IPV6_FW_IP6OPT_NONXT
if (chain->fw_ip6opt & IPV6_FW_IP6OPT_NONXT) PRINTOPT("nonxt");
if (chain->fw_ip6nopt & IPV6_FW_IP6OPT_NONXT) PRINTOPT("!nonxt");
if (!strncmp(p,"nonxt",strlen(p))) *d |= IPV6_FW_IP6OPT_NONXT;
opts &= ~IPV6_FW_IP6OPT_NONXT;
nopts &= ~IPV6_FW_IP6OPT_NONXT;