[contrib/iotivity.git] / resource / csdk / libcoap-4.1.1 / net.h

/* net.h -- CoAP network interface
 *
 * Copyright (C) 2010--2013 Olaf Bergmann <bergmann@tzi.org>
 *
 * 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 WITH_ARDUINO
#include "Time.h"
#endif /* WITH_ARDUINO */

#ifdef __cplusplus
extern "C" {
#endif

#include "config.h"

#ifdef HAVE_ASSERT_H
#include <assert.h>
#else
#ifndef assert
#warning "assertions are disabled"
#  define assert(x)
#endif
#endif

#include <stdlib.h>
#include <string.h>
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_TIME_H
#include <time.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

#ifdef WITH_LWIP
#include <lwip/ip_addr.h>
#endif

#include "option.h"
#include "address.h"
#include "prng.h"
#include "pdu.h"
#include "coap_time.h"

typedef enum {
    SEND_NOW            = (1 << 0), /*Flag used when sending non-confirmable, ACK and RESET coap pdus*/
    SEND_NOW_CON        = (1 << 1), /*Flag used when sending confirmable coap pdu*/
    SEND_DELAYED        = (1 << 2), /*Flag used to delay the transmission of coap pdu*/
    SEND_RETX           = (1 << 3), /*Flag used to retransmit a confirmable pdu*/
    SEND_SECURE_PORT    = (1 << 4) /*Flag used to indicate that PDU needs to be transmitted on secure port */
} coap_send_flags_t;

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 */

  unsigned char delayedResponse;  /**< delayed response flag */
  unsigned char secure;      /**< rx/tx will use secure channel (DTLS) */
} 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 for requests that is used as call-back in coap_context_t */
typedef void (*coap_request_handler_t)(struct coap_context_t  *,
        const coap_queue_t * rcvd);

/** Message handler for responses that is used as call-back in coap_context_t */
typedef void (*coap_response_handler_t)(struct coap_context_t  *,
        const coap_queue_t * rcvd);

/** Message handler for ack and rst that is used as call-back in coap_context_t */
typedef void (*coap_ack_rst_handler_t)(struct coap_context_t  *, uint8_t msgType,
        const coap_queue_t * sent);

#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;
#ifndef WITH_CONTIKI
  struct coap_resource_t *resources; /**< hash table or list of known resources */
#endif /* WITH_CONTIKI */
#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;
#if defined(WITH_POSIX) || defined(WITH_ARDUINO)
  int sockfd;           /**< send/receive socket */
  int sockfd_wellknown; /**< well-known discovery socket */
#endif /* WITH_POSIX || WITH_ARDUINO */
#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
  struct udp_pcb *pcb; /**< the underlying lwIP UDP PCB */
  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. */
  ip_addr_t pending_address; /**< the address associated with pending_package */
  u16_t pending_port; /**< the port associated with pending_package */

  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().
   */
  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_request_handler_t request_handler;
  coap_response_handler_t response_handler;
  coap_ack_rst_handler_t ack_rst_handler;
} coap_context_t;

/**
 * Registers a new message handler that is called whenever a request
 * 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_request_handler(coap_context_t *context,
                   coap_request_handler_t handler) {
  context->request_handler = handler;
}

/**
 * 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 a new message handler that is called whenever ack or rst
 * was received that matches an ongoing transaction.
 *
 * @param context The context to register the handler for.
 * @param handler The handler to register.
 */
static inline void
coap_register_ack_rst_handler(coap_context_t *context,
                   coap_ack_rst_handler_t handler) {
  context->ack_rst_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);

/** Joins the CoAP stack to well-known multicast address.  */
int coap_join_wellknown_group(coap_context_t *context,
                const coap_address_t *multicast_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) {
    ++(context->message_id);
#ifdef WITH_ARDUINO
  return ((context->message_id << 8) | ((context->message_id >> 8) & (0xFF)));
#elif WITH_CONTIKI
  return uip_htons(context->message_id);
#else
  return htons(context->message_id);
#endif
}

/* 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 CoAP message to given destination. The memory
 * that is allocated by pdu will be released by coap_send().
 *
 * @param context The CoAP context to use.
 * @param dst     The address to send to.
 * @param pdu     The CoAP PDU to send.
 * @param flag    The flag indicating how the message will be 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,
                 coap_send_flags_t flag);

/**
 * 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,
               coap_send_flags_t flag);

/**
 * 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
 * @param flag options for sending the message
 * @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,
               coap_send_flags_t flag,
               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.
 * @param flag    Options for sending the acknowledgement.
 *
 * @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,
             coap_send_flags_t flag);

/**
 * 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.
 * @param flag    Options for sending the reset message.
 *
 * @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,
          coap_send_flags_t flag) {
  return coap_send_message_type(context, dst, request, flag, 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, int sockfd );

/**
 * 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);

#ifdef __cplusplus
}
#endif

#endif /* _COAP_NET_H_ */