tailscale: update tailfs file and package names (#11590)

This change updates the tailfs file and package names to their new
naming convention.

Updates #tailscale/corp#16827

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>

drive/driveimpl/connlistener.go

@@ -0,0 +1,79 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package driveimpl
+
+import (
+	"log"
+	"net"
+	"sync"
+	"syscall"
+)
+
+type connListener struct {
+	ch       chan net.Conn
+	closedCh chan any
+	closeMu  sync.Mutex
+}
+
+// newConnListener creates a net.Listener to which one can hand connections
+// directly.
+func newConnListener() *connListener {
+	return &connListener{
+		ch:       make(chan net.Conn),
+		closedCh: make(chan any),
+	}
+}
+
+func (l *connListener) Accept() (net.Conn, error) {
+	select {
+	case <-l.closedCh:
+		// TODO(oxtoacart): make this error match what a regular net.Listener does
+		return nil, syscall.EINVAL
+	case conn := <-l.ch:
+		return conn, nil
+	}
+}
+
+// Addr implements net.Listener. This always returns nil. It is assumed that
+// this method is currently unused, so it logs a warning if it ever does get
+// called.
+func (l *connListener) Addr() net.Addr {
+	log.Println("warning: unexpected call to connListener.Addr()")
+	return nil
+}
+
+func (l *connListener) Close() error {
+	l.closeMu.Lock()
+	defer l.closeMu.Unlock()
+
+	select {
+	case <-l.closedCh:
+		// Already closed.
+		return syscall.EINVAL
+	default:
+		// We don't close l.ch because someone maybe trying to send to that,
+		// which would cause a panic.
+		close(l.closedCh)
+		return nil
+	}
+}
+
+func (l *connListener) HandleConn(c net.Conn, remoteAddr net.Addr) error {
+	select {
+	case <-l.closedCh:
+		return syscall.EINVAL
+	case l.ch <- &connWithRemoteAddr{Conn: c, remoteAddr: remoteAddr}:
+		// Connection has been accepted.
+	}
+	return nil
+}
+
+type connWithRemoteAddr struct {
+	net.Conn
+	remoteAddr net.Addr
+}
+
+func (c *connWithRemoteAddr) RemoteAddr() net.Addr {
+	return c.remoteAddr
+}