Commit 85674625 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

tcp_metrics: add netlink protocol spec in YAML 



Add a protocol spec for tcp_metrics, so that it's accessible via YNL.
Useful at the very least for testing fixes.

In this episode of "10,000 ways to complicate netlink" the metric
nest has defines which are off by 1. iproute2 does:

        struct rtattr *m[TCP_METRIC_MAX + 1 + 1];

        parse_rtattr_nested(m, TCP_METRIC_MAX + 1, a);

        for (i = 0; i < TCP_METRIC_MAX + 1; i++) {
                // ...
                attr = m[i + 1];

This is too weird to support in YNL, add a new set of defines
with _correct_ values to the official kernel header.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarDonald Hunter <donald.hunter@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7c811005

Documentation/netlink/specs/tcp_metrics.yaml

0 → 100644
+169 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)



name: tcp_metrics



protocol: genetlink-legacy



doc: |

  Management interface for TCP metrics.



c-family-name: tcp-metrics-genl-name

c-version-name: tcp-metrics-genl-version

max-by-define: true

kernel-policy: global



definitions:

  -

    name: tcp-fastopen-cookie-max

    type: const

    value: 16



attribute-sets:

  -

    name: tcp-metrics

    name-prefix: tcp-metrics-attr-

    attributes:

      -

        name: addr-ipv4

        type: u32

        byte-order: big-endian

        display-hint: ipv4

      -

        name: addr-ipv6

        type: binary

        checks:

          min-len: 16

        byte-order: big-endian

        display-hint: ipv6

      -

        name: age

        type: u64

      -

        name: tw-tsval

        type: u32

        doc: unused

      -

        name: tw-ts-stamp

        type: s32

        doc: unused

      -

        name: vals

        type: nest

        nested-attributes: metrics

      -

        name: fopen-mss

        type: u16

      -

        name: fopen-syn-drops

        type: u16

      -

        name: fopen-syn-drop-ts

        type: u64

      -

        name: fopen-cookie

        type: binary

        checks:

          min-len: tcp-fastopen-cookie-max

      -

        name: saddr-ipv4

        type: u32

        byte-order: big-endian

        display-hint: ipv4

      -

        name: saddr-ipv6

        type: binary

        checks:

          min-len: 16

        byte-order: big-endian

        display-hint: ipv6

      -

        name: pad

        type: pad



  -

    name: metrics

    # Intentionally don't define the name-prefix, see below.

    doc: |

      Attributes with metrics. Note that the values here do not match

      the TCP_METRIC_* defines in the kernel, because kernel defines

      are off-by one (e.g. rtt is defined as enum 0, while netlink carries

      attribute type 1).

    attributes:

      -

        name: rtt

        type: u32

        doc: |

          Round Trip Time (RTT), in msecs with 3 bits fractional

          (left-shift by 3 to get the msec value).

      -

        name: rttvar

        type: u32

        doc: |

          Round Trip Time VARiance (RTT), in msecs with 2 bits fractional

          (left-shift by 2 to get the msec value).

      -

        name: ssthresh

        type: u32

        doc: Slow Start THRESHold.

      -

        name: cwnd

        type: u32

        doc: Congestion Window.

      -

        name: reodering

        type: u32

        doc: Reodering metric.

      -

        name: rtt-us

        type: u32

        doc: |

          Round Trip Time (RTT), in usecs, with 3 bits fractional

          (left-shift by 3 to get the msec value).

      -

        name: rttvar-us

        type: u32

        doc: |

          Round Trip Time (RTT), in usecs, with 2 bits fractional

          (left-shift by 3 to get the msec value).



operations:

  list:

    -

      name: get

      doc: Retrieve metrics.

      attribute-set: tcp-metrics



      dont-validate: [ strict, dump ]



      do:

        request: &sel_attrs

          attributes:

            - addr-ipv4

            - addr-ipv6

            - saddr-ipv4

            - saddr-ipv6

        reply: &all_attrs

          attributes:

            - addr-ipv4

            - addr-ipv6

            - saddr-ipv4

            - saddr-ipv6

            - age

            - vals

            - fopen-mss

            - fopen-syn-drops

            - fopen-syn-drop-ts

            - fopen-cookie

      dump:

        reply: *all_attrs



    -

      name: del

      doc: Delete metrics.

      attribute-set: tcp-metrics



      dont-validate: [ strict, dump ]

      flags: [ admin-perm ]



      do:

        request: *sel_attrs

include/uapi/linux/tcp_metrics.h

+16 −0
Original line number Diff line number Diff line
@@ -27,6 +27,22 @@ enum tcp_metric_index { 


#define TCP_METRIC_MAX	(__TCP_METRIC_MAX - 1)



/* Re-define enum tcp_metric_index, again, using the values carried

 * as netlink attribute types.

 */

enum {

	TCP_METRICS_A_METRICS_RTT = 1,

	TCP_METRICS_A_METRICS_RTTVAR,

	TCP_METRICS_A_METRICS_SSTHRESH,

	TCP_METRICS_A_METRICS_CWND,

	TCP_METRICS_A_METRICS_REODERING,

	TCP_METRICS_A_METRICS_RTT_US,

	TCP_METRICS_A_METRICS_RTTVAR_US,



	__TCP_METRICS_A_METRICS_MAX

};

#define TCP_METRICS_A_METRICS_MAX (__TCP_METRICS_A_METRICS_MAX - 1)



enum {

	TCP_METRICS_ATTR_UNSPEC,

	TCP_METRICS_ATTR_ADDR_IPV4,		/* u32 */

tools/net/ynl/Makefile.deps

+1 −0
Original line number Diff line number Diff line
@@ -26,3 +26,4 @@ CFLAGS_nfsd:=$(call get_hdr_inc,_LINUX_NFSD_NETLINK_H,nfsd_netlink.h) 
CFLAGS_ovs_datapath:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)

CFLAGS_ovs_flow:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)

CFLAGS_ovs_vport:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)

CFLAGS_tcp_metrics:=$(call get_hdr_inc,_LINUX_TCP_METRICS_H,tcp_metrics.h)