Commit aae0b82b authored by Adrian Moreno's avatar Adrian Moreno Committed by Jakub Kicinski
Browse files

net: openvswitch: add psample action 



Add support for a new action: psample.

This action accepts a u32 group id and a variable-length cookie and uses
the psample multicast group to make the packet available for
observability.

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.

Reviewed-by: default avatarMichal Kubiak <michal.kubiak@intel.com>
Reviewed-by: default avatarAaron Conole <aconole@redhat.com>
Reviewed-by: default avatarIlya Maximets <i.maximets@ovn.org>
Acked-by: default avatarEelco Chaudron <echaudro@redhat.com>
Signed-off-by: default avatarAdrian Moreno <amorenoz@redhat.com>
Link: https://patch.msgid.link/20240704085710.353845-6-amorenoz@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 7b1b2b60

Documentation/netlink/specs/ovs_flow.yaml

+17 −0
Original line number Diff line number Diff line
@@ -727,6 +727,12 @@ attribute-sets: 
        name: dec-ttl

        type: nest

        nested-attributes: dec-ttl-attrs

      -

        name: psample

        type: nest

        nested-attributes: psample-attrs

        doc: |

          Sends a packet sample to psample for external observation.

  -

    name: tunnel-key-attrs

    enum-name: ovs-tunnel-key-attr
@@ -938,6 +944,17 @@ attribute-sets: 
      -

        name: gbp

        type: u32

  -

    name: psample-attrs

    enum-name: ovs-psample-attr

    name-prefix: ovs-psample-attr-

    attributes:

      -

        name: group

        type: u32

      -

        name: cookie

        type: binary



operations:

  name-prefix: ovs-flow-cmd-

include/uapi/linux/openvswitch.h

+28 −0
Original line number Diff line number Diff line
@@ -914,6 +914,31 @@ struct check_pkt_len_arg { 
};

#endif



#define OVS_PSAMPLE_COOKIE_MAX_SIZE 16

/**

 * enum ovs_psample_attr - Attributes for %OVS_ACTION_ATTR_PSAMPLE

 * action.

 *

 * @OVS_PSAMPLE_ATTR_GROUP: 32-bit number to identify the source of the

 * sample.

 * @OVS_PSAMPLE_ATTR_COOKIE: An optional variable-length binary cookie that

 * contains user-defined metadata. The maximum length is

 * OVS_PSAMPLE_COOKIE_MAX_SIZE bytes.

 *

 * Sends the packet to the psample multicast group with the specified group and

 * cookie. It is possible to combine this action with the

 * %OVS_ACTION_ATTR_TRUNC action to limit the size of the sample.

 */

enum ovs_psample_attr {

	OVS_PSAMPLE_ATTR_GROUP = 1,	/* u32 number. */

	OVS_PSAMPLE_ATTR_COOKIE,	/* Optional, user specified cookie. */



	/* private: */

	__OVS_PSAMPLE_ATTR_MAX

};



#define OVS_PSAMPLE_ATTR_MAX (__OVS_PSAMPLE_ATTR_MAX - 1)



/**

 * enum ovs_action_attr - Action types.

 *
@@ -966,6 +991,8 @@ struct check_pkt_len_arg { 
 * of l3 tunnel flag in the tun_flags field of OVS_ACTION_ATTR_ADD_MPLS

 * argument.

 * @OVS_ACTION_ATTR_DROP: Explicit drop action.

 * @OVS_ACTION_ATTR_PSAMPLE: Send a sample of the packet to external observers

 * via psample.

 *

 * Only a single header can be set with a single %OVS_ACTION_ATTR_SET.  Not all

 * fields within a header are modifiable, e.g. the IPv4 protocol and fragment
@@ -1004,6 +1031,7 @@ enum ovs_action_attr { 
	OVS_ACTION_ATTR_ADD_MPLS,     /* struct ovs_action_add_mpls. */

	OVS_ACTION_ATTR_DEC_TTL,      /* Nested OVS_DEC_TTL_ATTR_*. */

	OVS_ACTION_ATTR_DROP,         /* u32 error code. */

	OVS_ACTION_ATTR_PSAMPLE,      /* Nested OVS_PSAMPLE_ATTR_*. */



	__OVS_ACTION_ATTR_MAX,	      /* Nothing past this will be accepted

				       * from userspace. */

net/openvswitch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ config OPENVSWITCH 
		   (NF_CONNTRACK && ((!NF_DEFRAG_IPV6 || NF_DEFRAG_IPV6) && \

				     (!NF_NAT || NF_NAT) && \

				     (!NETFILTER_CONNCOUNT || NETFILTER_CONNCOUNT)))

	depends on PSAMPLE || !PSAMPLE

	select LIBCRC32C

	select MPLS

	select NET_MPLS_GSO

net/openvswitch/actions.c

+48 −0
Original line number Diff line number Diff line
@@ -24,6 +24,11 @@ 
#include <net/checksum.h>

#include <net/dsfield.h>

#include <net/mpls.h>



#if IS_ENABLED(CONFIG_PSAMPLE)

#include <net/psample.h>

#endif



#include <net/sctp/checksum.h>



#include "datapath.h"
@@ -1299,6 +1304,40 @@ static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key) 
	return 0;

}



#if IS_ENABLED(CONFIG_PSAMPLE)

static void execute_psample(struct datapath *dp, struct sk_buff *skb,

			    const struct nlattr *attr)

{

	struct psample_group psample_group = {};

	struct psample_metadata md = {};

	const struct nlattr *a;

	int rem;



	nla_for_each_attr(a, nla_data(attr), nla_len(attr), rem) {

		switch (nla_type(a)) {

		case OVS_PSAMPLE_ATTR_GROUP:

			psample_group.group_num = nla_get_u32(a);

			break;



		case OVS_PSAMPLE_ATTR_COOKIE:

			md.user_cookie = nla_data(a);

			md.user_cookie_len = nla_len(a);

			break;

		}

	}



	psample_group.net = ovs_dp_get_net(dp);

	md.in_ifindex = OVS_CB(skb)->input_vport->dev->ifindex;

	md.trunc_size = skb->len - OVS_CB(skb)->cutlen;



	psample_sample_packet(&psample_group, skb, 0, &md);

}

#else

static void execute_psample(struct datapath *dp, struct sk_buff *skb,

			    const struct nlattr *attr)

{}

#endif



/* Execute a list of actions against 'skb'. */

static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,

			      struct sw_flow_key *key,
@@ -1502,6 +1541,15 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, 
			ovs_kfree_skb_reason(skb, reason);

			return 0;

		}



		case OVS_ACTION_ATTR_PSAMPLE:

			execute_psample(dp, skb, a);

			OVS_CB(skb)->cutlen = 0;

			if (nla_is_last(a, rem)) {

				consume_skb(skb);

				return 0;

			}

			break;

		}



		if (unlikely(err)) {

net/openvswitch/flow_netlink.c

+31 −1
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ static bool actions_may_change_flow(const struct nlattr *actions) 
		case OVS_ACTION_ATTR_TRUNC:

		case OVS_ACTION_ATTR_USERSPACE:

		case OVS_ACTION_ATTR_DROP:

		case OVS_ACTION_ATTR_PSAMPLE:

			break;



		case OVS_ACTION_ATTR_CT:
@@ -2409,7 +2410,7 @@ static void ovs_nla_free_nested_actions(const struct nlattr *actions, int len) 
	/* Whenever new actions are added, the need to update this

	 * function should be considered.

	 */

	BUILD_BUG_ON(OVS_ACTION_ATTR_MAX != 24);

	BUILD_BUG_ON(OVS_ACTION_ATTR_MAX != 25);



	if (!actions)

		return;
@@ -3157,6 +3158,28 @@ static int validate_and_copy_check_pkt_len(struct net *net, 
	return 0;

}



static int validate_psample(const struct nlattr *attr)

{

	static const struct nla_policy policy[OVS_PSAMPLE_ATTR_MAX + 1] = {

		[OVS_PSAMPLE_ATTR_GROUP] = { .type = NLA_U32 },

		[OVS_PSAMPLE_ATTR_COOKIE] = {

			.type = NLA_BINARY,

			.len = OVS_PSAMPLE_COOKIE_MAX_SIZE,

		},

	};

	struct nlattr *a[OVS_PSAMPLE_ATTR_MAX + 1];

	int err;



	if (!IS_ENABLED(CONFIG_PSAMPLE))

		return -EOPNOTSUPP;



	err = nla_parse_nested(a, OVS_PSAMPLE_ATTR_MAX, attr, policy, NULL);

	if (err)

		return err;



	return a[OVS_PSAMPLE_ATTR_GROUP] ? 0 : -EINVAL;

}



static int copy_action(const struct nlattr *from,

		       struct sw_flow_actions **sfa, bool log)

{
@@ -3212,6 +3235,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr, 
			[OVS_ACTION_ATTR_ADD_MPLS] = sizeof(struct ovs_action_add_mpls),

			[OVS_ACTION_ATTR_DEC_TTL] = (u32)-1,

			[OVS_ACTION_ATTR_DROP] = sizeof(u32),

			[OVS_ACTION_ATTR_PSAMPLE] = (u32)-1,

		};

		const struct ovs_action_push_vlan *vlan;

		int type = nla_type(a);
@@ -3490,6 +3514,12 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr, 
				return -EINVAL;

			break;



		case OVS_ACTION_ATTR_PSAMPLE:

			err = validate_psample(a);

			if (err)

				return err;

			break;



		default:

			OVS_NLERR(log, "Unknown Action type %d", type);

			return -EINVAL;