From: Aydın Mercan <aydin@isc.org>
Date: Tue, 2 Jan 2024 13:28:46 +0000 (+0300)
Subject: Expose the TCP client count in statistics channel
X-Git-Tag: v9.19.22~80^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2690dc48d357c85c59f0d72063d7a799e9d03bc0;p=thirdparty%2Fbind9.git

Expose the TCP client count in statistics channel

The statistics channel does not expose the current number of TCP clients
connected, only the highwater. Therefore, users did not have an easy
means to collect statistics about TCP clients served over time. This
information could only be measured as a seperate mechanism via rndc by
looking at the TCP quota filled.

In order to expose the exact current count of connected TCP clients
(tracked by the "tcp-clients" quota) as a statistics counter, an
extra, dedicated Network Manager callback would need to be
implemented for that purpose (a counterpart of ns__client_tcpconn()
that would be run when a TCP connection is torn down), which is
inefficient. Instead, track the number of currently-connected TCP
clients separately for IPv4 and IPv6, as Network Manager statistics.
---

diff --git a/bin/named/statschannel.c b/bin/named/statschannel.c
index 94c97da1e1c..83d420f65f1 100644
--- a/bin/named/statschannel.c
+++ b/bin/named/statschannel.c
@@ -611,6 +611,10 @@ init_desc(void) {
 	SET_SOCKSTATDESC(udp6active, "UDP/IPv6 sockets active", "UDP6Active");
 	SET_SOCKSTATDESC(tcp4active, "TCP/IPv4 sockets active", "TCP4Active");
 	SET_SOCKSTATDESC(tcp6active, "TCP/IPv6 sockets active", "TCP6Active");
+	SET_SOCKSTATDESC(tcp4clients, "TCP/IPv4 clients currently connected",
+			 "TCP4Clients");
+	SET_SOCKSTATDESC(tcp6clients, "TCP/IPv6 clients currently connected",
+			 "TCP6Clients");
 	INSIST(i == isc_sockstatscounter_max);
 
 	/* Initialize DNSSEC statistics */
diff --git a/lib/isc/include/isc/stats.h b/lib/isc/include/isc/stats.h
index 3cc60b06446..23a076eba97 100644
--- a/lib/isc/include/isc/stats.h
+++ b/lib/isc/include/isc/stats.h
@@ -77,6 +77,9 @@ enum {
 	isc_sockstatscounter_tcp4active,
 	isc_sockstatscounter_tcp6active,
 
+	isc_sockstatscounter_tcp4clients,
+	isc_sockstatscounter_tcp6clients,
+
 	isc_sockstatscounter_max,
 };
 
diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index 71822b36411..9363119d3ef 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -386,7 +386,8 @@ typedef enum {
 	STATID_SENDFAIL = 8,
 	STATID_RECVFAIL = 9,
 	STATID_ACTIVE = 10,
-	STATID_MAX = 11,
+	STATID_CLIENTS = 11,
+	STATID_MAX = 12,
 } isc__nm_statid_t;
 
 typedef struct isc_nmsocket_tls_send_req {
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 41541cbb28d..ea1c561a622 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -63,7 +63,8 @@ static const isc_statscounter_t udp4statsindex[] = {
 	-1,
 	isc_sockstatscounter_udp4sendfail,
 	isc_sockstatscounter_udp4recvfail,
-	isc_sockstatscounter_udp4active
+	isc_sockstatscounter_udp4active,
+	-1,
 };
 
 static const isc_statscounter_t udp6statsindex[] = {
@@ -77,7 +78,8 @@ static const isc_statscounter_t udp6statsindex[] = {
 	-1,
 	isc_sockstatscounter_udp6sendfail,
 	isc_sockstatscounter_udp6recvfail,
-	isc_sockstatscounter_udp6active
+	isc_sockstatscounter_udp6active,
+	-1,
 };
 
 static const isc_statscounter_t tcp4statsindex[] = {
@@ -86,7 +88,7 @@ static const isc_statscounter_t tcp4statsindex[] = {
 	isc_sockstatscounter_tcp4connectfail, isc_sockstatscounter_tcp4connect,
 	isc_sockstatscounter_tcp4acceptfail,  isc_sockstatscounter_tcp4accept,
 	isc_sockstatscounter_tcp4sendfail,    isc_sockstatscounter_tcp4recvfail,
-	isc_sockstatscounter_tcp4active
+	isc_sockstatscounter_tcp4active,      isc_sockstatscounter_tcp4clients,
 };
 
 static const isc_statscounter_t tcp6statsindex[] = {
@@ -95,7 +97,7 @@ static const isc_statscounter_t tcp6statsindex[] = {
 	isc_sockstatscounter_tcp6connectfail, isc_sockstatscounter_tcp6connect,
 	isc_sockstatscounter_tcp6acceptfail,  isc_sockstatscounter_tcp6accept,
 	isc_sockstatscounter_tcp6sendfail,    isc_sockstatscounter_tcp6recvfail,
-	isc_sockstatscounter_tcp6active
+	isc_sockstatscounter_tcp6active,      isc_sockstatscounter_tcp6clients,
 };
 
 static void
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index f7fe1a415b8..b6545a912d1 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -855,6 +855,10 @@ accept_connection(isc_nmsocket_t *csock) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
 
+	if (csock->server->pquota != NULL) {
+		isc__nm_incstats(csock, STATID_CLIENTS);
+	}
+
 	/*
 	 * We need to initialize the tcp and timer before failing because
 	 * isc__nm_tcp_close() can't handle uninitalized TCP nmsocket.
@@ -1105,6 +1109,7 @@ tcp_close_sock(isc_nmsocket_t *sock) {
 
 	if (sock->server != NULL) {
 		if (sock->server->pquota != NULL) {
+			isc__nm_decstats(sock, STATID_CLIENTS);
 			isc_quota_release(sock->server->pquota);
 		}
 		isc__nmsocket_detach(&sock->server);