Re: We do not need pg_promote_v4_to_v6_addr/mask

On 02/16/2015 09:07 PM, Tom Lane wrote:
> I wrote:
>> We have some code in the server that attempts to match IPv4 address
>> entries in pg_hba.conf to incoming connections that are in IPv6 protocol
>> but have addresses in the range ::ffff:xxxx:xxxx (the IPv4-in-IPv6
>> subrange).  As revealed by today's bug report from Hugo Osvaldo Barrera,
>> this code has been broken since commit f3aec2c7f51904e7 (shipped in 9.0),
>> as a result of sloppiness with a memcpy() source address.  How is it that
>> nobody noticed?
> BTW, a bit of digging in the git logs and mail archives says that the code
> in question was originally added in 7.4 (commit 3c9bb8886df7d56a), in
> response to this discussion:
> http://www.postgresql.org/message-id/flat/200309012156.05874.t.maekitalo@epgmbh.de
>
> So back in 2003 there were Linux boxes that actively transformed IPv4
> connection addresses to ::ffff:xxxx:xxxx format.  Current Linux behavior
> is the exact opposite: even if you try to say ::ffff:xxxx:xxxx in a
> connection request, IPv4 is what comes out the other end.  I find the same
> on current OS X btw.  So I'm definitely now of the opinion that this is a
> workaround for a long-deceased Linux kernel bug, and not something we need
> to continue^X^X^Xresume supporting.
>
>             

Wow, talk about a walk down memory lane. Apparently that thread 
triggered my rewrite of initdb - I'd totally forgotten that.

The proposed course sounds reasonable enough.

cheers

andrew