dhcp: T3316: Support hostname, DUID and MAC address in reservation

[indrajitr]

Change Summary

Reinstate support for hostname in DHCP reservation. Having hostname in allows for server-side assignment of hostname. This is useful for static lookup of hostname.

Additionally, support using either of DUID or MAC address for reservation. While MAC address is typically used for IPv4, and DUID is typically used for IPv6, both can be used for both cases in Kea.

For details, see:

• https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp4-srv.html#host-reservations-in-dhcpv4
• https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html#host-reservations-in-dhcpv6
• https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html#mac-hardware-addresses-in-dhcpv6

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T3316

Related PR(s)

• dhcp: T5846: Refactor and simplify DUID definition #2664

Component(s) name

dhcp-server, dhcpv6-server

Proposed changes

How to test

Smoketest result

vyos@v15-1221:~$ /usr/libexec/vyos/tests/smoke/cli/test_service_dhcp-server.py 
test_dhcp_exclude_in_range (__main__.TestServiceDHCPServer.test_dhcp_exclude_in_range) ... ok
test_dhcp_exclude_not_in_range (__main__.TestServiceDHCPServer.test_dhcp_exclude_not_in_range) ... ok
test_dhcp_failover (__main__.TestServiceDHCPServer.test_dhcp_failover) ... 
No DHCP address range or active static-mapping configured within shared-
network "FAILOVER, 192.0.2.0/25"!

ok
test_dhcp_multiple_pools (__main__.TestServiceDHCPServer.test_dhcp_multiple_pools) ... ok
test_dhcp_relay_server (__main__.TestServiceDHCPServer.test_dhcp_relay_server) ... ok
test_dhcp_single_pool_options (__main__.TestServiceDHCPServer.test_dhcp_single_pool_options) ... 
No DHCP address range or active static-mapping configured within shared-
network "SMOKE-0815, 192.0.2.0/25"!

ok
test_dhcp_single_pool_range (__main__.TestServiceDHCPServer.test_dhcp_single_pool_range) ... 
No DHCP address range or active static-mapping configured within shared-
network "SMOKE-1, 192.0.2.0/25"!

ok
test_dhcp_single_pool_static_mapping (__main__.TestServiceDHCPServer.test_dhcp_single_pool_static_mapping) ... 
No DHCP address range or active static-mapping configured within shared-
network "SMOKE-2, 192.0.2.0/25"!


Either MAC address or Client identifier (DUID) is required for static
mapping "client1" within shared-network "SMOKE-2, 192.0.2.0/25"!

ok

----------------------------------------------------------------------
Ran 8 tests in 198.886s

OK
vyos@v15-1221:~$ /usr/libexec/vyos/tests/smoke/cli/test_service_dhcpv6-server.py 
test_global_nameserver (__main__.TestServiceDHCPv6Server.test_global_nameserver) ... ok
test_prefix_delegation (__main__.TestServiceDHCPv6Server.test_prefix_delegation) ... ok
test_single_pool (__main__.TestServiceDHCPv6Server.test_single_pool) ... 
Either MAC address or Client identifier (DUID) is required for static
mapping "client1" within shared-network "SMOKE-1, 2001:db8:f00::/64"!

ok

----------------------------------------------------------------------
Ran 3 tests in 85.947s

OK

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[c-po]

We already have this:

    <leafNode name="duid">
      <properties>
        <help>DHCP unique identifier (DUID) to be sent by dhcpv6 client</help>
        <valueHelp>
          <format>duid</format>
          <description>DHCP unique identifier (DUID)</description>
        </valueHelp>
        <constraint>
          <validator name="ipv6-duid"/>
        </constraint>
      </properties>
    </leafNode>

in interface/dhcpv6-options.xml.i - maybe rename this node here and make it a common XML include block?

[indrajitr]

I have a follow-up PR lined up for refactoring the XML blocks that include this one.
Couple of reasons I held back is because:

1. the regex pattern for ipv6-duid validator is slightly different. It won't match aa:bb:c:d, but current identifier node honors that. I need to have migration take care of that.
2. ipv6-duid is a full Python script. I think we can convert that into a simple shell script having ${vyos_libexec_dir}/validate-value --regex ....

I plan to tackle them together (including migration).

[indrajitr]

I'm adding migration from identifier to duid in this PR instead of a followup PR. Converting this to draft till migration scripts are ready.

[indrajitr]

This needs to be applied after #2664.