Keep regex as default but still allow overrides.
diff --git a/_modules/linux_netlink.py b/_modules/linux_netlink.py
new file mode 100644
index 0000000..b1a3c17
--- /dev/null
+++ b/_modules/linux_netlink.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+
+import re
+
+
+def ls(regex=r'^[a-z0-9]+$'):
+ """
+ Provide a list of network interfaces.
+ """
+ _lo_re = re.compile(r'^lo$')
+ _alphanum_re = re.compile(regex)
+
+ def _filter(interface):
+ return _alphanum_re.match(interface) and not _lo_re.match(interface)
+
+ return filter(_filter, __salt__['grains.get']('ip_interfaces', {}).keys())