Move capture.[ch] to libui.

Change-Id: I86e7e781cc9e14abab0374a18b95438529b046f0
Reviewed-on: https://code.wireshark.org/review/2711
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 799 insertions, 0 deletions

diff --git a/ui/capture.c b/ui/capture.c
new file mode 100644
index 0000000000..9665bcb340
--- /dev/null
+++ b/ui/capture.c
@@ -0,0 +1,799 @@
+/* capture.c
+ * Routines for packet capture
+ *
+ * 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"
+
+#ifdef HAVE_LIBPCAP
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/dfilter/dfilter.h>
+#include "file.h"
+#include "ui/capture.h"
+#include <capchild/capture_ifinfo.h>
+#include <capchild/capture_sync.h>
+#include "capture_info.h"
+#include "ui/capture_ui_utils.h"
+#include "ui/util.h"
+#include "capture-pcap-util.h"
+#include <epan/prefs.h>
+
+#ifdef _WIN32
+#include "capture-wpcap.h"
+#endif
+
+#include "ui/simple_dialog.h"
+#include "ui/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_session *cap_session)
+{
+  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 = (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 = (capture_callback_data_t *)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 = (capture_callback_data_t *)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, capture_session *cap_session, void(*update_cb)(void))
+{
+  gboolean ret;
+  guint i;
+  GString *source = g_string_new("");
+
+  cap_session->state = CAPTURE_PREPARING;
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Start ...");
+#ifdef _WIN32
+  if (capture_opts->ifaces->len < 2) {
+#else
+  if (capture_opts->ifaces->len < 4) {
+#endif
+    for (i = 0; i < capture_opts->ifaces->len; i++) {
+      interface_options interface_opts;
+
+      interface_opts = g_array_index(capture_opts->ifaces, interface_options, i);
+      if (i > 0) {
+          if (capture_opts->ifaces->len > 2) {
+              g_string_append_printf(source, ",");
+          }
+          g_string_append_printf(source, " ");
+          if (i == capture_opts->ifaces->len - 1) {
+              g_string_append_printf(source, "and ");
+          }
+      }
+      g_string_append_printf(source, "%s", get_iface_description_for_interface(capture_opts, i));
+      if ((interface_opts.cfilter != NULL) &&
+          (strlen(interface_opts.cfilter) > 0)) {
+        g_string_append_printf(source, " (%s)", interface_opts.cfilter);
+      }
+    }
+  } else {
+    g_string_append_printf(source, "%u interfaces", capture_opts->ifaces->len);
+  }
+  cf_set_tempfile_source((capture_file *)cap_session->cf, source->str);
+  g_string_free(source, TRUE);
+  /* try to start the capture child process */
+  ret = sync_pipe_start(capture_opts, cap_session, update_cb);
+  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!");
+      cap_session->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, cap_session);
+
+      if(capture_opts->show_info)
+        capture_info_open(cap_session);
+  }
+
+  return ret;
+}
+
+
+void
+capture_stop(capture_session *cap_session)
+{
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Stop ...");
+
+  capture_callback_invoke(capture_cb_capture_stopping, cap_session);
+
+  /* stop the capture child gracefully */
+  sync_pipe_stop(cap_session);
+}
+
+
+void
+capture_restart(capture_session *cap_session)
+{
+    capture_options *capture_opts = cap_session->capture_opts;
+
+    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Restart");
+
+    capture_opts->restart = TRUE;
+    capture_stop(cap_session);
+}
+
+
+void
+capture_kill_child(capture_session *cap_session)
+{
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_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, 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_file *)cap_session->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_file *)cap_session->cf)) ? "temporary " : "");
+    cf_close((capture_file *)cap_session->cf);
+  }
+  return TRUE;
+}
+
+
+/* capture child tells us we have a new (or the first) capture file */
+gboolean
+capture_input_new_file(capture_session *cap_session, gchar *new_file)
+{
+  capture_options *capture_opts = cap_session->capture_opts;
+  gboolean is_tempfile;
+  int  err;
+
+  if(cap_session->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(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_CLOSED) {
+        if(capture_opts->real_time_mode) {
+            capture_callback_invoke(capture_cb_capture_update_finished, cap_session);
+            cf_finish_tail((capture_file *)cap_session->cf, &err);
+            cf_close((capture_file *)cap_session->cf);
+        } else {
+            capture_callback_invoke(capture_cb_capture_fixed_finished, cap_session);
+        }
+    }
+    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 (!capture_info_new_file(new_file))
+      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;
+}
+
+
+/* capture child tells us we have new packets to read */
+void
+capture_input_new_packets(capture_session *cap_session, int to_read)
+{
+  capture_options *capture_opts = cap_session->capture_opts;
+  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_file *)cap_session->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, 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 {
+    /* increase the capture file packet counter by the number of incoming packets */
+    cf_set_packet_count((capture_file *)cap_session->cf,
+        cf_get_packet_count((capture_file *)cap_session->cf) + to_read);
+    cf_fake_continue_tail((capture_file *)cap_session->cf);
+
+    capture_callback_invoke(capture_cb_capture_fixed_continue, cap_session);
+  }
+
+  /* update the main window so we get events (e.g. from the stop toolbar button) */
+  /* This causes a hang on Windows (see bug 7305). Do we need this on any platform? */
+#ifndef _WIN32
+  main_window_update();
+#endif
+
+  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_session *cap_session, guint32 dropped)
+{
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_INFO, "%u packet%s dropped", dropped, plurality(dropped, "", "s"));
+
+  g_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.
+ */
+void
+capture_input_error_message(capture_session *cap_session, 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(cap_session->state == CAPTURE_PREPARING || cap_session->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_session *cap_session, guint i,
+                                    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;
+
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture filter error message from child: \"%s\"", error_message);
+
+  g_assert(cap_session->state == CAPTURE_PREPARING || cap_session->state == CAPTURE_RUNNING);
+  g_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) && 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 */
+void
+capture_input_closed(capture_session *cap_session, gchar *msg)
+{
+  capture_options *capture_opts = cap_session->capture_opts;
+  int  err;
+  int  packet_count_save;
+
+  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture stopped!");
+  g_assert(cap_session->state == CAPTURE_PREPARING || cap_session->state == CAPTURE_RUNNING);
+
+  if (msg != NULL)
+    simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", msg);
+
+  if(cap_session->state == CAPTURE_PREPARING) {
+    /* We didn't start a capture; 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_opts->real_time_mode) {
+      cf_read_status_t status;
+
+      /* Read what remains of the capture file. */
+      status = cf_finish_tail((capture_file *)cap_session->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_file *)cap_session->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, cap_session);
+
+      /* 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_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. */
+        main_window_quit();
+        break;
+      }
+    } else {
+      /* 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));
+      }
+    }
+  }
+
+  if(capture_opts->show_info)
+    capture_info_close();
+
+  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;
+
+    ws_unlink(capture_opts->save_file);
+
+    /* 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;
+    }
+
+    /* ... and start the capture again */
+    if (capture_opts->ifaces->len == 0) {
+      collect_ifaces(capture_opts);
+    }
+
+    /* close the currently loaded capture file */
+    cf_close((capture_file *)cap_session->cf);
+
+    capture_start(capture_opts, cap_session,NULL); /*XXX is this NULL ok or we need an update_cb???*/
+  } 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, fork_child;
+  gchar *msg;
+  if_stat_cache_t *sc = NULL;
+  if_stat_cache_item_t *sc_item;
+  guint i;
+  interface_t device;
+
+  /* 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 = (if_stat_cache_t *)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 (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) {
+        sc_item = (if_stat_cache_item_t *)g_malloc0(sizeof(if_stat_cache_item_t));
+        sc_item->name = g_strdup(device.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 = (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 || !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;
+
+  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_free(sc);
+}
+
+#endif /* HAVE_LIBPCAP */