mirror of
https://github.com/vincentmli/bpfire.git
synced 2026-04-28 11:43:25 +02:00
b8dd42b9a6
This allows us to restart unbound and all DHCP leases will be re-imported even if the unbound-dhcp-leases-bridge is not restarted. Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
387 lines
9.6 KiB
Python
387 lines
9.6 KiB
Python
#!/usr/bin/python
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###############################################################################
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# #
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# IPFire.org - A linux based firewall #
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# Copyright (C) 2016 Michael Tremer #
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# #
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# This program is free software: you can redistribute it and/or modify #
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# it under the terms of the GNU General Public License as published by #
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# the Free Software Foundation, either version 3 of the License, or #
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# (at your option) any later version. #
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# #
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# This program is distributed in the hope that it will be useful, #
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# but WITHOUT ANY WARRANTY; without even the implied warranty of #
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
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# GNU General Public License for more details. #
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# #
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# You should have received a copy of the GNU General Public License #
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# along with this program. If not, see <http://www.gnu.org/licenses/>. #
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# #
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###############################################################################
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import argparse
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import datetime
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import daemon
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import logging
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import logging.handlers
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import re
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import signal
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import subprocess
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import inotify.adapters
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LOCAL_TTL = 60
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def setup_logging(loglevel=logging.INFO):
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log = logging.getLogger("dhcp")
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log.setLevel(loglevel)
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handler = logging.handlers.SysLogHandler(address="/dev/log", facility="daemon")
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handler.setLevel(loglevel)
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formatter = logging.Formatter("%(name)s[%(process)d]: %(message)s")
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handler.setFormatter(formatter)
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log.addHandler(handler)
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return log
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log = logging.getLogger("dhcp")
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class UnboundDHCPLeasesBridge(object):
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def __init__(self, dhcp_leases_file, unbound_leases_file):
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self.leases_file = dhcp_leases_file
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self.unbound = UnboundConfigWriter(unbound_leases_file)
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self.running = False
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def run(self):
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log.info("Unbound DHCP Leases Bridge started on %s" % self.leases_file)
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self.running = True
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# Initially read leases file
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self.update_dhcp_leases()
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i = inotify.adapters.Inotify([self.leases_file])
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for event in i.event_gen():
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# End if we are requested to terminate
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if not self.running:
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break
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if event is None:
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continue
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header, type_names, watch_path, filename = event
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# Update leases after leases file has been modified
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if "IN_MODIFY" in type_names:
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self.update_dhcp_leases()
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log.info("Unbound DHCP Leases Bridge terminated")
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def update_dhcp_leases(self):
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log.info("Reading DHCP leases from %s" % self.leases_file)
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leases = DHCPLeases(self.leases_file)
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self.unbound.update_dhcp_leases(leases)
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def terminate(self):
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self.running = False
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class DHCPLeases(object):
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regex_leaseblock = re.compile(r"lease (?P<ipaddr>\d+\.\d+\.\d+\.\d+) {(?P<config>[\s\S]+?)\n}")
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def __init__(self, path):
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self.path = path
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self._leases = self._parse()
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def __iter__(self):
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return iter(self._leases)
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def _parse(self):
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leases = []
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with open(self.path) as f:
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# Read entire leases file
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data = f.read()
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for match in self.regex_leaseblock.finditer(data):
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block = match.groupdict()
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ipaddr = block.get("ipaddr")
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config = block.get("config")
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properties = self._parse_block(config)
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# Skip any abandoned leases
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if not "hardware" in properties:
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continue
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lease = Lease(ipaddr, properties)
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# Check if a lease for this Ethernet address already
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# exists in the list of known leases. If so replace
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# if with the most recent lease
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for i, l in enumerate(leases):
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if l.hwaddr == lease.hwaddr:
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leases[i] = max(lease, l)
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break
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else:
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leases.append(lease)
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return leases
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def _parse_block(self, block):
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properties = {}
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for line in block.splitlines():
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if not line:
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continue
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# Remove trailing ; from line
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if line.endswith(";"):
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line = line[:-1]
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# Invalid line if it doesn't end with ;
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else:
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continue
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# Remove any leading whitespace
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line = line.lstrip()
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# We skip all options and sets
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if line.startswith("option") or line.startswith("set"):
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continue
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# Split by first space
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key, val = line.split(" ", 1)
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properties[key] = val
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return properties
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class Lease(object):
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def __init__(self, ipaddr, properties):
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self.ipaddr = ipaddr
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self._properties = properties
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def __repr__(self):
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return "<%s %s for %s (%s)>" % (self.__class__.__name__,
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self.ipaddr, self.hwaddr, self.hostname)
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def __eq__(self, other):
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return self.ipaddr == other.ipaddr and self.hwaddr == other.hwaddr
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def __gt__(self, other):
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if not self.ipaddr == other.ipaddr:
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return
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if not self.hwaddr == other.hwaddr:
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return
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return self.time_starts > other.time_starts
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@property
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def binding_state(self):
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state = self._properties.get("binding")
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if state:
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state = state.split(" ", 1)
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return state[1]
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@property
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def active(self):
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return self.binding_state == "active"
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@property
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def hwaddr(self):
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hardware = self._properties.get("hardware")
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if not hardware:
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return
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ethernet, address = hardware.split(" ", 1)
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return address
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@property
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def hostname(self):
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hostname = self._properties.get("client-hostname")
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# Remove any ""
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if hostname:
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hostname = hostname.replace("\"", "")
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return hostname
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@property
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def domain(self):
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return "local" # XXX
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@property
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def fqdn(self):
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return "%s.%s" % (self.hostname, self.domain)
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@staticmethod
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def _parse_time(s):
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return datetime.datetime.strptime(s, "%w %Y/%m/%d %H:%M:%S")
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@property
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def time_starts(self):
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starts = self._properties.get("starts")
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if starts:
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return self._parse_time(starts)
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@property
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def time_ends(self):
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ends = self._properties.get("ends")
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if not ends or ends == "never":
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return
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return self._parse_time(ends)
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@property
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def expired(self):
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if not self.time_ends:
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return self.time_starts > datetime.datetime.utcnow()
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return self.time_starts > datetime.datetime.utcnow() > self.time_ends
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@property
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def rrset(self):
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return [
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# Forward record
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(self.fqdn, "%s" % LOCAL_TTL, "IN A", self.ipaddr),
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# Reverse record
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(self.ipaddr, "%s" % LOCAL_TTL, "IN PTR", self.fqdn),
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]
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class UnboundConfigWriter(object):
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def __init__(self, path):
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self.path = path
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@property
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def existing_leases(self):
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local_data = self._control("list_local_data")
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ret = {}
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for line in local_data.splitlines():
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try:
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hostname, ttl, x, record_type, content = line.split("\t")
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except ValueError:
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continue
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# Ignore everything that is not A or PTR
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if not record_type in ("A", "PTR"):
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continue
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if hostname.endswith("."):
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hostname = hostname[:-1]
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if content.endswith("."):
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content = content[:-1]
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if record_type == "A":
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ret[hostname] = content
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elif record_type == "PTR":
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ret[content] = hostname
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return ret
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def update_dhcp_leases(self, leases):
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# Strip all non-active or expired leases
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leases = [l for l in leases if l.active and not l.expired]
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# Find any leases that have expired or do not exist any more
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removed_leases = []
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for fqdn, address in self.existing_leases.items():
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if not fqdn in (l.fqdn for l in leases):
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removed_leases += [fqdn, address]
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# Find any leases that have been added
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new_leases = [l for l in leases
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if l.fqdn not in self.existing_leases]
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# End here if nothing has changed
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if not new_leases and not removed_leases:
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return
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# Write out all leases
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self.write_dhcp_leases(leases)
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# Update unbound about changes
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for hostname in removed_leases:
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log.debug("Removing all records for %s" % hostname)
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self._control("local_data_remove", hostname)
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for l in new_leases:
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for rr in l.rrset:
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log.debug("Adding new record %s" % " ".join(rr))
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self._control("local_data", *rr)
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def write_dhcp_leases(self, leases):
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with open(self.path, "w") as f:
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for l in leases:
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for rr in l.rrset:
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f.write("local-data: \"%s\"\n" % " ".join(rr))
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def _control(self, *args):
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command = ["unbound-control"]
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command.extend(args)
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try:
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return subprocess.check_output(command)
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# Log any errors
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except subprocess.CalledProcessError as e:
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log.critical("Could not run %s, error code: %s: %s" % (
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" ".join(command), e.returncode, e.output))
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if __name__ == "__main__":
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parser = argparse.ArgumentParser(description="Bridge for DHCP Leases and Unbound DNS")
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# Daemon Stuff
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parser.add_argument("--daemon", "-d", action="store_true",
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help="Launch as daemon in background")
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parser.add_argument("--verbose", "-v", action="count", help="Be more verbose")
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# Paths
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parser.add_argument("--dhcp-leases", default="/var/state/dhcp/dhcpd.leases",
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metavar="PATH", help="Path to the DHCPd leases file")
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parser.add_argument("--unbound-leases", default="/etc/unbound/dhcp-leases.conf",
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metavar="PATH", help="Path to the unbound configuration file")
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# Parse command line arguments
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args = parser.parse_args()
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# Setup logging
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if args.verbose == 1:
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loglevel = logging.INFO
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elif args.verbose >= 2:
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loglevel = logging.DEBUG
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else:
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loglevel = logging.WARN
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setup_logging(loglevel)
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bridge = UnboundDHCPLeasesBridge(args.dhcp_leases, args.unbound_leases)
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ctx = daemon.DaemonContext(detach_process=args.daemon)
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ctx.signal_map = {
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signal.SIGHUP : bridge.update_dhcp_leases,
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signal.SIGTERM : bridge.terminate,
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}
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with ctx:
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bridge.run()
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