There are several FWINV #defines with identical form that hide a specific structure variable and dereference it with a invflags member.
$ git grep "define FWINV" include/linux/netfilter_bridge/ebtables.h:#define FWINV(bool,invflg) ((bool) ^ !!(info->invflags & invflg)) net/bridge/netfilter/ebtables.c:#define FWINV2(bool, invflg) ((bool) ^ !!(e->invflags & invflg)) net/ipv4/netfilter/arp_tables.c:#define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg))) net/ipv4/netfilter/ip_tables.c:#define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg))) net/ipv6/netfilter/ip6_tables.c:#define FWINV(bool, invflg) ((bool) ^ !!(ip6info->invflags & (invflg))) net/netfilter/xt_tcpudp.c:#define FWINVTCP(bool, invflg) ((bool) ^ !!(tcpinfo->invflags & (invflg))) It might make sense to use a new macro like: #define INVFLAG(var, test, invflag) \ ((test) ^ !!((var)->invflags & (invflag))) and convert all the various FWINV style uses $ git grep --name-only "\bFWINV" include/linux/netfilter_bridge/ebtables.h net/bridge/netfilter/ebt_802_3.c net/bridge/netfilter/ebt_arp.c net/bridge/netfilter/ebt_ip.c net/bridge/netfilter/ebt_ip6.c net/bridge/netfilter/ebt_stp.c net/bridge/netfilter/ebtables.c net/ipv4/netfilter/arp_tables.c net/ipv4/netfilter/ip_tables.c net/ipv6/netfilter/ip6_tables.c net/netfilter/xt_tcpudp.c $ git grep "\bFWINV" | grep -v "#" | wc -l 65