Feat: ExpressVPN support (#623)

internal/provider/expressvpn/openvpnconf.go

@@ -0,0 +1,85 @@
+package expressvpn
+
+import (
+	"strconv"
+
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/utils"
+)
+
+func (p *Provider) BuildConf(connection models.Connection,
+	settings configuration.OpenVPN) (lines []string, err error) {
+	if settings.Cipher == "" {
+		settings.Cipher = constants.AES256cbc
+	}
+	if settings.Auth == "" {
+		settings.Auth = constants.SHA512
+	}
+
+	if settings.MSSFix == 0 {
+		settings.MSSFix = 1200
+	}
+
+	lines = []string{
+		"client",
+		"nobind",
+		"tls-exit",
+		"dev " + settings.Interface,
+		"verb " + strconv.Itoa(settings.Verbosity),
+
+		// Expressvpn specific
+		"fast-io",
+		"fragment 1300",
+		"mssfix " + strconv.Itoa(int(settings.MSSFix)),
+		"sndbuf 524288",
+		"rcvbuf 524288",
+		"verify-x509-name Server name-prefix", // security hole I guess?
+		"remote-cert-tls server",              // updated name of ns-cert-type
+		"key-direction 1",
+		"auth-user-pass " + constants.OpenVPNAuthConf,
+		"auth " + settings.Auth,
+
+		// Added constant values
+		"mute-replay-warnings",
+		"auth-nocache",
+		"pull-filter ignore \"auth-token\"", // prevent auth failed loops
+		"auth-retry nointeract",
+		"suppress-timestamps",
+
+		// Modified variables
+		connection.OpenVPNProtoLine(),
+		connection.OpenVPNRemoteLine(),
+	}
+
+	lines = append(lines, utils.CipherLines(settings.Cipher, settings.Version)...)
+
+	if connection.Protocol == constants.UDP {
+		lines = append(lines, "explicit-exit-notify")
+	}
+
+	if !settings.Root {
+		lines = append(lines, "user "+settings.ProcUser)
+		lines = append(lines, "persist-tun")
+		lines = append(lines, "persist-key")
+	}
+
+	if !settings.IPv6 {
+		lines = append(lines, `pull-filter ignore "route-ipv6"`)
+		lines = append(lines, `pull-filter ignore "ifconfig-ipv6"`)
+	}
+
+	lines = append(lines, utils.WrapOpenvpnCert(
+		constants.ExpressvpnCert)...)
+	lines = append(lines, utils.WrapOpenvpnRSAKey(
+		constants.ExpressvpnRSAKey)...)
+	lines = append(lines, utils.WrapOpenvpnTLSAuth(
+		constants.ExpressvpnTLSAuthOpenvpnStaticKeyV1)...)
+	lines = append(lines, utils.WrapOpenvpnCA(
+		constants.ExpressvpnCA)...)
+
+	lines = append(lines, "")
+
+	return lines, nil
+}