Tcl

Open a Custom SSH Channel Type

Demonstrates the Chilkat Ssh.OpenCustomChannel method, which requests a channel whose application-defined type is supplied as the only argument. It returns the channel number, or -1 if the server rejects the channel. The server must implement that channel type.

Background: The SSH protocol allows vendor- and application-specific channel types beyond the standard session and direct-tcpip kinds; by convention these carry an @domain suffix to avoid name collisions. This method is the escape hatch for talking to a server that implements such a type. On rejection, inspect ChannelOpenFailCode to learn why.

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Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the Ssh.OpenCustomChannel method, which requests a custom SSH channel whose
#  application-defined type is supplied as the only argument.  It returns the channel number,
#  or -1 if the server rejects the channel.  The server must implement that channel type.

set ssh [new_CkSsh]

set sshPort 22
set success [CkSsh_Connect $ssh "ssh.example.com" $sshPort]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

#  Normally you would not hard-code the password in source.  You should instead obtain it
#  from an interactive prompt, environment variable, or a secrets vault.
set password "mySshPassword"

set success [CkSsh_AuthenticatePw $ssh "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

#  Request an application-defined channel type.  The server must support it.
set channelType "my-custom-channel@example.com"
set channelNum [CkSsh_OpenCustomChannel $ssh $channelType]
if {$channelNum < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

puts "Opened custom channel: $channelNum"

#  The channel is used with the normal channel send, receive, EOF, CLOSE, and release methods.

CkSsh_Disconnect $ssh

delete_CkSsh $ssh