/*
* pdu.h -- CoAP message structure
*
* Copyright (C) 2010-2014 Olaf Bergmann <bergmann@tzi.org>
*
* This file is part of the CoAP library libcoap. Please see README for terms
* of use.
*/
/**
* @file pdu.h
* @brief Pre-defined constants that reflect defaults for CoAP
*/
#ifndef _COAP_PDU_H_
#define _COAP_PDU_H_
#include "uri.h"
#ifdef WITH_LWIP
#include <lwip/pbuf.h>
#endif
#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 */
/** well-known resources URI */
#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 RFC 7641 */
#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 RFC 7959 */
#define COAP_OPTION_BLOCK2 23 /* C, uint, 0--3 B, (none) */
#define COAP_OPTION_BLOCK1 27 /* C, uint, 0--3 B, (none) */
/* selected option types from RFC 7967 */
#define COAP_OPTION_NORESPONSE 258 /* N, uint, 0--1 B, 0 */
#define COAP_MAX_OPT 65535 /**< the highest option number we know */
/* 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
/**
* Returns a human-readable response phrase for the specified CoAP response @p
* code. This function returns @c NULL if not found.
*
* @param code The response code for which the literal phrase should be
* retrieved.
*
* @return A zero-terminated string describing the error, or @c NULL if not
* found.
*/
char *coap_response_phrase(unsigned char code);
#define COAP_ERROR_PHRASE_LENGTH 32 /**< maximum length of error phrase */
#else
#define coap_response_phrase(x) ((char *)NULL)
#define COAP_ERROR_PHRASE_LENGTH 0 /**< maximum length of error phrase */
#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 */
#define COAP_MEDIATYPE_APPLICATION_CBOR 60 /* application/cbor */
/* 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_tid_t is used to store CoAP transaction id, i.e. a hash value
* built from the remote transport address and the message id of a
* CoAP PDU. Valid transaction ids are greater or equal zero.
*/
typedef int coap_tid_t;
/** Indicates an invalid transaction id. */
#define COAP_INVALID_TID -1
/**
* Indicates that a response is suppressed. This will occur for error
* responses if the request was received via IP multicast.
*/
#define COAP_DROPPED_RESPONSE -2
#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)
#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 */
/**
* Structures for more convenient handling of options. (To be used with ordered
* coap_list_t.) The option's data will be added to the end of the coap_option
* structure (see macro COAP_OPTION_DATA).
*/
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))
/**
* Header structure for CoAP PDUs
*/
typedef struct {
size_t max_size; /**< allocated storage for options and data */
coap_hdr_t *hdr; /**< Address of the first byte of the CoAP message.
* This may or may not equal (coap_hdr_t*)(pdu+1)
* depending on the memory management
* implementation. */
unsigned short max_delta; /**< highest option number */
unsigned short length; /**< PDU length (including header, options, data) */
unsigned char *data; /**< payload */
#ifdef WITH_LWIP
struct pbuf *pbuf; /**< lwIP PBUF. The package data will always reside
* inside the pbuf's payload, but this pointer
* has to be kept because no exact offset can be
* given. This field must not be accessed from
* outside, because the pbuf's reference count
* is checked to be 1 when the pbuf is assigned
* to the pdu, and the pbuf stays exclusive to
* this pdu. */
#endif
} coap_pdu_t;
/**
* Options in coap_pdu_t are accessed with the macro COAP_OPTION.
*/
#define COAP_OPTION(node) ((coap_option *)(node)->options)
#ifdef WITH_LWIP
/**
* Creates a CoAP PDU from an lwIP @p pbuf, whose reference is passed on to this
* function.
*
* The pbuf is checked for being contiguous, and for having only one reference.
* The reference is stored in the PDU and will be freed when the PDU is freed.
*
* (For now, these are fatal errors; in future, a new pbuf might be allocated,
* the data copied and the passed pbuf freed).
*
* This behaves like coap_pdu_init(0, 0, 0, pbuf->tot_len), and afterwards
* copying the contents of the pbuf to the pdu.
*
* @return A pointer to the new PDU object or @c NULL on error.
*/
coap_pdu_t * coap_pdu_from_pbuf(struct pbuf *pbuf);
#endif
/**
* Creates a new CoAP PDU of given @p size (must be large enough to hold the
* basic CoAP message header (coap_hdr_t). The function returns a pointer to the
* node coap_pdu_t object on success, or @c NULL on error. The storage allocated
* for the result must be released with coap_delete_pdu().
*
* @param type The type of the PDU (one of COAP_MESSAGE_CON, COAP_MESSAGE_NON,
* COAP_MESSAGE_ACK, COAP_MESSAGE_RST).
* @param code The message code.
* @param id The message id to set or COAP_INVALID_TID if unknown.
* @param size The number of bytes to allocate for the actual message.
*
* @return A pointer to the new PDU object or @c NULL on error.
*/
coap_pdu_t *
coap_pdu_init(unsigned char type,
unsigned char code,
unsigned short id,
size_t size);
/**
* Clears any contents from @p pdu and resets @c version field, @c
* length and @c data pointers. @c max_size is set to @p size, any
* other field is set to @c 0. Note that @p pdu must be a valid
* pointer to a coap_pdu_t object created e.g. by coap_pdu_init().
*/
void coap_pdu_clear(coap_pdu_t *pdu, size_t size);
/**
* Creates a new CoAP PDU.
* The object is created on the heap and must be released using
* coap_delete_pdu();
*
* @deprecated This function allocates the maximum storage for each
* PDU. Use coap_pdu_init() instead.
*/
coap_pdu_t *coap_new_pdu(void);
void coap_delete_pdu(coap_pdu_t *);
/**
* Parses @p data into the CoAP PDU structure given in @p result.
* This function returns @c 0 on error or a number greater than zero on success.
*
* @param data The raw data to parse as CoAP PDU.
* @param length The actual size of @p data.
* @param result The PDU structure to fill. Note that the structure must
* provide space for at least @p length bytes to hold the
* entire CoAP PDU.
*
* @return A value greater than zero on success or @c 0 on error.
*/
int coap_pdu_parse(unsigned char *data,
size_t length,
coap_pdu_t *result);
/**
* Adds token of length @p len to @p pdu.
* Adding the token destroys any following contents of the pdu. Hence options
* and data must be added after coap_add_token() has been called. In @p pdu,
* length is set to @p len + @c 4, and max_delta is set to @c 0. This funtion
* returns @c 0 on error or a value greater than zero on success.
*
* @param pdu The PDU where the token is to be added.
* @param len The length of the new token.
* @param data The token to add.
*
* @return A value greater than zero on success, or @c 0 on error.
*/
int coap_add_token(coap_pdu_t *pdu,
size_t len,
const unsigned char *data);
/**
* Adds option of given type to pdu that is passed as first
* parameter.
* coap_add_option() destroys the PDU's data, so coap_add_data() must be called
* after all options have been added. As coap_add_token() destroys the options
* following the token, the token must be added before coap_add_option() is
* called. This function returns the number of bytes written or @c 0 on error.
*/
size_t coap_add_option(coap_pdu_t *pdu,
unsigned short type,
unsigned int len,
const unsigned char *data);
/**
* Adds option of given type to pdu that is passed as first parameter, but does
* not write a value. It works like coap_add_option with respect to calling
* sequence (i.e. after token and before data). This function returns a memory
* address to which the option data has to be written before the PDU can be
* sent, or @c NULL on error.
*/
unsigned char *coap_add_option_later(coap_pdu_t *pdu,
unsigned short type,
unsigned int len);
/**
* Adds given data to the pdu that is passed as first parameter. Note that the
* PDU's data is destroyed by coap_add_option(). coap_add_data() must be called
* only once per PDU, otherwise the result is undefined.
*/
int coap_add_data(coap_pdu_t *pdu,
unsigned int len,
const unsigned char *data);
/**
* Retrieves the length and data pointer of specified PDU. Returns 0 on error or
* 1 if *len and *data have correct values. Note that these values are destroyed
* with the pdu.
*/
int coap_get_data(coap_pdu_t *pdu,
size_t *len,
unsigned char **data);
#endif /* _COAP_PDU_H_ */