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libpcap/pcap-bpf.c

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/*
* Copyright (c) 1993, 1994, 1995, 1996, 1998
* 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.
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.104 2008-04-04 19:37:45 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/param.h> /* optionally get BSD define */
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <net/if.h>
#ifdef _AIX
/*
* Make "pcap.h" not include "pcap/bpf.h"; we are going to include the
* native OS version, as we need "struct bpf_config" from it.
*/
#define PCAP_DONT_INCLUDE_PCAP_BPF_H
#include <sys/types.h>
/*
* Prevent bpf.h from redefining the DLT_ values to their
* IFT_ values, as we're going to return the standard libpcap
* values, not IBM's non-standard IFT_ values.
*/
#undef _AIX
#include <net/bpf.h>
#define _AIX
#include <net/if_types.h> /* for IFT_ values */
#include <sys/sysconfig.h>
#include <sys/device.h>
#include <sys/cfgodm.h>
#include <cf.h>
#ifdef __64BIT__
#define domakedev makedev64
#define getmajor major64
#define bpf_hdr bpf_hdr32
#else /* __64BIT__ */
#define domakedev makedev
#define getmajor major
#endif /* __64BIT__ */
#define BPF_NAME "bpf"
#define BPF_MINORS 4
#define DRIVER_PATH "/usr/lib/drivers"
#define BPF_NODE "/dev/bpf"
static int bpfloadedflag = 0;
static int odmlockid = 0;
#else /* _AIX */
#include <net/bpf.h>
#endif /* _AIX */
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef HAVE_NET_IF_MEDIA_H
# include <net/if_media.h>
#endif
#include "pcap-int.h"
#ifdef HAVE_DAG_API
#include "pcap-dag.h"
#endif /* HAVE_DAG_API */
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#ifdef BIOCGDLTLIST
# if (defined(HAVE_NET_IF_MEDIA_H) && defined(IFM_IEEE80211)) && !defined(__APPLE__)
#define HAVE_BSD_IEEE80211
# endif
# if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)
static int find_802_11(struct bpf_dltlist *);
# ifdef HAVE_BSD_IEEE80211
static int monitor_mode(pcap_t *, int);
# endif
# if defined(__APPLE__)
static void remove_en(pcap_t *);
static void remove_802_11(pcap_t *);
# endif
# endif /* defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) */
#endif /* BIOCGDLTLIST */
/*
* 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
/*
* On OS X, we don't even get any of the 802.11-plus-radio-header DLT_'s
* defined, even though some of them are used by various Airport drivers.
*/
#ifndef DLT_PRISM_HEADER
#define DLT_PRISM_HEADER 119
#endif
#ifndef DLT_AIRONET_HEADER
#define DLT_AIRONET_HEADER 120
#endif
#ifndef DLT_IEEE802_11_RADIO
#define DLT_IEEE802_11_RADIO 127
#endif
#ifndef DLT_IEEE802_11_RADIO_AVS
#define DLT_IEEE802_11_RADIO_AVS 163
#endif
static int pcap_can_set_rfmon_bpf(pcap_t *p);
static int pcap_activate_bpf(pcap_t *p);
static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp);
static int pcap_setdirection_bpf(pcap_t *, pcap_direction_t);
static int pcap_set_datalink_bpf(pcap_t *p, int dlt);
pcap_t *
pcap_create(const char *device, char *ebuf)
{
pcap_t *p;
#ifdef HAVE_DAG_API
if (strstr(device, "dag"))
return (dag_create(device, ebuf));
#endif /* HAVE_DAG_API */
p = pcap_create_common(device, ebuf);
if (p == NULL)
return (NULL);
p->activate_op = pcap_activate_bpf;
p->can_set_rfmon_op = pcap_can_set_rfmon_bpf;
return (p);
}
static int
bpf_open(pcap_t *p)
{
int fd;
#ifdef HAVE_CLONING_BPF
static const char device[] = "/dev/bpf";
#else
int n = 0;
char device[sizeof "/dev/bpf0000000000"];
#endif
#ifdef _AIX
/*
* Load the bpf driver, if it isn't already loaded,
* and create the BPF device entries, if they don't
* already exist.
*/
if (bpf_load(p->errbuf) == -1)
return (-1);
#endif
#ifdef HAVE_CLONING_BPF
if ((fd = open(device, O_RDWR)) == -1 &&
(errno != EACCES || (fd = open(device, O_RDONLY)) == -1))
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"(cannot open device) %s: %s", device, pcap_strerror(errno));
#else
/*
* Go through all the minors and find one that isn't in use.
*/
do {
(void)snprintf(device, sizeof(device), "/dev/bpf%d", n++);
/*
* 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.
*/
fd = open(device, O_RDWR);
if (fd == -1 && errno == EACCES)
fd = open(device, O_RDONLY);
} while (fd < 0 && errno == EBUSY);
/*
* XXX better message for all minors used
*/
if (fd < 0)
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s",
device, pcap_strerror(errno));
#endif
return (fd);
}
#ifdef BIOCGDLTLIST
static int
get_dlt_list(int fd, int v, struct bpf_dltlist *bdlp, char *ebuf)
{
memset(bdlp, 0, sizeof(*bdlp));
if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) == 0) {
u_int i;
int is_ethernet;
bdlp->bfl_list = (u_int *) malloc(sizeof(u_int) * (bdlp->bfl_len + 1));
if (bdlp->bfl_list == NULL) {
(void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
pcap_strerror(errno));
return (-1);
}
if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) < 0) {
(void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
"BIOCGDLTLIST: %s", pcap_strerror(errno));
free(bdlp->bfl_list);
return (-1);
}
/*
* OK, for real Ethernet devices, add DLT_DOCSIS to the
* list, 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).
*
* A "real Ethernet device" is defined here as a device
* that has a link-layer type of DLT_EN10MB and that has
* no alternate link-layer types; that's done to exclude
* 802.11 interfaces (which might or might not be the
* right thing to do, but I suspect it is - Ethernet <->
* 802.11 bridges would probably badly mishandle frames
* that don't have Ethernet headers).
*/
if (v == DLT_EN10MB) {
is_ethernet = 1;
for (i = 0; i < bdlp->bfl_len; i++) {
if (bdlp->bfl_list[i] != DLT_EN10MB) {
is_ethernet = 0;
break;
}
}
if (is_ethernet) {
/*
* We reserved one more slot at the end of
* the list.
*/
bdlp->bfl_list[bdlp->bfl_len] = DLT_DOCSIS;
bdlp->bfl_len++;
}
}
} else {
/*
* EINVAL just means "we don't support this ioctl on
* this device"; don't treat it as an error.
*/
if (errno != EINVAL) {
(void)snprintf(ebuf, PCAP_ERRBUF_SIZE,
"BIOCGDLTLIST: %s", pcap_strerror(errno));
return (-1);
}
}
return (0);
}
#endif
static int
pcap_can_set_rfmon_bpf(pcap_t *p)
{
#if defined(__APPLE__)
struct utsname osinfo;
struct ifreq ifr;
int fd;
#ifdef BIOCGDLTLIST
struct bpf_dltlist bdl;
#endif
/*
* The joys of monitor mode on OS X.
*
* Prior to 10.4, it's not supported at all.
*
* In 10.4, if adapter enN supports monitor mode, there's a
* wltN adapter corresponding to it; you open it, instead of
* enN, to get monitor mode. You get whatever link-layer
* headers it supplies.
*
* In 10.5, and, we assume, later releases, if adapter enN
* supports monitor mode, it offers, among its selectable
* DLT_ values, values that let you get the 802.11 header;
* selecting one of those values puts the adapter into monitor
* mode (i.e., you can't get 802.11 headers except in monitor
* mode, and you can't get Ethernet headers in monitor mode).
*/
if (uname(&osinfo) == -1) {
/*
* Can't get the OS version; just say "no".
*/
return (0);
}
/*
* We assume osinfo.sysname is "Darwin", because
* __APPLE__ is defined. We just check the version.
*/
if (osinfo.release[0] < '8' && osinfo.release[1] == '.') {
/*
* 10.3 (Darwin 7.x) or earlier.
* Monitor mode not supported.
*/
return (0);
}
if (osinfo.release[0] == '8' && osinfo.release[1] == '.') {
/*
* 10.4 (Darwin 8.x). s/en/wlt/, and check
* whether the device exists.
*/
if (strncmp(p->opt.source, "en", 2) != 0) {
/*
* Not an enN device; no monitor mode.
*/
return (0);
}
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"socket: %s", pcap_strerror(errno));
return (PCAP_ERROR);
}
strlcpy(ifr.ifr_name, "wlt", sizeof(ifr.ifr_name));
strlcat(ifr.ifr_name, p->opt.source + 2, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
/*
* No such device?
*/
close(fd);
return (0);
}
close(fd);
return (1);
}
#ifdef BIOCGDLTLIST
/*
* Everything else is 10.5 or later; for those,
* we just open the enN device, and check whether
* we have any 802.11 devices.
*
* First, open a BPF device.
*/
fd = bpf_open(p);
if (fd < 0)
return (PCAP_ERROR);
/*
* Now bind to the device.
*/
(void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSETIF: %s: %s",
p->opt.source, pcap_strerror(errno));
close(fd);
return (PCAP_ERROR);
}
/*
* We know the default link type -- now determine all the DLTs
* this interface supports. If this fails with EINVAL, it's
* not fatal; we just don't get to use the feature later.
* (We don't care about DLT_DOCSIS, so we pass DLT_NULL
* as the default DLT for this adapter.)
*/
if (get_dlt_list(fd, DLT_NULL, &bdl, p->errbuf) == -1) {
close(fd);
return (PCAP_ERROR);
}
if (find_802_11(&bdl) != -1) {
/*
* We have an 802.11 DLT, so we can set monitor mode.
*/
free(bdl.bfl_list);
close(fd);
return (1);
}
free(bdl.bfl_list);
#endif /* BIOCGDLTLIST */
return (0);
#elif defined(HAVE_BSD_IEEE80211)
int ret;
ret = monitor_mode(p, 0);
if (ret == PCAP_ERROR_RFMON_NOTSUP)
return (0); /* not an error, just a "can't do" */
if (ret == 0)
return (1); /* success */
return (ret);
#else
return (0);
#endif
}
static int
pcap_stats_bpf(pcap_t *p, struct pcap_stat *ps)
{
struct bpf_stat s;
/*
* "ps_recv" counts packets handed to the filter, not packets
* that passed the filter. This includes packets later dropped
* because we ran out of buffer space.
*
* "ps_drop" counts packets dropped inside the BPF device
* because we ran out of buffer space. It doesn't count
* packets dropped by the interface driver. It counts
* only packets that passed the filter.
*
* Both statistics include packets not yet read from the kernel
* by libpcap, and thus not yet seen by the application.
*/
if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s",
pcap_strerror(errno));
return (-1);
}
ps->ps_recv = s.bs_recv;
ps->ps_drop = s.bs_drop;
return (0);
}
static int
pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
int cc;
int n = 0;
register u_char *bp, *ep;
u_char *datap;
#ifdef PCAP_FDDIPAD
register int pad;
#endif
again:
/*
* Has "pcap_breakloop()" been called?
*/
if (p->break_loop) {
/*
* Yes - clear the flag that indicates that it
* has, and return -2 to indicate that we were
* told to break out of the loop.
*/
p->break_loop = 0;
return (-2);
}
cc = p->cc;
if (p->cc == 0) {
cc = read(p->fd, (char *)p->buffer, p->bufsize);
if (cc < 0) {
/* Don't choke when we get ptraced */
switch (errno) {
case EINTR:
goto again;
#ifdef _AIX
case EFAULT:
/*
* Sigh. More AIX wonderfulness.
*
* For some unknown reason the uiomove()
* operation in the bpf kernel extension
* used to copy the buffer into user
* space sometimes returns EFAULT. I have
* no idea why this is the case given that
* a kernel debugger shows the user buffer
* is correct. This problem appears to
* be mostly mitigated by the memset of
* the buffer before it is first used.
* Very strange.... Shaun Clowes
*
* In any case this means that we shouldn't
* treat EFAULT as a fatal error; as we
* don't have an API for returning
* a "some packets were dropped since
* the last packet you saw" indication,
* we just ignore EFAULT and keep reading.
*/
goto again;
#endif
case EWOULDBLOCK:
return (0);
#if defined(sun) && !defined(BSD)
/*
* Due to a SunOS bug, after 2^31 bytes, the kernel
* file offset overflows and read fails with EINVAL.
* The lseek() to 0 will fix things.
*/
case EINVAL:
if (lseek(p->fd, 0L, SEEK_CUR) +
p->bufsize < 0) {
(void)lseek(p->fd, 0L, SEEK_SET);
goto again;
}
/* fall through */
#endif
}
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s",
pcap_strerror(errno));
return (-1);
}
bp = p->buffer;
} else
bp = p->bp;
/*
* Loop through each packet.
*/
#define bhp ((struct bpf_hdr *)bp)
ep = bp + cc;
#ifdef PCAP_FDDIPAD
pad = p->fddipad;
#endif
while (bp < ep) {
register int caplen, hdrlen;
/*
* 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 (p->break_loop) {
if (n == 0) {
p->break_loop = 0;
return (-2);
} else {
p->bp = bp;
p->cc = ep - bp;
return (n);
}
}
caplen = bhp->bh_caplen;
hdrlen = bhp->bh_hdrlen;
datap = bp + hdrlen;
/*
* Short-circuit evaluation: if using BPF filter
* in kernel, no need to do it now - we already know
* the packet passed the filter.
*
#ifdef PCAP_FDDIPAD
* Note: the filter code was generated assuming
* that p->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.
#endif
*/
if (p->md.use_bpf ||
bpf_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) {
struct pcap_pkthdr pkthdr;
pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec;
#ifdef _AIX
/*
* AIX's BPF returns seconds/nanoseconds time
* stamps, not seconds/microseconds time stamps.
*/
pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec/1000;
#else
pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec;
#endif
#ifdef PCAP_FDDIPAD
if (caplen > pad)
pkthdr.caplen = caplen - pad;
else
pkthdr.caplen = 0;
if (bhp->bh_datalen > pad)
pkthdr.len = bhp->bh_datalen - pad;
else
pkthdr.len = 0;
datap += pad;
#else
pkthdr.caplen = caplen;
pkthdr.len = bhp->bh_datalen;
#endif
(*callback)(user, &pkthdr, datap);
bp += BPF_WORDALIGN(caplen + hdrlen);
if (++n >= cnt && cnt > 0) {
p->bp = bp;
p->cc = ep - bp;
return (n);
}
} else {
/*
* Skip this packet.
*/
bp += BPF_WORDALIGN(caplen + hdrlen);
}
}
#undef bhp
p->cc = 0;
return (n);
}
static int
pcap_inject_bpf(pcap_t *p, const void *buf, size_t size)
{
int ret;
ret = write(p->fd, buf, size);
#ifdef __APPLE__
if (ret == -1 && errno == EAFNOSUPPORT) {
/*
* In Mac OS X, there's a bug wherein setting the
* BIOCSHDRCMPLT flag causes writes to fail; see,
* for example:
*
* http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/BIOCSHDRCMPLT-10.3.3.patch
*
* So, if, on OS X, we get EAFNOSUPPORT from the write, we
* assume it's due to that bug, and turn off that flag
* and try again. If we succeed, it either means that
* somebody applied the fix from that URL, or other patches
* for that bug from
*
* http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/
*
* and are running a Darwin kernel with those fixes, or
* that Apple fixed the problem in some OS X release.
*/
u_int spoof_eth_src = 0;
if (ioctl(p->fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) {
(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"send: can't turn off BIOCSHDRCMPLT: %s",
pcap_strerror(errno));
return (-1);
}
/*
* Now try the write again.
*/
ret = write(p->fd, buf, size);
}
#endif /* __APPLE__ */
if (ret == -1) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
pcap_strerror(errno));
return (-1);
}
return (ret);
}
#ifdef _AIX
static int
bpf_odminit(char *errbuf)
{
char *errstr;
if (odm_initialize() == -1) {
if (odm_err_msg(odmerrno, &errstr) == -1)
errstr = "Unknown error";
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: odm_initialize failed: %s",
errstr);
return (-1);
}
if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) {
if (odm_err_msg(odmerrno, &errstr) == -1)
errstr = "Unknown error";
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s",
errstr);
return (-1);
}
return (0);
}
static int
bpf_odmcleanup(char *errbuf)
{
char *errstr;
if (odm_unlock(odmlockid) == -1) {
if (odm_err_msg(odmerrno, &errstr) == -1)
errstr = "Unknown error";
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: odm_unlock failed: %s",
errstr);
return (-1);
}
if (odm_terminate() == -1) {
if (odm_err_msg(odmerrno, &errstr) == -1)
errstr = "Unknown error";
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: odm_terminate failed: %s",
errstr);
return (-1);
}
return (0);
}
static int
bpf_load(char *errbuf)
{
long major;
int *minors;
int numminors, i, rc;
char buf[1024];
struct stat sbuf;
struct bpf_config cfg_bpf;
struct cfg_load cfg_ld;
struct cfg_kmod cfg_km;
/*
* This is very very close to what happens in the real implementation
* but I've fixed some (unlikely) bug situations.
*/
if (bpfloadedflag)
return (0);
if (bpf_odminit(errbuf) != 0)
return (-1);
major = genmajor(BPF_NAME);
if (major == -1) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: genmajor failed: %s", pcap_strerror(errno));
return (-1);
}
minors = getminor(major, &numminors, BPF_NAME);
if (!minors) {
minors = genminor("bpf", major, 0, BPF_MINORS, 1, 1);
if (!minors) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: genminor failed: %s",
pcap_strerror(errno));
return (-1);
}
}
if (bpf_odmcleanup(errbuf))
return (-1);
rc = stat(BPF_NODE "0", &sbuf);
if (rc == -1 && errno != ENOENT) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: can't stat %s: %s",
BPF_NODE "0", pcap_strerror(errno));
return (-1);
}
if (rc == -1 || getmajor(sbuf.st_rdev) != major) {
for (i = 0; i < BPF_MINORS; i++) {
sprintf(buf, "%s%d", BPF_NODE, i);
unlink(buf);
if (mknod(buf, S_IRUSR | S_IFCHR, domakedev(major, i)) == -1) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: can't mknod %s: %s",
buf, pcap_strerror(errno));
return (-1);
}
}
}
/* Check if the driver is loaded */
memset(&cfg_ld, 0x0, sizeof(cfg_ld));
cfg_ld.path = buf;
sprintf(cfg_ld.path, "%s/%s", DRIVER_PATH, BPF_NAME);
if ((sysconfig(SYS_QUERYLOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) ||
(cfg_ld.kmid == 0)) {
/* Driver isn't loaded, load it now */
if (sysconfig(SYS_SINGLELOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: could not load driver: %s",
strerror(errno));
return (-1);
}
}
/* Configure the driver */
cfg_km.cmd = CFG_INIT;
cfg_km.kmid = cfg_ld.kmid;
cfg_km.mdilen = sizeof(cfg_bpf);
cfg_km.mdiptr = (void *)&cfg_bpf;
for (i = 0; i < BPF_MINORS; i++) {
cfg_bpf.devno = domakedev(major, i);
if (sysconfig(SYS_CFGKMOD, (void *)&cfg_km, sizeof(cfg_km)) == -1) {
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"bpf_load: could not configure driver: %s",
strerror(errno));
return (-1);
}
}
bpfloadedflag = 1;
return (0);
}
#endif
/*
* Turn off rfmon mode if necessary.
*/
static void
pcap_close_bpf(pcap_t *p)
{
#ifdef HAVE_BSD_IEEE80211
int sock;
struct ifmediareq req;
struct ifreq ifr;
#endif
if (p->md.must_clear != 0) {
/*
* There's something we have to do when closing this
* pcap_t.
*/
#ifdef HAVE_BSD_IEEE80211
if (p->md.must_clear & MUST_CLEAR_RFMON) {
/*
* We put the interface into rfmon mode;
* take it out of rfmon mode.
*
* XXX - if somebody else wants it in rfmon
* mode, this code cannot know that, so it'll take
* it out of rfmon mode.
*/
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock == -1) {
fprintf(stderr,
"Can't restore interface flags (socket() failed: %s).\n"
"Please adjust manually.\n",
strerror(errno));
} else {
memset(&req, 0, sizeof(req));
strncpy(req.ifm_name, p->md.device,
sizeof(req.ifm_name));
if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
fprintf(stderr,
"Can't restore interface flags (SIOCGIFMEDIA failed: %s).\n"
"Please adjust manually.\n",
strerror(errno));
} else {
if (req.ifm_current & IFM_IEEE80211_MONITOR) {
/*
* Rfmon mode is currently on;
* turn it off.
*/
memset(&ifr, 0, sizeof(ifr));
(void)strncpy(ifr.ifr_name,
p->md.device,
sizeof(ifr.ifr_name));
ifr.ifr_media =
req.ifm_current & ~IFM_IEEE80211_MONITOR;
if (ioctl(sock, SIOCSIFMEDIA,
&ifr) == -1) {
fprintf(stderr,
"Can't restore interface flags (SIOCSIFMEDIA failed: %s).\n"
"Please adjust manually.\n",
strerror(errno));
}
}
}
close(sock);
}
}
#endif /* HAVE_BSD_IEEE80211 */
/*
* Take this pcap out of the list of pcaps for which we
* have to take the interface out of some mode.
*/
pcap_remove_from_pcaps_to_close(p);
}
if (p->md.device != NULL)
free(p->md.device);
p->md.device = NULL;
pcap_close_common(p);
}
static int
check_setif_failure(pcap_t *p, int error)
{
#ifdef __APPLE__
int fd;
struct ifreq ifr;
int err;
#endif
if (error == ENXIO) {
/*
* No such device exists.
*/
#ifdef __APPLE__
if (p->opt.rfmon && strncmp(p->opt.source, "wlt", 3) == 0) {
/*
* Monitor mode was requested, and we're trying
* to open a "wltN" device. Assume that this
* is 10.4 and that we were asked to open an
* "enN" device; if that device exists, return
* "monitor mode not supported on the device".
*/
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd != -1) {
strlcpy(ifr.ifr_name, "en",
sizeof(ifr.ifr_name));
strlcat(ifr.ifr_name, p->opt.source + 3,
sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
/*
* We assume this failed because
* the underlying device doesn't
* exist.
*/
err = PCAP_ERROR_NO_SUCH_DEVICE;
} else {
/*
* The underlying "enN" device
* exists, but there's no
* corresponding "wltN" device;
* that means that the "enN"
* device doesn't support
* monitor mode, probably because
* it's an Ethernet device rather
* than a wireless device.
*/
err = PCAP_ERROR_RFMON_NOTSUP;
}
close(fd);
} else {
/*
* We can't find out whether there's
* an underlying "enN" device, so
* just report "no such device".
*/
err = PCAP_ERROR_NO_SUCH_DEVICE;
}
return (err);
}
#endif
/*
* No such device.
*/
return (PCAP_ERROR_NO_SUCH_DEVICE);
} else {
/*
* Some other error; fill in the error string, and
* return PCAP_ERROR.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s",
p->opt.source, pcap_strerror(errno));
return (PCAP_ERROR);
}
}
static int
pcap_activate_bpf(pcap_t *p)
{
int err;
int fd;
struct ifreq ifr;
struct bpf_version bv;
#ifdef __APPLE__
char *wltdev = NULL;
#endif
#ifdef BIOCGDLTLIST
struct bpf_dltlist bdl;
#if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)
int new_dlt;
#endif
#endif /* BIOCGDLTLIST */
#if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)
u_int spoof_eth_src = 1;
#endif
u_int v;
struct bpf_insn total_insn;
struct bpf_program total_prog;
struct utsname osinfo;
int have_osinfo = 0;
fd = bpf_open(p);
if (fd < 0) {
err = PCAP_ERROR;
goto bad;
}
p->fd = fd;
if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
if (bv.bv_major != BPF_MAJOR_VERSION ||
bv.bv_minor < BPF_MINOR_VERSION) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"kernel bpf filter out of date");
err = PCAP_ERROR;
goto bad;
}
p->md.device = strdup(p->opt.source);
if (p->md.device == NULL) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
pcap_strerror(errno));
return PCAP_ERROR;
}
/*
* Attempt to find out the version of the OS on which we're running.
*/
if (uname(&osinfo) == 0)
have_osinfo = 1;
#ifdef __APPLE__
/*
* See comment in pcap_can_set_rfmon_bpf() for an explanation
* of why we check the version number.
*/
if (p->opt.rfmon) {
if (have_osinfo) {
/*
* We assume osinfo.sysname is "Darwin", because
* __APPLE__ is defined. We just check the version.
*/
if (osinfo.release[0] < '8' &&
osinfo.release[1] == '.') {
/*
* 10.3 (Darwin 7.x) or earlier.
*/
err = PCAP_ERROR_RFMON_NOTSUP;
goto bad;
}
if (osinfo.release[0] == '8' &&
osinfo.release[1] == '.') {
/*
* 10.4 (Darwin 8.x). s/en/wlt/
*/
if (strncmp(p->opt.source, "en", 2) != 0) {
/*
* Not an enN device; no monitor
* mode.
*/
err = PCAP_ERROR_RFMON_NOTSUP;
goto bad;
}
wltdev = malloc(strlen(p->opt.source) + 2);
if (wltdev == NULL) {
(void)snprintf(p->errbuf,
PCAP_ERRBUF_SIZE, "malloc: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
strcpy(wltdev, "wlt");
strcat(wltdev, p->opt.source + 2);
free(p->opt.source);
p->opt.source = wltdev;
}
/*
* Everything else is 10.5 or later; for those,
* we just open the enN device, and set the DLT.
*/
}
}
#endif /* __APPLE__ */
/*
* Set the buffer size.
*/
if (p->opt.buffer_size != 0) {
/*
* A buffer size was explicitly specified; use it.
*/
if (ioctl(fd, BIOCSBLEN, (caddr_t)&p->opt.buffer_size) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSBLEN: %s: %s", p->opt.source,
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
/*
* Now bind to the device.
*/
(void)strncpy(ifr.ifr_name, p->opt.source,
sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
err = check_setif_failure(p, errno);
goto bad;
}
} else {
/*
* No buffer size was explicitly specified.
*
* Try finding a good size for the buffer; 32768 may
* be too big, so keep cutting it in half until we
* find a size that works, or run out of sizes to try.
* If the default is larger, don't make it smaller.
*/
if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || v < 32768)
v = 32768;
for ( ; v != 0; v >>= 1) {
/*
* Ignore the return value - this is because the
* call fails on BPF systems that don't have
* kernel malloc. And if the call fails, it's
* no big deal, we just continue to use the
* standard buffer size.
*/
(void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);
(void)strncpy(ifr.ifr_name, p->opt.source,
sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0)
break; /* that size worked; we're done */
if (errno != ENOBUFS) {
err = check_setif_failure(p, errno);
goto bad;
}
}
if (v == 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSBLEN: %s: No buffer size worked",
p->opt.source);
err = PCAP_ERROR;
goto bad;
}
}
/* Get the data link layer type. */
if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
#ifdef _AIX
/*
* AIX's BPF returns IFF_ types, not DLT_ types, in BIOCGDLT.
*/
switch (v) {
case IFT_ETHER:
case IFT_ISO88023:
v = DLT_EN10MB;
break;
case IFT_FDDI:
v = DLT_FDDI;
break;
case IFT_ISO88025:
v = DLT_IEEE802;
break;
case IFT_LOOP:
v = DLT_NULL;
break;
default:
/*
* We don't know what to map this to yet.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown interface type %u",
v);
err = PCAP_ERROR;
goto bad;
}
#endif
#if _BSDI_VERSION - 0 >= 199510
/* The SLIP and PPP link layer header changed in BSD/OS 2.1 */
switch (v) {
case DLT_SLIP:
v = DLT_SLIP_BSDOS;
break;
case DLT_PPP:
v = DLT_PPP_BSDOS;
break;
case 11: /*DLT_FR*/
v = DLT_FRELAY;
break;
case 12: /*DLT_C_HDLC*/
v = DLT_CHDLC;
break;
}
#endif
#ifdef BIOCGDLTLIST
/*
* We know the default link type -- now determine all the DLTs
* this interface supports. If this fails with EINVAL, it's
* not fatal; we just don't get to use the feature later.
*/
if (get_dlt_list(fd, v, &bdl, p->errbuf) == -1) {
err = PCAP_ERROR;
goto bad;
}
p->dlt_count = bdl.bfl_len;
p->dlt_list = bdl.bfl_list;
#ifdef __APPLE__
/*
* Monitor mode fun, continued.
*
* For 10.5 and, we're assuming, later releases, as noted above,
* 802.1 adapters that support monitor mode offer both DLT_EN10MB,
* DLT_IEEE802_11, and possibly some 802.11-plus-radio-information
* DLT_ value. Choosing one of the 802.11 DLT_ values will turn
* monitor mode on.
*
* Therefore, if the user asked for monitor mode, we filter out
* the DLT_EN10MB value, as you can't get that in monitor mode,
* and, if the user didn't ask for monitor mode, we filter out
* the 802.11 DLT_ values, because selecting those will turn
* monitor mode on. Then, for monitor mode, if an 802.11-plus-
* radio DLT_ value is offered, we try to select that, otherwise
* we try to select DLT_IEEE802_11.
*/
if (have_osinfo) {
if (isdigit((unsigned)osinfo.release[0]) &&
(osinfo.release[0] == '9' ||
isdigit((unsigned)osinfo.release[1]))) {
/*
* 10.5 (Darwin 9.x), or later.
*/
new_dlt = find_802_11(&bdl);
if (new_dlt != -1) {
/*
* We have at least one 802.11 DLT_ value,
* so this is an 802.11 interface.
* new_dlt is the best of the 802.11
* DLT_ values in the list.
*/
if (p->opt.rfmon) {
/*
* Our caller wants monitor mode.
* Purge DLT_EN10MB from the list
* of link-layer types, as selecting
* it will keep monitor mode off.
*/
remove_en(p);
/*
* If the new mode we want isn't
* the default mode, attempt to
* select the new mode.
*/
if (new_dlt != v) {
if (ioctl(p->fd, BIOCSDLT,
&new_dlt) != -1) {
/*
* We succeeded;
* make this the
* new DLT_ value.
*/
v = new_dlt;
}
}
} else {
/*
* Our caller doesn't want
* monitor mode. Unless this
* is being done by pcap_open_live(),
* purge the 802.11 link-layer types
* from the list, as selecting
* one of them will turn monitor
* mode on.
*/
if (!p->oldstyle)
remove_802_11(p);
}
} else {
if (p->opt.rfmon) {
/*
* The caller requested monitor
* mode, but we have no 802.11
* link-layer types, so they
* can't have it.
*/
err = PCAP_ERROR_RFMON_NOTSUP;
goto bad;
}
}
}
}
#elif defined(HAVE_BSD_IEEE80211)
/*
* *BSD with the new 802.11 ioctls.
* Do we want monitor mode?
*/
if (p->opt.rfmon) {
/*
* Try to put the interface into monitor mode.
*/
err = monitor_mode(p, 1);
if (err != 0) {
/*
* We failed.
*/
goto bad;
}
/*
* We're in monitor mode.
* Try to find the best 802.11 DLT_ value and, if we
* succeed, try to switch to that mode if we're not
* already in that mode.
*/
new_dlt = find_802_11(&bdl);
if (new_dlt != -1) {
/*
* We have at least one 802.11 DLT_ value.
* new_dlt is the best of the 802.11
* DLT_ values in the list.
*
* If the new mode we want isn't the default mode,
* attempt to select the new mode.
*/
if (new_dlt != v) {
if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) {
/*
* We succeeded; make this the
* new DLT_ value.
*/
v = new_dlt;
}
}
}
}
#endif /* various platforms */
#endif /* BIOCGDLTLIST */
/*
* If this is an Ethernet device, and we don't have a DLT_ list,
* give it a list with DLT_EN10MB and DLT_DOCSIS. (That'd give
* 802.11 interfaces DLT_DOCSIS, which isn't the right thing to
* do, but there's not much we can do about that without finding
* some other way of determining whether it's an Ethernet or 802.11
* device.)
*/
if (v == DLT_EN10MB && p->dlt_count == 0) {
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;
}
}
#ifdef PCAP_FDDIPAD
if (v == DLT_FDDI)
p->fddipad = PCAP_FDDIPAD;
else
p->fddipad = 0;
#endif
p->linktype = v;
#if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)
/*
* Do a BIOCSHDRCMPLT, if defined, to turn that flag on, so
* the link-layer source address isn't forcibly overwritten.
* (Should we ignore errors? Should we do this only if
* we're open for writing?)
*
* XXX - I seem to remember some packet-sending bug in some
* BSDs - check CVS log for "bpf.c"?
*/
if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) {
(void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"BIOCSHDRCMPLT: %s", pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
#endif
/* set timeout */
if (p->md.timeout != 0) {
/*
* XXX - is this seconds/nanoseconds in AIX?
* (Treating it as such doesn't fix the timeout
* problem described below.)
*/
struct timeval to;
to.tv_sec = p->md.timeout / 1000;
to.tv_usec = (p->md.timeout * 1000) % 1000000;
if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
}
#ifdef _AIX
#ifdef BIOCIMMEDIATE
/*
* Darren Reed notes that
*
* On AIX (4.2 at least), if BIOCIMMEDIATE is not set, the
* timeout appears to be ignored and it waits until the buffer
* is filled before returning. The result of not having it
* set is almost worse than useless if your BPF filter
* is reducing things to only a few packets (i.e. one every
* second or so).
*
* so we turn BIOCIMMEDIATE mode on if this is AIX.
*
* We don't turn it on for other platforms, as that means we
* get woken up for every packet, which may not be what we want;
* in the Winter 1993 USENIX paper on BPF, they say:
*
* Since a process might want to look at every packet on a
* network and the time between packets can be only a few
* microseconds, it is not possible to do a read system call
* per packet and BPF must collect the data from several
* packets and return it as a unit when the monitoring
* application does a read.
*
* which I infer is the reason for the timeout - it means we
* wait that amount of time, in the hopes that more packets
* will arrive and we'll get them all with one read.
*
* Setting BIOCIMMEDIATE mode on FreeBSD (and probably other
* BSDs) causes the timeout to be ignored.
*
* On the other hand, some platforms (e.g., Linux) don't support
* timeouts, they just hand stuff to you as soon as it arrives;
* if that doesn't cause a problem on those platforms, it may
* be OK to have BIOCIMMEDIATE mode on BSD as well.
*
* (Note, though, that applications may depend on the read
* completing, even if no packets have arrived, when the timeout
* expires, e.g. GUI applications that have to check for input
* while waiting for packets to arrive; a non-zero timeout
* prevents "select()" from working right on FreeBSD and
* possibly other BSDs, as the timer doesn't start until a
* "read()" is done, so the timer isn't in effect if the
* application is blocked on a "select()", and the "select()"
* doesn't get woken up for a BPF device until the buffer
* fills up.)
*/
v = 1;
if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
#endif /* BIOCIMMEDIATE */
#endif /* _AIX */
if (p->opt.promisc) {
/* set promiscuous mode, okay if it fails */
if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s",
pcap_strerror(errno));
}
}
if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
p->bufsize = v;
p->buffer = (u_char *)malloc(p->bufsize);
if (p->buffer == NULL) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
#ifdef _AIX
/* For some strange reason this seems to prevent the EFAULT
* problems we have experienced from AIX BPF. */
memset(p->buffer, 0x0, p->bufsize);
#endif
/*
* If there's no filter program installed, there's
* no indication to the kernel of what the snapshot
* length should be, so no snapshotting is done.
*
* Therefore, when we open the device, we install
* an "accept everything" filter with the specified
* snapshot length.
*/
total_insn.code = (u_short)(BPF_RET | BPF_K);
total_insn.jt = 0;
total_insn.jf = 0;
total_insn.k = p->snapshot;
total_prog.bf_len = 1;
total_prog.bf_insns = &total_insn;
if (ioctl(p->fd, BIOCSETF, (caddr_t)&total_prog) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
pcap_strerror(errno));
err = PCAP_ERROR;
goto bad;
}
/*
* On most BPF platforms, either you can do a "select()" or
* "poll()" on a BPF file descriptor and it works correctly,
* or you can do it and it will return "readable" if the
* hold buffer is full but not if the timeout expires *and*
* a non-blocking read will, if the hold buffer is empty
* but the store buffer isn't empty, rotate the buffers
* and return what packets are available.
*
* In the latter case, the fact that a non-blocking read
* will give you the available packets means you can work
* around the failure of "select()" and "poll()" to wake up
* and return "readable" when the timeout expires by using
* the timeout as the "select()" or "poll()" timeout, putting
* the BPF descriptor into non-blocking mode, and read from
* it regardless of whether "select()" reports it as readable
* or not.
*
* However, in FreeBSD 4.3 and 4.4, "select()" and "poll()"
* won't wake up and return "readable" if the timer expires
* and non-blocking reads return EWOULDBLOCK if the hold
* buffer is empty, even if the store buffer is non-empty.
*
* This means the workaround in question won't work.
*
* Therefore, on FreeBSD 4.3 and 4.4, we set "p->selectable_fd"
* to -1, which means "sorry, you can't use 'select()' or 'poll()'
* here". On all other BPF platforms, we set it to the FD for
* the BPF device; in NetBSD, OpenBSD, and Darwin, a non-blocking
* read will, if the hold buffer is empty and the store buffer
* isn't empty, rotate the buffers and return what packets are
* there (and in sufficiently recent versions of OpenBSD
* "select()" and "poll()" should work correctly).
*
* XXX - what about AIX?
*/
p->selectable_fd = p->fd; /* assume select() works until we know otherwise */
if (have_osinfo) {
/*
* We can check what OS this is.
*/
if (strcmp(osinfo.sysname, "FreeBSD") == 0) {
if (strncmp(osinfo.release, "4.3-", 4) == 0 ||
strncmp(osinfo.release, "4.4-", 4) == 0)
p->selectable_fd = -1;
}
}
p->read_op = pcap_read_bpf;
p->inject_op = pcap_inject_bpf;
p->setfilter_op = pcap_setfilter_bpf;
p->setdirection_op = pcap_setdirection_bpf;
p->set_datalink_op = pcap_set_datalink_bpf;
p->getnonblock_op = pcap_getnonblock_fd;
p->setnonblock_op = pcap_setnonblock_fd;
p->stats_op = pcap_stats_bpf;
p->close_op = pcap_close_bpf;
return (0);
bad:
(void)close(fd);
if (p->buffer != NULL) {
free(p->buffer);
p->buffer = NULL;
}
return (err);
}
int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
#ifdef HAVE_DAG_API
if (dag_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif /* HAVE_DAG_API */
return (0);
}
#ifdef HAVE_BSD_IEEE80211
static int
monitor_mode(pcap_t *p, int set)
{
int sock;
struct ifmediareq req;
int *media_list;
int i;
int can_do;
struct ifreq ifr;
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock == -1) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "can't open socket: %s",
pcap_strerror(errno));
return (PCAP_ERROR);
}
memset(&req, 0, sizeof req);
strncpy(req.ifm_name, p->opt.source, sizeof req.ifm_name);
/*
* Find out how many media types we have.
*/
if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
/*
* Can't get the media types.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA: %s",
pcap_strerror(errno));
close(sock);
return (PCAP_ERROR);
}
if (req.ifm_count == 0) {
/*
* No media types.
*/
close(sock);
return (PCAP_ERROR_RFMON_NOTSUP);
}
/*
* Allocate a buffer to hold all the media types, and
* get the media types.
*/
media_list = malloc(req.ifm_count * sizeof(int));
if (media_list == NULL) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s",
pcap_strerror(errno));
close(sock);
return (PCAP_ERROR);
}
req.ifm_ulist = media_list;
if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA: %s",
pcap_strerror(errno));
free(media_list);
close(sock);
return (PCAP_ERROR);
}
/*
* Look for an 802.11 "automatic" media type.
* We assume that all 802.11 adapters have that media type,
* and that it will carry the monitor mode supported flag.
*/
can_do = 0;
for (i = 0; i < req.ifm_count; i++) {
if (IFM_TYPE(media_list[i]) == IFM_IEEE80211
&& IFM_SUBTYPE(media_list[i]) == IFM_AUTO) {
/* OK, does it do monitor mode? */
if (media_list[i] & IFM_IEEE80211_MONITOR) {
can_do = 1;
break;
}
}
}
free(media_list);
if (!can_do) {
/*
* This adapter doesn't support monitor mode.
*/
close(sock);
return (PCAP_ERROR_RFMON_NOTSUP);
}
if (set) {
/*
* Don't just check whether we can enable monitor mode,
* do so, if it's not already enabled.
*/
if ((req.ifm_current & IFM_IEEE80211_MONITOR) == 0) {
/*
* Monitor mode isn't currently on, so turn it on,
* and remember that we should turn it off when the
* pcap_t is closed.
*/
/*
* If we haven't already done so, arrange to have
* "pcap_close_all()" called when we exit.
*/
if (!pcap_do_addexit(p)) {
/*
* "atexit()" failed; don't put the interface
* in monitor mode, just give up.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"atexit failed");
close(sock);
return (PCAP_ERROR);
}
memset(&ifr, 0, sizeof(ifr));
(void)strncpy(ifr.ifr_name, p->opt.source,
sizeof(ifr.ifr_name));
ifr.ifr_media = req.ifm_current | IFM_IEEE80211_MONITOR;
if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"SIOCSIFMEDIA: %s", pcap_strerror(errno));
close(sock);
return (PCAP_ERROR);
}
p->md.must_clear |= MUST_CLEAR_RFMON;
/*
* Add this to the list of pcaps to close when we exit.
*/
pcap_add_to_pcaps_to_close(p);
}
}
return (0);
}
#endif /* HAVE_BSD_IEEE80211 */
#if defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211))
/*
* Check whether we have any 802.11 link-layer types; return the best
* of the 802.11 link-layer types if we find one, and return -1
* otherwise.
*
* DLT_IEEE802_11_RADIO, with the radiotap header, is considered the
* best 802.11 link-layer type; any of the other 802.11-plus-radio
* headers are second-best; 802.11 with no radio information is
* the least good.
*/
static int
find_802_11(struct bpf_dltlist *bdlp)
{
int new_dlt;
int i;
/*
* Scan the list of DLT_ values, looking for 802.11 values,
* and, if we find any, choose the best of them.
*/
new_dlt = -1;
for (i = 0; i < bdlp->bfl_len; i++) {
switch (bdlp->bfl_list[i]) {
case DLT_IEEE802_11:
/*
* 802.11, but no radio.
*
* Offer this, and select it as the new mode
* unless we've already found an 802.11
* header with radio information.
*/
if (new_dlt == -1)
new_dlt = bdlp->bfl_list[i];
break;
case DLT_PRISM_HEADER:
case DLT_AIRONET_HEADER:
case DLT_IEEE802_11_RADIO_AVS:
/*
* 802.11 with radio, but not radiotap.
*
* Offer this, and select it as the new mode
* unless we've already found the radiotap DLT_.
*/
if (new_dlt != DLT_IEEE802_11_RADIO)
new_dlt = bdlp->bfl_list[i];
break;
case DLT_IEEE802_11_RADIO:
/*
* 802.11 with radiotap.
*
* Offer this, and select it as the new mode.
*/
new_dlt = bdlp->bfl_list[i];
break;
default:
/*
* Not 802.11.
*/
break;
}
}
return (new_dlt);
}
#endif /* defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) */
#if defined(__APPLE__) && defined(BIOCGDLTLIST)
/*
* Remove DLT_EN10MB from the list of DLT_ values.
*/
static void
remove_en(pcap_t *p)
{
int i, j;
/*
* Scan the list of DLT_ values and discard DLT_EN10MB.
*/
j = 0;
for (i = 0; i < p->dlt_count; i++) {
switch (p->dlt_list[i]) {
case DLT_EN10MB:
/*
* Don't offer this one.
*/
continue;
default:
/*
* Just copy this mode over.
*/
break;
}
/*
* Copy this DLT_ value to its new position.
*/
p->dlt_list[j] = p->dlt_list[i];
j++;
}
/*
* Set the DLT_ count to the number of entries we copied.
*/
p->dlt_count = j;
}
/*
* Remove DLT_EN10MB from the list of DLT_ values, and look for the
* best 802.11 link-layer type in that list and return it.
* Radiotap is better than anything else; 802.11 with any other radio
* header is better than 802.11 with no radio header.
*/
static void
remove_802_11(pcap_t *p)
{
int i, j;
/*
* Scan the list of DLT_ values and discard 802.11 values.
*/
j = 0;
for (i = 0; i < p->dlt_count; i++) {
switch (p->dlt_list[i]) {
case DLT_IEEE802_11:
case DLT_PRISM_HEADER:
case DLT_AIRONET_HEADER:
case DLT_IEEE802_11_RADIO:
case DLT_IEEE802_11_RADIO_AVS:
/*
* 802.11. Don't offer this one.
*/
continue;
default:
/*
* Just copy this mode over.
*/
break;
}
/*
* Copy this DLT_ value to its new position.
*/
p->dlt_list[j] = p->dlt_list[i];
j++;
}
/*
* Set the DLT_ count to the number of entries we copied.
*/
p->dlt_count = j;
}
#endif /* defined(__APPLE__) && defined(BIOCGDLTLIST) */
static int
pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp)
{
/*
* Free any user-mode filter we might happen to have installed.
*/
pcap_freecode(&p->fcode);
/*
* Try to install the kernel filter.
*/
if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) == 0) {
/*
* It worked.
*/
p->md.use_bpf = 1; /* filtering in the kernel */
/*
* 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 failed.
*
* If it failed with EINVAL, that's probably because the program
* is invalid or too big. Validate it ourselves; if we like it
* (we currently allow backward branches, to support protochain),
* run it in userland. (There's no notion of "too big" for
* userland.)
*
* Otherwise, just give up.
* XXX - if the copy of the program into the kernel failed,
* we will get EINVAL rather than, say, EFAULT on at least
* some kernels.
*/
if (errno != EINVAL) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s",
pcap_strerror(errno));
return (-1);
}
/*
* install_bpf_program() validates the program.
*
* XXX - what if we already have a filter in the kernel?
*/
if (install_bpf_program(p, fp) < 0)
return (-1);
p->md.use_bpf = 0; /* filtering in userland */
return (0);
}
/*
* Set direction flag: Which packets do we accept on a forwarding
* single device? IN, OUT or both?
*/
static int
pcap_setdirection_bpf(pcap_t *p, pcap_direction_t d)
{
#if defined(BIOCSDIRECTION)
u_int direction;
direction = (d == PCAP_D_IN) ? BPF_D_IN :
((d == PCAP_D_OUT) ? BPF_D_OUT : BPF_D_INOUT);
if (ioctl(p->fd, BIOCSDIRECTION, &direction) == -1) {
(void) snprintf(p->errbuf, sizeof(p->errbuf),
"Cannot set direction to %s: %s",
(d == PCAP_D_IN) ? "PCAP_D_IN" :
((d == PCAP_D_OUT) ? "PCAP_D_OUT" : "PCAP_D_INOUT"),
strerror(errno));
return (-1);
}
return (0);
#elif defined(BIOCSSEESENT)
u_int seesent;
/*
* We don't support PCAP_D_OUT.
*/
if (d == PCAP_D_OUT) {
snprintf(p->errbuf, sizeof(p->errbuf),
"Setting direction to PCAP_D_OUT is not supported on BPF");
return -1;
}
seesent = (d == PCAP_D_INOUT);
if (ioctl(p->fd, BIOCSSEESENT, &seesent) == -1) {
(void) snprintf(p->errbuf, sizeof(p->errbuf),
"Cannot set direction to %s: %s",
(d == PCAP_D_INOUT) ? "PCAP_D_INOUT" : "PCAP_D_IN",
strerror(errno));
return (-1);
}
return (0);
#else
(void) snprintf(p->errbuf, sizeof(p->errbuf),
"This system doesn't support BIOCSSEESENT, so the direction can't be set");
return (-1);
#endif
}
static int
pcap_set_datalink_bpf(pcap_t *p, int dlt)
{
#ifdef BIOCSDLT
if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) {
(void) snprintf(p->errbuf, sizeof(p->errbuf),
"Cannot set DLT %d: %s", dlt, strerror(errno));
return (-1);
}
#endif
return (0);
}
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