op-mode: T5969: list multicast group membership

cpo@LR1.wue3:~$ show ip multicast group interface eth0.201
Interface    Family    Address
-----------  --------  ---------
eth0.201     inet      224.0.0.6
eth0.201     inet      224.0.0.5
eth0.201     inet      224.0.0.1

cpo@LR1.wue3:~$ show ipv6 multicast group interface eth0
Interface    Family    Address
-----------  --------  -----------------
eth0         inet6     ff02::1:ff00:0
eth0         inet6     ff02::1:ffbf:c56d
eth0         inet6     ff05::2
eth0         inet6     ff01::2
eth0         inet6     ff02::2
eth0         inet6     ff02::1
eth0         inet6     ff01::1

1 files changed, 72 insertions, 0 deletions

diff --git a/src/op_mode/multicast.py b/src/op_mode/multicast.py
new file mode 100755
index 000000000..0666f8af3
--- /dev/null
+++ b/src/op_mode/multicast.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2024 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 json
+import sys
+import typing
+
+from tabulate import tabulate
+from vyos.utils.process import cmd
+
+import vyos.opmode
+
+ArgFamily = typing.Literal['inet', 'inet6']
+
+def _get_raw_data(family, interface=None):
+    tmp = 'ip -4'
+    if family == 'inet6':
+        tmp = 'ip -6'
+    tmp = f'{tmp} -j maddr show'
+    if interface:
+        tmp = f'{tmp} dev {interface}'
+    output = cmd(tmp)
+    data = json.loads(output)
+    if not data:
+        return []
+    return data
+
+def _get_formatted_output(raw_data):
+    data_entries = []
+
+    # sort result by interface name
+    for interface in sorted(raw_data, key=lambda x: x['ifname']):
+        for address in interface['maddr']:
+            tmp = []
+            tmp.append(interface['ifname'])
+            tmp.append(address['family'])
+            tmp.append(address['address'])
+
+            data_entries.append(tmp)
+
+    headers = ["Interface", "Family", "Address"]
+    output = tabulate(data_entries, headers, numalign="left")
+    return output
+
+def show_group(raw: bool, family: ArgFamily, interface: typing.Optional[str]):
+    multicast_data = _get_raw_data(family=family, interface=interface)
+    if raw:
+        return multicast_data
+    else:
+        return _get_formatted_output(multicast_data)
+
+if __name__ == "__main__":
+    try:
+        res = vyos.opmode.run(sys.modules[__name__])
+        if res:
+            print(res)
+    except (ValueError, vyos.opmode.Error) as e:
+        print(e)
+        sys.exit(1)