From 1ba4ae28303b90ebd14b2dd9cda7a01f79e370ee Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Mon, 12 Sep 2022 14:50:17 +0100
Subject: [PATCH] Add stale cache replies to metrics.

---
 src/cache.c   | 2 ++
 src/forward.c | 2 +-
 src/metrics.c | 1 +
 src/metrics.h | 1 +
 4 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/cache.c b/src/cache.c
index 404147b..dde4580 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -1729,6 +1729,8 @@ void dump_cache(time_t now)
 	    daemon->cachesize, daemon->metrics[METRIC_DNS_CACHE_LIVE_FREED], daemon->metrics[METRIC_DNS_CACHE_INSERTED]);
   my_syslog(LOG_INFO, _("queries forwarded %u, queries answered locally %u"), 
 	    daemon->metrics[METRIC_DNS_QUERIES_FORWARDED], daemon->metrics[METRIC_DNS_LOCAL_ANSWERED]);
+  if (option_bool(OPT_STALE_CACHE))
+    my_syslog(LOG_INFO, _("queries answered from stale cache %u"), daemon->metrics[METRIC_DNS_STALE_ANSWERED]);
 #ifdef HAVE_AUTH
   my_syslog(LOG_INFO, _("queries for authoritative zones %u"), daemon->metrics[METRIC_DNS_AUTH_ANSWERED]);
 #endif
diff --git a/src/forward.c b/src/forward.c
index f2dbbc1..f1d8f7d 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -1799,7 +1799,7 @@ void receive_query(struct listener *listen, time_t now)
 #endif
 	  send_from(listen->fd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND),
 		    (char *)header, m, &source_addr, &dst_addr, if_index);
-	  daemon->metrics[METRIC_DNS_LOCAL_ANSWERED]++;
+	  daemon->metrics[stale ? METRIC_DNS_STALE_ANSWERED : METRIC_DNS_LOCAL_ANSWERED]++;
 	}
       
       if (m == 0 || stale)
diff --git a/src/metrics.c b/src/metrics.c
index 6873529..eeea074 100644
--- a/src/metrics.c
+++ b/src/metrics.c
@@ -22,6 +22,7 @@ const char * metric_names[] = {
     "dns_queries_forwarded",
     "dns_auth_answered",
     "dns_local_answered",
+    "dns_stale_answered",
     "bootp",
     "pxe",
     "dhcp_ack",
diff --git a/src/metrics.h b/src/metrics.h
index df72ec6..f7c817b 100644
--- a/src/metrics.h
+++ b/src/metrics.h
@@ -21,6 +21,7 @@ enum {
   METRIC_DNS_QUERIES_FORWARDED,
   METRIC_DNS_AUTH_ANSWERED,
   METRIC_DNS_LOCAL_ANSWERED,
+  METRIC_DNS_STALE_ANSWERED,
   METRIC_BOOTP,
   METRIC_PXE,
   METRIC_DHCPACK,