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.
22 #warning "assertions are disabled"
29 #ifdef HAVE_NETINET_IN_H
30 #include <netinet/in.h>
35 #ifdef HAVE_SYS_TIME_H
40 #include <lwip/ip_addr.h>
47 #include "coap_time.h"
51 typedef struct coap_queue_t {
52 struct coap_queue_t *next;
54 coap_tick_t t; /**< when to send PDU for the next time */
55 unsigned char retransmit_cnt; /**< retransmission counter, will be removed when zero */
56 unsigned int timeout; /**< the randomized timeout value */
58 coap_address_t local; /**< local address */
59 coap_address_t remote; /**< remote address */
60 coap_tid_t id; /**< unique transaction id */
62 coap_pdu_t *pdu; /**< the CoAP PDU to send */
65 /** Adds node to given queue, ordered by node->t. */
66 int coap_insert_node(coap_queue_t **queue, coap_queue_t *node);
68 /** Destroys specified node. */
69 int coap_delete_node(coap_queue_t *node);
71 /** Removes all items from given queue and frees the allocated storage. */
72 void coap_delete_all(coap_queue_t *queue);
74 /** Creates a new node suitable for adding to the CoAP sendqueue. */
75 coap_queue_t *coap_new_node();
77 struct coap_resource_t;
78 struct coap_context_t;
80 struct coap_async_state_t;
83 /** Message handler that is used as call-back in coap_context_t */
84 typedef void (*coap_request_handler_t)(struct coap_context_t *,
85 const coap_queue_t * rcvd);
87 /** Message handler that is used as call-back in coap_context_t */
88 typedef void (*coap_response_handler_t)(struct coap_context_t *,
89 const coap_queue_t * rcvd);
91 #define COAP_MID_CACHE_SIZE 3
93 unsigned char flags[COAP_MID_CACHE_SIZE];
94 coap_key_t item[COAP_MID_CACHE_SIZE];
97 /** The CoAP stack's global state is stored in a coap_context_t object */
98 typedef struct coap_context_t {
99 coap_opt_filter_t known_options;
101 struct coap_resource_t *resources; /**< hash table or list of known resources */
102 #endif /* WITH_CONTIKI */
103 #ifndef WITHOUT_ASYNC
104 /** list of asynchronous transactions */
105 struct coap_async_state_t *async_state;
106 #endif /* WITHOUT_ASYNC */
108 * The time stamp in the first element of the sendqeue is relative
109 * to sendqueue_basetime. */
110 coap_tick_t sendqueue_basetime;
111 coap_queue_t *sendqueue, *recvqueue;
113 int sockfd; /**< send/receive socket */
114 int sockfd_wellknown; /**< well-known discovery socket */
115 #endif /* WITH_POSIX */
117 struct uip_udp_conn *conn; /**< uIP connection object */
119 struct etimer retransmit_timer; /**< fires when the next packet must be sent */
120 struct etimer notify_timer; /**< used to check resources periodically */
121 #endif /* WITH_CONTIKI */
123 struct udp_pcb *pcb; /**< the underlying lwIP UDP PCB */
124 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. */
125 ip_addr_t pending_address; /**< the address associated with pending_package */
126 u16_t pending_port; /**< the port associated with pending_package */
128 uint8_t timer_configured; /**< Set to 1 when a retransmission is scheduled using lwIP timers for this context, otherwise 0. */
129 #endif /* WITH_LWIP */
132 * The last message id that was used is stored in this field. The
133 * initial value is set by coap_new_context() and is usually a
134 * random value. A new message id can be created with
135 * coap_new_message_id().
137 unsigned short message_id;
140 * The next value to be used for Observe. This field is global for
141 * all resources and will be updated when notifications are created.
143 unsigned int observe;
145 coap_request_handler_t request_handler;
146 coap_response_handler_t response_handler;
150 * Registers a new message handler that is called whenever a request
151 * was received that matches an ongoing transaction.
153 * @param context The context to register the handler for.
154 * @param handler The response handler to register.
157 coap_register_request_handler(coap_context_t *context,
158 coap_request_handler_t handler) {
159 context->request_handler = handler;
163 * Registers a new message handler that is called whenever a response
164 * was received that matches an ongoing transaction.
166 * @param context The context to register the handler for.
167 * @param handler The response handler to register.
170 coap_register_response_handler(coap_context_t *context,
171 coap_response_handler_t handler) {
172 context->response_handler = handler;
176 * Registers the option type @p type with the given context object @p
179 * @param ctx The context to use.
180 * @param type The option type to register.
183 coap_register_option(coap_context_t *ctx, unsigned char type) {
184 coap_option_setb(ctx->known_options, type);
189 * Set sendqueue_basetime in the given context object @p ctx to @p
190 * now. This function returns the number of elements in the queue
191 * head that have timed out.
193 unsigned int coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now);
195 /** Returns the next pdu to send without removing from sendqeue. */
196 coap_queue_t *coap_peek_next( coap_context_t *context );
198 /** Returns the next pdu to send and removes it from the sendqeue. */
199 coap_queue_t *coap_pop_next( coap_context_t *context );
201 /** Creates a new coap_context_t object that will hold the CoAP stack status. */
202 coap_context_t *coap_new_context(const coap_address_t *listen_addr);
204 /** Joins the CoAP stack to well-known multicast address. */
205 int coap_join_wellknown_group(coap_context_t *context,
206 const coap_address_t *multicast_addr);
209 * Returns a new message id and updates @p context->message_id
210 * accordingly. The message id is returned in network byte order
211 * to make it easier to read in tracing tools.
213 * @param context the current coap_context_t object
214 * @return incremented message id in network byte order
216 static inline unsigned short
217 coap_new_message_id(coap_context_t *context) {
219 return htons(++(context->message_id));
220 #else /* WITH_CONTIKI */
221 return uip_htons(++context->message_id);
225 /* CoAP stack context must be released with coap_free_context() */
226 void coap_free_context( coap_context_t *context );
230 * Sends a confirmed CoAP message to given destination. The memory
231 * that is allocated by pdu will not be released by
232 * coap_send_confirmed(). The caller must release the memory.
234 * @param context The CoAP context to use.
235 * @param dst The address to send to.
236 * @param pdu The CoAP PDU to send.
237 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
239 coap_tid_t coap_send_confirmed(coap_context_t *context,
240 const coap_address_t *dst,
244 * Creates a new ACK PDU with specified error @p code. The options
245 * specified by the filter expression @p opts will be copied from the
246 * original request contained in @p request. Unless @c
247 * SHORT_ERROR_RESPONSE was defined at build time, the textual reason
248 * phrase for @p code will be added as payload, with Content-Type @c
249 * 0. This function returns a pointer to the new response message, or
250 * @c NULL on error. The storage allocated for the new message must be
251 * relased with coap_free().
253 * @param request Specification of the received (confirmable) request.
254 * @param code The error code to set.
255 * @param opts An option filter that specifies which options to copy
256 * from the original request in @p node.
258 * @return A pointer to the new message or @c NULL on error.
260 coap_pdu_t *coap_new_error_response(coap_pdu_t *request,
262 coap_opt_filter_t opts);
264 * Sends a non-confirmed CoAP message to given destination. The memory
265 * that is allocated by pdu will not be released by coap_send().
266 * The caller must release the memory.
268 * @param context The CoAP context to use.
269 * @param dst The address to send to.
270 * @param pdu The CoAP PDU to send.
271 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
273 coap_tid_t coap_send(coap_context_t *context,
274 const coap_address_t *dst,
278 * Sends an error response with code @p code for request @p request to
279 * @p dst. @p opts will be passed to coap_new_error_response() to
280 * copy marked options from the request. This function returns the
281 * transaction id if the message was sent, or @c COAP_INVALID_TID
284 * @param context The context to use.
285 * @param request The original request to respond to.
286 * @param dst The remote peer that sent the request.
287 * @param code The reponse code.
288 * @param opts A filter that specifies the options to copy from the
291 * @return The transaction id if the message was sent, or @c
292 * COAP_INVALID_TID otherwise.
294 coap_tid_t coap_send_error(coap_context_t *context,
296 const coap_address_t *dst,
298 coap_opt_filter_t opts);
301 * Helper funktion to create and send a message with @p type (usually
302 * ACK or RST). This function returns @c COAP_INVALID_TID when the
303 * message was not sent, a valid transaction id otherwise.
305 * @param context The CoAP context.
306 * @param dst Where to send the context.
307 * @param request The request that should be responded to.
308 * @param type Which type to set
309 * @return transaction id on success or @c COAP_INVALID_TID otherwise.
312 coap_send_message_type(coap_context_t *context,
313 const coap_address_t *dst,
317 * Sends an ACK message with code @c 0 for the specified @p request to
318 * @p dst. This function returns the corresponding transaction id if
319 * the message was sent or @c COAP_INVALID_TID on error.
321 * @param context The context to use.
322 * @param dst The destination address.
323 * @param request The request to be acknowledged.
325 * @return The transaction id if ACK was sent or @c COAP_INVALID_TID
328 coap_tid_t coap_send_ack(coap_context_t *context,
329 const coap_address_t *dst,
330 coap_pdu_t *request);
333 * Sends an RST message with code @c 0 for the specified @p request to
334 * @p dst. This function returns the corresponding transaction id if
335 * the message was sent or @c COAP_INVALID_TID on error.
337 * @param context The context to use.
338 * @param dst The destination address.
339 * @param request The request to be reset.
341 * @return The transaction id if RST was sent or @c COAP_INVALID_TID
344 static inline coap_tid_t
345 coap_send_rst(coap_context_t *context,
346 const coap_address_t *dst,
347 coap_pdu_t *request) {
348 return coap_send_message_type(context, dst, request, COAP_MESSAGE_RST);
351 /** Handles retransmissions of confirmable messages */
352 coap_tid_t coap_retransmit( coap_context_t *context, coap_queue_t *node );
355 * Reads data from the network and tries to parse as CoAP PDU. On success, 0 is returned
356 * and a new node with the parsed PDU is added to the receive queue in the specified context
359 int coap_read( coap_context_t *context, int sockfd );
362 * Calculates a unique transaction id from given arguments @p peer and
363 * @p pdu. The id is returned in @p id.
365 * @param peer The remote party who sent @p pdu.
366 * @param pdu The message that initiated the transaction.
367 * @param id Set to the new id.
369 void coap_transaction_id(const coap_address_t *peer, const coap_pdu_t *pdu,
373 * This function removes the element with given @p id from the list
374 * given list. If @p id was found, @p node is updated to point to the
375 * removed element. Note that the storage allocated by @p node is
376 * @b not released. The caller must do this manually using
377 * coap_delete_node(). This function returns @c 1 if the element with
378 * id @p id was found, @c 0 otherwise. For a return value of @c 0,
379 * the contents of @p node is undefined.
381 * @param queue The queue to search for @p id.
382 * @param id The node id to look for.
383 * @param node If found, @p node is updated to point to the
384 * removed node. You must release the storage pointed to by
387 * @return @c 1 if @p id was found, @c 0 otherwise.
389 int coap_remove_from_queue(coap_queue_t **queue,
391 coap_queue_t **node);
394 * Removes the transaction identified by @p id from given @p queue.
395 * This is a convenience function for coap_remove_from_queue() with
396 * automatic deletion of the removed node.
398 * @param queue The queue to search for @p id.
399 * @param id The transaction id.
401 * @return @c 1 if node was found, removed and destroyed, @c 0 otherwise.
404 coap_remove_transaction(coap_queue_t **queue, coap_tid_t id) {
406 if (!coap_remove_from_queue(queue, id, &node))
409 coap_delete_node(node);
414 * Retrieves transaction from queue.
415 * @queue The transaction queue to be searched
416 * @id Unique key of the transaction to find.
417 * @return A pointer to the transaction object or NULL if not found
419 coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_tid_t id);
422 * Cancels all outstanding messages for peer @p dst that have the
425 * @param context The context in use
426 * @param dst Destination address of the messages to remove.
427 * @param token Message token
428 * @param token_length Actual length of @p token
430 void coap_cancel_all_messages(coap_context_t *context,
431 const coap_address_t *dst,
432 const unsigned char *token,
433 size_t token_length);
435 /** Dispatches the PDUs from the receive queue in given context. */
436 void coap_dispatch( coap_context_t *context );
438 /** Returns 1 if there are no messages to send or to dispatch in the context's queues. */
439 int coap_can_exit( coap_context_t *context );
442 * Returns the current value of an internal tick counter. The counter
443 * counts \c COAP_TICKS_PER_SECOND ticks every second.
445 void coap_ticks(coap_tick_t *);
448 * Verifies that @p pdu contains no unknown critical options. Options
449 * must be registered at @p ctx, using the function
450 * coap_register_option(). A basic set of options is registered
451 * automatically by coap_new_context(). This function returns @c 1 if
452 * @p pdu is ok, @c 0 otherwise. The given filter object @p unknown
453 * will be updated with the unknown options. As only @c COAP_MAX_OPT
454 * options can be signalled this way, remaining options must be
458 coap_opt_filter_t f = COAP_OPT_NONE;
459 coap_opt_iterator_t opt_iter;
461 if (coap_option_check_critical(ctx, pdu, f) == 0) {
462 coap_option_iterator_init(pdu, &opt_iter, f);
464 while (coap_option_next(&opt_iter)) {
465 if (opt_iter.type & 0x01) {
466 ... handle unknown critical option in opt_iter ...
472 * @param ctx The context where all known options are registered.
473 * @param pdu The PDU to check.
474 * @param unknown The output filter that will be updated to indicate the
475 * unknown critical options found in @p pdu.
477 * @return @c 1 if everything was ok, @c 0 otherwise.
479 int coap_option_check_critical(coap_context_t *ctx,
481 coap_opt_filter_t unknown);
487 #endif /* _COAP_NET_H_ */