conn: bump to 1.16 and get rid of NetErrClosed hack

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

conn/conn_linux.go

@@ -213,7 +213,7 @@ func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 
 	var end NativeEndpoint
 	if bind.sock6 == -1 {
-		return 0, nil, NetErrClosed
+		return 0, nil, net.ErrClosed
 	}
 	n, err := receive6(
 		bind.sock6,
@@ -229,7 +229,7 @@ func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 
 	var end NativeEndpoint
 	if bind.sock4 == -1 {
-		return 0, nil, NetErrClosed
+		return 0, nil, net.ErrClosed
 	}
 	n, err := receive4(
 		bind.sock4,
@@ -246,12 +246,12 @@ func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
 	nend := end.(*NativeEndpoint)
 	if !nend.isV6 {
 		if bind.sock4 == -1 {
-			return NetErrClosed
+			return net.ErrClosed
 		}
 		return send4(bind.sock4, nend, buff)
 	} else {
 		if bind.sock6 == -1 {
-			return NetErrClosed
+			return net.ErrClosed
 		}
 		return send6(bind.sock6, nend, buff)
 	}

conn/net_err_closed.go

@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
- */
-
-package conn
-
-import _ "unsafe"
-
-//TODO: replace this with net.ErrClosed for Go 1.16
-
-//go:linkname NetErrClosed internal/poll.ErrNetClosing
-var NetErrClosed error

device/receive.go

@@ -101,7 +101,7 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind conn.Bind) {
 
 		if err != nil {
 			device.PutMessageBuffer(buffer)
-			if errors.Is(err, conn.NetErrClosed) {
+			if errors.Is(err, net.ErrClosed) {
 				return
 			}
 			device.log.Errorf("Failed to receive packet: %v", err)

go.mod

@@ -1,6 +1,6 @@
 module golang.zx2c4.com/wireguard
 
-go 1.15
+go 1.16
 
 require (
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad