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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
#!/usr/bin/env python3
#
# Copyright (C) 2023 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import logging
from concurrent.futures import ProcessPoolExecutor
from pathlib import Path
from subprocess import run, TimeoutExpired
from sys import exit
from psutil import net_if_addrs, AF_LINK
from systemd.journal import JournalHandler
from yaml import safe_load
from vyos.template import render
# define a path to the configuration file and template
config_file = '/etc/cloud/cloud.cfg.d/20_vyos_network.cfg'
template_file = 'system/cloud_init_networking.j2'
def check_interface_dhcp(iface_name: str) -> bool:
"""Check DHCP client can work on an interface
Args:
iface_name (str): interface name
Returns:
bool: check result
"""
dhclient_command: list[str] = [
'dhclient', '-4', '-1', '-q', '--no-pid', '-sf', '/bin/true', iface_name
]
check_result = False
# try to get an IP address
# we use dhclient behavior here to speedup detection
# if dhclient receives a configuration and configure an interface
# it switch to background
# If no - it will keep running in foreground
try:
run(['ip', 'l', 'set', iface_name, 'up'])
run(dhclient_command, timeout=5)
check_result = True
except TimeoutExpired:
pass
finally:
run(['ip', 'l', 'set', iface_name, 'down'])
logger.info(f'DHCP server was found on {iface_name}: {check_result}')
return check_result
def dhclient_cleanup() -> None:
"""Clean up after dhclients
"""
run(['killall', 'dhclient'])
leases_file: Path = Path('/var/lib/dhcp/dhclient.leases')
leases_file.unlink(missing_ok=True)
logger.debug('cleaned up after dhclients')
def dict_interfaces() -> dict[str, str]:
"""Return list of available network interfaces except loopback
Returns:
list[str]: a list of interfaces
"""
interfaces_dict: dict[str, str] = {}
ifaces = net_if_addrs()
for iface_name, iface_addresses in ifaces.items():
# we do not need loopback interface
if iface_name == 'lo':
continue
# check other interfaces for MAC addresses
for iface_addr in iface_addresses:
if iface_addr.family == AF_LINK and iface_addr.address:
interfaces_dict[iface_name] = iface_addr.address
continue
logger.debug(f'found interfaces: {interfaces_dict}')
return interfaces_dict
def need_to_check() -> bool:
"""Check if we need to perform DHCP checks
Returns:
bool: check result
"""
# if cloud-init config does not exist, we do not need to do anything
ci_config_vyos = Path('/etc/cloud/cloud.cfg.d/20_vyos_custom.cfg')
if not ci_config_vyos.exists():
logger.info(
'No need to check interfaces: Cloud-init config file was not found')
return False
# load configuration file
try:
config = safe_load(ci_config_vyos.read_text())
except:
logger.error('Cloud-init config file has a wrong format')
return False
# check if we have in config configured option
# vyos_config_options:
# network_preconfigure: true
if not config.get('vyos_config_options', {}).get('network_preconfigure'):
logger.info(
'No need to check interfaces: Cloud-init config option "network_preconfigure" is not set'
)
return False
return True
if __name__ == '__main__':
# prepare logger
logger = logging.getLogger(__name__)
logger.addHandler(JournalHandler(SYSLOG_IDENTIFIER=Path(__file__).name))
logger.setLevel(logging.INFO)
# we need to give udev some time to rename all interfaces
# this is placed before need_to_check() call, because we are not always
# need to preconfigure cloud-init, but udev always need to finish its work
# before cloud-init start
run(['udevadm', 'settle'])
logger.info('udev finished its work, we continue')
# do not perform any checks if this is not required
if not need_to_check():
exit()
# get list of interfaces and check them
interfaces_dhcp: list[dict[str, str]] = []
interfaces_dict: dict[str, str] = dict_interfaces()
with ProcessPoolExecutor(max_workers=len(interfaces_dict)) as executor:
iface_check_results = [{
'dhcp': executor.submit(check_interface_dhcp, iface_name),
'append': {
'name': iface_name,
'mac': iface_mac
}
} for iface_name, iface_mac in interfaces_dict.items()]
dhclient_cleanup()
for iface_check_result in iface_check_results:
if iface_check_result.get('dhcp').result():
interfaces_dhcp.append(iface_check_result.get('append'))
# render cloud-init config
if interfaces_dhcp:
logger.debug('rendering cloud-init network configuration')
render(config_file, template_file, {'ifaces_list': interfaces_dhcp})
exit()
|
