auth-gen-token: Generate an auth-token per client

auth-gen-token: Generate an auth-token per client

When --auth-gen-token is used a random token key is generated for
each client after a successful user/password authentication.  This
token is expected to be returned in the password field on the
following authentications.

The token is 256 bits long and BASE64 encoded before it is stored.

  v2 - Fix Doxygen comment typo
     - Don't exceed 80 chars line length

Signed-off-by: David Sommerseth <davids@openvpn.net>
Acked-by: Steffan Karger <steffan@karger.me>
Message-Id: <1477684124-26083-4-git-send-email-davids@openvpn.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg12820.html