bridge: T2232: move helper to vyos.validate

12 files changed, 136 insertions, 125 deletions

diff --git a/python/vyos/util.py b/python/vyos/util.py
index c70bff091..b1d95fbbf 100644
--- a/python/vyos/util.py
+++ b/python/vyos/util.py
@@ -429,24 +429,6 @@ def mac2eui64(mac, prefix=None):
         except:  # pylint: disable=bare-except
             return
 
-def is_bridge_member(interface):
-    """
-    Checks if passed interfaces is part of a bridge device or not.
-
-    Returns a tuple:
-    False, None -> Not part of a bridge
-    True, bridge-name -> If it is assigned to a bridge
-    """
-    from vyos.config import Config
-    c = Config()
-    base = ['interfaces', 'bridge']
-    for bridge in c.list_nodes(base):
-        members = c.list_nodes(base + [bridge, 'member', 'interface'])
-        if interface in members:
-            return (True, bridge)
-
-    return False, None
-
 def get_half_cpus():
     """ return 1/2 of the numbers of available CPUs """
     cpu = os.cpu_count()
diff --git a/python/vyos/validate.py b/python/vyos/validate.py
index 9d413ffab..15716ada4 100644
--- a/python/vyos/validate.py
+++ b/python/vyos/validate.py
@@ -86,8 +86,8 @@ def _is_intf_addr_assigned(intf, address, netmask=''):
 
     # check if the requested address type is configured at all
     # {
-    # 17: [{'addr': '08:00:27:d9:5b:04', 'broadcast': 'ff:ff:ff:ff:ff:ff'}], 
-    # 2:  [{'addr': '10.0.2.15', 'netmask': '255.255.255.0', 'broadcast': '10.0.2.255'}], 
+    # 17: [{'addr': '08:00:27:d9:5b:04', 'broadcast': 'ff:ff:ff:ff:ff:ff'}],
+    # 2:  [{'addr': '10.0.2.15', 'netmask': '255.255.255.0', 'broadcast': '10.0.2.255'}],
     # 10: [{'addr': 'fe80::a00:27ff:fed9:5b04%eth0', 'netmask': 'ffff:ffff:ffff:ffff::'}]
     # }
     try:
@@ -240,3 +240,28 @@ def assert_mac(m):
 
     if octets[:5] == (0, 0, 94, 0, 1):
         raise ValueError(f'{m} is a VRRP MAC address')
+
+def is_bridge_member(conf, interface):
+    """
+    Checks if passed interfaces is part of a bridge device or not.
+
+    Returns a tuple:
+    None -> Interface not a bridge member
+    Bridge -> Interface is a member of this bridge
+    """
+    ret_val = None
+    old_level = conf.get_level()
+
+    # set config level to root
+    conf.set_level([])
+    base = ['interfaces', 'bridge']
+    for bridge in conf.list_nodes(base):
+        members = conf.list_nodes(base + [bridge, 'member', 'interface'])
+        print(members)
+        if interface in members:
+            ret_val = bridge
+            break
+
+    old_level = conf.set_level(old_level)
+    return ret_val
+
diff --git a/src/conf_mode/interfaces-bonding.py b/src/conf_mode/interfaces-bonding.py
index fd1f218d1..380457772 100755
--- a/src/conf_mode/interfaces-bonding.py
+++ b/src/conf_mode/interfaces-bonding.py
@@ -24,8 +24,8 @@ from vyos.ifconfig import BondIf
 from vyos.ifconfig_vlan import apply_vlan_config, verify_vlan_config
 from vyos.configdict import list_diff, vlan_to_dict
 from vyos.config import Config
-from vyos.util import is_bridge_member
 from vyos.util import call
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 default_config_data = {
@@ -43,6 +43,7 @@ default_config_data = {
     'disable': False,
     'disable_link_detect': 1,
     'hash_policy': 'layer2',
+    'intf': '',
     'ip_arp_cache_tmo': 30,
     'ip_disable_arp_filter': 1,
     'ip_enable_arp_accept': 0,
@@ -54,7 +55,7 @@ default_config_data = {
     'ipv6_eui64_prefix': '',
     'ipv6_forwarding': 1,
     'ipv6_dup_addr_detect': 1,
-    'intf': '',
+    'is_bridge_member': False,
     'mac': '',
     'mode': '802.3ad',
     'member': [],
@@ -109,6 +110,8 @@ def get_config():
     cfg_base = 'interfaces bonding ' + bond['intf']
     if not conf.exists(cfg_base):
         bond['deleted'] = True
+        # check if interface is member if a bridge
+        bond['is_bridge_member'] = is_bridge_member(conf, bond['intf'])
         return bond
 
     # set new configuration level
@@ -279,13 +282,10 @@ def get_config():
 
 def verify(bond):
     if bond['deleted']:
-        interface = bond['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if bond['is_bridge_member']:
+            interface = bond['intf']
+            bridge = bond['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
         return None
 
     if len (bond['arp_mon_tgt']) > 16:
diff --git a/src/conf_mode/interfaces-dummy.py b/src/conf_mode/interfaces-dummy.py
index a256103af..2cc60fb16 100755
--- a/src/conf_mode/interfaces-dummy.py
+++ b/src/conf_mode/interfaces-dummy.py
@@ -23,7 +23,7 @@ from netifaces import interfaces
 from vyos.ifconfig import DummyIf
 from vyos.configdict import list_diff
 from vyos.config import Config
-from vyos.util import is_bridge_member
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 default_config_data = {
@@ -33,6 +33,7 @@ default_config_data = {
     'description': '',
     'disable': False,
     'intf': '',
+    'is_bridge_member': False,
     'vrf': ''
 }
 
@@ -49,6 +50,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists('interfaces dummy ' + dummy['intf']):
         dummy['deleted'] = True
+        # check if interface is member if a bridge
+        dummy['is_bridge_member'] = is_bridge_member(conf, dummy['intf'])
         return dummy
 
     # set new configuration level
@@ -80,13 +83,11 @@ def get_config():
 
 def verify(dummy):
     if dummy['deleted']:
-        interface = dummy['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if dummy['is_bridge_member']::
+            interface = dummy['intf']
+            bridge = dummy['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     vrf_name = dummy['vrf']
diff --git a/src/conf_mode/interfaces-geneve.py b/src/conf_mode/interfaces-geneve.py
index e47473d76..708a64474 100755
--- a/src/conf_mode/interfaces-geneve.py
+++ b/src/conf_mode/interfaces-geneve.py
@@ -22,7 +22,7 @@ from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.ifconfig import GeneveIf
-from vyos.util import is_bridge_member
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 default_config_data = {
@@ -33,6 +33,7 @@ default_config_data = {
     'intf': '',
     'ip_arp_cache_tmo': 30,
     'ip_proxy_arp': 0,
+    'is_bridge_member': False,
     'mtu': 1500,
     'remote': '',
     'vni': ''
@@ -51,6 +52,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists('interfaces geneve ' + geneve['intf']):
         geneve['deleted'] = True
+        # check if interface is member if a bridge
+        geneve['is_bridge_member'] = is_bridge_member(conf, geneve['intf'])
         return geneve
 
     # set new configuration level
@@ -93,13 +96,11 @@ def get_config():
 
 def verify(geneve):
     if geneve['deleted']:
-        interface = geneve['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if geneve['is_bridge_member']:
+            interface = geneve['intf']
+            bridge = geneve['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     if not geneve['remote']:
diff --git a/src/conf_mode/interfaces-l2tpv3.py b/src/conf_mode/interfaces-l2tpv3.py
index 11ba9acdd..c7c9f6aca 100755
--- a/src/conf_mode/interfaces-l2tpv3.py
+++ b/src/conf_mode/interfaces-l2tpv3.py
@@ -18,13 +18,13 @@ import os
 
 from sys import exit
 from copy import deepcopy
+from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.ifconfig import L2TPv3If, Interface
 from vyos import ConfigError
 from vyos.util import call
-from vyos.util import is_bridge_member
-from netifaces import interfaces
+from vyos.validate import is_bridge_member
 
 default_config_data = {
     'address': [],
@@ -39,6 +39,7 @@ default_config_data = {
     'ipv6_eui64_prefix': '',
     'ipv6_forwarding': 1,
     'ipv6_dup_addr_detect': 1,
+    'is_bridge_member': False
     'mtu': 1488,
     'peer_session_id': '',
     'peer_tunnel_id': '',
@@ -68,15 +69,16 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists('interfaces l2tpv3 ' + l2tpv3['intf']):
         l2tpv3['deleted'] = True
-        # to delete the l2tpv3 interface we need to current
-        # tunnel_id and session_id
-        if conf.exists_effective('interfaces l2tpv3 {} tunnel-id'.format(l2tpv3['intf'])):
-            l2tpv3['tunnel_id'] = conf.return_effective_value(
-                'interfaces l2tpv3 {} tunnel-id'.format(l2tpv3['intf']))
+        interface = l2tpv3['intf']
+        # check if interface is member if a bridge
+        l2tpv3['is_bridge_member'] = is_bridge_member(conf, interface)
 
-        if conf.exists_effective('interfaces l2tpv3 {} session-id'.format(l2tpv3['intf'])):
-            l2tpv3['session_id'] = conf.return_effective_value(
-                'interfaces l2tpv3 {} session-id'.format(l2tpv3['intf']))
+        # to delete the l2tpv3 interface we need the current tunnel_id and session_id
+        if conf.exists_effective(f'interfaces l2tpv3 {interface} tunnel-id'):
+            l2tpv3['tunnel_id'] = conf.return_effective_value(f'interfaces l2tpv3 {interface} tunnel-id')
+
+        if conf.exists_effective(f'interfaces l2tpv3 {interface} session-id'):
+            l2tpv3['session_id'] = conf.return_effective_value(f'interfaces l2tpv3 {interface} session-id')
 
         return l2tpv3
 
@@ -158,12 +160,11 @@ def verify(l2tpv3):
     interface = l2tpv3['intf']
 
     if l2tpv3['deleted']:
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if l2tpv3['is_bridge_member']:
+            interface = l2tpv3['intf']
+            bridge = l2tpv3['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     if not l2tpv3['local_address']:
diff --git a/src/conf_mode/interfaces-openvpn.py b/src/conf_mode/interfaces-openvpn.py
index 836deb64b..9cea07a61 100755
--- a/src/conf_mode/interfaces-openvpn.py
+++ b/src/conf_mode/interfaces-openvpn.py
@@ -26,11 +26,10 @@ from shutil import rmtree
 
 from vyos.config import Config
 from vyos.ifconfig import VTunIf
-from vyos.util import call, is_bridge_member, chown, chmod_600, chmod_755
-from vyos.validate import is_addr_assigned
-from vyos import ConfigError
 from vyos.template import render
-
+from vyos.util import call, chown, chmod_600, chmod_755
+from vyos.validate import is_addr_assigned, is_bridge_member
+from vyos import ConfigError
 
 user = 'openvpn'
 group = 'openvpn'
@@ -55,6 +54,7 @@ default_config_data = {
     'ipv6_dup_addr_detect': 1,
     'ipv6_local_address': [],
     'ipv6_remote_address': [],
+    'is_bridge_member': False,
     'ping_restart': '60',
     'ping_interval': '10',
     'local_address': [],
@@ -197,6 +197,8 @@ def get_config():
     # Check if interface instance has been removed
     if not conf.exists('interfaces openvpn ' + openvpn['intf']):
         openvpn['deleted'] = True
+        # check if interface is member if a bridge
+        openvpn['is_bridge_member'] = is_bridge_member(conf, openvpn['intf'])
         return openvpn
 
     # Check if we belong to any bridge interface
@@ -598,13 +600,11 @@ def get_config():
 
 def verify(openvpn):
     if openvpn['deleted']:
-        interface = openvpn['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if openvpn['is_bridge_member']:
+            interface = openvpn['intf']
+            bridge = openvpn['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
 
diff --git a/src/conf_mode/interfaces-pseudo-ethernet.py b/src/conf_mode/interfaces-pseudo-ethernet.py
index 655006146..3e5b7be5b 100755
--- a/src/conf_mode/interfaces-pseudo-ethernet.py
+++ b/src/conf_mode/interfaces-pseudo-ethernet.py
@@ -20,11 +20,11 @@ from copy import deepcopy
 from sys import exit
 from netifaces import interfaces
 
+from vyos.config import Config
+from vyos.configdict import list_diff, vlan_to_dict
 from vyos.ifconfig import MACVLANIf
 from vyos.ifconfig_vlan import apply_vlan_config, verify_vlan_config
-from vyos.configdict import list_diff, vlan_to_dict
-from vyos.config import Config
-from vyos.util import is_bridge_member
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 default_config_data = {
@@ -39,6 +39,7 @@ default_config_data = {
     'dhcpv6_temporary': False,
     'disable': False,
     'disable_link_detect': 1,
+    'intf': '',
     'ip_arp_cache_tmo': 30,
     'ip_disable_arp_filter': 1,
     'ip_enable_arp_accept': 0,
@@ -50,7 +51,7 @@ default_config_data = {
     'ipv6_eui64_prefix': '',
     'ipv6_forwarding': 1,
     'ipv6_dup_addr_detect': 1,
-    'intf': '',
+    'is_bridge_member': False,
     'source_interface': '',
     'source_interface_changed': False,
     'mac': '',
@@ -76,6 +77,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists(cfg_base):
         peth['deleted'] = True
+        # check if interface is member if a bridge
+        peth['is_bridge_member'] = is_bridge_member(conf, peth['intf'])
         return peth
 
     # set new configuration level
@@ -218,13 +221,11 @@ def get_config():
 
 def verify(peth):
     if peth['deleted']:
-        interface = peth['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if peth['is_bridge_member']::
+            interface = peth['intf']
+            bridge = peth['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     if not peth['source_interface']:
diff --git a/src/conf_mode/interfaces-vxlan.py b/src/conf_mode/interfaces-vxlan.py
index 6639a9b0d..d238ddb57 100755
--- a/src/conf_mode/interfaces-vxlan.py
+++ b/src/conf_mode/interfaces-vxlan.py
@@ -22,7 +22,7 @@ from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.ifconfig import VXLANIf, Interface
-from vyos.util import is_bridge_member
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 default_config_data = {
@@ -42,6 +42,7 @@ default_config_data = {
     'ipv6_eui64_prefix': '',
     'ipv6_forwarding': 1,
     'ipv6_dup_addr_detect': 1,
+    'is_bridge_member': False,
     'source_address': '',
     'source_interface': '',
     'mtu': 1450,
@@ -64,6 +65,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists('interfaces vxlan ' + vxlan['intf']):
         vxlan['deleted'] = True
+        # check if interface is member if a bridge
+        vxlan['is_bridge_member'] = is_bridge_member(conf, vxlan['intf'])
         return vxlan
 
     # set new configuration level
@@ -154,13 +157,11 @@ def get_config():
 
 def verify(vxlan):
     if vxlan['deleted']:
-        interface = vxlan['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if vxlan['is_bridge_member']:
+            interface = vxlan['intf']
+            bridge = vxlan['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     if vxlan['mtu'] < 1500:
@@ -250,7 +251,7 @@ def apply(vxlan):
         for addr in vxlan['address']:
             v.add_addr(addr)
 
-        # As the bond interface is always disabled first when changing
+        # As the VXLAN interface is always disabled first when changing
         # parameters we will only re-enable the interface if it is not
         # administratively disabled
         if not vxlan['disable']:
diff --git a/src/conf_mode/interfaces-wireguard.py b/src/conf_mode/interfaces-wireguard.py
index 8bf81c747..423700370 100755
--- a/src/conf_mode/interfaces-wireguard.py
+++ b/src/conf_mode/interfaces-wireguard.py
@@ -24,8 +24,8 @@ from netifaces import interfaces
 from vyos.config import Config
 from vyos.configdict import list_diff
 from vyos.ifconfig import WireGuardIf
-from vyos.util import chown, is_bridge_member, chmod_750
-from vyos.util import call
+from vyos.util import chown, chmod_750, call
+from vyos.validate import is_bridge_member
 from vyos import ConfigError
 
 kdir = r'/config/auth/wireguard'
@@ -38,6 +38,7 @@ default_config_data = {
     'lport': None,
     'deleted': False,
     'disable': False,
+    'is_bridge_member': False,
     'fwmark': 0x00,
     'mtu': 1420,
     'peer': [],
@@ -80,6 +81,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists(base + [wg['intf']]):
         wg['deleted'] = True
+        # check if interface is member if a bridge
+        wg['is_bridge_member'] = is_bridge_member(conf, wg['intf'])
         return wg
 
     conf.set_level(base + [wg['intf']])
@@ -189,12 +192,11 @@ def verify(wg):
     interface = wg['intf']
 
     if wg['deleted']:
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if wg['is_bridge_member']:
+            interface = wg['intf']
+            bridge = wg['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     vrf_name = wg['vrf']
diff --git a/src/conf_mode/interfaces-wireless.py b/src/conf_mode/interfaces-wireless.py
index 1964af6e1..42842f9bd 100755
--- a/src/conf_mode/interfaces-wireless.py
+++ b/src/conf_mode/interfaces-wireless.py
@@ -27,10 +27,10 @@ from vyos.config import Config
 from vyos.configdict import list_diff, vlan_to_dict
 from vyos.ifconfig import WiFiIf
 from vyos.ifconfig_vlan import apply_vlan_config, verify_vlan_config
-from vyos.util import chown, is_bridge_member, call
-from vyos import ConfigError
 from vyos.template import render
-
+from vyos.util import chown, call
+from vyos.validate import is_bridge_member
+from vyos import ConfigError
 
 default_config_data = {
     'address': [],
@@ -91,6 +91,7 @@ default_config_data = {
     'ipv6_eui64_prefix': '',
     'ipv6_forwarding': 1,
     'ipv6_dup_addr_detect': 1,
+    'is_bridge_member': False,
     'mac' : '',
     'max_stations' : '',
     'mgmt_frame_protection' : 'disabled',
@@ -136,6 +137,8 @@ def get_config():
     cfg_base = 'interfaces wireless ' + wifi['intf']
     if not conf.exists(cfg_base):
         wifi['deleted'] = True
+        # check if interface is member if a bridge
+        wifi['is_bridge_member'] = is_bridge_member(conf, wifi['intf'])
         # we can not bail out early as wireless interface can not be removed
         # Kernel will complain with: RTNETLINK answers: Operation not supported.
         # Thus we need to remove individual settings
@@ -528,15 +531,12 @@ def get_config():
 
 def verify(wifi):
     if wifi['deleted']:
-        interface = wifi['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
-        return None
+        if wifi['is_bridge_member']:
+            interface = wifi['intf']
+            bridge = wifi['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
 
+        return None
 
     if wifi['op_mode'] != 'monitor' and not wifi['ssid']:
         raise ConfigError('SSID must be set for {}'.format(wifi['intf']))
diff --git a/src/conf_mode/interfaces-wirelessmodem.py b/src/conf_mode/interfaces-wirelessmodem.py
index da1855cd9..40bd1bbaf 100755
--- a/src/conf_mode/interfaces-wirelessmodem.py
+++ b/src/conf_mode/interfaces-wirelessmodem.py
@@ -21,14 +21,10 @@ from copy import deepcopy
 from netifaces import interfaces
 
 from vyos.config import Config
-from vyos.util import chown
-from vyos.util import chmod_755
-from vyos.util import is_bridge_member
-from vyos.util import cmd
-from vyos.util import call
-from vyos import ConfigError
 from vyos.template import render
-
+from vyos.util import chown, chmod_755, cmd, call
+from vyos.validate import is_bridge_member
+from vyos import ConfigError
 
 default_config_data = {
     'address': [],
@@ -44,6 +40,7 @@ default_config_data = {
     'metric': '10',
     'mtu': '1500',
     'name_server': True,
+    'is_bridge_member': False,
     'intf': '',
     'vrf': ''
 }
@@ -70,6 +67,8 @@ def get_config():
     # Check if interface has been removed
     if not conf.exists('interfaces wirelessmodem ' + wwan['intf']):
         wwan['deleted'] = True
+        # check if interface is member if a bridge
+        wwan['is_bridge_member'] = is_bridge_member(conf, wwan['intf'])
         return wwan
 
     # set new configuration level
@@ -119,13 +118,11 @@ def get_config():
 
 def verify(wwan):
     if wwan['deleted']:
-        interface = wwan['intf']
-        is_member, bridge = is_bridge_member(interface)
-        if is_member:
-            # can not use a f'' formatted-string here as bridge would not get
-            # expanded in the print statement
-            raise ConfigError('Can not delete interface "{0}" as it ' \
-                              'is a member of bridge "{1}"!'.format(interface, bridge))
+        if wwan['is_bridge_member']::
+            interface = wwan['intf']
+            bridge = wwan['is_bridge_member']
+            raise ConfigError(f'Interface "{interface}" can not be deleted as it belongs to bridge "{bridge}"!')
+
         return None
 
     if not wwan['apn']: