From 0ee1146e1c996e9056c9ae0af71a6cec4cf9388b Mon Sep 17 00:00:00 2001
From: AudriusButkevicius <audrius.butkevicius@gmail.com>
Date: Tue, 7 Nov 2017 07:25:05 +0000
Subject: [PATCH] lib/connections:  Indicate stack in transport (fixes #4463)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4486
---
 lib/connections/structs.go | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/connections/structs.go b/lib/connections/structs.go
index 0a044d0b..7e678a8c 100644
--- a/lib/connections/structs.go
+++ b/lib/connections/structs.go
@@ -93,7 +93,19 @@ func (c internalConn) Type() string {
 }
 
 func (c internalConn) Transport() string {
-	return c.connType.Transport()
+	transport := c.connType.Transport()
+	host, _, err := net.SplitHostPort(c.LocalAddr().String())
+	if err != nil {
+		return transport
+	}
+	ip := net.ParseIP(host)
+	if ip == nil {
+		return transport
+	}
+	if ip.To4() != nil {
+		return transport + "4"
+	}
+	return transport + "6"
 }
 
 func (c internalConn) String() string {