From ac3638f6b1f2ca6f4c20ca32fa8fba4c1a00fefa Mon Sep 17 00:00:00 2001
From: Igor Postelnik <igor@cloudflare.com>
Date: Tue, 7 Jul 2020 16:35:44 -0500
Subject: [PATCH] TUN-3169: Move on to the next address when edge returns
 duplicate connection. There's no point in trying to connect to the same
 address since it will be hashed to the same metal. Improve logging of errors
 from serve tunnel loop, hide useless context cancelled error.

---
 origin/tunnel.go | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/origin/tunnel.go b/origin/tunnel.go
index ce463a4f..fcd206ab 100644
--- a/origin/tunnel.go
+++ b/origin/tunnel.go
@@ -105,7 +105,7 @@ type dupConnRegisterTunnelError struct{}
 var errDuplicationConnection = &dupConnRegisterTunnelError{}
 
 func (e dupConnRegisterTunnelError) Error() string {
-	return "already connected to this server"
+	return "already connected to this server, trying another address"
 }
 
 type muxerShutdownError struct{}
@@ -376,29 +376,33 @@ func ServeTunnel(
 
 	err = errGroup.Wait()
 	if err != nil {
-		switch castedErr := err.(type) {
-		case dupConnRegisterTunnelError:
-			logger.Info("Already connected to this server, selecting a different one")
-			return err, true
-		case serverRegisterTunnelError:
-			logger.Errorf("Register tunnel error from server side: %s", castedErr.cause)
+		switch err := err.(type) {
+		case *dupConnRegisterTunnelError:
+			// don't retry this connection anymore, let supervisor pick new a address
+			return err, false
+		case *serverRegisterTunnelError:
+			logger.Errorf("Register tunnel error from server side: %s", err.cause)
 			// Don't send registration error return from server to Sentry. They are
 			// logged on server side
 			if incidents := config.IncidentLookup.ActiveIncidents(); len(incidents) > 0 {
 				logger.Error(activeIncidentsMsg(incidents))
 			}
-			return castedErr.cause, !castedErr.permanent
-		case clientRegisterTunnelError:
-			logger.Errorf("Register tunnel error on client side: %s", castedErr.cause)
+			return err.cause, !err.permanent
+		case *clientRegisterTunnelError:
+			logger.Errorf("Register tunnel error on client side: %s", err.cause)
 			return err, true
-		case muxerShutdownError:
+		case *muxerShutdownError:
 			logger.Info("Muxer shutdown")
 			return err, true
 		case *ReconnectSignal:
-			logger.Infof("Restarting connection %d due to reconnect signal in %d seconds", connectionIndex, castedErr.Delay)
-			castedErr.DelayBeforeReconnect()
+			logger.Infof("Restarting connection %d due to reconnect signal in %d seconds", connectionIndex, err.Delay)
+			err.DelayBeforeReconnect()
 			return err, true
 		default:
+			if err == context.Canceled {
+				logger.Debugf("Serve tunnel error: %s", err)
+				return err, false
+			}
 			logger.Errorf("Serve tunnel error: %s", err)
 			return err, true
 		}