bgpd: EVPN RT-2 advertised with 2 labels for prefix-routes-only config

L3VNI is configured with "prefix-routes-only" flag. Even in this case,
intermittently, we observed that local EVPN MACIP routes are installed and
advertised with 2 labels and 2 export RTs.

This is a sequencing issue. Consider following case where L2VNI 200 and L3VNI
1000 are configured for tenant vrf vrf-blue.

Bug is observed for following sequence of events:
1. vrf-blue BGP instance is created.
2. L2VNI is created in bgp for vni 200. It is linked to the tenant vrf vrf-blue
in function bgpevpn_link_to_l3vni.
Following code sets "VNI_FLAG_USE_TWO_LABELS" flag for vni 200 as L3VNI is not
yet attached to vrf-blue BGP instance.

/* check if we are advertising two labels for this vpn */
if (!CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY))
	SET_FLAG(vpn->flags, VNI_FLAG_USE_TWO_LABELS);

2. Now L3VNI is attached to vrf-blue BGP instance. In this case, we set
BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY flag for vrf-blue but we do not clear
VNI_FLAG_USE_TWO_LABELS flag set on the corresponding L2VNIs.

This fix resolves following 2 issues observed above.
1. When L2VNI is created in BGP, flag VNI_FLAG_USE_TWO_LABELS should not be set
for this VNI if BGP vrf is not attached to any L3VNI.
2. When L3VNI is attached to the BGP vrf, set "VNI_FLAG_USE_TWO_LABELS" flag
if "prefix-routes-only" is not for the vrf.

UT cases:
1. Flap "prefix-routes-only" config for a vrf.
2. Test following triggers for vrfs with and without "prefix-routes-only"
   - Flap L2VNI from kernel.
   - Flap L3VNI from kernel.

Signed-off-by: Ameya Dharkar <adharkar@vmware.com>
This commit is contained in:
Ameya Dharkar 2020-05-07 13:33:02 -07:00
parent faad472899
commit 10f70510b9
2 changed files with 29 additions and 3 deletions

View File

@ -5813,9 +5813,31 @@ int bgp_evpn_local_l3vni_add(vni_t l3vni, vrf_id_t vrf_id,
is_anycast_mac ? "Enable" : "Disable");
}
/* set the right filter - are we using l3vni only for prefix routes? */
if (filter)
if (filter) {
SET_FLAG(bgp_vrf->vrf_flags, BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY);
/*
* VNI_FLAG_USE_TWO_LABELS flag for linked L2VNIs should not be
* set before linking vrf to L3VNI. Thus, no need to clear
* that explicitly.
*/
} else {
UNSET_FLAG(bgp_vrf->vrf_flags,
BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY);
for (ALL_LIST_ELEMENTS_RO(bgp_vrf->l2vnis, node, vpn)) {
if (!CHECK_FLAG(vpn->flags, VNI_FLAG_USE_TWO_LABELS)) {
/*
* If we are flapping VNI_FLAG_USE_TWO_LABELS
* flag, update all MACIP routes in this VNI
*/
SET_FLAG(vpn->flags, VNI_FLAG_USE_TWO_LABELS);
update_all_type2_routes(bgp_evpn, vpn);
}
}
}
/* Map auto derive or configured RTs */
if (!CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VRF_IMPORT_RT_CFGD))
evpn_auto_rt_import_add_for_vrf(bgp_vrf);

View File

@ -270,8 +270,12 @@ static inline void bgpevpn_link_to_l3vni(struct bgpevpn *vpn)
vpn->bgp_vrf = bgp_lock(bgp_vrf);
listnode_add_sort(bgp_vrf->l2vnis, vpn);
/* check if we are advertising two labels for this vpn */
if (!CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY))
/*
* If L3VNI is configured,
* check if we are advertising two labels for this vpn
*/
if (bgp_vrf->l3vni &&
!CHECK_FLAG(bgp_vrf->vrf_flags, BGP_VRF_L3VNI_PREFIX_ROUTES_ONLY))
SET_FLAG(vpn->flags, VNI_FLAG_USE_TWO_LABELS);
}