T4630: can not use same source-interface for macsec and pseudo-ethernet

A macsec interface requires a dedicated source interface, it can not be
shared with another macsec or a pseudo-ethernet interface.

set interfaces macsec macsec10 address '192.168.2.1/30'
set interfaces macsec macsec10 security cipher 'gcm-aes-256'
set interfaces macsec macsec10 security encrypt
set interfaces macsec macsec10 security mka cak '232e44b7fda6f8e2d88a07bf78a7aff4232e44b7fda6f8e2d88a07bf78a7aff4'
set interfaces macsec macsec10 security mka ckn '09924585a6f3010208cf5222ef24c821405b0e34f4b4f63b1f0ced474b9bb6e6'
set interfaces macsec macsec10 source-interface 'eth1'
commit

set interfaces pseudo-ethernet peth0 source-interface eth1
commit

Reuslts in

FileNotFoundError: [Errno 2] failed to run command: ip link add peth0 link eth1 type macvlan mode private
returned:
exit code: 2

noteworthy:
cmd 'ip link add peth0 link eth1 type macvlan mode private'
returned (out):

returned (err):
RTNETLINK answers: Device or resource busy

[[interfaces pseudo-ethernet peth0]] failed
Commit failed

4 files changed, 22 insertions, 10 deletions

diff --git a/python/vyos/configdict.py b/python/vyos/configdict.py
index 8f822a97d..912bc94f2 100644
--- a/python/vyos/configdict.py
+++ b/python/vyos/configdict.py
@@ -295,11 +295,18 @@ def is_source_interface(conf, interface, intftype=None):
     """
     ret_val = None
     intftypes = ['macsec', 'pppoe', 'pseudo-ethernet', 'tunnel', 'vxlan']
-    if intftype not in intftypes + [None]:
+    if not intftype:
+        intftype = intftypes
+
+    if isinstance(intftype, str):
+        intftype = [intftype]
+    elif not isinstance(intftype, list):
+        raise ValueError(f'Interface type "{type(intftype)}" must be either str or list!')
+
+    if not all(x in intftypes for x in intftype):
         raise ValueError(f'unknown interface type "{intftype}" or it can not '
             'have a source-interface')
 
-    intftype = intftypes if intftype == None else [intftype]
     for it in intftype:
         base = ['interfaces', it]
         for intf in conf.list_nodes(base):
diff --git a/python/vyos/configverify.py b/python/vyos/configverify.py
index 2ab3cb408..447ec795c 100644
--- a/python/vyos/configverify.py
+++ b/python/vyos/configverify.py
@@ -295,6 +295,12 @@ def verify_source_interface(config):
         raise ConfigError(f'Invalid source-interface "{src_ifname}". Interface '
                           f'is already a member of bond "{bond_name}"!')
 
+    if 'is_source_interface' in config:
+        tmp = config['is_source_interface']
+        src_ifname = config['source_interface']
+        raise ConfigError(f'Can not use source-interface "{src_ifname}", it already ' \
+                          f'belongs to interface "{tmp}"!')
+
 def verify_dhcpv6(config):
     """
     Common helper function used by interface implementations to perform
diff --git a/src/conf_mode/interfaces-macsec.py b/src/conf_mode/interfaces-macsec.py
index 870049a88..649ea8d50 100755
--- a/src/conf_mode/interfaces-macsec.py
+++ b/src/conf_mode/interfaces-macsec.py
@@ -67,7 +67,7 @@ def get_config(config=None):
         macsec.update({'shutdown_required': {}})
 
     if 'source_interface' in macsec:
-        tmp = is_source_interface(conf, macsec['source_interface'], 'macsec')
+        tmp = is_source_interface(conf, macsec['source_interface'], ['macsec', 'pseudo-ethernet'])
         if tmp and tmp != ifname: macsec.update({'is_source_interface' : tmp})
 
     return macsec
@@ -102,12 +102,6 @@ def verify(macsec):
             # gcm-aes-128 requires a 128bit long key - 64 characters (string) = 32byte = 256bit
             raise ConfigError('gcm-aes-128 requires a 256bit long key!')
 
-    if 'is_source_interface' in macsec:
-        tmp = macsec['is_source_interface']
-        src_ifname = macsec['source_interface']
-        raise ConfigError(f'Can not use source-interface "{src_ifname}", it already ' \
-                          f'belongs to interface "{tmp}"!')
-
     if 'source_interface' in macsec:
         # MACsec adds a 40 byte overhead (32 byte MACsec + 8 bytes VLAN 802.1ad
         # and 802.1q) - we need to check the underlaying MTU if our configured
diff --git a/src/conf_mode/interfaces-pseudo-ethernet.py b/src/conf_mode/interfaces-pseudo-ethernet.py
index f26a50a0e..20f2b1975 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) 2019-2020 VyOS maintainers and contributors
+# Copyright (C) 2019-2022 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
@@ -19,6 +19,7 @@ from sys import exit
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdict import is_node_changed
+from vyos.configdict import is_source_interface
 from vyos.configverify import verify_vrf
 from vyos.configverify import verify_address
 from vyos.configverify import verify_bridge_delete
@@ -51,6 +52,10 @@ def get_config(config=None):
     if 'source_interface' in peth:
         _, peth['parent'] = get_interface_dict(conf, ['interfaces', 'ethernet'],
                                                peth['source_interface'])
+        # test if source-interface is maybe already used by another interface
+        tmp = is_source_interface(conf, peth['source_interface'], ['macsec'])
+        if tmp and tmp != ifname: peth.update({'is_source_interface' : tmp})
+
     return peth
 
 def verify(peth):