diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index 0d08af5..efdc8f3 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -140,7 +140,7 @@
 			    uint16_t nsei);
 const struct osmo_sockaddr *gprs_ns2_nse_sns_remote(struct gprs_ns2_nse *nse);
 
-const struct osmo_sockaddr *gprs_ns2_ip_vc_remote(struct gprs_ns2_vc *nsvc);
+const struct osmo_sockaddr *gprs_ns2_ip_vc_remote(const struct gprs_ns2_vc *nsvc);
 const struct osmo_sockaddr *gprs_ns2_ip_vc_local(const struct gprs_ns2_vc *nsvc);
 const struct osmo_sockaddr *gprs_ns2_ip_bind_sockaddr(struct gprs_ns2_vc_bind *bind);
 int gprs_ns2_is_ip_bind(struct gprs_ns2_vc_bind *bind);