1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"errors"
"fmt"
"io"
"net"
)
// Dial initiates a connection to the addr from the remote host.
// addr is resolved using net.ResolveTCPAddr before connection.
// This could allow an observer to observe the DNS name of the
// remote host. Consider using ssh.DialTCP to avoid this.
func (c *ClientConn) Dial(n, addr string) (net.Conn, error) {
raddr, err := net.ResolveTCPAddr(n, addr)
if err != nil {
return nil, err
}
return c.DialTCP(n, nil, raddr)
}
// DialTCP connects to the remote address raddr on the network net,
// which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used
// as the local address for the connection.
func (c *ClientConn) DialTCP(n string, laddr, raddr *net.TCPAddr) (net.Conn, error) {
if laddr == nil {
laddr = &net.TCPAddr{
IP: net.IPv4zero,
Port: 0,
}
}
ch, err := c.dial(laddr.IP.String(), laddr.Port, raddr.IP.String(), raddr.Port)
if err != nil {
return nil, err
}
return &tcpchanconn{
tcpchan: ch,
laddr: laddr,
raddr: raddr,
}, nil
}
// RFC 4254 7.2
type channelOpenDirectMsg struct {
ChanType string
PeersId uint32
PeersWindow uint32
MaxPacketSize uint32
raddr string
rport uint32
laddr string
lport uint32
}
// dial opens a direct-tcpip connection to the remote server. laddr and raddr are passed as
// strings and are expected to be resolveable at the remote end.
func (c *ClientConn) dial(laddr string, lport int, raddr string, rport int) (*tcpchan, error) {
ch := c.newChan(c.transport)
if err := c.writePacket(marshal(msgChannelOpen, channelOpenDirectMsg{
ChanType: "direct-tcpip",
PeersId: ch.id,
PeersWindow: 1 << 14,
MaxPacketSize: 1 << 15, // RFC 4253 6.1
raddr: raddr,
rport: uint32(rport),
laddr: laddr,
lport: uint32(lport),
})); err != nil {
c.chanlist.remove(ch.id)
return nil, err
}
if err := ch.waitForChannelOpenResponse(); err != nil {
c.chanlist.remove(ch.id)
return nil, fmt.Errorf("ssh: unable to open direct tcpip connection: %v", err)
}
return &tcpchan{
clientChan: ch,
Reader: ch.stdout,
Writer: ch.stdin,
}, nil
}
type tcpchan struct {
*clientChan // the backing channel
io.Reader
io.Writer
}
// tcpchanconn fulfills the net.Conn interface without
// the tcpchan having to hold laddr or raddr directly.
type tcpchanconn struct {
*tcpchan
laddr, raddr net.Addr
}
// LocalAddr returns the local network address.
func (t *tcpchanconn) LocalAddr() net.Addr {
return t.laddr
}
// RemoteAddr returns the remote network address.
func (t *tcpchanconn) RemoteAddr() net.Addr {
return t.raddr
}
// SetTimeout sets the read and write deadlines associated
// with the connection.
func (t *tcpchanconn) SetTimeout(nsec int64) error {
if err := t.SetReadTimeout(nsec); err != nil {
return err
}
return t.SetWriteTimeout(nsec)
}
// SetReadTimeout sets the time (in nanoseconds) that
// Read will wait for data before returning an error with Timeout() == true.
// Setting nsec == 0 (the default) disables the deadline.
func (t *tcpchanconn) SetReadTimeout(nsec int64) error {
return errors.New("ssh: tcpchan: timeout not supported")
}
// SetWriteTimeout sets the time (in nanoseconds) that
// Write will wait to send its data before returning an error with Timeout() == true.
// Setting nsec == 0 (the default) disables the deadline.
// Even if write times out, it may return n > 0, indicating that
// some of the data was successfully written.
func (t *tcpchanconn) SetWriteTimeout(nsec int64) error {
return errors.New("ssh: tcpchan: timeout not supported")
}
|