GNUnet  0.10.x
ibf.c
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1 /*
2  This file is part of GNUnet
3  Copyright (C) 2012 GNUnet e.V.
4 
5  GNUnet is free software: you can redistribute it and/or modify it
6  under the terms of the GNU Affero General Public License as published
7  by the Free Software Foundation, either version 3 of the License,
8  or (at your option) any later version.
9 
10  GNUnet is distributed in the hope that it will be useful, but
11  WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  Affero General Public License for more details.
14 
15  You should have received a copy of the GNU Affero General Public License
16  along with this program. If not, see <http://www.gnu.org/licenses/>.
17 
18  SPDX-License-Identifier: AGPL3.0-or-later
19 */
20 
27 #include "ibf.h"
28 
33 #define IBF_KEY_HASH_VAL(k) (GNUNET_CRYPTO_crc32_n (&(k), sizeof (struct IBF_KeyHash)))
34 
41 struct IBF_Key
43 {
44  return *(struct IBF_Key *) hash;
45 }
46 
54 void
56  struct GNUNET_HashCode *dst)
57 {
58  struct IBF_Key *p;
59  unsigned int i;
60  const unsigned int keys_per_hashcode = sizeof (struct GNUNET_HashCode) / sizeof (struct IBF_Key);
61 
62  p = (struct IBF_Key *) dst;
63  for (i = 0; i < keys_per_hashcode; i++)
64  *p++ = key;
65 }
66 
67 
75 struct InvertibleBloomFilter *
76 ibf_create (uint32_t size, uint8_t hash_num)
77 {
78  struct InvertibleBloomFilter *ibf;
79 
80  GNUNET_assert (0 != size);
81 
82  ibf = GNUNET_new (struct InvertibleBloomFilter);
83  ibf->count = GNUNET_malloc_large (size * sizeof (uint8_t));
84  if (NULL == ibf->count)
85  {
86  GNUNET_free (ibf);
87  return NULL;
88  }
89  ibf->key_sum = GNUNET_malloc_large (size * sizeof (struct IBF_Key));
90  if (NULL == ibf->key_sum)
91  {
92  GNUNET_free (ibf->count);
93  GNUNET_free (ibf);
94  return NULL;
95  }
96  ibf->key_hash_sum = GNUNET_malloc_large (size * sizeof (struct IBF_KeyHash));
97  if (NULL == ibf->key_hash_sum)
98  {
99  GNUNET_free (ibf->key_sum);
100  GNUNET_free (ibf->count);
101  GNUNET_free (ibf);
102  return NULL;
103  }
104  ibf->size = size;
105  ibf->hash_num = hash_num;
106 
107  return ibf;
108 }
109 
110 
114 static void
116  struct IBF_Key key,
117  int *dst)
118 {
119  uint32_t filled;
120  uint32_t i;
121  uint32_t bucket;
122 
123  bucket = GNUNET_CRYPTO_crc32_n (&key, sizeof key);
124  for (i = 0, filled=0; filled < ibf->hash_num; i++)
125  {
126  unsigned int j;
127  uint64_t x;
128  for (j = 0; j < filled; j++)
129  if (dst[j] == bucket)
130  goto try_next;
131  dst[filled++] = bucket % ibf->size;
132  try_next: ;
133  x = ((uint64_t) bucket << 32) | i;
134  bucket = GNUNET_CRYPTO_crc32_n (&x, sizeof x);
135  }
136 }
137 
138 
139 static void
141  struct IBF_Key key,
142  const int *buckets, int side)
143 {
144  int i;
145 
146  for (i = 0; i < ibf->hash_num; i++)
147  {
148  const int bucket = buckets[i];
149  ibf->count[bucket].count_val += side;
150  ibf->key_sum[bucket].key_val ^= key.key_val;
151  ibf->key_hash_sum[bucket].key_hash_val
152  ^= IBF_KEY_HASH_VAL (key);
153  }
154 }
155 
156 
163 void
165 {
166  int buckets[ibf->hash_num];
167  GNUNET_assert (ibf->hash_num <= ibf->size);
168  ibf_get_indices (ibf, key, buckets);
169  ibf_insert_into (ibf, key, buckets, 1);
170 }
171 
172 
179 void
181 {
182  int buckets[ibf->hash_num];
183  GNUNET_assert (ibf->hash_num <= ibf->size);
184  ibf_get_indices (ibf, key, buckets);
185  ibf_insert_into (ibf, key, buckets, -1);
186 }
187 
188 
192 static int
194 {
195  int i;
196  for (i = 0; i < ibf->size; i++)
197  {
198  if (0 != ibf->count[i].count_val)
199  return GNUNET_NO;
200  if (0 != ibf->key_hash_sum[i].key_hash_val)
201  return GNUNET_NO;
202  if (0 != ibf->key_sum[i].key_val)
203  return GNUNET_NO;
204  }
205  return GNUNET_YES;
206 }
207 
208 
221 int
223  int *ret_side, struct IBF_Key *ret_id)
224 {
225  struct IBF_KeyHash hash;
226  int i;
227  int buckets[ibf->hash_num];
228 
229  GNUNET_assert (NULL != ibf);
230 
231  for (i = 0; i < ibf->size; i++)
232  {
233  int j;
234  int hit;
235 
236  /* we can only decode from pure buckets */
237  if ((1 != ibf->count[i].count_val) && (-1 != ibf->count[i].count_val))
238  continue;
239 
240  hash.key_hash_val = IBF_KEY_HASH_VAL (ibf->key_sum[i]);
241 
242  /* test if the hash matches the key */
243  if (hash.key_hash_val != ibf->key_hash_sum[i].key_hash_val)
244  continue;
245 
246  /* test if key in bucket hits its own location,
247  * if not, the key hash was subject to collision */
248  hit = GNUNET_NO;
249  ibf_get_indices (ibf, ibf->key_sum[i], buckets);
250  for (j = 0; j < ibf->hash_num; j++)
251  if (buckets[j] == i)
252  hit = GNUNET_YES;
253 
254  if (GNUNET_NO == hit)
255  continue;
256 
257  if (NULL != ret_side)
258  *ret_side = ibf->count[i].count_val;
259  if (NULL != ret_id)
260  *ret_id = ibf->key_sum[i];
261 
262  /* insert on the opposite side, effectively removing the element */
263  ibf_insert_into (ibf, ibf->key_sum[i], buckets, -ibf->count[i].count_val);
264 
265  return GNUNET_YES;
266  }
267 
268  if (GNUNET_YES == ibf_is_empty (ibf))
269  return GNUNET_NO;
270  return GNUNET_SYSERR;
271 }
272 
273 
283 void
284 ibf_write_slice (const struct InvertibleBloomFilter *ibf, uint32_t start, uint32_t count, void *buf)
285 {
286  struct IBF_Key *key_dst;
287  struct IBF_KeyHash *key_hash_dst;
288  struct IBF_Count *count_dst;
289 
290  GNUNET_assert (start + count <= ibf->size);
291 
292  /* copy keys */
293  key_dst = (struct IBF_Key *) buf;
294  GNUNET_memcpy (key_dst, ibf->key_sum + start, count * sizeof *key_dst);
295  key_dst += count;
296  /* copy key hashes */
297  key_hash_dst = (struct IBF_KeyHash *) key_dst;
298  GNUNET_memcpy (key_hash_dst, ibf->key_hash_sum + start, count * sizeof *key_hash_dst);
299  key_hash_dst += count;
300  /* copy counts */
301  count_dst = (struct IBF_Count *) key_hash_dst;
302  GNUNET_memcpy (count_dst, ibf->count + start, count * sizeof *count_dst);
303 }
304 
305 
314 void
315 ibf_read_slice (const void *buf, uint32_t start, uint32_t count, struct InvertibleBloomFilter *ibf)
316 {
317  struct IBF_Key *key_src;
318  struct IBF_KeyHash *key_hash_src;
319  struct IBF_Count *count_src;
320 
321  GNUNET_assert (count > 0);
322  GNUNET_assert (start + count <= ibf->size);
323 
324  /* copy keys */
325  key_src = (struct IBF_Key *) buf;
326  GNUNET_memcpy (ibf->key_sum + start, key_src, count * sizeof *key_src);
327  key_src += count;
328  /* copy key hashes */
329  key_hash_src = (struct IBF_KeyHash *) key_src;
330  GNUNET_memcpy (ibf->key_hash_sum + start, key_hash_src, count * sizeof *key_hash_src);
331  key_hash_src += count;
332  /* copy counts */
333  count_src = (struct IBF_Count *) key_hash_src;
334  GNUNET_memcpy (ibf->count + start, count_src, count * sizeof *count_src);
335 }
336 
337 
345 void
346 ibf_subtract (struct InvertibleBloomFilter *ibf1, const struct InvertibleBloomFilter *ibf2)
347 {
348  int i;
349 
350  GNUNET_assert (ibf1->size == ibf2->size);
351  GNUNET_assert (ibf1->hash_num == ibf2->hash_num);
352 
353  for (i = 0; i < ibf1->size; i++)
354  {
355  ibf1->count[i].count_val -= ibf2->count[i].count_val;
356  ibf1->key_hash_sum[i].key_hash_val ^= ibf2->key_hash_sum[i].key_hash_val;
357  ibf1->key_sum[i].key_val ^= ibf2->key_sum[i].key_val;
358  }
359 }
360 
361 
367 struct InvertibleBloomFilter *
368 ibf_dup (const struct InvertibleBloomFilter *ibf)
369 {
370  struct InvertibleBloomFilter *copy;
371  copy = GNUNET_malloc (sizeof *copy);
372  copy->hash_num = ibf->hash_num;
373  copy->size = ibf->size;
374  copy->key_hash_sum = GNUNET_memdup (ibf->key_hash_sum, ibf->size * sizeof (struct IBF_KeyHash));
375  copy->key_sum = GNUNET_memdup (ibf->key_sum, ibf->size * sizeof (struct IBF_Key));
376  copy->count = GNUNET_memdup (ibf->count, ibf->size * sizeof (struct IBF_Count));
377  return copy;
378 }
379 
380 
387 void
389 {
390  GNUNET_free (ibf->key_sum);
391  GNUNET_free (ibf->key_hash_sum);
392  GNUNET_free (ibf->count);
393  GNUNET_free (ibf);
394 }
void ibf_remove(struct InvertibleBloomFilter *ibf, struct IBF_Key key)
Remove a key from an IBF.
Definition: ibf.c:180
int32_t GNUNET_CRYPTO_crc32_n(const void *buf, size_t len)
Compute the CRC32 checksum for the first len bytes of the buffer.
Definition: crypto_crc.c:105
struct IBF_Key * key_sum
Xor sums of the elements&#39; keys, used to identify the elements.
Definition: ibf.h:99
static int start
Set if we are to start default services (including ARM).
Definition: gnunet-arm.c:39
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
Invertible bloom filter (IBF).
Definition: ibf.h:82
static void ibf_insert_into(struct InvertibleBloomFilter *ibf, struct IBF_Key key, const int *buckets, int side)
Definition: ibf.c:140
#define GNUNET_NO
Definition: gnunet_common.h:81
#define GNUNET_memdup(buf, size)
Allocate and initialize a block of memory.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
uint64_t key_val
Definition: ibf.h:47
void ibf_write_slice(const struct InvertibleBloomFilter *ibf, uint32_t start, uint32_t count, void *buf)
Write buckets from an ibf to a buffer.
Definition: ibf.c:284
#define GNUNET_malloc_large(size)
Wrapper around malloc.
struct InvertibleBloomFilter * ibf_dup(const struct InvertibleBloomFilter *ibf)
Create a copy of an IBF, the copy has to be destroyed properly.
Definition: ibf.c:368
uint32_t size
How many cells does this IBF have?
Definition: ibf.h:87
#define GNUNET_memcpy(dst, src, n)
static struct GNUNET_OS_Process * p
Helper process we started.
Definition: gnunet-qr.c:59
uint32_t key_hash_val
Definition: ibf.h:56
int ibf_decode(struct InvertibleBloomFilter *ibf, int *ret_side, struct IBF_Key *ret_id)
Decode and remove an element from the IBF, if possible.
Definition: ibf.c:222
void ibf_hashcode_from_key(struct IBF_Key key, struct GNUNET_HashCode *dst)
Create a hashcode from a key, by replicating the key until the hascode is filled. ...
Definition: ibf.c:55
static char buf[2048]
uint8_t hash_num
In how many cells do we hash one element? Usually 4 or 3.
Definition: ibf.h:93
void ibf_subtract(struct InvertibleBloomFilter *ibf1, const struct InvertibleBloomFilter *ibf2)
Subtract ibf2 from ibf1, storing the result in ibf1.
Definition: ibf.c:346
#define IBF_KEY_HASH_VAL(k)
Compute the key&#39;s hash from the key.
Definition: ibf.c:33
A 512-bit hashcode.
Type of the count field of IBF buckets.
Definition: ibf.h:63
struct IBF_KeyHash * key_hash_sum
Xor sums of the hashes of the keys of inserted elements.
Definition: ibf.h:105
void ibf_read_slice(const void *buf, uint32_t start, uint32_t count, struct InvertibleBloomFilter *ibf)
Read buckets from a buffer into an ibf.
Definition: ibf.c:315
struct GNUNET_HashCode key
The key used in the DHT.
#define GNUNET_SYSERR
Definition: gnunet_common.h:79
invertible bloom filter
static unsigned int size
Size of the "table".
Definition: peer.c:67
void ibf_destroy(struct InvertibleBloomFilter *ibf)
Destroy all resources associated with the invertible bloom filter.
Definition: ibf.c:388
static unsigned int hash_num
Hash of an IBF key.
Definition: ibf.h:54
struct InvertibleBloomFilter * ibf_create(uint32_t size, uint8_t hash_num)
Create an invertible bloom filter.
Definition: ibf.c:76
void ibf_insert(struct InvertibleBloomFilter *ibf, struct IBF_Key key)
Insert a key into an IBF.
Definition: ibf.c:164
static void ibf_get_indices(const struct InvertibleBloomFilter *ibf, struct IBF_Key key, int *dst)
Store unique bucket indices for the specified key in dst.
Definition: ibf.c:115
int8_t count_val
Definition: ibf.h:65
#define GNUNET_YES
Definition: gnunet_common.h:80
static int ibf_is_empty(struct InvertibleBloomFilter *ibf)
Test is the IBF is empty, i.e.
Definition: ibf.c:193
struct IBF_Key ibf_key_from_hashcode(const struct GNUNET_HashCode *hash)
Create a key from a hashcode.
Definition: ibf.c:42
Keys that can be inserted into and removed from an IBF.
Definition: ibf.h:45
struct IBF_Count * count
How many times has a bucket been hit? Can be negative, as a result of IBF subtraction.
Definition: ibf.h:112
#define GNUNET_malloc(size)
Wrapper around malloc.
#define GNUNET_free(ptr)
Wrapper around free.