[Dovecot] sendmail smtp auth using client socket

Hi list

I searched the net, but could not find something related.

Is it possible to export the client socket to sendmail for smtp auth?
What would be the sendmail.mc configuration for this?

#client {
   # The client socket is generally safe to export to everyone. Typical use
   # is to export it to your SMTP server so it can do SMTP AUTH lookups
   # using it.
   #path = /var/spool/postfix/private/auth
   #mode = 0660
   #user = postfix
   #group = postfix
 #}

It can also be the other way round: can Dovecot use Cyrus SASL for
user authentication?

I need to use sendmail, ip based solutions like pop-before-smtp or
poprelay are not an option.

Thanks, Mike