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)
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
Note: this patch still touch only overlimits, even there is some
agreement to touch (also) drops on reinsert/mirred failure, but
such change is independent to this series
---
include/net/pkt_cls.h | 3 +++
include/net/sch_generic.h | 19 +++++++++++++++++++
net/core/dev.c | 6 +++++-
3 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index a3101582f642..d64915273358 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -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 {
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index c9af9ce33055..70270d9c1bb1 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -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;
+ };
};
};
@@ -1107,4 +1113,17 @@ 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
diff --git a/net/core/dev.c b/net/core/dev.c
index 87c42c8249ae..d5faa6449fb2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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->tc_redirected)
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;
}
--
2.17.1
