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bird/proto/ospf/rt.c

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/*
* BIRD -- OSPF
*
* (c) 2000--2004 Ondrej Filip <feela@network.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "ospf.h"
static void add_cand(list * l, struct top_hash_entry *en,
struct top_hash_entry *par, u16 dist,
struct ospf_area *oa);
static void calc_next_hop(struct top_hash_entry *en,
struct top_hash_entry *par, struct ospf_area *oa);
static void ospf_ext_spfa(struct proto_ospf *po);
void
init_infib(struct fib_node *fn)
{
struct infib *f = (struct infib *) fn;
f->metric = LSINFINITY;
f->oldmetric = LSINFINITY;
f->en = NULL;
f->olden = NULL;
}
void
init_efib(struct fib_node *fn)
{
struct extfib *f = (struct extfib *) fn;
f->metric = LSINFINITY;
f->metric2 = LSINFINITY;
f->nh = ipa_from_u32(0);
f->nhi = NULL;
f->oldmetric = LSINFINITY;
f->oldmetric2 = LSINFINITY;
f->oldnh = ipa_from_u32(0);
}
/**
* ospf_rt_spf - calculate internal routes
* @po: OSPF protocol
*
* Calculation of internal paths in an area is described in 16.1 of RFC 2328.
* It's based on Dijkstra's shortest path tree algorithms.
* RFC recommends to add ASBR routers into routing table. I don't do this
* and latter parts of routing table calculation look directly into LSA
* Database. This function is invoked from ospf_disp().
*/
void
ospf_rt_spfa(struct ospf_area *oa)
{
u32 i, *rts;
struct ospf_lsa_rt *rt;
struct ospf_lsa_rt_link *rtl, *rr;
struct fib *in = &oa->infib;
struct infib *nf;
struct fib_iterator fit;
struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
ip_addr ip;
struct ospf_lsa_net *ln;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for area %I",
oa->areaid);
if (oa->rt == NULL)
return;
if (oa->rt->dist != LSINFINITY)
ospf_age(oa);
FIB_WALK(in, nftmp)
{
nf = (struct infib *) nftmp;
nf->metric = LSINFINITY;
nf->en = NULL;
}
FIB_WALK_END;
init_list(&oa->cand); /* Empty list of candidates */
oa->trcap = 0;
DBG("LSA db prepared, adding me into candidate list.\n");
oa->rt->dist = 0;
oa->rt->color = CANDIDATE;
add_head(&oa->cand, &oa->rt->cn);
DBG("RT LSA: rt: %I, id: %I, type: %u\n", oa->rt->lsa.rt,
oa->rt->lsa.id, oa->rt->lsa.type);
while (!EMPTY_LIST(oa->cand))
{
struct top_hash_entry *act, *tmp;
node *n;
u16 met;
n = HEAD(oa->cand);
act = SKIP_BACK(struct top_hash_entry, cn, n);
rem_node(n);
DBG("Working on LSA: rt: %I, id: %I, type: %u\n", act->lsa.rt,
act->lsa.id, act->lsa.type);
act->color = INSPF;
switch (act->lsa.type)
{
case LSA_T_RT:
rt = (struct ospf_lsa_rt *) act->lsa_body;
if (rt->veb.bit.v)
oa->trcap = 1;
rr = (struct ospf_lsa_rt_link *) (rt + 1);
DBG(" Number of links: %u\n", rt->links);
for (i = 0; i < rt->links; i++)
{
tmp = NULL;
rtl = (rr + i);
DBG(" Working on link: %I (type: %u) ", rtl->id, rtl->type);
switch (rtl->type)
{
case LSART_STUB:
/* This violates rfc2328! but I hope it's also correct. */
DBG("\n");
ip = ipa_from_u32(rtl->id);
nf = fib_get(in, &ip, ipa_mklen(ipa_from_u32(rtl->data)));
if (nf->metric > (met = act->dist + rtl->metric))
{
DBG(" Adding stub route....\n");
if (oa->rt == act)
break;
if (act->nhi == NULL)
break;
nf->metric = met;
nf->en = act;
DBG(" Adding stub route: %I\n", ip);
DBG(" Next hop=%I\n", nf->en->nh);
}
else
DBG(" NOT adding stub route: %I\n", ip);
break;
case LSART_VLNK:
DBG("Ignoring\n");
continue;
break;
case LSART_NET:
tmp = ospf_hash_find(oa->gr, rtl->id, rtl->id, LSA_T_NET);
if (tmp == NULL)
DBG("Not found!\n");
else
DBG("Found. :-)\n");
break;
case LSART_PTP:
tmp = ospf_hash_find(oa->gr, rtl->id, rtl->id, LSA_T_RT);
DBG("PTP found.\n");
break;
default:
log("Unknown link type in router lsa.");
break;
}
if (tmp)
DBG("Going to add cand, Mydist: %u, Req: %u\n",
tmp->dist, act->dist + rtl->metric);
add_cand(&oa->cand, tmp, act, act->dist + rtl->metric, oa);
}
break;
case LSA_T_NET:
ln = act->lsa_body;
ip = ipa_and(ipa_from_u32(act->lsa.id), ln->netmask);
nf = fib_get(in, &ip, ipa_mklen(ln->netmask));
if (nf->metric > act->dist)
{
nf->metric = act->dist;
nf->en = act;
DBG(" Adding into routing table\n");
}
rts = (u32 *) (ln + 1);
for (i = 0; i < (act->lsa.length - sizeof(struct ospf_lsa_header) -
sizeof(struct ospf_lsa_net)) / sizeof(u32); i++)
{
DBG(" Working on router %I ", *(rts + i));
tmp = ospf_hash_find(oa->gr, *(rts + i), *(rts + i), LSA_T_RT);
if (tmp != NULL)
DBG("Found :-)\n");
else
DBG("Not found!\n");
add_cand(&oa->cand, tmp, act, act->dist, oa);
}
break;
}
}
/* Now sync our fib with nest's */
DBG("Now syncing my rt table with nest's\n");
FIB_ITERATE_INIT(&fit, in);
again:
FIB_ITERATE_START(in, &fit, nftmp)
{
nf = (struct infib *) nftmp;
if (nf->metric == LSINFINITY)
{
net *ne;
struct top_hash_entry *en = nf->en;
ln = en->lsa_body;
ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
if ((en != NULL) && (en->nhi != NULL))
DBG("Deleting rt entry %I\n (P: %x, GW: %I, Iface: %s)\n",
nf->fn.prefix, en, en->nh, en->nhi->name);
rte_update(p->table, ne, p, NULL);
/* Now delete my fib */
FIB_ITERATE_PUT(&fit, nftmp);
fib_delete(in, nftmp);
goto again;
}
else
{
/* Update routing table */
if (ipa_equal(nf->en->nh, ipa_from_u32(0)))
{
struct top_hash_entry *en = nf->en;
struct ospf_neighbor *neigh;
neighbor *nn;
if ((neigh = find_neigh_noifa(po, en->lsa.rt)) == NULL)
{
goto skip;
}
nn = neigh_find(p, &neigh->ip, 0);
DBG(" Next hop calculated: %I\n", nn->addr);
en->nh = nn->addr;
en->nhi = nn->iface;
}
if ((nf->en != nf->olden) || (nf->metric != nf->oldmetric))
{
net *ne;
rta a0;
rte *e;
struct top_hash_entry *en = nf->en;
ln = en->lsa_body;
bzero(&a0, sizeof(a0));
a0.proto = p;
a0.source = RTS_OSPF;
a0.scope = SCOPE_UNIVERSE;
a0.cast = RTC_UNICAST;
if (ipa_to_u32(en->nh) == 0)
a0.dest = RTD_DEVICE;
else
a0.dest = RTD_ROUTER;
a0.flags = 0;
a0.aflags = 0;
a0.iface = en->nhi;
a0.gw = en->nh;
ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
e = rte_get_temp(&a0);
e->u.ospf.metric1 = nf->metric;
e->u.ospf.metric2 = LSINFINITY;
e->u.ospf.tag = 0;
e->pflags = 0;
e->net = ne;
e->pref = p->preference;
DBG("Modifying rt entry %I\n (GW: %I, Iface: %s)\n",
nf->fn.prefix, en->nh, en->nhi->name);
rte_update(p->table, ne, p, e);
nf->olden = nf->en;
nf->oldmetric = nf->metric;
}
}
}
skip:
FIB_ITERATE_END(nftmp);
ospf_ext_spfa(po);
}
void
ospf_rt_spf(struct proto_ospf *po)
{
struct ospf_area *oa;
WALK_LIST(oa, po->area_list)
{
ospf_rt_spfa(oa);
}
}
/**
* ospf_ext_spfa - calculate external paths
* @po: protocol
*
* After routing table for any area is calculated, calculation of external
* path is invoked. This process is described in 16.6 of RFC 2328.
* Inter- and Intra-area paths are always prefered over externals.
*/
static void
ospf_ext_spfa(struct proto_ospf *po) /* FIXME looking into inter-area */
{
struct top_hash_entry *en, *etmp, *absr;
struct fib *ef = &po->efib;
struct extfib *nf;
struct infib *inf;
struct fib_iterator fit;
struct ospf_area *oa = NULL, *atmp, *absroa;
struct proto *p = &po->proto;
struct ospf_lsa_ext *le;
struct ospf_lsa_ext_tos *lt;
int mlen;
ip_addr ip, nnh;
struct iface *nnhi = NULL;
u16 met, met2;
u32 tag;
neighbor *nn;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for ext routes");
FIB_WALK(ef, nftmp)
{
nf = (struct extfib *) nftmp;
nf->metric = LSINFINITY;
nf->metric2 = LSINFINITY;
}
FIB_WALK_END;
WALK_LIST(oa, po->area_list)
{
if (!oa->stub)
break;
}
if (oa == NULL)
return;
WALK_SLIST(en, oa->lsal)
{
if (en->lsa.type != LSA_T_EXT)
continue;
if (en->lsa.age == LSA_MAXAGE)
continue;
if (en->lsa.rt == p->cf->global->router_id)
continue;
le = en->lsa_body;
lt = (struct ospf_lsa_ext_tos *) (le + 1);
DBG("%s: Working on LSA. ID: %I, RT: %I, Type: %u, Mask %I\n",
p->name, en->lsa.id, en->lsa.rt, en->lsa.type, le->netmask);
if (lt->metric == LSINFINITY)
continue;
ip = ipa_and(ipa_from_u32(en->lsa.id), le->netmask);
mlen = ipa_mklen(le->netmask);
if ((mlen < 0) || (mlen > 32))
{
log("%s: Invalid mask in LSA. ID: %I, RT: %I, Type: %u, Mask %I",
p->name, en->lsa.id, en->lsa.rt, en->lsa.type, le->netmask);
continue;
}
nf = NULL;
WALK_LIST(atmp, po->area_list)
{
if ((nf = fib_find(&atmp->infib, &ip, mlen)) != NULL)
break;
}
if (nf != NULL)
continue; /* Some intra area path exists */
absr = NULL;
absroa = NULL;
nnhi = NULL;
nnh = IPA_NONE;
met = 0;
met2 = 0;
tag = 0;
WALK_LIST(atmp, po->area_list) /*
* Find shortest path
* to advertising router
*/
{
if ((etmp =
ospf_hash_find(atmp->gr, en->lsa.rt, en->lsa.rt,
LSA_T_RT)) != NULL)
{
if ((absr == NULL) || (absr->dist > etmp->dist) ||
((etmp->dist == absr->dist) && (absroa->areaid < atmp->areaid)))
{
absr = etmp;
absroa = atmp;
break;
}
}
}
if ((absr == NULL) || (absr->dist == LSINFINITY) ||
(((struct ospf_lsa_rt *) (absr->lsa_body))->veb.bit.e == 0))
{
DBG("ASBR is null or its dist=INF\n");
continue;
}
if (ipa_compare(lt->fwaddr, ipa_from_u32(0)) == 0)
{
if (lt->etos > 0) /* FW address == 0 */
{
met = absr->dist;
met2 = lt->metric;
}
else
{
met = absr->dist + lt->metric;
met2 = LSINFINITY;
}
tag = lt->tag;
}
else /* FW address !=0 */
{
inf = NULL;
WALK_LIST(atmp, po->area_list)
{
if ((inf = fib_route(&atmp->infib, lt->fwaddr, 32)) != NULL)
{
break;
}
}
if (inf == NULL)
{
DBG("Cannot find network route (GW=%I)\n", lt->fwaddr);
continue;
}
if (lt->etos > 0)
{
met = inf->metric;
met2 = lt->metric;
}
else
{
met = inf->metric + lt->metric;
met2 = LSINFINITY;
}
tag = lt->tag;
if ((nn = neigh_find(p, &lt->fwaddr, 0)) != NULL)
{
nnh = lt->fwaddr;
nnhi = nn->iface;
}
else
{
nnh = inf->en->nh;
nnhi = inf->en->nhi;
}
}
nf = fib_get(ef, &ip, mlen);
if ((nf->metric == LSINFINITY) || /* nf is new */
((met < nf->metric) && (nf->metric2 == met2)) || /* both E1 or E2
* with same metric */
((met2 < nf->metric2) && (nf->metric2 != LSINFINITY)) || /* E2 smaller and
* 1st is not E1 */
((nf->metric2 != LSINFINITY) && (met2 == LSINFINITY))) /* 2nd is E1 and
* 1st is E2 */
{
if (nf->metric != LSINFINITY)
OSPF_TRACE(D_EVENTS,
"Rewriting %I/%d met=%d, met2=%d, nmet=%d, nmet2=%d",
ip, mlen, nf->metric, nf->metric2, met, met2);
nf->metric = met;
nf->metric2 = met2;
nf->tag = tag;
if (nnhi != NULL)
{
nf->nh = nnh;
nf->nhi = nnhi;
}
else
{
if (ipa_compare(absr->nh, ipa_from_u32(0)) == 0)
{
struct ospf_neighbor *neigh;
if ((neigh = find_neigh_noifa(po, absr->lsa.rt)) == NULL)
{
DBG("Cannot find neighbor\n");
nf->metric = LSINFINITY; /* delete this route */
continue;
}
nn = neigh_find(p, &neigh->ip, 0);
DBG(" Next hop calculated: %I\n", nn->addr);
nf->nh = nn->addr;
nf->nhi = nn->iface;
}
else
{
nf->nh = absr->nh;
nf->nhi = absr->nhi;
}
}
}
}
DBG("Now syncing my rt table with nest's\n");
FIB_ITERATE_INIT(&fit, ef);
noch:
FIB_ITERATE_START(ef, &fit, nftmp)
{
nf = (struct extfib *) nftmp;
if (nf->metric == LSINFINITY)
{
net *ne;
ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
DBG("Deleting rt entry %I\n (IP: %I, GW: %I)\n",
nf->fn.prefix, ip, nf->nh);
rte_update(p->table, ne, p, NULL);
/* Now delete my fib */
FIB_ITERATE_PUT(&fit, nftmp);
fib_delete(ef, nftmp);
goto noch;
}
else
if ((nf->metric != nf->oldmetric) || (nf->metric2 != nf->oldmetric2) ||
(!ipa_equal(nf->nh, nf->oldnh)) || (nf->tag != nf->oldtag))
{
net *ne;
rta a0;
rte *e;
bzero(&a0, sizeof(a0));
a0.proto = p;
a0.source = RTS_OSPF_EXT;
a0.scope = SCOPE_UNIVERSE;
a0.cast = RTC_UNICAST;
a0.dest = RTD_ROUTER;
a0.flags = 0;
a0.aflags = 0;
a0.iface = nf->nhi;
a0.gw = nf->nh;
ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
e = rte_get_temp(&a0);
e->u.ospf.metric1 = nf->metric;
e->u.ospf.metric2 = nf->metric2;
e->u.ospf.tag = nf->tag;
e->pflags = 0;
e->net = ne;
e->pref = p->preference;
DBG("Modifying rt entry %I\n (IP: %I, GW: %I)\n",
nf->fn.prefix, ip, nf->nh);
rte_update(p->table, ne, p, e);
nf->oldmetric = nf->metric;
nf->oldmetric2 = nf->metric2;
nf->oldnh = nf->nh;
nf->oldtag = nf->tag;
}
}
FIB_ITERATE_END(nftmp);
}
/* Add LSA into list of candidates in Dijkstra's algorithm */
static void
add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
u16 dist, struct ospf_area *oa)
{
node *prev, *n;
int added = 0;
struct top_hash_entry *act;
if (en == NULL)
return;
if (en->lsa.age == LSA_MAXAGE)
return;
/* FIXME Does it have link back? Test it! */
if (en->color == INSPF)
return;
if (dist >= en->dist)
return;
/*
* FIXME The line above is not a bug, but we don't support
* multiple next hops. I'll start as soon as nest will
*/
DBG(" Adding candidate: rt: %I, id: %I, type: %u\n", en->lsa.rt,
en->lsa.id, en->lsa.type);
en->nhi = NULL;
en->nh = IPA_NONE;
calc_next_hop(en, par, oa);
if (!en->nhi)
return; /* We cannot find next hop, ignore it */
if (en->color == CANDIDATE) /* We found a shorter path */
{
rem_node(&en->cn);
}
en->dist = dist;
en->color = CANDIDATE;
prev = NULL;
if (EMPTY_LIST(*l))
{
add_head(l, &en->cn);
}
else
{
WALK_LIST(n, *l)
{
act = SKIP_BACK(struct top_hash_entry, cn, n);
if ((act->dist > dist) ||
((act->dist == dist) && (act->lsa.type == LSA_T_NET)))
{
if (prev == NULL)
add_head(l, &en->cn);
else
insert_node(&en->cn, prev);
added = 1;
break;
}
prev = n;
}
if (!added)
{
add_tail(l, &en->cn);
}
}
/* FIXME Some VLINK stuff should be here */
}
static void
calc_next_hop(struct top_hash_entry *en, struct top_hash_entry *par,
struct ospf_area *oa)
{
struct ospf_neighbor *neigh;
struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
struct ospf_iface *ifa;
u32 myrid = p->cf->global->router_id;
DBG(" Next hop called.\n");
if (ipa_equal(par->nh, IPA_NONE))
{
neighbor *nn;
DBG(" Next hop calculating for id: %I rt: %I type: %u\n",
en->lsa.id, en->lsa.rt, en->lsa.type);
if (par == oa->rt)
{
if (en->lsa.type == LSA_T_NET)
{
if (en->lsa.rt == myrid)
{
WALK_LIST(ifa, po->iface_list)
if (ipa_compare
(ifa->iface->addr->ip, ipa_from_u32(en->lsa.id)) == 0)
{
en->nhi = ifa->iface;
return;
}
log(L_ERR "I didn't find interface for my self originated LSA!\n");
/* This could sometimes happen */
return;
}
else
{
ip_addr ip = ipa_from_u32(en->lsa.id);
nn = neigh_find(p, &ip, 0);
if (nn)
en->nhi = nn->iface;
return;
}
}
else
{
if ((neigh = find_neigh_noifa(po, en->lsa.rt)) == NULL)
return;
en->nhi = neigh->ifa->iface;
en->nh = neigh->ip; /* Yes, neighbor is it's own next hop */
return;
}
}
if (par->lsa.type == LSA_T_NET)
{
if (en->lsa.type == LSA_T_NET)
bug("Parent for net is net?");
if ((en->nhi = par->nhi) == NULL)
bug("Did not find next hop interface for INSPF lsa!");
if ((neigh = find_neigh_noifa(po, en->lsa.rt)) == NULL)
return;
en->nhi = neigh->ifa->iface;
en->nh = neigh->ip; /* Yes, neighbor is it's own next hop */
return;
}
else /* Parent is some RT neighbor */
{
log(L_ERR "Router's parent has no next hop. (EN=%I, PAR=%I)",
en->lsa.id, par->lsa.id);
/* I hoped this would never happen */
return;
}
}
en->nh = par->nh;
en->nhi = par->nhi;
DBG(" Next hop calculated: %I.\n", en->nh);
}
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