522 lines
18 KiB
C
522 lines
18 KiB
C
/*
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* net.h -- CoAP network interface
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*
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* Copyright (C) 2010-2015 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_NET_H_
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#define _COAP_NET_H_
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/time.h>
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#include <time.h>
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#ifdef WITH_LWIP
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#include <lwip/ip_addr.h>
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#endif
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#include "coap_io.h"
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#include "coap_time.h"
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#include "option.h"
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#include "pdu.h"
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#include "prng.h"
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struct coap_queue_t;
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typedef struct coap_queue_t {
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struct coap_queue_t *next;
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coap_tick_t t; /**< when to send PDU for the next time */
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unsigned char retransmit_cnt; /**< retransmission counter, will be removed
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* when zero */
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unsigned int timeout; /**< the randomized timeout value */
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coap_endpoint_t local_if; /**< the local address interface */
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coap_address_t remote; /**< remote address */
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coap_tid_t id; /**< unique transaction id */
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coap_pdu_t *pdu; /**< the CoAP PDU to send */
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} coap_queue_t;
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/** Adds node to given queue, ordered by node->t. */
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int coap_insert_node(coap_queue_t **queue, coap_queue_t *node);
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/** Destroys specified node. */
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int coap_delete_node(coap_queue_t *node);
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/** Removes all items from given queue and frees the allocated storage. */
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void coap_delete_all(coap_queue_t *queue);
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/** Creates a new node suitable for adding to the CoAP sendqueue. */
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coap_queue_t *coap_new_node(void);
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struct coap_resource_t;
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struct coap_context_t;
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#ifndef WITHOUT_ASYNC
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struct coap_async_state_t;
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#endif
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/** Message handler that is used as call-back in coap_context_t */
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typedef void (*coap_response_handler_t)(struct coap_context_t *,
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const coap_endpoint_t *local_interface,
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const coap_address_t *remote,
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coap_pdu_t *sent,
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coap_pdu_t *received,
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const coap_tid_t id);
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#define COAP_MID_CACHE_SIZE 3
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typedef struct {
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unsigned char flags[COAP_MID_CACHE_SIZE];
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coap_key_t item[COAP_MID_CACHE_SIZE];
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} coap_mid_cache_t;
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/** The CoAP stack's global state is stored in a coap_context_t object */
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typedef struct coap_context_t {
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coap_opt_filter_t known_options;
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struct coap_resource_t *resources; /**< hash table or list of known resources */
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#ifndef WITHOUT_ASYNC
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/**
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* list of asynchronous transactions */
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struct coap_async_state_t *async_state;
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#endif /* WITHOUT_ASYNC */
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/**
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* The time stamp in the first element of the sendqeue is relative
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* to sendqueue_basetime. */
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coap_tick_t sendqueue_basetime;
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coap_queue_t *sendqueue;
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coap_endpoint_t *endpoint; /**< the endpoint used for listening */
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#ifdef WITH_POSIX
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int sockfd; /**< send/receive socket */
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#endif /* WITH_POSIX */
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#ifdef WITH_CONTIKI
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struct uip_udp_conn *conn; /**< uIP connection object */
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struct etimer retransmit_timer; /**< fires when the next packet must be sent */
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struct etimer notify_timer; /**< used to check resources periodically */
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#endif /* WITH_CONTIKI */
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#ifdef WITH_LWIP
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uint8_t timer_configured; /**< Set to 1 when a retransmission is
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* scheduled using lwIP timers for this
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* context, otherwise 0. */
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#endif /* WITH_LWIP */
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/**
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* The last message id that was used is stored in this field. The initial
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* value is set by coap_new_context() and is usually a random value. A new
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* message id can be created with coap_new_message_id().
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*/
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unsigned short message_id;
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/**
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* The next value to be used for Observe. This field is global for all
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* resources and will be updated when notifications are created.
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*/
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unsigned int observe;
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coap_response_handler_t response_handler;
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ssize_t (*network_send)(struct coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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unsigned char *data, size_t datalen);
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ssize_t (*network_read)(coap_endpoint_t *ep, coap_packet_t **packet);
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} coap_context_t;
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/**
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* Registers a new message handler that is called whenever a response was
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* received that matches an ongoing transaction.
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*
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* @param context The context to register the handler for.
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* @param handler The response handler to register.
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*/
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static inline void
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coap_register_response_handler(coap_context_t *context,
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coap_response_handler_t handler) {
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context->response_handler = handler;
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}
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/**
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* Registers the option type @p type with the given context object @p ctx.
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*
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* @param ctx The context to use.
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* @param type The option type to register.
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*/
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inline static void
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coap_register_option(coap_context_t *ctx, unsigned char type) {
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coap_option_setb(ctx->known_options, type);
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}
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/**
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* Set sendqueue_basetime in the given context object @p ctx to @p now. This
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* function returns the number of elements in the queue head that have timed
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* out.
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*/
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unsigned int coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now);
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/**
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* Returns the next pdu to send without removing from sendqeue.
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*/
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coap_queue_t *coap_peek_next( coap_context_t *context );
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/**
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* Returns the next pdu to send and removes it from the sendqeue.
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*/
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coap_queue_t *coap_pop_next( coap_context_t *context );
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/**
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* Creates a new coap_context_t object that will hold the CoAP stack status.
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*/
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coap_context_t *coap_new_context(const coap_address_t *listen_addr);
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/**
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* Returns a new message id and updates @p context->message_id accordingly. The
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* message id is returned in network byte order to make it easier to read in
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* tracing tools.
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*
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* @param context The current coap_context_t object.
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*
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* @return Incremented message id in network byte order.
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*/
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static inline unsigned short
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coap_new_message_id(coap_context_t *context) {
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context->message_id++;
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#ifndef WITH_CONTIKI
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return htons(context->message_id);
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#else /* WITH_CONTIKI */
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return uip_htons(context->message_id);
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#endif
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}
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/**
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* CoAP stack context must be released with coap_free_context(). This function
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* clears all entries from the receive queue and send queue and deletes the
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* resources that have been registered with @p context, and frees the attached
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* endpoints.
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*/
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void coap_free_context(coap_context_t *context);
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/**
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* Sends a confirmed CoAP message to given destination. The memory that is
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* allocated by pdu will not be released by coap_send_confirmed(). The caller
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* must release the memory.
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*
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* @param context The CoAP context to use.
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* @param local_interface The local network interface where the outbound
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* packet is sent.
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* @param dst The address to send to.
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* @param pdu The CoAP PDU to send.
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*
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* @return The message id of the sent message or @c
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* COAP_INVALID_TID on error.
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*/
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coap_tid_t coap_send_confirmed(coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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coap_pdu_t *pdu);
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/**
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* Creates a new ACK PDU with specified error @p code. The options specified by
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* the filter expression @p opts will be copied from the original request
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* contained in @p request. Unless @c SHORT_ERROR_RESPONSE was defined at build
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* time, the textual reason phrase for @p code will be added as payload, with
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* Content-Type @c 0.
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* This function returns a pointer to the new response message, or @c NULL on
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* error. The storage allocated for the new message must be relased with
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* coap_free().
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*
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* @param request Specification of the received (confirmable) request.
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* @param code The error code to set.
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* @param opts An option filter that specifies which options to copy from
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* the original request in @p node.
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*
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* @return A pointer to the new message or @c NULL on error.
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*/
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coap_pdu_t *coap_new_error_response(coap_pdu_t *request,
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unsigned char code,
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coap_opt_filter_t opts);
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/**
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* Sends a non-confirmed CoAP message to given destination. The memory that is
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* allocated by pdu will not be released by coap_send().
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* The caller must release the memory.
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*
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* @param context The CoAP context to use.
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* @param local_interface The local network interface where the outbound packet
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* is sent.
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* @param dst The address to send to.
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* @param pdu The CoAP PDU to send.
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*
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* @return The message id of the sent message or @c
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* COAP_INVALID_TID on error.
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*/
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coap_tid_t coap_send(coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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coap_pdu_t *pdu);
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/**
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* Sends an error response with code @p code for request @p request to @p dst.
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* @p opts will be passed to coap_new_error_response() to copy marked options
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* from the request. This function returns the transaction id if the message was
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* sent, or @c COAP_INVALID_TID otherwise.
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*
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* @param context The context to use.
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* @param request The original request to respond to.
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* @param local_interface The local network interface where the outbound packet
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* is sent.
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* @param dst The remote peer that sent the request.
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* @param code The response code.
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* @param opts A filter that specifies the options to copy from the
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* @p request.
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*
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* @return The transaction id if the message was sent, or @c
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* COAP_INVALID_TID otherwise.
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*/
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coap_tid_t coap_send_error(coap_context_t *context,
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coap_pdu_t *request,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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unsigned char code,
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coap_opt_filter_t opts);
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/**
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* Helper funktion to create and send a message with @p type (usually ACK or
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* RST). This function returns @c COAP_INVALID_TID when the message was not
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* sent, a valid transaction id otherwise.
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*
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* @param context The CoAP context.
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* @param local_interface The local network interface where the outbound packet
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* is sent.
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* @param dst Where to send the context.
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* @param request The request that should be responded to.
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* @param type Which type to set.
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* @return transaction id on success or @c COAP_INVALID_TID
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* otherwise.
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*/
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coap_tid_t
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coap_send_message_type(coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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coap_pdu_t *request,
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unsigned char type);
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/**
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* Sends an ACK message with code @c 0 for the specified @p request to @p dst.
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* This function returns the corresponding transaction id if the message was
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* sent or @c COAP_INVALID_TID on error.
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*
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* @param context The context to use.
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* @param local_interface The local network interface where the outbound packet
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* is sent.
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* @param dst The destination address.
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* @param request The request to be acknowledged.
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*
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* @return The transaction id if ACK was sent or @c
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* COAP_INVALID_TID on error.
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*/
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coap_tid_t coap_send_ack(coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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coap_pdu_t *request);
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/**
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* Sends an RST message with code @c 0 for the specified @p request to @p dst.
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* This function returns the corresponding transaction id if the message was
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* sent or @c COAP_INVALID_TID on error.
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*
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* @param context The context to use.
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* @param local_interface The local network interface where the outbound packet
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* is sent.
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* @param dst The destination address.
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* @param request The request to be reset.
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*
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* @return The transaction id if RST was sent or @c
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* COAP_INVALID_TID on error.
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*/
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static inline coap_tid_t
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coap_send_rst(coap_context_t *context,
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const coap_endpoint_t *local_interface,
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const coap_address_t *dst,
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coap_pdu_t *request) {
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return coap_send_message_type(context,
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local_interface,
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dst, request,
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COAP_MESSAGE_RST);
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}
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/**
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* Handles retransmissions of confirmable messages
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*/
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coap_tid_t coap_retransmit(coap_context_t *context, coap_queue_t *node);
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/**
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* Reads data from the network and tries to parse as CoAP PDU. On success, 0 is
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* returned and a new node with the parsed PDU is added to the receive queue in
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* the specified context object.
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*/
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int coap_read(coap_context_t *context);
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/**
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* Parses and interprets a CoAP message with context @p ctx. This function
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* returns @c 0 if the message was handled, or a value less than zero on
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* error.
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*
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* @param ctx The current CoAP context.
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* @param packet The received packet.
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*
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* @return @c 0 if message was handled successfully, or less than zero on
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* error.
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*/
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int coap_handle_message(coap_context_t *ctx,
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coap_packet_t *packet);
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/**
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* Calculates a unique transaction id from given arguments @p peer and @p pdu.
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* The id is returned in @p id.
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*
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* @param peer The remote party who sent @p pdu.
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* @param pdu The message that initiated the transaction.
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* @param id Set to the new id.
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*/
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void coap_transaction_id(const coap_address_t *peer,
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const coap_pdu_t *pdu,
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coap_tid_t *id);
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/**
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* This function removes the element with given @p id from the list given list.
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* If @p id was found, @p node is updated to point to the removed element. Note
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* that the storage allocated by @p node is @b not released. The caller must do
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* this manually using coap_delete_node(). This function returns @c 1 if the
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* element with id @p id was found, @c 0 otherwise. For a return value of @c 0,
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* the contents of @p node is undefined.
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*
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* @param queue The queue to search for @p id.
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* @param id The node id to look for.
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* @param node If found, @p node is updated to point to the removed node. You
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* must release the storage pointed to by @p node manually.
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*
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* @return @c 1 if @p id was found, @c 0 otherwise.
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*/
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int coap_remove_from_queue(coap_queue_t **queue,
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coap_tid_t id,
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coap_queue_t **node);
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/**
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* Removes the transaction identified by @p id from given @p queue. This is a
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* convenience function for coap_remove_from_queue() with automatic deletion of
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* the removed node.
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*
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* @param queue The queue to search for @p id.
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* @param id The transaction id.
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*
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* @return @c 1 if node was found, removed and destroyed, @c 0 otherwise.
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*/
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inline static int
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coap_remove_transaction(coap_queue_t **queue, coap_tid_t id) {
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coap_queue_t *node;
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if (!coap_remove_from_queue(queue, id, &node))
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return 0;
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coap_delete_node(node);
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return 1;
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}
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/**
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* Retrieves transaction from the queue.
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*
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* @param queue The transaction queue to be searched.
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* @param id Unique key of the transaction to find.
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*
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* @return A pointer to the transaction object or NULL if not found.
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*/
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coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_tid_t id);
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/**
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* Cancels all outstanding messages for peer @p dst that have the specified
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* token.
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*
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* @param context The context in use.
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* @param dst Destination address of the messages to remove.
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* @param token Message token.
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* @param token_length Actual length of @p token.
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*/
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void coap_cancel_all_messages(coap_context_t *context,
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const coap_address_t *dst,
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const unsigned char *token,
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size_t token_length);
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/**
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* Dispatches the PDUs from the receive queue in given context.
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*/
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void coap_dispatch(coap_context_t *context, coap_queue_t *rcvd);
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/**
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* Returns 1 if there are no messages to send or to dispatch in the context's
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* queues. */
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int coap_can_exit(coap_context_t *context);
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/**
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* Returns the current value of an internal tick counter. The counter counts \c
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* COAP_TICKS_PER_SECOND ticks every second.
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*/
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void coap_ticks(coap_tick_t *);
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/**
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* Verifies that @p pdu contains no unknown critical options. Options must be
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* registered at @p ctx, using the function coap_register_option(). A basic set
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* of options is registered automatically by coap_new_context(). This function
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* returns @c 1 if @p pdu is ok, @c 0 otherwise. The given filter object @p
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* unknown will be updated with the unknown options. As only @c COAP_MAX_OPT
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* options can be signalled this way, remaining options must be examined
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* manually.
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*
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* @code
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coap_opt_filter_t f = COAP_OPT_NONE;
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coap_opt_iterator_t opt_iter;
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if (coap_option_check_critical(ctx, pdu, f) == 0) {
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coap_option_iterator_init(pdu, &opt_iter, f);
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while (coap_option_next(&opt_iter)) {
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if (opt_iter.type & 0x01) {
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|
... handle unknown critical option in opt_iter ...
|
|
}
|
|
}
|
|
}
|
|
* @endcode
|
|
*
|
|
* @param ctx The context where all known options are registered.
|
|
* @param pdu The PDU to check.
|
|
* @param unknown The output filter that will be updated to indicate the
|
|
* unknown critical options found in @p pdu.
|
|
*
|
|
* @return @c 1 if everything was ok, @c 0 otherwise.
|
|
*/
|
|
int coap_option_check_critical(coap_context_t *ctx,
|
|
coap_pdu_t *pdu,
|
|
coap_opt_filter_t unknown);
|
|
|
|
/**
|
|
* Creates a new response for given @p request with the contents of @c
|
|
* .well-known/core. The result is NULL on error or a newly allocated PDU that
|
|
* must be released by coap_delete_pdu().
|
|
*
|
|
* @param context The current coap context to use.
|
|
* @param request The request for @c .well-known/core .
|
|
*
|
|
* @return A new 2.05 response for @c .well-known/core or NULL on error.
|
|
*/
|
|
coap_pdu_t *coap_wellknown_response(coap_context_t *context,
|
|
coap_pdu_t *request);
|
|
|
|
#endif /* _COAP_NET_H_ */
|