libcoap 4.3.0
coap_cache.c
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1/* coap_cache.c -- Caching of CoAP requests
2*
3* Copyright (C) 2020 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#include "coap3/coap_internal.h"
12
13/* Determines if the given option_type denotes an option type that can
14 * be used as CacheKey. Options that can be cache keys are not Unsafe
15 * and not marked explicitly as NoCacheKey. */
16static int
17is_cache_key(uint16_t option_type, size_t cache_ignore_count,
18 const uint16_t *cache_ignore_options) {
19 size_t i;
20
21 /* https://tools.ietf.org/html/rfc7252#section-5.4.6 Nocachekey definition */
22 if ((option_type & 0x1e) == 0x1c)
23 return 0;
24 /*
25 * https://tools.ietf.org/html/rfc7641#section-2 Observe is not a
26 * part of the cache-key.
27 */
28 if (option_type == COAP_OPTION_OBSERVE)
29 return 0;
30
31 /* Check for option user has defined as not part of cache-key */
32 for (i = 0; i < cache_ignore_count; i++) {
33 if (cache_ignore_options[i] == option_type) {
34 return 0;
35 }
36 }
37
38 return 1;
39}
40
41int
43 const uint16_t *options,
44 size_t count) {
45 if (ctx->cache_ignore_options) {
47 }
48 if (count) {
49 assert(options);
50 ctx->cache_ignore_options = coap_malloc(count * sizeof(options[0]));
51 if (ctx->cache_ignore_options) {
52 memcpy(ctx->cache_ignore_options, options, count * sizeof(options[0]));
53 ctx->cache_ignore_count = count;
54 }
55 else {
56 coap_log(LOG_WARNING, "Unable to create cache_ignore_options\n");
57 return 0;
58 }
59 }
60 else {
61 ctx->cache_ignore_options = NULL;
62 ctx->cache_ignore_count = count;
63 }
64 return 1;
65}
66
69 const coap_pdu_t *pdu,
70 coap_cache_session_based_t session_based,
71 const uint16_t *cache_ignore_options,
72 size_t cache_ignore_count) {
73 coap_opt_t *option;
74 coap_opt_iterator_t opt_iter;
76 coap_digest_t digest;
77 coap_cache_key_t *cache_key;
78
79 if (!coap_option_iterator_init(pdu, &opt_iter, COAP_OPT_ALL)) {
80 return NULL;
81 }
82
83 dctx = coap_digest_setup();
84 if (!dctx)
85 return NULL;
86
87 if (session_based == COAP_CACHE_IS_SESSION_BASED) {
88 /* Include the session ptr */
89 if (!coap_digest_update(dctx, (const uint8_t*)session, sizeof(session))) {
90 coap_digest_free(dctx);
91 return NULL;
92 }
93 }
94 while ((option = coap_option_next(&opt_iter))) {
95 if (is_cache_key(opt_iter.number, cache_ignore_count,
96 cache_ignore_options)) {
97 if (!coap_digest_update(dctx, option, coap_opt_size(option))) {
98 coap_digest_free(dctx);
99 return NULL;
100 }
101 }
102 }
103
104 /* The body of a FETCH payload is part of the cache key,
105 * see https://tools.ietf.org/html/rfc8132#section-2 */
106 if (pdu->code == COAP_REQUEST_CODE_FETCH) {
107 size_t len;
108 const uint8_t *data;
109 if (coap_get_data(pdu, &len, &data)) {
110 if (!coap_digest_update(dctx, data, len)) {
111 coap_digest_free(dctx);
112 return NULL;
113 }
114 }
115 }
116
117 if (!coap_digest_final(dctx, &digest)) {
118 /* coap_digest_final() is guaranteed to free off dctx no matter what */
119 return NULL;
120 }
122 if (cache_key) {
123 memcpy(cache_key->key, digest.key, sizeof(cache_key->key));
124 }
125 return cache_key;
126}
127
130 const coap_pdu_t *pdu,
131 coap_cache_session_based_t session_based) {
132 return coap_cache_derive_key_w_ignore(session, pdu, session_based,
134 session->context->cache_ignore_count);
135}
136
137void
139 coap_free_type(COAP_CACHE_KEY, cache_key);
140}
141
144 coap_cache_record_pdu_t record_pdu,
145 coap_cache_session_based_t session_based,
146 unsigned int idle_timeout) {
148 sizeof(coap_cache_entry_t));
149 if (!entry) {
150 return NULL;
151 }
152
153 memset(entry, 0, sizeof(coap_cache_entry_t));
154 entry->session = session;
155 if (record_pdu == COAP_CACHE_RECORD_PDU) {
156 entry->pdu = coap_pdu_init(pdu->type, pdu->code, pdu->mid, pdu->alloc_size);
157 if (entry->pdu) {
158 if (!coap_pdu_resize(entry->pdu, pdu->alloc_size)) {
159 coap_delete_pdu(entry->pdu);
161 return NULL;
162 }
163 /* Need to get the appropriate data across */
164 memcpy(entry->pdu, pdu, offsetof(coap_pdu_t, token));
165 memcpy(entry->pdu->token, pdu->token, pdu->used_size);
166 /* And adjust all the pointers etc. */
167 entry->pdu->data = entry->pdu->token + (pdu->data - pdu->token);
168 }
169 }
170 entry->cache_key = coap_cache_derive_key(session, pdu, session_based);
171 if (!entry->cache_key) {
173 return NULL;
174 }
175 entry->idle_timeout = idle_timeout;
176 if (idle_timeout > 0) {
177 coap_ticks(&entry->expire_ticks);
178 entry->expire_ticks += idle_timeout * COAP_TICKS_PER_SECOND;
179 }
180
181 HASH_ADD(hh, session->context->cache, cache_key[0], sizeof(coap_cache_key_t), entry);
182 return entry;
183}
184
187 coap_cache_entry_t *cache_entry = NULL;
188
189 assert(cache_key);
190 if (cache_key) {
191 HASH_FIND(hh, ctx->cache, cache_key, sizeof(coap_cache_key_t), cache_entry);
192 }
193 if (cache_entry && cache_entry->idle_timeout > 0) {
194 coap_ticks(&cache_entry->expire_ticks);
195 cache_entry->expire_ticks += cache_entry->idle_timeout * COAP_TICKS_PER_SECOND;
196 }
197 return cache_entry;
198}
199
202 const coap_pdu_t *request,
203 coap_cache_session_based_t session_based) {
204 coap_cache_key_t *cache_key = coap_cache_derive_key(session, request, session_based);
205 coap_cache_entry_t *cache_entry;
206
207 if (!cache_key)
208 return NULL;
209
210 cache_entry = coap_cache_get_by_key(session->context, cache_key);
211 coap_delete_cache_key(cache_key);
212 if (cache_entry && cache_entry->idle_timeout > 0) {
213 coap_ticks(&cache_entry->expire_ticks);
214 cache_entry->expire_ticks += cache_entry->idle_timeout * COAP_TICKS_PER_SECOND;
215 }
216 return cache_entry;
217}
218
219void
221
222 assert(cache_entry);
223
224 if (cache_entry) {
225 HASH_DELETE(hh, ctx->cache, cache_entry);
226 }
227 if (cache_entry->pdu) {
228 coap_delete_pdu(cache_entry->pdu);
229 }
230 coap_delete_cache_key(cache_entry->cache_key);
231 if (cache_entry->callback && cache_entry->app_data) {
232 cache_entry->callback(cache_entry->app_data);
233 }
234 coap_free_type(COAP_CACHE_ENTRY, cache_entry);
235}
236
237const coap_pdu_t *
239 return cache_entry->pdu;
240}
241
242void
244 void *data,
246 cache_entry->app_data = data;
247 cache_entry->callback = callback;
248}
249
250void *
252 return cache_entry->app_data;
253}
254
255void
257 coap_tick_t now;
258 coap_cache_entry_t *cp, *ctmp;
259
260 coap_ticks(&now);
261 HASH_ITER(hh, ctx->cache, cp, ctmp) {
262 if (cp->idle_timeout > 0) {
263 if (cp->expire_ticks <= now) {
265 }
266 }
267 }
268}
269
static int is_cache_key(uint16_t option_type, size_t cache_ignore_count, const uint16_t *cache_ignore_options)
Definition: coap_cache.c:17
Pulls together all the internal only header files.
void coap_digest_free(coap_digest_ctx_t *digest_ctx)
Free off coap_digest_ctx_t.
Definition: coap_notls.c:205
int coap_digest_final(coap_digest_ctx_t *digest_ctx, coap_digest_t *digest_buffer)
Finalize the coap_digest information into the provided digest_buffer.
Definition: coap_notls.c:222
int coap_digest_update(coap_digest_ctx_t *digest_ctx, const uint8_t *data, size_t data_len)
Update the coap_digest information with the next chunk of data.
Definition: coap_notls.c:210
void coap_digest_ctx_t
void coap_expire_cache_entries(coap_context_t *ctx)
Expire coap_cache_entry_t entries.
Definition: coap_cache.c:256
coap_digest_ctx_t * coap_digest_setup(void)
Initialize a coap_digest.
Definition: coap_notls.c:194
void coap_delete_cache_entry(coap_context_t *ctx, coap_cache_entry_t *cache_entry)
Remove a cache-entry from the hash list and free off all the appropriate contents apart from app_data...
Definition: coap_cache.c:220
void coap_delete_cache_key(coap_cache_key_t *cache_key)
Delete the cache-key.
Definition: coap_cache.c:138
coap_cache_key_t * coap_cache_derive_key(const coap_session_t *session, const coap_pdu_t *pdu, coap_cache_session_based_t session_based)
Calculates a cache-key for the given CoAP PDU.
Definition: coap_cache.c:129
coap_cache_record_pdu_t
Definition: coap_cache.h:40
void(* coap_cache_app_data_free_callback_t)(void *data)
Callback to free off the app data when the cache-entry is being deleted / freed off.
Definition: coap_cache.h:33
const coap_pdu_t * coap_cache_get_pdu(const coap_cache_entry_t *cache_entry)
Returns the PDU information stored in the coap_cache entry.
Definition: coap_cache.c:238
coap_cache_entry_t * coap_cache_get_by_pdu(coap_session_t *session, const coap_pdu_t *request, coap_cache_session_based_t session_based)
Searches for a cache-entry corresponding to pdu.
Definition: coap_cache.c:201
int coap_cache_ignore_options(coap_context_t *ctx, const uint16_t *options, size_t count)
Define the CoAP options that are not to be included when calculating the cache-key.
Definition: coap_cache.c:42
coap_cache_key_t * coap_cache_derive_key_w_ignore(const coap_session_t *session, const coap_pdu_t *pdu, coap_cache_session_based_t session_based, const uint16_t *cache_ignore_options, size_t cache_ignore_count)
Calculates a cache-key for the given CoAP PDU.
Definition: coap_cache.c:68
coap_cache_entry_t * coap_new_cache_entry(coap_session_t *session, const coap_pdu_t *pdu, coap_cache_record_pdu_t record_pdu, coap_cache_session_based_t session_based, unsigned int idle_timeout)
Create a new cache-entry hash keyed by cache-key derived from the PDU.
Definition: coap_cache.c:143
void * coap_cache_get_app_data(const coap_cache_entry_t *cache_entry)
Returns any application-specific data that has been stored with cache_entry using the function coap_c...
Definition: coap_cache.c:251
coap_cache_entry_t * coap_cache_get_by_key(coap_context_t *ctx, const coap_cache_key_t *cache_key)
Searches for a cache-entry identified by cache_key.
Definition: coap_cache.c:186
void coap_cache_set_app_data(coap_cache_entry_t *cache_entry, void *data, coap_cache_app_data_free_callback_t callback)
Stores data with the given cache entry.
Definition: coap_cache.c:243
coap_cache_session_based_t
Definition: coap_cache.h:35
@ COAP_CACHE_RECORD_PDU
Definition: coap_cache.h:42
@ COAP_CACHE_IS_SESSION_BASED
Definition: coap_cache.h:37
void coap_ticks(coap_tick_t *t)
Sets t to the internal time with COAP_TICKS_PER_SECOND resolution.
uint64_t coap_tick_t
This data type represents internal timer ticks with COAP_TICKS_PER_SECOND resolution.
Definition: coap_time.h:122
#define COAP_TICKS_PER_SECOND
Use ms resolution on POSIX systems.
Definition: coap_time.h:137
#define coap_log(level,...)
Logging function.
Definition: coap_debug.h:152
@ LOG_WARNING
Warning.
Definition: coap_debug.h:56
coap_opt_t * coap_option_next(coap_opt_iterator_t *oi)
Updates the iterator oi to point to the next option.
Definition: option.c:148
coap_opt_iterator_t * coap_option_iterator_init(const coap_pdu_t *pdu, coap_opt_iterator_t *oi, const coap_opt_filter_t *filter)
Initializes the given option iterator oi to point to the beginning of the pdu's option list.
Definition: option.c:112
#define COAP_OPT_ALL
Pre-defined filter that includes all options.
Definition: option.h:107
int coap_pdu_resize(coap_pdu_t *pdu, size_t new_size)
Dynamically grows the size of pdu to new_size.
Definition: pdu.c:207
void coap_delete_pdu(coap_pdu_t *pdu)
Dispose of an CoAP PDU and frees associated storage.
Definition: pdu.c:142
int coap_get_data(const coap_pdu_t *pdu, size_t *len, const uint8_t **data)
Retrieves the length and data pointer of specified PDU.
Definition: pdu.c:654
coap_pdu_t * coap_pdu_init(coap_pdu_type_t type, coap_pdu_code_t code, coap_mid_t mid, size_t size)
Creates a new CoAP PDU with at least enough storage space for the given size maximum message size.
Definition: pdu.c:87
#define COAP_OPTION_OBSERVE
Definition: pdu.h:111
@ COAP_REQUEST_CODE_FETCH
Definition: pdu.h:298
COAP_STATIC_INLINE void coap_free(void *object)
Wrapper function to coap_free_type() for backwards compatibility.
Definition: mem.h:105
COAP_STATIC_INLINE void * coap_malloc(size_t size)
Wrapper function to coap_malloc_type() for backwards compatibility.
Definition: mem.h:98
@ COAP_CACHE_KEY
Definition: mem.h:48
@ COAP_CACHE_ENTRY
Definition: mem.h:49
void * coap_malloc_type(coap_memory_tag_t type, size_t size)
Allocates a chunk of size bytes and returns a pointer to the newly allocated memory.
void coap_free_type(coap_memory_tag_t type, void *p)
Releases the memory that was allocated by coap_malloc_type().
size_t coap_opt_size(const coap_opt_t *opt)
Returns the size of the given option, taking into account a possible option jump.
Definition: option.c:283
uint8_t coap_opt_t
Use byte-oriented access methods here because sliding a complex struct coap_opt_t over the data buffe...
Definition: option.h:26
coap_session_t * session
coap_cache_app_data_free_callback_t callback
coap_tick_t expire_ticks
void * app_data
unsigned int idle_timeout
coap_cache_key_t * cache_key
coap_pdu_t * pdu
The CoAP stack's global state is stored in a coap_context_t object.
uint16_t * cache_ignore_options
CoAP options to ignore when creating a cache-key.
size_t cache_ignore_count
The number of CoAP options to ignore when creating a cache-key.
coap_cache_entry_t * cache
CoAP cache-entry cache.
Iterator to run through PDU options.
Definition: option.h:170
coap_option_num_t number
decoded option number
Definition: option.h:172
structure for CoAP PDUs token, if any, follows the fixed size header, then options until payload mark...
uint8_t * token
first byte of token, if any, or options
coap_pdu_code_t code
request method (value 1–31) or response code (value 64-255)
uint8_t * data
first byte of payload, if any
coap_mid_t mid
message id, if any, in regular host byte order
size_t used_size
used bytes of storage for token, options and payload
size_t alloc_size
allocated storage for token, options and payload
coap_pdu_type_t type
message type
Abstraction of virtual session that can be attached to coap_context_t (client) or coap_endpoint_t (se...
coap_context_t * context
session's context