[PATCH net-next v2 5/9] net: openvswitch: add emit_sample action
From: Adrian Moreno
Date: Mon Jun 03 2024 - 14:58:15 EST
Add support for a new action: emit_sample.
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.
Signed-off-by: Adrian Moreno <amorenoz@xxxxxxxxxx>
---
Documentation/netlink/specs/ovs_flow.yaml | 17 ++++++++
include/uapi/linux/openvswitch.h | 25 ++++++++++++
net/openvswitch/actions.c | 50 +++++++++++++++++++++++
net/openvswitch/flow_netlink.c | 33 ++++++++++++++-
4 files changed, 124 insertions(+), 1 deletion(-)
diff --git a/Documentation/netlink/specs/ovs_flow.yaml b/Documentation/netlink/specs/ovs_flow.yaml
index 4fdfc6b5cae9..a7ab5593a24f 100644
--- a/Documentation/netlink/specs/ovs_flow.yaml
+++ b/Documentation/netlink/specs/ovs_flow.yaml
@@ -727,6 +727,12 @@ attribute-sets:
name: dec-ttl
type: nest
nested-attributes: dec-ttl-attrs
+ -
+ name: emit-sample
+ type: nest
+ nested-attributes: emit-sample-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: emit-sample-attrs
+ enum-name: ovs-emit-sample-attr
+ name-prefix: ovs-emit-sample-attr-
+ attributes:
+ -
+ name: group
+ type: u32
+ -
+ name: cookie
+ type: binary
operations:
name-prefix: ovs-flow-cmd-
diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index efc82c318fa2..a0e9dde0584a 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -914,6 +914,30 @@ struct check_pkt_len_arg {
};
#endif
+#define OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE 16
+/**
+ * enum ovs_emit_sample_attr - Attributes for %OVS_ACTION_ATTR_EMIT_SAMPLE
+ * action.
+ *
+ * @OVS_EMIT_SAMPLE_ATTR_GROUP: 32-bit number to identify the source of the
+ * sample.
+ * @OVS_EMIT_SAMPLE_ATTR_COOKIE: A variable-length binary cookie that contains
+ * user-defined metadata. The maximum length is 16 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 packet being emitted.
+ */
+enum ovs_emit_sample_attr {
+ OVS_EMIT_SAMPLE_ATTR_UNPSEC,
+ OVS_EMIT_SAMPLE_ATTR_GROUP, /* u32 number. */
+ OVS_EMIT_SAMPLE_ATTR_COOKIE, /* Optional, user specified cookie. */
+ __OVS_EMIT_SAMPLE_ATTR_MAX
+};
+
+#define OVS_EMIT_SAMPLE_ATTR_MAX (__OVS_EMIT_SAMPLE_ATTR_MAX - 1)
+
+
/**
* enum ovs_action_attr - Action types.
*
@@ -1004,6 +1028,7 @@ 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_EMIT_SAMPLE, /* Nested OVS_EMIT_SAMPLE_ATTR_*. */
__OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
* from userspace. */
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 964225580824..3b4dba0ded59 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -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 +1304,46 @@ static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key)
return 0;
}
+static int execute_emit_sample(struct datapath *dp, struct sk_buff *skb,
+ const struct sw_flow_key *key,
+ const struct nlattr *attr)
+{
+#if IS_ENABLED(CONFIG_PSAMPLE)
+ struct psample_group psample_group = {};
+ struct psample_metadata md = {};
+ struct vport *input_vport;
+ const struct nlattr *a;
+ int rem;
+
+ for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
+ a = nla_next(a, &rem)) {
+ switch (nla_type(a)) {
+ case OVS_EMIT_SAMPLE_ATTR_GROUP:
+ psample_group.group_num = nla_get_u32(a);
+ break;
+
+ case OVS_EMIT_SAMPLE_ATTR_COOKIE:
+ md.user_cookie = nla_data(a);
+ md.user_cookie_len = nla_len(a);
+ break;
+ }
+ }
+
+ 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.trunc_size = skb->len - OVS_CB(skb)->cutlen;
+
+ psample_sample_packet(&psample_group, skb, 0, &md);
+#endif
+
+ return 0;
+}
+
/* 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 +1547,11 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
ovs_kfree_skb_reason(skb, reason);
return 0;
}
+
+ case OVS_ACTION_ATTR_EMIT_SAMPLE:
+ err = execute_emit_sample(dp, skb, key, a);
+ OVS_CB(skb)->cutlen = 0;
+ break;
}
if (unlikely(err)) {
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index f224d9bcea5e..eb59ff9c8154 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -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_EMIT_SAMPLE:
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 +3158,29 @@ static int validate_and_copy_check_pkt_len(struct net *net,
return 0;
}
+static int validate_emit_sample(const struct nlattr *attr)
+{
+ static const struct nla_policy policy[OVS_EMIT_SAMPLE_ATTR_MAX + 1] = {
+ [OVS_EMIT_SAMPLE_ATTR_GROUP] = { .type = NLA_U32 },
+ [OVS_EMIT_SAMPLE_ATTR_COOKIE] = {
+ .type = NLA_BINARY,
+ .len = OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE
+ },
+ };
+ struct nlattr *a[OVS_EMIT_SAMPLE_ATTR_MAX + 1];
+ int err;
+
+ if (!IS_ENABLED(CONFIG_PSAMPLE))
+ return -EOPNOTSUPP;
+
+ err = nla_parse_nested(a, OVS_EMIT_SAMPLE_ATTR_MAX, attr, policy,
+ NULL);
+ if (err)
+ return err;
+
+ return a[OVS_EMIT_SAMPLE_ATTR_GROUP] ? 0 : -EINVAL;
+}
+
static int copy_action(const struct nlattr *from,
struct sw_flow_actions **sfa, bool log)
{
@@ -3212,6 +3236,7 @@ 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_EMIT_SAMPLE] = (u32)-1,
};
const struct ovs_action_push_vlan *vlan;
int type = nla_type(a);
@@ -3490,6 +3515,12 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
return -EINVAL;
break;
+ case OVS_ACTION_ATTR_EMIT_SAMPLE:
+ err = validate_emit_sample(a);
+ if (err)
+ return err;
+ break;
+
default:
OVS_NLERR(log, "Unknown Action type %d", type);
return -EINVAL;
--
2.45.1