111 lines
2.5 KiB
Go
111 lines
2.5 KiB
Go
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/*
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Copyright 2016 The Kubernetes Authors All rights reserved.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package hyperkit
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"regexp"
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"strings"
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)
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const (
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DHCPLeasesFile = "/var/db/dhcpd_leases"
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)
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type DHCPEntry struct {
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Name string
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IPAddress string
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HWAddress string
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ID string
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Lease string
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}
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func GetIPAddressByMACAddress(mac string) (string, error) {
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return getIpAddressFromFile(mac, DHCPLeasesFile)
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}
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func getIpAddressFromFile(mac, path string) (string, error) {
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file, err := os.Open(path)
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if err != nil {
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return "", err
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}
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defer file.Close()
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dhcpEntries, err := parseDHCPdLeasesFile(file)
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if err != nil {
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return "", err
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}
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for _, dhcpEntry := range dhcpEntries {
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if dhcpEntry.HWAddress == mac {
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return dhcpEntry.IPAddress, nil
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}
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}
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return "", fmt.Errorf("Could not find an IP address for %s", mac)
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}
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func parseDHCPdLeasesFile(file io.Reader) ([]DHCPEntry, error) {
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var (
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dhcpEntry *DHCPEntry
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dhcpEntries []DHCPEntry
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)
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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line := strings.TrimSpace(scanner.Text())
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if line == "{" {
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dhcpEntry = new(DHCPEntry)
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continue
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} else if line == "}" {
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dhcpEntries = append(dhcpEntries, *dhcpEntry)
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continue
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}
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split := strings.SplitN(line, "=", 2)
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if len(split) != 2 {
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return nil, fmt.Errorf("invalid line in dhcp leases file: %s", line)
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}
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key, val := split[0], split[1]
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switch key {
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case "name":
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dhcpEntry.Name = val
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case "ip_address":
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dhcpEntry.IPAddress = val
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case "hw_address":
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// The mac addresses have a '1,' at the start.
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dhcpEntry.HWAddress = val[2:]
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case "identifier":
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dhcpEntry.ID = val
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case "lease":
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dhcpEntry.Lease = val
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default:
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return dhcpEntries, fmt.Errorf("Unable to parse line: %s", line)
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}
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}
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return dhcpEntries, scanner.Err()
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}
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// trimMacAddress trimming "0" of the ten's digit
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func trimMacAddress(rawUUID string) string {
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re := regexp.MustCompile(`0([A-Fa-f0-9](:|$))`)
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mac := re.ReplaceAllString(rawUUID, "$1")
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return mac
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}
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