libmsc: ran_iu_make_security_mode_command(): clarify UIA mask
Change-Id: I7535d5ede5b22c61575a16d15927598e6137392a
diff --git a/src/libmsc/ran_msg_iu.c b/src/libmsc/ran_msg_iu.c
index 6705ab8..cf57d35 100644
--- a/src/libmsc/ran_msg_iu.c
+++ b/src/libmsc/ran_msg_iu.c
@@ -375,6 +375,8 @@
static struct msgb *ran_iu_make_security_mode_command(struct osmo_fsm_inst *caller_fi,
const struct ran_cipher_mode_command *cm)
{
+ /* TODO: make the choice of available UIA algorithms configurable */
+ const uint8_t uia_mask = (1 << OSMO_UTRAN_UIA1) | (1 << OSMO_UTRAN_UIA2);
bool use_encryption = cm->utran.uea_encryption_mask > (1 << OSMO_UTRAN_UEA0);
LOG_RAN_IU_ENC(caller_fi, LOGL_DEBUG, "Tx RANAP SECURITY MODE COMMAND to RNC, IK=%s, CK=%s\n",
@@ -384,7 +386,9 @@
* in the case of A5? */
return ranap_new_msg_sec_mod_cmd2(cm->vec->ik,
use_encryption ? cm->vec->ck : NULL,
- RANAP_KeyStatus_new, 0x06, cm->utran.uea_encryption_mask);
+ RANAP_KeyStatus_new,
+ (uia_mask << 1), /* API treats LSB as UIA0 */
+ cm->utran.uea_encryption_mask);
}