icmp6_pptr
(u_int32_t)ntohl(icp->icmp6_pptr));
icmp6->icmp6_pptr = htonl((u_int32_t)param);
mtu = ntohl(icmp6->icmp6_pptr);
icmp6->icmp6_code, ntohl(icmp6->icmp6_pptr));
ptr = ntohl(icmp6->icmp6_pptr);
if (ptr >= 0 && icmp6->icmp6_pptr != htonl(ptr)) {
htons(ntohl(icmp6->icmp6_pptr)), htons(ptr), 0);
icmp6->icmp6_pptr = htonl(ptr << 24);