static char *
ospf6_lsdesc_backlink (struct ospf6_lsa *lsa,
caddr_t lsdesc, struct ospf6_vertex *v)
{
caddr_t backlink, found = NULL;
int size;
size = (OSPF6_LSA_IS_TYPE (ROUTER, lsa) ?
sizeof (struct ospf6_router_lsdesc) :
sizeof (struct ospf6_network_lsdesc));
for (backlink = OSPF6_LSA_HEADER_END (lsa->header) + 4;
backlink + size <= OSPF6_LSA_END (lsa->header); backlink += size)
{
assert (! (OSPF6_LSA_IS_TYPE (NETWORK, lsa) &&
VERTEX_IS_TYPE (NETWORK, v)));
if (OSPF6_LSA_IS_TYPE (NETWORK, lsa) &&
NETWORK_LSDESC_GET_NBR_ROUTERID (backlink)
== v->lsa->header->adv_router)
found = backlink;
else if (VERTEX_IS_TYPE (NETWORK, v) &&
ROUTER_LSDESC_IS_TYPE (TRANSIT_NETWORK, backlink) &&
ROUTER_LSDESC_GET_NBR_ROUTERID (backlink)
== v->lsa->header->adv_router &&
ROUTER_LSDESC_GET_NBR_IFID (backlink)
== ntohl (v->lsa->header->id))
found = backlink;
else
{
if (! ROUTER_LSDESC_IS_TYPE (POINTTOPOINT, backlink) ||
! ROUTER_LSDESC_IS_TYPE (POINTTOPOINT, lsdesc))
continue;
if (ROUTER_LSDESC_GET_NBR_IFID (backlink) !=
ROUTER_LSDESC_GET_IFID (lsdesc) ||
ROUTER_LSDESC_GET_NBR_IFID (lsdesc) !=
ROUTER_LSDESC_GET_IFID (backlink))
continue;
if (ROUTER_LSDESC_GET_NBR_ROUTERID (backlink) !=
v->lsa->header->adv_router ||
ROUTER_LSDESC_GET_NBR_ROUTERID (lsdesc) !=
lsa->header->adv_router)
continue;
found = backlink;
}
}
if (IS_OSPF6_SIBLING_DEBUG_SPF)
zlog_debug (" Backlink %s", (found ? "OK" : "FAIL"));
return found;
}
static void
ospf6_nexthop_calc (struct ospf6_vertex *w, struct ospf6_vertex *v,
caddr_t lsdesc)
{
int i;
ifindex_t ifindex;
struct ospf6_interface *oi;
u_int16_t type;
u_int32_t adv_router;
struct ospf6_lsa *lsa;
struct ospf6_link_lsa *link_lsa;
char buf[64];
assert (VERTEX_IS_TYPE (ROUTER, w));
ifindex = (VERTEX_IS_TYPE (NETWORK, v) ? v->nexthop[0].ifindex :
/* v is the local router & the interface_id is a local ifindex */
(ifindex_t) ROUTER_LSDESC_GET_IFID (lsdesc));
assert (ifindex >= 0);
oi = ospf6_interface_lookup_by_ifindex (ifindex);
if (oi == NULL)
{
if (IS_OSPF6_DEBUG_SPF (PROCESS))
zlog_debug ("Can't find interface in SPF: ifindex %d", ifindex);
return;
}
type = htons (OSPF6_LSTYPE_LINK);
adv_router = (VERTEX_IS_TYPE (NETWORK, v) ?
NETWORK_LSDESC_GET_NBR_ROUTERID (lsdesc) :
ROUTER_LSDESC_GET_NBR_ROUTERID (lsdesc));
i = 0;
for (lsa = ospf6_lsdb_type_router_head (type, adv_router, oi->lsdb); lsa;
lsa = ospf6_lsdb_type_router_next (type, adv_router, lsa))
{
if (VERTEX_IS_TYPE (ROUTER, v) &&
htonl (ROUTER_LSDESC_GET_NBR_IFID (lsdesc)) != lsa->header->id)
continue;
link_lsa = (struct ospf6_link_lsa *) OSPF6_LSA_HEADER_END (lsa->header);
if (IS_OSPF6_DEBUG_SPF (PROCESS))
{
inet_ntop (AF_INET6, &link_lsa->linklocal_addr, buf, sizeof (buf));
zlog_debug (" nexthop %s from %s", buf, lsa->name);
}
if (i < OSPF6_MULTI_PATH_LIMIT)
{
memcpy (&w->nexthop[i].address, &link_lsa->linklocal_addr,
sizeof (struct in6_addr));
w->nexthop[i].ifindex = ifindex;
i++;
}
}
if (i == 0 && IS_OSPF6_DEBUG_SPF (PROCESS))
zlog_debug ("No nexthop for %s found", w->name);
}
/* RFC2740 3.8.1. Calculating the shortest path tree for an area */
void ospf6_spf_calculation(u_int32_t router_id,
struct ospf6_route_table * result_table,
struct ospf6_area * oa, unsigned int hostnum)
{
struct pqueue * candidate_list;
struct ospf6_vertex * root, * v, * w;
int i;
int size;
caddr_t lsdesc;
struct ospf6_lsa * lsa;
if(IS_OSPF6_SIBLING_DEBUG_SPF)
{
zlog_debug("Starting spf calculation...");
}
/* initialize */
candidate_list = pqueue_create();
candidate_list->cmp = ospf6_vertex_cmp;
ospf6_spf_table_finish (result_table);
/* Install the calculating router itself as the root of the SPF tree */
/* construct root vertex */
lsa = ospf6_lsdb_lookup (htons (OSPF6_LSTYPE_ROUTER), htonl (0),
router_id, oa->lsdb);
if (lsa == NULL)
{
if(IS_OSPF6_SIBLING_DEBUG_SPF)
{
zlog_debug("Looking for type %d from lsdb %p with router id %d", htons(OSPF6_LSTYPE_ROUTER), oa->lsdb, router_id);
zlog_debug("No router LSAs present, quiting spf calculation");
}
return;
}
root = ospf6_vertex_create (lsa);
root->area = oa;
root->cost = 0;
root->hops = 0;
root->nexthop[0].ifindex = 0; /* loopbak I/F is better ... */
inet_pton (AF_INET6, "::1", &root->nexthop[0].address);
/* Actually insert root to the candidate-list as the only candidate */
pqueue_enqueue (root, candidate_list);
/* Iterate until candidate-list becomes empty */
while (candidate_list->size)
{
/* get closest candidate from priority queue */
v = pqueue_dequeue (candidate_list);
/* installing may result in merging or rejecting of the vertex */
if (ospf6_spf_install (v, result_table, hostnum) < 0)
continue;
/* For each LS description in the just-added vertex V's LSA */
size = (VERTEX_IS_TYPE (ROUTER, v) ?
sizeof (struct ospf6_router_lsdesc) :
sizeof (struct ospf6_network_lsdesc));
for (lsdesc = OSPF6_LSA_HEADER_END (v->lsa->header) + 4;
lsdesc + size <= OSPF6_LSA_END (v->lsa->header); lsdesc += size)
{
lsa = ospf6_lsdesc_lsa (lsdesc, v);
if (lsa == NULL)
continue;
if (! ospf6_lsdesc_backlink (lsa, lsdesc, v))
continue;
w = ospf6_vertex_create (lsa);
w->area = oa;
w->parent = v;
if (VERTEX_IS_TYPE (ROUTER, v))
{
w->cost = v->cost + ROUTER_LSDESC_GET_METRIC (lsdesc);
w->hops = v->hops + (VERTEX_IS_TYPE (NETWORK, w) ? 0 : 1);
}
else /* NETWORK */
{
w->cost = v->cost;
w->hops = v->hops + 1;
}
/* nexthop calculation */
if (w->hops == 0)
w->nexthop[0].ifindex = ROUTER_LSDESC_GET_IFID (lsdesc);
else if (w->hops == 1 && v->hops == 0)
ospf6_nexthop_calc (w, v, lsdesc);
else
{
for (i = 0; ospf6_nexthop_is_set (&v->nexthop[i]) &&
i < OSPF6_MULTI_PATH_LIMIT; i++)
ospf6_nexthop_copy (&w->nexthop[i], &v->nexthop[i]);
}
/* add new candidate to the candidate_list */
if (IS_OSPF6_SIBLING_DEBUG_SPF)
zlog_debug (" New candidate: %s hops %d cost %d",
w->name, w->hops, w->cost);
pqueue_enqueue (w, candidate_list);
}
}
pqueue_delete (candidate_list);
}
