Objective-C

SSH Tunnel Per-Client Logging and Client Identifier

Demonstrates the ClientLogDir and ClientIdentifier properties. When ClientLogDir is set, a separate log file is created for each tunnel client; ClientIdentifier is the SSH client-identification string sent during the handshake.

Note: The log paths are relative to the application's current working directory. Absolute paths may also be used.

Background: When many clients share one tunnel, a single combined log is hard to follow, so ClientLogDir gives each connection its own file — the fastest way to diagnose one misbehaving client. ClientIdentifier sets the version string the server sees; overriding the default is occasionally needed for compatibility with servers that key behavior off the client identification, or simply to label your application in server logs.

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Objective-C

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

BOOL success = NO;

//  Demonstrates the SshTunnel per-client logging properties ClientLogDir and ClientIdentifier.

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

//  When ClientLogDir is set, a separate log file is created for each tunnel client in this
//  directory, which is useful for troubleshooting individual connections.
tunnel.ClientLogDir = @"qa_output/client_logs";

//  The SSH client-identification string sent to the SSH server during the handshake.
tunnel.ClientIdentifier = @"SSH-2.0-MyTunnelApp_1.0";

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 running; each client is logged in ",tunnel.ClientLogDir);

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