1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
|
/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
#pragma once
/*****
***** Module Info
*****/
/*! \file dns/cache.h
* \brief
* Defines dns_cache_t, the cache object.
*
* Notes:
*\li A cache object contains DNS data of a single class.
* Multiple classes will be handled by creating multiple
* views, each with a different class and its own cache.
*
* MP:
*\li See notes at the individual functions.
*
* Reliability:
*
* Resources:
*
* Security:
*
* Standards:
*/
/***
*** Imports
***/
#include <stdbool.h>
#include <isc/lang.h>
#include <isc/stats.h>
#include <isc/stdtime.h>
#include <dns/types.h>
ISC_LANG_BEGINDECLS
/***
*** Functions
***/
isc_result_t
dns_cache_create(isc_mem_t *cmctx, isc_mem_t *hmctx, isc_taskmgr_t *taskmgr,
isc_timermgr_t *timermgr, dns_rdataclass_t rdclass,
const char *cachename, const char *db_type,
unsigned int db_argc, char **db_argv, dns_cache_t **cachep);
/*%<
* Create a new DNS cache.
*
* dns_cache_create2() will create a named cache.
*
* dns_cache_create3() will create a named cache using two separate memory
* contexts, one for cache data which can be cleaned and a separate one for
* memory allocated for the heap (which can grow without an upper limit and
* has no mechanism for shrinking).
*
* dns_cache_create() is a backward compatible version that internally
* specifies an empty cache name and a single memory context.
*
* Requires:
*
*\li 'cmctx' (and 'hmctx' if applicable) is a valid memory context.
*
*\li 'taskmgr' is a valid task manager and 'timermgr' is a valid timer
* manager, or both are NULL. If NULL, no periodic cleaning of the
* cache will take place.
*
*\li 'cachename' is a valid string. This must not be NULL.
*
*\li 'cachep' is a valid pointer, and *cachep == NULL
*
* Ensures:
*
*\li '*cachep' is attached to the newly created cache
*
* Returns:
*
*\li #ISC_R_SUCCESS
*\li #ISC_R_NOMEMORY
*/
void
dns_cache_attach(dns_cache_t *cache, dns_cache_t **targetp);
/*%<
* Attach *targetp to cache.
*
* Requires:
*
*\li 'cache' is a valid cache.
*
*\li 'targetp' points to a NULL dns_cache_t *.
*
* Ensures:
*
*\li *targetp is attached to cache.
*/
void
dns_cache_detach(dns_cache_t **cachep);
/*%<
* Detach *cachep from its cache.
*
* Requires:
*
*\li 'cachep' points to a valid cache.
*
* Ensures:
*
*\li *cachep is NULL.
*
*\li If '*cachep' is the last reference to the cache,
* all resources used by the cache will be freed
*/
void
dns_cache_attachdb(dns_cache_t *cache, dns_db_t **dbp);
/*%<
* Attach *dbp to the cache's database.
*
* Notes:
*
*\li This may be used to get a reference to the database for
* the purpose of cache lookups (XXX currently it is also
* the way to add data to the cache, but having a
* separate dns_cache_add() interface instead would allow
* more control over memory usage).
* The caller should call dns_db_detach() on the reference
* when it is no longer needed.
*
* Requires:
*
*\li 'cache' is a valid cache.
*
*\li 'dbp' points to a NULL dns_db *.
*
* Ensures:
*
*\li *dbp is attached to the database.
*/
isc_result_t
dns_cache_clean(dns_cache_t *cache, isc_stdtime_t now);
/*%<
* Force immediate cleaning of the cache, freeing all rdatasets
* whose TTL has expired as of 'now' and that have no pending
* references.
*/
const char *
dns_cache_getname(dns_cache_t *cache);
/*%<
* Get the cache name.
*/
void
dns_cache_setcachesize(dns_cache_t *cache, size_t size);
/*%<
* Set the maximum cache size. 0 means unlimited.
*/
size_t
dns_cache_getcachesize(dns_cache_t *cache);
/*%<
* Get the maximum cache size.
*/
void
dns_cache_setservestalettl(dns_cache_t *cache, dns_ttl_t ttl);
/*%<
* Sets the maximum length of time that cached answers may be retained
* past their normal TTL. Default value for the library is 0, disabling
* the use of stale data.
*
* Requires:
*\li 'cache' to be valid.
*/
dns_ttl_t
dns_cache_getservestalettl(dns_cache_t *cache);
/*%<
* Gets the maximum length of time that cached answers may be kept past
* normal expiry.
*
* Requires:
*\li 'cache' to be valid.
*/
void
dns_cache_setservestalerefresh(dns_cache_t *cache, dns_ttl_t interval);
/*%<
* Sets the length of time to wait before attempting to refresh a rrset
* if a previous attempt in doing so has failed.
* During this time window if stale rrset are available in cache they
* will be directly returned to client.
*
* Requires:
*\li 'cache' to be valid.
*/
dns_ttl_t
dns_cache_getservestalerefresh(dns_cache_t *cache);
/*%<
* Gets the 'stale-refresh-time' value, set by a previous call to
* 'dns_cache_setservestalerefresh'.
*
* Requires:
*\li 'cache' to be valid.
*/
isc_result_t
dns_cache_flush(dns_cache_t *cache);
/*%<
* Flushes all data from the cache.
*
* Returns:
*\li #ISC_R_SUCCESS
*\li #ISC_R_NOMEMORY
*/
isc_result_t
dns_cache_flushnode(dns_cache_t *cache, const dns_name_t *name, bool tree);
/*
* Flush a given name from the cache. If 'tree' is true, then
* also flush all names under 'name'.
*
* Requires:
*\li 'cache' to be valid.
*\li 'name' to be valid.
*
* Returns:
*\li #ISC_R_SUCCESS
*\li #ISC_R_NOMEMORY
*\li other error returns.
*/
isc_result_t
dns_cache_flushname(dns_cache_t *cache, const dns_name_t *name);
/*
* Flush a given name from the cache. Equivalent to
* dns_cache_flushpartial(cache, name, false).
*
* Requires:
*\li 'cache' to be valid.
*\li 'name' to be valid.
*
* Returns:
*\li #ISC_R_SUCCESS
*\li #ISC_R_NOMEMORY
*\li other error returns.
*/
isc_stats_t *
dns_cache_getstats(dns_cache_t *cache);
/*
* Return a pointer to the stats collection object for 'cache'
*/
void
dns_cache_dumpstats(dns_cache_t *cache, FILE *fp);
/*
* Dump cache statistics and status in text to 'fp'
*/
void
dns_cache_updatestats(dns_cache_t *cache, isc_result_t result);
/*
* Update cache statistics based on result code in 'result'
*/
#ifdef HAVE_LIBXML2
int
dns_cache_renderxml(dns_cache_t *cache, void *writer0);
/*
* Render cache statistics and status in XML for 'writer'.
*/
#endif /* HAVE_LIBXML2 */
#ifdef HAVE_JSON_C
isc_result_t
dns_cache_renderjson(dns_cache_t *cache, void *cstats0);
/*
* Render cache statistics and status in JSON
*/
#endif /* HAVE_JSON_C */
ISC_LANG_ENDDECLS
|
