Create new 'gprs-sgsn' branch on top of 'gprs-conf'

This branch contains the partial SGSN/GGSN implementation that
was originally developed as part of the gprs branch.
diff --git a/openbsc/include/openbsc/gprs_llc.h b/openbsc/include/openbsc/gprs_llc.h
new file mode 100644
index 0000000..cd4e215
--- /dev/null
+++ b/openbsc/include/openbsc/gprs_llc.h
@@ -0,0 +1,20 @@
+#ifndef _GPRS_LLC_H
+#define _GPRS_LLC_H
+
+/* Section 4.7 LLC Layer Structure */
+enum gprs_llc_sapi {
+	GPRS_SAPI_GMM		= 1,
+	GPRS_SAPI_TOM2		= 2,
+	GPRS_SAPI_SNDCP3	= 3,
+	GPRS_SAPI_SNDCP5	= 5,
+	GPRS_SAPI_SMS		= 7,
+	GPRS_SAPI_TOM8		= 8,
+	GPRS_SAPI_SNDCP9	= 9,
+	GPRS_SAPI_SNDCP11	= 11,
+};
+
+
+int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv);
+int gprs_llc_tx_ui(struct msgb *msg, u_int8_t sapi, int command);
+
+#endif