Files
ctrld/vpn_dns_windows.go
2026-03-10 17:18:23 +07:00

101 lines
2.8 KiB
Go

//go:build windows
package ctrld
import (
"context"
"strings"
"syscall"
"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
)
// DiscoverVPNDNS discovers DNS servers and search domains from non-physical (VPN) interfaces.
// Only called when dnsIntercept is active.
func DiscoverVPNDNS(ctx context.Context) []VPNDNSConfig {
logger := LoggerFromCtx(ctx)
Log(ctx, logger.Debug(), "Discovering VPN DNS configurations on Windows")
flags := winipcfg.GAAFlagIncludeGateways | winipcfg.GAAFlagIncludePrefix
aas, err := winipcfg.GetAdaptersAddresses(syscall.AF_UNSPEC, flags)
if err != nil {
Log(ctx, logger.Error().Err(err), "Failed to get adapters addresses")
return nil
}
Log(ctx, logger.Debug(), "Found %d network adapters", len(aas))
// Get valid (physical/hardware) interfaces to filter them out
validInterfacesMap := ValidInterfaces(ctx)
var vpnConfigs []VPNDNSConfig
for _, aa := range aas {
// Skip adapters that are not up
if aa.OperStatus != winipcfg.IfOperStatusUp {
Log(ctx, logger.Debug(), "Skipping adapter %s - not up, status: %d",
aa.FriendlyName(), aa.OperStatus)
continue
}
// Skip software loopback
if aa.IfType == winipcfg.IfTypeSoftwareLoopback {
Log(ctx, logger.Debug(), "Skipping %s (software loopback)", aa.FriendlyName())
continue
}
// INVERT the ValidInterfaces filter: we want non-physical/non-hardware adapters
// that are UP and have DNS servers AND DNS suffixes
_, isValidPhysical := validInterfacesMap[aa.FriendlyName()]
if isValidPhysical {
Log(ctx, logger.Debug(), "Skipping %s (physical/hardware adapter)", aa.FriendlyName())
continue
}
// Collect DNS servers
var servers []string
for dns := aa.FirstDNSServerAddress; dns != nil; dns = dns.Next {
ip := dns.Address.IP()
if ip == nil {
continue
}
ipStr := ip.String()
if ip.IsLoopback() {
continue
}
servers = append(servers, ipStr)
}
// Collect DNS suffixes (search/match domains)
var domains []string
for suffix := aa.FirstDNSSuffix; suffix != nil; suffix = suffix.Next {
domain := strings.TrimSpace(suffix.String())
if domain != "" {
domains = append(domains, domain)
}
}
// Only include interfaces that have BOTH DNS servers AND search domains
if len(servers) > 0 && len(domains) > 0 {
config := VPNDNSConfig{
InterfaceName: aa.FriendlyName(),
Servers: servers,
Domains: domains,
}
vpnConfigs = append(vpnConfigs, config)
Log(ctx, logger.Debug(), "Found VPN DNS config - Interface: %s, Servers: %v, Domains: %v",
config.InterfaceName, config.Servers, config.Domains)
} else {
Log(ctx, logger.Debug(), "Skipping %s - insufficient DNS config (servers: %d, domains: %d)",
aa.FriendlyName(), len(servers), len(domains))
}
}
Log(ctx, logger.Debug(), "VPN DNS discovery completed: found %d VPN interfaces", len(vpnConfigs))
return vpnConfigs
}