Tcl

SSH Tunnel (Port Forwarding via direct-tcpip channel)

See more SSH Examples

Demonstrates how to create an SSH tunnel to a remote hostname:port via a direct-tcpip channel. Tcl

load ./chilkat.dll

set success 0

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

set ssh [new_CkSsh]

# Connect to an SSH server:

# Hostname may be an IP address or hostname:
set hostname "192.168.1.117"
set port 22

set success [CkSsh_Connect $ssh $hostname $port]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Wait a max of 5 seconds when reading responses..
CkSsh_put_IdleTimeoutMs $ssh 5000

# Authenticate using login/password:
set success [CkSsh_AuthenticatePw $ssh "chilkat" "myPassword"]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Open a direct-tcpip channel.  We want the SSH server to connect
# to www.chilkatsoft.com, port 80 (i.e. the web server).
# Data sent through the SSH tunnel is forwarded to the remote
# host:port.  (Note: The remote host:port does not need to be 
# a web server.  It can be anything.  It can be your own
# customer application server that listens on a port, or any
# other type of server.)
# When we read from the SSH channel, we'll be reading data
# sent from the remote host:port (i.e. the web server in this
# example).

set channelNum [CkSsh_OpenDirectTcpIpChannel $ssh "www.chilkatsoft.com" 80]
if {$channelNum < 0} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Build a simple HTTP GET request for http://www.chilkatsoft.com/xyz.html
set httpReq "GET /xyz123.html HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n"

# Send the HTTP request:
set success [CkSsh_ChannelSendString $ssh $channelNum $httpReq "ansi"]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Get the HTTP response.
# First read the HTTP response header which ends with a double CRLF.
# Calling ChannelReceiveUntilMatch will receive until match string is seen,
# or until a timeout occurs (IdleTimeoutMs property).  ChannelReceiveUntilMatch
# may read beyond the match string, but it will stop reading as soon as the match
# string is seen.
set caseSensitive 0
set matchStr "\r\n\r\n"
set success [CkSsh_ChannelReceiveUntilMatch $ssh $channelNum $matchStr "ansi" $caseSensitive]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Extract the HTTP header from the receive buffer.
# (GetReceiveTextS extracts up to and including the match string from the receive buffer)

set responseHeader [CkSsh_getReceivedTextS $ssh $channelNum $matchStr "ansi"]
puts "---- HTTP Response Header ----"
puts "$responseHeader"

# Now get the body of the HTTP response (this is the HTML content
# of http://www.chilkatsoft.com/xyz.html
# It's possible we've already received the entire HTTP response in the
# call to ChannelReceiveUntilMatch.  Therefore, we'll poll for any remaining data
# and wait a max of .2 seconds.

set pollTimeoutMs 200
set numBytesRead [CkSsh_ChannelPoll $ssh $channelNum $pollTimeoutMs]
# We're not checking for an error here.
# A return value of -2 means that no data was available and the poll simply timed out (not an error)
# A return value of -1 indicates an error.
# A return value greater than 0 indicates that additional data was received.

puts "---- HTML BODY ----"

# Extract the remainder of the accumulated data in the internal receive buffer.
# This should be our HTML body:

set htmlBody [CkSsh_getReceivedText $ssh $channelNum "ansi"]
puts "$htmlBody"

# Close the channel:
set success [CkSsh_ChannelSendClose $ssh $channelNum]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh]
    delete_CkSsh $ssh
    exit
}

# Disconnect
CkSsh_Disconnect $ssh

delete_CkSsh $ssh