fix(portforward): rework run loop and fix deadlocks (#1874)

internal/portforward/service/settings.go

@@ -0,0 +1,79 @@
+package service
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants/providers"
+	"github.com/qdm12/gluetun/internal/provider"
+	"github.com/qdm12/gosettings"
+)
+
+type Settings struct {
+	UserSettings  settings.PortForwarding
+	PortForwarder provider.PortForwarder
+	Gateway       netip.Addr // needed for PIA and ProtonVPN
+	ServerName    string     // needed for PIA
+	Interface     string     // needed for PIA and ProtonVPN, tun0 for example
+	VPNProvider   string     // used to validate new settings
+}
+
+// UpdateWith deep copies the receiving settings, overrides the copy with
+// fields set in the partialUpdate argument, validates the new settings
+// and returns them if they are valid, or returns an error otherwise.
+// In all cases, the receiving settings are unmodified.
+func (s Settings) UpdateWith(partialUpdate Settings) (updatedSettings Settings, err error) {
+	updatedSettings = s.copy()
+	updatedSettings.overrideWith(partialUpdate)
+	err = updatedSettings.validate()
+	if err != nil {
+		return updatedSettings, fmt.Errorf("validating new settings: %w", err)
+	}
+	return updatedSettings, nil
+}
+
+func (s Settings) copy() (copied Settings) {
+	copied.UserSettings = s.UserSettings.Copy()
+	copied.PortForwarder = s.PortForwarder
+	copied.Gateway = s.Gateway
+	copied.ServerName = s.ServerName
+	copied.Interface = s.Interface
+	copied.VPNProvider = s.VPNProvider
+	return copied
+}
+
+func (s *Settings) overrideWith(update Settings) {
+	s.UserSettings.OverrideWith(update.UserSettings)
+	s.PortForwarder = gosettings.OverrideWithInterface(s.PortForwarder, update.PortForwarder)
+	s.Gateway = gosettings.OverrideWithValidator(s.Gateway, update.Gateway)
+	s.ServerName = gosettings.OverrideWithString(s.ServerName, update.ServerName)
+	s.Interface = gosettings.OverrideWithString(s.Interface, update.Interface)
+	s.VPNProvider = gosettings.OverrideWithString(s.VPNProvider, update.VPNProvider)
+}
+
+var (
+	ErrVPNProviderNotSet   = errors.New("VPN provider not set")
+	ErrServerNameNotSet    = errors.New("server name not set")
+	ErrPortForwarderNotSet = errors.New("port forwarder not set")
+	ErrGatewayNotSet       = errors.New("gateway not set")
+	ErrInterfaceNotSet     = errors.New("interface not set")
+)
+
+func (s *Settings) validate() (err error) {
+	switch {
+	case s.VPNProvider == "":
+		return fmt.Errorf("%w", ErrVPNProviderNotSet)
+	case s.VPNProvider == providers.PrivateInternetAccess && s.ServerName == "":
+		return fmt.Errorf("%w", ErrServerNameNotSet)
+	case s.PortForwarder == nil:
+		return fmt.Errorf("%w", ErrPortForwarderNotSet)
+	case !s.Gateway.IsValid():
+		return fmt.Errorf("%w", ErrGatewayNotSet)
+	case s.Interface == "":
+		return fmt.Errorf("%w", ErrInterfaceNotSet)
+	}
+
+	return s.UserSettings.Validate(s.VPNProvider)
+}