Adding upstream version 1:9.18.19.upstream/1%9.18.19

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2367 insertions, 0 deletions

diff --git a/lib/dns/rdata.c b/lib/dns/rdata.c
new file mode 100644
index 0000000..b7f9ed2
--- /dev/null
+++ b/lib/dns/rdata.c
@@ -0,0 +1,2367 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * 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 https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <ctype.h>
+#include <inttypes.h>
+#include <stdbool.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/result.h>
+#include <isc/string.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/fixedname.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/rdataset.h>
+#include <dns/rdatastruct.h>
+#include <dns/rdatatype.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,    \
+		const dns_name_t *origin, unsigned int options, \
+		isc_buffer_t *target, dns_rdatacallbacks_t *callbacks
+
+#define CALL_FROMTEXT rdclass, type, lexer, origin, options, target, callbacks
+
+#define ARGS_TOTEXT \
+	dns_rdata_t *rdata, dns_rdata_textctx_t *tctx, isc_buffer_t *target
+
+#define CALL_TOTEXT rdata, tctx, 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 CALL_FROMWIRE rdclass, type, source, dctx, options, target
+
+#define ARGS_TOWIRE \
+	dns_rdata_t *rdata, dns_compress_t *cctx, isc_buffer_t *target
+
+#define CALL_TOWIRE rdata, cctx, target
+
+#define ARGS_COMPARE const dns_rdata_t *rdata1, const dns_rdata_t *rdata2
+
+#define CALL_COMPARE rdata1, rdata2
+
+#define ARGS_FROMSTRUCT \
+	int rdclass, dns_rdatatype_t type, void *source, isc_buffer_t *target
+
+#define CALL_FROMSTRUCT rdclass, type, source, target
+
+#define ARGS_TOSTRUCT const dns_rdata_t *rdata, void *target, isc_mem_t *mctx
+
+#define CALL_TOSTRUCT rdata, target, mctx
+
+#define ARGS_FREESTRUCT void *source
+
+#define CALL_FREESTRUCT source
+
+#define ARGS_ADDLDATA                                \
+	dns_rdata_t *rdata, const dns_name_t *owner, \
+		dns_additionaldatafunc_t add, void *arg
+
+#define CALL_ADDLDATA rdata, owner, add, arg
+
+#define ARGS_DIGEST dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg
+
+#define CALL_DIGEST rdata, digest, arg
+
+#define ARGS_CHECKOWNER                                   \
+	const dns_name_t *name, dns_rdataclass_t rdclass, \
+		dns_rdatatype_t type, bool wildcard
+
+#define CALL_CHECKOWNER name, rdclass, type, wildcard
+
+#define ARGS_CHECKNAMES \
+	dns_rdata_t *rdata, const dns_name_t *owner, dns_name_t *bad
+
+#define CALL_CHECKNAMES rdata, owner, bad
+
+/*%
+ * Context structure for the totext_ functions.
+ * Contains formatting options for rdata-to-text
+ * conversion.
+ */
+typedef struct dns_rdata_textctx {
+	const dns_name_t *origin;      /*%< Current origin, or NULL. */
+	dns_masterstyle_flags_t 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, bool 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
+commatxt_fromtext(isc_textregion_t *source, bool comma, isc_buffer_t *target);
+
+static isc_result_t
+commatxt_totext(isc_region_t *source, bool quote, bool comma,
+		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 bool
+name_prefix(dns_name_t *name, const dns_name_t *origin, dns_name_t *target);
+
+static unsigned int
+name_length(const 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, uint32_t flags, isc_region_t *src, isc_buffer_t *target);
+
+static bool
+buffer_empty(isc_buffer_t *source);
+
+static void
+buffer_fromregion(isc_buffer_t *buffer, isc_region_t *region);
+
+static isc_result_t
+uint32_tobuffer(uint32_t, isc_buffer_t *target);
+
+static isc_result_t
+uint16_tobuffer(uint32_t, isc_buffer_t *target);
+
+static isc_result_t
+uint8_tobuffer(uint32_t, isc_buffer_t *target);
+
+static isc_result_t
+name_tobuffer(const dns_name_t *name, isc_buffer_t *target);
+
+static uint32_t
+uint32_fromregion(isc_region_t *region);
+
+static uint16_t
+uint16_fromregion(isc_region_t *region);
+
+static uint8_t
+uint8_fromregion(isc_region_t *region);
+
+static 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 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(const 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 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 isc_result_t generic_fromtext_key(ARGS_FROMTEXT);
+
+static isc_result_t generic_totext_key(ARGS_TOTEXT);
+
+static isc_result_t generic_fromwire_key(ARGS_FROMWIRE);
+
+static isc_result_t generic_fromstruct_key(ARGS_FROMSTRUCT);
+
+static isc_result_t generic_tostruct_key(ARGS_TOSTRUCT);
+
+static 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);
+
+static isc_result_t generic_fromtext_in_svcb(ARGS_FROMTEXT);
+static isc_result_t generic_totext_in_svcb(ARGS_TOTEXT);
+static isc_result_t generic_fromwire_in_svcb(ARGS_FROMWIRE);
+static isc_result_t generic_towire_in_svcb(ARGS_TOWIRE);
+static isc_result_t generic_fromstruct_in_svcb(ARGS_FROMSTRUCT);
+static isc_result_t generic_tostruct_in_svcb(ARGS_TOSTRUCT);
+static void generic_freestruct_in_svcb(ARGS_FREESTRUCT);
+static isc_result_t generic_additionaldata_in_svcb(ARGS_ADDLDATA);
+static bool generic_checknames_in_svcb(ARGS_CHECKNAMES);
+static isc_result_t
+generic_rdata_in_svcb_first(dns_rdata_in_svcb_t *);
+static isc_result_t
+generic_rdata_in_svcb_next(dns_rdata_in_svcb_t *);
+static void
+generic_rdata_in_svcb_current(dns_rdata_in_svcb_t *, isc_region_t *);
+
+/*% INT16 Size */
+#define NS_INT16SZ 2
+/*% IPv6 Address Size */
+#define NS_LOCATORSZ 8
+
+/*
+ * Active Directory 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 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 void
+name_duporclone(const dns_name_t *source, isc_mem_t *mctx, dns_name_t *target) {
+	if (mctx != NULL) {
+		dns_name_dup(source, mctx, target);
+	} else {
+		dns_name_clone(source, target);
+	}
+}
+
+static 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);
+	memmove(copy, source, length);
+
+	return (copy);
+}
+
+static isc_result_t
+typemap_fromtext(isc_lex_t *lexer, isc_buffer_t *target, bool 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;
+	bool first = true;
+
+	max_used = 0;
+	bm[0] = 0;
+	end = 0;
+
+	do {
+		RETERR(isc_lex_getmastertoken(lexer, &token,
+					      isc_tokentype_string, 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 = 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 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;
+	bool first = true;
+
+	for (i = 0; i < sr->length; i += len) {
+		if (tctx != NULL &&
+		    (tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0)
+		{
+			RETERR(str_totext(tctx->linebreak, target));
+			first = 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 = 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, bool allow_empty) {
+	unsigned int window, lastwindow = 0;
+	unsigned int len;
+	bool first = 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 = 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;
+	bool use_default = 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;
+	bool use_default = 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;
+	bool use_default = false;
+	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;
+	bool use_default = 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, (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,
+				      false));
+	if (token.value.as_ulong > 65535U) {
+		return (ISC_R_RANGE);
+	}
+	isc_buffer_allocate(mctx, &buf, token.value.as_ulong);
+
+	if (token.value.as_ulong != 0U) {
+		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,
+		   const 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;
+	bool unknown;
+
+	REQUIRE(origin == NULL || dns_name_isabsolute(origin));
+	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,
+					true);
+	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 = 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, false);
+			if (result == ISC_R_SUCCESS) {
+				isc_lex_ungettoken(lexer, &token);
+			}
+		}
+
+		if (result == ISC_R_SUCCESS) {
+			unknown = 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;
+	bool use_default = false;
+	unsigned int cur;
+
+	REQUIRE(rdata != NULL);
+	REQUIRE(tctx->origin == NULL || dns_name_isabsolute(tctx->origin));
+
+	/*
+	 * 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, const 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, const dns_name_t *origin,
+		    dns_masterstyle_flags_t 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;
+	bool use_default = 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(const dns_rdata_t *rdata, void *target, isc_mem_t *mctx) {
+	isc_result_t result = ISC_R_NOTIMPLEMENTED;
+	bool use_default = false;
+
+	REQUIRE(rdata != NULL);
+	REQUIRE(DNS_RDATA_VALIDFLAGS(rdata));
+	REQUIRE((rdata->flags & DNS_RDATA_UPDATE) == 0);
+
+	TOSTRUCTSWITCH
+
+	if (use_default) {
+		(void)NULL;
+	}
+
+	return (result);
+}
+
+void
+dns_rdata_freestruct(void *source) {
+	dns_rdatacommon_t *common = source;
+	REQUIRE(common != NULL);
+
+	FREESTRUCTSWITCH
+}
+
+isc_result_t
+dns_rdata_additionaldata(dns_rdata_t *rdata, const dns_name_t *owner,
+			 dns_additionaldatafunc_t add, void *arg) {
+	isc_result_t result = ISC_R_NOTIMPLEMENTED;
+	bool use_default = 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;
+	bool use_default = 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);
+}
+
+bool
+dns_rdata_checkowner(const dns_name_t *name, dns_rdataclass_t rdclass,
+		     dns_rdatatype_t type, bool wildcard) {
+	bool result;
+
+	CHECKOWNERSWITCH
+	return (result);
+}
+
+bool
+dns_rdata_checknames(dns_rdata_t *rdata, const dns_name_t *owner,
+		     dns_name_t *bad) {
+	bool 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(const dns_name_t *name) {
+	return (name->length);
+}
+
+static isc_result_t
+commatxt_totext(isc_region_t *source, bool quote, bool comma,
+		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);
+	}
+
+	if (quote) {
+		if (tl < 1) {
+			return (ISC_R_NOSPACE);
+		}
+		*tp++ = '"';
+		tl--;
+	}
+	while (n--) {
+		/*
+		 * \DDD space (0x20) if not quoting.
+		 */
+		if (*sp < (quote ? ' ' : '!') || *sp >= 0x7f) {
+			if (tl < 4) {
+				return (ISC_R_NOSPACE);
+			}
+			*tp++ = '\\';
+			*tp++ = '0' + ((*sp / 100) % 10);
+			*tp++ = '0' + ((*sp / 10) % 10);
+			*tp++ = '0' + (*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 (;) unless comma is set.
+		 * If comma is set, then only escape commas (,).
+		 */
+		if (*sp == '"' || *sp == '\\' || (comma && *sp == ',') ||
+		    (!comma && !quote && (*sp == '@' || *sp == ';')))
+		{
+			if (tl < 2) {
+				return (ISC_R_NOSPACE);
+			}
+			*tp++ = '\\';
+			tl--;
+			/*
+			 * Perform comma escape processing.
+			 * ',' => '\\,'
+			 * '\' => '\\\\'
+			 */
+			if (comma && (*sp == ',' || *sp == '\\')) {
+				if (tl < ((*sp == '\\') ? 3 : 2)) {
+					return (ISC_R_NOSPACE);
+				}
+				*tp++ = '\\';
+				tl--;
+				if (*sp == '\\') {
+					*tp++ = '\\';
+					tl--;
+				}
+			}
+		}
+		if (tl < 1) {
+			return (ISC_R_NOSPACE);
+		}
+		*tp++ = *sp++;
+		tl--;
+	}
+	if (quote) {
+		if (tl < 1) {
+			return (ISC_R_NOSPACE);
+		}
+		*tp++ = '"';
+		tl--;
+		POST(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_totext(isc_region_t *source, bool quote, isc_buffer_t *target) {
+	return (commatxt_totext(source, quote, false, target));
+}
+
+static isc_result_t
+commatxt_fromtext(isc_textregion_t *source, bool comma, isc_buffer_t *target) {
+	isc_region_t tregion;
+	bool escape = false, comma_escape = false, seen_comma = false;
+	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;
+	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 = true;
+			continue;
+		}
+		escape = false;
+		/*
+		 * Level 1 escape processing complete.
+		 * If comma is set perform comma escape processing.
+		 *
+		 * Level 1	Level 2		ALPN's
+		 * h1\,h2   =>	h1,h2   =>	h1 and h2
+		 * h1\\,h2  =>	h1\,h2  =>	h1,h2
+		 * h1\\h2   =>	h1\h2   =>	h1h2
+		 * h1\\\\h2 =>	h1\\h2  =>	h1\h2
+		 */
+		if (comma && !comma_escape && c == ',') {
+			seen_comma = true;
+			break;
+		}
+		if (comma && !comma_escape && c == '\\') {
+			comma_escape = true;
+			continue;
+		}
+		comma_escape = false;
+		if (nrem == 0) {
+			return ((tregion.length <= 256U) ? ISC_R_NOSPACE
+							 : DNS_R_SYNTAX);
+		}
+		*t++ = c;
+		nrem--;
+	}
+
+	/*
+	 * Incomplete escape processing?
+	 */
+	if (escape || (comma && comma_escape)) {
+		return (DNS_R_SYNTAX);
+	}
+
+	if (comma) {
+		/*
+		 * Disallow empty ALPN at start (",h1") or in the
+		 * middle ("h1,,h2").
+		 */
+		if (s == source->base || (seen_comma && s == source->base + 1))
+		{
+			return (DNS_R_SYNTAX);
+		}
+		isc_textregion_consume(source, s - source->base);
+		/*
+		 * Disallow empty ALPN at end ("h1,").
+		 */
+		if (seen_comma && source->length == 0) {
+			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_fromtext(isc_textregion_t *source, isc_buffer_t *target) {
+	return (commatxt_fromtext(source, false, target));
+}
+
+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 < ' ' || *sp >= 0x7f) {
+				if (tl < 4) {
+					return (ISC_R_NOSPACE);
+				}
+				*tp++ = '\\';
+				*tp++ = '0' + ((*sp / 100) % 10);
+				*tp++ = '0' + ((*sp / 10) % 10);
+				*tp++ = '0' + (*sp % 10);
+				sp++;
+				tl -= 4;
+				continue;
+			}
+			/* double quote, backslash */
+			if (*sp == '"' || *sp == '\\') {
+				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--;
+	POST(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;
+	bool escape;
+	unsigned int n, nrem;
+	char *s;
+	unsigned char *t0, *t;
+	int d;
+	int c;
+
+	s = source->base;
+	n = source->length;
+	escape = 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 = true;
+				continue;
+			}
+			escape = 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 bool
+name_prefix(dns_name_t *name, const 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 (true);
+
+return_false:
+	*target = *name;
+	return (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, uint32_t flags, 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);
+
+	/*
+	 * An IPv6 address ending in "::" breaks YAML
+	 * parsing, so append 0 in that case.
+	 */
+	if (af == AF_INET6 && (flags & DNS_STYLEFLAG_YAML) != 0) {
+		isc_region_t r;
+		isc_buffer_usedregion(target, &r);
+		if (r.length > 0 && r.base[r.length - 1] == ':') {
+			if (isc_buffer_availablelength(target) == 0) {
+				return (ISC_R_NOSPACE);
+			}
+			isc_buffer_putmem(target, (const unsigned char *)"0",
+					  1);
+		}
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static bool
+buffer_empty(isc_buffer_t *source) {
+	return ((source->current == source->active) ? true : 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(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(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, (uint16_t)value);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+uint8_tobuffer(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, (uint8_t)value);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+name_tobuffer(const dns_name_t *name, isc_buffer_t *target) {
+	isc_region_t r;
+	dns_name_toregion(name, &r);
+	return (isc_buffer_copyregion(target, &r));
+}
+
+static uint32_t
+uint32_fromregion(isc_region_t *region) {
+	uint32_t value;
+
+	REQUIRE(region->length >= 4);
+	value = (uint32_t)region->base[0] << 24;
+	value |= (uint32_t)region->base[1] << 16;
+	value |= (uint32_t)region->base[2] << 8;
+	value |= (uint32_t)region->base[3];
+	return (value);
+}
+
+static uint16_t
+uint16_consume_fromregion(isc_region_t *region) {
+	uint16_t r = uint16_fromregion(region);
+
+	isc_region_consume(region, 2);
+	return (r);
+}
+
+static uint16_t
+uint16_fromregion(isc_region_t *region) {
+	REQUIRE(region->length >= 2);
+
+	return ((region->base[0] << 8) | region->base[1]);
+}
+
+static uint8_t
+uint8_fromregion(isc_region_t *region) {
+	REQUIRE(region->length >= 1);
+
+	return (region->base[0]);
+}
+
+static uint8_t
+uint8_consume_fromregion(isc_region_t *region) {
+	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 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),
+				   isc_result_totext(DNS_R_MXISADDRESS));
+	}
+}
+
+static void
+warn_badname(const 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,
+				   isc_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,
+				    isc_result_totext(result));
+			break;
+		case isc_tokentype_eof:
+			(*callback)(callbacks, "%s: %s:%lu: near eof: %s",
+				    "dns_rdata_fromtext", name, line,
+				    isc_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,
+				    isc_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),
+				    isc_result_totext(result));
+			break;
+		default:
+			(*callback)(callbacks, "%s: %s:%lu: %s",
+				    "dns_rdata_fromtext", name, line,
+				    isc_result_totext(result));
+			break;
+		}
+	} else {
+		(*callback)(callbacks, "dns_rdata_fromtext: %s:%lu: %s", name,
+			    line, isc_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));
+}
+
+bool
+dns_rdatatype_ismeta(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_META) != 0) {
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_issingleton(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_SINGLETON) != 0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_notquestion(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_NOTQUESTION) !=
+	    0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_questiononly(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_QUESTIONONLY) !=
+	    0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_atcname(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_ATCNAME) != 0) {
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_atparent(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_ATPARENT) != 0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_followadditional(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) &
+	     DNS_RDATATYPEATTR_FOLLOWADDITIONAL) != 0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdataclass_ismeta(dns_rdataclass_t rdclass) {
+	if (rdclass == dns_rdataclass_reserved0 ||
+	    rdclass == dns_rdataclass_none || rdclass == dns_rdataclass_any)
+	{
+		return (true);
+	}
+
+	return (false); /* Assume it is not a meta class. */
+}
+
+bool
+dns_rdatatype_isdnssec(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_DNSSEC) != 0) {
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_iszonecutauth(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_ZONECUTAUTH) !=
+	    0)
+	{
+		return (true);
+	}
+	return (false);
+}
+
+bool
+dns_rdatatype_isknown(dns_rdatatype_t type) {
+	if ((dns_rdatatype_attributes(type) & DNS_RDATATYPEATTR_UNKNOWN) == 0) {
+		return (true);
+	}
+	return (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");
+}