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?
> > + __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.
> > + 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.
> > + 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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