From: Josh Bleecher Snyder <josh@tailscale.com>
Date: Mon, 14 Dec 2020 21:34:03 +0000 (-0800)
Subject: device: prevent spurious errors while closing a device
X-Git-Tag: 0.0.20210212~132
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fc0aabbae94f8da498c8fab89b833b4e7a3abab6;p=thirdparty%2Fwireguard-go.git

device: prevent spurious errors while closing a device

When closing a device, packets that are in flight
can make it to SendBuffer, which then returns an error.
Those errors add noise but no light;
they do not reflect an actual problem.

Adding the synchronization required to prevent
this from occurring is currently expensive and error-prone.
Instead, quietly drop such packets instead of
returning an error.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
---

diff --git a/device/peer.go b/device/peer.go
index 02e145c..c2397cc 100644
--- a/device/peer.go
+++ b/device/peer.go
@@ -140,6 +140,11 @@ func (peer *Peer) SendBuffer(buffer []byte) error {
 	defer peer.device.net.RUnlock()
 
 	if peer.device.net.bind == nil {
+		// Packets can leak through to SendBuffer while the device is closing.
+		// When that happens, drop them silently to avoid spurious errors.
+		if peer.device.isClosed.Get() {
+			return nil
+		}
 		return errors.New("no bind")
 	}