diff --git a/lib/dns/include/dns/rdata.h b/lib/dns/include/dns/rdata.h
index 27a1892ec3..7da8f5370e 100644
--- a/lib/dns/include/dns/rdata.h
+++ b/lib/dns/include/dns/rdata.h
@@ -477,6 +477,51 @@ dns_rdata_additionaldata(dns_rdata_t *rdata, dns_additionaldatafunc_t add,
  *	Many other results are possible if not successful.
  */
 
+dns_result_t
+dns_rdata_digest(dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg);
+/*
+ * Send 'rdata' in DNSSEC canonical form to 'digest'.
+ *
+ * Note:
+ *	'digest' may be called more than once by dns_rdata_digest().  The
+ *	concatenation of all the regions, in the order they were given
+ *	to 'digest', will be the DNSSEC canonical form of 'rdata'.
+ *
+ * Requires:
+ *
+ *	'rdata' is a valid, non-empty rdata.
+ *
+ *	'digest' is a valid dns_digestfunc_t.
+ *
+ * Ensures:
+ *
+ *	If successful, then all of the rdata's data has been sent, in
+ *	DNSSEC canonical form, to 'digest'.
+ *
+ *	If digest() returns something other than DNS_R_SUCCESS, that result
+ *	will be returned as the result of dns_rdata_digest().
+ *
+ * Returns:
+ *
+ *	DNS_R_SUCCESS
+ *
+ *	Many other results are possible if not successful.
+ */
+
+dns_rdatatype_t
+dns_rdata_covers(dns_rdata_t *rdata);
+/*
+ * Return the rdatatype that this type covers.
+ *
+ * Requires:
+ *	'rdata' is a valid, non-empty rdata.
+ *
+ *	'rdata' is a type that covers other rdata types.
+ *
+ * Returns:
+ *	The type covered.
+ */
+
 ISC_LANG_ENDDECLS
 
 #endif /* DNS_RDATA_H */
diff --git a/lib/dns/rdata.c b/lib/dns/rdata.c
index e76fca7820..e647644381 100644
--- a/lib/dns/rdata.c
+++ b/lib/dns/rdata.c
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
- /* $Id: rdata.c,v 1.58 1999/08/16 06:45:13 gson Exp $ */
+ /* $Id: rdata.c,v 1.59 1999/08/31 22:08:07 halley Exp $ */
 
 #include <config.h>
 
@@ -548,7 +548,7 @@ dns_result_t
 dns_rdata_additionaldata(dns_rdata_t *rdata, dns_additionaldatafunc_t add,
 			 void *arg)
 {
-	dns_result_t result = ISC_R_SUCCESS;
+	dns_result_t result = DNS_R_NOTIMPLEMENTED;
 	isc_boolean_t use_default = ISC_FALSE;
 
 	/*
@@ -567,6 +567,26 @@ dns_rdata_additionaldata(dns_rdata_t *rdata, dns_additionaldatafunc_t add,
 	return (result);
 }
 
+dns_result_t
+dns_rdata_digest(dns_rdata_t *rdata, dns_digestfunc_t digest, void *arg) {
+	dns_result_t result = DNS_R_NOTIMPLEMENTED;
+	isc_boolean_t use_default = ISC_FALSE;
+
+	/*
+	 * Send 'rdata' in DNSSEC canonical form to 'digest'.
+	 */
+
+	REQUIRE(rdata != NULL);
+	REQUIRE(digest != NULL);
+
+	DIGESTSWITCH
+
+	if (use_default)
+		(void)NULL;
+
+	return (result);
+}
+
 dns_result_t
 dns_rdataclass_fromtext(dns_rdataclass_t *classp, isc_textregion_t *source) {
 	int i = 0;
@@ -1393,7 +1413,13 @@ fromtext_error(void (*callback)(dns_rdatacallbacks_t *, char *, ...),
 	}
 }
 
-static isc_boolean_t ismeta(unsigned int code, struct tbl *table) {
+dns_rdatatype_t
+dns_rdata_covers(dns_rdata_t *rdata) {
+	return (covers_sig(rdata));
+}
+
+static isc_boolean_t
+ismeta(unsigned int code, struct tbl *table) {
 	struct tbl *t;
 	REQUIRE(code < 65536);
 	for (t = table; t->name != NULL; t++) {