net: lib: coap: Introduce net mgmt events for CoAP

Allow users to register net mgmt events callbacks for CoAP events.

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>

include/zephyr/net/coap_mgmt.h

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2023 Basalte bv
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief CoAP Events code public header
+ */
+
+#ifndef ZEPHYR_INCLUDE_NET_COAP_MGMT_H_
+#define ZEPHYR_INCLUDE_NET_COAP_MGMT_H_
+
+#include <zephyr/net/net_mgmt.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief CoAP Manager Events
+ * @defgroup coap_mgmt CoAP Manager Events
+ * @ingroup networking
+ * @{
+ */
+
+/** @cond INTERNAL_HIDDEN */
+
+/* CoAP events */
+#define _NET_COAP_LAYER		NET_MGMT_LAYER_L4
+#define _NET_COAP_CODE		0x1c0
+#define _NET_COAP_IF_BASE	(NET_MGMT_EVENT_BIT |			\
+				 NET_MGMT_LAYER(_NET_COAP_LAYER) |	\
+				 NET_MGMT_LAYER_CODE(_NET_COAP_CODE))
+
+struct coap_service;
+struct coap_resource;
+struct coap_observer;
+
+/** @endcond */
+
+enum net_event_coap_cmd {
+	/* Service events */
+	NET_EVENT_COAP_CMD_SERVICE_STARTED = 1,
+	NET_EVENT_COAP_CMD_SERVICE_STOPPED,
+	/* Observer events */
+	NET_EVENT_COAP_CMD_OBSERVER_ADDED,
+	NET_EVENT_COAP_CMD_OBSERVER_REMOVED,
+};
+
+/**
+ * @brief coap_mgmt event raised when a service has started
+ */
+#define NET_EVENT_COAP_SERVICE_STARTED			\
+	(_NET_COAP_IF_BASE | NET_EVENT_COAP_CMD_SERVICE_STARTED)
+
+/**
+ * @brief coap_mgmt event raised when a service has stopped
+ */
+#define NET_EVENT_COAP_SERVICE_STOPPED			\
+	(_NET_COAP_IF_BASE | NET_EVENT_COAP_CMD_SERVICE_STOPPED)
+
+/**
+ * @brief coap_mgmt event raised when an observer has been added to a resource
+ */
+#define NET_EVENT_COAP_OBSERVER_ADDED			\
+	(_NET_COAP_IF_BASE | NET_EVENT_COAP_CMD_OBSERVER_ADDED)
+
+/**
+ * @brief coap_mgmt event raised when an observer has been removed from a resource
+ */
+#define NET_EVENT_COAP_OBSERVER_REMOVED			\
+	(_NET_COAP_IF_BASE | NET_EVENT_COAP_CMD_OBSERVER_REMOVED)
+
+/**
+ * @brief CoAP Service event structure.
+ */
+struct net_event_coap_service {
+	/* The CoAP service for which the event is emitted */
+	const struct coap_service *service;
+};
+
+/**
+ * @brief CoAP Observer event structure.
+ */
+struct net_event_coap_observer {
+	/* The CoAP resource for which the event is emitted */
+	struct coap_resource *resource;
+	/* The observer that is added/removed */
+	struct coap_observer *observer;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_NET_COAP_MGMT_H_ */

subsys/net/lib/coap/coap.c

@@ -23,6 +23,7 @@ LOG_MODULE_REGISTER(net_coap, CONFIG_COAP_LOG_LEVEL);
 #include <zephyr/net/net_ip.h>
 #include <zephyr/net/net_core.h>
 #include <zephyr/net/coap.h>
+#include <zephyr/net/coap_mgmt.h>
 
 #define COAP_PATH_ELEM_DELIM '/'
 #define COAP_PATH_ELEM_QUERY '?'
@@ -1844,6 +1845,25 @@ void coap_observer_init(struct coap_observer *observer,
 	net_ipaddr_copy(&observer->addr, addr);
 }
 
+static inline void coap_observer_raise_event(struct coap_resource *resource,
+					     struct coap_observer *observer,
+					     uint32_t mgmt_event)
+{
+#ifdef CONFIG_NET_MGMT_EVENT_INFO
+	const struct net_event_coap_observer net_event = {
+		.resource = resource,
+		.observer = observer,
+	};
+
+	net_mgmt_event_notify_with_info(mgmt_event, NULL, (void *)&net_event, sizeof(net_event));
+#else
+	ARG_UNUSED(resource);
+	ARG_UNUSED(observer);
+
+	net_mgmt_event_notify(mgmt_event, NULL);
+#endif
+}
+
 bool coap_register_observer(struct coap_resource *resource,
 			    struct coap_observer *observer)
 {
@@ -1856,13 +1876,21 @@ bool coap_register_observer(struct coap_resource *resource,
 		resource->age = 2;
 	}
 
+	coap_observer_raise_event(resource, observer, NET_EVENT_COAP_OBSERVER_ADDED);
+
 	return first;
 }
 
 bool coap_remove_observer(struct coap_resource *resource,
 			  struct coap_observer *observer)
 {
-	return sys_slist_find_and_remove(&resource->observers, &observer->list);
+	if (!sys_slist_find_and_remove(&resource->observers, &observer->list)) {
+		return false;
+	}
+
+	coap_observer_raise_event(resource, observer, NET_EVENT_COAP_OBSERVER_REMOVED);
+
+	return true;
 }
 
 static bool sockaddr_equal(const struct sockaddr *a,

subsys/net/lib/coap/coap_server.c

@@ -14,6 +14,7 @@ LOG_MODULE_DECLARE(net_coap, CONFIG_COAP_LOG_LEVEL);
 #include <zephyr/kernel.h>
 #include <zephyr/net/coap.h>
 #include <zephyr/net/coap_link_format.h>
+#include <zephyr/net/coap_mgmt.h>
 #include <zephyr/net/coap_service.h>
 #ifdef CONFIG_ARCH_POSIX
 #include <fcntl.h>
@@ -345,6 +346,21 @@ static inline bool coap_service_in_section(const struct coap_service *service)
 	       STRUCT_SECTION_END(coap_service) > service;
 }
 
+static inline void coap_service_raise_event(const struct coap_service *service, uint32_t mgmt_event)
+{
+#if defined(CONFIG_NET_MGMT_EVENT_INFO)
+	const struct net_event_coap_service net_event = {
+		.service = service,
+	};
+
+	net_mgmt_event_notify_with_info(mgmt_event, NULL, (void *)&net_event, sizeof(net_event));
+#else
+	ARG_UNUSED(service);
+
+	net_mgmt_event_notify(mgmt_event, NULL);
+#endif
+}
+
 int coap_service_start(const struct coap_service *service)
 {
 	int ret;
@@ -446,6 +462,8 @@ end:
 
 	coap_server_update_services();
 
+	coap_service_raise_event(service, NET_EVENT_COAP_SERVICE_STARTED);
+
 	return ret;
 
 close:
@@ -469,17 +487,18 @@ int coap_service_stop(const struct coap_service *service)
 	k_mutex_lock(&lock, K_FOREVER);
 
 	if (service->data->sock_fd < 0) {
-		ret = -EALREADY;
-		goto end;
+		k_mutex_unlock(&lock);
+		return -EALREADY;
 	}
 
 	/* Closing a socket will trigger a poll event */
 	ret = zsock_close(service->data->sock_fd);
 	service->data->sock_fd = -1;
 
-end:
 	k_mutex_unlock(&lock);
 
+	coap_service_raise_event(service, NET_EVENT_COAP_SERVICE_STOPPED);
+
 	return ret;
 }