The behavior of actions might not be the exact same if they are being executed inside a nested sample action. Store the probability of the parent sample action in the skb's cb area.
Use the probability in emit_sample to pass it down to psample. Signed-off-by: Adrian Moreno <[email protected]> --- include/uapi/linux/openvswitch.h | 3 ++- net/openvswitch/actions.c | 25 ++++++++++++++++++++++--- net/openvswitch/datapath.h | 3 +++ net/openvswitch/vport.c | 1 + 4 files changed, 28 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index a0e9dde0584a..9d675725fa2b 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 3b4dba0ded59..33f6d93ba5e4 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 +1065,21 @@ static int sample(struct datapath *dp, struct sk_buff *skb, return 0; } + if (init_probability) { + OVS_CB(skb)->probability = ((u64)OVS_CB(skb)->probability * + arg->probability / U32_MAX); + } else { + 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'. @@ -1313,6 +1328,7 @@ static int execute_emit_sample(struct datapath *dp, struct sk_buff *skb, struct psample_metadata md = {}; struct vport *input_vport; const struct nlattr *a; + u32 rate; int rem; for (a = nla_data(attr), rem = nla_len(attr); rem > 0; @@ -1337,8 +1353,11 @@ static int execute_emit_sample(struct datapath *dp, struct sk_buff *skb, md.in_ifindex = 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); #endif return 0; 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; -- 2.45.1 _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
