/*
 * Copyright (C) 1998-2017  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id$ */

/*! \file */

#include <config.h>
#include <ctype.h>

#include <isc/base64.h>
#include <isc/hex.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/parseint.h>
#include <isc/print.h>
#include <isc/string.h>
#include <isc/stdlib.h>
#include <isc/util.h>

#include <dns/callbacks.h>
#include <dns/cert.h>
#include <dns/compress.h>
#include <dns/dsdigest.h>
#include <dns/enumtype.h>
#include <dns/keyflags.h>
#include <dns/keyvalues.h>
#include <dns/message.h>
#include <dns/rcode.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/result.h>
#include <dns/secalg.h>
#include <dns/secproto.h>
#include <dns/time.h>
#include <dns/ttl.h>

#define RETERR(x) \
	do { \
		isc_result_t _r = (x); \
		if (_r != ISC_R_SUCCESS) \
			return (_r); \
	} while (0)

#define RETTOK(x) \
	do { \
		isc_result_t _r = (x); \
		if (_r != ISC_R_SUCCESS) { \
			isc_lex_ungettoken(lexer, &token); \
			return (_r); \
		} \
	} while (0)

#define CHECK(op)						\
	do { result = (op);					\
		if (result != ISC_R_SUCCESS) goto cleanup;	\
	} while (0)

#define CHECKTOK(op)						\
	do { result = (op);					\
		if (result != ISC_R_SUCCESS) {			\
			isc_lex_ungettoken(lexer, &token);	\
			goto cleanup;				\
		}						\
	} while (0)

#define DNS_AS_STR(t) ((t).value.as_textregion.base)

#define ARGS_FROMTEXT	int rdclass, dns_rdatatype_t type, \
			isc_lex_t *lexer, dns_name_t *origin, \
			unsigned int options, isc_buffer_t *target, \
			dns_rdatacallbacks_t *callbacks

#define ARGS_TOTEXT	dns_rdata_t *rdata, dns_rdata_textctx_t *tctx, \
			isc_buffer_t *target

#define ARGS_FROMWIRE	int rdclass, dns_rdatatype_t type, \
			isc_buffer_t *source, dns_decompress_t *dctx, \
			unsigned int options, isc_buffer_t *target

#define ARGS_TOWIRE	dns_rdata_t *rdata, dns_compress_t *cctx, \
			isc_buffer_t *target

#define ARGS_COMPARE	const dns_rdata_t *rdata1, const dns_rdata_t *rdata2

#define ARGS_FROMSTRUCT	int rdclass, dns_rdatatype_t type, \
			void *source, isc_buffer_t *target

#define ARGS_TOSTRUCT	dns_rdata_t *rdata, void *target, isc_mem_t *mctx

#define ARGS_FREESTRUCT void *source

#define ARGS_ADDLDATA	dns_rdata_t *rdata, dns_additionaldatafunc_t add, \
			void *arg

#define ARGS_DIGEST	dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg

#define ARGS_CHECKOWNER dns_name_t *name, dns_rdataclass_t rdclass, \
			dns_rdatatype_t type, isc_boolean_t wildcard

#define ARGS_CHECKNAMES dns_rdata_t *rdata, dns_name_t *owner, dns_name_t *bad


/*%
 * Context structure for the totext_ functions.
 * Contains formatting options for rdata-to-text
 * conversion.
 */
typedef struct dns_rdata_textctx {
	dns_name_t *origin;	/*%< Current origin, or NULL. */
	unsigned int flags;	/*%< DNS_STYLEFLAG_*  */
	unsigned int width;	/*%< Width of rdata column. */
	const char *linebreak;	/*%< Line break string. */
} dns_rdata_textctx_t;

static isc_result_t
txt_totext(isc_region_t *source, isc_boolean_t quote, isc_buffer_t *target);

static isc_result_t
txt_fromtext(isc_textregion_t *source, isc_buffer_t *target);

static isc_result_t
txt_fromwire(isc_buffer_t *source, isc_buffer_t *target);

static isc_result_t
multitxt_totext(isc_region_t *source, isc_buffer_t *target);

static isc_result_t
multitxt_fromtext(isc_textregion_t *source, isc_buffer_t *target);

static isc_boolean_t
name_prefix(dns_name_t *name, dns_name_t *origin, dns_name_t *target);

static unsigned int
name_length(dns_name_t *name);

static isc_result_t
str_totext(const char *source, isc_buffer_t *target);

static isc_result_t
inet_totext(int af, isc_region_t *src, isc_buffer_t *target);

static isc_boolean_t
buffer_empty(isc_buffer_t *source);

static void
buffer_fromregion(isc_buffer_t *buffer, isc_region_t *region);

static isc_result_t
uint32_tobuffer(isc_uint32_t, isc_buffer_t *target);

static isc_result_t
uint16_tobuffer(isc_uint32_t, isc_buffer_t *target);

static isc_result_t
uint8_tobuffer(isc_uint32_t, isc_buffer_t *target);

static isc_result_t
name_tobuffer(dns_name_t *name, isc_buffer_t *target);

static isc_uint32_t
uint32_fromregion(isc_region_t *region);

static isc_uint16_t
uint16_fromregion(isc_region_t *region);

static isc_uint8_t
uint8_fromregion(isc_region_t *region);

static isc_uint8_t
uint8_consume_fromregion(isc_region_t *region);

static isc_result_t
mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);

static int
hexvalue(char value);

static int
decvalue(char value);

static isc_result_t
btoa_totext(unsigned char *inbuf, int inbuflen, isc_buffer_t *target);

static isc_result_t
atob_tobuffer(isc_lex_t *lexer, isc_buffer_t *target);

static void
default_fromtext_callback(dns_rdatacallbacks_t *callbacks, const char *, ...)
     ISC_FORMAT_PRINTF(2, 3);

static void
fromtext_error(void (*callback)(dns_rdatacallbacks_t *, const char *, ...),
	       dns_rdatacallbacks_t *callbacks, const char *name,
	       unsigned long line, isc_token_t *token, isc_result_t result);

static void
fromtext_warneof(isc_lex_t *lexer, dns_rdatacallbacks_t *callbacks);

static isc_result_t
rdata_totext(dns_rdata_t *rdata, dns_rdata_textctx_t *tctx,
	     isc_buffer_t *target);

static void
warn_badname(dns_name_t *name, isc_lex_t *lexer,
	     dns_rdatacallbacks_t *callbacks);

static void
warn_badmx(isc_token_t *token, isc_lex_t *lexer,
	   dns_rdatacallbacks_t *callbacks);

static isc_uint16_t
uint16_consume_fromregion(isc_region_t *region);

static isc_result_t
unknown_totext(dns_rdata_t *rdata, dns_rdata_textctx_t *tctx,
	       isc_buffer_t *target);

static inline isc_result_t
generic_fromtext_key(ARGS_FROMTEXT);

static inline isc_result_t
generic_totext_key(ARGS_TOTEXT);

static inline isc_result_t
generic_fromwire_key(ARGS_FROMWIRE);

static inline isc_result_t
generic_fromstruct_key(ARGS_FROMSTRUCT);

static inline isc_result_t
generic_tostruct_key(ARGS_TOSTRUCT);

static inline void
generic_freestruct_key(ARGS_FREESTRUCT);

static isc_result_t
generic_fromtext_txt(ARGS_FROMTEXT);

static isc_result_t
generic_totext_txt(ARGS_TOTEXT);

static isc_result_t
generic_fromwire_txt(ARGS_FROMWIRE);

static isc_result_t
generic_fromstruct_txt(ARGS_FROMSTRUCT);

static isc_result_t
generic_tostruct_txt(ARGS_TOSTRUCT);

static void
generic_freestruct_txt(ARGS_FREESTRUCT);

static isc_result_t
generic_txt_first(dns_rdata_txt_t *txt);

static isc_result_t
generic_txt_next(dns_rdata_txt_t *txt);

static isc_result_t
generic_txt_current(dns_rdata_txt_t *txt, dns_rdata_txt_string_t *string);

static isc_result_t
generic_totext_ds(ARGS_TOTEXT);

static isc_result_t
generic_tostruct_ds(ARGS_TOSTRUCT);

static isc_result_t
generic_fromtext_ds(ARGS_FROMTEXT);

static isc_result_t
generic_fromwire_ds(ARGS_FROMWIRE);

static isc_result_t
generic_fromstruct_ds(ARGS_FROMSTRUCT);

static isc_result_t
generic_fromtext_tlsa(ARGS_FROMTEXT);

static isc_result_t
generic_totext_tlsa(ARGS_TOTEXT);

static isc_result_t
generic_fromwire_tlsa(ARGS_FROMWIRE);

static isc_result_t
generic_fromstruct_tlsa(ARGS_FROMSTRUCT);

static isc_result_t
generic_tostruct_tlsa(ARGS_TOSTRUCT);

static void
generic_freestruct_tlsa(ARGS_FREESTRUCT);

/*% INT16 Size */
#define NS_INT16SZ	2
/*% IPv6 Address Size */
#define NS_LOCATORSZ	8

/*
 * Active Diretory gc._msdcs.<forest> prefix.
 */
static unsigned char gc_msdcs_data[]  = "\002gc\006_msdcs";
static unsigned char gc_msdcs_offset [] = { 0, 3 };

static dns_name_t const gc_msdcs =
	DNS_NAME_INITNONABSOLUTE(gc_msdcs_data, gc_msdcs_offset);

/*%
 *	convert presentation level address to network order binary form.
 * \return
 *	1 if `src' is a valid [RFC1884 2.2] address, else 0.
 * \note
 *	(1) does not touch `dst' unless it's returning 1.
 */
static inline int
locator_pton(const char *src, unsigned char *dst) {
	static const char xdigits_l[] = "0123456789abcdef",
			  xdigits_u[] = "0123456789ABCDEF";
	unsigned char tmp[NS_LOCATORSZ];
	unsigned char *tp = tmp, *endp;
	const char *xdigits;
	int ch, seen_xdigits;
	unsigned int val;

	memset(tp, '\0', NS_LOCATORSZ);
	endp = tp + NS_LOCATORSZ;
	seen_xdigits = 0;
	val = 0;
	while ((ch = *src++) != '\0') {
		const char *pch;

		pch = strchr((xdigits = xdigits_l), ch);
		if (pch == NULL)
			pch = strchr((xdigits = xdigits_u), ch);
		if (pch != NULL) {
			val <<= 4;
			val |= (pch - xdigits);
			if (++seen_xdigits > 4)
				return (0);
			continue;
		}
		if (ch == ':') {
			if (!seen_xdigits)
				return (0);
			if (tp + NS_INT16SZ > endp)
				return (0);
			*tp++ = (unsigned char) (val >> 8) & 0xff;
			*tp++ = (unsigned char) val & 0xff;
			seen_xdigits = 0;
			val = 0;
			continue;
		}
		return (0);
	}
	if (seen_xdigits) {
		if (tp + NS_INT16SZ > endp)
			return (0);
		*tp++ = (unsigned char) (val >> 8) & 0xff;
		*tp++ = (unsigned char) val & 0xff;
	}
	if (tp != endp)
		return (0);
	memmove(dst, tmp, NS_LOCATORSZ);
	return (1);
}

static inline int
getquad(const void *src, struct in_addr *dst,
	isc_lex_t *lexer, dns_rdatacallbacks_t *callbacks)
{
	int result;
	struct in_addr tmp;

	result = inet_aton(src, dst);
	if (result == 1 && callbacks != NULL &&
	    inet_pton(AF_INET, src, &tmp) != 1) {
		const char *name = isc_lex_getsourcename(lexer);
		if (name == NULL)
			name = "UNKNOWN";
		(*callbacks->warn)(callbacks, "%s:%lu: \"%s\" "
				   "is not a decimal dotted quad", name,
				   isc_lex_getsourceline(lexer), src);
	}
	return (result);
}

static inline isc_result_t
name_duporclone(dns_name_t *source, isc_mem_t *mctx, dns_name_t *target) {

	if (mctx != NULL)
		return (dns_name_dup(source, mctx, target));
	dns_name_clone(source, target);
	return (ISC_R_SUCCESS);
}

static inline void *
mem_maybedup(isc_mem_t *mctx, void *source, size_t length) {
	void *copy;

	if (mctx == NULL)
		return (source);
	copy = isc_mem_allocate(mctx, length);
	if (copy != NULL)
		memmove(copy, source, length);

	return (copy);
}

static inline isc_result_t
typemap_fromtext(isc_lex_t *lexer, isc_buffer_t *target,
		 isc_boolean_t allow_empty)
{
	isc_token_t token;
	unsigned char bm[8*1024]; /* 64k bits */
	dns_rdatatype_t covered, max_used;
	int octet;
	unsigned int max_octet, newend, end;
	int window;
	isc_boolean_t first = ISC_TRUE;

	max_used = 0;
	bm[0] = 0;
	end = 0;

	do {
		RETERR(isc_lex_getmastertoken(lexer, &token,
					      isc_tokentype_string, ISC_TRUE));
		if (token.type != isc_tokentype_string)
			break;
		RETTOK(dns_rdatatype_fromtext(&covered,
					      &token.value.as_textregion));
		if (covered > max_used) {
			newend = covered / 8;
			if (newend > end) {
				memset(&bm[end + 1], 0, newend - end);
				end = newend;
			}
			max_used = covered;
		}
		bm[covered/8] |= (0x80>>(covered%8));
		first = ISC_FALSE;
	} while (1);
	isc_lex_ungettoken(lexer, &token);
	if (!allow_empty && first)
		return (DNS_R_FORMERR);

	for (window = 0; window < 256 ; window++) {
		if (max_used < window * 256)
			break;

		max_octet = max_used - (window * 256);
		if (max_octet >= 256)
			max_octet = 31;
		else
			max_octet /= 8;

		/*
		 * Find if we have a type in this window.
		 */
		for (octet = max_octet; octet >= 0; octet--) {
			if (bm[window * 32 + octet] != 0)
				break;
		}
		if (octet < 0)
			continue;
		RETERR(uint8_tobuffer(window, target));
		RETERR(uint8_tobuffer(octet + 1, target));
		RETERR(mem_tobuffer(target, &bm[window * 32], octet + 1));
	}
	return (ISC_R_SUCCESS);
}

static inline isc_result_t
typemap_totext(isc_region_t *sr, dns_rdata_textctx_t *tctx,
	       isc_buffer_t *target)
{
	unsigned int i, j, k;
	unsigned int window, len;
	isc_boolean_t first = ISC_FALSE;

	for (i = 0; i < sr->length; i += len) {
		if (tctx != NULL &&
		    (tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0) {
			RETERR(str_totext(tctx->linebreak, target));
			first = ISC_TRUE;
		}
		INSIST(i + 2 <= sr->length);
		window = sr->base[i];
		len = sr->base[i + 1];
		INSIST(len > 0 && len <= 32);
		i += 2;
		INSIST(i + len <= sr->length);
		for (j = 0; j < len; j++) {
			dns_rdatatype_t t;
			if (sr->base[i + j] == 0)
				continue;
			for (k = 0; k < 8; k++) {
				if ((sr->base[i + j] & (0x80 >> k)) == 0)
					continue;
				t = window * 256 + j * 8 + k;
				if (!first)
					RETERR(str_totext(" ", target));
				first = ISC_FALSE;
				if (dns_rdatatype_isknown(t)) {
					RETERR(dns_rdatatype_totext(t, target));
				} else {
					char buf[sizeof("TYPE65535")];
					snprintf(buf, sizeof(buf), "TYPE%u", t);
					RETERR(str_totext(buf, target));
				}
			}
		}
	}
	return (ISC_R_SUCCESS);
}

static isc_result_t
typemap_test(isc_region_t *sr, isc_boolean_t allow_empty) {
	unsigned int window, lastwindow = 0;
	unsigned int len;
	isc_boolean_t first = ISC_TRUE;
	unsigned int i;

	for (i = 0; i < sr->length; i += len) {
		/*
		 * Check for overflow.
		 */
		if (i + 2 > sr->length)
			RETERR(DNS_R_FORMERR);
		window = sr->base[i];
		len = sr->base[i + 1];
		i += 2;
		/*
		 * Check that bitmap windows are in the correct order.
		 */
		if (!first && window <= lastwindow)
			RETERR(DNS_R_FORMERR);
		/*
		 * Check for legal lengths.
		 */
		if (len < 1 || len > 32)
			RETERR(DNS_R_FORMERR);
		/*
		 * Check for overflow.
		 */
		if (i + len > sr->length)
			RETERR(DNS_R_FORMERR);
		/*
		 * The last octet of the bitmap must be non zero.
		 */
		if (sr->base[i + len - 1] == 0)
			RETERR(DNS_R_FORMERR);
		lastwindow = window;
		first = ISC_FALSE;
	}
	if (i != sr->length)
		return (DNS_R_EXTRADATA);
	if (!allow_empty && first)
		RETERR(DNS_R_FORMERR);
	return (ISC_R_SUCCESS);
}

static const char hexdigits[] = "0123456789abcdef";
static const char decdigits[] = "0123456789";

#include "code.h"

#define META 0x0001
#define RESERVED 0x0002

/***
 *** Initialization
 ***/

void
dns_rdata_init(dns_rdata_t *rdata) {

	REQUIRE(rdata != NULL);

	rdata->data = NULL;
	rdata->length = 0;
	rdata->rdclass = 0;
	rdata->type = 0;
	rdata->flags = 0;
	ISC_LINK_INIT(rdata, link);
	/* ISC_LIST_INIT(rdata->list); */
}

void
dns_rdata_reset(dns_rdata_t *rdata) {

	REQUIRE(rdata != NULL);

	REQUIRE(!ISC_LINK_LINKED(rdata, link));
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

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

/***
 ***
 ***/

void
dns_rdata_clone(const dns_rdata_t *src, dns_rdata_t *target) {

	REQUIRE(src != NULL);
	REQUIRE(target != NULL);

	REQUIRE(DNS_RDATA_INITIALIZED(target));

	REQUIRE(DNS_RDATA_VALIDFLAGS(src));
	REQUIRE(DNS_RDATA_VALIDFLAGS(target));

	target->data = src->data;
	target->length = src->length;
	target->rdclass = src->rdclass;
	target->type = src->type;
	target->flags = src->flags;
}


/***
 *** Comparisons
 ***/

int
dns_rdata_compare(const dns_rdata_t *rdata1, const dns_rdata_t *rdata2) {
	int result = 0;
	isc_boolean_t use_default = ISC_FALSE;

	REQUIRE(rdata1 != NULL);
	REQUIRE(rdata2 != NULL);
	REQUIRE(rdata1->length == 0 || rdata1->data != NULL);
	REQUIRE(rdata2->length == 0 || rdata2->data != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata1));
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata2));

	if (rdata1->rdclass != rdata2->rdclass)
		return (rdata1->rdclass < rdata2->rdclass ? -1 : 1);

	if (rdata1->type != rdata2->type)
		return (rdata1->type < rdata2->type ? -1 : 1);

	COMPARESWITCH

	if (use_default) {
		isc_region_t r1;
		isc_region_t r2;

		dns_rdata_toregion(rdata1, &r1);
		dns_rdata_toregion(rdata2, &r2);
		result = isc_region_compare(&r1, &r2);
	}
	return (result);
}

int
dns_rdata_casecompare(const dns_rdata_t *rdata1, const dns_rdata_t *rdata2) {
	int result = 0;
	isc_boolean_t use_default = ISC_FALSE;

	REQUIRE(rdata1 != NULL);
	REQUIRE(rdata2 != NULL);
	REQUIRE(rdata1->length == 0 || rdata1->data != NULL);
	REQUIRE(rdata2->length == 0 || rdata2->data != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata1));
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata2));

	if (rdata1->rdclass != rdata2->rdclass)
		return (rdata1->rdclass < rdata2->rdclass ? -1 : 1);

	if (rdata1->type != rdata2->type)
		return (rdata1->type < rdata2->type ? -1 : 1);

	CASECOMPARESWITCH

	if (use_default) {
		isc_region_t r1;
		isc_region_t r2;

		dns_rdata_toregion(rdata1, &r1);
		dns_rdata_toregion(rdata2, &r2);
		result = isc_region_compare(&r1, &r2);
	}
	return (result);
}

/***
 *** Conversions
 ***/

void
dns_rdata_fromregion(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
		     dns_rdatatype_t type, isc_region_t *r)
{

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_INITIALIZED(rdata));
	REQUIRE(r != NULL);

	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	rdata->data = r->base;
	rdata->length = r->length;
	rdata->rdclass = rdclass;
	rdata->type = type;
	rdata->flags = 0;
}

void
dns_rdata_toregion(const dns_rdata_t *rdata, isc_region_t *r) {

	REQUIRE(rdata != NULL);
	REQUIRE(r != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	r->base = rdata->data;
	r->length = rdata->length;
}

isc_result_t
dns_rdata_fromwire(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
		   dns_rdatatype_t type, isc_buffer_t *source,
		   dns_decompress_t *dctx, unsigned int options,
		   isc_buffer_t *target)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_region_t region;
	isc_buffer_t ss;
	isc_buffer_t st;
	isc_boolean_t use_default = ISC_FALSE;
	isc_uint32_t activelength;
	unsigned int length;

	REQUIRE(dctx != NULL);
	if (rdata != NULL) {
		REQUIRE(DNS_RDATA_INITIALIZED(rdata));
		REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));
	}
	REQUIRE(source != NULL);
	REQUIRE(target != NULL);

	if (type == 0)
		return (DNS_R_FORMERR);

	ss = *source;
	st = *target;

	activelength = isc_buffer_activelength(source);
	INSIST(activelength < 65536);

	FROMWIRESWITCH

	if (use_default) {
		if (activelength > isc_buffer_availablelength(target))
			result = ISC_R_NOSPACE;
		else {
			isc_buffer_putmem(target, isc_buffer_current(source),
					  activelength);
			isc_buffer_forward(source, activelength);
			result = ISC_R_SUCCESS;
		}
	}

	/*
	 * Reject any rdata that expands out to more than DNS_RDATA_MAXLENGTH
	 * as we cannot transmit it.
	 */
	length = isc_buffer_usedlength(target) - isc_buffer_usedlength(&st);
	if (result == ISC_R_SUCCESS && length > DNS_RDATA_MAXLENGTH)
		result = DNS_R_FORMERR;

	/*
	 * We should have consumed all of our buffer.
	 */
	if (result == ISC_R_SUCCESS && !buffer_empty(source))
		result = DNS_R_EXTRADATA;

	if (rdata != NULL && result == ISC_R_SUCCESS) {
		region.base = isc_buffer_used(&st);
		region.length = length;
		dns_rdata_fromregion(rdata, rdclass, type, &region);
	}

	if (result != ISC_R_SUCCESS) {
		*source = ss;
		*target = st;
	}
	return (result);
}

isc_result_t
dns_rdata_towire(dns_rdata_t *rdata, dns_compress_t *cctx,
		 isc_buffer_t *target)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_boolean_t use_default = ISC_FALSE;
	isc_region_t tr;
	isc_buffer_t st;

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	/*
	 * Some DynDNS meta-RRs have empty rdata.
	 */
	if ((rdata->flags & DNS_RDATA_UPDATE) != 0) {
		INSIST(rdata->length == 0);
		return (ISC_R_SUCCESS);
	}

	st = *target;

	TOWIRESWITCH

	if (use_default) {
		isc_buffer_availableregion(target, &tr);
		if (tr.length < rdata->length)
			return (ISC_R_NOSPACE);
		memmove(tr.base, rdata->data, rdata->length);
		isc_buffer_add(target, rdata->length);
		return (ISC_R_SUCCESS);
	}
	if (result != ISC_R_SUCCESS) {
		*target = st;
		INSIST(target->used < 65536);
		dns_compress_rollback(cctx, (isc_uint16_t)target->used);
	}
	return (result);
}

/*
 * If the binary data in 'src' is valid uncompressed wire format
 * rdata of class 'rdclass' and type 'type', return ISC_R_SUCCESS
 * and copy the validated rdata to 'dest'.  Otherwise return an error.
 */
static isc_result_t
rdata_validate(isc_buffer_t *src, isc_buffer_t *dest, dns_rdataclass_t rdclass,
	    dns_rdatatype_t type)
{
	dns_decompress_t dctx;
	isc_result_t result;

	dns_decompress_init(&dctx, -1, DNS_DECOMPRESS_NONE);
	isc_buffer_setactive(src, isc_buffer_usedlength(src));
	result = dns_rdata_fromwire(NULL, rdclass, type, src, &dctx, 0, dest);
	dns_decompress_invalidate(&dctx);

	return (result);
}

static isc_result_t
unknown_fromtext(dns_rdataclass_t rdclass, dns_rdatatype_t type,
		 isc_lex_t *lexer, isc_mem_t *mctx, isc_buffer_t *target)
{
	isc_result_t result;
	isc_buffer_t *buf = NULL;
	isc_token_t token;

	if (type == 0 || dns_rdatatype_ismeta(type))
		return (DNS_R_METATYPE);

	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_number,
					ISC_FALSE));
	if (token.value.as_ulong > 65535U)
		return (ISC_R_RANGE);
	result = isc_buffer_allocate(mctx, &buf, token.value.as_ulong);
	if (result != ISC_R_SUCCESS)
		return (result);

	result = isc_hex_tobuffer(lexer, buf,
				  (unsigned int)token.value.as_ulong);
	if (result != ISC_R_SUCCESS)
	       goto failure;
	if (isc_buffer_usedlength(buf) != token.value.as_ulong) {
		result = ISC_R_UNEXPECTEDEND;
		goto failure;
	}

	if (dns_rdatatype_isknown(type)) {
		result = rdata_validate(buf, target, rdclass, type);
	} else {
		isc_region_t r;
		isc_buffer_usedregion(buf, &r);
		result = isc_buffer_copyregion(target, &r);
	}
	if (result != ISC_R_SUCCESS)
		goto failure;

	isc_buffer_free(&buf);
	return (ISC_R_SUCCESS);

 failure:
	isc_buffer_free(&buf);
	return (result);
}

isc_result_t
dns_rdata_fromtext(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
		   dns_rdatatype_t type, isc_lex_t *lexer,
		   dns_name_t *origin, unsigned int options, isc_mem_t *mctx,
		   isc_buffer_t *target, dns_rdatacallbacks_t *callbacks)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_region_t region;
	isc_buffer_t st;
	isc_token_t token;
	unsigned int lexoptions = ISC_LEXOPT_EOL | ISC_LEXOPT_EOF |
				  ISC_LEXOPT_DNSMULTILINE | ISC_LEXOPT_ESCAPE;
	char *name;
	unsigned long line;
	void (*callback)(dns_rdatacallbacks_t *, const char *, ...);
	isc_result_t tresult;
	unsigned int length;
	isc_boolean_t unknown;

	REQUIRE(origin == NULL || dns_name_isabsolute(origin) == ISC_TRUE);
	if (rdata != NULL) {
		REQUIRE(DNS_RDATA_INITIALIZED(rdata));
		REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));
	}
	if (callbacks != NULL) {
		REQUIRE(callbacks->warn != NULL);
		REQUIRE(callbacks->error != NULL);
	}

	st = *target;

	if (callbacks != NULL)
		callback = callbacks->error;
	else
		callback = default_fromtext_callback;

	result = isc_lex_getmastertoken(lexer, &token, isc_tokentype_qstring,
					ISC_FALSE);
	if (result != ISC_R_SUCCESS) {
		name = isc_lex_getsourcename(lexer);
		line = isc_lex_getsourceline(lexer);
		fromtext_error(callback, callbacks, name, line, NULL, result);
		return (result);
	}

	unknown = ISC_FALSE;
	if (token.type == isc_tokentype_string &&
	    strcmp(DNS_AS_STR(token), "\\#") == 0) {
		/*
		 * If this is a TXT record '\#' could be a escaped '#'.
		 * Look to see if the next token is a number and if so
		 * treat it as a unknown record format.
		 */
		if (type == dns_rdatatype_txt) {
			result = isc_lex_getmastertoken(lexer, &token,
							isc_tokentype_number,
							ISC_FALSE);
			if (result == ISC_R_SUCCESS)
				isc_lex_ungettoken(lexer, &token);
		}

		if (result == ISC_R_SUCCESS) {
			unknown = ISC_TRUE;
			result = unknown_fromtext(rdclass, type, lexer,
						  mctx, target);
		} else
			options |= DNS_RDATA_UNKNOWNESCAPE;
	} else
		isc_lex_ungettoken(lexer, &token);

	if (!unknown)
		FROMTEXTSWITCH

	/*
	 * Consume to end of line / file.
	 * If not at end of line initially set error code.
	 * Call callback via fromtext_error once if there was an error.
	 */
	do {
		name = isc_lex_getsourcename(lexer);
		line = isc_lex_getsourceline(lexer);
		tresult = isc_lex_gettoken(lexer, lexoptions, &token);
		if (tresult != ISC_R_SUCCESS) {
			if (result == ISC_R_SUCCESS)
				result = tresult;
			if (callback != NULL)
				fromtext_error(callback, callbacks, name,
					       line, NULL, result);
			break;
		} else if (token.type != isc_tokentype_eol &&
			   token.type != isc_tokentype_eof) {
			if (result == ISC_R_SUCCESS)
				result = DNS_R_EXTRATOKEN;
			if (callback != NULL) {
				fromtext_error(callback, callbacks, name,
					       line, &token, result);
				callback = NULL;
			}
		} else if (result != ISC_R_SUCCESS && callback != NULL) {
			fromtext_error(callback, callbacks, name, line,
				       &token, result);
			break;
		} else {
			if (token.type == isc_tokentype_eof)
				fromtext_warneof(lexer, callbacks);
			break;
		}
	} while (1);

	length = isc_buffer_usedlength(target) - isc_buffer_usedlength(&st);
	if (result == ISC_R_SUCCESS && length > DNS_RDATA_MAXLENGTH)
		result = ISC_R_NOSPACE;

	if (rdata != NULL && result == ISC_R_SUCCESS) {
		region.base = isc_buffer_used(&st);
		region.length = length;
		dns_rdata_fromregion(rdata, rdclass, type, &region);
	}
	if (result != ISC_R_SUCCESS) {
		*target = st;
	}
	return (result);
}

static isc_result_t
unknown_totext(dns_rdata_t *rdata, dns_rdata_textctx_t *tctx,
	       isc_buffer_t *target)
{
	isc_result_t result;
	char buf[sizeof("65535")];
	isc_region_t sr;

	strlcpy(buf, "\\# ", sizeof(buf));
	result = str_totext(buf, target);
	if (result != ISC_R_SUCCESS)
		return (result);

	dns_rdata_toregion(rdata, &sr);
	INSIST(sr.length < 65536);
	snprintf(buf, sizeof(buf), "%u", sr.length);
	result = str_totext(buf, target);
	if (result != ISC_R_SUCCESS)
		return (result);

	if (sr.length != 0U) {
		if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0)
			result = str_totext(" ( ", target);
		else
			result = str_totext(" ", target);

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

		if (tctx->width == 0) /* No splitting */
			result = isc_hex_totext(&sr, 0, "", target);
		else
			result = isc_hex_totext(&sr, tctx->width - 2,
						tctx->linebreak,
						target);
		if (result == ISC_R_SUCCESS &&
		    (tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0)
			result = str_totext(" )", target);
	}
	return (result);
}

static isc_result_t
rdata_totext(dns_rdata_t *rdata, dns_rdata_textctx_t *tctx,
	     isc_buffer_t *target)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_boolean_t use_default = ISC_FALSE;
	unsigned int cur;

	REQUIRE(rdata != NULL);
	REQUIRE(tctx->origin == NULL ||
		dns_name_isabsolute(tctx->origin) == ISC_TRUE);

	/*
	 * Some DynDNS meta-RRs have empty rdata.
	 */
	if ((rdata->flags & DNS_RDATA_UPDATE) != 0) {
		INSIST(rdata->length == 0);
		return (ISC_R_SUCCESS);
	}

	if ((tctx->flags & DNS_STYLEFLAG_UNKNOWNFORMAT) != 0)
		return (unknown_totext(rdata, tctx, target));

	cur = isc_buffer_usedlength(target);

	TOTEXTSWITCH

	if (use_default || (result == ISC_R_NOTIMPLEMENTED)) {
		unsigned int u = isc_buffer_usedlength(target);

		INSIST(u >= cur);
		isc_buffer_subtract(target, u - cur);
		result = unknown_totext(rdata, tctx, target);
	}

	return (result);
}

isc_result_t
dns_rdata_totext(dns_rdata_t *rdata, dns_name_t *origin, isc_buffer_t *target)
{
	dns_rdata_textctx_t tctx;

	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	/*
	 * Set up formatting options for single-line output.
	 */
	tctx.origin = origin;
	tctx.flags = 0;
	tctx.width = 60;
	tctx.linebreak = " ";
	return (rdata_totext(rdata, &tctx, target));
}

isc_result_t
dns_rdata_tofmttext(dns_rdata_t *rdata, dns_name_t *origin,
		    unsigned int flags, unsigned int width,
		    unsigned int split_width, const char *linebreak,
		    isc_buffer_t *target)
{
	dns_rdata_textctx_t tctx;

	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	/*
	 * Set up formatting options for formatted output.
	 */
	tctx.origin = origin;
	tctx.flags = flags;
	if (split_width == 0xffffffff)
		tctx.width = width;
	else
		tctx.width = split_width;

	if ((flags & DNS_STYLEFLAG_MULTILINE) != 0)
		tctx.linebreak = linebreak;
	else {
		if (split_width == 0xffffffff)
			tctx.width = 60; /* Used for hex word length only. */
		tctx.linebreak = " ";
	}
	return (rdata_totext(rdata, &tctx, target));
}

isc_result_t
dns_rdata_fromstruct(dns_rdata_t *rdata, dns_rdataclass_t rdclass,
		     dns_rdatatype_t type, void *source,
		     isc_buffer_t *target)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_buffer_t st;
	isc_region_t region;
	isc_boolean_t use_default = ISC_FALSE;
	unsigned int length;

	REQUIRE(source != NULL);
	if (rdata != NULL) {
		REQUIRE(DNS_RDATA_INITIALIZED(rdata));
		REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));
	}

	st = *target;

	FROMSTRUCTSWITCH

	if (use_default)
		(void)NULL;

	length = isc_buffer_usedlength(target) - isc_buffer_usedlength(&st);
	if (result == ISC_R_SUCCESS && length > DNS_RDATA_MAXLENGTH)
		result = ISC_R_NOSPACE;

	if (rdata != NULL && result == ISC_R_SUCCESS) {
		region.base = isc_buffer_used(&st);
		region.length = length;
		dns_rdata_fromregion(rdata, rdclass, type, &region);
	}
	if (result != ISC_R_SUCCESS)
		*target = st;
	return (result);
}

isc_result_t
dns_rdata_tostruct(dns_rdata_t *rdata, void *target, isc_mem_t *mctx) {
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_boolean_t use_default = ISC_FALSE;

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	TOSTRUCTSWITCH

	if (use_default)
		(void)NULL;

	return (result);
}

void
dns_rdata_freestruct(void *source) {
	dns_rdatacommon_t *common = source;
	REQUIRE(source != NULL);

	FREESTRUCTSWITCH
}

isc_result_t
dns_rdata_additionaldata(dns_rdata_t *rdata, dns_additionaldatafunc_t add,
			 void *arg)
{
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_boolean_t use_default = ISC_FALSE;

	/*
	 * Call 'add' for each name and type from 'rdata' which is subject to
	 * additional section processing.
	 */

	REQUIRE(rdata != NULL);
	REQUIRE(add != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	ADDITIONALDATASWITCH

	/* No additional processing for unknown types */
	if (use_default)
		result = ISC_R_SUCCESS;

	return (result);
}

isc_result_t
dns_rdata_digest(dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg) {
	isc_result_t result = ISC_R_NOTIMPLEMENTED;
	isc_boolean_t use_default = ISC_FALSE;
	isc_region_t r;

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

	REQUIRE(rdata != NULL);
	REQUIRE(digest != NULL);
	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));

	DIGESTSWITCH

	if (use_default) {
		dns_rdata_toregion(rdata, &r);
		result = (digest)(arg, &r);
	}

	return (result);
}

isc_boolean_t
dns_rdata_checkowner(dns_name_t *name, dns_rdataclass_t rdclass,
		     dns_rdatatype_t type, isc_boolean_t wildcard)
{
	isc_boolean_t result;

	CHECKOWNERSWITCH
	return (result);
}

isc_boolean_t
dns_rdata_checknames(dns_rdata_t *rdata, dns_name_t *owner, dns_name_t *bad)
{
	isc_boolean_t result;

	CHECKNAMESSWITCH
	return (result);
}

unsigned int
dns_rdatatype_attributes(dns_rdatatype_t type)
{
	RDATATYPE_ATTRIBUTE_SW
	if (type >= (dns_rdatatype_t)128 && type < (dns_rdatatype_t)255)
		return (DNS_RDATATYPEATTR_UNKNOWN | DNS_RDATATYPEATTR_META);
	return (DNS_RDATATYPEATTR_UNKNOWN);
}

isc_result_t
dns_rdatatype_fromtext(dns_rdatatype_t *typep, isc_textregion_t *source) {
	unsigned int hash;
	unsigned int n;
	unsigned char a, b;

	n = source->length;

	if (n == 0)
		return (DNS_R_UNKNOWN);

	a = tolower((unsigned char)source->base[0]);
	b = tolower((unsigned char)source->base[n - 1]);

	hash = ((a + n) * b) % 256;

	/*
	 * This switch block is inlined via \#define, and will use "return"
	 * to return a result to the caller if it is a valid (known)
	 * rdatatype name.
	 */
	RDATATYPE_FROMTEXT_SW(hash, source->base, n, typep);

	if (source->length > 4 && source->length < (4 + sizeof("65000")) &&
	    strncasecmp("type", source->base, 4) == 0) {
		char buf[sizeof("65000")];
		char *endp;
		unsigned int val;

		/*
		 * source->base is not required to be NUL terminated.
		 * Copy up to remaining bytes and NUL terminate.
		 */
		snprintf(buf, sizeof(buf), "%.*s",
			 (int)(source->length - 4), source->base + 4);
		val = strtoul(buf, &endp, 10);
		if (*endp == '\0' && val <= 0xffff) {
			*typep = (dns_rdatatype_t)val;
			return (ISC_R_SUCCESS);
		}
	}

	return (DNS_R_UNKNOWN);
}

isc_result_t
dns_rdatatype_totext(dns_rdatatype_t type, isc_buffer_t *target) {
	RDATATYPE_TOTEXT_SW

	return (dns_rdatatype_tounknowntext(type, target));
}

isc_result_t
dns_rdatatype_tounknowntext(dns_rdatatype_t type, isc_buffer_t *target) {
	char buf[sizeof("TYPE65535")];

	snprintf(buf, sizeof(buf), "TYPE%u", type);
	return (str_totext(buf, target));
}

void
dns_rdatatype_format(dns_rdatatype_t rdtype,
		     char *array, unsigned int size)
{
	isc_result_t result;
	isc_buffer_t buf;

	if (size == 0U)
		return;

	isc_buffer_init(&buf, array, size);
	result = dns_rdatatype_totext(rdtype, &buf);
	/*
	 * Null terminate.
	 */
	if (result == ISC_R_SUCCESS) {
		if (isc_buffer_availablelength(&buf) >= 1)
			isc_buffer_putuint8(&buf, 0);
		else
			result = ISC_R_NOSPACE;
	}
	if (result != ISC_R_SUCCESS)
		strlcpy(array, "<unknown>", size);
}

/*
 * Private function.
 */

static unsigned int
name_length(dns_name_t *name) {
	return (name->length);
}

static isc_result_t
txt_totext(isc_region_t *source, isc_boolean_t quote, isc_buffer_t *target) {
	unsigned int tl;
	unsigned int n;
	unsigned char *sp;
	char *tp;
	isc_region_t region;

	isc_buffer_availableregion(target, &region);
	sp = source->base;
	tp = (char *)region.base;
	tl = region.length;

	n = *sp++;

	REQUIRE(n + 1 <= source->length);
	if (n == 0U)
		REQUIRE(quote == ISC_TRUE);

	if (quote) {
		if (tl < 1)
			return (ISC_R_NOSPACE);
		*tp++ = '"';
		tl--;
	}
	while (n--) {
		/*
		 * \DDD space (0x20) if not quoting.
		 */
		if (*sp < (quote ? 0x20 : 0x21) || *sp >= 0x7f) {
			if (tl < 4)
				return (ISC_R_NOSPACE);
			*tp++ = 0x5c;
			*tp++ = 0x30 + ((*sp / 100) % 10);
			*tp++ = 0x30 + ((*sp / 10) % 10);
			*tp++ = 0x30 + (*sp % 10);
			sp++;
			tl -= 4;
			continue;
		}
		/*
		 * Escape double quote and backslash.  If we are not
		 * enclosing the string in double quotes also escape
		 * at sign and semicolon.
		 */
		if (*sp == 0x22 || *sp == 0x5c ||
		    (!quote && (*sp == 0x40 || *sp == 0x3b))) {
			if (tl < 2)
				return (ISC_R_NOSPACE);
			*tp++ = '\\';
			tl--;
		}
		if (tl < 1)
			return (ISC_R_NOSPACE);
		*tp++ = *sp++;
		tl--;
	}
	if (quote) {
		if (tl < 1)
			return (ISC_R_NOSPACE);
		*tp++ = '"';
		tl--;
	}
	isc_buffer_add(target, (unsigned int)(tp - (char *)region.base));
	isc_region_consume(source, *source->base + 1);
	return (ISC_R_SUCCESS);
}

static isc_result_t
txt_fromtext(isc_textregion_t *source, isc_buffer_t *target) {
	isc_region_t tregion;
	isc_boolean_t escape;
	unsigned int n, nrem;
	char *s;
	unsigned char *t;
	int d;
	int c;

	isc_buffer_availableregion(target, &tregion);
	s = source->base;
	n = source->length;
	t = tregion.base;
	nrem = tregion.length;
	escape = ISC_FALSE;
	if (nrem < 1)
		return (ISC_R_NOSPACE);
	/*
	 * Length byte.
	 */
	nrem--;
	t++;
	/*
	 * Maximum text string length.
	 */
	if (nrem > 255)
		nrem = 255;
	while (n-- != 0) {
		c = (*s++) & 0xff;
		if (escape && (d = decvalue((char)c)) != -1) {
			c = d;
			if (n == 0)
				return (DNS_R_SYNTAX);
			n--;
			if ((d = decvalue(*s++)) != -1)
				c = c * 10 + d;
			else
				return (DNS_R_SYNTAX);
			if (n == 0)
				return (DNS_R_SYNTAX);
			n--;
			if ((d = decvalue(*s++)) != -1)
				c = c * 10 + d;
			else
				return (DNS_R_SYNTAX);
			if (c > 255)
				return (DNS_R_SYNTAX);
		} else if (!escape && c == '\\') {
			escape = ISC_TRUE;
			continue;
		}
		escape = ISC_FALSE;
		if (nrem == 0)
			return ((tregion.length <= 256U) ?
				ISC_R_NOSPACE : DNS_R_SYNTAX);
		*t++ = c;
		nrem--;
	}
	if (escape)
		return (DNS_R_SYNTAX);
	*tregion.base = (unsigned char)(t - tregion.base - 1);
	isc_buffer_add(target, *tregion.base + 1);
	return (ISC_R_SUCCESS);
}

static isc_result_t
txt_fromwire(isc_buffer_t *source, isc_buffer_t *target) {
	unsigned int n;
	isc_region_t sregion;
	isc_region_t tregion;

	isc_buffer_activeregion(source, &sregion);
	if (sregion.length == 0)
		return (ISC_R_UNEXPECTEDEND);
	n = *sregion.base + 1;
	if (n > sregion.length)
		return (ISC_R_UNEXPECTEDEND);

	isc_buffer_availableregion(target, &tregion);
	if (n > tregion.length)
		return (ISC_R_NOSPACE);

	if (tregion.base != sregion.base)
		memmove(tregion.base, sregion.base, n);
	isc_buffer_forward(source, n);
	isc_buffer_add(target, n);
	return (ISC_R_SUCCESS);
}

/*
 * Conversion of TXT-like rdata fields without length limits.
 */
static isc_result_t
multitxt_totext(isc_region_t *source, isc_buffer_t *target) {
	unsigned int tl;
	unsigned int n0, n;
	unsigned char *sp;
	char *tp;
	isc_region_t region;

	isc_buffer_availableregion(target, &region);
	sp = source->base;
	tp = (char *)region.base;
	tl = region.length;

	if (tl < 1)
		return (ISC_R_NOSPACE);
	*tp++ = '"';
	tl--;
	do {
		n = source->length;
		n0 = source->length - 1;

		while (n--) {
			if (*sp < 0x20 || *sp >= 0x7f) {
				if (tl < 4)
					return (ISC_R_NOSPACE);
				*tp++ = 0x5c;
				*tp++ = 0x30 + ((*sp / 100) % 10);
				*tp++ = 0x30 + ((*sp / 10) % 10);
				*tp++ = 0x30 + (*sp % 10);
				sp++;
				tl -= 4;
				continue;
			}
			/* double quote, backslash */
			if (*sp == 0x22 || *sp == 0x5c) {
				if (tl < 2)
					return (ISC_R_NOSPACE);
				*tp++ = '\\';
				tl--;
			}
			if (tl < 1)
				return (ISC_R_NOSPACE);
			*tp++ = *sp++;
			tl--;
		}
		isc_region_consume(source, n0 + 1);
	} while (source->length != 0);
	if (tl < 1)
		return (ISC_R_NOSPACE);
	*tp++ = '"';
	tl--;
	isc_buffer_add(target, (unsigned int)(tp - (char *)region.base));
	return (ISC_R_SUCCESS);
}

static isc_result_t
multitxt_fromtext(isc_textregion_t *source, isc_buffer_t *target) {
	isc_region_t tregion;
	isc_boolean_t escape;
	unsigned int n, nrem;
	char *s;
	unsigned char *t0, *t;
	int d;
	int c;

	s = source->base;
	n = source->length;
	escape = ISC_FALSE;

	do {
		isc_buffer_availableregion(target, &tregion);
		t0 = t = tregion.base;
		nrem = tregion.length;
		if (nrem < 1)
			return (ISC_R_NOSPACE);

		while (n != 0) {
			--n;
			c = (*s++) & 0xff;
			if (escape && (d = decvalue((char)c)) != -1) {
				c = d;
				if (n == 0)
					return (DNS_R_SYNTAX);
				n--;
				if ((d = decvalue(*s++)) != -1)
					c = c * 10 + d;
				else
					return (DNS_R_SYNTAX);
				if (n == 0)
					return (DNS_R_SYNTAX);
				n--;
				if ((d = decvalue(*s++)) != -1)
					c = c * 10 + d;
				else
					return (DNS_R_SYNTAX);
				if (c > 255)
					return (DNS_R_SYNTAX);
			} else if (!escape && c == '\\') {
				escape = ISC_TRUE;
				continue;
			}
			escape = ISC_FALSE;
			*t++ = c;
			nrem--;
			if (nrem == 0)
				break;
		}
		if (escape)
			return (DNS_R_SYNTAX);

		isc_buffer_add(target, (unsigned int)(t - t0));
	} while (n != 0);
	return (ISC_R_SUCCESS);
}

static isc_boolean_t
name_prefix(dns_name_t *name, dns_name_t *origin, dns_name_t *target) {
	int l1, l2;

	if (origin == NULL)
		goto return_false;

	if (dns_name_compare(origin, dns_rootname) == 0)
		goto return_false;

	if (!dns_name_issubdomain(name, origin))
		goto return_false;

	l1 = dns_name_countlabels(name);
	l2 = dns_name_countlabels(origin);

	if (l1 == l2)
		goto return_false;

	/* Master files should be case preserving. */
	dns_name_getlabelsequence(name, l1 - l2, l2, target);
	if (!dns_name_caseequal(origin, target))
		goto return_false;

	dns_name_getlabelsequence(name, 0, l1 - l2, target);
	return (ISC_TRUE);

return_false:
	*target = *name;
	return (ISC_FALSE);
}

static isc_result_t
str_totext(const char *source, isc_buffer_t *target) {
	unsigned int l;
	isc_region_t region;

	isc_buffer_availableregion(target, &region);
	l = strlen(source);

	if (l > region.length)
		return (ISC_R_NOSPACE);

	memmove(region.base, source, l);
	isc_buffer_add(target, l);
	return (ISC_R_SUCCESS);
}

static isc_result_t
inet_totext(int af, isc_region_t *src, isc_buffer_t *target) {
	char tmpbuf[64];

	/* Note - inet_ntop doesn't do size checking on its input. */
	if (inet_ntop(af, src->base, tmpbuf, sizeof(tmpbuf)) == NULL)
		return (ISC_R_NOSPACE);
	if (strlen(tmpbuf) > isc_buffer_availablelength(target))
		return (ISC_R_NOSPACE);
	isc_buffer_putstr(target, tmpbuf);
	return (ISC_R_SUCCESS);
}

static isc_boolean_t
buffer_empty(isc_buffer_t *source) {
	return((source->current == source->active) ? ISC_TRUE : ISC_FALSE);
}

static void
buffer_fromregion(isc_buffer_t *buffer, isc_region_t *region) {
	isc_buffer_init(buffer, region->base, region->length);
	isc_buffer_add(buffer, region->length);
	isc_buffer_setactive(buffer, region->length);
}

static isc_result_t
uint32_tobuffer(isc_uint32_t value, isc_buffer_t *target) {
	isc_region_t region;

	isc_buffer_availableregion(target, &region);
	if (region.length < 4)
		return (ISC_R_NOSPACE);
	isc_buffer_putuint32(target, value);
	return (ISC_R_SUCCESS);
}

static isc_result_t
uint16_tobuffer(isc_uint32_t value, isc_buffer_t *target) {
	isc_region_t region;

	if (value > 0xffff)
		return (ISC_R_RANGE);
	isc_buffer_availableregion(target, &region);
	if (region.length < 2)
		return (ISC_R_NOSPACE);
	isc_buffer_putuint16(target, (isc_uint16_t)value);
	return (ISC_R_SUCCESS);
}

static isc_result_t
uint8_tobuffer(isc_uint32_t value, isc_buffer_t *target) {
	isc_region_t region;

	if (value > 0xff)
		return (ISC_R_RANGE);
	isc_buffer_availableregion(target, &region);
	if (region.length < 1)
		return (ISC_R_NOSPACE);
	isc_buffer_putuint8(target, (isc_uint8_t)value);
	return (ISC_R_SUCCESS);
}

static isc_result_t
name_tobuffer(dns_name_t *name, isc_buffer_t *target) {
	isc_region_t r;
	dns_name_toregion(name, &r);
	return (isc_buffer_copyregion(target, &r));
}

static isc_uint32_t
uint32_fromregion(isc_region_t *region) {
	isc_uint32_t value;

	REQUIRE(region->length >= 4);
	value = (isc_uint32_t)region->base[0] << 24;
	value |= (isc_uint32_t)region->base[1] << 16;
	value |= (isc_uint32_t)region->base[2] << 8;
	value |= (isc_uint32_t)region->base[3];
	return(value);
}

static isc_uint16_t
uint16_consume_fromregion(isc_region_t *region) {
	isc_uint16_t r = uint16_fromregion(region);

	isc_region_consume(region, 2);
	return r;
}

static isc_uint16_t
uint16_fromregion(isc_region_t *region) {

	REQUIRE(region->length >= 2);

	return ((region->base[0] << 8) | region->base[1]);
}

static isc_uint8_t
uint8_fromregion(isc_region_t *region) {

	REQUIRE(region->length >= 1);

	return (region->base[0]);
}

static isc_uint8_t
uint8_consume_fromregion(isc_region_t *region) {
	isc_uint8_t r = uint8_fromregion(region);

	isc_region_consume(region, 1);
	return r;
}

static isc_result_t
mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
	isc_region_t tr;

	if (length == 0U)
		return (ISC_R_SUCCESS);

	isc_buffer_availableregion(target, &tr);
	if (length > tr.length)
		return (ISC_R_NOSPACE);
	if (tr.base != base)
		memmove(tr.base, base, length);
	isc_buffer_add(target, length);
	return (ISC_R_SUCCESS);
}

static int
hexvalue(char value) {
	const char *s;
	unsigned char c;

	c = (unsigned char)value;

	if (!isascii(c))
		return (-1);
	if (isupper(c))
		c = tolower(c);
	if ((s = strchr(hexdigits, c)) == NULL)
		return (-1);
	return (int)(s - hexdigits);
}

static int
decvalue(char value) {
	const char *s;

	/*
	 * isascii() is valid for full range of int values, no need to
	 * mask or cast.
	 */
	if (!isascii(value))
		return (-1);
	if ((s = strchr(decdigits, value)) == NULL)
		return (-1);
	return (int)(s - decdigits);
}

static const char atob_digits[86] =
	"!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`" \
	"abcdefghijklmnopqrstu";
/*
 * Subroutines to convert between 8 bit binary bytes and printable ASCII.
 * Computes the number of bytes, and three kinds of simple checksums.
 * Incoming bytes are collected into 32-bit words, then printed in base 85:
 *	exp(85,5) > exp(2,32)
 * The ASCII characters used are between '!' and 'u';
 * 'z' encodes 32-bit zero; 'x' is used to mark the end of encoded data.
 *
 * Originally by Paul Rutter (philabs!per) and Joe Orost (petsd!joe) for
 * the atob/btoa programs, released with the compress program, in mod.sources.
 * Modified by Mike Schwartz 8/19/86 for use in BIND.
 * Modified to be re-entrant 3/2/99.
 */


struct state {
	isc_int32_t Ceor;
	isc_int32_t Csum;
	isc_int32_t Crot;
	isc_int32_t word;
	isc_int32_t bcount;
};

#define Ceor state->Ceor
#define Csum state->Csum
#define Crot state->Crot
#define word state->word
#define bcount state->bcount

#define times85(x)	((((((x<<2)+x)<<2)+x)<<2)+x)

static isc_result_t	byte_atob(int c, isc_buffer_t *target,
				  struct state *state);
static isc_result_t	putbyte(int c, isc_buffer_t *, struct state *state);
static isc_result_t	byte_btoa(int c, isc_buffer_t *, struct state *state);

/*
 * Decode ASCII-encoded byte c into binary representation and
 * place into *bufp, advancing bufp.
 */
static isc_result_t
byte_atob(int c, isc_buffer_t *target, struct state *state) {
	const char *s;
	if (c == 'z') {
		if (bcount != 0)
			return(DNS_R_SYNTAX);
		else {
			RETERR(putbyte(0, target, state));
			RETERR(putbyte(0, target, state));
			RETERR(putbyte(0, target, state));
			RETERR(putbyte(0, target, state));
		}
	} else if ((s = strchr(atob_digits, c)) != NULL) {
		if (bcount == 0) {
			word = (isc_int32_t)(s - atob_digits);
			++bcount;
		} else if (bcount < 4) {
			word = times85(word);
			word += (isc_int32_t)(s - atob_digits);
			++bcount;
		} else {
			word = times85(word);
			word += (isc_int32_t)(s - atob_digits);
			RETERR(putbyte((word >> 24) & 0xff, target, state));
			RETERR(putbyte((word >> 16) & 0xff, target, state));
			RETERR(putbyte((word >> 8) & 0xff, target, state));
			RETERR(putbyte(word & 0xff, target, state));
			word = 0;
			bcount = 0;
		}
	} else
		return(DNS_R_SYNTAX);
	return(ISC_R_SUCCESS);
}

/*
 * Compute checksum info and place c into target.
 */
static isc_result_t
putbyte(int c, isc_buffer_t *target, struct state *state) {
	isc_region_t tr;

	Ceor ^= c;
	Csum += c;
	Csum += 1;
	if ((Crot & 0x80000000)) {
		Crot <<= 1;
		Crot += 1;
	} else {
		Crot <<= 1;
	}
	Crot += c;
	isc_buffer_availableregion(target, &tr);
	if (tr.length < 1)
		return (ISC_R_NOSPACE);
	tr.base[0] = c;
	isc_buffer_add(target, 1);
	return (ISC_R_SUCCESS);
}

/*
 * Read the ASCII-encoded data from inbuf, of length inbuflen, and convert
 * it into T_UNSPEC (binary data) in outbuf, not to exceed outbuflen bytes;
 * outbuflen must be divisible by 4.  (Note: this is because outbuf is filled
 * in 4 bytes at a time.  If the actual data doesn't end on an even 4-byte
 * boundary, there will be no problem...it will be padded with 0 bytes, and
 * numbytes will indicate the correct number of bytes.  The main point is
 * that since the buffer is filled in 4 bytes at a time, even if there is
 * not a full 4 bytes of data at the end, there has to be room to 0-pad the
 * data, so the buffer must be of size divisible by 4).  Place the number of
 * output bytes in numbytes, and return a failure/success status.
 */

static isc_result_t
atob_tobuffer(isc_lex_t *lexer, isc_buffer_t *target) {
	long oeor, osum, orot;
	struct state statebuf, *state= &statebuf;
	isc_token_t token;
	char c;
	char *e;

	Ceor = Csum = Crot = word = bcount = 0;

	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_string,
				      ISC_FALSE));
	while (token.value.as_textregion.length != 0) {
		if ((c = token.value.as_textregion.base[0]) == 'x') {
			break;
		} else
			RETERR(byte_atob(c, target, state));
		isc_textregion_consume(&token.value.as_textregion, 1);
	}

	/*
	 * Number of bytes.
	 */
	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_number,
				      ISC_FALSE));
	if ((token.value.as_ulong % 4) != 0U) {
		unsigned long padding = 4 - (token.value.as_ulong % 4);
		if (isc_buffer_usedlength(target) < padding)
			return (DNS_R_SYNTAX);
		isc_buffer_subtract(target, padding);
	}

	/*
	 * Checksum.
	 */
	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_string,
				      ISC_FALSE));
	oeor = strtol(DNS_AS_STR(token), &e, 16);
	if (*e != 0)
		return (DNS_R_SYNTAX);

	/*
	 * Checksum.
	 */
	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_string,
				      ISC_FALSE));
	osum = strtol(DNS_AS_STR(token), &e, 16);
	if (*e != 0)
		return (DNS_R_SYNTAX);

	/*
	 * Checksum.
	 */
	RETERR(isc_lex_getmastertoken(lexer, &token, isc_tokentype_string,
				      ISC_FALSE));
	orot = strtol(DNS_AS_STR(token), &e, 16);
	if (*e != 0)
		return (DNS_R_SYNTAX);

	if ((oeor != Ceor) || (osum != Csum) || (orot != Crot))
		return(DNS_R_BADCKSUM);
	return (ISC_R_SUCCESS);
}

/*
 * Encode binary byte c into ASCII representation and place into *bufp,
 * advancing bufp.
 */
static isc_result_t
byte_btoa(int c, isc_buffer_t *target, struct state *state) {
	isc_region_t tr;

	isc_buffer_availableregion(target, &tr);
	Ceor ^= c;
	Csum += c;
	Csum += 1;
	if ((Crot & 0x80000000)) {
		Crot <<= 1;
		Crot += 1;
	} else {
		Crot <<= 1;
	}
	Crot += c;

	word <<= 8;
	word |= c;
	if (bcount == 3) {
		if (word == 0) {
			if (tr.length < 1)
				return (ISC_R_NOSPACE);
			tr.base[0] = 'z';
			isc_buffer_add(target, 1);
		} else {
		    register int tmp = 0;
		    register isc_int32_t tmpword = word;

		    if (tmpword < 0) {
			   /*
			    * Because some don't support u_long.
			    */
			tmp = 32;
			tmpword -= (isc_int32_t)(85 * 85 * 85 * 85 * 32);
		    }
		    if (tmpword < 0) {
			tmp = 64;
			tmpword -= (isc_int32_t)(85 * 85 * 85 * 85 * 32);
		    }
			if (tr.length < 5)
				return (ISC_R_NOSPACE);
			tr.base[0] = atob_digits[(tmpword /
					      (isc_int32_t)(85 * 85 * 85 * 85))
						+ tmp];
			tmpword %= (isc_int32_t)(85 * 85 * 85 * 85);
			tr.base[1] = atob_digits[tmpword / (85 * 85 * 85)];
			tmpword %= (85 * 85 * 85);
			tr.base[2] = atob_digits[tmpword / (85 * 85)];
			tmpword %= (85 * 85);
			tr.base[3] = atob_digits[tmpword / 85];
			tmpword %= 85;
			tr.base[4] = atob_digits[tmpword];
			isc_buffer_add(target, 5);
		}
		bcount = 0;
	} else {
		bcount += 1;
	}
	return (ISC_R_SUCCESS);
}


/*
 * Encode the binary data from inbuf, of length inbuflen, into a
 * target.  Return success/failure status
 */
static isc_result_t
btoa_totext(unsigned char *inbuf, int inbuflen, isc_buffer_t *target) {
	int inc;
	struct state statebuf, *state = &statebuf;
	char buf[sizeof("x 2000000000 ffffffff ffffffff ffffffff")];

	Ceor = Csum = Crot = word = bcount = 0;
	for (inc = 0; inc < inbuflen; inbuf++, inc++)
		RETERR(byte_btoa(*inbuf, target, state));

	while (bcount != 0)
		RETERR(byte_btoa(0, target, state));

	/*
	 * Put byte count and checksum information at end of buffer,
	 * delimited by 'x'
	 */
	snprintf(buf, sizeof(buf), "x %d %x %x %x", inbuflen, Ceor, Csum, Crot);
	return (str_totext(buf, target));
}


static void
default_fromtext_callback(dns_rdatacallbacks_t *callbacks, const char *fmt,
			  ...)
{
	va_list ap;

	UNUSED(callbacks);

	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	fprintf(stderr, "\n");
}

static void
fromtext_warneof(isc_lex_t *lexer, dns_rdatacallbacks_t *callbacks) {
	if (isc_lex_isfile(lexer) && callbacks != NULL) {
		const char *name = isc_lex_getsourcename(lexer);
		if (name == NULL)
			name = "UNKNOWN";
		(*callbacks->warn)(callbacks,
				   "%s:%lu: file does not end with newline",
				   name, isc_lex_getsourceline(lexer));
	}
}

static void
warn_badmx(isc_token_t *token, isc_lex_t *lexer,
	   dns_rdatacallbacks_t *callbacks)
{
	const char *file;
	unsigned long line;

	if (lexer != NULL) {
		file = isc_lex_getsourcename(lexer);
		line = isc_lex_getsourceline(lexer);
		(*callbacks->warn)(callbacks, "%s:%u: warning: '%s': %s",
				   file, line, DNS_AS_STR(*token),
				   dns_result_totext(DNS_R_MXISADDRESS));
	}
}

static void
warn_badname(dns_name_t *name, isc_lex_t *lexer,
	     dns_rdatacallbacks_t *callbacks)
{
	const char *file;
	unsigned long line;
	char namebuf[DNS_NAME_FORMATSIZE];

	if (lexer != NULL) {
		file = isc_lex_getsourcename(lexer);
		line = isc_lex_getsourceline(lexer);
		dns_name_format(name, namebuf, sizeof(namebuf));
		(*callbacks->warn)(callbacks, "%s:%u: warning: %s: %s",
				   file, line, namebuf,
				   dns_result_totext(DNS_R_BADNAME));
	}
}

static void
fromtext_error(void (*callback)(dns_rdatacallbacks_t *, const char *, ...),
	       dns_rdatacallbacks_t *callbacks, const char *name,
	       unsigned long line, isc_token_t *token, isc_result_t result)
{
	if (name == NULL)
		name = "UNKNOWN";

	if (token != NULL) {
		switch (token->type) {
		case isc_tokentype_eol:
			(*callback)(callbacks, "%s: %s:%lu: near eol: %s",
				    "dns_rdata_fromtext", name, line,
				    dns_result_totext(result));
			break;
		case isc_tokentype_eof:
			(*callback)(callbacks, "%s: %s:%lu: near eof: %s",
				    "dns_rdata_fromtext", name, line,
				    dns_result_totext(result));
			break;
		case isc_tokentype_number:
			(*callback)(callbacks, "%s: %s:%lu: near %lu: %s",
				    "dns_rdata_fromtext", name, line,
				    token->value.as_ulong,
				    dns_result_totext(result));
			break;
		case isc_tokentype_string:
		case isc_tokentype_qstring:
			(*callback)(callbacks, "%s: %s:%lu: near '%s': %s",
				    "dns_rdata_fromtext", name, line,
				    DNS_AS_STR(*token),
				    dns_result_totext(result));
			break;
		default:
			(*callback)(callbacks, "%s: %s:%lu: %s",
				    "dns_rdata_fromtext", name, line,
				    dns_result_totext(result));
			break;
		}
	} else {
		(*callback)(callbacks, "dns_rdata_fromtext: %s:%lu: %s",
			    name, line, dns_result_totext(result));
	}
}

dns_rdatatype_t
dns_rdata_covers(dns_rdata_t *rdata) {
	if (rdata->type == dns_rdatatype_rrsig)
		return (covers_rrsig(rdata));
	return (covers_sig(rdata));
}

isc_boolean_t
dns_rdatatype_ismeta(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_META) != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_issingleton(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_SINGLETON)
	    != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_notquestion(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_NOTQUESTION)
	    != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_questiononly(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_QUESTIONONLY)
	    != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_atparent(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_ATPARENT) != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdataclass_ismeta(dns_rdataclass_t rdclass) {

	if (rdclass == dns_rdataclass_reserved0
	    || rdclass == dns_rdataclass_none
	    || rdclass == dns_rdataclass_any)
		return (ISC_TRUE);

	return (ISC_FALSE);  /* Assume it is not a meta class. */
}

isc_boolean_t
dns_rdatatype_isdnssec(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_DNSSEC) != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_iszonecutauth(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type)
	     & (DNS_RDATATYPEATTR_DNSSEC | DNS_RDATATYPEATTR_ZONECUTAUTH))
	    != 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

isc_boolean_t
dns_rdatatype_isknown(dns_rdatatype_t type) {
	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_UNKNOWN)
	    == 0)
		return (ISC_TRUE);
	return (ISC_FALSE);
}

void
dns_rdata_exists(dns_rdata_t *rdata, dns_rdatatype_t type) {

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_INITIALIZED(rdata));

	rdata->data = NULL;
	rdata->length = 0;
	rdata->flags = DNS_RDATA_UPDATE;
	rdata->type = type;
	rdata->rdclass = dns_rdataclass_any;
}

void
dns_rdata_notexist(dns_rdata_t *rdata, dns_rdatatype_t type) {

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_INITIALIZED(rdata));

	rdata->data = NULL;
	rdata->length = 0;
	rdata->flags = DNS_RDATA_UPDATE;
	rdata->type = type;
	rdata->rdclass = dns_rdataclass_none;
}

void
dns_rdata_deleterrset(dns_rdata_t *rdata, dns_rdatatype_t type) {

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_INITIALIZED(rdata));

	rdata->data = NULL;
	rdata->length = 0;
	rdata->flags = DNS_RDATA_UPDATE;
	rdata->type = type;
	rdata->rdclass = dns_rdataclass_any;
}

void
dns_rdata_makedelete(dns_rdata_t *rdata) {
	REQUIRE(rdata != NULL);

	rdata->rdclass = dns_rdataclass_none;
}

const char *
dns_rdata_updateop(dns_rdata_t *rdata, dns_section_t section) {

	REQUIRE(rdata != NULL);
	REQUIRE(DNS_RDATA_INITIALIZED(rdata));

	switch (section) {
	case DNS_SECTION_PREREQUISITE:
		switch (rdata->rdclass) {
		case dns_rdataclass_none:
			switch (rdata->type) {
			case dns_rdatatype_any:
				return ("domain doesn't exist");
			default:
				return ("rrset doesn't exist");
			}
		case dns_rdataclass_any:
			switch (rdata->type) {
			case dns_rdatatype_any:
				return ("domain exists");
			default:
				return ("rrset exists (value independent)");
			}
		default:
			return ("rrset exists (value dependent)");
		}
	case DNS_SECTION_UPDATE:
		switch (rdata->rdclass) {
		case dns_rdataclass_none:
			return ("delete");
		case dns_rdataclass_any:
			switch (rdata->type) {
			case dns_rdatatype_any:
				return ("delete all rrsets");
			default:
				return ("delete rrset");
			}
		default:
			return ("add");
		}
	}
	return ("invalid");
}
