freebsd-dev/contrib/libpcap/pcap-pf.c

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/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
1997-05-27 00:01:12 +00:00
*
* packet filter subroutines for tcpdump
* Extraction/creation by Jeffrey Mogul, DECWRL
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
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#endif
#include <sys/types.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <net/pfilt.h>
struct mbuf;
struct rtentry;
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
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* Make "pcap.h" not include "pcap/bpf.h"; we are going to include the
* native OS version, as we need various BPF ioctls from it.
*/
#define PCAP_DONT_INCLUDE_PCAP_BPF_H
#include <net/bpf.h>
#include "pcap-int.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
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/*
* FDDI packets are padded to make everything line up on a nice boundary.
*/
#define PCAP_FDDIPAD 3
/*
* Private data for capturing on Ultrix and DEC OSF/1^WDigital UNIX^W^W
* Tru64 UNIX packetfilter devices.
*/
struct pcap_pf {
int filtering_in_kernel; /* using kernel filter */
u_long TotPkts; /* can't oflow for 79 hrs on ether */
u_long TotAccepted; /* count accepted by filter */
u_long TotDrops; /* count of dropped packets */
long TotMissed; /* missed by i/f during this run */
long OrigMissed; /* missed by i/f before this run */
};
static int pcap_setfilter_pf(pcap_t *, struct bpf_program *);
/*
* BUFSPACE is the size in bytes of the packet read buffer. Most tcpdump
* applications aren't going to need more than 200 bytes of packet header
* and the read shouldn't return more packets than packetfilter's internal
* queue limit (bounded at 256).
*/
#define BUFSPACE (200 * 256)
static int
pcap_read_pf(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
{
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struct pcap_pf *pf = pc->priv;
register u_char *p, *bp;
register int cc, n, buflen, inc;
register struct enstamp *sp;
#ifdef LBL_ALIGN
struct enstamp stamp;
#endif
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register u_int pad;
again:
cc = pc->cc;
if (cc == 0) {
cc = read(pc->fd, (char *)pc->buffer + pc->offset, pc->bufsize);
if (cc < 0) {
if (errno == EWOULDBLOCK)
return (0);
if (errno == EINVAL &&
lseek(pc->fd, 0L, SEEK_CUR) + pc->bufsize < 0) {
/*
* Due to a kernel bug, after 2^31 bytes,
* the kernel file offset overflows and
* read fails with EINVAL. The lseek()
* to 0 will fix things.
*/
(void)lseek(pc->fd, 0L, SEEK_SET);
goto again;
}
pcap_fmt_errmsg_for_errno(pc->errbuf,
sizeof(pc->errbuf), errno, "pf read");
return (-1);
}
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bp = (u_char *)pc->buffer + pc->offset;
} else
bp = pc->bp;
/*
* Loop through each packet.
*/
n = 0;
pad = pc->fddipad;
while (cc > 0) {
/*
* Has "pcap_breakloop()" been called?
* If so, return immediately - if we haven't read any
* packets, clear the flag and return -2 to indicate
* that we were told to break out of the loop, otherwise
* leave the flag set, so that the *next* call will break
* out of the loop without having read any packets, and
* return the number of packets we've processed so far.
*/
if (pc->break_loop) {
if (n == 0) {
pc->break_loop = 0;
return (-2);
} else {
pc->cc = cc;
pc->bp = bp;
return (n);
}
}
if (cc < sizeof(*sp)) {
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pcap_snprintf(pc->errbuf, sizeof(pc->errbuf),
"pf short read (%d)", cc);
return (-1);
}
#ifdef LBL_ALIGN
if ((long)bp & 3) {
sp = &stamp;
memcpy((char *)sp, (char *)bp, sizeof(*sp));
} else
#endif
sp = (struct enstamp *)bp;
if (sp->ens_stamplen != sizeof(*sp)) {
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pcap_snprintf(pc->errbuf, sizeof(pc->errbuf),
"pf short stamplen (%d)",
sp->ens_stamplen);
return (-1);
}
p = bp + sp->ens_stamplen;
buflen = sp->ens_count;
if (buflen > pc->snapshot)
buflen = pc->snapshot;
/* Calculate inc before possible pad update */
inc = ENALIGN(buflen + sp->ens_stamplen);
cc -= inc;
bp += inc;
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pf->TotPkts++;
pf->TotDrops += sp->ens_dropped;
pf->TotMissed = sp->ens_ifoverflows;
if (pf->OrigMissed < 0)
pf->OrigMissed = pf->TotMissed;
/*
* Short-circuit evaluation: if using BPF filter
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* in kernel, no need to do it now - we already know
* the packet passed the filter.
*
* Note: the filter code was generated assuming
* that pc->fddipad was the amount of padding
* before the header, as that's what's required
* in the kernel, so we run the filter before
* skipping that padding.
*/
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if (pf->filtering_in_kernel ||
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bpf_filter(pc->fcode.bf_insns, p, sp->ens_count, buflen)) {
struct pcap_pkthdr h;
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pf->TotAccepted++;
h.ts = sp->ens_tstamp;
h.len = sp->ens_count - pad;
p += pad;
buflen -= pad;
h.caplen = buflen;
(*callback)(user, &h, p);
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if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
pc->cc = cc;
pc->bp = bp;
return (n);
}
}
}
pc->cc = 0;
return (n);
}
static int
pcap_inject_pf(pcap_t *p, const void *buf, size_t size)
{
int ret;
ret = write(p->fd, buf, size);
if (ret == -1) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "send");
return (-1);
}
return (ret);
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}
static int
pcap_stats_pf(pcap_t *p, struct pcap_stat *ps)
{
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struct pcap_pf *pf = p->priv;
/*
* If packet filtering is being done in the kernel:
*
* "ps_recv" counts only packets that passed the filter.
* This does not include packets dropped because we
* ran out of buffer space. (XXX - perhaps it should,
* by adding "ps_drop" to "ps_recv", for compatibility
* with some other platforms. On the other hand, on
* some platforms "ps_recv" counts only packets that
* passed the filter, and on others it counts packets
* that didn't pass the filter....)
*
* "ps_drop" counts packets that passed the kernel filter
* (if any) but were dropped because the input queue was
* full.
*
* "ps_ifdrop" counts packets dropped by the network
* inteface (regardless of whether they would have passed
* the input filter, of course).
*
* If packet filtering is not being done in the kernel:
*
* "ps_recv" counts only packets that passed the filter.
*
* "ps_drop" counts packets that were dropped because the
* input queue was full, regardless of whether they passed
* the userland filter.
*
* "ps_ifdrop" counts packets dropped by the network
* inteface (regardless of whether they would have passed
* the input filter, of course).
*
* These statistics don't include packets not yet read from
* the kernel by libpcap, but they may include packets not
* yet read from libpcap by the application.
*/
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ps->ps_recv = pf->TotAccepted;
ps->ps_drop = pf->TotDrops;
ps->ps_ifdrop = pf->TotMissed - pf->OrigMissed;
return (0);
}
/*
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* We include the OS's <net/bpf.h>, not our "pcap/bpf.h", so we probably
* don't get DLT_DOCSIS defined.
*/
#ifndef DLT_DOCSIS
#define DLT_DOCSIS 143
#endif
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static int
pcap_activate_pf(pcap_t *p)
{
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struct pcap_pf *pf = p->priv;
short enmode;
int backlog = -1; /* request the most */
struct enfilter Filter;
struct endevp devparams;
int err;
/*
* Initially try a read/write open (to allow the inject
* method to work). If that fails due to permission
* issues, fall back to read-only. This allows a
* non-root user to be granted specific access to pcap
* capabilities via file permissions.
*
* XXX - we should have an API that has a flag that
* controls whether to open read-only or read-write,
* so that denial of permission to send (or inability
* to send, if sending packets isn't supported on
* the device in question) can be indicated at open
* time.
*
* XXX - we assume here that "pfopen()" does not, in fact, modify
* its argument, even though it takes a "char *" rather than a
* "const char *" as its first argument. That appears to be
* the case, at least on Digital UNIX 4.0.
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*
* XXX - is there an error that means "no such device"? Is
* there one that means "that device doesn't support pf"?
*/
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p->fd = pfopen(p->opt.device, O_RDWR);
if (p->fd == -1 && errno == EACCES)
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p->fd = pfopen(p->opt.device, O_RDONLY);
if (p->fd < 0) {
if (errno == EACCES) {
pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"pf open: %s: Permission denied\n"
"your system may not be properly configured; see the packetfilter(4) man page",
p->opt.device);
err = PCAP_ERROR_PERM_DENIED;
} else {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "pf open: %s", p->opt.device);
err = PCAP_ERROR;
}
goto bad;
}
/*
* Turn a negative snapshot value (invalid), a snapshot value of
* 0 (unspecified), or a value bigger than the normal maximum
* value, into the maximum allowed value.
*
* If some application really *needs* a bigger snapshot
* length, we should just increase MAXIMUM_SNAPLEN.
*/
if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
p->snapshot = MAXIMUM_SNAPLEN;
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pf->OrigMissed = -1;
enmode = ENTSTAMP|ENNONEXCL;
if (!p->opt.immediate)
enmode |= ENBATCH;
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if (p->opt.promisc)
enmode |= ENPROMISC;
if (ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCMBIS");
err = PCAP_ERROR;
goto bad;
}
#ifdef ENCOPYALL
/* Try to set COPYALL mode so that we see packets to ourself */
enmode = ENCOPYALL;
(void)ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode);/* OK if this fails */
#endif
/* set the backlog */
if (ioctl(p->fd, EIOCSETW, (caddr_t)&backlog) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCSETW");
err = PCAP_ERROR;
goto bad;
}
/* discover interface type */
if (ioctl(p->fd, EIOCDEVP, (caddr_t)&devparams) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCDEVP");
err = PCAP_ERROR;
goto bad;
}
/* HACK: to compile prior to Ultrix 4.2 */
#ifndef ENDT_FDDI
#define ENDT_FDDI 4
#endif
switch (devparams.end_dev_type) {
case ENDT_10MB:
p->linktype = DLT_EN10MB;
p->offset = 2;
/*
* This is (presumably) a real Ethernet capture; give it a
* link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
* that an application can let you choose it, in case you're
* capturing DOCSIS traffic that a Cisco Cable Modem
* Termination System is putting out onto an Ethernet (it
* doesn't put an Ethernet header onto the wire, it puts raw
* DOCSIS frames out on the wire inside the low-level
* Ethernet framing).
*/
p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
/*
* If that fails, just leave the list empty.
*/
if (p->dlt_list != NULL) {
p->dlt_list[0] = DLT_EN10MB;
p->dlt_list[1] = DLT_DOCSIS;
p->dlt_count = 2;
}
break;
case ENDT_FDDI:
p->linktype = DLT_FDDI;
break;
#ifdef ENDT_SLIP
case ENDT_SLIP:
p->linktype = DLT_SLIP;
break;
#endif
#ifdef ENDT_PPP
case ENDT_PPP:
p->linktype = DLT_PPP;
break;
#endif
#ifdef ENDT_LOOPBACK
case ENDT_LOOPBACK:
/*
* It appears to use Ethernet framing, at least on
* Digital UNIX 4.0.
*/
p->linktype = DLT_EN10MB;
p->offset = 2;
break;
#endif
#ifdef ENDT_TRN
case ENDT_TRN:
p->linktype = DLT_IEEE802;
break;
#endif
default:
/*
* XXX - what about ENDT_IEEE802? The pfilt.h header
* file calls this "IEEE 802 networks (non-Ethernet)",
* but that doesn't specify a specific link layer type;
* it could be 802.4, or 802.5 (except that 802.5 is
* ENDT_TRN), or 802.6, or 802.11, or.... That's why
* DLT_IEEE802 was hijacked to mean Token Ring in various
* BSDs, and why we went along with that hijacking.
*
* XXX - what about ENDT_HDLC and ENDT_NULL?
* Presumably, as ENDT_OTHER is just "Miscellaneous
* framing", there's not much we can do, as that
* doesn't specify a particular type of header.
*/
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pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
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"unknown data-link type %u", devparams.end_dev_type);
err = PCAP_ERROR;
goto bad;
}
/* set truncation */
if (p->linktype == DLT_FDDI) {
p->fddipad = PCAP_FDDIPAD;
/* packetfilter includes the padding in the snapshot */
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p->snapshot += PCAP_FDDIPAD;
} else
p->fddipad = 0;
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if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&p->snapshot) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCTRUNCATE");
err = PCAP_ERROR;
goto bad;
}
/* accept all packets */
memset(&Filter, 0, sizeof(Filter));
Filter.enf_Priority = 37; /* anything > 2 */
Filter.enf_FilterLen = 0; /* means "always true" */
if (ioctl(p->fd, EIOCSETF, (caddr_t)&Filter) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCSETF");
err = PCAP_ERROR;
goto bad;
}
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if (p->opt.timeout != 0) {
struct timeval timeout;
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timeout.tv_sec = p->opt.timeout / 1000;
timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
if (ioctl(p->fd, EIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "EIOCSRTIMEOUT");
err = PCAP_ERROR;
goto bad;
}
}
p->bufsize = BUFSPACE;
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p->buffer = malloc(p->bufsize + p->offset);
if (p->buffer == NULL) {
pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "malloc");
err = PCAP_ERROR;
goto bad;
}
/*
* "select()" and "poll()" work on packetfilter devices.
*/
p->selectable_fd = p->fd;
p->read_op = pcap_read_pf;
p->inject_op = pcap_inject_pf;
p->setfilter_op = pcap_setfilter_pf;
p->setdirection_op = NULL; /* Not implemented. */
p->set_datalink_op = NULL; /* can't change data link type */
p->getnonblock_op = pcap_getnonblock_fd;
p->setnonblock_op = pcap_setnonblock_fd;
p->stats_op = pcap_stats_pf;
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return (0);
bad:
Update libpcap to 1.1.1. Changes: Thu. April 1, 2010. guy@alum.mit.edu. Summary for 1.1.1 libpcap release Update CHANGES to reflect more of the changes in 1.1.0. Fix build on RHEL5. Fix shared library build on AIX. Thu. March 11, 2010. ken@netfunctional.ca/guy@alum.mit.edu. Summary for 1.1.0 libpcap release Add SocketCAN capture support Add Myricom SNF API support Update Endace DAG and ERF support Add support for shared libraries on Solaris, HP-UX, and AIX Build, install, and un-install shared libraries by default; don't build/install shared libraries on platforms we don't support Fix building from a directory other than the source directory Fix compiler warnings and builds on some platforms Update config.guess and config.sub Support monitor mode on mac80211 devices on Linux Fix USB memory-mapped capturing on Linux; it requires a new DLT_ value On Linux, scan /sys/class/net for devices if we have it; scan it, or /proc/net/dev if we don't have /sys/class/net, even if we have getifaddrs(), as it'll find interfaces with no addresses Add limited support for reading pcap-ng files Fix BPF driver-loading error handling on AIX Support getting the full-length interface description on FreeBSD In the lexical analyzer, free up any addrinfo structure we got back from getaddrinfo(). Add support for BPF and libdlpi in OpenSolaris (and SXCE) Hyphenate "link-layer" everywhere Add /sys/kernel/debug/usb/usbmon to the list of usbmon locations In pcap_read_linux_mmap(), if there are no frames available, call poll() even if we're in non-blocking mode, so we pick up errors, and check for the errors in question. Note that poll() works on BPF devices is Snow Leopard If an ENXIO or ENETDOWN is received, it may mean the device has gone away. Deal with it. For BPF, raise the default capture buffer size to from 32k to 512k Support ps_ifdrop on Linux Added a bunch of #ifdef directives to make wpcap.dll (WinPcap) compile under cygwin. Changes to Linux mmapped captures. Fix bug where create_ring would fail for particular snaplen and buffer size combinations Update pcap-config so that it handles libpcap requiring additional libraries Add workaround for threadsafeness on Windows Add missing mapping for DLT_ENC <-> LINKTYPE_ENC DLT: Add DLT_CAN_SOCKETCAN DLT: Add Solaris ipnet Don't check for DLT_IPNET if it's not defined Add link-layer types for Fibre Channel FC-2 Add link-layer types for Wireless HART Add link-layer types for AOS Add link-layer types for DECT Autoconf fixes (AIX, HP-UX, OSF/1, Tru64 cleanups) Install headers unconditionally, and include vlan.h/bluetooth.h if enabled Autoconf fixes+cleanup Support enabling/disabling bluetooth (--{en,dis}able-bluetooth) Support disabling SITA support (--without-sita) Return -1 on failure to create packet ring (if supported but creation failed) Fix handling of 'any' device, so that it can be opened, and no longer attempt to open it in Monitor mode Add support for snapshot length for USB Memory-Mapped Interface Fix configure and build on recent Linux kernels Fix memory-mapped Linux capture to support pcap_next() and pcap_next_ex() Fixes for Linux USB capture DLT: Add DLT_LINUX_EVDEV DLT: Add DLT_GSMTAP_UM DLT: Add DLT_GSMTAP_ABIS
2010-10-28 16:22:13 +00:00
pcap_cleanup_live_common(p);
return (err);
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}
pcap_t *
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pcap_create_interface(const char *device _U_, char *ebuf)
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{
pcap_t *p;
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p = pcap_create_common(ebuf, sizeof (struct pcap_pf));
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if (p == NULL)
return (NULL);
p->activate_op = pcap_activate_pf;
return (p);
}
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/*
* XXX - is there an error from pfopen() that means "no such device"?
* Is there one that means "that device doesn't support pf"?
*/
static int
can_be_bound(const char *name _U_)
{
return (1);
}
static int
get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
{
/*
* Nothing we can do other than mark loopback devices as "the
* connected/disconnected status doesn't apply".
*
* XXX - is there a way to find out whether an adapter has
* something plugged into it?
*/
if (*flags & PCAP_IF_LOOPBACK) {
/*
* Loopback devices aren't wireless, and "connected"/
* "disconnected" doesn't apply to them.
*/
*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
return (0);
}
return (0);
}
int
pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
{
return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
get_if_flags));
}
static int
pcap_setfilter_pf(pcap_t *p, struct bpf_program *fp)
{
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struct pcap_pf *pf = p->priv;
struct bpf_version bv;
/*
* See if BIOCVERSION works. If not, we assume the kernel doesn't
* support BPF-style filters (it's not documented in the bpf(7)
* or packetfiler(7) man pages, but the code used to fail if
* BIOCSETF worked but BIOCVERSION didn't, and I've seen it do
* kernel filtering in DU 4.0, so presumably BIOCVERSION works
* there, at least).
*/
if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) >= 0) {
/*
* OK, we have the version of the BPF interpreter;
* is it the same major version as us, and the same
* or better minor version?
*/
if (bv.bv_major == BPF_MAJOR_VERSION &&
bv.bv_minor >= BPF_MINOR_VERSION) {
/*
* Yes. Try to install the filter.
*/
if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
pcap_fmt_errmsg_for_errno(p->errbuf,
sizeof(p->errbuf), errno, "BIOCSETF");
return (-1);
}
/*
* OK, that succeeded. We're doing filtering in
* the kernel. (We assume we don't have a
* userland filter installed - that'd require
* a previous version check to have failed but
* this one to succeed.)
*
* XXX - this message should be supplied to the
* application as a warning of some sort,
* except that if it's a GUI application, it's
* not clear that it should be displayed in
* a window to annoy the user.
*/
fprintf(stderr, "tcpdump: Using kernel BPF filter\n");
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pf->filtering_in_kernel = 1;
/*
* Discard any previously-received packets,
* as they might have passed whatever filter
* was formerly in effect, but might not pass
* this filter (BIOCSETF discards packets buffered
* in the kernel, so you can lose packets in any
* case).
*/
p->cc = 0;
return (0);
}
/*
* We can't use the kernel's BPF interpreter; don't give
* up, just log a message and be inefficient.
*
* XXX - this should really be supplied to the application
* as a warning of some sort.
*/
fprintf(stderr,
"tcpdump: Requires BPF language %d.%d or higher; kernel is %d.%d\n",
BPF_MAJOR_VERSION, BPF_MINOR_VERSION,
bv.bv_major, bv.bv_minor);
}
/*
* We couldn't do filtering in the kernel; do it in userland.
*/
if (install_bpf_program(p, fp) < 0)
return (-1);
/*
* XXX - this message should be supplied by the application as
* a warning of some sort.
*/
fprintf(stderr, "tcpdump: Filtering in user process\n");
2015-01-06 18:58:31 +00:00
pf->filtering_in_kernel = 0;
return (0);
}
/*
* Libpcap version string.
*/
const char *
pcap_lib_version(void)
{
return (PCAP_VERSION_STRING);
}