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 ospf_area *oa);
static void rt_sync(struct proto_ospf *po);
static void
fill_ri(orta * orta)
{
orta->type = RTS_DUMMY;
orta->capa = 0;
#define ORTA_ASBR 1
#define ORTA_ABR 2
orta->oa = NULL;
orta->metric1 = LSINFINITY;
orta->metric2 = LSINFINITY;
orta->nh = ipa_from_u32(0);
orta->ifa = NULL;
orta->ar = NULL;
orta->tag = 0;
}
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void
ospf_rt_initort(struct fib_node *fn)
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{
ort *ri = (ort *) fn;
fill_ri(&ri->n);
ri->dest = ORT_UNDEF;
memcpy(&ri->o, &ri->n, sizeof(orta));
}
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/* If new is better return 1 */
static int
ri_better(struct proto_ospf *po, orta * new, orta * old)
{
int newtype = new->type;
int oldtype = old->type;
if (old->type == RTS_DUMMY)
return 1;
if (old->metric1 == LSINFINITY)
return 1;
if (po->rfc1583)
{
if ((newtype == RTS_OSPF) && (new->oa->areaid == 0)) newtype = RTS_OSPF_IA;
if ((oldtype == RTS_OSPF) && (old->oa->areaid == 0)) oldtype = RTS_OSPF_IA;
}
if (new->type < old->type)
return 1;
if (new->metric2 < old->metric2)
{
if (old->metric2 == LSINFINITY)
return 0; /* Old is E1, new is E2 */
return 1; /* Both are E2 */
}
if (new->metric2 > old->metric2)
{
if (new->metric2 == LSINFINITY)
return 1; /* New is E1, old is E2 */
return 0; /* Both are E2 */
}
/*
* E2 metrics are the same. It means that: 1) Paths are E2 with same
* metric 2) Paths are E1.
*/
if (new->metric1 < old->metric1)
return 1;
if (new->metric1 > old->metric1)
return 0;
/* Metric 1 are the same */
if (new->oa->areaid > old->oa->areaid) return 1; /* Larger AREAID is preffered */
return 0; /* Old is shorter or same */
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}
static void
ri_install(struct proto_ospf *po, ip_addr prefix, int pxlen, int dest,
orta * new)
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{
ort *old = (ort *) fib_get(&po->rtf[dest], &prefix, pxlen);
if (ri_better(po, new, &old->n))
{
memcpy(&old->n, new, sizeof(orta));
}
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}
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/**
* ospf_rt_spf - calculate internal routes
* @po: OSPF protocol
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*
* 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.
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* 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().
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*/
static void
ospf_rt_spfa(struct ospf_area *oa)
{
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u32 i, *rts;
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struct ospf_lsa_rt *rt;
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struct ospf_lsa_rt_link *rtl, *rr;
struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
struct ospf_lsa_net *ln;
orta nf;
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if (oa->rt == NULL)
return;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for area %I",
oa->areaid);
if (oa->rt->dist != LSINFINITY)
ospf_age(oa);
init_list(&oa->cand); /* Empty list of candidates */
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oa->trcap = 0;
DBG("LSA db prepared, adding me into candidate list.\n");
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oa->rt->dist = 0;
oa->rt->color = CANDIDATE;
add_head(&oa->cand, &oa->rt->cn);
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DBG("RT LSA: rt: %I, id: %I, type: %u\n", oa->rt->lsa.rt,
oa->rt->lsa.id, oa->rt->lsa.type);
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while (!EMPTY_LIST(oa->cand))
{
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struct top_hash_entry *act, *tmp;
node *n;
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n = HEAD(oa->cand);
act = SKIP_BACK(struct top_hash_entry, cn, n);
rem_node(n);
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DBG("Working on LSA: rt: %I, id: %I, type: %u\n", act->lsa.rt,
act->lsa.id, act->lsa.type);
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act->color = INSPF;
switch (act->lsa.type)
{
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case LSA_T_RT:
rt = (struct ospf_lsa_rt *) act->lsa_body;
if (rt->veb.bit.v)
oa->trcap = 1;
if (rt->veb.bit.b || rt->veb.bit.e)
{
nf.type = RTS_OSPF;
nf.capa = 0;
if (rt->veb.bit.b) nf.capa |= ORTA_ABR;
if (rt->veb.bit.e) nf.capa |= ORTA_ASBR;
nf.metric1 = act->dist;
nf.metric2 = LSINFINITY;
nf.oa = oa;
nf.ar = act;
nf.nh = act->nh;
nf.ifa = act->nhi;
ri_install(po, ipa_from_u32(act->lsa.id), 32, ORT_ROUTER, &nf);
}
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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)
{
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case LSART_STUB:
/*
* This violates rfc2328! but I hope
* it's also correct.
*/
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DBG("\n");
if (act == oa->rt)
continue;
if (!act->nhi)
continue;
nf.type = RTS_OSPF;
nf.capa = 0;
nf.metric1 = act->dist + rtl->metric;
nf.metric2 = LSINFINITY;
nf.oa = oa;
nf.ar = act;
nf.nh = act->nh;
nf.ifa = act->nhi;
ri_install(po, ipa_from_u32(rtl->id),
ipa_mklen(ipa_from_u32(rtl->data)), ORT_NET, &nf);
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break;
case LSART_VLNK: /* FIXME !!!!!!!! */
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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;
}
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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;
nf.type = RTS_OSPF;
nf.capa = 0;
nf.metric1 = act->dist;
nf.metric2 = LSINFINITY;
nf.oa = oa;
nf.ar = act;
nf.nh = act->nh;
nf.ifa = act->nhi;
ri_install(po, ipa_and(ipa_from_u32(act->lsa.id), ln->netmask),
ipa_mklen(ln->netmask), ORT_NET, &nf);
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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;
}
}
}
void
ospf_rt_spf(struct proto_ospf *po)
{
struct proto *p = &po->proto;
struct ospf_area *oa;
int i;
ort *ri;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation");
/* Invalidate old routing table */
for (i = 0; i < 2; i++)
FIB_WALK(&po->rtf[i], nftmp)
{
ri = (ort *) nftmp;
memcpy(&ri->o, &ri->n, sizeof(orta)); /* Backup old data */
fill_ri(&ri->n);
}
FIB_WALK_END;
WALK_LIST(oa, po->area_list)
{
ospf_rt_spfa(oa);
}
if (po->areano > 1)
{
//ospf_rt_sum(oa);
}
else
{
WALK_LIST(oa, po->area_list)
{
//if (oa->id == 0) ospf_rt_sum(oa);
}
WALK_LIST(oa, po->area_list)
{
//if (oa->trcap == 1) ospf_rt_sum(oa);
}
}
WALK_LIST(oa, po->area_list)
{
if (!oa->stub)
{
ospf_ext_spfa(oa);
break;
}
}
rt_sync(po);
}
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/**
* 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 ospf_area *oa)
{
struct proto_ospf *po = oa->po;
ort *nf1, *nf2;
orta nfa;
struct top_hash_entry *en;
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struct proto *p = &po->proto;
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struct ospf_lsa_ext *le;
struct ospf_lsa_ext_tos *lt;
int mlen;
ip_addr ip, nh, rtid;
struct iface *nhi = NULL;
int met1, met2;
neighbor *nn;
struct ospf_lsa_rt *rt;
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OSPF_TRACE(D_EVENTS, "Starting routing table calculation for ext routes");
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WALK_SLIST(en, oa->lsal)
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{
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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;
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le = en->lsa_body;
lt = (struct ospf_lsa_ext_tos *) (le + 1);
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DBG("%s: Working on LSA. ID: %I, RT: %I, Type: %u, Mask %I\n",
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p->name, en->lsa.id, en->lsa.rt, en->lsa.type, le->netmask);
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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",
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p->name, en->lsa.id, en->lsa.rt, en->lsa.type, le->netmask);
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continue;
}
nhi = NULL;
nh = IPA_NONE;
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met1 = LSINFINITY;
met2 = LSINFINITY;
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rtid = ipa_from_u32(en->lsa.rt);
if (!(nf1 = fib_find(&po->rtf[ORT_ROUTER], &rtid, 32)))
continue; /* No AS boundary router found */
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if (nf1->n.metric1 == LSINFINITY)
continue; /* distance is INF */
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if (!(nf1->n.capa & ORTA_ASBR))
continue; /* It is not ASBR */
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if (ipa_compare(lt->fwaddr, ipa_from_u32(0)) == 0)
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{
if (lt->etos > 0)
{ /* FW address == 0 */
met1 = nf1->n.metric1;
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met2 = lt->metric;
}
else
{
met1 = nf1->n.metric1 + lt->metric;
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met2 = LSINFINITY;
}
nh = nf1->n.nh;
nhi = nf1->n.ifa;
}
else
{ /* FW address !=0 */
if (!(nf2 = fib_route(&po->rtf[ORT_NET], lt->fwaddr, 32)))
{
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DBG("Cannot find network route (GW=%I)\n", lt->fwaddr);
continue;
}
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if (lt->etos > 0)
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{
met1 = nf2->n.metric1;
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met2 = lt->metric;
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}
else
{
met1 = nf2->n.metric1 + lt->metric;
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met2 = LSINFINITY;
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}
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if ((nn = neigh_find(p, &lt->fwaddr, 0)) != NULL)
{
nh = lt->fwaddr;
nhi = nn->iface;
}
else
{
nh = nf2->n.nh;
nhi = nf2->n.ifa;
}
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}
nfa.type = RTS_OSPF_EXT;
nfa.capa = 0;
nfa.metric1 = met1;
nfa.metric2 = met2;
nfa.oa = oa;
nfa.ar = nf1->n.ar;
nfa.nh = nh;
nfa.ifa = nhi;
nfa.tag = lt->tag;
ri_install(po, ip, mlen, ORT_NET, &nfa);
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}
}
/* Add LSA into list of candidates in Dijkstra's algorithm */
static void
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add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
u16 dist, struct ospf_area *oa)
{
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node *prev, *n;
int added = 0;
struct top_hash_entry *act;
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if (en == NULL)
return;
if (en->lsa.age == LSA_MAXAGE)
return;
/* FIXME Does it have link back? Test it! */
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if (en->color == INSPF)
return;
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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
*/
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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);
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if (!en->nhi)
return; /* We cannot find next hop, ignore it */
if (en->color == CANDIDATE)
{ /* We found a shorter path */
rem_node(&en->cn);
}
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en->dist = dist;
en->color = CANDIDATE;
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prev = NULL;
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if (EMPTY_LIST(*l))
{
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add_head(l, &en->cn);
}
else
{
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WALK_LIST(n, *l)
{
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act = SKIP_BACK(struct top_hash_entry, cn, n);
if ((act->dist > dist) ||
((act->dist == dist) && (act->lsa.type == LSA_T_NET)))
{
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if (prev == NULL)
add_head(l, &en->cn);
else
insert_node(&en->cn, prev);
added = 1;
break;
}
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prev = n;
}
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if (!added)
{
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add_tail(l, &en->cn);
}
}
/* FIXME Some VLINK stuff should be here */
}
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static void
calc_next_hop(struct top_hash_entry *en, struct top_hash_entry *par,
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struct ospf_area *oa)
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{
struct ospf_neighbor *neigh;
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struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
struct ospf_iface *ifa;
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u32 myrid = p->cf->global->router_id;
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DBG(" Next hop called.\n");
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if (ipa_equal(par->nh, IPA_NONE))
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{
neighbor *nn;
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DBG(" Next hop calculating for id: %I rt: %I type: %u\n",
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en->lsa.id, en->lsa.rt, en->lsa.type);
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if (par == oa->rt)
{
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if (en->lsa.type == LSA_T_NET)
{
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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)
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{
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;
}
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}
else
{
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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 */
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return;
}
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}
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if (par->lsa.type == LSA_T_NET)
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{
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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 */
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return;
}
else
{ /* Parent is some RT neighbor */
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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;
}
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}
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en->nh = par->nh;
en->nhi = par->nhi;
DBG(" Next hop calculated: %I.\n", en->nh);
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}
static void
rt_sync(struct proto_ospf *po)
{
struct proto *p = &po->proto;
struct fib_iterator fit;
struct fib *fib = &po->rtf[ORT_NET];
ort *nf;
DBG("Now syncing my rt table with nest's\n");
FIB_ITERATE_INIT(&fit, fib);
again:
FIB_ITERATE_START(fib, &fit, nftmp)
{
nf = (ort *) nftmp;
if (nf->n.metric1 == 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(fib, nftmp);
goto again;
}
else if (memcmp(&nf->n, &nf->o, sizeof(orta)))
{ /* Some difference */
net *ne;
rta a0;
rte *e;
bzero(&a0, sizeof(a0));
a0.proto = p;
a0.source = nf->n.type;
a0.scope = SCOPE_UNIVERSE;
a0.cast = RTC_UNICAST;
a0.dest = RTD_ROUTER;
a0.flags = 0;
a0.aflags = 0;
a0.iface = nf->n.ifa;
a0.gw = nf->n.nh;
ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
e = rte_get_temp(&a0);
e->u.ospf.metric1 = nf->n.metric1;
e->u.ospf.metric2 = nf->n.metric2;
e->u.ospf.tag = nf->n.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);
}
}
FIB_ITERATE_END(nftmp);
}