T5518: Add basic MLD support

Currently VyOS has `protocol igmp` option to enable IGMP querier and reports through FRR's pimd.

I would like to add support for IPv6 as well since FRR's IPv6 multicast functionality has significantly improved.

Enabling both MLD and IGMP on a VyOS router will allow us to turn on multicast snooping on layer-3 switches in dual-stack networks.

Example commands:

```
// Enable on interface eth0
set protocols pimv6 interface eth0

// Explicitly join multicast group ff18::1234 on interface eth1
set protocols pimv6 interface eth1 mld join ff18::1234

// Explicitly join source-specific multicast group ff38::5678 with source address 2001:db8::1 on interface eth1
set protocols pimv6 interface eth1 mld join ff38::5678 source 2001:db8::1
```

data/templates/frr/daemons.frr.tmpl

@@ -6,6 +6,7 @@ ripd=yes
 ripngd=yes
 isisd=yes
 pimd=no
+pim6d=yes
 ldpd=yes
 nhrpd=no
 eigrpd=yes
@@ -38,6 +39,7 @@ isisd_options="  --daemon -A 127.0.0.1
 {%- if snmp is defined and snmp.isisd is defined %} -M snmp{% endif -%}
 "
 pimd_options="  --daemon -A 127.0.0.1"
+pim6d_options=" --daemon -A ::1"
 ldpd_options="  --daemon -A 127.0.0.1
 {%- if snmp is defined and snmp.ldpd is defined %} -M snmp{% endif -%}
 "

data/templates/frr/pim6d.frr.j2

@@ -0,0 +1,32 @@
+!
+{% if interface is vyos_defined %}
+{%     for iface, iface_config in interface.items() %}
+interface {{ iface }}
+{%         if iface_config.mld is vyos_defined and iface_config.mld.disable is not vyos_defined %}
+ ipv6 mld
+{%             if iface_config.mld.version is vyos_defined %}
+ ipv6 mld version {{ iface_config.mld.version }}
+{%             endif %}
+{%             if iface_config.mld.query_interval is vyos_defined %}
+ ipv6 mld query-interval {{ iface_config.mld.query_interval }}
+{%             endif %}
+{%             if iface_config.mld.query_max_resp_time is vyos_defined %}
+ ipv6 mld query-max-response-time {{ iface_config.mld.query_max_resp_time }}
+{%             endif %}
+{%             if iface_config.mld.join is vyos_defined %}
+{%                 for group, group_config in iface_config.mld.join.items() %}
+{%                     if group_config.source is vyos_defined %}
+{%                         for source in group_config.source %}
+ ipv6 mld join {{ group }} {{ source }}
+{%                         endfor %}
+{%                     else %}
+ ipv6 mld join {{ group }}
+{%                     endif %}
+{%                 endfor %}
+{%             endif %}
+{%         endif %}
+exit
+!
+{%     endfor %}
+!
+{% endif %}

interface-definitions/protocols-pimv6.xml.in

@@ -0,0 +1,104 @@
+<?xml version="1.0"?>
+<!-- Protocol Independent Multicast for IPv6 (PIMv6) configuration -->
+<interfaceDefinition>
+  <node name="protocols">
+    <children>
+      <node name="pimv6" owner="${vyos_conf_scripts_dir}/protocols_pimv6.py">
+        <properties>
+          <help>Protocol Independent Multicast for IPv6 (PIMv6)</help>
+        </properties>
+        <children>
+          <tagNode name="interface">
+            <properties>
+              <help>PIMv6 interface</help>
+              <completionHelp>
+                <script>${vyos_completion_dir}/list_interfaces</script>
+              </completionHelp>
+            </properties>
+            <children>
+              <node name="mld">
+                <properties>
+                  <help>Multicast Listener Discovery (MLD)</help>
+                </properties>
+                <children>
+                  #include <include/generic-disable-node.xml.i>
+                  <tagNode name="join">
+                    <properties>
+                      <help>MLD join multicast group</help>
+                      <valueHelp>
+                        <format>ipv6</format>
+                        <description>Multicast group address</description>
+                      </valueHelp>
+                      <constraint>
+                        <validator name="ipv6-address"/>
+                      </constraint>
+                    </properties>
+                    <children>
+                      <leafNode name="source">
+                        <properties>
+                          <help>Source address</help>
+                          <valueHelp>
+                            <format>ipv6</format>
+                            <description>Source address</description>
+                          </valueHelp>
+                          <constraint>
+                            <validator name="ipv6-address"/>
+                          </constraint>
+                          <multi/>
+                        </properties>
+                      </leafNode>
+                    </children>
+                  </tagNode>
+                  <leafNode name="version">
+                    <properties>
+                      <help>MLD version</help>
+                      <completionHelp>
+                        <list>1 2</list>
+                      </completionHelp>
+                      <valueHelp>
+                        <format>1</format>
+                        <description>MLD version 1</description>
+                      </valueHelp>
+                     <valueHelp>
+                        <format>2</format>
+                        <description>MLD version 2</description>
+                      </valueHelp>
+                      <constraint>
+                        <validator name="numeric" argument="--range 1-2"/>
+                      </constraint>
+                    </properties>
+                    <defaultValue>2</defaultValue>
+                  </leafNode>
+                  <leafNode name="query-interval">
+                    <properties>
+                      <help>MLD query interval</help>
+                      <valueHelp>
+                        <format>u32:1-65535</format>
+                        <description>Query interval in seconds</description>
+                      </valueHelp>
+                      <constraint>
+                        <validator name="numeric" argument="--range 1-65535"/>
+                      </constraint>
+                    </properties>
+                  </leafNode>
+                  <leafNode name="query-max-response-time">
+                    <properties>
+                      <help>MLD max query response time</help>
+                      <valueHelp>
+                        <format>u32:1-65535</format>
+                        <description>Query response value in deci-seconds</description>
+                      </valueHelp>
+                      <constraint>
+                        <validator name="numeric" argument="--range 1-65535"/>
+                      </constraint>
+                    </properties>
+                  </leafNode>
+                </children>
+              </node>
+            </children>
+          </tagNode>
+        </children>
+      </node>
+    </children>
+  </node>
+</interfaceDefinition>

python/vyos/frr.py

@@ -88,7 +88,7 @@
 
 _frr_daemons = ['zebra', 'bgpd', 'fabricd', 'isisd', 'ospf6d', 'ospfd', 'pbrd',
                 'pimd', 'ripd', 'ripngd', 'sharpd', 'staticd', 'vrrpd', 'ldpd',
-                'bfdd', 'eigrpd', 'babeld']
+                'bfdd', 'eigrpd', 'babeld' ,'pim6d']
 
 path_vtysh = '/usr/bin/vtysh'
 path_frr_reload = '/usr/lib/frr/frr-reload.py'

smoketest/scripts/cli/test_protocols_pimv6.py

@@ -0,0 +1,124 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 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 unittest
+
+from base_vyostest_shim import VyOSUnitTestSHIM
+from vyos.configsession import ConfigSessionError
+from vyos.ifconfig import Section
+from vyos.utils.process import process_named_running
+
+PROCESS_NAME = 'pim6d'
+base_path = ['protocols', 'pimv6']
+
+
+class TestProtocolsPIMv6(VyOSUnitTestSHIM.TestCase):
+    def tearDown(self):
+        # Check for running process
+        self.assertTrue(process_named_running(PROCESS_NAME))
+        self.cli_delete(base_path)
+        self.cli_commit()
+
+    def test_pimv6_01_defaults(self):
+        # commit changes
+        self.cli_set(base_path)
+        self.cli_commit()
+
+        interfaces = Section.interfaces('ethernet')
+
+        # Verify FRR pim6d configuration
+        for interface in interfaces:
+            config = self.getFRRconfig(
+                f'interface {interface}', daemon=PROCESS_NAME)
+            self.assertIn(f'interface {interface}', config)
+            self.assertNotIn(f' ipv6 mld', config)
+
+    def test_pimv6_02_mld_simple(self):
+        # commit changes
+        interfaces = Section.interfaces('ethernet')
+
+        for interface in interfaces:
+            self.cli_set(base_path + ['interface', interface])
+
+        self.cli_commit()
+
+        # Verify FRR pim6d configuration
+        for interface in interfaces:
+            config = self.getFRRconfig(
+                f'interface {interface}', daemon=PROCESS_NAME)
+            self.assertIn(f'interface {interface}', config)
+            self.assertIn(f' ipv6 mld', config)
+            self.assertNotIn(f' ipv6 mld version 1', config)
+
+        # Change to MLD version 1
+        for interface in interfaces:
+            self.cli_set(base_path + ['interface',
+                         interface, 'mld', 'version', '1'])
+
+        self.cli_commit()
+
+        # Verify FRR pim6d configuration
+        for interface in interfaces:
+            config = self.getFRRconfig(
+                f'interface {interface}', daemon=PROCESS_NAME)
+            self.assertIn(f'interface {interface}', config)
+            self.assertIn(f' ipv6 mld', config)
+            self.assertIn(f' ipv6 mld version 1', config)
+
+    def test_pimv6_03_mld_join(self):
+        # commit changes
+        interfaces = Section.interfaces('ethernet')
+
+        # Use an invalid multiple group address
+        for interface in interfaces:
+            self.cli_set(base_path + ['interface',
+                         interface, 'mld', 'join', 'fd00::1234'])
+
+        with self.assertRaises(ConfigSessionError):
+            self.cli_commit()
+        self.cli_delete(base_path + ['interface'])
+
+        # Use a valid multiple group address
+        for interface in interfaces:
+            self.cli_set(base_path + ['interface',
+                         interface, 'mld', 'join', 'ff18::1234'])
+
+        self.cli_commit()
+
+        # Verify FRR pim6d configuration
+        for interface in interfaces:
+            config = self.getFRRconfig(
+                f'interface {interface}', daemon=PROCESS_NAME)
+            self.assertIn(f'interface {interface}', config)
+            self.assertIn(f' ipv6 mld join ff18::1234', config)
+
+        # Join a source-specific multicast group
+        for interface in interfaces:
+            self.cli_set(base_path + ['interface', interface,
+                         'mld', 'join', 'ff38::5678', '2001:db8::5678'])
+
+        self.cli_commit()
+
+        # Verify FRR pim6d configuration
+        for interface in interfaces:
+            config = self.getFRRconfig(
+                f'interface {interface}', daemon=PROCESS_NAME)
+            self.assertIn(f'interface {interface}', config)
+            self.assertIn(f' ipv6 mld join ff38::5678 2001:db8::5678', config)
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)

src/conf_mode/protocols_pimv6.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 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/>.
+
+from ipaddress import IPv6Address
+from sys import exit
+from typing import Optional
+
+from vyos import ConfigError, airbag, frr
+from vyos.config import Config, ConfigDict
+from vyos.configdict import node_changed
+from vyos.configverify import verify_interface_exists
+from vyos.template import render_to_string
+
+airbag.enable()
+
+
+def get_config(config: Optional[Config] = None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['protocols', 'pimv6']
+    pimv6 = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                 get_first_key=True, with_recursive_defaults=True)
+
+    # FRR has VRF support for different routing daemons. As interfaces belong
+    # to VRFs - or the global VRF, we need to check for changed interfaces so
+    # that they will be properly rendered for the FRR config. Also this eases
+    # removal of interfaces from the running configuration.
+    interfaces_removed = node_changed(conf, base + ['interface'])
+    if interfaces_removed:
+        pimv6['interface_removed'] = list(interfaces_removed)
+
+    return pimv6
+
+
+def verify(pimv6: Optional[ConfigDict]):
+    if pimv6 is None:
+        return
+
+    for interface, interface_config in pimv6.get('interface', {}).items():
+        verify_interface_exists(interface)
+        if 'mld' in interface_config:
+            mld = interface_config['mld']
+            for group in mld.get('join', {}).keys():
+                # Validate multicast group address
+                if not IPv6Address(group).is_multicast:
+                    raise ConfigError(f"{group} is not a multicast group")
+
+
+def generate(pimv6: Optional[ConfigDict]):
+    if pimv6 is None:
+        return
+
+    pimv6['new_frr_config'] = render_to_string('frr/pim6d.frr.j2', pimv6)
+
+
+def apply(pimv6: Optional[ConfigDict]):
+    if pimv6 is None:
+        return
+
+    pim6_daemon = 'pim6d'
+
+    # Save original configuration prior to starting any commit actions
+    frr_cfg = frr.FRRConfig()
+
+    frr_cfg.load_configuration(pim6_daemon)
+
+    for key in ['interface', 'interface_removed']:
+        if key not in pimv6:
+            continue
+        for interface in pimv6[key]:
+            frr_cfg.modify_section(
+                f'^interface {interface}', stop_pattern='^exit', remove_stop_mark=True)
+
+    if 'new_frr_config' in pimv6:
+        frr_cfg.add_before(frr.default_add_before, pimv6['new_frr_config'])
+    frr_cfg.commit_configuration(pim6_daemon)
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)