ifconfig: T6972: smoketests fail as IP address is not removed in time

From time to time integration tests fail as the DHCP assigned IP address is not
removed in time then dhclient stops. Add an explicit code path cleaning dynamic
assigned addresses from interface when disabling DHCP - if such a dynamic
address is remaining.

======================================================================
FAIL: test_dhcp_vrf (__main__.EthernetInterfaceTest.test_dhcp_vrf)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/libexec/vyos/tests/smoke/cli/test_interfaces_ethernet.py", line 72, in tearDown
    self.assertNotIn(AF_INET, ifaddresses(interface))
AssertionError: 2 unexpectedly found in {17: [{'addr': '52:54:00:00:00:00',
  'broadcast': 'ff:ff:ff:ff:ff:ff'}], 2: [{'addr': '192.0.2.103', 'netmask': '255.255.255.0',
  'broadcast': '192.0.2.255'}], 10: [{'addr': 'fe80::5054:ff:fe00:0%eth0',
  'netmask': 'ffff:ffff:ffff:ffff::/64'}]}

1 files changed, 21 insertions, 6 deletions

diff --git a/python/vyos/ifconfig/interface.py b/python/vyos/ifconfig/interface.py
index eac9f61f5..cad1685a9 100644
--- a/python/vyos/ifconfig/interface.py
+++ b/python/vyos/ifconfig/interface.py
@@ -29,6 +29,7 @@ from netifaces import AF_INET6
 from netaddr import EUI
 from netaddr import mac_unix_expanded
 
+from vyos.base import ConfigError
 from vyos.configdict import list_diff
 from vyos.configdict import dict_merge
 from vyos.configdict import get_vlan_ids
@@ -43,6 +44,7 @@ from vyos.template import render
 from vyos.utils.network import mac2eui64
 from vyos.utils.dict import dict_search
 from vyos.utils.network import get_interface_config
+from vyos.utils.network import get_interface_address
 from vyos.utils.network import get_interface_namespace
 from vyos.utils.network import get_vrf_tableid
 from vyos.utils.network import is_netns_interface
@@ -62,7 +64,6 @@ from vyos.ifconfig.control import Control
 from vyos.ifconfig.vrrp import VRRP
 from vyos.ifconfig.operational import Operational
 from vyos.ifconfig import Section
-from vyos import ConfigError
 
 link_local_prefix = 'fe80::/64'
 
@@ -1375,12 +1376,11 @@ class Interface(Control):
         if enable not in [True, False]:
             raise ValueError()
 
-        ifname = self.ifname
         config_base = directories['isc_dhclient_dir'] + '/dhclient'
-        dhclient_config_file = f'{config_base}_{ifname}.conf'
-        dhclient_lease_file = f'{config_base}_{ifname}.leases'
-        systemd_override_file = f'/run/systemd/system/dhclient@{ifname}.service.d/10-override.conf'
-        systemd_service = f'dhclient@{ifname}.service'
+        dhclient_config_file = f'{config_base}_{self.ifname}.conf'
+        dhclient_lease_file = f'{config_base}_{self.ifname}.leases'
+        systemd_override_file = f'/run/systemd/system/dhclient@{self.ifname}.service.d/10-override.conf'
+        systemd_service = f'dhclient@{self.ifname}.service'
 
         # Rendered client configuration files require the apsolute config path
         self.config['isc_dhclient_dir'] = directories['isc_dhclient_dir']
@@ -1414,6 +1414,21 @@ class Interface(Control):
         else:
             if is_systemd_service_active(systemd_service):
                 self._cmd(f'systemctl stop {systemd_service}')
+
+            # Smoketests occationally fail if the lease is not removed from the Kernel fast enough:
+            # AssertionError: 2 unexpectedly found in {17: [{'addr': '52:54:00:00:00:00',
+            # 'broadcast': 'ff:ff:ff:ff:ff:ff'}], 2: [{'addr': '192.0.2.103', 'netmask': '255.255.255.0',
+            #
+            # We will force removal of any dynamic IPv4 address from the interface
+            tmp = get_interface_address(self.ifname)
+            if tmp and 'addr_info' in tmp:
+                for address_dict in tmp['addr_info']:
+                    # Only remove dynamic assigned addresses
+                    if 'dynamic' not in address_dict:
+                        continue
+                    address = address_dict['local']
+                    self.del_addr(address)
+
             # cleanup old config files
             for file in [dhclient_config_file, systemd_override_file, dhclient_lease_file]:
                 if os.path.isfile(file):