Commit 8068d117 authored by Marek Vavruša's avatar Marek Vavruša Committed by Marek Vavruša

lib/nsrep: lower bound on rtt, optional throttling

when a NS is in the TIMEOUT, it can’t be autoselected by default but only probed after a successful dice roll - however in some scenarios we’d like to probe timeouting servers more thoroughly 
parent 0c26f792
......@@ -21,6 +21,7 @@
#include <libknot/internal/sockaddr.h>
#include "lib/nsrep.h"
#include "lib/rplan.h"
#include "lib/defines.h"
#include "lib/generic/pack.h"
......@@ -97,7 +98,7 @@ static int eval_nsrep(const char *k, void *v, void *baton)
* The fastest NS is preferred by workers until it is depleted (timeouts or degrades),
* at the same time long distance scouts probe other sources (low probability).
* Servers on TIMEOUT (depleted) can be probed by the dice roll only */
if (score < ns->score && score < KR_NS_TIMEOUT) {
if (score < ns->score && (ns->flags & QUERY_NO_THROTTLE || score < KR_NS_TIMEOUT)) {
update_nsrep(ns, (const knot_dname_t *)k, addr, score);
} else {
/* With 5% chance, probe server with a probability given by its RTT / MAX_RTT */
......@@ -135,6 +136,9 @@ int kr_nsrep_update(struct kr_nsrep *ns, unsigned score, kr_nsrep_lru_t *repcach
if (score > KR_NS_MAX_SCORE) {
score = KR_NS_MAX_SCORE;
}
if (score <= KR_NS_UNKNOWN) {
score = KR_NS_UNKNOWN + 1;
}
/* Set initial value or smooth over last two measurements */
if (*cur != 0) {
*cur = (*cur + score) / 2;
......
......@@ -46,6 +46,7 @@ typedef lru_hash(unsigned) kr_nsrep_lru_t;
struct kr_nsrep
{
unsigned score; /**< Server score */
unsigned flags; /**< Server flags */
const knot_dname_t *name; /**< Server name */
kr_nsrep_lru_t *repcache; /**< Reputation cache pointer */
union {
......
......@@ -431,6 +431,11 @@ int kr_resolve_produce(struct kr_request *request, struct sockaddr **dst, int *t
ns_election:
/* Elect best nameserver candidate */
assert(++ns_election_iter < KR_ITER_LIMIT);
/* Set slow NS throttling mode */
qry->ns.flags = 0;
if (qry->flags & QUERY_NO_THROTTLE) {
qry->ns.flags = QUERY_NO_THROTTLE;
}
kr_nsrep_elect(&qry->ns, &qry->zone_cut.nsset, request->ctx->nsrep);
if (qry->ns.score > KR_NS_MAX_SCORE) {
DEBUG_MSG("=> no valid NS left\n");
......
......@@ -29,13 +29,14 @@
/** Query flags */
enum kr_query_flag {
QUERY_NO_MINIMIZE = 1 << 0, /**< Don't minimize QNAME. */
QUERY_TCP = 1 << 1, /**< Use TCP for this query. */
QUERY_RESOLVED = 1 << 2, /**< Query is resolved. */
QUERY_AWAIT_IPV4 = 1 << 3, /**< Query is waiting for A address. */
QUERY_AWAIT_IPV6 = 1 << 4, /**< Query is waiting for AAAA address. */
QUERY_AWAIT_CUT = 1 << 5, /**< Query is waiting for zone cut lookup */
QUERY_SAFEMODE = 1 << 6, /**< Don't use fancy stuff (EDNS...) */
QUERY_CACHED = 1 << 7 /**< Query response is cached. */
QUERY_NO_THROTTLE = 1 << 1, /**< No query/slow NS throttling. */
QUERY_TCP = 1 << 2, /**< Use TCP for this query. */
QUERY_RESOLVED = 1 << 3, /**< Query is resolved. */
QUERY_AWAIT_IPV4 = 1 << 4, /**< Query is waiting for A address. */
QUERY_AWAIT_IPV6 = 1 << 5, /**< Query is waiting for AAAA address. */
QUERY_AWAIT_CUT = 1 << 6, /**< Query is waiting for zone cut lookup */
QUERY_SAFEMODE = 1 << 7, /**< Don't use fancy stuff (EDNS...) */
QUERY_CACHED = 1 << 8 /**< Query response is cached. */
};
/**
......
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