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authorKlement Sekera <ksekera@cisco.com>2020-06-24 13:13:46 +0000
committerOle Trøan <otroan@employees.org>2020-06-25 08:58:26 +0000
commitfe77bdc1906cca6a76bd44b1aceffc971f64cec4 (patch)
tree4a10a7321e72cab239a3eacfe2778004b831c1bc /src/plugins/nat/nat_det.c
parent8eca60df745b7656b96db16e75b0deda66bfc515 (diff)
nat: avoid division by zero
Return error instead of dividing by zero. Type: fix Signed-off-by: Klement Sekera <ksekera@cisco.com> Change-Id: I9f6a942e87ab87e8f1921e744ec1add45884e74a
Diffstat (limited to 'src/plugins/nat/nat_det.c')
-rw-r--r--src/plugins/nat/nat_det.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/src/plugins/nat/nat_det.c b/src/plugins/nat/nat_det.c
index cad0d2ae5af..65a669bceb9 100644
--- a/src/plugins/nat/nat_det.c
+++ b/src/plugins/nat/nat_det.c
@@ -82,13 +82,20 @@ snat_det_add_map (snat_main_t * sm, ip4_address_t * in_addr, u8 in_plen,
num_sessions = num_sessions * 1000 - 1;
}
+ u32 sharing_ratio = (1 << (32 - in_plen)) / (1 << (32 - out_plen));
+ if (!sharing_ratio)
+ {
+ // avoid division by zero
+ return VNET_API_ERROR_INVALID_VALUE;
+ }
+
pool_get (sm->det_maps, det_map);
clib_memset (det_map, 0, sizeof (*det_map));
det_map->in_addr.as_u32 = in_cmp.as_u32;
det_map->in_plen = in_plen;
det_map->out_addr.as_u32 = out_cmp.as_u32;
det_map->out_plen = out_plen;
- det_map->sharing_ratio = (1 << (32 - in_plen)) / (1 << (32 - out_plen));
+ det_map->sharing_ratio = sharing_ratio;
det_map->ports_per_host = (65535 - 1023) / det_map->sharing_ratio;
vec_validate_init_empty (det_map->sessions, num_sessions,
id='n212' href='#n212'>212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 
/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <vlib/parse.h>

#define PARSE_DEBUG 0

u16 word_type_index, number_type_index, eof_type_index, rule_eof_type_index,
  plus_type_index, minus_type_index, star_type_index, slash_type_index,
  lpar_type_index, rpar_type_index;

u8 *
format_vlib_parse_value (u8 * s, va_list * args)
{
  vlib_parse_main_t *pm = va_arg (*args, vlib_parse_main_t *);
  vlib_parse_type_t *type;
  vlib_parse_value_t *v;
  u16 type_index;

  s = format (s, "%d items:\n", vec_len (pm->parse_value));
  vec_foreach (v, pm->parse_value)
  {
    type_index = v->type;
    type = pool_elt_at_index (pm->parse_types, type_index);
    if (type->format_value)
      s = format (s, "[%d]: %U\n", v - pm->parse_value,
		  type->format_value, v);
    else
      s = format (s, "[%d]: (nofun)\n", v - pm->parse_value);
  }
  return s;
}

static u8 *
format_vlib_parse_match (u8 * s, va_list * args)
{
  vlib_parse_match_t m = va_arg (*args, vlib_parse_match_t);
  char *t = 0;
  switch (m)
    {
#define _(a) case VLIB_PARSE_##a: t = #a; break;
      foreach_parse_match_type
#undef _
    default:
      t = 0;
      break;
    }

  if (t)
    return format (s, "%s", t);
  else
    return format (s, "unknown 0x%x", m);
}

static u8 *
format_vlib_parse_item (u8 * s, va_list * args)
{
  vlib_parse_main_t *pm = va_arg (*args, vlib_parse_main_t *);
  vlib_parse_item_t *item = va_arg (*args, vlib_parse_item_t *);
  vlib_parse_type_t *type = pool_elt_at_index (pm->parse_types, item->type);

  if (item->type == word_type_index)
    s = format (s, "%s", item->value.as_pointer);
  else
    s = format (s, "<%s>", type->name);
  return s;
}

static u8 *
format_vlib_parse_graph (u8 * s, va_list * args)
{
  vlib_parse_main_t *pm = va_arg (*args, vlib_parse_main_t *);
  vlib_parse_graph_t *node = va_arg (*args, vlib_parse_graph_t *);
  vlib_parse_item_t *item;
  vlib_parse_type_t *type;

  /* $$$ hash table */
  /* *INDENT-OFF* */
  pool_foreach (type, pm->parse_types,
                ({
                  if (type->rule_index == node - pm->parse_graph)
                    s = format (s, "\n<%s>\n", type->name);
                }));
/* *INDENT-ON* */

  if (pm->root_index == (node - pm->parse_graph))
    s = format (s, "\n<root>\n");

  item = pool_elt_at_index (pm->parse_items, node->item);

  s = format (s, "[%d] %U ", node - pm->parse_graph,
	      format_vlib_parse_item, pm, item);

  if (node->peer == (u32) ~ 0)
    s = format (s, "peer nil  ");
  else
    s = format (s, "peer %4u ", node->peer);

  if (node->deeper == (u32) ~ 0)
    s = format (s, "deeper nil  ");
  else
    s = format (s, "deeper %4u ", node->deeper);

  return s;
}

void
dump_parse_graph (void)
{
  vlib_parse_main_t *pm = &vlib_parse_main;
  vlib_parse_graph_t *node;

  /* *INDENT-OFF* */
  pool_foreach (node, pm->parse_graph, ({
    fformat(stdout, "%U\n", format_vlib_parse_graph, pm, node);
  }));
/* *INDENT-ON* */
}

always_inline void
parse_cleanup_value (vlib_parse_main_t * pm, vlib_parse_value_t * pv)
{
  vlib_parse_type_t *type = pool_elt_at_index (pm->parse_types, pv->type);
  if (type->value_cleanup_function)
    type->value_cleanup_function (pv);
}

static void
parse_reset (vlib_parse_main_t * pm, u8 * input)
{
  vlib_lex_token_t *t;
  vlib_parse_value_t *pv;

  vlib_lex_reset (pm->lex_main, input);

  vec_foreach (t, pm->tokens) vlib_lex_cleanup_token (t);

  vec_foreach (pv, pm->parse_value) parse_cleanup_value (pm, pv);

  _vec_len (pm->parse_value) = 0;
  _vec_len (pm->tokens) = 0;
  pm->current_token_index = 0;
}

static void
parse_help (vlib_parse_main_t * pm, u32 index)
{
  vlib_parse_graph_t *node;
  vlib_parse_item_t *item;
  vlib_parse_type_t *type;
  vlib_main_t *vm = pm->vlib_main;
  u8 *help_input;
  int i;

  help_input = vec_dup (pm->lex_main->input_vector);

  for (i = vec_len (help_input) - 1; i >= 0; i--)
    if (help_input[i] == '?')
      {
	help_input[i] = 0;
	_vec_len (help_input) = i;
	break;
      }

  for (i = vec_len (help_input) - 1; i >= 0; i--)
    {
      if (help_input[i] != ' ' && help_input[i] != '\t')
	break;
      help_input[i] = 0;
      break;
    }
  _vec_len (help_input) = i + 1;

  while (index != (u32) ~ 0)
    {
      node = pool_elt_at_index (pm->parse_graph, index);
      item = pool_elt_at_index (pm->parse_items, node->item);
      type = pool_elt_at_index (pm->parse_types, item->type);

      if (item->type == eof_type_index && vec_len (pm->match_items) == 0)
	/* do nothing */ ;
      else if (item->type == word_type_index)
	vlib_cli_output (vm, "%s %s\n", help_input, item->value.as_pointer);
      else
	vlib_cli_output (vm, "%s <%s>\n", help_input, type->name);
      index = node->peer;
    }
  vec_free (help_input);
}

static vlib_parse_match_t
parse_eval_internal (vlib_parse_main_t * pm, u32 index)
{
  vlib_parse_graph_t *node;
  vlib_parse_item_t *item;
  vlib_parse_type_t *type;
  vlib_parse_value_t value, *pv;
  vlib_parse_match_t rv;
  u32 *partial_matches = 0;
  vlib_lex_token_t *t;
  u32 save_token_index = (u32) ~ 0, save_match_items = 0;
  int had_value = 0;

  if (pm->current_token_index >= vec_len (pm->tokens))
    return VLIB_PARSE_MATCH_FAIL;

  /* current token */
  t = vec_elt_at_index (pm->tokens, pm->current_token_index);

  /* Help ? */
  if (PREDICT_FALSE (t->token == VLIB_LEX_qmark))
    {
      parse_help (pm, index);
      _vec_len (pm->match_items) = 0;
      return VLIB_PARSE_MATCH_DONE;
    }

  /* Across all peers at this level of the parse graph */
  while (index != (u32) ~ 0)
    {
      node = pool_elt_at_index (pm->parse_graph, index);
      item = pool_elt_at_index (pm->parse_items, node->item);
      type = pool_elt_at_index (pm->parse_types, item->type);

      /*
       * Save the token index. We may have to back up several
       * trie plies. Type-specific match functions can consume
       * multiple tokens, and they may not be optimally careful
       */
      save_token_index = pm->current_token_index;
      save_match_items = vec_len (pm->match_items);
      vec_add1 (pm->match_items, node->item);

      if (PARSE_DEBUG > 1)
	clib_warning ("Try to match token %U against node %d",
		      format_vlib_lex_token, pm->lex_main, t, index);

      /* Call the type-specific match function */
      rv = type->match_function (pm, type, t, &value);

      if (PARSE_DEBUG > 1)
	clib_warning ("returned %U", format_vlib_parse_match, rv);

      switch (rv)
	{
	case VLIB_PARSE_MATCH_VALUE:
	  /*
	   * Matched, and returned a value to append to the
	   * set of args passed to the action function
	   */
	  value.type = item->type;
	  vec_add1 (pm->parse_value, value);
	  had_value = 1;
	  /* fallthrough */

	case VLIB_PARSE_MATCH_FULL:
	unambiguous_partial_match:
	  /* Consume the matched token */
	  pm->current_token_index++;

	  /* continue matching along this path */
	  rv = parse_eval_internal (pm, node->deeper);

	  /* this is not the right path */
	  if (rv == VLIB_PARSE_MATCH_FAIL)
	    {
	      if (had_value)
		{
		  /* Delete the value */
		  value = pm->parse_value[vec_len (pm->parse_value) - 1];
		  parse_cleanup_value (pm, &value);
		  _vec_len (pm->parse_value) -= 1;
		}
	      /* Continue with the next sibling */
	      pm->current_token_index = save_token_index;
	      _vec_len (pm->match_items) = save_match_items;
	      index = node->peer;
	      break;
	    }
	  return rv;

	case VLIB_PARSE_MATCH_PARTIAL:
	  /* Partial (substring) match, remember it but keep going */
	  vec_add1 (partial_matches, node - pm->parse_graph);
	  index = node->peer;
	  break;

	case VLIB_PARSE_MATCH_FAIL:
	  /* Continue with the next sibling */
	  index = node->peer;
	  _vec_len (pm->match_items) = save_match_items;
	  break;

	case VLIB_PARSE_MATCH_DONE:
	  /* Parse complete, invoke the action function */
	  if (PARSE_DEBUG > 0)
	    clib_warning ("parse_value: %U", format_vlib_parse_value, pm);

	  {
	    vlib_parse_eval_function_t *f = item->value.as_pointer;
	    if (f)
	      rv = f (pm, item, pm->parse_value);
	  }

	  vec_foreach (pv, pm->parse_value) parse_cleanup_value (pm, pv);
	  _vec_len (pm->parse_value) = 0;
	  _vec_len (pm->match_items) = 0;
	  return rv;

	case VLIB_PARSE_MATCH_AMBIGUOUS:
	case VLIB_PARSE_MATCH_EVAL_FAIL:
	case VLIB_PARSE_MATCH_RULE:
	  _vec_len (pm->match_items) = save_match_items;
	  return rv;
	}
    }

  /*
   * Out of siblings. If we have exactly one partial match
   * we win
   */
  if (vec_len (partial_matches) == 1)
    {
      index = partial_matches[0];
      node = pool_elt_at_index (pm->parse_graph, index);
      vec_free (partial_matches);
      goto unambiguous_partial_match;
    }

  /* Ordinary loser */
  rv = VLIB_PARSE_MATCH_FAIL;

  /* Ambiguous loser */
  if (vec_len (partial_matches) > 1)
    {
      vec_free (partial_matches);
      rv = VLIB_PARSE_MATCH_AMBIGUOUS;
    }

  _vec_len (pm->match_items) = save_match_items;
  return rv;
}

vlib_parse_match_t
rule_match (vlib_parse_main_t * pm, vlib_parse_type_t * type,
	    vlib_lex_token_t * t, vlib_parse_value_t * valuep)
{
  vlib_parse_match_t rv;
  static int recursion_level;

  if (PARSE_DEBUG > 1)
    clib_warning ("[%d]: try to match type %s graph index %d",
		  recursion_level, type->name, type->rule_index);
  recursion_level++;
  rv = parse_eval_internal (pm, type->rule_index);
  recursion_level--;

  /* Break the recusive unwind here... */
  if (rv == VLIB_PARSE_MATCH_RULE)
    {
      if (PARSE_DEBUG > 1)
	clib_warning ("[%d]: type %s matched", recursion_level, type->name);

      return VLIB_PARSE_MATCH_FULL;
    }
  else
    {
      if (PARSE_DEBUG > 1)
	clib_warning ("[%d]: type %s returns %U", recursion_level, type->name,
		      format_vlib_parse_match, rv);
    }
  return rv;
}

static int
parse_eval (vlib_parse_main_t * pm, u8 * input)
{
  vlib_lex_token_t *t;

  parse_reset (pm, input);

  /* Tokenize the entire input vector */
  do
    {
      vec_add2 (pm->tokens, t, 1);
      vlib_lex_get_token (pm->lex_main, t);
    }
  while (t->token != VLIB_LEX_eof);

  /* Feed it to the parser */
  return parse_eval_internal (pm, pm->root_index);
}

/* Temporary vlib stub */
vlib_parse_match_t
vlib_parse_eval (u8 * input)
{
  return parse_eval (&vlib_parse_main, input);
}

u16
parse_type_find_or_create (vlib_parse_main_t * pm, vlib_parse_type_t * t)
{
  uword *p;
  vlib_parse_type_t *n;
  u8 *name_copy;

  p = hash_get_mem (pm->parse_type_by_name_hash, t->name);
  if (p)
    return p[0];

  pool_get (pm->parse_types, n);
  *n = *t;
  n->rule_index = (u32) ~ 0;

  name_copy = format (0, "%s%c", n->name, 0);

  hash_set_mem (pm->parse_type_by_name_hash, name_copy, n - pm->parse_types);
  return n - pm->parse_types;
}

u16
parse_type_find_by_name (vlib_parse_main_t * pm, char *name)
{
  uword *p;

  p = hash_get_mem (pm->parse_type_by_name_hash, name);
  if (p)
    return p[0];

  return (u16) ~ 0;
}

u32
parse_item_find_or_create (vlib_parse_main_t * pm, vlib_parse_item_t * item)
{
  uword *p;
  vlib_parse_item_t *i;

  /* Exact match the entire item */
  p = mhash_get (&pm->parse_item_hash, item);
  if (p)
    return p[0];

  pool_get (pm->parse_items, i);
  *i = *item;

  mhash_set (&pm->parse_item_hash, i, i - pm->parse_items, 0);
  return i - pm->parse_items;
}

static void
parse_type_and_graph_init (vlib_parse_main_t * pm)
{
  u32 eof_index;
  vlib_parse_type_t type;
  vlib_parse_item_t item;

  memset (&type, 0, sizeof (type));

#define foreach_token_type                      \
  _ (eof)                                       \
  _ (rule_eof)                                  \
  _ (word)                                      \
  _ (number)                                    \
  _ (plus)                                      \
  _ (minus)                                     \
  _ (star)                                      \
  _ (slash)                                     \
  _ (lpar)                                      \
  _ (rpar)

#define _(a) a##_type_index = parse_type_find_by_name (pm, #a);
  foreach_token_type
#undef _
    memset (&item, 0, sizeof (item));
  item.type = eof_type_index;

  eof_index = parse_item_find_or_create (pm, &item);
  pm->root_index = (u32) ~ 0;

#if 0
  pool_get (pm->parse_graph, g);
  memset (g, 0xff, sizeof (*g));
  g->item = eof_index;
  pm->root_index = 0;
#endif
}



static void
tokenize (vlib_parse_main_t * pm, parse_registration_t * pr)
{
  vlib_lex_token_t *t;
  pm->register_input = format (pm->register_input,
			       "%s%c", pr->initializer, 0);

  parse_reset (pm, pm->register_input);

  do
    {
      vec_add2 (pm->tokens, t, 1);
      vlib_lex_get_token (pm->lex_main, t);
    }
  while (t->token != VLIB_LEX_eof);
  _vec_len (pm->register_input) = 0;
}

static int
is_typed_rule (vlib_parse_main_t * pm)
{
  vlib_lex_token_t *t = vec_elt_at_index (pm->tokens, 0);

  /* <mytype> = blah blah blah */
  if (vec_len (pm->tokens) >= 4
      && t[0].token == VLIB_LEX_lt
      && t[1].token == VLIB_LEX_word
      && t[2].token == VLIB_LEX_gt && t[3].token == VLIB_LEX_equals)
    return 1;
  return 0;
}

static int
token_matches_graph_node (vlib_parse_main_t * pm,
			  vlib_lex_token_t * t,
			  vlib_parse_graph_t * node,
			  vlib_parse_item_t * item,
			  vlib_parse_type_t * type, u32 * token_increment)
{
  /* EOFs don't match */
  if (t->token == VLIB_LEX_eof)
    return 0;

  /* New chain element is a word */
  if (t->token == VLIB_LEX_word)
    {
      /* but the item in hand is not a word */
      if (item->type != word_type_index)
	return 0;

      /* Or it's not this particular word */
      if (strcmp (t->value.as_pointer, item->value.as_pointer))
	return 0;
      *token_increment = 1;
      return 1;
    }
  /* New chain element is a type-name: < TYPE-NAME > */
  if (t->token == VLIB_LEX_lt)
    {
      u16 token_type_index;

      /* < TYPE > */
      if (t[1].token != VLIB_LEX_word || t[2].token != VLIB_LEX_gt)
	{
	  clib_warning (0, "broken type name in '%s'", pm->register_input);
	  return 0;
	}

      token_type_index = parse_type_find_by_name (pm, t[1].value.as_pointer);
      if (token_type_index == (u16) ~ 0)
	{
	  clib_warning (0, "unknown type '%s'", t[1].value.as_pointer);
	  return 0;
	}

      /* Its a known type but does not match. */
      if (item->type != token_type_index)
	return 0;

      *token_increment = 3;
      return 1;
    }
  clib_warning ("BUG: t->token = %d", t->token);
  return 0;
}

u32
generate_subgraph_from_tokens (vlib_parse_main_t * pm,
			       vlib_lex_token_t * t,
			       u32 * new_subgraph_depth,
			       parse_registration_t * pr, int not_a_rule)
{
  vlib_parse_graph_t *g, *last_g;
  vlib_parse_item_t new_item;
  u32 rv = (u32) ~ 0, new_item_index, last_index = (u32) ~ 0;
  u16 token_type_index;
  u32 depth = 0;

  while (t < pm->tokens + vec_len (pm->tokens))
    {
      memset (&new_item, 0, sizeof (new_item));

      if (t->token == VLIB_LEX_word)
	{
	  new_item.type = word_type_index;
	  new_item.value.as_pointer = vec_dup ((u8 *) t->value.as_pointer);
	  new_item_index = parse_item_find_or_create (pm, &new_item);
	  t++;
	}
      else if (t->token == VLIB_LEX_lt)
	{
	  if (t[1].token != VLIB_LEX_word || t[2].token != VLIB_LEX_gt)
	    {
	      clib_warning ("broken type name in '%s'", pm->register_input);
	      goto screwed;
	    }
	  token_type_index = parse_type_find_by_name (pm,
						      t[1].value.as_pointer);
	  if (token_type_index == (u16) ~ 0)
	    {
	      clib_warning ("unknown type 2 '%s'", t[1].value.as_pointer);
	      goto screwed;
	    }

	  new_item.type = token_type_index;
	  new_item.value.as_pointer = 0;
	  new_item_index = parse_item_find_or_create (pm, &new_item);
	  t += 3;		/* skip < <type-name> and > */
	}
      else if (t->token == VLIB_LEX_eof)
	{
	screwed:
	  new_item.type = not_a_rule ? eof_type_index : rule_eof_type_index;
	  new_item.value.as_pointer = pr->eof_match;
	  new_item_index = parse_item_find_or_create (pm, &new_item);
	  t++;
	}
      else
	{
	  clib_warning ("unexpected token %U index %d in '%s'",
			format_vlib_lex_token, pm->lex_main, t,
			t - pm->tokens, pm->register_input);
	  goto screwed;
	}

      pool_get (pm->parse_graph, g);
      memset (g, 0xff, sizeof (*g));
      g->item = new_item_index;
      depth++;

      if (rv == (u32) ~ 0)
	{
	  rv = g - pm->parse_graph;
	  last_index = rv;
	}
      else
	{
	  last_g = pool_elt_at_index (pm->parse_graph, last_index);
	  last_index = last_g->deeper = g - pm->parse_graph;
	}
    }
  *new_subgraph_depth = depth;
  return rv;
}

static u32
measure_depth (vlib_parse_main_t * pm, u32 index)
{
  vlib_parse_graph_t *node;
  vlib_parse_item_t *item;
  u32 max = 0;
  u32 depth;

  if (index == (u32) ~ 0)
    return 0;

  node = pool_elt_at_index (pm->parse_graph, index);
  item = pool_elt_at_index (pm->parse_items, node->item);

  if (item->type == eof_type_index)
    return 1;

  while (index != (u32) ~ 0)
    {
      node = pool_elt_at_index (pm->parse_graph, index);
      depth = measure_depth (pm, node->deeper);
      if (max < depth)
	max = depth;
      index = node->peer;
    }

  return max + 1;
}

static void
add_subgraph_to_graph (vlib_parse_main_t * pm,
		       u32 last_matching_index,
		       u32 graph_root_index,
		       u32 new_subgraph_index, u32 new_subgraph_depth)
{
  vlib_parse_graph_t *parent_node;
  int new_subgraph_longest = 1;
  u32 current_peer_index;
  u32 current_depth;
  vlib_parse_graph_t *current_peer = 0;
  vlib_parse_graph_t *new_subgraph_node =
    pool_elt_at_index (pm->parse_graph, new_subgraph_index);

  /*
   * Case 1: top-level peer. Splice into the top-level
   * peer chain according to rule depth
   */
  if (last_matching_index == (u32) ~ 0)
    {
      u32 index = graph_root_index;
      while (1)
	{
	  current_peer = pool_elt_at_index (pm->parse_graph, index);
	  current_depth = measure_depth (pm, index);
	  if (current_depth < new_subgraph_depth
	      || current_peer->peer == (u32) ~ 0)
	    break;
	  index = current_peer->peer;
	}
      new_subgraph_node->peer = current_peer->peer;
      current_peer->peer = new_subgraph_index;
      return;
    }

  parent_node = pool_elt_at_index (pm->parse_graph, last_matching_index);
  current_peer_index = parent_node->deeper;

  while (current_peer_index != (u32) ~ 0)
    {
      current_peer = pool_elt_at_index (pm->parse_graph, current_peer_index);
      current_depth = measure_depth (pm, current_peer_index);
      if (current_depth < new_subgraph_depth)
	break;
      new_subgraph_longest = 0;
      current_peer_index = current_peer->peer;
    }

  ASSERT (current_peer);

  if (new_subgraph_longest)
    {
      new_subgraph_node->peer = parent_node->deeper;
      parent_node->deeper = new_subgraph_index;
    }
  else
    {
      new_subgraph_node->peer = current_peer->peer;
      current_peer->peer = new_subgraph_index;
    }
}

static clib_error_t *
parse_register_one (vlib_parse_main_t * pm, parse_registration_t * pr)
{
  u32 graph_root_index;
  u16 subgraph_type_index = (u16) ~ 0;
  vlib_parse_type_t *subgraph_type = 0;
  vlib_lex_token_t *t;
  vlib_parse_graph_t *node;
  u32 node_index, last_index, token_increment, new_subgraph_index;
  u32 new_subgraph_depth, last_matching_index;
  vlib_parse_item_t *item;
  vlib_parse_type_t *type;

  int use_main_graph = 1;

  tokenize (pm, pr);

  /* A typed rule? */
  if (is_typed_rule (pm))
    {
      /* Get the type and its current subgraph root, if any */
      t = vec_elt_at_index (pm->tokens, 1);
      subgraph_type_index = parse_type_find_by_name (pm, t->value.as_pointer);
      if (subgraph_type_index == (u16) ~ 0)
	return clib_error_return (0, "undeclared type '%s'",
				  t->value.as_pointer);
      subgraph_type =
	pool_elt_at_index (pm->parse_types, subgraph_type_index);
      graph_root_index = subgraph_type->rule_index;
      /* Skip "mytype> = */
      t += 3;
      use_main_graph = 0;
    }
  else
    {
      /* top-level graph */
      graph_root_index = pm->root_index;
      t = vec_elt_at_index (pm->tokens, 0);
    }

  last_matching_index = (u32) ~ 0;
  last_index = node_index = graph_root_index;

  /* Find the first token which isn't already being parsed */
  while (t < pm->tokens + vec_len (pm->tokens) && node_index != (u32) ~ 0)
    {
      node = pool_elt_at_index (pm->parse_graph, node_index);
      item = pool_elt_at_index (pm->parse_items, node->item);
      type = pool_elt_at_index (pm->parse_types, item->type);
      last_index = node_index;

      if (token_matches_graph_node
	  (pm, t, node, item, type, &token_increment))
	{
	  t += token_increment;
	  last_matching_index = node_index;
	  node_index = node->deeper;
	}
      else
	node_index = node->peer;
    }

  new_subgraph_index =
    generate_subgraph_from_tokens (pm, t, &new_subgraph_depth, pr,
				   use_main_graph);

  /* trivial cases: first graph node or first type rule */
  if (graph_root_index == (u32) ~ 0)
    {
      if (use_main_graph)
	pm->root_index = new_subgraph_index;
      else
	subgraph_type->rule_index = new_subgraph_index;
      return 0;
    }

  add_subgraph_to_graph (pm, last_matching_index, graph_root_index,
			 new_subgraph_index, new_subgraph_depth);
  return 0;
}

static clib_error_t *
parse_register (vlib_main_t * vm,
		parse_registration_t * lo,
		parse_registration_t * hi, vlib_parse_main_t * pm)
{
  parse_registration_t *pr;

  for (pr = lo; pr < hi; pr = vlib_elf_section_data_next (pr, 0))
    vec_add1 (pm->parse_registrations, pr);

  return 0;
}

static clib_error_t *
parse_register_one_type (vlib_parse_main_t * pm, vlib_parse_type_t * rp)
{
  (void) parse_type_find_or_create (pm, (vlib_parse_type_t *) rp);
  return 0;
}

static clib_error_t *
parse_type_register (vlib_main_t * vm,
		     vlib_parse_type_t * lo,
		     vlib_parse_type_t * hi, vlib_parse_main_t * pm)
{
  clib_error_t *error = 0;
  vlib_parse_type_t *ptr;

  for (ptr = lo; ptr < hi; ptr = vlib_elf_section_data_next (ptr, 0))
    {
      error = parse_register_one_type (pm, ptr);
      if (error)
	goto done;
    }

done:
  return error;
}

clib_error_t *vlib_stdlex_init (vlib_main_t * vm) __attribute__ ((weak));
clib_error_t *
vlib_stdlex_init (vlib_main_t * vm)
{
  (void) vlib_lex_add_table ("ignore_everything");
  return 0;
}

static int
compute_rule_length (parse_registration_t * r)
{
  int length, i;
  vlib_parse_main_t *pm = &vlib_parse_main;

  if (r->rule_length)
    return r->rule_length;

  length = 0;

  tokenize (pm, r);
  length = vec_len (pm->tokens);

  /* Account for "<foo> = " in "<foo> = bar" etc. */
  if (is_typed_rule (pm))
    length -= 2;

  for (i = 0; i < vec_len (pm->tokens); i++)
    {
      switch (pm->tokens[i].token)
	{
	case VLIB_LEX_lt:
	case VLIB_LEX_gt:
	  length -= 1;

	default:
	  break;
	}
    }

  ASSERT (length > 0);
  r->rule_length = length;
  return length;
}

static int
rule_length_compare (parse_registration_t * r1, parse_registration_t * r2)
{
  compute_rule_length (r1);
  compute_rule_length (r2);
  /* Descending sort */
  return r2->rule_length - r1->rule_length;
}


static clib_error_t *
parse_init (vlib_main_t * vm)
{
  vlib_parse_main_t *pm = &vlib_parse_main;
  vlib_lex_main_t *lm = &vlib_lex_main;
  vlib_elf_section_bounds_t *b, *bounds;
  clib_error_t *error = 0;
  parse_registration_t *rule;
  int i;

  if ((error = vlib_call_init_function (vm, lex_onetime_init)))
    return error;

  if ((error = vlib_stdlex_init (vm)))
    return error;

  if ((error = vlib_call_init_function (vm, parse_builtin_init)))
    return error;

  pm->vlib_main = vm;
  pm->lex_main = lm;

  mhash_init (&pm->parse_item_hash, sizeof (u32), sizeof (vlib_parse_item_t));
  pm->parse_type_by_name_hash = hash_create_string (0, sizeof (u32));

  vec_validate (pm->parse_value, 16);
  vec_validate (pm->tokens, 16);
  vec_validate (pm->register_input, 32);
  vec_validate (pm->match_items, 16);

  _vec_len (pm->parse_value) = 0;
  _vec_len (pm->tokens) = 0;
  _vec_len (pm->register_input) = 0;
  _vec_len (pm->match_items) = 0;

  bounds = vlib_get_elf_section_bounds (vm, "parse_type_registrations");
  vec_foreach (b, bounds)
  {
    error = parse_type_register (vm, b->lo, b->hi, pm);
    if (error)
      break;
  }
  vec_free (bounds);

  parse_type_and_graph_init (pm);

  bounds = vlib_get_elf_section_bounds (vm, "parse_registrations");
  vec_foreach (b, bounds)
  {
    error = parse_register (vm, b->lo, b->hi, pm);
    if (error)
      break;
  }
  vec_free (bounds);

  vec_sort_with_function (pm->parse_registrations, rule_length_compare);

  for (i = 0; i < vec_len (pm->parse_registrations); i++)
    {
      rule = pm->parse_registrations[i];
      parse_register_one (pm, rule);
    }

  return error;
}

VLIB_INIT_FUNCTION (parse_init);

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */