bin/dig/dighost.c

	dighost.c revision c73c1c33ec9569c8f9ffd205b48f044f9b03795b
/*
 * Copyright (C) 2000, 2001  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: dighost.c,v 1.239 2002/02/12 02:10:30 marka Exp $ */

/*
 * Notice to programmers:  Do not use this code as an example of how to
 * use the ISC library to perform DNS lookups.  Dig and Host both operate
 * on the request level, since they allow fine-tuning of output and are
 * intended as debugging tools.  As a result, they perform many of the
 * functions which could be better handled using the dns_resolver
 * functions in most applications.
 */

#include <config.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>

#include <dns/byaddr.h>
#include <dns/fixedname.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/result.h>
#include <dns/tsig.h>

#include <dst/dst.h>

#include <isc/app.h>
#include <isc/base64.h>
#include <isc/entropy.h>
#include <isc/lang.h>
#include <isc/netaddr.h>
#include <isc/print.h>
#include <isc/result.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/types.h>
#include <isc/util.h>

#include <bind9/getaddresses.h>

#include <dig/dig.h>

ISC_LIST(dig_lookup_t) lookup_list;
dig_serverlist_t server_list;
ISC_LIST(dig_searchlist_t) search_list;

isc_boolean_t
    have_ipv4 = ISC_FALSE,
    have_ipv6 = ISC_FALSE,
    specified_source = ISC_FALSE,
    free_now = ISC_FALSE,
    cancel_now = ISC_FALSE,
    usesearch = ISC_FALSE,
    qr = ISC_FALSE,
    is_dst_up = ISC_FALSE;
in_port_t port = 53;
unsigned int timeout = 0;
isc_mem_t *mctx = NULL;
isc_taskmgr_t *taskmgr = NULL;
isc_task_t *global_task = NULL;
isc_timermgr_t *timermgr = NULL;
isc_socketmgr_t *socketmgr = NULL;
isc_sockaddr_t bind_address;
isc_sockaddr_t bind_any;
int sendcount = 0;
int recvcount = 0;
int sockcount = 0;
int ndots = -1;
int tries = 3;
int lookup_counter = 0;

/*
 * Exit Codes:
 *   0   Everything went well, including things like NXDOMAIN
 *   1   Usage error
 *   7   Got too many RR's or Names
 *   8   Couldn't open batch file
 *   9   No reply from server
 *   10  Internal error
 */
int exitcode = 0;
char keynametext[MXNAME];
char keyfile[MXNAME] = "";
char keysecret[MXNAME] = "";
isc_buffer_t *namebuf = NULL;
dns_tsigkey_t *key = NULL;
isc_boolean_t validated = ISC_TRUE;
isc_entropy_t *entp = NULL;
isc_mempool_t *commctx = NULL;
isc_boolean_t debugging = ISC_FALSE;
isc_boolean_t memdebugging = ISC_FALSE;
char *progname = NULL;
isc_mutex_t lookup_lock;
dig_lookup_t *current_lookup = NULL;

/*
 * Apply and clear locks at the event level in global task.
 * Can I get rid of these using shutdown events?  XXX
 */
#define LOCK_LOOKUP {\
    debug("lock_lookup %s:%d", __FILE__, __LINE__);\
    check_result(isc_mutex_lock((&lookup_lock)), "isc_mutex_lock");\
    debug("success");\
}
#define UNLOCK_LOOKUP {\
    debug("unlock_lookup %s:%d", __FILE__, __LINE__);\
    check_result(isc_mutex_unlock((&lookup_lock)),\
             "isc_mutex_unlock");\
}

static void
cancel_lookup(dig_lookup_t *lookup);

static void
recv_done(isc_task_t *task, isc_event_t *event);

static void
connect_timeout(isc_task_t *task, isc_event_t *event);

static void
launch_next_query(dig_query_t *query, isc_boolean_t include_question);

char *
next_token(char **stringp, const char *delim) {
    char *res;

    do {
        res = strsep(stringp, delim);
        if (res == NULL)
            break;
    } while (*res == '\0');
    return (res);
}

static int
count_dots(char *string) {
    char *s;
    int i = 0;

    s = string;
    while (*s != '\0') {
        if (*s == '.')
            i++;
        s++;
    }
    return (i);
}

static void
hex_dump(isc_buffer_t *b) {
    unsigned int len;
    isc_region_t r;

    isc_buffer_usedregion(b, &r);

    printf("%d bytes\n", r.length);
    for (len = 0; len < r.length; len++) {
        printf("%02x ", r.base[len]);
        if (len % 16 == 15)
            printf("\n");
    }
    if (len % 16 != 0)
        printf("\n");
}

/*
 * Append 'len' bytes of 'text' at '*p', failing with
 * ISC_R_NOSPACE if that would advance p past 'end'.
 */
static isc_result_t
append(const char *text, int len, char **p, char *end) {
    if (len > end - *p)
        return (ISC_R_NOSPACE);
    memcpy(*p, text, len);
    *p += len;
    return (ISC_R_SUCCESS);
}

static isc_result_t
reverse_octets(const char *in, char **p, char *end) {
    char *dot = strchr(in, '.');
    int len;
    if (dot != NULL) {
        isc_result_t result;
        result = reverse_octets(dot + 1, p, end);
        if (result != ISC_R_SUCCESS)
            return (result);
        result = append(".", 1, p, end);
        if (result != ISC_R_SUCCESS)
            return (result);
        len = dot - in;
    } else {
        len = strlen(in);
    }
    return (append(in, len, p, end));
}

isc_result_t
get_reverse(char *reverse, char *value, isc_boolean_t nibble,
        isc_boolean_t strict)
{
    int r;
    isc_result_t result;
    isc_netaddr_t addr;

    addr.family = AF_INET6;
    r = inet_pton(AF_INET6, value, &addr.type.in6);
    if (r > 0) {
        /* This is a valid IPv6 address. */
        dns_fixedname_t fname;
        dns_name_t *name;
        dns_fixedname_init(&fname);
        name = dns_fixedname_name(&fname);
        result = dns_byaddr_createptrname(&addr, nibble, name);
        if (result != ISC_R_SUCCESS)
            return (result);
        dns_name_format(name, reverse, MXNAME);
        return (ISC_R_SUCCESS);
    } else {
        /*
         * Not a valid IPv6 address.  Assume IPv4.
         * If 'strict' is not set, construct the
         * in-addr.arpa name by blindly reversing
         * octets whether or not they look like integers,
         * so that this can be used for RFC2317 names
         * and such.
         */
        char *p = reverse;
        char *end = reverse + MXNAME;
        if (strict) {
            int adrs[4];
            int n;
            if (strspn(value, "0123456789.") != strlen(value))
                return (DNS_R_BADDOTTEDQUAD);
            n = sscanf(value, "%d.%d.%d.%d",
                   &adrs[0], &adrs[1],
                   &adrs[2], &adrs[3]);
            if (n == 0)
                return (DNS_R_BADDOTTEDQUAD);
        }
        result = reverse_octets(value, &p, end);
        if (result != ISC_R_SUCCESS)
            return (result);
        /* Append .in-addr.arpa. and a terminating NUL. */
        result = append(".in-addr.arpa.", 15, &p, end);
        if (result != ISC_R_SUCCESS)
            return (result);
        return (ISC_R_SUCCESS);
    }
}

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

    fprintf(stderr, "%s: ", progname);
    va_start(args, format);
    vfprintf(stderr, format, args);
    va_end(args);
    fprintf(stderr, "\n");
    if (exitcode < 10)
        exitcode = 10;
    exit(exitcode);
}

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

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

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

/*
 * Create a server structure, which is part of the lookup structure.
 * This is little more than a linked list of servers to query in hopes
 * of finding the answer the user is looking for
 */
dig_server_t *
make_server(const char *servname) {
    dig_server_t *srv;

    REQUIRE(servname != NULL);

    debug("make_server(%s)", servname);
    srv = isc_mem_allocate(mctx, sizeof(struct dig_server));
    if (srv == NULL)
        fatal("memory allocation failure in %s:%d",
              __FILE__, __LINE__);
    strncpy(srv->servername, servname, MXNAME);
    srv->servername[MXNAME-1] = 0;
    ISC_LINK_INIT(srv, link);
    return (srv);
}

/*
 * Produce a cloned server list.  The dest list must have already had
 * ISC_LIST_INIT applied.
 */
void
clone_server_list(dig_serverlist_t src, dig_serverlist_t *dest) {
    dig_server_t *srv, *newsrv;

    debug("clone_server_list()");
    srv = ISC_LIST_HEAD(src);
    while (srv != NULL) {
        newsrv = make_server(srv->servername);
        ISC_LINK_INIT(newsrv, link);
        ISC_LIST_ENQUEUE(*dest, newsrv, link);
        srv = ISC_LIST_NEXT(srv, link);
    }
}

/*
 * Create an empty lookup structure, which holds all the information needed
 * to get an answer to a user's question.  This structure contains two
 * linked lists: the server list (servers to query) and the query list
 * (outstanding queries which have been made to the listed servers).
 */
dig_lookup_t *
make_empty_lookup(void) {
    dig_lookup_t *looknew;

    debug("make_empty_lookup()");

    INSIST(!free_now);

    looknew = isc_mem_allocate(mctx, sizeof(struct dig_lookup));
    if (looknew == NULL)
        fatal("memory allocation failure in %s:%d",
               __FILE__, __LINE__);
    looknew->pending = ISC_TRUE;
    looknew->textname[0] = 0;
    looknew->cmdline[0] = 0;
    looknew->rdtype = dns_rdatatype_a;
    looknew->qrdtype = dns_rdatatype_a;
    looknew->rdclass = dns_rdataclass_in;
    looknew->rdtypeset = ISC_FALSE;
    looknew->rdclassset = ISC_FALSE;
    looknew->sendspace = NULL;
    looknew->sendmsg = NULL;
    looknew->name = NULL;
    looknew->oname = NULL;
    looknew->timer = NULL;
    looknew->xfr_q = NULL;
    looknew->current_query = NULL;
    looknew->doing_xfr = ISC_FALSE;
    looknew->ixfr_serial = ISC_FALSE;
    looknew->trace = ISC_FALSE;
    looknew->trace_root = ISC_FALSE;
    looknew->identify = ISC_FALSE;
    looknew->identify_previous_line = ISC_FALSE;
    looknew->ignore = ISC_FALSE;
    looknew->servfail_stops = ISC_TRUE;
    looknew->besteffort = ISC_TRUE;
    looknew->dnssec = ISC_FALSE;
    looknew->udpsize = 0;
    looknew->recurse = ISC_TRUE;
    looknew->aaonly = ISC_FALSE;
    looknew->adflag = ISC_FALSE;
    looknew->cdflag = ISC_FALSE;
    looknew->ns_search_only = ISC_FALSE;
    looknew->origin = NULL;
    looknew->tsigctx = NULL;
    looknew->querysig = NULL;
    looknew->retries = tries;
    looknew->nsfound = 0;
    looknew->tcp_mode = ISC_FALSE;
    looknew->nibble = ISC_FALSE;
    looknew->comments = ISC_TRUE;
    looknew->stats = ISC_TRUE;
    looknew->section_question = ISC_TRUE;
    looknew->section_answer = ISC_TRUE;
    looknew->section_authority = ISC_TRUE;
    looknew->section_additional = ISC_TRUE;
    looknew->new_search = ISC_FALSE;
    ISC_LINK_INIT(looknew, link);
    ISC_LIST_INIT(looknew->q);
    ISC_LIST_INIT(looknew->my_server_list);
    return (looknew);
}

/*
 * Clone a lookup, perhaps copying the server list.  This does not clone
 * the query list, since it will be regenerated by the setup_lookup()
 * function, nor does it queue up the new lookup for processing.
 * Caution: If you don't clone the servers, you MUST clone the server
 * list seperately from somewhere else, or construct it by hand.
 */
dig_lookup_t *
clone_lookup(dig_lookup_t *lookold, isc_boolean_t servers) {
    dig_lookup_t *looknew;

    debug("clone_lookup()");

    INSIST(!free_now);

    looknew = make_empty_lookup();
    INSIST(looknew != NULL);
    strncpy(looknew->textname, lookold->textname, MXNAME);
    strncpy(looknew->cmdline, lookold->cmdline, MXNAME);
    looknew->textname[MXNAME-1] = 0;
    looknew->rdtype = lookold->rdtype;
    looknew->qrdtype = lookold->qrdtype;
    looknew->rdclass = lookold->rdclass;
    looknew->rdtypeset = lookold->rdtypeset;
    looknew->rdclassset = lookold->rdclassset;
    looknew->doing_xfr = lookold->doing_xfr;
    looknew->ixfr_serial = lookold->ixfr_serial;
    looknew->trace = lookold->trace;
    looknew->trace_root = lookold->trace_root;
    looknew->identify = lookold->identify;
    looknew->identify_previous_line = lookold->identify_previous_line;
    looknew->ignore = lookold->ignore;
    looknew->servfail_stops = lookold->servfail_stops;
    looknew->besteffort = lookold->besteffort;
    looknew->dnssec = lookold->dnssec;
    looknew->udpsize = lookold->udpsize;
    looknew->recurse = lookold->recurse;
    looknew->aaonly = lookold->aaonly;
    looknew->adflag = lookold->adflag;
    looknew->cdflag = lookold->cdflag;
    looknew->ns_search_only = lookold->ns_search_only;
    looknew->tcp_mode = lookold->tcp_mode;
    looknew->comments = lookold->comments;
    looknew->stats = lookold->stats;
    looknew->section_question = lookold->section_question;
    looknew->section_answer = lookold->section_answer;
    looknew->section_authority = lookold->section_authority;
    looknew->section_additional = lookold->section_additional;
    looknew->retries = lookold->retries;
    looknew->tsigctx = NULL;

    if (servers)
        clone_server_list(lookold->my_server_list,
                  &looknew->my_server_list);
    return (looknew);
}

/*
 * Requeue a lookup for further processing, perhaps copying the server
 * list.  The new lookup structure is returned to the caller, and is
 * queued for processing.  If servers are not cloned in the requeue, they
 * must be added before allowing the current event to complete, since the
 * completion of the event may result in the next entry on the lookup
 * queue getting run.
 */
dig_lookup_t *
requeue_lookup(dig_lookup_t *lookold, isc_boolean_t servers) {
    dig_lookup_t *looknew;

    debug("requeue_lookup()");

    lookup_counter++;
    if (lookup_counter > LOOKUP_LIMIT)
        fatal("too many lookups");

    looknew = clone_lookup(lookold, servers);
    INSIST(looknew != NULL);

    debug("before insertion, init@%p -> %p, new@%p -> %p",
          lookold, lookold->link.next, looknew, looknew->link.next);
    ISC_LIST_PREPEND(lookup_list, looknew, link);
    debug("after insertion, init -> %p, new = %p, new -> %p",
          lookold, looknew, looknew->link.next);
    return (looknew);
}


static void
setup_text_key(void) {
    isc_result_t result;
    dns_name_t keyname;
    isc_buffer_t secretbuf;
    int secretsize;
    unsigned char *secretstore;

    debug("setup_text_key()");
    result = isc_buffer_allocate(mctx, &namebuf, MXNAME);
    check_result(result, "isc_buffer_allocate");
    dns_name_init(&keyname, NULL);
    check_result(result, "dns_name_init");
    isc_buffer_putstr(namebuf, keynametext);
    secretsize = strlen(keysecret) * 3 / 4;
    secretstore = isc_mem_allocate(mctx, secretsize);
    if (secretstore == NULL)
        fatal("memory allocation failure in %s:%d",
              __FILE__, __LINE__);
    isc_buffer_init(&secretbuf, secretstore, secretsize);
    result = isc_base64_decodestring(keysecret, &secretbuf);
    if (result != ISC_R_SUCCESS)
        goto failure;

    secretsize = isc_buffer_usedlength(&secretbuf);

    result = dns_name_fromtext(&keyname, namebuf,
                   dns_rootname, ISC_FALSE,
                   namebuf);
    if (result != ISC_R_SUCCESS)
        goto failure;

    result = dns_tsigkey_create(&keyname, dns_tsig_hmacmd5_name,
                    secretstore, secretsize,
                    ISC_FALSE, NULL, 0, 0, mctx,
                    NULL, &key);
 failure:
    if (result != ISC_R_SUCCESS)
        printf(";; Couldn't create key %s: %s\n",
               keynametext, isc_result_totext(result));

    isc_mem_free(mctx, secretstore);
    dns_name_invalidate(&keyname);
    isc_buffer_free(&namebuf);
}

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

    debug("setup_file_key()");
    result = dst_key_fromnamedfile(keyfile, DST_TYPE_PRIVATE,
                       mctx, &dstkey);
    if (result != ISC_R_SUCCESS) {
        fprintf(stderr, "Couldn't read key from %s: %s\n",
            keyfile, isc_result_totext(result));
        goto failure;
    }

    result = dns_tsigkey_createfromkey(dst_key_name(dstkey),
                       dns_tsig_hmacmd5_name,
                       dstkey, ISC_FALSE, NULL, 0, 0,
                       mctx, NULL, &key);
    if (result != ISC_R_SUCCESS) {
        printf(";; Couldn't create key %s: %s\n",
               keynametext, isc_result_totext(result));
        goto failure;
    }
    dstkey = NULL;
 failure:
    if (dstkey != NULL)
        dst_key_free(&dstkey);
}

static dig_searchlist_t *
make_searchlist_entry(char *domain) {
    dig_searchlist_t *search;
    search = isc_mem_allocate(mctx, sizeof(*search));
    if (search == NULL)
        fatal("memory allocation failure in %s:%d",
              __FILE__, __LINE__);
    strncpy(search->origin, domain, MXNAME);
    search->origin[MXNAME-1] = 0;
    ISC_LINK_INIT(search, link);
    return (search);
}

/*
 * Setup the system as a whole, reading key information and resolv.conf
 * settings.
 */
void
setup_system(void) {
    char rcinput[MXNAME];
    FILE *fp;
    char *ptr;
    dig_server_t *srv;
    dig_searchlist_t *search, *domain = NULL;
    isc_boolean_t get_servers;
    char *input;

    debug("setup_system()");

    free_now = ISC_FALSE;
    get_servers = ISC_TF(server_list.head == NULL);
    fp = fopen(RESOLV_CONF, "r");
    /* XXX Use lwres resolv.conf reader */
    if (fp == NULL)
        goto no_file;

    while (fgets(rcinput, MXNAME, fp) != 0) {
        input = rcinput;
        ptr = next_token(&input, " \t\r\n");
        if (ptr != NULL) {
            if (get_servers &&
                strcasecmp(ptr, "nameserver") == 0) {
                debug("got a nameserver line");
                ptr = next_token(&input, " \t\r\n");
                if (ptr != NULL) {
                    srv = make_server(ptr);
                    ISC_LIST_APPEND(server_list, srv, link);
                }
            } else if (strcasecmp(ptr, "options") == 0) {
                ptr = next_token(&input, " \t\r\n");
                if (ptr != NULL) {
                    if (strncasecmp(ptr, "ndots:", 6) == 0
                        && ndots == -1)
                    {
                        ndots = atoi(&ptr[6]);
                        debug("ndots is %d.", ndots);
                    }
                }
            } else if (strcasecmp(ptr, "search") == 0){
                while ((ptr = next_token(&input, " \t\r\n"))
                       != NULL) {
                    debug("adding search %s", ptr);
                    search = make_searchlist_entry(ptr);
                    ISC_LIST_INITANDAPPEND(search_list,
                                   search, link);
                }
            } else if (strcasecmp(ptr, "domain") == 0) {
                while ((ptr = next_token(&input, " \t\r\n"))
                       != NULL) {
                    if (domain != NULL)
                        isc_mem_free(mctx, domain);
                    domain = make_searchlist_entry(ptr);
                }
            }
        }
    }
    fclose(fp);
 no_file:

    if (ISC_LIST_EMPTY(search_list) && domain != NULL) {
        ISC_LIST_INITANDAPPEND(search_list, domain, link);
        domain = NULL;
    }
    if (domain != NULL)
        isc_mem_free(mctx, domain);

    if (ndots == -1)
        ndots = 1;

    if (server_list.head == NULL) {
        srv = make_server("127.0.0.1");
        ISC_LIST_APPEND(server_list, srv, link);
    }

    if (keyfile[0] != 0)
        setup_file_key();
    else if (keysecret[0] != 0)
        setup_text_key();
}

static void
clear_searchlist(void) {
    dig_searchlist_t *search;
    while ((search = ISC_LIST_HEAD(search_list)) != NULL) {
        ISC_LIST_UNLINK(search_list, search, link);
        isc_mem_free(mctx, search);
    }
}

/*
 * Override the search list derived from resolv.conf by 'domain'.
 */
void
set_search_domain(char *domain) {
    dig_searchlist_t *search;

    clear_searchlist();
    search = make_searchlist_entry(domain);
    ISC_LIST_APPEND(search_list, search, link);
}

/*
 * Setup the ISC and DNS libraries for use by the system.
 */
void
setup_libs(void) {
    isc_result_t result;

    debug("setup_libs()");

    /*
     * Warning: This is not particularly good randomness.  We'll
     * just use random() now for getting id values, but doing so
     * does NOT ensure that id's can't be guessed.
     */
    srandom(getpid());

    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_ipv6 && !have_ipv4)
        fatal("can't find either v4 or v6 networking");

    result = isc_mem_create(0, 0, &mctx);
    check_result(result, "isc_mem_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_timermgr_create(mctx, &timermgr);
    check_result(result, "isc_timermgr_create");

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

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

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

    result = isc_mempool_create(mctx, COMMSIZE, &commctx);
    check_result(result, "isc_mempool_create");
    isc_mempool_setname(commctx, "COMMPOOL");
    /*
     * 6 and 2 set as reasonable parameters for 3 or 4 nameserver
     * systems.
     */
    isc_mempool_setfreemax(commctx, 6);
    isc_mempool_setfillcount(commctx, 2);

    result = isc_mutex_init(&lookup_lock);
    check_result(result, "isc_mutex_init");

    dns_result_register();
}

/*
 * Add EDNS0 option record to a message.  Currently, the only supported
 * options are UDP buffer size and the DO bit.
 */
static void
add_opt(dns_message_t *msg, isc_uint16_t udpsize, isc_boolean_t dnssec) {
    dns_rdataset_t *rdataset = NULL;
    dns_rdatalist_t *rdatalist = NULL;
    dns_rdata_t *rdata = NULL;
    isc_result_t result;

    debug("add_opt()");
    result = dns_message_gettemprdataset(msg, &rdataset);
    check_result(result, "dns_message_gettemprdataset");
    dns_rdataset_init(rdataset);
    result = dns_message_gettemprdatalist(msg, &rdatalist);
    check_result(result, "dns_message_gettemprdatalist");
    result = dns_message_gettemprdata(msg, &rdata);
    check_result(result, "dns_message_gettemprdata");

    debug("setting udp size of %d", udpsize);
    rdatalist->type = dns_rdatatype_opt;
    rdatalist->covers = 0;
    rdatalist->rdclass = udpsize;
    rdatalist->ttl = 0;
    if (dnssec)
        rdatalist->ttl = DNS_MESSAGEEXTFLAG_DO;
    rdata->data = NULL;
    rdata->length = 0;
    ISC_LIST_INIT(rdatalist->rdata);
    ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
    dns_rdatalist_tordataset(rdatalist, rdataset);
    result = dns_message_setopt(msg, rdataset);
    check_result(result, "dns_message_setopt");
}

/*
 * Add a question section to a message, asking for the specified name,
 * type, and class.
 */
static void
add_question(dns_message_t *message, dns_name_t *name,
         dns_rdataclass_t rdclass, dns_rdatatype_t rdtype)
{
    dns_rdataset_t *rdataset;
    isc_result_t result;

    debug("add_question()");
    rdataset = NULL;
    result = dns_message_gettemprdataset(message, &rdataset);
    check_result(result, "dns_message_gettemprdataset()");
    dns_rdataset_init(rdataset);
    dns_rdataset_makequestion(rdataset, rdclass, rdtype);
    ISC_LIST_APPEND(name->list, rdataset, link);
}

/*
 * Check if we're done with all the queued lookups, which is true iff
 * all sockets, sends, and recvs are accounted for (counters == 0),
 * and the lookup list is empty.
 * If we are done, pass control back out to dighost_shutdown() (which is
 * part of dig.c, host.c, or nslookup.c) to either shutdown the system as
 * a whole or reseed the lookup list.
 */
static void
check_if_done(void) {
    debug("check_if_done()");
    debug("list %s", ISC_LIST_EMPTY(lookup_list) ? "empty" : "full");
    if (ISC_LIST_EMPTY(lookup_list) && current_lookup == NULL &&
        sendcount == 0) {
        INSIST(sockcount == 0);
        INSIST(recvcount == 0);
        debug("shutting down");
        dighost_shutdown();
    }
}

/*
 * Clear out a query when we're done with it.  WARNING: This routine
 * WILL invalidate the query pointer.
 */
static void
clear_query(dig_query_t *query) {
    dig_lookup_t *lookup;

    REQUIRE(query != NULL);

    debug("clear_query(%p)", query);

    lookup = query->lookup;

    if (lookup->current_query == query)
        lookup->current_query = NULL;

    ISC_LIST_UNLINK(lookup->q, query, link);
    if (ISC_LINK_LINKED(&query->recvbuf, link))
        ISC_LIST_DEQUEUE(query->recvlist, &query->recvbuf,
                 link);
    if (ISC_LINK_LINKED(&query->lengthbuf, link))
        ISC_LIST_DEQUEUE(query->lengthlist, &query->lengthbuf,
                 link);
    INSIST(query->recvspace != NULL);
    if (query->sock != NULL) {
        isc_socket_detach(&query->sock);
        sockcount--;
        debug("sockcount=%d", sockcount);
    }
    isc_mempool_put(commctx, query->recvspace);
    isc_buffer_invalidate(&query->recvbuf);
    isc_buffer_invalidate(&query->lengthbuf);
    isc_mem_free(mctx, query);
}

/*
 * Try and clear out a lookup if we're done with it.  Return ISC_TRUE if
 * the lookup was successfully cleared.  If ISC_TRUE is returned, the
 * lookup pointer has been invalidated.
 */
static isc_boolean_t
try_clear_lookup(dig_lookup_t *lookup) {
    dig_server_t *s;
    dig_query_t *q;
    void *ptr;

    REQUIRE(lookup != NULL);

    debug("try_clear_lookup(%p)", lookup);

    if (ISC_LIST_HEAD(lookup->q) != NULL) {
        if (debugging) {
            q = ISC_LIST_HEAD(lookup->q);
            while (q != NULL) {
                debug("query to %s still pending",
                       q->servname);
                q = ISC_LIST_NEXT(q, link);
            }
            return (ISC_FALSE);
        }
    }
    /*
     * At this point, we know there are no queries on the lookup,
     * so can make it go away also.
     */
    debug("cleared");
    s = ISC_LIST_HEAD(lookup->my_server_list);
    while (s != NULL) {
        debug("freeing server %p belonging to %p",
              s, lookup);
        ptr = s;
        s = ISC_LIST_NEXT(s, link);
        ISC_LIST_DEQUEUE(lookup->my_server_list,
                 (dig_server_t *)ptr, link);
        isc_mem_free(mctx, ptr);
    }
    if (lookup->sendmsg != NULL)
        dns_message_destroy(&lookup->sendmsg);
    if (lookup->querysig != NULL) {
        debug("freeing buffer %p", lookup->querysig);
        isc_buffer_free(&lookup->querysig);
    }
    if (lookup->timer != NULL)
        isc_timer_detach(&lookup->timer);
    if (lookup->sendspace != NULL)
        isc_mempool_put(commctx, lookup->sendspace);

    if (lookup->tsigctx != NULL)
        dst_context_destroy(&lookup->tsigctx);

    isc_mem_free(mctx, lookup);
    return (ISC_TRUE);
}


/*
 * If we can, start the next lookup in the queue running.
 * This assumes that the lookup on the head of the queue hasn't been
 * started yet.  It also removes the lookup from the head of the queue,
 * setting the current_lookup pointer pointing to it.
 */
void
start_lookup(void) {
    debug("start_lookup()");
    if (cancel_now)
        return;

    /*
     * If there's a current lookup running, we really shouldn't get
     * here.
     */
    INSIST(current_lookup == NULL);

    current_lookup = ISC_LIST_HEAD(lookup_list);
    /*
     * Put the current lookup somewhere so cancel_all can find it
     */
    if (current_lookup != NULL) {
        ISC_LIST_DEQUEUE(lookup_list, current_lookup, link);
        setup_lookup(current_lookup);
        do_lookup(current_lookup);
    } else {
        check_if_done();
    }
}

/*
 * If we can, clear the current lookup and start the next one running.
 * This calls try_clear_lookup, so may invalidate the lookup pointer.
 */
static void
check_next_lookup(dig_lookup_t *lookup) {

    INSIST(!free_now);

    debug("check_next_lookup(%p)", lookup);

    if (ISC_LIST_HEAD(lookup->q) != NULL) {
        debug("still have a worker");
        return;
    }
    if (try_clear_lookup(lookup)) {
        current_lookup = NULL;
        start_lookup();
    }
}

/*
 * Create and queue a new lookup as a followup to the current lookup,
 * based on the supplied message and section.  This is used in trace and
 * name server search modes to start a new lookup using servers from
 * NS records in a reply. Returns the number of followup lookups made.
 */
static int
followup_lookup(dns_message_t *msg, dig_query_t *query, dns_section_t section)
{
    dig_lookup_t *lookup = NULL;
    dig_server_t *srv = NULL;
    dns_rdataset_t *rdataset = NULL;
    dns_rdata_t rdata = DNS_RDATA_INIT;
    dns_name_t *name = NULL;
    isc_result_t result;
    isc_boolean_t success = ISC_FALSE;
    int numLookups = 0;

    INSIST(!free_now);

    debug("following up %s", query->lookup->textname);

    for (result = dns_message_firstname(msg, section);
         result == ISC_R_SUCCESS;
         result = dns_message_nextname(msg, section))
    {
        name = NULL;
        dns_message_currentname(msg, section, &name);

        rdataset = NULL;
        result = dns_message_findtype(name, dns_rdatatype_ns, 0,
                          &rdataset);
        if (result != ISC_R_SUCCESS)
            continue;

        debug("found NS set");

        for (result = dns_rdataset_first(rdataset);
             result == ISC_R_SUCCESS;
             result = dns_rdataset_next(rdataset))
        {
            char namestr[DNS_NAME_FORMATSIZE];
            dns_rdata_ns_t ns;

            if (query->lookup->trace_root &&
                query->lookup->nsfound >= MXSERV)
                break;

            dns_rdataset_current(rdataset, &rdata);

            query->lookup->nsfound++;
            (void)dns_rdata_tostruct(&rdata, &ns, NULL);
            dns_name_format(&ns.name, namestr, sizeof(namestr));
            dns_rdata_freestruct(&ns);

            /* Initialize lookup if we've not yet */
            debug("found NS %d %s", numLookups, namestr);
            numLookups++;
            if (!success) {
                success = ISC_TRUE;
                lookup_counter++;
                lookup = requeue_lookup(query->lookup,
                            ISC_FALSE);
                cancel_lookup(query->lookup);
                lookup->doing_xfr = ISC_FALSE;
                if (!lookup->trace_root &&
                    section == DNS_SECTION_ANSWER)
                    lookup->trace = ISC_FALSE;
                else
                    lookup->trace = query->lookup->trace;
                lookup->ns_search_only =
                    query->lookup->ns_search_only;
                lookup->trace_root = ISC_FALSE;
            }
            srv = make_server(namestr);
            debug("adding server %s", srv->servername);
            ISC_LIST_APPEND(lookup->my_server_list, srv, link);
            dns_rdata_reset(&rdata);
        }
    }

    if (lookup == NULL &&
        section == DNS_SECTION_ANSWER &&
        (query->lookup->trace || query->lookup->ns_search_only))
        return (followup_lookup(msg, query, DNS_SECTION_AUTHORITY));

    return numLookups;
}

/*
 * Create and queue a new lookup using the next origin from the search
 * list, read in setup_system().
 *
 * Return ISC_TRUE iff there was another searchlist entry.
 */
static isc_boolean_t
next_origin(dns_message_t *msg, dig_query_t *query) {
    dig_lookup_t *lookup;

    UNUSED(msg);

    INSIST(!free_now);

    debug("next_origin()");
    debug("following up %s", query->lookup->textname);

    if (!usesearch)
        /*
         * We're not using a search list, so don't even think
         * about finding the next entry.
         */
        return (ISC_FALSE);
    if (query->lookup->origin == NULL)
        /*
         * Then we just did rootorg; there's nothing left.
         */
        return (ISC_FALSE);
    lookup = requeue_lookup(query->lookup, ISC_TRUE);
    lookup->origin = ISC_LIST_NEXT(query->lookup->origin, link);
    cancel_lookup(query->lookup);
    return (ISC_TRUE);
}

/*
 * Insert an SOA record into the sendmessage in a lookup.  Used for
 * creating IXFR queries.
 */
static void
insert_soa(dig_lookup_t *lookup) {
    isc_result_t result;
    dns_rdata_soa_t soa;
    dns_rdata_t *rdata = NULL;
    dns_rdatalist_t *rdatalist = NULL;
    dns_rdataset_t *rdataset = NULL;
    dns_name_t *soaname = NULL;

    debug("insert_soa()");
    soa.mctx = mctx;
    soa.serial = lookup->ixfr_serial;
    soa.refresh = 0;
    soa.retry = 0;
    soa.expire = 0;
    soa.minimum = 0;
    soa.common.rdclass = lookup->rdclass;
    soa.common.rdtype = dns_rdatatype_soa;

    dns_name_init(&soa.origin, NULL);
    dns_name_init(&soa.contact, NULL);

    dns_name_clone(dns_rootname, &soa.origin);
    dns_name_clone(dns_rootname, &soa.contact);

    isc_buffer_init(&lookup->rdatabuf, lookup->rdatastore,
            sizeof(lookup->rdatastore));

    result = dns_message_gettemprdata(lookup->sendmsg, &rdata);
    check_result(result, "dns_message_gettemprdata");

    result = dns_rdata_fromstruct(rdata, lookup->rdclass,
                      dns_rdatatype_soa, &soa,
                      &lookup->rdatabuf);
    check_result(result, "isc_rdata_fromstruct");

    result = dns_message_gettemprdatalist(lookup->sendmsg, &rdatalist);
    check_result(result, "dns_message_gettemprdatalist");

    result = dns_message_gettemprdataset(lookup->sendmsg, &rdataset);
    check_result(result, "dns_message_gettemprdataset");

    dns_rdatalist_init(rdatalist);
    rdatalist->type = dns_rdatatype_soa;
    rdatalist->rdclass = lookup->rdclass;
    rdatalist->covers = 0;
    rdatalist->ttl = 0;
    ISC_LIST_INIT(rdatalist->rdata);
    ISC_LIST_APPEND(rdatalist->rdata, rdata, link);

    dns_rdataset_init(rdataset);
    dns_rdatalist_tordataset(rdatalist, rdataset);

    result = dns_message_gettempname(lookup->sendmsg, &soaname);
    check_result(result, "dns_message_gettempname");
    dns_name_init(soaname, NULL);
    dns_name_clone(lookup->name, soaname);
    ISC_LIST_INIT(soaname->list);
    ISC_LIST_APPEND(soaname->list, rdataset, link);
    dns_message_addname(lookup->sendmsg, soaname, DNS_SECTION_AUTHORITY);
}

/*
 * Setup the supplied lookup structure, making it ready to start sending
 * queries to servers.  Create and initialize the message to be sent as
 * well as the query structures and buffer space for the replies.  If the
 * server list is empty, clone it from the system default list.
 */
void
setup_lookup(dig_lookup_t *lookup) {
    isc_result_t result;
    int len;
    dig_server_t *serv;
    dig_query_t *query;
    isc_buffer_t b;
    dns_compress_t cctx;
    char store[MXNAME];

    REQUIRE(lookup != NULL);
    INSIST(!free_now);

    debug("setup_lookup(%p)", lookup);

    result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
                    &lookup->sendmsg);
    check_result(result, "dns_message_create");

    if (lookup->new_search) {
        debug("resetting lookup counter.");
        lookup_counter = 0;
    }

    if (ISC_LIST_EMPTY(lookup->my_server_list)) {
        debug("cloning server list");
        clone_server_list(server_list, &lookup->my_server_list);
    }
    result = dns_message_gettempname(lookup->sendmsg, &lookup->name);
    check_result(result, "dns_message_gettempname");
    dns_name_init(lookup->name, NULL);

    isc_buffer_init(&lookup->namebuf, lookup->namespace,
            sizeof(lookup->namespace));
    isc_buffer_init(&lookup->onamebuf, lookup->onamespace,
            sizeof(lookup->onamespace));

    /*
     * If the name has too many dots, force the origin to be NULL
     * (which produces an absolute lookup).  Otherwise, take the origin
     * we have if there's one in the struct already.  If it's NULL,
     * take the first entry in the searchlist iff either usesearch
     * is TRUE or we got a domain line in the resolv.conf file.
     */
    /* XXX New search here? */
    if ((count_dots(lookup->textname) >= ndots) || !usesearch)
        lookup->origin = NULL; /* Force abs lookup */
    else if (lookup->origin == NULL && lookup->new_search && usesearch) {
        lookup->origin = ISC_LIST_HEAD(search_list);
    }
    if (lookup->origin != NULL) {
        debug("trying origin %s", lookup->origin->origin);
        result = dns_message_gettempname(lookup->sendmsg,
                         &lookup->oname);
        check_result(result, "dns_message_gettempname");
        dns_name_init(lookup->oname, NULL);
        /* XXX Helper funct to conv char* to name? */
        len = strlen(lookup->origin->origin);
        isc_buffer_init(&b, lookup->origin->origin, len);
        isc_buffer_add(&b, len);
        result = dns_name_fromtext(lookup->oname, &b, dns_rootname,
                       ISC_FALSE, &lookup->onamebuf);
        if (result != ISC_R_SUCCESS) {
            dns_message_puttempname(lookup->sendmsg,
                        &lookup->name);
            dns_message_puttempname(lookup->sendmsg,
                        &lookup->oname);
            fatal("'%s' is not in legal name syntax (%s)",
                  lookup->origin->origin,
                  isc_result_totext(result));
        }
        if (lookup->trace && lookup->trace_root) {
            dns_name_clone(dns_rootname, lookup->name);
        } else {
            len = strlen(lookup->textname);
            isc_buffer_init(&b, lookup->textname, len);
            isc_buffer_add(&b, len);
            result = dns_name_fromtext(lookup->name, &b,
                           lookup->oname, ISC_FALSE,
                           &lookup->namebuf);
        }
        if (result != ISC_R_SUCCESS) {
            dns_message_puttempname(lookup->sendmsg,
                        &lookup->name);
            dns_message_puttempname(lookup->sendmsg,
                        &lookup->oname);
            fatal("'%s' is not in legal name syntax (%s)",
                  lookup->textname, isc_result_totext(result));
        }
        dns_message_puttempname(lookup->sendmsg, &lookup->oname);
    } else {
        debug("using root origin");
        if (lookup->trace && lookup->trace_root)
            dns_name_clone(dns_rootname, lookup->name);
        else {
            len = strlen(lookup->textname);
            isc_buffer_init(&b, lookup->textname, len);
            isc_buffer_add(&b, len);
            result = dns_name_fromtext(lookup->name, &b,
                           dns_rootname,
                           ISC_FALSE,
                           &lookup->namebuf);
        }
        if (result != ISC_R_SUCCESS) {
            dns_message_puttempname(lookup->sendmsg,
                        &lookup->name);
            isc_buffer_init(&b, store, MXNAME);
            fatal("'%s' is not a legal name "
                  "(%s)", lookup->textname,
                  isc_result_totext(result));
        }
    }
    dns_name_format(lookup->name, store, sizeof(store));
    trying(store, lookup);
    INSIST(dns_name_isabsolute(lookup->name));

    lookup->sendmsg->id = (unsigned short)(random() & 0xFFFF);
    lookup->sendmsg->opcode = dns_opcode_query;
    lookup->msgcounter = 0;
    /*
     * If this is a trace request, completely disallow recursion, since
     * it's meaningless for traces.
     */
    if (lookup->trace || (lookup->ns_search_only && !lookup->trace_root))
        lookup->recurse = ISC_FALSE;

    if (lookup->recurse &&
        lookup->rdtype != dns_rdatatype_axfr &&
        lookup->rdtype != dns_rdatatype_ixfr) {
        debug("recursive query");
        lookup->sendmsg->flags |= DNS_MESSAGEFLAG_RD;
    }

    /* XXX aaflag */
    if (lookup->aaonly) {
        debug("AA query");
        lookup->sendmsg->flags |= DNS_MESSAGEFLAG_AA;
    }

    if (lookup->adflag) {
        debug("AD query");
        lookup->sendmsg->flags |= DNS_MESSAGEFLAG_AD;
    }

    if (lookup->cdflag) {
        debug("CD query");
        lookup->sendmsg->flags |= DNS_MESSAGEFLAG_CD;
    }

    dns_message_addname(lookup->sendmsg, lookup->name,
                DNS_SECTION_QUESTION);

    if (lookup->trace && lookup->trace_root) {
        lookup->qrdtype = lookup->rdtype;
        lookup->rdtype = dns_rdatatype_ns;
    }

    if ((lookup->rdtype == dns_rdatatype_axfr) ||
        (lookup->rdtype == dns_rdatatype_ixfr)) {
        lookup->doing_xfr = ISC_TRUE;
        /*
         * Force TCP mode if we're doing an xfr.
         * XXX UDP ixfr's would be useful
         */
        lookup->tcp_mode = ISC_TRUE;
    }

    add_question(lookup->sendmsg, lookup->name, lookup->rdclass,
             lookup->rdtype);

    /* add_soa */
    if (lookup->rdtype == dns_rdatatype_ixfr)
        insert_soa(lookup);

    /* XXX Insist this? */
    lookup->tsigctx = NULL;
    lookup->querysig = NULL;
    if (key != NULL) {
        debug("initializing keys");
        result = dns_message_settsigkey(lookup->sendmsg, key);
        check_result(result, "dns_message_settsigkey");
    }

    lookup->sendspace = isc_mempool_get(commctx);
    if (lookup->sendspace == NULL)
        fatal("memory allocation failure");

    result = dns_compress_init(&cctx, -1, mctx);
    check_result(result, "dns_compress_init");

    debug("starting to render the message");
    isc_buffer_init(&lookup->sendbuf, lookup->sendspace, COMMSIZE);
    result = dns_message_renderbegin(lookup->sendmsg, &cctx,
                     &lookup->sendbuf);
    check_result(result, "dns_message_renderbegin");
    if (lookup->udpsize > 0 || lookup->dnssec) {
        if (lookup->udpsize == 0)
            lookup->udpsize = 2048;
        add_opt(lookup->sendmsg, lookup->udpsize, lookup->dnssec);
    }

    result = dns_message_rendersection(lookup->sendmsg,
                       DNS_SECTION_QUESTION, 0);
    check_result(result, "dns_message_rendersection");
    result = dns_message_rendersection(lookup->sendmsg,
                       DNS_SECTION_AUTHORITY, 0);
    check_result(result, "dns_message_rendersection");
    result = dns_message_renderend(lookup->sendmsg);
    check_result(result, "dns_message_renderend");
    debug("done rendering");

    dns_compress_invalidate(&cctx);

    /*
     * Force TCP mode if the request is larger than 512 bytes.
     */
    if (isc_buffer_usedlength(&lookup->sendbuf) > 512)
        lookup->tcp_mode = ISC_TRUE;

    lookup->pending = ISC_FALSE;

    for (serv = ISC_LIST_HEAD(lookup->my_server_list);
         serv != NULL;
         serv = ISC_LIST_NEXT(serv, link)) {
        query = isc_mem_allocate(mctx, sizeof(dig_query_t));
        if (query == NULL)
            fatal("memory allocation failure in %s:%d",
                  __FILE__, __LINE__);
        debug("create query %p linked to lookup %p",
               query, lookup);
        query->lookup = lookup;
        query->waiting_connect = ISC_FALSE;
        query->recv_made = ISC_FALSE;
        query->first_pass = ISC_TRUE;
        query->first_soa_rcvd = ISC_FALSE;
        query->second_rr_rcvd = ISC_FALSE;
        query->first_repeat_rcvd = ISC_FALSE;
        query->first_rr_serial = 0;
        query->second_rr_serial = 0;
        query->servname = serv->servername;
        query->rr_count = 0;
        ISC_LINK_INIT(query, link);
        ISC_LIST_INIT(query->recvlist);
        ISC_LIST_INIT(query->lengthlist);
        query->sock = NULL;
        query->recvspace = isc_mempool_get(commctx);
        if (query->recvspace == NULL)
            fatal("memory allocation failure");

        isc_buffer_init(&query->recvbuf, query->recvspace, COMMSIZE);
        isc_buffer_init(&query->lengthbuf, query->lengthspace, 2);
        isc_buffer_init(&query->slbuf, query->slspace, 2);

        ISC_LINK_INIT(query, link);
        ISC_LIST_ENQUEUE(lookup->q, query, link);
    }
    /* XXX qrflag, print_query, etc... */
    if (!ISC_LIST_EMPTY(lookup->q) && qr) {
        printmessage(ISC_LIST_HEAD(lookup->q), lookup->sendmsg,
                 ISC_TRUE);
    }
}

/*
 * Event handler for send completion.  Track send counter, and clear out
 * the query if the send was canceled.
 */
static void
send_done(isc_task_t *_task, isc_event_t *event) {
    REQUIRE(event->ev_type == ISC_SOCKEVENT_SENDDONE);

    UNUSED(_task);

    LOCK_LOOKUP;

    isc_event_free(&event);

    debug("send_done()");
    sendcount--;
    debug("sendcount=%d", sendcount);
    INSIST(sendcount >= 0);
    check_if_done();
    UNLOCK_LOOKUP;
}

/*
 * Cancel a lookup, sending isc_socket_cancel() requests to all outstanding
 * IO sockets.  The cancel handlers should take care of cleaning up the
 * query and lookup structures
 */
static void
cancel_lookup(dig_lookup_t *lookup) {
    dig_query_t *query, *next;

    debug("cancel_lookup()");
    query = ISC_LIST_HEAD(lookup->q);
    while (query != NULL) {
        next = ISC_LIST_NEXT(query, link);
        if (query->sock != NULL) {
            isc_socket_cancel(query->sock, global_task,
                      ISC_SOCKCANCEL_ALL);
            check_if_done();
        } else {
            clear_query(query);
        }
        query = next;
    }
    if (lookup->timer != NULL)
        isc_timer_detach(&lookup->timer);
    lookup->pending = ISC_FALSE;
    lookup->retries = 0;
}

static void
bringup_timer(dig_query_t *query, unsigned int default_timeout) {
    dig_lookup_t *l;
    unsigned int local_timeout;
    isc_result_t result;

    debug("bringup_timer()");
    /*
     * If the timer already exists, that means we're calling this
     * a second time (for a retry).  Don't need to recreate it,
     * just reset it.
     */
    l = query->lookup;
    if (ISC_LIST_NEXT(query, link) != NULL)
        local_timeout = SERVER_TIMEOUT;
    else {
        if (timeout == 0) {
            local_timeout = default_timeout;
        } else
            local_timeout = timeout;
    }
    debug("have local timeout of %d", local_timeout);
    isc_interval_set(&l->interval, local_timeout, 0);
    if (l->timer != NULL)
        isc_timer_detach(&l->timer);
    result = isc_timer_create(timermgr,
                  isc_timertype_once,
                  NULL,
                  &l->interval,
                  global_task,
                  connect_timeout,
                  l, &l->timer);
    check_result(result, "isc_timer_create");
}

static void
connect_done(isc_task_t *task, isc_event_t *event);

/*
 * Unlike send_udp, this can't be called multiple times with the same
 * query.  When we retry TCP, we requeue the whole lookup, which should
 * start anew.
 */
static void
send_tcp_connect(dig_query_t *query) {
    isc_result_t result;
    dig_query_t *next;
    dig_lookup_t *l;

    debug("send_tcp_connect(%p)", query);

    l = query->lookup;
    query->waiting_connect = ISC_TRUE;
    query->lookup->current_query = query;
    get_address(query->servname, port, &query->sockaddr);

    if (specified_source &&
        (isc_sockaddr_pf(&query->sockaddr) !=
         isc_sockaddr_pf(&bind_address))) {
        printf(";; Skipping server %s, incompatible "
               "address family\n", query->servname);
        query->waiting_connect = ISC_FALSE;
        next = ISC_LIST_NEXT(query, link);
        l = query->lookup;
        clear_query(query);
        if (next == NULL) {
            printf(";; No acceptable nameservers\n");
            check_next_lookup(l);
            return;
        }
        send_tcp_connect(next);
        return;
    }
    INSIST(query->sock == NULL);
    result = isc_socket_create(socketmgr,
                   isc_sockaddr_pf(&query->sockaddr),
                   isc_sockettype_tcp, &query->sock);
    check_result(result, "isc_socket_create");
    sockcount++;
    debug("sockcount=%d", sockcount);
    if (specified_source)
        result = isc_socket_bind(query->sock, &bind_address);
    else {
        if ((isc_sockaddr_pf(&query->sockaddr) == AF_INET) &&
            have_ipv4)
            isc_sockaddr_any(&bind_any);
        else
            isc_sockaddr_any6(&bind_any);
        result = isc_socket_bind(query->sock, &bind_any);
    }
    check_result(result, "isc_socket_bind");
    bringup_timer(query, TCP_TIMEOUT);
    result = isc_socket_connect(query->sock, &query->sockaddr,
                    global_task, connect_done, query);
    check_result(result, "isc_socket_connect");
    /*
     * If we're at the endgame of a nameserver search, we need to
     * immediately bring up all the queries.  Do it here.
     */
    if (l->ns_search_only && !l->trace_root) {
        debug("sending next, since searching");
        next = ISC_LIST_NEXT(query, link);
        if (next != NULL)
            send_tcp_connect(next);
    }
}

/*
 * Send a UDP packet to the remote nameserver, possible starting the
 * recv action as well.  Also make sure that the timer is running and
 * is properly reset.
 */
static void
send_udp(dig_query_t *query) {
    dig_lookup_t *l = NULL;
    dig_query_t *next;
    isc_result_t result;

    debug("send_udp(%p)", query);

    l = query->lookup;
    bringup_timer(query, UDP_TIMEOUT);
    l->current_query = query;
    debug("working on lookup %p, query %p",
          query->lookup, query);
    if (!query->recv_made) {
        /* XXX Check the sense of this, need assertion? */
        query->waiting_connect = ISC_FALSE;
        get_address(query->servname, port, &query->sockaddr);

        result = isc_socket_create(socketmgr,
                       isc_sockaddr_pf(&query->sockaddr),
                       isc_sockettype_udp, &query->sock);
        check_result(result, "isc_socket_create");
        sockcount++;
        debug("sockcount=%d", sockcount);
        if (specified_source) {
            result = isc_socket_bind(query->sock, &bind_address);
        } else {
            isc_sockaddr_anyofpf(&bind_any,
                    isc_sockaddr_pf(&query->sockaddr));
            result = isc_socket_bind(query->sock, &bind_any);
        }
        check_result(result, "isc_socket_bind");

        query->recv_made = ISC_TRUE;
        ISC_LINK_INIT(&query->recvbuf, link);
        ISC_LIST_ENQUEUE(query->recvlist, &query->recvbuf,
                 link);
        debug("recving with lookup=%p, query=%p, sock=%p",
              query->lookup, query,
              query->sock);
        result = isc_socket_recvv(query->sock,
                      &query->recvlist, 1,
                      global_task, recv_done,
                      query);
        check_result(result, "isc_socket_recvv");
        recvcount++;
        debug("recvcount=%d", recvcount);
    }
    ISC_LIST_INIT(query->sendlist);
    ISC_LINK_INIT(&l->sendbuf, link);
    ISC_LIST_ENQUEUE(query->sendlist, &l->sendbuf,
             link);
    debug("sending a request");
    TIME_NOW(&query->time_sent);
    INSIST(query->sock != NULL);
    result = isc_socket_sendtov(query->sock, &query->sendlist,
                    global_task, send_done, query,
                    &query->sockaddr, NULL);
    check_result(result, "isc_socket_sendtov");
    sendcount++;
    /*
     * If we're at the endgame of a nameserver search, we need to
     * immediately bring up all the queries.  Do it here.
     */
    if (l->ns_search_only && !l->trace_root) {
        debug("sending next, since searching");
        next = ISC_LIST_NEXT(query, link);
        if (next != NULL)
            send_udp(next);
    }
}

/*
 * IO timeout handler, used for both connect and recv timeouts.  If
 * retries are still allowed, either resend the UDP packet or queue a
 * new TCP lookup.  Otherwise, cancel the lookup.
 */
static void
connect_timeout(isc_task_t *task, isc_event_t *event) {
    dig_lookup_t *l = NULL;
    dig_query_t *query = NULL, *cq;

    UNUSED(task);
    REQUIRE(event->ev_type == ISC_TIMEREVENT_IDLE);

    debug("connect_timeout()");

    LOCK_LOOKUP;
    l = event->ev_arg;
    query = l->current_query;
    isc_event_free(&event);

    INSIST(!free_now);

    if ((query != NULL) && (query->lookup->current_query != NULL) &&
        (ISC_LIST_NEXT(query->lookup->current_query, link) != NULL)) {
        debug("trying next server...");
        cq = query->lookup->current_query;
        if (!l->tcp_mode)
            send_udp(ISC_LIST_NEXT(cq, link));
        else
            send_tcp_connect(ISC_LIST_NEXT(cq, link));
        UNLOCK_LOOKUP;
        return;
    }

    if (l->retries > 1) {
        if (!l->tcp_mode) {
            l->retries--;
            debug("resending UDP request to first server");
            send_udp(ISC_LIST_HEAD(l->q));
        } else {
            debug("making new TCP request, %d tries left",
                  l->retries);
            l->retries--;
            requeue_lookup(l, ISC_TRUE);
            cancel_lookup(l);
        }
    } else {
        fputs(l->cmdline, stdout);
        printf(";; connection timed out; no servers could be "
               "reached\n");
        cancel_lookup(l);
        if (exitcode < 9)
            exitcode = 9;
    }
    UNLOCK_LOOKUP;
}

/*
 * Event handler for the TCP recv which gets the length header of TCP
 * packets.  Start the next recv of length bytes.
 */
static void
tcp_length_done(isc_task_t *task, isc_event_t *event) {
    isc_socketevent_t *sevent;
    isc_buffer_t *b = NULL;
    isc_result_t result;
    dig_query_t *query = NULL;
    dig_lookup_t *l;
    isc_uint16_t length;

    REQUIRE(event->ev_type == ISC_SOCKEVENT_RECVDONE);
    INSIST(!free_now);

    UNUSED(task);

    debug("tcp_length_done()");

    LOCK_LOOKUP;
    sevent = (isc_socketevent_t *)event;
    query = event->ev_arg;

    recvcount--;
    INSIST(recvcount >= 0);

    if (sevent->result == ISC_R_CANCELED) {
        isc_event_free(&event);
        l = query->lookup;
        clear_query(query);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }
    if (sevent->result != ISC_R_SUCCESS) {
        char sockstr[ISC_SOCKADDR_FORMATSIZE];
        isc_sockaddr_format(&query->sockaddr, sockstr,
                    sizeof(sockstr));
        printf(";; communications error to %s: %s\n",
               sockstr, isc_result_totext(sevent->result));
        l = query->lookup;
        isc_socket_detach(&query->sock);
        sockcount--;
        debug("sockcount=%d", sockcount);
        INSIST(sockcount >= 0);
        isc_event_free(&event);
        clear_query(query);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }
    b = ISC_LIST_HEAD(sevent->bufferlist);
    ISC_LIST_DEQUEUE(sevent->bufferlist, &query->lengthbuf, link);
    length = isc_buffer_getuint16(b);
    if (length == 0) {
        isc_event_free(&event);
        launch_next_query(query, ISC_FALSE);
        UNLOCK_LOOKUP;
        return;
    }

    /*
     * Even though the buffer was already init'ed, we need
     * to redo it now, to force the length we want.
     */
    isc_buffer_invalidate(&query->recvbuf);
    isc_buffer_init(&query->recvbuf, query->recvspace, length);
    ENSURE(ISC_LIST_EMPTY(query->recvlist));
    ISC_LINK_INIT(&query->recvbuf, link);
    ISC_LIST_ENQUEUE(query->recvlist, &query->recvbuf, link);
    debug("recving with lookup=%p, query=%p",
           query->lookup, query);
    result = isc_socket_recvv(query->sock, &query->recvlist, length, task,
                  recv_done, query);
    check_result(result, "isc_socket_recvv");
    recvcount++;
    debug("resubmitted recv request with length %d, recvcount=%d",
          length, recvcount);
    isc_event_free(&event);
    UNLOCK_LOOKUP;
}

/*
 * For transfers that involve multiple recvs (XFR's in particular),
 * launch the next recv.
 */
static void
launch_next_query(dig_query_t *query, isc_boolean_t include_question) {
    isc_result_t result;
    dig_lookup_t *l;

    INSIST(!free_now);

    debug("launch_next_query()");

    if (!query->lookup->pending) {
        debug("ignoring launch_next_query because !pending");
        isc_socket_detach(&query->sock);
        sockcount--;
        debug("sockcount=%d", sockcount);
        INSIST(sockcount >= 0);
        query->waiting_connect = ISC_FALSE;
        l = query->lookup;
        clear_query(query);
        check_next_lookup(l);
        return;
    }

    isc_buffer_clear(&query->slbuf);
    isc_buffer_clear(&query->lengthbuf);
    isc_buffer_putuint16(&query->slbuf, (isc_uint16_t) query->lookup->sendbuf.used);
    ISC_LIST_INIT(query->sendlist);
    ISC_LINK_INIT(&query->slbuf, link);
    ISC_LIST_ENQUEUE(query->sendlist, &query->slbuf, link);
    if (include_question) {
        ISC_LINK_INIT(&query->lookup->sendbuf, link);
        ISC_LIST_ENQUEUE(query->sendlist, &query->lookup->sendbuf,
                 link);
    }
    ISC_LINK_INIT(&query->lengthbuf, link);
    ISC_LIST_ENQUEUE(query->lengthlist, &query->lengthbuf, link);

    result = isc_socket_recvv(query->sock, &query->lengthlist, 0,
                  global_task, tcp_length_done, query);
    check_result(result, "isc_socket_recvv");
    recvcount++;
    debug("recvcount=%d",recvcount);
    if (!query->first_soa_rcvd) {
        debug("sending a request in launch_next_query");
        TIME_NOW(&query->time_sent);
        result = isc_socket_sendv(query->sock, &query->sendlist,
                      global_task, send_done, query);
        check_result(result, "isc_socket_sendv");
        sendcount++;
        debug("sendcount=%d", sendcount);
    }
    query->waiting_connect = ISC_FALSE;
#if 0
    check_next_lookup(query->lookup);
#endif
    return;
}

/*
 * Event handler for TCP connect complete.  Make sure the connection was
 * successful, then pass into launch_next_query to actually send the
 * question.
 */
static void
connect_done(isc_task_t *task, isc_event_t *event) {
    isc_socketevent_t *sevent = NULL;
    dig_query_t *query = NULL, *next;
    dig_lookup_t *l;

    UNUSED(task);

    REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
    INSIST(!free_now);

    debug("connect_done()");

    LOCK_LOOKUP;
    sevent = (isc_socketevent_t *)event;
    query = sevent->ev_arg;

    INSIST(query->waiting_connect);

    query->waiting_connect = ISC_FALSE;

    if (sevent->result == ISC_R_CANCELED) {
        debug("in cancel handler");
        isc_socket_detach(&query->sock);
        sockcount--;
        INSIST(sockcount >= 0);
        debug("sockcount=%d", sockcount);
        query->waiting_connect = ISC_FALSE;
        isc_event_free(&event);
        l = query->lookup;
        clear_query(query);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }
    if (sevent->result != ISC_R_SUCCESS) {
        char sockstr[ISC_SOCKADDR_FORMATSIZE];

        debug("unsuccessful connection: %s",
              isc_result_totext(sevent->result));
        isc_sockaddr_format(&query->sockaddr, sockstr,
                    sizeof(sockstr));
        if (sevent->result != ISC_R_CANCELED)
            printf(";; Connection to %s(%s) for %s failed: "
                   "%s.\n", sockstr,
                   query->servname, query->lookup->textname,
                   isc_result_totext(sevent->result));
        isc_socket_detach(&query->sock);
        sockcount--;
        INSIST(sockcount >= 0);
        /* XXX Clean up exitcodes */
        if (exitcode < 9)
            exitcode = 9;
        debug("sockcount=%d", sockcount);
        query->waiting_connect = ISC_FALSE;
        isc_event_free(&event);
        l = query->lookup;
        if (l->current_query != NULL)
            next = ISC_LIST_NEXT(l->current_query, link);
        else
            next = NULL;
        clear_query(query);
        if (next != NULL) {
            bringup_timer(next, TCP_TIMEOUT);
            send_tcp_connect(next);
        } else {
            check_next_lookup(l);
        }
        UNLOCK_LOOKUP;
        return;
    }
    launch_next_query(query, ISC_TRUE);
    isc_event_free(&event);
    UNLOCK_LOOKUP;
}

/*
 * Check if the ongoing XFR needs more data before it's complete, using
 * the semantics of IXFR and AXFR protocols.  Much of the complexity of
 * this routine comes from determining when an IXFR is complete.
 * ISC_FALSE means more data is on the way, and the recv has been issued.
 */
static isc_boolean_t
check_for_more_data(dig_query_t *query, dns_message_t *msg,
            isc_socketevent_t *sevent)
{
    dns_rdataset_t *rdataset = NULL;
    dns_rdata_t rdata = DNS_RDATA_INIT;
    dns_rdata_soa_t soa;
    isc_uint32_t serial;
    isc_result_t result;

    debug("check_for_more_data()");

    /*
     * By the time we're in this routine, we know we're doing
     * either an AXFR or IXFR.  If there's no second_rr_type,
     * then we don't yet know which kind of answer we got back
     * from the server.  Here, we're going to walk through the
     * rr's in the message, acting as necessary whenever we hit
     * an SOA rr.
     */

    result = dns_message_firstname(msg, DNS_SECTION_ANSWER);
    if (result != ISC_R_SUCCESS) {
        puts("; Transfer failed.");
        return (ISC_TRUE);
    }
    do {
        dns_name_t *name;
        name = NULL;
        dns_message_currentname(msg, DNS_SECTION_ANSWER,
                    &name);
        for (rdataset = ISC_LIST_HEAD(name->list);
             rdataset != NULL;
             rdataset = ISC_LIST_NEXT(rdataset, link)) {
            result = dns_rdataset_first(rdataset);
            if (result != ISC_R_SUCCESS)
                continue;
            do {
                query->rr_count++;
                dns_rdata_reset(&rdata);
                dns_rdataset_current(rdataset, &rdata);
                /*
                 * If this is the first rr, make sure
                 * it's an SOA
                 */
                if ((!query->first_soa_rcvd) &&
                    (rdata.type != dns_rdatatype_soa)) {
                    puts("; Transfer failed.  "
                         "Didn't start with "
                         "SOA answer.");
                    return (ISC_TRUE);
                }
                if ((!query->second_rr_rcvd) &&
                    (rdata.type != dns_rdatatype_soa)) {
                    query->second_rr_rcvd = ISC_TRUE;
                    query->second_rr_serial = 0;
                    debug("got the second rr as nonsoa");
                    continue;
                }

                /*
                 * If the record is anything except an SOA
                 * now, just continue on...
                 */
                if (rdata.type != dns_rdatatype_soa)
                    goto next_rdata;
                /* Now we have an SOA.  Work with it. */
                debug("got an SOA");
                (void)dns_rdata_tostruct(&rdata, &soa, NULL);
                serial = soa.serial;
                dns_rdata_freestruct(&soa);
                if (!query->first_soa_rcvd) {
                    query->first_soa_rcvd = ISC_TRUE;
                    query->first_rr_serial = serial;
                    debug("this is the first %d",
                           query->lookup->ixfr_serial);
                    if (query->lookup->ixfr_serial >=
                        serial)
                        goto doexit;
                    goto next_rdata;
                }
                if (query->lookup->rdtype ==
                    dns_rdatatype_axfr) {
                    debug("doing axfr, got second SOA");
                    goto doexit;
                }
                if (!query->second_rr_rcvd) {
                    if (query->first_rr_serial == serial) {
                        debug("doing ixfr, got "
                              "empty zone");
                        goto doexit;
                    }
                    debug("this is the second %d",
                           query->lookup->ixfr_serial);
                    query->second_rr_rcvd = ISC_TRUE;
                    query->second_rr_serial = serial;
                    goto next_rdata;
                }
                if (query->second_rr_serial == 0) {
                    /*
                     * If the second RR was a non-SOA
                     * record, and we're getting any
                     * other SOA, then this is an
                     * AXFR, and we're done.
                     */
                    debug("done, since axfr");
                    goto doexit;
                }
                /*
                 * If we get to this point, we're doing an
                 * IXFR and have to start really looking
                 * at serial numbers.
                 */
                if (query->first_rr_serial == serial) {
                    debug("got a match for ixfr");
                    if (!query->first_repeat_rcvd) {
                        query->first_repeat_rcvd =
                            ISC_TRUE;
                        goto next_rdata;
                    }
                    debug("done with ixfr");
                    goto doexit;
                }
                debug("meaningless soa %d", serial);
            next_rdata:
                result = dns_rdataset_next(rdataset);
            } while (result == ISC_R_SUCCESS);
        }
        result = dns_message_nextname(msg, DNS_SECTION_ANSWER);
    } while (result == ISC_R_SUCCESS);
    launch_next_query(query, ISC_FALSE);
    return (ISC_FALSE);
 doexit:
    received(sevent->n, &sevent->address, query);
    return (ISC_TRUE);
}

/*
 * Event handler for recv complete.  Perform whatever actions are necessary,
 * based on the specifics of the user's request.
 */
static void
recv_done(isc_task_t *task, isc_event_t *event) {
    isc_socketevent_t *sevent = NULL;
    dig_query_t *query = NULL;
    isc_buffer_t *b = NULL;
    dns_message_t *msg = NULL;
    isc_result_t result;
    dig_lookup_t *n, *l;
    isc_boolean_t docancel = ISC_FALSE;
    unsigned int parseflags;

    UNUSED(task);
    INSIST(!free_now);

    debug("recv_done()");

    LOCK_LOOKUP;
    recvcount--;
    debug("recvcount=%d", recvcount);
    INSIST(recvcount >= 0);

    query = event->ev_arg;
    debug("lookup=%p, query=%p", query->lookup, query);

    l = query->lookup;

    REQUIRE(event->ev_type == ISC_SOCKEVENT_RECVDONE);
    sevent = (isc_socketevent_t *)event;

    if ((l->tcp_mode) && (l->timer != NULL))
        isc_timer_touch(l->timer);
    if ((!l->pending && !l->ns_search_only) || cancel_now) {
        debug("no longer pending.  Got %s",
            isc_result_totext(sevent->result));
        query->waiting_connect = ISC_FALSE;

        isc_event_free(&event);
        clear_query(query);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }

    if (sevent->result != ISC_R_SUCCESS) {
        if (sevent->result == ISC_R_CANCELED) {
            debug("in recv cancel handler");
            query->waiting_connect = ISC_FALSE;
        } else {
            printf(";; communications error: %s\n",
                   isc_result_totext(sevent->result));
            isc_socket_detach(&query->sock);
            sockcount--;
            debug("sockcount=%d", sockcount);
            INSIST(sockcount >= 0);
        }
        isc_event_free(&event);
        clear_query(query);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }

    b = ISC_LIST_HEAD(sevent->bufferlist);
    ISC_LIST_DEQUEUE(sevent->bufferlist, &query->recvbuf, link);
    result = dns_message_create(mctx, DNS_MESSAGE_INTENTPARSE, &msg);
    check_result(result, "dns_message_create");

    if (key != NULL) {
        if (l->querysig == NULL) {
            debug("getting initial querysig");
            result = dns_message_getquerytsig(l->sendmsg, mctx,
                              &l->querysig);
            check_result(result, "dns_message_getquerytsig");
        }
        result = dns_message_setquerytsig(msg, l->querysig);
        check_result(result, "dns_message_setquerytsig");
        result = dns_message_settsigkey(msg, key);
        check_result(result, "dns_message_settsigkey");
        msg->tsigctx = l->tsigctx;
        l->tsigctx = NULL;
        if (l->msgcounter != 0)
            msg->tcp_continuation = 1;
        l->msgcounter++;
    }

    debug("before parse starts");
    parseflags = DNS_MESSAGEPARSE_PRESERVEORDER;
    if (l->besteffort) {
        parseflags |= DNS_MESSAGEPARSE_BESTEFFORT;
        parseflags |= DNS_MESSAGEPARSE_IGNORETRUNCATION;
    }
    result = dns_message_parse(msg, b, parseflags);
    if (result == DNS_R_RECOVERABLE) {
        printf(";; Warning: Message parser reports malformed "
               "message packet.\n");
        result = ISC_R_SUCCESS;
    }
    if (result != ISC_R_SUCCESS) {
        printf(";; Got bad packet: %s\n", isc_result_totext(result));
        hex_dump(b);
        query->waiting_connect = ISC_FALSE;
        dns_message_destroy(&msg);
        isc_event_free(&event);
        clear_query(query);
        cancel_lookup(l);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }
    if ((msg->flags & DNS_MESSAGEFLAG_TC) != 0
        && !l->ignore && !l->tcp_mode)
    {
        printf(";; Truncated, retrying in TCP mode.\n");
        n = requeue_lookup(l, ISC_TRUE);
        n->tcp_mode = ISC_TRUE;
        dns_message_destroy(&msg);
        isc_event_free(&event);
        clear_query(query);
        cancel_lookup(l);
        check_next_lookup(l);
        UNLOCK_LOOKUP;
        return;
    }
    if (msg->rcode == dns_rcode_servfail && !l->servfail_stops) {
        dig_query_t *next = ISC_LIST_NEXT(query, link);
        if (l->current_query == query)
            l->current_query = NULL;
        if (next != NULL) {
            debug("sending query %p\n", next);
            if (l->tcp_mode)
                send_tcp_connect(next);
            else
                send_udp(next);
        }
        /*
         * If our query is at the head of the list and there
         * is no next, we're the only one left, so fall
         * through to print the message.
         */
        if ((ISC_LIST_HEAD(l->q) != query) ||
            (ISC_LIST_NEXT(query, link) != NULL)) {
            printf(";; Got SERVFAIL reply from %s, "
                   "trying next server\n",
                   query->servname);
            clear_query(query);
            check_next_lookup(l);
            dns_message_destroy(&msg);
            isc_event_free(&event);
            UNLOCK_LOOKUP;
            return;
        }
    }

    if (key != NULL) {
        result = dns_tsig_verify(&query->recvbuf, msg, NULL, NULL);
        if (result != ISC_R_SUCCESS) {
            printf(";; Couldn't verify signature: %s\n",
                   isc_result_totext(result));
            validated = ISC_FALSE;
        }
        l->tsigctx = msg->tsigctx;
        msg->tsigctx = NULL;
        if (l->querysig != NULL) {
            debug("freeing querysig buffer %p", l->querysig);
            isc_buffer_free(&l->querysig);
        }
        result = dns_message_getquerytsig(msg, mctx, &l->querysig);
        check_result(result,"dns_message_getquerytsig");
    }

    debug("after parse");
    if (l->doing_xfr && l->xfr_q == NULL) {
        l->xfr_q = query;
        /*
         * Once we are in the XFR message, increase
         * the timeout to much longer, so brief network
         * outages won't cause the XFR to abort
         */
        if (timeout != INT_MAX && l->timer != NULL) {
            unsigned int local_timeout;

            if (timeout == 0) {
                if (l->tcp_mode)
                    local_timeout = TCP_TIMEOUT * 4;
                else
                    local_timeout = UDP_TIMEOUT * 4;
            } else {
                if (timeout < (INT_MAX / 4))
                    local_timeout = timeout * 4;
                else
                    local_timeout = INT_MAX;
            }
            debug("have local timeout of %d", local_timeout);
            isc_interval_set(&l->interval, local_timeout, 0);
            result = isc_timer_reset(l->timer,
                         isc_timertype_once,
                         NULL,
                         &l->interval,
                         ISC_FALSE);
            check_result(result, "isc_timer_reset");
        }
    }

    if (!l->doing_xfr || l->xfr_q == query) {
        if (msg->rcode != dns_rcode_noerror && l->origin != NULL) {
            if (!next_origin(msg, query)) {
                printmessage(query, msg, ISC_TRUE);
                received(b->used, &sevent->address, query);
            }
        } else if (!l->trace && !l->ns_search_only) {
            printmessage(query, msg, ISC_TRUE);
        } else if (l->trace) {
            int n = 0;
            int count = msg->counts[DNS_SECTION_ANSWER];

            debug("in TRACE code");
            if (!l->ns_search_only)
                printmessage(query, msg, ISC_TRUE);

            l->rdtype = l->qrdtype;
            if (l->trace_root || (l->ns_search_only && count > 0))
            {
                if (!l->trace_root)
                    l->rdtype = dns_rdatatype_soa;
                n = followup_lookup(msg, query,
                            DNS_SECTION_ANSWER);
                l->trace_root = ISC_FALSE;
            } else if (count == 0)
                n = followup_lookup(msg, query,
                            DNS_SECTION_AUTHORITY);
            if (n == 0)
                docancel = ISC_TRUE;
        } else {
            debug("in NSSEARCH code");

            if (l->trace_root) {
                /*
                 * This is the initial NS query.
                 */
                int n;

                l->rdtype = dns_rdatatype_soa;
                n = followup_lookup(msg, query,
                            DNS_SECTION_ANSWER);
                if (n == 0)
                    docancel = ISC_TRUE;
                l->trace_root = ISC_FALSE;
            } else
                printmessage(query, msg, ISC_TRUE);
        }
    }

    if (l->pending)
        debug("still pending.");
    if (l->doing_xfr) {
        if (query != l->xfr_q) {
            dns_message_destroy(&msg);
            isc_event_free(&event);
            query->waiting_connect = ISC_FALSE;
            UNLOCK_LOOKUP;
            return;
        }
        if (!docancel)
            docancel = check_for_more_data(query, msg, sevent);
        if (docancel) {
            dns_message_destroy(&msg);
            clear_query(query);
            cancel_lookup(l);
            check_next_lookup(l);
        }
    } else {
        if (msg->rcode == dns_rcode_noerror || l->origin == NULL)
            received(b->used, &sevent->address, query);
        if (!query->lookup->ns_search_only)
            query->lookup->pending = ISC_FALSE;
        if (!query->lookup->ns_search_only ||
            query->lookup->trace_root || docancel)
        {
            dns_message_destroy(&msg);
            cancel_lookup(l);
        }
        clear_query(query);
        check_next_lookup(l);
    }
    if (msg != NULL)
        dns_message_destroy(&msg);
    isc_event_free(&event);
    UNLOCK_LOOKUP;
}

/*
 * Turn a name into an address, using system-supplied routines.  This is
 * used in looking up server names, etc... and needs to use system-supplied
 * routines, since they may be using a non-DNS system for these lookups.
 */
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);
}

/*
 * Initiate either a TCP or UDP lookup
 */
void
do_lookup(dig_lookup_t *lookup) {

    REQUIRE(lookup != NULL);

    debug("do_lookup()");
    lookup->pending = ISC_TRUE;
    if (lookup->tcp_mode)
        send_tcp_connect(ISC_LIST_HEAD(lookup->q));
    else
        send_udp(ISC_LIST_HEAD(lookup->q));
}

/*
 * Start everything in action upon task startup.
 */
void
onrun_callback(isc_task_t *task, isc_event_t *event) {
    UNUSED(task);

    isc_event_free(&event);
    LOCK_LOOKUP;
    start_lookup();
    UNLOCK_LOOKUP;
}

/*
 * Make everything on the lookup queue go away.  Mainly used by the
 * SIGINT handler.
 */
void
cancel_all(void) {
    dig_lookup_t *l, *n;
    dig_query_t *q, *nq;

    debug("cancel_all()");

    LOCK_LOOKUP;
    if (free_now) {
        UNLOCK_LOOKUP;
        return;
    }
    cancel_now = ISC_TRUE;
    if (current_lookup != NULL) {
        if (current_lookup->timer != NULL)
            isc_timer_detach(&current_lookup->timer);
        q = ISC_LIST_HEAD(current_lookup->q);
        while (q != NULL) {
            debug("cancelling query %p, belonging to %p",
                  q, current_lookup);
            nq = ISC_LIST_NEXT(q, link);
            if (q->sock != NULL) {
                isc_socket_cancel(q->sock, NULL,
                          ISC_SOCKCANCEL_ALL);
            } else {
                clear_query(q);
            }
            q = nq;
        }
    }
    l = ISC_LIST_HEAD(lookup_list);
    while (l != NULL) {
        n = ISC_LIST_NEXT(l, link);
        ISC_LIST_DEQUEUE(lookup_list, l, link);
        try_clear_lookup(l);
        l = n;
    }
    UNLOCK_LOOKUP;
}

/*
 * Destroy all of the libs we are using, and get everything ready for a
 * clean shutdown.
 */
void
destroy_libs(void) {
    void *ptr;
    dig_server_t *s;

    debug("destroy_libs()");
    if (global_task != NULL) {
        debug("freeing task");
        isc_task_detach(&global_task);
    }
    /*
     * The taskmgr_destroy() call blocks until all events are cleared
     * from the task.
     */
    if (taskmgr != NULL) {
        debug("freeing taskmgr");
        isc_taskmgr_destroy(&taskmgr);
    }
    LOCK_LOOKUP;
    REQUIRE(sockcount == 0);
    REQUIRE(recvcount == 0);
    REQUIRE(sendcount == 0);

    INSIST(ISC_LIST_HEAD(lookup_list) == NULL);
    INSIST(current_lookup == NULL);
    INSIST(!free_now);

    free_now = ISC_TRUE;

    s = ISC_LIST_HEAD(server_list);
    while (s != NULL) {
        debug("freeing global server %p", s);
        ptr = s;
        s = ISC_LIST_NEXT(s, link);
        isc_mem_free(mctx, ptr);
    }
    clear_searchlist();
    if (commctx != NULL) {
        debug("freeing commctx");
        isc_mempool_destroy(&commctx);
    }
    if (socketmgr != NULL) {
        debug("freeing socketmgr");
        isc_socketmgr_destroy(&socketmgr);
    }
    if (timermgr != NULL) {
        debug("freeing timermgr");
        isc_timermgr_destroy(&timermgr);
    }
    if (key != NULL) {
        debug("freeing key %p", key);
        dns_tsigkey_detach(&key);
    }
    if (namebuf != NULL)
        isc_buffer_free(&namebuf);

    if (is_dst_up) {
        debug("destroy DST lib");
        dst_lib_destroy();
        is_dst_up = ISC_FALSE;
    }
    if (entp != NULL) {
        debug("detach from entropy");
        isc_entropy_detach(&entp);
    }

    UNLOCK_LOOKUP;
    DESTROYLOCK(&lookup_lock);
    if (memdebugging != 0)
        isc_mem_stats(mctx, stderr);
    if (mctx != NULL)
        isc_mem_destroy(&mctx);
}