From a87ee4168a5e67a08b3f8d4b4f3c3c5a0f98190f Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Thu, 12 Mar 2020 14:14:23 -0700
Subject: [PATCH] stunner: quiet a harmless log warning

---
 stunner/stunner.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/stunner/stunner.go b/stunner/stunner.go
index d3c480528..00e8318a9 100644
--- a/stunner/stunner.go
+++ b/stunner/stunner.go
@@ -105,6 +105,11 @@ func (s *Stunner) Receive(p []byte, fromAddr *net.UDPAddr) {
 	now := time.Now()
 	tx, addr, port, err := stun.ParseResponse(p)
 	if err != nil {
+		if _, err := stun.ParseBindingRequest(p); err == nil {
+			// This was probably our own netcheck hairpin
+			// check probe coming in late. Ignore.
+			return
+		}
 		s.logf("stunner: received bad STUN response: %v", err)
 		return
 	}