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e0840f11 BP |
1 | /* |
2 | * Copyright (c) 2015 Nicira, Inc. | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | */ | |
16 | ||
17 | #include <config.h> | |
18 | #include "expr.h" | |
19 | #include "dynamic-string.h" | |
20 | #include "json.h" | |
21 | #include "lex.h" | |
22 | #include "match.h" | |
23 | #include "shash.h" | |
f386a8a7 | 24 | #include "simap.h" |
e0840f11 BP |
25 | #include "openvswitch/vlog.h" |
26 | ||
27 | VLOG_DEFINE_THIS_MODULE(expr); | |
28 | \f | |
29 | /* Returns the name of measurement level 'level'. */ | |
30 | const char * | |
31 | expr_level_to_string(enum expr_level level) | |
32 | { | |
33 | switch (level) { | |
34 | case EXPR_L_NOMINAL: return "nominal"; | |
35 | case EXPR_L_BOOLEAN: return "Boolean"; | |
36 | case EXPR_L_ORDINAL: return "ordinal"; | |
37 | default: OVS_NOT_REACHED(); | |
38 | } | |
39 | } | |
40 | \f | |
41 | /* Relational operators. */ | |
42 | ||
43 | /* Returns a string form of relational operator 'relop'. */ | |
44 | const char * | |
45 | expr_relop_to_string(enum expr_relop relop) | |
46 | { | |
47 | switch (relop) { | |
48 | case EXPR_R_EQ: return "=="; | |
49 | case EXPR_R_NE: return "!="; | |
50 | case EXPR_R_LT: return "<"; | |
51 | case EXPR_R_LE: return "<="; | |
52 | case EXPR_R_GT: return ">"; | |
53 | case EXPR_R_GE: return ">="; | |
54 | default: OVS_NOT_REACHED(); | |
55 | } | |
56 | } | |
57 | ||
58 | bool | |
59 | expr_relop_from_token(enum lex_type type, enum expr_relop *relop) | |
60 | { | |
61 | enum expr_relop r; | |
62 | ||
63 | switch ((int) type) { | |
64 | case LEX_T_EQ: r = EXPR_R_EQ; break; | |
65 | case LEX_T_NE: r = EXPR_R_NE; break; | |
66 | case LEX_T_LT: r = EXPR_R_LT; break; | |
67 | case LEX_T_LE: r = EXPR_R_LE; break; | |
68 | case LEX_T_GT: r = EXPR_R_GT; break; | |
69 | case LEX_T_GE: r = EXPR_R_GE; break; | |
70 | default: return false; | |
71 | } | |
72 | ||
73 | if (relop) { | |
74 | *relop = r; | |
75 | } | |
76 | return true; | |
77 | } | |
78 | ||
79 | /* Returns the relational operator that 'relop' becomes if you turn the | |
80 | * relation's operands around, e.g. EXPR_R_EQ does not change because "a == b" | |
81 | * and "b == a" are equivalent, but EXPR_R_LE becomes EXPR_R_GE because "a <= | |
82 | * b" is equivalent to "b >= a". */ | |
83 | static enum expr_relop | |
84 | expr_relop_turn(enum expr_relop relop) | |
85 | { | |
86 | switch (relop) { | |
87 | case EXPR_R_EQ: return EXPR_R_EQ; | |
88 | case EXPR_R_NE: return EXPR_R_NE; | |
89 | case EXPR_R_LT: return EXPR_R_GT; | |
90 | case EXPR_R_LE: return EXPR_R_GE; | |
91 | case EXPR_R_GT: return EXPR_R_LT; | |
92 | case EXPR_R_GE: return EXPR_R_LE; | |
93 | default: OVS_NOT_REACHED(); | |
94 | } | |
95 | } | |
96 | ||
97 | /* Returns the relational operator that is the opposite of 'relop'. */ | |
98 | static enum expr_relop | |
99 | expr_relop_invert(enum expr_relop relop) | |
100 | { | |
101 | switch (relop) { | |
102 | case EXPR_R_EQ: return EXPR_R_NE; | |
103 | case EXPR_R_NE: return EXPR_R_EQ; | |
104 | case EXPR_R_LT: return EXPR_R_GE; | |
105 | case EXPR_R_LE: return EXPR_R_GT; | |
106 | case EXPR_R_GT: return EXPR_R_LE; | |
107 | case EXPR_R_GE: return EXPR_R_LT; | |
108 | default: OVS_NOT_REACHED(); | |
109 | } | |
110 | } | |
111 | \f | |
112 | /* Constructing and manipulating expressions. */ | |
113 | ||
114 | /* Creates and returns a logical AND or OR expression (according to 'type', | |
115 | * which must be EXPR_T_AND or EXPR_T_OR) that initially has no | |
116 | * sub-expressions. (To satisfy the invariants for expressions, the caller | |
117 | * must add at least two sub-expressions whose types are different from | |
118 | * 'type'.) */ | |
119 | struct expr * | |
120 | expr_create_andor(enum expr_type type) | |
121 | { | |
122 | struct expr *e = xmalloc(sizeof *e); | |
123 | e->type = type; | |
124 | list_init(&e->andor); | |
125 | return e; | |
126 | } | |
127 | ||
128 | /* Returns a logical AND or OR expression (according to 'type', which must be | |
129 | * EXPR_T_AND or EXPR_T_OR) whose sub-expressions are 'a' and 'b', with some | |
130 | * flexibility: | |
131 | * | |
132 | * - If 'a' or 'b' is NULL, just returns the other one (which means that if | |
133 | * that other one is not of the given 'type', then the returned | |
134 | * expression is not either). | |
135 | * | |
136 | * - If 'a' or 'b', or both, have type 'type', then they are combined into | |
137 | * a single node that satisfies the invariants for expressions. */ | |
138 | struct expr * | |
139 | expr_combine(enum expr_type type, struct expr *a, struct expr *b) | |
140 | { | |
141 | if (!a) { | |
142 | return b; | |
143 | } else if (!b) { | |
144 | return a; | |
145 | } else if (a->type == type) { | |
146 | if (b->type == type) { | |
147 | list_splice(&a->andor, b->andor.next, &b->andor); | |
148 | free(b); | |
149 | } else { | |
150 | list_push_back(&a->andor, &b->node); | |
151 | } | |
152 | return a; | |
153 | } else if (b->type == type) { | |
154 | list_push_front(&b->andor, &a->node); | |
155 | return b; | |
156 | } else { | |
157 | struct expr *e = expr_create_andor(type); | |
158 | list_push_back(&e->andor, &a->node); | |
159 | list_push_back(&e->andor, &b->node); | |
160 | return e; | |
161 | } | |
162 | } | |
163 | ||
164 | static void | |
165 | expr_insert_andor(struct expr *andor, struct expr *before, struct expr *new) | |
166 | { | |
167 | if (new->type == andor->type) { | |
168 | if (andor->type == EXPR_T_AND) { | |
169 | /* Conjunction junction, what's your function? */ | |
170 | } | |
171 | list_splice(&before->node, new->andor.next, &new->andor); | |
172 | free(new); | |
173 | } else { | |
174 | list_insert(&before->node, &new->node); | |
175 | } | |
176 | } | |
177 | ||
178 | /* Returns an EXPR_T_BOOLEAN expression with value 'b'. */ | |
179 | struct expr * | |
180 | expr_create_boolean(bool b) | |
181 | { | |
182 | struct expr *e = xmalloc(sizeof *e); | |
183 | e->type = EXPR_T_BOOLEAN; | |
184 | e->boolean = b; | |
185 | return e; | |
186 | } | |
187 | ||
188 | static void | |
189 | expr_not(struct expr *expr) | |
190 | { | |
191 | struct expr *sub; | |
192 | ||
193 | switch (expr->type) { | |
194 | case EXPR_T_CMP: | |
195 | expr->cmp.relop = expr_relop_invert(expr->cmp.relop); | |
196 | break; | |
197 | ||
198 | case EXPR_T_AND: | |
199 | case EXPR_T_OR: | |
200 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
201 | expr_not(sub); | |
202 | } | |
203 | expr->type = expr->type == EXPR_T_AND ? EXPR_T_OR : EXPR_T_AND; | |
204 | break; | |
205 | ||
206 | case EXPR_T_BOOLEAN: | |
207 | expr->boolean = !expr->boolean; | |
208 | break; | |
209 | default: | |
210 | OVS_NOT_REACHED(); | |
211 | } | |
212 | } | |
213 | ||
214 | static struct expr * | |
215 | expr_fix_andor(struct expr *expr, bool short_circuit) | |
216 | { | |
217 | struct expr *sub, *next; | |
218 | ||
219 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
220 | if (sub->type == EXPR_T_BOOLEAN) { | |
221 | if (sub->boolean == short_circuit) { | |
222 | expr_destroy(expr); | |
223 | return expr_create_boolean(short_circuit); | |
224 | } else { | |
225 | list_remove(&sub->node); | |
226 | expr_destroy(sub); | |
227 | } | |
228 | } | |
229 | } | |
230 | ||
231 | if (list_is_short(&expr->andor)) { | |
232 | if (list_is_empty(&expr->andor)) { | |
233 | free(expr); | |
234 | return expr_create_boolean(!short_circuit); | |
235 | } else { | |
236 | sub = expr_from_node(list_front(&expr->andor)); | |
237 | free(expr); | |
238 | return sub; | |
239 | } | |
240 | } else { | |
241 | return expr; | |
242 | } | |
243 | } | |
244 | ||
245 | static struct expr * | |
246 | expr_fix(struct expr *expr) | |
247 | { | |
248 | switch (expr->type) { | |
249 | case EXPR_T_CMP: | |
250 | return expr; | |
251 | ||
252 | case EXPR_T_AND: | |
253 | return expr_fix_andor(expr, false); | |
254 | ||
255 | case EXPR_T_OR: | |
256 | return expr_fix_andor(expr, true); | |
257 | ||
258 | case EXPR_T_BOOLEAN: | |
259 | return expr; | |
260 | ||
261 | default: | |
262 | OVS_NOT_REACHED(); | |
263 | } | |
264 | } | |
265 | \f | |
266 | /* Formatting. */ | |
267 | ||
268 | static void | |
269 | find_bitwise_range(const union mf_subvalue *sv, int width, | |
270 | int *startp, int *n_bitsp) | |
271 | { | |
272 | unsigned int start = bitwise_scan(sv, sizeof *sv, true, 0, width); | |
273 | if (start < width) { | |
274 | unsigned int end = bitwise_scan(sv, sizeof *sv, false, start, width); | |
275 | if (end >= width | |
276 | || bitwise_scan(sv, sizeof *sv, true, end, width) >= width) { | |
277 | *startp = start; | |
278 | *n_bitsp = end - start; | |
279 | return; | |
280 | } | |
281 | } | |
282 | *startp = *n_bitsp = 0; | |
283 | } | |
284 | ||
285 | static void | |
286 | expr_format_string(const char *s, struct ds *ds) | |
287 | { | |
288 | struct json json = { | |
289 | .type = JSON_STRING, | |
290 | .u.string = CONST_CAST(char *, s), | |
291 | }; | |
292 | json_to_ds(&json, 0, ds); | |
293 | } | |
294 | ||
295 | static void | |
296 | expr_format_cmp(const struct expr *e, struct ds *s) | |
297 | { | |
298 | /* The common case is numerical comparisons. | |
299 | * Handle string comparisons as a special case. */ | |
300 | if (!e->cmp.symbol->width) { | |
301 | ds_put_format(s, "%s %s ", e->cmp.symbol->name, | |
302 | expr_relop_to_string(e->cmp.relop)); | |
303 | expr_format_string(e->cmp.string, s); | |
304 | return; | |
305 | } | |
306 | ||
307 | int ofs, n; | |
308 | find_bitwise_range(&e->cmp.mask, e->cmp.symbol->width, &ofs, &n); | |
309 | if (n == 1 && (e->cmp.relop == EXPR_R_EQ || e->cmp.relop == EXPR_R_NE)) { | |
310 | bool positive; | |
311 | ||
312 | positive = bitwise_get_bit(&e->cmp.value, sizeof e->cmp.value, ofs); | |
313 | positive ^= e->cmp.relop == EXPR_R_NE; | |
314 | if (!positive) { | |
315 | ds_put_char(s, '!'); | |
316 | } | |
317 | ds_put_cstr(s, e->cmp.symbol->name); | |
318 | if (e->cmp.symbol->width > 1) { | |
319 | ds_put_format(s, "[%d]", ofs); | |
320 | } | |
321 | return; | |
322 | } | |
323 | ||
324 | ds_put_cstr(s, e->cmp.symbol->name); | |
325 | if (n > 0 && n < e->cmp.symbol->width) { | |
326 | if (n > 1) { | |
327 | ds_put_format(s, "[%d..%d]", ofs, ofs + n - 1); | |
328 | } else { | |
329 | ds_put_format(s, "[%d]", ofs); | |
330 | } | |
331 | } | |
332 | ||
333 | ds_put_format(s, " %s ", expr_relop_to_string(e->cmp.relop)); | |
334 | ||
335 | if (n) { | |
336 | union mf_subvalue value; | |
337 | ||
338 | memset(&value, 0, sizeof value); | |
339 | bitwise_copy(&e->cmp.value, sizeof e->cmp.value, ofs, | |
340 | &value, sizeof value, 0, | |
341 | n); | |
342 | mf_format_subvalue(&value, s); | |
343 | } else { | |
344 | mf_format_subvalue(&e->cmp.value, s); | |
345 | ds_put_char(s, '/'); | |
346 | mf_format_subvalue(&e->cmp.mask, s); | |
347 | } | |
348 | } | |
349 | ||
350 | static void | |
351 | expr_format_andor(const struct expr *e, const char *op, struct ds *s) | |
352 | { | |
353 | struct expr *sub; | |
354 | int i = 0; | |
355 | ||
356 | LIST_FOR_EACH (sub, node, &e->andor) { | |
357 | if (i++) { | |
358 | ds_put_format(s, " %s ", op); | |
359 | } | |
360 | ||
361 | if (sub->type == EXPR_T_AND || sub->type == EXPR_T_OR) { | |
362 | ds_put_char(s, '('); | |
363 | expr_format(sub, s); | |
364 | ds_put_char(s, ')'); | |
365 | } else { | |
366 | expr_format(sub, s); | |
367 | } | |
368 | } | |
369 | } | |
370 | ||
371 | /* Appends a string form of 'e' to 's'. The string form is acceptable for | |
372 | * parsing back into an equivalent expression. */ | |
373 | void | |
374 | expr_format(const struct expr *e, struct ds *s) | |
375 | { | |
376 | switch (e->type) { | |
377 | case EXPR_T_CMP: | |
378 | expr_format_cmp(e, s); | |
379 | break; | |
380 | ||
381 | case EXPR_T_AND: | |
382 | expr_format_andor(e, "&&", s); | |
383 | break; | |
384 | ||
385 | case EXPR_T_OR: | |
386 | expr_format_andor(e, "||", s); | |
387 | break; | |
388 | ||
389 | case EXPR_T_BOOLEAN: | |
390 | ds_put_char(s, e->boolean ? '1' : '0'); | |
391 | break; | |
392 | } | |
393 | } | |
394 | ||
395 | /* Prints a string form of 'e' on stdout, followed by a new-line. */ | |
396 | void | |
397 | expr_print(const struct expr *e) | |
398 | { | |
399 | struct ds output; | |
400 | ||
401 | ds_init(&output); | |
402 | expr_format(e, &output); | |
403 | puts(ds_cstr(&output)); | |
404 | ds_destroy(&output); | |
405 | } | |
406 | \f | |
407 | /* Parsing. */ | |
408 | ||
409 | /* Type of a "union expr_constant" or "struct expr_constant_set". */ | |
410 | enum expr_constant_type { | |
411 | EXPR_C_INTEGER, | |
412 | EXPR_C_STRING | |
413 | }; | |
414 | ||
415 | /* A string or integer constant (one must know which from context). */ | |
416 | union expr_constant { | |
417 | /* Integer constant. | |
418 | * | |
419 | * The width of a constant isn't always clear, e.g. if you write "1", | |
420 | * there's no way to tell whether you mean for that to be a 1-bit constant | |
421 | * or a 128-bit constant or somewhere in between. */ | |
422 | struct { | |
423 | union mf_subvalue value; | |
424 | union mf_subvalue mask; /* Only initialized if 'masked'. */ | |
425 | bool masked; | |
426 | ||
427 | enum lex_format format; /* From the constant's lex_token. */ | |
428 | }; | |
429 | ||
430 | /* Null-terminated string constant. */ | |
431 | char *string; | |
432 | }; | |
433 | ||
434 | /* A collection of "union expr_constant"s of the same type. */ | |
435 | struct expr_constant_set { | |
436 | union expr_constant *values; /* Constants. */ | |
437 | size_t n_values; /* Number of constants. */ | |
438 | enum expr_constant_type type; /* Type of the constants. */ | |
439 | bool in_curlies; /* Whether the constants were in {}. */ | |
440 | }; | |
441 | ||
442 | /* A reference to a symbol or a subfield of a symbol. | |
443 | * | |
444 | * For string fields, ofs and n_bits are 0. */ | |
445 | struct expr_field { | |
446 | const struct expr_symbol *symbol; /* The symbol. */ | |
447 | int ofs; /* Starting bit offset. */ | |
448 | int n_bits; /* Number of bits. */ | |
449 | }; | |
450 | ||
451 | /* Context maintained during expr_parse(). */ | |
452 | struct expr_context { | |
453 | struct lexer *lexer; /* Lexer for pulling more tokens. */ | |
454 | const struct shash *symtab; /* Symbol table. */ | |
455 | char *error; /* Error, if any, otherwise NULL. */ | |
456 | bool not; /* True inside odd number of NOT operators. */ | |
457 | }; | |
458 | ||
459 | struct expr *expr_parse__(struct expr_context *); | |
460 | static void expr_not(struct expr *); | |
461 | static void expr_constant_set_destroy(struct expr_constant_set *); | |
462 | static bool parse_field(struct expr_context *, struct expr_field *); | |
463 | ||
464 | static bool | |
465 | expr_error_handle_common(struct expr_context *ctx) | |
466 | { | |
467 | if (ctx->error) { | |
468 | /* Already have an error, suppress this one since the cascade seems | |
469 | * unlikely to be useful. */ | |
470 | return true; | |
471 | } else if (ctx->lexer->token.type == LEX_T_ERROR) { | |
472 | /* The lexer signaled an error. Nothing at the expression level | |
473 | * accepts an error token, so we'll inevitably end up here with some | |
474 | * meaningless parse error. Report the lexical error instead. */ | |
475 | ctx->error = xstrdup(ctx->lexer->token.s); | |
476 | return true; | |
477 | } else { | |
478 | return false; | |
479 | } | |
480 | } | |
481 | ||
482 | static void OVS_PRINTF_FORMAT(2, 3) | |
483 | expr_error(struct expr_context *ctx, const char *message, ...) | |
484 | { | |
485 | if (expr_error_handle_common(ctx)) { | |
486 | return; | |
487 | } | |
488 | ||
489 | va_list args; | |
490 | va_start(args, message); | |
491 | ctx->error = xvasprintf(message, args); | |
492 | va_end(args); | |
493 | } | |
494 | ||
495 | static void OVS_PRINTF_FORMAT(2, 3) | |
496 | expr_syntax_error(struct expr_context *ctx, const char *message, ...) | |
497 | { | |
498 | if (expr_error_handle_common(ctx)) { | |
499 | return; | |
500 | } | |
501 | ||
502 | struct ds s; | |
503 | ||
504 | ds_init(&s); | |
505 | ds_put_cstr(&s, "Syntax error "); | |
506 | if (ctx->lexer->token.type == LEX_T_END) { | |
507 | ds_put_cstr(&s, "at end of input "); | |
508 | } else if (ctx->lexer->start) { | |
509 | ds_put_format(&s, "at `%.*s' ", | |
510 | (int) (ctx->lexer->input - ctx->lexer->start), | |
511 | ctx->lexer->start); | |
512 | } | |
513 | ||
514 | va_list args; | |
515 | va_start(args, message); | |
516 | ds_put_format_valist(&s, message, args); | |
517 | va_end(args); | |
518 | ||
519 | ctx->error = ds_steal_cstr(&s); | |
520 | } | |
521 | ||
522 | static struct expr * | |
523 | make_cmp__(const struct expr_field *f, enum expr_relop r, | |
524 | const union expr_constant *c) | |
525 | { | |
526 | struct expr *e = xzalloc(sizeof *e); | |
527 | e->type = EXPR_T_CMP; | |
528 | e->cmp.symbol = f->symbol; | |
529 | e->cmp.relop = r; | |
530 | if (f->symbol->width) { | |
531 | bitwise_copy(&c->value, sizeof c->value, 0, | |
532 | &e->cmp.value, sizeof e->cmp.value, f->ofs, | |
533 | f->n_bits); | |
534 | if (c->masked) { | |
535 | bitwise_copy(&c->mask, sizeof c->mask, 0, | |
536 | &e->cmp.mask, sizeof e->cmp.mask, f->ofs, | |
537 | f->n_bits); | |
538 | } else { | |
539 | bitwise_one(&e->cmp.mask, sizeof e->cmp.mask, f->ofs, | |
540 | f->n_bits); | |
541 | } | |
542 | } else { | |
543 | e->cmp.string = xstrdup(c->string); | |
544 | } | |
545 | return e; | |
546 | } | |
547 | ||
548 | /* Returns the minimum reasonable width for integer constant 'c'. */ | |
549 | static int | |
550 | expr_constant_width(const union expr_constant *c) | |
551 | { | |
552 | if (c->masked) { | |
553 | return mf_subvalue_width(&c->mask); | |
554 | } | |
555 | ||
556 | switch (c->format) { | |
557 | case LEX_F_DECIMAL: | |
558 | case LEX_F_HEXADECIMAL: | |
559 | return mf_subvalue_width(&c->value); | |
560 | ||
561 | case LEX_F_IPV4: | |
562 | return 32; | |
563 | ||
564 | case LEX_F_IPV6: | |
565 | return 128; | |
566 | ||
567 | case LEX_F_ETHERNET: | |
568 | return 48; | |
569 | ||
570 | default: | |
571 | OVS_NOT_REACHED(); | |
572 | } | |
573 | } | |
574 | ||
575 | static struct expr * | |
576 | make_cmp(struct expr_context *ctx, | |
577 | const struct expr_field *f, enum expr_relop r, | |
578 | struct expr_constant_set *cs) | |
579 | { | |
580 | struct expr *e = NULL; | |
581 | ||
582 | if (cs->type != (f->symbol->width ? EXPR_C_INTEGER : EXPR_C_STRING)) { | |
583 | expr_error(ctx, "Can't compare %s field %s to %s constant.", | |
584 | f->symbol->width ? "integer" : "string", | |
585 | f->symbol->name, | |
586 | cs->type == EXPR_C_INTEGER ? "integer" : "string"); | |
587 | goto exit; | |
588 | } | |
589 | ||
590 | if (r != EXPR_R_EQ && r != EXPR_R_NE) { | |
591 | if (cs->in_curlies) { | |
592 | expr_error(ctx, "Only == and != operators may be used " | |
593 | "with value sets."); | |
594 | goto exit; | |
595 | } | |
596 | if (f->symbol->level == EXPR_L_NOMINAL || | |
597 | f->symbol->level == EXPR_L_BOOLEAN) { | |
598 | expr_error(ctx, "Only == and != operators may be used " | |
599 | "with %s field %s.", | |
600 | expr_level_to_string(f->symbol->level), | |
601 | f->symbol->name); | |
602 | goto exit; | |
603 | } | |
604 | if (cs->values[0].masked) { | |
605 | expr_error(ctx, "Only == and != operators may be used with " | |
606 | "masked constants. Consider using subfields instead " | |
607 | "(e.g. eth.src[0..15] > 0x1111 in place of " | |
608 | "eth.src > 00:00:00:00:11:11/00:00:00:00:ff:ff)."); | |
609 | goto exit; | |
610 | } | |
611 | } | |
612 | ||
613 | if (f->symbol->level == EXPR_L_NOMINAL) { | |
614 | if (f->symbol->expansion) { | |
615 | for (size_t i = 0; i < cs->n_values; i++) { | |
616 | const union mf_subvalue *value = &cs->values[i].value; | |
617 | bool positive = (value->integer & htonll(1)) != 0; | |
618 | positive ^= r == EXPR_R_NE; | |
619 | positive ^= ctx->not; | |
620 | if (!positive) { | |
621 | const char *name = f->symbol->name; | |
622 | expr_error(ctx, "Nominal predicate %s may only be tested " | |
623 | "positively, e.g. `%s' or `%s == 1' but not " | |
624 | "`!%s' or `%s == 0'.", | |
625 | name, name, name, name, name); | |
626 | goto exit; | |
627 | } | |
628 | } | |
629 | } else if (r != (ctx->not ? EXPR_R_NE : EXPR_R_EQ)) { | |
630 | expr_error(ctx, "Nominal field %s may only be tested for " | |
631 | "equality (taking enclosing `!' operators into " | |
632 | "account).", f->symbol->name); | |
633 | goto exit; | |
634 | } | |
635 | } | |
636 | ||
637 | if (f->symbol->width) { | |
638 | for (size_t i = 0; i < cs->n_values; i++) { | |
639 | int w = expr_constant_width(&cs->values[i]); | |
640 | if (w > f->symbol->width) { | |
641 | expr_error(ctx, "Cannot compare %d-bit constant against " | |
642 | "%d-bit field %s.", | |
643 | w, f->symbol->width, f->symbol->name); | |
644 | goto exit; | |
645 | } | |
646 | } | |
647 | } | |
648 | ||
649 | e = make_cmp__(f, r, &cs->values[0]); | |
650 | for (size_t i = 1; i < cs->n_values; i++) { | |
651 | e = expr_combine(r == EXPR_R_EQ ? EXPR_T_OR : EXPR_T_AND, | |
652 | e, make_cmp__(f, r, &cs->values[i])); | |
653 | } | |
654 | exit: | |
655 | expr_constant_set_destroy(cs); | |
656 | return e; | |
657 | } | |
658 | ||
659 | static bool | |
660 | expr_get_int(struct expr_context *ctx, int *value) | |
661 | { | |
662 | if (ctx->lexer->token.type == LEX_T_INTEGER | |
663 | && ctx->lexer->token.format == LEX_F_DECIMAL | |
664 | && ntohll(ctx->lexer->token.value.integer) <= INT_MAX) { | |
665 | *value = ntohll(ctx->lexer->token.value.integer); | |
666 | lexer_get(ctx->lexer); | |
667 | return true; | |
668 | } else { | |
669 | expr_syntax_error(ctx, "expecting small integer."); | |
670 | return false; | |
671 | } | |
672 | } | |
673 | ||
674 | static bool | |
675 | parse_field(struct expr_context *ctx, struct expr_field *f) | |
676 | { | |
677 | const struct expr_symbol *symbol; | |
678 | ||
679 | if (ctx->lexer->token.type != LEX_T_ID) { | |
680 | expr_syntax_error(ctx, "expecting field name."); | |
681 | return false; | |
682 | } | |
683 | ||
684 | symbol = shash_find_data(ctx->symtab, ctx->lexer->token.s); | |
685 | if (!symbol) { | |
686 | expr_syntax_error(ctx, "expecting field name."); | |
687 | return false; | |
688 | } | |
689 | lexer_get(ctx->lexer); | |
690 | ||
691 | f->symbol = symbol; | |
692 | if (lexer_match(ctx->lexer, LEX_T_LSQUARE)) { | |
693 | int low, high; | |
694 | ||
695 | if (!symbol->width) { | |
696 | expr_error(ctx, "Cannot select subfield of string field %s.", | |
697 | symbol->name); | |
698 | return false; | |
699 | } | |
700 | ||
701 | if (!expr_get_int(ctx, &low)) { | |
702 | return false; | |
703 | } | |
704 | if (lexer_match(ctx->lexer, LEX_T_ELLIPSIS)) { | |
705 | if (!expr_get_int(ctx, &high)) { | |
706 | return false; | |
707 | } | |
708 | } else { | |
709 | high = low; | |
710 | } | |
711 | ||
712 | if (!lexer_match(ctx->lexer, LEX_T_RSQUARE)) { | |
713 | expr_syntax_error(ctx, "expecting `]'."); | |
714 | return false; | |
715 | } | |
716 | ||
717 | if (low > high) { | |
718 | expr_error(ctx, "Invalid bit range %d to %d.", low, high); | |
719 | return false; | |
720 | } else if (high >= symbol->width) { | |
721 | expr_error(ctx, "Cannot select bits %d to %d of %d-bit field %s.", | |
722 | low, high, symbol->width, symbol->name); | |
723 | return false; | |
724 | } else if (symbol->level == EXPR_L_NOMINAL | |
725 | && (low != 0 || high != symbol->width - 1)) { | |
726 | expr_error(ctx, "Cannot select subfield of nominal field %s.", | |
727 | symbol->name); | |
728 | return false; | |
729 | } | |
730 | ||
731 | f->ofs = low; | |
732 | f->n_bits = high - low + 1; | |
733 | } else { | |
734 | f->ofs = 0; | |
735 | f->n_bits = symbol->width; | |
736 | } | |
737 | ||
738 | return true; | |
739 | } | |
740 | ||
741 | static bool | |
742 | parse_relop(struct expr_context *ctx, enum expr_relop *relop) | |
743 | { | |
744 | if (expr_relop_from_token(ctx->lexer->token.type, relop)) { | |
745 | lexer_get(ctx->lexer); | |
746 | return true; | |
747 | } else { | |
748 | expr_syntax_error(ctx, "expecting relational operator."); | |
749 | return false; | |
750 | } | |
751 | } | |
752 | ||
753 | static bool | |
754 | assign_constant_set_type(struct expr_context *ctx, | |
755 | struct expr_constant_set *cs, | |
756 | enum expr_constant_type type) | |
757 | { | |
758 | if (!cs->n_values || cs->type == type) { | |
759 | cs->type = type; | |
760 | return true; | |
761 | } else { | |
762 | expr_syntax_error(ctx, "expecting %s.", | |
763 | cs->type == EXPR_C_INTEGER ? "integer" : "string"); | |
764 | return false; | |
765 | } | |
766 | } | |
767 | ||
768 | static bool | |
769 | parse_constant(struct expr_context *ctx, struct expr_constant_set *cs, | |
770 | size_t *allocated_values) | |
771 | { | |
772 | if (cs->n_values >= *allocated_values) { | |
773 | cs->values = x2nrealloc(cs->values, allocated_values, | |
774 | sizeof *cs->values); | |
775 | } | |
776 | ||
777 | if (ctx->lexer->token.type == LEX_T_STRING) { | |
778 | if (!assign_constant_set_type(ctx, cs, EXPR_C_STRING)) { | |
779 | return false; | |
780 | } | |
781 | cs->values[cs->n_values++].string = xstrdup(ctx->lexer->token.s); | |
782 | lexer_get(ctx->lexer); | |
783 | return true; | |
784 | } else if (ctx->lexer->token.type == LEX_T_INTEGER || | |
785 | ctx->lexer->token.type == LEX_T_MASKED_INTEGER) { | |
786 | if (!assign_constant_set_type(ctx, cs, EXPR_C_INTEGER)) { | |
787 | return false; | |
788 | } | |
789 | ||
790 | union expr_constant *c = &cs->values[cs->n_values++]; | |
791 | c->value = ctx->lexer->token.value; | |
792 | c->format = ctx->lexer->token.format; | |
793 | c->masked = ctx->lexer->token.type == LEX_T_MASKED_INTEGER; | |
794 | if (c->masked) { | |
795 | c->mask = ctx->lexer->token.mask; | |
796 | } | |
797 | lexer_get(ctx->lexer); | |
798 | return true; | |
799 | } else { | |
800 | expr_syntax_error(ctx, "expecting constant."); | |
801 | return false; | |
802 | } | |
803 | } | |
804 | ||
805 | /* Parses a single or {}-enclosed set of integer or string constants into 'cs', | |
806 | * which the caller need not have initialized. Returns true on success, in | |
807 | * which case the caller owns 'cs', false on failure, in which case 'cs' is | |
808 | * indeterminate. */ | |
809 | static bool | |
810 | parse_constant_set(struct expr_context *ctx, struct expr_constant_set *cs) | |
811 | { | |
812 | size_t allocated_values = 0; | |
813 | bool ok; | |
814 | ||
815 | memset(cs, 0, sizeof *cs); | |
816 | if (lexer_match(ctx->lexer, LEX_T_LCURLY)) { | |
817 | ok = true; | |
818 | cs->in_curlies = true; | |
819 | do { | |
820 | if (!parse_constant(ctx, cs, &allocated_values)) { | |
821 | ok = false; | |
822 | break; | |
823 | } | |
824 | lexer_match(ctx->lexer, LEX_T_COMMA); | |
825 | } while (!lexer_match(ctx->lexer, LEX_T_RCURLY)); | |
826 | } else { | |
827 | ok = parse_constant(ctx, cs, &allocated_values); | |
828 | } | |
829 | if (!ok) { | |
830 | expr_constant_set_destroy(cs); | |
831 | } | |
832 | return ok; | |
833 | } | |
834 | ||
835 | static void | |
836 | expr_constant_set_destroy(struct expr_constant_set *cs) | |
837 | { | |
838 | if (cs) { | |
839 | if (cs->type == EXPR_C_STRING) { | |
840 | for (size_t i = 0; i < cs->n_values; i++) { | |
841 | free(cs->values[i].string); | |
842 | } | |
843 | } | |
844 | free(cs->values); | |
845 | } | |
846 | } | |
847 | ||
848 | static struct expr * | |
849 | expr_parse_primary(struct expr_context *ctx, bool *atomic) | |
850 | { | |
851 | *atomic = false; | |
852 | if (lexer_match(ctx->lexer, LEX_T_LPAREN)) { | |
853 | struct expr *e = expr_parse__(ctx); | |
854 | if (!lexer_match(ctx->lexer, LEX_T_RPAREN)) { | |
855 | expr_destroy(e); | |
856 | expr_syntax_error(ctx, "expecting `)'."); | |
857 | return NULL; | |
858 | } | |
859 | *atomic = true; | |
860 | return e; | |
861 | } | |
862 | ||
863 | if (ctx->lexer->token.type == LEX_T_ID) { | |
864 | struct expr_field f; | |
865 | enum expr_relop r; | |
866 | struct expr_constant_set c; | |
867 | ||
868 | if (!parse_field(ctx, &f)) { | |
869 | return NULL; | |
870 | } | |
871 | ||
872 | if (!expr_relop_from_token(ctx->lexer->token.type, &r)) { | |
873 | if (f.n_bits > 1 && !ctx->not) { | |
874 | expr_error(ctx, "Explicit `!= 0' is required for inequality " | |
875 | "test of multibit field against 0."); | |
876 | return NULL; | |
877 | } | |
878 | ||
879 | *atomic = true; | |
880 | ||
881 | union expr_constant *cst = xzalloc(sizeof *cst); | |
882 | cst->format = LEX_F_HEXADECIMAL; | |
883 | cst->masked = false; | |
884 | ||
885 | c.type = EXPR_C_INTEGER; | |
886 | c.values = cst; | |
887 | c.n_values = 1; | |
888 | c.in_curlies = false; | |
889 | return make_cmp(ctx, &f, EXPR_R_NE, &c); | |
890 | } else if (parse_relop(ctx, &r) && parse_constant_set(ctx, &c)) { | |
891 | return make_cmp(ctx, &f, r, &c); | |
892 | } else { | |
893 | return NULL; | |
894 | } | |
895 | } else { | |
896 | struct expr_constant_set c1; | |
897 | if (!parse_constant_set(ctx, &c1)) { | |
898 | return NULL; | |
899 | } | |
900 | ||
901 | if (!expr_relop_from_token(ctx->lexer->token.type, NULL) | |
902 | && c1.n_values == 1 | |
903 | && c1.type == EXPR_C_INTEGER | |
904 | && c1.values[0].format == LEX_F_DECIMAL | |
905 | && !c1.values[0].masked | |
906 | && !c1.in_curlies) { | |
907 | uint64_t x = ntohll(c1.values[0].value.integer); | |
908 | if (x <= 1) { | |
909 | *atomic = true; | |
910 | expr_constant_set_destroy(&c1); | |
911 | return expr_create_boolean(x); | |
912 | } | |
913 | } | |
914 | ||
915 | enum expr_relop r1; | |
916 | struct expr_field f; | |
917 | if (!parse_relop(ctx, &r1) || !parse_field(ctx, &f)) { | |
918 | expr_constant_set_destroy(&c1); | |
919 | return NULL; | |
920 | } | |
921 | ||
922 | if (!expr_relop_from_token(ctx->lexer->token.type, NULL)) { | |
923 | return make_cmp(ctx, &f, expr_relop_turn(r1), &c1); | |
924 | } | |
925 | ||
926 | enum expr_relop r2; | |
927 | struct expr_constant_set c2; | |
928 | if (!parse_relop(ctx, &r2) || !parse_constant_set(ctx, &c2)) { | |
929 | expr_constant_set_destroy(&c1); | |
930 | return NULL; | |
931 | } else { | |
932 | /* Reject "1 == field == 2", "1 < field > 2", and so on. */ | |
933 | if (!(((r1 == EXPR_R_LT || r1 == EXPR_R_LE) && | |
934 | (r2 == EXPR_R_LT || r2 == EXPR_R_LE)) || | |
935 | ((r1 == EXPR_R_GT || r1 == EXPR_R_GE) && | |
936 | (r2 == EXPR_R_GT || r2 == EXPR_R_GE)))) { | |
937 | expr_error(ctx, "Range expressions must have the form " | |
938 | "`x < field < y' or `x > field > y', with each " | |
939 | "`<' optionally replaced by `<=' or `>' by `>=')."); | |
940 | expr_constant_set_destroy(&c1); | |
941 | expr_constant_set_destroy(&c2); | |
942 | return NULL; | |
943 | } | |
944 | ||
945 | struct expr *e1 = make_cmp(ctx, &f, expr_relop_turn(r1), &c1); | |
946 | struct expr *e2 = make_cmp(ctx, &f, r2, &c2); | |
947 | if (ctx->error) { | |
948 | expr_destroy(e1); | |
949 | expr_destroy(e2); | |
950 | return NULL; | |
951 | } | |
952 | return expr_combine(EXPR_T_AND, e1, e2); | |
953 | } | |
954 | } | |
955 | } | |
956 | ||
957 | static struct expr * | |
958 | expr_parse_not(struct expr_context *ctx) | |
959 | { | |
960 | bool atomic; | |
961 | ||
962 | if (lexer_match(ctx->lexer, LEX_T_LOG_NOT)) { | |
963 | ctx->not = !ctx->not; | |
964 | struct expr *expr = expr_parse_primary(ctx, &atomic); | |
965 | ctx->not = !ctx->not; | |
966 | ||
967 | if (expr) { | |
968 | if (!atomic) { | |
969 | expr_error(ctx, "Missing parentheses around operand of !."); | |
970 | expr_destroy(expr); | |
971 | return NULL; | |
972 | } | |
973 | expr_not(expr); | |
974 | } | |
975 | return expr; | |
976 | } else { | |
977 | return expr_parse_primary(ctx, &atomic); | |
978 | } | |
979 | } | |
980 | ||
981 | struct expr * | |
982 | expr_parse__(struct expr_context *ctx) | |
983 | { | |
984 | struct expr *e = expr_parse_not(ctx); | |
985 | if (!e) { | |
986 | return NULL; | |
987 | } | |
988 | ||
989 | enum lex_type lex_type = ctx->lexer->token.type; | |
990 | if (lex_type == LEX_T_LOG_AND || lex_type == LEX_T_LOG_OR) { | |
991 | enum expr_type expr_type | |
992 | = lex_type == LEX_T_LOG_AND ? EXPR_T_AND : EXPR_T_OR; | |
993 | ||
994 | lexer_get(ctx->lexer); | |
995 | do { | |
996 | struct expr *e2 = expr_parse_not(ctx); | |
997 | if (!e2) { | |
998 | expr_destroy(e); | |
999 | return NULL; | |
1000 | } | |
1001 | e = expr_combine(expr_type, e, e2); | |
1002 | } while (lexer_match(ctx->lexer, lex_type)); | |
1003 | if (ctx->lexer->token.type == LEX_T_LOG_AND | |
1004 | || ctx->lexer->token.type == LEX_T_LOG_OR) { | |
1005 | expr_destroy(e); | |
1006 | expr_error(ctx, | |
1007 | "&& and || must be parenthesized when used together."); | |
1008 | return NULL; | |
1009 | } | |
1010 | } | |
1011 | return e; | |
1012 | } | |
1013 | ||
1014 | /* Parses an expression using the symbols in 'symtab' from 'lexer'. If | |
1015 | * successful, returns the new expression and sets '*errorp' to NULL. On | |
1016 | * failure, returns NULL and sets '*errorp' to an explanatory error message. | |
1017 | * The caller must eventually free the returned expression (with | |
1018 | * expr_destroy()) or error (with free()). */ | |
1019 | struct expr * | |
1020 | expr_parse(struct lexer *lexer, const struct shash *symtab, char **errorp) | |
1021 | { | |
1022 | struct expr_context ctx; | |
1023 | ||
1024 | ctx.lexer = lexer; | |
1025 | ctx.symtab = symtab; | |
1026 | ctx.error = NULL; | |
1027 | ctx.not = false; | |
1028 | ||
1029 | struct expr *e = expr_parse__(&ctx); | |
1030 | *errorp = ctx.error; | |
1031 | ovs_assert((ctx.error != NULL) != (e != NULL)); | |
1032 | return e; | |
1033 | } | |
1034 | ||
1035 | /* Like expr_parse(), but the expression is taken from 's'. */ | |
1036 | struct expr * | |
1037 | expr_parse_string(const char *s, const struct shash *symtab, char **errorp) | |
1038 | { | |
1039 | struct lexer lexer; | |
1040 | struct expr *expr; | |
1041 | ||
1042 | lexer_init(&lexer, s); | |
1043 | lexer_get(&lexer); | |
1044 | expr = expr_parse(&lexer, symtab, errorp); | |
1045 | if (!errorp && lexer.token.type != LEX_T_END) { | |
1046 | *errorp = xstrdup("Extra tokens at end of input."); | |
1047 | expr_destroy(expr); | |
1048 | expr = NULL; | |
1049 | } | |
1050 | lexer_destroy(&lexer); | |
1051 | ||
1052 | return expr; | |
1053 | } | |
1054 | \f | |
1055 | static struct expr_symbol * | |
1056 | add_symbol(struct shash *symtab, const char *name, int width, | |
1057 | const char *prereqs, enum expr_level level, | |
1058 | bool must_crossproduct) | |
1059 | { | |
1060 | struct expr_symbol *symbol = xzalloc(sizeof *symbol); | |
1061 | symbol->name = xstrdup(name); | |
1062 | symbol->prereqs = prereqs && prereqs[0] ? xstrdup(prereqs) : NULL; | |
1063 | symbol->width = width; | |
1064 | symbol->level = level; | |
1065 | symbol->must_crossproduct = must_crossproduct; | |
1066 | shash_add_assert(symtab, symbol->name, symbol); | |
1067 | return symbol; | |
1068 | } | |
1069 | ||
1070 | /* Adds field 'id' to symbol table 'symtab' under the given 'name'. Whenever | |
1071 | * 'name' is referenced, expression annotation (see expr_annotate()) will | |
1072 | * ensure that 'prereqs' are also true. If 'must_crossproduct' is true, then | |
1073 | * conversion to flows will never attempt to use the field as a conjunctive | |
1074 | * match dimension (see "Crossproducting" in the large comment on struct | |
1075 | * expr_symbol in expr.h for an example). | |
1076 | * | |
1077 | * A given field 'id' must only be used for a single symbol in a symbol table. | |
1078 | * Use subfields to duplicate or subset a field (you can even make a subfield | |
1079 | * include all the bits of the "parent" field if you like). */ | |
1080 | struct expr_symbol * | |
1081 | expr_symtab_add_field(struct shash *symtab, const char *name, | |
1082 | enum mf_field_id id, const char *prereqs, | |
1083 | bool must_crossproduct) | |
1084 | { | |
1085 | const struct mf_field *field = mf_from_id(id); | |
1086 | struct expr_symbol *symbol; | |
1087 | ||
1088 | symbol = add_symbol(symtab, name, field->n_bits, prereqs, | |
1089 | (field->maskable == MFM_FULLY | |
1090 | ? EXPR_L_ORDINAL | |
1091 | : EXPR_L_NOMINAL), | |
1092 | must_crossproduct); | |
1093 | symbol->field = field; | |
1094 | return symbol; | |
1095 | } | |
1096 | ||
1097 | static bool | |
1098 | parse_field_from_string(const char *s, const struct shash *symtab, | |
1099 | struct expr_field *field, char **errorp) | |
1100 | { | |
1101 | struct lexer lexer; | |
1102 | lexer_init(&lexer, s); | |
1103 | lexer_get(&lexer); | |
1104 | ||
1105 | struct expr_context ctx; | |
1106 | ctx.lexer = &lexer; | |
1107 | ctx.symtab = symtab; | |
1108 | ctx.error = NULL; | |
1109 | ctx.not = false; | |
1110 | ||
1111 | bool ok = parse_field(&ctx, field); | |
1112 | if (!ok) { | |
1113 | *errorp = ctx.error; | |
1114 | } else if (lexer.token.type != LEX_T_END) { | |
1115 | *errorp = xstrdup("Extra tokens at end of input."); | |
1116 | ok = false; | |
1117 | } | |
1118 | ||
1119 | lexer_destroy(&lexer); | |
1120 | ||
1121 | return ok; | |
1122 | } | |
1123 | ||
1124 | /* Adds 'name' as a subfield of a larger field in 'symtab'. Whenever | |
1125 | * 'name' is referenced, expression annotation (see expr_annotate()) will | |
1126 | * ensure that 'prereqs' are also true. | |
1127 | * | |
1128 | * 'subfield' must describe the subfield as a string, e.g. "vlan.tci[0..11]" | |
1129 | * for the low 12 bits of a larger field named "vlan.tci". */ | |
1130 | struct expr_symbol * | |
1131 | expr_symtab_add_subfield(struct shash *symtab, const char *name, | |
1132 | const char *prereqs, const char *subfield) | |
1133 | { | |
1134 | struct expr_symbol *symbol; | |
1135 | struct expr_field f; | |
1136 | char *error; | |
1137 | ||
1138 | if (!parse_field_from_string(subfield, symtab, &f, &error)) { | |
1139 | VLOG_WARN("%s: error parsing %s subfield (%s)", subfield, name, error); | |
1140 | free(error); | |
1141 | return NULL; | |
1142 | } | |
1143 | ||
1144 | enum expr_level level = f.symbol->level; | |
1145 | if (level != EXPR_L_ORDINAL) { | |
1146 | VLOG_WARN("can't define %s as subfield of %s field %s", | |
1147 | name, expr_level_to_string(level), f.symbol->name); | |
1148 | } | |
1149 | ||
1150 | symbol = add_symbol(symtab, name, f.n_bits, prereqs, level, false); | |
1151 | symbol->expansion = xstrdup(subfield); | |
1152 | return symbol; | |
1153 | } | |
1154 | ||
1155 | /* Adds a string-valued symbol named 'name' to 'symtab' with the specified | |
1156 | * 'prereqs'. */ | |
1157 | struct expr_symbol * | |
1158 | expr_symtab_add_string(struct shash *symtab, const char *name, | |
f386a8a7 | 1159 | enum mf_field_id id, const char *prereqs) |
e0840f11 | 1160 | { |
f386a8a7 BP |
1161 | const struct mf_field *field = mf_from_id(id); |
1162 | struct expr_symbol *symbol; | |
1163 | ||
1164 | symbol = add_symbol(symtab, name, 0, prereqs, EXPR_L_NOMINAL, false); | |
1165 | symbol->field = field; | |
1166 | return symbol; | |
e0840f11 BP |
1167 | } |
1168 | ||
1169 | static enum expr_level | |
1170 | expr_get_level(const struct expr *expr) | |
1171 | { | |
1172 | const struct expr *sub; | |
1173 | enum expr_level level = EXPR_L_ORDINAL; | |
1174 | ||
1175 | switch (expr->type) { | |
1176 | case EXPR_T_CMP: | |
1177 | return (expr->cmp.symbol->level == EXPR_L_NOMINAL | |
1178 | ? EXPR_L_NOMINAL | |
1179 | : EXPR_L_BOOLEAN); | |
1180 | ||
1181 | case EXPR_T_AND: | |
1182 | case EXPR_T_OR: | |
1183 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1184 | enum expr_level sub_level = expr_get_level(sub); | |
1185 | level = MIN(level, sub_level); | |
1186 | } | |
1187 | return level; | |
1188 | ||
1189 | case EXPR_T_BOOLEAN: | |
1190 | return EXPR_L_BOOLEAN; | |
1191 | ||
1192 | default: | |
1193 | OVS_NOT_REACHED(); | |
1194 | } | |
1195 | } | |
1196 | ||
1197 | static enum expr_level | |
1198 | expr_parse_level(const char *s, const struct shash *symtab, char **errorp) | |
1199 | { | |
1200 | struct expr *expr = expr_parse_string(s, symtab, errorp); | |
1201 | enum expr_level level = expr ? expr_get_level(expr) : EXPR_L_NOMINAL; | |
1202 | expr_destroy(expr); | |
1203 | return level; | |
1204 | } | |
1205 | ||
1206 | /* Adds a predicate symbol, whose value is the given Boolean 'expression', | |
1207 | * named 'name' to 'symtab'. For example, "ip4 && ip4.proto == 1" might be an | |
1208 | * appropriate predicate named "tcp4". */ | |
1209 | struct expr_symbol * | |
1210 | expr_symtab_add_predicate(struct shash *symtab, const char *name, | |
1211 | const char *expansion) | |
1212 | { | |
1213 | struct expr_symbol *symbol; | |
1214 | enum expr_level level; | |
1215 | char *error; | |
1216 | ||
1217 | level = expr_parse_level(expansion, symtab, &error); | |
1218 | if (error) { | |
1219 | VLOG_WARN("%s: error parsing %s expansion (%s)", | |
1220 | expansion, name, error); | |
1221 | free(error); | |
1222 | return NULL; | |
1223 | } | |
1224 | ||
1225 | symbol = add_symbol(symtab, name, 1, NULL, level, false); | |
1226 | symbol->expansion = xstrdup(expansion); | |
1227 | return symbol; | |
1228 | } | |
1229 | ||
1230 | /* Destroys 'symtab' and all of its symbols. */ | |
1231 | void | |
1232 | expr_symtab_destroy(struct shash *symtab) | |
1233 | { | |
1234 | struct shash_node *node, *next; | |
1235 | ||
1236 | SHASH_FOR_EACH_SAFE (node, next, symtab) { | |
1237 | struct expr_symbol *symbol = node->data; | |
1238 | ||
1239 | shash_delete(symtab, node); | |
1240 | free(symbol->name); | |
1241 | free(symbol->prereqs); | |
1242 | free(symbol->expansion); | |
1243 | free(symbol); | |
1244 | } | |
1245 | } | |
1246 | \f | |
1247 | /* Cloning. */ | |
1248 | ||
1249 | static struct expr * | |
1250 | expr_clone_cmp(struct expr *expr) | |
1251 | { | |
1252 | struct expr *new = xmemdup(expr, sizeof *expr); | |
1253 | if (!new->cmp.symbol->width) { | |
1254 | new->cmp.string = xstrdup(new->cmp.string); | |
1255 | } | |
1256 | return new; | |
1257 | } | |
1258 | ||
1259 | static struct expr * | |
1260 | expr_clone_andor(struct expr *expr) | |
1261 | { | |
1262 | struct expr *new = expr_create_andor(expr->type); | |
1263 | struct expr *sub; | |
1264 | ||
1265 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1266 | struct expr *new_sub = expr_clone(sub); | |
1267 | list_push_back(&new->andor, &new_sub->node); | |
1268 | } | |
1269 | return new; | |
1270 | } | |
1271 | ||
1272 | /* Returns a clone of 'expr'. This is a "deep copy": neither the returned | |
1273 | * expression nor any of its substructure will be shared with 'expr'. */ | |
1274 | struct expr * | |
1275 | expr_clone(struct expr *expr) | |
1276 | { | |
1277 | switch (expr->type) { | |
1278 | case EXPR_T_CMP: | |
1279 | return expr_clone_cmp(expr); | |
1280 | ||
1281 | case EXPR_T_AND: | |
1282 | case EXPR_T_OR: | |
1283 | return expr_clone_andor(expr); | |
1284 | ||
1285 | case EXPR_T_BOOLEAN: | |
1286 | return expr_create_boolean(expr->boolean); | |
1287 | } | |
1288 | OVS_NOT_REACHED(); | |
1289 | } | |
1290 | \f | |
1291 | /* Destroys 'expr' and all of the sub-expressions it references. */ | |
1292 | void | |
1293 | expr_destroy(struct expr *expr) | |
1294 | { | |
1295 | if (!expr) { | |
1296 | return; | |
1297 | } | |
1298 | ||
1299 | struct expr *sub, *next; | |
1300 | ||
1301 | switch (expr->type) { | |
1302 | case EXPR_T_CMP: | |
1303 | if (!expr->cmp.symbol->width) { | |
1304 | free(expr->cmp.string); | |
1305 | } | |
1306 | break; | |
1307 | ||
1308 | case EXPR_T_AND: | |
1309 | case EXPR_T_OR: | |
1310 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
1311 | list_remove(&sub->node); | |
1312 | expr_destroy(sub); | |
1313 | } | |
1314 | break; | |
1315 | ||
1316 | case EXPR_T_BOOLEAN: | |
1317 | break; | |
1318 | } | |
1319 | free(expr); | |
1320 | } | |
1321 | \f | |
1322 | /* Annotation. */ | |
1323 | ||
1324 | /* An element in a linked list of symbols. | |
1325 | * | |
1326 | * Used to detect when a symbol is being expanded recursively, to allow | |
1327 | * flagging an error. */ | |
1328 | struct annotation_nesting { | |
1329 | struct ovs_list node; | |
1330 | const struct expr_symbol *symbol; | |
1331 | }; | |
1332 | ||
1333 | struct expr *expr_annotate__(struct expr *, const struct shash *symtab, | |
1334 | struct ovs_list *nesting, char **errorp); | |
1335 | ||
1336 | static struct expr * | |
1337 | parse_and_annotate(const char *s, const struct shash *symtab, | |
1338 | struct ovs_list *nesting, char **errorp) | |
1339 | { | |
1340 | char *error; | |
1341 | struct expr *expr; | |
1342 | ||
1343 | expr = expr_parse_string(s, symtab, &error); | |
1344 | if (expr) { | |
1345 | expr = expr_annotate__(expr, symtab, nesting, &error); | |
1346 | } | |
1347 | if (!expr) { | |
1348 | *errorp = xasprintf("Error parsing expression `%s' encountered as " | |
1349 | "prerequisite or predicate of initial expression: " | |
1350 | "%s", s, error); | |
1351 | free(error); | |
1352 | } | |
1353 | return expr; | |
1354 | } | |
1355 | ||
1356 | static struct expr * | |
1357 | expr_annotate_cmp(struct expr *expr, const struct shash *symtab, | |
1358 | struct ovs_list *nesting, char **errorp) | |
1359 | { | |
1360 | const struct expr_symbol *symbol = expr->cmp.symbol; | |
1361 | const struct annotation_nesting *iter; | |
1362 | LIST_FOR_EACH (iter, node, nesting) { | |
1363 | if (iter->symbol == symbol) { | |
1364 | *errorp = xasprintf("Recursive expansion of symbol `%s'.", | |
1365 | symbol->name); | |
1366 | expr_destroy(expr); | |
1367 | return NULL; | |
1368 | } | |
1369 | } | |
1370 | ||
1371 | struct annotation_nesting an; | |
1372 | an.symbol = symbol; | |
1373 | list_push_back(nesting, &an.node); | |
1374 | ||
1375 | struct expr *prereqs = NULL; | |
1376 | if (symbol->prereqs) { | |
1377 | prereqs = parse_and_annotate(symbol->prereqs, symtab, nesting, errorp); | |
1378 | if (!prereqs) { | |
1379 | goto error; | |
1380 | } | |
1381 | } | |
1382 | ||
1383 | if (symbol->expansion) { | |
1384 | if (symbol->level == EXPR_L_ORDINAL) { | |
1385 | struct expr_field field; | |
1386 | ||
1387 | if (!parse_field_from_string(symbol->expansion, symtab, | |
1388 | &field, errorp)) { | |
1389 | goto error; | |
1390 | } | |
1391 | ||
1392 | expr->cmp.symbol = field.symbol; | |
1393 | mf_subvalue_shift(&expr->cmp.value, field.ofs); | |
1394 | mf_subvalue_shift(&expr->cmp.mask, field.ofs); | |
1395 | } else { | |
1396 | struct expr *expansion; | |
1397 | ||
1398 | expansion = parse_and_annotate(symbol->expansion, symtab, | |
1399 | nesting, errorp); | |
1400 | if (!expansion) { | |
1401 | goto error; | |
1402 | } | |
1403 | ||
1404 | bool positive = (expr->cmp.value.integer & htonll(1)) != 0; | |
1405 | positive ^= expr->cmp.relop == EXPR_R_NE; | |
1406 | if (!positive) { | |
1407 | expr_not(expansion); | |
1408 | } | |
1409 | ||
1410 | expr_destroy(expr); | |
1411 | expr = expansion; | |
1412 | } | |
1413 | } | |
1414 | ||
1415 | list_remove(&an.node); | |
1416 | return prereqs ? expr_combine(EXPR_T_AND, expr, prereqs) : expr; | |
1417 | ||
1418 | error: | |
1419 | expr_destroy(expr); | |
1420 | expr_destroy(prereqs); | |
1421 | list_remove(&an.node); | |
1422 | return NULL; | |
1423 | } | |
1424 | ||
1425 | struct expr * | |
1426 | expr_annotate__(struct expr *expr, const struct shash *symtab, | |
1427 | struct ovs_list *nesting, char **errorp) | |
1428 | { | |
1429 | switch (expr->type) { | |
1430 | case EXPR_T_CMP: | |
1431 | return expr_annotate_cmp(expr, symtab, nesting, errorp); | |
1432 | ||
1433 | case EXPR_T_AND: | |
1434 | case EXPR_T_OR: { | |
1435 | struct expr *sub, *next; | |
1436 | ||
1437 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
1438 | list_remove(&sub->node); | |
1439 | struct expr *new_sub = expr_annotate__(sub, symtab, | |
1440 | nesting, errorp); | |
1441 | if (!new_sub) { | |
1442 | expr_destroy(expr); | |
1443 | return NULL; | |
1444 | } | |
1445 | expr_insert_andor(expr, next, new_sub); | |
1446 | } | |
1447 | *errorp = NULL; | |
1448 | return expr; | |
1449 | } | |
1450 | ||
1451 | case EXPR_T_BOOLEAN: | |
1452 | *errorp = NULL; | |
1453 | return expr; | |
1454 | ||
1455 | default: | |
1456 | OVS_NOT_REACHED(); | |
1457 | } | |
1458 | } | |
1459 | ||
1460 | /* "Annotates" 'expr', which does the following: | |
1461 | * | |
1462 | * - Applies prerequisites, by locating each comparison operator whose | |
1463 | * field has a prerequisite and adding a logical AND against those | |
1464 | * prerequisites. | |
1465 | * | |
1466 | * - Expands references to subfield symbols, by replacing them by | |
1467 | * references to their underlying field symbols (suitably shifted). | |
1468 | * | |
1469 | * - Expands references to predicate symbols, by replacing them by the | |
1470 | * expressions that they expand to. | |
1471 | * | |
1472 | * In each case, annotation occurs recursively as necessary. */ | |
1473 | struct expr * | |
1474 | expr_annotate(struct expr *expr, const struct shash *symtab, char **errorp) | |
1475 | { | |
1476 | struct ovs_list nesting = OVS_LIST_INITIALIZER(&nesting); | |
1477 | return expr_annotate__(expr, symtab, &nesting, errorp); | |
1478 | } | |
1479 | \f | |
1480 | static struct expr * | |
1481 | expr_simplify_ne(struct expr *expr) | |
1482 | { | |
1483 | struct expr *new = NULL; | |
1484 | const union mf_subvalue *value = &expr->cmp.value; | |
1485 | const union mf_subvalue *mask = &expr->cmp.mask; | |
1486 | int w = expr->cmp.symbol->width; | |
1487 | int i; | |
1488 | ||
1489 | for (i = 0; (i = bitwise_scan(mask, sizeof *mask, true, i, w)) < w; i++) { | |
1490 | struct expr *e; | |
1491 | ||
1492 | e = xzalloc(sizeof *e); | |
1493 | e->type = EXPR_T_CMP; | |
1494 | e->cmp.symbol = expr->cmp.symbol; | |
1495 | e->cmp.relop = EXPR_R_EQ; | |
1496 | bitwise_put_bit(&e->cmp.value, sizeof e->cmp.value, i, | |
1497 | !bitwise_get_bit(value, sizeof *value, i)); | |
1498 | bitwise_put1(&e->cmp.mask, sizeof e->cmp.mask, i); | |
1499 | ||
1500 | new = expr_combine(EXPR_T_OR, new, e); | |
1501 | } | |
1502 | ovs_assert(new); | |
1503 | ||
1504 | expr_destroy(expr); | |
1505 | ||
1506 | return new; | |
1507 | } | |
1508 | ||
1509 | static struct expr * | |
1510 | expr_simplify_relational(struct expr *expr) | |
1511 | { | |
1512 | const union mf_subvalue *value = &expr->cmp.value; | |
1513 | int start, n_bits, end; | |
1514 | ||
1515 | find_bitwise_range(&expr->cmp.mask, expr->cmp.symbol->width, | |
1516 | &start, &n_bits); | |
1517 | ovs_assert(n_bits > 0); | |
1518 | end = start + n_bits; | |
1519 | ||
1520 | struct expr *new; | |
1521 | if (expr->cmp.relop == EXPR_R_LE || expr->cmp.relop == EXPR_R_GE) { | |
1522 | new = xmemdup(expr, sizeof *expr); | |
1523 | new->cmp.relop = EXPR_R_EQ; | |
1524 | } else { | |
1525 | new = NULL; | |
1526 | } | |
1527 | ||
1528 | bool b = expr->cmp.relop == EXPR_R_LT || expr->cmp.relop == EXPR_R_LE; | |
1529 | for (int z = bitwise_scan(value, sizeof *value, b, start, end); | |
1530 | z < end; | |
1531 | z = bitwise_scan(value, sizeof *value, b, z + 1, end)) { | |
1532 | struct expr *e; | |
1533 | ||
1534 | e = xmemdup(expr, sizeof *expr); | |
1535 | e->cmp.relop = EXPR_R_EQ; | |
1536 | bitwise_toggle_bit(&e->cmp.value, sizeof e->cmp.value, z); | |
1537 | bitwise_zero(&e->cmp.value, sizeof e->cmp.value, start, z - start); | |
1538 | bitwise_zero(&e->cmp.mask, sizeof e->cmp.mask, start, z - start); | |
1539 | new = expr_combine(EXPR_T_OR, new, e); | |
1540 | } | |
1541 | expr_destroy(expr); | |
1542 | return new ? new : expr_create_boolean(false); | |
1543 | } | |
1544 | ||
1545 | /* Takes ownership of 'expr' and returns an equivalent expression whose | |
1546 | * EXPR_T_CMP nodes use only tests for equality (EXPR_R_EQ). */ | |
1547 | struct expr * | |
1548 | expr_simplify(struct expr *expr) | |
1549 | { | |
1550 | struct expr *sub, *next; | |
1551 | ||
1552 | switch (expr->type) { | |
1553 | case EXPR_T_CMP: | |
1554 | return (expr->cmp.relop == EXPR_R_EQ || !expr->cmp.symbol->width ? expr | |
1555 | : expr->cmp.relop == EXPR_R_NE ? expr_simplify_ne(expr) | |
1556 | : expr_simplify_relational(expr)); | |
1557 | ||
1558 | case EXPR_T_AND: | |
1559 | case EXPR_T_OR: | |
1560 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
1561 | list_remove(&sub->node); | |
1562 | expr_insert_andor(expr, next, expr_simplify(sub)); | |
1563 | } | |
1564 | return expr_fix(expr); | |
1565 | ||
1566 | case EXPR_T_BOOLEAN: | |
1567 | return expr; | |
1568 | } | |
1569 | OVS_NOT_REACHED(); | |
1570 | } | |
1571 | \f | |
1572 | static const struct expr_symbol * | |
1573 | expr_is_cmp(const struct expr *expr) | |
1574 | { | |
1575 | switch (expr->type) { | |
1576 | case EXPR_T_CMP: | |
1577 | return expr->cmp.symbol; | |
1578 | ||
1579 | case EXPR_T_AND: | |
1580 | case EXPR_T_OR: { | |
1581 | const struct expr_symbol *prev = NULL; | |
1582 | struct expr *sub; | |
1583 | ||
1584 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1585 | const struct expr_symbol *symbol = expr_is_cmp(sub); | |
1586 | if (!symbol || (prev && symbol != prev)) { | |
1587 | return NULL; | |
1588 | } | |
1589 | prev = symbol; | |
1590 | } | |
1591 | return prev; | |
1592 | } | |
1593 | ||
1594 | case EXPR_T_BOOLEAN: | |
1595 | return NULL; | |
1596 | ||
1597 | default: | |
1598 | OVS_NOT_REACHED(); | |
1599 | } | |
1600 | } | |
1601 | ||
1602 | struct expr_sort { | |
1603 | struct expr *expr; | |
1604 | const struct expr_symbol *relop; | |
1605 | enum expr_type type; | |
1606 | }; | |
1607 | ||
1608 | static int | |
1609 | compare_expr_sort(const void *a_, const void *b_) | |
1610 | { | |
1611 | const struct expr_sort *a = a_; | |
1612 | const struct expr_sort *b = b_; | |
1613 | ||
1614 | if (a->type != b->type) { | |
1615 | return a->type < b->type ? -1 : 1; | |
1616 | } else if (a->relop) { | |
1617 | int cmp = strcmp(a->relop->name, b->relop->name); | |
1618 | if (cmp) { | |
1619 | return cmp; | |
1620 | } | |
1621 | ||
1622 | enum expr_type a_type = a->expr->type; | |
1623 | enum expr_type b_type = a->expr->type; | |
1624 | return a_type < b_type ? -1 : a_type > b_type; | |
1625 | } else if (a->type == EXPR_T_AND || a->type == EXPR_T_OR) { | |
1626 | size_t a_len = list_size(&a->expr->andor); | |
1627 | size_t b_len = list_size(&b->expr->andor); | |
1628 | return a_len < b_len ? -1 : a_len > b_len; | |
1629 | } else { | |
1630 | return 0; | |
1631 | } | |
1632 | } | |
1633 | ||
1634 | static struct expr *crush_cmps(struct expr *, const struct expr_symbol *); | |
1635 | ||
1636 | static struct expr * | |
1637 | crush_and(struct expr *expr, const struct expr_symbol *symbol) | |
1638 | { | |
1639 | ovs_assert(!list_is_short(&expr->andor)); | |
1640 | ||
1641 | union mf_subvalue value, mask; | |
1642 | memset(&value, 0, sizeof value); | |
1643 | memset(&mask, 0, sizeof mask); | |
1644 | ||
1645 | struct expr *sub, *next = NULL; | |
1646 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
1647 | list_remove(&sub->node); | |
1648 | struct expr *new = crush_cmps(sub, symbol); | |
1649 | switch (new->type) { | |
1650 | case EXPR_T_CMP: | |
1651 | if (!mf_subvalue_intersect(&value, &mask, | |
1652 | &new->cmp.value, &new->cmp.mask, | |
1653 | &value, &mask)) { | |
1654 | expr_destroy(new); | |
1655 | expr_destroy(expr); | |
1656 | return expr_create_boolean(false); | |
1657 | } | |
1658 | expr_destroy(new); | |
1659 | break; | |
1660 | case EXPR_T_AND: | |
1661 | OVS_NOT_REACHED(); | |
1662 | case EXPR_T_OR: | |
1663 | list_insert(&next->node, &new->node); | |
1664 | break; | |
1665 | case EXPR_T_BOOLEAN: | |
1666 | if (!new->boolean) { | |
1667 | expr_destroy(expr); | |
1668 | return new; | |
1669 | } | |
1670 | free(new); | |
1671 | break; | |
1672 | } | |
1673 | } | |
1674 | if (list_is_empty(&expr->andor)) { | |
1675 | if (is_all_zeros(&mask, sizeof mask)) { | |
1676 | expr_destroy(expr); | |
1677 | return expr_create_boolean(true); | |
1678 | } else { | |
1679 | struct expr *cmp; | |
1680 | cmp = xmalloc(sizeof *cmp); | |
1681 | cmp->type = EXPR_T_CMP; | |
1682 | cmp->cmp.symbol = symbol; | |
1683 | cmp->cmp.relop = EXPR_R_EQ; | |
1684 | cmp->cmp.value = value; | |
1685 | cmp->cmp.mask = mask; | |
1686 | expr_destroy(expr); | |
1687 | return cmp; | |
1688 | } | |
1689 | } else if (list_is_short(&expr->andor)) { | |
1690 | /* Transform "a && (b || c || d)" into "ab || ac || ad" where "ab" is | |
1691 | * computed as "a && b", etc. */ | |
1692 | struct expr *disjuncts = expr_from_node(list_pop_front(&expr->andor)); | |
1693 | struct expr *or; | |
1694 | ||
1695 | or = xmalloc(sizeof *or); | |
1696 | or->type = EXPR_T_OR; | |
1697 | list_init(&or->andor); | |
1698 | ||
1699 | ovs_assert(disjuncts->type == EXPR_T_OR); | |
1700 | LIST_FOR_EACH_SAFE (sub, next, node, &disjuncts->andor) { | |
1701 | ovs_assert(sub->type == EXPR_T_CMP); | |
1702 | list_remove(&sub->node); | |
1703 | if (mf_subvalue_intersect(&value, &mask, | |
1704 | &sub->cmp.value, &sub->cmp.mask, | |
1705 | &sub->cmp.value, &sub->cmp.mask)) { | |
1706 | list_push_back(&or->andor, &sub->node); | |
1707 | } else { | |
1708 | free(sub); | |
1709 | } | |
1710 | } | |
1711 | free(disjuncts); | |
1712 | free(expr); | |
1713 | if (list_is_empty(&or->andor)) { | |
1714 | free(or); | |
1715 | return expr_create_boolean(false); | |
1716 | } else if (list_is_short(&or->andor)) { | |
1717 | struct expr *cmp = expr_from_node(list_pop_front(&or->andor)); | |
1718 | free(or); | |
1719 | return cmp; | |
1720 | } else { | |
1721 | return or; | |
1722 | } | |
1723 | } else { | |
1724 | /* Transform "x && (a0 || a1) && (b0 || b1) && ..." into | |
1725 | * "(xa0b0 || xa0b1 || xa1b0 || xa1b1) && ...". */ | |
1726 | struct expr *as = expr_from_node(list_pop_front(&expr->andor)); | |
1727 | struct expr *bs = expr_from_node(list_pop_front(&expr->andor)); | |
1728 | struct expr *new = NULL; | |
1729 | struct expr *or; | |
1730 | ||
1731 | or = xmalloc(sizeof *or); | |
1732 | or->type = EXPR_T_OR; | |
1733 | list_init(&or->andor); | |
1734 | ||
1735 | struct expr *a; | |
1736 | LIST_FOR_EACH (a, node, &as->andor) { | |
1737 | union mf_subvalue a_value, a_mask; | |
1738 | ||
1739 | ovs_assert(a->type == EXPR_T_CMP); | |
1740 | if (!mf_subvalue_intersect(&value, &mask, | |
1741 | &a->cmp.value, &a->cmp.mask, | |
1742 | &a_value, &a_mask)) { | |
1743 | continue; | |
1744 | } | |
1745 | ||
1746 | struct expr *b; | |
1747 | LIST_FOR_EACH (b, node, &bs->andor) { | |
1748 | ovs_assert(b->type == EXPR_T_CMP); | |
1749 | if (!new) { | |
1750 | new = xmalloc(sizeof *new); | |
1751 | new->type = EXPR_T_CMP; | |
1752 | new->cmp.symbol = symbol; | |
1753 | new->cmp.relop = EXPR_R_EQ; | |
1754 | } | |
1755 | if (mf_subvalue_intersect(&a_value, &a_mask, | |
1756 | &b->cmp.value, &b->cmp.mask, | |
1757 | &new->cmp.value, &new->cmp.mask)) { | |
1758 | list_push_back(&or->andor, &new->node); | |
1759 | new = NULL; | |
1760 | } | |
1761 | } | |
1762 | } | |
1763 | expr_destroy(as); | |
1764 | expr_destroy(bs); | |
1765 | free(new); | |
1766 | ||
1767 | if (list_is_empty(&or->andor)) { | |
1768 | expr_destroy(expr); | |
1769 | free(or); | |
1770 | return expr_create_boolean(false); | |
1771 | } else if (list_is_short(&or->andor)) { | |
1772 | struct expr *cmp = expr_from_node(list_pop_front(&or->andor)); | |
1773 | free(or); | |
1774 | if (list_is_empty(&expr->andor)) { | |
1775 | expr_destroy(expr); | |
1776 | return crush_cmps(cmp, symbol); | |
1777 | } else { | |
1778 | return crush_cmps(expr_combine(EXPR_T_AND, cmp, expr), symbol); | |
1779 | } | |
1780 | } else if (!list_is_empty(&expr->andor)) { | |
1781 | struct expr *e = expr_combine(EXPR_T_AND, or, expr); | |
1782 | ovs_assert(!list_is_short(&e->andor)); | |
1783 | return crush_cmps(e, symbol); | |
1784 | } else { | |
1785 | expr_destroy(expr); | |
1786 | return crush_cmps(or, symbol); | |
1787 | } | |
1788 | } | |
1789 | } | |
1790 | ||
1791 | static int | |
1792 | compare_expr(const void *a_, const void *b_) | |
1793 | { | |
1794 | const struct expr *const *ap = a_; | |
1795 | const struct expr *const *bp = b_; | |
1796 | const struct expr *a = *ap; | |
1797 | const struct expr *b = *bp; | |
1798 | int d = memcmp(&a->cmp.value, &b->cmp.value, sizeof a->cmp.value); | |
1799 | if (!d) { | |
1800 | d = memcmp(&a->cmp.mask, &b->cmp.mask, sizeof a->cmp.mask); | |
1801 | } | |
1802 | return d; | |
1803 | } | |
1804 | ||
1805 | static struct expr * | |
1806 | crush_or(struct expr *expr, const struct expr_symbol *symbol) | |
1807 | { | |
1808 | struct expr *sub, *next = NULL; | |
1809 | ||
1810 | /* First, crush all the subexpressions. That might eliminate the | |
1811 | * OR-expression entirely; if so, return the result. */ | |
1812 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
1813 | list_remove(&sub->node); | |
1814 | expr_insert_andor(expr, next, crush_cmps(sub, symbol)); | |
1815 | } | |
1816 | expr = expr_fix(expr); | |
1817 | if (expr->type != EXPR_T_OR) { | |
1818 | return expr; | |
1819 | } | |
1820 | ||
1821 | /* Eliminate duplicates by sorting the subexpressions. */ | |
1822 | size_t n = list_size(&expr->andor); | |
1823 | struct expr **subs = xmalloc(n * sizeof *subs); | |
1824 | ||
1825 | size_t i = 0; | |
1826 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1827 | subs[i++] = sub; | |
1828 | } | |
1829 | ovs_assert(i == n); | |
1830 | ||
1831 | qsort(subs, n, sizeof *subs, compare_expr); | |
1832 | ||
1833 | list_init(&expr->andor); | |
1834 | list_push_back(&expr->andor, &subs[0]->node); | |
1835 | for (i = 1; i < n; i++) { | |
1836 | struct expr *a = expr_from_node(list_back(&expr->andor)); | |
1837 | struct expr *b = subs[i]; | |
1838 | if (memcmp(&a->cmp.value, &b->cmp.value, sizeof a->cmp.value) | |
1839 | || memcmp(&a->cmp.mask, &b->cmp.mask, sizeof a->cmp.mask)) { | |
1840 | list_push_back(&expr->andor, &b->node); | |
1841 | } else { | |
1842 | free(b); | |
1843 | } | |
1844 | } | |
1845 | free(subs); | |
1846 | return expr_fix(expr); | |
1847 | } | |
1848 | ||
1849 | /* Converts 'expr', which must be a cmp in the sense determined by | |
1850 | * expr_is_cmp(). Returns a cmp, a disjunction of cmps, or a boolean. */ | |
1851 | static struct expr * | |
1852 | crush_cmps(struct expr *expr, const struct expr_symbol *symbol) | |
1853 | { | |
1854 | switch (expr->type) { | |
1855 | case EXPR_T_OR: | |
1856 | return crush_or(expr, symbol); | |
1857 | ||
1858 | case EXPR_T_AND: | |
1859 | return crush_and(expr, symbol); | |
1860 | ||
1861 | case EXPR_T_CMP: | |
1862 | return expr; | |
1863 | ||
1864 | case EXPR_T_BOOLEAN: | |
1865 | return expr; | |
1866 | ||
1867 | default: | |
1868 | OVS_NOT_REACHED(); | |
1869 | } | |
1870 | } | |
1871 | ||
1872 | static struct expr * | |
1873 | expr_sort(struct expr *expr) | |
1874 | { | |
1875 | size_t n = list_size(&expr->andor); | |
1876 | struct expr_sort *subs = xmalloc(n * sizeof *subs); | |
1877 | struct expr *sub; | |
1878 | size_t i; | |
1879 | ||
1880 | i = 0; | |
1881 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1882 | subs[i].expr = sub; | |
1883 | subs[i].relop = expr_is_cmp(sub); | |
1884 | subs[i].type = subs[i].relop ? EXPR_T_CMP : sub->type; | |
1885 | i++; | |
1886 | } | |
1887 | ovs_assert(i == n); | |
1888 | ||
1889 | qsort(subs, n, sizeof *subs, compare_expr_sort); | |
1890 | ||
1891 | list_init(&expr->andor); | |
1892 | for (int i = 0; i < n; ) { | |
1893 | if (subs[i].relop) { | |
1894 | int j; | |
1895 | for (j = i + 1; j < n; j++) { | |
1896 | if (subs[i].relop != subs[j].relop) { | |
1897 | break; | |
1898 | } | |
1899 | } | |
1900 | ||
1901 | struct expr *crushed; | |
1902 | if (j == i + 1) { | |
1903 | crushed = crush_cmps(subs[i].expr, subs[i].relop); | |
1904 | } else { | |
1905 | struct expr *combined = subs[i].expr; | |
1906 | for (int k = i + 1; k < j; k++) { | |
1907 | combined = expr_combine(EXPR_T_AND, combined, | |
1908 | subs[k].expr); | |
1909 | } | |
1910 | ovs_assert(!list_is_short(&combined->andor)); | |
1911 | crushed = crush_cmps(combined, subs[i].relop); | |
1912 | } | |
1913 | if (crushed->type == EXPR_T_BOOLEAN) { | |
1914 | if (!crushed->boolean) { | |
1915 | for (int k = j; k < n; k++) { | |
1916 | expr_destroy(subs[k].expr); | |
1917 | } | |
1918 | expr_destroy(expr); | |
1919 | expr = crushed; | |
1920 | break; | |
1921 | } else { | |
1922 | free(crushed); | |
1923 | } | |
1924 | } else { | |
1925 | expr = expr_combine(EXPR_T_AND, expr, crushed); | |
1926 | } | |
1927 | i = j; | |
1928 | } else { | |
1929 | expr = expr_combine(EXPR_T_AND, expr, subs[i++].expr); | |
1930 | } | |
1931 | } | |
1932 | free(subs); | |
1933 | ||
1934 | return expr; | |
1935 | } | |
1936 | ||
1937 | static struct expr *expr_normalize_or(struct expr *expr); | |
1938 | ||
1939 | /* Returns 'expr', which is an AND, reduced to OR(AND(clause)) where | |
1940 | * a clause is a cmp or a disjunction of cmps on a single field. */ | |
1941 | static struct expr * | |
1942 | expr_normalize_and(struct expr *expr) | |
1943 | { | |
1944 | ovs_assert(expr->type == EXPR_T_AND); | |
1945 | ||
1946 | expr = expr_sort(expr); | |
1947 | if (expr->type != EXPR_T_AND) { | |
1948 | ovs_assert(expr->type == EXPR_T_BOOLEAN); | |
1949 | return expr; | |
1950 | } | |
1951 | ||
1952 | struct expr *a, *b; | |
1953 | LIST_FOR_EACH_SAFE (a, b, node, &expr->andor) { | |
1954 | if (&b->node == &expr->andor | |
1955 | || a->type != EXPR_T_CMP || b->type != EXPR_T_CMP) { | |
1956 | } else if (a->cmp.symbol != b->cmp.symbol) { | |
1957 | continue; | |
1958 | } else if (mf_subvalue_intersect(&a->cmp.value, &a->cmp.mask, | |
1959 | &b->cmp.value, &b->cmp.mask, | |
1960 | &b->cmp.value, &b->cmp.mask)) { | |
1961 | list_remove(&a->node); | |
1962 | expr_destroy(a); | |
1963 | } else { | |
1964 | expr_destroy(expr); | |
1965 | return expr_create_boolean(false); | |
1966 | } | |
1967 | } | |
1968 | if (list_is_short(&expr->andor)) { | |
1969 | struct expr *sub = expr_from_node(list_front(&expr->andor)); | |
1970 | free(expr); | |
1971 | return sub; | |
1972 | } | |
1973 | ||
1974 | struct expr *sub; | |
1975 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
1976 | if (sub->type == EXPR_T_CMP) { | |
1977 | continue; | |
1978 | } | |
1979 | ||
1980 | ovs_assert(sub->type == EXPR_T_OR); | |
1981 | const struct expr_symbol *symbol = expr_is_cmp(sub); | |
1982 | if (!symbol || symbol->must_crossproduct) { | |
1983 | struct expr *or = expr_create_andor(EXPR_T_OR); | |
1984 | struct expr *k; | |
1985 | ||
1986 | LIST_FOR_EACH (k, node, &sub->andor) { | |
1987 | struct expr *and = expr_create_andor(EXPR_T_AND); | |
1988 | struct expr *m; | |
1989 | ||
1990 | LIST_FOR_EACH (m, node, &expr->andor) { | |
1991 | struct expr *term = m == sub ? k : m; | |
1992 | if (term->type == EXPR_T_AND) { | |
1993 | struct expr *p; | |
1994 | ||
1995 | LIST_FOR_EACH (p, node, &term->andor) { | |
1996 | struct expr *new = expr_clone(p); | |
1997 | list_push_back(&and->andor, &new->node); | |
1998 | } | |
1999 | } else { | |
2000 | struct expr *new = expr_clone(term); | |
2001 | list_push_back(&and->andor, &new->node); | |
2002 | } | |
2003 | } | |
2004 | list_push_back(&or->andor, &and->node); | |
2005 | } | |
2006 | expr_destroy(expr); | |
2007 | return expr_normalize_or(or); | |
2008 | } | |
2009 | } | |
2010 | return expr; | |
2011 | } | |
2012 | ||
2013 | static struct expr * | |
2014 | expr_normalize_or(struct expr *expr) | |
2015 | { | |
2016 | struct expr *sub, *next; | |
2017 | ||
2018 | LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) { | |
2019 | if (sub->type == EXPR_T_AND) { | |
2020 | list_remove(&sub->node); | |
2021 | ||
2022 | struct expr *new = expr_normalize_and(sub); | |
2023 | if (new->type == EXPR_T_BOOLEAN) { | |
2024 | if (new->boolean) { | |
2025 | expr_destroy(expr); | |
2026 | return new; | |
2027 | } | |
2028 | free(new); | |
2029 | } else { | |
2030 | expr_insert_andor(expr, next, new); | |
2031 | } | |
2032 | } else { | |
2033 | ovs_assert(sub->type == EXPR_T_CMP); | |
2034 | } | |
2035 | } | |
2036 | if (list_is_empty(&expr->andor)) { | |
2037 | free(expr); | |
2038 | return expr_create_boolean(false); | |
2039 | } | |
2040 | if (list_is_short(&expr->andor)) { | |
2041 | struct expr *sub = expr_from_node(list_pop_front(&expr->andor)); | |
2042 | free(expr); | |
2043 | return sub; | |
2044 | } | |
2045 | ||
2046 | return expr; | |
2047 | } | |
2048 | ||
2049 | /* Takes ownership of 'expr', which is either a constant "true" or "false" or | |
2050 | * an expression in terms of only relationals, AND, and OR. Returns either a | |
2051 | * constant "true" or "false" or 'expr' reduced to OR(AND(clause)) where a | |
2052 | * clause is a cmp or a disjunction of cmps on a single field. This form is | |
2053 | * significant because it is a form that can be directly converted to OpenFlow | |
2054 | * flows with the Open vSwitch "conjunctive match" extension. | |
2055 | * | |
2056 | * 'expr' must already have been simplified, with expr_simplify(). */ | |
2057 | struct expr * | |
2058 | expr_normalize(struct expr *expr) | |
2059 | { | |
2060 | switch (expr->type) { | |
2061 | case EXPR_T_CMP: | |
2062 | return expr; | |
2063 | ||
2064 | case EXPR_T_AND: | |
2065 | return expr_normalize_and(expr); | |
2066 | ||
2067 | case EXPR_T_OR: | |
2068 | return expr_normalize_or(expr); | |
2069 | ||
2070 | case EXPR_T_BOOLEAN: | |
2071 | return expr; | |
2072 | } | |
2073 | OVS_NOT_REACHED(); | |
2074 | } | |
2075 | \f | |
2076 | /* Creates, initializes, and returns a new 'struct expr_match'. If 'm' is | |
2077 | * nonnull then it is copied into the new expr_match, otherwise the new | |
2078 | * expr_match's 'match' member is initialized to a catch-all match for the | |
2079 | * caller to refine in-place. | |
2080 | * | |
2081 | * If 'conj_id' is nonzero, adds one conjunction based on 'conj_id', 'clause', | |
2082 | * and 'n_clauses' to the returned 'struct expr_match', otherwise the | |
2083 | * expr_match will not have any conjunctions. | |
2084 | * | |
2085 | * The caller should use expr_match_add() to add the expr_match to a hash table | |
2086 | * after it is finalized. */ | |
2087 | static struct expr_match * | |
2088 | expr_match_new(const struct match *m, uint8_t clause, uint8_t n_clauses, | |
2089 | uint32_t conj_id) | |
2090 | { | |
2091 | struct expr_match *match = xmalloc(sizeof *match); | |
2092 | if (m) { | |
2093 | match->match = *m; | |
2094 | } else { | |
2095 | match_init_catchall(&match->match); | |
2096 | } | |
2097 | if (conj_id) { | |
2098 | match->conjunctions = xmalloc(sizeof *match->conjunctions); | |
2099 | match->conjunctions[0].id = conj_id; | |
2100 | match->conjunctions[0].clause = clause; | |
2101 | match->conjunctions[0].n_clauses = n_clauses; | |
2102 | match->n = 1; | |
2103 | match->allocated = 1; | |
2104 | } else { | |
2105 | match->conjunctions = NULL; | |
2106 | match->n = 0; | |
2107 | match->allocated = 0; | |
2108 | } | |
2109 | return match; | |
2110 | } | |
2111 | ||
2112 | /* Adds 'match' to hash table 'matches', which becomes the new owner of | |
2113 | * 'match'. | |
2114 | * | |
2115 | * This might actually destroy 'match' because it gets merged together with | |
2116 | * some existing conjunction.*/ | |
2117 | static void | |
2118 | expr_match_add(struct hmap *matches, struct expr_match *match) | |
2119 | { | |
2120 | uint32_t hash = match_hash(&match->match, 0); | |
2121 | struct expr_match *m; | |
2122 | ||
2123 | HMAP_FOR_EACH_WITH_HASH (m, hmap_node, hash, matches) { | |
2124 | if (match_equal(&m->match, &match->match)) { | |
2125 | if (!m->n || !match->n) { | |
2126 | free(m->conjunctions); | |
2127 | m->conjunctions = NULL; | |
2128 | m->n = 0; | |
2129 | m->allocated = 0; | |
2130 | } else { | |
2131 | ovs_assert(match->n == 1); | |
2132 | if (m->n >= m->allocated) { | |
2133 | m->conjunctions = x2nrealloc(m->conjunctions, | |
2134 | &m->allocated, | |
2135 | sizeof *m->conjunctions); | |
2136 | } | |
2137 | m->conjunctions[m->n++] = match->conjunctions[0]; | |
2138 | } | |
2139 | free(match->conjunctions); | |
2140 | free(match); | |
2141 | return; | |
2142 | } | |
2143 | } | |
2144 | ||
2145 | hmap_insert(matches, &match->hmap_node, hash); | |
2146 | } | |
2147 | ||
f386a8a7 BP |
2148 | static bool |
2149 | constrain_match(const struct expr *expr, const struct simap *ports, | |
2150 | struct match *m) | |
e0840f11 BP |
2151 | { |
2152 | ovs_assert(expr->type == EXPR_T_CMP); | |
f386a8a7 BP |
2153 | if (expr->cmp.symbol->width) { |
2154 | mf_mask_subfield(expr->cmp.symbol->field, &expr->cmp.value, | |
2155 | &expr->cmp.mask, m); | |
2156 | } else { | |
2157 | const struct simap_node *node; | |
2158 | node = ports ? simap_find(ports, expr->cmp.string) : NULL; | |
2159 | if (!node) { | |
2160 | return false; | |
2161 | } | |
2162 | ||
2163 | struct mf_subfield sf; | |
2164 | sf.field = expr->cmp.symbol->field; | |
2165 | sf.ofs = 0; | |
2166 | sf.n_bits = expr->cmp.symbol->field->n_bits; | |
2167 | ||
2168 | union mf_subvalue x; | |
2169 | memset(&x, 0, sizeof x); | |
2170 | x.integer = htonll(node->data); | |
2171 | ||
2172 | mf_write_subfield(&sf, &x, m); | |
2173 | } | |
2174 | return true; | |
e0840f11 BP |
2175 | } |
2176 | ||
f386a8a7 BP |
2177 | static bool |
2178 | add_disjunction(const struct expr *or, const struct simap *ports, | |
2179 | struct match *m, uint8_t clause, uint8_t n_clauses, | |
2180 | uint32_t conj_id, struct hmap *matches) | |
e0840f11 BP |
2181 | { |
2182 | struct expr *sub; | |
f386a8a7 | 2183 | int n = 0; |
e0840f11 BP |
2184 | |
2185 | ovs_assert(or->type == EXPR_T_OR); | |
2186 | LIST_FOR_EACH (sub, node, &or->andor) { | |
2187 | struct expr_match *match = expr_match_new(m, clause, n_clauses, | |
2188 | conj_id); | |
f386a8a7 BP |
2189 | if (constrain_match(sub, ports, &match->match)) { |
2190 | expr_match_add(matches, match); | |
2191 | n++; | |
2192 | } else { | |
2193 | free(match->conjunctions); | |
2194 | free(match); | |
2195 | } | |
e0840f11 | 2196 | } |
f386a8a7 BP |
2197 | |
2198 | /* If n == 1, then this didn't really need to be a disjunction. Oh well, | |
2199 | * that shouldn't happen much. */ | |
2200 | return n > 0; | |
e0840f11 BP |
2201 | } |
2202 | ||
2203 | static void | |
f386a8a7 BP |
2204 | add_conjunction(const struct expr *and, const struct simap *ports, |
2205 | uint32_t *n_conjsp, struct hmap *matches) | |
e0840f11 BP |
2206 | { |
2207 | struct match match; | |
2208 | int n_clauses = 0; | |
2209 | struct expr *sub; | |
2210 | ||
2211 | match_init_catchall(&match); | |
2212 | ||
2213 | ovs_assert(and->type == EXPR_T_AND); | |
2214 | LIST_FOR_EACH (sub, node, &and->andor) { | |
2215 | switch (sub->type) { | |
2216 | case EXPR_T_CMP: | |
f386a8a7 BP |
2217 | if (!constrain_match(sub, ports, &match)) { |
2218 | return; | |
2219 | } | |
e0840f11 BP |
2220 | break; |
2221 | case EXPR_T_OR: | |
2222 | n_clauses++; | |
2223 | break; | |
2224 | case EXPR_T_AND: | |
2225 | case EXPR_T_BOOLEAN: | |
2226 | OVS_NOT_REACHED(); | |
2227 | } | |
2228 | } | |
2229 | ||
2230 | if (!n_clauses) { | |
2231 | expr_match_add(matches, expr_match_new(&match, 0, 0, 0)); | |
2232 | } else if (n_clauses == 1) { | |
2233 | LIST_FOR_EACH (sub, node, &and->andor) { | |
2234 | if (sub->type == EXPR_T_OR) { | |
f386a8a7 | 2235 | add_disjunction(sub, ports, &match, 0, 0, 0, matches); |
e0840f11 BP |
2236 | } |
2237 | } | |
2238 | } else { | |
2239 | int clause = 0; | |
2240 | (*n_conjsp)++; | |
2241 | LIST_FOR_EACH (sub, node, &and->andor) { | |
2242 | if (sub->type == EXPR_T_OR) { | |
f386a8a7 BP |
2243 | if (!add_disjunction(sub, ports, &match, clause++, |
2244 | n_clauses, *n_conjsp, matches)) { | |
2245 | /* This clause can't ever match, so we might as well skip | |
2246 | * adding the other clauses--the overall disjunctive flow | |
2247 | * can't ever match. Ideally we would also back out all of | |
2248 | * the clauses we already added, but that seems like a lot | |
2249 | * of trouble for a case that might never occur in | |
2250 | * practice. */ | |
2251 | return; | |
2252 | } | |
e0840f11 BP |
2253 | } |
2254 | } | |
2255 | } | |
2256 | } | |
2257 | ||
2258 | static void | |
f386a8a7 BP |
2259 | add_cmp_flow(const struct expr *cmp, const struct simap *ports, |
2260 | struct hmap *matches) | |
e0840f11 BP |
2261 | { |
2262 | struct expr_match *m = expr_match_new(NULL, 0, 0, 0); | |
f386a8a7 BP |
2263 | if (constrain_match(cmp, ports, &m->match)) { |
2264 | expr_match_add(matches, m); | |
2265 | } else { | |
2266 | free(m); | |
2267 | } | |
e0840f11 BP |
2268 | } |
2269 | ||
2270 | /* Converts 'expr', which must be in the form returned by expr_normalize(), to | |
2271 | * a collection of Open vSwitch flows in 'matches', which this function | |
f386a8a7 BP |
2272 | * initializes to an hmap of "struct expr_match" structures. Returns the |
2273 | * number of conjunctive match IDs consumed by 'matches', which uses | |
2274 | * conjunctive match IDs beginning with 0; the caller must offset or remap them | |
2275 | * into the desired range as necessary. | |
2276 | * | |
2277 | * 'ports' must be a map from strings (presumably names of ports) to integers. | |
2278 | * Any comparisons against string fields in 'expr' are translated into integers | |
2279 | * through this map. A comparison against a string that is not in 'ports' acts | |
2280 | * like a Boolean "false"; that is, it will always fail to match. For a simple | |
2281 | * expression, this means that the overall expression always fails to match, | |
2282 | * but an expression with a disjunction on the string field might still match | |
2283 | * on other port names. | |
2284 | * | |
2285 | * (This treatment of string fields might be too simplistic in general, but it | |
2286 | * seems reasonable for now when string fields are used only for ports.) */ | |
e0840f11 | 2287 | uint32_t |
f386a8a7 BP |
2288 | expr_to_matches(const struct expr *expr, const struct simap *ports, |
2289 | struct hmap *matches) | |
e0840f11 BP |
2290 | { |
2291 | uint32_t n_conjs = 0; | |
2292 | ||
2293 | hmap_init(matches); | |
2294 | switch (expr->type) { | |
2295 | case EXPR_T_CMP: | |
f386a8a7 | 2296 | add_cmp_flow(expr, ports, matches); |
e0840f11 BP |
2297 | break; |
2298 | ||
2299 | case EXPR_T_AND: | |
f386a8a7 | 2300 | add_conjunction(expr, ports, &n_conjs, matches); |
e0840f11 BP |
2301 | break; |
2302 | ||
2303 | case EXPR_T_OR: | |
2304 | if (expr_is_cmp(expr)) { | |
2305 | struct expr *sub; | |
2306 | ||
2307 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
f386a8a7 | 2308 | add_cmp_flow(sub, ports, matches); |
e0840f11 BP |
2309 | } |
2310 | } else { | |
2311 | struct expr *sub; | |
2312 | ||
2313 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
2314 | if (sub->type == EXPR_T_AND) { | |
f386a8a7 | 2315 | add_conjunction(sub, ports, &n_conjs, matches); |
e0840f11 | 2316 | } else { |
f386a8a7 | 2317 | add_cmp_flow(sub, ports, matches); |
e0840f11 BP |
2318 | } |
2319 | } | |
2320 | } | |
2321 | break; | |
2322 | ||
2323 | case EXPR_T_BOOLEAN: | |
2324 | if (expr->boolean) { | |
2325 | struct expr_match *m = expr_match_new(NULL, 0, 0, 0); | |
2326 | expr_match_add(matches, m); | |
2327 | } else { | |
2328 | /* No match. */ | |
2329 | } | |
2330 | break; | |
2331 | } | |
2332 | return n_conjs; | |
2333 | } | |
f386a8a7 BP |
2334 | |
2335 | /* Destroys all of the 'struct expr_match'es in 'matches', as well as the | |
2336 | * 'matches' hmap itself. */ | |
2337 | void | |
2338 | expr_matches_destroy(struct hmap *matches) | |
2339 | { | |
2340 | struct expr_match *m, *n; | |
2341 | ||
2342 | HMAP_FOR_EACH_SAFE (m, n, hmap_node, matches) { | |
2343 | hmap_remove(matches, &m->hmap_node); | |
2344 | free(m->conjunctions); | |
2345 | free(m); | |
2346 | } | |
2347 | hmap_destroy(matches); | |
2348 | } | |
2349 | ||
2350 | /* Prints a representation of the 'struct expr_match'es in 'matches' to | |
2351 | * 'stream'. */ | |
2352 | void | |
2353 | expr_matches_print(const struct hmap *matches, FILE *stream) | |
2354 | { | |
2355 | if (hmap_is_empty(matches)) { | |
2356 | fputs("(no flows)\n", stream); | |
2357 | return; | |
2358 | } | |
2359 | ||
2360 | const struct expr_match *m; | |
2361 | HMAP_FOR_EACH (m, hmap_node, matches) { | |
2362 | char *s = match_to_string(&m->match, OFP_DEFAULT_PRIORITY); | |
2363 | fputs(s, stream); | |
2364 | free(s); | |
2365 | ||
2366 | if (m->n) { | |
2367 | for (int i = 0; i < m->n; i++) { | |
2368 | const struct cls_conjunction *c = &m->conjunctions[i]; | |
2369 | fprintf(stream, "%c conjunction(%"PRIu32", %d/%d)", | |
2370 | i == 0 ? ':' : ',', c->id, c->clause, c->n_clauses); | |
2371 | } | |
2372 | } | |
2373 | putc('\n', stream); | |
2374 | } | |
2375 | } | |
e0840f11 BP |
2376 | \f |
2377 | /* Returns true if 'expr' honors the invariants for expressions (see the large | |
2378 | * comment above "struct expr" in expr.h), false otherwise. */ | |
2379 | bool | |
2380 | expr_honors_invariants(const struct expr *expr) | |
2381 | { | |
2382 | const struct expr *sub; | |
2383 | ||
2384 | switch (expr->type) { | |
2385 | case EXPR_T_CMP: | |
2386 | if (expr->cmp.symbol->width) { | |
2387 | for (int i = 0; i < ARRAY_SIZE(expr->cmp.value.be64); i++) { | |
2388 | if (expr->cmp.value.be64[i] & ~expr->cmp.mask.be64[i]) { | |
2389 | return false; | |
2390 | } | |
2391 | } | |
2392 | } | |
2393 | return true; | |
2394 | ||
2395 | case EXPR_T_AND: | |
2396 | case EXPR_T_OR: | |
2397 | if (list_is_short(&expr->andor)) { | |
2398 | return false; | |
2399 | } | |
2400 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
2401 | if (sub->type == expr->type || !expr_honors_invariants(sub)) { | |
2402 | return false; | |
2403 | } | |
2404 | } | |
2405 | return true; | |
2406 | ||
2407 | case EXPR_T_BOOLEAN: | |
2408 | return true; | |
2409 | ||
2410 | default: | |
2411 | OVS_NOT_REACHED(); | |
2412 | } | |
2413 | } | |
2414 | ||
2415 | static bool | |
2416 | expr_is_normalized_and(const struct expr *expr) | |
2417 | { | |
2418 | /* XXX should also check that no symbol is repeated. */ | |
2419 | const struct expr *sub; | |
2420 | ||
2421 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
2422 | if (!expr_is_cmp(sub)) { | |
2423 | return false; | |
2424 | } | |
2425 | } | |
2426 | return true; | |
2427 | } | |
2428 | ||
2429 | /* Returns true if 'expr' is in the form returned by expr_normalize(), false | |
2430 | * otherwise. */ | |
2431 | bool | |
2432 | expr_is_normalized(const struct expr *expr) | |
2433 | { | |
2434 | switch (expr->type) { | |
2435 | case EXPR_T_CMP: | |
2436 | return true; | |
2437 | ||
2438 | case EXPR_T_AND: | |
2439 | return expr_is_normalized_and(expr); | |
2440 | ||
2441 | case EXPR_T_OR: | |
2442 | if (!expr_is_cmp(expr)) { | |
2443 | const struct expr *sub; | |
2444 | ||
2445 | LIST_FOR_EACH (sub, node, &expr->andor) { | |
2446 | if (!expr_is_cmp(sub) && !expr_is_normalized_and(sub)) { | |
2447 | return false; | |
2448 | } | |
2449 | } | |
2450 | } | |
2451 | return true; | |
2452 | ||
2453 | case EXPR_T_BOOLEAN: | |
2454 | return true; | |
2455 | ||
2456 | default: | |
2457 | OVS_NOT_REACHED(); | |
2458 | } | |
2459 | } |