1 files changed, 57 insertions, 0 deletions
diff --git a/lib/cookies/lru_cache.h b/lib/cookies/lru_cache.h
new file mode 100644
index 0000000..a0f6cab
--- /dev/null
+++ b/lib/cookies/lru_cache.h
@@ -0,0 +1,57 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <netinet/in.h>
+#include <stdint.h>
+
+#if ENABLE_COOKIES
+#include <libknot/rrtype/opt.h>
+#include <libknot/rrtype/opt-cookie.h>
+#else
+#define KNOT_OPT_COOKIE_CLNT 8
+#define KNOT_OPT_COOKIE_SRVR_MAX 32
+#endif /* ENABLE_COOKIES */
+
+#include "lib/defines.h"
+#include "lib/generic/lru.h"
+
+/** Maximal size of a cookie option. */
+#define KR_COOKIE_OPT_MAX_LEN (KNOT_EDNS_OPTION_HDRLEN + KNOT_OPT_COOKIE_CLNT + KNOT_OPT_COOKIE_SRVR_MAX)
+
+/**
+ * Cookie option entry.
+ */
+struct cookie_opt_data {
+	uint8_t opt_data[KR_COOKIE_OPT_MAX_LEN];
+};
+
+/**
+ * DNS cookies tracking.
+ */
+typedef lru_t(struct cookie_opt_data) kr_cookie_lru_t;
+
+/**
+ * @brief Obtain LRU cache entry.
+ *
+ * @param cache cookie LRU cache
+ * @param sa socket address serving as key
+ * @return pointer to cached option or NULL if not found or error occurred
+ */
+KR_EXPORT
+const uint8_t *kr_cookie_lru_get(kr_cookie_lru_t *cache,
+                                 const struct sockaddr *sa);
+
+/**
+ * @brief Stores cookie option into LRU cache.
+ *
+ * @param cache cookie LRU cache
+ * @param sa socket address serving as key
+ * @param opt cookie option to be stored
+ * @return kr_ok() or error code
+ */
+KR_EXPORT
+int kr_cookie_lru_set(kr_cookie_lru_t *cache, const struct sockaddr *sa,
+                      uint8_t *opt);