(Objective-C) SSH Tunnel (Port Forwarding via direct-tcpip channel)

Demonstrates how to create an SSH tunnel to a remote hostname:port via a direct-tcpip channel.

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

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

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

// Connect to an SSH server:
NSString *hostname = 0;
int port;

// Hostname may be an IP address or hostname:
hostname = @"192.168.1.117";
port = 22;

BOOL success = [ssh Connect: hostname port: [NSNumber numberWithInt: port]];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Wait a max of 5 seconds when reading responses..
ssh.IdleTimeoutMs = [NSNumber numberWithInt:5000];

// Authenticate using login/password:
success = [ssh AuthenticatePw: @"chilkat" password: @"myPassword"];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Open a direct-tcpip channel.  We want the SSH server to connect
// to www.chilkatsoft.com, port 80 (i.e. the web server).
// Data sent through the SSH tunnel is forwarded to the remote
// host:port.  (Note: The remote host:port does not need to be 
// a web server.  It can be anything.  It can be your own
// customer application server that listens on a port, or any
// other type of server.)
// When we read from the SSH channel, we'll be reading data
// sent from the remote host:port (i.e. the web server in this
// example).
int channelNum;
channelNum = [[ssh OpenDirectTcpIpChannel: @"www.chilkatsoft.com" port: [NSNumber numberWithInt: 80]] intValue];
if (channelNum < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Build a simple HTTP GET request for http://www.chilkatsoft.com/xyz.html
NSString *httpReq = @"GET /xyz123.html HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n";

// Send the HTTP request:
success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: httpReq charset: @"ansi"];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Get the HTTP response.
// First read the HTTP response header which ends with a double CRLF.
// Calling ChannelReceiveUntilMatch will receive until match string is seen,
// or until a timeout occurs (IdleTimeoutMs property).  ChannelReceiveUntilMatch
// may read beyond the match string, but it will stop reading as soon as the match
// string is seen.
BOOL caseSensitive = NO;
NSString *matchStr = @"\r\n\r\n";
success = [ssh ChannelReceiveUntilMatch: [NSNumber numberWithInt: channelNum] matchPattern: matchStr charset: @"ansi" caseSensitive: caseSensitive];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Extract the HTTP header from the receive buffer.
// (GetReceiveTextS extracts up to and including the match string from the receive buffer)
NSString *responseHeader = 0;
responseHeader = [ssh GetReceivedTextS: [NSNumber numberWithInt: channelNum] substr: matchStr charset: @"ansi"];
NSLog(@"%@",@"---- HTTP Response Header ----");
NSLog(@"%@",responseHeader);

// Now get the body of the HTTP response (this is the HTML content
// of http://www.chilkatsoft.com/xyz.html
// It's possible we've already received the entire HTTP response in the
// call to ChannelReceiveUntilMatch.  Therefore, we'll poll for any remaining data
// and wait a max of .2 seconds.
int numBytesRead;
int pollTimeoutMs = 200;
numBytesRead = [[ssh ChannelPoll: [NSNumber numberWithInt: channelNum] pollTimeoutMs: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
// We're not checking for an error here.
// A return value of -2 means that no data was available and the poll simply timed out (not an error)
// A return value of -1 indicates an error.
// A return value greater than 0 indicates that additional data was received.

NSLog(@"%@",@"---- HTML BODY ----");

// Extract the remainder of the accumulated data in the internal receive buffer.
// This should be our HTML body:
NSString *htmlBody = 0;
htmlBody = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"ansi"];
NSLog(@"%@",htmlBody);

// Close the channel:
success = [ssh ChannelSendClose: [NSNumber numberWithInt: channelNum]];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Disconnect
[ssh Disconnect];