dnsmasq: add dnsmasq watcher; closes #5119

plist

@@ -738,6 +738,7 @@
 /usr/local/opnsense/scripts/OPNsense/Monit/setup.sh
 /usr/local/opnsense/scripts/auth/add_user.php
 /usr/local/opnsense/scripts/dhcp/cleanup_leases4.php
+/usr/local/opnsense/scripts/dhcp/dnsmasq_watcher.py
 /usr/local/opnsense/scripts/dhcp/get_leases.py
 /usr/local/opnsense/scripts/dhcp/prefixes.php
 /usr/local/opnsense/scripts/dhcp/unbound_watcher.py

src/etc/inc/plugins.inc.d/dnsmasq.inc

@@ -278,24 +278,18 @@ function _dnsmasq_dhcpleases_start()
 {
     global $config;
 
-    /* XXX this code is going away soon enough */
-    $leases = '/var/dhcpd/var/db/dhcpd.leases';
-
-    if (isset($config['dnsmasq']['regdhcp']) && file_exists($leases)) {
+    if (isset($config['dnsmasq']['regdhcp'])) {
         $domain = $config['system']['domain'];
         if (isset($config['dnsmasq']['regdhcpdomain'])) {
             $domain = $config['dnsmasq']['regdhcpdomain'];
         }
-        mwexecf(
-            '/usr/local/sbin/dhcpleases -l %s -d %s -p %s -h %s',
-            [$leases, $domain, '/var/run/dnsmasq.pid', '/var/etc/dnsmasq-leases']
-        );
+        mwexecf('/usr/local/opnsense/scripts/dhcp/dnsmasq_watcher.py --domain %s', $domain);
     }
 }
 
 function _dnsmasq_dhcpleases_stop()
 {
-    killbypid('/var/run/dhcpleases.pid', 'TERM', true);
+    killbypid('/var/run/dnsmasq_dhcpd.pid', 'TERM', true);
 }
 
 function dnsmasq_hosts_generate()

src/opnsense/scripts/dhcp/dnsmasq_watcher.py

@@ -0,0 +1,126 @@
+#!/usr/local/bin/python3
+
+"""
+    Copyright (c) 2016-2020 Ad Schellevis <ad@opnsense.org>
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in the
+     documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+
+    --------------------------------------------------------------------------------------
+    watch dhcp lease file and build include file for dnsmasq
+"""
+import ipaddress
+import os
+import sys
+import time
+import argparse
+import syslog
+import signal
+from configparser import ConfigParser
+sys.path.insert(0, "/usr/local/opnsense/site-python")
+from daemonize import Daemonize
+import watchers.dhcpd
+
+
+def run_watcher(target_filename, default_domain, watch_file, service_pid):
+    # cleanup interval (seconds)
+    cleanup_interval = 60
+
+    # initiate lease watcher and setup cache
+    dhcpdleases = watchers.dhcpd.DHCPDLease(watch_file)
+    cached_leases = dict()
+
+    # start watching dhcp leases
+    last_cleanup = time.time()
+
+    while True:
+        for lease in dhcpdleases.watch():
+            if 'ends' in lease and lease['ends'] > time.time() \
+                    and 'client-hostname' in lease and 'address' in lease and lease['client-hostname']:
+                address = ipaddress.ip_address(lease['address'])
+                lease['domain'] = default_domain
+                cached_leases[lease['address']] = lease
+                dhcpd_changed = True
+
+        if time.time() - last_cleanup > cleanup_interval:
+            # cleanup every x seconds
+            last_cleanup = time.time()
+            addresses = list(cached_leases)
+            for address in addresses:
+                if cached_leases[address]['ends'] < time.time():
+                    syslog.syslog(
+                        syslog.LOG_NOTICE,
+                        "dhcpd expired %s @ %s" % (cached_leases[address]['client-hostname'], address)
+                    )
+                    del cached_leases[address]
+                    dhcpd_changed = True
+
+        if dhcpd_changed:
+            with open(target_filename, 'w') as dnsmasq_conf:
+                dnsmasq_conf.write('# dynamic entries from dhcpd.leases automatically entered\n')
+                for address in cached_leases:
+                    dnsmasq_conf.write('%s %s.%s %s\n' % (
+                        address,
+                        cached_leases[address]['client-hostname'],
+                        cached_leases[address]['domain'],
+                        cached_leases[address]['client-hostname']
+                    ))
+
+            pid = int(open(service_pid).read())
+            os.kill(pid, signal.SIGHUP)
+
+        dhcpd_changed = False
+
+        # wait for next cycle
+        time.sleep(1)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--domain', help='default domain to use', default='local')
+    parser.add_argument('--foreground', help='run in forground', default=False, action='store_true')
+    parser.add_argument('--pid', help='pid file location', default='/var/run/dnsmasq_dhcpd.pid')
+    parser.add_argument('--servicepid', help='dnsmasq pid file location', default='/var/run/dnsmasq.pid')
+    parser.add_argument('--source', help='source leases file', default='/var/dhcpd/var/db/dhcpd.leases')
+    parser.add_argument('--target', help='target config file', default='/var/etc/dnsmasq-leases')
+
+    inputargs = parser.parse_args()
+
+    syslog.openlog('dnsmasq', logoption=syslog.LOG_DAEMON, facility=syslog.LOG_LOCAL4)
+
+    if inputargs.foreground:
+        run_watcher(
+            target_filename=inputargs.target,
+            default_domain=inputargs.domain,
+            watch_file=inputargs.source,
+            service_pid=inputargs.servicepid
+        )
+    else:
+        syslog.syslog(syslog.LOG_NOTICE, 'daemonize dnsmasq dhcpd watcher.')
+        cmd = lambda : run_watcher(
+            target_filename=inputargs.target,
+            default_domain=inputargs.domain,
+            watch_file=inputargs.source,
+            service_pid=inputargs.servicepid
+        )
+        daemon = Daemonize(app="dnsmasq_dhcpd", pid=inputargs.pid, action=cmd)
+        daemon.start()