ipfw_chg_hook
CTLFLAG_NEEDGIANT, &VNET_NAME(fw6_enable), 0, ipfw_chg_hook, "I",
CTLFLAG_NEEDGIANT, &VNET_NAME(fwlink_enable), 0, ipfw_chg_hook, "I",
int ipfw_chg_hook(SYSCTL_HANDLER_ARGS);
CTLFLAG_NEEDGIANT, &VNET_NAME(fw_enable), 0, ipfw_chg_hook, "I",