/* * net.h -- CoAP network interface * * Copyright (C) 2010-2015 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_ #include #include #include #ifndef _WIN32 #include #endif #include #ifdef WITH_LWIP #include #endif #include "coap_io.h" #include "coap_dtls.h" #include "coap_event.h" #include "coap_time.h" #include "option.h" #include "pdu.h" #include "prng.h" #include "coap_session.h" struct coap_queue_t; /** * Queue entry */ 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_session_t *session; /**< the CoAP session */ coap_tid_t id; /**< CoAP transaction id */ coap_pdu_t *pdu; /**< the CoAP PDU to send */ } coap_queue_t; /** * Adds @p node to given @p queue, ordered by variable t in @p node. * * @param queue Queue to add to. * @param node Node entry to add to Queue. * * @return @c 1 added to queue, @c 0 failure. */ int coap_insert_node(coap_queue_t **queue, coap_queue_t *node); /** * Destroys specified @p node. * * @param node Node entry to remove. * * @return @c 1 node deleted from queue, @c 0 failure. */ int coap_delete_node(coap_queue_t *node); /** * Removes all items from given @p queue and frees the allocated storage. * * @param queue The queue to delete. */ void coap_delete_all(coap_queue_t *queue); /** * Creates a new node suitable for adding to the CoAP sendqueue. * * @return New node entry, or @c NULL if failure. */ coap_queue_t *coap_new_node(void); struct coap_resource_t; struct coap_context_t; #ifndef WITHOUT_ASYNC struct coap_async_state_t; #endif /** * Response handler that is used as call-back in coap_context_t. * * @param context CoAP session. * @param session CoAP session. * @param sent The PDU that was transmitted. * @param received The PDU that was received. * @param id CoAP transaction ID. */ typedef void (*coap_response_handler_t)(struct coap_context_t *context, coap_session_t *session, coap_pdu_t *sent, coap_pdu_t *received, const coap_tid_t id); /** * Negative Acknowedge handler that is used as call-back in coap_context_t. * * @param context CoAP session. * @param session CoAP session. * @param sent The PDU that was transmitted. * @param reason The reason for the NACK. * @param id CoAP transaction ID. */ typedef void (*coap_nack_handler_t)(struct coap_context_t *context, coap_session_t *session, coap_pdu_t *sent, coap_nack_reason_t reason, const coap_tid_t id); /** * Recieved Ping handler that is used as call-back in coap_context_t. * * @param context CoAP session. * @param session CoAP session. * @param received The PDU that was received. * @param id CoAP transaction ID. */ typedef void (*coap_ping_handler_t)(struct coap_context_t *context, coap_session_t *session, coap_pdu_t *received, const coap_tid_t id); /** * Recieved Pong handler that is used as call-back in coap_context_t. * * @param context CoAP session. * @param session CoAP session. * @param received The PDU that was received. * @param id CoAP transaction ID. */ typedef void (*coap_pong_handler_t)(struct coap_context_t *context, coap_session_t *session, coap_pdu_t *received, const coap_tid_t id); /** * 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 */ struct coap_resource_t *unknown_resource; /**< can be used for handling unknown 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; coap_endpoint_t *endpoint; /**< the endpoints used for listening */ coap_session_t *sessions; /**< client sessions */ #ifdef WITH_CONTIKI struct uip_udp_conn *conn; /**< uIP connection object */ struct etimer retransmit_timer; /**< fires when the next packet must be sent */ struct etimer notify_timer; /**< used to check resources periodically */ #endif /* WITH_CONTIKI */ #ifdef WITH_LWIP uint8_t timer_configured; /**< Set to 1 when a retransmission is * scheduled using lwIP timers for this * context, otherwise 0. */ #endif /* WITH_LWIP */ /** * 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(). */ uint16_t message_id; coap_response_handler_t response_handler; coap_nack_handler_t nack_handler; coap_ping_handler_t ping_handler; coap_pong_handler_t pong_handler; /** * Callback function that is used to signal events to the * application. This field is set by coap_set_event_handler(). */ coap_event_handler_t handle_event; ssize_t (*network_send)(coap_socket_t *sock, const coap_session_t *session, const uint8_t *data, size_t datalen); ssize_t (*network_read)(coap_socket_t *sock, struct coap_packet_t *packet); size_t(*get_client_psk)(const coap_session_t *session, const uint8_t *hint, size_t hint_len, uint8_t *identity, size_t *identity_len, size_t max_identity_len, uint8_t *psk, size_t max_psk_len); size_t(*get_server_psk)(const coap_session_t *session, const uint8_t *identity, size_t identity_len, uint8_t *psk, size_t max_psk_len); size_t(*get_server_hint)(const coap_session_t *session, uint8_t *hint, size_t max_hint_len); void *dtls_context; uint8_t *psk_hint; size_t psk_hint_len; uint8_t *psk_key; size_t psk_key_len; unsigned int session_timeout; /**< Number of seconds of inactivity after which an unused session will be closed. 0 means use default. */ unsigned int max_idle_sessions; /**< Maximum number of simultaneous unused sessions per endpoint. 0 means no maximum. */ unsigned int max_handshake_sessions; /**< Maximum number of simultaneous negotating sessions per endpoint. 0 means use default. */ unsigned int ping_timeout; /**< Minimum inactivity time before sending a ping message. 0 means disabled. */ unsigned int csm_timeout; /**< Timeout for waiting for a CSM from the remote side. 0 means disabled. */ void *app; /**< application-specific data */ } 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. */ COAP_STATIC_INLINE void coap_register_response_handler(coap_context_t *context, coap_response_handler_t handler) { context->response_handler = handler; } /** * Registers a new message handler that is called whenever a confirmable * message (request or response) is dropped after all retries have been * exhausted, or a rst message was received, or a network or TLS level * event was received that indicates delivering the message is not possible. * * @param context The context to register the handler for. * @param handler The nack handler to register. */ COAP_STATIC_INLINE void coap_register_nack_handler(coap_context_t *context, coap_nack_handler_t handler) { context->nack_handler = handler; } /** * Registers a new message handler that is called whenever a CoAP Ping * message is received. * * @param context The context to register the handler for. * @param handler The ping handler to register. */ COAP_STATIC_INLINE void coap_register_ping_handler(coap_context_t *context, coap_ping_handler_t handler) { context->ping_handler = handler; } /** * Registers a new message handler that is called whenever a CoAP Pong * message is received. * * @param context The context to register the handler for. * @param handler The pong handler to register. */ COAP_STATIC_INLINE void coap_register_pong_handler(coap_context_t *context, coap_pong_handler_t handler) { context->pong_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. */ COAP_STATIC_INLINE void coap_register_option(coap_context_t *ctx, uint16_t 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); /** * Set the context's default PSK hint and/or key for a server. * * @param context The current coap_context_t object. * @param hint The default PSK server hint sent to a client. If @p NULL, PSK * authentication is disabled. Empty string is a valid hint. * @param key The default PSK key. If @p NULL, PSK authentication will fail. * @param key_len The default PSK key's length. If @p 0, PSK authentication will * fail. * * @return @c 1 if successful, else @c 0. */ int coap_context_set_psk( coap_context_t *context, const char *hint, const uint8_t *key, size_t key_len ); /** * Set the context's default PKI information for a server. * * @param context The current coap_context_t object. * @param setup_data If @p NULL, PKI authentication will fail. Certificate * information required. * * @return @c 1 if successful, else @c 0. */ int coap_context_set_pki(coap_context_t *context, coap_dtls_pki_t *setup_data); /** * Set the context's default Root CA information for a client or server. * * @param context The current coap_context_t object. * @param ca_file If not @p NULL, is the full path name of a PEM encoded * file containing all the Root CAs to be used. * @param ca_dir If not @p NULL, points to a directory containing PEM * encoded files containing all the Root CAs to be used. * * @return @c 1 if successful, else @c 0. */ int coap_context_set_pki_root_cas(coap_context_t *context, const char *ca_file, const char *ca_dir); /** * Set the context keepalive timer for sessions. * A keepalive message will be sent after if a session has been inactive, * i.e. no packet sent or received, for the given number of seconds. * For reliable protocols, a PING message will be sent. If a PONG has not * been received before the next PING is due to be sent, the session will * considered as disconnected. * * @param context The coap_context_t object. * @param seconds Number of seconds for the inactivity timer, or zero * to disable CoAP-level keepalive messages. * * @return 1 if successful, else 0 */ void coap_context_set_keepalive(coap_context_t *context, unsigned int seconds); /** * Returns a new message id and updates @p session->tx_mid accordingly. The * message id is returned in network byte order to make it easier to read in * tracing tools. * * @param session The current coap_session_t object. * * @return Incremented message id in network byte order. */ COAP_STATIC_INLINE uint16_t coap_new_message_id(coap_session_t *session) { return ++session->tx_mid; } /** * CoAP stack context must be released with coap_free_context(). This function * clears all entries from the receive queue and send queue and deletes the * resources that have been registered with @p context, and frees the attached * endpoints. * * @param context The current coap_context_t object to free off. */ void coap_free_context(coap_context_t *context); /** * Stores @p data with the given CoAP context. This function * overwrites any value that has previously been stored with @p * context. * * @param context The CoAP context. * @param data The data to store with wih the context. Note that this data * must be valid during the lifetime of @p context. */ void coap_set_app_data(coap_context_t *context, void *data); /** * Returns any application-specific data that has been stored with @p * context using the function coap_set_app_data(). This function will * return @c NULL if no data has been stored. * * @param context The CoAP context. * * @return The data previously stored or @c NULL if not data stored. */ void *coap_get_app_data(const coap_context_t *context); /** * 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 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 session The CoAP session. * @param request The original request to respond to. * @param code The response 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_session_t *session, coap_pdu_t *request, 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 session The CoAP session. * @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_session_t *session, 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 session The CoAP session. * @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_session_t *session, 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 session The CoAP session. * @param request The request to be reset. * * @return The transaction id if RST was sent or @c * COAP_INVALID_TID on error. */ COAP_STATIC_INLINE coap_tid_t coap_send_rst(coap_session_t *session, coap_pdu_t *request) { return coap_send_message_type(session, request, COAP_MESSAGE_RST); } /** * Sends a CoAP message to given peer. The memory that is * allocated by pdu will be released by coap_send(). * The caller must not use the pdu after calling coap_send(). * * @param session The CoAP session. * @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_session_t *session, coap_pdu_t *pdu ); /** * Handles retransmissions of confirmable messages * * @param context The CoAP context. * @param node The node to retransmit. * * @return The message id of the sent message or @c * COAP_INVALID_TID on error. */ coap_tid_t coap_retransmit(coap_context_t *context, coap_queue_t *node); /** * For applications with their own message loop, send all pending retransmits and * return the list of sockets with events to wait for and the next timeout * The application should call coap_read, then coap_write again when any condition below is true: * - data is available on any of the sockets with the COAP_SOCKET_WANT_READ * - an incoming connection is pending in the listen queue and the COAP_SOCKET_WANT_ACCEPT flag is set * - at least some data can be written without blocking on any of the sockets with the COAP_SOCKET_WANT_WRITE flag set * - a connection event occured (success or failure) and the COAP_SOCKET_WANT_CONNECT flag is set * - the timeout has expired * Before calling coap_read or coap_write again, the application should position COAP_SOCKET_CAN_READ and COAP_SOCKET_CAN_WRITE flags as applicable. * * @param ctx The CoAP context * @param sockets array of socket descriptors, filled on output * @param max_sockets size of socket array. * @param num_sockets pointer to the number of valid entries in the socket arrays on output * @param now Current time. * * @return timeout as maxmimum number of milliseconds that the application should wait for network events or 0 if the application should wait forever. */ unsigned int coap_write(coap_context_t *ctx, coap_socket_t *sockets[], unsigned int max_sockets, unsigned int *num_sockets, coap_tick_t now ); /** * For applications with their own message loop, reads all data from the network. * * @param ctx The CoAP context * @param now Current time */ void coap_read(coap_context_t *ctx, coap_tick_t now); /** * The main message processing loop. * * @param ctx The CoAP context * @param timeout_ms Minimum number of milliseconds to wait for new messages before returning. If zero the call will block until at least one packet is sent or received. * * @return number of milliseconds spent or @c -1 if there was an error */ int coap_run_once( coap_context_t *ctx, unsigned int timeout_ms ); /** * Parses and interprets a CoAP datagram with context @p ctx. This function * returns @c 0 if the datagram was handled, or a value less than zero on * error. * * @param ctx The current CoAP context. * @param session The current CoAP session. * @param data The received packet'd data. * @param data_len The received packet'd data length. * * @return @c 0 if message was handled successfully, or less than zero on * error. */ int coap_handle_dgram(coap_context_t *ctx, coap_session_t *session, uint8_t *data, size_t data_len); /** * Invokes the event handler of @p context for the given @p event and * @p data. * * @param context The CoAP context whose event handler is to be called. * @param event The event to deliver. * @param session The session related to @p event. * @return The result from the associated event handler or 0 if none was * registered. */ int coap_handle_event(coap_context_t *context, coap_event_t event, coap_session_t *session); /** * 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 session The session to look for. * @param id The transaction 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_session_t *session, coap_tid_t id, coap_queue_t **node); coap_tid_t coap_wait_ack( coap_context_t *context, coap_session_t *session, coap_queue_t *node); /** * Retrieves transaction from the queue. * * @param queue The transaction queue to be searched. * @param session The session to find. * @param id The transaction id to find. * * @return A pointer to the transaction object or @c NULL if not found. */ coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_session_t *session, coap_tid_t id); /** * Cancels all outstanding messages for session @p session that have the specified * token. * * @param context The context in use. * @param session Session 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, coap_session_t *session, const uint8_t *token, size_t token_length); /** * Cancels all outstanding messages for session @p session. * * @param context The context in use. * @param session Session of the messages to remove. * @param reason The reasion for the session cancellation */ void coap_cancel_session_messages(coap_context_t *context, coap_session_t *session, coap_nack_reason_t reason); /** * Dispatches the PDUs from the receive queue in given context. */ void coap_dispatch(coap_context_t *context, coap_session_t *session, coap_pdu_t *pdu); /** * 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); /** * 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 either sent with coap_sent() or released by coap_delete_pdu(). * * @param context The current coap context to use. * @param session The CoAP session. * @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_session_t *session, coap_pdu_t *request); /** * Calculates the initial timeout based on the session CoAP transmission * parameters 'ack_timeout', 'ack_random_factor', and COAP_TICKS_PER_SECOND. * The calculation requires 'ack_timeout' and 'ack_random_factor' to be in * Qx.FRAC_BITS fixed point notation, whereas the passed parameter @p r * is interpreted as the fractional part of a Q0.MAX_BITS random value. * * @param session session timeout is associated with * @param r random value as fractional part of a Q0.MAX_BITS fixed point * value * @return COAP_TICKS_PER_SECOND * 'ack_timeout' * * (1 + ('ack_random_factor' - 1) * r) */ unsigned int coap_calc_timeout(coap_session_t *session, unsigned char r); #endif /* COAP_NET_H_ */