Allow bigger snapshot lengths for D-Bus captures.

Use WTAP_MAX_PACKET_SIZE_STANDARD, set to 256KB, for everything except
for D-Bus captures.  Use WTAP_MAX_PACKET_SIZE_DBUS, set to 128MB, for
them, because that's the largest possible D-Bus message size.  See

	https://bugs.freedesktop.org/show_bug.cgi?id=100220

for an example of the problems caused by limiting the snapshot length to
256KB for D-Bus.

Have a snapshot length of 0 in a capture_file structure mean "there is
no snapshot length for the file"; we don't need the has_snap field in
that case, a value of 0 mean "no, we don't have a snapshot length".

In dumpcap, start out with a pipe buffer size of 2KB, and grow it as
necessary.  When checking for a too-big packet from a pipe, check
against the appropriate maximum - 128MB for DLT_DBUS, 256KB for
everything else.

Change-Id: Ib2ce7a0cf37b971fbc0318024fd011e18add8b20
Reviewed-on: https://code.wireshark.org/review/21952
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Guy Harris <guy@alum.mit.edu>

16 files changed, 45 insertions, 41 deletions

diff --git a/ui/capture_ui_utils.c b/ui/capture_ui_utils.c
index 36e75b37e9..5655632d91 100644
--- a/ui/capture_ui_utils.c
+++ b/ui/capture_ui_utils.c
@@ -202,10 +202,10 @@ capture_dev_user_snaplen_find(const gchar *if_name, gboolean *hassnap, int *snap
     if (strcmp(if_tokens[i], if_name) == 0) {
       /* OK, this matches. */
       if (*(colonp + 1) == '0') {
-        /* {hassnap} is false, so just set the snaplen to WTAP_MAX_PACKET_SIZE. */
+        /* {hassnap} is false, so just set the snaplen to WTAP_MAX_PACKET_SIZE_STANDARD. */
         found = TRUE;
         *hassnap = FALSE;
-        *snaplen = WTAP_MAX_PACKET_SIZE;
+        *snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
       } else if (*(colonp + 1) == '1') {
         /* {hassnap} is true, so extract {snaplen} */
         if (*(colonp + 2) != '(') {
diff --git a/ui/commandline.c b/ui/commandline.c
index fc4be16010..b7c1ef7db4 100644
--- a/ui/commandline.c
+++ b/ui/commandline.c
@@ -93,7 +93,11 @@ commandline_print_usage(gboolean for_help_option) {
     fprintf(output, "Capture interface:\n");
     fprintf(output, "  -i <interface>           name or idx of interface (def: first non-loopback)\n");
     fprintf(output, "  -f <capture filter>      packet filter in libpcap filter syntax\n");
-    fprintf(output, "  -s <snaplen>             packet snapshot length (def: %u)\n", WTAP_MAX_PACKET_SIZE);
+#ifdef HAVE_PCAP_CREATE
+    fprintf(output, "  -s <snaplen>             packet snapshot length (def: appropriate maximum)\n");
+#else
+    fprintf(output, "  -s <snaplen>             packet snapshot length (def: %u)\n", WTAP_MAX_PACKET_SIZE_STANDARD);
+#endif
     fprintf(output, "  -p                       don't capture in promiscuous mode\n");
     fprintf(output, "  -k                       start capturing immediately (def: do nothing)\n");
     fprintf(output, "  -S                       update packet display when new packets are captured\n");
diff --git a/ui/gtk/capture_dlg.c b/ui/gtk/capture_dlg.c
index 870d0e1623..719bcc81b9 100644
--- a/ui/gtk/capture_dlg.c
+++ b/ui/gtk/capture_dlg.c
@@ -2476,7 +2476,7 @@ save_options_cb(GtkWidget *win _U_, gpointer user_data _U_)
     if (device.snaplen < MIN_PACKET_SIZE)
       device.snaplen = MIN_PACKET_SIZE;
   } else {
-    device.snaplen = WTAP_MAX_PACKET_SIZE;
+    device.snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
   }
   filter_text = gtk_combo_box_text_get_active_text(GTK_COMBO_BOX_TEXT(filter_cm));
   if (device.cfilter)
@@ -2527,8 +2527,8 @@ adjust_snap_sensitivity(GtkWidget *tb _U_, gpointer parent_w _U_)
       gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(snap_cb)));
   device.has_snaplen = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(snap_cb));
   if (!device.has_snaplen) {
-    gtk_spin_button_set_value(GTK_SPIN_BUTTON (snap_sb), WTAP_MAX_PACKET_SIZE);
-    device.snaplen = WTAP_MAX_PACKET_SIZE;
+    gtk_spin_button_set_value(GTK_SPIN_BUTTON (snap_sb), WTAP_MAX_PACKET_SIZE_STANDARD);
+    device.snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
   }
   g_array_insert_val(global_capture_opts.all_ifaces, marked_interface, device);
 }
@@ -2654,7 +2654,7 @@ void options_interface_cb(GtkTreeView *view, GtkTreePath *path, GtkTreeViewColum
   device.monitor_mode_supported = FALSE;
 #endif
   device.has_snaplen = FALSE;
-  device.snaplen = WTAP_MAX_PACKET_SIZE;
+  device.snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
   device.cfilter = NULL;
 #ifdef CAN_SET_CAPTURE_BUFFER_SIZE
   device.buffer = DEFAULT_CAPTURE_BUFFER_SIZE;
@@ -2897,7 +2897,7 @@ void options_interface_cb(GtkTreeView *view, GtkTreePath *path, GtkTreeViewColum
   gtk_box_pack_start(GTK_BOX(snap_hb), snap_cb, FALSE, FALSE, 0);
 
   snap_adj = (GtkAdjustment *) gtk_adjustment_new((gfloat) device.snaplen,
-    MIN_PACKET_SIZE, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+    MIN_PACKET_SIZE, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
   snap_sb = gtk_spin_button_new (snap_adj, 0, 0);
   gtk_spin_button_set_wrap (GTK_SPIN_BUTTON (snap_sb), TRUE);
   gtk_widget_set_size_request(snap_sb, 80, -1);
@@ -2979,7 +2979,7 @@ void options_interface_cb(GtkTreeView *view, GtkTreePath *path, GtkTreeViewColum
   gtk_box_pack_start (GTK_BOX(buffer_size_hb), buffer_size_lb, FALSE, FALSE, 0);
 
   buffer_size_adj = (GtkAdjustment *) gtk_adjustment_new((gfloat) device.buffer,
-    1, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+    1, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
   buffer_size_sb = gtk_spin_button_new (buffer_size_adj, 0, 0);
   gtk_spin_button_set_value(GTK_SPIN_BUTTON (buffer_size_sb), (gfloat) device.buffer);
   gtk_spin_button_set_wrap (GTK_SPIN_BUTTON (buffer_size_sb), TRUE);
@@ -5752,7 +5752,7 @@ create_and_fill_model(GtkTreeView *view)
         device.has_snaplen = hassnap;
       } else {
         /* No preferences set yet, use default values */
-        device.snaplen = WTAP_MAX_PACKET_SIZE;
+        device.snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
         device.has_snaplen = FALSE;
       }
 
diff --git a/ui/gtk/file_import_dlg.c b/ui/gtk/file_import_dlg.c
index 0076fe9bde..b5745a6d7e 100644
--- a/ui/gtk/file_import_dlg.c
+++ b/ui/gtk/file_import_dlg.c
@@ -501,7 +501,7 @@ file_import_open(text_import_info_t *info)
     int_data_mand = (wtapng_if_descr_mandatory_t*)wtap_block_get_mandatory_data(int_data);
     int_data_mand->wtap_encap            = info->encapsulation;
     int_data_mand->time_units_per_second = 1000000; /* default microsecond resolution */
-    int_data_mand->snap_len              = WTAP_MAX_PACKET_SIZE;
+    int_data_mand->snap_len              = WTAP_MAX_PACKET_SIZE_STANDARD;
     wtap_block_add_string_option(int_data, OPT_IDB_NAME, "Fake IF File->Import", strlen("Fake IF File->Import"));
 
     g_array_append_val(idb_inf->interface_data, int_data);
@@ -1155,7 +1155,7 @@ file_import_dlg_new(void)
 
     framelen_te = gtk_entry_new();
     maxsize_msg = g_strdup_printf("The maximum size of the frames to write to the import capture file (max %u)",
-                                  WTAP_MAX_PACKET_SIZE);
+                                  WTAP_MAX_PACKET_SIZE_STANDARD);
     gtk_widget_set_tooltip_text(framelen_te, maxsize_msg);
     g_free(maxsize_msg);
     gtk_box_pack_start(GTK_BOX(framelen_hb), framelen_te, FALSE, FALSE, 0);
diff --git a/ui/gtk/gsm_map_summary.c b/ui/gtk/gsm_map_summary.c
index 15fd6b9644..e3dcd57d7b 100644
--- a/ui/gtk/gsm_map_summary.c
+++ b/ui/gtk/gsm_map_summary.c
@@ -128,7 +128,7 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   g_snprintf(string_buff, SUM_STR_MAX, "Format: %s", wtap_file_type_subtype_string(summary.file_type));
   add_string_to_box(string_buff, file_box);
 
-  if (summary.has_snap) {
+  if (summary.snap != 0) {
     /* snapshot length */
     g_snprintf(string_buff, SUM_STR_MAX, "Snapshot length: %u", summary.snap);
     add_string_to_box(string_buff, file_box);
diff --git a/ui/gtk/mtp3_summary.c b/ui/gtk/mtp3_summary.c
index 1917720449..7e2d4c93c3 100644
--- a/ui/gtk/mtp3_summary.c
+++ b/ui/gtk/mtp3_summary.c
@@ -339,7 +339,7 @@ mtp3_sum_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
     g_snprintf(string_buff, SUM_STR_MAX, "Format: %s", (file_type ? file_type : "N/A"));
     add_string_to_box(string_buff, file_box);
 
-    if (summary.has_snap) {
+    if (summary.snap != 0) {
         /* snapshot length */
         g_snprintf(string_buff, SUM_STR_MAX, "Snapshot length: %u", summary.snap);
         add_string_to_box(string_buff, file_box);
diff --git a/ui/gtk/prefs_capture.c b/ui/gtk/prefs_capture.c
index d12499726c..ff716c083b 100644
--- a/ui/gtk/prefs_capture.c
+++ b/ui/gtk/prefs_capture.c
@@ -677,7 +677,7 @@ ifopts_edit_cb(GtkWidget *w, gpointer data _U_)
 
 #ifdef CAN_SET_CAPTURE_BUFFER_SIZE
 	renderer = gtk_cell_renderer_spin_new ();
-	buffer_size_adj = (GtkAdjustment *) gtk_adjustment_new(DEFAULT_CAPTURE_BUFFER_SIZE, 1, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+	buffer_size_adj = (GtkAdjustment *) gtk_adjustment_new(DEFAULT_CAPTURE_BUFFER_SIZE, 1, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
 	g_object_set(G_OBJECT(renderer), "adjustment", buffer_size_adj, NULL);
 	column = gtk_tree_view_column_new_with_attributes ("Default buffer size (MiB)", renderer,
 							   "text", BUF_COLUMN,
@@ -695,7 +695,7 @@ ifopts_edit_cb(GtkWidget *w, gpointer data _U_)
 	gtk_tree_view_column_set_resizable(column, FALSE);
 	/*gtk_tree_view_column_set_sizing(column, GTK_TREE_VIEW_COLUMN_FIXED);*/
 	renderer = gtk_cell_renderer_spin_new ();
-	snaplen_adj = (GtkAdjustment *) gtk_adjustment_new(WTAP_MAX_PACKET_SIZE, 1, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+	snaplen_adj = (GtkAdjustment *) gtk_adjustment_new(WTAP_MAX_PACKET_SIZE_STANDARD, 1, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
 	g_object_set(G_OBJECT(renderer), "adjustment", snaplen_adj, NULL);
 	column = gtk_tree_view_column_new_with_attributes ("Default snap length", renderer,
 							   "text", SNAPLEN_COLUMN,
@@ -834,7 +834,7 @@ ifopts_edit_cb(GtkWidget *w, gpointer data _U_)
 	ws_gtk_grid_attach_defaults(GTK_GRID(main_grid), if_buffersize_lb, 0, row, 1, 1);
 	gtk_misc_set_alignment(GTK_MISC(if_buffersize_lb), 1.0f, 0.5f);
 	gtk_widget_show(if_buffersize_lb);
-	buffer_size_adj = (GtkAdjustment *) gtk_adjustment_new(DEFAULT_CAPTURE_BUFFER_SIZE, 1, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+	buffer_size_adj = (GtkAdjustment *) gtk_adjustment_new(DEFAULT_CAPTURE_BUFFER_SIZE, 1, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
 	if_buffersize_cb = gtk_spin_button_new (buffer_size_adj, 0, 0);
 	g_signal_connect(if_buffersize_cb, "value-changed", G_CALLBACK(ifopts_edit_buffersize_changed_cb),
 			cur_list);
@@ -852,7 +852,7 @@ ifopts_edit_cb(GtkWidget *w, gpointer data _U_)
 			cur_list);
 	ws_gtk_grid_attach_defaults(GTK_GRID(main_grid), if_snaplen_tg, 2, row, 1, 1);
 	gtk_widget_show(if_snaplen_tg);
-	snaplen_adj = (GtkAdjustment *) gtk_adjustment_new(WTAP_MAX_PACKET_SIZE, 1, WTAP_MAX_PACKET_SIZE, 1.0, 10.0, 0.0);
+	snaplen_adj = (GtkAdjustment *) gtk_adjustment_new(WTAP_MAX_PACKET_SIZE_STANDARD, 1, WTAP_MAX_PACKET_SIZE_STANDARD, 1.0, 10.0, 0.0);
 	if_snaplen_cb = gtk_spin_button_new (snaplen_adj, 0, 0);
 	g_signal_connect(if_snaplen_cb, "value-changed", G_CALLBACK(ifopts_edit_snaplen_changed_cb),
 			cur_list);
@@ -1449,7 +1449,7 @@ ifopts_edit_snaplen_changed_cb(GtkSpinButton *sb _U_, gpointer udata _U_)
 
 	/* get current description text and set value in list_store for currently selected interface */
 	snaplen = gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(sb));
-	if (snaplen != WTAP_MAX_PACKET_SIZE) {
+	if (snaplen != WTAP_MAX_PACKET_SIZE_STANDARD) {
 		hassnap = TRUE;
 	} else {
 		hassnap = FALSE;
@@ -1656,7 +1656,7 @@ ifopts_options_add(GtkListStore *list_store, if_info_t *if_info)
 #endif
 
         if (!capture_dev_user_snaplen_find(if_info->name, &hassnap, &snaplen)) {
-		snaplen = WTAP_MAX_PACKET_SIZE;
+		snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
 		hassnap = FALSE;
 	}
 
@@ -2007,7 +2007,7 @@ ifopts_write_new_snaplen(void)
 			 * create/cat interface snap length to new string
 			 * (leave space for parens, comma and terminator)
 			 */
-			tmp_snaplen = g_strdup_printf("%s:%d(%d)", ifnm, hassnap, (hassnap?snaplen:WTAP_MAX_PACKET_SIZE));
+			tmp_snaplen = g_strdup_printf("%s:%d(%d)", ifnm, hassnap, (hassnap?snaplen:WTAP_MAX_PACKET_SIZE_STANDARD));
 			g_strlcat(new_snaplen, tmp_snaplen, MAX_VAL_LEN);
 			g_free(tmp_snaplen);
 			g_free(ifnm);
diff --git a/ui/gtk/summary_dlg.c b/ui/gtk/summary_dlg.c
index 41946ca9ea..e219f6648f 100644
--- a/ui/gtk/summary_dlg.c
+++ b/ui/gtk/summary_dlg.c
@@ -268,7 +268,7 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
     g_snprintf(string_buff, SUM_STR_MAX, "%s", wtap_encap_string(summary.file_encap_type));
     add_string_to_grid(grid, &row, "Encapsulation:", string_buff);
   }
-  if (summary.has_snap) {
+  if (summary.snap != 0) {
     /* snapshot length */
     g_snprintf(string_buff, SUM_STR_MAX, "%u bytes", summary.snap);
     add_string_to_grid(grid, &row, "Packet size limit:", string_buff);
@@ -708,7 +708,7 @@ summary_to_texbuff(GtkTextBuffer *buffer)
     g_snprintf(string_buff, SUM_STR_MAX, INDENT "Encapsulation: %s\n", wtap_encap_string(summary.file_encap_type));
     gtk_text_buffer_insert_at_cursor (buffer, string_buff, -1);
   }
-  if (summary.has_snap) {
+  if (summary.snap != 0) {
     /* snapshot length */
     g_snprintf(string_buff, SUM_STR_MAX, INDENT "Packet size limit: %u bytes\n", summary.snap);
     gtk_text_buffer_insert_at_cursor (buffer, string_buff, -1);
diff --git a/ui/qt/capture_file_properties_dialog.cpp b/ui/qt/capture_file_properties_dialog.cpp
index 0cf0404fd0..dd53edfd32 100644
--- a/ui/qt/capture_file_properties_dialog.cpp
+++ b/ui/qt/capture_file_properties_dialog.cpp
@@ -192,7 +192,7 @@ QString CaptureFilePropertiesDialog::summaryToHtml()
         << table_data_tmpl.arg(encaps_str)
         << table_row_end;
 
-    if (summary.has_snap) {
+    if (summary.snap != 0) {
         out << table_row_begin
             << table_vheader_tmpl.arg(tr("Snapshot length"))
             << table_data_tmpl.arg(summary.snap)
diff --git a/ui/qt/capture_interfaces_dialog.cpp b/ui/qt/capture_interfaces_dialog.cpp
index 3148e4fccc..d2969c0df7 100644
--- a/ui/qt/capture_interfaces_dialog.cpp
+++ b/ui/qt/capture_interfaces_dialog.cpp
@@ -704,10 +704,10 @@ void CaptureInterfacesDialog::updateInterfaces()
             if (capture_dev_user_snaplen_find(device->name, &hassnap, &snaplen)) {
                 /* Default snap length set in preferences */
                 device->snaplen = snaplen;
-                device->has_snaplen = snaplen == WTAP_MAX_PACKET_SIZE ? FALSE : hassnap;
+                device->has_snaplen = snaplen == WTAP_MAX_PACKET_SIZE_STANDARD ? FALSE : hassnap;
             } else {
                 /* No preferences set yet, use default values */
-                device->snaplen = WTAP_MAX_PACKET_SIZE;
+                device->snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
                 device->has_snaplen = FALSE;
             }
 
@@ -1009,7 +1009,7 @@ bool CaptureInterfacesDialog::saveOptionsToPreferences()
                 snaplen_list << QString("%1:%2(%3)")
                                 .arg(device->name)
                                 .arg(device->has_snaplen)
-                                .arg(device->has_snaplen ? device->snaplen : WTAP_MAX_PACKET_SIZE);
+                                .arg(device->has_snaplen ? device->snaplen : WTAP_MAX_PACKET_SIZE_STANDARD);
             }
             g_free(prefs.capture_devices_snaplen);
             prefs.capture_devices_snaplen = qstring_strdup(snaplen_list.join(","));
@@ -1197,7 +1197,7 @@ QWidget* InterfaceTreeDelegate::createEditor(QWidget *parent, const QStyleOption
 #ifdef SHOW_BUFFER_COLUMN
     gint buffer = DEFAULT_CAPTURE_BUFFER_SIZE;
 #endif
-    guint snap = WTAP_MAX_PACKET_SIZE;
+    guint snap = WTAP_MAX_PACKET_SIZE_STANDARD;
     GList *links = NULL;
 
     if (idx.column() > 1 && idx.data().toString().compare(UTF8_EM_DASH)) {
@@ -1247,7 +1247,7 @@ QWidget* InterfaceTreeDelegate::createEditor(QWidget *parent, const QStyleOption
         case col_snaplen_:
         {
             QSpinBox *sb = new QSpinBox(parent);
-            sb->setRange(1, WTAP_MAX_PACKET_SIZE);
+            sb->setRange(1, WTAP_MAX_PACKET_SIZE_STANDARD);
             sb->setValue(snap);
             sb->setWrapping(true);
             connect(sb, SIGNAL(valueChanged(int)), this, SLOT(snapshotLengthChanged(int)));
@@ -1258,7 +1258,7 @@ QWidget* InterfaceTreeDelegate::createEditor(QWidget *parent, const QStyleOption
         case col_buffer_:
         {
             QSpinBox *sb = new QSpinBox(parent);
-            sb->setRange(1, WTAP_MAX_PACKET_SIZE);
+            sb->setRange(1, WTAP_MAX_PACKET_SIZE_STANDARD);
             sb->setValue(buffer);
             sb->setWrapping(true);
             connect(sb, SIGNAL(valueChanged(int)), this, SLOT(bufferSizeChanged(int)));
@@ -1332,12 +1332,12 @@ void InterfaceTreeDelegate::snapshotLengthChanged(int value)
     if (!device) {
         return;
     }
-    if (value != WTAP_MAX_PACKET_SIZE) {
+    if (value != WTAP_MAX_PACKET_SIZE_STANDARD) {
         device->has_snaplen = true;
         device->snaplen = value;
     } else {
         device->has_snaplen = false;
-        device->snaplen = WTAP_MAX_PACKET_SIZE;
+        device->snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
     }
 }
 
diff --git a/ui/qt/compiled_filter_output.cpp b/ui/qt/compiled_filter_output.cpp
index ca718259a4..fda2332a33 100644
--- a/ui/qt/compiled_filter_output.cpp
+++ b/ui/qt/compiled_filter_output.cpp
@@ -88,7 +88,7 @@ void CompiledFilterOutput::compileFilter()
             if (interfaces.compare(device.display_name)) {
                 continue;
             } else {
-                pcap_t *pd = pcap_open_dead(device.active_dlt, WTAP_MAX_PACKET_SIZE);
+                pcap_t *pd = pcap_open_dead(device.active_dlt, WTAP_MAX_PACKET_SIZE_STANDARD);
                 if (pd == NULL)
                     break;
                 g_mutex_lock(pcap_compile_mtx);
diff --git a/ui/qt/gsm_map_summary_dialog.cpp b/ui/qt/gsm_map_summary_dialog.cpp
index 4b8c50747d..a13b116047 100644
--- a/ui/qt/gsm_map_summary_dialog.cpp
+++ b/ui/qt/gsm_map_summary_dialog.cpp
@@ -128,7 +128,7 @@ QString GsmMapSummaryDialog::summaryToHtml()
         << table_data_tmpl.arg(format_str)
         << table_row_end;
 
-    if (summary.has_snap) {
+    if (summary.snap != 0) {
         out << table_row_begin
             << table_vheader_tmpl.arg(tr("Snapshot length"))
             << table_data_tmpl.arg(summary.snap)
diff --git a/ui/qt/interface_tree_cache_model.cpp b/ui/qt/interface_tree_cache_model.cpp
index e89e266868..5447f80332 100644
--- a/ui/qt/interface_tree_cache_model.cpp
+++ b/ui/qt/interface_tree_cache_model.cpp
@@ -210,7 +210,7 @@ void InterfaceTreeCacheModel::save()
                 else if ( col == IFTREE_COL_SNAPLEN )
                 {
                     int iVal = saveValue.toInt();
-                    if ( iVal != WTAP_MAX_PACKET_SIZE )
+                    if ( iVal != WTAP_MAX_PACKET_SIZE_STANDARD )
                     {
                         device.has_snaplen = true;
                         device.snaplen = iVal;
@@ -218,7 +218,7 @@ void InterfaceTreeCacheModel::save()
                     else
                     {
                         device.has_snaplen = false;
-                        device.snaplen = WTAP_MAX_PACKET_SIZE;
+                        device.snaplen = WTAP_MAX_PACKET_SIZE_STANDARD;
                     }
                 }
 #ifdef CAN_SET_CAPTURE_BUFFER_SIZE
@@ -270,7 +270,7 @@ void InterfaceTreeCacheModel::save()
                 prefStorage[&prefs.capture_devices_snaplen]  <<
                         QString("%1:%2(%3)").arg(device.name).
                         arg(device.has_snaplen ? 1 : 0).
-                        arg(device.has_snaplen ? value : WTAP_MAX_PACKET_SIZE);
+                        arg(device.has_snaplen ? value : WTAP_MAX_PACKET_SIZE_STANDARD);
             }
 
 #ifdef CAN_SET_CAPTURE_BUFFER_SIZE
diff --git a/ui/qt/mtp3_summary_dialog.cpp b/ui/qt/mtp3_summary_dialog.cpp
index 62fcc7107c..3affcc94b2 100644
--- a/ui/qt/mtp3_summary_dialog.cpp
+++ b/ui/qt/mtp3_summary_dialog.cpp
@@ -133,7 +133,7 @@ QString Mtp3SummaryDialog::summaryToHtml()
         << table_data_tmpl.arg(format_str)
         << table_row_end;
 
-    if (summary.has_snap) {
+    if (summary.snap != 0) {
         out << table_row_begin
             << table_vheader_tmpl.arg(tr("Snapshot length"))
             << table_data_tmpl.arg(summary.snap)
diff --git a/ui/tap_export_pdu.c b/ui/tap_export_pdu.c
index 76e4326ab3..3624e88c42 100644
--- a/ui/tap_export_pdu.c
+++ b/ui/tap_export_pdu.c
@@ -146,7 +146,7 @@ exp_pdu_open(exp_pdu_t *exp_pdu_tap_data, int fd, char *comment)
     int_data_mand = (wtapng_if_descr_mandatory_t*)wtap_block_get_mandatory_data(int_data);
     int_data_mand->wtap_encap      = WTAP_ENCAP_WIRESHARK_UPPER_PDU;
     int_data_mand->time_units_per_second = 1000000000; /* default nanosecond resolution */
-    int_data_mand->snap_len        = WTAP_MAX_PACKET_SIZE;
+    int_data_mand->snap_len        = WTAP_MAX_PACKET_SIZE_STANDARD;
 
     wtap_block_add_string_option(int_data, OPT_IDB_NAME, "Fake IF, PDU->Export", strlen("Fake IF, PDU->Export"));
     wtap_block_add_uint8_option(int_data, OPT_IDB_TSRESOL, 9);
@@ -156,7 +156,7 @@ exp_pdu_open(exp_pdu_t *exp_pdu_tap_data, int fd, char *comment)
     g_array_append_val(shb_hdrs, shb_hdr);
 
     /* Use a random name for the temporary import buffer */
-    exp_pdu_tap_data->wdh = wtap_dump_fdopen_ng(fd, WTAP_FILE_TYPE_SUBTYPE_PCAPNG, WTAP_ENCAP_WIRESHARK_UPPER_PDU, WTAP_MAX_PACKET_SIZE, FALSE,
+    exp_pdu_tap_data->wdh = wtap_dump_fdopen_ng(fd, WTAP_FILE_TYPE_SUBTYPE_PCAPNG, WTAP_ENCAP_WIRESHARK_UPPER_PDU, WTAP_MAX_PACKET_SIZE_STANDARD, FALSE,
         shb_hdrs, idb_inf, NULL, &err);
     if (exp_pdu_tap_data->wdh == NULL) {
         g_assert(err != 0);
diff --git a/ui/text_import.h b/ui/text_import.h
index 46f619421c..71ee2a2948 100644
--- a/ui/text_import.h
+++ b/ui/text_import.h
@@ -37,7 +37,7 @@
 extern "C" {
 #endif /* __cplusplus */
 
-#define IMPORT_MAX_PACKET WTAP_MAX_PACKET_SIZE
+#define IMPORT_MAX_PACKET WTAP_MAX_PACKET_SIZE_STANDARD
 
 /* The parameter interface */