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freebsd-skq/sys/net/bpf.c
Robert Watson a7a91e6592 Maintain and observe a ZBUF_FLAG_IMMUTABLE flag on zero-copy BPF 
buffer kernel descriptors, which is used to allow the buffer
currently in the BPF "store" position to be assigned to userspace
when it fills, even if userspace hasn't acknowledged the buffer
in the "hold" position yet.  To implement this, notify the buffer
model when a buffer becomes full, and check that the store buffer
is writable, not just for it being full, before trying to append
new packet data.  Shared memory buffers will be assigned to
userspace at most once per fill, be it in the store or in the
hold position.

This removes the restriction that at most one shared memory can
by owned by userspace, reducing the chances that userspace will
need to call select() after acknowledging one buffer in order to
wait for the next buffer when under high load.  This more fully
realizes the goal of zero system calls in order to process a
high-speed packet stream from BPF.

Update bpf.4 to reflect that both buffers may be owned by userspace
at once; caution against assuming this.
2008-04-07 02:51:00 +00:00

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/*-
* Copyright (c) 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from the Stanford/CMU enet packet filter,
* (net/enet.c) distributed as part of 4.3BSD, and code contributed
* to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
* Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)bpf.c 8.4 (Berkeley) 1/9/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bpf.h"
#include "opt_mac.h"
#include "opt_netgraph.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/uio.h>
#include <sys/event.h>
#include <sys/file.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/bpf.h>
#include <net/bpf_buffer.h>
#ifdef BPF_JITTER
#include <net/bpf_jitter.h>
#endif
#include <net/bpf_zerocopy.h>
#include <net/bpfdesc.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <net80211/ieee80211_freebsd.h>
#include <security/mac/mac_framework.h>
MALLOC_DEFINE(M_BPF, "BPF", "BPF data");
#if defined(DEV_BPF) || defined(NETGRAPH_BPF)
#define PRINET 26 /* interruptible */
#define M_SKIP_BPF M_SKIP_FIREWALL
/*
* bpf_iflist is a list of BPF interface structures, each corresponding to a
* specific DLT. The same network interface might have several BPF interface
* structures registered by different layers in the stack (i.e., 802.11
* frames, ethernet frames, etc).
*/
static LIST_HEAD(, bpf_if) bpf_iflist;
static struct mtx bpf_mtx; /* bpf global lock */
static int bpf_bpfd_cnt;
static void bpf_attachd(struct bpf_d *, struct bpf_if *);
static void bpf_detachd(struct bpf_d *);
static void bpf_freed(struct bpf_d *);
static int bpf_movein(struct uio *, int, struct ifnet *, struct mbuf **,
struct sockaddr *, int *, struct bpf_insn *);
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 (*)(struct bpf_d *, caddr_t, u_int, void *, u_int),
struct timeval *);
static void reset_d(struct bpf_d *);
static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd);
static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
static int bpf_setdlt(struct bpf_d *, u_int);
static void filt_bpfdetach(struct knote *);
static int filt_bpfread(struct knote *, long);
static void bpf_drvinit(void *);
static void bpf_clone(void *, struct ucred *, char *, int, struct cdev **);
static int bpf_stats_sysctl(SYSCTL_HANDLER_ARGS);
SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl");
static int bpf_maxinsns = BPF_MAXINSNS;
SYSCTL_INT(_net_bpf, OID_AUTO, maxinsns, CTLFLAG_RW,
&bpf_maxinsns, 0, "Maximum bpf program instructions");
static int bpf_zerocopy_enable = 0;
SYSCTL_INT(_net_bpf, OID_AUTO, zerocopy_enable, CTLFLAG_RW,
&bpf_zerocopy_enable, 0, "Enable new zero-copy BPF buffer sessions");
SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_RW,
bpf_stats_sysctl, "bpf statistics portal");
static d_open_t bpfopen;
static d_close_t bpfclose;
static d_read_t bpfread;
static d_write_t bpfwrite;
static d_ioctl_t bpfioctl;
static d_poll_t bpfpoll;
static d_kqfilter_t bpfkqfilter;
static struct cdevsw bpf_cdevsw = {
.d_version = D_VERSION,
.d_open = bpfopen,
.d_close = bpfclose,
.d_read = bpfread,
.d_write = bpfwrite,
.d_ioctl = bpfioctl,
.d_poll = bpfpoll,
.d_name = "bpf",
.d_kqfilter = bpfkqfilter,
};
static struct filterops bpfread_filtops =
{ 1, NULL, filt_bpfdetach, filt_bpfread };
/*
* Wrapper functions for various buffering methods. If the set of buffer
* modes expands, we will probably want to introduce a switch data structure
* similar to protosw, et.
*/
static void
bpf_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
u_int len)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
return (bpf_buffer_append_bytes(d, buf, offset, src, len));
case BPF_BUFMODE_ZBUF:
d->bd_zcopy++;
return (bpf_zerocopy_append_bytes(d, buf, offset, src, len));
default:
panic("bpf_buf_append_bytes");
}
}
static void
bpf_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
u_int len)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
return (bpf_buffer_append_mbuf(d, buf, offset, src, len));
case BPF_BUFMODE_ZBUF:
d->bd_zcopy++;
return (bpf_zerocopy_append_mbuf(d, buf, offset, src, len));
default:
panic("bpf_buf_append_mbuf");
}
}
/*
* If the buffer mechanism has a way to decide that a held buffer can be made
* free, then it is exposed via the bpf_canfreebuf() interface. (1) is
* returned if the buffer can be discarded, (0) is returned if it cannot.
*/
static int
bpf_canfreebuf(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_ZBUF:
return (bpf_zerocopy_canfreebuf(d));
}
return (0);
}
/*
* Allow the buffer model to indicate that the current store buffer is
* immutable, regardless of the appearance of space. Return (1) if the
* buffer is writable, and (0) if not.
*/
static int
bpf_canwritebuf(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_ZBUF:
return (bpf_zerocopy_canwritebuf(d));
}
return (1);
}
/*
* Notify buffer model that an attempt to write to the store buffer has
* resulted in a dropped packet, in which case the buffer may be considered
* full.
*/
static void
bpf_buffull(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_ZBUF:
bpf_zerocopy_buffull(d);
break;
}
}
/*
* Notify the buffer model that a buffer has moved into the hold position.
*/
void
bpf_bufheld(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_ZBUF:
bpf_zerocopy_bufheld(d);
break;
}
}
static void
bpf_free(struct bpf_d *d)
{
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
return (bpf_buffer_free(d));
case BPF_BUFMODE_ZBUF:
return (bpf_zerocopy_free(d));
default:
panic("bpf_buf_free");
}
}
static int
bpf_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio)
{
if (d->bd_bufmode != BPF_BUFMODE_BUFFER)
return (EOPNOTSUPP);
return (bpf_buffer_uiomove(d, buf, len, uio));
}
static int
bpf_ioctl_sblen(struct bpf_d *d, u_int *i)
{
if (d->bd_bufmode != BPF_BUFMODE_BUFFER)
return (EOPNOTSUPP);
return (bpf_buffer_ioctl_sblen(d, i));
}
static int
bpf_ioctl_getzmax(struct thread *td, struct bpf_d *d, size_t *i)
{
if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
return (EOPNOTSUPP);
return (bpf_zerocopy_ioctl_getzmax(td, d, i));
}
static int
bpf_ioctl_rotzbuf(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz)
{
if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
return (EOPNOTSUPP);
return (bpf_zerocopy_ioctl_rotzbuf(td, d, bz));
}
static int
bpf_ioctl_setzbuf(struct thread *td, struct bpf_d *d, struct bpf_zbuf *bz)
{
if (d->bd_bufmode != BPF_BUFMODE_ZBUF)
return (EOPNOTSUPP);
return (bpf_zerocopy_ioctl_setzbuf(td, d, bz));
}
/*
* General BPF functions.
*/
static int
bpf_movein(struct uio *uio, int linktype, struct ifnet *ifp, struct mbuf **mp,
struct sockaddr *sockp, int *hdrlen, struct bpf_insn *wfilter)
{
const struct ieee80211_bpf_params *p;
struct ether_header *eh;
struct mbuf *m;
int error;
int len;
int hlen;
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_EN10MB:
sockp->sa_family = AF_UNSPEC;
/* XXX Would MAXLINKHDR be better? */
hlen = ETHER_HDR_LEN;
break;
case DLT_FDDI:
sockp->sa_family = AF_IMPLINK;
hlen = 0;
break;
case DLT_RAW:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
break;
case DLT_NULL:
/*
* null interface types require a 4 byte pseudo header which
* corresponds to the address family of the packet.
*/
sockp->sa_family = AF_UNSPEC;
hlen = 4;
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;
case DLT_PPP:
sockp->sa_family = AF_UNSPEC;
hlen = 4; /* This should match PPP_HDRLEN */
break;
case DLT_IEEE802_11: /* IEEE 802.11 wireless */
sockp->sa_family = AF_IEEE80211;
hlen = 0;
break;
case DLT_IEEE802_11_RADIO: /* IEEE 802.11 wireless w/ phy params */
sockp->sa_family = AF_IEEE80211;
sockp->sa_len = 12; /* XXX != 0 */
hlen = sizeof(struct ieee80211_bpf_params);
break;
default:
return (EIO);
}
len = uio->uio_resid;
if (len - hlen > ifp->if_mtu)
return (EMSGSIZE);
if ((unsigned)len > MCLBYTES)
return (EIO);
if (len > MHLEN)
m = m_getcl(M_WAIT, MT_DATA, M_PKTHDR);
else
MGETHDR(m, M_WAIT, MT_DATA);
m->m_pkthdr.len = m->m_len = len;
m->m_pkthdr.rcvif = NULL;
*mp = m;
if (m->m_len < hlen) {
error = EPERM;
goto bad;
}
error = uiomove(mtod(m, u_char *), len, uio);
if (error)
goto bad;
slen = bpf_filter(wfilter, mtod(m, u_char *), len, len);
if (slen == 0) {
error = EPERM;
goto bad;
}
/* Check for multicast destination */
switch (linktype) {
case DLT_EN10MB:
eh = mtod(m, struct ether_header *);
if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost,
ETHER_ADDR_LEN) == 0)
m->m_flags |= M_BCAST;
else
m->m_flags |= M_MCAST;
}
break;
}
/*
* Make room for link header, and copy it to sockaddr
*/
if (hlen != 0) {
if (sockp->sa_family == AF_IEEE80211) {
/*
* Collect true length from the parameter header
* NB: sockp is known to be zero'd so if we do a
* short copy unspecified parameters will be
* zero.
* NB: packet may not be aligned after stripping
* bpf params
* XXX check ibp_vers
*/
p = mtod(m, const struct ieee80211_bpf_params *);
hlen = p->ibp_len;
if (hlen > sizeof(sockp->sa_data)) {
error = EINVAL;
goto bad;
}
}
bcopy(m->m_data, sockp->sa_data, hlen);
}
*hdrlen = hlen;
return (0);
bad:
m_freem(m);
return (error);
}
/*
* Attach file to the bpf interface, i.e. make d listen on bp.
*/
static 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.
*/
BPFIF_LOCK(bp);
d->bd_bif = bp;
LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
bpf_bpfd_cnt++;
BPFIF_UNLOCK(bp);
}
/*
* Detach a file from its interface.
*/
static void
bpf_detachd(struct bpf_d *d)
{
int error;
struct bpf_if *bp;
struct ifnet *ifp;
bp = d->bd_bif;
BPFIF_LOCK(bp);
BPFD_LOCK(d);
ifp = d->bd_bif->bif_ifp;
/*
* Remove d from the interface's descriptor list.
*/
LIST_REMOVE(d, bd_next);
bpf_bpfd_cnt--;
d->bd_bif = NULL;
BPFD_UNLOCK(d);
BPFIF_UNLOCK(bp);
/*
* Check if this descriptor had requested promiscuous mode.
* If so, turn it off.
*/
if (d->bd_promisc) {
d->bd_promisc = 0;
error = ifpromisc(ifp, 0);
if (error != 0 && error != ENXIO) {
/*
* ENXIO can happen if a pccard is unplugged
* Something is really wrong if we were able to put
* the driver into promiscuous mode, but can't
* take it out.
*/
if_printf(bp->bif_ifp,
"bpf_detach: ifpromisc failed (%d)\n", error);
}
}
}
/*
* Open ethernet device. Returns ENXIO for illegal minor device number,
* EBUSY if file is open by another process.
*/
/* ARGSUSED */
static int
bpfopen(struct cdev *dev, int flags, int fmt, struct thread *td)
{
struct bpf_d *d;
mtx_lock(&bpf_mtx);
d = dev->si_drv1;
/*
* Each minor can be opened by only one process. If the requested
* minor is in use, return EBUSY.
*/
if (d != NULL) {
mtx_unlock(&bpf_mtx);
return (EBUSY);
}
dev->si_drv1 = (struct bpf_d *)~0; /* mark device in use */
mtx_unlock(&bpf_mtx);
if ((dev->si_flags & SI_NAMED) == 0)
make_dev(&bpf_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600,
"bpf%d", dev2unit(dev));
MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK | M_ZERO);
dev->si_drv1 = d;
/*
* For historical reasons, perform a one-time initialization call to
* the buffer routines, even though we're not yet committed to a
* particular buffer method.
*/
bpf_buffer_init(d);
d->bd_bufmode = BPF_BUFMODE_BUFFER;
d->bd_sig = SIGIO;
d->bd_direction = BPF_D_INOUT;
d->bd_pid = td->td_proc->p_pid;
#ifdef MAC
mac_bpfdesc_init(d);
mac_bpfdesc_create(td->td_ucred, d);
#endif
mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF);
callout_init(&d->bd_callout, CALLOUT_MPSAFE);
knlist_init(&d->bd_sel.si_note, &d->bd_mtx, NULL, NULL, NULL);
return (0);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
static int
bpfclose(struct cdev *dev, int flags, int fmt, struct thread *td)
{
struct bpf_d *d = dev->si_drv1;
BPFD_LOCK(d);
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
BPFD_UNLOCK(d);
funsetown(&d->bd_sigio);
mtx_lock(&bpf_mtx);
if (d->bd_bif)
bpf_detachd(d);
mtx_unlock(&bpf_mtx);
selwakeuppri(&d->bd_sel, PRINET);
#ifdef MAC
mac_bpfdesc_destroy(d);
#endif /* MAC */
knlist_destroy(&d->bd_sel.si_note);
bpf_freed(d);
dev->si_drv1 = NULL;
free(d, M_BPF);
return (0);
}
/*
* bpfread - read next chunk of packets from buffers
*/
static int
bpfread(struct cdev *dev, struct uio *uio, int ioflag)
{
struct bpf_d *d = dev->si_drv1;
int timed_out;
int error;
/*
* Restrict application to use a buffer the same size as
* as kernel buffers.
*/
if (uio->uio_resid != d->bd_bufsize)
return (EINVAL);
BPFD_LOCK(d);
d->bd_pid = curthread->td_proc->p_pid;
if (d->bd_bufmode != BPF_BUFMODE_BUFFER) {
BPFD_UNLOCK(d);
return (EOPNOTSUPP);
}
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 == NULL) {
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;
}
/*
* No data is available, check to see if the bpf device
* is still pointed at a real interface. If not, return
* ENXIO so that the userland process knows to rebind
* it before using it again.
*/
if (d->bd_bif == NULL) {
BPFD_UNLOCK(d);
return (ENXIO);
}
if (ioflag & O_NONBLOCK) {
BPFD_UNLOCK(d);
return (EWOULDBLOCK);
}
error = msleep(d, &d->bd_mtx, PRINET|PCATCH,
"bpf", d->bd_rtout);
if (error == EINTR || error == ERESTART) {
BPFD_UNLOCK(d);
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) {
BPFD_UNLOCK(d);
return (0);
}
ROTATE_BUFFERS(d);
break;
}
}
/*
* At this point, we know we have something in the hold slot.
*/
BPFD_UNLOCK(d);
/*
* 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.
*
* XXXRW: More synchronization needed here: what if a second thread
* issues a read on the same fd at the same time? Don't want this
* getting invalidated.
*/
error = bpf_uiomove(d, d->bd_hbuf, d->bd_hlen, uio);
BPFD_LOCK(d);
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
d->bd_hlen = 0;
BPFD_UNLOCK(d);
return (error);
}
/*
* If there are processes sleeping on this descriptor, wake them up.
*/
static __inline void
bpf_wakeup(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
if (d->bd_state == BPF_WAITING) {
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
}
wakeup(d);
if (d->bd_async && d->bd_sig && d->bd_sigio)
pgsigio(&d->bd_sigio, d->bd_sig, 0);
selwakeuppri(&d->bd_sel, PRINET);
KNOTE_LOCKED(&d->bd_sel.si_note, 0);
}
static void
bpf_timed_out(void *arg)
{
struct bpf_d *d = (struct bpf_d *)arg;
BPFD_LOCK(d);
if (d->bd_state == BPF_WAITING) {
d->bd_state = BPF_TIMED_OUT;
if (d->bd_slen != 0)
bpf_wakeup(d);
}
BPFD_UNLOCK(d);
}
static int
bpf_ready(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
if (!bpf_canfreebuf(d) && d->bd_hlen != 0)
return (1);
if ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
d->bd_slen != 0)
return (1);
return (0);
}
static int
bpfwrite(struct cdev *dev, struct uio *uio, int ioflag)
{
struct bpf_d *d = dev->si_drv1;
struct ifnet *ifp;
struct mbuf *m, *mc;
struct sockaddr dst;
int error, hlen;
d->bd_pid = curthread->td_proc->p_pid;
d->bd_wcount++;
if (d->bd_bif == NULL) {
d->bd_wdcount++;
return (ENXIO);
}
ifp = d->bd_bif->bif_ifp;
if ((ifp->if_flags & IFF_UP) == 0) {
d->bd_wdcount++;
return (ENETDOWN);
}
if (uio->uio_resid == 0) {
d->bd_wdcount++;
return (0);
}
bzero(&dst, sizeof(dst));
m = NULL;
hlen = 0;
error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp,
&m, &dst, &hlen, d->bd_wfilter);
if (error) {
d->bd_wdcount++;
return (error);
}
d->bd_wfcount++;
if (d->bd_hdrcmplt)
dst.sa_family = pseudo_AF_HDRCMPLT;
if (d->bd_feedback) {
mc = m_dup(m, M_DONTWAIT);
if (mc != NULL)
mc->m_pkthdr.rcvif = ifp;
/* XXX Do not return the same packet twice. */
if (d->bd_direction == BPF_D_INOUT)
m->m_flags |= M_SKIP_BPF;
} else
mc = NULL;
m->m_pkthdr.len -= hlen;
m->m_len -= hlen;
m->m_data += hlen; /* XXX */
#ifdef MAC
BPFD_LOCK(d);
mac_bpfdesc_create_mbuf(d, m);
if (mc != NULL)
mac_bpfdesc_create_mbuf(d, mc);
BPFD_UNLOCK(d);
#endif
error = (*ifp->if_output)(ifp, m, &dst, NULL);
if (error)
d->bd_wdcount++;
if (mc != NULL) {
if (error == 0)
(*ifp->if_input)(ifp, mc);
else
m_freem(mc);
}
return (error);
}
/*
* Reset a descriptor by flushing its packet buffer and clearing the
* receive and drop counts.
*/
static void
reset_d(struct bpf_d *d)
{
mtx_assert(&d->bd_mtx, MA_OWNED);
if (d->bd_hbuf) {
/* Free the hold buffer. */
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
}
d->bd_slen = 0;
d->bd_hlen = 0;
d->bd_rcount = 0;
d->bd_dcount = 0;
d->bd_fcount = 0;
d->bd_wcount = 0;
d->bd_wfcount = 0;
d->bd_wdcount = 0;
d->bd_zcopy = 0;
}
/*
* FIONREAD Check for read packet available.
* SIOCGIFADDR Get interface address - convenient hook to driver.
* BIOCGBLEN Get buffer len [for read()].
* BIOCSETF Set ethernet read filter.
* BIOCSETWF Set ethernet write 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.
* BIOCGHDRCMPLT Get "header already complete" flag
* BIOCSHDRCMPLT Set "header already complete" flag
* BIOCGDIRECTION Get packet direction flag
* BIOCSDIRECTION Set packet direction flag
* BIOCLOCK Set "locked" flag
* BIOCFEEDBACK Set packet feedback mode.
* BIOCSETZBUF Set current zero-copy buffer locations.
* BIOCGETZMAX Get maximum zero-copy buffer size.
* BIOCROTZBUF Force rotation of zero-copy buffer
* BIOCSETBUFMODE Set buffer mode.
* BIOCGETBUFMODE Get current buffer mode.
*/
/* ARGSUSED */
static int
bpfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
struct thread *td)
{
struct bpf_d *d = dev->si_drv1;
int error = 0;
/*
* Refresh PID associated with this descriptor.
*/
BPFD_LOCK(d);
d->bd_pid = td->td_proc->p_pid;
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
BPFD_UNLOCK(d);
if (d->bd_locked == 1) {
switch (cmd) {
case BIOCGBLEN:
case BIOCFLUSH:
case BIOCGDLT:
case BIOCGDLTLIST:
case BIOCGETIF:
case BIOCGRTIMEOUT:
case BIOCGSTATS:
case BIOCVERSION:
case BIOCGRSIG:
case BIOCGHDRCMPLT:
case BIOCFEEDBACK:
case FIONREAD:
case BIOCLOCK:
case BIOCSRTIMEOUT:
case BIOCIMMEDIATE:
case TIOCGPGRP:
case BIOCROTZBUF:
break;
default:
return (EPERM);
}
}
switch (cmd) {
default:
error = EINVAL;
break;
/*
* Check for read packet available.
*/
case FIONREAD:
{
int n;
BPFD_LOCK(d);
n = d->bd_slen;
if (d->bd_hbuf)
n += d->bd_hlen;
BPFD_UNLOCK(d);
*(int *)addr = n;
break;
}
case SIOCGIFADDR:
{
struct ifnet *ifp;
if (d->bd_bif == NULL)
error = EINVAL;
else {
ifp = d->bd_bif->bif_ifp;
error = (*ifp->if_ioctl)(ifp, cmd, addr);
}
break;
}
/*
* Get buffer len [for read()].
*/
case BIOCGBLEN:
*(u_int *)addr = d->bd_bufsize;
break;
/*
* Set buffer length.
*/
case BIOCSBLEN:
error = bpf_ioctl_sblen(d, (u_int *)addr);
break;
/*
* Set link layer read filter.
*/
case BIOCSETF:
case BIOCSETWF:
error = bpf_setf(d, (struct bpf_program *)addr, cmd);
break;
/*
* Flush read packet buffer.
*/
case BIOCFLUSH:
BPFD_LOCK(d);
reset_d(d);
BPFD_UNLOCK(d);
break;
/*
* Put interface into promiscuous mode.
*/
case BIOCPROMISC:
if (d->bd_bif == NULL) {
/*
* No interface attached yet.
*/
error = EINVAL;
break;
}
if (d->bd_promisc == 0) {
error = ifpromisc(d->bd_bif->bif_ifp, 1);
if (error == 0)
d->bd_promisc = 1;
}
break;
/*
* Get current data link type.
*/
case BIOCGDLT:
if (d->bd_bif == NULL)
error = EINVAL;
else
*(u_int *)addr = d->bd_bif->bif_dlt;
break;
/*
* Get a list of supported data link types.
*/
case BIOCGDLTLIST:
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_getdltlist(d, (struct bpf_dltlist *)addr);
break;
/*
* Set data link type.
*/
case BIOCSDLT:
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_setdlt(d, *(u_int *)addr);
break;
/*
* Get interface name.
*/
case BIOCGETIF:
if (d->bd_bif == NULL)
error = EINVAL;
else {
struct ifnet *const ifp = d->bd_bif->bif_ifp;
struct ifreq *const ifr = (struct ifreq *)addr;
strlcpy(ifr->ifr_name, ifp->if_xname,
sizeof(ifr->ifr_name));
}
break;
/*
* Set interface.
*/
case BIOCSETIF:
error = bpf_setif(d, (struct ifreq *)addr);
break;
/*
* Set read timeout.
*/
case BIOCSRTIMEOUT:
{
struct timeval *tv = (struct timeval *)addr;
/*
* Subtract 1 tick from tvtohz() since this isn't
* a one-shot timer.
*/
if ((error = itimerfix(tv)) == 0)
d->bd_rtout = tvtohz(tv) - 1;
break;
}
/*
* Get read timeout.
*/
case BIOCGRTIMEOUT:
{
struct timeval *tv = (struct timeval *)addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
break;
}
/*
* Get packet stats.
*/
case BIOCGSTATS:
{
struct bpf_stat *bs = (struct bpf_stat *)addr;
/* XXXCSJP overflow */
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;
}
/*
* Get "header already complete" flag
*/
case BIOCGHDRCMPLT:
*(u_int *)addr = d->bd_hdrcmplt;
break;
/*
* Set "header already complete" flag
*/
case BIOCSHDRCMPLT:
d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
break;
/*
* Get packet direction flag
*/
case BIOCGDIRECTION:
*(u_int *)addr = d->bd_direction;
break;
/*
* Set packet direction flag
*/
case BIOCSDIRECTION:
{
u_int direction;
direction = *(u_int *)addr;
switch (direction) {
case BPF_D_IN:
case BPF_D_INOUT:
case BPF_D_OUT:
d->bd_direction = direction;
break;
default:
error = EINVAL;
}
}
break;
case BIOCFEEDBACK:
d->bd_feedback = *(u_int *)addr;
break;
case BIOCLOCK:
d->bd_locked = 1;
break;
case FIONBIO: /* Non-blocking I/O */
break;
case FIOASYNC: /* Send signal on receive packets */
d->bd_async = *(int *)addr;
break;
case FIOSETOWN:
error = fsetown(*(int *)addr, &d->bd_sigio);
break;
case FIOGETOWN:
*(int *)addr = fgetown(&d->bd_sigio);
break;
/* This is deprecated, FIOSETOWN should be used instead. */
case TIOCSPGRP:
error = fsetown(-(*(int *)addr), &d->bd_sigio);
break;
/* This is deprecated, FIOGETOWN should be used instead. */
case TIOCGPGRP:
*(int *)addr = -fgetown(&d->bd_sigio);
break;
case BIOCSRSIG: /* Set receive signal */
{
u_int sig;
sig = *(u_int *)addr;
if (sig >= NSIG)
error = EINVAL;
else
d->bd_sig = sig;
break;
}
case BIOCGRSIG:
*(u_int *)addr = d->bd_sig;
break;
case BIOCGETBUFMODE:
*(u_int *)addr = d->bd_bufmode;
break;
case BIOCSETBUFMODE:
/*
* Allow the buffering mode to be changed as long as we
* haven't yet committed to a particular mode. Our
* definition of commitment, for now, is whether or not a
* buffer has been allocated or an interface attached, since
* that's the point where things get tricky.
*/
switch (*(u_int *)addr) {
case BPF_BUFMODE_BUFFER:
break;
case BPF_BUFMODE_ZBUF:
if (bpf_zerocopy_enable)
break;
/* FALLSTHROUGH */
default:
return (EINVAL);
}
BPFD_LOCK(d);
if (d->bd_sbuf != NULL || d->bd_hbuf != NULL ||
d->bd_fbuf != NULL || d->bd_bif != NULL) {
BPFD_UNLOCK(d);
return (EBUSY);
}
d->bd_bufmode = *(u_int *)addr;
BPFD_UNLOCK(d);
break;
case BIOCGETZMAX:
return (bpf_ioctl_getzmax(td, d, (size_t *)addr));
case BIOCSETZBUF:
return (bpf_ioctl_setzbuf(td, d, (struct bpf_zbuf *)addr));
case BIOCROTZBUF:
return (bpf_ioctl_rotzbuf(td, d, (struct bpf_zbuf *)addr));
}
return (error);
}
/*
* Set d's packet filter program to fp. If this file already has a filter,
* free it and replace it. Returns EINVAL for bogus requests.
*/
static int
bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
{
struct bpf_insn *fcode, *old;
u_int wfilter, flen, size;
#ifdef BPF_JITTER
bpf_jit_filter *ofunc;
#endif
if (cmd == BIOCSETWF) {
old = d->bd_wfilter;
wfilter = 1;
#ifdef BPF_JITTER
ofunc = NULL;
#endif
} else {
wfilter = 0;
old = d->bd_rfilter;
#ifdef BPF_JITTER
ofunc = d->bd_bfilter;
#endif
}
if (fp->bf_insns == NULL) {
if (fp->bf_len != 0)
return (EINVAL);
BPFD_LOCK(d);
if (wfilter)
d->bd_wfilter = NULL;
else {
d->bd_rfilter = NULL;
#ifdef BPF_JITTER
d->bd_bfilter = NULL;
#endif
}
reset_d(d);
BPFD_UNLOCK(d);
if (old != NULL)
free((caddr_t)old, M_BPF);
#ifdef BPF_JITTER
if (ofunc != NULL)
bpf_destroy_jit_filter(ofunc);
#endif
return (0);
}
flen = fp->bf_len;
if (flen > bpf_maxinsns)
return (EINVAL);
size = flen * sizeof(*fp->bf_insns);
fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK);
if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 &&
bpf_validate(fcode, (int)flen)) {
BPFD_LOCK(d);
if (wfilter)
d->bd_wfilter = fcode;
else {
d->bd_rfilter = fcode;
#ifdef BPF_JITTER
d->bd_bfilter = bpf_jitter(fcode, flen);
#endif
}
reset_d(d);
BPFD_UNLOCK(d);
if (old != NULL)
free((caddr_t)old, M_BPF);
#ifdef BPF_JITTER
if (ofunc != NULL)
bpf_destroy_jit_filter(ofunc);
#endif
return (0);
}
free((caddr_t)fcode, M_BPF);
return (EINVAL);
}
/*
* Detach a file from its current interface (if attached at all) and attach
* to the interface indicated by the name stored in ifr.
* Return an errno or 0.
*/
static int
bpf_setif(struct bpf_d *d, struct ifreq *ifr)
{
struct bpf_if *bp;
struct ifnet *theywant;
theywant = ifunit(ifr->ifr_name);
if (theywant == NULL || theywant->if_bpf == NULL)
return (ENXIO);
bp = theywant->if_bpf;
/*
* Behavior here depends on the buffering model. If we're using
* kernel memory buffers, then we can allocate them here. If we're
* using zero-copy, then the user process must have registered
* buffers by the time we get here. If not, return an error.
*
* XXXRW: There are locking issues here with multi-threaded use: what
* if two threads try to set the interface at once?
*/
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
if (d->bd_sbuf == NULL)
bpf_buffer_alloc(d);
KASSERT(d->bd_sbuf != NULL, ("bpf_setif: bd_sbuf NULL"));
break;
case BPF_BUFMODE_ZBUF:
if (d->bd_sbuf == NULL)
return (EINVAL);
break;
default:
panic("bpf_setif: bufmode %d", d->bd_bufmode);
}
if (bp != d->bd_bif) {
if (d->bd_bif)
/*
* Detach if attached to something else.
*/
bpf_detachd(d);
bpf_attachd(d, bp);
}
BPFD_LOCK(d);
reset_d(d);
BPFD_UNLOCK(d);
return (0);
}
/*
* Support for select() and poll() system calls
*
* Return true iff the specific operation will not block indefinitely.
* Otherwise, return false but make a note that a selwakeup() must be done.
*/
static int
bpfpoll(struct cdev *dev, int events, struct thread *td)
{
struct bpf_d *d;
int revents;
d = dev->si_drv1;
if (d->bd_bif == NULL)
return (ENXIO);
/*
* Refresh PID associated with this descriptor.
*/
revents = events & (POLLOUT | POLLWRNORM);
BPFD_LOCK(d);
d->bd_pid = td->td_proc->p_pid;
if (events & (POLLIN | POLLRDNORM)) {
if (bpf_ready(d))
revents |= events & (POLLIN | POLLRDNORM);
else {
selrecord(td, &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;
}
}
}
BPFD_UNLOCK(d);
return (revents);
}
/*
* Support for kevent() system call. Register EVFILT_READ filters and
* reject all others.
*/
int
bpfkqfilter(struct cdev *dev, struct knote *kn)
{
struct bpf_d *d = (struct bpf_d *)dev->si_drv1;
if (kn->kn_filter != EVFILT_READ)
return (1);
/*
* Refresh PID associated with this descriptor.
*/
BPFD_LOCK(d);
d->bd_pid = curthread->td_proc->p_pid;
kn->kn_fop = &bpfread_filtops;
kn->kn_hook = d;
knlist_add(&d->bd_sel.si_note, kn, 1);
BPFD_UNLOCK(d);
return (0);
}
static void
filt_bpfdetach(struct knote *kn)
{
struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
knlist_remove(&d->bd_sel.si_note, kn, 0);
}
static int
filt_bpfread(struct knote *kn, long hint)
{
struct bpf_d *d = (struct bpf_d *)kn->kn_hook;
int ready;
BPFD_LOCK_ASSERT(d);
ready = bpf_ready(d);
if (ready) {
kn->kn_data = d->bd_slen;
if (d->bd_hbuf)
kn->kn_data += d->bd_hlen;
}
else 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;
}
return (ready);
}
/*
* 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(struct bpf_if *bp, u_char *pkt, u_int pktlen)
{
struct bpf_d *d;
u_int slen;
int gottime;
struct timeval tv;
gottime = 0;
BPFIF_LOCK(bp);
LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
BPFD_LOCK(d);
++d->bd_rcount;
#ifdef BPF_JITTER
if (bpf_jitter_enable != 0 && d->bd_bfilter != NULL)
slen = (*(d->bd_bfilter->func))(pkt, pktlen, pktlen);
else
#endif
slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
if (slen != 0) {
d->bd_fcount++;
if (!gottime) {
microtime(&tv);
gottime = 1;
}
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, pkt, pktlen, slen,
bpf_append_bytes, &tv);
}
BPFD_UNLOCK(d);
}
BPFIF_UNLOCK(bp);
}
#define BPF_CHECK_DIRECTION(d, m) \
if (((d)->bd_direction == BPF_D_IN && (m)->m_pkthdr.rcvif == NULL) || \
((d)->bd_direction == BPF_D_OUT && (m)->m_pkthdr.rcvif != NULL))
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
*/
void
bpf_mtap(struct bpf_if *bp, struct mbuf *m)
{
struct bpf_d *d;
u_int pktlen, slen;
int gottime;
struct timeval tv;
if (m->m_flags & M_SKIP_BPF) {
m->m_flags &= ~M_SKIP_BPF;
return;
}
gottime = 0;
pktlen = m_length(m, NULL);
BPFIF_LOCK(bp);
LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
BPF_CHECK_DIRECTION(d, m)
continue;
BPFD_LOCK(d);
++d->bd_rcount;
#ifdef BPF_JITTER
/* XXX We cannot handle multiple mbufs. */
if (bpf_jitter_enable != 0 && d->bd_bfilter != NULL &&
m->m_next == NULL)
slen = (*(d->bd_bfilter->func))(mtod(m, u_char *),
pktlen, pktlen);
else
#endif
slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
if (slen != 0) {
d->bd_fcount++;
if (!gottime) {
microtime(&tv);
gottime = 1;
}
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, (u_char *)m, pktlen, slen,
bpf_append_mbuf, &tv);
}
BPFD_UNLOCK(d);
}
BPFIF_UNLOCK(bp);
}
/*
* Incoming linkage from device drivers, when packet is in
* an mbuf chain and to be prepended by a contiguous header.
*/
void
bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m)
{
struct mbuf mb;
struct bpf_d *d;
u_int pktlen, slen;
int gottime;
struct timeval tv;
if (m->m_flags & M_SKIP_BPF) {
m->m_flags &= ~M_SKIP_BPF;
return;
}
gottime = 0;
pktlen = m_length(m, NULL);
/*
* 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.
*/
mb.m_next = m;
mb.m_data = data;
mb.m_len = dlen;
pktlen += dlen;
BPFIF_LOCK(bp);
LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
BPF_CHECK_DIRECTION(d, m)
continue;
BPFD_LOCK(d);
++d->bd_rcount;
slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0);
if (slen != 0) {
d->bd_fcount++;
if (!gottime) {
microtime(&tv);
gottime = 1;
}
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, (u_char *)&mb, pktlen, slen,
bpf_append_mbuf, &tv);
}
BPFD_UNLOCK(d);
}
BPFIF_UNLOCK(bp);
}
#undef BPF_CHECK_DIRECTION
/*
* Move the packet data from interface memory (pkt) into the
* store buffer. "cpfn" is the routine called to do the actual data
* transfer. bcopy is passed in to copy contiguous chunks, while
* bpf_append_mbuf 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)(struct bpf_d *, caddr_t, u_int, void *, u_int),
struct timeval *tv)
{
struct bpf_hdr hdr;
int totlen, curlen;
int hdrlen = d->bd_bif->bif_hdrlen;
int do_wakeup = 0;
BPFD_LOCK_ASSERT(d);
/*
* Detect whether user space has released a buffer back to us, and if
* so, move it from being a hold buffer to a free buffer. This may
* not be the best place to do it (for example, we might only want to
* run this check if we need the space), but for now it's a reliable
* spot to do it.
*/
if (d->bd_fbuf == NULL && bpf_canfreebuf(d)) {
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
d->bd_hlen = 0;
}
/*
* 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.
*
* Drop the packet if there's no room and no hope of room
* If the packet would overflow the storage buffer or the storage
* buffer is considered immutable by the buffer model, try to rotate
* the buffer and wakeup pending processes.
*/
curlen = BPF_WORDALIGN(d->bd_slen);
if (curlen + totlen > d->bd_bufsize || !bpf_canwritebuf(d)) {
if (d->bd_fbuf == NULL) {
/*
* There's no room in the store buffer, and no
* prospect of room, so drop the packet. Notify the
* buffer model.
*/
bpf_buffull(d);
++d->bd_dcount;
return;
}
ROTATE_BUFFERS(d);
do_wakeup = 1;
curlen = 0;
} else 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.
*/
do_wakeup = 1;
/*
* Append the bpf header. Note we append the actual header size, but
* move forward the length of the header plus padding.
*/
bzero(&hdr, sizeof(hdr));
hdr.bh_tstamp = *tv;
hdr.bh_datalen = pktlen;
hdr.bh_hdrlen = hdrlen;
hdr.bh_caplen = totlen - hdrlen;
bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr, sizeof(hdr));
/*
* Copy the packet data into the store buffer and update its length.
*/
(*cpfn)(d, d->bd_sbuf, curlen + hdrlen, pkt, hdr.bh_caplen);
d->bd_slen = curlen + totlen;
if (do_wakeup)
bpf_wakeup(d);
}
/*
* 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.
*/
bpf_free(d);
if (d->bd_rfilter) {
free((caddr_t)d->bd_rfilter, M_BPF);
#ifdef BPF_JITTER
bpf_destroy_jit_filter(d->bd_bfilter);
#endif
}
if (d->bd_wfilter)
free((caddr_t)d->bd_wfilter, M_BPF);
mtx_destroy(&d->bd_mtx);
}
/*
* 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 an interface to bpf. ifp is a pointer to the structure
* defining the interface to be attached, dlt is the link layer type,
* and hdrlen is the fixed size of the link header (variable length
* headers are not yet supporrted).
*/
void
bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
{
struct bpf_if *bp;
bp = malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO);
if (bp == NULL)
panic("bpfattach");
LIST_INIT(&bp->bif_dlist);
bp->bif_ifp = ifp;
bp->bif_dlt = dlt;
mtx_init(&bp->bif_mtx, "bpf interface lock", NULL, MTX_DEF);
KASSERT(*driverp == NULL, ("bpfattach2: driverp already initialized"));
*driverp = bp;
mtx_lock(&bpf_mtx);
LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next);
mtx_unlock(&bpf_mtx);
/*
* Compute the length of the bpf header. This is not necessarily
* equal to SIZEOF_BPF_HDR because we want to insert spacing such
* that the network layer header begins on a longword boundary (for
* performance reasons and to alleviate alignment restrictions).
*/
bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen;
if (bootverbose)
if_printf(ifp, "bpf attached\n");
}
/*
* Detach bpf from an interface. This involves detaching each descriptor
* associated with the interface, and leaving bd_bif NULL. Notify each
* descriptor as it's detached so that any sleepers wake up and get
* ENXIO.
*/
void
bpfdetach(struct ifnet *ifp)
{
struct bpf_if *bp;
struct bpf_d *d;
/* Locate BPF interface information */
mtx_lock(&bpf_mtx);
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (ifp == bp->bif_ifp)
break;
}
/* Interface wasn't attached */
if ((bp == NULL) || (bp->bif_ifp == NULL)) {
mtx_unlock(&bpf_mtx);
printf("bpfdetach: %s was not attached\n", ifp->if_xname);
return;
}
LIST_REMOVE(bp, bif_next);
mtx_unlock(&bpf_mtx);
while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
bpf_detachd(d);
BPFD_LOCK(d);
bpf_wakeup(d);
BPFD_UNLOCK(d);
}
mtx_destroy(&bp->bif_mtx);
free(bp, M_BPF);
}
/*
* 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;
mtx_lock(&bpf_mtx);
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp != ifp)
continue;
if (bfl->bfl_list != NULL) {
if (n >= bfl->bfl_len) {
mtx_unlock(&bpf_mtx);
return (ENOMEM);
}
error = copyout(&bp->bif_dlt,
bfl->bfl_list + n, sizeof(u_int));
}
n++;
}
mtx_unlock(&bpf_mtx);
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 error, opromisc;
struct ifnet *ifp;
struct bpf_if *bp;
if (d->bd_bif->bif_dlt == dlt)
return (0);
ifp = d->bd_bif->bif_ifp;
mtx_lock(&bpf_mtx);
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
break;
}
mtx_unlock(&bpf_mtx);
if (bp != NULL) {
opromisc = d->bd_promisc;
bpf_detachd(d);
bpf_attachd(d, bp);
BPFD_LOCK(d);
reset_d(d);
BPFD_UNLOCK(d);
if (opromisc) {
error = ifpromisc(bp->bif_ifp, 1);
if (error)
if_printf(bp->bif_ifp,
"bpf_setdlt: ifpromisc failed (%d)\n",
error);
else
d->bd_promisc = 1;
}
}
return (bp == NULL ? EINVAL : 0);
}
static void
bpf_clone(void *arg, struct ucred *cred, char *name, int namelen,
struct cdev **dev)
{
int u;
if (*dev != NULL)
return;
if (dev_stdclone(name, NULL, "bpf", &u) != 1)
return;
*dev = make_dev(&bpf_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600,
"bpf%d", u);
dev_ref(*dev);
(*dev)->si_flags |= SI_CHEAPCLONE;
return;
}
static void
bpf_drvinit(void *unused)
{
mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF);
LIST_INIT(&bpf_iflist);
EVENTHANDLER_REGISTER(dev_clone, bpf_clone, 0, 1000);
}
static void
bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd)
{
bzero(d, sizeof(*d));
BPFD_LOCK_ASSERT(bd);
d->bd_structsize = sizeof(*d);
d->bd_immediate = bd->bd_immediate;
d->bd_promisc = bd->bd_promisc;
d->bd_hdrcmplt = bd->bd_hdrcmplt;
d->bd_direction = bd->bd_direction;
d->bd_feedback = bd->bd_feedback;
d->bd_async = bd->bd_async;
d->bd_rcount = bd->bd_rcount;
d->bd_dcount = bd->bd_dcount;
d->bd_fcount = bd->bd_fcount;
d->bd_sig = bd->bd_sig;
d->bd_slen = bd->bd_slen;
d->bd_hlen = bd->bd_hlen;
d->bd_bufsize = bd->bd_bufsize;
d->bd_pid = bd->bd_pid;
strlcpy(d->bd_ifname,
bd->bd_bif->bif_ifp->if_xname, IFNAMSIZ);
d->bd_locked = bd->bd_locked;
d->bd_wcount = bd->bd_wcount;
d->bd_wdcount = bd->bd_wdcount;
d->bd_wfcount = bd->bd_wfcount;
d->bd_zcopy = bd->bd_zcopy;
d->bd_bufmode = bd->bd_bufmode;
}
static int
bpf_stats_sysctl(SYSCTL_HANDLER_ARGS)
{
struct xbpf_d *xbdbuf, *xbd;
int index, error;
struct bpf_if *bp;
struct bpf_d *bd;
/*
* XXX This is not technically correct. It is possible for non
* privileged users to open bpf devices. It would make sense
* if the users who opened the devices were able to retrieve
* the statistics for them, too.
*/
error = priv_check(req->td, PRIV_NET_BPF);
if (error)
return (error);
if (req->oldptr == NULL)
return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd)));
if (bpf_bpfd_cnt == 0)
return (SYSCTL_OUT(req, 0, 0));
xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK);
mtx_lock(&bpf_mtx);
if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) {
mtx_unlock(&bpf_mtx);
free(xbdbuf, M_BPF);
return (ENOMEM);
}
index = 0;
LIST_FOREACH(bp, &bpf_iflist, bif_next) {
BPFIF_LOCK(bp);
LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
xbd = &xbdbuf[index++];
BPFD_LOCK(bd);
bpfstats_fill_xbpf(xbd, bd);
BPFD_UNLOCK(bd);
}
BPFIF_UNLOCK(bp);
}
mtx_unlock(&bpf_mtx);
error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd));
free(xbdbuf, M_BPF);
return (error);
}
SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,bpf_drvinit,NULL);
#else /* !DEV_BPF && !NETGRAPH_BPF */
/*
* NOP stubs to allow bpf-using drivers to load and function.
*
* A 'better' implementation would allow the core bpf functionality
* to be loaded at runtime.
*/
static struct bpf_if bp_null;
void
bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
{
}
void
bpf_mtap(struct bpf_if *bp, struct mbuf *m)
{
}
void
bpf_mtap2(struct bpf_if *bp, void *d, u_int l, struct mbuf *m)
{
}
void
bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
{
bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf);
}
void
bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
{
*driverp = &bp_null;
}
void
bpfdetach(struct ifnet *ifp)
{
}
u_int
bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
{
return -1; /* "no filter" behaviour */
}
int
bpf_validate(const struct bpf_insn *f, int len)
{
return 0; /* false */
}
#endif /* !DEV_BPF && !NETGRAPH_BPF */
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