/usr/sbin/maas-dhcp-helper is in maas-rack-controller 2.4.0~beta2-6865-gec43e47e6-0ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | #! /usr/bin/python3
# -*- mode: python -*-
# Copyright 2016 Canonical Ltd. This software is licensed under the
# GNU Affero General Public License version 3 (see the file LICENSE).
"""Utility script used by maas-dhcpd and maas-dhcpd6.
`notify` is called by maas-dhcpd and maas-dhcpd6 with the on execute command
from isc-dhcp-server when a lease is committed, released, or expired. Sends
a JSON encoded message over the `dhcpd.sock` to the running rackd process.
`clean` is called by maas-dhcpd and maas-dhcpd6 when either service starts
to remove any host entries from the passed leases file. This is used to make
sure that when maas-dhcpd and maas-dhcpd6 start that only the host entries
from the dhcpd.conf or dhcpd6.conf are used.
"""
import argparse
def notify_add_arguments(parser):
"""Initialise options for sending DHCP notification over the dhcpd.sock.
:param parser: An instance of :class:`ArgumentParser`.
"""
parser.add_argument(
"--action", action="store", required=True,
choices=['commit', 'expiry', 'release'], help=(
"Action taken by DHCP server for the lease."))
parser.add_argument(
"--mac", action="store", required=True, help=(
"MAC address for lease."))
parser.add_argument(
"--ip-family", action="store", required=True, choices=['ipv4', 'ipv6'],
help="IP address family for lease.")
parser.add_argument(
"--ip", action="store", required=True, help=(
"IP address for lease."))
parser.add_argument(
"--lease-time", action="store", type=int, required=False, help=(
"Length of time before the lease expires."))
parser.add_argument(
"--hostname", action="store", required=False, help=(
"Hostname of the machine for the lease."))
parser.add_argument(
"--socket", action="store", required=False,
default="/var/lib/maas/dhcpd.sock", help=argparse.SUPPRESS)
def notify(args):
"""Write DHCP action notification to the `dhcpd.sock`."""
# Perform the imports for this command. This speeds up the operation of
# each command.
from contextlib import closing
import json
import socket
import time
notify_packet = {
"action": args.action,
"mac": args.mac,
"ip_family": args.ip_family,
"ip": args.ip,
"timestamp": int(time.time()),
}
# Lease time is required by the commit action and hostname is optional.
if args.action == "commit":
notify_packet["lease_time"] = args.lease_time
hostname = args.hostname
has_hostname = (
hostname is not None and
len(hostname) > 0 and
not hostname.isspace())
if has_hostname:
notify_packet["hostname"] = hostname
# Connect to the socket and send the packet over as JSON.
payload = json.dumps(notify_packet)
conn = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
conn.connect(args.socket)
with closing(conn):
conn.send(payload.encode("utf-8"))
def clean_add_arguments(parser):
"""Initialise options for cleaning the dhcpd.leases file.
:param parser: An instance of :class:`ArgumentParser`.
"""
parser.add_argument(
"leases_file", action="store",
help=("Leases file to remove host entries from."))
def clean(args):
"""Remove all host entries from leases file."""
# Perform the imports for this command. This speeds up the operation of
# each command.
import re
with open(args.leases_file, "r", encoding="utf-8") as fp:
content = fp.read()
cleaned_content = re.sub("host [^{]+{[^}]+}\n", "", content)
with open(args.leases_file, "w", encoding="utf-8") as fp:
fp.write(cleaned_content)
def main():
"""Main entry point for the script."""
parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers(title="command")
subparsers.required = True
subparsers.dest = "command"
# Notify.
notify_parser = subparsers.add_parser(
"notify", help="Write DHCP action notification to the `dhcpd.sock`.")
notify_parser.set_defaults(handler=notify)
notify_add_arguments(notify_parser)
# Clean.
clean_parser = subparsers.add_parser(
"clean", help="Remove all host entries from leases file.")
clean_parser.set_defaults(handler=clean)
clean_add_arguments(clean_parser)
# Run the parser and the command.
args = parser.parse_args()
args.handler(args)
if __name__ == "__main__":
main()
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