Support VLAN devices

[fdellwing]

Hi,

we use VLAN devices (there are a lot of them in production) and sadly ifcfg is unable to parse them. I do not need any real information about the VLAN interfaces, but the script should not crash.

Python 3.7.4 (default, Sep 16 2019, 11:45:03) 
[GCC 4.9.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ifcfg
>>> ifcfg.interfaces()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/ifcfg/__init__.py", line 66, in interfaces
    return Parser(ifconfig=ifconfig).interfaces
  File "/usr/local/lib/python3.7/site-packages/ifcfg/parser.py", line 30, in __init__
    self.parse(self.ifconfig_data)
  File "/usr/local/lib/python3.7/site-packages/ifcfg/parser.py", line 70, in parse
    self.add_device(cur)
  File "/usr/local/lib/python3.7/site-packages/ifcfg/parser.py", line 34, in add_device
    raise RuntimeError("Device {} already added".format(device_name))
RuntimeError: Device eth2 already added

br2       Link encap:Ethernet  HWaddr 08:00:27:7c:6d:9d  
          inet addr:10.0.0.1  Bcast:10.0.0.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe7c:6d9d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:1528 (1.4 KiB)

br4       Link encap:Ethernet  HWaddr 08:00:27:7c:6d:9d  
          inet addr:10.0.2.1  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe7c:6d9d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:727 errors:0 dropped:0 overruns:0 frame:0
          TX packets:643 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:88547 (86.4 KiB)  TX bytes:890348 (869.4 KiB)

brlan     Link encap:Ethernet  HWaddr 08:00:27:d8:78:41  
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fed8:7841/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6905 errors:0 dropped:0 overruns:0 frame:0
          TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:351150 (342.9 KiB)  TX bytes:1568 (1.5 KiB)

eth0      Link encap:Ethernet  HWaddr 08:00:27:d8:78:41  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:7353 errors:0 dropped:433 overruns:0 frame:0
          TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:482610 (471.2 KiB)  TX bytes:1568 (1.5 KiB)

eth1      Link encap:Ethernet  HWaddr 08:00:27:f2:d0:cb  
          inet addr:172.16.25.205  Bcast:172.16.25.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fef2:d0cb/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:65901 errors:0 dropped:0 overruns:0 frame:0
          TX packets:36638 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:80272939 (76.5 MiB)  TX bytes:5598473 (5.3 MiB)

eth2      Link encap:Ethernet  HWaddr 08:00:27:7c:6d:9d  
          inet6 addr: fe80::a00:27ff:fe7c:6d9d/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:7200 errors:0 dropped:431 overruns:0 frame:0
          TX packets:111 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:471382 (460.3 KiB)  TX bytes:8368 (8.1 KiB)

eth2.2    Link encap:Ethernet  HWaddr 08:00:27:7c:6d:9d  
          inet6 addr: fe80::a00:27ff:fe7c:6d9d/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:2278 (2.2 KiB)

eth2.4    Link encap:Ethernet  HWaddr 08:00:27:7c:6d:9d  
          inet6 addr: fe80::a00:27ff:fe7c:6d9d/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:52 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:3704 (3.6 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:12786 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12786 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:1853178 (1.7 MiB)  TX bytes:1853178 (1.7 MiB)

tap2      Link encap:Ethernet  HWaddr ba:c7:a9:f5:ae:6b  
          inet6 addr: fe80::b8c7:a9ff:fef5:ae6b/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:41 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100 
          RX bytes:0 (0.0 B)  TX bytes:3146 (3.0 KiB)

tap4      Link encap:Ethernet  HWaddr 22:e9:b0:f5:6d:9d  
          inet addr:10.0.2.2  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::20e9:b0ff:fef5:6d9d/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:727 errors:0 dropped:0 overruns:0 frame:0
          TX packets:983 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100 
          RX bytes:98725 (96.4 KiB)  TX bytes:913020 (891.6 KiB)

[benjaoming]

Thanks for the report @fdellwing !

Guessing that the issue is that eth2.2 gets matched and added as eth2 which should crash, as it already exists... BUT it's the matching that's the problem. Assuming that . should be allowed in the pattern for interface names.

PR is absolutely welcomed :)