dhcpcd-discuss

On 13/12/2019 07:27, andrey@xxxxxxxxxxxx wrote:
> Hi Ron,
>
>  > without thinking how to integrate it with dhcpcd. I mean, start by 
> writing the commands
>  > assuming it has all the information it needs. You might use pseudo 
> values like
>
>  > ip route I_WILL_SOMEHOW_FIND_THE_IP_LATER
> that’s not the point, it’s obvious:
>
> /usr/bin/ip -6 route add default via GATEWAY dev WAN table main mtu MTU 
> expires EXPIRATION
>
> But, ipv6-route added this way needs all those parameters. For example: 
> routes communicated by ROUTERADVERTISMENT message (IPv6 NDP) have 
> explicitely defiled lifetime, typically 1800 sec. How to get the 
> lifetime from RA? Are routes communicated by DHCPv6 response also 
> expiring? How to bring those two sources of routing information 
> together? DHCPCD is already managing it in code properly (hopefully), 
> why to reconstruct this logic in the shell script?

dhcpcd -dB6T

xennet0: Router Advertisement from fe80::1
xennet0: executing `/libexec/dhcpcd-run-hooks' TEST
interface=xennet0
pid=2563
protocol=ra
reason=TEST
ifcarrier=up
ifflags=4294936643
ifmtu=1500
ifwireless=0
nd1_acquired=1179202
nd1_dnssl1_lifetime=900
nd1_dnssl1_search=marples.name
nd1_from=fe80::1
nd1_mtu=1480
nd1_now=1179202
nd1_prefix_information1_flags=LA
nd1_prefix_information1_length=64
nd1_prefix_information1_pltime=0
nd1_prefix_information1_prefix=fd73:7808:1015::
nd1_prefix_information1_vltime=0
nd1_prefix_information2_flags=L
nd1_prefix_information2_length=64
nd1_prefix_information2_pltime=1200
nd1_prefix_information2_prefix=2001:470:690c:1::
nd1_prefix_information2_vltime=1800
nd1_prefix_information3_flags=L
nd1_prefix_information3_length=64
nd1_prefix_information3_pltime=1200
nd1_prefix_information3_prefix=2001:470:690c:2::
nd1_prefix_information3_vltime=1800
nd1_prefix_information4_flags=L
nd1_prefix_information4_length=64
nd1_prefix_information4_pltime=1200
nd1_prefix_information4_prefix=2001:470:690c:3::
nd1_prefix_information4_vltime=1800
nd1_rdnss1_lifetime=900
nd1_rdnss1_servers='fe80::1%xennet0'
nd1_source_address=f20ba43f5ef7

Basically the whole RA is converted to env vars.

> Indeed, I’m software developer so I know how to create a script. I’d 
> surely manage it finaly but it would take plety of iterations to fugure 
> out all undocumented details (or to find it in DHCPCD source code).

The man pages should be document enough.
For detailed env vars you get, look at dhcpcd-definitions.conf.
It's pretty easy to convert any messages once you look at this file :)

Roy