[PATCH] Patch to make pg_hba.conf handle virtualhost access control and samehost keyword

Hi
This patch againsts postgresql 7.1.2 allows you to control access based on the
virtual host address only (virtualhost access type), or both the remote
address and the local address (connection access type).

For example:

connection all 192.168.42.0 255.255.255.0 192.168.1.42 255.255.255.255 trust

This patch also allows keyword "samehost", similar to "sameuser" but for
hosts.

For example:

virtualhost sameuser samehost.sql.domain.com 255.255.255.255 trust

will prevent you from doing 1 entry per user, all you need is a
(local) dns entry for each host (user foo needs foo.sql.domain.com)
If the dns entry is not found, the line is dropped, so rejecting with
samehost is not a good idea for the moment.

Any comments are welcome.
Please not that I'm not on the list.

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Damien Clermonte