From 849d0a83e8598e0f21a3e9c5438c222d8ab417eb Mon Sep 17 00:00:00 2001
From: Jacob Erlbeck <jerlbeck@sysmocom.de>
Date: Thu, 18 Dec 2014 15:00:29 +0100
Subject: gprs: Add automatic re-connect if the GSUP connection is down

Currently the GSUP connection to a server is not restarted if the
connection cannot be established or is terminated during operation.

This commit adds a timer based connection mechanism, basically
consisting of a timer callback that calls gsup_client_connect. The
timer is eventually triggered (up == 0) or cleared (up != 0) by
gsup_client_updown_cb. It adds calls to osmo_timer_del() to
gsup_client_connect and gprs_gsup_client_destroy. The latter is now
called instead of talloc_free in gprs_gsup_client_create on error to
be on the safe side.

Sponsored-by: On-Waves ehf
---
 openbsc/include/openbsc/gprs_gsup_client.h |  7 +++
 openbsc/src/gprs/gprs_gsup_client.c        | 76 +++++++++++++++++++++++++++---
 2 files changed, 76 insertions(+), 7 deletions(-)

diff --git a/openbsc/include/openbsc/gprs_gsup_client.h b/openbsc/include/openbsc/gprs_gsup_client.h
index 89034e00a..1165c4a78 100644
--- a/openbsc/include/openbsc/gprs_gsup_client.h
+++ b/openbsc/include/openbsc/gprs_gsup_client.h
@@ -21,6 +21,10 @@
  */
 #pragma once
 
+#include <osmocom/core/timer.h>
+
+#define GPRS_GSUP_RECONNECT_INTERVAL 10
+
 struct msgb;
 struct ipa_client_conn;
 struct gprs_gsup_client;
@@ -32,6 +36,9 @@ struct gprs_gsup_client {
 	struct ipa_client_conn	*link;
 	gprs_gsup_read_cb_t	read_cb;
 	void			*data;
+
+	struct osmo_timer_list	connect_timer;
+	int			is_connected;
 };
 
 struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
diff --git a/openbsc/src/gprs/gprs_gsup_client.c b/openbsc/src/gprs/gprs_gsup_client.c
index 15988bcc8..52099005c 100644
--- a/openbsc/src/gprs/gprs_gsup_client.c
+++ b/openbsc/src/gprs/gprs_gsup_client.c
@@ -29,14 +29,69 @@
 #include <openbsc/debug.h>
 
 #include <errno.h>
+#include <string.h>
 
 extern void *tall_bsc_ctx;
 
+static int gsup_client_connect(struct gprs_gsup_client *gsupc)
+{
+	int rc;
+
+	if (gsupc->is_connected)
+		return 0;
+
+	if (osmo_timer_pending(&gsupc->connect_timer)) {
+		LOGP(DLINP, LOGL_DEBUG,
+		     "GSUP connect: connect timer already running\n");
+		osmo_timer_del(&gsupc->connect_timer);
+	}
+
+	rc = ipa_client_conn_open(gsupc->link);
+
+	if (rc >= 0)
+		return rc;
+
+	LOGP(DGPRS, LOGL_INFO, "GSUP failed to connect to %s:%d: %s\n",
+	     gsupc->link->addr, gsupc->link->port, strerror(-rc));
+
+	if (rc == -EBADF || rc == -ENOTSOCK || rc == -EAFNOSUPPORT ||
+	    rc == -EINVAL)
+		return rc;
+
+	osmo_timer_schedule(&gsupc->connect_timer, GPRS_GSUP_RECONNECT_INTERVAL, 0);
+
+	return 0;
+}
+
+static void connect_timer_cb(void *gsupc_)
+{
+	struct gprs_gsup_client *gsupc = gsupc_;
+
+	if (gsupc->is_connected)
+		return;
+
+	gsup_client_connect(gsupc);
+}
+
 static void gsup_client_updown_cb(struct ipa_client_conn *link, int up)
 {
+	struct gprs_gsup_client *gsupc = link->data;
+
 	LOGP(DGPRS, LOGL_NOTICE, "GSUP link to %s:%d %s\n",
 		     link->addr, link->port, up ? "UP" : "DOWN");
 
+	gsupc->is_connected = up;
+
+	if (up) {
+		/* TODO: Start ping procedure */
+
+		osmo_timer_del(&gsupc->connect_timer);
+	} else {
+		/* TODO: Stop ping procedure */
+
+		osmo_timer_schedule(&gsupc->connect_timer,
+				    GPRS_GSUP_RECONNECT_INTERVAL, 0);
+	}
 }
 
 static int gsup_client_read_cb(struct ipa_client_conn *link, struct msgb *msg)
@@ -90,26 +145,33 @@ struct gprs_gsup_client *gprs_gsup_client_create(const char *ip_addr,
 	if (!gsupc->link)
 		goto failed;
 
-	rc = ipa_client_conn_open(gsupc->link);
+	gsupc->connect_timer.data = gsupc;
+	gsupc->connect_timer.cb = &connect_timer_cb;
 
-	if (rc < 0 && rc != -EINPROGRESS) {
-		LOGP(DGPRS, LOGL_NOTICE, "GSUP failed to connect to %s:%d\n",
-		     ip_addr, tcp_port);
+	rc = gsup_client_connect(gsupc);
+
+	if (rc < 0 && rc != -EINPROGRESS)
 		goto failed;
-	}
 
 	gsupc->read_cb = read_cb;
 
 	return gsupc;
 
 failed:
-	talloc_free(gsupc);
+	gprs_gsup_client_destroy(gsupc);
 	return NULL;
 }
 
 void gprs_gsup_client_destroy(struct gprs_gsup_client *gsupc)
 {
-	ipa_client_conn_destroy(gsupc->link);
+	osmo_timer_del(&gsupc->connect_timer);
+
+	if (gsupc->link) {
+		ipa_client_conn_close(gsupc->link);
+		ipa_client_conn_destroy(gsupc->link);
+		gsupc->link = NULL;
+	}
+	talloc_free(gsupc);
 }
 
 int gprs_gsup_client_send(struct gprs_gsup_client *gsupc, struct msgb *msg)
-- 
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