bin/dig/dighost.c

	dighost.c revision df5503799f5d2609cc759a7a1f3274daeb728236
/*
 * Copyright (C) 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#include <config.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

extern int h_errno;

#include <isc/types.h>
#include <isc/app.h>
#include <isc/assertions.h>
#include <isc/error.h>
#include <isc/mem.h>
#include <isc/net.h>
#include <isc/netdb.h>
#include <isc/result.h>
#include <isc/sockaddr.h>
#include <isc/socket.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/time.h>
#include <isc/buffer.h>
#include <isc/list.h>
#include <isc/util.h>

#include <dns/types.h>
#include <dns/message.h>
#include <dns/name.h>
#include <dns/fixedname.h>
#include <dns/rdata.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdataclass.h>
#include <dns/rdatatype.h>
#include <dns/result.h>

#include <dig/dig.h>

ISC_LIST(dig_lookup_t) lookup_list;
ISC_LIST(dig_server_t) server_list;

isc_boolean_t tcp_mode = ISC_FALSE, recurse = ISC_TRUE, have_ipv6 = ISC_FALSE,
    free_now = ISC_TRUE;
in_port_t port;
unsigned int timeout;
isc_mem_t *mctx = NULL;
isc_taskmgr_t *taskmgr = NULL;
isc_task_t *task = NULL;
isc_timermgr_t *timermgr = NULL;
isc_socketmgr_t *socketmgr = NULL;
dns_messageid_t id;
dns_name_t rootorg;
char *rootspace[BUFSIZE];
isc_buffer_t rootbuf;
int sendcount = 0;

extern isc_boolean_t short_form;

static void
free_lists(void);

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

    isc_buffer_remainingregion(b, &r);

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


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

    va_start(args, format);
    vfprintf(stderr, format, args);
    va_end(args);
    fprintf(stderr, "\n");
    free_now = ISC_TRUE;
    free_lists();
    isc_app_finish();
    if (mctx != NULL)
        isc_mem_destroy(&mctx);

    exit(1);
}

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

isc_boolean_t
isclass(char *text) {
    /* Tests if a field is a class, without needing isc libs
       initialized.  This list will have to be manually kept in
       sync with what the libs support. */
    const char *classlist[] = {"in", "hs", "any"};
    const int numclasses = 3;
    int i;

    for (i = 0; i < numclasses; i++)
        if (strcasecmp(text, classlist[i]) == 0)
            return ISC_TRUE;

    return ISC_FALSE;
}

isc_boolean_t
istype(char *text) {
    /* Tests if a field is a type, without needing isc libs
       initialized.  This list will have to be manually kept in
       sync with what the libs support. */
    const char *typelist[] = {"a", "ns", "md", "mf", "cname",
                  "soa", "mb", "mg", "mr", "null",
                  "wks", "ptr", "hinfo", "minfo",
                  "mx", "txt", "rp", "afsdb",
                  "x25", "isdn", "rt", "nsap",
                  "nsap_ptr", "sig", "key", "px",
                  "gpos", "aaaa", "loc", "nxt",
                  "srv", "naptr", "kx", "cert",
                  "a6", "dname", "opt", "unspec",
                  "tkey", "tsig", "axfr"};
    const int numtypes = 41;
    int i;

    for (i = 0; i < numtypes; i++) {
        if (strcasecmp(text, typelist[i]) == 0)
            return ISC_TRUE;
    }
    return ISC_FALSE;
}


static void
setup_system(void) {
    char rcinput[MXNAME];
    FILE *fp;
    char *ptr;
    dig_server_t *srv;

    id = getpid() << 8;

    if (server_list.head == NULL) {
        fp = fopen (RESOLVCONF, "r");
        if (fp != NULL) {
            while (fgets(rcinput, MXNAME, fp) != 0) {
                ptr = strtok (rcinput, " \t");
                if (ptr != NULL &&
                    strcasecmp(ptr, "nameserver") == 0) {
                    ptr = strtok (NULL, " \t");
                    if (ptr != NULL) {
                        srv = isc_mem_allocate(mctx,
                            sizeof(struct dig_server));
                        if (srv == NULL)
                            fatal("Memory "
                                  "allocation "
                                  "failure.");
                            strncpy(srv->
                                servername,
                                ptr,
                                MXNAME - 1);
                            ISC_LIST_APPEND
                                (server_list,
                                 srv, link);
                    }
                }
            }
            fclose (fp);
        }
    }

    if (server_list.head == NULL) {
        srv = isc_mem_allocate(mctx, sizeof(dig_server_t));
        if (srv == NULL)
            fatal("Memory allocation failure");
        strcpy(srv->servername, "127.0.0.1");
        ISC_LIST_APPEND(server_list, srv, link);
    }
}

static void
setup_libs(void) {
    isc_result_t result;
    isc_buffer_t b;

    result = isc_app_start();
    check_result(result, "isc_app_start");

    result = isc_net_probeipv4();
    check_result(result, "isc_net_probeipv4");

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

    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, &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");
    isc_buffer_init(&b, ".", 1);
    isc_buffer_add(&b, 1);
    dns_name_init(&rootorg, NULL);
    isc_buffer_init(&rootbuf, rootspace, BUFSIZE);
    result = dns_name_fromtext(&rootorg, &b, NULL, ISC_FALSE, &rootbuf);
    check_result(result, "dns_name_fromtext");
}

static void
add_type(dns_message_t *message, dns_name_t *name, dns_rdataclass_t rdclass,
     dns_rdatatype_t rdtype)
{
    dns_rdataset_t *rdataset;
    isc_result_t result;

    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);
}

void
followup_lookup(dns_message_t *msg, dig_query_t *query) {
    dig_lookup_t *lookup = NULL;
    dig_server_t *srv = NULL;
    dns_rdataset_t *rdataset = NULL;
    dns_rdata_t rdata;
    dns_name_t *name = NULL;
    isc_result_t result, loopresult;
    isc_buffer_t *b = NULL;
    isc_region_t r;
    int len;

    result = dns_message_firstname (msg, DNS_SECTION_ANSWER);
    if (result != ISC_R_SUCCESS) {
#ifdef DEBUG
        printf ("Firstname returned %s\n",
            isc_result_totext(result));
#endif
                return;
    }

#ifdef DEBUG
    fprintf (stderr,"Following up %s\n", query->lookup->textname);
#endif

    for (;;) {
        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)) {
            loopresult = dns_rdataset_first(rdataset);
            while (loopresult == ISC_R_SUCCESS) {
                dns_rdataset_current(rdataset, &rdata);
                if (rdata.type == dns_rdatatype_ns) {
                    result = isc_buffer_allocate(mctx, &b,
                                     BUFSIZE);
                    check_result (result,
                              "isc_buffer_allocate");
                    result = dns_rdata_totext (&rdata,
                                   NULL,
                                   b);
                    check_result (result,
                              "dns_rdata_totext");
                    isc_buffer_usedregion(b, &r);
                    len = r.length-1;
                    if (len >= MXNAME)
                        len = MXNAME-1;
                /* Initialize lookup if we've not yet */
#ifdef DEBUG
                    fprintf (stderr, "Found NS %d %.*s\n",
                         (int)r.length, (int)r.length,
                         (char *)r.base);
#endif
                    lookup = isc_mem_allocate
                        (mctx,
                         sizeof(struct
                            dig_lookup));
                    if (lookup == NULL)
                        fatal ("Memory "
                               "allocation "
                               "failure.");
                    lookup->pending = ISC_FALSE;
                    strncpy (lookup->textname,
                         query->lookup->
                         textname, MXNAME);
                    strncpy (lookup->rttext,
                         query->lookup->
                         rttext, 32);
                    strncpy (lookup->rctext,
                         query->lookup->
                         rctext, 32);
                    lookup->namespace[0]=0;
                    lookup->sendspace[0]=0;
                    lookup->sendmsg=NULL;
                    lookup->name=NULL;
                    lookup->timer = NULL;
                    lookup->xfr_q = NULL;
                    lookup->doing_xfr = ISC_FALSE;
                    lookup->identify = ISC_TRUE;
                    lookup->ns_search_only =
                        ISC_FALSE;
                    lookup->use_my_server_list =
                        ISC_TRUE;
                    ISC_LIST_INIT(lookup->
                              my_server_list);
                    ISC_LIST_INIT(lookup->q);
                    srv = isc_mem_allocate (mctx,
                                sizeof(
                                struct
                                dig_server));
                    if (srv == NULL)
                        fatal("Memory allocation "
                              "failure.");
                    strncpy(srv->servername, r.base,
                        len);
                    srv->servername[len]=0;
                    ISC_LIST_APPEND
                        (lookup->my_server_list,
                         srv, link);
                    isc_buffer_free (&b);
                }
#ifdef DEBUG
                fprintf (stderr, "Before insertion, init@%ld "
                     "-> %ld, new@%ld "
                     "-> %ld\n",(long int)query->lookup,
                     (long int)query->lookup->link.next,
                     (long int)lookup, (long int)lookup->
                     link.next);
#endif
                ISC_LIST_INSERTAFTER(lookup_list, query->
                             lookup, lookup,
                             link);
#ifdef DEBUG
                fprintf (stderr, "After insertion, init -> "
                     "%ld, new = %ld, "
                     "new -> %ld\n",(long int)query->
                     lookup->link.next,
                     (long int)lookup, (long int)lookup->
                     link.next);
#endif
                loopresult = dns_rdataset_next(rdataset);
            }
        }
    result = dns_message_nextname (msg, DNS_SECTION_ANSWER);
    if (result != ISC_R_SUCCESS)
        break;
    }
    if (lookup == NULL)
        return; /* We didn't get a NS.  Just give up. */
}

void
setup_lookup(dig_lookup_t *lookup) {
    isc_result_t result;
    int len;
    dns_rdatatype_t rdtype;
    dns_rdataclass_t rdclass;
    dig_server_t *serv;
    dig_query_t *query;
    isc_textregion_t r;
    isc_buffer_t b;
    ISC_LIST(dig_server_t) *sl;

#ifdef DEBUG
    fprintf(stderr, "Setting up for looking up %s @%ld->%ld\n",
        lookup->textname, (long int)lookup,
        (long int)lookup->link.next);
#endif
    len=strlen(lookup->textname);
    isc_buffer_init(&b, lookup->textname, len);
    isc_buffer_add(&b, len);

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


    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, BUFSIZE);

    result = dns_name_fromtext(lookup->name, &b, &rootorg,
                    ISC_FALSE, &lookup->namebuf);
    if (result != ISC_R_SUCCESS) {
        dns_message_puttempname(lookup->sendmsg, &lookup->name);
        fatal("Aborting: %s is not a legal name syntax.",
              lookup->textname);
    }

    if (lookup->rctext[0] == 0)
        strcpy(lookup->rctext, "IN");
    if (lookup->rttext[0] == 0)
        strcpy(lookup->rttext, "A");

    lookup->sendmsg->id = id++;
    lookup->sendmsg->opcode = dns_opcode_query;
    if (recurse)
        lookup->sendmsg->flags |= DNS_MESSAGEFLAG_RD;

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


    if (!lookup->ns_search_only) {
        r.base=lookup->rttext;
        r.length=strlen(lookup->rttext);
    } else {
        r.base="NS";
        r.length=2;
    }
    result = dns_rdatatype_fromtext(&rdtype, &r);
    check_result(result, "dns_rdatatype_fromtext");
    if (rdtype == dns_rdatatype_axfr) {
        lookup->doing_xfr = ISC_TRUE;
        /*
         * Force TCP mode if we're doing an xfr.
         */
        tcp_mode = ISC_TRUE;
    }
    if (!lookup->ns_search_only) {
        r.base=lookup->rctext;
        r.length=strlen(lookup->rctext);
    } else {
        r.base="IN";
        r.length=2;
    }
    result = dns_rdataclass_fromtext(&rdclass, &r);
    check_result(result, "dns_rdataclass_fromtext");
    add_type(lookup->sendmsg, lookup->name, rdclass, rdtype);

    isc_buffer_init(&lookup->sendbuf, lookup->sendspace, COMMSIZE);
    result = dns_message_renderbegin(lookup->sendmsg, &lookup->sendbuf);
    check_result(result, "dns_message_renderbegin");
    result = dns_message_rendersection(lookup->sendmsg,
                       DNS_SECTION_QUESTION, 0);
    check_result(result, "dns_message_rendersection");
    result = dns_message_renderend(lookup->sendmsg);
    check_result(result, "dns_message_renderend");

    lookup->pending = ISC_FALSE;

    if (lookup->use_my_server_list)
        sl = &lookup->my_server_list;
    else
        sl = &server_list;
    for (serv = ISC_LIST_HEAD(*sl);
         serv != NULL;
         serv = ISC_LIST_NEXT(serv, link)) {
        query = isc_mem_allocate(mctx, sizeof(dig_query_t));
        if (query == NULL)
            fatal("Memory allocation failure.");
        query->lookup = lookup;
        query->working = ISC_FALSE;
        query->waiting_connect = ISC_FALSE;
        query->first_pass = ISC_TRUE;
        query->first_soa_rcvd = ISC_FALSE;
        query->servname = serv->servername;
        ISC_LIST_INIT(query->sendlist);
        ISC_LIST_INIT(query->recvlist);
        ISC_LIST_INIT(query->lengthlist);
        query->sock = NULL;

        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_LIST_ENQUEUE(lookup->q, query, link);
    }
}

static void
send_done(isc_task_t *task, isc_event_t *event) {
    UNUSED(task);
    isc_event_free(&event);
}

static void
cancel_lookup(dig_lookup_t *lookup) {
    dig_query_t *query;

#ifdef DEBUG
    fputs("Cancelling all queries\n", stderr);
#endif
    if (!lookup->pending)
        return;
    lookup->pending = ISC_FALSE;
    for (query = ISC_LIST_HEAD(lookup->q);
         query != NULL;
         query = ISC_LIST_NEXT(query, link)) {
        if (query->working) {
            isc_socket_cancel(query->sock, task,
                      ISC_SOCKCANCEL_ALL);
        }
    }
}

/* connect_timeout is used for both UDP recieves and TCP connects. */
static void
connect_timeout(isc_task_t *task, isc_event_t *event) {
    dig_lookup_t *lookup=NULL;
    dig_query_t *q=NULL;
    isc_result_t result;
    isc_buffer_t *b=NULL;
    isc_region_t r;

    lookup = event->ev_arg;

    REQUIRE(event->ev_type == ISC_TIMEREVENT_IDLE);

#ifdef DEBUG
    fputs ("Buffer Allocate connect_timeout\n",stderr);
#endif
    result = isc_buffer_allocate(mctx, &b, 256);
    check_result(result, "isc_buffer_allocate");
    for (q = ISC_LIST_HEAD(lookup->q);
         q != NULL;
         q = ISC_LIST_NEXT(q, link)) {
        if (q->working) {
            if (!free_now) {
                isc_buffer_clear(b);
                result = isc_sockaddr_totext(&q->sockaddr, b);
                check_result(result, "isc_sockaddr_totext");
                isc_buffer_usedregion(b, &r);
                printf(";; Connection to server %.*s for %s "
                       "failed: Connection timed out.\n",
                       (int)r.length, r.base,
                       q->lookup->textname);
            }
            isc_socket_cancel(q->sock, task,
                      ISC_SOCKCANCEL_ALL);
        }
    }
    ENSURE(lookup->timer != NULL);
    isc_timer_detach(&lookup->timer);
    isc_buffer_free(&b);
    isc_event_free(&event);
}

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

static void
tcp_length_done(isc_task_t *task, isc_event_t *event) {
    isc_socketevent_t *sevent;
    isc_buffer_t *b=NULL;
    isc_region_t r;
    isc_result_t result;
    dig_query_t *query=NULL;
    isc_uint16_t length;

    UNUSED(task);

#ifdef DEBUG
    fputs("In tcp_length_done\n", stderr);
#endif
    REQUIRE(event->ev_type == ISC_SOCKEVENT_RECVDONE);
    sevent = (isc_socketevent_t *)event;

    query = event->ev_arg;

    if (sevent->result == ISC_R_CANCELED) {
        query->working = ISC_FALSE;
        check_next_lookup(query->lookup);
        isc_event_free(&event);
        return;
    }
    if (sevent->result != ISC_R_SUCCESS) {
#ifdef DEBUG
        fputs ("Buffer Allocate connect_timeout\n",stderr);
#endif
        result = isc_buffer_allocate(mctx, &b, 256);
        check_result(result, "isc_buffer_allocate");
        result = isc_sockaddr_totext(&query->sockaddr, b);
        check_result(result, "isc_sockaddr_totext");
        isc_buffer_usedregion(b, &r);
        printf("%.*s: %s\n", (int)r.length, r.base,
               isc_result_totext(sevent->result));
        isc_buffer_free(&b);
        query->working = ISC_FALSE;
        isc_socket_detach(&query->sock);
        check_next_lookup(query->lookup);
        isc_event_free(&event);
        return;
    }
    b = ISC_LIST_HEAD(sevent->bufferlist);
    ISC_LIST_DEQUEUE(sevent->bufferlist, &query->lengthbuf, link);
    length = isc_buffer_getuint16(b);
    if (length > COMMSIZE)
        fatal ("Length was longer than I can handle!");
    /* XXXMWS Fix the above. */
    /*
     * 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_LIST_ENQUEUE(query->recvlist, &query->recvbuf, link);
    result = isc_socket_recvv(query->sock, &query->recvlist, length, task,
                  recv_done, query);
    check_result(result, "isc_socket_recvv");
#ifdef DEBUG
    fprintf(stderr, "Resubmitted recv request with length %d\n", length);
#endif
    isc_event_free(&event);
}

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

    if (!query->lookup->pending) {
#ifdef DEBUG
        fputs("Ignoring launch_next_query because !pending.\n",
              stderr);
#endif
        isc_socket_detach(&query->sock);
        query->working = ISC_FALSE;
        query->waiting_connect = ISC_FALSE;
        check_next_lookup(query->lookup);
        return;
    }

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

    result = isc_socket_recvv(query->sock, &query->lengthlist, 0, task,
                  tcp_length_done, query);
    check_result(result, "isc_socket_recvv");
    sendcount++;
#ifdef DEBUG
    fputs("Sending a request.\n", stderr);
#endif
    result = isc_socket_sendv(query->sock, &query->sendlist, task,
                  send_done, query);
    check_result(result, "isc_socket_recvv");
    query->waiting_connect = ISC_FALSE;
    check_next_lookup(query->lookup);
    return;
}

static void
connect_done(isc_task_t *task, isc_event_t *event) {
    isc_result_t result;
    isc_socketevent_t *sevent=NULL;
    dig_query_t *query=NULL;
    isc_buffer_t *b=NULL;
    isc_region_t r;

    UNUSED(task);

    REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
    sevent = (isc_socketevent_t *)event;
    query = sevent->ev_arg;

    REQUIRE(query->waiting_connect);

    query->waiting_connect = ISC_FALSE;

#ifdef DEBUG
    fputs("In connect_done.\n", stderr);
#endif
    if (sevent->result != ISC_R_SUCCESS) {
#ifdef DEBUG
        fputs ("Buffer Allocate connect_timeout\n",stderr);
#endif
        result = isc_buffer_allocate(mctx, &b, 256);
        check_result(result, "isc_buffer_allocate");
        result = isc_sockaddr_totext(&query->sockaddr, b);
        check_result(result, "isc_sockaddr_totext");
        isc_buffer_usedregion(b, &r);
        printf(";; Connection to server %.*s for %s failed: %s.\n",
               (int)r.length, r.base, query->lookup->textname,
               isc_result_totext(sevent->result));
        isc_buffer_free(&b);
        query->working = ISC_FALSE;
        query->waiting_connect = ISC_FALSE;
        check_next_lookup(query->lookup);
        isc_event_free(&event);
        return;
    }
    isc_event_free(&event);
    launch_next_query(query, ISC_TRUE);
}

static isc_boolean_t
msg_contains_soa(dns_message_t *msg, dig_query_t *query) {
    isc_result_t result;
    dns_name_t *name=NULL;

    result = dns_message_findname(msg, DNS_SECTION_ANSWER,
                      query->lookup->name, dns_rdatatype_soa,
                      0, &name, NULL);
    if (result == ISC_R_SUCCESS) {
#ifdef DEBUG
        fputs("Found SOA\n", stderr);
#endif
        return (ISC_TRUE);
    } else {
#ifdef DEBUG
        fprintf(stderr, "Didn't find SOA, result=%d:%s\n",
            result, dns_result_totext(result));
#endif
        return (ISC_FALSE);
    }

}

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;
    isc_buffer_t ab;
    char abspace[MXNAME];
    isc_region_t r;

    UNUSED (task);

    sendcount--;
#ifdef DEBUG
    fprintf(stderr, "In recv_done, counter down to %d\n", sendcount);
#endif
    REQUIRE(event->ev_type == ISC_SOCKEVENT_RECVDONE);
    sevent = (isc_socketevent_t *)event;
    query = event->ev_arg;

    if (!query->lookup->pending) {
#ifdef DEBUG
        fprintf(stderr, "No longer pending.  Got %s\n",
            isc_result_totext(sevent->result));
#endif
        query->working = ISC_FALSE;
        query->waiting_connect = ISC_FALSE;
        cancel_lookup(query->lookup);
        check_next_lookup(query->lookup);
        isc_event_free(&event);
        return;
    }

    if (sevent->result == ISC_R_SUCCESS) {
        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");
        result = dns_message_parse(msg, b, ISC_TRUE);
        if (result != ISC_R_SUCCESS)
            hex_dump(b);
        check_result(result, "dns_message_parse");
        if (query->lookup->xfr_q == NULL)
            query->lookup->xfr_q = query;
        if (query->lookup->xfr_q == query) {
            if (query->lookup->ns_search_only)
                followup_lookup(msg, query);
            else {
                if (query->first_soa_rcvd &&
                    query->lookup->doing_xfr)
                    printmessage(query, msg, ISC_FALSE);
                else
                    printmessage(query, msg, ISC_TRUE);
            }
        }
#ifdef DEBUG
        if (query->lookup->pending)
            fputs("Still pending.\n", stderr);
#endif
        if (query->lookup->doing_xfr) {
            if (!query->first_soa_rcvd) {
                if (!msg_contains_soa(msg, query)) {
                    puts("; Transfer failed.  "
                         "Didn't start with SOA answer.");
                    query->working = ISC_FALSE;
                    cancel_lookup(query->lookup);
                    check_next_lookup (query->lookup);
                    isc_event_free (&event);
                    dns_message_destroy (&msg);
                    return;
                }
                else {
                    query->first_soa_rcvd = ISC_TRUE;
                    launch_next_query(query, ISC_FALSE);
                }
            }
            else {
                if (msg_contains_soa(msg, query)) {
                    cancel_lookup(query->lookup);
                    query->working = ISC_FALSE;
                    check_next_lookup(query->lookup);
                    isc_event_free(&event);
                    dns_message_destroy (&msg);
                    return;
                }
                else {
                    launch_next_query(query, ISC_FALSE);
                }
            }
        }
        else {
            query->working = ISC_FALSE;
            cancel_lookup(query->lookup);
        }
        if (!query->lookup->pending) {
            isc_buffer_init(&ab, abspace, MXNAME);
            check_result(result, "isc_buffer_init");
            result = isc_sockaddr_totext(&sevent->address, &ab);
            check_result(result, "isc_sockaddr_totext");
            isc_buffer_usedregion(&ab, &r);
            if (!short_form)
                printf("; Received %u bytes from %s\n",
                       b->used, r.base);
            check_next_lookup(query->lookup);
        }
        dns_message_destroy(&msg);
        isc_event_free(&event);
        return;
    }
    /* In truth, we should never get into the CANCELED routine, since
       the cancel_lookup() routine clears the pending flag. */
    if (sevent->result == ISC_R_CANCELED) {
        query->working = ISC_FALSE;
        query->waiting_connect = ISC_FALSE;
        check_next_lookup(query->lookup);
        isc_event_free(&event);
        return;
    }
    fatal("recv_done got result %s",
          isc_result_totext(sevent->result));
}

static void
get_address(char *hostname, in_port_t port, isc_sockaddr_t *sockaddr) {
    struct in_addr in4;
    struct in6_addr in6;
    struct hostent *he;

    if (have_ipv6 && inet_pton(AF_INET6, hostname, &in6) == 1)
        isc_sockaddr_fromin6(sockaddr, &in6, port);
    else if (inet_pton(AF_INET, hostname, &in4) == 1)
        isc_sockaddr_fromin(sockaddr, &in4, port);
    else {
        he = gethostbyname(hostname);
        if (he == NULL)
             fatal("Couldn't look up your server host %s.  errno=%d",
                  hostname, h_errno);
        INSIST(he->h_addrtype == AF_INET);
        isc_sockaddr_fromin(sockaddr,
                    (struct in_addr *)(he->h_addr_list[0]),
                    port);
    }
}

void
do_lookup_tcp(dig_lookup_t *lookup) {
    dig_query_t *query;
    isc_result_t result;

#ifdef DEBUG
    fputs("Starting a TCP lookup\n", stderr);
#endif
    lookup->pending = ISC_TRUE;
    isc_interval_set(&lookup->interval, timeout, 0);
    result = isc_timer_create(timermgr, isc_timertype_once, NULL,
                  &lookup->interval, task, connect_timeout,
                  lookup, &lookup->timer);
    check_result(result, "isc_timer_create");

    for (query = ISC_LIST_HEAD(lookup->q);
         query != NULL;
         query = ISC_LIST_NEXT(query, link)) {
        query->working = ISC_TRUE;
        query->waiting_connect = ISC_TRUE;
        get_address(query->servname, port, &query->sockaddr);

        result = isc_socket_create(socketmgr,
                       isc_sockaddr_pf(&query->sockaddr),
                       isc_sockettype_tcp, &query->sock) ;
        check_result(result, "isc_socket_create");
        result = isc_socket_connect(query->sock, &query->sockaddr,
                        task, connect_done, query);
        check_result (result, "isc_socket_connect");
    }
}

void
do_lookup_udp(dig_lookup_t *lookup) {
    dig_query_t *query;
    isc_result_t result;

#ifdef DEBUG
    fputs("Starting a UDP lookup.\n", stderr);
    if (tcp_mode)
        fputs ("I'm starting UDP with tcp_mode set!!!\n",stderr);
#endif
    lookup->pending = ISC_TRUE;
    isc_interval_set(&lookup->interval, timeout, 0);
    result = isc_timer_create(timermgr, isc_timertype_once, NULL,
                  &lookup->interval, task, connect_timeout,
                  lookup, &lookup->timer);
    check_result(result, "isc_timer_create");

    for (query = ISC_LIST_HEAD(lookup->q);
         query != NULL;
         query = ISC_LIST_NEXT(query, link)) {
        query->working = ISC_TRUE;
        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");
        ISC_LIST_ENQUEUE(query->recvlist, &query->recvbuf, link);
        result = isc_socket_recvv(query->sock, &query->recvlist, 1,
                      task, recv_done, query);
        check_result(result, "isc_socket_recvv");
        sendcount++;
#ifdef DEBUG
        fprintf(stderr, "Sent count number %d\n", sendcount);
#endif
        ISC_LIST_ENQUEUE(query->sendlist, &lookup->sendbuf, link);
        result = isc_socket_sendtov(query->sock, &query->sendlist,
                        task, send_done, query,
                        &query->sockaddr, NULL);
        check_result(result, "isc_socket_sendtov");
    }
}

static void
free_lists(void) {
    void *ptr;
    dig_lookup_t *l;
    dig_query_t *q;
    dig_server_t *s;

    l = ISC_LIST_HEAD(lookup_list);
    while (l != NULL) {
        q = ISC_LIST_HEAD(l->q);
        while (q != NULL) {
            if (q->sock != NULL) {
                isc_socket_cancel(q->sock, NULL,
                          ISC_SOCKCANCEL_ALL);
                isc_socket_detach(&q->sock);
            }
            if (ISC_LINK_LINKED(&q->recvbuf, link))
                ISC_LIST_DEQUEUE(q->recvlist, &q->recvbuf,
                         link);
            if (ISC_LINK_LINKED(&q->lengthbuf, link))
                ISC_LIST_DEQUEUE(q->lengthlist, &q->lengthbuf,
                         link);
            isc_buffer_invalidate(&q->recvbuf);
            isc_buffer_invalidate(&q->lengthbuf);
            ptr = q;
            q = ISC_LIST_NEXT(q, link);
            isc_mem_free(mctx, ptr);
        }
        if (l->use_my_server_list) {
            s = ISC_LIST_HEAD(l->my_server_list);
            while (s != NULL) {
                ptr = s;
                s = ISC_LIST_NEXT(s, link);
                isc_mem_free(mctx, ptr);

            }
        }
        if (l->sendmsg != NULL)
            dns_message_destroy (&l->sendmsg);
        if (l->timer != NULL)
            isc_timer_detach (&l->timer);
        ptr = l;
        l = ISC_LIST_NEXT(l, link);
        isc_mem_free(mctx, ptr);
    }
    s = ISC_LIST_HEAD(server_list);
    while (s != NULL) {
        ptr = s;
        s = ISC_LIST_NEXT(s, link);
        isc_mem_free(mctx, ptr);
    }
    dns_name_invalidate(&rootorg);
    if (socketmgr != NULL)
        isc_socketmgr_destroy(&socketmgr);
    if (timermgr != NULL)
        isc_timermgr_destroy(&timermgr);
    if (task != NULL)
        isc_task_detach(&task);
    if (taskmgr != NULL)
        isc_taskmgr_destroy(&taskmgr);
}

int
main(int argc, char **argv) {
    dig_lookup_t *lookup = NULL;

    ISC_LIST_INIT(lookup_list);
    ISC_LIST_INIT(server_list);

    setup_libs();
    port = 53;
    timeout = 10;
    parse_args(ISC_FALSE, argc, argv);
    setup_system();
    lookup = ISC_LIST_HEAD(lookup_list);
    setup_lookup(lookup);
    if (tcp_mode)
        do_lookup_tcp(lookup);
    else
        do_lookup_udp(lookup);
    isc_app_run();
    free_now = ISC_TRUE;
    free_lists();
#ifdef MEMDEBUG
    isc_mem_stats(mctx, stderr);
#endif
    isc_app_finish();
    if (mctx != NULL)
        isc_mem_destroy(&mctx);

    return (0);
}