#include <stdio.h>
#include <winsock2.h>


#pragma comment(lib, "Ws2_32.lib");

typedef struct iphdr 
{

	unsigned char  verlen;			// IP version & length
	unsigned char  tos;				// Type of service
	unsigned short total_len;		// Total length of the packet
	unsigned short ident;			// Unique identifier
	unsigned short frag_and_flags;	// Flags
	unsigned char  ttl;				// Time to live
	unsigned char  proto;			// Protocol (TCP, UDP etc)
	unsigned short checksum;		// IP checksum
	unsigned int   sourceIP;		// Source IP
	unsigned int   destIP;			// Destination IP

} IPHEADER;


typedef struct tcphdr 
{

	unsigned short sport;			// Source port
	unsigned short dport;			// Destination port
	unsigned int   seq;				// Sequence number
	unsigned int   ack_seq;			// Acknowledgement number
	unsigned char  lenres;			// Length return size
	unsigned char  flags;			// Flags and header length
	unsigned short window;			// Window size
	unsigned short checksum;		// Packet Checksum
	unsigned short urg_ptr;			// Urgent Pointer

} TCPHEADER;


// Our pseudo header struct
typedef struct pshdr
{

	unsigned int   saddr;			// Source address
	unsigned int   daddr;			// Destination address
	unsigned char  zero;			// Placeholder
	unsigned char  proto;			// Protocol
	unsigned short length;			// TCP length
	struct tcphdr tcp;				// TCP Header struct

} PSDHEADER;



struct InfoPacket
{

	char srcIP[256];
	char dstIP[256];
	int ttl;
	int srcPort;
	int dstPort;
};




USHORT checksum(USHORT *buffer, int size)
{
    unsigned long cksum=0;

    while (size > 1) {
        cksum += *buffer++;
        size  -= sizeof(USHORT);   
    }

    if (size)
        cksum += *(UCHAR*)buffer;   

    cksum = (cksum >> 16) + (cksum & 0xffff);
    cksum += (cksum >>16); 

    return (USHORT)(~cksum); 
}



unsigned long ResolveAddress(char *szHost)
{
	unsigned long IP = inet_addr(szHost);
	if (IP==INADDR_NONE) {
		hostent *pHE = gethostbyname(szHost);
		if (pHE == 0) 
			return INADDR_NONE;
		IP = *((unsigned long *)pHE->h_addr_list[0]);	
	}

	return IP;
}









int main(void)
{
	IPHEADER ipHeader; 
	TCPHEADER tcpHeader; 
	PSDHEADER psdHeader;
	struct InfoPacket inf;
 
	char szSendBuf[60]={0},buf[64]; 
	int rect;

	WSADATA WSAData; 
	if (WSAStartup(MAKEWORD(2,2), &WSAData) != 0)
		return FALSE; 
 
	SOCKET sock; 
	if ((sock = WSASocket(AF_INET,SOCK_RAW,IPPROTO_RAW,NULL,0, 0x01)) == INVALID_SOCKET) {
		WSACleanup();
		return FALSE; 
	}

	BOOL flag=TRUE;
	if (setsockopt(sock,IPPROTO_IP,2,(char *)&flag,sizeof(flag)) == SOCKET_ERROR) {
		closesocket(sock);
		WSACleanup();
		return FALSE; 
	}


	printf("Podaj adres IP zrodlowy: \n");
	scanf("%s", &inf.srcIP);
	printf("Podaj adres IP docelowy: \n");
	scanf("%s", &inf.dstIP);
	printf("Podaj czas zycia pakietu (TTL): \n");
	scanf("%s", &inf.ttl);
	printf("Podaj port docelowy: \n");
	scanf("%s", &inf.dstPort);
	printf("Podaj port zrodlowy: \n");
	scanf("%s", &inf.srcPort);

	SOCKADDR_IN ssin; 
	memset(&ssin, 0, sizeof(ssin));
	ssin.sin_family=AF_INET;
	ssin.sin_port=htons(133);
	ssin.sin_addr.s_addr=ResolveAddress("192.168.0.2");

	ipHeader.verlen=(4<<4 | sizeof(ipHeader)/sizeof(unsigned long));
	ipHeader.total_len=htons(sizeof(ipHeader)+sizeof(tcpHeader));
	ipHeader.ident=1;
	ipHeader.frag_and_flags=0;
	ipHeader.ttl=inf.ttl;
	ipHeader.proto=IPPROTO_TCP;
	ipHeader.checksum=0;
	ipHeader.destIP=ResolveAddress(inf.dstIP);
	ipHeader.sourceIP=ResolveAddress(inf.srcIP);

	tcpHeader.dport=htons(inf.dstPort);
	tcpHeader.ack_seq=0;
	tcpHeader.lenres=(sizeof(tcpHeader)/4<<4|0); 
	tcpHeader.flags=2; 
	tcpHeader.window=htons(16384); 
	tcpHeader.urg_ptr=0; 


	tcpHeader.checksum=0; 
	tcpHeader.sport=htons(inf.srcPort);
	tcpHeader.seq=htons((unsigned short)((rand() << 16) | rand()));

	psdHeader.daddr=ipHeader.destIP; 
	psdHeader.zero=0; 
	psdHeader.proto=IPPROTO_TCP; 
	psdHeader.length=htons(sizeof(tcpHeader));
	psdHeader.saddr=ipHeader.sourceIP; 

	

	memcpy(szSendBuf, &psdHeader, sizeof(psdHeader)); 
	memcpy(szSendBuf+sizeof(psdHeader), &tcpHeader, sizeof(tcpHeader));
		
	tcpHeader.checksum=checksum((USHORT *)szSendBuf,sizeof(psdHeader)+sizeof(tcpHeader)); 
 
	memcpy(szSendBuf, &ipHeader, sizeof(ipHeader)); 
	memcpy(szSendBuf+sizeof(ipHeader), &tcpHeader, sizeof(tcpHeader)); 
	memset(szSendBuf+sizeof(ipHeader)+sizeof(tcpHeader), 0, 4); 

	ipHeader.checksum=checksum((USHORT *)szSendBuf, sizeof(ipHeader)+sizeof(tcpHeader)); 
 
	memcpy(szSendBuf, &ipHeader, sizeof(ipHeader)); 
	rect=sendto(sock, szSendBuf, sizeof(ipHeader)+sizeof(tcpHeader),0,(LPSOCKADDR)&ssin, sizeof(ssin));
	if (rect==SOCKET_ERROR) {
		sprintf(buf, "[SYN]: Send error: <%d>.",WSAGetLastError());


		closesocket(sock);
		WSACleanup();
		return 0;
	}


	closesocket(sock); 
	WSACleanup(); 

	return 0;
}