router-advert: T2162: bugfix migrating link-mtu nodes with 0 value

... those nodes mean link-mtu advertisement is disabled in radvd and thus we
delete the node completely as it's useless.

2 files changed, 11 insertions, 1 deletions

diff --git a/src/conf_mode/service-router-advert.py b/src/conf_mode/service-router-advert.py
index 5ae719c29..1e0d28397 100755
--- a/src/conf_mode/service-router-advert.py
+++ b/src/conf_mode/service-router-advert.py
@@ -42,7 +42,9 @@ interface {{ i.name }} {
 {% if i.default_lifetime %}
     AdvDefaultLifetime {{ i.default_lifetime }};
 {% endif %}
+{% if i.link_mtu %}
     AdvLinkMTU {{ i.link_mtu }};
+{% endif %}
     AdvOtherConfigFlag {{ i.other_config_flag }};
     AdvRetransTimer {{ i.retrans_timer }};
     AdvCurHopLimit {{ i.hop_limit }};
@@ -81,7 +83,7 @@ def get_config():
             'default_lifetime': '',
             'default_preference': 'medium',
             'dnssl': [],
-            'link_mtu': '0',
+            'link_mtu': '',
             'managed_flag': 'off',
             'interval_max': '600',
             'interval_min': '',
diff --git a/src/migration-scripts/interfaces/5-to-6 b/src/migration-scripts/interfaces/5-to-6
index 9dbfd30e1..85a1994c6 100755
--- a/src/migration-scripts/interfaces/5-to-6
+++ b/src/migration-scripts/interfaces/5-to-6
@@ -75,6 +75,14 @@ def copy_rtradv(c, old_base, interface):
             if tmp == 'false':
                 c.set(new_base + ['no-send-advert'])
 
+        # link-mtu advertisement was formerly disabled by setting its value to 0
+        # ... this makes less sense - if it should not be send, just do not
+        # configure it
+        if c.exists(new_base + ['link-mtu']):
+            tmp = c.return_value(new_base + ['link-mtu'])
+            if tmp == '0':
+                c.delete(new_base + ['link-mtu'])
+
 if __name__ == '__main__':
     if (len(sys.argv) < 1):
         print("Must specify file name!")