From: Ondřej Surý <ondrej@isc.org>
Date: Wed, 1 Dec 2021 16:41:20 +0000 (+0100)
Subject: Improve the logging on failed TCP accept
X-Git-Tag: v9.17.21~6^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=20ac73eb222e60395399b467b0a72015a4dd8845;p=thirdparty%2Fbind9.git

Improve the logging on failed TCP accept

Previously, when TCP accept failed, we have logged a message with
ISC_LOG_ERROR level.  One common case, how this could happen is that the
client hits TCP client quota and is put on hold and when resumed, the
client has already given up and closed the TCP connection.  In such
case, the named would log:

    TCP connection failed: socket is not connected

This message was quite confusing because it actually doesn't say that
it's related to the accepting the TCP connection and also it logs
everything on the ISC_LOG_ERROR level.

Change the log message to "Accepting TCP connection failed" and for
specific error states lower the severity of the log message to
ISC_LOG_INFO.
---

diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index da892b8415a..db5c2471183 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -2034,4 +2034,7 @@ isc__nm_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result, bool async);
 void
 isc__nmsocket_connecttimeout_cb(uv_timer_t *timer);
 
+void
+isc__nm_accept_connection_log(isc_result_t result, bool can_log_quota);
+
 #define STREAM_CLIENTS_PER_CONN 23
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 3404d19ba0e..13168683e11 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -2048,6 +2048,33 @@ isc__nmsocket_connecttimeout_cb(uv_timer_t *timer) {
 	}
 }
 
+void
+isc__nm_accept_connection_log(isc_result_t result, bool can_log_quota) {
+	int level;
+
+	switch (result) {
+	case ISC_R_SUCCESS:
+	case ISC_R_NOCONN:
+		return;
+	case ISC_R_QUOTA:
+	case ISC_R_SOFTQUOTA:
+		if (!can_log_quota) {
+			return;
+		}
+		level = ISC_LOG_INFO;
+		break;
+	case ISC_R_NOTCONNECTED:
+		level = ISC_LOG_INFO;
+		break;
+	default:
+		level = ISC_LOG_ERROR;
+	}
+
+	isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_NETMGR,
+		      level, "Accepting TCP connection failed: %s",
+		      isc_result_totext(result));
+}
+
 static void
 isc__nmsocket_readtimeout_cb(uv_timer_t *timer) {
 	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)timer);
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index 382018944e2..eb6437d8d4a 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -631,15 +631,7 @@ tcp_connection_cb(uv_stream_t *server, int status) {
 
 	result = accept_connection(ssock, quota);
 done:
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tcp_quota()) {
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tcp_quota());
 }
 
 void
@@ -931,15 +923,7 @@ isc__nm_async_tcpaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
 	REQUIRE(sock->tid == isc_nm_tid());
 
 	result = accept_connection(sock, ievent->quota);
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tcp_quota()) {
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tcp_quota());
 }
 
 static isc_result_t
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index 5fed46018f1..9167e52bb5f 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -600,16 +600,7 @@ tcpdns_connection_cb(uv_stream_t *server, int status) {
 
 	result = accept_connection(ssock, quota);
 done:
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tcpdns_quota())
-		{
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tcpdns_quota());
 }
 
 void
@@ -920,16 +911,7 @@ isc__nm_async_tcpdnsaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
 	REQUIRE(ievent->sock->tid == isc_nm_tid());
 
 	result = accept_connection(ievent->sock, ievent->quota);
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tcpdns_quota())
-		{
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tcpdns_quota());
 }
 
 static isc_result_t
diff --git a/lib/isc/netmgr/tlsdns.c b/lib/isc/netmgr/tlsdns.c
index 700874d28e9..137a1709cd2 100644
--- a/lib/isc/netmgr/tlsdns.c
+++ b/lib/isc/netmgr/tlsdns.c
@@ -675,16 +675,7 @@ tlsdns_connection_cb(uv_stream_t *server, int status) {
 
 	result = accept_connection(ssock, quota);
 done:
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tlsdns_quota())
-		{
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tlsdns_quota());
 }
 
 void
@@ -1425,16 +1416,7 @@ isc__nm_async_tlsdnsaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
 	REQUIRE(ievent->sock->tid == isc_nm_tid());
 
 	result = accept_connection(ievent->sock, ievent->quota);
-	if (result != ISC_R_SUCCESS && result != ISC_R_NOCONN) {
-		if ((result != ISC_R_QUOTA && result != ISC_R_SOFTQUOTA) ||
-		    can_log_tlsdns_quota())
-		{
-			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
-				      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
-				      "TCP connection failed: %s",
-				      isc_result_totext(result));
-		}
-	}
+	isc__nm_accept_connection_log(result, can_log_tlsdns_quota());
 }
 
 static isc_result_t