OSPF: Fix next hop calculation for PtP links in IPv4 OSPFv3-AF
In such case, next hop has to be taken from Link-LSA like in broadcast case, not from neighbor source address like in other PtP cases. Also add some checks, comments and code cleanup.
This commit is contained in:
Ondrej Zajicek (work)
parent
d3f4f92b0e
commit
f097f7659c
115
proto/ospf/rt.c
115
proto/ospf/rt.c
|
|
@ -10,9 +10,7 @@
|
|||
|
||||
#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, int i);
|
||||
static void add_cand(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry *par, u32 dist, int i, uint lif, uint nif);
|
||||
static void rt_sync(struct ospf_proto *p);
|
||||
|
||||
|
||||
|
|
@ -509,7 +507,7 @@ spfa_process_rt(struct ospf_proto *p, struct ospf_area *oa, struct top_hash_entr
|
|||
break;
|
||||
}
|
||||
|
||||
add_cand(&oa->cand, tmp, act, act->dist + rtl.metric, oa, i);
|
||||
add_cand(oa, tmp, act, act->dist + rtl.metric, i, rtl.lif, rtl.nif);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -532,7 +530,7 @@ spfa_process_net(struct ospf_proto *p, struct ospf_area *oa, struct top_hash_ent
|
|||
for (i = 0; i < cnt; i++)
|
||||
{
|
||||
tmp = ospf_hash_find_rt(p->gr, oa->areaid, ln->routers[i]);
|
||||
add_cand(&oa->cand, tmp, act, act->dist, oa, -1);
|
||||
add_cand(oa, tmp, act, act->dist, -1, 0, 0);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -651,7 +649,8 @@ ospf_rt_spfa(struct ospf_area *oa)
|
|||
}
|
||||
|
||||
static int
|
||||
link_back(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry *par)
|
||||
link_back(struct ospf_area *oa, struct top_hash_entry *en,
|
||||
struct top_hash_entry *par, uint lif, uint nif)
|
||||
{
|
||||
struct ospf_proto *p = oa->po;
|
||||
struct ospf_lsa_rt_walk rtl;
|
||||
|
|
@ -689,6 +688,10 @@ link_back(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry
|
|||
tmp = ospf_hash_find_net(p->gr, oa->areaid, rtl.id, rtl.nif);
|
||||
if (tmp == par)
|
||||
{
|
||||
/*
|
||||
* Note that there may be multiple matching Rt-fields if router 'en'
|
||||
* have multiple interfaces to net 'par'. Perhaps we should do ECMP.
|
||||
*/
|
||||
if (ospf_is_v2(p))
|
||||
en->lb = ipa_from_u32(rtl.data);
|
||||
else
|
||||
|
|
@ -700,7 +703,13 @@ link_back(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry
|
|||
|
||||
case LSART_VLNK:
|
||||
case LSART_PTP:
|
||||
/* Not necessary the same link, see RFC 2328 [23] */
|
||||
/*
|
||||
* For OSPFv2, not necessary the same link, see RFC 2328 [23].
|
||||
* For OSPFv3, we verify that by comparing nif and lif fields.
|
||||
*/
|
||||
if (ospf_is_v3(p) && ((rtl.lif != nif) || (rtl.nif != lif)))
|
||||
break;
|
||||
|
||||
tmp = ospf_hash_find_rt(p->gr, oa->areaid, rtl.id);
|
||||
if (tmp == par)
|
||||
return 1;
|
||||
|
|
@ -1679,13 +1688,27 @@ inherit_nexthops(struct nexthop *pn)
|
|||
return pn && (ipa_nonzero(pn->gw) || !pn->iface);
|
||||
}
|
||||
|
||||
static inline ip_addr
|
||||
link_lsa_lladdr(struct ospf_proto *p, struct top_hash_entry *en)
|
||||
{
|
||||
struct ospf_lsa_link *link_lsa = en->lsa_body;
|
||||
ip6_addr ll = link_lsa->lladdr;
|
||||
|
||||
if (ip6_zero(ll))
|
||||
return IPA_NONE;
|
||||
|
||||
return ospf_is_ip4(p) ? ipa_from_ip4(ospf3_6to4(ll)) : ipa_from_ip6(ll);
|
||||
}
|
||||
|
||||
static struct nexthop *
|
||||
calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
|
||||
struct top_hash_entry *par, int pos)
|
||||
struct top_hash_entry *par, int pos, uint lif, uint nif)
|
||||
{
|
||||
struct ospf_proto *p = oa->po;
|
||||
struct nexthop *pn = par->nhs;
|
||||
struct ospf_iface *ifa;
|
||||
struct top_hash_entry *link = NULL;
|
||||
struct ospf_iface *ifa = NULL;
|
||||
ip_addr nh = IPA_NONE;
|
||||
u32 rid = en->lsa.rt;
|
||||
|
||||
/* 16.1.1. The next hop calculation */
|
||||
|
|
@ -1710,6 +1733,9 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
|
|||
if (!ifa)
|
||||
return NULL;
|
||||
|
||||
if (ospf_is_v3(p) && (ifa->iface_id != lif))
|
||||
log(L_WARN "%s: Inconsistent interface ID %u/%u", p->p.name, ifa->iface_id, lif);
|
||||
|
||||
return new_nexthop(p, IPA_NONE, ifa->iface, ifa->ecmp_weight);
|
||||
}
|
||||
|
||||
|
|
@ -1720,14 +1746,44 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
|
|||
if (!ifa)
|
||||
return NULL;
|
||||
|
||||
if (ospf_is_v3(p) && (ifa->iface_id != lif))
|
||||
log(L_WARN "%s: Inconsistent interface ID %u/%u", p->p.name, ifa->iface_id, lif);
|
||||
|
||||
if (ifa->type == OSPF_IT_VLINK)
|
||||
return new_nexthop(p, IPA_NONE, NULL, 0);
|
||||
|
||||
struct ospf_neighbor *m = find_neigh(ifa, rid);
|
||||
if (!m || (m->state != NEIGHBOR_FULL))
|
||||
return NULL;
|
||||
/* FIXME: On physical PtP links we may skip next-hop altogether */
|
||||
|
||||
return new_nexthop(p, m->ip, ifa->iface, ifa->ecmp_weight);
|
||||
if (ospf_is_v2(p) || ospf_is_ip6(p))
|
||||
{
|
||||
/*
|
||||
* In this case, next-hop is a source address from neighbor's packets.
|
||||
* That is necessary for OSPFv2 and practical for OSPFv3 (as it works even
|
||||
* if neighbor uses LinkLSASuppression), but does not work with OSPFv3-AF
|
||||
* on IPv4 topology, where src is IPv6 but next-hop should be IPv4.
|
||||
*/
|
||||
struct ospf_neighbor *m = find_neigh(ifa, rid);
|
||||
if (!m || (m->state != NEIGHBOR_FULL))
|
||||
return NULL;
|
||||
|
||||
nh = m->ip;
|
||||
}
|
||||
else
|
||||
{
|
||||
/*
|
||||
* Next-hop is taken from lladdr field of Link-LSA, based on Neighbor
|
||||
* Iface ID (nif) field in our Router-LSA, which is just nbr->iface_id.
|
||||
*/
|
||||
link = ospf_hash_find(p->gr, ifa->iface_id, nif, rid, LSA_T_LINK);
|
||||
if (!link)
|
||||
return NULL;
|
||||
|
||||
nh = link_lsa_lladdr(p, link);
|
||||
if (ipa_zero(nh))
|
||||
return NULL;
|
||||
}
|
||||
|
||||
return new_nexthop(p, nh, ifa->iface, ifa->ecmp_weight);
|
||||
}
|
||||
|
||||
/* The third case - bcast or nbma neighbor */
|
||||
|
|
@ -1754,21 +1810,14 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
|
|||
* 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(p->gr, pn->iface->index, en->lb_id, rid, LSA_T_LINK);
|
||||
|
||||
if (!lhe)
|
||||
link = ospf_hash_find(p->gr, pn->iface->index, en->lb_id, rid, LSA_T_LINK);
|
||||
if (!link)
|
||||
return NULL;
|
||||
|
||||
struct ospf_lsa_link *llsa = lhe->lsa_body;
|
||||
|
||||
if (ip6_zero(llsa->lladdr))
|
||||
nh = link_lsa_lladdr(p, link);
|
||||
if (ipa_zero(nh))
|
||||
return NULL;
|
||||
|
||||
ip_addr nh = ospf_is_ip4(p) ?
|
||||
ipa_from_ip4(ospf3_6to4(llsa->lladdr)) :
|
||||
ipa_from_ip6(llsa->lladdr);
|
||||
|
||||
return new_nexthop(p, nh, pn->iface, pn->weight);
|
||||
}
|
||||
}
|
||||
|
|
@ -1782,8 +1831,8 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
|
|||
|
||||
/* 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, int pos)
|
||||
add_cand(struct ospf_area *oa, struct top_hash_entry *en, struct top_hash_entry *par,
|
||||
u32 dist, int pos, uint lif, uint nif)
|
||||
{
|
||||
struct ospf_proto *p = oa->po;
|
||||
node *prev, *n;
|
||||
|
|
@ -1813,10 +1862,10 @@ add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
|
|||
return;
|
||||
|
||||
/* We should check whether there is a reverse link from en to par, */
|
||||
if (!link_back(oa, en, par))
|
||||
if (!link_back(oa, en, par, lif, nif))
|
||||
return;
|
||||
|
||||
struct nexthop *nhs = calc_next_hop(oa, en, par, pos);
|
||||
struct nexthop *nhs = calc_next_hop(oa, en, par, pos, lif, nif);
|
||||
if (!nhs)
|
||||
{
|
||||
log(L_WARN "%s: Cannot find next hop for LSA (Type: %04x, Id: %R, Rt: %R)",
|
||||
|
|
@ -1873,20 +1922,20 @@ add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
|
|||
|
||||
prev = NULL;
|
||||
|
||||
if (EMPTY_LIST(*l))
|
||||
if (EMPTY_LIST(oa->cand))
|
||||
{
|
||||
add_head(l, &en->cn);
|
||||
add_head(&oa->cand, &en->cn);
|
||||
}
|
||||
else
|
||||
{
|
||||
WALK_LIST(n, *l)
|
||||
WALK_LIST(n, oa->cand)
|
||||
{
|
||||
act = SKIP_BACK(struct top_hash_entry, cn, n);
|
||||
if ((act->dist > dist) ||
|
||||
((act->dist == dist) && (act->lsa_type == LSA_T_RT)))
|
||||
{
|
||||
if (prev == NULL)
|
||||
add_head(l, &en->cn);
|
||||
add_head(&oa->cand, &en->cn);
|
||||
else
|
||||
insert_node(&en->cn, prev);
|
||||
added = 1;
|
||||
|
|
@ -1897,7 +1946,7 @@ add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
|
|||
|
||||
if (!added)
|
||||
{
|
||||
add_tail(l, &en->cn);
|
||||
add_tail(&oa->cand, &en->cn);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue