device: fix error shadowing before log print

bradfitz · zx2c4 · commit 9c4bcedf80ee · 2020-12-17T12:15:14.000+01:00
Signed-off-by: Brad Fitzpatrick &lt;bradfitz@tailscale.com&gt;
diff --git a/device/receive.go b/device/receive.go
@@ -633,14 +633,14 @@ func (peer *Peer) RoutineSequentialReceiver() {
 
 		offset := MessageTransportOffsetContent
 		_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)
+		if err != nil && !device.isClosed.Get() {
+			logError.Println("Failed to write packet to TUN device:", err)
+		}
 		if len(peer.queue.inbound) == 0 {
-			err = device.tun.device.Flush()
+			err := device.tun.device.Flush()
 			if err != nil {
 				peer.device.log.Error.Printf("Unable to flush packets: %v", err)
 			}
 		}
-		if err != nil && !device.isClosed.Get() {
-			logError.Println("Failed to write packet to TUN device:", err)
-		}
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -633,14 +633,14 @@ func (peer *Peer) RoutineSequentialReceiver() {`
`633`	`633`
`634`	`634`	`offset := MessageTransportOffsetContent`
`635`	`635`	`_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)`
	`636`	`+ if err != nil && !device.isClosed.Get() {`
	`637`	`+ logError.Println("Failed to write packet to TUN device:", err)`
	`638`	`+ }`
`636`	`639`	`if len(peer.queue.inbound) == 0 {`
`637`		`- err = device.tun.device.Flush()`
	`640`	`+ err := device.tun.device.Flush()`
`638`	`641`	`if err != nil {`
`639`	`642`	`peer.device.log.Error.Printf("Unable to flush packets: %v", err)`
`640`	`643`	`}`
`641`	`644`	`}`
`642`		`- if err != nil && !device.isClosed.Get() {`
`643`		`- logError.Println("Failed to write packet to TUN device:", err)`
`644`		`- }`
`645`	`645`	`}`
`646`	`646`	`}`