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Parse /proc/net/protocols (#347)
This patch adds support for extracting system socket metrics found only in /proc/net/protocols. The most interesting metrics found here are per-protocol socket counts along with the total memory in pages used by each. For TCP connections this data can be used to tune/monitor a system against the thresholds set in net.ipv4.tcp_mem. This file also exposes a pressure metric which indicates whether or not a protocol like TCP has entered memory pressure, which again is useful in troubleshooting things like memory pressure induced packet drops on loopback. Some additional albeit less interesting metrics that come out of this file include the size of each protocol's struct, and the maximum header size the kernel is willing to allocate. The additional columns enumerate capabilities per-protocol and are encoded as bools. Signed-off-by: Juan Bran <[email protected]>
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‎fixtures.ttar

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4 1FB3C 0 1282A8F 0
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Mode: 644
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# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Path: fixtures/proc/net/protocols
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Lines: 14
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protocol size sockets memory press maxhdr slab module cl co di ac io in de sh ss gs se re sp bi br ha uh gp em
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PACKET 1344 2 -1 NI 0 no kernel n n n n n n n n n n n n n n n n n n n
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PINGv6 1112 0 -1 NI 0 yes kernel y y y n n y n n y y y y n y y y y y n
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RAWv6 1112 1 -1 NI 0 yes kernel y y y n y y y n y y y y n y y y y n n
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UDPLITEv6 1216 0 57 NI 0 yes kernel y y y n y y y n y y y y n n n y y y n
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UDPv6 1216 10 57 NI 0 yes kernel y y y n y y y n y y y y n n n y y y n
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TCPv6 2144 1937 1225378 no 320 yes kernel y y y y y y y y y y y y y n y y y y y
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UNIX 1024 120 -1 NI 0 yes kernel n n n n n n n n n n n n n n n n n n n
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UDP-Lite 1024 0 57 NI 0 yes kernel y y y n y y y n y y y y y n n y y y n
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PING 904 0 -1 NI 0 yes kernel y y y n n y n n y y y y n y y y y y n
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RAW 912 0 -1 NI 0 yes kernel y y y n y y y n y y y y n y y y y n n
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UDP 1024 73 57 NI 0 yes kernel y y y n y y y n y y y y y n n y y y n
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TCP 1984 93064 1225378 yes 320 yes kernel y y y y y y y y y y y y y n y y y y y
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NETLINK 1040 16 -1 NI 0 no kernel n n n n n n n n n n n n n n n n n n n
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Mode: 444
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# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Directory: fixtures/proc/net/rpc
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Mode: 755
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# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

‎net_protocols.go

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// Copyright 2020 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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import (
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"bufio"
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"bytes"
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"fmt"
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"strconv"
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"strings"
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"github.com/prometheus/procfs/internal/util"
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)
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// NetProtocolStats stores the contents from /proc/net/protocols
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type NetProtocolStats map[string]NetProtocolStatLine
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// NetProtocolStatLine contains a single line parsed from /proc/net/protocols. We
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// only care about the first six columns as the rest are not likely to change
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// and only serve to provide a set of capabilities for each protocol.
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type NetProtocolStatLine struct {
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Name string // 0 The name of the protocol
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Size uint64 // 1 The size, in bytes, of a given protocol structure. e.g. sizeof(struct tcp_sock) or sizeof(struct unix_sock)
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Sockets int64 // 2 Number of sockets in use by this protocol
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Memory int64 // 3 Number of 4KB pages allocated by all sockets of this protocol
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Pressure int // 4 This is either yes, no, or NI (not implemented). For the sake of simplicity we treat NI as not experiencing memory pressure.
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MaxHeader uint64 // 5 Protocol specific max header size
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Slab bool // 6 Indicates whether or not memory is allocated from the SLAB
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ModuleName string // 7 The name of the module that implemented this protocol or "kernel" if not from a module
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Capabilities NetProtocolCapabilities
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}
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// NetProtocolCapabilities contains a list of capabilities for each protocol
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type NetProtocolCapabilities struct {
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Close bool // 8
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Connect bool // 9
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Disconnect bool // 10
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Accept bool // 11
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IoCtl bool // 12
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Init bool // 13
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Destroy bool // 14
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Shutdown bool // 15
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SetSockOpt bool // 16
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GetSockOpt bool // 17
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SendMsg bool // 18
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RecvMsg bool // 19
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SendPage bool // 20
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Bind bool // 21
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BacklogRcv bool // 22
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Hash bool // 23
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UnHash bool // 24
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GetPort bool // 25
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EnterMemoryPressure bool // 26
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}
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// NetProtocols reads stats from /proc/net/protocols and returns a map of
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// PortocolStatLine entries. As of this writing no official Linux Documentation
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// exists, however the source is fairly self-explanatory and the format seems
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// stable since its introduction in 2.6.12-rc2
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// Linux 2.6.12-rc2 - https://elixir.bootlin.com/linux/v2.6.12-rc2/source/net/core/sock.c#L1452
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// Linux 5.10 - https://elixir.bootlin.com/linux/v5.10.4/source/net/core/sock.c#L3586
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func (fs FS) NetProtocols() (NetProtocolStats, error) {
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data, err := util.ReadFileNoStat(fs.proc.Path("net/protocols"))
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if err != nil {
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return NetProtocolStats{}, err
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}
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return parseNetProtocols(bufio.NewScanner(bytes.NewReader(data)))
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}
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func parseNetProtocols(s *bufio.Scanner) (NetProtocolStats, error) {
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nps := NetProtocolStats{}
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// Skip the header line
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s.Scan()
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for s.Scan() {
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line, err := nps.parseLine(s.Text())
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if err != nil {
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return NetProtocolStats{}, err
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}
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nps[line.Name] = *line
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}
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return nps, nil
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}
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func (ps NetProtocolStats) parseLine(rawLine string) (*NetProtocolStatLine, error) {
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line := &NetProtocolStatLine{Capabilities: NetProtocolCapabilities{}}
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var err error
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const enabled = "yes"
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const disabled = "no"
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fields := strings.Fields(rawLine)
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line.Name = fields[0]
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line.Size, err = strconv.ParseUint(fields[1], 10, 64)
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if err != nil {
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return nil, err
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}
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line.Sockets, err = strconv.ParseInt(fields[2], 10, 64)
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if err != nil {
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return nil, err
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}
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line.Memory, err = strconv.ParseInt(fields[3], 10, 64)
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if err != nil {
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return nil, err
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}
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if fields[4] == enabled {
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line.Pressure = 1
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} else if fields[4] == disabled {
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line.Pressure = 0
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} else {
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line.Pressure = -1
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}
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line.MaxHeader, err = strconv.ParseUint(fields[5], 10, 64)
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if err != nil {
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return nil, err
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}
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if fields[6] == enabled {
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line.Slab = true
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} else if fields[6] == disabled {
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line.Slab = false
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} else {
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return nil, fmt.Errorf("unable to parse capability for protocol: %s", line.Name)
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}
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line.ModuleName = fields[7]
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err = line.Capabilities.parseCapabilities(fields[8:])
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if err != nil {
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return nil, err
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}
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return line, nil
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}
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func (pc *NetProtocolCapabilities) parseCapabilities(capabilities []string) error {
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// The capabilities are all bools so we can loop over to map them
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capabilityFields := [...]*bool{
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&pc.Close,
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&pc.Connect,
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&pc.Disconnect,
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&pc.Accept,
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&pc.IoCtl,
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&pc.Init,
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&pc.Destroy,
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&pc.Shutdown,
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&pc.SetSockOpt,
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&pc.GetSockOpt,
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&pc.SendMsg,
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&pc.RecvMsg,
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&pc.SendPage,
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&pc.Bind,
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&pc.BacklogRcv,
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&pc.Hash,
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&pc.UnHash,
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&pc.GetPort,
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&pc.EnterMemoryPressure,
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}
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for i := 0; i < len(capabilities); i++ {
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if capabilities[i] == "y" {
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*capabilityFields[i] = true
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} else if capabilities[i] == "n" {
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*capabilityFields[i] = false
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} else {
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return fmt.Errorf("unable to parse capability block for protocol: position %d", i)
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}
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}
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return nil
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}

‎net_protocols_test.go

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// Copyright 2020 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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import (
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"strings"
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"testing"
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)
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func TestParseCapabilities(t *testing.T) {
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rawStr := "y y y y y y y y y y y y y n y y y y y\n"
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have := NetProtocolCapabilities{}
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err := have.parseCapabilities(strings.Fields(rawStr))
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if err != nil {
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t.Fatal(err)
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}
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want := NetProtocolCapabilities{true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, true, true, true, true}
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if want != have {
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t.Errorf("want %+v\nhave %+v\n", want, have)
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}
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}
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func TestProtocolsParseLine(t *testing.T) {
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rawStr := "TCP 1984 93064 1225378 no 320 yes kernel y y y y y y y y y y y y y n y y y y y\n"
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protocols := NetProtocolStats{}
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have, err := protocols.parseLine(rawStr)
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if err != nil {
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t.Fatal(err)
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}
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want := NetProtocolStatLine{"TCP", 1984, 93064, 1225378, 0, 320, true, "kernel", NetProtocolCapabilities{true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, true, true, true, true}}
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if want != *have {
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t.Errorf("want %+v\nhave %+v\n", want, have)
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}
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}
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func TestProtocolsParseProtocols(t *testing.T) {
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fs, err := NewFS(procTestFixtures)
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if err != nil {
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t.Fatal(err)
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}
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protocolStats, err := fs.NetProtocols()
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if err != nil {
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t.Fatal(err)
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}
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lines := map[string]NetProtocolStatLine{
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"PACKET": {"PACKET", 1344, 2, -1, -1, 0, false, "kernel", NetProtocolCapabilities{false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false}},
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"PINGv6": {"PINGv6", 1112, 0, -1, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, false, true, false, false, true, true, true, true, false, true, true, true, true, true, false}},
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"RAWv6": {"RAWv6", 1112, 1, -1, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, false, true, true, true, true, false, false}},
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"UDPLITEv6": {"UDPLITEv6", 1216, 0, 57, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, false, false, false, true, true, true, false}},
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"UDPv6": {"UDPv6", 1216, 10, 57, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, false, false, false, true, true, true, false}},
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"TCPv6": {"TCPv6", 2144, 1937, 1225378, 0, 320, true, "kernel", NetProtocolCapabilities{true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, true, true, true, true}},
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"UNIX": {"UNIX", 1024, 120, -1, -1, 0, true, "kernel", NetProtocolCapabilities{false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false}},
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"UDP-Lite": {"UDP-Lite", 1024, 0, 57, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, true, false, false, true, true, true, false}},
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"PING": {"PING", 904, 0, -1, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, false, true, false, false, true, true, true, true, false, true, true, true, true, true, false}},
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"RAW": {"RAW", 912, 0, -1, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, false, true, true, true, true, false, false}},
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"UDP": {"UDP", 1024, 73, 57, -1, 0, true, "kernel", NetProtocolCapabilities{true, true, true, false, true, true, true, false, true, true, true, true, true, false, false, true, true, true, false}},
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"TCP": {"TCP", 1984, 93064, 1225378, 1, 320, true, "kernel", NetProtocolCapabilities{true, true, true, true, true, true, true, true, true, true, true, true, true, false, true, true, true, true, true}},
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"NETLINK": {"NETLINK", 1040, 16, -1, -1, 0, false, "kernel", NetProtocolCapabilities{false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false}},
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}
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if want, have := len(lines), len(protocolStats); want != have {
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t.Errorf("want %d parsed net/protocols lines, have %d", want, have)
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}
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for _, line := range protocolStats {
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if want, have := lines[line.Name], line; want != have {
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t.Errorf("%s: want %v, have %v", line.Name, want, have)
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}
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}
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}

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