From: Marek Vavruša <marek.vavrusa@nic.cz>
Date: Sat, 18 Jul 2015 22:55:48 +0000 (+0200)
Subject: layer/rrcache: minttl 5s default
X-Git-Tag: v1.0.0-beta1~72^2~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71f20c5663bb37a6c128c468d6a5118c0b3696a5;p=thirdparty%2Fknot-resolver.git

layer/rrcache: minttl 5s default
---

diff --git a/lib/layer/rrcache.c b/lib/layer/rrcache.c
index adc77a8ab..65b0596a5 100644
--- a/lib/layer/rrcache.c
+++ b/lib/layer/rrcache.c
@@ -26,6 +26,7 @@
 #include "lib/module.h"
 
 #define DEBUG_MSG(fmt...) QRDEBUG(kr_rplan_current(rplan), " rc ",  fmt)
+#define DEFAULT_MINTTL (5) /* Short-time "no data" retention to avoid bursts */
 
 static int begin(knot_layer_t *ctx, void *module_param)
 {
@@ -125,15 +126,22 @@ struct stash_baton
 {
 	struct kr_cache_txn *txn;
 	unsigned timestamp;
+	uint32_t min_ttl;
 };
 
 static int commit_rr(const char *key, void *val, void *data)
 {
 	knot_rrset_t *rr = val;
 	struct stash_baton *baton = data;
-	if (knot_rrset_ttl(rr) < 1) {
-		return kr_ok(); /* Ignore cache busters */
+	/* Ensure minimum TTL */
+	knot_rdata_t *rd = rr->rrs.data;
+	for (uint16_t i = 0; i < rr->rrs.rr_count; ++i) {
+		if (knot_rdata_ttl(rd) < baton->min_ttl) {
+			knot_rdata_set_ttl(rd, baton->min_ttl);
+		}
+		rd = kr_rdataset_next(rd);
 	}
+
 	/* Check if already cached */
 	/** @todo This should check if less trusted data is in the cache,
 	          for that the cache would need to trace data trust level.
@@ -154,7 +162,8 @@ static int stash_commit(map_t *stash, unsigned timestamp, struct kr_cache_txn *t
 {
 	struct stash_baton baton = {
 		.txn = txn,
-		.timestamp = timestamp
+		.timestamp = timestamp,
+		.min_ttl = DEFAULT_MINTTL
 	};
 	return map_walk(stash, &commit_rr, &baton);
 }