+#ifdef HAVE_TLS
+static int
+ldap_back_start_tls(
+ LDAP *ld,
+ int protocol,
+ int *is_tls,
+ const char *url,
+ unsigned flags,
+ const char **text )
+{
+ int rc = LDAP_SUCCESS;
+ struct ldapinfo li;
+
+ /* this is ridicolous... */
+ li.flags = flags;
+
+ /* start TLS ("tls-[try-]{start,propagate}" statements) */
+ if ( ( LDAP_BACK_USE_TLS( &li ) || ( *is_tls && LDAP_BACK_PROPAGATE_TLS( &li ) ) )
+ && !ldap_is_ldaps_url( url ) )
+ {
+#ifdef SLAP_STARTTLS_ASYNCHRONOUS
+ /*
+ * use asynchronous StartTLS
+ * in case, chase referral (not implemented yet)
+ */
+ int msgid;
+
+ if ( protocol == 0 ) {
+ ldap_get_option( ld, LDAP_OPT_PROTOCOL_VERSION,
+ (void *)&protocol );
+ }
+
+ if ( protocol < LDAP_VERSION3 ) {
+ protocol = LDAP_VERSION3;
+ /* Set LDAP version */
+ ldap_set_option( ld, LDAP_OPT_PROTOCOL_VERSION,
+ (const void *)&protocol );
+ }
+
+ rc = ldap_start_tls( ld, NULL, NULL, &msgid );
+ if ( rc == LDAP_SUCCESS ) {
+ LDAPMessage *res = NULL;
+ int retries = 1;
+ struct timeval tv = { 0, 0 };
+
+retry:;
+ rc = ldap_result( ld, msgid, LDAP_MSG_ALL, &tv, &res );
+ if ( rc < 0 ) {
+ rc = LDAP_OTHER;
+
+ } else if ( rc == 0 ) {
+ if ( retries ) {
+ retries--;
+ tv.tv_sec = 0;
+ tv.tv_usec = 100000;
+ goto retry;
+ }
+ rc = LDAP_OTHER;
+
+ } else if ( rc == LDAP_RES_EXTENDED ) {
+ struct berval *data = NULL;
+
+ rc = ldap_parse_extended_result( ld, res,
+ NULL, &data, 0 );
+ if ( rc == LDAP_SUCCESS ) {
+ rc = ldap_result2error( ld, res, 1 );
+ res = NULL;
+
+ /* FIXME: in case a referral
+ * is returned, should we try
+ * using it instead of the
+ * configured URI? */
+ if ( rc == LDAP_SUCCESS ) {
+ rc = ldap_install_tls( ld );
+
+ } else if ( rc == LDAP_REFERRAL ) {
+ rc = LDAP_OTHER;
+ *text = "unwilling to chase referral returned by Start TLS exop";
+ }
+
+ if ( data ) {
+ if ( data->bv_val ) {
+ ber_memfree( data->bv_val );
+ }
+ ber_memfree( data );
+ }
+ }
+
+ } else {
+ rc = LDAP_OTHER;
+ }
+
+ if ( res != NULL ) {
+ ldap_msgfree( res );
+ }
+ }
+#else /* ! SLAP_STARTTLS_ASYNCHRONOUS */
+ /*
+ * use synchronous StartTLS
+ */
+ rc = ldap_start_tls_s( ld, NULL, NULL );
+#endif /* ! SLAP_STARTTLS_ASYNCHRONOUS */
+
+ /* if StartTLS is requested, only attempt it if the URL
+ * is not "ldaps://"; this may occur not only in case
+ * of misconfiguration, but also when used in the chain
+ * overlay, where the "uri" can be parsed out of a referral */
+ switch ( rc ) {
+ case LDAP_SUCCESS:
+ *is_tls = 1;
+ break;
+
+ case LDAP_SERVER_DOWN:
+ break;
+
+ default:
+ if ( LDAP_BACK_TLS_CRITICAL( &li ) ) {
+ *text = "could not start TLS";
+ break;
+ }
+
+ /* in case Start TLS is not critical */
+ *is_tls = 0;
+ rc = LDAP_SUCCESS;
+ break;
+ }
+
+ } else {
+ *is_tls = 0;
+ }
+
+ return rc;
+}
+#endif /* HAVE_TLS */
+