2021-04-14 18:10:05 +03:00

78 lines
2.4 KiB
C

/*
* subscribe.h -- subscription handling for CoAP
* see RFC7641
*
* Copyright (C) 2010-2012,2014-2015 Olaf Bergmann <bergmann@tzi.org>
*
* This file is part of the CoAP library libcoap. Please see README for terms
* of use.
*/
#ifndef COAP_SUBSCRIBE_H_
#define COAP_SUBSCRIBE_H_
#include "address.h"
#include "coap_io.h"
#include "block.h"
/**
* @defgroup observe Resource observation
* API functions for interfacing with the observe handling (RFC7641)
* @{
*/
/**
* The value COAP_OBSERVE_ESTABLISH in a GET request indicates a new observe
* relationship for (sender address, token) is requested.
*/
#define COAP_OBSERVE_ESTABLISH 0
/**
* The value COAP_OBSERVE_CANCEL in a GET request indicates that the observe
* relationship for (sender address, token) must be cancelled.
*/
#define COAP_OBSERVE_CANCEL 1
#ifndef COAP_OBS_MAX_NON
/**
* Number of notifications that may be sent non-confirmable before a confirmable
* message is sent to detect if observers are alive. The maximum allowed value
* here is @c 15.
*/
#define COAP_OBS_MAX_NON 5
#endif /* COAP_OBS_MAX_NON */
#ifndef COAP_OBS_MAX_FAIL
/**
* Number of confirmable notifications that may fail (i.e. time out without
* being ACKed) before an observer is removed. The maximum value for
* COAP_OBS_MAX_FAIL is @c 3.
*/
#define COAP_OBS_MAX_FAIL 3
#endif /* COAP_OBS_MAX_FAIL */
/** Subscriber information */
typedef struct coap_subscription_t {
struct coap_subscription_t *next; /**< next element in linked list */
coap_session_t *session; /**< subscriber session */
unsigned int non_cnt:4; /**< up to 15 non-confirmable notifies allowed */
unsigned int fail_cnt:2; /**< up to 3 confirmable notifies can fail */
unsigned int dirty:1; /**< set if the notification temporarily could not be
* sent (in that case, the resource's partially
* dirty flag is set too) */
unsigned int has_block2:1; /**< GET request had Block2 definition */
uint16_t tid; /**< transaction id, if any, in regular host byte order */
coap_block_t block2; /**< GET request Block2 definition */
size_t token_length; /**< actual length of token */
unsigned char token[8]; /**< token used for subscription */
coap_string_t *query; /**< query string used for subscription, if any */
} coap_subscription_t;
void coap_subscription_init(coap_subscription_t *);
/** @} */
#endif /* COAP_SUBSCRIBE_H_ */