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// 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")
}
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