daemon: track case when all upstreams fail

previously full timeout led to reset of the evaluated
address list and no upstream server was penalised
for not answering the query, this penalises all of
tried servers with TIMEOUT

daemon/worker.c

@@ -26,6 +26,7 @@
 #endif
 #include <assert.h>
 #include "lib/utils.h"
+#include "lib/layer.h"
 #include "daemon/worker.h"
 #include "daemon/engine.h"
 #include "daemon/io.h"
@@ -350,11 +351,28 @@ static void on_timeout(uv_timer_t *req)
 	knot_rrtype_to_string(knot_pkt_qtype(task->pktbuf), type_str, sizeof(type_str));
 	DEBUG_MSG("ioreq timeout %s %s %p\n", qname_str, type_str, req);
 #endif
-	if (!uv_is_closing(handle)) {
-		struct worker_ctx *worker = task->worker;
-		worker->stats.timeout += 1;
-		qr_task_step(task, NULL, NULL);
+	/* Ignore if this timeout is being terminated. */
+	if (uv_is_closing(handle)) {
+		return;
+	}
+	/* Penalize all tried nameservers with a timeout. */
+	struct worker_ctx *worker = task->worker;
+	if (task->leading && task->pending_count > 0) {
+		struct kr_query *qry = array_tail(task->req.rplan.pending);
+		struct sockaddr_in6 *addrlist = (struct sockaddr_in6 *)task->addrlist;
+		for (uint16_t i = 0; i < MIN(task->pending_count, task->addrlist_count); ++i) {
+			struct sockaddr *choice = (struct sockaddr *)(&addrlist[i]);
+			WITH_DEBUG {
+				char addr_str[INET6_ADDRSTRLEN];
+				inet_ntop(choice->sa_family, kr_inaddr(choice), addr_str, sizeof(addr_str));
+				QRDEBUG(qry, "wrkr", "=> server: '%s' flagged as 'bad'\n", addr_str);
+			}
+			kr_nsrep_update_rtt(&qry->ns, choice, KR_NS_TIMEOUT, worker->engine->resolver.cache_rtt);
+		}
 	}
+	/* Interrupt current pending request. */
+	worker->stats.timeout += 1;
+	qr_task_step(task, NULL, NULL);
 }
 
 /* This is called when we send subrequest / answer */