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
new file mode 100755
index 000000000..e81135a74
--- /dev/null
+++ b/src/conf_mode/policy-route-interface.py
@@ -0,0 +1,120 @@
+#!/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)