Sub-interface created using short parent interface name failed to bind to VRF

[Hedgehog-Guru]

Description

Sub-interface created using short parent interface name failed to bind to VRF. Long name form works OK.

Steps to reproduce the issue:

1. Create any VRF
2. Create any subinterface using short form
3. Try to bind subinterface to VRF
4. Check subinterface status

Describe the results you received:

Sub-interface disappear from "show subinterfaces status" output. Linux interface is missed

Describe the results you expected:

Normal bind like any other interface

Output of show version:

root@qa-eth-vt03-4-3700v:/home/admin# show ver

SONiC Software Version: SONiC.202111_rc_11_20220503.1-dcd5b93ce_Internal
Distribution: Debian 11.3
Kernel: 5.10.0-8-2-amd64
Build commit: dcd5b93ce
Build date: Wed May  4 16:14:17 UTC 2022
Built by: sw-r2d2-bot@r-build-sonic02-006

Platform: x86_64-mlnx_msn3700-r0
HwSKU: ACS-MSN3700
ASIC: mellanox
ASIC Count: 1
Serial Number: MT1932X22252
Model Number: MSN3700-VS2F
Hardware Revision: A1
Uptime: 18:29:35 up 15 min,  1 user,  load average: 0.29, 0.26, 0.20

Output of show techsupport:

attached

Additional information you deem important (e.g. issue happens only occasionally):

root@qa-eth-vt03-4-3700v:/home/admin# config subinterface add Ethernet48.10 10
root@qa-eth-vt03-4-3700v:/home/admin# config subinterface add Eth48.11 11
root@qa-eth-vt03-4-3700v:/home/admin# config vrf add Vrf_RED
root@qa-eth-vt03-4-3700v:/home/admin# show subinterfaces status
  Sub port interface    Speed    MTU    Vlan    Admin                  Type
--------------------  -------  -----  ------  -------  --------------------
            Eth48.11     200G   9100      11     down  802.1q-encapsulation
       Ethernet48.10     200G   9100      10     down  802.1q-encapsulation
root@qa-eth-vt03-4-3700v:/home/admin# ip link show Ethernet48.10
71: Ethernet48.10@Ethernet48: <BROADCAST,MULTICAST,M-DOWN> mtu 9100 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether b8:59:9f:a8:e2:00 brd ff:ff:ff:ff:ff:ff
root@qa-eth-vt03-4-3700v:/home/admin# ip link show Eth48.11
72: Eth48.11@Ethernet48: <BROADCAST,MULTICAST,M-DOWN> mtu 9100 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether b8:59:9f:a8:e2:00 brd ff:ff:ff:ff:ff:ff
root@qa-eth-vt03-4-3700v:/home/admin# config interface vrf bind Ethernet48.10 Vrf_RED
root@qa-eth-vt03-4-3700v:/home/admin# show subinterfaces status
  Sub port interface    Speed    MTU    Vlan    Admin                  Type
--------------------  -------  -----  ------  -------  --------------------
            Eth48.11     200G   9100      11     down  802.1q-encapsulation
       Ethernet48.10     200G   9100      10     down  802.1q-encapsulation
root@qa-eth-vt03-4-3700v:/home/admin# show vrf
VRF      Interfaces
-------  ------------
Vrf_RED
root@qa-eth-vt03-4-3700v:/home/admin# config interface vrf bind Eth48.11 Vrf_RED
root@qa-eth-vt03-4-3700v:/home/admin# show subinterfaces status
  Sub port interface    Speed    MTU    Vlan    Admin                  Type
--------------------  -------  -----  ------  -------  --------------------
       Ethernet48.10     200G   9100      10     down  802.1q-encapsulation
root@qa-eth-vt03-4-3700v:/home/admin# show vrf
VRF      Interfaces
-------  ------------
Vrf_RED
root@qa-eth-vt03-4-3700v:/home/admin# ip link show Ethernet48.10
74: Ethernet48.10@Ethernet48: <BROADCAST,MULTICAST,M-DOWN> mtu 9100 qdisc noop master Vrf_RED state DOWN mode DEFAULT group default qlen 1000
    link/ether b8:59:9f:a8:e2:00 brd ff:ff:ff:ff:ff:ff
root@qa-eth-vt03-4-3700v:/home/admin# ip link show Eth48.11
Device "Eth48.11" does not exist.
root@qa-eth-vt03-4-3700v:/home/admin# 

sonic_dump_qa-eth-vt03-4-3700v_20220510_183041.tar.gz

[dgsudharsan]

@preetham-singh @adyeung @prsunny FYI

[preetham-singh]

From captured dump, short name subinterface Eth48.11 fields are being overwritten with vrf binding information after vrf bind operation. Due to this vlan encap information is getting deleted after vrf binding.
In contrast, long name subinterfaces vlan encap is derived from subinterface index in intfmgrd, hence the issue not observed for long name subinterfaces.
I will fix this by updating vrf binding click CLI.

From the config dump captured:
"VLAN_SUB_INTERFACE|Eth48.11": {
"expireat": 1652196677.6583672,
"ttl": -0.001,
"type": "hash",
"value": {
"vrf_name": "Vrf_RED" <<< Vlan field,value are overwritten with vrf information causing subinterface deletion. Fix is add vrf information instead of overwriting.
}
},

[adyeung]

Fix available in sonic-net/sonic-utilities#2211

[adyeung]

Close ticket, fix has merged