SSH Tunnel (Port Forwarding via direct-tcpip Channel)

See more SSH Examples

Demonstrates creating an SSH tunnel to a remote host:port using a direct-tcpip channel. Data written to the channel is forwarded by the SSH server to the target, and data read back is whatever the target sent. This example tunnels a simple HTTP GET request to a web server.

integer li_rc
integer li_Success
oleobject loo_Ssh
string ls_Hostname
integer li_Port
string ls_Password
string ls_TargetHost
integer li_TargetPort
integer li_ChannelNum
string ls_HttpReq
integer li_CaseSensitive
string ls_MatchStr
string ls_ResponseHeader
integer li_PollTimeoutMs
integer li_NumBytesRead
string ls_HtmlBody

li_Success = 0

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  Demonstrates creating an SSH tunnel to a remote host:port using a direct-tcpip channel.
//  Data written to the channel is forwarded by the SSH server to the target host:port, and data
//  read from the channel is whatever the target sent back.

loo_Ssh = create oleobject
li_rc = loo_Ssh.ConnectToNewObject("Chilkat.Ssh")
if li_rc < 0 then
    destroy loo_Ssh
    MessageBox("Error","Connecting to COM object failed")
    return
end if

ls_Hostname = "ssh.example.com"
li_Port = 22
li_Success = loo_Ssh.Connect(ls_Hostname,li_Port)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  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.
ls_Password = "mySshPassword"

li_Success = loo_Ssh.AuthenticatePw("mySshLogin",ls_Password)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  Ask the SSH server to connect onward to this host:port.  The target is resolved by the SSH
//  server, not by this computer, so it must be reachable from the server's network.  The target
//  need not be a web server -- it can be any TCP service.
ls_TargetHost = "www.chilkatsoft.com"
li_TargetPort = 80
li_ChannelNum = loo_Ssh.OpenDirectTcpIpChannel(ls_TargetHost,li_TargetPort)
if li_ChannelNum < 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  Send a simple HTTP GET request through the tunnel.
ls_HttpReq = "GET /xyz123.html HTTP/1.1~r~nHost: www.chilkatsoft.com~r~n~r~n"
li_Success = loo_Ssh.ChannelSendString(li_ChannelNum,ls_HttpReq,"utf-8")
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
//  which means no limit -- without it, this call waits forever if the received data never
//  contains a match.
loo_Ssh.ReadTimeoutMs = 15000

//  An HTTP response header ends with a blank line, so receive until a double CRLF is seen.
//  The method may read beyond the match, but it stops waiting as soon as the match appears.
li_CaseSensitive = 0
ls_MatchStr = "~r~n~r~n"
li_Success = loo_Ssh.ChannelReceiveUntilMatch(li_ChannelNum,ls_MatchStr,"utf-8",li_CaseSensitive)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  GetReceivedTextS removes everything through and including the match, which is exactly the
//  response header.
ls_ResponseHeader = loo_Ssh.GetReceivedTextS(li_ChannelNum,ls_MatchStr,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

Write-Debug "---- HTTP Response Header ----"
Write-Debug ls_ResponseHeader

//  The body may already have arrived along with the header.  Poll briefly for anything more.
//  A -2 return simply means nothing further arrived, which is not an error here.
li_PollTimeoutMs = 200
li_NumBytesRead = loo_Ssh.ChannelPoll(li_ChannelNum,li_PollTimeoutMs)
if li_NumBytesRead = -1 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

ls_HtmlBody = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

Write-Debug "---- HTML BODY ----"
Write-Debug ls_HtmlBody

li_Success = loo_Ssh.ChannelSendClose(li_ChannelNum)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

loo_Ssh.Disconnect()


destroy loo_Ssh