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>

1 files changed, 2 insertions, 2 deletions

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);