add support for client authentication via certificates

The SASL EXTERNAL method is implemented to make this possible.

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>

src/tls.h

@@ -27,6 +27,9 @@ void tls_shutdown(void);
 tls_t *tls_new(xmpp_conn_t *conn);
 void tls_free(tls_t *tls);
 
+char *tls_id_on_xmppaddr(xmpp_conn_t *conn, unsigned int n);
+unsigned int tls_id_on_xmppaddr_num(xmpp_conn_t *conn);
+
 int tls_set_credentials(tls_t *tls, const char *cafilename);
 
 int tls_start(tls_t *tls);