name.c

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/*
 * Copyright (C) 2004-2015  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1998-2003  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.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <ctype.h>
#include <stdlib.h>

#include <isc/buffer.h>
#include <isc/hash.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/print.h>
#include <isc/string.h>
#include <isc/thread.h>
#include <isc/util.h>

#include <dns/compress.h>
#include <dns/fixedname.h>
#include <dns/name.h>
#include <dns/result.h>

#define VALID_NAME(n)   ISC_MAGIC_VALID(n, DNS_NAME_MAGIC)

typedef enum {
        ft_init = 0,
        ft_start,
        ft_ordinary,
        ft_initialescape,
        ft_escape,
        ft_escdecimal,
        ft_at
} ft_state;

typedef enum {
        fw_start = 0,
        fw_ordinary,
        fw_newcurrent
} fw_state;

static char digitvalue[256] = {
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
         0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1, /*64*/
        -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
        -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
};

static unsigned char maptolower[] = {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
        0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
        0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
        0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
        0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
        0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
        0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
        0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
        0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
        0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
        0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
        0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
        0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
        0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
        0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
        0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
        0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
        0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
        0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
        0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
        0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
        0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
        0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
        0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
        0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
        0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
        0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
        0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
        0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
        0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
        0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};

#define CONVERTTOASCII(c)
#define CONVERTFROMASCII(c)

#define INIT_OFFSETS(name, var, default) \
        if (name->offsets != NULL) \
                var = name->offsets; \
        else \
                var = default;

#define SETUP_OFFSETS(name, var, default) \
        if (name->offsets != NULL) \
                var = name->offsets; \
        else { \
                var = default; \
                set_offsets(name, var, NULL); \
        }

/*%
 * Note:  If additional attributes are added that should not be set for
 *        empty names, MAKE_EMPTY() must be changed so it clears them.
 */
#define MAKE_EMPTY(name) \
do { \
        name->ndata = NULL; \
        name->length = 0; \
        name->labels = 0; \
        name->attributes &= ~DNS_NAMEATTR_ABSOLUTE; \
} while (0);

/*%
 * A name is "bindable" if it can be set to point to a new value, i.e.
 * name->ndata and name->length may be changed.
 */
#define BINDABLE(name) \
        ((name->attributes & (DNS_NAMEATTR_READONLY|DNS_NAMEATTR_DYNAMIC)) \
         == 0)

/*%
 * Note that the name data must be a char array, not a string
 * literal, to avoid compiler warnings about discarding
 * the const attribute of a string.
 */
static unsigned char root_ndata[] = { '\0' };
static unsigned char root_offsets[] = { 0 };

static dns_name_t root =
{
        DNS_NAME_MAGIC,
        root_ndata, 1, 1,
        DNS_NAMEATTR_READONLY | DNS_NAMEATTR_ABSOLUTE,
        root_offsets, NULL,
        {(void *)-1, (void *)-1},
        {NULL, NULL}
};

/* XXXDCL make const? */
LIBDNS_EXTERNAL_DATA dns_name_t *dns_rootname = &root;

static unsigned char wild_ndata[] = { '\001', '*' };
static unsigned char wild_offsets[] = { 0 };

static dns_name_t wild =
{
        DNS_NAME_MAGIC,
        wild_ndata, 2, 1,
        DNS_NAMEATTR_READONLY,
        wild_offsets, NULL,
        {(void *)-1, (void *)-1},
        {NULL, NULL}
};

/* XXXDCL make const? */
LIBDNS_EXTERNAL_DATA dns_name_t *dns_wildcardname = &wild;

unsigned int
dns_fullname_hash(dns_name_t *name, isc_boolean_t case_sensitive);

/*
 * dns_name_t to text post-conversion procedure.
 */
#ifdef ISC_PLATFORM_USETHREADS
static int thread_key_initialized = 0;
static isc_mutex_t thread_key_mutex;
static isc_mem_t *thread_key_mctx = NULL;
static isc_thread_key_t totext_filter_proc_key;
static isc_once_t once = ISC_ONCE_INIT;
#else
static dns_name_totextfilter_t totext_filter_proc = NULL;
#endif

static void
set_offsets(const dns_name_t *name, unsigned char *offsets,
            dns_name_t *set_name);

void
dns_name_init(dns_name_t *name, unsigned char *offsets) {
        /*
         * Initialize 'name'.
         */
        DNS_NAME_INIT(name, offsets);
}

void
dns_name_reset(dns_name_t *name) {
        REQUIRE(VALID_NAME(name));
        REQUIRE(BINDABLE(name));

        DNS_NAME_RESET(name);
}

void
dns_name_invalidate(dns_name_t *name) {
        /*
         * Make 'name' invalid.
         */

        REQUIRE(VALID_NAME(name));

        name->magic = 0;
        name->ndata = NULL;
        name->length = 0;
        name->labels = 0;
        name->attributes = 0;
        name->offsets = NULL;
        name->buffer = NULL;
        ISC_LINK_INIT(name, link);
}

isc_boolean_t
dns_name_isvalid(const dns_name_t *name) {
        unsigned char *ndata, *offsets;
        unsigned int offset, count, length, nlabels;

        if (!VALID_NAME(name))
                return (ISC_FALSE);

        if (name->length > 255U || name->labels > 127U)
                return (ISC_FALSE);

        ndata = name->ndata;
        length = name->length;
        offsets = name->offsets;
        offset = 0;
        nlabels = 0;

        while (offset != length) {
                count = *ndata;
                if (count > 63U)
                        return (ISC_FALSE);
                if (offsets != NULL && offsets[nlabels] != offset)
                        return (ISC_FALSE);

                nlabels++;
                offset += count + 1;
                ndata += count + 1;
                if (offset > length)
                        return (ISC_FALSE);

                if (count == 0)
                        break;
        }

        if (nlabels != name->labels || offset != name->length)
                return (ISC_FALSE);

        return (ISC_TRUE);
}

void
dns_name_setbuffer(dns_name_t *name, isc_buffer_t *buffer) {
        /*
         * Dedicate a buffer for use with 'name'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE((buffer != NULL && name->buffer == NULL) ||
                (buffer == NULL));

        name->buffer = buffer;
}

isc_boolean_t
dns_name_hasbuffer(const dns_name_t *name) {
        /*
         * Does 'name' have a dedicated buffer?
         */

        REQUIRE(VALID_NAME(name));

        if (name->buffer != NULL)
                return (ISC_TRUE);

        return (ISC_FALSE);
}

isc_boolean_t
dns_name_isabsolute(const dns_name_t *name) {

        /*
         * Does 'name' end in the root label?
         */

        REQUIRE(VALID_NAME(name));

        if ((name->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                return (ISC_TRUE);
        return (ISC_FALSE);
}

#define hyphenchar(c) ((c) == 0x2d)
#define asterchar(c) ((c) == 0x2a)
#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
                      || ((c) >= 0x61 && (c) <= 0x7a))
#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
#define borderchar(c) (alphachar(c) || digitchar(c))
#define middlechar(c) (borderchar(c) || hyphenchar(c))
#define domainchar(c) ((c) > 0x20 && (c) < 0x7f)

isc_boolean_t
dns_name_ismailbox(const dns_name_t *name) {
        unsigned char *ndata, ch;
        unsigned int n;
        isc_boolean_t first;

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);
        REQUIRE(name->attributes & DNS_NAMEATTR_ABSOLUTE);

        /*
         * Root label.
         */
        if (name->length == 1)
                return (ISC_TRUE);

        ndata = name->ndata;
        n = *ndata++;
        INSIST(n <= 63);
        while (n--) {
                ch = *ndata++;
                if (!domainchar(ch))
                        return (ISC_FALSE);
        }

        if (ndata == name->ndata + name->length)
                return (ISC_FALSE);

        /*
         * RFC292/RFC1123 hostname.
         */
        while (ndata < (name->ndata + name->length)) {
                n = *ndata++;
                INSIST(n <= 63);
                first = ISC_TRUE;
                while (n--) {
                        ch = *ndata++;
                        if (first || n == 0) {
                                if (!borderchar(ch))
                                        return (ISC_FALSE);
                        } else {
                                if (!middlechar(ch))
                                        return (ISC_FALSE);
                        }
                        first = ISC_FALSE;
                }
        }
        return (ISC_TRUE);
}

isc_boolean_t
dns_name_ishostname(const dns_name_t *name, isc_boolean_t wildcard) {
        unsigned char *ndata, ch;
        unsigned int n;
        isc_boolean_t first;

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);
        REQUIRE(name->attributes & DNS_NAMEATTR_ABSOLUTE);

        /*
         * Root label.
         */
        if (name->length == 1)
                return (ISC_TRUE);

        /*
         * Skip wildcard if this is a ownername.
         */
        ndata = name->ndata;
        if (wildcard && ndata[0] == 1 && ndata[1] == '*')
                ndata += 2;

        /*
         * RFC292/RFC1123 hostname.
         */
        while (ndata < (name->ndata + name->length)) {
                n = *ndata++;
                INSIST(n <= 63);
                first = ISC_TRUE;
                while (n--) {
                        ch = *ndata++;
                        if (first || n == 0) {
                                if (!borderchar(ch))
                                        return (ISC_FALSE);
                        } else {
                                if (!middlechar(ch))
                                        return (ISC_FALSE);
                        }
                        first = ISC_FALSE;
                }
        }
        return (ISC_TRUE);
}

isc_boolean_t
dns_name_iswildcard(const dns_name_t *name) {
        unsigned char *ndata;

        /*
         * Is 'name' a wildcard name?
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);

        if (name->length >= 2) {
                ndata = name->ndata;
                if (ndata[0] == 1 && ndata[1] == '*')
                        return (ISC_TRUE);
        }

        return (ISC_FALSE);
}

isc_boolean_t
dns_name_internalwildcard(const dns_name_t *name) {
        unsigned char *ndata;
        unsigned int count;
        unsigned int label;

        /*
         * Does 'name' contain a internal wildcard?
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);

        /*
         * Skip first label.
         */
        ndata = name->ndata;
        count = *ndata++;
        INSIST(count <= 63);
        ndata += count;
        label = 1;
        /*
         * Check all but the last of the remaining labels.
         */
        while (label + 1 < name->labels) {
                count = *ndata++;
                INSIST(count <= 63);
                if (count == 1 && *ndata == '*')
                        return (ISC_TRUE);
                ndata += count;
                label++;
        }
        return (ISC_FALSE);
}

static inline unsigned int
name_hash(dns_name_t *name, isc_boolean_t case_sensitive) {
        unsigned int length;
        const unsigned char *s;
        unsigned int h = 0;
        unsigned char c;

        length = name->length;
        if (length > 16)
                length = 16;

        /*
         * This hash function is similar to the one Ousterhout
         * uses in Tcl.
         */
        s = name->ndata;
        if (case_sensitive) {
                while (length > 0) {
                        h += ( h << 3 ) + *s;
                        s++;
                        length--;
                }
        } else {
                while (length > 0) {
                        c = maptolower[*s];
                        h += ( h << 3 ) + c;
                        s++;
                        length--;
                }
        }

        return (h);
}

unsigned int
dns_name_hash(dns_name_t *name, isc_boolean_t case_sensitive) {
        /*
         * Provide a hash value for 'name'.
         */
        REQUIRE(VALID_NAME(name));

        if (name->labels == 0)
                return (0);

        return (name_hash(name, case_sensitive));
}

unsigned int
dns_name_fullhash(dns_name_t *name, isc_boolean_t case_sensitive) {
        /*
         * Provide a hash value for 'name'.
         */
        REQUIRE(VALID_NAME(name));

        if (name->labels == 0)
                return (0);

        return (isc_hash_calc((const unsigned char *)name->ndata,
                              name->length, case_sensitive));
}

unsigned int
dns_fullname_hash(dns_name_t *name, isc_boolean_t case_sensitive) {
        /*
         * This function was deprecated due to the breakage of the name space
         * convention.  We only keep this internally to provide binary backward
         * compatibility.
         */
        REQUIRE(VALID_NAME(name));

        return (dns_name_fullhash(name, case_sensitive));
}

unsigned int
dns_name_hashbylabel(dns_name_t *name, isc_boolean_t case_sensitive) {
        unsigned char *offsets;
        dns_offsets_t odata;
        dns_name_t tname;
        unsigned int h = 0;
        unsigned int i;

        /*
         * Provide a hash value for 'name'.
         */
        REQUIRE(VALID_NAME(name));

        if (name->labels == 0)
                return (0);
        else if (name->labels == 1)
                return (name_hash(name, case_sensitive));

        SETUP_OFFSETS(name, offsets, odata);
        DNS_NAME_INIT(&tname, NULL);
        tname.labels = 1;
        h = 0;
        for (i = 0; i < name->labels; i++) {
                tname.ndata = name->ndata + offsets[i];
                if (i == name->labels - 1)
                        tname.length = name->length - offsets[i];
                else
                        tname.length = offsets[i + 1] - offsets[i];
                h += name_hash(&tname, case_sensitive);
        }

        return (h);
}

dns_namereln_t
dns_name_fullcompare(const dns_name_t *name1, const dns_name_t *name2,
                     int *orderp, unsigned int *nlabelsp)
{
        unsigned int l1, l2, l, count1, count2, count, nlabels;
        int cdiff, ldiff, chdiff;
        unsigned char *label1, *label2;
        unsigned char *offsets1, *offsets2;
        dns_offsets_t odata1, odata2;
        dns_namereln_t namereln = dns_namereln_none;

        /*
         * Determine the relative ordering under the DNSSEC order relation of
         * 'name1' and 'name2', and also determine the hierarchical
         * relationship of the names.
         *
         * Note: It makes no sense for one of the names to be relative and the
         * other absolute.  If both names are relative, then to be meaningfully
         * compared the caller must ensure that they are both relative to the
         * same domain.
         */

        REQUIRE(VALID_NAME(name1));
        REQUIRE(VALID_NAME(name2));
        REQUIRE(orderp != NULL);
        REQUIRE(nlabelsp != NULL);
        /*
         * Either name1 is absolute and name2 is absolute, or neither is.
         */
        REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) ==
                (name2->attributes & DNS_NAMEATTR_ABSOLUTE));

        if (name1 == name2) {
                *orderp = 0;
                *nlabelsp = name1->labels;
                return (dns_namereln_equal);
        }

        SETUP_OFFSETS(name1, offsets1, odata1);
        SETUP_OFFSETS(name2, offsets2, odata2);

        nlabels = 0;
        l1 = name1->labels;
        l2 = name2->labels;
        if (l2 > l1) {
                l = l1;
                ldiff = 0 - (l2 - l1);
        } else {
                l = l2;
                ldiff = l1 - l2;
        }

        while (l > 0) {
                l--;
                l1--;
                l2--;
                label1 = &name1->ndata[offsets1[l1]];
                label2 = &name2->ndata[offsets2[l2]];
                count1 = *label1++;
                count2 = *label2++;

                /*
                 * We dropped bitstring labels, and we don't support any
                 * other extended label types.
                 */
                INSIST(count1 <= 63 && count2 <= 63);

                cdiff = (int)count1 - (int)count2;
                if (cdiff < 0)
                        count = count1;
                else
                        count = count2;

                while (count > 0) {
                        chdiff = (int)maptolower[*label1] -
                            (int)maptolower[*label2];
                        if (chdiff != 0) {
                                *orderp = chdiff;
                                goto done;
                        }
                        count--;
                        label1++;
                        label2++;
                }
                if (cdiff != 0) {
                        *orderp = cdiff;
                        goto done;
                }
                nlabels++;
        }

        *orderp = ldiff;
        if (ldiff < 0)
                namereln = dns_namereln_contains;
        else if (ldiff > 0)
                namereln = dns_namereln_subdomain;
        else
                namereln = dns_namereln_equal;

 done:
        *nlabelsp = nlabels;

        if (nlabels > 0 && namereln == dns_namereln_none)
                namereln = dns_namereln_commonancestor;

        return (namereln);
}

int
dns_name_compare(const dns_name_t *name1, const dns_name_t *name2) {
        int order;
        unsigned int nlabels;

        /*
         * Determine the relative ordering under the DNSSEC order relation of
         * 'name1' and 'name2'.
         *
         * Note: It makes no sense for one of the names to be relative and the
         * other absolute.  If both names are relative, then to be meaningfully
         * compared the caller must ensure that they are both relative to the
         * same domain.
         */

        (void)dns_name_fullcompare(name1, name2, &order, &nlabels);

        return (order);
}

isc_boolean_t
dns_name_equal(const dns_name_t *name1, const dns_name_t *name2) {
        unsigned int l, count;
        unsigned char c;
        unsigned char *label1, *label2;

        /*
         * Are 'name1' and 'name2' equal?
         *
         * Note: It makes no sense for one of the names to be relative and the
         * other absolute.  If both names are relative, then to be meaningfully
         * compared the caller must ensure that they are both relative to the
         * same domain.
         */

        REQUIRE(VALID_NAME(name1));
        REQUIRE(VALID_NAME(name2));
        /*
         * Either name1 is absolute and name2 is absolute, or neither is.
         */
        REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) ==
                (name2->attributes & DNS_NAMEATTR_ABSOLUTE));

        if (name1 == name2)
                return (ISC_TRUE);

        if (name1->length != name2->length)
                return (ISC_FALSE);

        l = name1->labels;

        if (l != name2->labels)
                return (ISC_FALSE);

        label1 = name1->ndata;
        label2 = name2->ndata;
        while (l > 0) {
                l--;
                count = *label1++;
                if (count != *label2++)
                        return (ISC_FALSE);

                INSIST(count <= 63); /* no bitstring support */

                while (count > 0) {
                        count--;
                        c = maptolower[*label1++];
                        if (c != maptolower[*label2++])
                                return (ISC_FALSE);
                }
        }

        return (ISC_TRUE);
}

isc_boolean_t
dns_name_caseequal(const dns_name_t *name1, const dns_name_t *name2) {

        /*
         * Are 'name1' and 'name2' equal?
         *
         * Note: It makes no sense for one of the names to be relative and the
         * other absolute.  If both names are relative, then to be meaningfully
         * compared the caller must ensure that they are both relative to the
         * same domain.
         */

        REQUIRE(VALID_NAME(name1));
        REQUIRE(VALID_NAME(name2));
        /*
         * Either name1 is absolute and name2 is absolute, or neither is.
         */
        REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) ==
                (name2->attributes & DNS_NAMEATTR_ABSOLUTE));

        if (name1->length != name2->length)
                return (ISC_FALSE);

        if (memcmp(name1->ndata, name2->ndata, name1->length) != 0)
                return (ISC_FALSE);

        return (ISC_TRUE);
}

int
dns_name_rdatacompare(const dns_name_t *name1, const dns_name_t *name2) {
        unsigned int l1, l2, l, count1, count2, count;
        unsigned char c1, c2;
        unsigned char *label1, *label2;

        /*
         * Compare two absolute names as rdata.
         */

        REQUIRE(VALID_NAME(name1));
        REQUIRE(name1->labels > 0);
        REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) != 0);
        REQUIRE(VALID_NAME(name2));
        REQUIRE(name2->labels > 0);
        REQUIRE((name2->attributes & DNS_NAMEATTR_ABSOLUTE) != 0);

        l1 = name1->labels;
        l2 = name2->labels;

        l = (l1 < l2) ? l1 : l2;

        label1 = name1->ndata;
        label2 = name2->ndata;
        while (l > 0) {
                l--;
                count1 = *label1++;
                count2 = *label2++;

                /* no bitstring support */
                INSIST(count1 <= 63 && count2 <= 63);

                if (count1 != count2)
                        return ((count1 < count2) ? -1 : 1);
                count = count1;
                while (count > 0) {
                        count--;
                        c1 = maptolower[*label1++];
                        c2 = maptolower[*label2++];
                        if (c1 < c2)
                                return (-1);
                        else if (c1 > c2)
                                return (1);
                }
        }

        /*
         * If one name had more labels than the other, their common
         * prefix must have been different because the shorter name
         * ended with the root label and the longer one can't have
         * a root label in the middle of it.  Therefore, if we get
         * to this point, the lengths must be equal.
         */
        INSIST(l1 == l2);

        return (0);
}

isc_boolean_t
dns_name_issubdomain(const dns_name_t *name1, const dns_name_t *name2) {
        int order;
        unsigned int nlabels;
        dns_namereln_t namereln;

        /*
         * Is 'name1' a subdomain of 'name2'?
         *
         * Note: It makes no sense for one of the names to be relative and the
         * other absolute.  If both names are relative, then to be meaningfully
         * compared the caller must ensure that they are both relative to the
         * same domain.
         */

        namereln = dns_name_fullcompare(name1, name2, &order, &nlabels);
        if (namereln == dns_namereln_subdomain ||
            namereln == dns_namereln_equal)
                return (ISC_TRUE);

        return (ISC_FALSE);
}

isc_boolean_t
dns_name_matcheswildcard(const dns_name_t *name, const dns_name_t *wname) {
        int order;
        unsigned int nlabels, labels;
        dns_name_t tname;

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);
        REQUIRE(VALID_NAME(wname));
        labels = wname->labels;
        REQUIRE(labels > 0);
        REQUIRE(dns_name_iswildcard(wname));

#if defined(__clang__)  && \
       ( __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 2))
        memset(&tname, 0, sizeof(tname));
#endif
        DNS_NAME_INIT(&tname, NULL);
        dns_name_getlabelsequence(wname, 1, labels - 1, &tname);
        if (dns_name_fullcompare(name, &tname, &order, &nlabels) ==
            dns_namereln_subdomain)
                return (ISC_TRUE);
        return (ISC_FALSE);
}

unsigned int
dns_name_countlabels(const dns_name_t *name) {
        /*
         * How many labels does 'name' have?
         */

        REQUIRE(VALID_NAME(name));

        ENSURE(name->labels <= 128);

        return (name->labels);
}

void
dns_name_getlabel(const dns_name_t *name, unsigned int n, dns_label_t *label) {
        unsigned char *offsets;
        dns_offsets_t odata;

        /*
         * Make 'label' refer to the 'n'th least significant label of 'name'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(name->labels > 0);
        REQUIRE(n < name->labels);
        REQUIRE(label != NULL);

        SETUP_OFFSETS(name, offsets, odata);

        label->base = &name->ndata[offsets[n]];
        if (n == name->labels - 1)
                label->length = name->length - offsets[n];
        else
                label->length = offsets[n + 1] - offsets[n];
}

void
dns_name_getlabelsequence(const dns_name_t *source,
                          unsigned int first, unsigned int n,
                          dns_name_t *target)
{
        unsigned char *offsets;
        dns_offsets_t odata;
        unsigned int firstoffset, endoffset;

        /*
         * Make 'target' refer to the 'n' labels including and following
         * 'first' in 'source'.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(VALID_NAME(target));
        REQUIRE(first <= source->labels);
        REQUIRE(n <= source->labels - first); /* note first+n could overflow */
        REQUIRE(BINDABLE(target));

        SETUP_OFFSETS(source, offsets, odata);

        if (first == source->labels)
                firstoffset = source->length;
        else
                firstoffset = offsets[first];

        if (first + n == source->labels)
                endoffset = source->length;
        else
                endoffset = offsets[first + n];

        target->ndata = &source->ndata[firstoffset];
        target->length = endoffset - firstoffset;

        if (first + n == source->labels && n > 0 &&
            (source->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                target->attributes |= DNS_NAMEATTR_ABSOLUTE;
        else
                target->attributes &= ~DNS_NAMEATTR_ABSOLUTE;

        target->labels = n;

        /*
         * If source and target are the same, and we're making target
         * a prefix of source, the offsets table is correct already
         * so we don't need to call set_offsets().
         */
        if (target->offsets != NULL &&
            (target != source || first != 0))
                set_offsets(target, target->offsets, NULL);
}

void
dns_name_clone(const dns_name_t *source, dns_name_t *target) {

        /*
         * Make 'target' refer to the same name as 'source'.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(VALID_NAME(target));
        REQUIRE(BINDABLE(target));

        target->ndata = source->ndata;
        target->length = source->length;
        target->labels = source->labels;
        target->attributes = source->attributes &
                (unsigned int)~(DNS_NAMEATTR_READONLY | DNS_NAMEATTR_DYNAMIC |
                                DNS_NAMEATTR_DYNOFFSETS);
        if (target->offsets != NULL && source->labels > 0) {
                if (source->offsets != NULL)
                        memmove(target->offsets, source->offsets,
                                source->labels);
                else
                        set_offsets(target, target->offsets, NULL);
        }
}

void
dns_name_fromregion(dns_name_t *name, const isc_region_t *r) {
        unsigned char *offsets;
        dns_offsets_t odata;
        unsigned int len;
        isc_region_t r2;

        /*
         * Make 'name' refer to region 'r'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(r != NULL);
        REQUIRE(BINDABLE(name));

        INIT_OFFSETS(name, offsets, odata);

        if (name->buffer != NULL) {
                isc_buffer_clear(name->buffer);
                isc_buffer_availableregion(name->buffer, &r2);
                len = (r->length < r2.length) ? r->length : r2.length;
                if (len > DNS_NAME_MAXWIRE)
                        len = DNS_NAME_MAXWIRE;
                memmove(r2.base, r->base, len);
                name->ndata = r2.base;
                name->length = len;
        } else {
                name->ndata = r->base;
                name->length = (r->length <= DNS_NAME_MAXWIRE) ?
                        r->length : DNS_NAME_MAXWIRE;
        }

        if (r->length > 0)
                set_offsets(name, offsets, name);
        else {
                name->labels = 0;
                name->attributes &= ~DNS_NAMEATTR_ABSOLUTE;
        }

        if (name->buffer != NULL)
                isc_buffer_add(name->buffer, name->length);
}

void
dns_name_toregion(dns_name_t *name, isc_region_t *r) {
        /*
         * Make 'r' refer to 'name'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(r != NULL);

        DNS_NAME_TOREGION(name, r);
}

isc_result_t
dns_name_fromtext(dns_name_t *name, isc_buffer_t *source,
                  const dns_name_t *origin, unsigned int options,
                  isc_buffer_t *target)
{
        unsigned char *ndata, *label = NULL;
        char *tdata;
        char c;
        ft_state state;
        unsigned int value = 0, count = 0;
        unsigned int n1 = 0, n2 = 0;
        unsigned int tlen, nrem, nused, digits = 0, labels, tused;
        isc_boolean_t done;
        unsigned char *offsets;
        dns_offsets_t odata;
        isc_boolean_t downcase;

        /*
         * Convert the textual representation of a DNS name at source
         * into uncompressed wire form stored in target.
         *
         * Notes:
         *      Relative domain names will have 'origin' appended to them
         *      unless 'origin' is NULL, in which case relative domain names
         *      will remain relative.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(ISC_BUFFER_VALID(source));
        REQUIRE((target != NULL && ISC_BUFFER_VALID(target)) ||
                (target == NULL && ISC_BUFFER_VALID(name->buffer)));

        downcase = ISC_TF((options & DNS_NAME_DOWNCASE) != 0);

        if (target == NULL && name->buffer != NULL) {
                target = name->buffer;
                isc_buffer_clear(target);
        }

        REQUIRE(BINDABLE(name));

        INIT_OFFSETS(name, offsets, odata);
        offsets[0] = 0;

        /*
         * Make 'name' empty in case of failure.
         */
        MAKE_EMPTY(name);

        /*
         * Set up the state machine.
         */
        tdata = (char *)source->base + source->current;
        tlen = isc_buffer_remaininglength(source);
        tused = 0;
        ndata = isc_buffer_used(target);
        nrem = isc_buffer_availablelength(target);
        if (nrem > 255)
                nrem = 255;
        nused = 0;
        labels = 0;
        done = ISC_FALSE;
        state = ft_init;

        while (nrem > 0 && tlen > 0 && !done) {
                c = *tdata++;
                tlen--;
                tused++;

                switch (state) {
                case ft_init:
                        /*
                         * Is this the root name?
                         */
                        if (c == '.') {
                                if (tlen != 0)
                                        return (DNS_R_EMPTYLABEL);
                                labels++;
                                *ndata++ = 0;
                                nrem--;
                                nused++;
                                done = ISC_TRUE;
                                break;
                        }
                        if (c == '@' && tlen == 0) {
                                state = ft_at;
                                break;
                        }

                        /* FALLTHROUGH */
                case ft_start:
                        label = ndata;
                        ndata++;
                        nrem--;
                        nused++;
                        count = 0;
                        if (c == '\\') {
                                state = ft_initialescape;
                                break;
                        }
                        state = ft_ordinary;
                        if (nrem == 0)
                                return (ISC_R_NOSPACE);
                        /* FALLTHROUGH */
                case ft_ordinary:
                        if (c == '.') {
                                if (count == 0)
                                        return (DNS_R_EMPTYLABEL);
                                *label = count;
                                labels++;
                                INSIST(labels <= 127);
                                offsets[labels] = nused;
                                if (tlen == 0) {
                                        labels++;
                                        *ndata++ = 0;
                                        nrem--;
                                        nused++;
                                        done = ISC_TRUE;
                                }
                                state = ft_start;
                        } else if (c == '\\') {
                                state = ft_escape;
                        } else {
                                if (count >= 63)
                                        return (DNS_R_LABELTOOLONG);
                                count++;
                                CONVERTTOASCII(c);
                                if (downcase)
                                        c = maptolower[c & 0xff];
                                *ndata++ = c;
                                nrem--;
                                nused++;
                        }
                        break;
                case ft_initialescape:
                        if (c == '[') {
                                /*
                                 * This looks like a bitstring label, which
                                 * was deprecated.  Intentionally drop it.
                                 */
                                return (DNS_R_BADLABELTYPE);
                        }
                        state = ft_escape;
                        POST(state);
                        /* FALLTHROUGH */
                case ft_escape:
                        if (!isdigit(c & 0xff)) {
                                if (count >= 63)
                                        return (DNS_R_LABELTOOLONG);
                                count++;
                                CONVERTTOASCII(c);
                                if (downcase)
                                        c = maptolower[c & 0xff];
                                *ndata++ = c;
                                nrem--;
                                nused++;
                                state = ft_ordinary;
                                break;
                        }
                        digits = 0;
                        value = 0;
                        state = ft_escdecimal;
                        /* FALLTHROUGH */
                case ft_escdecimal:
                        if (!isdigit(c & 0xff))
                                return (DNS_R_BADESCAPE);
                        value *= 10;
                        value += digitvalue[c & 0xff];
                        digits++;
                        if (digits == 3) {
                                if (value > 255)
                                        return (DNS_R_BADESCAPE);
                                if (count >= 63)
                                        return (DNS_R_LABELTOOLONG);
                                count++;
                                if (downcase)
                                        value = maptolower[value];
                                *ndata++ = value;
                                nrem--;
                                nused++;
                                state = ft_ordinary;
                        }
                        break;
                default:
                        FATAL_ERROR(__FILE__, __LINE__,
                                    "Unexpected state %d", state);
                        /* Does not return. */
                }
        }

        if (!done) {
                if (nrem == 0)
                        return (ISC_R_NOSPACE);
                INSIST(tlen == 0);
                if (state != ft_ordinary && state != ft_at)
                        return (ISC_R_UNEXPECTEDEND);
                if (state == ft_ordinary) {
                        INSIST(count != 0);
                        *label = count;
                        labels++;
                        INSIST(labels <= 127);
                        offsets[labels] = nused;
                }
                if (origin != NULL) {
                        if (nrem < origin->length)
                                return (ISC_R_NOSPACE);
                        label = origin->ndata;
                        n1 = origin->length;
                        nrem -= n1;
                        POST(nrem);
                        while (n1 > 0) {
                                n2 = *label++;
                                INSIST(n2 <= 63); /* no bitstring support */
                                *ndata++ = n2;
                                n1 -= n2 + 1;
                                nused += n2 + 1;
                                while (n2 > 0) {
                                        c = *label++;
                                        if (downcase)
                                                c = maptolower[c & 0xff];
                                        *ndata++ = c;
                                        n2--;
                                }
                                labels++;
                                if (n1 > 0) {
                                        INSIST(labels <= 127);
                                        offsets[labels] = nused;
                                }
                        }
                        if ((origin->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                                name->attributes |= DNS_NAMEATTR_ABSOLUTE;
                }
        } else
                name->attributes |= DNS_NAMEATTR_ABSOLUTE;

        name->ndata = (unsigned char *)target->base + target->used;
        name->labels = labels;
        name->length = nused;

        isc_buffer_forward(source, tused);
        isc_buffer_add(target, name->length);

        return (ISC_R_SUCCESS);
}

#ifdef ISC_PLATFORM_USETHREADS
static void
free_specific(void *arg) {
        dns_name_totextfilter_t *mem = arg;
        isc_mem_put(thread_key_mctx, mem, sizeof(*mem));
        /* Stop use being called again. */
        (void)isc_thread_key_setspecific(totext_filter_proc_key, NULL);
}

static void
thread_key_mutex_init(void) {
        RUNTIME_CHECK(isc_mutex_init(&thread_key_mutex) == ISC_R_SUCCESS);
}

static isc_result_t
totext_filter_proc_key_init(void) {
        isc_result_t result;

        /*
         * We need the call to isc_once_do() to support profiled mutex
         * otherwise thread_key_mutex could be initialized at compile time.
         */
        result = isc_once_do(&once, thread_key_mutex_init);
        if (result != ISC_R_SUCCESS)
                return (result);

        if (!thread_key_initialized) {
                LOCK(&thread_key_mutex);
                if (thread_key_mctx == NULL)
                        result = isc_mem_create2(0, 0, &thread_key_mctx, 0);
                if (result != ISC_R_SUCCESS)
                        goto unlock;
                isc_mem_setname(thread_key_mctx, "threadkey", NULL);
                isc_mem_setdestroycheck(thread_key_mctx, ISC_FALSE);

                if (!thread_key_initialized &&
                     isc_thread_key_create(&totext_filter_proc_key,
                                           free_specific) != 0) {
                        result = ISC_R_FAILURE;
                        isc_mem_detach(&thread_key_mctx);
                } else
                        thread_key_initialized = 1;
 unlock:
                UNLOCK(&thread_key_mutex);
        }
        return (result);
}
#endif

isc_result_t
dns_name_totext(const dns_name_t *name, isc_boolean_t omit_final_dot,
                isc_buffer_t *target)
{
        unsigned int options = DNS_NAME_MASTERFILE;

        if (omit_final_dot)
                options |= DNS_NAME_OMITFINALDOT;
        return (dns_name_totext2(name, options, target));
}

isc_result_t
dns_name_toprincipal(const dns_name_t *name, isc_buffer_t *target) {
        return (dns_name_totext2(name, DNS_NAME_OMITFINALDOT, target));
}

isc_result_t
dns_name_totext2(const dns_name_t *name, unsigned int options,
                 isc_buffer_t *target)
{
        unsigned char *ndata;
        char *tdata;
        unsigned int nlen, tlen;
        unsigned char c;
        unsigned int trem, count;
        unsigned int labels;
        isc_boolean_t saw_root = ISC_FALSE;
        unsigned int oused = target->used;
#ifdef ISC_PLATFORM_USETHREADS
        dns_name_totextfilter_t *mem;
        dns_name_totextfilter_t totext_filter_proc = NULL;
        isc_result_t result;
#endif
        isc_boolean_t omit_final_dot =
                ISC_TF(options & DNS_NAME_OMITFINALDOT);

        /*
         * This function assumes the name is in proper uncompressed
         * wire format.
         */
        REQUIRE(VALID_NAME(name));
        REQUIRE(ISC_BUFFER_VALID(target));

#ifdef ISC_PLATFORM_USETHREADS
        result = totext_filter_proc_key_init();
        if (result != ISC_R_SUCCESS)
                return (result);
#endif
        ndata = name->ndata;
        nlen = name->length;
        labels = name->labels;
        tdata = isc_buffer_used(target);
        tlen = isc_buffer_availablelength(target);

        trem = tlen;

        if (labels == 0 && nlen == 0) {
                /*
                 * Special handling for an empty name.
                 */
                if (trem == 0)
                        return (ISC_R_NOSPACE);

                /*
                 * The names of these booleans are misleading in this case.
                 * This empty name is not necessarily from the root node of
                 * the DNS root zone, nor is a final dot going to be included.
                 * They need to be set this way, though, to keep the "@"
                 * from being trounced.
                 */
                saw_root = ISC_TRUE;
                omit_final_dot = ISC_FALSE;
                *tdata++ = '@';
                trem--;

                /*
                 * Skip the while() loop.
                 */
                nlen = 0;
        } else if (nlen == 1 && labels == 1 && *ndata == '\0') {
                /*
                 * Special handling for the root label.
                 */
                if (trem == 0)
                        return (ISC_R_NOSPACE);

                saw_root = ISC_TRUE;
                omit_final_dot = ISC_FALSE;
                *tdata++ = '.';
                trem--;

                /*
                 * Skip the while() loop.
                 */
                nlen = 0;
        }

        while (labels > 0 && nlen > 0 && trem > 0) {
                labels--;
                count = *ndata++;
                nlen--;
                if (count == 0) {
                        saw_root = ISC_TRUE;
                        break;
                }
                if (count < 64) {
                        INSIST(nlen >= count);
                        while (count > 0) {
                                c = *ndata;
                                switch (c) {
                                /* Special modifiers in zone files. */
                                case 0x40: /* '@' */
                                case 0x24: /* '$' */
                                        if ((options & DNS_NAME_MASTERFILE) == 0)
                                                goto no_escape;
                                        /* FALLTHROUGH */
                                case 0x22: /* '"' */
                                case 0x28: /* '(' */
                                case 0x29: /* ')' */
                                case 0x2E: /* '.' */
                                case 0x3B: /* ';' */
                                case 0x5C: /* '\\' */
                                        if (trem < 2)
                                                return (ISC_R_NOSPACE);
                                        *tdata++ = '\\';
                                        CONVERTFROMASCII(c);
                                        *tdata++ = c;
                                        ndata++;
                                        trem -= 2;
                                        nlen--;
                                        break;
                                no_escape:
                                default:
                                        if (c > 0x20 && c < 0x7f) {
                                                if (trem == 0)
                                                        return (ISC_R_NOSPACE);
                                                CONVERTFROMASCII(c);
                                                *tdata++ = c;
                                                ndata++;
                                                trem--;
                                                nlen--;
                                        } else {
                                                if (trem < 4)
                                                        return (ISC_R_NOSPACE);
                                                *tdata++ = 0x5c;
                                                *tdata++ = 0x30 +
                                                           ((c / 100) % 10);
                                                *tdata++ = 0x30 +
                                                           ((c / 10) % 10);
                                                *tdata++ = 0x30 + (c % 10);
                                                trem -= 4;
                                                ndata++;
                                                nlen--;
                                        }
                                }
                                count--;
                        }
                } else {
                        FATAL_ERROR(__FILE__, __LINE__,
                                    "Unexpected label type %02x", count);
                        /* NOTREACHED */
                }

                /*
                 * The following assumes names are absolute.  If not, we
                 * fix things up later.  Note that this means that in some
                 * cases one more byte of text buffer is required than is
                 * needed in the final output.
                 */
                if (trem == 0)
                        return (ISC_R_NOSPACE);
                *tdata++ = '.';
                trem--;
        }

        if (nlen != 0 && trem == 0)
                return (ISC_R_NOSPACE);

        if (!saw_root || omit_final_dot)
                trem++;

        isc_buffer_add(target, tlen - trem);

#ifdef ISC_PLATFORM_USETHREADS
        mem = isc_thread_key_getspecific(totext_filter_proc_key);
        if (mem != NULL)
                totext_filter_proc = *mem;
#endif
        if (totext_filter_proc != NULL)
                return ((*totext_filter_proc)(target, oused, saw_root));

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_name_tofilenametext(dns_name_t *name, isc_boolean_t omit_final_dot,
                        isc_buffer_t *target)
{
        unsigned char *ndata;
        char *tdata;
        unsigned int nlen, tlen;
        unsigned char c;
        unsigned int trem, count;
        unsigned int labels;

        /*
         * This function assumes the name is in proper uncompressed
         * wire format.
         */
        REQUIRE(VALID_NAME(name));
        REQUIRE((name->attributes & DNS_NAMEATTR_ABSOLUTE) != 0);
        REQUIRE(ISC_BUFFER_VALID(target));

        ndata = name->ndata;
        nlen = name->length;
        labels = name->labels;
        tdata = isc_buffer_used(target);
        tlen = isc_buffer_availablelength(target);

        trem = tlen;

        if (nlen == 1 && labels == 1 && *ndata == '\0') {
                /*
                 * Special handling for the root label.
                 */
                if (trem == 0)
                        return (ISC_R_NOSPACE);

                omit_final_dot = ISC_FALSE;
                *tdata++ = '.';
                trem--;

                /*
                 * Skip the while() loop.
                 */
                nlen = 0;
        }

        while (labels > 0 && nlen > 0 && trem > 0) {
                labels--;
                count = *ndata++;
                nlen--;
                if (count == 0)
                        break;
                if (count < 64) {
                        INSIST(nlen >= count);
                        while (count > 0) {
                                c = *ndata;
                                if ((c >= 0x30 && c <= 0x39) || /* digit */
                                    (c >= 0x41 && c <= 0x5A) || /* uppercase */
                                    (c >= 0x61 && c <= 0x7A) || /* lowercase */
                                    c == 0x2D ||                /* hyphen */
                                    c == 0x5F)                  /* underscore */
                                {
                                        if (trem == 0)
                                                return (ISC_R_NOSPACE);
                                        /* downcase */
                                        if (c >= 0x41 && c <= 0x5A)
                                                c += 0x20;
                                        CONVERTFROMASCII(c);
                                        *tdata++ = c;
                                        ndata++;
                                        trem--;
                                        nlen--;
                                } else {
                                        if (trem < 3)
                                                return (ISC_R_NOSPACE);
                                        sprintf(tdata, "%%%02X", c);
                                        tdata += 3;
                                        trem -= 3;
                                        ndata++;
                                        nlen--;
                                }
                                count--;
                        }
                } else {
                        FATAL_ERROR(__FILE__, __LINE__,
                                    "Unexpected label type %02x", count);
                        /* NOTREACHED */
                }

                /*
                 * The following assumes names are absolute.  If not, we
                 * fix things up later.  Note that this means that in some
                 * cases one more byte of text buffer is required than is
                 * needed in the final output.
                 */
                if (trem == 0)
                        return (ISC_R_NOSPACE);
                *tdata++ = '.';
                trem--;
        }

        if (nlen != 0 && trem == 0)
                return (ISC_R_NOSPACE);

        if (omit_final_dot)
                trem++;

        isc_buffer_add(target, tlen - trem);

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_name_downcase(dns_name_t *source, dns_name_t *name, isc_buffer_t *target) {
        unsigned char *sndata, *ndata;
        unsigned int nlen, count, labels;
        isc_buffer_t buffer;

        /*
         * Downcase 'source'.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(VALID_NAME(name));
        if (source == name) {
                REQUIRE((name->attributes & DNS_NAMEATTR_READONLY) == 0);
                isc_buffer_init(&buffer, source->ndata, source->length);
                target = &buffer;
                ndata = source->ndata;
        } else {
                REQUIRE(BINDABLE(name));
                REQUIRE((target != NULL && ISC_BUFFER_VALID(target)) ||
                        (target == NULL && ISC_BUFFER_VALID(name->buffer)));
                if (target == NULL) {
                        target = name->buffer;
                        isc_buffer_clear(name->buffer);
                }
                ndata = (unsigned char *)target->base + target->used;
                name->ndata = ndata;
        }

        sndata = source->ndata;
        nlen = source->length;
        labels = source->labels;

        if (nlen > (target->length - target->used)) {
                MAKE_EMPTY(name);
                return (ISC_R_NOSPACE);
        }

        while (labels > 0 && nlen > 0) {
                labels--;
                count = *sndata++;
                *ndata++ = count;
                nlen--;
                if (count < 64) {
                        INSIST(nlen >= count);
                        while (count > 0) {
                                *ndata++ = maptolower[(*sndata++)];
                                nlen--;
                                count--;
                        }
                } else {
                        FATAL_ERROR(__FILE__, __LINE__,
                                    "Unexpected label type %02x", count);
                        /* Does not return. */
                }
        }

        if (source != name) {
                name->labels = source->labels;
                name->length = source->length;
                if ((source->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                        name->attributes = DNS_NAMEATTR_ABSOLUTE;
                else
                        name->attributes = 0;
                if (name->labels > 0 && name->offsets != NULL)
                        set_offsets(name, name->offsets, NULL);
        }

        isc_buffer_add(target, name->length);

        return (ISC_R_SUCCESS);
}

static void
set_offsets(const dns_name_t *name, unsigned char *offsets,
            dns_name_t *set_name)
{
        unsigned int offset, count, length, nlabels;
        unsigned char *ndata;
        isc_boolean_t absolute;

        ndata = name->ndata;
        length = name->length;
        offset = 0;
        nlabels = 0;
        absolute = ISC_FALSE;
        while (offset != length) {
                INSIST(nlabels < 128);
                offsets[nlabels++] = offset;
                count = *ndata++;
                offset++;
                INSIST(count <= 63);
                offset += count;
                ndata += count;
                INSIST(offset <= length);
                if (count == 0) {
                        absolute = ISC_TRUE;
                        break;
                }
        }
        if (set_name != NULL) {
                INSIST(set_name == name);

                set_name->labels = nlabels;
                set_name->length = offset;
                if (absolute)
                        set_name->attributes |= DNS_NAMEATTR_ABSOLUTE;
                else
                        set_name->attributes &= ~DNS_NAMEATTR_ABSOLUTE;
        }
        INSIST(nlabels == name->labels);
        INSIST(offset == name->length);
}

isc_result_t
dns_name_fromwire(dns_name_t *name, isc_buffer_t *source,
                  dns_decompress_t *dctx, unsigned int options,
                  isc_buffer_t *target)
{
        unsigned char *cdata, *ndata;
        unsigned int cused; /* Bytes of compressed name data used */
        unsigned int nused, labels, n, nmax;
        unsigned int current, new_current, biggest_pointer;
        isc_boolean_t done;
        fw_state state = fw_start;
        unsigned int c;
        unsigned char *offsets;
        dns_offsets_t odata;
        isc_boolean_t downcase;
        isc_boolean_t seen_pointer;

        /*
         * Copy the possibly-compressed name at source into target,
         * decompressing it.  Loop prevention is performed by checking
         * the new pointer against biggest_pointer.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE((target != NULL && ISC_BUFFER_VALID(target)) ||
                (target == NULL && ISC_BUFFER_VALID(name->buffer)));

        downcase = ISC_TF((options & DNS_NAME_DOWNCASE) != 0);

        if (target == NULL && name->buffer != NULL) {
                target = name->buffer;
                isc_buffer_clear(target);
        }

        REQUIRE(dctx != NULL);
        REQUIRE(BINDABLE(name));

        INIT_OFFSETS(name, offsets, odata);

        /*
         * Make 'name' empty in case of failure.
         */
        MAKE_EMPTY(name);

        /*
         * Initialize things to make the compiler happy; they're not required.
         */
        n = 0;
        new_current = 0;

        /*
         * Set up.
         */
        labels = 0;
        done = ISC_FALSE;

        ndata = isc_buffer_used(target);
        nused = 0;
        seen_pointer = ISC_FALSE;

        /*
         * Find the maximum number of uncompressed target name
         * bytes we are willing to generate.  This is the smaller
         * of the available target buffer length and the
         * maximum legal domain name length (255).
         */
        nmax = isc_buffer_availablelength(target);
        if (nmax > DNS_NAME_MAXWIRE)
                nmax = DNS_NAME_MAXWIRE;

        cdata = isc_buffer_current(source);
        cused = 0;

        current = source->current;
        biggest_pointer = current;

        /*
         * Note:  The following code is not optimized for speed, but
         * rather for correctness.  Speed will be addressed in the future.
         */

        while (current < source->active && !done) {
                c = *cdata++;
                current++;
                if (!seen_pointer)
                        cused++;

                switch (state) {
                case fw_start:
                        if (c < 64) {
                                offsets[labels] = nused;
                                labels++;
                                if (nused + c + 1 > nmax)
                                        goto full;
                                nused += c + 1;
                                *ndata++ = c;
                                if (c == 0)
                                        done = ISC_TRUE;
                                n = c;
                                state = fw_ordinary;
                        } else if (c >= 128 && c < 192) {
                                /*
                                 * 14 bit local compression pointer.
                                 * Local compression is no longer an
                                 * IETF draft.
                                 */
                                return (DNS_R_BADLABELTYPE);
                        } else if (c >= 192) {
                                /*
                                 * Ordinary 14-bit pointer.
                                 */
                                if ((dctx->allowed & DNS_COMPRESS_GLOBAL14) ==
                                    0)
                                        return (DNS_R_DISALLOWED);
                                new_current = c & 0x3F;
                                state = fw_newcurrent;
                        } else
                                return (DNS_R_BADLABELTYPE);
                        break;
                case fw_ordinary:
                        if (downcase)
                                c = maptolower[c];
                        *ndata++ = c;
                        n--;
                        if (n == 0)
                                state = fw_start;
                        break;
                case fw_newcurrent:
                        new_current *= 256;
                        new_current += c;
                        if (new_current >= biggest_pointer)
                                return (DNS_R_BADPOINTER);
                        biggest_pointer = new_current;
                        current = new_current;
                        cdata = (unsigned char *)source->base + current;
                        seen_pointer = ISC_TRUE;
                        state = fw_start;
                        break;
                default:
                        FATAL_ERROR(__FILE__, __LINE__,
                                    "Unknown state %d", state);
                        /* Does not return. */
                }
        }

        if (!done)
                return (ISC_R_UNEXPECTEDEND);

        name->ndata = (unsigned char *)target->base + target->used;
        name->labels = labels;
        name->length = nused;
        name->attributes |= DNS_NAMEATTR_ABSOLUTE;

        isc_buffer_forward(source, cused);
        isc_buffer_add(target, name->length);

        return (ISC_R_SUCCESS);

 full:
        if (nmax == DNS_NAME_MAXWIRE)
                /*
                 * The name did not fit even though we had a buffer
                 * big enough to fit a maximum-length name.
                 */
                return (DNS_R_NAMETOOLONG);
        else
                /*
                 * The name might fit if only the caller could give us a
                 * big enough buffer.
                 */
                return (ISC_R_NOSPACE);
}

isc_result_t
dns_name_towire(const dns_name_t *name, dns_compress_t *cctx,
                isc_buffer_t *target)
{
        unsigned int methods;
        isc_uint16_t offset;
        dns_name_t gp;  /* Global compression prefix */
        isc_boolean_t gf;       /* Global compression target found */
        isc_uint16_t go;        /* Global compression offset */
        dns_offsets_t clo;
        dns_name_t clname;

        /*
         * Convert 'name' into wire format, compressing it as specified by the
         * compression context 'cctx', and storing the result in 'target'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(cctx != NULL);
        REQUIRE(ISC_BUFFER_VALID(target));

        /*
         * If 'name' doesn't have an offsets table, make a clone which
         * has one.
         */
        if (name->offsets == NULL) {
#if defined(__clang__)  && \
       ( __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 2))
                memset(&clname, 0, sizeof(clname));
#endif
                DNS_NAME_INIT(&clname, clo);
                dns_name_clone(name, &clname);
                name = &clname;
        }
        DNS_NAME_INIT(&gp, NULL);

        offset = target->used;  /*XXX*/

        methods = dns_compress_getmethods(cctx);

        if ((name->attributes & DNS_NAMEATTR_NOCOMPRESS) == 0 &&
            (methods & DNS_COMPRESS_GLOBAL14) != 0)
                gf = dns_compress_findglobal(cctx, name, &gp, &go);
        else
                gf = ISC_FALSE;

        /*
         * If the offset is too high for 14 bit global compression, we're
         * out of luck.
         */
        if (gf && go >= 0x4000)
                gf = ISC_FALSE;

        /*
         * Will the compression pointer reduce the message size?
         */
        if (gf && (gp.length + 2) >= name->length)
                gf = ISC_FALSE;

        if (gf) {
                if (target->length - target->used < gp.length)
                        return (ISC_R_NOSPACE);
                (void)memmove((unsigned char *)target->base + target->used,
                              gp.ndata, (size_t)gp.length);
                isc_buffer_add(target, gp.length);
                go |= 0xc000;
                if (target->length - target->used < 2)
                        return (ISC_R_NOSPACE);
                isc_buffer_putuint16(target, go);
                if (gp.length != 0)
                        dns_compress_add(cctx, name, &gp, offset);
        } else {
                if (target->length - target->used < name->length)
                        return (ISC_R_NOSPACE);
                (void)memmove((unsigned char *)target->base + target->used,
                              name->ndata, (size_t)name->length);
                isc_buffer_add(target, name->length);
                dns_compress_add(cctx, name, name, offset);
        }
        return (ISC_R_SUCCESS);
}

isc_result_t
dns_name_concatenate(dns_name_t *prefix, dns_name_t *suffix, dns_name_t *name,
                     isc_buffer_t *target)
{
        unsigned char *ndata, *offsets;
        unsigned int nrem, labels, prefix_length, length;
        isc_boolean_t copy_prefix = ISC_TRUE;
        isc_boolean_t copy_suffix = ISC_TRUE;
        isc_boolean_t absolute = ISC_FALSE;
        dns_name_t tmp_name;
        dns_offsets_t odata;

        /*
         * Concatenate 'prefix' and 'suffix'.
         */

        REQUIRE(prefix == NULL || VALID_NAME(prefix));
        REQUIRE(suffix == NULL || VALID_NAME(suffix));
        REQUIRE(name == NULL || VALID_NAME(name));
        REQUIRE((target != NULL && ISC_BUFFER_VALID(target)) ||
                (target == NULL && name != NULL && ISC_BUFFER_VALID(name->buffer)));
        if (prefix == NULL || prefix->labels == 0)
                copy_prefix = ISC_FALSE;
        if (suffix == NULL || suffix->labels == 0)
                copy_suffix = ISC_FALSE;
        if (copy_prefix &&
            (prefix->attributes & DNS_NAMEATTR_ABSOLUTE) != 0) {
                absolute = ISC_TRUE;
                REQUIRE(!copy_suffix);
        }
        if (name == NULL) {
                DNS_NAME_INIT(&tmp_name, odata);
                name = &tmp_name;
        }
        if (target == NULL) {
                INSIST(name->buffer != NULL);
                target = name->buffer;
                isc_buffer_clear(name->buffer);
        }

        REQUIRE(BINDABLE(name));

        /*
         * Set up.
         */
        nrem = target->length - target->used;
        ndata = (unsigned char *)target->base + target->used;
        if (nrem > DNS_NAME_MAXWIRE)
                nrem = DNS_NAME_MAXWIRE;
        length = 0;
        prefix_length = 0;
        labels = 0;
        if (copy_prefix) {
                prefix_length = prefix->length;
                length += prefix_length;
                labels += prefix->labels;
        }
        if (copy_suffix) {
                length += suffix->length;
                labels += suffix->labels;
        }
        if (length > DNS_NAME_MAXWIRE) {
                MAKE_EMPTY(name);
                return (DNS_R_NAMETOOLONG);
        }
        if (length > nrem) {
                MAKE_EMPTY(name);
                return (ISC_R_NOSPACE);
        }

        if (copy_suffix) {
                if ((suffix->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                        absolute = ISC_TRUE;
                memmove(ndata + prefix_length, suffix->ndata, suffix->length);
        }

        /*
         * If 'prefix' and 'name' are the same object, and the object has
         * a dedicated buffer, and we're using it, then we don't have to
         * copy anything.
         */
        if (copy_prefix && (prefix != name || prefix->buffer != target))
                memmove(ndata, prefix->ndata, prefix_length);

        name->ndata = ndata;
        name->labels = labels;
        name->length = length;
        if (absolute)
                name->attributes = DNS_NAMEATTR_ABSOLUTE;
        else
                name->attributes = 0;

        if (name->labels > 0 && name->offsets != NULL) {
                INIT_OFFSETS(name, offsets, odata);
                set_offsets(name, offsets, NULL);
        }

        isc_buffer_add(target, name->length);

        return (ISC_R_SUCCESS);
}

void
dns_name_split(dns_name_t *name, unsigned int suffixlabels,
               dns_name_t *prefix, dns_name_t *suffix)

{
        unsigned int splitlabel;

        REQUIRE(VALID_NAME(name));
        REQUIRE(suffixlabels > 0);
        REQUIRE(suffixlabels < name->labels);
        REQUIRE(prefix != NULL || suffix != NULL);
        REQUIRE(prefix == NULL ||
                (VALID_NAME(prefix) &&
                 prefix->buffer != NULL &&
                 BINDABLE(prefix)));
        REQUIRE(suffix == NULL ||
                (VALID_NAME(suffix) &&
                 suffix->buffer != NULL &&
                 BINDABLE(suffix)));

        splitlabel = name->labels - suffixlabels;

        if (prefix != NULL)
                dns_name_getlabelsequence(name, 0, splitlabel, prefix);

        if (suffix != NULL)
                dns_name_getlabelsequence(name, splitlabel,
                                          suffixlabels, suffix);

        return;
}

isc_result_t
dns_name_dup(const dns_name_t *source, isc_mem_t *mctx,
             dns_name_t *target)
{
        /*
         * Make 'target' a dynamically allocated copy of 'source'.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(source->length > 0);
        REQUIRE(VALID_NAME(target));
        REQUIRE(BINDABLE(target));

        /*
         * Make 'target' empty in case of failure.
         */
        MAKE_EMPTY(target);

        target->ndata = isc_mem_get(mctx, source->length);
        if (target->ndata == NULL)
                return (ISC_R_NOMEMORY);

        memmove(target->ndata, source->ndata, source->length);

        target->length = source->length;
        target->labels = source->labels;
        target->attributes = DNS_NAMEATTR_DYNAMIC;
        if ((source->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                target->attributes |= DNS_NAMEATTR_ABSOLUTE;
        if (target->offsets != NULL) {
                if (source->offsets != NULL)
                        memmove(target->offsets, source->offsets,
                                source->labels);
                else
                        set_offsets(target, target->offsets, NULL);
        }

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_name_dupwithoffsets(dns_name_t *source, isc_mem_t *mctx,
                        dns_name_t *target)
{
        /*
         * Make 'target' a read-only dynamically allocated copy of 'source'.
         * 'target' will also have a dynamically allocated offsets table.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(source->length > 0);
        REQUIRE(VALID_NAME(target));
        REQUIRE(BINDABLE(target));
        REQUIRE(target->offsets == NULL);

        /*
         * Make 'target' empty in case of failure.
         */
        MAKE_EMPTY(target);

        target->ndata = isc_mem_get(mctx, source->length + source->labels);
        if (target->ndata == NULL)
                return (ISC_R_NOMEMORY);

        memmove(target->ndata, source->ndata, source->length);

        target->length = source->length;
        target->labels = source->labels;
        target->attributes = DNS_NAMEATTR_DYNAMIC | DNS_NAMEATTR_DYNOFFSETS |
                DNS_NAMEATTR_READONLY;
        if ((source->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                target->attributes |= DNS_NAMEATTR_ABSOLUTE;
        target->offsets = target->ndata + source->length;
        if (source->offsets != NULL)
                memmove(target->offsets, source->offsets, source->labels);
        else
                set_offsets(target, target->offsets, NULL);

        return (ISC_R_SUCCESS);
}

void
dns_name_free(dns_name_t *name, isc_mem_t *mctx) {
        size_t size;

        /*
         * Free 'name'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE((name->attributes & DNS_NAMEATTR_DYNAMIC) != 0);

        size = name->length;
        if ((name->attributes & DNS_NAMEATTR_DYNOFFSETS) != 0)
                size += name->labels;
        isc_mem_put(mctx, name->ndata, size);
        dns_name_invalidate(name);
}

isc_result_t
dns_name_digest(dns_name_t *name, dns_digestfunc_t digest, void *arg) {
        dns_name_t downname;
        unsigned char data[256];
        isc_buffer_t buffer;
        isc_result_t result;
        isc_region_t r;

        /*
         * Send 'name' in DNSSEC canonical form to 'digest'.
         */

        REQUIRE(VALID_NAME(name));
        REQUIRE(digest != NULL);

#if defined(__clang__)  && \
       ( __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 2))
        memset(&downname, 0, sizeof(downname));
#endif
        DNS_NAME_INIT(&downname, NULL);

        isc_buffer_init(&buffer, data, sizeof(data));

        result = dns_name_downcase(name, &downname, &buffer);
        if (result != ISC_R_SUCCESS)
                return (result);

        isc_buffer_usedregion(&buffer, &r);

        return ((digest)(arg, &r));
}

isc_boolean_t
dns_name_dynamic(dns_name_t *name) {
        REQUIRE(VALID_NAME(name));

        /*
         * Returns whether there is dynamic memory associated with this name.
         */

        return ((name->attributes & DNS_NAMEATTR_DYNAMIC) != 0 ?
                ISC_TRUE : ISC_FALSE);
}

isc_result_t
dns_name_print(dns_name_t *name, FILE *stream) {
        isc_result_t result;
        isc_buffer_t b;
        isc_region_t r;
        char t[1024];

        /*
         * Print 'name' on 'stream'.
         */

        REQUIRE(VALID_NAME(name));

        isc_buffer_init(&b, t, sizeof(t));
        result = dns_name_totext(name, ISC_FALSE, &b);
        if (result != ISC_R_SUCCESS)
                return (result);
        isc_buffer_usedregion(&b, &r);
        fprintf(stream, "%.*s", (int)r.length, (char *)r.base);

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_name_settotextfilter(dns_name_totextfilter_t proc) {
#ifdef ISC_PLATFORM_USETHREADS
        isc_result_t result;
        dns_name_totextfilter_t *mem;
        int res;

        result = totext_filter_proc_key_init();
        if (result != ISC_R_SUCCESS)
                return (result);

        /*
         * If we already have been here set / clear as appropriate.
         * Otherwise allocate memory.
         */
        mem = isc_thread_key_getspecific(totext_filter_proc_key);
        if (mem != NULL && proc != NULL) {
                *mem = proc;
                return (ISC_R_SUCCESS);
        }
        if (proc == NULL) {
                isc_mem_put(thread_key_mctx, mem, sizeof(*mem));
                res = isc_thread_key_setspecific(totext_filter_proc_key, NULL);
                if (res != 0)
                        result = ISC_R_UNEXPECTED;
                return (result);
        }

        mem = isc_mem_get(thread_key_mctx, sizeof(*mem));
        if (mem == NULL)
                return (ISC_R_NOMEMORY);
        *mem = proc;
        if (isc_thread_key_setspecific(totext_filter_proc_key, mem) != 0) {
                isc_mem_put(thread_key_mctx, mem, sizeof(*mem));
                result = ISC_R_UNEXPECTED;
        }
        return (result);
#else
        totext_filter_proc = proc;
        return (ISC_R_SUCCESS);
#endif
}

void
dns_name_format(const dns_name_t *name, char *cp, unsigned int size) {
        isc_result_t result;
        isc_buffer_t buf;

        REQUIRE(size > 0);

        /*
         * Leave room for null termination after buffer.
         */
        isc_buffer_init(&buf, cp, size - 1);
        result = dns_name_totext(name, ISC_TRUE, &buf);
        if (result == ISC_R_SUCCESS) {
                /*
                 * Null terminate.
                 */
                isc_region_t r;
                isc_buffer_usedregion(&buf, &r);
                ((char *) r.base)[r.length] = '\0';

        } else
                snprintf(cp, size, "<unknown>");
}

/*
 * dns_name_tostring() -- similar to dns_name_format() but allocates its own
 * memory.
 */
isc_result_t
dns_name_tostring(dns_name_t *name, char **target, isc_mem_t *mctx) {
        isc_result_t result;
        isc_buffer_t buf;
        isc_region_t reg;
        char *p, txt[DNS_NAME_FORMATSIZE];

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

        isc_buffer_init(&buf, txt, sizeof(txt));
        result = dns_name_totext(name, ISC_FALSE, &buf);
        if (result != ISC_R_SUCCESS)
                return (result);

        isc_buffer_usedregion(&buf, &reg);
        p = isc_mem_allocate(mctx, reg.length + 1);
        if (p == NULL)
                return (ISC_R_NOMEMORY);
        memmove(p, (char *) reg.base, (int) reg.length);
        p[reg.length] = '\0';

        *target = p;
        return (ISC_R_SUCCESS);
}

/*
 * dns_name_fromstring() -- convert directly from a string to a name,
 * allocating memory as needed
 */
isc_result_t
dns_name_fromstring(dns_name_t *target, const char *src, unsigned int options,
                    isc_mem_t *mctx)
{
        return (dns_name_fromstring2(target, src, dns_rootname, options, mctx));
}

isc_result_t
dns_name_fromstring2(dns_name_t *target, const char *src,
                     const dns_name_t *origin, unsigned int options,
                     isc_mem_t *mctx)
{
        isc_result_t result;
        isc_buffer_t buf;
        dns_fixedname_t fn;
        dns_name_t *name;

        REQUIRE(src != NULL);

        isc_buffer_constinit(&buf, src, strlen(src));
        isc_buffer_add(&buf, strlen(src));
        if (BINDABLE(target) && target->buffer != NULL)
                name = target;
        else {
                dns_fixedname_init(&fn);
                name = dns_fixedname_name(&fn);
        }

        result = dns_name_fromtext(name, &buf, origin, options, NULL);
        if (result != ISC_R_SUCCESS)
                return (result);

        if (name != target)
                result = dns_name_dupwithoffsets(name, mctx, target);
        return (result);
}

isc_result_t
dns_name_copy(const dns_name_t *source, dns_name_t *dest, isc_buffer_t *target) {
        unsigned char *ndata;

        /*
         * Make dest a copy of source.
         */

        REQUIRE(VALID_NAME(source));
        REQUIRE(VALID_NAME(dest));
        REQUIRE(target != NULL || dest->buffer != NULL);

        if (target == NULL) {
                target = dest->buffer;
                isc_buffer_clear(dest->buffer);
        }

        REQUIRE(BINDABLE(dest));

        /*
         * Set up.
         */
        if (target->length - target->used < source->length)
                return (ISC_R_NOSPACE);

        ndata = (unsigned char *)target->base + target->used;
        dest->ndata = target->base;

        memmove(ndata, source->ndata, source->length);

        dest->ndata = ndata;
        dest->labels = source->labels;
        dest->length = source->length;
        if ((source->attributes & DNS_NAMEATTR_ABSOLUTE) != 0)
                dest->attributes = DNS_NAMEATTR_ABSOLUTE;
        else
                dest->attributes = 0;

        if (dest->labels > 0 && dest->offsets != NULL) {
                if (source->offsets != NULL)
                        memmove(dest->offsets, source->offsets, source->labels);
                else
                        set_offsets(dest, dest->offsets, NULL);
        }

        isc_buffer_add(target, dest->length);

        return (ISC_R_SUCCESS);
}

void
dns_name_destroy(void) {
#ifdef ISC_PLATFORM_USETHREADS
        RUNTIME_CHECK(isc_once_do(&once, thread_key_mutex_init)
                                  == ISC_R_SUCCESS);

        LOCK(&thread_key_mutex);
        if (thread_key_initialized) {
                isc_mem_detach(&thread_key_mctx);
                isc_thread_key_delete(totext_filter_proc_key);
                thread_key_initialized = 0;
        }
        UNLOCK(&thread_key_mutex);

#endif
}

---