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bird/proto/ospf/rt.c
Ondrej Zajicek 54818e9beb A minor bugfix in OSPF ext-LSA processing.
2010-05-03 00:10:48 +02:00

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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, u32 dist,
struct ospf_area *oa);
static int calc_next_hop(struct ospf_area *oa,
struct top_hash_entry *en,
struct top_hash_entry *par);
static void rt_sync(struct proto_ospf *po);
/* In ospf_area->rtr we store paths to routers, but we use RID (and not IP address)
as index, so we need to encapsulate RID to IP address */
#ifdef OSPFv2
#define ipa_from_rid(x) _MI(x)
#else /* OSPFv3 */
#define ipa_from_rid(x) _MI(0,0,0,x)
#endif
static inline void reset_ri(orta * orta)
{
bzero(orta, sizeof(orta));
}
void
ospf_rt_initort(struct fib_node *fn)
{
ort *ri = (ort *) fn;
reset_ri(&ri->n);
reset_ri(&ri->o);
ri->fn.x0 = 0;
}
/* If new is better return 1 */
static int
ri_better(struct proto_ospf *po, orta *new, orta *old)
{
if (old->type == RTS_DUMMY)
return 1;
if (new->type < old->type)
return 1;
if (new->type > old->type)
return 0;
if (new->metric1 < old->metric1)
return 1;
if (new->metric1 > old->metric1)
return 0;
return 0;
}
/* Whether the ASBR or the forward address destination is preferred
in AS external route selection according to 16.4.1. */
static inline int
epath_preferred(orta *ep)
{
return (ep->type == RTS_OSPF) && (ep->oa->areaid != 0);
}
/* 16.4. (3), return 1 if new is better */
static int
ri_better_asbr(struct proto_ospf *po, orta *new, orta *old)
{
if (old->type == RTS_DUMMY)
return 1;
if (!po->rfc1583)
{
int new_pref = epath_preferred(new);
int old_pref = epath_preferred(old);
if (new_pref > old_pref)
return 1;
if (new_pref < old_pref)
return 0;
}
if (new->metric1 < old->metric1)
return 1;
if (new->metric1 > old->metric1)
return 0;
/* Larger area ID is preferred */
if (new->oa->areaid > old->oa->areaid)
return 1;
return 0;
}
/* 16.4. (6), return 1 if new is better */
static int
ri_better_ext(struct proto_ospf *po, orta *new, orta *old)
{
if (old->type == RTS_DUMMY)
return 1;
/* 16.4. (6a) */
if (new->type < old->type)
return 1;
if (new->type > old->type)
return 0;
/* 16.4. (6b), same type */
if (new->type == RTS_OSPF_EXT2)
{
if (new->metric2 < old->metric2)
return 1;
if (new->metric2 > old->metric2)
return 0;
}
/* 16.4. (6c) */
if (!po->rfc1583)
{
u32 new_pref = new->options & ORTA_PREF;
u32 old_pref = old->options & ORTA_PREF;
if (new_pref > old_pref)
return 1;
if (new_pref < old_pref)
return 0;
}
/* 16.4. (6d) */
if (new->metric1 < old->metric1)
return 1;
if (new->metric1 > old->metric1)
return 0;
return 0;
}
static inline void
ri_install_net(struct proto_ospf *po, ip_addr prefix, int pxlen, orta *new)
{
ort *old = (ort *) fib_get(&po->rtf, &prefix, pxlen);
if (ri_better(po, new, &old->n))
memcpy(&old->n, new, sizeof(orta));
}
static inline void
ri_install_rt(struct ospf_area *oa, u32 rid, orta *new)
{
ip_addr addr = ipa_from_rid(rid);
ort *old = (ort *) fib_get(&oa->rtr, &addr, MAX_PREFIX_LENGTH);
if (ri_better(oa->po, new, &old->n))
memcpy(&old->n, new, sizeof(orta));
}
static inline void
ri_install_asbr(struct proto_ospf *po, ip_addr *addr, orta *new)
{
ort *old = (ort *) fib_get(&po->backbone->rtr, addr, MAX_PREFIX_LENGTH);
if (ri_better_asbr(po, new, &old->n))
memcpy(&old->n, new, sizeof(orta));
}
static inline void
ri_install_ext(struct proto_ospf *po, ip_addr prefix, int pxlen, orta *new)
{
ort *old = (ort *) fib_get(&po->rtf, &prefix, pxlen);
if (ri_better_ext(po, new, &old->n))
memcpy(&old->n, new, sizeof(orta));
}
#ifdef OSPFv2
static struct ospf_iface *
find_stub_src(struct ospf_area *oa, ip_addr px, int pxlen)
{
struct ospf_iface *iff;
WALK_LIST(iff, oa->po->iface_list)
if ((iff->type != OSPF_IT_VLINK) &&
(iff->oa == oa) &&
ipa_equal(iff->addr->prefix, px) &&
(iff->addr->pxlen == pxlen))
return iff;
return NULL;
}
#else /* OSPFv3 */
static struct ospf_iface *
find_stub_src(struct ospf_area *oa, ip_addr px, int pxlen)
{
struct ospf_iface *iff;
struct ifa *a;
WALK_LIST(iff, oa->po->iface_list)
if ((iff->type != OSPF_IT_VLINK) &&
(iff->oa == oa))
WALK_LIST(a, iff->iface->addrs)
if (ipa_equal(a->prefix, px) &&
(a->pxlen == pxlen) &&
!(a->flags & IA_SECONDARY))
return iff;
return NULL;
}
#endif
static void
add_network(struct ospf_area *oa, ip_addr px, int pxlen, int metric, struct top_hash_entry *en)
{
orta nf = {
.type = RTS_OSPF,
.options = 0,
.metric1 = metric,
.metric2 = LSINFINITY,
.tag = 0,
.rid = en->lsa.rt,
.oa = oa,
.ifa = en->nhi,
.nh = en->nh
};
if (en == oa->rt)
{
/*
* Local stub networks does not have proper iface in en->nhi
* (because they all have common top_hash_entry en).
* We have to find iface responsible for that stub network.
* Some stubnets does not have any iface. Ignore them.
*/
nf.ifa = find_stub_src(oa, px, pxlen);
nf.nh = IPA_NONE;
if (!nf.ifa)
return;
}
ri_install_net(oa->po, px, pxlen, &nf);
}
#ifdef OSPFv3
static void
process_prefixes(struct ospf_area *oa)
{
struct proto_ospf *po = oa->po;
// struct proto *p = &po->proto;
struct top_hash_entry *en, *src;
struct ospf_lsa_prefix *px;
ip_addr pxa;
int pxlen;
u8 pxopts;
u16 metric;
u32 *buf;
int i;
WALK_SLIST(en, po->lsal)
{
if (en->lsa.type != LSA_T_PREFIX)
continue;
if (en->domain != oa->areaid)
continue;
if (en->lsa.age == LSA_MAXAGE)
continue;
px = en->lsa_body;
/* For router prefix-LSA, we would like to find the first router-LSA */
if (px->ref_type == LSA_T_RT)
src = ospf_hash_find_rt(po->gr, oa->areaid, px->ref_rt);
else
src = ospf_hash_find(po->gr, oa->areaid, px->ref_id, px->ref_rt, px->ref_type);
if (!src)
continue;
/* Reachable in SPF */
if (src->color != INSPF)
continue;
if ((src->lsa.type != LSA_T_RT) && (src->lsa.type != LSA_T_NET))
continue;
buf = px->rest;
for (i = 0; i < px->pxcount; i++)
{
buf = lsa_get_ipv6_prefix(buf, &pxa, &pxlen, &pxopts, &metric);
if (pxopts & OPT_PX_NU)
continue;
/* Store the first global address to use it later as a vlink endpoint */
if ((pxopts & OPT_PX_LA) && ipa_zero(src->lb))
src->lb = pxa;
add_network(oa, pxa, pxlen, src->dist + metric, src);
}
}
}
#endif
static void
ospf_rt_spfa_rtlinks(struct ospf_area *oa, struct top_hash_entry *act, struct top_hash_entry *en)
{
// struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
u32 i;
struct ospf_lsa_rt *rt = en->lsa_body;
struct ospf_lsa_rt_link *rr = (struct ospf_lsa_rt_link *) (rt + 1);
for (i = 0; i < lsa_rt_count(&en->lsa); i++)
{
struct ospf_lsa_rt_link *rtl = rr + i;
struct top_hash_entry *tmp = NULL;
DBG(" Working on link: %R (type: %u) ", rtl->id, rtl->type);
switch (rtl->type)
{
#ifdef OSPFv2
case LSART_STUB:
/* This violates RFC 2328! But it is mostly harmless. */
add_network(oa, ipa_from_u32(rtl->id),
ipa_mklen(ipa_from_u32(rtl->data)),
act->dist + rtl->metric, act);
break;
#endif
case LSART_NET:
#ifdef OSPFv2
/* In OSPFv2, rtl->id is IP addres of DR, Router ID is not known */
tmp = ospf_hash_find_net(po->gr, oa->areaid, rtl->id);
#else /* OSPFv3 */
tmp = ospf_hash_find(po->gr, oa->areaid, rtl->nif, rtl->id, LSA_T_NET);
#endif
break;
case LSART_VLNK:
case LSART_PTP:
tmp = ospf_hash_find_rt(po->gr, oa->areaid, rtl->id);
break;
default:
log("Unknown link type in router lsa. (rid = %R)", act->lsa.id);
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);
}
}
/* RFC 2328 16.1. calculating shortest paths for an area */
static void
ospf_rt_spfa(struct ospf_area *oa)
{
struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
struct ospf_lsa_rt *rt;
struct ospf_lsa_net *ln;
struct top_hash_entry *act, *tmp;
u32 i, *rts;
node *n;
if (oa->rt == NULL)
return;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for area %R", oa->areaid);
/* 16.1. (1) */
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: %R, id: %R, type: %u\n",
oa->rt->lsa.rt, oa->rt->lsa.id, oa->rt->lsa.type);
while (!EMPTY_LIST(oa->cand))
{
n = HEAD(oa->cand);
act = SKIP_BACK(struct top_hash_entry, cn, n);
rem_node(n);
DBG("Working on LSA: rt: %R, id: %R, 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->options & OPT_RT_V)
oa->trcap = 1;
/*
* In OSPFv3, all routers are added to per-area routing
* tables. But we use it just for ASBRs and ABRs. For the
* purpose of the last step in SPF - prefix-LSA processing in
* process_prefixes(), we use information stored in LSA db.
*/
if (((rt->options & OPT_RT_E) || (rt->options & OPT_RT_B))
&& (act->lsa.rt != po->router_id))
{
orta nf = {
.type = RTS_OSPF,
.options = rt->options,
.metric1 = act->dist,
.metric2 = LSINFINITY,
.tag = 0,
.rid = act->lsa.rt,
.oa = oa,
.ifa = act->nhi,
.nh = act->nh
};
ri_install_rt(oa, act->lsa.rt, &nf);
}
#ifdef OSPFv2
ospf_rt_spfa_rtlinks(oa, act, act);
#else /* OSPFv3 */
for (tmp = ospf_hash_find_rt_first(po->gr, act->domain, act->lsa.rt);
tmp; tmp = ospf_hash_find_rt_next(tmp))
ospf_rt_spfa_rtlinks(oa, act, tmp);
#endif
break;
case LSA_T_NET:
ln = act->lsa_body;
#ifdef OSPFv2
add_network(oa, ipa_and(ipa_from_u32(act->lsa.id), ln->netmask),
ipa_mklen(ln->netmask), act->dist, act);
#endif
rts = (u32 *) (ln + 1);
for (i = 0; i < lsa_net_count(&act->lsa); i++)
{
DBG(" Working on router %R ", rts[i]);
tmp = ospf_hash_find_rt(po->gr, oa->areaid, rts[i]);
if (tmp != NULL)
DBG("Found :-)\n");
else
DBG("Not found!\n");
add_cand(&oa->cand, tmp, act, act->dist, oa);
}
break;
}
}
#ifdef OSPFv3
process_prefixes(oa);
#endif
}
static int
link_back(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry *par)
{
u32 i, *rts;
struct ospf_lsa_net *ln;
struct ospf_lsa_rt *rt;
struct ospf_lsa_rt_link *rtl, *rr;
struct top_hash_entry *tmp;
struct proto_ospf *po = oa->po;
if (!en || !par) return 0;
/* In OSPFv2, en->lb is set here. In OSPFv3, en->lb is just cleared here,
it is set in process_prefixes() to any global addres in the area */
en->lb = IPA_NONE;
#ifdef OSPFv3
en->lb_id = 0;
#endif
switch (en->lsa.type)
{
case LSA_T_RT:
rt = (struct ospf_lsa_rt *) en->lsa_body;
rr = (struct ospf_lsa_rt_link *) (rt + 1);
for (i = 0; i < lsa_rt_count(&en->lsa); i++)
{
rtl = (rr + i);
switch (rtl->type)
{
case LSART_STUB:
break;
case LSART_NET:
#ifdef OSPFv2
/* In OSPFv2, rtl->id is IP addres of DR, Router ID is not known */
tmp = ospf_hash_find_net(po->gr, oa->areaid, rtl->id);
#else /* OSPFv3 */
tmp = ospf_hash_find(po->gr, oa->areaid, rtl->nif, rtl->id, LSA_T_NET);
#endif
if (tmp == par)
{
#ifdef OSPFv2
en->lb = ipa_from_u32(rtl->data);
#else /* OSPFv3 */
en->lb_id = rtl->lif;
#endif
return 1;
}
break;
case LSART_VLNK:
case LSART_PTP:
tmp = ospf_hash_find_rt(po->gr, oa->areaid, rtl->id);
if (tmp == par)
return 1;
break;
default:
log(L_WARN "Unknown link type in router lsa. (rid = %R)", en->lsa.rt);
break;
}
}
break;
case LSA_T_NET:
ln = en->lsa_body;
rts = (u32 *) (ln + 1);
for (i = 0; i < lsa_net_count(&en->lsa); i++)
{
tmp = ospf_hash_find_rt(po->gr, oa->areaid, rts[i]);
if (tmp == par)
return 1;
}
break;
default:
bug("Unknown lsa type %x.", en->lsa.type);
}
return 0;
}
/* RFC 2328 16.2. calculating inter-area routes */
static void
ospf_rt_sum(struct ospf_area *oa)
{
struct proto_ospf *po = oa->po;
struct proto *p = &po->proto;
struct top_hash_entry *en;
ip_addr ip = IPA_NONE;
u32 dst_rid = 0;
u32 metric, options;
ort *abr;
int pxlen = -1, type = -1;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for inter-area (area %R)", oa->areaid);
WALK_SLIST(en, po->lsal)
{
if ((en->lsa.type != LSA_T_SUM_RT) && (en->lsa.type != LSA_T_SUM_NET))
continue;
if (en->domain != oa->areaid)
continue;
/* 16.2. (1a) */
if (en->lsa.age == LSA_MAXAGE)
continue;
/* 16.2. (2) */
if (en->lsa.rt == po->router_id)
continue;
/* 16.2. (3) is handled later in ospf_rt_abr() by resetting such rt entry */
if (en->lsa.type == LSA_T_SUM_NET)
{
#ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body;
pxlen = ipa_mklen(ls->netmask);
ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask);
#else /* OSPFv3 */
u8 pxopts;
u16 rest;
struct ospf_lsa_sum_net *ls = en->lsa_body;
lsa_get_ipv6_prefix(ls->prefix, &ip, &pxlen, &pxopts, &rest);
if (pxopts & OPT_PX_NU)
continue;
#endif
metric = ls->metric & METRIC_MASK;
options = 0;
type = ORT_NET;
}
else /* LSA_T_SUM_RT */
{
#ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body;
dst_rid = en->lsa.id;
options = 0;
#else /* OSPFv3 */
struct ospf_lsa_sum_rt *ls = en->lsa_body;
dst_rid = ls->drid;
options = ls->options & OPTIONS_MASK;
#endif
/* We don't want local router in ASBR routing table */
if (dst_rid == po->router_id)
continue;
metric = ls->metric & METRIC_MASK;
options |= ORTA_ASBR;
type = ORT_ROUTER;
}
/* 16.2. (1b) */
if (metric == LSINFINITY)
continue;
/* 16.2. (4) */
ip_addr abrip = ipa_from_rid(en->lsa.rt);
abr = (ort *) fib_find(&oa->rtr, &abrip, MAX_PREFIX_LENGTH);
if (!abr || !abr->n.type)
continue;
if (!(abr->n.options & ORTA_ABR))
continue;
/* This check is not mentioned in RFC 2328 */
if (abr->n.type != RTS_OSPF)
continue;
/* 16.2. (5) */
orta nf = {
.type = RTS_OSPF_IA,
.options = options,
.metric1 = abr->n.metric1 + metric,
.metric2 = LSINFINITY,
.tag = 0,
.rid = en->lsa.rt, /* ABR ID */
.oa = oa,
.ifa = abr->n.ifa,
.nh = abr->n.nh
};
if (type == ORT_NET)
ri_install_net(po, ip, pxlen, &nf);
else
ri_install_rt(oa, dst_rid, &nf);
}
}
/* RFC 2328 16.3. examining summary-LSAs in transit areas */
static void
ospf_rt_sum_tr(struct ospf_area *oa)
{
// struct proto *p = &oa->po->proto;
struct proto_ospf *po = oa->po;
struct ospf_area *bb = po->backbone;
ip_addr abrip;
struct top_hash_entry *en;
u32 dst_rid, metric;
ort *re = NULL, *abr;
if (!bb) return;
WALK_SLIST(en, po->lsal)
{
if ((en->lsa.type != LSA_T_SUM_RT) && (en->lsa.type != LSA_T_SUM_NET))
continue;
if (en->domain != oa->areaid)
continue;
/* 16.3 (1a) */
if (en->lsa.age == LSA_MAXAGE)
continue;
/* 16.3 (2) */
if (en->lsa.rt == po->router_id)
continue;
if (en->lsa.type == LSA_T_SUM_NET)
{
ip_addr ip;
int pxlen;
#ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body;
pxlen = ipa_mklen(ls->netmask);
ip = ipa_and(ipa_from_u32(en->lsa.id), ls->netmask);
#else /* OSPFv3 */
u8 pxopts;
u16 rest;
struct ospf_lsa_sum_net *ls = en->lsa_body;
lsa_get_ipv6_prefix(ls->prefix, &ip, &pxlen, &pxopts, &rest);
if (pxopts & OPT_PX_NU)
continue;
#endif
metric = ls->metric & METRIC_MASK;
re = fib_find(&po->rtf, &ip, pxlen);
}
else // en->lsa.type == LSA_T_SUM_RT
{
#ifdef OSPFv2
struct ospf_lsa_sum *ls = en->lsa_body;
dst_rid = en->lsa.id;
#else /* OSPFv3 */
struct ospf_lsa_sum_rt *ls = en->lsa_body;
dst_rid = ls->drid;
#endif
metric = ls->metric & METRIC_MASK;
ip_addr ip = ipa_from_rid(dst_rid);
re = fib_find(&bb->rtr, &ip, MAX_PREFIX_LENGTH);
}
/* 16.3 (1b) */
if (metric == LSINFINITY)
continue;
/* 16.3 (3) */
if (!re || !re->n.type)
continue;
if (re->n.oa->areaid != 0)
continue;
if ((re->n.type != RTS_OSPF) && (re->n.type != RTS_OSPF_IA))
continue;
/* 16.3. (4) */
abrip = ipa_from_rid(en->lsa.rt);
abr = fib_find(&oa->rtr, &abrip, MAX_PREFIX_LENGTH);
if (!abr || !abr->n.type)
continue;
metric = abr->n.metric1 + metric; /* IAC */
/* 16.3. (5) */
if (metric <= re->n.metric1)
{
/* We want to replace the next-hop even if the metric is equal
to replace a virtual next-hop through vlink with a real one */
re->n.metric1 = metric;
re->n.nh = abr->n.nh;
re->n.ifa = abr->n.ifa;
}
}
}
/* Decide about originating or flushing summary LSAs for condended area networks */
static int
decide_anet_lsa(struct ospf_area *oa, struct area_net *anet, struct ospf_area *anet_oa)
{
if (oa->stub)
return 0;
if (oa == anet_oa)
return 0;
/* Do not condense routing info when exporting from backbone to the transit area */
if ((anet_oa == oa->po->backbone) && oa->trcap)
return 0;
return (anet->active && !anet->hidden);
}
/* Decide about originating or flushing summary LSAs (12.4.3) */
static int
decide_sum_lsa(struct ospf_area *oa, ort *nf, int dest)
{
/* 12.4.3.1. - do not send summary into stub areas, we send just default route */
if (oa->stub)
return 0;
/* Invalid field - no route */
if (!nf->n.type)
return 0;
/* 12.4.3 p2 */
if (nf->n.type > RTS_OSPF_IA)
return 0;
/* 12.4.3 p3 */
if ((nf->n.oa->areaid == oa->areaid))
return 0;
/* 12.4.3 p4 */
if (nf->n.ifa->oa->areaid == oa->areaid)
return 0;
/* 12.4.3 p5 */
if (nf->n.metric1 >= LSINFINITY)
return 0;
/* 12.4.3 p6 - AS boundary router */
if (dest == ORT_ROUTER)
{
/* We call decide_sum_lsa() on preferred ASBR entries, no need for 16.4. (3) */
/* 12.4.3 p1 */
return (nf->n.options & ORTA_ASBR);
}
/* 12.4.3 p7 - inter-area route */
if (nf->n.type == RTS_OSPF_IA)
{
/* Inter-area routes are not repropagated into the backbone */
return (oa != oa->po->backbone);
}
/* 12.4.3 p8 - intra-area route */
/* Do not condense routing info when exporting from backbone to the transit area */
if ((nf->n.oa == oa->po->backbone) && oa->trcap)
return 1;
struct area_net *anet = (struct area_net *)
fib_route(&nf->n.oa->net_fib, nf->fn.prefix, nf->fn.pxlen);
/* Condensed area network found */
if (anet)
return 0;
return 1;
}
/* RFC 2328 16.7. p1 - originate or flush summary LSAs */
static inline void
check_sum_net_lsa(struct proto_ospf *po, ort *nf)
{
struct area_net *anet = NULL;
struct ospf_area *anet_oa;
/* RT entry marked as area network */
if (nf->fn.x0)
{
/* It is a default route for stub areas, handled entirely in ospf_rt_abr() */
if (nf->fn.pxlen == 0)
return;
/* Find that area network */
WALK_LIST(anet_oa, po->area_list)
{
anet = (struct area_net *) fib_find(&anet_oa->net_fib, &nf->fn.prefix, nf->fn.pxlen);
if (anet)
break;
}
}
struct ospf_area *oa;
WALK_LIST(oa, po->area_list)
{
if (anet && decide_anet_lsa(oa, anet, anet_oa))
originate_sum_net_lsa(oa, &nf->fn, anet->metric);
else if (decide_sum_lsa(oa, nf, ORT_NET))
originate_sum_net_lsa(oa, &nf->fn, nf->n.metric1);
else
flush_sum_lsa(oa, &nf->fn, ORT_NET);
}
}
static inline void
check_sum_rt_lsa(struct proto_ospf *po, ort *nf)
{
struct ospf_area *oa;
WALK_LIST(oa, po->area_list)
{
if (decide_sum_lsa(oa, nf, ORT_ROUTER))
originate_sum_rt_lsa(oa, &nf->fn, nf->n.metric1, nf->n.options);
else
flush_sum_lsa(oa, &nf->fn, ORT_ROUTER);
}
}
/* RFC 2328 16.7. p2 - find new/lost vlink endpoints */
static void
ospf_check_vlinks(struct proto_ospf *po)
{
struct proto *p = &po->proto;
struct ospf_iface *iface;
WALK_LIST(iface, po->iface_list)
{
if (iface->type == OSPF_IT_VLINK)
{
struct top_hash_entry *tmp;
tmp = ospf_hash_find_rt(po->gr, iface->voa->areaid, iface->vid);
if (tmp && (tmp->color == INSPF) && ipa_nonzero(tmp->lb))
{
if ((iface->state != OSPF_IS_PTP)
|| (iface->vifa != tmp->nhi)
|| !ipa_equal(iface->vip, tmp->lb))
{
OSPF_TRACE(D_EVENTS, "Vlink peer %R found", tmp->lsa.id);
ospf_iface_sm(iface, ISM_DOWN);
iface->vifa = tmp->nhi;
iface->iface = tmp->nhi->iface;
iface->addr = tmp->nhi->addr;
iface->sk = tmp->nhi->sk;
iface->cost = tmp->dist;
iface->vip = tmp->lb;
ospf_iface_sm(iface, ISM_UP);
}
else if ((iface->state == OSPF_IS_PTP) && (iface->cost != tmp->dist))
{
iface->cost = tmp->dist;
schedule_rt_lsa(po->backbone);
}
}
else
{
if (iface->state > OSPF_IS_DOWN)
{
OSPF_TRACE(D_EVENTS, "Vlink peer %R lost", iface->vid);
ospf_iface_sm(iface, ISM_DOWN);
}
}
}
}
}
/* Miscellaneous route processing that needs to be done by ABRs */
static void
ospf_rt_abr(struct proto_ospf *po)
{
struct area_net *anet;
ort *nf, *default_nf;
FIB_WALK(&po->rtf, nftmp)
{
nf = (ort *) nftmp;
/* RFC 2328 G.3 - incomplete resolution of virtual next hops */
if (nf->n.type && (nf->n.ifa->type == OSPF_IT_VLINK))
reset_ri(&nf->n);
/* Compute condensed area networks */
if (nf->n.type == RTS_OSPF)
{
anet = (struct area_net *) fib_route(&nf->n.oa->net_fib, nf->fn.prefix, nf->fn.pxlen);
if (anet)
{
if (!anet->active)
{
anet->active = 1;
/* Get a RT entry and mark it to know that it is an area network */
ort *nfi = (ort *) fib_get(&po->rtf, &anet->fn.prefix, anet->fn.pxlen);
nfi->fn.x0 = 1; /* mark and keep persistent, to have stable UID */
/* 16.2. (3) */
if (nfi->n.type == RTS_OSPF_IA)
reset_ri(&nfi->n);
}
if (anet->metric < nf->n.metric1)
anet->metric = nf->n.metric1;
}
}
}
FIB_WALK_END;
ip_addr addr = IPA_NONE;
default_nf = (ort *) fib_get(&po->rtf, &addr, 0);
default_nf->fn.x0 = 1; /* keep persistent */
struct ospf_area *oa;
WALK_LIST(oa, po->area_list)
{
/* 12.4.3.1. - originate or flush default summary LSA for stub areas */
if (oa->stub)
originate_sum_net_lsa(oa, &default_nf->fn, oa->stub);
else
flush_sum_lsa(oa, &default_nf->fn, ORT_NET);
/* RFC 2328 16.4. (3) - precompute preferred ASBR entries */
FIB_WALK(&oa->rtr, nftmp)
{
nf = (ort *) nftmp;
if (nf->n.options & ORTA_ASBR)
ri_install_asbr(po, &nf->fn.prefix, &nf->n);
}
FIB_WALK_END;
}
/* Originate or flush ASBR summary LSAs */
FIB_WALK(&po->backbone->rtr, nftmp)
{
check_sum_rt_lsa(po, (ort *) nftmp);
}
FIB_WALK_END;
/* RFC 2328 16.7. p2 - find new/lost vlink endpoints */
ospf_check_vlinks(po);
}
/* Like fib_route(), but ignores dummy rt entries */
static void *
ospf_fib_route(struct fib *f, ip_addr a, int len)
{
ip_addr a0;
ort *nf;
while (len >= 0)
{
a0 = ipa_and(a, ipa_mkmask(len));
nf = fib_find(f, &a0, len);
if (nf && nf->n.type)
return nf;
len--;
}
return NULL;
}
/* RFC 2328 16.4. calculating external routes */
static void
ospf_ext_spf(struct proto_ospf *po)
{
ort *nf1, *nf2;
orta nfa;
struct top_hash_entry *en;
struct proto *p = &po->proto;
struct ospf_lsa_ext *le;
int pxlen, ebit, rt_fwaddr_valid;
ip_addr ip, nh, rtid, rt_fwaddr;
struct ospf_iface *nhi = NULL;
u32 br_metric, rt_metric, rt_tag;
struct ospf_area *atmp;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation for ext routes");
WALK_SLIST(en, po->lsal)
{
/* 16.4. (1) */
if (en->lsa.type != LSA_T_EXT)
continue;
if (en->lsa.age == LSA_MAXAGE)
continue;
/* 16.4. (2) */
if (en->lsa.rt == po->router_id)
continue;
DBG("%s: Working on LSA. ID: %R, RT: %R, Type: %u\n",
p->name, en->lsa.id, en->lsa.rt, en->lsa.type);
le = en->lsa_body;
rt_metric = le->metric & METRIC_MASK;
ebit = le->metric & LSA_EXT_EBIT;
if (rt_metric == LSINFINITY)
continue;
#ifdef OSPFv2
ip = ipa_and(ipa_from_u32(en->lsa.id), le->netmask);
pxlen = ipa_mklen(le->netmask);
rt_fwaddr = le->fwaddr;
rt_fwaddr_valid = !ipa_equal(rt_fwaddr, IPA_NONE);
rt_tag = le->tag;
#else /* OSPFv3 */
u8 pxopts;
u16 rest;
u32 *buf = le->rest;
buf = lsa_get_ipv6_prefix(buf, &ip, &pxlen, &pxopts, &rest);
if (pxopts & OPT_PX_NU)
continue;
rt_fwaddr_valid = le->metric & LSA_EXT_FBIT;
if (rt_fwaddr_valid)
buf = lsa_get_ipv6_addr(buf, &rt_fwaddr);
else
rt_fwaddr = IPA_NONE;
if (le->metric & LSA_EXT_TBIT)
rt_tag = *buf++;
else
rt_tag = 0;
#endif
if (pxlen < 0)
{
log(L_WARN "%s: Invalid mask in LSA (Type: %04x, Id: %R, Rt: %R)",
p->name, en->lsa.type, en->lsa.id, en->lsa.rt);
continue;
}
nhi = NULL;
nh = IPA_NONE;
/* 16.4. (3) */
/* If there are more areas, we already precomputed preferred ASBR entries
in ospf_asbr_spf() and stored them in the backbone table */
atmp = (po->areano > 1) ? po->backbone : HEAD(po->area_list);
rtid = ipa_from_rid(en->lsa.rt);
nf1 = fib_find(&atmp->rtr, &rtid, MAX_PREFIX_LENGTH);
if (!nf1 || !nf1->n.type)
continue; /* No AS boundary router found */
if (!(nf1->n.options & ORTA_ASBR))
continue; /* It is not ASBR */
if (!rt_fwaddr_valid)
{
nf2 = nf1;
nh = nf1->n.nh;
nhi = nf1->n.ifa;
br_metric = nf1->n.metric1;
}
else
{
nf2 = ospf_fib_route(&po->rtf, rt_fwaddr, MAX_PREFIX_LENGTH);
if (!nf2)
continue;
if ((nf2->n.type != RTS_OSPF) && (nf2->n.type != RTS_OSPF_IA))
continue;
/* If nh is zero, it is a device route */
nh = ipa_nonzero(nf2->n.nh) ? nf2->n.nh : rt_fwaddr;
nhi = nf2->n.ifa;
br_metric = nf2->n.metric1;
}
if (ebit)
{
nfa.type = RTS_OSPF_EXT2;
nfa.metric1 = br_metric;
nfa.metric2 = rt_metric;
}
else
{
nfa.type = RTS_OSPF_EXT1;
nfa.metric1 = br_metric + rt_metric;
nfa.metric2 = LSINFINITY;
}
/* Mark the LSA as reachable */
en->color = INSPF;
/* Whether the route is preferred in route selection according to 16.4.1 */
nfa.options = epath_preferred(&nf2->n) ? ORTA_PREF : 0;
nfa.tag = rt_tag;
nfa.rid = en->lsa.rt;
nfa.oa = nf1->n.oa; /* undefined in RFC 2328 */
nfa.ifa = nhi;
nfa.nh = nh;
ri_install_ext(po, ip, pxlen, &nfa);
}
}
/* Cleanup of routing tables and data Cleanup */
void
ospf_rt_reset(struct proto_ospf *po)
{
struct ospf_area *oa;
struct top_hash_entry *en;
struct area_net *anet;
ort *ri;
/* Reset old routing table */
FIB_WALK(&po->rtf, nftmp)
{
ri = (ort *) nftmp;
memcpy(&ri->o, &ri->n, sizeof(orta)); /* Backup old data */
ri->fn.x0 = 0;
reset_ri(&ri->n);
}
FIB_WALK_END;
/* Reset SPF data in LSA db */
WALK_SLIST(en, po->lsal)
{
en->color = OUTSPF;
en->dist = LSINFINITY;
en->nhi = NULL;
en->nh = IPA_NONE;
en->lb = IPA_NONE;
}
WALK_LIST(oa, po->area_list)
{
/* Reset ASBR routing tables */
FIB_WALK(&oa->rtr, nftmp)
{
ri = (ort *) nftmp;
memcpy(&ri->o, &ri->n, sizeof(orta)); /* Backup old data */
reset_ri(&ri->n);
}
FIB_WALK_END;
/* Reset condensed area networks */
if (po->areano > 1)
{
FIB_WALK(&oa->net_fib, nftmp)
{
anet = (struct area_net *) nftmp;
anet->active = 0;
anet->metric = 0;
}
FIB_WALK_END;
}
}
}
/**
* 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.
* This function is invoked from ospf_disp().
*/
void
ospf_rt_spf(struct proto_ospf *po)
{
struct proto *p = &po->proto;
struct ospf_area *oa;
if (po->areano == 0)
return;
OSPF_TRACE(D_EVENTS, "Starting routing table calculation");
/* 16. (1) */
ospf_rt_reset(po);
/* 16. (2) */
WALK_LIST(oa, po->area_list)
ospf_rt_spfa(oa);
/* 16. (3) */
if (po->areano == 1)
ospf_rt_sum(HEAD(po->area_list));
else
ospf_rt_sum(po->backbone);
/* 16. (4) */
WALK_LIST(oa, po->area_list)
if (oa->trcap && (oa->areaid != 0))
ospf_rt_sum_tr(oa);
if (po->areano > 1)
ospf_rt_abr(po);
/* 16. (5) */
ospf_ext_spf(po);
rt_sync(po);
po->calcrt = 0;
}
/* 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,
u32 dist, struct ospf_area *oa)
{
node *prev, *n;
int added = 0;
struct top_hash_entry *act;
/* 16.1. (2b) */
if (en == NULL)
return;
if (en->lsa.age == LSA_MAXAGE)
return;
#ifdef OSPFv3
if (en->lsa.type == LSA_T_RT)
{
struct ospf_lsa_rt *rt = en->lsa_body;
if (!(rt->options & OPT_V6) || !(rt->options & OPT_R))
return;
}
#endif
/* 16.1. (2c) */
if (en->color == INSPF)
return;
/* 16.1. (2d), also checks that dist < LSINFINITY */
if (dist >= en->dist)
return;
/*
* The line above (=) is not a bug, but we don't support multiple
* next hops. I'll start as soon as nest will
*/
/* We should check whether there is a reverse link from en to par, */
if (!link_back(oa, en, par))
return;
if (!calc_next_hop(oa, en, par))
{
log(L_WARN "Cannot find next hop for LSA (Type: %04x, Id: %R, Rt: %R)",
en->lsa.type, en->lsa.id, en->lsa.rt);
return;
}
DBG(" Adding candidate: rt: %R, id: %R, type: %u\n",
en->lsa.rt, en->lsa.id, en->lsa.type);
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)))
/* FIXME - shouldn't be here LSA_T_RT ??? */
{
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);
}
}
}
static inline int
match_dr(struct ospf_iface *ifa, struct top_hash_entry *en)
{
#ifdef OSPFv2
return (ifa->drid == en->lsa.rt) && (ipa_to_u32(ifa->drip) == en->lsa.id);
#else /* OSPFv3 */
return (ifa->drid == en->lsa.rt) && (ifa->dr_iface_id == en->lsa.id);
#endif
}
static int
calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
struct top_hash_entry *par)
{
// struct proto *p = &oa->po->proto;
struct ospf_neighbor *neigh, *m;
struct proto_ospf *po = oa->po;
struct ospf_iface *ifa;
/* 16.1.1. The next hop calculation */
DBG(" Next hop called.\n");
if (ipa_zero(par->nh))
{
u32 rid = en->lsa.rt;
DBG(" Next hop calculating for id: %R rt: %R type: %u\n",
en->lsa.id, en->lsa.rt, en->lsa.type);
/*
* There are three cases:
* 1) en is a local network (and par is root)
* 2) en is a ptp or ptmp neighbor (and par is root)
* 3) en is a bcast or nbma neighbor (and par is local network)
*/
/* The first case - local network */
if ((en->lsa.type == LSA_T_NET) && (par == oa->rt))
{
WALK_LIST(ifa, po->iface_list)
if (match_dr(ifa, en))
{
en->nh = IPA_NONE;
en->nhi = ifa;
return 1;
}
return 0;
}
/* The second case - ptp or ptmp neighbor */
if ((en->lsa.type == LSA_T_RT) && (par == oa->rt))
{
/*
* We don't know which iface was used to reach this neighbor
* (there might be more parallel ifaces) so we will find
* the best PTP iface with given fully adjacent neighbor.
*/
neigh = NULL;
WALK_LIST(ifa, po->iface_list)
if ((ifa->type == OSPF_IT_PTP) || (ifa->type == OSPF_IT_VLINK))
{
m = find_neigh(ifa, rid);
if (m && (m->state == NEIGHBOR_FULL))
{
if (!neigh || (m->ifa->cost < neigh->ifa->cost))
neigh = m;
}
}
if (!neigh)
return 0;
en->nh = neigh->ip;
en->nhi = neigh->ifa;
return 1;
}
/* The third case - bcast or nbma neighbor */
if ((en->lsa.type == LSA_T_RT) && (par->lsa.type == LSA_T_NET))
{
/* par->nhi should be defined from parent's calc_next_hop() */
if (!par->nhi)
goto bad;
#ifdef OSPFv2
/*
* In this case, next-hop is the same as link-back, which is
* already computed in link_back().
*/
if (ipa_zero(en->lb))
goto bad;
en->nh = en->lb;
en->nhi = par->nhi;
return 1;
#else /* OSPFv3 */
/*
* Next-hop is taken from lladdr field of Link-LSA, en->lb_id
* is computed in link_back().
*/
struct top_hash_entry *lhe;
lhe = ospf_hash_find(po->gr, par->nhi->iface->index, en->lb_id, rid, LSA_T_LINK);
if (!lhe)
return 0;
struct ospf_lsa_link *llsa = lhe->lsa_body;
if (ipa_zero(llsa->lladdr))
return 0;
en->nh = llsa->lladdr;
en->nhi = par->nhi;
return 1;
#endif
}
bad:
/* Probably bug or some race condition, we log it */
log(L_ERR "Unexpected case in next hop calculation");
return 0;
}
en->nh = par->nh;
en->nhi = par->nhi;
return 1;
}
static void
rt_sync(struct proto_ospf *po)
{
struct proto *p = &po->proto;
struct fib_iterator fit;
struct fib *fib = &po->rtf;
ort *nf;
struct ospf_area *oa;
/* This is used for forced reload of routes */
int reload = (po->calcrt == 2);
OSPF_TRACE(D_EVENTS, "Starting routing table synchronisation");
DBG("Now syncing my rt table with nest's\n");
FIB_ITERATE_INIT(&fit, fib);
again1:
FIB_ITERATE_START(fib, &fit, nftmp)
{
nf = (ort *) nftmp;
/* Sanity check of next-hop address */
if (nf->n.type && ipa_nonzero(nf->n.nh))
{
neighbor *ng = neigh_find2(p, &nf->n.nh, nf->n.ifa->iface, 0);
if (!ng || (ng->scope == SCOPE_HOST))
reset_ri(&nf->n);
}
if (po->areano > 1)
check_sum_net_lsa(po, nf);
if (reload || memcmp(&nf->n, &nf->o, sizeof(orta)))
{
net *ne = net_get(p->table, nf->fn.prefix, nf->fn.pxlen);
if (nf->n.type) /* Add the route */
{
rta a0 = {
.proto = p,
.source = nf->n.type,
.scope = SCOPE_UNIVERSE,
.cast = RTC_UNICAST,
.iface = nf->n.ifa->iface
};
if (ipa_nonzero(nf->n.nh))
{
a0.dest = RTD_ROUTER;
a0.gw = nf->n.nh;
}
else
a0.dest = RTD_DEVICE;
rte *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->u.ospf.router_id = nf->n.rid;
e->pflags = 0;
e->net = ne;
e->pref = p->preference;
DBG("Mod rte type %d - %I/%d via %I on iface %s, met %d\n",
a0.source, nf->fn.prefix, nf->fn.pxlen, a0.gw, a0.iface ? a0.iface->name : "(none)", nf->n.metric1);
rte_update(p->table, ne, p, p, e);
}
else /* Remove the route */
rte_update(p->table, ne, p, p, NULL);
}
/* Remove unused rt entry. Entries with fn.x0 == 1 are persistent. */
if (!nf->n.type && !nf->fn.x0)
{
FIB_ITERATE_PUT(&fit, nftmp);
fib_delete(fib, nftmp);
goto again1;
}
}
FIB_ITERATE_END(nftmp);
WALK_LIST(oa, po->area_list)
{
/* Cleanup ASBR hash tables */
FIB_ITERATE_INIT(&fit, &oa->rtr);
again2:
FIB_ITERATE_START(&oa->rtr, &fit, nftmp)
{
nf = (ort *) nftmp;
if (!nf->n.type)
{
FIB_ITERATE_PUT(&fit, nftmp);
fib_delete(&oa->rtr, nftmp);
goto again2;
}
}
FIB_ITERATE_END(nftmp);
}
}
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