net/http: add Next Protocol Negotation upgrade support to the Server

This provides the mechanism to connect SPDY support to the http
package, without pulling SPDY into the standard library.

R=rsc, agl, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/7287045

src/pkg/net/http/httptest/server.go

@@ -21,7 +21,11 @@ import (
 type Server struct {
 	URL      string // base URL of form http://ipaddr:port with no trailing slash
 	Listener net.Listener
-	TLS      *tls.Config // nil if not using TLS
+
+	// TLS is the optional TLS configuration, populated with a new config
+	// after TLS is started. If set on an unstarted server before StartTLS
+	// is called, existing fields are copied into the new config.
+	TLS *tls.Config
 
 	// Config may be changed after calling NewUnstartedServer and
 	// before Start or StartTLS.
@@ -119,9 +123,16 @@ func (s *Server) StartTLS() {
 		panic(fmt.Sprintf("httptest: NewTLSServer: %v", err))
 	}
 
-	s.TLS = &tls.Config{
-		NextProtos:   []string{"http/1.1"},
-		Certificates: []tls.Certificate{cert},
+	existingConfig := s.TLS
+	s.TLS = new(tls.Config)
+	if existingConfig != nil {
+		*s.TLS = *existingConfig
+	}
+	if s.TLS.NextProtos == nil {
+		s.TLS.NextProtos = []string{"http/1.1"}
+	}
+	if len(s.TLS.Certificates) == 0 {
+		s.TLS.Certificates = []tls.Certificate{cert}
 	}
 	tlsListener := tls.NewListener(s.Listener, s.TLS)
 

src/pkg/net/http/npn_test.go

@@ -0,0 +1,118 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http_test
+
+import (
+	"bufio"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"io/ioutil"
+	. "net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestNextProtoUpgrade(t *testing.T) {
+	ts := httptest.NewUnstartedServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		fmt.Fprintf(w, "path=%s,proto=", r.URL.Path)
+		if r.TLS != nil {
+			w.Write([]byte(r.TLS.NegotiatedProtocol))
+		}
+		if r.RemoteAddr == "" {
+			t.Error("request with no RemoteAddr")
+		}
+		if r.Body == nil {
+			t.Errorf("request with nil Body")
+		}
+	}))
+	ts.TLS = &tls.Config{
+		NextProtos: []string{"unhandled-proto", "tls-0.9"},
+	}
+	ts.Config.TLSNextProto = map[string]func(*Server, *tls.Conn, Handler){
+		"tls-0.9": handleTLSProtocol09,
+	}
+	ts.StartTLS()
+	defer ts.Close()
+
+	tr := newTLSTransport(t, ts)
+	defer tr.CloseIdleConnections()
+	c := &Client{Transport: tr}
+
+	// Normal request, without NPN.
+	{
+		res, err := c.Get(ts.URL)
+		if err != nil {
+			t.Fatal(err)
+		}
+		body, err := ioutil.ReadAll(res.Body)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if want := "path=/,proto="; string(body) != want {
+			t.Errorf("plain request = %q; want %q", body, want)
+		}
+	}
+
+	// Request to an advertised but unhandled NPN protocol.
+	// Server will hang up.
+	{
+		tr.CloseIdleConnections()
+		tr.TLSClientConfig.NextProtos = []string{"unhandled-proto"}
+		_, err := c.Get(ts.URL)
+		if err == nil {
+			t.Errorf("expected error on unhandled-proto request")
+		}
+	}
+
+	// Request using the "tls-0.9" protocol, which we register here.
+	// It is HTTP/0.9 over TLS.
+	{
+		tlsConfig := newTLSTransport(t, ts).TLSClientConfig
+		tlsConfig.NextProtos = []string{"tls-0.9"}
+		conn, err := tls.Dial("tcp", ts.Listener.Addr().String(), tlsConfig)
+		if err != nil {
+			t.Fatal(err)
+		}
+		conn.Write([]byte("GET /foo\n"))
+		body, err := ioutil.ReadAll(conn)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if want := "path=/foo,proto=tls-0.9"; string(body) != want {
+			t.Errorf("plain request = %q; want %q", body, want)
+		}
+	}
+}
+
+// handleTLSProtocol09 implements the HTTP/0.9 protocol over TLS, for the
+// TestNextProtoUpgrade test.
+func handleTLSProtocol09(srv *Server, conn *tls.Conn, h Handler) {
+	br := bufio.NewReader(conn)
+	line, err := br.ReadString('\n')
+	if err != nil {
+		return
+	}
+	line = strings.TrimSpace(line)
+	path := strings.TrimPrefix(line, "GET ")
+	if path == line {
+		return
+	}
+	req, _ := NewRequest("GET", path, nil)
+	req.Proto = "HTTP/0.9"
+	req.ProtoMajor = 0
+	req.ProtoMinor = 9
+	rw := &http09Writer{conn, make(Header)}
+	h.ServeHTTP(rw, req)
+}
+
+type http09Writer struct {
+	io.Writer
+	h Header
+}
+
+func (w http09Writer) Header() Header  { return w.h }
+func (w http09Writer) WriteHeader(int) {} // no headers

src/pkg/net/http/server.go

@@ -774,6 +774,18 @@ func (c *conn) closeWriteAndWait() {
 	time.Sleep(rstAvoidanceDelay)
 }
 
+// validNPN returns whether the proto is not a blacklisted Next
+// Protocol Negotiation protocol.  Empty and built-in protocol types
+// are blacklisted and can't be overridden with alternate
+// implementations.
+func validNPN(proto string) bool {
+	switch proto {
+	case "", "http/1.1", "http/1.0":
+		return false
+	}
+	return true
+}
+
 // Serve a new connection.
 func (c *conn) serve() {
 	defer func() {
@@ -800,6 +812,13 @@ func (c *conn) serve() {
 		}
 		c.tlsState = new(tls.ConnectionState)
 		*c.tlsState = tlsConn.ConnectionState()
+		if proto := c.tlsState.NegotiatedProtocol; validNPN(proto) {
+			if fn := c.server.TLSNextProto[proto]; fn != nil {
+				h := initNPNRequest{tlsConn, serverHandler{c.server}}
+				fn(c.server, tlsConn, h)
+			}
+			return
+		}
 	}
 
 	for {
@@ -842,20 +861,12 @@ func (c *conn) serve() {
 			break
 		}
 
-		handler := c.server.Handler
-		if handler == nil {
-			handler = DefaultServeMux
-		}
-		if req.RequestURI == "*" && req.Method == "OPTIONS" {
-			handler = globalOptionsHandler{}
-		}
-
 		// HTTP cannot have multiple simultaneous active requests.[*]
 		// Until the server replies to this request, it can't read another,
 		// so we might as well run the handler in this goroutine.
 		// [*] Not strictly true: HTTP pipelining.  We could let them all process
 		// in parallel even if their responses need to be serialized.
-		handler.ServeHTTP(w, w.req)
+		serverHandler{c.server}.ServeHTTP(w, w.req)
 		if c.hijacked() {
 			return
 		}
@@ -1248,6 +1259,32 @@ type Server struct {
 	WriteTimeout   time.Duration // maximum duration before timing out write of the response
 	MaxHeaderBytes int           // maximum size of request headers, DefaultMaxHeaderBytes if 0
 	TLSConfig      *tls.Config   // optional TLS config, used by ListenAndServeTLS
+
+	// TLSNextProto optionally specifies a function to take over
+	// ownership of the provided TLS connection when an NPN
+	// protocol upgrade has occured.  The map key is the protocol
+	// name negotiated. The Handler argument should be used to
+	// handle HTTP requests and will initialize the Request's TLS
+	// and RemoteAddr if not already set.  The connection is
+	// automatically closed when the function returns.
+	TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
+}
+
+// serverHandler delegates to either the server's Handler or
+// DefaultServeMux and also handles "OPTIONS *" requests.
+type serverHandler struct {
+	srv *Server
+}
+
+func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
+	handler := sh.srv.Handler
+	if handler == nil {
+		handler = DefaultServeMux
+	}
+	if req.RequestURI == "*" && req.Method == "OPTIONS" {
+		handler = globalOptionsHandler{}
+	}
+	handler.ServeHTTP(rw, req)
 }
 
 // ListenAndServe listens on the TCP network address srv.Addr and then
@@ -1504,6 +1541,31 @@ func (globalOptionsHandler) ServeHTTP(w ResponseWriter, r *Request) {
 	}
 }
 
+// eofReader is a non-nil io.ReadCloser that always returns EOF.
+var eofReader = ioutil.NopCloser(strings.NewReader(""))
+
+// initNPNRequest is an HTTP handler that initializes certain
+// uninitialized fields in its *Request. Such partially-initialized
+// Requests come from NPN protocol handlers.
+type initNPNRequest struct {
+	c *tls.Conn
+	h serverHandler
+}
+
+func (h initNPNRequest) ServeHTTP(rw ResponseWriter, req *Request) {
+	if req.TLS == nil {
+		req.TLS = &tls.ConnectionState{}
+		*req.TLS = h.c.ConnectionState()
+	}
+	if req.Body == nil {
+		req.Body = eofReader
+	}
+	if req.RemoteAddr == "" {
+		req.RemoteAddr = h.c.RemoteAddr().String()
+	}
+	h.h.ServeHTTP(rw, req)
+}
+
 // loggingConn is used for debugging.
 type loggingConn struct {
 	name string