From b71a04811bd61e1faf2bc4eaceaaae8bdbf97dc6 Mon Sep 17 00:00:00 2001
From: Henning Surmeier <me@hensur.de>
Date: Fri, 28 Jan 2022 17:28:32 +0100
Subject: backport: policy: T4151: remove all previous rules on edit

---
 src/conf_mode/policy-local-route.py | 47 ++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 9 deletions(-)

(limited to 'src')

diff --git a/src/conf_mode/policy-local-route.py b/src/conf_mode/policy-local-route.py
index 1fcd3db2e..c4bef3414 100755
--- a/src/conf_mode/policy-local-route.py
+++ b/src/conf_mode/policy-local-route.py
@@ -69,20 +69,47 @@ def get_config(config=None):
         # delete policy local-route rule x fwmark x
         # delete policy local-route rule x destination x.x.x.x
         if 'rule' in pbr[route]:
-            for rule in pbr[route]['rule']:
+            for rule, rule_config in pbr[route]['rule'].items():
                 src = leaf_node_changed(conf, base_rule + [rule, 'source'])
                 fwmk = leaf_node_changed(conf, base_rule + [rule, 'fwmark'])
                 dst = leaf_node_changed(conf, base_rule + [rule, 'destination'])
+                # keep track of changes in configuration
+                # otherwise we might remove an existing node although nothing else has changed
+                changed = False
 
                 rule_def = {}
-                if src:
-                    rule_def = dict_merge({'source' : src}, rule_def)
-                if fwmk:
-                    rule_def = dict_merge({'fwmark' : fwmk}, rule_def)
-                if dst:
-                    rule_def = dict_merge({'destination' : dst}, rule_def)
-                dict = dict_merge({dict_id : {rule : rule_def}}, dict)
-                pbr.update(dict)
+                # src is None if there are no changes to src
+                if src is None:
+                    # if src hasn't changed, include it in the removal selector
+                    # if a new selector is added, we have to remove all previous rules without this selector
+                    # to make sure we remove all previous rules with this source(s), it will be included
+                    if 'source' in rule_config:
+                        rule_def = dict_merge({'source': rule_config['source']}, rule_def)
+                else:
+                    # if src is not None, it's previous content will be returned
+                    # this can be an empty array if it's just being set, or the previous value
+                    # either way, something has to be changed and we only want to remove previous values
+                    changed = True
+                    # set the old value for removal if it's not empty
+                    if len(src) > 0:
+                        rule_def = dict_merge({'source' : src}, rule_def)
+                if fwmk is None:
+                    if 'fwmark' in rule_config:
+                        rule_def = dict_merge({'fwmark': rule_config['fwmark']}, rule_def)
+                else:
+                    changed = True
+                    if len(fwmk) > 0:
+                        rule_def = dict_merge({'fwmark' : fwmk}, rule_def)
+                if dst is None:
+                    if 'destination' in rule_config:
+                        rule_def = dict_merge({'destination': rule_config['destination']}, rule_def)
+                else:
+                    changed = True
+                    if len(dst) > 0:
+                        rule_def = dict_merge({'destination' : dst}, rule_def)
+                if changed:
+                    dict = dict_merge({dict_id : {rule : rule_def}}, dict)
+                    pbr.update(dict)
 
     return pbr
 
@@ -116,6 +143,8 @@ def apply(pbr):
     if not pbr:
         return None
 
+    print(pbr)
+
     # Delete old rule if needed
     for rule_rm in ['rule_remove', 'rule6_remove']:
         if rule_rm in pbr:
-- 
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