netlink: add func AddrSubscribe on windows

netlink/addr_windows.go

@@ -0,0 +1,31 @@
+package netlink
+
+import (
+	"context"
+	"net"
+	"slices"
+
+	"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
+)
+
+func AddrSubscribe(ctx context.Context, ch chan<- AddrUpdate) error {
+	cb, err := winipcfg.RegisterUnicastAddressChangeCallback(func(notificationType winipcfg.MibNotificationType, addr *winipcfg.MibUnicastIPAddressRow) {
+		if !slices.Contains([]winipcfg.MibNotificationType{winipcfg.MibAddInstance, winipcfg.MibDeleteInstance}, notificationType) {
+			return
+		}
+		ch <- AddrUpdate{
+			New:       notificationType == winipcfg.MibAddInstance,
+			Addr:      net.IPNet{IP: net.ParseIP(addr.Address.Addr().String())},
+			LinkIndex: int(addr.InterfaceIndex),
+		}
+	})
+	if err != nil {
+		return err
+	}
+	go func() {
+		<-ctx.Done()
+		cb.Unregister()
+		close(ch)
+	}()
+	return nil
+}