blob: 5ced71ca16ae6cfd86ebeee3460206e12cc218c3 [file] [log] [blame]
/* OSPF SPF calculation.
Copyright (C) 1999, 2000 Kunihiro Ishiguro, Toshiaki Takada
This file is part of GNU Zebra.
GNU Zebra is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
GNU Zebra is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Zebra; see the file COPYING. If not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
#include <zebra.h>
#include "thread.h"
#include "memory.h"
#include "hash.h"
#include "linklist.h"
#include "prefix.h"
#include "if.h"
#include "table.h"
#include "log.h"
#include "sockunion.h" /* for inet_ntop () */
#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_ia.h"
#include "ospfd/ospf_ase.h"
#include "ospfd/ospf_abr.h"
#include "ospfd/ospf_dump.h"
#define DEBUG
struct vertex_nexthop *
vertex_nexthop_new (struct vertex *parent)
{
struct vertex_nexthop *new;
new = XCALLOC (MTYPE_OSPF_NEXTHOP, sizeof (struct vertex_nexthop));
new->parent = parent;
return new;
}
void
vertex_nexthop_free (struct vertex_nexthop *nh)
{
XFREE (MTYPE_OSPF_NEXTHOP, nh);
}
struct vertex_nexthop *
vertex_nexthop_dup (struct vertex_nexthop *nh)
{
struct vertex_nexthop *new;
new = vertex_nexthop_new (nh->parent);
new->oi = nh->oi;
new->router = nh->router;
return new;
}
struct vertex *
ospf_vertex_new (struct ospf_lsa *lsa)
{
struct vertex *new;
new = XMALLOC (MTYPE_OSPF_VERTEX, sizeof (struct vertex));
memset (new, 0, sizeof (struct vertex));
new->flags = 0;
new->type = lsa->data->type;
new->id = lsa->data->id;
new->lsa = lsa->data;
new->distance = 0;
new->child = list_new ();
new->nexthop = list_new ();
return new;
}
void
ospf_vertex_free (struct vertex *v)
{
listnode node;
list_delete (v->child);
if (listcount (v->nexthop) > 0)
for (node = listhead (v->nexthop); node; nextnode (node))
vertex_nexthop_free (node->data);
list_delete (v->nexthop);
XFREE (MTYPE_OSPF_VERTEX, v);
}
void
ospf_vertex_add_parent (struct vertex *v)
{
struct vertex_nexthop *nh;
listnode node;
for (node = listhead (v->nexthop); node; nextnode (node))
{
nh = (struct vertex_nexthop *) getdata (node);
/* No need to add two links from the same parent. */
if (listnode_lookup (nh->parent->child, v) == NULL)
listnode_add (nh->parent->child, v);
}
}
void
ospf_spf_init (struct ospf_area *area)
{
struct vertex *v;
/* Create root node. */
v = ospf_vertex_new (area->router_lsa_self);
area->spf = v;
/* Reset ABR and ASBR router counts. */
area->abr_count = 0;
area->asbr_count = 0;
}
int
ospf_spf_has_vertex (struct route_table *rv, struct route_table *nv,
struct lsa_header *lsa)
{
struct prefix p;
struct route_node *rn;
p.family = AF_INET;
p.prefixlen = IPV4_MAX_BITLEN;
p.u.prefix4 = lsa->id;
if (lsa->type == OSPF_ROUTER_LSA)
rn = route_node_get (rv, &p);
else
rn = route_node_get (nv, &p);
if (rn->info != NULL)
{
route_unlock_node (rn);
return 1;
}
return 0;
}
listnode
ospf_vertex_lookup (list vlist, struct in_addr id, int type)
{
listnode node;
struct vertex *v;
for (node = listhead (vlist); node; nextnode (node))
{
v = (struct vertex *) getdata (node);
if (IPV4_ADDR_SAME (&id, &v->id) && type == v->type)
return node;
}
return NULL;
}
int
ospf_lsa_has_link (struct lsa_header *w, struct lsa_header *v)
{
int i;
int length;
struct router_lsa *rl;
struct network_lsa *nl;
/* In case of W is Network LSA. */
if (w->type == OSPF_NETWORK_LSA)
{
if (v->type == OSPF_NETWORK_LSA)
return 0;
nl = (struct network_lsa *) w;
length = (ntohs (w->length) - OSPF_LSA_HEADER_SIZE - 4) / 4;
for (i = 0; i < length; i++)
if (IPV4_ADDR_SAME (&nl->routers[i], &v->id))
return 1;
return 0;
}
/* In case of W is Router LSA. */
if (w->type == OSPF_ROUTER_LSA)
{
rl = (struct router_lsa *) w;
length = ntohs (w->length);
for (i = 0;
i < ntohs (rl->links) && length >= sizeof (struct router_lsa);
i++, length -= 12)
{
switch (rl->link[i].type)
{
case LSA_LINK_TYPE_POINTOPOINT:
case LSA_LINK_TYPE_VIRTUALLINK:
/* Router LSA ID. */
if (v->type == OSPF_ROUTER_LSA &&
IPV4_ADDR_SAME (&rl->link[i].link_id, &v->id))
{
return 1;
}
break;
case LSA_LINK_TYPE_TRANSIT:
/* Network LSA ID. */
if (v->type == OSPF_NETWORK_LSA &&
IPV4_ADDR_SAME (&rl->link[i].link_id, &v->id))
{
return 1;
}
break;
case LSA_LINK_TYPE_STUB:
/* Not take into count? */
continue;
default:
break;
}
}
}
return 0;
}
/* Add the nexthop to the list, only if it is unique.
* If it's not unique, free the nexthop entry.
*/
void
ospf_nexthop_add_unique (struct vertex_nexthop *new, list nexthop)
{
struct vertex_nexthop *nh;
listnode node;
int match;
match = 0;
for (node = listhead (nexthop); node; nextnode (node))
{
nh = node->data;
/* Compare the two entries. */
/* XXX
* Comparing the parent preserves the shortest path tree
* structure even when the nexthops are identical.
*/
if (nh->oi == new->oi &&
IPV4_ADDR_SAME (&nh->router, &new->router) &&
nh->parent == new->parent)
{
match = 1;
break;
}
}
if (!match)
listnode_add (nexthop, new);
else
vertex_nexthop_free (new);
}
/* Merge entries in list b into list a. */
void
ospf_nexthop_merge (list a, list b)
{
struct listnode *n;
for (n = listhead (b); n; nextnode (n))
{
ospf_nexthop_add_unique (n->data, a);
}
}
#define ROUTER_LSA_MIN_SIZE 12
#define ROUTER_LSA_TOS_SIZE 4
struct router_lsa_link *
ospf_get_next_link (struct vertex *v, struct vertex *w,
struct router_lsa_link *prev_link)
{
u_char *p;
u_char *lim;
struct router_lsa_link *l;
if (prev_link == NULL)
p = ((u_char *) v->lsa) + 24;
else
{
p = (u_char *) prev_link;
p += (ROUTER_LSA_MIN_SIZE +
(prev_link->m[0].tos_count * ROUTER_LSA_TOS_SIZE));
}
lim = ((u_char *) v->lsa) + ntohs (v->lsa->length);
while (p < lim)
{
l = (struct router_lsa_link *) p;
p += (ROUTER_LSA_MIN_SIZE + (l->m[0].tos_count * ROUTER_LSA_TOS_SIZE));
if (l->m[0].type == LSA_LINK_TYPE_STUB)
continue;
/* Defer NH calculation via VLs until summaries from
transit areas area confidered */
if (l->m[0].type == LSA_LINK_TYPE_VIRTUALLINK)
continue;
if (IPV4_ADDR_SAME (&l->link_id, &w->id))
return l;
}
return NULL;
}
/* Consider supplied next-hop for inclusion to the supplied list
* of next-hops, adjust list as neccessary
*/
void
ospf_spf_consider_nexthop (struct list *nexthops,
struct vertex_nexthop *newhop)
{
struct listnode *nnode;
struct vertex_nexthop *hop;
LIST_LOOP (nexthops, hop, nnode)
{
assert (hop->oi);
/* weed out hops with higher cost than the newhop */
if (hop->oi->output_cost > newhop->oi->output_cost)
{
/* delete the existing nexthop */
listnode_delete (nexthops, hop);
vertex_nexthop_free (hop);
}
else if (hop->oi->output_cost < newhop->oi->output_cost)
{
return;
}
}
/* new hop is <= existing hops, add it */
listnode_add (nexthops, newhop);
return;
}
/* Calculate nexthop from root to vertex W. */
void
ospf_nexthop_calculation (struct ospf_area *area,
struct vertex *v, struct vertex *w)
{
listnode node;
struct vertex_nexthop *nh, *x;
struct ospf_interface *oi = NULL;
struct router_lsa_link *l = NULL;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_nexthop_calculation(): Start");
/* W's parent is root. */
if (v == area->spf)
{
if (w->type == OSPF_VERTEX_ROUTER)
{
while ((l = ospf_get_next_link (v, w, l)))
{
struct router_lsa_link *l2 = NULL;
if (l->m[0].type == LSA_LINK_TYPE_POINTOPOINT)
{
/* Check for PtMP, signified by PtP link V->W
with link_data our PtMP interface. */
oi = ospf_if_is_configured (area->ospf, &l->link_data);
if (oi && oi->type == OSPF_IFTYPE_POINTOMULTIPOINT)
{
struct prefix_ipv4 la;
la.prefixlen = oi->address->prefixlen;
/* We link to them on PtMP interface
- find the interface on w */
while ((l2 = ospf_get_next_link (w, v, l2)))
{
la.prefix = l2->link_data;
if (prefix_cmp ((struct prefix *) &la,
oi->address) == 0)
/* link_data is on our PtMP network */
break;
}
}
else
{
while ((l2 = ospf_get_next_link (w, v, l2)))
{
oi = ospf_if_is_configured (area->ospf,
&(l2->link_data));
if (oi == NULL)
continue;
if (!IPV4_ADDR_SAME (&oi->address->u.prefix4,
&l->link_data))
continue;
break;
}
}
if (oi && l2)
{
nh = vertex_nexthop_new (v);
nh->oi = oi;
nh->router = l2->link_data;
ospf_spf_consider_nexthop (w->nexthop, nh);
}
}
}
}
else
{
while ((l = ospf_get_next_link (v, w, l)))
{
oi = ospf_if_is_configured (area->ospf, &(l->link_data));
if (oi)
{
nh = vertex_nexthop_new (v);
nh->oi = oi;
nh->router.s_addr = 0;
listnode_add (w->nexthop, nh);
}
}
}
return;
}
/* In case of W's parent is network connected to root. */
else if (v->type == OSPF_VERTEX_NETWORK)
{
for (node = listhead (v->nexthop); node; nextnode (node))
{
x = (struct vertex_nexthop *) getdata (node);
if (x->parent == area->spf)
{
while ((l = ospf_get_next_link (w, v, l)))
{
nh = vertex_nexthop_new (v);
nh->oi = x->oi;
nh->router = l->link_data;
listnode_add (w->nexthop, nh);
}
return;
}
}
}
/* Inherit V's nexthop. */
for (node = listhead (v->nexthop); node; nextnode (node))
{
nh = vertex_nexthop_dup (node->data);
nh->parent = v;
ospf_nexthop_add_unique (nh, w->nexthop);
}
}
void
ospf_install_candidate (list candidate, struct vertex *w)
{
listnode node;
struct vertex *cw;
if (list_isempty (candidate))
{
listnode_add (candidate, w);
return;
}
/* Install vertex with sorting by distance. */
for (node = listhead (candidate); node; nextnode (node))
{
cw = (struct vertex *) getdata (node);
if (cw->distance > w->distance)
{
list_add_node_prev (candidate, node, w);
break;
}
else if (node->next == NULL)
{
list_add_node_next (candidate, node, w);
break;
}
}
}
/* RFC2328 Section 16.1 (2). */
void
ospf_spf_next (struct vertex *v, struct ospf_area *area,
list candidate, struct route_table *rv, struct route_table *nv)
{
struct ospf_lsa *w_lsa = NULL;
struct vertex *w, *cw;
u_char *p;
u_char *lim;
struct router_lsa_link *l = NULL;
struct in_addr *r;
listnode node;
int type = 0;
/* If this is a router-LSA, and bit V of the router-LSA (see Section
A.4.2:RFC2328) is set, set Area A's TransitCapability to TRUE. */
if (v->type == OSPF_VERTEX_ROUTER)
{
if (IS_ROUTER_LSA_VIRTUAL ((struct router_lsa *) v->lsa))
area->transit = OSPF_TRANSIT_TRUE;
}
p = ((u_char *) v->lsa) + OSPF_LSA_HEADER_SIZE + 4;
lim = ((u_char *) v->lsa) + ntohs (v->lsa->length);
while (p < lim)
{
/* In case of V is Router-LSA. */
if (v->lsa->type == OSPF_ROUTER_LSA)
{
l = (struct router_lsa_link *) p;
p += (ROUTER_LSA_MIN_SIZE +
(l->m[0].tos_count * ROUTER_LSA_TOS_SIZE));
/* (a) If this is a link to a stub network, examine the next
link in V's LSA. Links to stub networks will be
considered in the second stage of the shortest path
calculation. */
if ((type = l->m[0].type) == LSA_LINK_TYPE_STUB)
continue;
/* (b) Otherwise, W is a transit vertex (router or transit
network). Look up the vertex W's LSA (router-LSA or
network-LSA) in Area A's link state database. */
switch (type)
{
case LSA_LINK_TYPE_POINTOPOINT:
case LSA_LINK_TYPE_VIRTUALLINK:
if (type == LSA_LINK_TYPE_VIRTUALLINK)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("looking up LSA through VL: %s",
inet_ntoa (l->link_id));
}
w_lsa = ospf_lsa_lookup (area, OSPF_ROUTER_LSA, l->link_id,
l->link_id);
if (w_lsa)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("found the LSA");
}
break;
case LSA_LINK_TYPE_TRANSIT:
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("Looking up Network LSA, ID: %s",
inet_ntoa (l->link_id));
w_lsa = ospf_lsa_lookup_by_id (area, OSPF_NETWORK_LSA,
l->link_id);
if (w_lsa)
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("found the LSA");
break;
default:
zlog_warn ("Invalid LSA link type %d", type);
continue;
}
}
else
{
/* In case of V is Network-LSA. */
r = (struct in_addr *) p;
p += sizeof (struct in_addr);
/* Lookup the vertex W's LSA. */
w_lsa = ospf_lsa_lookup_by_id (area, OSPF_ROUTER_LSA, *r);
}
/* (b cont.) If the LSA does not exist, or its LS age is equal
to MaxAge, or it does not have a link back to vertex V,
examine the next link in V's LSA.[23] */
if (w_lsa == NULL)
continue;
if (IS_LSA_MAXAGE (w_lsa))
continue;
if (!ospf_lsa_has_link (w_lsa->data, v->lsa))
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("The LSA doesn't have a link back");
continue;
}
/* (c) If vertex W is already on the shortest-path tree, examine
the next link in the LSA. */
if (ospf_spf_has_vertex (rv, nv, w_lsa->data))
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("The LSA is already in SPF");
continue;
}
/* (d) Calculate the link state cost D of the resulting path
from the root to vertex W. D is equal to the sum of the link
state cost of the (already calculated) shortest path to
vertex V and the advertised cost of the link between vertices
V and W. If D is: */
/* prepare vertex W. */
w = ospf_vertex_new (w_lsa);
/* calculate link cost D. */
if (v->lsa->type == OSPF_ROUTER_LSA)
w->distance = v->distance + ntohs (l->m[0].metric);
else
w->distance = v->distance;
/* Is there already vertex W in candidate list? */
node = ospf_vertex_lookup (candidate, w->id, w->type);
if (node == NULL)
{
/* Calculate nexthop to W. */
ospf_nexthop_calculation (area, v, w);
ospf_install_candidate (candidate, w);
}
else
{
cw = (struct vertex *) getdata (node);
/* if D is greater than. */
if (cw->distance < w->distance)
{
ospf_vertex_free (w);
continue;
}
/* equal to. */
else if (cw->distance == w->distance)
{
/* Calculate nexthop to W. */
ospf_nexthop_calculation (area, v, w);
ospf_nexthop_merge (cw->nexthop, w->nexthop);
list_delete_all_node (w->nexthop);
ospf_vertex_free (w);
}
/* less than. */
else
{
/* Calculate nexthop. */
ospf_nexthop_calculation (area, v, w);
/* Remove old vertex from candidate list. */
ospf_vertex_free (cw);
listnode_delete (candidate, cw);
/* Install new to candidate. */
ospf_install_candidate (candidate, w);
}
}
}
}
/* Add vertex V to SPF tree. */
void
ospf_spf_register (struct vertex *v, struct route_table *rv,
struct route_table *nv)
{
struct prefix p;
struct route_node *rn;
p.family = AF_INET;
p.prefixlen = IPV4_MAX_BITLEN;
p.u.prefix4 = v->id;
if (v->type == OSPF_VERTEX_ROUTER)
rn = route_node_get (rv, &p);
else
rn = route_node_get (nv, &p);
rn->info = v;
}
void
ospf_spf_route_free (struct route_table *table)
{
struct route_node *rn;
struct vertex *v;
for (rn = route_top (table); rn; rn = route_next (rn))
{
if ((v = rn->info))
{
ospf_vertex_free (v);
rn->info = NULL;
}
route_unlock_node (rn);
}
route_table_finish (table);
}
void
ospf_spf_dump (struct vertex *v, int i)
{
listnode cnode;
listnode nnode;
struct vertex_nexthop *nexthop;
if (v->type == OSPF_VERTEX_ROUTER)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF Result: %d [R] %s", i, inet_ntoa (v->lsa->id));
}
else
{
struct network_lsa *lsa = (struct network_lsa *) v->lsa;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF Result: %d [N] %s/%d", i, inet_ntoa (v->lsa->id),
ip_masklen (lsa->mask));
for (nnode = listhead (v->nexthop); nnode; nextnode (nnode))
{
nexthop = getdata (nnode);
if (IS_DEBUG_OSPF_EVENT)
zlog_info (" nexthop %s", inet_ntoa (nexthop->router));
}
}
i++;
for (cnode = listhead (v->child); cnode; nextnode (cnode))
{
v = getdata (cnode);
ospf_spf_dump (v, i);
}
}
/* Second stage of SPF calculation. */
void
ospf_spf_process_stubs (struct ospf_area *area, struct vertex *v,
struct route_table *rt)
{
listnode cnode;
struct vertex *child;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_process_stub():processing stubs for area %s",
inet_ntoa (area->area_id));
if (v->type == OSPF_VERTEX_ROUTER)
{
u_char *p;
u_char *lim;
struct router_lsa_link *l;
struct router_lsa *rlsa;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_process_stub():processing router LSA, id: %s",
inet_ntoa (v->lsa->id));
rlsa = (struct router_lsa *) v->lsa;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_process_stub(): we have %d links to process",
ntohs (rlsa->links));
p = ((u_char *) v->lsa) + 24;
lim = ((u_char *) v->lsa) + ntohs (v->lsa->length);
while (p < lim)
{
l = (struct router_lsa_link *) p;
p += (ROUTER_LSA_MIN_SIZE +
(l->m[0].tos_count * ROUTER_LSA_TOS_SIZE));
if (l->m[0].type == LSA_LINK_TYPE_STUB)
ospf_intra_add_stub (rt, l, v, area);
}
}
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("children of V:");
for (cnode = listhead (v->child); cnode; nextnode (cnode))
{
child = getdata (cnode);
if (IS_DEBUG_OSPF_EVENT)
zlog_info (" child : %s", inet_ntoa (child->id));
}
for (cnode = listhead (v->child); cnode; nextnode (cnode))
{
child = getdata (cnode);
if (CHECK_FLAG (child->flags, OSPF_VERTEX_PROCESSED))
continue;
ospf_spf_process_stubs (area, child, rt);
SET_FLAG (child->flags, OSPF_VERTEX_PROCESSED);
}
}
void
ospf_rtrs_free (struct route_table *rtrs)
{
struct route_node *rn;
list or_list;
listnode node;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("Route: Router Routing Table free");
for (rn = route_top (rtrs); rn; rn = route_next (rn))
if ((or_list = rn->info) != NULL)
{
for (node = listhead (or_list); node; nextnode (node))
ospf_route_free (node->data);
list_delete (or_list);
/* Unlock the node. */
rn->info = NULL;
route_unlock_node (rn);
}
route_table_finish (rtrs);
}
void
ospf_rtrs_print (struct route_table *rtrs)
{
struct route_node *rn;
list or_list;
listnode ln;
listnode pnode;
struct ospf_route *or;
struct ospf_path *path;
char buf1[BUFSIZ];
char buf2[BUFSIZ];
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_rtrs_print() start");
for (rn = route_top (rtrs); rn; rn = route_next (rn))
if ((or_list = rn->info) != NULL)
for (ln = listhead (or_list); ln; nextnode (ln))
{
or = getdata (ln);
switch (or->path_type)
{
case OSPF_PATH_INTRA_AREA:
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("%s [%d] area: %s",
inet_ntop (AF_INET, &or->id, buf1, BUFSIZ),
or->cost, inet_ntop (AF_INET, &or->u.std.area_id,
buf2, BUFSIZ));
break;
case OSPF_PATH_INTER_AREA:
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("%s IA [%d] area: %s",
inet_ntop (AF_INET, &or->id, buf1, BUFSIZ),
or->cost, inet_ntop (AF_INET, &or->u.std.area_id,
buf2, BUFSIZ));
break;
default:
break;
}
for (pnode = listhead (or->paths); pnode; nextnode (pnode))
{
path = getdata (pnode);
if (path->nexthop.s_addr == 0)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info (" directly attached to %s\r\n",
IF_NAME (path->oi));
}
else
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info (" via %s, %s\r\n",
inet_ntoa (path->nexthop), IF_NAME (path->oi));
}
}
}
zlog_info ("ospf_rtrs_print() end");
}
/* Calculating the shortest-path tree for an area. */
void
ospf_spf_calculate (struct ospf_area *area, struct route_table *new_table,
struct route_table *new_rtrs)
{
list candidate;
listnode node;
struct vertex *v;
struct route_table *rv;
struct route_table *nv;
if (IS_DEBUG_OSPF_EVENT)
{
zlog_info ("ospf_spf_calculate: Start");
zlog_info ("ospf_spf_calculate: running Dijkstra for area %s",
inet_ntoa (area->area_id));
}
/* Check router-lsa-self. If self-router-lsa is not yet allocated,
return this area's calculation. */
if (!area->router_lsa_self)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_spf_calculate: "
"Skip area %s's calculation due to empty router_lsa_self",
inet_ntoa (area->area_id));
return;
}
/* RFC2328 16.1. (1). */
/* Initialize the algorithm's data structures. */
rv = route_table_init ();
nv = route_table_init ();
/* Clear the list of candidate vertices. */
candidate = list_new ();
/* Initialize the shortest-path tree to only the root (which is the
router doing the calculation). */
ospf_spf_init (area);
v = area->spf;
ospf_spf_register (v, rv, nv);
/* Set Area A's TransitCapability to FALSE. */
area->transit = OSPF_TRANSIT_FALSE;
area->shortcut_capability = 1;
for (;;)
{
/* RFC2328 16.1. (2). */
ospf_spf_next (v, area, candidate, rv, nv);
/* RFC2328 16.1. (3). */
/* If at this step the candidate list is empty, the shortest-
path tree (of transit vertices) has been completely built and
this stage of the procedure terminates. */
if (listcount (candidate) == 0)
break;
/* Otherwise, choose the vertex belonging to the candidate list
that is closest to the root, and add it to the shortest-path
tree (removing it from the candidate list in the
process). */
node = listhead (candidate);
v = getdata (node);
ospf_vertex_add_parent (v);
/* Reveve from the candidate list. */
listnode_delete (candidate, v);
/* Add to SPF tree. */
ospf_spf_register (v, rv, nv);
/* Note that when there is a choice of vertices closest to the
root, network vertices must be chosen before router vertices
in order to necessarily find all equal-cost paths. */
/* We don't do this at this moment, we should add the treatment
above codes. -- kunihiro. */
/* RFC2328 16.1. (4). */
if (v->type == OSPF_VERTEX_ROUTER)
ospf_intra_add_router (new_rtrs, v, area);
else
ospf_intra_add_transit (new_table, v, area);
/* RFC2328 16.1. (5). */
/* Iterate the algorithm by returning to Step 2. */
}
if (IS_DEBUG_OSPF_EVENT)
{
ospf_spf_dump (area->spf, 0);
ospf_route_table_dump (new_table);
}
/* Second stage of SPF calculation procedure's */
ospf_spf_process_stubs (area, area->spf, new_table);
/* Free all vertices which allocated for SPF calculation */
ospf_spf_route_free (rv);
ospf_spf_route_free (nv);
/* Free candidate list */
list_free (candidate);
/* Increment SPF Calculation Counter. */
area->spf_calculation++;
area->ospf->ts_spf = time (NULL);
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("ospf_spf_calculate: Stop");
}
/* Timer for SPF calculation. */
int
ospf_spf_calculate_timer (struct thread *thread)
{
struct ospf *ospf = THREAD_ARG (thread);
struct route_table *new_table, *new_rtrs;
listnode node;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF: Timer (SPF calculation expire)");
ospf->t_spf_calc = NULL;
/* Allocate new table tree. */
new_table = route_table_init ();
new_rtrs = route_table_init ();
ospf_vl_unapprove (ospf);
/* Calculate SPF for each area. */
for (node = listhead (ospf->areas); node; node = nextnode (node))
ospf_spf_calculate (node->data, new_table, new_rtrs);
ospf_vl_shut_unapproved (ospf);
ospf_ia_routing (ospf, new_table, new_rtrs);
ospf_prune_unreachable_networks (new_table);
ospf_prune_unreachable_routers (new_rtrs);
/* AS-external-LSA calculation should not be performed here. */
/* If new Router Route is installed,
then schedule re-calculate External routes. */
if (1)
ospf_ase_calculate_schedule (ospf);
ospf_ase_calculate_timer_add (ospf);
/* Update routing table. */
ospf_route_install (ospf, new_table);
/* Update ABR/ASBR routing table */
if (ospf->old_rtrs)
{
/* old_rtrs's node holds linked list of ospf_route. --kunihiro. */
/* ospf_route_delete (ospf->old_rtrs); */
ospf_rtrs_free (ospf->old_rtrs);
}
ospf->old_rtrs = ospf->new_rtrs;
ospf->new_rtrs = new_rtrs;
if (IS_OSPF_ABR (ospf))
ospf_abr_task (ospf);
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF: calculation complete");
return 0;
}
/* Add schedule for SPF calculation. To avoid frequenst SPF calc, we
set timer for SPF calc. */
void
ospf_spf_calculate_schedule (struct ospf *ospf)
{
time_t ht, delay;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF: calculation timer scheduled");
/* OSPF instance does not exist. */
if (ospf == NULL)
return;
/* SPF calculation timer is already scheduled. */
if (ospf->t_spf_calc)
{
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF: calculation timer is already scheduled: %p",
ospf->t_spf_calc);
return;
}
ht = time (NULL) - ospf->ts_spf;
/* Get SPF calculation delay time. */
if (ht < ospf->spf_holdtime)
{
if (ospf->spf_holdtime - ht < ospf->spf_delay)
delay = ospf->spf_delay;
else
delay = ospf->spf_holdtime - ht;
}
else
delay = ospf->spf_delay;
if (IS_DEBUG_OSPF_EVENT)
zlog_info ("SPF: calculation timer delay = %ld", (long)delay);
ospf->t_spf_calc =
thread_add_timer (master, ospf_spf_calculate_timer, ospf, delay);
}