+#define TLS13_AES_128_GCM_SHA256_BYTES ((const unsigned char *)"\x13\x01")
+#define TLS13_AES_256_GCM_SHA384_BYTES ((const unsigned char *)"\x13\x02")
+
+static int psk_find_session_cb(SSL *ssl, const unsigned char *identity,
+ size_t identity_len, SSL_SESSION **sess)
+{
+ SSL_SESSION *tmpsess = NULL;
+ unsigned char *key;
+ long key_len;
+ const SSL_CIPHER *cipher = NULL;
+
+ if (strlen(psk_identity) != identity_len
+ || memcmp(psk_identity, identity, identity_len) != 0) {
+ *sess = NULL;
+ return 1;
+ }
+
+ if (psksess != NULL) {
+ SSL_SESSION_up_ref(psksess);
+ *sess = psksess;
+ return 1;
+ }
+
+ key = OPENSSL_hexstr2buf(psk_key, &key_len);
+ if (key == NULL) {
+ BIO_printf(bio_err, "Could not convert PSK key '%s' to buffer\n",
+ psk_key);
+ return 0;
+ }
+
+ /* We default to SHA256 */
+ cipher = SSL_CIPHER_find(ssl, tls13_aes128gcmsha256_id);
+ if (cipher == NULL) {
+ BIO_printf(bio_err, "Error finding suitable ciphersuite\n");
+ OPENSSL_free(key);
+ return 0;
+ }
+
+ tmpsess = SSL_SESSION_new();
+ if (tmpsess == NULL
+ || !SSL_SESSION_set1_master_key(tmpsess, key, key_len)
+ || !SSL_SESSION_set_cipher(tmpsess, cipher)
+ || !SSL_SESSION_set_protocol_version(tmpsess, SSL_version(ssl))) {
+ OPENSSL_free(key);
+ return 0;
+ }
+ OPENSSL_free(key);
+ *sess = tmpsess;
+
+ return 1;
+}
+