# HG changeset patch
# User Søren Løvborg <soeren.j.loevborg@siemens.com>
# Date 1416933862 -3600
#      Tue Nov 25 17:44:22 2014 +0100
# Node ID a79d4a814ccf2db2281d769f69c6acef8a176f97
# Parent  32d08aacffe063f0d11ac2dcdec48678858eeea9
Issue #22941: Sensible IPv[46]Interface arithmetic

diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -1074,6 +1074,24 @@
                 self.broadcast_address.is_loopback)
 
 
+class _BaseInterface:
+
+    """ Base Interface object.
+
+        The following methods apply to both IPv4 and IPv6 interfaces.
+    """
+
+    def __add__(self, other):
+        if not isinstance(other, int):
+            return NotImplemented
+        return self.__class__((int(self) + other, self._prefixlen))
+
+    def __sub__(self, other):
+        if not isinstance(other, int):
+            return NotImplemented
+        return self.__class__((int(self) - other, self._prefixlen))
+
+
 class _BaseV4:
 
     """Base IPv4 object.
@@ -1382,7 +1400,7 @@
         return self in self._constants._linklocal_network
 
 
-class IPv4Interface(IPv4Address):
+class IPv4Interface(_BaseInterface, IPv4Address):
 
     def __init__(self, address):
         if isinstance(address, (bytes, int)):
@@ -2074,7 +2092,7 @@
         return IPv4Address((self._ip >> 80) & 0xFFFFFFFF)
 
 
-class IPv6Interface(IPv6Address):
+class IPv6Interface(_BaseInterface, IPv6Address):
 
     def __init__(self, address):
         if isinstance(address, (bytes, int)):