1 files changed, 45 insertions, 4 deletions

diff --git a/os_net_config/utils.py b/os_net_config/utils.py
index cd7ee65..e51d197 100644
--- a/os_net_config/utils.py
+++ b/os_net_config/utils.py
@@ -14,35 +14,76 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import glob
 import logging
 
 
 logger = logging.getLogger(__name__)
+_SYS_CLASS_NET = '/sys/class/net'
 
 
 def write_config(filename, data):
-    with open(filename, "w") as f:
+    with open(filename, 'w') as f:
         f.write(str(data))
 
 
 def get_file_data(filename):
     try:
-        with open(filename, "r") as f:
+        with open(filename, 'r') as f:
             return f.read()
     except IOError:
         logger.error("Error reading file: %s" % filename)
-        return ""
+        return ''
 
 
 def interface_mac(name):
     try:
-        with open('/sys/class/net/%s/address' % name, "r") as f:
+        with open('/sys/class/net/%s/address' % name, 'r') as f:
             return f.read().rstrip()
     except IOError:
         logger.error("Unable to read file: %s" % name)
         raise
 
 
+def _is_active_nic(interface_name):
+    try:
+        if interface_name == 'lo':
+            return False
+
+        addr_assign_type = None
+        with open(_SYS_CLASS_NET + '/%s/addr_assign_type' % interface_name,
+                  'r') as f:
+            addr_assign_type = int(f.read().rstrip())
+
+        carrier = None
+        with open(_SYS_CLASS_NET + '/%s/carrier' % interface_name, 'r') as f:
+            carrier = int(f.read().rstrip())
+
+        address = None
+        with open(_SYS_CLASS_NET + '/%s/address' % interface_name, 'r') as f:
+            address = f.read().rstrip()
+
+        if addr_assign_type == 0 and carrier == 1 and address:
+            return True
+        else:
+            return False
+    except IOError:
+        return False
+
+
+def ordered_active_nics():
+    embedded_nics = []
+    nics = []
+    for name in glob.iglob(_SYS_CLASS_NET + '/*'):
+        nic = name[(len(_SYS_CLASS_NET) + 1):]
+        if _is_active_nic(nic):
+            if nic.startswith('em') or nic.startswith('eth'):
+                embedded_nics.append(nic)
+            else:
+                nics.append(nic)
+    return sorted(embedded_nics) + sorted(nics)
+
+
 def diff(filename, data):
     file_data = get_file_data(filename)
     logger.debug("Diff file data:\n%s" % file_data)