pdu.h

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/* pdu.h -- CoAP message structure
 *
 * Copyright (C) 2010--2012 Olaf Bergmann <bergmann@tzi.org>
 *
 * This file is part of the CoAP library libcoap. Please see
 * README for terms of use. 
 */

#ifndef _PDU_H_
#define _PDU_H_

#include "config.h"
#include "coap_list.h"
#include "uri.h"

/* pre-defined constants that reflect defaults for CoAP */

#define COAP_DEFAULT_RESPONSE_TIMEOUT  2 /* response timeout in seconds */
#define COAP_DEFAULT_MAX_RETRANSMIT    4 /* max number of retransmissions */
#define COAP_DEFAULT_PORT           5683 /* CoAP default UDP port */
#define COAP_DEFAULT_MAX_AGE          60 /* default maximum object lifetime in seconds */
#ifndef COAP_MAX_PDU_SIZE
#define COAP_MAX_PDU_SIZE           1400 /* maximum size of a CoAP PDU */
#endif /* COAP_MAX_PDU_SIZE */

#define COAP_DEFAULT_VERSION           1 /* version of CoAP supported */
#define COAP_DEFAULT_SCHEME        "coap" /* the default scheme for CoAP URIs */

#define COAP_DEFAULT_URI_WELLKNOWN ".well-known/core"

#ifdef __COAP_DEFAULT_HASH
/* pre-calculated hash key for the default well-known URI */
#define COAP_DEFAULT_WKC_HASHKEY   "\345\130\144\245"
#endif

/* CoAP message types */

#define COAP_MESSAGE_CON               0 /* confirmable message (requires ACK/RST) */
#define COAP_MESSAGE_NON               1 /* non-confirmable message (one-shot message) */
#define COAP_MESSAGE_ACK               2 /* used to acknowledge confirmable messages */
#define COAP_MESSAGE_RST               3 /* indicates error in received messages */

/* CoAP request methods */

#define COAP_REQUEST_GET       1
#define COAP_REQUEST_POST      2
#define COAP_REQUEST_PUT       3
#define COAP_REQUEST_DELETE    4

/* CoAP option types (be sure to update check_critical when adding options */

#define COAP_OPTION_IF_MATCH      1 /* C, opaque, 0-8 B, (none) */
#define COAP_OPTION_URI_HOST      3 /* C, String, 1-255 B, destination address */
#define COAP_OPTION_ETAG          4 /* E, opaque, 1-8 B, (none) */
#define COAP_OPTION_IF_NONE_MATCH 5 /* empty, 0 B, (none) */
#define COAP_OPTION_URI_PORT      7 /* C, uint, 0-2 B, destination port */
#define COAP_OPTION_LOCATION_PATH 8 /* E, String, 0-255 B, - */
#define COAP_OPTION_URI_PATH     11 /* C, String, 0-255 B, (none) */
#define COAP_OPTION_CONTENT_FORMAT 12 /* E, uint, 0-2 B, (none) */
#define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
#define COAP_OPTION_MAXAGE       14 /* E, uint, 0--4 B, 60 Seconds */
#define COAP_OPTION_URI_QUERY    15 /* C, String, 1-255 B, (none) */
#define COAP_OPTION_ACCEPT       17 /* C, uint,   0-2 B, (none) */
#define COAP_OPTION_LOCATION_QUERY 20 /* E, String,   0-255 B, (none) */
#define COAP_OPTION_PROXY_URI    35 /* C, String, 1-1034 B, (none) */
#define COAP_OPTION_PROXY_SCHEME 39 /* C, String, 1-255 B, (none) */
#define COAP_OPTION_SIZE1        60 /* E, uint, 0-4 B, (none) */

/* option types from draft-ietf-coap-observe-09 */

#define COAP_OPTION_OBSERVE       6 /* E, empty/uint, 0 B/0-3 B, (none) */
#define COAP_OPTION_SUBSCRIPTION  COAP_OPTION_OBSERVE

/* selected option types from draft-core-block-04 */

#define COAP_OPTION_BLOCK2       23 /* C, uint, 0--3 B, (none) */
#define COAP_OPTION_BLOCK1       27 /* C, uint, 0--3 B, (none) */

#define COAP_MAX_OPT             63 
/* CoAP result codes (HTTP-Code / 100 * 40 + HTTP-Code % 100) */

/* As of draft-ietf-core-coap-04, response codes are encoded to base
 * 32, i.e.  the three upper bits determine the response class while
 * the remaining five fine-grained information specific to that class.
 */
#define COAP_RESPONSE_CODE(N) (((N)/100 << 5) | (N)%100)

/* Determines the class of response code C */
#define COAP_RESPONSE_CLASS(C) (((C) >> 5) & 0xFF)

#ifndef SHORT_ERROR_RESPONSE

char *coap_response_phrase(unsigned char code);

#define COAP_ERROR_PHRASE_LENGTH 32 
#else
#define coap_response_phrase(x) ((char *)NULL)

#define COAP_ERROR_PHRASE_LENGTH 0 
#endif /* SHORT_ERROR_RESPONSE */

/* The following definitions exist for backwards compatibility */
#if 0 /* this does not exist any more */
#define COAP_RESPONSE_100      40 /* 100 Continue */
#endif
#define COAP_RESPONSE_200      COAP_RESPONSE_CODE(200)  /* 2.00 OK */
#define COAP_RESPONSE_201      COAP_RESPONSE_CODE(201)  /* 2.01 Created */
#define COAP_RESPONSE_304      COAP_RESPONSE_CODE(203)  /* 2.03 Valid */
#define COAP_RESPONSE_400      COAP_RESPONSE_CODE(400)  /* 4.00 Bad Request */
#define COAP_RESPONSE_404      COAP_RESPONSE_CODE(404)  /* 4.04 Not Found */
#define COAP_RESPONSE_405      COAP_RESPONSE_CODE(405)  /* 4.05 Method Not Allowed */
#define COAP_RESPONSE_415      COAP_RESPONSE_CODE(415)  /* 4.15 Unsupported Media Type */
#define COAP_RESPONSE_500      COAP_RESPONSE_CODE(500)  /* 5.00 Internal Server Error */
#define COAP_RESPONSE_501      COAP_RESPONSE_CODE(501)  /* 5.01 Not Implemented */
#define COAP_RESPONSE_503      COAP_RESPONSE_CODE(503)  /* 5.03 Service Unavailable */
#define COAP_RESPONSE_504      COAP_RESPONSE_CODE(504)  /* 5.04 Gateway Timeout */
#if 0  /* these response codes do not have a valid code any more */
#  define COAP_RESPONSE_X_240    240   /* Token Option required by server */
#  define COAP_RESPONSE_X_241    241   /* Uri-Authority Option required by server */
#endif
#define COAP_RESPONSE_X_242    COAP_RESPONSE_CODE(402)  /* Critical Option not supported */

/* CoAP media type encoding */

#define COAP_MEDIATYPE_TEXT_PLAIN                     0 /* text/plain (UTF-8) */
#define COAP_MEDIATYPE_APPLICATION_LINK_FORMAT       40 /* application/link-format */
#define COAP_MEDIATYPE_APPLICATION_XML               41 /* application/xml */
#define COAP_MEDIATYPE_APPLICATION_OCTET_STREAM      42 /* application/octet-stream */
#define COAP_MEDIATYPE_APPLICATION_RDF_XML           43 /* application/rdf+xml */
#define COAP_MEDIATYPE_APPLICATION_EXI               47 /* application/exi  */
#define COAP_MEDIATYPE_APPLICATION_JSON              50 /* application/json  */

/* Note that identifiers for registered media types are in the range 0-65535. We
 * use an unallocated type here and hope for the best. */
#define COAP_MEDIATYPE_ANY                         0xff /* any media type */

/* CoAP transaction id */
/*typedef unsigned short coap_tid_t; */
typedef int coap_tid_t;
#define COAP_INVALID_TID -1

#ifdef WORDS_BIGENDIAN
typedef struct {
  unsigned int version:2;   /* protocol version */
  unsigned int type:2;      /* type flag */
  unsigned int token_length:4;  /* length of Token */
  unsigned int code:8;          /* request method (value 1--10) or response code (value 40-255) */
  unsigned short id;        /* message id */
  unsigned char token[];    /* the actual token, if any */
} coap_hdr_t;
#else
typedef struct {
  unsigned int token_length:4;  /* length of Token */
  unsigned int type:2;      /* type flag */
  unsigned int version:2;   /* protocol version */
  unsigned int code:8;          /* request method (value 1--10) or response code (value 40-255) */
  unsigned short id;        /* transaction id (network byte order!) */
  unsigned char token[];    /* the actual token, if any */
} coap_hdr_t;
#endif

#define COAP_MESSAGE_IS_EMPTY(MSG)    ((MSG)->code == 0)
#define COAP_MESSAGE_IS_REQUEST(MSG)  (!COAP_MESSAGE_IS_EMPTY(MSG)  \
                       && ((MSG)->code < 32))
#define COAP_MESSAGE_IS_RESPONSE(MSG) ((MSG)->code >= 64 && (MSG)->code <= 191)

#define COAP_OPT_LONG 0x0F  /* OC == 0b1111 indicates that the option list in a
                 * CoAP message is limited by 0b11110000 marker */

#define COAP_OPT_END 0xF0   /* end marker */

#define COAP_PAYLOAD_START 0xFF /* payload marker */

typedef struct {
  unsigned short key;       /* the option key (no delta coding) */
  unsigned int length;
} coap_option;

#define COAP_OPTION_KEY(option) (option).key
#define COAP_OPTION_LENGTH(option) (option).length
#define COAP_OPTION_DATA(option) ((unsigned char *)&(option) + sizeof(coap_option))

typedef struct {
  size_t max_size;  
  coap_hdr_t *hdr;
  unsigned short max_delta; 
  unsigned short length;    
  unsigned char *data;      
} coap_pdu_t;

#define COAP_OPTION(node) ((coap_option *)(node)->options)

coap_pdu_t *
coap_pdu_init(unsigned char type, unsigned char code, 
          unsigned short id, size_t size);

void coap_pdu_clear(coap_pdu_t *pdu, size_t size);

coap_pdu_t *coap_new_pdu();

void coap_delete_pdu(coap_pdu_t *);

int coap_pdu_parse(unsigned char *data, size_t length, coap_pdu_t *result);

int coap_add_token(coap_pdu_t *pdu, size_t len, const unsigned char *data);

size_t coap_add_option(coap_pdu_t *pdu, unsigned short type, 
               unsigned int len, const unsigned char *data);

int coap_add_data(coap_pdu_t *pdu, unsigned int len, const unsigned char *data);

int coap_get_data(coap_pdu_t *pdu, size_t *len, unsigned char **data);

#endif /* _PDU_H_ */