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NetBSD/sys/net/bpf.c

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/* $NetBSD: bpf.c,v 1.189 2014/09/13 17:18:45 rmind Exp $ */
/*
* Copyright (c) 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from the Stanford/CMU enet packet filter,
* (net/enet.c) distributed as part of 4.3BSD, and code contributed
* to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
* Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)bpf.c 8.4 (Berkeley) 1/9/95
* static char rcsid[] =
* "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp ";
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.189 2014/09/13 17:18:45 rmind Exp $");
#if defined(_KERNEL_OPT)
#include "opt_bpf.h"
#include "sl.h"
#include "strip.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/buf.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/module.h>
#include <sys/once.h>
#include <sys/atomic.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/tty.h>
#include <sys/uio.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/poll.h>
#include <sys/sysctl.h>
#include <sys/kauth.h>
#include <net/if.h>
#include <net/slip.h>
#include <net/bpf.h>
#include <net/bpfdesc.h>
#include <net/bpfjit.h>
#include <net/if_arc.h>
#include <net/if_ether.h>
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#include <compat/sys/sockio.h>
#ifndef BPF_BUFSIZE
/*
* 4096 is too small for FDDI frames. 8192 is too small for gigabit Ethernet
* jumbos (circa 9k), ATM, or Intel gig/10gig ethernet jumbos (16k).
*/
# define BPF_BUFSIZE 32768
#endif
#define PRINET 26 /* interruptible */
/*
* The default read buffer size, and limit for BIOCSBLEN, is sysctl'able.
* XXX the default values should be computed dynamically based
* on available memory size and available mbuf clusters.
*/
int bpf_bufsize = BPF_BUFSIZE;
int bpf_maxbufsize = BPF_DFLTBUFSIZE; /* XXX set dynamically, see above */
bool bpf_jit = false;
struct bpfjit_ops bpfjit_module_ops = {
.bj_generate_code = NULL,
.bj_free_code = NULL
};
/*
* Global BPF statistics returned by net.bpf.stats sysctl.
*/
struct bpf_stat bpf_gstats;
/*
* Use a mutex to avoid a race condition between gathering the stats/peers
* and opening/closing the device.
*/
static kmutex_t bpf_mtx;
/*
* bpf_iflist is the list of interfaces; each corresponds to an ifnet
* bpf_dtab holds the descriptors, indexed by minor device #
*/
struct bpf_if *bpf_iflist;
LIST_HEAD(, bpf_d) bpf_list;
static int bpf_allocbufs(struct bpf_d *);
static void bpf_deliver(struct bpf_if *,
void *(*cpfn)(void *, const void *, size_t),
void *, u_int, u_int, const bool);
static void bpf_freed(struct bpf_d *);
static void bpf_ifname(struct ifnet *, struct ifreq *);
static void *bpf_mcpy(void *, const void *, size_t);
static int bpf_movein(struct uio *, int, uint64_t,
struct mbuf **, struct sockaddr *);
static void bpf_attachd(struct bpf_d *, struct bpf_if *);
static void bpf_detachd(struct bpf_d *);
static int bpf_setif(struct bpf_d *, struct ifreq *);
static void bpf_timed_out(void *);
static inline void
bpf_wakeup(struct bpf_d *);
static int bpf_hdrlen(struct bpf_d *);
static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
void *(*)(void *, const void *, size_t), struct timespec *);
static void reset_d(struct bpf_d *);
static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *);
static int bpf_setdlt(struct bpf_d *, u_int);
static int bpf_read(struct file *, off_t *, struct uio *, kauth_cred_t,
int);
static int bpf_write(struct file *, off_t *, struct uio *, kauth_cred_t,
int);
static int bpf_ioctl(struct file *, u_long, void *);
static int bpf_poll(struct file *, int);
static int bpf_stat(struct file *, struct stat *);
static int bpf_close(struct file *);
static int bpf_kqfilter(struct file *, struct knote *);
static void bpf_softintr(void *);
static const struct fileops bpf_fileops = {
.fo_read = bpf_read,
.fo_write = bpf_write,
.fo_ioctl = bpf_ioctl,
.fo_fcntl = fnullop_fcntl,
.fo_poll = bpf_poll,
.fo_stat = bpf_stat,
.fo_close = bpf_close,
.fo_kqfilter = bpf_kqfilter,
.fo_restart = fnullop_restart,
};
dev_type_open(bpfopen);
const struct cdevsw bpf_cdevsw = {
.d_open = bpfopen,
.d_close = noclose,
.d_read = noread,
.d_write = nowrite,
.d_ioctl = noioctl,
.d_stop = nostop,
.d_tty = notty,
.d_poll = nopoll,
.d_mmap = nommap,
.d_kqfilter = nokqfilter,
.d_discard = nodiscard,
.d_flag = D_OTHER
};
bpfjit_func_t
bpf_jit_generate(bpf_ctx_t *bc, void *code, size_t size)
{
membar_consumer();
if (bpfjit_module_ops.bj_generate_code != NULL) {
return bpfjit_module_ops.bj_generate_code(bc, code, size);
}
return NULL;
}
void
bpf_jit_freecode(bpfjit_func_t jcode)
{
KASSERT(bpfjit_module_ops.bj_free_code != NULL);
bpfjit_module_ops.bj_free_code(jcode);
}
static int
bpf_movein(struct uio *uio, int linktype, uint64_t mtu, struct mbuf **mp,
struct sockaddr *sockp)
{
struct mbuf *m;
int error;
size_t len;
size_t hlen;
size_t align;
/*
* Build a sockaddr based on the data link layer type.
* We do this at this level because the ethernet header
* is copied directly into the data field of the sockaddr.
* In the case of SLIP, there is no header and the packet
* is forwarded as is.
* Also, we are careful to leave room at the front of the mbuf
* for the link level header.
*/
switch (linktype) {
case DLT_SLIP:
sockp->sa_family = AF_INET;
hlen = 0;
align = 0;
break;
case DLT_PPP:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
align = 0;
break;
case DLT_EN10MB:
sockp->sa_family = AF_UNSPEC;
/* XXX Would MAXLINKHDR be better? */
/* 6(dst)+6(src)+2(type) */
hlen = sizeof(struct ether_header);
align = 2;
break;
case DLT_ARCNET:
sockp->sa_family = AF_UNSPEC;
hlen = ARC_HDRLEN;
align = 5;
break;
case DLT_FDDI:
sockp->sa_family = AF_LINK;
/* XXX 4(FORMAC)+6(dst)+6(src) */
hlen = 16;
align = 0;
break;
case DLT_ECONET:
sockp->sa_family = AF_UNSPEC;
hlen = 6;
align = 2;
break;
case DLT_NULL:
sockp->sa_family = AF_UNSPEC;
hlen = 0;
align = 0;
break;
default:
return (EIO);
}
len = uio->uio_resid;
/*
* If there aren't enough bytes for a link level header or the
* packet length exceeds the interface mtu, return an error.
*/
if (len - hlen > mtu)
return (EMSGSIZE);
/*
* XXX Avoid complicated buffer chaining ---
* bail if it won't fit in a single mbuf.
* (Take into account possible alignment bytes)
*/
if (len + align > MCLBYTES)
return (EIO);
m = m_gethdr(M_WAIT, MT_DATA);
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.len = (int)(len - hlen);
if (len + align > MHLEN) {
m_clget(m, M_WAIT);
if ((m->m_flags & M_EXT) == 0) {
error = ENOBUFS;
goto bad;
}
}
/* Insure the data is properly aligned */
if (align > 0) {
m->m_data += align;
m->m_len -= (int)align;
}
error = uiomove(mtod(m, void *), len, uio);
if (error)
goto bad;
if (hlen != 0) {
memcpy(sockp->sa_data, mtod(m, void *), hlen);
m->m_data += hlen; /* XXX */
len -= hlen;
}
m->m_len = (int)len;
*mp = m;
return (0);
bad:
m_freem(m);
return (error);
}
/*
* Attach file to the bpf interface, i.e. make d listen on bp.
* Must be called at splnet.
*/
static void
bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
{
/*
* Point d at bp, and add d to the interface's list of listeners.
* Finally, point the driver's bpf cookie at the interface so
* it will divert packets to bpf.
*/
d->bd_bif = bp;
d->bd_next = bp->bif_dlist;
bp->bif_dlist = d;
*bp->bif_driverp = bp;
}
/*
* Detach a file from its interface.
*/
static void
bpf_detachd(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 __diagused;
d->bd_promisc = 0;
/*
* Take device out of promiscuous mode. Since we were
* able to enter promiscuous mode, we should be able
* to turn it off. But we can get an error if
* the interface was configured down, so only panic
* if we don't get an unexpected error.
*/
error = ifpromisc(bp->bif_ifp, 0);
#ifdef DIAGNOSTIC
if (error)
printf("%s: ifpromisc failed: %d", __func__, error);
#endif
}
/* Remove d from the interface's descriptor list. */
p = &bp->bif_dlist;
while (*p != d) {
p = &(*p)->bd_next;
if (*p == NULL)
panic("%s: descriptor not in list", __func__);
}
*p = (*p)->bd_next;
if (bp->bif_dlist == NULL)
/*
* Let the driver know that there are no more listeners.
*/
*d->bd_bif->bif_driverp = NULL;
d->bd_bif = NULL;
}
static int
doinit(void)
{
mutex_init(&bpf_mtx, MUTEX_DEFAULT, IPL_NONE);
LIST_INIT(&bpf_list);
bpf_gstats.bs_recv = 0;
bpf_gstats.bs_drop = 0;
bpf_gstats.bs_capt = 0;
return 0;
}
/*
* bpfilterattach() is called at boot time.
*/
/* ARGSUSED */
void
bpfilterattach(int n)
{
static ONCE_DECL(control);
RUN_ONCE(&control, doinit);
}
/*
* Open ethernet device. Clones.
*/
/* ARGSUSED */
int
bpfopen(dev_t dev, int flag, int mode, struct lwp *l)
{
struct bpf_d *d;
struct file *fp;
int error, fd;
/* falloc() will use the descriptor for us. */
if ((error = fd_allocfile(&fp, &fd)) != 0)
return error;
d = malloc(sizeof(*d), M_DEVBUF, M_WAITOK|M_ZERO);
d->bd_bufsize = bpf_bufsize;
d->bd_seesent = 1;
d->bd_feedback = 0;
d->bd_pid = l->l_proc->p_pid;
#ifdef _LP64
if (curproc->p_flag & PK_32)
d->bd_compat32 = 1;
#endif
getnanotime(&d->bd_btime);
d->bd_atime = d->bd_mtime = d->bd_btime;
callout_init(&d->bd_callout, 0);
selinit(&d->bd_sel);
d->bd_sih = softint_establish(SOFTINT_CLOCK, bpf_softintr, d);
d->bd_jitcode = NULL;
mutex_enter(&bpf_mtx);
LIST_INSERT_HEAD(&bpf_list, d, bd_list);
mutex_exit(&bpf_mtx);
return fd_clone(fp, fd, flag, &bpf_fileops, d);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
/* ARGSUSED */
static int
bpf_close(struct file *fp)
{
struct bpf_d *d = fp->f_bpf;
int s;
KERNEL_LOCK(1, NULL);
/*
* Refresh the PID associated with this bpf file.
*/
d->bd_pid = curproc->p_pid;
s = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
if (d->bd_bif)
bpf_detachd(d);
splx(s);
bpf_freed(d);
mutex_enter(&bpf_mtx);
LIST_REMOVE(d, bd_list);
mutex_exit(&bpf_mtx);
callout_destroy(&d->bd_callout);
seldestroy(&d->bd_sel);
softint_disestablish(d->bd_sih);
free(d, M_DEVBUF);
fp->f_bpf = NULL;
KERNEL_UNLOCK_ONE(NULL);
return (0);
}
/*
* Rotate the packet buffers in descriptor d. Move the store buffer
* into the hold slot, and the free buffer into the store slot.
* Zero the length of the new store buffer.
*/
#define ROTATE_BUFFERS(d) \
(d)->bd_hbuf = (d)->bd_sbuf; \
(d)->bd_hlen = (d)->bd_slen; \
(d)->bd_sbuf = (d)->bd_fbuf; \
(d)->bd_slen = 0; \
(d)->bd_fbuf = NULL;
/*
* bpfread - read next chunk of packets from buffers
*/
static int
bpf_read(struct file *fp, off_t *offp, struct uio *uio,
kauth_cred_t cred, int flags)
{
struct bpf_d *d = fp->f_bpf;
int timed_out;
int error;
int s;
getnanotime(&d->bd_atime);
/*
* Restrict application to use a buffer the same size as
* the kernel buffers.
*/
if (uio->uio_resid != d->bd_bufsize)
return (EINVAL);
KERNEL_LOCK(1, NULL);
s = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
timed_out = (d->bd_state == BPF_TIMED_OUT);
d->bd_state = BPF_IDLE;
/*
* If the hold buffer is empty, then do a timed sleep, which
* ends when the timeout expires or when enough packets
* have arrived to fill the store buffer.
*/
while (d->bd_hbuf == NULL) {
if (fp->f_flag & FNONBLOCK) {
if (d->bd_slen == 0) {
splx(s);
KERNEL_UNLOCK_ONE(NULL);
return (EWOULDBLOCK);
}
ROTATE_BUFFERS(d);
break;
}
if ((d->bd_immediate || timed_out) && d->bd_slen != 0) {
/*
* A packet(s) either arrived since the previous
* read or arrived while we were asleep.
* Rotate the buffers and return what's here.
*/
ROTATE_BUFFERS(d);
break;
}
error = tsleep(d, PRINET|PCATCH, "bpf",
d->bd_rtout);
if (error == EINTR || error == ERESTART) {
splx(s);
KERNEL_UNLOCK_ONE(NULL);
return (error);
}
if (error == EWOULDBLOCK) {
/*
* On a timeout, return what's in the buffer,
* which may be nothing. If there is something
* in the store buffer, we can rotate the buffers.
*/
if (d->bd_hbuf)
/*
* We filled up the buffer in between
* getting the timeout and arriving
* here, so we don't need to rotate.
*/
break;
if (d->bd_slen == 0) {
splx(s);
KERNEL_UNLOCK_ONE(NULL);
return (0);
}
ROTATE_BUFFERS(d);
break;
}
if (error != 0)
goto done;
}
/*
* At this point, we know we have something in the hold slot.
*/
splx(s);
/*
* Move data from hold buffer into user space.
* We know the entire buffer is transferred since
* we checked above that the read buffer is bpf_bufsize bytes.
*/
error = uiomove(d->bd_hbuf, d->bd_hlen, uio);
s = splnet();
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
d->bd_hlen = 0;
done:
splx(s);
KERNEL_UNLOCK_ONE(NULL);
return (error);
}
/*
* If there are processes sleeping on this descriptor, wake them up.
*/
static inline void
bpf_wakeup(struct bpf_d *d)
{
wakeup(d);
if (d->bd_async)
softint_schedule(d->bd_sih);
selnotify(&d->bd_sel, 0, 0);
}
static void
bpf_softintr(void *cookie)
{
struct bpf_d *d;
d = cookie;
if (d->bd_async)
fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL);
}
static void
bpf_timed_out(void *arg)
{
struct bpf_d *d = arg;
int s;
s = splnet();
if (d->bd_state == BPF_WAITING) {
d->bd_state = BPF_TIMED_OUT;
if (d->bd_slen != 0)
bpf_wakeup(d);
}
splx(s);
}
static int
bpf_write(struct file *fp, off_t *offp, struct uio *uio,
kauth_cred_t cred, int flags)
{
struct bpf_d *d = fp->f_bpf;
struct ifnet *ifp;
struct mbuf *m, *mc;
int error, s;
static struct sockaddr_storage dst;
m = NULL; /* XXX gcc */
KERNEL_LOCK(1, NULL);
if (d->bd_bif == NULL) {
KERNEL_UNLOCK_ONE(NULL);
return (ENXIO);
}
getnanotime(&d->bd_mtime);
ifp = d->bd_bif->bif_ifp;
if (uio->uio_resid == 0) {
KERNEL_UNLOCK_ONE(NULL);
return (0);
}
error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, &m,
(struct sockaddr *) &dst);
if (error) {
KERNEL_UNLOCK_ONE(NULL);
return (error);
}
if (m->m_pkthdr.len > ifp->if_mtu) {
KERNEL_UNLOCK_ONE(NULL);
m_freem(m);
return (EMSGSIZE);
}
if (d->bd_hdrcmplt)
dst.ss_family = pseudo_AF_HDRCMPLT;
if (d->bd_feedback) {
mc = m_dup(m, 0, M_COPYALL, M_NOWAIT);
if (mc != NULL)
mc->m_pkthdr.rcvif = ifp;
/* Set M_PROMISC for outgoing packets to be discarded. */
if (1 /*d->bd_direction == BPF_D_INOUT*/)
m->m_flags |= M_PROMISC;
} else
mc = NULL;
s = splsoftnet();
error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL);
if (mc != NULL) {
if (error == 0)
(*ifp->if_input)(ifp, mc);
m_freem(mc);
}
splx(s);
KERNEL_UNLOCK_ONE(NULL);
/*
* The driver frees the mbuf.
*/
return (error);
}
/*
* Reset a descriptor by flushing its packet buffer and clearing the
* receive and drop counts. Should be called at splnet.
*/
static void
reset_d(struct bpf_d *d)
{
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_ccount = 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.
* 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.
* BIOCSFEEDBACK Set packet feedback mode.
* BIOCGFEEDBACK Get packet feedback mode.
* BIOCGSEESENT Get "see sent packets" mode.
* BIOCSSEESENT Set "see sent packets" mode.
*/
/* ARGSUSED */
static int
bpf_ioctl(struct file *fp, u_long cmd, void *addr)
{
struct bpf_d *d = fp->f_bpf;
int s, error = 0;
/*
* Refresh the PID associated with this bpf file.
*/
KERNEL_LOCK(1, NULL);
d->bd_pid = curproc->p_pid;
#ifdef _LP64
if (curproc->p_flag & PK_32)
d->bd_compat32 = 1;
else
d->bd_compat32 = 0;
#endif
s = splnet();
if (d->bd_state == BPF_WAITING)
callout_stop(&d->bd_callout);
d->bd_state = BPF_IDLE;
splx(s);
switch (cmd) {
default:
error = EINVAL;
break;
/*
* Check for read packet available.
*/
case FIONREAD:
{
int n;
s = splnet();
n = d->bd_slen;
if (d->bd_hbuf)
n += d->bd_hlen;
splx(s);
*(int *)addr = n;
break;
}
/*
* Get buffer len [for read()].
*/
case BIOCGBLEN:
*(u_int *)addr = d->bd_bufsize;
break;
/*
* Set buffer length.
*/
case BIOCSBLEN:
if (d->bd_bif != NULL)
error = EINVAL;
else {
u_int size = *(u_int *)addr;
if (size > bpf_maxbufsize)
*(u_int *)addr = size = bpf_maxbufsize;
else if (size < BPF_MINBUFSIZE)
*(u_int *)addr = size = BPF_MINBUFSIZE;
d->bd_bufsize = size;
}
break;
/*
* Set link layer read filter.
*/
case BIOCSETF:
error = bpf_setf(d, addr);
break;
/*
* Flush read packet buffer.
*/
case BIOCFLUSH:
s = splnet();
reset_d(d);
splx(s);
break;
/*
* Put interface into promiscuous mode.
*/
case BIOCPROMISC:
if (d->bd_bif == NULL) {
/*
* No interface attached yet.
*/
error = EINVAL;
break;
}
s = splnet();
if (d->bd_promisc == 0) {
error = ifpromisc(d->bd_bif->bif_ifp, 1);
if (error == 0)
d->bd_promisc = 1;
}
splx(s);
break;
/*
* Get device parameters.
*/
case BIOCGDLT:
if (d->bd_bif == NULL)
error = EINVAL;
else
*(u_int *)addr = d->bd_bif->bif_dlt;
break;
/*
* Get a list of supported device parameters.
*/
case BIOCGDLTLIST:
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_getdltlist(d, addr);
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.
*/
#ifdef OBIOCGETIF
case OBIOCGETIF:
#endif
case BIOCGETIF:
if (d->bd_bif == NULL)
error = EINVAL;
else
bpf_ifname(d->bd_bif->bif_ifp, addr);
break;
/*
* Set interface.
*/
#ifdef OBIOCSETIF
case OBIOCSETIF:
#endif
case BIOCSETIF:
error = bpf_setif(d, addr);
break;
/*
* Set read timeout.
*/
case BIOCSRTIMEOUT:
{
struct timeval *tv = addr;
/* Compute number of ticks. */
d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick;
if ((d->bd_rtout == 0) && (tv->tv_usec != 0))
d->bd_rtout = 1;
break;
}
#ifdef BIOCGORTIMEOUT
/*
* Get read timeout.
*/
case BIOCGORTIMEOUT:
{
struct timeval50 *tv = addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
break;
}
#endif
#ifdef BIOCSORTIMEOUT
/*
* Set read timeout.
*/
case BIOCSORTIMEOUT:
{
struct timeval50 *tv = addr;
/* Compute number of ticks. */
d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick;
if ((d->bd_rtout == 0) && (tv->tv_usec != 0))
d->bd_rtout = 1;
break;
}
#endif
/*
* Get read timeout.
*/
case BIOCGRTIMEOUT:
{
struct timeval *tv = addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
break;
}
/*
* Get packet stats.
*/
case BIOCGSTATS:
{
struct bpf_stat *bs = addr;
bs->bs_recv = d->bd_rcount;
bs->bs_drop = d->bd_dcount;
bs->bs_capt = d->bd_ccount;
break;
}
case BIOCGSTATSOLD:
{
struct bpf_stat_old *bs = addr;
bs->bs_recv = d->bd_rcount;
bs->bs_drop = d->bd_dcount;
break;
}
/*
* Set immediate mode.
*/
case BIOCIMMEDIATE:
d->bd_immediate = *(u_int *)addr;
break;
case BIOCVERSION:
{
struct bpf_version *bv = addr;
bv->bv_major = BPF_MAJOR_VERSION;
bv->bv_minor = BPF_MINOR_VERSION;
break;
}
case BIOCGHDRCMPLT: /* get "header already complete" flag */
*(u_int *)addr = d->bd_hdrcmplt;
break;
case BIOCSHDRCMPLT: /* set "header already complete" flag */
d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
break;
/*
* Get "see sent packets" flag
*/
case BIOCGSEESENT:
*(u_int *)addr = d->bd_seesent;
break;
/*
* Set "see sent" packets flag
*/
case BIOCSSEESENT:
d->bd_seesent = *(u_int *)addr;
break;
/*
* Set "feed packets from bpf back to input" mode
*/
case BIOCSFEEDBACK:
d->bd_feedback = *(u_int *)addr;
break;
/*
* Get "feed packets from bpf back to input" mode
*/
case BIOCGFEEDBACK:
*(u_int *)addr = d->bd_feedback;
break;
case FIONBIO: /* Non-blocking I/O */
/*
* No need to do anything special as we use IO_NDELAY in
* bpfread() as an indication of whether or not to block
* the read.
*/
break;
case FIOASYNC: /* Send signal on receive packets */
d->bd_async = *(int *)addr;
break;
case TIOCSPGRP: /* Process or group to send signals to */
case FIOSETOWN:
error = fsetown(&d->bd_pgid, cmd, addr);
break;
case TIOCGPGRP:
case FIOGETOWN:
error = fgetown(d->bd_pgid, cmd, addr);
break;
}
KERNEL_UNLOCK_ONE(NULL);
return (error);
}
/*
* Set d's packet filter program to fp. If this file already has a filter,
* free it and replace it. Returns EINVAL for bogus requests.
*/
int
bpf_setf(struct bpf_d *d, struct bpf_program *fp)
{
struct bpf_insn *fcode, *old;
bpfjit_func_t jcode, oldj;
size_t flen, size;
int s;
jcode = NULL;
flen = fp->bf_len;
if ((fp->bf_insns == NULL && flen) || flen > BPF_MAXINSNS) {
return EINVAL;
}
if (flen) {
/*
* Allocate the buffer, copy the byte-code from
* userspace and validate it.
*/
size = flen * sizeof(*fp->bf_insns);
fcode = malloc(size, M_DEVBUF, M_WAITOK);
if (copyin(fp->bf_insns, fcode, size) != 0 ||
!bpf_validate(fcode, (int)flen)) {
free(fcode, M_DEVBUF);
return EINVAL;
}
membar_consumer();
if (bpf_jit)
jcode = bpf_jit_generate(NULL, fcode, flen);
} else {
fcode = NULL;
}
s = splnet();
old = d->bd_filter;
d->bd_filter = fcode;
oldj = d->bd_jitcode;
d->bd_jitcode = jcode;
reset_d(d);
splx(s);
if (old) {
free(old, M_DEVBUF);
}
if (oldj) {
bpf_jit_freecode(oldj);
}
return 0;
}
/*
* Detach a file from its current interface (if attached at all) and attach
* to the interface indicated by the name stored in ifr.
* Return an errno or 0.
*/
static int
bpf_setif(struct bpf_d *d, struct ifreq *ifr)
{
struct bpf_if *bp;
char *cp;
int unit_seen, i, s, error;
/*
* Make sure the provided name has a unit number, and default
* it to '0' if not specified.
* XXX This is ugly ... do this differently?
*/
unit_seen = 0;
cp = ifr->ifr_name;
cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */
while (*cp++)
if (*cp >= '0' && *cp <= '9')
unit_seen = 1;
if (!unit_seen) {
/* Make sure to leave room for the '\0'. */
for (i = 0; i < (IFNAMSIZ - 1); ++i) {
if ((ifr->ifr_name[i] >= 'a' &&
ifr->ifr_name[i] <= 'z') ||
(ifr->ifr_name[i] >= 'A' &&
ifr->ifr_name[i] <= 'Z'))
continue;
ifr->ifr_name[i] = '0';
}
}
/*
* Look through attached interfaces for the named one.
*/
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
struct ifnet *ifp = bp->bif_ifp;
if (ifp == NULL ||
strcmp(ifp->if_xname, ifr->ifr_name) != 0)
continue;
/* skip additional entry */
if (bp->bif_driverp != &ifp->if_bpf)
continue;
/*
* We found the requested interface.
* Allocate the packet buffers if we need to.
* If we're already attached to requested interface,
* just flush the buffer.
*/
if (d->bd_sbuf == NULL) {
error = bpf_allocbufs(d);
if (error != 0)
return (error);
}
s = splnet();
if (bp != d->bd_bif) {
if (d->bd_bif)
/*
* Detach if attached to something else.
*/
bpf_detachd(d);
bpf_attachd(d, bp);
}
reset_d(d);
splx(s);
return (0);
}
/* Not found. */
return (ENXIO);
}
/*
* Copy the interface name to the ifreq.
*/
static void
bpf_ifname(struct ifnet *ifp, struct ifreq *ifr)
{
memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ);
}
static int
bpf_stat(struct file *fp, struct stat *st)
{
struct bpf_d *d = fp->f_bpf;
(void)memset(st, 0, sizeof(*st));
KERNEL_LOCK(1, NULL);
st->st_dev = makedev(cdevsw_lookup_major(&bpf_cdevsw), d->bd_pid);
st->st_atimespec = d->bd_atime;
st->st_mtimespec = d->bd_mtime;
st->st_ctimespec = st->st_birthtimespec = d->bd_btime;
st->st_uid = kauth_cred_geteuid(fp->f_cred);
st->st_gid = kauth_cred_getegid(fp->f_cred);
st->st_mode = S_IFCHR;
KERNEL_UNLOCK_ONE(NULL);
return 0;
}
/*
* Support for poll() system call
*
* Return true iff the specific operation will not block indefinitely - with
* the assumption that it is safe to positively acknowledge a request for the
* ability to write to the BPF device.
* Otherwise, return false but make a note that a selnotify() must be done.
*/
static int
bpf_poll(struct file *fp, int events)
{
struct bpf_d *d = fp->f_bpf;
int s = splnet();
int revents;
/*
* Refresh the PID associated with this bpf file.
*/
KERNEL_LOCK(1, NULL);
d->bd_pid = curproc->p_pid;
revents = events & (POLLOUT | POLLWRNORM);
if (events & (POLLIN | POLLRDNORM)) {
/*
* An imitation of the FIONREAD ioctl code.
*/
if (d->bd_hlen != 0 ||
((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) &&
d->bd_slen != 0)) {
revents |= events & (POLLIN | POLLRDNORM);
} else {
selrecord(curlwp, &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;
}
}
}
KERNEL_UNLOCK_ONE(NULL);
splx(s);
return (revents);
}
static void
filt_bpfrdetach(struct knote *kn)
{
struct bpf_d *d = kn->kn_hook;
int s;
KERNEL_LOCK(1, NULL);
s = splnet();
SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext);
splx(s);
KERNEL_UNLOCK_ONE(NULL);
}
static int
filt_bpfread(struct knote *kn, long hint)
{
struct bpf_d *d = kn->kn_hook;
int rv;
KERNEL_LOCK(1, NULL);
kn->kn_data = d->bd_hlen;
if (d->bd_immediate)
kn->kn_data += d->bd_slen;
rv = (kn->kn_data > 0);
KERNEL_UNLOCK_ONE(NULL);
return rv;
}
static const struct filterops bpfread_filtops =
{ 1, NULL, filt_bpfrdetach, filt_bpfread };
static int
bpf_kqfilter(struct file *fp, struct knote *kn)
{
struct bpf_d *d = fp->f_bpf;
struct klist *klist;
int s;
KERNEL_LOCK(1, NULL);
switch (kn->kn_filter) {
case EVFILT_READ:
klist = &d->bd_sel.sel_klist;
kn->kn_fop = &bpfread_filtops;
break;
default:
KERNEL_UNLOCK_ONE(NULL);
return (EINVAL);
}
kn->kn_hook = d;
s = splnet();
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
splx(s);
KERNEL_UNLOCK_ONE(NULL);
return (0);
}
/*
* Copy data from an mbuf chain into a buffer. This code is derived
* from m_copydata in sys/uipc_mbuf.c.
*/
static void *
bpf_mcpy(void *dst_arg, const void *src_arg, size_t len)
{
const struct mbuf *m;
u_int count;
u_char *dst;
m = src_arg;
dst = dst_arg;
while (len > 0) {
if (m == NULL)
panic("bpf_mcpy");
count = min(m->m_len, len);
memcpy(dst, mtod(m, const void *), count);
m = m->m_next;
dst += count;
len -= count;
}
return dst_arg;
}
/*
* Dispatch a packet to all the listeners on interface bp.
*
* pkt pointer to the packet, either a data buffer or an mbuf chain
* buflen buffer length, if pkt is a data buffer
* cpfn a function that can copy pkt into the listener's buffer
* pktlen length of the packet
* rcv true if packet came in
*/
static inline void
bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t),
void *pkt, u_int pktlen, u_int buflen, const bool rcv)
{
const bpf_ctx_t *bc = NULL;
uint32_t mem[BPF_MEMWORDS];
bpf_args_t args = {
.pkt = (const uint8_t *)pkt,
.wirelen = pktlen,
.buflen = buflen,
.mem = mem,
.arg = NULL
};
bool gottime = false;
struct timespec ts;
/*
* 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.
*/
for (struct bpf_d *d = bp->bif_dlist; d != NULL; d = d->bd_next) {
u_int slen;
if (!d->bd_seesent && !rcv) {
continue;
}
d->bd_rcount++;
bpf_gstats.bs_recv++;
if (d->bd_jitcode)
slen = d->bd_jitcode(bc, &args);
else
slen = bpf_filter_ext(bc, d->bd_filter, &args);
if (!slen) {
continue;
}
if (!gottime) {
gottime = true;
nanotime(&ts);
}
catchpacket(d, pkt, pktlen, slen, cpfn, &ts);
}
}
/*
* 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.
*/
static void
_bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
{
bpf_deliver(bp, memcpy, pkt, pktlen, pktlen, true);
}
/*
* Incoming linkage from device drivers, when the head of the packet is in
* a buffer, and the tail is in an mbuf chain.
*/
static void
_bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m)
{
u_int pktlen;
struct mbuf mb;
/* Skip outgoing duplicate packets. */
if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) {
m->m_flags &= ~M_PROMISC;
return;
}
pktlen = m_length(m) + dlen;
/*
* Craft on-stack mbuf suitable for passing to bpf_filter.
* Note that we cut corners here; we only setup what's
* absolutely needed--this mbuf should never go anywhere else.
*/
(void)memset(&mb, 0, sizeof(mb));
mb.m_next = m;
mb.m_data = data;
mb.m_len = dlen;
bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif != NULL);
}
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
*/
static void
_bpf_mtap(struct bpf_if *bp, struct mbuf *m)
{
void *(*cpfn)(void *, const void *, size_t);
u_int pktlen, buflen;
void *marg;
/* Skip outgoing duplicate packets. */
if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) {
m->m_flags &= ~M_PROMISC;
return;
}
pktlen = m_length(m);
if (pktlen == m->m_len) {
cpfn = (void *)memcpy;
marg = mtod(m, void *);
buflen = pktlen;
} else {
cpfn = bpf_mcpy;
marg = m;
buflen = 0;
}
bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif != NULL);
}
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
static void
_bpf_mtap_af(struct bpf_if *bp, uint32_t af, struct mbuf *m)
{
struct mbuf m0;
m0.m_flags = 0;
m0.m_next = m;
m0.m_len = 4;
m0.m_data = (char *)&af;
_bpf_mtap(bp, &m0);
}
/*
* Put the SLIP pseudo-"link header" in place.
* Note this M_PREPEND() should never fail,
* swince we know we always have enough space
* in the input buffer.
*/
static void
_bpf_mtap_sl_in(struct bpf_if *bp, u_char *chdr, struct mbuf **m)
{
int s;
u_char *hp;
M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT);
if (*m == NULL)
return;
hp = mtod(*m, u_char *);
hp[SLX_DIR] = SLIPDIR_IN;
(void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
s = splnet();
_bpf_mtap(bp, *m);
splx(s);
m_adj(*m, SLIP_HDRLEN);
}
/*
* Put the SLIP pseudo-"link header" in
* place. The compressed header is now
* at the beginning of the mbuf.
*/
static void
_bpf_mtap_sl_out(struct bpf_if *bp, u_char *chdr, struct mbuf *m)
{
struct mbuf m0;
u_char *hp;
int s;
m0.m_flags = 0;
m0.m_next = m;
m0.m_data = m0.m_dat;
m0.m_len = SLIP_HDRLEN;
hp = mtod(&m0, u_char *);
hp[SLX_DIR] = SLIPDIR_OUT;
(void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN);
s = splnet();
_bpf_mtap(bp, &m0);
splx(s);
m_freem(m);
}
static int
bpf_hdrlen(struct bpf_d *d)
{
int hdrlen = d->bd_bif->bif_hdrlen;
/*
* 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).
*/
#ifdef _LP64
if (d->bd_compat32)
return (BPF_WORDALIGN32(hdrlen + SIZEOF_BPF_HDR32) - hdrlen);
else
#endif
return (BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen);
}
/*
* Move the packet data from interface memory (pkt) into the
* store buffer. Call the wakeup functions if it's time to wakeup
* a listener (buffer full), "cpfn" is the routine called to do the
* actual data transfer. memcpy is passed in to copy contiguous chunks,
* while bpf_mcpy is passed in to copy mbuf chains. In the latter case,
* pkt is really an mbuf.
*/
static void
catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen,
void *(*cpfn)(void *, const void *, size_t), struct timespec *ts)
{
char *h;
int totlen, curlen, caplen;
int hdrlen = bpf_hdrlen(d);
int do_wakeup = 0;
++d->bd_ccount;
++bpf_gstats.bs_capt;
/*
* 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;
/*
* If we adjusted totlen to fit the bufsize, it could be that
* totlen is smaller than hdrlen because of the link layer header.
*/
caplen = totlen - hdrlen;
if (caplen < 0)
caplen = 0;
/*
* Round up the end of the previous packet to the next longword.
*/
#ifdef _LP64
if (d->bd_compat32)
curlen = BPF_WORDALIGN32(d->bd_slen);
else
#endif
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 == NULL) {
/*
* We haven't completed the previous read yet,
* so drop the packet.
*/
++d->bd_dcount;
++bpf_gstats.bs_drop;
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.
*/
h = (char *)d->bd_sbuf + curlen;
#ifdef _LP64
if (d->bd_compat32) {
struct bpf_hdr32 *hp32;
hp32 = (struct bpf_hdr32 *)h;
hp32->bh_tstamp.tv_sec = ts->tv_sec;
hp32->bh_tstamp.tv_usec = ts->tv_nsec / 1000;
hp32->bh_datalen = pktlen;
hp32->bh_hdrlen = hdrlen;
hp32->bh_caplen = caplen;
} else
#endif
{
struct bpf_hdr *hp;
hp = (struct bpf_hdr *)h;
hp->bh_tstamp.tv_sec = ts->tv_sec;
hp->bh_tstamp.tv_usec = ts->tv_nsec / 1000;
hp->bh_datalen = pktlen;
hp->bh_hdrlen = hdrlen;
hp->bh_caplen = caplen;
}
/*
* Copy the packet data into the store buffer and update its length.
*/
(*cpfn)(h + hdrlen, pkt, caplen);
d->bd_slen = curlen + totlen;
/*
* Call bpf_wakeup after bd_slen has been updated so that kevent(2)
* will cause filt_bpfread() to be called with it adjusted.
*/
if (do_wakeup)
bpf_wakeup(d);
}
/*
* Initialize all nonzero fields of a descriptor.
*/
static int
bpf_allocbufs(struct bpf_d *d)
{
d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL);
if (!d->bd_fbuf)
return (ENOBUFS);
d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL);
if (!d->bd_sbuf) {
free(d->bd_fbuf, M_DEVBUF);
return (ENOBUFS);
}
d->bd_slen = 0;
d->bd_hlen = 0;
return (0);
}
/*
* Free buffers currently in use by a descriptor.
* Called on close.
*/
static void
bpf_freed(struct bpf_d *d)
{
/*
* We don't need to lock out interrupts since this descriptor has
* been detached from its interface and it yet hasn't been marked
* free.
*/
if (d->bd_sbuf != NULL) {
free(d->bd_sbuf, M_DEVBUF);
if (d->bd_hbuf != NULL)
free(d->bd_hbuf, M_DEVBUF);
if (d->bd_fbuf != NULL)
free(d->bd_fbuf, M_DEVBUF);
}
if (d->bd_filter)
free(d->bd_filter, M_DEVBUF);
if (d->bd_jitcode != NULL) {
bpf_jit_freecode(d->bd_jitcode);
}
}
/*
* Attach an interface to bpf. dlt is the link layer type;
* hdrlen is the fixed size of the link header for the specified dlt
* (variable length headers not yet supported).
*/
static void
_bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp)
{
struct bpf_if *bp;
bp = malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT);
if (bp == NULL)
panic("bpfattach");
bp->bif_dlist = NULL;
bp->bif_driverp = driverp;
bp->bif_ifp = ifp;
bp->bif_dlt = dlt;
bp->bif_next = bpf_iflist;
bpf_iflist = bp;
*bp->bif_driverp = NULL;
bp->bif_hdrlen = hdrlen;
#if 0
printf("bpf: %s attached\n", ifp->if_xname);
#endif
}
/*
* Remove an interface from bpf.
*/
static void
_bpfdetach(struct ifnet *ifp)
{
struct bpf_if *bp, **pbp;
struct bpf_d *d;
int s;
/* Nuke the vnodes for any open instances */
LIST_FOREACH(d, &bpf_list, bd_list) {
if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) {
/*
* Detach the descriptor from an interface now.
* It will be free'ed later by close routine.
*/
s = splnet();
d->bd_promisc = 0; /* we can't touch device. */
bpf_detachd(d);
splx(s);
}
}
again:
for (bp = bpf_iflist, pbp = &bpf_iflist;
bp != NULL; pbp = &bp->bif_next, bp = bp->bif_next) {
if (bp->bif_ifp == ifp) {
*pbp = bp->bif_next;
free(bp, M_DEVBUF);
goto again;
}
}
}
/*
* Change the data link type of a interface.
*/
static void
_bpf_change_type(struct ifnet *ifp, u_int dlt, u_int hdrlen)
{
struct bpf_if *bp;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_driverp == &ifp->if_bpf)
break;
}
if (bp == NULL)
panic("bpf_change_type");
bp->bif_dlt = dlt;
bp->bif_hdrlen = hdrlen;
}
/*
* Get a list of available data link type of the interface.
*/
static int
bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
{
int n, error;
struct ifnet *ifp;
struct bpf_if *bp;
ifp = d->bd_bif->bif_ifp;
n = 0;
error = 0;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_ifp != ifp)
continue;
if (bfl->bfl_list != NULL) {
if (n >= bfl->bfl_len)
return ENOMEM;
error = copyout(&bp->bif_dlt,
bfl->bfl_list + n, sizeof(u_int));
}
n++;
}
bfl->bfl_len = n;
return error;
}
/*
* Set the data link type of a BPF instance.
*/
static int
bpf_setdlt(struct bpf_d *d, u_int dlt)
{
int s, error, opromisc;
struct ifnet *ifp;
struct bpf_if *bp;
if (d->bd_bif->bif_dlt == dlt)
return 0;
ifp = d->bd_bif->bif_ifp;
for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) {
if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
break;
}
if (bp == NULL)
return EINVAL;
s = splnet();
opromisc = d->bd_promisc;
bpf_detachd(d);
bpf_attachd(d, bp);
reset_d(d);
if (opromisc) {
error = ifpromisc(bp->bif_ifp, 1);
if (error)
printf("%s: bpf_setdlt: ifpromisc failed (%d)\n",
bp->bif_ifp->if_xname, error);
else
d->bd_promisc = 1;
}
splx(s);
return 0;
}
static int
sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS)
{
int newsize, error;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &newsize;
newsize = bpf_maxbufsize;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return (error);
if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE)
return (EINVAL);
bpf_maxbufsize = newsize;
return (0);
}
#if defined(MODULAR) || defined(BPFJIT)
static int
sysctl_net_bpf_jit(SYSCTLFN_ARGS)
{
bool newval;
int error;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &newval;
newval = bpf_jit;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error != 0 || newp == NULL)
return error;
bpf_jit = newval;
/*
* Do a full sync to publish new bpf_jit value and
* update bpfjit_module_ops.bj_generate_code variable.
*/
membar_sync();
if (newval && bpfjit_module_ops.bj_generate_code == NULL) {
printf("JIT compilation is postponed "
"until after bpfjit module is loaded\n");
}
return 0;
}
#endif
static int
sysctl_net_bpf_peers(SYSCTLFN_ARGS)
{
int error, elem_count;
struct bpf_d *dp;
struct bpf_d_ext dpe;
size_t len, needed, elem_size, out_size;
char *sp;
if (namelen == 1 && name[0] == CTL_QUERY)
return (sysctl_query(SYSCTLFN_CALL(rnode)));
if (namelen != 2)
return (EINVAL);
/* BPF peers is privileged information. */
error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_INTERFACE,
KAUTH_REQ_NETWORK_INTERFACE_GETPRIV, NULL, NULL, NULL);
if (error)
return (EPERM);
len = (oldp != NULL) ? *oldlenp : 0;
sp = oldp;
elem_size = name[0];
elem_count = name[1];
out_size = MIN(sizeof(dpe), elem_size);
needed = 0;
if (elem_size < 1 || elem_count < 0)
return (EINVAL);
mutex_enter(&bpf_mtx);
LIST_FOREACH(dp, &bpf_list, bd_list) {
if (len >= elem_size && elem_count > 0) {
#define BPF_EXT(field) dpe.bde_ ## field = dp->bd_ ## field
BPF_EXT(bufsize);
BPF_EXT(promisc);
BPF_EXT(state);
BPF_EXT(immediate);
BPF_EXT(hdrcmplt);
BPF_EXT(seesent);
BPF_EXT(pid);
BPF_EXT(rcount);
BPF_EXT(dcount);
BPF_EXT(ccount);
#undef BPF_EXT
if (dp->bd_bif)
(void)strlcpy(dpe.bde_ifname,
dp->bd_bif->bif_ifp->if_xname,
IFNAMSIZ - 1);
else
dpe.bde_ifname[0] = '\0';
error = copyout(&dpe, sp, out_size);
if (error)
break;
sp += elem_size;
len -= elem_size;
}
needed += elem_size;
if (elem_count > 0 && elem_count != INT_MAX)
elem_count--;
}
mutex_exit(&bpf_mtx);
*oldlenp = needed;
return (error);
}
static struct sysctllog *bpf_sysctllog;
static void
sysctl_net_bpf_setup(void)
{
const struct sysctlnode *node;
node = NULL;
sysctl_createv(&bpf_sysctllog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "bpf",
SYSCTL_DESCR("BPF options"),
NULL, 0, NULL, 0,
CTL_NET, CTL_CREATE, CTL_EOL);
if (node != NULL) {
#if defined(MODULAR) || defined(BPFJIT)
sysctl_createv(&bpf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_BOOL, "jit",
SYSCTL_DESCR("Toggle Just-In-Time compilation"),
sysctl_net_bpf_jit, 0, &bpf_jit, 0,
CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
#endif
sysctl_createv(&bpf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maxbufsize",
SYSCTL_DESCR("Maximum size for data capture buffer"),
sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0,
CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(&bpf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("BPF stats"),
NULL, 0, &bpf_gstats, sizeof(bpf_gstats),
CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
sysctl_createv(&bpf_sysctllog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "peers",
SYSCTL_DESCR("BPF peers"),
sysctl_net_bpf_peers, 0, NULL, 0,
CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
}
}
struct bpf_ops bpf_ops_kernel = {
.bpf_attach = _bpfattach,
.bpf_detach = _bpfdetach,
.bpf_change_type = _bpf_change_type,
.bpf_tap = _bpf_tap,
.bpf_mtap = _bpf_mtap,
.bpf_mtap2 = _bpf_mtap2,
.bpf_mtap_af = _bpf_mtap_af,
.bpf_mtap_sl_in = _bpf_mtap_sl_in,
.bpf_mtap_sl_out = _bpf_mtap_sl_out,
};
MODULE(MODULE_CLASS_DRIVER, bpf, NULL);
static int
bpf_modcmd(modcmd_t cmd, void *arg)
{
devmajor_t bmajor, cmajor;
int error;
bmajor = cmajor = NODEVMAJOR;
switch (cmd) {
case MODULE_CMD_INIT:
bpfilterattach(0);
error = devsw_attach("bpf", NULL, &bmajor,
&bpf_cdevsw, &cmajor);
if (error == EEXIST)
error = 0; /* maybe built-in ... improve eventually */
if (error)
break;
bpf_ops_handover_enter(&bpf_ops_kernel);
atomic_swap_ptr(&bpf_ops, &bpf_ops_kernel);
bpf_ops_handover_exit();
sysctl_net_bpf_setup();
break;
case MODULE_CMD_FINI:
/*
* While there is no reference counting for bpf callers,
* unload could at least in theory be done similarly to
* system call disestablishment. This should even be
* a little simpler:
*
* 1) replace op vector with stubs
* 2) post update to all cpus with xc
* 3) check that nobody is in bpf anymore
* (it's doubtful we'd want something like l_sysent,
* but we could do something like *signed* percpu
* counters. if the sum is 0, we're good).
* 4) if fail, unroll changes
*
* NOTE: change won't be atomic to the outside. some
* packets may be not captured even if unload is
* not succesful. I think packet capture not working
* is a perfectly logical consequence of trying to
* disable packet capture.
*/
error = EOPNOTSUPP;
/* insert sysctl teardown */
break;
default:
error = ENOTTY;
break;
}
return error;
}
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