bin/nsupdate/nsupdate.c

	nsupdate.c revision 5eb91bd90e3ad3426e5e3213031556a737cf3809
/*
 * Copyright (C) 2000-2002  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.
 */

/* $Id: nsupdate.c,v 1.122 2003/07/25 00:01:05 marka Exp $ */

#include <config.h>

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>

#include <isc/app.h>
#include <isc/base64.h>
#include <isc/buffer.h>
#include <isc/commandline.h>
#include <isc/entropy.h>
#include <isc/event.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/parseint.h>
#include <isc/region.h>
#include <isc/sockaddr.h>
#include <isc/socket.h>
#include <isc/stdio.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/types.h>
#include <isc/util.h>

#include <dns/callbacks.h>
#include <dns/dispatch.h>
#include <dns/dnssec.h>
#include <dns/events.h>
#include <dns/fixedname.h>
#include <dns/masterdump.h>
#include <dns/message.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/request.h>
#include <dns/result.h>
#include <dns/tsig.h>

#include <dst/dst.h>

#include <lwres/lwres.h>
#include <lwres/net.h>

#include <bind9/getaddresses.h>

#ifdef HAVE_ADDRINFO
#ifdef HAVE_GETADDRINFO
#ifdef HAVE_GAISTRERROR
#define USE_GETADDRINFO
#endif
#endif
#endif

#ifndef USE_GETADDRINFO
#ifndef ISC_PLATFORM_NONSTDHERRNO
extern int h_errno;
#endif
#endif

#define MAXCMD (4 * 1024)
#define MAXWIRE (64 * 1024)
#define PACKETSIZE ((64 * 1024) - 1)
#define INITTEXT (2 * 1024)
#define MAXTEXT (128 * 1024)
#define FIND_TIMEOUT 5
#define TTL_MAX 2147483647U /* Maximum signed 32 bit integer. */

#define DNSDEFAULTPORT 53

#ifndef RESOLV_CONF
#define RESOLV_CONF "/etc/resolv.conf"
#endif

static isc_boolean_t debugging = ISC_FALSE, ddebugging = ISC_FALSE;
static isc_boolean_t memdebugging = ISC_FALSE;
static isc_boolean_t have_ipv4 = ISC_FALSE;
static isc_boolean_t have_ipv6 = ISC_FALSE;
static isc_boolean_t is_dst_up = ISC_FALSE;
static isc_boolean_t usevc = ISC_FALSE;
static isc_taskmgr_t *taskmgr = NULL;
static isc_task_t *global_task = NULL;
static isc_event_t *global_event = NULL;
static isc_mem_t *mctx = NULL;
static dns_dispatchmgr_t *dispatchmgr = NULL;
static dns_requestmgr_t *requestmgr = NULL;
static isc_socketmgr_t *socketmgr = NULL;
static isc_timermgr_t *timermgr = NULL;
static dns_dispatch_t *dispatchv4 = NULL;
static dns_dispatch_t *dispatchv6 = NULL;
static dns_message_t *updatemsg = NULL;
static dns_fixedname_t resolvdomain; /* from resolv.conf's domain line */
static dns_name_t *origin; /* Points to one of above, or dns_rootname */
static dns_fixedname_t fuserzone;
static dns_name_t *userzone = NULL;
static dns_tsigkey_t *tsigkey = NULL;
static dst_key_t *sig0key;
static lwres_context_t *lwctx = NULL;
static lwres_conf_t *lwconf;
static isc_sockaddr_t *servers;
static int ns_inuse = 0;
static int ns_total = 0;
static isc_sockaddr_t *userserver = NULL;
static isc_sockaddr_t *localaddr = NULL;
static char *keystr = NULL, *keyfile = NULL;
static isc_entropy_t *entp = NULL;
static isc_boolean_t shuttingdown = ISC_FALSE;
static FILE *input;
static isc_boolean_t interactive = ISC_TRUE;
static isc_boolean_t seenerror = ISC_FALSE;
static const dns_master_style_t *style;
static int requests = 0;
static unsigned int timeout = 300;
static unsigned int udp_timeout = 3;
static unsigned int udp_retries = 3;

typedef struct nsu_requestinfo {
    dns_message_t *msg;
    isc_sockaddr_t *addr;
} nsu_requestinfo_t;

static void
sendrequest(isc_sockaddr_t *srcaddr, isc_sockaddr_t *destaddr,
        dns_message_t *msg, dns_request_t **request);
static void
fatal(const char *format, ...) ISC_FORMAT_PRINTF(1, 2);

static void
debug(const char *format, ...) ISC_FORMAT_PRINTF(1, 2);

static void
ddebug(const char *format, ...) ISC_FORMAT_PRINTF(1, 2);

#define STATUS_MORE (isc_uint16_t)0
#define STATUS_SEND (isc_uint16_t)1
#define STATUS_QUIT (isc_uint16_t)2
#define STATUS_SYNTAX   (isc_uint16_t)3

static void
fatal(const char *format, ...) {
    va_list args;

    va_start(args, format);
    vfprintf(stderr, format, args);
    va_end(args);
    fprintf(stderr, "\n");
    exit(1);
}

static void
debug(const char *format, ...) {
    va_list args;

    if (debugging) {
        va_start(args, format);
        vfprintf(stderr, format, args);
        va_end(args);
        fprintf(stderr, "\n");
    }
}

static void
ddebug(const char *format, ...) {
    va_list args;

    if (ddebugging) {
        va_start(args, format);
        vfprintf(stderr, format, args);
        va_end(args);
        fprintf(stderr, "\n");
    }
}

static inline void
check_result(isc_result_t result, const char *msg) {
    if (result != ISC_R_SUCCESS)
        fatal("%s: %s", msg, isc_result_totext(result));
}

static void *
mem_alloc(void *arg, size_t size) {
    return (isc_mem_get(arg, size));
}

static void
mem_free(void *arg, void *mem, size_t size) {
    isc_mem_put(arg, mem, size);
}

static char *
nsu_strsep(char **stringp, const char *delim) {
    char *string = *stringp;
    char *s;
    const char *d;
    char sc, dc;

    if (string == NULL)
        return (NULL);

    for (; *string != '\0'; string++) {
        sc = *string;
        for (d = delim; (dc = *d) != '\0'; d++) {
            if (sc == dc)
                break;
        }
        if (dc == 0)
            break;
    }

    for (s = string; *s != '\0'; s++) {
        sc = *s;
        for (d = delim; (dc = *d) != '\0'; d++) {
            if (sc == dc) {
                *s++ = '\0';
                *stringp = s;
                return (string);
            }
        }
    }
    *stringp = NULL;
    return (string);
}

static unsigned int
count_dots(char *s, isc_boolean_t *last_was_dot) {
    int i = 0;
    *last_was_dot = ISC_FALSE;
    while (*s != 0) {
        if (*s++ == '.') {
            i++;
            *last_was_dot = ISC_TRUE;
        } else
            *last_was_dot = ISC_FALSE;
    }
    return (i);
}

static void
reset_system(void) {
    isc_result_t result;

    ddebug("reset_system()");
    /* If the update message is still around, destroy it */
    if (updatemsg != NULL)
        dns_message_reset(updatemsg, DNS_MESSAGE_INTENTRENDER);
    else {
        result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
                        &updatemsg);
        check_result(result, "dns_message_create");
    }
    updatemsg->opcode = dns_opcode_update;
}

static void
setup_keystr(void) {
    unsigned char *secret = NULL;
    int secretlen;
    isc_buffer_t secretbuf;
    isc_result_t result;
    isc_buffer_t keynamesrc;
    char *secretstr;
    char *s;
    dns_fixedname_t fkeyname;
    dns_name_t *keyname;

    dns_fixedname_init(&fkeyname);
    keyname = dns_fixedname_name(&fkeyname);

    debug("Creating key...");

    s = strchr(keystr, ':');
    if (s == NULL || s == keystr || *s == 0)
        fatal("key option must specify keyname:secret");
    secretstr = s + 1;

    isc_buffer_init(&keynamesrc, keystr, s - keystr);
    isc_buffer_add(&keynamesrc, s - keystr);

    debug("namefromtext");
    result = dns_name_fromtext(keyname, &keynamesrc, dns_rootname,
                   ISC_FALSE, NULL);
    check_result(result, "dns_name_fromtext");

    secretlen = strlen(secretstr) * 3 / 4;
    secret = isc_mem_allocate(mctx, secretlen);
    if (secret == NULL)
        fatal("out of memory");

    isc_buffer_init(&secretbuf, secret, secretlen);
    result = isc_base64_decodestring(secretstr, &secretbuf);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not create key from %s: %s\n",
            keystr, isc_result_totext(result));
        goto failure;
    }

    secretlen = isc_buffer_usedlength(&secretbuf);

    debug("keycreate");
    result = dns_tsigkey_create(keyname, dns_tsig_hmacmd5_name,
                    secret, secretlen, ISC_TRUE, NULL,
                    0, 0, mctx, NULL, &tsigkey);
    if (result != ISC_R_SUCCESS)
        fprintf(stderr, "could not create key from %s: %s\n",
            keystr, dns_result_totext(result));
 failure:
    if (secret != NULL)
        isc_mem_free(mctx, secret);
}

static void
setup_keyfile(void) {
    dst_key_t *dstkey = NULL;
    isc_result_t result;

    debug("Creating key...");

    result = dst_key_fromnamedfile(keyfile, DST_TYPE_PRIVATE, mctx,
                       &dstkey);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not read key from %s: %s\n",
            keyfile, isc_result_totext(result));
        return;
    }
    if (dst_key_alg(dstkey) == DST_ALG_HMACMD5) {
        result = dns_tsigkey_createfromkey(dst_key_name(dstkey),
                           dns_tsig_hmacmd5_name,
                           dstkey, ISC_FALSE, NULL,
                           0, 0, mctx, NULL, &tsigkey);
        if (result != ISC_R_SUCCESS) {
            fprintf(stderr, "could not create key from %s: %s\n",
                keyfile, isc_result_totext(result));
            dst_key_free(&dstkey);
            return;
        }
    } else
        sig0key = dstkey;
}

static void
doshutdown(void) {
    isc_task_detach(&global_task);

    if (userserver != NULL)
        isc_mem_put(mctx, userserver, sizeof(isc_sockaddr_t));

    if (localaddr != NULL)
        isc_mem_put(mctx, localaddr, sizeof(isc_sockaddr_t));

    if (tsigkey != NULL) {
        ddebug("Freeing TSIG key");
        dns_tsigkey_detach(&tsigkey);
    }

    if (sig0key != NULL) {
        ddebug("Freeing SIG(0) key");
        dst_key_free(&sig0key);
    }

    if (updatemsg != NULL)
        dns_message_destroy(&updatemsg);

    if (is_dst_up) {
        ddebug("Destroy DST lib");
        dst_lib_destroy();
        is_dst_up = ISC_FALSE;
    }

    if (entp != NULL) {
        ddebug("Detach from entropy");
        isc_entropy_detach(&entp);
    }

    lwres_conf_clear(lwctx);
    lwres_context_destroy(&lwctx);

    isc_mem_put(mctx, servers, ns_total * sizeof(isc_sockaddr_t));

    ddebug("Destroying request manager");
    dns_requestmgr_detach(&requestmgr);

    ddebug("Freeing the dispatchers");
    if (have_ipv4)
        dns_dispatch_detach(&dispatchv4);
    if (have_ipv6)
        dns_dispatch_detach(&dispatchv6);

    ddebug("Shutting down dispatch manager");
    dns_dispatchmgr_destroy(&dispatchmgr);

}

static void
maybeshutdown(void) {
    ddebug("Shutting down request manager");
    dns_requestmgr_shutdown(requestmgr);

    if (requests != 0)
        return;

    doshutdown();
}

static void
shutdown_program(isc_task_t *task, isc_event_t *event) {
    REQUIRE(task == global_task);
    UNUSED(task);

    ddebug("shutdown_program()");
    isc_event_free(&event);

    shuttingdown = ISC_TRUE;
    maybeshutdown();
}

static void
setup_system(void) {
    isc_result_t result;
    isc_sockaddr_t bind_any, bind_any6;
    isc_buffer_t buf;
    lwres_result_t lwresult;
    unsigned int attrs, attrmask;
    int i;

    ddebug("setup_system()");

    dns_result_register();

    result = isc_net_probeipv4();
    if (result == ISC_R_SUCCESS)
        have_ipv4 = ISC_TRUE;

    result = isc_net_probeipv6();
    if (result == ISC_R_SUCCESS)
        have_ipv6 = ISC_TRUE;

    if (!have_ipv4 && !have_ipv6)
        fatal("could not find either IPv4 or IPv6");

    result = isc_mem_create(0, 0, &mctx);
    check_result(result, "isc_mem_create");

    lwresult = lwres_context_create(&lwctx, mctx, mem_alloc, mem_free, 1);
    if (lwresult != LWRES_R_SUCCESS)
        fatal("lwres_context_create failed");

    (void)lwres_conf_parse(lwctx, RESOLV_CONF);
    lwconf = lwres_conf_get(lwctx);

    ns_total = lwconf->nsnext;
    if (ns_total <= 0) {
        /* No name servers in resolv.conf; default to loopback. */
        struct in_addr localhost;
        ns_total = 1;
        servers = isc_mem_get(mctx, ns_total * sizeof(isc_sockaddr_t));
        if (servers == NULL)
            fatal("out of memory");
        localhost.s_addr = htonl(INADDR_LOOPBACK);
        isc_sockaddr_fromin(&servers[0], &localhost, DNSDEFAULTPORT);
    } else {
        servers = isc_mem_get(mctx, ns_total * sizeof(isc_sockaddr_t));
        if (servers == NULL)
            fatal("out of memory");
        for (i = 0; i < ns_total; i++) {
            if (lwconf->nameservers[i].family == LWRES_ADDRTYPE_V4) {
                struct in_addr in4;
                memcpy(&in4, lwconf->nameservers[i].address, 4);
                isc_sockaddr_fromin(&servers[i], &in4, DNSDEFAULTPORT);
            } else {
                struct in6_addr in6;
                memcpy(&in6, lwconf->nameservers[i].address, 16);
                isc_sockaddr_fromin6(&servers[i], &in6,
                             DNSDEFAULTPORT);
            }
        }
    }

    result = isc_entropy_create(mctx, &entp);
    check_result(result, "isc_entropy_create");

    result = dns_dispatchmgr_create(mctx, entp, &dispatchmgr);
    check_result(result, "dns_dispatchmgr_create");

    result = isc_socketmgr_create(mctx, &socketmgr);
    check_result(result, "dns_socketmgr_create");

    result = isc_timermgr_create(mctx, &timermgr);
    check_result(result, "dns_timermgr_create");

    result = isc_taskmgr_create(mctx, 1, 0, &taskmgr);
    check_result(result, "isc_taskmgr_create");

    result = isc_task_create(taskmgr, 0, &global_task);
    check_result(result, "isc_task_create");

    result = isc_task_onshutdown(global_task, shutdown_program, NULL);
    check_result(result, "isc_task_onshutdown");

    result = dst_lib_init(mctx, entp, 0);
    check_result(result, "dst_lib_init");
    is_dst_up = ISC_TRUE;

    attrmask = DNS_DISPATCHATTR_UDP | DNS_DISPATCHATTR_TCP;
    attrmask |= DNS_DISPATCHATTR_IPV4 | DNS_DISPATCHATTR_IPV6;

    if (have_ipv6) {
        attrs = DNS_DISPATCHATTR_UDP;
        attrs |= DNS_DISPATCHATTR_MAKEQUERY;
        attrs |= DNS_DISPATCHATTR_IPV6;
        isc_sockaddr_any6(&bind_any6);
        result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
                         &bind_any6, PACKETSIZE,
                         4, 2, 3, 5,
                         attrs, attrmask, &dispatchv6);
        check_result(result, "dns_dispatch_getudp (v6)");
    }

    if (have_ipv4) {
        attrs = DNS_DISPATCHATTR_UDP;
        attrs |= DNS_DISPATCHATTR_MAKEQUERY;
        attrs |= DNS_DISPATCHATTR_IPV4;
        isc_sockaddr_any(&bind_any);
        result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
                         &bind_any, PACKETSIZE,
                         4, 2, 3, 5,
                         attrs, attrmask, &dispatchv4);
        check_result(result, "dns_dispatch_getudp (v4)");
    }

    result = dns_requestmgr_create(mctx, timermgr,
                       socketmgr, taskmgr, dispatchmgr,
                       dispatchv4, dispatchv6, &requestmgr);
    check_result(result, "dns_requestmgr_create");

    if (lwconf->domainname != NULL) {
        dns_fixedname_init(&resolvdomain);
        isc_buffer_init(&buf, lwconf->domainname,
                strlen(lwconf->domainname));
        isc_buffer_add(&buf, strlen(lwconf->domainname));
        result = dns_name_fromtext(dns_fixedname_name(&resolvdomain),
                       &buf, dns_rootname, ISC_FALSE,
                       NULL);
        check_result(result, "dns_name_fromtext");
        origin = dns_fixedname_name(&resolvdomain);
    }
    else
        origin = dns_rootname;

    if (keystr != NULL)
        setup_keystr();
    else if (keyfile != NULL)
        setup_keyfile();
}

static void
get_address(char *host, in_port_t port, isc_sockaddr_t *sockaddr) {
    int count;
    isc_result_t result;

    isc_app_block();
    result = bind9_getaddresses(host, port, sockaddr, 1, &count);
    isc_app_unblock();
    if (result != ISC_R_SUCCESS)
        fatal("couldn't get address for '%s': %s",
              host, isc_result_totext(result));
    INSIST(count == 1);
}

static void
parse_args(int argc, char **argv) {
    int ch;
    isc_result_t result;

    debug("parse_args");
    while ((ch = isc_commandline_parse(argc, argv, "dDMy:vk:r:t:u:")) != -1)
    {
        switch (ch) {
        case 'd':
            debugging = ISC_TRUE;
            break;
        case 'D': /* was -dd */
            debugging = ISC_TRUE;
            ddebugging = ISC_TRUE;
            break;
        case 'M': /* was -dm */
            debugging = ISC_TRUE;
            ddebugging = ISC_TRUE;
            memdebugging = ISC_TRUE;
            isc_mem_debugging = ISC_MEM_DEBUGTRACE |
                        ISC_MEM_DEBUGRECORD;
            break;
        case 'y':
            keystr = isc_commandline_argument;
            break;
        case 'v':
            usevc = ISC_TRUE;
            break;
        case 'k':
            keyfile = isc_commandline_argument;
            break;
        case 't':
            result = isc_parse_uint32(&timeout,
                          isc_commandline_argument, 10);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "bad timeout '%s'\n",                       isc_commandline_argument);
                exit(1);
            }
            if (timeout == 0)
                timeout = ULONG_MAX;
            break;
        case 'u':
            result = isc_parse_uint32(&udp_timeout,
                          isc_commandline_argument, 10);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "bad udp timeout '%s'\n",                       isc_commandline_argument);
                exit(1);
            }
            if (udp_timeout == 0)
                udp_timeout = ULONG_MAX;
            break;
        case 'r':
            result = isc_parse_uint32(&udp_retries,
                          isc_commandline_argument, 10);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "bad udp retries '%s'\n",                       isc_commandline_argument);
                exit(1);
            }
            break;
        default:
            fprintf(stderr, "%s: invalid argument -%c\n",
                argv[0], ch);
            fprintf(stderr, "usage: nsupdate [-d] "
                "[-y keyname:secret | -k keyfile] [-v] "
                "[filename]\n");
            exit(1);
        }
    }
    if (keyfile != NULL && keystr != NULL) {
        fprintf(stderr, "%s: cannot specify both -k and -y\n",
            argv[0]);
        exit(1);
    }

    if (argv[isc_commandline_index] != NULL) {
        if (strcmp(argv[isc_commandline_index], "-") == 0) {
            input = stdin;
        } else {
            result = isc_stdio_open(argv[isc_commandline_index],
                        "r", &input);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "could not open '%s': %s\n",
                    argv[isc_commandline_index],
                    isc_result_totext(result));
                exit(1);
            }
        }
        interactive = ISC_FALSE;
    }
}

static isc_uint16_t
parse_name(char **cmdlinep, dns_message_t *msg, dns_name_t **namep) {
    isc_result_t result;
    char *word;
    isc_buffer_t *namebuf = NULL;
    isc_buffer_t source;
    unsigned int dots;
    isc_boolean_t last;
    dns_name_t *rn;

    word = nsu_strsep(cmdlinep, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read owner name\n");
        return (STATUS_SYNTAX);
    }

    result = dns_message_gettempname(msg, namep);
    check_result(result, "dns_message_gettempname");
    result = isc_buffer_allocate(mctx, &namebuf, DNS_NAME_MAXWIRE);
    check_result(result, "isc_buffer_allocate");
    dns_name_init(*namep, NULL);
    dns_name_setbuffer(*namep, namebuf);
    dns_message_takebuffer(msg, &namebuf);
    isc_buffer_init(&source, word, strlen(word));
    isc_buffer_add(&source, strlen(word));
    dots = count_dots(word, &last);
    if (dots > lwconf->ndots || last)
        rn = dns_rootname;
    else if (userzone != NULL)
        rn = userzone;
    else
        rn = origin;
    result = dns_name_fromtext(*namep, &source, rn,
                   ISC_FALSE, NULL);
    check_result(result, "dns_name_fromtext");
    isc_buffer_invalidate(&source);
    return (STATUS_MORE);
}

static isc_uint16_t
parse_rdata(char **cmdlinep, dns_rdataclass_t rdataclass,
        dns_rdatatype_t rdatatype, dns_message_t *msg,
        dns_rdata_t *rdata)
{
    char *cmdline = *cmdlinep;
    isc_buffer_t source, *buf = NULL, *newbuf = NULL;
    isc_region_t r;
    isc_lex_t *lex = NULL;
    dns_rdatacallbacks_t callbacks;
    isc_result_t result;
    dns_name_t *rn;

    while (*cmdline != 0 && isspace((unsigned char)*cmdline))
        cmdline++;

    if (*cmdline != 0) {
        dns_rdatacallbacks_init(&callbacks);
        if (userzone != NULL)
            rn = userzone;
        else
            rn = origin;
        result = isc_lex_create(mctx, strlen(cmdline), &lex);
        check_result(result, "isc_lex_create");
        isc_buffer_init(&source, cmdline, strlen(cmdline));
        isc_buffer_add(&source, strlen(cmdline));
        result = isc_lex_openbuffer(lex, &source);
        check_result(result, "isc_lex_openbuffer");
        result = isc_buffer_allocate(mctx, &buf, MAXWIRE);
        check_result(result, "isc_buffer_allocate");
        result = dns_rdata_fromtext(rdata, rdataclass, rdatatype, lex,
                        rn, ISC_FALSE, mctx, buf,
                        &callbacks);
        isc_lex_destroy(&lex);
        if (result == ISC_R_SUCCESS) {
            isc_buffer_usedregion(buf, &r);
            result = isc_buffer_allocate(mctx, &newbuf, r.length);
            check_result(result, "isc_buffer_allocate");
            isc_buffer_putmem(newbuf, r.base, r.length);
            isc_buffer_usedregion(newbuf, &r);
            dns_rdata_fromregion(rdata, rdataclass, rdatatype, &r);
            isc_buffer_free(&buf);
            dns_message_takebuffer(msg, &newbuf);
        } else {
            fprintf(stderr, "invalid rdata format: %s\n",
                isc_result_totext(result));
            isc_buffer_free(&buf);
            return (STATUS_SYNTAX);
        }
    } else {
        rdata->flags = DNS_RDATA_UPDATE;
    }
    *cmdlinep = cmdline;
    return (STATUS_MORE);
}

static isc_uint16_t
make_prereq(char *cmdline, isc_boolean_t ispositive, isc_boolean_t isrrset) {
    isc_result_t result;
    char *word;
    dns_name_t *name = NULL;
    isc_textregion_t region;
    dns_rdataset_t *rdataset = NULL;
    dns_rdatalist_t *rdatalist = NULL;
    dns_rdataclass_t rdataclass;
    dns_rdatatype_t rdatatype;
    dns_rdata_t *rdata = NULL;
    isc_uint16_t retval;

    ddebug("make_prereq()");

    /*
     * Read the owner name
     */
    retval = parse_name(&cmdline, updatemsg, &name);
    if (retval != STATUS_MORE)
        return (retval);

    /*
     * If this is an rrset prereq, read the class or type.
     */
    if (isrrset) {
        word = nsu_strsep(&cmdline, " \t\r\n");
        if (*word == 0) {
            fprintf(stderr, "could not read class or type\n");
            goto failure;
        }
        region.base = word;
        region.length = strlen(word);
        result = dns_rdataclass_fromtext(&rdataclass, &region);
        if (result == ISC_R_SUCCESS) {
            /*
             * Now read the type.
             */
            word = nsu_strsep(&cmdline, " \t\r\n");
            if (*word == 0) {
                fprintf(stderr, "could not read type\n");
                goto failure;
            }
            region.base = word;
            region.length = strlen(word);
            result = dns_rdatatype_fromtext(&rdatatype, &region);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "invalid type: %s\n", word);
                goto failure;
            }
        } else {
            rdataclass = dns_rdataclass_in;
            result = dns_rdatatype_fromtext(&rdatatype, &region);
            if (result != ISC_R_SUCCESS) {
                fprintf(stderr, "invalid type: %s\n", word);
                goto failure;
            }
        }
    } else
        rdatatype = dns_rdatatype_any;

    result = dns_message_gettemprdata(updatemsg, &rdata);
    check_result(result, "dns_message_gettemprdata");

    rdata->data = NULL;
    rdata->length = 0;

    if (isrrset && ispositive) {
        retval = parse_rdata(&cmdline, rdataclass, rdatatype,
                     updatemsg, rdata);
        if (retval != STATUS_MORE)
            goto failure;
    } else
        rdata->flags = DNS_RDATA_UPDATE;

    result = dns_message_gettemprdatalist(updatemsg, &rdatalist);
    check_result(result, "dns_message_gettemprdatalist");
    result = dns_message_gettemprdataset(updatemsg, &rdataset);
    check_result(result, "dns_message_gettemprdataset");
    dns_rdatalist_init(rdatalist);
    rdatalist->type = rdatatype;
    if (ispositive) {
        if (isrrset && rdata->data != NULL)
            rdatalist->rdclass = rdataclass;
        else
            rdatalist->rdclass = dns_rdataclass_any;
    } else
        rdatalist->rdclass = dns_rdataclass_none;
    rdatalist->covers = 0;
    rdatalist->ttl = 0;
    rdata->rdclass = rdatalist->rdclass;
    rdata->type = rdatatype;
    ISC_LIST_INIT(rdatalist->rdata);
    ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
    dns_rdataset_init(rdataset);
    dns_rdatalist_tordataset(rdatalist, rdataset);
    ISC_LIST_INIT(name->list);
    ISC_LIST_APPEND(name->list, rdataset, link);
    dns_message_addname(updatemsg, name, DNS_SECTION_PREREQUISITE);
    return (STATUS_MORE);

 failure:
    if (name != NULL)
        dns_message_puttempname(updatemsg, &name);
    return (STATUS_SYNTAX);
}

static isc_uint16_t
evaluate_prereq(char *cmdline) {
    char *word;
    isc_boolean_t ispositive, isrrset;

    ddebug("evaluate_prereq()");
    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read operation code\n");
        return (STATUS_SYNTAX);
    }
    if (strcasecmp(word, "nxdomain") == 0) {
        ispositive = ISC_FALSE;
        isrrset = ISC_FALSE;
    } else if (strcasecmp(word, "yxdomain") == 0) {
        ispositive = ISC_TRUE;
        isrrset = ISC_FALSE;
    } else if (strcasecmp(word, "nxrrset") == 0) {
        ispositive = ISC_FALSE;
        isrrset = ISC_TRUE;
    } else if (strcasecmp(word, "yxrrset") == 0) {
        ispositive = ISC_TRUE;
        isrrset = ISC_TRUE;
    } else {
        fprintf(stderr, "incorrect operation code: %s\n", word);
        return (STATUS_SYNTAX);
    }
    return (make_prereq(cmdline, ispositive, isrrset));
}

static isc_uint16_t
evaluate_server(char *cmdline) {
    char *word, *server;
    long port;

    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read server name\n");
        return (STATUS_SYNTAX);
    }
    server = word;

    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0)
        port = DNSDEFAULTPORT;
    else {
        char *endp;
        port = strtol(word, &endp, 10);
        if (*endp != 0) {
            fprintf(stderr, "port '%s' is not numeric\n", word);
            return (STATUS_SYNTAX);
        } else if (port < 1 || port > 65535) {
            fprintf(stderr, "port '%s' is out of range "
                "(1 to 65535)\n", word);
            return (STATUS_SYNTAX);
        }
    }

    if (userserver == NULL) {
        userserver = isc_mem_get(mctx, sizeof(isc_sockaddr_t));
        if (userserver == NULL)
            fatal("out of memory");
    }

    get_address(server, (in_port_t)port, userserver);

    return (STATUS_MORE);
}

static isc_uint16_t
evaluate_local(char *cmdline) {
    char *word, *local;
    long port;
    struct in_addr in4;
    struct in6_addr in6;

    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read server name\n");
        return (STATUS_SYNTAX);
    }
    local = word;

    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0)
        port = 0;
    else {
        char *endp;
        port = strtol(word, &endp, 10);
        if (*endp != 0) {
            fprintf(stderr, "port '%s' is not numeric\n", word);
            return (STATUS_SYNTAX);
        } else if (port < 1 || port > 65535) {
            fprintf(stderr, "port '%s' is out of range "
                "(1 to 65535)\n", word);
            return (STATUS_SYNTAX);
        }
    }

    if (localaddr == NULL) {
        localaddr = isc_mem_get(mctx, sizeof(isc_sockaddr_t));
        if (localaddr == NULL)
            fatal("out of memory");
    }

    if (have_ipv6 && inet_pton(AF_INET6, local, &in6) == 1)
        isc_sockaddr_fromin6(localaddr, &in6, (in_port_t)port);
    else if (have_ipv4 && inet_pton(AF_INET, local, &in4) == 1)
        isc_sockaddr_fromin(localaddr, &in4, (in_port_t)port);
    else {
        fprintf(stderr, "invalid address %s", local);
        return (STATUS_SYNTAX);
    }

    return (STATUS_MORE);
}

static isc_uint16_t
evaluate_key(char *cmdline) {
    char *namestr;
    char *secretstr;
    isc_buffer_t b;
    isc_result_t result;
    dns_fixedname_t fkeyname;
    dns_name_t *keyname;
    int secretlen;
    unsigned char *secret = NULL;
    isc_buffer_t secretbuf;

    namestr = nsu_strsep(&cmdline, " \t\r\n");
    if (*namestr == 0) {
        fprintf(stderr, "could not read key name\n");
        return (STATUS_SYNTAX);
    }

    dns_fixedname_init(&fkeyname);
    keyname = dns_fixedname_name(&fkeyname);

    isc_buffer_init(&b, namestr, strlen(namestr));
    isc_buffer_add(&b, strlen(namestr));
    result = dns_name_fromtext(keyname, &b, dns_rootname, ISC_FALSE, NULL);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not parse key name\n");
        return (STATUS_SYNTAX);
    }

    secretstr = nsu_strsep(&cmdline, "\r\n");
    if (*secretstr == 0) {
        fprintf(stderr, "could not read key secret\n");
        return (STATUS_SYNTAX);
    }
    secretlen = strlen(secretstr) * 3 / 4;
    secret = isc_mem_allocate(mctx, secretlen);
    if (secret == NULL)
        fatal("out of memory");

    isc_buffer_init(&secretbuf, secret, secretlen);
    result = isc_base64_decodestring(secretstr, &secretbuf);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not create key from %s: %s\n",
            secretstr, isc_result_totext(result));
        isc_mem_free(mctx, secret);
        return (STATUS_SYNTAX);
    }
    secretlen = isc_buffer_usedlength(&secretbuf);

    if (tsigkey != NULL)
        dns_tsigkey_detach(&tsigkey);
    result = dns_tsigkey_create(keyname, dns_tsig_hmacmd5_name,
                    secret, secretlen, ISC_TRUE, NULL, 0, 0,
                    mctx, NULL, &tsigkey);
    isc_mem_free(mctx, secret);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not create key from %s %s: %s\n",
            namestr, secretstr, dns_result_totext(result));
        return (STATUS_SYNTAX);
    }
    return (STATUS_MORE);
}

static isc_uint16_t
evaluate_zone(char *cmdline) {
    char *word;
    isc_buffer_t b;
    isc_result_t result;

    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read zone name\n");
        return (STATUS_SYNTAX);
    }

    dns_fixedname_init(&fuserzone);
    userzone = dns_fixedname_name(&fuserzone);
    isc_buffer_init(&b, word, strlen(word));
    isc_buffer_add(&b, strlen(word));
    result = dns_name_fromtext(userzone, &b, dns_rootname, ISC_FALSE,
                   NULL);
    if (result != ISC_R_SUCCESS) {
        userzone = NULL; /* Lest it point to an invalid name */
        fprintf(stderr, "could not parse zone name\n");
        return (STATUS_SYNTAX);
    }

    return (STATUS_MORE);
}

static isc_uint16_t
update_addordelete(char *cmdline, isc_boolean_t isdelete) {
    isc_result_t result;
    dns_name_t *name = NULL;
    isc_uint32_t ttl;
    char *word;
    dns_rdataclass_t rdataclass;
    dns_rdatatype_t rdatatype;
    dns_rdata_t *rdata = NULL;
    dns_rdatalist_t *rdatalist = NULL;
    dns_rdataset_t *rdataset = NULL;
    isc_textregion_t region;
    isc_uint16_t retval;

    ddebug("update_addordelete()");

    /*
     * Read the owner name.
     */
    retval = parse_name(&cmdline, updatemsg, &name);
    if (retval != STATUS_MORE)
        return (retval);

    result = dns_message_gettemprdata(updatemsg, &rdata);
    check_result(result, "dns_message_gettemprdata");

    rdata->rdclass = 0;
    rdata->type = 0;
    rdata->data = NULL;
    rdata->length = 0;

    /*
     * If this is an add, read the TTL and verify that it's in range.
     * If it's a delete, ignore a TTL if present (for compatibility).
     */
    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        if (!isdelete) {
            fprintf(stderr, "could not read owner ttl\n");
            goto failure;
        }
        else {
            ttl = 0;
            rdataclass = dns_rdataclass_any;
            rdatatype = dns_rdatatype_any;
            rdata->flags = DNS_RDATA_UPDATE;
            goto doneparsing;
        }
    }
    result = isc_parse_uint32(&ttl, word, 10);
    if (result != ISC_R_SUCCESS) {
        if (isdelete) {
            ttl = 0;
            goto parseclass;
        } else {
            fprintf(stderr, "ttl '%s': %s\n", word,
                isc_result_totext(result));
            goto failure;
        }
    }

    if (isdelete)
        ttl = 0;
    else if (ttl > TTL_MAX) {
        fprintf(stderr, "ttl '%s' is out of range (0 to %u)\n",
            word, TTL_MAX);
        goto failure;
    }

    /*
     * Read the class or type.
     */
    word = nsu_strsep(&cmdline, " \t\r\n");
 parseclass:
    if (*word == 0) {
        if (isdelete) {
            rdataclass = dns_rdataclass_any;
            rdatatype = dns_rdatatype_any;
            rdata->flags = DNS_RDATA_UPDATE;
            goto doneparsing;
        } else {
            fprintf(stderr, "could not read class or type\n");
            goto failure;
        }
    }
    region.base = word;
    region.length = strlen(word);
    result = dns_rdataclass_fromtext(&rdataclass, &region);
    if (result == ISC_R_SUCCESS) {
        /*
         * Now read the type.
         */
        word = nsu_strsep(&cmdline, " \t\r\n");
        if (*word == 0) {
            if (isdelete) {
                rdataclass = dns_rdataclass_any;
                rdatatype = dns_rdatatype_any;
                rdata->flags = DNS_RDATA_UPDATE;
                goto doneparsing;
            } else {
                fprintf(stderr, "could not read type\n");
                goto failure;
            }
        }
        region.base = word;
        region.length = strlen(word);
        result = dns_rdatatype_fromtext(&rdatatype, &region);
        if (result != ISC_R_SUCCESS) {
            fprintf(stderr, "'%s' is not a valid type: %s\n",
                word, isc_result_totext(result));
            goto failure;
        }
    } else {
        rdataclass = dns_rdataclass_in;
        result = dns_rdatatype_fromtext(&rdatatype, &region);
        if (result != ISC_R_SUCCESS) {
            fprintf(stderr, "'%s' is not a valid class or type: "
                "%s\n", word, isc_result_totext(result));
            goto failure;
        }
    }

    retval = parse_rdata(&cmdline, rdataclass, rdatatype, updatemsg,
                 rdata);
    if (retval != STATUS_MORE)
        goto failure;

    if (isdelete) {
        if ((rdata->flags & DNS_RDATA_UPDATE) != 0)
            rdataclass = dns_rdataclass_any;
        else
            rdataclass = dns_rdataclass_none;
    } else {
        if ((rdata->flags & DNS_RDATA_UPDATE) != 0) {
            fprintf(stderr, "could not read rdata\n");
            goto failure;
        }
    }

 doneparsing:

    result = dns_message_gettemprdatalist(updatemsg, &rdatalist);
    check_result(result, "dns_message_gettemprdatalist");
    result = dns_message_gettemprdataset(updatemsg, &rdataset);
    check_result(result, "dns_message_gettemprdataset");
    dns_rdatalist_init(rdatalist);
    rdatalist->type = rdatatype;
    rdatalist->rdclass = rdataclass;
    rdatalist->covers = rdatatype;
    rdatalist->ttl = (dns_ttl_t)ttl;
    ISC_LIST_INIT(rdatalist->rdata);
    ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
    dns_rdataset_init(rdataset);
    dns_rdatalist_tordataset(rdatalist, rdataset);
    ISC_LIST_INIT(name->list);
    ISC_LIST_APPEND(name->list, rdataset, link);
    dns_message_addname(updatemsg, name, DNS_SECTION_UPDATE);
    return (STATUS_MORE);

 failure:
    if (name != NULL)
        dns_message_puttempname(updatemsg, &name);
    if (rdata != NULL)
        dns_message_puttemprdata(updatemsg, &rdata);
    return (STATUS_SYNTAX);
}

static isc_uint16_t
evaluate_update(char *cmdline) {
    char *word;
    isc_boolean_t isdelete;

    ddebug("evaluate_update()");
    word = nsu_strsep(&cmdline, " \t\r\n");
    if (*word == 0) {
        fprintf(stderr, "could not read operation code\n");
        return (STATUS_SYNTAX);
    }
    if (strcasecmp(word, "delete") == 0)
        isdelete = ISC_TRUE;
    else if (strcasecmp(word, "add") == 0)
        isdelete = ISC_FALSE;
    else {
        fprintf(stderr, "incorrect operation code: %s\n", word);
        return (STATUS_SYNTAX);
    }
    return (update_addordelete(cmdline, isdelete));
}

static void
show_message(dns_message_t *msg) {
    isc_result_t result;
    isc_buffer_t *buf = NULL;
    int bufsz;

    ddebug("show_message()");
    bufsz = INITTEXT;
    do {
        if (bufsz > MAXTEXT) {
            fprintf(stderr, "could not allocate large enough "
                "buffer to display message\n");
            exit(1);
        }
        if (buf != NULL)
            isc_buffer_free(&buf);
        result = isc_buffer_allocate(mctx, &buf, bufsz);
        check_result(result, "isc_buffer_allocate");
        result = dns_message_totext(msg, style, 0, buf);
        bufsz *= 2;
    } while (result == ISC_R_NOSPACE);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "could not convert message to text format.\n");
        isc_buffer_free(&buf);
        return;
    }
    printf("Outgoing update query:\n%.*s",
           (int)isc_buffer_usedlength(buf),
           (char*)isc_buffer_base(buf));
    isc_buffer_free(&buf);
}


static isc_uint16_t
get_next_command(void) {
    char cmdlinebuf[MAXCMD];
    char *cmdline;
    char *word;

    ddebug("get_next_command()");
    if (interactive)
        fprintf(stdout, "> ");
    isc_app_block();
    cmdline = fgets(cmdlinebuf, MAXCMD, input);
    isc_app_unblock();
    if (cmdline == NULL)
        return (STATUS_QUIT);
    word = nsu_strsep(&cmdline, " \t\r\n");

    if (feof(input))
        return (STATUS_QUIT);
    if (*word == 0)
        return (STATUS_SEND);
    if (word[0] == ';')
        return (STATUS_MORE);
    if (strcasecmp(word, "quit") == 0)
        return (STATUS_QUIT);
    if (strcasecmp(word, "prereq") == 0)
        return (evaluate_prereq(cmdline));
    if (strcasecmp(word, "update") == 0)
        return (evaluate_update(cmdline));
    if (strcasecmp(word, "server") == 0)
        return (evaluate_server(cmdline));
    if (strcasecmp(word, "local") == 0)
        return (evaluate_local(cmdline));
    if (strcasecmp(word, "zone") == 0)
        return (evaluate_zone(cmdline));
    if (strcasecmp(word, "send") == 0)
        return (STATUS_SEND);
    if (strcasecmp(word, "show") == 0) {
        show_message(updatemsg);
        return (STATUS_MORE);
    }
    if (strcasecmp(word, "key") == 0)
        return (evaluate_key(cmdline));
    fprintf(stderr, "incorrect section name: %s\n", word);
    return (STATUS_SYNTAX);
}

static isc_boolean_t
user_interaction(void) {
    isc_uint16_t result = STATUS_MORE;

    ddebug("user_interaction()");
    while ((result == STATUS_MORE) || (result == STATUS_SYNTAX))
        result = get_next_command();
    if (result == STATUS_SEND)
        return (ISC_TRUE);
    return (ISC_FALSE);

}

static void
done_update(void) {
    isc_event_t *event = global_event;
    ddebug("done_update()");
    isc_task_send(global_task, &event);
}

static void
update_completed(isc_task_t *task, isc_event_t *event) {
    dns_requestevent_t *reqev = NULL;
    isc_result_t result;
    dns_message_t *rcvmsg = NULL;
    dns_request_t *request;

    UNUSED(task);

    ddebug("update_completed()");

    requests--;

    REQUIRE(event->ev_type == DNS_EVENT_REQUESTDONE);
    reqev = (dns_requestevent_t *)event;
    request = reqev->request;

    if (shuttingdown) {
        dns_request_destroy(&request);
        isc_event_free(&event);
        maybeshutdown();
        return;
    }

    if (reqev->result != ISC_R_SUCCESS) {
        fprintf(stderr, "; Communication with server failed: %s\n",
            isc_result_totext(reqev->result));
        seenerror = ISC_TRUE;
        goto done;
    }

    result = dns_message_create(mctx, DNS_MESSAGE_INTENTPARSE, &rcvmsg);
    check_result(result, "dns_message_create");
    result = dns_request_getresponse(request, rcvmsg,
                     DNS_MESSAGEPARSE_PRESERVEORDER);
    switch (result) {
    case ISC_R_SUCCESS:
        break;
    case DNS_R_CLOCKSKEW:
    case DNS_R_EXPECTEDTSIG:
    case DNS_R_TSIGERRORSET:
    case DNS_R_TSIGVERIFYFAILURE:
    case DNS_R_UNEXPECTEDTSIG:
        fprintf(stderr, "; TSIG error with server: %s\n",
            isc_result_totext(result));
        seenerror = ISC_TRUE;
        break;
    default:
        check_result(result, "dns_request_getresponse");
    }

    if (rcvmsg->rcode != dns_rcode_noerror)
        seenerror = ISC_TRUE;
    if (debugging) {
        isc_buffer_t *buf = NULL;
        int bufsz;

        bufsz = INITTEXT;
        do {
            if (bufsz > MAXTEXT) {
                fprintf(stderr, "could not allocate large "
                    "enough buffer to display message\n");
                exit(1);
            }
            if (buf != NULL)
                isc_buffer_free(&buf);
            result = isc_buffer_allocate(mctx, &buf, bufsz);
            check_result(result, "isc_buffer_allocate");
            result = dns_message_totext(rcvmsg, style, 0, buf);
            bufsz *= 2;
        } while (result == ISC_R_NOSPACE);
        check_result(result, "dns_message_totext");
        fprintf(stderr, "\nReply from update query:\n%.*s\n",
            (int)isc_buffer_usedlength(buf),
            (char*)isc_buffer_base(buf));
        isc_buffer_free(&buf);
    }
    dns_message_destroy(&rcvmsg);
 done:
    dns_request_destroy(&request);
    isc_event_free(&event);
    done_update();
}

static void
send_update(dns_name_t *zonename, isc_sockaddr_t *master,
        isc_sockaddr_t *srcaddr)
{
    isc_result_t result;
    dns_request_t *request = NULL;
    dns_name_t *name = NULL;
    dns_rdataset_t *rdataset = NULL;
    unsigned int options = 0;

    ddebug("send_update()");

    result = dns_message_gettempname(updatemsg, &name);
    check_result(result, "dns_message_gettempname");
    dns_name_init(name, NULL);
    dns_name_clone(zonename, name);
    result = dns_message_gettemprdataset(updatemsg, &rdataset);
    check_result(result, "dns_message_gettemprdataset");
    dns_rdataset_makequestion(rdataset, dns_rdataclass_in,
                  dns_rdatatype_soa);
    ISC_LIST_INIT(name->list);
    ISC_LIST_APPEND(name->list, rdataset, link);
    dns_message_addname(updatemsg, name, DNS_SECTION_ZONE);

    if (usevc)
        options |= DNS_REQUESTOPT_TCP;
    if (tsigkey == NULL && sig0key != NULL) {
        result = dns_message_setsig0key(updatemsg, sig0key);
        check_result(result, "dns_message_setsig0key");
    }
    if (debugging) {
        char addrbuf[ISC_SOCKADDR_FORMATSIZE];

        isc_sockaddr_format(master, addrbuf, sizeof(addrbuf));
        fprintf(stderr, "Sending update to %s\n", addrbuf);
    }
    result = dns_request_createvia3(requestmgr, updatemsg, srcaddr,
                    master, options, tsigkey, timeout,
                    udp_timeout, udp_retries, global_task,
                    update_completed, NULL, &request);
    check_result(result, "dns_request_createvia3");

    if (debugging)
        show_message(updatemsg);

    requests++;
}

static void
recvsoa(isc_task_t *task, isc_event_t *event) {
    dns_requestevent_t *reqev = NULL;
    dns_request_t *request = NULL;
    isc_result_t result, eresult;
    dns_message_t *rcvmsg = NULL;
    dns_section_t section;
    dns_name_t *name = NULL;
    dns_rdataset_t *soaset = NULL;
    dns_rdata_soa_t soa;
    dns_rdata_t soarr = DNS_RDATA_INIT;
    int pass = 0;
    dns_name_t master;
    isc_sockaddr_t *serveraddr, tempaddr;
    dns_name_t *zonename;
    nsu_requestinfo_t *reqinfo;
    dns_message_t *soaquery = NULL;
    isc_sockaddr_t *addr;
    isc_boolean_t seencname = ISC_FALSE;

    UNUSED(task);

    ddebug("recvsoa()");

    requests--;

    REQUIRE(event->ev_type == DNS_EVENT_REQUESTDONE);
    reqev = (dns_requestevent_t *)event;
    request = reqev->request;
    eresult = reqev->result;
    reqinfo = reqev->ev_arg;
    soaquery = reqinfo->msg;
    addr = reqinfo->addr;

    if (shuttingdown) {
        dns_request_destroy(&request);
        dns_message_destroy(&soaquery);
        isc_mem_put(mctx, reqinfo, sizeof(nsu_requestinfo_t));
        isc_event_free(&event);
        maybeshutdown();
        return;
    }

    if (eresult != ISC_R_SUCCESS) {
        char addrbuf[ISC_SOCKADDR_FORMATSIZE];

        isc_sockaddr_format(addr, addrbuf, sizeof(addrbuf));
        fprintf(stderr, "; Communication with %s failed: %s\n",
               addrbuf, isc_result_totext(eresult));
        if (userserver != NULL)
            fatal("could not talk to specified name server");
        else if (++ns_inuse >= lwconf->nsnext)
            fatal("could not talk to any default name server");
        ddebug("Destroying request [%p]", request);
        dns_request_destroy(&request);
        dns_message_renderreset(soaquery);
        sendrequest(localaddr, &servers[ns_inuse], soaquery, &request);
        isc_mem_put(mctx, reqinfo, sizeof(nsu_requestinfo_t));
        isc_event_free(&event);
        return;
    }
    isc_mem_put(mctx, reqinfo, sizeof(nsu_requestinfo_t));

    isc_event_free(&event);
    reqev = NULL;

    ddebug("About to create rcvmsg");
    result = dns_message_create(mctx, DNS_MESSAGE_INTENTPARSE, &rcvmsg);
    check_result(result, "dns_message_create");
    result = dns_request_getresponse(request, rcvmsg,
                     DNS_MESSAGEPARSE_PRESERVEORDER);
    check_result(result, "dns_request_getresponse");
    section = DNS_SECTION_ANSWER;
    if (debugging) {
        isc_buffer_t *buf = NULL;
        int bufsz;
        bufsz = INITTEXT;
        do {
            if (buf != NULL)
                isc_buffer_free(&buf);
            if (bufsz > MAXTEXT) {
                fprintf(stderr, "could not allocate enough "
                     "space for debugging message\n");
                exit(1);
            }
            result = isc_buffer_allocate(mctx, &buf, bufsz);
            check_result(result, "isc_buffer_allocate");
            result = dns_message_totext(rcvmsg, style, 0, buf);
        } while (result == ISC_R_NOSPACE);
        check_result(result, "dns_message_totext");
        fprintf(stderr, "Reply from SOA query:\n%.*s\n",
            (int)isc_buffer_usedlength(buf),
            (char*)isc_buffer_base(buf));
        isc_buffer_free(&buf);
    }

    if (rcvmsg->rcode != dns_rcode_noerror &&
        rcvmsg->rcode != dns_rcode_nxdomain)
        fatal("response to SOA query was unsuccessful");

 lookforsoa:
    if (pass == 0)
        section = DNS_SECTION_ANSWER;
    else if (pass == 1)
        section = DNS_SECTION_AUTHORITY;
    else
        fatal("response to SOA query didn't contain an SOA");


    result = dns_message_firstname(rcvmsg, section);
    if (result != ISC_R_SUCCESS) {
        pass++;
        goto lookforsoa;
    }
    while (result == ISC_R_SUCCESS) {
        name = NULL;
        dns_message_currentname(rcvmsg, section, &name);
        soaset = NULL;
        result = dns_message_findtype(name, dns_rdatatype_soa, 0,
                          &soaset);
        if (result == ISC_R_SUCCESS)
            break;
        if (section == DNS_SECTION_ANSWER) {
            dns_rdataset_t *tset = NULL;
            if (dns_message_findtype(name, dns_rdatatype_cname, 0,
                         &tset) == ISC_R_SUCCESS
                ||
                dns_message_findtype(name, dns_rdatatype_dname, 0,
                         &tset) == ISC_R_SUCCESS
                )
            {
                seencname = ISC_TRUE;
                break;
            }
        }

        result = dns_message_nextname(rcvmsg, section);
    }

    if (soaset == NULL && !seencname) {
        pass++;
        goto lookforsoa;
    }

    if (seencname) {
        dns_name_t tname;
        unsigned int nlabels;

        result = dns_message_firstname(soaquery, DNS_SECTION_QUESTION);
        INSIST(result == ISC_R_SUCCESS);
        name = NULL;
        dns_message_currentname(soaquery, DNS_SECTION_QUESTION, &name);
        nlabels = dns_name_countlabels(name);
        if (nlabels == 1)
            fatal("could not find enclosing zone");
        dns_name_init(&tname, NULL);
        dns_name_getlabelsequence(name, 1, nlabels - 1, &tname);
        dns_name_clone(&tname, name);
        dns_request_destroy(&request);
        dns_message_renderreset(soaquery);
        if (userserver != NULL)
            sendrequest(localaddr, userserver, soaquery, &request);
        else
            sendrequest(localaddr, &servers[ns_inuse], soaquery,
                    &request);
        goto out;
    }

    if (debugging) {
        char namestr[DNS_NAME_FORMATSIZE];
        dns_name_format(name, namestr, sizeof(namestr));
        fprintf(stderr, "Found zone name: %s\n", namestr);
    }

    result = dns_rdataset_first(soaset);
    check_result(result, "dns_rdataset_first");

    dns_rdata_init(&soarr);
    dns_rdataset_current(soaset, &soarr);
    result = dns_rdata_tostruct(&soarr, &soa, NULL);
    check_result(result, "dns_rdata_tostruct");

    dns_name_init(&master, NULL);
    dns_name_clone(&soa.origin, &master);

    if (userzone != NULL)
        zonename = userzone;
    else
        zonename = name;

    if (debugging) {
        char namestr[DNS_NAME_FORMATSIZE];
        dns_name_format(&master, namestr, sizeof(namestr));
        fprintf(stderr, "The master is: %s\n", namestr);
    }

    if (userserver != NULL)
        serveraddr = userserver;
    else {
        char serverstr[DNS_NAME_MAXTEXT+1];
        isc_buffer_t buf;

        isc_buffer_init(&buf, serverstr, sizeof(serverstr));
        result = dns_name_totext(&master, ISC_TRUE, &buf);
        check_result(result, "dns_name_totext");
        serverstr[isc_buffer_usedlength(&buf)] = 0;
        get_address(serverstr, DNSDEFAULTPORT, &tempaddr);
        serveraddr = &tempaddr;
    }

    send_update(zonename, serveraddr, localaddr);

    dns_message_destroy(&soaquery);
    dns_request_destroy(&request);

 out:
    dns_rdata_freestruct(&soa);
    dns_message_destroy(&rcvmsg);
    ddebug("Out of recvsoa");
}

static void
sendrequest(isc_sockaddr_t *srcaddr, isc_sockaddr_t *destaddr,
        dns_message_t *msg, dns_request_t **request)
{
    isc_result_t result;
    nsu_requestinfo_t *reqinfo;

    reqinfo = isc_mem_get(mctx, sizeof(nsu_requestinfo_t));
    if (reqinfo == NULL)
        fatal("out of memory");
    reqinfo->msg = msg;
    reqinfo->addr = destaddr;
    result = dns_request_createvia3(requestmgr, msg, srcaddr, destaddr,
                    0, NULL, FIND_TIMEOUT * 20,
                    FIND_TIMEOUT, 3, global_task, recvsoa,
                    reqinfo, request);
    check_result(result, "dns_request_createvia");
    requests++;
}

static void
start_update(void) {
    isc_result_t result;
    dns_rdataset_t *rdataset = NULL;
    dns_name_t *name = NULL;
    dns_request_t *request = NULL;
    dns_message_t *soaquery = NULL;
    dns_name_t *firstname;

    ddebug("start_update()");

    result = dns_message_firstname(updatemsg, DNS_SECTION_UPDATE);
    if (result != ISC_R_SUCCESS) {
        done_update();
        return;
    }

    if (userzone != NULL && userserver != NULL) {
        send_update(userzone, userserver, localaddr);
        return;
    }

    result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
                    &soaquery);
    check_result(result, "dns_message_create");

    soaquery->flags |= DNS_MESSAGEFLAG_RD;

    result = dns_message_gettempname(soaquery, &name);
    check_result(result, "dns_message_gettempname");

    result = dns_message_gettemprdataset(soaquery, &rdataset);
    check_result(result, "dns_message_gettemprdataset");

    dns_rdataset_makequestion(rdataset, dns_rdataclass_in,
                  dns_rdatatype_soa);

    firstname = NULL;
    dns_message_currentname(updatemsg, DNS_SECTION_UPDATE, &firstname);
    dns_name_init(name, NULL);
    dns_name_clone(firstname, name);

    ISC_LIST_INIT(name->list);
    ISC_LIST_APPEND(name->list, rdataset, link);
    dns_message_addname(soaquery, name, DNS_SECTION_QUESTION);

    if (userserver != NULL)
        sendrequest(localaddr, userserver, soaquery, &request);
    else {
        ns_inuse = 0;
        sendrequest(localaddr, &servers[ns_inuse], soaquery, &request);
    }
}

static void
cleanup(void) {
    ddebug("cleanup()");

    ddebug("Shutting down task manager");
    isc_taskmgr_destroy(&taskmgr);

    ddebug("Destroying event");
    isc_event_free(&global_event);

    ddebug("Shutting down socket manager");
    isc_socketmgr_destroy(&socketmgr);

    ddebug("Shutting down timer manager");
    isc_timermgr_destroy(&timermgr);

    ddebug("Destroying memory context");
    if (memdebugging)
        isc_mem_stats(mctx, stderr);
    isc_mem_destroy(&mctx);
}

static void
getinput(isc_task_t *task, isc_event_t *event) {
    isc_boolean_t more;

    UNUSED(task);

    if (shuttingdown) {
        maybeshutdown();
        return;
    }

    if (global_event == NULL)
        global_event = event;

    reset_system();
    more = user_interaction();
    if (!more) {
        isc_app_shutdown();
        return;
    }
    start_update();
    return;
}

int
main(int argc, char **argv) {
    isc_result_t result;
    style = &dns_master_style_debug;

    input = stdin;

    isc_app_start();

    parse_args(argc, argv);

    setup_system();

    result = isc_app_onrun(mctx, global_task, getinput, NULL);
    check_result(result, "isc_app_onrun");

    (void)isc_app_run();

    cleanup();

    isc_app_finish();

    if (seenerror)
        return (2);
    else
        return (0);
}