smtpd: use mx name for sni

[Eric Faurot]

As spotted by krw@, the mta should use the mx hostname for sni, not
the reverse dns for the peer address.

Eric.


Index: mta_session.c
===================================================================
RCS file: /cvs/src/usr.sbin/smtpd/mta_session.c,v
retrieving revision 1.139
diff -u -p -r1.139 mta_session.c
--- mta_session.c       5 Mar 2021 12:37:32 -0000       1.139
+++ mta_session.c       7 Mar 2021 20:18:42 -0000
@@ -1596,7 +1596,7 @@ mta_tls_init(struct mta_session *s)
                return;
        }
 
-       io_connect_tls(s->io, tls, s->route->dst->ptrname);
+       io_connect_tls(s->io, tls, s->mxname);
 }
 
 static void