T5171: Rewrite load-balancing wan to XML and python3

Use XML and python3 for 'load-balancing wan'
Use Jinja2 templates instead of old vyatta-wanloadbalance.pl to
generate configuration '/run/load-balance/wlb.conf' wich used by
/opt/vyatta/sbin/wan_lb

1 files changed, 123 insertions, 8 deletions

diff --git a/src/conf_mode/load-balancing-wan.py b/src/conf_mode/load-balancing-wan.py
index 11840249f..2f0cf1293 100755
--- a/src/conf_mode/load-balancing-wan.py
+++ b/src/conf_mode/load-balancing-wan.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2022 VyOS maintainers and contributors
+# 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
@@ -14,17 +14,24 @@
 # 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.configdict import node_changed
-from vyos.util import call
+from vyos.configdict import dict_merge
+from vyos.util import cmd
+from vyos.template import render
+from vyos.xml import defaults
 from vyos import ConfigError
-from pprint import pprint
 from vyos import airbag
 airbag.enable()
 
+load_balancing_dir = '/run/load-balance'
+load_balancing_conf_file = f'{load_balancing_dir}/wlb.conf'
+
 
 def get_config(config=None):
     if config:
@@ -33,27 +40,135 @@ def get_config(config=None):
         conf = Config()
 
     base = ['load-balancing', 'wan']
-    lb = conf.get_config_dict(base, get_first_key=True,
-                                       no_tag_node_value_mangle=True)
+    lb = conf.get_config_dict(base,
+                              get_first_key=True,
+                              key_mangling=('-', '_'),
+                              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.
+    default_values = defaults(base)
+    # lb base default values can not be merged here - remove and add them later
+    if 'interface_health' in default_values:
+        del default_values['interface_health']
+    if 'rule' in default_values:
+        del default_values['rule']
+    lb = dict_merge(default_values, lb)
+
+    if 'interface_health' in lb:
+        for iface in lb.get('interface_health'):
+            default_values_iface = defaults(base + ['interface-health'])
+            if 'test' in default_values_iface:
+                del default_values_iface['test']
+            lb['interface_health'][iface] = dict_merge(
+                default_values_iface, lb['interface_health'][iface])
+            if 'test' in lb['interface_health'][iface]:
+                for node_test in lb['interface_health'][iface]['test']:
+                    default_values_test = defaults(base +
+                                                   ['interface-health', 'test'])
+                    lb['interface_health'][iface]['test'][node_test] = dict_merge(
+                            default_values_test,
+                            lb['interface_health'][iface]['test'][node_test])
+
+    if 'rule' in lb:
+        for rule in lb.get('rule'):
+            default_values_rule = defaults(base + ['rule'])
+            if 'interface' in default_values_rule:
+                del default_values_rule['interface']
+            lb['rule'][rule] = dict_merge(default_values_rule, lb['rule'][rule])
+            if not conf.exists(base + ['rule', rule, 'limit']):
+                del lb['rule'][rule]['limit']
+            if 'interface' in lb['rule'][rule]:
+                for iface in lb['rule'][rule]['interface']:
+                    default_values_rule_iface = defaults(base + ['rule', 'interface'])
+                    lb['rule'][rule]['interface'][iface] = dict_merge(default_values_rule_iface, lb['rule'][rule]['interface'][iface])
 
-    pprint(lb)
     return lb
 
+
 def verify(lb):
-    return None
+    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('sudo /opt/vyatta/sbin/vyatta-wanloadbalance.init stop')
+        except Exception as e:
+            print(f"Error message: {e}")
+
+    else:
+        cmd('sudo sysctl -w net.netfilter.nf_conntrack_acct=1')
+        cmd(f'sudo /opt/vyatta/sbin/vyatta-wanloadbalance.init restart {load_balancing_conf_file}')
 
     return None
 
+
 if __name__ == '__main__':
     try:
         c = get_config()