rfc: netfilter: Unhide FWINV macro arguments ?

rfc: netfilter: Unhide FWINV macro arguments ?

[Joe Perches]

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

Re: rfc: netfilter: Unhide FWINV macro arguments ?

[Pablo Neira Ayuso]

On Thu, Jun 16, 2016 at 11:20:59AM -0700, Joe Perches wrote:
> There are several FWINV #defines with identical form
> that hide a specific structure variable and dereference
> it with a invflags member.

Right, this macro is obscure indeed.

> $ 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

I'll be taking a patch to sort out this. Thanks.

Re: rfc: netfilter: Unhide FWINV macro arguments ?

[Joe Perches]

On Fri, 2016-06-17 at 13:59 +0200, Pablo Neira Ayuso wrote:
> On Thu, Jun 16, 2016 at 11:20:59AM -0700, Joe Perches wrote:
> > There are several FWINV #defines with identical form
> > that hide a specific structure variable and dereference
> > it with a invflags member.
> Right, this macro is obscure indeed.
[]
> I'll be taking a patch to sort out this. Thanks.

I'll wait until you pick up or reject the
ether_addr_equal_masked patch as that changes
a few FWINV uses.