diff --git a/include/openbsc/gsm_04_08.h b/include/openbsc/gsm_04_08.h
index 3ef4fdb..b5eecf0 100644
--- a/include/openbsc/gsm_04_08.h
+++ b/include/openbsc/gsm_04_08.h
@@ -394,6 +394,7 @@
 int gsm48_tx_mm_info(struct gsm_lchan *lchan);
 struct msgb *gsm48_msgb_alloc(void);
 int gsm48_sendmsg(struct msgb *msg);
+int generate_mid_from_tmsi(u_int8_t *buf, u_int32_t tmsi);
 
 
 #endif