Does someone write the PING function with RPGIV instead of usingsystem PING command ?

Hi,
        Does someone write the checksum function for Socket ICMP ? Does
someone write native PING function with RPGIV instead of using PING
command ? I need to wrote PING function on ICMP message for Pthread
used, I  found the C checksum source , but I am not familarwith C
transferring to RPGIV ? Do any experts help me to transfer to RPGIV ?
The C source as following:

//
// Mike Muuss' in_cksum() function
// and his comments from the original
// ping program
//
// * Author -
// *    Mike Muuss
// *    U. S. Army Ballistic Research Laboratory
// *    December, 1983

/*
 *                      I N _ C K S U M
 *
 * Checksum routine for Internet Protocol family headers (C Version)
 *
 */
u_short in_cksum(u_short *addr, int len)
{
        register int nleft = len;
        register u_short *w = addr;
        register u_short answer;
        register int sum = 0;

        /*
         *  Our algorithm is simple, using a 32 bit accumulator (sum),
         *  we add sequential 16 bit words to it, and at the end, fold
         *  back all the carry bits from the top 16 bits into the lower
         *  16 bits.
         */
        while( nleft > 1 )  {
                sum += *w++;
                nleft -= 2;
        }

        /* mop up an odd byte, if necessary */
        if( nleft == 1 ) {
                u_short u = 0;

                *(u_char *)(&u) = *(u_char *)w ;
                sum += u;
        }

        /*
         * add back carry outs from top 16 bits to low 16 bits
         */
        sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16
*/
        sum += (sum >> 16);                     /* add carry */
        answer = ~sum;                          /* truncate to 16 bits
*/
        return (answer);
}