ospfd/ospf_ase.c

   1 /*
   2  * OSPF AS external route calculation.
   3  * Copyright (C) 1999, 2000 Alex Zinin, Toshiaki Takada
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <zebra.h>
  23
  24 #include "thread.h"
  25 #include "memory.h"
  26 #include "hash.h"
  27 #include "linklist.h"
  28 #include "prefix.h"
  29 #include "if.h"
  30 #include "table.h"
  31 #include "vty.h"
  32 #include "log.h"
  33
  34 #include "ospfd/ospfd.h"
  35 #include "ospfd/ospf_interface.h"
  36 #include "ospfd/ospf_ism.h"
  37 #include "ospfd/ospf_asbr.h"
  38 #include "ospfd/ospf_lsa.h"
  39 #include "ospfd/ospf_lsdb.h"
  40 #include "ospfd/ospf_neighbor.h"
  41 #include "ospfd/ospf_nsm.h"
  42 #include "ospfd/ospf_spf.h"
  43 #include "ospfd/ospf_route.h"
  44 #include "ospfd/ospf_ase.h"
  45 #include "ospfd/ospf_zebra.h"
  46 #include "ospfd/ospf_dump.h"
  47
  48 struct ospf_route *ospf_find_asbr_route(struct ospf *ospf,
  49                                         struct route_table *rtrs,
  50                                         struct prefix_ipv4 *asbr)
  51 {
  52         struct route_node *rn;
  53         struct ospf_route * or, *best = NULL;
  54         struct listnode *node;
  55         struct list *chosen;
  56
  57         /* Sanity check. */
  58         if (rtrs == NULL)
  59                 return NULL;
  60
  61         rn = route_node_lookup(rtrs, (struct prefix *)asbr);
  62         if (!rn)
  63                 return NULL;
  64
  65         route_unlock_node(rn);
  66
  67         chosen = list_new();
  68
  69         /* First try to find intra-area non-bb paths. */
  70         if (!CHECK_FLAG(ospf->config, OSPF_RFC1583_COMPATIBLE))
  71                 for (ALL_LIST_ELEMENTS_RO((struct list *)rn->info, node, or))
  72                         if (or->cost < OSPF_LS_INFINITY)
  73                                 if (!OSPF_IS_AREA_ID_BACKBONE(or->u.std.area_id)
  74                                             &&
  75                                     or->path_type == OSPF_PATH_INTRA_AREA)
  76                                         listnode_add(chosen, or);
  77
  78         /* If none is found -- look through all. */
  79         if (listcount(chosen) == 0) {
  80                 list_delete(&chosen);
  81                 chosen = rn->info;
  82         }
  83
  84         /* Now find the route with least cost. */
  85         for (ALL_LIST_ELEMENTS_RO(chosen, node, or))
  86                 if (or->cost < OSPF_LS_INFINITY) {
  87                         if (best == NULL)
  88                                 best = or ;
  89                         else if (best->cost > or->cost)
  90                                 best = or ;
  91                         else if (best->cost ==
  92                                  or->cost
  93                                            && IPV4_ADDR_CMP(
  94                                                       &best->u.std.area_id,
  95                                                       & or->u.std.area_id)
  96                                                       < 0)
  97                                 best = or ;
  98                 }
  99
 100         if (chosen != rn->info)
 101                 list_delete(&chosen);
 102
 103         return best;
 104 }
 105
 106 struct ospf_route *ospf_find_asbr_route_through_area(struct route_table *rtrs,
 107                                                      struct prefix_ipv4 *asbr,
 108                                                      struct ospf_area *area)
 109 {
 110         struct route_node *rn;
 111
 112         /* Sanity check. */
 113         if (rtrs == NULL)
 114                 return NULL;
 115
 116         rn = route_node_lookup(rtrs, (struct prefix *)asbr);
 117
 118         if (rn) {
 119                 struct listnode *node;
 120                 struct ospf_route * or ;
 121
 122                 route_unlock_node(rn);
 123
 124                 for (ALL_LIST_ELEMENTS_RO((struct list *)rn->info, node, or))
 125                         if (IPV4_ADDR_SAME(& or->u.std.area_id, &area->area_id))
 126                                 return or ;
 127         }
 128
 129         return NULL;
 130 }
 131
 132 static void ospf_ase_complete_direct_routes(struct ospf_route *ro,
 133                                             struct in_addr nexthop)
 134 {
 135         struct listnode *node;
 136         struct ospf_path *op;
 137
 138         for (ALL_LIST_ELEMENTS_RO(ro->paths, node, op))
 139                 if (op->nexthop.s_addr == INADDR_ANY)
 140                         op->nexthop.s_addr = nexthop.s_addr;
 141 }
 142
 143 static int ospf_ase_forward_address_check(struct ospf *ospf,
 144                                           struct in_addr fwd_addr)
 145 {
 146         struct listnode *ifn;
 147         struct ospf_interface *oi;
 148
 149         for (ALL_LIST_ELEMENTS_RO(ospf->oiflist, ifn, oi))
 150                 if (if_is_operative(oi->ifp))
 151                         if (oi->type != OSPF_IFTYPE_VIRTUALLINK)
 152                                 if (IPV4_ADDR_SAME(&oi->address->u.prefix4,
 153                                                    &fwd_addr))
 154                                         return 0;
 155
 156         return 1;
 157 }
 158
 159 static struct ospf_route *
 160 ospf_ase_calculate_new_route(struct ospf_lsa *lsa,
 161                              struct ospf_route *asbr_route, uint32_t metric)
 162 {
 163         struct as_external_lsa *al;
 164         struct ospf_route *new;
 165
 166         al = (struct as_external_lsa *)lsa->data;
 167
 168         new = ospf_route_new();
 169
 170         /* Set redistributed type -- does make sense? */
 171         /* new->type = type; */
 172         new->id = al->header.id;
 173         new->mask = al->mask;
 174
 175         if (!IS_EXTERNAL_METRIC(al->e[0].tos)) {
 176                 if (IS_DEBUG_OSPF(lsa, LSA))
 177                         zlog_debug("Route[External]: type-1 created.");
 178                 new->path_type = OSPF_PATH_TYPE1_EXTERNAL;
 179                 new->cost = asbr_route->cost + metric; /* X + Y */
 180         } else {
 181                 if (IS_DEBUG_OSPF(lsa, LSA))
 182                         zlog_debug("Route[External]: type-2 created.");
 183                 new->path_type = OSPF_PATH_TYPE2_EXTERNAL;
 184                 new->cost = asbr_route->cost;   /* X */
 185                 new->u.ext.type2_cost = metric; /* Y */
 186         }
 187
 188         new->type = OSPF_DESTINATION_NETWORK;
 189         new->u.ext.origin = lsa;
 190         new->u.ext.tag = ntohl(al->e[0].route_tag);
 191         new->u.ext.asbr = asbr_route;
 192
 193         assert(new != asbr_route);
 194
 195         return new;
 196 }
 197
 198 #define OSPF_ASE_CALC_INTERVAL 1
 199
 200 int ospf_ase_calculate_route(struct ospf *ospf, struct ospf_lsa *lsa)
 201 {
 202         uint32_t metric;
 203         struct as_external_lsa *al;
 204         struct ospf_route *asbr_route;
 205         struct prefix_ipv4 asbr, p;
 206         struct route_node *rn;
 207         struct ospf_route *new, * or ;
 208         int ret;
 209
 210         assert(lsa);
 211         al = (struct as_external_lsa *)lsa->data;
 212
 213         if (lsa->data->type == OSPF_AS_NSSA_LSA)
 214                 if (IS_DEBUG_OSPF_NSSA)
 215                         zlog_debug("ospf_ase_calc(): Processing Type-7");
 216
 217         /* Stay away from any Local Translated Type-7 LSAs */
 218         if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT)) {
 219                 if (IS_DEBUG_OSPF_NSSA)
 220                         zlog_debug("ospf_ase_calc(): Rejecting Local Xlt'd");
 221                 return 0;
 222         }
 223
 224         if (IS_DEBUG_OSPF(lsa, LSA)) {
 225                 zlog_debug(
 226                         "Route[External]: Calculate AS-external-LSA to %pI4/%d adv_router %pI4",
 227                         &al->header.id, ip_masklen(al->mask),
 228                         &al->header.adv_router);
 229         }
 230
 231         /* (1) If the cost specified by the LSA is LSInfinity, or if the
 232                LSA's LS age is equal to MaxAge, then examine the next LSA. */
 233         if ((metric = GET_METRIC(al->e[0].metric)) >= OSPF_LS_INFINITY) {
 234                 if (IS_DEBUG_OSPF(lsa, LSA))
 235                         zlog_debug(
 236                                 "Route[External]: Metric is OSPF_LS_INFINITY");
 237                 return 0;
 238         }
 239         if (IS_LSA_MAXAGE(lsa)) {
 240                 if (IS_DEBUG_OSPF(lsa, LSA))
 241                         zlog_debug(
 242                                 "Route[External]: AS-external-LSA is MAXAGE");
 243                 return 0;
 244         }
 245
 246         /* (2) If the LSA was originated by the calculating router itself,
 247            examine the next LSA. */
 248         if (IS_LSA_SELF(lsa)) {
 249                 if (IS_DEBUG_OSPF(lsa, LSA))
 250                         zlog_debug(
 251                                 "Route[External]: AS-external-LSA is self originated");
 252                 return 0;
 253         }
 254
 255         /* (3) Call the destination described by the LSA N.  N's address is
 256                obtained by masking the LSA's Link State ID with the
 257                network/subnet mask contained in the body of the LSA.  Look
 258                up the routing table entries (potentially one per attached
 259                area) for the AS boundary router (ASBR) that originated the
 260                LSA. If no entries exist for router ASBR (i.e., ASBR is
 261                unreachable), do nothing with this LSA and consider the next
 262                in the list. */
 263
 264         asbr.family = AF_INET;
 265         asbr.prefix = al->header.adv_router;
 266         asbr.prefixlen = IPV4_MAX_BITLEN;
 267         apply_mask_ipv4(&asbr);
 268
 269         asbr_route = ospf_find_asbr_route(ospf, ospf->new_rtrs, &asbr);
 270         if (asbr_route == NULL) {
 271                 if (IS_DEBUG_OSPF(lsa, LSA))
 272                         zlog_debug(
 273                                 "Route[External]: Can't find originating ASBR route");
 274                 return 0;
 275         }
 276         if (!(asbr_route->u.std.flags & ROUTER_LSA_EXTERNAL)) {
 277                 if (IS_DEBUG_OSPF(lsa, LSA))
 278                         zlog_debug(
 279                                 "Route[External]: Originating router is not an ASBR");
 280                 return 0;
 281         }
 282
 283         /*     Else, this LSA describes an AS external path to destination
 284                N.  Examine the forwarding address specified in the AS-
 285                external-LSA.  This indicates the IP address to which
 286                packets for the destination should be forwarded. */
 287
 288         if (al->e[0].fwd_addr.s_addr == INADDR_ANY) {
 289                 /* If the forwarding address is set to 0.0.0.0, packets should
 290                    be sent to the ASBR itself. Among the multiple routing table
 291                    entries for the ASBR, select the preferred entry as follows.
 292                    If RFC1583Compatibility is set to "disabled", prune the set
 293                    of routing table entries for the ASBR as described in
 294                    Section 16.4.1. In any case, among the remaining routing
 295                    table entries, select the routing table entry with the least
 296                    cost; when there are multiple least cost routing table
 297                    entries the entry whose associated area has the largest OSPF
 298                    Area ID (when considered as an unsigned 32-bit integer) is
 299                    chosen. */
 300
 301                 /* asbr_route already contains the requested route */
 302         } else {
 303                 /* If the forwarding address is non-zero, look up the
 304                    forwarding address in the routing table.[24] The matching
 305                    routing table entry must specify an intra-area or inter-area
 306                    path; if no such path exists, do nothing with the LSA and
 307                    consider the next in the list. */
 308                 if (!ospf_ase_forward_address_check(ospf, al->e[0].fwd_addr)) {
 309                         if (IS_DEBUG_OSPF(lsa, LSA))
 310                                 zlog_debug(
 311                                         "Route[External]: Forwarding address is our router address");
 312                         return 0;
 313                 }
 314
 315                 asbr.family = AF_INET;
 316                 asbr.prefix = al->e[0].fwd_addr;
 317                 asbr.prefixlen = IPV4_MAX_BITLEN;
 318
 319                 rn = route_node_match(ospf->new_table, (struct prefix *)&asbr);
 320
 321                 if (rn == NULL || (asbr_route = rn->info) == NULL) {
 322                         if (IS_DEBUG_OSPF(lsa, LSA))
 323                                 zlog_debug(
 324                                         "Route[External]: Can't find route to forwarding address");
 325                         if (rn)
 326                                 route_unlock_node(rn);
 327                         return 0;
 328                 }
 329
 330                 route_unlock_node(rn);
 331         }
 332
 333         /* (4) Let X be the cost specified by the preferred routing table
 334                entry for the ASBR/forwarding address, and Y the cost
 335                specified in the LSA.  X is in terms of the link state
 336                metric, and Y is a type 1 or 2 external metric. */
 337
 338
 339         /* (5) Look up the routing table entry for the destination N.  If
 340                no entry exists for N, install the AS external path to N,
 341                with next hop equal to the list of next hops to the
 342                forwarding address, and advertising router equal to ASBR.
 343                If the external metric type is 1, then the path-type is set
 344                to type 1 external and the cost is equal to X+Y.  If the
 345                external metric type is 2, the path-type is set to type 2
 346                external, the link state component of the route's cost is X,
 347                and the type 2 cost is Y. */
 348         new = ospf_ase_calculate_new_route(lsa, asbr_route, metric);
 349
 350         /* (6) Compare the AS external path described by the LSA with the
 351                existing paths in N's routing table entry, as follows. If
 352                the new path is preferred, it replaces the present paths in
 353                N's routing table entry.  If the new path is of equal
 354                preference, it is added to N's routing table entry's list of
 355                paths. */
 356
 357         /* Set prefix. */
 358         p.family = AF_INET;
 359         p.prefix = al->header.id;
 360         p.prefixlen = ip_masklen(al->mask);
 361
 362         /* if there is a Intra/Inter area route to the N
 363            do not install external route */
 364         if ((rn = route_node_lookup(ospf->new_table, (struct prefix *)&p))) {
 365                 route_unlock_node(rn);
 366                 if (rn->info == NULL)
 367                         zlog_info("Route[External]: rn->info NULL");
 368                 if (new)
 369                         ospf_route_free(new);
 370                 return 0;
 371         }
 372         /* Find a route to the same dest */
 373         /* If there is no route, create new one. */
 374         if ((rn = route_node_lookup(ospf->new_external_route,
 375                                     (struct prefix *)&p)))
 376                 route_unlock_node(rn);
 377
 378         if (!rn || (or = rn->info) == NULL) {
 379                 if (IS_DEBUG_OSPF(lsa, LSA))
 380                         zlog_debug("Route[External]: Adding a new route %pFX with paths %u",
 381                                    &p, listcount(asbr_route->paths));
 382
 383                 ospf_route_add(ospf->new_external_route, &p, new, asbr_route);
 384
 385                 if (al->e[0].fwd_addr.s_addr != INADDR_ANY)
 386                         ospf_ase_complete_direct_routes(new, al->e[0].fwd_addr);
 387                 return 0;
 388         } else {
 389                 /* (a) Intra-area and inter-area paths are always preferred
 390                        over AS external paths.
 391
 392                    (b) Type 1 external paths are always preferred over type 2
 393                        external paths. When all paths are type 2 external
 394                        paths, the paths with the smallest advertised type 2
 395                        metric are always preferred. */
 396                 ret = ospf_route_cmp(ospf, new, or);
 397
 398                 /*     (c) If the new AS external path is still
 399                    indistinguishable
 400                            from the current paths in the N's routing table
 401                    entry,
 402                            and RFC1583Compatibility is set to "disabled", select
 403                            the preferred paths based on the intra-AS paths to
 404                    the
 405                            ASBR/forwarding addresses, as specified in Section
 406                            16.4.1.
 407
 408                        (d) If the new AS external path is still
 409                    indistinguishable
 410                            from the current paths in the N's routing table
 411                    entry,
 412                            select the preferred path based on a least cost
 413                            comparison.  Type 1 external paths are compared by
 414                            looking at the sum of the distance to the forwarding
 415                            address and the advertised type 1 metric (X+Y).  Type
 416                    2
 417                            external paths advertising equal type 2 metrics are
 418                            compared by looking at the distance to the forwarding
 419                            addresses.
 420                 */
 421                 /* New route is better */
 422                 if (ret < 0) {
 423                         if (IS_DEBUG_OSPF(lsa, LSA))
 424                                 zlog_debug(
 425                                         "Route[External]: New route is better");
 426                         ospf_route_subst(rn, new, asbr_route);
 427                         if (al->e[0].fwd_addr.s_addr != INADDR_ANY)
 428                                 ospf_ase_complete_direct_routes(
 429                                         new, al->e[0].fwd_addr);
 430                         or = new;
 431                         new = NULL;
 432                 }
 433                 /* Old route is better */
 434                 else if (ret > 0) {
 435                         if (IS_DEBUG_OSPF(lsa, LSA))
 436                                 zlog_debug(
 437                                         "Route[External]: Old route is better");
 438                         /* do nothing */
 439                 }
 440                 /* Routes are equal */
 441                 else {
 442                         if (IS_DEBUG_OSPF(lsa, LSA))
 443                                 zlog_debug("Route[External]: Routes are equal");
 444                         ospf_route_copy_nexthops(or, asbr_route->paths);
 445                         if (al->e[0].fwd_addr.s_addr != INADDR_ANY)
 446                                 ospf_ase_complete_direct_routes(
 447                                         or, al->e[0].fwd_addr);
 448                 }
 449         }
 450         /* Make sure setting newly calculated ASBR route.*/
 451         or->u.ext.asbr = asbr_route;
 452         if (new)
 453                 ospf_route_free(new);
 454
 455         lsa->route = or ;
 456         return 0;
 457 }
 458
 459 static int ospf_ase_route_match_same(struct route_table *rt,
 460                                      struct prefix *prefix,
 461                                      struct ospf_route *newor)
 462 {
 463         struct route_node *rn;
 464         struct ospf_route *or;
 465         struct ospf_path *op;
 466         struct ospf_path *newop;
 467         struct listnode *n1;
 468         struct listnode *n2;
 469
 470         if (!rt || !prefix)
 471                 return 0;
 472
 473         rn = route_node_lookup(rt, prefix);
 474         if (!rn)
 475                 return 0;
 476
 477         route_unlock_node(rn);
 478
 479         or = rn->info;
 480
 481         assert(or);
 482
 483         if (or->path_type != newor->path_type)
 484                 return 0;
 485
 486         switch (or->path_type) {
 487         case OSPF_PATH_TYPE1_EXTERNAL:
 488                 if (or->cost != newor->cost)
 489                         return 0;
 490                 break;
 491         case OSPF_PATH_TYPE2_EXTERNAL:
 492                 if ((or->cost != newor->cost)
 493                     || (or->u.ext.type2_cost != newor->u.ext.type2_cost))
 494                         return 0;
 495                 break;
 496         default:
 497                 assert(0);
 498                 return 0;
 499         }
 500
 501         assert(or->paths);
 502
 503         if (or->paths->count != newor->paths->count)
 504                 return 0;
 505
 506         /* Check each path. */
 507         for (n1 = listhead(or->paths), n2 = listhead(newor->paths); n1 && n2;
 508              n1 = listnextnode_unchecked(n1), n2 = listnextnode_unchecked(n2)) {
 509                 op = listgetdata(n1);
 510                 newop = listgetdata(n2);
 511
 512                 if (!IPV4_ADDR_SAME(&op->nexthop, &newop->nexthop))
 513                         return 0;
 514                 if (op->ifindex != newop->ifindex)
 515                         return 0;
 516         }
 517
 518         if (or->u.ext.tag != newor->u.ext.tag)
 519                 return 0;
 520
 521         return 1;
 522 }
 523
 524 static int ospf_ase_compare_tables(struct ospf *ospf,
 525                                    struct route_table *new_external_route,
 526                                    struct route_table *old_external_route)
 527 {
 528         struct route_node *rn, *new_rn;
 529         struct ospf_route * or ;
 530
 531         /* Remove deleted routes */
 532         for (rn = route_top(old_external_route); rn; rn = route_next(rn))
 533                 if ((or = rn->info)) {
 534                         if (!(new_rn = route_node_lookup(new_external_route,
 535                                                          &rn->p)))
 536                                 ospf_zebra_delete(
 537                                         ospf, (struct prefix_ipv4 *)&rn->p, or);
 538                         else
 539                                 route_unlock_node(new_rn);
 540                 }
 541
 542
 543         /* Install new routes */
 544         for (rn = route_top(new_external_route); rn; rn = route_next(rn))
 545                 if ((or = rn->info) != NULL)
 546                         if (!ospf_ase_route_match_same(old_external_route,
 547                                                        &rn->p, or))
 548                                 ospf_zebra_add(
 549                                         ospf, (struct prefix_ipv4 *)&rn->p, or);
 550
 551         return 0;
 552 }
 553
 554 static int ospf_ase_calculate_timer(struct thread *t)
 555 {
 556         struct ospf *ospf;
 557         struct ospf_lsa *lsa;
 558         struct route_node *rn;
 559         struct listnode *node;
 560         struct ospf_area *area;
 561         struct timeval start_time, stop_time;
 562
 563         ospf = THREAD_ARG(t);
 564         ospf->t_ase_calc = NULL;
 565
 566         if (ospf->ase_calc) {
 567                 ospf->ase_calc = 0;
 568
 569                 monotime(&start_time);
 570
 571                 /* Calculate external route for each AS-external-LSA */
 572                 LSDB_LOOP (EXTERNAL_LSDB(ospf), rn, lsa)
 573                         ospf_ase_calculate_route(ospf, lsa);
 574
 575                 /*  This version simple adds to the table all NSSA areas  */
 576                 if (ospf->anyNSSA)
 577                         for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, area)) {
 578                                 if (IS_DEBUG_OSPF_NSSA)
 579                                         zlog_debug(
 580                                                 "ospf_ase_calculate_timer(): looking at area %pI4",
 581                                                 &area->area_id);
 582
 583                                 if (area->external_routing == OSPF_AREA_NSSA)
 584                                         LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
 585                                                 ospf_ase_calculate_route(ospf,
 586                                                                          lsa);
 587                         }
 588                 /* kevinm: And add the NSSA routes in ospf_top */
 589                 LSDB_LOOP (NSSA_LSDB(ospf), rn, lsa)
 590                         ospf_ase_calculate_route(ospf, lsa);
 591
 592                 /* Compare old and new external routing table and install the
 593                    difference info zebra/kernel */
 594                 ospf_ase_compare_tables(ospf, ospf->new_external_route,
 595                                         ospf->old_external_route);
 596
 597                 /* Delete old external routing table */
 598                 ospf_route_table_free(ospf->old_external_route);
 599                 ospf->old_external_route = ospf->new_external_route;
 600                 ospf->new_external_route = route_table_init();
 601
 602                 monotime(&stop_time);
 603
 604                 if (IS_DEBUG_OSPF_EVENT)
 605                         zlog_info(
 606                                 "SPF Processing Time(usecs): External Routes: %lld",
 607                                 (stop_time.tv_sec - start_time.tv_sec)
 608                                                 * 1000000LL
 609                                         + (stop_time.tv_usec
 610                                            - start_time.tv_usec));
 611         }
 612         return 0;
 613 }
 614
 615 void ospf_ase_calculate_schedule(struct ospf *ospf)
 616 {
 617         if (ospf == NULL)
 618                 return;
 619
 620         ospf->ase_calc = 1;
 621 }
 622
 623 void ospf_ase_calculate_timer_add(struct ospf *ospf)
 624 {
 625         if (ospf == NULL)
 626                 return;
 627
 628         thread_add_timer(master, ospf_ase_calculate_timer, ospf,
 629                          OSPF_ASE_CALC_INTERVAL, &ospf->t_ase_calc);
 630 }
 631
 632 void ospf_ase_register_external_lsa(struct ospf_lsa *lsa, struct ospf *top)
 633 {
 634         struct route_node *rn;
 635         struct prefix_ipv4 p;
 636         struct list *lst;
 637         struct as_external_lsa *al;
 638
 639         al = (struct as_external_lsa *)lsa->data;
 640         p.family = AF_INET;
 641         p.prefix = lsa->data->id;
 642         p.prefixlen = ip_masklen(al->mask);
 643         apply_mask_ipv4(&p);
 644
 645         rn = route_node_get(top->external_lsas, (struct prefix *)&p);
 646         if ((lst = rn->info) == NULL)
 647                 rn->info = lst = list_new();
 648         else
 649                 route_unlock_node(rn);
 650
 651         /* We assume that if LSA is deleted from DB
 652            is is also deleted from this RT */
 653         listnode_add(lst, ospf_lsa_lock(lsa)); /* external_lsas lst */
 654 }
 655
 656 void ospf_ase_unregister_external_lsa(struct ospf_lsa *lsa, struct ospf *top)
 657 {
 658         struct route_node *rn;
 659         struct prefix_ipv4 p;
 660         struct list *lst;
 661         struct as_external_lsa *al;
 662
 663         al = (struct as_external_lsa *)lsa->data;
 664         p.family = AF_INET;
 665         p.prefix = lsa->data->id;
 666         p.prefixlen = ip_masklen(al->mask);
 667         apply_mask_ipv4(&p);
 668
 669         rn = route_node_lookup(top->external_lsas, (struct prefix *)&p);
 670
 671         if (rn) {
 672                 lst = rn->info;
 673                 struct listnode *node = listnode_lookup(lst, lsa);
 674                 /* Unlock lsa only if node is present in the list */
 675                 if (node) {
 676                         listnode_delete(lst, lsa);
 677                         ospf_lsa_unlock(&lsa); /* external_lsas list */
 678                 }
 679
 680                 route_unlock_node(rn);
 681         }
 682 }
 683
 684 void ospf_ase_external_lsas_finish(struct route_table *rt)
 685 {
 686         struct route_node *rn;
 687         struct ospf_lsa *lsa;
 688         struct list *lst;
 689         struct listnode *node, *nnode;
 690
 691         for (rn = route_top(rt); rn; rn = route_next(rn))
 692                 if ((lst = rn->info) != NULL) {
 693                         for (ALL_LIST_ELEMENTS(lst, node, nnode, lsa))
 694                                 ospf_lsa_unlock(&lsa); /* external_lsas lst */
 695                         list_delete(&lst);
 696                 }
 697
 698         route_table_finish(rt);
 699 }
 700
 701 void ospf_ase_incremental_update(struct ospf *ospf, struct ospf_lsa *lsa)
 702 {
 703         struct list *lsas;
 704         struct listnode *node;
 705         struct route_node *rn, *rn2;
 706         struct prefix_ipv4 p;
 707         struct route_table *tmp_old;
 708         struct as_external_lsa *al;
 709
 710         al = (struct as_external_lsa *)lsa->data;
 711         p.family = AF_INET;
 712         p.prefix = lsa->data->id;
 713         p.prefixlen = ip_masklen(al->mask);
 714         apply_mask_ipv4(&p);
 715
 716         /* if new_table is NULL, there was no spf calculation, thus
 717            incremental update is unneeded */
 718         if (!ospf->new_table)
 719                 return;
 720
 721         /* If there is already an intra-area or inter-area route
 722            to the destination, no recalculation is necessary
 723            (internal routes take precedence). */
 724
 725         rn = route_node_lookup(ospf->new_table, (struct prefix *)&p);
 726         if (rn) {
 727                 route_unlock_node(rn);
 728                 if (rn->info)
 729                         return;
 730         }
 731
 732         rn = route_node_lookup(ospf->external_lsas, (struct prefix *)&p);
 733         assert(rn);
 734         assert(rn->info);
 735         lsas = rn->info;
 736         route_unlock_node(rn);
 737
 738         for (ALL_LIST_ELEMENTS_RO(lsas, node, lsa))
 739                 ospf_ase_calculate_route(ospf, lsa);
 740
 741         /* prepare temporary old routing table for compare */
 742         tmp_old = route_table_init();
 743         rn = route_node_lookup(ospf->old_external_route, (struct prefix *)&p);
 744         if (rn && rn->info) {
 745                 rn2 = route_node_get(tmp_old, (struct prefix *)&p);
 746                 rn2->info = rn->info;
 747                 route_unlock_node(rn);
 748         }
 749
 750         /* install changes to zebra */
 751         ospf_ase_compare_tables(ospf, ospf->new_external_route, tmp_old);
 752
 753         /* update ospf->old_external_route table */
 754         if (rn && rn->info)
 755                 ospf_route_free((struct ospf_route *)rn->info);
 756
 757         rn2 = route_node_lookup(ospf->new_external_route, (struct prefix *)&p);
 758         /* if new route exists, install it to ospf->old_external_route */
 759         if (rn2 && rn2->info) {
 760                 if (!rn)
 761                         rn = route_node_get(ospf->old_external_route,
 762                                             (struct prefix *)&p);
 763                 rn->info = rn2->info;
 764         } else {
 765                 /* remove route node from ospf->old_external_route */
 766                 if (rn) {
 767                         rn->info = NULL;
 768                         route_unlock_node(rn);
 769                 }
 770         }
 771
 772         if (rn2) {
 773                 /* rn2->info is stored in route node of ospf->old_external_route
 774                  */
 775                 rn2->info = NULL;
 776                 route_unlock_node(rn2);
 777                 route_unlock_node(rn2);
 778         }
 779
 780         route_table_finish(tmp_old);
 781 }