Merge pull request #5469 from c-po/q-in-q-removal

ifconfig: T9313: fix removal of QinQ sub-interfaces

2 files changed, 19 insertions, 8 deletions

diff --git a/python/vyos/ifconfig/ethernet.py b/python/vyos/ifconfig/ethernet.py
index 1b10d075e..ab5c8a0b8 100644
--- a/python/vyos/ifconfig/ethernet.py
+++ b/python/vyos/ifconfig/ethernet.py
@@ -19,7 +19,6 @@ from glob import glob
 
 from vyos.base import Warning
 from vyos.ethtool import Ethtool
-from vyos.ifconfig import Section
 from vyos.ifconfig.interface import Interface
 from vyos.utils.dict import dict_search
 from vyos.utils.file import read_file
@@ -136,19 +135,17 @@ class EthernetIf(Interface):
         >>> i.remove()
         """
 
-        # T7813: we do need to remove the VLAN subinterfaces first so we can
-        # properly stop the DHCP client and inform the DHCP server that we are
-        # returning the lease.
-        for vlan in Section.sub_interfaces(self.ifname):
-            Interface(vlan).remove()
+        # T7813: the base class removes all VLAN sub-interfaces and flushes the
+        # addresses of this interface - both require a link which is still up so
+        # a DHCP client can return its lease. A physical interface is "eternal"
+        # and thus survives this call.
+        super().remove()
 
         if self.exists(self.ifname):
             # interface is placed in A/D state when removed from config! It
             # will remain visible for the operating system.
             self.set_admin_state('down')
 
-        super().remove()
-
     def set_flow_control(self, enable, warn=True):
         """
         Changes the pause parameters of the specified Ethernet device.
diff --git a/python/vyos/ifconfig/interface.py b/python/vyos/ifconfig/interface.py
index 3a5efec8c..73f7544dd 100644
--- a/python/vyos/ifconfig/interface.py
+++ b/python/vyos/ifconfig/interface.py
@@ -393,6 +393,20 @@ class Interface(Control):
         >>> i = Interface('eth0')
         >>> i.remove()
         """
+        # T7813: VLAN sub-interfaces must be de-configured before this interface
+        # is torn down, otherwise a running DHCP client can neither talk to the
+        # server nor return its lease. Deleting an interface implicitly deletes
+        # all its VLAN children in the Kernel, thus start with the deepest
+        # interface (vif-c) and work the way up to the vif interfaces.
+        for vlan in sorted(
+            Section.sub_interfaces(self.ifname), key=lambda x: x.count('.'), reverse=True
+        ):
+            # A previous iteration may have already removed this interface as a
+            # side effect - do not re-create it when instantiating Interface()
+            if not Interface.exists(vlan):
+                continue
+            Interface(vlan).remove()
+
         # Stop WPA supplicant if EAPoL was in use
         netns = self.config['netns'] if 'netns' in self.config else None
         stop_systemd_unit(f'wpa_supplicant-wired@{self.ifname}', netns=netns)