Fixed default behavior (route_link_local=no) in clients.conf

What?

This PR sets the default behavior to route_link_local=no. It affects how call_up and call_down scripts are being run.

The default value of route_link_local option is no when used in [prefix_] definition. However, for statically configured clients in client.conf, default value was yes and it's confusing.

Why?

It's always reasonable for boolean config options to default to false when an option isn't declared.

Steps to reproduce

Have following in clients.conf:

[client1]
hostname = client1
mac = 08:00:27:3e:9b:23
class = valid_client
address = 3001:db8::192:168:200:100
prefix = 3001:db9:1234:5000::/54

and dhcpy6d.conf

[class_valid_client]
advertise = addresses, prefixes
call_up = ip -6 route add $prefix$/$length$ via $router$ dev enp0s8
call_down = ip -6 route delete $prefix$/$length$ via $router$ dev enp0s8

Let the client solicit for the new configuration. See logs.

Before:

2021-03-18 15:55:48,022 dhcpy6d INFO Called 'ip -6 route add 3001:0db9:1234:5000:0000:0000:0000:0000/54 via fe80:0000:0000:0000:0a00:27ff:fe3e:9b23 dev enp0s8' to modify route

⚠️ The via address is link-local.

After

2021-03-18 15:56:00,443 dhcpy6d INFO Called 'ip -6 route add 3001:0db9:1234:5000:0000:0000:0000:0000/54 via 3001:0db8:0000:0000:0192:0168:0200:0100 dev enp0s8' to modify route

✅ The via address is global.

HenriWahl / dhcpy6d