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package network
import (
"fmt"
"strings"
"sync"
"github.com/bettercap/bettercap/core"
)
type ArpTable map[string]string
var (
arpWasParsed = false
arpLock = &sync.RWMutex{}
arpTable = make(ArpTable)
)
func ArpUpdate(iface string) (ArpTable, error) {
arpLock.Lock()
defer arpLock.Unlock()
// Signal we parsed the ARP table at least once.
arpWasParsed = true
// Run "arp -an" (darwin) or "ip neigh" (linux) and parse the output
output, err := core.Exec(ArpCmd, ArpCmdOpts)
if err != nil {
return arpTable, err
}
newTable := make(ArpTable)
for _, line := range strings.Split(output, "\n") {
m := ArpTableParser.FindStringSubmatch(line)
if len(m) == ArpTableTokens {
ipIndex := ArpTableTokenIndex[0]
hwIndex := ArpTableTokenIndex[1]
ifIndex := ArpTableTokenIndex[2]
address := m[ipIndex]
mac := m[hwIndex]
ifname := iface
if ifIndex != -1 {
ifname = m[ifIndex]
}
if ifname == iface {
newTable[address] = mac
}
}
}
arpTable = newTable
return arpTable, nil
}
func ArpLookup(iface string, address string, refresh bool) (string, error) {
// Refresh ARP table if first run or if a force refresh has been instructed.
if !ArpParsed() || refresh {
if _, err := ArpUpdate(iface); err != nil {
return "", err
}
}
arpLock.RLock()
defer arpLock.RUnlock()
// Lookup the hardware address of this ip.
if mac, found := arpTable[address]; found {
return mac, nil
}
return "", fmt.Errorf("Could not find mac for %s", address)
}
func ArpInverseLookup(iface string, mac string, refresh bool) (string, error) {
if !ArpParsed() || refresh {
if _, err := ArpUpdate(iface); err != nil {
return "", err
}
}
arpLock.RLock()
defer arpLock.RUnlock()
for ip, hw := range arpTable {
if hw == mac {
return ip, nil
}
}
return "", fmt.Errorf("Could not find IP for %s", mac)
}
func ArpParsed() bool {
arpLock.RLock()
defer arpLock.RUnlock()
return arpWasParsed
}
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