Added TCP high-water statistics variable

This variable will report the maximum number of simultaneous tcp clients
that BIND has served while running.

It can be verified by running rndc status, then inspect "tcp high-water:
count", or by generating statistics file, rndc stats, then inspect the
line with "TCP connection high-water" text.

The tcp-highwater variable is atomically updated based on an existing
tcp-quota system handled in ns/client.c.

(cherry picked from commit 66fe8627de2c8488b7808c7b342e6ceb51f65414)

diff --git a/bin/named/server.c b/bin/named/server.c
index 86d4eb82508351edfe66ba6dc0e8c0aa2f1d004f..6e54dcaeb42ed3d0cf97b3bcea934cfad1c046c9 100644 (file)
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -11583,6 +11583,11 @@ named_server_status(named_server_t *server, isc_buffer_t **text) {
                     isc_quota_getmax(&server->sctx->tcpquota));
        CHECK(putstr(text, line));
 
+       snprintf(line, sizeof(line), "TCP high-water: %u\n",
+                    (unsigned)ns_stats_get_counter(server->sctx->nsstats,
+                                         ns_statscounter_tcphighwater));
+       CHECK(putstr(text, line));
+
        if (server->reload_in_progress) {
                CHECK(putstr(text, "reload/reconfig in progress"));
        }

diff --git a/bin/named/statschannel.c b/bin/named/statschannel.c
index b32d72f6d9efa3759184ce32bc0ba6e66f57fd8b..abaeed5e8ed697e10cfb0b2e557f1f10c55566dd 100644 (file)
--- a/bin/named/statschannel.c
+++ b/bin/named/statschannel.c
@@ -234,6 +234,8 @@ init_desc(void) {
        SET_NSSTATDESC(invalidsig, "requests with invalid signature",
                       "ReqBadSIG");
        SET_NSSTATDESC(requesttcp, "TCP requests received", "ReqTCP");
+       SET_NSSTATDESC(tcphighwater, "TCP connection high-water",
+                      "TCPConnHighWater");
        SET_NSSTATDESC(authrej, "auth queries rejected", "AuthQryRej");
        SET_NSSTATDESC(recurserej, "recursive queries rejected", "RecQryRej");
        SET_NSSTATDESC(xfrrej, "transfer requests rejected", "XfrRej");
@@ -315,6 +317,7 @@ init_desc(void) {
                       "QryUsedStale");
        SET_NSSTATDESC(prefetch, "queries triggered prefetch", "Prefetch");
        SET_NSSTATDESC(keytagopt, "Keytag option received", "KeyTagOpt");
+
        INSIST(i == ns_statscounter_max);
 
        /* Initialize resolver statistics */

diff --git a/lib/ns/client.c b/lib/ns/client.c
index e84a3c853cdf5d2d027445039b881a2270eb42f0..22a0cb662890c4253db4b67dfd5aa3b2dd69c0c9 100644 (file)
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -3465,7 +3465,6 @@ client_accept(ns_client_t *client) {
        isc_result_t result;
 
        CTRACE("accept");
-
        /*
         * Set up a new TCP connection. This means try to attach to the
         * TCP client quota (tcp-clients), but fail if we're over quota.
@@ -3516,6 +3515,12 @@ client_accept(ns_client_t *client) {
                RUNTIME_CHECK(result == ISC_R_SUCCESS);
        }
 
+       /* TCP high-water stats update. */
+       unsigned int curr_tcpquota = isc_quota_getused(&client->sctx->tcpquota);
+       ns_stats_update_if_greater(client->sctx->nsstats,
+                                  ns_statscounter_tcphighwater,
+                                  curr_tcpquota);
+
        /*
         * If this client was set up using get_client() or get_worker(),
         * then TCP is already marked active. However, if it was restarted

diff --git a/lib/ns/include/ns/stats.h b/lib/ns/include/ns/stats.h
index f456a971b0a2b112b329dc45071e98aea31c544a..175813113ebffa3ff6f5f797499c533e044869cf 100644 (file)
--- a/lib/ns/include/ns/stats.h
+++ b/lib/ns/include/ns/stats.h
@@ -102,7 +102,9 @@ enum {
        ns_statscounter_prefetch = 63,
        ns_statscounter_keytagopt = 64,
 
-       ns_statscounter_max = 65
+       ns_statscounter_tcphighwater = 65,
+
+       ns_statscounter_max = 66,
 };
 
 void