www.pudn.com > PIPMasq.zip > ping.cpp

#include "stdafx.h" 
#include "PIPMasq.h" 
 
////////////////////////// PingServer ///////////////////////////////// 
 
PingServer::PingServer(PseudIF* pseudIF) 
{ 
	m_pseudIF = pseudIF; 
} 
 
PingServer::~PingServer() 
{ 
	printf(".....PingServer is destructed.\n"); 
//	Sleep(1000);	 
 
} 
 
 
bool  
PingServer::analizePingPacket(char *pChar, int dataLen) 
{ 
	char* _pChar = pChar; 
 
	struct ethhdr *_ethhdr; 
	_ethhdr = (struct ethhdr *)_pChar;	 
	 
	// exchange ether address 
	unsigned char dummyMac[ETH_ALEN]; 
	 
	memcpy(dummyMac, _ethhdr->h_source, ETH_ALEN); 
	memcpy(_ethhdr->h_source, _ethhdr->h_dest, ETH_ALEN); 
	memcpy(_ethhdr->h_dest, dummyMac, ETH_ALEN); 
 
	// exchange IP address 
	_pChar += sizeof(struct ethhdr); 
	struct iphdr *_iphdr; 
	_iphdr = (struct iphdr *)_pChar; 
 
	__u32 dummyaddr; 
	 
	dummyaddr = _iphdr->saddr; 
	_iphdr->saddr = _iphdr->daddr; 
	_iphdr->daddr = dummyaddr; 
 
	// IP checksum 
	_iphdr->check = 0; 
	_iphdr->check = in_cksum((unsigned short *)_iphdr, sizeof(struct iphdr)); 
 
 
	// exchange ICMP header 
	_pChar += sizeof(struct iphdr); 
	struct icmphdr *_icmphdr; 
	_icmphdr = (struct icmphdr *)_pChar; 
 
	// must be Echo Request 
	if (_icmphdr->type != ICMP_ECHO) 
		return false; 
	 
	// change to Echo Reply 
	_icmphdr->type = ICMP_ECHOREPLY; 
 
	_icmphdr->checksum = 0; // should be 0 
	_icmphdr->checksum =  
		in_cksum((unsigned short *)_icmphdr,  
		ntohs(_iphdr->tot_len) - sizeof(struct iphdr)); 
 
	// Packet Release !! 
	m_pseudIF->releasePacket((void *)pChar, dataLen); 
 
	return true; 
 
};