# 引入地址
https://github.com/tailscale/tailscale/blob/main/wgengine/magicsock/debugknobs.go
# 原理：有环境变量可以强制使用derp
TS_DEBUG_ALWAYS_USE_DERP=true

# Windows下，使用PowerShell在管理员模式下执行
# 启用环境变量
$reg = "HKLM:\SYSTEM\CurrentControlSet\Services\Tailscale"
$val = "TS_DEBUG_ALWAYS_USE_DERP=true"
if (Get-ItemProperty -Path $reg -Name Environment -ErrorAction SilentlyContinue) {
  $cur = Get-ItemPropertyValue -Path $reg -Name Environment
  if ($cur -notcontains $val) {
    Set-ItemProperty -Path $reg -Name Environment -Value ($cur + $val)
  }
} else {
  New-ItemProperty -Path $reg -Name Environment -Value $val -PropertyType MultiString
}
Restart-Service Tailscale -Force

# 禁用环境变量
$reg = "HKLM:\SYSTEM\CurrentControlSet\Services\Tailscale"
$val = "TS_DEBUG_ALWAYS_USE_DERP=true"
if (Get-ItemProperty -Path $reg -Name Environment -ErrorAction SilentlyContinue) {
  $cur = Get-ItemPropertyValue -Path $reg -Name Environment
  $new = $cur | Where-Object { $_ -ne $val }
  if ($new.Count -eq 0) {
    Remove-ItemProperty -Path $reg -Name Environment
  } else {
    Set-ItemProperty -Path $reg -Name Environment -Value $new
  }
}
Restart-Service Tailscale -Force