From 4b48fd0b5f24ee8dbcb36bc7e12b9b720147840b Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Thu, 12 Oct 2023 00:08:16 +0100
Subject: [PATCH] Fix Windows TUN build

---
 src/tun/tun_windows.go | 39 +++++++++++----------------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/src/tun/tun_windows.go b/src/tun/tun_windows.go
index b3bb0c78..10fb5f1a 100644
--- a/src/tun/tun_windows.go
+++ b/src/tun/tun_windows.go
@@ -4,11 +4,10 @@
 package tun
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"log"
-	"net"
+	"net/netip"
 
 	"github.com/yggdrasil-network/yggdrasil-go/src/config"
 	"golang.org/x/sys/windows"
@@ -89,13 +88,9 @@ func (tun *TunAdapter) setupAddress(addr string) error {
 		return errors.New("Can't configure IPv6 address as TUN adapter is not present")
 	}
 	if intf, ok := tun.iface.(*wgtun.NativeTun); ok {
-		if ipaddr, ipnet, err := net.ParseCIDR(addr); err == nil {
+		if ipnet, err := netip.ParsePrefix(addr); err == nil {
 			luid := winipcfg.LUID(intf.LUID())
-			addresses := append([]net.IPNet{}, net.IPNet{
-				IP:   ipaddr,
-				Mask: ipnet.Mask,
-			})
-
+			addresses := []netip.Prefix{ipnet}
 			err := luid.SetIPAddressesForFamily(windows.AF_INET6, addresses)
 			if err == windows.ERROR_OBJECT_ALREADY_EXISTS {
 				cleanupAddressesOnDisconnectedInterfaces(windows.AF_INET6, addresses)
@@ -118,24 +113,13 @@ func (tun *TunAdapter) setupAddress(addr string) error {
  * SPDX-License-Identifier: MIT
  * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
  */
-func cleanupAddressesOnDisconnectedInterfaces(family winipcfg.AddressFamily, addresses []net.IPNet) {
+func cleanupAddressesOnDisconnectedInterfaces(family winipcfg.AddressFamily, addresses []netip.Prefix) {
 	if len(addresses) == 0 {
 		return
 	}
-	includedInAddresses := func(a net.IPNet) bool {
-		// TODO: this makes the whole algorithm O(n^2). But we can't stick net.IPNet in a Go hashmap. Bummer!
-		for _, addr := range addresses {
-			ip := addr.IP
-			if ip4 := ip.To4(); ip4 != nil {
-				ip = ip4
-			}
-			mA, _ := addr.Mask.Size()
-			mB, _ := a.Mask.Size()
-			if bytes.Equal(ip, a.IP) && mA == mB {
-				return true
-			}
-		}
-		return false
+	addrHash := make(map[netip.Addr]bool, len(addresses))
+	for i := range addresses {
+		addrHash[addresses[i].Addr()] = true
 	}
 	interfaces, err := winipcfg.GetAdaptersAddresses(family, winipcfg.GAAFlagDefault)
 	if err != nil {
@@ -146,11 +130,10 @@ func cleanupAddressesOnDisconnectedInterfaces(family winipcfg.AddressFamily, add
 			continue
 		}
 		for address := iface.FirstUnicastAddress; address != nil; address = address.Next {
-			ip := address.Address.IP()
-			ipnet := net.IPNet{IP: ip, Mask: net.CIDRMask(int(address.OnLinkPrefixLength), 8*len(ip))}
-			if includedInAddresses(ipnet) {
-				log.Printf("Cleaning up stale address %s from interface ‘%s’", ipnet.String(), iface.FriendlyName())
-				iface.LUID.DeleteIPAddress(ipnet)
+			if ip, _ := netip.AddrFromSlice(address.Address.IP()); addrHash[ip] {
+				prefix := netip.PrefixFrom(ip, int(address.OnLinkPrefixLength))
+				log.Printf("Cleaning up stale address %s from interface ‘%s’", prefix.String(), iface.FriendlyName())
+				iface.LUID.DeleteIPAddress(prefix)
 			}
 		}
 	}