Ipv4 addr plus port

[razvan-becheriu]

No description provided.

[razvan-becheriu]

Hi,

I have merged all the changes related to ipv4 address plus port allocation and manually tested the feature.

You can start looking over the implementation.

To test the implementation, just define a custom option in the dhclient config:

option v4-portparams code 159 = integer 32;

send v4-portparams 262144;
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
netbios-name-servers, netbios-scope, interface-mtu,
ntp-servers, v4-portparams;

Because there is no standard dhclient which requests for address plus port, I have hard-coded here the option value to be 262144 which means offset is set to 0, psid len is 4 and the actual psid is 0 (first address)

The feature currently works with the standard ipv4 client but it should be used with dhcpv4o6 client version as this feature is related to rfc7341 (DHCPv4-over-DHCPv6 (DHCP 4o6) Transport)
Please read rfc7618.

As for the server configuration, I have added 3 options for the 4o6 subnet definition:
v4-psid-offset: the offset used to calculate the port from the portparams option
v4-psid-len: the length of the psid field used to calculate the port from the portparams option
v4-excluded-psids: the excluded psid which are reserved and will not be assigned by the server

Any of these options will enable the subnet as a 4o6 subnet.
eg:

"subnet4": [
{ "subnet": "192.0.2.0/24",
"pools": [ { "pool": "192.0.2.1 - 192.0.2.200" } ],
"v4-psid-offset": 0,
"v4-psid-len": 4,
"4o6-interface": "ens4",
"v4-excluded-psids": [ 1, 5 ,7 ],
"4o6-subnet": "3001:db8:1::/64"
}
]