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|
/* $OpenBSD: bpf.c,v 1.74 2009/10/26 18:22:58 claudio Exp $ */
/* $NetBSD: bpf.c,v 1.33 1997/02/21 23:59:35 thorpej 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 8.2 (Berkeley) 3/28/94
*/
#include "bpfilter.h"
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include "vlan.h"
#if NVLAN > 0
#include <net/if_vlan_var.h>
#endif
#define BPF_BUFSIZE 32768
#define PRINET 26 /* interruptible */
/* from kern/kern_clock.c; incremented each clock tick. */
extern int ticks;
/*
* The default read buffer size is patchable.
*/
int bpf_bufsize = BPF_BUFSIZE;
int bpf_maxbufsize = BPF_MAXBUFSIZE;
/*
* bpf_iflist is the list of interfaces; each corresponds to an ifnet
* bpf_d_list is the list of descriptors
*/
struct bpf_if *bpf_iflist;
LIST_HEAD(, bpf_d) bpf_d_list;
int bpf_allocbufs(struct bpf_d *);
void bpf_freed(struct bpf_d *);
void bpf_ifname(struct ifnet *, struct ifreq *);
void bpf_mcopy(const void *, void *, size_t);
int bpf_movein(struct uio *, u_int, struct mbuf **,
struct sockaddr *, struct bpf_insn *);
void bpf_attachd(struct bpf_d *, struct bpf_if *);
void bpf_detachd(struct bpf_d *);
int bpf_setif(struct bpf_d *, struct ifreq *);
int bpfpoll(dev_t, int, struct proc *);
int bpfkqfilter(dev_t, struct knote *);
void bpf_wakeup(struct bpf_d *);
void bpf_catchpacket(struct bpf_d *, u_char *, size_t, size_t,
void (*)(const void *, void *, size_t));
void bpf_reset_d(struct bpf_d *);
int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
int bpf_setdlt(struct bpf_d *, u_int);
void filt_bpfrdetach(struct knote *);
int filt_bpfread(struct knote *, long);
struct bpf_d *bpfilter_lookup(int);
struct bpf_d *bpfilter_create(int);
void bpfilter_destroy(struct bpf_d *);
int
bpf_movein(struct uio *uio, u_int linktype, struct mbuf **mp,
struct sockaddr *sockp, struct bpf_insn *filter)
{
struct mbuf *m;
struct m_tag *mtag;
int error;
u_int hlen;
u_int len;
u_int slen;
/*
* 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_PPP:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
break;
case DLT_EN10MB:
sockp->sa_family = AF_UNSPEC;
/* XXX Would MAXLINKHDR be better? */
hlen = ETHER_HDR_LEN;
break;
case DLT_FDDI:
sockp->sa_family = AF_UNSPEC;
/* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */
hlen = 24;
break;
case DLT_IEEE802_11:
case DLT_IEEE802_11_RADIO:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
break;
case DLT_RAW:
case DLT_NULL:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
break;
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;
default:
return (EIO);
}
len = uio->uio_resid;
if (len > MCLBYTES)
return (EIO);
MGETHDR(m, M_WAIT, MT_DATA);
m->m_pkthdr.rcvif = 0;
m->m_pkthdr.len = len - hlen;
if (len > MHLEN) {
MCLGET(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0) {
error = ENOBUFS;
goto bad;
}
}
m->m_len = len;
*mp = m;
error = uiomove(mtod(m, caddr_t), len, uio);
if (error)
goto bad;
slen = bpf_filter(filter, mtod(m, u_char *), len, len);
if (slen < len) {
error = EPERM;
goto bad;
}
if (m->m_len < hlen) {
error = EPERM;
goto bad;
}
/*
* Make room for link header, and copy it to sockaddr
*/
if (hlen != 0) {
bcopy(m->m_data, sockp->sa_data, hlen);
m->m_len -= hlen;
m->m_data += hlen; /* XXX */
}
/*
* Prepend the data link type as a mbuf tag
*/
mtag = m_tag_get(PACKET_TAG_DLT, sizeof(u_int), M_NOWAIT);
if (mtag == NULL)
return (ENOMEM);
*(u_int *)(mtag + 1) = linktype;
m_tag_prepend(m, mtag);
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.
*/
void
bpf_attachd(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.
*/
void
bpf_detachd(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;
error = ifpromisc(bp->bif_ifp, 0);
if (error && !(error == EINVAL || error == ENODEV))
/*
* 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_driverp = 0;
d->bd_bif = 0;
}
/*
* Reference count access to descriptor buffers
*/
#define D_GET(d) ((d)->bd_ref++)
#define D_PUT(d) bpf_freed(d)
/*
* bpfilterattach() is called at boot time in new systems. We do
* nothing here since old systems will not call this.
*/
/* ARGSUSED */
void
bpfilterattach(int n)
{
LIST_INIT(&bpf_d_list);
}
/*
* Open ethernet device. Returns ENXIO for illegal minor device number,
* EBUSY if file is open by another process.
*/
/* ARGSUSED */
int
bpfopen(dev_t dev, int flag, int mode, struct proc *p)
{
struct bpf_d *d;
/* create on demand */
if ((d = bpfilter_create(minor(dev))) == NULL)
return (EBUSY);
/* Mark "free" and do most initialization. */
d->bd_bufsize = bpf_bufsize;
d->bd_sig = SIGIO;
D_GET(d);
return (0);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
int
bpfclose(dev_t dev, int flag, int mode, struct proc *p)
{
struct bpf_d *d;
int s;
d = bpfilter_lookup(minor(dev));
s = splnet();
if (d->bd_bif)
bpf_detachd(d);
bpf_wakeup(d);
D_PUT(d);
splx(s);
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
*/
int
bpfread(dev_t dev, struct uio *uio, int ioflag)
{
struct bpf_d *d;
int error;
int s;
d = bpfilter_lookup(minor(dev));
if (d->bd_bif == 0)
return (ENXIO);
/*
* Restrict application to use a buffer the same size as
* as kernel buffers.
*/
if (uio->uio_resid != d->bd_bufsize)
return (EINVAL);
s = splnet();
D_GET(d);
/*
* bd_rdStart is tagged when we start the read, iff there's a timeout.
* we can then figure out when we're done reading.
*/
if (d->bd_rtout != -1 && d->bd_rdStart == 0)
d->bd_rdStart = ticks;
else
d->bd_rdStart = 0;
/*
* 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_bif == NULL) {
/* interface is gone */
if (d->bd_slen == 0) {
D_PUT(d);
splx(s);
return (EIO);
}
ROTATE_BUFFERS(d);
break;
}
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 ((d->bd_rtout != -1) ||
(d->bd_rdStart + d->bd_rtout) < ticks) {
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) {
D_PUT(d);
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) {
D_PUT(d);
splx(s);
return (0);
}
ROTATE_BUFFERS(d);
break;
}
}
/*
* At this point, we know we have something in the hold slot.
*/
splx(s);
/*
* Move data from hold buffer into user space.
* We know the entire buffer is transferred since
* we checked above that the read buffer is bpf_bufsize bytes.
*/
error = uiomove(d->bd_hbuf, d->bd_hlen, uio);
s = splnet();
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = 0;
d->bd_hlen = 0;
D_PUT(d);
splx(s);
return (error);
}
/*
* If there are processes sleeping on this descriptor, wake them up.
*/
void
bpf_wakeup(struct bpf_d *d)
{
wakeup((caddr_t)d);
if (d->bd_async && d->bd_sig)
csignal(d->bd_pgid, d->bd_sig,
d->bd_siguid, d->bd_sigeuid);
selwakeup(&d->bd_sel);
/* XXX */
d->bd_sel.si_selpid = 0;
KNOTE(&d->bd_sel.si_note, 0);
}
int
bpfwrite(dev_t dev, struct uio *uio, int ioflag)
{
struct bpf_d *d;
struct ifnet *ifp;
struct mbuf *m;
int error, s;
struct sockaddr_storage dst;
d = bpfilter_lookup(minor(dev));
if (d->bd_bif == 0)
return (ENXIO);
ifp = d->bd_bif->bif_ifp;
if ((ifp->if_flags & IFF_UP) == 0)
return (ENETDOWN);
if (uio->uio_resid == 0)
return (0);
error = bpf_movein(uio, d->bd_bif->bif_dlt, &m,
(struct sockaddr *)&dst, d->bd_wfilter);
if (error)
return (error);
if (m->m_pkthdr.len > ifp->if_mtu) {
m_freem(m);
return (EMSGSIZE);
}
m->m_pkthdr.rdomain = ifp->if_rdomain;
if (d->bd_hdrcmplt)
dst.ss_family = pseudo_AF_HDRCMPLT;
s = splsoftnet();
error = (*ifp->if_output)(ifp, m, (struct sockaddr *)&dst,
(struct rtentry *)0);
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.
*/
void
bpf_reset_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.
* BIOCGBLEN Get buffer len [for read()].
* BIOCSETF Set ethernet read filter.
* BIOCFLUSH Flush read packet buffer.
* BIOCPROMISC Put interface into promiscuous mode.
* BIOCGDLTLIST Get supported link layer types.
* BIOCGDLT Get link layer type.
* BIOCSDLT Set 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.
* BIOCGHDRCMPLT Get "header already complete" flag
* BIOCSHDRCMPLT Set "header already complete" flag
*/
/* ARGSUSED */
int
bpfioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
{
struct bpf_d *d;
int s, error = 0;
d = bpfilter_lookup(minor(dev));
if (d->bd_locked && suser(p, 0) != 0) {
/* list of allowed ioctls when locked and not root */
switch (cmd) {
case BIOCGBLEN:
case BIOCFLUSH:
case BIOCGDLT:
case BIOCGDLTLIST:
case BIOCGETIF:
case BIOCGRTIMEOUT:
case BIOCGSTATS:
case BIOCVERSION:
case BIOCGRSIG:
case BIOCGHDRCMPLT:
case FIONREAD:
case BIOCLOCK:
case BIOCSRTIMEOUT:
case BIOCIMMEDIATE:
case TIOCGPGRP:
case BIOCGDIRFILT:
break;
default:
return (EPERM);
}
}
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, (struct bpf_program *)addr, 0);
break;
/*
* Set link layer write filter.
*/
case BIOCSETWF:
error = bpf_setf(d, (struct bpf_program *)addr, 1);
break;
/*
* Flush read packet buffer.
*/
case BIOCFLUSH:
s = splnet();
bpf_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 a list of supported device parameters.
*/
case BIOCGDLTLIST:
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_getdltlist(d, (struct bpf_dltlist *)addr);
break;
/*
* Get device parameters.
*/
case BIOCGDLT:
if (d->bd_bif == 0)
error = EINVAL;
else
*(u_int *)addr = d->bd_bif->bif_dlt;
break;
/*
* Set device parameters.
*/
case BIOCSDLT:
if (d->bd_bif == NULL)
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, (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;
/* 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 = (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 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 BIOCLOCK: /* set "locked" flag (no reset) */
d->bd_locked = 1;
break;
case BIOCGFILDROP: /* get "filter-drop" flag */
*(u_int *)addr = d->bd_fildrop;
break;
case BIOCSFILDROP: /* set "filter-drop" flag */
d->bd_fildrop = *(u_int *)addr ? 1 : 0;
break;
case BIOCGDIRFILT: /* get direction filter */
*(u_int *)addr = d->bd_dirfilt;
break;
case BIOCSDIRFILT: /* set direction filter */
d->bd_dirfilt = (*(u_int *)addr) &
(BPF_DIRECTION_IN|BPF_DIRECTION_OUT);
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;
d->bd_siguid = p->p_cred->p_ruid;
d->bd_sigeuid = p->p_ucred->cr_uid;
break;
case TIOCGPGRP:
*(int *)addr = d->bd_pgid;
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.
*/
int
bpf_setf(struct bpf_d *d, struct bpf_program *fp, int wf)
{
struct bpf_insn *fcode, *old;
u_int flen, size;
int s;
old = wf ? d->bd_wfilter : d->bd_rfilter;
if (fp->bf_insns == 0) {
if (fp->bf_len != 0)
return (EINVAL);
s = splnet();
if (wf)
d->bd_wfilter = 0;
else
d->bd_rfilter = 0;
bpf_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();
if (wf)
d->bd_wfilter = fcode;
else
d->bd_rfilter = fcode;
bpf_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.
*/
int
bpf_setif(struct bpf_d *d, struct ifreq *ifr)
{
struct bpf_if *bp, *candidate = NULL;
int s, error;
/*
* 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;
/*
* We found the requested interface.
*/
if (candidate == NULL || candidate->bif_dlt > bp->bif_dlt)
candidate = bp;
}
if (candidate != NULL) {
/*
* 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 (candidate != d->bd_bif) {
if (d->bd_bif)
/*
* Detach if attached to something else.
*/
bpf_detachd(d);
bpf_attachd(d, candidate);
}
bpf_reset_d(d);
splx(s);
return (0);
}
/* Not found. */
return (ENXIO);
}
/*
* Copy the interface name to the ifreq.
*/
void
bpf_ifname(struct ifnet *ifp, struct ifreq *ifr)
{
bcopy(ifp->if_xname, ifr->ifr_name, IFNAMSIZ);
}
/*
* Support for poll() system call
*/
int
bpfpoll(dev_t dev, int events, struct proc *p)
{
struct bpf_d *d;
int s, revents;
revents = events & (POLLIN | POLLRDNORM);
if (revents == 0)
return (0); /* only support reading */
/*
* An imitation of the FIONREAD ioctl code.
*/
d = bpfilter_lookup(minor(dev));
/*
* XXX The USB stack manages it to trigger some race condition
* which causes bpfilter_lookup to return NULL when a USB device
* gets detached while it is up and has an open bpf handler (e.g.
* dhclient). We still should recheck if we can fix the root
* cause of this issue.
*/
if (d == NULL)
return (POLLERR);
s = splnet();
if (d->bd_hlen == 0 && (!d->bd_immediate || d->bd_slen == 0)) {
revents = 0; /* no data waiting */
/*
* if there's a timeout, mark the time we started waiting.
*/
if (d->bd_rtout != -1 && d->bd_rdStart == 0)
d->bd_rdStart = ticks;
selrecord(p, &d->bd_sel);
}
splx(s);
return (revents);
}
struct filterops bpfread_filtops =
{ 1, NULL, filt_bpfrdetach, filt_bpfread };
int
bpfkqfilter(dev_t dev, struct knote *kn)
{
struct bpf_d *d;
struct klist *klist;
int s;
d = bpfilter_lookup(minor(dev));
switch (kn->kn_filter) {
case EVFILT_READ:
klist = &d->bd_sel.si_note;
kn->kn_fop = &bpfread_filtops;
break;
default:
return (1);
}
kn->kn_hook = (caddr_t)((u_long)dev);
s = splnet();
D_GET(d);
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
splx(s);
return (0);
}
void
filt_bpfrdetach(struct knote *kn)
{
dev_t dev = (dev_t)((u_long)kn->kn_hook);
struct bpf_d *d;
int s;
d = bpfilter_lookup(minor(dev));
s = splnet();
SLIST_REMOVE(&d->bd_sel.si_note, kn, knote, kn_selnext);
D_PUT(d);
splx(s);
}
int
filt_bpfread(struct knote *kn, long hint)
{
dev_t dev = (dev_t)((u_long)kn->kn_hook);
struct bpf_d *d;
d = bpfilter_lookup(minor(dev));
kn->kn_data = d->bd_hlen;
if (d->bd_immediate)
kn->kn_data += d->bd_slen;
return (kn->kn_data > 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.
*/
int
bpf_tap(caddr_t arg, u_char *pkt, u_int pktlen, u_int direction)
{
struct bpf_if *bp;
struct bpf_d *d;
size_t slen;
int drop = 0;
/*
* 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;
if ((direction & d->bd_dirfilt) != 0)
slen = 0;
else
slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
if (slen != 0) {
bpf_catchpacket(d, pkt, pktlen, slen, bcopy);
if (d->bd_fildrop)
drop++;
}
}
return (drop);
}
/*
* Copy data from an mbuf chain into a buffer. This code is derived
* from m_copydata in sys/uipc_mbuf.c.
*/
void
bpf_mcopy(const void *src_arg, void *dst_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_mcopy");
count = min(m->m_len, len);
bcopy(mtod(m, caddr_t), (caddr_t)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(caddr_t arg, struct mbuf *m, u_int direction)
{
struct bpf_if *bp = (struct bpf_if *)arg;
struct bpf_d *d;
size_t pktlen, slen;
struct mbuf *m0;
if (m == NULL)
return;
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;
if ((direction & d->bd_dirfilt) != 0)
slen = 0;
else
slen = bpf_filter(d->bd_rfilter, (u_char *)m,
pktlen, 0);
if (slen == 0)
continue;
bpf_catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy);
if (d->bd_fildrop)
m->m_flags |= M_FILDROP;
}
}
/*
* Incoming linkage from device drivers, where we have a mbuf chain
* but need to prepend some arbitrary header from a linear buffer.
*
* Con up a minimal dummy header to pacify bpf. Allocate (only) a
* struct m_hdr on the stack. This is safe as bpf only reads from the
* fields in this header that we initialize, and will not try to free
* it or keep a pointer to it.
*/
void
bpf_mtap_hdr(caddr_t arg, caddr_t data, u_int dlen, struct mbuf *m,
u_int direction)
{
struct m_hdr mh;
mh.mh_flags = 0;
mh.mh_next = m;
mh.mh_len = dlen;
mh.mh_data = data;
bpf_mtap(arg, (struct mbuf *) &mh, direction);
m->m_flags |= mh.mh_flags & M_FILDROP;
}
/*
* Incoming linkage from device drivers, where we have a mbuf chain
* but need to prepend the address family.
*
* Con up a minimal dummy header to pacify bpf. We allocate (only) a
* struct m_hdr on the stack. This is safe as bpf only reads from the
* fields in this header that we initialize, and will not try to free
* it or keep a pointer to it.
*/
void
bpf_mtap_af(caddr_t arg, u_int32_t af, struct mbuf *m, u_int direction)
{
struct m_hdr mh;
mh.mh_flags = 0;
mh.mh_next = m;
mh.mh_len = 4;
mh.mh_data = (caddr_t)⁡
bpf_mtap(arg, (struct mbuf *) &mh, direction);
m->m_flags |= mh.mh_flags & M_FILDROP;
}
/*
* Incoming linkage from device drivers, where we have a mbuf chain
* but need to prepend a VLAN encapsulation header.
*
* Con up a minimal dummy header to pacify bpf. Allocate (only) a
* struct m_hdr on the stack. This is safe as bpf only reads from the
* fields in this header that we initialize, and will not try to free
* it or keep a pointer to it.
*/
void
bpf_mtap_ether(caddr_t arg, struct mbuf *m, u_int direction)
{
#if NVLAN > 0
struct m_hdr mh;
struct ether_vlan_header evh;
if ((m->m_flags & M_VLANTAG) == 0)
#endif
{
bpf_mtap(arg, m, direction);
return;
}
#if NVLAN > 0
bcopy(mtod(m, char *), &evh, ETHER_HDR_LEN);
evh.evl_proto = evh.evl_encap_proto;
evh.evl_encap_proto = htons(ETHERTYPE_VLAN);
evh.evl_tag = htons(m->m_pkthdr.ether_vtag);
m->m_len -= ETHER_HDR_LEN;
m->m_data += ETHER_HDR_LEN;
mh.mh_flags = 0;
mh.mh_next = m;
mh.mh_len = sizeof(evh);
mh.mh_data = (caddr_t)&evh;
bpf_mtap(arg, (struct mbuf *) &mh, direction);
m->m_flags |= mh.mh_flags & M_FILDROP;
m->m_len += ETHER_HDR_LEN;
m->m_data -= ETHER_HDR_LEN;
#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. 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.
*/
void
bpf_catchpacket(struct bpf_d *d, u_char *pkt, size_t pktlen, size_t snaplen,
void (*cpfn)(const void *, void *, size_t))
{
struct bpf_hdr *hp;
int totlen, curlen;
int hdrlen = d->bd_bif->bif_hdrlen;
struct timeval tv;
/*
* 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(&tv);
hp->bh_tstamp.tv_sec = tv.tv_sec;
hp->bh_tstamp.tv_usec = tv.tv_usec;
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;
if (d->bd_immediate) {
/*
* Immediate mode is set. A packet arrived so any
* reads should be woken up.
*/
bpf_wakeup(d);
}
if (d->bd_rdStart && (d->bd_rtout + d->bd_rdStart < ticks)) {
/*
* we could be selecting on the bpf, and we
* may have timeouts set. We got here by getting
* a packet, so wake up the reader.
*/
if (d->bd_fbuf) {
d->bd_rdStart = 0;
ROTATE_BUFFERS(d);
bpf_wakeup(d);
}
}
}
/*
* Initialize all nonzero fields of a descriptor.
*/
int
bpf_allocbufs(struct bpf_d *d)
{
d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
if (d->bd_fbuf == NULL)
return (ENOBUFS);
d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT);
if (d->bd_sbuf == NULL) {
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
* when the reference count drops to zero.
*/
void
bpf_freed(struct bpf_d *d)
{
if (--d->bd_ref > 0)
return;
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_rfilter)
free((caddr_t)d->bd_rfilter, M_DEVBUF);
if (d->bd_wfilter)
free((caddr_t)d->bd_wfilter, M_DEVBUF);
bpfilter_destroy(d);
}
/*
* 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(caddr_t *driverp, struct ifnet *ifp, u_int dlt, u_int hdrlen)
{
struct bpf_if *bp;
bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
if (bp == 0)
panic("bpfattach");
bp->bif_dlist = 0;
bp->bif_driverp = (struct bpf_if **)driverp;
bp->bif_ifp = ifp;
bp->bif_dlt = dlt;
bp->bif_next = bpf_iflist;
bpf_iflist = bp;
*bp->bif_driverp = NULL;
/*
* 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;
}
/* Detach an interface from its attached bpf device. */
void
bpfdetach(struct ifnet *ifp)
{
struct bpf_if *bp, *nbp, **pbp = &bpf_iflist;
struct bpf_d *bd;
int maj;
for (bp = bpf_iflist; bp; bp = nbp) {
nbp= bp->bif_next;
if (bp->bif_ifp == ifp) {
*pbp = nbp;
/* Locate the major number. */
for (maj = 0; maj < nchrdev; maj++)
if (cdevsw[maj].d_open == bpfopen)
break;
for (bd = bp->bif_dlist; bd; bd = bp->bif_dlist) {
struct bpf_d *d;
/*
* Locate the minor number and nuke the vnode
* for any open instance.
*/
LIST_FOREACH(d, &bpf_d_list, bd_list)
if (d == bd) {
vdevgone(maj, d->bd_unit,
d->bd_unit, VCHR);
break;
}
}
free(bp, M_DEVBUF);
} else
pbp = &bp->bif_next;
}
ifp->if_bpf = NULL;
}
int
bpf_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
size_t newlen)
{
int newval;
int error;
if (namelen != 1)
return (ENOTDIR);
switch (name[0]) {
case NET_BPF_BUFSIZE:
newval = bpf_bufsize;
error = sysctl_int(oldp, oldlenp, newp, newlen, &newval);
if (error)
return (error);
if (newval < BPF_MINBUFSIZE || newval > bpf_maxbufsize)
return (EINVAL);
bpf_bufsize = newval;
break;
case NET_BPF_MAXBUFSIZE:
newval = bpf_maxbufsize;
error = sysctl_int(oldp, oldlenp, newp, newlen, &newval);
if (error)
return (error);
if (newval < BPF_MINBUFSIZE)
return (EINVAL);
bpf_maxbufsize = newval;
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
struct bpf_d *
bpfilter_lookup(int unit)
{
struct bpf_d *bd;
LIST_FOREACH(bd, &bpf_d_list, bd_list)
if (bd->bd_unit == unit)
return (bd);
return (NULL);
}
struct bpf_d *
bpfilter_create(int unit)
{
struct bpf_d *bd;
if ((bd = bpfilter_lookup(unit)) != NULL)
return (NULL);
if ((bd = malloc(sizeof(*bd), M_DEVBUF, M_NOWAIT|M_ZERO)) != NULL) {
bd->bd_unit = unit;
LIST_INSERT_HEAD(&bpf_d_list, bd, bd_list);
}
return (bd);
}
void
bpfilter_destroy(struct bpf_d *bd)
{
LIST_REMOVE(bd, bd_list);
free(bd, M_DEVBUF);
}
/*
* Get a list of available data link type of the interface.
*/
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));
if (error)
break;
}
n++;
}
bfl->bfl_len = n;
return (error);
}
/*
* Set the data link type of a BPF instance.
*/
int
bpf_setdlt(struct bpf_d *d, u_int dlt)
{
int s;
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();
bpf_detachd(d);
bpf_attachd(d, bp);
bpf_reset_d(d);
splx(s);
return (0);
}
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