Objective-C

SSH Tunnel Uncommon Options

Demonstrates the UncommonOptions property, which enables optional behavior for uncommon requirements. The default is an empty string; provide a comma-separated list of keywords to enable more than one option. Available keywords are listed in the reference documentation.

Background: This is a catch-all for narrow workarounds that do not warrant their own properties — forcing a specific signature algorithm, disabling the periodic keep-alive, removing weak MACs, bypassing a VPN on Android, and so on. Most applications never set it. When you do, it is usually to satisfy a particular server's quirk or a specific security requirement, and the exact keyword matters, so consult the documented list rather than guessing.

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Objective-C

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

BOOL success = NO;

//  Demonstrates the SshTunnel.UncommonOptions property, which enables optional behavior for
//  uncommon requirements.  The default is an empty string, appropriate for most applications.
//  Provide a comma-separated list of keywords to enable more than one option.

CkoSshTunnel *tunnel = [[CkoSshTunnel alloc] init];

//  For example, disable the periodic keep-alive ignore message and remove weak MAC algorithms
//  from those offered.  Available keywords are listed in the reference documentation.
tunnel.UncommonOptions = @"NoKeepAliveIgnoreMsg,no-weak-mac-algs";

tunnel.DestHostname = @"db.internal.example.com";
tunnel.DestPort = [NSNumber numberWithInt:5432];

int sshPort = 22;
success = [tunnel Connect: @"ssh.example.com" port: [NSNumber numberWithInt: sshPort]];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    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.
NSString *password = @"mySshPassword";

success = [tunnel AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

int listenPort = 1080;
success = [tunnel BeginAccepting: [NSNumber numberWithInt: listenPort]];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

NSLog(@"%@",@"Tunnel established.");

BOOL waitForThreadExit = YES;
success = [tunnel CloseTunnel: waitForThreadExit];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}