sla: T4222: Add OWAMP and TWAMP for service sla

OWAMP is a command line client application and a policy daemon used
to determine one way latencies between hosts.
OWAMP session control uses traditional client-server communication
between a control-client and a server,
TWAMP (two-way active measurement protocol)
Add configuration and operation modes

set service sla owamp-server
set service sla twamp-server
run force owping 192.0.2.120
run force twping 192.0.2.190

1 files changed, 113 insertions, 0 deletions

diff --git a/src/conf_mode/service_sla.py b/src/conf_mode/service_sla.py
new file mode 100755
index 000000000..e7c3ca59c
--- /dev/null
+++ b/src/conf_mode/service_sla.py
@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 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 sys import exit
+
+from vyos.config import Config
+from vyos.configdict import dict_merge
+from vyos.template import render
+from vyos.util import call
+from vyos.xml import defaults
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+
+owamp_config_dir = '/etc/owamp-server'
+owamp_config_file = f'{owamp_config_dir}/owamp-server.conf'
+systemd_override_owamp = r'/etc/systemd/system/owamp-server.d/20-override.conf'
+
+twamp_config_dir = '/etc/twamp-server'
+twamp_config_file = f'{twamp_config_dir}/twamp-server.conf'
+systemd_override_twamp = r'/etc/systemd/system/twamp-server.d/20-override.conf'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['service', 'sla']
+    if not conf.exists(base):
+        return None
+
+    sla = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True)
+    # We have gathered the dict representation of the CLI, but there are default
+    # options which we need to update into the dictionary retrived.
+    default_values = defaults(base)
+    sla = dict_merge(default_values, sla)
+
+    # Ignore default XML values if config doesn't exists
+    # Delete key from dict
+    if not conf.exists(base + ['owamp-server']):
+        del sla['owamp_server']
+    if not conf.exists(base + ['twamp-server']):
+        del sla['twamp_server']
+
+    return sla
+
+def verify(sla):
+    if not sla:
+        return None
+
+def generate(sla):
+    if not sla:
+        return None
+
+    render(owamp_config_file, 'sla/owamp-server.conf.j2', sla)
+    render(systemd_override_owamp, 'sla/owamp-override.conf.j2', sla)
+
+    render(twamp_config_file, 'sla/twamp-server.conf.j2', sla)
+    render(systemd_override_twamp, 'sla/twamp-override.conf.j2', sla)
+
+    return None
+
+def apply(sla):
+    owamp_service = 'owamp-server.service'
+    twamp_service = 'twamp-server.service'
+
+    call('systemctl daemon-reload')
+
+    if not sla or 'owamp_server' not in sla:
+        call(f'systemctl stop {owamp_service}')
+
+        if os.path.exists(owamp_config_file):
+            os.unlink(owamp_config_file)
+
+    if not sla or 'twamp_server' not in sla:
+        call(f'systemctl stop {twamp_service}')
+        if os.path.exists(twamp_config_file):
+            os.unlink(twamp_config_file)
+
+    if sla and 'owamp_server' in sla:
+        call(f'systemctl reload-or-restart {owamp_service}')
+
+    if sla and 'twamp_server' in sla:
+        call(f'systemctl reload-or-restart {twamp_service}')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)