Have a heur_dissector_list_t be an opaque handle.

This allows dissector lists to be looked up by name, so they can be
shared by multiple dissectors.

(This means that there's no "udplite" heuristic dissector list, but
there shouldn't be one - protocols can run atop UDP or UDPLite equally
well, and they share a port namespace and uint dissector table, so they
should share a heuristic dissector table as well.)

Change-Id: Ifb2d2c294938c06d348a159adea7a57db8d770a7
Reviewed-on: https://code.wireshark.org/review/5936
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 24 insertions, 15 deletions

diff --git a/epan/packet.c b/epan/packet.c
index 8ffdfd8dd9..6a4664eb92 100644
--- a/epan/packet.c
+++ b/epan/packet.c
@@ -106,6 +106,10 @@ static GHashTable *dissector_tables = NULL;
  */
 static GHashTable *registered_dissectors = NULL;
 
+struct heur_dissector_list {
+	GSList		*list;
+};
+
 static GHashTable *heur_dissector_lists = NULL;
 
 static void
@@ -1878,10 +1882,10 @@ get_dissector_table_param(const char *name)
 }
 
 /* Finds a heuristic dissector table by table name. */
-heur_dissector_list_t *
+heur_dissector_list_t
 find_heur_dissector_list(const char *name)
 {
-	return (heur_dissector_list_t *)g_hash_table_lookup(heur_dissector_lists, name);
+	return (heur_dissector_list_t)g_hash_table_lookup(heur_dissector_lists, name);
 }
 
 gboolean
@@ -1892,7 +1896,7 @@ has_heur_dissector_list(const gchar *name) {
 void
 heur_dissector_add(const char *name, heur_dissector_t dissector, const int proto)
 {
-	heur_dissector_list_t *sub_dissectors = find_heur_dissector_list(name);
+	heur_dissector_list_t sub_dissectors = find_heur_dissector_list(name);
 	const char            *proto_name;
 	heur_dtbl_entry_t     *hdtbl_entry;
 
@@ -1921,7 +1925,7 @@ heur_dissector_add(const char *name, heur_dissector_t dissector, const int proto
 	hdtbl_entry->enabled   = TRUE;
 
 	/* do the table insertion */
-	*sub_dissectors = g_slist_prepend(*sub_dissectors, (gpointer)hdtbl_entry);
+	sub_dissectors->list = g_slist_prepend(sub_dissectors->list, (gpointer)hdtbl_entry);
 }
 
 
@@ -1937,7 +1941,7 @@ find_matching_heur_dissector( gconstpointer a, gconstpointer b) {
 
 void
 heur_dissector_delete(const char *name, heur_dissector_t dissector, const int proto) {
-	heur_dissector_list_t *sub_dissectors = find_heur_dissector_list(name);
+	heur_dissector_list_t  sub_dissectors = find_heur_dissector_list(name);
 	heur_dtbl_entry_t      hdtbl_entry;
 	GSList                *found_entry;
 
@@ -1948,18 +1952,18 @@ heur_dissector_delete(const char *name, heur_dissector_t dissector, const int pr
 
 	hdtbl_entry.protocol  = find_protocol_by_id(proto);
 
-	found_entry = g_slist_find_custom(*sub_dissectors, (gpointer) &hdtbl_entry, find_matching_heur_dissector);
+	found_entry = g_slist_find_custom(sub_dissectors->list, (gpointer) &hdtbl_entry, find_matching_heur_dissector);
 
 	if (found_entry) {
 		g_free(((heur_dtbl_entry_t *)(found_entry->data))->list_name);
 		g_slice_free(heur_dtbl_entry_t, found_entry->data);
-		*sub_dissectors = g_slist_delete_link(*sub_dissectors, found_entry);
+		sub_dissectors->list = g_slist_delete_link(sub_dissectors->list, found_entry);
 	}
 }
 
 void
 heur_dissector_set_enabled(const char *name, heur_dissector_t dissector, const int proto, const gboolean enabled) {
-	heur_dissector_list_t *sub_dissectors = find_heur_dissector_list(name);
+	heur_dissector_list_t  sub_dissectors = find_heur_dissector_list(name);
 	GSList                *found_entry;
 	heur_dtbl_entry_t      hdtbl_entry;
 
@@ -1970,7 +1974,7 @@ heur_dissector_set_enabled(const char *name, heur_dissector_t dissector, const i
 
 	hdtbl_entry.protocol  = find_protocol_by_id(proto);
 
-	found_entry = g_slist_find_custom(*sub_dissectors, (gpointer) &hdtbl_entry, find_matching_heur_dissector);
+	found_entry = g_slist_find_custom(sub_dissectors->list, (gpointer) &hdtbl_entry, find_matching_heur_dissector);
 
 	if (found_entry) {
 		heur_dtbl_entry_t *hdtbl_entry_p;
@@ -2012,7 +2016,8 @@ dissector_try_heuristic(heur_dissector_list_t sub_dissectors, tvbuff_t *tvb,
 	saved_layers_len = wmem_list_count(pinfo->layers);
 	*heur_dtbl_entry = NULL;
 
-	for (entry = sub_dissectors; entry != NULL; entry = g_slist_next(entry)) {
+	for (entry = sub_dissectors->list; entry != NULL;
+	    entry = g_slist_next(entry)) {
 		/* XXX - why set this now and above? */
 		pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
 		hdtbl_entry = (heur_dtbl_entry_t *)entry->data;
@@ -2100,12 +2105,12 @@ heur_dissector_table_foreach (const char  *table_name,
 			      gpointer     user_data)
 {
 	heur_dissector_foreach_info_t info;
-	heur_dissector_list_t        *list = find_heur_dissector_list(table_name);
+	heur_dissector_list_t         sub_dissectors = find_heur_dissector_list(table_name);
 
 	info.table_name    = table_name;
 	info.caller_func   = func;
 	info.caller_data   = user_data;
-        g_slist_foreach (*list, heur_dissector_table_foreach_func, &info);
+        g_slist_foreach (sub_dissectors->list, heur_dissector_table_foreach_func, &info);
 }
 
 /*
@@ -2199,15 +2204,19 @@ dissector_dump_heur_decodes(void)
 }
 
 
-void
-register_heur_dissector_list(const char *name, heur_dissector_list_t *sub_dissectors)
+heur_dissector_list_t
+register_heur_dissector_list(const char *name)
 {
+	heur_dissector_list_t sub_dissectors;
+
 	/* Make sure the registration is unique */
 	g_assert(g_hash_table_lookup(heur_dissector_lists, name) == NULL);
 
-	*sub_dissectors = NULL;	/* initially empty */
+	sub_dissectors = g_slice_new(struct heur_dissector_list);
+	sub_dissectors->list = NULL;	/* initially empty */
 	g_hash_table_insert(heur_dissector_lists, (gpointer)name,
 			    (gpointer) sub_dissectors);
+	return sub_dissectors;
 }
 
 /*