GTlsClientConnection and STARTTLS

[Eric Gregory <eric yorba org>]

I'm running into some trouble trying to add STARTTLS support to an GLib-based SMTP client.  (Hopefully I'm sending this to the right place.)

According to the docs for g_tls_connection_handshake(), a handshake will occur automatically after STARTTLS is issued.  That doesn't make a whole lot of sense to me, since (as far as I can tell) you can't use a GTlsClientConnection for a plain, non-encrypted connection.

I would expect that I'd have to connect in the plain with a normal GSocketClient, issue a STARTTLS, and finally wrap the GSocketConnection with a GTlsClientConnection and do a handshake.  But that isn't working for me either; according to Wireshark I'm getting an Encrypted Alert with an invalid message.

So my question is: is the doc correct?  If so, how do I go about using GTlsClientConnection with STARTTLS?  If not, is GLib capable of handling STARTTLS, or do I need to use GnuTLS directly?

Thanks,
 - Eric