From 5842bbc9f7f5f60f78d14a22ed4e99f405b0e2b4 Mon Sep 17 00:00:00 2001
From: xqzr <34030394+xqzr@users.noreply.github.com>
Date: Mon, 31 Mar 2025 05:43:22 +0800
Subject: [PATCH] Sockopt: Add Windows `V6Only`

#1677
---
 transport/internet/sockopt_windows.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/transport/internet/sockopt_windows.go b/transport/internet/sockopt_windows.go
index e1c1d25e..aa9f933b 100644
--- a/transport/internet/sockopt_windows.go
+++ b/transport/internet/sockopt_windows.go
@@ -15,6 +15,7 @@ const (
 	IPV6_UNICAST_IF = 31
 	IP_MULTICAST_IF = 9
 	IPV6_MULTICAST_IF = 9
+	IPV6_V6ONLY = 27
 )
 
 func setTFO(fd syscall.Handle, tfo int) error {
@@ -89,6 +90,11 @@ func applyInboundSocketOptions(network string, fd uintptr, config *SocketConfig)
 			}
 		}
 	}
+	if config.V6Only {
+		if err := syscall.SetsockoptInt(syscall.Handle(fd), syscall.IPPROTO_IPV6, IPV6_V6ONLY, 1); err != nil {
+			return errors.New("failed to set IPV6_V6ONLY").Base(err)
+		}
+	}
 
 	return nil
 }