vlr: vlr_set_ciph_mode(): use vlr_subscr_security_context instead of umts_aka

Simplifies code when re-transmitting Ciphering Mode Command when using
it also for PS.

Change-Id: Ia556bc33d1cf30ef17fed2828908aa0b6b6dc8be

include/osmocom/vlr/vlr.h

@@ -488,7 +488,7 @@ void vlr_parq_cancel(struct osmo_fsm_inst *fi,
 int vlr_set_ciph_mode(struct vlr_instance *vlr,
 		      struct osmo_fsm_inst *fi,
 		      void *msc_conn_ref,
-		      bool umts_aka,
+		      enum vlr_subscr_security_context sec_ctx,
 		      bool retrieve_imeisv);
 
 bool vlr_use_umts_aka(struct osmo_auth_vector *vec, bool is_r99);

src/libvlr/vlr.c

@@ -1664,19 +1664,35 @@ void vlr_subscr_rx_ciph_res(struct vlr_subscr *vsub, enum vlr_ciph_result_cause
 
 /* Internal evaluation of requested ciphering mode.
  * Send set_ciph_mode() to MSC depending on the ciph_mode argument.
- * \param[in] vlr  VLR instance.
+ * \param[in] vlr VLR instance.
- * \param[in] fi  Calling FSM instance, for logging.
+ * \param[in] fi Calling FSM instance, for logging.
- * \param[in] msc_conn_ref  MSC conn to send to.
+ * \param[in] msc_conn_ref MSC conn to send to.
- * \param[in] ciph_mode  Ciphering config, to decide whether to do ciphering.
+ * \param[in] sec_ctx the security context to be established.
+ * \param[in] retrieve_imeisv request the IMEI in the ciphering mode command.
  * \returns 0 if no ciphering is needed or message was sent successfully,
  *          or a negative value if ciph_mode is invalid or sending failed.
  */
 int vlr_set_ciph_mode(struct vlr_instance *vlr,
 		      struct osmo_fsm_inst *fi,
 		      void *msc_conn_ref,
-		      bool umts_aka,
+		      enum vlr_subscr_security_context sec_ctx,
 		      bool retrieve_imeisv)
 {
+	bool umts_aka;
+
+	switch (sec_ctx) {
+	case VLR_SEC_CTX_GSM:
+		umts_aka = false;
+		break;
+	case VLR_SEC_CTX_UMTS:
+		umts_aka = true;
+		break;
+	case VLR_SEC_CTX_NONE:
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
 	LOGPFSML(fi, LOGL_DEBUG, "Set Ciphering Mode\n");
 	return vlr->ops.set_ciph_mode(msc_conn_ref, umts_aka, retrieve_imeisv);
 }

src/libvlr/vlr_access_req_fsm.c

@@ -297,7 +297,6 @@ static void _proc_arq_vlr_node2(struct osmo_fsm_inst *fi)
 {
 	struct proc_arq_priv *par = fi->priv;
 	struct vlr_subscr *vsub = par->vsub;
-	bool umts_aka;
 
 	LOGPFSM(fi, "%s()\n", __func__);
 
@@ -311,10 +310,7 @@ static void _proc_arq_vlr_node2(struct osmo_fsm_inst *fi)
 
 	switch (vsub->sec_ctx) {
 	case VLR_SEC_CTX_GSM:
-		umts_aka = false;
-		break;
 	case VLR_SEC_CTX_UMTS:
-		umts_aka = true;
 		break;
 	default:
 		LOGPFSML(fi, LOGL_ERROR, "Cannot start ciphering, security context is not established\n");
@@ -323,7 +319,7 @@ static void _proc_arq_vlr_node2(struct osmo_fsm_inst *fi)
 	}
 
 	if (vlr_set_ciph_mode(vsub->vlr, fi, par->msc_conn_ref,
-			      umts_aka,
+			      vsub->sec_ctx,
 			      vsub->vlr->cfg.retrieve_imeisv_ciphered)) {
 		LOGPFSML(fi, LOGL_ERROR,
 			 "Failed to send Ciphering Mode Command\n");

src/libvlr/vlr_lu_fsm.c

@@ -892,7 +892,6 @@ static void vlr_loc_upd_post_auth(struct osmo_fsm_inst *fi)
 {
 	struct lu_fsm_priv *lfp = lu_fsm_fi_priv(fi);
 	struct vlr_subscr *vsub = lfp->vsub;
-	bool umts_aka;
 
 	LOGPFSM(fi, "%s()\n", __func__);
 
@@ -914,10 +913,7 @@ static void vlr_loc_upd_post_auth(struct osmo_fsm_inst *fi)
 
 	switch (vsub->sec_ctx) {
 	case VLR_SEC_CTX_GSM:
-		umts_aka = false;
-		break;
 	case VLR_SEC_CTX_UMTS:
-		umts_aka = true;
 		break;
 	default:
 		LOGPFSML(fi, LOGL_ERROR, "Cannot start ciphering, security context is not established\n");
@@ -926,7 +922,7 @@ static void vlr_loc_upd_post_auth(struct osmo_fsm_inst *fi)
 	}
 
 	if (vlr_set_ciph_mode(vsub->vlr, fi, lfp->msc_conn_ref,
-			      umts_aka,
+			      vsub->sec_ctx,
 			      vsub->vlr->cfg.retrieve_imeisv_ciphered)) {
 		LOGPFSML(fi, LOGL_ERROR,
 			 "Failed to send Ciphering Mode Command\n");