logging: backend: net: use connection mgr

Use connection manager to deactivate and activate
net log backend.
This removes the warnings about dropped packages
completly.

Signed-off-by: Fin Maaß <f.maass@vogl-electronic.com>

Author: maass-hamburg

subsys/logging/backends/Kconfig.net

@@ -119,6 +119,17 @@ config LOG_BACKEND_NET_AUTOSTART
 	  started by the application later on. Otherwise the logging
 	  thread might block.
 
+config LOG_BACKEND_NET_USE_CONNECTION_MANAGER
+	bool "Use connection manager for start and stop networking backend"
+	depends on NET_CONNECTION_MANAGER
+	depends on LOG_BACKEND_NET_AUTOSTART
+	default y
+	help
+	  When enabled the connection manager will be used to start and stop
+	  the networking backend. This is useful when the application
+	  needs to wait for the network connection to be established before
+	  starting the logging backend.
+
 config LOG_BACKEND_NET_USE_DHCPV4_OPTION
 	bool "Use DHCPv4 Log Server Option to configure syslog server"
 	depends on NET_DHCPV4

subsys/logging/backends/log_backend_net.c

@@ -14,6 +14,7 @@ LOG_MODULE_REGISTER(log_backend_net, CONFIG_LOG_DEFAULT_LEVEL);
 #include <zephyr/logging/log_backend_net.h>
 #include <zephyr/net/hostname.h>
 #include <zephyr/net/net_if.h>
+#include <zephyr/net/net_mgmt.h>
 #include <zephyr/net/socket.h>
 
 /* Set this to 1 if you want to see what is being sent to server */
@@ -364,3 +365,24 @@ const struct log_backend *log_backend_net_get(void)
 {
 	return &log_backend_net;
 }
+
+#if defined(CONFIG_LOG_BACKEND_NET_USE_CONNECTION_MANAGER)
+static void l4_event_handler(uint32_t mgmt_event, struct net_if *iface, void *info,
+			     size_t info_length, void *user_data)
+{
+	ARG_UNUSED(iface);
+	ARG_UNUSED(info);
+	ARG_UNUSED(info_length);
+	ARG_UNUSED(user_data);
+
+	if (mgmt_event == NET_EVENT_L4_CONNECTED) {
+		log_backend_net_start();
+	} else if (mgmt_event == NET_EVENT_L4_DISCONNECTED) {
+		log_backend_deactivate(log_backend_net_get());
+	}
+}
+
+NET_MGMT_REGISTER_EVENT_HANDLER(log_backend_net_event_handler,
+				NET_EVENT_L4_CONNECTED | NET_EVENT_L4_DISCONNECTED,
+				&l4_event_handler, NULL);
+#endif /* CONFIG_LOG_BACKEND_NET_USE_CONNECTION_MANAGER */

subsys/net/lib/config/init.c

@@ -553,7 +553,8 @@ int net_config_init_app(const struct device *dev, const char *app_info)
 	/* This is activated late as it requires the network stack to be up
 	 * and running before syslog messages can be sent to network.
 	 */
-	if (IS_ENABLED(CONFIG_LOG_BACKEND_NET_AUTOSTART)) {
+	if (IS_ENABLED(CONFIG_LOG_BACKEND_NET_AUTOSTART) &&
+	    !IS_ENABLED(CONFIG_LOG_BACKEND_NET_USE_CONNECTION_MANAGER)) {
 		log_backend_net_start();
 	}
 

subsys/net/lib/dhcpv4/dhcpv4.c

@@ -1206,7 +1206,8 @@ static bool dhcpv4_parse_options(struct net_pkt *pkt,
 			log_backend_net_set_ip((struct sockaddr *)&log_server);
 
 			if (IS_ENABLED(CONFIG_LOG_BACKEND_NET_AUTOSTART) &&
-			    !IS_ENABLED(CONFIG_NET_CONFIG_SETTINGS)) {
+			    !IS_ENABLED(CONFIG_NET_CONFIG_SETTINGS) &&
+			    !IS_ENABLED(CONFIG_LOG_BACKEND_NET_USE_CONNECTION_MANAGER)) {
 				log_backend_net_start();
 			}