fixup! sys/net/gcoap: reduce insanity of hack

sys/include/net/nanocoap.h

@@ -352,6 +352,10 @@ struct _coap_request_ctx {
 #endif
 };
 
+/* forward declarations */
+static inline uint8_t *coap_hdr_data_ptr(const coap_hdr_t *hdr);
+static inline size_t coap_hdr_get_token_len(const coap_hdr_t *hdr);
+
 /**
  * @brief   Get resource path associated with a CoAP request
  *
@@ -548,28 +552,9 @@ static inline unsigned coap_get_id(const coap_pkt_t *pkt)
  */
 static inline unsigned coap_get_token_len(const coap_pkt_t *pkt)
 {
-    uint8_t tkl = pkt->hdr->ver_t_tkl & 0xf;
-
-    if (!IS_USED(MODULE_NANOCOAP_TOKEN_EXT)) {
-        return tkl;
-    }
-
-    void *ext = pkt->hdr + 1;
-    switch (tkl) {
-    case 13:
-        return tkl + *(uint8_t *)ext;
-    case 14:
-        return tkl + 255 + byteorder_bebuftohs(ext);
-    case 15:
-        assert(0);
-        /* fall-through */
-    default:
-        return tkl;
-    }
+    return coap_hdr_get_token_len(pkt->hdr);
 }
 
-static inline uint8_t *coap_hdr_data_ptr(const coap_hdr_t *hdr);
-
 /**
  * @brief   Get pointer to a message's token
  *