From 6c9b9ad2690902a348a7f6ea7a5533efcd628c78 Mon Sep 17 00:00:00 2001
From: Jeff Ferland <jeff@storyinmemo.com>
Date: Tue, 19 Mar 2013 15:54:11 -0700
Subject: [PATCH] Fix several issues with adding IP ranges

* Prevents non-adjacent ranges from being added
* Prevents creating invalid subnets
* Fixes a bug where the integer value of an IPv6 address that is less than
  32 bits would be treated as an IPv4 address during addition.
---
 ChangeLog        |  6 ++++++
 IPy.py           | 13 +++++++++----
 test/test_IPy.py |  6 ++++++
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9d9cfa9..2782c7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,12 @@ Version 0.80
 
 * Drop support of Python older than 2.4
 * Python 3 does not need 2to3 conversion anymore (same code base)
+* Fix adding of non-adjacent networks
+   192.168.0.0/24 + 192.168.255.0/24 made 192.168.0.0/23
+* Fix adding networks that don't create a valid subnet
+   192.168.1.0/24 + 192.168.2.0/24 made 192.168.1.0/23
+* Fix adding with an IPv6 address where .int() was < 32 bits made IPy believe it
+  was an IPv4 address.
 
 Version 0.76 (2013-03-19)
 -------------------------
diff --git a/IPy.py b/IPy.py
index e83f8d0..a0d4203 100644
--- a/IPy.py
+++ b/IPy.py
@@ -977,10 +977,15 @@ def __add__(self, other):
         if self > other:
             # fixed by Skinny Puppy <skin_pup-IPy@happypoo.com>
             return other.__add__(self)
-        else:
-            ret = IP(self.int())
-            ret._prefixlen = self.prefixlen() - 1
-            return ret
+        if other.int() - self[-1].int() != 1:
+            raise ValueError("Only adjacent networks can be added together.")
+        ret = IP(self.int(), ipversion=self._ipversion)
+        ret._prefixlen = self.prefixlen() - 1
+        if not _checkNetaddrWorksWithPrefixlen(ret.ip, ret._prefixlen,
+                                               ret._ipversion):
+            raise ValueError("The resulting %s has invalid prefix length (%s)"
+                             % (repr(ret), ret._prefixlen))
+        return ret
 
     def get_mac(self):
         """
diff --git a/test/test_IPy.py b/test/test_IPy.py
index c35b69f..60b722f 100644
--- a/test/test_IPy.py
+++ b/test/test_IPy.py
@@ -715,7 +715,12 @@ def testMisc(self):
 
         ip = IPy.IP('133.45.0/24')
         ip2 = IPy.IP('133.45.1/24')
+        ip3 = IPy.IP('133.45.2/24')
         self.assertEqual((ip + ip2).prefixlen(),23)
+        # Non-adjacent ranges
+        self.assertRaises(ValueError, IPy.IP.__add__, ip, ip3)
+        # Resulting invalid prefix
+        self.assertRaises(ValueError, IPy.IP.__add__, ip2, ip3)
 
         ip2 = IPy.IP('133.44.255.255');
         #$T->ok_eqnum ($ip->bincomp('gt',$ip2),1,$ip->error());
@@ -756,6 +761,7 @@ def testMisc(self):
         ip = IPy.IP('::e000:0/112')
         ip2 = IPy.IP('::e001:0/112')
         self.assertEqual(ip.__add__(ip2).prefixlen(),111)
+        self.assertEqual(ip.__add__(ip2).version(),6)
 
         ip2 = IPy.IP('::dfff:ffff')
         #$T->ok_eqnum ($ip->bincomp('gt',$ip2),1,$ip->error());