net: openvswitch: Set OvS recirc_id from tc chain index

Offloaded OvS datapath rules are translated one to one to tc rules,
for example the following simplified OvS rule:

recirc_id(0),in_port(dev1),eth_type(0x0800),ct_state(-trk) actions:ct(),recirc(2)

Will be translated to the following tc rule:

$ tc filter add dev dev1 ingress \
	    prio 1 chain 0 proto ip \
		flower tcp ct_state -trk \
		action ct pipe \
		action goto chain 2

Received packets will first travel though tc, and if they aren't stolen
by it, like in the above rule, they will continue to OvS datapath.
Since we already did some actions (action ct in this case) which might
modify the packets, and updated action stats, we would like to continue
the proccessing with the correct recirc_id in OvS (here recirc_id(2))
where we left off.

To support this, introduce a new skb extension for tc, which
will be used for translating tc chain to ovs recirc_id to
handle these miss cases. Last tc chain index will be set
by tc goto chain action and read by OvS datapath.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 671ca905dbb5..05c4fe1c3ca2 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1514,6 +1514,18 @@ reclassify:
 			goto reset;
 		} else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
 			first_tp = res->goto_tp;
+
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+			{
+				struct tc_skb_ext *ext;
+
+				ext = skb_ext_add(skb, TC_SKB_EXT);
+				if (WARN_ON_ONCE(!ext))
+					return TC_ACT_SHOT;
+
+				ext->chain = err & TC_ACT_EXT_VAL_MASK;
+			}
+#endif
 			goto reset;
 		}
 #endif