(Perl) SSH Tunnel Inside another SSH Tunnel

Demonstrates how to create a TCP/IP socket connection through an SSH tunnel that is dynamic port forwarded through another SSH tunnel.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

# This example requires Chilkat version 9.5.0.50 or greater.
$tunnel = chilkat::CkSshTunnel->new();

$sshHostname = "www.ssh-serverA.com";
$sshPort = 22;

# Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->Connect($sshHostname,$sshPort);
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# Authenticate with the SSH server via a login/password
# or with a public key.  
# This example demonstrates SSH password authentication.
$success = $tunnel->AuthenticatePw("mySshLogin","mySshPassword");
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
# with dynamic port forwarding:
$tunnel->put_DynamicPortForwarding(1);

# We may optionally require that connecting clients authenticate with our SOCKS proxy server.
# To do this, set an inbound username/password.  Any connecting clients would be required to 
# use SOCKS5 with the correct username/password.
# If no inbound username/password is set, then our SOCKS proxy server will accept both
# SOCKS4 and SOCKS5 unauthenticated connections.

$tunnel->put_InboundSocksUsername("chilkat123");
$tunnel->put_InboundSocksPassword("password123");

# Start the listen/accept thread to begin accepting SOCKS proxy client connections.
# Listen on port 1080.
$success = $tunnel->BeginAccepting(1080);
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# Now that a background thread is running a SOCKS proxy server that forwards connections
# through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
# such as HTTP, POP3, SMTP, IMAP, FTP, Socket, etc.  The protocol may use SSL/TLS because the SSL/TLS
# will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
# connections may be routed through the SSH tunnel.

$tunnelB = chilkat::CkSocket->new();

# Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
$tunnelB->put_SocksHostname("localhost");
$tunnelB->put_SocksPort(1080);
$tunnelB->put_SocksVersion(5);
$tunnelB->put_SocksUsername("chilkat123");
$tunnelB->put_SocksPassword("password123");

# Open a new SSH tunnel through the existing tunnel (via what we treat as a SOCKS5 proxy,
# but it is actually a dynamic port-forwarded SSH tunnel).
$success = $tunnelB->SshOpenTunnel("www.ssh-serverB.com",22);
if ($success != 1) {
    print $tunnelB->lastErrorText() . "\r\n";
    exit;
}

# Authenticate with ssh-serverB.com
$success = $tunnelB->SshAuthenticatePw("uname","pwd");
if ($success != 1) {
    print $tunnelB->lastErrorText() . "\r\n";
    exit;
}

# OK, the SSH tunnel (within a tunnel) is setup.  Now open a channel within the tunnel.
# Once the channel is obtained, the Socket API may
# be used exactly the same as usual, except all communications
# are sent through the channel in the SSH tunnel.
# Any number of channels may be created from the same SSH tunnel.
# Multiple channels may coexist at the same time.

# Connect to an NIST time server and read the current date/time

$maxWaitMs = 4000;
$useTls = 0;
# channel is a Socket
$channel = $tunnelB->SshOpenChannel("time-c.nist.gov",37,$useTls,$maxWaitMs);
if ($tunnelB->get_LastMethodSuccess() == 0) {
    print $tunnelB->lastErrorText() . "\r\n";
    exit;
}

# The time server will send a big-endian 32-bit integer representing
# the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
# The ReceiveInt32 method will receive a 4-byte integer, but returns
# 1 or 0 to indicate success.  If successful, the integer
# is obtained via the ReceivedInt property.
$bigEndian = 1;
$success = $channel->ReceiveInt32($bigEndian);
if ($success != 1) {
    print $channel->lastErrorText() . "\r\n";

    exit;
}

$dt = chilkat::CkDateTime->new();
$dt->SetFromNtpTime($channel->get_ReceivedInt());

# Show the current local date/time
$bLocalTime = 1;
print "Current local date/time: " . $dt->getAsRfc822($bLocalTime) . "\r\n";

# Close the SSH channel.
$success = $channel->Close($maxWaitMs);
if ($success != 1) {
    print $channel->lastErrorText() . "\r\n";

    exit;
}

# Stop the background listen/accept thread:
$waitForThreadExit = 1;
$success = $tunnel->StopAccepting($waitForThreadExit);
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

# Close the SSH tunnel (would also kick any remaining connected clients).
$success = $tunnel->CloseTunnel($waitForThreadExit);
if ($success != 1) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}