NetProxy package for Ultimate++
--------------------------------

This delegate class, formerly known as NetworkProxy, encapsulates two widely used network 
proxy protocols: Http tunneling and SOCKS.

Features and Highlights
-----------------------

- Uses HTTP_CONNECT method for http tunneling.
- Encapsulates SOCKS proxy protocol version 4/4a, and version 5, as defined in RFC 1928 and RFC 1929. 
- In SOCKS mode, NetProxy can work with both IPv4 and IPv6 address families.
- In SOCKS mode, NetProxy allows BIND requests.
- In SOCKS mode, NetProxy allows remote name lookups (DNS).
- Supports both synchronous and asynchronous operation modes.
- Allows SSL connections to the target machine (not to proxy itself) in both Http and SOCKS modes.
- Package comes with full public API document for Topic++, and has a typical BSD license.

Known Issues
-----------------------

- In SOCKS mode, NetProxy currently does not allow UDP association.

History
-----------------------

- 2017-09-23: Initial release of version 2.0:
              A change in naming: NetworkProxy is from now on called NetProxy.
              This change is in parallel with the change in class design.
              There is now a single class that can make both HTTP_CONNECT and SOCKS requests.
              Handling of socks BIND requests is simplified.
              Internal cleanup redesigne allowed some performance gain around %4.
              

class NetworkFoo {

public:
    Gate<TcpSocket&>   WhenProxy; // Or WhenConnect
};


//...

NetworkFoo nwf;

nwf.WhenProxy = [=, proxy_host, proxy_port, target_host, target_port](TcpSocket& sock) {
                   
                   NetProxy proxy(sock, proxy_host, proxy_port);
                   proxy.Timeout(10000)
                        .Auth("user", "password")
                        .Socks5();
                   return proxy.Connect(target_host, target_port);
              };

SocksProxyExample     - Demonstrates a simple SOCKS5 connection, using NetProxy package.
SocksProxyExampleNB   - Demonstrates a simple, non-blocking SOCKS5 connection, using NetProxy package.

#include <Core/Core.h>
#include <NetProxy/NetProxy.h>

using namespace Upp;

// This example demonstrates the basic usage of NetProxy class with socks5 tunnels.
// Default proxy server: Turk Telekom, a well-known ISP in Turkey. No auth required...
// Target server: test.rebex.net -> A well-known FTP/SFTP test server.

CONSOLE_APP_MAIN
{
	StdLogSetup(LOG_COUT|LOG_FILE);
	NetProxy::Trace();
	
	const char *proxy_server = "88.249.26.113";
	const int   proxy_port   = 1080;

	TcpSocket sock;

	NetProxy socksproxy(sock, proxy_server, proxy_port);
	if(socksproxy.Timeout(10000).Socks5().Connect("test.rebex.net", 21)) {
		RLOG("-------------");
		RLOG(sock.GetLine());	// Get the first line of FTP server HELO...
		RLOG("-------------");
		return;
	}
	RLOG(socksproxy.GetErrorDesc());
}

#include <Core/Core.h>
#include <Core/SSH/SSH.h>
#include <NetProxy/NetProxy.h>

using namespace Upp;

// This example demonstrates a basic SSH2 connection over a Socks5 proxy.

// WARNING: The sole purpose of this example is to demonstrate the  usage of
//          NetProxy package with the SSH package. The example uses an anon.
//          proxy server (with  no authentication) to access  a public  SFTP
//          server.
//
//	    NEVER  USE A PUBLIC PROXY SERVER FOR YOUR SSH CONNECTIONS. IN FACT,
//          IT IS HIGHLY RECOMMENDED TO COMPLETELY AVOID USING PROXY SERVERS FOR
//          SENSITIVE/ENCRYPTED DATA TRANSFERS.

CONSOLE_APP_MAIN
{
	StdLogSetup(LOG_COUT|LOG_FILE);
	Ssh::Trace();
	NetProxy::Trace();
	
	const char *proxy_server = "88.249.26.113";		// Anonymous socks proxy server of a well-known ISP in Turkey (Turk Telekom).
	const int   proxy_port   = 1080;
	
	const char *ssh_server   = "test.rebex.net";	// A well-known and popular SSH test server.
	const int   ssh_port     = 22;

	SshSession session;
	session.WhenProxy = [&]() -> bool
	{
		NetProxy socksproxy(session.GetSocket(), proxy_server, proxy_port);
		return socksproxy.Timeout(10000).Socks5().Connect(ssh_server, ssh_port);
	};
	
	if(session.Timeout(30000).Connect(ssh_server, ssh_port, "demo", "password")) {
		SFtp sftp(session);
		String s = sftp.LoadFile("./readme.txt");
		if(!sftp.IsError()) {
			RLOG("---------------------------");
			RLOG(s);
			RLOG("----------------------------");
		}
		return;
	}
	RLOG(session.GetErrorDesc());
}