ftpmgr.cpp

des加密算法

#include "stdafx.h"
#include "PIPMasq.h"

////////////////////////// FtpMgr /////////////////////////////////

FtpMgr::FtpMgr(
	TableMgr*	tableMgr,
	PortMgr*	portMgr,
	const char* pseudIPAddr
)
{
	m_tableMgr = tableMgr;
	m_portMgr = portMgr;
	memcpy(m_pseudIPAddr, pseudIPAddr, 16);
};

FtpMgr::~FtpMgr()
{
	printf(".....FtpMgr is destructed.\n");
//	Sleep(1000);	
}


void
FtpMgr::activeMode_out(char *pChar, int *dataLen, TableEntry* m_table)
{
	char *_pChar = pChar;


	_pChar += sizeof(struct ethhdr); 	
	struct iphdr *_iphdr = (struct iphdr *)_pChar;

	_pChar += sizeof(struct iphdr); 
	struct tcphdr *_tcphdr = (struct tcphdr *)_pChar;

	_pChar = _pChar + sizeof(struct tcphdr);

	// This "PORT" means the Port Number that the FTP server will use.
	// See RFC 959
	if (strncmp(_pChar, "PORT", 4) == 0)
	{
		_pChar += 5;  // skip "PORT" + one space
		char* _pChar_1 = _pChar;
		
		// Counter for the FTP message.
		int _counter = 0;
		
		// The tail of FTP message is "\r\n" ... Maybe,
		// I could not find the description in RFC959 
		while(1)
		{
			if ((*_pChar_1 == '\r') && (*(_pChar_1 + 1) == '\n'))
				break;
			
			_counter++;
			
			// "XXX,XXX,XXX,XXX,XXX,XXX" is the maximun data length
			if (_counter > 23) break; 
			
			_pChar_1++;
		}
		
		char _string[30];  // 30 is bigger than 23 
		
		memcpy(_string, _pChar, _counter);
		_string[_counter] = '\0';
		
		char seps[]   = ",.";
		char *token[6];
		
		//  (0) (1) (2) (3) (4) (5)
		// "XXX,XXX,XXX,XXX,XXX,XXX" 
		//                  ^^^ ^^^ <- Port Number information   
		
		token[0] = strtok( _string, seps );	
		//	strcpy(token[0], strtok( _string, seps ));	
		
		for(int i=1; i<6; i++)
		{
			token[i] = strtok( NULL, seps );
			//		strcpy(token[i], strtok( NULL, seps ));	
		}
		
		int _tcpDataPortNum_h = atoi(token[4]) * 256;	// (4)
		_tcpDataPortNum_h += atoi(token[5]);			// (5)
		
		
		char _pIPAddr[16];
		memcpy(_pIPAddr, m_pseudIPAddr, 16);
		
		token[0] = strtok(_pIPAddr, seps);
		
		for(i=1; i<4; i++)
		{
			token[i] = strtok( NULL, seps );
		}
		
		__u16 _tcpDataPortNum_n = htons(_tcpDataPortNum_h);
		
		// Port Number reservation
		__u16 _masqPort_n;
		if (! m_portMgr->reservPort(TCP, &_masqPort_n))
			return;
		
		// Table Management
		TableEntry _entry;

		_entry.diff_ack = 0;
		
		memcpy(&_entry, m_table, sizeof(TableEntry));
		
		_entry.expireTime = time(NULL) + EXPIRE_PERIOD;
		_entry.Protocol = TCP;
		_entry.masqPort = _masqPort_n;  // Masq port for network
		_entry.destPort = htons(FTP_DATA);	// ftp-data
		_entry.srcPort = _tcpDataPortNum_n; // TCP data port for network
		_entry.p_before = _entry.p_after = NULL;
		
		if (m_tableMgr->addEntry(&_entry) == false)
			return;
		// End of Table Management
		
		// Modify the packet
		__u16 __masqPort_h = htons(_masqPort_n);
		
		unsigned int _upper = __masqPort_h / 256;
		unsigned int _lower = __masqPort_h % 256;
		
		sprintf(_string, "%s,%s,%s,%s,%d,%d\r\n\0", 
			token[0],token[1],token[2],token[3],_upper,_lower);
		
		// printf("%s\n",_string);
		
		memcpy(_pChar, _string, strlen(_string));
		
		int _diffLen = strlen(_string) - _counter -2 ; // this "2" means "\r\n\"
		
		_iphdr->tot_len = htons(ntohs(_iphdr->tot_len) + _diffLen);

		_tcphdr->seq = htonl(ntohl(_tcphdr->seq) + m_table->diff_ack);
		
		m_table->diff_ack += _diffLen;  //After modification - before modification

		*dataLen += _diffLen;

		return;
	
	}
		
	_tcphdr->seq = htonl(ntohl(_tcphdr->seq) + m_table->diff_ack);

	return;
		
}