resolv/res_debug.cpp

/*	$NetBSD: res_debug.c,v 1.13 2012/06/25 22:32:45 abs Exp $	*/

/*
 * Portions Copyright (C) 2004, 2005, 2008, 2009  Internet Systems Consortium, Inc. ("ISC")
 * Portions Copyright (C) 1996-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Copyright (c) 1985
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 *
 * 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, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION 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.
 */

/*
 * Portions Copyright (c) 1995 by International Business Machines, Inc.
 *
 * International Business Machines, Inc. (hereinafter called IBM) grants
 * permission under its copyrights to use, copy, modify, and distribute this
 * Software with or without fee, provided that the above copyright notice and
 * all paragraphs of this notice appear in all copies, and that the name of IBM
 * not be used in connection with the marketing of any product incorporating
 * the Software or modifications thereof, without specific, written prior
 * permission.
 *
 * To the extent it has a right to do so, IBM grants an immunity from suit
 * under its patents, if any, for the use, sale or manufacture of products to
 * the extent that such products are used for performing Domain Name System
 * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
 * granted for any product per se or for any other function of any product.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netinet/in.h>

#include <ctype.h>
#include <errno.h>
#include <math.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <time.h>
#include "resolv_private.h"


extern const char* const _res_opcodes[];

static void do_section(const res_state statp, ns_msg* handle, ns_sect section, int pflag,
                       FILE* file) {
    int n, sflag, rrnum;
    int buflen = 2048;
    ns_opcode opcode;
    ns_rr rr;

    /*
     * Print answer records.
     */
    sflag = (int) (statp->pfcode & pflag);
    if (statp->pfcode && !sflag) return;

    char* buf = (char*) malloc((size_t) buflen);
    if (buf == NULL) {
        fprintf(file, ";; memory allocation failure\n");
        return;
    }

    opcode = (ns_opcode) ns_msg_getflag(*handle, ns_f_opcode);
    rrnum = 0;
    for (;;) {
        if (ns_parserr(handle, section, rrnum, &rr)) {
            if (errno != ENODEV)
                fprintf(file, ";; ns_parserr: %s\n", strerror(errno));
            else if (rrnum > 0 && sflag != 0 && (statp->pfcode & RES_PRF_HEAD1))
                putc('\n', file);
            goto cleanup;
        }
        if (rrnum == 0 && sflag != 0 && (statp->pfcode & RES_PRF_HEAD1))
            fprintf(file, ";; %s SECTION:\n", p_section(section, opcode));
        if (section == ns_s_qd)
            fprintf(file, ";;\t%s, type = %s, class = %s\n", ns_rr_name(rr), p_type(ns_rr_type(rr)),
                    p_class(ns_rr_class(rr)));
        else if (section == ns_s_ar && ns_rr_type(rr) == ns_t_opt) {
            size_t rdatalen, ttl;
            uint16_t optcode, optlen;

            rdatalen = ns_rr_rdlen(rr);
            ttl = ns_rr_ttl(rr);
            fprintf(file, "; EDNS: version: %zu, udp=%u, flags=%04zx\n", (ttl >> 16) & 0xff,
                    ns_rr_class(rr), ttl & 0xffff);
            while (rdatalen >= 4) {
                const u_char* cp = ns_rr_rdata(rr);
                int i;

                GETSHORT(optcode, cp);
                GETSHORT(optlen, cp);

                if (optcode == NS_OPT_NSID) {
                    fputs("; NSID: ", file);
                    if (optlen == 0) {
                        fputs("; NSID\n", file);
                    } else {
                        fputs("; NSID: ", file);
                        for (i = 0; i < optlen; i++) fprintf(file, "%02x ", cp[i]);
                        fputs(" (", file);
                        for (i = 0; i < optlen; i++)
                            fprintf(file, "%c", isprint(cp[i]) ? cp[i] : '.');
                        fputs(")\n", file);
                    }
                } else {
                    if (optlen == 0) {
                        fprintf(file, "; OPT=%u\n", optcode);
                    } else {
                        fprintf(file, "; OPT=%u: ", optcode);
                        for (i = 0; i < optlen; i++) fprintf(file, "%02x ", cp[i]);
                        fputs(" (", file);
                        for (i = 0; i < optlen; i++)
                            fprintf(file, "%c", isprint(cp[i]) ? cp[i] : '.');
                        fputs(")\n", file);
                    }
                }
                rdatalen -= 4 + optlen;
            }
        } else {
            n = ns_sprintrr(handle, &rr, NULL, NULL, buf, (u_int) buflen);
            if (n < 0) {
                if (errno == ENOSPC) {
                    free(buf);
                    buf = NULL;
                    if (buflen < 131072) {
                        buf = (char*) malloc((size_t)(buflen += 1024));
                    }
                    if (buf == NULL) {
                        fprintf(file, ";; memory allocation failure\n");
                        return;
                    }
                    continue;
                }
                fprintf(file, ";; ns_sprintrr: %s\n", strerror(errno));
                goto cleanup;
            }
            fputs(buf, file);
            fputc('\n', file);
        }
        rrnum++;
    }
cleanup:
    free(buf);
}

/*
 * Print the contents of a query.
 * This is intended to be primarily a debugging routine.
 */
void res_pquery(const res_state statp, const u_char* msg, int len, FILE* file) {
    ns_msg handle;
    int qdcount, ancount, nscount, arcount;
    u_int opcode, rcode, id;

    if (ns_initparse(msg, len, &handle) < 0) {
        fprintf(file, ";; ns_initparse: %s\n", strerror(errno));
        return;
    }
    opcode = ns_msg_getflag(handle, ns_f_opcode);
    rcode = ns_msg_getflag(handle, ns_f_rcode);
    id = ns_msg_id(handle);
    qdcount = ns_msg_count(handle, ns_s_qd);
    ancount = ns_msg_count(handle, ns_s_an);
    nscount = ns_msg_count(handle, ns_s_ns);
    arcount = ns_msg_count(handle, ns_s_ar);

    /*
     * Print header fields.
     */
    if ((!statp->pfcode) || (statp->pfcode & RES_PRF_HEADX) || rcode)
        fprintf(file, ";; ->>HEADER<<- opcode: %s, status: %s, id: %d\n", _res_opcodes[opcode],
                p_rcode((int) rcode), id);
    if ((!statp->pfcode) || (statp->pfcode & RES_PRF_HEADX)) putc(';', file);
    if ((!statp->pfcode) || (statp->pfcode & RES_PRF_HEAD2)) {
        fprintf(file, "; flags:");
        if (ns_msg_getflag(handle, ns_f_qr)) fprintf(file, " qr");
        if (ns_msg_getflag(handle, ns_f_aa)) fprintf(file, " aa");
        if (ns_msg_getflag(handle, ns_f_tc)) fprintf(file, " tc");
        if (ns_msg_getflag(handle, ns_f_rd)) fprintf(file, " rd");
        if (ns_msg_getflag(handle, ns_f_ra)) fprintf(file, " ra");
        if (ns_msg_getflag(handle, ns_f_z)) fprintf(file, " ??");
        if (ns_msg_getflag(handle, ns_f_ad)) fprintf(file, " ad");
        if (ns_msg_getflag(handle, ns_f_cd)) fprintf(file, " cd");
    }
    if ((!statp->pfcode) || (statp->pfcode & RES_PRF_HEAD1)) {
        fprintf(file, "; %s: %d", p_section(ns_s_qd, (int) opcode), qdcount);
        fprintf(file, ", %s: %d", p_section(ns_s_an, (int) opcode), ancount);
        fprintf(file, ", %s: %d", p_section(ns_s_ns, (int) opcode), nscount);
        fprintf(file, ", %s: %d", p_section(ns_s_ar, (int) opcode), arcount);
    }
    if ((!statp->pfcode) || (statp->pfcode & (RES_PRF_HEADX | RES_PRF_HEAD2 | RES_PRF_HEAD1))) {
        putc('\n', file);
    }
    /*
     * Print the various sections.
     */
    do_section(statp, &handle, ns_s_qd, RES_PRF_QUES, file);
    do_section(statp, &handle, ns_s_an, RES_PRF_ANS, file);
    do_section(statp, &handle, ns_s_ns, RES_PRF_AUTH, file);
    do_section(statp, &handle, ns_s_ar, RES_PRF_ADD, file);
    if (qdcount == 0 && ancount == 0 && nscount == 0 && arcount == 0) putc('\n', file);
}

const u_char* p_cdnname(const u_char* cp, const u_char* msg, int len, FILE* file) {
    char name[MAXDNAME];
    int n;

    if ((n = dn_expand(msg, msg + len, cp, name, (int) sizeof name)) < 0) return (NULL);
    if (name[0] == '\0')
        putc('.', file);
    else
        fputs(name, file);
    return (cp + n);
}

const u_char* p_cdname(const u_char* cp, const u_char* msg, FILE* file) {
    return (p_cdnname(cp, msg, PACKETSZ, file));
}

/* Return a fully-qualified domain name from a compressed name (with
   length supplied).  */

const u_char* p_fqnname(const u_char* cp, const u_char* msg, int msglen, char* name, int namelen) {
    int n;
    size_t newlen;

    if ((n = dn_expand(msg, cp + msglen, cp, name, namelen)) < 0) return (NULL);
    newlen = strlen(name);
    if (newlen == 0 || name[newlen - 1] != '.') {
        if ((int) newlen + 1 >= namelen) /* Lack space for final dot */
            return (NULL);
        else
            strcpy(name + newlen, ".");
    }
    return (cp + n);
}

/* XXX:	the rest of these functions need to become length-limited, too. */

const u_char* p_fqname(const u_char* cp, const u_char* msg, FILE* file) {
    char name[MAXDNAME];
    const u_char* n;

    n = p_fqnname(cp, msg, MAXCDNAME, name, (int) sizeof name);
    if (n == NULL) return (NULL);
    fputs(name, file);
    return (n);
}

/*
 * Names of RR classes and qclasses.  Classes and qclasses are the same, except
 * that C_ANY is a qclass but not a class.  (You can ask for records of class
 * C_ANY, but you can't have any records of that class in the database.)
 */
const struct res_sym __p_class_syms[] = {
        {C_IN, "IN", (char*) 0},     {C_CHAOS, "CH", (char*) 0},  {C_CHAOS, "CHAOS", (char*) 0},
        {C_HS, "HS", (char*) 0},     {C_HS, "HESIOD", (char*) 0}, {C_ANY, "ANY", (char*) 0},
        {C_NONE, "NONE", (char*) 0}, {C_IN, (char*) 0, (char*) 0}};

/*
 * Names of message sections.
 */
static const struct res_sym __p_default_section_syms[] = {{ns_s_qd, "QUERY", (char*) 0},
                                                          {ns_s_an, "ANSWER", (char*) 0},
                                                          {ns_s_ns, "AUTHORITY", (char*) 0},
                                                          {ns_s_ar, "ADDITIONAL", (char*) 0},
                                                          {0, (char*) 0, (char*) 0}};

static const struct res_sym __p_update_section_syms[] = {{S_ZONE, "ZONE", (char*) 0},
                                                         {S_PREREQ, "PREREQUISITE", (char*) 0},
                                                         {S_UPDATE, "UPDATE", (char*) 0},
                                                         {S_ADDT, "ADDITIONAL", (char*) 0},
                                                         {0, (char*) 0, (char*) 0}};

/*
 * Names of RR types and qtypes.  Types and qtypes are the same, except
 * that T_ANY is a qtype but not a type.  (You can ask for records of type
 * T_ANY, but you can't have any records of that type in the database.)
 */
const struct res_sym __p_type_syms[] = {
        {ns_t_a, "A", "address"},
        {ns_t_ns, "NS", "name server"},
        {ns_t_md, "MD", "mail destination (deprecated)"},
        {ns_t_mf, "MF", "mail forwarder (deprecated)"},
        {ns_t_cname, "CNAME", "canonical name"},
        {ns_t_soa, "SOA", "start of authority"},
        {ns_t_mb, "MB", "mailbox"},
        {ns_t_mg, "MG", "mail group member"},
        {ns_t_mr, "MR", "mail rename"},
        {ns_t_null, "NULL", "null"},
        {ns_t_wks, "WKS", "well-known service (deprecated)"},
        {ns_t_ptr, "PTR", "domain name pointer"},
        {ns_t_hinfo, "HINFO", "host information"},
        {ns_t_minfo, "MINFO", "mailbox information"},
        {ns_t_mx, "MX", "mail exchanger"},
        {ns_t_txt, "TXT", "text"},
        {ns_t_rp, "RP", "responsible person"},
        {ns_t_afsdb, "AFSDB", "DCE or AFS server"},
        {ns_t_x25, "X25", "X25 address"},
        {ns_t_isdn, "ISDN", "ISDN address"},
        {ns_t_rt, "RT", "router"},
        {ns_t_nsap, "NSAP", "nsap address"},
        {ns_t_nsap_ptr, "NSAP_PTR", "domain name pointer"},
        {ns_t_sig, "SIG", "signature"},
        {ns_t_key, "KEY", "key"},
        {ns_t_px, "PX", "mapping information"},
        {ns_t_gpos, "GPOS", "geographical position (withdrawn)"},
        {ns_t_aaaa, "AAAA", "IPv6 address"},
        {ns_t_loc, "LOC", "location"},
        {ns_t_nxt, "NXT", "next valid name (unimplemented)"},
        {ns_t_eid, "EID", "endpoint identifier (unimplemented)"},
        {ns_t_nimloc, "NIMLOC", "NIMROD locator (unimplemented)"},
        {ns_t_srv, "SRV", "server selection"},
        {ns_t_atma, "ATMA", "ATM address (unimplemented)"},
        {ns_t_naptr, "NAPTR", "naptr"},
        {ns_t_kx, "KX", "key exchange"},
        {ns_t_cert, "CERT", "certificate"},
        {ns_t_a6, "A", "IPv6 address (experminental)"},
        {ns_t_dname, "DNAME", "non-terminal redirection"},
        {ns_t_opt, "OPT", "opt"},
        {ns_t_apl, "apl", "apl"},
        {ns_t_ds, "DS", "delegation signer"},
        {ns_t_sshfp, "SSFP", "SSH fingerprint"},
        {ns_t_ipseckey, "IPSECKEY", "IPSEC key"},
        {ns_t_rrsig, "RRSIG", "rrsig"},
        {ns_t_nsec, "NSEC", "nsec"},
        {ns_t_dnskey, "DNSKEY", "DNS key"},
        {ns_t_dhcid, "DHCID", "dynamic host configuration identifier"},
        {ns_t_nsec3, "NSEC3", "nsec3"},
        {ns_t_nsec3param, "NSEC3PARAM", "NSEC3 parameters"},
        {ns_t_hip, "HIP", "host identity protocol"},
        {ns_t_spf, "SPF", "sender policy framework"},
        {ns_t_tkey, "TKEY", "tkey"},
        {ns_t_tsig, "TSIG", "transaction signature"},
        {ns_t_ixfr, "IXFR", "incremental zone transfer"},
        {ns_t_axfr, "AXFR", "zone transfer"},
        {ns_t_zxfr, "ZXFR", "compressed zone transfer"},
        {ns_t_mailb, "MAILB", "mailbox-related data (deprecated)"},
        {ns_t_maila, "MAILA", "mail agent (deprecated)"},
        {ns_t_naptr, "NAPTR", "URN Naming Authority"},
        {ns_t_kx, "KX", "Key Exchange"},
        {ns_t_cert, "CERT", "Certificate"},
        {ns_t_a6, "A6", "IPv6 Address"},
        {ns_t_dname, "DNAME", "dname"},
        {ns_t_sink, "SINK", "Kitchen Sink (experimental)"},
        {ns_t_opt, "OPT", "EDNS Options"},
        {ns_t_any, "ANY", "\"any\""},
        {ns_t_dlv, "DLV", "DNSSEC look-aside validation"},
        {0, NULL, NULL}};

/*
 * Names of DNS rcodes.
 */
const struct res_sym __p_rcode_syms[] = {{ns_r_noerror, "NOERROR", "no error"},
                                         {ns_r_formerr, "FORMERR", "format error"},
                                         {ns_r_servfail, "SERVFAIL", "server failed"},
                                         {ns_r_nxdomain, "NXDOMAIN", "no such domain name"},
                                         {ns_r_notimpl, "NOTIMP", "not implemented"},
                                         {ns_r_refused, "REFUSED", "refused"},
                                         {ns_r_yxdomain, "YXDOMAIN", "domain name exists"},
                                         {ns_r_yxrrset, "YXRRSET", "rrset exists"},
                                         {ns_r_nxrrset, "NXRRSET", "rrset doesn't exist"},
                                         {ns_r_notauth, "NOTAUTH", "not authoritative"},
                                         {ns_r_notzone, "NOTZONE", "Not in zone"},
                                         {ns_r_max, "", ""},
                                         {ns_r_badsig, "BADSIG", "bad signature"},
                                         {ns_r_badkey, "BADKEY", "bad key"},
                                         {ns_r_badtime, "BADTIME", "bad time"},
                                         {0, NULL, NULL}};

static const char* sym_ntos(const struct res_sym* syms, int number, int* success) {
    static char unname[20];

    for (; syms->name != 0; syms++) {
        if (number == syms->number) {
            if (success) *success = 1;
            return (syms->name);
        }
    }

    snprintf(unname, sizeof(unname), "%d", number); /* XXX nonreentrant */
    if (success) *success = 0;
    return (unname);
}

/*
 * Return a string for the type.
 */
const char* p_type(int type) {
    int success;
    const char* result;
    static char typebuf[20];

    result = sym_ntos(__p_type_syms, type, &success);
    if (success) return (result);
    if (type < 0 || type > 0xffff) return ("BADTYPE");
    snprintf(typebuf, sizeof(typebuf), "TYPE%d", type);
    return (typebuf);
}

/*
 * Return a string for the type.
 */
const char* p_section(int section, int opcode) {
    const struct res_sym* symbols;

    switch (opcode) {
        case ns_o_update:
            symbols = __p_update_section_syms;
            break;
        default:
            symbols = __p_default_section_syms;
            break;
    }
    return (sym_ntos(symbols, section, (int*) 0));
}

/*
 * Return a mnemonic for class.
 */
const char* p_class(int cl) {
    int success;
    const char* result;
    static char classbuf[20];

    result = sym_ntos(__p_class_syms, cl, &success);
    if (success) return (result);
    if (cl < 0 || cl > 0xffff) return ("BADCLASS");
    snprintf(classbuf, sizeof(classbuf), "CLASS%d", cl);
    return (classbuf);
}

/*
 * Return a mnemonic for an option
 */
const char* p_option(u_long option) {
    static char nbuf[40];

    switch (option) {
        case RES_INIT:
            return "init";
        case RES_DEBUG:
            return "debug";
        case RES_AAONLY:
            return "aaonly(unimpl)";
        case RES_USEVC:
            return "usevc";
        case RES_PRIMARY:
            return "primry(unimpl)";
        case RES_IGNTC:
            return "igntc";
        case RES_RECURSE:
            return "recurs";
        case RES_DEFNAMES:
            return "defnam";
        case RES_STAYOPEN:
            return "styopn";
        case RES_DNSRCH:
            return "dnsrch";
        case RES_INSECURE1:
            return "insecure1";
        case RES_INSECURE2:
            return "insecure2";
        case RES_NOALIASES:
            return "noaliases";
        case RES_USE_INET6:
            return "inet6";
#ifdef RES_USE_EDNS0 /* KAME extension */
        case RES_USE_EDNS0:
            return "edns0";
#endif
#ifdef RES_USE_DNAME
        case RES_USE_DNAME:
            return "dname";
#endif
#ifdef RES_USE_DNSSEC
        case RES_USE_DNSSEC:
            return "dnssec";
#endif
#ifdef RES_NOTLDQUERY
        case RES_NOTLDQUERY:
            return "no-tld-query";
#endif
#ifdef RES_NO_NIBBLE2
        case RES_NO_NIBBLE2:
            return "no-nibble2";
#endif
            /* XXX nonreentrant */
        default:
            snprintf(nbuf, sizeof(nbuf), "?0x%lx?", (u_long) option);
            return (nbuf);
    }
}

/*
 * Return a mnemonic for a time to live.
 */
const char* p_time(u_int32_t value) {
    static char nbuf[40]; /* XXX nonreentrant */

    if (ns_format_ttl((u_long) value, nbuf, sizeof nbuf) < 0)
        snprintf(nbuf, sizeof(nbuf), "%u", value);
    return (nbuf);
}

/*
 * Return a string for the rcode.
 */
const char* p_rcode(int rcode) {
    return (sym_ntos(__p_rcode_syms, rcode, (int*) 0));
}

/*
 * Return a string for a res_sockaddr_union.
 */
const char* p_sockun(union res_sockaddr_union u, char* buf, size_t size) {
    char ret[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:123.123.123.123"];

    switch (u.sin.sin_family) {
        case AF_INET:
            inet_ntop(AF_INET, &u.sin.sin_addr, ret, (socklen_t) sizeof ret);
            break;
        case AF_INET6:
            inet_ntop(AF_INET6, &u.sin6.sin6_addr, ret, sizeof ret);
            break;
        default:
            snprintf(ret, sizeof(ret), "[af%d]", u.sin.sin_family);
            break;
    }
    if (size > 0U) {
        strncpy(buf, ret, size - 1);
        buf[size - 1] = '0';
    }
    return (buf);
}

/*
 * routines to convert between on-the-wire RR format and zone file format.
 * Does not contain conversion to/from decimal degrees; divide or multiply
 * by 60*60*1000 for that.
 */

static const unsigned int poweroften[10] = {1,      10,      100,      1000,      10000,
                                            100000, 1000000, 10000000, 100000000, 1000000000};

/* takes an XeY precision/size value, returns a string representation. */
static const char* precsize_ntoa(u_int32_t prec) {
    static char retbuf[sizeof "90000000.00"]; /* XXX nonreentrant */
    unsigned long val;
    int mantissa, exponent;

    mantissa = (int) ((prec >> 4) & 0x0f) % 10;
    exponent = (int) ((prec >> 0) & 0x0f) % 10;

    val = mantissa * poweroften[exponent];

    (void) snprintf(retbuf, sizeof(retbuf), "%lu.%.2lu", val / 100, val % 100);
    return (retbuf);
}

/* converts ascii size/precision X * 10**Y(cm) to 0xXY.  moves pointer. */
static u_int8_t precsize_aton(const char** strptr) {
    unsigned int mval = 0, cmval = 0;
    u_int8_t retval = 0;
    const char* cp;
    int exponent;
    int mantissa;

    cp = *strptr;

    while (isdigit((unsigned char) *cp)) mval = mval * 10 + (*cp++ - '0');

    if (*cp == '.') { /* centimeters */
        cp++;
        if (isdigit((unsigned char) *cp)) {
            cmval = (*cp++ - '0') * 10;
            if (isdigit((unsigned char) *cp)) {
                cmval += (*cp++ - '0');
            }
        }
    }
    cmval = (mval * 100) + cmval;

    for (exponent = 0; exponent < 9; exponent++)
        if (cmval < poweroften[exponent + 1]) break;

    mantissa = cmval / poweroften[exponent];
    if (mantissa > 9) mantissa = 9;

    retval = (mantissa << 4) | exponent;

    *strptr = cp;

    return (retval);
}

/* converts ascii lat/lon to unsigned encoded 32-bit number.  moves pointer. */
static u_int32_t latlon2ul(const char** latlonstrptr, int* which) {
    const char* cp;
    u_int32_t retval;
    int deg = 0, min = 0, secs = 0, secsfrac = 0;

    cp = *latlonstrptr;

    while (isdigit((unsigned char) *cp)) deg = deg * 10 + (*cp++ - '0');

    while (isspace((unsigned char) *cp)) cp++;

    if (!(isdigit((unsigned char) *cp))) goto fndhemi;

    while (isdigit((unsigned char) *cp)) min = min * 10 + (*cp++ - '0');

    while (isspace((unsigned char) *cp)) cp++;

    if (!(isdigit((unsigned char) *cp))) goto fndhemi;

    while (isdigit((unsigned char) *cp)) secs = secs * 10 + (*cp++ - '0');

    if (*cp == '.') { /* decimal seconds */
        cp++;
        if (isdigit((unsigned char) *cp)) {
            secsfrac = (*cp++ - '0') * 100;
            if (isdigit((unsigned char) *cp)) {
                secsfrac += (*cp++ - '0') * 10;
                if (isdigit((unsigned char) *cp)) {
                    secsfrac += (*cp++ - '0');
                }
            }
        }
    }

    while (!isspace((unsigned char) *cp)) /* if any trailing garbage */
        cp++;

    while (isspace((unsigned char) *cp)) cp++;

fndhemi:
    switch (*cp) {
        case 'N':
        case 'n':
        case 'E':
        case 'e':
            retval = ((unsigned) 1 << 31) + (((((deg * 60) + min) * 60) + secs) * 1000) + secsfrac;
            break;
        case 'S':
        case 's':
        case 'W':
        case 'w':
            retval = ((unsigned) 1 << 31) - (((((deg * 60) + min) * 60) + secs) * 1000) - secsfrac;
            break;
        default:
            retval = 0; /* invalid value -- indicates error */
            break;
    }

    switch (*cp) {
        case 'N':
        case 'n':
        case 'S':
        case 's':
            *which = 1; /* latitude */
            break;
        case 'E':
        case 'e':
        case 'W':
        case 'w':
            *which = 2; /* longitude */
            break;
        default:
            *which = 0; /* error */
            break;
    }

    cp++; /* skip the hemisphere */

    while (!isspace((unsigned char) *cp)) /* if any trailing garbage */
        cp++;

    while (isspace((unsigned char) *cp)) /* move to next field */
        cp++;

    *latlonstrptr = cp;

    return (retval);
}

/* converts a zone file representation in a string to an RDATA on-the-wire
 * representation. */
int loc_aton(const char* ascii, u_char* binary) {
    const char *cp, *maxcp;
    u_char* bcp;

    u_int32_t latit = 0, longit = 0, alt = 0;
    u_int32_t lltemp1 = 0, lltemp2 = 0;
    int altmeters = 0, altfrac = 0, altsign = 1;
    u_int8_t hp = 0x16;  /* default = 1e6 cm = 10000.00m = 10km */
    u_int8_t vp = 0x13;  /* default = 1e3 cm = 10.00m */
    u_int8_t siz = 0x12; /* default = 1e2 cm = 1.00m */
    int which1 = 0, which2 = 0;

    cp = ascii;
    maxcp = cp + strlen(ascii);

    lltemp1 = latlon2ul(&cp, &which1);

    lltemp2 = latlon2ul(&cp, &which2);

    switch (which1 + which2) {
        case 3:                                   /* 1 + 2, the only valid combination */
            if ((which1 == 1) && (which2 == 2)) { /* normal case */
                latit = lltemp1;
                longit = lltemp2;
            } else if ((which1 == 2) && (which2 == 1)) { /* reversed */
                longit = lltemp1;
                latit = lltemp2;
            } else { /* some kind of brokenness */
                return (0);
            }
            break;
        default: /* we didn't get one of each */
            return (0);
    }

    /* altitude */
    if (*cp == '-') {
        altsign = -1;
        cp++;
    }

    if (*cp == '+') cp++;

    while (isdigit((unsigned char) *cp)) altmeters = altmeters * 10 + (*cp++ - '0');

    if (*cp == '.') { /* decimal meters */
        cp++;
        if (isdigit((unsigned char) *cp)) {
            altfrac = (*cp++ - '0') * 10;
            if (isdigit((unsigned char) *cp)) {
                altfrac += (*cp++ - '0');
            }
        }
    }

    alt = (10000000 + (altsign * (altmeters * 100 + altfrac)));

    while (!isspace((unsigned char) *cp) && (cp < maxcp)) /* if trailing garbage or m */
        cp++;

    while (isspace((unsigned char) *cp) && (cp < maxcp)) cp++;

    if (cp >= maxcp) goto defaults;

    siz = precsize_aton(&cp);

    while (!isspace((unsigned char) *cp) && (cp < maxcp)) /* if trailing garbage or m */
        cp++;

    while (isspace((unsigned char) *cp) && (cp < maxcp)) cp++;

    if (cp >= maxcp) goto defaults;

    hp = precsize_aton(&cp);

    while (!isspace((unsigned char) *cp) && (cp < maxcp)) /* if trailing garbage or m */
        cp++;

    while (isspace((unsigned char) *cp) && (cp < maxcp)) cp++;

    if (cp >= maxcp) goto defaults;

    vp = precsize_aton(&cp);

defaults:

    bcp = binary;
    *bcp++ = (u_int8_t) 0; /* version byte */
    *bcp++ = siz;
    *bcp++ = hp;
    *bcp++ = vp;
    PUTLONG(latit, bcp);
    PUTLONG(longit, bcp);
    PUTLONG(alt, bcp);

    return (16); /* size of RR in octets */
}

/* takes an on-the-wire LOC RR and formats it in a human readable format. */
const char* loc_ntoa(const u_char* binary, char* ascii, size_t bufsiz) {
    static const char* error = "?";
    static char tmpbuf[sizeof
"1000 60 60.000 N 1000 60 60.000 W -12345678.00m 90000000.00m 90000000.00m 90000000.00m"];
    const u_char* cp = binary;

    int latdeg, latmin, latsec, latsecfrac;
    int longdeg, longmin, longsec, longsecfrac;
    char northsouth, eastwest;
    const char* altsign;
    int altmeters, altfrac;

    const u_int32_t referencealt = 100000 * 100;

    int32_t latval, longval, altval;
    u_int32_t templ;
    u_int8_t sizeval, hpval, vpval, versionval;

    char *sizestr, *hpstr, *vpstr;

    versionval = *cp++;

    if (ascii == NULL) ascii = tmpbuf;

    if (versionval) {
        (void) snprintf(ascii, bufsiz, "; error: unknown LOC RR version");
        return (ascii);
    }

    sizeval = *cp++;

    hpval = *cp++;
    vpval = *cp++;

    GETLONG(templ, cp);
    latval = (templ - ((unsigned) 1 << 31));

    GETLONG(templ, cp);
    longval = (templ - ((unsigned) 1 << 31));

    GETLONG(templ, cp);
    if (templ < referencealt) { /* below WGS 84 spheroid */
        altval = referencealt - templ;
        altsign = "-";
    } else {
        altval = templ - referencealt;
        altsign = "";
    }

    if (latval < 0) {
        northsouth = 'S';
        latval = -latval;
    } else
        northsouth = 'N';

    latsecfrac = latval % 1000;
    latval = latval / 1000;
    latsec = latval % 60;
    latval = latval / 60;
    latmin = latval % 60;
    latval = latval / 60;
    latdeg = latval;

    if (longval < 0) {
        eastwest = 'W';
        longval = -longval;
    } else
        eastwest = 'E';

    longsecfrac = longval % 1000;
    longval = longval / 1000;
    longsec = longval % 60;
    longval = longval / 60;
    longmin = longval % 60;
    longval = longval / 60;
    longdeg = longval;

    altfrac = altval % 100;
    altmeters = (altval / 100);

    sizestr = strdup(precsize_ntoa((u_int32_t) sizeval));
    hpstr = strdup(precsize_ntoa((u_int32_t) hpval));
    vpstr = strdup(precsize_ntoa((u_int32_t) vpval));

    snprintf(ascii, bufsiz, "%d %.2d %.2d.%.3d %c %d %.2d %.2d.%.3d %c %s%d.%.2dm %sm %sm %sm",
             latdeg, latmin, latsec, latsecfrac, northsouth, longdeg, longmin, longsec, longsecfrac,
             eastwest, altsign, altmeters, altfrac, (sizestr != NULL) ? sizestr : error,
             (hpstr != NULL) ? hpstr : error, (vpstr != NULL) ? vpstr : error);

    free(sizestr);
    free(hpstr);
    free(vpstr);

    return (ascii);
}

/* Return the number of DNS hierarchy levels in the name. */
int dn_count_labels(const char* name) {
    size_t len, i, count;

    len = strlen(name);
    for (i = 0, count = 0; i < len; i++) {
        /* XXX need to check for \. or use named's nlabels(). */
        if (name[i] == '.') count++;
    }

    /* don't count initial wildcard */
    if (name[0] == '*')
        if (count) count--;

    /* don't count the null label for root. */
    /* if terminating '.' not found, must adjust */
    /* count to include last label */
    if (len > 0 && name[len - 1] != '.') count++;
    return (int) count;
}

/*
 * Make dates expressed in seconds-since-Jan-1-1970 easy to read.
 * SIG records are required to be printed like this, by the Secure DNS RFC.
 */
char* p_secstodate(u_long secs) {
    /* XXX nonreentrant */
    static char output[15]; /* YYYYMMDDHHMMSS and null */
    time_t myclock = secs;
    struct tm* mytime;
#ifdef HAVE_TIME_R
    struct tm res;

    mytime = gmtime_r(&myclock, &res);
#else
    mytime = gmtime(&myclock);
#endif
    mytime->tm_year += 1900;
    mytime->tm_mon += 1;
    snprintf(output, sizeof(output), "%04d%02d%02d%02d%02d%02d", mytime->tm_year, mytime->tm_mon,
             mytime->tm_mday, mytime->tm_hour, mytime->tm_min, mytime->tm_sec);
    return (output);
}