filter.c 10.8 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 14 15 16 17 18 19 20 21
 */

#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"
22
#include "lib/string.h"
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "conf/conf.h"
#include "filter/filter.h"

struct f_inst *startup_func = NULL;

#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); \
	if (x.type == T_RETURN) \
		return x;

Pavel Machek's avatar
Pavel Machek committed
43 44 45
#define ONEARG ARG(v1, a1.p)
#define TWOARGS ARG(v1, a1.p) \
		ARG(v2, a2.p)
46 47 48 49
#define TWOARGS_C TWOARGS \
                  if (v1.type != v2.type) \
		    runtime( "Can not operate with values of incompatible types" );

50 51 52 53 54 55
#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
56 57 58 59 60 61 62
  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;

63 64
  if (v1.type != v2.type)
    return CMP_ERROR;
65
  switch (v1.type) {
66
  case T_ENUM:
67
  case T_INT: 
68
  case T_PAIR:
69 70 71
    if (v1.val.i == v2.val.i) return 0;
    if (v1.val.i < v2.val.i) return -1;
    return 1;
72
  case T_IP:
73 74
  case T_PREFIX:
    return ipa_compare(v1.val.px.ip, v2.val.px.ip);
Pavel Machek's avatar
Pavel Machek committed
75
  default: { printf( "Error comparing\n" ); return CMP_ERROR; }
76 77 78
  }
}

79 80 81 82 83 84 85 86 87 88 89 90 91
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;
92

93 94 95 96 97 98 99 100 101 102 103 104
    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;
}

105 106 107
int
val_in_range(struct f_val v1, struct f_val v2)
{
108 109 110 111 112 113 114
  int res;

  res = val_simple_in_range(v1, v2);

  if (res != CMP_ERROR)
    return res;

Pavel Machek's avatar
Pavel Machek committed
115
  if (((v1.type == T_INT) || ((v1.type == T_IP) || (v1.type == T_PREFIX)) && (v2.type == T_SET))) {
116 117 118 119 120 121
    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 */
  }
122 123 124
  return CMP_ERROR;
}

125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149
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;
150
  case T_IP: PRINTF( "%I", v.val.px.ip ); break;
151 152
  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;
153
  case T_SET: tree_print( v.val.t ); PRINTF( "\n" ); break;
Pavel Machek's avatar
Pavel Machek committed
154
  case T_ENUM: PRINTF( "(enum %x)%d", v.type, v.val.i ); break;
155 156 157 158 159
  default: PRINTF( "[unknown type %x]", v.type );
  }
  printf( buf );
}

160
static struct rte **f_rte, *f_rte_old;
161
static struct linpool *f_pool;
162

163 164
static struct f_val interpret(struct f_inst *what);

165 166 167 168 169
static struct f_val
interpret(struct f_inst *what)
{
  struct symbol *sym;
  struct f_val v1, v2, res;
170
  int i,j,k;
171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202

  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 */
203 204 205 206 207 208 209 210

#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); \
211
    break;
212 213 214 215 216 217 218 219

  case '!=': COMPARE(i!=0);
  case '==': COMPARE(i==0);
  case '<': COMPARE(i==-1);
  case '<=': COMPARE(i!=1);

  case '~':
    TWOARGS;
220
    res.type = T_BOOL;
221 222 223
    res.val.i = val_in_range(v1, v2);
    if (res.val.i == CMP_ERROR)
      runtime( "~ applied on unknown type pair" );
224
    break;
225 226 227 228 229
  case 'de':
    ONEARG;
    res.type = T_BOOL;
    res.val.i = (v1.type != T_VOID);
    break;
230

231
  /* Set to indirect value, a1 = variable, a2 = value */
232
  case 's':
Pavel Machek's avatar
Pavel Machek committed
233 234
    ARG(v2, a2.p);
    sym = what->a1.p;
235 236
    switch (res.type = v2.type) {
    case T_VOID: runtime( "Can not assign void values" );
237
    case T_ENUM:
238
    case T_INT: 
239 240 241 242
    case T_IP: 
    case T_PREFIX: 
    case T_PAIR: 
      if (sym->class != (SYM_VARIABLE | v2.type))
243
	runtime( "Variable of bad type" );
244
      * (struct f_val *) sym->aux2 = v2; 
245
      break;
246 247
    default:
      bug( "Set to invalid type\n" );
248 249 250
    }
    break;

251
  case 'c':	/* integer (or simple type) constant */
252
    res.type = what->aux;
253
    res.val.i = what->a2.i;
254
    break;
255 256 257
  case 'C':
    res = * ((struct f_val *) what->a1.p);
    break;
258 259
  case 'p':
    ONEARG;
260
    val_print(v1);
261 262 263 264 265 266
    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
267
      ARG(res,a2.p);
268 269 270 271 272 273 274 275 276
      res.val.i = 0;
    } else res.val.i = 1;
    res.type = T_BOOL;
    break;
  case '0':
    printf( "No operation\n" );
    break;
  case 'p,':
    ONEARG;
277 278
    if (what->a2.i != F_NONL)
      printf( "\n" );
279

Pavel Machek's avatar
Pavel Machek committed
280
    switch (what->a2.i) {
281 282 283 284 285
    case F_QUITBIRD:
      die( "Filter asked me to die" );
    case F_ACCEPT:
      /* Should take care about turning ACCEPT into MODIFY */
    case F_ERROR:
286
    case F_REJECT:	/* FIXME (noncritical) Should print compele route along with reason to reject route */
287
      res.type = T_RETURN;
Pavel Machek's avatar
Pavel Machek committed
288
      res.val.i = what->a1.i;
289
      return res;	/* We have to return now, no more processing. */
290
    case F_NONL:
291 292 293 294 295 296
    case F_NOP:
      break;
    default:
      bug( "unknown return type: can not happen");
    }
    break;
297 298 299
  case 'a':	/* rta access */
    {
      struct rta *rta = (*f_rte)->attrs;
300
      res.type = what->aux;
301 302
      switch(res.type) {
      case T_IP:
303
	res.val.px.ip = * (ip_addr *) ((char *) rta + what->a2.i);
304
	break;
305 306 307
      case T_ENUM:
	res.val.i = * ((char *) rta + what->a2.i);
	break;
308 309 310 311 312 313 314
      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:
315
	bug( "Invalid type for rta access (%x)\n" );
316 317 318
      }
    }
    break;
319
  case 'ea':	/* Access to extended attributes [hmm, but we need it read/write, do we?] */
320 321 322 323 324 325
    {
      eattr *e = ea_find( (*f_rte)->attrs->eattrs, what->a2.i );
      if (!e) {
	res.type = T_VOID;
	break;
      }
326
      res.type = what->aux;
327 328 329 330 331 332
      switch (what->a1.i) {
      case T_INT:
	res.val.i = e->u.data;
	break;
      }
    }
333
    break;
334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351
  case 'eS':
    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;
      switch (what->aux) {
      case T_INT:
	l->attrs[0].type = EAF_TYPE_INT | EAF_INLINE;
	l->attrs[0].u.data = v1.val.i;
	break;
352 353 354 355
      case T_VOID:
	l->attrs[0].type = EAF_TYPE_UNDEF | EAF_INLINE;
	l->attrs[0].u.data = 0;
	break;
356
      }
357
      *f_rte = rte_do_cow(*f_rte);
358 359
      l->next = (*f_rte)->attrs->eattrs;
      (*f_rte)->attrs->eattrs = l;
360 361
    }
    break;
362

363 364 365 366
  case 'cp':	/* Convert prefix to ... */
    ONEARG;
    if (v1.type != T_PREFIX)
      runtime( "Can not convert non-prefix this way" );
367
    res.type = what->aux;
368 369
    switch(res.type) {
    case T_INT:	res.val.i = v1.val.px.len; break;
370
    case T_IP: res.val.px.ip = v1.val.px.ip; break;
371 372 373
    default: bug( "Unknown prefix to conversion\n" );
    }
    break;
374 375 376 377
  case 'ca': /* CALL */
    ONEARG;
    res = interpret(what->a2.p);
    break;
Pavel Machek's avatar
Pavel Machek committed
378
  case 'SW':
379
    ONEARG;
Pavel Machek's avatar
Pavel Machek committed
380 381 382 383 384 385 386 387 388 389 390 391 392 393
    {
      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);
    }
394
    break;
395
  case 'iM': /* IP.MASK(val) */
396 397 398 399 400 401 402 403 404 405
    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);
    }
406
    break;
407 408 409 410 411 412 413 414
  default:
    bug( "Unknown instruction %d (%c)", what->code, what->code & 0xff);
  }
  if (what->next)
    return interpret(what->next);
  return res;
}

415
/* FIXME: tmp_attrs is unreferenced. That can't be right */
416 417 418 419 420 421 422
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;
  debug( "Running filter `%s'...", filter->name );

423
  f_rte = rte;
424
  f_rte_old = *rte;
425
  f_pool = tmp_pool;
426 427 428 429 430 431 432 433 434 435 436 437 438
  inst = filter->root;
  res = interpret(inst);
  if (res.type != T_RETURN)
    return F_ERROR;
  debug( "done (%d)\n", res.val.i );
  return res.val.i;
}


void
filters_postconfig(void)
{
  struct f_val res;
439 440
  if (startup_func) {
    printf( "Launching startup function...\n" );
441
    res = interpret(startup_func);
Pavel Machek's avatar
Pavel Machek committed
442
    if (res.type == F_ERROR)
443 444 445
      die( "Startup function resulted in error." );
    printf( "done\n" );
  }
446
}