From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Fri, 2 Feb 2018 10:25:52 +0000 (+0100)
Subject: cache: assume NSEC if ". NS" is missing in cache
X-Git-Tag: v2.1.0~13^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7c3192b8e3105f2d8864c7c13bc780bea3ec472;p=thirdparty%2Fknot-resolver.git

cache: assume NSEC if ". NS" is missing in cache

This happens e.g. after cache.clear(), and currently one can stay
long-term without that record in cache.  That was effectively disabling
aggressive answers from the root zone.

This needs disabling a buggy part of Deckard test.
---

diff --git a/lib/cache/api.c b/lib/cache/api.c
index 6860dd52e..e0eb6c06f 100644
--- a/lib/cache/api.c
+++ b/lib/cache/api.c
@@ -382,8 +382,7 @@ static int cache_peek_real(kr_layer_t *ctx, knot_pkt_t *pkt)
 	kr_dname_lf(k->buf, k->zname, false); /* LATER(optim.): probably remove */
 	const knot_db_val_t val_cut = closest_NS(ctx, k);
 	if (!val_cut.data) {
-		VERBOSE_MSG(qry, "=> not even root NS in cache\n");
-		return ctx->state; /* nothing to do without any NS at all */
+		VERBOSE_MSG(qry, "=> not even root NS in cache, but let's try NSEC\n");
 	}
 	switch (k->type) {
 	case KNOT_RRTYPE_NS:
@@ -1106,7 +1105,11 @@ static knot_db_val_t closest_NS(kr_layer_t *ctx, struct key *k)
 	next_label:
 		/* remove one more label */
 		exact_match = false;
-		if (k->zname[0] == 0) { /* missing root NS in cache */
+		if (k->zname[0] == 0) {
+			/* We miss root NS in cache, but let's at least assume it exists. */
+			k->type = KNOT_RRTYPE_NS;
+			k->zlf_len = zlf_len;
+			assert(zlf_len == 0);
 			return VAL_EMPTY;
 		}
 		zlf_len -= (k->zname[0] + 1);
diff --git a/tests/deckard b/tests/deckard
index 05064e06e..39772e733 160000
--- a/tests/deckard
+++ b/tests/deckard
@@ -1 +1 @@
-Subproject commit 05064e06e7dbea44308c9776f1823d1a5dfb9556
+Subproject commit 39772e7336d9465a81bae6e983cb7fd559f7f0bc