libknot: add knot_dname_with_null()

distro/pkg/deb/libknot15.symbols

@@ -53,6 +53,7 @@ libknot.so.15 libknot15 #MINVER#
  knot_dname_to_wire@Base 3.4.0
  knot_dname_unpack@Base 3.4.0
  knot_dname_wire_check@Base 3.4.0
+ knot_dname_with_null@Base 3.4.3
  knot_dnssec_alg_names@Base 3.4.0
  knot_edns_add_option@Base 3.4.0
  knot_edns_alignment_size@Base 3.4.0

src/libknot/dname.c

@@ -706,6 +706,17 @@ bool knot_dname_is_case_equal(const knot_dname_t *d1, const knot_dname_t *d2)
 	return dname_is_equal(d1, d2, true);
 }
 
+_public_
+bool knot_dname_with_null(const knot_dname_t *name)
+{
+	if (name == NULL) {
+		return false;
+	}
+
+	size_t size = knot_dname_size(name);
+	return (size != strnlen((const char *)name, size) + 1);
+}
+
 _public_
 size_t knot_dname_prefixlen(const uint8_t *name, unsigned nlabels)
 {

src/libknot/dname.h

@@ -290,6 +290,17 @@ bool knot_dname_is_equal(const knot_dname_t *d1, const knot_dname_t *d2);
 _pure_
 bool knot_dname_is_case_equal(const knot_dname_t *d1, const knot_dname_t *d2);
 
+/*!
+ * \brief Checks the domain name if it contains '\0' byte within a label.
+ *
+ * \param name  Domain name.
+ *
+ * \retval true if a zero byte is included
+ * \retval false if a zero byte isn't included
+ */
+_pure_
+bool knot_dname_with_null(const knot_dname_t *name);
+
 /*!
  * \brief Count length of the N first labels.
  *