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dumpcap.c
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/* dumpcap.c
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h> /* for exit() */
#include <glib.h>
#include <string.h>
#include <ctype.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if defined(__APPLE__) && defined(__LP64__)
#include <sys/utsname.h>
#endif
#include <signal.h>
#include <errno.h>
#ifdef HAVE_LIBZ
#include <zlib.h> /* to get the libz version number */
#endif
#include <wsutil/cmdarg_err.h>
#include <wsutil/crash_info.h>
#include <wsutil/copyright_info.h>
#include <wsutil/ws_version_info.h>
#ifndef HAVE_GETOPT
#include "wsutil/wsgetopt.h"
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_LIBCAP
# include <sys/prctl.h>
# include <sys/capability.h>
#endif
#include "ringbuffer.h"
#include "version_info.h"
#include "caputils/capture_ifinfo.h"
#include "caputils/capture-pcap-util.h"
#include "caputils/capture-pcap-util-int.h"
#ifdef _WIN32
#include "caputils/capture-wpcap.h"
#endif /* _WIN32 */
#include "pcapio.h"
#ifdef _WIN32
#include "caputils/capture-wpcap.h"
#include <wsutil/unicode-utils.h>
#endif
#ifndef _WIN32
#include <sys/un.h>
#endif
#ifdef NEED_INET_V6DEFS_H
# include "wsutil/inet_v6defs.h"
#endif
#include <wsutil/clopts_common.h>
#include <wsutil/privileges.h>
#include "sync_pipe.h"
#include "capture_opts.h"
#include <capchild/capture_session.h>
#include <capchild/capture_sync.h>
#include "conditions.h"
#include "capture_stop_conditions.h"
#include "wsutil/tempfile.h"
#include "log.h"
#include "wsutil/file_util.h"
#include "wsutil/os_version_info.h"
#include "caputils/ws80211_utils.h"
/*
* Get information about libpcap format from "wiretap/libpcap.h".
* XXX - can we just use pcap_open_offline() to read the pipe?
*/
#include "wiretap/libpcap.h"
/**#define DEBUG_DUMPCAP**/
/**#define DEBUG_CHILD_DUMPCAP**/
#ifdef _WIN32
#ifdef DEBUG_DUMPCAP
#include <conio.h> /* _getch() */
#endif
#endif
#ifdef DEBUG_CHILD_DUMPCAP
FILE *debug_log; /* for logging debug messages to */
/* a file if DEBUG_CHILD_DUMPCAP */
/* is defined */
#endif
static GAsyncQueue *pcap_queue;
static gint64 pcap_queue_bytes;
static gint64 pcap_queue_packets;
static gint64 pcap_queue_byte_limit = 0;
static gint64 pcap_queue_packet_limit = 0;
static gboolean capture_child = FALSE; /* FALSE: standalone call, TRUE: this is an Wireshark capture child */
#ifdef _WIN32
static gchar *sig_pipe_name = NULL;
static HANDLE sig_pipe_handle = NULL;
static gboolean signal_pipe_check_running(void);
#endif
#ifdef SIGINFO
static gboolean infodelay; /* if TRUE, don't print capture info in SIGINFO handler */
static gboolean infoprint; /* if TRUE, print capture info after clearing infodelay */
#endif /* SIGINFO */
/** Stop a low-level capture (stops the capture child). */
static void capture_loop_stop(void);
/** Close a pipe, or socket if \a from_socket is TRUE */
static void cap_pipe_close(int pipe_fd, gboolean from_socket _U_);
#ifdef __linux__
/*
* Enable kernel BPF JIT compiler if available.
* If any calls fail, just drive on - the JIT compiler might not be
* enabled, but filtering will still work, and it's not clear what
* we could do if the calls fail; should we just report the error
* and not continue to capture, should we report it as a warning, or
* what?
*/
static void
enable_kernel_bpf_jit_compiler(void)
{
int fd;
ssize_t written _U_;
static const char file[] = "/proc/sys/net/core/bpf_jit_enable";
fd = ws_open(file, O_WRONLY);
if (fd < 0)
return;
written = write(fd, "1", strlen("1"));
close(fd);
}
#endif
#if !defined (__linux__)
#ifndef HAVE_PCAP_BREAKLOOP
/*
* We don't have pcap_breakloop(), which is the only way to ensure that
* pcap_dispatch(), pcap_loop(), or even pcap_next() or pcap_next_ex()
* won't, if the call to read the next packet or batch of packets is
* is interrupted by a signal on UN*X, just go back and try again to
* read again.
*
* On UN*X, we catch SIGINT as a "stop capturing" signal, and, in
* the signal handler, set a flag to stop capturing; however, without
* a guarantee of that sort, we can't guarantee that we'll stop capturing
* if the read will be retried and won't time out if no packets arrive.
*
* Therefore, on at least some platforms, we work around the lack of
* pcap_breakloop() by doing a select() on the pcap_t's file descriptor
* to wait for packets to arrive, so that we're probably going to be
* blocked in the select() when the signal arrives, and can just bail
* out of the loop at that point.
*
* However, we don't want to do that on BSD (because "select()" doesn't work
* correctly on BPF devices on at least some releases of some flavors of
* BSD), and we don't want to do it on Windows (because "select()" is
* something for sockets, not for arbitrary handles). (Note that "Windows"
* here includes Cygwin; even in its pretend-it's-UNIX environment, we're
* using WinPcap, not a UNIX libpcap.)
*
* Fortunately, we don't need to do it on BSD, because the libpcap timeout
* on BSD times out even if no packets have arrived, so we'll eventually
* exit pcap_dispatch() with an indication that no packets have arrived,
* and will break out of the capture loop at that point.
*
* On Windows, we can't send a SIGINT to stop capturing, so none of this
* applies in any case.
*
* XXX - the various BSDs appear to define BSD in <sys/param.h>; we don't
* want to include it if it's not present on this platform, however.
*/
# if !defined(__FreeBSD__) && !defined(__NetBSD__) && !defined(__OpenBSD__) && \
!defined(__bsdi__) && !defined(__APPLE__) && !defined(_WIN32) && \
!defined(__CYGWIN__)
# define MUST_DO_SELECT
# endif /* avoid select */
#endif /* HAVE_PCAP_BREAKLOOP */
#else /* linux */
/* whatever the deal with pcap_breakloop, linux doesn't support timeouts
* in pcap_dispatch(); on the other hand, select() works just fine there.
* Hence we use a select for that come what may.
*
* XXX - with TPACKET_V1 and TPACKET_V2, it currently uses select()
* internally, and, with TPACKET_V3, once that's supported, it'll
* support timeouts, at least as I understand the way the code works.
*/
#define MUST_DO_SELECT
#endif
/** init the capture filter */
typedef enum {
INITFILTER_NO_ERROR,
INITFILTER_BAD_FILTER,
INITFILTER_OTHER_ERROR
} initfilter_status_t;
typedef enum {
STATE_EXPECT_REC_HDR,
STATE_READ_REC_HDR,
STATE_EXPECT_DATA,
STATE_READ_DATA
} cap_pipe_state_t;
typedef enum {
PIPOK,
PIPEOF,
PIPERR,
PIPNEXIST
} cap_pipe_err_t;
typedef struct _pcap_options {
guint32 received;
guint32 dropped;
guint32 flushed;
pcap_t *pcap_h;
#ifdef MUST_DO_SELECT
int pcap_fd; /**< pcap file descriptor */
#endif
gboolean pcap_err;
guint interface_id;
GThread *tid;
int snaplen;
int linktype;
gboolean ts_nsec; /**< TRUE if we're using nanosecond precision. */
/**< capture pipe (unix only "input file") */
gboolean from_cap_pipe; /**< TRUE if we are capturing data from a capture pipe */
gboolean from_cap_socket; /**< TRUE if we're capturing from socket */
struct pcap_hdr cap_pipe_hdr; /**< Pcap header when capturing from a pipe */
struct pcaprec_modified_hdr cap_pipe_rechdr; /**< Pcap record header when capturing from a pipe */
#ifdef _WIN32
HANDLE cap_pipe_h; /**< The handle of the capture pipe */
#endif
int cap_pipe_fd; /**< the file descriptor of the capture pipe */
gboolean cap_pipe_modified; /**< TRUE if data in the pipe uses modified pcap headers */
gboolean cap_pipe_byte_swapped; /**< TRUE if data in the pipe is byte swapped */
#if defined(_WIN32)
char * cap_pipe_buf; /**< Pointer to the data buffer we read into */
DWORD cap_pipe_bytes_to_read; /**< Used by cap_pipe_dispatch */
DWORD cap_pipe_bytes_read; /**< Used by cap_pipe_dispatch */
#else
size_t cap_pipe_bytes_to_read; /**< Used by cap_pipe_dispatch */
size_t cap_pipe_bytes_read; /**< Used by cap_pipe_dispatch */
#endif
cap_pipe_state_t cap_pipe_state;
cap_pipe_err_t cap_pipe_err;
#if defined(_WIN32)
GMutex *cap_pipe_read_mtx;
GAsyncQueue *cap_pipe_pending_q, *cap_pipe_done_q;
#endif
} pcap_options;
typedef struct _loop_data {
/* common */
gboolean go; /**< TRUE as long as we're supposed to keep capturing */
int err; /**< if non-zero, error seen while capturing */
gint packet_count; /**< Number of packets we have already captured */
gint packet_max; /**< Number of packets we're supposed to capture - 0 means infinite */
guint inpkts_to_sync_pipe; /**< Packets not already send out to the sync_pipe */
#ifdef SIGINFO
gboolean report_packet_count; /**< Set by SIGINFO handler; print packet count */
#endif
GArray *pcaps;
/* output file(s) */
FILE *pdh;
int save_file_fd;
guint64 bytes_written;
guint32 autostop_files;
} loop_data;
typedef struct _pcap_queue_element {
pcap_options *pcap_opts;
struct pcap_pkthdr phdr;
u_char *pd;
} pcap_queue_element;
/*
* Standard secondary message for unexpected errors.
*/
static const char please_report[] =
"Please report this to the Wireshark developers.\n"
"http://bugs.wireshark.org/\n"
"(This is not a crash; please do not report it as such.)";
/*
* This needs to be static, so that the SIGINT handler can clear the "go"
* flag.
*/
static loop_data global_ld;
/*
* Timeout, in milliseconds, for reads from the stream of captured packets
* from a capture device.
*
* A bug in Mac OS X 10.6 and 10.6.1 causes calls to pcap_open_live(), in
* 64-bit applications, with sub-second timeouts not to work. The bug is
* fixed in 10.6.2, re-broken in 10.6.3, and again fixed in 10.6.5.
*/
#if defined(__APPLE__) && defined(__LP64__)
static gboolean need_timeout_workaround;
#define CAP_READ_TIMEOUT (need_timeout_workaround ? 1000 : 250)
#else
#define CAP_READ_TIMEOUT 250
#endif
/*
* Timeout, in microseconds, for reads from the stream of captured packets
* from a pipe. Pipes don't have the same problem that BPF devices do
* in OS X 10.6, 10.6.1, 10.6.3, and 10.6.4, so we always use a timeout
* of 250ms, i.e. the same value as CAP_READ_TIMEOUT when not on one
* of the offending versions of Snow Leopard.
*
* On Windows this value is converted to milliseconds and passed to
* WaitForSingleObject. If it's less than 1000 WaitForSingleObject
* will return immediately.
*/
#if defined(_WIN32)
#define PIPE_READ_TIMEOUT 100000
#else
#define PIPE_READ_TIMEOUT 250000
#endif
#define WRITER_THREAD_TIMEOUT 100000 /* usecs */
static void
console_log_handler(const char *log_domain, GLogLevelFlags log_level,
const char *message, gpointer user_data _U_);
/* capture related options */
static capture_options global_capture_opts;
static gboolean quiet = FALSE;
static gboolean use_threads = FALSE;
static guint64 start_time;
static void capture_loop_write_packet_cb(u_char *pcap_opts_p, const struct pcap_pkthdr *phdr,
const u_char *pd);
static void capture_loop_queue_packet_cb(u_char *pcap_opts_p, const struct pcap_pkthdr *phdr,
const u_char *pd);
static void capture_loop_get_errmsg(char *errmsg, int errmsglen, const char *fname,
int err, gboolean is_close);
static void WS_MSVC_NORETURN exit_main(int err) G_GNUC_NORETURN;
static void report_new_capture_file(const char *filename);
static void report_packet_count(unsigned int packet_count);
static void report_packet_drops(guint32 received, guint32 pcap_drops, guint32 drops, guint32 flushed, guint32 ps_ifdrop, gchar *name);
static void report_capture_error(const char *error_msg, const char *secondary_error_msg);
static void report_cfilter_error(capture_options *capture_opts, guint i, const char *errmsg);
#define MSG_MAX_LENGTH 4096
/* Copied from pcapio.c pcapng_write_interface_statistics_block()*/
static guint64
create_timestamp(void) {
guint64 timestamp;
#ifdef _WIN32
FILETIME now;
#else
struct timeval now;
#endif
#ifdef _WIN32
/*
* Current time, represented as 100-nanosecond intervals since
* January 1, 1601, 00:00:00 UTC.
*
* I think DWORD might be signed, so cast both parts of "now"
* to guint32 so that the sign bit doesn't get treated specially.
*
* Windows 8 provides GetSystemTimePreciseAsFileTime which we
* might want to use instead.
*/
GetSystemTimeAsFileTime(&now);
timestamp = (((guint64)(guint32)now.dwHighDateTime) << 32) +
(guint32)now.dwLowDateTime;
/*
* Convert to same thing but as 1-microsecond, i.e. 1000-nanosecond,
* intervals.
*/
timestamp /= 10;
/*
* Subtract difference, in microseconds, between January 1, 1601
* 00:00:00 UTC and January 1, 1970, 00:00:00 UTC.
*/
timestamp -= G_GUINT64_CONSTANT(11644473600000000);
#else
/*
* Current time, represented as seconds and microseconds since
* January 1, 1970, 00:00:00 UTC.
*/
gettimeofday(&now, NULL);
/*
* Convert to delta in microseconds.
*/
timestamp = (guint64)(now.tv_sec) * 1000000 +
(guint64)(now.tv_usec);
#endif
return timestamp;
}
static void
print_usage(FILE *output)
{
fprintf(output, "\nUsage: dumpcap [options] ...\n");
fprintf(output, "\n");
fprintf(output, "Capture interface:\n");
fprintf(output, " -i <interface> name or idx of interface (def: first non-loopback),\n"
" or for remote capturing, use one of these formats:\n"
" rpcap://<host>/<interface>\n"
" TCP@<host>:<port>\n");
fprintf(output, " -f <capture filter> packet filter in libpcap filter syntax\n");
fprintf(output, " -s <snaplen> packet snapshot length (def: 65535)\n");
fprintf(output, " -p don't capture in promiscuous mode\n");
#ifdef HAVE_PCAP_CREATE
fprintf(output, " -I capture in monitor mode, if available\n");
#endif
#if defined(_WIN32) || defined(HAVE_PCAP_CREATE)
fprintf(output, " -B <buffer size> size of kernel buffer in MiB (def: %dMiB)\n", DEFAULT_CAPTURE_BUFFER_SIZE);
#endif
fprintf(output, " -y <link type> link layer type (def: first appropriate)\n");
fprintf(output, " -D print list of interfaces and exit\n");
fprintf(output, " -L print list of link-layer types of iface and exit\n");
#ifdef HAVE_BPF_IMAGE
fprintf(output, " -d print generated BPF code for capture filter\n");
#endif
fprintf(output, " -k set channel on wifi interface <freq>,[<type>]\n");
fprintf(output, " -S print statistics for each interface once per second\n");
fprintf(output, " -M for -D, -L, and -S, produce machine-readable output\n");
fprintf(output, "\n");
#ifdef HAVE_PCAP_REMOTE
fprintf(output, "RPCAP options:\n");
fprintf(output, " -r don't ignore own RPCAP traffic in capture\n");
fprintf(output, " -u use UDP for RPCAP data transfer\n");
fprintf(output, " -A <user>:<password> use RPCAP password authentication\n");
#ifdef HAVE_PCAP_SETSAMPLING
fprintf(output, " -m <sampling type> use packet sampling\n");
fprintf(output, " count:NUM - capture one packet of every NUM\n");
fprintf(output, " timer:NUM - capture no more than 1 packet in NUM ms\n");
#endif
#endif
fprintf(output, "Stop conditions:\n");
fprintf(output, " -c <packet count> stop after n packets (def: infinite)\n");
fprintf(output, " -a <autostop cond.> ... duration:NUM - stop after NUM seconds\n");
fprintf(output, " filesize:NUM - stop this file after NUM KB\n");
fprintf(output, " files:NUM - stop after NUM files\n");
/*fprintf(output, "\n");*/
fprintf(output, "Output (files):\n");
fprintf(output, " -w <filename> name of file to save (def: tempfile)\n");
fprintf(output, " -g enable group read access on the output file(s)\n");
fprintf(output, " -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs\n");
fprintf(output, " filesize:NUM - switch to next file after NUM KB\n");
fprintf(output, " files:NUM - ringbuffer: replace after NUM files\n");
fprintf(output, " -n use pcapng format instead of pcap (default)\n");
fprintf(output, " -P use libpcap format instead of pcapng\n");
fprintf(output, " --capture-comment <comment>\n");
fprintf(output, " add a capture comment to the output file\n");
fprintf(output, " (only for pcapng)\n");
fprintf(output, "\n");
fprintf(output, "Miscellaneous:\n");
fprintf(output, " -N <packet_limit> maximum number of packets buffered within dumpcap\n");
fprintf(output, " -C <byte_limit> maximum number of bytes used for buffering packets\n");
fprintf(output, " within dumpcap\n");
fprintf(output, " -t use a separate thread per interface\n");
fprintf(output, " -q don't report packet capture counts\n");
fprintf(output, " -v print version information and exit\n");
fprintf(output, " -h display this help and exit\n");
fprintf(output, "\n");
#ifdef __linux__
fprintf(output, "WARNING: dumpcap will enable kernel BPF JIT compiler if available.\n");
fprintf(output, "You might want to reset it\n");
fprintf(output, "By doing \"echo 0 > /proc/sys/net/core/bpf_jit_enable\"\n");
fprintf(output, "\n");
#endif
fprintf(output, "Example: dumpcap -i eth0 -a duration:60 -w output.pcapng\n");
fprintf(output, "\"Capture packets from interface eth0 until 60s passed into output.pcapng\"\n");
fprintf(output, "\n");
fprintf(output, "Use Ctrl-C to stop capturing at any time.\n");
}
static void
show_version(GString *comp_info_str, GString *runtime_info_str)
{
printf("Dumpcap (Wireshark) %s\n"
"\n"
"%s"
"\n"
"%s"
"\n"
"%s",
get_ws_vcs_version_info(), get_copyright_info(), comp_info_str->str, runtime_info_str->str);
}
/*
* Report an error in command-line arguments.
* If we're a capture child, send a message back to the parent, otherwise
* just print it.
*/
static void
dumpcap_cmdarg_err(const char *fmt, va_list ap)
{
if (capture_child) {
gchar *msg;
/* Generate a 'special format' message back to parent */
msg = g_strdup_vprintf(fmt, ap);
sync_pipe_errmsg_to_parent(2, msg, "");
g_free(msg);
} else {
fprintf(stderr, "dumpcap: ");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}
}
/*
* Report additional information for an error in command-line arguments.
* If we're a capture child, send a message back to the parent, otherwise
* just print it.
*/
static void
dumpcap_cmdarg_err_cont(const char *fmt, va_list ap)
{
if (capture_child) {
gchar *msg;
msg = g_strdup_vprintf(fmt, ap);
sync_pipe_errmsg_to_parent(2, msg, "");
g_free(msg);
} else {
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}
}
#ifdef HAVE_LIBCAP
static void
#if 0 /* Set to enable capability debugging */
/* see 'man cap_to_text()' for explanation of output */
/* '=' means 'all= ' ie: no capabilities */
/* '=ip' means 'all=ip' ie: all capabilities are permissible and inheritable */
/* .... */
print_caps(const char *pfx) {
cap_t caps = cap_get_proc();
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"%s: EUID: %d Capabilities: %s", pfx,
geteuid(), cap_to_text(caps, NULL));
cap_free(caps);
#else
print_caps(const char *pfx _U_) {
#endif
}
static void
relinquish_all_capabilities(void)
{
/* Drop any and all capabilities this process may have. */
/* Allowed whether or not process has any privileges. */
cap_t caps = cap_init(); /* all capabilities initialized to off */
print_caps("Pre-clear");
if (cap_set_proc(caps)) {
cmdarg_err("cap_set_proc() fail return: %s", g_strerror(errno));
}
print_caps("Post-clear");
cap_free(caps);
}
#endif
static pcap_t *
open_capture_device(capture_options *capture_opts
#ifndef HAVE_PCAP_SET_TSTAMP_PRECISION
_U_
#endif
,
interface_options *interface_opts,
char (*open_err_str)[PCAP_ERRBUF_SIZE])
{
pcap_t *pcap_h;
#ifdef HAVE_PCAP_CREATE
int err;
#endif
#if defined(HAVE_PCAP_OPEN) && defined(HAVE_PCAP_REMOTE)
struct pcap_rmtauth auth;
#endif
/* Open the network interface to capture from it.
Some versions of libpcap may put warnings into the error buffer
if they succeed; to tell if that's happened, we have to clear
the error buffer, and check if it's still a null string. */
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "Entering open_capture_device().");
(*open_err_str)[0] = '\0';
#if defined(HAVE_PCAP_OPEN) && defined(HAVE_PCAP_REMOTE)
/*
* If we're opening a remote device, use pcap_open(); that's currently
* the only open routine that supports remote devices.
*/
if (strncmp (interface_opts->name, "rpcap://", 8) == 0) {
auth.type = interface_opts->auth_type == CAPTURE_AUTH_PWD ?
RPCAP_RMTAUTH_PWD : RPCAP_RMTAUTH_NULL;
auth.username = interface_opts->auth_username;
auth.password = interface_opts->auth_password;
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"Calling pcap_open() using name %s, snaplen %d, promisc_mode %d, datatx_udp %d, nocap_rpcap %d.",
interface_opts->name, interface_opts->snaplen, interface_opts->promisc_mode,
interface_opts->datatx_udp, interface_opts->nocap_rpcap);
pcap_h = pcap_open(interface_opts->name, interface_opts->snaplen,
/* flags */
(interface_opts->promisc_mode ? PCAP_OPENFLAG_PROMISCUOUS : 0) |
(interface_opts->datatx_udp ? PCAP_OPENFLAG_DATATX_UDP : 0) |
(interface_opts->nocap_rpcap ? PCAP_OPENFLAG_NOCAPTURE_RPCAP : 0),
CAP_READ_TIMEOUT, &auth, *open_err_str);
if (pcap_h == NULL) {
/* Error - did pcap actually supply an error message? */
if ((*open_err_str)[0] == '\0') {
/* Work around known WinPcap bug wherein no error message is
filled in on a failure to open an rpcap: URL. */
g_strlcpy(*open_err_str,
"Unknown error (pcap bug; actual error cause not reported)",
sizeof *open_err_str);
}
}
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"pcap_open() returned %p.", (void *)pcap_h);
} else
#endif
{
/*
* If we're not opening a remote device, use pcap_create() and
* pcap_activate() if we have them, so that we can set the buffer
* size, otherwise use pcap_open_live().
*/
#ifdef HAVE_PCAP_CREATE
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"Calling pcap_create() using %s.", interface_opts->name);
pcap_h = pcap_create(interface_opts->name, *open_err_str);
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"pcap_create() returned %p.", (void *)pcap_h);
if (pcap_h != NULL) {
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"Calling pcap_set_snaplen() with snaplen %d.", interface_opts->snaplen);
pcap_set_snaplen(pcap_h, interface_opts->snaplen);
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"Calling pcap_set_promisc() with promisc_mode %d.", interface_opts->promisc_mode);
pcap_set_promisc(pcap_h, interface_opts->promisc_mode);
pcap_set_timeout(pcap_h, CAP_READ_TIMEOUT);
#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
/*
* If we're writing pcap-ng files, try to enable
* nanosecond-resolution capture; any code that
* can read pcap-ng files must be able to handle
* nanosecond-resolution time stamps.
*
* If we're writing pcap files, don't try to enable
* nanosecond-resolution capture, as not all code
* that reads pcap files recognizes the nanosecond-
* resolution pcap file magic number.
*/
if (capture_opts->use_pcapng) {
/*
* The only errors this is documenting as returning
* are PCAP_ERROR_TSTAMP_PRECISION_NOTSUP, which just
* means we can't do nanosecond precision on this adapter,
* in which case we just live with whatever resolution
* we get by default, and PCAP_ERROR_ACTIVATED, which
* can't happen as we haven't activated the pcap_t yet.
*/
pcap_set_tstamp_precision(pcap_h, PCAP_TSTAMP_PRECISION_NANO);
}
#endif
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"buffersize %d.", interface_opts->buffer_size);
if (interface_opts->buffer_size != 0) {
pcap_set_buffer_size(pcap_h, interface_opts->buffer_size * 1024 * 1024);
}
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"monitor_mode %d.", interface_opts->monitor_mode);
if (interface_opts->monitor_mode)
pcap_set_rfmon(pcap_h, 1);
err = pcap_activate(pcap_h);
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"pcap_activate() returned %d.", err);
if (err < 0) {
/* Failed to activate, set to NULL */
if (err == PCAP_ERROR)
g_strlcpy(*open_err_str, pcap_geterr(pcap_h), sizeof *open_err_str);
else
g_strlcpy(*open_err_str, pcap_statustostr(err), sizeof *open_err_str);
pcap_close(pcap_h);
pcap_h = NULL;
}
}
#else
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"pcap_open_live() calling using name %s, snaplen %d, promisc_mode %d.",
interface_opts->name, interface_opts->snaplen, interface_opts->promisc_mode);
pcap_h = pcap_open_live(interface_opts->name, interface_opts->snaplen,
interface_opts->promisc_mode, CAP_READ_TIMEOUT,
*open_err_str);
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG,
"pcap_open_live() returned %p.", (void *)pcap_h);
#endif
}
g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "open_capture_device %s : %s", pcap_h ? "SUCCESS" : "FAILURE", interface_opts->name);
return pcap_h;
}
static void
get_capture_device_open_failure_messages(const char *open_err_str,
const char *iface,
char *errmsg, size_t errmsg_len,
char *secondary_errmsg,
size_t secondary_errmsg_len)
{
#ifndef _WIN32
const char *libpcap_warn;
static const char ppamsg[] = "can't find PPA for ";
#endif
g_snprintf(errmsg, (gulong) errmsg_len,
"The capture session could not be initiated on interface '%s' (%s).",
iface, open_err_str);
#ifdef _WIN32
if (!has_wpcap) {
g_snprintf(secondary_errmsg, (gulong) secondary_errmsg_len,
"\n"
"In order to capture packets, WinPcap must be installed; see\n"
"\n"
" http://www.winpcap.org/\n"
"\n"
"or the mirror at\n"
"\n"
" http://www.mirrors.wiretapped.net/security/packet-capture/winpcap/\n"
"\n"
"or the mirror at\n"
"\n"
" http://winpcap.cs.pu.edu.tw/\n"
"\n"
"for a downloadable version of WinPcap and for instructions on how to install\n"
"WinPcap.");
} else {
g_snprintf(secondary_errmsg, (gulong) secondary_errmsg_len,
"\n"
"Please check that \"%s\" is the proper interface.\n"
"\n"
"\n"
"Help can be found at:\n"
"\n"
" http://wiki.wireshark.org/WinPcap\n"
" http://wiki.wireshark.org/CaptureSetup\n",
iface);
}
#else
/* If we got a "can't find PPA for X" message, warn the user (who
is running dumpcap on HP-UX) that they don't have a version of
libpcap that properly handles HP-UX (libpcap 0.6.x and later
versions, which properly handle HP-UX, say "can't find /dev/dlpi
PPA for X" rather than "can't find PPA for X"). */
if (strncmp(open_err_str, ppamsg, sizeof ppamsg - 1) == 0)
libpcap_warn =
"\n\n"
"You are running (T)Wireshark with a version of the libpcap library\n"
"that doesn't handle HP-UX network devices well; this means that\n"
"(T)Wireshark may not be able to capture packets.\n"
"\n"
"To fix this, you should install libpcap 0.6.2, or a later version\n"
"of libpcap, rather than libpcap 0.4 or 0.5.x. It is available in\n"
"packaged binary form from the Software Porting And Archive Centre\n"
"for HP-UX; the Centre is at http://hpux.connect.org.uk/ - the page\n"
"at the URL lists a number of mirror sites.";
else
libpcap_warn = "";
g_snprintf(secondary_errmsg, (gulong) secondary_errmsg_len,
"Please check to make sure you have sufficient permissions, and that you have "
"the proper interface or pipe specified.%s", libpcap_warn);
#endif /* _WIN32 */
}
/* Set the data link type on a pcap. */
static gboolean
set_pcap_linktype(pcap_t *pcap_h, int linktype, char *name,
char *errmsg, size_t errmsg_len,
char *secondary_errmsg, size_t secondary_errmsg_len)
{
char *set_linktype_err_str;
if (linktype == -1)
return TRUE; /* just use the default */
#ifdef HAVE_PCAP_SET_DATALINK
if (pcap_set_datalink(pcap_h, linktype) == 0)
return TRUE; /* no error */
set_linktype_err_str = pcap_geterr(pcap_h);
#else
/* Let them set it to the type it is; reject any other request. */
if (get_pcap_linktype(pcap_h, name) == linktype)
return TRUE; /* no error */
set_linktype_err_str =
"That DLT isn't one of the DLTs supported by this device";
#endif
g_snprintf(errmsg, (gulong) errmsg_len, "Unable to set data link type on interface '%s' (%s).",
name, set_linktype_err_str);
/*
* If the error isn't "XXX is not one of the DLTs supported by this device",
* tell the user to tell the Wireshark developers about it.
*/
if (strstr(set_linktype_err_str, "is not one of the DLTs supported by this device") == NULL)
g_snprintf(secondary_errmsg, (gulong) secondary_errmsg_len, please_report);
else
secondary_errmsg[0] = '\0';
return FALSE;
}
static gboolean
compile_capture_filter(const char *iface, pcap_t *pcap_h,
struct bpf_program *fcode, const char *cfilter)
{
bpf_u_int32 netnum, netmask;
gchar lookup_net_err_str[PCAP_ERRBUF_SIZE];
if (pcap_lookupnet(iface, &netnum, &netmask, lookup_net_err_str) < 0) {
/*
* Well, we can't get the netmask for this interface; it's used
* only for filters that check for broadcast IP addresses, so
* we just punt and use 0. It might be nice to warn the user,
* but that's a pain in a GUI application, as it'd involve popping
* up a message box, and it's not clear how often this would make
* a difference (only filters that check for IP broadcast addresses
* use the netmask).
*/
/*cmdarg_err(
"Warning: Couldn't obtain netmask info (%s).", lookup_net_err_str);*/
netmask = 0;
}
/*
* Sigh. Older versions of libpcap don't properly declare the
* third argument to pcap_compile() as a const pointer. Cast
* away the warning.
*/
if (pcap_compile(pcap_h, fcode, (char *)cfilter, 1, netmask) < 0)
return FALSE;
return TRUE;
}
#ifdef HAVE_BPF_IMAGE
static gboolean
show_filter_code(capture_options *capture_opts)
{
interface_options interface_opts;
pcap_t *pcap_h;
gchar open_err_str[PCAP_ERRBUF_SIZE];
char errmsg[MSG_MAX_LENGTH+1];
char secondary_errmsg[MSG_MAX_LENGTH+1];
struct bpf_program fcode;
struct bpf_insn *insn;
u_int i;
guint j;
for (j = 0; j < capture_opts->ifaces->len; j++) {
interface_opts = g_array_index(capture_opts->ifaces, interface_options, j);
pcap_h = open_capture_device(capture_opts, &interface_opts, &open_err_str);
if (pcap_h == NULL) {
/* Open failed; get messages */
get_capture_device_open_failure_messages(open_err_str,
interface_opts.name,
errmsg, sizeof errmsg,
secondary_errmsg,
sizeof secondary_errmsg);
/* And report them */
report_capture_error(errmsg, secondary_errmsg);
return FALSE;
}
/* Set the link-layer type. */
if (!set_pcap_linktype(pcap_h, interface_opts.linktype, interface_opts.name,
errmsg, sizeof errmsg,
secondary_errmsg, sizeof secondary_errmsg)) {
pcap_close(pcap_h);
report_capture_error(errmsg, secondary_errmsg);
return FALSE;
}
/* OK, try to compile the capture filter. */
if (!compile_capture_filter(interface_opts.name, pcap_h, &fcode,
interface_opts.cfilter)) {
pcap_close(pcap_h);
report_cfilter_error(capture_opts, j, errmsg);
return FALSE;
}
pcap_close(pcap_h);
/* Now print the filter code. */
insn = fcode.bf_insns;
for (i = 0; i < fcode.bf_len; insn++, i++)
printf("%s\n", bpf_image(insn, i));
}
/* If not using libcap: we now can now set euid/egid to ruid/rgid */
/* to remove any suid privileges. */
/* If using libcap: we can now remove NET_RAW and NET_ADMIN capabilities */
/* (euid/egid have already previously been set to ruid/rgid. */
/* (See comment in main() for details) */
#ifndef HAVE_LIBCAP
relinquish_special_privs_perm();
#else
relinquish_all_capabilities();
#endif
if (capture_child) {
/* Let our parent know we succeeded. */
pipe_write_block(2, SP_SUCCESS, NULL);
}
return TRUE;
}
#endif
/*
* capture_interface_list() is expected to do the right thing to get
* a list of interfaces.
*
* In most of the programs in the Wireshark suite, "the right thing"
* is to run dumpcap and ask it for the list, because dumpcap may
* be the only program in the suite with enough privileges to get
* the list.