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kuba-moodavem330
kuba-moo
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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: Jakub Kicinski <[email protected]> Reviewed-by: Donald Hunter <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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‎Documentation/netlink/specs/tcp_metrics.yaml

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# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
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name: tcp_metrics
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protocol: genetlink-legacy
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doc: |
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Management interface for TCP metrics.
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c-family-name: tcp-metrics-genl-name
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c-version-name: tcp-metrics-genl-version
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max-by-define: true
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kernel-policy: global
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definitions:
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-
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name: tcp-fastopen-cookie-max
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type: const
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value: 16
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attribute-sets:
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-
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name: tcp-metrics
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name-prefix: tcp-metrics-attr-
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attributes:
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-
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name: addr-ipv4
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type: u32
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byte-order: big-endian
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display-hint: ipv4
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-
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name: addr-ipv6
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type: binary
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checks:
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min-len: 16
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byte-order: big-endian
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display-hint: ipv6
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-
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name: age
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type: u64
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-
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name: tw-tsval
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type: u32
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doc: unused
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-
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name: tw-ts-stamp
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type: s32
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doc: unused
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-
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name: vals
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type: nest
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nested-attributes: metrics
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-
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name: fopen-mss
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type: u16
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-
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name: fopen-syn-drops
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type: u16
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-
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name: fopen-syn-drop-ts
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type: u64
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-
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name: fopen-cookie
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type: binary
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checks:
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min-len: tcp-fastopen-cookie-max
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-
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name: saddr-ipv4
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type: u32
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byte-order: big-endian
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display-hint: ipv4
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-
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name: saddr-ipv6
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type: binary
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checks:
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min-len: 16
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byte-order: big-endian
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display-hint: ipv6
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-
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name: pad
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type: pad
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-
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name: metrics
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# Intentionally don't define the name-prefix, see below.
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doc: |
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Attributes with metrics. Note that the values here do not match
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the TCP_METRIC_* defines in the kernel, because kernel defines
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are off-by one (e.g. rtt is defined as enum 0, while netlink carries
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attribute type 1).
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attributes:
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-
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name: rtt
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type: u32
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doc: |
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Round Trip Time (RTT), in msecs with 3 bits fractional
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(left-shift by 3 to get the msec value).
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-
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name: rttvar
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type: u32
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doc: |
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Round Trip Time VARiance (RTT), in msecs with 2 bits fractional
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(left-shift by 2 to get the msec value).
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-
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name: ssthresh
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type: u32
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doc: Slow Start THRESHold.
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-
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name: cwnd
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type: u32
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doc: Congestion Window.
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-
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name: reodering
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type: u32
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doc: Reodering metric.
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-
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name: rtt-us
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type: u32
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doc: |
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Round Trip Time (RTT), in usecs, with 3 bits fractional
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(left-shift by 3 to get the msec value).
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-
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name: rttvar-us
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type: u32
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doc: |
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Round Trip Time (RTT), in usecs, with 2 bits fractional
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(left-shift by 3 to get the msec value).
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operations:
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list:
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-
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name: get
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doc: Retrieve metrics.
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attribute-set: tcp-metrics
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dont-validate: [ strict, dump ]
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do:
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request: &sel_attrs
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attributes:
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- addr-ipv4
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- addr-ipv6
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- saddr-ipv4
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- saddr-ipv6
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reply: &all_attrs
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attributes:
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- addr-ipv4
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- addr-ipv6
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- saddr-ipv4
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- saddr-ipv6
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- age
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- vals
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- fopen-mss
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- fopen-syn-drops
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- fopen-syn-drop-ts
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- fopen-cookie
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dump:
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reply: *all_attrs
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-
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name: del
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doc: Delete metrics.
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attribute-set: tcp-metrics
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dont-validate: [ strict, dump ]
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flags: [ admin-perm ]
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do:
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request: *sel_attrs

‎include/uapi/linux/tcp_metrics.h

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@@ -27,6 +27,22 @@ enum tcp_metric_index {
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#define TCP_METRIC_MAX (__TCP_METRIC_MAX - 1)
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/* Re-define enum tcp_metric_index, again, using the values carried
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* as netlink attribute types.
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*/
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enum {
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TCP_METRICS_A_METRICS_RTT = 1,
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TCP_METRICS_A_METRICS_RTTVAR,
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TCP_METRICS_A_METRICS_SSTHRESH,
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TCP_METRICS_A_METRICS_CWND,
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TCP_METRICS_A_METRICS_REODERING,
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TCP_METRICS_A_METRICS_RTT_US,
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TCP_METRICS_A_METRICS_RTTVAR_US,
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__TCP_METRICS_A_METRICS_MAX
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};
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#define TCP_METRICS_A_METRICS_MAX (__TCP_METRICS_A_METRICS_MAX - 1)
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enum {
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TCP_METRICS_ATTR_UNSPEC,
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TCP_METRICS_ATTR_ADDR_IPV4, /* u32 */

‎tools/net/ynl/Makefile.deps

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@@ -26,3 +26,4 @@ CFLAGS_nfsd:=$(call get_hdr_inc,_LINUX_NFSD_NETLINK_H,nfsd_netlink.h)
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CFLAGS_ovs_datapath:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
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CFLAGS_ovs_flow:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
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CFLAGS_ovs_vport:=$(call get_hdr_inc,__LINUX_OPENVSWITCH_H,openvswitch.h)
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CFLAGS_tcp_metrics:=$(call get_hdr_inc,_LINUX_TCP_METRICS_H,tcp_metrics.h)

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