Hi,
I have been working on improving IPv6 support of ldirectord
for a few weeks. I would like to hear your opinion or ideas
about how to write ldirectord.conf.
Q1. Should ldirectord support an IPv6 hostname in ldirectord.conf?
A manual of ldirectord says that a hostname can be written
in "virtual", "real", "fallback" and so on. Current
implementation of ldirectord handles the hostname as only
IPv4. It partially supports IPv6, and can write only IPv6
addresses. But it does not have a way to write a hostname as
IPv6. Because there is no way to distinguish between IPv4
and IPv6. Should ldirectord support an IPv6 hostname in
ldirectord.conf?
Q2. If the answer of Q1 is yes, how do you want to write?
[Candidate 1] Adding a new keyword like a "ipversion".
A default value of "ipversion" is 4 (IPv4).
fallback=fallback.example.com
fallback6=fallback.example.com
virtual=virtual.example.com:daytime
real=real1.example.com:daytime gate
real=10.10.10.10:daytime gate
virtual=virtual.example.com:daytime
ipversion=6
real=real1.example.com:daytime gate
real=[2001:db8::10]:daytime gate
This way cannot handle a global "fallback" variable. We must
have a way to distinguish between IPv4 and IPv6 when a
hostname is specified in the global "fallback" variable. To
achieve this, there is a way to add a new variable of
"fallback6". Any other good ideas?
[Candidate 2] Adding new keywords of "virtual6" and
"fallback6".
"virtual6" is an IPv6 version of "virtual". If a hostname
and an IP address are specified in the "virtual6" line and
in its section, they are treated as an IPv6 address and the
hostname will be resolved into an IPv6 address.
"fallback6" is just a global variable. It cannot be
specified in a virtual section. If no "fallback" in a
"virtual6" section is defined, the variable of "fallback6"
will be used. If "fallback" in the "virtual6" section is
defined, it is treated as an IPv6 address.
fallback=fallback.example.com
fallback6=fallback.example.com
virtual=virtual.example.com:daytime
real=real1.example.com:daytime gate
real=10.10.10.10:daytime gate
virtual6=virtual.example.com:daytime
real=real1.example.com:daytime gate
real=[2001:db8::10]:daytime gate
This way breaks a backward compatibility. Current ldirectord
can write an IPv6 address in a "virtual" line. But this way
cannot.
[Candidate 3] Completely separate IPv4 and IPv6 using
"hoge6" keywords.
Adding new keywords which denote IPv6. These keywords can
handle IPv6 only and have a name "hoge6".
fallback=fallback.example.com
fallback6=fallback.example.com
virtual=virtual.example.com:daytime
real=real1.example.com:daytime gate
real=10.10.10.10:daytime gate
virtual6=virtual.example.com:daytime
real6=real1.example.com:daytime gate
real6=[2001:db8::10]:daytime gate
fallback6=localhost:daytime
This way is very similar to [Candidate 2]. But it is
consistent and easy to read. A demerit is a bit redundant?
[Candidate 4...] Any other good ideas?
--
Sohgo Takeuchi
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