From c340d2097dd2c35ac9ab48ddce6b3f0b4c55795d Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 15 Jan 2021 12:01:30 +0100
Subject: [PATCH] dnsdist: More tests for the dynamic block's sliding window

Check that we do not look at queries older than our sliding window,
but also that we correctly trigger a block with a huge peak of
queries not followed by any more queries.
---
 pdns/dnsdistdist/test-dnsdistdynblocks_hh.cc | 59 +++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/pdns/dnsdistdist/test-dnsdistdynblocks_hh.cc b/pdns/dnsdistdist/test-dnsdistdynblocks_hh.cc
index 6de07d5ff9..7bbdd02c3e 100644
--- a/pdns/dnsdistdist/test-dnsdistdynblocks_hh.cc
+++ b/pdns/dnsdistdist/test-dnsdistdynblocks_hh.cc
@@ -58,7 +58,7 @@ BOOST_AUTO_TEST_CASE(test_DynBlockRulesGroup_QueryRate) {
   {
     /* insert just above 50 qps from a given client in the last 10s
        this should trigger the rule this time */
-    size_t numberOfQueries = 50 * numberOfSeconds + 1;
+    size_t numberOfQueries = (50 * numberOfSeconds) + 1;
     g_rings.clear();
     BOOST_CHECK_EQUAL(g_rings.getNumberOfQueryEntries(), 0U);
     g_dynblockNMG.setState(emptyNMG);
@@ -81,6 +81,63 @@ BOOST_AUTO_TEST_CASE(test_DynBlockRulesGroup_QueryRate) {
     BOOST_CHECK_EQUAL(block.warning, false);
   }
 
+  {
+    /* clear the rings and dynamic blocks */
+    g_rings.clear();
+    BOOST_CHECK_EQUAL(g_rings.getNumberOfQueryEntries(), 0U);
+    g_dynblockNMG.setState(emptyNMG);
+
+    /* Insert 100 qps from a given client in the last 10s
+       this should trigger the rule */
+    size_t numberOfQueries = 100;
+
+    for (size_t timeIdx = 0; timeIdx < numberOfSeconds; timeIdx++) {
+      for (size_t idx = 0; idx < numberOfQueries; idx++) {
+        struct timespec when = now;
+        when.tv_sec -= (9 - timeIdx);
+        g_rings.insertQuery(when, requestor1, qname, qtype, size, dh);
+      }
+    }
+    BOOST_CHECK_EQUAL(g_rings.getNumberOfQueryEntries(), numberOfQueries * numberOfSeconds);
+
+    dbrg.apply(now);
+    BOOST_CHECK_EQUAL(g_dynblockNMG.getLocal()->size(), 1U);
+
+    /* now we clean up the dynamic blocks, simulating an admin removing the block */
+    g_dynblockNMG.setState(emptyNMG);
+    /* we apply the rules again, but as if we were 20s in the future.
+       Since we have a time windows of 10s nothing should be added,
+       regardless of the number of queries
+    */
+    struct timespec later = now;
+    later.tv_sec += 20;
+    dbrg.apply(later);
+    BOOST_CHECK_EQUAL(g_dynblockNMG.getLocal()->size(), 0U);
+
+    /* just in case */
+    g_dynblockNMG.setState(emptyNMG);
+
+    /* we apply the rules again, this tile as if we were 5s in the future.
+       Since we have a time windows of 10s, and 100 qps over 5s then 0 qps over 5s
+       is more than 50qps over 10s, the block should be added
+    */
+    later = now;
+    later.tv_sec += 5;
+    dbrg.apply(later);
+    BOOST_CHECK_EQUAL(g_dynblockNMG.getLocal()->size(), 1U);
+
+    /* clean up */
+    g_dynblockNMG.setState(emptyNMG);
+
+    /* we apply the rules again, this tile as if we were 6s in the future.
+       Since we have a time windows of 10s, and 100 qps over 4s then 0 qps over 6s
+       is LESS than 50qps over 10s, the block should NOT be added
+    */
+    later = now;
+    later.tv_sec += 6;
+    dbrg.apply(later);
+    BOOST_CHECK_EQUAL(g_dynblockNMG.getLocal()->size(), 0U);
+}
 }
 
 BOOST_AUTO_TEST_CASE(test_DynBlockRulesGroup_QTypeRate) {
-- 
2.47.2