KCC: remove useless comments and simplify get_dsa_for_implied_replica()

These comments are a close reflection (or possibly copy/paste) of the
spec, but our code here no longer resembles the spec. We end up just
glazing over when we see comments and losing track of the flow of code.

If you want the spec just look at the spec.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 9 insertions, 32 deletions

diff --git a/python/samba/kcc/__init__.py b/python/samba/kcc/__init__.py
index 9e69b391407..015278f2196 100644
--- a/python/samba/kcc/__init__.py
+++ b/python/samba/kcc/__init__.py
@@ -800,14 +800,12 @@ class KCC(object):
         :param cn_conn: NTDS Connection
         :return: source DSA or None
         """
-        #XXX different conditions for "implies" than MS-ADTS 6.2.2
+        # XXX different conditions for "implies" than MS-ADTS 6.2.2
+        # preamble.
 
-        # NTDS Connection must satisfy all the following criteria
-        # to imply a repsFrom tuple is needed:
-        #
-        #    cn!enabledConnection = true.
-        #    cn!options does not contain NTDSCONN_OPT_RODC_TOPOLOGY.
-        #    cn!fromServer references an nTDSDSA object.
+        # It boils down to: we want an enabled, non-FRS connections to
+        # a valid remote DSA with a non-RO replica corresponding to
+        # n_rep.
 
         if not cn_conn.is_enabled() or cn_conn.is_rodc_topology():
             return None
@@ -819,36 +817,15 @@ class KCC(object):
         if s_dsa is None:
             return None
 
-        # To imply a repsFrom tuple is needed, each of these
-        # must be True:
-        #
-        #     An NC replica of the NC "is present" on the DC to
-        #     which the nTDSDSA object referenced by cn!fromServer
-        #     corresponds.
-        #
-        #     An NC replica of the NC "should be present" on
-        #     the local DC
         s_rep = s_dsa.get_current_replica(n_rep.nc_dnstr)
 
-        if s_rep is None or not s_rep.is_present():
-            return None
-
-        # To imply a repsFrom tuple is needed, each of these
-        # must be True:
-        #
-        #     The NC replica on the DC referenced by cn!fromServer is
-        #     a writable replica or the NC replica that "should be
-        #     present" on the local DC is a partial replica.
-        #
-        #     The NC is not a domain NC, the NC replica that
-        #     "should be present" on the local DC is a partial
-        #     replica, cn!transportType has no value, or
-        #     cn!transportType has an RDN of CN=IP.
-        #
-        if not s_rep.is_ro() or n_rep.is_partial():
+        if (s_rep is not None and
+            s_rep.is_present() and
+            (not s_rep.is_ro() or n_rep.is_partial())):
             return s_dsa
         return None
 
+
     def translate_ntdsconn(self, current_dsa=None):
         """Adjust repsFrom to match NTDSConnections