server: pool: remove pool implementation

Quite a lot of code for a tiny improvement. Lease the Pool boolean
option in server so current code does not break. Will be removed
in later versions.

pool.go

@@ -1,61 +0,0 @@
-// Copyright 2011 Miek Gieben. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package dns
-
-// Inspired copied from:
-// http://blog.cloudflare.com/recycling-memory-buffers-in-go
-// ... carries no license ...
-
-import (
-	"container/list"
-	"time"
-)
-
-func mkBuf(size int) []byte { return make([]byte, size) }
-
-type queued struct {
-	when time.Time
-	buf  []byte
-}
-
-func pool(size, bufsize int) (get, give chan []byte) {
-	get = make(chan []byte, bufsize)
-	give = make(chan []byte, bufsize)
-
-	go func() {
-		q := new(list.List)
-		for {
-			e := q.Front()
-			if e == nil {
-				q.PushFront(queued{when: time.Now(), buf: mkBuf(size)})
-				e = q.Front()
-			}
-
-			timeout := time.NewTimer(time.Minute)
-			select {
-			case b := <-give:
-				timeout.Stop()
-				q.PushFront(queued{when: time.Now(), buf: b})
-
-			case get <- e.Value.(queued).buf:
-				timeout.Stop()
-				q.Remove(e)
-
-			case <-timeout.C:
-				e := q.Front()
-				for e != nil {
-					n := e.Next()
-					if time.Since(e.Value.(queued).when) > time.Minute {
-						q.Remove(e)
-						e.Value = nil
-					}
-					e = n
-				}
-			}
-		}
-
-	}()
-	return
-}

server.go

@@ -209,10 +209,8 @@ type Server struct {
 	IdleTimeout func() time.Duration
 	// Secret(s) for Tsig map[<zonename>]<base64 secret>.
 	TsigSecret map[string]string
-	// If true use a pool to recycle buffers for UDP queries.
+	// If true use a pool to recycle buffers for UDP queries, this is now a noop.
 	Pool bool
-	// channels for the pool
-	get, give chan []byte
 }
 
 // ListenAndServe starts a nameserver on the configured address in *Server.
@@ -224,9 +222,6 @@ func (srv *Server) ListenAndServe() error {
 	if srv.UDPSize == 0 {
 		srv.UDPSize = MinMsgSize
 	}
-	if srv.Pool {
-		srv.get, srv.give = pool(srv.UDPSize, 400) // Arbitrary number.
-	}
 	switch srv.Net {
 	case "tcp", "tcp4", "tcp6":
 		a, e := net.ResolveTCPAddr(srv.Net, addr)
@@ -308,9 +303,6 @@ func (srv *Server) serve(a net.Addr, h Handler, m []byte, u *net.UDPConn, t *net
 Redo:
 	req := new(Msg)
 	err := req.Unpack(m)
-	if srv.Pool && u != nil {
-		srv.give <- m[:srv.UDPSize]
-	}
 	if err != nil { // Send a FormatError back
 		x := new(Msg)
 		x.SetRcodeFormatError(req)
@@ -394,12 +386,7 @@ func (srv *Server) readTCP(conn *net.TCPConn, timeout time.Duration) ([]byte, er
 }
 
 func (srv *Server) readUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, net.Addr, error) {
-	var m []byte
-	if srv.Pool {
-		m = <-srv.get
-	} else {
-		m = make([]byte, srv.UDPSize)
-	}
+	m := make([]byte, srv.UDPSize)
 	n, a, e := conn.ReadFromUDP(m)
 	if e != nil || n == 0 {
 		if e != nil {