Merge pull request #2730 from vyos/mergify/bp/sagitta/pr-2729

T5474: establish common file name pattern for XML conf mode commands (backport #2729)

1 files changed, 195 insertions, 0 deletions

diff --git a/src/conf_mode/policy_route.py b/src/conf_mode/policy_route.py
new file mode 100755
index 000000000..adad012de
--- /dev/null
+++ b/src/conf_mode/policy_route.py
@@ -0,0 +1,195 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021-2023 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 json import loads
+from sys import exit
+
+from vyos.base import Warning
+from vyos.config import Config
+from vyos.template import render
+from vyos.utils.dict import dict_search_args
+from vyos.utils.process import cmd
+from vyos.utils.process import run
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+mark_offset = 0x7FFFFFFF
+nftables_conf = '/run/nftables_policy.conf'
+
+valid_groups = [
+    'address_group',
+    'domain_group',
+    'network_group',
+    'port_group',
+    'interface_group'
+]
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['policy']
+
+    policy = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True,
+                                    no_tag_node_value_mangle=True)
+
+    policy['firewall_group'] = conf.get_config_dict(['firewall', 'group'], key_mangling=('-', '_'), get_first_key=True,
+                                    no_tag_node_value_mangle=True)
+
+    return policy
+
+def verify_rule(policy, name, rule_conf, ipv6, rule_id):
+    icmp = 'icmp' if not ipv6 else 'icmpv6'
+    if icmp in rule_conf:
+        icmp_defined = False
+        if 'type_name' in rule_conf[icmp]:
+            icmp_defined = True
+            if 'code' in rule_conf[icmp] or 'type' in rule_conf[icmp]:
+                raise ConfigError(f'{name} rule {rule_id}: Cannot use ICMP type/code with ICMP type-name')
+        if 'code' in rule_conf[icmp]:
+            icmp_defined = True
+            if 'type' not in rule_conf[icmp]:
+                raise ConfigError(f'{name} rule {rule_id}: ICMP code can only be defined if ICMP type is defined')
+        if 'type' in rule_conf[icmp]:
+            icmp_defined = True
+
+        if icmp_defined and 'protocol' not in rule_conf or rule_conf['protocol'] != icmp:
+            raise ConfigError(f'{name} rule {rule_id}: ICMP type/code or type-name can only be defined if protocol is ICMP')
+
+    if 'set' in rule_conf:
+        if 'tcp_mss' in rule_conf['set']:
+            tcp_flags = dict_search_args(rule_conf, 'tcp', 'flags')
+            if not tcp_flags or 'syn' not in tcp_flags:
+                raise ConfigError(f'{name} rule {rule_id}: TCP SYN flag must be set to modify TCP-MSS')
+
+    tcp_flags = dict_search_args(rule_conf, 'tcp', 'flags')
+    if tcp_flags:
+        if dict_search_args(rule_conf, 'protocol') != 'tcp':
+            raise ConfigError('Protocol must be tcp when specifying tcp flags')
+
+        not_flags = dict_search_args(rule_conf, 'tcp', 'flags', 'not')
+        if not_flags:
+            duplicates = [flag for flag in tcp_flags if flag in not_flags]
+            if duplicates:
+                raise ConfigError(f'Cannot match a tcp flag as set and not set')
+
+    for side in ['destination', 'source']:
+        if side in rule_conf:
+            side_conf = rule_conf[side]
+
+            if 'group' in side_conf:
+                if len({'address_group', 'domain_group', 'network_group'} & set(side_conf['group'])) > 1:
+                    raise ConfigError('Only one address-group, domain-group or network-group can be specified')
+
+                for group in valid_groups:
+                    if group in side_conf['group']:
+                        group_name = side_conf['group'][group]
+
+                        if group_name.startswith('!'):
+                            group_name = group_name[1:]
+
+                        fw_group = f'ipv6_{group}' if ipv6 and group in ['address_group', 'network_group'] else group
+                        error_group = fw_group.replace("_", "-")
+                        group_obj = dict_search_args(policy['firewall_group'], fw_group, group_name)
+
+                        if group_obj is None:
+                            raise ConfigError(f'Invalid {error_group} "{group_name}" on policy route rule')
+
+                        if not group_obj:
+                            Warning(f'{error_group} "{group_name}" has no members')
+
+            if 'port' in side_conf or dict_search_args(side_conf, 'group', 'port_group'):
+                if 'protocol' not in rule_conf:
+                    raise ConfigError('Protocol must be defined if specifying a port or port-group')
+
+                if rule_conf['protocol'] not in ['tcp', 'udp', 'tcp_udp']:
+                    raise ConfigError('Protocol must be tcp, udp, or tcp_udp when specifying a port or port-group')
+
+def verify(policy):
+    for route in ['route', 'route6']:
+        ipv6 = route == 'route6'
+        if route in policy:
+            for name, pol_conf in policy[route].items():
+                if 'rule' in pol_conf:
+                    for rule_id, rule_conf in pol_conf['rule'].items():
+                        verify_rule(policy, name, rule_conf, ipv6, rule_id)
+
+    return None
+
+def generate(policy):
+    if not os.path.exists(nftables_conf):
+        policy['first_install'] = True
+
+    render(nftables_conf, 'firewall/nftables-policy.j2', policy)
+    return None
+
+def apply_table_marks(policy):
+    for route in ['route', 'route6']:
+        if route in policy:
+            cmd_str = 'ip' if route == 'route' else 'ip -6'
+            tables = []
+            for name, pol_conf in policy[route].items():
+                if 'rule' in pol_conf:
+                    for rule_id, rule_conf in pol_conf['rule'].items():
+                        set_table = dict_search_args(rule_conf, 'set', 'table')
+                        if set_table:
+                            if set_table == 'main':
+                                set_table = '254'
+                            if set_table in tables:
+                                continue
+                            tables.append(set_table)
+                            table_mark = mark_offset - int(set_table)
+                            cmd(f'{cmd_str} rule add pref {set_table} fwmark {table_mark} table {set_table}')
+
+def cleanup_table_marks():
+    for cmd_str in ['ip', 'ip -6']:
+        json_rules = cmd(f'{cmd_str} -j -N rule list')
+        rules = loads(json_rules)
+        for rule in rules:
+            if 'fwmark' not in rule or 'table' not in rule:
+                continue
+            fwmark = rule['fwmark']
+            table = int(rule['table'])
+            if fwmark[:2] == '0x':
+                fwmark = int(fwmark, 16)
+            if (int(fwmark) == (mark_offset - table)):
+                cmd(f'{cmd_str} rule del fwmark {fwmark} table {table}')
+
+def apply(policy):
+    install_result = run(f'nft -f {nftables_conf}')
+    if install_result == 1:
+        raise ConfigError('Failed to apply policy based routing')
+
+    if 'first_install' not in policy:
+        cleanup_table_marks()
+
+    apply_table_marks(policy)
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)