From: Evan Hunt <each@isc.org>
Date: Wed, 9 Dec 2020 23:45:13 +0000 (-0800)
Subject: Simplify dns_dispatchmgr_create with fixed buffersize
X-Git-Tag: v9.17.19~15^2~25
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ca11f68d61dd2dfc9140ac24d41ba8e48e322f47;p=thirdparty%2Fbind9.git

Simplify dns_dispatchmgr_create with fixed buffersize

- UDP buffersize is now established when creating dispatch manager
  and is always set to 4096.

- Set up the default port range in dispatchmgr before setting the magic
  number.

- Magic is not set until dispatchmgr is fully created.
---

diff --git a/bin/named/server.c b/bin/named/server.c
index e9d3bdc59e7..c7638f8fb18 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -1334,9 +1334,9 @@ get_view_querysource_dispatch(const cfg_obj_t **maps, int af,
 	}
 
 	disp = NULL;
-	result = dns_dispatch_getudp(
-		named_g_dispatchmgr, named_g_socketmgr, named_g_taskmgr, &sa,
-		4096, maxdispatchbuffers, 32768, 16411, 16433, attrs, &disp);
+	result = dns_dispatch_getudp(named_g_dispatchmgr, named_g_socketmgr,
+				     named_g_taskmgr, &sa, maxdispatchbuffers,
+				     32768, 16411, 16433, attrs, &disp);
 	if (result != ISC_R_SUCCESS) {
 		isc_sockaddr_t any;
 		char buf[ISC_SOCKADDR_FORMATSIZE];
@@ -10394,7 +10394,7 @@ named_add_reserved_dispatch(named_server_t *server,
 	}
 
 	result = dns_dispatch_getudp(named_g_dispatchmgr, named_g_socketmgr,
-				     named_g_taskmgr, &dispatch->addr, 4096,
+				     named_g_taskmgr, &dispatch->addr,
 				     UDPBUFFERS, 32768, 16411, 16433, attrs,
 				     &dispatch->dispatch);
 	if (result != ISC_R_SUCCESS) {
diff --git a/bin/nsupdate/nsupdate.c b/bin/nsupdate/nsupdate.c
index fc46a85ce06..bc39de6725d 100644
--- a/bin/nsupdate/nsupdate.c
+++ b/bin/nsupdate/nsupdate.c
@@ -97,7 +97,6 @@
 
 #define MAXCMD	     (128 * 1024)
 #define MAXWIRE	     (64 * 1024)
-#define PACKETSIZE   ((64 * 1024) - 1)
 #define INITTEXT     (2 * 1024)
 #define MAXTEXT	     (128 * 1024)
 #define FIND_TIMEOUT 5
@@ -943,8 +942,8 @@ setup_system(void) {
 		attrs |= DNS_DISPATCHATTR_IPV6;
 		isc_sockaddr_any6(&bind_any6);
 		result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
-					     &bind_any6, PACKETSIZE, 4, 2, 3, 5,
-					     attrs, &dispatchv6);
+					     &bind_any6, 4, 2, 3, 5, attrs,
+					     &dispatchv6);
 		check_result(result, "dns_dispatch_getudp (v6)");
 	}
 
@@ -954,8 +953,8 @@ setup_system(void) {
 		attrs |= DNS_DISPATCHATTR_IPV4;
 		isc_sockaddr_any(&bind_any);
 		result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
-					     &bind_any, PACKETSIZE, 4, 2, 3, 5,
-					     attrs, &dispatchv4);
+					     &bind_any, 4, 2, 3, 5, attrs,
+					     &dispatchv4);
 		check_result(result, "dns_dispatch_getudp (v4)");
 	}
 
diff --git a/bin/tests/system/pipelined/pipequeries.c b/bin/tests/system/pipelined/pipequeries.c
index b4595c7eff8..3fe14e2794e 100644
--- a/bin/tests/system/pipelined/pipequeries.c
+++ b/bin/tests/system/pipelined/pipequeries.c
@@ -286,8 +286,8 @@ main(int argc, char *argv[]) {
 		DNS_DISPATCHATTR_IPV4;
 	dispatchv4 = NULL;
 	RUNCHECK(dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
-				     have_src ? &srcaddr : &bind_any, 4096, 4,
-				     2, 3, 5, attrs, &dispatchv4));
+				     have_src ? &srcaddr : &bind_any, 4, 2, 3,
+				     5, attrs, &dispatchv4));
 	requestmgr = NULL;
 	RUNCHECK(dns_requestmgr_create(mctx, timermgr, socketmgr, taskmgr,
 				       dispatchmgr, dispatchv4, NULL,
diff --git a/bin/tests/system/tkey/keycreate.c b/bin/tests/system/tkey/keycreate.c
index 13da1f6117e..14fb88857bb 100644
--- a/bin/tests/system/tkey/keycreate.c
+++ b/bin/tests/system/tkey/keycreate.c
@@ -245,7 +245,7 @@ main(int argc, char *argv[]) {
 		DNS_DISPATCHATTR_IPV4;
 	dispatchv4 = NULL;
 	RUNCHECK(dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &bind_any,
-				     4096, 4, 2, 3, 5, attrs, &dispatchv4));
+				     4, 2, 3, 5, attrs, &dispatchv4));
 	requestmgr = NULL;
 	RUNCHECK(dns_requestmgr_create(mctx, timermgr, socketmgr, taskmgr,
 				       dispatchmgr, dispatchv4, NULL,
diff --git a/bin/tests/system/tkey/keydelete.c b/bin/tests/system/tkey/keydelete.c
index 92f37fb1c14..605be6ecc06 100644
--- a/bin/tests/system/tkey/keydelete.c
+++ b/bin/tests/system/tkey/keydelete.c
@@ -188,7 +188,7 @@ main(int argc, char **argv) {
 		DNS_DISPATCHATTR_IPV4;
 	dispatchv4 = NULL;
 	RUNCHECK(dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &bind_any,
-				     4096, 4, 2, 3, 5, attrs, &dispatchv4));
+				     4, 2, 3, 5, attrs, &dispatchv4));
 	requestmgr = NULL;
 	RUNCHECK(dns_requestmgr_create(mctx, timermgr, socketmgr, taskmgr,
 				       dispatchmgr, dispatchv4, NULL,
diff --git a/bin/tools/mdig.c b/bin/tools/mdig.c
index e2ca8ca0f0d..df039afe906 100644
--- a/bin/tools/mdig.c
+++ b/bin/tools/mdig.c
@@ -759,7 +759,7 @@ sendquery(struct query *query, isc_task_t *task) {
 		requestmgr, message, have_src ? &srcaddr : NULL, &dstaddr, dscp,
 		options, NULL, query->timeout, query->udptimeout,
 		query->udpretries, task, recvresponse, message, &request);
-	CHECK("dns_request_createvia4", result);
+	CHECK("dns_request_createvia", result);
 
 	return (ISC_R_SUCCESS);
 }
@@ -2141,8 +2141,8 @@ main(int argc, char *argv[]) {
 	}
 	dispatchvx = NULL;
 	RUNCHECK(dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr,
-				     have_src ? &srcaddr : &bind_any, 4096, 100,
-				     100, 17, 19, attrs, &dispatchvx));
+				     have_src ? &srcaddr : &bind_any, 100, 100,
+				     17, 19, attrs, &dispatchvx));
 	RUNCHECK(dns_requestmgr_create(
 		mctx, timermgr, socketmgr, taskmgr, dispatchmgr,
 		have_ipv4 ? dispatchvx : NULL, have_ipv6 ? dispatchvx : NULL,
diff --git a/lib/dns/client.c b/lib/dns/client.c
index 78b1efcf4eb..ce2c7e325c5 100644
--- a/lib/dns/client.c
+++ b/lib/dns/client.c
@@ -207,7 +207,7 @@ getudpdispatch(int family, dns_dispatchmgr_t *dispatchmgr,
 	       const isc_sockaddr_t *localaddr) {
 	unsigned int attrs;
 	dns_dispatch_t *disp;
-	unsigned buffersize, maxbuffers, maxrequests, buckets, increment;
+	unsigned maxbuffers, maxrequests, buckets, increment;
 	isc_result_t result;
 	isc_sockaddr_t anyaddr;
 
@@ -230,7 +230,6 @@ getudpdispatch(int family, dns_dispatchmgr_t *dispatchmgr,
 		localaddr = &anyaddr;
 	}
 
-	buffersize = 4096;
 	maxbuffers = is_shared ? 1000 : 8;
 	maxrequests = 32768;
 	buckets = is_shared ? 16411 : 3;
@@ -238,8 +237,8 @@ getudpdispatch(int family, dns_dispatchmgr_t *dispatchmgr,
 
 	disp = NULL;
 	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, localaddr,
-				     buffersize, maxbuffers, maxrequests,
-				     buckets, increment, attrs, &disp);
+				     maxbuffers, maxrequests, buckets,
+				     increment, attrs, &disp);
 	if (result == ISC_R_SUCCESS) {
 		*dispp = disp;
 	}
diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c
index 080407e0bab..e8de005bc5e 100644
--- a/lib/dns/dispatch.c
+++ b/lib/dns/dispatch.c
@@ -139,6 +139,13 @@ struct dns_dispentry {
 #define DNS_DISPATCH_SOCKSQUOTA 3072
 #endif /* ifndef DNS_DISPATCH_SOCKSQUOTA */
 
+/*%
+ * Fixed UDP buffer size.
+ */
+#ifndef DNS_DISPATCH_UDPBUFSIZE
+#define DNS_DISPATCH_UDPBUFSIZE 4096
+#endif /* ifndef DNS_DISPATCH_UDPBUFSIZE */
+
 struct dispsocket {
 	unsigned int magic;
 	isc_socket_t *socket;
@@ -587,7 +594,6 @@ new_portentry(dns_dispatch_t *disp, in_port_t port) {
 	REQUIRE(disp->port_table != NULL);
 
 	portentry = isc_mem_get(disp->mgr->mctx, sizeof(*portentry));
-
 	portentry->port = port;
 	isc_refcount_init(&portentry->refs, 1);
 	ISC_LINK_INIT(portentry, link);
@@ -730,10 +736,6 @@ get_dispsocket(dns_dispatch_t *disp, const isc_sockaddr_t *dest,
 		if (result == ISC_R_SUCCESS) {
 			if (portentry == NULL) {
 				portentry = new_portentry(disp, port);
-				if (portentry == NULL) {
-					result = ISC_R_NOMEMORY;
-					break;
-				}
 			} else {
 				isc_refcount_increment(&portentry->refs);
 			}
@@ -794,7 +796,6 @@ destroy_dispsocket(dns_dispatch_t *disp, dispsocket_t **dispsockp) {
 	disp->nsockets--;
 	dispsock->magic = 0;
 	if (dispsock->portentry != NULL) {
-		/* socket_search() tests and dereferences portentry. */
 		LOCK(&qid->lock);
 		deref_portentry(disp, &dispsock->portentry);
 		UNLOCK(&qid->lock);
@@ -833,7 +834,7 @@ deactivate_dispsocket(dns_dispatch_t *disp, dispsocket_t *dispsock) {
 	}
 
 	INSIST(dispsock->portentry != NULL);
-	/* socket_search() tests and dereferences portentry. */
+
 	LOCK(&qid->lock);
 	deref_portentry(disp, &dispsock->portentry);
 	UNLOCK(&qid->lock);
@@ -890,8 +891,7 @@ entry_search(dns_qid_t *qid, const isc_sockaddr_t *dest, dns_messageid_t id,
 
 static void
 free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len) {
-	unsigned int buffersize;
-	INSIST(buf != NULL && len != 0);
+	REQUIRE(buf != NULL && len != 0);
 
 	switch (disp->socktype) {
 	case isc_sockettype_tcp:
@@ -902,11 +902,10 @@ free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len) {
 	case isc_sockettype_udp:
 		LOCK(&disp->mgr->buffer_lock);
 		INSIST(disp->mgr->buffers > 0);
-		INSIST(len == disp->mgr->buffersize);
+		INSIST(len == DNS_DISPATCH_UDPBUFSIZE);
 		disp->mgr->buffers--;
-		buffersize = disp->mgr->buffersize;
 		UNLOCK(&disp->mgr->buffer_lock);
-		isc_mem_put(disp->mgr->mctx, buf, buffersize);
+		isc_mem_put(disp->mgr->mctx, buf, len);
 		break;
 	default:
 		INSIST(0);
@@ -916,18 +915,15 @@ free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len) {
 
 static void *
 allocate_udp_buffer(dns_dispatch_t *disp) {
-	unsigned int buffersize;
-
 	LOCK(&disp->mgr->buffer_lock);
 	if (disp->mgr->buffers >= disp->mgr->maxbuffers) {
 		UNLOCK(&disp->mgr->buffer_lock);
 		return (NULL);
 	}
-	buffersize = disp->mgr->buffersize;
 	disp->mgr->buffers++;
 	UNLOCK(&disp->mgr->buffer_lock);
 
-	return (isc_mem_get(disp->mgr->mctx, buffersize));
+	return (isc_mem_get(disp->mgr->mctx, DNS_DISPATCH_UDPBUFSIZE));
 }
 
 static inline void
@@ -1520,7 +1516,7 @@ startrecv(dns_dispatch_t *disp, dispsocket_t *dispsock) {
 	 * UDP reads are always maximal.
 	 */
 	case isc_sockettype_udp:
-		region.length = disp->mgr->buffersize;
+		region.length = DNS_DISPATCH_UDPBUFSIZE;
 		region.base = allocate_udp_buffer(disp);
 		if (region.base == NULL) {
 			return (ISC_R_NOMEMORY);
@@ -1699,15 +1695,57 @@ open_socket(isc_socketmgr_t *mgr, const isc_sockaddr_t *local,
  * normally set the ports explicitly, but is provided to fill some minor corner
  * cases.
  */
-static isc_result_t
+static void
 create_default_portset(isc_mem_t *mctx, isc_portset_t **portsetp) {
-	isc_result_t result;
+	isc_portset_create(mctx, portsetp);
+	isc_portset_addrange(*portsetp, 1024, 65535);
+}
 
-	result = isc_portset_create(mctx, portsetp);
-	if (result != ISC_R_SUCCESS) {
-		return (result);
+static isc_result_t
+setavailports(dns_dispatchmgr_t *mgr, isc_portset_t *v4portset,
+	      isc_portset_t *v6portset) {
+	in_port_t *v4ports, *v6ports, p = 0;
+	unsigned int nv4ports, nv6ports, i4 = 0, i6 = 0;
+
+	nv4ports = isc_portset_nports(v4portset);
+	nv6ports = isc_portset_nports(v6portset);
+
+	v4ports = NULL;
+	if (nv4ports != 0) {
+		v4ports = isc_mem_get(mgr->mctx, sizeof(in_port_t) * nv4ports);
 	}
-	isc_portset_addrange(*portsetp, 1024, 65535);
+	v6ports = NULL;
+	if (nv6ports != 0) {
+		v6ports = isc_mem_get(mgr->mctx, sizeof(in_port_t) * nv6ports);
+	}
+
+	do {
+		if (isc_portset_isset(v4portset, p)) {
+			INSIST(i4 < nv4ports);
+			v4ports[i4++] = p;
+		}
+		if (isc_portset_isset(v6portset, p)) {
+			INSIST(i6 < nv6ports);
+			v6ports[i6++] = p;
+		}
+	} while (p++ < 65535);
+	INSIST(i4 == nv4ports && i6 == nv6ports);
+
+	PORTBUFLOCK(mgr);
+	if (mgr->v4ports != NULL) {
+		isc_mem_put(mgr->mctx, mgr->v4ports,
+			    mgr->nv4ports * sizeof(in_port_t));
+	}
+	mgr->v4ports = v4ports;
+	mgr->nv4ports = nv4ports;
+
+	if (mgr->v6ports != NULL) {
+		isc_mem_put(mgr->mctx, mgr->v6ports,
+			    mgr->nv6ports * sizeof(in_port_t));
+	}
+	mgr->v6ports = v6ports;
+	mgr->nv6ports = nv6ports;
+	PORTBUFUNLOCK(mgr);
 
 	return (ISC_R_SUCCESS);
 }
@@ -1718,8 +1756,7 @@ create_default_portset(isc_mem_t *mctx, isc_portset_t **portsetp) {
 
 isc_result_t
 dns_dispatchmgr_create(isc_mem_t *mctx, dns_dispatchmgr_t **mgrp) {
-	dns_dispatchmgr_t *mgr;
-	isc_result_t result;
+	dns_dispatchmgr_t *mgr = NULL;
 	isc_portset_t *v4portset = NULL;
 	isc_portset_t *v6portset = NULL;
 
@@ -1727,7 +1764,7 @@ dns_dispatchmgr_create(isc_mem_t *mctx, dns_dispatchmgr_t **mgrp) {
 	REQUIRE(mgrp != NULL && *mgrp == NULL);
 
 	mgr = isc_mem_get(mctx, sizeof(dns_dispatchmgr_t));
-	*mgr = (dns_dispatchmgr_t){ 0 };
+	*mgr = (dns_dispatchmgr_t){ .maxbuffers = 20000 };
 
 	isc_mem_attach(mctx, &mgr->mctx);
 
@@ -1738,35 +1775,18 @@ dns_dispatchmgr_create(isc_mem_t *mctx, dns_dispatchmgr_t **mgrp) {
 
 	ISC_LIST_INIT(mgr->list);
 
-	mgr->magic = DNS_DISPATCHMGR_MAGIC;
+	create_default_portset(mctx, &v4portset);
+	create_default_portset(mctx, &v6portset);
 
-	result = create_default_portset(mctx, &v4portset);
-	if (result == ISC_R_SUCCESS) {
-		result = create_default_portset(mctx, &v6portset);
-		if (result == ISC_R_SUCCESS) {
-			result = dns_dispatchmgr_setavailports(mgr, v4portset,
-							       v6portset);
-		}
-	}
-	if (v4portset != NULL) {
-		isc_portset_destroy(mctx, &v4portset);
-	}
-	if (v6portset != NULL) {
-		isc_portset_destroy(mctx, &v6portset);
-	}
-	if (result != ISC_R_SUCCESS) {
-		goto kill_dpool;
-	}
+	setavailports(mgr, v4portset, v6portset);
 
-	*mgrp = mgr;
-	return (ISC_R_SUCCESS);
+	isc_portset_destroy(mctx, &v4portset);
+	isc_portset_destroy(mctx, &v6portset);
 
-kill_dpool:
-	isc_mutex_destroy(&mgr->buffer_lock);
-	isc_mutex_destroy(&mgr->lock);
-	isc_mem_putanddetach(&mctx, mgr, sizeof(dns_dispatchmgr_t));
+	mgr->magic = DNS_DISPATCHMGR_MAGIC;
 
-	return (result);
+	*mgrp = mgr;
+	return (ISC_R_SUCCESS);
 }
 
 void
@@ -1787,65 +1807,17 @@ dns_dispatchmgr_getblackhole(dns_dispatchmgr_t *mgr) {
 isc_result_t
 dns_dispatchmgr_setavailports(dns_dispatchmgr_t *mgr, isc_portset_t *v4portset,
 			      isc_portset_t *v6portset) {
-	in_port_t *v4ports, *v6ports, p;
-	unsigned int nv4ports, nv6ports, i4, i6;
-
 	REQUIRE(VALID_DISPATCHMGR(mgr));
-
-	nv4ports = isc_portset_nports(v4portset);
-	nv6ports = isc_portset_nports(v6portset);
-
-	v4ports = NULL;
-	if (nv4ports != 0) {
-		v4ports = isc_mem_get(mgr->mctx, sizeof(in_port_t) * nv4ports);
-	}
-	v6ports = NULL;
-	if (nv6ports != 0) {
-		v6ports = isc_mem_get(mgr->mctx, sizeof(in_port_t) * nv6ports);
-	}
-
-	p = 0;
-	i4 = 0;
-	i6 = 0;
-	do {
-		if (isc_portset_isset(v4portset, p)) {
-			INSIST(i4 < nv4ports);
-			v4ports[i4++] = p;
-		}
-		if (isc_portset_isset(v6portset, p)) {
-			INSIST(i6 < nv6ports);
-			v6ports[i6++] = p;
-		}
-	} while (p++ < 65535);
-	INSIST(i4 == nv4ports && i6 == nv6ports);
-
-	PORTBUFLOCK(mgr);
-	if (mgr->v4ports != NULL) {
-		isc_mem_put(mgr->mctx, mgr->v4ports,
-			    mgr->nv4ports * sizeof(in_port_t));
-	}
-	mgr->v4ports = v4ports;
-	mgr->nv4ports = nv4ports;
-
-	if (mgr->v6ports != NULL) {
-		isc_mem_put(mgr->mctx, mgr->v6ports,
-			    mgr->nv6ports * sizeof(in_port_t));
-	}
-	mgr->v6ports = v6ports;
-	mgr->nv6ports = nv6ports;
-	PORTBUFUNLOCK(mgr);
-
-	return (ISC_R_SUCCESS);
+	return (setavailports(mgr, v4portset, v6portset));
 }
 
 static isc_result_t
-dns_dispatchmgr_setudp(dns_dispatchmgr_t *mgr, unsigned int buffersize,
-		       unsigned int maxbuffers, unsigned int maxrequests,
-		       unsigned int buckets, unsigned int increment) {
+dispatchmgr_setudp(dns_dispatchmgr_t *mgr, unsigned int maxbuffers,
+		   unsigned int maxrequests, unsigned int buckets,
+		   unsigned int increment) {
 	isc_result_t result;
 
 	REQUIRE(VALID_DISPATCHMGR(mgr));
-	REQUIRE(buffersize >= 512 && buffersize < (64 * 1024));
 	REQUIRE(maxbuffers > 0);
 	REQUIRE(buckets < 2097169); /* next prime > 65536 * 32 */
 	REQUIRE(increment > buckets);
@@ -1868,31 +1840,29 @@ dns_dispatchmgr_setudp(dns_dispatchmgr_t *mgr, unsigned int buffersize,
 		maxbuffers = 8;
 	}
 
+	/* Adjust buffer pool if needed
+	 *
+	 * We only increase maxbuffers to avoid accidental buffer
+	 * shortage.  Ideally we'd separate the manager-wide maximum
+	 * from per-dispatch limits and respect the latter within the
+	 * global limit.  But at this moment that's deemed to be
+	 * overkilling and isn't worth additional implementation
+	 * complexity.
+	 */
 	LOCK(&mgr->buffer_lock);
-
 	if (maxbuffers > mgr->maxbuffers) {
 		mgr->maxbuffers = maxbuffers;
 	}
+	UNLOCK(&mgr->buffer_lock);
 
-	/* Create or adjust socket pool */
-	if (mgr->qid != NULL) {
-		UNLOCK(&mgr->buffer_lock);
-		return (ISC_R_SUCCESS);
-	}
-
-	result = qid_allocate(mgr, buckets, increment, &mgr->qid, true);
-	if (result != ISC_R_SUCCESS) {
-		goto cleanup;
+	if (mgr->qid == NULL) {
+		result = qid_allocate(mgr, buckets, increment, &mgr->qid, true);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
 	}
 
-	mgr->buffersize = buffersize;
-	mgr->maxbuffers = maxbuffers;
-	UNLOCK(&mgr->buffer_lock);
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	UNLOCK(&mgr->buffer_lock);
-	return (result);
 }
 
 void
@@ -2351,10 +2321,9 @@ dns_dispatch_gettcp(dns_dispatchmgr_t *mgr, const isc_sockaddr_t *destaddr,
 isc_result_t
 dns_dispatch_getudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
 		    isc_taskmgr_t *taskmgr, const isc_sockaddr_t *localaddr,
-		    unsigned int buffersize, unsigned int maxbuffers,
-		    unsigned int maxrequests, unsigned int buckets,
-		    unsigned int increment, unsigned int attributes,
-		    dns_dispatch_t **dispp) {
+		    unsigned int maxbuffers, unsigned int maxrequests,
+		    unsigned int buckets, unsigned int increment,
+		    unsigned int attributes, dns_dispatch_t **dispp) {
 	isc_result_t result;
 	dns_dispatch_t *disp = NULL;
 
@@ -2362,15 +2331,14 @@ dns_dispatch_getudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
 	REQUIRE(sockmgr != NULL);
 	REQUIRE(localaddr != NULL);
 	REQUIRE(taskmgr != NULL);
-	REQUIRE(buffersize >= 512 && buffersize < (64 * 1024));
 	REQUIRE(maxbuffers > 0);
 	REQUIRE(buckets < 2097169); /* next prime > 65536 * 32 */
 	REQUIRE(increment > buckets);
 	REQUIRE(dispp != NULL && *dispp == NULL);
 	REQUIRE((attributes & DNS_DISPATCHATTR_TCP) == 0);
 
-	result = dns_dispatchmgr_setudp(mgr, buffersize, maxbuffers,
-					maxrequests, buckets, increment);
+	result = dispatchmgr_setudp(mgr, maxbuffers, maxrequests, buckets,
+				    increment);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
diff --git a/lib/dns/include/dns/dispatch.h b/lib/dns/include/dns/dispatch.h
index e2d910e28f0..ddedac07b54 100644
--- a/lib/dns/include/dns/dispatch.h
+++ b/lib/dns/include/dns/dispatch.h
@@ -139,7 +139,8 @@ struct dns_dispatchset {
 isc_result_t
 dns_dispatchmgr_create(isc_mem_t *mctx, dns_dispatchmgr_t **mgrp);
 /*%<
- * Creates a new dispatchmgr object.
+ * Creates a new dispatchmgr object, and sets the available ports
+ * to the default range (1024-65535).
  *
  * Requires:
  *\li	"mctx" be a valid memory context.
@@ -215,10 +216,9 @@ dns_dispatchmgr_setstats(dns_dispatchmgr_t *mgr, isc_stats_t *stats);
 isc_result_t
 dns_dispatch_getudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
 		    isc_taskmgr_t *taskmgr, const isc_sockaddr_t *localaddr,
-		    unsigned int buffersize, unsigned int maxbuffers,
-		    unsigned int maxrequests, unsigned int buckets,
-		    unsigned int increment, unsigned int attributes,
-		    dns_dispatch_t **dispp);
+		    unsigned int maxbuffers, unsigned int maxrequests,
+		    unsigned int buckets, unsigned int increment,
+		    unsigned int attributes, dns_dispatch_t **dispp);
 /*%<
  * Attach to existing dns_dispatch_t if one is found with dns_dispatchmgr_find,
  * otherwise create a new UDP dispatch.
diff --git a/lib/dns/request.c b/lib/dns/request.c
index 1311de4027e..fc6a1c89650 100644
--- a/lib/dns/request.c
+++ b/lib/dns/request.c
@@ -630,8 +630,8 @@ find_udp_dispatch(dns_requestmgr_t *requestmgr, const isc_sockaddr_t *srcaddr,
 	}
 	return (dns_dispatch_getudp(requestmgr->dispatchmgr,
 				    requestmgr->socketmgr, requestmgr->taskmgr,
-				    srcaddr, 4096, 32768, 32768, 16411, 16433,
-				    attrs, dispatchp));
+				    srcaddr, 32768, 32768, 16411, 16433, attrs,
+				    dispatchp));
 }
 
 static isc_result_t
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 0358241d954..4652f043708 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -2175,7 +2175,7 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
 			}
 			result = dns_dispatch_getudp(
 				res->dispatchmgr, res->socketmgr, res->taskmgr,
-				&addr, 4096, 20000, 32768, 16411, 16433, attrs,
+				&addr, 20000, 32768, 16411, 16433, attrs,
 				&query->dispatch);
 			if (result != ISC_R_SUCCESS) {
 				goto cleanup_query;
diff --git a/lib/dns/tests/dispatch_test.c b/lib/dns/tests/dispatch_test.c
index a425091bf68..5bc81a2cd56 100644
--- a/lib/dns/tests/dispatch_test.c
+++ b/lib/dns/tests/dispatch_test.c
@@ -76,8 +76,8 @@ make_dispatchset(unsigned int ndisps) {
 
 	isc_sockaddr_any(&any);
 	attrs = DNS_DISPATCHATTR_IPV4 | DNS_DISPATCHATTR_UDP;
-	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &any, 512,
-				     6, 1024, 17, 19, attrs, &disp);
+	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &any, 6,
+				     1024, 17, 19, attrs, &disp);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -274,8 +274,8 @@ dispatch_getnext(void **state) {
 	ina.s_addr = htonl(INADDR_LOOPBACK);
 	isc_sockaddr_fromin(&local, &ina, 0);
 	attrs = DNS_DISPATCHATTR_IPV4 | DNS_DISPATCHATTR_UDP;
-	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &local,
-				     512, 6, 1024, 17, 19, attrs, &dispatch);
+	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &local, 6,
+				     1024, 17, 19, attrs, &dispatch);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	/*
diff --git a/lib/dns/tests/resolver_test.c b/lib/dns/tests/resolver_test.c
index c115c34d8ce..b144e09f846 100644
--- a/lib/dns/tests/resolver_test.c
+++ b/lib/dns/tests/resolver_test.c
@@ -58,7 +58,7 @@ _setup(void **state) {
 
 	isc_sockaddr_any(&local);
 	result = dns_dispatch_getudp(dispatchmgr, socketmgr, taskmgr, &local,
-				     4096, 100, 100, 100, 500, 0, &dispatch);
+				     100, 100, 100, 500, 0, &dispatch);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	return (0);
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 7bd8c05c9b6..9b26c61ffe9 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -14603,8 +14603,7 @@ again:
 		zone->task, refresh_callback, zone, &zone->request);
 	if (result != ISC_R_SUCCESS) {
 		zone_idetach(&dummy);
-		zone_debuglog(zone, me, 1,
-			      "dns_request_createvia4() failed: %s",
+		zone_debuglog(zone, me, 1, "dns_request_createvia() failed: %s",
 			      dns_result_totext(result));
 		goto skip_master;
 	} else {