If we don't have any preference set for the link-layer header type for

an interface, don't destroy the default link-layer header type from the
list of types.

I.e., first get the type from the preference (which sets the type to -1
if there isn't a preference), and then loop through the list of types
and, if there was no value obtained from the preference (i.e., the type
is -1), set it to the first type in the list.

Also, don't bother with the link-layer header type from the global
default options, as a global (all-interface) link-layer header type
makes little sense, given that the list of link-layer header types for
an interface depends on the type of interface and hence may differ from
interface to interface.

Fixes bug 9473.

svn path=/trunk/; revision=53581

1 files changed, 19 insertions, 6 deletions

diff --git a/ui/iface_lists.c b/ui/iface_lists.c
index baefd24f0d..bfdfe294b0 100644
--- a/ui/iface_lists.c
+++ b/ui/iface_lists.c
@@ -213,9 +213,27 @@ scan_local_interfaces(void (*update_cb)(void))
             device.monitor_mode_enabled = monitor_mode;
             device.monitor_mode_supported = caps->can_set_rfmon;
 #endif
+            /*
+             * If there's a preference for the link-layer header type for
+             * this interface, use it.
+             *
+             * The global capture options has a link-layer header type,
+             * but that's just because the capture options structure
+             * has one; a global link-layer header type makes little
+             * sense, as not all interfaces support the same sets of
+             * link-layer header types, so we don't use it.
+             */
+            device.active_dlt = capture_dev_user_linktype_find(if_info->name);
+
+            /*
+             * Process the list of link-layer header types.
+             * If the active link-layer header type wasn't set from a
+             * preference (meaning it's -1), default to the first
+             * link-layer header type in the list.
+             */
             for (lt_entry = caps->data_link_types; lt_entry != NULL; lt_entry = g_list_next(lt_entry)) {
                 data_link_info = (data_link_info_t *)lt_entry->data;
-                if (linktype_count == 0) {
+                if (linktype_count == 0 && device.active_dlt == -1) {
                     device.active_dlt = data_link_info->dlt;
                 }
                 link = (link_row *)g_malloc(sizeof(link_row));
@@ -229,11 +247,6 @@ scan_local_interfaces(void (*update_cb)(void))
                 device.links = g_list_append(device.links, link);
                 linktype_count++;
             }
-            if (linktype_count > 0) {
-                if ((device.active_dlt = capture_dev_user_linktype_find(if_info->name)) == -1) {
-                    device.active_dlt = global_capture_opts.default_options.linktype;
-                }
-            }
         } else {
 #if defined(HAVE_PCAP_CREATE)
             device.monitor_mode_enabled = FALSE;