Update

vendor/tailscale.com/net/neterror/neterror.go

@@ -1,4 +1,4 @@
-// Copyright (c) Tailscale Inc & AUTHORS
+// Copyright (c) Tailscale Inc & contributors
 // SPDX-License-Identifier: BSD-3-Clause
 
 // Package neterror classifies network errors.
@@ -50,8 +50,8 @@ var packetWasTruncated func(error) bool // non-nil on Windows at least
 // size and an error are returned (as per the partial fix for golang/go#14074).
 // If the WSAEMSGSIZE error is returned, then we ignore the error to get
 // semantics similar to the POSIX operating systems. One caveat is that it
-// appears that the source address is not returned when WSAEMSGSIZE occurs, but
-// we do not currently look at the source address.
+// appears that the source address is not returned when WSAEMSGSIZE occurs, so
+// a caller can't check where a truncated datagram came from.
 func PacketWasTruncated(err error) bool {
 	if packetWasTruncated == nil {
 		return false

vendor/tailscale.com/net/neterror/neterror_js.go

@@ -0,0 +1,20 @@
+// Copyright (c) Tailscale Inc & contributors
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build js || wasip1 || wasm
+
+package neterror
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+)
+
+// Reports whether err resulted from reading or writing to a closed or broken pipe.
+func IsClosedPipeError(err error) bool {
+	// Libraries may also return root errors like fs.ErrClosed/io.ErrClosedPipe
+	// due to a closed socket.
+	return errors.Is(err, fs.ErrClosed) ||
+		errors.Is(err, io.ErrClosedPipe)
+}

vendor/tailscale.com/net/neterror/neterror_linux.go

@@ -1,4 +1,4 @@
-// Copyright (c) Tailscale Inc & AUTHORS
+// Copyright (c) Tailscale Inc & contributors
 // SPDX-License-Identifier: BSD-3-Clause
 
 package neterror
@@ -12,8 +12,7 @@ import (
 
 func init() {
 	shouldDisableUDPGSO = func(err error) bool {
-		var serr *os.SyscallError
-		if errors.As(err, &serr) {
+		if serr, ok := errors.AsType[*os.SyscallError](err); ok {
 			// EIO is returned by udp_send_skb() if the device driver does not
 			// have tx checksumming enabled, which is a hard requirement of
 			// UDP_SEGMENT. See:

vendor/tailscale.com/net/neterror/neterror_plan9.go

@@ -0,0 +1,24 @@
+// Copyright (c) Tailscale Inc & contributors
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build plan9
+
+package neterror
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"strings"
+)
+
+// Reports whether err resulted from reading or writing to a closed or broken pipe.
+func IsClosedPipeError(err error) bool {
+	// Libraries may also return root errors like fs.ErrClosed/io.ErrClosedPipe
+	// due to a closed socket.
+	// For a raw syscall error, check for error string containing "closed pipe",
+	// per the note set by the system: https://9p.io/magic/man2html/2/pipe
+	return errors.Is(err, fs.ErrClosed) ||
+		errors.Is(err, io.ErrClosedPipe) ||
+		strings.Contains(err.Error(), "closed pipe")
+}

vendor/tailscale.com/net/neterror/neterror_posix.go

@@ -0,0 +1,32 @@
+// Copyright (c) Tailscale Inc & contributors
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9 && !js && !wasip1 && !wasm
+
+package neterror
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"runtime"
+	"syscall"
+)
+
+// Reports whether err resulted from reading or writing to a closed or broken pipe.
+func IsClosedPipeError(err error) bool {
+	// 232 is Windows error code ERROR_NO_DATA, "The pipe is being closed".
+	if runtime.GOOS == "windows" && errors.Is(err, syscall.Errno(232)) {
+		return true
+	}
+
+	// EPIPE/ENOTCONN are common errors when a send fails due to a closed
+	// socket. There is some platform and version inconsistency in which
+	// error is returned, but the meaning is the same.
+	// Libraries may also return root errors like fs.ErrClosed/io.ErrClosedPipe
+	// due to a closed socket.
+	return errors.Is(err, syscall.EPIPE) ||
+		errors.Is(err, syscall.ENOTCONN) ||
+		errors.Is(err, fs.ErrClosed) ||
+		errors.Is(err, io.ErrClosedPipe)
+}

vendor/tailscale.com/net/neterror/neterror_windows.go

@@ -1,4 +1,4 @@
-// Copyright (c) Tailscale Inc & AUTHORS
+// Copyright (c) Tailscale Inc & contributors
 // SPDX-License-Identifier: BSD-3-Clause
 
 package neterror