Refactor (#174)

- Goal was to simplify main.go complexity
- Use common structures and interfaces for all vpn providers
- Moved files around
- Removed some alias models

internal/provider/mullvad.go

@@ -0,0 +1,115 @@
+package provider
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/qdm12/golibs/files"
+	"github.com/qdm12/golibs/logging"
+	"github.com/qdm12/private-internet-access-docker/internal/constants"
+	"github.com/qdm12/private-internet-access-docker/internal/models"
+)
+
+type mullvad struct {
+	fileManager files.FileManager
+	logger      logging.Logger
+}
+
+func newMullvad(fileManager files.FileManager, logger logging.Logger) *mullvad {
+	return &mullvad{
+		fileManager: fileManager,
+		logger:      logger.WithPrefix("Mullvad configurator: "),
+	}
+}
+
+func (m *mullvad) GetOpenVPNConnections(selection models.ServerSelection) (connections []models.OpenVPNConnection, err error) {
+	servers := constants.MullvadServerFilter(selection.Country, selection.City, selection.ISP)
+	if len(servers) == 0 {
+		return nil, fmt.Errorf("no server found for country %q, city %q and ISP %q", selection.Country, selection.City, selection.ISP)
+	}
+	for _, server := range servers {
+		port := server.DefaultPort
+		if selection.CustomPort > 0 {
+			port = selection.CustomPort
+		}
+		for _, IP := range server.IPs {
+			if selection.TargetIP != nil {
+				if selection.TargetIP.Equal(IP) {
+					return []models.OpenVPNConnection{{IP: IP, Port: port, Protocol: selection.Protocol}}, nil
+				}
+			} else {
+				connections = append(connections, models.OpenVPNConnection{IP: IP, Port: port, Protocol: selection.Protocol})
+			}
+		}
+	}
+	if selection.TargetIP != nil {
+		return nil, fmt.Errorf("target IP address %q not found in IP addresses", selection.TargetIP)
+	}
+	return connections, nil
+}
+
+func (m *mullvad) BuildConf(connections []models.OpenVPNConnection, verbosity, uid, gid int, root bool, cipher, auth string, extras models.ExtraConfigOptions) (err error) {
+	if len(connections) == 0 {
+		return fmt.Errorf("at least one connection string is expected")
+	}
+	if len(cipher) == 0 {
+		cipher = aes256cbc
+	}
+	lines := []string{
+		"client",
+		"dev tun",
+		"nobind",
+		"persist-key",
+		"remote-cert-tls server",
+
+		// Mullvad specific
+		"ping 10",
+		"ping-restart 60",
+		"sndbuf 524288",
+		"rcvbuf 524288",
+		"tls-cipher TLS-DHE-RSA-WITH-AES-256-GCM-SHA384:TLS-DHE-RSA-WITH-AES-256-CBC-SHA",
+		"tun-ipv6",
+		"fast-io",
+
+		// Added constant values
+		"mute-replay-warnings",
+		"auth-nocache",
+		"pull-filter ignore \"auth-token\"", // prevent auth failed loops
+		"auth-retry nointeract",
+		"remote-random",
+		"suppress-timestamps",
+
+		// Modified variables
+		fmt.Sprintf("verb %d", verbosity),
+		fmt.Sprintf("auth-user-pass %s", constants.OpenVPNAuthConf),
+		fmt.Sprintf("proto %s", string(connections[0].Protocol)),
+		fmt.Sprintf("cipher %s", cipher),
+	}
+	if !root {
+		lines = append(lines, "user nonrootuser")
+	}
+	for _, connection := range connections {
+		lines = append(lines, fmt.Sprintf("remote %s %d", connection.IP.String(), connection.Port))
+	}
+	lines = append(lines, []string{
+		"<ca>",
+		"-----BEGIN CERTIFICATE-----",
+		constants.MullvadCertificate,
+		"-----END CERTIFICATE-----",
+		"</ca>",
+		"",
+	}...)
+	return m.fileManager.WriteLinesToFile(string(constants.OpenVPNConf), lines, files.Ownership(uid, gid), files.Permissions(0400))
+}
+
+func (m *mullvad) GetPortForward() (port uint16, err error) {
+	panic("port forwarding is not supported for mullvad")
+}
+
+func (m *mullvad) WritePortForward(filepath models.Filepath, port uint16, uid, gid int) (err error) {
+	panic("port forwarding is not supported for mullvad")
+}
+
+func (m *mullvad) AllowPortForwardFirewall(ctx context.Context, device models.VPNDevice, port uint16) (err error) {
+	panic("port forwarding is not supported for mullvad")
+}