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freebsd-skq/sys/net/bpf.c
jhb 520aafe3ec Add an external mbuf buffer type that holds multiple unmapped pages. 
Unmapped mbufs allow sendfile to carry multiple pages of data in a
single mbuf, without mapping those pages.  It is a requirement for
Netflix's in-kernel TLS, and provides a 5-10% CPU savings on heavy web
serving workloads when used by sendfile, due to effectively
compressing socket buffers by an order of magnitude, and hence
reducing cache misses.

For this new external mbuf buffer type (EXT_PGS), the ext_buf pointer
now points to a struct mbuf_ext_pgs structure instead of a data
buffer.  This structure contains an array of physical addresses (this
reduces cache misses compared to an earlier version that stored an
array of vm_page_t pointers).  It also stores additional fields needed
for in-kernel TLS such as the TLS header and trailer data that are
currently unused.  To more easily detect these mbufs, the M_NOMAP flag
is set in m_flags in addition to M_EXT.

Various functions like m_copydata() have been updated to safely access
packet contents (using uiomove_fromphys()), to make things like BPF
safe.

NIC drivers advertise support for unmapped mbufs on transmit via a new
IFCAP_NOMAP capability.  This capability can be toggled via the new
'nomap' and '-nomap' ifconfig(8) commands.  For NIC drivers that only
transmit packet contents via DMA and use bus_dma, adding the
capability to if_capabilities and if_capenable should be all that is
required.

If a NIC does not support unmapped mbufs, they are converted to a
chain of mapped mbufs (using sf_bufs to provide the mapping) in
ip_output or ip6_output.  If an unmapped mbuf requires software
checksums, it is also converted to a chain of mapped mbufs before
computing the checksum.

Submitted by:	gallatin (earlier version)
Reviewed by:	gallatin, hselasky, rrs
Discussed with:	ae, kp (firewalls)
Relnotes:	yes
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D20616
2019-06-29 00:48:33 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2019 Andrey V. Elsukov <ae@FreeBSD.org>
*
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bpf.h"
#include "opt_ddb.h"
#include "opt_netgraph.h"
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.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/sysent.h>
#include <sys/systm.h>
#include <sys/event.h>
#include <sys/file.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/socket.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.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 <net/route.h>
#include <net/vnet.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");
static struct bpf_if_ext dead_bpf_if = {
.bif_dlist = CK_LIST_HEAD_INITIALIZER()
};
struct bpf_if {
#define bif_next bif_ext.bif_next
#define bif_dlist bif_ext.bif_dlist
struct bpf_if_ext bif_ext; /* public members */
u_int bif_dlt; /* link layer type */
u_int bif_hdrlen; /* length of link header */
struct bpfd_list bif_wlist; /* writer-only list */
struct ifnet *bif_ifp; /* corresponding interface */
struct bpf_if **bif_bpf; /* Pointer to pointer to us */
volatile u_int bif_refcnt;
struct epoch_context epoch_ctx;
};
CTASSERT(offsetof(struct bpf_if, bif_ext) == 0);
struct bpf_program_buffer {
struct epoch_context epoch_ctx;
#ifdef BPF_JITTER
bpf_jit_filter *func;
#endif
void *buffer[0];
};
#if defined(DEV_BPF) || defined(NETGRAPH_BPF)
#define PRINET 26 /* interruptible */
#define SIZEOF_BPF_HDR(type) \
(offsetof(type, bh_hdrlen) + sizeof(((type *)0)->bh_hdrlen))
#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <compat/freebsd32/freebsd32.h>
#define BPF_ALIGNMENT32 sizeof(int32_t)
#define BPF_WORDALIGN32(x) roundup2(x, BPF_ALIGNMENT32)
#ifndef BURN_BRIDGES
/*
* 32-bit version of structure prepended to each packet. We use this header
* instead of the standard one for 32-bit streams. We mark the a stream as
* 32-bit the first time we see a 32-bit compat ioctl request.
*/
struct bpf_hdr32 {
struct timeval32 bh_tstamp; /* time stamp */
uint32_t bh_caplen; /* length of captured portion */
uint32_t bh_datalen; /* original length of packet */
uint16_t bh_hdrlen; /* length of bpf header (this struct
plus alignment padding) */
};
#endif
struct bpf_program32 {
u_int bf_len;
uint32_t bf_insns;
};
struct bpf_dltlist32 {
u_int bfl_len;
u_int bfl_list;
};
#define BIOCSETF32 _IOW('B', 103, struct bpf_program32)
#define BIOCSRTIMEOUT32 _IOW('B', 109, struct timeval32)
#define BIOCGRTIMEOUT32 _IOR('B', 110, struct timeval32)
#define BIOCGDLTLIST32 _IOWR('B', 121, struct bpf_dltlist32)
#define BIOCSETWF32 _IOW('B', 123, struct bpf_program32)
#define BIOCSETFNR32 _IOW('B', 130, struct bpf_program32)
#endif
#define BPF_LOCK() sx_xlock(&bpf_sx)
#define BPF_UNLOCK() sx_xunlock(&bpf_sx)
#define BPF_LOCK_ASSERT() sx_assert(&bpf_sx, SA_XLOCKED)
/*
* 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).
*/
CK_LIST_HEAD(bpf_iflist, bpf_if);
static struct bpf_iflist bpf_iflist;
static struct sx bpf_sx; /* bpf global lock */
static int bpf_bpfd_cnt;
static void bpfif_ref(struct bpf_if *);
static void bpfif_rele(struct bpf_if *);
static void bpfd_ref(struct bpf_d *);
static void bpfd_rele(struct bpf_d *);
static void bpf_attachd(struct bpf_d *, struct bpf_if *);
static void bpf_detachd(struct bpf_d *);
static void bpf_detachd_locked(struct bpf_d *, bool);
static void bpfd_free(epoch_context_t);
static int bpf_movein(struct uio *, int, struct ifnet *, struct mbuf **,
struct sockaddr *, int *, struct bpf_d *);
static int bpf_setif(struct bpf_d *, struct ifreq *);
static void bpf_timed_out(void *);
static __inline void
bpf_wakeup(struct bpf_d *);
static void catchpacket(struct bpf_d *, u_char *, u_int, u_int,
void (*)(struct bpf_d *, caddr_t, u_int, void *, u_int),
struct bintime *);
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 int bpf_stats_sysctl(SYSCTL_HANDLER_ARGS);
SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl");
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");
static SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_MPSAFE | CTLFLAG_RW,
bpf_stats_sysctl, "bpf statistics portal");
VNET_DEFINE_STATIC(int, bpf_optimize_writers) = 0;
#define V_bpf_optimize_writers VNET(bpf_optimize_writers)
SYSCTL_INT(_net_bpf, OID_AUTO, optimize_writers, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(bpf_optimize_writers), 0,
"Do not send packets until BPF program is set");
static d_open_t bpfopen;
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_read = bpfread,
.d_write = bpfwrite,
.d_ioctl = bpfioctl,
.d_poll = bpfpoll,
.d_name = "bpf",
.d_kqfilter = bpfkqfilter,
};
static struct filterops bpfread_filtops = {
.f_isfd = 1,
.f_detach = filt_bpfdetach,
.f_event = filt_bpfread,
};
/*
* LOCKING MODEL USED BY BPF
*
* Locks:
* 1) global lock (BPF_LOCK). Sx, used to protect some global counters,
* every bpf_iflist changes, serializes ioctl access to bpf descriptors.
* 2) Descriptor lock. Mutex, used to protect BPF buffers and various
* structure fields used by bpf_*tap* code.
*
* Lock order: global lock, then descriptor lock.
*
* There are several possible consumers:
*
* 1. The kernel registers interface pointer with bpfattach().
* Each call allocates new bpf_if structure, references ifnet pointer
* and links bpf_if into bpf_iflist chain. This is protected with global
* lock.
*
* 2. An userland application uses ioctl() call to bpf_d descriptor.
* All such call are serialized with global lock. BPF filters can be
* changed, but pointer to old filter will be freed using epoch_call().
* Thus it should be safe for bpf_tap/bpf_mtap* code to do access to
* filter pointers, even if change will happen during bpf_tap execution.
* Destroying of bpf_d descriptor also is doing using epoch_call().
*
* 3. An userland application can write packets into bpf_d descriptor.
* There we need to be sure, that ifnet won't disappear during bpfwrite().
*
* 4. The kernel invokes bpf_tap/bpf_mtap* functions. The access to
* bif_dlist is protected with net_epoch_preempt section. So, it should
* be safe to make access to bpf_d descriptor inside the section.
*
* 5. The kernel invokes bpfdetach() on interface destroying. All lists
* are modified with global lock held and actual free() is done using
* epoch_call().
*/
static void
bpfif_free(epoch_context_t ctx)
{
struct bpf_if *bp;
bp = __containerof(ctx, struct bpf_if, epoch_ctx);
if_rele(bp->bif_ifp);
free(bp, M_BPF);
}
static void
bpfif_ref(struct bpf_if *bp)
{
refcount_acquire(&bp->bif_refcnt);
}
static void
bpfif_rele(struct bpf_if *bp)
{
if (!refcount_release(&bp->bif_refcnt))
return;
epoch_call(net_epoch_preempt, &bp->epoch_ctx, bpfif_free);
}
static void
bpfd_ref(struct bpf_d *d)
{
refcount_acquire(&d->bd_refcnt);
}
static void
bpfd_rele(struct bpf_d *d)
{
if (!refcount_release(&d->bd_refcnt))
return;
epoch_call(net_epoch_preempt, &d->epoch_ctx, bpfd_free);
}
static struct bpf_program_buffer*
bpf_program_buffer_alloc(size_t size, int flags)
{
return (malloc(sizeof(struct bpf_program_buffer) + size,
M_BPF, flags));
}
static void
bpf_program_buffer_free(epoch_context_t ctx)
{
struct bpf_program_buffer *ptr;
ptr = __containerof(ctx, struct bpf_program_buffer, epoch_ctx);
#ifdef BPF_JITTER
if (ptr->func != NULL)
bpf_destroy_jit_filter(ptr->func);
#endif
free(ptr, M_BPF);
}
/*
* 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:
counter_u64_add(d->bd_zcopy, 1);
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:
counter_u64_add(d->bd_zcopy, 1);
return (bpf_zerocopy_append_mbuf(d, buf, offset, src, len));
default:
panic("bpf_buf_append_mbuf");
}
}
/*
* This function gets called when the free buffer is re-assigned.
*/
static void
bpf_buf_reclaimed(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
return;
case BPF_BUFMODE_ZBUF:
bpf_zerocopy_buf_reclaimed(d);
return;
default:
panic("bpf_buf_reclaimed");
}
}
/*
* 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_d *d)
{
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 || len - hlen > ifp->if_mtu)
return (EMSGSIZE);
m = m_get2(len, M_WAITOK, MT_DATA, M_PKTHDR);
if (m == NULL)
return (EIO);
m->m_pkthdr.len = m->m_len = len;
*mp = m;
error = uiomove(mtod(m, u_char *), len, uio);
if (error)
goto bad;
slen = bpf_filter(d->bd_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;
}
if (d->bd_hdrcmplt == 0) {
memcpy(eh->ether_shost, IF_LLADDR(ifp),
sizeof(eh->ether_shost));
}
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(mtod(m, const void *), sockp->sa_data, hlen);
}
*hdrlen = hlen;
return (0);
bad:
m_freem(m);
return (error);
}
/*
* Attach descriptor to the bpf interface, i.e. make d listen on bp,
* then reset its buffers and counters with reset_d().
*/
static void
bpf_attachd(struct bpf_d *d, struct bpf_if *bp)
{
int op_w;
BPF_LOCK_ASSERT();
/*
* Save sysctl value to protect from sysctl change
* between reads
*/
op_w = V_bpf_optimize_writers || d->bd_writer;
if (d->bd_bif != NULL)
bpf_detachd_locked(d, false);
/*
* Point d at bp, and add d to the interface's list.
* Since there are many applications using BPF for
* sending raw packets only (dhcpd, cdpd are good examples)
* we can delay adding d to the list of active listeners until
* some filter is configured.
*/
BPFD_LOCK(d);
/*
* Hold reference to bpif while descriptor uses this interface.
*/
bpfif_ref(bp);
d->bd_bif = bp;
if (op_w != 0) {
/* Add to writers-only list */
CK_LIST_INSERT_HEAD(&bp->bif_wlist, d, bd_next);
/*
* We decrement bd_writer on every filter set operation.
* First BIOCSETF is done by pcap_open_live() to set up
* snap length. After that appliation usually sets its own
* filter.
*/
d->bd_writer = 2;
} else
CK_LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next);
reset_d(d);
BPFD_UNLOCK(d);
bpf_bpfd_cnt++;
CTR3(KTR_NET, "%s: bpf_attach called by pid %d, adding to %s list",
__func__, d->bd_pid, d->bd_writer ? "writer" : "active");
if (op_w == 0)
EVENTHANDLER_INVOKE(bpf_track, bp->bif_ifp, bp->bif_dlt, 1);
}
/*
* Check if we need to upgrade our descriptor @d from write-only mode.
*/
static int
bpf_check_upgrade(u_long cmd, struct bpf_d *d, struct bpf_insn *fcode,
int flen)
{
int is_snap, need_upgrade;
/*
* Check if we've already upgraded or new filter is empty.
*/
if (d->bd_writer == 0 || fcode == NULL)
return (0);
need_upgrade = 0;
/*
* Check if cmd looks like snaplen setting from
* pcap_bpf.c:pcap_open_live().
* Note we're not checking .k value here:
* while pcap_open_live() definitely sets to non-zero value,
* we'd prefer to treat k=0 (deny ALL) case the same way: e.g.
* do not consider upgrading immediately
*/
if (cmd == BIOCSETF && flen == 1 &&
fcode[0].code == (BPF_RET | BPF_K))
is_snap = 1;
else
is_snap = 0;
if (is_snap == 0) {
/*
* We're setting first filter and it doesn't look like
* setting snaplen. We're probably using bpf directly.
* Upgrade immediately.
*/
need_upgrade = 1;
} else {
/*
* Do not require upgrade by first BIOCSETF
* (used to set snaplen) by pcap_open_live().
*/
if (--d->bd_writer == 0) {
/*
* First snaplen filter has already
* been set. This is probably catch-all
* filter
*/
need_upgrade = 1;
}
}
CTR5(KTR_NET,
"%s: filter function set by pid %d, "
"bd_writer counter %d, snap %d upgrade %d",
__func__, d->bd_pid, d->bd_writer,
is_snap, need_upgrade);
return (need_upgrade);
}
/*
* Detach a file from its interface.
*/
static void
bpf_detachd(struct bpf_d *d)
{
BPF_LOCK();
bpf_detachd_locked(d, false);
BPF_UNLOCK();
}
static void
bpf_detachd_locked(struct bpf_d *d, bool detached_ifp)
{
struct bpf_if *bp;
struct ifnet *ifp;
int error;
BPF_LOCK_ASSERT();
CTR2(KTR_NET, "%s: detach required by pid %d", __func__, d->bd_pid);
/* Check if descriptor is attached */
if ((bp = d->bd_bif) == NULL)
return;
BPFD_LOCK(d);
/* Remove d from the interface's descriptor list. */
CK_LIST_REMOVE(d, bd_next);
/* Save bd_writer value */
error = d->bd_writer;
ifp = bp->bif_ifp;
d->bd_bif = NULL;
if (detached_ifp) {
/*
* Notify descriptor as it's detached, so that any
* sleepers wake up and get ENXIO.
*/
bpf_wakeup(d);
}
BPFD_UNLOCK(d);
bpf_bpfd_cnt--;
/* Call event handler iff d is attached */
if (error == 0)
EVENTHANDLER_INVOKE(bpf_track, ifp, bp->bif_dlt, 0);
/*
* Check if this descriptor had requested promiscuous mode.
* If so and ifnet is not detached, turn it off.
*/
if (d->bd_promisc && !detached_ifp) {
d->bd_promisc = 0;
CURVNET_SET(ifp->if_vnet);
error = ifpromisc(ifp, 0);
CURVNET_RESTORE();
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);
}
}
bpfif_rele(bp);
}
/*
* Close the descriptor by detaching it from its interface,
* deallocating its buffers, and marking it free.
*/
static void
bpf_dtor(void *data)
{
struct bpf_d *d = data;
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);
bpf_detachd(d);
#ifdef MAC
mac_bpfdesc_destroy(d);
#endif /* MAC */
seldrain(&d->bd_sel);
knlist_destroy(&d->bd_sel.si_note);
callout_drain(&d->bd_callout);
bpfd_rele(d);
}
/*
* 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;
int error;
d = malloc(sizeof(*d), M_BPF, M_WAITOK | M_ZERO);
error = devfs_set_cdevpriv(d, bpf_dtor);
if (error != 0) {
free(d, M_BPF);
return (error);
}
/* Setup counters */
d->bd_rcount = counter_u64_alloc(M_WAITOK);
d->bd_dcount = counter_u64_alloc(M_WAITOK);
d->bd_fcount = counter_u64_alloc(M_WAITOK);
d->bd_wcount = counter_u64_alloc(M_WAITOK);
d->bd_wfcount = counter_u64_alloc(M_WAITOK);
d->bd_wdcount = counter_u64_alloc(M_WAITOK);
d->bd_zcopy = counter_u64_alloc(M_WAITOK);
/*
* 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);
if ((flags & FREAD) == 0)
d->bd_writer = 2;
d->bd_hbuf_in_use = 0;
d->bd_bufmode = BPF_BUFMODE_BUFFER;
d->bd_sig = SIGIO;
d->bd_direction = BPF_D_INOUT;
d->bd_refcnt = 1;
BPF_PID_REFRESH(d, td);
#ifdef MAC
mac_bpfdesc_init(d);
mac_bpfdesc_create(td->td_ucred, d);
#endif
mtx_init(&d->bd_lock, devtoname(dev), "bpf cdev lock", MTX_DEF);
callout_init_mtx(&d->bd_callout, &d->bd_lock, 0);
knlist_init_mtx(&d->bd_sel.si_note, &d->bd_lock);
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;
int error;
int non_block;
int timed_out;
error = devfs_get_cdevpriv((void **)&d);
if (error != 0)
return (error);
/*
* Restrict application to use a buffer the same size as
* as kernel buffers.
*/
if (uio->uio_resid != d->bd_bufsize)
return (EINVAL);
non_block = ((ioflag & O_NONBLOCK) != 0);
BPFD_LOCK(d);
BPF_PID_REFRESH_CUR(d);
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;
while (d->bd_hbuf_in_use) {
error = mtx_sleep(&d->bd_hbuf_in_use, &d->bd_lock,
PRINET|PCATCH, "bd_hbuf", 0);
if (error != 0) {
BPFD_UNLOCK(d);
return (error);
}
}
/*
* 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_slen != 0) {
/*
* A packet(s) either arrived since the previous
* read or arrived while we were asleep.
*/
if (d->bd_immediate || non_block || timed_out) {
/*
* Rotate the buffers and return what's here
* if we are in immediate mode, non-blocking
* flag is set, or this descriptor timed out.
*/
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 (non_block) {
BPFD_UNLOCK(d);
return (EWOULDBLOCK);
}
error = msleep(d, &d->bd_lock, 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.
*/
d->bd_hbuf_in_use = 1;
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.
*
* We do not have to worry about simultaneous reads because
* we waited for sole access to the hold buffer above.
*/
error = bpf_uiomove(d, d->bd_hbuf, d->bd_hlen, uio);
BPFD_LOCK(d);
KASSERT(d->bd_hbuf != NULL, ("bpfread: lost bd_hbuf"));
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
d->bd_hlen = 0;
bpf_buf_reclaimed(d);
d->bd_hbuf_in_use = 0;
wakeup(&d->bd_hbuf_in_use);
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_ASSERT(d);
if (callout_pending(&d->bd_callout) ||
!callout_active(&d->bd_callout))
return;
if (d->bd_state == BPF_WAITING) {
d->bd_state = BPF_TIMED_OUT;
if (d->bd_slen != 0)
bpf_wakeup(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 route ro;
struct sockaddr dst;
struct epoch_tracker et;
struct bpf_if *bp;
struct bpf_d *d;
struct ifnet *ifp;
struct mbuf *m, *mc;
int error, hlen;
error = devfs_get_cdevpriv((void **)&d);
if (error != 0)
return (error);
NET_EPOCH_ENTER(et);
BPFD_LOCK(d);
BPF_PID_REFRESH_CUR(d);
counter_u64_add(d->bd_wcount, 1);
if ((bp = d->bd_bif) == NULL) {
error = ENXIO;
goto out_locked;
}
ifp = bp->bif_ifp;
if ((ifp->if_flags & IFF_UP) == 0) {
error = ENETDOWN;
goto out_locked;
}
if (uio->uio_resid == 0)
goto out_locked;
bzero(&dst, sizeof(dst));
m = NULL;
hlen = 0;
/*
* Take extra reference, unlock d and exit from epoch section,
* since bpf_movein() can sleep.
*/
bpfd_ref(d);
NET_EPOCH_EXIT(et);
BPFD_UNLOCK(d);
error = bpf_movein(uio, (int)bp->bif_dlt, ifp,
&m, &dst, &hlen, d);
if (error != 0) {
counter_u64_add(d->bd_wdcount, 1);
bpfd_rele(d);
return (error);
}
BPFD_LOCK(d);
/*
* Check that descriptor is still attached to the interface.
* This can happen on bpfdetach(). To avoid access to detached
* ifnet, free mbuf and return ENXIO.
*/
if (d->bd_bif == NULL) {
counter_u64_add(d->bd_wdcount, 1);
BPFD_UNLOCK(d);
bpfd_rele(d);
m_freem(m);
return (ENXIO);
}
counter_u64_add(d->bd_wfcount, 1);
if (d->bd_hdrcmplt)
dst.sa_family = pseudo_AF_HDRCMPLT;
if (d->bd_feedback) {
mc = m_dup(m, M_NOWAIT);
if (mc != NULL)
mc->m_pkthdr.rcvif = ifp;
/* Set M_PROMISC for outgoing packets to be discarded. */
if (d->bd_direction == BPF_D_INOUT)
m->m_flags |= M_PROMISC;
} else
mc = NULL;
m->m_pkthdr.len -= hlen;
m->m_len -= hlen;
m->m_data += hlen; /* XXX */
CURVNET_SET(ifp->if_vnet);
#ifdef MAC
mac_bpfdesc_create_mbuf(d, m);
if (mc != NULL)
mac_bpfdesc_create_mbuf(d, mc);
#endif
bzero(&ro, sizeof(ro));
if (hlen != 0) {
ro.ro_prepend = (u_char *)&dst.sa_data;
ro.ro_plen = hlen;
ro.ro_flags = RT_HAS_HEADER;
}
/* Avoid possible recursion on BPFD_LOCK(). */
NET_EPOCH_ENTER(et);
BPFD_UNLOCK(d);
error = (*ifp->if_output)(ifp, m, &dst, &ro);
if (error)
counter_u64_add(d->bd_wdcount, 1);
if (mc != NULL) {
if (error == 0)
(*ifp->if_input)(ifp, mc);
else
m_freem(mc);
}
NET_EPOCH_EXIT(et);
CURVNET_RESTORE();
bpfd_rele(d);
return (error);
out_locked:
counter_u64_add(d->bd_wdcount, 1);
NET_EPOCH_EXIT(et);
BPFD_UNLOCK(d);
return (error);
}
/*
* Reset a descriptor by flushing its packet buffer and clearing the receive
* and drop counts. This is doable for kernel-only buffers, but with
* zero-copy buffers, we can't write to (or rotate) buffers that are
* currently owned by userspace. It would be nice if we could encapsulate
* this logic in the buffer code rather than here.
*/
static void
reset_d(struct bpf_d *d)
{
BPFD_LOCK_ASSERT(d);
while (d->bd_hbuf_in_use)
mtx_sleep(&d->bd_hbuf_in_use, &d->bd_lock, PRINET,
"bd_hbuf", 0);
if ((d->bd_hbuf != NULL) &&
(d->bd_bufmode != BPF_BUFMODE_ZBUF || bpf_canfreebuf(d))) {
/* Free the hold buffer. */
d->bd_fbuf = d->bd_hbuf;
d->bd_hbuf = NULL;
d->bd_hlen = 0;
bpf_buf_reclaimed(d);
}
if (bpf_canwritebuf(d))
d->bd_slen = 0;
counter_u64_zero(d->bd_rcount);
counter_u64_zero(d->bd_dcount);
counter_u64_zero(d->bd_fcount);
counter_u64_zero(d->bd_wcount);
counter_u64_zero(d->bd_wfcount);
counter_u64_zero(d->bd_wdcount);
counter_u64_zero(d->bd_zcopy);
}
/*
* FIONREAD Check for read packet available.
* BIOCGBLEN Get buffer len [for read()].
* BIOCSETF Set read filter.
* BIOCSETFNR Set read filter without resetting descriptor.
* BIOCSETWF Set 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
* BIOCGTSTAMP Get time stamp format and resolution.
* BIOCSTSTAMP Set time stamp format and resolution.
* 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;
int error;
error = devfs_get_cdevpriv((void **)&d);
if (error != 0)
return (error);
/*
* Refresh PID associated with this descriptor.
*/
BPFD_LOCK(d);
BPF_PID_REFRESH(d, td);
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:
#ifdef COMPAT_FREEBSD32
case BIOCGDLTLIST32:
#endif
case BIOCGETIF:
case BIOCGRTIMEOUT:
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
case BIOCGRTIMEOUT32:
#endif
case BIOCGSTATS:
case BIOCVERSION:
case BIOCGRSIG:
case BIOCGHDRCMPLT:
case BIOCSTSTAMP:
case BIOCFEEDBACK:
case FIONREAD:
case BIOCLOCK:
case BIOCSRTIMEOUT:
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
case BIOCSRTIMEOUT32:
#endif
case BIOCIMMEDIATE:
case TIOCGPGRP:
case BIOCROTZBUF:
break;
default:
return (EPERM);
}
}
#ifdef COMPAT_FREEBSD32
/*
* If we see a 32-bit compat ioctl, mark the stream as 32-bit so
* that it will get 32-bit packet headers.
*/
switch (cmd) {
case BIOCSETF32:
case BIOCSETFNR32:
case BIOCSETWF32:
case BIOCGDLTLIST32:
case BIOCGRTIMEOUT32:
case BIOCSRTIMEOUT32:
if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
BPFD_LOCK(d);
d->bd_compat32 = 1;
BPFD_UNLOCK(d);
}
}
#endif
CURVNET_SET(TD_TO_VNET(td));
switch (cmd) {
default:
error = EINVAL;
break;
/*
* Check for read packet available.
*/
case FIONREAD:
{
int n;
BPFD_LOCK(d);
n = d->bd_slen;
while (d->bd_hbuf_in_use)
mtx_sleep(&d->bd_hbuf_in_use, &d->bd_lock,
PRINET, "bd_hbuf", 0);
if (d->bd_hbuf)
n += d->bd_hlen;
BPFD_UNLOCK(d);
*(int *)addr = n;
break;
}
/*
* Get buffer len [for read()].
*/
case BIOCGBLEN:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_bufsize;
BPFD_UNLOCK(d);
break;
/*
* Set buffer length.
*/
case BIOCSBLEN:
error = bpf_ioctl_sblen(d, (u_int *)addr);
break;
/*
* Set link layer read filter.
*/
case BIOCSETF:
case BIOCSETFNR:
case BIOCSETWF:
#ifdef COMPAT_FREEBSD32
case BIOCSETF32:
case BIOCSETFNR32:
case BIOCSETWF32:
#endif
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:
BPF_LOCK();
if (d->bd_bif == NULL)
error = EINVAL;
else
*(u_int *)addr = d->bd_bif->bif_dlt;
BPF_UNLOCK();
break;
/*
* Get a list of supported data link types.
*/
#ifdef COMPAT_FREEBSD32
case BIOCGDLTLIST32:
{
struct bpf_dltlist32 *list32;
struct bpf_dltlist dltlist;
list32 = (struct bpf_dltlist32 *)addr;
dltlist.bfl_len = list32->bfl_len;
dltlist.bfl_list = PTRIN(list32->bfl_list);
BPF_LOCK();
if (d->bd_bif == NULL)
error = EINVAL;
else {
error = bpf_getdltlist(d, &dltlist);
if (error == 0)
list32->bfl_len = dltlist.bfl_len;
}
BPF_UNLOCK();
break;
}
#endif
case BIOCGDLTLIST:
BPF_LOCK();
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_getdltlist(d, (struct bpf_dltlist *)addr);
BPF_UNLOCK();
break;
/*
* Set data link type.
*/
case BIOCSDLT:
BPF_LOCK();
if (d->bd_bif == NULL)
error = EINVAL;
else
error = bpf_setdlt(d, *(u_int *)addr);
BPF_UNLOCK();
break;
/*
* Get interface name.
*/
case BIOCGETIF:
BPF_LOCK();
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));
}
BPF_UNLOCK();
break;
/*
* Set interface.
*/
case BIOCSETIF:
{
int alloc_buf, size;
/*
* 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.
*/
alloc_buf = 0;
BPFD_LOCK(d);
if (d->bd_bufmode == BPF_BUFMODE_BUFFER &&
d->bd_sbuf == NULL)
alloc_buf = 1;
BPFD_UNLOCK(d);
if (alloc_buf) {
size = d->bd_bufsize;
error = bpf_buffer_ioctl_sblen(d, &size);
if (error != 0)
break;
}
BPF_LOCK();
error = bpf_setif(d, (struct ifreq *)addr);
BPF_UNLOCK();
break;
}
/*
* Set read timeout.
*/
case BIOCSRTIMEOUT:
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
case BIOCSRTIMEOUT32:
#endif
{
struct timeval *tv = (struct timeval *)addr;
#if defined(COMPAT_FREEBSD32) && !defined(__mips__)
struct timeval32 *tv32;
struct timeval tv64;
if (cmd == BIOCSRTIMEOUT32) {
tv32 = (struct timeval32 *)addr;
tv = &tv64;
tv->tv_sec = tv32->tv_sec;
tv->tv_usec = tv32->tv_usec;
} else
#endif
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:
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
case BIOCGRTIMEOUT32:
#endif
{
struct timeval *tv;
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
struct timeval32 *tv32;
struct timeval tv64;
if (cmd == BIOCGRTIMEOUT32)
tv = &tv64;
else
#endif
tv = (struct timeval *)addr;
tv->tv_sec = d->bd_rtout / hz;
tv->tv_usec = (d->bd_rtout % hz) * tick;
#if defined(COMPAT_FREEBSD32) && defined(__amd64__)
if (cmd == BIOCGRTIMEOUT32) {
tv32 = (struct timeval32 *)addr;
tv32->tv_sec = tv->tv_sec;
tv32->tv_usec = tv->tv_usec;
}
#endif
break;
}
/*
* Get packet stats.
*/
case BIOCGSTATS:
{
struct bpf_stat *bs = (struct bpf_stat *)addr;
/* XXXCSJP overflow */
bs->bs_recv = (u_int)counter_u64_fetch(d->bd_rcount);
bs->bs_drop = (u_int)counter_u64_fetch(d->bd_dcount);
break;
}
/*
* Set immediate mode.
*/
case BIOCIMMEDIATE:
BPFD_LOCK(d);
d->bd_immediate = *(u_int *)addr;
BPFD_UNLOCK(d);
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:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_hdrcmplt;
BPFD_UNLOCK(d);
break;
/*
* Set "header already complete" flag
*/
case BIOCSHDRCMPLT:
BPFD_LOCK(d);
d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0;
BPFD_UNLOCK(d);
break;
/*
* Get packet direction flag
*/
case BIOCGDIRECTION:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_direction;
BPFD_UNLOCK(d);
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:
BPFD_LOCK(d);
d->bd_direction = direction;
BPFD_UNLOCK(d);
break;
default:
error = EINVAL;
}
}
break;
/*
* Get packet timestamp format and resolution.
*/
case BIOCGTSTAMP:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_tstamp;
BPFD_UNLOCK(d);
break;
/*
* Set packet timestamp format and resolution.
*/
case BIOCSTSTAMP:
{
u_int func;
func = *(u_int *)addr;
if (BPF_T_VALID(func))
d->bd_tstamp = func;
else
error = EINVAL;
}
break;
case BIOCFEEDBACK:
BPFD_LOCK(d);
d->bd_feedback = *(u_int *)addr;
BPFD_UNLOCK(d);
break;
case BIOCLOCK:
BPFD_LOCK(d);
d->bd_locked = 1;
BPFD_UNLOCK(d);
break;
case FIONBIO: /* Non-blocking I/O */
break;
case FIOASYNC: /* Send signal on receive packets */
BPFD_LOCK(d);
d->bd_async = *(int *)addr;
BPFD_UNLOCK(d);
break;
case FIOSETOWN:
/*
* XXX: Add some sort of locking here?
* fsetown() can sleep.
*/
error = fsetown(*(int *)addr, &d->bd_sigio);
break;
case FIOGETOWN:
BPFD_LOCK(d);
*(int *)addr = fgetown(&d->bd_sigio);
BPFD_UNLOCK(d);
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 {
BPFD_LOCK(d);
d->bd_sig = sig;
BPFD_UNLOCK(d);
}
break;
}
case BIOCGRSIG:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_sig;
BPFD_UNLOCK(d);
break;
case BIOCGETBUFMODE:
BPFD_LOCK(d);
*(u_int *)addr = d->bd_bufmode;
BPFD_UNLOCK(d);
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:
CURVNET_RESTORE();
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);
CURVNET_RESTORE();
return (EBUSY);
}
d->bd_bufmode = *(u_int *)addr;
BPFD_UNLOCK(d);
break;
case BIOCGETZMAX:
error = bpf_ioctl_getzmax(td, d, (size_t *)addr);
break;
case BIOCSETZBUF:
error = bpf_ioctl_setzbuf(td, d, (struct bpf_zbuf *)addr);
break;
case BIOCROTZBUF:
error = bpf_ioctl_rotzbuf(td, d, (struct bpf_zbuf *)addr);
break;
}
CURVNET_RESTORE();
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.
*
* Note we use global lock here to serialize bpf_setf() and bpf_setif()
* calls.
*/
static int
bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
{
#ifdef COMPAT_FREEBSD32
struct bpf_program fp_swab;
struct bpf_program32 *fp32;
#endif
struct bpf_program_buffer *fcode;
struct bpf_insn *filter;
#ifdef BPF_JITTER
bpf_jit_filter *jfunc;
#endif
size_t size;
u_int flen;
bool track_event;
#ifdef COMPAT_FREEBSD32
switch (cmd) {
case BIOCSETF32:
case BIOCSETWF32:
case BIOCSETFNR32:
fp32 = (struct bpf_program32 *)fp;
fp_swab.bf_len = fp32->bf_len;
fp_swab.bf_insns =
(struct bpf_insn *)(uintptr_t)fp32->bf_insns;
fp = &fp_swab;
switch (cmd) {
case BIOCSETF32:
cmd = BIOCSETF;
break;
case BIOCSETWF32:
cmd = BIOCSETWF;
break;
}
break;
}
#endif
filter = NULL;
#ifdef BPF_JITTER
jfunc = NULL;
#endif
/*
* Check new filter validness before acquiring any locks.
* Allocate memory for new filter, if needed.
*/
flen = fp->bf_len;
if (flen > bpf_maxinsns || (fp->bf_insns == NULL && flen != 0))
return (EINVAL);
size = flen * sizeof(*fp->bf_insns);
if (size > 0) {
/* We're setting up new filter. Copy and check actual data. */
fcode = bpf_program_buffer_alloc(size, M_WAITOK);
filter = (struct bpf_insn *)fcode->buffer;
if (copyin(fp->bf_insns, filter, size) != 0 ||
!bpf_validate(filter, flen)) {
free(fcode, M_BPF);
return (EINVAL);
}
#ifdef BPF_JITTER
if (cmd != BIOCSETWF) {
/*
* Filter is copied inside fcode and is
* perfectly valid.
*/
jfunc = bpf_jitter(filter, flen);
}
#endif
}
track_event = false;
fcode = NULL;
BPF_LOCK();
BPFD_LOCK(d);
/* Set up new filter. */
if (cmd == BIOCSETWF) {
if (d->bd_wfilter != NULL) {
fcode = __containerof((void *)d->bd_wfilter,
struct bpf_program_buffer, buffer);
#ifdef BPF_JITTER
fcode->func = NULL;
#endif
}
d->bd_wfilter = filter;
} else {
if (d->bd_rfilter != NULL) {
fcode = __containerof((void *)d->bd_rfilter,
struct bpf_program_buffer, buffer);
#ifdef BPF_JITTER
fcode->func = d->bd_bfilter;
#endif
}
d->bd_rfilter = filter;
#ifdef BPF_JITTER
d->bd_bfilter = jfunc;
#endif
if (cmd == BIOCSETF)
reset_d(d);
if (bpf_check_upgrade(cmd, d, filter, flen) != 0) {
/*
* Filter can be set several times without
* specifying interface. In this case just mark d
* as reader.
*/
d->bd_writer = 0;
if (d->bd_bif != NULL) {
/*
* Remove descriptor from writers-only list
* and add it to active readers list.
*/
CK_LIST_REMOVE(d, bd_next);
CK_LIST_INSERT_HEAD(&d->bd_bif->bif_dlist,
d, bd_next);
CTR2(KTR_NET,
"%s: upgrade required by pid %d",
__func__, d->bd_pid);
track_event = true;
}
}
}
BPFD_UNLOCK(d);
if (fcode != NULL)
epoch_call(net_epoch_preempt, &fcode->epoch_ctx,
bpf_program_buffer_free);
if (track_event)
EVENTHANDLER_INVOKE(bpf_track,
d->bd_bif->bif_ifp, d->bd_bif->bif_dlt, 1);
BPF_UNLOCK();
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;
struct ifnet *theywant;
BPF_LOCK_ASSERT();
theywant = ifunit(ifr->ifr_name);
if (theywant == NULL || theywant->if_bpf == NULL)
return (ENXIO);
bp = theywant->if_bpf;
/*
* At this point, we expect the buffer is already allocated. If not,
* return an error.
*/
switch (d->bd_bufmode) {
case BPF_BUFMODE_BUFFER:
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)
bpf_attachd(d, bp);
else {
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;
if (devfs_get_cdevpriv((void **)&d) != 0 || d->bd_bif == NULL)
return (events &
(POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
/*
* Refresh PID associated with this descriptor.
*/
revents = events & (POLLOUT | POLLWRNORM);
BPFD_LOCK(d);
BPF_PID_REFRESH(d, td);
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;
if (devfs_get_cdevpriv((void **)&d) != 0 ||
kn->kn_filter != EVFILT_READ)
return (1);
/*
* Refresh PID associated with this descriptor.
*/
BPFD_LOCK(d);
BPF_PID_REFRESH_CUR(d);
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;
/*
* Ignore the hold buffer if it is being copied to user space.
*/
if (!d->bd_hbuf_in_use && 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);
}
#define BPF_TSTAMP_NONE 0
#define BPF_TSTAMP_FAST 1
#define BPF_TSTAMP_NORMAL 2
#define BPF_TSTAMP_EXTERN 3
static int
bpf_ts_quality(int tstype)
{
if (tstype == BPF_T_NONE)
return (BPF_TSTAMP_NONE);
if ((tstype & BPF_T_FAST) != 0)
return (BPF_TSTAMP_FAST);
return (BPF_TSTAMP_NORMAL);
}
static int
bpf_gettime(struct bintime *bt, int tstype, struct mbuf *m)
{
struct m_tag *tag;
int quality;
quality = bpf_ts_quality(tstype);
if (quality == BPF_TSTAMP_NONE)
return (quality);
if (m != NULL) {
tag = m_tag_locate(m, MTAG_BPF, MTAG_BPF_TIMESTAMP, NULL);
if (tag != NULL) {
*bt = *(struct bintime *)(tag + 1);
return (BPF_TSTAMP_EXTERN);
}
}
if (quality == BPF_TSTAMP_NORMAL)
binuptime(bt);
else
getbinuptime(bt);
return (quality);
}
/*
* 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 epoch_tracker et;
struct bintime bt;
struct bpf_d *d;
#ifdef BPF_JITTER
bpf_jit_filter *bf;
#endif
u_int slen;
int gottime;
gottime = BPF_TSTAMP_NONE;
NET_EPOCH_ENTER(et);
CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
counter_u64_add(d->bd_rcount, 1);
/*
* NB: We dont call BPF_CHECK_DIRECTION() here since there
* is no way for the caller to indiciate to us whether this
* packet is inbound or outbound. In the bpf_mtap() routines,
* we use the interface pointers on the mbuf to figure it out.
*/
#ifdef BPF_JITTER
bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL;
if (bf != NULL)
slen = (*(bf->func))(pkt, pktlen, pktlen);
else
#endif
slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen);
if (slen != 0) {
/*
* Filter matches. Let's to acquire write lock.
*/
BPFD_LOCK(d);
counter_u64_add(d->bd_fcount, 1);
if (gottime < bpf_ts_quality(d->bd_tstamp))
gottime = bpf_gettime(&bt, d->bd_tstamp,
NULL);
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, pkt, pktlen, slen,
bpf_append_bytes, &bt);
BPFD_UNLOCK(d);
}
}
NET_EPOCH_EXIT(et);
}
#define BPF_CHECK_DIRECTION(d, r, i) \
(((d)->bd_direction == BPF_D_IN && (r) != (i)) || \
((d)->bd_direction == BPF_D_OUT && (r) == (i)))
/*
* Incoming linkage from device drivers, when packet is in an mbuf chain.
* Locking model is explained in bpf_tap().
*/
void
bpf_mtap(struct bpf_if *bp, struct mbuf *m)
{
struct epoch_tracker et;
struct bintime bt;
struct bpf_d *d;
#ifdef BPF_JITTER
bpf_jit_filter *bf;
#endif
u_int pktlen, slen;
int gottime;
/* Skip outgoing duplicate packets. */
if ((m->m_flags & M_PROMISC) != 0 && m_rcvif(m) == NULL) {
m->m_flags &= ~M_PROMISC;
return;
}
pktlen = m_length(m, NULL);
gottime = BPF_TSTAMP_NONE;
NET_EPOCH_ENTER(et);
CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
if (BPF_CHECK_DIRECTION(d, m_rcvif(m), bp->bif_ifp))
continue;
counter_u64_add(d->bd_rcount, 1);
#ifdef BPF_JITTER
bf = bpf_jitter_enable != 0 ? d->bd_bfilter : NULL;
/* XXX We cannot handle multiple mbufs. */
if (bf != NULL && m->m_next == NULL)
slen = (*(bf->func))(mtod(m, u_char *), pktlen,
pktlen);
else
#endif
slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0);
if (slen != 0) {
BPFD_LOCK(d);
counter_u64_add(d->bd_fcount, 1);
if (gottime < bpf_ts_quality(d->bd_tstamp))
gottime = bpf_gettime(&bt, d->bd_tstamp, m);
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, (u_char *)m, pktlen, slen,
bpf_append_mbuf, &bt);
BPFD_UNLOCK(d);
}
}
NET_EPOCH_EXIT(et);
}
/*
* 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 epoch_tracker et;
struct bintime bt;
struct mbuf mb;
struct bpf_d *d;
u_int pktlen, slen;
int gottime;
/* 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, 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_flags = 0;
mb.m_next = m;
mb.m_data = data;
mb.m_len = dlen;
pktlen += dlen;
gottime = BPF_TSTAMP_NONE;
NET_EPOCH_ENTER(et);
CK_LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
if (BPF_CHECK_DIRECTION(d, m->m_pkthdr.rcvif, bp->bif_ifp))
continue;
counter_u64_add(d->bd_rcount, 1);
slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0);
if (slen != 0) {
BPFD_LOCK(d);
counter_u64_add(d->bd_fcount, 1);
if (gottime < bpf_ts_quality(d->bd_tstamp))
gottime = bpf_gettime(&bt, d->bd_tstamp, m);
#ifdef MAC
if (mac_bpfdesc_check_receive(d, bp->bif_ifp) == 0)
#endif
catchpacket(d, (u_char *)&mb, pktlen, slen,
bpf_append_mbuf, &bt);
BPFD_UNLOCK(d);
}
}
NET_EPOCH_EXIT(et);
}
#undef BPF_CHECK_DIRECTION
#undef BPF_TSTAMP_NONE
#undef BPF_TSTAMP_FAST
#undef BPF_TSTAMP_NORMAL
#undef BPF_TSTAMP_EXTERN
static int
bpf_hdrlen(struct bpf_d *d)
{
int hdrlen;
hdrlen = d->bd_bif->bif_hdrlen;
#ifndef BURN_BRIDGES
if (d->bd_tstamp == BPF_T_NONE ||
BPF_T_FORMAT(d->bd_tstamp) == BPF_T_MICROTIME)
#ifdef COMPAT_FREEBSD32
if (d->bd_compat32)
hdrlen += SIZEOF_BPF_HDR(struct bpf_hdr32);
else
#endif
hdrlen += SIZEOF_BPF_HDR(struct bpf_hdr);
else
#endif
hdrlen += SIZEOF_BPF_HDR(struct bpf_xhdr);
#ifdef COMPAT_FREEBSD32
if (d->bd_compat32)
hdrlen = BPF_WORDALIGN32(hdrlen);
else
#endif
hdrlen = BPF_WORDALIGN(hdrlen);
return (hdrlen - d->bd_bif->bif_hdrlen);
}
static void
bpf_bintime2ts(struct bintime *bt, struct bpf_ts *ts, int tstype)
{
struct bintime bt2, boottimebin;
struct timeval tsm;
struct timespec tsn;
if ((tstype & BPF_T_MONOTONIC) == 0) {
bt2 = *bt;
getboottimebin(&boottimebin);
bintime_add(&bt2, &boottimebin);
bt = &bt2;
}
switch (BPF_T_FORMAT(tstype)) {
case BPF_T_MICROTIME:
bintime2timeval(bt, &tsm);
ts->bt_sec = tsm.tv_sec;
ts->bt_frac = tsm.tv_usec;
break;
case BPF_T_NANOTIME:
bintime2timespec(bt, &tsn);
ts->bt_sec = tsn.tv_sec;
ts->bt_frac = tsn.tv_nsec;
break;
case BPF_T_BINTIME:
ts->bt_sec = bt->sec;
ts->bt_frac = bt->frac;
break;
}
}
/*
* 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 bintime *bt)
{
struct bpf_xhdr hdr;
#ifndef BURN_BRIDGES
struct bpf_hdr hdr_old;
#ifdef COMPAT_FREEBSD32
struct bpf_hdr32 hdr32_old;
#endif
#endif
int caplen, curlen, hdrlen, totlen;
int do_wakeup = 0;
int do_timestamp;
int tstype;
BPFD_LOCK_ASSERT(d);
if (d->bd_bif == NULL) {
/* Descriptor was detached in concurrent thread */
counter_u64_add(d->bd_dcount, 1);
return;
}
/*
* 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;
bpf_buf_reclaimed(d);
}
/*
* 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).
*/
hdrlen = bpf_hdrlen(d);
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.
*/
#ifdef COMPAT_FREEBSD32
if (d->bd_compat32)
curlen = BPF_WORDALIGN32(d->bd_slen);
else
#endif
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);
counter_u64_add(d->bd_dcount, 1);
return;
}
KASSERT(!d->bd_hbuf_in_use, ("hold buffer is in use"));
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;
caplen = totlen - hdrlen;
tstype = d->bd_tstamp;
do_timestamp = tstype != BPF_T_NONE;
#ifndef BURN_BRIDGES
if (tstype == BPF_T_NONE || BPF_T_FORMAT(tstype) == BPF_T_MICROTIME) {
struct bpf_ts ts;
if (do_timestamp)
bpf_bintime2ts(bt, &ts, tstype);
#ifdef COMPAT_FREEBSD32
if (d->bd_compat32) {
bzero(&hdr32_old, sizeof(hdr32_old));
if (do_timestamp) {
hdr32_old.bh_tstamp.tv_sec = ts.bt_sec;
hdr32_old.bh_tstamp.tv_usec = ts.bt_frac;
}
hdr32_old.bh_datalen = pktlen;
hdr32_old.bh_hdrlen = hdrlen;
hdr32_old.bh_caplen = caplen;
bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr32_old,
sizeof(hdr32_old));
goto copy;
}
#endif
bzero(&hdr_old, sizeof(hdr_old));
if (do_timestamp) {
hdr_old.bh_tstamp.tv_sec = ts.bt_sec;
hdr_old.bh_tstamp.tv_usec = ts.bt_frac;
}
hdr_old.bh_datalen = pktlen;
hdr_old.bh_hdrlen = hdrlen;
hdr_old.bh_caplen = caplen;
bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr_old,
sizeof(hdr_old));
goto copy;
}
#endif
/*
* 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));
if (do_timestamp)
bpf_bintime2ts(bt, &hdr.bh_tstamp, tstype);
hdr.bh_datalen = pktlen;
hdr.bh_hdrlen = hdrlen;
hdr.bh_caplen = caplen;
bpf_append_bytes(d, d->bd_sbuf, curlen, &hdr, sizeof(hdr));
/*
* Copy the packet data into the store buffer and update its length.
*/
#ifndef BURN_BRIDGES
copy:
#endif
(*cpfn)(d, d->bd_sbuf, curlen + hdrlen, pkt, 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
bpfd_free(epoch_context_t ctx)
{
struct bpf_d *d;
struct bpf_program_buffer *p;
/*
* 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.
*/
d = __containerof(ctx, struct bpf_d, epoch_ctx);
bpf_free(d);
if (d->bd_rfilter != NULL) {
p = __containerof((void *)d->bd_rfilter,
struct bpf_program_buffer, buffer);
#ifdef BPF_JITTER
p->func = d->bd_bfilter;
#endif
bpf_program_buffer_free(&p->epoch_ctx);
}
if (d->bd_wfilter != NULL) {
p = __containerof((void *)d->bd_wfilter,
struct bpf_program_buffer, buffer);
#ifdef BPF_JITTER
p->func = NULL;
#endif
bpf_program_buffer_free(&p->epoch_ctx);
}
mtx_destroy(&d->bd_lock);
counter_u64_free(d->bd_rcount);
counter_u64_free(d->bd_dcount);
counter_u64_free(d->bd_fcount);
counter_u64_free(d->bd_wcount);
counter_u64_free(d->bd_wfcount);
counter_u64_free(d->bd_wdcount);
counter_u64_free(d->bd_zcopy);
free(d, M_BPF);
}
/*
* 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;
KASSERT(*driverp == NULL,
("bpfattach2: driverp already initialized"));
bp = malloc(sizeof(*bp), M_BPF, M_WAITOK | M_ZERO);
CK_LIST_INIT(&bp->bif_dlist);
CK_LIST_INIT(&bp->bif_wlist);
bp->bif_ifp = ifp;
bp->bif_dlt = dlt;
bp->bif_hdrlen = hdrlen;
bp->bif_bpf = driverp;
bp->bif_refcnt = 1;
*driverp = bp;
/*
* Reference ifnet pointer, so it won't freed until
* we release it.
*/
if_ref(ifp);
BPF_LOCK();
CK_LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next);
BPF_UNLOCK();
if (bootverbose && IS_DEFAULT_VNET(curvnet))
if_printf(ifp, "bpf attached\n");
}
#ifdef VIMAGE
/*
* When moving interfaces between vnet instances we need a way to
* query the dlt and hdrlen before detach so we can re-attch the if_bpf
* after the vmove. We unfortunately have no device driver infrastructure
* to query the interface for these values after creation/attach, thus
* add this as a workaround.
*/
int
bpf_get_bp_params(struct bpf_if *bp, u_int *bif_dlt, u_int *bif_hdrlen)
{
if (bp == NULL)
return (ENXIO);
if (bif_dlt == NULL && bif_hdrlen == NULL)
return (0);
if (bif_dlt != NULL)
*bif_dlt = bp->bif_dlt;
if (bif_hdrlen != NULL)
*bif_hdrlen = bp->bif_hdrlen;
return (0);
}
#endif
/*
* Detach bpf from an interface. This involves detaching each descriptor
* associated with the interface. 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, *bp_temp;
struct bpf_d *d;
BPF_LOCK();
/* Find all bpf_if struct's which reference ifp and detach them. */
CK_LIST_FOREACH_SAFE(bp, &bpf_iflist, bif_next, bp_temp) {
if (ifp != bp->bif_ifp)
continue;
CK_LIST_REMOVE(bp, bif_next);
*bp->bif_bpf = (struct bpf_if *)&dead_bpf_if;
CTR4(KTR_NET,
"%s: sheduling free for encap %d (%p) for if %p",
__func__, bp->bif_dlt, bp, ifp);
/* Detach common descriptors */
while ((d = CK_LIST_FIRST(&bp->bif_dlist)) != NULL) {
bpf_detachd_locked(d, true);
}
/* Detach writer-only descriptors */
while ((d = CK_LIST_FIRST(&bp->bif_wlist)) != NULL) {
bpf_detachd_locked(d, true);
}
bpfif_rele(bp);
}
BPF_UNLOCK();
}
/*
* Get a list of available data link type of the interface.
*/
static int
bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
{
struct ifnet *ifp;
struct bpf_if *bp;
u_int *lst;
int error, n, n1;
BPF_LOCK_ASSERT();
ifp = d->bd_bif->bif_ifp;
n1 = 0;
CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp == ifp)
n1++;
}
if (bfl->bfl_list == NULL) {
bfl->bfl_len = n1;
return (0);
}
if (n1 > bfl->bfl_len)
return (ENOMEM);
lst = malloc(n1 * sizeof(u_int), M_TEMP, M_WAITOK);
n = 0;
CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp != ifp)
continue;
lst[n++] = bp->bif_dlt;
}
error = copyout(lst, bfl->bfl_list, sizeof(u_int) * n);
free(lst, M_TEMP);
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;
BPF_LOCK_ASSERT();
MPASS(d->bd_bif != NULL);
/*
* It is safe to check bd_bif without BPFD_LOCK, it can not be
* changed while we hold global lock.
*/
if (d->bd_bif->bif_dlt == dlt)
return (0);
ifp = d->bd_bif->bif_ifp;
CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
if (bp->bif_ifp == ifp && bp->bif_dlt == dlt)
break;
}
if (bp == NULL)
return (EINVAL);
opromisc = d->bd_promisc;
bpf_attachd(d, bp);
if (opromisc) {
error = ifpromisc(bp->bif_ifp, 1);
if (error)
if_printf(bp->bif_ifp, "%s: ifpromisc failed (%d)\n",
__func__, error);
else
d->bd_promisc = 1;
}
return (0);
}
static void
bpf_drvinit(void *unused)
{
struct cdev *dev;
sx_init(&bpf_sx, "bpf global lock");
CK_LIST_INIT(&bpf_iflist);
dev = make_dev(&bpf_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "bpf");
/* For compatibility */
make_dev_alias(dev, "bpf0");
}
/*
* Zero out the various packet counters associated with all of the bpf
* descriptors. At some point, we will probably want to get a bit more
* granular and allow the user to specify descriptors to be zeroed.
*/
static void
bpf_zero_counters(void)
{
struct bpf_if *bp;
struct bpf_d *bd;
BPF_LOCK();
/*
* We are protected by global lock here, interfaces and
* descriptors can not be deleted while we hold it.
*/
CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
CK_LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
counter_u64_zero(bd->bd_rcount);
counter_u64_zero(bd->bd_dcount);
counter_u64_zero(bd->bd_fcount);
counter_u64_zero(bd->bd_wcount);
counter_u64_zero(bd->bd_wfcount);
counter_u64_zero(bd->bd_zcopy);
}
}
BPF_UNLOCK();
}
/*
* Fill filter statistics
*/
static void
bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd)
{
BPF_LOCK_ASSERT();
bzero(d, sizeof(*d));
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 = counter_u64_fetch(bd->bd_rcount);
d->bd_dcount = counter_u64_fetch(bd->bd_dcount);
d->bd_fcount = counter_u64_fetch(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 = counter_u64_fetch(bd->bd_wcount);
d->bd_wdcount = counter_u64_fetch(bd->bd_wdcount);
d->bd_wfcount = counter_u64_fetch(bd->bd_wfcount);
d->bd_zcopy = counter_u64_fetch(bd->bd_zcopy);
d->bd_bufmode = bd->bd_bufmode;
}
/*
* Handle `netstat -B' stats request
*/
static int
bpf_stats_sysctl(SYSCTL_HANDLER_ARGS)
{
static const struct xbpf_d zerostats;
struct xbpf_d *xbdbuf, *xbd, tempstats;
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);
/*
* Check to see if the user is requesting that the counters be
* zeroed out. Explicitly check that the supplied data is zeroed,
* as we aren't allowing the user to set the counters currently.
*/
if (req->newptr != NULL) {
if (req->newlen != sizeof(tempstats))
return (EINVAL);
memset(&tempstats, 0, sizeof(tempstats));
error = SYSCTL_IN(req, &tempstats, sizeof(tempstats));
if (error)
return (error);
if (bcmp(&tempstats, &zerostats, sizeof(tempstats)) != 0)
return (EINVAL);
bpf_zero_counters();
return (0);
}
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);
BPF_LOCK();
if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) {
BPF_UNLOCK();
free(xbdbuf, M_BPF);
return (ENOMEM);
}
index = 0;
CK_LIST_FOREACH(bp, &bpf_iflist, bif_next) {
/* Send writers-only first */
CK_LIST_FOREACH(bd, &bp->bif_wlist, bd_next) {
xbd = &xbdbuf[index++];
bpfstats_fill_xbpf(xbd, bd);
}
CK_LIST_FOREACH(bd, &bp->bif_dlist, bd_next) {
xbd = &xbdbuf[index++];
bpfstats_fill_xbpf(xbd, bd);
}
}
BPF_UNLOCK();
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.
*/
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 = (struct bpf_if *)&dead_bpf_if;
}
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 */
#ifdef DDB
static void
bpf_show_bpf_if(struct bpf_if *bpf_if)
{
if (bpf_if == NULL)
return;
db_printf("%p:\n", bpf_if);
#define BPF_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, bpf_if->e);
/* bif_ext.bif_next */
/* bif_ext.bif_dlist */
BPF_DB_PRINTF("%#x", bif_dlt);
BPF_DB_PRINTF("%u", bif_hdrlen);
/* bif_wlist */
BPF_DB_PRINTF("%p", bif_ifp);
BPF_DB_PRINTF("%p", bif_bpf);
BPF_DB_PRINTF("%u", bif_refcnt);
}
DB_SHOW_COMMAND(bpf_if, db_show_bpf_if)
{
if (!have_addr) {
db_printf("usage: show bpf_if <struct bpf_if *>\n");
return;
}
bpf_show_bpf_if((struct bpf_if *)addr);
}
#endif
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