Maint: internal/vpn package for vpn loop

internal/vpn/portforward.go

@@ -0,0 +1,62 @@
+package vpn
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/portforward"
+	"github.com/qdm12/gluetun/internal/provider"
+)
+
+var (
+	errObtainVPNLocalGateway = errors.New("cannot obtain VPN local gateway IP")
+	errStartPortForwarding   = errors.New("cannot start port forwarding")
+)
+
+func (l *Loop) startPortForwarding(ctx context.Context, enabled bool,
+	portForwarder provider.PortForwarder, serverName string) (err error) {
+	if !enabled {
+		return nil
+	}
+
+	// only used for PIA for now
+	gateway, err := l.routing.VPNLocalGatewayIP()
+	if err != nil {
+		return fmt.Errorf("%w: %s", errObtainVPNLocalGateway, err)
+	}
+	l.logger.Info("VPN gateway IP address: " + gateway.String())
+
+	pfData := portforward.StartData{
+		PortForwarder: portForwarder,
+		Gateway:       gateway,
+		ServerName:    serverName,
+		Interface:     constants.TUN,
+	}
+	_, err = l.portForward.Start(ctx, pfData)
+	if err != nil {
+		return fmt.Errorf("%w: %s", errStartPortForwarding, err)
+	}
+
+	return nil
+}
+
+func (l *Loop) stopPortForwarding(ctx context.Context, enabled bool,
+	timeout time.Duration) {
+	if !enabled {
+		return // nothing to stop
+	}
+
+	if timeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+		defer cancel()
+	}
+
+	_, err := l.portForward.Stop(ctx)
+	if err != nil {
+		l.logger.Error("cannot stop port forwarding: " + err.Error())
+	}
+}