subsys/net/lib/mqtt/mqtt_transport_socket_tcp.c

/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/** @file mqtt_transport_socket_tcp.h
 *
 * @brief Internal functions to handle transport over TCP socket.
 */

#include <logging/log.h>
LOG_MODULE_REGISTER(net_mqtt_sock_tcp, CONFIG_MQTT_LOG_LEVEL);

#include <errno.h>
#include <net/socket.h>
#include <net/mqtt.h>

#include "mqtt_os.h"

/**@brief Handles connect request for TCP socket transport.
 *
 * @param[in] client Identifies the client on which the procedure is requested.
 *
 * @retval 0 or an error code indicating reason for failure.
 */
int mqtt_client_tcp_connect(struct mqtt_client *client)
{
	const struct sockaddr *broker = client->broker;
	int ret;

	client->transport.tcp.sock = socket(broker->sa_family, SOCK_STREAM,
					    IPPROTO_TCP);
	if (client->transport.tcp.sock < 0) {
		return -errno;
	}

	MQTT_TRC("Created socket %d", client->transport.tcp.sock);

	size_t peer_addr_size = sizeof(struct sockaddr_in6);

	if (broker->sa_family == AF_INET) {
		peer_addr_size = sizeof(struct sockaddr_in);
	}

	ret = connect(client->transport.tcp.sock, client->broker,
		      peer_addr_size);
	if (ret < 0) {
		(void)close(client->transport.tcp.sock);
		return -errno;
	}

	MQTT_TRC("Connect completed");
	return 0;
}

/**@brief Handles write requests on TCP socket transport.
 *
 * @param[in] client Identifies the client on which the procedure is requested.
 * @param[in] data Data to be written on the transport.
 * @param[in] datalen Length of data to be written on the transport.
 *
 * @retval 0 or an error code indicating reason for failure.
 */
int mqtt_client_tcp_write(struct mqtt_client *client, const u8_t *data,
			  u32_t datalen)
{
	u32_t offset = 0U;
	int ret;

	while (offset < datalen) {
		ret = send(client->transport.tcp.sock, data + offset,
			   datalen - offset, 0);
		if (ret < 0) {
			return -errno;
		}

		offset += ret;
	}

	return 0;
}

/**@brief Handles read requests on TCP socket transport.
 *
 * @param[in] client Identifies the client on which the procedure is requested.
 * @param[in] data Pointer where read data is to be fetched.
 * @param[in] buflen Size of memory provided for the operation.
 *
 * @retval Number of bytes read or an error code indicating reason for failure.
 *         0 if connection was closed.
 */
int mqtt_client_tcp_read(struct mqtt_client *client, u8_t *data, u32_t buflen)
{
	int ret;

	ret = recv(client->transport.tcp.sock, data, buflen, MSG_DONTWAIT);
	if (ret < 0) {
		return -errno;
	}

	return ret;
}

/**@brief Handles transport disconnection requests on TCP socket transport.
 *
 * @param[in] client Identifies the client on which the procedure is requested.
 *
 * @retval 0 or an error code indicating reason for failure.
 */
int mqtt_client_tcp_disconnect(struct mqtt_client *client)
{
	int ret;

	MQTT_TRC("Closing socket %d", client->transport.tcp.sock);

	ret = close(client->transport.tcp.sock);
	if (ret < 0) {
		return -errno;
	}

	return 0;
}