diff --git a/include/openbsc/gsm_04_08.h b/include/openbsc/gsm_04_08.h
index 23a637a..8265219 100644
--- a/include/openbsc/gsm_04_08.h
+++ b/include/openbsc/gsm_04_08.h
@@ -392,6 +392,7 @@
 enum gsm_chreq_reason_t get_reason_by_chreq(struct gsm_bts *bts, u_int8_t ra);
 
 int gsm48_tx_mm_info(struct gsm_lchan *lchan);
+struct msgb *gsm48_msgb_alloc(void);
 
 
 #endif