1 /* $OpenBSD: lhash.c,v 1.28 2024/07/14 14:32:45 jsing Exp $ */
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 #include <stdio.h>
60 #include <string.h>
61 #include <stdlib.h>
62
63 #include <openssl/opensslconf.h>
64
65 #include <openssl/crypto.h>
66 #include <openssl/lhash.h>
67
68 #undef MIN_NODES
69 #define MIN_NODES 16
70 #define UP_LOAD (2*LH_LOAD_MULT) /* load times 256 (default 2) */
71 #define DOWN_LOAD (LH_LOAD_MULT) /* load times 256 (default 1) */
72
73 typedef struct lhash_node_st {
74 void *data;
75 struct lhash_node_st *next;
76 #ifndef OPENSSL_NO_HASH_COMP
77 unsigned long hash;
78 #endif
79 } LHASH_NODE;
80
81 struct lhash_st {
82 LHASH_NODE **b;
83 LHASH_COMP_FN_TYPE comp;
84 LHASH_HASH_FN_TYPE hash;
85 unsigned int num_nodes;
86 unsigned int num_alloc_nodes;
87 unsigned int p;
88 unsigned int pmax;
89 unsigned long up_load; /* load times 256 */
90 unsigned long down_load; /* load times 256 */
91 unsigned long num_items;
92
93 int error;
94 } /* _LHASH */;
95
96 static void
expand(_LHASH * lh)97 expand(_LHASH *lh)
98 {
99 LHASH_NODE **n, **n1, **n2, *np;
100 unsigned int p, i, j;
101 unsigned long hash, nni;
102
103 lh->num_nodes++;
104 p = (int)lh->p++;
105 n1 = &(lh->b[p]);
106 n2 = &(lh->b[p + (int)lh->pmax]);
107 *n2 = NULL; /* 27/07/92 - eay - undefined pointer bug */
108 nni = lh->num_alloc_nodes;
109
110 for (np = *n1; np != NULL; ) {
111 #ifndef OPENSSL_NO_HASH_COMP
112 hash = np->hash;
113 #else
114 hash = lh->hash(np->data);
115 #endif
116 if ((hash % nni) != p) { /* move it */
117 *n1 = (*n1)->next;
118 np->next= *n2;
119 *n2 = np;
120 } else
121 n1 = &((*n1)->next);
122 np= *n1;
123 }
124
125 if ((lh->p) >= lh->pmax) {
126 j = (int)lh->num_alloc_nodes * 2;
127 n = reallocarray(lh->b, j, sizeof(LHASH_NODE *));
128 if (n == NULL) {
129 /* fputs("realloc error in lhash", stderr); */
130 lh->error++;
131 lh->p = 0;
132 return;
133 }
134 /* else */
135 for (i = (int)lh->num_alloc_nodes; i < j; i++)/* 26/02/92 eay */
136 n[i] = NULL; /* 02/03/92 eay */
137 lh->pmax = lh->num_alloc_nodes;
138 lh->num_alloc_nodes = j;
139 lh->p = 0;
140 lh->b = n;
141 }
142 }
143
144 static void
contract(_LHASH * lh)145 contract(_LHASH *lh)
146 {
147 LHASH_NODE **n, *n1, *np;
148
149 np = lh->b[lh->p + lh->pmax - 1];
150 lh->b[lh->p+lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
151 if (lh->p == 0) {
152 n = reallocarray(lh->b, lh->pmax, sizeof(LHASH_NODE *));
153 if (n == NULL) {
154 /* fputs("realloc error in lhash", stderr); */
155 lh->error++;
156 return;
157 }
158 lh->num_alloc_nodes /= 2;
159 lh->pmax /= 2;
160 lh->p = lh->pmax - 1;
161 lh->b = n;
162 } else
163 lh->p--;
164
165 lh->num_nodes--;
166
167 n1 = lh->b[(int)lh->p];
168 if (n1 == NULL)
169 lh->b[(int)lh->p] = np;
170 else {
171 while (n1->next != NULL)
172 n1 = n1->next;
173 n1->next = np;
174 }
175 }
176
177 static LHASH_NODE **
getrn(_LHASH * lh,const void * data,unsigned long * rhash)178 getrn(_LHASH *lh, const void *data, unsigned long *rhash)
179 {
180 LHASH_NODE **ret, *n1;
181 unsigned long hash, nn;
182 LHASH_COMP_FN_TYPE cf;
183
184 hash = (*(lh->hash))(data);
185 *rhash = hash;
186
187 nn = hash % lh->pmax;
188 if (nn < lh->p)
189 nn = hash % lh->num_alloc_nodes;
190
191 cf = lh->comp;
192 ret = &(lh->b[(int)nn]);
193 for (n1 = *ret; n1 != NULL; n1 = n1->next) {
194 #ifndef OPENSSL_NO_HASH_COMP
195 if (n1->hash != hash) {
196 ret = &(n1->next);
197 continue;
198 }
199 #endif
200 if (cf(n1->data, data) == 0)
201 break;
202 ret = &(n1->next);
203 }
204 return (ret);
205 }
206
207 _LHASH *
lh_new(LHASH_HASH_FN_TYPE h,LHASH_COMP_FN_TYPE c)208 lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
209 {
210 _LHASH *ret;
211
212 if ((ret = calloc(1, sizeof(_LHASH))) == NULL)
213 return NULL;
214 if ((ret->b = calloc(MIN_NODES, sizeof(LHASH_NODE *))) == NULL) {
215 free(ret);
216 return NULL;
217 }
218 ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
219 ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
220 ret->num_nodes = MIN_NODES / 2;
221 ret->num_alloc_nodes = MIN_NODES;
222 ret->pmax = MIN_NODES / 2;
223 ret->up_load = UP_LOAD;
224 ret->down_load = DOWN_LOAD;
225
226 return (ret);
227 }
228 LCRYPTO_ALIAS(lh_new);
229
230 void
lh_free(_LHASH * lh)231 lh_free(_LHASH *lh)
232 {
233 unsigned int i;
234 LHASH_NODE *n, *nn;
235
236 if (lh == NULL)
237 return;
238
239 for (i = 0; i < lh->num_nodes; i++) {
240 n = lh->b[i];
241 while (n != NULL) {
242 nn = n->next;
243 free(n);
244 n = nn;
245 }
246 }
247 free(lh->b);
248 free(lh);
249 }
250 LCRYPTO_ALIAS(lh_free);
251
252 int
lh_error(_LHASH * lh)253 lh_error(_LHASH *lh)
254 {
255 return lh->error;
256 }
257 LCRYPTO_ALIAS(lh_error);
258
259 void *
lh_insert(_LHASH * lh,void * data)260 lh_insert(_LHASH *lh, void *data)
261 {
262 unsigned long hash;
263 LHASH_NODE *nn, **rn;
264 void *ret;
265
266 lh->error = 0;
267 if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes))
268 expand(lh);
269
270 rn = getrn(lh, data, &hash);
271
272 if (*rn == NULL) {
273 if ((nn = malloc(sizeof(LHASH_NODE))) == NULL) {
274 lh->error++;
275 return (NULL);
276 }
277 nn->data = data;
278 nn->next = NULL;
279 #ifndef OPENSSL_NO_HASH_COMP
280 nn->hash = hash;
281 #endif
282 *rn = nn;
283 ret = NULL;
284 lh->num_items++;
285 }
286 else /* replace same key */
287 {
288 ret = (*rn)->data;
289 (*rn)->data = data;
290 }
291 return (ret);
292 }
293 LCRYPTO_ALIAS(lh_insert);
294
295 void *
lh_delete(_LHASH * lh,const void * data)296 lh_delete(_LHASH *lh, const void *data)
297 {
298 unsigned long hash;
299 LHASH_NODE *nn, **rn;
300 void *ret;
301
302 lh->error = 0;
303 rn = getrn(lh, data, &hash);
304
305 if (*rn == NULL) {
306 return (NULL);
307 } else {
308 nn= *rn;
309 *rn = nn->next;
310 ret = nn->data;
311 free(nn);
312 }
313
314 lh->num_items--;
315 if ((lh->num_nodes > MIN_NODES) &&
316 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
317 contract(lh);
318
319 return (ret);
320 }
321 LCRYPTO_ALIAS(lh_delete);
322
323 void *
lh_retrieve(_LHASH * lh,const void * data)324 lh_retrieve(_LHASH *lh, const void *data)
325 {
326 unsigned long hash;
327 LHASH_NODE **rn;
328 void *ret;
329
330 lh->error = 0;
331 rn = getrn(lh, data, &hash);
332
333 if (*rn == NULL) {
334 return (NULL);
335 } else {
336 ret = (*rn)->data;
337 }
338 return (ret);
339 }
340 LCRYPTO_ALIAS(lh_retrieve);
341
342 static void
doall_util_fn(_LHASH * lh,int use_arg,LHASH_DOALL_FN_TYPE func,LHASH_DOALL_ARG_FN_TYPE func_arg,void * arg)343 doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
344 LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
345 {
346 LHASH_NODE *a, *n;
347 int down_load;
348 int i;
349
350 if (lh == NULL)
351 return;
352
353 /*
354 * Disable contraction of the hash while walking, as some consumers use
355 * it to delete hash entries. A better option would be to snapshot the
356 * hash, making it insert safe as well.
357 */
358 down_load = lh->down_load;
359 lh->down_load = 0;
360
361 /* reverse the order so we search from 'top to bottom'
362 * We were having memory leaks otherwise */
363 for (i = lh->num_nodes - 1; i >= 0; i--) {
364 a = lh->b[i];
365 while (a != NULL) {
366 /* 28/05/91 - eay - n added so items can be deleted
367 * via lh_doall */
368 /* 22/05/08 - ben - eh? since a is not passed,
369 * this should not be needed */
370 n = a->next;
371 if (use_arg)
372 func_arg(a->data, arg);
373 else
374 func(a->data);
375 a = n;
376 }
377 }
378
379 /* Restore down load factor and trigger contraction. */
380 lh->down_load = down_load;
381 if ((lh->num_nodes > MIN_NODES) &&
382 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
383 contract(lh);
384 }
385
386 void
lh_doall(_LHASH * lh,LHASH_DOALL_FN_TYPE func)387 lh_doall(_LHASH *lh, LHASH_DOALL_FN_TYPE func)
388 {
389 doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
390 }
391 LCRYPTO_ALIAS(lh_doall);
392
393 void
lh_doall_arg(_LHASH * lh,LHASH_DOALL_ARG_FN_TYPE func,void * arg)394 lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
395 {
396 doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
397 }
398 LCRYPTO_ALIAS(lh_doall_arg);
399
400 /* The following hash seems to work very well on normal text strings
401 * no collisions on /usr/dict/words and it distributes on %2^n quite
402 * well, not as good as MD5, but still good.
403 */
404 unsigned long
lh_strhash(const char * c)405 lh_strhash(const char *c)
406 {
407 unsigned long ret = 0;
408 unsigned long n, v;
409 unsigned int r;
410
411 if (c == NULL || *c == '\0')
412 return ret;
413
414 n = 0x100;
415 while (*c) {
416 v = n | *c;
417 n += 0x100;
418 if ((r = ((v >> 2) ^ v) & 0x0f) != 0)
419 ret = (ret << r) | (ret >> (32 - r));
420 ret &= 0xFFFFFFFFUL;
421 ret ^= v * v;
422 c++;
423 }
424 return (ret >> 16) ^ ret;
425 }
426 LCRYPTO_ALIAS(lh_strhash);
427
428 unsigned long
lh_num_items(const _LHASH * lh)429 lh_num_items(const _LHASH *lh)
430 {
431 return lh ? lh->num_items : 0;
432 }
433 LCRYPTO_ALIAS(lh_num_items);
434