Objective-C

Request SSH X11 Forwarding

Demonstrates the Chilkat Ssh.SendReqX11Forwarding method, which sends an X11-forwarding request on a session channel. The arguments are the channel number, whether forwarding is limited to a single connection, and the X11 authentication protocol, cookie, and screen number.

Background: X11 forwarding lets a graphical program running on the remote host display its window on your local machine, tunneled over SSH. This is a low-level method that only sends the protocol request — your application is still responsible for the local X server side of the arrangement. The authentication cookie guards the forwarded display, so it should be a freshly generated value rather than a fixed constant.

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Objective-C

#import <CkoSsh.h>
#import <NSString.h>

BOOL success = NO;

//  Demonstrates the Ssh.SendReqX11Forwarding method, which sends an SSH X11-forwarding request
//  on a session channel.  The 1st argument is the channel number, the 2nd limits forwarding to a
//  single connection, and the 3rd through 5th supply the X11 authentication protocol, cookie,
//  and screen number.

CkoSsh *ssh = [[CkoSsh alloc] init];

int sshPort = 22;
success = [ssh Connect: @"ssh.example.com" port: [NSNumber numberWithInt: sshPort]];
if (success == NO) {
    NSLog(@"%@",ssh.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 = [ssh AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  Open a session channel.  A negative return value indicates failure.
int channelNum = [[ssh OpenSessionChannel] intValue];
if (channelNum < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  Request X11 forwarding.  Named variables make each argument's meaning clear.
BOOL singleConnection = NO;
NSString *authProt = @"MIT-MAGIC-COOKIE-1";
NSString *authCookie = @"d92f5e1a7c8b4306af17c2e5b9d43081";
int screenNum = 0;
success = [ssh SendReqX11Forwarding: [NSNumber numberWithInt: channelNum] singleConnection: singleConnection authProt: authProt authCookie: authCookie screenNum: [NSNumber numberWithInt: screenNum]];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@",@"X11 forwarding requested.");

[ssh Disconnect];