On 6/18/24 11:47, Ilya Maximets wrote: > On 6/18/24 09:33, Adrián Moreno wrote: >> On Mon, Jun 17, 2024 at 12:44:45PM GMT, Ilya Maximets wrote: >>> On 6/3/24 20:56, Adrian Moreno wrote: >>>> 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 <amore...@redhat.com> >>>> --- >>>> 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(-) >>> >>> Some nits below, beside ones already mentioned. >>> >> >> Thanks, Ilya. >> >>>> >>>> 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. >>> >>> s/16/OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE/ >>> >>>> + * >>>> + * 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)) { >>> >>> Since the action is strictly validated, can use use nla_for_each_attr() >>> or nla_for_each_nested() ? >>> >> >> Probably, yes. >> >>>> + 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); >>> >>> We may need to check that we actually found the local port. >>> >> >> Sure. What can cause the local port not to exist? > > I would assume that since we're only protected by RCU here, there can be > a race with datapath destruction that will remove the local port.
But, actually, we don't even need to look anything up. The original input vport should be available in OVS_CB(skb)->input_vport. Best regards, Ilya Maximets. _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev