1 /* pdu.h -- CoAP message structure
3 * Copyright (C) 2010--2012 Olaf Bergmann <bergmann@tzi.org>
5 * This file is part of the CoAP library libcoap. Please see
6 * README for terms of use.
13 #include "coap_list.h"
17 #include <lwip/pbuf.h>
20 /* pre-defined constants that reflect defaults for CoAP */
22 #define COAP_DEFAULT_RESPONSE_TIMEOUT 2 /* response timeout in seconds */
23 #define COAP_DEFAULT_MAX_RETRANSMIT 4 /* max number of retransmissions */
24 #define COAP_DEFAULT_PORT 5683 /* CoAP default UDP port */
25 #define COAP_DEFAULT_MAX_AGE 60 /* default maximum object lifetime in seconds */
26 #ifndef COAP_MAX_PDU_SIZE
27 #define COAP_MAX_PDU_SIZE 1400 /* maximum size of a CoAP PDU */
28 #endif /* COAP_MAX_PDU_SIZE */
30 #define COAP_DEFAULT_VERSION 1 /* version of CoAP supported */
31 #define COAP_DEFAULT_SCHEME "coap" /* the default scheme for CoAP URIs */
33 /** well-known resources URI */
34 #define COAP_DEFAULT_URI_WELLKNOWN ".well-known/core"
36 #ifdef __COAP_DEFAULT_HASH
37 /* pre-calculated hash key for the default well-known URI */
38 #define COAP_DEFAULT_WKC_HASHKEY "\345\130\144\245"
41 /* CoAP message types */
43 #define COAP_MESSAGE_CON 0 /* confirmable message (requires ACK/RST) */
44 #define COAP_MESSAGE_NON 1 /* non-confirmable message (one-shot message) */
45 #define COAP_MESSAGE_ACK 2 /* used to acknowledge confirmable messages */
46 #define COAP_MESSAGE_RST 3 /* indicates error in received messages */
48 /* CoAP request methods */
50 #define COAP_REQUEST_GET 1
51 #define COAP_REQUEST_POST 2
52 #define COAP_REQUEST_PUT 3
53 #define COAP_REQUEST_DELETE 4
55 /* CoAP option types (be sure to update check_critical when adding options */
57 #define COAP_OPTION_IF_MATCH 1 /* C, opaque, 0-8 B, (none) */
58 #define COAP_OPTION_URI_HOST 3 /* C, String, 1-255 B, destination address */
59 #define COAP_OPTION_ETAG 4 /* E, opaque, 1-8 B, (none) */
60 #define COAP_OPTION_IF_NONE_MATCH 5 /* empty, 0 B, (none) */
61 #define COAP_OPTION_URI_PORT 7 /* C, uint, 0-2 B, destination port */
62 #define COAP_OPTION_LOCATION_PATH 8 /* E, String, 0-255 B, - */
63 #define COAP_OPTION_URI_PATH 11 /* C, String, 0-255 B, (none) */
64 #define COAP_OPTION_CONTENT_FORMAT 12 /* E, uint, 0-2 B, (none) */
65 #define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
66 #define COAP_OPTION_MAXAGE 14 /* E, uint, 0--4 B, 60 Seconds */
67 #define COAP_OPTION_URI_QUERY 15 /* C, String, 1-255 B, (none) */
68 #define COAP_OPTION_ACCEPT 17 /* C, uint, 0-2 B, (none) */
69 #define COAP_OPTION_LOCATION_QUERY 20 /* E, String, 0-255 B, (none) */
70 #define COAP_OPTION_PROXY_URI 35 /* C, String, 1-1034 B, (none) */
71 #define COAP_OPTION_PROXY_SCHEME 39 /* C, String, 1-255 B, (none) */
72 #define COAP_OPTION_SIZE1 60 /* E, uint, 0-4 B, (none) */
74 /* option types from draft-ietf-coap-observe-09 */
76 #define COAP_OPTION_OBSERVE 6 /* E, empty/uint, 0 B/0-3 B, (none) */
77 #define COAP_OPTION_SUBSCRIPTION COAP_OPTION_OBSERVE
79 /* selected option types from draft-core-block-04 */
81 #define COAP_OPTION_BLOCK2 23 /* C, uint, 0--3 B, (none) */
82 #define COAP_OPTION_BLOCK1 27 /* C, uint, 0--3 B, (none) */
84 #define COAP_MAX_OPT 63 /**< the highest option number we know */
86 /* CoAP result codes (HTTP-Code / 100 * 40 + HTTP-Code % 100) */
88 /* As of draft-ietf-core-coap-04, response codes are encoded to base
89 * 32, i.e. the three upper bits determine the response class while
90 * the remaining five fine-grained information specific to that class.
92 #define COAP_RESPONSE_CODE(N) (((N)/100 << 5) | (N)%100)
94 /* Determines the class of response code C */
95 #define COAP_RESPONSE_CLASS(C) (((C) >> 5) & 0xFF)
97 #ifndef SHORT_ERROR_RESPONSE
99 * Returns a human-readable response phrase for the specified CoAP
100 * response @p code. This function returns @c NULL if not found.
102 * @param code The response code for which the literal phrase should
105 * @return A zero-terminated string describing the error, or @c NULL
108 char *coap_response_phrase(unsigned char code);
110 #define COAP_ERROR_PHRASE_LENGTH 32 /**< maximum length of error phrase */
113 #define coap_response_phrase(x) ((char *)NULL)
115 #define COAP_ERROR_PHRASE_LENGTH 0 /**< maximum length of error phrase */
116 #endif /* SHORT_ERROR_RESPONSE */
118 /* The following definitions exist for backwards compatibility */
119 #if 0 /* this does not exist any more */
120 #define COAP_RESPONSE_100 40 /* 100 Continue */
122 #define COAP_RESPONSE_200 COAP_RESPONSE_CODE(200) /* 2.00 OK */
123 #define COAP_RESPONSE_201 COAP_RESPONSE_CODE(201) /* 2.01 Created */
124 #define COAP_RESPONSE_304 COAP_RESPONSE_CODE(203) /* 2.03 Valid */
125 #define COAP_RESPONSE_400 COAP_RESPONSE_CODE(400) /* 4.00 Bad Request */
126 #define COAP_RESPONSE_404 COAP_RESPONSE_CODE(404) /* 4.04 Not Found */
127 #define COAP_RESPONSE_405 COAP_RESPONSE_CODE(405) /* 4.05 Method Not Allowed */
128 #define COAP_RESPONSE_415 COAP_RESPONSE_CODE(415) /* 4.15 Unsupported Media Type */
129 #define COAP_RESPONSE_500 COAP_RESPONSE_CODE(500) /* 5.00 Internal Server Error */
130 #define COAP_RESPONSE_501 COAP_RESPONSE_CODE(501) /* 5.01 Not Implemented */
131 #define COAP_RESPONSE_503 COAP_RESPONSE_CODE(503) /* 5.03 Service Unavailable */
132 #define COAP_RESPONSE_504 COAP_RESPONSE_CODE(504) /* 5.04 Gateway Timeout */
133 #if 0 /* these response codes do not have a valid code any more */
134 # define COAP_RESPONSE_X_240 240 /* Token Option required by server */
135 # define COAP_RESPONSE_X_241 241 /* Uri-Authority Option required by server */
137 #define COAP_RESPONSE_X_242 COAP_RESPONSE_CODE(402) /* Critical Option not supported */
139 /* CoAP media type encoding */
141 #define COAP_MEDIATYPE_TEXT_PLAIN 0 /* text/plain (UTF-8) */
142 #define COAP_MEDIATYPE_APPLICATION_LINK_FORMAT 40 /* application/link-format */
143 #define COAP_MEDIATYPE_APPLICATION_XML 41 /* application/xml */
144 #define COAP_MEDIATYPE_APPLICATION_OCTET_STREAM 42 /* application/octet-stream */
145 #define COAP_MEDIATYPE_APPLICATION_RDF_XML 43 /* application/rdf+xml */
146 #define COAP_MEDIATYPE_APPLICATION_EXI 47 /* application/exi */
147 #define COAP_MEDIATYPE_APPLICATION_JSON 50 /* application/json */
149 /* Note that identifiers for registered media types are in the range 0-65535. We
150 * use an unallocated type here and hope for the best. */
151 #define COAP_MEDIATYPE_ANY 0xff /* any media type */
153 /* CoAP transaction id */
154 /*typedef unsigned short coap_tid_t; */
155 typedef int coap_tid_t;
156 #define COAP_INVALID_TID -1
158 #ifdef WORDS_BIGENDIAN
161 unsigned int version:2; /* protocol version */
162 unsigned int type:2; /* type flag */
163 unsigned int token_length:4; /* length of Token */
164 unsigned int code:8; /* request method (value 1--10) or response code (value 40-255) */
165 unsigned short id; /* message id */
166 unsigned char token[]; /* the actual token, if any */
171 unsigned int token_length :4; /* length of Token */
172 unsigned int type :2; /* type flag */
173 unsigned int version :2; /* protocol version */
174 unsigned int code :8; /* request method (value 1--10) or response code (value 40-255) */
175 unsigned short id; /* transaction id (network byte order!) */
176 unsigned char token[]; /* the actual token, if any */
180 #define COAP_MESSAGE_IS_EMPTY(MSG) ((MSG)->code == 0)
181 #define COAP_MESSAGE_IS_REQUEST(MSG) (!COAP_MESSAGE_IS_EMPTY(MSG) \
182 && ((MSG)->code < 32))
183 #define COAP_MESSAGE_IS_RESPONSE(MSG) ((MSG)->code >= 64 && (MSG)->code <= 191)
185 #define COAP_OPT_LONG 0x0F /* OC == 0b1111 indicates that the option list in a
186 * CoAP message is limited by 0b11110000 marker */
188 #define COAP_OPT_END 0xF0 /* end marker */
190 #define COAP_PAYLOAD_START 0xFF /* payload marker */
193 * Structures for more convenient handling of options. (To be used with ordered
194 * coap_list_t.) The option's data will be added to the end of the coap_option
195 * structure (see macro COAP_OPTION_DATA).
199 unsigned short key; /* the option key (no delta coding) */
203 #define COAP_OPTION_KEY(option) (option).key
204 #define COAP_OPTION_LENGTH(option) (option).length
205 #define COAP_OPTION_DATA(option) ((unsigned char *)&(option) + sizeof(coap_option))
207 /** Header structure for CoAP PDUs */
211 size_t max_size; /**< allocated storage for options and data */
214 unsigned short max_delta; /**< highest option number */
215 unsigned short length; /**< PDU length (including header, options, data) */
216 unsigned char *data; /**< payload */
219 struct pbuf *pbuf; /**< lwIP PBUF. The allocated coap_pdu_t will always reside inside the pbuf's payload, but the 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. */
224 /** Options in coap_pdu_t are accessed with the macro COAP_OPTION. */
225 #define COAP_OPTION(node) ((coap_option *)(node)->options)
229 * Creates a CoAP PDU from an lwIP @p pbuf, whose reference is passed on to
232 * The pbuf is checked for being contiguous, for having enough head space for
233 * the PDU struct (which is located directly in front of the data, overwriting
234 * the old other headers), and for having only one reference. The reference is
235 * stored in the PDU and will be freed when the PDU is freed.
237 * (For now, these are errors; in future, a new pbuf might be allocated, the
238 * data copied and the passed pbuf freed).
240 * This behaves like coap_pdu_init(0, 0, 0, pbuf->tot_len), and afterwards
241 * copying the contents of the pbuf to the pdu.
243 * @return A pointer to the new PDU object or @c NULL on error.
245 coap_pdu_t * coap_pdu_from_pbuf(struct pbuf *pbuf);
249 * Creates a new CoAP PDU of given @p size (must be large enough to hold the
250 * basic CoAP message header (coap_hdr_t). The function returns a pointer to
251 * the node coap_pdu_t object on success, or @c NULL on error. The storage
252 * allocated for the result must be released with coap_delete_pdu().
254 * @param type The type of the PDU (one of COAP_MESSAGE_CON,
255 * COAP_MESSAGE_NON, COAP_MESSAGE_ACK, COAP_MESSAGE_RST).
256 * @param code The message code.
257 * @param id The message id to set or COAP_INVALID_TID if unknown.
258 * @param size The number of bytes to allocate for the actual message.
260 * @return A pointer to the new PDU object or @c NULL on error.
263 coap_pdu_init(unsigned char type, unsigned char code, unsigned short id, size_t size);
266 * Clears any contents from @p pdu and resets @c version field, @c
267 * length and @c data pointers. @c max_size is set to @p size, any
268 * other field is set to @c 0. Note that @p pdu must be a valid
269 * pointer to a coap_pdu_t object created e.g. by coap_pdu_init().
271 void coap_pdu_clear(coap_pdu_t *pdu, size_t size);
274 * Creates a new CoAP PDU. The object is created on the heap and must be released
275 * using coap_delete_pdu();
277 * @deprecated This function allocates the maximum storage for each
278 * PDU. Use coap_pdu_init() instead.
280 coap_pdu_t *coap_new_pdu();
282 void coap_delete_pdu(coap_pdu_t *);
285 * Parses @p data into the CoAP PDU structure given in @p result. This
286 * function returns @c 0 on error or a number greater than zero on
289 * @param data The raw data to parse as CoAP PDU
290 * @param length The actual size of @p data
291 * @param result The PDU structure to fill. Note that the structure must
292 * provide space for at least @p length bytes to hold the
294 * @return A value greater than zero on success or @c 0 on error.
296 int coap_pdu_parse(unsigned char *data, size_t length, coap_pdu_t *result);
299 * Adds token of length @p len to @p pdu. Adding the token destroys
300 * any following contents of the pdu. Hence options and data must be
301 * added after coap_add_token() has been called. In @p pdu, length is
302 * set to @p len + @c 4, and max_delta is set to @c 0. This funtion
303 * returns @c 0 on error or a value greater than zero on success.
305 * @param pdu The PDU where the token is to be added.
306 * @param len The length of the new token.
307 * @param data The token to add.
308 * @return A value greater than zero on success, or @c 0 on error.
310 int coap_add_token(coap_pdu_t *pdu, size_t len, const unsigned char *data);
313 * Adds option of given type to pdu that is passed as first
314 * parameter. coap_add_option() destroys the PDU's data, so
315 * coap_add_data() must be called after all options have been added.
316 * As coap_add_token() destroys the options following the token,
317 * the token must be added before coap_add_option() is called.
318 * This function returns the number of bytes written or @c 0 on error.
320 size_t coap_add_option(coap_pdu_t *pdu, unsigned short type, unsigned int len,
321 const unsigned char *data);
324 * Adds option of given type to pdu that is passed as first
325 * parameter, but does not write a value. It works like coap_add_option with
326 * respect to calling sequence (i.e. after token and before data).
327 * This function returns a memory address to which the option data has to be
328 * written before the PDU can be sent, or @c NULL on error.
330 unsigned char *coap_add_option_later(coap_pdu_t *pdu, unsigned short type, unsigned int len);
333 * Adds given data to the pdu that is passed as first parameter. Note
334 * that the PDU's data is destroyed by coap_add_option(). coap_add_data()
335 * must be called only once per PDU, otherwise the result is undefined.
337 int coap_add_data(coap_pdu_t *pdu, unsigned int len, const unsigned char *data);
340 * Retrieves the length and data pointer of specified PDU. Returns 0 on error
341 * or 1 if *len and *data have correct values. Note that these values are
342 * destroyed with the pdu.
344 int coap_get_data(coap_pdu_t *pdu, size_t *len, unsigned char **data);