On 27 Jun 2024, at 12:45, Adrián Moreno wrote:
> On Wed, Jun 26, 2024 at 02:08:27PM GMT, Eelco Chaudron wrote:
>> On 5 Jun 2024, at 22:23, Adrian Moreno wrote:
>>
>>> Add support for parsing and formatting the new action.
>>>
>>> Also, flag OVS_ACTION_ATTR_SAMPLE as requiring datapath assistance if it
>>> contains a nested OVS_ACTION_ATTR_EMIT_SAMPLE. The reason is that the
>>> sampling rate form the parent "sample" is made available to the nested
>>> "emit_sample" by the kernel.
>>
>> Hi Adrian,
>>
>> Thanks for this series! This email kicks off my review of the series,
>> see comments below and in the other patches.
>>
>> Cheers,
>>
>> Eelco
>>
>>> Signed-off-by: Adrian Moreno <amore...@redhat.com>
>>> ---
>>> include/linux/openvswitch.h | 25 +++++++++
>>> lib/dpif-netdev.c | 1 +
>>> lib/dpif.c | 1 +
>>> lib/odp-execute.c | 25 ++++++++-
>>> lib/odp-util.c | 103 +++++++++++++++++++++++++++++++++++
>>> lib/odp-util.h | 3 +
>>> ofproto/ofproto-dpif-ipfix.c | 1 +
>>> ofproto/ofproto-dpif-sflow.c | 1 +
>>> python/ovs/flow/odp.py | 8 +++
>>> tests/odp.at | 16 ++++++
>>> 10 files changed, 183 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
>>> index d9fb991ef..b4e0647bd 100644
>>> --- a/include/linux/openvswitch.h
>>> +++ b/include/linux/openvswitch.h
>>> @@ -992,6 +992,30 @@ 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 to limit the size of the packet being emitted.
>>
>> I'll start the discussion again on the naming. The name "emit_sample()"
>> does not seem appropriate. This function's primary role is to copy the
>> packet and send it to a local collector, which varies depending on the
>> datapath. For the kernel datapath, this collector is psample, while for
>> userspace, it will likely be some kind of probe. This action is distinct
>> from the sample() action by design; it is a standalone action that can
>> be combined with others.
>>
>> Furthermore, the action itself does not involve taking a sample; it
>> consistently pushes the packet to the local collector. Therefore, I
>> suggest renaming "emit_sample()" to "emit_local()". This same goes for
>> all the derivative ATTR naming.
>>
>
> Let's discuss this in the kernel ml.
>
>>> + */
>>> +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. */
>>
>> Fix comment alignment? Maybe also change the order to be alphabetical?
>>
>
> What do you mean by comment alignment?
Well you are using tabs to index which might result in it looking like this:
+ OVS_EMIT_SAMPLE_ATTR_GROUP, /* u32 number. */
+ OVS_EMIT_SAMPLE_ATTR_COOKIE, /* Optional, user specified cookie. */
(Most) of the other comments use spaces after the definition.
>>> + __OVS_EMIT_SAMPLE_ATTR_MAX
>>> +};
>>> +
>>> +#define OVS_EMIT_SAMPLE_ATTR_MAX (__OVS_EMIT_SAMPLE_ATTR_MAX - 1)
>>> +
>>> +
>>> /**
>>> * enum ovs_action_attr - Action types.
>>> *
>>> @@ -1087,6 +1111,7 @@ 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 xlate_error. */
>>> + OVS_ACTION_ATTR_EMIT_SAMPLE, /* Nested OVS_EMIT_SAMPLE_ATTR_*. */
>>>
>>> #ifndef __KERNEL__
>>> OVS_ACTION_ATTR_TUNNEL_PUSH, /* struct ovs_action_push_tnl*/
>>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
>>> index c7f9e1490..c1171890c 100644
>>> --- a/lib/dpif-netdev.c
>>> +++ b/lib/dpif-netdev.c
>>> @@ -9519,6 +9519,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch
>>> *packets_,
>>> case OVS_ACTION_ATTR_DROP:
>>> case OVS_ACTION_ATTR_ADD_MPLS:
>>> case OVS_ACTION_ATTR_DEC_TTL:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> case __OVS_ACTION_ATTR_MAX:
>>> OVS_NOT_REACHED();
>>> }
>>> diff --git a/lib/dpif.c b/lib/dpif.c
>>> index 23eb18495..489d6a095 100644
>>> --- a/lib/dpif.c
>>> +++ b/lib/dpif.c
>>> @@ -1192,6 +1192,7 @@ dpif_execute_helper_cb(void *aux_, struct
>>> dp_packet_batch *packets_,
>>> case OVS_ACTION_ATTR_TUNNEL_PUSH:
>>> case OVS_ACTION_ATTR_TUNNEL_POP:
>>> case OVS_ACTION_ATTR_USERSPACE:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> case OVS_ACTION_ATTR_RECIRC: {
>>> struct dpif_execute execute;
>>> struct ofpbuf execute_actions;
>>> diff --git a/lib/odp-execute.c b/lib/odp-execute.c
>>> index 081e4d432..967abfd0a 100644
>>> --- a/lib/odp-execute.c
>>> +++ b/lib/odp-execute.c
>>> @@ -818,13 +818,13 @@ requires_datapath_assistance(const struct nlattr *a)
>>> case OVS_ACTION_ATTR_RECIRC:
>>> case OVS_ACTION_ATTR_CT:
>>> case OVS_ACTION_ATTR_METER:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> return true;
>>>
>>> case OVS_ACTION_ATTR_SET:
>>> case OVS_ACTION_ATTR_SET_MASKED:
>>> case OVS_ACTION_ATTR_PUSH_VLAN:
>>> case OVS_ACTION_ATTR_POP_VLAN:
>>> - case OVS_ACTION_ATTR_SAMPLE:
>>> case OVS_ACTION_ATTR_HASH:
>>> case OVS_ACTION_ATTR_PUSH_MPLS:
>>> case OVS_ACTION_ATTR_POP_MPLS:
>>> @@ -841,6 +841,28 @@ requires_datapath_assistance(const struct nlattr *a)
>>> case OVS_ACTION_ATTR_DROP:
>>> return false;
>>>
>>> + case OVS_ACTION_ATTR_SAMPLE: {
>>> + /* Nested "emit_sample" actions rely on the datapath executing the
>>> + * parent "sample", storing the probability and making it available
>>> + * when the nested "emit_sample" is run.
>>> + */
>>
>> Comments in this file have the closing mark on the last line, so please do
>> this here also.
>>
>
> Ack
>
>>> + const struct nlattr *attr;
>>> + unsigned int left;
>>
>> Please add a new line after variable declarations.
>
> Ack.
>>
>>> + NL_NESTED_FOR_EACH (attr, left, a) {
>>
>> Also can we get a test case for this code path? The patch 9/9 is not hitting
>> this.
>>
>
> I know, I have been thinking in ways to test this. Ideally the test
> should be to add "debug_slow" to make the execution go to userspace but
> then add "sample(prob=X,action(emit_sample()))" and check the emitted
> smaple contains the right probability (which indicates the "sample" was
> also executed in the kernel.
>
> However, even if I put a probability of 0xFFFE that gives the test
> 0.0015% changes of failing...
>
> Anyway, I guess sending enough packets and checking at least some are
> received can reduce the probability to something negligible.
Will send it always (100%) not work?
>>> + if (nl_attr_type(attr) == OVS_SAMPLE_ATTR_ACTIONS) {
>>> + const struct nlattr *act;
>>> + unsigned int act_left;
>>> +
>>> + NL_NESTED_FOR_EACH (act, act_left, attr) {
>>> + if (nl_attr_type(act) == OVS_ACTION_ATTR_EMIT_SAMPLE) {
>>> + return true;
>>> + }
>>> + }
>>> + }
>>> + }
>>> + return false;
>>> + }
>>> +
>>> case OVS_ACTION_ATTR_UNSPEC:
>>> case __OVS_ACTION_ATTR_MAX:
>>> OVS_NOT_REACHED();
>>> @@ -1229,6 +1251,7 @@ odp_execute_actions(void *dp, struct dp_packet_batch
>>> *batch, bool steal,
>>> case OVS_ACTION_ATTR_CT:
>>> case OVS_ACTION_ATTR_UNSPEC:
>>> case OVS_ACTION_ATTR_DEC_TTL:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> case __OVS_ACTION_ATTR_MAX:
>>> /* The following actions are handled by the scalar implementation.
>>> */
>>> case OVS_ACTION_ATTR_POP_VLAN:
>>> diff --git a/lib/odp-util.c b/lib/odp-util.c
>>> index 724e6f2bc..02452083f 100644
>>> --- a/lib/odp-util.c
>>> +++ b/lib/odp-util.c
>>> @@ -145,6 +145,7 @@ odp_action_len(uint16_t type)
>>> case OVS_ACTION_ATTR_ADD_MPLS: return sizeof(struct
>>> ovs_action_add_mpls);
>>> case OVS_ACTION_ATTR_DEC_TTL: return ATTR_LEN_VARIABLE;
>>> case OVS_ACTION_ATTR_DROP: return sizeof(uint32_t);
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE: return ATTR_LEN_VARIABLE;
>>>
>>> case OVS_ACTION_ATTR_UNSPEC:
>>> case __OVS_ACTION_ATTR_MAX:
>>> @@ -1150,6 +1151,36 @@ format_dec_ttl_action(struct ds *ds, const struct
>>> nlattr *attr,
>>> ds_put_format(ds, "))");
>>> }
>>>
>>> +static void
>>> +format_odp_emit_sample_action(struct ds *ds, const struct nlattr *attr)
>>> +{
>>> + const struct nlattr *a;
>>> + unsigned int left;
>>> +
>>> + ds_put_cstr(ds, "emit_sample(");
>>> +
>>> + NL_ATTR_FOR_EACH (a, left,
>>> + nl_attr_get(attr), nl_attr_get_size(attr)) {
>>> + switch (a->nla_type) {
>>> + case OVS_EMIT_SAMPLE_ATTR_GROUP:
>>> + ds_put_format(ds, "group=%"PRIu32",", nl_attr_get_u32(a));
>>> + break;
>>> + case OVS_EMIT_SAMPLE_ATTR_COOKIE: {
>>> + const uint8_t *cookie = nl_attr_get(a);
>>> + int i;
>>> +
>>> + ds_put_cstr(ds, "cookie=");
>>> + for (i = 0; i < nl_attr_get_size(a); i++) {
>>> + ds_put_format(ds, "%02x", cookie[i]);
>>> + }
>>
>> There is a ds_put_hex() function, it adds '0x' which I guess is not desired
>> here (or maybe we should as it's more clear its a hex string).
>>
>
> Ack.
>
>>> + break;
>>> + }
>>> + }
>>
>> nit: Maybe swap the two case statements to avoid the odd looking double }.
>
> Ack.
>
>>> + }
>>> + ds_chomp(ds, ',');
>>> + ds_put_char(ds, ')');
>>> +}
>>> +
>>> static void
>>> format_odp_action(struct ds *ds, const struct nlattr *a,
>>> const struct hmap *portno_names)
>>> @@ -1309,6 +1340,9 @@ format_odp_action(struct ds *ds, const struct nlattr
>>> *a,
>>> case OVS_ACTION_ATTR_DROP:
>>> ds_put_cstr(ds, "drop");
>>> break;
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> + format_odp_emit_sample_action(ds, a);
>>> + break;
>>> case OVS_ACTION_ATTR_UNSPEC:
>>> case __OVS_ACTION_ATTR_MAX:
>>> default:
>>> @@ -2358,6 +2392,50 @@ out:
>>> return ret;
>>> }
>>>
>>> +static int
>>> +parse_odp_emit_sample_action(const char *s, struct ofpbuf *actions)
>>> +{
>>> + uint8_t cookie[OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE];
>>> + char buf[2 * OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE + 1];
>>
>> Reverse Christmas tree order.
>>
>
> Ack.
>
>>> + bool has_group = false;
>>> + size_t cookie_len = 0;
>>> + uint32_t group;
>>> + int n = 0;
>>> +
>>> + if (!ovs_scan_len(s, &n, "emit_sample(")) {
>>> + return -EINVAL;
>>> + }
>>> +
>>> + while (s[n] != ')') {
>>> + n += strspn(s + n, delimiters);
>>> +
>>> + if (!has_group && ovs_scan_len(s, &n, "group=%"SCNi32, &group)) {
>>> + has_group = true;
>>> + continue;
>>> + }
>>> +
>>> + if (!cookie_len &&
>>> + ovs_scan_len(s, &n, "cookie=%32[0-9a-fA-F]", buf) && n > 7) {
>>> + struct ofpbuf b;
>>> +
>>> + ofpbuf_use_stub(&b, cookie, OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE);
>>> + ofpbuf_put_hex(&b, buf, &cookie_len);
>>> + ofpbuf_uninit(&b);
>>> + continue;
>>> + }
>>> + return -EINVAL;
>>> + }
>>> + n++;
>>> +
>>> + if (!has_group) {
>>> + return -EINVAL;
>>> + }
>>> +
>>> + odp_put_emit_sample_action(actions, group, cookie_len ? cookie : NULL,
>>> + cookie_len);
>>> + return n;
>>> +}
>>> +
>>> static int
>>> parse_action_list(struct parse_odp_context *context, const char *s,
>>> struct ofpbuf *actions)
>>> @@ -2719,6 +2797,12 @@ parse_odp_action__(struct parse_odp_context
>>> *context, const char *s,
>>> }
>>> }
>>>
>>> + {
>>
>> You don' t need the extra {} set here, it's only needed if you have local
>> variables defined. See pop_vlan for example.
>>
>
> Looking at other actions in this function (e.g: "clone", "push_nsh",
> "ct_clear") I thought "I don't see the reason but it looks like someone
> did this on purpose". I missed other counter-examples. Will remove them.
Thanks, yes we might need to cleanup some others.
>>> + if (!strncmp(s, "emit_sample(", 12)) {
>>> + return parse_odp_emit_sample_action(s, actions);
>>> + }
>>> + }
>>> +
>>> {
>>> struct ovs_action_push_tnl data;
>>> int n;
>>> @@ -7828,6 +7912,25 @@ odp_put_tnl_push_action(struct ofpbuf *odp_actions,
>>> nl_msg_put_unspec(odp_actions, OVS_ACTION_ATTR_TUNNEL_PUSH, data,
>>> size);
>>> }
>>>
>>> +void
>>> +odp_put_emit_sample_action(struct ofpbuf *odp_actions,
>>> + uint32_t group_id,
>>> + uint8_t *cookie,
>>> + size_t cookie_len)
>>> +{
>>> + size_t offset = nl_msg_start_nested_with_flag(odp_actions,
>>> +
>>> OVS_ACTION_ATTR_EMIT_SAMPLE);
>>> +
>>> + nl_msg_put_u32(odp_actions, OVS_EMIT_SAMPLE_ATTR_GROUP, group_id);
>>> + if (cookie && cookie_len) {
>>> + ovs_assert(cookie_len <= OVS_EMIT_SAMPLE_COOKIE_MAX_SIZE);
>>> + nl_msg_put_unspec(odp_actions, OVS_EMIT_SAMPLE_ATTR_COOKIE, cookie,
>>> + cookie_len);
>>> + }
>>> +
>>> + nl_msg_end_nested(odp_actions, offset);
>>> +}
>>> +
>>>
>>> /* The commit_odp_actions() function and its helpers. */
>>>
>>> diff --git a/lib/odp-util.h b/lib/odp-util.h
>>> index 8c7baa680..2159f0897 100644
>>> --- a/lib/odp-util.h
>>> +++ b/lib/odp-util.h
>>> @@ -376,6 +376,9 @@ void odp_put_pop_eth_action(struct ofpbuf *odp_actions);
>>> void odp_put_push_eth_action(struct ofpbuf *odp_actions,
>>> const struct eth_addr *eth_src,
>>> const struct eth_addr *eth_dst);
>>> +void odp_put_emit_sample_action(struct ofpbuf *odp_actions,
>>> + uint32_t group_id, uint8_t *cookie,
>>> + size_t cookie_len);
>>>
>>> static inline void odp_decode_gbp_raw(uint32_t gbp_raw,
>>> ovs_be16 *id,
>>> diff --git a/ofproto/ofproto-dpif-ipfix.c b/ofproto/ofproto-dpif-ipfix.c
>>> index cd65dae7e..15e92ba74 100644
>>> --- a/ofproto/ofproto-dpif-ipfix.c
>>> +++ b/ofproto/ofproto-dpif-ipfix.c
>>> @@ -3136,6 +3136,7 @@ dpif_ipfix_read_actions(const struct flow *flow,
>>> case OVS_ACTION_ATTR_DROP:
>>> case OVS_ACTION_ATTR_ADD_MPLS:
>>> case OVS_ACTION_ATTR_DEC_TTL:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> case __OVS_ACTION_ATTR_MAX:
>>> default:
>>> break;
>>> diff --git a/ofproto/ofproto-dpif-sflow.c b/ofproto/ofproto-dpif-sflow.c
>>> index 4a68e9b94..9db499fd4 100644
>>> --- a/ofproto/ofproto-dpif-sflow.c
>>> +++ b/ofproto/ofproto-dpif-sflow.c
>>> @@ -1237,6 +1237,7 @@ dpif_sflow_read_actions(const struct flow *flow,
>>> case OVS_ACTION_ATTR_DROP:
>>> case OVS_ACTION_ATTR_ADD_MPLS:
>>> case OVS_ACTION_ATTR_DEC_TTL:
>>> + case OVS_ACTION_ATTR_EMIT_SAMPLE:
>>> case __OVS_ACTION_ATTR_MAX:
>>> default:
>>> break;
>>> diff --git a/python/ovs/flow/odp.py b/python/ovs/flow/odp.py
>>> index 7d9b165d4..896ae34bd 100644
>>> --- a/python/ovs/flow/odp.py
>>> +++ b/python/ovs/flow/odp.py
>>> @@ -343,6 +343,14 @@ class ODPFlow(Flow):
>>> }
>>> )
>>> ),
>>> + "emit_sample": nested_kv_decoder(
>>> + KVDecoders(
>>> + {
>>> + "group": decode_int,
>>> + "cookie": decode_default,
>>> + }
>>> + )
>>> + )
>>> }
>>>
>>> _decoders["sample"] = nested_kv_decoder(
>>> diff --git a/tests/odp.at b/tests/odp.at
>>> index ba20604e4..e5c2ee07c 100644
>>> --- a/tests/odp.at
>>> +++ b/tests/odp.at
>>> @@ -393,6 +393,10 @@ check_pkt_len(size=200,gt(ct(nat)),le(drop))
>>>
>>> check_pkt_len(size=200,gt(set(eth(src=00:01:02:03:04:05,dst=10:11:12:13:14:15))),le(set(eth(src=00:01:02:03:04:06,dst=10:11:12:13:14:16))))
>>> lb_output(1)
>>> add_mpls(label=200,tc=7,ttl=64,bos=1,eth_type=0x8847)
>>> +emit_sample(group=12,cookie=01020304050607080910111213141516)
>>> +emit_sample(group=12)
>>> +sample(sample=50.0%,actions(emit_sample(group=12,cookie=01020304)))
>>> +sample(sample=50.0%,actions(userspace(pid=42,userdata(0102030400000000)),emit_sample(group=12)))
>>> ])
>>> AT_CHECK_UNQUOTED([ovstest test-odp parse-actions < actions.txt], [0],
>>> [`cat actions.txt`
>>> @@ -406,11 +410,23 @@ AT_DATA([actions.txt], [dnl
>>> encap_nsh@:{@
>>>
>>> tnl_push(tnl_port(6),header(size=94,type=112,eth(dst=f8:bc:12:44:34:b6,src=f8:bc:12:46:58:e0,dl_type=0x86dd),ipv6(src=2001:cafe::88,dst=2001:cafe::92,label=0,proto=43,tclass=0x0,hlimit=64),srv6(segments_left=2,segs(2001:cafe::90,2001:cafe::91))),out_port(1))
>>>
>>> tnl_push(tnl_port(6),header(size=126,type=112,eth(dst=f8:bc:12:44:34:b6,src=f8:bc:12:46:58:e0,dl_type=0x86dd),ipv6(src=2001:cafe::88,dst=2001:cafe::92,label=0,proto=43,tclass=0x0,hlimit=64),srv6(segments_left=2,segs(2001:cafe::90,2001:cafe::91,2001:cafe::92,2001:cafe::93))),out_port(1))
>>> +emit_sample(group_id=12,cookie=0102030405060708090a0b0c0d0e0f0f0f)
>>> +emit_sample(cookie=010203)
>>> +emit_sample(group=12,cookie=010203,group=12)
>>> +emit_sample(group=abc)
>>> +emit_sample(group=12,cookie=wrong)
>>> +emit_sample()
>>> ])
>>> AT_CHECK_UNQUOTED([ovstest test-odp parse-actions < actions.txt], [0], [dnl
>>> odp_actions_from_string: error
>>> odp_actions_from_string: error
>>> odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> +odp_actions_from_string: error
>>> ])
>>> AT_CLEANUP
>>>
>>> --
>>> 2.45.1
>>
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