/
arpcache.go
85 lines (68 loc) · 1.76 KB
/
arpcache.go
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// +build linux
// Copyright 2016-2019 DutchSec (https://dutchsec.com/)
//
// 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.
package canary
import (
"bufio"
"net"
"os"
)
// ARPCache defines a slice of ARPEntrys.
type ARPCache []ARPEntry
// Get retrieves the ARPEntry associated with the giving ip.
func (ac ARPCache) Get(ip net.IP) *ARPEntry {
for _, a := range ac {
if !a.IP.Equal(ip) {
continue
}
return &a
}
return nil
}
// ARPEntry defines a type for containing address and interface detail.
type ARPEntry struct {
IP net.IP
HardwareAddress net.HardwareAddr
Interface string
}
func parseARPCache(path string) (ARPCache, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
entries := []ARPEntry{}
r := bufio.NewReader(f)
// skip first line
r.ReadLine()
scanner := bufio.NewScanner(r)
for scanner.Scan() {
text := scanner.Text()
parts := splitAtBytes(text, " \r\t\n")
if len(parts) < 6 {
continue
}
ip := net.ParseIP(parts[0])
hwaddress, _ := net.ParseMAC(parts[3])
entries = append(entries, ARPEntry{
Interface: parts[5],
IP: ip,
HardwareAddress: hwaddress,
})
}
if err := scanner.Err(); err != nil {
return nil, err
}
return ARPCache(entries), nil
}