PureBasic

SSH Tunnel Through an Outbound SOCKS Proxy

Demonstrates reaching the SSH server through an outbound SOCKS proxy using the SocksVersion, SocksHostname, SocksPort, SocksUsername, and SocksPassword properties.

Background: This is the reverse direction from dynamic forwarding: here a SOCKS proxy is used to reach the SSH server, for networks where outbound connections must pass through one. SocksVersion is the switch — 0 means no SOCKS, while 4 or 5 selects the protocol. SOCKS5 supports username/password authentication and remote DNS; SOCKS4 supports only a username.

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IncludeFile "CkSshTunnel.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Demonstrates reaching the SSH server through an outbound SOCKS proxy using the SshTunnel
    ;  properties SocksVersion, SocksHostname, SocksPort, SocksUsername, and SocksPassword.

    tunnel.i = CkSshTunnel::ckCreate()
    If tunnel.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Set SocksVersion to 4 or 5 to route the outbound connection to the SSH server through a SOCKS
    ;  proxy.  A value of 0 (the default) means no SOCKS proxy.
    CkSshTunnel::setCkSocksVersion(tunnel, 5)
    CkSshTunnel::setCkSocksHostname(tunnel, "socks.example.com")
    CkSshTunnel::setCkSocksPort(tunnel, 1080)

    ;  SOCKS4 supports only a username; SOCKS5 supports username and password.
    CkSshTunnel::setCkSocksUsername(tunnel, "myProxyLogin")
    CkSshTunnel::setCkSocksPassword(tunnel, "myProxyPassword")

    CkSshTunnel::setCkDestHostname(tunnel, "db.internal.example.com")
    CkSshTunnel::setCkDestPort(tunnel, 5432)

    ;  Connect to the SSH server through the SOCKS proxy configured above.
    sshPort.i = 22
    success = CkSshTunnel::ckConnect(tunnel,"ssh.example.com",sshPort)
    If success = 0
        Debug CkSshTunnel::ckLastErrorText(tunnel)
        CkSshTunnel::ckDispose(tunnel)
        ProcedureReturn
    EndIf

    ;  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.
    password.s = "mySshPassword"

    success = CkSshTunnel::ckAuthenticatePw(tunnel,"mySshLogin",password)
    If success = 0
        Debug CkSshTunnel::ckLastErrorText(tunnel)
        CkSshTunnel::ckDispose(tunnel)
        ProcedureReturn
    EndIf

    listenPort.i = 1080
    success = CkSshTunnel::ckBeginAccepting(tunnel,listenPort)
    If success = 0
        Debug CkSshTunnel::ckLastErrorText(tunnel)
        CkSshTunnel::ckDispose(tunnel)
        ProcedureReturn
    EndIf

    Debug "Tunnel established through the SOCKS proxy."

    waitForThreadExit.i = 1
    success = CkSshTunnel::ckCloseTunnel(tunnel,waitForThreadExit)
    If success = 0
        Debug CkSshTunnel::ckLastErrorText(tunnel)
        CkSshTunnel::ckDispose(tunnel)
        ProcedureReturn
    EndIf



    CkSshTunnel::ckDispose(tunnel)


    ProcedureReturn
EndProcedure