Winsock and C problem

[debasishgang7]

Hi guys here is my problem.I am trying to send ICMP packets to a HOST using WINSOK.So here is my code:

#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <stdlib.h>

#define IP_RECORD_ROUTE  0x7
// 
// IP header structure
//
typedef struct _iphdr 
{
    unsigned int   h_len:4;        // Length of the header
    unsigned int   version:4;      // Version of IP
    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;
    unsigned int   destIP;
} IpHeader;

#define ICMP_ECHO        8
#define ICMP_ECHOREPLY   0
#define ICMP_MIN         8 // Minimum 8-byte ICMP packet (header)

//
// ICMP header structure
//
typedef struct _icmphdr 
{
    BYTE   i_type;
    BYTE   i_code;                 // Type sub code
    USHORT i_cksum;
    USHORT i_id;
    USHORT i_seq;
    // This is not the standard header, but we reserve space for time
    ULONG  timestamp;
} IcmpHeader;

//
// IP option header--use with socket option IP_OPTIONS
//
typedef struct _ipoptionhdr
{
    unsigned char        code;        // Option type
    unsigned char        len;         // Length of option hdr
    unsigned char        ptr;         // Offset into options
    unsigned long        addr[9];     // List of IP addrs
} IpOptionHeader;

#define DEF_PACKET_SIZE  32        // Default packet size
#define MAX_PACKET       1024      // Max ICMP packet size
#define MAX_IP_HDR_SIZE  60       // Max IP header size w/options

BOOL  bRecordRoute;
int   datasize;
char *lpdest;

void FillICMPData(char *icmp_data, int datasize)
{
    IcmpHeader *icmp_hdr = NULL;
    char       *datapart = NULL;

    icmp_hdr = (IcmpHeader*)icmp_data;
    icmp_hdr->i_type = ICMP_ECHO;        // Request an ICMP echo
    icmp_hdr->i_code = 0;
    icmp_hdr->i_id = (USHORT)GetCurrentProcessId();
    icmp_hdr->i_cksum = 0;
    icmp_hdr->i_seq = 0;
  
    datapart = icmp_data + sizeof(IcmpHeader);
    //
    // Place some junk in the buffer
    //
    memset(datapart,'I', datasize - sizeof(IcmpHeader));
}


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);
}
        
int main()
{

    WSADATA            wsaData;
    SOCKET             sockRaw = INVALID_SOCKET;
    struct sockaddr_in dest,from;
    int                bread,
                       fromlen = sizeof(from),
                       timeout = 1000,
                       ret;
    char              *icmp_data = "AAAA",
                      *recvbuf = NULL;
    unsigned int       addr = 0;
    USHORT             seq_no = 0;
    struct hostent    *hp = NULL;
    IpOptionHeader     ipopt;


    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("WSAStartup() failed: %d\n", GetLastError());
        return -1;
    }


    sockRaw = WSASocket (AF_INET, SOCK_RAW, IPPROTO_ICMP, NULL, 0,WSA_FLAG_OVERLAPPED);
    if (sockRaw == INVALID_SOCKET) 
    {
        printf("WSASocket() failed: %d\n", WSAGetLastError());
        return -1;
    }
    if (bRecordRoute)
    {
        // Setup the IP option header to go out on every ICMP packet
        //
        ZeroMemory(&ipopt, sizeof(ipopt));
        ipopt.code = IP_RECORD_ROUTE; // Record route option
        ipopt.ptr  = 4;               // Point to the first addr offset
        ipopt.len  = 39;              // Length of option header
  
        ret = setsockopt(sockRaw, IPPROTO_IP, IP_OPTIONS, (char *)&ipopt, sizeof(ipopt));
        if (ret == SOCKET_ERROR)
        {
            printf("setsockopt(IP_OPTIONS) failed: %d\n", WSAGetLastError());
        }
    }
    // Set the send/recv timeout values
    //
    bread = setsockopt(sockRaw, SOL_SOCKET, SO_RCVTIMEO, (char*)&timeout, sizeof(timeout));
    if(bread == SOCKET_ERROR) 
    {
        printf("setsockopt(SO_RCVTIMEO) failed: %d\n", WSAGetLastError());
        return -1;
    }
    timeout = 1000;
    bread = setsockopt(sockRaw, SOL_SOCKET, SO_SNDTIMEO, (char*)&timeout, sizeof(timeout));
    if (bread == SOCKET_ERROR) 
    {
        printf("setsockopt(SO_SNDTIMEO) failed: %d\n", WSAGetLastError());
        return -1;
    }
    memset(&dest, 0, sizeof(dest));
    //
    // Resolve the endpoint's name if necessary
    //
    char *lpdest = "192.168.157.128";
    dest.sin_family = AF_INET;
    if ((dest.sin_addr.s_addr = inet_addr(lpdest)) == INADDR_NONE)
    {
        if ((hp = gethostbyname(lpdest)) != NULL)
        {
            memcpy(&(dest.sin_addr), hp->h_addr, hp->h_length);
            dest.sin_family = hp->h_addrtype;
            printf("dest.sin_addr = %s\n", inet_ntoa(dest.sin_addr));
        }
        else
        {
            printf("gethostbyname() failed: %d\n", 
                WSAGetLastError());
            return -1;
        }
    }        

    // 
    // Create the ICMP packet
    //       
    datasize += sizeof(IcmpHeader);  

    icmp_data = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY,MAX_PACKET);
    if (!icmp_data) 
    {
        printf("HeapAlloc() failed: %d\n", GetLastError());
        return -1;
    }
    memset(icmp_data,0,MAX_PACKET);
    FillICMPData(icmp_data,datasize);
    //
    // Start sending/receiving ICMP packets
    //
    while(1) 
    {
        static int nCount = 0;
        int        bwrote;
                
        if (nCount++ == 1) 
            break;
                
        ((IcmpHeader*)icmp_data)->i_cksum = 0;
        ((IcmpHeader*)icmp_data)->timestamp = GetTickCount();
        ((IcmpHeader*)icmp_data)->i_seq = seq_no++;
        ((IcmpHeader*)icmp_data)->i_cksum = checksum((USHORT*)icmp_data, datasize);

        bwrote = sendto(sockRaw, icmp_data, datasize, 0, (struct sockaddr*)&dest, sizeof(dest));
        if (bwrote == SOCKET_ERROR)
        {
            if (WSAGetLastError() == WSAETIMEDOUT) 
            {
                printf("timed out\n");
                continue;
            }
            printf("sendto() failed: %d\n", WSAGetLastError());
            return -1;
        }
        if (bwrote < datasize) 
        {
            printf("Wrote %d bytes\n", bwrote);
        }

        Sleep(1000);
    }
    // Cleanup
    //
    if (sockRaw != INVALID_SOCKET) 
        closesocket(sockRaw);
    HeapFree(GetProcessHeap(), 0, recvbuf);
    HeapFree(GetProcessHeap(), 0, icmp_data);

    WSACleanup();
    return 0;
}

If you see the sniffed traffic (a screen shot i have attached)you can see that the program is also sending some trailer (some 00 s)with the ICMP packet.
Can anyone please tell me what changes i should made to the code to remove the trailer part of the packet??And send my desired data(payload) with the ICMP packet.