On 22.10.2015 16:59, Petr Spacek wrote:
On 16.10.2015 12:13, Martin Babinsky wrote:
On 10/14/2015 04:05 PM, Petr Spacek wrote:
On 14.10.2015 14:13, Martin Babinsky wrote:
On 10/13/2015 04:00 PM, Petr Spacek wrote:
On 13.10.2015 13:37, Martin Babinsky wrote:
On 10/13/2015 09:36 AM, Petr Spacek wrote:
On 12.10.2015 16:35, Martin Babinsky wrote:
     ipalib/plugins/dns.py | 3 ++-
     1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ipalib/plugins/dns.py b/ipalib/plugins/dns.py

--- a/ipalib/plugins/dns.py
+++ b/ipalib/plugins/dns.py
@@ -537,7 +537,8 @@ def get_reverse_zone(ipaddr, prefixlen=None):
         if prefixlen is None:
             revzone = None

-        result = api.Command['dnszone_find']()['result']
+        result = api.Command['dnszone_find'](sizelimit=0)['result']
NACK, this just increases the limit because LDAP server will enforce a
per-user limit.

             for zone in result:
                 zonename = zone['idnsname'][0]
                 if (revdns.is_subdomain(zonename.make_absolute()) and
Generic solution should use dns.resolver.zone_for_name() to find DNS zone
matching the reverse name. This should also implicitly cover CNAME/DNAME
redirections per RFC2317.

Using DNS implicitly means that a zone will always be found (at least the
zone :-). For this reason I would change final error message
reason=_('DNS reverse zone for IP address %(addr)s not found')
to something like:
      reason=_('DNS reverse zone %(zone)s for IP address %(addr)s is not
by this server')

These changes should fix it without adding other artificial limitation.

Thank you for clarification Petr.

Attaching the reworked patch.

Martin^3 Babinsky


   From 463903f4ea4f74efeb02dbb705ca0a54fab81366 Mon Sep 17 00:00:00 2001
From: Martin Babinsky <mbabi...@redhat.com>
Date: Mon, 12 Oct 2015 16:24:50 +0200
Subject: [PATCH 1/3] perform more robust search for reverse zones when
    DNS record

Instead of searching for all zones to identify the correct reverse zone, we
will first ask the resolver to return the name of zone that should
contain the
desired record and then see if IPA manages this zone.

    ipalib/plugins/dns.py | 21 +++++++++++++++++----
    1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/ipalib/plugins/dns.py b/ipalib/plugins/dns.py

--- a/ipalib/plugins/dns.py
+++ b/ipalib/plugins/dns.py
@@ -531,25 +531,35 @@ def add_forward_record(zone, name, str_address):
            pass # the entry already exists and matches

    def get_reverse_zone(ipaddr, prefixlen=None):
+    """
+    resolve the reverse zone for IP address and see if it is managed by IPA
+    server
+    :param ipaddr: host IP address
+    :param prefixlen: network prefix length
+    :return: tuple containing name of the reverse zone and the name of the
+    record
+    """
        ip = netaddr.IPAddress(str(ipaddr))
        revdns = DNSName(unicode(ip.reverse_dns))
+    resolved_zone = unicode(dns.resolver.zone_for_name(revdns))

        if prefixlen is None:
            revzone = None
+        result = api.Command['dnszone_find'](resolved_zone)['result']

-        result = api.Command['dnszone_find']()['result']
            for zone in result:
                zonename = zone['idnsname'][0]
                if (revdns.is_subdomain(zonename.make_absolute()) and
                   (revzone is None or zonename.is_subdomain(revzone))):
                    revzone = zonename
Oh, wait, this might blow up if there is a disabled DNS zone which is deeper
than the one returned from DNS query.

Damn, we have opened a Pandora box!

ipaserver/install/bindinstance.py has own implementation of
+ additional menthods find_reverse_zone().
These are using get_reverse_zone_default() from ipalib/util.py which is
duplicating code in 'if prefixlen is not None' branch.

And of course, are not correct in light of this change.

My expectation would be that disabled zones should be ignored... So we should
get rid of this mess in the loop and use dnszone_show() which is called at
end. And fix the other places, preferably by deleting duplicate

I would expect that you can store (converted) output of
dns.resolver.zone_for_name(revdns) into revzone and delete whole 'if
is None' branch.

+        # if prefixlen is specified, determine the zone name for the
+        # prefix
            if ip.version == 4:
                pos = 4 - prefixlen / 8
            elif ip.version == 6:
                pos = 32 - prefixlen / 4
-        items = ip.reverse_dns.split('.')
-        revzone = DNSName(items[pos:])
+        revzone = revdns[pos:]
Hmm, and this logic will breaks CNAME/DNAME (RFC2317) handling ... Damn, we
need different handling when we intend to create the zone and when we want to
manipulate a record in a reverse zone. Grrr.

When we want to manipulate a record in existing zone, the whole branch does
not make sense and the result of DNS query is what we want and need.

On the other hand, we need this when creating *a new zone* from IP address

Mastin^2, what about zone names with missing period at the end? Is it handled
by dnszone_show() internally?

We have to discuss all this...

@@ -558,7 +568,10 @@ def get_reverse_zone(ipaddr, prefixlen=None):

        if revzone is None:
            raise errors.NotFound(
-            reason=_('DNS reverse zone for IP address %(addr)s not found')
% dict(addr=ipaddr)
+            reason=_(
+                'DNS reverse zone %(resolved_zone)s for IP address '
+                '%(addr)s is not manager by this server') % dict(
typo s/manager/managed/

+                addr=ipaddr, resolved_zone=resolved_zone)

        revname = revdns.relativize(revzone)
After lengthy discussion with Petr^2 I we decided to rework get_reverse_zone
function a bit. Attaching updated patch.
Well, we should get rid of prefixlen parameter. Wipe it from Earth's
surface! :-)

The assumption here is that this function is always used only for manipulating
*records in existing zones*, so the only way to find appropriate reverse zone
name is to ask DNS.

Derivation based on prefix length makes sense only for deriving reverse zone
names from IP addresses *with intent to create the zone*.

In all other cases it does not make sense to use prefix. I'm sorry that I was
not clear.

Upon Thy request I purged the Function that Gets the Name of the Zone Reverse
of the crawling evil thee caleth the Prefixlen.

The shallow impostor of The Function whose services no Module required nor
used was also banished to oblivion and His noisome vapors shall bother the
Kingdom of Identity no more.

Thou shalt rejoice when Thy review the rewritten Patch attached herein or else
I shall be smitten by the mighty NACK thee wieldeth.
Mighty ACK! :-D

Thank you for your patience with me.

Pushed to:
ipa-4-2: 2d4854480c1457a77dde2a3ed53f464521dd7254
master: c43dce3a61e17791cc31f45498bae2d52edcf969

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