summaryrefslogtreecommitdiff
path: root/src/conf_mode/policy-route.py
diff options
context:
space:
mode:
Diffstat (limited to 'src/conf_mode/policy-route.py')
-rwxr-xr-xsrc/conf_mode/policy-route.py257
1 files changed, 257 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..82f668acf
--- /dev/null
+++ b/src/conf_mode/policy-route.py
@@ -0,0 +1,257 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 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 re
+
+from json import loads
+from sys import exit
+
+from vyos.config import Config
+from vyos.template import render
+from vyos.util import cmd
+from vyos.util import dict_search_args
+from vyos.util import run
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+mark_offset = 0x7FFFFFFF
+nftables_conf = '/run/nftables_policy.conf'
+
+preserve_chains = [
+ 'VYOS_PBR_PREROUTING',
+ 'VYOS_PBR_POSTROUTING',
+ 'VYOS_PBR6_PREROUTING',
+ 'VYOS_PBR6_POSTROUTING'
+]
+
+valid_groups = [
+ 'address_group',
+ 'network_group',
+ 'port_group'
+]
+
+def get_policy_interfaces(conf):
+ out = {}
+ interfaces = conf.get_config_dict(['interfaces'], key_mangling=('-', '_'), get_first_key=True,
+ no_tag_node_value_mangle=True)
+ def find_interfaces(iftype_conf, output={}, prefix=''):
+ for ifname, if_conf in iftype_conf.items():
+ if 'policy' in if_conf:
+ output[prefix + ifname] = if_conf['policy']
+ for vif in ['vif', 'vif_s', 'vif_c']:
+ if vif in if_conf:
+ output.update(find_interfaces(if_conf[vif], output, f'{prefix}{ifname}.'))
+ return output
+ for iftype, iftype_conf in interfaces.items():
+ out.update(find_interfaces(iftype_conf))
+ return out
+
+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)
+ policy['interfaces'] = get_policy_interfaces(conf)
+
+ return policy
+
+def verify_rule(policy, name, rule_conf, ipv6):
+ 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 {'address_group', 'network_group'} <= set(side_conf['group']):
+ raise ConfigError('Only one address-group or network-group can be specified')
+
+ for group in valid_groups:
+ if group in side_conf['group']:
+ group_name = side_conf['group'][group]
+ 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:
+ print(f'WARNING: {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)
+
+ for ifname, if_policy in policy['interfaces'].items():
+ name = dict_search_args(if_policy, 'route')
+ ipv6_name = dict_search_args(if_policy, 'route6')
+
+ if name and not dict_search_args(policy, 'route', name):
+ raise ConfigError(f'Policy route "{name}" is still referenced on interface {ifname}')
+
+ if ipv6_name and not dict_search_args(policy, 'route6', ipv6_name):
+ raise ConfigError(f'Policy route6 "{ipv6_name}" is still referenced on interface {ifname}')
+
+ return None
+
+def cleanup_rule(table, jump_chain):
+ commands = []
+ results = cmd(f'nft -a list table {table}').split("\n")
+ for line in results:
+ if f'jump {jump_chain}' in line:
+ handle_search = re.search('handle (\d+)', line)
+ if handle_search:
+ commands.append(f'delete rule {table} {chain} handle {handle_search[1]}')
+ return commands
+
+def cleanup_commands(policy):
+ commands = []
+ for table in ['ip mangle', 'ip6 mangle']:
+ json_str = cmd(f'nft -j list table {table}')
+ obj = loads(json_str)
+ if 'nftables' not in obj:
+ continue
+ for item in obj['nftables']:
+ if 'chain' in item:
+ chain = item['chain']['name']
+ if not chain.startswith("VYOS_PBR"):
+ continue
+ if chain not in preserve_chains:
+ if table == 'ip mangle' and dict_search_args(policy, 'route', chain.replace("VYOS_PBR_", "", 1)):
+ commands.append(f'flush chain {table} {chain}')
+ elif table == 'ip6 mangle' and dict_search_args(policy, 'route6', chain.replace("VYOS_PBR6_", "", 1)):
+ commands.append(f'flush chain {table} {chain}')
+ else:
+ commands += cleanup_rule(table, chain)
+ commands.append(f'delete chain {table} {chain}')
+ return commands
+
+def generate(policy):
+ if not os.path.exists(nftables_conf):
+ policy['first_install'] = True
+ else:
+ policy['cleanup_commands'] = cleanup_commands(policy)
+
+ render(nftables_conf, 'firewall/nftables-policy.tmpl', 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)