summaryrefslogtreecommitdiff
path: root/source4/rpc_server/drsuapi/getncchanges.c
blob: 90ddab083c703e45df5a9b870215375770d438d9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
/* 
   Unix SMB/CIFS implementation.

   implement the DRSUpdateRefs call

   Copyright (C) Anatoliy Atanasov 2009
   Copyright (C) Andrew Tridgell 2009
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "librpc/gen_ndr/ndr_drsuapi.h"
#include "rpc_server/dcerpc_server.h"
#include "dsdb/samdb/samdb.h"
#include "param/param.h"
#include "librpc/gen_ndr/ndr_drsblobs.h"
#include "auth/auth.h"
#include "rpc_server/drsuapi/dcesrv_drsuapi.h"
#include "rpc_server/dcerpc_server_proto.h"
#include "../libcli/drsuapi/drsuapi.h"
#include "libcli/security/security.h"

/* 
  drsuapi_DsGetNCChanges for one object
*/
static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItemEx *obj,
					  struct ldb_message *msg,
					  struct ldb_context *sam_ctx,
					  struct ldb_dn *ncRoot_dn,
					  struct dsdb_schema *schema,
					  DATA_BLOB *session_key,
					  uint64_t highest_usn,
					  uint32_t replica_flags)
{
	const struct ldb_val *md_value;
	int i, n;
	struct ldb_dn *obj_dn;
	struct replPropertyMetaDataBlob md;
	struct dom_sid *sid;
	uint32_t rid = 0;
	enum ndr_err_code ndr_err;
	uint32_t *attids;
	const char *rdn;
	const struct dsdb_attribute *rdn_sa;

	if (ldb_dn_compare(ncRoot_dn, msg->dn) == 0) {
		obj->is_nc_prefix = true;
		obj->parent_object_guid = NULL;
	} else {
		struct ldb_dn *parent_dn;
		uint32_t instance_type;

		instance_type = ldb_msg_find_attr_as_uint(msg, "instanceType", 0);
		if (instance_type & INSTANCE_TYPE_IS_NC_HEAD) {
			struct ldb_result *res;
			int ret;
			const char *dnstr = ldb_dn_get_linearized(msg->dn);
			msg->dn = ldb_dn_new(msg, sam_ctx, dnstr);
			/* we need to re-search the msg, to avoid the
			 * broken dual message problems with our
			 * partitions implementation */
			DEBUG(6,(__location__ ": Re-fetching subref %s\n", 
				 ldb_dn_get_linearized(msg->dn)));
			ret = drsuapi_search_with_extended_dn(sam_ctx, msg, &res,
							      msg->dn, LDB_SCOPE_BASE, NULL,
							      NULL, NULL);
			if (ret != LDB_SUCCESS || res->count < 1) {
				DEBUG(0,(__location__ ": Failed to reload subref head %s in %s\n",
					 ldb_dn_get_linearized(msg->dn), ldb_dn_get_linearized(ncRoot_dn)));
				return WERR_DS_DRA_INTERNAL_ERROR;
			}
			msg = res->msgs[0];
		}

		parent_dn = ldb_dn_copy(msg, msg->dn);
		obj->is_nc_prefix = false;
		obj->parent_object_guid = talloc(obj, struct GUID);
		if (parent_dn == NULL) {
			return WERR_DS_DRA_INTERNAL_ERROR;
		}
		if (ldb_dn_remove_child_components(parent_dn, 1) != true) {
			DEBUG(0,(__location__ ": Unable to remove DN component\n"));
			return WERR_DS_DRA_INTERNAL_ERROR;
		}
		if (dsdb_find_guid_by_dn(sam_ctx, parent_dn, obj->parent_object_guid) != LDB_SUCCESS) {
			DEBUG(0,(__location__ ": Unable to find parent DN %s %s\n", 
				 ldb_dn_get_linearized(msg->dn), ldb_dn_get_linearized(parent_dn)));
		}
		talloc_free(parent_dn);
	}
	obj->next_object = NULL;
	
	md_value = ldb_msg_find_ldb_val(msg, "replPropertyMetaData");
	if (!md_value) {
		/* nothing to send */
		return WERR_OK;
	}

	ndr_err = ndr_pull_struct_blob(md_value, obj,
				       lp_iconv_convenience(ldb_get_opaque(sam_ctx, "loadparm")), &md,
				       (ndr_pull_flags_fn_t)ndr_pull_replPropertyMetaDataBlob);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		return WERR_DS_DRA_INTERNAL_ERROR;
	}
	
	if (md.version != 1) {
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	rdn = ldb_dn_get_rdn_name(msg->dn);
	if (rdn == NULL) {
		DEBUG(0,(__location__ ": No rDN for %s\n", ldb_dn_get_linearized(msg->dn)));
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	rdn_sa = dsdb_attribute_by_lDAPDisplayName(schema, rdn);
	if (rdn_sa == NULL) {
		DEBUG(0,(__location__ ": Can't find dsds_attribute for rDN %s in %s\n", 
			 rdn, ldb_dn_get_linearized(msg->dn)));
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	obj->meta_data_ctr = talloc(obj, struct drsuapi_DsReplicaMetaDataCtr);
	attids = talloc_array(obj, uint32_t, md.ctr.ctr1.count);
	
	obj->meta_data_ctr->meta_data = talloc_array(obj, struct drsuapi_DsReplicaMetaData, md.ctr.ctr1.count);
	for (n=i=0; i<md.ctr.ctr1.count; i++) {
		/* if the attribute has not changed, and it is not the
		   instanceType then don't include it */
		if (md.ctr.ctr1.array[i].local_usn < highest_usn &&
		    md.ctr.ctr1.array[i].attid != DRSUAPI_ATTRIBUTE_instanceType) continue;

		/* don't include the rDN */
		if (md.ctr.ctr1.array[i].attid == rdn_sa->attributeID_id) continue;

		obj->meta_data_ctr->meta_data[n].originating_change_time = md.ctr.ctr1.array[i].originating_change_time;
		obj->meta_data_ctr->meta_data[n].version = md.ctr.ctr1.array[i].version;
		obj->meta_data_ctr->meta_data[n].originating_invocation_id = md.ctr.ctr1.array[i].originating_invocation_id;
		obj->meta_data_ctr->meta_data[n].originating_usn = md.ctr.ctr1.array[i].originating_usn;
		attids[n] = md.ctr.ctr1.array[i].attid;
		n++;
	}

	/*
	  note that if n==0 we still need to send the change, as it
	  could be a rename, which changes the uSNChanged, but not any
	  of the replicated attributes
	 */

	obj->meta_data_ctr->count = n;

	obj->object.identifier = talloc(obj, struct drsuapi_DsReplicaObjectIdentifier);
	obj_dn = ldb_msg_find_attr_as_dn(sam_ctx, obj, msg, "distinguishedName");
	obj->object.identifier->dn = ldb_dn_get_linearized(obj_dn);
	obj->object.identifier->guid = samdb_result_guid(msg, "objectGUID");
	sid = samdb_result_dom_sid(obj, msg, "objectSid");
	if (sid) {
		dom_sid_split_rid(NULL, sid, NULL, &rid);
		obj->object.identifier->sid = *sid;
	} else {
		ZERO_STRUCT(obj->object.identifier->sid);
	}

	obj->object.flags = DRSUAPI_DS_REPLICA_OBJECT_FROM_MASTER;
	obj->object.attribute_ctr.num_attributes = obj->meta_data_ctr->count;
	obj->object.attribute_ctr.attributes = talloc_array(obj, struct drsuapi_DsReplicaAttribute,
							    obj->object.attribute_ctr.num_attributes);

	/*
	 * Note that the meta_data array and the attributes array must
	 * be the same size and in the same order
	 */
	for (i=0; i<obj->object.attribute_ctr.num_attributes; i++) {
		struct ldb_message_element *el;
		WERROR werr;
		const struct dsdb_attribute *sa;
	
		sa = dsdb_attribute_by_attributeID_id(schema, attids[i]);
		if (!sa) {
			DEBUG(0,("Unable to find attributeID %u in schema\n", attids[i]));
			return WERR_DS_DRA_INTERNAL_ERROR;
		}

		el = ldb_msg_find_element(msg, sa->lDAPDisplayName);
		if (el == NULL) {
			DEBUG(0,("No element '%s' for attributeID %u in message\n", 
				 sa->lDAPDisplayName, attids[i]));
			ZERO_STRUCT(obj->object.attribute_ctr.attributes[i]);
			obj->object.attribute_ctr.attributes[i].attid = attids[i];
		} else {
			werr = dsdb_attribute_ldb_to_drsuapi(sam_ctx, schema, el, obj,
							     &obj->object.attribute_ctr.attributes[i]);
			if (!W_ERROR_IS_OK(werr)) {
				DEBUG(0,("Unable to convert %s to DRS object - %s\n", 
					 sa->lDAPDisplayName, win_errstr(werr)));
				return werr;
			}
			/* if DRSUAPI_DRS_SPECIAL_SECRET_PROCESSING is set
			 * check if attribute is secret and send a null value
			 */
			if (replica_flags & DRSUAPI_DRS_SPECIAL_SECRET_PROCESSING) {
				drsuapi_process_secret_attribute(&obj->object.attribute_ctr.attributes[i],
								 &obj->meta_data_ctr->meta_data[i]);
			}
			/* some attributes needs to be encrypted
			   before being sent */
			werr = drsuapi_encrypt_attribute(obj, session_key, rid, 
							 &obj->object.attribute_ctr.attributes[i]);
			if (!W_ERROR_IS_OK(werr)) {
				DEBUG(0,("Unable to encrypt %s in DRS object - %s\n", 
					 sa->lDAPDisplayName, win_errstr(werr)));
				return werr;
			}
		}
	}

	return WERR_OK;
}

/*
  load replUpToDateVector from a DN
 */
static WERROR load_udv(struct ldb_context *sam_ctx, TALLOC_CTX *mem_ctx,
		       struct ldb_dn *dn, struct replUpToDateVectorBlob *ouv)
{
	const char *attrs[] = { "replUpToDateVector", NULL };
	struct ldb_result *res = NULL;
	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
	struct ldb_message_element *el;
	enum ndr_err_code ndr_err;

	ZERO_STRUCTP(ouv);

	if (ldb_search(sam_ctx, tmp_ctx, &res, dn, LDB_SCOPE_BASE, attrs, NULL) != LDB_SUCCESS ||
	    res->count < 1) {
		DEBUG(0,("load_udv: failed to read partition object\n"));
		talloc_free(tmp_ctx);
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	el = ldb_msg_find_element(res->msgs[0], "replUpToDateVector");
	if (el == NULL || el->num_values < 1) {
		talloc_free(tmp_ctx);
		ouv->version = 2;
		return WERR_OK;
	}

	ndr_err = ndr_pull_struct_blob(&el->values[0], 
				       mem_ctx, lp_iconv_convenience(ldb_get_opaque(sam_ctx, "loadparm")),
				       ouv, 
				       (ndr_pull_flags_fn_t)ndr_pull_replUpToDateVectorBlob);
	talloc_free(tmp_ctx);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		DEBUG(0,(__location__ ": Failed to parse replUpToDateVector for %s\n",
			 ldb_dn_get_linearized(dn)));
		return WERR_DS_DRA_INTERNAL_ERROR;
	}
	
	return WERR_OK;
	
}

/*
  fill in the cursors return based on the replUpToDateVector for the ncRoot_dn
 */
static WERROR get_nc_changes_udv(struct ldb_context *sam_ctx,
				 struct ldb_dn *ncRoot_dn,
				 struct drsuapi_DsReplicaCursor2CtrEx *udv)
{
	WERROR werr;
	struct drsuapi_DsReplicaCursor2 *tmp_cursor;
	uint64_t highest_commited_usn;
	NTTIME now;
	time_t t = time(NULL);
	int ret;
	struct replUpToDateVectorBlob ouv;

	werr = load_udv(sam_ctx, udv, ncRoot_dn, &ouv);
	if (!W_ERROR_IS_OK(werr)) {
		return werr;
	}
	
	ret = ldb_sequence_number(sam_ctx, LDB_SEQ_HIGHEST_SEQ, &highest_commited_usn);
	if (ret != LDB_SUCCESS) {
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	tmp_cursor = talloc(udv, struct drsuapi_DsReplicaCursor2);
	tmp_cursor->source_dsa_invocation_id = *(samdb_ntds_invocation_id(sam_ctx));
	tmp_cursor->highest_usn = highest_commited_usn;
	unix_to_nt_time(&now, t);
	tmp_cursor->last_sync_success = now;

	udv->count = ouv.ctr.ctr2.count + 1;
	udv->cursors = talloc_steal(udv, ouv.ctr.ctr2.cursors);
	udv->cursors = talloc_realloc(udv, udv->cursors, struct drsuapi_DsReplicaCursor2, udv->count);
	if (!udv->cursors) {
		return WERR_DS_DRA_INTERNAL_ERROR;
	}
	udv->cursors[udv->count - 1] = *tmp_cursor;
	
	qsort(udv->cursors, udv->count,
	      sizeof(struct drsuapi_DsReplicaCursor2),
	      (comparison_fn_t)drsuapi_DsReplicaCursor2_compare);

	return WERR_OK;
}

/* state of a partially completed getncchanges call */
struct drsuapi_getncchanges_state {
	struct ldb_result *site_res;
	uint32_t num_sent;
	struct ldb_dn *ncRoot_dn;
	uint32_t min_usn;
};

/* 
  drsuapi_DsGetNCChanges

  see MS-DRSR 4.1.10.5.2 for basic logic of this function
*/
WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx,
				     struct drsuapi_DsGetNCChanges *r)
{
	struct drsuapi_DsReplicaObjectIdentifier *ncRoot;
	int ret;
	int i;
	struct dsdb_schema *schema;
	struct drsuapi_DsReplicaOIDMapping_Ctr *ctr;
	struct drsuapi_DsReplicaObjectListItemEx **currentObject;
	NTSTATUS status;
	DATA_BLOB session_key;
	const char *attrs[] = { "*", "distinguishedName", NULL };
	WERROR werr;
	struct dcesrv_handle *h;
	struct drsuapi_bind_state *b_state;	
	struct drsuapi_getncchanges_state *getnc_state;
	struct drsuapi_DsGetNCChangesRequest8 *req8;
	uint32_t options;

	DCESRV_PULL_HANDLE_WERR(h, r->in.bind_handle, DRSUAPI_BIND_HANDLE);
	b_state = h->data;

	*r->out.level_out = 6;
	/* TODO: linked attributes*/
	r->out.ctr->ctr6.linked_attributes_count = 0;
	r->out.ctr->ctr6.linked_attributes = NULL;

	r->out.ctr->ctr6.object_count = 0;
	r->out.ctr->ctr6.nc_object_count = 0;
	r->out.ctr->ctr6.more_data = false;
	r->out.ctr->ctr6.uptodateness_vector = NULL;

	/* a RODC doesn't allow for any replication */
	if (samdb_rodc(ldb_get_opaque(b_state->sam_ctx, "loadparm"))) {
		DEBUG(0,(__location__ ": DsGetNCChanges attempt on RODC\n"));
		return WERR_DS_DRA_SOURCE_DISABLED;
	}

	/* Check request revision. 
	   TODO: Adding mappings to req8 from the other levels
	 */
	if (r->in.level != 8) {
		DEBUG(0,(__location__ ": Request for DsGetNCChanges with unsupported level %u\n",
			 r->in.level));
		return WERR_REVISION_MISMATCH;
	}

	req8 = &r->in.req->req8;

        /* Perform access checks. */
	ncRoot = req8->naming_context;
	if (ncRoot == NULL) {
		DEBUG(0,(__location__ ": Request for DsGetNCChanges with no NC\n"));
		return WERR_DS_DRA_INVALID_PARAMETER;
	}

	if (samdb_ntds_options(b_state->sam_ctx, &options) != LDB_SUCCESS) {
		return WERR_DS_DRA_INTERNAL_ERROR;
	}
	
	if ((options & DS_NTDSDSA_OPT_DISABLE_OUTBOUND_REPL) &&
	    !(req8->replica_flags & DRSUAPI_DRS_SYNC_FORCED)) {
		return WERR_DS_DRA_SOURCE_DISABLED;
	}


	if (req8->replica_flags & DRSUAPI_DS_REPLICA_NEIGHBOUR_FULL_SYNC_PACKET) {
		/* Ignore the _in_ uptpdateness vector*/
		req8->uptodateness_vector = NULL;
	} 

	werr = drs_security_level_check(dce_call, "DsGetNCChanges");
	if (!W_ERROR_IS_OK(werr)) {
		return werr;
	}

	getnc_state = b_state->getncchanges_state;
	if (getnc_state == NULL) {
		getnc_state = talloc_zero(b_state, struct drsuapi_getncchanges_state);
		if (getnc_state == NULL) {
			return WERR_NOMEM;
		}
		b_state->getncchanges_state = getnc_state;
	}

	/* we need the session key for encrypting password attributes */
	status = dcesrv_inherited_session_key(dce_call->conn, &session_key);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,(__location__ ": Failed to get session key\n"));
		return WERR_DS_DRA_INTERNAL_ERROR;		
	}

	/* we don't yet support extended operations */
	if (req8->extended_op != DRSUAPI_EXOP_NONE) {
		DEBUG(0,(__location__ ": Request for DsGetNCChanges extended op 0x%x\n",
			 (unsigned)req8->extended_op));
		return WERR_DS_DRA_NOT_SUPPORTED;
	}

	/* 
	   TODO: MS-DRSR section 4.1.10.1.1
	   Work out if this is the start of a new cycle */

	if (getnc_state->site_res == NULL) {
		char* search_filter;
		enum ldb_scope scope = LDB_SCOPE_SUBTREE;

		getnc_state->min_usn = req8->highwatermark.highest_usn;

		/* Construct response. */
		search_filter = talloc_asprintf(mem_ctx,
						"(uSNChanged>=%llu)",
						(unsigned long long)(getnc_state->min_usn+1));
	
		if (req8->replica_flags & DRSUAPI_DS_REPLICA_NEIGHBOUR_CRITICAL_ONLY) {
			search_filter = talloc_asprintf(mem_ctx,
							"(&%s(isCriticalSystemObject=TRUE))",
							search_filter);
		}
		
		getnc_state->ncRoot_dn = ldb_dn_new(getnc_state, b_state->sam_ctx, ncRoot->dn);
		if (req8->replica_flags & DRSUAPI_DS_REPLICA_NEIGHBOUR_ASYNC_REP) {
			scope = LDB_SCOPE_BASE;
		}
		
		DEBUG(6,(__location__ ": getncchanges on %s using filter %s\n",
			 ldb_dn_get_linearized(getnc_state->ncRoot_dn), search_filter));
		ret = drsuapi_search_with_extended_dn(b_state->sam_ctx, getnc_state, &getnc_state->site_res,
						      getnc_state->ncRoot_dn, scope, attrs,
						      "uSNChanged",
						      search_filter);
		if (ret != LDB_SUCCESS) {
			return WERR_DS_DRA_INTERNAL_ERROR;
		}
	} else {
		/* check that this request is for the same NC as the previous one */
		struct ldb_dn *dn;
		dn = ldb_dn_new(getnc_state, b_state->sam_ctx, ncRoot->dn);
		if (!dn) {
			return WERR_NOMEM;
		}
		if (ldb_dn_compare(dn, getnc_state->ncRoot_dn) != 0) {
			DEBUG(0,(__location__ ": DsGetNCChanges 2nd replication on different DN %s %s\n",
				 ldb_dn_get_linearized(dn),
				 ldb_dn_get_linearized(getnc_state->ncRoot_dn)));
			return WERR_DS_DRA_BAD_NC;
		}
	}

	/* Prefix mapping */
	schema = dsdb_get_schema(b_state->sam_ctx);
	if (!schema) {
		DEBUG(0,("No schema in sam_ctx\n"));
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	r->out.ctr->ctr6.naming_context = talloc(mem_ctx, struct drsuapi_DsReplicaObjectIdentifier);
	*r->out.ctr->ctr6.naming_context = *ncRoot;

	if (dsdb_find_guid_by_dn(b_state->sam_ctx, getnc_state->ncRoot_dn, 
				 &r->out.ctr->ctr6.naming_context->guid) != LDB_SUCCESS) {
		DEBUG(0,(__location__ ": Failed to find GUID of ncRoot_dn %s\n",
			 ldb_dn_get_linearized(getnc_state->ncRoot_dn)));
		return WERR_DS_DRA_INTERNAL_ERROR;
	}

	/* find the SID if there is one */
	dsdb_find_sid_by_dn(b_state->sam_ctx, getnc_state->ncRoot_dn, &r->out.ctr->ctr6.naming_context->sid);

	dsdb_get_oid_mappings_drsuapi(schema, true, mem_ctx, &ctr);
	r->out.ctr->ctr6.mapping_ctr = *ctr;

	r->out.ctr->ctr6.source_dsa_guid = *(samdb_ntds_objectGUID(b_state->sam_ctx));
	r->out.ctr->ctr6.source_dsa_invocation_id = *(samdb_ntds_invocation_id(b_state->sam_ctx));

	r->out.ctr->ctr6.old_highwatermark = req8->highwatermark;
	r->out.ctr->ctr6.new_highwatermark = req8->highwatermark;

	r->out.ctr->ctr6.first_object = NULL;
	currentObject = &r->out.ctr->ctr6.first_object;

	for(i=getnc_state->num_sent; 
	    i<getnc_state->site_res->count && 
		    (r->out.ctr->ctr6.object_count < req8->max_object_count);
	    i++) {
		int uSN;
		struct drsuapi_DsReplicaObjectListItemEx *obj;
		obj = talloc_zero(mem_ctx, struct drsuapi_DsReplicaObjectListItemEx);

		uSN = ldb_msg_find_attr_as_int(getnc_state->site_res->msgs[i], "uSNChanged", -1);
		if (uSN > r->out.ctr->ctr6.new_highwatermark.tmp_highest_usn) {
			r->out.ctr->ctr6.new_highwatermark.tmp_highest_usn = uSN;
		}

		werr = get_nc_changes_build_object(obj, getnc_state->site_res->msgs[i], 
						   b_state->sam_ctx, getnc_state->ncRoot_dn, 
						   schema, &session_key, getnc_state->min_usn,
						   req8->replica_flags);
		if (!W_ERROR_IS_OK(werr)) {
			return werr;
		}

		if (obj->meta_data_ctr == NULL) {
			DEBUG(0,(__location__ ": getncchanges skipping send of object %s\n",
				 ldb_dn_get_linearized(getnc_state->site_res->msgs[i]->dn)));
			/* no attributes to send */
			talloc_free(obj);
			continue;
		}

		r->out.ctr->ctr6.object_count++;
		
		*currentObject = obj;
		currentObject = &obj->next_object;
	}

	getnc_state->num_sent += r->out.ctr->ctr6.object_count;

	r->out.ctr->ctr6.nc_object_count = getnc_state->site_res->count;

	/* the client can us to call UpdateRefs on its behalf to
	   re-establish monitoring of the NC */
	if ((req8->replica_flags & DRSUAPI_DRS_ADD_REF) && 
	    !GUID_all_zero(&req8->destination_dsa_guid)) {
		struct drsuapi_DsReplicaUpdateRefsRequest1 ureq;
		ureq.naming_context = ncRoot;
		ureq.dest_dsa_dns_name = talloc_asprintf(mem_ctx, "%s._msdcs.%s",
							 GUID_string(mem_ctx, &req8->destination_dsa_guid),
							 lp_realm(dce_call->conn->dce_ctx->lp_ctx));
		if (!ureq.dest_dsa_dns_name) {
			return WERR_NOMEM;
		}
		ureq.dest_dsa_guid = req8->destination_dsa_guid;
		ureq.options = DRSUAPI_DS_REPLICA_UPDATE_ADD_REFERENCE |
			DRSUAPI_DS_REPLICA_UPDATE_ASYNCHRONOUS_OPERATION |
			DRSUAPI_DS_REPLICA_UPDATE_GETCHG_CHECK;
		werr = drsuapi_UpdateRefs(b_state, mem_ctx, &ureq);
		if (!W_ERROR_IS_OK(werr)) {
			DEBUG(0,(__location__ ": Failed UpdateRefs in DsGetNCChanges - %s\n",
				 win_errstr(werr)));
		}
	}

	if (i < getnc_state->site_res->count) {
		r->out.ctr->ctr6.more_data = true;
	} else {
		r->out.ctr->ctr6.uptodateness_vector = talloc(mem_ctx, struct drsuapi_DsReplicaCursor2CtrEx);
		r->out.ctr->ctr6.uptodateness_vector->version = 2;
		r->out.ctr->ctr6.uptodateness_vector->reserved1 = 0;
		r->out.ctr->ctr6.uptodateness_vector->reserved2 = 0;

		r->out.ctr->ctr6.new_highwatermark.highest_usn = r->out.ctr->ctr6.new_highwatermark.tmp_highest_usn;

		werr = get_nc_changes_udv(b_state->sam_ctx, getnc_state->ncRoot_dn, 
					  r->out.ctr->ctr6.uptodateness_vector);
		if (!W_ERROR_IS_OK(werr)) {
			return werr;
		}

		talloc_free(getnc_state);
		b_state->getncchanges_state = NULL;
	}

	DEBUG(2,("DsGetNCChanges with uSNChanged >= %llu flags 0x%08x on %s gave %u objects\n", 
		 (unsigned long long)(req8->highwatermark.highest_usn+1),
		 req8->replica_flags,
		 ncRoot->dn, r->out.ctr->ctr6.object_count));

	return WERR_OK;
}