Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 993 insertions, 0 deletions

diff --git a/ui/capture.c b/ui/capture.c
new file mode 100644
index 00000000..62c8df7e
--- /dev/null
+++ b/ui/capture.c
@@ -0,0 +1,993 @@
+/* capture.c
+ * Routines for packet capture
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+#define WS_LOG_DOMAIN LOG_DOMAIN_CAPTURE
+
+#ifdef HAVE_LIBPCAP
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/dfilter/dfilter.h>
+#include "extcap.h"
+#include "file.h"
+#include "ui/capture.h"
+#include "capture/capture_ifinfo.h"
+#include <capture/capture_sync.h>
+#include "ui/capture_info.h"
+#include "ui/capture_ui_utils.h"
+#include "ui/util.h"
+#include "ui/urls.h"
+#include "capture/capture-pcap-util.h"
+
+#ifdef _WIN32
+#include "capture/capture-wpcap.h"
+#endif
+
+#include "ui/simple_dialog.h"
+#include "ui/ws_ui_util.h"
+
+#include "wsutil/file_util.h"
+#include "wsutil/str_util.h"
+#include <wsutil/filesystem.h>
+#include <wsutil/wslog.h>
+#include <wsutil/ws_assert.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;
+    ws_process_id 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_session *cap_session)
+{
+    capture_callback_data_t *cb;
+    GList *cb_item = capture_callbacks;
+
+    /* there should be at least one interested */
+    ws_assert(cb_item != NULL);
+
+    while(cb_item != NULL) {
+        cb = (capture_callback_data_t *)cb_item->data;
+        cb->cb_fct(event, cap_session, 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_new(capture_callback_data_t, 1);
+    cb->cb_fct = func;
+    cb->user_data = user_data;
+
+    capture_callbacks = g_list_prepend(capture_callbacks, cb);
+}
+
+void
+capture_callback_remove(capture_callback_t func, gpointer user_data)
+{
+    capture_callback_data_t *cb;
+    GList *cb_item = capture_callbacks;
+
+    while(cb_item != NULL) {
+        cb = (capture_callback_data_t *)cb_item->data;
+        if(cb->cb_fct == func && cb->user_data == user_data) {
+            capture_callbacks = g_list_remove(capture_callbacks, cb);
+            g_free(cb);
+            return;
+        }
+        cb_item = g_list_next(cb_item);
+    }
+
+    ws_assert_not_reached();
+}
+
+/**
+ * Start a capture.
+ *
+ * @return TRUE if the capture starts successfully, FALSE otherwise.
+ */
+gboolean
+capture_start(capture_options *capture_opts, GPtrArray *capture_comments,
+              capture_session *cap_session, info_data_t* cap_data,
+              void(*update_cb)(void))
+{
+    GString *source;
+
+    cap_session->state = CAPTURE_PREPARING;
+    cap_session->count = 0;
+    ws_message("Capture Start ...");
+    source = get_iface_list_string(capture_opts, IFLIST_SHOW_FILTER);
+    cf_set_tempfile_source((capture_file *)cap_session->cf, source->str);
+    g_string_free(source, TRUE);
+    /* try to start the capture child process */
+    if (!sync_pipe_start(capture_opts, capture_comments, cap_session,
+                         cap_data, update_cb)) {
+        /* We failed to start the capture child. */
+        if(capture_opts->save_file != NULL) {
+            g_free(capture_opts->save_file);
+            capture_opts->save_file = NULL;
+        }
+
+        ws_message("Capture Start failed.");
+        cap_session->state = CAPTURE_STOPPED;
+        return FALSE;
+    }
+
+    // Do we need data structures for ignoring duplicate frames?
+    if (prefs.ignore_dup_frames && capture_opts->real_time_mode) {
+        fifo_string_cache_init(&cap_session->frame_dup_cache,
+                prefs.ignore_dup_frames_cache_entries, g_free);
+        cap_session->frame_cksum = g_checksum_new(G_CHECKSUM_SHA256);
+    }
+
+    /* 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, cap_session);
+
+    wtap_rec_init(&cap_session->rec);
+    ws_buffer_init(&cap_session->buf, 1514);
+
+    cap_session->wtap = NULL;
+
+    if (capture_opts->show_info) {
+        if (cap_data->counts.counts_hash != NULL)
+        {
+            /* Clean up any previous lists of packet counts */
+            g_hash_table_destroy(cap_data->counts.counts_hash);
+        }
+
+        cap_data->counts.counts_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_free);
+        cap_data->counts.other = 0;
+        cap_data->counts.total = 0;
+
+        cap_data->ui.counts = &cap_data->counts;
+
+        capture_info_ui_create(&cap_data->ui, cap_session);
+    }
+
+    return TRUE;
+}
+
+
+void
+capture_stop(capture_session *cap_session)
+{
+    ws_message("Capture Stop ...");
+
+    capture_callback_invoke(capture_cb_capture_stopping, cap_session);
+
+    if (!extcap_session_stop(cap_session)) {
+        extcap_request_stop(cap_session);
+        cap_session->capture_opts->stop_after_extcaps = TRUE;
+    } else {
+        /* stop the capture child gracefully */
+        sync_pipe_stop(cap_session);
+    }
+}
+
+
+void
+capture_kill_child(capture_session *cap_session)
+{
+    ws_info("Capture Kill");
+
+    /* kill the capture child */
+    sync_pipe_kill(cap_session->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_session *cap_session, gboolean is_tempfile,
+                       gboolean drops_known, guint32 drops)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+    int err;
+
+    /* Capture succeeded; attempt to open the capture file. */
+    if (cf_open((capture_file *)cap_session->cf, capture_opts->save_file, WTAP_TYPE_AUTO, 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_file *)cap_session->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_file *)cap_session->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_file *)cap_session->cf, drops);
+    }
+
+    /* read in the packet data */
+    switch (cf_read((capture_file *)cap_session->cf, /*reloading=*/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. */
+            exit_application(0);
+            return FALSE;
+    }
+
+    /* if we didn't capture even a single packet, close the file again */
+    if(cap_session->count == 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"
+                "       " WS_WIKI_URL("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_file *)cap_session->cf)) ? "temporary " : "");
+        cf_close((capture_file *)cap_session->cf);
+    }
+    return TRUE;
+}
+
+static const char *
+cf_open_error_message(int err, gchar *err_info)
+{
+    const char *errmsg;
+    static char errmsg_errno[1024 + 1];
+
+    if (err < 0) {
+        /* Wiretap error. */
+        switch (err) {
+
+        case WTAP_ERR_NOT_REGULAR_FILE:
+            errmsg = "The file \"%s\" is a \"special file\" or socket or other non-regular file.";
+            break;
+
+        case WTAP_ERR_FILE_UNKNOWN_FORMAT:
+            /* Seen only when opening a capture file for reading. */
+            errmsg = "The file \"%s\" isn't a capture file in a format Wireshark understands.";
+            break;
+
+        case WTAP_ERR_UNSUPPORTED:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "The file \"%%s\" contains record data that Wireshark doesn't support.\n"
+                       "(%s)", err_info != NULL ? err_info : "no information supplied");
+            g_free(err_info);
+            errmsg = errmsg_errno;
+            break;
+
+        case WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED:
+            errmsg = "The file \"%s\" is a capture for a network type that Wireshark doesn't support.";
+            break;
+
+        case WTAP_ERR_BAD_FILE:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "The file \"%%s\" appears to be damaged or corrupt.\n"
+                       "(%s)", err_info != NULL ? err_info : "no information supplied");
+            g_free(err_info);
+            errmsg = errmsg_errno;
+            break;
+
+        case WTAP_ERR_CANT_OPEN:
+            errmsg = "The file \"%s\" could not be opened for some unknown reason.";
+            break;
+
+        case WTAP_ERR_SHORT_READ:
+            errmsg = "The file \"%s\" appears to have been cut short"
+                " in the middle of a packet or other data.";
+            break;
+
+        case WTAP_ERR_DECOMPRESS:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "The file \"%%s\" cannot be decompressed; it may be damaged or corrupt.\n"
+                       "(%s)", err_info != NULL ? err_info : "no information supplied");
+            g_free(err_info);
+            errmsg = errmsg_errno;
+            break;
+
+        case WTAP_ERR_INTERNAL:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "An internal error occurred opening the file \"%%s\".\n"
+                       "(%s)", err_info != NULL ? err_info : "no information supplied");
+            g_free(err_info);
+            errmsg = errmsg_errno;
+            break;
+
+        case WTAP_ERR_DECOMPRESSION_NOT_SUPPORTED:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "The file \"%%s\" cannot be decompressed; it is compressed in a way that We don't support.\n"
+                       "(%s)", err_info != NULL ? err_info : "no information supplied");
+            g_free(err_info);
+            errmsg = errmsg_errno;
+            break;
+
+        default:
+            snprintf(errmsg_errno, sizeof(errmsg_errno),
+                       "The file \"%%s\" could not be opened: %s.",
+                       wtap_strerror(err));
+            errmsg = errmsg_errno;
+            break;
+        }
+    }
+    else
+        errmsg = file_open_error_message(err, FALSE);
+    return errmsg;
+}
+
+/* capture child tells us we have a new (or the first) capture file */
+static bool
+capture_input_new_file(capture_session *cap_session, gchar *new_file)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+    gboolean is_tempfile;
+    int  err;
+    gchar *err_info;
+    gchar *err_msg;
+
+    if(cap_session->state == CAPTURE_PREPARING) {
+        ws_message("Capture started");
+    }
+    ws_message("File: \"%s\"", new_file);
+
+    ws_assert(cap_session->state == CAPTURE_PREPARING || cap_session->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*)cap_session->cf)->state == FILE_READ_PENDING) {
+            capture_callback_invoke(capture_cb_capture_fixed_finished, cap_session);
+        } else if (((capture_file*)cap_session->cf)->state != FILE_CLOSED) {
+            cap_session->session_will_restart = TRUE;
+            capture_callback_invoke(capture_cb_capture_update_finished, cap_session);
+            cf_finish_tail((capture_file *)cap_session->cf,
+                           &cap_session->rec, &cap_session->buf, &err,
+                           &cap_session->frame_dup_cache, cap_session->frame_cksum);
+            cf_close((capture_file *)cap_session->cf);
+        }
+        g_free(capture_opts->save_file);
+        is_tempfile = FALSE;
+        cf_set_tempfile((capture_file *)cap_session->cf, FALSE);
+    } else {
+        /* we didn't have a save_file before; must be a tempfile */
+        is_tempfile = TRUE;
+        cf_set_tempfile((capture_file *)cap_session->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_open((capture_file *)cap_session->cf, capture_opts->save_file, WTAP_TYPE_AUTO, 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;
+        }
+    } else {
+        capture_callback_invoke(capture_cb_capture_prepared, cap_session);
+    }
+
+    if(capture_opts->show_info) {
+        if (cap_session->wtap != NULL) {
+            wtap_close(cap_session->wtap);
+        }
+
+        cap_session->wtap = wtap_open_offline(new_file, WTAP_TYPE_AUTO, &err, &err_info, FALSE);
+        if (!cap_session->wtap) {
+            err_msg = ws_strdup_printf(cf_open_error_message(err, err_info),
+                                      new_file);
+            ws_warning("capture_input_new_file: %d (%s)", err, err_msg);
+            g_free(err_msg);
+            return FALSE;
+        }
+    }
+
+    if(capture_opts->real_time_mode) {
+        capture_callback_invoke(capture_cb_capture_update_started, cap_session);
+    } else {
+        capture_callback_invoke(capture_cb_capture_fixed_started, cap_session);
+    }
+    cap_session->state = CAPTURE_RUNNING;
+
+    return TRUE;
+}
+
+static void
+capture_info_packet(info_data_t* cap_info, gint wtap_linktype, const guchar *pd, guint32 caplen, union wtap_pseudo_header *pseudo_header)
+{
+    capture_packet_info_t cpinfo;
+
+    /* Setup the capture packet structure */
+    cpinfo.counts = cap_info->counts.counts_hash;
+
+    cap_info->counts.total++;
+    if (!try_capture_dissector("wtap_encap", wtap_linktype, pd, 0, caplen, &cpinfo, pseudo_header))
+        cap_info->counts.other++;
+}
+
+/* new packets arrived */
+static void
+capture_info_new_packets(int to_read, wtap *wth, info_data_t* cap_info)
+{
+    int err;
+    gchar *err_info;
+    gint64 data_offset;
+    wtap_rec rec;
+    Buffer buf;
+    union wtap_pseudo_header *pseudo_header;
+    int wtap_linktype;
+
+    cap_info->ui.new_packets = to_read;
+
+    /*ws_warning("new packets: %u", to_read);*/
+
+    wtap_rec_init(&rec);
+    ws_buffer_init(&buf, 1514);
+    while (to_read > 0) {
+        wtap_cleareof(wth);
+        if (wtap_read(wth, &rec, &buf, &err, &err_info, &data_offset)) {
+            if (rec.rec_type == REC_TYPE_PACKET) {
+                pseudo_header = &rec.rec_header.packet_header.pseudo_header;
+                wtap_linktype = rec.rec_header.packet_header.pkt_encap;
+
+                capture_info_packet(cap_info, wtap_linktype,
+                    ws_buffer_start_ptr(&buf),
+                    rec.rec_header.packet_header.caplen,
+                    pseudo_header);
+
+                /*ws_warning("new packet");*/
+                to_read--;
+            }
+            wtap_rec_reset(&rec);
+        }
+    }
+    wtap_rec_cleanup(&rec);
+    ws_buffer_free(&buf);
+
+    capture_info_ui_update(&cap_info->ui);
+}
+
+/* capture child tells us we have new packets to read */
+static void
+capture_input_new_packets(capture_session *cap_session, int to_read)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+    int  err;
+
+    ws_assert(capture_opts->save_file);
+
+    if(capture_opts->real_time_mode) {
+        if (((capture_file*)cap_session->cf)->state == FILE_READ_PENDING) {
+            /* Attempt to open the capture file and set up to read from it. */
+            switch (cf_open((capture_file*)cap_session->cf, capture_opts->save_file, WTAP_TYPE_AUTO, cf_is_tempfile((capture_file*)cap_session->cf), &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;
+                capture_kill_child(cap_session);
+            }
+            capture_callback_invoke(capture_cb_capture_update_started, cap_session);
+        }
+        /* Read from the capture file the number of records the child told us it added. */
+        to_read += cap_session->count_pending;
+        cap_session->count_pending = 0;
+        switch (cf_continue_tail((capture_file *)cap_session->cf, to_read,
+                                 &cap_session->rec, &cap_session->buf, &err,
+                                 &cap_session->frame_dup_cache, cap_session->frame_cksum)) {
+
+            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, cap_session);
+                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(cap_session);
+                break;
+        }
+    } else {
+        cf_fake_continue_tail((capture_file *)cap_session->cf);
+        cap_session->count_pending += to_read;
+
+        capture_callback_invoke(capture_cb_capture_fixed_continue, cap_session);
+    }
+
+    if(cap_session->wtap)
+        capture_info_new_packets(to_read, cap_session->wtap, cap_session->cap_data_info);
+}
+
+
+/* Capture child told us how many dropped packets it counted.
+ */
+static void
+capture_input_drops(capture_session *cap_session, guint32 dropped, const char* interface_name)
+{
+    if (interface_name != NULL) {
+        ws_info("%u packet%s dropped from %s", dropped, plurality(dropped, "", "s"), interface_name);
+    } else {
+        ws_info("%u packet%s dropped", dropped, plurality(dropped, "", "s"));
+    }
+
+    ws_assert(cap_session->state == CAPTURE_RUNNING);
+
+    cf_set_drops_known((capture_file *)cap_session->cf, TRUE);
+    cf_set_drops((capture_file *)cap_session->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.
+ */
+static void
+capture_input_error(capture_session *cap_session _U_, char *error_msg,
+                    char *secondary_error_msg)
+{
+    gchar *safe_error_msg;
+    gchar *safe_secondary_error_msg;
+
+    ws_message("Error message from child: \"%s\", \"%s\"", error_msg, secondary_error_msg);
+
+    ws_assert(cap_session->state == CAPTURE_PREPARING || cap_session->state == CAPTURE_RUNNING);
+
+    safe_error_msg = simple_dialog_format_message(error_msg);
+    if (secondary_error_msg != NULL && *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.
+ */
+static void
+capture_input_cfilter_error(capture_session *cap_session, guint i,
+                            const char *error_message)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+    dfilter_t *rfcode = NULL;
+    gchar *safe_cfilter;
+    gchar *safe_descr;
+    gchar *safe_cfilter_error_msg;
+    interface_options *interface_opts;
+
+    ws_message("Capture filter error message from child: \"%s\"", error_message);
+
+    ws_assert(cap_session->state == CAPTURE_PREPARING || cap_session->state == CAPTURE_RUNNING);
+    ws_assert(i < capture_opts->ifaces->len);
+
+    interface_opts = &g_array_index(capture_opts->ifaces, interface_options, i);
+    safe_cfilter = simple_dialog_format_message(interface_opts->cfilter);
+    safe_descr = simple_dialog_format_message(interface_opts->descr);
+    safe_cfilter_error_msg = simple_dialog_format_message(error_message);
+    /* Did the user try a display filter? */
+    if (dfilter_compile(interface_opts->cfilter, &rfcode, NULL) && rfcode != NULL) {
+        simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
+                "%sInvalid capture filter \"%s\" for interface %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, safe_descr,
+                simple_dialog_primary_end(), safe_cfilter_error_msg);
+        dfilter_free(rfcode);
+    } else {
+        simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
+                "%sInvalid capture filter \"%s\" for interface %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, safe_descr,
+                simple_dialog_primary_end(), safe_cfilter_error_msg);
+    }
+    g_free(safe_cfilter_error_msg);
+    g_free(safe_descr);
+    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 */
+static void
+capture_input_closed(capture_session *cap_session, gchar *msg)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+    int  err;
+
+    ws_message("Capture stopped.");
+    ws_assert(cap_session->state == CAPTURE_PREPARING || cap_session->state == CAPTURE_RUNNING);
+
+    if (msg != NULL) {
+        ESD_TYPE_E dlg_type = ESD_TYPE_ERROR;
+        if (strstr(msg, " WARNING] ")) {
+            dlg_type = ESD_TYPE_WARN;
+        }
+        /*
+         * ws_log prefixes log messages with a timestamp delimited by " -- " and possibly
+         * a function name delimited by "(): ". Log it to sterr, but omit it in the UI.
+         */
+        char *plain_msg = strstr(msg, "(): ");
+        if (plain_msg != NULL) {
+            plain_msg += strlen("(): ");
+        } else if ((plain_msg = strstr(msg, " -- ")) != NULL) {
+            plain_msg += strlen(" -- ");
+        } else {
+            plain_msg = msg;
+        }
+        ws_warning("%s", msg);
+        simple_dialog(dlg_type, ESD_BTN_OK, "%s", plain_msg);
+    }
+
+    wtap_rec_cleanup(&cap_session->rec);
+    ws_buffer_free(&cap_session->buf);
+    if(cap_session->state == CAPTURE_PREPARING) {
+        /* We started the capture child, but we didn't manage to start
+           the capture process; note that the attempt to start it
+           failed. */
+        capture_callback_invoke(capture_cb_capture_failed, cap_session);
+    } else {
+        /* We started a capture; process what's left of the capture file if
+           we were in "update list of packets in real time" mode, or process
+           all of it if we weren't. */
+        if(((capture_file*)cap_session->cf)->state == FILE_READ_IN_PROGRESS) {
+            cf_read_status_t status;
+
+            /* Read what remains of the capture file. */
+            status = cf_finish_tail((capture_file *)cap_session->cf,
+                                    &cap_session->rec, &cap_session->buf, &err,
+                                    &cap_session->frame_dup_cache, cap_session->frame_cksum);
+
+            // The real-time reading of the pcap is done. Now we can clear the
+            // dup-frame cache, if present. But check that we actually have
+            // data structures to clear (by checking frame-checksum); the user
+            // could have changed the preference *during* the live capture.
+            if (cap_session->frame_cksum != NULL) {
+                fifo_string_cache_free(&cap_session->frame_dup_cache);
+                g_checksum_free(cap_session->frame_cksum);
+                cap_session->frame_cksum = NULL;
+            }
+
+            /* 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 */
+            cap_session->session_will_restart = FALSE;
+            capture_callback_invoke(capture_cb_capture_update_finished, cap_session);
+
+            /* Finish the capture. */
+            switch (status) {
+
+                case CF_READ_OK:
+                    if (cap_session->count == 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"
+                                "       " WS_WIKI_URL("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_file *)cap_session->cf) ? "temporary " : "");
+                        cf_close((capture_file *)cap_session->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. */
+                    exit_application(0);
+                    break;
+            }
+        } else if (((capture_file*)cap_session->cf)->state == FILE_READ_PENDING) {
+            /* first of all, we are not doing a capture any more */
+            capture_callback_invoke(capture_cb_capture_fixed_finished, cap_session);
+
+            /* 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(cap_session, cf_is_tempfile((capture_file *)cap_session->cf),
+                        cf_get_drops_known((capture_file *)cap_session->cf), cf_get_drops((capture_file *)cap_session->cf));
+            }
+        }
+    }
+
+    capture_info_ui_destroy(&cap_session->cap_data_info->ui);
+    if(cap_session->wtap) {
+        wtap_close(cap_session->wtap);
+        cap_session->wtap = NULL;
+    }
+
+    cap_session->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_file *)cap_session->cf);
+        return;
+    }
+
+    /* does the user wants to restart the current capture? */
+    if(capture_opts->restart) {
+        capture_opts->restart = FALSE;
+
+        /* If we have a ring buffer, the original save file has been overwritten
+           with the "ring filename".  Restore it before starting again */
+        if ((capture_opts->multi_files_on) && (capture_opts->orig_save_file != NULL)) {
+            g_free(capture_opts->save_file);
+            capture_opts->save_file = g_strdup(capture_opts->orig_save_file);
+        }
+
+        /* If it was a tempfile, throw away the old filename (so it will become a tempfile again) */
+        if (cf_is_tempfile((capture_file *)cap_session->cf)) {
+            g_free(capture_opts->save_file);
+            capture_opts->save_file = NULL;
+        }
+    } 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(capture_options *capture_opts)
+{
+    int stat_fd;
+    ws_process_id fork_child;
+    gchar *msg;
+    if_stat_cache_t *sc = g_new0(if_stat_cache_t, 1);
+    if_stat_cache_item_t *sc_item;
+    guint i;
+    interface_t *device;
+
+    sc->stat_fd = -1;
+    sc->fork_child = WS_INVALID_PID;
+
+    /* 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, NULL) == 0) {
+        sc->stat_fd = stat_fd;
+        sc->fork_child = fork_child;
+
+        /* Initialize the cache */
+        for (i = 0; i < capture_opts->all_ifaces->len; i++) {
+            device = &g_array_index(capture_opts->all_ifaces, interface_t, i);
+            if (device->type != IF_PIPE && device->type != IF_EXTCAP) {
+                sc_item = g_new0(if_stat_cache_item_t, 1);
+                ws_assert(device->if_info.name);
+                sc_item->name = g_strdup(device->if_info.name);
+                sc->cache_list = g_list_prepend(sc->cache_list, sc_item);
+            }
+        }
+    } else {
+        ws_warning("%s", msg);
+        g_free(msg); /* XXX: should we display this to the user via the GUI? */
+    }
+    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 || sc->fork_child == WS_INVALID_PID) {
+        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 = (if_stat_cache_item_t *)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 || sc->fork_child == WS_INVALID_PID || !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 = (if_stat_cache_item_t *)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;
+    int ret;
+    gchar *msg;
+
+    if (!sc) {
+        return;
+    }
+
+    if (sc->fork_child != WS_INVALID_PID) {
+        ret = sync_interface_stats_close(&sc->stat_fd, &sc->fork_child, &msg);
+        if (ret == -1) {
+            /* XXX - report failure? */
+            g_free(msg);
+        }
+    }
+
+    for (sc_entry = sc->cache_list; sc_entry != NULL; sc_entry = g_list_next(sc_entry)) {
+        sc_item = (if_stat_cache_item_t *)sc_entry->data;
+        g_free(sc_item->name);
+        g_free(sc_item);
+    }
+    g_list_free(sc->cache_list);
+    g_free(sc);
+}
+
+/* Initialize a capture session for our callbacks. */
+void
+capture_input_init(capture_session *cap_session, capture_file *cf)
+{
+    capture_session_init(cap_session, cf,
+                         capture_input_new_file, capture_input_new_packets,
+                         capture_input_drops, capture_input_error,
+                         capture_input_cfilter_error, capture_input_closed);
+}
+#endif /* HAVE_LIBPCAP */