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zebra: Fix for route node having no tracking NHT

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Topology:
IXIA-----(ens192)FRR(ens224)------iXIA

Configuration:
1. Create 8 sub-interfaces on ens192 under Default VRF and configure 8
EBGP session between FRR and IXIA.
2. Create 1000 sub-interfaces on ens224 under Default VRF and configure
1000 EBGP session between FRR and IXIA.
3. 2M prefixes distributed from Left side Ixia each with 8 ECMP path.
4. So in total, there are 2M prefixes * 8 ECMP = 16M prefixes entries
in RIB and FIB.

Issue:
Shut ens192 and ens224, this is taking 1hr 15 mins to clean up the routes.

Root Cause:
In the case of route deletion, if the particular route node is having
nht count = 0, we are going to the parent and doing nht evaluation,
which is not needed.

Fix:
If the deleted the route node is having nht count > 0, then do a nht
evaluation on the parent node.
Shut ens192 and ens224, it is taking 1 min to clean up the routes
with the fix.

Signed-off-by: Sarita Patra <saritap@vmware.com>
This commit is contained in:
Sarita Patra 2021-06-13 18:48:35 -07:00 committed by Donald Sharp
parent a8057c9db5
commit f99f1ff50a
2 changed files with 17 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
zebra/rib.h
View file

@ -490,7 +490,8 @@ extern struct route_table *rib_tables_iter_next(rib_tables_iter_t *iter);
extern uint8_t route_distance(int type);
extern void zebra_rib_evaluate_rn_nexthops(struct route_node *rn, uint32_t seq);
extern void zebra_rib_evaluate_rn_nexthops(struct route_node *rn, uint32_t seq,
bool rt_delete);
/*
* Inline functions.

20
zebra/zebra_rib.c
View file

@ -698,7 +698,8 @@ static int rib_can_delete_dest(rib_dest_t *dest)
return 1;
}
void zebra_rib_evaluate_rn_nexthops(struct route_node *rn, uint32_t seq)
void zebra_rib_evaluate_rn_nexthops(struct route_node *rn, uint32_t seq,
bool rt_delete)
{
rib_dest_t *dest = rib_dest_from_rnode(rn);
struct rnh *rnh;
@ -719,6 +720,12 @@ void zebra_rib_evaluate_rn_nexthops(struct route_node *rn, uint32_t seq)
__func__, rn,
dest ? rnh_list_count(&dest->nht) : 0);
if (rt_delete && (!dest || !rnh_list_count(&dest->nht))) {
if (IS_ZEBRA_DEBUG_NHT_DETAILED)
zlog_debug("%pRN has no tracking NHTs. Bailing",
rn);
break;
}
if (!dest) {
rn = rn->parent;
if (rn)
@ -798,7 +805,8 @@ int rib_gc_dest(struct route_node *rn)
rnode_debug(rn, zvrf_id(zvrf), "removing dest from table");
}
zebra_rib_evaluate_rn_nexthops(rn, zebra_router_get_next_sequence());
zebra_rib_evaluate_rn_nexthops(rn, zebra_router_get_next_sequence(),
true);
dest->rnode = NULL;
rnh_list_fini(&dest->nht);
@ -1803,6 +1811,7 @@ static void rib_process_result(struct zebra_dplane_ctx *ctx)
rib_dest_t *dest;
bool fib_changed = false;
struct rib_table_info *info;
bool rt_delete = false;
zvrf = vrf_info_lookup(dplane_ctx_get_vrf(ctx));
vrf = vrf_lookup_by_id(dplane_ctx_get_vrf(ctx));
@ -1990,6 +1999,7 @@ static void rib_process_result(struct zebra_dplane_ctx *ctx)
}
break;
case DPLANE_OP_ROUTE_DELETE:
rt_delete = true;
if (re)
SET_FLAG(re->status, ROUTE_ENTRY_FAILED);
/*
@ -2032,7 +2042,7 @@ static void rib_process_result(struct zebra_dplane_ctx *ctx)
break;
}
zebra_rib_evaluate_rn_nexthops(rn, seq);
zebra_rib_evaluate_rn_nexthops(rn, seq, rt_delete);
zebra_rib_evaluate_mpls(rn);
done:
@ -2268,8 +2278,8 @@ static void rib_process_dplane_notify(struct zebra_dplane_ctx *ctx)
}
/* Make any changes visible for lsp and nexthop-tracking processing */
zebra_rib_evaluate_rn_nexthops(
rn, zebra_router_get_next_sequence());
zebra_rib_evaluate_rn_nexthops(rn, zebra_router_get_next_sequence(),
false);
zebra_rib_evaluate_mpls(rn);