From: Ondřej Surý <ondrej@isc.org>
Date: Thu, 24 Nov 2022 16:11:22 +0000 (+0100)
Subject: Make the netmgr send callback to be asynchronous only when needed
X-Git-Tag: v9.19.8~42^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3004da3a5ce577c0e794606fd32f1b99d830525;p=thirdparty%2Fbind9.git

Make the netmgr send callback to be asynchronous only when needed

Previously, the send callback would be synchronous only on success.  Add
an option (similar to what other callbacks have) to decide whether we
need the asynchronous send callback on a higher level.

On a general level, we need the asynchronous callbacks to happen only
when we are invoking the callback from the public API.  If the path to
the callback went through the libuv callback or netmgr callback, we are
already on asynchronous path, and there's no need to make the call to
the callback asynchronous again.

For the send callback, this means we need the asynchronous path for
failure paths inside the isc_nm_send() (which calls isc__nm_udp_send(),
isc__nm_tcp_send(), etc...) - all other invocations of the send callback
could be synchronous, because those are called from the respective libuv
send callbacks.
---

diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index d17c18d81ba..4271990bffd 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -1946,7 +1946,7 @@ isc__nm_alloc_dnsbuf(isc_nmsocket_t *sock, size_t len);
 
 void
 isc__nm_failed_send_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
-		       isc_result_t eresult);
+		       isc_result_t eresult, bool async);
 void
 isc__nm_failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult);
 void
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 7583e531f5a..f2b4127cf2a 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -1324,12 +1324,12 @@ isc__nm_alloc_dnsbuf(isc_nmsocket_t *sock, size_t len) {
 
 void
 isc__nm_failed_send_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
-		       isc_result_t eresult) {
+		       isc_result_t eresult, bool async) {
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(VALID_UVREQ(req));
 
 	if (req->cb.send != NULL) {
-		isc__nm_sendcb(sock, req, eresult, true);
+		isc__nm_sendcb(sock, req, eresult, async);
 	} else {
 		isc__nm_uvreq_put(&req, sock);
 	}
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index 9b2e9380035..239a24fb5a7 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -1029,7 +1029,7 @@ isc__nm_tcp_send(isc_nmhandle_t *handle, const isc_region_t *region,
 	result = tcp_send_direct(sock, uvreq);
 	if (result != ISC_R_SUCCESS) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		isc__nm_failed_send_cb(sock, uvreq, result);
+		isc__nm_failed_send_cb(sock, uvreq, result, true);
 	}
 
 	return;
@@ -1050,7 +1050,8 @@ tcp_send_cb(uv_write_t *req, int status) {
 
 	if (status < 0) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		isc__nm_failed_send_cb(sock, uvreq, isc_uverr2result(status));
+		isc__nm_failed_send_cb(sock, uvreq, isc_uverr2result(status),
+				       false);
 		return;
 	}
 
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index e1016bea497..e5f3178ace1 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -1147,7 +1147,8 @@ tcpdns_send_cb(uv_write_t *req, int status) {
 
 	if (status < 0) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		isc__nm_failed_send_cb(sock, uvreq, isc_uverr2result(status));
+		isc__nm_failed_send_cb(sock, uvreq, isc_uverr2result(status),
+				       false);
 		return;
 	}
 
@@ -1233,7 +1234,7 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 	return;
 fail:
 	isc__nm_incstats(sock, STATID_SENDFAIL);
-	isc__nm_failed_send_cb(sock, uvreq, result);
+	isc__nm_failed_send_cb(sock, uvreq, result, true);
 }
 
 static void
diff --git a/lib/isc/netmgr/tlsdns.c b/lib/isc/netmgr/tlsdns.c
index 528e6d442bb..536aa2a7f4b 100644
--- a/lib/isc/netmgr/tlsdns.c
+++ b/lib/isc/netmgr/tlsdns.c
@@ -1794,7 +1794,7 @@ isc__nm_async_tlsdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 	result = tlsdns_send_direct(sock, uvreq);
 	if (result != ISC_R_SUCCESS) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		isc__nm_failed_send_cb(sock, uvreq, result);
+		isc__nm_failed_send_cb(sock, uvreq, result, false);
 	}
 }
 
diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
index 0c5d4cf07d4..6b7ae0810ce 100644
--- a/lib/isc/netmgr/udp.c
+++ b/lib/isc/netmgr/udp.c
@@ -663,8 +663,10 @@ udp_send_cb(uv_udp_send_t *req, int status) {
 	REQUIRE(sock->tid == isc_tid());
 
 	if (status < 0) {
-		result = isc_uverr2result(status);
 		isc__nm_incstats(sock, STATID_SENDFAIL);
+		isc__nm_failed_send_cb(sock, uvreq, isc_uverr2result(status),
+				       false);
+		return;
 	}
 
 	isc__nm_sendcb(sock, uvreq, result, false);
@@ -744,7 +746,7 @@ isc__nm_udp_send(isc_nmhandle_t *handle, const isc_region_t *region,
 	}
 	return;
 fail:
-	isc__nm_failed_send_cb(sock, uvreq, result);
+	isc__nm_failed_send_cb(sock, uvreq, result, true);
 }
 
 static isc_result_t