node_exporter/collector/arp_linux.go

170 lines
4.5 KiB
Go

// Copyright 2017 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build !noarp
// +build !noarp
package collector
import (
"fmt"
"log/slog"
"github.com/alecthomas/kingpin/v2"
"github.com/jsimonetti/rtnetlink/v2/rtnl"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/procfs"
"golang.org/x/sys/unix"
)
var (
arpDeviceInclude = kingpin.Flag("collector.arp.device-include", "Regexp of arp devices to include (mutually exclusive to device-exclude).").String()
arpDeviceExclude = kingpin.Flag("collector.arp.device-exclude", "Regexp of arp devices to exclude (mutually exclusive to device-include).").String()
arpNetlink = kingpin.Flag("collector.arp.netlink", "Use netlink to gather stats instead of /proc/net/arp.").Default("true").Bool()
)
type arpCollector struct {
fs procfs.FS
deviceFilter deviceFilter
entries *prometheus.Desc
states *prometheus.Desc
logger *slog.Logger
}
var neighborStatesMap = map[uint16]string{
unix.NUD_INCOMPLETE: "incomplete",
unix.NUD_REACHABLE: "reachable",
unix.NUD_STALE: "stale",
unix.NUD_DELAY: "delay",
unix.NUD_PROBE: "probe",
unix.NUD_FAILED: "failed",
unix.NUD_PERMANENT: "permanent",
}
func init() {
registerCollector("arp", defaultEnabled, NewARPCollector)
}
// NewARPCollector returns a new Collector exposing ARP stats.
func NewARPCollector(logger *slog.Logger) (Collector, error) {
fs, err := procfs.NewFS(*procPath)
if err != nil {
return nil, fmt.Errorf("failed to open procfs: %w", err)
}
return &arpCollector{
fs: fs,
deviceFilter: newDeviceFilter(*arpDeviceExclude, *arpDeviceInclude),
entries: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "arp", "entries"),
"ARP entries by device",
[]string{"device"}, nil,
),
states: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "arp", "states"),
"ARP states by device",
[]string{"device", "state"}, nil,
),
logger: logger,
}, nil
}
func getTotalArpEntries(deviceEntries []procfs.ARPEntry) map[string]uint32 {
entries := make(map[string]uint32)
for _, device := range deviceEntries {
entries[device.Device]++
}
return entries
}
func getArpEntriesRTNL() (map[string]uint32, map[string]map[string]int, error) {
conn, err := rtnl.Dial(nil)
if err != nil {
return nil, nil, err
}
defer conn.Close()
// Neighbors will also contain IPv6 neighbors, but since this is purely an ARP collector,
// restrict to AF_INET.
neighbors, err := conn.Neighbours(nil, unix.AF_INET)
if err != nil {
return nil, nil, err
}
// Map of interface name to ARP neighbor count.
entries := make(map[string]uint32)
// Map of map[InterfaceName]map[StateName]int
states := make(map[string]map[string]int)
for _, n := range neighbors {
// Skip entries which have state NUD_NOARP to conform to output of /proc/net/arp.
if n.State&unix.NUD_NOARP == unix.NUD_NOARP {
continue
}
entries[n.Interface.Name]++
_, ok := states[n.Interface.Name]
if !ok {
states[n.Interface.Name] = make(map[string]int)
}
states[n.Interface.Name][neighborStatesMap[n.State]]++
}
return entries, states, nil
}
func (c *arpCollector) Update(ch chan<- prometheus.Metric) error {
var (
enumeratedEntry map[string]uint32
enumStates map[string]map[string]int
)
if *arpNetlink {
var err error
enumeratedEntry, enumStates, err = getArpEntriesRTNL()
if err != nil {
return fmt.Errorf("could not get ARP entries: %w", err)
}
} else {
entries, err := c.fs.GatherARPEntries()
if err != nil {
return fmt.Errorf("could not get ARP entries: %w", err)
}
enumeratedEntry = getTotalArpEntries(entries)
}
for device, entryCount := range enumeratedEntry {
if c.deviceFilter.ignored(device) {
continue
}
ch <- prometheus.MustNewConstMetric(
c.entries, prometheus.GaugeValue, float64(entryCount), device)
if *arpNetlink {
states := enumStates[device]
for state, count := range states {
ch <- prometheus.MustNewConstMetric(
c.states, prometheus.GaugeValue, float64(count), device, state)
}
}
}
return nil
}