From 45403b1804d2318aec2858c28ac4c623bfdcde2f Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <zecke@selfish.org>
Date: Mon, 3 May 2010 11:51:07 +0800
Subject: nat/bsc: Send PONG on PING, send PING from the BSC too

We do want to send PING/PONG in both ways to have a heartbeat
on the TCP connection. When switching over to SCTP we can rely
on the builtin heartbeat functionality.
---
 openbsc/src/bsc_msc_ip.c  | 53 ++++++++++++++++++++++++++++++++++++++++++++++-
 openbsc/src/nat/bsc_nat.c | 23 +++++++++++++++-----
 2 files changed, 70 insertions(+), 6 deletions(-)

diff --git a/openbsc/src/bsc_msc_ip.c b/openbsc/src/bsc_msc_ip.c
index 858a15c54..f760ad627 100644
--- a/openbsc/src/bsc_msc_ip.c
+++ b/openbsc/src/bsc_msc_ip.c
@@ -60,13 +60,17 @@ static struct log_target *stderr_target;
 struct gsm_network *bsc_gsmnet = 0;
 static const char *config_file = "openbsc.cfg";
 static char *msc_address = NULL;
-static struct bsc_msc_connection *msc_con;
 static struct in_addr local_addr;
 static LLIST_HEAD(active_connections);
 static struct write_queue mgcp_agent;
 static const char *rf_ctl = NULL;
 extern int ipacc_rtp_direct;
 
+/* msc handling */
+static struct bsc_msc_connection *msc_con;
+static struct timer_list msc_ping_timeout;
+static struct timer_list msc_pong_timeout;
+
 extern int bsc_bootstrap_network(int (*layer4)(struct gsm_network *, int, void *), const char *cfg_file);
 extern int bsc_shutdown_net(struct gsm_network *net);
 
@@ -867,10 +871,51 @@ static void msc_connection_was_lost(struct bsc_msc_connection *msc)
 		bss_force_close(bss);
 	}
 
+	bsc_del_timer(&msc_ping_timeout);
+	bsc_del_timer(&msc_pong_timeout);
+
 	msc->is_authenticated = 0;
 	bsc_msc_schedule_connect(msc);
 }
 
+static void msc_pong_timeout_cb(void *data)
+{
+	LOGP(DMSC, LOGL_ERROR, "MSC didn't answer PING. Closing connection.\n");
+	bsc_msc_lost(msc_con);
+}
+
+static void send_ping(void)
+{
+	struct msgb *msg;
+
+	msg = msgb_alloc_headroom(4096, 128, "ping");
+	if (!msg) {
+		LOGP(DMSC, LOGL_ERROR, "Failed to create PING.\n");
+		return;
+	}
+
+	msg->l2h = msgb_put(msg, 1);
+	msg->l2h[0] = IPAC_MSGT_PING;
+
+	msc_queue_write(msg, IPAC_PROTO_IPACCESS);
+}
+
+static void msc_ping_timeout_cb(void *data)
+{
+	send_ping();
+
+	/* send another ping in 20 seconds */
+	bsc_schedule_timer(&msc_ping_timeout, 20, 0);
+
+	/* also start a pong timer */
+	bsc_schedule_timer(&msc_pong_timeout, 5, 0);
+}
+
+static void msc_connection_connected(struct bsc_msc_connection *con)
+{
+	msc_ping_timeout_cb(con);
+}
+
 /*
  * callback with IP access data
  */
@@ -903,6 +948,8 @@ static int ipaccess_a_fd_cb(struct bsc_fd *bfd)
 			initialize_if_needed();
 		else if (msg->l2h[0] == IPAC_MSGT_ID_GET) {
 			send_id_get_response(bfd->fd);
+		} else if (msg->l2h[0] == IPAC_MSGT_PONG) {
+			bsc_del_timer(&msc_pong_timeout);
 		}
 	} else if (hh->proto == IPAC_PROTO_SCCP) {
 		sccp_system_incoming(msg);
@@ -1131,7 +1178,11 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	msc_ping_timeout.cb = msc_ping_timeout_cb;
+	msc_pong_timeout.cb = msc_pong_timeout_cb;
+
 	msc_con->connection_loss = msc_connection_was_lost;
+	msc_con->connected = msc_connection_connected;
 	msc_con->write_queue.read_cb = ipaccess_a_fd_cb;
 	msc_con->write_queue.write_cb = msc_sccp_do_write;
 	bsc_msc_connect(msc_con);
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index ca018e0c6..a60efd07c 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -117,6 +117,15 @@ static void send_ping(struct bsc_connection *bsc)
 	bsc_send_data(bsc, id_ping, sizeof(id_ping), IPAC_PROTO_IPACCESS);
 }
 
+static void send_pong(struct bsc_connection *bsc)
+{
+	static const u_int8_t id_pong[] = {
+		IPAC_MSGT_PONG,
+	};
+
+	bsc_send_data(bsc, id_pong, sizeof(id_pong), IPAC_PROTO_IPACCESS);
+}
+
 static void bsc_pong_timeout(void *_bsc)
 {
 	struct bsc_connection *bsc = _bsc;
@@ -646,6 +655,7 @@ static int ipaccess_bsc_read_cb(struct bsc_fd *bfd)
 	int error;
 	struct bsc_connection *bsc = bfd->data;
 	struct msgb *msg = ipaccess_read_msg(bfd, &error);
+	struct ipaccess_head *hh;
 
 	if (!msg) {
 		if (error == 0)
@@ -665,15 +675,18 @@ static int ipaccess_bsc_read_cb(struct bsc_fd *bfd)
 	LOGP(DNAT, LOGL_DEBUG, "MSG from BSC: %s proto: %d\n", hexdump(msg->data, msg->len), msg->l2h[0]);
 
 	/* Handle messages from the BSC */
-	if (bsc->authenticated) {
-		struct ipaccess_head *hh;
-		hh = (struct ipaccess_head *) msg->data;
+	hh = (struct ipaccess_head *) msg->data;
 
-		/* stop the pong timeout */
-		if (hh->proto == IPAC_PROTO_IPACCESS && msg->l2h[0] == IPAC_MSGT_PONG) {
+	/* stop the pong timeout */
+	if (hh->proto == IPAC_PROTO_IPACCESS) {
+		if (msg->l2h[0] == IPAC_MSGT_PONG) {
 			bsc_del_timer(&bsc->pong_timeout);
 			msgb_free(msg);
 			return 0;
+		} else if (msg->l2h[0] == IPAC_MSGT_PING) {
+			send_pong(bsc);
+			msgb_free(msg);
+			return 0;
 		}
 	}
 
-- 
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