datapath: Set OvS recirc_id from tc chain index

Upstream commit:
    commit 95a7233c452a58a4c2310c456c73997853b2ec46
    Author: Paul Blakey <paulb@mellanox.com>
    Date:   Wed Sep 4 16:56:37 2019 +0300

    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>

Backport the local datapath changes from this patch and add compat
layer fixup for the DECLARE_STATIC_KEY_FALSE macro.

Acked-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

4 files changed, 55 insertions, 5 deletions

diff --git a/datapath/datapath.c b/datapath/datapath.c
index c8c21d774..009887691 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1635,10 +1635,34 @@ static void ovs_dp_reset_user_features(struct sk_buff *skb, struct genl_info *in
 	dp->user_features = 0;
 }
 
-static void ovs_dp_change(struct datapath *dp, struct nlattr *a[])
+DEFINE_STATIC_KEY_FALSE(tc_recirc_sharing_support);
+
+static int ovs_dp_change(struct datapath *dp, struct nlattr *a[])
 {
-	if (a[OVS_DP_ATTR_USER_FEATURES])
-		dp->user_features = nla_get_u32(a[OVS_DP_ATTR_USER_FEATURES]);
+	u32 user_features = 0;
+
+	if (a[OVS_DP_ATTR_USER_FEATURES]) {
+		user_features = nla_get_u32(a[OVS_DP_ATTR_USER_FEATURES]);
+
+		if (user_features & ~(OVS_DP_F_VPORT_PIDS |
+				      OVS_DP_F_UNALIGNED |
+				      OVS_DP_F_TC_RECIRC_SHARING))
+			return -EOPNOTSUPP;
+
+#if !IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+		if (user_features & OVS_DP_F_TC_RECIRC_SHARING)
+			return -EOPNOTSUPP;
+#endif
+	}
+
+	dp->user_features = user_features;
+
+	if (dp->user_features & OVS_DP_F_TC_RECIRC_SHARING)
+		static_branch_enable(&tc_recirc_sharing_support);
+	else
+		static_branch_disable(&tc_recirc_sharing_support);
+
+	return 0;
 }
 
 static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
@@ -1700,7 +1724,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	parms.port_no = OVSP_LOCAL;
 	parms.upcall_portids = a[OVS_DP_ATTR_UPCALL_PID];
 
-	ovs_dp_change(dp, a);
+	err = ovs_dp_change(dp, a);
+	if (err)
+		goto err_destroy_meters;
 
 	/* So far only local changes have been made, now need the lock. */
 	ovs_lock();
@@ -1825,7 +1851,9 @@ static int ovs_dp_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	if (IS_ERR(dp))
 		goto err_unlock_free;
 
-	ovs_dp_change(dp, info->attrs);
+	err = ovs_dp_change(dp, info->attrs);
+	if (err)
+		goto err_unlock_free;
 
 	err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
 				   info->snd_seq, 0, OVS_DP_CMD_GET);
diff --git a/datapath/datapath.h b/datapath/datapath.h
index f99db1fde..c377e9b24 100644
--- a/datapath/datapath.h
+++ b/datapath/datapath.h
@@ -251,6 +251,8 @@ extern struct notifier_block ovs_dp_device_notifier;
 extern struct genl_family dp_vport_genl_family;
 extern const struct genl_multicast_group ovs_dp_vport_multicast_group;
 
+DECLARE_STATIC_KEY_FALSE(tc_recirc_sharing_support);
+
 void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key);
 void ovs_dp_detach_port(struct vport *);
 int ovs_dp_upcall(struct datapath *, struct sk_buff *,
diff --git a/datapath/flow.c b/datapath/flow.c
index 6dc7402d5..5a00c238c 100644
--- a/datapath/flow.c
+++ b/datapath/flow.c
@@ -874,6 +874,9 @@ static int key_extract_mac_proto(struct sk_buff *skb)
 int ovs_flow_key_extract(const struct ip_tunnel_info *tun_info,
 			 struct sk_buff *skb, struct sw_flow_key *key)
 {
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+	struct tc_skb_ext *tc_ext;
+#endif
 	int res, err;
 
 	/* Extract metadata from packet. */
@@ -904,7 +907,17 @@ int ovs_flow_key_extract(const struct ip_tunnel_info *tun_info,
 	if (res < 0)
 		return res;
 	key->mac_proto = res;
+
+#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
+	if (static_branch_unlikely(&tc_recirc_sharing_support)) {
+		tc_ext = skb_ext_find(skb, TC_SKB_EXT);
+		key->recirc_id = tc_ext ? tc_ext->chain : 0;
+	} else {
+		key->recirc_id = 0;
+	}
+#else
 	key->recirc_id = 0;
+#endif
 
 	err = key_extract(skb, key);
 	if (!err)
diff --git a/datapath/linux/compat/include/linux/static_key.h b/datapath/linux/compat/include/linux/static_key.h
index 7e43a49e8..432feccb9 100644
--- a/datapath/linux/compat/include/linux/static_key.h
+++ b/datapath/linux/compat/include/linux/static_key.h
@@ -74,6 +74,13 @@ static inline void rpl_static_key_disable(struct static_key *key)
 #define static_branch_enable(x)		rpl_static_key_enable(&(x)->key)
 #define static_branch_disable(x)	rpl_static_key_disable(&(x)->key)
 
+#ifndef HAVE_DECLARE_STATIC_KEY
+#define DECLARE_STATIC_KEY_TRUE(name)   \
+        extern struct static_key_true name
+#define DECLARE_STATIC_KEY_FALSE(name)  \
+        extern struct static_key_false name
+#endif
+
 #endif /* HAVE_UPSTREAM_STATIC_KEY */
 
 #endif /* _STATIC_KEY_WRAPPER_H */