64 lines
1.2 KiB
Go
64 lines
1.2 KiB
Go
package arp
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import (
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"net"
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"sync"
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"time"
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"github.com/sirupsen/logrus"
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)
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func init() {
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go func() {
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t := time.NewTicker(time.Second * 5)
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for {
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refresh()
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<-t.C
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}
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}()
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}
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var table sync.Map
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func refresh() {
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t, err := lookup()
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if err != nil {
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logrus.StandardLogger().WithError(err).Warn("arp cache refresh failed")
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} else {
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for k, v := range t {
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logrus.StandardLogger().WithFields(logrus.Fields{
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"mac": v,
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"ip": k,
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}).Debug("Updating ARP cache")
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table.Store(k, v)
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}
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}
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}
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func Get(addr net.Addr) net.HardwareAddr {
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if addr == nil {
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logrus.StandardLogger().Trace("No address found, can't lookup IP for MAC")
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return nil
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}
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var ip net.IP
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switch addr := addr.(type) {
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case *net.TCPAddr:
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ip = addr.IP
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case *net.UDPAddr:
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ip = addr.IP
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}
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if ip == nil {
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logrus.StandardLogger().WithField("addr", addr.String()).Trace("No IP address found, can't lookup MAC")
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return nil
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}
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if v, ok := table.Load(ip.String()); ok {
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logrus.StandardLogger().WithField("ip", ip.String()).Tracef("%s is at %s", ip, v.(net.HardwareAddr).String())
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return v.(net.HardwareAddr)
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}
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logrus.StandardLogger().WithField("ip", ip.String()).Trace("No MAC address found")
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return nil
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}
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