ip->ip_sum = compute_ip_checksum(ip, IP_HDR_SIZE);
icmph->type = ICMP_ECHO_REPLY;
icmph->checksum = 0;
icmph->checksum = compute_ip_checksum(icmph, len - IP_HDR_SIZE);
ip->ip_sum = compute_ip_checksum(ip, IP_HDR_SIZE);
icmph->type = ICMP_ECHO_REPLY;
icmph->checksum = 0;
icmph->checksum = compute_ip_checksum(icmph, len - IP_HDR_SIZE);