libknot/pkt: extend knot_pkt_get_ext_rcode with TSIG RCODE

src/libknot/packet/pkt.c

@@ -20,6 +20,7 @@
 
 #include "libknot/attribute.h"
 #include "libknot/packet/pkt.h"
+#include "libknot/codes.h"
 #include "libknot/descriptor.h"
 #include "libknot/errcode.h"
 #include "libknot/rrtype/tsig.h"
@@ -860,18 +861,56 @@ int knot_pkt_parse_payload(knot_pkt_t *pkt, unsigned flags)
 }
 
 _public_
-uint16_t knot_pkt_get_ext_rcode(const knot_pkt_t *pkt)
+uint16_t knot_pkt_ext_rcode(const knot_pkt_t *pkt)
 {
 	if (pkt == NULL) {
 		return 0;
 	}
 
-	uint8_t rcode = knot_wire_get_rcode(pkt->wire);
+	/* Get header RCODE. */
+	uint16_t rcode = knot_wire_get_rcode(pkt->wire);
 
-	if (pkt->opt_rr) {
+	/* Update to extended RCODE if EDNS is available. */
+	if (pkt->opt_rr != NULL) {
 		uint8_t opt_rcode = knot_edns_get_ext_rcode(pkt->opt_rr);
-		return knot_edns_whole_rcode(opt_rcode, rcode);
+		rcode = knot_edns_whole_rcode(opt_rcode, rcode);
+	}
+
+	/* Return if not NOTAUTH. */
+	if (rcode != KNOT_RCODE_NOTAUTH) {
+		return rcode;
+	}
+
+	/* Get TSIG RCODE. */
+	uint16_t tsig_rcode = KNOT_RCODE_NOERROR;
+	if (pkt->tsig_rr != NULL) {
+		tsig_rcode = knot_tsig_rdata_error(pkt->tsig_rr);
+	}
+
+	/* Return proper RCODE. */
+	if (tsig_rcode != KNOT_RCODE_NOERROR) {
+		return tsig_rcode;
 	} else {
 		return rcode;
 	}
 }
+
+_public_
+const char *knot_pkt_ext_rcode_name(const knot_pkt_t *pkt)
+{
+	if (pkt == NULL) {
+		return "";
+	}
+
+	uint16_t rcode = knot_pkt_ext_rcode(pkt);
+
+	const knot_lookup_t *item = NULL;
+	if (pkt->tsig_rr != NULL) {
+		item = knot_lookup_by_id(knot_tsig_rcode_names, rcode);
+	}
+	if (item == NULL) {
+		item = knot_lookup_by_id(knot_rcode_names, rcode);
+	}
+
+	return (item != NULL) ? item->name : "";
+}

src/libknot/packet/pkt.h

@@ -316,17 +316,27 @@ int knot_pkt_parse_section(knot_pkt_t *pkt, unsigned flags);
 int knot_pkt_parse_payload(knot_pkt_t *pkt, unsigned flags);
 
 /*!
- * \brief Get the Extended RCODE from the packet.
+ * \brief Get packet extended RCODE.
  *
- * Extended RCODE is created by using the Extended RCODE field from OPT RR as
- * higher 8 bits and the RCODE from DNS Header as the lower 4 bits, resulting
- * in a 12-bit unsigned integer. (See RFC 6891, Section 6.1.3).
+ * Extended RCODE is created by considering TSIG RCODE, EDNS RCODE and
+ * DNS Header RCODE. (See RFC 6895, Section 2.3).
  *
  * \param pkt Packet to get the response code from.
  *
  * \return Whole extended RCODE (0 if pkt == NULL).
  */
-uint16_t knot_pkt_get_ext_rcode(const knot_pkt_t *pkt);
+uint16_t knot_pkt_ext_rcode(const knot_pkt_t *pkt);
+
+/*!
+ * \brief Get packet extended RCODE name.
+ *
+ * The packet parameter is important as the name depends on TSIG.
+ *
+ * \param pkt Packet to get the response code from.
+ *
+ * \return RCODE name (or empty string if not known).
+ */
+const char *knot_pkt_ext_rcode_name(const knot_pkt_t *pkt);
 
 /*!
  * \brief Checks if there is an OPT RR in the packet.