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Merge branch 'scanner' into 'master'

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usable cdist scan

See merge request ungleich-public/cdist!993
This commit is contained in:
fnux 2021-07-05 07:44:28 +02:00
commit 44eeb4bbfc
6 changed files with 342 additions and 122 deletions
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24
cdist/argparse.py
View file

@ -485,19 +485,31 @@ def get_parsers():
parser['scan'].add_argument(
'-m', '--mode', help='Which modes should run',
action='append', default=[],
choices=['scan', 'trigger'])
choices=['scan', 'trigger', 'config'])
parser['scan'].add_argument(
'--list',
action='store_true',
help='List the known hosts and exit')
parser['scan'].add_argument(
'--config',
action='store_true',
help='Try to configure detected hosts')
parser['scan'].add_argument(
'-I', '--interfaces',
action='append', default=[],
'-I', '--interface',
action='append', default=[], required=True,
help='On which interfaces to scan/trigger')
parser['scan'].add_argument(
'-d', '--delay',
action='store', default=3600,
help='How long to wait before reconfiguring after last try')
'--name-mapper',
action='store', default=None,
help='Map addresses to names, required for config mode')
parser['scan'].add_argument(
'-d', '--config-delay',
action='store', default=3600, type=int,
help='How long (seconds) to wait before reconfiguring after last try')
parser['scan'].add_argument(
'-t', '--trigger-delay',
action='store', default=5, type=int,
help='How long (seconds) to wait between ICMPv6 echo requests')
parser['scan'].set_defaults(func=cdist.scan.commandline.commandline)
for p in parser:

92
cdist/scan/commandline.py
View file

@ -20,36 +20,98 @@
#
import logging
import sys
from datetime import datetime
log = logging.getLogger("scan")
# define this outside of the class to not handle scapy import errors by default
def commandline(args):
log.debug(args)
try:
import cdist.scan.scan as scan
except ModuleNotFoundError:
print('cdist scan requires scapy to be installed')
def run(scan, args):
# We run each component in a separate process since they
# must not block on each other.
processes = []
if not args.mode:
# By default scan and trigger, but do not call any action
args.mode = ['scan', 'trigger', ]
if 'trigger' in args.mode:
t = scan.Trigger(interfaces=args.interfaces)
t = scan.Trigger(interfaces=args.interface,
sleeptime=args.trigger_delay)
t.start()
processes.append(t)
log.debug("Trigger started")
if 'scan' in args.mode:
s = scan.Scanner(interfaces=args.interfaces, args=args)
s = scan.Scanner(
autoconfigure='config' in args.mode,
interfaces=args.interface,
name_mapper=args.name_mapper)
s.start()
processes.append(s)
log.debug("Scanner started")
for process in processes:
process.join()
def list(scan, args):
s = scan.Scanner(interfaces=args.interface, name_mapper=args.name_mapper)
hosts = s.list()
# A full IPv6 addresses id composed of 8 blocks of 4 hexa chars +
# 6 colons.
ipv6_max_size = 8 * 4 + 10
date_max_size = len(datetime.now().strftime(scan.datetime_format))
name_max_size = 25
print("{} | {} | {} | {}".format(
'name'.ljust(name_max_size),
'address'.ljust(ipv6_max_size),
'last seen'.ljust(date_max_size),
'last configured'.ljust(date_max_size)))
print('=' * (name_max_size + 3 + ipv6_max_size + 2 * (3 + date_max_size)))
for host in hosts:
last_seen = host.last_seen()
if last_seen:
last_seen = last_seen.strftime(scan.datetime_format)
else:
last_seen = '-'
last_configured = host.last_configured()
if last_configured is not None:
last_configured = last_configured.strftime(scan.datetime_format)
else:
last_configured = '-'
print("{} | {} | {} | {}".format(
host.name(default='-').ljust(name_max_size),
host.address().ljust(ipv6_max_size),
last_seen.ljust(date_max_size),
last_configured.ljust(date_max_size)))
# CLI processing is defined outside of the main scan class to handle
# non-available optional scapy dependency (instead of crashing mid-flight).
def commandline(args):
log.debug(args)
# Check if we have the optional scapy dependency available.
try:
import cdist.scan.scan as scan
except ModuleNotFoundError:
log.error('cdist scan requires scapy to be installed. Exiting.')
sys.exit(1)
# Set default operation mode.
if not args.mode:
# By default scan and trigger, but do not call any action.
args.mode = ['scan', 'trigger', ]
if 'config' in args.mode and args.name_mapper is None:
print('--name-mapper must be specified for scanner config mode.',
file=sys.stderr)
sys.exit(1)
# Print known hosts and exit is --list is specified - do not start
# the scanner.
if args.list:
list(scan, args)
else:
run(scan, args)

237
cdist/scan/scan.py
View file

@ -19,38 +19,6 @@
#
#
#
# Interface to be implemented:
# - cdist scan --mode {scan, trigger, install, config}, --mode can be repeated
# scan: scan / listen for icmp6 replies
# trigger: send trigger to multicast
# config: configure newly detected hosts
# install: install newly detected hosts
#
# Scanner logic
# - save results to configdir:
# basedir = ~/.cdist/scan/<ipv6-address>
# last_seen = ~/.cdist/scan/<ipv6-address>/last_seen -- record unix time
# or similar
# last_configured = ~/.cdist/scan/<ipv6-address>/last_configured -- record
# unix time or similar
# last_installed = ~/.cdist/scan/<ipv6-address>/last_configured -- record
# unix time or similar
#
#
#
#
# cdist scan --list
# Show all known hosts including last seen flag
#
# Logic for reconfiguration:
#
# - record when configured last time
# - introduce a parameter --reconfigure-after that takes time argument
# - reconfigure if a) host alive and b) reconfigure-after time passed
#
from multiprocessing import Process
import os
import logging
@ -61,7 +29,84 @@ import datetime
import cdist.config
logging.basicConfig(level=logging.DEBUG)
log = logging.getLogger("scan")
datetime_format = '%Y-%m-%d %H:%M:%S'
class Host(object):
def __init__(self, addr, outdir, name_mapper=None):
self.addr = addr
self.workdir = os.path.join(outdir, addr)
self.name_mapper = name_mapper
os.makedirs(self.workdir, exist_ok=True)
def __get(self, key, default=None):
fname = os.path.join(self.workdir, key)
value = default
if os.path.isfile(fname):
with open(fname, "r") as fd:
value = fd.readline()
return value
def __set(self, key, value):
fname = os.path.join(self.workdir, key)
with open(fname, "w") as fd:
fd.write(f"{value}")
def name(self, default=None):
if self.name_mapper is None:
return default
fpath = os.path.join(os.getcwd(), self.name_mapper)
if os.path.isfile(fpath) and os.access(fpath, os.X_OK):
out = subprocess.run([fpath, self.addr], capture_output=True)
if out.returncode != 0:
return default
else:
value = out.stdout.decode()
return (default if len(value) == 0 else value)
else:
return default
def address(self):
return self.addr
def last_seen(self, default=None):
raw = self.__get('last_seen')
if raw:
return datetime.datetime.strptime(raw, datetime_format)
else:
return default
def last_configured(self, default=None):
raw = self.__get('last_configured')
if raw:
return datetime.datetime.strptime(raw, datetime_format)
else:
return default
def seen(self):
now = datetime.datetime.now().strftime(datetime_format)
self.__set('last_seen', now)
# XXX: There's no easy way to use the config module without feeding it with
# CLI args. Might as well call everything from scratch!
def configure(self):
target = self.name() or self.address()
cmd = ['cdist', 'config', '-v', target]
fname = os.path.join(self.workdir, 'last_configuration_log')
with open(fname, "w") as fd:
log.debug("Executing: %s", cmd)
completed_process = subprocess.run(cmd, stdout=fd, stderr=fd)
if completed_process.returncode != 0:
log.error("%s return with non-zero code %i - see %s for \
details.", cmd, completed_process.returncode, fname)
now = datetime.datetime.now().strftime(datetime_format)
self.__set('last_configured', now)
class Trigger(object):
@ -69,12 +114,14 @@ class Trigger(object):
Trigger an ICMPv6EchoReply from all hosts that are alive
"""
def __init__(self, interfaces=None, verbose=False):
def __init__(self, interfaces, sleeptime, verbose=False):
self.interfaces = interfaces
# Used by scapy / send in trigger/2.
self.verbose = verbose
# Wait 5 seconds before triggering again - FIXME: add parameter
self.sleeptime = 5
# Delay in seconds between sent ICMPv6EchoRequests.
self.sleeptime = sleeptime
def start(self):
self.processes = []
@ -93,9 +140,14 @@ class Trigger(object):
time.sleep(self.sleeptime)
def trigger(self, interface):
packet = IPv6(dst="ff02::1{}".format(interface)) / ICMPv6EchoRequest()
log.debug("Sending request on %s", interface)
send(packet, verbose=self.verbose)
try:
log.debug("Sending ICMPv6EchoRequest on %s", interface)
packet = IPv6(
dst="ff02::1%{}".format(interface)
) / ICMPv6EchoRequest()
send(packet, verbose=self.verbose)
except Exception as e:
log.error("Could not send ICMPv6EchoRequest: %s", e)
class Scanner(object):
@ -103,41 +155,62 @@ class Scanner(object):
Scan for replies of hosts, maintain the up-to-date database
"""
def __init__(self, interfaces=None, args=None, outdir=None):
def __init__(self, interfaces, autoconfigure=False, outdir=None,
name_mapper=None):
self.interfaces = interfaces
self.autoconfigure = autoconfigure
self.name_mapper = name_mapper
self.config_delay = datetime.timedelta(seconds=3600)
if outdir:
self.outdir = outdir
else:
self.outdir = os.path.join(os.environ['HOME'], '.cdist', 'scan')
os.makedirs(self.outdir, exist_ok=True)
self.running_configs = {}
def handle_pkg(self, pkg):
if ICMPv6EchoReply in pkg:
host = pkg['IPv6'].src
log.verbose("Host %s is alive", host)
host = Host(pkg['IPv6'].src, self.outdir, self.name_mapper)
if host.name():
log.verbose("Host %s (%s) is alive", host.name(),
host.address())
else:
log.verbose("Host %s is alive", host.address())
dir = os.path.join(self.outdir, host)
fname = os.path.join(dir, "last_seen")
host.seen()
now = datetime.datetime.now()
# Configure if needed.
if self.autoconfigure and \
host.last_configured(default=datetime.datetime.min) + \
self.config_delay < datetime.datetime.now():
self.config(host)
os.makedirs(dir, exist_ok=True)
def list(self):
hosts = []
for addr in os.listdir(self.outdir):
hosts.append(Host(addr, self.outdir, self.name_mapper))
# FIXME: maybe adjust the format so we can easily parse again
with open(fname, "w") as fd:
fd.write(f"{now}\n")
return hosts
def config(self):
"""
Configure a host
def config(self, host):
if host.name() is None:
log.debug("config - could not resolve name for %s, aborting.",
host.address())
return
- Assume we are only called if necessary
- However we need to ensure to not run in parallel
- Maybe keep dict storing per host processes
- Save the result
- Save the output -> probably aligned to config mode
previous_config_process = self.running_configs.get(host.name())
if previous_config_process is not None and \
previous_config_process.is_alive():
log.debug("config - is already running for %s, aborting.",
host.name())
"""
log.info("config - running against host %s (%s).", host.name(),
host.address())
p = Process(target=host.configure())
p.start()
self.running_configs[host.name()] = p
def start(self):
self.process = Process(target=self.scan)
@ -148,47 +221,9 @@ class Scanner(object):
def scan(self):
log.debug("Scanning - zzzzz")
sniff(iface=self.interfaces,
filter="icmp6",
prn=self.handle_pkg)
if __name__ == '__main__':
t = Trigger(interfaces=["wlan0"])
t.start()
# Scanner can listen on many interfaces at the same time
s = Scanner(interfaces=["wlan0"])
s.scan()
# Join back the trigger processes
t.join()
# Test in my lan shows:
# [18:48] bridge:cdist% ls -1d fe80::*
# fe80::142d:f0a5:725b:1103
# fe80::20d:b9ff:fe49:ac11
# fe80::20d:b9ff:fe4c:547d
# fe80::219:d2ff:feb2:2e12
# fe80::21b:fcff:feee:f446
# fe80::21b:fcff:feee:f45c
# fe80::21b:fcff:feee:f4b1
# fe80::21b:fcff:feee:f4ba
# fe80::21b:fcff:feee:f4bc
# fe80::21b:fcff:feee:f4c1
# fe80::21d:72ff:fe86:46b
# fe80::42b0:34ff:fe6f:f6f0
# fe80::42b0:34ff:fe6f:f863
# fe80::42b0:34ff:fe6f:f9b2
# fe80::4a5d:60ff:fea1:e55f
# fe80::77a3:5e3f:82cc:f2e5
# fe80::9e93:4eff:fe6c:c1f4
# fe80::ba69:f4ff:fec5:6041
# fe80::ba69:f4ff:fec5:8db7
# fe80::bad8:12ff:fe65:313d
# fe80::bad8:12ff:fe65:d9b1
# fe80::ce2d:e0ff:fed4:2611
# fe80::ce32:e5ff:fe79:7ea7
# fe80::d66d:6dff:fe33:e00
# fe80::e2ff:f7ff:fe00:20e6
# fe80::f29f:c2ff:fe7c:275e
try:
sniff(iface=self.interfaces,
filter="icmp6",
prn=self.handle_pkg)
except Exception as e:
log.error("Could not start listener: %s", e)

82
docs/src/cdist-scan.rst Normal file
View file

@ -0,0 +1,82 @@
Scan
=====
Description
-----------
Runs cdist as a daemon that discover/watch on hosts and reconfigure them
periodically. It is especially useful in netboot-based environment where hosts
boot unconfigured, and to ensure your infrastructure stays in sync with your
configuration.
This feature is still consider to be in **beta** stage, and only operate on
IPv6 (including link-local).
Usage (Examples)
----------------
Discover hosts on local network and configure those whose name is resolved by
the name mapper script.
.. code-block:: sh
$ cdist scan --beta --interface eth0 \
--mode scan --name-mapper path/to/script \
--mode trigger --mode config
List known hosts and exit.
.. code-block:: sh
$ cdist scan --beta --list --name-mapper path/to/script
Please refer to `cdist(1)` for a detailed list of parameters.
Modes
-----
The scanner has 3 modes that can be independently toggled. If the `--mode`
parameter is not specified, only `tigger` and `scan` are enabled (= hosts are
not configured).
trigger
Send ICMPv6 requests to specific hosts or broadcast over IPv6 link-local to
trigger detection by the `scan` module.
scan
Watch for incoming ICMPv6 replies and optionally configure detected hosts.
config
Enable configuration of hosts detected by `scan`.
Name Mapper Script
------------------
The name mapper script takes an IPv6 address as first argument and writes the
resolved name to stdout - if any. The script must be executable.
Simplest script:
.. code-block:: sh
#!/bin/sh
case "$1" in
"fe80::20d:b9ff:fe57:3524")
printf "my-host-01"
;;
"fe80::7603:bdff:fe05:89bb")
printf "my-host-02"
;;
esac
Resolving name from `PTR` DNS record:
.. code-block:: sh
#!/bin/sh
for cmd in dig sed; do
if ! command -v $cmd > /dev/null; then
exit 1
fi
done
dig +short -x "$1" | sed -e 's/.$//'

1
docs/src/index.rst
View file

@ -34,6 +34,7 @@ It natively supports IPv6 since the first release.
cdist-parallelization
cdist-inventory
cdist-preos
cdist-scan
cdist-integration
cdist-reference
cdist-best-practice

28
docs/src/man1/cdist.rst
View file

@ -88,6 +88,9 @@ SYNOPSIS
cdist info [-h] [-a] [-c CONF_DIR] [-e] [-F] [-f] [-g CONFIG_FILE] [-t]
[pattern]
cdist scan -I INTERFACE [--m MODE] [--name-mapper PATH_TO_SCRIPT] [--list]
[-d CONFIG_DELAY] [-t TRIGGER_DELAY]
DESCRIPTION
-----------
@ -641,6 +644,31 @@ Display information for cdist (global explorers, types).
**-t, --types**
Display info for types.
SCAN
----
Runs cdist as a daemon that discover/watch on hosts and reconfigure them
periodically.
**-I INTERFACE, --interfaces INTERFACE**
Interface to listen on. Can be specified multiple times.
**-m MODE, --mode MODE**
Scanner components to enable. Can be specified multiple time to enable more
than one component. Supported modes are: scan, trigger and config. Defaults
to tiggger and scan.
**--name-mapper PATH_TO_SCRIPT**
Path to script used to resolve a remote host name from an IPv6 address.
**--list**
List known hosts and exit.
**-d CONFIG_DELAY, --config-delay CONFIG_DELAY**
How long (seconds) to wait before reconfiguring after last try (config mode only).
**-t TRIGGER_DELAY, --tigger-delay TRIGGER_DELAY**
How long (seconds) to wait between ICMPv6 echo requests (trigger mode only).
CONFIGURATION
-------------