dns: Check if domain already exists.

Raise an error when the domain already exists. This can be overriden using
--force or --allow-zone-overlap options.

https://fedorahosted.org/freeipa/ticket/3681

Reviewed-By: Petr Spacek <pspacek@redhat.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/ipapython/ipautil.py b/ipapython/ipautil.py
index 4cee81e64..7509f08c1 100644
--- a/ipapython/ipautil.py
+++ b/ipapython/ipautil.py
@@ -40,7 +40,7 @@ from contextlib import contextmanager
 import locale
 import collections
 
-from dns import resolver, rdatatype
+from dns import resolver, rdatatype, reversename
 from dns.exception import DNSException, Timeout
 import six
 from six.moves import input
@@ -1031,6 +1031,22 @@ def host_exists(host):
         return True
 
 
+def reverse_record_exists(ip_address):
+    """
+    Checks if IP address have some reverse record somewhere.
+    Does not care where it points.
+
+    Returns True/False
+    """
+    reverse = reversename.from_address(str(ip_address))
+    try:
+        resolver.query(reverse, "PTR")
+    except DNSException:
+        # really don't care what exception, PTR is simply unresolvable
+        return False
+    return True
+
+
 def check_zone_overlap(zone, raise_on_timeout=True):
     root_logger.info("Checking DNS domain %s, please wait ..." % zone)
     if not isinstance(zone, DNSName):