mqtt.h File Reference

Protos for MQTT handling. More...

`#include <MQTTClient.h>`
`#include <glib.h>`

Go to the source code of this file.

## Macros

#define | AUTH_MQTT 1

## Functions

int | mqtt_init (const char *)
| Init MQTT communication.
int | mqtt_init_auth (const char *, const char *, const char *)
| Init MQTT communication.
gboolean | mqtt_is_initialized (void)
| Get the global init status.
void | mqtt_reset (void)
| Destroy MQTTClient handle and free mqtt_t.
int | mqtt_publish (const char *, const char *)
| Publish a message on topic using the global client.
int | mqtt_publish_single_message_auth (const char *, const char *, const char *, const char *, const char *)
| Send a single message with credentials.
int | mqtt_publish_single_message (const char *, const char *, const char *)
| Send a single message.
int | mqtt_subscribe (const char *)
| subscribes to a single topic.
int | mqtt_retrieve_message (char **, int *, char **, int *, const unsigned int)
| wait for a given timeout in ms to retrieve any message of subscribed topics
int | mqtt_unsubscribe (const char *)
| unsubscribe a single topic.

## Detailed Description

Protos for MQTT handling.

## Macro Definition Documentation

## AUTH_MQTT

#define AUTH_MQTT 1

## Function Documentation

## mqtt_init()

int mqtt_init | ( | const char * | server_uri | ) |

Init MQTT communication.

Parameters

  server_uri | Server URI

Returns
  0 on success, <0 on error.

## mqtt_init_auth()

int mqtt_init_auth | ( | const char * | server_uri,
|  | const char * | username,
|  | const char * | password
| ) |  |

Init MQTT communication.

Parameters

  server_uri | Server URI
  username | Username
  password | Password

Returns
  0 on success, <0 on error.

## mqtt_is_initialized()

gboolean mqtt_is_initialized | ( | void |  | ) |

Get the global init status.

Returns
  Initialization status of mqtt handling.

## mqtt_publish()

int mqtt_publish | ( | const char * | topic,
|  | const char * | msg
| ) |  |

Publish a message on topic using the global client.

Parameters

  topic | topic
  msg | message

Returns
  0 on success, <0 on error.

## mqtt_publish_single_message()

int mqtt_publish_single_message | ( | const char * | server_uri_in,
|  | const char * | topic,
|  | const char * | msg
| ) |  |

Send a single message.

This functions creates a mqtt handle, connects, sends the message, closes the connection and destroys the handler. This function should not be chosen for repeated and frequent messaging. Its meant for error messages and the likes emitted by openvas.

Parameters

  server_uri_in | Server URI
  topic | Topic to publish to
  msg | Message to publish

Returns
  0 on success, <0 on failure.

## mqtt_publish_single_message_auth()

int mqtt_publish_single_message_auth | ( | const char * | server_uri_in,
|  | const char * | username_in,
|  | const char * | passwd_in,
|  | const char * | topic,
|  | const char * | msg
| ) |  |

Send a single message with credentials.

This functions creates a mqtt handle, connects, sends the message, closes the connection and destroys the handler. This function should not be chosen for repeated and frequent messaging. Its meant for error messages and the likes emitted by openvas.

Parameters

  server_uri_in | Server URI
  username_in | Username
  passwd_in | Password
  topic | Topic to publish to
  msg | Message to publish

Returns
  0 on success, <0 on failure.

## mqtt_reset()

void mqtt_reset | ( | void |  | ) |

Destroy MQTTClient handle and free mqtt_t.

## mqtt_retrieve_message()

int mqtt_retrieve_message | ( | char ** | topic,
|  | int * | topic_len,
|  | char ** | payload,
|  | int * | payload_len,
|  | const unsigned int | timeout
| ) |  |

wait for a given timeout in ms to retrieve any message of subscribed topics

This function performs a synchronous receive of incoming messages. Using this function allows a single-threaded client subscriber application to be written. When called, this function blocks until the next message arrives or the specified timeout expires.

Important note: The application must free() the memory allocated to the topic and payload when processing is complete.

Parameters

  [out] | topic | The address of a pointer to a topic. This function allocates the memory for the topic and returns it to the application by setting topic to point to the topic.
  [out] | topic_len | The length of the topic.
  [out] | payload | The address of a pointer to the received message. This function allocates the memory for the payload and returns it to the application by setting payload to point to the received message. The pointer is set to NULL if the timeout expires.
  [out] | payload_len | The length of the payload.
  | timeout | The length of time to wait for a message in milliseconds.

Returns
  0 on message retrieved, 1 on timeout and -1 on an error.

## mqtt_subscribe()

int mqtt_subscribe | ( | const char * | topic | ) |

subscribes to a single topic.

mqtt_subscribe uses global mqtt_t to subscribe with global qos to given topic.

To be able to subscribe to a topic the client needs to be connected to a broker. To do that call `mqtt_init` before `mqtt_subscribe`.

Parameters

  topic | Topic to subscribe to

Returns
  0 on success, -1 when mqtt is not initialized, -2 when subscription failed.

## mqtt_unsubscribe()

int mqtt_unsubscribe | ( | const char * | topic | ) |

unsubscribe a single topic.

This function unsubscribes global client from a given topic.

Parameters

  topic | Topic to unsubscribe from

Returns
  0 on success, -1 when given mqtt is not useable, -2 when unsubscribe failed.