T6641: Add vyos-network-event-logger Service

The service parses and logs network events for improved monitoring and diagnostics.
Supported event types include:

- `RTM_NEWROUTE`, `RTM_DELROUTE`
- `RTM_NEWLINK`, `RTM_DELLINK`
- `RTM_NEWADDR`, `RTM_DELADDR`
- `RTM_NEWNEIGH`, `RTM_DELNEIGH`, `RTM_GETNEIGH`
- `RTM_NEWRULE`, `RTM_DELRULE`

Added operational mode commands for filtered log retrieval:
- `show log network-event <event-type> <interface>`: Retrieve logs filtered by event type and interface.
- `show interfaces <type> <name> event-log <event-type>`: Display interface-specific logs filtered by event type.

1 files changed, 93 insertions, 0 deletions

diff --git a/src/conf_mode/service_monitoring_network_event.py b/src/conf_mode/service_monitoring_network_event.py
new file mode 100644
index 000000000..104e6ce23
--- /dev/null
+++ b/src/conf_mode/service_monitoring_network_event.py
@@ -0,0 +1,93 @@
+#!/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 os
+import json
+
+from sys import exit
+
+from vyos.config import Config
+from vyos.utils.file import write_file
+from vyos.utils.process import call
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+vyos_network_event_logger_config = r'/run/vyos-network-event-logger.conf'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['service', 'monitoring', 'network-event']
+    if not conf.exists(base):
+        return None
+
+    monitoring = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                      get_first_key=True,
+                                      no_tag_node_value_mangle=True)
+
+    # We have gathered the dict representation of the CLI, but there are default
+    # options which we need to update into the dictionary retrived.
+    monitoring = conf.merge_defaults(monitoring, recursive=True)
+
+    return monitoring
+
+
+def verify(monitoring):
+    if not monitoring:
+        return None
+
+    return None
+
+
+def generate(monitoring):
+    if not monitoring:
+        # Delete config
+        if os.path.exists(vyos_network_event_logger_config):
+            os.unlink(vyos_network_event_logger_config)
+
+        return None
+
+    # Create config
+    log_conf_json = json.dumps(monitoring, indent=4)
+    write_file(vyos_network_event_logger_config, log_conf_json)
+
+    return None
+
+
+def apply(monitoring):
+    # Reload systemd manager configuration
+    systemd_service = 'vyos-network-event-logger.service'
+
+    if not monitoring:
+        call(f'systemctl stop {systemd_service}')
+        return
+
+    call(f'systemctl restart {systemd_service}')
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)