<commit_before>/*
 * 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 <NAME> and <NAME> 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
 *
 * $FreeBSD$
 */

#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/mac.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/filedesc.h>

#include <sys/event.h>
#include <sys/file.h>
#include <sys/poll.h>
#include <sys/proc.h>

#include <sys/socket.h>
#include <sys/vnode.h>

#include <net/if.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

static MALLOC_DEFINE(M_BPF, "BPF", "BPF data");

#if defined(DEV_BPF) || defined(NETGRAPH_BPF)

#define PRINET  26			/* interruptible */

/*
 * The default read buffer size is patchable.
 */
static int bpf_bufsize = 4096;
SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
	&bpf_bufsize, 0, "");
static int bpf_maxbufsize = BPF_MAXBUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
	&bpf_maxbufsize, 0, "");

/*
 *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
 */
static struct bpf_if	*bpf_iflist;
static struct mtx	bpf_mtx;		/* bpf global lock */

static int	bpf_allocbufs(struct bpf_d *);
static void	bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
static void	bpf_detachd(struct bpf_d *d);
static void	bpf_freed(struct bpf_d *);
static void	bpf_mcopy(const void *, void *, size_t);
static int	bpf_movein(struct uio *, int,
		    struct mbuf **, struct sockaddr *, int *);
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 (*)(const void *, void *, size_t));
static void	reset_d(struct bpf_d *);
static int	 bpf_setf(struct bpf_d *, struct bpf_program *);
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	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_flags =	D_NEEDGIANT,
	.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 };

static int
bpf_movein(uio, linktype, mp, sockp, datlen)
	struct uio *uio;
	int linktype, *datlen;
	struct mbuf **mp;
	struct sockaddr *sockp;
{
	struct mbuf *m;
	int error;
	int len;
	int hlen;

	/*
	 * Build a sockaddr based on the data link layer type.
	 * We do this at this level because the ethernet header
	 * is copied directly into the data field of the sockaddr.
	 * In the case of SLIP, there is no header and the packet
	 * is forwarded as is.
	 * Also, we are careful to leave room at the front of the mbuf
	 * for the link level header.
	 */
	switch (linktype) {

	case DLT_SLIP:
		sockp->sa_family = AF_INET;
		hlen = 0;
		break;

	case DLT_EN10MB:
		sockp->sa_family = AF_UNSPEC;
		/* XXX Would MAXLINKHDR be better? */
		hlen = ETHER_HDR_LEN;
		break;

	case DLT_FDDI:
		sockp->sa_family = AF_IMPLINK;
		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;

	case DLT_PPP:
		sockp->sa_family = AF_UNSPEC;
		hlen = 4;	/* This should match PPP_HDRLEN */
		break;

	default:
		return (EIO);
	}

	len = uio->uio_resid;
	*datlen = len - hlen;
	if ((unsigned)len > MCLBYTES)
		return (EIO);

	if (len > MHLEN) {
		m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
	} else {
		MGETHDR(m, M_TRYWAIT, MT_DATA);
	}
	if (m == NULL)
		return (ENOBUFS);
	m->m_pkthdr.len = m->m_len = len;
	m->m_pkthdr.rcvif = NULL;
	*mp = m;

	/*
	 * Make room for link header.
	 */
	if (hlen != 0) {
		m->m_pkthdr.len -= hlen;
		m->m_len -= hlen;
#if BSD >= 199103
		m->m_data += hlen; /* XXX */
#else
		m->m_off += hlen;
#endif
		error = uiomove(sockp->sa_data, hlen, uio);
		if (error)
			goto bad;
	}
	error = uiomove(mtod(m, void *), len - hlen, uio);
	if (!error)
		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(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.
	 */
	BPFIF_LOCK(bp);
	d->bd_bif = bp;
	d->bd_next = bp->bif_dlist;
	bp->bif_dlist = d;

	*bp->bif_driverp = bp;
	BPFIF_UNLOCK(bp);
}

/*
 * Detach a file from its interface.
 */
static void
bpf_detachd(d)
	struct bpf_d *d;
{
	int error;
	struct bpf_d **p;
	struct bpf_if *bp;

	/* XXX locking */
	bp = d->bd_bif;
	d->bd_bif = 0;
	/*
	 * Check if this descriptor had requested promiscuous mode.
	 * If so, turn it off.
	 */
	if (d->bd_promisc) {
		d->bd_promisc = 0;
		error = ifpromisc(bp->bif_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);
		}
	}
	/* Remove d from the interface's descriptor list. */
	BPFIF_LOCK(bp);
	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.
		 */
		*bp->bif_driverp = 0;
	BPFIF_UNLOCK(bp);
}

/*
 * Open ethernet device.  Returns ENXIO for illegal minor device number,
 * EBUSY if file is open by another process.
 */
/* ARGSUSED */
static	int
bpfopen(dev, flags, fmt, td)
	dev_t 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) {
		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;
	d->bd_bufsize = bpf_bufsize;
	d->bd_sig = SIGIO;
	d->bd_seesent = 1;
#ifdef MAC
	mac_init_bpfdesc(d);
	mac_create_bpfdesc(td->td_ucred, d);
#endif
	mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF);
	callout_init(&d->bd_callout, CALLOUT_MPSAFE);

	return (0);
}

/*
 * Close the descriptor by detaching it from its interface,
 * deallocating its buffers, and marking it free.
 */
/* ARGSUSED */
static	int
bpfclose(dev, flags, fmt, td)
	dev_t 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);
#ifdef MAC
	mac_destroy_bpfdesc(d);
#endif /* MAC */
	bpf_freed(d);
	dev->si_drv1 = 0;
	free(d, M_BPF);

	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
bpfread(dev, uio, ioflag)
	dev_t 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);
	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 ((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 & IO_NDELAY) {
			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.
	 */
	error = uiomove(d->bd_hbuf, d->bd_hlen, uio);

	BPFD_LOCK(d);
	d->bd_fbuf = d->bd_hbuf;
	d->bd_hbuf = 0;
	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(d)
	struct bpf_d *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(&d->bd_sel.si_note, 0);
}

static void
bpf_timed_out(arg)
	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
bpfwrite(dev, uio, ioflag)
	dev_t dev;
	struct uio *uio;
	int ioflag;
{
	struct bpf_d *d = dev->si_drv1;
	struct ifnet *ifp;
	struct mbuf *m;
	int error;
	struct sockaddr dst;
	int datlen;

	if (d->bd_bif == 0)
		return (ENXIO);

	ifp = d->bd_bif->bif_ifp;

	if (uio->uio_resid == 0)
		return (0);

	bzero(&dst, sizeof(dst));
	error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen);
	if (error)
		return (error);

	if (datlen > ifp->if_mtu)
		return (EMSGSIZE);

	if (d->bd_hdrcmplt)
		dst.sa_family = pseudo_AF_HDRCMPLT;

#ifdef MAC
	BPFD_LOCK(d);
	mac_create_mbuf_from_bpfdesc(d, m);
	BPFD_UNLOCK(d);
#endif
	mtx_lock(&Giant);
	error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0);
	mtx_unlock(&Giant);
	/*
	 * The driver frees the mbuf.
	 */
	return (error);
}<commit_msg>Switch to conditionally acquiring and dropping Giant around calls into ifp->if_output() basedd on debug.mpsafenet.  That way once bpfwrite() can be called without Giant, it will acquire Giant (if desired) before entering the network stack.<commit_after>/*
 * 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 <NAME> and <NAME> 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
 *
 * $FreeBSD$
 */

#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/mac.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/filedesc.h>

#include <sys/event.h>
#include <sys/file.h>
#include <sys/poll.h>
#include <sys/proc.h>

#include <sys/socket.h>
#include <sys/vnode.h>

#include <net/if.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

static MALLOC_DEFINE(M_BPF, "BPF", "BPF data");

#if defined(DEV_BPF) || defined(NETGRAPH_BPF)

#define PRINET  26			/* interruptible */

/*
 * The default read buffer size is patchable.
 */
static int bpf_bufsize = 4096;
SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW,
	&bpf_bufsize, 0, "");
static int bpf_maxbufsize = BPF_MAXBUFSIZE;
SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW,
	&bpf_maxbufsize, 0, "");

/*
 *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
 */
static struct bpf_if	*bpf_iflist;
static struct mtx	bpf_mtx;		/* bpf global lock */

static int	bpf_allocbufs(struct bpf_d *);
static void	bpf_attachd(struct bpf_d *d, struct bpf_if *bp);
static void	bpf_detachd(struct bpf_d *d);
static void	bpf_freed(struct bpf_d *);
static void	bpf_mcopy(const void *, void *, size_t);
static int	bpf_movein(struct uio *, int,
		    struct mbuf **, struct sockaddr *, int *);
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 (*)(const void *, void *, size_t));
static void	reset_d(struct bpf_d *);
static int	 bpf_setf(struct bpf_d *, struct bpf_program *);
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	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_flags =	D_NEEDGIANT,
	.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 };

static int
bpf_movein(uio, linktype, mp, sockp, datlen)
	struct uio *uio;
	int linktype, *datlen;
	struct mbuf **mp;
	struct sockaddr *sockp;
{
	struct mbuf *m;
	int error;
	int len;
	int hlen;

	/*
	 * Build a sockaddr based on the data link layer type.
	 * We do this at this level because the ethernet header
	 * is copied directly into the data field of the sockaddr.
	 * In the case of SLIP, there is no header and the packet
	 * is forwarded as is.
	 * Also, we are careful to leave room at the front of the mbuf
	 * for the link level header.
	 */
	switch (linktype) {

	case DLT_SLIP:
		sockp->sa_family = AF_INET;
		hlen = 0;
		break;

	case DLT_EN10MB:
		sockp->sa_family = AF_UNSPEC;
		/* XXX Would MAXLINKHDR be better? */
		hlen = ETHER_HDR_LEN;
		break;

	case DLT_FDDI:
		sockp->sa_family = AF_IMPLINK;
		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;

	case DLT_PPP:
		sockp->sa_family = AF_UNSPEC;
		hlen = 4;	/* This should match PPP_HDRLEN */
		break;

	default:
		return (EIO);
	}

	len = uio->uio_resid;
	*datlen = len - hlen;
	if ((unsigned)len > MCLBYTES)
		return (EIO);

	if (len > MHLEN) {
		m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
	} else {
		MGETHDR(m, M_TRYWAIT, MT_DATA);
	}
	if (m == NULL)
		return (ENOBUFS);
	m->m_pkthdr.len = m->m_len = len;
	m->m_pkthdr.rcvif = NULL;
	*mp = m;

	/*
	 * Make room for link header.
	 */
	if (hlen != 0) {
		m->m_pkthdr.len -= hlen;
		m->m_len -= hlen;
#if BSD >= 199103
		m->m_data += hlen; /* XXX */
#else
		m->m_off += hlen;
#endif
		error = uiomove(sockp->sa_data, hlen, uio);
		if (error)
			goto bad;
	}
	error = uiomove(mtod(m, void *), len - hlen, uio);
	if (!error)
		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(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.
	 */
	BPFIF_LOCK(bp);
	d->bd_bif = bp;
	d->bd_next = bp->bif_dlist;
	bp->bif_dlist = d;

	*bp->bif_driverp = bp;
	BPFIF_UNLOCK(bp);
}

/*
 * Detach a file from its interface.
 */
static void
bpf_detachd(d)
	struct bpf_d *d;
{
	int error;
	struct bpf_d **p;
	struct bpf_if *bp;

	/* XXX locking */
	bp = d->bd_bif;
	d->bd_bif = 0;
	/*
	 * Check if this descriptor had requested promiscuous mode.
	 * If so, turn it off.
	 */
	if (d->bd_promisc) {
		d->bd_promisc = 0;
		error = ifpromisc(bp->bif_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);
		}
	}
	/* Remove d from the interface's descriptor list. */
	BPFIF_LOCK(bp);
	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.
		 */
		*bp->bif_driverp = 0;
	BPFIF_UNLOCK(bp);
}

/*
 * Open ethernet device.  Returns ENXIO for illegal minor device number,
 * EBUSY if file is open by another process.
 */
/* ARGSUSED */
static	int
bpfopen(dev, flags, fmt, td)
	dev_t 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) {
		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;
	d->bd_bufsize = bpf_bufsize;
	d->bd_sig = SIGIO;
	d->bd_seesent = 1;
#ifdef MAC
	mac_init_bpfdesc(d);
	mac_create_bpfdesc(td->td_ucred, d);
#endif
	mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF);
	callout_init(&d->bd_callout, CALLOUT_MPSAFE);

	return (0);
}

/*
 * Close the descriptor by detaching it from its interface,
 * deallocating its buffers, and marking it free.
 */
/* ARGSUSED */
static	int
bpfclose(dev, flags, fmt, td)
	dev_t 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);
#ifdef MAC
	mac_destroy_bpfdesc(d);
#endif /* MAC */
	bpf_freed(d);
	dev->si_drv1 = 0;
	free(d, M_BPF);

	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
bpfread(dev, uio, ioflag)
	dev_t 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);
	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 ((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 & IO_NDELAY) {
			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.
	 */
	error = uiomove(d->bd_hbuf, d->bd_hlen, uio);

	BPFD_LOCK(d);
	d->bd_fbuf = d->bd_hbuf;
	d->bd_hbuf = 0;
	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(d)
	struct bpf_d *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(&d->bd_sel.si_note, 0);
}

static void
bpf_timed_out(arg)
	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
bpfwrite(dev, uio, ioflag)
	dev_t dev;
	struct uio *uio;
	int ioflag;
{
	struct bpf_d *d = dev->si_drv1;
	struct ifnet *ifp;
	struct mbuf *m;
	int error;
	struct sockaddr dst;
	int datlen;

	if (d->bd_bif == 0)
		return (ENXIO);

	ifp = d->bd_bif->bif_ifp;

	if (uio->uio_resid == 0)
		return (0);

	bzero(&dst, sizeof(dst));
	error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen);
	if (error)
		return (error);

	if (datlen > ifp->if_mtu)
		return (EMSGSIZE);

	if (d->bd_hdrcmplt)
		dst.sa_family = pseudo_AF_HDRCMPLT;

#ifdef MAC
	BPFD_LOCK(d);
	mac_create_mbuf_from_bpfdesc(d, m);
	BPFD_UNLOCK(d);
#endif
	NET_LOCK_GIANT();
	error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0);
	NET_UNLOCK_GIANT();
	/*
	 * The driver frees the mbuf.
	 */
	return (error);
}
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{'dir': 'git-commits-cleaned', 'id': '1945112', 'n_tokens_mistral': 12083, 'n_tokens_neox': 11150, 'n_words': 3265}