diff --git a/openbsc/include/osmocom/gprs/Makefile.am b/openbsc/include/osmocom/gprs/Makefile.am
index fe5714e..66b414f 100644
--- a/openbsc/include/osmocom/gprs/Makefile.am
+++ b/openbsc/include/osmocom/gprs/Makefile.am
@@ -1,3 +1,3 @@
-libgb_HEADERS = gprs_bssgp.h gprs_ns.h gprs_ns_frgre.h
+libgb_HEADERS = gprs_bssgp.h gprs_ns.h gprs_ns_frgre.h gprs_msgb.h
 
 libgbdir = $(includedir)/osmocom/gprs
diff --git a/openbsc/include/osmocom/gprs/gprs_bssgp.h b/openbsc/include/osmocom/gprs/gprs_bssgp.h
index bfc7d33..9970a51 100644
--- a/openbsc/include/osmocom/gprs/gprs_bssgp.h
+++ b/openbsc/include/osmocom/gprs/gprs_bssgp.h
@@ -198,6 +198,7 @@
 
 
 #include <osmocom/gsm/tlv.h>
+#include <osmocom/gprs/gprs_msgb.h>
 
 /* BSSGP-UL-UNITDATA.ind */
 int gprs_bssgp_rcvmsg(struct msgb *msg);
diff --git a/openbsc/include/osmocom/gprs/gprs_msgb.h b/openbsc/include/osmocom/gprs/gprs_msgb.h
new file mode 100644
index 0000000..eddd888
--- /dev/null
+++ b/openbsc/include/osmocom/gprs/gprs_msgb.h
@@ -0,0 +1,30 @@
+#ifndef _LIBGB_MSGB_H
+#define _LIBGB_MSGB_H
+
+#include <stdint.h>
+/* the data structure stored in msgb->cb for libgb apps */
+struct libgb_msgb_cb {
+	unsigned char *bssgph;
+	unsigned char *llch;
+
+	/* Cell Identifier */
+	unsigned char *bssgp_cell_id;
+
+	/* Identifiers of a BTS, equal to 'struct bssgp_bts_ctx' */
+	uint16_t nsei;
+	uint16_t bvci;
+
+	/* Identifier of a MS (inside BTS), equal to 'struct sgsn_mm_ctx' */
+	uint32_t tlli;
+} __attribute__((packed));
+#define LIBGB_MSGB_CB(__msgb)	((struct libgb_msgb_cb *)&((__msgb)->cb[0]))
+#define msgb_tlli(__x)		LIBGB_MSGB_CB(__x)->tlli
+#define msgb_nsei(__x)		LIBGB_MSGB_CB(__x)->nsei
+#define msgb_bvci(__x)		LIBGB_MSGB_CB(__x)->bvci
+#define msgb_gmmh(__x)		(__x)->l3h
+#define msgb_bssgph(__x)	LIBGB_MSGB_CB(__x)->bssgph
+#define msgb_bssgp_len(__x)	((__x)->tail - (uint8_t *)msgb_bssgph(__x))
+#define msgb_bcid(__x)		LIBGB_MSGB_CB(__x)->bssgp_cell_id
+#define msgb_llch(__x)		LIBGB_MSGB_CB(__x)->llch
+
+#endif
diff --git a/openbsc/include/osmocom/gprs/gprs_ns.h b/openbsc/include/osmocom/gprs/gprs_ns.h
index 7045d84..cfc2e90 100644
--- a/openbsc/include/osmocom/gprs/gprs_ns.h
+++ b/openbsc/include/osmocom/gprs/gprs_ns.h
@@ -88,6 +88,7 @@
 #include <osmocom/core/msgb.h>
 #include <osmocom/core/timer.h>
 #include <osmocom/core/select.h>
+#include <osmocom/gprs/gprs_msgb.h>
 
 #define NS_TIMERS_COUNT 7
 #define NS_TIMERS "(tns-block|tns-block-retries|tns-reset|tns-reset-retries|tns-test|tns-alive|tns-alive-retries)"