ifconfig: T2653: implement update() in derived classes for admin up/down

Every derived class must implement update() to set the interfaces admin
up/down state. This is required to prevend extensive link flaps when e.g.
reconfiguring bond interfaces.

1 files changed, 19 insertions, 0 deletions

diff --git a/python/vyos/ifconfig/dummy.py b/python/vyos/ifconfig/dummy.py
index 404c490c7..43614cd1c 100644
--- a/python/vyos/ifconfig/dummy.py
+++ b/python/vyos/ifconfig/dummy.py
@@ -35,3 +35,22 @@ class DummyIf(Interface):
             'prefixes': ['dum', ],
         },
     }
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)