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1 | /* | |
2 | * Input matching routines for CLI backend. | |
3 | * | |
4 | * -- | |
5 | * Copyright (C) 2016 Cumulus Networks, Inc. | |
6 | * | |
7 | * This file is part of GNU Zebra. | |
8 | * | |
9 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation; either version 2, or (at your option) any | |
12 | * later version. | |
13 | * | |
14 | * GNU Zebra is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along | |
20 | * with this program; see the file COPYING; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | #include <zebra.h> | |
25 | ||
26 | #include "command_match.h" | |
27 | #include "memory.h" | |
28 | ||
29 | DEFINE_MTYPE_STATIC(LIB, CMD_MATCHSTACK, "Command Match Stack"); | |
30 | ||
31 | #ifdef TRACE_MATCHER | |
32 | #define TM 1 | |
33 | #else | |
34 | #define TM 0 | |
35 | #endif | |
36 | ||
37 | #define trace_matcher(...) \ | |
38 | do { \ | |
39 | if (TM) \ | |
40 | fprintf(stderr, __VA_ARGS__); \ | |
41 | } while (0); | |
42 | ||
43 | /* matcher helper prototypes */ | |
44 | static int add_nexthops(struct list *, struct graph_node *, | |
45 | struct graph_node **, size_t, bool); | |
46 | ||
47 | static enum matcher_rv command_match_r(struct graph_node *, vector, | |
48 | unsigned int, struct graph_node **, | |
49 | struct list **); | |
50 | ||
51 | static int score_precedence(enum cmd_token_type); | |
52 | ||
53 | static enum match_type min_match_level(enum cmd_token_type); | |
54 | ||
55 | static void del_arglist(struct list *); | |
56 | ||
57 | static struct cmd_token *disambiguate_tokens(struct cmd_token *, | |
58 | struct cmd_token *, char *); | |
59 | ||
60 | static struct list *disambiguate(struct list *, struct list *, vector, | |
61 | unsigned int); | |
62 | ||
63 | int compare_completions(const void *, const void *); | |
64 | ||
65 | /* token matcher prototypes */ | |
66 | static enum match_type match_token(struct cmd_token *, char *); | |
67 | ||
68 | static enum match_type match_ipv4(const char *); | |
69 | ||
70 | static enum match_type match_ipv4_prefix(const char *); | |
71 | ||
72 | static enum match_type match_ipv6_prefix(const char *, bool); | |
73 | ||
74 | static enum match_type match_range(struct cmd_token *, const char *); | |
75 | ||
76 | static enum match_type match_word(struct cmd_token *, const char *); | |
77 | ||
78 | static enum match_type match_variable(struct cmd_token *, const char *); | |
79 | ||
80 | static enum match_type match_mac(const char *, bool); | |
81 | ||
82 | static bool is_neg(vector vline, size_t idx) | |
83 | { | |
84 | if (idx >= vector_active(vline) || !vector_slot(vline, idx)) | |
85 | return false; | |
86 | return !strcmp(vector_slot(vline, idx), "no"); | |
87 | } | |
88 | ||
89 | enum matcher_rv command_match(struct graph *cmdgraph, vector vline, | |
90 | struct list **argv, const struct cmd_element **el) | |
91 | { | |
92 | struct graph_node *stack[CMD_ARGC_MAX]; | |
93 | enum matcher_rv status; | |
94 | *argv = NULL; | |
95 | ||
96 | // prepend a dummy token to match that pesky start node | |
97 | vector vvline = vector_init(vline->alloced + 1); | |
98 | vector_set_index(vvline, 0, XSTRDUP(MTYPE_TMP, "dummy")); | |
99 | memcpy(vvline->index + 1, vline->index, | |
100 | sizeof(void *) * vline->alloced); | |
101 | vvline->active = vline->active + 1; | |
102 | ||
103 | struct graph_node *start = vector_slot(cmdgraph->nodes, 0); | |
104 | status = command_match_r(start, vvline, 0, stack, argv); | |
105 | if (status == MATCHER_OK) { // successful match | |
106 | struct listnode *head = listhead(*argv); | |
107 | struct listnode *tail = listtail(*argv); | |
108 | ||
109 | assert(head); | |
110 | assert(tail); | |
111 | ||
112 | // delete dummy start node | |
113 | cmd_token_del((struct cmd_token *)head->data); | |
114 | list_delete_node(*argv, head); | |
115 | ||
116 | // get cmd_element out of list tail | |
117 | *el = listgetdata(tail); | |
118 | list_delete_node(*argv, tail); | |
119 | ||
120 | // now argv is an ordered list of cmd_token matching the user | |
121 | // input, with each cmd_token->arg holding the corresponding | |
122 | // input | |
123 | assert(*el); | |
124 | } else if (*argv) { | |
125 | del_arglist(*argv); | |
126 | *argv = NULL; | |
127 | } | |
128 | ||
129 | if (!*el) { | |
130 | trace_matcher("No match\n"); | |
131 | } else { | |
132 | trace_matcher("Matched command\n->string %s\n->desc %s\n", | |
133 | (*el)->string, (*el)->doc); | |
134 | } | |
135 | ||
136 | // free the leader token we alloc'd | |
137 | XFREE(MTYPE_TMP, vector_slot(vvline, 0)); | |
138 | // free vector | |
139 | vector_free(vvline); | |
140 | ||
141 | return status; | |
142 | } | |
143 | ||
144 | /** | |
145 | * Builds an argument list given a DFA and a matching input line. | |
146 | * | |
147 | * First the function determines if the node it is passed matches the first | |
148 | * token of input. If it does not, it returns NULL (MATCHER_NO_MATCH). If it | |
149 | * does match, then it saves the input token as the head of an argument list. | |
150 | * | |
151 | * The next step is to see if there is further input in the input line. If | |
152 | * there is not, the current node's children are searched to see if any of them | |
153 | * are leaves (type END_TKN). If this is the case, then the bottom of the | |
154 | * recursion stack has been reached, the leaf is pushed onto the argument list, | |
155 | * the current node is pushed, and the resulting argument list is | |
156 | * returned (MATCHER_OK). If it is not the case, NULL is returned, indicating | |
157 | * that there is no match for the input along this path (MATCHER_INCOMPLETE). | |
158 | * | |
159 | * If there is further input, then the function recurses on each of the current | |
160 | * node's children, passing them the input line minus the token that was just | |
161 | * matched. For each child, the return value of the recursive call is | |
162 | * inspected. If it is null, then there is no match for the input along the | |
163 | * subgraph headed by that child. If it is not null, then there is at least one | |
164 | * input match in that subgraph (more on this in a moment). | |
165 | * | |
166 | * If a recursive call on a child returns a non-null value, then it has matched | |
167 | * the input given it on the subgraph that starts with that child. However, due | |
168 | * to the flexibility of the grammar, it is sometimes the case that two or more | |
169 | * child graphs match the same input (two or more of the recursive calls have | |
170 | * non-NULL return values). This is not a valid state, since only one true | |
171 | * match is possible. In order to resolve this conflict, the function keeps a | |
172 | * reference to the child node that most specifically matches the input. This | |
173 | * is done by assigning each node type a precedence. If a child is found to | |
174 | * match the remaining input, then the precedence values of the current | |
175 | * best-matching child and this new match are compared. The node with higher | |
176 | * precedence is kept, and the other match is discarded. Due to the recursive | |
177 | * nature of this function, it is only necessary to compare the precedence of | |
178 | * immediate children, since all subsequent children will already have been | |
179 | * disambiguated in this way. | |
180 | * | |
181 | * In the event that two children are found to match with the same precedence, | |
182 | * then the input is ambiguous for the passed cmd_element and NULL is returned. | |
183 | * | |
184 | * @param[in] start the start node. | |
185 | * @param[in] vline the vectorized input line. | |
186 | * @param[in] n the index of the first input token. | |
187 | * @return A linked list of n elements. The first n-1 elements are pointers to | |
188 | * struct cmd_token and represent the sequence of tokens matched by the input. | |
189 | * The ->arg field of each token points to a copy of the input matched on it. | |
190 | * The final nth element is a pointer to struct cmd_element, which is the | |
191 | * command that was matched. | |
192 | * | |
193 | * If no match was found, the return value is NULL. | |
194 | */ | |
195 | static enum matcher_rv command_match_r(struct graph_node *start, vector vline, | |
196 | unsigned int n, | |
197 | struct graph_node **stack, | |
198 | struct list **currbest) | |
199 | { | |
200 | assert(n < vector_active(vline)); | |
201 | ||
202 | enum matcher_rv status = MATCHER_NO_MATCH; | |
203 | ||
204 | // get the minimum match level that can count as a full match | |
205 | struct cmd_token *copy, *token = start->data; | |
206 | enum match_type minmatch = min_match_level(token->type); | |
207 | ||
208 | /* check history/stack of tokens | |
209 | * this disallows matching the same one more than once if there is a | |
210 | * circle in the graph (used for keyword arguments) */ | |
211 | if (n == CMD_ARGC_MAX) | |
212 | return MATCHER_NO_MATCH; | |
213 | if (!token->allowrepeat) | |
214 | for (size_t s = 0; s < n; s++) | |
215 | if (stack[s] == start) | |
216 | return MATCHER_NO_MATCH; | |
217 | ||
218 | // get the current operating input token | |
219 | char *input_token = vector_slot(vline, n); | |
220 | ||
221 | #ifdef TRACE_MATCHER | |
222 | fprintf(stdout, "\"%-20s\" matches \"%-30s\" ? ", input_token, | |
223 | token->text); | |
224 | enum match_type mt = match_token(token, input_token); | |
225 | fprintf(stdout, "type: %d ", token->type); | |
226 | fprintf(stdout, "min: %d - ", minmatch); | |
227 | switch (mt) { | |
228 | case trivial_match: | |
229 | fprintf(stdout, "trivial_match "); | |
230 | break; | |
231 | case no_match: | |
232 | fprintf(stdout, "no_match "); | |
233 | break; | |
234 | case partly_match: | |
235 | fprintf(stdout, "partly_match "); | |
236 | break; | |
237 | case exact_match: | |
238 | fprintf(stdout, "exact_match "); | |
239 | break; | |
240 | } | |
241 | if (mt >= minmatch) | |
242 | fprintf(stdout, " MATCH"); | |
243 | fprintf(stdout, "\n"); | |
244 | #endif | |
245 | ||
246 | // if we don't match this node, die | |
247 | if (match_token(token, input_token) < minmatch) | |
248 | return MATCHER_NO_MATCH; | |
249 | ||
250 | stack[n] = start; | |
251 | ||
252 | // pointers for iterating linklist | |
253 | struct listnode *ln; | |
254 | struct graph_node *gn; | |
255 | ||
256 | // get all possible nexthops | |
257 | struct list *next = list_new(); | |
258 | add_nexthops(next, start, NULL, 0, is_neg(vline, 1)); | |
259 | ||
260 | // determine the best match | |
261 | for (ALL_LIST_ELEMENTS_RO(next, ln, gn)) { | |
262 | // if we've matched all input we're looking for END_TKN | |
263 | if (n + 1 == vector_active(vline)) { | |
264 | struct cmd_token *tok = gn->data; | |
265 | if (tok->type == END_TKN) { | |
266 | // if more than one END_TKN in the follow set | |
267 | if (*currbest) { | |
268 | status = MATCHER_AMBIGUOUS; | |
269 | break; | |
270 | } else { | |
271 | status = MATCHER_OK; | |
272 | } | |
273 | *currbest = list_new(); | |
274 | // node should have one child node with the | |
275 | // element | |
276 | struct graph_node *leaf = | |
277 | vector_slot(gn->to, 0); | |
278 | // last node in the list will hold the | |
279 | // cmd_element; this is important because | |
280 | // list_delete() expects that all nodes have | |
281 | // the same data type, so when deleting this | |
282 | // list the last node must be manually deleted | |
283 | struct cmd_element *el = leaf->data; | |
284 | listnode_add(*currbest, el); | |
285 | (*currbest)->del = | |
286 | (void (*)(void *)) & cmd_token_del; | |
287 | // do not break immediately; continue walking | |
288 | // through the follow set to ensure that there | |
289 | // is exactly one END_TKN | |
290 | } | |
291 | continue; | |
292 | } | |
293 | ||
294 | // else recurse on candidate child node | |
295 | struct list *result = NULL; | |
296 | enum matcher_rv rstat = | |
297 | command_match_r(gn, vline, n + 1, stack, &result); | |
298 | ||
299 | // save the best match | |
300 | if (result && *currbest) { | |
301 | // pick the best of two matches | |
302 | struct list *newbest = | |
303 | disambiguate(*currbest, result, vline, n + 1); | |
304 | ||
305 | // current best and result are ambiguous | |
306 | if (!newbest) | |
307 | status = MATCHER_AMBIGUOUS; | |
308 | // current best is still the best, but ambiguous | |
309 | else if (newbest == *currbest | |
310 | && status == MATCHER_AMBIGUOUS) | |
311 | status = MATCHER_AMBIGUOUS; | |
312 | // result is better, but also ambiguous | |
313 | else if (newbest == result | |
314 | && rstat == MATCHER_AMBIGUOUS) | |
315 | status = MATCHER_AMBIGUOUS; | |
316 | // one or the other is superior and not ambiguous | |
317 | else | |
318 | status = MATCHER_OK; | |
319 | ||
320 | // delete the unnecessary result | |
321 | struct list *todelete = | |
322 | ((newbest && newbest == result) ? *currbest | |
323 | : result); | |
324 | del_arglist(todelete); | |
325 | ||
326 | *currbest = newbest ? newbest : *currbest; | |
327 | } else if (result) { | |
328 | status = rstat; | |
329 | *currbest = result; | |
330 | } else if (!*currbest) { | |
331 | status = MAX(rstat, status); | |
332 | } | |
333 | } | |
334 | if (*currbest) { | |
335 | // copy token, set arg and prepend to currbest | |
336 | token = start->data; | |
337 | copy = cmd_token_dup(token); | |
338 | copy->arg = XSTRDUP(MTYPE_CMD_ARG, input_token); | |
339 | listnode_add_before(*currbest, (*currbest)->head, copy); | |
340 | } else if (n + 1 == vector_active(vline) && status == MATCHER_NO_MATCH) | |
341 | status = MATCHER_INCOMPLETE; | |
342 | ||
343 | // cleanup | |
344 | list_delete(&next); | |
345 | ||
346 | return status; | |
347 | } | |
348 | ||
349 | static void stack_del(void *val) | |
350 | { | |
351 | XFREE(MTYPE_CMD_MATCHSTACK, val); | |
352 | } | |
353 | ||
354 | enum matcher_rv command_complete(struct graph *graph, vector vline, | |
355 | struct list **completions) | |
356 | { | |
357 | // pointer to next input token to match | |
358 | char *input_token; | |
359 | bool neg = is_neg(vline, 0); | |
360 | ||
361 | struct list * | |
362 | current = | |
363 | list_new(), // current nodes to match input token against | |
364 | *next = list_new(); // possible next hops after current input | |
365 | // token | |
366 | current->del = next->del = stack_del; | |
367 | ||
368 | // pointers used for iterating lists | |
369 | struct graph_node **gstack, **newstack; | |
370 | struct listnode *node; | |
371 | ||
372 | // add all children of start node to list | |
373 | struct graph_node *start = vector_slot(graph->nodes, 0); | |
374 | add_nexthops(next, start, &start, 0, neg); | |
375 | ||
376 | unsigned int idx; | |
377 | for (idx = 0; idx < vector_active(vline) && next->count > 0; idx++) { | |
378 | list_delete(¤t); | |
379 | current = next; | |
380 | next = list_new(); | |
381 | next->del = stack_del; | |
382 | ||
383 | input_token = vector_slot(vline, idx); | |
384 | ||
385 | int exact_match_exists = 0; | |
386 | for (ALL_LIST_ELEMENTS_RO(current, node, gstack)) | |
387 | if (!exact_match_exists) | |
388 | exact_match_exists = | |
389 | (match_token(gstack[0]->data, | |
390 | input_token) | |
391 | == exact_match); | |
392 | else | |
393 | break; | |
394 | ||
395 | for (ALL_LIST_ELEMENTS_RO(current, node, gstack)) { | |
396 | struct cmd_token *token = gstack[0]->data; | |
397 | ||
398 | if (token->attr & CMD_ATTR_HIDDEN) | |
399 | continue; | |
400 | ||
401 | enum match_type minmatch = min_match_level(token->type); | |
402 | trace_matcher("\"%s\" matches \"%s\" (%d) ? ", | |
403 | input_token, token->text, token->type); | |
404 | ||
405 | unsigned int last_token = | |
406 | (vector_active(vline) - 1 == idx); | |
407 | enum match_type matchtype = | |
408 | match_token(token, input_token); | |
409 | switch (matchtype) { | |
410 | // occurs when last token is whitespace | |
411 | case trivial_match: | |
412 | trace_matcher("trivial_match\n"); | |
413 | assert(last_token); | |
414 | newstack = XMALLOC(MTYPE_CMD_MATCHSTACK, | |
415 | sizeof(struct graph_node *)); | |
416 | /* we're not recursing here, just the first | |
417 | * element is OK */ | |
418 | newstack[0] = gstack[0]; | |
419 | listnode_add(next, newstack); | |
420 | break; | |
421 | case partly_match: | |
422 | trace_matcher("trivial_match\n"); | |
423 | if (exact_match_exists && !last_token) | |
424 | break; | |
425 | /* fallthru */ | |
426 | case exact_match: | |
427 | trace_matcher("exact_match\n"); | |
428 | if (last_token) { | |
429 | newstack = XMALLOC( | |
430 | MTYPE_CMD_MATCHSTACK, | |
431 | sizeof(struct graph_node *)); | |
432 | /* same as above, not recursing on this | |
433 | */ | |
434 | newstack[0] = gstack[0]; | |
435 | listnode_add(next, newstack); | |
436 | } else if (matchtype >= minmatch) | |
437 | add_nexthops(next, gstack[0], gstack, | |
438 | idx + 1, neg); | |
439 | break; | |
440 | default: | |
441 | trace_matcher("no_match\n"); | |
442 | break; | |
443 | } | |
444 | } | |
445 | } | |
446 | ||
447 | /* Variable summary | |
448 | * ----------------------------------------------------------------- | |
449 | * token = last input token processed | |
450 | * idx = index in `command` of last token processed | |
451 | * current = set of all transitions from the previous input token | |
452 | * next = set of all nodes reachable from all nodes in `matched` | |
453 | */ | |
454 | ||
455 | enum matcher_rv mrv = idx == vector_active(vline) && next->count | |
456 | ? MATCHER_OK | |
457 | : MATCHER_NO_MATCH; | |
458 | ||
459 | *completions = NULL; | |
460 | if (!MATCHER_ERROR(mrv)) { | |
461 | // extract cmd_token into list | |
462 | *completions = list_new(); | |
463 | for (ALL_LIST_ELEMENTS_RO(next, node, gstack)) { | |
464 | listnode_add(*completions, gstack[0]->data); | |
465 | } | |
466 | } | |
467 | ||
468 | list_delete(¤t); | |
469 | list_delete(&next); | |
470 | ||
471 | return mrv; | |
472 | } | |
473 | ||
474 | /** | |
475 | * Adds all children that are reachable by one parser hop to the given list. | |
476 | * special tokens except END_TKN are treated as transparent. | |
477 | * | |
478 | * @param[in] list to add the nexthops to | |
479 | * @param[in] node to start calculating nexthops from | |
480 | * @param[in] stack listing previously visited nodes, if non-NULL. | |
481 | * @param[in] stackpos how many valid entries are in stack | |
482 | * @return the number of children added to the list | |
483 | * | |
484 | * NB: non-null "stack" means that new stacks will be added to "list" as | |
485 | * output, instead of direct node pointers! | |
486 | */ | |
487 | static int add_nexthops(struct list *list, struct graph_node *node, | |
488 | struct graph_node **stack, size_t stackpos, bool neg) | |
489 | { | |
490 | int added = 0; | |
491 | struct graph_node *child; | |
492 | struct graph_node **nextstack; | |
493 | for (unsigned int i = 0; i < vector_active(node->to); i++) { | |
494 | child = vector_slot(node->to, i); | |
495 | size_t j; | |
496 | struct cmd_token *token = child->data; | |
497 | if (!token->allowrepeat && stack) { | |
498 | for (j = 0; j < stackpos; j++) | |
499 | if (child == stack[j]) | |
500 | break; | |
501 | if (j != stackpos) | |
502 | continue; | |
503 | } | |
504 | ||
505 | if (token->type == NEG_ONLY_TKN && !neg) | |
506 | continue; | |
507 | ||
508 | if (token->type >= SPECIAL_TKN && token->type != END_TKN) { | |
509 | added += | |
510 | add_nexthops(list, child, stack, stackpos, neg); | |
511 | } else { | |
512 | if (stack) { | |
513 | nextstack = XMALLOC( | |
514 | MTYPE_CMD_MATCHSTACK, | |
515 | (stackpos + 1) | |
516 | * sizeof(struct graph_node *)); | |
517 | nextstack[0] = child; | |
518 | memcpy(nextstack + 1, stack, | |
519 | stackpos * sizeof(struct graph_node *)); | |
520 | ||
521 | listnode_add(list, nextstack); | |
522 | } else | |
523 | listnode_add(list, child); | |
524 | added++; | |
525 | } | |
526 | } | |
527 | ||
528 | return added; | |
529 | } | |
530 | ||
531 | /** | |
532 | * Determines the node types for which a partial match may count as a full | |
533 | * match. Enables command abbrevations. | |
534 | * | |
535 | * @param[in] type node type | |
536 | * @return minimum match level needed to for a token to fully match | |
537 | */ | |
538 | static enum match_type min_match_level(enum cmd_token_type type) | |
539 | { | |
540 | switch (type) { | |
541 | // anything matches a start node, for the sake of recursion | |
542 | case START_TKN: | |
543 | return no_match; | |
544 | // allowing words to partly match enables command abbreviation | |
545 | case WORD_TKN: | |
546 | return partly_match; | |
547 | default: | |
548 | return exact_match; | |
549 | } | |
550 | } | |
551 | ||
552 | /** | |
553 | * Assigns precedence scores to node types. | |
554 | * | |
555 | * @param[in] type node type to score | |
556 | * @return precedence score | |
557 | */ | |
558 | static int score_precedence(enum cmd_token_type type) | |
559 | { | |
560 | switch (type) { | |
561 | // some of these are mutually exclusive, so they share | |
562 | // the same precedence value | |
563 | case IPV4_TKN: | |
564 | case IPV4_PREFIX_TKN: | |
565 | case IPV6_TKN: | |
566 | case IPV6_PREFIX_TKN: | |
567 | case MAC_TKN: | |
568 | case MAC_PREFIX_TKN: | |
569 | case RANGE_TKN: | |
570 | return 2; | |
571 | case WORD_TKN: | |
572 | return 3; | |
573 | case VARIABLE_TKN: | |
574 | return 4; | |
575 | default: | |
576 | return 10; | |
577 | } | |
578 | } | |
579 | ||
580 | /** | |
581 | * Picks the better of two possible matches for a token. | |
582 | * | |
583 | * @param[in] first candidate node matching token | |
584 | * @param[in] second candidate node matching token | |
585 | * @param[in] token the token being matched | |
586 | * @return the best-matching node, or NULL if the two are entirely ambiguous | |
587 | */ | |
588 | static struct cmd_token *disambiguate_tokens(struct cmd_token *first, | |
589 | struct cmd_token *second, | |
590 | char *input_token) | |
591 | { | |
592 | // if the types are different, simply go off of type precedence | |
593 | if (first->type != second->type) { | |
594 | int firstprec = score_precedence(first->type); | |
595 | int secndprec = score_precedence(second->type); | |
596 | if (firstprec != secndprec) | |
597 | return firstprec < secndprec ? first : second; | |
598 | else | |
599 | return NULL; | |
600 | } | |
601 | ||
602 | // if they're the same, return the more exact match | |
603 | enum match_type fmtype = match_token(first, input_token); | |
604 | enum match_type smtype = match_token(second, input_token); | |
605 | if (fmtype != smtype) | |
606 | return fmtype > smtype ? first : second; | |
607 | ||
608 | return NULL; | |
609 | } | |
610 | ||
611 | /** | |
612 | * Picks the better of two possible matches for an input line. | |
613 | * | |
614 | * @param[in] first candidate list of cmd_token matching vline | |
615 | * @param[in] second candidate list of cmd_token matching vline | |
616 | * @param[in] vline the input line being matched | |
617 | * @param[in] n index into vline to start comparing at | |
618 | * @return the best-matching list, or NULL if the two are entirely ambiguous | |
619 | */ | |
620 | static struct list *disambiguate(struct list *first, struct list *second, | |
621 | vector vline, unsigned int n) | |
622 | { | |
623 | assert(first != NULL); | |
624 | assert(second != NULL); | |
625 | // doesn't make sense for these to be inequal length | |
626 | assert(first->count == second->count); | |
627 | assert(first->count == vector_active(vline) - n + 1); | |
628 | ||
629 | struct listnode *fnode = listhead_unchecked(first), | |
630 | *snode = listhead_unchecked(second); | |
631 | struct cmd_token *ftok = listgetdata(fnode), *stok = listgetdata(snode), | |
632 | *best = NULL; | |
633 | ||
634 | // compare each token, if one matches better use that one | |
635 | for (unsigned int i = n; i < vector_active(vline); i++) { | |
636 | char *token = vector_slot(vline, i); | |
637 | if ((best = disambiguate_tokens(ftok, stok, token))) | |
638 | return best == ftok ? first : second; | |
639 | fnode = listnextnode(fnode); | |
640 | snode = listnextnode(snode); | |
641 | ftok = listgetdata(fnode); | |
642 | stok = listgetdata(snode); | |
643 | } | |
644 | ||
645 | return NULL; | |
646 | } | |
647 | ||
648 | /* | |
649 | * Deletion function for arglist. | |
650 | * | |
651 | * Since list->del for arglists expects all listnode->data to hold cmd_token, | |
652 | * but arglists have cmd_element as the data for the tail, this function | |
653 | * manually deletes the tail before deleting the rest of the list as usual. | |
654 | * | |
655 | * The cmd_element at the end is *not* a copy. It is the one and only. | |
656 | * | |
657 | * @param list the arglist to delete | |
658 | */ | |
659 | static void del_arglist(struct list *list) | |
660 | { | |
661 | // manually delete last node | |
662 | struct listnode *tail = listtail(list); | |
663 | tail->data = NULL; | |
664 | list_delete_node(list, tail); | |
665 | ||
666 | // delete the rest of the list as usual | |
667 | list_delete(&list); | |
668 | } | |
669 | ||
670 | /*---------- token level matching functions ----------*/ | |
671 | ||
672 | static enum match_type match_token(struct cmd_token *token, char *input_token) | |
673 | { | |
674 | // nothing trivially matches everything | |
675 | if (!input_token) | |
676 | return trivial_match; | |
677 | ||
678 | switch (token->type) { | |
679 | case WORD_TKN: | |
680 | return match_word(token, input_token); | |
681 | case IPV4_TKN: | |
682 | return match_ipv4(input_token); | |
683 | case IPV4_PREFIX_TKN: | |
684 | return match_ipv4_prefix(input_token); | |
685 | case IPV6_TKN: | |
686 | return match_ipv6_prefix(input_token, false); | |
687 | case IPV6_PREFIX_TKN: | |
688 | return match_ipv6_prefix(input_token, true); | |
689 | case RANGE_TKN: | |
690 | return match_range(token, input_token); | |
691 | case VARIABLE_TKN: | |
692 | return match_variable(token, input_token); | |
693 | case MAC_TKN: | |
694 | return match_mac(input_token, false); | |
695 | case MAC_PREFIX_TKN: | |
696 | return match_mac(input_token, true); | |
697 | case END_TKN: | |
698 | default: | |
699 | return no_match; | |
700 | } | |
701 | } | |
702 | ||
703 | #define IPV4_ADDR_STR "0123456789." | |
704 | #define IPV4_PREFIX_STR "0123456789./" | |
705 | ||
706 | static enum match_type match_ipv4(const char *str) | |
707 | { | |
708 | const char *sp; | |
709 | int dots = 0, nums = 0; | |
710 | char buf[4]; | |
711 | ||
712 | for (;;) { | |
713 | memset(buf, 0, sizeof(buf)); | |
714 | sp = str; | |
715 | while (*str != '\0') { | |
716 | if (*str == '.') { | |
717 | if (dots >= 3) | |
718 | return no_match; | |
719 | ||
720 | if (*(str + 1) == '.') | |
721 | return no_match; | |
722 | ||
723 | if (*(str + 1) == '\0') | |
724 | return partly_match; | |
725 | ||
726 | dots++; | |
727 | break; | |
728 | } | |
729 | if (!isdigit((unsigned char)*str)) | |
730 | return no_match; | |
731 | ||
732 | str++; | |
733 | } | |
734 | ||
735 | if (str - sp > 3) | |
736 | return no_match; | |
737 | ||
738 | memcpy(buf, sp, str - sp); | |
739 | ||
740 | int v = atoi(buf); | |
741 | ||
742 | if (v > 255) | |
743 | return no_match; | |
744 | if (v > 0 && buf[0] == '0') | |
745 | return no_match; | |
746 | ||
747 | nums++; | |
748 | ||
749 | if (*str == '\0') | |
750 | break; | |
751 | ||
752 | str++; | |
753 | } | |
754 | ||
755 | if (nums < 4) | |
756 | return partly_match; | |
757 | ||
758 | return exact_match; | |
759 | } | |
760 | ||
761 | static enum match_type match_ipv4_prefix(const char *str) | |
762 | { | |
763 | const char *sp; | |
764 | int dots = 0; | |
765 | char buf[4]; | |
766 | ||
767 | for (;;) { | |
768 | memset(buf, 0, sizeof(buf)); | |
769 | sp = str; | |
770 | while (*str != '\0' && *str != '/') { | |
771 | if (*str == '.') { | |
772 | if (dots == 3) | |
773 | return no_match; | |
774 | ||
775 | if (*(str + 1) == '.' || *(str + 1) == '/') | |
776 | return no_match; | |
777 | ||
778 | if (*(str + 1) == '\0') | |
779 | return partly_match; | |
780 | ||
781 | dots++; | |
782 | break; | |
783 | } | |
784 | ||
785 | if (!isdigit((unsigned char)*str)) | |
786 | return no_match; | |
787 | ||
788 | str++; | |
789 | } | |
790 | ||
791 | if (str - sp > 3) | |
792 | return no_match; | |
793 | ||
794 | memcpy(buf, sp, str - sp); | |
795 | ||
796 | int v = atoi(buf); | |
797 | ||
798 | if (v > 255) | |
799 | return no_match; | |
800 | if (v > 0 && buf[0] == '0') | |
801 | return no_match; | |
802 | ||
803 | if (dots == 3) { | |
804 | if (*str == '/') { | |
805 | if (*(str + 1) == '\0') | |
806 | return partly_match; | |
807 | ||
808 | str++; | |
809 | break; | |
810 | } else if (*str == '\0') | |
811 | return partly_match; | |
812 | } | |
813 | ||
814 | if (*str == '\0') | |
815 | return partly_match; | |
816 | ||
817 | str++; | |
818 | } | |
819 | ||
820 | sp = str; | |
821 | while (*str != '\0') { | |
822 | if (!isdigit((unsigned char)*str)) | |
823 | return no_match; | |
824 | ||
825 | str++; | |
826 | } | |
827 | ||
828 | if (atoi(sp) > IPV4_MAX_BITLEN) | |
829 | return no_match; | |
830 | ||
831 | return exact_match; | |
832 | } | |
833 | ||
834 | ||
835 | #define IPV6_ADDR_STR "0123456789abcdefABCDEF:." | |
836 | #define IPV6_PREFIX_STR "0123456789abcdefABCDEF:./" | |
837 | #define STATE_START 1 | |
838 | #define STATE_COLON 2 | |
839 | #define STATE_DOUBLE 3 | |
840 | #define STATE_ADDR 4 | |
841 | #define STATE_DOT 5 | |
842 | #define STATE_SLASH 6 | |
843 | #define STATE_MASK 7 | |
844 | ||
845 | static enum match_type match_ipv6_prefix(const char *str, bool prefix) | |
846 | { | |
847 | int state = STATE_START; | |
848 | int colons = 0, nums = 0, double_colon = 0; | |
849 | int mask; | |
850 | const char *sp = NULL, *start = str; | |
851 | char *endptr = NULL; | |
852 | ||
853 | if (str == NULL) | |
854 | return partly_match; | |
855 | ||
856 | if (strspn(str, prefix ? IPV6_PREFIX_STR : IPV6_ADDR_STR) | |
857 | != strlen(str)) | |
858 | return no_match; | |
859 | ||
860 | while (*str != '\0' && state != STATE_MASK) { | |
861 | switch (state) { | |
862 | case STATE_START: | |
863 | if (*str == ':') { | |
864 | if (*(str + 1) != ':' && *(str + 1) != '\0') | |
865 | return no_match; | |
866 | colons--; | |
867 | state = STATE_COLON; | |
868 | } else { | |
869 | sp = str; | |
870 | state = STATE_ADDR; | |
871 | } | |
872 | ||
873 | continue; | |
874 | case STATE_COLON: | |
875 | colons++; | |
876 | if (*(str + 1) == '/') | |
877 | return no_match; | |
878 | else if (*(str + 1) == ':') | |
879 | state = STATE_DOUBLE; | |
880 | else { | |
881 | sp = str + 1; | |
882 | state = STATE_ADDR; | |
883 | } | |
884 | break; | |
885 | case STATE_DOUBLE: | |
886 | if (double_colon) | |
887 | return no_match; | |
888 | ||
889 | if (*(str + 1) == ':') | |
890 | return no_match; | |
891 | else { | |
892 | if (*(str + 1) != '\0' && *(str + 1) != '/') | |
893 | colons++; | |
894 | sp = str + 1; | |
895 | ||
896 | if (*(str + 1) == '/') | |
897 | state = STATE_SLASH; | |
898 | else | |
899 | state = STATE_ADDR; | |
900 | } | |
901 | ||
902 | double_colon++; | |
903 | nums += 1; | |
904 | break; | |
905 | case STATE_ADDR: | |
906 | if (*(str + 1) == ':' || *(str + 1) == '.' | |
907 | || *(str + 1) == '\0' || *(str + 1) == '/') { | |
908 | if (str - sp > 3) | |
909 | return no_match; | |
910 | ||
911 | for (; sp <= str; sp++) | |
912 | if (*sp == '/') | |
913 | return no_match; | |
914 | ||
915 | nums++; | |
916 | ||
917 | if (*(str + 1) == ':') | |
918 | state = STATE_COLON; | |
919 | else if (*(str + 1) == '.') { | |
920 | if (colons || double_colon) | |
921 | state = STATE_DOT; | |
922 | else | |
923 | return no_match; | |
924 | } else if (*(str + 1) == '/') | |
925 | state = STATE_SLASH; | |
926 | } | |
927 | break; | |
928 | case STATE_DOT: | |
929 | state = STATE_ADDR; | |
930 | break; | |
931 | case STATE_SLASH: | |
932 | if (*(str + 1) == '\0') | |
933 | return partly_match; | |
934 | ||
935 | state = STATE_MASK; | |
936 | break; | |
937 | default: | |
938 | break; | |
939 | } | |
940 | ||
941 | if (nums > 11) | |
942 | return no_match; | |
943 | ||
944 | if (colons > 7) | |
945 | return no_match; | |
946 | ||
947 | str++; | |
948 | } | |
949 | ||
950 | if (!prefix) { | |
951 | struct sockaddr_in6 sin6_dummy; | |
952 | int ret = inet_pton(AF_INET6, start, &sin6_dummy.sin6_addr); | |
953 | return ret == 1 ? exact_match : partly_match; | |
954 | } | |
955 | ||
956 | if (state < STATE_MASK) | |
957 | return partly_match; | |
958 | ||
959 | mask = strtol(str, &endptr, 10); | |
960 | if (*endptr != '\0') | |
961 | return no_match; | |
962 | ||
963 | if (mask < 0 || mask > IPV6_MAX_BITLEN) | |
964 | return no_match; | |
965 | ||
966 | return exact_match; | |
967 | } | |
968 | ||
969 | static enum match_type match_range(struct cmd_token *token, const char *str) | |
970 | { | |
971 | assert(token->type == RANGE_TKN); | |
972 | ||
973 | char *endptr = NULL; | |
974 | long long val; | |
975 | ||
976 | val = strtoll(str, &endptr, 10); | |
977 | if (*endptr != '\0') | |
978 | return no_match; | |
979 | ||
980 | if (val < token->min || val > token->max) | |
981 | return no_match; | |
982 | else | |
983 | return exact_match; | |
984 | } | |
985 | ||
986 | static enum match_type match_word(struct cmd_token *token, const char *word) | |
987 | { | |
988 | assert(token->type == WORD_TKN); | |
989 | ||
990 | // if the passed token is 0 length, partly match | |
991 | if (!strlen(word)) | |
992 | return partly_match; | |
993 | ||
994 | // if the passed token is strictly a prefix of the full word, partly | |
995 | // match | |
996 | if (strlen(word) < strlen(token->text)) | |
997 | return !strncmp(token->text, word, strlen(word)) ? partly_match | |
998 | : no_match; | |
999 | ||
1000 | // if they are the same length and exactly equal, exact match | |
1001 | else if (strlen(word) == strlen(token->text)) | |
1002 | return !strncmp(token->text, word, strlen(word)) ? exact_match | |
1003 | : no_match; | |
1004 | ||
1005 | return no_match; | |
1006 | } | |
1007 | ||
1008 | static enum match_type match_variable(struct cmd_token *token, const char *word) | |
1009 | { | |
1010 | assert(token->type == VARIABLE_TKN); | |
1011 | return exact_match; | |
1012 | } | |
1013 | ||
1014 | #define MAC_CHARS "ABCDEFabcdef0123456789:" | |
1015 | ||
1016 | static enum match_type match_mac(const char *word, bool prefix) | |
1017 | { | |
1018 | /* 6 2-digit hex numbers separated by 5 colons */ | |
1019 | size_t mac_explen = 6 * 2 + 5; | |
1020 | /* '/' + 2-digit integer */ | |
1021 | size_t mask_len = 1 + 2; | |
1022 | unsigned int i; | |
1023 | char *eptr; | |
1024 | unsigned int maskval; | |
1025 | ||
1026 | /* length check */ | |
1027 | if (strlen(word) > mac_explen + (prefix ? mask_len : 0)) | |
1028 | return no_match; | |
1029 | ||
1030 | /* address check */ | |
1031 | for (i = 0; i < mac_explen; i++) { | |
1032 | if (word[i] == '\0' || !strchr(MAC_CHARS, word[i])) | |
1033 | break; | |
1034 | if (((i + 1) % 3 == 0) != (word[i] == ':')) | |
1035 | return no_match; | |
1036 | } | |
1037 | ||
1038 | /* incomplete address */ | |
1039 | if (i < mac_explen && word[i] == '\0') | |
1040 | return partly_match; | |
1041 | else if (i < mac_explen) | |
1042 | return no_match; | |
1043 | ||
1044 | /* mask check */ | |
1045 | if (prefix && word[i] == '/') { | |
1046 | if (word[++i] == '\0') | |
1047 | return partly_match; | |
1048 | ||
1049 | maskval = strtoul(&word[i], &eptr, 10); | |
1050 | if (*eptr != '\0' || maskval > 48) | |
1051 | return no_match; | |
1052 | } else if (prefix && word[i] == '\0') { | |
1053 | return partly_match; | |
1054 | } else if (prefix) { | |
1055 | return no_match; | |
1056 | } | |
1057 | ||
1058 | return exact_match; | |
1059 | } |