samples: net: echo-client: Start service in correct time

Start to monitor Connected and Disconnect events and then start
and stop the echo service according to system connectivity status.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

samples/net/sockets/echo_client/prj.conf

@@ -7,6 +7,7 @@ CONFIG_NET_IPV4=y
 CONFIG_NET_SOCKETS=y
 CONFIG_NET_SOCKETS_POSIX_NAMES=y
 CONFIG_NET_SOCKETS_POLL_MAX=4
+CONFIG_NET_CONNECTION_MANAGER=y
 
 # Kernel options
 CONFIG_MAIN_STACK_SIZE=2048

samples/net/sockets/echo_client/src/echo-client.c

@@ -27,6 +27,10 @@ LOG_MODULE_REGISTER(net_echo_client_sample, LOG_LEVEL_DBG);
 #include <net/socket.h>
 #include <net/tls_credentials.h>
 
+#include <net/net_mgmt.h>
+#include <net/net_event.h>
+#include <net/net_conn_mgr.h>
+
 #include "common.h"
 #include "ca_certificate.h"
 
@@ -34,6 +38,9 @@ LOG_MODULE_REGISTER(net_echo_client_sample, LOG_LEVEL_DBG);
 
 #define INVALID_SOCK (-1)
 
+#define EVENT_MASK (NET_EVENT_L4_CONNECTED | \
+		    NET_EVENT_L4_DISCONNECTED)
+
 /* Generated by http://www.lipsum.com/
  * 2 paragraphs, 179 words, 1160 bytes of Lorem Ipsum
  */
@@ -77,6 +84,8 @@ struct configs conf = {
 struct pollfd fds[4];
 int nfds;
 
+static struct net_mgmt_event_callback mgmt_cb;
+
 static void prepare_fds(void)
 {
 	if (conf.ipv4.udp.sock >= 0) {
@@ -114,6 +123,93 @@ static void wait(void)
 	}
 }
 
+static void start_udp_and_tcp(struct k_work *work)
+{
+	int ret;
+
+	LOG_INF("Starting...");
+
+	if (IS_ENABLED(CONFIG_NET_TCP)) {
+		ret = start_tcp();
+		if (ret < 0) {
+			return;
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_NET_UDP)) {
+		ret = start_udp();
+		if (ret < 0) {
+			return;
+		}
+	}
+
+	prepare_fds();
+
+	while (true) {
+		if (IS_ENABLED(CONFIG_NET_TCP)) {
+			ret = process_tcp();
+			if (ret < 0) {
+				break;
+			}
+		}
+
+		if (IS_ENABLED(CONFIG_NET_UDP)) {
+			ret = process_udp();
+			if (ret < 0) {
+				break;
+			}
+		}
+
+		wait();
+	}
+}
+
+static void stop_udp_and_tcp(struct k_work *work)
+{
+	LOG_INF("Stopping...");
+
+	if (IS_ENABLED(CONFIG_NET_UDP)) {
+		stop_udp();
+	}
+
+	if (IS_ENABLED(CONFIG_NET_TCP)) {
+		stop_tcp();
+	}
+}
+
+static void do_service(k_work_handler_t handler)
+{
+	static struct k_work work;
+
+	k_work_init(&work, handler);
+
+	k_work_submit(&work);
+}
+
+static void event_handler(struct net_mgmt_event_callback *cb,
+			  u32_t mgmt_event, struct net_if *iface)
+{
+	if ((mgmt_event & EVENT_MASK) != mgmt_event) {
+		return;
+	}
+
+	if (mgmt_event == NET_EVENT_L4_CONNECTED) {
+		LOG_INF("Network connected");
+
+		do_service(start_udp_and_tcp);
+
+		return;
+	}
+
+	if (mgmt_event == NET_EVENT_L4_DISCONNECTED) {
+		LOG_INF("Network disconnected");
+
+		do_service(stop_udp_and_tcp);
+
+		return;
+	}
+}
+
 static void init_app(void)
 {
 	LOG_INF(APP_BANNER);
@@ -128,57 +224,26 @@ static void init_app(void)
 	}
 #endif
 
+	if (IS_ENABLED(CONFIG_NET_CONNECTION_MANAGER)) {
+		net_mgmt_init_event_callback(&mgmt_cb,
+					     event_handler, EVENT_MASK);
+		net_mgmt_add_event_callback(&mgmt_cb);
+
+		net_conn_mgr_resend_status();
+	}
+
 	init_vlan();
 }
 
 void main(void)
 {
-	int ret;
-
 	init_app();
 
-	if (IS_ENABLED(CONFIG_NET_TCP)) {
-		ret = start_tcp();
-		if (ret < 0) {
-			goto quit;
-		}
-	}
-
-	if (IS_ENABLED(CONFIG_NET_UDP)) {
-		ret = start_udp();
-		if (ret < 0) {
-			goto quit;
-		}
-	}
-
-	prepare_fds();
-
-	while (true) {
-		if (IS_ENABLED(CONFIG_NET_TCP)) {
-			ret = process_tcp();
-			if (ret < 0) {
-				goto quit;
-			}
-		}
-
-		if (IS_ENABLED(CONFIG_NET_UDP)) {
-			ret = process_udp();
-			if (ret < 0) {
-				goto quit;
-			}
-		}
-
-		wait();
-	}
-
-quit:
-	LOG_INF("Stopping...");
-
-	if (IS_ENABLED(CONFIG_NET_UDP)) {
-		stop_udp();
-	}
-
-	if (IS_ENABLED(CONFIG_NET_TCP)) {
-		stop_tcp();
+	if (!IS_ENABLED(CONFIG_NET_CONNECTION_MANAGER)) {
+		/* If the config library has not been configured to start the
+		 * app only after we have a connection, then we can start
+		 * it right away.
+		 */
+		do_service(start_udp_and_tcp);
 	}
 }