interface-names: T3869: add vyos_net_name

1 files changed, 229 insertions, 0 deletions

diff --git a/src/helpers/vyos_net_name b/src/helpers/vyos_net_name
new file mode 100755
index 000000000..0652e98b1
--- /dev/null
+++ b/src/helpers/vyos_net_name
@@ -0,0 +1,229 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 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 os
+import re
+import time
+import logging
+import threading
+from sys import argv
+
+from vyos.configtree import ConfigTree
+from vyos.defaults import directories
+from vyos.util import cmd
+
+vyos_udev_dir = directories['vyos_udev_dir']
+vyos_log_dir = '/run/udev/log'
+vyos_log_file = os.path.join(vyos_log_dir, 'vyos-net-name')
+
+config_path = '/opt/vyatta/etc/config/config.boot'
+config_status = '/tmp/vyos-config-status'
+
+lock = threading.Lock()
+
+try:
+    os.mkdir(vyos_log_dir)
+except FileExistsError:
+    pass
+
+logging.basicConfig(filename=vyos_log_file, level=logging.DEBUG)
+
+def boot_configuration_complete() -> bool:
+    """ Check if vyos-router has completed, hence hotplug event
+    """
+    if os.path.isfile(config_status):
+        return True
+    return False
+
+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 iterface name that is not assigned
+    """
+    index_list = [int(x.replace(prefix, '')) for x in list(intfs.values()) if prefix in x]
+    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}{len(index_list)}'
+
+def get_biosdevname(ifname: str) -> str:
+    """ Use legacy vyatta-biosdevname to query for name
+
+    This is carried over for compatability 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.
+    """
+    if 'eth' not in ifname:
+        return ifname
+    if os.path.isdir('/proc/xen'):
+        return ifname
+
+    time.sleep(1)
+
+    try:
+        biosname = cmd(f'/sbin/biosdevname --policy all_ethN -i {ifname}')
+    except Exception as e:
+        logging.error(f'biosdevname error: {e}')
+        biosname = ''
+
+    return ifname 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:
+        logging.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:
+        logging.critical(f"OSError {e}")
+
+def get_configfile_interfaces() -> dict:
+    """Read existing interfaces from config file
+    """
+    interfaces: dict = {}
+
+    if not os.path.isfile(config_path):
+        # If the case, then we are running off of livecd; return empty
+        return interfaces
+
+    try:
+        with open(config_path) as f:
+            config_file = f.read()
+    except OSError as e:
+        logging.critical(f"OSError {e}")
+        exit(1)
+
+    config = ConfigTree(config_file)
+
+    base = ['interfaces', 'ethernet']
+    if config.exists(base):
+        eth_intfs = config.list_nodes(base)
+        for intf in eth_intfs:
+            path = base + [intf, 'hw-id']
+            if not config.exists(path):
+                logging.warning(f"no 'hw-id' entry for {intf}")
+                continue
+            hwid = config.return_value(path)
+            if hwid in list(interfaces):
+                logging.warning(f"multiple entries for {hwid}: {interfaces[hwid]}, {intf}")
+                continue
+            interfaces[hwid] = intf
+
+    base = ['interfaces', 'wireless']
+    if config.exists(base):
+        wlan_intfs = config.list_nodes(base)
+        for intf in wlan_intfs:
+            path = base + [intf, 'hw-id']
+            if not config.exists(path):
+                logging.warning(f"no 'hw-id' entry for {intf}")
+                continue
+            hwid = config.return_value(path)
+            if hwid in list(interfaces):
+                logging.warning(f"multiple entries for {hwid}: {interfaces[hwid]}, {intf}")
+                continue
+            interfaces[hwid] = intf
+
+    logging.debug(f"config file entries: {interfaces}")
+
+    return interfaces
+
+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:
+            logging.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
+    """
+    logging.info(f"lookup {intf_name}, {hwid}")
+    interfaces = get_configfile_interfaces()
+    logging.debug(f"config file interfaces are {interfaces}")
+
+    if hwid in list(interfaces) and intf_name == interfaces[hwid]:
+        logging.info(f"use mapping from config file: '{hwid}' -> '{intf_name}'")
+        return intf_name
+
+    add_assigned_interfaces(interfaces)
+    logging.debug(f"adding assigned interfaces: {interfaces}")
+
+    if predefined:
+        newname = predefined
+        logging.info(f"predefined interface name for '{intf_name}' is '{newname}'")
+    else:
+        newname = get_biosdevname(intf_name)
+        logging.info(f"biosdevname returned '{newname}' for '{intf_name}'")
+
+    if not is_available(interfaces, newname):
+        prefix = re.sub(r'\d+$', '', newname)
+        newname = find_available(interfaces, prefix)
+
+    logging.info(f"new name for '{intf_name}' is '{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 len(argv) > 3:
+    predef_name = argv[3]
+else:
+    predef_name = ''
+
+lock.acquire()
+if not boot_configuration_complete():
+    res = on_boot_event(argv[1], argv[2], predefined=predef_name)
+    logging.debug(f"on boot, returned name is {res}")
+else:
+    logging.debug("boot configuration complete")
+lock.release()
+