XT_TCP_INV_MASK 49 include/uapi/linux/netfilter_ipv4/ip_tables.h #define IPT_TCP_INV_MASK XT_TCP_INV_MASK XT_TCP_INV_MASK 49 include/uapi/linux/netfilter_ipv6/ip6_tables.h #define IP6T_TCP_INV_MASK XT_TCP_INV_MASK XT_TCP_INV_MASK 126 net/netfilter/xt_tcpudp.c return (tcpinfo->invflags & ~XT_TCP_INV_MASK) ? -EINVAL : 0;