lib/resolve: store auth addr/rtt in consume() layer

during the consume step, the information about
upstream authoritative (address and current rtt)
is exposed in the request structure, just like
information about current query

daemon/lua/kres.lua

@@ -213,6 +213,10 @@ struct kr_request {
 		const knot_rrset_t *key;
 		const struct sockaddr *addr;
 	} qsource;
+	struct {
+	    unsigned rtt;
+	    const struct sockaddr *addr;
+	} upstream;
 	uint32_t options;
 	int state;
 	rr_array_t authority;

lib/resolve.c

@@ -445,7 +445,19 @@ int kr_resolve_consume(struct kr_request *request, const struct sockaddr *src, k
 			randomized_qname_case(qname_raw, qry->secret);
 		}
 		request->state = KNOT_STATE_CONSUME;
-		ITERATE_LAYERS(request, qry, consume, packet);
+		if (qry->flags & QUERY_CACHED) {
+			ITERATE_LAYERS(request, qry, consume, packet);
+		} else {
+			struct timeval now;
+			gettimeofday(&now, NULL);
+			/* Fill in source and latency information. */
+			request->upstream.rtt = time_diff(&qry->timestamp, &now);
+			request->upstream.addr = src;
+			ITERATE_LAYERS(request, qry, consume, packet);
+			/* Clear temporary information */
+			request->upstream.addr = NULL;
+			request->upstream.rtt = 0;
+		}
 	}
 
 	/* Track RTT for iterative answers */

lib/resolve.h

@@ -113,6 +113,10 @@ struct kr_request {
         const knot_rrset_t *key;
         const struct sockaddr *addr;
     } qsource;
+    struct {
+        unsigned rtt;                  /**< Current upstream RTT */
+        const struct sockaddr *addr;   /**< Current upstream address */
+    } upstream;                        /**< Upstream information, valid only in consume() phase */
     uint32_t options;
     int state;
     rr_array_t authority;