T5474: establish common file name pattern for XML conf mode commands

We will use _ as CLI level divider. The XML definition filename and also
the Python helper should match the CLI node.

Example:
set interfaces ethernet -> interfaces_ethernet.xml.in
set interfaces bond -> interfaces_bond.xml.in
set service dhcp-server -> service_dhcp-server-xml.in

1 files changed, 151 insertions, 0 deletions

diff --git a/src/conf_mode/load-balancing_wan.py b/src/conf_mode/load-balancing_wan.py
new file mode 100755
index 000000000..5da0b906b
--- /dev/null
+++ b/src/conf_mode/load-balancing_wan.py
@@ -0,0 +1,151 @@
+#!/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 os
+
+from sys import exit
+from shutil import rmtree
+
+from vyos.base import Warning
+from vyos.config import Config
+from vyos.configdep import set_dependents, call_dependents
+from vyos.utils.process import cmd
+from vyos.template import render
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+load_balancing_dir = '/run/load-balance'
+load_balancing_conf_file = f'{load_balancing_dir}/wlb.conf'
+systemd_service = 'vyos-wan-load-balance.service'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+
+    base = ['load-balancing', 'wan']
+    lb = conf.get_config_dict(base, key_mangling=('-', '_'),
+                              no_tag_node_value_mangle=True,
+                              get_first_key=True,
+                              with_recursive_defaults=True)
+
+    # prune limit key if not set by user
+    for rule in lb.get('rule', []):
+        if lb.from_defaults(['rule', rule, 'limit']):
+            del lb['rule'][rule]['limit']
+
+    set_dependents('conntrack', conf)
+
+    return lb
+
+
+def verify(lb):
+    if not lb:
+        return None
+
+    if 'interface_health' not in lb:
+        raise ConfigError(
+            'A valid WAN load-balance configuration requires an interface with a nexthop!'
+        )
+
+    for interface, interface_config in lb['interface_health'].items():
+        if 'nexthop' not in interface_config:
+            raise ConfigError(
+                f'interface-health {interface} nexthop must be specified!')
+
+        if 'test' in interface_config:
+            for test_rule, test_config in interface_config['test'].items():
+                if 'type' in test_config:
+                    if test_config['type'] == 'user-defined' and 'test_script' not in test_config:
+                        raise ConfigError(
+                            f'test {test_rule} script must be defined for test-script!'
+                        )
+
+    if 'rule' not in lb:
+        Warning(
+            'At least one rule with an (outbound) interface must be defined for WAN load balancing to be active!'
+        )
+    else:
+        for rule, rule_config in lb['rule'].items():
+            if 'inbound_interface' not in rule_config:
+                raise ConfigError(f'rule {rule} inbound-interface must be specified!')
+            if {'failover', 'exclude'} <= set(rule_config):
+                raise ConfigError(f'rule {rule} failover cannot be configured with exclude!')
+            if {'limit', 'exclude'} <= set(rule_config):
+                raise ConfigError(f'rule {rule} limit cannot be used with exclude!')
+            if 'interface' not in rule_config:
+                if 'exclude' not in rule_config:
+                    Warning(
+                        f'rule {rule} will be inactive because no (outbound) interfaces have been defined for this rule'
+                    )
+            for direction in {'source', 'destination'}:
+                if direction in rule_config:
+                    if 'protocol' in rule_config and 'port' in rule_config[
+                            direction]:
+                        if rule_config['protocol'] not in {'tcp', 'udp'}:
+                            raise ConfigError('ports can only be specified when protocol is "tcp" or "udp"')
+
+
+def generate(lb):
+    if not lb:
+        # Delete /run/load-balance/wlb.conf
+        if os.path.isfile(load_balancing_conf_file):
+            os.unlink(load_balancing_conf_file)
+        # Delete old directories
+        if os.path.isdir(load_balancing_dir):
+            rmtree(load_balancing_dir, ignore_errors=True)
+        if os.path.exists('/var/run/load-balance/wlb.out'):
+            os.unlink('/var/run/load-balance/wlb.out')
+
+        return None
+
+    # Create load-balance dir
+    if not os.path.isdir(load_balancing_dir):
+        os.mkdir(load_balancing_dir)
+
+    render(load_balancing_conf_file, 'load-balancing/wlb.conf.j2', lb)
+
+    return None
+
+
+def apply(lb):
+    if not lb:
+        try:
+            cmd(f'systemctl stop {systemd_service}')
+        except Exception as e:
+            print(f"Error message: {e}")
+
+    else:
+        cmd('sudo sysctl -w net.netfilter.nf_conntrack_acct=1')
+        cmd(f'systemctl restart {systemd_service}')
+
+    call_dependents()
+
+    return None
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)