On Sat, Jul 13, 2019 at 07:23:27PM +0200, Florian Westphal wrote:
> Problem: Its not possible to easily match both udp and tcp in a single
> rule.
>
> ... input ip protocol { tcp,udp } dport 53
>
> will not work, as bison expects "tcp dport" or "sctp dport", or any
> other transport protocol name.
>
> Its possible to match the sport and dport via raw payload expressions,
> e.g.:
> ... input ip protocol { tcp,udp } @th,16,16 53
>
> but its not very readable.
> Furthermore, its not possible to use this for set definitions:
>
> table inet filter {
> set myset {
> type ipv4_addr . inet_proto . inet_service
> }
>
> chain forward {
> type filter hook forward priority filter; policy accept;
> ip daddr . ip protocol . @th,0,16 @myset
> }
> }
> # nft -f test
> test:7:26-35: Error: can not use variable sized data types (integer) in
> concat expressions
>
> During the netfilter workshop Pablo suggested to add an alias to do raw
> sport/dport matching more readable, and make it use the inet_service
> type automatically.
>
> So, this change makes @th,0,16 work for the set definition case by
> setting the data type to inet_service.
>
> A new "th s|dport" syntax is provided as readable alternative:
>
> ip protocol { tcp, udp } th dport 53
>
> As "th" is an alias for the raw expression, no dependency is
> generated -- its the users responsibility to add a suitable test to
> select the l4 header types that should be matched.
>
> Suggested-by: Pablo Neira Ayuso <[email protected]>
> Signed-off-by: Florian Westphal <[email protected]>
Acked-by: Pablo Neira Ayuso <[email protected]>
Thanks Florian.
