filter.c 13.6 KB
Newer Older
1 2 3 4 5 6
/*
 *	Filters: utility functions
 *
 *	Copyright 1998 Pavel Machek <pavel@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
7
 *
8
 * 	Notice that pair is stored as integer: first << 16 | second
Pavel Machek's avatar
Pavel Machek committed
9
 *
10 11
 */

12 13
#undef LOCAL_DEBUG

14 15 16 17 18 19 20 21 22 23
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/signal.h>
#include <setjmp.h>

#include "nest/bird.h"
#include "lib/lists.h"
#include "lib/resource.h"
#include "lib/socket.h"
24
#include "lib/string.h"
25 26 27 28 29 30
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "conf/conf.h"
#include "filter/filter.h"

31 32
#define P(a,b) ((a<<8) | b)

33 34
struct f_inst *startup_func = NULL;

35 36 37 38 39 40
#define CMP_ERROR 999

/* Compare two values, returns -1, 0, 1 compared, ERROR 999 */
int
val_compare(struct f_val v1, struct f_val v2)
{
Pavel Machek's avatar
Pavel Machek committed
41 42 43 44 45 46 47
  if ((v1.type == T_VOID) && (v2.type == T_VOID))
    return 0;
  if (v1.type == T_VOID)	/* Hack for else */
    return -1;
  if (v2.type == T_VOID)
    return 1;

48 49
  if (v1.type != v2.type)
    return CMP_ERROR;
50
  switch (v1.type) {
51
  case T_ENUM:
52
  case T_INT: 
53
  case T_PAIR:
54 55 56
    if (v1.val.i == v2.val.i) return 0;
    if (v1.val.i < v2.val.i) return -1;
    return 1;
57
  case T_IP:
58 59
  case T_PREFIX:
    return ipa_compare(v1.val.px.ip, v2.val.px.ip);
Pavel Machek's avatar
Pavel Machek committed
60
  default: { printf( "Error comparing\n" ); return CMP_ERROR; }
61 62 63
  }
}

64 65 66 67 68 69 70 71 72 73 74 75 76
int 
val_simple_in_range(struct f_val v1, struct f_val v2)
{
  if ((v1.type == T_IP) && (v2.type == T_PREFIX))
    return !(ipa_compare(ipa_and(v2.val.px.ip, ipa_mkmask(v2.val.px.len)), ipa_and(v1.val.px.ip, ipa_mkmask(v2.val.px.len))));

  if ((v1.type == T_PREFIX) && (v2.type == T_PREFIX)) {
    ip_addr mask;
    if (v1.val.px.len & (LEN_PLUS | LEN_MINUS | LEN_RANGE))
      return CMP_ERROR;
    mask = ipa_mkmask( v2.val.px.len & LEN_MASK );
    if (ipa_compare(ipa_and(v2.val.px.ip, mask), ipa_and(v1.val.px.ip, mask)))
      return 0;
77

78 79 80 81 82 83 84 85 86 87 88 89
    if ((v2.val.px.len & LEN_MINUS) && (v1.val.px.len <= (v2.val.px.len & LEN_MASK)))
      return 0;
    if ((v2.val.px.len & LEN_PLUS) && (v1.val.px.len < (v2.val.px.len & LEN_MASK)))
      return 0;
    if ((v2.val.px.len & LEN_RANGE) && ((v1.val.px.len < (0xff & (v2.val.px.len >> 16)))
					|| (v1.val.px.len > (0xff & (v2.val.px.len >> 8)))))
      return 0;
    return 1;    
  }
  return CMP_ERROR;
}

90 91 92
int
val_in_range(struct f_val v1, struct f_val v2)
{
93 94 95 96 97 98 99
  int res;

  res = val_simple_in_range(v1, v2);

  if (res != CMP_ERROR)
    return res;

Pavel Machek's avatar
Pavel Machek committed
100
  if (((v1.type == T_INT) || ((v1.type == T_IP) || (v1.type == T_PREFIX)) && (v2.type == T_SET))) {
101 102 103 104 105 106
    struct f_tree *n;
    n = find_tree(v2.val.t, v1);
    if (!n)
      return 0;
    return !! (val_simple_in_range(v1, n->from));	/* We turn CMP_ERROR into compared ok, and that's fine */
  }
107 108 109
  return CMP_ERROR;
}

110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134
static void
tree_print(struct f_tree *t)
{
  if (!t) {
    printf( "() " );
    return;
  }
  printf( "[ " );
  tree_print( t->left );
  printf( ", " ); val_print( t->from ); printf( ".." ); val_print( t->to ); printf( ", " );
  tree_print( t->right );
  printf( "] " );
}

void
val_print(struct f_val v)
{
  char buf[2048];
#define PRINTF(a...) bsnprintf( buf, 2040, a )
  buf[0] = 0;
  switch (v.type) {
  case T_VOID: PRINTF( "(void)" ); break;
  case T_BOOL: PRINTF( v.val.i ? "TRUE" : "FALSE" ); break;
  case T_INT: PRINTF( "%d ", v.val.i ); break;
  case T_STRING: PRINTF( "%s", v.val.s ); break;
135
  case T_IP: PRINTF( "%I", v.val.px.ip ); break;
136 137
  case T_PREFIX: PRINTF( "%I/%d", v.val.px.ip, v.val.px.len ); break;
  case T_PAIR: PRINTF( "(%d,%d)", v.val.i >> 16, v.val.i & 0xffff ); break;
138
  case T_SET: tree_print( v.val.t ); PRINTF( "\n" ); break;
Pavel Machek's avatar
Pavel Machek committed
139
  case T_ENUM: PRINTF( "(enum %x)%d", v.type, v.val.i ); break;
140 141 142 143 144
  default: PRINTF( "[unknown type %x]", v.type );
  }
  printf( buf );
}

145
static struct rte **f_rte, *f_rte_old;
146
static struct linpool *f_pool;
Pavel Machek's avatar
Pavel Machek committed
147
static struct ea_list **f_tmp_attrs;
148

149 150 151 152 153 154 155 156 157
#define runtime(x) do { \
    log( L_ERR x ); \
    res.type = T_RETURN; \
    res.val.i = F_ERROR; \
    return res; \
  } while(0)

#define ARG(x,y) \
	x = interpret(what->y); \
158
	if (x.type & T_RETURN) \
159 160 161 162 163 164 165 166
		return x;

#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
		ARG(v2, a2.p)
#define TWOARGS_C TWOARGS \
                  if (v1.type != v2.type) \
		    runtime( "Can not operate with values of incompatible types" );
167

168 169 170 171 172
static struct f_val
interpret(struct f_inst *what)
{
  struct symbol *sym;
  struct f_val v1, v2, res;
173
  int i,j,k;
174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205

  res.type = T_VOID;
  if (!what)
    return res;

  switch(what->code) {
  case ',':
    TWOARGS;
    break;

/* Binary operators */
  case '+':
    TWOARGS_C;
    switch (res.type = v1.type) {
    case T_VOID: runtime( "Can not operate with values of type void" );
    case T_INT: res.val.i = v1.val.i + v2.val.i; break;
    default: runtime( "Usage of unknown type" );
    }
    break;
  case '/':
    TWOARGS_C;
    switch (res.type = v1.type) {
    case T_VOID: runtime( "Can not operate with values of type void" );
    case T_INT: res.val.i = v1.val.i / v2.val.i; break;
    case T_IP: if (v2.type != T_INT)
                 runtime( "Operator / is <ip>/<int>" );
               break;
    default: runtime( "Usage of unknown type" );
    }
    break;

/* Relational operators */
206 207 208 209 210 211 212 213

#define COMPARE(x) \
    TWOARGS_C; \
    res.type = T_BOOL; \
    i = val_compare(v1, v2); \
    if (i==CMP_ERROR) \
      runtime( "Error in comparation" ); \
    res.val.i = (x); \
214
    break;
215

216 217
  case P('!','='): COMPARE(i!=0);
  case P('=','='): COMPARE(i==0);
218
  case '<': COMPARE(i==-1);
219
  case P('<','='): COMPARE(i!=1);
220

Pavel Machek's avatar
Pavel Machek committed
221 222 223 224 225 226 227 228
  case '!':
    ONEARG;
    if (v1.type != T_BOOL)
      runtime( "not applied to non-boolean" );
    res = v1;
    res.val.i = !res.val.i;
    break;

229 230
  case '~':
    TWOARGS;
231
    res.type = T_BOOL;
232 233 234
    res.val.i = val_in_range(v1, v2);
    if (res.val.i == CMP_ERROR)
      runtime( "~ applied on unknown type pair" );
235
    break;
236
  case P('d','e'):
237 238 239 240
    ONEARG;
    res.type = T_BOOL;
    res.val.i = (v1.type != T_VOID);
    break;
241

242
  /* Set to indirect value, a1 = variable, a2 = value */
243
  case 's':
Pavel Machek's avatar
Pavel Machek committed
244 245
    ARG(v2, a2.p);
    sym = what->a1.p;
246 247
    switch (res.type = v2.type) {
    case T_VOID: runtime( "Can not assign void values" );
248
    case T_ENUM:
249
    case T_INT: 
250 251 252 253
    case T_IP: 
    case T_PREFIX: 
    case T_PAIR: 
      if (sym->class != (SYM_VARIABLE | v2.type))
254
	runtime( "Variable of bad type" );
255
      * (struct f_val *) sym->aux2 = v2; 
256
      break;
257 258
    default:
      bug( "Set to invalid type\n" );
259 260 261
    }
    break;

262
  case 'c':	/* integer (or simple type) constant */
263
    res.type = what->aux;
264
    res.val.i = what->a2.i;
265
    break;
266 267 268
  case 'C':
    res = * ((struct f_val *) what->a1.p);
    break;
269 270
  case 'p':
    ONEARG;
271
    val_print(v1);
272 273 274 275 276 277
    break;
  case '?':	/* ? has really strange error value, so we can implement if ... else nicely :-) */
    ONEARG;
    if (v1.type != T_BOOL)
      runtime( "If requires bool expression" );
    if (v1.val.i) {
Pavel Machek's avatar
Pavel Machek committed
278
      ARG(res,a2.p);
279 280 281 282 283 284 285
      res.val.i = 0;
    } else res.val.i = 1;
    res.type = T_BOOL;
    break;
  case '0':
    printf( "No operation\n" );
    break;
286
  case P('p',','):
287
    ONEARG;
288 289
    if (what->a2.i != F_NONL)
      printf( "\n" );
290

Pavel Machek's avatar
Pavel Machek committed
291
    switch (what->a2.i) {
292 293 294 295 296
    case F_QUITBIRD:
      die( "Filter asked me to die" );
    case F_ACCEPT:
      /* Should take care about turning ACCEPT into MODIFY */
    case F_ERROR:
297
    case F_REJECT:	/* FIXME (noncritical) Should print complete route along with reason to reject route */
298
      res.type = T_RETURN;
299
      res.val.i = what->a2.i;
300
      return res;	/* We have to return now, no more processing. */
301
    case F_NONL:
302 303 304 305 306 307
    case F_NOP:
      break;
    default:
      bug( "unknown return type: can not happen");
    }
    break;
308 309 310
  case 'a':	/* rta access */
    {
      struct rta *rta = (*f_rte)->attrs;
311
      res.type = what->aux;
312 313
      switch(res.type) {
      case T_IP:
314
	res.val.px.ip = * (ip_addr *) ((char *) rta + what->a2.i);
315
	break;
316 317 318
      case T_ENUM:
	res.val.i = * ((char *) rta + what->a2.i);
	break;
319 320 321 322 323 324 325
      case T_PREFIX:	/* Warning: this works only for prefix of network */
	{
	  res.val.px.ip = (*f_rte)->net->n.prefix;
	  res.val.px.len = (*f_rte)->net->n.pxlen;
	  break;
	}
      default:
326
	bug( "Invalid type for rta access (%x)\n" );
327 328 329
      }
    }
    break;
330
  case P('e','a'):	/* Access to extended attributes */
331 332
    {
      eattr *e = ea_find( (*f_rte)->attrs->eattrs, what->a2.i );
Pavel Machek's avatar
Pavel Machek committed
333 334
      if (!e) 
	e = ea_find( (*f_tmp_attrs), what->a2.i );
335 336 337 338
      if (!e) {
	res.type = T_VOID;
	break;
      }
339
      res.type = what->aux;
340 341 342 343 344 345
      switch (what->a1.i) {
      case T_INT:
	res.val.i = e->u.data;
	break;
      }
    }
346
    break;
347
  case P('e','S'):
348 349 350 351 352 353 354 355 356 357 358 359
    ONEARG;
    if (v1.type != what->aux)
      runtime("Wrong type when setting dynamic attribute\n");

    {
      struct ea_list *l = lp_alloc(f_pool, sizeof(struct ea_list) + sizeof(eattr));

      l->next = NULL;
      l->flags = EALF_SORTED;
      l->count = 1;
      l->attrs[0].id = what->a2.i;
      l->attrs[0].flags = 0;
Pavel Machek's avatar
Pavel Machek committed
360 361 362 363 364
      l->attrs[0].type = what->aux;
      switch (what->aux & EAF_TYPE_MASK) {
      case EAF_TYPE_INT:
	if (v1.type != T_INT)
	  runtime( "Setting int attribute to non-int value" );
365 366
	l->attrs[0].u.data = v1.val.i;
	break;
Pavel Machek's avatar
Pavel Machek committed
367 368 369
      case EAF_TYPE_UNDEF:
	if (v1.type != T_VOID)
	  runtime( "Setting void attribute to non-void value" );
370 371
	l->attrs[0].u.data = 0;
	break;
372
      }
Pavel Machek's avatar
Pavel Machek committed
373

374
      if (!(what->aux & EAF_TEMP)) {
Pavel Machek's avatar
Pavel Machek committed
375 376 377 378 379 380 381
	*f_rte = rte_do_cow(*f_rte);
	l->next = (*f_rte)->attrs->eattrs;
	(*f_rte)->attrs->eattrs = l;
      } else {
	l->next = (*f_tmp_attrs);
	(*f_tmp_attrs) = l;
      }
382 383
    }
    break;
384

385
  case P('c','p'):	/* Convert prefix to ... */
386 387 388
    ONEARG;
    if (v1.type != T_PREFIX)
      runtime( "Can not convert non-prefix this way" );
389
    res.type = what->aux;
390 391
    switch(res.type) {
    case T_INT:	res.val.i = v1.val.px.len; break;
392
    case T_IP: res.val.px.ip = v1.val.px.ip; break;
393 394 395
    default: bug( "Unknown prefix to conversion\n" );
    }
    break;
396 397 398 399 400 401
  case 'r':
    ONEARG;
    res = v1;
    res.type |= T_RETURN;
    break;
  case P('c','a'): /* CALL: this is special: if T_RETURN and returning some value, mask it out  */
402 403
    ONEARG;
    res = interpret(what->a2.p);
404 405 406
    if (res.type == T_RETURN)
      return res;
    res.type &= ~T_RETURN;    
407
    break;
408
  case P('S','W'):
409
    ONEARG;
Pavel Machek's avatar
Pavel Machek committed
410 411 412 413 414 415 416 417 418 419 420 421 422 423
    {
      struct f_tree *t = find_tree(what->a2.p, v1);
      if (!t) {
	v1.type = T_VOID;
	t = find_tree(what->a2.p, v1);
	if (!t) {
	  printf( "No else statement?\n ");
	  break;
	}
      }	
      if (!t->data)
	die( "Impossible: no code associated!\n" );
      return interpret(t->data);
    }
424
    break;
425
  case P('i','M'): /* IP.MASK(val) */
426 427 428 429 430 431 432 433 434 435
    TWOARGS;
    if (v2.type != T_INT)
      runtime( "Can not use this type for mask.");
    if (v1.type != T_IP)
      runtime( "You can mask only IP addresses." );
    {
      ip_addr mask = ipa_mkmask(v2.val.i);
      res.type = T_IP;
      res.val.px.ip = ipa_and(mask, v1.val.px.ip);
    }
436
    break;
437 438 439 440 441 442 443 444
  default:
    bug( "Unknown instruction %d (%c)", what->code, what->code & 0xff);
  }
  if (what->next)
    return interpret(what->next);
  return res;
}

445
#undef ARG
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460
#define ARG(x,y) \
	if (!i_same(f1->y, f2->y)) \
		return 0;

#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
		ARG(v2, a2.p)

#define A2_SAME if (f1->a2.i != f2->a2.i) return 0;

int
i_same(struct f_inst *f1, struct f_inst *f2)
{
  if ((!!f1) != (!!f2))
    return 0;
461 462
  if (!f1)
    return 1;
463 464 465 466
  if (f1->aux != f2->aux)
    return 0;
  if (f1->code != f2->code)
    return 0;
467 468
  if (f1 == f2)		/* It looks strange, but it is possible with call rewriting trickery */
    return 1;
469 470 471 472 473

  switch(f1->code) {
  case ',': /* fall through */
  case '+':
  case '/':
474 475
  case P('!','='):
  case P('=','='):
476
  case '<':
477
  case P('<','='): TWOARGS; break;
478

Pavel Machek's avatar
Pavel Machek committed
479
  case '!': ONEARG; break;
480
  case '~': TWOARGS; break;
481
  case P('d','e'): ONEARG; break;
482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503

  case 's':
    ARG(v2, a2.p);
    {
      struct symbol *s1, *s2;
      s1 = f1->a1.p;
      s2 = f2->a1.p;
      if (strcmp(s1->name, s2->name))
	return 0;
      if (s1->class != s2->class)
	return 0;
    }
    break;

  case 'c': A2_SAME; break;
  case 'C': 
    if (val_compare(* (struct f_val *) f1->a1.p, * (struct f_val *) f2->a2.p))
      return 0;
    break;
  case 'p': ONEARG; break;
  case '?': TWOARGS; break;
  case '0': break;
504
  case P('p',','): ONEARG; A2_SAME; break;
505
  case 'a': A2_SAME; break;
506 507
  case P('e','a'): A2_SAME; break;
  case P('e','S'): ONEARG; A2_SAME; break;
508

509 510
  case 'r': ONEARG; break;
  case P('c','p'): ONEARG; break;
511 512 513 514 515 516
  case P('c','a'): /* Call rewriting trickery to avoid exponential behaviour */
             ONEARG; 
	     if (!i_same(f1->a2.p, f2->a2.p))
	       return 0; 
	     f2->a2.p = f1->a2.p;
	     break;
517 518
  case P('S','W'): ONEARG; if (!same_tree(f1->a2.p, f2->a2.p)) return 0; break;
  case P('i','M'): TWOARGS; break;
519 520 521 522 523 524
  default:
    bug( "Unknown instruction %d in same (%c)", f1->code, f1->code & 0xff);
  }
  return i_same(f1->next, f2->next);
}

525 526 527 528 529
int
f_run(struct filter *filter, struct rte **rte, struct ea_list **tmp_attrs, struct linpool *tmp_pool)
{
  struct f_inst *inst;
  struct f_val res;
530
  DBG( "Running filter `%s'...", filter->name );
531

Pavel Machek's avatar
Pavel Machek committed
532
  f_tmp_attrs = tmp_attrs;
533
  f_rte = rte;
534
  f_rte_old = *rte;
535
  f_pool = tmp_pool;
536 537 538 539
  inst = filter->root;
  res = interpret(inst);
  if (res.type != T_RETURN)
    return F_ERROR;
540
  DBG( "done (%d)\n", res.val.i );
541 542 543 544 545 546 547
  return res.val.i;
}

void
filters_postconfig(void)
{
  struct f_val res;
548 549
  if (startup_func) {
    printf( "Launching startup function...\n" );
550
    res = interpret(startup_func);
Pavel Machek's avatar
Pavel Machek committed
551
    if (res.type == F_ERROR)
552 553 554
      die( "Startup function resulted in error." );
    printf( "done\n" );
  }
555
} 
556 557 558 559

int
filter_same(struct filter *new, struct filter *old)
{
560 561 562 563 564
  if (old == new)	/* Handle FILTER_ACCEPT and FILTER_REJECT */
    return 1;
  if (old == FILTER_ACCEPT || old == FILTER_REJECT ||
      new == FILTER_ACCEPT || new == FILTER_REJECT)
    return 0;
565
  return i_same(new->root, old->root);
566
}