Zig Requires Chilkat v11.0.0+

SSH Tunnel Inside another SSH Tunnel

See more SSH Tunnel Examples

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

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const tunnel = try chilkat.SshTunnel.init();
    defer tunnel.deinit();

    const ssh_hostname = "www.ssh-serverA.com";
    const ssh_port = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    tunnel.connect(ssh_hostname, ssh_port) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    tunnel.authenticatePw("mySshLogin", "mySshPassword") catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
    // with dynamic port forwarding:
    tunnel.setDynamicPortForwarding(true);

    // 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.setInboundSocksUsername("chilkat123");
    tunnel.setInboundSocksPassword("password123");

    // Start the listen/accept thread to begin accepting SOCKS proxy client connections.
    // Listen on port 1080.
    tunnel.beginAccepting(1080) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // 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.

    const tunnel_b = try chilkat.Socket.init();
    defer tunnel_b.deinit();

    // Indicate that the socket object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
    tunnel_b.setSocksHostname("localhost");
    tunnel_b.setSocksPort(1080);
    tunnel_b.setSocksVersion(5);
    tunnel_b.setSocksUsername("chilkat123");
    tunnel_b.setSocksPassword("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).
    tunnel_b.sshOpenTunnel("www.ssh-serverB.com", 22) catch {
        std.debug.print("{s}\n", .{try tunnel_b.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with ssh-serverB.com
    tunnel_b.sshAuthenticatePw("uname", "pwd") catch {
        std.debug.print("{s}\n", .{try tunnel_b.getLastErrorText(alloc)});
        return;
    };

    // 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
    const channel = try chilkat.Socket.init();
    defer channel.deinit();
    const max_wait_ms = 4000;
    const use_tls = false;
    tunnel_b.sshNewChannel("time-c.nist.gov", 37, use_tls, max_wait_ms, channel) catch {
        std.debug.print("{s}\n", .{try tunnel_b.getLastErrorText(alloc)});
        return;
    };

    // 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
    // true or false to indicate success.  If successful, the integer
    // is obtained via the ReceivedInt property.
    const big_endian = true;
    channel.receiveInt32(big_endian) catch {
        std.debug.print("{s}\n", .{try channel.getLastErrorText(alloc)});
        return;
    };

    const dt = try chilkat.DateTime.init();
    defer dt.deinit();
    dt.setFromNtpTime(channel.getReceivedInt()) catch {};

    // Show the current local date/time
    const b_local_time = true;
    std.debug.print("Current local date/time: {s}\n", .{try dt.getAsRfc822(alloc, b_local_time)});

    // Close the SSH channel.
    channel.close(max_wait_ms) catch {
        std.debug.print("{s}\n", .{try channel.getLastErrorText(alloc)});
        return;
    };

    // Stop the background listen/accept thread:
    const wait_for_thread_exit = true;
    tunnel.stopAccepting(wait_for_thread_exit) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Close the SSH tunnel (would also kick any remaining connected clients).
    tunnel.closeTunnel(wait_for_thread_exit) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };
}