nftables vmap concatenations with interval

nftables vmap concatenations with interval

[Martin Bednar]

hi, 

using nftables, I want to create a vmap : 

map mymap {type ipv4_addr . iface_index : verdict }

I'd like the first argument to be an ip range/ network, so that I can add like 
so :
nft add element inet filter mymap { 172.18.0.1/24 . eth0 : accept }
or
nft add element inet filter mymap { 172.18.0.1-172.18.0.255 . eth0 : accept }

Any hints as to what to do it?

Thanks,

Martin.

Re: nftables vmap concatenations with interval

[Pablo Neira Ayuso]

On Tue, Sep 27, 2016 at 05:10:45PM +0200, Martin Bednar wrote:
> hi, 
> 
> using nftables, I want to create a vmap : 
> 
> map mymap {type ipv4_addr . iface_index : verdict }
> 
> I'd like the first argument to be an ip range/ network, so that I can add like 
> so :
> nft add element inet filter mymap { 172.18.0.1/24 . eth0 : accept }
>
> nft add element inet filter mymap { 172.18.0.1-172.18.0.255 . eth0 : accept }
> 
> Any hints as to what to do it?

nft add table inet filter
nft add map inet filter mymap { type ipv4_addr . iface_index : verdict \; }
nft add element inet filter mymap { 172.18.0.0  . eth0 : accept }
nft add rule inet filter forward ip saddr and 255.255.255.0 . iif vmap @mymap
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^

The idea here is to mask the address, then add to the set the result
of this operation, thus, 172.18.0.0

Re: nftables vmap concatenations with interval

[Martin Bednar]

Le Tuesday, September 27, 2016 9:11:01 PM CEST Pablo Neira Ayuso a écrit :
> 
> nft add table inet filter
> nft add map inet filter mymap { type ipv4_addr . iface_index : verdict \; }
> nft add element inet filter mymap { 172.18.0.0  . eth0 : accept }
> nft add rule inet filter forward ip saddr and 255.255.255.0 . iif vmap
> @mymap ^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> The idea here is to mask the address, then add to the set the result
> of this operation, thus, 172.18.0.0

Very cool trick... Thanks. this solves 90% of what I want :)
This however implies the same mask for all networks, right?
Is is somehow possible to have one vmap for networks with different masks?

Thanks.