Check for IPv6 file before reading

Check to see if the IPv6 disabled flag file exists
before trying to read it. This file doesn't exist
on systems with the IPv6 module blacklisted.

Closes-Bug: #1361542
Change-Id: I4064b4189cc9d8f0f0e0e7025cf6f83d5b6ec276

diff --git a/neutron/common/ipv6_utils.py b/neutron/common/ipv6_utils.py
index 21b86acae192d34eeb58367a820e12d9235af376..96e1ef23440e67b47cdc43023426fdf15b1374d3 100644 (file)
--- a/neutron/common/ipv6_utils.py
+++ b/neutron/common/ipv6_utils.py
@@ -16,10 +16,15 @@
 """
 IPv6-related utilities and helper functions.
 """
+import os
 
 import netaddr
 
+from neutron.openstack.common.gettextutils import _LI
+from neutron.openstack.common import log
 
+
+LOG = log.getLogger(__name__)
 _IS_IPV6_ENABLED = None
 
 
@@ -47,7 +52,12 @@ def is_enabled():
 
     if _IS_IPV6_ENABLED is None:
         disabled_ipv6_path = "/proc/sys/net/ipv6/conf/default/disable_ipv6"
-        with open(disabled_ipv6_path, 'r') as f:
-            disabled = f.read().strip()
-        _IS_IPV6_ENABLED = disabled == "0"
+        if os.path.exists(disabled_ipv6_path):
+            with open(disabled_ipv6_path, 'r') as f:
+                disabled = f.read().strip()
+            _IS_IPV6_ENABLED = disabled == "0"
+        else:
+            _IS_IPV6_ENABLED = False
+        if not _IS_IPV6_ENABLED:
+            LOG.info(_LI("IPv6 is not enabled on this system."))
     return _IS_IPV6_ENABLED