1 /* net.h -- CoAP network interface
3 * Copyright (C) 2010--2013 Olaf Bergmann <bergmann@tzi.org>
5 * This file is part of the CoAP library libcoap. Please see
6 * README for terms of use.
14 #endif /* WITH_ARDUINO */
26 #warning "assertions are disabled"
33 #ifdef HAVE_NETINET_IN_H
34 #include <netinet/in.h>
39 #ifdef HAVE_SYS_TIME_H
44 #include <lwip/ip_addr.h>
51 #include "coap_time.h"
54 SEND_NOW = (1 << 0), /*Flag used when sending non-confirmable, ACK and RESET coap pdus*/
55 SEND_NOW_CON = (1 << 1), /*Flag used when sending confirmable coap pdu*/
56 SEND_DELAYED = (1 << 2), /*Flag used to delay the transmission of coap pdu*/
57 SEND_RETX = (1 << 3), /*Flag used to retransmit a confirmable pdu*/
58 SEND_SECURE_PORT = (1 << 4) /*Flag used to indicate that PDU needs to
59 be transmitted on secure port */
64 typedef struct coap_queue_t {
65 struct coap_queue_t *next;
67 coap_tick_t t; /**< when to send PDU for the next time */
68 unsigned char retransmit_cnt; /**< retransmission counter, will be removed when zero */
69 unsigned int timeout; /**< the randomized timeout value */
71 coap_address_t local; /**< local address */
72 coap_address_t remote; /**< remote address */
73 coap_tid_t id; /**< unique transaction id */
75 coap_pdu_t *pdu; /**< the CoAP PDU to send */
77 unsigned char delayedResponse; /**< delayed response flag */
78 unsigned char secure; /**< rx/tx will use secure channel (DTLS) */
81 /** Adds node to given queue, ordered by node->t. */
82 int coap_insert_node(coap_queue_t **queue, coap_queue_t *node);
84 /** Destroys specified node. */
85 int coap_delete_node(coap_queue_t *node);
87 /** Removes all items from given queue and frees the allocated storage. */
88 void coap_delete_all(coap_queue_t *queue);
90 /** Creates a new node suitable for adding to the CoAP sendqueue. */
91 coap_queue_t *coap_new_node();
93 struct coap_resource_t;
94 struct coap_context_t;
96 struct coap_async_state_t;
99 struct coap_dtls_context_t;
101 /** Message handler for requests that is used as call-back in coap_context_t */
102 typedef void (*coap_request_handler_t)(struct coap_context_t *,
103 const coap_queue_t * rcvd);
105 /** Message handler for responses that is used as call-back in coap_context_t */
106 typedef void (*coap_response_handler_t)(struct coap_context_t *,
107 const coap_queue_t * rcvd);
109 /** Message handler for ack and rst that is used as call-back in coap_context_t */
110 typedef void (*coap_ack_rst_handler_t)(struct coap_context_t *, uint8_t msgType,
111 const coap_queue_t * sent);
113 #define COAP_MID_CACHE_SIZE 3
115 unsigned char flags[COAP_MID_CACHE_SIZE];
116 coap_key_t item[COAP_MID_CACHE_SIZE];
119 /** The CoAP stack's global state is stored in a coap_context_t object */
120 typedef struct coap_context_t {
121 coap_opt_filter_t known_options;
123 struct coap_resource_t *resources; /**< hash table or list of known resources */
124 #endif /* WITH_CONTIKI */
125 #ifndef WITHOUT_ASYNC
126 /** list of asynchronous transactions */
127 struct coap_async_state_t *async_state;
128 #endif /* WITHOUT_ASYNC */
130 * The time stamp in the first element of the sendqeue is relative
131 * to sendqueue_basetime. */
132 coap_tick_t sendqueue_basetime;
133 coap_queue_t *sendqueue, *recvqueue;
134 #if defined(WITH_POSIX) || defined(WITH_ARDUINO)
135 int sockfd; /**< send/receive socket */
136 int sockfd_wellknown; /**< well-known discovery socket */
137 int sockfd_dtls; /**< secure communication happens on this socket */
138 /** dtls interface */
139 struct coap_dtls_context_t *coap_dtls_ctx;
140 #endif /* WITH_POSIX || WITH_ARDUINO */
142 struct uip_udp_conn *conn; /**< uIP connection object */
144 struct etimer retransmit_timer; /**< fires when the next packet must be sent */
145 struct etimer notify_timer; /**< used to check resources periodically */
146 #endif /* WITH_CONTIKI */
148 struct udp_pcb *pcb; /**< the underlying lwIP UDP PCB */
149 struct pbuf *pending_package; /**< pbuf containing the last received package if not handled yet. This is only used to pass the package from the udp_recv callback into the coap_read function, which frees the pbuf and clears this field. */
150 ip_addr_t pending_address; /**< the address associated with pending_package */
151 u16_t pending_port; /**< the port associated with pending_package */
153 uint8_t timer_configured; /**< Set to 1 when a retransmission is scheduled using lwIP timers for this context, otherwise 0. */
154 #endif /* WITH_LWIP */
157 * The last message id that was used is stored in this field. The
158 * initial value is set by coap_new_context() and is usually a
159 * random value. A new message id can be created with
160 * coap_new_message_id().
162 unsigned short message_id;
165 * The next value to be used for Observe. This field is global for
166 * all resources and will be updated when notifications are created.
168 unsigned int observe;
170 coap_request_handler_t request_handler;
171 coap_response_handler_t response_handler;
172 coap_ack_rst_handler_t ack_rst_handler;
176 * Registers a new message handler that is called whenever a request
177 * was received that matches an ongoing transaction.
179 * @param context The context to register the handler for.
180 * @param handler The response handler to register.
183 coap_register_request_handler(coap_context_t *context,
184 coap_request_handler_t handler) {
185 context->request_handler = handler;
189 * Registers a new message handler that is called whenever a response
190 * was received that matches an ongoing transaction.
192 * @param context The context to register the handler for.
193 * @param handler The response handler to register.
196 coap_register_response_handler(coap_context_t *context,
197 coap_response_handler_t handler) {
198 context->response_handler = handler;
202 * Registers a new message handler that is called whenever ack or rst
203 * was received that matches an ongoing transaction.
205 * @param context The context to register the handler for.
206 * @param handler The handler to register.
209 coap_register_ack_rst_handler(coap_context_t *context,
210 coap_ack_rst_handler_t handler) {
211 context->ack_rst_handler = handler;
215 * Registers the option type @p type with the given context object @p
218 * @param ctx The context to use.
219 * @param type The option type to register.
222 coap_register_option(coap_context_t *ctx, unsigned char type) {
223 coap_option_setb(ctx->known_options, type);
228 * Set sendqueue_basetime in the given context object @p ctx to @p
229 * now. This function returns the number of elements in the queue
230 * head that have timed out.
232 unsigned int coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now);
234 /** Returns the next pdu to send without removing from sendqeue. */
235 coap_queue_t *coap_peek_next( coap_context_t *context );
237 /** Returns the next pdu to send and removes it from the sendqeue. */
238 coap_queue_t *coap_pop_next( coap_context_t *context );
240 /** Creates a new coap_context_t object that will hold the CoAP stack status. */
241 coap_context_t *coap_new_context(const coap_address_t *listen_addr);
243 /** Joins the CoAP stack to well-known multicast address. */
244 int coap_join_wellknown_group(coap_context_t *context,
245 const coap_address_t *multicast_addr);
248 * Returns a new message id and updates @p context->message_id
249 * accordingly. The message id is returned in network byte order
250 * to make it easier to read in tracing tools.
252 * @param context the current coap_context_t object
253 * @return incremented message id in network byte order
255 static inline unsigned short
256 coap_new_message_id(coap_context_t *context) {
257 ++(context->message_id);
259 return ((context->message_id << 8) | ((context->message_id >> 8) & (0xFF)));
261 return uip_htons(context->message_id);
263 return htons(context->message_id);
267 /* CoAP stack context must be released with coap_free_context() */
268 void coap_free_context( coap_context_t *context );
271 * Sends a confirmed CoAP message to given destination. The memory
272 * that is allocated by pdu will not be released by
273 * coap_send_confirmed(). The caller must release the memory.
275 * @param context The CoAP context to use.
276 * @param dst The address to send to.
277 * @param pdu The CoAP PDU to send.
278 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
280 coap_tid_t coap_send_confirmed(coap_context_t *context,
281 const coap_address_t *dst,
285 * Creates a new ACK PDU with specified error @p code. The options
286 * specified by the filter expression @p opts will be copied from the
287 * original request contained in @p request. Unless @c
288 * SHORT_ERROR_RESPONSE was defined at build time, the textual reason
289 * phrase for @p code will be added as payload, with Content-Type @c
290 * 0. This function returns a pointer to the new response message, or
291 * @c NULL on error. The storage allocated for the new message must be
292 * relased with coap_free().
294 * @param request Specification of the received (confirmable) request.
295 * @param code The error code to set.
296 * @param opts An option filter that specifies which options to copy
297 * from the original request in @p node.
299 * @return A pointer to the new message or @c NULL on error.
301 coap_pdu_t *coap_new_error_response(coap_pdu_t *request,
303 coap_opt_filter_t opts);
305 * Sends a CoAP message to given destination. The memory
306 * that is allocated by pdu will be released by coap_send().
308 * @param context The CoAP context to use.
309 * @param dst The address to send to.
310 * @param pdu The CoAP PDU to send.
311 * @param flag The flag indicating how the message will be send
312 * @param cache_flag When DTLS library determines that a secure session does
313 * not exist with the peer yet, it caches the 'pdu pointer'
314 * so that it can be sent later and 'coap_send' sets this
315 * variable to TRUE to instruct the caller of this method
316 * to not delete the 'pdu'.
317 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
319 coap_tid_t coap_send(coap_context_t *context, const coap_address_t *dst,
321 coap_send_flags_t flags,
322 uint8_t *cache_flag);
325 * Sends an error response with code @p code for request @p request to
326 * @p dst. @p opts will be passed to coap_new_error_response() to
327 * copy marked options from the request. This function returns the
328 * transaction id if the message was sent, or @c COAP_INVALID_TID
331 * @param context The context to use.
332 * @param request The original request to respond to.
333 * @param dst The remote peer that sent the request.
334 * @param code The reponse code.
335 * @param opts A filter that specifies the options to copy from the
338 * @return The transaction id if the message was sent, or @c
339 * COAP_INVALID_TID otherwise.
341 coap_tid_t coap_send_error(coap_context_t *context,
343 const coap_address_t *dst,
345 coap_opt_filter_t opts,
346 coap_send_flags_t flag);
349 * Helper funktion to create and send a message with @p type (usually
350 * ACK or RST). This function returns @c COAP_INVALID_TID when the
351 * message was not sent, a valid transaction id otherwise.
353 * @param context The CoAP context.
354 * @param dst Where to send the context.
355 * @param request The request that should be responded to.
356 * @param type Which type to set
357 * @param flag options for sending the message
358 * @return transaction id on success or @c COAP_INVALID_TID otherwise.
361 coap_send_message_type(coap_context_t *context,
362 const coap_address_t *dst,
364 coap_send_flags_t flag,
367 * Sends an ACK message with code @c 0 for the specified @p request to
368 * @p dst. This function returns the corresponding transaction id if
369 * the message was sent or @c COAP_INVALID_TID on error.
371 * @param context The context to use.
372 * @param dst The destination address.
373 * @param request The request to be acknowledged.
374 * @param flag Options for sending the acknowledgement.
376 * @return The transaction id if ACK was sent or @c COAP_INVALID_TID
379 coap_tid_t coap_send_ack(coap_context_t *context,
380 const coap_address_t *dst,
382 coap_send_flags_t flag);
385 * Sends an RST message with code @c 0 for the specified @p request to
386 * @p dst. This function returns the corresponding transaction id if
387 * the message was sent or @c COAP_INVALID_TID on error.
389 * @param context The context to use.
390 * @param dst The destination address.
391 * @param request The request to be reset.
392 * @param flag Options for sending the reset message.
394 * @return The transaction id if RST was sent or @c COAP_INVALID_TID
397 static inline coap_tid_t
398 coap_send_rst(coap_context_t *context,
399 const coap_address_t *dst,
401 coap_send_flags_t flag) {
402 return coap_send_message_type(context, dst, request, flag, COAP_MESSAGE_RST);
405 /** Handles retransmissions of confirmable messages */
406 coap_tid_t coap_retransmit( coap_context_t *context, coap_queue_t *node);
409 * Reads data from the network and tries to parse as CoAP PDU. On success, 0 is returned
410 * and a new node with the parsed PDU is added to the receive queue in the specified context
413 int coap_read( coap_context_t *context, int sockfd );
416 * Calculates a unique transaction id from given arguments @p peer and
417 * @p pdu. The id is returned in @p id.
419 * @param peer The remote party who sent @p pdu.
420 * @param pdu The message that initiated the transaction.
421 * @param id Set to the new id.
423 void coap_transaction_id(const coap_address_t *peer, const coap_pdu_t *pdu,
427 * This function removes the element with given @p id from the list
428 * given list. If @p id was found, @p node is updated to point to the
429 * removed element. Note that the storage allocated by @p node is
430 * @b not released. The caller must do this manually using
431 * coap_delete_node(). This function returns @c 1 if the element with
432 * id @p id was found, @c 0 otherwise. For a return value of @c 0,
433 * the contents of @p node is undefined.
435 * @param queue The queue to search for @p id.
436 * @param id The node id to look for.
437 * @param node If found, @p node is updated to point to the
438 * removed node. You must release the storage pointed to by
441 * @return @c 1 if @p id was found, @c 0 otherwise.
443 int coap_remove_from_queue(coap_queue_t **queue,
445 coap_queue_t **node);
448 * Removes the transaction identified by @p id from given @p queue.
449 * This is a convenience function for coap_remove_from_queue() with
450 * automatic deletion of the removed node.
452 * @param queue The queue to search for @p id.
453 * @param id The transaction id.
455 * @return @c 1 if node was found, removed and destroyed, @c 0 otherwise.
458 coap_remove_transaction(coap_queue_t **queue, coap_tid_t id) {
460 if (!coap_remove_from_queue(queue, id, &node))
463 coap_delete_node(node);
468 * Retrieves transaction from queue.
469 * @queue The transaction queue to be searched
470 * @id Unique key of the transaction to find.
471 * @return A pointer to the transaction object or NULL if not found
473 coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_tid_t id);
476 * Cancels all outstanding messages for peer @p dst that have the
479 * @param context The context in use
480 * @param dst Destination address of the messages to remove.
481 * @param token Message token
482 * @param token_length Actual length of @p token
484 void coap_cancel_all_messages(coap_context_t *context,
485 const coap_address_t *dst,
486 const unsigned char *token,
487 size_t token_length);
489 /** Dispatches the PDUs from the receive queue in given context. */
490 void coap_dispatch( coap_context_t *context );
492 /** Returns 1 if there are no messages to send or to dispatch in the context's queues. */
493 int coap_can_exit( coap_context_t *context );
496 * Returns the current value of an internal tick counter. The counter
497 * counts \c COAP_TICKS_PER_SECOND ticks every second.
499 void coap_ticks(coap_tick_t *);
502 * Verifies that @p pdu contains no unknown critical options. Options
503 * must be registered at @p ctx, using the function
504 * coap_register_option(). A basic set of options is registered
505 * automatically by coap_new_context(). This function returns @c 1 if
506 * @p pdu is ok, @c 0 otherwise. The given filter object @p unknown
507 * will be updated with the unknown options. As only @c COAP_MAX_OPT
508 * options can be signalled this way, remaining options must be
512 coap_opt_filter_t f = COAP_OPT_NONE;
513 coap_opt_iterator_t opt_iter;
515 if (coap_option_check_critical(ctx, pdu, f) == 0) {
516 coap_option_iterator_init(pdu, &opt_iter, f);
518 while (coap_option_next(&opt_iter)) {
519 if (opt_iter.type & 0x01) {
520 ... handle unknown critical option in opt_iter ...
526 * @param ctx The context where all known options are registered.
527 * @param pdu The PDU to check.
528 * @param unknown The output filter that will be updated to indicate the
529 * unknown critical options found in @p pdu.
531 * @return @c 1 if everything was ok, @c 0 otherwise.
533 int coap_option_check_critical(coap_context_t *ctx,
535 coap_opt_filter_t unknown);
541 #endif /* _COAP_NET_H_ */