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authorOndrej Zajicek <santiago@crfreenet.org>2009-12-04 22:20:13 +0100
committerOndrej Zajicek <santiago@crfreenet.org>2009-12-04 22:20:13 +0100
commitb76aeb823446616b746b52b5c8152f4c5a73b242 (patch)
tree1a316c1f2cea8b1ada723cb18d1fe3caca8d259b
parent98955023926734c7ecf79f9b8d004baff5225a78 (diff)
downloadbird-b76aeb823446616b746b52b5c8152f4c5a73b242.tar
bird-b76aeb823446616b746b52b5c8152f4c5a73b242.zip
Fixes next hop handling.
-rw-r--r--proto/ospf/rt.c111
1 files changed, 57 insertions, 54 deletions
diff --git a/proto/ospf/rt.c b/proto/ospf/rt.c
index a72a94b..bd19364 100644
--- a/proto/ospf/rt.c
+++ b/proto/ospf/rt.c
@@ -11,9 +11,9 @@
static void add_cand(list * l, struct top_hash_entry *en,
struct top_hash_entry *par, u32 dist,
struct ospf_area *oa);
-static void calc_next_hop(struct ospf_area *oa,
- struct top_hash_entry *en,
- struct top_hash_entry *par);
+static int calc_next_hop(struct ospf_area *oa,
+ struct top_hash_entry *en,
+ struct top_hash_entry *par);
static void ospf_ext_spf(struct proto_ospf *po);
static void rt_sync(struct proto_ospf *po);
@@ -987,18 +987,23 @@ add_cand(list * l, struct top_hash_entry *en, struct top_hash_entry *par,
*/
/* FIXME - fix link_back()
+ * NOTE - we should not change link_back when
+ * it is already computed with different way and calc_next_hop()
+ * for current would fail
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);
- calc_next_hop(oa, en, par);
-
- if (!en->nhi)
- return; /* We cannot find next hop, ignore it */
-
if (en->color == CANDIDATE)
{ /* We found a shorter path */
rem_node(&en->cn);
@@ -1049,7 +1054,7 @@ match_dr(struct ospf_iface *ifa, struct top_hash_entry *en)
#endif
}
-static void
+static int
calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
struct top_hash_entry *par)
{
@@ -1058,9 +1063,6 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
struct proto_ospf *po = oa->po;
struct ospf_iface *ifa;
- en->nhi = NULL;
- en->nh = IPA_NONE;
-
/* 16.1.1. The next hop calculation */
DBG(" Next hop called.\n");
if (ipa_equal(par->nh, IPA_NONE))
@@ -1068,57 +1070,58 @@ calc_next_hop(struct ospf_area *oa, struct top_hash_entry *en,
DBG(" Next hop calculating for id: %R rt: %R type: %u\n",
en->lsa.id, en->lsa.rt, en->lsa.type);
- /* The parent vertex is the root */
- if (par == oa->rt)
+ /*
+ * 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))
{
- if (en->lsa.type == LSA_T_NET)
- {
- WALK_LIST(ifa, po->iface_list)
- if (match_dr(ifa, en))
+ WALK_LIST(ifa, po->iface_list)
+ if (match_dr(ifa, en))
{
- en->nhi = ifa;
- return;
+ en->nh = IPA_NONE;
+ en->nhi = ifa;
+ return 1;
}
- return;
- }
- else
- {
- if ((neigh = find_neigh_noifa(po, en->lsa.rt)) == NULL)
- return;
- en->nhi = neigh->ifa;
- en->nh = neigh->ip;
- /* Yes, neighbor is it's own next hop */
- return;
- }
+ return 0;
}
- /* The parent vertex is a network that directly connects the
- calculating router to the destination router. */
- if (par->lsa.type == LSA_T_NET)
+ /*
+ * Remaining cases - local neighbours.
+ * There are two problems with this code:
+ * 1) we use IP address from HELLO packet
+ * and not the one from LSA (router or link).
+ * This may break NBMA networks
+ * 2) we use find_neigh_noifa() and does not
+ * take into account associated iface.
+ * This breaks neighbors connected by more links.
+ */
+
+ if ((en->lsa.type == LSA_T_RT) &&
+ ((par == oa->rt) || (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;
- 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=%R, PAR=%R)",
- en->lsa.id, par->lsa.id);
- /* I hope this would never happen */
- return;
+ if ((neigh = find_neigh_noifa(po, en->lsa.rt)) != NULL)
+ {
+ en->nh = neigh->ip;
+ en->nhi = neigh->ifa;
+ return 1;
+ }
+ return 0;
}
+
+ /* Probably bug or some race condition, we log it */
+ log(L_ERR "Unexpected case in next hop calculation");
+
+ return 0;
}
- en->nhi = par->nhi;
+
en->nh = par->nh;
- DBG(" Next hop calculated: %I.\n", en->nh);
+ en->nhi = par->nhi;
+ return 1;
}
static void