389 lines
15 KiB
C
389 lines
15 KiB
C
/*
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* pdu.h -- CoAP message structure
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*
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* Copyright (C) 2010-2014 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see README for terms
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* of use.
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*/
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/**
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* @file pdu.h
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* @brief Pre-defined constants that reflect defaults for CoAP
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*/
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#ifndef _COAP_PDU_H_
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#define _COAP_PDU_H_
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#include "uri.h"
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#ifdef WITH_LWIP
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#include <lwip/pbuf.h>
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#endif
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#define COAP_DEFAULT_PORT 5683 /* CoAP default UDP port */
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#define COAP_DEFAULT_MAX_AGE 60 /* default maximum object lifetime in seconds */
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#ifndef COAP_MAX_PDU_SIZE
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#define COAP_MAX_PDU_SIZE 1400 /* maximum size of a CoAP PDU */
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#endif /* COAP_MAX_PDU_SIZE */
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#define COAP_DEFAULT_VERSION 1 /* version of CoAP supported */
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#define COAP_DEFAULT_SCHEME "coap" /* the default scheme for CoAP URIs */
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/** well-known resources URI */
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#define COAP_DEFAULT_URI_WELLKNOWN ".well-known/core"
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#ifdef __COAP_DEFAULT_HASH
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/* pre-calculated hash key for the default well-known URI */
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#define COAP_DEFAULT_WKC_HASHKEY "\345\130\144\245"
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#endif
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/* CoAP message types */
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#define COAP_MESSAGE_CON 0 /* confirmable message (requires ACK/RST) */
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#define COAP_MESSAGE_NON 1 /* non-confirmable message (one-shot message) */
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#define COAP_MESSAGE_ACK 2 /* used to acknowledge confirmable messages */
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#define COAP_MESSAGE_RST 3 /* indicates error in received messages */
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/* CoAP request methods */
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#define COAP_REQUEST_GET 1
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#define COAP_REQUEST_POST 2
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#define COAP_REQUEST_PUT 3
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#define COAP_REQUEST_DELETE 4
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/* CoAP option types (be sure to update check_critical when adding options */
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#define COAP_OPTION_IF_MATCH 1 /* C, opaque, 0-8 B, (none) */
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#define COAP_OPTION_URI_HOST 3 /* C, String, 1-255 B, destination address */
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#define COAP_OPTION_ETAG 4 /* E, opaque, 1-8 B, (none) */
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#define COAP_OPTION_IF_NONE_MATCH 5 /* empty, 0 B, (none) */
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#define COAP_OPTION_URI_PORT 7 /* C, uint, 0-2 B, destination port */
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#define COAP_OPTION_LOCATION_PATH 8 /* E, String, 0-255 B, - */
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#define COAP_OPTION_URI_PATH 11 /* C, String, 0-255 B, (none) */
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#define COAP_OPTION_CONTENT_FORMAT 12 /* E, uint, 0-2 B, (none) */
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#define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
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#define COAP_OPTION_MAXAGE 14 /* E, uint, 0--4 B, 60 Seconds */
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#define COAP_OPTION_URI_QUERY 15 /* C, String, 1-255 B, (none) */
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#define COAP_OPTION_ACCEPT 17 /* C, uint, 0-2 B, (none) */
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#define COAP_OPTION_LOCATION_QUERY 20 /* E, String, 0-255 B, (none) */
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#define COAP_OPTION_PROXY_URI 35 /* C, String, 1-1034 B, (none) */
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#define COAP_OPTION_PROXY_SCHEME 39 /* C, String, 1-255 B, (none) */
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#define COAP_OPTION_SIZE1 60 /* E, uint, 0-4 B, (none) */
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/* option types from RFC 7641 */
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#define COAP_OPTION_OBSERVE 6 /* E, empty/uint, 0 B/0-3 B, (none) */
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#define COAP_OPTION_SUBSCRIPTION COAP_OPTION_OBSERVE
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/* selected option types from RFC 7959 */
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#define COAP_OPTION_BLOCK2 23 /* C, uint, 0--3 B, (none) */
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#define COAP_OPTION_BLOCK1 27 /* C, uint, 0--3 B, (none) */
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/* selected option types from RFC 7967 */
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#define COAP_OPTION_NORESPONSE 258 /* N, uint, 0--1 B, 0 */
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#define COAP_MAX_OPT 65535 /**< the highest option number we know */
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/* CoAP result codes (HTTP-Code / 100 * 40 + HTTP-Code % 100) */
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/* As of draft-ietf-core-coap-04, response codes are encoded to base
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* 32, i.e. the three upper bits determine the response class while
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* the remaining five fine-grained information specific to that class.
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*/
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#define COAP_RESPONSE_CODE(N) (((N)/100 << 5) | (N)%100)
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/* Determines the class of response code C */
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#define COAP_RESPONSE_CLASS(C) (((C) >> 5) & 0xFF)
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#ifndef SHORT_ERROR_RESPONSE
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/**
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* Returns a human-readable response phrase for the specified CoAP response @p
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* code. This function returns @c NULL if not found.
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*
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* @param code The response code for which the literal phrase should be
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* retrieved.
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*
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* @return A zero-terminated string describing the error, or @c NULL if not
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* found.
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*/
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char *coap_response_phrase(unsigned char code);
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#define COAP_ERROR_PHRASE_LENGTH 32 /**< maximum length of error phrase */
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#else
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#define coap_response_phrase(x) ((char *)NULL)
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#define COAP_ERROR_PHRASE_LENGTH 0 /**< maximum length of error phrase */
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#endif /* SHORT_ERROR_RESPONSE */
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/* The following definitions exist for backwards compatibility */
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#if 0 /* this does not exist any more */
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#define COAP_RESPONSE_100 40 /* 100 Continue */
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#endif
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#define COAP_RESPONSE_200 COAP_RESPONSE_CODE(200) /* 2.00 OK */
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#define COAP_RESPONSE_201 COAP_RESPONSE_CODE(201) /* 2.01 Created */
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#define COAP_RESPONSE_304 COAP_RESPONSE_CODE(203) /* 2.03 Valid */
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#define COAP_RESPONSE_400 COAP_RESPONSE_CODE(400) /* 4.00 Bad Request */
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#define COAP_RESPONSE_404 COAP_RESPONSE_CODE(404) /* 4.04 Not Found */
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#define COAP_RESPONSE_405 COAP_RESPONSE_CODE(405) /* 4.05 Method Not Allowed */
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#define COAP_RESPONSE_415 COAP_RESPONSE_CODE(415) /* 4.15 Unsupported Media Type */
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#define COAP_RESPONSE_500 COAP_RESPONSE_CODE(500) /* 5.00 Internal Server Error */
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#define COAP_RESPONSE_501 COAP_RESPONSE_CODE(501) /* 5.01 Not Implemented */
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#define COAP_RESPONSE_503 COAP_RESPONSE_CODE(503) /* 5.03 Service Unavailable */
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#define COAP_RESPONSE_504 COAP_RESPONSE_CODE(504) /* 5.04 Gateway Timeout */
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#if 0 /* these response codes do not have a valid code any more */
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# define COAP_RESPONSE_X_240 240 /* Token Option required by server */
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# define COAP_RESPONSE_X_241 241 /* Uri-Authority Option required by server */
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#endif
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#define COAP_RESPONSE_X_242 COAP_RESPONSE_CODE(402) /* Critical Option not supported */
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/* CoAP media type encoding */
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#define COAP_MEDIATYPE_TEXT_PLAIN 0 /* text/plain (UTF-8) */
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#define COAP_MEDIATYPE_APPLICATION_LINK_FORMAT 40 /* application/link-format */
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#define COAP_MEDIATYPE_APPLICATION_XML 41 /* application/xml */
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#define COAP_MEDIATYPE_APPLICATION_OCTET_STREAM 42 /* application/octet-stream */
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#define COAP_MEDIATYPE_APPLICATION_RDF_XML 43 /* application/rdf+xml */
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#define COAP_MEDIATYPE_APPLICATION_EXI 47 /* application/exi */
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#define COAP_MEDIATYPE_APPLICATION_JSON 50 /* application/json */
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#define COAP_MEDIATYPE_APPLICATION_CBOR 60 /* application/cbor */
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/* Note that identifiers for registered media types are in the range 0-65535. We
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* use an unallocated type here and hope for the best. */
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#define COAP_MEDIATYPE_ANY 0xff /* any media type */
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/**
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* coap_tid_t is used to store CoAP transaction id, i.e. a hash value
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* built from the remote transport address and the message id of a
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* CoAP PDU. Valid transaction ids are greater or equal zero.
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*/
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typedef int coap_tid_t;
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/** Indicates an invalid transaction id. */
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#define COAP_INVALID_TID -1
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/**
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* Indicates that a response is suppressed. This will occur for error
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* responses if the request was received via IP multicast.
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*/
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#define COAP_DROPPED_RESPONSE -2
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#ifdef WORDS_BIGENDIAN
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typedef struct {
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unsigned int version:2; /* protocol version */
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unsigned int type:2; /* type flag */
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unsigned int token_length:4; /* length of Token */
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unsigned int code:8; /* request method (value 1--10) or response
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code (value 40-255) */
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unsigned short id; /* message id */
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unsigned char token[]; /* the actual token, if any */
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} coap_hdr_t;
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#else
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typedef struct {
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unsigned int token_length:4; /* length of Token */
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unsigned int type:2; /* type flag */
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unsigned int version:2; /* protocol version */
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unsigned int code:8; /* request method (value 1--10) or response
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code (value 40-255) */
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unsigned short id; /* transaction id (network byte order!) */
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unsigned char token[]; /* the actual token, if any */
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} coap_hdr_t;
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#endif
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#define COAP_MESSAGE_IS_EMPTY(MSG) ((MSG)->code == 0)
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#define COAP_MESSAGE_IS_REQUEST(MSG) (!COAP_MESSAGE_IS_EMPTY(MSG) \
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&& ((MSG)->code < 32))
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#define COAP_MESSAGE_IS_RESPONSE(MSG) ((MSG)->code >= 64)
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#define COAP_OPT_LONG 0x0F /* OC == 0b1111 indicates that the option list
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* in a CoAP message is limited by 0b11110000
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* marker */
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#define COAP_OPT_END 0xF0 /* end marker */
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#define COAP_PAYLOAD_START 0xFF /* payload marker */
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/**
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* Structures for more convenient handling of options. (To be used with ordered
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* coap_list_t.) The option's data will be added to the end of the coap_option
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* structure (see macro COAP_OPTION_DATA).
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*/
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typedef struct {
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unsigned short key; /* the option key (no delta coding) */
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unsigned int length;
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} coap_option;
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#define COAP_OPTION_KEY(option) (option).key
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#define COAP_OPTION_LENGTH(option) (option).length
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#define COAP_OPTION_DATA(option) ((unsigned char *)&(option) + sizeof(coap_option))
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/**
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* Header structure for CoAP PDUs
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*/
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typedef struct {
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size_t max_size; /**< allocated storage for options and data */
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coap_hdr_t *hdr; /**< Address of the first byte of the CoAP message.
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* This may or may not equal (coap_hdr_t*)(pdu+1)
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* depending on the memory management
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* implementation. */
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unsigned short max_delta; /**< highest option number */
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unsigned short length; /**< PDU length (including header, options, data) */
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unsigned char *data; /**< payload */
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#ifdef WITH_LWIP
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struct pbuf *pbuf; /**< lwIP PBUF. The package data will always reside
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* inside the pbuf's payload, but this pointer
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* has to be kept because no exact offset can be
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* given. This field must not be accessed from
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* outside, because the pbuf's reference count
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* is checked to be 1 when the pbuf is assigned
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* to the pdu, and the pbuf stays exclusive to
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* this pdu. */
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#endif
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} coap_pdu_t;
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/**
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* Options in coap_pdu_t are accessed with the macro COAP_OPTION.
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*/
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#define COAP_OPTION(node) ((coap_option *)(node)->options)
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#ifdef WITH_LWIP
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/**
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* Creates a CoAP PDU from an lwIP @p pbuf, whose reference is passed on to this
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* function.
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*
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* The pbuf is checked for being contiguous, and for having only one reference.
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* The reference is stored in the PDU and will be freed when the PDU is freed.
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*
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* (For now, these are fatal errors; in future, a new pbuf might be allocated,
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* the data copied and the passed pbuf freed).
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*
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* This behaves like coap_pdu_init(0, 0, 0, pbuf->tot_len), and afterwards
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* copying the contents of the pbuf to the pdu.
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*
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* @return A pointer to the new PDU object or @c NULL on error.
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*/
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coap_pdu_t * coap_pdu_from_pbuf(struct pbuf *pbuf);
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#endif
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/**
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* Creates a new CoAP PDU of given @p size (must be large enough to hold the
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* basic CoAP message header (coap_hdr_t). The function returns a pointer to the
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* node coap_pdu_t object on success, or @c NULL on error. The storage allocated
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* for the result must be released with coap_delete_pdu().
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*
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* @param type The type of the PDU (one of COAP_MESSAGE_CON, COAP_MESSAGE_NON,
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* COAP_MESSAGE_ACK, COAP_MESSAGE_RST).
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* @param code The message code.
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* @param id The message id to set or COAP_INVALID_TID if unknown.
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* @param size The number of bytes to allocate for the actual message.
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*
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* @return A pointer to the new PDU object or @c NULL on error.
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*/
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coap_pdu_t *
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coap_pdu_init(unsigned char type,
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unsigned char code,
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unsigned short id,
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size_t size);
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/**
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* Clears any contents from @p pdu and resets @c version field, @c
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* length and @c data pointers. @c max_size is set to @p size, any
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* other field is set to @c 0. Note that @p pdu must be a valid
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* pointer to a coap_pdu_t object created e.g. by coap_pdu_init().
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*/
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void coap_pdu_clear(coap_pdu_t *pdu, size_t size);
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/**
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* Creates a new CoAP PDU.
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* The object is created on the heap and must be released using
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* coap_delete_pdu();
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*
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* @deprecated This function allocates the maximum storage for each
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* PDU. Use coap_pdu_init() instead.
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*/
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coap_pdu_t *coap_new_pdu(void);
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void coap_delete_pdu(coap_pdu_t *);
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/**
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* Parses @p data into the CoAP PDU structure given in @p result.
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* This function returns @c 0 on error or a number greater than zero on success.
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*
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* @param data The raw data to parse as CoAP PDU.
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* @param length The actual size of @p data.
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* @param result The PDU structure to fill. Note that the structure must
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* provide space for at least @p length bytes to hold the
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* entire CoAP PDU.
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*
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* @return A value greater than zero on success or @c 0 on error.
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*/
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int coap_pdu_parse(unsigned char *data,
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size_t length,
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coap_pdu_t *result);
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/**
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* Adds token of length @p len to @p pdu.
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* Adding the token destroys any following contents of the pdu. Hence options
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* and data must be added after coap_add_token() has been called. In @p pdu,
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* length is set to @p len + @c 4, and max_delta is set to @c 0. This funtion
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* returns @c 0 on error or a value greater than zero on success.
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*
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* @param pdu The PDU where the token is to be added.
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* @param len The length of the new token.
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* @param data The token to add.
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*
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* @return A value greater than zero on success, or @c 0 on error.
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*/
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int coap_add_token(coap_pdu_t *pdu,
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size_t len,
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const unsigned char *data);
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/**
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* Adds option of given type to pdu that is passed as first
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* parameter.
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* coap_add_option() destroys the PDU's data, so coap_add_data() must be called
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* after all options have been added. As coap_add_token() destroys the options
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* following the token, the token must be added before coap_add_option() is
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* called. This function returns the number of bytes written or @c 0 on error.
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*/
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size_t coap_add_option(coap_pdu_t *pdu,
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unsigned short type,
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unsigned int len,
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const unsigned char *data);
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/**
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* Adds option of given type to pdu that is passed as first parameter, but does
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* not write a value. It works like coap_add_option with respect to calling
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* sequence (i.e. after token and before data). This function returns a memory
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* address to which the option data has to be written before the PDU can be
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* sent, or @c NULL on error.
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*/
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unsigned char *coap_add_option_later(coap_pdu_t *pdu,
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unsigned short type,
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unsigned int len);
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/**
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* Adds given data to the pdu that is passed as first parameter. Note that the
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* PDU's data is destroyed by coap_add_option(). coap_add_data() must be called
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* only once per PDU, otherwise the result is undefined.
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*/
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int coap_add_data(coap_pdu_t *pdu,
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unsigned int len,
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const unsigned char *data);
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/**
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* Retrieves the length and data pointer of specified PDU. Returns 0 on error or
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* 1 if *len and *data have correct values. Note that these values are destroyed
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* with the pdu.
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*/
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int coap_get_data(coap_pdu_t *pdu,
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size_t *len,
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unsigned char **data);
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#endif /* _COAP_PDU_H_ */
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