From ca0831d9a14c409c631b0ee49d6fdba6b2239b6f Mon Sep 17 00:00:00 2001
From: Peter van Dijk <peter.van.dijk@powerdns.com>
Date: Tue, 31 Jan 2023 10:48:27 +0100
Subject: [PATCH] ixfrdist /metrics: add unknown domain in-query counter

---
 pdns/ixfrdist-stats.cc                  | 4 ++++
 pdns/ixfrdist-stats.hh                  | 4 ++++
 pdns/ixfrdist.cc                        | 1 +
 regression-tests.ixfrdist/test_Stats.py | 2 +-
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pdns/ixfrdist-stats.cc b/pdns/ixfrdist-stats.cc
index 292565a819..bb4dd8ba59 100644
--- a/pdns/ixfrdist-stats.cc
+++ b/pdns/ixfrdist-stats.cc
@@ -97,5 +97,9 @@ std::string ixfrdistStats::getStats() {
     helpAdded = true;
   }
 
+  stats<<"# HELP "<<prefix<<"unknown_domain_inqueries_total Number of queries received for domains unknown to us"<<std::endl;
+  stats<<"# TYPE "<<prefix<<"unknown_domain_inqueries_total counter"<<std::endl;
+  stats<<prefix<<"unknown_domain_inqueries_total "<<progStats.unknownDomainInQueries<<std::endl;
+
   return stats.str();
 }
diff --git a/pdns/ixfrdist-stats.hh b/pdns/ixfrdist-stats.hh
index addfe06003..26a27be60f 100644
--- a/pdns/ixfrdist-stats.hh
+++ b/pdns/ixfrdist-stats.hh
@@ -64,6 +64,9 @@ class ixfrdistStats {
     void registerDomain(const DNSName& d) {
       domainStats[d].haveZone = false;
     }
+    void incrementUnknownDomainInQueries(const DNSName &d) { // the name is ignored. It would be great to report it, but we don't want to blow up Prometheus
+      progStats.unknownDomainInQueries += 1;
+    }
   private:
     class perDomainStat {
       public:
@@ -83,6 +86,7 @@ class ixfrdistStats {
     class programStats {
       public:
         time_t startTime;
+        std::atomic<uint32_t> unknownDomainInQueries;
     };
 
     std::map<DNSName, perDomainStat> domainStats;
diff --git a/pdns/ixfrdist.cc b/pdns/ixfrdist.cc
index 24ac0e6a3a..997fdf9012 100644
--- a/pdns/ixfrdist.cc
+++ b/pdns/ixfrdist.cc
@@ -818,6 +818,7 @@ static void handleUDPRequest(int fd, boost::any&) {
     g_stats.incrementSOAinQueries(mdp.d_qname); // FIXME: this also counts IXFR queries (but the response is the same as to a SOA query)
     makeSOAPacket(mdp, packet);
   } else {
+    g_stats.incrementUnknownDomainInQueries(mdp.d_qname);
     makeRefusedPacket(mdp, packet);
   }
 
diff --git a/regression-tests.ixfrdist/test_Stats.py b/regression-tests.ixfrdist/test_Stats.py
index 8c76511add..61b272bacd 100644
--- a/regression-tests.ixfrdist/test_Stats.py
+++ b/regression-tests.ixfrdist/test_Stats.py
@@ -29,7 +29,7 @@ webserver-address: %s
 
     _config_domains = {'example': '127.0.0.1:' + str(xfrServerPort)}
 
-    metric_prog_stats = ["ixfrdist_uptime_seconds", "ixfrdist_domains"]
+    metric_prog_stats = ["ixfrdist_uptime_seconds", "ixfrdist_domains", "ixfrdist_unknown_domain_inqueries_total"]
     metric_domain_stats = ["ixfrdist_soa_serial", "ixfrdist_soa_checks_total",
                            "ixfrdist_soa_checks_failed_total",
                            "ixfrdist_soa_inqueries_total",
-- 
2.47.2