udm_dns_record: Fix handling of PTR records (#3244) (#3256)

* udm_dns_record: Fix handling of PTR records (#3244)

Before, it was not possible to manage PTR records in Univention DNS,
due to broken zone lookups and improper used parameters of the object.
This patch fixes the PTR handling, allowing both v4 and v6 entries.

* udm_dns_record: [doc] add changelog fragment

* udm_dns_record: [fix] validation errors

* udm_dns_record: import ipaddress module conditionally (#3244)

* udm_dns_record: fix sanity check error, improve doc (#3244)

* udm_dns_record: Improve changes to meet community standards (#3244)

changelogs/fragments/3256-fix-ptr-handling-in-udm_dns_record.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - udm_dns_record - fixed managing of PTR records, which can never have worked before (https://github.com/ansible-collections/community.general/pull/3256).

plugins/modules/cloud/univention/udm_dns_record.py

@@ -21,6 +21,7 @@ description:
 requirements:
     - Python >= 2.6
     - Univention
+    - ipaddress (for I(type=ptr_record))
 options:
     state:
         type: str
@@ -34,11 +35,13 @@ options:
         description:
             - "Name of the record, this is also the DNS record. E.g. www for
                www.example.com."
+            - For PTR records this has to be the IP address.
     zone:
         type: str
         required: true
         description:
             - Corresponding DNS zone for this record, e.g. example.com.
+            - For PTR records this has to be the full reverse zone (for example C(1.1.192.in-addr.arpa)).
     type:
         type: str
         required: true
@@ -66,12 +69,29 @@ EXAMPLES = '''
       a:
          - 192.0.2.1
          - 2001:0db8::42
+
+- name: Create a DNS v4 PTR record on a UCS
+  community.general.udm_dns_record:
+    name: 192.0.2.1
+    zone: 2.0.192.in-addr.arpa
+    type: ptr_record
+    data:
+      ptr_record: "www.example.com."
+
+- name: Create a DNS v6 PTR record on a UCS
+  community.general.udm_dns_record:
+    name: 2001:db8:0:0:0:ff00:42:8329
+    zone: 2.4.0.0.0.0.f.f.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa
+    type: ptr_record
+    data:
+      ptr_record: "www.example.com."
 '''
 
 
 RETURN = '''#'''
 
 HAVE_UNIVENTION = False
+HAVE_IPADDRESS = False
 try:
     from univention.admin.handlers.dns import (
         forward_zone,
@@ -82,6 +102,7 @@ except ImportError:
     pass
 
 from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.basic import missing_required_lib
 from ansible_collections.community.general.plugins.module_utils.univention_umc import (
     umc_module_for_add,
     umc_module_for_edit,
@@ -90,6 +111,11 @@ from ansible_collections.community.general.plugins.module_utils.univention_umc i
     config,
     uldap,
 )
+try:
+    import ipaddress
+    HAVE_IPADDRESS = True
+except ImportError:
+    pass
 
 
 def main():
@@ -124,14 +150,30 @@ def main():
     changed = False
     diff = None
 
+    workname = name
+    if type == 'ptr_record':
+        if not HAVE_IPADDRESS:
+            module.fail_json(msg=missing_required_lib('ipaddress'))
+        try:
+            if 'arpa' not in zone:
+                raise Exception("Zone must be reversed zone for ptr_record. (e.g. 1.1.192.in-addr.arpa)")
+            ipaddr_rev = ipaddress.ip_address(name).reverse_pointer
+            subnet_offset = ipaddr_rev.find(zone)
+            if subnet_offset == -1:
+                raise Exception("reversed IP address {0} is not part of zone.".format(ipaddr_rev))
+            workname = ipaddr_rev[0:subnet_offset - 1]
+        except Exception as e:
+            module.fail_json(
+                msg='handling PTR record for {0} in zone {1} failed: {2}'.format(name, zone, e)
+            )
+
     obj = list(ldap_search(
-        '(&(objectClass=dNSZone)(zoneName={0})(relativeDomainName={1}))'.format(zone, name),
+        '(&(objectClass=dNSZone)(zoneName={0})(relativeDomainName={1}))'.format(zone, workname),
         attr=['dNSZone']
     ))
-
     exists = bool(len(obj))
     container = 'zoneName={0},cn=dns,{1}'.format(zone, base_dn())
-    dn = 'relativeDomainName={0},{1}'.format(name, container)
+    dn = 'relativeDomainName={0},{1}'.format(workname, container)
 
     if state == 'present':
         try:
@@ -144,13 +186,21 @@ def main():
                 ) or reverse_zone.lookup(
                     config(),
                     uldap(),
-                    '(zone={0})'.format(zone),
+                    '(zoneName={0})'.format(zone),
                     scope='domain',
                 )
+                if len(so) == 0:
+                    raise Exception("Did not find zone '{0}' in Univention".format(zone))
                 obj = umc_module_for_add('dns/{0}'.format(type), container, superordinate=so[0])
             else:
                 obj = umc_module_for_edit('dns/{0}'.format(type), dn)
-            obj['name'] = name
+
+            if type == 'ptr_record':
+                obj['ip'] = name
+                obj['address'] = workname
+            else:
+                obj['name'] = name
+
             for k, v in data.items():
                 obj[k] = v
             diff = obj.diff()