net/sched: cls_flower add CT_FLAGS_INVALID flag support

This patch add the TCA_FLOWER_KEY_CT_FLAGS_INVALID flag to
match the ct_state with invalid for conntrack.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/1611045110-682-1-git-send-email-wenxu@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/skbuff.h

@@ -1353,8 +1353,8 @@ void
 skb_flow_dissect_ct(const struct sk_buff *skb,
 		    struct flow_dissector *flow_dissector,
 		    void *target_container,
-		    u16 *ctinfo_map,
-		    size_t mapsize);
+		    u16 *ctinfo_map, size_t mapsize,
+		    bool post_ct);
 void
 skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
 			     struct flow_dissector *flow_dissector,

include/net/sch_generic.h

@@ -388,6 +388,7 @@ struct qdisc_skb_cb {
 #define QDISC_CB_PRIV_LEN 20
 	unsigned char		data[QDISC_CB_PRIV_LEN];
 	u16			mru;
+	bool			post_ct;
 };
 
 typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);

include/uapi/linux/pkt_cls.h

@@ -591,6 +591,7 @@ enum {
 	TCA_FLOWER_KEY_CT_FLAGS_ESTABLISHED = 1 << 1, /* Part of an existing connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_RELATED = 1 << 2, /* Related to an established connection. */
 	TCA_FLOWER_KEY_CT_FLAGS_TRACKED = 1 << 3, /* Conntrack has occurred. */
+	TCA_FLOWER_KEY_CT_FLAGS_INVALID = 1 << 4, /* Conntrack is invalid. */
 };
 
 enum {

net/core/dev.c

@@ -3878,6 +3878,7 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
 
 	/* qdisc_skb_cb(skb)->pkt_len was already set by the caller. */
 	qdisc_skb_cb(skb)->mru = 0;
+	qdisc_skb_cb(skb)->post_ct = false;
 	mini_qdisc_bstats_cpu_update(miniq, skb);
 
 	switch (tcf_classify(skb, miniq->filter_list, &cl_res, false)) {
@@ -4960,6 +4961,7 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
 
 	qdisc_skb_cb(skb)->pkt_len = skb->len;
 	qdisc_skb_cb(skb)->mru = 0;
+	qdisc_skb_cb(skb)->post_ct = false;
 	skb->tc_at_ingress = 1;
 	mini_qdisc_bstats_cpu_update(miniq, skb);
 

net/core/flow_dissector.c

@@ -237,9 +237,8 @@ skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type,
 void
 skb_flow_dissect_ct(const struct sk_buff *skb,
 		    struct flow_dissector *flow_dissector,
-		    void *target_container,
-		    u16 *ctinfo_map,
-		    size_t mapsize)
+		    void *target_container, u16 *ctinfo_map,
+		    size_t mapsize, bool post_ct)
 {
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	struct flow_dissector_key_ct *key;
@@ -251,13 +250,19 @@ skb_flow_dissect_ct(const struct sk_buff *skb,
 		return;
 
 	ct = nf_ct_get(skb, &ctinfo);
-	if (!ct)
+	if (!ct && !post_ct)
 		return;
 
 	key = skb_flow_dissector_target(flow_dissector,
 					FLOW_DISSECTOR_KEY_CT,
 					target_container);
 
+	if (!ct) {
+		key->ct_state = TCA_FLOWER_KEY_CT_FLAGS_TRACKED |
+				TCA_FLOWER_KEY_CT_FLAGS_INVALID;
+		return;
+	}
+
 	if (ctinfo < mapsize)
 		key->ct_state = ctinfo_map[ctinfo];
 #if IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES)

net/sched/act_ct.c

@@ -1030,6 +1030,7 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
 
 out:
 	tcf_action_update_bstats(&c->common, skb);
+	qdisc_skb_cb(skb)->post_ct = true;
 	if (defrag)
 		qdisc_skb_cb(skb)->pkt_len = skb->len;
 	return retval;

net/sched/cls_flower.c

@@ -302,6 +302,7 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 		       struct tcf_result *res)
 {
 	struct cls_fl_head *head = rcu_dereference_bh(tp->root);
+	bool post_ct = qdisc_skb_cb(skb)->post_ct;
 	struct fl_flow_key skb_key;
 	struct fl_flow_mask *mask;
 	struct cls_fl_filter *f;
@@ -318,7 +319,8 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 		skb_flow_dissect_tunnel_info(skb, &mask->dissector, &skb_key);
 		skb_flow_dissect_ct(skb, &mask->dissector, &skb_key,
 				    fl_ct_info_to_flower_map,
-				    ARRAY_SIZE(fl_ct_info_to_flower_map));
+				    ARRAY_SIZE(fl_ct_info_to_flower_map),
+				    post_ct);
 		skb_flow_dissect_hash(skb, &mask->dissector, &skb_key);
 		skb_flow_dissect(skb, &mask->dissector, &skb_key, 0);