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labs-bird/proto/ospf/rt.c
Ondrej Filip 9b13345889 Hotfix for router's parent without nexthop. 
It will probably work perfect, but I need to eliminate such situation.
2004-06-02 09:14:03 +00:00

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/*
* BIRD -- OSPF
*
* (c) 2000 Ondrej Filip <feela@network.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "ospf.h"
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_spfa - calculate internal routes
* @oa: OSPF area
*
* 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 area_disp().
*/
void
ospf_rt_spfa(struct ospf_area *oa)
{
struct top_hash_entry *en;
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;
int age=0,flush=0;
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;
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);
}
/**
* 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.
*/
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;
struct ospf_lsa_rt *rt;
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;
}
}
let:
FIB_ITERATE_END(nftmp);
}
/* Add LSA into list of candidates in Dijkstra's algorithm */
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 flag=0,added=0;
struct top_hash_entry *act;
struct proto *p=&oa->po->proto;
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 */
}
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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