uqmi: use built-in command for data-link verification

uqmi contains a command for directly querying the modem if there
is a valid data connection, so let's use it.

This avoids the cases were all previous tests are succesful, but the
actual data link is not up for some reasons, leading to states were we
thought the link was up when it actually wasn't ..

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>

package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh

@@ -27,7 +27,7 @@ proto_qmi_init_config() {
 
 proto_qmi_setup() {
 	local interface="$1"
-	local dataformat
+	local dataformat connstat
 	local device apn auth username password pincode delay modes pdptype profile dhcpv6 autoconnect plmn $PROTO_DEFAULT_OPTIONS
 	local cid_4 pdh_4 cid_6 pdh_6
 	local ip_6 ip_prefix_length gateway_6 dns1_6 dns2_6
@@ -164,6 +164,15 @@ proto_qmi_setup() {
 			proto_notify_error "$interface" CALL_FAILED
 			return 1
 		fi
+
+        # Check data connection state
+		connstat=$(uqmi -s -d "$device" --get-data-status)
+                [ "$connstat" == '"connected"' ] || {
+                        echo "No data link!"
+                        uqmi -s -d "$device" --set-client-id wds,"$cid_4" --release-client-id wds
+                        proto_notify_error "$interface" CALL_FAILED
+                        return 1
+                }
 	}
 
 	[ "$pdptype" = "ipv6" -o "$pdptype" = "ipv4v6" ] && {
@@ -192,6 +201,15 @@ proto_qmi_setup() {
 			proto_notify_error "$interface" CALL_FAILED
 			return 1
 		fi
+
+        # Check data connection state
+		connstat=$(uqmi -s -d "$device" --get-data-status)
+                [ "$connstat" == '"connected"' ] || {
+                        echo "No data link!"
+                        uqmi -s -d "$device" --set-client-id wds,"$cid_6" --release-client-id wds
+                        proto_notify_error "$interface" CALL_FAILED
+                        return 1
+                }
 	}
 
 	echo "Setting up $ifname"