aws_iot_mqtt_client.h

/*
 * Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

// Based on Eclipse Paho.
/*******************************************************************************
 * Copyright (c) 2014 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Ian Craggs - initial API and implementation and/or initial documentation
 *    Xiang Rong - 442039 Add makefile to Embedded C client
 *******************************************************************************/

/**
 * @file aws_iot_mqtt_client.h
 * @brief Client definition for MQTT
 */

#ifndef AWS_IOT_SDK_SRC_IOT_MQTT_CLIENT_H
#define AWS_IOT_SDK_SRC_IOT_MQTT_CLIENT_H

#ifdef __cplusplus
extern "C" {
#endif

/* Library Header files */
#include "stdio.h"
#include "stdbool.h"
#include "stdint.h"
#include "stddef.h"

/* AWS Specific header files */
#include "aws_iot_error.h"
#include "aws_iot_config.h"

/* Platform specific implementation header files */
#include "network_interface.h"
#include "timer_interface.h"

#ifdef _ENABLE_THREAD_SUPPORT_
#include "threads_interface.h"
#endif

#define MAX_PACKET_ID 65535

typedef struct _Client AWS_IoT_Client;

/**
 * @brief Quality of Service Type
 *
 * Defining a QoS type.
 * @note QoS 2 is \b NOT supported by the AWS IoT Service at the time of this SDK release.
 *
 */
typedef enum QoS {
	QOS0 = 0,
	QOS1 = 1
} QoS;

/**
 * @brief Publish Message Parameters Type
 *
 * Defines a type for MQTT Publish messages. Used for both incoming and out going messages
 *
 */
typedef struct {
	QoS qos;		///< Message Quality of Service
	uint8_t isRetained;	///< Retained messages are \b NOT supported by the AWS IoT Service at the time of this SDK release.
	uint8_t isDup;		///< Is this message a duplicate QoS > 0 message?  Handled automatically by the MQTT client.
	uint16_t id;		///< Message sequence identifier.  Handled automatically by the MQTT client.
	void *payload;		///< Pointer to MQTT message payload (bytes).
	size_t payloadLen;	///< Length of MQTT payload.
} IoT_Publish_Message_Params;

/**
 * @brief MQTT Version Type
 *
 * Defining an MQTT version type. Only 3.1.1 is supported at this time
 *
 */
typedef enum {
	MQTT_3_1_1 = 4    ///< MQTT 3.1.1 (protocol message byte = 4)
} MQTT_Ver_t;

/**
 * @brief Last Will and Testament Definition
 *
 * Defining a type for the MQTT "Last Will and Testament" (LWT) parameters.
 * @note Retained messages are \b NOT supported by the AWS IoT Service at the time of this SDK release.
 *
 */
typedef struct {
	char struct_id[4];		///< The eyecatcher for this structure.  must be MQTW
	char *pTopicName;		///< The LWT topic to which the LWT message will be published
	uint16_t topicNameLen;		///< The length of the LWT topic, 16 bit unsinged integer
	char *pMessage;			///< Message to be delivered as LWT
	uint16_t msgLen;		///< The length of the Message, 16 bit unsinged integer
	bool isRetained;		///< NOT supported. The retained flag for the LWT message (see MQTTAsync_message.retained)
	QoS qos;			///< QoS of LWT message
} IoT_MQTT_Will_Options;
extern const IoT_MQTT_Will_Options iotMqttWillOptionsDefault;

#define IoT_MQTT_Will_Options_Initializer { {'M', 'Q', 'T', 'W'}, NULL, 0, NULL, 0, false, QOS0 }

/**
 * @brief MQTT Connection Parameters
 *
 * Defining a type for MQTT connection parameters.  Passed into client when establishing a connection.
 *
 */
typedef struct {
	char struct_id[4];			///< The eyecatcher for this structure.  must be MQTC
	MQTT_Ver_t MQTTVersion;			///< Desired MQTT version used during connection
	char *pClientID;                	///< Pointer to a string defining the MQTT client ID (this needs to be unique \b per \b device across your AWS account)
	uint16_t clientIDLen;			///< Client Id Length. 16 bit unsigned integer
	uint16_t keepAliveIntervalInSec;	///< MQTT keep alive interval in seconds.  Defines inactivity time allowed before determining the connection has been lost.
	bool isCleanSession;			///< MQTT clean session.  True = this session is to be treated as clean.  Previous server state is cleared and no stated is retained from this connection.
	bool isWillMsgPresent;			///< Is there a LWT associated with this connection?
	IoT_MQTT_Will_Options will;		///< MQTT LWT parameters.
	char *pUsername;			///< Not used in the AWS IoT Service, will need to be cstring if used
	uint16_t usernameLen;			///< Username Length. 16 bit unsigned integer
	char *pPassword;			///< Not used in the AWS IoT Service, will need to be cstring if used
	uint16_t passwordLen;			///< Password Length. 16 bit unsigned integer
} IoT_Client_Connect_Params;
extern const IoT_Client_Connect_Params iotClientConnectParamsDefault;

#define IoT_Client_Connect_Params_initializer { {'M', 'Q', 'T', 'C'}, MQTT_3_1_1, NULL, 0, 60, true, false, \
        IoT_MQTT_Will_Options_Initializer, NULL, 0, NULL, 0 }

/**
 * @brief Disconnect Callback Handler Type
 *
 * Defining a TYPE for definition of disconnect callback function pointers.
 *
 */
typedef void (*iot_disconnect_handler)(AWS_IoT_Client *, void *);

/**
 * @brief MQTT Initialization Parameters
 *
 * Defining a type for MQTT initialization parameters.
 * Passed into client when to initialize the client
 *
 */
typedef struct {
	bool enableAutoReconnect;			///< Set to true to enable auto reconnect
	char *pHostURL;					///< Pointer to a string defining the endpoint for the MQTT service
	uint16_t port;					///< MQTT service listening port
	char *pRootCALocation;				///< Pointer to a string defining the Root CA file (full file, not path)
	char *pDeviceCertLocation;			///< Pointer to a string defining the device identity certificate file (full file, not path)
	char *pDevicePrivateKeyLocation;        	///< Pointer to a string defining the device private key file (full file, not path)
	uint32_t mqttPacketTimeout_ms;			///< Timeout for reading a complete MQTT packet. In milliseconds
	uint32_t mqttCommandTimeout_ms;			///< Timeout for MQTT blocking calls. In milliseconds
	uint32_t tlsHandshakeTimeout_ms;		///< TLS handshake timeout.  In milliseconds
	bool isSSLHostnameVerify;			///< Client should perform server certificate hostname validation
	iot_disconnect_handler disconnectHandler;	///< Callback to be invoked upon connection loss
	void *disconnectHandlerData;			///< Data to pass as argument when disconnect handler is called
#ifdef _ENABLE_THREAD_SUPPORT_
	bool isBlockOnThreadLockEnabled;		///< Timeout for Thread blocking calls. Set to 0 to block until lock is obtained. In milliseconds
#endif
} IoT_Client_Init_Params;
extern const IoT_Client_Init_Params iotClientInitParamsDefault;

#ifdef _ENABLE_THREAD_SUPPORT_
#define IoT_Client_Init_Params_initializer { true, NULL, 0, NULL, NULL, NULL, 2000, 20000, 5000, true, NULL, NULL, false }
#else
#define IoT_Client_Init_Params_initializer { true, NULL, 0, NULL, NULL, NULL, 2000, 20000, 5000, true, NULL, NULL }
#endif

/**
 * @brief MQTT Client State Type
 *
 * Defining a type for MQTT Client State
 *
 */
typedef enum _ClientState {
	CLIENT_STATE_INVALID = 0,
	CLIENT_STATE_INITIALIZED = 1,
	CLIENT_STATE_CONNECTING = 2,
	CLIENT_STATE_CONNECTED_IDLE = 3,
	CLIENT_STATE_CONNECTED_YIELD_IN_PROGRESS = 4,
	CLIENT_STATE_CONNECTED_PUBLISH_IN_PROGRESS = 5,
	CLIENT_STATE_CONNECTED_SUBSCRIBE_IN_PROGRESS = 6,
	CLIENT_STATE_CONNECTED_UNSUBSCRIBE_IN_PROGRESS = 7,
	CLIENT_STATE_CONNECTED_RESUBSCRIBE_IN_PROGRESS = 8,
	CLIENT_STATE_CONNECTED_WAIT_FOR_CB_RETURN = 9,
	CLIENT_STATE_DISCONNECTING = 10,
	CLIENT_STATE_DISCONNECTED_ERROR = 11,
	CLIENT_STATE_DISCONNECTED_MANUALLY = 12,
	CLIENT_STATE_PENDING_RECONNECT = 13
} ClientState;

/**
 * @brief Application Callback Handler Type
 *
 * Defining a TYPE for definition of application callback function pointers.
 * Used to send incoming data to the application
 *
 */
typedef void (*pApplicationHandler_t)(AWS_IoT_Client *pClient, char *pTopicName, uint16_t topicNameLen,
									  IoT_Publish_Message_Params *pParams, void *pClientData);

/**
 * @brief MQTT Message Handler
 *
 * Defining a type for MQTT Message Handlers.
 * Used to pass incoming data back to the application
 *
 */
typedef struct _MessageHandlers {
	const char *topicName;
	uint16_t topicNameLen;
	char resubscribed;
	QoS qos;
	pApplicationHandler_t pApplicationHandler;
	void *pApplicationHandlerData;
} MessageHandlers;   /* Message handlers are indexed by subscription topic */

/**
 * @brief MQTT Client Status
 *
 * Defining a type for MQTT Client Status
 * Contains information about the state of the MQTT Client
 *
 */
typedef struct _ClientStatus {
	ClientState clientState;
	bool isPingOutstanding;
	bool isAutoReconnectEnabled;
} ClientStatus;

/**
 * @brief MQTT Client Data
 *
 * Defining a type for MQTT Client Data
 * Contains data used by the MQTT Client
 *
 */
typedef struct _ClientData {
	uint16_t nextPacketId;

	uint32_t packetTimeoutMs;
	uint32_t commandTimeoutMs;
	uint16_t keepAliveInterval;
	uint32_t currentReconnectWaitInterval;
	uint32_t counterNetworkDisconnected;

	/* The below values are initialized with the
	 * lengths of the TX/RX buffers and never modified
	 * afterwards */
	size_t writeBufSize;
	size_t readBufSize;
    size_t readBufIndex;
	unsigned char writeBuf[AWS_IOT_MQTT_TX_BUF_LEN];
	unsigned char readBuf[AWS_IOT_MQTT_RX_BUF_LEN];

#ifdef _ENABLE_THREAD_SUPPORT_
	bool isBlockOnThreadLockEnabled;
	IoT_Mutex_t state_change_mutex;
	IoT_Mutex_t tls_read_mutex;
	IoT_Mutex_t tls_write_mutex;
#endif

	IoT_Client_Connect_Params options;

	MessageHandlers messageHandlers[AWS_IOT_MQTT_NUM_SUBSCRIBE_HANDLERS];
	iot_disconnect_handler disconnectHandler;

	void *disconnectHandlerData;
} ClientData;

/**
 * @brief MQTT Client
 *
 * Defining a type for MQTT Client
 *
 */
struct _Client {
	Timer pingTimer;
	Timer reconnectDelayTimer;

	ClientStatus clientStatus;
	ClientData clientData;
	Network networkStack;
};

/**
 * @brief What is the next available packet Id
 *
 * Called to retrieve the next packet id to be used for outgoing packets.
 * Automatically increments the last sent packet id variable
 *
 * @param pClient Reference to the IoT Client
 *
 * @return next packet id as a 16 bit unsigned integer
 */
uint16_t aws_iot_mqtt_get_next_packet_id(AWS_IoT_Client *pClient);

/**
 * @brief Set the connection parameters for the IoT Client
 *
 * Called to set the connection parameters for the IoT Client.
 * Used to update the connection parameters provided before the last connect.
 * Won't take effect until the next time connect is called
 *
 * @param pClient Reference to the IoT Client
 * @param pNewConnectParams Reference to the new Connection Parameters structure
 *
 * @return IoT_Error_t Type defining successful/failed API call
 */
IoT_Error_t aws_iot_mqtt_set_connect_params(AWS_IoT_Client *pClient, IoT_Client_Connect_Params *pNewConnectParams);

/**
 * @brief Is the MQTT client currently connected?
 *
 * Called to determine if the MQTT client is currently connected.  Used to support logic
 * in the device application around reconnecting and managing offline state.
 *
 * @param pClient Reference to the IoT Client
 *
 * @return true = connected, false = not currently connected
 */
bool aws_iot_mqtt_is_client_connected(AWS_IoT_Client *pClient);

/**
 * @brief Get the current state of the client
 *
 * Called to get the current state of the client
 *
 * @param pClient Reference to the IoT Client
 *
 * @return ClientState value equal to the current state of the client
 */
ClientState aws_iot_mqtt_get_client_state(AWS_IoT_Client *pClient);

/**
 * @brief Is the MQTT client set to reconnect automatically?
 *
 * Called to determine if the MQTT client is set to reconnect automatically.
 * Used to support logic in the device application around reconnecting
 *
 * @param pClient Reference to the IoT Client
 *
 * @return true = enabled, false = disabled
 */
bool aws_iot_is_autoreconnect_enabled(AWS_IoT_Client *pClient);

/**
 * @brief Set the IoT Client disconnect handler
 *
 * Called to set the IoT Client disconnect handler
 * The disconnect handler is called whenever the client disconnects with error
 *
 * @param pClient Reference to the IoT Client
 * @param pConnectHandler Reference to the new Disconnect Handler
 * @param pDisconnectHandlerData Reference to the data to be passed as argument when disconnect handler is called
 *
 * @return IoT_Error_t Type defining successful/failed API call
 */
IoT_Error_t aws_iot_mqtt_set_disconnect_handler(AWS_IoT_Client *pClient, iot_disconnect_handler pDisconnectHandler,
												void *pDisconnectHandlerData);

/**
 * @brief Enable or Disable AutoReconnect on Network Disconnect
 *
 * Called to enable or disabled the auto reconnect features provided with the SDK
 *
 * @param pClient Reference to the IoT Client
 * @param newStatus set to true for enabling and false for disabling
 *
 * @return IoT_Error_t Type defining successful/failed API call
 */
IoT_Error_t aws_iot_mqtt_autoreconnect_set_status(AWS_IoT_Client *pClient, bool newStatus);

/**
 * @brief Get count of Network Disconnects
 *
 * Called to get the number of times a network disconnect occurred due to errors
 *
 * @param pClient Reference to the IoT Client
 *
 * @return uint32_t the disconnect count
 */
uint32_t aws_iot_mqtt_get_network_disconnected_count(AWS_IoT_Client *pClient);

/**
 * @brief Reset Network Disconnect conter
 *
 * Called to reset the Network Disconnect counter to zero
 *
 * @param pClient Reference to the IoT Client
 */
void aws_iot_mqtt_reset_network_disconnected_count(AWS_IoT_Client *pClient);

#ifdef __cplusplus
}
#endif

#endif