Re: [RFC PATCH net-next 6/6 v2] net/sched: act_ct: Add tc recirc id set/del support

[Marcelo Leitner <mleitner@redhat.com>]

On Tue, Jan 29, 2019 at 10:02:06AM +0200, Paul Blakey wrote:
> Set or clears (free) the skb tc recirc id extension.
> If used with OVS, OVS can clear this recirc id after it reads it.
> 
> Signed-off-by: Paul Blakey <paulb@mellanox.com>
> ---
>  include/net/tc_act/tc_ct.h        |  2 ++
>  include/uapi/linux/tc_act/tc_ct.h |  2 ++
>  net/sched/act_ct.c                | 18 ++++++++++++++++++
>  3 files changed, 22 insertions(+)
> 
> diff --git a/include/net/tc_act/tc_ct.h b/include/net/tc_act/tc_ct.h
> index 4a16375..6ea19d8 100644
> --- a/include/net/tc_act/tc_ct.h
> +++ b/include/net/tc_act/tc_ct.h
> @@ -16,6 +16,8 @@ struct tcf_ct {
>  	u32 mark_mask;
>  	u16 zone;
>  	bool commit;
> +	uint32_t set_recirc;
> +	bool del_recirc;
>  };
>  
>  #define to_ct(a) ((struct tcf_ct *)a)
> diff --git a/include/uapi/linux/tc_act/tc_ct.h b/include/uapi/linux/tc_act/tc_ct.h
> index 6dbd771..2279a9b 100644
> --- a/include/uapi/linux/tc_act/tc_ct.h
> +++ b/include/uapi/linux/tc_act/tc_ct.h
> @@ -14,6 +14,8 @@ struct tc_ct {
>  	__u32 labels_mask[4];
>  	__u32 mark;
>  	__u32 mark_mask;
> +	uint32_t set_recirc;
> +	bool del_recirc;
>  	bool commit;
>  };

Have you considered adding a specific action for this? Asking because
setting recirc_id can be useful outside of ct context too: decap, set
recirc_id, reclassify.

>  
> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
> index 61155cc..7822385 100644
> --- a/net/sched/act_ct.c
> +++ b/net/sched/act_ct.c
> @@ -117,6 +117,11 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
>  	u_int8_t family;
>  	bool cached;
>  
> +	if (ca->del_recirc) {
> +		skb_ext_del(skb, SKB_EXT_TC_RECIRC_ID);
> +		return ca->tcf_action;
> +	}
> +
>  	/* The conntrack module expects to be working at L3. */
>  	nh_ofs = skb_network_offset(skb);
>  	skb_pull_rcsum(skb, nh_ofs);
> @@ -243,6 +248,15 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
>  	skb_postpush_rcsum(skb, skb->data, nh_ofs);
>  
>  	spin_unlock(&ca->tcf_lock);
> +
> +	if (ca->set_recirc) {
> +		u32 recirc = ca->set_recirc;
> +		uint32_t *recircp = skb_ext_add(skb, SKB_EXT_TC_RECIRC_ID);
> +
> +		if (recircp)
> +			*recircp = recirc;
> +	}
> +
>  	return ca->tcf_action;
>  
>  drop:
> @@ -305,6 +319,8 @@ static int tcf_ct_init(struct net *net, struct nlattr *nla,
>  		ci->net = net;
>  		ci->commit = parm->commit;
>  		ci->zone = parm->zone;
> +		ci->set_recirc = parm->set_recirc;
> +		ci->del_recirc = parm->del_recirc;
>  #if !IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
>  		if (parm->mark_mask) {
>  			NL_SET_ERR_MSG_MOD(extack, "Mark not supported by kernel config");
> @@ -378,6 +394,8 @@ static inline int tcf_ct_dump(struct sk_buff *skb, struct tc_action *a,
>  	opt.mark_mask = ci->mark_mask,
>  	memcpy(opt.labels, ci->labels, sizeof(opt.labels));
>  	memcpy(opt.labels_mask, ci->labels_mask, sizeof(opt.labels_mask));
> +	opt.set_recirc = ci->set_recirc;
> +	opt.del_recirc = ci->del_recirc;
>  
>  	if (nla_put(skb, TCA_CT_PARMS, sizeof(opt), &opt))
>  		goto nla_put_failure;
> -- 
> 1.8.3.1
>