((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 outn");
　　continue;
　　}
　　fprintf(stderr,"sendto failed: %dn",WSAGetLastError());
　　ExitProcess(STATUS_FAILED);
　　}
　　if (bwrote < datasize ) {
　　fprintf(stdout,"Wrote %d bytesn",bwrote);
　　}
　　bread = recvfrom(sockRaw,recvbuf,MAX_PACKET,0,(struct sockaddr*)&from,
　　&fromlen);
　　if (bread == SOCKET_ERROR){
　　if (WSAGetLastError() == WSAETIMEDOUT) {
　　printf("timed outn");
　　continue;
　　}
　　fprintf(stderr,"recvfrom failed: %dn",WSAGetLastError());
　　ExitProcess(STATUS_FAILED);
　　}
　　decode_resp(recvbuf,bread,&from);
　　Sleep(1000);
　　
　　}
　　return 0;
　　
　　}
　　/*
　　The response is an IP packet. We must decode the IP header to locate
　　the ICMP data
　　*/
　　void decode_resp(char *buf, int bytes,struct sockaddr_in *from) {
　　
　　IpHeader *iphdr;
　　IcmpHeader *icmphdr;
　　unsigned short iphdrlen;
　　
　　iphdr = (IpHeader *)buf;
　　
　　iphdrlen = iphdr->h_len * 4 ; // number of 32-bit words *4 = bytes
　　
　　if (bytes < iphdrlen + ICMP_MIN) {
　　printf("Too few bytes from %sn",inet_ntoa(from->sin_addr));
　　}
　　
　　icmphdr = (IcmpHeader*)(buf + iphdrlen);
　　
　　if (icmphdr->i_type != ICMP_ECHOREPLY) {
　　fprintf(stderr,"non-echo type %d recvdn",icmphdr->i_type);
　　return;
　　}
　　if (icmphdr->i_id != (USHORT)GetCurrentProcessId()) {
　　fprintf(stderr,"someone else's packet!n");
　　return ;
　　}
　　printf("%d bytes from %s:",bytes, inet_ntoa(from->sin_addr));
　　printf(" icmp_seq = %d. ",icmphdr->i_seq);
　　printf(" time: %d ms ",GetTickCount()-icmphdr->timestamp);
　　printf("n");
　　
　　}