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-rwxr-xr-xsrc/conf_mode/policy-route-interface.py120
1 files changed, 120 insertions, 0 deletions
diff --git a/src/conf_mode/policy-route-interface.py b/src/conf_mode/policy-route-interface.py
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+++ b/src/conf_mode/policy-route-interface.py
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+#!/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 sys import argv
+from sys import exit
+
+from vyos.config import Config
+from vyos.ifconfig import Section
+from vyos.template import render
+from vyos.util import cmd
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+def get_config(config=None):
+ if config:
+ conf = config
+ else:
+ conf = Config()
+
+ ifname = argv[1]
+ ifpath = Section.get_config_path(ifname)
+ if_policy_path = f'interfaces {ifpath} policy'
+
+ if_policy = conf.get_config_dict(if_policy_path, key_mangling=('-', '_'), get_first_key=True,
+ no_tag_node_value_mangle=True)
+
+ if_policy['ifname'] = ifname
+ if_policy['policy'] = conf.get_config_dict(['policy'], key_mangling=('-', '_'), get_first_key=True,
+ no_tag_node_value_mangle=True)
+
+ return if_policy
+
+def verify(if_policy):
+ # bail out early - looks like removal from running config
+ if not if_policy:
+ return None
+
+ for route in ['route', 'ipv6_route']:
+ if route in if_policy:
+ if route not in if_policy['policy']:
+ raise ConfigError('Policy route not configured')
+
+ route_name = if_policy[route]
+
+ if route_name not in if_policy['policy'][route]:
+ raise ConfigError(f'Invalid policy route name "{name}"')
+
+ return None
+
+def generate(if_policy):
+ return None
+
+def cleanup_rule(table, chain, ifname, new_name=None):
+ results = cmd(f'nft -a list chain {table} {chain}').split("\n")
+ retval = None
+ for line in results:
+ if f'oifname "{ifname}"' in line:
+ if new_name and f'jump {new_name}' in line:
+ # new_name is used to clear rules for any previously referenced chains
+ # returns true when rule exists and doesn't need to be created
+ retval = True
+ continue
+
+ handle_search = re.search('handle (\d+)', line)
+ if handle_search:
+ cmd(f'nft delete rule {table} {chain} handle {handle_search[1]}')
+ return retval
+
+def apply(if_policy):
+ ifname = if_policy['ifname']
+
+ route_chain = 'VYOS_PBR_PREROUTING'
+ ipv6_route_chain = 'VYOS_PBR6_PREROUTING'
+
+ if 'route' in if_policy:
+ name = 'VYOS_PBR_' + if_policy['route']
+ rule_exists = cleanup_rule('ip mangle', route_chain, ifname, name)
+
+ if not rule_exists:
+ cmd(f'nft insert rule ip mangle {route_chain} iifname {ifname} counter jump {name}')
+ else:
+ cleanup_rule('ip mangle', route_chain, ifname)
+
+ if 'ipv6_route' in if_policy:
+ name = 'VYOS_PBR6_' + if_policy['ipv6_route']
+ rule_exists = cleanup_rule('ip6 mangle', ipv6_route_chain, ifname, name)
+
+ if not rule_exists:
+ cmd(f'nft insert rule ip6 mangle {ipv6_route_chain} iifname {ifname} counter jump {name}')
+ else:
+ cleanup_rule('ip6 mangle', ipv6_route_chain, ifname)
+
+ return None
+
+if __name__ == '__main__':
+ try:
+ c = get_config()
+ verify(c)
+ generate(c)
+ apply(c)
+ except ConfigError as e:
+ print(e)
+ exit(1)