(Objective-C) SSH Tunnel with Dynamic Port Forwarding

Demonstrates how to start a background thread that runs a portable SSH tunnel w/ dynamic port forwarding that the foreground thread can use for establishing connections through an SSH tunnel.

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#import <CkoGlobal.h>
#import <CkoSshTunnel.h>
#import <NSString.h>
#import <CkoHttp.h>

// Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
CkoGlobal *chilkatGlob = [[CkoGlobal alloc] init];
BOOL success = [chilkatGlob UnlockBundle: @"Anything for 30-day trial."];
if (success != YES) {
    NSLog(@"%@",chilkatGlob.LastErrorText);
    return;
}

// This example requires Chilkat version 9.5.0.50 or greater.
CkoSshTunnel *tunnel = [[CkoSshTunnel alloc] init];

NSString *sshHostname = @"sftp.example.com";
int sshPort = 22;

// Connect to an SSH server and establish the SSH tunnel:
success = [tunnel Connect: sshHostname port: [NSNumber numberWithInt: sshPort]];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Authenticate with the SSH server via a login/password
// or with a public key.  
// This example demonstrates SSH password authentication.
success = [tunnel AuthenticatePw: @"mySshLogin" password: @"mySshPassword"];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
// with dynamic port forwarding:
tunnel.DynamicPortForwarding = YES;

// 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.InboundSocksUsername = @"chilkat123";
tunnel.InboundSocksPassword = @"password123";

// Start the listen/accept thread to begin accepting SOCKS proxy client connections.
// Listen on port 1080.
success = [tunnel BeginAccepting: [NSNumber numberWithInt: 1080]];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    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, 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.

// For this example, let's do a simple HTTPS request:
NSString *url = @"https://www.ethereum.org/";

CkoHttp *http = [[CkoHttp alloc] init];

// Indicate that the HTTP object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
http.SocksHostname = @"localhost";
http.SocksPort = [NSNumber numberWithInt:1080];
http.SocksVersion = [NSNumber numberWithInt:5];
http.SocksUsername = @"chilkat123";
http.SocksPassword = @"password123";

http.SendCookies = YES;
http.SaveCookies = YES;
http.CookieDir = @"memory";

// Do the HTTPS page fetch (through the SSH tunnel)
NSString *html = [http QuickGetStr: url];
if (http.LastMethodSuccess != YES) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

// Stop the background listen/accept thread:
BOOL waitForThreadExit = YES;
success = [tunnel StopAccepting: waitForThreadExit];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

// Close the SSH tunnel (would also kick any remaining connected clients).
success = [tunnel CloseTunnel: waitForThreadExit];
if (success != YES) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}