91 lines
2.1 KiB
Go
91 lines
2.1 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
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*/
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package conf
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import (
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"fmt"
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"log"
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"net"
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"syscall"
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"time"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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//sys internetGetConnectedState(flags *uint32, reserved uint32) (connected bool) = wininet.InternetGetConnectedState
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func resolveHostname(name string) (resolvedIPString string, err error) {
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maxTries := 10
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systemJustBooted := windows.DurationSinceBoot() <= time.Minute*4
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if systemJustBooted {
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maxTries *= 4
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}
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for i := 0; i < maxTries; i++ {
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if i > 0 {
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time.Sleep(time.Second * 4)
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}
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resolvedIPString, err = resolveHostnameOnce(name)
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if err == nil {
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return
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}
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if err == windows.WSATRY_AGAIN {
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log.Printf("Temporary DNS error when resolving %s, sleeping for 4 seconds", name)
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continue
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}
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var state uint32
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if err == windows.WSAHOST_NOT_FOUND && systemJustBooted && !internetGetConnectedState(&state, 0) {
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log.Printf("Host not found when resolving %s, but no Internet connection available, sleeping for 4 seconds", name)
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continue
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}
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return
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}
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return
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}
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func resolveHostnameOnce(name string) (resolvedIPString string, err error) {
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hints := windows.AddrinfoW{
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Family: windows.AF_UNSPEC,
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Socktype: windows.SOCK_DGRAM,
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Protocol: windows.IPPROTO_IP,
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}
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var result *windows.AddrinfoW
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name16, err := windows.UTF16PtrFromString(name)
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if err != nil {
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return
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}
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err = windows.GetAddrInfoW(name16, nil, &hints, &result)
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if err != nil {
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return
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}
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if result == nil {
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err = windows.WSAHOST_NOT_FOUND
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return
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}
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defer windows.FreeAddrInfoW(result)
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ipv6 := ""
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for ; result != nil; result = result.Next {
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switch result.Family {
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case windows.AF_INET:
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return (net.IP)((*syscall.RawSockaddrInet4)(unsafe.Pointer(result.Addr)).Addr[:]).String(), nil
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case windows.AF_INET6:
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if len(ipv6) != 0 {
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continue
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}
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a := (*syscall.RawSockaddrInet6)(unsafe.Pointer(result.Addr))
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ipv6 = (net.IP)(a.Addr[:]).String()
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if a.Scope_id != 0 {
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ipv6 += fmt.Sprintf("%%%d", a.Scope_id)
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}
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}
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}
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if len(ipv6) != 0 {
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return ipv6, nil
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}
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err = windows.WSAHOST_NOT_FOUND
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return
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}
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