Feature: support bind interface on windows (#192)

component/dialer/sockopt_others.go

@@ -1,4 +1,4 @@
-//go:build !linux && !darwin
+//go:build !linux && !darwin && !windows
 
 package dialer
 

component/dialer/sockopt_windows.go

@@ -0,0 +1,68 @@
+package dialer
+
+import (
+	"encoding/binary"
+	"net"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+const (
+	IP_UNICAST_IF   = 31
+	IPV6_UNICAST_IF = 31
+)
+
+func setSocketOptions(network, address string, c syscall.RawConn, opts *Options) (err error) {
+	if opts == nil || !isTCPSocket(network) && !isUDPSocket(network) {
+		return
+	}
+
+	var innerErr error
+	err = c.Control(func(fd uintptr) {
+		host, _, _ := net.SplitHostPort(address)
+		ip := net.ParseIP(host)
+		if ip != nil && !ip.IsGlobalUnicast() {
+			return
+		}
+
+		if opts.InterfaceIndex == 0 && opts.InterfaceName != "" {
+			if iface, err := net.InterfaceByName(opts.InterfaceName); err == nil {
+				opts.InterfaceIndex = iface.Index
+			}
+		}
+
+		if opts.InterfaceIndex != 0 {
+			switch network {
+			case "tcp4", "udp4":
+				innerErr = bindSocketToInterface4(windows.Handle(fd), uint32(opts.InterfaceIndex))
+			case "tcp6", "udp6":
+				innerErr = bindSocketToInterface6(windows.Handle(fd), uint32(opts.InterfaceIndex))
+				if network == "udp6" && ip == nil {
+					// The underlying IP net maybe IPv4 even if the `network` param is `udp6`,
+					// so we should bind socket to interface4 at the same time.
+					innerErr = bindSocketToInterface4(windows.Handle(fd), uint32(opts.InterfaceIndex))
+				}
+			}
+		}
+	})
+
+	if innerErr != nil {
+		err = innerErr
+	}
+	return
+}
+
+func bindSocketToInterface4(handle windows.Handle, index uint32) error {
+	// For IPv4, this parameter must be an interface index in network byte order.
+	// Ref: https://learn.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options
+	var bytes [4]byte
+	binary.BigEndian.PutUint32(bytes[:], index)
+	index = *(*uint32)(unsafe.Pointer(&bytes[0]))
+	return windows.SetsockoptInt(handle, windows.IPPROTO_IP, IP_UNICAST_IF, int(index))
+}
+
+func bindSocketToInterface6(handle windows.Handle, index uint32) error {
+	return windows.SetsockoptInt(handle, windows.IPPROTO_IPV6, IPV6_UNICAST_IF, int(index))
+}