sk-nat/NATRouter.cpp

/*
 * NATItem.cpp
 *
 *  Created on: 11-01-2017
 *      Author: Piotr Dergun
 */

#include "NATRouter.h"

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

NATRouter::NATRouter()
{
	this->initalizeNatTable();
}

NATRouter::NATRouter(string hostname) : Node(hostname)
{
	this->initalizeNatTable();
}

NATRouter::NATRouter(string hostname, string ip, string mask) : Node(hostname, ip, mask)
{
	this->initalizeNatTable();
}

NATRouter::NATRouter(string hostname, string ip, string mask, string gatewayIp) : Node(hostname, ip, mask, gatewayIp)
{
	this->initalizeNatTable();
}

int NATRouter::getFreePort()
{
	if (this->lastUsedPort == NAT_TABLE_LEN-1)
		this->lastUsedPort = 0;

	//if (this->natTable[this->lastUsedPort+1].isFree())
	//	return ++this->lastUsedPort;
	for (int i = this->lastUsedPort+1; i<NAT_TABLE_LEN; ++i)
			if (this->natTable[i].isFree())
			{
				this->lastUsedPort = i;
				return i;
			}

	for (int i = 1; i<this->lastUsedPort; ++i)
		if (this->natTable[i].isFree())
		{
			this->lastUsedPort = i;
			return i;
		}
/*
	for (int i=1; i<NAT_TABLE_LEN; ++i)
		if (this->natTable[i].isFree())
			return i;
*/
	return -1;	// nie ma żadnego wolnego portu
}

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

void NATRouter::onRecv()
{
	while (true)
	{
		Packet p = this->recv();
		stringstream s;

		if (p.getSrcPort() != 0)
		{
			// jezeli pakiet idzie z jednego wezla do drugiego w danej possieci to odeslij mu "jak switch"
			if (this->calculateNetwork(p.getDstIp(), this->getMask()) == this->getNetwork() && p.getDstIp() != this->getIp())
			{
				this->send(p, true);
			}
			else 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
			}
			this->delay();
		}
		else
		{
#ifndef DEBUG

			this->print("onRecv() sleeping...");
#endif
		}
		this->delay();

	}
}

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

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

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

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

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

/*
 * funkcja SNAT zapisuje w tablicy NAT
 * numer portu zrodlowego komputera z LAN
 * oraz jego IP i przeksztalca pakiet, zmieniajac
 * zrodlowy IP na IP zewn. routera oraz wolny
 * port z tablicy NAT. Jezeli portu nie ma to funkcja
 * czeka, az sie zwolni
 */
void NATRouter::sNAT(Packet *packet)
{
	int port;
	NATItem *natItem;
	bool allocated = false;
	stringstream ss;

	// mozliwe, ze juz port zostal zaalokowany, to trzeba wykorzystac
	port = this->getAllocatedPort(packet->getSrcIp(), packet->getSrcPort());
	if (port == -1)
		while ((port = this->getFreePort()) == -1)
		{
			//TESTOWO
			this->print("NAT table full, waiting 1s", true);
			this->delay(1);
		}
	else
		allocated = true;

	// wstawiam do tablicy NAT info ze port zarezerowany na odbior
	natItem = &this->natTable[port];
	natItem->setIp(packet->getSrcIp());
	natItem->setPort(packet->getSrcPort());

	if (allocated)
		natItem->increaseTimeout(15);
	else
		natItem->setTimeout(15);

	ss << packet->getSrcIp() << ":" << packet->getSrcPort();

	if (!allocated)
		this->natHelper.insert(pair<string, int>(ss.str(), port));

	ss.str("");
	ss << "SNAT " << packet->getSrcIp() << ":" << packet->getSrcPort() << " --> " << this->getWanIp() << ":" << port;

	packet->setSrcIp(this->getWanIp());	// zamieniam IP lokalne na WAN'owe
	packet->setSrcPort(port);			// zamieniam port lokalny na WAN'owy - z tablicy NAT

	this->print(ss.str(), true);
	this->delay();
	this->send(*packet, true);			// wysylam dalej
	natItem = NULL;
}

/*
 * funkcja DNAT ma za zadanie znalezc w tablicy NAT
 * port i adres IP wezla na ktory ma wrocic odpowiedz
 * z sieci Internet (z zewnatrz), a takze przedluzyc
 * czas zycia tego portu
 */
void NATRouter::dNAT(Packet* packet)
{
	NATItem *natItem = &this->natTable[packet->getDstPort()];

	stringstream ss;
	ss << "DNAT " << packet->getDstIp() << ":" << packet->getDstPort() << " --> " << natItem->getIp() << ":" << natItem->getPort();

	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
	natItem->increaseTimeout(5);			// podbijam o kolejne 5 sekund skoro transmisja trwa

	this->print(ss.str());
	this->delay();
	this->send(*packet, true);				// wysylam dalej

	natItem = NULL;
}

void NATRouter::setWanNetwork()
{
	this->netWanConf.network = this->calculateNetwork(this->getWanIp(), this->getWanMask());
}

string NATRouter::getWanNetwork()
{
	return this->netWanConf.network;
}

/*
 * funkcja szuka aktywnego zaalokowanego portu (aktywna
 * transmisja) w tablicy NAT dla pary (srcIp:srcPort)
 */
int NATRouter::getAllocatedPort(string srcIp, int srcPort)
{
	map<string, int>::iterator it;
	int pos = -1;
	/*for (int i=1; i<NAT_TABLE_LEN; ++i)
		if (this->natTable[i].getIp() == srcIp && this->natTable[i].getPort() == srcPort)
			return i;
*/
	stringstream ss;
	ss << srcIp << ":" << srcPort;

	it = this->natHelper.find(ss.str());
	if (it != this->natHelper.end())
	{
		// sprawdz czy wpis o podanym IP z nat nie zostal napisany (referencja nieaktualna)
		if (this->natTable[it->second].getIp() != srcIp || this->natTable[it->second].getPort() != srcPort)
			this->natHelper.erase(it);
		else
			pos = it->second;
	}

	return pos;
}

void NATRouter::freePorts()
{
	stringstream ss;
	int i, ports, peak=NAT_TABLE_LEN-1;

	Log portsLog;
	string name = "NAT";
	portsLog.setLogParams(3, GREEN, "\t\t");
	portsLog.setObjectName(&name);
	portsLog.setDelay(100000);

	while(true)
	{
		ports = 0;
		ss.str("");

		for (i=1; i<NAT_TABLE_LEN; ++i)
			if (this->natTable[i].isFree())
				++ports;

		if (ports < peak)
			peak = ports;

		ss << "Free/Reserved:\t" << ports << " (" << peak << ")/" << (NAT_TABLE_LEN-ports-1) << " (" << (NAT_TABLE_LEN-peak-1) << ")"; // poprawka na nieuzywany port 0

		portsLog.print(ss.str());
		portsLog.printProgressBar(4, 4, "Utilization", (float)(NAT_TABLE_LEN-ports-1)/(NAT_TABLE_LEN-1));
		portsLog.delay();
	}

}

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