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NetBSD/sys/net/bpf.c

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/* $NetBSD: bpf.c,v 1.105 2004/11/30 04:28:43 christos Exp $ */
/*
* 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. 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 8.4 (Berkeley) 1/9/95
* static char rcsid[] =
* "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp ";
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.105 2004/11/30 04:28:43 christos Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/buf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/tty.h>
#include <sys/uio.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/poll.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/slip.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>
#include <net/if_arc.h>
#include <net/if_ether.h>
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#if defined(_KERNEL_OPT)
#include "opt_bpf.h"
#include "sl.h"
#include "strip.h"
#endif
#ifndef BPF_BUFSIZE
/*
* 4096 is too small for FDDI frames. 8192 is too small for gigabit Ethernet
* jumbos (circa 9k), ATM, or Intel gig/10gig ethernet jumbos (16k).
*/
# define BPF_BUFSIZE 32768
#endif
#define PRINET 26 /* interruptible */
/*
* The default read buffer size, and limit for BIOCSBLEN, is sysctl'able.
* XXX the default values should be computed dynamically based
* on available memory size and available mbuf clusters.
*/
int bpf_bufsize = BPF_BUFSIZE;
int bpf_maxbufsize = BPF_DFLTBUFSIZE; /* XXX set dynamically, see above */
/*
* 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;
LIST_HEAD(, bpf_d) bpf_list;
static int bpf_allocbufs(struct bpf_d *);
static void bpf_deliver(struct bpf_if *,
void *(*cpfn)(void *, const void *, size_t),
void *, u_int, u_int, struct ifnet *);
static void bpf_freed(struct bpf_d *);
static void bpf_ifname(struct ifnet *, struct ifreq *);
static void *bpf_mcpy(void *, const void *, size_t);
static int bpf_movein(struct uio *, int, int,
struct mbuf **, struct sockaddr *);
static void bpf_attachd(struct bpf_d *, struct bpf_if *);
static void bpf_detachd(struct bpf_d *);
static int bpf_setif(struct bpf_d *, struct ifreq *);
static void bpf_timed_out(void *);
static __inline void
bpf_wakeup(struct bpf_d *);
static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
void *(*)(void *, const void *, size_t));
static void reset_d(struct bpf_d *);
static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
static int bpf_setdlt(struct bpf_d *, u_int);
static int bpf_read(struct file *, off_t *, struct uio *, struct ucred *,
int);
static int bpf_write(struct file *, off_t *, struct uio *, struct ucred *,
int);
static int bpf_ioctl(struct file *, u_long, void *, struct proc *);
static int bpf_poll(struct file *, int, struct proc *);
static int bpf_close(struct file *, struct proc *);
static int bpf_kqfilter(struct file *, struct knote *);
static const struct fileops bpf_fileops = {
bpf_read,
bpf_write,
bpf_ioctl,
fnullop_fcntl,
bpf_poll,
fbadop_stat,
bpf_close,
bpf_kqfilter,
};
dev_type_open(bpfopen);
const struct cdevsw bpf_cdevsw = {
bpfopen, noclose, noread, nowrite, noioctl,
nostop, notty, nopoll, nommap, nokqfilter,
};
static int
bpf_movein(uio, linktype, mtu, mp, sockp)
struct uio *uio;
int linktype;
int mtu;
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);
m = m_gethdr(M_WAIT, MT_DATA);
m->m_pkthdr.rcvif = 0;
m->m_pkthdr.len = len - hlen;
if (len > MHLEN - align) {
m_clget(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, void *), len, uio);
if (error)
goto bad;
if (hlen != 0) {
memcpy(sockp->sa_data, mtod(m, void *), hlen);
m->m_data += hlen; /* XXX */
len -= hlen;
}
m->m_len = len;
*mp = m;
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 splnet.
*/
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_driverp = 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) {
int error;
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");
}
/* 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.
*/
/*
* bpfilterattach() is called at boot time.
*/
/* ARGSUSED */
void
bpfilterattach(n)
int n;
{
LIST_INIT(&bpf_list);
}
/*
* Open ethernet device. Clones.
*/
/* ARGSUSED */
int
bpfopen(dev, flag, mode, p)
dev_t dev;
int flag;
int mode;
struct proc *p;
{
struct bpf_d *d;
struct file *fp;
int error, fd;
/* falloc() will use the descriptor for us. */
if ((error = falloc(p, &fp, &fd)) != 0)
return error;
d = malloc(sizeof(*d), M_DEVBUF, M_WAITOK);
(void)memset(d, 0, sizeof(*d));
d->bd_bufsize = bpf_bufsize;
d->bd_seesent = 1;
callout_init(&d->bd_callout);
LIST_INSERT_HEAD(&bpf_list, d, bd_list);
return fdclone(p, fp, fd, &bpf_fileops, d);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
static int
bpf_close(struct file *fp, struct proc *p)
{
struct bpf_d *d = fp->f_data;
int s;
s = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
if (d->bd_bif)
bpf_detachd(d);
splx(s);
bpf_freed(d);
LIST_REMOVE(d, bd_list);
free(d, M_DEVBUF);
fp->f_data = NULL;
return (0);
}
/*
* 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
bpf_read(struct file *fp, off_t *offp, struct uio *uio,
struct ucred *cred, int flags)
{
struct bpf_d *d = fp->f_data;
int timed_out;
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 = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
timed_out = (d->bd_state == BPF_TIMED_OUT);
d->bd_state = BPF_IDLE;
/*
* 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 (fp->f_flag & FNONBLOCK) {
if (d->bd_slen == 0) {
splx(s);
return (EWOULDBLOCK);
}
ROTATE_BUFFERS(d);
break;
}
if ((d->bd_immediate || timed_out) && 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(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;
}
if (error != 0)
goto done;
}
/*
* 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 = splnet();
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = 0;
d->bd_hlen = 0;
done:
splx(s);
return (error);
}
/*
* If there are processes sleeping on this descriptor, wake them up.
*/
static __inline void
bpf_wakeup(d)
struct bpf_d *d;
{
wakeup(d);
if (d->bd_async)
fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL);
selnotify(&d->bd_sel, 0);
/* XXX */
d->bd_sel.sel_pid = 0;
}
static void
bpf_timed_out(arg)
void *arg;
{
struct bpf_d *d = arg;
int s;
s = splnet();
if (d->bd_state == BPF_WAITING) {
d->bd_state = BPF_TIMED_OUT;
if (d->bd_slen != 0)
bpf_wakeup(d);
}
splx(s);
}
static int
bpf_write(struct file *fp, off_t *offp, struct uio *uio,
struct ucred *cred, int flags)
{
struct bpf_d *d = fp->f_data;
struct ifnet *ifp;
struct mbuf *m;
int error, s;
static struct sockaddr_storage dst;
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, ifp->if_mtu, &m,
(struct sockaddr *) &dst);
if (error)
return (error);
if (m->m_pkthdr.len > ifp->if_mtu)
return (EMSGSIZE);
if (d->bd_hdrcmplt)
dst.ss_family = pseudo_AF_HDRCMPLT;
s = splsoftnet();
error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL);
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 splnet.
*/
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;
d->bd_ccount = 0;
}
#ifdef BPF_KERN_FILTER
extern struct bpf_insn *bpf_tcp_filter;
extern struct bpf_insn *bpf_udp_filter;
#endif
/*
* 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.
*/
/* ARGSUSED */
static int
bpf_ioctl(struct file *fp, u_long cmd, void *addr, struct proc *p)
{
struct bpf_d *d = fp->f_data;
int s, error = 0;
#ifdef BPF_KERN_FILTER
struct bpf_insn **p;
#endif
s = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
splx(s);
switch (cmd) {
default:
error = EINVAL;
break;
/*
* Check for read packet available.
*/
case FIONREAD:
{
int n;
s = splnet();
n = d->bd_slen;
if (d->bd_hbuf)
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.
*/
case BIOCSBLEN:
if (d->bd_bif != 0)
error = EINVAL;
else {
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:
error = bpf_setf(d, 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, addr);
/* Free possible old filter */
if (cmd == BIOCSTCPF)
p = &bpf_tcp_filter;
else
p = &bpf_udp_filter;
if (*p != NULL)
free(*p, M_DEVBUF);
/* Steal new filter (noop if error) */
s = splnet();
*p = d->bd_filter;
d->bd_filter = NULL;
splx(s);
break;
#endif
/*
* Flush read packet buffer.
*/
case BIOCFLUSH:
s = splnet();
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();
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;
/*
* Get a list of supported device parameters.
*/
case BIOCGDLTLIST:
if (d->bd_bif == 0)
error = EINVAL;
else
error = bpf_getdltlist(d, addr);
break;
/*
* Set device parameters.
*/
case BIOCSDLT:
if (d->bd_bif == 0)
error = EINVAL;
else
error = bpf_setdlt(d, *(u_int *)addr);
break;
/*
* Set interface name.
*/
case BIOCGETIF:
if (d->bd_bif == 0)
error = EINVAL;
else
bpf_ifname(d->bd_bif->bif_ifp, addr);
break;
/*
* Set interface.
*/
case BIOCSETIF:
error = bpf_setif(d, addr);
break;
/*
* Set read timeout.
*/
case BIOCSRTIMEOUT:
{
struct timeval *tv = 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;
break;
}
/*
* Get read timeout.
*/
case BIOCGRTIMEOUT:
{
struct timeval *tv = 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 = addr;
bs->bs_recv = d->bd_rcount;
bs->bs_drop = d->bd_dcount;
bs->bs_capt = d->bd_ccount;
break;
}
case BIOCGSTATSOLD:
{
struct bpf_stat_old *bs = 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 = 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;
/*
* Get "see sent packets" flag
*/
case BIOCGSEESENT:
*(u_int *)addr = d->bd_seesent;
break;
/*
* Set "see sent" packets flag
*/
case BIOCSSEESENT:
d->bd_seesent = *(u_int *)addr;
break;
case FIONBIO: /* Non-blocking I/O */
/*
* No need to do anything special as we use IO_NDELAY in
* bpfread() as an indication of whether or not to block
* the read.
*/
break;
case FIOASYNC: /* Send signal on receive packets */
d->bd_async = *(int *)addr;
break;
case TIOCSPGRP: /* Process or group to send signals to */
case FIOSETOWN:
error = fsetown(p, &d->bd_pgid, cmd, addr);
break;
case TIOCGPGRP:
case FIOGETOWN:
error = fgetown(p, d->bd_pgid, cmd, addr);
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.
*/
int
bpf_setf(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();
d->bd_filter = 0;
reset_d(d);
splx(s);
if (old != 0)
free(old, M_DEVBUF);
return (0);
}
flen = fp->bf_len;
if (flen > BPF_MAXINSNS)
return (EINVAL);
size = flen * sizeof(*fp->bf_insns);
fcode = malloc(size, M_DEVBUF, M_WAITOK);
if (copyin(fp->bf_insns, fcode, size) == 0 &&
bpf_validate(fcode, (int)flen)) {
s = splnet();
d->bd_filter = fcode;
reset_d(d);
splx(s);
if (old != 0)
free(old, M_DEVBUF);
return (0);
}
free(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.
*/
static int
bpf_setif(struct bpf_d *d, struct ifreq *ifr)
{
struct bpf_if *bp;
char *cp;
int unit_seen, i, s, error;
/*
* Make sure the provided name has a unit number, and default
* it to '0' if not specified.
* XXX This is ugly ... do this differently?
*/
unit_seen = 0;
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';
}
}
/*
* 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)
continue;
/* skip additional entry */
if (bp->bif_driverp != (struct bpf_if **)&ifp->if_bpf)
continue;
/*
* We found the requested interface.
* Allocate the packet buffers if we need to.
* If we're already attached to requested interface,
* just flush the buffer.
*/
if (d->bd_sbuf == 0) {
error = bpf_allocbufs(d);
if (error != 0)
return (error);
}
s = splnet();
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);
}
/*
* Copy the interface name to the ifreq.
*/
static void
bpf_ifname(struct ifnet *ifp, struct ifreq *ifr)
{
memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
}
/*
* Support for poll() system call
*
* Return true iff the specific operation will not block indefinitely - with
* the assumption that it is safe to positively acknowledge a request for the
* ability to write to the BPF device.
* Otherwise, return false but make a note that a selwakeup() must be done.
*/
static int
bpf_poll(struct file *fp, int events, struct proc *p)
{
struct bpf_d *d = fp->f_data;
int s = splnet();
int revents;
revents = events & (POLLOUT | POLLWRNORM);
if (events & (POLLIN | POLLRDNORM)) {
/*
* An imitation of the FIONREAD ioctl code.
*/
if ((d->bd_hlen != 0) ||
(d->bd_immediate && d->bd_slen != 0)) {
revents |= events & (POLLIN | POLLRDNORM);
} else if (d->bd_state == BPF_TIMED_OUT) {
if (d->bd_slen != 0)
revents |= events & (POLLIN | POLLRDNORM);
else
revents |= events & POLLIN;
} else {
selrecord(p, &d->bd_sel);
/* Start the read timeout if necessary */
if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) {
callout_reset(&d->bd_callout, d->bd_rtout,
bpf_timed_out, d);
d->bd_state = BPF_WAITING;
}
}
}
splx(s);
return (revents);
}
static void
filt_bpfrdetach(struct knote *kn)
{
struct bpf_d *d = kn->kn_hook;
int s;
s = splnet();
SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext);
splx(s);
}
static int
filt_bpfread(struct knote *kn, long hint)
{
struct bpf_d *d = kn->kn_hook;
kn->kn_data = d->bd_hlen;
if (d->bd_immediate)
kn->kn_data += d->bd_slen;
return (kn->kn_data > 0);
}
static const struct filterops bpfread_filtops =
{ 1, NULL, filt_bpfrdetach, filt_bpfread };
static int
bpf_kqfilter(struct file *fp, struct knote *kn)
{
struct bpf_d *d = fp->f_data;
struct klist *klist;
int s;
switch (kn->kn_filter) {
case EVFILT_READ:
klist = &d->bd_sel.sel_klist;
kn->kn_fop = &bpfread_filtops;
break;
default:
return (1);
}
kn->kn_hook = d;
s = splnet();
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
splx(s);
return (0);
}
/*
* 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(void *arg, u_char *pkt, u_int pktlen)
{
struct bpf_if *bp;
struct bpf_d *d;
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 = 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);
}
}
/*
* 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(void *dst_arg, const void *src_arg, size_t len)
{
const struct mbuf *m;
u_int count;
u_char *dst;
m = src_arg;
dst = dst_arg;
while (len > 0) {
if (m == 0)
panic("bpf_mcpy");
count = min(m->m_len, len);
memcpy(dst, mtod(m, void *), count);
m = m->m_next;
dst += count;
len -= count;
}
return (dst_arg);
}
/*
* Dispatch a packet to all the listeners on interface bp.
*
* marg pointer to the packet, either a data buffer or an mbuf chain
* buflen buffer length, if marg is a data buffer
* cpfn a function that can copy marg into the listener's buffer
* pktlen length of the packet
* rcvif either NULL or the interface the packet came in on.
*/
static __inline void
bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t),
void *marg, u_int pktlen, u_int buflen, struct ifnet *rcvif)
{
u_int slen;
struct bpf_d *d;
for (d = bp->bif_dlist; d != 0; d = d->bd_next) {
if (!d->bd_seesent && (rcvif == NULL))
continue;
++d->bd_rcount;
slen = bpf_filter(d->bd_filter, marg, pktlen, buflen);
if (slen != 0)
catchpacket(d, marg, pktlen, slen, cpfn);
}
}
/*
* Incoming linkage from device drivers, when the head of the packet is in
* a buffer, and the tail is in an mbuf chain.
*/
void
bpf_mtap2(void *arg, void *data, u_int dlen, struct mbuf *m)
{
struct bpf_if *bp = arg;
u_int pktlen;
struct mbuf mb;
pktlen = m_length(m) + dlen;
/*
* Craft on-stack mbuf suitable for passing to bpf_filter.
* Note that we cut corners here; we only setup what's
* absolutely needed--this mbuf should never go anywhere else.
*/
(void)memset(&mb, 0, sizeof(mb));
mb.m_next = m;
mb.m_data = data;
mb.m_len = dlen;
bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif);
}
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
*/
void
bpf_mtap(void *arg, struct mbuf *m)
{
void *(*cpfn)(void *, const void *, size_t);
struct bpf_if *bp = arg;
u_int pktlen, buflen;
void *marg;
pktlen = m_length(m);
if (pktlen == m->m_len) {
cpfn = memcpy;
marg = mtod(m, void *);
buflen = pktlen;
} else {
cpfn = bpf_mcpy;
marg = m;
buflen = 0;
}
bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif);
}
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
void
bpf_mtap_af(void *arg, u_int32_t af, struct mbuf *m)
{
struct mbuf m0;
m0.m_flags = 0;
m0.m_next = m;
m0.m_len = 4;
m0.m_data = (char *)&af;
bpf_mtap(arg, &m0);
}
void
bpf_mtap_et(void *arg, u_int16_t et, struct mbuf *m)
{
struct mbuf m0;
m0.m_flags = 0;
m0.m_next = m;
m0.m_len = 14;
m0.m_data = m0.m_dat;
((u_int32_t *)m0.m_data)[0] = 0;
((u_int32_t *)m0.m_data)[1] = 0;
((u_int32_t *)m0.m_data)[2] = 0;
((u_int16_t *)m0.m_data)[6] = et;
bpf_mtap(arg, &m0);
}
#if NSL > 0 || NSTRIP > 0
/*
* Put the SLIP pseudo-"link header" in place.
* Note this M_PREPEND() should never fail,
* swince we know we always have enough space
* in the input buffer.
*/
void
bpf_mtap_sl_in(void *arg, u_char *chdr, struct mbuf **m)
{
int s;
u_char *hp;
M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT);
if (*m == NULL)
return;
hp = mtod(*m, u_char *);
hp[SLX_DIR] = SLIPDIR_IN;
(void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
s = splnet();
bpf_mtap(arg, *m);
splx(s);
m_adj(*m, SLIP_HDRLEN);
}
/*
* Put the SLIP pseudo-"link header" in
* place. The compressed header is now
* at the beginning of the mbuf.
*/
void
bpf_mtap_sl_out(void *arg, u_char *chdr, struct mbuf *m)
{
struct mbuf m0;
u_char *hp;
int s;
m0.m_flags = 0;
m0.m_next = m;
m0.m_data = m0.m_dat;
m0.m_len = SLIP_HDRLEN;
hp = mtod(&m0, u_char *);
hp[SLX_DIR] = SLIPDIR_OUT;
(void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
s = splnet();
bpf_mtap(arg, &m0);
splx(s);
m_freem(m);
}
#endif
/*
* 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.
*/
static void
catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
void *(*cpfn)(void *, const void *, size_t))
{
struct bpf_hdr *hp;
int totlen, curlen;
int hdrlen = d->bd_bif->bif_hdrlen;
++d->bd_ccount;
/*
* 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;
}
/*
* 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));
d->bd_slen = curlen + totlen;
/*
* Call bpf_wakeup after bd_slen has been updated so that kevent(2)
* will cause filt_bpfread() to be called with it adjusted.
*/
if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT)
/*
* Immediate mode is set, or the read timeout has
* already expired during a select call. A packet
* arrived, so the reader should be woken up.
*/
bpf_wakeup(d);
}
/*
* Initialize all nonzero fields of a descriptor.
*/
static int
bpf_allocbufs(struct bpf_d *d)
{
d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
if (!d->bd_fbuf)
return (ENOBUFS);
d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
if (!d->bd_sbuf) {
free(d->bd_fbuf, M_DEVBUF);
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(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(d->bd_filter, M_DEVBUF);
}
/*
* 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).
*/
void
bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
{
bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf);
}
/*
* Attach additional dlt for a interface to bpf. dlt is the link layer type;
* hdrlen is the fixed size of the link header for the specified dlt
* (variable length headers not yet supported).
*/
void
bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, void *driverp)
{
struct bpf_if *bp;
bp = malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
if (bp == 0)
panic("bpfattach");
bp->bif_dlist = 0;
bp->bif_driverp = 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;
#if 0
printf("bpf: %s attached\n", ifp->if_xname);
#endif
}
/*
* Remove an interface from bpf.
*/
void
bpfdetach(struct ifnet *ifp)
{
struct bpf_if *bp, **pbp;
struct bpf_d *d;
int s;
/* Nuke the vnodes for any open instances */
for (d = LIST_FIRST(&bpf_list); d != NULL; d = LIST_NEXT(d, bd_list)) {
if (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();
d->bd_promisc = 0; /* we can't touch device. */
bpf_detachd(d);
splx(s);
}
}
again:
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);
goto again;
}
}
}
/*
* Change the data link type of a interface.
*/
void
bpf_change_type(struct ifnet *ifp, u_int dlt, u_int 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;
}
/*
* Get a list of available data link type of the interface.
*/
static int
bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
{
int n, error;
struct ifnet *ifp;
struct bpf_if *bp;
ifp = d->bd_bif->bif_ifp;
n = 0;
error = 0;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_ifp != ifp)
continue;
if (bfl->bfl_list != NULL) {
if (n >= bfl->bfl_len)
return ENOMEM;
error = copyout(&bp->bif_dlt,
bfl->bfl_list + n, sizeof(u_int));
}
n++;
}
bfl->bfl_len = n;
return error;
}
/*
* Set the data link type of a BPF instance.
*/
static int
bpf_setdlt(struct bpf_d *d, u_int dlt)
{
int s, error, opromisc;
struct ifnet *ifp;
struct bpf_if *bp;
if (d->bd_bif->bif_dlt == dlt)
return 0;
ifp = d->bd_bif->bif_ifp;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
break;
}
if (bp == NULL)
return EINVAL;
s = splnet();
opromisc = d->bd_promisc;
bpf_detachd(d);
bpf_attachd(d, bp);
reset_d(d);
if (opromisc) {
error = ifpromisc(bp->bif_ifp, 1);
if (error)
printf("%s: bpf_setdlt: ifpromisc failed (%d)\n",
bp->bif_ifp->if_xname, error);
else
d->bd_promisc = 1;
}
splx(s);
return 0;
}
static int
sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS)
{
int newsize, error;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &newsize;
newsize = bpf_maxbufsize;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return (error);
if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE)
return (EINVAL);
bpf_maxbufsize = newsize;
return (0);
}
SYSCTL_SETUP(sysctl_net_bfp_setup, "sysctl net.bpf subtree setup")
{
struct sysctlnode *node;
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "net", NULL,
NULL, 0, NULL, 0,
CTL_NET, CTL_EOL);
node = NULL;
sysctl_createv(clog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "bpf",
SYSCTL_DESCR("BPF options"),
NULL, 0, NULL, 0,
CTL_NET, CTL_CREATE, CTL_EOL);
if (node != NULL)
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maxbufsize",
SYSCTL_DESCR("Maximum size for data capture buffer"),
sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0,
CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
}
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