Re: [PATCH nf] netfilter: nft_connlimit: fix duplicated tracking of a connection

[Florian Westphal <fw@strlen.de>]

Fernando Fernandez Mancera <fmancera@suse.de> wrote:
> Connlimit expression can be used for all kind of packets and not only
> for packets with connection state new. See this ruleset as example:
> 
> table ip filter {
>         chain input {
>                 type filter hook input priority filter; policy accept;
>                 tcp dport 22 ct count over 4 counter
>         }
> }

Right.  Would you mind sending a patch for nftables documentation to
recommend combining this with ct state new or similar?

> +	if (ctinfo == IP_CT_NEW) {
> +		if (nf_conncount_add(nft_net(pkt), priv->list, tuple_ptr, zone)) {
> +			regs->verdict.code = NF_DROP;
> +			return;
> +		}
> +	} else {
> +		local_bh_disable();
> +		nf_conncount_gc_list(nft_net(pkt), priv->list);
> +		local_bh_enable();

LGTM, we could make a __nf_conncount_gc_list and make
nf_conncount_gc_list not need BH disable (and do the jiffies
check first w.o. BH disable) but I think in the interest of
a small patch and given that we should not be dealing with
!new packets anyway I think this change is fine.

Thanks Fernando for fixing this up.