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wireshark/capture.c

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/* capture.c
* Routines for packet capture
*
* $Id$
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_LIBPCAP
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#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_SOCKET_H
#include <sys/socket.h> /* needed to define AF_ values on UNIX */
#endif
#ifdef HAVE_WINSOCK2_H
#include <winsock2.h> /* needed to define AF_ values on Windows */
#endif
#ifdef NEED_INET_V6DEFS_H
# include "inet_v6defs.h"
#endif
#include <signal.h>
#include <errno.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/dfilter/dfilter.h>
#include <epan/ws_strsplit.h>
#include "file.h"
#include "capture.h"
#include "capture_sync.h"
#include "capture_info.h"
#include "capture_ui_utils.h"
#include "util.h"
#include "capture-pcap-util.h"
#include "alert_box.h"
#include "simple_dialog.h"
#include <epan/prefs.h>
#include "conditions.h"
#include "ringbuffer.h"
#ifdef _WIN32
#include "capture-wpcap.h"
#endif
#include "ui_util.h"
#include "file_util.h"
#include "log.h"
/**
* Start a capture.
*
* @return TRUE if the capture starts successfully, FALSE otherwise.
*/
gboolean
capture_start(capture_options *capture_opts)
{
gboolean ret;
/* close the currently loaded capture file */
cf_close(capture_opts->cf);
g_assert(capture_opts->state == CAPTURE_STOPPED);
capture_opts->state = CAPTURE_PREPARING;
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Start ...");
/* try to start the capture child process */
ret = sync_pipe_start(capture_opts);
if(!ret) {
if(capture_opts->save_file != NULL) {
g_free(capture_opts->save_file);
capture_opts->save_file = NULL;
}
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Start failed!");
capture_opts->state = CAPTURE_STOPPED;
} else {
/* the capture child might not respond shortly after bringing it up */
/* (especially it will block, if no input coming from an input capture pipe (e.g. mkfifo) is coming in) */
/* to prevent problems, bring the main GUI into "capture mode" right after successfully */
/* spawn/exec the capture child, without waiting for any response from it */
cf_callback_invoke(cf_cb_live_capture_prepared, capture_opts);
if(capture_opts->show_info)
capture_info_open(capture_opts->iface);
}
return ret;
}
void
capture_stop(capture_options *capture_opts)
{
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Stop ...");
cf_callback_invoke(cf_cb_live_capture_stopping, capture_opts);
/* stop the capture child gracefully */
sync_pipe_stop(capture_opts);
}
void
capture_restart(capture_options *capture_opts)
{
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Restart");
capture_opts->restart = TRUE;
capture_stop(capture_opts);
}
void
capture_kill_child(capture_options *capture_opts)
{
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_INFO, "Capture Kill");
/* kill the capture child */
sync_pipe_kill(capture_opts->fork_child);
}
/* We've succeeded a (non real-time) capture, try to read it into a new capture file */
static gboolean
capture_input_read_all(capture_options *capture_opts, gboolean is_tempfile, gboolean drops_known,
guint32 drops)
{
int err;
/* Capture succeeded; attempt to open the capture file. */
if (cf_open(capture_opts->cf, capture_opts->save_file, is_tempfile, &err) != CF_OK) {
/* We're not doing a capture any more, so we don't have a save
file. */
return FALSE;
}
/* Set the read filter to NULL. */
/* XXX - this is odd here, try to put it somewhere, where it fits better */
cf_set_rfcode(capture_opts->cf, NULL);
/* Get the packet-drop statistics.
XXX - there are currently no packet-drop statistics stored
in libpcap captures, and that's what we're reading.
At some point, we will add support in Wiretap to return
packet-drop statistics for capture file formats that store it,
and will make "cf_read()" get those statistics from Wiretap.
We clear the statistics (marking them as "not known") in
"cf_open()", and "cf_read()" will only fetch them and mark
them as known if Wiretap supplies them, so if we get the
statistics now, after calling "cf_open()" but before calling
"cf_read()", the values we store will be used by "cf_read()".
If a future libpcap capture file format stores the statistics,
we'll put them into the capture file that we write, and will
thus not have to set them here - "cf_read()" will get them from
the file and use them. */
if (drops_known) {
cf_set_drops_known(capture_opts->cf, TRUE);
/* XXX - on some systems, libpcap doesn't bother filling in
"ps_ifdrop" - it doesn't even set it to zero - so we don't
bother looking at it.
Ideally, libpcap would have an interface that gave us
several statistics - perhaps including various interface
error statistics - and would tell us which of them it
supplies, allowing us to display only the ones it does. */
cf_set_drops(capture_opts->cf, drops);
}
/* read in the packet data */
switch (cf_read(capture_opts->cf)) {
case CF_READ_OK:
case CF_READ_ERROR:
/* Just because we got an error, that doesn't mean we were unable
to read any of the file; we handle what we could get from the
file. */
break;
case CF_READ_ABORTED:
/* User wants to quit program. Exit by leaving the main loop,
so that any quit functions we registered get called. */
main_window_nested_quit();
return FALSE;
}
/* if we didn't captured even a single packet, close the file again */
if(cf_get_packet_count(capture_opts->cf) == 0 && !capture_opts->restart) {
simple_dialog(ESD_TYPE_INFO, ESD_BTN_OK,
"%sNo packets captured!%s\n"
"\n"
"As no data was captured, closing the %scapture file!\n"
"\n"
"\n"
"Help about capturing can be found at:\n"
"\n"
" http://wiki.wireshark.org/CaptureSetup"
#ifdef _WIN32
"\n\n"
"Wireless (Wi-Fi/WLAN):\n"
"Try to switch off promiscuous mode in the Capture Options!"
#endif
"",
simple_dialog_primary_start(), simple_dialog_primary_end(),
(cf_is_tempfile(capture_opts->cf)) ? "temporary " : "");
cf_close(capture_opts->cf);
}
return TRUE;
}
/* capture child tells us we have a new (or the first) capture file */
gboolean
capture_input_new_file(capture_options *capture_opts, gchar *new_file)
{
gboolean is_tempfile;
int err;
if(capture_opts->state == CAPTURE_PREPARING) {
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture started!");
}
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "File: \"%s\"", new_file);
g_assert(capture_opts->state == CAPTURE_PREPARING || capture_opts->state == CAPTURE_RUNNING);
/* free the old filename */
if(capture_opts->save_file != NULL) {
/* we start a new capture file, close the old one (if we had one before) */
/* (we can only have an open capture file in real_time_mode!) */
if( ((capture_file *) capture_opts->cf)->state != FILE_CLOSED) {
cf_callback_invoke(cf_cb_live_capture_update_finished, capture_opts->cf);
cf_finish_tail(capture_opts->cf, &err);
cf_close(capture_opts->cf);
}
g_free(capture_opts->save_file);
is_tempfile = FALSE;
cf_set_tempfile(capture_opts->cf, FALSE);
} else {
/* we didn't had a save_file before, must be a tempfile */
is_tempfile = TRUE;
cf_set_tempfile(capture_opts->cf, TRUE);
}
/* save the new filename */
capture_opts->save_file = g_strdup(new_file);
/* if we are in real-time mode, open the new file now */
if(capture_opts->real_time_mode) {
/* Attempt to open the capture file and set up to read from it. */
switch(cf_start_tail(capture_opts->cf, capture_opts->save_file, is_tempfile, &err)) {
case CF_OK:
break;
case CF_ERROR:
/* Don't unlink (delete) the save file - leave it around,
for debugging purposes. */
g_free(capture_opts->save_file);
capture_opts->save_file = NULL;
return FALSE;
break;
}
}
if(capture_opts->show_info) {
if (!capture_info_new_file(new_file))
return FALSE;
}
if(capture_opts->real_time_mode) {
cf_callback_invoke(cf_cb_live_capture_update_started, capture_opts);
} else {
cf_callback_invoke(cf_cb_live_capture_fixed_started, capture_opts);
}
capture_opts->state = CAPTURE_RUNNING;
return TRUE;
}
/* capture child tells us we have new packets to read */
void
capture_input_new_packets(capture_options *capture_opts, int to_read)
{
int err;
g_assert(capture_opts->save_file);
if(capture_opts->real_time_mode) {
/* Read from the capture file the number of records the child told us it added. */
switch (cf_continue_tail(capture_opts->cf, to_read, &err)) {
case CF_READ_OK:
case CF_READ_ERROR:
/* Just because we got an error, that doesn't mean we were unable
to read any of the file; we handle what we could get from the
file.
XXX - abort on a read error? */
cf_callback_invoke(cf_cb_live_capture_update_continue, capture_opts->cf);
break;
case CF_READ_ABORTED:
/* Kill the child capture process; the user wants to exit, and we
shouldn't just leave it running. */
capture_kill_child(capture_opts);
break;
}
} else {
/* increase capture file packet counter by the number or incoming packets */
cf_set_packet_count(capture_opts->cf,
cf_get_packet_count(capture_opts->cf) + to_read);
cf_callback_invoke(cf_cb_live_capture_fixed_continue, capture_opts->cf);
}
/* update the main window, so we get events (e.g. from the stop toolbar button) */
main_window_update();
if(capture_opts->show_info)
capture_info_new_packets(to_read);
}
/* Capture child told us how many dropped packets it counted.
*/
void
capture_input_drops(capture_options *capture_opts, int dropped)
{
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_INFO, "%d packet%s dropped", dropped, plurality(dropped, "", "s"));
g_assert(capture_opts->state == CAPTURE_RUNNING);
cf_set_drops_known(capture_opts->cf, TRUE);
cf_set_drops(capture_opts->cf, dropped);
}
/* Capture child told us that an error has occurred while starting/running
the capture.
The buffer we're handed has *two* null-terminated strings in it - a
primary message and a secondary message, one right after the other.
The secondary message might be a null string.
*/
void
capture_input_error_message(capture_options *capture_opts, char *error_msg, char *secondary_error_msg)
{
gchar *safe_error_msg;
gchar *safe_secondary_error_msg;
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Error message from child: \"%s\", \"%s\"",
error_msg, secondary_error_msg);
g_assert(capture_opts->state == CAPTURE_PREPARING || capture_opts->state == CAPTURE_RUNNING);
safe_error_msg = simple_dialog_format_message(error_msg);
if (*secondary_error_msg != '\0') {
/* We have both primary and secondary messages. */
safe_secondary_error_msg = simple_dialog_format_message(secondary_error_msg);
simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s%s%s\n\n%s",
simple_dialog_primary_start(), safe_error_msg,
simple_dialog_primary_end(), safe_secondary_error_msg);
g_free(safe_secondary_error_msg);
} else {
/* We have only a primary message. */
simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s%s%s",
simple_dialog_primary_start(), safe_error_msg,
simple_dialog_primary_end());
}
g_free(safe_error_msg);
/* the capture child will close the sync_pipe if required, nothing to do for now */
}
/* Capture child told us that an error has occurred while parsing a
capture filter when starting/running the capture.
*/
void
capture_input_cfilter_error_message(capture_options *capture_opts, char *error_message)
{
dfilter_t *rfcode = NULL;
gchar *safe_cfilter = simple_dialog_format_message(capture_opts->cfilter);
gchar *safe_cfilter_error_msg = simple_dialog_format_message(error_message);
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture filter error message from child: \"%s\"", error_message);
g_assert(capture_opts->state == CAPTURE_PREPARING || capture_opts->state == CAPTURE_RUNNING);
/* Did the user try a display filter? */
if (dfilter_compile(capture_opts->cfilter, &rfcode) && rfcode != NULL) {
simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
"%sInvalid capture filter: \"%s\"!%s\n"
"\n"
"That string looks like a valid display filter; however, it isn't a valid\n"
"capture filter (%s).\n"
"\n"
"Note that display filters and capture filters don't have the same syntax,\n"
"so you can't use most display filter expressions as capture filters.\n"
"\n"
"See the User's Guide for a description of the capture filter syntax.",
simple_dialog_primary_start(), safe_cfilter,
simple_dialog_primary_end(), safe_cfilter_error_msg);
dfilter_free(rfcode);
} else {
simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
"%sInvalid capture filter: \"%s\"!%s\n"
"\n"
"That string isn't a valid capture filter (%s).\n"
"See the User's Guide for a description of the capture filter syntax.",
simple_dialog_primary_start(), safe_cfilter,
simple_dialog_primary_end(), safe_cfilter_error_msg);
}
g_free(safe_cfilter_error_msg);
g_free(safe_cfilter);
/* the capture child will close the sync_pipe if required, nothing to do for now */
}
/* capture child closed its side of the pipe, do the required cleanup */
void
capture_input_closed(capture_options *capture_opts)
{
int err;
int packet_count_save;
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture stopped!");
g_assert(capture_opts->state == CAPTURE_PREPARING || capture_opts->state == CAPTURE_RUNNING);
/* if we didn't started the capture, do a fake start */
/* (happens if we got an error message - we won't get a filename then) */
if(capture_opts->state == CAPTURE_PREPARING) {
if(capture_opts->real_time_mode) {
cf_callback_invoke(cf_cb_live_capture_update_started, capture_opts);
} else {
cf_callback_invoke(cf_cb_live_capture_fixed_started, capture_opts);
}
}
if(capture_opts->real_time_mode) {
cf_read_status_t status;
/* Read what remains of the capture file. */
status = cf_finish_tail(capture_opts->cf, &err);
/* XXX: If -Q (quit-after-cap) then cf->count clr'd below so save it first */
packet_count_save = cf_get_packet_count(capture_opts->cf);
/* Tell the GUI, we are not doing a capture any more.
Must be done after the cf_finish_tail(), so file lengths are displayed
correct. */
cf_callback_invoke(cf_cb_live_capture_update_finished, capture_opts->cf);
/* Finish the capture. */
switch (status) {
case CF_READ_OK:
if ((packet_count_save == 0) && !capture_opts->restart) {
simple_dialog(ESD_TYPE_INFO, ESD_BTN_OK,
"%sNo packets captured!%s\n"
"\n"
"As no data was captured, closing the %scapture file!\n"
"\n"
"\n"
"Help about capturing can be found at:\n"
"\n"
" http://wiki.wireshark.org/CaptureSetup"
#ifdef _WIN32
"\n\n"
"Wireless (Wi-Fi/WLAN):\n"
"Try to switch off promiscuous mode in the Capture Options!"
#endif
"",
simple_dialog_primary_start(), simple_dialog_primary_end(),
cf_is_tempfile(capture_opts->cf) ? "temporary " : "");
cf_close(capture_opts->cf);
}
break;
case CF_READ_ERROR:
/* Just because we got an error, that doesn't mean we were unable
to read any of the file; we handle what we could get from the
file. */
break;
case CF_READ_ABORTED:
/* Exit by leaving the main loop, so that any quit functions
we registered get called. */
main_window_quit();
}
} else {
/* first of all, we are not doing a capture any more */
cf_callback_invoke(cf_cb_live_capture_fixed_finished, capture_opts->cf);
/* this is a normal mode capture and if no error happened, read in the capture file data */
if(capture_opts->save_file != NULL) {
capture_input_read_all(capture_opts, cf_is_tempfile(capture_opts->cf),
cf_get_drops_known(capture_opts->cf), cf_get_drops(capture_opts->cf));
}
}
if(capture_opts->show_info)
capture_info_close();
capture_opts->state = CAPTURE_STOPPED;
/* if we couldn't open a capture file, there's nothing more for us to do */
if(capture_opts->save_file == NULL) {
cf_close(capture_opts->cf);
return;
}
/* does the user wants to restart the current capture? */
if(capture_opts->restart) {
capture_opts->restart = FALSE;
eth_unlink(capture_opts->save_file);
/* if it was a tempfile, throw away the old filename (so it will become a tempfile again) */
if(cf_is_tempfile(capture_opts->cf)) {
g_free(capture_opts->save_file);
capture_opts->save_file = NULL;
}
/* ... and start the capture again */
capture_start(capture_opts);
} else {
/* We're not doing a capture any more, so we don't have a save file. */
g_free(capture_opts->save_file);
capture_opts->save_file = NULL;
}
}
/**
* Fetch the interface list from a child process (dumpcap).
*
* @return A GList containing if_info_t structs if successful, NULL otherwise.
*/
/* XXX - We parse simple text output to get our interface list. Should
* we use "real" data serialization instead, e.g. via XML? */
GList *
capture_interface_list(int *err, char **err_str)
{
GList *if_list = NULL;
int i, j;
gchar *msg;
gchar **raw_list, **if_parts, **addr_parts;
gchar *name;
if_info_t *if_info;
if_addr_t *if_addr;
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Interface List ...");
/* Try to get our interface list */
*err = sync_interface_list_open(&msg);
if (*err != 0) {
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Interface List failed!");
if (err_str) {
if (*err_str)
*err_str = msg;
else
g_free(msg);
} else {
g_free(msg);
}
return NULL;
}
/* Split our lines */
raw_list = g_strsplit(msg, "\n", 0);
g_free(msg);
for (i = 0; raw_list[i] != NULL; i++) {
if_parts = g_strsplit(raw_list[i], "\t", 4);
if (if_parts[0] == NULL || if_parts[1] == NULL || if_parts[2] == NULL ||
if_parts[3] == NULL) {
g_strfreev(if_parts);
continue;
}
/* Number followed by the name, e.g "1. eth0" */
name = strchr(if_parts[0], ' ');
if (name) {
name++;
} else {
g_strfreev(if_parts);
continue;
}
if_info = g_malloc0(sizeof(if_info_t));
if_info->name = g_strdup(name);
if (strlen(if_parts[1]) > 0)
if_info->description = g_strdup(if_parts[1]);
addr_parts = g_strsplit(if_parts[2], ",", 0);
for (j = 0; addr_parts[j] != NULL; j++) {
if_addr = g_malloc0(sizeof(if_addr_t));
if (inet_pton(AF_INET, addr_parts[j], &if_addr->ip_addr.ip4_addr)) {
if_addr->type = AT_IPv4;
} else if (inet_pton(AF_INET6, addr_parts[j],
&if_addr->ip_addr.ip6_addr)) {
if_addr->type = AT_IPv6;
} else {
g_free(if_addr);
if_addr = NULL;
}
if (if_addr) {
if_info->ip_addr = g_slist_append(if_info->ip_addr, if_addr);
}
}
if (strcmp(if_parts[3], "loopback") == 0)
if_info->loopback = TRUE;
g_strfreev(if_parts);
g_strfreev(addr_parts);
if_list = g_list_append(if_list, if_info);
}
g_strfreev(raw_list);
/* Check to see if we built a list */
if (if_list == NULL) {
if (*err_str)
*err_str = g_strdup("No interfaces found");
*err = NO_INTERFACES_FOUND;
}
return if_list;
}
/* XXX - We parse simple text output to get our interface list. Should
* we use "real" data serialization instead, e.g. via XML? */
GList *
capture_pcap_linktype_list(gchar *ifname, char **err_str)
{
GList *linktype_list = NULL;
int err, i;
gchar *msg;
gchar **raw_list, **lt_parts;
data_link_info_t *data_link_info;
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Interface List ...");
/* Try to get our interface list */
err = sync_linktype_list_open(ifname, &msg);
if (err != 0) {
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Interface List failed!");
if (err_str) {
*err_str = msg;
} else {
g_free(msg);
}
return NULL;
}
/* Split our lines */
raw_list = g_strsplit(msg, "\n", 0);
g_free(msg);
for (i = 0; raw_list[i] != NULL; i++) {
/* ...and what if the interface name has a tab in it, Mr. Clever Programmer? */
lt_parts = g_strsplit(raw_list[i], "\t", 3);
if (lt_parts[0] == NULL || lt_parts[1] == NULL || lt_parts[2] == NULL) {
g_strfreev(lt_parts);
continue;
}
data_link_info = g_malloc(sizeof (data_link_info_t));
data_link_info->dlt = (int) strtol(lt_parts[0], NULL, 10);
data_link_info->name = g_strdup(lt_parts[1]);
if (strcmp(lt_parts[2], "(not supported)") != NULL)
data_link_info->description = g_strdup(lt_parts[2]);
else
data_link_info->description = NULL;
linktype_list = g_list_append(linktype_list, data_link_info);
}
g_strfreev(raw_list);
/* Check to see if we built a list */
if (linktype_list == NULL) {
if (err_str)
*err_str = NULL;
}
return linktype_list;
}
#endif /* HAVE_LIBPCAP */
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