update.c

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/*
 * Copyright (C) 2011-2015  Internet Systems Consortium, Inc. ("ISC")
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>

#include <time.h>

#include <isc/log.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/netaddr.h>
#include <isc/print.h>
#include <isc/serial.h>
#include <isc/stats.h>
#include <isc/stdtime.h>
#include <isc/string.h>
#include <isc/taskpool.h>
#include <isc/time.h>
#include <isc/util.h>

#include <dns/db.h>
#include <dns/dbiterator.h>
#include <dns/diff.h>
#include <dns/dnssec.h>
#include <dns/events.h>
#include <dns/fixedname.h>
#include <dns/journal.h>
#include <dns/keyvalues.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/nsec.h>
#include <dns/nsec3.h>
#include <dns/private.h>
#include <dns/rdataclass.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/result.h>
#include <dns/soa.h>
#include <dns/ssu.h>
#include <dns/tsig.h>
#include <dns/update.h>
#include <dns/view.h>
#include <dns/zone.h>
#include <dns/zt.h>


/**************************************************************************/

#define STATE_MAGIC                     ISC_MAGIC('S', 'T', 'T', 'E')
#define DNS_STATE_VALID(state)          ISC_MAGIC_VALID(state, STATE_MAGIC)

/*%
 * Log level for tracing dynamic update protocol requests.
 */
#define LOGLEVEL_PROTOCOL       ISC_LOG_INFO

/*%
 * Log level for low-level debug tracing.
 */
#define LOGLEVEL_DEBUG          ISC_LOG_DEBUG(8)

/*%
 * Check an operation for failure.  These macros all assume that
 * the function using them has a 'result' variable and a 'failure'
 * label.
 */
#define CHECK(op) \
        do { result = (op); \
                if (result != ISC_R_SUCCESS) goto failure; \
        } while (0)

/*%
 * Fail unconditionally with result 'code', which must not
 * be ISC_R_SUCCESS.  The reason for failure presumably has
 * been logged already.
 *
 * The test against ISC_R_SUCCESS is there to keep the Solaris compiler
 * from complaining about "end-of-loop code not reached".
 */

#define FAIL(code) \
        do {                                                    \
                result = (code);                                \
                if (result != ISC_R_SUCCESS) goto failure;      \
        } while (0)

/*%
 * Fail unconditionally and log as a client error.
 * The test against ISC_R_SUCCESS is there to keep the Solaris compiler
 * from complaining about "end-of-loop code not reached".
 */
#define FAILC(code, msg) \
        do {                                                    \
                const char *_what = "failed";                   \
                result = (code);                                \
                switch (result) {                               \
                case DNS_R_NXDOMAIN:                            \
                case DNS_R_YXDOMAIN:                            \
                case DNS_R_YXRRSET:                             \
                case DNS_R_NXRRSET:                             \
                        _what = "unsuccessful";                 \
                }                                               \
                update_log(log, zone, LOGLEVEL_PROTOCOL,        \
                           "update %s: %s (%s)", _what,         \
                           msg, isc_result_totext(result));     \
                if (result != ISC_R_SUCCESS) goto failure;      \
        } while (0)

#define FAILN(code, name, msg) \
        do {                                                            \
                const char *_what = "failed";                           \
                result = (code);                                        \
                switch (result) {                                       \
                case DNS_R_NXDOMAIN:                                    \
                case DNS_R_YXDOMAIN:                                    \
                case DNS_R_YXRRSET:                                     \
                case DNS_R_NXRRSET:                                     \
                        _what = "unsuccessful";                         \
                }                                                       \
                if (isc_log_wouldlog(dns_lctx, LOGLEVEL_PROTOCOL)) {    \
                        char _nbuf[DNS_NAME_FORMATSIZE];                \
                        dns_name_format(name, _nbuf, sizeof(_nbuf));    \
                        update_log(log, zone, LOGLEVEL_PROTOCOL,        \
                                   "update %s: %s: %s (%s)", _what, _nbuf, \
                                   msg, isc_result_totext(result));     \
                }                                                       \
                if (result != ISC_R_SUCCESS) goto failure;              \
        } while (0)

#define FAILNT(code, name, type, msg) \
        do {                                                            \
                const char *_what = "failed";                           \
                result = (code);                                        \
                switch (result) {                                       \
                case DNS_R_NXDOMAIN:                                    \
                case DNS_R_YXDOMAIN:                                    \
                case DNS_R_YXRRSET:                                     \
                case DNS_R_NXRRSET:                                     \
                        _what = "unsuccessful";                         \
                }                                                       \
                if (isc_log_wouldlog(dns_lctx, LOGLEVEL_PROTOCOL)) {    \
                        char _nbuf[DNS_NAME_FORMATSIZE];                \
                        char _tbuf[DNS_RDATATYPE_FORMATSIZE];           \
                        dns_name_format(name, _nbuf, sizeof(_nbuf));    \
                        dns_rdatatype_format(type, _tbuf, sizeof(_tbuf)); \
                        update_log(log, zone, LOGLEVEL_PROTOCOL,        \
                                   "update %s: %s/%s: %s (%s)",         \
                                   _what, _nbuf, _tbuf, msg,            \
                                   isc_result_totext(result));          \
                }                                                       \
                if (result != ISC_R_SUCCESS) goto failure;              \
        } while (0)

/*%
 * Fail unconditionally and log as a server error.
 * The test against ISC_R_SUCCESS is there to keep the Solaris compiler
 * from complaining about "end-of-loop code not reached".
 */
#define FAILS(code, msg) \
        do {                                                    \
                result = (code);                                \
                update_log(log, zone, LOGLEVEL_PROTOCOL,        \
                           "error: %s: %s",                     \
                           msg, isc_result_totext(result));     \
                if (result != ISC_R_SUCCESS) goto failure;      \
        } while (0)

/**************************************************************************/

typedef struct rr rr_t;

struct rr {
        /* dns_name_t name; */
        isc_uint32_t            ttl;
        dns_rdata_t             rdata;
};

typedef struct update_event update_event_t;

/**************************************************************************/

static void
update_log(dns_update_log_t *callback, dns_zone_t *zone,
           int level, const char *fmt, ...) ISC_FORMAT_PRINTF(4, 5);

static void
update_log(dns_update_log_t *callback, dns_zone_t *zone,
           int level, const char *fmt, ...)
{
        va_list ap;
        char message[4096];

        if (callback == NULL)
                return;

        if (isc_log_wouldlog(dns_lctx, level) == ISC_FALSE)
                return;


        va_start(ap, fmt);
        vsnprintf(message, sizeof(message), fmt, ap);
        va_end(ap);

        (callback->func)(callback->arg, zone, level, message);
}

/*%
 * Update a single RR in version 'ver' of 'db' and log the
 * update in 'diff'.
 *
 * Ensures:
 * \li  '*tuple' == NULL.  Either the tuple is freed, or its
 *      ownership has been transferred to the diff.
 */
static isc_result_t
do_one_tuple(dns_difftuple_t **tuple, dns_db_t *db, dns_dbversion_t *ver,
             dns_diff_t *diff)
{
        dns_diff_t temp_diff;
        isc_result_t result;

        /*
         * Create a singleton diff.
         */
        dns_diff_init(diff->mctx, &temp_diff);
        ISC_LIST_APPEND(temp_diff.tuples, *tuple, link);

        /*
         * Apply it to the database.
         */
        result = dns_diff_apply(&temp_diff, db, ver);
        ISC_LIST_UNLINK(temp_diff.tuples, *tuple, link);
        if (result != ISC_R_SUCCESS) {
                dns_difftuple_free(tuple);
                return (result);
        }

        /*
         * Merge it into the current pending journal entry.
         */
        dns_diff_appendminimal(diff, tuple);

        /*
         * Do not clear temp_diff.
         */
        return (ISC_R_SUCCESS);
}

static isc_result_t
update_one_rr(dns_db_t *db, dns_dbversion_t *ver, dns_diff_t *diff,
              dns_diffop_t op, dns_name_t *name, dns_ttl_t ttl,
              dns_rdata_t *rdata)
{
        dns_difftuple_t *tuple = NULL;
        isc_result_t result;
        result = dns_difftuple_create(diff->mctx, op,
                                      name, ttl, rdata, &tuple);
        if (result != ISC_R_SUCCESS)
                return (result);
        return (do_one_tuple(&tuple, db, ver, diff));
}

/**************************************************************************/
/*
 * Callback-style iteration over rdatasets and rdatas.
 *
 * foreach_rrset() can be used to iterate over the RRsets
 * of a name and call a callback function with each
 * one.  Similarly, foreach_rr() can be used to iterate
 * over the individual RRs at name, optionally restricted
 * to RRs of a given type.
 *
 * The callback functions are called "actions" and take
 * two arguments: a void pointer for passing arbitrary
 * context information, and a pointer to the current RRset
 * or RR.  By convention, their names end in "_action".
 */

/*
 * XXXRTH  We might want to make this public somewhere in libdns.
 */

/*%
 * Function type for foreach_rrset() iterator actions.
 */
typedef isc_result_t rrset_func(void *data, dns_rdataset_t *rrset);

/*%
 * Function type for foreach_rr() iterator actions.
 */
typedef isc_result_t rr_func(void *data, rr_t *rr);

/*%
 * Internal context struct for foreach_node_rr().
 */
typedef struct {
        rr_func *       rr_action;
        void *          rr_action_data;
} foreach_node_rr_ctx_t;

/*%
 * Internal helper function for foreach_node_rr().
 */
static isc_result_t
foreach_node_rr_action(void *data, dns_rdataset_t *rdataset) {
        isc_result_t result;
        foreach_node_rr_ctx_t *ctx = data;
        for (result = dns_rdataset_first(rdataset);
             result == ISC_R_SUCCESS;
             result = dns_rdataset_next(rdataset))
        {
                rr_t rr = { 0, DNS_RDATA_INIT };

                dns_rdataset_current(rdataset, &rr.rdata);
                rr.ttl = rdataset->ttl;
                result = (*ctx->rr_action)(ctx->rr_action_data, &rr);
                if (result != ISC_R_SUCCESS)
                        return (result);
        }
        if (result != ISC_R_NOMORE)
                return (result);
        return (ISC_R_SUCCESS);
}

/*%
 * For each rdataset of 'name' in 'ver' of 'db', call 'action'
 * with the rdataset and 'action_data' as arguments.  If the name
 * does not exist, do nothing.
 *
 * If 'action' returns an error, abort iteration and return the error.
 */
static isc_result_t
foreach_rrset(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
              rrset_func *action, void *action_data)
{
        isc_result_t result;
        dns_dbnode_t *node;
        dns_rdatasetiter_t *iter;

        node = NULL;
        result = dns_db_findnode(db, name, ISC_FALSE, &node);
        if (result == ISC_R_NOTFOUND)
                return (ISC_R_SUCCESS);
        if (result != ISC_R_SUCCESS)
                return (result);

        iter = NULL;
        result = dns_db_allrdatasets(db, node, ver,
                                     (isc_stdtime_t) 0, &iter);
        if (result != ISC_R_SUCCESS)
                goto cleanup_node;

        for (result = dns_rdatasetiter_first(iter);
             result == ISC_R_SUCCESS;
             result = dns_rdatasetiter_next(iter))
        {
                dns_rdataset_t rdataset;

                dns_rdataset_init(&rdataset);
                dns_rdatasetiter_current(iter, &rdataset);

                result = (*action)(action_data, &rdataset);

                dns_rdataset_disassociate(&rdataset);
                if (result != ISC_R_SUCCESS)
                        goto cleanup_iterator;
        }
        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;

 cleanup_iterator:
        dns_rdatasetiter_destroy(&iter);

 cleanup_node:
        dns_db_detachnode(db, &node);

        return (result);
}

/*%
 * For each RR of 'name' in 'ver' of 'db', call 'action'
 * with the RR and 'action_data' as arguments.  If the name
 * does not exist, do nothing.
 *
 * If 'action' returns an error, abort iteration
 * and return the error.
 */
static isc_result_t
foreach_node_rr(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
                rr_func *rr_action, void *rr_action_data)
{
        foreach_node_rr_ctx_t ctx;
        ctx.rr_action = rr_action;
        ctx.rr_action_data = rr_action_data;
        return (foreach_rrset(db, ver, name,
                              foreach_node_rr_action, &ctx));
}


/*%
 * For each of the RRs specified by 'db', 'ver', 'name', 'type',
 * (which can be dns_rdatatype_any to match any type), and 'covers', call
 * 'action' with the RR and 'action_data' as arguments. If the name
 * does not exist, or if no RRset of the given type exists at the name,
 * do nothing.
 *
 * If 'action' returns an error, abort iteration and return the error.
 */
static isc_result_t
foreach_rr(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
           dns_rdatatype_t type, dns_rdatatype_t covers, rr_func *rr_action,
           void *rr_action_data)
{

        isc_result_t result;
        dns_dbnode_t *node;
        dns_rdataset_t rdataset;

        if (type == dns_rdatatype_any)
                return (foreach_node_rr(db, ver, name,
                                        rr_action, rr_action_data));

        node = NULL;
        if (type == dns_rdatatype_nsec3 ||
            (type == dns_rdatatype_rrsig && covers == dns_rdatatype_nsec3))
                result = dns_db_findnsec3node(db, name, ISC_FALSE, &node);
        else
                result = dns_db_findnode(db, name, ISC_FALSE, &node);
        if (result == ISC_R_NOTFOUND)
                return (ISC_R_SUCCESS);
        if (result != ISC_R_SUCCESS)
                return (result);

        dns_rdataset_init(&rdataset);
        result = dns_db_findrdataset(db, node, ver, type, covers,
                                     (isc_stdtime_t) 0, &rdataset, NULL);
        if (result == ISC_R_NOTFOUND) {
                result = ISC_R_SUCCESS;
                goto cleanup_node;
        }
        if (result != ISC_R_SUCCESS)
                goto cleanup_node;

        for (result = dns_rdataset_first(&rdataset);
             result == ISC_R_SUCCESS;
             result = dns_rdataset_next(&rdataset))
        {
                rr_t rr = { 0, DNS_RDATA_INIT };
                dns_rdataset_current(&rdataset, &rr.rdata);
                rr.ttl = rdataset.ttl;
                result = (*rr_action)(rr_action_data, &rr);
                if (result != ISC_R_SUCCESS)
                        goto cleanup_rdataset;
        }
        if (result != ISC_R_NOMORE)
                goto cleanup_rdataset;
        result = ISC_R_SUCCESS;

 cleanup_rdataset:
        dns_rdataset_disassociate(&rdataset);
 cleanup_node:
        dns_db_detachnode(db, &node);

        return (result);
}

/**************************************************************************/
/*
 * Various tests on the database contents (for prerequisites, etc).
 */

/*%
 * Function type for predicate functions that compare a database RR 'db_rr'
 * against an update RR 'update_rr'.
 */
typedef isc_boolean_t rr_predicate(dns_rdata_t *update_rr, dns_rdata_t *db_rr);

/*%
 * Helper function for rrset_exists().
 */
static isc_result_t
rrset_exists_action(void *data, rr_t *rr) {
        UNUSED(data);
        UNUSED(rr);
        return (ISC_R_EXISTS);
}

/*%
 * Utility macro for RR existence checking functions.
 *
 * If the variable 'result' has the value ISC_R_EXISTS or
 * ISC_R_SUCCESS, set *exists to ISC_TRUE or ISC_FALSE,
 * respectively, and return success.
 *
 * If 'result' has any other value, there was a failure.
 * Return the failure result code and do not set *exists.
 *
 * This would be more readable as "do { if ... } while(0)",
 * but that form generates tons of warnings on Solaris 2.6.
 */
#define RETURN_EXISTENCE_FLAG                           \
        return ((result == ISC_R_EXISTS) ?              \
                (*exists = ISC_TRUE, ISC_R_SUCCESS) :   \
                ((result == ISC_R_SUCCESS) ?            \
                 (*exists = ISC_FALSE, ISC_R_SUCCESS) : \
                 result))

/*%
 * Set '*exists' to true iff an rrset of the given type exists,
 * to false otherwise.
 */
static isc_result_t
rrset_exists(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
             dns_rdatatype_t type, dns_rdatatype_t covers,
             isc_boolean_t *exists)
{
        isc_result_t result;
        result = foreach_rr(db, ver, name, type, covers,
                            rrset_exists_action, NULL);
        RETURN_EXISTENCE_FLAG;
}

/*%
 * Set '*visible' to true if the RRset exists and is part of the
 * visible zone.  Otherwise '*visible' is set to false unless a
 * error occurs.
 */
static isc_result_t
rrset_visible(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
              dns_rdatatype_t type, isc_boolean_t *visible)
{
        isc_result_t result;
        dns_fixedname_t fixed;

        dns_fixedname_init(&fixed);
        result = dns_db_find(db, name, ver, type, DNS_DBFIND_NOWILD,
                             (isc_stdtime_t) 0, NULL,
                             dns_fixedname_name(&fixed), NULL, NULL);
        switch (result) {
        case ISC_R_SUCCESS:
                *visible = ISC_TRUE;
                break;
        /*
         * Glue, obscured, deleted or replaced records.
         */
        case DNS_R_DELEGATION:
        case DNS_R_DNAME:
        case DNS_R_CNAME:
        case DNS_R_NXDOMAIN:
        case DNS_R_NXRRSET:
        case DNS_R_EMPTYNAME:
        case DNS_R_COVERINGNSEC:
                *visible = ISC_FALSE;
                result = ISC_R_SUCCESS;
                break;
        default:
                break;
        }
        return (result);
}

/*%
 * Context struct and helper function for name_exists().
 */

static isc_result_t
name_exists_action(void *data, dns_rdataset_t *rrset) {
        UNUSED(data);
        UNUSED(rrset);
        return (ISC_R_EXISTS);
}

/*%
 * Set '*exists' to true iff the given name exists, to false otherwise.
 */
static isc_result_t
name_exists(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
            isc_boolean_t *exists)
{
        isc_result_t result;
        result = foreach_rrset(db, ver, name,
                               name_exists_action, NULL);
        RETURN_EXISTENCE_FLAG;
}

/**************************************************************************/
/*
 * Checking of "RRset exists (value dependent)" prerequisites.
 *
 * In the RFC2136 section 3.2.5, this is the pseudocode involving
 * a variable called "temp", a mapping of <name, type> tuples to rrsets.
 *
 * Here, we represent the "temp" data structure as (non-minimal) "dns_diff_t"
 * where each tuple has op==DNS_DIFFOP_EXISTS.
 */

/*%
 * A comparison function defining the sorting order for the entries
 * in the "temp" data structure.  The major sort key is the owner name,
 * followed by the type and rdata.
 */
static int
temp_order(const void *av, const void *bv) {
        dns_difftuple_t const * const *ap = av;
        dns_difftuple_t const * const *bp = bv;
        dns_difftuple_t const *a = *ap;
        dns_difftuple_t const *b = *bp;
        int r;
        r = dns_name_compare(&a->name, &b->name);
        if (r != 0)
                return (r);
        r = (b->rdata.type - a->rdata.type);
        if (r != 0)
                return (r);
        r = dns_rdata_casecompare(&a->rdata, &b->rdata);
        return (r);
}

/**************************************************************************/
/*
 * Conditional deletion of RRs.
 */

/*%
 * Context structure for delete_if().
 */

typedef struct {
        rr_predicate *predicate;
        dns_db_t *db;
        dns_dbversion_t *ver;
        dns_diff_t *diff;
        dns_name_t *name;
        dns_rdata_t *update_rr;
} conditional_delete_ctx_t;

/*%
 * Predicate functions for delete_if().
 */

/*%
 * Return true always.
 */
static isc_boolean_t
true_p(dns_rdata_t *update_rr, dns_rdata_t *db_rr) {
        UNUSED(update_rr);
        UNUSED(db_rr);
        return (ISC_TRUE);
}

/*%
 * Return true if the record is a RRSIG.
 */
static isc_boolean_t
rrsig_p(dns_rdata_t *update_rr, dns_rdata_t *db_rr) {
        UNUSED(update_rr);
        return ((db_rr->type == dns_rdatatype_rrsig) ?
                ISC_TRUE : ISC_FALSE);
}

/*%
 * Internal helper function for delete_if().
 */
static isc_result_t
delete_if_action(void *data, rr_t *rr) {
        conditional_delete_ctx_t *ctx = data;
        if ((*ctx->predicate)(ctx->update_rr, &rr->rdata)) {
                isc_result_t result;
                result = update_one_rr(ctx->db, ctx->ver, ctx->diff,
                                       DNS_DIFFOP_DEL, ctx->name,
                                       rr->ttl, &rr->rdata);
                return (result);
        } else {
                return (ISC_R_SUCCESS);
        }
}

/*%
 * Conditionally delete RRs.  Apply 'predicate' to the RRs
 * specified by 'db', 'ver', 'name', and 'type' (which can
 * be dns_rdatatype_any to match any type).  Delete those
 * RRs for which the predicate returns true, and log the
 * deletions in 'diff'.
 */
static isc_result_t
delete_if(rr_predicate *predicate, dns_db_t *db, dns_dbversion_t *ver,
          dns_name_t *name, dns_rdatatype_t type, dns_rdatatype_t covers,
          dns_rdata_t *update_rr, dns_diff_t *diff)
{
        conditional_delete_ctx_t ctx;
        ctx.predicate = predicate;
        ctx.db = db;
        ctx.ver = ver;
        ctx.diff = diff;
        ctx.name = name;
        ctx.update_rr = update_rr;
        return (foreach_rr(db, ver, name, type, covers,
                           delete_if_action, &ctx));
}

/**************************************************************************/
/*
 * Incremental updating of NSECs and RRSIGs.
 */

/*%
 * We abuse the dns_diff_t type to represent a set of domain names
 * affected by the update.
 */
static isc_result_t
namelist_append_name(dns_diff_t *list, dns_name_t *name) {
        isc_result_t result;
        dns_difftuple_t *tuple = NULL;
        static dns_rdata_t dummy_rdata = DNS_RDATA_INIT;

        CHECK(dns_difftuple_create(list->mctx, DNS_DIFFOP_EXISTS, name, 0,
                                   &dummy_rdata, &tuple));
        dns_diff_append(list, &tuple);
 failure:
        return (result);
}

static isc_result_t
namelist_append_subdomain(dns_db_t *db, dns_name_t *name, dns_diff_t *affected)
{
        isc_result_t result;
        dns_fixedname_t fixedname;
        dns_name_t *child;
        dns_dbiterator_t *dbit = NULL;

        dns_fixedname_init(&fixedname);
        child = dns_fixedname_name(&fixedname);

        CHECK(dns_db_createiterator(db, DNS_DB_NONSEC3, &dbit));

        for (result = dns_dbiterator_seek(dbit, name);
             result == ISC_R_SUCCESS;
             result = dns_dbiterator_next(dbit))
        {
                dns_dbnode_t *node = NULL;
                CHECK(dns_dbiterator_current(dbit, &node, child));
                dns_db_detachnode(db, &node);
                if (! dns_name_issubdomain(child, name))
                        break;
                CHECK(namelist_append_name(affected, child));
        }
        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;
 failure:
        if (dbit != NULL)
                dns_dbiterator_destroy(&dbit);
        return (result);
}



/*%
 * Helper function for non_nsec_rrset_exists().
 */
static isc_result_t
is_non_nsec_action(void *data, dns_rdataset_t *rrset) {
        UNUSED(data);
        if (!(rrset->type == dns_rdatatype_nsec ||
              rrset->type == dns_rdatatype_nsec3 ||
              (rrset->type == dns_rdatatype_rrsig &&
               (rrset->covers == dns_rdatatype_nsec ||
                rrset->covers == dns_rdatatype_nsec3))))
                return (ISC_R_EXISTS);
        return (ISC_R_SUCCESS);
}

/*%
 * Check whether there is an rrset other than a NSEC or RRSIG NSEC,
 * i.e., anything that justifies the continued existence of a name
 * after a secure update.
 *
 * If such an rrset exists, set '*exists' to ISC_TRUE.
 * Otherwise, set it to ISC_FALSE.
 */
static isc_result_t
non_nsec_rrset_exists(dns_db_t *db, dns_dbversion_t *ver,
                     dns_name_t *name, isc_boolean_t *exists)
{
        isc_result_t result;
        result = foreach_rrset(db, ver, name, is_non_nsec_action, NULL);
        RETURN_EXISTENCE_FLAG;
}

/*%
 * A comparison function for sorting dns_diff_t:s by name.
 */
static int
name_order(const void *av, const void *bv) {
        dns_difftuple_t const * const *ap = av;
        dns_difftuple_t const * const *bp = bv;
        dns_difftuple_t const *a = *ap;
        dns_difftuple_t const *b = *bp;
        return (dns_name_compare(&a->name, &b->name));
}

static isc_result_t
uniqify_name_list(dns_diff_t *list) {
        isc_result_t result;
        dns_difftuple_t *p, *q;

        CHECK(dns_diff_sort(list, name_order));

        p = ISC_LIST_HEAD(list->tuples);
        while (p != NULL) {
                do {
                        q = ISC_LIST_NEXT(p, link);
                        if (q == NULL || ! dns_name_equal(&p->name, &q->name))
                                break;
                        ISC_LIST_UNLINK(list->tuples, q, link);
                        dns_difftuple_free(&q);
                } while (1);
                p = ISC_LIST_NEXT(p, link);
        }
 failure:
        return (result);
}

static isc_result_t
is_active(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
          isc_boolean_t *flag, isc_boolean_t *cut, isc_boolean_t *unsecure)
{
        isc_result_t result;
        dns_fixedname_t foundname;
        dns_fixedname_init(&foundname);
        result = dns_db_find(db, name, ver, dns_rdatatype_any,
                             DNS_DBFIND_GLUEOK | DNS_DBFIND_NOWILD,
                             (isc_stdtime_t) 0, NULL,
                             dns_fixedname_name(&foundname),
                             NULL, NULL);
        if (result == ISC_R_SUCCESS || result == DNS_R_EMPTYNAME) {
                *flag = ISC_TRUE;
                *cut = ISC_FALSE;
                if (unsecure != NULL)
                        *unsecure = ISC_FALSE;
                return (ISC_R_SUCCESS);
        } else if (result == DNS_R_ZONECUT) {
                *flag = ISC_TRUE;
                *cut = ISC_TRUE;
                if (unsecure != NULL) {
                        /*
                         * We are at the zonecut.  Check to see if there
                         * is a DS RRset.
                         */
                        if (dns_db_find(db, name, ver, dns_rdatatype_ds, 0,
                                        (isc_stdtime_t) 0, NULL,
                                        dns_fixedname_name(&foundname),
                                        NULL, NULL) == DNS_R_NXRRSET)
                                *unsecure = ISC_TRUE;
                        else
                                *unsecure = ISC_FALSE;
                }
                return (ISC_R_SUCCESS);
        } else if (result == DNS_R_GLUE || result == DNS_R_DNAME ||
                   result == DNS_R_DELEGATION || result == DNS_R_NXDOMAIN) {
                *flag = ISC_FALSE;
                *cut = ISC_FALSE;
                if (unsecure != NULL)
                        *unsecure = ISC_FALSE;
                return (ISC_R_SUCCESS);
        } else {
                /*
                 * Silence compiler.
                 */
                *flag = ISC_FALSE;
                *cut = ISC_FALSE;
                if (unsecure != NULL)
                        *unsecure = ISC_FALSE;
                return (result);
        }
}

/*%
 * Find the next/previous name that has a NSEC record.
 * In other words, skip empty database nodes and names that
 * have had their NSECs removed because they are obscured by
 * a zone cut.
 */
static isc_result_t
next_active(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
            dns_dbversion_t *ver, dns_name_t *oldname, dns_name_t *newname,
            isc_boolean_t forward)
{
        isc_result_t result;
        dns_dbiterator_t *dbit = NULL;
        isc_boolean_t has_nsec = ISC_FALSE;
        unsigned int wraps = 0;
        isc_boolean_t secure = dns_db_issecure(db);

        CHECK(dns_db_createiterator(db, 0, &dbit));

        CHECK(dns_dbiterator_seek(dbit, oldname));
        do {
                dns_dbnode_t *node = NULL;

                if (forward)
                        result = dns_dbiterator_next(dbit);
                else
                        result = dns_dbiterator_prev(dbit);
                if (result == ISC_R_NOMORE) {
                        /*
                         * Wrap around.
                         */
                        if (forward)
                                CHECK(dns_dbiterator_first(dbit));
                        else
                                CHECK(dns_dbiterator_last(dbit));
                        wraps++;
                        if (wraps == 2) {
                                update_log(log, zone, ISC_LOG_ERROR,
                                           "secure zone with no NSECs");
                                result = DNS_R_BADZONE;
                                goto failure;
                        }
                }
                CHECK(dns_dbiterator_current(dbit, &node, newname));
                dns_db_detachnode(db, &node);

                /*
                 * The iterator may hold the tree lock, and
                 * rrset_exists() calls dns_db_findnode() which
                 * may try to reacquire it.  To avoid deadlock
                 * we must pause the iterator first.
                 */
                CHECK(dns_dbiterator_pause(dbit));
                if (secure) {
                        CHECK(rrset_exists(db, ver, newname,
                                           dns_rdatatype_nsec, 0, &has_nsec));
                } else {
                        dns_fixedname_t ffound;
                        dns_name_t *found;
                        dns_fixedname_init(&ffound);
                        found = dns_fixedname_name(&ffound);
                        result = dns_db_find(db, newname, ver,
                                             dns_rdatatype_soa,
                                             DNS_DBFIND_NOWILD, 0, NULL, found,
                                             NULL, NULL);
                        if (result == ISC_R_SUCCESS ||
                            result == DNS_R_EMPTYNAME ||
                            result == DNS_R_NXRRSET ||
                            result == DNS_R_CNAME ||
                            (result == DNS_R_DELEGATION &&
                             dns_name_equal(newname, found))) {
                                has_nsec = ISC_TRUE;
                                result = ISC_R_SUCCESS;
                        } else if (result != DNS_R_NXDOMAIN)
                                break;
                }
        } while (! has_nsec);
 failure:
        if (dbit != NULL)
                dns_dbiterator_destroy(&dbit);

        return (result);
}

/*%
 * Add a NSEC record for "name", recording the change in "diff".
 * The existing NSEC is removed.
 */
static isc_result_t
add_nsec(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
         dns_dbversion_t *ver, dns_name_t *name, dns_ttl_t nsecttl,
         dns_diff_t *diff)
{
        isc_result_t result;
        dns_dbnode_t *node = NULL;
        unsigned char buffer[DNS_NSEC_BUFFERSIZE];
        dns_rdata_t rdata = DNS_RDATA_INIT;
        dns_difftuple_t *tuple = NULL;
        dns_fixedname_t fixedname;
        dns_name_t *target;

        dns_fixedname_init(&fixedname);
        target = dns_fixedname_name(&fixedname);

        /*
         * Find the successor name, aka NSEC target.
         */
        CHECK(next_active(log, zone, db, ver, name, target, ISC_TRUE));

        /*
         * Create the NSEC RDATA.
         */
        CHECK(dns_db_findnode(db, name, ISC_FALSE, &node));
        dns_rdata_init(&rdata);
        CHECK(dns_nsec_buildrdata(db, ver, node, target, buffer, &rdata));
        dns_db_detachnode(db, &node);

        /*
         * Delete the old NSEC and record the change.
         */
        CHECK(delete_if(true_p, db, ver, name, dns_rdatatype_nsec, 0,
                        NULL, diff));
        /*
         * Add the new NSEC and record the change.
         */
        CHECK(dns_difftuple_create(diff->mctx, DNS_DIFFOP_ADD, name,
                                   nsecttl, &rdata, &tuple));
        CHECK(do_one_tuple(&tuple, db, ver, diff));
        INSIST(tuple == NULL);

 failure:
        if (node != NULL)
                dns_db_detachnode(db, &node);
        return (result);
}

/*%
 * Add a placeholder NSEC record for "name", recording the change in "diff".
 */
static isc_result_t
add_placeholder_nsec(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
                     dns_diff_t *diff)
{
        isc_result_t result;
        dns_difftuple_t *tuple = NULL;
        isc_region_t r;
        unsigned char data[1] = { 0 }; /* The root domain, no bits. */
        dns_rdata_t rdata = DNS_RDATA_INIT;

        r.base = data;
        r.length = sizeof(data);
        dns_rdata_fromregion(&rdata, dns_db_class(db), dns_rdatatype_nsec, &r);
        CHECK(dns_difftuple_create(diff->mctx, DNS_DIFFOP_ADD, name, 0,
                                   &rdata, &tuple));
        CHECK(do_one_tuple(&tuple, db, ver, diff));
 failure:
        return (result);
}

static isc_result_t
find_zone_keys(dns_zone_t *zone, dns_db_t *db, dns_dbversion_t *ver,
               isc_mem_t *mctx, unsigned int maxkeys,
               dst_key_t **keys, unsigned int *nkeys)
{
        isc_result_t result;
        dns_dbnode_t *node = NULL;
        const char *directory = dns_zone_getkeydirectory(zone);
        CHECK(dns_db_findnode(db, dns_db_origin(db), ISC_FALSE, &node));
        CHECK(dns_dnssec_findzonekeys2(db, ver, node, dns_db_origin(db),
                                       directory, mctx, maxkeys, keys, nkeys));
 failure:
        if (node != NULL)
                dns_db_detachnode(db, &node);
        return (result);
}

/*%
 * Add RRSIG records for an RRset, recording the change in "diff".
 */
static isc_result_t
add_sigs(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
         dns_dbversion_t *ver, dns_name_t *name, dns_rdatatype_t type,
         dns_diff_t *diff, dst_key_t **keys, unsigned int nkeys,
         isc_stdtime_t inception, isc_stdtime_t expire,
         isc_boolean_t check_ksk, isc_boolean_t keyset_kskonly)
{
        isc_result_t result;
        dns_dbnode_t *node = NULL;
        dns_rdataset_t rdataset;
        dns_rdata_t sig_rdata = DNS_RDATA_INIT;
        isc_buffer_t buffer;
        unsigned char data[1024]; /* XXX */
        unsigned int i, j;
        isc_boolean_t added_sig = ISC_FALSE;
        isc_mem_t *mctx = diff->mctx;

        dns_rdataset_init(&rdataset);
        isc_buffer_init(&buffer, data, sizeof(data));

        /* Get the rdataset to sign. */
        if (type == dns_rdatatype_nsec3)
                CHECK(dns_db_findnsec3node(db, name, ISC_FALSE, &node));
        else
                CHECK(dns_db_findnode(db, name, ISC_FALSE, &node));
        CHECK(dns_db_findrdataset(db, node, ver, type, 0,
                                  (isc_stdtime_t) 0, &rdataset, NULL));
        dns_db_detachnode(db, &node);

#define REVOKE(x) ((dst_key_flags(x) & DNS_KEYFLAG_REVOKE) != 0)
#define KSK(x) ((dst_key_flags(x) & DNS_KEYFLAG_KSK) != 0)
#define ALG(x) dst_key_alg(x)

        /*
         * If we are honoring KSK flags then we need to check that we
         * have both KSK and non-KSK keys that are not revoked per
         * algorithm.
         */
        for (i = 0; i < nkeys; i++) {
                isc_boolean_t both = ISC_FALSE;

                if (!dst_key_isprivate(keys[i]))
                        continue;

                if (check_ksk && !REVOKE(keys[i])) {
                        isc_boolean_t have_ksk, have_nonksk;
                        if (KSK(keys[i])) {
                                have_ksk = ISC_TRUE;
                                have_nonksk = ISC_FALSE;
                        } else {
                                have_ksk = ISC_FALSE;
                                have_nonksk = ISC_TRUE;
                        }
                        for (j = 0; j < nkeys; j++) {
                                if (j == i || ALG(keys[i]) != ALG(keys[j]))
                                        continue;
                                if (REVOKE(keys[j]))
                                        continue;
                                if (KSK(keys[j]))
                                        have_ksk = ISC_TRUE;
                                else
                                        have_nonksk = ISC_TRUE;
                                both = have_ksk && have_nonksk;
                                if (both)
                                        break;
                        }
                }

                if (both) {
                        if (type == dns_rdatatype_dnskey) {
                                if (!KSK(keys[i]) && keyset_kskonly)
                                        continue;
                        } else if (KSK(keys[i]))
                                continue;
                } else if (REVOKE(keys[i]) && type != dns_rdatatype_dnskey)
                        continue;

                /* Calculate the signature, creating a RRSIG RDATA. */
                CHECK(dns_dnssec_sign(name, &rdataset, keys[i],
                                      &inception, &expire,
                                      mctx, &buffer, &sig_rdata));

                /* Update the database and journal with the RRSIG. */
                /* XXX inefficient - will cause dataset merging */
                CHECK(update_one_rr(db, ver, diff, DNS_DIFFOP_ADDRESIGN, name,
                                    rdataset.ttl, &sig_rdata));
                dns_rdata_reset(&sig_rdata);
                isc_buffer_init(&buffer, data, sizeof(data));
                added_sig = ISC_TRUE;
        }
        if (!added_sig) {
                update_log(log, zone, ISC_LOG_ERROR,
                           "found no active private keys, "
                           "unable to generate any signatures");
                result = ISC_R_NOTFOUND;
        }

 failure:
        if (dns_rdataset_isassociated(&rdataset))
                dns_rdataset_disassociate(&rdataset);
        if (node != NULL)
                dns_db_detachnode(db, &node);
        return (result);
}

/*
 * Delete expired RRsigs and any RRsigs we are about to re-sign.
 * See also zone.c:del_sigs().
 */
static isc_result_t
del_keysigs(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
            dns_diff_t *diff, dst_key_t **keys, unsigned int nkeys)
{
        isc_result_t result;
        dns_dbnode_t *node = NULL;
        dns_rdataset_t rdataset;
        dns_rdata_t rdata = DNS_RDATA_INIT;
        unsigned int i;
        dns_rdata_rrsig_t rrsig;
        isc_boolean_t found;

        dns_rdataset_init(&rdataset);

        result = dns_db_findnode(db, name, ISC_FALSE, &node);
        if (result == ISC_R_NOTFOUND)
                return (ISC_R_SUCCESS);
        if (result != ISC_R_SUCCESS)
                goto failure;
        result = dns_db_findrdataset(db, node, ver, dns_rdatatype_rrsig,
                                     dns_rdatatype_dnskey, (isc_stdtime_t) 0,
                                     &rdataset, NULL);
        dns_db_detachnode(db, &node);

        if (result == ISC_R_NOTFOUND)
                return (ISC_R_SUCCESS);
        if (result != ISC_R_SUCCESS)
                goto failure;

        for (result = dns_rdataset_first(&rdataset);
             result == ISC_R_SUCCESS;
             result = dns_rdataset_next(&rdataset)) {
                dns_rdataset_current(&rdataset, &rdata);
                result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
                RUNTIME_CHECK(result == ISC_R_SUCCESS);
                found = ISC_FALSE;
                for (i = 0; i < nkeys; i++) {
                        if (rrsig.keyid == dst_key_id(keys[i])) {
                                found = ISC_TRUE;
                                if (!dst_key_isprivate(keys[i]) &&
                                    !dst_key_inactive(keys[i]))
                                {
                                        /*
                                         * The re-signing code in zone.c
                                         * will mark this as offline.
                                         * Just skip the record for now.
                                         */
                                        break;
                                }
                                result = update_one_rr(db, ver, diff,
                                                       DNS_DIFFOP_DEL, name,
                                                       rdataset.ttl, &rdata);
                                break;
                        }
                }
                /*
                 * If there is not a matching DNSKEY then delete the RRSIG.
                 */
                if (!found)
                        result = update_one_rr(db, ver, diff, DNS_DIFFOP_DEL,
                                               name, rdataset.ttl, &rdata);
                dns_rdata_reset(&rdata);
                if (result != ISC_R_SUCCESS)
                        break;
        }
        dns_rdataset_disassociate(&rdataset);
        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;
failure:
        if (node != NULL)
                dns_db_detachnode(db, &node);
        return (result);
}

static isc_result_t
add_exposed_sigs(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
                 dns_dbversion_t *ver, dns_name_t *name, isc_boolean_t cut,
                 dns_diff_t *diff, dst_key_t **keys, unsigned int nkeys,
                 isc_stdtime_t inception, isc_stdtime_t expire,
                 isc_boolean_t check_ksk, isc_boolean_t keyset_kskonly,
                 unsigned int *sigs)
{
        isc_result_t result;
        dns_dbnode_t *node;
        dns_rdatasetiter_t *iter;

        node = NULL;
        result = dns_db_findnode(db, name, ISC_FALSE, &node);
        if (result == ISC_R_NOTFOUND)
                return (ISC_R_SUCCESS);
        if (result != ISC_R_SUCCESS)
                return (result);

        iter = NULL;
        result = dns_db_allrdatasets(db, node, ver,
                                     (isc_stdtime_t) 0, &iter);
        if (result != ISC_R_SUCCESS)
                goto cleanup_node;

        for (result = dns_rdatasetiter_first(iter);
             result == ISC_R_SUCCESS;
             result = dns_rdatasetiter_next(iter))
        {
                dns_rdataset_t rdataset;
                dns_rdatatype_t type;
                isc_boolean_t flag;

                dns_rdataset_init(&rdataset);
                dns_rdatasetiter_current(iter, &rdataset);
                type = rdataset.type;
                dns_rdataset_disassociate(&rdataset);

                /*
                 * We don't need to sign unsigned NSEC records at the cut
                 * as they are handled elsewhere.
                 */
                if ((type == dns_rdatatype_rrsig) ||
                    (cut && type != dns_rdatatype_ds))
                        continue;
                result = rrset_exists(db, ver, name, dns_rdatatype_rrsig,
                                      type, &flag);
                if (result != ISC_R_SUCCESS)
                        goto cleanup_iterator;
                if (flag)
                        continue;;
                result = add_sigs(log, zone, db, ver, name, type, diff,
                                  keys, nkeys, inception, expire,
                                  check_ksk, keyset_kskonly);
                if (result != ISC_R_SUCCESS)
                        goto cleanup_iterator;
                (*sigs)++;
        }
        if (result == ISC_R_NOMORE)
                result = ISC_R_SUCCESS;

 cleanup_iterator:
        dns_rdatasetiter_destroy(&iter);

 cleanup_node:
        dns_db_detachnode(db, &node);

        return (result);
}

/*%
 * Update RRSIG, NSEC and NSEC3 records affected by an update.  The original
 * update, including the SOA serial update but excluding the RRSIG & NSEC
 * changes, is in "diff" and has already been applied to "newver" of "db".
 * The database version prior to the update is "oldver".
 *
 * The necessary RRSIG, NSEC and NSEC3 changes will be applied to "newver"
 * and added (as a minimal diff) to "diff".
 *
 * The RRSIGs generated will be valid for 'sigvalidityinterval' seconds.
 */
isc_result_t
dns_update_signatures(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
                      dns_dbversion_t *oldver, dns_dbversion_t *newver,
                      dns_diff_t *diff, isc_uint32_t sigvalidityinterval)
{
        return (dns_update_signaturesinc(log, zone, db, oldver, newver, diff,
                                         sigvalidityinterval, NULL));
}

struct dns_update_state {
        unsigned int magic;
        dns_diff_t diffnames;
        dns_diff_t affected;
        dns_diff_t sig_diff;
        dns_diff_t nsec_diff;
        dns_diff_t nsec_mindiff;
        dns_diff_t work;
        dst_key_t *zone_keys[DNS_MAXZONEKEYS];
        unsigned int nkeys;
        isc_stdtime_t inception, expire;
        dns_ttl_t nsecttl;
        isc_boolean_t check_ksk, keyset_kskonly;
        enum { sign_updates, remove_orphaned, build_chain, process_nsec,
               sign_nsec, update_nsec3, process_nsec3, sign_nsec3 } state;
};

isc_result_t
dns_update_signaturesinc(dns_update_log_t *log, dns_zone_t *zone, dns_db_t *db,
                         dns_dbversion_t *oldver, dns_dbversion_t *newver,
                         dns_diff_t *diff, isc_uint32_t sigvalidityinterval,
                         dns_update_state_t **statep)
{
        isc_result_t result = ISC_R_SUCCESS;
        dns_update_state_t mystate, *state;

        dns_difftuple_t *t, *next;
        isc_boolean_t flag, build_nsec, build_nsec3;
        unsigned int i;
        isc_stdtime_t now;
        dns_rdata_soa_t soa;
        dns_rdata_t rdata = DNS_RDATA_INIT;
        dns_rdataset_t rdataset;
        dns_dbnode_t *node = NULL;
        isc_boolean_t unsecure;
        isc_boolean_t cut;
        dns_rdatatype_t privatetype = dns_zone_getprivatetype(zone);
        unsigned int sigs = 0;
        unsigned int maxsigs = dns_zone_getsignatures(zone);

        if (statep == NULL || (statep != NULL && *statep == NULL)) {
                if (statep == NULL) {
                        state = &mystate;
                } else {
                        state = isc_mem_get(diff->mctx, sizeof(*state));
                        if (state == NULL)
                                return (ISC_R_NOMEMORY);
                }

                dns_diff_init(diff->mctx, &state->diffnames);
                dns_diff_init(diff->mctx, &state->affected);
                dns_diff_init(diff->mctx, &state->sig_diff);
                dns_diff_init(diff->mctx, &state->nsec_diff);
                dns_diff_init(diff->mctx, &state->nsec_mindiff);
                dns_diff_init(diff->mctx, &state->work);
                state->nkeys = 0;

                result = find_zone_keys(zone, db, newver, diff->mctx,
                                        DNS_MAXZONEKEYS, state->zone_keys,
                                        &state->nkeys);
                if (result != ISC_R_SUCCESS) {
                        update_log(log, zone, ISC_LOG_ERROR,
                                   "could not get zone keys for secure "
                                   "dynamic update");
                        goto failure;
                }

                isc_stdtime_get(&now);
                state->inception = now - 3600; /* Allow for some clock skew. */
                state->expire = now + sigvalidityinterval;

                /*
                 * Do we look at the KSK flag on the DNSKEY to determining which
                 * keys sign which RRsets?  First check the zone option then
                 * check the keys flags to make sure at least one has a ksk set
                 * and one doesn't.
                 */
                state->check_ksk = ISC_TF((dns_zone_getoptions(zone) &
                                    DNS_ZONEOPT_UPDATECHECKKSK) != 0);
                state->keyset_kskonly = ISC_TF((dns_zone_getoptions(zone) &
                                        DNS_ZONEOPT_DNSKEYKSKONLY) != 0);

                /*
                 * Get the NSEC/NSEC3 TTL from the SOA MINIMUM field.
                 */
                CHECK(dns_db_findnode(db, dns_db_origin(db), ISC_FALSE, &node));
                dns_rdataset_init(&rdataset);
                CHECK(dns_db_findrdataset(db, node, newver, dns_rdatatype_soa,
                                          0, (isc_stdtime_t) 0, &rdataset,
                                          NULL));
                CHECK(dns_rdataset_first(&rdataset));
                dns_rdataset_current(&rdataset, &rdata);
                CHECK(dns_rdata_tostruct(&rdata, &soa, NULL));
                state->nsecttl = soa.minimum;
                dns_rdataset_disassociate(&rdataset);
                dns_db_detachnode(db, &node);

                /*
                 * Find all RRsets directly affected by the update, and
                 * update their RRSIGs.  Also build a list of names affected
                 * by the update in "diffnames".
                 */
                CHECK(dns_diff_sort(diff, temp_order));
                state->state = sign_updates;
                state->magic = STATE_MAGIC;
                if (statep != NULL)
                        *statep = state;
        } else {
                REQUIRE(DNS_STATE_VALID(*statep));
                state = *statep;
        }

 next_state:
        switch (state->state) {
        case sign_updates:
                t = ISC_LIST_HEAD(diff->tuples);
                while (t != NULL) {
                        dns_name_t *name = &t->name;
                        /*
                         * Now "name" is a new, unique name affected by the
                         * update.
                         */

                        CHECK(namelist_append_name(&state->diffnames, name));

                        while (t != NULL && dns_name_equal(&t->name, name)) {
                                dns_rdatatype_t type;
                                type = t->rdata.type;

                                /*
                                 * Now "name" and "type" denote a new unique
                                 * RRset affected by the update.
                                 */

                                /* Don't sign RRSIGs. */
                                if (type == dns_rdatatype_rrsig)
                                        goto skip;

                                /*
                                 * Delete all old RRSIGs covering this type,
                                 * since they are all invalid when the signed
                                 * RRset has changed.  We may not be able to
                                 * recreate all of them - tough.
                                 * Special case changes to the zone's DNSKEY
                                 * records to support offline KSKs.
                                 */
                                if (type == dns_rdatatype_dnskey)
                                        del_keysigs(db, newver, name,
                                                    &state->sig_diff,
                                                    state->zone_keys,
                                                    state->nkeys);
                                else
                                        CHECK(delete_if(true_p, db, newver,
                                                        name,
                                                        dns_rdatatype_rrsig,
                                                        type, NULL,
                                                        &state->sig_diff));

                                /*
                                 * If this RRset is still visible after the
                                 * update, add a new signature for it.
                                 */
                                CHECK(rrset_visible(db, newver, name, type,
                                                   &flag));
                                if (flag) {
                                        CHECK(add_sigs(log, zone, db, newver,
                                                       name, type,
                                                       &state->sig_diff,
                                                       state->zone_keys,
                                                       state->nkeys,
                                                       state->inception,
                                                       state->expire,
                                                       state->check_ksk,
                                                       state->keyset_kskonly));
                                        sigs++;
                                }
                        skip:
                                /* Skip any other updates to the same RRset. */
                                while (t != NULL &&
                                       dns_name_equal(&t->name, name) &&
                                       t->rdata.type == type)
                                {
                                        next = ISC_LIST_NEXT(t, link);
                                        ISC_LIST_UNLINK(diff->tuples, t, link);
                                        ISC_LIST_APPEND(state->work.tuples, t,
                                                        link);
                                        t = next;
                                }
                        }
                        if (state != &mystate && sigs > maxsigs)
                                return (DNS_R_CONTINUE);
                }
                ISC_LIST_APPENDLIST(diff->tuples, state->work.tuples, link);

                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "updated data signatures");
                /*FALLTHROUGH*/
        case remove_orphaned:
                state->state = remove_orphaned;

                /* Remove orphaned NSECs and RRSIG NSECs. */
                for (t = ISC_LIST_HEAD(state->diffnames.tuples);
                     t != NULL;
                     t = ISC_LIST_NEXT(t, link))
                {
                        CHECK(non_nsec_rrset_exists(db, newver,
                                                    &t->name, &flag));
                        if (!flag) {
                                CHECK(delete_if(true_p, db, newver, &t->name,
                                                dns_rdatatype_any, 0,
                                                NULL, &state->sig_diff));
                        }
                }
                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "removed any orphaned NSEC records");

                /*
                 * See if we need to build NSEC or NSEC3 chains.
                 */
                CHECK(dns_private_chains(db, newver, privatetype, &build_nsec,
                                         &build_nsec3));
                if (!build_nsec) {
                        state->state = update_nsec3;
                        goto next_state;
                }

                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "rebuilding NSEC chain");

                /*FALLTHROUGH*/
        case build_chain:
                state->state = build_chain;
                /*
                 * When a name is created or deleted, its predecessor needs to
                 * have its NSEC updated.
                 */
                for (t = ISC_LIST_HEAD(state->diffnames.tuples);
                     t != NULL;
                     t = ISC_LIST_NEXT(t, link))
                {
                        isc_boolean_t existed, exists;
                        dns_fixedname_t fixedname;
                        dns_name_t *prevname;

                        dns_fixedname_init(&fixedname);
                        prevname = dns_fixedname_name(&fixedname);

                        if (oldver != NULL)
                                CHECK(name_exists(db, oldver, &t->name,
                                                  &existed));
                        else
                                existed = ISC_FALSE;
                        CHECK(name_exists(db, newver, &t->name, &exists));
                        if (exists == existed)
                                continue;

                        /*
                         * Find the predecessor.
                         * When names become obscured or unobscured in this
                         * update transaction, we may find the wrong
                         * predecessor because the NSECs have not yet been
                         * updated to reflect the delegation change.  This
                         * should not matter because in this case, the correct
                         * predecessor is either the delegation node or a
                         * newly unobscured node, and those nodes are on the
                         * "affected" list in any case.
                         */
                        CHECK(next_active(log, zone, db, newver,
                                          &t->name, prevname, ISC_FALSE));
                        CHECK(namelist_append_name(&state->affected, prevname));
                }

                /*
                 * Find names potentially affected by delegation changes
                 * (obscured by adding an NS or DNAME, or unobscured by
                 * removing one).
                 */
                for (t = ISC_LIST_HEAD(state->diffnames.tuples);
                     t != NULL;
                     t = ISC_LIST_NEXT(t, link))
                {
                        isc_boolean_t ns_existed, dname_existed;
                        isc_boolean_t ns_exists, dname_exists;

                        if (oldver != NULL)
                                CHECK(rrset_exists(db, oldver, &t->name,
                                                  dns_rdatatype_ns, 0,
                                                  &ns_existed));
                        else
                                ns_existed = ISC_FALSE;
                        if (oldver != NULL)
                                CHECK(rrset_exists(db, oldver, &t->name,
                                                   dns_rdatatype_dname, 0,
                                                   &dname_existed));
                        else
                                dname_existed = ISC_FALSE;
                        CHECK(rrset_exists(db, newver, &t->name,
                                           dns_rdatatype_ns, 0, &ns_exists));
                        CHECK(rrset_exists(db, newver, &t->name,
                                           dns_rdatatype_dname, 0,
                                           &dname_exists));
                        if ((ns_exists || dname_exists) ==
                            (ns_existed || dname_existed))
                                continue;
                        /*
                         * There was a delegation change.  Mark all subdomains
                         * of t->name as potentially needing a NSEC update.
                         */
                        CHECK(namelist_append_subdomain(db, &t->name,
                                                        &state->affected));
                }
                ISC_LIST_APPENDLIST(state->affected.tuples,
                                    state->diffnames.tuples, link);
                INSIST(ISC_LIST_EMPTY(state->diffnames.tuples));

                CHECK(uniqify_name_list(&state->affected));

                /*FALLTHROUGH*/
        case process_nsec:
                state->state = process_nsec;

                /*
                 * Determine which names should have NSECs, and delete/create
                 * NSECs to make it so.  We don't know the final NSEC targets
                 * yet, so we just create placeholder NSECs with arbitrary
                 * contents to indicate that their respective owner names
                 * should be part of the NSEC chain.
                 */
                while ((t = ISC_LIST_HEAD(state->affected.tuples)) != NULL) {
                        isc_boolean_t exists;
                        dns_name_t *name = &t->name;

                        CHECK(name_exists(db, newver, name, &exists));
                        if (! exists)
                                goto unlink;
                        CHECK(is_active(db, newver, name, &flag, &cut, NULL));
                        if (!flag) {
                                /*
                                 * This name is obscured.  Delete any
                                 * existing NSEC record.
                                 */
                                CHECK(delete_if(true_p, db, newver, name,
                                                dns_rdatatype_nsec, 0,
                                                NULL, &state->nsec_diff));
                                CHECK(delete_if(rrsig_p, db, newver, name,
                                                dns_rdatatype_any, 0, NULL,
                                                diff));
                        } else {
                                /*
                                 * This name is not obscured.  It needs to have
                                 * a NSEC unless it is the at the origin, in
                                 * which case it should already exist if there
                                 * is a complete NSEC chain and if there isn't
                                 * a complete NSEC chain we don't want to add
                                 * one as that would signal that there is a
                                 * complete NSEC chain.
                                 */
                                if (!dns_name_equal(name, dns_db_origin(db))) {
                                        CHECK(rrset_exists(db, newver, name,
                                                           dns_rdatatype_nsec,
                                                           0, &flag));
                                        if (!flag)
                                                CHECK(add_placeholder_nsec(db,
                                                          newver, name, diff));
                                }
                                CHECK(add_exposed_sigs(log, zone, db, newver,
                                                       name, cut,
                                                       &state->sig_diff,
                                                       state->zone_keys,
                                                       state->nkeys,
                                                       state->inception,
                                                       state->expire,
                                                       state->check_ksk,
                                                       state->keyset_kskonly,
                                                       &sigs));
                        }
         unlink:
                        ISC_LIST_UNLINK(state->affected.tuples, t, link);
                        ISC_LIST_APPEND(state->work.tuples, t, link);
                        if (state != &mystate && sigs > maxsigs)
                                return (DNS_R_CONTINUE);
                }
                ISC_LIST_APPENDLIST(state->affected.tuples,
                                    state->work.tuples, link);

                /*
                 * Now we know which names are part of the NSEC chain.
                 * Make them all point at their correct targets.
                 */
                for (t = ISC_LIST_HEAD(state->affected.tuples);
                     t != NULL;
                     t = ISC_LIST_NEXT(t, link))
                {
                        CHECK(rrset_exists(db, newver, &t->name,
                                           dns_rdatatype_nsec, 0, &flag));
                        if (flag) {
                                /*
                                 * There is a NSEC, but we don't know if it
                                 * is correct. Delete it and create a correct
                                 * one to be sure. If the update was
                                 * unnecessary, the diff minimization
                                 * will take care of eliminating it from the
                                 * journal, IXFRs, etc.
                                 *
                                 * The RRSIG bit should always be set in the
                                 * NSECs we generate, because they will all
                                 * get RRSIG NSECs.
                                 * (XXX what if the zone keys are missing?).
                                 * Because the RRSIG NSECs have not necessarily
                                 * been created yet, the correctness of the
                                 * bit mask relies on the assumption that NSECs
                                 * are only created if there is other data, and
                                 * if there is other data, there are other
                                 * RRSIGs.
                                 */
                                CHECK(add_nsec(log, zone, db, newver, &t->name,
                                               state->nsecttl,
                                               &state->nsec_diff));
                        }
                }

                /*
                 * Minimize the set of NSEC updates so that we don't
                 * have to regenerate the RRSIG NSECs for NSECs that were
                 * replaced with identical ones.
                 */
                while ((t = ISC_LIST_HEAD(state->nsec_diff.tuples)) != NULL) {
                        ISC_LIST_UNLINK(state->nsec_diff.tuples, t, link);
                        dns_diff_appendminimal(&state->nsec_mindiff, &t);
                }

                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "signing rebuilt NSEC chain");

                /*FALLTHROUGH*/
        case sign_nsec:
                state->state = sign_nsec;
                /* Update RRSIG NSECs. */
                while ((t = ISC_LIST_HEAD(state->nsec_mindiff.tuples)) != NULL)
                {
                        if (t->op == DNS_DIFFOP_DEL) {
                                CHECK(delete_if(true_p, db, newver, &t->name,
                                                dns_rdatatype_rrsig,
                                                dns_rdatatype_nsec,
                                                NULL, &state->sig_diff));
                        } else if (t->op == DNS_DIFFOP_ADD) {
                                CHECK(add_sigs(log, zone, db, newver, &t->name,
                                               dns_rdatatype_nsec,
                                               &state->sig_diff,
                                               state->zone_keys, state->nkeys,
                                               state->inception, state->expire,
                                               state->check_ksk,
                                               state->keyset_kskonly));
                                sigs++;
                        } else {
                                INSIST(0);
                        }
                        ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
                        ISC_LIST_APPEND(state->work.tuples, t, link);
                        if (state != &mystate && sigs > maxsigs)
                                return (DNS_R_CONTINUE);
                }
                ISC_LIST_APPENDLIST(state->nsec_mindiff.tuples,
                                    state->work.tuples, link);
                /*FALLTHROUGH*/
        case update_nsec3:
                state->state = update_nsec3;

                /* Record our changes for the journal. */
                while ((t = ISC_LIST_HEAD(state->sig_diff.tuples)) != NULL) {
                        ISC_LIST_UNLINK(state->sig_diff.tuples, t, link);
                        dns_diff_appendminimal(diff, &t);
                }
                while ((t = ISC_LIST_HEAD(state->nsec_mindiff.tuples)) != NULL)
                {
                        ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
                        dns_diff_appendminimal(diff, &t);
                }

                INSIST(ISC_LIST_EMPTY(state->sig_diff.tuples));
                INSIST(ISC_LIST_EMPTY(state->nsec_diff.tuples));
                INSIST(ISC_LIST_EMPTY(state->nsec_mindiff.tuples));

                if (!build_nsec3) {
                        update_log(log, zone, ISC_LOG_DEBUG(3),
                                   "no NSEC3 chains to rebuild");
                        goto failure;
                }

                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "rebuilding NSEC3 chains");

                dns_diff_clear(&state->diffnames);
                dns_diff_clear(&state->affected);

                CHECK(dns_diff_sort(diff, temp_order));

                /*
                 * Find names potentially affected by delegation changes
                 * (obscured by adding an NS or DNAME, or unobscured by
                 * removing one).
                 */
                t = ISC_LIST_HEAD(diff->tuples);
                while (t != NULL) {
                        dns_name_t *name = &t->name;

                        isc_boolean_t ns_existed, dname_existed;
                        isc_boolean_t ns_exists, dname_exists;
                        isc_boolean_t exists, existed;

                        if (t->rdata.type == dns_rdatatype_nsec ||
                            t->rdata.type == dns_rdatatype_rrsig) {
                                t = ISC_LIST_NEXT(t, link);
                                continue;
                        }

                        CHECK(namelist_append_name(&state->affected, name));

                        if (oldver != NULL)
                                CHECK(rrset_exists(db, oldver, name,
                                                   dns_rdatatype_ns,
                                                   0, &ns_existed));
                        else
                                ns_existed = ISC_FALSE;
                        if (oldver != NULL)
                                CHECK(rrset_exists(db, oldver, name,
                                                   dns_rdatatype_dname, 0,
                                                   &dname_existed));
                        else
                                dname_existed = ISC_FALSE;
                        CHECK(rrset_exists(db, newver, name, dns_rdatatype_ns,
                                           0, &ns_exists));
                        CHECK(rrset_exists(db, newver, name,
                                           dns_rdatatype_dname, 0,
                                           &dname_exists));

                        exists = ns_exists || dname_exists;
                        existed = ns_existed || dname_existed;
                        if (exists == existed)
                                goto nextname;
                        /*
                         * There was a delegation change.  Mark all subdomains
                         * of t->name as potentially needing a NSEC3 update.
                         */
                        CHECK(namelist_append_subdomain(db, name,
                                                        &state->affected));

        nextname:
                        while (t != NULL && dns_name_equal(&t->name, name))
                                t = ISC_LIST_NEXT(t, link);
                }

                /*FALLTHROUGH*/
        case process_nsec3:
                state->state = process_nsec3;
                while ((t = ISC_LIST_HEAD(state->affected.tuples)) != NULL) {
                        dns_name_t *name = &t->name;

                        unsecure = ISC_FALSE;   /* Silence compiler warning. */
                        CHECK(is_active(db, newver, name, &flag, &cut,
                                        &unsecure));

                        if (!flag) {
                                CHECK(delete_if(rrsig_p, db, newver, name,
                                                dns_rdatatype_any, 0, NULL,
                                                diff));
                                CHECK(dns_nsec3_delnsec3sx(db, newver, name,
                                                           privatetype,
                                                           &state->nsec_diff));
                        } else {
                                CHECK(add_exposed_sigs(log, zone, db, newver,
                                                       name, cut,
                                                       &state->sig_diff,
                                                       state->zone_keys,
                                                       state->nkeys,
                                                       state->inception,
                                                       state->expire,
                                                       state->check_ksk,
                                                       state->keyset_kskonly,
                                                       &sigs));
                                CHECK(dns_nsec3_addnsec3sx(db, newver, name,
                                                           state->nsecttl,
                                                           unsecure,
                                                           privatetype,
                                                           &state->nsec_diff));
                        }
                        ISC_LIST_UNLINK(state->affected.tuples, t, link);
                        ISC_LIST_APPEND(state->work.tuples, t, link);
                        if (state != &mystate && sigs > maxsigs)
                                return (DNS_R_CONTINUE);
                }
                ISC_LIST_APPENDLIST(state->affected.tuples,
                                    state->work.tuples, link);

                /*
                 * Minimize the set of NSEC3 updates so that we don't
                 * have to regenerate the RRSIG NSEC3s for NSEC3s that were
                 * replaced with identical ones.
                 */
                while ((t = ISC_LIST_HEAD(state->nsec_diff.tuples)) != NULL) {
                        ISC_LIST_UNLINK(state->nsec_diff.tuples, t, link);
                        dns_diff_appendminimal(&state->nsec_mindiff, &t);
                }

                update_log(log, zone, ISC_LOG_DEBUG(3),
                           "signing rebuilt NSEC3 chain");

                /*FALLTHROUGH*/
        case sign_nsec3:
                state->state = sign_nsec3;
                /* Update RRSIG NSEC3s. */
                while ((t = ISC_LIST_HEAD(state->nsec_mindiff.tuples)) != NULL)
                {
                        if (t->op == DNS_DIFFOP_DEL) {
                                CHECK(delete_if(true_p, db, newver, &t->name,
                                                dns_rdatatype_rrsig,
                                                dns_rdatatype_nsec3,
                                                NULL, &state->sig_diff));
                        } else if (t->op == DNS_DIFFOP_ADD) {
                                CHECK(add_sigs(log, zone, db, newver, &t->name,
                                               dns_rdatatype_nsec3,
                                               &state->sig_diff,
                                               state->zone_keys,
                                               state->nkeys, state->inception,
                                               state->expire, state->check_ksk,
                                               state->keyset_kskonly));
                                sigs++;
                        } else {
                                INSIST(0);
                        }
                        ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
                        ISC_LIST_APPEND(state->work.tuples, t, link);
                        if (state != &mystate && sigs > maxsigs)
                                return (DNS_R_CONTINUE);
                }
                ISC_LIST_APPENDLIST(state->nsec_mindiff.tuples,
                                    state->work.tuples, link);

                /* Record our changes for the journal. */
                while ((t = ISC_LIST_HEAD(state->sig_diff.tuples)) != NULL) {
                        ISC_LIST_UNLINK(state->sig_diff.tuples, t, link);
                        dns_diff_appendminimal(diff, &t);
                }
                while ((t = ISC_LIST_HEAD(state->nsec_mindiff.tuples)) != NULL)
                {
                        ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
                        dns_diff_appendminimal(diff, &t);
                }

                INSIST(ISC_LIST_EMPTY(state->sig_diff.tuples));
                INSIST(ISC_LIST_EMPTY(state->nsec_diff.tuples));
                INSIST(ISC_LIST_EMPTY(state->nsec_mindiff.tuples));
                break;
        default:
                INSIST(0);
        }

 failure:
        dns_diff_clear(&state->sig_diff);
        dns_diff_clear(&state->nsec_diff);
        dns_diff_clear(&state->nsec_mindiff);

        dns_diff_clear(&state->affected);
        dns_diff_clear(&state->diffnames);
        dns_diff_clear(&state->work);

        for (i = 0; i < state->nkeys; i++)
                dst_key_free(&state->zone_keys[i]);

        if (state != &mystate && state != NULL) {
                *statep = NULL;
                state->magic = 0;
                isc_mem_put(diff->mctx, state, sizeof(*state));
        }

        return (result);
}

static isc_stdtime_t
epoch_to_yyyymmdd(time_t when) {
        struct tm *tm;
        tm = localtime(&when);
        return (((tm->tm_year + 1900) * 10000) +
                ((tm->tm_mon + 1) * 100) + tm->tm_mday);
}

isc_uint32_t
dns_update_soaserial(isc_uint32_t serial, dns_updatemethod_t method) {
        isc_stdtime_t now;
        isc_uint32_t new_serial;

        switch (method) {
        case dns_updatemethod_none:
                return (serial);
        case dns_updatemethod_unixtime:
                isc_stdtime_get(&now);
                if (now != 0 && isc_serial_gt(now, serial))
                        return (now);
                break;
        case dns_updatemethod_date:
                isc_stdtime_get(&now);
                new_serial = epoch_to_yyyymmdd((time_t) now) * 100;
                if (new_serial != 0 && isc_serial_gt(new_serial, serial))
                        return (new_serial);
        case dns_updatemethod_increment:
                break;
        }

        /* RFC1982 */
        serial = (serial + 1) & 0xFFFFFFFF;
        if (serial == 0)
                serial = 1;

        return (serial);
}

---