Function kr_rplan_push() fails again with null name.

Introduced kr_rplan_push_empty() to create empty query for DNS cookies.

lib/resolve.c

@@ -396,7 +396,16 @@ static int resolve_query(struct kr_request *request, const knot_pkt_t *packet)
 	const knot_dname_t *qname = knot_pkt_qname(packet);
 	uint16_t qclass = knot_pkt_qclass(packet);
 	uint16_t qtype = knot_pkt_qtype(packet);
-	struct kr_query *qry = kr_rplan_push(rplan, NULL, qname, qclass, qtype);
+	struct kr_query *qry = NULL;
+
+	if (qname != NULL) {
+		qry = kr_rplan_push(rplan, NULL, qname, qclass, qtype);
+	} else if (knot_wire_get_qdcount(packet->wire) == 0 &&
+                   knot_pkt_has_edns(packet) &&
+                   knot_edns_has_option(packet->opt_rr, KNOT_EDNS_OPTION_COOKIE)) {
+		/* Plan empty query only for cookies. */
+		qry = kr_rplan_push_empty(rplan, NULL);
+	}
 	if (!qry) {
 		return KNOT_STATE_FAIL;
 	}

lib/rplan.c

@@ -107,8 +107,9 @@ bool kr_rplan_empty(struct kr_rplan *rplan)
 	return rplan->pending.len == 0;
 }
 
-struct kr_query *kr_rplan_push(struct kr_rplan *rplan, struct kr_query *parent,
-                               const knot_dname_t *name, uint16_t cls, uint16_t type)
+static struct kr_query *kr_rplan_push_query(struct kr_rplan *rplan,
+                                            struct kr_query *parent,
+                                            const knot_dname_t *name)
 {
 	if (rplan == NULL) {
 		return NULL;
@@ -124,8 +125,7 @@ struct kr_query *kr_rplan_push(struct kr_rplan *rplan, struct kr_query *parent,
 	if (qry == NULL) {
 		return NULL;
 	}
-	qry->sclass = cls;
-	qry->stype = type;
+	/* Class and type must be set outside this function. */
 	qry->flags = rplan->request->options;
 	qry->parent = parent;
 	qry->ns.addr[0].ip.sa_family = AF_UNSPEC;
@@ -133,6 +133,41 @@ struct kr_query *kr_rplan_push(struct kr_rplan *rplan, struct kr_query *parent,
 	kr_zonecut_init(&qry->zone_cut, (const uint8_t *)"", rplan->pool);
 	array_push(rplan->pending, qry);
 
+	return qry;
+}
+
+struct kr_query *kr_rplan_push_empty(struct kr_rplan *rplan, struct kr_query *parent)
+{
+	if (rplan == NULL) {
+		return NULL;
+	}
+
+	struct kr_query *qry = kr_rplan_push_query(rplan, parent, NULL);
+	if (qry == NULL) {
+		return NULL;
+	}
+
+	WITH_DEBUG {
+	DEBUG_MSG(parent, "plan '%s' type '%s'\n", "", "");
+	}
+	return qry;
+}
+
+struct kr_query *kr_rplan_push(struct kr_rplan *rplan, struct kr_query *parent,
+                               const knot_dname_t *name, uint16_t cls, uint16_t type)
+{
+	if (rplan == NULL || name == NULL) {
+		return NULL;
+	}
+
+	struct kr_query *qry = kr_rplan_push_query(rplan, parent, name);
+	if (qry == NULL) {
+		return NULL;
+	}
+
+	qry->sclass = cls;
+	qry->stype = type;
+
 	WITH_DEBUG {
 	char name_str[KNOT_DNAME_MAXLEN], type_str[16];
 	knot_dname_to_str(name_str, name, sizeof(name_str));

lib/rplan.h

@@ -120,6 +120,17 @@ void kr_rplan_deinit(struct kr_rplan *rplan);
 KR_EXPORT KR_PURE
 bool kr_rplan_empty(struct kr_rplan *rplan);
 
+/**
+ * Push empty query to the top of the resolution plan.
+ * @note This query serves as a cookie query only.
+ * @param rplan plan instance
+ * @param parent query parent (or NULL)
+ * @return query instance or NULL
+ */
+KR_EXPORT
+struct kr_query *kr_rplan_push_empty(struct kr_rplan *rplan,
+                                     struct kr_query *parent);
+
 /**
  * Push a query to the top of the resolution plan.
  * @note This means that this query takes precedence before all pending queries.

tests/test_rplan.c

@@ -32,8 +32,7 @@ static void test_rplan_params(void **state)
 
 	struct kr_rplan rplan;
 	assert_int_equal(kr_rplan_init(&rplan, NULL, NULL), KNOT_EOK);
-	// TODO: add test for empty dname
-//	assert_null((void *)kr_rplan_push(&rplan, NULL, NULL, 0, 0));
+	assert_null((void *)kr_rplan_push(&rplan, NULL, NULL, 0, 0));
 	assert_int_equal(kr_rplan_pop(&rplan, NULL), KNOT_EINVAL);
 	assert_true(kr_rplan_empty(&rplan) == true);
 	kr_rplan_deinit(&rplan);