vyos.ifconfig: T7018: drop 'iftype' class attribute (#4280)

Under very rare cases we can run into a race condition where interfaces are
still in creation phase but are already referenced..

This can trigger:

  File "/usr/libexec/vyos/conf_mode/system_conntrack.py", line 270, in <module>
    apply(c)
  File "/usr/libexec/vyos/conf_mode/system_conntrack.py", line 249, in apply
    call_dependents()
  File "/usr/lib/python3/dist-packages/vyos/configdep.py", line 147, in call_dependents
    f()
  File "/usr/lib/python3/dist-packages/vyos/configdep.py", line 118, in func_impl
    run_config_mode_script(script, config)
  File "/usr/lib/python3/dist-packages/vyos/configdep.py", line 106, in run_config_mode_script
    mod.verify(c)
  File "/usr/libexec/vyos//conf_mode/service_conntrack-sync.py", line 72, in verify
    if len(get_ipv4(interface)) < 1:
           ^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/vyos/template.py", line 458, in get_ipv4
    return Interface(interface).get_addr_v4()
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 334, in __init__
    if not self.iftype:
    ^^^^^^^^^^^

  AttributeError: 'Interface' object has no attribute 'iftype'

This commit removes the code path in question and the class attribute check.
The reason for the iftype attribute in the past was a common _create() method
serving for all interface types. As we already have a lot of derived
implementations and not all honor the classes iftype/type member - or even
worse honor it only in 50% of the occurrences it's time to drop it.

python/vyos/ifconfig/bond.py

@@ -31,7 +31,6 @@ class BondIf(Interface):
     monitoring may be performed.
     """
 
-    iftype = 'bond'
     definition = {
         **Interface.definition,
         ** {
@@ -109,6 +108,9 @@ def get_inherit_bond_options() -> list:
         ]
         return options
 
+    def _create(self):
+        super()._create('bond')
+
     def remove(self):
         """
         Remove interface from operating system. Removing the interface

python/vyos/ifconfig/bridge.py

@@ -32,7 +32,6 @@ class BridgeIf(Interface):
 
     The Linux bridge code implements a subset of the ANSI/IEEE 802.1d standard.
     """
-    iftype = 'bridge'
     definition = {
         **Interface.definition,
         **{
@@ -107,6 +106,9 @@ class BridgeIf(Interface):
         },
     }}
 
+    def _create(self):
+        super()._create('bridge')
+
     def get_vlan_filter(self):
         """
         Get the status of the bridge VLAN filter

python/vyos/ifconfig/dummy.py

@@ -22,12 +22,13 @@ class DummyIf(Interface):
     interface. The purpose of a dummy interface is to provide a device to route
     packets through without actually transmitting them.
     """
-
-    iftype = 'dummy'
     definition = {
         **Interface.definition,
         **{
             'section': 'dummy',
             'prefixes': ['dum', ],
         },
     }
+
+    def _create(self):
+        super()._create('dummy')

python/vyos/ifconfig/ethernet.py

@@ -33,7 +33,6 @@ class EthernetIf(Interface):
     Abstraction of a Linux Ethernet Interface
     """
 
-    iftype = 'ethernet'
     definition = {
         **Interface.definition,
         **{
@@ -119,6 +118,9 @@ def __init__(self, ifname, **kargs):
         super().__init__(ifname, **kargs)
         self.ethtool = Ethtool(ifname)
 
+    def _create(self):
+        pass
+
     def remove(self):
         """
         Remove interface from config. Removing the interface deconfigures all
@@ -137,7 +139,7 @@ def remove(self):
         # Remove all VLAN subinterfaces - filter with the VLAN dot
         for vlan in [
             x
-            for x in Section.interfaces(self.iftype)
+            for x in Section.interfaces('ethernet')
             if x.startswith(f'{self.ifname}.')
         ]:
             Interface(vlan).remove()

python/vyos/ifconfig/geneve.py

@@ -27,7 +27,6 @@ class GeneveIf(Interface):
     https://developers.redhat.com/blog/2019/05/17/an-introduction-to-linux-virtual-interfaces-tunnels/#geneve
     https://lwn.net/Articles/644938/
     """
-    iftype = 'geneve'
     definition = {
         **Interface.definition,
         **{
@@ -49,7 +48,7 @@ def _create(self):
             'parameters.ipv6.flowlabel'  : 'flowlabel',
         }
 
-        cmd = 'ip link add name {ifname} type {type} id {vni} remote {remote}'
+        cmd = 'ip link add name {ifname} type geneve id {vni} remote {remote}'
         for vyos_key, iproute2_key in mapping.items():
             # dict_search will return an empty dict "{}" for valueless nodes like
             # "parameters.nolearning" - thus we need to test the nodes existence

python/vyos/ifconfig/input.py

@@ -25,12 +25,13 @@ class InputIf(Interface):
     a single stack of qdiscs, classes and filters can be shared between
     multiple interfaces.
     """
-
-    iftype = 'ifb'
     definition = {
         **Interface.definition,
         **{
             'section': 'input',
             'prefixes': ['ifb', ],
         },
     }
+
+    def _create(self):
+        super()._create('ifb')

python/vyos/ifconfig/interface.py

@@ -29,7 +29,6 @@
 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
@@ -74,7 +73,6 @@ class Interface(Control):
     OperationalClass = Operational
 
     options = ['debug', 'create']
-    required = []
     default = {
         'debug': True,
         'create': True,
@@ -336,22 +334,10 @@ def __init__(self, ifname, **kargs):
         super().__init__(**kargs)
 
         if not self.exists(ifname):
-            # Any instance of Interface, such as Interface('eth0') can be used
-            # safely to access the generic function in this class as 'type' is
-            # unset, the class can not be created
-            if not hasattr(self, 'iftype'):
-                raise ConfigError(f'Interface "{ifname}" has no "iftype" attribute defined!')
-            self.config['type'] = self.iftype
-
             # Should an Instance of a child class (EthernetIf, DummyIf, ..)
             # be required, then create should be set to False to not accidentally create it.
             # In case a subclass does not define it, we use get to set the default to True
-            if self.config.get('create',True):
-                for k in self.required:
-                    if k not in kargs:
-                        name = self.default['type']
-                        raise ConfigError(f'missing required option {k} for {name} {ifname} creation')
-
+            if self.config.get('create', True):
                 self._create()
             # If we can not connect to the interface then let the caller know
             # as the class could not be correctly initialised
@@ -364,13 +350,14 @@ def __init__(self, ifname, **kargs):
         self.operational = self.OperationalClass(ifname)
         self.vrrp = VRRP(ifname)
 
-    def _create(self):
+    def _create(self, type: str=''):
         # Do not create interface that already exist or exists in netns
         netns = self.config.get('netns', None)
         if self.exists(f'{self.ifname}', netns=netns):
             return
 
-        cmd = 'ip link add dev {ifname} type {type}'.format(**self.config)
+        cmd = f'ip link add dev {self.ifname}'
+        if type: cmd += f' type {type}'
         if 'netns' in self.config: cmd = f'ip netns exec {netns} {cmd}'
         self._cmd(cmd)
 
@@ -1954,8 +1941,6 @@ def update(self, config):
 
 class VLANIf(Interface):
     """ Specific class which abstracts 802.1q and 802.1ad (Q-in-Q) VLAN interfaces """
-    iftype = 'vlan'
-
     def _create(self):
         # bail out early if interface already exists
         if self.exists(f'{self.ifname}'):

python/vyos/ifconfig/l2tpv3.py

@@ -45,7 +45,6 @@ class L2TPv3If(Interface):
     either hot standby or load balancing services. Additionally, link integrity
     monitoring may be performed.
     """
-    iftype = 'l2tp'
     definition = {
         **Interface.definition,
         **{

python/vyos/ifconfig/loopback.py

@@ -22,16 +22,20 @@ class LoopbackIf(Interface):
     uses to communicate with itself.
     """
     _persistent_addresses = ['127.0.0.1/8', '::1/128']
-    iftype = 'loopback'
     definition = {
         **Interface.definition,
         **{
             'section': 'loopback',
             'prefixes': ['lo', ],
             'bridgeable': True,
+            'eternal': 'lo$',
         }
     }
 
+    def _create(self):
+        # we can not create this interface as it is managed by the Kernel
+        pass
+
     def remove(self):
         """
         Loopback interface can not be deleted from operating system. We can

python/vyos/ifconfig/macsec.py

@@ -27,7 +27,6 @@ class MACsecIf(Interface):
     other security solutions such as IPsec (layer 3) or TLS (layer 4), as all
     those solutions are used for their own specific use cases.
     """
-    iftype = 'macsec'
     definition = {
         **Interface.definition,
         **{
@@ -43,7 +42,7 @@ def _create(self):
         """
 
         # create tunnel interface
-        cmd  = 'ip link add link {source_interface} {ifname} type {type}'.format(**self.config)
+        cmd  = 'ip link add link {source_interface} {ifname} type macsec'.format(**self.config)
         cmd += f' cipher {self.config["security"]["cipher"]}'
 
         if 'encrypt' in self.config["security"]:

python/vyos/ifconfig/macvlan.py

@@ -20,7 +20,6 @@ class MACVLANIf(Interface):
     """
     Abstraction of a Linux MACvlan interface
     """
-    iftype = 'macvlan'
     definition = {
         **Interface.definition,
         **{
@@ -35,12 +34,12 @@ def _create(self):
         down by default.
         """
         # please do not change the order when assembling the command
-        cmd = 'ip link add {ifname} link {source_interface} type {type} mode {mode}'
+        cmd = 'ip link add {ifname} link {source_interface} type macvlan mode {mode}'
         self._cmd(cmd.format(**self.config))
 
         # interface is always A/D down. It needs to be enabled explicitly
         self.set_admin_state('down')
 
     def set_mode(self, mode):
-        cmd = f'ip link set dev {self.ifname} type {self.iftype} mode {mode}'
+        cmd = f'ip link set dev {self.ifname} type macvlan mode {mode}'
         return self._cmd(cmd)

python/vyos/ifconfig/pppoe.py

@@ -19,7 +19,6 @@
 
 @Interface.register
 class PPPoEIf(Interface):
-    iftype = 'pppoe'
     definition = {
         **Interface.definition,
         **{

python/vyos/ifconfig/sstpc.py

@@ -17,7 +17,6 @@
 
 @Interface.register
 class SSTPCIf(Interface):
-    iftype = 'sstpc'
     definition = {
         **Interface.definition,
         **{

python/vyos/ifconfig/tunnel.py

@@ -90,9 +90,8 @@ def __init__(self, ifname, **kargs):
         # T3357: we do not have the 'encapsulation' in kargs when calling this
         # class from op-mode like "show interfaces tunnel"
         if 'encapsulation' in kargs:
-            self.iftype = kargs['encapsulation']
             # The gretap interface has the possibility to act as L2 bridge
-            if self.iftype in ['gretap', 'ip6gretap']:
+            if kargs['encapsulation'] in ['gretap', 'ip6gretap']:
                 # no multicast, ttl or tos for gretap
                 self.definition = {
                     **TunnelIf.definition,
@@ -110,10 +109,10 @@ def _create(self):
             mapping = { **self.mapping, **self.mapping_ipv4 }
 
         cmd = 'ip tunnel add {ifname} mode {encapsulation}'
-        if self.iftype in ['gretap', 'ip6gretap', 'erspan', 'ip6erspan']:
+        if self.config['encapsulation'] in ['gretap', 'ip6gretap', 'erspan', 'ip6erspan']:
             cmd = 'ip link add name {ifname} type {encapsulation}'
             # ERSPAN requires the serialisation of packets
-            if self.iftype in ['erspan', 'ip6erspan']:
+            if self.config['encapsulation'] in ['erspan', 'ip6erspan']:
                 cmd += ' seq'
 
         for vyos_key, iproute2_key in mapping.items():
@@ -132,7 +131,7 @@ def _create(self):
 
     def _change_options(self):
         # gretap interfaces do not support changing any parameter
-        if self.iftype in ['gretap', 'ip6gretap', 'erspan', 'ip6erspan']:
+        if self.config['encapsulation'] in ['gretap', 'ip6gretap', 'erspan', 'ip6erspan']:
             return
 
         if self.config['encapsulation'] in ['ipip6', 'ip6ip6', 'ip6gre']:

python/vyos/ifconfig/veth.py

@@ -21,7 +21,6 @@ class VethIf(Interface):
     """
     Abstraction of a Linux veth interface
     """
-    iftype = 'veth'
     definition = {
         **Interface.definition,
         **{
@@ -46,7 +45,7 @@ def _create(self):
             return
 
         # create virtual-ethernet interface
-        cmd = 'ip link add {ifname} type {type}'.format(**self.config)
+        cmd = f'ip link add {self.ifname} type veth'
         cmd += f' peer name {self.config["peer_name"]}'
         self._cmd(cmd)
 

python/vyos/ifconfig/vrrp.py

@@ -26,15 +26,12 @@
 from vyos.utils.file import wait_for_file_write_complete
 from vyos.utils.process import process_running
 
-
 class VRRPError(Exception):
     pass
 
-
 class VRRPNoData(VRRPError):
     pass
 
-
 class VRRP(object):
     _vrrp_prefix = '00:00:5E:00:01:'
     location = {

python/vyos/ifconfig/vti.py

@@ -19,7 +19,6 @@
 
 @Interface.register
 class VTIIf(Interface):
-    iftype = 'vti'
     definition = {
         **Interface.definition,
         **{

python/vyos/ifconfig/vtun.py

@@ -17,7 +17,6 @@
 
 @Interface.register
 class VTunIf(Interface):
-    iftype = 'vtun'
     definition = {
         **Interface.definition,
         **{

python/vyos/ifconfig/vxlan.py

@@ -42,8 +42,6 @@ class VXLANIf(Interface):
     For more information please refer to:
     https://www.kernel.org/doc/Documentation/networking/vxlan.txt
     """
-
-    iftype = 'vxlan'
     definition = {
         **Interface.definition,
         **{
@@ -94,7 +92,7 @@ def _create(self):
             remote_list = self.config['remote'][1:]
             self.config['remote'] = self.config['remote'][0]
 
-        cmd = 'ip link add {ifname} type {type} dstport {port}'
+        cmd = 'ip link add {ifname} type vxlan dstport {port}'
         for vyos_key, iproute2_key in mapping.items():
             # dict_search will return an empty dict "{}" for valueless nodes like
             # "parameters.nolearning" - thus we need to test the nodes existence

python/vyos/ifconfig/wireguard.py

@@ -26,7 +26,6 @@
 from vyos.ifconfig import Operational
 from vyos.template import is_ipv6
 
-
 class WireGuardOperational(Operational):
     def _dump(self):
         """Dump wireguard data in a python friendly way."""
@@ -160,18 +159,18 @@ def show_interface(self):
 @Interface.register
 class WireGuardIf(Interface):
     OperationalClass = WireGuardOperational
-    iftype = 'wireguard'
     definition = {
         **Interface.definition,
         **{
             'section': 'wireguard',
-            'prefixes': [
-                'wg',
-            ],
+            'prefixes': ['wg', ],
             'bridgeable': False,
         },
     }
 
+    def _create(self):
+        super()._create('wireguard')
+
     def get_mac(self):
         """Get a synthetic MAC address."""
         return self.get_mac_synthetic()