From b39592f68a29e0d0dfd91045def1a7cf1b014ba1 Mon Sep 17 00:00:00 2001
From: Denton Gentry <dgentry@tailscale.com>
Date: Fri, 10 Jun 2022 22:13:24 -0700
Subject: [PATCH] net/portmapper: make pcpCodeNotAuthorized log more
 descriptive

If PCP is present but disabled, turning it on might help
get direct connections.

Signed-off-by: Denton Gentry <dgentry@tailscale.com>
(cherry picked from commit de4c635e54b81bea223d00f97e043c6abd2e54ff)
---
 net/portmapper/pcp.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/portmapper/pcp.go b/net/portmapper/pcp.go
index 43417947e..66b93845c 100644
--- a/net/portmapper/pcp.go
+++ b/net/portmapper/pcp.go
@@ -115,6 +115,9 @@ func parsePCPMapResponse(resp []byte) (*pcpMapping, error) {
 	if !ok {
 		return nil, fmt.Errorf("Invalid PCP common header")
 	}
+	if res.ResultCode == pcpCodeNotAuthorized {
+		return nil, fmt.Errorf("PCP is implemented but not enabled in the router")
+	}
 	if res.ResultCode != pcpCodeOK {
 		return nil, fmt.Errorf("PCP response not ok, code %d", res.ResultCode)
 	}