SONiC Yang model for DHCP-Relay parameters

[AkhileshSamineni]

SONiC Yang model for DHCP-Relay parameters

• What I did
  Added DHCPv6 Servers.
  Tables: VLAN, DHCP_RELAY.

• How I did it
  Defined Yang model for Relay based on Guideline doc:
  https://github.com/Azure/SONiC/blob/master/doc/mgmt/SONiC_YANG_Model_Guidelines.md

• How to verify it
  Added test cases to verify it.

Signed-off-by: Akhilesh Samineni akhilesh.samineni@broadcom.com

[dgsudharsan]

Please remove the fields for which we don't have backend support

[dgsudharsan]

@shlomibitton Please review

[AkhileshSamineni]

Please remove the fields for which we don't have backend support

@dgsudharsan Removed those fields.

[AkhileshSamineni]

@shlomibitton I still see the "dhcpv6_servers" added to VLAN table only from below configuration.

root@sonic:/home/admin# config vlan add 100
root@sonic:/home/admin# stty cols 200
root@sonic:/home/admin# config vlan member add 100 Ethernet48
root@sonic:/home/admin# config interface ip add Vlan100 10.0.0.1/24
root@sonic:/home/admin# 
root@sonic:/home/admin# config vlan dhcp_relay add 100 20.20.0.1
root@sonic:/home/admin# config vlan dhcp_relay add 100 20.20.20.20
root@sonic:/home/admin#
root@sonic:/home/admin# config interface ip add Vlan100 1001::1/24 
root@sonic:/home/admin# config vlan  dhcp_relay add 100 2001::2

root@sonic:/home/admin# show vlan brief
+-----------+--------------+------------+----------------+-------------+-----------------------+
|   VLAN ID | IP Address   | Ports      | Port Tagging   | Proxy ARP   | DHCP Helper Address   |
+===========+==============+============+================+=============+=======================+
|       100 | 10.0.0.1/24  | Ethernet48 | tagged         | disabled    | 20.20.0.1             |
|           | 1001::1/24   |            |                |             | 20.20.20.20           |
|           |              |            |                |             | 2001::2               |
+-----------+--------------+------------+----------------+-------------+-----------------------+
root@sonic:/home/admin# 
root@sonic:/home/admin# sonic-db-cli CONFIG_DB hgetall "VLAN|Vlan100"
{'dhcp_servers@': '20.20.0.1,20.20.20.20', 'vlanid': '100', 'dhcpv6_servers@': '2001::2'}
root@sonic:/home/admin#

[shlomibitton]

@AkhileshSamineni by design the DHCPv6 helpers should be configured from the configuration you mentioned.
Is there any problem with this?
https://github.com/Azure/SONiC/blob/master/doc/DHCPv6_Relay/DHCPv6_Relay_HLD.md#3-cli

[AkhileshSamineni]

@AkhileshSamineni by design the DHCPv6 helpers should be configured from the configuration you mentioned. Is there any problem with this? https://github.com/Azure/SONiC/blob/master/doc/DHCPv6_Relay/DHCPv6_Relay_HLD.md#3-cli

@shlomibitton So "dhcpv6_servers" field is getting added to "VLAN" table only right. Please review the yang model changes.

[shlomibitton]

LGTM

[lguohan]

@kellyyeh, can you review?

[kellyyeh]

We currently store dhcpv6_servers in a separate table called DHCP_RELAY, and SONiC dhcp6relay fetches dhcpv6 server addresses from this table instead of VLAN. This is the draft sonic-dhcpv6-relay.yang

module DHCP_RELAY  
    container DHCP_RELAY {  	
        list VLAN_LIST {
    		key name;
   		    leaf name {
    			type string;
  		    }
   		    leaf dhcpv6_servers {
     		    	type inet6:ip-address;
  		    }
		    leaf dhcpv6_option|rfc6939_support {
			    type bool;
		    }
        }
    }
}

And config_db schema looks like this:

DHCP_RELAY|intf-i|dhcpv6_servers: ["dhcp-server-0", "dhcp-server-1", ...., "dhcp-server-n-1"]
DHCP_RELAY|intf-i|dhcpv6_option|rfc6939_support: "true"

202106 version currently still uses ISC-DHCP which reads from VLAN table, so we need to have dhcpv6_servers in both VLAN and DHCP_RELAY

[AkhileshSamineni]

Added a new 'dhcpv6-relay' yang file changes for DHCP_RELAY table.

@kellyyeh Seeing parsing issues with leaf "dhcpv6_option|rfc6939_support", as it has '|' character.

[kellyyeh]

Can we add it as just "rfc6939_support" please?

[AkhileshSamineni]

Yes, added leaf as 'rfc6939_support'.

[AkhileshSamineni]

@lguohan Please approve and merge it.