GNUnet  0.18.1
Data Cache library

Simple, transient hash table of bounded size with content expiration. More...

Collaboration diagram for Data Cache library:

Data Structures

struct  GNUNET_DATACACHE_Block
 Information about a block stored in the datacache. More...
 

Typedefs

typedef enum GNUNET_GenericReturnValue(* GNUNET_DATACACHE_Iterator) (void *cls, const struct GNUNET_DATACACHE_Block *block)
 An iterator over a set of items stored in the datacache. More...
 

Functions

struct GNUNET_DATACACHE_HandleGNUNET_DATACACHE_create (const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section)
 Create a data cache. More...
 
void GNUNET_DATACACHE_destroy (struct GNUNET_DATACACHE_Handle *h)
 Destroy a data cache (and free associated resources). More...
 
enum GNUNET_GenericReturnValue GNUNET_DATACACHE_put (struct GNUNET_DATACACHE_Handle *h, uint32_t xor_distance, const struct GNUNET_DATACACHE_Block *block)
 Store an item in the datacache. More...
 
unsigned int GNUNET_DATACACHE_get (struct GNUNET_DATACACHE_Handle *h, const struct GNUNET_HashCode *key, enum GNUNET_BLOCK_Type type, GNUNET_DATACACHE_Iterator iter, void *iter_cls)
 Iterate over the results for a particular key in the datacache. More...
 
unsigned int GNUNET_DATACACHE_get_closest (struct GNUNET_DATACACHE_Handle *h, const struct GNUNET_HashCode *key, enum GNUNET_BLOCK_Type type, unsigned int num_results, GNUNET_DATACACHE_Iterator iter, void *iter_cls)
 Iterate over the results that are "close" to a particular key in the datacache. More...
 

Detailed Description

Simple, transient hash table of bounded size with content expiration.

In contrast to the sqstore there is no prioritization, deletion or iteration. All of the data is discarded when the peer shuts down!

Typedef Documentation

◆ GNUNET_DATACACHE_Iterator

typedef enum GNUNET_GenericReturnValue(* GNUNET_DATACACHE_Iterator) (void *cls, const struct GNUNET_DATACACHE_Block *block)

An iterator over a set of items stored in the datacache.

Parameters
clsclosure
blocka block from the datacache
Returns
GNUNET_OK to continue iterating, GNUNET_SYSERR to abort

Definition at line 133 of file gnunet_datacache_lib.h.

Function Documentation

◆ GNUNET_DATACACHE_create()

struct GNUNET_DATACACHE_Handle* GNUNET_DATACACHE_create ( const struct GNUNET_CONFIGURATION_Handle cfg,
const char *  section 
)

Create a data cache.

Parameters
cfgconfiguration to use
sectionsection in the configuration that contains our options
Returns
handle to use to access the service

Definition at line 128 of file datacache.c.

130 {
131  unsigned int bf_size;
132  unsigned long long quota;
134  char *libname;
135  char *name;
136  const struct GNUNET_OS_ProjectData *pd;
137 
138  if (GNUNET_OK !=
140  section,
141  "QUOTA",
142  &quota))
143  {
145  section,
146  "QUOTA");
147  return NULL;
148  }
149  if (GNUNET_OK !=
151  section,
152  "DATABASE",
153  &name))
154  {
156  section,
157  "DATABASE");
158  return NULL;
159  }
160  bf_size = quota / 32; /* 8 bit per entry, 1 bit per 32 kb in DB */
161 
163 
164  if (GNUNET_YES !=
166  section,
167  "DISABLE_BF"))
168  {
169  if (GNUNET_YES !=
171  section,
172  "DISABLE_BF_RC"))
173  {
174  ret->bloom_name = GNUNET_DISK_mktemp ("gnunet-datacachebloom");
175  }
176  if (NULL != ret->bloom_name)
177  {
179  ret->bloom_name,
180  quota / 1024, /* 8 bit per entry in DB, expect 1k entries */
181  5);
182  }
183  if (NULL == ret->filter)
184  {
185  ret->filter =
187  bf_size,
188  5); /* approx. 3% false positives at max use */
189  }
190  }
191  ret->stats = GNUNET_STATISTICS_create ("datacache",
192  cfg);
193  ret->section = GNUNET_strdup (section);
194  ret->env.cfg = cfg;
195  ret->env.delete_notify = &env_delete_notify;
196  ret->env.section = ret->section;
197  ret->env.cls = ret;
198  ret->env.delete_notify = &env_delete_notify;
199  ret->env.quota = quota;
201  "Loading `%s' datacache plugin\n",
202  name);
204  "libgnunet_plugin_datacache_%s",
205  name);
206  ret->short_name = name;
207  ret->lib_name = libname;
208  /* Load the plugin within GNUnet's default context */
212  &ret->env);
213  GNUNET_OS_init (pd);
214  if (NULL == ret->api)
215  {
216  /* Try to load the plugin within the application's context
217  This normally happens when the application is not GNUnet itself but a
218  third party; inside GNUnet this is effectively a double failure. */
220  &ret->env);
221  if (NULL == ret->api)
222  {
224  "Failed to load datacache plugin for `%s'\n",
225  name);
227  return NULL;
228  }
229  }
230  return ret;
231 }
static void env_delete_notify(void *cls, const struct GNUNET_HashCode *key, size_t size)
Function called by plugins to notify the datacache about content deletions.
Definition: datacache.c:104
#define LOG(kind,...)
Definition: datacache.c:32
static const struct GNUNET_CONFIGURATION_Handle * cfg
Configuration we are using.
Definition: gnunet-abd.c:36
static int ret
Return value of the commandline.
Definition: gnunet-abd.c:81
static unsigned long long quota
How much space are we allowed to use?
struct GNUNET_CONTAINER_BloomFilter * GNUNET_CONTAINER_bloomfilter_load(const char *filename, size_t size, unsigned int k)
Load a Bloom filter from a file.
struct GNUNET_CONTAINER_BloomFilter * GNUNET_CONTAINER_bloomfilter_init(const char *data, size_t size, unsigned int k)
Create a Bloom filter from raw bits.
enum GNUNET_GenericReturnValue GNUNET_CONFIGURATION_get_value_size(const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section, const char *option, unsigned long long *size)
Get a configuration value that should be a size in bytes.
enum GNUNET_GenericReturnValue GNUNET_CONFIGURATION_get_value_yesno(const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section, const char *option)
Get a configuration value that should be in a set of "YES" or "NO".
enum GNUNET_GenericReturnValue GNUNET_CONFIGURATION_get_value_string(const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section, const char *option, char **value)
Get a configuration value that should be a string.
void GNUNET_DATACACHE_destroy(struct GNUNET_DATACACHE_Handle *h)
Destroy a data cache (and free associated resources).
Definition: datacache.c:235
char * GNUNET_DISK_mktemp(const char *t)
Create an (empty) temporary file on disk.
Definition: disk.c:381
@ GNUNET_OK
Definition: gnunet_common.h:99
@ GNUNET_YES
void GNUNET_log_config_missing(enum GNUNET_ErrorType kind, const char *section, const char *option)
Log error message about missing configuration option.
@ GNUNET_ERROR_TYPE_ERROR
@ GNUNET_ERROR_TYPE_INFO
int int GNUNET_asprintf(char **buf, const char *format,...) __attribute__((format(printf
Like asprintf, just portable.
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
const struct GNUNET_OS_ProjectData * GNUNET_OS_project_data_default(void)
Return default project data used by 'libgnunetutil' for GNUnet.
const struct GNUNET_OS_ProjectData * GNUNET_OS_project_data_get(void)
void GNUNET_OS_init(const struct GNUNET_OS_ProjectData *pd)
Setup OS subsystem with project data.
void * GNUNET_PLUGIN_load(const char *library_name, void *arg)
Setup plugin (runs the "init" callback and returns whatever "init" returned).
Definition: plugin.c:197
struct GNUNET_STATISTICS_Handle * GNUNET_STATISTICS_create(const char *subsystem, const struct GNUNET_CONFIGURATION_Handle *cfg)
Get handle for the statistics service.
const char * name
Internal state of the datacache library.
Definition: datacache.c:41
Project-specific data used to help the OS subsystem find installation paths.
const char * libname
Name of a library that is installed in the "lib/" directory of the project, such as "libgnunetutil".

References cfg, env_delete_notify(), GNUNET_asprintf(), GNUNET_CONFIGURATION_get_value_size(), GNUNET_CONFIGURATION_get_value_string(), GNUNET_CONFIGURATION_get_value_yesno(), GNUNET_CONTAINER_bloomfilter_init(), GNUNET_CONTAINER_bloomfilter_load(), GNUNET_DATACACHE_destroy(), GNUNET_DISK_mktemp(), GNUNET_ERROR_TYPE_ERROR, GNUNET_ERROR_TYPE_INFO, GNUNET_log_config_missing(), GNUNET_new, GNUNET_OK, GNUNET_OS_init(), GNUNET_OS_project_data_default(), GNUNET_OS_project_data_get(), GNUNET_PLUGIN_load(), GNUNET_STATISTICS_create(), GNUNET_strdup, GNUNET_YES, GNUNET_OS_ProjectData::libname, LOG, name, quota, and ret.

Referenced by GDS_DATACACHE_init().

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◆ GNUNET_DATACACHE_destroy()

void GNUNET_DATACACHE_destroy ( struct GNUNET_DATACACHE_Handle h)

Destroy a data cache (and free associated resources).

Parameters
hhandle to the datastore

Definition at line 235 of file datacache.c.

236 {
237  if (NULL != h->filter)
239  if (NULL != h->api)
240  GNUNET_break (NULL ==
241  GNUNET_PLUGIN_unload (h->lib_name,
242  h->api));
243  GNUNET_free (h->lib_name);
244  GNUNET_free (h->short_name);
245  GNUNET_free (h->section);
246  if (NULL != h->bloom_name)
247  {
248  if (0 != unlink (h->bloom_name))
250  "datacache",
251  "unlink",
252  h->bloom_name);
253  GNUNET_free (h->bloom_name);
254  }
256  GNUNET_free (h);
257 }
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:99
void GNUNET_CONTAINER_bloomfilter_free(struct GNUNET_CONTAINER_BloomFilter *bf)
Free the space associated with a filter in memory, flush to drive if needed (do not free the space on...
@ GNUNET_NO
Definition: gnunet_common.h:98
#define GNUNET_log_from_strerror_file(level, component, cmd, filename)
Log an error message at log-level 'level' that indicates a failure of the command 'cmd' with the mess...
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur.
@ GNUNET_ERROR_TYPE_WARNING
#define GNUNET_free(ptr)
Wrapper around free.
void * GNUNET_PLUGIN_unload(const char *library_name, void *arg)
Unload plugin (runs the "done" callback and returns whatever "done" returned).
Definition: plugin.c:241
void GNUNET_STATISTICS_destroy(struct GNUNET_STATISTICS_Handle *h, int sync_first)
Destroy a handle (free all state associated with it).

References GNUNET_break, GNUNET_CONTAINER_bloomfilter_free(), GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_log_from_strerror_file, GNUNET_NO, GNUNET_PLUGIN_unload(), GNUNET_STATISTICS_destroy(), and h.

Referenced by GDS_DATACACHE_done(), and GNUNET_DATACACHE_create().

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◆ GNUNET_DATACACHE_put()

enum GNUNET_GenericReturnValue GNUNET_DATACACHE_put ( struct GNUNET_DATACACHE_Handle h,
uint32_t  xor_distance,
const struct GNUNET_DATACACHE_Block block 
)

Store an item in the datacache.

Parameters
hhandle to the datacache
xor_distancehow close is the block's key to our pid?
blockactual block data to store
Returns
GNUNET_OK on success, GNUNET_SYSERR on error, GNUNET_NO if duplicate

Definition at line 235 of file datacache.c.

264 {
265  ssize_t used;
266 
267  used = h->api->put (h->api->cls,
268  xor_distance,
269  block);
270  if (-1 == used)
271  {
272  GNUNET_break (0);
273  return GNUNET_SYSERR;
274  }
275  if (0 == used)
276  {
277  /* duplicate */
278  return GNUNET_NO;
279  }
281  "Stored data under key `%s' in cache\n",
282  GNUNET_h2s (&block->key));
283  if (NULL != h->filter)
285  &block->key);
286  GNUNET_STATISTICS_update (h->stats,
287  "# bytes stored",
288  used,
289  GNUNET_NO);
290  GNUNET_STATISTICS_update (h->stats,
291  "# items stored",
292  1,
293  GNUNET_NO);
294  while (h->utilization + used > h->env.quota)
296  h->api->del (h->api->cls));
297  h->utilization += used;
298  return GNUNET_OK;
299 }
void GNUNET_CONTAINER_bloomfilter_add(struct GNUNET_CONTAINER_BloomFilter *bf, const struct GNUNET_HashCode *e)
Add an element to the filter.
@ GNUNET_SYSERR
Definition: gnunet_common.h:97
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
const char * GNUNET_h2s(const struct GNUNET_HashCode *hc)
Convert a hash value to a string (for printing debug messages).
@ GNUNET_ERROR_TYPE_DEBUG
void GNUNET_STATISTICS_update(struct GNUNET_STATISTICS_Handle *handle, const char *name, int64_t delta, int make_persistent)
Set statistic value for the peer.
struct GNUNET_HashCode key
Key of the block.

Referenced by datacache_get_iterator().

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◆ GNUNET_DATACACHE_get()

unsigned int GNUNET_DATACACHE_get ( struct GNUNET_DATACACHE_Handle h,
const struct GNUNET_HashCode key,
enum GNUNET_BLOCK_Type  type,
GNUNET_DATACACHE_Iterator  iter,
void *  iter_cls 
)

Iterate over the results for a particular key in the datacache.

Parameters
hhandle to the datacache
keywhat to look up
typeentries of which type are relevant?
itermaybe NULL (to just count)
iter_clsclosure for iter
Returns
the number of results found

Definition at line 303 of file datacache.c.

308 {
309  GNUNET_STATISTICS_update (h->stats,
310  "# requests received",
311  1,
312  GNUNET_NO);
314  "Processing request for key `%s'\n",
315  GNUNET_h2s (key));
316  if ( (NULL != h->filter) &&
317  (GNUNET_OK !=
319  key)) )
320  {
321  GNUNET_STATISTICS_update (h->stats,
322  "# requests filtered by bloom filter",
323  1,
324  GNUNET_NO);
326  "Bloomfilter filters request for key `%s'\n",
327  GNUNET_h2s (key));
328  return 0; /* can not be present */
329  }
330  return h->api->get (h->api->cls,
331  key,
332  type,
333  iter, iter_cls);
334 }
struct GNUNET_HashCode key
The key used in the DHT.
bool GNUNET_CONTAINER_bloomfilter_test(const struct GNUNET_CONTAINER_BloomFilter *bf, const struct GNUNET_HashCode *e)
Test if an element is in the filter.
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model

References GNUNET_CONTAINER_bloomfilter_test(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_NO, GNUNET_OK, GNUNET_STATISTICS_update(), h, key, LOG, and type.

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◆ GNUNET_DATACACHE_get_closest()

unsigned int GNUNET_DATACACHE_get_closest ( struct GNUNET_DATACACHE_Handle h,
const struct GNUNET_HashCode key,
enum GNUNET_BLOCK_Type  type,
unsigned int  num_results,
GNUNET_DATACACHE_Iterator  iter,
void *  iter_cls 
)

Iterate over the results that are "close" to a particular key in the datacache.

"close" is defined as numerically larger than key (when interpreted as a circular address space), with small distance.

Parameters
hhandle to the datacache
keyarea of the keyspace to look into
typeentries of which type are relevant?
num_resultsnumber of results that should be returned to iter
itermaybe NULL (to just count)
iter_clsclosure for iter
Returns
the number of results found

Definition at line 338 of file datacache.c.

344 {
345  GNUNET_STATISTICS_update (h->stats,
346  "# proximity search requests received",
347  1,
348  GNUNET_NO);
350  "Processing proximity search at `%s'\n",
351  GNUNET_h2s (key));
352  return h->api->get_closest (h->api->cls,
353  key,
354  type,
355  num_results,
356  iter,
357  iter_cls);
358 }

References GNUNET_ERROR_TYPE_DEBUG, GNUNET_h2s(), GNUNET_NO, GNUNET_STATISTICS_update(), h, key, LOG, and type.

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