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net: sched: refactor reinsert action

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The TC_ACT_REINSERT return type was added as an in-kernel only option to
allow a packet ingress or egress redirect. This is used to avoid
unnecessary skb clones in situations where they are not required. If a TC
hook returns this code then the packet is 'reinserted' and no skb consume
is carried out as no clone took place.

This return type is only used in act_mirred. Rather than have the reinsert
called from the main datapath, call it directly in act_mirred. Instead of
returning TC_ACT_REINSERT, change the type to the new TC_ACT_CONSUMED
which tells the caller that the packet has been stolen by another process
and that no consume call is required.

Moving all redirect calls to the act_mirred code is in preparation for
tracking recursion created by act_mirred.

Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Hurley 2019-06-24 23:13:35 +01:00 committed by David S. Miller
parent 5cdda5f1d6
commit 720f22fed8
4 changed files with 5 additions and 6 deletions
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2
include/net/pkt_cls.h
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@ -10,7 +10,7 @@
#include <net/net_namespace.h> #include <net/net_namespace.h>
/* TC action not accessible from user space */ /* TC action not accessible from user space */
#define TC_ACT_REINSERT (TC_ACT_VALUE_MAX + 1) #define TC_ACT_CONSUMED (TC_ACT_VALUE_MAX + 1)
/* Basic packet classifier frontend definitions. */ /* Basic packet classifier frontend definitions. */

2
include/net/sch_generic.h
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@ -279,7 +279,7 @@ struct tcf_result {
}; };
const struct tcf_proto *goto_tp; const struct tcf_proto *goto_tp;
/* used by the TC_ACT_REINSERT action */ /* used in the skb_tc_reinsert function */
struct { struct {
bool ingress; bool ingress;
struct gnet_stats_queue *qstats; struct gnet_stats_queue *qstats;

4
net/core/dev.c
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@ -4689,9 +4689,7 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
__skb_push(skb, skb->mac_len); __skb_push(skb, skb->mac_len);
skb_do_redirect(skb); skb_do_redirect(skb);
return NULL; return NULL;
case TC_ACT_REINSERT: case TC_ACT_CONSUMED:
/* this does not scrub the packet, and updates stats on error */
skb_tc_reinsert(skb, &cl_res);
return NULL; return NULL;
default: default:
break; break;

3
net/sched/act_mirred.c
View File

@ -277,7 +277,8 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
if (use_reinsert) { if (use_reinsert) {
res->ingress = want_ingress; res->ingress = want_ingress;
res->qstats = this_cpu_ptr(m->common.cpu_qstats); res->qstats = this_cpu_ptr(m->common.cpu_qstats);
return TC_ACT_REINSERT; skb_tc_reinsert(skb, res);
return TC_ACT_CONSUMED;
} }
} }