Add a timeout to RemoteAddr() to allow http.Serve in go < 1.6 work

README.md

@@ -28,7 +28,7 @@ Using the library is very simple:
 list, err := net.Listen("tcp", "...")
 
 // Wrap listener in a proxyproto listener
-proxyList := &proxyproto.Listener{list}
+proxyList := &proxyproto.Listener{Listener: list}
 conn, err :=proxyList.Accept()
 
 ...

protocol.go

@@ -24,19 +24,24 @@ var (
 // whose connections may be using the HAProxy Proxy Protocol (version 1).
 // If the connection is using the protocol, the RemoteAddr() will return
 // the correct client address.
+//
+// Optionally define ProxyHeaderTimeout to set a maximum time to
+// receive the Proxy Protocol Header. Zero means no timeout.
 type Listener struct {
-	Listener net.Listener
+	Listener           net.Listener
+	ProxyHeaderTimeout time.Duration
 }
 
 // Conn is used to wrap and underlying connection which
 // may be speaking the Proxy Protocol. If it is, the RemoteAddr() will
 // return the address of the client instead of the proxy address.
 type Conn struct {
-	bufReader *bufio.Reader
-	conn      net.Conn
-	dstAddr   *net.TCPAddr
-	srcAddr   *net.TCPAddr
-	once      sync.Once
+	bufReader          *bufio.Reader
+	conn               net.Conn
+	dstAddr            *net.TCPAddr
+	srcAddr            *net.TCPAddr
+	once               sync.Once
+	proxyHeaderTimeout time.Duration
 }
 
 // Accept waits for and returns the next connection to the listener.
@@ -46,7 +51,7 @@ func (p *Listener) Accept() (net.Conn, error) {
 	if err != nil {
 		return nil, err
 	}
-	return NewConn(conn), nil
+	return NewConn(conn, p.ProxyHeaderTimeout), nil
 }
 
 // Close closes the underlying listener.
@@ -61,10 +66,11 @@ func (p *Listener) Addr() net.Addr {
 
 // NewConn is used to wrap a net.Conn that may be speaking
 // the proxy protocol into a proxyproto.Conn
-func NewConn(conn net.Conn) *Conn {
+func NewConn(conn net.Conn, timeout time.Duration) *Conn {
 	pConn := &Conn{
-		bufReader: bufio.NewReader(conn),
-		conn:      conn,
+		bufReader:          bufio.NewReader(conn),
+		conn:               conn,
+		proxyHeaderTimeout: timeout,
 	}
 	return pConn
 }
@@ -104,6 +110,8 @@ func (p *Conn) RemoteAddr() net.Addr {
 	p.once.Do(func() {
 		if err := p.checkPrefix(); err != nil && err != io.EOF {
 			log.Printf("[ERR] Failed to read proxy prefix: %v", err)
+			p.Close()
+			p.bufReader = bufio.NewReader(p.conn)
 		}
 	})
 	if p.srcAddr != nil {
@@ -125,11 +133,22 @@ func (p *Conn) SetWriteDeadline(t time.Time) error {
 }
 
 func (p *Conn) checkPrefix() error {
+	if p.proxyHeaderTimeout != 0 {
+		readDeadLine := time.Now().Add(p.proxyHeaderTimeout)
+		p.conn.SetReadDeadline(readDeadLine)
+		defer p.conn.SetReadDeadline(time.Time{})
+	}
+
 	// Incrementally check each byte of the prefix
 	for i := 1; i <= prefixLen; i++ {
 		inp, err := p.bufReader.Peek(i)
+
 		if err != nil {
-			return err
+			if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
+				return nil
+			} else {
+				return err
+			}
 		}
 
 		// Check for a prefix mis-match, quit early

protocol_test.go

@@ -2,9 +2,9 @@ package proxyproto
 
 import (
 	"bytes"
-	"io"
 	"net"
 	"testing"
+	"time"
 )
 
 func TestPassthrough(t *testing.T) {
@@ -13,7 +13,7 @@ func TestPassthrough(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
-	pl := &Listener{l}
+	pl := &Listener{Listener: l}
 
 	go func() {
 		conn, err := net.Dial("tcp", pl.Addr().String())
@@ -53,13 +53,77 @@ func TestPassthrough(t *testing.T) {
 	}
 }
 
+func TestTimeout(t *testing.T) {
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	clientWriteDelay := 200 * time.Millisecond
+	proxyHeaderTimeout := 50 * time.Millisecond
+	pl := &Listener{Listener: l, ProxyHeaderTimeout: proxyHeaderTimeout}
+
+	go func() {
+		conn, err := net.Dial("tcp", pl.Addr().String())
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		defer conn.Close()
+
+		// Do not send data for a while
+		time.Sleep(clientWriteDelay)
+
+		conn.Write([]byte("ping"))
+		recv := make([]byte, 4)
+		_, err = conn.Read(recv)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		if !bytes.Equal(recv, []byte("pong")) {
+			t.Fatalf("bad: %v", recv)
+		}
+	}()
+
+	conn, err := pl.Accept()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	defer conn.Close()
+
+	// Check the remote addr is the original 127.0.0.1
+	remoteAddrStartTime := time.Now()
+	addr := conn.RemoteAddr().(*net.TCPAddr)
+	if addr.IP.String() != "127.0.0.1" {
+		t.Fatalf("bad: %v", addr)
+	}
+	remoteAddrDuration := time.Since(remoteAddrStartTime)
+
+	// Check RemoteAddr() call did timeout
+	if remoteAddrDuration >= clientWriteDelay {
+		t.Fatalf("RemoteAddr() took longer than the specified timeout: %v < %v", proxyHeaderTimeout, remoteAddrDuration)
+	}
+
+	recv := make([]byte, 4)
+	_, err = conn.Read(recv)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !bytes.Equal(recv, []byte("ping")) {
+		t.Fatalf("bad: %v", recv)
+	}
+
+	if _, err := conn.Write([]byte("pong")); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+}
+
 func TestParse_ipv4(t *testing.T) {
 	l, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
 
-	pl := &Listener{l}
+	pl := &Listener{Listener: l}
 
 	go func() {
 		conn, err := net.Dial("tcp", pl.Addr().String())
@@ -118,7 +182,7 @@ func TestParse_ipv6(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
-	pl := &Listener{l}
+	pl := &Listener{Listener: l}
 
 	go func() {
 		conn, err := net.Dial("tcp", pl.Addr().String())
@@ -177,7 +241,7 @@ func TestParse_BadHeader(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	}
 
-	pl := &Listener{l}
+	pl := &Listener{Listener: l}
 
 	go func() {
 		conn, err := net.Dial("tcp", pl.Addr().String())
@@ -194,7 +258,7 @@ func TestParse_BadHeader(t *testing.T) {
 
 		recv := make([]byte, 4)
 		_, err = conn.Read(recv)
-		if err != io.EOF {
+		if err == nil {
 			t.Fatalf("err: %v", err)
 		}
 	}()