res/res_pjsip: Purge contacts when an AoR is deleted

When an AoR is deleted by an external mechanism, such as through ARI, we
currently do not remove dynamic contacts that were created for that AoR as a
result of a received REGISTER request. As a result, re-creating the AoR will
cause the dynamic contact to be interpreted as a persistent contact, leading
to some rather strange state being created for the contacts/endpoints.

This patch adds a sorcery observer for the 'aor' object. When a delete is
issued on the underlying sorcery object, the observer is called, and all
contacts created and persisted in sorcery for that AoR are also removed. Note
that we don't want to perform this action when an AO2 object that is an AoR is
destroyed, as the AoR can still exist in the backing storage (and we would
thus be removing valid contacts from an AoR that still "exists".)

ASTERISK-25381 #close

Change-Id: I6697e51ef6b2858b5d63401f35dc378bb0f90328

res/res_pjsip/location.c

@@ -47,6 +47,41 @@ static void *aor_alloc(const char *name)
 	return aor;
 }
 
+/*! \brief Internal callback function which destroys the specified contact */
+static int destroy_contact(void *obj, void *arg, int flags)
+{
+	struct ast_sip_contact *contact = obj;
+
+	ast_sip_location_delete_contact(contact);
+
+	return CMP_MATCH;
+}
+
+static void aor_deleted_observer(const void *object)
+{
+	const char *aor_id = ast_sorcery_object_get_id(object);
+	/* Give enough space for ^ at the beginning and ;@ at the end, since that is our object naming scheme */
+	char regex[strlen(aor_id) + 4];
+	struct ao2_container *contacts;
+
+	snprintf(regex, sizeof(regex), "^%s;@", aor_id);
+
+	if (!(contacts = ast_sorcery_retrieve_by_regex(ast_sip_get_sorcery(), "contact", regex))) {
+		return;
+	}
+
+	/* Destroy any contacts that may still exist that were made for this AoR */
+	ao2_callback(contacts, OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK, destroy_contact, NULL);
+
+	ao2_ref(contacts, -1);
+}
+
+/*! \brief Observer for contacts so state can be updated on respective endpoints */
+static const struct ast_sorcery_observer aor_observer = {
+	.deleted = aor_deleted_observer,
+};
+
+
 /*! \brief Destructor for contact */
 static void contact_destroy(void *obj)
 {
@@ -910,6 +945,8 @@ int ast_sip_initialize_sorcery_location(void)
 		return -1;
 	}
 
+	ast_sorcery_observer_add(sorcery, "aor", &aor_observer);
+
 	ast_sorcery_object_field_register(sorcery, "contact", "type", "", OPT_NOOP_T, 0, 0);
 	ast_sorcery_object_field_register(sorcery, "contact", "uri", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_contact, uri));
 	ast_sorcery_object_field_register(sorcery, "contact", "path", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct ast_sip_contact, path));
@@ -971,6 +1008,7 @@ int ast_sip_initialize_sorcery_location(void)
 
 int ast_sip_destroy_sorcery_location(void)
 {
+	ast_sorcery_observer_remove(ast_sip_get_sorcery(), "aor", &aor_observer);
 	ast_cli_unregister_multiple(cli_commands, ARRAY_LEN(cli_commands));
 	ast_sip_unregister_cli_formatter(contact_formatter);
 	ast_sip_unregister_cli_formatter(aor_formatter);