diff options
Diffstat (limited to 'ospfd/ospf_ia.c')
| -rw-r--r-- | ospfd/ospf_ia.c | 668 |
1 files changed, 668 insertions, 0 deletions
diff --git a/ospfd/ospf_ia.c b/ospfd/ospf_ia.c new file mode 100644 index 0000000..59112b2 --- /dev/null +++ b/ospfd/ospf_ia.c @@ -0,0 +1,668 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * OSPF inter-area routing. + * Copyright (C) 1999, 2000 Alex Zinin, Toshiaki Takada + */ + + +#include <zebra.h> + +#include "frrevent.h" +#include "memory.h" +#include "hash.h" +#include "linklist.h" +#include "prefix.h" +#include "table.h" +#include "log.h" + +#include "ospfd/ospfd.h" +#include "ospfd/ospf_interface.h" +#include "ospfd/ospf_ism.h" +#include "ospfd/ospf_asbr.h" +#include "ospfd/ospf_lsa.h" +#include "ospfd/ospf_lsdb.h" +#include "ospfd/ospf_neighbor.h" +#include "ospfd/ospf_nsm.h" +#include "ospfd/ospf_spf.h" +#include "ospfd/ospf_route.h" +#include "ospfd/ospf_ase.h" +#include "ospfd/ospf_abr.h" +#include "ospfd/ospf_ia.h" +#include "ospfd/ospf_dump.h" + +static struct ospf_route *ospf_find_abr_route(struct route_table *rtrs, + struct prefix_ipv4 *abr, + struct ospf_area *area) +{ + struct route_node *rn; + struct ospf_route * or ; + struct listnode *node; + + if ((rn = route_node_lookup(rtrs, (struct prefix *)abr)) == NULL) + return NULL; + + route_unlock_node(rn); + + for (ALL_LIST_ELEMENTS_RO((struct list *)rn->info, node, or)) + if (IPV4_ADDR_SAME(& or->u.std.area_id, &area->area_id) + && (or->u.std.flags & ROUTER_LSA_BORDER)) + return or ; + + return NULL; +} + +static void ospf_ia_network_route(struct ospf *ospf, struct route_table *rt, + struct prefix_ipv4 *p, + struct ospf_route *new_or, + struct ospf_route *abr_or) +{ + struct route_node *rn1; + struct ospf_route * or ; + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: processing summary route to %pFX", __func__, p); + + /* Find a route to the same dest */ + if ((rn1 = route_node_lookup(rt, (struct prefix *)p))) { + int res; + + route_unlock_node(rn1); + + if ((or = rn1->info)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: Found a route to the same network", + __func__); + /* Check the existing route. */ + if ((res = ospf_route_cmp(ospf, new_or, or)) < 0) { + /* New route is better, so replace old one. */ + ospf_route_subst(rn1, new_or, abr_or); + } else if (res == 0) { + /* New and old route are equal, so next hops can + * be added. */ + route_lock_node(rn1); + ospf_route_copy_nexthops(or, abr_or->paths); + route_unlock_node(rn1); + + /* new route can be deleted, because existing + * route has been updated. */ + ospf_route_free(new_or); + } else { + /* New route is worse, so free it. */ + ospf_route_free(new_or); + return; + } + } /* if (or)*/ + } /*if (rn1)*/ + else { /* no route */ + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: add new route to %pFX", __func__, p); + ospf_route_add(rt, p, new_or, abr_or); + } +} + +static void ospf_ia_router_route(struct ospf *ospf, struct route_table *rtrs, + struct prefix_ipv4 *p, + struct ospf_route *new_or, + struct ospf_route *abr_or) +{ + struct ospf_route * or = NULL; + struct route_node *rn; + int ret; + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: considering %pFX", __func__, p); + + /* Find a route to the same dest */ + rn = route_node_get(rtrs, (struct prefix *)p); + + if (rn->info == NULL) + /* This is a new route */ + rn->info = list_new(); + else { + struct ospf_area *or_area; + or_area = ospf_area_lookup_by_area_id(ospf, + new_or->u.std.area_id); + assert(or_area); + /* This is an additional route */ + route_unlock_node(rn); + or = ospf_find_asbr_route_through_area(rtrs, p, or_area); + } + + if (or) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: a route to the same ABR through the same area exists", + __func__); + /* New route is better */ + if ((ret = ospf_route_cmp(ospf, new_or, or)) < 0) { + listnode_delete(rn->info, or); + ospf_route_free(or); + /* proceed down */ + } + /* Routes are the same */ + else if (ret == 0) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: merging the new route", + __func__); + + ospf_route_copy_nexthops(or, abr_or->paths); + ospf_route_free(new_or); + return; + } + /* New route is worse */ + else { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: skipping the new route", + __func__); + ospf_route_free(new_or); + return; + } + } + + ospf_route_copy_nexthops(new_or, abr_or->paths); + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: adding the new route", __func__); + + listnode_add(rn->info, new_or); +} + + +static int process_summary_lsa(struct ospf_area *area, struct route_table *rt, + struct route_table *rtrs, struct ospf_lsa *lsa) +{ + struct ospf *ospf = area->ospf; + struct ospf_area_range *range; + struct ospf_route *abr_or, *new_or; + struct summary_lsa *sl; + struct prefix_ipv4 p, abr; + uint32_t metric; + + if (lsa == NULL) + return 0; + + sl = (struct summary_lsa *)lsa->data; + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: LS ID: %pI4", __func__, &sl->header.id); + + metric = GET_METRIC(sl->metric); + + if (metric == OSPF_LS_INFINITY) + return 0; + + if (IS_LSA_MAXAGE(lsa)) + return 0; + + if (ospf_lsa_is_self_originated(area->ospf, lsa)) + return 0; + + p.family = AF_INET; + p.prefix = sl->header.id; + + if (sl->header.type == OSPF_SUMMARY_LSA) + p.prefixlen = ip_masklen(sl->mask); + else + p.prefixlen = IPV4_MAX_BITLEN; + + apply_mask_ipv4(&p); + + if (sl->header.type == OSPF_SUMMARY_LSA + && (range = ospf_area_range_match_any(ospf, &p)) + && ospf_area_range_active(range)) + return 0; + + /* XXX: This check seems dubious to me. If an ABR has already decided + * to consider summaries received in this area, then why would one wish + * to exclude default? + */ + if (IS_OSPF_ABR(ospf) && ospf->abr_type != OSPF_ABR_STAND + && area->external_routing != OSPF_AREA_DEFAULT + && p.prefix.s_addr == OSPF_DEFAULT_DESTINATION && p.prefixlen == 0) + return 0; /* Ignore summary default from a stub area */ + + abr.family = AF_INET; + abr.prefix = sl->header.adv_router; + abr.prefixlen = IPV4_MAX_BITLEN; + apply_mask_ipv4(&abr); + + abr_or = ospf_find_abr_route(rtrs, &abr, area); + + if (abr_or == NULL) + return 0; + + new_or = ospf_route_new(); + new_or->type = OSPF_DESTINATION_NETWORK; + new_or->id = sl->header.id; + new_or->mask = sl->mask; + new_or->u.std.options = sl->header.options; + new_or->u.std.origin = (struct lsa_header *)sl; + new_or->cost = abr_or->cost + metric; + new_or->u.std.area_id = area->area_id; + new_or->u.std.external_routing = area->external_routing; + new_or->path_type = OSPF_PATH_INTER_AREA; + + if (sl->header.type == OSPF_SUMMARY_LSA) + ospf_ia_network_route(ospf, rt, &p, new_or, abr_or); + else { + new_or->type = OSPF_DESTINATION_ROUTER; + new_or->u.std.flags = ROUTER_LSA_EXTERNAL; + ospf_ia_router_route(ospf, rtrs, &p, new_or, abr_or); + } + + return 0; +} + +static void ospf_examine_summaries(struct ospf_area *area, + struct route_table *lsdb_rt, + struct route_table *rt, + struct route_table *rtrs) +{ + struct ospf_lsa *lsa; + struct route_node *rn; + + LSDB_LOOP (lsdb_rt, rn, lsa) + process_summary_lsa(area, rt, rtrs, lsa); +} + +int ospf_area_is_transit(struct ospf_area *area) +{ + return (area->transit == OSPF_TRANSIT_TRUE) + || ospf_full_virtual_nbrs( + area); /* Cisco forgets to set the V-bit :( */ +} + +static void ospf_update_network_route(struct ospf *ospf, struct route_table *rt, + struct route_table *rtrs, + struct summary_lsa *lsa, + struct prefix_ipv4 *p, + struct ospf_area *area) +{ + struct route_node *rn; + struct ospf_route * or, *abr_or, *new_or; + struct prefix_ipv4 abr; + uint32_t cost; + + abr.family = AF_INET; + abr.prefix = lsa->header.adv_router; + abr.prefixlen = IPV4_MAX_BITLEN; + apply_mask_ipv4(&abr); + + abr_or = ospf_find_abr_route(rtrs, &abr, area); + + if (abr_or == NULL) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: can't find a route to the ABR", + __func__); + return; + } + + cost = abr_or->cost + GET_METRIC(lsa->metric); + + rn = route_node_lookup(rt, (struct prefix *)p); + + if (!rn) { + if (ospf->abr_type != OSPF_ABR_SHORTCUT) + return; /* Standard ABR can update only already + installed + backbone paths */ + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: Allowing Shortcut ABR to add new route", + __func__); + new_or = ospf_route_new(); + new_or->type = OSPF_DESTINATION_NETWORK; + new_or->id = lsa->header.id; + new_or->mask = lsa->mask; + new_or->u.std.options = lsa->header.options; + new_or->u.std.origin = (struct lsa_header *)lsa; + new_or->cost = cost; + new_or->u.std.area_id = area->area_id; + new_or->u.std.external_routing = area->external_routing; + new_or->path_type = OSPF_PATH_INTER_AREA; + ospf_route_add(rt, p, new_or, abr_or); + + return; + } else { + route_unlock_node(rn); + if (rn->info == NULL) + return; + } + + or = rn->info; + + if (or->path_type != OSPF_PATH_INTRA_AREA && + or->path_type != OSPF_PATH_INTER_AREA) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: ERR: path type is wrong", __func__); + return; + } + + if (ospf->abr_type == OSPF_ABR_SHORTCUT) { + if ( + or->path_type == OSPF_PATH_INTRA_AREA + && !OSPF_IS_AREA_ID_BACKBONE( + or->u.std.area_id)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: Shortcut: this intra-area path is not backbone", + __func__); + return; + } + } else /* Not Shortcut ABR */ + { + if (!OSPF_IS_AREA_ID_BACKBONE(or->u.std.area_id)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: route is not BB-associated", + __func__); + return; /* We can update only BB routes */ + } + } + + if (or->cost < cost) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: new route is worse", __func__); + return; + } + + if (or->cost == cost) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: new route is same distance, adding nexthops", + __func__); + ospf_route_copy_nexthops(or, abr_or->paths); + } + + if (or->cost > cost) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: new route is better, overriding nexthops", + __func__); + ospf_route_subst_nexthops(or, abr_or->paths); + or->cost = cost; + + if ((ospf->abr_type == OSPF_ABR_SHORTCUT) + && !OSPF_IS_AREA_ID_BACKBONE(or->u.std.area_id)) { + or->path_type = OSPF_PATH_INTER_AREA; + or->u.std.area_id = area->area_id; + or->u.std.external_routing = area->external_routing; + /* Note that we can do this only in Shortcut ABR mode, + because standard ABR must leave the route type and + area + unchanged + */ + } + } +} + +static void ospf_update_router_route(struct ospf *ospf, + struct route_table *rtrs, + struct summary_lsa *lsa, + struct prefix_ipv4 *p, + struct ospf_area *area) +{ + struct ospf_route * or, *abr_or, *new_or; + struct prefix_ipv4 abr; + uint32_t cost; + + abr.family = AF_INET; + abr.prefix = lsa->header.adv_router; + abr.prefixlen = IPV4_MAX_BITLEN; + apply_mask_ipv4(&abr); + + abr_or = ospf_find_abr_route(rtrs, &abr, area); + + if (abr_or == NULL) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: can't find a route to the ABR", + __func__); + return; + } + + cost = abr_or->cost + GET_METRIC(lsa->metric); + + /* First try to find a backbone path, + because standard ABR can update only BB-associated paths */ + + if ((ospf->backbone == NULL) && (ospf->abr_type != OSPF_ABR_SHORTCUT)) + return; /* no BB area, not Shortcut ABR, exiting */ + + /* find the backbone route, if possible */ + if ((ospf->backbone == NULL) + || !(or = ospf_find_asbr_route_through_area(rtrs, p, + ospf->backbone))) { + if (ospf->abr_type != OSPF_ABR_SHORTCUT) + + /* route to ASBR through the BB not found + the router is not Shortcut ABR, exiting */ + + return; + else + /* We're a Shortcut ABR*/ + { + /* Let it either add a new router or update the route + through the same (non-BB) area. */ + + new_or = ospf_route_new(); + new_or->type = OSPF_DESTINATION_ROUTER; + new_or->id = lsa->header.id; + new_or->mask = lsa->mask; + new_or->u.std.options = lsa->header.options; + new_or->u.std.origin = (struct lsa_header *)lsa; + new_or->cost = cost; + new_or->u.std.area_id = area->area_id; + new_or->u.std.external_routing = area->external_routing; + new_or->path_type = OSPF_PATH_INTER_AREA; + new_or->u.std.flags = ROUTER_LSA_EXTERNAL; + ospf_ia_router_route(ospf, rtrs, p, new_or, abr_or); + + return; + } + } + + /* At this point the "or" is always bb-associated */ + + if (!(or->u.std.flags & ROUTER_LSA_EXTERNAL)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: the remote router is not an ASBR", + __func__); + return; + } + + if (or->path_type != OSPF_PATH_INTRA_AREA && + or->path_type != OSPF_PATH_INTER_AREA) + return; + + if (or->cost < cost) + return; + + else if (or->cost == cost) + ospf_route_copy_nexthops(or, abr_or->paths); + + else if (or->cost > cost) { + ospf_route_subst_nexthops(or, abr_or->paths); + or->cost = cost; + + /* Even if the ABR runs in Shortcut mode, we can't change + the path type and area, because the "or" is always + bb-associated + at this point and even Shortcut ABR can't change these + attributes */ + } +} + +static int process_transit_summary_lsa(struct ospf_area *area, + struct route_table *rt, + struct route_table *rtrs, + struct ospf_lsa *lsa) +{ + struct ospf *ospf = area->ospf; + struct summary_lsa *sl; + struct prefix_ipv4 p; + uint32_t metric; + + if (lsa == NULL) + return 0; + + sl = (struct summary_lsa *)lsa->data; + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: LS ID: %pI4", __func__, &lsa->data->id); + metric = GET_METRIC(sl->metric); + + if (metric == OSPF_LS_INFINITY) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: metric is infinity, skip", __func__); + return 0; + } + + if (IS_LSA_MAXAGE(lsa)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: This LSA is too old", __func__); + return 0; + } + + if (ospf_lsa_is_self_originated(area->ospf, lsa)) { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s: This LSA is mine, skip", __func__); + return 0; + } + + p.family = AF_INET; + p.prefix = sl->header.id; + + if (sl->header.type == OSPF_SUMMARY_LSA) + p.prefixlen = ip_masklen(sl->mask); + else + p.prefixlen = IPV4_MAX_BITLEN; + + apply_mask_ipv4(&p); + + if (sl->header.type == OSPF_SUMMARY_LSA) + ospf_update_network_route(ospf, rt, rtrs, sl, &p, area); + else + ospf_update_router_route(ospf, rtrs, sl, &p, area); + + return 0; +} + +static void ospf_examine_transit_summaries(struct ospf_area *area, + struct route_table *lsdb_rt, + struct route_table *rt, + struct route_table *rtrs) +{ + struct ospf_lsa *lsa; + struct route_node *rn; + + LSDB_LOOP (lsdb_rt, rn, lsa) + process_transit_summary_lsa(area, rt, rtrs, lsa); +} + +void ospf_ia_routing(struct ospf *ospf, struct route_table *rt, + struct route_table *rtrs) +{ + struct listnode *node; + struct ospf_area *area; + + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:start", __func__); + + if (IS_OSPF_ABR(ospf)) { + switch (ospf->abr_type) { + case OSPF_ABR_STAND: + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:Standard ABR", __func__); + + if ((area = ospf->backbone)) { + if (IS_DEBUG_OSPF_EVENT) { + zlog_debug( + "%s:backbone area found, examining summaries", + __func__); + } + + OSPF_EXAMINE_SUMMARIES_ALL(area, rt, rtrs); + + for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, + area)) + if (area != ospf->backbone) + if (ospf_area_is_transit(area)) + OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL( + area, rt, rtrs); + } else if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:backbone area NOT found", + __func__); + break; + case OSPF_ABR_IBM: + case OSPF_ABR_CISCO: + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:Alternative Cisco/IBM ABR", + __func__); + area = ospf->backbone; /* Find the BB */ + + /* If we have an active BB connection */ + if (area && ospf_act_bb_connection(ospf)) { + if (IS_DEBUG_OSPF_EVENT) { + zlog_debug( + "%s: backbone area found, examining BB summaries", + __func__); + } + + OSPF_EXAMINE_SUMMARIES_ALL(area, rt, rtrs); + + for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, + area)) + if (area != ospf->backbone) + if (ospf_area_is_transit(area)) + OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL( + area, rt, rtrs); + } else { /* No active BB connection--consider all areas + */ + if (IS_DEBUG_OSPF_EVENT) + zlog_debug( + "%s: Active BB connection not found", + __func__); + for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, + area)) + OSPF_EXAMINE_SUMMARIES_ALL(area, rt, + rtrs); + } + break; + case OSPF_ABR_SHORTCUT: + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:Alternative Shortcut", __func__); + area = ospf->backbone; /* Find the BB */ + + /* If we have an active BB connection */ + if (area && ospf_act_bb_connection(ospf)) { + if (IS_DEBUG_OSPF_EVENT) { + zlog_debug( + "%s: backbone area found, examining BB summaries", + __func__); + } + OSPF_EXAMINE_SUMMARIES_ALL(area, rt, rtrs); + } + + for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, area)) + if (area != ospf->backbone) + if (ospf_area_is_transit(area) + || ((area->shortcut_configured + != OSPF_SHORTCUT_DISABLE) + && ((ospf->backbone == NULL) + || ((area->shortcut_configured + == OSPF_SHORTCUT_ENABLE) + && area->shortcut_capability)))) + OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL( + area, rt, rtrs); + break; + default: + break; + } + } else { + if (IS_DEBUG_OSPF_EVENT) + zlog_debug("%s:not ABR, considering all areas", + __func__); + + for (ALL_LIST_ELEMENTS_RO(ospf->areas, node, area)) + OSPF_EXAMINE_SUMMARIES_ALL(area, rt, rtrs); + } +} |