join: LDAP connection to remote DC can timeout in large join

When joining a very large domain (e.g. 100K users), the replication can
take so long that the LDAP connection to the remote DC times out.

This patch avoids the problem by adding in a sanity-check after the
replication finishes that the LDB connection is still alive. If not,
then we reconnect.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13612

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/python/samba/join.py b/python/samba/join.py
index 3869947f73713651adf8ee3397fd6dc6d9e2fe2d..6a9c3b9807ffb60e292f5521a69dddf2815521ce 100644 (file)
--- a/python/samba/join.py
+++ b/python/samba/join.py
@@ -1020,6 +1020,27 @@ class DCJoinContext(object):
         else:
             ctx.local_samdb.transaction_commit()
 
+        # A large replication may have caused our LDB connection to the
+        # remote DC to timeout, so check the connection is still alive
+        ctx.refresh_ldb_connection()
+
+    def refresh_ldb_connection(ctx):
+        try:
+            # query the rootDSE to check the connection
+            ctx.samdb.search(scope=ldb.SCOPE_BASE, attrs=[])
+        except ldb.LdbError as e:
+            (enum, estr) = e.args
+
+            # if the connection was disconnected, then reconnect
+            if (enum == ldb.ERR_OPERATIONS_ERROR and
+                'NT_STATUS_CONNECTION_DISCONNECTED' in estr):
+                ctx.logger.warning("LDB connection disconnected. Reconnecting")
+                ctx.samdb = SamDB(url="ldap://%s" % ctx.server,
+                                  session_info=system_session(),
+                                  credentials=ctx.creds, lp=ctx.lp)
+            else:
+                raise DCJoinException(estr)
+
     def send_DsReplicaUpdateRefs(ctx, dn):
         r = drsuapi.DsReplicaUpdateRefsRequest1()
         r.naming_context = drsuapi.DsReplicaObjectIdentifier()