[Ddclient-support] Support for IPv6 (patch)

[Eduardo T. <etr...@gm...>]

Hi,

I wrote a little patch for 3.8.1 to support IPv6 on the two services I 
know that can handle it.  Both dyndns and freedns automatically 
recognize the type of address being passed to them and use it to update 
the A or the AAAA record.

I added the "usev6" variable, that works exactly as the "use" one.  So, 
if you are using dynds and change use/usev6 on your existing definition 
*and* you have a global IPv6 address you're all set.

For "usev6" only the "ip" and "if" strategies are implemented and the 
"if" one uses "ip -6 addr list" instead of "ifconfig" because I find it 
easier to parse and it doesn't need root privileges (Debian box).

So far the patch works for dyndns without problems, for an IPv6-only 
host (well, it does have IPv4 but its a private address, the IPv6 
address is public and comes from miredo/teredo).

Since the program hashes the hosts on the dynamic domain, it is not 
possible to update IPv4 and IPv6 on the same service with the same 
configuration file.  I'm not that fluent in perl so I guess it's better 
for the actual programmers to sort that one out.

Freedns forces you to have an IPv4 record that is used to build the 
update url.  The IPv6 update on that url works but the DNS servers can 
take a long time to notice it.  It's tricky.

I hope it helps somebody, it took me a while to figure it out.

Eduardo.