diff options
Diffstat (limited to 'vendor/golang.org/x/net/http2/server.go')
| -rw-r--r-- | vendor/golang.org/x/net/http2/server.go | 2962 |
1 files changed, 2962 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/http2/server.go b/vendor/golang.org/x/net/http2/server.go new file mode 100644 index 00000000..bc9e41a1 --- /dev/null +++ b/vendor/golang.org/x/net/http2/server.go @@ -0,0 +1,2962 @@ +// Copyright 2014 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. + +// TODO: turn off the serve goroutine when idle, so +// an idle conn only has the readFrames goroutine active. (which could +// also be optimized probably to pin less memory in crypto/tls). This +// would involve tracking when the serve goroutine is active (atomic +// int32 read/CAS probably?) and starting it up when frames arrive, +// and shutting it down when all handlers exit. the occasional PING +// packets could use time.AfterFunc to call sc.wakeStartServeLoop() +// (which is a no-op if already running) and then queue the PING write +// as normal. The serve loop would then exit in most cases (if no +// Handlers running) and not be woken up again until the PING packet +// returns. + +// TODO (maybe): add a mechanism for Handlers to going into +// half-closed-local mode (rw.(io.Closer) test?) but not exit their +// handler, and continue to be able to read from the +// Request.Body. This would be a somewhat semantic change from HTTP/1 +// (or at least what we expose in net/http), so I'd probably want to +// add it there too. For now, this package says that returning from +// the Handler ServeHTTP function means you're both done reading and +// done writing, without a way to stop just one or the other. + +package http2 + +import ( + "bufio" + "bytes" + "context" + "crypto/tls" + "errors" + "fmt" + "io" + "log" + "math" + "net" + "net/http" + "net/textproto" + "net/url" + "os" + "reflect" + "runtime" + "strconv" + "strings" + "sync" + "time" + + "golang.org/x/net/http/httpguts" + "golang.org/x/net/http2/hpack" +) + +const ( + prefaceTimeout = 10 * time.Second + firstSettingsTimeout = 2 * time.Second // should be in-flight with preface anyway + handlerChunkWriteSize = 4 << 10 + defaultMaxStreams = 250 // TODO: make this 100 as the GFE seems to? + maxQueuedControlFrames = 10000 +) + +var ( + errClientDisconnected = errors.New("client disconnected") + errClosedBody = errors.New("body closed by handler") + errHandlerComplete = errors.New("http2: request body closed due to handler exiting") + errStreamClosed = errors.New("http2: stream closed") +) + +var responseWriterStatePool = sync.Pool{ + New: func() interface{} { + rws := &responseWriterState{} + rws.bw = bufio.NewWriterSize(chunkWriter{rws}, handlerChunkWriteSize) + return rws + }, +} + +// Test hooks. +var ( + testHookOnConn func() + testHookGetServerConn func(*serverConn) + testHookOnPanicMu *sync.Mutex // nil except in tests + testHookOnPanic func(sc *serverConn, panicVal interface{}) (rePanic bool) +) + +// Server is an HTTP/2 server. +type Server struct { + // MaxHandlers limits the number of http.Handler ServeHTTP goroutines + // which may run at a time over all connections. + // Negative or zero no limit. + // TODO: implement + MaxHandlers int + + // MaxConcurrentStreams optionally specifies the number of + // concurrent streams that each client may have open at a + // time. This is unrelated to the number of http.Handler goroutines + // which may be active globally, which is MaxHandlers. + // If zero, MaxConcurrentStreams defaults to at least 100, per + // the HTTP/2 spec's recommendations. + MaxConcurrentStreams uint32 + + // MaxReadFrameSize optionally specifies the largest frame + // this server is willing to read. A valid value is between + // 16k and 16M, inclusive. If zero or otherwise invalid, a + // default value is used. + MaxReadFrameSize uint32 + + // PermitProhibitedCipherSuites, if true, permits the use of + // cipher suites prohibited by the HTTP/2 spec. + PermitProhibitedCipherSuites bool + + // IdleTimeout specifies how long until idle clients should be + // closed with a GOAWAY frame. PING frames are not considered + // activity for the purposes of IdleTimeout. + IdleTimeout time.Duration + + // MaxUploadBufferPerConnection is the size of the initial flow + // control window for each connections. The HTTP/2 spec does not + // allow this to be smaller than 65535 or larger than 2^32-1. + // If the value is outside this range, a default value will be + // used instead. + MaxUploadBufferPerConnection int32 + + // MaxUploadBufferPerStream is the size of the initial flow control + // window for each stream. The HTTP/2 spec does not allow this to + // be larger than 2^32-1. If the value is zero or larger than the + // maximum, a default value will be used instead. + MaxUploadBufferPerStream int32 + + // NewWriteScheduler constructs a write scheduler for a connection. + // If nil, a default scheduler is chosen. + NewWriteScheduler func() WriteScheduler + + // Internal state. This is a pointer (rather than embedded directly) + // so that we don't embed a Mutex in this struct, which will make the + // struct non-copyable, which might break some callers. + state *serverInternalState +} + +func (s *Server) initialConnRecvWindowSize() int32 { + if s.MaxUploadBufferPerConnection > initialWindowSize { + return s.MaxUploadBufferPerConnection + } + return 1 << 20 +} + +func (s *Server) initialStreamRecvWindowSize() int32 { + if s.MaxUploadBufferPerStream > 0 { + return s.MaxUploadBufferPerStream + } + return 1 << 20 +} + +func (s *Server) maxReadFrameSize() uint32 { + if v := s.MaxReadFrameSize; v >= minMaxFrameSize && v <= maxFrameSize { + return v + } + return defaultMaxReadFrameSize +} + +func (s *Server) maxConcurrentStreams() uint32 { + if v := s.MaxConcurrentStreams; v > 0 { + return v + } + return defaultMaxStreams +} + +// maxQueuedControlFrames is the maximum number of control frames like +// SETTINGS, PING and RST_STREAM that will be queued for writing before +// the connection is closed to prevent memory exhaustion attacks. +func (s *Server) maxQueuedControlFrames() int { + // TODO: if anybody asks, add a Server field, and remember to define the + // behavior of negative values. + return maxQueuedControlFrames +} + +type serverInternalState struct { + mu sync.Mutex + activeConns map[*serverConn]struct{} +} + +func (s *serverInternalState) registerConn(sc *serverConn) { + if s == nil { + return // if the Server was used without calling ConfigureServer + } + s.mu.Lock() + s.activeConns[sc] = struct{}{} + s.mu.Unlock() +} + +func (s *serverInternalState) unregisterConn(sc *serverConn) { + if s == nil { + return // if the Server was used without calling ConfigureServer + } + s.mu.Lock() + delete(s.activeConns, sc) + s.mu.Unlock() +} + +func (s *serverInternalState) startGracefulShutdown() { + if s == nil { + return // if the Server was used without calling ConfigureServer + } + s.mu.Lock() + for sc := range s.activeConns { + sc.startGracefulShutdown() + } + s.mu.Unlock() +} + +// ConfigureServer adds HTTP/2 support to a net/http Server. +// +// The configuration conf may be nil. +// +// ConfigureServer must be called before s begins serving. +func ConfigureServer(s *http.Server, conf *Server) error { + if s == nil { + panic("nil *http.Server") + } + if conf == nil { + conf = new(Server) + } + conf.state = &serverInternalState{activeConns: make(map[*serverConn]struct{})} + if h1, h2 := s, conf; h2.IdleTimeout == 0 { + if h1.IdleTimeout != 0 { + h2.IdleTimeout = h1.IdleTimeout + } else { + h2.IdleTimeout = h1.ReadTimeout + } + } + s.RegisterOnShutdown(conf.state.startGracefulShutdown) + + if s.TLSConfig == nil { + s.TLSConfig = new(tls.Config) + } else if s.TLSConfig.CipherSuites != nil { + // If they already provided a CipherSuite list, return + // an error if it has a bad order or is missing + // ECDHE_RSA_WITH_AES_128_GCM_SHA256 or ECDHE_ECDSA_WITH_AES_128_GCM_SHA256. + haveRequired := false + sawBad := false + for i, cs := range s.TLSConfig.CipherSuites { + switch cs { + case tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, + // Alternative MTI cipher to not discourage ECDSA-only servers. + // See http://golang.org/cl/30721 for further information. + tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256: + haveRequired = true + } + if isBadCipher(cs) { + sawBad = true + } else if sawBad { + return fmt.Errorf("http2: TLSConfig.CipherSuites index %d contains an HTTP/2-approved cipher suite (%#04x), but it comes after unapproved cipher suites. With this configuration, clients that don't support previous, approved cipher suites may be given an unapproved one and reject the connection.", i, cs) + } + } + if !haveRequired { + return fmt.Errorf("http2: TLSConfig.CipherSuites is missing an HTTP/2-required AES_128_GCM_SHA256 cipher (need at least one of TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 or TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256).") + } + } + + // Note: not setting MinVersion to tls.VersionTLS12, + // as we don't want to interfere with HTTP/1.1 traffic + // on the user's server. We enforce TLS 1.2 later once + // we accept a connection. Ideally this should be done + // during next-proto selection, but using TLS <1.2 with + // HTTP/2 is still the client's bug. + + s.TLSConfig.PreferServerCipherSuites = true + + haveNPN := false + for _, p := range s.TLSConfig.NextProtos { + if p == NextProtoTLS { + haveNPN = true + break + } + } + if !haveNPN { + s.TLSConfig.NextProtos = append(s.TLSConfig.NextProtos, NextProtoTLS) + } + + if s.TLSNextProto == nil { + s.TLSNextProto = map[string]func(*http.Server, *tls.Conn, http.Handler){} + } + protoHandler := func(hs *http.Server, c *tls.Conn, h http.Handler) { + if testHookOnConn != nil { + testHookOnConn() + } + // The TLSNextProto interface predates contexts, so + // the net/http package passes down its per-connection + // base context via an exported but unadvertised + // method on the Handler. This is for internal + // net/http<=>http2 use only. + var ctx context.Context + type baseContexter interface { + BaseContext() context.Context + } + if bc, ok := h.(baseContexter); ok { + ctx = bc.BaseContext() + } + conf.ServeConn(c, &ServeConnOpts{ + Context: ctx, + Handler: h, + BaseConfig: hs, + }) + } + s.TLSNextProto[NextProtoTLS] = protoHandler + return nil +} + +// ServeConnOpts are options for the Server.ServeConn method. +type ServeConnOpts struct { + // Context is the base context to use. + // If nil, context.Background is used. + Context context.Context + + // BaseConfig optionally sets the base configuration + // for values. If nil, defaults are used. + BaseConfig *http.Server + + // Handler specifies which handler to use for processing + // requests. If nil, BaseConfig.Handler is used. If BaseConfig + // or BaseConfig.Handler is nil, http.DefaultServeMux is used. + Handler http.Handler +} + +func (o *ServeConnOpts) context() context.Context { + if o != nil && o.Context != nil { + return o.Context + } + return context.Background() +} + +func (o *ServeConnOpts) baseConfig() *http.Server { + if o != nil && o.BaseConfig != nil { + return o.BaseConfig + } + return new(http.Server) +} + +func (o *ServeConnOpts) handler() http.Handler { + if o != nil { + if o.Handler != nil { + return o.Handler + } + if o.BaseConfig != nil && o.BaseConfig.Handler != nil { + return o.BaseConfig.Handler + } + } + return http.DefaultServeMux +} + +// ServeConn serves HTTP/2 requests on the provided connection and +// blocks until the connection is no longer readable. +// +// ServeConn starts speaking HTTP/2 assuming that c has not had any +// reads or writes. It writes its initial settings frame and expects +// to be able to read the preface and settings frame from the +// client. If c has a ConnectionState method like a *tls.Conn, the +// ConnectionState is used to verify the TLS ciphersuite and to set +// the Request.TLS field in Handlers. +// +// ServeConn does not support h2c by itself. Any h2c support must be +// implemented in terms of providing a suitably-behaving net.Conn. +// +// The opts parameter is optional. If nil, default values are used. +func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) { + baseCtx, cancel := serverConnBaseContext(c, opts) + defer cancel() + + sc := &serverConn{ + srv: s, + hs: opts.baseConfig(), + conn: c, + baseCtx: baseCtx, + remoteAddrStr: c.RemoteAddr().String(), + bw: newBufferedWriter(c), + handler: opts.handler(), + streams: make(map[uint32]*stream), + readFrameCh: make(chan readFrameResult), + wantWriteFrameCh: make(chan FrameWriteRequest, 8), + serveMsgCh: make(chan interface{}, 8), + wroteFrameCh: make(chan frameWriteResult, 1), // buffered; one send in writeFrameAsync + bodyReadCh: make(chan bodyReadMsg), // buffering doesn't matter either way + doneServing: make(chan struct{}), + clientMaxStreams: math.MaxUint32, // Section 6.5.2: "Initially, there is no limit to this value" + advMaxStreams: s.maxConcurrentStreams(), + initialStreamSendWindowSize: initialWindowSize, + maxFrameSize: initialMaxFrameSize, + headerTableSize: initialHeaderTableSize, + serveG: newGoroutineLock(), + pushEnabled: true, + } + + s.state.registerConn(sc) + defer s.state.unregisterConn(sc) + + // The net/http package sets the write deadline from the + // http.Server.WriteTimeout during the TLS handshake, but then + // passes the connection off to us with the deadline already set. + // Write deadlines are set per stream in serverConn.newStream. + // Disarm the net.Conn write deadline here. + if sc.hs.WriteTimeout != 0 { + sc.conn.SetWriteDeadline(time.Time{}) + } + + if s.NewWriteScheduler != nil { + sc.writeSched = s.NewWriteScheduler() + } else { + sc.writeSched = NewRandomWriteScheduler() + } + + // These start at the RFC-specified defaults. If there is a higher + // configured value for inflow, that will be updated when we send a + // WINDOW_UPDATE shortly after sending SETTINGS. + sc.flow.add(initialWindowSize) + sc.inflow.add(initialWindowSize) + sc.hpackEncoder = hpack.NewEncoder(&sc.headerWriteBuf) + + fr := NewFramer(sc.bw, c) + fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil) + fr.MaxHeaderListSize = sc.maxHeaderListSize() + fr.SetMaxReadFrameSize(s.maxReadFrameSize()) + sc.framer = fr + + if tc, ok := c.(connectionStater); ok { + sc.tlsState = new(tls.ConnectionState) + *sc.tlsState = tc.ConnectionState() + // 9.2 Use of TLS Features + // An implementation of HTTP/2 over TLS MUST use TLS + // 1.2 or higher with the restrictions on feature set + // and cipher suite described in this section. Due to + // implementation limitations, it might not be + // possible to fail TLS negotiation. An endpoint MUST + // immediately terminate an HTTP/2 connection that + // does not meet the TLS requirements described in + // this section with a connection error (Section + // 5.4.1) of type INADEQUATE_SECURITY. + if sc.tlsState.Version < tls.VersionTLS12 { + sc.rejectConn(ErrCodeInadequateSecurity, "TLS version too low") + return + } + + if sc.tlsState.ServerName == "" { + // Client must use SNI, but we don't enforce that anymore, + // since it was causing problems when connecting to bare IP + // addresses during development. + // + // TODO: optionally enforce? Or enforce at the time we receive + // a new request, and verify the ServerName matches the :authority? + // But that precludes proxy situations, perhaps. + // + // So for now, do nothing here again. + } + + if !s.PermitProhibitedCipherSuites && isBadCipher(sc.tlsState.CipherSuite) { + // "Endpoints MAY choose to generate a connection error + // (Section 5.4.1) of type INADEQUATE_SECURITY if one of + // the prohibited cipher suites are negotiated." + // + // We choose that. In my opinion, the spec is weak + // here. It also says both parties must support at least + // TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 so there's no + // excuses here. If we really must, we could allow an + // "AllowInsecureWeakCiphers" option on the server later. + // Let's see how it plays out first. + sc.rejectConn(ErrCodeInadequateSecurity, fmt.Sprintf("Prohibited TLS 1.2 Cipher Suite: %x", sc.tlsState.CipherSuite)) + return + } + } + + if hook := testHookGetServerConn; hook != nil { + hook(sc) + } + sc.serve() +} + +func serverConnBaseContext(c net.Conn, opts *ServeConnOpts) (ctx context.Context, cancel func()) { + ctx, cancel = context.WithCancel(opts.context()) + ctx = context.WithValue(ctx, http.LocalAddrContextKey, c.LocalAddr()) + if hs := opts.baseConfig(); hs != nil { + ctx = context.WithValue(ctx, http.ServerContextKey, hs) + } + return +} + +func (sc *serverConn) rejectConn(err ErrCode, debug string) { + sc.vlogf("http2: server rejecting conn: %v, %s", err, debug) + // ignoring errors. hanging up anyway. + sc.framer.WriteGoAway(0, err, []byte(debug)) + sc.bw.Flush() + sc.conn.Close() +} + +type serverConn struct { + // Immutable: + srv *Server + hs *http.Server + conn net.Conn + bw *bufferedWriter // writing to conn + handler http.Handler + baseCtx context.Context + framer *Framer + doneServing chan struct{} // closed when serverConn.serve ends + readFrameCh chan readFrameResult // written by serverConn.readFrames + wantWriteFrameCh chan FrameWriteRequest // from handlers -> serve + wroteFrameCh chan frameWriteResult // from writeFrameAsync -> serve, tickles more frame writes + bodyReadCh chan bodyReadMsg // from handlers -> serve + serveMsgCh chan interface{} // misc messages & code to send to / run on the serve loop + flow flow // conn-wide (not stream-specific) outbound flow control + inflow flow // conn-wide inbound flow control + tlsState *tls.ConnectionState // shared by all handlers, like net/http + remoteAddrStr string + writeSched WriteScheduler + + // Everything following is owned by the serve loop; use serveG.check(): + serveG goroutineLock // used to verify funcs are on serve() + pushEnabled bool + sawFirstSettings bool // got the initial SETTINGS frame after the preface + needToSendSettingsAck bool + unackedSettings int // how many SETTINGS have we sent without ACKs? + queuedControlFrames int // control frames in the writeSched queue + clientMaxStreams uint32 // SETTINGS_MAX_CONCURRENT_STREAMS from client (our PUSH_PROMISE limit) + advMaxStreams uint32 // our SETTINGS_MAX_CONCURRENT_STREAMS advertised the client + curClientStreams uint32 // number of open streams initiated by the client + curPushedStreams uint32 // number of open streams initiated by server push + maxClientStreamID uint32 // max ever seen from client (odd), or 0 if there have been no client requests + maxPushPromiseID uint32 // ID of the last push promise (even), or 0 if there have been no pushes + streams map[uint32]*stream + initialStreamSendWindowSize int32 + maxFrameSize int32 + headerTableSize uint32 + peerMaxHeaderListSize uint32 // zero means unknown (default) + canonHeader map[string]string // http2-lower-case -> Go-Canonical-Case + writingFrame bool // started writing a frame (on serve goroutine or separate) + writingFrameAsync bool // started a frame on its own goroutine but haven't heard back on wroteFrameCh + needsFrameFlush bool // last frame write wasn't a flush + inGoAway bool // we've started to or sent GOAWAY + inFrameScheduleLoop bool // whether we're in the scheduleFrameWrite loop + needToSendGoAway bool // we need to schedule a GOAWAY frame write + goAwayCode ErrCode + shutdownTimer *time.Timer // nil until used + idleTimer *time.Timer // nil if unused + + // Owned by the writeFrameAsync goroutine: + headerWriteBuf bytes.Buffer + hpackEncoder *hpack.Encoder + + // Used by startGracefulShutdown. + shutdownOnce sync.Once +} + +func (sc *serverConn) maxHeaderListSize() uint32 { + n := sc.hs.MaxHeaderBytes + if n <= 0 { + n = http.DefaultMaxHeaderBytes + } + // http2's count is in a slightly different unit and includes 32 bytes per pair. + // So, take the net/http.Server value and pad it up a bit, assuming 10 headers. + const perFieldOverhead = 32 // per http2 spec + const typicalHeaders = 10 // conservative + return uint32(n + typicalHeaders*perFieldOverhead) +} + +func (sc *serverConn) curOpenStreams() uint32 { + sc.serveG.check() + return sc.curClientStreams + sc.curPushedStreams +} + +// stream represents a stream. This is the minimal metadata needed by +// the serve goroutine. Most of the actual stream state is owned by +// the http.Handler's goroutine in the responseWriter. Because the +// responseWriter's responseWriterState is recycled at the end of a +// handler, this struct intentionally has no pointer to the +// *responseWriter{,State} itself, as the Handler ending nils out the +// responseWriter's state field. +type stream struct { + // immutable: + sc *serverConn + id uint32 + body *pipe // non-nil if expecting DATA frames + cw closeWaiter // closed wait stream transitions to closed state + ctx context.Context + cancelCtx func() + + // owned by serverConn's serve loop: + bodyBytes int64 // body bytes seen so far + declBodyBytes int64 // or -1 if undeclared + flow flow // limits writing from Handler to client + inflow flow // what the client is allowed to POST/etc to us + state streamState + resetQueued bool // RST_STREAM queued for write; set by sc.resetStream + gotTrailerHeader bool // HEADER frame for trailers was seen + wroteHeaders bool // whether we wrote headers (not status 100) + writeDeadline *time.Timer // nil if unused + + trailer http.Header // accumulated trailers + reqTrailer http.Header // handler's Request.Trailer +} + +func (sc *serverConn) Framer() *Framer { return sc.framer } +func (sc *serverConn) CloseConn() error { return sc.conn.Close() } +func (sc *serverConn) Flush() error { return sc.bw.Flush() } +func (sc *serverConn) HeaderEncoder() (*hpack.Encoder, *bytes.Buffer) { + return sc.hpackEncoder, &sc.headerWriteBuf +} + +func (sc *serverConn) state(streamID uint32) (streamState, *stream) { + sc.serveG.check() + // http://tools.ietf.org/html/rfc7540#section-5.1 + if st, ok := sc.streams[streamID]; ok { + return st.state, st + } + // "The first use of a new stream identifier implicitly closes all + // streams in the "idle" state that might have been initiated by + // that peer with a lower-valued stream identifier. For example, if + // a client sends a HEADERS frame on stream 7 without ever sending a + // frame on stream 5, then stream 5 transitions to the "closed" + // state when the first frame for stream 7 is sent or received." + if streamID%2 == 1 { + if streamID <= sc.maxClientStreamID { + return stateClosed, nil + } + } else { + if streamID <= sc.maxPushPromiseID { + return stateClosed, nil + } + } + return stateIdle, nil +} + +// setConnState calls the net/http ConnState hook for this connection, if configured. +// Note that the net/http package does StateNew and StateClosed for us. +// There is currently no plan for StateHijacked or hijacking HTTP/2 connections. +func (sc *serverConn) setConnState(state http.ConnState) { + if sc.hs.ConnState != nil { + sc.hs.ConnState(sc.conn, state) + } +} + +func (sc *serverConn) vlogf(format string, args ...interface{}) { + if VerboseLogs { + sc.logf(format, args...) + } +} + +func (sc *serverConn) logf(format string, args ...interface{}) { + if lg := sc.hs.ErrorLog; lg != nil { + lg.Printf(format, args...) + } else { + log.Printf(format, args...) + } +} + +// errno returns v's underlying uintptr, else 0. +// +// TODO: remove this helper function once http2 can use build +// tags. See comment in isClosedConnError. +func errno(v error) uintptr { + if rv := reflect.ValueOf(v); rv.Kind() == reflect.Uintptr { + return uintptr(rv.Uint()) + } + return 0 +} + +// isClosedConnError reports whether err is an error from use of a closed +// network connection. +func isClosedConnError(err error) bool { + if err == nil { + return false + } + + // TODO: remove this string search and be more like the Windows + // case below. That might involve modifying the standard library + // to return better error types. + str := err.Error() + if strings.Contains(str, "use of closed network connection") { + return true + } + + // TODO(bradfitz): x/tools/cmd/bundle doesn't really support + // build tags, so I can't make an http2_windows.go file with + // Windows-specific stuff. Fix that and move this, once we + // have a way to bundle this into std's net/http somehow. + if runtime.GOOS == "windows" { + if oe, ok := err.(*net.OpError); ok && oe.Op == "read" { + if se, ok := oe.Err.(*os.SyscallError); ok && se.Syscall == "wsarecv" { + const WSAECONNABORTED = 10053 + const WSAECONNRESET = 10054 + if n := errno(se.Err); n == WSAECONNRESET || n == WSAECONNABORTED { + return true + } + } + } + } + return false +} + +func (sc *serverConn) condlogf(err error, format string, args ...interface{}) { + if err == nil { + return + } + if err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err) || err == errPrefaceTimeout { + // Boring, expected errors. + sc.vlogf(format, args...) + } else { + sc.logf(format, args...) + } +} + +func (sc *serverConn) canonicalHeader(v string) string { + sc.serveG.check() + buildCommonHeaderMapsOnce() + cv, ok := commonCanonHeader[v] + if ok { + return cv + } + cv, ok = sc.canonHeader[v] + if ok { + return cv + } + if sc.canonHeader == nil { + sc.canonHeader = make(map[string]string) + } + cv = http.CanonicalHeaderKey(v) + sc.canonHeader[v] = cv + return cv +} + +type readFrameResult struct { + f Frame // valid until readMore is called + err error + + // readMore should be called once the consumer no longer needs or + // retains f. After readMore, f is invalid and more frames can be + // read. + readMore func() +} + +// readFrames is the loop that reads incoming frames. +// It takes care to only read one frame at a time, blocking until the +// consumer is done with the frame. +// It's run on its own goroutine. +func (sc *serverConn) readFrames() { + gate := make(gate) + gateDone := gate.Done + for { + f, err := sc.framer.ReadFrame() + select { + case sc.readFrameCh <- readFrameResult{f, err, gateDone}: + case <-sc.doneServing: + return + } + select { + case <-gate: + case <-sc.doneServing: + return + } + if terminalReadFrameError(err) { + return + } + } +} + +// frameWriteResult is the message passed from writeFrameAsync to the serve goroutine. +type frameWriteResult struct { + wr FrameWriteRequest // what was written (or attempted) + err error // result of the writeFrame call +} + +// writeFrameAsync runs in its own goroutine and writes a single frame +// and then reports when it's done. +// At most one goroutine can be running writeFrameAsync at a time per +// serverConn. +func (sc *serverConn) writeFrameAsync(wr FrameWriteRequest) { + err := wr.write.writeFrame(sc) + sc.wroteFrameCh <- frameWriteResult{wr, err} +} + +func (sc *serverConn) closeAllStreamsOnConnClose() { + sc.serveG.check() + for _, st := range sc.streams { + sc.closeStream(st, errClientDisconnected) + } +} + +func (sc *serverConn) stopShutdownTimer() { + sc.serveG.check() + if t := sc.shutdownTimer; t != nil { + t.Stop() + } +} + +func (sc *serverConn) notePanic() { + // Note: this is for serverConn.serve panicking, not http.Handler code. + if testHookOnPanicMu != nil { + testHookOnPanicMu.Lock() + defer testHookOnPanicMu.Unlock() + } + if testHookOnPanic != nil { + if e := recover(); e != nil { + if testHookOnPanic(sc, e) { + panic(e) + } + } + } +} + +func (sc *serverConn) serve() { + sc.serveG.check() + defer sc.notePanic() + defer sc.conn.Close() + defer sc.closeAllStreamsOnConnClose() + defer sc.stopShutdownTimer() + defer close(sc.doneServing) // unblocks handlers trying to send + + if VerboseLogs { + sc.vlogf("http2: server connection from %v on %p", sc.conn.RemoteAddr(), sc.hs) + } + + sc.writeFrame(FrameWriteRequest{ + write: writeSettings{ + {SettingMaxFrameSize, sc.srv.maxReadFrameSize()}, + {SettingMaxConcurrentStreams, sc.advMaxStreams}, + {SettingMaxHeaderListSize, sc.maxHeaderListSize()}, + {SettingInitialWindowSize, uint32(sc.srv.initialStreamRecvWindowSize())}, + }, + }) + sc.unackedSettings++ + + // Each connection starts with intialWindowSize inflow tokens. + // If a higher value is configured, we add more tokens. + if diff := sc.srv.initialConnRecvWindowSize() - initialWindowSize; diff > 0 { + sc.sendWindowUpdate(nil, int(diff)) + } + + if err := sc.readPreface(); err != nil { + sc.condlogf(err, "http2: server: error reading preface from client %v: %v", sc.conn.RemoteAddr(), err) + return + } + // Now that we've got the preface, get us out of the + // "StateNew" state. We can't go directly to idle, though. + // Active means we read some data and anticipate a request. We'll + // do another Active when we get a HEADERS frame. + sc.setConnState(http.StateActive) + sc.setConnState(http.StateIdle) + + if sc.srv.IdleTimeout != 0 { + sc.idleTimer = time.AfterFunc(sc.srv.IdleTimeout, sc.onIdleTimer) + defer sc.idleTimer.Stop() + } + + go sc.readFrames() // closed by defer sc.conn.Close above + + settingsTimer := time.AfterFunc(firstSettingsTimeout, sc.onSettingsTimer) + defer settingsTimer.Stop() + + loopNum := 0 + for { + loopNum++ + select { + case wr := <-sc.wantWriteFrameCh: + if se, ok := wr.write.(StreamError); ok { + sc.resetStream(se) + break + } + sc.writeFrame(wr) + case res := <-sc.wroteFrameCh: + sc.wroteFrame(res) + case res := <-sc.readFrameCh: + if !sc.processFrameFromReader(res) { + return + } + res.readMore() + if settingsTimer != nil { + settingsTimer.Stop() + settingsTimer = nil + } + case m := <-sc.bodyReadCh: + sc.noteBodyRead(m.st, m.n) + case msg := <-sc.serveMsgCh: + switch v := msg.(type) { + case func(int): + v(loopNum) // for testing + case *serverMessage: + switch v { + case settingsTimerMsg: + sc.logf("timeout waiting for SETTINGS frames from %v", sc.conn.RemoteAddr()) + return + case idleTimerMsg: + sc.vlogf("connection is idle") + sc.goAway(ErrCodeNo) + case shutdownTimerMsg: + sc.vlogf("GOAWAY close timer fired; closing conn from %v", sc.conn.RemoteAddr()) + return + case gracefulShutdownMsg: + sc.startGracefulShutdownInternal() + default: + panic("unknown timer") + } + case *startPushRequest: + sc.startPush(v) + default: + panic(fmt.Sprintf("unexpected type %T", v)) + } + } + + // If the peer is causing us to generate a lot of control frames, + // but not reading them from us, assume they are trying to make us + // run out of memory. + if sc.queuedControlFrames > sc.srv.maxQueuedControlFrames() { + sc.vlogf("http2: too many control frames in send queue, closing connection") + return + } + + // Start the shutdown timer after sending a GOAWAY. When sending GOAWAY + // with no error code (graceful shutdown), don't start the timer until + // all open streams have been completed. + sentGoAway := sc.inGoAway && !sc.needToSendGoAway && !sc.writingFrame + gracefulShutdownComplete := sc.goAwayCode == ErrCodeNo && sc.curOpenStreams() == 0 + if sentGoAway && sc.shutdownTimer == nil && (sc.goAwayCode != ErrCodeNo || gracefulShutdownComplete) { + sc.shutDownIn(goAwayTimeout) + } + } +} + +func (sc *serverConn) awaitGracefulShutdown(sharedCh <-chan struct{}, privateCh chan struct{}) { + select { + case <-sc.doneServing: + case <-sharedCh: + close(privateCh) + } +} + +type serverMessage int + +// Message values sent to serveMsgCh. +var ( + settingsTimerMsg = new(serverMessage) + idleTimerMsg = new(serverMessage) + shutdownTimerMsg = new(serverMessage) + gracefulShutdownMsg = new(serverMessage) +) + +func (sc *serverConn) onSettingsTimer() { sc.sendServeMsg(settingsTimerMsg) } +func (sc *serverConn) onIdleTimer() { sc.sendServeMsg(idleTimerMsg) } +func (sc *serverConn) onShutdownTimer() { sc.sendServeMsg(shutdownTimerMsg) } + +func (sc *serverConn) sendServeMsg(msg interface{}) { + sc.serveG.checkNotOn() // NOT + select { + case sc.serveMsgCh <- msg: + case <-sc.doneServing: + } +} + +var errPrefaceTimeout = errors.New("timeout waiting for client preface") + +// readPreface reads the ClientPreface greeting from the peer or +// returns errPrefaceTimeout on timeout, or an error if the greeting +// is invalid. +func (sc *serverConn) readPreface() error { + errc := make(chan error, 1) + go func() { + // Read the client preface + buf := make([]byte, len(ClientPreface)) + if _, err := io.ReadFull(sc.conn, buf); err != nil { + errc <- err + } else if !bytes.Equal(buf, clientPreface) { + errc <- fmt.Errorf("bogus greeting %q", buf) + } else { + errc <- nil + } + }() + timer := time.NewTimer(prefaceTimeout) // TODO: configurable on *Server? + defer timer.Stop() + select { + case <-timer.C: + return errPrefaceTimeout + case err := <-errc: + if err == nil { + if VerboseLogs { + sc.vlogf("http2: server: client %v said hello", sc.conn.RemoteAddr()) + } + } + return err + } +} + +var errChanPool = sync.Pool{ + New: func() interface{} { return make(chan error, 1) }, +} + +var writeDataPool = sync.Pool{ + New: func() interface{} { return new(writeData) }, +} + +// writeDataFromHandler writes DATA response frames from a handler on +// the given stream. +func (sc *serverConn) writeDataFromHandler(stream *stream, data []byte, endStream bool) error { + ch := errChanPool.Get().(chan error) + writeArg := writeDataPool.Get().(*writeData) + *writeArg = writeData{stream.id, data, endStream} + err := sc.writeFrameFromHandler(FrameWriteRequest{ + write: writeArg, + stream: stream, + done: ch, + }) + if err != nil { + return err + } + var frameWriteDone bool // the frame write is done (successfully or not) + select { + case err = <-ch: + frameWriteDone = true + case <-sc.doneServing: + return errClientDisconnected + case <-stream.cw: + // If both ch and stream.cw were ready (as might + // happen on the final Write after an http.Handler + // ends), prefer the write result. Otherwise this + // might just be us successfully closing the stream. + // The writeFrameAsync and serve goroutines guarantee + // that the ch send will happen before the stream.cw + // close. + select { + case err = <-ch: + frameWriteDone = true + default: + return errStreamClosed + } + } + errChanPool.Put(ch) + if frameWriteDone { + writeDataPool.Put(writeArg) + } + return err +} + +// writeFrameFromHandler sends wr to sc.wantWriteFrameCh, but aborts +// if the connection has gone away. +// +// This must not be run from the serve goroutine itself, else it might +// deadlock writing to sc.wantWriteFrameCh (which is only mildly +// buffered and is read by serve itself). If you're on the serve +// goroutine, call writeFrame instead. +func (sc *serverConn) writeFrameFromHandler(wr FrameWriteRequest) error { + sc.serveG.checkNotOn() // NOT + select { + case sc.wantWriteFrameCh <- wr: + return nil + case <-sc.doneServing: + // Serve loop is gone. + // Client has closed their connection to the server. + return errClientDisconnected + } +} + +// writeFrame schedules a frame to write and sends it if there's nothing +// already being written. +// +// There is no pushback here (the serve goroutine never blocks). It's +// the http.Handlers that block, waiting for their previous frames to +// make it onto the wire +// +// If you're not on the serve goroutine, use writeFrameFromHandler instead. +func (sc *serverConn) writeFrame(wr FrameWriteRequest) { + sc.serveG.check() + + // If true, wr will not be written and wr.done will not be signaled. + var ignoreWrite bool + + // We are not allowed to write frames on closed streams. RFC 7540 Section + // 5.1.1 says: "An endpoint MUST NOT send frames other than PRIORITY on + // a closed stream." Our server never sends PRIORITY, so that exception + // does not apply. + // + // The serverConn might close an open stream while the stream's handler + // is still running. For example, the server might close a stream when it + // receives bad data from the client. If this happens, the handler might + // attempt to write a frame after the stream has been closed (since the + // handler hasn't yet been notified of the close). In this case, we simply + // ignore the frame. The handler will notice that the stream is closed when + // it waits for the frame to be written. + // + // As an exception to this rule, we allow sending RST_STREAM after close. + // This allows us to immediately reject new streams without tracking any + // state for those streams (except for the queued RST_STREAM frame). This + // may result in duplicate RST_STREAMs in some cases, but the client should + // ignore those. + if wr.StreamID() != 0 { + _, isReset := wr.write.(StreamError) + if state, _ := sc.state(wr.StreamID()); state == stateClosed && !isReset { + ignoreWrite = true + } + } + + // Don't send a 100-continue response if we've already sent headers. + // See golang.org/issue/14030. + switch wr.write.(type) { + case *writeResHeaders: + wr.stream.wroteHeaders = true + case write100ContinueHeadersFrame: + if wr.stream.wroteHeaders { + // We do not need to notify wr.done because this frame is + // never written with wr.done != nil. + if wr.done != nil { + panic("wr.done != nil for write100ContinueHeadersFrame") + } + ignoreWrite = true + } + } + + if !ignoreWrite { + if wr.isControl() { + sc.queuedControlFrames++ + // For extra safety, detect wraparounds, which should not happen, + // and pull the plug. + if sc.queuedControlFrames < 0 { + sc.conn.Close() + } + } + sc.writeSched.Push(wr) + } + sc.scheduleFrameWrite() +} + +// startFrameWrite starts a goroutine to write wr (in a separate +// goroutine since that might block on the network), and updates the +// serve goroutine's state about the world, updated from info in wr. +func (sc *serverConn) startFrameWrite(wr FrameWriteRequest) { + sc.serveG.check() + if sc.writingFrame { + panic("internal error: can only be writing one frame at a time") + } + + st := wr.stream + if st != nil { + switch st.state { + case stateHalfClosedLocal: + switch wr.write.(type) { + case StreamError, handlerPanicRST, writeWindowUpdate: + // RFC 7540 Section 5.1 allows sending RST_STREAM, PRIORITY, and WINDOW_UPDATE + // in this state. (We never send PRIORITY from the server, so that is not checked.) + default: + panic(fmt.Sprintf("internal error: attempt to send frame on a half-closed-local stream: %v", wr)) + } + case stateClosed: + panic(fmt.Sprintf("internal error: attempt to send frame on a closed stream: %v", wr)) + } + } + if wpp, ok := wr.write.(*writePushPromise); ok { + var err error + wpp.promisedID, err = wpp.allocatePromisedID() + if err != nil { + sc.writingFrameAsync = false + wr.replyToWriter(err) + return + } + } + + sc.writingFrame = true + sc.needsFrameFlush = true + if wr.write.staysWithinBuffer(sc.bw.Available()) { + sc.writingFrameAsync = false + err := wr.write.writeFrame(sc) + sc.wroteFrame(frameWriteResult{wr, err}) + } else { + sc.writingFrameAsync = true + go sc.writeFrameAsync(wr) + } +} + +// errHandlerPanicked is the error given to any callers blocked in a read from +// Request.Body when the main goroutine panics. Since most handlers read in the +// main ServeHTTP goroutine, this will show up rarely. +var errHandlerPanicked = errors.New("http2: handler panicked") + +// wroteFrame is called on the serve goroutine with the result of +// whatever happened on writeFrameAsync. +func (sc *serverConn) wroteFrame(res frameWriteResult) { + sc.serveG.check() + if !sc.writingFrame { + panic("internal error: expected to be already writing a frame") + } + sc.writingFrame = false + sc.writingFrameAsync = false + + wr := res.wr + + if writeEndsStream(wr.write) { + st := wr.stream + if st == nil { + panic("internal error: expecting non-nil stream") + } + switch st.state { + case stateOpen: + // Here we would go to stateHalfClosedLocal in + // theory, but since our handler is done and + // the net/http package provides no mechanism + // for closing a ResponseWriter while still + // reading data (see possible TODO at top of + // this file), we go into closed state here + // anyway, after telling the peer we're + // hanging up on them. We'll transition to + // stateClosed after the RST_STREAM frame is + // written. + st.state = stateHalfClosedLocal + // Section 8.1: a server MAY request that the client abort + // transmission of a request without error by sending a + // RST_STREAM with an error code of NO_ERROR after sending + // a complete response. + sc.resetStream(streamError(st.id, ErrCodeNo)) + case stateHalfClosedRemote: + sc.closeStream(st, errHandlerComplete) + } + } else { + switch v := wr.write.(type) { + case StreamError: + // st may be unknown if the RST_STREAM was generated to reject bad input. + if st, ok := sc.streams[v.StreamID]; ok { + sc.closeStream(st, v) + } + case handlerPanicRST: + sc.closeStream(wr.stream, errHandlerPanicked) + } + } + + // Reply (if requested) to unblock the ServeHTTP goroutine. + wr.replyToWriter(res.err) + + sc.scheduleFrameWrite() +} + +// scheduleFrameWrite tickles the frame writing scheduler. +// +// If a frame is already being written, nothing happens. This will be called again +// when the frame is done being written. +// +// If a frame isn't being written and we need to send one, the best frame +// to send is selected by writeSched. +// +// If a frame isn't being written and there's nothing else to send, we +// flush the write buffer. +func (sc *serverConn) scheduleFrameWrite() { + sc.serveG.check() + if sc.writingFrame || sc.inFrameScheduleLoop { + return + } + sc.inFrameScheduleLoop = true + for !sc.writingFrameAsync { + if sc.needToSendGoAway { + sc.needToSendGoAway = false + sc.startFrameWrite(FrameWriteRequest{ + write: &writeGoAway{ + maxStreamID: sc.maxClientStreamID, + code: sc.goAwayCode, + }, + }) + continue + } + if sc.needToSendSettingsAck { + sc.needToSendSettingsAck = false + sc.startFrameWrite(FrameWriteRequest{write: writeSettingsAck{}}) + continue + } + if !sc.inGoAway || sc.goAwayCode == ErrCodeNo { + if wr, ok := sc.writeSched.Pop(); ok { + if wr.isControl() { + sc.queuedControlFrames-- + } + sc.startFrameWrite(wr) + continue + } + } + if sc.needsFrameFlush { + sc.startFrameWrite(FrameWriteRequest{write: flushFrameWriter{}}) + sc.needsFrameFlush = false // after startFrameWrite, since it sets this true + continue + } + break + } + sc.inFrameScheduleLoop = false +} + +// startGracefulShutdown gracefully shuts down a connection. This +// sends GOAWAY with ErrCodeNo to tell the client we're gracefully +// shutting down. The connection isn't closed until all current +// streams are done. +// +// startGracefulShutdown returns immediately; it does not wait until +// the connection has shut down. +func (sc *serverConn) startGracefulShutdown() { + sc.serveG.checkNotOn() // NOT + sc.shutdownOnce.Do(func() { sc.sendServeMsg(gracefulShutdownMsg) }) +} + +// After sending GOAWAY, the connection will close after goAwayTimeout. +// If we close the connection immediately after sending GOAWAY, there may +// be unsent data in our kernel receive buffer, which will cause the kernel +// to send a TCP RST on close() instead of a FIN. This RST will abort the +// connection immediately, whether or not the client had received the GOAWAY. +// +// Ideally we should delay for at least 1 RTT + epsilon so the client has +// a chance to read the GOAWAY and stop sending messages. Measuring RTT +// is hard, so we approximate with 1 second. See golang.org/issue/18701. +// +// This is a var so it can be shorter in tests, where all requests uses the +// loopback interface making the expected RTT very small. +// +// TODO: configurable? +var goAwayTimeout = 1 * time.Second + +func (sc *serverConn) startGracefulShutdownInternal() { + sc.goAway(ErrCodeNo) +} + +func (sc *serverConn) goAway(code ErrCode) { + sc.serveG.check() + if sc.inGoAway { + return + } + sc.inGoAway = true + sc.needToSendGoAway = true + sc.goAwayCode = code + sc.scheduleFrameWrite() +} + +func (sc *serverConn) shutDownIn(d time.Duration) { + sc.serveG.check() + sc.shutdownTimer = time.AfterFunc(d, sc.onShutdownTimer) +} + +func (sc *serverConn) resetStream(se StreamError) { + sc.serveG.check() + sc.writeFrame(FrameWriteRequest{write: se}) + if st, ok := sc.streams[se.StreamID]; ok { + st.resetQueued = true + } +} + +// processFrameFromReader processes the serve loop's read from readFrameCh from the +// frame-reading goroutine. +// processFrameFromReader returns whether the connection should be kept open. +func (sc *serverConn) processFrameFromReader(res readFrameResult) bool { + sc.serveG.check() + err := res.err + if err != nil { + if err == ErrFrameTooLarge { + sc.goAway(ErrCodeFrameSize) + return true // goAway will close the loop + } + clientGone := err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err) + if clientGone { + // TODO: could we also get into this state if + // the peer does a half close + // (e.g. CloseWrite) because they're done + // sending frames but they're still wanting + // our open replies? Investigate. + // TODO: add CloseWrite to crypto/tls.Conn first + // so we have a way to test this? I suppose + // just for testing we could have a non-TLS mode. + return false + } + } else { + f := res.f + if VerboseLogs { + sc.vlogf("http2: server read frame %v", summarizeFrame(f)) + } + err = sc.processFrame(f) + if err == nil { + return true + } + } + + switch ev := err.(type) { + case StreamError: + sc.resetStream(ev) + return true + case goAwayFlowError: + sc.goAway(ErrCodeFlowControl) + return true + case ConnectionError: + sc.logf("http2: server connection error from %v: %v", sc.conn.RemoteAddr(), ev) + sc.goAway(ErrCode(ev)) + return true // goAway will handle shutdown + default: + if res.err != nil { + sc.vlogf("http2: server closing client connection; error reading frame from client %s: %v", sc.conn.RemoteAddr(), err) + } else { + sc.logf("http2: server closing client connection: %v", err) + } + return false + } +} + +func (sc *serverConn) processFrame(f Frame) error { + sc.serveG.check() + + // First frame received must be SETTINGS. + if !sc.sawFirstSettings { + if _, ok := f.(*SettingsFrame); !ok { + return ConnectionError(ErrCodeProtocol) + } + sc.sawFirstSettings = true + } + + switch f := f.(type) { + case *SettingsFrame: + return sc.processSettings(f) + case *MetaHeadersFrame: + return sc.processHeaders(f) + case *WindowUpdateFrame: + return sc.processWindowUpdate(f) + case *PingFrame: + return sc.processPing(f) + case *DataFrame: + return sc.processData(f) + case *RSTStreamFrame: + return sc.processResetStream(f) + case *PriorityFrame: + return sc.processPriority(f) + case *GoAwayFrame: + return sc.processGoAway(f) + case *PushPromiseFrame: + // A client cannot push. Thus, servers MUST treat the receipt of a PUSH_PROMISE + // frame as a connection error (Section 5.4.1) of type PROTOCOL_ERROR. + return ConnectionError(ErrCodeProtocol) + default: + sc.vlogf("http2: server ignoring frame: %v", f.Header()) + return nil + } +} + +func (sc *serverConn) processPing(f *PingFrame) error { + sc.serveG.check() + if f.IsAck() { + // 6.7 PING: " An endpoint MUST NOT respond to PING frames + // containing this flag." + return nil + } + if f.StreamID != 0 { + // "PING frames are not associated with any individual + // stream. If a PING frame is received with a stream + // identifier field value other than 0x0, the recipient MUST + // respond with a connection error (Section 5.4.1) of type + // PROTOCOL_ERROR." + return ConnectionError(ErrCodeProtocol) + } + if sc.inGoAway && sc.goAwayCode != ErrCodeNo { + return nil + } + sc.writeFrame(FrameWriteRequest{write: writePingAck{f}}) + return nil +} + +func (sc *serverConn) processWindowUpdate(f *WindowUpdateFrame) error { + sc.serveG.check() + switch { + case f.StreamID != 0: // stream-level flow control + state, st := sc.state(f.StreamID) + if state == stateIdle { + // Section 5.1: "Receiving any frame other than HEADERS + // or PRIORITY on a stream in this state MUST be + // treated as a connection error (Section 5.4.1) of + // type PROTOCOL_ERROR." + return ConnectionError(ErrCodeProtocol) + } + if st == nil { + // "WINDOW_UPDATE can be sent by a peer that has sent a + // frame bearing the END_STREAM flag. This means that a + // receiver could receive a WINDOW_UPDATE frame on a "half + // closed (remote)" or "closed" stream. A receiver MUST + // NOT treat this as an error, see Section 5.1." + return nil + } + if !st.flow.add(int32(f.Increment)) { + return streamError(f.StreamID, ErrCodeFlowControl) + } + default: // connection-level flow control + if !sc.flow.add(int32(f.Increment)) { + return goAwayFlowError{} + } + } + sc.scheduleFrameWrite() + return nil +} + +func (sc *serverConn) processResetStream(f *RSTStreamFrame) error { + sc.serveG.check() + + state, st := sc.state(f.StreamID) + if state == stateIdle { + // 6.4 "RST_STREAM frames MUST NOT be sent for a + // stream in the "idle" state. If a RST_STREAM frame + // identifying an idle stream is received, the + // recipient MUST treat this as a connection error + // (Section 5.4.1) of type PROTOCOL_ERROR. + return ConnectionError(ErrCodeProtocol) + } + if st != nil { + st.cancelCtx() + sc.closeStream(st, streamError(f.StreamID, f.ErrCode)) + } + return nil +} + +func (sc *serverConn) closeStream(st *stream, err error) { + sc.serveG.check() + if st.state == stateIdle || st.state == stateClosed { + panic(fmt.Sprintf("invariant; can't close stream in state %v", st.state)) + } + st.state = stateClosed + if st.writeDeadline != nil { + st.writeDeadline.Stop() + } + if st.isPushed() { + sc.curPushedStreams-- + } else { + sc.curClientStreams-- + } + delete(sc.streams, st.id) + if len(sc.streams) == 0 { + sc.setConnState(http.StateIdle) + if sc.srv.IdleTimeout != 0 { + sc.idleTimer.Reset(sc.srv.IdleTimeout) + } + if h1ServerKeepAlivesDisabled(sc.hs) { + sc.startGracefulShutdownInternal() + } + } + if p := st.body; p != nil { + // Return any buffered unread bytes worth of conn-level flow control. + // See golang.org/issue/16481 + sc.sendWindowUpdate(nil, p.Len()) + + p.CloseWithError(err) + } + st.cw.Close() // signals Handler's CloseNotifier, unblocks writes, etc + sc.writeSched.CloseStream(st.id) +} + +func (sc *serverConn) processSettings(f *SettingsFrame) error { + sc.serveG.check() + if f.IsAck() { + sc.unackedSettings-- + if sc.unackedSettings < 0 { + // Why is the peer ACKing settings we never sent? + // The spec doesn't mention this case, but + // hang up on them anyway. + return ConnectionError(ErrCodeProtocol) + } + return nil + } + if f.NumSettings() > 100 || f.HasDuplicates() { + // This isn't actually in the spec, but hang up on + // suspiciously large settings frames or those with + // duplicate entries. + return ConnectionError(ErrCodeProtocol) + } + if err := f.ForeachSetting(sc.processSetting); err != nil { + return err + } + // TODO: judging by RFC 7540, Section 6.5.3 each SETTINGS frame should be + // acknowledged individually, even if multiple are received before the ACK. + sc.needToSendSettingsAck = true + sc.scheduleFrameWrite() + return nil +} + +func (sc *serverConn) processSetting(s Setting) error { + sc.serveG.check() + if err := s.Valid(); err != nil { + return err + } + if VerboseLogs { + sc.vlogf("http2: server processing setting %v", s) + } + switch s.ID { + case SettingHeaderTableSize: + sc.headerTableSize = s.Val + sc.hpackEncoder.SetMaxDynamicTableSize(s.Val) + case SettingEnablePush: + sc.pushEnabled = s.Val != 0 + case SettingMaxConcurrentStreams: + sc.clientMaxStreams = s.Val + case SettingInitialWindowSize: + return sc.processSettingInitialWindowSize(s.Val) + case SettingMaxFrameSize: + sc.maxFrameSize = int32(s.Val) // the maximum valid s.Val is < 2^31 + case SettingMaxHeaderListSize: + sc.peerMaxHeaderListSize = s.Val + default: + // Unknown setting: "An endpoint that receives a SETTINGS + // frame with any unknown or unsupported identifier MUST + // ignore that setting." + if VerboseLogs { + sc.vlogf("http2: server ignoring unknown setting %v", s) + } + } + return nil +} + +func (sc *serverConn) processSettingInitialWindowSize(val uint32) error { + sc.serveG.check() + // Note: val already validated to be within range by + // processSetting's Valid call. + + // "A SETTINGS frame can alter the initial flow control window + // size for all current streams. When the value of + // SETTINGS_INITIAL_WINDOW_SIZE changes, a receiver MUST + // adjust the size of all stream flow control windows that it + // maintains by the difference between the new value and the + // old value." + old := sc.initialStreamSendWindowSize + sc.initialStreamSendWindowSize = int32(val) + growth := int32(val) - old // may be negative + for _, st := range sc.streams { + if !st.flow.add(growth) { + // 6.9.2 Initial Flow Control Window Size + // "An endpoint MUST treat a change to + // SETTINGS_INITIAL_WINDOW_SIZE that causes any flow + // control window to exceed the maximum size as a + // connection error (Section 5.4.1) of type + // FLOW_CONTROL_ERROR." + return ConnectionError(ErrCodeFlowControl) + } + } + return nil +} + +func (sc *serverConn) processData(f *DataFrame) error { + sc.serveG.check() + if sc.inGoAway && sc.goAwayCode != ErrCodeNo { + return nil + } + data := f.Data() + + // "If a DATA frame is received whose stream is not in "open" + // or "half closed (local)" state, the recipient MUST respond + // with a stream error (Section 5.4.2) of type STREAM_CLOSED." + id := f.Header().StreamID + state, st := sc.state(id) + if id == 0 || state == stateIdle { + // Section 5.1: "Receiving any frame other than HEADERS + // or PRIORITY on a stream in this state MUST be + // treated as a connection error (Section 5.4.1) of + // type PROTOCOL_ERROR." + return ConnectionError(ErrCodeProtocol) + } + if st == nil || state != stateOpen || st.gotTrailerHeader || st.resetQueued { + // This includes sending a RST_STREAM if the stream is + // in stateHalfClosedLocal (which currently means that + // the http.Handler returned, so it's done reading & + // done writing). Try to stop the client from sending + // more DATA. + + // But still enforce their connection-level flow control, + // and return any flow control bytes since we're not going + // to consume them. + if sc.inflow.available() < int32(f.Length) { + return streamError(id, ErrCodeFlowControl) + } + // Deduct the flow control from inflow, since we're + // going to immediately add it back in + // sendWindowUpdate, which also schedules sending the + // frames. + sc.inflow.take(int32(f.Length)) + sc.sendWindowUpdate(nil, int(f.Length)) // conn-level + + if st != nil && st.resetQueued { + // Already have a stream error in flight. Don't send another. + return nil + } + return streamError(id, ErrCodeStreamClosed) + } + if st.body == nil { + panic("internal error: should have a body in this state") + } + + // Sender sending more than they'd declared? + if st.declBodyBytes != -1 && st.bodyBytes+int64(len(data)) > st.declBodyBytes { + st.body.CloseWithError(fmt.Errorf("sender tried to send more than declared Content-Length of %d bytes", st.declBodyBytes)) + // RFC 7540, sec 8.1.2.6: A request or response is also malformed if the + // value of a content-length header field does not equal the sum of the + // DATA frame payload lengths that form the body. + return streamError(id, ErrCodeProtocol) + } + if f.Length > 0 { + // Check whether the client has flow control quota. + if st.inflow.available() < int32(f.Length) { + return streamError(id, ErrCodeFlowControl) + } + st.inflow.take(int32(f.Length)) + + if len(data) > 0 { + wrote, err := st.body.Write(data) + if err != nil { + return streamError(id, ErrCodeStreamClosed) + } + if wrote != len(data) { + panic("internal error: bad Writer") + } + st.bodyBytes += int64(len(data)) + } + + // Return any padded flow control now, since we won't + // refund it later on body reads. + if pad := int32(f.Length) - int32(len(data)); pad > 0 { + sc.sendWindowUpdate32(nil, pad) + sc.sendWindowUpdate32(st, pad) + } + } + if f.StreamEnded() { + st.endStream() + } + return nil +} + +func (sc *serverConn) processGoAway(f *GoAwayFrame) error { + sc.serveG.check() + if f.ErrCode != ErrCodeNo { + sc.logf("http2: received GOAWAY %+v, starting graceful shutdown", f) + } else { + sc.vlogf("http2: received GOAWAY %+v, starting graceful shutdown", f) + } + sc.startGracefulShutdownInternal() + // http://tools.ietf.org/html/rfc7540#section-6.8 + // We should not create any new streams, which means we should disable push. + sc.pushEnabled = false + return nil +} + +// isPushed reports whether the stream is server-initiated. +func (st *stream) isPushed() bool { + return st.id%2 == 0 +} + +// endStream closes a Request.Body's pipe. It is called when a DATA +// frame says a request body is over (or after trailers). +func (st *stream) endStream() { + sc := st.sc + sc.serveG.check() + + if st.declBodyBytes != -1 && st.declBodyBytes != st.bodyBytes { + st.body.CloseWithError(fmt.Errorf("request declared a Content-Length of %d but only wrote %d bytes", + st.declBodyBytes, st.bodyBytes)) + } else { + st.body.closeWithErrorAndCode(io.EOF, st.copyTrailersToHandlerRequest) + st.body.CloseWithError(io.EOF) + } + st.state = stateHalfClosedRemote +} + +// copyTrailersToHandlerRequest is run in the Handler's goroutine in +// its Request.Body.Read just before it gets io.EOF. +func (st *stream) copyTrailersToHandlerRequest() { + for k, vv := range st.trailer { + if _, ok := st.reqTrailer[k]; ok { + // Only copy it over it was pre-declared. + st.reqTrailer[k] = vv + } + } +} + +// onWriteTimeout is run on its own goroutine (from time.AfterFunc) +// when the stream's WriteTimeout has fired. +func (st *stream) onWriteTimeout() { + st.sc.writeFrameFromHandler(FrameWriteRequest{write: streamError(st.id, ErrCodeInternal)}) +} + +func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error { + sc.serveG.check() + id := f.StreamID + if sc.inGoAway { + // Ignore. + return nil + } + // http://tools.ietf.org/html/rfc7540#section-5.1.1 + // Streams initiated by a client MUST use odd-numbered stream + // identifiers. [...] An endpoint that receives an unexpected + // stream identifier MUST respond with a connection error + // (Section 5.4.1) of type PROTOCOL_ERROR. + if id%2 != 1 { + return ConnectionError(ErrCodeProtocol) + } + // A HEADERS frame can be used to create a new stream or + // send a trailer for an open one. If we already have a stream + // open, let it process its own HEADERS frame (trailers at this + // point, if it's valid). + if st := sc.streams[f.StreamID]; st != nil { + if st.resetQueued { + // We're sending RST_STREAM to close the stream, so don't bother + // processing this frame. + return nil + } + // RFC 7540, sec 5.1: If an endpoint receives additional frames, other than + // WINDOW_UPDATE, PRIORITY, or RST_STREAM, for a stream that is in + // this state, it MUST respond with a stream error (Section 5.4.2) of + // type STREAM_CLOSED. + if st.state == stateHalfClosedRemote { + return streamError(id, ErrCodeStreamClosed) + } + return st.processTrailerHeaders(f) + } + + // [...] The identifier of a newly established stream MUST be + // numerically greater than all streams that the initiating + // endpoint has opened or reserved. [...] An endpoint that + // receives an unexpected stream identifier MUST respond with + // a connection error (Section 5.4.1) of type PROTOCOL_ERROR. + if id <= sc.maxClientStreamID { + return ConnectionError(ErrCodeProtocol) + } + sc.maxClientStreamID = id + + if sc.idleTimer != nil { + sc.idleTimer.Stop() + } + + // http://tools.ietf.org/html/rfc7540#section-5.1.2 + // [...] Endpoints MUST NOT exceed the limit set by their peer. An + // endpoint that receives a HEADERS frame that causes their + // advertised concurrent stream limit to be exceeded MUST treat + // this as a stream error (Section 5.4.2) of type PROTOCOL_ERROR + // or REFUSED_STREAM. + if sc.curClientStreams+1 > sc.advMaxStreams { + if sc.unackedSettings == 0 { + // They should know better. + return streamError(id, ErrCodeProtocol) + } + // Assume it's a network race, where they just haven't + // received our last SETTINGS update. But actually + // this can't happen yet, because we don't yet provide + // a way for users to adjust server parameters at + // runtime. + return streamError(id, ErrCodeRefusedStream) + } + + initialState := stateOpen + if f.StreamEnded() { + initialState = stateHalfClosedRemote + } + st := sc.newStream(id, 0, initialState) + + if f.HasPriority() { + if err := checkPriority(f.StreamID, f.Priority); err != nil { + return err + } + sc.writeSched.AdjustStream(st.id, f.Priority) + } + + rw, req, err := sc.newWriterAndRequest(st, f) + if err != nil { + return err + } + st.reqTrailer = req.Trailer + if st.reqTrailer != nil { + st.trailer = make(http.Header) + } + st.body = req.Body.(*requestBody).pipe // may be nil + st.declBodyBytes = req.ContentLength + + handler := sc.handler.ServeHTTP + if f.Truncated { + // Their header list was too long. Send a 431 error. + handler = handleHeaderListTooLong + } else if err := checkValidHTTP2RequestHeaders(req.Header); err != nil { + handler = new400Handler(err) + } + + // The net/http package sets the read deadline from the + // http.Server.ReadTimeout during the TLS handshake, but then + // passes the connection off to us with the deadline already + // set. Disarm it here after the request headers are read, + // similar to how the http1 server works. Here it's + // technically more like the http1 Server's ReadHeaderTimeout + // (in Go 1.8), though. That's a more sane option anyway. + if sc.hs.ReadTimeout != 0 { + sc.conn.SetReadDeadline(time.Time{}) + } + + go sc.runHandler(rw, req, handler) + return nil +} + +func (st *stream) processTrailerHeaders(f *MetaHeadersFrame) error { + sc := st.sc + sc.serveG.check() + if st.gotTrailerHeader { + return ConnectionError(ErrCodeProtocol) + } + st.gotTrailerHeader = true + if !f.StreamEnded() { + return streamError(st.id, ErrCodeProtocol) + } + + if len(f.PseudoFields()) > 0 { + return streamError(st.id, ErrCodeProtocol) + } + if st.trailer != nil { + for _, hf := range f.RegularFields() { + key := sc.canonicalHeader(hf.Name) + if !httpguts.ValidTrailerHeader(key) { + // TODO: send more details to the peer somehow. But http2 has + // no way to send debug data at a stream level. Discuss with + // HTTP folk. + return streamError(st.id, ErrCodeProtocol) + } + st.trailer[key] = append(st.trailer[key], hf.Value) + } + } + st.endStream() + return nil +} + +func checkPriority(streamID uint32, p PriorityParam) error { + if streamID == p.StreamDep { + // Section 5.3.1: "A stream cannot depend on itself. An endpoint MUST treat + // this as a stream error (Section 5.4.2) of type PROTOCOL_ERROR." + // Section 5.3.3 says that a stream can depend on one of its dependencies, + // so it's only self-dependencies that are forbidden. + return streamError(streamID, ErrCodeProtocol) + } + return nil +} + +func (sc *serverConn) processPriority(f *PriorityFrame) error { + if sc.inGoAway { + return nil + } + if err := checkPriority(f.StreamID, f.PriorityParam); err != nil { + return err + } + sc.writeSched.AdjustStream(f.StreamID, f.PriorityParam) + return nil +} + +func (sc *serverConn) newStream(id, pusherID uint32, state streamState) *stream { + sc.serveG.check() + if id == 0 { + panic("internal error: cannot create stream with id 0") + } + + ctx, cancelCtx := context.WithCancel(sc.baseCtx) + st := &stream{ + sc: sc, + id: id, + state: state, + ctx: ctx, + cancelCtx: cancelCtx, + } + st.cw.Init() + st.flow.conn = &sc.flow // link to conn-level counter + st.flow.add(sc.initialStreamSendWindowSize) + st.inflow.conn = &sc.inflow // link to conn-level counter + st.inflow.add(sc.srv.initialStreamRecvWindowSize()) + if sc.hs.WriteTimeout != 0 { + st.writeDeadline = time.AfterFunc(sc.hs.WriteTimeout, st.onWriteTimeout) + } + + sc.streams[id] = st + sc.writeSched.OpenStream(st.id, OpenStreamOptions{PusherID: pusherID}) + if st.isPushed() { + sc.curPushedStreams++ + } else { + sc.curClientStreams++ + } + if sc.curOpenStreams() == 1 { + sc.setConnState(http.StateActive) + } + + return st +} + +func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*responseWriter, *http.Request, error) { + sc.serveG.check() + + rp := requestParam{ + method: f.PseudoValue("method"), + scheme: f.PseudoValue("scheme"), + authority: f.PseudoValue("authority"), + path: f.PseudoValue("path"), + } + + isConnect := rp.method == "CONNECT" + if isConnect { + if rp.path != "" || rp.scheme != "" || rp.authority == "" { + return nil, nil, streamError(f.StreamID, ErrCodeProtocol) + } + } else if rp.method == "" || rp.path == "" || (rp.scheme != "https" && rp.scheme != "http") { + // See 8.1.2.6 Malformed Requests and Responses: + // + // Malformed requests or responses that are detected + // MUST be treated as a stream error (Section 5.4.2) + // of type PROTOCOL_ERROR." + // + // 8.1.2.3 Request Pseudo-Header Fields + // "All HTTP/2 requests MUST include exactly one valid + // value for the :method, :scheme, and :path + // pseudo-header fields" + return nil, nil, streamError(f.StreamID, ErrCodeProtocol) + } + + bodyOpen := !f.StreamEnded() + if rp.method == "HEAD" && bodyOpen { + // HEAD requests can't have bodies + return nil, nil, streamError(f.StreamID, ErrCodeProtocol) + } + + rp.header = make(http.Header) + for _, hf := range f.RegularFields() { + rp.header.Add(sc.canonicalHeader(hf.Name), hf.Value) + } + if rp.authority == "" { + rp.authority = rp.header.Get("Host") + } + + rw, req, err := sc.newWriterAndRequestNoBody(st, rp) + if err != nil { + return nil, nil, err + } + if bodyOpen { + if vv, ok := rp.header["Content-Length"]; ok { + req.ContentLength, _ = strconv.ParseInt(vv[0], 10, 64) + } else { + req.ContentLength = -1 + } + req.Body.(*requestBody).pipe = &pipe{ + b: &dataBuffer{expected: req.ContentLength}, + } + } + return rw, req, nil +} + +type requestParam struct { + method string + scheme, authority, path string + header http.Header +} + +func (sc *serverConn) newWriterAndRequestNoBody(st *stream, rp requestParam) (*responseWriter, *http.Request, error) { + sc.serveG.check() + + var tlsState *tls.ConnectionState // nil if not scheme https + if rp.scheme == "https" { + tlsState = sc.tlsState + } + + needsContinue := rp.header.Get("Expect") == "100-continue" + if needsContinue { + rp.header.Del("Expect") + } + // Merge Cookie headers into one "; "-delimited value. + if cookies := rp.header["Cookie"]; len(cookies) > 1 { + rp.header.Set("Cookie", strings.Join(cookies, "; ")) + } + + // Setup Trailers + var trailer http.Header + for _, v := range rp.header["Trailer"] { + for _, key := range strings.Split(v, ",") { + key = http.CanonicalHeaderKey(strings.TrimSpace(key)) + switch key { + case "Transfer-Encoding", "Trailer", "Content-Length": + // Bogus. (copy of http1 rules) + // Ignore. + default: + if trailer == nil { + trailer = make(http.Header) + } + trailer[key] = nil + } + } + } + delete(rp.header, "Trailer") + + var url_ *url.URL + var requestURI string + if rp.method == "CONNECT" { + url_ = &url.URL{Host: rp.authority} + requestURI = rp.authority // mimic HTTP/1 server behavior + } else { + var err error + url_, err = url.ParseRequestURI(rp.path) + if err != nil { + return nil, nil, streamError(st.id, ErrCodeProtocol) + } + requestURI = rp.path + } + + body := &requestBody{ + conn: sc, + stream: st, + needsContinue: needsContinue, + } + req := &http.Request{ + Method: rp.method, + URL: url_, + RemoteAddr: sc.remoteAddrStr, + Header: rp.header, + RequestURI: requestURI, + Proto: "HTTP/2.0", + ProtoMajor: 2, + ProtoMinor: 0, + TLS: tlsState, + Host: rp.authority, + Body: body, + Trailer: trailer, + } + req = req.WithContext(st.ctx) + + rws := responseWriterStatePool.Get().(*responseWriterState) + bwSave := rws.bw + *rws = responseWriterState{} // zero all the fields + rws.conn = sc + rws.bw = bwSave + rws.bw.Reset(chunkWriter{rws}) + rws.stream = st + rws.req = req + rws.body = body + + rw := &responseWriter{rws: rws} + return rw, req, nil +} + +// Run on its own goroutine. +func (sc *serverConn) runHandler(rw *responseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) { + didPanic := true + defer func() { + rw.rws.stream.cancelCtx() + if didPanic { + e := recover() + sc.writeFrameFromHandler(FrameWriteRequest{ + write: handlerPanicRST{rw.rws.stream.id}, + stream: rw.rws.stream, + }) + // Same as net/http: + if e != nil && e != http.ErrAbortHandler { + const size = 64 << 10 + buf := make([]byte, size) + buf = buf[:runtime.Stack(buf, false)] + sc.logf("http2: panic serving %v: %v\n%s", sc.conn.RemoteAddr(), e, buf) + } + return + } + rw.handlerDone() + }() + handler(rw, req) + didPanic = false +} + +func handleHeaderListTooLong(w http.ResponseWriter, r *http.Request) { + // 10.5.1 Limits on Header Block Size: + // .. "A server that receives a larger header block than it is + // willing to handle can send an HTTP 431 (Request Header Fields Too + // Large) status code" + const statusRequestHeaderFieldsTooLarge = 431 // only in Go 1.6+ + w.WriteHeader(statusRequestHeaderFieldsTooLarge) + io.WriteString(w, "<h1>HTTP Error 431</h1><p>Request Header Field(s) Too Large</p>") +} + +// called from handler goroutines. +// h may be nil. +func (sc *serverConn) writeHeaders(st *stream, headerData *writeResHeaders) error { + sc.serveG.checkNotOn() // NOT on + var errc chan error + if headerData.h != nil { + // If there's a header map (which we don't own), so we have to block on + // waiting for this frame to be written, so an http.Flush mid-handler + // writes out the correct value of keys, before a handler later potentially + // mutates it. + errc = errChanPool.Get().(chan error) + } + if err := sc.writeFrameFromHandler(FrameWriteRequest{ + write: headerData, + stream: st, + done: errc, + }); err != nil { + return err + } + if errc != nil { + select { + case err := <-errc: + errChanPool.Put(errc) + return err + case <-sc.doneServing: + return errClientDisconnected + case <-st.cw: + return errStreamClosed + } + } + return nil +} + +// called from handler goroutines. +func (sc *serverConn) write100ContinueHeaders(st *stream) { + sc.writeFrameFromHandler(FrameWriteRequest{ + write: write100ContinueHeadersFrame{st.id}, + stream: st, + }) +} + +// A bodyReadMsg tells the server loop that the http.Handler read n +// bytes of the DATA from the client on the given stream. +type bodyReadMsg struct { + st *stream + n int +} + +// called from handler goroutines. +// Notes that the handler for the given stream ID read n bytes of its body +// and schedules flow control tokens to be sent. +func (sc *serverConn) noteBodyReadFromHandler(st *stream, n int, err error) { + sc.serveG.checkNotOn() // NOT on + if n > 0 { + select { + case sc.bodyReadCh <- bodyReadMsg{st, n}: + case <-sc.doneServing: + } + } +} + +func (sc *serverConn) noteBodyRead(st *stream, n int) { + sc.serveG.check() + sc.sendWindowUpdate(nil, n) // conn-level + if st.state != stateHalfClosedRemote && st.state != stateClosed { + // Don't send this WINDOW_UPDATE if the stream is closed + // remotely. + sc.sendWindowUpdate(st, n) + } +} + +// st may be nil for conn-level +func (sc *serverConn) sendWindowUpdate(st *stream, n int) { + sc.serveG.check() + // "The legal range for the increment to the flow control + // window is 1 to 2^31-1 (2,147,483,647) octets." + // A Go Read call on 64-bit machines could in theory read + // a larger Read than this. Very unlikely, but we handle it here + // rather than elsewhere for now. + const maxUint31 = 1<<31 - 1 + for n >= maxUint31 { + sc.sendWindowUpdate32(st, maxUint31) + n -= maxUint31 + } + sc.sendWindowUpdate32(st, int32(n)) +} + +// st may be nil for conn-level +func (sc *serverConn) sendWindowUpdate32(st *stream, n int32) { + sc.serveG.check() + if n == 0 { + return + } + if n < 0 { + panic("negative update") + } + var streamID uint32 + if st != nil { + streamID = st.id + } + sc.writeFrame(FrameWriteRequest{ + write: writeWindowUpdate{streamID: streamID, n: uint32(n)}, + stream: st, + }) + var ok bool + if st == nil { + ok = sc.inflow.add(n) + } else { + ok = st.inflow.add(n) + } + if !ok { + panic("internal error; sent too many window updates without decrements?") + } +} + +// requestBody is the Handler's Request.Body type. +// Read and Close may be called concurrently. +type requestBody struct { + stream *stream + conn *serverConn + closed bool // for use by Close only + sawEOF bool // for use by Read only + pipe *pipe // non-nil if we have a HTTP entity message body + needsContinue bool // need to send a 100-continue +} + +func (b *requestBody) Close() error { + if b.pipe != nil && !b.closed { + b.pipe.BreakWithError(errClosedBody) + } + b.closed = true + return nil +} + +func (b *requestBody) Read(p []byte) (n int, err error) { + if b.needsContinue { + b.needsContinue = false + b.conn.write100ContinueHeaders(b.stream) + } + if b.pipe == nil || b.sawEOF { + return 0, io.EOF + } + n, err = b.pipe.Read(p) + if err == io.EOF { + b.sawEOF = true + } + if b.conn == nil && inTests { + return + } + b.conn.noteBodyReadFromHandler(b.stream, n, err) + return +} + +// responseWriter is the http.ResponseWriter implementation. It's +// intentionally small (1 pointer wide) to minimize garbage. The +// responseWriterState pointer inside is zeroed at the end of a +// request (in handlerDone) and calls on the responseWriter thereafter +// simply crash (caller's mistake), but the much larger responseWriterState +// and buffers are reused between multiple requests. +type responseWriter struct { + rws *responseWriterState +} + +// Optional http.ResponseWriter interfaces implemented. +var ( + _ http.CloseNotifier = (*responseWriter)(nil) + _ http.Flusher = (*responseWriter)(nil) + _ stringWriter = (*responseWriter)(nil) +) + +type responseWriterState struct { + // immutable within a request: + stream *stream + req *http.Request + body *requestBody // to close at end of request, if DATA frames didn't + conn *serverConn + + // TODO: adjust buffer writing sizes based on server config, frame size updates from peer, etc + bw *bufio.Writer // writing to a chunkWriter{this *responseWriterState} + + // mutated by http.Handler goroutine: + handlerHeader http.Header // nil until called + snapHeader http.Header // snapshot of handlerHeader at WriteHeader time + trailers []string // set in writeChunk + status int // status code passed to WriteHeader + wroteHeader bool // WriteHeader called (explicitly or implicitly). Not necessarily sent to user yet. + sentHeader bool // have we sent the header frame? + handlerDone bool // handler has finished + dirty bool // a Write failed; don't reuse this responseWriterState + + sentContentLen int64 // non-zero if handler set a Content-Length header + wroteBytes int64 + + closeNotifierMu sync.Mutex // guards closeNotifierCh + closeNotifierCh chan bool // nil until first used +} + +type chunkWriter struct{ rws *responseWriterState } + +func (cw chunkWriter) Write(p []byte) (n int, err error) { return cw.rws.writeChunk(p) } + +func (rws *responseWriterState) hasTrailers() bool { return len(rws.trailers) > 0 } + +func (rws *responseWriterState) hasNonemptyTrailers() bool { + for _, trailer := range rws.trailers { + if _, ok := rws.handlerHeader[trailer]; ok { + return true + } + } + return false +} + +// declareTrailer is called for each Trailer header when the +// response header is written. It notes that a header will need to be +// written in the trailers at the end of the response. +func (rws *responseWriterState) declareTrailer(k string) { + k = http.CanonicalHeaderKey(k) + if !httpguts.ValidTrailerHeader(k) { + // Forbidden by RFC 7230, section 4.1.2. + rws.conn.logf("ignoring invalid trailer %q", k) + return + } + if !strSliceContains(rws.trailers, k) { + rws.trailers = append(rws.trailers, k) + } +} + +// writeChunk writes chunks from the bufio.Writer. But because +// bufio.Writer may bypass its chunking, sometimes p may be +// arbitrarily large. +// +// writeChunk is also responsible (on the first chunk) for sending the +// HEADER response. +func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) { + if !rws.wroteHeader { + rws.writeHeader(200) + } + + isHeadResp := rws.req.Method == "HEAD" + if !rws.sentHeader { + rws.sentHeader = true + var ctype, clen string + if clen = rws.snapHeader.Get("Content-Length"); clen != "" { + rws.snapHeader.Del("Content-Length") + clen64, err := strconv.ParseInt(clen, 10, 64) + if err == nil && clen64 >= 0 { + rws.sentContentLen = clen64 + } else { + clen = "" + } + } + if clen == "" && rws.handlerDone && bodyAllowedForStatus(rws.status) && (len(p) > 0 || !isHeadResp) { + clen = strconv.Itoa(len(p)) + } + _, hasContentType := rws.snapHeader["Content-Type"] + // If the Content-Encoding is non-blank, we shouldn't + // sniff the body. See Issue golang.org/issue/31753. + ce := rws.snapHeader.Get("Content-Encoding") + hasCE := len(ce) > 0 + if !hasCE && !hasContentType && bodyAllowedForStatus(rws.status) && len(p) > 0 { + ctype = http.DetectContentType(p) + } + var date string + if _, ok := rws.snapHeader["Date"]; !ok { + // TODO(bradfitz): be faster here, like net/http? measure. + date = time.Now().UTC().Format(http.TimeFormat) + } + + for _, v := range rws.snapHeader["Trailer"] { + foreachHeaderElement(v, rws.declareTrailer) + } + + // "Connection" headers aren't allowed in HTTP/2 (RFC 7540, 8.1.2.2), + // but respect "Connection" == "close" to mean sending a GOAWAY and tearing + // down the TCP connection when idle, like we do for HTTP/1. + // TODO: remove more Connection-specific header fields here, in addition + // to "Connection". + if _, ok := rws.snapHeader["Connection"]; ok { + v := rws.snapHeader.Get("Connection") + delete(rws.snapHeader, "Connection") + if v == "close" { + rws.conn.startGracefulShutdown() + } + } + + endStream := (rws.handlerDone && !rws.hasTrailers() && len(p) == 0) || isHeadResp + err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{ + streamID: rws.stream.id, + httpResCode: rws.status, + h: rws.snapHeader, + endStream: endStream, + contentType: ctype, + contentLength: clen, + date: date, + }) + if err != nil { + rws.dirty = true + return 0, err + } + if endStream { + return 0, nil + } + } + if isHeadResp { + return len(p), nil + } + if len(p) == 0 && !rws.handlerDone { + return 0, nil + } + + if rws.handlerDone { + rws.promoteUndeclaredTrailers() + } + + // only send trailers if they have actually been defined by the + // server handler. + hasNonemptyTrailers := rws.hasNonemptyTrailers() + endStream := rws.handlerDone && !hasNonemptyTrailers + if len(p) > 0 || endStream { + // only send a 0 byte DATA frame if we're ending the stream. + if err := rws.conn.writeDataFromHandler(rws.stream, p, endStream); err != nil { + rws.dirty = true + return 0, err + } + } + + if rws.handlerDone && hasNonemptyTrailers { + err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{ + streamID: rws.stream.id, + h: rws.handlerHeader, + trailers: rws.trailers, + endStream: true, + }) + if err != nil { + rws.dirty = true + } + return len(p), err + } + return len(p), nil +} + +// TrailerPrefix is a magic prefix for ResponseWriter.Header map keys +// that, if present, signals that the map entry is actually for +// the response trailers, and not the response headers. The prefix +// is stripped after the ServeHTTP call finishes and the values are +// sent in the trailers. +// +// This mechanism is intended only for trailers that are not known +// prior to the headers being written. If the set of trailers is fixed +// or known before the header is written, the normal Go trailers mechanism +// is preferred: +// https://golang.org/pkg/net/http/#ResponseWriter +// https://golang.org/pkg/net/http/#example_ResponseWriter_trailers +const TrailerPrefix = "Trailer:" + +// promoteUndeclaredTrailers permits http.Handlers to set trailers +// after the header has already been flushed. Because the Go +// ResponseWriter interface has no way to set Trailers (only the +// Header), and because we didn't want to expand the ResponseWriter +// interface, and because nobody used trailers, and because RFC 7230 +// says you SHOULD (but not must) predeclare any trailers in the +// header, the official ResponseWriter rules said trailers in Go must +// be predeclared, and then we reuse the same ResponseWriter.Header() +// map to mean both Headers and Trailers. When it's time to write the +// Trailers, we pick out the fields of Headers that were declared as +// trailers. That worked for a while, until we found the first major +// user of Trailers in the wild: gRPC (using them only over http2), +// and gRPC libraries permit setting trailers mid-stream without +// predeclaring them. So: change of plans. We still permit the old +// way, but we also permit this hack: if a Header() key begins with +// "Trailer:", the suffix of that key is a Trailer. Because ':' is an +// invalid token byte anyway, there is no ambiguity. (And it's already +// filtered out) It's mildly hacky, but not terrible. +// +// This method runs after the Handler is done and promotes any Header +// fields to be trailers. +func (rws *responseWriterState) promoteUndeclaredTrailers() { + for k, vv := range rws.handlerHeader { + if !strings.HasPrefix(k, TrailerPrefix) { + continue + } + trailerKey := strings.TrimPrefix(k, TrailerPrefix) + rws.declareTrailer(trailerKey) + rws.handlerHeader[http.CanonicalHeaderKey(trailerKey)] = vv + } + + if len(rws.trailers) > 1 { + sorter := sorterPool.Get().(*sorter) + sorter.SortStrings(rws.trailers) + sorterPool.Put(sorter) + } +} + +func (w *responseWriter) Flush() { + rws := w.rws + if rws == nil { + panic("Header called after Handler finished") + } + if rws.bw.Buffered() > 0 { + if err := rws.bw.Flush(); err != nil { + // Ignore the error. The frame writer already knows. + return + } + } else { + // The bufio.Writer won't call chunkWriter.Write + // (writeChunk with zero bytes, so we have to do it + // ourselves to force the HTTP response header and/or + // final DATA frame (with END_STREAM) to be sent. + rws.writeChunk(nil) + } +} + +func (w *responseWriter) CloseNotify() <-chan bool { + rws := w.rws + if rws == nil { + panic("CloseNotify called after Handler finished") + } + rws.closeNotifierMu.Lock() + ch := rws.closeNotifierCh + if ch == nil { + ch = make(chan bool, 1) + rws.closeNotifierCh = ch + cw := rws.stream.cw + go func() { + cw.Wait() // wait for close + ch <- true + }() + } + rws.closeNotifierMu.Unlock() + return ch +} + +func (w *responseWriter) Header() http.Header { + rws := w.rws + if rws == nil { + panic("Header called after Handler finished") + } + if rws.handlerHeader == nil { + rws.handlerHeader = make(http.Header) + } + return rws.handlerHeader +} + +// checkWriteHeaderCode is a copy of net/http's checkWriteHeaderCode. +func checkWriteHeaderCode(code int) { + // Issue 22880: require valid WriteHeader status codes. + // For now we only enforce that it's three digits. + // In the future we might block things over 599 (600 and above aren't defined + // at http://httpwg.org/specs/rfc7231.html#status.codes) + // and we might block under 200 (once we have more mature 1xx support). + // But for now any three digits. + // + // We used to send "HTTP/1.1 000 0" on the wire in responses but there's + // no equivalent bogus thing we can realistically send in HTTP/2, + // so we'll consistently panic instead and help people find their bugs + // early. (We can't return an error from WriteHeader even if we wanted to.) + if code < 100 || code > 999 { + panic(fmt.Sprintf("invalid WriteHeader code %v", code)) + } +} + +func (w *responseWriter) WriteHeader(code int) { + rws := w.rws + if rws == nil { + panic("WriteHeader called after Handler finished") + } + rws.writeHeader(code) +} + +func (rws *responseWriterState) writeHeader(code int) { + if !rws.wroteHeader { + checkWriteHeaderCode(code) + rws.wroteHeader = true + rws.status = code + if len(rws.handlerHeader) > 0 { + rws.snapHeader = cloneHeader(rws.handlerHeader) + } + } +} + +func cloneHeader(h http.Header) http.Header { + h2 := make(http.Header, len(h)) + for k, vv := range h { + vv2 := make([]string, len(vv)) + copy(vv2, vv) + h2[k] = vv2 + } + return h2 +} + +// The Life Of A Write is like this: +// +// * Handler calls w.Write or w.WriteString -> +// * -> rws.bw (*bufio.Writer) -> +// * (Handler might call Flush) +// * -> chunkWriter{rws} +// * -> responseWriterState.writeChunk(p []byte) +// * -> responseWriterState.writeChunk (most of the magic; see comment there) +func (w *responseWriter) Write(p []byte) (n int, err error) { + return w.write(len(p), p, "") +} + +func (w *responseWriter) WriteString(s string) (n int, err error) { + return w.write(len(s), nil, s) +} + +// either dataB or dataS is non-zero. +func (w *responseWriter) write(lenData int, dataB []byte, dataS string) (n int, err error) { + rws := w.rws + if rws == nil { + panic("Write called after Handler finished") + } + if !rws.wroteHeader { + w.WriteHeader(200) + } + if !bodyAllowedForStatus(rws.status) { + return 0, http.ErrBodyNotAllowed + } + rws.wroteBytes += int64(len(dataB)) + int64(len(dataS)) // only one can be set + if rws.sentContentLen != 0 && rws.wroteBytes > rws.sentContentLen { + // TODO: send a RST_STREAM + return 0, errors.New("http2: handler wrote more than declared Content-Length") + } + + if dataB != nil { + return rws.bw.Write(dataB) + } else { + return rws.bw.WriteString(dataS) + } +} + +func (w *responseWriter) handlerDone() { + rws := w.rws + dirty := rws.dirty + rws.handlerDone = true + w.Flush() + w.rws = nil + if !dirty { + // Only recycle the pool if all prior Write calls to + // the serverConn goroutine completed successfully. If + // they returned earlier due to resets from the peer + // there might still be write goroutines outstanding + // from the serverConn referencing the rws memory. See + // issue 20704. + responseWriterStatePool.Put(rws) + } +} + +// Push errors. +var ( + ErrRecursivePush = errors.New("http2: recursive push not allowed") + ErrPushLimitReached = errors.New("http2: push would exceed peer's SETTINGS_MAX_CONCURRENT_STREAMS") +) + +var _ http.Pusher = (*responseWriter)(nil) + +func (w *responseWriter) Push(target string, opts *http.PushOptions) error { + st := w.rws.stream + sc := st.sc + sc.serveG.checkNotOn() + + // No recursive pushes: "PUSH_PROMISE frames MUST only be sent on a peer-initiated stream." + // http://tools.ietf.org/html/rfc7540#section-6.6 + if st.isPushed() { + return ErrRecursivePush + } + + if opts == nil { + opts = new(http.PushOptions) + } + + // Default options. + if opts.Method == "" { + opts.Method = "GET" + } + if opts.Header == nil { + opts.Header = http.Header{} + } + wantScheme := "http" + if w.rws.req.TLS != nil { + wantScheme = "https" + } + + // Validate the request. + u, err := url.Parse(target) + if err != nil { + return err + } + if u.Scheme == "" { + if !strings.HasPrefix(target, "/") { + return fmt.Errorf("target must be an absolute URL or an absolute path: %q", target) + } + u.Scheme = wantScheme + u.Host = w.rws.req.Host + } else { + if u.Scheme != wantScheme { + return fmt.Errorf("cannot push URL with scheme %q from request with scheme %q", u.Scheme, wantScheme) + } + if u.Host == "" { + return errors.New("URL must have a host") + } + } + for k := range opts.Header { + if strings.HasPrefix(k, ":") { + return fmt.Errorf("promised request headers cannot include pseudo header %q", k) + } + // These headers are meaningful only if the request has a body, + // but PUSH_PROMISE requests cannot have a body. + // http://tools.ietf.org/html/rfc7540#section-8.2 + // Also disallow Host, since the promised URL must be absolute. + switch strings.ToLower(k) { + case "content-length", "content-encoding", "trailer", "te", "expect", "host": + return fmt.Errorf("promised request headers cannot include %q", k) + } + } + if err := checkValidHTTP2RequestHeaders(opts.Header); err != nil { + return err + } + + // The RFC effectively limits promised requests to GET and HEAD: + // "Promised requests MUST be cacheable [GET, HEAD, or POST], and MUST be safe [GET or HEAD]" + // http://tools.ietf.org/html/rfc7540#section-8.2 + if opts.Method != "GET" && opts.Method != "HEAD" { + return fmt.Errorf("method %q must be GET or HEAD", opts.Method) + } + + msg := &startPushRequest{ + parent: st, + method: opts.Method, + url: u, + header: cloneHeader(opts.Header), + done: errChanPool.Get().(chan error), + } + + select { + case <-sc.doneServing: + return errClientDisconnected + case <-st.cw: + return errStreamClosed + case sc.serveMsgCh <- msg: + } + + select { + case <-sc.doneServing: + return errClientDisconnected + case <-st.cw: + return errStreamClosed + case err := <-msg.done: + errChanPool.Put(msg.done) + return err + } +} + +type startPushRequest struct { + parent *stream + method string + url *url.URL + header http.Header + done chan error +} + +func (sc *serverConn) startPush(msg *startPushRequest) { + sc.serveG.check() + + // http://tools.ietf.org/html/rfc7540#section-6.6. + // PUSH_PROMISE frames MUST only be sent on a peer-initiated stream that + // is in either the "open" or "half-closed (remote)" state. + if msg.parent.state != stateOpen && msg.parent.state != stateHalfClosedRemote { + // responseWriter.Push checks that the stream is peer-initiated. + msg.done <- errStreamClosed + return + } + + // http://tools.ietf.org/html/rfc7540#section-6.6. + if !sc.pushEnabled { + msg.done <- http.ErrNotSupported + return + } + + // PUSH_PROMISE frames must be sent in increasing order by stream ID, so + // we allocate an ID for the promised stream lazily, when the PUSH_PROMISE + // is written. Once the ID is allocated, we start the request handler. + allocatePromisedID := func() (uint32, error) { + sc.serveG.check() + + // Check this again, just in case. Technically, we might have received + // an updated SETTINGS by the time we got around to writing this frame. + if !sc.pushEnabled { + return 0, http.ErrNotSupported + } + // http://tools.ietf.org/html/rfc7540#section-6.5.2. + if sc.curPushedStreams+1 > sc.clientMaxStreams { + return 0, ErrPushLimitReached + } + + // http://tools.ietf.org/html/rfc7540#section-5.1.1. + // Streams initiated by the server MUST use even-numbered identifiers. + // A server that is unable to establish a new stream identifier can send a GOAWAY + // frame so that the client is forced to open a new connection for new streams. + if sc.maxPushPromiseID+2 >= 1<<31 { + sc.startGracefulShutdownInternal() + return 0, ErrPushLimitReached + } + sc.maxPushPromiseID += 2 + promisedID := sc.maxPushPromiseID + + // http://tools.ietf.org/html/rfc7540#section-8.2. + // Strictly speaking, the new stream should start in "reserved (local)", then + // transition to "half closed (remote)" after sending the initial HEADERS, but + // we start in "half closed (remote)" for simplicity. + // See further comments at the definition of stateHalfClosedRemote. + promised := sc.newStream(promisedID, msg.parent.id, stateHalfClosedRemote) + rw, req, err := sc.newWriterAndRequestNoBody(promised, requestParam{ + method: msg.method, + scheme: msg.url.Scheme, + authority: msg.url.Host, + path: msg.url.RequestURI(), + header: cloneHeader(msg.header), // clone since handler runs concurrently with writing the PUSH_PROMISE + }) + if err != nil { + // Should not happen, since we've already validated msg.url. + panic(fmt.Sprintf("newWriterAndRequestNoBody(%+v): %v", msg.url, err)) + } + + go sc.runHandler(rw, req, sc.handler.ServeHTTP) + return promisedID, nil + } + + sc.writeFrame(FrameWriteRequest{ + write: &writePushPromise{ + streamID: msg.parent.id, + method: msg.method, + url: msg.url, + h: msg.header, + allocatePromisedID: allocatePromisedID, + }, + stream: msg.parent, + done: msg.done, + }) +} + +// foreachHeaderElement splits v according to the "#rule" construction +// in RFC 7230 section 7 and calls fn for each non-empty element. +func foreachHeaderElement(v string, fn func(string)) { + v = textproto.TrimString(v) + if v == "" { + return + } + if !strings.Contains(v, ",") { + fn(v) + return + } + for _, f := range strings.Split(v, ",") { + if f = textproto.TrimString(f); f != "" { + fn(f) + } + } +} + +// From http://httpwg.org/specs/rfc7540.html#rfc.section.8.1.2.2 +var connHeaders = []string{ + "Connection", + "Keep-Alive", + "Proxy-Connection", + "Transfer-Encoding", + "Upgrade", +} + +// checkValidHTTP2RequestHeaders checks whether h is a valid HTTP/2 request, +// per RFC 7540 Section 8.1.2.2. +// The returned error is reported to users. +func checkValidHTTP2RequestHeaders(h http.Header) error { + for _, k := range connHeaders { + if _, ok := h[k]; ok { + return fmt.Errorf("request header %q is not valid in HTTP/2", k) + } + } + te := h["Te"] + if len(te) > 0 && (len(te) > 1 || (te[0] != "trailers" && te[0] != "")) { + return errors.New(`request header "TE" may only be "trailers" in HTTP/2`) + } + return nil +} + +func new400Handler(err error) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + http.Error(w, err.Error(), http.StatusBadRequest) + } +} + +// h1ServerKeepAlivesDisabled reports whether hs has its keep-alives +// disabled. See comments on h1ServerShutdownChan above for why +// the code is written this way. +func h1ServerKeepAlivesDisabled(hs *http.Server) bool { + var x interface{} = hs + type I interface { + doKeepAlives() bool + } + if hs, ok := x.(I); ok { + return !hs.doKeepAlives() + } + return false +} |