1 /* crypto/lhash/lhash.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 /*-
60 * Code for dynamic hash table routines
61 * Author - Eric Young v 2.0
62 *
63 * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
64 * present. eay 18-Jun-98
65 *
66 * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
67 *
68 * 2.0 eay - Fixed a bug that occurred when using lh_delete
69 * from inside lh_doall(). As entries were deleted,
70 * the 'table' was 'contract()ed', making some entries
71 * jump from the end of the table to the start, there by
72 * skipping the lh_doall() processing. eay - 4/12/95
73 *
74 * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
75 * were not being free()ed. 21/11/95
76 *
77 * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
78 * 19/09/95
79 *
80 * 1.7 eay - Removed the fputs() for realloc failures - the code
81 * should silently tolerate them. I have also fixed things
82 * lint complained about 04/05/95
83 *
84 * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
85 *
86 * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
87 *
88 * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
89 *
90 * 1.3 eay - Fixed a few lint problems 19/3/1991
91 *
92 * 1.2 eay - Fixed lh_doall problem 13/3/1991
93 *
94 * 1.1 eay - Added lh_doall
95 *
96 * 1.0 eay - First version
97 */
98 #include <stdio.h>
99 #include <string.h>
100 #include <stdlib.h>
101 #include <openssl/crypto.h>
102 #include <openssl/lhash.h>
103
104 /*
105 * A hashing implementation that appears to be based on the linear hashing
106 * alogrithm:
107 * https://en.wikipedia.org/wiki/Linear_hashing
108 *
109 * Litwin, Witold (1980), "Linear hashing: A new tool for file and table
110 * addressing", Proc. 6th Conference on Very Large Databases: 212-223
111 * http://hackthology.com/pdfs/Litwin-1980-Linear_Hashing.pdf
112 *
113 * From the wikipedia article "Linear hashing is used in the BDB Berkeley
114 * database system, which in turn is used by many software systems such as
115 * OpenLDAP, using a C implementation derived from the CACM article and first
116 * published on the Usenet in 1988 by Esmond Pitt."
117 *
118 * The CACM paper is available here:
119 * https://pdfs.semanticscholar.org/ff4d/1c5deca6269cc316bfd952172284dbf610ee.pdf
120 */
121
122 const char lh_version[] = "lhash" OPENSSL_VERSION_PTEXT;
123
124 #undef MIN_NODES
125 #define MIN_NODES 16
126 #define UP_LOAD (2*LH_LOAD_MULT) /* load times 256 (default 2) */
127 #define DOWN_LOAD (LH_LOAD_MULT) /* load times 256 (default 1) */
128
129 static int expand(_LHASH *lh);
130 static void contract(_LHASH *lh);
131 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash);
132
lh_new(LHASH_HASH_FN_TYPE h,LHASH_COMP_FN_TYPE c)133 _LHASH *lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
134 {
135 _LHASH *ret;
136 int i;
137
138 if ((ret = OPENSSL_malloc(sizeof(_LHASH))) == NULL)
139 goto err0;
140 if ((ret->b = OPENSSL_malloc(sizeof(LHASH_NODE *) * MIN_NODES)) == NULL)
141 goto err1;
142 for (i = 0; i < MIN_NODES; i++)
143 ret->b[i] = NULL;
144 ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
145 ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
146 ret->num_nodes = MIN_NODES / 2;
147 ret->num_alloc_nodes = MIN_NODES;
148 ret->p = 0;
149 ret->pmax = MIN_NODES / 2;
150 ret->up_load = UP_LOAD;
151 ret->down_load = DOWN_LOAD;
152 ret->num_items = 0;
153
154 ret->num_expands = 0;
155 ret->num_expand_reallocs = 0;
156 ret->num_contracts = 0;
157 ret->num_contract_reallocs = 0;
158 ret->num_hash_calls = 0;
159 ret->num_comp_calls = 0;
160 ret->num_insert = 0;
161 ret->num_replace = 0;
162 ret->num_delete = 0;
163 ret->num_no_delete = 0;
164 ret->num_retrieve = 0;
165 ret->num_retrieve_miss = 0;
166 ret->num_hash_comps = 0;
167
168 ret->error = 0;
169 return (ret);
170 err1:
171 OPENSSL_free(ret);
172 err0:
173 return (NULL);
174 }
175
lh_free(_LHASH * lh)176 void lh_free(_LHASH *lh)
177 {
178 unsigned int i;
179 LHASH_NODE *n, *nn;
180
181 if (lh == NULL)
182 return;
183
184 for (i = 0; i < lh->num_nodes; i++) {
185 n = lh->b[i];
186 while (n != NULL) {
187 nn = n->next;
188 OPENSSL_free(n);
189 n = nn;
190 }
191 }
192 OPENSSL_free(lh->b);
193 OPENSSL_free(lh);
194 }
195
lh_insert(_LHASH * lh,void * data)196 void *lh_insert(_LHASH *lh, void *data)
197 {
198 unsigned long hash;
199 LHASH_NODE *nn, **rn;
200 void *ret;
201
202 lh->error = 0;
203 if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)
204 && !expand(lh))
205 return NULL;
206
207 rn = getrn(lh, data, &hash);
208
209 if (*rn == NULL) {
210 if ((nn = (LHASH_NODE *)OPENSSL_malloc(sizeof(LHASH_NODE))) == NULL) {
211 lh->error++;
212 return (NULL);
213 }
214 nn->data = data;
215 nn->next = NULL;
216 #ifndef OPENSSL_NO_HASH_COMP
217 nn->hash = hash;
218 #endif
219 *rn = nn;
220 ret = NULL;
221 lh->num_insert++;
222 lh->num_items++;
223 } else { /* replace same key */
224
225 ret = (*rn)->data;
226 (*rn)->data = data;
227 lh->num_replace++;
228 }
229 return (ret);
230 }
231
lh_delete(_LHASH * lh,const void * data)232 void *lh_delete(_LHASH *lh, const void *data)
233 {
234 unsigned long hash;
235 LHASH_NODE *nn, **rn;
236 void *ret;
237
238 lh->error = 0;
239 rn = getrn(lh, data, &hash);
240
241 if (*rn == NULL) {
242 lh->num_no_delete++;
243 return (NULL);
244 } else {
245 nn = *rn;
246 *rn = nn->next;
247 ret = nn->data;
248 OPENSSL_free(nn);
249 lh->num_delete++;
250 }
251
252 lh->num_items--;
253 if ((lh->num_nodes > MIN_NODES) &&
254 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
255 contract(lh);
256
257 return (ret);
258 }
259
lh_retrieve(_LHASH * lh,const void * data)260 void *lh_retrieve(_LHASH *lh, const void *data)
261 {
262 unsigned long hash;
263 LHASH_NODE **rn;
264 void *ret;
265
266 lh->error = 0;
267 rn = getrn(lh, data, &hash);
268
269 if (*rn == NULL) {
270 lh->num_retrieve_miss++;
271 return (NULL);
272 } else {
273 ret = (*rn)->data;
274 lh->num_retrieve++;
275 }
276 return (ret);
277 }
278
doall_util_fn(_LHASH * lh,int use_arg,LHASH_DOALL_FN_TYPE func,LHASH_DOALL_ARG_FN_TYPE func_arg,void * arg)279 static void doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
280 LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
281 {
282 int i;
283 LHASH_NODE *a, *n;
284
285 if (lh == NULL)
286 return;
287
288 /*
289 * reverse the order so we search from 'top to bottom' We were having
290 * memory leaks otherwise
291 */
292 for (i = lh->num_nodes - 1; i >= 0; i--) {
293 a = lh->b[i];
294 while (a != NULL) {
295 /*
296 * 28/05/91 - eay - n added so items can be deleted via lh_doall
297 */
298 /*
299 * 22/05/08 - ben - eh? since a is not passed, this should not be
300 * needed
301 */
302 n = a->next;
303 if (use_arg)
304 func_arg(a->data, arg);
305 else
306 func(a->data);
307 a = n;
308 }
309 }
310 }
311
lh_doall(_LHASH * lh,LHASH_DOALL_FN_TYPE func)312 void lh_doall(_LHASH *lh, LHASH_DOALL_FN_TYPE func)
313 {
314 doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
315 }
316
lh_doall_arg(_LHASH * lh,LHASH_DOALL_ARG_FN_TYPE func,void * arg)317 void lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
318 {
319 doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
320 }
321
expand(_LHASH * lh)322 static int expand(_LHASH *lh)
323 {
324 LHASH_NODE **n, **n1, **n2, *np;
325 unsigned int p, pmax, nni, j;
326 unsigned long hash;
327
328 nni = lh->num_alloc_nodes;
329 p = lh->p;
330 pmax = lh->pmax;
331 if (p + 1 >= pmax) {
332 j = nni * 2;
333 n = OPENSSL_realloc(lh->b, (int)(sizeof(LHASH_NODE *) * j));
334 if (n == NULL) {
335 lh->error++;
336 return 0;
337 }
338 lh->b = n;
339 memset(n + nni, 0, sizeof(*n) * (j - nni));
340 lh->pmax = nni;
341 lh->num_alloc_nodes = j;
342 lh->num_expand_reallocs++;
343 lh->p = 0;
344 } else {
345 lh->p++;
346 }
347
348 lh->num_nodes++;
349 lh->num_expands++;
350 n1 = &(lh->b[p]);
351 n2 = &(lh->b[p + pmax]);
352 *n2 = NULL;
353
354 for (np = *n1; np != NULL;) {
355 #ifndef OPENSSL_NO_HASH_COMP
356 hash = np->hash;
357 #else
358 hash = lh->hash(np->data);
359 lh->num_hash_calls++;
360 #endif
361 if ((hash % nni) != p) { /* move it */
362 *n1 = (*n1)->next;
363 np->next = *n2;
364 *n2 = np;
365 } else
366 n1 = &((*n1)->next);
367 np = *n1;
368 }
369
370 return 1;
371 }
372
contract(_LHASH * lh)373 static void contract(_LHASH *lh)
374 {
375 LHASH_NODE **n, *n1, *np;
376
377 np = lh->b[lh->p + lh->pmax - 1];
378 lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
379 if (lh->p == 0) {
380 n = (LHASH_NODE **)OPENSSL_realloc(lh->b,
381 (unsigned int)(sizeof(LHASH_NODE *)
382 * lh->pmax));
383 if (n == NULL) {
384 /* fputs("realloc error in lhash",stderr); */
385 lh->error++;
386 return;
387 }
388 lh->num_contract_reallocs++;
389 lh->num_alloc_nodes /= 2;
390 lh->pmax /= 2;
391 lh->p = lh->pmax - 1;
392 lh->b = n;
393 } else
394 lh->p--;
395
396 lh->num_nodes--;
397 lh->num_contracts++;
398
399 n1 = lh->b[(int)lh->p];
400 if (n1 == NULL)
401 lh->b[(int)lh->p] = np;
402 else {
403 while (n1->next != NULL)
404 n1 = n1->next;
405 n1->next = np;
406 }
407 }
408
getrn(_LHASH * lh,const void * data,unsigned long * rhash)409 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash)
410 {
411 LHASH_NODE **ret, *n1;
412 unsigned long hash, nn;
413 LHASH_COMP_FN_TYPE cf;
414
415 hash = (*(lh->hash)) (data);
416 lh->num_hash_calls++;
417 *rhash = hash;
418
419 nn = hash % lh->pmax;
420 if (nn < lh->p)
421 nn = hash % lh->num_alloc_nodes;
422
423 cf = lh->comp;
424 ret = &(lh->b[(int)nn]);
425 for (n1 = *ret; n1 != NULL; n1 = n1->next) {
426 #ifndef OPENSSL_NO_HASH_COMP
427 lh->num_hash_comps++;
428 if (n1->hash != hash) {
429 ret = &(n1->next);
430 continue;
431 }
432 #endif
433 lh->num_comp_calls++;
434 if (cf(n1->data, data) == 0)
435 break;
436 ret = &(n1->next);
437 }
438 return (ret);
439 }
440
441 /*
442 * The following hash seems to work very well on normal text strings no
443 * collisions on /usr/dict/words and it distributes on %2^n quite well, not
444 * as good as MD5, but still good.
445 */
lh_strhash(const char * c)446 unsigned long lh_strhash(const char *c)
447 {
448 unsigned long ret = 0;
449 long n;
450 unsigned long v;
451 int r;
452
453 if ((c == NULL) || (*c == '\0'))
454 return (ret);
455 /*-
456 unsigned char b[16];
457 MD5(c,strlen(c),b);
458 return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
459 */
460
461 n = 0x100;
462 while (*c) {
463 v = n | (*c);
464 n += 0x100;
465 r = (int)((v >> 2) ^ v) & 0x0f;
466 ret = (ret << r) | (ret >> (32 - r));
467 ret &= 0xFFFFFFFFL;
468 ret ^= v * v;
469 c++;
470 }
471 return ((ret >> 16) ^ ret);
472 }
473
lh_num_items(const _LHASH * lh)474 unsigned long lh_num_items(const _LHASH *lh)
475 {
476 return lh ? lh->num_items : 0;
477 }
478