1 /* coap_resource.c -- generic resource handling
2 *
3 * Copyright (C) 2010--2023 Olaf Bergmann <bergmann@tzi.org>
4 *
5 * SPDX-License-Identifier: BSD-2-Clause
6 *
7 * This file is part of the CoAP library libcoap. Please see
8 * README for terms of use.
9 */
10
11 /**
12 * @file coap_resource.c
13 * @brief Server resource handling functions
14 */
15
16 #include "coap3/coap_internal.h"
17
18 #if COAP_SERVER_SUPPORT
19 #include <stdio.h>
20
21 #ifdef COAP_EPOLL_SUPPORT
22 #include <sys/epoll.h>
23 #include <sys/timerfd.h>
24 #endif /* COAP_EPOLL_SUPPORT */
25
26 #define COAP_PRINT_STATUS_MAX (~COAP_PRINT_STATUS_MASK)
27
28 #ifndef min
29 #define min(a,b) ((a) < (b) ? (a) : (b))
30 #endif
31
32 /* Helper functions for conditional output of character sequences into
33 * a given buffer. The first Offset characters are skipped.
34 */
35
36 /**
37 * Adds Char to Buf if Offset is zero. Otherwise, Char is not written
38 * and Offset is decremented.
39 */
40 #define PRINT_WITH_OFFSET(Buf,Offset,Char) \
41 if ((Offset) == 0) { \
42 (*(Buf)++) = (Char); \
43 } else { \
44 (Offset)--; \
45 } \
46
47 /**
48 * Adds Char to Buf if Offset is zero and Buf is less than Bufend.
49 */
50 #define PRINT_COND_WITH_OFFSET(Buf,Bufend,Offset,Char,Result) { \
51 if ((Buf) < (Bufend)) { \
52 PRINT_WITH_OFFSET(Buf,Offset,Char); \
53 } \
54 (Result)++; \
55 }
56
57 /**
58 * Copies at most Length characters of Str to Buf. The first Offset
59 * characters are skipped. Output may be truncated to Bufend - Buf
60 * characters.
61 */
62 #define COPY_COND_WITH_OFFSET(Buf,Bufend,Offset,Str,Length,Result) { \
63 size_t i; \
64 for (i = 0; i < (Length); i++) { \
65 PRINT_COND_WITH_OFFSET((Buf), (Bufend), (Offset), (Str)[i], (Result)); \
66 } \
67 }
68
69 static int
match(const coap_str_const_t * text,const coap_str_const_t * pattern,int match_prefix,int match_substring)70 match(const coap_str_const_t *text, const coap_str_const_t *pattern, int match_prefix,
71 int match_substring
72 ) {
73 assert(text);
74 assert(pattern);
75
76 if (text->length < pattern->length)
77 return 0;
78
79 if (match_substring) {
80 const uint8_t *next_token = text->s;
81 size_t remaining_length = text->length;
82 while (remaining_length) {
83 size_t token_length;
84 const uint8_t *token = next_token;
85 next_token = (unsigned char *)memchr(token, ' ', remaining_length);
86
87 if (next_token) {
88 token_length = next_token - token;
89 remaining_length -= (token_length + 1);
90 next_token++;
91 } else {
92 token_length = remaining_length;
93 remaining_length = 0;
94 }
95
96 if ((match_prefix || pattern->length == token_length) &&
97 memcmp(token, pattern->s, pattern->length) == 0)
98 return 1;
99 }
100 return 0;
101 }
102
103 return (match_prefix || pattern->length == text->length) &&
104 memcmp(text->s, pattern->s, pattern->length) == 0;
105 }
106
107 /**
108 * Prints the names of all known resources to @p buf. This function
109 * sets @p buflen to the number of bytes actually written and returns
110 * @c 1 on succes. On error, the value in @p buflen is undefined and
111 * the return value will be @c 0.
112 *
113 * @param context The context with the resource map.
114 * @param buf The buffer to write the result.
115 * @param buflen Must be initialized to the maximum length of @p buf and will be
116 * set to the length of the well-known response on return.
117 * @param offset The offset in bytes where the output shall start and is
118 * shifted accordingly with the characters that have been
119 * processed. This parameter is used to support the block
120 * option.
121 * @param query_filter A filter query according to <a href="http://tools.ietf.org/html/draft-ietf-core-link-format-11#section-4.1">Link Format</a>
122 *
123 * @return COAP_PRINT_STATUS_ERROR on error. Otherwise, the lower 28 bits are
124 * set to the number of bytes that have actually been written to
125 * @p buf. COAP_PRINT_STATUS_TRUNC is set when the output has been
126 * truncated.
127 */
128 #if defined(__GNUC__) && defined(WITHOUT_QUERY_FILTER)
129 coap_print_status_t
coap_print_wellknown(coap_context_t * context,unsigned char * buf,size_t * buflen,size_t offset,const coap_string_t * query_filter COAP_UNUSED)130 coap_print_wellknown(coap_context_t *context, unsigned char *buf, size_t *buflen,
131 size_t offset,
132 const coap_string_t *query_filter COAP_UNUSED) {
133 #else /* not a GCC */
134 coap_print_status_t
135 coap_print_wellknown(coap_context_t *context, unsigned char *buf, size_t *buflen,
136 size_t offset, const coap_string_t *query_filter) {
137 #endif /* GCC */
138 size_t output_length = 0;
139 unsigned char *p = buf;
140 const uint8_t *bufend = buf + *buflen;
141 size_t left, written = 0;
142 coap_print_status_t result;
143 const size_t old_offset = offset;
144 int subsequent_resource = 0;
145 #ifndef WITHOUT_QUERY_FILTER
146 coap_str_const_t resource_param = { 0, NULL }, query_pattern = { 0, NULL };
147 int flags = 0; /* MATCH_SUBSTRING, MATCH_PREFIX, MATCH_URI */
148 #define MATCH_URI 0x01
149 #define MATCH_PREFIX 0x02
150 #define MATCH_SUBSTRING 0x04
151 static const coap_str_const_t _rt_attributes[] = {
152 {2, (const uint8_t *)"rt"},
153 {2, (const uint8_t *)"if"},
154 {3, (const uint8_t *)"rel"},
155 {0, NULL}
156 };
157 #endif /* WITHOUT_QUERY_FILTER */
158
159 #ifndef WITHOUT_QUERY_FILTER
160 /* split query filter, if any */
161 if (query_filter) {
162 resource_param.s = query_filter->s;
163 while (resource_param.length < query_filter->length &&
164 resource_param.s[resource_param.length] != '=')
165 resource_param.length++;
166
167 if (resource_param.length < query_filter->length) {
168 const coap_str_const_t *rt_attributes;
169 if (resource_param.length == 4 &&
170 memcmp(resource_param.s, "href", 4) == 0)
171 flags |= MATCH_URI;
172
173 for (rt_attributes = _rt_attributes; rt_attributes->s; rt_attributes++) {
174 if (resource_param.length == rt_attributes->length &&
175 memcmp(resource_param.s, rt_attributes->s, rt_attributes->length) == 0) {
176 flags |= MATCH_SUBSTRING;
177 break;
178 }
179 }
180
181 /* rest is query-pattern */
182 query_pattern.s =
183 query_filter->s + resource_param.length + 1;
184
185 assert((resource_param.length + 1) <= query_filter->length);
186 query_pattern.length =
187 query_filter->length - (resource_param.length + 1);
188
189 if ((query_pattern.s[0] == '/') && ((flags & MATCH_URI) == MATCH_URI)) {
190 query_pattern.s++;
191 query_pattern.length--;
192 }
193
194 if (query_pattern.length &&
195 query_pattern.s[query_pattern.length-1] == '*') {
196 query_pattern.length--;
197 flags |= MATCH_PREFIX;
198 }
199 }
200 }
201 #endif /* WITHOUT_QUERY_FILTER */
202
203 RESOURCES_ITER(context->resources, r) {
204
205 #ifndef WITHOUT_QUERY_FILTER
206 if (resource_param.length) { /* there is a query filter */
207
208 if (flags & MATCH_URI) { /* match resource URI */
209 if (!match(r->uri_path, &query_pattern, (flags & MATCH_PREFIX) != 0,
210 (flags & MATCH_SUBSTRING) != 0))
211 continue;
212 } else { /* match attribute */
213 coap_attr_t *attr;
214 coap_str_const_t unquoted_val;
215 attr = coap_find_attr(r, &resource_param);
216 if (!attr || !attr->value)
217 continue;
218 unquoted_val = *attr->value;
219 if (attr->value->s[0] == '"') { /* if attribute has a quoted value, remove double quotes */
220 unquoted_val.length -= 2;
221 unquoted_val.s += 1;
222 }
223 if (!(match(&unquoted_val, &query_pattern,
224 (flags & MATCH_PREFIX) != 0,
225 (flags & MATCH_SUBSTRING) != 0)))
226 continue;
227 }
228 }
229 #endif /* WITHOUT_QUERY_FILTER */
230
231 if (!subsequent_resource) { /* this is the first resource */
232 subsequent_resource = 1;
233 } else {
234 PRINT_COND_WITH_OFFSET(p, bufend, offset, ',', written);
235 }
236
237 left = bufend - p; /* calculate available space */
238 result = coap_print_link(r, p, &left, &offset);
239
240 if (result & COAP_PRINT_STATUS_ERROR) {
241 break;
242 }
243
244 /* coap_print_link() returns the number of characters that
245 * where actually written to p. Now advance to its end. */
246 p += COAP_PRINT_OUTPUT_LENGTH(result);
247 written += left;
248 }
249
250 *buflen = written;
251 output_length = p - buf;
252
253 if (output_length > COAP_PRINT_STATUS_MAX) {
254 return COAP_PRINT_STATUS_ERROR;
255 }
256
257 result = (coap_print_status_t)output_length;
258
259 if (result + old_offset - offset < *buflen) {
260 result |= COAP_PRINT_STATUS_TRUNC;
261 }
262 return result;
263 }
264
265 static coap_str_const_t null_path_value = {0, (const uint8_t *)""};
266 static coap_str_const_t *null_path = &null_path_value;
267
268 coap_resource_t *
269 coap_resource_init(coap_str_const_t *uri_path, int flags) {
270 coap_resource_t *r;
271
272 r = (coap_resource_t *)coap_malloc_type(COAP_RESOURCE, sizeof(coap_resource_t));
273 if (r) {
274 memset(r, 0, sizeof(coap_resource_t));
275
276 if (!(flags & COAP_RESOURCE_FLAGS_RELEASE_URI)) {
277 /* Need to take a copy if caller is not providing a release request */
278 if (uri_path)
279 uri_path = coap_new_str_const(uri_path->s, uri_path->length);
280 else
281 uri_path = coap_new_str_const(null_path->s, null_path->length);
282 } else if (!uri_path) {
283 /* Do not expect this, but ... */
284 uri_path = coap_new_str_const(null_path->s, null_path->length);
285 }
286
287 if (uri_path)
288 r->uri_path = uri_path;
289
290 r->flags = flags;
291 r->observe = 2;
292 } else {
293 coap_log_debug("coap_resource_init: no memory left\n");
294 }
295
296 return r;
297 }
298
299 static const uint8_t coap_unknown_resource_uri[] =
300 "- Unknown -";
301
302 coap_resource_t *
303 coap_resource_unknown_init2(coap_method_handler_t put_handler, int flags) {
304 coap_resource_t *r;
305
306 r = (coap_resource_t *)coap_malloc_type(COAP_RESOURCE, sizeof(coap_resource_t));
307 if (r) {
308 memset(r, 0, sizeof(coap_resource_t));
309 r->is_unknown = 1;
310 /* Something unlikely to be used, but it shows up in the logs */
311 r->uri_path = coap_new_str_const(coap_unknown_resource_uri, sizeof(coap_unknown_resource_uri)-1);
312 r->flags = flags & COAP_RESOURCE_FLAGS_MCAST_LIST;
313 coap_register_handler(r, COAP_REQUEST_PUT, put_handler);
314 } else {
315 coap_log_debug("coap_resource_unknown_init: no memory left\n");
316 }
317
318 return r;
319 }
320
321 coap_resource_t *
322 coap_resource_unknown_init(coap_method_handler_t put_handler) {
323 return coap_resource_unknown_init2(put_handler, 0);
324 }
325
326 static const uint8_t coap_proxy_resource_uri[] =
327 "- Proxy URI -";
328
329 coap_resource_t *
330 coap_resource_proxy_uri_init2(coap_method_handler_t handler,
331 size_t host_name_count,
332 const char *host_name_list[], int flags) {
333 coap_resource_t *r;
334
335 if (host_name_count == 0) {
336 coap_log_err("coap_resource_proxy_uri_init: Must have one or more host names defined\n");
337 return NULL;
338 }
339 r = (coap_resource_t *)coap_malloc_type(COAP_RESOURCE, sizeof(coap_resource_t));
340 if (r) {
341 size_t i;
342 memset(r, 0, sizeof(coap_resource_t));
343 r->is_proxy_uri = 1;
344 /* Something unlikely to be used, but it shows up in the logs */
345 r->uri_path = coap_new_str_const(coap_proxy_resource_uri, sizeof(coap_proxy_resource_uri)-1);
346 /* Preset all the handlers */
347 for (i = 0; i < (sizeof(r->handler) / sizeof(r->handler[0])); i++) {
348 r->handler[i] = handler;
349 }
350 if (host_name_count) {
351 r->proxy_name_list = coap_malloc_type(COAP_STRING, host_name_count *
352 sizeof(coap_str_const_t *));
353 if (r->proxy_name_list) {
354 for (i = 0; i < host_name_count; i++) {
355 r->proxy_name_list[i] =
356 coap_new_str_const((const uint8_t *)host_name_list[i],
357 strlen(host_name_list[i]));
358 if (!r->proxy_name_list[i]) {
359 coap_log_err("coap_resource_proxy_uri_init: unable to add host name\n");
360 if (i == 0) {
361 coap_free_type(COAP_STRING, r->proxy_name_list);
362 r->proxy_name_list = NULL;
363 }
364 break;
365 }
366 }
367 r->proxy_name_count = i;
368 }
369 }
370 r->flags = flags & COAP_RESOURCE_FLAGS_MCAST_LIST;
371 } else {
372 coap_log_debug("coap_resource_proxy_uri_init2: no memory left\n");
373 }
374
375 return r;
376 }
377
378 coap_resource_t *
379 coap_resource_proxy_uri_init(coap_method_handler_t handler,
380 size_t host_name_count, const char *host_name_list[]) {
381 return coap_resource_proxy_uri_init2(handler, host_name_count,
382 host_name_list, 0);
383 }
384
385 coap_attr_t *
386 coap_add_attr(coap_resource_t *resource,
387 coap_str_const_t *name,
388 coap_str_const_t *val,
389 int flags) {
390 coap_attr_t *attr;
391
392 if (!resource || !name)
393 return NULL;
394 attr = (coap_attr_t *)coap_malloc_type(COAP_RESOURCEATTR, sizeof(coap_attr_t));
395
396 if (attr) {
397 if (!(flags & COAP_ATTR_FLAGS_RELEASE_NAME)) {
398 /* Need to take a copy if caller is not providing a release request */
399 name = coap_new_str_const(name->s, name->length);
400 }
401 attr->name = name;
402 if (val) {
403 if (!(flags & COAP_ATTR_FLAGS_RELEASE_VALUE)) {
404 /* Need to take a copy if caller is not providing a release request */
405 val = coap_new_str_const(val->s, val->length);
406 }
407 }
408 attr->value = val;
409
410 attr->flags = flags;
411
412 /* add attribute to resource list */
413 LL_PREPEND(resource->link_attr, attr);
414 } else {
415 coap_log_debug("coap_add_attr: no memory left\n");
416 }
417
418 return attr;
419 }
420
421 coap_attr_t *
422 coap_find_attr(coap_resource_t *resource,
423 coap_str_const_t *name) {
424 coap_attr_t *attr;
425
426 if (!resource || !name)
427 return NULL;
428
429 LL_FOREACH(resource->link_attr, attr) {
430 if (attr->name->length == name->length &&
431 memcmp(attr->name->s, name->s, name->length) == 0)
432 return attr;
433 }
434
435 return NULL;
436 }
437
438 coap_str_const_t *
439 coap_attr_get_value(coap_attr_t *attr) {
440 if (attr)
441 return attr->value;
442 return NULL;
443 }
444
445 void
446 coap_delete_attr(coap_attr_t *attr) {
447 if (!attr)
448 return;
449 coap_delete_str_const(attr->name);
450 if (attr->value) {
451 coap_delete_str_const(attr->value);
452 }
453
454 coap_free_type(COAP_RESOURCEATTR, attr);
455 }
456
457 typedef enum coap_deleting_resource_t {
458 COAP_DELETING_RESOURCE,
459 COAP_NOT_DELETING_RESOURCE
460 } coap_deleting_resource_t;
461
462 static void coap_notify_observers(coap_context_t *context, coap_resource_t *r,
463 coap_deleting_resource_t deleting);
464
465 static void
466 coap_free_resource(coap_resource_t *resource) {
467 coap_attr_t *attr, *tmp;
468 coap_subscription_t *obs, *otmp;
469
470 assert(resource);
471
472 if (!resource->context->observe_no_clear) {
473 coap_resource_notify_observers(resource, NULL);
474 coap_notify_observers(resource->context, resource, COAP_DELETING_RESOURCE);
475 }
476
477 if (resource->context->resource_deleted)
478 resource->context->resource_deleted(resource->context, resource->uri_path,
479 resource->context->observe_user_data);
480
481 if (resource->context->release_userdata && resource->user_data)
482 resource->context->release_userdata(resource->user_data);
483
484 /* delete registered attributes */
485 LL_FOREACH_SAFE(resource->link_attr, attr, tmp) coap_delete_attr(attr);
486
487 /* Either the application provided or libcoap copied - need to delete it */
488 coap_delete_str_const(resource->uri_path);
489
490 /* free all elements from resource->subscribers */
491 LL_FOREACH_SAFE(resource->subscribers, obs, otmp) {
492 if (resource->context->observe_deleted)
493 resource->context->observe_deleted(obs->session, obs,
494 resource->context->observe_user_data);
495 coap_session_release(obs->session);
496 coap_delete_pdu(obs->pdu);
497 coap_delete_cache_key(obs->cache_key);
498 coap_free_type(COAP_SUBSCRIPTION, obs);
499 }
500 if (resource->proxy_name_count && resource->proxy_name_list) {
501 size_t i;
502
503 for (i = 0; i < resource->proxy_name_count; i++) {
504 coap_delete_str_const(resource->proxy_name_list[i]);
505 }
506 coap_free_type(COAP_STRING, resource->proxy_name_list);
507 }
508
509 coap_free_type(COAP_RESOURCE, resource);
510 }
511
512 void
513 coap_add_resource(coap_context_t *context, coap_resource_t *resource) {
514 if (resource->is_unknown) {
515 if (context->unknown_resource)
516 coap_free_resource(context->unknown_resource);
517 context->unknown_resource = resource;
518 } else if (resource->is_proxy_uri) {
519 if (context->proxy_uri_resource)
520 coap_free_resource(context->proxy_uri_resource);
521 context->proxy_uri_resource = resource;
522 } else {
523 coap_resource_t *r = coap_get_resource_from_uri_path(context,
524 resource->uri_path);
525
526 if (r) {
527 coap_log_warn("coap_add_resource: Duplicate uri_path '%*.*s', old resource deleted\n",
528 (int)resource->uri_path->length, (int)resource->uri_path->length,
529 resource->uri_path->s);
530 coap_delete_resource(context, r);
531 }
532 RESOURCES_ADD(context->resources, resource);
533 #if COAP_WITH_OBSERVE_PERSIST
534 if (context->unknown_pdu && context->dyn_resource_save_file &&
535 context->dyn_resource_added && resource->observable) {
536 coap_bin_const_t raw_packet;
537
538 raw_packet.s = context->unknown_pdu->token -
539 context->unknown_pdu->hdr_size;
540 raw_packet.length = context->unknown_pdu->used_size +
541 context->unknown_pdu->hdr_size;
542 context->dyn_resource_added(context->unknown_session, resource->uri_path,
543 &raw_packet, context->observe_user_data);
544 }
545 #endif /* COAP_WITH_OBSERVE_PERSIST */
546 }
547 assert(resource->context == NULL);
548 resource->context = context;
549 }
550
551 /*
552 * Input context is ignored, but param left there to keep API consistent
553 */
554 int
555 coap_delete_resource(coap_context_t *context, coap_resource_t *resource) {
556 if (!resource)
557 return 0;
558
559 context = resource->context;
560
561 if (resource->is_unknown) {
562 if (context && context->unknown_resource == resource) {
563 context->unknown_resource = NULL;
564 }
565 } else if (resource->is_proxy_uri) {
566 if (context && context->proxy_uri_resource == resource) {
567 context->proxy_uri_resource = NULL;
568 }
569 } else if (context) {
570 /* remove resource from list */
571 RESOURCES_DELETE(context->resources, resource);
572 }
573
574 /* and free its allocated memory */
575 coap_free_resource(resource);
576
577 return 1;
578 }
579
580 void
581 coap_delete_all_resources(coap_context_t *context) {
582 coap_resource_t *res;
583 coap_resource_t *rtmp;
584
585 /* Cannot call RESOURCES_ITER because coap_free_resource() releases
586 * the allocated storage. */
587
588 HASH_ITER(hh, context->resources, res, rtmp) {
589 HASH_DELETE(hh, context->resources, res);
590 coap_free_resource(res);
591 }
592
593 context->resources = NULL;
594
595 if (context->unknown_resource) {
596 coap_free_resource(context->unknown_resource);
597 context->unknown_resource = NULL;
598 }
599 if (context->proxy_uri_resource) {
600 coap_free_resource(context->proxy_uri_resource);
601 context->proxy_uri_resource = NULL;
602 }
603 }
604
605 coap_resource_t *
606 coap_get_resource_from_uri_path(coap_context_t *context, coap_str_const_t *uri_path) {
607 coap_resource_t *result;
608
609 RESOURCES_FIND(context->resources, uri_path, result);
610
611 return result;
612 }
613
614 coap_print_status_t
615 coap_print_link(const coap_resource_t *resource,
616 unsigned char *buf, size_t *len, size_t *offset) {
617 unsigned char *p = buf;
618 const uint8_t *bufend = buf + *len;
619 coap_attr_t *attr;
620 coap_print_status_t result = 0;
621 size_t output_length = 0;
622 const size_t old_offset = *offset;
623
624 *len = 0;
625 PRINT_COND_WITH_OFFSET(p, bufend, *offset, '<', *len);
626 PRINT_COND_WITH_OFFSET(p, bufend, *offset, '/', *len);
627
628 COPY_COND_WITH_OFFSET(p, bufend, *offset,
629 resource->uri_path->s, resource->uri_path->length, *len);
630
631 PRINT_COND_WITH_OFFSET(p, bufend, *offset, '>', *len);
632
633 LL_FOREACH(resource->link_attr, attr) {
634
635 PRINT_COND_WITH_OFFSET(p, bufend, *offset, ';', *len);
636
637 COPY_COND_WITH_OFFSET(p, bufend, *offset,
638 attr->name->s, attr->name->length, *len);
639
640 if (attr->value && attr->value->s) {
641 PRINT_COND_WITH_OFFSET(p, bufend, *offset, '=', *len);
642
643 COPY_COND_WITH_OFFSET(p, bufend, *offset,
644 attr->value->s, attr->value->length, *len);
645 }
646
647 }
648 if (resource->observable) {
649 COPY_COND_WITH_OFFSET(p, bufend, *offset, ";obs", 4, *len);
650 }
651
652 #if COAP_OSCORE_SUPPORT
653 /* If oscore is enabled */
654 if (resource->flags & COAP_RESOURCE_FLAGS_OSCORE_ONLY)
655 COPY_COND_WITH_OFFSET(p, bufend, *offset, ";osc", 4, *len);
656 #endif /* COAP_OSCORE_SUPPORT */
657
658 output_length = p - buf;
659
660 if (output_length > COAP_PRINT_STATUS_MAX) {
661 return COAP_PRINT_STATUS_ERROR;
662 }
663
664 result = (coap_print_status_t)output_length;
665
666 if (result + old_offset - *offset < *len) {
667 result |= COAP_PRINT_STATUS_TRUNC;
668 }
669
670 return result;
671 }
672
673 void
674 coap_register_handler(coap_resource_t *resource,
675 coap_request_t method,
676 coap_method_handler_t handler) {
677 coap_register_request_handler(resource, method, handler);
678 }
679
680 void
681 coap_register_request_handler(coap_resource_t *resource,
682 coap_request_t method,
683 coap_method_handler_t handler) {
684 assert(resource);
685 assert(method > 0 && (size_t)(method-1) <
686 sizeof(resource->handler)/sizeof(coap_method_handler_t));
687 resource->handler[method-1] = handler;
688 }
689
690 coap_subscription_t *
691 coap_find_observer(coap_resource_t *resource, coap_session_t *session,
692 const coap_bin_const_t *token) {
693 coap_subscription_t *s;
694
695 assert(resource);
696 assert(session);
697
698 LL_FOREACH(resource->subscribers, s) {
699 if (s->session == session &&
700 (!token || coap_binary_equal(token, &s->pdu->actual_token)))
701 return s;
702 }
703
704 return NULL;
705 }
706
707 static coap_subscription_t *
708 coap_find_observer_cache_key(coap_resource_t *resource, coap_session_t *session,
709 const coap_cache_key_t *cache_key) {
710 coap_subscription_t *s;
711
712 assert(resource);
713 assert(session);
714
715 LL_FOREACH(resource->subscribers, s) {
716 if (s->session == session
717 && (memcmp(cache_key, s->cache_key, sizeof(coap_cache_key_t)) == 0))
718 return s;
719 }
720
721 return NULL;
722 }
723
724 coap_subscription_t *
725 coap_add_observer(coap_resource_t *resource,
726 coap_session_t *session,
727 const coap_bin_const_t *token,
728 const coap_pdu_t *request) {
729 coap_subscription_t *s;
730 coap_cache_key_t *cache_key = NULL;
731 size_t len;
732 const uint8_t *data;
733 /* https://rfc-editor.org/rfc/rfc7641#section-3.6 */
734 static const uint16_t cache_ignore_options[] = { COAP_OPTION_ETAG,
735 COAP_OPTION_OSCORE
736 };
737
738 assert(session);
739
740 /* Check if there is already a subscription for this peer. */
741 s = coap_find_observer(resource, session, token);
742 if (!s) {
743 /*
744 * Cannot allow a duplicate to be created for the same query as application
745 * may not be cleaning up duplicates. If duplicate found, then original
746 * observer is deleted and a new one created with the new token
747 */
748 cache_key = coap_cache_derive_key_w_ignore(session, request,
749 COAP_CACHE_IS_SESSION_BASED,
750 cache_ignore_options,
751 sizeof(cache_ignore_options)/sizeof(cache_ignore_options[0]));
752 if (cache_key) {
753 s = coap_find_observer_cache_key(resource, session, cache_key);
754 if (s) {
755 /* Delete old entry with old token */
756 coap_delete_observer(resource, session, &s->pdu->actual_token);
757 s = NULL;
758 }
759 }
760 }
761
762 /* We are done if subscription was found. */
763 if (s) {
764 return s;
765 }
766
767 /* Check if there is already maximum number of subscribers present */
768 #if (COAP_RESOURCE_MAX_SUBSCRIBER > 0)
769 uint32_t subscriber_count = 0;
770 LL_COUNT(resource->subscribers, s, subscriber_count);
771 if (subscriber_count >= COAP_RESOURCE_MAX_SUBSCRIBER) {
772 return NULL; /* Signal error */
773 }
774 #endif /* COAP_RESOURCE_MAX_SUBSCRIBER */
775
776 /* Create a new subscription */
777 s = coap_malloc_type(COAP_SUBSCRIPTION, sizeof(coap_subscription_t));
778
779 if (!s) {
780 coap_delete_cache_key(cache_key);
781 return NULL;
782 }
783
784 coap_subscription_init(s);
785 s->pdu = coap_pdu_duplicate(request, session, token->length,
786 token->s, NULL);
787 if (s->pdu == NULL) {
788 coap_delete_cache_key(cache_key);
789 coap_free_type(COAP_SUBSCRIPTION, s);
790 return NULL;
791 }
792 if (coap_get_data(request, &len, &data)) {
793 /* This could be a large bodied FETCH */
794 s->pdu->max_size = 0;
795 coap_add_data(s->pdu, len, data);
796 }
797 if (cache_key == NULL) {
798 cache_key = coap_cache_derive_key_w_ignore(session, request,
799 COAP_CACHE_IS_SESSION_BASED,
800 cache_ignore_options,
801 sizeof(cache_ignore_options)/sizeof(cache_ignore_options[0]));
802 if (cache_key == NULL) {
803 coap_delete_pdu(s->pdu);
804 coap_delete_cache_key(cache_key);
805 coap_free_type(COAP_SUBSCRIPTION, s);
806 return NULL;
807 }
808 }
809 s->cache_key = cache_key;
810 s->session = coap_session_reference(session);
811
812 /* add subscriber to resource */
813 LL_PREPEND(resource->subscribers, s);
814
815 coap_log_debug("create new subscription %p key 0x%02x%02x%02x%02x\n",
816 (void *)s, s->cache_key->key[0], s->cache_key->key[1],
817 s->cache_key->key[2], s->cache_key->key[3]);
818
819 if (session->context->observe_added && session->proto == COAP_PROTO_UDP) {
820 coap_bin_const_t raw_packet;
821 coap_bin_const_t *oscore_info = NULL;
822 #if COAP_OSCORE_SUPPORT
823 oscore_association_t *association;
824
825 if (session->recipient_ctx && session->recipient_ctx->recipient_id) {
826 /*
827 * Need to track the association used for tracking this observe, done as
828 * a CBOR array. Read in coap_persist_observe_add().
829 *
830 * If an entry is null, then use nil, else a set of bytes
831 *
832 * Currently tracking 5 items
833 * recipient_id
834 * id_context
835 * aad (from oscore_association_t)
836 * partial_iv (from oscore_association_t)
837 * nonce (from oscore_association_t)
838 */
839 uint8_t info_buffer[60];
840 uint8_t *info_buf = info_buffer;
841 size_t info_len = sizeof(info_buffer);
842 size_t ret = 0;
843 coap_bin_const_t ctoken = { token->length, token->s };
844
845 ret += oscore_cbor_put_array(&info_buf, &info_len, 5);
846 ret += oscore_cbor_put_bytes(&info_buf,
847 &info_len,
848 session->recipient_ctx->recipient_id->s,
849 session->recipient_ctx->recipient_id->length);
850 if (session->recipient_ctx->osc_ctx &&
851 session->recipient_ctx->osc_ctx->id_context) {
852 ret += oscore_cbor_put_bytes(&info_buf,
853 &info_len,
854 session->recipient_ctx->osc_ctx->id_context->s,
855 session->recipient_ctx->osc_ctx->id_context->length);
856 } else {
857 ret += oscore_cbor_put_nil(&info_buf, &info_len);
858 }
859 association = oscore_find_association(session, &ctoken);
860 if (association) {
861 if (association->aad) {
862 ret += oscore_cbor_put_bytes(&info_buf,
863 &info_len,
864 association->aad->s,
865 association->aad->length);
866 } else {
867 ret += oscore_cbor_put_nil(&info_buf, &info_len);
868 }
869 if (association->partial_iv) {
870 ret += oscore_cbor_put_bytes(&info_buf,
871 &info_len,
872 association->partial_iv->s,
873 association->partial_iv->length);
874 } else {
875 ret += oscore_cbor_put_nil(&info_buf, &info_len);
876 }
877 if (association->nonce) {
878 ret += oscore_cbor_put_bytes(&info_buf,
879 &info_len,
880 association->nonce->s,
881 association->nonce->length);
882 } else {
883 ret += oscore_cbor_put_nil(&info_buf, &info_len);
884 }
885 } else {
886 ret += oscore_cbor_put_nil(&info_buf, &info_len);
887 ret += oscore_cbor_put_nil(&info_buf, &info_len);
888 }
889 oscore_info = coap_new_bin_const(info_buffer, ret);
890 }
891 #endif /* COAP_OSCORE_SUPPORT */
892
893 /* s->pdu header is not currently encoded */
894 memcpy(s->pdu->token - request->hdr_size,
895 request->token - request->hdr_size, request->hdr_size);
896 raw_packet.s = s->pdu->token - request->hdr_size;
897 raw_packet.length = s->pdu->used_size + request->hdr_size;
898 session->context->observe_added(session, s, session->proto,
899 &session->endpoint->bind_addr,
900 &session->addr_info,
901 &raw_packet,
902 oscore_info,
903 session->context->observe_user_data);
904 #if COAP_OSCORE_SUPPORT
905 coap_delete_bin_const(oscore_info);
906 #endif /* COAP_OSCORE_SUPPORT */
907 }
908 if (resource->context->track_observe_value) {
909 /* Track last used observe value (as app handler is called) */
910 resource->context->track_observe_value(resource->context,resource->uri_path,
911 resource->observe,
912 resource->context->observe_user_data);
913 }
914
915 return s;
916 }
917
918 void
919 coap_touch_observer(coap_context_t *context, coap_session_t *session,
920 const coap_bin_const_t *token) {
921 coap_subscription_t *s;
922
923 RESOURCES_ITER(context->resources, r) {
924 s = coap_find_observer(r, session, token);
925 if (s) {
926 s->fail_cnt = 0;
927 }
928 }
929 }
930
931 int
932 coap_delete_observer(coap_resource_t *resource, coap_session_t *session,
933 const coap_bin_const_t *token) {
934 coap_subscription_t *s;
935
936 s = coap_find_observer(resource, session, token);
937
938 if (s && coap_get_log_level() >= COAP_LOG_DEBUG) {
939 char outbuf[2 * 8 + 1] = "";
940 unsigned int i;
941
942 for (i = 0; i < s->pdu->actual_token.length; i++) {
943 size_t size = strlen(outbuf);
944
945 snprintf(&outbuf[size], sizeof(outbuf)-size, "%02x",
946 s->pdu->actual_token.s[i]);
947 }
948 coap_log_debug("removed subscription %p with token '%s' key 0x%02x%02x%02x%02x\n",
949 (void *)s, outbuf, s->cache_key->key[0], s->cache_key->key[1],
950 s->cache_key->key[2], s-> cache_key->key[3]);
951 }
952 if (s && session->context->observe_deleted)
953 session->context->observe_deleted(session, s,
954 session->context->observe_user_data);
955
956 if (resource->subscribers && s) {
957 LL_DELETE(resource->subscribers, s);
958 coap_session_release(session);
959 coap_delete_pdu(s->pdu);
960 coap_delete_cache_key(s->cache_key);
961 coap_free_type(COAP_SUBSCRIPTION, s);
962 }
963
964 return s != NULL;
965 }
966
967 void
968 coap_delete_observers(coap_context_t *context, coap_session_t *session) {
969 RESOURCES_ITER(context->resources, resource) {
970 coap_subscription_t *s, *tmp;
971 LL_FOREACH_SAFE(resource->subscribers, s, tmp) {
972 if (s->session == session) {
973 if (context->observe_deleted)
974 context->observe_deleted(session, s, context->observe_user_data);
975 LL_DELETE(resource->subscribers, s);
976 coap_session_release(session);
977 coap_delete_pdu(s->pdu);
978 coap_delete_cache_key(s->cache_key);
979 coap_free_type(COAP_SUBSCRIPTION, s);
980 }
981 }
982 }
983 }
984
985 static void
986 coap_notify_observers(coap_context_t *context, coap_resource_t *r,
987 coap_deleting_resource_t deleting) {
988 coap_method_handler_t h;
989 coap_subscription_t *obs, *otmp;
990 coap_pdu_t *response;
991 uint8_t buf[4];
992 coap_string_t *query;
993 coap_block_b_t block;
994 coap_tick_t now;
995 coap_session_t *obs_session;
996
997 if (r->observable && (r->dirty || r->partiallydirty)) {
998 r->partiallydirty = 0;
999
1000 LL_FOREACH_SAFE(r->subscribers, obs, otmp) {
1001 obs_session = obs->session;
1002 if (r->dirty == 0 && obs->dirty == 0) {
1003 /*
1004 * running this resource due to partiallydirty, but this observation's
1005 * notification was already enqueued
1006 */
1007 context->observe_pending = 1;
1008 continue;
1009 }
1010 if (obs->session->con_active >= COAP_NSTART(obs->session) &&
1011 ((r->flags & COAP_RESOURCE_FLAGS_NOTIFY_CON) ||
1012 (obs->non_cnt >= COAP_OBS_MAX_NON))) {
1013 /* Waiting for the previous unsolicited response to finish */
1014 r->partiallydirty = 1;
1015 obs->dirty = 1;
1016 context->observe_pending = 1;
1017 continue;
1018 }
1019 coap_ticks(&now);
1020 if (obs->session->lg_xmit && obs->session->lg_xmit->last_all_sent == 0 &&
1021 obs->session->lg_xmit->last_obs &&
1022 (obs->session->lg_xmit->last_obs + 2*COAP_TICKS_PER_SECOND) > now) {
1023 /* Waiting for the previous blocked unsolicited response to finish */
1024 r->partiallydirty = 1;
1025 obs->dirty = 1;
1026 context->observe_pending = 1;
1027 continue;
1028 }
1029
1030 coap_mid_t mid = COAP_INVALID_MID;
1031 obs->dirty = 0;
1032 /* initialize response */
1033 response = coap_pdu_init(COAP_MESSAGE_CON, 0, 0, coap_session_max_pdu_size(obs->session));
1034 if (!response) {
1035 obs->dirty = 1;
1036 r->partiallydirty = 1;
1037 context->observe_pending = 1;
1038 coap_log_debug("coap_check_notify: pdu init failed, resource stays "
1039 "partially dirty\n");
1040 continue;
1041 }
1042
1043 if (!coap_add_token(response, obs->pdu->actual_token.length,
1044 obs->pdu->actual_token.s)) {
1045 obs->dirty = 1;
1046 r->partiallydirty = 1;
1047 context->observe_pending = 1;
1048 coap_log_debug("coap_check_notify: cannot add token, resource stays "
1049 "partially dirty\n");
1050 coap_delete_pdu(response);
1051 continue;
1052 }
1053
1054 obs->pdu->mid = response->mid = coap_new_message_id(obs->session);
1055 /* A lot of the reliable code assumes type is CON */
1056 if (COAP_PROTO_NOT_RELIABLE(obs->session->proto) &&
1057 (r->flags & COAP_RESOURCE_FLAGS_NOTIFY_CON) == 0 &&
1058 ((r->flags & COAP_RESOURCE_FLAGS_NOTIFY_NON_ALWAYS) ||
1059 obs->non_cnt < COAP_OBS_MAX_NON)) {
1060 response->type = COAP_MESSAGE_NON;
1061 } else {
1062 response->type = COAP_MESSAGE_CON;
1063 }
1064 switch (deleting) {
1065 case COAP_NOT_DELETING_RESOURCE:
1066 /* fill with observer-specific data */
1067 coap_add_option_internal(response, COAP_OPTION_OBSERVE,
1068 coap_encode_var_safe(buf, sizeof(buf),
1069 r->observe),
1070 buf);
1071 if (coap_get_block_b(obs->session, obs->pdu, COAP_OPTION_BLOCK2,
1072 &block)) {
1073 /* Will get updated later (e.g. M bit) if appropriate */
1074 coap_add_option_internal(response, COAP_OPTION_BLOCK2,
1075 coap_encode_var_safe(buf, sizeof(buf),
1076 ((0 << 4) |
1077 (0 << 3) |
1078 block.aszx)),
1079 buf);
1080 }
1081 #if COAP_Q_BLOCK_SUPPORT
1082 else if (coap_get_block_b(obs->session, obs->pdu, COAP_OPTION_Q_BLOCK2,
1083 &block)) {
1084 /* Will get updated later (e.g. M bit) if appropriate */
1085 coap_add_option_internal(response, COAP_OPTION_Q_BLOCK2,
1086 coap_encode_var_safe(buf, sizeof(buf),
1087 ((0 << 4) |
1088 (0 << 3) |
1089 block.szx)),
1090 buf);
1091 }
1092 #endif /* COAP_Q_BLOCK_SUPPORT */
1093
1094 h = r->handler[obs->pdu->code - 1];
1095 assert(h); /* we do not allow subscriptions if no
1096 * GET/FETCH handler is defined */
1097 query = coap_get_query(obs->pdu);
1098 coap_log_debug("Observe PDU presented to app.\n");
1099 coap_show_pdu(COAP_LOG_DEBUG, obs->pdu);
1100 coap_log_debug("call custom handler for resource '%*.*s' (4)\n",
1101 (int)r->uri_path->length, (int)r->uri_path->length,
1102 r->uri_path->s);
1103 h(r, obs->session, obs->pdu, query, response);
1104 /* Check if lg_xmit generated and update PDU code if so */
1105 coap_check_code_lg_xmit(obs->session, obs->pdu, response, r, query);
1106 coap_delete_string(query);
1107 if (COAP_RESPONSE_CLASS(response->code) != 2) {
1108 coap_remove_option(response, COAP_OPTION_OBSERVE);
1109 }
1110 if (COAP_RESPONSE_CLASS(response->code) > 2) {
1111 coap_delete_observer(r, obs->session, &obs->pdu->actual_token);
1112 obs = NULL;
1113 }
1114 break;
1115 case COAP_DELETING_RESOURCE:
1116 default:
1117 /* Don't worry if it does not get there */
1118 response->type = COAP_MESSAGE_NON;
1119 response->code = COAP_RESPONSE_CODE(404);
1120 break;
1121 }
1122
1123 if (obs) {
1124 if (response->type == COAP_MESSAGE_CON ||
1125 (r->flags & COAP_RESOURCE_FLAGS_NOTIFY_NON_ALWAYS)) {
1126 obs->non_cnt = 0;
1127 } else {
1128 obs->non_cnt++;
1129 }
1130
1131 #if COAP_Q_BLOCK_SUPPORT
1132 if (response->code == COAP_RESPONSE_CODE(205) &&
1133 coap_get_block_b(obs->session, response, COAP_OPTION_Q_BLOCK2,
1134 &block) &&
1135 block.m) {
1136 query = coap_get_query(obs->pdu);
1137 mid = coap_send_q_block2(obs->session, r, query, obs->pdu->code,
1138 block, response, 1);
1139 coap_delete_string(query);
1140 goto finish;
1141 }
1142 #endif /* COAP_Q_BLOCK_SUPPORT */
1143 }
1144 mid = coap_send_internal(obs_session, response);
1145
1146 #if COAP_Q_BLOCK_SUPPORT
1147 finish:
1148 #endif /* COAP_Q_BLOCK_SUPPORT */
1149 if (COAP_INVALID_MID == mid && obs) {
1150 coap_subscription_t *s;
1151 coap_log_debug("coap_check_notify: sending failed, resource stays "
1152 "partially dirty\n");
1153 LL_FOREACH(r->subscribers, s) {
1154 if (s == obs) {
1155 /* obs not deleted during coap_send_internal() */
1156 obs->dirty = 1;
1157 break;
1158 }
1159 }
1160 r->partiallydirty = 1;
1161 context->observe_pending = 1;
1162 }
1163 }
1164 }
1165 r->dirty = 0;
1166 }
1167
1168 int
1169 coap_resource_set_dirty(coap_resource_t *r, const coap_string_t *query) {
1170 return coap_resource_notify_observers(r, query);
1171 }
1172
1173 int
1174 coap_resource_notify_observers(coap_resource_t *r,
1175 const coap_string_t *query COAP_UNUSED) {
1176 if (!r->observable)
1177 return 0;
1178 if (!r->subscribers)
1179 return 0;
1180 r->dirty = 1;
1181
1182 /* Increment value for next Observe use. Observe value must be < 2^24 */
1183 r->observe = (r->observe + 1) & 0xFFFFFF;
1184
1185 assert(r->context);
1186
1187 if (r->context->track_observe_value) {
1188 /* Track last used observe value */
1189 if ((r->observe % r->context->observe_save_freq) == 0)
1190 r->context->track_observe_value(r->context, r->uri_path,
1191 r->observe,
1192 r->context->observe_user_data);
1193 }
1194
1195 r->context->observe_pending = 1;
1196 #ifdef COAP_EPOLL_SUPPORT
1197 coap_update_epoll_timer(r->context, 0);
1198 #endif /* COAP_EPOLL_SUPPORT */
1199 return 1;
1200 }
1201
1202 void
1203 coap_resource_set_mode(coap_resource_t *resource, int mode) {
1204 resource->flags = (resource->flags &
1205 ~(COAP_RESOURCE_FLAGS_NOTIFY_CON|COAP_RESOURCE_FLAGS_NOTIFY_NON)) |
1206 (mode & (COAP_RESOURCE_FLAGS_NOTIFY_CON|COAP_RESOURCE_FLAGS_NOTIFY_NON));
1207 }
1208
1209 void
1210 coap_resource_set_userdata(coap_resource_t *resource, void *data) {
1211 resource->user_data = data;
1212 }
1213
1214 void *
1215 coap_resource_get_userdata(coap_resource_t *resource) {
1216 return resource->user_data;
1217 }
1218
1219 void
1220 coap_resource_release_userdata_handler(coap_context_t *context,
1221 coap_resource_release_userdata_handler_t callback) {
1222 context->release_userdata = callback;
1223 }
1224
1225 void
1226 coap_resource_set_get_observable(coap_resource_t *resource, int mode) {
1227 resource->observable = mode ? 1 : 0;
1228 }
1229
1230 coap_str_const_t *
1231 coap_resource_get_uri_path(coap_resource_t *resource) {
1232 if (resource)
1233 return resource->uri_path;
1234 return NULL;
1235 }
1236
1237 void
1238 coap_check_notify(coap_context_t *context) {
1239
1240 if (context->observe_pending) {
1241 context->observe_pending = 0;
1242 RESOURCES_ITER(context->resources, r) {
1243 coap_notify_observers(context, r, COAP_NOT_DELETING_RESOURCE);
1244 }
1245 }
1246 }
1247
1248 void
1249 coap_persist_set_observe_num(coap_resource_t *resource,
1250 uint32_t start_observe_no) {
1251 if (!resource)
1252 return;
1253
1254 resource->observe = start_observe_no & 0xffffff;
1255 }
1256
1257 /**
1258 * Checks the failure counter for (peer, token) and removes peer from
1259 * the list of observers for the given resource when COAP_OBS_MAX_FAIL
1260 * is reached.
1261 *
1262 * @param context The CoAP context to use
1263 * @param resource The resource to check for (peer, token)
1264 * @param session The observer's session
1265 * @param token The token that has been used for subscription.
1266 */
1267 static void
1268 coap_remove_failed_observers(coap_context_t *context,
1269 coap_resource_t *resource,
1270 coap_session_t *session,
1271 const coap_bin_const_t *token) {
1272 coap_subscription_t *obs, *otmp;
1273
1274 LL_FOREACH_SAFE(resource->subscribers, obs, otmp) {
1275 if (obs->session == session &&
1276 coap_binary_equal(token, &obs->pdu->actual_token)) {
1277 /* count failed notifies and remove when
1278 * COAP_OBS_MAX_FAIL is reached */
1279 obs->fail_cnt++;
1280 if (obs->fail_cnt >= COAP_OBS_MAX_FAIL) {
1281 coap_cancel_all_messages(context, obs->session,
1282 &obs->pdu->actual_token);
1283 coap_delete_observer(resource, session, token);
1284 }
1285 break; /* break loop if observer was found */
1286 }
1287 }
1288 }
1289
1290 void
1291 coap_handle_failed_notify(coap_context_t *context,
1292 coap_session_t *session,
1293 const coap_bin_const_t *token) {
1294
1295 RESOURCES_ITER(context->resources, r) {
1296 coap_remove_failed_observers(context, r, session, token);
1297 }
1298 }
1299
1300 #endif /* ! COAP_SERVER_SUPPORT */
1301