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wireshark/capture.c

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/* capture.c
* Routines for packet capture
*
* $Id$
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* 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_IO_H
# include <io.h>
#endif
#include <signal.h>
#include <errno.h>
#include <pcap.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/dfilter/dfilter.h>
#include "file.h"
#include "capture.h"
#include "capture_sync.h"
#include "capture_ui_utils.h"
#include "util.h"
#include "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 "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;
}
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);
}
return ret;
}
void
capture_stop(capture_options *capture_opts)
{
g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Stop ...");
/* 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_MESSAGE, "Capture Kill");
/* kill the capture child */
sync_pipe_kill(capture_opts);
}
/* 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_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!",
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) */
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;
}
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.
XXX - do something if this fails? */
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);
main_window_update();
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;
}
}
}
/* capture child closed it's side ot the pipe, do the required cleanup */
void
capture_input_closed(capture_options *capture_opts)
{
int err;
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 (happens if an error occured), do a fake start */
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) {
/* first of all, we are not doing a capture any more */
cf_callback_invoke(cf_cb_live_capture_update_finished, capture_opts->cf);
/* Read what remains of the capture file, and finish the capture.
XXX - do something if this fails? */
switch (cf_finish_tail(capture_opts->cf, &err)) {
case CF_READ_OK:
if(cf_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!",
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));
}
}
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;
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;
}
}
#endif /* HAVE_LIBPCAP */
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