(C) SMTP over Multiple Hop SSH

Demonstrates how to send email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => SmtpServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

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#include <C_CkSsh.h>
#include <C_CkMailMan.h>
#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    HCkSsh ssh1;
    BOOL success;
    HCkSsh ssh2;
    HCkMailMan mailman;
    HCkEmail email;

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

    ssh1 = CkSsh_Create();

    // Connect directly to the 1st SSH server.
    success = CkSsh_Connect(ssh1,"serverssh1.com",22);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh1));
        CkSsh_Dispose(ssh1);
        return;
    }

    // Authenticate using login/password:
    success = CkSsh_AuthenticatePw(ssh1,"ssh1Login","ssh1Password");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh1));
        CkSsh_Dispose(ssh1);
        return;
    }

    // Connect through the 1st SSH connection to reach a 2nd SSH server.
    // Note: Any number of SSH connections may be simultaneously tunneled through a single
    // existing SSH connection.
    ssh2 = CkSsh_Create();
    success = CkSsh_ConnectThroughSsh(ssh2,ssh1,"serverssh2.com",22);
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh2));
        CkSsh_Dispose(ssh1);
        CkSsh_Dispose(ssh2);
        return;
    }

    // Authenticate with ssh2...
    success = CkSsh_AuthenticatePw(ssh2,"ssh2Login","ssh2Password");
    if (success != TRUE) {
        printf("%s\n",CkSsh_lastErrorText(ssh2));
        CkSsh_Dispose(ssh1);
        CkSsh_Dispose(ssh2);
        return;
    }

    mailman = CkMailMan_Create();

    // Tell the mailman object to connect to the SMTP server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => SMTPServer
    success = CkMailMan_UseSsh(mailman,ssh2);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkSsh_Dispose(ssh1);
        CkSsh_Dispose(ssh2);
        CkMailMan_Dispose(mailman);
        return;
    }

    // Set the SMTP server.
    CkMailMan_putSmtpHost(mailman,"smtp.someserver.com");

    // Set the SMTP login/password (if required)
    CkMailMan_putSmtpUsername(mailman,"myUsername");
    CkMailMan_putSmtpPassword(mailman,"myPassword");

    // Create a new email object
    email = CkEmail_Create();

    CkEmail_putSubject(email,"This is a test");
    CkEmail_putBody(email,"This is a test");
    CkEmail_putFrom(email,"Chilkat Support <support@chilkatsoft.com>");
    success = CkEmail_AddTo(email,"Chilkat Admin","admin@chilkatsoft.com");

    success = CkMailMan_SendEmail(mailman,email);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkSsh_Dispose(ssh1);
        CkSsh_Dispose(ssh2);
        CkMailMan_Dispose(mailman);
        CkEmail_Dispose(email);
        return;
    }

    // Close the connection with the server.  This closes the tunnel through ssh2.
    success = CkMailMan_CloseSmtpConnection(mailman);
    if (success != TRUE) {
        printf("Connection to SMTP server not closed cleanly.\n");
    }

    printf("Mail Sent!\n");

    // Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    // The connection with ssh1 is still alive, and may be used for more connections.
    CkSsh_Disconnect(ssh2);

    CkSsh_Disconnect(ssh1);


    CkSsh_Dispose(ssh1);
    CkSsh_Dispose(ssh2);
    CkMailMan_Dispose(mailman);
    CkEmail_Dispose(email);

    }