From a4286562801a33c66df8468f25732b4c7acdf412 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Thu, 28 May 2020 14:16:23 -0700
Subject: [PATCH] wgengine/magicsock: don't report v4 localhost addresses on
 IPv6-only systems

Updates #376
---
 wgengine/magicsock/magicsock.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index aeaafeec6..230ee3a2b 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -547,9 +547,10 @@ func (c *Conn) determineEndpoints(ctx context.Context) (ipPorts []string, reason
 			return nil, nil, err
 		}
 		reason := "localAddresses"
-		if len(ips) == 0 {
+		if len(ips) == 0 && len(eps) == 0 {
 			// Only include loopback addresses if we have no
-			// interfaces at all to use as endpoints. This allows
+			// interfaces at all to use as endpoints and don't
+			// have a public IPv4 or IPv6 address. This allows
 			// for localhost testing when you're on a plane and
 			// offline, for example.
 			ips = loopback