/* net.h -- CoAP network interface * * Copyright (C) 2010--2013 Olaf Bergmann * * This file is part of the CoAP library libcoap. Please see * README for terms of use. */ #ifndef _COAP_NET_H_ #define _COAP_NET_H_ #ifdef __cplusplus extern "C" { #endif #include "coap_config.h" #include #include #include #include #include #include #include #include "option.h" #include "address.h" #include "prng.h" #include "pdu.h" #include "coap_time.h" struct coap_queue_t; typedef struct coap_queue_t { struct coap_queue_t *next; coap_tick_t t; /**< when to send PDU for the next time */ unsigned char retransmit_cnt; /**< retransmission counter, will be removed when zero */ unsigned int timeout; /**< the randomized timeout value */ coap_address_t local; /**< local address */ coap_address_t remote; /**< remote address */ coap_tid_t id; /**< unique transaction id */ coap_pdu_t *pdu; /**< the CoAP PDU to send */ } coap_queue_t; /** Adds node to given queue, ordered by node->t. */ int coap_insert_node(coap_queue_t **queue, coap_queue_t *node); /** Destroys specified node. */ int coap_delete_node(coap_queue_t *node); /** Removes all items from given queue and frees the allocated storage. */ void coap_delete_all(coap_queue_t *queue); /** Creates a new node suitable for adding to the CoAP sendqueue. */ coap_queue_t *coap_new_node(); struct coap_resource_t; struct coap_context_t; #ifndef WITHOUT_ASYNC struct coap_async_state_t; #endif /** Message handler that is used as call-back in coap_context_t */ typedef void (*coap_response_handler_t)(struct coap_context_t *, const coap_address_t *remote, coap_pdu_t *sent, coap_pdu_t *received, const coap_tid_t id); #define COAP_MID_CACHE_SIZE 3 typedef struct { unsigned char flags[COAP_MID_CACHE_SIZE]; coap_key_t item[COAP_MID_CACHE_SIZE]; } coap_mid_cache_t; /** The CoAP stack's global state is stored in a coap_context_t object */ typedef struct coap_context_t { coap_opt_filter_t known_options; struct coap_resource_t *resources; /**< hash table or list of known resources */ #ifndef WITHOUT_ASYNC /** list of asynchronous transactions */ struct coap_async_state_t *async_state; #endif /* WITHOUT_ASYNC */ /** * The time stamp in the first element of the sendqeue is relative * to sendqueue_basetime. */ coap_tick_t sendqueue_basetime; coap_queue_t *sendqueue, *recvqueue; int sockfd; /**< send/receive socket */ /** * The last message id that was used is stored in this field. The * initial value is set by coap_new_context() and is usually a * random value. A new message id can be created with * coap_new_message_id(). */ unsigned short message_id; /** * The next value to be used for Observe. This field is global for * all resources and will be updated when notifications are created. */ unsigned int observe; coap_response_handler_t response_handler; } coap_context_t; /** * Registers a new message handler that is called whenever a response * was received that matches an ongoing transaction. * * @param context The context to register the handler for. * @param handler The response handler to register. */ static inline void coap_register_response_handler(coap_context_t *context, coap_response_handler_t handler) { context->response_handler = handler; } /** * Registers the option type @p type with the given context object @p * ctx. * * @param ctx The context to use. * @param type The option type to register. */ inline static void coap_register_option(coap_context_t *ctx, unsigned char type) { coap_option_setb(ctx->known_options, type); } /** * Set sendqueue_basetime in the given context object @p ctx to @p * now. This function returns the number of elements in the queue * head that have timed out. */ unsigned int coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now); /** Returns the next pdu to send without removing from sendqeue. */ coap_queue_t *coap_peek_next(coap_context_t *context); /** Returns the next pdu to send and removes it from the sendqeue. */ coap_queue_t *coap_pop_next(coap_context_t *context); /** Creates a new coap_context_t object that will hold the CoAP stack status. */ coap_context_t *coap_new_context(const coap_address_t *listen_addr); /** * Returns a new message id and updates @p context->message_id * accordingly. The message id is returned in network byte order * to make it easier to read in tracing tools. * * @param context the current coap_context_t object * @return incremented message id in network byte order */ static inline unsigned short coap_new_message_id(coap_context_t *context) { return htons(++(context->message_id)); } /* CoAP stack context must be released with coap_free_context() */ void coap_free_context(coap_context_t *context); /** * Sends a confirmed CoAP message to given destination. The memory * that is allocated by pdu will not be released by * coap_send_confirmed(). The caller must release the memory. * * @param context The CoAP context to use. * @param dst The address to send to. * @param pdu The CoAP PDU to send. * @return The message id of the sent message or @c COAP_INVALID_TID on error. */ coap_tid_t coap_send_confirmed(coap_context_t *context, const coap_address_t *dst, coap_pdu_t *pdu); /** * Creates a new ACK PDU with specified error @p code. The options * specified by the filter expression @p opts will be copied from the * original request contained in @p request. Unless @c * SHORT_ERROR_RESPONSE was defined at build time, the textual reason * phrase for @p code will be added as payload, with Content-Type @c * 0. This function returns a pointer to the new response message, or * @c NULL on error. The storage allocated for the new message must be * relased with coap_free(). * * @param request Specification of the received (confirmable) request. * @param code The error code to set. * @param opts An option filter that specifies which options to copy * from the original request in @p node. * * @return A pointer to the new message or @c NULL on error. */ coap_pdu_t *coap_new_error_response(coap_pdu_t *request, unsigned char code, coap_opt_filter_t opts); /** * Sends a non-confirmed CoAP message to given destination. The memory * that is allocated by pdu will not be released by coap_send(). * The caller must release the memory. * * @param context The CoAP context to use. * @param dst The address to send to. * @param pdu The CoAP PDU to send. * @return The message id of the sent message or @c COAP_INVALID_TID on error. */ coap_tid_t coap_send(coap_context_t *context, const coap_address_t *dst, coap_pdu_t *pdu); /** * Sends an error response with code @p code for request @p request to * @p dst. @p opts will be passed to coap_new_error_response() to * copy marked options from the request. This function returns the * transaction id if the message was sent, or @c COAP_INVALID_TID * otherwise. * * @param context The context to use. * @param request The original request to respond to. * @param dst The remote peer that sent the request. * @param code The reponse code. * @param opts A filter that specifies the options to copy from the * @p request. * * @return The transaction id if the message was sent, or @c * COAP_INVALID_TID otherwise. */ coap_tid_t coap_send_error(coap_context_t *context, coap_pdu_t *request, const coap_address_t *dst, unsigned char code, coap_opt_filter_t opts); /** * Helper funktion to create and send a message with @p type (usually * ACK or RST). This function returns @c COAP_INVALID_TID when the * message was not sent, a valid transaction id otherwise. * * @param context The CoAP context. * @param dst Where to send the context. * @param request The request that should be responded to. * @param type Which type to set * @return transaction id on success or @c COAP_INVALID_TID otherwise. */ coap_tid_t coap_send_message_type(coap_context_t *context, const coap_address_t *dst, coap_pdu_t *request, unsigned char type); /** * Sends an ACK message with code @c 0 for the specified @p request to * @p dst. This function returns the corresponding transaction id if * the message was sent or @c COAP_INVALID_TID on error. * * @param context The context to use. * @param dst The destination address. * @param request The request to be acknowledged. * * @return The transaction id if ACK was sent or @c COAP_INVALID_TID * on error. */ coap_tid_t coap_send_ack(coap_context_t *context, const coap_address_t *dst, coap_pdu_t *request); /** * Sends an RST message with code @c 0 for the specified @p request to * @p dst. This function returns the corresponding transaction id if * the message was sent or @c COAP_INVALID_TID on error. * * @param context The context to use. * @param dst The destination address. * @param request The request to be reset. * * @return The transaction id if RST was sent or @c COAP_INVALID_TID * on error. */ static inline coap_tid_t coap_send_rst(coap_context_t *context, const coap_address_t *dst, coap_pdu_t *request) { return coap_send_message_type(context, dst, request, COAP_MESSAGE_RST); } /** Handles retransmissions of confirmable messages */ coap_tid_t coap_retransmit(coap_context_t *context, coap_queue_t *node); /** * Reads data from the network and tries to parse as CoAP PDU. On success, 0 is returned * and a new node with the parsed PDU is added to the receive queue in the specified context * object. */ int coap_read(coap_context_t *context); /** * Calculates a unique transaction id from given arguments @p peer and * @p pdu. The id is returned in @p id. * * @param peer The remote party who sent @p pdu. * @param pdu The message that initiated the transaction. * @param id Set to the new id. */ void coap_transaction_id(const coap_address_t *peer, const coap_pdu_t *pdu, coap_tid_t *id); /** * This function removes the element with given @p id from the list * given list. If @p id was found, @p node is updated to point to the * removed element. Note that the storage allocated by @p node is * @b not released. The caller must do this manually using * coap_delete_node(). This function returns @c 1 if the element with * id @p id was found, @c 0 otherwise. For a return value of @c 0, * the contents of @p node is undefined. * * @param queue The queue to search for @p id. * @param id The node id to look for. * @param node If found, @p node is updated to point to the * removed node. You must release the storage pointed to by * @p node manually. * * @return @c 1 if @p id was found, @c 0 otherwise. */ int coap_remove_from_queue(coap_queue_t **queue, coap_tid_t id, coap_queue_t **node); /** * Removes the transaction identified by @p id from given @p queue. * This is a convenience function for coap_remove_from_queue() with * automatic deletion of the removed node. * * @param queue The queue to search for @p id. * @param id The transaction id. * * @return @c 1 if node was found, removed and destroyed, @c 0 otherwise. */ inline static int coap_remove_transaction(coap_queue_t **queue, coap_tid_t id) { coap_queue_t *node; if (!coap_remove_from_queue(queue, id, &node)) { return 0; } coap_delete_node(node); return 1; } /** * Retrieves transaction from queue. * @queue The transaction queue to be searched * @id Unique key of the transaction to find. * @return A pointer to the transaction object or NULL if not found */ coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_tid_t id); /** * Cancels all outstanding messages for peer @p dst that have the * specified token. * * @param context The context in use * @param dst Destination address of the messages to remove. * @param token Message token * @param token_length Actual length of @p token */ void coap_cancel_all_messages(coap_context_t *context, const coap_address_t *dst, const unsigned char *token, size_t token_length); /** Dispatches the PDUs from the receive queue in given context. */ void coap_dispatch(coap_context_t *context); /** Returns 1 if there are no messages to send or to dispatch in the context's queues. */ int coap_can_exit(coap_context_t *context); /** * Returns the current value of an internal tick counter. The counter * counts \c COAP_TICKS_PER_SECOND ticks every second. */ void coap_ticks(coap_tick_t *); /** * Verifies that @p pdu contains no unknown critical options. Options * must be registered at @p ctx, using the function * coap_register_option(). A basic set of options is registered * automatically by coap_new_context(). This function returns @c 1 if * @p pdu is ok, @c 0 otherwise. The given filter object @p unknown * will be updated with the unknown options. As only @c COAP_MAX_OPT * options can be signalled this way, remaining options must be * examined manually. * * @code coap_opt_filter_t f = COAP_OPT_NONE; coap_opt_iterator_t opt_iter; if (coap_option_check_critical(ctx, pdu, f) == 0) { coap_option_iterator_init(pdu, &opt_iter, f); while (coap_option_next(&opt_iter)) { if (opt_iter.type & 0x01) { ... 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); int coap_readfrom(coap_context_t *ctx, void *buf, size_t bytes_read, struct sockaddr *from, socklen_t fromlen); void coap_with_dtls(void *priv); #ifdef __cplusplus } #endif #endif /* _COAP_NET_H_ */