LCLS: fix LCLS-CONNECT-CONTROL encoder

Previously it could encode both incorrect values as well as incorrect
message. Let's fix this by explicitly checking for invalid values and
ensuring that at least one of the parameters is valid.

This function have no external or internal users so it's better to fix
type signature as well to match the rest of gsm0808_create_lcls_*().

Change-Id: I7b33a771acbd391c5f9a494d6450edb18511433f

TODO-RELEASE

@@ -19,3 +19,4 @@ libosmogsm     gsm0808_create_cipher_reject()          use enum as parameter
 libosmogsm	osmo_gsup_message			extended with SMS related fields
 libosmogsm	osmo_gsup_sms_{en|de}code_sm_rp_da	GSUP SM-RP-DA coding helpers
 libosmogsm	osmo_gsup_sms_{en|de}code_sm_rp_oa	GSUP SM-RP-OA coding helpers
+libosmogsm	gsm0808_create_lcls_conn_ctrl()		API/ABI break: change parameters from pointers to plain values

include/osmocom/gsm/gsm0808.h

@@ -92,8 +92,8 @@ struct msgb *gsm0808_create_paging(const char *imsi, const uint32_t *tmsi,
 				   const struct gsm0808_cell_id_list *cil,
 				   const uint8_t *chan_needed)
 				   OSMO_DEPRECATED("use gsm0808_create_paging2 instead");
-struct msgb *gsm0808_create_lcls_conn_ctrl(enum gsm0808_lcls_config *config,
-					   enum gsm0808_lcls_control *control);
+struct msgb *gsm0808_create_lcls_conn_ctrl(enum gsm0808_lcls_config config,
+					   enum gsm0808_lcls_control control);
 struct msgb *gsm0808_create_lcls_conn_ctrl_ack(enum gsm0808_lcls_status status);
 struct msgb *gsm0808_create_lcls_notification(enum gsm0808_lcls_status status, bool break_req);
 

src/gsm/gsm0808.c

@@ -312,19 +312,24 @@ struct msgb *gsm0808_create_cipher_reject_ext(enum gsm0808_cause_class class, ui
  *  \param[in] config LCLS Configuration
  *  \param[in] control LCLS Connection Status Control
  *  \returns callee-allocated msgb with BSSMAP LCLS NOTIFICATION */
-struct msgb *gsm0808_create_lcls_conn_ctrl(enum gsm0808_lcls_config *config,
-					   enum gsm0808_lcls_control *control)
+struct msgb *gsm0808_create_lcls_conn_ctrl(enum gsm0808_lcls_config config,
+					   enum gsm0808_lcls_control control)
 {
-	struct msgb *msg = msgb_alloc_headroom(BSSMAP_MSG_SIZE, BSSMAP_MSG_HEADROOM,
-					       "bssmap: LCLS CONN CTRL");
+	struct msgb *msg;
+
+	/* According to NOTE 1 in §3.2.1.91 at least one of the parameters is required */
+	if (config == GSM0808_LCLS_CFG_NA && control == GSM0808_LCLS_CSC_NA)
+		return NULL;
+
+	msg = msgb_alloc_headroom(BSSMAP_MSG_SIZE, BSSMAP_MSG_HEADROOM, "bssmap: LCLS CONN CTRL");
 	if (!msg)
 		return NULL;
 
 	msgb_v_put(msg, BSS_MAP_MSG_LCLS_CONNECT_CTRL);
-	if (config)
-		msgb_tv_put(msg, GSM0808_IE_LCLS_CONFIG, *config);
-	if (control)
-		msgb_tv_put(msg, GSM0808_IE_LCLS_CONFIG, *control);
+	if (config != GSM0808_LCLS_CFG_NA)
+		msgb_tv_put(msg, GSM0808_IE_LCLS_CONFIG, config);
+	if (control != GSM0808_LCLS_CSC_NA)
+		msgb_tv_put(msg, GSM0808_IE_LCLS_CONFIG, control);
 	msg->l3h = msgb_tv_push(msg, BSSAP_MSG_BSS_MANAGEMENT, msgb_length(msg));
 
 	return msg;