1package ssh
2
3import (
4	"errors"
5	"io"
6	"net"
7)
8
9// streamLocalChannelOpenDirectMsg is a struct used for SSH_MSG_CHANNEL_OPEN message
10// with "direct-streamlocal@openssh.com" string.
11//
12// See openssh-portable/PROTOCOL, section 2.4. connection: Unix domain socket forwarding
13// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL#L235
14type streamLocalChannelOpenDirectMsg struct {
15	socketPath string
16	reserved0  string
17	reserved1  uint32
18}
19
20// forwardedStreamLocalPayload is a struct used for SSH_MSG_CHANNEL_OPEN message
21// with "forwarded-streamlocal@openssh.com" string.
22type forwardedStreamLocalPayload struct {
23	SocketPath string
24	Reserved0  string
25}
26
27// streamLocalChannelForwardMsg is a struct used for SSH2_MSG_GLOBAL_REQUEST message
28// with "streamlocal-forward@openssh.com"/"cancel-streamlocal-forward@openssh.com" string.
29type streamLocalChannelForwardMsg struct {
30	socketPath string
31}
32
33// ListenUnix is similar to ListenTCP but uses a Unix domain socket.
34func (c *Client) ListenUnix(socketPath string) (net.Listener, error) {
35	m := streamLocalChannelForwardMsg{
36		socketPath,
37	}
38	// send message
39	ok, _, err := c.SendRequest("streamlocal-forward@openssh.com", true, Marshal(&m))
40	if err != nil {
41		return nil, err
42	}
43	if !ok {
44		return nil, errors.New("ssh: streamlocal-forward@openssh.com request denied by peer")
45	}
46	ch := c.forwards.add(&net.UnixAddr{Name: socketPath, Net: "unix"})
47
48	return &unixListener{socketPath, c, ch}, nil
49}
50
51func (c *Client) dialStreamLocal(socketPath string) (Channel, error) {
52	msg := streamLocalChannelOpenDirectMsg{
53		socketPath: socketPath,
54	}
55	ch, in, err := c.OpenChannel("direct-streamlocal@openssh.com", Marshal(&msg))
56	if err != nil {
57		return nil, err
58	}
59	go DiscardRequests(in)
60	return ch, err
61}
62
63type unixListener struct {
64	socketPath string
65
66	conn *Client
67	in   <-chan forward
68}
69
70// Accept waits for and returns the next connection to the listener.
71func (l *unixListener) Accept() (net.Conn, error) {
72	s, ok := <-l.in
73	if !ok {
74		return nil, io.EOF
75	}
76	ch, incoming, err := s.newCh.Accept()
77	if err != nil {
78		return nil, err
79	}
80	go DiscardRequests(incoming)
81
82	return &chanConn{
83		Channel: ch,
84		laddr: &net.UnixAddr{
85			Name: l.socketPath,
86			Net:  "unix",
87		},
88		raddr: &net.UnixAddr{
89			Name: "@",
90			Net:  "unix",
91		},
92	}, nil
93}
94
95// Close closes the listener.
96func (l *unixListener) Close() error {
97	// this also closes the listener.
98	l.conn.forwards.remove(&net.UnixAddr{Name: l.socketPath, Net: "unix"})
99	m := streamLocalChannelForwardMsg{
100		l.socketPath,
101	}
102	ok, _, err := l.conn.SendRequest("cancel-streamlocal-forward@openssh.com", true, Marshal(&m))
103	if err == nil && !ok {
104		err = errors.New("ssh: cancel-streamlocal-forward@openssh.com failed")
105	}
106	return err
107}
108
109// Addr returns the listener's network address.
110func (l *unixListener) Addr() net.Addr {
111	return &net.UnixAddr{
112		Name: l.socketPath,
113		Net:  "unix",
114	}
115}
116