openvswitch: Add support for OVS_FLOW_ATTR_PROBE.

This new flag is useful for suppressing error logging while probing
for datapath features using flow commands.  For backwards
compatibility reasons the commands are executed normally, but error
logging is suppressed.

Signed-off-by: Jarno Rajahalme <[email protected]>
Signed-off-by: Pravin B Shelar <[email protected]>

Author: Jarno Rajahalme

include/uapi/linux/openvswitch.h

@@ -457,6 +457,8 @@ enum ovs_flow_attr {
 	OVS_FLOW_ATTR_USED,      /* u64 msecs last used in monotonic time. */
 	OVS_FLOW_ATTR_CLEAR,     /* Flag to clear stats, tcp_flags, used. */
 	OVS_FLOW_ATTR_MASK,      /* Sequence of OVS_KEY_ATTR_* attributes. */
+	OVS_FLOW_ATTR_PROBE,     /* Flow operation is a feature probe, error
+				  * logging should be suppressed. */
 	__OVS_FLOW_ATTR_MAX
 };
 

net/openvswitch/datapath.c

@@ -526,6 +526,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
 	struct vport *input_vport;
 	int len;
 	int err;
+	bool log = !a[OVS_FLOW_ATTR_PROBE];
 
 	err = -EINVAL;
 	if (!a[OVS_PACKET_ATTR_PACKET] || !a[OVS_PACKET_ATTR_KEY] ||
@@ -559,12 +560,12 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
 		goto err_kfree_skb;
 
 	err = ovs_flow_key_extract_userspace(a[OVS_PACKET_ATTR_KEY], packet,
-					     &flow->key);
+					     &flow->key, log);
 	if (err)
 		goto err_flow_free;
 
 	err = ovs_nla_copy_actions(a[OVS_PACKET_ATTR_ACTIONS],
-				   &flow->key, &acts);
+				   &flow->key, &acts, log);
 	if (err)
 		goto err_flow_free;
 
@@ -855,15 +856,16 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	struct sw_flow_actions *acts;
 	struct sw_flow_match match;
 	int error;
+	bool log = !a[OVS_FLOW_ATTR_PROBE];
 
 	/* Must have key and actions. */
 	error = -EINVAL;
 	if (!a[OVS_FLOW_ATTR_KEY]) {
-		OVS_NLERR("Flow key attribute not present in new flow.\n");
+		OVS_NLERR(log, "Flow key attr not present in new flow.");
 		goto error;
 	}
 	if (!a[OVS_FLOW_ATTR_ACTIONS]) {
-		OVS_NLERR("Flow actions attribute not present in new flow.\n");
+		OVS_NLERR(log, "Flow actions attr not present in new flow.");
 		goto error;
 	}
 
@@ -878,18 +880,18 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
 
 	/* Extract key. */
 	ovs_match_init(&match, &new_flow->unmasked_key, &mask);
-	error = ovs_nla_get_match(&match,
-				  a[OVS_FLOW_ATTR_KEY], a[OVS_FLOW_ATTR_MASK]);
+	error = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY],
+				  a[OVS_FLOW_ATTR_MASK], log);
 	if (error)
 		goto err_kfree_flow;
 
 	ovs_flow_mask_key(&new_flow->key, &new_flow->unmasked_key, &mask);
 
 	/* Validate actions. */
 	error = ovs_nla_copy_actions(a[OVS_FLOW_ATTR_ACTIONS], &new_flow->key,
-				     &acts);
+				     &acts, log);
 	if (error) {
-		OVS_NLERR("Flow actions may not be safe on all matching packets.\n");
+		OVS_NLERR(log, "Flow actions may not be safe on all matching packets.");
 		goto err_kfree_flow;
 	}
 
@@ -942,6 +944,7 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
 		}
 		/* The unmasked key has to be the same for flow updates. */
 		if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
+			/* Look for any overlapping flow. */
 			flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
 			if (!flow) {
 				error = -ENOENT;
@@ -984,16 +987,18 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
 /* Factor out action copy to avoid "Wframe-larger-than=1024" warning. */
 static struct sw_flow_actions *get_flow_actions(const struct nlattr *a,
 						const struct sw_flow_key *key,
-						const struct sw_flow_mask *mask)
+						const struct sw_flow_mask *mask,
+						bool log)
 {
 	struct sw_flow_actions *acts;
 	struct sw_flow_key masked_key;
 	int error;
 
 	ovs_flow_mask_key(&masked_key, key, mask);
-	error = ovs_nla_copy_actions(a, &masked_key, &acts);
+	error = ovs_nla_copy_actions(a, &masked_key, &acts, log);
 	if (error) {
-		OVS_NLERR("Actions may not be safe on all matching packets.\n");
+		OVS_NLERR(log,
+			  "Actions may not be safe on all matching packets");
 		return ERR_PTR(error);
 	}
 
@@ -1012,23 +1017,25 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	struct sw_flow_actions *old_acts = NULL, *acts = NULL;
 	struct sw_flow_match match;
 	int error;
+	bool log = !a[OVS_FLOW_ATTR_PROBE];
 
 	/* Extract key. */
 	error = -EINVAL;
 	if (!a[OVS_FLOW_ATTR_KEY]) {
-		OVS_NLERR("Flow key attribute not present in set flow.\n");
+		OVS_NLERR(log, "Flow key attribute not present in set flow.");
 		goto error;
 	}
 
 	ovs_match_init(&match, &key, &mask);
-	error = ovs_nla_get_match(&match,
-				  a[OVS_FLOW_ATTR_KEY], a[OVS_FLOW_ATTR_MASK]);
+	error = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY],
+				  a[OVS_FLOW_ATTR_MASK], log);
 	if (error)
 		goto error;
 
 	/* Validate actions. */
 	if (a[OVS_FLOW_ATTR_ACTIONS]) {
-		acts = get_flow_actions(a[OVS_FLOW_ATTR_ACTIONS], &key, &mask);
+		acts = get_flow_actions(a[OVS_FLOW_ATTR_ACTIONS], &key, &mask,
+					log);
 		if (IS_ERR(acts)) {
 			error = PTR_ERR(acts);
 			goto error;
@@ -1109,14 +1116,16 @@ static int ovs_flow_cmd_get(struct sk_buff *skb, struct genl_info *info)
 	struct datapath *dp;
 	struct sw_flow_match match;
 	int err;
+	bool log = !a[OVS_FLOW_ATTR_PROBE];
 
 	if (!a[OVS_FLOW_ATTR_KEY]) {
-		OVS_NLERR("Flow get message rejected, Key attribute missing.\n");
+		OVS_NLERR(log,
+			  "Flow get message rejected, Key attribute missing.");
 		return -EINVAL;
 	}
 
 	ovs_match_init(&match, &key, NULL);
-	err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL);
+	err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL, log);
 	if (err)
 		return err;
 
@@ -1157,10 +1166,12 @@ static int ovs_flow_cmd_del(struct sk_buff *skb, struct genl_info *info)
 	struct datapath *dp;
 	struct sw_flow_match match;
 	int err;
+	bool log = !a[OVS_FLOW_ATTR_PROBE];
 
 	if (likely(a[OVS_FLOW_ATTR_KEY])) {
 		ovs_match_init(&match, &key, NULL);
-		err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL);
+		err = ovs_nla_get_match(&match, a[OVS_FLOW_ATTR_KEY], NULL,
+					log);
 		if (unlikely(err))
 			return err;
 	}
@@ -1250,8 +1261,10 @@ static int ovs_flow_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 static const struct nla_policy flow_policy[OVS_FLOW_ATTR_MAX + 1] = {
 	[OVS_FLOW_ATTR_KEY] = { .type = NLA_NESTED },
+	[OVS_FLOW_ATTR_MASK] = { .type = NLA_NESTED },
 	[OVS_FLOW_ATTR_ACTIONS] = { .type = NLA_NESTED },
 	[OVS_FLOW_ATTR_CLEAR] = { .type = NLA_FLAG },
+	[OVS_FLOW_ATTR_PROBE] = { .type = NLA_FLAG },
 };
 
 static const struct genl_ops dp_flow_genl_ops[] = {

net/openvswitch/datapath.h

@@ -199,9 +199,9 @@ void ovs_dp_notify_wq(struct work_struct *work);
 int action_fifos_init(void);
 void action_fifos_exit(void);
 
-#define OVS_NLERR(fmt, ...)					\
+#define OVS_NLERR(logging_allowed, fmt, ...)			\
 do {								\
-	if (net_ratelimit())					\
-		pr_info("netlink: " fmt, ##__VA_ARGS__);	\
+	if (logging_allowed && net_ratelimit())			\
+		pr_info("netlink: " fmt "\n", ##__VA_ARGS__);	\
 } while (0)
 #endif /* datapath.h */

net/openvswitch/flow.c

@@ -712,12 +712,12 @@ int ovs_flow_key_extract(const struct ovs_tunnel_info *tun_info,
 
 int ovs_flow_key_extract_userspace(const struct nlattr *attr,
 				   struct sk_buff *skb,
-				   struct sw_flow_key *key)
+				   struct sw_flow_key *key, bool log)
 {
 	int err;
 
 	/* Extract metadata from netlink attributes. */
-	err = ovs_nla_get_flow_metadata(attr, key);
+	err = ovs_nla_get_flow_metadata(attr, key, log);
 	if (err)
 		return err;
 

net/openvswitch/flow.h

@@ -257,6 +257,6 @@ int ovs_flow_key_extract(const struct ovs_tunnel_info *tun_info,
 /* Extract key from packet coming from userspace. */
 int ovs_flow_key_extract_userspace(const struct nlattr *attr,
 				   struct sk_buff *skb,
-				   struct sw_flow_key *key);
+				   struct sw_flow_key *key, bool log);
 
 #endif /* flow.h */