The server protocol for this is
:<uid> ENCAP * CERTFP :<40 hex chars>
both in new user introductions and in burst.
As in oftc-hybrid, only the user themselves and opers can see the certfp.
Displaying the certfp on connect seems unnecessary to me,
the user can whois themselves if needed.
This lets a user connect with a client certificate, and
passes the certificate's fingerprint to ircd, which
currently just notices it to the user.
A new ssld->ircd message 'F' is used to pass on the
fingerprint.
This is only for OpenSSL for now, not GNUTLS.
When ssld reports a connection closure because of
"Remote host closed the connection" and the connection
is any server or a registered client, try a
read_packet() on the client.
This should mainly help LIBRB_USE_IOTYPE=poll which
iterates over the ready file descriptors in numerical
order, processing the ssld control connection before the
closing data connection.