Refactor

Former-commit-id: 7ae705b1f1

dns/override/dns_override_darwin.go

@@ -0,0 +1,68 @@
+//go:build darwin && !ios
+
+package olm
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/fosrl/newt/logger"
+	"github.com/fosrl/olm/dns"
+	platform "github.com/fosrl/olm/dns/platform"
+)
+
+var configurator platform.DNSConfigurator
+
+// SetupDNSOverride configures the system DNS to use the DNS proxy on macOS
+// Uses scutil for DNS configuration
+func SetupDNSOverride(interfaceName string, dnsProxy *dns.DNSProxy) error {
+	if dnsProxy == nil {
+		return fmt.Errorf("DNS proxy is nil")
+	}
+
+	var err error
+	configurator, err = platform.NewDarwinDNSConfigurator()
+	if err != nil {
+		return fmt.Errorf("failed to create Darwin DNS configurator: %w", err)
+	}
+
+	logger.Info("Using Darwin scutil DNS configurator")
+
+	// Get current DNS servers before changing
+	currentDNS, err := configurator.GetCurrentDNS()
+	if err != nil {
+		logger.Warn("Could not get current DNS: %v", err)
+	} else {
+		logger.Info("Current DNS servers: %v", currentDNS)
+	}
+
+	// Set new DNS servers to point to our proxy
+	newDNS := []netip.Addr{
+		dnsProxy.GetProxyIP(),
+	}
+
+	logger.Info("Setting DNS servers to: %v", newDNS)
+	originalDNS, err := configurator.SetDNS(newDNS)
+	if err != nil {
+		return fmt.Errorf("failed to set DNS: %w", err)
+	}
+
+	logger.Info("Original DNS servers backed up: %v", originalDNS)
+	return nil
+}
+
+// RestoreDNSOverride restores the original DNS configuration
+func RestoreDNSOverride() error {
+	if configurator == nil {
+		logger.Debug("No DNS configurator to restore")
+		return nil
+	}
+
+	logger.Info("Restoring original DNS configuration")
+	if err := configurator.RestoreDNS(); err != nil {
+		return fmt.Errorf("failed to restore DNS: %w", err)
+	}
+
+	logger.Info("DNS configuration restored successfully")
+	return nil
+}

dns/override/dns_override_unix.go

@@ -0,0 +1,104 @@
+//go:build (linux && !android) || freebsd
+
+package olm
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/fosrl/newt/logger"
+	"github.com/fosrl/olm/dns"
+	platform "github.com/fosrl/olm/dns/platform"
+)
+
+var configurator platform.DNSConfigurator
+
+// SetupDNSOverride configures the system DNS to use the DNS proxy on Linux/FreeBSD
+// Tries systemd-resolved, NetworkManager, resolvconf, or falls back to /etc/resolv.conf
+func SetupDNSOverride(interfaceName string, dnsProxy *dns.DNSProxy) error {
+	if dnsProxy == nil {
+		return fmt.Errorf("DNS proxy is nil")
+	}
+
+	var err error
+
+	// Try systemd-resolved first (most modern)
+	if platform.IsSystemdResolvedAvailable() && interfaceName != "" {
+		configurator, err = platform.NewSystemdResolvedDNSConfigurator(interfaceName)
+		if err == nil {
+			logger.Info("Using systemd-resolved DNS configurator")
+			return setDNS(dnsProxy, configurator)
+		}
+		logger.Debug("systemd-resolved not available: %v", err)
+	}
+
+	// Try NetworkManager (common on desktops)
+	if platform.IsNetworkManagerAvailable() && interfaceName != "" {
+		configurator, err = platform.NewNetworkManagerDNSConfigurator(interfaceName)
+		if err == nil {
+			logger.Info("Using NetworkManager DNS configurator")
+			return setDNS(dnsProxy, configurator)
+		}
+		logger.Debug("NetworkManager not available: %v", err)
+	}
+
+	// Try resolvconf (common on older systems)
+	if platform.IsResolvconfAvailable() && interfaceName != "" {
+		configurator, err = platform.NewResolvconfDNSConfigurator(interfaceName)
+		if err == nil {
+			logger.Info("Using resolvconf DNS configurator")
+			return setDNS(dnsProxy, configurator)
+		}
+		logger.Debug("resolvconf not available: %v", err)
+	}
+
+	// Fall back to direct file manipulation
+	configurator, err = platform.NewFileDNSConfigurator()
+	if err != nil {
+		return fmt.Errorf("failed to create file DNS configurator: %w", err)
+	}
+
+	logger.Info("Using file-based DNS configurator")
+	return setDNS(dnsProxy, configurator)
+}
+
+// setDNS is a helper function to set DNS and log the results
+func setDNS(dnsProxy *dns.DNSProxy, conf platform.DNSConfigurator) error {
+	// Get current DNS servers before changing
+	currentDNS, err := conf.GetCurrentDNS()
+	if err != nil {
+		logger.Warn("Could not get current DNS: %v", err)
+	} else {
+		logger.Info("Current DNS servers: %v", currentDNS)
+	}
+
+	// Set new DNS servers to point to our proxy
+	newDNS := []netip.Addr{
+		dnsProxy.GetProxyIP(),
+	}
+
+	logger.Info("Setting DNS servers to: %v", newDNS)
+	originalDNS, err := conf.SetDNS(newDNS)
+	if err != nil {
+		return fmt.Errorf("failed to set DNS: %w", err)
+	}
+
+	logger.Info("Original DNS servers backed up: %v", originalDNS)
+	return nil
+}
+
+// RestoreDNSOverride restores the original DNS configuration
+func RestoreDNSOverride() error {
+	if configurator == nil {
+		logger.Debug("No DNS configurator to restore")
+		return nil
+	}
+
+	logger.Info("Restoring original DNS configuration")
+	if err := configurator.RestoreDNS(); err != nil {
+		return fmt.Errorf("failed to restore DNS: %w", err)
+	}
+
+	logger.Info("DNS configuration restored successfully")
+	return nil
+}

dns/override/dns_override_windows.go

@@ -0,0 +1,68 @@
+//go:build windows
+
+package olm
+
+import (
+	"fmt"
+	"net/netip"
+
+	"github.com/fosrl/newt/logger"
+	"github.com/fosrl/olm/dns"
+	platform "github.com/fosrl/olm/dns/platform"
+)
+
+var configurator platform.DNSConfigurator
+
+// SetupDNSOverride configures the system DNS to use the DNS proxy on Windows
+// Uses registry-based configuration (automatically extracts interface GUID)
+func SetupDNSOverride(interfaceName string, dnsProxy *dns.DNSProxy) error {
+	if dnsProxy == nil {
+		return fmt.Errorf("DNS proxy is nil")
+	}
+
+	var err error
+	configurator, err = platform.NewWindowsDNSConfigurator(interfaceName)
+	if err != nil {
+		return fmt.Errorf("failed to create Windows DNS configurator: %w", err)
+	}
+
+	logger.Info("Using Windows registry DNS configurator for interface: %s", interfaceName)
+
+	// Get current DNS servers before changing
+	currentDNS, err := configurator.GetCurrentDNS()
+	if err != nil {
+		logger.Warn("Could not get current DNS: %v", err)
+	} else {
+		logger.Info("Current DNS servers: %v", currentDNS)
+	}
+
+	// Set new DNS servers to point to our proxy
+	newDNS := []netip.Addr{
+		dnsProxy.GetProxyIP(),
+	}
+
+	logger.Info("Setting DNS servers to: %v", newDNS)
+	originalDNS, err := configurator.SetDNS(newDNS)
+	if err != nil {
+		return fmt.Errorf("failed to set DNS: %w", err)
+	}
+
+	logger.Info("Original DNS servers backed up: %v", originalDNS)
+	return nil
+}
+
+// RestoreDNSOverride restores the original DNS configuration
+func RestoreDNSOverride() error {
+	if configurator == nil {
+		logger.Debug("No DNS configurator to restore")
+		return nil
+	}
+
+	logger.Info("Restoring original DNS configuration")
+	if err := configurator.RestoreDNS(); err != nil {
+		return fmt.Errorf("failed to restore DNS: %w", err)
+	}
+
+	logger.Info("DNS configuration restored successfully")
+	return nil
+}

dns/platform/windows.go

@@ -6,13 +6,13 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/netip"
 	"syscall"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/registry"
-	"golang.zx2c4.com/wireguard/tun"
 )
 
 var (
@@ -33,13 +33,13 @@ type WindowsDNSConfigurator struct {
 }
 
 // NewWindowsDNSConfigurator creates a new Windows DNS configurator
-// Accepts a TUN device and extracts the GUID internally
-func NewWindowsDNSConfigurator(tunDevice tun.Device) (*WindowsDNSConfigurator, error) {
-	if tunDevice == nil {
-		return nil, fmt.Errorf("TUN device is required")
+// Accepts an interface name and extracts the GUID internally
+func NewWindowsDNSConfigurator(interfaceName string) (*WindowsDNSConfigurator, error) {
+	if interfaceName == "" {
+		return nil, fmt.Errorf("interface name is required")
 	}
 
-	guid, err := getInterfaceGUIDString(tunDevice)
+	guid, err := getInterfaceGUIDString(interfaceName)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get interface GUID: %w", err)
 	}
@@ -268,24 +268,21 @@ func closeKey(closer io.Closer) {
 
 // getInterfaceGUIDString retrieves the GUID string for a Windows TUN interface
 // This is required for registry-based DNS configuration on Windows
-func getInterfaceGUIDString(tunDevice tun.Device) (string, error) {
-	if tunDevice == nil {
-		return "", fmt.Errorf("TUN device is nil")
+func getInterfaceGUIDString(interfaceName string) (string, error) {
+	if interfaceName == "" {
+		return "", fmt.Errorf("interface name is required")
 	}
 
-	// The wireguard-go Windows TUN device has a LUID() method
-	// We need to use type assertion to access it
-	type nativeTun interface {
-		LUID() uint64
+	iface, err := net.InterfaceByName(interfaceName)
+	if err != nil {
+		return "", fmt.Errorf("failed to get interface %s: %w", interfaceName, err)
 	}
 
-	nativeDev, ok := tunDevice.(nativeTun)
-	if !ok {
-		return "", fmt.Errorf("TUN device does not support LUID retrieval (not a native Windows TUN device)")
+	luid, err := indexToLUID(uint32(iface.Index))
+	if err != nil {
+		return "", fmt.Errorf("failed to convert index to LUID: %w", err)
 	}
 
-	luid := nativeDev.LUID()
-
 	// Convert LUID to GUID using Windows API
 	guid, err := luidToGUID(luid)
 	if err != nil {
@@ -295,6 +292,27 @@ func getInterfaceGUIDString(tunDevice tun.Device) (string, error) {
 	return guid, nil
 }
 
+// indexToLUID converts a Windows interface index to a LUID
+func indexToLUID(index uint32) (uint64, error) {
+	var luid uint64
+
+	// Load the iphlpapi.dll and get the ConvertInterfaceIndexToLuid function
+	iphlpapi := windows.NewLazySystemDLL("iphlpapi.dll")
+	convertInterfaceIndexToLuid := iphlpapi.NewProc("ConvertInterfaceIndexToLuid")
+
+	// Call the Windows API
+	ret, _, err := convertInterfaceIndexToLuid.Call(
+		uintptr(index),
+		uintptr(unsafe.Pointer(&luid)),
+	)
+
+	if ret != 0 {
+		return 0, fmt.Errorf("ConvertInterfaceIndexToLuid failed with code %d: %w", ret, err)
+	}
+
+	return luid, nil
+}
+
 // luidToGUID converts a Windows LUID (Locally Unique Identifier) to a GUID string
 // using the Windows ConvertInterface* APIs
 func luidToGUID(luid uint64) (string, error) {