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#!/usr/bin/env python3
#
# Copyright VyOS maintainers and contributors <maintainers@vyos.io>
#
# 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 os
import re
import time
import logging
import logging.handlers
from pathlib import Path
from sys import argv
from vyos.defaults import directories
from vyos.utils.process import cmdl
from vyos.utils.boot import boot_configuration_complete
from vyos.utils.locking import Lock
# Define variables
vyos_udev_dir = directories['vyos_udev_dir']
# NOTE: this script only picks a provisional name for a physical interface
# as it is discovered by udev - it is a best-effort placeholder and does
# NOT look at 'hw-id' in config.boot. The authoritative, hw-id based name
# (if one is configured) is applied afterwards, once, by
# vyos-net-name-resolve.py (src/system/vyos-net-name-resolve.py), which
# runs after all hardware has settled. Deciding hw-id names here, from a
# single per-uevent sysfs snapshot, is what caused interface names to be
# unreliable on systems with multiple NIC vendors/drivers: the DRIVERS
# attribute and the interface's permanent MAC address are not guaranteed
# to be populated yet at the moment a single "add" uevent is evaluated,
# and there is no second chance to re-evaluate it.
def is_available(intfs: dict, intf_name: str) -> bool:
"""Check if interface name is already assigned"""
if intf_name in list(intfs.values()):
return False
return True
def find_available(intfs: dict, prefix: str) -> str:
"""Find lowest indexed interface name that is not assigned"""
index_list = []
for x in intfs.values():
if not x.startswith(prefix):
continue
suffix = x[len(prefix):]
if suffix.isdigit():
index_list.append(int(suffix))
if not index_list:
return f'{prefix}0'
index_list.sort()
# find 'holes' in list, if any
missing = sorted(set(range(index_list[0], index_list[-1])) - set(index_list))
if missing:
return f'{prefix}{missing[0]}'
return f'{prefix}{index_list[-1] + 1}'
def mod_ifname(ifname: str) -> str:
"""Check interface with names eX and return ifname on the next format eth{ifindex} - 2"""
if re.match('^e[0-9]+$', ifname):
intf = ifname.split('e')
if intf[1]:
if int(intf[1]) >= 2:
return 'eth' + str(int(intf[1]) - 2)
else:
return 'eth' + str(intf[1])
return ifname
def get_biosdevname(ifname: str) -> str:
"""Use legacy vyatta-biosdevname to query for name
This is carried over for compatibility only, and will likely be dropped
going forward.
XXX: This throws an error, and likely has for a long time, unnoticed
since vyatta_net_name redirected stderr to /dev/null.
"""
intf = mod_ifname(ifname)
if 'eth' not in intf:
return intf
if os.path.isdir('/proc/xen'):
return intf
time.sleep(1)
try:
biosname = cmdl(['/sbin/biosdevname', '--policy', 'all_ethN', '-i', ifname])
except Exception as e:
# expected/harmless on most virtualized and some bare-metal
# systems - see the XXX above; the caller already falls back to
# mod_ifname()'s guess, so this isn't worth more than a debug note
logger.debug(f'biosdevname unavailable for {ifname}: {e}')
biosname = ''
return intf if biosname == '' else biosname
def leave_rescan_hint(intf_name: str, hwid: str):
"""Write interface information reported by udev
This script is called while the root mount is still read-only. Leave
information in /run/udev: file name, the interface; contents, the
hardware id.
"""
try:
os.mkdir(vyos_udev_dir)
except FileExistsError:
pass
except Exception as e:
logger.critical(f'Error creating rescan hint directory: {e}')
exit(1)
try:
with open(os.path.join(vyos_udev_dir, intf_name), 'w') as f:
f.write(hwid)
except OSError as e:
logger.critical(f'OSError {e}')
def add_assigned_interfaces(intfs: dict):
"""Add interfaces found by previous invocation of udev rule"""
if not os.path.isdir(vyos_udev_dir):
return
for intf in os.listdir(vyos_udev_dir):
path = os.path.join(vyos_udev_dir, intf)
try:
with open(path) as f:
hwid = f.read().rstrip()
except OSError as e:
logger.error(f'OSError {e}')
continue
intfs[hwid] = intf
def on_boot_event(intf_name: str, hwid: str, predefined: str = '') -> str:
"""Called on boot by vyos-router: 'coldplug' in vyatta_net_name
Picks a provisional name only - see the module docstring. hw-id from
config.boot is deliberately NOT consulted here.
"""
interfaces: dict = {}
add_assigned_interfaces(interfaces)
logger.debug(f'{intf_name} ({hwid}): already assigned this boot: {interfaces}')
if predefined:
newname = predefined
else:
newname = get_biosdevname(intf_name)
if not is_available(interfaces, newname):
prefix = re.sub(r'\d+$', '', newname)
newname = find_available(interfaces, prefix)
logger.info(f"{intf_name} ({hwid}) -> '{newname}'")
leave_rescan_hint(newname, hwid)
return newname
def hotplug_event():
# Not yet implemented, since interface-rescan will only be run on boot.
pass
if __name__ == '__main__':
# Set up logging to syslog
syslog_handler = logging.handlers.SysLogHandler(address='/dev/log')
formatter = logging.Formatter(f'{Path(__file__).name}: %(message)s')
syslog_handler.setFormatter(formatter)
logger = logging.getLogger()
logger.addHandler(syslog_handler)
logger.setLevel(logging.INFO)
logger.debug(f'started with arguments: {argv}')
if len(argv) > 3:
predef_name = argv[3]
else:
predef_name = ''
lock = Lock('vyos_net_name')
# Wait 60 seconds for other running scripts to finish
lock.acquire(60)
if not boot_configuration_complete():
print(on_boot_event(argv[1], argv[2], predefined=predef_name))
lock.release()
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