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526e7c1d P |
1 | /* |
2 | * $Id: patricia.c,v 1.7 2005/12/07 20:46:41 dplonka Exp $ | |
3 | * Dave Plonka <plonka@doit.wisc.edu> | |
4 | * | |
5 | * This product includes software developed by the University of Michigan, | |
6 | * Merit Network, Inc., and their contributors. | |
7 | * | |
8 | * This file had been called "radix.c" in the MRT sources. | |
9 | * | |
10 | * I renamed it to "patricia.c" since it's not an implementation of a general | |
11 | * radix trie. Also I pulled in various requirements from "prefix.c" and | |
12 | * "demo.c" so that it could be used as a standalone API. | |
13 | */ | |
14 | ||
15 | static char copyright[] = | |
16 | "This product includes software developed by the University of Michigan, Merit" | |
17 | "Network, Inc., and their contributors."; | |
18 | ||
19 | #include <malloc.h> | |
20 | #include <assert.h> /* assert */ | |
21 | #include <ctype.h> /* isdigit */ | |
22 | #include <errno.h> /* errno */ | |
23 | #include <math.h> /* sin */ | |
24 | #include <stddef.h> /* NULL */ | |
25 | #include <stdio.h> /* sprintf, fprintf, stderr */ | |
26 | #include <stdlib.h> /* free, atol, calloc */ | |
27 | #include <string.h> /* memcpy, strchr, strlen */ | |
28 | ||
29 | #include "patricia.h" | |
30 | ||
31 | /* { from prefix.c */ | |
32 | ||
33 | /* prefix_tochar | |
34 | * convert prefix information to bytes | |
35 | */ | |
36 | u_char * | |
37 | prefix_tochar (prefix_t * prefix) | |
38 | { | |
39 | if (prefix == NULL) | |
40 | return (NULL); | |
41 | ||
42 | return ((u_char *) & prefix->sin); | |
43 | } | |
44 | ||
45 | int | |
46 | comp_with_mask (void *addr, void *dest, u_int mask) | |
47 | { | |
48 | ||
49 | if ( /* mask/8 == 0 || */ memcmp (addr, dest, mask / 8) == 0) { | |
50 | int n = mask / 8; | |
51 | int m = ((-1) << (8 - (mask % 8))); | |
52 | ||
53 | if (mask % 8 == 0 || (((u_char *)addr)[n] & m) == (((u_char *)dest)[n] & m)) | |
54 | return (1); | |
55 | } | |
56 | return (0); | |
57 | } | |
58 | ||
59 | prefix_t * | |
60 | patricia_new_prefix (struct irc_in_addr *dest, int bitlen) | |
61 | { | |
62 | prefix_t *prefix = NULL; | |
63 | ||
64 | prefix = malloc(sizeof (prefix_t)); | |
65 | memcpy (&prefix->sin, dest, 16); | |
66 | ||
67 | prefix->bitlen = (bitlen >= 0)? bitlen: 128; | |
68 | prefix->ref_count = 1; | |
69 | return prefix; | |
70 | } | |
71 | ||
72 | prefix_t * | |
73 | patricia_ref_prefix (prefix_t * prefix) | |
74 | { | |
75 | if (prefix == NULL) | |
76 | return (NULL); | |
77 | if (prefix->ref_count == 0) { | |
78 | /* make a copy in case of a static prefix */ | |
79 | return (patricia_new_prefix (&prefix->sin, prefix->bitlen)); | |
80 | } | |
81 | prefix->ref_count++; | |
82 | /* fprintf(stderr, "[A %s, %d]\n", prefix_toa (prefix), prefix->ref_count); */ | |
83 | return (prefix); | |
84 | } | |
85 | ||
86 | void | |
87 | patricia_deref_prefix (prefix_t * prefix) | |
88 | { | |
89 | if (prefix == NULL) | |
90 | return; | |
91 | /* for secure programming, raise an assert. no static prefix can call this */ | |
92 | assert (prefix->ref_count > 0); | |
93 | ||
94 | prefix->ref_count--; | |
95 | assert (prefix->ref_count >= 0); | |
96 | if (prefix->ref_count <= 0) { | |
97 | free(prefix); | |
98 | return; | |
99 | } | |
100 | } | |
101 | ||
102 | /* } */ | |
103 | ||
104 | /* #define PATRICIA_DEBUG 1 */ | |
105 | ||
106 | /* these routines support continuous mask only */ | |
107 | ||
108 | patricia_tree_t * | |
109 | patricia_new_tree (int maxbits) | |
110 | { | |
111 | patricia_tree_t *patricia = calloc(1, sizeof *patricia); | |
112 | ||
113 | patricia->maxbits = maxbits; | |
114 | patricia->head = NULL; | |
115 | patricia->num_active_node = 0; | |
116 | assert (maxbits <= PATRICIA_MAXBITS); /* XXX */ | |
117 | return (patricia); | |
118 | } | |
119 | ||
120 | ||
121 | void | |
122 | patricia_clear_tree (patricia_tree_t *patricia, void_fn_t func) | |
123 | { | |
124 | assert (patricia); | |
125 | if (patricia->head) { | |
126 | ||
127 | patricia_node_t *Xstack[PATRICIA_MAXBITS+1]; | |
128 | patricia_node_t **Xsp = Xstack; | |
129 | patricia_node_t *Xrn = patricia->head; | |
130 | ||
131 | while (Xrn) { | |
132 | patricia_node_t *l = Xrn->l; | |
133 | patricia_node_t *r = Xrn->r; | |
134 | ||
135 | if (Xrn->prefix) { | |
136 | if (Xrn->slots && func) | |
137 | func(Xrn->slots); | |
138 | patricia_deref_prefix (Xrn->prefix); | |
139 | } | |
140 | free(Xrn); | |
141 | patricia->num_active_node--; | |
142 | ||
143 | if (l) { | |
144 | if (r) { | |
145 | *Xsp++ = r; | |
146 | } | |
147 | Xrn = l; | |
148 | } else if (r) { | |
149 | Xrn = r; | |
150 | } else if (Xsp != Xstack) { | |
151 | Xrn = *(--Xsp); | |
152 | } else { | |
153 | Xrn = (patricia_node_t *) 0; | |
154 | } | |
155 | } | |
156 | } | |
157 | assert (patricia->num_active_node == 0); | |
158 | /* free(patricia); */ | |
159 | } | |
160 | ||
161 | ||
162 | void | |
163 | patricia_destroy_tree (patricia_tree_t *patricia, void_fn_t func) | |
164 | { | |
165 | patricia_clear_tree (patricia, func); | |
166 | free(patricia); | |
167 | } | |
168 | ||
169 | ||
170 | /* | |
171 | * if func is supplied, it will be called as func(node->prefix) | |
172 | */ | |
173 | ||
174 | void | |
175 | patricia_process (patricia_tree_t *patricia, void_fn_t func) | |
176 | { | |
177 | patricia_node_t *node; | |
178 | assert (func); | |
179 | ||
180 | PATRICIA_WALK (patricia->head, node) { | |
181 | func (node->prefix); | |
182 | } PATRICIA_WALK_END; | |
183 | } | |
184 | ||
185 | size_t | |
186 | patricia_walk_inorder(patricia_node_t *node, void_fn_t func) | |
187 | { | |
188 | size_t n = 0; | |
189 | assert(func); | |
190 | ||
191 | if (node->l) { | |
192 | n += patricia_walk_inorder(node->l, func); | |
193 | } | |
194 | ||
195 | if (node->prefix) { | |
196 | func(node->prefix); | |
197 | n++; | |
198 | } | |
199 | ||
200 | if (node->r) { | |
201 | n += patricia_walk_inorder(node->r, func); | |
202 | } | |
203 | ||
204 | return n; | |
205 | } | |
206 | ||
207 | ||
208 | patricia_node_t * | |
209 | patricia_search_exact (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen) | |
210 | { | |
211 | patricia_node_t *node; | |
212 | u_char *addr; | |
213 | ||
214 | assert (patricia); | |
215 | assert (sin); | |
216 | assert (bitlen <= patricia->maxbits); | |
217 | ||
218 | if (patricia->head == NULL) | |
219 | return (NULL); | |
220 | ||
221 | node = patricia->head; | |
222 | addr = (u_char *)sin; | |
223 | ||
224 | while (node->bit < bitlen) { | |
225 | if (BIT_TEST (addr[node->bit >> 3], 0x80 >> (node->bit & 0x07))) | |
226 | node = node->r; | |
227 | else | |
228 | node = node->l; | |
229 | ||
230 | if (node == NULL) | |
231 | return (NULL); | |
232 | } | |
233 | ||
234 | if (node->bit > bitlen || node->prefix == NULL) | |
235 | return (NULL); | |
236 | assert (node->bit == bitlen); | |
237 | assert (node->bit == node->prefix->bitlen); | |
238 | if (comp_with_mask (prefix_tochar (node->prefix), addr, bitlen)) { | |
239 | return (node); | |
240 | } | |
241 | return (NULL); | |
242 | } | |
243 | ||
244 | ||
245 | /* if inclusive != 0, "best" may be the given prefix itself */ | |
246 | patricia_node_t * | |
247 | patricia_search_best2 (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen, int inclusive) | |
248 | { | |
249 | patricia_node_t *node; | |
250 | patricia_node_t *stack[PATRICIA_MAXBITS + 1]; | |
251 | u_char *addr; | |
252 | int cnt = 0; | |
253 | ||
254 | assert (patricia); | |
255 | assert (sin); | |
256 | assert (bitlen <= patricia->maxbits); | |
257 | ||
258 | if (patricia->head == NULL) | |
259 | return (NULL); | |
260 | ||
261 | node = patricia->head; | |
262 | addr = (u_char *)sin; | |
263 | ||
264 | while (node->bit < bitlen) { | |
265 | ||
266 | if (node->prefix) { | |
267 | stack[cnt++] = node; | |
268 | } | |
269 | ||
270 | if (BIT_TEST (addr[node->bit >> 3], 0x80 >> (node->bit & 0x07))) { | |
271 | node = node->r; | |
272 | } | |
273 | else { | |
274 | node = node->l; | |
275 | } | |
276 | ||
277 | if (node == NULL) | |
278 | break; | |
279 | } | |
280 | ||
281 | if (inclusive && node && node->prefix) | |
282 | stack[cnt++] = node; | |
283 | ||
284 | if (cnt <= 0) | |
285 | return (NULL); | |
286 | ||
287 | while (--cnt >= 0) { | |
288 | node = stack[cnt]; | |
289 | if (comp_with_mask (prefix_tochar (node->prefix), | |
290 | addr, | |
291 | node->prefix->bitlen)) { | |
292 | return (node); | |
293 | } | |
294 | } | |
295 | return (NULL); | |
296 | } | |
297 | ||
298 | ||
299 | patricia_node_t * | |
300 | patricia_search_best (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen) | |
301 | { | |
302 | return (patricia_search_best2 (patricia, sin, bitlen, 1)); | |
303 | } | |
304 | ||
305 | ||
306 | patricia_node_t * | |
307 | patricia_lookup (patricia_tree_t *patricia, prefix_t *prefix) | |
308 | { | |
309 | patricia_node_t *node, *new_node, *parent, *glue; | |
310 | u_char *addr, *test_addr; | |
311 | u_int bitlen, check_bit, differ_bit; | |
312 | int i, j, r; | |
313 | ||
314 | assert (patricia); | |
315 | assert (prefix); | |
316 | assert (prefix->bitlen <= patricia->maxbits); | |
317 | ||
318 | /* if new trie, create the first node */ | |
319 | if (patricia->head == NULL) { | |
320 | node = malloc(sizeof *node); | |
321 | node->bit = prefix->bitlen; | |
322 | node->prefix = patricia_ref_prefix (prefix); | |
323 | node->parent = NULL; | |
324 | node->l = node->r = NULL; | |
325 | patricia->head = node; | |
326 | patricia->num_active_node++; | |
327 | return (node); | |
328 | } | |
329 | ||
330 | addr = prefix_touchar (prefix); | |
331 | bitlen = prefix->bitlen; | |
332 | node = patricia->head; | |
333 | ||
334 | /* while ( bitlength of tree node < bitlength of node we're searching for || the node has no prefix */ | |
335 | while (node->bit < bitlen || node->prefix == NULL) { | |
336 | /* check that we're not at the lowest leaf i.e. node->bit is less than max bits */ | |
337 | if (node->bit < patricia->maxbits && | |
338 | (addr[node->bit >> 3]) & (0x80 >> (node->bit & 0x07))) { | |
339 | if (node->r == NULL) | |
340 | break; | |
341 | node = node->r; | |
342 | } | |
343 | else { | |
344 | if (node->l == NULL) | |
345 | break; | |
346 | node = node->l; | |
347 | } | |
348 | ||
349 | assert (node); | |
350 | } | |
351 | ||
352 | assert (node->prefix); | |
353 | ||
354 | test_addr = prefix_touchar (node->prefix); | |
355 | /* find the first bit different */ | |
356 | check_bit = (node->bit < bitlen)? node->bit: bitlen; | |
357 | differ_bit = 0; | |
358 | for (i = 0; i*8 < check_bit; i++) { | |
359 | if ((r = (addr[i] ^ test_addr[i])) == 0) { | |
360 | differ_bit = (i + 1) * 8; | |
361 | continue; | |
362 | } | |
363 | /* I know the better way, but for now */ | |
364 | for (j = 0; j < 8; j++) { | |
365 | if ((r) & ((0x80 >> j))) | |
366 | break; | |
367 | } | |
368 | /* must be found */ | |
369 | assert (j < 8); | |
370 | differ_bit = i * 8 + j; | |
371 | break; | |
372 | } | |
373 | if (differ_bit > check_bit) | |
374 | differ_bit = check_bit; | |
375 | ||
376 | ||
377 | parent = node->parent; | |
378 | while (parent && parent->bit >= differ_bit) { | |
379 | node = parent; | |
380 | parent = node->parent; | |
381 | } | |
382 | ||
383 | if (differ_bit == bitlen && node->bit == bitlen) { | |
384 | if (node->prefix) { | |
385 | return (node); | |
386 | } | |
387 | node->prefix = patricia_ref_prefix (prefix); | |
388 | return (node); | |
389 | } | |
390 | ||
391 | new_node = malloc(sizeof *new_node); | |
392 | new_node->bit = prefix->bitlen; | |
393 | new_node->prefix = patricia_ref_prefix (prefix); | |
394 | new_node->parent = NULL; | |
395 | new_node->l = new_node->r = NULL; | |
396 | patricia->num_active_node++; | |
397 | ||
398 | if (node->bit == differ_bit) { | |
399 | new_node->parent = node; | |
400 | if (node->bit < patricia->maxbits && | |
401 | (addr[node->bit >> 3]) & (0x80 >> (node->bit & 0x07))) { | |
402 | assert (node->r == NULL); | |
403 | node->r = new_node; | |
404 | } | |
405 | else { | |
406 | assert (node->l == NULL); | |
407 | node->l = new_node; | |
408 | } | |
409 | return (new_node); | |
410 | } | |
411 | ||
412 | if (bitlen == differ_bit) { | |
413 | if (bitlen < patricia->maxbits && | |
414 | (test_addr[bitlen >> 3]) & (0x80 >> (bitlen & 0x07))) { | |
415 | new_node->r = node; | |
416 | } | |
417 | else { | |
418 | new_node->l = node; | |
419 | } | |
420 | new_node->parent = node->parent; | |
421 | if (node->parent == NULL) { | |
422 | assert (patricia->head == node); | |
423 | patricia->head = new_node; | |
424 | } | |
425 | else if (node->parent->r == node) { | |
426 | node->parent->r = new_node; | |
427 | } | |
428 | else { | |
429 | node->parent->l = new_node; | |
430 | } | |
431 | node->parent = new_node; | |
432 | } | |
433 | else { | |
434 | glue = malloc(sizeof *glue); | |
435 | glue->bit = differ_bit; | |
436 | glue->prefix = NULL; | |
437 | glue->parent = node->parent; | |
438 | patricia->num_active_node++; | |
439 | if (differ_bit < patricia->maxbits && | |
440 | (addr[differ_bit >> 3]) & (0x80 >> (differ_bit & 0x07))) { | |
441 | glue->r = new_node; | |
442 | glue->l = node; | |
443 | } | |
444 | else { | |
445 | glue->r = node; | |
446 | glue->l = new_node; | |
447 | } | |
448 | new_node->parent = glue; | |
449 | ||
450 | if (node->parent == NULL) { | |
451 | assert (patricia->head == node); | |
452 | patricia->head = glue; | |
453 | } | |
454 | else if (node->parent->r == node) { | |
455 | node->parent->r = glue; | |
456 | } | |
457 | else { | |
458 | node->parent->l = glue; | |
459 | } | |
460 | node->parent = glue; | |
461 | } | |
462 | return (new_node); | |
463 | } | |
464 | ||
465 | void | |
466 | patricia_remove (patricia_tree_t *patricia, patricia_node_t *node) | |
467 | { | |
468 | patricia_node_t *parent, *child; | |
469 | ||
470 | assert (patricia); | |
471 | assert (node); | |
472 | ||
473 | if (node->r && node->l) { | |
474 | /* this might be a placeholder node -- have to check and make sure | |
475 | * there is a prefix aossciated with it ! */ | |
476 | if (node->prefix != NULL) | |
477 | patricia_deref_prefix (node->prefix); | |
478 | node->prefix = NULL; | |
479 | return; | |
480 | } | |
481 | ||
482 | if (node->r == NULL && node->l == NULL) { | |
483 | parent = node->parent; | |
484 | patricia_deref_prefix (node->prefix); | |
485 | free(node); | |
486 | patricia->num_active_node--; | |
487 | ||
488 | if (parent == NULL) { | |
489 | assert (patricia->head == node); | |
490 | patricia->head = NULL; | |
491 | return; | |
492 | } | |
493 | ||
494 | if (parent->r == node) { | |
495 | parent->r = NULL; | |
496 | child = parent->l; | |
497 | } | |
498 | else { | |
499 | assert (parent->l == node); | |
500 | parent->l = NULL; | |
501 | child = parent->r; | |
502 | } | |
503 | ||
504 | if (parent->prefix) | |
505 | return; | |
506 | ||
507 | /* we need to remove parent too */ | |
508 | ||
509 | if (parent->parent == NULL) { | |
510 | assert (patricia->head == parent); | |
511 | patricia->head = child; | |
512 | } | |
513 | else if (parent->parent->r == parent) { | |
514 | parent->parent->r = child; | |
515 | } | |
516 | else { | |
517 | assert (parent->parent->l == parent); | |
518 | parent->parent->l = child; | |
519 | } | |
520 | child->parent = parent->parent; | |
521 | free(parent); | |
522 | patricia->num_active_node--; | |
523 | return; | |
524 | } | |
525 | ||
526 | if (node->r) { | |
527 | child = node->r; | |
528 | } | |
529 | else { | |
530 | assert (node->l); | |
531 | child = node->l; | |
532 | } | |
533 | parent = node->parent; | |
534 | child->parent = parent; | |
535 | ||
536 | patricia_deref_prefix (node->prefix); | |
537 | free(node); | |
538 | patricia->num_active_node--; | |
539 | ||
540 | if (parent == NULL) { | |
541 | assert (patricia->head == node); | |
542 | patricia->head = child; | |
543 | return; | |
544 | } | |
545 | ||
546 | if (parent->r == node) { | |
547 | parent->r = child; | |
548 | } | |
549 | else { | |
550 | assert (parent->l == node); | |
551 | parent->l = child; | |
552 | } | |
553 | } | |
554 | ||
555 | /* } */ | |
556 | ||
557 | patricia_node_t * | |
558 | refnode(patricia_tree_t *tree, struct irc_in_addr *sin, int bitlen) { | |
559 | patricia_node_t *node; | |
560 | prefix_t *prefix; | |
561 | ||
562 | node = patricia_search_exact(tree, sin, PATRICIA_MAXBITS); | |
563 | ||
564 | if (node == NULL) { | |
565 | prefix = patricia_new_prefix(sin, bitlen); | |
566 | node = patricia_lookup(tree, prefix); | |
567 | node->slots = (void **)malloc(PATRICIA_MAXSLOTS * sizeof(void *)); | |
568 | memset(node->slots, 0, PATRICIA_MAXSLOTS * sizeof(void *)); | |
569 | patricia_deref_prefix(prefix); | |
570 | } else if (node->prefix) { | |
571 | patricia_ref_prefix(node->prefix); | |
572 | } | |
573 | ||
574 | return node; | |
575 | } | |
576 | ||
577 | void | |
578 | derefnode(patricia_tree_t *tree, patricia_node_t *node) { | |
579 | if (!node || !node->prefix) | |
580 | return; | |
581 | ||
582 | if (node->prefix->ref_count == 1) { | |
583 | free(node->slots); | |
584 | patricia_remove(tree, node); | |
585 | } else | |
586 | patricia_deref_prefix(node->prefix); | |
587 | } |