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1 | /* AS path management routines. | |
2 | * Copyright (C) 1996, 97, 98, 99 Kunihiro Ishiguro | |
3 | * Copyright (C) 2005 Sun Microsystems, Inc. | |
4 | * | |
5 | * This file is part of GNU Zebra. | |
6 | * | |
7 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License as published by the | |
9 | * Free Software Foundation; either version 2, or (at your option) any | |
10 | * later version. | |
11 | * | |
12 | * GNU Zebra is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License along | |
18 | * with this program; see the file COPYING; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include <zebra.h> | |
23 | ||
24 | #include "hash.h" | |
25 | #include "memory.h" | |
26 | #include "vector.h" | |
27 | #include "log.h" | |
28 | #include "stream.h" | |
29 | #include "command.h" | |
30 | #include "jhash.h" | |
31 | #include "queue.h" | |
32 | #include "filter.h" | |
33 | ||
34 | #include "bgpd/bgpd.h" | |
35 | #include "bgpd/bgp_aspath.h" | |
36 | #include "bgpd/bgp_debug.h" | |
37 | #include "bgpd/bgp_attr.h" | |
38 | ||
39 | /* Attr. Flags and Attr. Type Code. */ | |
40 | #define AS_HEADER_SIZE 2 | |
41 | ||
42 | /* Now FOUR octets are used for AS value. */ | |
43 | #define AS_VALUE_SIZE sizeof (as_t) | |
44 | /* This is the old one */ | |
45 | #define AS16_VALUE_SIZE sizeof (as16_t) | |
46 | ||
47 | /* Maximum protocol segment length value */ | |
48 | #define AS_SEGMENT_MAX 255 | |
49 | ||
50 | /* The following length and size macros relate specifically to Quagga's | |
51 | * internal representation of AS-Segments, not per se to the on-wire | |
52 | * sizes and lengths. At present (200508) they sort of match, however | |
53 | * the ONLY functions which should now about the on-wire syntax are | |
54 | * aspath_put, assegment_put and assegment_parse. | |
55 | * | |
56 | * aspath_put returns bytes written, the only definitive record of | |
57 | * size of wire-format attribute.. | |
58 | */ | |
59 | ||
60 | /* Calculated size in bytes of ASN segment data to hold N ASN's */ | |
61 | #define ASSEGMENT_DATA_SIZE(N, S) \ | |
62 | ((N) * ((S) ? AS_VALUE_SIZE : AS16_VALUE_SIZE)) | |
63 | ||
64 | /* Calculated size of segment struct to hold N ASN's */ | |
65 | #define ASSEGMENT_SIZE(N,S) (AS_HEADER_SIZE + ASSEGMENT_DATA_SIZE (N,S)) | |
66 | ||
67 | /* AS segment octet length. */ | |
68 | #define ASSEGMENT_LEN(X,S) ASSEGMENT_SIZE((X)->length,S) | |
69 | ||
70 | /* AS_SEQUENCE segments can be packed together */ | |
71 | /* Can the types of X and Y be considered for packing? */ | |
72 | #define ASSEGMENT_TYPES_PACKABLE(X, Y) \ | |
73 | (((X)->type == (Y)->type) && ((X)->type == AS_SEQUENCE)) | |
74 | /* Types and length of X,Y suitable for packing? */ | |
75 | #define ASSEGMENTS_PACKABLE(X, Y) \ | |
76 | (ASSEGMENT_TYPES_PACKABLE((X), (Y)) \ | |
77 | && (((X)->length + (Y)->length) <= AS_SEGMENT_MAX)) | |
78 | ||
79 | /* As segment header - the on-wire representation | |
80 | * NOT the internal representation! | |
81 | */ | |
82 | struct assegment_header { | |
83 | uint8_t type; | |
84 | uint8_t length; | |
85 | }; | |
86 | ||
87 | /* Hash for aspath. This is the top level structure of AS path. */ | |
88 | static struct hash *ashash; | |
89 | ||
90 | /* Stream for SNMP. See aspath_snmp_pathseg */ | |
91 | static struct stream *snmp_stream; | |
92 | ||
93 | /* Callers are required to initialize the memory */ | |
94 | static as_t *assegment_data_new(int num) | |
95 | { | |
96 | return (XMALLOC(MTYPE_AS_SEG_DATA, ASSEGMENT_DATA_SIZE(num, 1))); | |
97 | } | |
98 | ||
99 | static void assegment_data_free(as_t *asdata) | |
100 | { | |
101 | XFREE(MTYPE_AS_SEG_DATA, asdata); | |
102 | } | |
103 | ||
104 | const char *aspath_segment_type_str[] = {"as-invalid", "as-set", "as-sequence", | |
105 | "as-confed-sequence", "as-confed-set"}; | |
106 | ||
107 | /* Get a new segment. Note that 0 is an allowed length, | |
108 | * and will result in a segment with no allocated data segment. | |
109 | * the caller should immediately assign data to the segment, as the segment | |
110 | * otherwise is not generally valid | |
111 | */ | |
112 | static struct assegment *assegment_new(uint8_t type, unsigned short length) | |
113 | { | |
114 | struct assegment *new; | |
115 | ||
116 | new = XCALLOC(MTYPE_AS_SEG, sizeof(struct assegment)); | |
117 | ||
118 | if (length) | |
119 | new->as = assegment_data_new(length); | |
120 | ||
121 | new->length = length; | |
122 | new->type = type; | |
123 | ||
124 | return new; | |
125 | } | |
126 | ||
127 | static void assegment_free(struct assegment *seg) | |
128 | { | |
129 | if (!seg) | |
130 | return; | |
131 | ||
132 | if (seg->as) | |
133 | assegment_data_free(seg->as); | |
134 | memset(seg, 0xfe, sizeof(struct assegment)); | |
135 | XFREE(MTYPE_AS_SEG, seg); | |
136 | ||
137 | return; | |
138 | } | |
139 | ||
140 | /* free entire chain of segments */ | |
141 | static void assegment_free_all(struct assegment *seg) | |
142 | { | |
143 | struct assegment *prev; | |
144 | ||
145 | while (seg) { | |
146 | prev = seg; | |
147 | seg = seg->next; | |
148 | assegment_free(prev); | |
149 | } | |
150 | } | |
151 | ||
152 | /* Duplicate just the given assegment and its data */ | |
153 | static struct assegment *assegment_dup(struct assegment *seg) | |
154 | { | |
155 | struct assegment *new; | |
156 | ||
157 | new = assegment_new(seg->type, seg->length); | |
158 | memcpy(new->as, seg->as, ASSEGMENT_DATA_SIZE(new->length, 1)); | |
159 | ||
160 | return new; | |
161 | } | |
162 | ||
163 | /* Duplicate entire chain of assegments, return the head */ | |
164 | static struct assegment *assegment_dup_all(struct assegment *seg) | |
165 | { | |
166 | struct assegment *new = NULL; | |
167 | struct assegment *head = NULL; | |
168 | ||
169 | while (seg) { | |
170 | if (head) { | |
171 | new->next = assegment_dup(seg); | |
172 | new = new->next; | |
173 | } else | |
174 | head = new = assegment_dup(seg); | |
175 | ||
176 | seg = seg->next; | |
177 | } | |
178 | return head; | |
179 | } | |
180 | ||
181 | /* prepend the as number to given segment, given num of times */ | |
182 | static struct assegment *assegment_prepend_asns(struct assegment *seg, | |
183 | as_t asnum, int num) | |
184 | { | |
185 | as_t *newas; | |
186 | int i; | |
187 | ||
188 | if (!num) | |
189 | return seg; | |
190 | ||
191 | if (num >= AS_SEGMENT_MAX) | |
192 | return seg; /* we don't do huge prepends */ | |
193 | ||
194 | if ((newas = assegment_data_new(seg->length + num)) == NULL) | |
195 | return seg; | |
196 | ||
197 | for (i = 0; i < num; i++) | |
198 | newas[i] = asnum; | |
199 | ||
200 | memcpy(newas + num, seg->as, ASSEGMENT_DATA_SIZE(seg->length, 1)); | |
201 | assegment_data_free(seg->as); | |
202 | seg->as = newas; | |
203 | seg->length += num; | |
204 | ||
205 | return seg; | |
206 | } | |
207 | ||
208 | /* append given array of as numbers to the segment */ | |
209 | static struct assegment *assegment_append_asns(struct assegment *seg, | |
210 | as_t *asnos, int num) | |
211 | { | |
212 | as_t *newas; | |
213 | ||
214 | newas = XREALLOC(MTYPE_AS_SEG_DATA, seg->as, | |
215 | ASSEGMENT_DATA_SIZE(seg->length + num, 1)); | |
216 | ||
217 | seg->as = newas; | |
218 | memcpy(seg->as + seg->length, asnos, | |
219 | ASSEGMENT_DATA_SIZE(num, 1)); | |
220 | seg->length += num; | |
221 | return seg; | |
222 | } | |
223 | ||
224 | static int int_cmp(const void *p1, const void *p2) | |
225 | { | |
226 | const as_t *as1 = p1; | |
227 | const as_t *as2 = p2; | |
228 | ||
229 | return (*as1 == *as2) ? 0 : ((*as1 > *as2) ? 1 : -1); | |
230 | } | |
231 | ||
232 | /* normalise the segment. | |
233 | * In particular, merge runs of AS_SEQUENCEs into one segment | |
234 | * Internally, we do not care about the wire segment length limit, and | |
235 | * we want each distinct AS_PATHs to have the exact same internal | |
236 | * representation - eg, so that our hashing actually works.. | |
237 | */ | |
238 | static struct assegment *assegment_normalise(struct assegment *head) | |
239 | { | |
240 | struct assegment *seg = head, *pin; | |
241 | struct assegment *tmp; | |
242 | ||
243 | if (!head) | |
244 | return head; | |
245 | ||
246 | while (seg) { | |
247 | pin = seg; | |
248 | ||
249 | /* Sort values SET segments, for determinism in paths to aid | |
250 | * creation of hash values / path comparisons | |
251 | * and because it helps other lesser implementations ;) | |
252 | */ | |
253 | if (seg->type == AS_SET || seg->type == AS_CONFED_SET) { | |
254 | int tail = 0; | |
255 | int i; | |
256 | ||
257 | qsort(seg->as, seg->length, sizeof(as_t), int_cmp); | |
258 | ||
259 | /* weed out dupes */ | |
260 | for (i = 1; i < seg->length; i++) { | |
261 | if (seg->as[tail] == seg->as[i]) | |
262 | continue; | |
263 | ||
264 | tail++; | |
265 | if (tail < i) | |
266 | seg->as[tail] = seg->as[i]; | |
267 | } | |
268 | /* seg->length can be 0.. */ | |
269 | if (seg->length) | |
270 | seg->length = tail + 1; | |
271 | } | |
272 | ||
273 | /* read ahead from the current, pinned segment while the | |
274 | * segments | |
275 | * are packable/mergeable. Append all following packable | |
276 | * segments | |
277 | * to the segment we have pinned and remove these appended | |
278 | * segments. | |
279 | */ | |
280 | while (pin->next && ASSEGMENT_TYPES_PACKABLE(pin, pin->next)) { | |
281 | tmp = pin->next; | |
282 | seg = pin->next; | |
283 | ||
284 | /* append the next sequence to the pinned sequence */ | |
285 | pin = assegment_append_asns(pin, seg->as, seg->length); | |
286 | ||
287 | /* bypass the next sequence */ | |
288 | pin->next = seg->next; | |
289 | ||
290 | /* get rid of the now referenceless segment */ | |
291 | assegment_free(tmp); | |
292 | } | |
293 | ||
294 | seg = pin->next; | |
295 | } | |
296 | return head; | |
297 | } | |
298 | ||
299 | static struct aspath *aspath_new(void) | |
300 | { | |
301 | return XCALLOC(MTYPE_AS_PATH, sizeof(struct aspath)); | |
302 | } | |
303 | ||
304 | /* Free AS path structure. */ | |
305 | void aspath_free(struct aspath *aspath) | |
306 | { | |
307 | if (!aspath) | |
308 | return; | |
309 | if (aspath->segments) | |
310 | assegment_free_all(aspath->segments); | |
311 | if (aspath->str) | |
312 | XFREE(MTYPE_AS_STR, aspath->str); | |
313 | ||
314 | if (aspath->json) { | |
315 | json_object_free(aspath->json); | |
316 | aspath->json = NULL; | |
317 | } | |
318 | ||
319 | XFREE(MTYPE_AS_PATH, aspath); | |
320 | } | |
321 | ||
322 | /* Unintern aspath from AS path bucket. */ | |
323 | void aspath_unintern(struct aspath **aspath) | |
324 | { | |
325 | struct aspath *ret; | |
326 | struct aspath *asp = *aspath; | |
327 | ||
328 | if (asp->refcnt) | |
329 | asp->refcnt--; | |
330 | ||
331 | if (asp->refcnt == 0) { | |
332 | /* This aspath must exist in aspath hash table. */ | |
333 | ret = hash_release(ashash, asp); | |
334 | assert(ret != NULL); | |
335 | aspath_free(asp); | |
336 | *aspath = NULL; | |
337 | } | |
338 | } | |
339 | ||
340 | /* Return the start or end delimiters for a particular Segment type */ | |
341 | #define AS_SEG_START 0 | |
342 | #define AS_SEG_END 1 | |
343 | static char aspath_delimiter_char(uint8_t type, uint8_t which) | |
344 | { | |
345 | int i; | |
346 | struct { | |
347 | int type; | |
348 | char start; | |
349 | char end; | |
350 | } aspath_delim_char[] = {{AS_SET, '{', '}'}, | |
351 | {AS_CONFED_SET, '[', ']'}, | |
352 | {AS_CONFED_SEQUENCE, '(', ')'}, | |
353 | {0}}; | |
354 | ||
355 | for (i = 0; aspath_delim_char[i].type != 0; i++) { | |
356 | if (aspath_delim_char[i].type == type) { | |
357 | if (which == AS_SEG_START) | |
358 | return aspath_delim_char[i].start; | |
359 | else if (which == AS_SEG_END) | |
360 | return aspath_delim_char[i].end; | |
361 | } | |
362 | } | |
363 | return ' '; | |
364 | } | |
365 | ||
366 | /* countup asns from this segment and index onward */ | |
367 | static int assegment_count_asns(struct assegment *seg, int from) | |
368 | { | |
369 | int count = 0; | |
370 | while (seg) { | |
371 | if (!from) | |
372 | count += seg->length; | |
373 | else { | |
374 | count += (seg->length - from); | |
375 | from = 0; | |
376 | } | |
377 | seg = seg->next; | |
378 | } | |
379 | return count; | |
380 | } | |
381 | ||
382 | unsigned int aspath_count_confeds(struct aspath *aspath) | |
383 | { | |
384 | int count = 0; | |
385 | struct assegment *seg = aspath->segments; | |
386 | ||
387 | while (seg) { | |
388 | if (seg->type == AS_CONFED_SEQUENCE) | |
389 | count += seg->length; | |
390 | else if (seg->type == AS_CONFED_SET) | |
391 | count++; | |
392 | ||
393 | seg = seg->next; | |
394 | } | |
395 | return count; | |
396 | } | |
397 | ||
398 | unsigned int aspath_count_hops(const struct aspath *aspath) | |
399 | { | |
400 | int count = 0; | |
401 | struct assegment *seg = aspath->segments; | |
402 | ||
403 | while (seg) { | |
404 | if (seg->type == AS_SEQUENCE) | |
405 | count += seg->length; | |
406 | else if (seg->type == AS_SET) | |
407 | count++; | |
408 | ||
409 | seg = seg->next; | |
410 | } | |
411 | return count; | |
412 | } | |
413 | ||
414 | /* Estimate size aspath /might/ take if encoded into an | |
415 | * ASPATH attribute. | |
416 | * | |
417 | * This is a quick estimate, not definitive! aspath_put() | |
418 | * may return a different number!! | |
419 | */ | |
420 | unsigned int aspath_size(struct aspath *aspath) | |
421 | { | |
422 | int size = 0; | |
423 | struct assegment *seg = aspath->segments; | |
424 | ||
425 | while (seg) { | |
426 | size += ASSEGMENT_SIZE(seg->length, 1); | |
427 | seg = seg->next; | |
428 | } | |
429 | return size; | |
430 | } | |
431 | ||
432 | /* Return highest public ASN in path */ | |
433 | as_t aspath_highest(struct aspath *aspath) | |
434 | { | |
435 | struct assegment *seg = aspath->segments; | |
436 | as_t highest = 0; | |
437 | unsigned int i; | |
438 | ||
439 | while (seg) { | |
440 | for (i = 0; i < seg->length; i++) | |
441 | if (seg->as[i] > highest | |
442 | && !BGP_AS_IS_PRIVATE(seg->as[i])) | |
443 | highest = seg->as[i]; | |
444 | seg = seg->next; | |
445 | } | |
446 | return highest; | |
447 | } | |
448 | ||
449 | /* Return the left-most ASN in path */ | |
450 | as_t aspath_leftmost(struct aspath *aspath) | |
451 | { | |
452 | struct assegment *seg = aspath->segments; | |
453 | as_t leftmost = 0; | |
454 | ||
455 | if (seg && seg->length && seg->type == AS_SEQUENCE) | |
456 | leftmost = seg->as[0]; | |
457 | ||
458 | return leftmost; | |
459 | } | |
460 | ||
461 | /* Return 1 if there are any 4-byte ASes in the path */ | |
462 | unsigned int aspath_has_as4(struct aspath *aspath) | |
463 | { | |
464 | struct assegment *seg = aspath->segments; | |
465 | unsigned int i; | |
466 | ||
467 | while (seg) { | |
468 | for (i = 0; i < seg->length; i++) | |
469 | if (seg->as[i] > BGP_AS_MAX) | |
470 | return 1; | |
471 | seg = seg->next; | |
472 | } | |
473 | return 0; | |
474 | } | |
475 | ||
476 | /* Convert aspath structure to string expression. */ | |
477 | static void aspath_make_str_count(struct aspath *as, bool make_json) | |
478 | { | |
479 | struct assegment *seg; | |
480 | int str_size; | |
481 | int len = 0; | |
482 | char *str_buf; | |
483 | json_object *jaspath_segments = NULL; | |
484 | json_object *jseg = NULL; | |
485 | json_object *jseg_list = NULL; | |
486 | ||
487 | if (make_json) { | |
488 | as->json = json_object_new_object(); | |
489 | jaspath_segments = json_object_new_array(); | |
490 | } | |
491 | ||
492 | /* Empty aspath. */ | |
493 | if (!as->segments) { | |
494 | if (make_json) { | |
495 | json_object_string_add(as->json, "string", "Local"); | |
496 | json_object_object_add(as->json, "segments", | |
497 | jaspath_segments); | |
498 | json_object_int_add(as->json, "length", 0); | |
499 | } | |
500 | as->str = XMALLOC(MTYPE_AS_STR, 1); | |
501 | as->str[0] = '\0'; | |
502 | as->str_len = 0; | |
503 | return; | |
504 | } | |
505 | ||
506 | seg = as->segments; | |
507 | ||
508 | /* ASN takes 5 to 10 chars plus seperator, see below. | |
509 | * If there is one differing segment type, we need an additional | |
510 | * 2 chars for segment delimiters, and the final '\0'. | |
511 | * Hopefully this is large enough to avoid hitting the realloc | |
512 | * code below for most common sequences. | |
513 | * | |
514 | * This was changed to 10 after the well-known BGP assertion, which | |
515 | * had hit some parts of the Internet in May of 2009. | |
516 | */ | |
517 | #define ASN_STR_LEN (10 + 1) | |
518 | str_size = MAX(assegment_count_asns(seg, 0) * ASN_STR_LEN + 2 + 1, | |
519 | ASPATH_STR_DEFAULT_LEN); | |
520 | str_buf = XMALLOC(MTYPE_AS_STR, str_size); | |
521 | ||
522 | while (seg) { | |
523 | int i; | |
524 | char seperator; | |
525 | ||
526 | /* Check AS type validity. Set seperator for segment */ | |
527 | switch (seg->type) { | |
528 | case AS_SET: | |
529 | case AS_CONFED_SET: | |
530 | seperator = ','; | |
531 | break; | |
532 | case AS_SEQUENCE: | |
533 | case AS_CONFED_SEQUENCE: | |
534 | seperator = ' '; | |
535 | break; | |
536 | default: | |
537 | XFREE(MTYPE_AS_STR, str_buf); | |
538 | as->str = NULL; | |
539 | as->str_len = 0; | |
540 | json_object_free(as->json); | |
541 | as->json = NULL; | |
542 | ||
543 | return; | |
544 | } | |
545 | ||
546 | /* We might need to increase str_buf, particularly if path has | |
547 | * differing segments types, our initial guesstimate above will | |
548 | * have been wrong. Need 10 chars for ASN, a seperator each and | |
549 | * potentially two segment delimiters, plus a space between each | |
550 | * segment and trailing zero. | |
551 | * | |
552 | * This definitely didn't work with the value of 5 bytes and | |
553 | * 32-bit ASNs. | |
554 | */ | |
555 | #define SEGMENT_STR_LEN(X) (((X)->length * ASN_STR_LEN) + 2 + 1 + 1) | |
556 | if ((len + SEGMENT_STR_LEN(seg)) > str_size) { | |
557 | str_size = len + SEGMENT_STR_LEN(seg); | |
558 | str_buf = XREALLOC(MTYPE_AS_STR, str_buf, str_size); | |
559 | } | |
560 | #undef ASN_STR_LEN | |
561 | #undef SEGMENT_STR_LEN | |
562 | ||
563 | if (seg->type != AS_SEQUENCE) | |
564 | len += snprintf( | |
565 | str_buf + len, str_size - len, "%c", | |
566 | aspath_delimiter_char(seg->type, AS_SEG_START)); | |
567 | ||
568 | if (make_json) | |
569 | jseg_list = json_object_new_array(); | |
570 | ||
571 | /* write out the ASNs, with their seperators, bar the last one*/ | |
572 | for (i = 0; i < seg->length; i++) { | |
573 | if (make_json) | |
574 | json_object_array_add( | |
575 | jseg_list, | |
576 | json_object_new_int(seg->as[i])); | |
577 | ||
578 | len += snprintf(str_buf + len, str_size - len, "%u", | |
579 | seg->as[i]); | |
580 | ||
581 | if (i < (seg->length - 1)) | |
582 | len += snprintf(str_buf + len, str_size - len, | |
583 | "%c", seperator); | |
584 | } | |
585 | ||
586 | if (make_json) { | |
587 | jseg = json_object_new_object(); | |
588 | json_object_string_add( | |
589 | jseg, "type", | |
590 | aspath_segment_type_str[seg->type]); | |
591 | json_object_object_add(jseg, "list", jseg_list); | |
592 | json_object_array_add(jaspath_segments, jseg); | |
593 | } | |
594 | ||
595 | if (seg->type != AS_SEQUENCE) | |
596 | len += snprintf( | |
597 | str_buf + len, str_size - len, "%c", | |
598 | aspath_delimiter_char(seg->type, AS_SEG_END)); | |
599 | if (seg->next) | |
600 | len += snprintf(str_buf + len, str_size - len, " "); | |
601 | ||
602 | seg = seg->next; | |
603 | } | |
604 | ||
605 | assert(len < str_size); | |
606 | ||
607 | str_buf[len] = '\0'; | |
608 | as->str = str_buf; | |
609 | as->str_len = len; | |
610 | ||
611 | if (make_json) { | |
612 | json_object_string_add(as->json, "string", str_buf); | |
613 | json_object_object_add(as->json, "segments", jaspath_segments); | |
614 | json_object_int_add(as->json, "length", aspath_count_hops(as)); | |
615 | } | |
616 | ||
617 | return; | |
618 | } | |
619 | ||
620 | void aspath_str_update(struct aspath *as, bool make_json) | |
621 | { | |
622 | if (as->str) | |
623 | XFREE(MTYPE_AS_STR, as->str); | |
624 | ||
625 | if (as->json) { | |
626 | json_object_free(as->json); | |
627 | as->json = NULL; | |
628 | } | |
629 | ||
630 | aspath_make_str_count(as, make_json); | |
631 | } | |
632 | ||
633 | /* Intern allocated AS path. */ | |
634 | struct aspath *aspath_intern(struct aspath *aspath) | |
635 | { | |
636 | struct aspath *find; | |
637 | ||
638 | /* Assert this AS path structure is not interned and has the string | |
639 | representation built. */ | |
640 | assert(aspath->refcnt == 0); | |
641 | assert(aspath->str); | |
642 | ||
643 | /* Check AS path hash. */ | |
644 | find = hash_get(ashash, aspath, hash_alloc_intern); | |
645 | if (find != aspath) | |
646 | aspath_free(aspath); | |
647 | ||
648 | find->refcnt++; | |
649 | ||
650 | return find; | |
651 | } | |
652 | ||
653 | /* Duplicate aspath structure. Created same aspath structure but | |
654 | reference count and AS path string is cleared. */ | |
655 | struct aspath *aspath_dup(struct aspath *aspath) | |
656 | { | |
657 | unsigned short buflen = aspath->str_len + 1; | |
658 | struct aspath *new; | |
659 | ||
660 | new = XCALLOC(MTYPE_AS_PATH, sizeof(struct aspath)); | |
661 | new->json = NULL; | |
662 | ||
663 | if (aspath->segments) | |
664 | new->segments = assegment_dup_all(aspath->segments); | |
665 | ||
666 | if (!aspath->str) | |
667 | return new; | |
668 | ||
669 | new->str = XMALLOC(MTYPE_AS_STR, buflen); | |
670 | new->str_len = aspath->str_len; | |
671 | ||
672 | /* copy the string data */ | |
673 | if (aspath->str_len > 0) | |
674 | memcpy(new->str, aspath->str, buflen); | |
675 | else | |
676 | new->str[0] = '\0'; | |
677 | ||
678 | return new; | |
679 | } | |
680 | ||
681 | static void *aspath_hash_alloc(void *arg) | |
682 | { | |
683 | const struct aspath *aspath = arg; | |
684 | struct aspath *new; | |
685 | ||
686 | /* Malformed AS path value. */ | |
687 | assert(aspath->str); | |
688 | ||
689 | /* New aspath structure is needed. */ | |
690 | new = XMALLOC(MTYPE_AS_PATH, sizeof(struct aspath)); | |
691 | ||
692 | /* Reuse segments and string representation */ | |
693 | new->refcnt = 0; | |
694 | new->segments = aspath->segments; | |
695 | new->str = aspath->str; | |
696 | new->str_len = aspath->str_len; | |
697 | new->json = aspath->json; | |
698 | ||
699 | return new; | |
700 | } | |
701 | ||
702 | /* parse as-segment byte stream in struct assegment */ | |
703 | static int assegments_parse(struct stream *s, size_t length, | |
704 | struct assegment **result, int use32bit) | |
705 | { | |
706 | struct assegment_header segh; | |
707 | struct assegment *seg, *prev = NULL, *head = NULL; | |
708 | size_t bytes = 0; | |
709 | ||
710 | /* empty aspath (ie iBGP or somesuch) */ | |
711 | if (length == 0) | |
712 | return 0; | |
713 | ||
714 | if (BGP_DEBUG(as4, AS4_SEGMENT)) | |
715 | zlog_debug( | |
716 | "[AS4SEG] Parse aspath segment: got total byte length %lu", | |
717 | (unsigned long)length); | |
718 | /* basic checks */ | |
719 | if ((STREAM_READABLE(s) < length) | |
720 | || (STREAM_READABLE(s) < AS_HEADER_SIZE) | |
721 | || (length % AS16_VALUE_SIZE)) | |
722 | return -1; | |
723 | ||
724 | while (bytes < length) { | |
725 | int i; | |
726 | size_t seg_size; | |
727 | ||
728 | if ((length - bytes) <= AS_HEADER_SIZE) { | |
729 | if (head) | |
730 | assegment_free_all(head); | |
731 | return -1; | |
732 | } | |
733 | ||
734 | /* softly softly, get the header first on its own */ | |
735 | segh.type = stream_getc(s); | |
736 | segh.length = stream_getc(s); | |
737 | ||
738 | seg_size = ASSEGMENT_SIZE(segh.length, use32bit); | |
739 | ||
740 | if (BGP_DEBUG(as4, AS4_SEGMENT)) | |
741 | zlog_debug( | |
742 | "[AS4SEG] Parse aspath segment: got type %d, length %d", | |
743 | segh.type, segh.length); | |
744 | ||
745 | /* check it.. */ | |
746 | if (((bytes + seg_size) > length) | |
747 | /* 1771bis 4.3b: seg length contains one or more */ | |
748 | || (segh.length == 0) | |
749 | /* Paranoia in case someone changes type of segment length. | |
750 | * Shift both values by 0x10 to make the comparison operate | |
751 | * on more, than 8 bits (otherwise it's a warning, bug | |
752 | * #564). | |
753 | */ | |
754 | || ((sizeof segh.length > 1) | |
755 | && (0x10 + segh.length > 0x10 + AS_SEGMENT_MAX))) { | |
756 | if (head) | |
757 | assegment_free_all(head); | |
758 | return -1; | |
759 | } | |
760 | ||
761 | switch (segh.type) { | |
762 | case AS_SEQUENCE: | |
763 | case AS_SET: | |
764 | case AS_CONFED_SEQUENCE: | |
765 | case AS_CONFED_SET: | |
766 | break; | |
767 | default: | |
768 | if (head) | |
769 | assegment_free_all(head); | |
770 | return -1; | |
771 | } | |
772 | ||
773 | /* now its safe to trust lengths */ | |
774 | seg = assegment_new(segh.type, segh.length); | |
775 | ||
776 | if (head) | |
777 | prev->next = seg; | |
778 | else /* it's the first segment */ | |
779 | head = prev = seg; | |
780 | ||
781 | for (i = 0; i < segh.length; i++) | |
782 | seg->as[i] = | |
783 | (use32bit) ? stream_getl(s) : stream_getw(s); | |
784 | ||
785 | bytes += seg_size; | |
786 | ||
787 | if (BGP_DEBUG(as4, AS4_SEGMENT)) | |
788 | zlog_debug( | |
789 | "[AS4SEG] Parse aspath segment: Bytes now: %lu", | |
790 | (unsigned long)bytes); | |
791 | ||
792 | prev = seg; | |
793 | } | |
794 | ||
795 | *result = assegment_normalise(head); | |
796 | return 0; | |
797 | } | |
798 | ||
799 | /* AS path parse function. pnt is a pointer to byte stream and length | |
800 | is length of byte stream. If there is same AS path in the the AS | |
801 | path hash then return it else make new AS path structure. | |
802 | ||
803 | On error NULL is returned. | |
804 | */ | |
805 | struct aspath *aspath_parse(struct stream *s, size_t length, int use32bit) | |
806 | { | |
807 | struct aspath as; | |
808 | struct aspath *find; | |
809 | ||
810 | /* If length is odd it's malformed AS path. */ | |
811 | /* Nit-picking: if (use32bit == 0) it is malformed if odd, | |
812 | * otherwise its malformed when length is larger than 2 and (length-2) | |
813 | * is not dividable by 4. | |
814 | * But... this time we're lazy | |
815 | */ | |
816 | if (length % AS16_VALUE_SIZE) | |
817 | return NULL; | |
818 | ||
819 | memset(&as, 0, sizeof(struct aspath)); | |
820 | if (assegments_parse(s, length, &as.segments, use32bit) < 0) | |
821 | return NULL; | |
822 | ||
823 | /* If already same aspath exist then return it. */ | |
824 | find = hash_get(ashash, &as, aspath_hash_alloc); | |
825 | ||
826 | /* bug! should not happen, let the daemon crash below */ | |
827 | assert(find); | |
828 | ||
829 | /* if the aspath was already hashed free temporary memory. */ | |
830 | if (find->refcnt) { | |
831 | assegment_free_all(as.segments); | |
832 | /* aspath_key_make() always updates the string */ | |
833 | XFREE(MTYPE_AS_STR, as.str); | |
834 | if (as.json) { | |
835 | json_object_free(as.json); | |
836 | as.json = NULL; | |
837 | } | |
838 | } | |
839 | ||
840 | find->refcnt++; | |
841 | ||
842 | return find; | |
843 | } | |
844 | ||
845 | static void assegment_data_put(struct stream *s, as_t *as, int num, | |
846 | int use32bit) | |
847 | { | |
848 | int i; | |
849 | assert(num <= AS_SEGMENT_MAX); | |
850 | ||
851 | for (i = 0; i < num; i++) | |
852 | if (use32bit) | |
853 | stream_putl(s, as[i]); | |
854 | else { | |
855 | if (as[i] <= BGP_AS_MAX) | |
856 | stream_putw(s, as[i]); | |
857 | else | |
858 | stream_putw(s, BGP_AS_TRANS); | |
859 | } | |
860 | } | |
861 | ||
862 | static size_t assegment_header_put(struct stream *s, uint8_t type, int length) | |
863 | { | |
864 | size_t lenp; | |
865 | assert(length <= AS_SEGMENT_MAX); | |
866 | stream_putc(s, type); | |
867 | lenp = stream_get_endp(s); | |
868 | stream_putc(s, length); | |
869 | return lenp; | |
870 | } | |
871 | ||
872 | /* write aspath data to stream */ | |
873 | size_t aspath_put(struct stream *s, struct aspath *as, int use32bit) | |
874 | { | |
875 | struct assegment *seg = as->segments; | |
876 | size_t bytes = 0; | |
877 | ||
878 | if (!seg || seg->length == 0) | |
879 | return 0; | |
880 | ||
881 | if (seg) { | |
882 | /* | |
883 | * Hey, what do we do when we have > STREAM_WRITABLE(s) here? | |
884 | * At the moment, we would write out a partial aspath, and our | |
885 | * peer | |
886 | * will complain and drop the session :-/ | |
887 | * | |
888 | * The general assumption here is that many things tested will | |
889 | * never happen. And, in real live, up to now, they have not. | |
890 | */ | |
891 | while (seg && (ASSEGMENT_LEN(seg, use32bit) | |
892 | <= STREAM_WRITEABLE(s))) { | |
893 | struct assegment *next = seg->next; | |
894 | int written = 0; | |
895 | int asns_packed = 0; | |
896 | size_t lenp; | |
897 | ||
898 | /* Overlength segments have to be split up */ | |
899 | while ((seg->length - written) > AS_SEGMENT_MAX) { | |
900 | assegment_header_put(s, seg->type, | |
901 | AS_SEGMENT_MAX); | |
902 | assegment_data_put(s, seg->as, AS_SEGMENT_MAX, | |
903 | use32bit); | |
904 | written += AS_SEGMENT_MAX; | |
905 | bytes += ASSEGMENT_SIZE(AS_SEGMENT_MAX, | |
906 | use32bit); | |
907 | } | |
908 | ||
909 | /* write the final segment, probably is also the first | |
910 | */ | |
911 | lenp = assegment_header_put(s, seg->type, | |
912 | seg->length - written); | |
913 | assegment_data_put(s, (seg->as + written), | |
914 | seg->length - written, use32bit); | |
915 | ||
916 | /* Sequence-type segments can be 'packed' together | |
917 | * Case of a segment which was overlength and split up | |
918 | * will be missed here, but that doesn't matter. | |
919 | */ | |
920 | while (next && ASSEGMENTS_PACKABLE(seg, next)) { | |
921 | /* NB: We should never normally get here given | |
922 | * we | |
923 | * normalise aspath data when parse them. | |
924 | * However, better | |
925 | * safe than sorry. We potentially could call | |
926 | * assegment_normalise here instead, but it's | |
927 | * cheaper and | |
928 | * easier to do it on the fly here rather than | |
929 | * go through | |
930 | * the segment list twice every time we write | |
931 | * out | |
932 | * aspath's. | |
933 | */ | |
934 | ||
935 | /* Next segment's data can fit in this one */ | |
936 | assegment_data_put(s, next->as, next->length, | |
937 | use32bit); | |
938 | ||
939 | /* update the length of the segment header */ | |
940 | stream_putc_at(s, lenp, | |
941 | seg->length - written | |
942 | + next->length); | |
943 | asns_packed += next->length; | |
944 | ||
945 | next = next->next; | |
946 | } | |
947 | ||
948 | bytes += ASSEGMENT_SIZE( | |
949 | seg->length - written + asns_packed, use32bit); | |
950 | seg = next; | |
951 | } | |
952 | } | |
953 | return bytes; | |
954 | } | |
955 | ||
956 | /* This is for SNMP BGP4PATHATTRASPATHSEGMENT | |
957 | * We have no way to manage the storage, so we use a static stream | |
958 | * wrapper around aspath_put. | |
959 | */ | |
960 | uint8_t *aspath_snmp_pathseg(struct aspath *as, size_t *varlen) | |
961 | { | |
962 | #define SNMP_PATHSEG_MAX 1024 | |
963 | ||
964 | if (!snmp_stream) | |
965 | snmp_stream = stream_new(SNMP_PATHSEG_MAX); | |
966 | else | |
967 | stream_reset(snmp_stream); | |
968 | ||
969 | if (!as) { | |
970 | *varlen = 0; | |
971 | return NULL; | |
972 | } | |
973 | aspath_put(snmp_stream, as, 0); /* use 16 bit for now here */ | |
974 | ||
975 | *varlen = stream_get_endp(snmp_stream); | |
976 | return stream_pnt(snmp_stream); | |
977 | } | |
978 | ||
979 | #define min(A,B) ((A) < (B) ? (A) : (B)) | |
980 | ||
981 | static struct assegment *aspath_aggregate_as_set_add(struct aspath *aspath, | |
982 | struct assegment *asset, | |
983 | as_t as) | |
984 | { | |
985 | int i; | |
986 | ||
987 | /* If this is first AS set member, create new as-set segment. */ | |
988 | if (asset == NULL) { | |
989 | asset = assegment_new(AS_SET, 1); | |
990 | if (!aspath->segments) | |
991 | aspath->segments = asset; | |
992 | else { | |
993 | struct assegment *seg = aspath->segments; | |
994 | while (seg->next) | |
995 | seg = seg->next; | |
996 | seg->next = asset; | |
997 | } | |
998 | asset->type = AS_SET; | |
999 | asset->length = 1; | |
1000 | asset->as[0] = as; | |
1001 | } else { | |
1002 | /* Check this AS value already exists or not. */ | |
1003 | for (i = 0; i < asset->length; i++) | |
1004 | if (asset->as[i] == as) | |
1005 | return asset; | |
1006 | ||
1007 | asset->length++; | |
1008 | asset->as = XREALLOC(MTYPE_AS_SEG_DATA, asset->as, | |
1009 | asset->length * AS_VALUE_SIZE); | |
1010 | asset->as[asset->length - 1] = as; | |
1011 | } | |
1012 | ||
1013 | ||
1014 | return asset; | |
1015 | } | |
1016 | ||
1017 | /* Modify as1 using as2 for aggregation. */ | |
1018 | struct aspath *aspath_aggregate(struct aspath *as1, struct aspath *as2) | |
1019 | { | |
1020 | int i; | |
1021 | int minlen = 0; | |
1022 | int match = 0; | |
1023 | int from; | |
1024 | struct assegment *seg1 = as1->segments; | |
1025 | struct assegment *seg2 = as2->segments; | |
1026 | struct aspath *aspath = NULL; | |
1027 | struct assegment *asset = NULL; | |
1028 | struct assegment *prevseg = NULL; | |
1029 | ||
1030 | /* First of all check common leading sequence. */ | |
1031 | while (seg1 && seg2) { | |
1032 | /* Check segment type. */ | |
1033 | if (seg1->type != seg2->type) | |
1034 | break; | |
1035 | ||
1036 | /* Minimum segment length. */ | |
1037 | minlen = min(seg1->length, seg2->length); | |
1038 | ||
1039 | for (match = 0; match < minlen; match++) | |
1040 | if (seg1->as[match] != seg2->as[match]) | |
1041 | break; | |
1042 | ||
1043 | if (match) { | |
1044 | struct assegment *seg = assegment_new(seg1->type, 0); | |
1045 | ||
1046 | seg = assegment_append_asns(seg, seg1->as, match); | |
1047 | ||
1048 | if (!aspath) { | |
1049 | aspath = aspath_new(); | |
1050 | aspath->segments = seg; | |
1051 | } else | |
1052 | prevseg->next = seg; | |
1053 | ||
1054 | prevseg = seg; | |
1055 | } | |
1056 | ||
1057 | if (match != minlen || match != seg1->length | |
1058 | || seg1->length != seg2->length) | |
1059 | break; | |
1060 | /* We are moving on to the next segment to reset match */ | |
1061 | else | |
1062 | match = 0; | |
1063 | ||
1064 | seg1 = seg1->next; | |
1065 | seg2 = seg2->next; | |
1066 | } | |
1067 | ||
1068 | if (!aspath) | |
1069 | aspath = aspath_new(); | |
1070 | ||
1071 | /* Make as-set using rest of all information. */ | |
1072 | from = match; | |
1073 | while (seg1) { | |
1074 | for (i = from; i < seg1->length; i++) | |
1075 | asset = aspath_aggregate_as_set_add(aspath, asset, | |
1076 | seg1->as[i]); | |
1077 | ||
1078 | from = 0; | |
1079 | seg1 = seg1->next; | |
1080 | } | |
1081 | ||
1082 | from = match; | |
1083 | while (seg2) { | |
1084 | for (i = from; i < seg2->length; i++) | |
1085 | asset = aspath_aggregate_as_set_add(aspath, asset, | |
1086 | seg2->as[i]); | |
1087 | ||
1088 | from = 0; | |
1089 | seg2 = seg2->next; | |
1090 | } | |
1091 | ||
1092 | assegment_normalise(aspath->segments); | |
1093 | aspath_str_update(aspath, false); | |
1094 | return aspath; | |
1095 | } | |
1096 | ||
1097 | /* When a BGP router receives an UPDATE with an MP_REACH_NLRI | |
1098 | attribute, check the leftmost AS number in the AS_PATH attribute is | |
1099 | or not the peer's AS number. */ | |
1100 | int aspath_firstas_check(struct aspath *aspath, as_t asno) | |
1101 | { | |
1102 | if ((aspath == NULL) || (aspath->segments == NULL)) | |
1103 | return 0; | |
1104 | ||
1105 | if (aspath->segments && (aspath->segments->type == AS_SEQUENCE) | |
1106 | && (aspath->segments->as[0] == asno)) | |
1107 | return 1; | |
1108 | ||
1109 | return 0; | |
1110 | } | |
1111 | ||
1112 | unsigned int aspath_get_first_as(struct aspath *aspath) | |
1113 | { | |
1114 | if (aspath == NULL || aspath->segments == NULL) | |
1115 | return 0; | |
1116 | ||
1117 | return aspath->segments->as[0]; | |
1118 | } | |
1119 | ||
1120 | unsigned int aspath_get_last_as(struct aspath *aspath) | |
1121 | { | |
1122 | int i; | |
1123 | unsigned int last_as = 0; | |
1124 | const struct assegment *seg; | |
1125 | ||
1126 | if (aspath == NULL || aspath->segments == NULL) | |
1127 | return last_as; | |
1128 | ||
1129 | seg = aspath->segments; | |
1130 | ||
1131 | while (seg) { | |
1132 | if (seg->type == AS_SEQUENCE || seg->type == AS_CONFED_SEQUENCE) | |
1133 | for (i = 0; i < seg->length; i++) | |
1134 | last_as = seg->as[i]; | |
1135 | seg = seg->next; | |
1136 | } | |
1137 | ||
1138 | return last_as; | |
1139 | } | |
1140 | ||
1141 | /* AS path loop check. If aspath contains asno then return >= 1. */ | |
1142 | int aspath_loop_check(struct aspath *aspath, as_t asno) | |
1143 | { | |
1144 | struct assegment *seg; | |
1145 | int count = 0; | |
1146 | ||
1147 | if ((aspath == NULL) || (aspath->segments == NULL)) | |
1148 | return 0; | |
1149 | ||
1150 | seg = aspath->segments; | |
1151 | ||
1152 | while (seg) { | |
1153 | int i; | |
1154 | ||
1155 | for (i = 0; i < seg->length; i++) | |
1156 | if (seg->as[i] == asno) | |
1157 | count++; | |
1158 | ||
1159 | seg = seg->next; | |
1160 | } | |
1161 | return count; | |
1162 | } | |
1163 | ||
1164 | /* When all of AS path is private AS return 1. */ | |
1165 | int aspath_private_as_check(struct aspath *aspath) | |
1166 | { | |
1167 | struct assegment *seg; | |
1168 | ||
1169 | if (!(aspath && aspath->segments)) | |
1170 | return 0; | |
1171 | ||
1172 | seg = aspath->segments; | |
1173 | ||
1174 | while (seg) { | |
1175 | int i; | |
1176 | ||
1177 | for (i = 0; i < seg->length; i++) { | |
1178 | if (!BGP_AS_IS_PRIVATE(seg->as[i])) | |
1179 | return 0; | |
1180 | } | |
1181 | seg = seg->next; | |
1182 | } | |
1183 | return 1; | |
1184 | } | |
1185 | ||
1186 | /* Return True if the entire ASPATH consist of the specified ASN */ | |
1187 | int aspath_single_asn_check(struct aspath *aspath, as_t asn) | |
1188 | { | |
1189 | struct assegment *seg; | |
1190 | ||
1191 | if (!(aspath && aspath->segments)) | |
1192 | return 0; | |
1193 | ||
1194 | seg = aspath->segments; | |
1195 | ||
1196 | while (seg) { | |
1197 | int i; | |
1198 | ||
1199 | for (i = 0; i < seg->length; i++) { | |
1200 | if (seg->as[i] != asn) | |
1201 | return 0; | |
1202 | } | |
1203 | seg = seg->next; | |
1204 | } | |
1205 | return 1; | |
1206 | } | |
1207 | ||
1208 | /* Replace all instances of the target ASN with our own ASN */ | |
1209 | struct aspath *aspath_replace_specific_asn(struct aspath *aspath, | |
1210 | as_t target_asn, as_t our_asn) | |
1211 | { | |
1212 | struct aspath *new; | |
1213 | struct assegment *seg; | |
1214 | ||
1215 | new = aspath_dup(aspath); | |
1216 | seg = new->segments; | |
1217 | ||
1218 | while (seg) { | |
1219 | int i; | |
1220 | ||
1221 | for (i = 0; i < seg->length; i++) { | |
1222 | if (seg->as[i] == target_asn) | |
1223 | seg->as[i] = our_asn; | |
1224 | } | |
1225 | seg = seg->next; | |
1226 | } | |
1227 | ||
1228 | aspath_str_update(new, false); | |
1229 | return new; | |
1230 | } | |
1231 | ||
1232 | /* Replace all private ASNs with our own ASN */ | |
1233 | struct aspath *aspath_replace_private_asns(struct aspath *aspath, as_t asn) | |
1234 | { | |
1235 | struct aspath *new; | |
1236 | struct assegment *seg; | |
1237 | ||
1238 | new = aspath_dup(aspath); | |
1239 | seg = new->segments; | |
1240 | ||
1241 | while (seg) { | |
1242 | int i; | |
1243 | ||
1244 | for (i = 0; i < seg->length; i++) { | |
1245 | if (BGP_AS_IS_PRIVATE(seg->as[i])) | |
1246 | seg->as[i] = asn; | |
1247 | } | |
1248 | seg = seg->next; | |
1249 | } | |
1250 | ||
1251 | aspath_str_update(new, false); | |
1252 | return new; | |
1253 | } | |
1254 | ||
1255 | /* Remove all private ASNs */ | |
1256 | struct aspath *aspath_remove_private_asns(struct aspath *aspath) | |
1257 | { | |
1258 | struct aspath *new; | |
1259 | struct assegment *seg; | |
1260 | struct assegment *new_seg; | |
1261 | struct assegment *last_new_seg; | |
1262 | int i; | |
1263 | int j; | |
1264 | int public = 0; | |
1265 | ||
1266 | new = XCALLOC(MTYPE_AS_PATH, sizeof(struct aspath)); | |
1267 | ||
1268 | new->json = NULL; | |
1269 | new_seg = NULL; | |
1270 | last_new_seg = NULL; | |
1271 | seg = aspath->segments; | |
1272 | while (seg) { | |
1273 | public | |
1274 | = 0; | |
1275 | for (i = 0; i < seg->length; i++) { | |
1276 | // ASN is public | |
1277 | if (!BGP_AS_IS_PRIVATE(seg->as[i])) { | |
1278 | public | |
1279 | ++; | |
1280 | } | |
1281 | } | |
1282 | ||
1283 | // The entire segment is private so skip it | |
1284 | if (!public) { | |
1285 | seg = seg->next; | |
1286 | continue; | |
1287 | } | |
1288 | ||
1289 | // The entire segment is public so copy it | |
1290 | else if (public == seg->length) { | |
1291 | new_seg = assegment_dup(seg); | |
1292 | } | |
1293 | ||
1294 | // The segment is a mix of public and private ASNs. Copy as many | |
1295 | // spots as | |
1296 | // there are public ASNs then come back and fill in only the | |
1297 | // public ASNs. | |
1298 | else { | |
1299 | new_seg = assegment_new(seg->type, public); | |
1300 | j = 0; | |
1301 | for (i = 0; i < seg->length; i++) { | |
1302 | // ASN is public | |
1303 | if (!BGP_AS_IS_PRIVATE(seg->as[i])) { | |
1304 | new_seg->as[j] = seg->as[i]; | |
1305 | j++; | |
1306 | } | |
1307 | } | |
1308 | } | |
1309 | ||
1310 | // This is the first segment so set the aspath segments pointer | |
1311 | // to this one | |
1312 | if (!last_new_seg) | |
1313 | new->segments = new_seg; | |
1314 | else | |
1315 | last_new_seg->next = new_seg; | |
1316 | ||
1317 | last_new_seg = new_seg; | |
1318 | seg = seg->next; | |
1319 | } | |
1320 | ||
1321 | aspath_str_update(new, false); | |
1322 | return new; | |
1323 | } | |
1324 | ||
1325 | /* AS path confed check. If aspath contains confed set or sequence then return | |
1326 | * 1. */ | |
1327 | int aspath_confed_check(struct aspath *aspath) | |
1328 | { | |
1329 | struct assegment *seg; | |
1330 | ||
1331 | if (!(aspath && aspath->segments)) | |
1332 | return 0; | |
1333 | ||
1334 | seg = aspath->segments; | |
1335 | ||
1336 | while (seg) { | |
1337 | if (seg->type == AS_CONFED_SET | |
1338 | || seg->type == AS_CONFED_SEQUENCE) | |
1339 | return 1; | |
1340 | seg = seg->next; | |
1341 | } | |
1342 | return 0; | |
1343 | } | |
1344 | ||
1345 | /* Leftmost AS path segment confed check. If leftmost AS segment is of type | |
1346 | AS_CONFED_SEQUENCE or AS_CONFED_SET then return 1. */ | |
1347 | int aspath_left_confed_check(struct aspath *aspath) | |
1348 | { | |
1349 | ||
1350 | if (!(aspath && aspath->segments)) | |
1351 | return 0; | |
1352 | ||
1353 | if ((aspath->segments->type == AS_CONFED_SEQUENCE) | |
1354 | || (aspath->segments->type == AS_CONFED_SET)) | |
1355 | return 1; | |
1356 | ||
1357 | return 0; | |
1358 | } | |
1359 | ||
1360 | /* Merge as1 to as2. as2 should be uninterned aspath. */ | |
1361 | static struct aspath *aspath_merge(struct aspath *as1, struct aspath *as2) | |
1362 | { | |
1363 | struct assegment *last, *new; | |
1364 | ||
1365 | if (!as1 || !as2) | |
1366 | return NULL; | |
1367 | ||
1368 | last = new = assegment_dup_all(as1->segments); | |
1369 | ||
1370 | /* find the last valid segment */ | |
1371 | while (last && last->next) | |
1372 | last = last->next; | |
1373 | ||
1374 | last->next = as2->segments; | |
1375 | as2->segments = new; | |
1376 | aspath_str_update(as2, false); | |
1377 | return as2; | |
1378 | } | |
1379 | ||
1380 | /* Prepend as1 to as2. as2 should be uninterned aspath. */ | |
1381 | struct aspath *aspath_prepend(struct aspath *as1, struct aspath *as2) | |
1382 | { | |
1383 | struct assegment *seg1; | |
1384 | struct assegment *seg2; | |
1385 | ||
1386 | if (!as1 || !as2) | |
1387 | return NULL; | |
1388 | ||
1389 | seg1 = as1->segments; | |
1390 | seg2 = as2->segments; | |
1391 | ||
1392 | /* If as2 is empty, only need to dupe as1's chain onto as2 */ | |
1393 | if (seg2 == NULL) { | |
1394 | as2->segments = assegment_dup_all(as1->segments); | |
1395 | aspath_str_update(as2, false); | |
1396 | return as2; | |
1397 | } | |
1398 | ||
1399 | /* If as1 is empty AS, no prepending to do. */ | |
1400 | if (seg1 == NULL) | |
1401 | return as2; | |
1402 | ||
1403 | /* find the tail as1's segment chain. */ | |
1404 | while (seg1 && seg1->next) | |
1405 | seg1 = seg1->next; | |
1406 | ||
1407 | /* Delete any AS_CONFED_SEQUENCE segment from as2. */ | |
1408 | if (seg1->type == AS_SEQUENCE && seg2->type == AS_CONFED_SEQUENCE) | |
1409 | as2 = aspath_delete_confed_seq(as2); | |
1410 | ||
1411 | /* Compare last segment type of as1 and first segment type of as2. */ | |
1412 | if (seg1->type != seg2->type) | |
1413 | return aspath_merge(as1, as2); | |
1414 | ||
1415 | if (seg1->type == AS_SEQUENCE) { | |
1416 | /* We have two chains of segments, as1->segments and seg2, | |
1417 | * and we have to attach them together, merging the attaching | |
1418 | * segments together into one. | |
1419 | * | |
1420 | * 1. dupe as1->segments onto head of as2 | |
1421 | * 2. merge seg2's asns onto last segment of this new chain | |
1422 | * 3. attach chain after seg2 | |
1423 | */ | |
1424 | ||
1425 | /* dupe as1 onto as2's head */ | |
1426 | seg1 = as2->segments = assegment_dup_all(as1->segments); | |
1427 | ||
1428 | /* refind the tail of as2, reusing seg1 */ | |
1429 | while (seg1 && seg1->next) | |
1430 | seg1 = seg1->next; | |
1431 | ||
1432 | /* merge the old head, seg2, into tail, seg1 */ | |
1433 | seg1 = assegment_append_asns(seg1, seg2->as, seg2->length); | |
1434 | ||
1435 | /* bypass the merged seg2, and attach any chain after it to | |
1436 | * chain descending from as2's head | |
1437 | */ | |
1438 | seg1->next = seg2->next; | |
1439 | ||
1440 | /* seg2 is now referenceless and useless*/ | |
1441 | assegment_free(seg2); | |
1442 | ||
1443 | /* we've now prepended as1's segment chain to as2, merging | |
1444 | * the inbetween AS_SEQUENCE of seg2 in the process | |
1445 | */ | |
1446 | aspath_str_update(as2, false); | |
1447 | return as2; | |
1448 | } else { | |
1449 | /* AS_SET merge code is needed at here. */ | |
1450 | return aspath_merge(as1, as2); | |
1451 | } | |
1452 | /* XXX: Ermmm, what if as1 has multiple segments?? */ | |
1453 | ||
1454 | /* Not reached */ | |
1455 | } | |
1456 | ||
1457 | /* Iterate over AS_PATH segments and wipe all occurences of the | |
1458 | * listed AS numbers. Hence some segments may lose some or even | |
1459 | * all data on the way, the operation is implemented as a smarter | |
1460 | * version of aspath_dup(), which allocates memory to hold the new | |
1461 | * data, not the original. The new AS path is returned. | |
1462 | */ | |
1463 | struct aspath *aspath_filter_exclude(struct aspath *source, | |
1464 | struct aspath *exclude_list) | |
1465 | { | |
1466 | struct assegment *srcseg, *exclseg, *lastseg; | |
1467 | struct aspath *newpath; | |
1468 | ||
1469 | newpath = aspath_new(); | |
1470 | lastseg = NULL; | |
1471 | ||
1472 | for (srcseg = source->segments; srcseg; srcseg = srcseg->next) { | |
1473 | unsigned i, y, newlen = 0, done = 0, skip_as; | |
1474 | struct assegment *newseg; | |
1475 | ||
1476 | /* Find out, how much ASns are we going to pick from this | |
1477 | * segment. | |
1478 | * We can't perform filtering right inline, because the size of | |
1479 | * the new segment isn't known at the moment yet. | |
1480 | */ | |
1481 | for (i = 0; i < srcseg->length; i++) { | |
1482 | skip_as = 0; | |
1483 | for (exclseg = exclude_list->segments; | |
1484 | exclseg && !skip_as; exclseg = exclseg->next) | |
1485 | for (y = 0; y < exclseg->length; y++) | |
1486 | if (srcseg->as[i] == exclseg->as[y]) { | |
1487 | skip_as = 1; | |
1488 | // There's no sense in testing | |
1489 | // the rest of exclusion list, | |
1490 | // bail out. | |
1491 | break; | |
1492 | } | |
1493 | if (!skip_as) | |
1494 | newlen++; | |
1495 | } | |
1496 | /* newlen is now the number of ASns to copy */ | |
1497 | if (!newlen) | |
1498 | continue; | |
1499 | ||
1500 | /* Actual copying. Allocate memory and iterate once more, | |
1501 | * performing filtering. */ | |
1502 | newseg = assegment_new(srcseg->type, newlen); | |
1503 | for (i = 0; i < srcseg->length; i++) { | |
1504 | skip_as = 0; | |
1505 | for (exclseg = exclude_list->segments; | |
1506 | exclseg && !skip_as; exclseg = exclseg->next) | |
1507 | for (y = 0; y < exclseg->length; y++) | |
1508 | if (srcseg->as[i] == exclseg->as[y]) { | |
1509 | skip_as = 1; | |
1510 | break; | |
1511 | } | |
1512 | if (skip_as) | |
1513 | continue; | |
1514 | newseg->as[done++] = srcseg->as[i]; | |
1515 | } | |
1516 | /* At his point newlen must be equal to done, and both must be | |
1517 | * positive. Append | |
1518 | * the filtered segment to the gross result. */ | |
1519 | if (!lastseg) | |
1520 | newpath->segments = newseg; | |
1521 | else | |
1522 | lastseg->next = newseg; | |
1523 | lastseg = newseg; | |
1524 | } | |
1525 | aspath_str_update(newpath, false); | |
1526 | /* We are happy returning even an empty AS_PATH, because the | |
1527 | * administrator | |
1528 | * might expect this very behaviour. There's a mean to avoid this, if | |
1529 | * necessary, | |
1530 | * by having a match rule against certain AS_PATH regexps in the | |
1531 | * route-map index. | |
1532 | */ | |
1533 | aspath_free(source); | |
1534 | return newpath; | |
1535 | } | |
1536 | ||
1537 | /* Add specified AS to the leftmost of aspath. */ | |
1538 | static struct aspath *aspath_add_asns(struct aspath *aspath, as_t asno, | |
1539 | uint8_t type, unsigned num) | |
1540 | { | |
1541 | struct assegment *assegment = aspath->segments; | |
1542 | unsigned i; | |
1543 | ||
1544 | if (assegment && assegment->type == type) { | |
1545 | /* extend existing segment */ | |
1546 | aspath->segments = | |
1547 | assegment_prepend_asns(aspath->segments, asno, num); | |
1548 | } else { | |
1549 | /* prepend with new segment */ | |
1550 | struct assegment *newsegment = assegment_new(type, num); | |
1551 | for (i = 0; i < num; i++) | |
1552 | newsegment->as[i] = asno; | |
1553 | ||
1554 | /* insert potentially replacing empty segment */ | |
1555 | if (assegment && assegment->length == 0) { | |
1556 | newsegment->next = assegment->next; | |
1557 | assegment_free(assegment); | |
1558 | } else | |
1559 | newsegment->next = assegment; | |
1560 | aspath->segments = newsegment; | |
1561 | } | |
1562 | ||
1563 | aspath_str_update(aspath, false); | |
1564 | return aspath; | |
1565 | } | |
1566 | ||
1567 | /* Add specified AS to the leftmost of aspath num times. */ | |
1568 | struct aspath *aspath_add_seq_n(struct aspath *aspath, as_t asno, unsigned num) | |
1569 | { | |
1570 | return aspath_add_asns(aspath, asno, AS_SEQUENCE, num); | |
1571 | } | |
1572 | ||
1573 | /* Add specified AS to the leftmost of aspath. */ | |
1574 | struct aspath *aspath_add_seq(struct aspath *aspath, as_t asno) | |
1575 | { | |
1576 | return aspath_add_asns(aspath, asno, AS_SEQUENCE, 1); | |
1577 | } | |
1578 | ||
1579 | /* Compare leftmost AS value for MED check. If as1's leftmost AS and | |
1580 | as2's leftmost AS is same return 1. */ | |
1581 | int aspath_cmp_left(const struct aspath *aspath1, const struct aspath *aspath2) | |
1582 | { | |
1583 | const struct assegment *seg1; | |
1584 | const struct assegment *seg2; | |
1585 | ||
1586 | if (!(aspath1 && aspath2)) | |
1587 | return 0; | |
1588 | ||
1589 | seg1 = aspath1->segments; | |
1590 | seg2 = aspath2->segments; | |
1591 | ||
1592 | /* If both paths are originated in this AS then we do want to compare | |
1593 | * MED */ | |
1594 | if (!seg1 && !seg2) | |
1595 | return 1; | |
1596 | ||
1597 | /* find first non-confed segments for each */ | |
1598 | while (seg1 && ((seg1->type == AS_CONFED_SEQUENCE) | |
1599 | || (seg1->type == AS_CONFED_SET))) | |
1600 | seg1 = seg1->next; | |
1601 | ||
1602 | while (seg2 && ((seg2->type == AS_CONFED_SEQUENCE) | |
1603 | || (seg2->type == AS_CONFED_SET))) | |
1604 | seg2 = seg2->next; | |
1605 | ||
1606 | /* Check as1's */ | |
1607 | if (!(seg1 && seg2 && (seg1->type == AS_SEQUENCE) | |
1608 | && (seg2->type == AS_SEQUENCE))) | |
1609 | return 0; | |
1610 | ||
1611 | if (seg1->as[0] == seg2->as[0]) | |
1612 | return 1; | |
1613 | ||
1614 | return 0; | |
1615 | } | |
1616 | ||
1617 | /* Truncate an aspath after a number of hops, and put the hops remaining | |
1618 | * at the front of another aspath. Needed for AS4 compat. | |
1619 | * | |
1620 | * Returned aspath is a /new/ aspath, which should either by free'd or | |
1621 | * interned by the caller, as desired. | |
1622 | */ | |
1623 | struct aspath *aspath_reconcile_as4(struct aspath *aspath, | |
1624 | struct aspath *as4path) | |
1625 | { | |
1626 | struct assegment *seg, *newseg, *prevseg = NULL; | |
1627 | struct aspath *newpath = NULL, *mergedpath; | |
1628 | int hops, cpasns = 0; | |
1629 | ||
1630 | if (!aspath || !as4path) | |
1631 | return NULL; | |
1632 | ||
1633 | seg = aspath->segments; | |
1634 | ||
1635 | /* CONFEDs should get reconciled too.. */ | |
1636 | hops = (aspath_count_hops(aspath) + aspath_count_confeds(aspath)) | |
1637 | - aspath_count_hops(as4path); | |
1638 | ||
1639 | if (hops < 0) { | |
1640 | if (BGP_DEBUG(as4, AS4)) | |
1641 | zlog_warn( | |
1642 | "[AS4] Fewer hops in AS_PATH than NEW_AS_PATH"); | |
1643 | /* Something's gone wrong. The RFC says we should now ignore | |
1644 | * AS4_PATH, | |
1645 | * which is daft behaviour - it contains vital loop-detection | |
1646 | * information which must have been removed from AS_PATH. | |
1647 | */ | |
1648 | hops = aspath_count_hops(aspath); | |
1649 | } | |
1650 | ||
1651 | if (!hops) { | |
1652 | newpath = aspath_dup(as4path); | |
1653 | aspath_str_update(newpath, false); | |
1654 | return newpath; | |
1655 | } | |
1656 | ||
1657 | if (BGP_DEBUG(as4, AS4)) | |
1658 | zlog_debug( | |
1659 | "[AS4] got AS_PATH %s and AS4_PATH %s synthesizing now", | |
1660 | aspath->str, as4path->str); | |
1661 | ||
1662 | while (seg && hops > 0) { | |
1663 | switch (seg->type) { | |
1664 | case AS_SET: | |
1665 | case AS_CONFED_SET: | |
1666 | hops--; | |
1667 | cpasns = seg->length; | |
1668 | break; | |
1669 | case AS_CONFED_SEQUENCE: | |
1670 | /* Should never split a confed-sequence, if hop-count | |
1671 | * suggests we must then something's gone wrong | |
1672 | * somewhere. | |
1673 | * | |
1674 | * Most important goal is to preserve AS_PATHs prime | |
1675 | * function | |
1676 | * as loop-detector, so we fudge the numbers so that the | |
1677 | * entire | |
1678 | * confed-sequence is merged in. | |
1679 | */ | |
1680 | if (hops < seg->length) { | |
1681 | if (BGP_DEBUG(as4, AS4)) | |
1682 | zlog_debug( | |
1683 | "[AS4] AS4PATHmangle: AS_CONFED_SEQUENCE falls" | |
1684 | " across 2/4 ASN boundary somewhere, broken.."); | |
1685 | hops = seg->length; | |
1686 | } | |
1687 | /* fallthru */ | |
1688 | case AS_SEQUENCE: | |
1689 | cpasns = MIN(seg->length, hops); | |
1690 | hops -= seg->length; | |
1691 | } | |
1692 | ||
1693 | assert(cpasns <= seg->length); | |
1694 | ||
1695 | newseg = assegment_new(seg->type, 0); | |
1696 | newseg = assegment_append_asns(newseg, seg->as, cpasns); | |
1697 | ||
1698 | if (!newpath) { | |
1699 | newpath = aspath_new(); | |
1700 | newpath->segments = newseg; | |
1701 | } else | |
1702 | prevseg->next = newseg; | |
1703 | ||
1704 | prevseg = newseg; | |
1705 | seg = seg->next; | |
1706 | } | |
1707 | ||
1708 | /* We may be able to join some segments here, and we must | |
1709 | * do this because... we want normalised aspaths in out hash | |
1710 | * and we do not want to stumble in aspath_put. | |
1711 | */ | |
1712 | mergedpath = aspath_merge(newpath, aspath_dup(as4path)); | |
1713 | aspath_free(newpath); | |
1714 | mergedpath->segments = assegment_normalise(mergedpath->segments); | |
1715 | aspath_str_update(mergedpath, false); | |
1716 | ||
1717 | if (BGP_DEBUG(as4, AS4)) | |
1718 | zlog_debug("[AS4] result of synthesizing is %s", | |
1719 | mergedpath->str); | |
1720 | ||
1721 | return mergedpath; | |
1722 | } | |
1723 | ||
1724 | /* Compare leftmost AS value for MED check. If as1's leftmost AS and | |
1725 | as2's leftmost AS is same return 1. (confederation as-path | |
1726 | only). */ | |
1727 | int aspath_cmp_left_confed(const struct aspath *aspath1, | |
1728 | const struct aspath *aspath2) | |
1729 | { | |
1730 | if (!(aspath1 && aspath2)) | |
1731 | return 0; | |
1732 | ||
1733 | if (!(aspath1->segments && aspath2->segments)) | |
1734 | return 0; | |
1735 | ||
1736 | if ((aspath1->segments->type != AS_CONFED_SEQUENCE) | |
1737 | || (aspath2->segments->type != AS_CONFED_SEQUENCE)) | |
1738 | return 0; | |
1739 | ||
1740 | if (aspath1->segments->as[0] == aspath2->segments->as[0]) | |
1741 | return 1; | |
1742 | ||
1743 | return 0; | |
1744 | } | |
1745 | ||
1746 | /* Delete all AS_CONFED_SEQUENCE/SET segments from aspath. | |
1747 | * RFC 5065 section 4.1.c.1 | |
1748 | * | |
1749 | * 1) if any path segments of the AS_PATH are of the type | |
1750 | * AS_CONFED_SEQUENCE or AS_CONFED_SET, those segments MUST be | |
1751 | * removed from the AS_PATH attribute, leaving the sanitized | |
1752 | * AS_PATH attribute to be operated on by steps 2, 3 or 4. | |
1753 | */ | |
1754 | struct aspath *aspath_delete_confed_seq(struct aspath *aspath) | |
1755 | { | |
1756 | struct assegment *seg, *prev, *next; | |
1757 | char removed_confed_segment; | |
1758 | ||
1759 | if (!(aspath && aspath->segments)) | |
1760 | return aspath; | |
1761 | ||
1762 | seg = aspath->segments; | |
1763 | removed_confed_segment = 0; | |
1764 | next = NULL; | |
1765 | prev = NULL; | |
1766 | ||
1767 | while (seg) { | |
1768 | next = seg->next; | |
1769 | ||
1770 | if (seg->type == AS_CONFED_SEQUENCE | |
1771 | || seg->type == AS_CONFED_SET) { | |
1772 | /* This is the first segment in the aspath */ | |
1773 | if (aspath->segments == seg) | |
1774 | aspath->segments = seg->next; | |
1775 | else | |
1776 | prev->next = seg->next; | |
1777 | ||
1778 | assegment_free(seg); | |
1779 | removed_confed_segment = 1; | |
1780 | } else | |
1781 | prev = seg; | |
1782 | ||
1783 | seg = next; | |
1784 | } | |
1785 | ||
1786 | if (removed_confed_segment) | |
1787 | aspath_str_update(aspath, false); | |
1788 | ||
1789 | return aspath; | |
1790 | } | |
1791 | ||
1792 | /* Add new AS number to the leftmost part of the aspath as | |
1793 | AS_CONFED_SEQUENCE. */ | |
1794 | struct aspath *aspath_add_confed_seq(struct aspath *aspath, as_t asno) | |
1795 | { | |
1796 | return aspath_add_asns(aspath, asno, AS_CONFED_SEQUENCE, 1); | |
1797 | } | |
1798 | ||
1799 | /* Add new as value to as path structure. */ | |
1800 | static void aspath_as_add(struct aspath *as, as_t asno) | |
1801 | { | |
1802 | struct assegment *seg = as->segments; | |
1803 | ||
1804 | if (!seg) | |
1805 | return; | |
1806 | ||
1807 | /* Last segment search procedure. */ | |
1808 | while (seg->next) | |
1809 | seg = seg->next; | |
1810 | ||
1811 | assegment_append_asns(seg, &asno, 1); | |
1812 | } | |
1813 | ||
1814 | /* Add new as segment to the as path. */ | |
1815 | static void aspath_segment_add(struct aspath *as, int type) | |
1816 | { | |
1817 | struct assegment *seg = as->segments; | |
1818 | struct assegment *new = assegment_new(type, 0); | |
1819 | ||
1820 | if (seg) { | |
1821 | while (seg->next) | |
1822 | seg = seg->next; | |
1823 | seg->next = new; | |
1824 | } else | |
1825 | as->segments = new; | |
1826 | } | |
1827 | ||
1828 | struct aspath *aspath_empty(void) | |
1829 | { | |
1830 | return aspath_parse(NULL, 0, 1); /* 32Bit ;-) */ | |
1831 | } | |
1832 | ||
1833 | struct aspath *aspath_empty_get(void) | |
1834 | { | |
1835 | struct aspath *aspath; | |
1836 | ||
1837 | aspath = aspath_new(); | |
1838 | aspath_make_str_count(aspath, false); | |
1839 | return aspath; | |
1840 | } | |
1841 | ||
1842 | unsigned long aspath_count(void) | |
1843 | { | |
1844 | return ashash->count; | |
1845 | } | |
1846 | ||
1847 | /* | |
1848 | Theoretically, one as path can have: | |
1849 | ||
1850 | One BGP packet size should be less than 4096. | |
1851 | One BGP attribute size should be less than 4096 - BGP header size. | |
1852 | One BGP aspath size should be less than 4096 - BGP header size - | |
1853 | BGP mandantry attribute size. | |
1854 | */ | |
1855 | ||
1856 | /* AS path string lexical token enum. */ | |
1857 | enum as_token { | |
1858 | as_token_asval, | |
1859 | as_token_set_start, | |
1860 | as_token_set_end, | |
1861 | as_token_confed_seq_start, | |
1862 | as_token_confed_seq_end, | |
1863 | as_token_confed_set_start, | |
1864 | as_token_confed_set_end, | |
1865 | as_token_unknown | |
1866 | }; | |
1867 | ||
1868 | /* Return next token and point for string parse. */ | |
1869 | static const char *aspath_gettoken(const char *buf, enum as_token *token, | |
1870 | unsigned long *asno) | |
1871 | { | |
1872 | const char *p = buf; | |
1873 | ||
1874 | /* Skip seperators (space for sequences, ',' for sets). */ | |
1875 | while (isspace((int)*p) || *p == ',') | |
1876 | p++; | |
1877 | ||
1878 | /* Check the end of the string and type specify characters | |
1879 | (e.g. {}()). */ | |
1880 | switch (*p) { | |
1881 | case '\0': | |
1882 | return NULL; | |
1883 | case '{': | |
1884 | *token = as_token_set_start; | |
1885 | p++; | |
1886 | return p; | |
1887 | case '}': | |
1888 | *token = as_token_set_end; | |
1889 | p++; | |
1890 | return p; | |
1891 | case '(': | |
1892 | *token = as_token_confed_seq_start; | |
1893 | p++; | |
1894 | return p; | |
1895 | case ')': | |
1896 | *token = as_token_confed_seq_end; | |
1897 | p++; | |
1898 | return p; | |
1899 | case '[': | |
1900 | *token = as_token_confed_set_start; | |
1901 | p++; | |
1902 | return p; | |
1903 | case ']': | |
1904 | *token = as_token_confed_set_end; | |
1905 | p++; | |
1906 | return p; | |
1907 | } | |
1908 | ||
1909 | /* Check actual AS value. */ | |
1910 | if (isdigit((int)*p)) { | |
1911 | as_t asval; | |
1912 | ||
1913 | *token = as_token_asval; | |
1914 | asval = (*p - '0'); | |
1915 | p++; | |
1916 | ||
1917 | while (isdigit((int)*p)) { | |
1918 | asval *= 10; | |
1919 | asval += (*p - '0'); | |
1920 | p++; | |
1921 | } | |
1922 | *asno = asval; | |
1923 | return p; | |
1924 | } | |
1925 | ||
1926 | /* There is no match then return unknown token. */ | |
1927 | *token = as_token_unknown; | |
1928 | p++; | |
1929 | return p; | |
1930 | } | |
1931 | ||
1932 | struct aspath *aspath_str2aspath(const char *str) | |
1933 | { | |
1934 | enum as_token token = as_token_unknown; | |
1935 | unsigned short as_type; | |
1936 | unsigned long asno = 0; | |
1937 | struct aspath *aspath; | |
1938 | int needtype; | |
1939 | ||
1940 | aspath = aspath_new(); | |
1941 | ||
1942 | /* We start default type as AS_SEQUENCE. */ | |
1943 | as_type = AS_SEQUENCE; | |
1944 | needtype = 1; | |
1945 | ||
1946 | while ((str = aspath_gettoken(str, &token, &asno)) != NULL) { | |
1947 | switch (token) { | |
1948 | case as_token_asval: | |
1949 | if (needtype) { | |
1950 | aspath_segment_add(aspath, as_type); | |
1951 | needtype = 0; | |
1952 | } | |
1953 | aspath_as_add(aspath, asno); | |
1954 | break; | |
1955 | case as_token_set_start: | |
1956 | as_type = AS_SET; | |
1957 | aspath_segment_add(aspath, as_type); | |
1958 | needtype = 0; | |
1959 | break; | |
1960 | case as_token_set_end: | |
1961 | as_type = AS_SEQUENCE; | |
1962 | needtype = 1; | |
1963 | break; | |
1964 | case as_token_confed_seq_start: | |
1965 | as_type = AS_CONFED_SEQUENCE; | |
1966 | aspath_segment_add(aspath, as_type); | |
1967 | needtype = 0; | |
1968 | break; | |
1969 | case as_token_confed_seq_end: | |
1970 | as_type = AS_SEQUENCE; | |
1971 | needtype = 1; | |
1972 | break; | |
1973 | case as_token_confed_set_start: | |
1974 | as_type = AS_CONFED_SET; | |
1975 | aspath_segment_add(aspath, as_type); | |
1976 | needtype = 0; | |
1977 | break; | |
1978 | case as_token_confed_set_end: | |
1979 | as_type = AS_SEQUENCE; | |
1980 | needtype = 1; | |
1981 | break; | |
1982 | case as_token_unknown: | |
1983 | default: | |
1984 | aspath_free(aspath); | |
1985 | return NULL; | |
1986 | } | |
1987 | } | |
1988 | ||
1989 | aspath_make_str_count(aspath, false); | |
1990 | ||
1991 | return aspath; | |
1992 | } | |
1993 | ||
1994 | /* Make hash value by raw aspath data. */ | |
1995 | unsigned int aspath_key_make(void *p) | |
1996 | { | |
1997 | struct aspath *aspath = (struct aspath *)p; | |
1998 | unsigned int key = 0; | |
1999 | ||
2000 | if (!aspath->str) | |
2001 | aspath_str_update(aspath, false); | |
2002 | ||
2003 | key = jhash(aspath->str, aspath->str_len, 2334325); | |
2004 | ||
2005 | return key; | |
2006 | } | |
2007 | ||
2008 | /* If two aspath have same value then return 1 else return 0 */ | |
2009 | int aspath_cmp(const void *arg1, const void *arg2) | |
2010 | { | |
2011 | const struct assegment *seg1 = ((const struct aspath *)arg1)->segments; | |
2012 | const struct assegment *seg2 = ((const struct aspath *)arg2)->segments; | |
2013 | ||
2014 | while (seg1 || seg2) { | |
2015 | int i; | |
2016 | if ((!seg1 && seg2) || (seg1 && !seg2)) | |
2017 | return 0; | |
2018 | if (seg1->type != seg2->type) | |
2019 | return 0; | |
2020 | if (seg1->length != seg2->length) | |
2021 | return 0; | |
2022 | for (i = 0; i < seg1->length; i++) | |
2023 | if (seg1->as[i] != seg2->as[i]) | |
2024 | return 0; | |
2025 | seg1 = seg1->next; | |
2026 | seg2 = seg2->next; | |
2027 | } | |
2028 | return 1; | |
2029 | } | |
2030 | ||
2031 | /* AS path hash initialize. */ | |
2032 | void aspath_init(void) | |
2033 | { | |
2034 | ashash = hash_create_size(32768, aspath_key_make, aspath_cmp, | |
2035 | "BGP AS Path"); | |
2036 | } | |
2037 | ||
2038 | void aspath_finish(void) | |
2039 | { | |
2040 | hash_clean(ashash, (void (*)(void *))aspath_free); | |
2041 | hash_free(ashash); | |
2042 | ashash = NULL; | |
2043 | ||
2044 | if (snmp_stream) | |
2045 | stream_free(snmp_stream); | |
2046 | } | |
2047 | ||
2048 | /* return and as path value */ | |
2049 | const char *aspath_print(struct aspath *as) | |
2050 | { | |
2051 | return (as ? as->str : NULL); | |
2052 | } | |
2053 | ||
2054 | /* Printing functions */ | |
2055 | /* Feed the AS_PATH to the vty; the suffix string follows it only in case | |
2056 | * AS_PATH wasn't empty. | |
2057 | */ | |
2058 | void aspath_print_vty(struct vty *vty, const char *format, struct aspath *as, | |
2059 | const char *suffix) | |
2060 | { | |
2061 | assert(format); | |
2062 | vty_out(vty, format, as->str); | |
2063 | if (as->str_len && strlen(suffix)) | |
2064 | vty_out(vty, "%s", suffix); | |
2065 | } | |
2066 | ||
2067 | static void aspath_show_all_iterator(struct hash_backet *backet, | |
2068 | struct vty *vty) | |
2069 | { | |
2070 | struct aspath *as; | |
2071 | ||
2072 | as = (struct aspath *)backet->data; | |
2073 | ||
2074 | vty_out(vty, "[%p:%u] (%ld) ", (void *)backet, backet->key, as->refcnt); | |
2075 | vty_out(vty, "%s\n", as->str); | |
2076 | } | |
2077 | ||
2078 | /* Print all aspath and hash information. This function is used from | |
2079 | `show [ip] bgp paths' command. */ | |
2080 | void aspath_print_all_vty(struct vty *vty) | |
2081 | { | |
2082 | hash_iterate(ashash, (void (*)(struct hash_backet *, | |
2083 | void *))aspath_show_all_iterator, | |
2084 | vty); | |
2085 | } |