[dhcpv6_relay] Fix DHCPv6 Relay config CLI to update DHCP_RELAY table

[praveen-ramamoorthi]

Why I did it

Recently, DHCPv6 Relay DB table is changed from VLAN to DHCP_RELAY. The dhcp6relay process is spawned with the data fetched from this new table . The show CLIs were updated , but config CLIs were not updated to write to new table and still updated old VLAN table. Hence the DHCPv6 Relay was not working with CLI configurations.

How I did it

The config CLI script is modified to update new table DHCP_RELAY. The UT scripts are modified to test new table.

How to verify it

Configure DHCPv6 Relay address for vlan using CLI and check if the config is updated in DHCP_RELAY table and verify if DHCPv6 Relay process is started for that vlan.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211

Description for the changelog

Fixed configuration CLI for DHCPv6 Relay to update data in DHCP_RELAY table.

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: praveen-ramamoorthi / name: Praveen Ramamoorthi (34aa355)

[praveen-ramamoorthi]

@kellyyeh Can you please review this fix?

[vivekrnv]

I don't think we should just redirect the dhcpv6_servers field to DHCP_RELAY table. We're also leaving out rfc6939_support field.

i instead think we should update the VLAN cli to reject adding dhcpv6 config and just load the config with config load and restart the service. Related issue on that: #12954. @kellyyeh , @yxieca what do you think

[kellyyeh]

I don't think we should just redirect the dhcpv6_servers field to DHCP_RELAY table. We're also leaving out rfc6939_support field.

i instead think we should update the VLAN cli to reject adding dhcpv6 config and just load the config with config load and restart the service. Related issue on that: #12954. @kellyyeh , @yxieca what do you think

@vivekrnv Agreed. Config add/del was a feature for VLAN table and we did not have plan to use config cli to update DHCP_RELAY. dhcp6relay does not support dynamic change in DHCP_RELAY table yet, so let's stick with config load and restart service only

[praveen-ramamoorthi]

@vivekrnv @kellyyeh - This PR implements config load + service restart in Click command & thus avoid manual config load + service restart sequence. For #12954, I would prefer fixing the issue (update in proper redis tables) rather than rejecting the config.

From command definition perspective, VLAN related configurations are grouped under "config vlan <>" tree. This does not mean that all such configurations are stored in single redis DB table. For example, "config vlan member <>" & "config vlan proxy_arp <>" are being updated into VLAN_MEMBER & VLAN_INTERFACE tables respectively.

Regarding "rfc6939_support", no Click command is available yet which shall be treated as new command enhancement.