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Re: Adding network proxy support to U++ [message #43853 is a reply to message #43789]

Sun, 09 November 2014 16:56

Oblivion
Messages: 1214
Registered: August 2007

Senior Contributor

Hello Mindtraveller, Mirek.
Thank you for your suggestions. And I apologize I couldn't reply earlier, I was away for a while.

Here is what happened meanwhile:

After some toying with the network proxy idea for U++, I concluded that writing a monolithic, all-in-one network proxy class wouldn't be very effective (also imho, it would not be so upp-ish) way to implement it.

So I ditched the somewhat bloated, monolithic NetProxy class in favour of a modular approach, and abstracted a common interface and code for sync/async network proxies. This abstract class I called NetworkProxy. It contains all the necessary elements so far to succesfully implement most popular types of network proxy protocols. It has some advantages: Permits adding new/other sync/async network proxy protocols easily, relatively faster than NetProxy (due to less control code). Also we now have polymorphism: With this approach we can use a single Array object to contain a collection of different types of proxy instances if needed.

NetworkProxy abstract class currently has three derivatives with almost-identical interface: HttpProxy, Socks4Proxy, Socks5Proxy.

Here is the current "public" interface of NetworkProxy class and its derivatives (Note that SSL support and binding methods (in SOCKS4/5 proxies) are not yet implemented):

class NetworkProxy
{
  
public:
    enum ProxyType      { HTTP = 1, SOCKS4, SOCKS5 };
        
    NetworkProxy&       Attach(TcpSocket& sock)                         
    NetworkProxy&       Host(const String& host)    
    NetworkProxy&       Port(int port)                              
    NetworkProxy&       Timeout(int ms)                             

    TcpSocket*          GetSocket() const                           
    int                 GetType() const                               

    bool                Connect(const String& host, int port);
    void                StartConnect(const String& host, int port);
    virtual bool        Do() = 0;

    bool                InProgress() const                        
    bool                IsSuccess() const                      
    bool                IsFailure() const                           

    String              GetErrorDesc() const                     

    NetworkProxy();
    virtual ~NetworkProxy();    
};

class HttpProxy : public NetworkProxy
{
  
public:
    HttpProxy&          Auth(const String& user, const String& pass) 
    bool                Do();
    
    HttpProxy();
    HttpProxy(TcpSocket& sock, const String& host, int port, const String& user = Null, const String& pass = Null);
    ~HttpProxy();
};

class Socks4Proxy : public NetworkProxy
{
   
public:
    Socks4Proxy&        Auth(const String& user)                
    bool                Do();
    
    Socks4Proxy();
    Socks4Proxy(TcpSocket& sock, const String& host, int port, const String& user = Null);
    ~Socks4Proxy();
};


class Socks5Proxy : public NetworkProxy
{
 
public:
    Socks5Proxy&        Auth(const String& user, const String& pass)     
    bool                Do();
    
    Socks5Proxy();
    Socks5Proxy(TcpSocket& sock, const String& host, int port, const String& user = Null, const String& pass = Null);
    ~Socks5Proxy();
};

As Mindtraveller suggested, I corrected the interface, but any further corrections, suggestions or ideas are always welcome.

To give you further idea, here is the actual and complete working example code of async HTTP_CONNECT proxy (It simply connects to five different Ftp servers via a public http proxy and gets the server greeting):

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

using namespace Upp;

CONSOLE_APP_MAIN
{
	
	static const char *target_hosts[] = {
		"ftp.uni-erlangen.de",	// Aminet ftp server.
		"ftp.mozilla.org",	// Mozilla ftp server.
		"ftp.freebsd.org",	// FreeBSD ftp server.
		"ftp.microsoft.com",	// Microsoft ftp server.
		"ftp.kde.org",		// KDE ftp server.
	};
	
	Array<TcpSocket> sockets;
	Array<HttpProxy> proxies;
	SocketWaitEvent socketevent;

	for(int i = 0; i < 5; i++) {
		TcpSocket& socket = sockets.Add();
		socketevent.Add(socket);
		HttpProxy& proxy = proxies.Add();
		proxy.Attach(socket);
		proxy.Host("97.77.104.22");
		proxy.Port(80);
		proxy.StartConnect(target_hosts[i], 21);
	}
		
	while(proxies.GetCount()) {
		socketevent.Wait(10);
		for(int i = 0; i < proxies.GetCount(); i++) {
			HttpProxy& proxy = proxies[i];
			proxy.Do();
			if(!proxy.InProgress()) {
				if(proxy.IsFailure())
					Cout() << "Proxy connection failed. Reason: " << proxy.GetErrorDesc() << "\r\n";
				else
				if(proxy.IsSuccess()) {
					TcpSocket *socket = proxy.GetSocket();
					Cout() << "Succesfully connected via: " << socket->GetPeerAddr() << "\r\n";
					Cout() << socket->GetLine() << "\r\n";
				}
				proxies.Remove(i);
				break;
			}
		}
	}
	
	for(int i = 0; i < sockets.GetCount(); i++)
		sockets[i].Close();
}

There are some small quirks to iron out, but I am planning to upload the complete package next weekend.

Regards,
Oblivion.

Github page: https://github.com/ismail-yilmaz
Bobcat the terminal emulator: https://github.com/ismail-yilmaz/Bobcat

[Updated on: Sun, 09 November 2014 17:14]

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