sk-nat/NATRouter.cpp

/*
 * NATItem.cpp
 *
 *  Created on: 10-01-2017
 *      Author: Piotr Dergun
 */

#include "NATRouter.h"

NATRouter::NATRouter()
{
	try
	{
		natTable = new NATItem[65536];
	}
	catch(bad_alloc &ba)
	{
		cerr << "Nie mozna zaalokowac pamieci dla tablicy NAT!" << endl;
		exit(1);
	}
}

int NATRouter::getFreePort()
{
	for (int i=0; i<65536; ++i)
		if (this->natTable[i].isFree())
			return i;

	return -1;	// nie ma żadnego wolnego portu
}

NATRouter::~NATRouter()
{
	if (natTable)
		delete [] natTable;
}

void NATRouter::onRecv()
{
	Packet p = this->recv();

	if (p.getSrcPort() != 0)
	{
		if (p.getDstIp() != this->getIp() && p.getDstIp() != this->getWanIp())
		{
			this->sNAT(&p);
		}
		else if (p.getDstIp() == this->getWanIp() && !this->natTable[p.getDstPort()].isFree())
		{
			this->dNAT(&p);
		}
		else
		{
			// TUTAJ ew. implementacja obslugi pakietu adresowanego do routera
		}
	}
}

void NATRouter::setWanIp(string wanIp)
{
	this->netWanConf.ip = wanIp;
}

void NATRouter::setWanMask(string wanMask)
{
	this->netWanConf.mask = wanMask;
}

void NATRouter::setWanGatewayIp(string wanGatewayIp)
{
	this->netWanConf.gatewayIp = wanGatewayIp;
}

string NATRouter::getWanIp()
{
	return this->netWanConf.ip;
}

string NATRouter::getWanMask()
{
	return this->netWanConf.mask;
}

void NATRouter::sNAT(Packet *packet)
{
	int port;
	NATItem *natItem;

	while ((port = this->getFreePort()) == -1)
	{
		//TESTOWO
		cout << "Brak wolnych portow, czekam 1s" << endl;
		sleep(1);
	}

	// wstawiam do tablicy NAT info ze port zarezerowany na odbior
	natItem = &this->natTable[port];
	natItem->setIp(packet->getSrcIp());
	natItem->setPort(packet->getSrcPort());
	packet->setSrcIp(this->getWanIp());	// zamieniam IP lokalne na WAN'owe
	packet->setSrcPort(port);			// zamieniam port lokalny na WAN'owy - z tablicy NAT

	this->send(*packet, true);			// wysylam dalej

	natItem = NULL;
}

void NATRouter::dNAT(Packet* packet)
{
	NATItem *natItem = &this->natTable[packet->getDstPort()];

	packet->setDstIp(natItem->getIp());		// zamieniam IP lokalne na WAN'owe
	packet->setDstPort(natItem->getPort());	// zamieniam port NAT na lokalny wezla
	natItem->free();						// zwalniam port w routerze

	this->send(*packet, true);				// wysylam dalej

	natItem = NULL;
}

string NATRouter::getWanGatewayIp()
{
	return this->netWanConf.gatewayIp;
}