Icinga/Nagios check for XMPP
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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Nagios compatible check for XMPP servers.
# Copyright (C) 2015-2021 Jan Dittberner
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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/>.
#
from __future__ import absolute_import
from datetime import datetime
from select import select
from xml.sax.handler import ContentHandler, feature_namespaces
import logging
import os.path
import socket
import ssl
from defusedxml.sax import make_parser
import nagiosplugin
__author__ = "Jan Dittberner"
__version__ = "0.3.2"
NS_IETF_XMPP_SASL = 'urn:ietf:params:xml:ns:xmpp-sasl'
NS_IETF_XMPP_TLS = 'urn:ietf:params:xml:ns:xmpp-tls'
NS_IETF_XMPP_STREAMS = 'urn:ietf:params:xml:ns:xmpp-streams'
NS_JABBER_CAPS = 'http://jabber.org/protocol/caps'
NS_ETHERX_STREAMS = 'http://etherx.jabber.org/streams'
XMPP_STATE_NEW = 'new'
XMPP_STATE_STREAM_START = 'started'
XMPP_STATE_RECEIVED_FEATURES = 'received features'
XMPP_STATE_FINISHED = 'finished'
XMPP_STATE_ERROR = 'error'
XMPP_STATE_PROCEED_STARTTLS = 'proceed with starttls'
_LOG = logging.getLogger('nagiosplugin')
class XmppException(Exception):
"""
Custom exception class.
"""
def __init__(self, message):
self.message = message
super(XmppException, self).__init__()
class XmppStreamError(object):
"""
XMPP stream error class.
"""
condition = None
text = None
other_elements = {}
def str(self):
if self.text:
return "{condition}: {text}".format(
condition=self.condition, text=self.text)
return self.condition
class XmppResponseHandler(ContentHandler):
"""
SAX content handler for XMPP stream content.
"""
seen_elements = set()
mechanisms = []
starttls = False
tlsrequired = False
capabilities = {}
state = XMPP_STATE_NEW
streaminfo = None
inelem = []
level = 0
def __init__(self, expect_starttls):
self.expect_starttls = expect_starttls
super(XmppResponseHandler, self).__init__()
def startElementNS(self, name, qname, attrs):
self.inelem.append(name)
self.seen_elements.add(name)
if name == (NS_ETHERX_STREAMS, 'stream'):
self.state = XMPP_STATE_STREAM_START
self.streaminfo = dict([
(qname, attrs.getValueByQName(qname)) for
qname in attrs.getQNames()])
elif name == (NS_IETF_XMPP_TLS, 'starttls'):
self.starttls = True
elif (
self.inelem[-2] == (NS_IETF_XMPP_TLS, 'starttls') and
name == (NS_IETF_XMPP_TLS, 'required')
):
self.tlsrequired = True
_LOG.info("info other side requires TLS")
elif name == (NS_JABBER_CAPS, 'c'):
for qname in attrs.getQNames():
self.capabilities[qname] = attrs.getValueByQName(qname)
elif name == (NS_ETHERX_STREAMS, 'error'):
self.state = XMPP_STATE_ERROR
self.errorinstance = XmppStreamError()
elif (
self.state == XMPP_STATE_ERROR and
name != (NS_IETF_XMPP_STREAMS, 'text')
):
if name[0] == NS_IETF_XMPP_STREAMS:
self.errorinstance.condition = name[1]
else:
self.errorinstance.other_elements[name] = {'attrs': dict([
(qname, attrs.getValueByQName(qname)) for
qname in attrs.getQNames()
])}
_LOG.debug('start %s (%s)', name, attrs.getQNames())
def endElementNS(self, name, qname):
if name == (NS_ETHERX_STREAMS, 'features'):
self.state = XMPP_STATE_RECEIVED_FEATURES
elif name == (NS_ETHERX_STREAMS, 'stream'):
self.state = XMPP_STATE_FINISHED
elif name == (NS_ETHERX_STREAMS, 'error'):
raise XmppException("XMPP stream error: {error}".format(
error=self.errorinstance))
elif name == (NS_IETF_XMPP_TLS, 'proceed'):
self.state = XMPP_STATE_PROCEED_STARTTLS
elif name == (NS_IETF_XMPP_TLS, 'failure'):
raise XmppException("starttls initiation failed")
_LOG.debug('end %s', name)
del self.inelem[-1]
def characters(self, content):
elem = self.inelem[-1]
if elem == (NS_IETF_XMPP_SASL, 'mechanism'):
self.mechanisms.append(content)
elif self.state == XMPP_STATE_ERROR:
if elem == (NS_IETF_XMPP_STREAMS, 'text'):
self.errorinstance.text = content
else:
self.errorinstance.other_elements[elem]['text'] = content
else:
_LOG.warning('ignored content in %s: %s', self.inelem, content)
def is_valid_start(self):
if not self.state == XMPP_STATE_RECEIVED_FEATURES:
raise XmppException('XMPP feature list is not finished')
if self.expect_starttls is True and self.starttls is False:
raise XmppException('expected STARTTLS capable service')
if (
'version' not in self.streaminfo or
self.streaminfo['version'] != '1.0'
):
_LOG.warning(
'unknown stream version %s', self.streaminfo['version'])
return True
class Xmpp(nagiosplugin.Resource):
"""
Xmpp resource.
"""
state = nagiosplugin.Unknown
cause = None
socket = None
daysleft = None
def __init__(
self, host_address, port, ipv6, is_server, starttls,
servername, checkcerts, caroots
):
self.address = host_address
self.port = port
self.ipv6 = ipv6
self.is_server = is_server
self.starttls = starttls
self.servername = servername
self.checkcerts = checkcerts
self.caroots = caroots
self.make_parser()
self.set_content_handler()
def make_parser(self):
"""
Create and configure a SAX parser instance.
"""
self.parser = make_parser()
self.parser.setFeature(feature_namespaces, True)
def set_content_handler(self):
"""
Set the XMPP SAX content handler.
"""
self.contenthandler = XmppResponseHandler(
expect_starttls=self.starttls)
self.parser.setContentHandler(self.contenthandler)
def get_addrinfo(self):
"""
Perform the DNS lookup and return a list of potential socket address
tuples as returned by :py:method:`socket.getaddrinfo`.
"""
if self.ipv6 is None:
addrfamily = 0
elif self.ipv6 is True:
addrfamily = socket.AF_INET6
else:
addrfamily = socket.AF_INET
return socket.getaddrinfo(
self.address, self.port, addrfamily, socket.SOCK_STREAM,
socket.IPPROTO_TCP)
self.result = nagiosplugin.Critical
def open_socket(self, addrinfo):
"""
Open a client socket based on information in the addrinfo list of
tuples.
"""
for res in addrinfo:
af, socktype, proto, canonname, sa = res
try:
s = socket.socket(af, socktype, proto)
except socket.error:
s = None
continue
try:
s.connect(sa)
except socket.error:
s.close()
s = None
continue
break
if s is None:
raise XmppException("could not open socket")
return s
def handle_xmpp_stanza(
self, message_str, timeout=0.1, expected_state=None
):
"""
Handle a single XMPP message.
This method sends the message specified as ``message_str`` and receives
input from the remote XMPP server. The response message is passed to
the SAX parser.
The method can optionally check for a specific state of the SAX content
handler that can be specified as ``expected_state`` which needs to be
one of the ``XMPP_STATE_*`` constants specified in the head of this
file.
"""
self.socket.sendall(message_str.encode('utf-8'))
_LOG.debug("wrote %s", message_str)
chunks = []
while True:
rready, wready, xready = select([self.socket], [], [], timeout)
if self.socket in rready:
data = self.socket.recv(4096)
if not data:
break
chunks.append(data)
else:
break
xmltext = b''.join(chunks).decode('utf-8')
_LOG.debug("read %s", xmltext)
self.parser.feed(xmltext)
if (
expected_state is not None and
self.contenthandler.state != expected_state
):
raise XmppException(
"unexpected state %s" % self.contenthandler.state)
def start_stream(self):
"""
Start a XMPP conversation with the server.
"""
if self.is_server:
self.handle_xmpp_stanza((
"<?xml version='1.0' ?><stream:stream to='{servername}' "
"xmlns='jabber:server' "
"xmlns:stream='http://etherx.jabber.org/streams' "
"version='1.0'>"
).format(servername=self.servername),
expected_state=XMPP_STATE_RECEIVED_FEATURES)
else:
self.handle_xmpp_stanza((
"<?xml version='1.0' ?><stream:stream to='{servername}' "
"xmlns='jabber:client' "
"xmlns:stream='http://etherx.jabber.org/streams' "
"version='1.0'>"
).format(servername=self.servername),
expected_state=XMPP_STATE_RECEIVED_FEATURES)
def setup_ssl_context(self):
"""
Setup the SSL/TLS context.
"""
context = ssl.create_default_context()
context.options = ssl.OP_NO_SSLv2 | ssl.OP_NO_SSLv3
if not self.checkcerts:
context.check_hostname = False
context.verify_mode = ssl.CERT_NONE
else:
context.verify_mode = ssl.CERT_REQUIRED
if self.caroots:
if os.path.isfile(self.caroots):
kwargs = {'cafile': self.caroots}
else:
kwargs = {'capath': self.caroots}
context.load_verify_locations(**kwargs)
else:
context.load_default_certs()
return context
def initiate_tls(self):
"""
Switch the client socket to TLS by performing a TLS handshake. If
certificate checks are requested the method checks the certificate
validity.
"""
_LOG.debug("start initiate_tls()")
self.handle_xmpp_stanza(
"<starttls xmlns='{xmlns}'/>".format(xmlns=NS_IETF_XMPP_TLS),
expected_state=XMPP_STATE_PROCEED_STARTTLS)
sslcontext = self.setup_ssl_context()
try:
self.socket = sslcontext.wrap_socket(
self.socket, server_hostname=self.servername)
_LOG.info("TLS socket setup successful")
except ssl.SSLError as ssle:
raise XmppException("SSL error %s" % ssle.strerror)
except ssl.CertificateError as certerr:
raise XmppException("Certificate error %s" % certerr)
self.starttls = False
# reset infos retrieved previously as written in RFC 3920 sec. 5.
self.parser.reset()
if self.checkcerts:
certinfo = self.socket.getpeercert()
_LOG.debug("got the following certificate info: %s", certinfo)
_LOG.info(
"certificate is valid from %s until %s",
certinfo['notBefore'], certinfo['notAfter'])
enddate = ssl.cert_time_to_seconds(certinfo['notAfter'])
remaining = datetime.fromtimestamp(enddate) - datetime.now()
self.daysleft = remaining.days
# start new parsing
self.make_parser()
self.set_content_handler()
self.start_stream()
if not self.contenthandler.is_valid_start():
raise XmppException("no valid response to XMPP client request")
_LOG.debug("end initiate_tls()")
def handle_xmpp(self):
"""
Perform the XMPP conversation.
"""
_LOG.debug("start handle_xmpp()")
self.start_stream()
if not self.contenthandler.is_valid_start():
raise XmppException("no valid response to XMPP client request")
if self.starttls is True or self.contenthandler.tlsrequired:
self.initiate_tls()
self.handle_xmpp_stanza("</stream:stream>")
_LOG.debug("end handle_xmpp()")
def probe(self):
"""
Entry point for the nagiosplugin.Resource APIs. Wraps the call to
:py:method:`Xmpp.handle_xmpp` and handles errors appropriately.
"""
start = datetime.now()
_LOG.debug("start probe() at %s", start)
try:
addrinfo = self.get_addrinfo()
self.socket = self.open_socket(addrinfo)
try:
self.handle_xmpp()
finally:
self.socket.close()
self.parser.close()
except socket.gaierror as e:
self.state = nagiosplugin.Critical
self.cause = str(e)
_LOG.debug("got an gaierror %s", e)
return nagiosplugin.Metric("time", "unknown")
except XmppException as e:
self.state = nagiosplugin.Critical
self.cause = e.message
_LOG.debug("got an XmppException %s", e)
yield nagiosplugin.Metric('time', 'unknown')
return nagiosplugin.Metric('daysleft', 'unknown')
end = datetime.now()
_LOG.debug("end probe() at %s", end)
yield nagiosplugin.Metric(
'time', (end - start).total_seconds(), 's', min=0)
yield nagiosplugin.Metric('daysleft', self.daysleft, 'd')
class XmppContext(nagiosplugin.ScalarContext):
"""
Context for checking the connection time and potential errors that occurred
during the XMPP check.
"""
def evaluate(self, metric, resource):
"""
Evaluate the time contained in the ``metric`` or the resource state in
case of an exception that has been handled during the check.
"""
if resource.cause:
return nagiosplugin.Result(resource.state, resource.cause, metric)
return super(XmppContext, self).evaluate(metric, resource)
class DaysValidContext(nagiosplugin.Context):
"""
Context for checking the certificate expiry date.
"""
fmt_hint = "less than {value} days"
def __init__(
self, name, warndays=0, critdays=0,
fmt_metric='certificate valid for {value} days'
):
super(DaysValidContext, self).__init__(name, fmt_metric=fmt_metric)
self.warning = nagiosplugin.Range('@%d:' % warndays)
self.critical = nagiosplugin.Range('@%d:' % critdays)
self.warndays = warndays
self.critdays = critdays
def evaluate(self, metric, resource):
if resource.checkcerts and metric.value is not None:
if self.critical.match(metric.value):
return nagiosplugin.Result(
nagiosplugin.Critical,
hint=self.fmt_hint.format(value=self.critdays),
metric=metric)
if self.warning.match(metric.value):
return nagiosplugin.Result(
nagiosplugin.Warn,
hint=self.fmt_hint.format(value=self.warndays),
metric=metric)
return nagiosplugin.Result(
nagiosplugin.Ok, "", metric)
return nagiosplugin.Result(nagiosplugin.Ok)
def performance(self, metric, resource):
if resource.checkcerts and metric.value is not None:
return nagiosplugin.Performance('daysvalid', metric.value, '')
return None
class XmppSummary(nagiosplugin.Summary):
"""
Summary instance that outputs all metrics if the check results are ok.
"""
def ok(self, results):
return ", ".join([str(res) for res in results])
@nagiosplugin.guarded
def main():
"""
Handle command line parameters and initiate the check.
"""
import argparse
parser = argparse.ArgumentParser(description="Check XMPP services")
host_address = parser.add_mutually_exclusive_group(required=True)
host_address.add_argument("-H", "--host-address", help="host address")
host_address.add_argument(
"--hostname", help="host name, alternative for host-address",
dest="host_address")
parser.add_argument(
"-p", "--port", help="port", type=int)
is_server = parser.add_mutually_exclusive_group()
is_server.add_argument(
"--s2s", dest="is_server", action='store_true',
help="server to server (s2s)")
is_server.add_argument(
"--c2s", dest="is_server", action='store_false',
help="client to server (c2s)")
ipv6 = parser.add_mutually_exclusive_group()
ipv6.add_argument(
"-4", "--ipv4", dest="ipv6", action='store_false',
help="enforce IPv4")
ipv6.add_argument(
"-6", "--ipv6", dest="ipv6", action='store_true',
help="enforce IPv6")
parser.add_argument(
"--servername", help="server name to be used")
parser.add_argument(
"--starttls",
action='store_true', help="check whether the service allows starttls")
parser.add_argument(
"-w", "--warning", metavar="SECONDS", default='',
help="return warning if connection setup takes longer than SECONDS")
parser.add_argument(
"-c", "--critical", metavar="SECONDS", default='',
help="return critical if connection setup takes longer than SECONDS")
parser.add_argument(
"--no-check-certificates", dest='checkcerts', action='store_false',
help="do not check whether the XMPP server's certificate is valid")
parser.add_argument(
"-r", "--ca-roots", dest="caroots",
help="path to a file or directory where CA certifcates can be found")
parser.add_argument(
"--warn-days", dest="warndays", type=int, default=0,
help=(
"set state to WARN if the certificate is valid for not more than "
"the given number of days"))
parser.add_argument(
"--crit-days", dest="critdays", type=int, default=0,
help=(
"set state to CRITICAL if the certificate is valid for not more "
"than the given number of days"))
parser.add_argument(
'-v', '--verbose', action='count', default=0)
parser.set_defaults(is_server=False, ipv6=None, checkcerts=True)
args = parser.parse_args()
if args.port is None:
if args.is_server:
args.port = 5269
else:
args.port = 5222
if args.servername is None:
args.servername = args.host_address
kwargs = vars(args)
warning, critical, warndays, critdays, verbose = [
kwargs.pop(arg) for arg in
('warning', 'critical', 'warndays', 'critdays', 'verbose')
]
check = nagiosplugin.Check(
Xmpp(**kwargs),
XmppContext(
'time', warning, critical, fmt_metric="request took {value}{uom}"),
DaysValidContext('daysleft', warndays, critdays),
XmppSummary(),
)
check.main(verbose=verbose, timeout=0)
if __name__ == "__main__":
main()