[nrf fromtree] net: mqtt: Add MQTT 5.0 support for DISCONNECT

Add support for DICONNECT message specified in MQTT 5.0.
As with MQTT 5.0, the disconnect can now also be initiated by the
broker, it was needed to add decoder support for the message.

Signed-off-by: Robert Lubos <[email protected]>
(cherry picked from commit 55e1c10)

Author: rlubos

include/zephyr/net/mqtt.h

@@ -175,6 +175,39 @@ enum mqtt_suback_return_code {
 	MQTT_SUBACK_FAILURE = 0x80
 };
 
+/** @brief MQTT Disconnect reason codes (MQTT 5.0, chapter 3.14.2.1). */
+enum mqtt_disconnect_reason_code {
+	MQTT_DISCONNECT_NORMAL = 0,
+	MQTT_DISCONNECT_WITH_WILL_MSG = 4,
+	MQTT_DISCONNECT_UNSPECIFIED_ERROR = 128,
+	MQTT_DISCONNECT_MALFORMED_PACKET = 129,
+	MQTT_DISCONNECT_PROTOCOL_ERROR = 130,
+	MQTT_DISCONNECT_IMPL_SPECIFIC_ERROR = 131,
+	MQTT_DISCONNECT_NOT_AUTHORIZED = 135,
+	MQTT_DISCONNECT_SERVER_BUSY = 137,
+	MQTT_DISCONNECT_SERVER_SHUTTING_DOWN = 139,
+	MQTT_DISCONNECT_KEEP_ALIVE_TIMEOUT = 141,
+	MQTT_DISCONNECT_SESSION_TAKE_OVER = 142,
+	MQTT_DISCONNECT_TOPIC_FILTER_INVALID = 143,
+	MQTT_DISCONNECT_TOPIC_NAME_INVALID = 144,
+	MQTT_DISCONNECT_RECV_MAX_EXCEEDED = 147,
+	MQTT_DISCONNECT_TOPIC_ALIAS_INVALID = 148,
+	MQTT_DISCONNECT_PACKET_TOO_LARGE = 149,
+	MQTT_DISCONNECT_MESSAGE_RATE_TOO_HIGH = 150,
+	MQTT_DISCONNECT_QUOTA_EXCEEDED = 151,
+	MQTT_DISCONNECT_ADMIN_ACTION = 152,
+	MQTT_DISCONNECT_PAYLOAD_FORMAT_INVALID = 153,
+	MQTT_DISCONNECT_RETAIN_NOT_SUPPORTED = 154,
+	MQTT_DISCONNECT_QOS_NOT_SUPPORTED = 155,
+	MQTT_DISCONNECT_USE_ANOTHER_SERVER = 156,
+	MQTT_DISCONNECT_SERVER_MOVED = 157,
+	MQTT_DISCONNECT_SHARED_SUB_NOT_SUPPORTED = 158,
+	MQTT_DISCONNECT_CONNECTION_RATE_EXCEEDED = 159,
+	MQTT_DISCONNECT_MAX_CONNECT_TIME = 160,
+	MQTT_DISCONNECT_SUB_ID_NOT_SUPPORTED = 161,
+	MQTT_DISCONNECT_WILDCARD_SUB_NOT_SUPPORTED = 162,
+};
+
 /** @brief Abstracts UTF-8 encoded strings. */
 struct mqtt_utf8 {
 	const uint8_t *utf8;       /**< Pointer to UTF-8 string. */
@@ -534,6 +567,41 @@ struct mqtt_subscription_list {
 #endif /* CONFIG_MQTT_VERSION_5_0 */
 };
 
+/** @brief Parameters for disconnect message. */
+struct mqtt_disconnect_param {
+#if defined(CONFIG_MQTT_VERSION_5_0)
+	/* MQTT 5.0 Disconnect reason code. */
+	enum mqtt_disconnect_reason_code reason_code;
+
+	/** MQTT 5.0 properties. */
+	struct {
+		/** MQTT 5.0, chapter 3.14.2.2.4 User Property. */
+		struct mqtt_utf8_pair user_prop[CONFIG_MQTT_USER_PROPERTIES_MAX];
+
+		/** MQTT 5.0, chapter 3.14.2.2.3 Reason String. */
+		struct mqtt_utf8 reason_string;
+
+		/** MQTT 5.0, chapter 3.14.2.2.5 Server Reference. */
+		struct mqtt_utf8 server_reference;
+
+		/** MQTT 5.0, chapter 3.14.2.2.2 Session Expiry Interval. */
+		uint32_t session_expiry_interval;
+
+		/** Flags indicating whether given property was present in received packet. */
+		struct {
+			/** Session Expiry Interval property was present. */
+			bool has_session_expiry_interval;
+			/** Reason String property was present. */
+			bool has_reason_string;
+			/** User Property property was present. */
+			bool has_user_prop;
+			/** Server Reference property was present. */
+			bool has_server_reference;
+		} rx;
+	} prop;
+#endif /* CONFIG_MQTT_VERSION_5_0 */
+};
+
 /**
  * @brief Defines event parameters notified along with asynchronous events
  *        to the application.
@@ -567,6 +635,11 @@ union mqtt_evt_param {
 
 	/** Parameters accompanying MQTT_EVT_UNSUBACK event. */
 	struct mqtt_unsuback_param unsuback;
+
+#if defined(CONFIG_MQTT_VERSION_5_0)
+	/** Parameters accompanying MQTT_EVT_DISCONNECT event. */
+	struct mqtt_disconnect_param disconnect;
+#endif /* CONFIG_MQTT_VERSION_5_0 */
 };
 
 /** @brief Defines MQTT asynchronous event notified to the application. */
@@ -1042,10 +1115,13 @@ int mqtt_ping(struct mqtt_client *client);
  *
  * @param[in] client Identifies client instance for which procedure is
  *                   requested.
+ * @param[in] param Optional Disconnect parameters. May be NULL.
+ *                  Ignored if MQTT 3.1.1 is used.
  *
  * @return 0 or a negative error code (errno.h) indicating reason of failure.
  */
-int mqtt_disconnect(struct mqtt_client *client);
+int mqtt_disconnect(struct mqtt_client *client,
+		    const struct mqtt_disconnect_param *param);
 
 /**
  * @brief API to abort MQTT connection. This will close the corresponding

samples/net/cloud/aws_iot_mqtt/src/main.c

@@ -413,7 +413,7 @@ void aws_client_loop(void)
 	}
 
 cleanup:
-	mqtt_disconnect(&client_ctx);
+	mqtt_disconnect(&client_ctx, NULL);
 
 	close(fds.fd);
 	fds.fd = -1;

samples/net/mqtt_publisher/src/main.c

@@ -475,7 +475,7 @@ static int publisher(void)
 		r = 0;
 	}
 
-	rc = mqtt_disconnect(&client_ctx);
+	rc = mqtt_disconnect(&client_ctx, NULL);
 	PRINT_RESULT("mqtt_disconnect", rc);
 
 	LOG_INF("Bye!");

samples/net/secure_mqtt_sensor_actuator/src/mqtt_client.c

@@ -402,7 +402,7 @@ void app_mqtt_run(struct mqtt_client *client)
 		}
 	}
 	/* Gracefully close connection */
-	mqtt_disconnect(client);
+	mqtt_disconnect(client, NULL);
 }
 
 void app_mqtt_connect(struct mqtt_client *client)

subsys/net/lib/mqtt/mqtt.c

@@ -46,8 +46,7 @@ void event_notify(struct mqtt_client *client, const struct mqtt_evt *evt)
 	}
 }
 
-static void client_disconnect(struct mqtt_client *client, int result,
-			      bool notify)
+void mqtt_client_disconnect(struct mqtt_client *client, int result, bool notify)
 {
 	int err_code;
 
@@ -105,7 +104,7 @@ static int client_connect(struct mqtt_client *client)
 	return 0;
 
 error:
-	client_disconnect(client, err_code, false);
+	mqtt_client_disconnect(client, err_code, false);
 	return err_code;
 }
 
@@ -119,7 +118,7 @@ static int client_read(struct mqtt_client *client)
 
 	err_code = mqtt_handle_rx(client);
 	if (err_code < 0) {
-		client_disconnect(client, err_code, true);
+		mqtt_client_disconnect(client, err_code, true);
 	}
 
 	return err_code;
@@ -136,7 +135,7 @@ static int client_write(struct mqtt_client *client, const uint8_t *data,
 	if (err_code < 0) {
 		NET_ERR("Transport write failed, err_code = %d, "
 			 "closing connection", err_code);
-		client_disconnect(client, err_code, true);
+		mqtt_client_disconnect(client, err_code, true);
 		return err_code;
 	}
 
@@ -157,7 +156,7 @@ static int client_write_msg(struct mqtt_client *client,
 	if (err_code < 0) {
 		NET_ERR("Transport write failed, err_code = %d, "
 			 "closing connection", err_code);
-		client_disconnect(client, err_code, true);
+		mqtt_client_disconnect(client, err_code, true);
 		return err_code;
 	}
 
@@ -439,7 +438,8 @@ int mqtt_publish_qos2_complete(struct mqtt_client *client,
 	return err_code;
 }
 
-int mqtt_disconnect(struct mqtt_client *client)
+int mqtt_disconnect(struct mqtt_client *client,
+		    const struct mqtt_disconnect_param *param)
 {
 	int err_code;
 	struct buf_ctx packet;
@@ -455,7 +455,7 @@ int mqtt_disconnect(struct mqtt_client *client)
 		goto error;
 	}
 
-	err_code = disconnect_encode(&packet);
+	err_code = disconnect_encode(client, param, &packet);
 	if (err_code < 0) {
 		goto error;
 	}
@@ -465,7 +465,7 @@ int mqtt_disconnect(struct mqtt_client *client)
 		goto error;
 	}
 
-	client_disconnect(client, 0, true);
+	mqtt_client_disconnect(client, 0, true);
 
 error:
 	mqtt_mutex_unlock(client);
@@ -584,7 +584,7 @@ int mqtt_abort(struct mqtt_client *client)
 	mqtt_mutex_lock(client);
 
 	if (client->internal.state != MQTT_STATE_IDLE) {
-		client_disconnect(client, -ECONNABORTED, true);
+		mqtt_client_disconnect(client, -ECONNABORTED, true);
 	}
 
 	mqtt_mutex_unlock(client);
@@ -686,7 +686,7 @@ static int read_publish_payload(struct mqtt_client *client, void *buffer,
 			ret = -ENOTCONN;
 		}
 
-		client_disconnect(client, ret, true);
+		mqtt_client_disconnect(client, ret, true);
 		goto exit;
 	}
 

subsys/net/lib/mqtt/mqtt_decoder.c

@@ -1015,3 +1015,67 @@ int unsubscribe_ack_decode(const struct mqtt_client *client, struct buf_ctx *buf
 
 	return 0;
 }
+
+#if defined(CONFIG_MQTT_VERSION_5_0)
+static int disconnect_properties_decode(struct buf_ctx *buf,
+					struct mqtt_disconnect_param *param)
+{
+	struct property_decoder prop[] = {
+		{
+			&param->prop.session_expiry_interval,
+			&param->prop.rx.has_session_expiry_interval,
+			MQTT_PROP_SESSION_EXPIRY_INTERVAL
+		},
+		{
+			&param->prop.reason_string,
+			&param->prop.rx.has_reason_string,
+			MQTT_PROP_REASON_STRING
+		},
+		{
+			&param->prop.user_prop,
+			&param->prop.rx.has_user_prop,
+			MQTT_PROP_USER_PROPERTY
+		},
+		{
+			&param->prop.server_reference,
+			&param->prop.rx.has_server_reference,
+			MQTT_PROP_SERVER_REFERENCE
+		}
+	};
+
+	return properties_decode(prop, ARRAY_SIZE(prop), buf);
+}
+
+int disconnect_decode(const struct mqtt_client *client, struct buf_ctx *buf,
+		      struct mqtt_disconnect_param *param)
+{
+
+	size_t remaining_len;
+	uint8_t reason_code;
+	int err;
+
+	if (!mqtt_is_version_5_0(client)) {
+		return -ENOTSUP;
+	}
+
+	remaining_len = buf->end - buf->cur;
+
+	if (remaining_len > 0) {
+		err = unpack_uint8(buf, &reason_code);
+		if (err < 0) {
+			return err;
+		}
+
+		param->reason_code = reason_code;
+	}
+
+	if (remaining_len > 1) {
+		err = disconnect_properties_decode(buf, param);
+		if (err < 0) {
+			return err;
+		}
+	}
+
+	return 0;
+}
+#endif /* CONFIG_MQTT_VERSION_5_0 */