chore(config): use openvpn protocol string field instead of TCP bool

internal/storage/filter.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
@@ -147,7 +148,7 @@ func filterByProtocol(selection settings.ServerSelection,
 	case vpn.Wireguard:
 		return !serverUDP
 	default: // OpenVPN
-		wantTCP := *selection.OpenVPN.TCP
+		wantTCP := selection.OpenVPN.Protocol == constants.TCP
 		wantUDP := !wantTCP
 		return (wantTCP && !serverTCP) || (wantUDP && !serverUDP)
 	}

internal/storage/formatting.go

@@ -22,7 +22,7 @@ func noServerFoundError(selection settings.ServerSelection) (err error) {
 	messageParts = append(messageParts, "VPN "+selection.VPN)
 
 	protocol := constants.UDP
-	if *selection.OpenVPN.TCP {
+	if selection.OpenVPN.Protocol == constants.TCP {
 		protocol = constants.TCP
 	}
 	messageParts = append(messageParts, "protocol "+protocol)