Adding upstream version 1:9.18.19.upstream/1%9.18.19upstream

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

1 files changed, 862 insertions, 0 deletions

diff --git a/bin/tests/system/dlzexternal/driver/driver.c b/bin/tests/system/dlzexternal/driver/driver.c
new file mode 100644
index 0000000..20edfd0
--- /dev/null
+++ b/bin/tests/system/dlzexternal/driver/driver.c
@@ -0,0 +1,862 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*
+ * This provides a very simple example of an external loadable DLZ
+ * driver, with update support.
+ */
+
+#include "driver.h"
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <isc/log.h>
+#include <isc/result.h>
+#include <isc/string.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+#include <dns/dlz_dlopen.h>
+#include <dns/types.h>
+
+/* aliases for exported symbols */
+
+dlz_dlopen_version_t dlz_version;
+dlz_dlopen_create_t dlz_create;
+dlz_dlopen_destroy_t dlz_destroy;
+dlz_dlopen_findzonedb_t dlz_findzonedb;
+dlz_dlopen_lookup_t dlz_lookup;
+dlz_dlopen_allowzonexfr_t dlz_allowzonexfr;
+dlz_dlopen_allnodes_t dlz_allnodes;
+dlz_dlopen_newversion_t dlz_newversion;
+dlz_dlopen_closeversion_t dlz_closeversion;
+dlz_dlopen_configure_t dlz_configure;
+dlz_dlopen_ssumatch_t dlz_ssumatch;
+dlz_dlopen_addrdataset_t dlz_addrdataset;
+dlz_dlopen_subrdataset_t dlz_subrdataset;
+dlz_dlopen_delrdataset_t dlz_delrdataset;
+
+#define CHECK(x)                             \
+	do {                                 \
+		result = (x);                \
+		if (result != ISC_R_SUCCESS) \
+			goto failure;        \
+	} while (0)
+
+#define loginfo(...)                                           \
+	({                                                     \
+		if ((state != NULL) && (state->log != NULL))   \
+			state->log(ISC_LOG_INFO, __VA_ARGS__); \
+	})
+#define logerr(...)                                             \
+	({                                                      \
+		if ((state != NULL) && (state->log != NULL))    \
+			state->log(ISC_LOG_ERROR, __VA_ARGS__); \
+	})
+
+/* For this simple example, use fixed sized strings */
+struct record {
+	char name[100];
+	char type[10];
+	char data[200];
+	dns_ttl_t ttl;
+};
+
+#define MAX_RECORDS 100
+
+typedef void
+log_t(int level, const char *fmt, ...);
+
+struct dlz_example_data {
+	char *zone_name;
+
+	/* An example driver doesn't need good memory management :-) */
+	struct record current[MAX_RECORDS];
+	struct record adds[MAX_RECORDS];
+	struct record deletes[MAX_RECORDS];
+
+	bool transaction_started;
+
+	/* 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 bool
+single_valued(const char *type) {
+	const char *single[] = { "soa", "cname", NULL };
+	int i;
+
+	for (i = 0; single[i]; i++) {
+		if (strcasecmp(single[i], type) == 0) {
+			return (true);
+		}
+	}
+	return (false);
+}
+
+/*
+ * Add a record to a list
+ */
+static isc_result_t
+add_name(struct dlz_example_data *state, struct record *list, const char *name,
+	 const char *type, dns_ttl_t ttl, const char *data) {
+	int i;
+	bool single = single_valued(type);
+	int first_empty = -1;
+
+	for (i = 0; i < MAX_RECORDS; i++) {
+		INSIST(list[i].name != NULL);
+		if (first_empty == -1 && strlen(list[i].name) == 0U) {
+			first_empty = i;
+		}
+		if (strcasecmp(list[i].name, name) != 0) {
+			continue;
+		}
+		if (strcasecmp(list[i].type, type) != 0) {
+			continue;
+		}
+		if (!single && strcasecmp(list[i].data, data) != 0) {
+			continue;
+		}
+		break;
+	}
+	if (i == MAX_RECORDS && first_empty != -1) {
+		i = first_empty;
+	}
+	if (i == MAX_RECORDS) {
+		logerr("dlz_example: out of record space");
+		return (ISC_R_FAILURE);
+	}
+
+	if (strlen(name) >= sizeof(list[i].name) ||
+	    strlen(type) >= sizeof(list[i].type) ||
+	    strlen(data) >= sizeof(list[i].data))
+	{
+		return (ISC_R_NOSPACE);
+	}
+
+	strncpy(list[i].name, name, sizeof(list[i].name) - 1);
+	list[i].name[sizeof(list[i].name) - 1] = '\0';
+
+	strncpy(list[i].type, type, sizeof(list[i].type) - 1);
+	list[i].type[sizeof(list[i].type) - 1] = '\0';
+
+	strncpy(list[i].data, data, sizeof(list[i].data) - 1);
+	list[i].data[sizeof(list[i].data) - 1] = '\0';
+
+	list[i].ttl = ttl;
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Delete a record from a list
+ */
+static isc_result_t
+del_name(struct dlz_example_data *state, struct record *list, const char *name,
+	 const char *type, dns_ttl_t ttl, const char *data) {
+	int i;
+
+	UNUSED(state);
+
+	for (i = 0; i < MAX_RECORDS; i++) {
+		if (strcasecmp(name, list[i].name) == 0 &&
+		    strcasecmp(type, list[i].type) == 0 &&
+		    strcasecmp(data, list[i].data) == 0 && ttl == list[i].ttl)
+		{
+			break;
+		}
+	}
+	if (i == MAX_RECORDS) {
+		return (ISC_R_NOTFOUND);
+	}
+	memset(&list[i], 0, sizeof(struct record));
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+fmt_address(isc_sockaddr_t *addr, char *buffer, size_t size) {
+	char addr_buf[INET6_ADDRSTRLEN];
+	const char *ret;
+	uint16_t port = 0;
+
+	switch (addr->type.sa.sa_family) {
+	case AF_INET:
+		port = ntohs(addr->type.sin.sin_port);
+		ret = inet_ntop(AF_INET, &addr->type.sin.sin_addr, addr_buf,
+				sizeof(addr_buf));
+		break;
+	case AF_INET6:
+		port = ntohs(addr->type.sin6.sin6_port);
+		ret = inet_ntop(AF_INET6, &addr->type.sin6.sin6_addr, addr_buf,
+				sizeof(addr_buf));
+		break;
+	default:
+		return (ISC_R_FAILURE);
+	}
+
+	if (ret == NULL) {
+		return (ISC_R_FAILURE);
+	}
+
+	snprintf(buffer, size, "%s#%u", addr_buf, port);
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Return the version of the API
+ */
+int
+dlz_version(unsigned int *flags) {
+	UNUSED(flags);
+	return (DLZ_DLOPEN_VERSION);
+}
+
+/*
+ * Remember a helper function from the bind9 dlz_dlopen driver
+ */
+static void
+b9_add_helper(struct dlz_example_data *state, const char *helper_name,
+	      void *ptr) {
+	if (strcmp(helper_name, "log") == 0) {
+		state->log = (log_t *)ptr;
+	}
+	if (strcmp(helper_name, "putrr") == 0) {
+		state->putrr = (dns_sdlz_putrr_t *)ptr;
+	}
+	if (strcmp(helper_name, "putnamedrr") == 0) {
+		state->putnamedrr = (dns_sdlz_putnamedrr_t *)ptr;
+	}
+	if (strcmp(helper_name, "writeable_zone") == 0) {
+		state->writeable_zone = (dns_dlz_writeablezone_t *)ptr;
+	}
+}
+
+/*
+ * Called to initialize the driver
+ */
+isc_result_t
+dlz_create(const char *dlzname, unsigned int argc, char *argv[], void **dbdata,
+	   ...) {
+	struct dlz_example_data *state;
+	const char *helper_name;
+	va_list ap;
+	char soa_data[sizeof("@ hostmaster.root 123 900 600 86400 3600")];
+	isc_result_t result;
+	size_t n;
+
+	UNUSED(dlzname);
+
+	state = calloc(1, sizeof(struct dlz_example_data));
+	if (state == NULL) {
+		return (ISC_R_NOMEMORY);
+	}
+
+	/* 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);
+
+	if (argc < 2 || argv[1][0] == '\0') {
+		logerr("dlz_example: please specify a zone name");
+		dlz_destroy(state);
+		return (ISC_R_FAILURE);
+	}
+
+	/* Ensure zone name is absolute */
+	state->zone_name = malloc(strlen(argv[1]) + 2);
+	if (state->zone_name == NULL) {
+		free(state);
+		return (ISC_R_NOMEMORY);
+	}
+	if (argv[1][strlen(argv[1]) - 1] == '.') {
+		strcpy(state->zone_name, argv[1]);
+	} else {
+		sprintf(state->zone_name, "%s.", argv[1]);
+	}
+
+	/*
+	 * Use relative names to trigger ISC_R_NOSPACE in dns_sdlz_putrr.
+	 */
+	if (strcmp(state->zone_name, ".") == 0) {
+		n = strlcpy(soa_data,
+			    "@ hostmaster.root 123 900 600 86400 3600",
+			    sizeof(soa_data));
+	} else {
+		n = strlcpy(soa_data, "@ hostmaster 123 900 600 86400 3600",
+			    sizeof(soa_data));
+	}
+
+	if (n >= sizeof(soa_data)) {
+		CHECK(ISC_R_NOSPACE);
+	}
+
+	add_name(state, &state->current[0], state->zone_name, "soa", 3600,
+		 soa_data);
+	add_name(state, &state->current[0], state->zone_name, "ns", 3600,
+		 state->zone_name);
+	add_name(state, &state->current[0], state->zone_name, "a", 1800,
+		 "10.53.0.1");
+
+	loginfo("dlz_example: started for zone %s", state->zone_name);
+
+	*dbdata = state;
+	return (ISC_R_SUCCESS);
+
+failure:
+	free(state);
+	return (result);
+}
+
+/*
+ * Shut down the backend
+ */
+void
+dlz_destroy(void *dbdata) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	loginfo("dlz_example: shutting down zone %s", state->zone_name);
+	free(state->zone_name);
+	free(state);
+}
+
+/*
+ * See if we handle a given zone
+ */
+isc_result_t
+dlz_findzonedb(void *dbdata, const char *name, dns_clientinfomethods_t *methods,
+	       dns_clientinfo_t *clientinfo) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+	isc_sockaddr_t *src;
+	char addrbuf[100];
+	char absolute[1024];
+
+	strcpy(addrbuf, "unknown");
+	if (methods != NULL && methods->sourceip != NULL &&
+	    methods->version - methods->age <= DNS_CLIENTINFOMETHODS_VERSION &&
+	    DNS_CLIENTINFOMETHODS_VERSION <= methods->version)
+	{
+		methods->sourceip(clientinfo, &src);
+		fmt_address(src, addrbuf, sizeof(addrbuf));
+	}
+
+	loginfo("dlz_example: dlz_findzonedb called with name '%s' "
+		"in zone DB '%s' from %s",
+		name, state->zone_name, addrbuf);
+
+	/*
+	 * Returning ISC_R_NOTFOUND will cause the query logic to
+	 * check the database for parent names, looking for zone cuts.
+	 *
+	 * Returning ISC_R_NOMORE prevents the query logic from doing
+	 * this; it will move onto the next database after a single query.
+	 */
+	if (strcasecmp(name, "test.example.com") == 0) {
+		return (ISC_R_NOMORE);
+	}
+
+	/*
+	 * For example.net, only return ISC_R_NOMORE when queried
+	 * from 10.53.0.1.
+	 */
+	if (strcasecmp(name, "test.example.net") == 0 &&
+	    strncmp(addrbuf, "10.53.0.1", 9) == 0)
+	{
+		return (ISC_R_NOMORE);
+	}
+
+	/*
+	 * For bigcname.domain, return success so it appears to be
+	 * the zone origin; this regression tests a bug in which
+	 * zone origin nodes could fail to return SERVFAIL to the client.
+	 */
+	if (strcasecmp(name, "bigcname.domain") == 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	/*
+	 * Return success if we have an exact match between the
+	 * zone name and the qname
+	 */
+	if (strcasecmp(state->zone_name, name) == 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	snprintf(absolute, sizeof(absolute), "%s.", name);
+	if (strcasecmp(state->zone_name, absolute) == 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	return (ISC_R_NOTFOUND);
+}
+
+/*
+ * Look up one record in the sample database.
+ *
+ * If the queryname is "source-addr", send back a TXT record containing
+ * the address of the client, to test the use of 'methods' and 'clientinfo'
+ *
+ * If the queryname is "too-long", send back a TXT record that's too long
+ * to process; this should result in a SERVFAIL when queried.
+ */
+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) {
+	isc_result_t result;
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+	bool found = false;
+	void *dbversion = NULL;
+	isc_sockaddr_t *src;
+	char full_name[256];
+	char buf[512];
+	static char last[256];
+	static int count = 0;
+	int i, size;
+
+	UNUSED(zone);
+
+	if (state->putrr == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+
+	if (strcmp(name, "@") == 0) {
+		size = snprintf(full_name, sizeof(full_name), "%s",
+				state->zone_name);
+	} else if (strcmp(state->zone_name, ".") == 0) {
+		size = snprintf(full_name, sizeof(full_name), "%s.", name);
+	} else {
+		size = snprintf(full_name, sizeof(full_name), "%s.%s", name,
+				state->zone_name);
+	}
+
+	if (size < 0 || (size_t)size >= sizeof(full_name) ||
+	    (size_t)size >= sizeof(last))
+	{
+		return (ISC_R_NOSPACE);
+	}
+
+	/*
+	 * For test purposes, log all calls to dlz_lookup()
+	 */
+	if (strcasecmp(full_name, last) == 0) {
+		count++;
+	} else {
+		count = 1;
+		memcpy(last, full_name, size + 1);
+	}
+	loginfo("lookup #%d for %s", count, full_name);
+
+	/*
+	 * If we need to know the database version (as set in
+	 * the 'newversion' dlz function) we can pick it up from the
+	 * clientinfo.
+	 *
+	 * This allows a lookup to query the correct version of the DNS
+	 * data, if the DLZ can differentiate between versions.
+	 *
+	 * For example, if a new database transaction is created by
+	 * 'newversion', the lookup should query within the same
+	 * transaction scope if it can.
+	 *
+	 * If the DLZ only operates on 'live' data, then version
+	 * wouldn't necessarily be needed.
+	 */
+	if (clientinfo != NULL && clientinfo->version >= 2) {
+		dbversion = clientinfo->dbversion;
+		if (dbversion != NULL && *(bool *)dbversion) {
+			loginfo("dlz_example: lookup against live transaction");
+		}
+	}
+
+	if (strcmp(name, "source-addr") == 0) {
+		char ecsbuf[DNS_ECS_FORMATSIZE] = "not supported";
+		strncpy(buf, "unknown", sizeof(buf));
+		if (methods != NULL && methods->sourceip != NULL &&
+		    (methods->version - methods->age <=
+		     DNS_CLIENTINFOMETHODS_VERSION) &&
+		    DNS_CLIENTINFOMETHODS_VERSION <= methods->version)
+		{
+			methods->sourceip(clientinfo, &src);
+			fmt_address(src, buf, sizeof(buf));
+		}
+		if (clientinfo != NULL && clientinfo->version >= 3) {
+			if (clientinfo->ecs.addr.family != AF_UNSPEC) {
+				dns_ecs_format(&clientinfo->ecs, ecsbuf,
+					       sizeof(ecsbuf));
+			} else {
+				snprintf(ecsbuf, sizeof(ecsbuf), "%s",
+					 "not present");
+			}
+		}
+		i = strlen(buf);
+		snprintf(buf + i, sizeof(buf) - i - 1, " ECS %s", ecsbuf);
+
+		loginfo("dlz_example: lookup connection from %s", buf);
+
+		found = true;
+		result = state->putrr(lookup, "TXT", 0, buf);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	if (strcmp(name, "too-long") == 0 ||
+	    strcmp(zone, "bigcname.domain") == 0)
+	{
+		for (i = 0; i < 511; i++) {
+			buf[i] = 'x';
+		}
+		buf[i] = '\0';
+		found = true;
+		result = state->putrr(lookup, "TXT", 0, buf);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	/* Tests for DLZ redirection zones */
+	if (strcmp(name, "*") == 0 && strcmp(zone, ".") == 0) {
+		result = state->putrr(lookup, "A", 0, "100.100.100.2");
+		found = true;
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	if (strcmp(name, "long.name.is.not.there") == 0 &&
+	    strcmp(zone, ".") == 0)
+	{
+		result = state->putrr(lookup, "A", 0, "100.100.100.3");
+		found = true;
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	/* Answer from current records */
+	for (i = 0; i < MAX_RECORDS; i++) {
+		if (strcasecmp(state->current[i].name, full_name) == 0) {
+			found = true;
+			result = state->putrr(lookup, state->current[i].type,
+					      state->current[i].ttl,
+					      state->current[i].data);
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+		}
+	}
+
+	if (!found) {
+		return (ISC_R_NOTFOUND);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * See if a zone transfer is allowed
+ */
+isc_result_t
+dlz_allowzonexfr(void *dbdata, const char *name, const char *client) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+	isc_result_t result;
+
+	loginfo("dlz_example: dlz_allowzonexfr called for %s", name);
+
+	result = dlz_findzonedb(dbdata, name, NULL, NULL);
+	if (result != ISC_R_SUCCESS) {
+		loginfo("dlz_example: findzonedb returned %s",
+			isc_result_totext(result));
+		return (result);
+	}
+
+	/*
+	 * Exception for "example.org" so we can test the use of
+	 * the view ACL.
+	 */
+	if (strcmp(name, "example.org") == 0) {
+		loginfo("dlz_example: use view ACL for example.org");
+		return (ISC_R_DEFAULT);
+	}
+
+	/*
+	 * Exception for 10.53.0.5 so we can test that allow-transfer
+	 * is effective.
+	 */
+	if (strcmp(client, "10.53.0.5") == 0) {
+		loginfo("dlz_example: disallow transfer to 10.53.0.5");
+		return (ISC_R_NOPERM);
+	}
+
+	loginfo("dlz_example: transfer allowed for %s", name);
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Perform a zone transfer
+ */
+isc_result_t
+dlz_allnodes(const char *zone, void *dbdata, dns_sdlzallnodes_t *allnodes) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+	int i;
+
+	UNUSED(zone);
+
+	if (state->putnamedrr == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+
+	for (i = 0; i < MAX_RECORDS; i++) {
+		isc_result_t result;
+		if (strlen(state->current[i].name) == 0U) {
+			continue;
+		}
+		result = state->putnamedrr(allnodes, state->current[i].name,
+					   state->current[i].type,
+					   state->current[i].ttl,
+					   state->current[i].data);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Start a transaction
+ */
+isc_result_t
+dlz_newversion(const char *zone, void *dbdata, void **versionp) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	if (state->transaction_started) {
+		loginfo("dlz_example: transaction already started for zone %s",
+			zone);
+		return (ISC_R_FAILURE);
+	}
+
+	state->transaction_started = true;
+	*versionp = (void *)&state->transaction_started;
+
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * End a transaction
+ */
+void
+dlz_closeversion(const char *zone, bool commit, void *dbdata, void **versionp) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	if (!state->transaction_started) {
+		loginfo("dlz_example: transaction not started for zone %s",
+			zone);
+		*versionp = NULL;
+		return;
+	}
+
+	state->transaction_started = false;
+
+	*versionp = NULL;
+
+	if (commit) {
+		int i;
+		loginfo("dlz_example: committing transaction on zone %s", zone);
+		for (i = 0; i < MAX_RECORDS; i++) {
+			if (strlen(state->deletes[i].name) > 0U) {
+				(void)del_name(state, &state->current[0],
+					       state->deletes[i].name,
+					       state->deletes[i].type,
+					       state->deletes[i].ttl,
+					       state->deletes[i].data);
+			}
+		}
+		for (i = 0; i < MAX_RECORDS; i++) {
+			if (strlen(state->adds[i].name) > 0U) {
+				(void)add_name(state, &state->current[0],
+					       state->adds[i].name,
+					       state->adds[i].type,
+					       state->adds[i].ttl,
+					       state->adds[i].data);
+			}
+		}
+	} else {
+		loginfo("dlz_example: cancelling transaction on zone %s", zone);
+	}
+	memset(state->adds, 0, sizeof(state->adds));
+	memset(state->deletes, 0, sizeof(state->deletes));
+}
+
+/*
+ * Configure a writeable zone
+ */
+isc_result_t
+dlz_configure(dns_view_t *view, dns_dlzdb_t *dlzdb, void *dbdata) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+	isc_result_t result;
+
+	loginfo("dlz_example: starting configure");
+
+	if (state->writeable_zone == NULL) {
+		loginfo("dlz_example: no writeable_zone method available");
+		return (ISC_R_FAILURE);
+	}
+
+	result = state->writeable_zone(view, dlzdb, state->zone_name);
+	if (result != ISC_R_SUCCESS) {
+		loginfo("dlz_example: failed to configure zone %s",
+			state->zone_name);
+		return (result);
+	}
+
+	loginfo("dlz_example: configured writeable zone %s", state->zone_name);
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * Authorize a zone update
+ */
+bool
+dlz_ssumatch(const char *signer, const char *name, const char *tcpaddr,
+	     const char *type, const char *key, uint32_t keydatalen,
+	     unsigned char *keydata, void *dbdata) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	UNUSED(tcpaddr);
+	UNUSED(type);
+	UNUSED(key);
+	UNUSED(keydatalen);
+	UNUSED(keydata);
+
+	if (strncmp(name, "deny.", 5) == 0) {
+		loginfo("dlz_example: denying update of name=%s by %s", name,
+			signer);
+		return (false);
+	}
+	loginfo("dlz_example: allowing update of name=%s by %s", name, signer);
+	return (true);
+}
+
+static isc_result_t
+modrdataset(struct dlz_example_data *state, const char *name,
+	    const char *rdatastr, struct record *list) {
+	char *full_name, *dclass, *type, *data, *ttlstr, *buf;
+	char absolute[1024];
+	isc_result_t result;
+	char *saveptr = NULL;
+
+	buf = strdup(rdatastr);
+	if (buf == NULL) {
+		return (ISC_R_FAILURE);
+	}
+
+	/*
+	 * The format is:
+	 * FULLNAME\tTTL\tDCLASS\tTYPE\tDATA
+	 *
+	 * The DATA field is space separated, and is in the data format
+	 * for the type used by dig
+	 */
+
+	full_name = strtok_r(buf, "\t", &saveptr);
+	if (full_name == NULL) {
+		goto error;
+	}
+
+	ttlstr = strtok_r(NULL, "\t", &saveptr);
+	if (ttlstr == NULL) {
+		goto error;
+	}
+
+	dclass = strtok_r(NULL, "\t", &saveptr);
+	if (dclass == NULL) {
+		goto error;
+	}
+
+	type = strtok_r(NULL, "\t", &saveptr);
+	if (type == NULL) {
+		goto error;
+	}
+
+	data = strtok_r(NULL, "\t", &saveptr);
+	if (data == NULL) {
+		goto error;
+	}
+
+	if (name[strlen(name) - 1] != '.') {
+		snprintf(absolute, sizeof(absolute), "%s.", name);
+		name = absolute;
+	}
+
+	result = add_name(state, list, name, type, strtoul(ttlstr, NULL, 10),
+			  data);
+	free(buf);
+	return (result);
+
+error:
+	free(buf);
+	return (ISC_R_FAILURE);
+}
+
+isc_result_t
+dlz_addrdataset(const char *name, const char *rdatastr, void *dbdata,
+		void *version) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	if (version != (void *)&state->transaction_started) {
+		return (ISC_R_FAILURE);
+	}
+
+	loginfo("dlz_example: adding rdataset %s '%s'", name, rdatastr);
+
+	return (modrdataset(state, name, rdatastr, &state->adds[0]));
+}
+
+isc_result_t
+dlz_subrdataset(const char *name, const char *rdatastr, void *dbdata,
+		void *version) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	if (version != (void *)&state->transaction_started) {
+		return (ISC_R_FAILURE);
+	}
+
+	loginfo("dlz_example: subtracting rdataset %s '%s'", name, rdatastr);
+
+	return (modrdataset(state, name, rdatastr, &state->deletes[0]));
+}
+
+isc_result_t
+dlz_delrdataset(const char *name, const char *type, void *dbdata,
+		void *version) {
+	struct dlz_example_data *state = (struct dlz_example_data *)dbdata;
+
+	if (version != (void *)&state->transaction_started) {
+		return (ISC_R_FAILURE);
+	}
+
+	loginfo("dlz_example: deleting rdataset %s of type %s", name, type);
+
+	return (ISC_R_SUCCESS);
+}