T6199: replace netifaces.interfaces() with common custom helpers

* Use interface_exists() outside of verify()
* Use verify_interface_exists() in verify() to drop common error message

(cherry picked from commit 4c7c168fe970b807750a05ceb66b70c0d8652535)

18 files changed, 54 insertions, 75 deletions

diff --git a/src/conf_mode/interfaces_bonding.py b/src/conf_mode/interfaces_bonding.py
index 8184d8415..d19de20c5 100755
--- a/src/conf_mode/interfaces_bonding.py
+++ b/src/conf_mode/interfaces_bonding.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2023 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -17,7 +17,7 @@
 import os
 
 from sys import exit
-from netifaces import interfaces
+
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdict import is_node_changed
@@ -29,7 +29,6 @@ from vyos.configverify import verify_bridge_delete
 from vyos.configverify import verify_dhcpv6
 from vyos.configverify import verify_mirror_redirect
 from vyos.configverify import verify_mtu_ipv6
-from vyos.configverify import verify_source_interface
 from vyos.configverify import verify_vlan_config
 from vyos.configverify import verify_vrf
 from vyos.ifconfig import BondIf
@@ -38,6 +37,7 @@ from vyos.ifconfig import Section
 from vyos.template import render_to_string
 from vyos.utils.dict import dict_search
 from vyos.utils.dict import dict_to_paths_values
+from vyos.utils.network import interface_exists
 from vyos.configdict import has_address_configured
 from vyos.configdict import has_vrf_configured
 from vyos.configdep import set_dependents, call_dependents
@@ -209,7 +209,7 @@ def verify(bond):
             if interface == 'lo':
                 raise ConfigError('Loopback interface "lo" can not be added to a bond')
 
-            if interface not in interfaces():
+            if not interface_exists(interface):
                 raise ConfigError(error_msg + 'it does not exist!')
 
             if 'is_bridge_member' in interface_config:
diff --git a/src/conf_mode/interfaces_geneve.py b/src/conf_mode/interfaces_geneve.py
index f6694ddde..769139e0f 100755
--- a/src/conf_mode/interfaces_geneve.py
+++ b/src/conf_mode/interfaces_geneve.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2022 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -15,7 +15,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from sys import exit
-from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
@@ -26,6 +25,7 @@ from vyos.configverify import verify_bridge_delete
 from vyos.configverify import verify_mirror_redirect
 from vyos.configverify import verify_bond_bridge_member
 from vyos.ifconfig import GeneveIf
+from vyos.utils.network import interface_exists
 from vyos import ConfigError
 
 from vyos import airbag
@@ -77,8 +77,8 @@ def generate(geneve):
 def apply(geneve):
     # Check if GENEVE interface already exists
     if 'rebuild_required' in geneve or 'delete' in geneve:
-        if geneve['ifname'] in interfaces():
-            g = GeneveIf(geneve['ifname'])
+        if interface_exists(geneve['ifname']):
+            g = GeneveIf(**geneve)
             # GENEVE is super picky and the tunnel always needs to be recreated,
             # thus we can simply always delete it first.
             g.remove()
diff --git a/src/conf_mode/interfaces_l2tpv3.py b/src/conf_mode/interfaces_l2tpv3.py
index e1db3206e..e25793543 100755
--- a/src/conf_mode/interfaces_l2tpv3.py
+++ b/src/conf_mode/interfaces_l2tpv3.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2020 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -14,10 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import os
-
 from sys import exit
-from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
@@ -30,6 +27,7 @@ from vyos.configverify import verify_bond_bridge_member
 from vyos.ifconfig import L2TPv3If
 from vyos.utils.kernel import check_kmod
 from vyos.utils.network import is_addr_assigned
+from vyos.utils.network import interface_exists
 from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
@@ -87,7 +85,7 @@ def generate(l2tpv3):
 
 def apply(l2tpv3):
     # Check if L2TPv3 interface already exists
-    if l2tpv3['ifname'] in interfaces():
+    if interface_exists(l2tpv3['ifname']):
         # L2TPv3 is picky when changing tunnels/sessions, thus we can simply
         # always delete it first.
         l = L2TPv3If(**l2tpv3)
diff --git a/src/conf_mode/interfaces_macsec.py b/src/conf_mode/interfaces_macsec.py
index 0a927ac88..eb0ca9a8b 100755
--- a/src/conf_mode/interfaces_macsec.py
+++ b/src/conf_mode/interfaces_macsec.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2020-2023 VyOS maintainers and contributors
+# Copyright (C) 2020-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -16,7 +16,6 @@
 
 import os
 
-from netifaces import interfaces
 from sys import exit
 
 from vyos.config import Config
@@ -35,6 +34,7 @@ from vyos.ifconfig import Interface
 from vyos.template import render
 from vyos.utils.process import call
 from vyos.utils.dict import dict_search
+from vyos.utils.network import interface_exists
 from vyos.utils.process import is_systemd_service_running
 from vyos import ConfigError
 from vyos import airbag
@@ -172,8 +172,8 @@ def apply(macsec):
     if 'deleted' in macsec or 'shutdown_required' in macsec:
         call(f'systemctl stop {systemd_service}')
 
-        if macsec['ifname'] in interfaces():
-            tmp = MACsecIf(macsec['ifname'])
+        if interface_exists(macsec['ifname']):
+            tmp = MACsecIf(**macsec)
             tmp.remove()
 
         if 'deleted' in macsec:
diff --git a/src/conf_mode/interfaces_openvpn.py b/src/conf_mode/interfaces_openvpn.py
index 45569dd21..402543a33 100755
--- a/src/conf_mode/interfaces_openvpn.py
+++ b/src/conf_mode/interfaces_openvpn.py
@@ -26,7 +26,6 @@ from ipaddress import IPv4Network
 from ipaddress import IPv6Address
 from ipaddress import IPv6Network
 from ipaddress import summarize_address_range
-from netifaces import interfaces
 from secrets import SystemRandom
 from shutil import rmtree
 
@@ -63,6 +62,7 @@ from vyos.utils.process import call
 from vyos.utils.permission import chown
 from vyos.utils.process import cmd
 from vyos.utils.network import is_addr_assigned
+from vyos.utils.network import interface_exists
 
 from vyos import ConfigError
 from vyos import airbag
@@ -683,7 +683,7 @@ def apply(openvpn):
             if os.path.isfile(cleanup_file):
                 os.unlink(cleanup_file)
 
-        if interface in interfaces():
+        if interface_exists(interface):
             VTunIf(interface).remove()
 
     # dynamically load/unload DCO Kernel extension if requested
diff --git a/src/conf_mode/interfaces_pppoe.py b/src/conf_mode/interfaces_pppoe.py
index 42f084309..f315493cd 100755
--- a/src/conf_mode/interfaces_pppoe.py
+++ b/src/conf_mode/interfaces_pppoe.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2021 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -18,7 +18,6 @@ import os
 
 from sys import exit
 from copy import deepcopy
-from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
@@ -26,7 +25,6 @@ from vyos.configdict import is_node_changed
 from vyos.configdict import get_pppoe_interfaces
 from vyos.configverify import verify_authentication
 from vyos.configverify import verify_source_interface
-from vyos.configverify import verify_interface_exists
 from vyos.configverify import verify_vrf
 from vyos.configverify import verify_mtu_ipv6
 from vyos.configverify import verify_mirror_redirect
diff --git a/src/conf_mode/interfaces_pseudo-ethernet.py b/src/conf_mode/interfaces_pseudo-ethernet.py
index dce5c2358..446beffd3 100755
--- a/src/conf_mode/interfaces_pseudo-ethernet.py
+++ b/src/conf_mode/interfaces_pseudo-ethernet.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2022 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -15,7 +15,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from sys import exit
-from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
@@ -29,8 +28,8 @@ from vyos.configverify import verify_source_interface
 from vyos.configverify import verify_vlan_config
 from vyos.configverify import verify_mtu_parent
 from vyos.configverify import verify_mirror_redirect
-from vyos.configverify import verify_bond_bridge_member
 from vyos.ifconfig import MACVLANIf
+from vyos.utils.network import interface_exists
 from vyos import ConfigError
 
 from vyos import airbag
@@ -84,8 +83,8 @@ def generate(peth):
 def apply(peth):
     # Check if the MACVLAN interface already exists
     if 'rebuild_required' in peth or 'deleted' in peth:
-        if peth['ifname'] in interfaces():
-            p = MACVLANIf(peth['ifname'])
+        if interface_exists(peth['ifname']):
+            p = MACVLANIf(**peth)
             # MACVLAN is always needs to be recreated,
             # thus we can simply always delete it first.
             p.remove()
diff --git a/src/conf_mode/interfaces_tunnel.py b/src/conf_mode/interfaces_tunnel.py
index efa5ebc64..43ba72857 100755
--- a/src/conf_mode/interfaces_tunnel.py
+++ b/src/conf_mode/interfaces_tunnel.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2018-2022 yOS maintainers and contributors
+# Copyright (C) 2018-2024 yOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -14,10 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import os
-
 from sys import exit
-from netifaces import interfaces
 
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
@@ -31,10 +28,10 @@ from vyos.configverify import verify_vrf
 from vyos.configverify import verify_tunnel
 from vyos.configverify import verify_bond_bridge_member
 from vyos.ifconfig import Interface
-from vyos.ifconfig import Section
 from vyos.ifconfig import TunnelIf
-from vyos.utils.network import get_interface_config
 from vyos.utils.dict import dict_search
+from vyos.utils.network import get_interface_config
+from vyos.utils.network import interface_exists
 from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
@@ -202,7 +199,7 @@ def apply(tunnel):
     if ('deleted' in tunnel or 'encapsulation_changed' in tunnel or encap in
         ['gretap', 'ip6gretap', 'erspan', 'ip6erspan'] or remote in ['any'] or
         'key_changed' in tunnel):
-        if interface in interfaces():
+        if interface_exists(interface):
             tmp = Interface(interface)
             tmp.remove()
         if 'deleted' in tunnel:
diff --git a/src/conf_mode/interfaces_virtual-ethernet.py b/src/conf_mode/interfaces_virtual-ethernet.py
index 8efe89c41..cb6104f59 100755
--- a/src/conf_mode/interfaces_virtual-ethernet.py
+++ b/src/conf_mode/interfaces_virtual-ethernet.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2022 VyOS maintainers and contributors
+# Copyright (C) 2022-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -16,7 +16,6 @@
 
 from sys import exit
 
-from netifaces import interfaces
 from vyos import ConfigError
 from vyos import airbag
 from vyos.config import Config
@@ -25,7 +24,7 @@ from vyos.configverify import verify_address
 from vyos.configverify import verify_bridge_delete
 from vyos.configverify import verify_vrf
 from vyos.ifconfig import VethIf
-
+from vyos.utils.network import interface_exists
 airbag.enable()
 
 def get_config(config=None):
@@ -92,8 +91,8 @@ def generate(peth):
 def apply(veth):
     # Check if the Veth interface already exists
     if 'rebuild_required' in veth or 'deleted' in veth:
-        if veth['ifname'] in interfaces():
-            p = VethIf(veth['ifname'])
+        if interface_exists(veth['ifname']):
+            p = VethIf(**veth)
             p.remove()
 
     if 'deleted' not in veth:
diff --git a/src/conf_mode/interfaces_vti.py b/src/conf_mode/interfaces_vti.py
index 9871810ae..06a65a390 100755
--- a/src/conf_mode/interfaces_vti.py
+++ b/src/conf_mode/interfaces_vti.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2021 VyOS maintainers and contributors
+# Copyright (C) 2021-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -14,7 +14,6 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from netifaces import interfaces
 from sys import exit
 
 from vyos.config import Config
diff --git a/src/conf_mode/interfaces_vxlan.py b/src/conf_mode/interfaces_vxlan.py
index 4251e611b..bf0a30a00 100755
--- a/src/conf_mode/interfaces_vxlan.py
+++ b/src/conf_mode/interfaces_vxlan.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2023 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -17,7 +17,6 @@
 import os
 
 from sys import exit
-from netifaces import interfaces
 
 from vyos.base import Warning
 from vyos.config import Config
@@ -35,6 +34,7 @@ from vyos.ifconfig import Interface
 from vyos.ifconfig import VXLANIf
 from vyos.template import is_ipv6
 from vyos.utils.dict import dict_search
+from vyos.utils.network import interface_exists
 from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
@@ -212,8 +212,8 @@ def generate(vxlan):
 def apply(vxlan):
     # Check if the VXLAN interface already exists
     if 'rebuild_required' in vxlan or 'delete' in vxlan:
-        if vxlan['ifname'] in interfaces():
-            v = VXLANIf(vxlan['ifname'])
+        if interface_exists(vxlan['ifname']):
+            v = VXLANIf(**vxlan)
             # VXLAN is super picky and the tunnel always needs to be recreated,
             # thus we can simply always delete it first.
             v.remove()
diff --git a/src/conf_mode/policy_local-route.py b/src/conf_mode/policy_local-route.py
index 91e4fce2c..d19b23e18 100755
--- a/src/conf_mode/policy_local-route.py
+++ b/src/conf_mode/policy_local-route.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2020-2023 VyOS maintainers and contributors
+# Copyright (C) 2020-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -19,12 +19,12 @@ import os
 from itertools import product
 from sys import exit
 
-from netifaces import interfaces
 from vyos.config import Config
 from vyos.configdict import dict_merge
 from vyos.configdict import node_changed
 from vyos.configdict import leaf_node_changed
 from vyos.template import render
+from vyos.configverify import verify_interface_exists
 from vyos.utils.process import call
 from vyos import ConfigError
 from vyos import airbag
@@ -227,8 +227,7 @@ def verify(pbr):
 
                 if 'inbound_interface' in pbr_route['rule'][rule]:
                     interface = pbr_route['rule'][rule]['inbound_interface']
-                    if interface not in interfaces():
-                        raise ConfigError(f'Interface "{interface}" does not exist')
+                    verify_interface_exists(interface)
 
     return None
 
diff --git a/src/conf_mode/protocols_igmp-proxy.py b/src/conf_mode/protocols_igmp-proxy.py
index 40db417dd..afcef0985 100755
--- a/src/conf_mode/protocols_igmp-proxy.py
+++ b/src/conf_mode/protocols_igmp-proxy.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2018-2020 VyOS maintainers and contributors
+# Copyright (C) 2018-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -17,10 +17,10 @@
 import os
 
 from sys import exit
-from netifaces import interfaces
 
 from vyos.base import Warning
 from vyos.config import Config
+from vyos.configverify import verify_interface_exists
 from vyos.template import render
 from vyos.utils.process import call
 from vyos.utils.dict import dict_search
@@ -65,8 +65,7 @@ def verify(igmp_proxy):
 
     upstream = 0
     for interface, config in igmp_proxy['interface'].items():
-        if interface not in interfaces():
-            raise ConfigError(f'Interface "{interface}" does not exist')
+        verify_interface_exists(interface)
         if dict_search('role', config) == 'upstream':
             upstream += 1
 
diff --git a/src/conf_mode/qos.py b/src/conf_mode/qos.py
index 2b4fcc1bf..818f9a7ac 100755
--- a/src/conf_mode/qos.py
+++ b/src/conf_mode/qos.py
@@ -23,6 +23,7 @@ from vyos.base import Warning
 from vyos.config import Config
 from vyos.configdep import set_dependents, call_dependents
 from vyos.configdict import dict_merge
+from vyos.configverify import verify_interface_exists
 from vyos.ifconfig import Section
 from vyos.qos import CAKE
 from vyos.qos import DropTail
@@ -37,7 +38,6 @@ from vyos.qos import RoundRobin
 from vyos.qos import TrafficShaper
 from vyos.qos import TrafficShaperHFSC
 from vyos.utils.dict import dict_search_recursive
-from vyos.utils.network import interface_exists
 from vyos.utils.process import run
 from vyos import ConfigError
 from vyos import airbag
@@ -215,11 +215,10 @@ def apply(qos):
         return None
 
     for interface, interface_config in qos['interface'].items():
-        if not interface_exists(interface):
+        if not verify_interface_exists(interface, warning_only=True):
             # When shaper is bound to a dialup (e.g. PPPoE) interface it is
             # possible that it is yet not availbale when to QoS code runs.
-            # Skip the configuration and inform the user
-            Warning(f'Interface "{interface}" does not exist!')
+            # Skip the configuration and inform the user via warning_only=True
             continue
 
         for direction in ['egress', 'ingress']:
diff --git a/src/conf_mode/service_mdns_repeater.py b/src/conf_mode/service_mdns_repeater.py
index 6526c23d1..207da5e03 100755
--- a/src/conf_mode/service_mdns_repeater.py
+++ b/src/conf_mode/service_mdns_repeater.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2017-2022 VyOS maintainers and contributors
+# Copyright (C) 2017-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -18,9 +18,10 @@ import os
 
 from json import loads
 from sys import exit
-from netifaces import ifaddresses, interfaces, AF_INET, AF_INET6
+from netifaces import ifaddresses, AF_INET, AF_INET6
 
 from vyos.config import Config
+from vyos.configverify import verify_interface_exists
 from vyos.ifconfig.vrrp import VRRP
 from vyos.template import render
 from vyos.utils.process import call
@@ -64,8 +65,7 @@ def verify(mdns):
     # For mdns-repeater to work it is essential that the interfaces has
     # an IPv4 address assigned
     for interface in mdns['interface']:
-        if interface not in interfaces():
-            raise ConfigError(f'Interface "{interface}" does not exist!')
+        verify_interface_exists(interface)
 
         if mdns['ip_version'] in ['ipv4', 'both'] and AF_INET not in ifaddresses(interface):
             raise ConfigError('mDNS repeater requires an IPv4 address to be '
diff --git a/src/conf_mode/system_flow-accounting.py b/src/conf_mode/system_flow-accounting.py
index 206f513c8..2dacd92da 100755
--- a/src/conf_mode/system_flow-accounting.py
+++ b/src/conf_mode/system_flow-accounting.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2018-2023 VyOS maintainers and contributors
+# Copyright (C) 2018-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -20,11 +20,10 @@ import re
 from sys import exit
 from ipaddress import ip_address
 
-from vyos.base import Warning
 from vyos.config import Config
 from vyos.config import config_dict_merge
 from vyos.configverify import verify_vrf
-from vyos.ifconfig import Section
+from vyos.configverify import verify_interface_exists
 from vyos.template import render
 from vyos.utils.process import call
 from vyos.utils.process import cmd
@@ -184,10 +183,7 @@ def verify(flow_config):
 
     # check that all configured interfaces exists in the system
     for interface in flow_config['interface']:
-        if interface not in Section.interfaces():
-            # Changed from error to warning to allow adding dynamic interfaces
-            # and interface templates
-            Warning(f'Interface "{interface}" is not presented in the system')
+        verify_interface_exists(interface, warning_only=True)
 
     # check sFlow configuration
     if 'sflow' in flow_config:
diff --git a/src/conf_mode/system_option.py b/src/conf_mode/system_option.py
index 7ed451e16..a2e5db575 100755
--- a/src/conf_mode/system_option.py
+++ b/src/conf_mode/system_option.py
@@ -16,12 +16,12 @@
 
 import os
 
-from netifaces import interfaces
 from sys import exit
 from time import sleep
 
 from vyos.config import Config
 from vyos.configverify import verify_source_interface
+from vyos.configverify import verify_interface_exists
 from vyos.system import grub_util
 from vyos.template import render
 from vyos.utils.process import cmd
@@ -56,9 +56,7 @@ def verify(options):
     if 'http_client' in options:
         config = options['http_client']
         if 'source_interface' in config:
-            if not config['source_interface'] in interfaces():
-                raise ConfigError(f'Source interface {source_interface} does not '
-                                  f'exist'.format(**config))
+            verify_interface_exists(config['source_interface'])
 
         if {'source_address', 'source_interface'} <= set(config):
             raise ConfigError('Can not define both HTTP source-interface and source-address')
diff --git a/src/conf_mode/vpn_ipsec.py b/src/conf_mode/vpn_ipsec.py
index 0c2f232df..d07aca979 100755
--- a/src/conf_mode/vpn_ipsec.py
+++ b/src/conf_mode/vpn_ipsec.py
@@ -168,9 +168,7 @@ def verify(ipsec):
         for interface in ipsec['interface']:
             # exclude check interface for dynamic interfaces
             if tmp.match(interface):
-                if not interface_exists(interface):
-                    Warning(f'Interface "{interface}" does not exist yet and cannot be used '
-                            f'for IPsec until it is up!')
+                verify_interface_exists(interface, warning_only=True)
             else:
                 verify_interface_exists(interface)