From: Witold Kręcicki <wpk@isc.org>
Date: Wed, 29 Jan 2020 12:16:04 +0000 (+0100)
Subject: Make nm->recvbuf larger and heap allocated, to allow uv_recvmmsg usage.
X-Git-Tag: v9.17.1~109^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a0d36d760199e71281e17fa8e4bb276a7cabf839;p=thirdparty%2Fbind9.git

Make nm->recvbuf larger and heap allocated, to allow uv_recvmmsg usage.

Upcoming version of libuv will suport uv_recvmmsg and uv_sendmmsg. To
use uv_recvmmsg we need to provide a larger buffer and be able to
properly free it.
---

diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
index 653aa01cb07..2c788004060 100644
--- a/lib/isc/netmgr/netmgr-int.h
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -35,6 +35,19 @@
 
 #define ISC_NETMGR_TID_UNKNOWN -1
 
+#if !defined(WIN32)
+/*
+ * New versions of libuv support recvmmsg on unices.
+ * Since recvbuf is only allocated per worker allocating a bigger one is not
+ * that wasteful.
+ * 20 here is UV__MMSG_MAXWIDTH taken from the current libuv source, nothing
+ * will break if the original value changes.
+ */
+#define ISC_NETMGR_RECVBUF_SIZE (20 * 65536)
+#else
+#define ISC_NETMGR_RECVBUF_SIZE (65536)
+#endif
+
 /*
  * Single network event loop worker.
  */
@@ -56,7 +69,7 @@ typedef struct isc__networker {
 				    * worker is paused */
 	isc_refcount_t references;
 	atomic_int_fast64_t pktcount;
-	char recvbuf[65536];
+	char *recvbuf;
 	bool recvbuf_inuse;
 } isc__networker_t;
 
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index d4a4730eb6a..ca0b1850076 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -196,6 +196,7 @@ isc_nm_start(isc_mem_t *mctx, uint32_t workers) {
 
 		worker->ievents = isc_queue_new(mgr->mctx, 128);
 		worker->ievents_prio = isc_queue_new(mgr->mctx, 128);
+		worker->recvbuf = isc_mem_get(mctx, ISC_NETMGR_RECVBUF_SIZE);
 
 		/*
 		 * We need to do this here and not in nm_thread to avoid a
@@ -268,6 +269,8 @@ nm_destroy(isc_nm_t **mgr0) {
 
 		isc_queue_destroy(worker->ievents);
 		isc_queue_destroy(worker->ievents_prio);
+		isc_mem_put(mgr->mctx, worker->recvbuf,
+			    ISC_NETMGR_RECVBUF_SIZE);
 		isc_thread_join(worker->thread, NULL);
 	}
 
@@ -960,14 +963,14 @@ isc__nm_alloc_cb(uv_handle_t *handle, size_t size, uv_buf_t *buf) {
 
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(isc__nm_in_netthread());
-	REQUIRE(size <= 65536);
+	REQUIRE(size <= ISC_NETMGR_RECVBUF_SIZE);
 
 	worker = &sock->mgr->workers[sock->tid];
 	INSIST(!worker->recvbuf_inuse);
 
 	buf->base = worker->recvbuf;
 	worker->recvbuf_inuse = true;
-	buf->len = size;
+	buf->len = ISC_NETMGR_RECVBUF_SIZE;
 }
 
 void
@@ -982,8 +985,13 @@ isc__nm_free_uvbuf(isc_nmsocket_t *sock, const uv_buf_t *buf) {
 	worker = &sock->mgr->workers[sock->tid];
 
 	REQUIRE(worker->recvbuf_inuse);
+	if (buf->base > worker->recvbuf &&
+	    buf->base <= worker->recvbuf + ISC_NETMGR_RECVBUF_SIZE)
+	{
+		/* Can happen in case of recvmmsg */
+		return;
+	}
 	REQUIRE(buf->base == worker->recvbuf);
-
 	worker->recvbuf_inuse = false;
 }