From ce8929d1537f1f69a69ab68f7c90fb9b6bf475c6 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Mon, 13 Feb 2023 10:14:59 +0800
Subject: [PATCH] chore: better bind in windows

---
 component/dialer/bind_darwin.go  |  4 ++
 component/dialer/bind_linux.go   |  4 ++
 component/dialer/bind_others.go  | 12 ++++-
 component/dialer/bind_windows.go | 88 ++++++++++++++++++++++++++++++++
 component/dialer/dialer.go       | 12 -----
 5 files changed, 107 insertions(+), 13 deletions(-)
 create mode 100644 component/dialer/bind_windows.go

diff --git a/component/dialer/bind_darwin.go b/component/dialer/bind_darwin.go
index 91d74987..8e88b461 100644
--- a/component/dialer/bind_darwin.go
+++ b/component/dialer/bind_darwin.go
@@ -62,3 +62,7 @@ func bindIfaceToListenConfig(ifaceName string, lc *net.ListenConfig, _, address
 	lc.Control = bindControl(ifaceObj.Index, lc.Control)
 	return address, nil
 }
+
+func ParseNetwork(network string, addr netip.Addr) string {
+	return network
+}
diff --git a/component/dialer/bind_linux.go b/component/dialer/bind_linux.go
index ca88cb58..57a2e0c1 100644
--- a/component/dialer/bind_linux.go
+++ b/component/dialer/bind_linux.go
@@ -47,3 +47,7 @@ func bindIfaceToListenConfig(ifaceName string, lc *net.ListenConfig, _, address
 
 	return address, nil
 }
+
+func ParseNetwork(network string, addr netip.Addr) string {
+	return network
+}
diff --git a/component/dialer/bind_others.go b/component/dialer/bind_others.go
index f732b1ce..5cb2fd62 100644
--- a/component/dialer/bind_others.go
+++ b/component/dialer/bind_others.go
@@ -1,4 +1,4 @@
-//go:build !linux && !darwin
+//go:build !linux && !darwin && !windows
 
 package dialer
 
@@ -91,3 +91,13 @@ func bindIfaceToListenConfig(ifaceName string, _ *net.ListenConfig, network, add
 
 	return addr.String(), nil
 }
+
+func ParseNetwork(network string, addr netip.Addr) string {
+	// fix bindIfaceToListenConfig() force bind to an ipv4 address
+	if !strings.HasSuffix(network, "4") &&
+		!strings.HasSuffix(network, "6") &&
+		addr.Unmap().Is6() {
+		network += "6"
+	}
+	return network
+}
diff --git a/component/dialer/bind_windows.go b/component/dialer/bind_windows.go
new file mode 100644
index 00000000..87b39bc2
--- /dev/null
+++ b/component/dialer/bind_windows.go
@@ -0,0 +1,88 @@
+package dialer
+
+import (
+	"encoding/binary"
+	"net"
+	"net/netip"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/component/iface"
+)
+
+const (
+	IP_UNICAST_IF   = 31
+	IPV6_UNICAST_IF = 31
+)
+
+func bind4(handle syscall.Handle, ifaceIdx int) error {
+	var bytes [4]byte
+	binary.BigEndian.PutUint32(bytes[:], uint32(ifaceIdx))
+	idx := *(*uint32)(unsafe.Pointer(&bytes[0]))
+	return syscall.SetsockoptInt(handle, syscall.IPPROTO_IP, IP_UNICAST_IF, int(idx))
+}
+
+func bind6(handle syscall.Handle, ifaceIdx int) error {
+	return syscall.SetsockoptInt(handle, syscall.IPPROTO_IPV6, IPV6_UNICAST_IF, ifaceIdx)
+}
+
+type controlFn = func(network, address string, c syscall.RawConn) error
+
+func bindControl(ifaceIdx int, chain controlFn) controlFn {
+	return func(network, address string, c syscall.RawConn) (err error) {
+		defer func() {
+			if err == nil && chain != nil {
+				err = chain(network, address, c)
+			}
+		}()
+
+		addrPort, err := netip.ParseAddrPort(address)
+		if err == nil && !addrPort.Addr().IsGlobalUnicast() {
+			return
+		}
+
+		var innerErr error
+		err = c.Control(func(fd uintptr) {
+			handle := syscall.Handle(fd)
+			switch network {
+			case "tcp6", "udp6":
+				innerErr = bind6(handle, ifaceIdx)
+				_ = bind4(handle, ifaceIdx)
+			default:
+				innerErr = bind4(handle, ifaceIdx)
+				// try bind ipv6, if failed, ignore. it's a workaround for windows disable interface ipv6
+				_ = bind6(handle, ifaceIdx)
+			}
+		})
+
+		if innerErr != nil {
+			err = innerErr
+		}
+
+		return
+	}
+}
+
+func bindIfaceToDialer(ifaceName string, dialer *net.Dialer, _ string, _ netip.Addr) error {
+	ifaceObj, err := iface.ResolveInterface(ifaceName)
+	if err != nil {
+		return err
+	}
+
+	dialer.Control = bindControl(ifaceObj.Index, dialer.Control)
+	return nil
+}
+
+func bindIfaceToListenConfig(ifaceName string, lc *net.ListenConfig, _, address string) (string, error) {
+	ifaceObj, err := iface.ResolveInterface(ifaceName)
+	if err != nil {
+		return "", err
+	}
+
+	lc.Control = bindControl(ifaceObj.Index, lc.Control)
+	return address, nil
+}
+
+func ParseNetwork(network string, addr netip.Addr) string {
+	return network
+}
diff --git a/component/dialer/dialer.go b/component/dialer/dialer.go
index d7c0f3db..e31936e9 100644
--- a/component/dialer/dialer.go
+++ b/component/dialer/dialer.go
@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-	"runtime"
 	"strings"
 	"sync"
 
@@ -25,17 +24,6 @@ var (
 	ErrorDisableIPv6           = errors.New("IPv6 is disabled, dialer cancel")
 )
 
-func ParseNetwork(network string, addr netip.Addr) string {
-	if runtime.GOOS == "windows" { // fix bindIfaceToListenConfig() in windows force bind to an ipv4 address
-		if !strings.HasSuffix(network, "4") &&
-			!strings.HasSuffix(network, "6") &&
-			addr.Unmap().Is6() {
-			network += "6"
-		}
-	}
-	return network
-}
-
 func applyOptions(options ...Option) *option {
 	opt := &option{
 		interfaceName: DefaultInterface.Load(),