diff mbox series

[net-next,v7,06/10] net: openvswitch: store sampling probability in cb.

Message ID 20240630195740.1469727-7-amorenoz@redhat.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: openvswitch: Add sample multicasting. | expand

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netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; GEN HAS DIFF 2 files changed, 274 insertions(+), 164 deletions(-);
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 839 this patch: 839
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netdev/build_clang success Errors and warnings before: 846 this patch: 846
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netdev/verify_fixes success No Fixes tag
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netdev/kdoc success Errors and warnings before: 65 this patch: 65
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-07-01--21-00 (tests: 665)

Commit Message

Adrián Moreno June 30, 2024, 7:57 p.m. UTC 
When a packet sample is observed, the sampling rate that was used is
important to estimate the real frequency of such event.

Store the probability of the parent sample action in the skb's cb area
and use it in psample action to pass it down to psample module.

Acked-by: Eelco Chaudron <echaudro@redhat.com>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
---
 include/uapi/linux/openvswitch.h |  3 ++-
 net/openvswitch/actions.c        | 20 +++++++++++++++++---
 net/openvswitch/datapath.h       |  3 +++
 net/openvswitch/vport.c          |  1 +
 4 files changed, 23 insertions(+), 4 deletions(-)

Comments

Aaron Conole July 1, 2024, 6:24 p.m. UTC | #1 
Adrian Moreno <amorenoz@redhat.com> writes:

> When a packet sample is observed, the sampling rate that was used is
> important to estimate the real frequency of such event.
>
> Store the probability of the parent sample action in the skb's cb area
> and use it in psample action to pass it down to psample module.
>
> Acked-by: Eelco Chaudron <echaudro@redhat.com>
> Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
> Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
> ---

Reviewed-by: Aaron Conole <aconole@redhat.com>

>  include/uapi/linux/openvswitch.h |  3 ++-
>  net/openvswitch/actions.c        | 20 +++++++++++++++++---
>  net/openvswitch/datapath.h       |  3 +++
>  net/openvswitch/vport.c          |  1 +
>  4 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
> index 3dd653748725..3a701bd1f31b 100644
> --- a/include/uapi/linux/openvswitch.h
> +++ b/include/uapi/linux/openvswitch.h
> @@ -649,7 +649,8 @@ enum ovs_flow_attr {
>   * Actions are passed as nested attributes.
>   *
>   * Executes the specified actions with the given probability on a per-packet
> - * basis.
> + * basis. Nested actions will be able to access the probability value of the
> + * parent @OVS_ACTION_ATTR_SAMPLE.
>   */
>  enum ovs_sample_attr {
>  	OVS_SAMPLE_ATTR_UNSPEC,
> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
> index a035b7e677dd..34af6bce4085 100644
> --- a/net/openvswitch/actions.c
> +++ b/net/openvswitch/actions.c
> @@ -1048,12 +1048,15 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
>  	struct nlattr *sample_arg;
>  	int rem = nla_len(attr);
>  	const struct sample_arg *arg;
> +	u32 init_probability;
>  	bool clone_flow_key;
> +	int err;
>  
>  	/* 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);
> +	init_probability = OVS_CB(skb)->probability;
>  
>  	if ((arg->probability != U32_MAX) &&
>  	    (!arg->probability || get_random_u32() > arg->probability)) {
> @@ -1062,9 +1065,16 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
>  		return 0;
>  	}
>  
> +	OVS_CB(skb)->probability = arg->probability;
> +
>  	clone_flow_key = !arg->exec;
> -	return clone_execute(dp, skb, key, 0, actions, rem, last,
> -			     clone_flow_key);
> +	err = clone_execute(dp, skb, key, 0, actions, rem, last,
> +			    clone_flow_key);
> +
> +	if (!last)
> +		OVS_CB(skb)->probability = init_probability;
> +
> +	return err;
>  }
>  
>  /* When 'last' is true, clone() should always consume the 'skb'.
> @@ -1311,6 +1321,7 @@ static void execute_psample(struct datapath *dp, struct sk_buff *skb,
>  	struct psample_group psample_group = {};
>  	struct psample_metadata md = {};
>  	const struct nlattr *a;
> +	u32 rate;
>  	int rem;
>  
>  	nla_for_each_attr(a, nla_data(attr), nla_len(attr), rem) {
> @@ -1329,8 +1340,11 @@ static void execute_psample(struct datapath *dp, struct sk_buff *skb,
>  	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;
> +	md.rate_as_probability = 1;
> +
> +	rate = OVS_CB(skb)->probability ? OVS_CB(skb)->probability : U32_MAX;
>  
> -	psample_sample_packet(&psample_group, skb, 0, &md);
> +	psample_sample_packet(&psample_group, skb, rate, &md);
>  }
>  #else
>  static inline void execute_psample(struct datapath *dp, struct sk_buff *skb,
> diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
> index 0cd29971a907..9ca6231ea647 100644
> --- a/net/openvswitch/datapath.h
> +++ b/net/openvswitch/datapath.h
> @@ -115,12 +115,15 @@ struct datapath {
>   * fragmented.
>   * @acts_origlen: The netlink size of the flow actions applied to this skb.
>   * @cutlen: The number of bytes from the packet end to be removed.
> + * @probability: The sampling probability that was applied to this skb; 0 means
> + * no sampling has occurred; U32_MAX means 100% probability.
>   */
>  struct ovs_skb_cb {
>  	struct vport		*input_vport;
>  	u16			mru;
>  	u16			acts_origlen;
>  	u32			cutlen;
> +	u32			probability;
>  };
>  #define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)
>  
> diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
> index 972ae01a70f7..8732f6e51ae5 100644
> --- a/net/openvswitch/vport.c
> +++ b/net/openvswitch/vport.c
> @@ -500,6 +500,7 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
>  	OVS_CB(skb)->input_vport = vport;
>  	OVS_CB(skb)->mru = 0;
>  	OVS_CB(skb)->cutlen = 0;
> +	OVS_CB(skb)->probability = 0;
>  	if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
>  		u32 mark;
diff mbox series

Patch

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 3dd653748725..3a701bd1f31b 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -649,7 +649,8 @@  enum ovs_flow_attr {
  * Actions are passed as nested attributes.
  *
  * Executes the specified actions with the given probability on a per-packet
- * basis.
+ * basis. Nested actions will be able to access the probability value of the
+ * parent @OVS_ACTION_ATTR_SAMPLE.
  */
 enum ovs_sample_attr {
 	OVS_SAMPLE_ATTR_UNSPEC,
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index a035b7e677dd..34af6bce4085 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1048,12 +1048,15 @@  static int sample(struct datapath *dp, struct sk_buff *skb,
 	struct nlattr *sample_arg;
 	int rem = nla_len(attr);
 	const struct sample_arg *arg;
+	u32 init_probability;
 	bool clone_flow_key;
+	int err;
 
 	/* 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);
+	init_probability = OVS_CB(skb)->probability;
 
 	if ((arg->probability != U32_MAX) &&
 	    (!arg->probability || get_random_u32() > arg->probability)) {
@@ -1062,9 +1065,16 @@  static int sample(struct datapath *dp, struct sk_buff *skb,
 		return 0;
 	}
 
+	OVS_CB(skb)->probability = arg->probability;
+
 	clone_flow_key = !arg->exec;
-	return clone_execute(dp, skb, key, 0, actions, rem, last,
-			     clone_flow_key);
+	err = clone_execute(dp, skb, key, 0, actions, rem, last,
+			    clone_flow_key);
+
+	if (!last)
+		OVS_CB(skb)->probability = init_probability;
+
+	return err;
 }
 
 /* When 'last' is true, clone() should always consume the 'skb'.
@@ -1311,6 +1321,7 @@  static void execute_psample(struct datapath *dp, struct sk_buff *skb,
 	struct psample_group psample_group = {};
 	struct psample_metadata md = {};
 	const struct nlattr *a;
+	u32 rate;
 	int rem;
 
 	nla_for_each_attr(a, nla_data(attr), nla_len(attr), rem) {
@@ -1329,8 +1340,11 @@  static void execute_psample(struct datapath *dp, struct sk_buff *skb,
 	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;
+	md.rate_as_probability = 1;
+
+	rate = OVS_CB(skb)->probability ? OVS_CB(skb)->probability : U32_MAX;
 
-	psample_sample_packet(&psample_group, skb, 0, &md);
+	psample_sample_packet(&psample_group, skb, rate, &md);
 }
 #else
 static inline void execute_psample(struct datapath *dp, struct sk_buff *skb,
diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
index 0cd29971a907..9ca6231ea647 100644
--- a/net/openvswitch/datapath.h
+++ b/net/openvswitch/datapath.h
@@ -115,12 +115,15 @@  struct datapath {
  * fragmented.
  * @acts_origlen: The netlink size of the flow actions applied to this skb.
  * @cutlen: The number of bytes from the packet end to be removed.
+ * @probability: The sampling probability that was applied to this skb; 0 means
+ * no sampling has occurred; U32_MAX means 100% probability.
  */
 struct ovs_skb_cb {
 	struct vport		*input_vport;
 	u16			mru;
 	u16			acts_origlen;
 	u32			cutlen;
+	u32			probability;
 };
 #define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)
 
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 972ae01a70f7..8732f6e51ae5 100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -500,6 +500,7 @@  int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
 	OVS_CB(skb)->input_vport = vport;
 	OVS_CB(skb)->mru = 0;
 	OVS_CB(skb)->cutlen = 0;
+	OVS_CB(skb)->probability = 0;
 	if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
 		u32 mark;