msc_a,vlr: rename ciphering_required to is_ciphering_to_be_attempted

Clarify the name to avoid confusion in upcoming patches.

This function actually returns whether any ciphering mode besides A5/0
is enabled, and does not imply that ciphering is mandatory. A5/0 may
well be allowed when this function returns true.

Related: OS#4830
Change-Id: Ia55085e3b36feb275bcf92fc91a4be7d1c24a6b9
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index 9d3b5a2..53cafa4 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -417,7 +417,7 @@
 				net->vlr, msc_a, vlr_lu_type, tmsi, imsi,
 				&old_lai, &msc_a->via_cell.lai,
 				is_utran || net->authentication_required,
-				msc_a_require_ciphering(msc_a),
+				msc_a_is_ciphering_to_be_attempted(msc_a),
 				lu->key_seq,
 				osmo_gsm48_classmark1_is_r99(&lu->classmark1),
 				is_utran,
@@ -818,7 +818,7 @@
 			 req->cm_service_type,
 			 &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 req->cipher_key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, cm2_len),
 			 is_utran);
@@ -944,7 +944,7 @@
 			 VLR_PR_ARQ_T_CM_RE_ESTABLISH_REQ, 0,
 			 &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 req->cipher_key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, cm2_len),
 			 is_utran);
@@ -1306,7 +1306,7 @@
 			 net->vlr, msc_a,
 			 VLR_PR_ARQ_T_PAGING_RESP, 0, &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 pr->key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, classmark2_len),
 			 is_utran);
diff --git a/src/libmsc/msc_a.c b/src/libmsc/msc_a.c
index f00fb11..5d44686 100644
--- a/src/libmsc/msc_a.c
+++ b/src/libmsc/msc_a.c
@@ -106,7 +106,7 @@
 	return fi->priv;
 }
 
-bool msc_a_require_ciphering(const struct msc_a *msc_a)
+bool msc_a_is_ciphering_to_be_attempted(const struct msc_a *msc_a)
 {
 	struct gsm_network *net = msc_a_net(msc_a);
 	bool is_utran = (msc_a->c.ran->type == OSMO_RAT_UTRAN_IU);
diff --git a/src/libvlr/vlr_access_req_fsm.c b/src/libvlr/vlr_access_req_fsm.c
index 8daaaad..ce7c2af 100644
--- a/src/libvlr/vlr_access_req_fsm.c
+++ b/src/libvlr/vlr_access_req_fsm.c
@@ -67,7 +67,7 @@
 	uint32_t tmsi;
 	struct osmo_location_area_id lai;
 	bool authentication_required;
-	bool ciphering_required;
+	bool is_ciphering_to_be_attempted;
 	uint8_t key_seq;
 	bool is_r99;
 	bool is_utran;
@@ -272,7 +272,7 @@
 {
 	/* UTRAN: always send SecModeCmd, even if ciphering is not required.
 	 * GERAN: avoid sending CiphModeCmd if ciphering is not required. */
-	return par->is_utran || par->ciphering_required;
+	return par->is_utran || par->is_ciphering_to_be_attempted;
 }
 
 static void _proc_arq_vlr_node2(struct osmo_fsm_inst *fi)
@@ -320,7 +320,7 @@
 	 * are defined in 3GPP TS 33.102 */
 	/* For now we use a default value passed in to vlr_lu_fsm(). */
 	return par->authentication_required ||
-		(par->ciphering_required && !auth_try_reuse_tuple(par->vsub, par->key_seq));
+		(par->is_ciphering_to_be_attempted && !auth_try_reuse_tuple(par->vsub, par->key_seq));
 }
 
 /* after the IMSI is known */
@@ -634,7 +634,7 @@
 		 const struct osmo_mobile_identity *mi,
 		 const struct osmo_location_area_id *lai,
 		 bool authentication_required,
-		 bool ciphering_required,
+		 bool is_ciphering_to_be_attempted,
 		 uint8_t key_seq,
 		 bool is_r99, bool is_utran)
 {
@@ -657,7 +657,7 @@
 	par->parent_event_failure = parent_event_failure;
 	par->parent_event_data = parent_event_data;
 	par->authentication_required = authentication_required;
-	par->ciphering_required = ciphering_required;
+	par->is_ciphering_to_be_attempted = is_ciphering_to_be_attempted;
 	par->key_seq = key_seq;
 	par->is_r99 = is_r99;
 	par->is_utran = is_utran;
@@ -665,10 +665,10 @@
 	LOGPFSM(fi, "rev=%s net=%s%s%s\n",
 		is_r99 ? "R99" : "GSM",
 		is_utran ? "UTRAN" : "GERAN",
-		(authentication_required || ciphering_required)?
+		(authentication_required || is_ciphering_to_be_attempted) ?
 		" Auth" : " (no Auth)",
-		(authentication_required || ciphering_required)?
-			(ciphering_required? "+Ciph" : " (no Ciph)")
+		(authentication_required || is_ciphering_to_be_attempted) ?
+			(is_ciphering_to_be_attempted ? "+Ciph" : " (no Ciph)")
 			: "");
 
 	if (is_utran && !authentication_required)
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index 4f603b3..e8ceefd 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -676,7 +676,7 @@
 	struct osmo_location_area_id old_lai;
 	struct osmo_location_area_id new_lai;
 	bool authentication_required;
-	bool ciphering_required;
+	bool is_ciphering_to_be_attempted;
 	uint8_t key_seq;
 	bool is_r99;
 	bool is_utran;
@@ -699,7 +699,7 @@
 	 * are defined in 3GPP TS 33.102 */
 	/* For now we use a default value passed in to vlr_lu_fsm(). */
 	return lfp->authentication_required ||
-		(lfp->ciphering_required && !auth_try_reuse_tuple(lfp->vsub, lfp->key_seq));
+		(lfp->is_ciphering_to_be_attempted && !auth_try_reuse_tuple(lfp->vsub, lfp->key_seq));
 }
 
 /* Determine if sending of CMC/SMC is required */
@@ -707,7 +707,7 @@
 {
 	/* UTRAN: always send SecModeCmd, even if ciphering is not required.
 	 * GERAN: avoid sending CiphModeCmd if ciphering is not required. */
-	return lfp->is_utran || lfp->ciphering_required;
+	return lfp->is_utran || lfp->is_ciphering_to_be_attempted;
 }
 
 /* Determine if a HLR Update is required */
@@ -1475,7 +1475,7 @@
 	       const struct osmo_location_area_id *old_lai,
 	       const struct osmo_location_area_id *new_lai,
 	       bool authentication_required,
-	       bool ciphering_required,
+	       bool is_ciphering_to_be_attempted,
 	       uint8_t key_seq,
 	       bool is_r99, bool is_utran,
 	       bool assign_tmsi)
@@ -1499,7 +1499,7 @@
 	lfp->parent_event_failure = parent_event_failure;
 	lfp->parent_event_data = parent_event_data;
 	lfp->authentication_required = authentication_required;
-	lfp->ciphering_required = ciphering_required;
+	lfp->is_ciphering_to_be_attempted = is_ciphering_to_be_attempted;
 	lfp->key_seq = key_seq;
 	lfp->is_r99 = is_r99;
 	lfp->is_utran = is_utran;
@@ -1514,10 +1514,10 @@
 	LOGPFSM(fi, "rev=%s net=%s%s%s\n",
 		is_r99 ? "R99" : "GSM",
 		is_utran ? "UTRAN" : "GERAN",
-		(authentication_required || ciphering_required)?
+		(authentication_required || is_ciphering_to_be_attempted) ?
 		" Auth" : " (no Auth)",
-		(authentication_required || ciphering_required)?
-			(ciphering_required? "+Ciph" : " (no Ciph)")
+		(authentication_required || is_ciphering_to_be_attempted) ?
+			(is_ciphering_to_be_attempted ? "+Ciph" : " (no Ciph)")
 			: "");
 
 	if (is_utran && !authentication_required)