nest/rt-attr.c

   1 /*
   2  *      BIRD -- Route Attribute Cache
   3  *
   4  *      (c) 1998--2000 Martin Mares <mj@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 /**
  10  * DOC: Route attribute cache
  11  *
  12  * Each route entry carries a set of route attributes. Several of them
  13  * vary from route to route, but most attributes are usually common
  14  * for a large number of routes. To conserve memory, we've decided to
  15  * store only the varying ones directly in the &rte and hold the rest
  16  * in a special structure called &rta which is shared among all the
  17  * &rte's with these attributes.
  18  *
  19  * Each &rta contains all the static attributes of the route (i.e.,
  20  * those which are always present) as structure members and a list of
  21  * dynamic attributes represented by a linked list of &ea_list
  22  * structures, each of them consisting of an array of &eattr's containing
  23  * the individual attributes. An attribute can be specified more than once
  24  * in the &ea_list chain and in such case the first occurrence overrides
  25  * the others. This semantics is used especially when someone (for example
  26  * a filter) wishes to alter values of several dynamic attributes, but
  27  * it wants to preserve the original attribute lists maintained by
  28  * another module.
  29  *
  30  * Each &eattr contains an attribute identifier (split to protocol ID and
  31  * per-protocol attribute ID), protocol dependent flags, a type code (consisting
  32  * of several bit fields describing attribute characteristics) and either an
  33  * embedded 32-bit value or a pointer to a &adata structure holding attribute
  34  * contents.
  35  *
  36  * There exist two variants of &rta's -- cached and un-cached ones. Un-cached
  37  * &rta's can have arbitrarily complex structure of &ea_list's and they
  38  * can be modified by any module in the route processing chain. Cached
  39  * &rta's have their attribute lists normalized (that means at most one
  40  * &ea_list is present and its values are sorted in order to speed up
  41  * searching), they are stored in a hash table to make fast lookup possible
  42  * and they are provided with a use count to allow sharing.
  43  *
  44  * Routing tables always contain only cached &rta's.
  45  */
  46
  47 #include "nest/bird.h"
  48 #include "nest/route.h"
  49 #include "nest/protocol.h"
  50 #include "nest/iface.h"
  51 #include "nest/cli.h"
  52 #include "nest/attrs.h"
  53 #include "lib/alloca.h"
  54 #include "lib/resource.h"
  55 #include "lib/string.h"
  56
  57 pool *rta_pool;
  58
  59 static slab *rta_slab;
  60 static slab *mpnh_slab;
  61
  62 struct protocol *attr_class_to_protocol[EAP_MAX];
  63
  64 static inline unsigned int
  65 mpnh_hash(struct mpnh *x)
  66 {
  67   unsigned int h = 0;
  68   for (; x; x = x->next)
  69     h ^= ipa_hash(x->gw);
  70
  71   return h;
  72 }
  73
  74 int
  75 mpnh__same(struct mpnh *x, struct mpnh *y)
  76 {
  77   for (; x && y; x = x->next, y = y->next)
  78     if (!ipa_equal(x->gw, y->gw) || (x->iface != y->iface) || (x->weight != y->weight))
  79       return 0;
  80
  81   return x == y;
  82 }
  83
  84 static struct mpnh *
  85 mpnh_copy(struct mpnh *o)
  86 {
  87   struct mpnh *first = NULL;
  88   struct mpnh **last = &first;
  89
  90   for (; o; o = o->next)
  91     {
  92       struct mpnh *n = sl_alloc(mpnh_slab);
  93       n->gw = o->gw;
  94       n->iface = o->iface;
  95       n->next = NULL;
  96       n->weight = o->weight;
  97
  98       *last = n;
  99       last = &(n->next);
 100     }
 101
 102   return first;
 103 }
 104
 105 static void
 106 mpnh_free(struct mpnh *o)
 107 {
 108   struct mpnh *n;
 109
 110   while (o)
 111     {
 112       n = o->next;
 113       sl_free(mpnh_slab, o);
 114       o = n;
 115     }
 116 }
 117
 118
 119 /*
 120  *      Extended Attributes
 121  */
 122
 123 static inline eattr *
 124 ea__find(ea_list *e, unsigned id)
 125 {
 126   eattr *a;
 127   int l, r, m;
 128
 129   while (e)
 130     {
 131       if (e->flags & EALF_BISECT)
 132         {
 133           l = 0;
 134           r = e->count - 1;
 135           while (l <= r)
 136             {
 137               m = (l+r) / 2;
 138               a = &e->attrs[m];
 139               if (a->id == id)
 140                 return a;
 141               else if (a->id < id)
 142                 l = m+1;
 143               else
 144                 r = m-1;
 145             }
 146         }
 147       else
 148         for(m=0; m<e->count; m++)
 149           if (e->attrs[m].id == id)
 150             return &e->attrs[m];
 151       e = e->next;
 152     }
 153   return NULL;
 154 }
 155
 156 /**
 157  * ea_find - find an extended attribute
 158  * @e: attribute list to search in
 159  * @id: attribute ID to search for
 160  *
 161  * Given an extended attribute list, ea_find() searches for a first
 162  * occurrence of an attribute with specified ID, returning either a pointer
 163  * to its &eattr structure or %NULL if no such attribute exists.
 164  */
 165 eattr *
 166 ea_find(ea_list *e, unsigned id)
 167 {
 168   eattr *a = ea__find(e, id & EA_CODE_MASK);
 169
 170   if (a && (a->type & EAF_TYPE_MASK) == EAF_TYPE_UNDEF &&
 171       !(id & EA_ALLOW_UNDEF))
 172     return NULL;
 173   return a;
 174 }
 175
 176 /**
 177  * ea_get_int - fetch an integer attribute
 178  * @e: attribute list
 179  * @id: attribute ID
 180  * @def: default value
 181  *
 182  * This function is a shortcut for retrieving a value of an integer attribute
 183  * by calling ea_find() to find the attribute, extracting its value or returning
 184  * a provided default if no such attribute is present.
 185  */
 186 int
 187 ea_get_int(ea_list *e, unsigned id, int def)
 188 {
 189   eattr *a = ea_find(e, id);
 190   if (!a)
 191     return def;
 192   return a->u.data;
 193 }
 194
 195 static inline void
 196 ea_do_sort(ea_list *e)
 197 {
 198   unsigned n = e->count;
 199   eattr *a = e->attrs;
 200   eattr *b = alloca(n * sizeof(eattr));
 201   unsigned s, ss;
 202
 203   /* We need to use a stable sorting algorithm, hence mergesort */
 204   do
 205     {
 206       s = ss = 0;
 207       while (s < n)
 208         {
 209           eattr *p, *q, *lo, *hi;
 210           p = b;
 211           ss = s;
 212           *p++ = a[s++];
 213           while (s < n && p[-1].id <= a[s].id)
 214             *p++ = a[s++];
 215           if (s < n)
 216             {
 217               q = p;
 218               *p++ = a[s++];
 219               while (s < n && p[-1].id <= a[s].id)
 220                 *p++ = a[s++];
 221               lo = b;
 222               hi = q;
 223               s = ss;
 224               while (lo < q && hi < p)
 225                 if (lo->id <= hi->id)
 226                   a[s++] = *lo++;
 227                 else
 228                   a[s++] = *hi++;
 229               while (lo < q)
 230                 a[s++] = *lo++;
 231               while (hi < p)
 232                 a[s++] = *hi++;
 233             }
 234         }
 235     }
 236   while (ss);
 237 }
 238
 239 static inline void
 240 ea_do_prune(ea_list *e)
 241 {
 242   eattr *s, *d, *l, *s0;
 243   int i = 0;
 244
 245   /* Discard duplicates and undefs. Do you remember sorting was stable? */
 246   s = d = e->attrs;
 247   l = e->attrs + e->count;
 248   while (s < l)
 249     {
 250       s0 = s++;
 251       while (s < l && s->id == s[-1].id)
 252         s++;
 253       /* s0 is the most recent version, s[-1] the oldest one */
 254       if ((s0->type & EAF_TYPE_MASK) != EAF_TYPE_UNDEF)
 255         {
 256           *d = *s0;
 257           d->type = (d->type & ~EAF_ORIGINATED) | (s[-1].type & EAF_ORIGINATED);
 258           d++;
 259           i++;
 260         }
 261     }
 262   e->count = i;
 263 }
 264
 265 /**
 266  * ea_sort - sort an attribute list
 267  * @e: list to be sorted
 268  *
 269  * This function takes a &ea_list chain and sorts the attributes
 270  * within each of its entries.
 271  *
 272  * If an attribute occurs multiple times in a single &ea_list,
 273  * ea_sort() leaves only the first (the only significant) occurrence.
 274  */
 275 void
 276 ea_sort(ea_list *e)
 277 {
 278   while (e)
 279     {
 280       if (!(e->flags & EALF_SORTED))
 281         {
 282           ea_do_sort(e);
 283           ea_do_prune(e);
 284           e->flags |= EALF_SORTED;
 285         }
 286       if (e->count > 5)
 287         e->flags |= EALF_BISECT;
 288       e = e->next;
 289     }
 290 }
 291
 292 /**
 293  * ea_scan - estimate attribute list size
 294  * @e: attribute list
 295  *
 296  * This function calculates an upper bound of the size of
 297  * a given &ea_list after merging with ea_merge().
 298  */
 299 unsigned
 300 ea_scan(ea_list *e)
 301 {
 302   unsigned cnt = 0;
 303
 304   while (e)
 305     {
 306       cnt += e->count;
 307       e = e->next;
 308     }
 309   return sizeof(ea_list) + sizeof(eattr)*cnt;
 310 }
 311
 312 /**
 313  * ea_merge - merge segments of an attribute list
 314  * @e: attribute list
 315  * @t: buffer to store the result to
 316  *
 317  * This function takes a possibly multi-segment attribute list
 318  * and merges all of its segments to one.
 319  *
 320  * The primary use of this function is for &ea_list normalization:
 321  * first call ea_scan() to determine how much memory will the result
 322  * take, then allocate a buffer (usually using alloca()), merge the
 323  * segments with ea_merge() and finally sort and prune the result
 324  * by calling ea_sort().
 325  */
 326 void
 327 ea_merge(ea_list *e, ea_list *t)
 328 {
 329   eattr *d = t->attrs;
 330
 331   t->flags = 0;
 332   t->count = 0;
 333   t->next = NULL;
 334   while (e)
 335     {
 336       memcpy(d, e->attrs, sizeof(eattr)*e->count);
 337       t->count += e->count;
 338       d += e->count;
 339       e = e->next;
 340     }
 341 }
 342
 343 /**
 344  * ea_same - compare two &ea_list's
 345  * @x: attribute list
 346  * @y: attribute list
 347  *
 348  * ea_same() compares two normalized attribute lists @x and @y and returns
 349  * 1 if they contain the same attributes, 0 otherwise.
 350  */
 351 int
 352 ea_same(ea_list *x, ea_list *y)
 353 {
 354   int c;
 355
 356   if (!x || !y)
 357     return x == y;
 358   ASSERT(!x->next && !y->next);
 359   if (x->count != y->count)
 360     return 0;
 361   for(c=0; c<x->count; c++)
 362     {
 363       eattr *a = &x->attrs[c];
 364       eattr *b = &y->attrs[c];
 365
 366       if (a->id != b->id ||
 367           a->flags != b->flags ||
 368           a->type != b->type ||
 369           ((a->type & EAF_EMBEDDED) ? a->u.data != b->u.data :
 370            (a->u.ptr->length != b->u.ptr->length || memcmp(a->u.ptr->data, b->u.ptr->data, a->u.ptr->length))))
 371         return 0;
 372     }
 373   return 1;
 374 }
 375
 376 static inline ea_list *
 377 ea_list_copy(ea_list *o)
 378 {
 379   ea_list *n;
 380   unsigned i, len;
 381
 382   if (!o)
 383     return NULL;
 384   ASSERT(!o->next);
 385   len = sizeof(ea_list) + sizeof(eattr) * o->count;
 386   n = mb_alloc(rta_pool, len);
 387   memcpy(n, o, len);
 388   n->flags |= EALF_CACHED;
 389   for(i=0; i<o->count; i++)
 390     {
 391       eattr *a = &n->attrs[i];
 392       if (!(a->type & EAF_EMBEDDED))
 393         {
 394           unsigned size = sizeof(struct adata) + a->u.ptr->length;
 395           struct adata *d = mb_alloc(rta_pool, size);
 396           memcpy(d, a->u.ptr, size);
 397           a->u.ptr = d;
 398         }
 399     }
 400   return n;
 401 }
 402
 403 static inline void
 404 ea_free(ea_list *o)
 405 {
 406   int i;
 407
 408   if (o)
 409     {
 410       ASSERT(!o->next);
 411       for(i=0; i<o->count; i++)
 412         {
 413           eattr *a = &o->attrs[i];
 414           if (!(a->type & EAF_EMBEDDED))
 415             mb_free(a->u.ptr);
 416         }
 417       mb_free(o);
 418     }
 419 }
 420
 421 static int
 422 get_generic_attr(eattr *a, byte **buf, int buflen UNUSED)
 423 {
 424   if (a->id == EA_GEN_IGP_METRIC)
 425     {
 426       *buf += bsprintf(*buf, "igp_metric");
 427       return GA_NAME;
 428     }
 429
 430   return GA_UNKNOWN;
 431 }
 432
 433 static inline void
 434 opaque_format(struct adata *ad, byte *buf, unsigned int size)
 435 {
 436   byte *bound = buf + size - 10;
 437   int i;
 438
 439   for(i = 0; i < ad->length; i++)
 440     {
 441       if (buf > bound)
 442         {
 443           strcpy(buf, " ...");
 444           return;
 445         }
 446       if (i)
 447         *buf++ = ' ';
 448
 449       buf += bsprintf(buf, "%02x", ad->data[i]);
 450     }
 451
 452   *buf = 0;
 453   return;
 454 }
 455
 456 static inline void
 457 ea_show_int_set(struct cli *c, struct adata *ad, int way, byte *pos, byte *buf, byte *end)
 458 {
 459   int i = int_set_format(ad, way, 0, pos, end - pos);
 460   cli_printf(c, -1012, "%s", buf);
 461   while (i)
 462     {
 463       i = int_set_format(ad, way, i, buf, end - buf - 1);
 464       cli_printf(c, -1012, "\t%s", buf);
 465     }
 466 }
 467
 468 /**
 469  * ea_show - print an &eattr to CLI
 470  * @c: destination CLI
 471  * @e: attribute to be printed
 472  *
 473  * This function takes an extended attribute represented by its &eattr
 474  * structure and prints it to the CLI according to the type information.
 475  *
 476  * If the protocol defining the attribute provides its own
 477  * get_attr() hook, it's consulted first.
 478  */
 479 void
 480 ea_show(struct cli *c, eattr *e)
 481 {
 482   struct protocol *p;
 483   int status = GA_UNKNOWN;
 484   struct adata *ad = (e->type & EAF_EMBEDDED) ? NULL : e->u.ptr;
 485   byte buf[CLI_MSG_SIZE];
 486   byte *pos = buf, *end = buf + sizeof(buf);
 487
 488   if (p = attr_class_to_protocol[EA_PROTO(e->id)])
 489     {
 490       pos += bsprintf(pos, "%s.", p->name);
 491       if (p->get_attr)
 492         status = p->get_attr(e, pos, end - pos);
 493       pos += strlen(pos);
 494     }
 495   else if (EA_PROTO(e->id))
 496     pos += bsprintf(pos, "%02x.", EA_PROTO(e->id));
 497   else
 498     status = get_generic_attr(e, &pos, end - pos);
 499
 500   if (status < GA_NAME)
 501     pos += bsprintf(pos, "%02x", EA_ID(e->id));
 502   if (status < GA_FULL)
 503     {
 504       *pos++ = ':';
 505       *pos++ = ' ';
 506       switch (e->type & EAF_TYPE_MASK)
 507         {
 508         case EAF_TYPE_INT:
 509           bsprintf(pos, "%u", e->u.data);
 510           break;
 511         case EAF_TYPE_OPAQUE:
 512           opaque_format(ad, pos, end - pos);
 513           break;
 514         case EAF_TYPE_IP_ADDRESS:
 515           bsprintf(pos, "%I", *(ip_addr *) ad->data);
 516           break;
 517         case EAF_TYPE_ROUTER_ID:
 518           bsprintf(pos, "%R", e->u.data);
 519           break;
 520         case EAF_TYPE_AS_PATH:
 521           as_path_format(ad, pos, end - pos);
 522           break;
 523         case EAF_TYPE_INT_SET:
 524           ea_show_int_set(c, ad, 1, pos, buf, end);
 525           return;
 526         case EAF_TYPE_UNDEF:
 527         default:
 528           bsprintf(pos, "<type %02x>", e->type);
 529         }
 530     }
 531   cli_printf(c, -1012, "%s", buf);
 532 }
 533
 534 /**
 535  * ea_dump - dump an extended attribute
 536  * @e: attribute to be dumped
 537  *
 538  * ea_dump() dumps contents of the extended attribute given to
 539  * the debug output.
 540  */
 541 void
 542 ea_dump(ea_list *e)
 543 {
 544   int i;
 545
 546   if (!e)
 547     {
 548       debug("NONE");
 549       return;
 550     }
 551   while (e)
 552     {
 553       debug("[%c%c%c]",
 554             (e->flags & EALF_SORTED) ? 'S' : 's',
 555             (e->flags & EALF_BISECT) ? 'B' : 'b',
 556             (e->flags & EALF_CACHED) ? 'C' : 'c');
 557       for(i=0; i<e->count; i++)
 558         {
 559           eattr *a = &e->attrs[i];
 560           debug(" %02x:%02x.%02x", EA_PROTO(a->id), EA_ID(a->id), a->flags);
 561           if (a->type & EAF_TEMP)
 562             debug("T");
 563           debug("=%c", "?iO?I?P???S?????" [a->type & EAF_TYPE_MASK]);
 564           if (a->type & EAF_ORIGINATED)
 565             debug("o");
 566           if (a->type & EAF_EMBEDDED)
 567             debug(":%08x", a->u.data);
 568           else
 569             {
 570               int j, len = a->u.ptr->length;
 571               debug("[%d]:", len);
 572               for(j=0; j<len; j++)
 573                 debug("%02x", a->u.ptr->data[j]);
 574             }
 575         }
 576       if (e = e->next)
 577         debug(" | ");
 578     }
 579 }
 580
 581 /**
 582  * ea_hash - calculate an &ea_list hash key
 583  * @e: attribute list
 584  *
 585  * ea_hash() takes an extended attribute list and calculated a hopefully
 586  * uniformly distributed hash value from its contents.
 587  */
 588 inline unsigned int
 589 ea_hash(ea_list *e)
 590 {
 591   u32 h = 0;
 592   int i;
 593
 594   if (e)                        /* Assuming chain of length 1 */
 595     {
 596       for(i=0; i<e->count; i++)
 597         {
 598           struct eattr *a = &e->attrs[i];
 599           h ^= a->id;
 600           if (a->type & EAF_EMBEDDED)
 601             h ^= a->u.data;
 602           else
 603             {
 604               struct adata *d = a->u.ptr;
 605               int size = d->length;
 606               byte *z = d->data;
 607               while (size >= 4)
 608                 {
 609                   h ^= *(u32 *)z;
 610                   z += 4;
 611                   size -= 4;
 612                 }
 613               while (size--)
 614                 h = (h >> 24) ^ (h << 8) ^ *z++;
 615             }
 616         }
 617       h ^= h >> 16;
 618       h ^= h >> 6;
 619       h &= 0xffff;
 620     }
 621   return h;
 622 }
 623
 624 /**
 625  * ea_append - concatenate &ea_list's
 626  * @to: destination list (can be %NULL)
 627  * @what: list to be appended (can be %NULL)
 628  *
 629  * This function appends the &ea_list @what at the end of
 630  * &ea_list @to and returns a pointer to the resulting list.
 631  */
 632 ea_list *
 633 ea_append(ea_list *to, ea_list *what)
 634 {
 635   ea_list *res;
 636
 637   if (!to)
 638     return what;
 639   res = to;
 640   while (to->next)
 641     to = to->next;
 642   to->next = what;
 643   return res;
 644 }
 645
 646 /*
 647  *      rta's
 648  */
 649
 650 static unsigned int rta_cache_count;
 651 static unsigned int rta_cache_size = 32;
 652 static unsigned int rta_cache_limit;
 653 static unsigned int rta_cache_mask;
 654 static rta **rta_hash_table;
 655
 656 static void
 657 rta_alloc_hash(void)
 658 {
 659   rta_hash_table = mb_allocz(rta_pool, sizeof(rta *) * rta_cache_size);
 660   if (rta_cache_size < 32768)
 661     rta_cache_limit = rta_cache_size * 2;
 662   else
 663     rta_cache_limit = ~0;
 664   rta_cache_mask = rta_cache_size - 1;
 665 }
 666
 667 static inline unsigned int
 668 rta_hash(rta *a)
 669 {
 670   return (a->proto->hash_key ^ ipa_hash(a->gw) ^
 671           mpnh_hash(a->nexthops) ^ ea_hash(a->eattrs)) & 0xffff;
 672 }
 673
 674 static inline int
 675 rta_same(rta *x, rta *y)
 676 {
 677   return (x->proto == y->proto &&
 678           x->source == y->source &&
 679           x->scope == y->scope &&
 680           x->cast == y->cast &&
 681           x->dest == y->dest &&
 682           x->flags == y->flags &&
 683           x->igp_metric == y->igp_metric &&
 684           ipa_equal(x->gw, y->gw) &&
 685           ipa_equal(x->from, y->from) &&
 686           x->iface == y->iface &&
 687           x->hostentry == y->hostentry &&
 688           mpnh_same(x->nexthops, y->nexthops) &&
 689           ea_same(x->eattrs, y->eattrs));
 690 }
 691
 692 static rta *
 693 rta_copy(rta *o)
 694 {
 695   rta *r = sl_alloc(rta_slab);
 696
 697   memcpy(r, o, sizeof(rta));
 698   r->uc = 1;
 699   r->nexthops = mpnh_copy(o->nexthops);
 700   r->eattrs = ea_list_copy(o->eattrs);
 701   return r;
 702 }
 703
 704 static inline void
 705 rta_insert(rta *r)
 706 {
 707   unsigned int h = r->hash_key & rta_cache_mask;
 708   r->next = rta_hash_table[h];
 709   if (r->next)
 710     r->next->pprev = &r->next;
 711   r->pprev = &rta_hash_table[h];
 712   rta_hash_table[h] = r;
 713 }
 714
 715 static void
 716 rta_rehash(void)
 717 {
 718   unsigned int ohs = rta_cache_size;
 719   unsigned int h;
 720   rta *r, *n;
 721   rta **oht = rta_hash_table;
 722
 723   rta_cache_size = 2*rta_cache_size;
 724   DBG("Rehashing rta cache from %d to %d entries.\n", ohs, rta_cache_size);
 725   rta_alloc_hash();
 726   for(h=0; h<ohs; h++)
 727     for(r=oht[h]; r; r=n)
 728       {
 729         n = r->next;
 730         rta_insert(r);
 731       }
 732   mb_free(oht);
 733 }
 734
 735 /**
 736  * rta_lookup - look up a &rta in attribute cache
 737  * @o: a un-cached &rta
 738  *
 739  * rta_lookup() gets an un-cached &rta structure and returns its cached
 740  * counterpart. It starts with examining the attribute cache to see whether
 741  * there exists a matching entry. If such an entry exists, it's returned and
 742  * its use count is incremented, else a new entry is created with use count
 743  * set to 1.
 744  *
 745  * The extended attribute lists attached to the &rta are automatically
 746  * converted to the normalized form.
 747  */
 748 rta *
 749 rta_lookup(rta *o)
 750 {
 751   rta *r;
 752   unsigned int h;
 753
 754   ASSERT(!(o->aflags & RTAF_CACHED));
 755   if (o->eattrs)
 756     {
 757       if (o->eattrs->next)      /* Multiple ea_list's, need to merge them */
 758         {
 759           ea_list *ml = alloca(ea_scan(o->eattrs));
 760           ea_merge(o->eattrs, ml);
 761           o->eattrs = ml;
 762         }
 763       ea_sort(o->eattrs);
 764     }
 765
 766   h = rta_hash(o);
 767   for(r=rta_hash_table[h & rta_cache_mask]; r; r=r->next)
 768     if (r->hash_key == h && rta_same(r, o))
 769       return rta_clone(r);
 770
 771   r = rta_copy(o);
 772   r->hash_key = h;
 773   r->aflags = RTAF_CACHED;
 774   rt_lock_hostentry(r->hostentry);
 775   rta_insert(r);
 776
 777   if (++rta_cache_count > rta_cache_limit)
 778     rta_rehash();
 779
 780   return r;
 781 }
 782
 783 void
 784 rta__free(rta *a)
 785 {
 786   ASSERT(rta_cache_count && (a->aflags & RTAF_CACHED));
 787   rta_cache_count--;
 788   *a->pprev = a->next;
 789   if (a->next)
 790     a->next->pprev = a->pprev;
 791   a->aflags = 0;                /* Poison the entry */
 792   rt_unlock_hostentry(a->hostentry);
 793   mpnh_free(a->nexthops);
 794   ea_free(a->eattrs);
 795   sl_free(rta_slab, a);
 796 }
 797
 798 /**
 799  * rta_dump - dump route attributes
 800  * @a: attribute structure to dump
 801  *
 802  * This function takes a &rta and dumps its contents to the debug output.
 803  */
 804 void
 805 rta_dump(rta *a)
 806 {
 807   static char *rts[] = { "RTS_DUMMY", "RTS_STATIC", "RTS_INHERIT", "RTS_DEVICE",
 808                          "RTS_STAT_DEV", "RTS_REDIR", "RTS_RIP",
 809                          "RTS_OSPF", "RTS_OSPF_IA", "RTS_OSPF_EXT1",
 810                          "RTS_OSPF_EXT2", "RTS_BGP" };
 811   static char *rtc[] = { "", " BC", " MC", " AC" };
 812   static char *rtd[] = { "", " DEV", " HOLE", " UNREACH", " PROHIBIT" };
 813
 814   debug("p=%s uc=%d %s %s%s%s h=%04x",
 815         a->proto->name, a->uc, rts[a->source], ip_scope_text(a->scope), rtc[a->cast],
 816         rtd[a->dest], a->hash_key);
 817   if (!(a->aflags & RTAF_CACHED))
 818     debug(" !CACHED");
 819   debug(" <-%I", a->from);
 820   if (a->dest == RTD_ROUTER)
 821     debug(" ->%I", a->gw);
 822   if (a->dest == RTD_DEVICE || a->dest == RTD_ROUTER)
 823     debug(" [%s]", a->iface ? a->iface->name : "???" );
 824   if (a->eattrs)
 825     {
 826       debug(" EA: ");
 827       ea_dump(a->eattrs);
 828     }
 829 }
 830
 831 /**
 832  * rta_dump_all - dump attribute cache
 833  *
 834  * This function dumps the whole contents of route attribute cache
 835  * to the debug output.
 836  */
 837 void
 838 rta_dump_all(void)
 839 {
 840   rta *a;
 841   unsigned int h;
 842
 843   debug("Route attribute cache (%d entries, rehash at %d):\n", rta_cache_count, rta_cache_limit);
 844   for(h=0; h<rta_cache_size; h++)
 845     for(a=rta_hash_table[h]; a; a=a->next)
 846       {
 847         debug("%p ", a);
 848         rta_dump(a);
 849         debug("\n");
 850       }
 851   debug("\n");
 852 }
 853
 854 void
 855 rta_show(struct cli *c, rta *a, ea_list *eal)
 856 {
 857   static char *src_names[] = { "dummy", "static", "inherit", "device", "static-device", "redirect",
 858                                "RIP", "OSPF", "OSPF-IA", "OSPF-E1", "OSPF-E2", "BGP", "pipe" };
 859   static char *cast_names[] = { "unicast", "broadcast", "multicast", "anycast" };
 860   int i;
 861
 862   cli_printf(c, -1008, "\tType: %s %s %s", src_names[a->source], cast_names[a->cast], ip_scope_text(a->scope));
 863   if (!eal)
 864     eal = a->eattrs;
 865   for(; eal; eal=eal->next)
 866     for(i=0; i<eal->count; i++)
 867       ea_show(c, &eal->attrs[i]);
 868 }
 869
 870 /**
 871  * rta_init - initialize route attribute cache
 872  *
 873  * This function is called during initialization of the routing
 874  * table module to set up the internals of the attribute cache.
 875  */
 876 void
 877 rta_init(void)
 878 {
 879   rta_pool = rp_new(&root_pool, "Attributes");
 880   rta_slab = sl_new(rta_pool, sizeof(rta));
 881   mpnh_slab = sl_new(rta_pool, sizeof(struct mpnh));
 882   rta_alloc_hash();
 883 }
 884
 885 /*
 886  *  Documentation for functions declared inline in route.h
 887  */
 888 #if 0
 889
 890 /**
 891  * rta_clone - clone route attributes
 892  * @r: a &rta to be cloned
 893  *
 894  * rta_clone() takes a cached &rta and returns its identical cached
 895  * copy. Currently it works by just returning the original &rta with
 896  * its use count incremented.
 897  */
 898 static inline rta *rta_clone(rta *r)
 899 { DUMMY; }
 900
 901 /**
 902  * rta_free - free route attributes
 903  * @r: a &rta to be freed
 904  *
 905  * If you stop using a &rta (for example when deleting a route which uses
 906  * it), you need to call rta_free() to notify the attribute cache the
 907  * attribute is no longer in use and can be freed if you were the last
 908  * user (which rta_free() tests by inspecting the use count).
 909  */
 910 static inline void rta_free(rta *r)
 911 { DUMMY; }
 912
 913 #endif