Refactor

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
+}