net/sched: store the last executed chain also for clsact egress

currently, only 'ingress' and 'clsact ingress' qdiscs store the tc 'chain
id' in the skb extension. However, userspace programs (like ovs) are able
to setup egress rules, and datapath gets confused in case it doesn't find
the 'chain id' for a packet that's "recirculated" by tc.
Change tcf_classify() to have the same semantic as tcf_classify_ingress()
so that a single function can be called in ingress / egress, using the tc
ingress / egress block respectively.

Suggested-by: Alaa Hleilel <alaa@nvidia.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 25 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 1167cd0be179..7be5b9d2aead 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1577,21 +1577,11 @@ reset:
 #endif
 }
 
-int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+int tcf_classify(struct sk_buff *skb,
+		 const struct tcf_block *block,
+		 const struct tcf_proto *tp,
 		 struct tcf_result *res, bool compat_mode)
 {
-	u32 last_executed_chain = 0;
-
-	return __tcf_classify(skb, tp, tp, res, compat_mode,
-			      &last_executed_chain);
-}
-EXPORT_SYMBOL(tcf_classify);
-
-int tcf_classify_ingress(struct sk_buff *skb,
-			 const struct tcf_block *ingress_block,
-			 const struct tcf_proto *tp,
-			 struct tcf_result *res, bool compat_mode)
-{
 #if !IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
 	u32 last_executed_chain = 0;
 
@@ -1603,20 +1593,22 @@ int tcf_classify_ingress(struct sk_buff *skb,
 	struct tc_skb_ext *ext;
 	int ret;
 
-	ext = skb_ext_find(skb, TC_SKB_EXT);
+	if (block) {
+		ext = skb_ext_find(skb, TC_SKB_EXT);
 
-	if (ext && ext->chain) {
-		struct tcf_chain *fchain;
+		if (ext && ext->chain) {
+			struct tcf_chain *fchain;
 
-		fchain = tcf_chain_lookup_rcu(ingress_block, ext->chain);
-		if (!fchain)
-			return TC_ACT_SHOT;
+			fchain = tcf_chain_lookup_rcu(block, ext->chain);
+			if (!fchain)
+				return TC_ACT_SHOT;
 
-		/* Consume, so cloned/redirect skbs won't inherit ext */
-		skb_ext_del(skb, TC_SKB_EXT);
+			/* Consume, so cloned/redirect skbs won't inherit ext */
+			skb_ext_del(skb, TC_SKB_EXT);
 
-		tp = rcu_dereference_bh(fchain->filter_chain);
-		last_executed_chain = fchain->index;
+			tp = rcu_dereference_bh(fchain->filter_chain);
+			last_executed_chain = fchain->index;
+		}
 	}
 
 	ret = __tcf_classify(skb, tp, orig_tp, res, compat_mode,
@@ -1635,7 +1627,7 @@ int tcf_classify_ingress(struct sk_buff *skb,
 	return ret;
 #endif
 }
-EXPORT_SYMBOL(tcf_classify_ingress);
+EXPORT_SYMBOL(tcf_classify);
 
 struct tcf_chain_info {
 	struct tcf_proto __rcu **pprev;
@@ -3825,7 +3817,7 @@ struct sk_buff *tcf_qevent_handle(struct tcf_qevent *qe, struct Qdisc *sch, stru
 
 	fl = rcu_dereference_bh(qe->filter_chain);
 
-	switch (tcf_classify(skb, fl, &cl_res, false)) {
+	switch (tcf_classify(skb, NULL, fl, &cl_res, false)) {
 	case TC_ACT_SHOT:
 		qdisc_qstats_drop(sch);
 		__qdisc_drop(skb, to_free);