netstat: model legacy TcpExt counters removed from recent kernels - #863
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PAWSPassive, TCPPrequeued, TCPDirectCopyFromBacklog, TCPDirectCopyFromPrequeue, TCPPrequeueDropped, TCPLoss, TCPFACKReorder, TCPForwardRetrans, TCPHPHitsToUser and TCPSchedulerFailed are absent from the current kernel TcpExt table but are still printed by older kernels. Model them so consumers keep metric parity with older kernels; the parser stays additive (absent keys remain nil). See prometheus/node_exporter#3796. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com>
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procfs v0.22.0 includes prometheus/procfs#863, which models the 10 legacy TcpExt counters. With this bump, the explicit descriptors already present in netstat_descs_linux.go start populating for users whose field regex selects them, restoring parity with older kernels. Part of prometheus#3796. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com>
neoLsH
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procfs v0.22.0 includes prometheus/procfs#863, which models the 10 legacy TcpExt counters. With this bump, the explicit descriptors already present in netstat_descs_linux.go start populating for users whose field regex selects them, restoring parity with older kernels. Part of prometheus#3796. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com>
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* netstat: Use procfs parsers for netstat, snmp and snmp6 Replace the hand-written parsers for /proc/net/netstat, /proc/net/snmp and /proc/net/snmp6 with the parsers from prometheus/procfs (Proc.Netstat, Proc.Snmp and Proc.Snmp6). The statistics are read via /proc/self/net, which is equivalent to /proc/net (both are network-namespace local views of the current process), so the collected data is unchanged. Metrics are exposed by iterating the procfs statistics structs, the same approach the NFS collector uses: fields are *float64 and only the ones present on the system are exported, matching the previous behavior. The --collector.netstat.fields flag and the exported metric names are unchanged; the e2e golden output is identical. Signed-off-by: neoLsH <43921685+neoLsH@users.noreply.github.com> * netstat: use explicit package-level metric descriptors Replace the per-scrape prometheus.NewDesc calls with a pre-built map of explicit descriptors (netstat_descs_linux.go, generated from the procfs statistics structs), as requested in review. Collection still reflects over the procfs structs but looks up the descriptor by "<protocol>_<field>", so descriptors are allocated once and are source-visible literals for the AST-based doc generation. Metric names, help strings and types are unchanged. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com> * Bump procfs to v0.22.0 to populate legacy TcpExt descriptors procfs v0.22.0 includes prometheus/procfs#863, which models the 10 legacy TcpExt counters. With this bump, the explicit descriptors already present in netstat_descs_linux.go start populating for users whose field regex selects them, restoring parity with older kernels. Part of #3796. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com> * Add generator and drift test for the netstat descriptor table netstat_descs_linux.go was previously committed without its generator. Add an in-repo generator (netstat_descs_gen.go, a build-ignored program run via GOOS=linux go generate ./collector) that regenerates the explicit descriptor table from the procfs structs, mirroring the go:generate pattern used elsewhere in the Prometheus ecosystem. Add TestNetStatDescsInSync, a drift test that fails if the committed table diverges from the procfs structs (e.g. after a procfs upgrade) until the table is regenerated. Part of #3796. Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com> --------- Signed-off-by: neoLsH <43921685+neoLsH@users.noreply.github.com> Signed-off-by: 霏承 <huangleshu.hls@alibaba-inc.com>
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What
Add 10 legacy
TcpExtcounters to the/proc/net/netstatmodel and parser:PAWSPassive,TCPPrequeued,TCPDirectCopyFromBacklog,TCPDirectCopyFromPrequeue,TCPPrequeueDropped,TCPLoss,TCPFACKReorder,TCPForwardRetrans,TCPHPHitsToUser,TCPSchedulerFailed.Why
These counters are absent from the current kernel's
TcpExttable (none ofthem are in linus/master
include/uapi/linux/snmp.h), but older kernels stillprint them in
/proc/net/netstat. node_exporter is switching its netstatcollector to these parsers (prometheus/node_exporter#3796), and would
otherwise silently drop these metrics for users whose
--collector.netstat.fieldsregex selects them.Behavior
*float64and staynilwhen the kerneldoes not print them (all modern kernels), matching the optional-field
semantics from Replace float64 with *float64 for proc_netstat, proc_snmp and proc_snmp6 #464.
cases.
Out of scope
IcmpMsg/Icmp6Msgper-type counters: the kernel only prints non-zeroInTypeN/OutTypeNentries, so the set is host-dependent and open-ended —a fixed struct can't cover it (a map, like
NetDev, or an unknown-keysescape hatch would). Separate follow-up.
StatValuerefactor floated in netstat: Use procfs parsers for netstat, snmp and snmp6 node_exporter#3796: changingall netstat/snmp field types would be a breaking API change for existing
consumers; separate discussion.
Note on scope: this PR closes the backward gap (counters older kernels print that
were never modeled). procfs's
TcpExtalso lags the current kernel in the otherdirection (e.g.
TCPDelivered,TCPAckCompressed,TCPZeroWindowDrop,TCPBacklogCoalesce,BeyondWindow,TCPTimeoutRehash,TCPDSACKRecvSegs,TCPMigrateReq*,TCPAO*are printed by modern kernels but not modeled). Thatforward lag is procfs's ordinary upkeep, pre-exists this change, and affects all
consumers; it is deliberately out of scope here rather than bundled in.