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/*
* Copyright (c) 2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef _MQTT_H_
#define _MQTT_H_
#include <net/mqtt_types.h>
#include <net/net_context.h>
/**
* @brief MQTT library
* @defgroup mqtt MQTT library
* @{
*/
/**
* MQTT application type
*/
enum mqtt_app {
/** Publisher and Subscriber application */
MQTT_APP_PUBLISHER_SUBSCRIBER,
/** Publisher only application */
MQTT_APP_PUBLISHER,
/** Subscriber only application */
MQTT_APP_SUBSCRIBER,
/** MQTT Server */
MQTT_APP_SERVER
};
/**
* MQTT context structure
*
* @details Context structure for the MQTT high-level API with support for QoS.
*
* This API is designed for asynchronous operation, so callbacks are
* executed when some events must be addressed outside the MQTT routines.
* Those events are triggered by the reception or transmission of MQTT messages
* and are defined by the MQTT v3.1.1 spec, see:
*
* http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html
*
* For example, assume that Zephyr is operating as a MQTT_APP_SUBSCRIBER, so it
* may receive the MQTT PUBLISH and MQTT PUBREL (QoS2) messages. Once the
* messages are parsed and validated, the #publish_rx callback is executed.
*
* Internally, the #publish_rx callback must store the #mqtt_publish_msg message
* when a MQTT PUBLISH msg is received. When a MQTT PUBREL message is received,
* the application must evaluate if the PUBREL's Packet Identifier matches a
* previous received MQTT PUBLISH message. In this case, the user may provide a
* collection of #mqtt_publish_msg structs (array of structs) to store those
* messages.
*
* <b>NOTE: The application (and not the API) is in charge of keeping track of
* the state of the received and sent messages.</b>
*/
struct mqtt_ctx {
/** IP stack context structure */
struct net_context *net_ctx;
/** Network timeout for tx and rx routines */
int32_t net_timeout;
/** Callback executed when a MQTT CONNACK msg is received and validated.
* If this function pointer is not used, must be set to NULL.
*/
void (*connect)(struct mqtt_ctx *ctx);
/** Callback executed when a MQTT DISCONNECT msg is sent.
* If this function pointer is not used, must be set to NULL.
*/
void (*disconnect)(struct mqtt_ctx *ctx);
/** Callback executed when a #MQTT_APP_PUBLISHER application receives
* a MQTT PUBxxxx msg.
* If type is MQTT_PUBACK, MQTT_PUBCOMP or MQTT_PUBREC, this callback
* must return 0 if pkt_id matches the packet id of a previously
* received MQTT_PUBxxx message. If this callback returns 0, the caller
* will continue.
* Any other value will stop the QoS handshake and the caller will
* return -EINVAL. The application must discard all the messages
* already processed.
*
* <b>Note: this callback must be not NULL</b>
*
* @param [in] ctx MQTT context
* @param [in] pkt_id Packet Identifier for the input MQTT msg
* @param [in] type Packet type
*/
int (*publish_tx)(struct mqtt_ctx *ctx, uint16_t pkt_id,
enum mqtt_packet type);
/** Callback executed when a MQTT_APP_SUBSCRIBER,
* MQTT_APP_PUBLISHER_SUBSCRIBER or MQTT_APP_SERVER applications receive
* a MQTT PUBxxxx msg. If this callback returns 0, the caller will
* continue. If type is MQTT_PUBREL this callback must return 0 if
* pkt_id matches the packet id of a previously received MQTT_PUBxxx
* message. Any other value will stop the QoS handshake and the caller
* will return -EINVAL
*
* <b>Note: this callback must be not NULL</b>
*
* @param [in] ctx MQTT context
* @param [in] msg Publish message, this parameter is only used
* when the type is MQTT_PUBLISH
* @param [in] pkt_id Packet Identifier for the input msg
* @param [in] type Packet type
*/
int (*publish_rx)(struct mqtt_ctx *ctx, struct mqtt_publish_msg *msg,
uint16_t pkt_id, enum mqtt_packet type);
/** Callback executed when a MQTT_APP_SUBSCRIBER or
* MQTT_APP_PUBLISHER_SUBSCRIBER receives the MQTT SUBACK message
* If this callback returns 0, the caller will continue. Any other
* value will make the caller return -EINVAL.
*
* <b>Note: this callback must be not NULL</b>
*
* @param [in] ctx MQTT context
* @param [in] pkt_id Packet Identifier for the MQTT SUBACK msg
* @param [in] items Number of elements in the qos array
* @param [in] qos Array of QoS values
*/
int (*subscribe)(struct mqtt_ctx *ctx, uint16_t pkt_id,
uint8_t items, enum mqtt_qos qos[]);
/** Callback executed when a MQTT_APP_SUBSCRIBER or
* MQTT_APP_PUBLISHER_SUBSCRIBER receives the MQTT UNSUBACK message
* If this callback returns 0, the caller will continue. Any other value
* will make the caller return -EINVAL
*
* <b>Note: this callback must be not NULL</b>
*
* @param [in] ctx MQTT context
* @param [in] pkt_id Packet Identifier for the MQTT SUBACK msg
*/
int (*unsubscribe)(struct mqtt_ctx *ctx, uint16_t pkt_id);
/** Callback executed when an incoming message doesn't pass the
* validation stage. This callback may be NULL.
* The pkt_type variable may be set to MQTT_INVALID, if the parsing
* stage is aborted before determining the MQTT msg packet type.
*
* @param [in] ctx MQTT context
* @param [in] pkt_type MQTT Packet type
*/
void (*malformed)(struct mqtt_ctx *ctx, uint16_t pkt_type);
/* Internal use only */
int (*rcv)(struct mqtt_ctx *ctx, struct net_buf *);
/** Application type, see: enum mqtt_app */
uint8_t app_type;
/* Clean session is also part of the MQTT CONNECT msg, however app
* behavior is influenced by this parameter, so we keep a copy here
*/
/** MQTT Clean Session parameter */
uint8_t clean_session:1;
/** 1 if the MQTT application is connected and 0 otherwise */
uint8_t connected:1;
};
/**
* Initializes the MQTT context structure
*
* @param ctx MQTT context structure
* @param app_type See enum mqtt_app
* @retval 0, always.
*/
int mqtt_init(struct mqtt_ctx *ctx, enum mqtt_app app_type);
/**
* Sends the MQTT CONNECT message
*
* @param [in] ctx MQTT context structure
* @param [in] msg MQTT CONNECT msg
*
* @retval 0 on success
* @retval -EIO
* @retval -ENOMEM
* @retval -EINVAL
*/
int mqtt_tx_connect(struct mqtt_ctx *ctx, struct mqtt_connect_msg *msg);
/**
* Send the MQTT DISCONNECT message
*
* @param [in] ctx MQTT context structure
*
* @retval 0 on success
* @retval -EIO
* @retval -ENOMEM
* @retval -EINVAL
*/
int mqtt_tx_disconnect(struct mqtt_ctx *ctx);
/**
* Sends the MQTT PUBACK message with the given packet id
*
* @param [in] ctx MQTT context structure
* @param [in] id MQTT Packet Identifier
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_puback(struct mqtt_ctx *ctx, uint16_t id);
/**
* Sends the MQTT PUBCOMP message with the given packet id
*
* @param [in] ctx MQTT context structure
* @param [in] id MQTT Packet Identifier
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_pubcomp(struct mqtt_ctx *ctx, uint16_t id);
/**
* Sends the MQTT PUBREC message with the given packet id
*
* @param [in] ctx MQTT context structure
* @param [in] id MQTT Packet Identifier
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_pubrec(struct mqtt_ctx *ctx, uint16_t id);
/**
* Sends the MQTT PUBREL message with the given packet id
*
* @param [in] ctx MQTT context structure
* @param [in] id MQTT Packet Identifier
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_pubrel(struct mqtt_ctx *ctx, uint16_t id);
/**
* Sends the MQTT PUBLISH message
*
* @param [in] ctx MQTT context structure
* @param [in] msg MQTT PUBLISH msg
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_publish(struct mqtt_ctx *ctx, struct mqtt_publish_msg *msg);
/**
* Sends the MQTT PINGREQ message
*
* @param [in] ctx MQTT context structure
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_pingreq(struct mqtt_ctx *ctx);
/**
* Sends the MQTT SUBSCRIBE message
*
* @param [in] ctx MQTT context structure
* @param [in] pkt_id Packet identifier for the MQTT SUBSCRIBE msg
* @param [in] items Number of elements in 'topics' and 'qos' arrays
* @param [in] topics Array of 'items' elements containing C strings.
* For example: {"sensors", "lights", "doors"}
* @param [in] qos Array of 'items' elements containing MQTT QoS values:
* MQTT_QoS0, MQTT_QoS1, MQTT_QoS2. For example for the 'topics'
* array above the following QoS may be used: {MQTT_QoS0,
* MQTT_QoS2, MQTT_QoS1}, indicating that the subscription to
* 'lights' must be done with MQTT_QoS2
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_subscribe(struct mqtt_ctx *ctx, uint16_t pkt_id, uint8_t items,
const char *topics[], const enum mqtt_qos qos[]);
/**
* Sends the MQTT UNSUBSCRIBE message
*
* @param [in] ctx MQTT context structure
* @param [in] pkt_id Packet identifier for the MQTT UNSUBSCRIBE msg
* @param [in] items Number of elements in the 'topics' array
* @param [in] topics Array of 'items' elements containing C strings
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
* @retval -EIO
*/
int mqtt_tx_unsubscribe(struct mqtt_ctx *ctx, uint16_t pkt_id, uint8_t items,
const char *topics[]);
/**
* Parses and validates the MQTT CONNACK msg
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
* @param [in] clean_session MQTT clean session parameter
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_connack(struct mqtt_ctx *ctx, struct net_buf *rx,
int clean_session);
/**
* Parses and validates the MQTT PUBACK message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_puback(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses and validates the MQTT PUBCOMP message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_pubcomp(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses and validates the MQTT PUBREC message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_pubrec(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses and validates the MQTT PUBREL message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_pubrel(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses the MQTT PINGRESP message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_pingresp(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses the MQTT SUBACK message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_suback(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses the MQTT UNSUBACK message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
*/
int mqtt_rx_unsuback(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* Parses the MQTT PUBLISH message
*
* @param [in] ctx MQTT context structure
* @param [in] rx Data buffer
*
* @retval 0 on success
* @retval -EINVAL
* @retval -ENOMEM
*/
int mqtt_rx_publish(struct mqtt_ctx *ctx, struct net_buf *rx);
/**
* @}
*/
#endif