/*
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* subscribe.h -- subscription handling for CoAP
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* see draft-ietf-core-observe-16
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*
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* Copyright (C) 2010-2012,2014-2015 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see README for terms
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* of use.
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*/
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#ifndef _COAP_SUBSCRIBE_H_
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#define _COAP_SUBSCRIBE_H_
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#include "address.h"
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#include "coap_io.h"
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/**
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* @defgroup observe Resource observation
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* @{
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*/
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/**
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* The value COAP_OBSERVE_ESTABLISH in a GET request indicates a new observe
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* relationship for (sender address, token) is requested.
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*/
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#define COAP_OBSERVE_ESTABLISH 0
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/**
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* The value COAP_OBSERVE_CANCEL in a GET request indicates that the observe
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* relationship for (sender address, token) must be cancelled.
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*/
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#define COAP_OBSERVE_CANCEL 1
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#ifndef COAP_OBS_MAX_NON
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/**
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* Number of notifications that may be sent non-confirmable before a confirmable
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* message is sent to detect if observers are alive. The maximum allowed value
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* here is @c 15.
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*/
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#define COAP_OBS_MAX_NON 5
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#endif /* COAP_OBS_MAX_NON */
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#ifndef COAP_OBS_MAX_FAIL
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/**
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* Number of confirmable notifications that may fail (i.e. time out without
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* being ACKed) before an observer is removed. The maximum value for
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* COAP_OBS_MAX_FAIL is @c 3.
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*/
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#define COAP_OBS_MAX_FAIL 3
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#endif /* COAP_OBS_MAX_FAIL */
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/** Subscriber information */
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typedef struct coap_subscription_t {
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struct coap_subscription_t *next; /**< next element in linked list */
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coap_endpoint_t local_if; /**< local communication interface */
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coap_address_t subscriber; /**< address and port of subscriber */
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unsigned int non_cnt:4; /**< up to 15 non-confirmable notifies allowed */
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unsigned int fail_cnt:2; /**< up to 3 confirmable notifies can fail */
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unsigned int dirty:1; /**< set if the notification temporarily could not be
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* sent (in that case, the resource's partially
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* dirty flag is set too) */
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size_t token_length; /**< actual length of token */
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unsigned char token[8]; /**< token used for subscription */
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} coap_subscription_t;
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void coap_subscription_init(coap_subscription_t *);
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/** @} */
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#endif /* _COAP_SUBSCRIBE_H_ */
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