Message-ID: <20240408125753.470419-6-amorenoz@redhat.com>
Date: Mon,  8 Apr 2024 14:57:44 +0200
From: Adrian Moreno <amorenoz@...hat.com>
To: netdev@...r.kernel.org
Cc: Adrian Moreno <amorenoz@...hat.com>,
	jiri@...nulli.us,
	xiyou.wangcong@...il.com,
	cmi@...dia.com,
	yotam.gi@...il.com,
	i.maximets@....org,
	aconole@...hat.com,
	echaudro@...hat.com,
	horms@...nel.org
Subject: [RFC net-next v2 5/5] net:openvswitch: add psample support

Add a new attribute to the sample action, called
OVS_SAMPLE_ATTR_PSAMPLE to allow userspace to pass a group_id and a
user-defined cookie.

The maximum length of the user-defined cookie is set to 16, same as
tc_cookie to discourage using cookies that will not be offloadable.

When set, the sample action will use psample to multicast the sample.

Signed-off-by: Adrian Moreno <amorenoz@...hat.com>
---
 include/uapi/linux/openvswitch.h | 22 +++++++--
 net/openvswitch/actions.c        | 52 ++++++++++++++++++---
 net/openvswitch/datapath.c       |  2 +-
 net/openvswitch/flow_netlink.c   | 78 +++++++++++++++++++++++++-------
 4 files changed, 127 insertions(+), 27 deletions(-)

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index efc82c318fa2..a5a32588f582 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -646,15 +646,24 @@ enum ovs_flow_attr {
  * %UINT32_MAX samples all packets and intermediate values sample intermediate
  * fractions of packets.
  * @OVS_SAMPLE_ATTR_ACTIONS: Set of actions to execute in sampling event.
- * Actions are passed as nested attributes.
+ * Actions are passed as nested attributes. Optional if OVS_SAMPLE_ATTR_PSAMPLE
+ * is not set.
+ * @OVS_SAMPLE_ATTR_PSAMPLE: Arguments to be passed to psample. Optional if
+ * OVS_SAMPLE_ATTR_ACTIONS is not set.
  *
- * Executes the specified actions with the given probability on a per-packet
- * basis.
+ * Either OVS_SAMPLE_ATTR_USER_COOKIE or OVS_SAMPLE_ATTR_USER_COOKIE must be
+ * specified.
+ *
+ * Executes the specified actions and/or sends the packet to psample
+ * with the given probability on a per-packet basis.
  */
 enum ovs_sample_attr {
 	OVS_SAMPLE_ATTR_UNSPEC,
 	OVS_SAMPLE_ATTR_PROBABILITY, /* u32 number */
 	OVS_SAMPLE_ATTR_ACTIONS,     /* Nested OVS_ACTION_ATTR_* attributes. */
+	OVS_SAMPLE_ATTR_PSAMPLE,     /* struct ovs_psample followed
+				      * by the user-provided cookie.
+				      */
 	__OVS_SAMPLE_ATTR_MAX,
 
 #ifdef __KERNEL__
@@ -675,6 +684,13 @@ struct sample_arg {
 };
 #endif
 
+#define OVS_PSAMPLE_COOKIE_MAX_SIZE 16
+struct ovs_psample {
+	__u32 group_id;		/* The group used for packet sampling. */
+	__u32 user_cookie_len;	/* The length of the user-provided cookie. */
+	__u8 user_cookie[];	/* The user-provided cookie. */
+};
+
 /**
  * enum ovs_userspace_attr - Attributes for %OVS_ACTION_ATTR_USERSPACE action.
  * @OVS_USERSPACE_ATTR_PID: u32 Netlink PID to which the %OVS_PACKET_CMD_ACTION
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 6fcd7e2ca81f..45d2b325b76a 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -24,6 +24,7 @@
 #include <net/checksum.h>
 #include <net/dsfield.h>
 #include <net/mpls.h>
+#include <net/psample.h>
 #include <net/sctp/checksum.h>
 
 #include "datapath.h"
@@ -1025,6 +1026,31 @@ static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
 	return 0;
 }
 
+static int ovs_psample_packet(struct datapath *dp, struct sw_flow_key *key,
+			      struct ovs_psample *psample, struct sk_buff *skb,
+			      u32 rate)
+{
+	struct psample_group psample_group = {};
+	struct psample_metadata md = {};
+	struct vport *input_vport;
+
+	psample_group.group_num = psample->group_id;
+	psample_group.net = ovs_dp_get_net(dp);
+
+	input_vport = ovs_vport_rcu(dp, key->phy.in_port);
+	if (!input_vport)
+		input_vport = ovs_vport_rcu(dp, OVSP_LOCAL);
+
+	md.in_ifindex = input_vport->dev->ifindex;
+	md.user_cookie = psample->user_cookie;
+	md.user_cookie_len = psample->user_cookie_len;
+	md.trunc_size = skb->len;
+
+	psample_sample_packet(&psample_group, skb, rate, &md);
+
+	return 0;
+}
+
 /* When 'last' is true, sample() should always consume the 'skb'.
  * Otherwise, sample() should keep 'skb' intact regardless what
  * actions are executed within sample().
@@ -1033,16 +1059,17 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
 		  struct sw_flow_key *key, const struct nlattr *attr,
 		  bool last)
 {
-	struct nlattr *actions;
+	const struct sample_arg *arg;
 	struct nlattr *sample_arg;
 	int rem = nla_len(attr);
-	const struct sample_arg *arg;
+	struct nlattr *next;
 	bool clone_flow_key;
+	int ret;
 
 	/* The first action is always 'OVS_SAMPLE_ATTR_ARG'. */
 	sample_arg = nla_data(attr);
 	arg = nla_data(sample_arg);
-	actions = nla_next(sample_arg, &rem);
+	next = nla_next(sample_arg, &rem);
 
 	if ((arg->probability != U32_MAX) &&
 	    (!arg->probability || get_random_u32() > arg->probability)) {
@@ -1051,9 +1078,22 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
 		return 0;
 	}
 
-	clone_flow_key = !arg->exec;
-	return clone_execute(dp, skb, key, 0, actions, rem, last,
-			     clone_flow_key);
+	if (next->nla_type == OVS_SAMPLE_ATTR_PSAMPLE) {
+		ret = ovs_psample_packet(dp, key, nla_data(next), skb,
+					 arg->probability);
+		if (last)
+			ovs_kfree_skb_reason(skb, OVS_DROP_LAST_ACTION);
+		if (ret)
+			return ret;
+		next = nla_next(next, &rem);
+	}
+
+	if (nla_ok(next, rem)) {
+		clone_flow_key = !arg->exec;
+		ret = clone_execute(dp, skb, key, 0, next, rem, last,
+				    clone_flow_key);
+	}
+	return ret;
 }
 
 /* When 'last' is true, clone() should always consume the 'skb'.
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 99d72543abd3..b5b560c2e74b 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -976,7 +976,7 @@ static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	struct sw_flow_match match;
 	u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
 	int error;
-	bool log = !a[OVS_FLOW_ATTR_PROBE];
+	bool log = true;
 
 	/* Must have key and actions. */
 	error = -EINVAL;
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index f224d9bcea5e..f540686271b7 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2381,8 +2381,12 @@ static void ovs_nla_free_sample_action(const struct nlattr *action)
 
 	switch (nla_type(a)) {
 	case OVS_SAMPLE_ATTR_ARG:
-		/* The real list of actions follows this attribute. */
 		a = nla_next(a, &rem);
+
+		/* OVS_SAMPLE_ATTR_PSAMPLE may be present. */
+		if (nla_type(a) == OVS_SAMPLE_ATTR_PSAMPLE)
+			a = nla_next(a, &rem);
+
 		ovs_nla_free_nested_actions(a, rem);
 		break;
 	}
@@ -2561,6 +2565,9 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
 				  u32 mpls_label_count, bool log,
 				  u32 depth);
 
+static int copy_action(const struct nlattr *from,
+		       struct sw_flow_actions **sfa, bool log);
+
 static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
 				    const struct sw_flow_key *key,
 				    struct sw_flow_actions **sfa,
@@ -2569,10 +2576,10 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
 				    u32 depth)
 {
 	const struct nlattr *attrs[OVS_SAMPLE_ATTR_MAX + 1];
-	const struct nlattr *probability, *actions;
+	const struct nlattr *probability, *actions, *psample;
 	const struct nlattr *a;
-	int rem, start, err;
 	struct sample_arg arg;
+	int rem, start, err;
 
 	memset(attrs, 0, sizeof(attrs));
 	nla_for_each_nested(a, attr, rem) {
@@ -2589,7 +2596,23 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
 		return -EINVAL;
 
 	actions = attrs[OVS_SAMPLE_ATTR_ACTIONS];
-	if (!actions || (nla_len(actions) && nla_len(actions) < NLA_HDRLEN))
+	if (actions && (!nla_len(actions) || nla_len(actions) < NLA_HDRLEN))
+		return -EINVAL;
+
+	psample = attrs[OVS_SAMPLE_ATTR_PSAMPLE];
+	if (psample) {
+		struct ovs_psample *ovs_ps;
+
+		if (!nla_len(psample) || nla_len(psample) < sizeof(*ovs_ps))
+			return -EINVAL;
+
+		ovs_ps = nla_data(psample);
+		if (ovs_ps->user_cookie_len > OVS_PSAMPLE_COOKIE_MAX_SIZE ||
+		    nla_len(psample) != sizeof(*ovs_ps) + ovs_ps->user_cookie_len)
+			return -EINVAL;
+	}
+
+	if (!psample && !actions)
 		return -EINVAL;
 
 	/* validation done, copy sample action. */
@@ -2608,7 +2631,9 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
 	 * If the sample is the last action, it can always be excuted
 	 * rather than deferred.
 	 */
-	arg.exec = last || !actions_may_change_flow(actions);
+	if (actions)
+		arg.exec = last || !actions_may_change_flow(actions);
+
 	arg.probability = nla_get_u32(probability);
 
 	err = ovs_nla_add_action(sfa, OVS_SAMPLE_ATTR_ARG, &arg, sizeof(arg),
@@ -2616,10 +2641,17 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
 	if (err)
 		return err;
 
-	err = __ovs_nla_copy_actions(net, actions, key, sfa,
-				     eth_type, vlan_tci, mpls_label_count, log,
-				     depth + 1);
+	if (psample)
+		err = ovs_nla_add_action(sfa, OVS_SAMPLE_ATTR_PSAMPLE,
+					 nla_data(psample), nla_len(psample),
+					 log);
+	if (err)
+		return err;
 
+	if (actions)
+		err = __ovs_nla_copy_actions(net, actions, key, sfa,
+					     eth_type, vlan_tci,
+					     mpls_label_count, log, depth + 1);
 	if (err)
 		return err;
 
@@ -3538,7 +3570,7 @@ static int sample_action_to_attr(const struct nlattr *attr,
 	struct nlattr *start, *ac_start = NULL, *sample_arg;
 	int err = 0, rem = nla_len(attr);
 	const struct sample_arg *arg;
-	struct nlattr *actions;
+	struct nlattr *next;
 
 	start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_SAMPLE);
 	if (!start)
@@ -3546,27 +3578,39 @@ static int sample_action_to_attr(const struct nlattr *attr,
 
 	sample_arg = nla_data(attr);
 	arg = nla_data(sample_arg);
-	actions = nla_next(sample_arg, &rem);
+	next = nla_next(sample_arg, &rem);
 
 	if (nla_put_u32(skb, OVS_SAMPLE_ATTR_PROBABILITY, arg->probability)) {
 		err = -EMSGSIZE;
 		goto out;
 	}
 
-	ac_start = nla_nest_start_noflag(skb, OVS_SAMPLE_ATTR_ACTIONS);
-	if (!ac_start) {
-		err = -EMSGSIZE;
-		goto out;
+	if (nla_type(next) == OVS_SAMPLE_ATTR_PSAMPLE) {
+		if (nla_put(skb, OVS_SAMPLE_ATTR_PSAMPLE, nla_len(next),
+			    nla_data(next))) {
+			err = -EMSGSIZE;
+			goto out;
+		}
+		next = nla_next(next, &rem);
 	}
 
-	err = ovs_nla_put_actions(actions, rem, skb);
+	if (nla_ok(next, rem)) {
+		ac_start = nla_nest_start_noflag(skb, OVS_SAMPLE_ATTR_ACTIONS);
+		if (!ac_start) {
+			err = -EMSGSIZE;
+			goto out;
+		}
+		err = ovs_nla_put_actions(next, rem, skb);
+	}
 
 out:
 	if (err) {
-		nla_nest_cancel(skb, ac_start);
+		if (ac_start)
+			nla_nest_cancel(skb, ac_start);
 		nla_nest_cancel(skb, start);
 	} else {
-		nla_nest_end(skb, ac_start);
+		if (ac_start)
+			nla_nest_end(skb, ac_start);
 		nla_nest_end(skb, start);
 	}
 
-- 
2.44.0

Powered by blists - more mailing lists