Fix 'Decode As' when used with IPv6-in-IPv6 packets

Add the ability to identify an instance of the dissector table to be modified by 'Decode As' thanks to pinfo->curr_layer_num
For now only IPv6 makes use of it but it could be extended to any other protocol
Also get rid of ipv6.nxt protocol: it is not required for 'Decode As' functionality and was colliding with ipv6.nxt field

Change-Id: I3c7403c77328ad7170e13af028d178f962a2b508
Reviewed-on: https://code.wireshark.org/review/10552
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: João Valverde <j@v6e.pt>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/ui/gtk/decode_as_dlg.c b/ui/gtk/decode_as_dlg.c
index e85fb74a6d..b752c4bb95 100644
--- a/ui/gtk/decode_as_dlg.c
+++ b/ui/gtk/decode_as_dlg.c
@@ -79,10 +79,11 @@
 #define E_LIST_S_MAX        E_LIST_S_TABLE
 #define E_LIST_S_COLUMNS   (E_LIST_S_MAX + 1)
 
-#define E_PAGE_LIST   "notebook_page_list"
-#define E_PAGE_TABLE  "notebook_page_table_name"
-#define E_PAGE_TITLE  "notebook_page_title"
-#define E_PAGE_VALUE  "notebook_page_value"
+#define E_PAGE_LIST           "notebook_page_list"
+#define E_PAGE_TABLE          "notebook_page_table_name"
+#define E_PAGE_TITLE          "notebook_page_title"
+#define E_PAGE_VALUE          "notebook_page_value"
+#define E_PAGE_CURR_LAYER_NUM "notebook_page_curr_layer_num"
 
 #define E_PAGE_ACTION "notebook_page_action"
 
@@ -671,12 +672,15 @@ decode_simple (GtkWidget *notebook_pg)
     /* Apply values to dissector table (stored in entry) */
     for (value_loop = 0; value_loop < entry->values[requested_index].num_values; value_loop++)
     {
+        guint8 saved_curr_layer_num = cfile.edt->pi.curr_layer_num;
+        cfile.edt->pi.curr_layer_num = (guint8)GPOINTER_TO_UINT(g_object_get_data(G_OBJECT(notebook_pg), E_PAGE_CURR_LAYER_NUM));
         value_ptr = entry->values[requested_index].build_values[value_loop](&cfile.edt->pi);
         if (abbrev != NULL && strcmp(abbrev, "(default)") == 0) {
             add_reset_list = entry->reset_value(table_name, value_ptr);
         } else {
             add_reset_list = entry->change_value(table_name, value_ptr, &handle, abbrev);
         }
+        cfile.edt->pi.curr_layer_num = saved_curr_layer_num;
 
         if (add_reset_list) {
             selector_type = g_new(guint,1);
@@ -1214,6 +1218,7 @@ decode_add_simple_page (decode_as_t *entry)
     if (entry->num_items == 1)
     {
         g_object_set_data(G_OBJECT(page), E_PAGE_VALUE, entry->values[0].build_values[0](&cfile.edt->pi));
+        g_object_set_data(G_OBJECT(page), E_PAGE_CURR_LAYER_NUM, GUINT_TO_POINTER(cfile.edt->pi.curr_layer_num));
 
         /* Always enabled */
         entry->values->label_func(&cfile.edt->pi, prompt);
@@ -1303,6 +1308,9 @@ decode_add_notebook (GtkWidget *format_hb)
     const char*        proto_name;
     GList             *list_entry;
     decode_as_t       *entry;
+    guint8             saved_curr_layer_num = cfile.edt->pi.curr_layer_num;
+
+    cfile.edt->pi.curr_layer_num = 1;
 
     /* Start a nootbook for flipping between sets of changes */
     notebook = gtk_notebook_new();
@@ -1332,8 +1340,11 @@ decode_add_notebook (GtkWidget *format_hb)
         }
 
         protos = wmem_list_frame_next(protos);
+        cfile.edt->pi.curr_layer_num++;
     }
 
+    cfile.edt->pi.curr_layer_num = saved_curr_layer_num;
+
     /* Select the last added page (selects first by default) */
     /* Notebook must be visible for set_page to work. */
     gtk_widget_show_all(notebook);