);
D_MARKFREE(d);
}
/*
* Attach an interface to bpf. dlt is the link layer type; hdrlen is the
* fixed size of the link header (variable length headers not yet supported).
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*/
void
bpfattach(ifp, dlt, hdrlen)
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struct ifnet *ifp;
u_int dlt, hdrlen;
{
struct bpf_if *bp;
bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
if (bp == 0)
panic("bpfattach");
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bp->bif_dlist = 0;
bp->bif_driverp = (struct bpf_if **)&ifp->if_bpf;
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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
1993-03-21 12:45:37 +03:00
* performance reasons and to alleviate alignment restrictions).
*/
bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
1994-01-25 09:10:08 +03:00
#if 0
1996-10-13 06:10:01 +04:00
printf("bpf: %s attached\n", ifp->if_xname);
1994-01-25 09:10:08 +03:00
#endif
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}
2000-02-01 02:06:12 +03:00
/*
* Remove an interface from bpf.
*/
void
bpfdetach(ifp)
struct ifnet *ifp;
{
struct bpf_if *bp, **pbp;
2000-02-02 12:03:41 +03:00
struct bpf_d *d;
int i, s, cmaj;
/* locate the major number */
for (cmaj = 0; cmaj <= nchrdev; cmaj++)
if (cdevsw[cmaj].d_open == bpfopen)
break;
2000-03-14 02:52:25 +03:00
/* Nuke the vnodes for any open instances */
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for (i = 0; i < NBPFILTER; ++i) {
d = &bpf_dtab[i];
if (!D_ISFREE(d) && d->bd_bif != NULL &&
d->bd_bif->bif_ifp == ifp) {
/*
* Detach the descriptor from an interface now.
* It will be free'ed later by close routine.
*/
s = splnet();
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d->bd_promisc = 0; /* we can't touch device. */
bpf_detachd(d);
splx(s);
vdevgone(cmaj, i, i, VCHR);
}
}
2000-02-01 02:06:12 +03:00
for (bp = bpf_iflist, pbp = &bpf_iflist;
bp != NULL; pbp = &bp->bif_next, bp = bp->bif_next) {
if (bp->bif_ifp == ifp) {
*pbp = bp->bif_next;
free(bp, M_DEVBUF);
break;
}
}
}
/*
* Change the data link type of a BPF instance.
*/
void
bpf_change_type(ifp, dlt, hdrlen)
struct ifnet *ifp;
u_int dlt, hdrlen;
{
struct bpf_if *bp;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_driverp == (struct bpf_if **)&ifp->if_bpf)
break;
}
if (bp == NULL)
panic("bpf_change_type");
bp->bif_dlt = dlt;
/*
* 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;
}