bin/named/server.c

	server.c revision 71385229ce0f2c7d277ca16bbc554bb3bdf9f587
/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM 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 <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>

#include <isc/app.h>
#include <isc/assertions.h>
#include <isc/dir.h>
#include <isc/error.h>
#include <isc/mem.h>
#include <isc/result.h>
#include <isc/rwlock.h>
#include <isc/socket.h>
#include <isc/task.h>
#include <isc/thread.h>
#include <isc/timer.h>
#include <isc/util.h>

#include <dns/acl.h>
#include <dns/aclconf.h>
#include <dns/cache.h>
#include <dns/confacl.h>
#include <dns/confctx.h>
#include <dns/confip.h>
#include <dns/confparser.h>
#include <dns/db.h>
#include <dns/dispatch.h>
#include <dns/fixedname.h>
#include <dns/journal.h>
#include <dns/master.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/rootns.h>
#include <dns/tkeyconf.h>
#include <dns/tsigconf.h>
#include <dns/types.h>
#include <dns/view.h>
#include <dns/zone.h>
#include <dns/zoneconf.h>

#include <named/client.h>
#include <named/globals.h>
#include <named/interfacemgr.h>
#include <named/listenlist.h>
#include <named/log.h>
#include <named/os.h>
#include <named/server.h>
#include <named/types.h>

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

#define CHECKM(op, msg) \
    do { result = (op);                       \
           if (result != ISC_R_SUCCESS) {             \
            isc_log_write(ns_g_lctx,          \
                      NS_LOGCATEGORY_GENERAL,     \
                      NS_LOGMODULE_SERVER,    \
                      ISC_LOG_ERROR,          \
                      "%s: %s", msg,          \
                      isc_result_totext(result)); \
            goto cleanup;                 \
        }                         \
    } while (0)                       \

#define CHECKFATAL(op, msg) \
    do { result = (op);                       \
           if (result != ISC_R_SUCCESS)           \
            fatal(msg, result);           \
    } while (0)                       \

typedef struct {
    isc_mem_t *     mctx;
    dns_viewlist_t      viewlist;
    dns_aclconfctx_t    *aclconf;
} ns_load_t;

static void fatal(char *msg, isc_result_t result);
static void ns_server_reload(isc_task_t *task, isc_event_t *event);

static isc_result_t
ns_listenelt_fromconfig(dns_c_lstnon_t *celt, dns_c_ctx_t *cctx,
            dns_aclconfctx_t *actx,
            isc_mem_t *mctx, ns_listenelt_t **target);
static isc_result_t
ns_listenlist_fromconfig(dns_c_lstnlist_t *clist, dns_c_ctx_t *cctx,
             dns_aclconfctx_t *actx,
             isc_mem_t *mctx, ns_listenlist_t **target);

/*
 * Configure 'view' according to 'cctx'.
 *
 * XXX reconfiguration should preserve cache contents.
 */
static isc_result_t
configure_view(dns_view_t *view, dns_c_ctx_t *cctx, isc_mem_t *mctx,
           dns_dispatch_t *dispatch)
{
    dns_cache_t *cache;
    isc_result_t result;
    isc_int32_t cleaning_interval;
    dns_tsig_keyring_t *ring;
    dns_c_forw_t forward;
    dns_c_iplist_t *forwarders;
    dns_fwdpolicy_t fwdpolicy;
    isc_sockaddrlist_t addresses;
    isc_sockaddr_t *sa, *next_sa;
    unsigned int i;

    REQUIRE(DNS_VIEW_VALID(view));

    ISC_LIST_INIT(addresses);

    RWLOCK(&view->conflock, isc_rwlocktype_write);

    /*
     * Cache.
     */
    cache = NULL;
    CHECK(dns_cache_create(mctx, ns_g_taskmgr, ns_g_timermgr,
                   view->rdclass, "rbt", 0, NULL, &cache));
    dns_view_setcache(view, cache);
    cleaning_interval = 3600; /* Default is 1 hour. */
    (void) dns_c_ctx_getcleaninterval(cctx, &cleaning_interval);
    dns_cache_setcleaninginterval(cache, cleaning_interval);
    dns_cache_detach(&cache);

    /*
     * XXXRTH  Temporary support for loading cache contents.
     */
    if (ns_g_cachefile != NULL) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER,
                  ISC_LOG_DEBUG(1), "loading cache '%s'",
                  ns_g_cachefile);
        CHECK(dns_db_load(view->cachedb, ns_g_cachefile));
    }

    /*
     * Resolver.
     *
     * XXXRTH  Hardwired number of tasks.
     */
    CHECK(dns_view_createresolver(view, ns_g_taskmgr, 31,
                      ns_g_socketmgr, ns_g_timermgr,
                      0, dispatch, NULL));

    /*
     * Set resolver forwarding policy.
     */
    if (dns_c_ctx_getforwarders(cctx, &forwarders) == ISC_R_SUCCESS) {
        fwdpolicy = dns_fwdpolicy_first;
        /*
         * Ugh.  Convert between list formats.
         */
        for (i = 0; i < forwarders->nextidx; i++) {
            sa = isc_mem_get(view->mctx, sizeof *sa);
            if (sa == NULL) {
                result = ISC_R_NOMEMORY;
                goto cleanup;
            }
            *sa = forwarders->ips[i];
            isc_sockaddr_setport(sa, 53);
            ISC_LINK_INIT(sa, link);
            ISC_LIST_APPEND(addresses, sa, link);
        }
        INSIST(!ISC_LIST_EMPTY(addresses));
        dns_c_iplist_detach(&forwarders);
        CHECK(dns_resolver_setforwarders(view->resolver, &addresses));
        /*
         * XXXRTH  The configuration type 'dns_c_forw_t' should be
         *         elminated.
         */
        if (dns_c_ctx_getforward(cctx, &forward) == ISC_R_SUCCESS) {
            INSIST(forward == dns_c_forw_first ||
                   forward == dns_c_forw_only);
            if (forward == dns_c_forw_only)
                fwdpolicy = dns_fwdpolicy_only;
        }
        CHECK(dns_resolver_setfwdpolicy(view->resolver, fwdpolicy));
    }

    /*
     * We have default hints for class IN if we need them.
     */
    if (view->rdclass == dns_rdataclass_in && view->hints == NULL)
        dns_view_sethints(view, ns_g_server->roothints);

    /*
     * Configure the view's TSIG keys.
     */
    ring = NULL;
    CHECK(dns_tsigkeyring_fromconfig(cctx, view->mctx, &ring));
    dns_view_setkeyring(view, ring);

 cleanup:
    RWUNLOCK(&view->conflock, isc_rwlocktype_write);

    for (sa = ISC_LIST_HEAD(addresses);
         sa != NULL;
         sa = next_sa) {
        next_sa = ISC_LIST_NEXT(sa, link);
        isc_mem_put(view->mctx, sa, sizeof *sa);
    }

    return (result);
}

/*
 * Create the special view that handles queries for
 * "version.bind. CH".   The version string returned is that
 * configured in 'configctx', or a compiled-in default if
 * there is no "version" configuration option.
 */
static isc_result_t
create_version_view(dns_c_ctx_t *configctx, dns_view_t **viewp) {
    isc_result_t result;
    dns_db_t *db = NULL;
    dns_zone_t *zone = NULL;
    dns_dbversion_t *dbver = NULL;
    dns_difftuple_t *tuple = NULL;
    dns_diff_t diff;
    dns_view_t *view = NULL;
    char *versiontext;
    unsigned char buf[256];
    isc_region_t r;
    size_t len;
    dns_rdata_t rdata;
    static unsigned char origindata[] = "\007version\004bind";
    dns_name_t origin;

    REQUIRE(viewp != NULL && *viewp == NULL);

    dns_diff_init(ns_g_mctx, &diff);

    dns_name_init(&origin, NULL);
    r.base = origindata;
    r.length = sizeof(origindata);
    dns_name_fromregion(&origin, &r);

    (void) dns_c_ctx_getversion(configctx, &versiontext);
    if (versiontext == NULL)
        versiontext = ns_g_version;
    len = strlen(versiontext);
    if (len > 255)
        len = 255; /* Silently truncate. */
    buf[0] = len;
    memcpy(buf + 1, versiontext, len);

    r.base = buf;
    r.length = 1 + len;
    dns_rdata_fromregion(&rdata, dns_rdataclass_ch, dns_rdatatype_txt, &r);

    CHECK(dns_zone_create(&zone, ns_g_mctx));
    CHECK(dns_zone_setorigin(zone, &origin));

    CHECK(dns_db_create(ns_g_mctx, "rbt", &origin, ISC_FALSE,
                dns_rdataclass_ch, 0, NULL, &db));

    CHECK(dns_db_newversion(db, &dbver));

    CHECK(dns_difftuple_create(ns_g_mctx, DNS_DIFFOP_ADD, &origin,
                   0, &rdata, &tuple));
    dns_diff_append(&diff, &tuple);
    CHECK(dns_diff_apply(&diff, db, dbver));

    dns_db_closeversion(db, &dbver, ISC_TRUE);

    CHECK(dns_view_create(ns_g_mctx, dns_rdataclass_ch, "_version",
                  &view));

    CHECK(dns_zone_replacedb(zone, db, ISC_FALSE));

    CHECK(dns_view_addzone(view, zone));

    dns_view_freeze(view);

    /* Transfer ownership. */
    *viewp = view;
    view = NULL;

    result = ISC_R_SUCCESS;

 cleanup:
    if (view != NULL)
        dns_view_detach(&view);
    if (zone != NULL)
        dns_zone_detach(&zone);
    if (dbver != NULL)
        dns_db_closeversion(db, &dbver, ISC_FALSE);
    if (db != NULL)
        dns_db_detach(&db);
    dns_diff_clear(&diff);

    return (result);
}

static isc_result_t
configure_hints(dns_view_t *view, const char *filename) {
    isc_result_t result;
    dns_db_t *db;

    db = NULL;
    result = dns_rootns_create(view->mctx, view->rdclass, filename, &db);
    if (result == ISC_R_SUCCESS) {
        dns_view_sethints(view, db);
        dns_db_detach(&db);
    }

    return (result);
}

/*
 * Configure or reconfigure a zone.  This callback function
 * is called after parsing each "zone" statement in named.conf.
 */
static isc_result_t
configure_zone(dns_c_ctx_t *cctx, dns_c_zone_t *czone, dns_c_view_t *cview,
      void *uap)
{
    ns_load_t *lctx = (ns_load_t *) uap;
    dns_view_t *view = NULL;    /* New view */
    dns_view_t *pview = NULL;   /* Production view */
    dns_zone_t *zone = NULL;    /* New or reused zone */
    dns_zone_t *tzone = NULL;   /* Temporary zone */
    char *viewname;

    isc_result_t result;

    char *corigin;
    isc_buffer_t buffer;
    dns_fixedname_t fixorigin;
    dns_name_t *origin;

    /*
     * Get the zone origin as a dns_name_t.
     */
    corigin = NULL;
    /* XXX casting away const */
    CHECK(dns_c_zone_getname(czone, (const char **) &corigin));
    isc_buffer_init(&buffer, corigin, strlen(corigin),
            ISC_BUFFERTYPE_TEXT);
    isc_buffer_add(&buffer, strlen(corigin));
    dns_fixedname_init(&fixorigin);
    CHECK(dns_name_fromtext(dns_fixedname_name(&fixorigin),
                &buffer, dns_rootname, ISC_FALSE, NULL));
    origin = dns_fixedname_name(&fixorigin);

    /*
     * Find or create the view in the new view list.
     */
    view = NULL;
    if (cview != NULL)
        viewname = cview->name;
    else
        viewname = "_default";
    result = dns_viewlist_find(&lctx->viewlist, viewname,
                   czone->zclass, &view);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (view == NULL) {
        dns_view_t *tview = NULL;
        CHECK(dns_view_create(ns_g_mctx, czone->zclass,
                      viewname, &view));
        dns_view_attach(view, &tview);
        ISC_LIST_APPEND(lctx->viewlist, tview, link);
    }

    /*
     * Master zones must have 'file' set.
     */
    if (czone->ztype == dns_c_zone_master &&
        czone->u.mzone.file == NULL) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "zone '%s': 'file' not specified",
                  corigin);
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /*
     * "hints zones" aren't zones.  If we've got one,
     * configure it and return.
     */
    if (czone->ztype == dns_c_zone_hint) {
        if (czone->u.hzone.file == NULL) {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                      "zone '%s': 'file' not specified",
                      corigin);
            result = ISC_R_FAILURE;
            goto cleanup;
        }
        if (dns_name_equal(origin, dns_rootname)) {
            result = configure_hints(view, czone->u.hzone.file);
        } else {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER, ISC_LOG_WARNING,
                      "ignoring non-root hint zone '%s'",
                      corigin);
            result = ISC_R_SUCCESS;
        }
        goto cleanup;
    }

    /*
     * "stub zones" aren't zones either.  Eventually we'll
     * create a "cache freshener" to keep the stub data in the
     * cache.
     */
    if (czone->ztype == dns_c_zone_stub) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_WARNING,
          "stub zone '%s': stub zones are not supported in this release",
                  corigin);
        result = ISC_R_SUCCESS;
        goto cleanup;
    }

    /*
     * "forward zones" aren't zones either.  Eventually we'll
     * translate this syntax into the appropriate selective forwarding
     * configuration.
     */
    if (czone->ztype == dns_c_zone_forward) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_WARNING,
      "forward zone '%s': forward zones are not supported in this release",
                  corigin);
        result = ISC_R_SUCCESS;
        goto cleanup;
    }

    /*
     * Check for duplicates in the new zone table.
     */
    result = dns_view_findzone(view, origin, &tzone);
    if (result == ISC_R_SUCCESS) {
        /*
         * We already have this zone!
         */
        result = ISC_R_EXISTS;
        goto cleanup;
    }

    /*
     * See if we can reuse an existing zone.  This is
     * only possible if all of these are true:
     *   - The zone's view exists
     *   - A zone with the right name exists in the view
     *   - The zone is compatible with the config
     *     options (e.g., an existing master zone cannot
     *     be reused if the options specify a slave zone)
     */
    result = dns_viewlist_find(&ns_g_server->viewlist,
                   view->name, view->rdclass,
                   &pview);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (pview != NULL)
        result = dns_view_findzone(pview, origin, &zone);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (zone != NULL) {
        if (! dns_zone_reusable(zone, czone))
            dns_zone_detach(&zone);
    }

    /*
     * If we cannot reuse an existing zone, we will have to
     * create a new one.
     */
    if (zone == NULL) {
        CHECK(dns_zone_create(&zone, lctx->mctx));
        CHECK(dns_zone_setorigin(zone, origin));
        CHECK(dns_zonemgr_managezone(ns_g_server->zonemgr,
                         zone));
    }

    /*
     * Configure the zone.
     */
    CHECK(dns_zone_configure(cctx, lctx->aclconf, czone, zone));

    /*
     * XXX Why was this here?
     *
     * if (dns_zone_gettype(zone) == dns_zone_hint)
     *      INSIST(0);
     */

    /*
     * Add the zone to its view in the new view list.
     */
    CHECK(dns_view_addzone(view, zone));

 cleanup:
    if (tzone != NULL)
        dns_zone_detach(&tzone);
    if (zone != NULL)
        dns_zone_detach(&zone);
    if (pview != NULL)
        dns_view_detach(&pview);
    if (view != NULL)
        dns_view_detach(&view);

    return (result);
}

/*
 * Configure a single server ACL at '*aclp'.  Get its configuration by
 * calling 'getacl'.
 */
static isc_result_t
configure_server_acl(dns_c_ctx_t *cctx, dns_aclconfctx_t *actx, isc_mem_t *mctx,
             isc_result_t (*getcacl)(dns_c_ctx_t *, dns_c_ipmatchlist_t **),
             dns_acl_t **aclp)
{
    isc_result_t result = ISC_R_SUCCESS;
    dns_c_ipmatchlist_t *cacl = NULL;
    if (*aclp != NULL)
        dns_acl_detach(aclp);
    (void) (*getcacl)(cctx, &cacl);
    if (cacl != NULL) {
        result = dns_acl_fromconfig(cacl, cctx, actx, mctx, aclp);
        dns_c_ipmatchlist_detach(&cacl);
    }
    return (result);
}

/*
 * Configure a single server quota.
 */
static void
configure_server_quota(dns_c_ctx_t *cctx,
               isc_result_t (*getquota)(dns_c_ctx_t *, isc_int32_t *),
               isc_quota_t *quota, int defaultvalue)
{
    isc_int32_t val = defaultvalue;
    (void)(*getquota)(cctx, &val);
    quota->max = val;
}

static isc_result_t
configure_server_querysource(dns_c_ctx_t *cctx, ns_server_t *server,
                 dns_dispatch_t **dispatchp) {
    isc_result_t result;
    struct in_addr ina;
    isc_sockaddr_t sa, any;
    isc_socket_t *socket;

    ina.s_addr = htonl(INADDR_ANY);
    isc_sockaddr_fromin(&any, &ina, 0);

    *dispatchp = NULL;

    if (dns_c_ctx_getquerysource(cctx, &sa) != ISC_R_SUCCESS)
        sa = any;

    /*
     * XXX  We need to have separate query source options for v4 and v6,
     *      but right now we only have one option, and the parser allows
     *      v6 addresses for it.  Until we have a separate v6 option,
     *      make sure that the query source is v4.
     */
    if (isc_sockaddr_pf(&sa) != PF_INET)
        return (DNS_R_NOTIMPLEMENTED);

    /*
     * If we don't support IPv4, we're done!
     */
    if (isc_net_probeipv4() != ISC_R_SUCCESS)
        return (ISC_R_SUCCESS);

    if (isc_sockaddr_equal(&sa, &any)) {
        /*
         * The query source is fully wild.  No special dispatcher
         * work needs to be done.
         */
        return (ISC_R_SUCCESS);
    }

    /*
     * If the interface manager has a dispatcher for this address,
     * use it.
     */
    if (ns_interfacemgr_findudpdispatcher(server->interfacemgr, &sa,
                          dispatchp) !=
        ISC_R_SUCCESS) {
        /*
         * The interface manager doesn't have a matching dispatcher.
         */
        if (server->querysrc_dispatch != NULL) {
            /*
             * We've already got a custom dispatcher.  If it is
             * compatible with the new configuration, use it.
             */
            if (isc_sockaddr_equal(&server->querysrc_address,
                           &sa)) {
                dns_dispatch_attach(server->querysrc_dispatch,
                            dispatchp);
                return (ISC_R_SUCCESS);
            }
            /*
             * The existing custom dispatcher is not compatible.
             * We don't need it anymore.
             */
            dns_dispatch_detach(&server->querysrc_dispatch);
        }
        /*
         * Create a custom dispatcher.
         */
        INSIST(server->querysrc_dispatch == NULL);
        server->querysrc_address = sa;
        socket = NULL;
        result = isc_socket_create(ns_g_socketmgr, AF_INET,
                       isc_sockettype_udp,
                       &socket);
        if (result != ISC_R_SUCCESS)
            return (result);
        result = isc_socket_bind(socket, &sa);
        if (result != ISC_R_SUCCESS) {
            isc_socket_detach(&socket);
            return (result);
        }
        result = dns_dispatch_create(ns_g_mctx, socket,
                         server->task, 4096,
                         1000, 32768, 16411, 16433, NULL,
                         &server->querysrc_dispatch);
        /*
         * Regardless of whether dns_dispatch_create() succeeded or
         * failed, we don't need to keep the reference to the socket.
         */
        isc_socket_detach(&socket);
        if (result != ISC_R_SUCCESS)
            return (result);
        dns_dispatch_attach(server->querysrc_dispatch, dispatchp);
    } else {
        /*
         * We're sharing a UDP dispatcher with the interface manager
         * now.  Any prior custom dispatcher can be discarded.
         */
        if (server->querysrc_dispatch != NULL)
            dns_dispatch_detach(&server->querysrc_dispatch);
    }

    return (ISC_R_SUCCESS);
}

/*
 * This function is called as soon as the 'options' statement has been
 * parsed.
 */
static isc_result_t
options_callback(dns_c_ctx_t *cctx, void *uap) {
    isc_result_t result;

    UNUSED(uap);

    /*
     * Change directory.
     */
    if (cctx->options != NULL &&
        cctx->options->directory != NULL) {
        result = isc_dir_chdir(cctx->options->directory);
        if (result != ISC_R_SUCCESS) {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER,
                      ISC_LOG_ERROR, "change directory "
                      "to '%s' failed: %s",
                      cctx->options->directory,
                      isc_result_totext(result));
            return (result);
        }
    }

    return (ISC_R_SUCCESS);
}

static isc_result_t
load_configuration(const char *filename, ns_server_t *server,
           isc_boolean_t first_time)
{
    isc_result_t result;
    ns_load_t lctx;
    dns_c_cbks_t callbacks;
    dns_c_ctx_t *configctx;
    dns_view_t *view, *view_next;
    dns_viewlist_t tmpviewlist;
    dns_aclconfctx_t aclconfctx;
    dns_dispatch_t *dispatch;
    char *pidfilename;

    dns_aclconfctx_init(&aclconfctx);

    RWLOCK(&server->conflock, isc_rwlocktype_write);
    dns_zonemgr_lockconf(server->zonemgr, isc_rwlocktype_write);

    lctx.mctx = ns_g_mctx;
    lctx.aclconf = &aclconfctx;
    ISC_LIST_INIT(lctx.viewlist);

    callbacks.zonecbk = configure_zone;
    callbacks.zonecbkuap = &lctx;
    callbacks.optscbk = options_callback;
    callbacks.optscbkuap = NULL;

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "loading configuration from '%s'",
              filename);

    /*
     * Parse the configuration file creating a parse tree.  Any
     * 'zone' statements are handled immediately by calling
     * configure_zone() through 'callbacks'.
     */
    configctx = NULL;
    CHECK(dns_c_parse_namedconf(filename, ns_g_mctx, &configctx,
                    &callbacks));

    /*
     * Configure various server options.
     */
    (void) dns_c_ctx_getrecursion(configctx, &server->recursion);
    (void) dns_c_ctx_getauthnxdomain(configctx, &server->auth_nxdomain);
    (void) dns_c_ctx_gettransferformat(configctx,
                       &server->transfer_format);

    CHECK(configure_server_acl(configctx, &aclconfctx, ns_g_mctx,
                   dns_c_ctx_getqueryacl, &server->queryacl));

    CHECK(configure_server_acl(configctx, &aclconfctx, ns_g_mctx,
                   dns_c_ctx_getrecursionacl,
                   &server->recursionacl));

    CHECK(configure_server_acl(configctx, &aclconfctx, ns_g_mctx,
                   dns_c_ctx_gettransferacl,
                   &server->transferacl));

    configure_server_quota(configctx, dns_c_ctx_gettransfersout,
                     &server->xfroutquota, 10);
    configure_server_quota(configctx, dns_c_ctx_gettcpclients,
                     &server->tcpquota, 100);
    configure_server_quota(configctx, dns_c_ctx_getrecursiveclients,
                     &server->recursionquota, 100);

    /*
     * Configure the interface manager according to the "listen-on"
     * statement.
     */
    {
        dns_c_lstnlist_t *clistenon = NULL;
        ns_listenlist_t *listenon = NULL;

        (void) dns_c_ctx_getlistenlist(configctx, &clistenon);
        if (clistenon != NULL) {
            result = ns_listenlist_fromconfig(clistenon,
                              configctx,
                              &aclconfctx,
                              ns_g_mctx,
                              &listenon);
        } else {
            /* Not specified, use default. */
            CHECK(ns_listenlist_default(ns_g_mctx, ns_g_port,
                            &listenon));
        }
        ns_interfacemgr_setlistenon(server->interfacemgr, listenon);
        ns_listenlist_detach(&listenon);
    }

    /*
     * Rescan the interface list to pick up changes in the
     * listen-on option.  It's important that we do this before we try
     * to configure the query source, since the dispatcher we use might
     * be shared with an interface.
     */
    ns_interfacemgr_scan(server->interfacemgr);
    dns_aclenv_copy(&server->aclenv,
            ns_interfacemgr_getaclenv(server->interfacemgr));


    dispatch = NULL;
    CHECK(configure_server_querysource(configctx, server, &dispatch));

    /*
     * If we haven't created any views, create a default view for class
     * IN.  (We're a caching-only server.)
     */
    if (ISC_LIST_EMPTY(lctx.viewlist)) {
        view = NULL;
        CHECKM(dns_view_create(ns_g_mctx, dns_rdataclass_in,
                       "_default", &view),
               "creating default view");
        ISC_LIST_APPEND(lctx.viewlist, view, link);
    }

    /*
     * Configure and freeze the views.  Their zone tables have
     * already been filled in at parsing time, but other stuff
     * like the resolvers are still unconfigured.
     */
    for (view = ISC_LIST_HEAD(lctx.viewlist);
         view != NULL;
         view = ISC_LIST_NEXT(view, link))
    {
        CHECK(configure_view(view, configctx, ns_g_mctx, dispatch));
        dns_view_freeze(view);
    }

    /*
     * We don't need dispatch anymore.
     */
    if (dispatch != NULL)
        dns_dispatch_detach(&dispatch);

    /*
     * Create (or recreate) the version view.
     */
    view = NULL;
    CHECK(create_version_view(configctx, &view));
    ISC_LIST_APPEND(lctx.viewlist, view, link);
    view = NULL;

    /*
     * Swap our new view list with the production one.
     */
    tmpviewlist = server->viewlist;
    server->viewlist = lctx.viewlist;
    lctx.viewlist = tmpviewlist;

    /*
     * Load the TKEY information from the configuration.
     */
    {
        dns_tkey_ctx_t *t = NULL;
        CHECKM(dns_tkeyctx_fromconfig(configctx, ns_g_mctx, &t),
               "configuring TKEY");
        if (server->tkeyctx != NULL)
            dns_tkeyctx_destroy(&server->tkeyctx);
        server->tkeyctx = t;
    }

    if (first_time)
        ns_os_changeuser(ns_g_username);

    if (dns_c_ctx_getpidfilename(configctx, &pidfilename) ==
        ISC_R_NOTFOUND)
        pidfilename = ns_g_defaultpidfile;
    ns_os_writepidfile(pidfilename);

    dns_aclconfctx_destroy(&aclconfctx);

    dns_c_ctx_delete(&configctx);

 cleanup:
    /*
     * This cleans up either the old production view list
     * or our temporary list depending on whether they
     * were swapped above or not.
     */
    for (view = ISC_LIST_HEAD(lctx.viewlist);
         view != NULL;
         view = view_next) {
        view_next = ISC_LIST_NEXT(view, link);
        ISC_LIST_UNLINK(lctx.viewlist, view, link);
        dns_view_detach(&view);

    }

    dns_zonemgr_unlockconf(server->zonemgr, isc_rwlocktype_write);
    RWUNLOCK(&server->conflock, isc_rwlocktype_write);
    return (result);
}

static isc_result_t
load_zones(ns_server_t *server, isc_boolean_t stop) {
    isc_result_t result;
    dns_view_t *view;

    dns_zonemgr_lockconf(server->zonemgr, isc_rwlocktype_read);

    /*
     * Load zone data from disk.
     */
    for (view = ISC_LIST_HEAD(server->viewlist);
         view != NULL;
         view = ISC_LIST_NEXT(view, link))
    {
        CHECK(dns_view_load(view, stop));
    }

    /*
     * Force zone maintenance.  Do this after loading
     * so that we know when we need to force AXFR of
     * slave zones whose master files are missing.
     */
    CHECK(dns_zonemgr_forcemaint(server->zonemgr));
 cleanup:
    dns_zonemgr_unlockconf(server->zonemgr, isc_rwlocktype_read);
    return (result);
}

static void
run_server(isc_task_t *task, isc_event_t *event) {
    isc_result_t result;
    ns_server_t *server = (ns_server_t *) event->arg;

    UNUSED(task);

    isc_event_free(&event);

    CHECKFATAL(ns_clientmgr_create(ns_g_mctx, ns_g_taskmgr, ns_g_timermgr,
                       &server->clientmgr),
           "creating client manager");

    CHECKFATAL(ns_interfacemgr_create(ns_g_mctx, ns_g_taskmgr,
                      ns_g_socketmgr, server->clientmgr,
                      &server->interfacemgr),
           "creating interface manager");

    CHECKFATAL(load_configuration(ns_g_conffile, server, ISC_TRUE),
           "loading configuration");

    CHECKFATAL(load_zones(server, ISC_TRUE),
           "loading zones");

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "running");
}

static void
shutdown_server(isc_task_t *task, isc_event_t *event) {
    dns_view_t *view, *view_next;
    ns_server_t *server = (ns_server_t *) event->arg;

    UNUSED(task);

    RWLOCK(&server->conflock, isc_rwlocktype_write);

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "shutting down");

    for (view = ISC_LIST_HEAD(server->viewlist);
         view != NULL;
         view = view_next) {
        view_next = ISC_LIST_NEXT(view, link);
        ISC_LIST_UNLINK(server->viewlist, view, link);
        dns_view_detach(&view);
    }

    if (server->querysrc_dispatch != NULL)
        dns_dispatch_detach(&server->querysrc_dispatch);
    ns_clientmgr_destroy(&server->clientmgr);
    ns_interfacemgr_shutdown(server->interfacemgr);
    ns_interfacemgr_detach(&server->interfacemgr);
    dns_zonemgr_shutdown(server->zonemgr);

    isc_task_detach(&server->task);

    isc_event_free(&event);

    RWUNLOCK(&server->conflock, isc_rwlocktype_write);
}

void
ns_server_create(isc_mem_t *mctx, ns_server_t **serverp) {
    isc_result_t result;

    ns_server_t *server = isc_mem_get(mctx, sizeof(*server));
    if (server == NULL)
        fatal("allocating server object", ISC_R_NOMEMORY);

    server->mctx = mctx;
    server->task = NULL;

    CHECKFATAL(isc_rwlock_init(&server->conflock, 1, 1),
           "initializing server configuration lock");

    /* Initialize configuration data with default values. */
    server->recursion = ISC_TRUE;
    server->auth_nxdomain = ISC_FALSE; /* Was true in BIND 8 */
    server->transfer_format = dns_one_answer;

    server->queryacl = NULL;
    server->recursionacl = NULL;
    server->transferacl = NULL;

    result = isc_quota_init(&server->xfroutquota, 10);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);
    result = isc_quota_init(&server->tcpquota, 10);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);
    result = isc_quota_init(&server->recursionquota, 100);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);

    result = dns_aclenv_init(mctx, &server->aclenv);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);

    /* Initialize server data structures. */
    server->zonemgr = NULL;
    server->clientmgr = NULL;
    server->interfacemgr = NULL;
    ISC_LIST_INIT(server->viewlist);
    server->roothints = NULL;

    CHECKFATAL(dns_rootns_create(mctx, dns_rdataclass_in, NULL,
                     &server->roothints),
           "setting up root hints");

    CHECKFATAL(isc_mutex_init(&server->reload_event_lock),
           "initializing reload event lock");
    server->reload_event =
        isc_event_allocate(ns_g_mctx, server,
                   NS_EVENT_RELOAD,
                   ns_server_reload,
                   server,
                   sizeof(isc_event_t));
    CHECKFATAL(server->reload_event == NULL ?
           ISC_R_NOMEMORY : ISC_R_SUCCESS,
           "allocating reload event");

    server->tkeyctx = NULL;
    CHECKFATAL(dns_tkeyctx_create(ns_g_mctx, &server->tkeyctx),
           "creating TKEY context");
    server->querysrc_dispatch = NULL;

    /*
     * Setup the server task, which is responsible for coordinating
     * startup and shutdown of the server.
     */
    CHECKFATAL(isc_task_create(ns_g_taskmgr, ns_g_mctx, 0, &server->task),
           "creating server task");
    isc_task_setname(server->task, "server", server);
    CHECKFATAL(isc_task_onshutdown(server->task, shutdown_server, server),
           "isc_task_onshutdown");
    CHECKFATAL(isc_app_onrun(ns_g_mctx, server->task, run_server, server),
           "isc_app_onrun");

    CHECKFATAL(dns_zonemgr_create(ns_g_mctx, ns_g_taskmgr, ns_g_timermgr,
                      ns_g_socketmgr, &server->zonemgr),
           "dns_zonemgr_create");

    server->magic = NS_SERVER_MAGIC;
    *serverp = server;
}

void
ns_server_destroy(ns_server_t **serverp) {
    ns_server_t *server = *serverp;
    REQUIRE(NS_SERVER_VALID(server));

    REQUIRE(server->querysrc_dispatch == NULL);
    if (server->tkeyctx != NULL)
        dns_tkeyctx_destroy(&server->tkeyctx);

    isc_event_free(&server->reload_event);

    INSIST(ISC_LIST_EMPTY(server->viewlist));

    dns_zonemgr_destroy(&server->zonemgr);
    server->zonemgr = NULL;

    dns_db_detach(&server->roothints);

    if (server->queryacl != NULL)
        dns_acl_detach(&server->queryacl);
    if (server->recursionacl != NULL)
        dns_acl_detach(&server->recursionacl);
    if (server->transferacl != NULL)
        dns_acl_detach(&server->transferacl);

    dns_aclenv_destroy(&server->aclenv);

    isc_quota_destroy(&server->recursionquota);
    isc_quota_destroy(&server->tcpquota);
    isc_quota_destroy(&server->xfroutquota);
    isc_rwlock_destroy(&server->conflock);

    server->magic = 0;
    isc_mem_put(server->mctx, server, sizeof(*server));
}

static void
fatal(char *msg, isc_result_t result)
{
    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_CRITICAL, "%s: %s", msg, isc_result_totext(result));
    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_CRITICAL, "exiting (due to fatal error)");
    exit(1);
}

static void
ns_server_reload(isc_task_t *task, isc_event_t *event) {
    isc_result_t result;
    ns_server_t *server = (ns_server_t *) event->arg;
    UNUSED(task);

    result = load_configuration(ns_g_conffile, server, ISC_FALSE);
    if (result != DNS_R_SUCCESS) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "reloading configuration failed: %s",
                  isc_result_totext(result));
    }
    result = load_zones(server, ISC_FALSE);
    if (result != DNS_R_SUCCESS) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "reloading zones failed: %s",
                  isc_result_totext(result));
    }
    LOCK(&server->reload_event_lock);
    INSIST(server->reload_event == NULL);
    server->reload_event = event;
    UNLOCK(&server->reload_event_lock);
}

void
ns_server_reloadwanted(ns_server_t *server) {
    LOCK(&server->reload_event_lock);
    if (server->reload_event != NULL)
        isc_task_send(server->task, &server->reload_event);
    UNLOCK(&server->reload_event_lock);
}

static isc_result_t
ns_listenlist_fromconfig(dns_c_lstnlist_t *clist, dns_c_ctx_t *cctx,
              dns_aclconfctx_t *actx,
              isc_mem_t *mctx, ns_listenlist_t **target)
{
    dns_c_lstnon_t *ce;
    isc_result_t result;
    ns_listenlist_t *dlist = NULL;

    REQUIRE(target != NULL && *target == NULL);

    result = ns_listenlist_create(mctx, &dlist);
    if (result != ISC_R_SUCCESS)
        return (result);

    for (ce = ISC_LIST_HEAD(clist->elements);
         ce != NULL;
         ce = ISC_LIST_NEXT(ce, next))
    {
        ns_listenelt_t *delt = NULL;
        result = ns_listenelt_fromconfig(ce, cctx, actx, mctx, &delt);
        if (result != DNS_R_SUCCESS)
            goto cleanup;
        ISC_LIST_APPEND(dlist->elts, delt, link);
    }
    *target = dlist;
    return (ISC_R_SUCCESS);

 cleanup:
    ns_listenlist_detach(&dlist);
    return (result);
}

/*
 * Create a listen list from the corresponding configuration
 * data structure.
 */
static isc_result_t
ns_listenelt_fromconfig(dns_c_lstnon_t *celt, dns_c_ctx_t *cctx,
             dns_aclconfctx_t *actx,
             isc_mem_t *mctx, ns_listenelt_t **target)
{
    isc_result_t result;
    ns_listenelt_t *delt = NULL;
    REQUIRE(target != NULL && *target == NULL);
    result = ns_listenelt_create(mctx, celt->port, NULL, &delt);
    if (result != ISC_R_SUCCESS)
        return (result);

    result = dns_acl_fromconfig(celt->iml, cctx, actx, mctx, &delt->acl);
    if (result != DNS_R_SUCCESS) {
        ns_listenelt_destroy(delt);
        return (result);
    }
    *target = delt;
    return (ISC_R_SUCCESS);
}