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OSPF NSSA support, inter-area LSA translation.

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This commit is contained in:
Ondrej Zajicek
2011-08-08 01:45:31 +02:00
parent aca0e79faa
commit ed317862c2
7 changed files with 328 additions and 95 deletions
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242
proto/ospf/rt.c
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@@ -33,7 +33,7 @@ ospf_rt_initort(struct fib_node *fn)
ort *ri = (ort *) fn;
reset_ri(ri);
ri->old_rta = NULL;
ri->fn.x0 = 0;
ri->fn.x0 = ri->fn.x1 = 0;
}
static inline int
@@ -128,6 +128,23 @@ ri_better_asbr(struct proto_ospf *po, orta *new, orta *old)
return 0;
}
static int
orta_prio(orta *nf)
{
/* RFC 3103 2.5 (6e) priorities */
u32 opts = nf->options & (ORTA_NSSA | ORTA_PROP);
/* A Type-7 LSA with the P-bit set */
if (opts == (ORTA_NSSA | ORTA_PROP))
return 2;
/* A Type-5 LSA */
if (opts == 0)
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)
@@ -172,7 +189,19 @@ ri_better_ext(struct proto_ospf *po, orta *new, orta *old)
if (new->metric1 > old->metric1)
return 0;
/* RFC 3103, 2.5. (6e) - missing, is this necessary? */
/* RFC 3103, 2.5. (6e) */
int new_prio = orta_prio(new);
int old_prio = orta_prio(old);
if (new_prio > old_prio)
return 1;
if (old_prio > new_prio)
return 0;
/* make it more deterministic */
if (new->rid > old->rid)
return 1;
return 0;
}
@@ -949,6 +978,96 @@ check_sum_rt_lsa(struct proto_ospf *po, ort *nf)
}
}
static inline int
decide_nssa_lsa(ort *nf, u32 *rt_metric, ip_addr *rt_fwaddr, u32 *rt_tag)
{
struct ospf_area *oa = nf->n.oa;
struct top_hash_entry *en = nf->n.en;
int propagate;
if (!rt_is_nssa(nf) || !oa->translate)
return 0;
/* Condensed area network found */
if (fib_route(&oa->enet_fib, nf->fn.prefix, nf->fn.pxlen))
return 0;
if (!en || (en->lsa.type != LSA_T_NSSA))
return 0;
/* We do not store needed data in struct orta, we have to parse the LSA */
struct ospf_lsa_ext *le = en->lsa_body;
#ifdef OSPFv2
*rt_fwaddr = le->fwaddr;
*rt_tag = le->tag;
propagate = en->lsa.options & OPT_P;
#else /* OSPFv3 */
u32 *buf = le->rest;
u8 pxlen = (*buf >> 24);
u8 pxopts = (*buf >> 16);
buf += IPV6_PREFIX_WORDS(pxlen); /* Skip the IP prefix */
if (pxopts & OPT_PX_NU)
return 0;
if (le->metric & LSA_EXT_FBIT)
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;
propagate = pxopts & OPT_PX_P;
#endif
if (!propagate || ipa_zero(*rt_fwaddr))
return 0;
*rt_metric = le->metric & (METRIC_MASK | LSA_EXT_EBIT);
return 1;
}
/* RFC 3103 3.2 - translating Type-7 LSAs into Type-5 LSAs */
static inline void
check_nssa_lsa(struct proto_ospf *po, ort *nf)
{
struct fib_node *fn = &nf->fn;
struct area_net *anet = NULL;
struct ospf_area *oa = NULL;
u32 rt_metric, rt_tag;
ip_addr rt_fwaddr;
/* Do not translate LSA if there is already the external LSA from route export */
if (fn->x1 == EXT_EXPORT)
return;
/* RT entry marked as area network */
if (fn->x0)
{
/* Find that area network */
WALK_LIST(oa, po->area_list)
{
anet = (struct area_net *) fib_find(&oa->enet_fib, &fn->prefix, fn->pxlen);
if (anet)
break;
}
}
/* RFC 3103 3.2 (3) - originate the aggregated address range */
if (anet && anet->active && !anet->hidden && oa->translate)
originate_ext_lsa(po->backbone, fn, EXT_NSSA, anet->metric, IPA_NONE, anet->tag);
/* RFC 3103 3.2 (2) - originate the same network */
else if (decide_nssa_lsa(nf, &rt_metric, &rt_fwaddr, &rt_tag))
originate_ext_lsa(po->backbone, fn, EXT_NSSA, rt_metric, rt_fwaddr, rt_tag);
else if (fn->x1 == EXT_NSSA)
flush_ext_lsa(po->backbone, fn);
}
/* RFC 2328 16.7. p2 - find new/lost vlink endpoints */
static void
@@ -1000,26 +1119,13 @@ ospf_check_vlinks(struct proto_ospf *po)
}
}
static void
translator_timer_hook(timer *timer)
{
struct ospf_area *oa = timer->data;
if (oa->translate != TRANS_WAIT)
return;
oa->translate = TRANS_OFF;
schedule_rtcalc(oa->po);
}
/* Miscellaneous route processing that needs to be done by ABRs */
static void
ospf_rt_abr(struct proto_ospf *po)
ospf_rt_abr1(struct proto_ospf *po)
{
struct top_hash_entry *en;
struct area_net *anet;
ort *nf, *nf2, *default_nf;
ort *nf, *default_nf;
FIB_WALK(&po->rtf, nftmp)
{
@@ -1087,8 +1193,41 @@ ospf_rt_abr(struct proto_ospf *po)
}
/* 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);
}
static void
translator_timer_hook(timer *timer)
{
struct ospf_area *oa = timer->data;
if (oa->translate != TRANS_WAIT)
return;
oa->translate = TRANS_OFF;
schedule_rtcalc(oa->po);
}
static void
ospf_rt_abr2(struct proto_ospf *po)
{
struct ospf_area *oa;
struct top_hash_entry *en;
ort *nf, *nf2;
/* RFC 3103 3.1 - type-7 translator election */
struct ospf_area *bb = oa->po->backbone;
struct ospf_area *bb = po->backbone;
WALK_LIST(oa, po->area_list)
if (oa_is_nssa(oa))
{
@@ -1143,18 +1282,48 @@ ospf_rt_abr(struct proto_ospf *po)
}
/* Originate or flush ASBR summary LSAs */
FIB_WALK(&po->backbone->rtr, nftmp)
/* Compute condensed external networks */
FIB_WALK(&po->rtf, nftmp)
{
check_sum_rt_lsa(po, (ort *) nftmp);
nf = (ort *) nftmp;
if (rt_is_nssa(nf))
{
struct area_net *anet = (struct area_net *)
fib_route(&nf->n.oa->enet_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 */
nf2 = (ort *) fib_get(&po->rtf, &anet->fn.prefix, anet->fn.pxlen);
nf2->fn.x0 = 1;
}
u32 metric = (nf->n.type == RTS_OSPF_EXT1) ?
nf->n.metric1 : ((nf->n.metric2 + 1) | LSA_EXT_EBIT);
if (anet->metric < metric)
anet->metric = metric;
}
}
}
FIB_WALK_END;
/* RFC 2328 16.7. p2 - find new/lost vlink endpoints */
ospf_check_vlinks(po);
FIB_WALK(&po->rtf, nftmp)
{
nf = (ort *) nftmp;
check_sum_net_lsa(po, nf);
check_nssa_lsa(po, nf);
}
FIB_WALK_END;
}
/* Like fib_route(), but ignores dummy rt entries */
static void *
ospf_fib_route(struct fib *f, ip_addr a, int len)
@@ -1254,7 +1423,7 @@ ospf_ext_spf(struct proto_ospf *po)
/* 16.4. (3) */
/* If there are more areas, we already precomputed preferred ASBR
entries in ospf_rt_abr() and stored them in the backbone
entries in ospf_rt_abr1() and stored them in the backbone
table. For NSSA, we examine the area to which the LSA is assigned */
if (en->lsa.type == LSA_T_EXT)
atmp = ospf_main_area(po);
@@ -1333,12 +1502,17 @@ ospf_ext_spf(struct proto_ospf *po)
/* Whether the route is preferred in route selection according to 16.4.1 */
nfa.options = epath_preferred(&nf2->n) ? ORTA_PREF : 0;
if (en->lsa.type == LSA_T_NSSA)
nfa.options |= ORTA_NSSA;
if (rt_propagate)
nfa.options |= ORTA_PROP;
nfa.tag = rt_tag;
nfa.rid = en->lsa.rt;
nfa.oa = nf1->n.oa; /* undefined in RFC 2328 */
nfa.oa = atmp; /* undefined in RFC 2328 */
nfa.voa = NULL;
nfa.nhs = nhs;
nfa.en = en; /* store LSA for later (NSSA processing) */
ri_install_ext(po, ip, pxlen, &nfa);
}
@@ -1391,6 +1565,14 @@ ospf_rt_reset(struct proto_ospf *po)
anet->metric = 0;
}
FIB_WALK_END;
FIB_WALK(&oa->enet_fib, nftmp)
{
anet = (struct area_net *) nftmp;
anet->active = 0;
anet->metric = 0;
}
FIB_WALK_END;
}
}
}
@@ -1430,11 +1612,14 @@ ospf_rt_spf(struct proto_ospf *po)
ospf_rt_sum_tr(oa);
if (po->areano > 1)
ospf_rt_abr(po);
ospf_rt_abr1(po);
/* 16. (5) */
ospf_ext_spf(po);
if (po->areano > 1)
ospf_rt_abr2(po);
rt_sync(po);
lp_flush(po->nhpool);
@@ -1781,9 +1966,6 @@ again1:
}
}
if (po->areano > 1)
check_sum_net_lsa(po, nf);
/* Remove configured stubnets */
if (!nf->n.nhs)
reset_ri(nf);
@@ -1846,7 +2028,7 @@ again1:
}
/* Remove unused rt entry. Entries with fn.x0 == 1 are persistent. */
if (!nf->n.type && !nf->fn.x0)
if (!nf->n.type && !nf->fn.x0 && !nf->fn.x1)
{
FIB_ITERATE_PUT(&fit, nftmp);
fib_delete(fib, nftmp);