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 <[email protected]>
---
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
Hi Adrian,
kernel test robot noticed the following build errors:
[auto build test ERROR on net-next/main]
url: https://github.com/intel-lab-lkp/linux/commits/Adrian-Moreno/net-psample-add-user-cookie/20240604-030055
base: net-next/main
patch link: https://lore.kernel.org/r/20240603185647.2310748-6-amorenoz%40redhat.com
patch subject: [PATCH net-next v2 5/9] net: openvswitch: add emit_sample action
config: s390-randconfig-002-20240605 (https://download.01.org/0day-ci/archive/20240605/[email protected]/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d7d2d4f53fc79b4b58e8d8d08151b577c3699d4a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240605/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
s390x-linux-ld: net/openvswitch/actions.o: in function `do_execute_actions':
>> actions.c:(.text+0x1d5c): undefined reference to `psample_sample_packet'
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Wed, Jun 05, 2024 at 08:29:22AM GMT, kernel test robot wrote:
> Hi Adrian,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on net-next/main]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Adrian-Moreno/net-psample-add-user-cookie/20240604-030055
> base: net-next/main
> patch link: https://lore.kernel.org/r/20240603185647.2310748-6-amorenoz%40redhat.com
> patch subject: [PATCH net-next v2 5/9] net: openvswitch: add emit_sample action
> config: s390-randconfig-002-20240605 (https://download.01.org/0day-ci/archive/20240605/[email protected]/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d7d2d4f53fc79b4b58e8d8d08151b577c3699d4a)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240605/[email protected]/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <[email protected]>
> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
>
> All errors (new ones prefixed by >>):
>
> s390x-linux-ld: net/openvswitch/actions.o: in function `do_execute_actions':
> >> actions.c:(.text+0x1d5c): undefined reference to `psample_sample_packet'
>
Thanks robot!
OK, I think I know what's wrong. There is an optional dependency with
PSAMPLE. Openvswitch module does compile without PSAMPLE but there is a
link error if OPENVSWITCH=y and PSAMPLE=m.
Looking into how to express this in the Kconfig, I'm planning to add the
following to the next version of the series.
diff --git a/net/openvswitch/Kconfig b/net/openvswitch/Kconfig
index 29a7081858cd..2535f3f9f462 100644
--- a/net/openvswitch/Kconfig
+++ b/net/openvswitch/Kconfig
@@ -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
On Mon, Jun 03, 2024 at 08:56:39PM +0200, 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 <[email protected]>
Hi Adrian,
Some minor nits from my side.
...
> 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)
> +
> +
nit: One blank line is enough.
Flagged by checkpatch.pl
> /**
> * 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_*. */
nit: Please add OVS_ACTION_ATTR_EMIT_SAMPLE to the Kenrel doc
for this structure.
>
> __OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
> * from userspace. */
...
On Wed, Jun 05, 2024 at 07:31:55PM +0000, Adrián Moreno wrote:
> On Wed, Jun 05, 2024 at 08:29:22AM GMT, kernel test robot wrote:
> > Hi Adrian,
> >
> > kernel test robot noticed the following build errors:
> >
> > [auto build test ERROR on net-next/main]
> >
> > url: https://github.com/intel-lab-lkp/linux/commits/Adrian-Moreno/net-psample-add-user-cookie/20240604-030055
> > base: net-next/main
> > patch link: https://lore.kernel.org/r/20240603185647.2310748-6-amorenoz%40redhat.com
> > patch subject: [PATCH net-next v2 5/9] net: openvswitch: add emit_sample action
> > config: s390-randconfig-002-20240605 (https://download.01.org/0day-ci/archive/20240605/[email protected]/config)
> > compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project d7d2d4f53fc79b4b58e8d8d08151b577c3699d4a)
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240605/[email protected]/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <[email protected]>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> >
> > All errors (new ones prefixed by >>):
> >
> > s390x-linux-ld: net/openvswitch/actions.o: in function `do_execute_actions':
> > >> actions.c:(.text+0x1d5c): undefined reference to `psample_sample_packet'
> >
>
> Thanks robot!
>
> OK, I think I know what's wrong. There is an optional dependency with
> PSAMPLE. Openvswitch module does compile without PSAMPLE but there is a
> link error if OPENVSWITCH=y and PSAMPLE=m.
>
> Looking into how to express this in the Kconfig, I'm planning to add the
> following to the next version of the series.
>
> diff --git a/net/openvswitch/Kconfig b/net/openvswitch/Kconfig
> index 29a7081858cd..2535f3f9f462 100644
> --- a/net/openvswitch/Kconfig
> +++ b/net/openvswitch/Kconfig
> @@ -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
>
Thanks Adrián,
I both agree that should work, and tested with the config at the link above
and found that it does work.
On Wed, Jun 05, 2024 at 08:51:17PM GMT, Simon Horman wrote:
> On Mon, Jun 03, 2024 at 08:56:39PM +0200, 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 <[email protected]>
>
> Hi Adrian,
>
> Some minor nits from my side.
>
> ...
>
> > 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)
> > +
> > +
>
> nit: One blank line is enough.
>
Ack.
> Flagged by checkpatch.pl
>
> > /**
> > * 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_*. */
>
> nit: Please add OVS_ACTION_ATTR_EMIT_SAMPLE to the Kenrel doc
> for this structure.
>
Thanks for spotting this. Will do.
> >
> > __OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
> > * from userspace. */
>
> ...
>
Adrian Moreno <[email protected]> writes:
> 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 <[email protected]>
> ---
I saw some of the nits Simon raised - I'll add one more below.
I haven't gone through the series thoroughly enough to make a detailed
review.
> 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;
Why this return here? Doesn't seem used anywhere else.
> +}
> +
> /* 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;
On Mon, Jun 10, 2024 at 11:46:14AM GMT, Aaron Conole wrote:
> Adrian Moreno <[email protected]> writes:
>
> > 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 <[email protected]>
> > ---
>
> I saw some of the nits Simon raised - I'll add one more below.
>
> I haven't gone through the series thoroughly enough to make a detailed
> review.
>
> > 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;
>
> Why this return here? Doesn't seem used anywhere else.
>
It is being used in "do_execute_actions", right?
All non-skb-consuming actions set the value of "err" and break from the
switch-case so that the the packet is dropped with OVS_DROP_ACTION_ERROR reason.
Am i missing something?
> > +}
> > +
> > /* 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;
>
Adrián Moreno <[email protected]> writes:
> On Mon, Jun 10, 2024 at 11:46:14AM GMT, Aaron Conole wrote:
>> Adrian Moreno <[email protected]> writes:
>>
>> > 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 <[email protected]>
>> > ---
>>
>> I saw some of the nits Simon raised - I'll add one more below.
>>
>> I haven't gone through the series thoroughly enough to make a detailed
>> review.
>>
>> > 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;
>>
>> Why this return here? Doesn't seem used anywhere else.
>>
>
> It is being used in "do_execute_actions", right?
> All non-skb-consuming actions set the value of "err" and break from the
> switch-case so that the the packet is dropped with OVS_DROP_ACTION_ERROR reason.
>
> Am i missing something?
I think so. For example, it isn't used when the function cannot
possibly error.
see the following cases:
OVS_ACTION_ATTR_HASH
OVS_ACTION_ATTR_TRUNC
As you note, these can consume SKB so also don't bother setting err,
because they will need to return anyway:
OVS_ACTION_ATTR_USERSPACE
OVS_ACTION_ATTR_OUTPUT
OVS_ACTION_ATTR_DROP
And even the following does a weird thing:
OVS_ACTION_ATTR_CT
because sometimes it will consume, and sometimes not.
I think if there isn't a possibility of error being generated (and I
guess from the code I see there isn't), then it shouldn't return a
useless code, since err will be 0 on each iteration of the loop.
>> > +}
>> > +
>> > /* 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;
>>
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
On Tue, Jun 11, 2024 at 09:54:49AM GMT, Aaron Conole wrote:
> Adrián Moreno <[email protected]> writes:
>
> > On Mon, Jun 10, 2024 at 11:46:14AM GMT, Aaron Conole wrote:
> >> Adrian Moreno <[email protected]> writes:
> >>
> >> > 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 <[email protected]>
> >> > ---
> >>
> >> I saw some of the nits Simon raised - I'll add one more below.
> >>
> >> I haven't gone through the series thoroughly enough to make a detailed
> >> review.
> >>
> >> > 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;
> >>
> >> Why this return here? Doesn't seem used anywhere else.
> >>
> >
> > It is being used in "do_execute_actions", right?
> > All non-skb-consuming actions set the value of "err" and break from the
> > switch-case so that the the packet is dropped with OVS_DROP_ACTION_ERROR reason.
> >
> > Am i missing something?
>
> I think so. For example, it isn't used when the function cannot
> possibly error.
>
> see the following cases:
>
> OVS_ACTION_ATTR_HASH
> OVS_ACTION_ATTR_TRUNC
>
> As you note, these can consume SKB so also don't bother setting err,
> because they will need to return anyway:
>
> OVS_ACTION_ATTR_USERSPACE
> OVS_ACTION_ATTR_OUTPUT
> OVS_ACTION_ATTR_DROP
>
> And even the following does a weird thing:
>
> OVS_ACTION_ATTR_CT
>
> because sometimes it will consume, and sometimes not.
>
> I think if there isn't a possibility of error being generated (and I
> guess from the code I see there isn't), then it shouldn't return a
> useless code, since err will be 0 on each iteration of the loop.
>
Oh, so you meant it's actualy not being set. Now I get you.
Yes. I figured that could change in the future so I left the structure
of returning an error just in case, but it's true that currently the
function cannot fail.
I'll get rid of it.
> >> > +}
> >> > +
> >> > /* 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;
> >>
> >
> > _______________________________________________
> > dev mailing list
> > [email protected]
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
On Mon, Jun 03, 2024 at 08:56:39PM +0200, 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 <[email protected]>
...
> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
...
> @@ -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;
> }
Hi Adrian,
execute_emit_sample always returns 0, and it seems that err will always
be 0 when the code above is executed. So perhaps the return type
of execute_emit_sample could be changed to void and the code above be
updated not to set err.
Other than that, which I don't feel particularly strongly about,
this looks good to me.
...