Commit cd11b164 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

net/tc: introduce TC_ACT_REINSERT. 



This is similar TC_ACT_REDIRECT, but with a slightly different
semantic:
- on ingress the mirred skbs are passed to the target device
network stack without any additional check not scrubbing.
- the rcu-protected stats provided via the tcf_result struct
  are updated on error conditions.

This new tcfa_action value is not exposed to the user-space
and can be used only internally by clsact.

v1 -> v2: do not touch TC_ACT_REDIRECT code path, introduce
 a new action type instead
v2 -> v3:
 - rename the new action value TC_ACT_REINJECT, update the
   helper accordingly
 - take care of uncloned reinjected packets in XDP generic
   hook
v3 -> v4:
 - renamed again the new action value (JiriP)
v4 -> v5:
 - fix build error with !NET_CLS_ACT (kbuild bot)

Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7fd4b288

include/net/pkt_cls.h

+3 −0
Original line number Diff line number Diff line
@@ -7,6 +7,9 @@ 
#include <net/sch_generic.h>

#include <net/act_api.h>



/* TC action not accessible from user space */

#define TC_ACT_REINSERT		(TC_ACT_VALUE_MAX + 1)



/* Basic packet classifier frontend definitions. */



struct tcf_walker {

include/net/sch_generic.h

+28 −0
Original line number Diff line number Diff line
@@ -235,6 +235,12 @@ struct tcf_result { 
			u32		classid;

		};

		const struct tcf_proto *goto_tp;



		/* used by the TC_ACT_REINSERT action */

		struct {

			bool		ingress;

			struct gnet_stats_queue *qstats;

		};

	};

};
@@ -569,6 +575,15 @@ static inline void skb_reset_tc(struct sk_buff *skb) 
#endif

}



static inline bool skb_is_tc_redirected(const struct sk_buff *skb)

{

#ifdef CONFIG_NET_CLS_ACT

	return skb->tc_redirected;

#else

	return false;

#endif

}



static inline bool skb_at_tc_ingress(const struct sk_buff *skb)

{

#ifdef CONFIG_NET_CLS_ACT
@@ -1108,4 +1123,17 @@ void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, 
void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,

			  struct mini_Qdisc __rcu **p_miniq);



static inline void skb_tc_reinsert(struct sk_buff *skb, struct tcf_result *res)

{

	struct gnet_stats_queue *stats = res->qstats;

	int ret;



	if (res->ingress)

		ret = netif_receive_skb(skb);

	else

		ret = dev_queue_xmit(skb);

	if (ret && stats)

		qstats_overlimit_inc(res->qstats);

}



#endif

net/core/dev.c

+5 −1
Original line number Diff line number Diff line
@@ -4252,7 +4252,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, 
	/* Reinjected packets coming from act_mirred or similar should

	 * not get XDP generic processing.

	 */

	if (skb_cloned(skb))

	if (skb_cloned(skb) || skb_is_tc_redirected(skb))

		return XDP_PASS;



	/* XDP packets must be linear and must have sufficient headroom
@@ -4602,6 +4602,10 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret, 
		__skb_push(skb, skb->mac_len);

		skb_do_redirect(skb);

		return NULL;

	case TC_ACT_REINSERT:

		/* this does not scrub the packet, and updates stats on error */

		skb_tc_reinsert(skb, &cl_res);

		return NULL;

	default:

		break;

	}

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