Initial commit moving openolt adapter from voltha-go to the new repo.
This version works with ponsim rather than openolt, this is temporary.
It is currently being fixed to work with openolt.

Change-Id: I34a800c98f050140b367e2d474b7aa8b79f34b9a
Signed-off-by: William Kurkian <wkurkian@cisco.com>
diff --git a/python/common/utils/nethelpers.py b/python/common/utils/nethelpers.py
new file mode 100644
index 0000000..7df7f9f
--- /dev/null
+++ b/python/common/utils/nethelpers.py
@@ -0,0 +1,88 @@
+#
+# Copyright 2017 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""
+Some network related convenience functions
+"""
+
+from netifaces import AF_INET
+
+import netifaces as ni
+import netaddr
+
+
+def _get_all_interfaces():
+    m_interfaces = []
+    for iface in ni.interfaces():
+        m_interfaces.append((iface, ni.ifaddresses(iface)))
+    return m_interfaces
+
+
+def _get_my_primary_interface():
+    gateways = ni.gateways()
+    assert 'default' in gateways, \
+        ("No default gateway on host/container, "
+         "cannot determine primary interface")
+    default_gw_index = gateways['default'].keys()[0]
+    # gateways[default_gw_index] has the format (example):
+    # [('10.15.32.1', 'en0', True)]
+    interface_name = gateways[default_gw_index][0][1]
+    return interface_name
+
+
+def get_my_primary_local_ipv4(inter_core_subnet=None, ifname=None):
+    if not inter_core_subnet:
+        return _get_my_primary_local_ipv4(ifname)
+    # My IP should belong to the specified subnet
+    for iface in ni.interfaces():
+        addresses = ni.ifaddresses(iface)
+        if AF_INET in addresses:
+            m_ip = addresses[AF_INET][0]['addr']
+            _ip = netaddr.IPAddress(m_ip).value
+            m_network = netaddr.IPNetwork(inter_core_subnet)
+            if _ip >= m_network.first and _ip <= m_network.last:
+                return m_ip
+    return None
+
+
+def get_my_primary_interface(pon_subnet=None):
+    if not pon_subnet:
+        return _get_my_primary_interface()
+    # My interface should have an IP that belongs to the specified subnet
+    for iface in ni.interfaces():
+        addresses = ni.ifaddresses(iface)
+        if AF_INET in addresses:
+            m_ip = addresses[AF_INET][0]['addr']
+            m_ip = netaddr.IPAddress(m_ip).value
+            m_network = netaddr.IPNetwork(pon_subnet)
+            if m_ip >= m_network.first and m_ip <= m_network.last:
+                return iface
+    return None
+
+def mac_str_to_tuple(mac):
+    return tuple(int(d, 16) for d in mac.split(':'))
+
+def _get_my_primary_local_ipv4(ifname=None):
+    try:
+        ifname = get_my_primary_interface() if ifname is None else ifname
+        addresses = ni.ifaddresses(ifname)
+        ipv4 = addresses[AF_INET][0]['addr']
+        return ipv4
+    except Exception as e:
+        return None
+
+if __name__ == '__main__':
+    print get_my_primary_local_ipv4()