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,
55 // ACK and RESET coap pdus, Automatically set in SendCoAPPdu
56 // Do not use in upper stack APIs
57 SEND_NOW_CON = (1 << 1), // Flag used when sending confirmable coap pdu,
58 // Automatically set in SendCoAPPdu,
59 // Do not use in upper stack APIs
60 SEND_DELAYED = (1 << 2), // Flag used to delay the transmission of coap pdu
61 SEND_RETX = (1 << 3), // Flag used to retransmit a confirmable pdu
62 SEND_SECURE_PORT = (1 << 4) // Flag used to indicate that PDU needs to
63 // be transmitted on secure port
68 typedef struct coap_queue_t {
69 struct coap_queue_t *next;
71 coap_tick_t t; /**< when to send PDU for the next time */
72 unsigned char retransmit_cnt; /**< retransmission counter, will be removed when zero */
73 unsigned int timeout; /**< the randomized timeout value */
75 coap_address_t local; /**< local address */
76 coap_address_t remote; /**< remote address */
77 coap_tid_t id; /**< unique transaction id */
79 coap_pdu_t *pdu; /**< the CoAP PDU to send */
81 unsigned char delayedResNeeded; /**< delayed response flag */
82 unsigned char secure; /**< rx/tx will use secure channel (DTLS) */
85 /** Adds node to given queue, ordered by node->t. */
86 int coap_insert_node(coap_queue_t **queue, coap_queue_t *node);
88 /** Destroys specified node. */
89 int coap_delete_node(coap_queue_t *node);
91 /** Removes all items from given queue and frees the allocated storage. */
92 void coap_delete_all(coap_queue_t *queue);
94 /** Creates a new node suitable for adding to the CoAP sendqueue. */
95 coap_queue_t *coap_new_node();
97 struct coap_resource_t;
98 struct coap_context_t;
100 struct coap_async_state_t;
103 struct coap_dtls_context_t;
105 /** Message handler for requests that is used as call-back in coap_context_t */
106 typedef void (*coap_request_handler_t)(struct coap_context_t *,
107 const coap_queue_t * rcvd);
109 /** Message handler for responses that is used as call-back in coap_context_t */
110 typedef void (*coap_response_handler_t)(struct coap_context_t *,
111 const coap_queue_t * rcvd);
113 /** Message handler for ack and rst that is used as call-back in coap_context_t */
114 typedef void (*coap_ack_rst_handler_t)(struct coap_context_t *, uint8_t msgType,
115 const coap_queue_t * sent);
117 #define COAP_MID_CACHE_SIZE 3
119 unsigned char flags[COAP_MID_CACHE_SIZE];
120 coap_key_t item[COAP_MID_CACHE_SIZE];
123 /** The CoAP stack's global state is stored in a coap_context_t object */
124 typedef struct coap_context_t {
125 coap_opt_filter_t known_options;
127 struct coap_resource_t *resources; /**< hash table or list of known resources */
128 #endif /* WITH_CONTIKI */
129 #ifndef WITHOUT_ASYNC
130 /** list of asynchronous transactions */
131 struct coap_async_state_t *async_state;
132 #endif /* WITHOUT_ASYNC */
134 * The time stamp in the first element of the sendqeue is relative
135 * to sendqueue_basetime. */
136 coap_tick_t sendqueue_basetime;
137 coap_queue_t *sendqueue, *recvqueue;
138 #if defined(WITH_POSIX) || defined(WITH_ARDUINO)
139 int sockfd; /**< send/receive socket */
140 int sockfd_wellknown; /**< well-known discovery socket */
141 int sockfd_dtls; /**< secure communication happens on this socket */
142 /** dtls interface */
143 struct coap_dtls_context_t *coap_dtls_ctx;
144 #endif /* WITH_POSIX || WITH_ARDUINO */
146 struct uip_udp_conn *conn; /**< uIP connection object */
148 struct etimer retransmit_timer; /**< fires when the next packet must be sent */
149 struct etimer notify_timer; /**< used to check resources periodically */
150 #endif /* WITH_CONTIKI */
152 struct udp_pcb *pcb; /**< the underlying lwIP UDP PCB */
153 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. */
154 ip_addr_t pending_address; /**< the address associated with pending_package */
155 u16_t pending_port; /**< the port associated with pending_package */
157 uint8_t timer_configured; /**< Set to 1 when a retransmission is scheduled using lwIP timers for this context, otherwise 0. */
158 #endif /* WITH_LWIP */
161 * The last message id that was used is stored in this field. The
162 * initial value is set by coap_new_context() and is usually a
163 * random value. A new message id can be created with
164 * coap_new_message_id().
166 unsigned short message_id;
169 * The next value to be used for Observe. This field is global for
170 * all resources and will be updated when notifications are created.
172 unsigned int observe;
174 coap_request_handler_t request_handler;
175 coap_response_handler_t response_handler;
176 coap_ack_rst_handler_t ack_rst_handler;
180 * Registers a new message handler that is called whenever a request
181 * was received that matches an ongoing transaction.
183 * @param context The context to register the handler for.
184 * @param handler The response handler to register.
187 coap_register_request_handler(coap_context_t *context,
188 coap_request_handler_t handler) {
189 context->request_handler = handler;
193 * Registers a new message handler that is called whenever a response
194 * was received that matches an ongoing transaction.
196 * @param context The context to register the handler for.
197 * @param handler The response handler to register.
200 coap_register_response_handler(coap_context_t *context,
201 coap_response_handler_t handler) {
202 context->response_handler = handler;
206 * Registers a new message handler that is called whenever ack or rst
207 * was received that matches an ongoing transaction.
209 * @param context The context to register the handler for.
210 * @param handler The handler to register.
213 coap_register_ack_rst_handler(coap_context_t *context,
214 coap_ack_rst_handler_t handler) {
215 context->ack_rst_handler = handler;
219 * Registers the option type @p type with the given context object @p
222 * @param ctx The context to use.
223 * @param type The option type to register.
226 coap_register_option(coap_context_t *ctx, unsigned char type) {
227 coap_option_setb(ctx->known_options, type);
232 * Set sendqueue_basetime in the given context object @p ctx to @p
233 * now. This function returns the number of elements in the queue
234 * head that have timed out.
236 unsigned int coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now);
238 /** Returns the next pdu to send without removing from sendqeue. */
239 coap_queue_t *coap_peek_next( coap_context_t *context );
241 /** Returns the next pdu to send and removes it from the sendqeue. */
242 coap_queue_t *coap_pop_next( coap_context_t *context );
244 /** Creates a new coap_context_t object that will hold the CoAP stack status. */
245 coap_context_t *coap_new_context(uint8_t ipAddr[], uint16_t port);
247 /** Joins the CoAP stack to well-known multicast address. */
248 int coap_join_wellknown_group(coap_context_t *context,
249 const coap_address_t *multicast_addr);
252 * Returns a new message id and updates @p context->message_id
253 * accordingly. The message id is returned in network byte order
254 * to make it easier to read in tracing tools.
256 * @param context the current coap_context_t object
257 * @return incremented message id in network byte order
259 static inline unsigned short
260 coap_new_message_id(coap_context_t *context) {
261 ++(context->message_id);
263 return ((context->message_id << 8) | ((context->message_id >> 8) & (0xFF)));
265 return uip_htons(context->message_id);
267 return htons(context->message_id);
271 /* CoAP stack context must be released with coap_free_context() */
272 void coap_free_context( coap_context_t *context );
275 * Sends a confirmed CoAP message to given destination. The memory
276 * that is allocated by pdu will not be released by
277 * coap_send_confirmed(). The caller must release the memory.
279 * @param context The CoAP context to use.
280 * @param dst The address to send to.
281 * @param pdu The CoAP PDU to send.
282 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
284 coap_tid_t coap_send_confirmed(coap_context_t *context,
285 const coap_address_t *dst,
289 * Creates a new ACK PDU with specified error @p code. The options
290 * specified by the filter expression @p opts will be copied from the
291 * original request contained in @p request. Unless @c
292 * SHORT_ERROR_RESPONSE was defined at build time, the textual reason
293 * phrase for @p code will be added as payload, with Content-Type @c
294 * 0. This function returns a pointer to the new response message, or
295 * @c NULL on error. The storage allocated for the new message must be
296 * relased with coap_free().
298 * @param request Specification of the received (confirmable) request.
299 * @param code The error code to set.
300 * @param opts An option filter that specifies which options to copy
301 * from the original request in @p node.
303 * @return A pointer to the new message or @c NULL on error.
305 coap_pdu_t *coap_new_error_response(coap_pdu_t *request,
307 coap_opt_filter_t opts);
309 * Sends a CoAP message to given destination. The memory
310 * that is allocated by pdu will be released by coap_send().
312 * @param context The CoAP context to use.
313 * @param dst The address to send to.
314 * @param pdu The CoAP PDU to send.
315 * @param flag The flag indicating how the message will be send
316 * @param cache_flag When DTLS library determines that a secure session does
317 * not exist with the peer yet, it caches the 'pdu pointer'
318 * so that it can be sent later and 'coap_send' sets this
319 * variable to TRUE to instruct the caller of this method
320 * to not delete the 'pdu'.
321 * @return The message id of the sent message or @c COAP_INVALID_TID on error.
323 coap_tid_t coap_send(coap_context_t *context, const coap_address_t *dst,
325 coap_send_flags_t flags,
326 uint8_t *cache_flag);
329 * Sends an error response with code @p code for request @p request to
330 * @p dst. @p opts will be passed to coap_new_error_response() to
331 * copy marked options from the request. This function returns the
332 * transaction id if the message was sent, or @c COAP_INVALID_TID
335 * @param context The context to use.
336 * @param request The original request to respond to.
337 * @param dst The remote peer that sent the request.
338 * @param code The reponse code.
339 * @param opts A filter that specifies the options to copy from the
342 * @return The transaction id if the message was sent, or @c
343 * COAP_INVALID_TID otherwise.
345 coap_tid_t coap_send_error(coap_context_t *context,
347 const coap_address_t *dst,
349 coap_opt_filter_t opts,
350 coap_send_flags_t flag);
353 * Helper funktion to create and send a message with @p type (usually
354 * ACK or RST). This function returns @c COAP_INVALID_TID when the
355 * message was not sent, a valid transaction id otherwise.
357 * @param context The CoAP context.
358 * @param dst Where to send the context.
359 * @param request The request that should be responded to.
360 * @param type Which type to set
361 * @param flag options for sending the message
362 * @return transaction id on success or @c COAP_INVALID_TID otherwise.
365 coap_send_message_type(coap_context_t *context,
366 const coap_address_t *dst,
368 coap_send_flags_t flag,
371 * Sends an ACK message with code @c 0 for the specified @p request to
372 * @p dst. This function returns the corresponding transaction id if
373 * the message was sent or @c COAP_INVALID_TID on error.
375 * @param context The context to use.
376 * @param dst The destination address.
377 * @param request The request to be acknowledged.
378 * @param flag Options for sending the acknowledgement.
380 * @return The transaction id if ACK was sent or @c COAP_INVALID_TID
383 coap_tid_t coap_send_ack(coap_context_t *context,
384 const coap_address_t *dst,
386 coap_send_flags_t flag);
389 * Sends an RST message with code @c 0 for the specified @p request to
390 * @p dst. This function returns the corresponding transaction id if
391 * the message was sent or @c COAP_INVALID_TID on error.
393 * @param context The context to use.
394 * @param dst The destination address.
395 * @param request The request to be reset.
396 * @param flag Options for sending the reset message.
398 * @return The transaction id if RST was sent or @c COAP_INVALID_TID
401 static inline coap_tid_t
402 coap_send_rst(coap_context_t *context,
403 const coap_address_t *dst,
405 coap_send_flags_t flag) {
406 return coap_send_message_type(context, dst, request, flag, COAP_MESSAGE_RST);
409 /** Handles retransmissions of confirmable messages */
410 coap_tid_t coap_retransmit( coap_context_t *context, coap_queue_t *node);
413 * Reads data from the network and tries to parse as CoAP PDU. On success, 0 is returned
414 * and a new node with the parsed PDU is added to the receive queue in the specified context
417 int coap_read( coap_context_t *context, int sockfd );
420 * Calculates a unique transaction id from given arguments @p peer and
421 * @p pdu. The id is returned in @p id.
423 * @param peer The remote party who sent @p pdu.
424 * @param pdu The message that initiated the transaction.
425 * @param id Set to the new id.
427 void coap_transaction_id(const coap_address_t *peer, const coap_pdu_t *pdu,
431 * This function removes the element with given @p id from the list
432 * given list. If @p id was found, @p node is updated to point to the
433 * removed element. Note that the storage allocated by @p node is
434 * @b not released. The caller must do this manually using
435 * coap_delete_node(). This function returns @c 1 if the element with
436 * id @p id was found, @c 0 otherwise. For a return value of @c 0,
437 * the contents of @p node is undefined.
439 * @param queue The queue to search for @p id.
440 * @param id The node id to look for.
441 * @param node If found, @p node is updated to point to the
442 * removed node. You must release the storage pointed to by
445 * @return @c 1 if @p id was found, @c 0 otherwise.
447 int coap_remove_from_queue(coap_queue_t **queue,
449 coap_queue_t **node);
452 * Removes the transaction identified by @p id from given @p queue.
453 * This is a convenience function for coap_remove_from_queue() with
454 * automatic deletion of the removed node.
456 * @param queue The queue to search for @p id.
457 * @param id The transaction id.
459 * @return @c 1 if node was found, removed and destroyed, @c 0 otherwise.
462 coap_remove_transaction(coap_queue_t **queue, coap_tid_t id) {
464 if (!coap_remove_from_queue(queue, id, &node))
467 coap_delete_node(node);
472 * Retrieves transaction from queue.
473 * @queue The transaction queue to be searched
474 * @id Unique key of the transaction to find.
475 * @return A pointer to the transaction object or NULL if not found
477 coap_queue_t *coap_find_transaction(coap_queue_t *queue, coap_tid_t id);
480 * Cancels all outstanding messages for peer @p dst that have the
483 * @param context The context in use
484 * @param dst Destination address of the messages to remove.
485 * @param token Message token
486 * @param token_length Actual length of @p token
488 void coap_cancel_all_messages(coap_context_t *context,
489 const coap_address_t *dst,
490 const unsigned char *token,
491 size_t token_length);
493 /** Dispatches the PDUs from the receive queue in given context. */
494 void coap_dispatch( coap_context_t *context );
496 /** Returns 1 if there are no messages to send or to dispatch in the context's queues. */
497 int coap_can_exit( coap_context_t *context );
500 * Returns the current value of an internal tick counter. The counter
501 * counts \c COAP_TICKS_PER_SECOND ticks every second.
503 void coap_ticks(coap_tick_t *);
506 * Verifies that @p pdu contains no unknown critical options. Options
507 * must be registered at @p ctx, using the function
508 * coap_register_option(). A basic set of options is registered
509 * automatically by coap_new_context(). This function returns @c 1 if
510 * @p pdu is ok, @c 0 otherwise. The given filter object @p unknown
511 * will be updated with the unknown options. As only @c COAP_MAX_OPT
512 * options can be signalled this way, remaining options must be
516 coap_opt_filter_t f = COAP_OPT_NONE;
517 coap_opt_iterator_t opt_iter;
519 if (coap_option_check_critical(ctx, pdu, f) == 0) {
520 coap_option_iterator_init(pdu, &opt_iter, f);
522 while (coap_option_next(&opt_iter)) {
523 if (opt_iter.type & 0x01) {
524 ... handle unknown critical option in opt_iter ...
530 * @param ctx The context where all known options are registered.
531 * @param pdu The PDU to check.
532 * @param unknown The output filter that will be updated to indicate the
533 * unknown critical options found in @p pdu.
535 * @return @c 1 if everything was ok, @c 0 otherwise.
537 int coap_option_check_critical(coap_context_t *ctx,
539 coap_opt_filter_t unknown);
545 #endif /* _COAP_NET_H_ */