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1 /*
2  * coap_pdu.h -- CoAP message structure
3  *
4  * Copyright (C) 2010-2014 Olaf Bergmann <bergmann@tzi.org>
5  * Copyright (C) 2021-2023 Jon Shallow <supjps-libcoap@jpshallow.com>
6  *
7  * SPDX-License-Identifier: BSD-2-Clause
8  *
9  * This file is part of the CoAP library libcoap. Please see README for terms
10  * of use.
11  */
12 
13 /**
14  * @file coap_pdu.h
15  * @brief Pre-defined constants that reflect defaults for CoAP
16  */
17 
18 #ifndef COAP_PDU_H_
19 #define COAP_PDU_H_
20 
21 #include "coap_option.h"
22 #include "coap_uri.h"
23 
24 #ifdef WITH_LWIP
25 #include <lwip/pbuf.h>
26 #endif
27 
28 #include <stdint.h>
29 
30 /**
31  * @ingroup application_api
32  * @defgroup pdu PDU
33  * API for PDUs
34  * @{
35  */
36 
37  #ifndef COAP_USER_DEFAULT_PORT
38  #define COAP_USER_DEFAULT_PORT 5683 /* CoAP default UDP/TCP port */
39  #endif
40  #define COAP_DEFAULT_PORT COAP_USER_DEFAULT_PORT
41 
42 #define COAPS_DEFAULT_PORT     5684 /* CoAP default UDP/TCP port for secure transmission */
43 #define COAP_DEFAULT_MAX_AGE     60 /* default maximum object lifetime in seconds */
44 #ifndef COAP_DEFAULT_MTU
45 #define COAP_DEFAULT_MTU       1152
46 #endif /* COAP_DEFAULT_MTU */
47 
48 #define COAP_BERT_BASE 1152
49 
50 #ifndef COAP_DEFAULT_HOP_LIMIT
51 #define COAP_DEFAULT_HOP_LIMIT       16
52 #endif /* COAP_DEFAULT_HOP_LIMIT */
53 
54 #define COAP_DEFAULT_SCHEME  "coap" /* the default scheme for CoAP URIs */
55 
56 /** well-known resources URI */
57 #define COAP_DEFAULT_URI_WELLKNOWN ".well-known/core"
58 
59 /* Extended Token constants */
60 #define COAP_TOKEN_DEFAULT_MAX 8
61 #define COAP_TOKEN_EXT_MAX 65804 /* 13 + 256 + 65535 */
62 
63 /* CoAP message types */
64 
65 /**
66  * CoAP PDU message type definitions
67  */
68 typedef enum coap_pdu_type_t {
69   COAP_MESSAGE_CON,  /* 0 confirmable message (requires ACK/RST) */
70   COAP_MESSAGE_NON,  /* 1 non-confirmable message (one-shot message) */
71   COAP_MESSAGE_ACK,  /* 2 used to acknowledge confirmable messages */
72   COAP_MESSAGE_RST   /* 3 indicates error in received messages */
73 } coap_pdu_type_t;
74 
75 /**
76  * CoAP PDU Request methods
77  */
78 typedef enum coap_request_t {
79   COAP_REQUEST_GET = 1,
80   COAP_REQUEST_POST,      /* 2 */
81   COAP_REQUEST_PUT,       /* 3 */
82   COAP_REQUEST_DELETE,    /* 4 */
83   COAP_REQUEST_FETCH,     /* 5 RFC 8132 */
84   COAP_REQUEST_PATCH,     /* 6 RFC 8132 */
85   COAP_REQUEST_IPATCH,    /* 7 RFC 8132 */
86 } coap_request_t;
87 
88 /*
89  * CoAP option numbers (be sure to update coap_option_check_critical() and
90  * coap_add_option() when adding options
91  */
92 
93 /*
94  * The C, U, and N flags indicate the properties
95  * Critical, Unsafe, and NoCacheKey, respectively.
96  * If U is set, then N has no meaning as per
97  * https://rfc-editor.org/rfc/rfc7252#section-5.10
98  * and is set to a -.
99  *
100  * Separately, R is for the options that can be repeated
101  *
102  * The least significant byte of the option is set as followed
103  * as per https://rfc-editor.org/rfc/rfc7252#section-5.4.6
104  *
105  *   0   1   2   3   4   5   6   7
106  * --+---+---+---+---+---+---+---+
107  *           | NoCacheKey| U | C |
108  * --+---+---+---+---+---+---+---+
109  *
110  * https://rfc-editor.org/rfc/rfc8613#section-4 goes on to define E, I and U
111  * properties Encrypted and Integrity Protected, Integrity Protected Only, and
112  * Unprotected respectively.  Integrity Protected Only is not currently used.
113  *
114  * An Option is tagged with CUNREIU with any of the letters replaced with _ if
115  * not set, or - for N if U is set (see above) for aiding understanding of the
116  * Option.
117  */
118 
119 #define COAP_OPTION_IF_MATCH        1 /* C__RE__, opaque,    0-8 B, RFC7252 */
120 #define COAP_OPTION_URI_HOST        3 /* CU-___U, String,  1-255 B, RFC7252 */
121 #define COAP_OPTION_ETAG            4 /* ___RE__, opaque,    1-8 B, RFC7252 */
122 #define COAP_OPTION_IF_NONE_MATCH   5 /* C___E__, empty,       0 B, RFC7252 */
123 #define COAP_OPTION_OBSERVE         6 /* _U-_E_U, empty/uint,0/0-3 B, RFC7641 */
124 #define COAP_OPTION_URI_PORT        7 /* CU-___U, uint,      0-2 B, RFC7252 */
125 #define COAP_OPTION_LOCATION_PATH   8 /* ___RE__, String,  0-255 B, RFC7252 */
126 #define COAP_OPTION_OSCORE          9 /* C_____U, *,       0-255 B, RFC8613 */
127 #define COAP_OPTION_URI_PATH       11 /* CU-RE__, String,  0-255 B, RFC7252 */
128 #define COAP_OPTION_CONTENT_FORMAT 12 /* ____E__, uint,      0-2 B, RFC7252 */
129 #define COAP_OPTION_CONTENT_TYPE COAP_OPTION_CONTENT_FORMAT
130 /* COAP_OPTION_MAXAGE default 60 seconds if not set */
131 #define COAP_OPTION_MAXAGE         14 /* _U-_E_U, uint,      0-4 B, RFC7252 */
132 #define COAP_OPTION_URI_QUERY      15 /* CU-RE__, String,  1-255 B, RFC7252 */
133 #define COAP_OPTION_HOP_LIMIT      16 /* ______U, uint,        1 B, RFC8768 */
134 #define COAP_OPTION_ACCEPT         17 /* C___E__, uint,      0-2 B, RFC7252 */
135 #define COAP_OPTION_Q_BLOCK1       19 /* CU__E_U, uint,      0-3 B, RFC9177 */
136 #define COAP_OPTION_LOCATION_QUERY 20 /* ___RE__, String,  0-255 B, RFC7252 */
137 #define COAP_OPTION_BLOCK2         23 /* CU-_E_U, uint,      0-3 B, RFC7959 */
138 #define COAP_OPTION_BLOCK1         27 /* CU-_E_U, uint,      0-3 B, RFC7959 */
139 #define COAP_OPTION_SIZE2          28 /* __N_E_U, uint,      0-4 B, RFC7959 */
140 #define COAP_OPTION_Q_BLOCK2       31 /* CU_RE_U, uint,      0-3 B, RFC9177 */
141 #define COAP_OPTION_PROXY_URI      35 /* CU-___U, String, 1-1034 B, RFC7252 */
142 #define COAP_OPTION_PROXY_SCHEME   39 /* CU-___U, String,  1-255 B, RFC7252 */
143 #define COAP_OPTION_SIZE1          60 /* __N_E_U, uint,      0-4 B, RFC7252 */
144 #define COAP_OPTION_ECHO          252 /* _N__E_U, opaque,   0-40 B, RFC9175 */
145 #define COAP_OPTION_NORESPONSE    258 /* _U-_E_U, uint,      0-1 B, RFC7967 */
146 #define COAP_OPTION_RTAG          292 /* ___RE_U, opaque,    0-8 B, RFC9175 */
147 
148 #define COAP_MAX_OPT            65535 /**< the highest option number we know */
149 
150 /* CoAP result codes (HTTP-Code / 100 * 40 + HTTP-Code % 100) */
151 
152 /* As of draft-ietf-core-coap-04, response codes are encoded to base
153  * 32, i.e.  the three upper bits determine the response class while
154  * the remaining five fine-grained information specific to that class.
155  */
156 #define COAP_RESPONSE_CODE(N) (((N)/100 << 5) | (N)%100)
157 
158 /* Determines the class of response code C */
159 #define COAP_RESPONSE_CLASS(C) (((C) >> 5) & 0xFF)
160 
161 #ifndef SHORT_ERROR_RESPONSE
162 /**
163  * Returns a human-readable response phrase for the specified CoAP response @p
164  * code. This function returns @c NULL if not found.
165  *
166  * @param code The response code for which the literal phrase should be
167  *             retrieved.
168  *
169  * @return     A zero-terminated string describing the error, or @c NULL if not
170  *             found.
171  */
172 const char *coap_response_phrase(unsigned char code);
173 
174 #define COAP_ERROR_PHRASE_LENGTH   32 /**< maximum length of error phrase */
175 
176 #else
177 #define coap_response_phrase(x) ((char *)NULL)
178 
179 #define COAP_ERROR_PHRASE_LENGTH    0 /**< maximum length of error phrase */
180 #endif /* SHORT_ERROR_RESPONSE */
181 
182 #define COAP_SIGNALING_CODE(N) (((N)/100 << 5) | (N)%100)
183 
184 typedef enum coap_pdu_signaling_proto_t {
185   COAP_SIGNALING_CSM =     COAP_SIGNALING_CODE(701),
186   COAP_SIGNALING_PING =    COAP_SIGNALING_CODE(702),
187   COAP_SIGNALING_PONG =    COAP_SIGNALING_CODE(703),
188   COAP_SIGNALING_RELEASE = COAP_SIGNALING_CODE(704),
189   COAP_SIGNALING_ABORT =   COAP_SIGNALING_CODE(705),
190 } coap_pdu_signaling_proto_t;
191 
192 /* Applies to COAP_SIGNALING_CSM */
193 #define COAP_SIGNALING_OPTION_MAX_MESSAGE_SIZE 2
194 #define COAP_SIGNALING_OPTION_BLOCK_WISE_TRANSFER 4
195 #define COAP_SIGNALING_OPTION_EXTENDED_TOKEN_LENGTH 6
196 
197 /* Applies to COAP_SIGNALING_PING / COAP_SIGNALING_PONG */
198 #define COAP_SIGNALING_OPTION_CUSTODY 2
199 
200 /* Applies to COAP_SIGNALING_RELEASE */
201 #define COAP_SIGNALING_OPTION_ALTERNATIVE_ADDRESS 2
202 #define COAP_SIGNALING_OPTION_HOLD_OFF 4
203 
204 /* Applies to COAP_SIGNALING_ABORT */
205 #define COAP_SIGNALING_OPTION_BAD_CSM_OPTION 2
206 
207 /* CoAP media type encoding */
208 
209 #define COAP_MEDIATYPE_TEXT_PLAIN                 0 /* text/plain (UTF-8) */
210 #define COAP_MEDIATYPE_APPLICATION_LINK_FORMAT   40 /* application/link-format */
211 #define COAP_MEDIATYPE_APPLICATION_XML           41 /* application/xml */
212 #define COAP_MEDIATYPE_APPLICATION_OCTET_STREAM  42 /* application/octet-stream */
213 #define COAP_MEDIATYPE_APPLICATION_RDF_XML       43 /* application/rdf+xml */
214 #define COAP_MEDIATYPE_APPLICATION_EXI           47 /* application/exi  */
215 #define COAP_MEDIATYPE_APPLICATION_JSON          50 /* application/json  */
216 #define COAP_MEDIATYPE_APPLICATION_CBOR          60 /* application/cbor  */
217 #define COAP_MEDIATYPE_APPLICATION_CWT           61 /* application/cwt, RFC 8392  */
218 
219 /* Content formats from RFC 7390 */
220 #define COAP_MEDIATYPE_APPLICATION_COAP_GROUP_JSON 256 /* application/coap-group+json */
221 
222 /* Content formats from RFC 8152 */
223 #define COAP_MEDIATYPE_APPLICATION_COSE_SIGN     98 /* application/cose; cose-type="cose-sign"     */
224 #define COAP_MEDIATYPE_APPLICATION_COSE_SIGN1    18 /* application/cose; cose-type="cose-sign1"    */
225 #define COAP_MEDIATYPE_APPLICATION_COSE_ENCRYPT  96 /* application/cose; cose-type="cose-encrypt"  */
226 #define COAP_MEDIATYPE_APPLICATION_COSE_ENCRYPT0 16 /* application/cose; cose-type="cose-encrypt0" */
227 #define COAP_MEDIATYPE_APPLICATION_COSE_MAC      97 /* application/cose; cose-type="cose-mac"      */
228 #define COAP_MEDIATYPE_APPLICATION_COSE_MAC0     17 /* application/cose; cose-type="cose-mac0"     */
229 
230 #define COAP_MEDIATYPE_APPLICATION_COSE_KEY     101 /* application/cose-key  */
231 #define COAP_MEDIATYPE_APPLICATION_COSE_KEY_SET 102 /* application/cose-key-set  */
232 
233 /* Content formats from RFC 8428 */
234 #define COAP_MEDIATYPE_APPLICATION_SENML_JSON   110 /* application/senml+json  */
235 #define COAP_MEDIATYPE_APPLICATION_SENSML_JSON  111 /* application/sensml+json */
236 #define COAP_MEDIATYPE_APPLICATION_SENML_CBOR   112 /* application/senml+cbor  */
237 #define COAP_MEDIATYPE_APPLICATION_SENSML_CBOR  113 /* application/sensml+cbor */
238 #define COAP_MEDIATYPE_APPLICATION_SENML_EXI    114 /* application/senml-exi   */
239 #define COAP_MEDIATYPE_APPLICATION_SENSML_EXI   115 /* application/sensml-exi  */
240 #define COAP_MEDIATYPE_APPLICATION_SENML_XML    310 /* application/senml+xml   */
241 #define COAP_MEDIATYPE_APPLICATION_SENSML_XML   311 /* application/sensml+xml  */
242 
243 /* Content formats from RFC 8782 */
244 #define COAP_MEDIATYPE_APPLICATION_DOTS_CBOR    271 /* application/dots+cbor */
245 
246 /* Content formats from RFC 9200 */
247 #define COAP_MEDIATYPE_APPLICATION_ACE_CBOR      19 /* application/ace+cbor  */
248 
249 /* Content formats from RFC9177 */
250 #define COAP_MEDIATYPE_APPLICATION_MB_CBOR_SEQ  272 /* application/missing-blocks+cbor-seq */
251 
252 /* Content formats from RFC 8613 */
253 #define COAP_MEDIATYPE_APPLICATION_OSCORE     10001 /* application/oscore */
254 
255 /**
256  * coap_mid_t is used to store the CoAP Message ID of a CoAP PDU.
257  * Valid message ids are 0 to 2^16.  Negative values are error codes.
258  */
259 typedef int coap_mid_t;
260 
261 /** Indicates an invalid message id. */
262 #define COAP_INVALID_MID -1
263 
264 /**
265  * Indicates an invalid message id.
266  * @deprecated Use COAP_INVALID_MID instead.
267  */
268 #define COAP_INVALID_TID COAP_INVALID_MID
269 
270 /**
271  * @deprecated Use coap_optlist_t instead.
272  *
273  * Structures for more convenient handling of options. (To be used with ordered
274  * coap_list_t.) The option's data will be added to the end of the coap_option
275  * structure (see macro COAP_OPTION_DATA).
276  */
277 COAP_DEPRECATED typedef struct {
278   uint16_t key;           /* the option key (no delta coding) */
279   unsigned int length;
280 } coap_option;
281 
282 #define COAP_OPTION_KEY(option) (option).key
283 #define COAP_OPTION_LENGTH(option) (option).length
284 #define COAP_OPTION_DATA(option) ((unsigned char *)&(option) + sizeof(coap_option))
285 
286 #ifdef WITH_LWIP
287 /**
288  * Creates a CoAP PDU from an lwIP @p pbuf, whose reference is passed on to this
289  * function.
290  *
291  * The pbuf is checked for being contiguous, and for having only one reference.
292  * The reference is stored in the PDU and will be freed when the PDU is freed.
293  *
294  * (For now, these are fatal errors; in future, a new pbuf might be allocated,
295  * the data copied and the passed pbuf freed).
296  *
297  * This behaves like coap_pdu_init(0, 0, 0, pbuf->tot_len), and afterwards
298  * copying the contents of the pbuf to the pdu.
299  *
300  * @return A pointer to the new PDU object or @c NULL on error.
301  */
302 coap_pdu_t *coap_pdu_from_pbuf(struct pbuf *pbuf);
303 #endif
304 
305 /**
306 * CoAP protocol types
307 */
308 typedef enum coap_proto_t {
309   COAP_PROTO_NONE = 0,
310   COAP_PROTO_UDP,
311   COAP_PROTO_DTLS,
312   COAP_PROTO_TCP,
313   COAP_PROTO_TLS,
314   COAP_PROTO_WS,
315   COAP_PROTO_WSS,
316   COAP_PROTO_LAST
317 } coap_proto_t;
318 
319 /**
320  * Set of codes available for a PDU.
321  */
322 typedef enum coap_pdu_code_t {
323   COAP_EMPTY_CODE          = 0,
324 
325   COAP_REQUEST_CODE_GET    = COAP_REQUEST_GET,
326   COAP_REQUEST_CODE_POST   = COAP_REQUEST_POST,
327   COAP_REQUEST_CODE_PUT    = COAP_REQUEST_PUT,
328   COAP_REQUEST_CODE_DELETE = COAP_REQUEST_DELETE,
329   COAP_REQUEST_CODE_FETCH  = COAP_REQUEST_FETCH,
330   COAP_REQUEST_CODE_PATCH  = COAP_REQUEST_PATCH,
331   COAP_REQUEST_CODE_IPATCH = COAP_REQUEST_IPATCH,
332 
333   COAP_RESPONSE_CODE_CREATED                    = COAP_RESPONSE_CODE(201),
334   COAP_RESPONSE_CODE_DELETED                    = COAP_RESPONSE_CODE(202),
335   COAP_RESPONSE_CODE_VALID                      = COAP_RESPONSE_CODE(203),
336   COAP_RESPONSE_CODE_CHANGED                    = COAP_RESPONSE_CODE(204),
337   COAP_RESPONSE_CODE_CONTENT                    = COAP_RESPONSE_CODE(205),
338   COAP_RESPONSE_CODE_CONTINUE                   = COAP_RESPONSE_CODE(231),
339   COAP_RESPONSE_CODE_BAD_REQUEST                = COAP_RESPONSE_CODE(400),
340   COAP_RESPONSE_CODE_UNAUTHORIZED               = COAP_RESPONSE_CODE(401),
341   COAP_RESPONSE_CODE_BAD_OPTION                 = COAP_RESPONSE_CODE(402),
342   COAP_RESPONSE_CODE_FORBIDDEN                  = COAP_RESPONSE_CODE(403),
343   COAP_RESPONSE_CODE_NOT_FOUND                  = COAP_RESPONSE_CODE(404),
344   COAP_RESPONSE_CODE_NOT_ALLOWED                = COAP_RESPONSE_CODE(405),
345   COAP_RESPONSE_CODE_NOT_ACCEPTABLE             = COAP_RESPONSE_CODE(406),
346   COAP_RESPONSE_CODE_INCOMPLETE                 = COAP_RESPONSE_CODE(408),
347   COAP_RESPONSE_CODE_CONFLICT                   = COAP_RESPONSE_CODE(409),
348   COAP_RESPONSE_CODE_PRECONDITION_FAILED        = COAP_RESPONSE_CODE(412),
349   COAP_RESPONSE_CODE_REQUEST_TOO_LARGE          = COAP_RESPONSE_CODE(413),
350   COAP_RESPONSE_CODE_UNSUPPORTED_CONTENT_FORMAT = COAP_RESPONSE_CODE(415),
351   COAP_RESPONSE_CODE_UNPROCESSABLE              = COAP_RESPONSE_CODE(422),
352   COAP_RESPONSE_CODE_TOO_MANY_REQUESTS          = COAP_RESPONSE_CODE(429),
353   COAP_RESPONSE_CODE_INTERNAL_ERROR             = COAP_RESPONSE_CODE(500),
354   COAP_RESPONSE_CODE_NOT_IMPLEMENTED            = COAP_RESPONSE_CODE(501),
355   COAP_RESPONSE_CODE_BAD_GATEWAY                = COAP_RESPONSE_CODE(502),
356   COAP_RESPONSE_CODE_SERVICE_UNAVAILABLE        = COAP_RESPONSE_CODE(503),
357   COAP_RESPONSE_CODE_GATEWAY_TIMEOUT            = COAP_RESPONSE_CODE(504),
358   COAP_RESPONSE_CODE_PROXYING_NOT_SUPPORTED     = COAP_RESPONSE_CODE(505),
359   COAP_RESPONSE_CODE_HOP_LIMIT_REACHED          = COAP_RESPONSE_CODE(508),
360 
361   COAP_SIGNALING_CODE_CSM                       = COAP_SIGNALING_CSM,
362   COAP_SIGNALING_CODE_PING                      = COAP_SIGNALING_PING,
363   COAP_SIGNALING_CODE_PONG                      = COAP_SIGNALING_PONG,
364   COAP_SIGNALING_CODE_RELEASE                   = COAP_SIGNALING_RELEASE,
365   COAP_SIGNALING_CODE_ABORT                     = COAP_SIGNALING_ABORT
366 } coap_pdu_code_t;
367 
368 /**
369  * Creates a new CoAP PDU with at least enough storage space for the given
370  * @p size maximum message size. The function returns a pointer to the
371  * node coap_pdu_t object on success, or @c NULL on error. The storage allocated
372  * for the result must be released with coap_delete_pdu() if coap_send()
373  * is not called.
374  *
375  * @param type The type of the PDU (one of COAP_MESSAGE_CON, COAP_MESSAGE_NON,
376  *             COAP_MESSAGE_ACK, COAP_MESSAGE_RST).
377  * @param code The message code of the PDU.
378  * @param mid  The message id to set or 0 if unknown / not applicable.
379  * @param size The maximum allowed number of byte for the message.
380  * @return     A pointer to the new PDU object or @c NULL on error.
381  */
382 coap_pdu_t *coap_pdu_init(coap_pdu_type_t type, coap_pdu_code_t code,
383                           coap_mid_t mid, size_t size);
384 
385 /**
386  * Creates a new CoAP PDU.
387  *
388  * @param type The type of the PDU (one of COAP_MESSAGE_CON, COAP_MESSAGE_NON,
389  *             COAP_MESSAGE_ACK, COAP_MESSAGE_RST).
390  * @param code The message code of the PDU.
391  * @param session The session that will be using this PDU
392  *
393  * @return The skeletal PDU or @c NULL if failure.
394  */
395 coap_pdu_t *coap_new_pdu(coap_pdu_type_t type, coap_pdu_code_t code,
396                          coap_session_t *session);
397 
398 /**
399  * Dispose of an CoAP PDU and frees associated storage.
400  * Not that in general you should not call this function directly.
401  * When a PDU is sent with coap_send(), coap_delete_pdu() will be called
402  * automatically for you.
403  *
404  * @param pdu The PDU for free off.
405  */
406 void coap_delete_pdu(coap_pdu_t *pdu);
407 
408 /**
409  * Duplicate an existing PDU. Specific options can be ignored and not copied
410  * across.  The PDU data payload is not copied across.
411  *
412  * @param old_pdu      The PDU to duplicate
413  * @param session      The session that will be using this PDU.
414  * @param token_length The length of the token to use in this duplicated PDU.
415  * @param token        The token to use in this duplicated PDU.
416  * @param drop_options A list of options not to copy into the duplicated PDU.
417  *                     If @c NULL, then all options are copied across.
418  *
419  * @return The duplicated PDU or @c NULL if failure.
420  */
421 coap_pdu_t *coap_pdu_duplicate(const coap_pdu_t *old_pdu,
422                                coap_session_t *session,
423                                size_t token_length,
424                                const uint8_t *token,
425                                coap_opt_filter_t *drop_options);
426 
427 /**
428  * Parses @p data into the CoAP PDU structure given in @p result.
429  * The target pdu must be large enough to hold the token, options and data.
430  * This function returns @c 0 on error or a number greater than zero on success.
431  *
432  * @param proto   Session's protocol
433  * @param data    The raw data to parse as CoAP PDU.
434  * @param length  The actual size of @p data.
435  * @param pdu     The PDU structure to fill. Note that the structure must
436  *                provide space to hold the token, optional options and
437  *                optional data.
438  *
439  * @return       1 on success or @c 0 on error.
440  */
441 int coap_pdu_parse(coap_proto_t proto,
442                    const uint8_t *data,
443                    size_t length,
444                    coap_pdu_t *pdu);
445 
446 /**
447  * Adds token of length @p len to @p pdu.
448  *
449  * This function will fail if a token has already been added to the @p pdu.
450  *
451  * Hence options and data must be added after optional coap_add_token() has
452  * been called.
453  *
454  * @param pdu  The PDU where the token is to be added.
455  * @param len  The length of the new token.
456  * @param data The token to add.
457  *
458  * @return     A value greater than zero on success, or @c 0 on error.
459  */
460 int coap_add_token(coap_pdu_t *pdu,
461                    size_t len,
462                    const uint8_t *data);
463 
464 /**
465  * Adds option of given @p number to @p pdu that is passed as first
466  * parameter.
467  *
468  * This function will fail if data has already been added to the @p pdu.
469  *
470  * Hence data must be added after optional coap_add_option() has been called.
471  *
472  * Note: Where possible, the option data needs to be stripped of leading zeros
473  * (big endian) to reduce the amount of data needed in the PDU, as well as in
474  * some cases the maximum data size of an opton can be exceeded if not stripped
475  * and hence be illegal.  This is done by using coap_encode_var_safe() or
476  * coap_encode_var_safe8().
477  *
478  * @param pdu    The PDU where the option is to be added.
479  * @param number The number of the new option.
480  * @param len    The length of the new option.
481  * @param data   The data of the new option.
482  *
483  * @return The overall length of the option or @c 0 on failure.
484  */
485 size_t coap_add_option(coap_pdu_t *pdu,
486                        coap_option_num_t number,
487                        size_t len,
488                        const uint8_t *data);
489 
490 /**
491  * Adds given data to the pdu that is passed as first parameter.
492  *
493  * This function will fail if data has already been added to the @p pdu.
494  *
495  * @param pdu    The PDU where the data is to be added.
496  * @param len    The length of the data.
497  * @param data   The data to add.
498  *
499  * @return @c 1 if success, else @c 0 if failure.
500  */
501 int coap_add_data(coap_pdu_t *pdu,
502                   size_t len,
503                   const uint8_t *data);
504 
505 /**
506  * Adds given data to the pdu that is passed as first parameter but does not
507  *
508  * This function will fail if data has already been added to the @p pdu.
509  *
510  * The actual data must be copied at the returned location.
511  *
512  * @param pdu    The PDU where the data is to be added.
513  * @param len    The length of the data.
514  *
515  * @return Where to copy the data of len to, or @c NULL is error.
516  */
517 uint8_t *coap_add_data_after(coap_pdu_t *pdu, size_t len);
518 
519 /**
520  * Retrieves the length and data pointer of specified PDU. Returns 0 on error or
521  * 1 if *len and *data have correct values. Note that these values are destroyed
522  * with the pdu.
523  *
524  * @param pdu    The specified PDU.
525  * @param len    Returns the length of the current data
526  * @param data   Returns the ptr to the current data
527  *
528  * @return @c 1 if len and data are correctly filled in, else
529  *         @c 0 if there is no data.
530  */
531 int coap_get_data(const coap_pdu_t *pdu,
532                   size_t *len,
533                   const uint8_t **data);
534 
535 /**
536  * Retrieves the data from a PDU, with support for large bodies of data that
537  * spans multiple PDUs.
538  *
539  * Note: The data pointed to on return is destroyed when the PDU is destroyed.
540  *
541  * @param pdu    The specified PDU.
542  * @param len    Returns the length of the current data
543  * @param data   Returns the ptr to the current data
544  * @param offset Returns the offset of the current data from the start of the
545  *               body comprising of many blocks (RFC7959)
546  * @param total  Returns the total size of the body.
547  *               If offset + length < total, then there is more data to follow.
548  *
549  * @return @c 1 if len, data, offset and total are correctly filled in, else
550  *         @c 0 if there is no data.
551  */
552 int coap_get_data_large(const coap_pdu_t *pdu,
553                         size_t *len,
554                         const uint8_t **data,
555                         size_t *offset,
556                         size_t *total);
557 
558 /**
559  * Gets the PDU code associated with @p pdu.
560  *
561  * @param pdu The PDU object.
562  *
563  * @return The PDU code.
564  */
565 coap_pdu_code_t coap_pdu_get_code(const coap_pdu_t *pdu);
566 
567 /**
568  * Sets the PDU code in the @p pdu.
569  *
570  * @param pdu The PDU object.
571  * @param code The code to set in the PDU.
572  */
573 void coap_pdu_set_code(coap_pdu_t *pdu, coap_pdu_code_t code);
574 
575 /**
576  * Gets the PDU type associated with @p pdu.
577  *
578  * @param pdu The PDU object.
579  *
580  * @return The PDU type.
581  */
582 coap_pdu_type_t coap_pdu_get_type(const coap_pdu_t *pdu);
583 
584 /**
585  * Sets the PDU type in the @p pdu.
586  *
587  * @param pdu The PDU object.
588  * @param type The type to set for the PDU.
589  */
590 void coap_pdu_set_type(coap_pdu_t *pdu, coap_pdu_type_t type);
591 
592 /**
593  * Gets the token associated with @p pdu.
594  *
595  * @param pdu The PDU object.
596  *
597  * @return The token information.
598  */
599 coap_bin_const_t coap_pdu_get_token(const coap_pdu_t *pdu);
600 
601 /**
602  * Gets the message id associated with @p pdu.
603  *
604  * @param pdu The PDU object.
605  *
606  * @return The message id.
607  */
608 coap_mid_t coap_pdu_get_mid(const coap_pdu_t *pdu);
609 
610 /**
611  * Sets the message id in the @p pdu.
612  *
613  * @param pdu The PDU object.
614  * @param mid The message id value to set in the PDU.
615  *
616  */
617 void coap_pdu_set_mid(coap_pdu_t *pdu, coap_mid_t mid);
618 
619 /** @} */
620 
621 #endif /* COAP_PDU_H_ */
622