--- chan_h323_ori.c	2009-04-30 07:14:58.000000000 +0800
+++ chan_h323_new.c	2009-10-16 09:19:56.000000000 +0800
@@ -134,6 +134,7 @@
 static int h323_signalling_port = 1720;
 static char gatekeeper[100];
 static int gatekeeper_disable = 1;
+static int gatekeeper_is_valid = 0;
 static int gatekeeper_discover = 0;
 static int gkroute = 0;
 /* Find user by alias (h.323 id) is default, alternative is the incomming call's source IP address*/
@@ -2892,6 +2893,7 @@
 	strcpy(default_context, "default");
 	h323_signalling_port = 1720;
 	gatekeeper_disable = 1;
+	gatekeeper_is_valid = 0;
 	gatekeeper_discover = 0;
 	gkroute = 0;
 	userbyalias = 1;
@@ -2963,11 +2965,14 @@
 		} else if (!strcasecmp(v->name, "gatekeeper")) {
 			if (!strcasecmp(v->value, "DISABLE")) {
 				gatekeeper_disable = 1;
+				gatekeeper_is_valid = 0;
 			} else if (!strcasecmp(v->value, "DISCOVER")) {
 				gatekeeper_disable = 0;
 				gatekeeper_discover = 1;
+				gatekeeper_is_valid = 1;
 			} else {
 				gatekeeper_disable = 0;
+				gatekeeper_is_valid = 1;
 				ast_copy_string(gatekeeper, v->value, sizeof(gatekeeper));
 			}
 		} else if (!strcasecmp(v->name, "secret")) {
@@ -3208,6 +3213,25 @@
 	.set_rtp_peer = oh323_set_rtp_peer,
 };
 
+static pthread_t gkreg_thread = AST_PTHREADT_NULL;
+static void *do_gkreg(void *data)
+{
+	while(1) {
+		sleep(120);
+		if(gatekeeper_is_valid && gatekeeper_disable) {
+			h323_gk_urq();
+			if (h323_set_gk(gatekeeper_discover, gatekeeper, secret)) {
+				ast_debug(1, "Gatekeeper registration failed.\n");
+			}else{
+				gatekeeper_disable = 0;
+				ast_debug(1, "Gatekeeper registration OK.\n");			
+			}
+		}
+	}
+	
+	return NULL;
+}
+
 static enum ast_module_load_result load_module(void)
 {
 	int res;
@@ -3307,6 +3331,11 @@
 		}
 		/* And start the monitor for the first time */
 		restart_monitor();
+		if (gkreg_thread == AST_PTHREADT_NULL) {
+			if (ast_pthread_create_background(&gkreg_thread, NULL, do_gkreg, NULL) < 0) {
+				ast_log(LOG_ERROR, "Unable to start gkreg_thread thread.\n");
+			}
+		}
 	}
 	return res;
 }