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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 | ||
6f8dfee9 | 15 | char patricia_copyright[] = |
526e7c1d P |
16 | "This product includes software developed by the University of Michigan, Merit" |
17 | "Network, Inc., and their contributors."; | |
18 | ||
526e7c1d P |
19 | #include <assert.h> /* assert */ |
20 | #include <ctype.h> /* isdigit */ | |
21 | #include <errno.h> /* errno */ | |
22 | #include <math.h> /* sin */ | |
23 | #include <stddef.h> /* NULL */ | |
24 | #include <stdio.h> /* sprintf, fprintf, stderr */ | |
25 | #include <stdlib.h> /* free, atol, calloc */ | |
26 | #include <string.h> /* memcpy, strchr, strlen */ | |
27 | ||
28 | #include "patricia.h" | |
29 | ||
526e7c1d P |
30 | /* prefix_tochar |
31 | * convert prefix information to bytes | |
32 | */ | |
33 | u_char * | |
34 | prefix_tochar (prefix_t * prefix) | |
35 | { | |
36 | if (prefix == NULL) | |
37 | return (NULL); | |
38 | ||
39 | return ((u_char *) & prefix->sin); | |
40 | } | |
41 | ||
42 | int | |
43 | comp_with_mask (void *addr, void *dest, u_int mask) | |
44 | { | |
45 | ||
46 | if ( /* mask/8 == 0 || */ memcmp (addr, dest, mask / 8) == 0) { | |
47 | int n = mask / 8; | |
48 | int m = ((-1) << (8 - (mask % 8))); | |
49 | ||
50 | if (mask % 8 == 0 || (((u_char *)addr)[n] & m) == (((u_char *)dest)[n] & m)) | |
51 | return (1); | |
52 | } | |
53 | return (0); | |
54 | } | |
55 | ||
56 | prefix_t * | |
57 | patricia_new_prefix (struct irc_in_addr *dest, int bitlen) | |
58 | { | |
59 | prefix_t *prefix = NULL; | |
60 | ||
61 | prefix = malloc(sizeof (prefix_t)); | |
62 | memcpy (&prefix->sin, dest, 16); | |
63 | ||
64 | prefix->bitlen = (bitlen >= 0)? bitlen: 128; | |
65 | prefix->ref_count = 1; | |
66 | return prefix; | |
67 | } | |
68 | ||
69 | prefix_t * | |
70 | patricia_ref_prefix (prefix_t * prefix) | |
71 | { | |
72 | if (prefix == NULL) | |
73 | return (NULL); | |
74 | if (prefix->ref_count == 0) { | |
75 | /* make a copy in case of a static prefix */ | |
76 | return (patricia_new_prefix (&prefix->sin, prefix->bitlen)); | |
77 | } | |
78 | prefix->ref_count++; | |
526e7c1d P |
79 | return (prefix); |
80 | } | |
81 | ||
82 | void | |
83 | patricia_deref_prefix (prefix_t * prefix) | |
84 | { | |
85 | if (prefix == NULL) | |
86 | return; | |
87 | /* for secure programming, raise an assert. no static prefix can call this */ | |
88 | assert (prefix->ref_count > 0); | |
89 | ||
90 | prefix->ref_count--; | |
526e7c1d P |
91 | if (prefix->ref_count <= 0) { |
92 | free(prefix); | |
93 | return; | |
94 | } | |
95 | } | |
96 | ||
526e7c1d P |
97 | /* these routines support continuous mask only */ |
98 | ||
99 | patricia_tree_t * | |
100 | patricia_new_tree (int maxbits) | |
101 | { | |
102 | patricia_tree_t *patricia = calloc(1, sizeof *patricia); | |
103 | ||
104 | patricia->maxbits = maxbits; | |
105 | patricia->head = NULL; | |
106 | patricia->num_active_node = 0; | |
107 | assert (maxbits <= PATRICIA_MAXBITS); /* XXX */ | |
108 | return (patricia); | |
109 | } | |
110 | ||
111 | ||
112 | void | |
113 | patricia_clear_tree (patricia_tree_t *patricia, void_fn_t func) | |
114 | { | |
115 | assert (patricia); | |
116 | if (patricia->head) { | |
117 | ||
118 | patricia_node_t *Xstack[PATRICIA_MAXBITS+1]; | |
119 | patricia_node_t **Xsp = Xstack; | |
120 | patricia_node_t *Xrn = patricia->head; | |
121 | ||
122 | while (Xrn) { | |
123 | patricia_node_t *l = Xrn->l; | |
124 | patricia_node_t *r = Xrn->r; | |
125 | ||
126 | if (Xrn->prefix) { | |
a8ba1373 P |
127 | if (Xrn->exts && func) |
128 | func(Xrn->exts); | |
526e7c1d P |
129 | patricia_deref_prefix (Xrn->prefix); |
130 | } | |
131 | free(Xrn); | |
132 | patricia->num_active_node--; | |
133 | ||
134 | if (l) { | |
135 | if (r) { | |
136 | *Xsp++ = r; | |
137 | } | |
138 | Xrn = l; | |
139 | } else if (r) { | |
140 | Xrn = r; | |
141 | } else if (Xsp != Xstack) { | |
142 | Xrn = *(--Xsp); | |
143 | } else { | |
144 | Xrn = (patricia_node_t *) 0; | |
145 | } | |
146 | } | |
147 | } | |
148 | assert (patricia->num_active_node == 0); | |
149 | /* free(patricia); */ | |
150 | } | |
151 | ||
526e7c1d P |
152 | void |
153 | patricia_destroy_tree (patricia_tree_t *patricia, void_fn_t func) | |
154 | { | |
155 | patricia_clear_tree (patricia, func); | |
156 | free(patricia); | |
157 | } | |
158 | ||
159 | ||
160 | /* | |
161 | * if func is supplied, it will be called as func(node->prefix) | |
162 | */ | |
163 | ||
164 | void | |
165 | patricia_process (patricia_tree_t *patricia, void_fn_t func) | |
166 | { | |
167 | patricia_node_t *node; | |
168 | assert (func); | |
169 | ||
170 | PATRICIA_WALK (patricia->head, node) { | |
171 | func (node->prefix); | |
172 | } PATRICIA_WALK_END; | |
173 | } | |
174 | ||
175 | size_t | |
176 | patricia_walk_inorder(patricia_node_t *node, void_fn_t func) | |
177 | { | |
178 | size_t n = 0; | |
179 | assert(func); | |
180 | ||
181 | if (node->l) { | |
182 | n += patricia_walk_inorder(node->l, func); | |
183 | } | |
184 | ||
185 | if (node->prefix) { | |
186 | func(node->prefix); | |
187 | n++; | |
188 | } | |
189 | ||
190 | if (node->r) { | |
191 | n += patricia_walk_inorder(node->r, func); | |
192 | } | |
193 | ||
194 | return n; | |
195 | } | |
196 | ||
197 | ||
198 | patricia_node_t * | |
199 | patricia_search_exact (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen) | |
200 | { | |
201 | patricia_node_t *node; | |
202 | u_char *addr; | |
203 | ||
204 | assert (patricia); | |
205 | assert (sin); | |
206 | assert (bitlen <= patricia->maxbits); | |
207 | ||
208 | if (patricia->head == NULL) | |
209 | return (NULL); | |
210 | ||
211 | node = patricia->head; | |
212 | addr = (u_char *)sin; | |
213 | ||
214 | while (node->bit < bitlen) { | |
215 | if (BIT_TEST (addr[node->bit >> 3], 0x80 >> (node->bit & 0x07))) | |
216 | node = node->r; | |
217 | else | |
218 | node = node->l; | |
219 | ||
220 | if (node == NULL) | |
221 | return (NULL); | |
222 | } | |
223 | ||
224 | if (node->bit > bitlen || node->prefix == NULL) | |
225 | return (NULL); | |
226 | assert (node->bit == bitlen); | |
227 | assert (node->bit == node->prefix->bitlen); | |
228 | if (comp_with_mask (prefix_tochar (node->prefix), addr, bitlen)) { | |
229 | return (node); | |
230 | } | |
231 | return (NULL); | |
232 | } | |
233 | ||
234 | ||
235 | /* if inclusive != 0, "best" may be the given prefix itself */ | |
236 | patricia_node_t * | |
237 | patricia_search_best2 (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen, int inclusive) | |
238 | { | |
239 | patricia_node_t *node; | |
240 | patricia_node_t *stack[PATRICIA_MAXBITS + 1]; | |
241 | u_char *addr; | |
242 | int cnt = 0; | |
243 | ||
244 | assert (patricia); | |
245 | assert (sin); | |
246 | assert (bitlen <= patricia->maxbits); | |
247 | ||
248 | if (patricia->head == NULL) | |
249 | return (NULL); | |
250 | ||
251 | node = patricia->head; | |
252 | addr = (u_char *)sin; | |
253 | ||
254 | while (node->bit < bitlen) { | |
255 | ||
256 | if (node->prefix) { | |
257 | stack[cnt++] = node; | |
258 | } | |
259 | ||
260 | if (BIT_TEST (addr[node->bit >> 3], 0x80 >> (node->bit & 0x07))) { | |
261 | node = node->r; | |
262 | } | |
263 | else { | |
264 | node = node->l; | |
265 | } | |
266 | ||
267 | if (node == NULL) | |
268 | break; | |
269 | } | |
270 | ||
271 | if (inclusive && node && node->prefix) | |
272 | stack[cnt++] = node; | |
273 | ||
274 | if (cnt <= 0) | |
275 | return (NULL); | |
276 | ||
277 | while (--cnt >= 0) { | |
278 | node = stack[cnt]; | |
279 | if (comp_with_mask (prefix_tochar (node->prefix), | |
280 | addr, | |
281 | node->prefix->bitlen)) { | |
282 | return (node); | |
283 | } | |
284 | } | |
285 | return (NULL); | |
286 | } | |
287 | ||
288 | ||
289 | patricia_node_t * | |
290 | patricia_search_best (patricia_tree_t *patricia, struct irc_in_addr *sin, unsigned char bitlen) | |
291 | { | |
292 | return (patricia_search_best2 (patricia, sin, bitlen, 1)); | |
293 | } | |
294 | ||
295 | ||
296 | patricia_node_t * | |
297 | patricia_lookup (patricia_tree_t *patricia, prefix_t *prefix) | |
298 | { | |
299 | patricia_node_t *node, *new_node, *parent, *glue; | |
300 | u_char *addr, *test_addr; | |
301 | u_int bitlen, check_bit, differ_bit; | |
302 | int i, j, r; | |
303 | ||
304 | assert (patricia); | |
305 | assert (prefix); | |
306 | assert (prefix->bitlen <= patricia->maxbits); | |
307 | ||
308 | /* if new trie, create the first node */ | |
309 | if (patricia->head == NULL) { | |
310 | node = malloc(sizeof *node); | |
a8ba1373 | 311 | memset(node->exts, 0, PATRICIA_MAXSLOTS * sizeof(void *)); |
526e7c1d P |
312 | node->bit = prefix->bitlen; |
313 | node->prefix = patricia_ref_prefix (prefix); | |
314 | node->parent = NULL; | |
315 | node->l = node->r = NULL; | |
24d73e9c | 316 | node->usercount = 0; |
526e7c1d P |
317 | patricia->head = node; |
318 | patricia->num_active_node++; | |
319 | return (node); | |
320 | } | |
321 | ||
322 | addr = prefix_touchar (prefix); | |
323 | bitlen = prefix->bitlen; | |
324 | node = patricia->head; | |
325 | ||
326 | /* while ( bitlength of tree node < bitlength of node we're searching for || the node has no prefix */ | |
327 | while (node->bit < bitlen || node->prefix == NULL) { | |
328 | /* check that we're not at the lowest leaf i.e. node->bit is less than max bits */ | |
329 | if (node->bit < patricia->maxbits && | |
330 | (addr[node->bit >> 3]) & (0x80 >> (node->bit & 0x07))) { | |
331 | if (node->r == NULL) | |
332 | break; | |
333 | node = node->r; | |
334 | } | |
335 | else { | |
336 | if (node->l == NULL) | |
337 | break; | |
338 | node = node->l; | |
339 | } | |
340 | ||
341 | assert (node); | |
342 | } | |
343 | ||
344 | assert (node->prefix); | |
345 | ||
346 | test_addr = prefix_touchar (node->prefix); | |
347 | /* find the first bit different */ | |
348 | check_bit = (node->bit < bitlen)? node->bit: bitlen; | |
349 | differ_bit = 0; | |
350 | for (i = 0; i*8 < check_bit; i++) { | |
351 | if ((r = (addr[i] ^ test_addr[i])) == 0) { | |
352 | differ_bit = (i + 1) * 8; | |
353 | continue; | |
354 | } | |
355 | /* I know the better way, but for now */ | |
356 | for (j = 0; j < 8; j++) { | |
357 | if ((r) & ((0x80 >> j))) | |
358 | break; | |
359 | } | |
360 | /* must be found */ | |
361 | assert (j < 8); | |
362 | differ_bit = i * 8 + j; | |
363 | break; | |
364 | } | |
365 | if (differ_bit > check_bit) | |
366 | differ_bit = check_bit; | |
367 | ||
368 | ||
369 | parent = node->parent; | |
370 | while (parent && parent->bit >= differ_bit) { | |
371 | node = parent; | |
372 | parent = node->parent; | |
373 | } | |
374 | ||
375 | if (differ_bit == bitlen && node->bit == bitlen) { | |
376 | if (node->prefix) { | |
377 | return (node); | |
378 | } | |
379 | node->prefix = patricia_ref_prefix (prefix); | |
380 | return (node); | |
381 | } | |
382 | ||
383 | new_node = malloc(sizeof *new_node); | |
a8ba1373 | 384 | memset(new_node->exts, 0, PATRICIA_MAXSLOTS * sizeof(void *)); |
526e7c1d P |
385 | new_node->bit = prefix->bitlen; |
386 | new_node->prefix = patricia_ref_prefix (prefix); | |
387 | new_node->parent = NULL; | |
388 | new_node->l = new_node->r = NULL; | |
24d73e9c | 389 | new_node->usercount = 0; |
526e7c1d P |
390 | patricia->num_active_node++; |
391 | ||
392 | if (node->bit == differ_bit) { | |
393 | new_node->parent = node; | |
394 | if (node->bit < patricia->maxbits && | |
395 | (addr[node->bit >> 3]) & (0x80 >> (node->bit & 0x07))) { | |
396 | assert (node->r == NULL); | |
397 | node->r = new_node; | |
398 | } | |
399 | else { | |
400 | assert (node->l == NULL); | |
401 | node->l = new_node; | |
402 | } | |
403 | return (new_node); | |
404 | } | |
405 | ||
406 | if (bitlen == differ_bit) { | |
407 | if (bitlen < patricia->maxbits && | |
408 | (test_addr[bitlen >> 3]) & (0x80 >> (bitlen & 0x07))) { | |
409 | new_node->r = node; | |
410 | } | |
411 | else { | |
412 | new_node->l = node; | |
413 | } | |
414 | new_node->parent = node->parent; | |
415 | if (node->parent == NULL) { | |
416 | assert (patricia->head == node); | |
417 | patricia->head = new_node; | |
418 | } | |
419 | else if (node->parent->r == node) { | |
420 | node->parent->r = new_node; | |
421 | } | |
422 | else { | |
423 | node->parent->l = new_node; | |
424 | } | |
425 | node->parent = new_node; | |
426 | } | |
427 | else { | |
428 | glue = malloc(sizeof *glue); | |
a8ba1373 | 429 | memset(glue->exts, 0, PATRICIA_MAXSLOTS * sizeof(void *)); |
526e7c1d P |
430 | glue->bit = differ_bit; |
431 | glue->prefix = NULL; | |
432 | glue->parent = node->parent; | |
24d73e9c | 433 | glue->usercount = 0; |
526e7c1d P |
434 | patricia->num_active_node++; |
435 | if (differ_bit < patricia->maxbits && | |
436 | (addr[differ_bit >> 3]) & (0x80 >> (differ_bit & 0x07))) { | |
437 | glue->r = new_node; | |
438 | glue->l = node; | |
439 | } | |
440 | else { | |
441 | glue->r = node; | |
442 | glue->l = new_node; | |
443 | } | |
444 | new_node->parent = glue; | |
445 | ||
446 | if (node->parent == NULL) { | |
447 | assert (patricia->head == node); | |
448 | patricia->head = glue; | |
449 | } | |
450 | else if (node->parent->r == node) { | |
451 | node->parent->r = glue; | |
452 | } | |
453 | else { | |
454 | node->parent->l = glue; | |
455 | } | |
456 | node->parent = glue; | |
457 | } | |
458 | return (new_node); | |
459 | } | |
460 | ||
461 | void | |
462 | patricia_remove (patricia_tree_t *patricia, patricia_node_t *node) | |
463 | { | |
464 | patricia_node_t *parent, *child; | |
465 | ||
466 | assert (patricia); | |
467 | assert (node); | |
468 | ||
469 | if (node->r && node->l) { | |
470 | /* this might be a placeholder node -- have to check and make sure | |
471 | * there is a prefix aossciated with it ! */ | |
472 | if (node->prefix != NULL) | |
473 | patricia_deref_prefix (node->prefix); | |
474 | node->prefix = NULL; | |
475 | return; | |
476 | } | |
477 | ||
478 | if (node->r == NULL && node->l == NULL) { | |
479 | parent = node->parent; | |
480 | patricia_deref_prefix (node->prefix); | |
481 | free(node); | |
482 | patricia->num_active_node--; | |
483 | ||
484 | if (parent == NULL) { | |
485 | assert (patricia->head == node); | |
486 | patricia->head = NULL; | |
487 | return; | |
488 | } | |
489 | ||
490 | if (parent->r == node) { | |
491 | parent->r = NULL; | |
492 | child = parent->l; | |
493 | } | |
494 | else { | |
495 | assert (parent->l == node); | |
496 | parent->l = NULL; | |
497 | child = parent->r; | |
498 | } | |
499 | ||
500 | if (parent->prefix) | |
501 | return; | |
502 | ||
503 | /* we need to remove parent too */ | |
504 | ||
505 | if (parent->parent == NULL) { | |
506 | assert (patricia->head == parent); | |
507 | patricia->head = child; | |
508 | } | |
509 | else if (parent->parent->r == parent) { | |
510 | parent->parent->r = child; | |
511 | } | |
512 | else { | |
513 | assert (parent->parent->l == parent); | |
514 | parent->parent->l = child; | |
515 | } | |
516 | child->parent = parent->parent; | |
517 | free(parent); | |
518 | patricia->num_active_node--; | |
519 | return; | |
520 | } | |
521 | ||
522 | if (node->r) { | |
523 | child = node->r; | |
524 | } | |
525 | else { | |
526 | assert (node->l); | |
527 | child = node->l; | |
528 | } | |
529 | parent = node->parent; | |
530 | child->parent = parent; | |
531 | ||
532 | patricia_deref_prefix (node->prefix); | |
533 | free(node); | |
534 | patricia->num_active_node--; | |
535 | ||
536 | if (parent == NULL) { | |
537 | assert (patricia->head == node); | |
538 | patricia->head = child; | |
539 | return; | |
540 | } | |
541 | ||
542 | if (parent->r == node) { | |
543 | parent->r = child; | |
544 | } | |
545 | else { | |
546 | assert (parent->l == node); | |
547 | parent->l = child; | |
548 | } | |
549 | } | |
550 | ||
526e7c1d P |
551 | |
552 | patricia_node_t * | |
553 | refnode(patricia_tree_t *tree, struct irc_in_addr *sin, int bitlen) { | |
554 | patricia_node_t *node; | |
555 | prefix_t *prefix; | |
556 | ||
01a924c2 | 557 | node = patricia_search_exact(tree, sin, bitlen); |
526e7c1d P |
558 | |
559 | if (node == NULL) { | |
560 | prefix = patricia_new_prefix(sin, bitlen); | |
561 | node = patricia_lookup(tree, prefix); | |
526e7c1d P |
562 | patricia_deref_prefix(prefix); |
563 | } else if (node->prefix) { | |
564 | patricia_ref_prefix(node->prefix); | |
565 | } | |
566 | ||
567 | return node; | |
568 | } | |
569 | ||
570 | void | |
571 | derefnode(patricia_tree_t *tree, patricia_node_t *node) { | |
572 | if (!node || !node->prefix) | |
573 | return; | |
574 | ||
575 | if (node->prefix->ref_count == 1) { | |
526e7c1d P |
576 | patricia_remove(tree, node); |
577 | } else | |
578 | patricia_deref_prefix(node->prefix); | |
579 | } |