Connect to an SFTP Server Through a Jump Host

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Demonstrates the Chilkat SFtp.ConnectThroughSsh method, which connects to an SFTP server through an already connected and authenticated Ssh object. The first argument is the jump-host Ssh object, and the second and third are the destination hostname and port.

Background: This is the "jump host" (bastion) pattern: the application connects to a reachable gateway, then tunnels onward to an SFTP server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SFtp object — still requiring its own authentication and InitializeSftp — that happens to be routed through the first connection.

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#include <C_CkSsh.h>
#include <C_CkSFtp.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSsh sshJump;
    int port;
    const char *password;
    HCkSFtp sftp;

    success = FALSE;

    //  Demonstrates the SFtp.ConnectThroughSsh method, which connects to an SFTP server through an
    //  already connected and authenticated Ssh object (a jump host).  The 1st argument is the Ssh
    //  object, and the 2nd and 3rd are the destination hostname and port.

    sshJump = CkSsh_Create();

    //  Connect and authenticate to the jump host first.
    port = 22;
    success = CkSsh_Connect(sshJump,"jump.example.com",port);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(sshJump));
        CkSsh_Dispose(sshJump);
        return;
    }

    //  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 = "mySshPassword";

    success = CkSsh_AuthenticatePw(sshJump,"myJumpLogin",password);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(sshJump));
        CkSsh_Dispose(sshJump);
        return;
    }

    //  Connect to the SFTP server through the jump host.
    sftp = CkSFtp_Create();
    success = CkSFtp_ConnectThroughSsh(sftp,sshJump,"sftp.internal.example.com",port);
    if (success == FALSE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSsh_Dispose(sshJump);
        CkSFtp_Dispose(sftp);
        return;
    }

    //  Authenticate to the SFTP server (its own credentials), then initialize SFTP.
    success = CkSFtp_AuthenticatePw(sftp,"mySshLogin",password);
    if (success == FALSE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSsh_Dispose(sshJump);
        CkSFtp_Dispose(sftp);
        return;
    }

    success = CkSFtp_InitializeSftp(sftp);
    if (success == FALSE) {
        printf("%s\n",CkSFtp_lastErrorText(sftp));
        CkSsh_Dispose(sshJump);
        CkSFtp_Dispose(sftp);
        return;
    }

    printf("Connected to the SFTP server through the jump host.\n");

    CkSFtp_Disconnect(sftp);
    CkSsh_Disconnect(sshJump);


    CkSsh_Dispose(sshJump);
    CkSFtp_Dispose(sftp);

    }