Merge pull request #13543 from omoerbeek/rec-aggr-nsec3-empty

rec: a single NSEC3 record covering everything is a special case
PowerDNS · Dec 1, 2023 · a9fec78 · a9fec78
2 parents 099d31d + 3f6fb38
commit a9fec78
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diff --git a/pdns/recursordist/aggressive_nsec.cc b/pdns/recursordist/aggressive_nsec.cc
@@ -261,6 +261,10 @@ static bool commonPrefixIsLong(const string& one, const string& two, size_t boun
 bool AggressiveNSECCache::isSmallCoveringNSEC3(const DNSName& owner, const std::string& nextHash)
 {
   std::string ownerHash(fromBase32Hex(owner.getRawLabel(0)));
+  // Special case: empty zone, so the single NSEC3 covers everything. Prefix is long but we still want it cached.
+  if (ownerHash == nextHash) {
+    return false;
+  }
   return commonPrefixIsLong(ownerHash, nextHash, AggressiveNSECCache::s_maxNSEC3CommonPrefix);
 }
 

diff --git a/pdns/recursordist/test-aggressive_nsec_cc.cc b/pdns/recursordist/test-aggressive_nsec_cc.cc
@@ -21,6 +21,9 @@ BOOST_AUTO_TEST_CASE(test_small_coverering_nsec3)
     {"0ujhshp2lhmnpoo9qde4blg4gq3hgl99", "7ujhshp2lhmnpoo9qde4blg4gq3hgl9a", 2, false},
     {"0ujhshp2lhmnpoo9qde4blg4gq3hgl99", "fujhshp2lhmnpoo9qde4blg4gq3hgl9a", 1, false},
     {"0ujhshp2lhmnpoo9qde4blg4gq3hgl99", "8ujhshp2lhmnpoo9qde4blg4gq3hgl9a", 1, false},
+    {"8ujhshp2lhmnpoo9qde4blg4gq3hgl99", "8ujhshp2lhmnpoo9qde4blg4gq3hgl99", 0, false},
+    {"8ujhshp2lhmnpoo9qde4blg4gq3hgl99", "8ujhshp2lhmnpoo9qde4blg4gq3hgl99", 1, false},
+    {"8ujhshp2lhmnpoo9qde4blg4gq3hgl99", "8ujhshp2lhmnpoo9qde4blg4gq3hgl99", 157, false},
   };
 
   for (const auto& [owner, next, boundary, result] : table) {