/* capture.c * Routines for packet capture * * $Id$ * * Wireshark - Network traffic analyzer * By Gerald Combs * 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 #endif #include #include #include #include #include #include "file.h" #include "capture.h" #include "capture_ifinfo.h" #include "capture_sync.h" #include "capture_info.h" #include "capture_ui_utils.h" #include "util.h" #include "capture-pcap-util.h" #include "simple_dialog.h" #include #ifdef _WIN32 #include "capture-wpcap.h" #endif #include "ui_util.h" #include "wsutil/file_util.h" #include "log.h" typedef struct if_stat_cache_item_s { char *name; struct pcap_stat ps; } if_stat_cache_item_t; struct if_stat_cache_s { int stat_fd; int fork_child; GList *cache_list; /* List of if_stat_chache_entry_t */ }; /* this callback mechanism should possibly be replaced by the g_signal_...() stuff (if I only would know how :-) */ typedef struct { capture_callback_t cb_fct; gpointer user_data; } capture_callback_data_t; static GList *capture_callbacks = NULL; static void capture_callback_invoke(int event, capture_options *capture_opts) { capture_callback_data_t *cb; GList *cb_item = capture_callbacks; /* there should be at least one interested */ g_assert(cb_item != NULL); while(cb_item != NULL) { cb = cb_item->data; cb->cb_fct(event, capture_opts, cb->user_data); cb_item = g_list_next(cb_item); } } void capture_callback_add(capture_callback_t func, gpointer user_data) { capture_callback_data_t *cb; cb = g_malloc(sizeof(capture_callback_data_t)); cb->cb_fct = func; cb->user_data = user_data; capture_callbacks = g_list_append(capture_callbacks, cb); } void capture_callback_remove(capture_callback_t func) { capture_callback_data_t *cb; GList *cb_item = capture_callbacks; while(cb_item != NULL) { cb = cb_item->data; if(cb->cb_fct == func) { capture_callbacks = g_list_remove(capture_callbacks, cb); g_free(cb); return; } cb_item = g_list_next(cb_item); } g_assert_not_reached(); } /** * Start a capture. * * @return TRUE if the capture starts successfully, FALSE otherwise. */ gboolean capture_start(capture_options *capture_opts) { gboolean ret; GString *source = g_string_new(""); /* 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 ..."); g_string_printf(source, "%s", get_iface_description(capture_opts)); if(capture_opts->cfilter && capture_opts->cfilter[0]) { g_string_append_printf(source, " (%s)", capture_opts->cfilter); } cf_set_tempfile_source(capture_opts->cf, source->str); g_string_free(source, TRUE); /* 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 */ /* (for example: it will block if no input arrives from an input capture pipe (e.g. mkfifo)) */ /* to prevent problems, bring the main GUI into "capture mode" right after a successful */ /* spawn/exec of the capture child, without waiting for any response from it */ capture_callback_invoke(capture_cb_capture_prepared, capture_opts); if(capture_opts->show_info) capture_info_open(capture_opts); } return ret; } void capture_stop(capture_options *capture_opts) { g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Stop ..."); capture_callback_invoke(capture_cb_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 in doing 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, FALSE)) { 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 capture 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) { capture_callback_invoke(capture_cb_capture_update_finished, capture_opts); 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 have 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; } } if(capture_opts->show_info) { if (!capture_info_new_file(new_file)) return FALSE; } if(capture_opts->real_time_mode) { capture_callback_invoke(capture_cb_capture_update_started, capture_opts); } else { capture_callback_invoke(capture_cb_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? */ capture_callback_invoke(capture_cb_capture_update_continue, capture_opts); 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 the capture file packet counter by the number of incoming packets */ cf_set_packet_count(capture_opts->cf, cf_get_packet_count(capture_opts->cf) + to_read); capture_callback_invoke(capture_cb_capture_fixed_continue, capture_opts); } /* 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, guint32 dropped) { g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_INFO, "%u 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 start 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) { capture_callback_invoke(capture_cb_capture_update_started, capture_opts); } else { capture_callback_invoke(capture_cb_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 correctly displayed */ capture_callback_invoke(capture_cb_capture_update_finished, capture_opts); /* 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 */ capture_callback_invoke(capture_cb_capture_fixed_finished, capture_opts); /* 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; ws_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; } } if_stat_cache_t * capture_stat_start(GList *if_list) { int stat_fd, fork_child; gchar *msg; if_stat_cache_t *sc = NULL; GList *if_entry; if_info_t *if_info; if_stat_cache_item_t *sc_item; /* Fire up dumpcap. */ /* * XXX - on systems with BPF, the number of BPF devices limits the * number of devices on which you can capture simultaneously. * * This means that * * 1) this might fail if you run out of BPF devices * * and * * 2) opening every interface could leave too few BPF devices * for *other* programs. * * It also means the system could end up getting a lot of traffic * that it has to pass through the networking stack and capture * mechanism, so opening all the devices and presenting packet * counts might not always be a good idea. */ if (sync_interface_stats_open(&stat_fd, &fork_child, &msg) == 0) { sc = g_malloc(sizeof(if_stat_cache_t)); sc->stat_fd = stat_fd; sc->fork_child = fork_child; sc->cache_list = NULL; /* Initialize the cache */ for (if_entry = if_list; if_entry != NULL; if_entry = g_list_next(if_entry)) { if_info = if_entry->data; sc_item = g_malloc0(sizeof(if_stat_cache_item_t)); sc_item->name = g_strdup(if_info->name); sc->cache_list = g_list_append(sc->cache_list, sc_item); } } return sc; } #define MAX_STAT_LINE_LEN 500 static void capture_stat_cache_update(if_stat_cache_t *sc) { gchar stat_line[MAX_STAT_LINE_LEN]; gchar **stat_parts; GList *sc_entry; if_stat_cache_item_t *sc_item; if (!sc) return; while (sync_pipe_gets_nonblock(sc->stat_fd, stat_line, MAX_STAT_LINE_LEN) > 0) { g_strstrip(stat_line); stat_parts = g_strsplit(stat_line, "\t", 3); if (stat_parts[0] == NULL || stat_parts[1] == NULL || stat_parts[2] == NULL) { g_strfreev(stat_parts); continue; } for (sc_entry = sc->cache_list; sc_entry != NULL; sc_entry = g_list_next(sc_entry)) { sc_item = sc_entry->data; if (strcmp(sc_item->name, stat_parts[0]) == 0) { sc_item->ps.ps_recv = (u_int) strtoul(stat_parts[1], NULL, 10); sc_item->ps.ps_drop = (u_int) strtoul(stat_parts[2], NULL, 10); } } g_strfreev(stat_parts); } } gboolean capture_stats(if_stat_cache_t *sc, char *ifname, struct pcap_stat *ps) { GList *sc_entry; if_stat_cache_item_t *sc_item; if (!sc || !ifname || !ps) { return FALSE; } capture_stat_cache_update(sc); for (sc_entry = sc->cache_list; sc_entry != NULL; sc_entry = g_list_next(sc_entry)) { sc_item = sc_entry->data; if (strcmp(sc_item->name, ifname) == 0) { memcpy(ps, &sc_item->ps, sizeof(struct pcap_stat)); return TRUE; } } return FALSE; } void capture_stat_stop(if_stat_cache_t *sc) { GList *sc_entry; if_stat_cache_item_t *sc_item; gchar *msg; if (!sc) return; sync_interface_stats_close(&sc->stat_fd, &sc->fork_child, &msg); for (sc_entry = sc->cache_list; sc_entry != NULL; sc_entry = g_list_next(sc_entry)) { sc_item = sc_entry->data; g_free(sc_item->name); g_free(sc_item); } g_free(sc); } #endif /* HAVE_LIBPCAP */