1 files changed, 146 insertions, 0 deletions
diff --git a/src/conf_mode/service_mdns_repeater.py b/src/conf_mode/service_mdns_repeater.py
new file mode 100755
index 000000000..6526c23d1
--- /dev/null
+++ b/src/conf_mode/service_mdns_repeater.py
@@ -0,0 +1,146 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2017-2022 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
+
+from json import loads
+from sys import exit
+from netifaces import ifaddresses, interfaces, AF_INET, AF_INET6
+
+from vyos.config import Config
+from vyos.ifconfig.vrrp import VRRP
+from vyos.template import render
+from vyos.utils.process import call
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+config_file = '/run/avahi-daemon/avahi-daemon.conf'
+systemd_override = r'/run/systemd/system/avahi-daemon.service.d/override.conf'
+vrrp_running_file = '/run/mdns_vrrp_active'
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+
+    base = ['service', 'mdns', 'repeater']
+    if not conf.exists(base):
+        return None
+
+    mdns = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                no_tag_node_value_mangle=True,
+                                get_first_key=True,
+                                with_recursive_defaults=True)
+
+    if mdns:
+        mdns['vrrp_exists'] = conf.exists('high-availability vrrp')
+        mdns['config_file'] = config_file
+
+    return mdns
+
+def verify(mdns):
+    if not mdns or 'disable' in mdns:
+        return None
+
+    # We need at least two interfaces to repeat mDNS advertisments
+    if 'interface' not in mdns or len(mdns['interface']) < 2:
+        raise ConfigError('mDNS repeater requires at least 2 configured interfaces!')
+
+    # For mdns-repeater to work it is essential that the interfaces has
+    # an IPv4 address assigned
+    for interface in mdns['interface']:
+        if interface not in interfaces():
+            raise ConfigError(f'Interface "{interface}" does not exist!')
+
+        if mdns['ip_version'] in ['ipv4', 'both'] and AF_INET not in ifaddresses(interface):
+            raise ConfigError('mDNS repeater requires an IPv4 address to be '
+                                  f'configured on interface "{interface}"')
+
+        if mdns['ip_version'] in ['ipv6', 'both'] and AF_INET6 not in ifaddresses(interface):
+            raise ConfigError('mDNS repeater requires an IPv6 address to be '
+                                  f'configured on interface "{interface}"')
+
+    return None
+
+# Get VRRP states from interfaces, returns only interfaces where state is MASTER
+def get_vrrp_master(interfaces):
+    json_data = loads(VRRP.collect('json'))
+    for group in json_data:
+        if 'data' in group:
+            if 'ifp_ifname' in group['data']:
+                iface = group['data']['ifp_ifname']
+                state = group['data']['state'] # 2 = Master
+                if iface in interfaces and state != 2:
+                    interfaces.remove(iface)
+    return interfaces
+
+def generate(mdns):
+    if not mdns:
+        return None
+
+    if 'disable' in mdns:
+        print('Warning: mDNS repeater will be deactivated because it is disabled')
+        return None
+
+    if mdns['vrrp_exists'] and 'vrrp_disable' in mdns:
+        mdns['interface'] = get_vrrp_master(mdns['interface'])
+
+        if len(mdns['interface']) < 2:
+            return None
+
+    render(config_file, 'mdns-repeater/avahi-daemon.conf.j2', mdns)
+    render(systemd_override, 'mdns-repeater/override.conf.j2', mdns)
+    return None
+
+def apply(mdns):
+    systemd_service = 'avahi-daemon.service'
+    # Reload systemd manager configuration
+    call('systemctl daemon-reload')
+
+    if not mdns or 'disable' in mdns:
+        call(f'systemctl stop {systemd_service}')
+        if os.path.exists(config_file):
+            os.unlink(config_file)
+
+        if os.path.exists(vrrp_running_file):
+            os.unlink(vrrp_running_file)
+    else:
+        if 'vrrp_disable' not in mdns and os.path.exists(vrrp_running_file):
+            os.unlink(vrrp_running_file)
+
+        if mdns['vrrp_exists'] and 'vrrp_disable' in mdns:
+            if not os.path.exists(vrrp_running_file):
+                os.mknod(vrrp_running_file) # vrrp script looks for this file to update mdns repeater
+
+            if len(mdns['interface']) < 2:
+                call(f'systemctl stop {systemd_service}')
+                return None
+
+        call(f'systemctl restart {systemd_service}')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)