Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2219 insertions, 0 deletions

diff --git a/source4/dns_server/dlz_bind9.c b/source4/dns_server/dlz_bind9.c
new file mode 100644
index 0000000..409e2f3
--- /dev/null
+++ b/source4/dns_server/dlz_bind9.c
@@ -0,0 +1,2219 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   bind9 dlz driver for Samba
+
+   Copyright (C) 2010 Andrew Tridgell
+
+   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 "talloc.h"
+#include "param/param.h"
+#include "lib/events/events.h"
+#include "dsdb/samdb/samdb.h"
+#include "dsdb/common/util.h"
+#include "auth/auth.h"
+#include "auth/session.h"
+#include "auth/gensec/gensec.h"
+#include "librpc/gen_ndr/security.h"
+#include "auth/credentials/credentials.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "gen_ndr/ndr_dnsp.h"
+#include "gen_ndr/server_id.h"
+#include "messaging/messaging.h"
+#include <popt.h>
+#include "lib/util/dlinklist.h"
+#include "dlz_minimal.h"
+#include "dnsserver_common.h"
+#include "lib/util/smb_strtox.h"
+#include "lib/util/access.h"
+
+#undef strcasecmp
+
+struct b9_options {
+	const char *url;
+	const char *debug;
+};
+
+struct b9_zone {
+	char *name;
+	struct b9_zone *prev, *next;
+};
+
+struct dlz_bind9_data {
+	struct b9_options options;
+	struct ldb_context *samdb;
+	struct tevent_context *ev_ctx;
+	struct loadparm_context *lp;
+	int *transaction_token;
+	uint32_t soa_serial;
+	struct b9_zone *zonelist;
+
+	/* Used for dynamic update */
+	struct smb_krb5_context *smb_krb5_ctx;
+	struct auth4_context *auth_context;
+	struct auth_session_info *session_info;
+	char *update_name;
+
+	/* helper functions from the dlz_dlopen driver */
+	log_t *log;
+	dns_sdlz_putrr_t *putrr;
+	dns_sdlz_putnamedrr_t *putnamedrr;
+	dns_dlz_writeablezone_t *writeable_zone;
+};
+
+static struct dlz_bind9_data *dlz_bind9_state = NULL;
+static int dlz_bind9_state_ref_count = 0;
+
+static const char *zone_prefixes[] = {
+	"CN=MicrosoftDNS,DC=DomainDnsZones",
+	"CN=MicrosoftDNS,DC=ForestDnsZones",
+	"CN=MicrosoftDNS,CN=System",
+	NULL
+};
+
+/*
+ * Get a printable string representation of an isc_result_t
+ */
+static const char *isc_result_str( const isc_result_t result) {
+	switch (result) {
+	case ISC_R_SUCCESS:
+		return "ISC_R_SUCCESS";
+	case ISC_R_NOMEMORY:
+		return "ISC_R_NOMEMORY";
+	case ISC_R_NOPERM:
+		return "ISC_R_NOPERM";
+	case ISC_R_NOSPACE:
+		return "ISC_R_NOSPACE";
+	case ISC_R_NOTFOUND:
+		return "ISC_R_NOTFOUND";
+	case ISC_R_FAILURE:
+		return "ISC_R_FAILURE";
+	case ISC_R_NOTIMPLEMENTED:
+		return "ISC_R_NOTIMPLEMENTED";
+	case ISC_R_NOMORE:
+		return "ISC_R_NOMORE";
+	case ISC_R_INVALIDFILE:
+		return "ISC_R_INVALIDFILE";
+	case ISC_R_UNEXPECTED:
+		return "ISC_R_UNEXPECTED";
+	case ISC_R_FILENOTFOUND:
+		return "ISC_R_FILENOTFOUND";
+	default:
+		return "UNKNOWN";
+	}
+}
+
+/*
+  return the version of the API
+ */
+_PUBLIC_ int dlz_version(unsigned int *flags)
+{
+	return DLZ_DLOPEN_VERSION;
+}
+
+/*
+   remember a helper function from the bind9 dlz_dlopen driver
+ */
+static void b9_add_helper(struct dlz_bind9_data *state, const char *helper_name, void *ptr)
+{
+	if (strcmp(helper_name, "log") == 0) {
+		state->log = ptr;
+	}
+	if (strcmp(helper_name, "putrr") == 0) {
+		state->putrr = ptr;
+	}
+	if (strcmp(helper_name, "putnamedrr") == 0) {
+		state->putnamedrr = ptr;
+	}
+	if (strcmp(helper_name, "writeable_zone") == 0) {
+		state->writeable_zone = ptr;
+	}
+}
+
+/*
+ * Add a trailing '.' if it's missing
+ */
+static const char *b9_format_fqdn(TALLOC_CTX *mem_ctx, const char *str)
+{
+	size_t len;
+	const char *tmp;
+
+	if (str == NULL || str[0] == '\0') {
+		return str;
+	}
+
+	len = strlen(str);
+	if (str[len-1] != '.') {
+		tmp = talloc_asprintf(mem_ctx, "%s.", str);
+	} else {
+		tmp = str;
+	}
+	return tmp;
+}
+
+/*
+ * Format a record for bind9.
+ *
+ * On failure/error returns false, OR sets *data to NULL.
+ * Callers should check for both!
+ */
+static bool b9_format(struct dlz_bind9_data *state,
+		      TALLOC_CTX *mem_ctx,
+		      struct dnsp_DnssrvRpcRecord *rec,
+		      const char **type, const char **data)
+{
+	uint32_t i;
+	char *tmp;
+	const char *fqdn;
+
+	switch (rec->wType) {
+	case DNS_TYPE_A:
+		*type = "a";
+		*data = rec->data.ipv4;
+		break;
+
+	case DNS_TYPE_AAAA:
+		*type = "aaaa";
+		*data = rec->data.ipv6;
+		break;
+
+	case DNS_TYPE_CNAME:
+		*type = "cname";
+		*data = b9_format_fqdn(mem_ctx, rec->data.cname);
+		break;
+
+	case DNS_TYPE_TXT:
+		*type = "txt";
+		tmp = talloc_asprintf(mem_ctx, "\"%s\"", rec->data.txt.str[0]);
+		for (i=1; i<rec->data.txt.count; i++) {
+			talloc_asprintf_addbuf(&tmp, " \"%s\"", rec->data.txt.str[i]);
+		}
+		*data = tmp;
+		break;
+
+	case DNS_TYPE_PTR:
+		*type = "ptr";
+		*data = b9_format_fqdn(mem_ctx, rec->data.ptr);
+		break;
+
+	case DNS_TYPE_SRV:
+		*type = "srv";
+		fqdn = b9_format_fqdn(mem_ctx, rec->data.srv.nameTarget);
+		if (fqdn == NULL) {
+			return false;
+		}
+		*data = talloc_asprintf(mem_ctx, "%u %u %u %s",
+					rec->data.srv.wPriority,
+					rec->data.srv.wWeight,
+					rec->data.srv.wPort,
+					fqdn);
+		break;
+
+	case DNS_TYPE_MX:
+		*type = "mx";
+		fqdn = b9_format_fqdn(mem_ctx, rec->data.mx.nameTarget);
+		if (fqdn == NULL) {
+			return false;
+		}
+		*data = talloc_asprintf(mem_ctx, "%u %s",
+					rec->data.mx.wPriority, fqdn);
+		break;
+
+	case DNS_TYPE_NS:
+		*type = "ns";
+		*data = b9_format_fqdn(mem_ctx, rec->data.ns);
+		break;
+
+	case DNS_TYPE_SOA: {
+		const char *mname;
+		*type = "soa";
+
+		/* we need to fake the authoritative nameserver to
+		 * point at ourselves. This is how AD DNS servers
+		 * force clients to send updates to the right local DC
+		 */
+		mname = talloc_asprintf(mem_ctx, "%s.%s.",
+					lpcfg_netbios_name(state->lp),
+					lpcfg_dnsdomain(state->lp));
+		if (mname == NULL) {
+			return false;
+		}
+		mname = strlower_talloc(mem_ctx, mname);
+		if (mname == NULL) {
+			return false;
+		}
+
+		fqdn = b9_format_fqdn(mem_ctx, rec->data.soa.rname);
+		if (fqdn == NULL) {
+			return false;
+		}
+
+		state->soa_serial = rec->data.soa.serial;
+
+		*data = talloc_asprintf(mem_ctx, "%s %s %u %u %u %u %u",
+					mname, fqdn,
+					rec->data.soa.serial,
+					rec->data.soa.refresh,
+					rec->data.soa.retry,
+					rec->data.soa.expire,
+					rec->data.soa.minimum);
+		break;
+	}
+
+	default:
+		state->log(ISC_LOG_ERROR, "samba_dlz b9_format: unhandled record type %u",
+			   rec->wType);
+		return false;
+	}
+
+	return true;
+}
+
+static const struct {
+	enum dns_record_type dns_type;
+	const char *typestr;
+	bool single_valued;
+} dns_typemap[] = {
+	{ DNS_TYPE_A,     "A"     , false},
+	{ DNS_TYPE_AAAA,  "AAAA"  , false},
+	{ DNS_TYPE_CNAME, "CNAME" , true},
+	{ DNS_TYPE_TXT,   "TXT"   , false},
+	{ DNS_TYPE_PTR,   "PTR"   , false},
+	{ DNS_TYPE_SRV,   "SRV"   , false},
+	{ DNS_TYPE_MX,    "MX"    , false},
+	{ DNS_TYPE_NS,    "NS"    , false},
+	{ DNS_TYPE_SOA,   "SOA"   , true},
+};
+
+
+/*
+  see if a DNS type is single valued
+ */
+static bool b9_single_valued(enum dns_record_type dns_type)
+{
+	int i;
+	for (i=0; i<ARRAY_SIZE(dns_typemap); i++) {
+		if (dns_typemap[i].dns_type == dns_type) {
+			return dns_typemap[i].single_valued;
+		}
+	}
+	return false;
+}
+
+/*
+  get a DNS_TYPE_* value from the corresponding string
+ */
+static bool b9_dns_type(const char *type, enum dns_record_type *dtype)
+{
+	int i;
+	for (i=0; i<ARRAY_SIZE(dns_typemap); i++) {
+		if (strcasecmp(dns_typemap[i].typestr, type) == 0) {
+			*dtype = dns_typemap[i].dns_type;
+			return true;
+		}
+	}
+	return false;
+}
+
+
+#define DNS_PARSE_STR(ret, str, sep, saveptr) do {	\
+	(ret) = strtok_r(str, sep, &saveptr); \
+	if ((ret) == NULL) return false; \
+	} while (0)
+
+#define DNS_PARSE_UINT(ret, str, sep, saveptr) do {  \
+	char *istr = strtok_r(str, sep, &saveptr); \
+	int error = 0;\
+	if ((istr) == NULL) return false; \
+	(ret) = smb_strtoul(istr, NULL, 10, &error, SMB_STR_STANDARD); \
+	if (error != 0) {\
+		return false;\
+	}\
+	} while (0)
+
+/*
+  parse a record from bind9
+ */
+static bool b9_parse(struct dlz_bind9_data *state,
+		     const char *rdatastr,
+		     struct dnsp_DnssrvRpcRecord *rec)
+{
+	char *full_name, *dclass, *type;
+	char *str, *tmp, *saveptr=NULL;
+	int i;
+
+	str = talloc_strdup(rec, rdatastr);
+	if (str == NULL) {
+		return false;
+	}
+
+	/* parse the SDLZ string form */
+	DNS_PARSE_STR(full_name, str, "\t", saveptr);
+	DNS_PARSE_UINT(rec->dwTtlSeconds, NULL, "\t", saveptr);
+	DNS_PARSE_STR(dclass, NULL, "\t", saveptr);
+	DNS_PARSE_STR(type, NULL, "\t", saveptr);
+
+	/* construct the record */
+	for (i=0; i<ARRAY_SIZE(dns_typemap); i++) {
+		if (strcasecmp(type, dns_typemap[i].typestr) == 0) {
+			rec->wType = dns_typemap[i].dns_type;
+			break;
+		}
+	}
+	if (i == ARRAY_SIZE(dns_typemap)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: unsupported record type '%s' for '%s'",
+			   type, full_name);
+		return false;
+	}
+
+	switch (rec->wType) {
+	case DNS_TYPE_A:
+		DNS_PARSE_STR(rec->data.ipv4, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_AAAA:
+		DNS_PARSE_STR(rec->data.ipv6, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_CNAME:
+		DNS_PARSE_STR(rec->data.cname, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_TXT:
+		rec->data.txt.count = 0;
+		rec->data.txt.str = talloc_array(rec, const char *, rec->data.txt.count);
+		tmp = strtok_r(NULL, "\t", &saveptr);
+		while (tmp) {
+			rec->data.txt.str = talloc_realloc(rec, rec->data.txt.str, const char *,
+							rec->data.txt.count+1);
+			if (tmp[0] == '"') {
+				/* Strip quotes */
+				rec->data.txt.str[rec->data.txt.count] = talloc_strndup(rec, &tmp[1], strlen(tmp)-2);
+			} else {
+				rec->data.txt.str[rec->data.txt.count] = talloc_strdup(rec, tmp);
+			}
+			rec->data.txt.count++;
+			tmp = strtok_r(NULL, " ", &saveptr);
+		}
+		break;
+
+	case DNS_TYPE_PTR:
+		DNS_PARSE_STR(rec->data.ptr, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_SRV:
+		DNS_PARSE_UINT(rec->data.srv.wPriority, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.srv.wWeight, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.srv.wPort, NULL, " ", saveptr);
+		DNS_PARSE_STR(rec->data.srv.nameTarget, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_MX:
+		DNS_PARSE_UINT(rec->data.mx.wPriority, NULL, " ", saveptr);
+		DNS_PARSE_STR(rec->data.mx.nameTarget, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_NS:
+		DNS_PARSE_STR(rec->data.ns, NULL, " ", saveptr);
+		break;
+
+	case DNS_TYPE_SOA:
+		DNS_PARSE_STR(rec->data.soa.mname, NULL, " ", saveptr);
+		DNS_PARSE_STR(rec->data.soa.rname, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.soa.serial, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.soa.refresh, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.soa.retry, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.soa.expire, NULL, " ", saveptr);
+		DNS_PARSE_UINT(rec->data.soa.minimum, NULL, " ", saveptr);
+		break;
+
+	default:
+		state->log(ISC_LOG_ERROR, "samba_dlz b9_parse: unhandled record type %u",
+			   rec->wType);
+		return false;
+	}
+
+	/* we should be at the end of the buffer now */
+	if (strtok_r(NULL, "\t ", &saveptr) != NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz b9_parse: unexpected data at end of string for '%s'",
+		           rdatastr);
+		return false;
+	}
+
+	return true;
+}
+
+/*
+  send a resource record to bind9
+ */
+static isc_result_t b9_putrr(struct dlz_bind9_data *state,
+			     void *handle, struct dnsp_DnssrvRpcRecord *rec,
+			     const char **types)
+{
+	isc_result_t result;
+	const char *type, *data;
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+
+	if (!b9_format(state, tmp_ctx, rec, &type, &data)) {
+		return ISC_R_FAILURE;
+	}
+
+	if (data == NULL) {
+		talloc_free(tmp_ctx);
+		return ISC_R_NOMEMORY;
+	}
+
+	if (types) {
+		int i;
+		for (i=0; types[i]; i++) {
+			if (strcmp(types[i], type) == 0) break;
+		}
+		if (types[i] == NULL) {
+			/* skip it */
+			return ISC_R_SUCCESS;
+		}
+	}
+
+	result = state->putrr(handle, type, rec->dwTtlSeconds, data);
+	if (result != ISC_R_SUCCESS) {
+		state->log(ISC_LOG_ERROR, "Failed to put rr");
+	}
+	talloc_free(tmp_ctx);
+	return result;
+}
+
+
+/*
+  send a named resource record to bind9
+ */
+static isc_result_t b9_putnamedrr(struct dlz_bind9_data *state,
+				  void *handle, const char *name,
+				  struct dnsp_DnssrvRpcRecord *rec)
+{
+	isc_result_t result;
+	const char *type, *data;
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+
+	if (!b9_format(state, tmp_ctx, rec, &type, &data)) {
+		return ISC_R_FAILURE;
+	}
+
+	if (data == NULL) {
+		talloc_free(tmp_ctx);
+		return ISC_R_NOMEMORY;
+	}
+
+	result = state->putnamedrr(handle, name, type, rec->dwTtlSeconds, data);
+	if (result != ISC_R_SUCCESS) {
+		state->log(ISC_LOG_ERROR, "Failed to put named rr '%s'", name);
+	}
+	talloc_free(tmp_ctx);
+	return result;
+}
+
+/*
+   parse options
+ */
+static isc_result_t parse_options(struct dlz_bind9_data *state,
+				  unsigned int argc, const char **argv,
+				  struct b9_options *options)
+{
+	int opt;
+	poptContext pc;
+	struct poptOption long_options[] = {
+		{ "url", 'H', POPT_ARG_STRING, &options->url, 0, "database URL", "URL" },
+		{ "debug", 'd', POPT_ARG_STRING, &options->debug, 0, "debug level", "DEBUG" },
+		{0}
+	};
+
+	pc = poptGetContext("dlz_bind9", argc, argv, long_options,
+			POPT_CONTEXT_KEEP_FIRST);
+	while ((opt = poptGetNextOpt(pc)) != -1) {
+		switch (opt) {
+		default:
+			state->log(ISC_LOG_ERROR, "dlz_bind9: Invalid option %s: %s",
+				   poptBadOption(pc, 0), poptStrerror(opt));
+			poptFreeContext(pc);
+			return ISC_R_FAILURE;
+		}
+	}
+
+	poptFreeContext(pc);
+	return ISC_R_SUCCESS;
+}
+
+
+/*
+ * Create session info from PAC
+ * This is called as auth_context->generate_session_info_pac()
+ */
+static NTSTATUS b9_generate_session_info_pac(struct auth4_context *auth_context,
+					     TALLOC_CTX *mem_ctx,
+					     struct smb_krb5_context *smb_krb5_context,
+					     DATA_BLOB *pac_blob,
+					     const char *principal_name,
+					     const struct tsocket_address *remote_addr,
+					     uint32_t session_info_flags,
+					     struct auth_session_info **session_info)
+{
+	NTSTATUS status;
+	struct auth_user_info_dc *user_info_dc;
+	TALLOC_CTX *tmp_ctx;
+
+	tmp_ctx = talloc_new(mem_ctx);
+	NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
+
+	status = kerberos_pac_blob_to_user_info_dc(tmp_ctx,
+						   *pac_blob,
+						   smb_krb5_context->krb5_context,
+						   &user_info_dc,
+						   NULL,
+						   NULL);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return status;
+	}
+
+	if (!(user_info_dc->info->user_flags & NETLOGON_GUEST)) {
+		session_info_flags |= AUTH_SESSION_INFO_AUTHENTICATED;
+	}
+
+	session_info_flags |= AUTH_SESSION_INFO_SIMPLE_PRIVILEGES;
+
+	status = auth_generate_session_info(mem_ctx, auth_context->lp_ctx, NULL, user_info_dc,
+					    session_info_flags, session_info);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(tmp_ctx);
+		return status;
+	}
+
+	talloc_free(tmp_ctx);
+	return status;
+}
+
+/* Callback for the DEBUG() system, to catch the remaining messages */
+static void b9_debug(void *private_ptr, int msg_level, const char *msg)
+{
+	static const int isc_log_map[] = {
+		ISC_LOG_CRITICAL, /* 0 */
+		ISC_LOG_ERROR,    /* 1 */
+		ISC_LOG_WARNING,   /* 2 */
+		ISC_LOG_NOTICE    /* 3 */
+	};
+	struct dlz_bind9_data *state = private_ptr;
+	int     isc_log_level;
+
+	if (msg_level >= ARRAY_SIZE(isc_log_map) || msg_level < 0) {
+		isc_log_level = ISC_LOG_INFO;
+	} else {
+		isc_log_level = isc_log_map[msg_level];
+	}
+	state->log(isc_log_level, "samba_dlz: %s", msg);
+}
+
+static int dlz_state_debug_unregister(struct dlz_bind9_data *state)
+{
+	/* Stop logging (to the bind9 logs) */
+	debug_set_callback(NULL, NULL);
+	return 0;
+}
+
+/*
+  called to initialise the driver
+ */
+_PUBLIC_ isc_result_t dlz_create(const char *dlzname,
+				 unsigned int argc, const char **argv,
+				 void **dbdata, ...)
+{
+	struct dlz_bind9_data *state;
+	const char *helper_name;
+	va_list ap;
+	isc_result_t result;
+	struct ldb_dn *dn;
+	NTSTATUS nt_status;
+	int ret;
+	char *errstring = NULL;
+
+	if (dlz_bind9_state != NULL) {
+		dlz_bind9_state->log(ISC_LOG_ERROR,
+				     "samba_dlz: dlz_create ignored, #refs=%d",
+				     dlz_bind9_state_ref_count);
+		*dbdata = dlz_bind9_state;
+		dlz_bind9_state_ref_count++;
+		return ISC_R_SUCCESS;
+	}
+
+	state = talloc_zero(NULL, struct dlz_bind9_data);
+	if (state == NULL) {
+		return ISC_R_NOMEMORY;
+	}
+
+	talloc_set_destructor(state, dlz_state_debug_unregister);
+
+	/* fill in the helper functions */
+	va_start(ap, dbdata);
+	while ((helper_name = va_arg(ap, const char *)) != NULL) {
+		b9_add_helper(state, helper_name, va_arg(ap, void*));
+	}
+	va_end(ap);
+
+	/* Do not install samba signal handlers */
+	fault_setup_disable();
+
+	/* Start logging (to the bind9 logs) */
+	debug_set_callback(state, b9_debug);
+
+	state->ev_ctx = s4_event_context_init(state);
+	if (state->ev_ctx == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto failed;
+	}
+
+	result = parse_options(state, argc, argv, &state->options);
+	if (result != ISC_R_SUCCESS) {
+		goto failed;
+	}
+
+	state->lp = loadparm_init_global(true);
+	if (state->lp == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto failed;
+	}
+
+	if (state->options.debug) {
+		lpcfg_do_global_parameter(state->lp, "log level", state->options.debug);
+	} else {
+		lpcfg_do_global_parameter(state->lp, "log level", "0");
+	}
+
+	if (smb_krb5_init_context(state, state->lp, &state->smb_krb5_ctx) != 0) {
+		result = ISC_R_NOMEMORY;
+		goto failed;
+	}
+
+	nt_status = gensec_init();
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		result = ISC_R_NOMEMORY;
+		goto failed;
+	}
+
+	state->auth_context = talloc_zero(state, struct auth4_context);
+	if (state->auth_context == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto failed;
+	}
+
+	if (state->options.url == NULL) {
+		state->options.url = talloc_asprintf(state,
+						     "%s/dns/sam.ldb",
+						     lpcfg_binddns_dir(state->lp));
+		if (state->options.url == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto failed;
+		}
+
+		if (!file_exist(state->options.url)) {
+			state->options.url = talloc_asprintf(state,
+							     "%s/dns/sam.ldb",
+							     lpcfg_private_dir(state->lp));
+			if (state->options.url == NULL) {
+				result = ISC_R_NOMEMORY;
+				goto failed;
+			}
+		}
+	}
+
+	ret = samdb_connect_url(state,
+				state->ev_ctx,
+				state->lp,
+				system_session(state->lp),
+				0,
+				state->options.url,
+				NULL,
+				&state->samdb,
+				&errstring);
+	if (ret != LDB_SUCCESS) {
+		state->log(ISC_LOG_ERROR,
+			   "samba_dlz: Failed to connect to %s: %s",
+			   errstring, ldb_strerror(ret));
+		result = ISC_R_FAILURE;
+		goto failed;
+	}
+
+	dn = ldb_get_default_basedn(state->samdb);
+	if (dn == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: Unable to get basedn for %s - %s",
+			   state->options.url, ldb_errstring(state->samdb));
+		result = ISC_R_FAILURE;
+		goto failed;
+	}
+
+	state->log(ISC_LOG_INFO, "samba_dlz: started for DN %s",
+		   ldb_dn_get_linearized(dn));
+
+	state->auth_context->event_ctx = state->ev_ctx;
+	state->auth_context->lp_ctx = state->lp;
+	state->auth_context->sam_ctx = state->samdb;
+	state->auth_context->generate_session_info_pac = b9_generate_session_info_pac;
+
+	*dbdata = state;
+	dlz_bind9_state = state;
+	dlz_bind9_state_ref_count++;
+
+	return ISC_R_SUCCESS;
+
+failed:
+	state->log(ISC_LOG_INFO,
+		   "samba_dlz: FAILED dlz_create call result=%d #refs=%d",
+		   result,
+		   dlz_bind9_state_ref_count);
+	talloc_free(state);
+	return result;
+}
+
+/*
+  shutdown the backend
+ */
+_PUBLIC_ void dlz_destroy(void *dbdata)
+{
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+
+	dlz_bind9_state_ref_count--;
+	if (dlz_bind9_state_ref_count == 0) {
+		state->log(ISC_LOG_INFO, "samba_dlz: shutting down");
+		talloc_unlink(state, state->samdb);
+		talloc_free(state);
+		dlz_bind9_state = NULL;
+	} else {
+		state->log(ISC_LOG_INFO,
+			   "samba_dlz: dlz_destroy called. %d refs remaining.",
+			   dlz_bind9_state_ref_count);
+	}
+}
+
+
+/*
+  return the base DN for a zone
+ */
+static isc_result_t b9_find_zone_dn(struct dlz_bind9_data *state, const char *zone_name,
+				    TALLOC_CTX *mem_ctx, struct ldb_dn **zone_dn)
+{
+	int ret;
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+	const char *attrs[] = { NULL };
+	int i;
+
+	for (i=0; zone_prefixes[i]; i++) {
+		const char *casefold;
+		struct ldb_dn *dn;
+		struct ldb_result *res;
+		struct ldb_val zone_name_val
+			= data_blob_string_const(zone_name);
+
+		dn = ldb_dn_copy(tmp_ctx, ldb_get_default_basedn(state->samdb));
+		if (dn == NULL) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		/*
+		 * This dance ensures that it is not possible to put
+		 * (eg) an extra DC=x, into the DNS name being
+		 * queried
+		 */
+
+		if (!ldb_dn_add_child_fmt(dn,
+					  "DC=X,%s",
+					  zone_prefixes[i])) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		ret = ldb_dn_set_component(dn,
+					   0,
+					   "DC",
+					   zone_name_val);
+		if (ret != LDB_SUCCESS) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		/*
+		 * Check if this is a plausibly valid DN early
+		 * (time spent here will be saved during the
+		 * search due to an internal cache)
+		 */
+		casefold = ldb_dn_get_casefold(dn);
+
+		if (casefold == NULL) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOTFOUND;
+		}
+
+		ret = ldb_search(state->samdb, tmp_ctx, &res, dn, LDB_SCOPE_BASE, attrs, "objectClass=dnsZone");
+		if (ret == LDB_SUCCESS) {
+			if (zone_dn != NULL) {
+				*zone_dn = talloc_steal(mem_ctx, dn);
+			}
+			talloc_free(tmp_ctx);
+			return ISC_R_SUCCESS;
+		}
+		talloc_free(dn);
+	}
+
+	talloc_free(tmp_ctx);
+	return ISC_R_NOTFOUND;
+}
+
+
+/*
+  return the DN for a name. The record does not need to exist, but the
+  zone must exist
+ */
+static isc_result_t b9_find_name_dn(struct dlz_bind9_data *state, const char *name,
+				    TALLOC_CTX *mem_ctx, struct ldb_dn **dn)
+{
+	const char *p;
+
+	/* work through the name piece by piece, until we find a zone */
+	for (p=name; p; ) {
+		isc_result_t result;
+		result = b9_find_zone_dn(state, p, mem_ctx, dn);
+		if (result == ISC_R_SUCCESS) {
+			const char *casefold;
+
+			/* we found a zone, now extend the DN to get
+			 * the full DN
+			 */
+			bool ret;
+			if (p == name) {
+				ret = ldb_dn_add_child_fmt(*dn, "DC=@");
+				if (ret == false) {
+					talloc_free(*dn);
+					return ISC_R_NOMEMORY;
+				}
+			} else {
+				struct ldb_val name_val
+					= data_blob_const(name,
+							  (int)(p-name)-1);
+
+				if (!ldb_dn_add_child_val(*dn,
+							  "DC",
+							  name_val)) {
+					talloc_free(*dn);
+					return ISC_R_NOMEMORY;
+				}
+			}
+
+			/*
+			 * Check if this is a plausibly valid DN early
+			 * (time spent here will be saved during the
+			 * search due to an internal cache)
+			 */
+			casefold = ldb_dn_get_casefold(*dn);
+
+			if (casefold == NULL) {
+				return ISC_R_NOTFOUND;
+			}
+
+			return ISC_R_SUCCESS;
+		}
+		p = strchr(p, '.');
+		if (p == NULL) {
+			break;
+		}
+		p++;
+	}
+	return ISC_R_NOTFOUND;
+}
+
+
+/*
+  see if we handle a given zone
+ */
+_PUBLIC_ isc_result_t dlz_findzonedb(void *dbdata, const char *name,
+				     dns_clientinfomethods_t *methods,
+				     dns_clientinfo_t *clientinfo)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	isc_result_t result = ISC_R_SUCCESS;
+
+	result = b9_find_zone_dn(state, name, NULL, NULL);
+	 DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		NULL,
+		name,
+		NULL);
+	return result;
+}
+
+
+/*
+  lookup one record
+ */
+static isc_result_t dlz_lookup_types(struct dlz_bind9_data *state,
+				     const char *zone, const char *name,
+				     dns_sdlzlookup_t *lookup,
+				     const char **types)
+{
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+	struct ldb_dn *dn;
+	WERROR werr = WERR_DNS_ERROR_NAME_DOES_NOT_EXIST;
+	struct dnsp_DnssrvRpcRecord *records = NULL;
+	uint16_t num_records = 0, i;
+	struct ldb_val zone_name_val
+		= data_blob_string_const(zone);
+	struct ldb_val name_val
+		= data_blob_string_const(name);
+
+	for (i=0; zone_prefixes[i]; i++) {
+		int ret;
+		const char *casefold;
+		dn = ldb_dn_copy(tmp_ctx, ldb_get_default_basedn(state->samdb));
+		if (dn == NULL) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		/*
+		 * This dance ensures that it is not possible to put
+		 * (eg) an extra DC=x, into the DNS name being
+		 * queried
+		 */
+
+		if (!ldb_dn_add_child_fmt(dn,
+					  "DC=X,DC=X,%s",
+					  zone_prefixes[i])) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		ret = ldb_dn_set_component(dn,
+					   1,
+					   "DC",
+					   zone_name_val);
+		if (ret != LDB_SUCCESS) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		ret = ldb_dn_set_component(dn,
+					   0,
+					   "DC",
+					   name_val);
+		if (ret != LDB_SUCCESS) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		/*
+		 * Check if this is a plausibly valid DN early
+		 * (time spent here will be saved during the
+		 * search due to an internal cache)
+		 */
+		casefold = ldb_dn_get_casefold(dn);
+
+		if (casefold == NULL) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOTFOUND;
+		}
+
+		werr = dns_common_wildcard_lookup(state->samdb, tmp_ctx, dn,
+					 &records, &num_records);
+		if (W_ERROR_IS_OK(werr)) {
+			break;
+		}
+	}
+	if (!W_ERROR_IS_OK(werr)) {
+		talloc_free(tmp_ctx);
+		return ISC_R_NOTFOUND;
+	}
+
+	for (i=0; i < num_records; i++) {
+		isc_result_t result;
+
+		result = b9_putrr(state, lookup, &records[i], types);
+		if (result != ISC_R_SUCCESS) {
+			talloc_free(tmp_ctx);
+			return result;
+		}
+	}
+
+	talloc_free(tmp_ctx);
+	return ISC_R_SUCCESS;
+}
+
+/*
+  lookup one record
+ */
+_PUBLIC_ isc_result_t dlz_lookup(const char *zone, const char *name,
+				 void *dbdata, dns_sdlzlookup_t *lookup,
+				 dns_clientinfomethods_t *methods,
+				 dns_clientinfo_t *clientinfo)
+{
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	isc_result_t result = ISC_R_SUCCESS;
+	struct timeval start = timeval_current();
+
+	result = dlz_lookup_types(state, zone, name, lookup, NULL);
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		zone,
+		name,
+		NULL);
+
+	return result;
+}
+
+
+/*
+  see if a zone transfer is allowed
+ */
+_PUBLIC_ isc_result_t dlz_allowzonexfr(void *dbdata, const char *name, const char *client)
+{
+	struct dlz_bind9_data *state = talloc_get_type(
+		dbdata, struct dlz_bind9_data);
+	isc_result_t ret;
+	const char **authorized_clients, **denied_clients;
+	const char *cname="";
+
+	/* check that the zone is known */
+	ret = b9_find_zone_dn(state, name, NULL, NULL);
+	if (ret != ISC_R_SUCCESS) {
+		return ret;
+	}
+
+	/* default is to deny all transfers */
+
+	authorized_clients = lpcfg_dns_zone_transfer_clients_allow(state->lp);
+	denied_clients = lpcfg_dns_zone_transfer_clients_deny(state->lp);
+
+	/* The logic of allow_access() when both allow and deny lists are given
+	 * does not match our expectation here: it would allow clients that are
+	 * neither allowed nor denied.
+	 * Here, we want to deny clients by default.
+	 * Using the allow_access() function is still useful as it takes care of
+	 * parsing IP addresses and subnets in a consistent way with other options
+	 * from smb.conf.
+	 *
+	 * We will then check the deny list first, then the allow list, so that
+	 * we accept only clients that are explicitly allowed AND not explicitly
+	 * denied.
+	 */
+	if ((authorized_clients == NULL) && (denied_clients == NULL)) {
+		/* No "allow" or "deny" lists given. Deny by default. */
+		return ISC_R_NOPERM;
+	}
+
+	if (denied_clients != NULL) {
+		bool ok = allow_access(denied_clients, NULL, cname, client);
+		if (!ok) {
+			/* client on deny list. Deny. */
+			return ISC_R_NOPERM;
+		}
+	}
+
+	if (authorized_clients != NULL) {
+		bool ok = allow_access(NULL, authorized_clients, cname, client);
+		if (ok) {
+			/*
+			 * client is not on deny list and is on allow list.
+			 * This is the only place we should return "allow".
+			 */
+			return ISC_R_SUCCESS;
+		}
+	}
+	/* We shouldn't get here, but deny by default. */
+	return ISC_R_NOPERM;
+}
+
+/*
+  perform a zone transfer
+ */
+_PUBLIC_ isc_result_t dlz_allnodes(const char *zone, void *dbdata,
+				   dns_sdlzallnodes_t *allnodes)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	const char *attrs[] = { "dnsRecord", NULL };
+	int ret = LDB_ERR_NO_SUCH_OBJECT;
+	size_t i, j;
+	struct ldb_dn *dn = NULL;
+	struct ldb_result *res;
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+	struct ldb_val zone_name_val = data_blob_string_const(zone);
+	isc_result_t result = ISC_R_SUCCESS;
+
+	for (i=0; zone_prefixes[i]; i++) {
+		const char *casefold;
+
+		dn = ldb_dn_copy(tmp_ctx, ldb_get_default_basedn(state->samdb));
+		if (dn == NULL) {
+			talloc_free(tmp_ctx);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+
+		/*
+		 * This dance ensures that it is not possible to put
+		 * (eg) an extra DC=x, into the DNS name being
+		 * queried
+		 */
+
+		if (!ldb_dn_add_child_fmt(dn,
+					  "DC=X,%s",
+					  zone_prefixes[i])) {
+			talloc_free(tmp_ctx);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+
+		ret = ldb_dn_set_component(dn,
+					   0,
+					   "DC",
+					   zone_name_val);
+		if (ret != LDB_SUCCESS) {
+			talloc_free(tmp_ctx);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+
+		/*
+		 * Check if this is a plausibly valid DN early
+		 * (time spent here will be saved during the
+		 * search due to an internal cache)
+		 */
+		casefold = ldb_dn_get_casefold(dn);
+
+		if (casefold == NULL) {
+			result = ISC_R_NOTFOUND;
+			goto exit;
+		}
+
+		ret = ldb_search(state->samdb, tmp_ctx, &res, dn, LDB_SCOPE_SUBTREE,
+				 attrs, "objectClass=dnsNode");
+		if (ret == LDB_SUCCESS) {
+			break;
+		}
+	}
+	if (ret != LDB_SUCCESS || dn == NULL) {
+		talloc_free(tmp_ctx);
+		result = ISC_R_NOTFOUND;
+		goto exit;
+	}
+
+	for (i=0; i<res->count; i++) {
+		struct ldb_message_element *el;
+		TALLOC_CTX *el_ctx = talloc_new(tmp_ctx);
+		const char *rdn, *name;
+		const struct ldb_val *v;
+		WERROR werr;
+		struct dnsp_DnssrvRpcRecord *recs = NULL;
+		uint16_t num_recs = 0;
+
+		el = ldb_msg_find_element(res->msgs[i], "dnsRecord");
+		if (el == NULL || el->num_values == 0) {
+			state->log(ISC_LOG_INFO, "failed to find dnsRecord for %s",
+				   ldb_dn_get_linearized(dn));
+			talloc_free(el_ctx);
+			continue;
+		}
+
+		v = ldb_dn_get_rdn_val(res->msgs[i]->dn);
+		if (v == NULL) {
+			state->log(ISC_LOG_INFO, "failed to find RDN for %s",
+				   ldb_dn_get_linearized(dn));
+			talloc_free(el_ctx);
+			continue;
+		}
+
+		rdn = talloc_strndup(el_ctx, (char *)v->data, v->length);
+		if (rdn == NULL) {
+			talloc_free(tmp_ctx);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+
+		if (strcmp(rdn, "@") == 0) {
+			name = zone;
+		} else {
+			name = talloc_asprintf(el_ctx, "%s.%s", rdn, zone);
+		}
+		name = b9_format_fqdn(el_ctx, name);
+		if (name == NULL) {
+			talloc_free(tmp_ctx);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+
+		werr = dns_common_extract(state->samdb, el, el_ctx, &recs, &num_recs);
+		if (!W_ERROR_IS_OK(werr)) {
+			state->log(ISC_LOG_ERROR, "samba_dlz: failed to parse dnsRecord for %s, %s",
+				   ldb_dn_get_linearized(dn), win_errstr(werr));
+			talloc_free(el_ctx);
+			continue;
+		}
+
+		for (j=0; j < num_recs; j++) {
+			isc_result_t rc;
+
+			rc = b9_putnamedrr(state, allnodes, name, &recs[j]);
+			if (rc != ISC_R_SUCCESS) {
+				continue;
+			}
+		}
+
+		talloc_free(el_ctx);
+	}
+
+	talloc_free(tmp_ctx);
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		zone,
+		NULL,
+		NULL);
+	return result;
+}
+
+
+/*
+  start a transaction
+ */
+_PUBLIC_ isc_result_t dlz_newversion(const char *zone, void *dbdata, void **versionp)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	isc_result_t result = ISC_R_SUCCESS;
+
+	state->log(ISC_LOG_INFO, "samba_dlz: starting transaction on zone %s", zone);
+
+	if (state->transaction_token != NULL) {
+		state->log(ISC_LOG_INFO, "samba_dlz: transaction already started for zone %s", zone);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	state->transaction_token = talloc_zero(state, int);
+	if (state->transaction_token == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto exit;
+	}
+
+	if (ldb_transaction_start(state->samdb) != LDB_SUCCESS) {
+		state->log(ISC_LOG_INFO, "samba_dlz: failed to start a transaction for zone %s", zone);
+		talloc_free(state->transaction_token);
+		state->transaction_token = NULL;
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	*versionp = (void *)state->transaction_token;
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		zone,
+		NULL,
+		NULL);
+	return result;
+}
+
+/*
+  end a transaction
+ */
+_PUBLIC_ void dlz_closeversion(const char *zone, isc_boolean_t commit,
+			       void *dbdata, void **versionp)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	const char *data = NULL;
+
+	data = commit ? "commit" : "cancel";
+
+	if (state->transaction_token != (int *)*versionp) {
+		state->log(ISC_LOG_INFO, "samba_dlz: transaction not started for zone %s", zone);
+		goto exit;
+	}
+
+	if (commit) {
+		if (ldb_transaction_commit(state->samdb) != LDB_SUCCESS) {
+			state->log(ISC_LOG_INFO, "samba_dlz: failed to commit a transaction for zone %s", zone);
+			goto exit;
+		}
+		state->log(ISC_LOG_INFO, "samba_dlz: committed transaction on zone %s", zone);
+	} else {
+		if (ldb_transaction_cancel(state->samdb) != LDB_SUCCESS) {
+			state->log(ISC_LOG_INFO, "samba_dlz: failed to cancel a transaction for zone %s", zone);
+			goto exit;
+		}
+		state->log(ISC_LOG_INFO, "samba_dlz: cancelling transaction on zone %s", zone);
+	}
+
+	talloc_free(state->transaction_token);
+	state->transaction_token = NULL;
+	*versionp = NULL;
+
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(ISC_R_SUCCESS),
+		&start,
+		zone,
+		NULL,
+		data);
+}
+
+
+/*
+  see if there is a SOA record for a zone
+ */
+static bool b9_has_soa(struct dlz_bind9_data *state, struct ldb_dn *dn, const char *zone)
+{
+	TALLOC_CTX *tmp_ctx = talloc_new(state);
+	WERROR werr;
+	struct dnsp_DnssrvRpcRecord *records = NULL;
+	uint16_t num_records = 0, i;
+	struct ldb_val zone_name_val
+		= data_blob_string_const(zone);
+
+	/*
+	 * This dance ensures that it is not possible to put
+	 * (eg) an extra DC=x, into the DNS name being
+	 * queried
+	 */
+
+	if (!ldb_dn_add_child_val(dn,
+				  "DC",
+				  zone_name_val)) {
+		talloc_free(tmp_ctx);
+		return false;
+	}
+
+	/*
+	 * The SOA record is always stored under DC=@,DC=zonename
+	 * This can probably be removed when dns_common_lookup makes a fallback
+	 * lookup on @ pseudo record
+	 */
+
+	if (!ldb_dn_add_child_fmt(dn,"DC=@")) {
+		talloc_free(tmp_ctx);
+		return false;
+	}
+
+	werr = dns_common_lookup(state->samdb, tmp_ctx, dn,
+				 &records, &num_records, NULL);
+	if (!W_ERROR_IS_OK(werr)) {
+		talloc_free(tmp_ctx);
+		return false;
+	}
+
+	for (i=0; i < num_records; i++) {
+		if (records[i].wType == DNS_TYPE_SOA) {
+			talloc_free(tmp_ctx);
+			return true;
+		}
+	}
+
+	talloc_free(tmp_ctx);
+	return false;
+}
+
+static bool b9_zone_add(struct dlz_bind9_data *state, const char *name)
+{
+	struct b9_zone *zone;
+
+	zone = talloc_zero(state, struct b9_zone);
+	if (zone == NULL) {
+		return false;
+	}
+
+	zone->name = talloc_strdup(zone, name);
+	if (zone->name == NULL) {
+		talloc_free(zone);
+		return false;
+	}
+
+	DLIST_ADD(state->zonelist, zone);
+	return true;
+}
+
+static bool b9_zone_exists(struct dlz_bind9_data *state, const char *name)
+{
+	struct b9_zone *zone = state->zonelist;
+	bool found = false;
+
+	while (zone != NULL) {
+		if (strcasecmp(name, zone->name) == 0) {
+			found = true;
+			break;
+		}
+		zone = zone->next;
+	}
+
+	return found;
+}
+
+
+/*
+  configure a writeable zone
+ */
+_PUBLIC_ isc_result_t dlz_configure(dns_view_t *view, dns_dlzdb_t *dlzdb,
+				    void *dbdata)
+{
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	TALLOC_CTX *tmp_ctx;
+	struct ldb_dn *dn;
+	int i;
+
+	state->log(ISC_LOG_INFO, "samba_dlz: starting configure");
+	if (state->writeable_zone == NULL) {
+		state->log(ISC_LOG_INFO, "samba_dlz: no writeable_zone method available");
+		return ISC_R_FAILURE;
+	}
+
+	tmp_ctx = talloc_new(state);
+
+	for (i=0; zone_prefixes[i]; i++) {
+		const char *attrs[] = { "name", NULL };
+		int j, ret;
+		struct ldb_result *res;
+
+		dn = ldb_dn_copy(tmp_ctx, ldb_get_default_basedn(state->samdb));
+		if (dn == NULL) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		if (!ldb_dn_add_child_fmt(dn, "%s", zone_prefixes[i])) {
+			talloc_free(tmp_ctx);
+			return ISC_R_NOMEMORY;
+		}
+
+		ret = ldb_search(state->samdb, tmp_ctx, &res, dn, LDB_SCOPE_SUBTREE,
+				 attrs, "objectClass=dnsZone");
+		if (ret != LDB_SUCCESS) {
+			continue;
+		}
+
+		for (j=0; j<res->count; j++) {
+			isc_result_t result;
+			const char *zone = ldb_msg_find_attr_as_string(res->msgs[j], "name", NULL);
+			struct ldb_dn *zone_dn;
+
+			if (zone == NULL) {
+				continue;
+			}
+			/* Ignore zones that are not handled in BIND */
+			if ((strcmp(zone, "RootDNSServers") == 0) ||
+			    (strcmp(zone, "..TrustAnchors") == 0)) {
+				continue;
+			}
+			zone_dn = ldb_dn_copy(tmp_ctx, dn);
+			if (zone_dn == NULL) {
+				talloc_free(tmp_ctx);
+				return ISC_R_NOMEMORY;
+			}
+
+			if (!b9_has_soa(state, zone_dn, zone)) {
+				continue;
+			}
+
+			if (b9_zone_exists(state, zone)) {
+				state->log(ISC_LOG_WARNING, "samba_dlz: Ignoring duplicate zone '%s' from '%s'",
+					   zone, ldb_dn_get_linearized(zone_dn));
+				continue;
+			}
+
+			if (!b9_zone_add(state, zone)) {
+				talloc_free(tmp_ctx);
+				return ISC_R_NOMEMORY;
+			}
+
+			result = state->writeable_zone(view, dlzdb, zone);
+			if (result != ISC_R_SUCCESS) {
+				state->log(ISC_LOG_ERROR, "samba_dlz: Failed to configure zone '%s'",
+					   zone);
+				talloc_free(tmp_ctx);
+				return result;
+			}
+			state->log(ISC_LOG_INFO, "samba_dlz: configured writeable zone '%s'", zone);
+		}
+	}
+
+	talloc_free(tmp_ctx);
+	return ISC_R_SUCCESS;
+}
+
+/*
+  authorize a zone update
+ */
+_PUBLIC_ isc_boolean_t dlz_ssumatch(const char *signer, const char *name, const char *tcpaddr,
+				    const char *type, const char *key, uint32_t keydatalen, uint8_t *keydata,
+				    void *dbdata)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	TALLOC_CTX *tmp_ctx;
+	DATA_BLOB ap_req;
+	struct cli_credentials *server_credentials;
+	char *keytab_name;
+	char *keytab_file = NULL;
+	int ret;
+	int ldb_ret;
+	NTSTATUS nt_status;
+	struct gensec_security *gensec_ctx;
+	struct auth_session_info *session_info;
+	struct ldb_dn *dn;
+	isc_result_t rc;
+	struct ldb_result *res;
+	const char * attrs[] = { NULL };
+	uint32_t access_mask;
+	struct gensec_settings *settings = NULL;
+	const struct gensec_security_ops **backends = NULL;
+	size_t idx = 0;
+	isc_boolean_t result = ISC_FALSE;
+	NTSTATUS status;
+	bool ok;
+
+	/* Remove cached credentials, if any */
+	if (state->session_info) {
+		talloc_free(state->session_info);
+		state->session_info = NULL;
+	}
+	if (state->update_name) {
+		talloc_free(state->update_name);
+		state->update_name = NULL;
+	}
+
+	tmp_ctx = talloc_new(state);
+	if (tmp_ctx == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: no memory");
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	ap_req = data_blob_const(keydata, keydatalen);
+	server_credentials = cli_credentials_init(tmp_ctx);
+	if (!server_credentials) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to init server credentials");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	status = cli_credentials_set_krb5_context(server_credentials,
+						  state->smb_krb5_ctx);
+	if (!NT_STATUS_IS_OK(status)) {
+		state->log(ISC_LOG_ERROR,
+			   "samba_dlz: failed to set krb5 context");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	ok = cli_credentials_set_conf(server_credentials, state->lp);
+	if (!ok) {
+		state->log(ISC_LOG_ERROR,
+			   "samba_dlz: failed to load smb.conf");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	keytab_file = talloc_asprintf(tmp_ctx,
+				      "%s/dns.keytab",
+				      lpcfg_binddns_dir(state->lp));
+	if (keytab_file == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: Out of memory!");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	if (!file_exist(keytab_file)) {
+		keytab_file = talloc_asprintf(tmp_ctx,
+					      "%s/dns.keytab",
+					      lpcfg_private_dir(state->lp));
+		if (keytab_file == NULL) {
+			state->log(ISC_LOG_ERROR, "samba_dlz: Out of memory!");
+			talloc_free(tmp_ctx);
+			result = ISC_FALSE;
+			goto exit;
+		}
+	}
+
+	keytab_name = talloc_asprintf(tmp_ctx, "FILE:%s", keytab_file);
+	if (keytab_name == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: Out of memory!");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	ret = cli_credentials_set_keytab_name(server_credentials, state->lp, keytab_name,
+						CRED_SPECIFIED);
+	if (ret != 0) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to obtain server credentials from %s",
+			   keytab_name);
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+	talloc_free(keytab_name);
+
+	settings = lpcfg_gensec_settings(tmp_ctx, state->lp);
+	if (settings == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: lpcfg_gensec_settings failed");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+	backends = talloc_zero_array(settings,
+				     const struct gensec_security_ops *, 3);
+	if (backends == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: talloc_zero_array gensec_security_ops failed");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+	settings->backends = backends;
+
+	gensec_init();
+
+	backends[idx++] = gensec_security_by_oid(NULL, GENSEC_OID_KERBEROS5);
+	backends[idx++] = gensec_security_by_oid(NULL, GENSEC_OID_SPNEGO);
+
+	nt_status = gensec_server_start(tmp_ctx, settings,
+					state->auth_context, &gensec_ctx);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to start gensec server");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	gensec_set_credentials(gensec_ctx, server_credentials);
+
+	nt_status = gensec_start_mech_by_oid(gensec_ctx, GENSEC_OID_SPNEGO);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to start spnego");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	/*
+	 * We only allow SPNEGO/KRB5 and make sure the backend
+	 * to is RPC/IPC free.
+	 *
+	 * See gensec_gssapi_update_internal() as
+	 * GENSEC_SERVER.
+	 *
+	 * It allows gensec_update() not to block.
+	 *
+	 * If that changes in future we need to use
+	 * gensec_update_send/recv here!
+	 */
+	nt_status = gensec_update(gensec_ctx, tmp_ctx, ap_req, &ap_req);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: spnego update failed");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	nt_status = gensec_session_info(gensec_ctx, tmp_ctx, &session_info);
+	if (!NT_STATUS_IS_OK(nt_status)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to create session info");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	/* Get the DN from name */
+	rc = b9_find_name_dn(state, name, tmp_ctx, &dn);
+	if (rc != ISC_R_SUCCESS) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to find name %s", name);
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	/* make sure the dn exists, or find parent dn in case new object is being added */
+	ldb_ret = ldb_search(state->samdb, tmp_ctx, &res, dn, LDB_SCOPE_BASE,
+				attrs, "objectClass=dnsNode");
+	if (ldb_ret == LDB_ERR_NO_SUCH_OBJECT) {
+		ldb_dn_remove_child_components(dn, 1);
+		access_mask = SEC_ADS_CREATE_CHILD;
+		talloc_free(res);
+	} else if (ldb_ret == LDB_SUCCESS) {
+		access_mask = SEC_STD_REQUIRED | SEC_ADS_SELF_WRITE;
+		talloc_free(res);
+	} else {
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	/* Do ACL check */
+	ldb_ret = dsdb_check_access_on_dn(state->samdb, tmp_ctx, dn,
+						session_info->security_token,
+						access_mask, NULL);
+	if (ldb_ret != LDB_SUCCESS) {
+		state->log(ISC_LOG_INFO,
+			"samba_dlz: disallowing update of signer=%s name=%s type=%s error=%s",
+			signer, name, type, ldb_strerror(ldb_ret));
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+
+	/* Cache session_info, so it can be used in the actual add/delete operation */
+	state->update_name = talloc_strdup(state, name);
+	if (state->update_name == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: memory allocation error");
+		talloc_free(tmp_ctx);
+		result = ISC_FALSE;
+		goto exit;
+	}
+	state->session_info = talloc_steal(state, session_info);
+
+	state->log(ISC_LOG_INFO, "samba_dlz: allowing update of signer=%s name=%s tcpaddr=%s type=%s key=%s",
+		   signer, name, tcpaddr, type, key);
+
+	talloc_free(tmp_ctx);
+	result = ISC_TRUE;
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		NULL,
+		name,
+		NULL);
+	return result;
+}
+
+
+/*
+  see if two dns records match
+ */
+static bool b9_record_match(struct dnsp_DnssrvRpcRecord *rec1,
+			    struct dnsp_DnssrvRpcRecord *rec2)
+{
+	if (rec1->wType != rec2->wType) {
+		return false;
+	}
+	/* see if this type is single valued */
+	if (b9_single_valued(rec1->wType)) {
+		return true;
+	}
+
+	return dns_record_match(rec1, rec2);
+}
+
+/*
+ * Update session_info on samdb using the cached credentials
+ */
+static bool b9_set_session_info(struct dlz_bind9_data *state, const char *name)
+{
+	int ret;
+
+	if (state->update_name == NULL || state->session_info == NULL) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: invalid credentials");
+		return false;
+	}
+
+	/* Do not use client credentials, if we're not updating the client specified name */
+	if (strcmp(state->update_name, name) != 0) {
+		return true;
+	}
+
+	ret = ldb_set_opaque(
+		state->samdb,
+		DSDB_SESSION_INFO,
+		state->session_info);
+	if (ret != LDB_SUCCESS) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: unable to set session info");
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Reset session_info on samdb as system session
+ */
+static void b9_reset_session_info(struct dlz_bind9_data *state)
+{
+	ldb_set_opaque(
+		state->samdb,
+		DSDB_SESSION_INFO,
+		system_session(state->lp));
+}
+
+/*
+  add or modify a rdataset
+ */
+_PUBLIC_ isc_result_t dlz_addrdataset(const char *name, const char *rdatastr, void *dbdata, void *version)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	struct dnsp_DnssrvRpcRecord *rec;
+	struct ldb_dn *dn;
+	isc_result_t result = ISC_R_SUCCESS;
+	bool tombstoned = false;
+	bool needs_add = false;
+	struct dnsp_DnssrvRpcRecord *recs = NULL;
+	uint16_t num_recs = 0;
+	uint16_t first = 0;
+	uint16_t i;
+	WERROR werr;
+
+	if (state->transaction_token != (void*)version) {
+		state->log(ISC_LOG_INFO, "samba_dlz: bad transaction version");
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	rec = talloc_zero(state, struct dnsp_DnssrvRpcRecord);
+	if (rec == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto exit;
+	}
+
+	rec->rank        = DNS_RANK_ZONE;
+
+	if (!b9_parse(state, rdatastr, rec)) {
+		state->log(ISC_LOG_INFO, "samba_dlz: failed to parse rdataset '%s'", rdatastr);
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	/* find the DN of the record */
+	result = b9_find_name_dn(state, name, rec, &dn);
+	if (result != ISC_R_SUCCESS) {
+		talloc_free(rec);
+		goto exit;
+	}
+
+	/* get any existing records */
+	werr = dns_common_lookup(state->samdb, rec, dn,
+				 &recs, &num_recs, &tombstoned);
+	if (W_ERROR_EQUAL(werr, WERR_DNS_ERROR_NAME_DOES_NOT_EXIST)) {
+		needs_add = true;
+		werr = WERR_OK;
+	}
+	if (!W_ERROR_IS_OK(werr)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to parse dnsRecord for %s, %s",
+			   ldb_dn_get_linearized(dn), win_errstr(werr));
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	if (tombstoned) {
+		/*
+		 * we need to keep the existing tombstone record
+		 * and ignore it
+		 */
+		first = num_recs;
+	}
+
+	/* there may be existing records. We need to see if this will
+	 * replace a record or add to it
+	 */
+	for (i=first; i < num_recs; i++) {
+		if (b9_record_match(rec, &recs[i])) {
+			break;
+		}
+	}
+	if (i == UINT16_MAX) {
+		state->log(ISC_LOG_ERROR,
+			   "samba_dlz: failed to find record to modify, and "
+			   "there are already %u dnsRecord values for %s",
+			   i, ldb_dn_get_linearized(dn));
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	if (i == num_recs) {
+		/* set dwTimeStamp before increasing num_recs */
+		if (dns_name_is_static(recs, num_recs)) {
+			rec->dwTimeStamp = 0;
+		} else {
+			rec->dwTimeStamp = unix_to_dns_timestamp(time(NULL));
+		}
+		/* adding space for a new value */
+		recs = talloc_realloc(rec, recs,
+				      struct dnsp_DnssrvRpcRecord,
+				      num_recs + 1);
+		if (recs == NULL) {
+			talloc_free(rec);
+			result = ISC_R_NOMEMORY;
+			goto exit;
+		}
+		num_recs++;
+	} else {
+		/*
+		 * We are updating a record. Depending on whether aging is
+		 * enabled, and how old the old timestamp is,
+		 * dns_common_replace() will work out whether to bump the
+		 * timestamp or not. But to do that, we need to tell it the
+		 * old timestamp.
+		 */
+		if (! dns_name_is_static(recs, num_recs)) {
+			rec->dwTimeStamp = recs[i].dwTimeStamp;
+		}
+	}
+
+	recs[i] = *rec;
+
+	if (!b9_set_session_info(state, name)) {
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	/* modify the record */
+	werr = dns_common_replace(state->samdb, rec, dn,
+				  needs_add,
+				  state->soa_serial,
+				  recs, num_recs);
+	b9_reset_session_info(state);
+	if (!W_ERROR_IS_OK(werr)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to %s %s - %s",
+			   needs_add ? "add" : "modify",
+			   ldb_dn_get_linearized(dn), win_errstr(werr));
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	state->log(ISC_LOG_INFO, "samba_dlz: added rdataset %s '%s'", name, rdatastr);
+
+	talloc_free(rec);
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		NULL,
+		name,
+		rdatastr);
+	return result;
+}
+
+/*
+  remove a rdataset
+ */
+_PUBLIC_ isc_result_t dlz_subrdataset(const char *name, const char *rdatastr, void *dbdata, void *version)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	struct dnsp_DnssrvRpcRecord *rec;
+	struct ldb_dn *dn;
+	isc_result_t result = ISC_R_SUCCESS;
+	struct dnsp_DnssrvRpcRecord *recs = NULL;
+	uint16_t num_recs = 0;
+	uint16_t i;
+	WERROR werr;
+
+	if (state->transaction_token != (void*)version) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: bad transaction version");
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	rec = talloc_zero(state, struct dnsp_DnssrvRpcRecord);
+	if (rec == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto exit;
+	}
+
+	if (!b9_parse(state, rdatastr, rec)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to parse rdataset '%s'", rdatastr);
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	/* find the DN of the record */
+	result = b9_find_name_dn(state, name, rec, &dn);
+	if (result != ISC_R_SUCCESS) {
+		talloc_free(rec);
+		goto exit;
+	}
+
+	/* get the existing records */
+	werr = dns_common_lookup(state->samdb, rec, dn,
+				 &recs, &num_recs, NULL);
+	if (!W_ERROR_IS_OK(werr)) {
+		talloc_free(rec);
+		result = ISC_R_NOTFOUND;
+		goto exit;
+	}
+
+	for (i=0; i < num_recs; i++) {
+		if (b9_record_match(rec, &recs[i])) {
+			recs[i] = (struct dnsp_DnssrvRpcRecord) {
+				.wType = DNS_TYPE_TOMBSTONE,
+			};
+			break;
+		}
+	}
+	if (i == num_recs) {
+		talloc_free(rec);
+		result = ISC_R_NOTFOUND;
+		goto exit;
+	}
+
+	if (!b9_set_session_info(state, name)) {
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	/* modify the record */
+	werr = dns_common_replace(state->samdb, rec, dn,
+				  false,/* needs_add */
+				  state->soa_serial,
+				  recs, num_recs);
+	b9_reset_session_info(state);
+	if (!W_ERROR_IS_OK(werr)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to modify %s - %s",
+			   ldb_dn_get_linearized(dn), win_errstr(werr));
+		talloc_free(rec);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	state->log(ISC_LOG_INFO, "samba_dlz: subtracted rdataset %s '%s'", name, rdatastr);
+
+	talloc_free(rec);
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		NULL,
+		name,
+		rdatastr);
+	return result;
+}
+
+
+/*
+  delete all records of the given type
+ */
+_PUBLIC_ isc_result_t dlz_delrdataset(const char *name, const char *type, void *dbdata, void *version)
+{
+	struct timeval start = timeval_current();
+	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
+	TALLOC_CTX *tmp_ctx;
+	struct ldb_dn *dn;
+	isc_result_t result = ISC_R_SUCCESS;
+	enum dns_record_type dns_type;
+	bool found = false;
+	struct dnsp_DnssrvRpcRecord *recs = NULL;
+	uint16_t num_recs = 0;
+	uint16_t ri = 0;
+	WERROR werr;
+
+	if (state->transaction_token != (void*)version) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: bad transaction version");
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	if (!b9_dns_type(type, &dns_type)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: bad dns type %s in delete", type);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	tmp_ctx = talloc_new(state);
+
+	/* find the DN of the record */
+	result = b9_find_name_dn(state, name, tmp_ctx, &dn);
+	if (result != ISC_R_SUCCESS) {
+		talloc_free(tmp_ctx);
+		goto exit;
+	}
+
+	/* get the existing records */
+	werr = dns_common_lookup(state->samdb, tmp_ctx, dn,
+				 &recs, &num_recs, NULL);
+	if (!W_ERROR_IS_OK(werr)) {
+		talloc_free(tmp_ctx);
+		result = ISC_R_NOTFOUND;
+		goto exit;
+	}
+
+	for (ri=0; ri < num_recs; ri++) {
+		if (dns_type != recs[ri].wType) {
+			continue;
+		}
+
+		found = true;
+		recs[ri] = (struct dnsp_DnssrvRpcRecord) {
+			.wType = DNS_TYPE_TOMBSTONE,
+		};
+	}
+
+	if (!found) {
+		talloc_free(tmp_ctx);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	if (!b9_set_session_info(state, name)) {
+		talloc_free(tmp_ctx);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	/* modify the record */
+	werr = dns_common_replace(state->samdb, tmp_ctx, dn,
+				  false,/* needs_add */
+				  state->soa_serial,
+				  recs, num_recs);
+	b9_reset_session_info(state);
+	if (!W_ERROR_IS_OK(werr)) {
+		state->log(ISC_LOG_ERROR, "samba_dlz: failed to modify %s - %s",
+			   ldb_dn_get_linearized(dn), win_errstr(werr));
+		talloc_free(tmp_ctx);
+		result = ISC_R_FAILURE;
+		goto exit;
+	}
+
+	state->log(ISC_LOG_INFO, "samba_dlz: deleted rdataset %s of type %s", name, type);
+
+	talloc_free(tmp_ctx);
+exit:
+	DNS_COMMON_LOG_OPERATION(
+		isc_result_str(result),
+		&start,
+		NULL,
+		name,
+		type);
+	return result;
+}