netfilter: nft_ct: add ct expectations support

Browse source

This patch allows to add, list and delete expectations via nft objref
infrastructure and assigning these expectations via nft rule.

This allows manual port triggering when no helper is defined to manage a
specific protocol. For example, if I have an online game which protocol
is based on initial connection to TCP port 9753 of the server, and where
the server opens a connection to port 9876, I can set rules as follow:

table ip filter {
    ct expectation mygame {
        protocol udp;
        dport 9876;
        timeout 2m;
        size 1;
    }

    chain input {
        type filter hook input priority 0; policy drop;
        tcp dport 9753 ct expectation set "mygame";
    }

    chain output {
        type filter hook output priority 0; policy drop;
        udp dport 9876 ct status expected accept;
    }
}

Signed-off-by: Stéphane Veyret <sveyret@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

...

This commit is contained in:

Stéphane Veyret 2019-05-25 15:30:58 +02:00 • committed by Pablo Neira Ayuso

parent 16e6427c88

commit 857b46027d

2 changed files with 149 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

14

include/uapi/linux/netfilter/nf_tables.h

View file

138

net/netfilter/nft_ct.c

View file