lowercase: dname lookup format in lowercase.

src/knot/dnssec/nsec-chain.c

@@ -113,6 +113,7 @@ static int connect_nsec_nodes(zone_node_t *a, zone_node_t *b,
 
 	knot_rrset_t old_nsec = node_rrset(a, KNOT_RRTYPE_NSEC);
 	if (!knot_rrset_empty(&old_nsec)) {
+		/*! \todo[lowercase]: Case insensitive comparison needed. */
 		if (knot_rrset_equal(&new_nsec, &old_nsec,
 		                     KNOT_RRSET_COMPARE_WHOLE)) {
 			// current NSEC is valid, do nothing

src/libknot/dname.c

@@ -803,6 +803,9 @@ int knot_dname_lf(uint8_t *dst, const knot_dname_t *src, const uint8_t *pkt)
 	while(sp != lstack) {          /* consume stack */
 		l = *--sp; /* fetch rightmost label */
 		memcpy(dst, l+1, *l);  /* write label */
+		for (int i = 0; i < *l; ++i) {   /* convert to lowercase */
+			dst[i] = knot_tolower(dst[i]);
+		}
 		dst += *l;
 		*dst++ = '\0';         /* label separator */
 		*len += *l + 1;