diff --git a/openbsc/src/nat/Makefile.am b/openbsc/src/nat/Makefile.am
index 2f37f5c..c7c4b0e 100644
--- a/openbsc/src/nat/Makefile.am
+++ b/openbsc/src/nat/Makefile.am
@@ -6,7 +6,7 @@
 
 
 bsc_nat_SOURCES = bsc_filter.c bsc_mgcp_utils.c bsc_nat.c bsc_nat_utils.c \
-		  bsc_nat_vty.c bsc_sccp.c \
+		  bsc_nat_vty.c bsc_sccp.c bsc_ussd.c \
 		$(top_srcdir)/src/debug.c $(top_srcdir)/src/bsc_msc.c
 bsc_nat_LDADD = $(top_builddir)/src/libvty.a \
 		$(top_builddir)/src/libmgcp.a $(top_builddir)/src/libbsc.a \
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index b82c4ef..515278c 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -854,12 +854,19 @@
 						con = NULL;
 						goto exit2;
 					}
+
+					/* hand data to a side channel */
+					if (bsc_check_ussd(con, parsed, msg) == 1) {
+						/* we are going to take over the connection */
+						/* TODO: */
+					}
 				}
 
 				con_bsc = con->bsc;
 				con_msc = con->msc_con;
 				con_filter = con->con_local;
 			}
+
 			break;
 		case SCCP_MSG_TYPE_RLC:
 			con = patch_sccp_src_ref_to_msc(msg, parsed, bsc);
diff --git a/openbsc/src/nat/bsc_ussd.c b/openbsc/src/nat/bsc_ussd.c
new file mode 100644
index 0000000..1812cf7
--- /dev/null
+++ b/openbsc/src/nat/bsc_ussd.c
@@ -0,0 +1,32 @@
+/* USSD Filter Code */
+
+/*
+ * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010 by On-Waves
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <openbsc/bsc_nat.h>
+#include <openbsc/bsc_nat_sccp.h>
+
+
+int bsc_check_ussd(struct sccp_connections *con, struct bsc_nat_parsed *parsed,
+		   struct msgb *msg)
+{
+	return 0;
+}