1 files changed, 365 insertions, 0 deletions

diff --git a/nrfdemo/src/mqtt_connection.c b/nrfdemo/src/mqtt_connection.c
new file mode 100644
index 0000000..ef4e69f
--- /dev/null
+++ b/nrfdemo/src/mqtt_connection.c
@@ -0,0 +1,365 @@
+#include <stdio.h>
+#include <string.h>
+#include <ncs_version.h>
+
+#include <zephyr/logging/log.h>
+#include <zephyr/kernel.h>
+#include <zephyr/net/socket.h>
+#include <zephyr/net/mqtt.h>
+#include <nrf_modem_at.h>
+
+#include <dk_buttons_and_leds.h>
+#include "mqtt_connection.h"
+
+#if NCS_VERSION_NUMBER < 0x20600
+#include <zephyr/random/rand32.h>
+#else 
+#include <zephyr/random/random.h>
+#endif
+
+/* Buffers for MQTT client. */
+static uint8_t rx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
+static uint8_t tx_buffer[CONFIG_MQTT_MESSAGE_BUFFER_SIZE];
+static uint8_t payload_buf[CONFIG_MQTT_PAYLOAD_BUFFER_SIZE];
+
+/* MQTT Broker details. */
+static struct sockaddr_storage broker;
+
+LOG_MODULE_DECLARE(mqtt_app);
+
+/**@brief Function to get the payload of recived data.
+ */
+static int get_received_payload(struct mqtt_client *c, size_t length)
+{
+	int ret;
+	int err = 0;
+
+	/* Return an error if the payload is larger than the payload buffer.
+	 * Note: To allow new messages, we have to read the payload before returning.
+	 */
+	if (length > sizeof(payload_buf)) {
+		err = -EMSGSIZE;
+	}
+
+	/* Truncate payload until it fits in the payload buffer. */
+	while (length > sizeof(payload_buf)) {
+		ret = mqtt_read_publish_payload_blocking(
+				c, payload_buf, (length - sizeof(payload_buf)));
+		if (ret == 0) {
+			return -EIO;
+		} else if (ret < 0) {
+			return ret;
+		}
+
+		length -= ret;
+	}
+
+	ret = mqtt_readall_publish_payload(c, payload_buf, length);
+	if (ret) {
+		return ret;
+	}
+
+	return err;
+}
+
+/**@brief Function to subscribe to the configured topic
+ */
+/* Define the function subscribe() to subscribe to a specific topic.  */
+static int subscribe(struct mqtt_client *const c)
+{
+	struct mqtt_topic subscribe_topic = {
+		.topic = {
+			.utf8 = CONFIG_MQTT_SUB_TOPIC,
+			.size = strlen(CONFIG_MQTT_SUB_TOPIC)
+		},
+		.qos = MQTT_QOS_1_AT_LEAST_ONCE
+	};
+
+	const struct mqtt_subscription_list subscription_list = {
+		.list = &subscribe_topic,
+		.list_count = 1,
+		.message_id = 1234
+	};
+
+	LOG_INF("Subscribing to: %s len %u", CONFIG_MQTT_SUB_TOPIC,
+		(unsigned int)strlen(CONFIG_MQTT_SUB_TOPIC));
+
+	return mqtt_subscribe(c, &subscription_list);
+}
+
+/**@brief Function to print strings without null-termination
+ */
+static void data_print(uint8_t *prefix, uint8_t *data, size_t len)
+{
+	char buf[len + 1];
+
+	memcpy(buf, data, len);
+	buf[len] = 0;
+	LOG_INF("%s%s", (char *)prefix, (char *)buf);
+}
+
+/**@brief Function to publish data on the configured topic
+ */
+/* Define the function data_publish() to publish data */
+int data_publish(struct mqtt_client *c, enum mqtt_qos qos,
+	uint8_t *data, size_t len)
+{
+	struct mqtt_publish_param param;
+
+	param.message.topic.qos = qos;
+	param.message.topic.topic.utf8 = CONFIG_MQTT_PUB_TOPIC;
+	param.message.topic.topic.size = strlen(CONFIG_MQTT_PUB_TOPIC);
+	param.message.payload.data = data;
+	param.message.payload.len = len;
+	param.message_id = sys_rand32_get();
+	param.dup_flag = 0;
+	param.retain_flag = 0;
+
+	data_print("Publishing: ", data, len);
+	LOG_INF("to topic: %s len: %u",
+		CONFIG_MQTT_PUB_TOPIC,
+		(unsigned int)strlen(CONFIG_MQTT_PUB_TOPIC));
+
+	return mqtt_publish(c, &param);
+}
+/**@brief MQTT client event handler
+ */
+void mqtt_evt_handler(struct mqtt_client *const c,
+		      const struct mqtt_evt *evt)
+{
+	int err;
+
+	switch (evt->type) {
+	case MQTT_EVT_CONNACK:
+	/* Subscribe to the topic CONFIG_MQTT_SUB_TOPIC when we have a successful connection */
+		if (evt->result != 0) {
+			LOG_ERR("MQTT connect failed: %d", evt->result);
+			break;
+		}
+
+		LOG_INF("MQTT client connected");
+		subscribe(c);
+		break;
+
+	case MQTT_EVT_DISCONNECT:
+		LOG_INF("MQTT client disconnected: %d", evt->result);
+		break;
+
+	case MQTT_EVT_PUBLISH:
+	/* Listen to published messages received from the broker and extract the message */
+	{
+		/* Extract the payload */
+		const struct mqtt_publish_param *p = &evt->param.publish;
+		//Print the length of the recived message 
+		LOG_INF("MQTT PUBLISH result=%d len=%d",
+			evt->result, p->message.payload.len);
+
+		//Extract the data of the recived message 
+		err = get_received_payload(c, p->message.payload.len);
+		
+		//Send acknowledgment to the broker on receiving QoS1 publish message 
+		if (p->message.topic.qos == MQTT_QOS_1_AT_LEAST_ONCE) {
+			const struct mqtt_puback_param ack = {
+				.message_id = p->message_id
+			};
+
+			/* Send acknowledgment. */
+			mqtt_publish_qos1_ack(c, &ack);
+		}
+
+		/* On successful extraction of data */
+		if (err >= 0) {
+			data_print("Received: ", payload_buf, p->message.payload.len);
+			// Control the LED 
+			if(strncmp(payload_buf,CONFIG_TURN_LED_ON_CMD,sizeof(CONFIG_TURN_LED_ON_CMD)-1) == 0){
+				dk_set_led_on(LED_CONTROL_OVER_MQTT);
+			}
+			else if(strncmp(payload_buf,CONFIG_TURN_LED_OFF_CMD,sizeof(CONFIG_TURN_LED_OFF_CMD)-1) == 0){
+				dk_set_led_off(LED_CONTROL_OVER_MQTT);
+			}
+		/* On failed extraction of data */
+		// Payload buffer is smaller than the received data 
+		} else if (err == -EMSGSIZE) {
+			LOG_ERR("Received payload (%d bytes) is larger than the payload buffer size (%d bytes).",
+				p->message.payload.len, sizeof(payload_buf));
+		// Failed to extract data, disconnect 
+		} else {
+			LOG_ERR("get_received_payload failed: %d", err);
+			LOG_INF("Disconnecting MQTT client...");
+
+			err = mqtt_disconnect(c);
+			if (err) {
+				LOG_ERR("Could not disconnect: %d", err);
+			}
+		}
+	} break;
+
+	case MQTT_EVT_PUBACK:
+		if (evt->result != 0) {
+			LOG_ERR("MQTT PUBACK error: %d", evt->result);
+			break;
+		}
+
+		LOG_INF("PUBACK packet id: %u", evt->param.puback.message_id);
+		break;
+
+	case MQTT_EVT_SUBACK:
+		if (evt->result != 0) {
+			LOG_ERR("MQTT SUBACK error: %d", evt->result);
+			break;
+		}
+
+		LOG_INF("SUBACK packet id: %u", evt->param.suback.message_id);
+		break;
+
+	case MQTT_EVT_PINGRESP:
+		if (evt->result != 0) {
+			LOG_ERR("MQTT PINGRESP error: %d", evt->result);
+		}
+		break;
+
+	default:
+		LOG_INF("Unhandled MQTT event type: %d", evt->type);
+		break;
+	}
+}
+
+/**@brief Resolves the configured hostname and
+ * initializes the MQTT broker structure
+ */
+static int broker_init(void)
+{
+	int err;
+	struct addrinfo *result;
+	struct addrinfo *addr;
+	struct addrinfo hints = {
+		.ai_family = AF_INET,
+		.ai_socktype = SOCK_STREAM
+	};
+
+	err = getaddrinfo(CONFIG_MQTT_BROKER_HOSTNAME, NULL, &hints, &result);
+	if (err) {
+		LOG_ERR("getaddrinfo failed: %d", err);
+		return -ECHILD;
+	}
+
+	addr = result;
+
+	/* Look for address of the broker. */
+	while (addr != NULL) {
+		/* IPv4 Address. */
+		if (addr->ai_addrlen == sizeof(struct sockaddr_in)) {
+			struct sockaddr_in *broker4 =
+				((struct sockaddr_in *)&broker);
+			char ipv4_addr[NET_IPV4_ADDR_LEN];
+
+			broker4->sin_addr.s_addr =
+				((struct sockaddr_in *)addr->ai_addr)
+				->sin_addr.s_addr;
+			broker4->sin_family = AF_INET;
+			broker4->sin_port = htons(CONFIG_MQTT_BROKER_PORT);
+
+			inet_ntop(AF_INET, &broker4->sin_addr.s_addr,
+				  ipv4_addr, sizeof(ipv4_addr));
+			LOG_INF("IPv4 Address found %s", (char *)(ipv4_addr));
+
+			break;
+		} else {
+			LOG_ERR("ai_addrlen = %u should be %u or %u",
+				(unsigned int)addr->ai_addrlen,
+				(unsigned int)sizeof(struct sockaddr_in),
+				(unsigned int)sizeof(struct sockaddr_in6));
+		}
+
+		addr = addr->ai_next;
+	}
+
+	/* Free the address. */
+	freeaddrinfo(result);
+
+	return err;
+}
+
+/* Function to get the client id */
+static const uint8_t* client_id_get(void)
+{
+	static uint8_t client_id[MAX(sizeof(CONFIG_MQTT_CLIENT_ID),
+				     CLIENT_ID_LEN)];
+
+	if (strlen(CONFIG_MQTT_CLIENT_ID) > 0) {
+		snprintf(client_id, sizeof(client_id), "%s",
+			 CONFIG_MQTT_CLIENT_ID);
+		goto exit;
+	}
+
+	char imei_buf[CGSN_RESPONSE_LENGTH + 1];
+	int err;
+
+	err = nrf_modem_at_cmd(imei_buf, sizeof(imei_buf), "AT+CGSN");
+	if (err) {
+		LOG_ERR("Failed to obtain IMEI, error: %d", err);
+		goto exit;
+	}
+
+	imei_buf[IMEI_LEN] = '\0';
+
+	snprintf(client_id, sizeof(client_id), "nrf-%.*s", IMEI_LEN, imei_buf);
+
+exit:
+	LOG_DBG("client_id = %s", (char *)(client_id));
+
+	return client_id;
+}
+
+
+/**@brief Initialize the MQTT client structure
+ */
+/* Define the function client_init() to initialize the MQTT client instance.  */
+int client_init(struct mqtt_client *client)
+{
+	int err;
+	/* Initializes the client instance. */
+	mqtt_client_init(client);
+
+	/* Resolves the configured hostname and initializes the MQTT broker structure */
+	err = broker_init();
+	if (err) {
+		LOG_ERR("Failed to initialize broker connection");
+		return err;
+	}
+
+	/* MQTT client configuration */
+	client->broker = &broker;
+	client->evt_cb = mqtt_evt_handler;
+	client->client_id.utf8 = client_id_get();
+	client->client_id.size = strlen(client->client_id.utf8);
+	client->password = NULL;
+	client->user_name = NULL;
+	client->protocol_version = MQTT_VERSION_3_1_1;
+
+	/* MQTT buffers configuration */
+	client->rx_buf = rx_buffer;
+	client->rx_buf_size = sizeof(rx_buffer);
+	client->tx_buf = tx_buffer;
+	client->tx_buf_size = sizeof(tx_buffer);
+
+	/* We are not using TLS */
+	client->transport.type = MQTT_TRANSPORT_NON_SECURE;
+
+	return err;
+}
+
+/**@brief Initialize the file descriptor structure used by poll.
+ */
+int fds_init(struct mqtt_client *c, struct pollfd *fds)
+{
+	if (c->transport.type == MQTT_TRANSPORT_NON_SECURE) {
+		fds->fd = c->transport.tcp.sock;
+	} else {
+		return -ENOTSUP;
+	}
+
+	fds->events = POLLIN;
+
+	return 0;
+}
\ No newline at end of file