Put the extcap interfaces at the *end* of the interface list.

The list should start with the native local interfaces, as returned by
pcap, so that we default to the interface pcap gives first, rather than
to whatever extcap interface happens to be at the beginning.

This also means that, if we're only calling extcap_interface_list() to
regenerate our internal data structures, we don't bother allocating -
and leaking! - a list of if_info structures.

Change-Id: Ida651b5b081883f118a300b9f57403f2dc5c4363
Ping-Bug: 12183
Reviewed-on: https://code.wireshark.org/review/14187
Reviewed-by: Guy Harris <guy@alum.mit.edu>

3 files changed, 37 insertions, 19 deletions

diff --git a/capchild/capture_ifinfo.c b/capchild/capture_ifinfo.c
index 3753ee2684..5c4f299415 100644
--- a/capchild/capture_ifinfo.c
+++ b/capchild/capture_ifinfo.c
@@ -106,10 +106,6 @@ capture_interface_list(int *err, char **err_str, void (*update_cb)(void))
     g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Capture Interface List ...");
 
     *err = 0;
-#ifdef HAVE_EXTCAP
-    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Loading External Capture Interface List ...");
-    if_list = extcap_interface_list(err_str);
-#endif
 
     /* Try to get our interface list */
     ret = sync_interface_list_open(&data, &primary_msg, &secondary_msg, update_cb);
@@ -200,6 +196,13 @@ capture_interface_list(int *err, char **err_str, void (*update_cb)(void))
         append_remote_list(if_list);
     }
 #endif
+
+#ifdef HAVE_EXTCAP
+    /* Add the extcap interfaces after the native and remote interfaces */
+    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Loading External Capture Interface List ...");
+    extcap_interface_list(&if_list, err_str);
+#endif
+
     return if_list;
 }
 
diff --git a/extcap.c b/extcap.c
index 245873a127..2c4444b12a 100644
--- a/extcap.c
+++ b/extcap.c
@@ -331,14 +331,16 @@ static gboolean interfaces_cb(const gchar *extcap, const gchar *ifname _U_, gcha
             g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "  Extcap [%s] ", int_iter->call);
 
         if ( int_iter->if_type == EXTCAP_SENTENCE_INTERFACE ) {
-            if_info = g_new0(if_info_t, 1);
-            if_info->name = g_strdup(int_iter->call);
-            if_info->friendly_name = g_strdup(int_iter->display);
+            if (il != NULL) {
+                if_info = g_new0(if_info_t, 1);
+                if_info->name = g_strdup(int_iter->call);
+                if_info->friendly_name = g_strdup(int_iter->display);
 
-            if_info->type = IF_EXTCAP;
+                if_info->type = IF_EXTCAP;
 
-            if_info->extcap = g_strdup(extcap);
-            *il = g_list_append(*il, if_info);
+                if_info->extcap = g_strdup(extcap);
+                *il = g_list_append(*il, if_info);
+            }
 
             extcap_if_add(int_iter->call, extcap);
         }
@@ -370,7 +372,7 @@ if_info_compare(gconstpointer a, gconstpointer b)
 GHashTable *
 extcap_tools_list(void) {
     if ( tools == NULL || g_hash_table_size(tools) == 0 )
-        extcap_interface_list(NULL);
+        extcap_interface_list(NULL, NULL);
 
     return tools;
 }
@@ -385,11 +387,13 @@ extcap_free_info (gpointer data) {
     g_free (info);
 }
 
-GList *
-extcap_interface_list(char **err_str) {
+void
+extcap_interface_list(GList **listp, char **err_str) {
     gchar *argv;
     /* gint i; */
     GList *ret = NULL;
+    GList *entry;
+    void *data;
 
     if (err_str != NULL)
         *err_str = NULL;
@@ -408,11 +412,22 @@ extcap_interface_list(char **err_str) {
 
     argv = g_strdup(EXTCAP_ARGUMENT_LIST_INTERFACES);
 
-    extcap_foreach(1, &argv, interfaces_cb, &ret, err_str, NULL);
+    extcap_foreach(1, &argv, interfaces_cb, (listp != NULL) ? &ret : NULL, err_str, NULL);
 
     g_free(argv);
 
-    return g_list_sort ( ret, if_info_compare );
+    if (listp != NULL) {
+        /* Sort the list */
+        ret = g_list_sort(ret, if_info_compare);
+
+        /* Append the interfaces to the list. */
+        while (ret != NULL) {
+            entry = g_list_first(ret);
+            data = entry->data;
+            ret = g_list_delete_link(ret, entry);
+            *listp = g_list_append(*listp, data);
+        }
+    }
 }
 
 static void extcap_free_arg_elem(gpointer data, gpointer user_data _U_) {
@@ -430,7 +445,7 @@ void extcap_register_preferences(void)
         return;
 
     if ( ! ifaces || g_hash_table_size(ifaces) == 0 )
-        extcap_interface_list(NULL);
+        extcap_interface_list(NULL, NULL);
 
     interfaces = g_hash_table_get_keys(ifaces);
 
diff --git a/extcap.h b/extcap.h
index 823c04af3c..d63cb17cb5 100644
--- a/extcap.h
+++ b/extcap.h
@@ -71,9 +71,9 @@ extcap_register_preferences(void);
 if_capabilities_t *
 extcap_get_if_dlts(const gchar * ifname, char ** err_str);
 
-/* get a list of all capture interfaces */
-GList *
-extcap_interface_list(char **err_str);
+/* append a list of all extcap capture interfaces to the specified list */
+void
+extcap_interface_list(GList **listp, char **err_str);
 
 /* get a list of all available extcap tools */
 GHashTable *