Added function for non-const getting of next RDATA

src/dnslib/rrset.c

@@ -129,6 +129,18 @@ dnslib_rdata_t *dnslib_rrset_get_rdata(dnslib_rrset_t *rrset)
 
 /*----------------------------------------------------------------------------*/
 
+dnslib_rdata_t *dnslib_rrset_rdata_get_next(dnslib_rrset_t *rrset,
+                                            dnslib_rdata_t *rdata)
+{
+	if (rdata->next == rrset->rdata) {
+		return NULL;
+	} else {
+		return rdata->next;
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+
 const dnslib_rrset_t *dnslib_rrset_rrsigs(const dnslib_rrset_t *rrset)
 {
 	if (rrset == NULL) {

src/dnslib/rrset.h

@@ -165,6 +165,9 @@ const dnslib_rdata_t *dnslib_rrset_rdata_next(const dnslib_rrset_t *rrset,
  */
 dnslib_rdata_t *dnslib_rrset_get_rdata(dnslib_rrset_t *rrset);
 
+dnslib_rdata_t *dnslib_rrset_rdata_get_next(dnslib_rrset_t *rrset,
+                                            dnslib_rdata_t *rdata);
+
 /*!
  * \brief Returns the set of RRSIGs covering the given RRSet.
  *