libknot/pkt: return KNOT_ETRAIL instead of KNOT_EMAILF if trailing data

src/libknot/errcode.h

@@ -156,6 +156,8 @@ enum knot_error {
 	KNOT_NO_PUBLIC_KEY,
 	KNOT_NO_PRIVATE_KEY,
 
+	KNOT_ETRAIL,
+
 	KNOT_ERROR_MAX = -501
 };
 

src/libknot/error.c

@@ -156,6 +156,8 @@ static const struct error errors[] = {
 	{ KNOT_NO_PUBLIC_KEY,         "no public key" },
 	{ KNOT_NO_PRIVATE_KEY,        "no private key" },
 
+	{ KNOT_ETRAIL,                "trailing data" },
+
 	{ KNOT_ERROR, NULL } /* Terminator */
 };
 

src/libknot/packet/pkt.c

@@ -852,7 +852,7 @@ int knot_pkt_parse_payload(knot_pkt_t *pkt, unsigned flags)
 
 	/* Check for trailing garbage. */
 	if (pkt->parsed < pkt->size) {
-		return KNOT_EMALF;
+		return KNOT_ETRAIL;
 	}
 
 	return KNOT_EOK;

src/libknot/packet/pkt.h

@@ -245,7 +245,9 @@ uint16_t knot_pkt_rr_offset(const knot_pktsection_t *section, uint16_t i);
  *
  * \param pkt Given packet.
  * \param flags Parsing flags (allowed KNOT_PF_KEEPWIRE)
- * \return KNOT_EOK, KNOT_EMALF and other errors
+ * \retval KNOT_EOK if success.
+ * \retval KNOT_ETRAIL if success but with some trailing data.
+ * \retval KNOT_EMALF and other errors.
  */
 int knot_pkt_parse(knot_pkt_t *pkt, unsigned flags);