net: psample: allow using rate as probability

Although not explicitly documented in the psample module itself, the
definition of PSAMPLE_ATTR_SAMPLE_RATE seems inherited from act_sample.

Quoting tc

net: psample: allow using rate as probability

Although not explicitly documented in the psample module itself, the
definition of PSAMPLE_ATTR_SAMPLE_RATE seems inherited from act_sample.

Quoting tc-sample(8):
"RATE of 100 will lead to an average of one sampled packet out of every
100 observed."

With this semantics, the rates that we can express with an unsigned
32-bits number are very unevenly distributed and concentrated towards
"sampling few packets".
For example, we can express a probability of 2.32E-8% but we
cannot express anything between 100% and 50%.

For sampling applications that are capable of sampling a decent
amount of packets, this sampling rate semantics is not very useful.

Add a new flag to the uAPI that indicates that the sampling rate is
expressed in scaled probability, this is:
- 0 is 0% probability, no packets get sampled.
- U32_MAX is 100% probability, all packets get sampled.

Reviewed-by: Aaron Conole <[email protected]>
Acked-by: Eelco Chaudron <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Signed-off-by: Adrian Moreno <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: psample: add user cookie

Add a user cookie to the sample metadata so that sample emitters can
provide more contextual information to samples.

If present, send the user cookie in a new attribut

net: psample: add user cookie

Add a user cookie to the sample metadata so that sample emitters can
provide more contextual information to samples.

If present, send the user cookie in a new attribute:
PSAMPLE_ATTR_USER_COOKIE.

Reviewed-by: Michal Kubiak <[email protected]>
Acked-by: Eelco Chaudron <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Signed-off-by: Adrian Moreno <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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psample: Fix user API breakage

Cited commit added a new attribute before the existing group reference
count attribute, thereby changing its value and breaking existing
applications on new kernels.

psample: Fix user API breakage

Cited commit added a new attribute before the existing group reference
count attribute, thereby changing its value and breaking existing
applications on new kernels.

Before:

# psample -l
libpsample ERROR psample_group_foreach: failed to recv message: Operation not supported

After:

# psample -l
Group Num Refcount Group Seq
1 1 0

Fix by restoring the value of the old attribute and remove the
misleading comments from the enumerator to avoid future bugs.

Cc: [email protected]
Fixes: d8bed686ab96 ("net: psample: Add tunnel support")
Signed-off-by: Ido Schimmel <[email protected]>
Reported-by: Adiel Bidani <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Reviewed-by: Petr Machata <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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psample: Add additional metadata attributes

Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a

psample: Add additional metadata attributes

Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a 64-bit value
* End-to-end latency of the packet in nanoseconds resolution
* Software timestamp in nanoseconds resolution (always available)
* Packet's protocol. Needed for packet dissection in user space (always
available)

Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net: psample: Add tunnel support

Currently, psample can only send the packet bits after decapsulation.
The tunnel information is lost. Add the tunnel support.

If the sampled packet has no tunnel in

net: psample: Add tunnel support

Currently, psample can only send the packet bits after decapsulation.
The tunnel information is lost. Add the tunnel support.

If the sampled packet has no tunnel info, the behavior is the same as
before. If it has, add a nested metadata field named PSAMPLE_ATTR_TUNNEL
and include the tunnel subfields if applicable.

Increase the metadata length for sampled packet with the tunnel info.
If new subfields of tunnel info should be included, update the metadata
length accordingly.

Signed-off-by: Chris Mi <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine

License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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net: Introduce psample, a new genetlink channel for packet sampling

Add a general way for kernel modules to sample packets, without being tied
to any specific subsystem. This netlink channel can be

net: Introduce psample, a new genetlink channel for packet sampling

Add a general way for kernel modules to sample packets, without being tied
to any specific subsystem. This netlink channel can be used by tc,
iptables, etc. and allow to standardize packet sampling in the kernel.

For every sampled packet, the psample module adds the following metadata
fields:

PSAMPLE_ATTR_IIFINDEX - the packets input ifindex, if applicable

PSAMPLE_ATTR_OIFINDEX - the packet output ifindex, if applicable

PSAMPLE_ATTR_ORIGSIZE - the packet's original size, in case it has been
truncated during sampling

PSAMPLE_ATTR_SAMPLE_GROUP - the packet's sample group, which is set by the
user who initiated the sampling. This field allows the user to
differentiate between several samplers working simultaneously and
filter packets relevant to him

PSAMPLE_ATTR_GROUP_SEQ - sequence counter of last sent packet. The
sequence is kept for each group

PSAMPLE_ATTR_SAMPLE_RATE - the sampling rate used for sampling the packets

PSAMPLE_ATTR_DATA - the actual packet bits

The sampled packets are sent to the PSAMPLE_NL_MCGRP_SAMPLE multicast
group. In addition, add the GET_GROUPS netlink command which allows the
user to see the current sample groups, their refcount and sequence number.
This command currently supports only netlink dump mode.

Signed-off-by: Yotam Gigi <[email protected]>
Signed-off-by: Jiri Pirko <[email protected]>
Reviewed-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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