Update dependencies

vendor/tailscale.com/net/netutil/netutil.go

@@ -0,0 +1,111 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package netutil contains misc shared networking code & types.
+package netutil
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"sync"
+)
+
+// NewOneConnListener returns a net.Listener that returns c on its
+// first Accept and EOF thereafter.
+//
+// The returned Listener's Addr method returns addr if non-nil. If nil,
+// Addr returns a non-nil dummy address instead.
+func NewOneConnListener(c net.Conn, addr net.Addr) net.Listener {
+	if addr == nil {
+		addr = dummyAddr("one-conn-listener")
+	}
+	return &oneConnListener{
+		addr: addr,
+		conn: c,
+	}
+}
+
+type oneConnListener struct {
+	addr net.Addr
+
+	mu   sync.Mutex
+	conn net.Conn
+}
+
+func (ln *oneConnListener) Accept() (c net.Conn, err error) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+	c = ln.conn
+	if c == nil {
+		err = io.EOF
+		return
+	}
+	err = nil
+	ln.conn = nil
+	return
+}
+
+func (ln *oneConnListener) Addr() net.Addr { return ln.addr }
+
+func (ln *oneConnListener) Close() error {
+	ln.Accept() // guarantee future call returns io.EOF
+	return nil
+}
+
+type dummyAddr string
+
+func (a dummyAddr) Network() string { return string(a) }
+func (a dummyAddr) String() string  { return string(a) }
+
+// NewDrainBufConn returns a net.Conn conditionally wrapping c,
+// prefixing any bytes that are in initialReadBuf, which may be nil.
+func NewDrainBufConn(c net.Conn, initialReadBuf *bufio.Reader) net.Conn {
+	r := initialReadBuf
+	if r != nil && r.Buffered() == 0 {
+		r = nil
+	}
+	return &drainBufConn{c, r}
+}
+
+// drainBufConn is a net.Conn with an initial bunch of bytes in a
+// bufio.Reader. Read drains the bufio.Reader until empty, then passes
+// through subsequent reads to the Conn directly.
+type drainBufConn struct {
+	net.Conn
+	r *bufio.Reader
+}
+
+func (b *drainBufConn) Read(bs []byte) (int, error) {
+	if b.r == nil {
+		return b.Conn.Read(bs)
+	}
+	n, err := b.r.Read(bs)
+	if b.r.Buffered() == 0 {
+		b.r = nil
+	}
+	return n, err
+}
+
+// NewAltReadWriteCloserConn returns a net.Conn that wraps rwc (for
+// Read, Write, and Close) and c (for all other methods).
+func NewAltReadWriteCloserConn(rwc io.ReadWriteCloser, c net.Conn) net.Conn {
+	return wrappedConn{c, rwc}
+}
+
+type wrappedConn struct {
+	net.Conn
+	rwc io.ReadWriteCloser
+}
+
+func (w wrappedConn) Read(bs []byte) (int, error) {
+	return w.rwc.Read(bs)
+}
+
+func (w wrappedConn) Write(bs []byte) (int, error) {
+	return w.rwc.Write(bs)
+}
+
+func (w wrappedConn) Close() error {
+	return w.rwc.Close()
+}