-
Notifications
You must be signed in to change notification settings - Fork 350
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Enables HTTP/2 connections over cleartext TCP with Prior Knowledge (RFC 7540 3.4). The implementation is based on the golang.org/x/net/http2/h2c and workarounds several issues: * golang/go#38064 * golang/go#26682 See h2c package docs for details. Signed-off-by: Alexander Yastrebov <[email protected]>
- Loading branch information
1 parent
5bfba18
commit b019978
Showing
7 changed files
with
287 additions
and
23 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,157 @@ | ||
| // Copyright 2018 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 h2c implements the unencrypted "h2c" form of HTTP/2. | ||
| // | ||
| // The h2c protocol is the non-TLS version of HTTP/2 | ||
| // | ||
| // The implementation is based on the golang.org/x/net/http2/h2c | ||
| package h2c | ||
|
|
||
| import ( | ||
| "context" | ||
| "errors" | ||
| "io" | ||
| "net" | ||
| "net/http" | ||
| "strings" | ||
| "sync/atomic" | ||
| "time" | ||
|
|
||
| log "github.com/sirupsen/logrus" | ||
| "golang.org/x/net/http2" | ||
| ) | ||
|
|
||
| type Handler interface { | ||
| // Shutdown gracefully shuts down the handler by waiting | ||
| // indefinitely for h2c connections to close. | ||
| // If the provided context expires before the shutdown is complete, | ||
| // Shutdown returns the context's error. | ||
| // | ||
| // Shutdown should be called after http.Server Shutdown returns. | ||
| Shutdown(context.Context) error | ||
| } | ||
|
|
||
| type Options struct{} | ||
|
|
||
| type h2cHandler struct { | ||
| handler http.Handler | ||
| s1 *http.Server | ||
| s2 *http2.Server | ||
| conns int64 | ||
| } | ||
|
|
||
| // Enable creates an http2.Server s2, wraps http.Server s1 original handler | ||
| // with a handler intercepting any h2c traffic and registers s2 | ||
| // startGracefulShutdown on s1 Shutdown. It returns H2CHandler to be called | ||
| // after s1.Shutdown returns. | ||
| // | ||
| // If a request is an h2c connection, it is hijacked and redirected to the | ||
| // s2.ServeConn along with the original s1 handler. Otherwise the handler just | ||
| // forwards requests to the original s1 handler. This works because h2c is | ||
| // designed to be parsable as a valid HTTP/1, but ignored by any HTTP server | ||
| // that does not handle h2c. Therefore we leverage the HTTP/1 compatible parts | ||
| // of the Go http library to parse and recognize h2c requests. | ||
| // | ||
| // There are two ways to begin an h2c connection (RFC 7540 Section 3.2 and 3.4): | ||
| // (1) Starting with Prior Knowledge - this works by starting an h2c connection | ||
| // with a string of bytes that is valid HTTP/1, but unlikely to occur in | ||
| // practice and (2) Upgrading from HTTP/1 to h2c. | ||
| // | ||
| // This implementation workarounds several issues of the golang.org/x/net/http2/h2c: | ||
| // * drops support for upgrading from HTTP/1 to h2c, see https://github.com/golang/go/issues/38064 | ||
| // * implements graceful shutdown, see https://github.com/golang/go/issues/26682 | ||
| // * remove closing of the hijacked connection because s2.ServeConn closes it | ||
| // * removes buffered connection write | ||
| func Enable(s1 *http.Server, reserved *Options) Handler { | ||
| s2 := &http2.Server{} | ||
| h := &h2cHandler{handler: s1.Handler, s1: s1, s2: s2} | ||
|
|
||
| // register s2 startGracefulShutdown on s1 Shutdown | ||
| http2.ConfigureServer(s1, s2) | ||
| s1.Handler = h | ||
|
|
||
| return h | ||
| } | ||
|
|
||
| func (s *h2cHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { | ||
| // Handle h2c with prior knowledge (RFC 7540 Section 3.4) | ||
| if r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0" { | ||
| conn, err := initH2CWithPriorKnowledge(w) | ||
| if err != nil { | ||
| return | ||
| } | ||
| n := atomic.AddInt64(&s.conns, 1) | ||
| log.Debugf("h2c start: %d connections", n) | ||
|
|
||
| s.s2.ServeConn(conn, &http2.ServeConnOpts{Handler: s.handler, BaseConfig: s.s1}) | ||
|
|
||
| n = atomic.AddInt64(&s.conns, -1) | ||
| log.Debugf("h2c done: %d connections", n) | ||
| } else { | ||
| s.handler.ServeHTTP(w, r) | ||
| } | ||
| } | ||
|
|
||
| // initH2CWithPriorKnowledge implements creating an h2c connection with prior | ||
| // knowledge (Section 3.4) and creates a net.Conn suitable for http2.ServeConn. | ||
| // All we have to do is look for the client preface that is supposed to be a part | ||
| // of the body, and reforward the client preface on the net.Conn this function | ||
| // creates. | ||
| func initH2CWithPriorKnowledge(w http.ResponseWriter) (net.Conn, error) { | ||
| hijacker, ok := w.(http.Hijacker) | ||
| if !ok { | ||
| return nil, errors.New("hijack is not supported") | ||
| } | ||
| conn, rw, err := hijacker.Hijack() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| r := rw.Reader | ||
|
|
||
| const expectedBody = "SM\r\n\r\n" | ||
|
|
||
| buf := make([]byte, len(expectedBody)) | ||
| n, err := io.ReadFull(r, buf) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| if string(buf[:n]) == expectedBody { | ||
| return &h2cConn{ | ||
| Conn: conn, | ||
| Reader: io.MultiReader(strings.NewReader(http2.ClientPreface), r), | ||
| }, nil | ||
| } | ||
|
|
||
| conn.Close() | ||
| return nil, errors.New("invalid client preface") | ||
| } | ||
|
|
||
| func (s *h2cHandler) Shutdown(ctx context.Context) error { | ||
| timer := time.NewTicker(500 * time.Millisecond) | ||
| defer timer.Stop() | ||
| for { | ||
| n := atomic.LoadInt64(&s.conns) | ||
| log.Debugf("h2c close: %d connections", n) | ||
|
|
||
| if n == 0 { | ||
| return nil | ||
| } | ||
| select { | ||
| case <-ctx.Done(): | ||
| return ctx.Err() | ||
| case <-timer.C: | ||
| } | ||
| } | ||
| } | ||
|
|
||
| type h2cConn struct { | ||
| net.Conn | ||
| io.Reader | ||
| } | ||
|
|
||
| func (c *h2cConn) Read(p []byte) (int, error) { | ||
| return c.Reader.Read(p) | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.