Symulacja NAT na przedmiot Symulacje Komputerowe
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/*
* 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;
}