Re: [PATCH net-next v6 2/3] net/sched: act_ct: Offload established connections to flow table

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Tue, Mar 03, 2020 at 05:57:51PM +0200, Paul Blakey wrote:
> Add a ft entry when connections enter an established state and delete
> the connections when they leave the established state.
> 
> The flow table assumes ownership of the connection. In the following
> patch act_ct will lookup the ct state from the FT. In future patches,
> drivers will register for callbacks for ft add/del events and will be
> able to use the information to offload the connections.
> 
> Note that connection aging is managed by the FT.
> 
> Signed-off-by: Paul Blakey <paulb@mellanox.com>
> Acked-by: Jiri Pirko <jiri@mellanox.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
>  net/sched/act_ct.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
> 
> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
> index 3321087..2ab38431 100644
> --- a/net/sched/act_ct.c
> +++ b/net/sched/act_ct.c
> @@ -125,6 +125,67 @@ static void tcf_ct_flow_table_put(struct tcf_ct_params *params)
>  	spin_unlock_bh(&zones_lock);
>  }
>  
> +static void tcf_ct_flow_table_add(struct tcf_ct_flow_table *ct_ft,
> +				  struct nf_conn *ct,
> +				  bool tcp)
> +{
> +	struct flow_offload *entry;
> +	int err;
> +
> +	if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
> +		return;
> +
> +	entry = flow_offload_alloc(ct);
> +	if (!entry) {
> +		WARN_ON_ONCE(1);
> +		goto err_alloc;
> +	}
> +
> +	if (tcp) {
> +		ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
> +		ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
> +	}
> +
> +	err = flow_offload_add(&ct_ft->nf_ft, entry);
> +	if (err)
> +		goto err_add;
> +
> +	return;
> +
> +err_add:
> +	flow_offload_free(entry);
> +err_alloc:
> +	clear_bit(IPS_OFFLOAD_BIT, &ct->status);
> +}
> +
> +static void tcf_ct_flow_table_process_conn(struct tcf_ct_flow_table *ct_ft,
> +					   struct nf_conn *ct,
> +					   enum ip_conntrack_info ctinfo)
> +{
> +	bool tcp = false;
> +
> +	if (ctinfo != IP_CT_ESTABLISHED && ctinfo != IP_CT_ESTABLISHED_REPLY)
> +		return;
> +
> +	switch (nf_ct_protonum(ct)) {
> +	case IPPROTO_TCP:
> +		tcp = true;
> +		if (ct->proto.tcp.state != TCP_CONNTRACK_ESTABLISHED)
> +			return;
> +		break;
> +	case IPPROTO_UDP:
> +		break;
> +	default:
> +		return;
> +	}
> +
> +	if (nf_ct_ext_exist(ct, NF_CT_EXT_HELPER) ||
> +	    ct->status & IPS_SEQ_ADJUST)
> +		return;
> +
> +	tcf_ct_flow_table_add(ct_ft, ct, tcp);
> +}
> +
>  static int tcf_ct_flow_tables_init(void)
>  {
>  	return rhashtable_init(&zones_ht, &zones_params);
> @@ -578,6 +639,8 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
>  		nf_conntrack_confirm(skb);
>  	}
>  
> +	tcf_ct_flow_table_process_conn(p->ct_ft, ct, ctinfo);
> +
>  out_push:
>  	skb_push_rcsum(skb, nh_ofs);
>  
> -- 
> 1.8.3.1
>