blob: 514c126c5f8f297fe91b04839b37e89c430c08be [file] [log] [blame]
Matteo Scandoloa4285862020-12-01 18:10:10 -08001// Copyright 2014 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package http2
6
7import (
8 "bytes"
9 "encoding/binary"
10 "errors"
11 "fmt"
12 "io"
13 "log"
14 "strings"
15 "sync"
16
17 "golang.org/x/net/http/httpguts"
18 "golang.org/x/net/http2/hpack"
19)
20
21const frameHeaderLen = 9
22
23var padZeros = make([]byte, 255) // zeros for padding
24
25// A FrameType is a registered frame type as defined in
26// http://http2.github.io/http2-spec/#rfc.section.11.2
27type FrameType uint8
28
29const (
30 FrameData FrameType = 0x0
31 FrameHeaders FrameType = 0x1
32 FramePriority FrameType = 0x2
33 FrameRSTStream FrameType = 0x3
34 FrameSettings FrameType = 0x4
35 FramePushPromise FrameType = 0x5
36 FramePing FrameType = 0x6
37 FrameGoAway FrameType = 0x7
38 FrameWindowUpdate FrameType = 0x8
39 FrameContinuation FrameType = 0x9
40)
41
42var frameName = map[FrameType]string{
43 FrameData: "DATA",
44 FrameHeaders: "HEADERS",
45 FramePriority: "PRIORITY",
46 FrameRSTStream: "RST_STREAM",
47 FrameSettings: "SETTINGS",
48 FramePushPromise: "PUSH_PROMISE",
49 FramePing: "PING",
50 FrameGoAway: "GOAWAY",
51 FrameWindowUpdate: "WINDOW_UPDATE",
52 FrameContinuation: "CONTINUATION",
53}
54
55func (t FrameType) String() string {
56 if s, ok := frameName[t]; ok {
57 return s
58 }
59 return fmt.Sprintf("UNKNOWN_FRAME_TYPE_%d", uint8(t))
60}
61
62// Flags is a bitmask of HTTP/2 flags.
63// The meaning of flags varies depending on the frame type.
64type Flags uint8
65
66// Has reports whether f contains all (0 or more) flags in v.
67func (f Flags) Has(v Flags) bool {
68 return (f & v) == v
69}
70
71// Frame-specific FrameHeader flag bits.
72const (
73 // Data Frame
74 FlagDataEndStream Flags = 0x1
75 FlagDataPadded Flags = 0x8
76
77 // Headers Frame
78 FlagHeadersEndStream Flags = 0x1
79 FlagHeadersEndHeaders Flags = 0x4
80 FlagHeadersPadded Flags = 0x8
81 FlagHeadersPriority Flags = 0x20
82
83 // Settings Frame
84 FlagSettingsAck Flags = 0x1
85
86 // Ping Frame
87 FlagPingAck Flags = 0x1
88
89 // Continuation Frame
90 FlagContinuationEndHeaders Flags = 0x4
91
92 FlagPushPromiseEndHeaders Flags = 0x4
93 FlagPushPromisePadded Flags = 0x8
94)
95
96var flagName = map[FrameType]map[Flags]string{
97 FrameData: {
98 FlagDataEndStream: "END_STREAM",
99 FlagDataPadded: "PADDED",
100 },
101 FrameHeaders: {
102 FlagHeadersEndStream: "END_STREAM",
103 FlagHeadersEndHeaders: "END_HEADERS",
104 FlagHeadersPadded: "PADDED",
105 FlagHeadersPriority: "PRIORITY",
106 },
107 FrameSettings: {
108 FlagSettingsAck: "ACK",
109 },
110 FramePing: {
111 FlagPingAck: "ACK",
112 },
113 FrameContinuation: {
114 FlagContinuationEndHeaders: "END_HEADERS",
115 },
116 FramePushPromise: {
117 FlagPushPromiseEndHeaders: "END_HEADERS",
118 FlagPushPromisePadded: "PADDED",
119 },
120}
121
122// a frameParser parses a frame given its FrameHeader and payload
123// bytes. The length of payload will always equal fh.Length (which
124// might be 0).
125type frameParser func(fc *frameCache, fh FrameHeader, payload []byte) (Frame, error)
126
127var frameParsers = map[FrameType]frameParser{
128 FrameData: parseDataFrame,
129 FrameHeaders: parseHeadersFrame,
130 FramePriority: parsePriorityFrame,
131 FrameRSTStream: parseRSTStreamFrame,
132 FrameSettings: parseSettingsFrame,
133 FramePushPromise: parsePushPromise,
134 FramePing: parsePingFrame,
135 FrameGoAway: parseGoAwayFrame,
136 FrameWindowUpdate: parseWindowUpdateFrame,
137 FrameContinuation: parseContinuationFrame,
138}
139
140func typeFrameParser(t FrameType) frameParser {
141 if f := frameParsers[t]; f != nil {
142 return f
143 }
144 return parseUnknownFrame
145}
146
147// A FrameHeader is the 9 byte header of all HTTP/2 frames.
148//
149// See http://http2.github.io/http2-spec/#FrameHeader
150type FrameHeader struct {
151 valid bool // caller can access []byte fields in the Frame
152
153 // Type is the 1 byte frame type. There are ten standard frame
154 // types, but extension frame types may be written by WriteRawFrame
155 // and will be returned by ReadFrame (as UnknownFrame).
156 Type FrameType
157
158 // Flags are the 1 byte of 8 potential bit flags per frame.
159 // They are specific to the frame type.
160 Flags Flags
161
162 // Length is the length of the frame, not including the 9 byte header.
163 // The maximum size is one byte less than 16MB (uint24), but only
164 // frames up to 16KB are allowed without peer agreement.
165 Length uint32
166
167 // StreamID is which stream this frame is for. Certain frames
168 // are not stream-specific, in which case this field is 0.
169 StreamID uint32
170}
171
172// Header returns h. It exists so FrameHeaders can be embedded in other
173// specific frame types and implement the Frame interface.
174func (h FrameHeader) Header() FrameHeader { return h }
175
176func (h FrameHeader) String() string {
177 var buf bytes.Buffer
178 buf.WriteString("[FrameHeader ")
179 h.writeDebug(&buf)
180 buf.WriteByte(']')
181 return buf.String()
182}
183
184func (h FrameHeader) writeDebug(buf *bytes.Buffer) {
185 buf.WriteString(h.Type.String())
186 if h.Flags != 0 {
187 buf.WriteString(" flags=")
188 set := 0
189 for i := uint8(0); i < 8; i++ {
190 if h.Flags&(1<<i) == 0 {
191 continue
192 }
193 set++
194 if set > 1 {
195 buf.WriteByte('|')
196 }
197 name := flagName[h.Type][Flags(1<<i)]
198 if name != "" {
199 buf.WriteString(name)
200 } else {
201 fmt.Fprintf(buf, "0x%x", 1<<i)
202 }
203 }
204 }
205 if h.StreamID != 0 {
206 fmt.Fprintf(buf, " stream=%d", h.StreamID)
207 }
208 fmt.Fprintf(buf, " len=%d", h.Length)
209}
210
211func (h *FrameHeader) checkValid() {
212 if !h.valid {
213 panic("Frame accessor called on non-owned Frame")
214 }
215}
216
217func (h *FrameHeader) invalidate() { h.valid = false }
218
219// frame header bytes.
220// Used only by ReadFrameHeader.
221var fhBytes = sync.Pool{
222 New: func() interface{} {
223 buf := make([]byte, frameHeaderLen)
224 return &buf
225 },
226}
227
228// ReadFrameHeader reads 9 bytes from r and returns a FrameHeader.
229// Most users should use Framer.ReadFrame instead.
230func ReadFrameHeader(r io.Reader) (FrameHeader, error) {
231 bufp := fhBytes.Get().(*[]byte)
232 defer fhBytes.Put(bufp)
233 return readFrameHeader(*bufp, r)
234}
235
236func readFrameHeader(buf []byte, r io.Reader) (FrameHeader, error) {
237 _, err := io.ReadFull(r, buf[:frameHeaderLen])
238 if err != nil {
239 return FrameHeader{}, err
240 }
241 return FrameHeader{
242 Length: (uint32(buf[0])<<16 | uint32(buf[1])<<8 | uint32(buf[2])),
243 Type: FrameType(buf[3]),
244 Flags: Flags(buf[4]),
245 StreamID: binary.BigEndian.Uint32(buf[5:]) & (1<<31 - 1),
246 valid: true,
247 }, nil
248}
249
250// A Frame is the base interface implemented by all frame types.
251// Callers will generally type-assert the specific frame type:
252// *HeadersFrame, *SettingsFrame, *WindowUpdateFrame, etc.
253//
254// Frames are only valid until the next call to Framer.ReadFrame.
255type Frame interface {
256 Header() FrameHeader
257
258 // invalidate is called by Framer.ReadFrame to make this
259 // frame's buffers as being invalid, since the subsequent
260 // frame will reuse them.
261 invalidate()
262}
263
264// A Framer reads and writes Frames.
265type Framer struct {
266 r io.Reader
267 lastFrame Frame
268 errDetail error
269
270 // lastHeaderStream is non-zero if the last frame was an
271 // unfinished HEADERS/CONTINUATION.
272 lastHeaderStream uint32
273
274 maxReadSize uint32
275 headerBuf [frameHeaderLen]byte
276
277 // TODO: let getReadBuf be configurable, and use a less memory-pinning
278 // allocator in server.go to minimize memory pinned for many idle conns.
279 // Will probably also need to make frame invalidation have a hook too.
280 getReadBuf func(size uint32) []byte
281 readBuf []byte // cache for default getReadBuf
282
283 maxWriteSize uint32 // zero means unlimited; TODO: implement
284
285 w io.Writer
286 wbuf []byte
287
288 // AllowIllegalWrites permits the Framer's Write methods to
289 // write frames that do not conform to the HTTP/2 spec. This
290 // permits using the Framer to test other HTTP/2
291 // implementations' conformance to the spec.
292 // If false, the Write methods will prefer to return an error
293 // rather than comply.
294 AllowIllegalWrites bool
295
296 // AllowIllegalReads permits the Framer's ReadFrame method
297 // to return non-compliant frames or frame orders.
298 // This is for testing and permits using the Framer to test
299 // other HTTP/2 implementations' conformance to the spec.
300 // It is not compatible with ReadMetaHeaders.
301 AllowIllegalReads bool
302
303 // ReadMetaHeaders if non-nil causes ReadFrame to merge
304 // HEADERS and CONTINUATION frames together and return
305 // MetaHeadersFrame instead.
306 ReadMetaHeaders *hpack.Decoder
307
308 // MaxHeaderListSize is the http2 MAX_HEADER_LIST_SIZE.
309 // It's used only if ReadMetaHeaders is set; 0 means a sane default
310 // (currently 16MB)
311 // If the limit is hit, MetaHeadersFrame.Truncated is set true.
312 MaxHeaderListSize uint32
313
314 // TODO: track which type of frame & with which flags was sent
315 // last. Then return an error (unless AllowIllegalWrites) if
316 // we're in the middle of a header block and a
317 // non-Continuation or Continuation on a different stream is
318 // attempted to be written.
319
320 logReads, logWrites bool
321
322 debugFramer *Framer // only use for logging written writes
323 debugFramerBuf *bytes.Buffer
324 debugReadLoggerf func(string, ...interface{})
325 debugWriteLoggerf func(string, ...interface{})
326
327 frameCache *frameCache // nil if frames aren't reused (default)
328}
329
330func (fr *Framer) maxHeaderListSize() uint32 {
331 if fr.MaxHeaderListSize == 0 {
332 return 16 << 20 // sane default, per docs
333 }
334 return fr.MaxHeaderListSize
335}
336
337func (f *Framer) startWrite(ftype FrameType, flags Flags, streamID uint32) {
338 // Write the FrameHeader.
339 f.wbuf = append(f.wbuf[:0],
340 0, // 3 bytes of length, filled in in endWrite
341 0,
342 0,
343 byte(ftype),
344 byte(flags),
345 byte(streamID>>24),
346 byte(streamID>>16),
347 byte(streamID>>8),
348 byte(streamID))
349}
350
351func (f *Framer) endWrite() error {
352 // Now that we know the final size, fill in the FrameHeader in
353 // the space previously reserved for it. Abuse append.
354 length := len(f.wbuf) - frameHeaderLen
355 if length >= (1 << 24) {
356 return ErrFrameTooLarge
357 }
358 _ = append(f.wbuf[:0],
359 byte(length>>16),
360 byte(length>>8),
361 byte(length))
362 if f.logWrites {
363 f.logWrite()
364 }
365
366 n, err := f.w.Write(f.wbuf)
367 if err == nil && n != len(f.wbuf) {
368 err = io.ErrShortWrite
369 }
370 return err
371}
372
373func (f *Framer) logWrite() {
374 if f.debugFramer == nil {
375 f.debugFramerBuf = new(bytes.Buffer)
376 f.debugFramer = NewFramer(nil, f.debugFramerBuf)
377 f.debugFramer.logReads = false // we log it ourselves, saying "wrote" below
378 // Let us read anything, even if we accidentally wrote it
379 // in the wrong order:
380 f.debugFramer.AllowIllegalReads = true
381 }
382 f.debugFramerBuf.Write(f.wbuf)
383 fr, err := f.debugFramer.ReadFrame()
384 if err != nil {
385 f.debugWriteLoggerf("http2: Framer %p: failed to decode just-written frame", f)
386 return
387 }
388 f.debugWriteLoggerf("http2: Framer %p: wrote %v", f, summarizeFrame(fr))
389}
390
391func (f *Framer) writeByte(v byte) { f.wbuf = append(f.wbuf, v) }
392func (f *Framer) writeBytes(v []byte) { f.wbuf = append(f.wbuf, v...) }
393func (f *Framer) writeUint16(v uint16) { f.wbuf = append(f.wbuf, byte(v>>8), byte(v)) }
394func (f *Framer) writeUint32(v uint32) {
395 f.wbuf = append(f.wbuf, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
396}
397
398const (
399 minMaxFrameSize = 1 << 14
400 maxFrameSize = 1<<24 - 1
401)
402
403// SetReuseFrames allows the Framer to reuse Frames.
404// If called on a Framer, Frames returned by calls to ReadFrame are only
405// valid until the next call to ReadFrame.
406func (fr *Framer) SetReuseFrames() {
407 if fr.frameCache != nil {
408 return
409 }
410 fr.frameCache = &frameCache{}
411}
412
413type frameCache struct {
414 dataFrame DataFrame
415}
416
417func (fc *frameCache) getDataFrame() *DataFrame {
418 if fc == nil {
419 return &DataFrame{}
420 }
421 return &fc.dataFrame
422}
423
424// NewFramer returns a Framer that writes frames to w and reads them from r.
425func NewFramer(w io.Writer, r io.Reader) *Framer {
426 fr := &Framer{
427 w: w,
428 r: r,
429 logReads: logFrameReads,
430 logWrites: logFrameWrites,
431 debugReadLoggerf: log.Printf,
432 debugWriteLoggerf: log.Printf,
433 }
434 fr.getReadBuf = func(size uint32) []byte {
435 if cap(fr.readBuf) >= int(size) {
436 return fr.readBuf[:size]
437 }
438 fr.readBuf = make([]byte, size)
439 return fr.readBuf
440 }
441 fr.SetMaxReadFrameSize(maxFrameSize)
442 return fr
443}
444
445// SetMaxReadFrameSize sets the maximum size of a frame
446// that will be read by a subsequent call to ReadFrame.
447// It is the caller's responsibility to advertise this
448// limit with a SETTINGS frame.
449func (fr *Framer) SetMaxReadFrameSize(v uint32) {
450 if v > maxFrameSize {
451 v = maxFrameSize
452 }
453 fr.maxReadSize = v
454}
455
456// ErrorDetail returns a more detailed error of the last error
457// returned by Framer.ReadFrame. For instance, if ReadFrame
458// returns a StreamError with code PROTOCOL_ERROR, ErrorDetail
459// will say exactly what was invalid. ErrorDetail is not guaranteed
460// to return a non-nil value and like the rest of the http2 package,
461// its return value is not protected by an API compatibility promise.
462// ErrorDetail is reset after the next call to ReadFrame.
463func (fr *Framer) ErrorDetail() error {
464 return fr.errDetail
465}
466
467// ErrFrameTooLarge is returned from Framer.ReadFrame when the peer
468// sends a frame that is larger than declared with SetMaxReadFrameSize.
469var ErrFrameTooLarge = errors.New("http2: frame too large")
470
471// terminalReadFrameError reports whether err is an unrecoverable
472// error from ReadFrame and no other frames should be read.
473func terminalReadFrameError(err error) bool {
474 if _, ok := err.(StreamError); ok {
475 return false
476 }
477 return err != nil
478}
479
480// ReadFrame reads a single frame. The returned Frame is only valid
481// until the next call to ReadFrame.
482//
483// If the frame is larger than previously set with SetMaxReadFrameSize, the
484// returned error is ErrFrameTooLarge. Other errors may be of type
485// ConnectionError, StreamError, or anything else from the underlying
486// reader.
487func (fr *Framer) ReadFrame() (Frame, error) {
488 fr.errDetail = nil
489 if fr.lastFrame != nil {
490 fr.lastFrame.invalidate()
491 }
492 fh, err := readFrameHeader(fr.headerBuf[:], fr.r)
493 if err != nil {
494 return nil, err
495 }
496 if fh.Length > fr.maxReadSize {
497 return nil, ErrFrameTooLarge
498 }
499 payload := fr.getReadBuf(fh.Length)
500 if _, err := io.ReadFull(fr.r, payload); err != nil {
501 return nil, err
502 }
503 f, err := typeFrameParser(fh.Type)(fr.frameCache, fh, payload)
504 if err != nil {
505 if ce, ok := err.(connError); ok {
506 return nil, fr.connError(ce.Code, ce.Reason)
507 }
508 return nil, err
509 }
510 if err := fr.checkFrameOrder(f); err != nil {
511 return nil, err
512 }
513 if fr.logReads {
514 fr.debugReadLoggerf("http2: Framer %p: read %v", fr, summarizeFrame(f))
515 }
516 if fh.Type == FrameHeaders && fr.ReadMetaHeaders != nil {
517 return fr.readMetaFrame(f.(*HeadersFrame))
518 }
519 return f, nil
520}
521
522// connError returns ConnectionError(code) but first
523// stashes away a public reason to the caller can optionally relay it
524// to the peer before hanging up on them. This might help others debug
525// their implementations.
526func (fr *Framer) connError(code ErrCode, reason string) error {
527 fr.errDetail = errors.New(reason)
528 return ConnectionError(code)
529}
530
531// checkFrameOrder reports an error if f is an invalid frame to return
532// next from ReadFrame. Mostly it checks whether HEADERS and
533// CONTINUATION frames are contiguous.
534func (fr *Framer) checkFrameOrder(f Frame) error {
535 last := fr.lastFrame
536 fr.lastFrame = f
537 if fr.AllowIllegalReads {
538 return nil
539 }
540
541 fh := f.Header()
542 if fr.lastHeaderStream != 0 {
543 if fh.Type != FrameContinuation {
544 return fr.connError(ErrCodeProtocol,
545 fmt.Sprintf("got %s for stream %d; expected CONTINUATION following %s for stream %d",
546 fh.Type, fh.StreamID,
547 last.Header().Type, fr.lastHeaderStream))
548 }
549 if fh.StreamID != fr.lastHeaderStream {
550 return fr.connError(ErrCodeProtocol,
551 fmt.Sprintf("got CONTINUATION for stream %d; expected stream %d",
552 fh.StreamID, fr.lastHeaderStream))
553 }
554 } else if fh.Type == FrameContinuation {
555 return fr.connError(ErrCodeProtocol, fmt.Sprintf("unexpected CONTINUATION for stream %d", fh.StreamID))
556 }
557
558 switch fh.Type {
559 case FrameHeaders, FrameContinuation:
560 if fh.Flags.Has(FlagHeadersEndHeaders) {
561 fr.lastHeaderStream = 0
562 } else {
563 fr.lastHeaderStream = fh.StreamID
564 }
565 }
566
567 return nil
568}
569
570// A DataFrame conveys arbitrary, variable-length sequences of octets
571// associated with a stream.
572// See http://http2.github.io/http2-spec/#rfc.section.6.1
573type DataFrame struct {
574 FrameHeader
575 data []byte
576}
577
578func (f *DataFrame) StreamEnded() bool {
579 return f.FrameHeader.Flags.Has(FlagDataEndStream)
580}
581
582// Data returns the frame's data octets, not including any padding
583// size byte or padding suffix bytes.
584// The caller must not retain the returned memory past the next
585// call to ReadFrame.
586func (f *DataFrame) Data() []byte {
587 f.checkValid()
588 return f.data
589}
590
591func parseDataFrame(fc *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
592 if fh.StreamID == 0 {
593 // DATA frames MUST be associated with a stream. If a
594 // DATA frame is received whose stream identifier
595 // field is 0x0, the recipient MUST respond with a
596 // connection error (Section 5.4.1) of type
597 // PROTOCOL_ERROR.
598 return nil, connError{ErrCodeProtocol, "DATA frame with stream ID 0"}
599 }
600 f := fc.getDataFrame()
601 f.FrameHeader = fh
602
603 var padSize byte
604 if fh.Flags.Has(FlagDataPadded) {
605 var err error
606 payload, padSize, err = readByte(payload)
607 if err != nil {
608 return nil, err
609 }
610 }
611 if int(padSize) > len(payload) {
612 // If the length of the padding is greater than the
613 // length of the frame payload, the recipient MUST
614 // treat this as a connection error.
615 // Filed: https://github.com/http2/http2-spec/issues/610
616 return nil, connError{ErrCodeProtocol, "pad size larger than data payload"}
617 }
618 f.data = payload[:len(payload)-int(padSize)]
619 return f, nil
620}
621
622var (
623 errStreamID = errors.New("invalid stream ID")
624 errDepStreamID = errors.New("invalid dependent stream ID")
625 errPadLength = errors.New("pad length too large")
626 errPadBytes = errors.New("padding bytes must all be zeros unless AllowIllegalWrites is enabled")
627)
628
629func validStreamIDOrZero(streamID uint32) bool {
630 return streamID&(1<<31) == 0
631}
632
633func validStreamID(streamID uint32) bool {
634 return streamID != 0 && streamID&(1<<31) == 0
635}
636
637// WriteData writes a DATA frame.
638//
639// It will perform exactly one Write to the underlying Writer.
640// It is the caller's responsibility not to violate the maximum frame size
641// and to not call other Write methods concurrently.
642func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error {
643 return f.WriteDataPadded(streamID, endStream, data, nil)
644}
645
646// WriteDataPadded writes a DATA frame with optional padding.
647//
648// If pad is nil, the padding bit is not sent.
649// The length of pad must not exceed 255 bytes.
650// The bytes of pad must all be zero, unless f.AllowIllegalWrites is set.
651//
652// It will perform exactly one Write to the underlying Writer.
653// It is the caller's responsibility not to violate the maximum frame size
654// and to not call other Write methods concurrently.
655func (f *Framer) WriteDataPadded(streamID uint32, endStream bool, data, pad []byte) error {
656 if !validStreamID(streamID) && !f.AllowIllegalWrites {
657 return errStreamID
658 }
659 if len(pad) > 0 {
660 if len(pad) > 255 {
661 return errPadLength
662 }
663 if !f.AllowIllegalWrites {
664 for _, b := range pad {
665 if b != 0 {
666 // "Padding octets MUST be set to zero when sending."
667 return errPadBytes
668 }
669 }
670 }
671 }
672 var flags Flags
673 if endStream {
674 flags |= FlagDataEndStream
675 }
676 if pad != nil {
677 flags |= FlagDataPadded
678 }
679 f.startWrite(FrameData, flags, streamID)
680 if pad != nil {
681 f.wbuf = append(f.wbuf, byte(len(pad)))
682 }
683 f.wbuf = append(f.wbuf, data...)
684 f.wbuf = append(f.wbuf, pad...)
685 return f.endWrite()
686}
687
688// A SettingsFrame conveys configuration parameters that affect how
689// endpoints communicate, such as preferences and constraints on peer
690// behavior.
691//
692// See http://http2.github.io/http2-spec/#SETTINGS
693type SettingsFrame struct {
694 FrameHeader
695 p []byte
696}
697
698func parseSettingsFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
699 if fh.Flags.Has(FlagSettingsAck) && fh.Length > 0 {
700 // When this (ACK 0x1) bit is set, the payload of the
701 // SETTINGS frame MUST be empty. Receipt of a
702 // SETTINGS frame with the ACK flag set and a length
703 // field value other than 0 MUST be treated as a
704 // connection error (Section 5.4.1) of type
705 // FRAME_SIZE_ERROR.
706 return nil, ConnectionError(ErrCodeFrameSize)
707 }
708 if fh.StreamID != 0 {
709 // SETTINGS frames always apply to a connection,
710 // never a single stream. The stream identifier for a
711 // SETTINGS frame MUST be zero (0x0). If an endpoint
712 // receives a SETTINGS frame whose stream identifier
713 // field is anything other than 0x0, the endpoint MUST
714 // respond with a connection error (Section 5.4.1) of
715 // type PROTOCOL_ERROR.
716 return nil, ConnectionError(ErrCodeProtocol)
717 }
718 if len(p)%6 != 0 {
719 // Expecting even number of 6 byte settings.
720 return nil, ConnectionError(ErrCodeFrameSize)
721 }
722 f := &SettingsFrame{FrameHeader: fh, p: p}
723 if v, ok := f.Value(SettingInitialWindowSize); ok && v > (1<<31)-1 {
724 // Values above the maximum flow control window size of 2^31 - 1 MUST
725 // be treated as a connection error (Section 5.4.1) of type
726 // FLOW_CONTROL_ERROR.
727 return nil, ConnectionError(ErrCodeFlowControl)
728 }
729 return f, nil
730}
731
732func (f *SettingsFrame) IsAck() bool {
733 return f.FrameHeader.Flags.Has(FlagSettingsAck)
734}
735
736func (f *SettingsFrame) Value(id SettingID) (v uint32, ok bool) {
737 f.checkValid()
738 for i := 0; i < f.NumSettings(); i++ {
739 if s := f.Setting(i); s.ID == id {
740 return s.Val, true
741 }
742 }
743 return 0, false
744}
745
746// Setting returns the setting from the frame at the given 0-based index.
747// The index must be >= 0 and less than f.NumSettings().
748func (f *SettingsFrame) Setting(i int) Setting {
749 buf := f.p
750 return Setting{
751 ID: SettingID(binary.BigEndian.Uint16(buf[i*6 : i*6+2])),
752 Val: binary.BigEndian.Uint32(buf[i*6+2 : i*6+6]),
753 }
754}
755
756func (f *SettingsFrame) NumSettings() int { return len(f.p) / 6 }
757
758// HasDuplicates reports whether f contains any duplicate setting IDs.
759func (f *SettingsFrame) HasDuplicates() bool {
760 num := f.NumSettings()
761 if num == 0 {
762 return false
763 }
764 // If it's small enough (the common case), just do the n^2
765 // thing and avoid a map allocation.
766 if num < 10 {
767 for i := 0; i < num; i++ {
768 idi := f.Setting(i).ID
769 for j := i + 1; j < num; j++ {
770 idj := f.Setting(j).ID
771 if idi == idj {
772 return true
773 }
774 }
775 }
776 return false
777 }
778 seen := map[SettingID]bool{}
779 for i := 0; i < num; i++ {
780 id := f.Setting(i).ID
781 if seen[id] {
782 return true
783 }
784 seen[id] = true
785 }
786 return false
787}
788
789// ForeachSetting runs fn for each setting.
790// It stops and returns the first error.
791func (f *SettingsFrame) ForeachSetting(fn func(Setting) error) error {
792 f.checkValid()
793 for i := 0; i < f.NumSettings(); i++ {
794 if err := fn(f.Setting(i)); err != nil {
795 return err
796 }
797 }
798 return nil
799}
800
801// WriteSettings writes a SETTINGS frame with zero or more settings
802// specified and the ACK bit not set.
803//
804// It will perform exactly one Write to the underlying Writer.
805// It is the caller's responsibility to not call other Write methods concurrently.
806func (f *Framer) WriteSettings(settings ...Setting) error {
807 f.startWrite(FrameSettings, 0, 0)
808 for _, s := range settings {
809 f.writeUint16(uint16(s.ID))
810 f.writeUint32(s.Val)
811 }
812 return f.endWrite()
813}
814
815// WriteSettingsAck writes an empty SETTINGS frame with the ACK bit set.
816//
817// It will perform exactly one Write to the underlying Writer.
818// It is the caller's responsibility to not call other Write methods concurrently.
819func (f *Framer) WriteSettingsAck() error {
820 f.startWrite(FrameSettings, FlagSettingsAck, 0)
821 return f.endWrite()
822}
823
824// A PingFrame is a mechanism for measuring a minimal round trip time
825// from the sender, as well as determining whether an idle connection
826// is still functional.
827// See http://http2.github.io/http2-spec/#rfc.section.6.7
828type PingFrame struct {
829 FrameHeader
830 Data [8]byte
831}
832
833func (f *PingFrame) IsAck() bool { return f.Flags.Has(FlagPingAck) }
834
835func parsePingFrame(_ *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
836 if len(payload) != 8 {
837 return nil, ConnectionError(ErrCodeFrameSize)
838 }
839 if fh.StreamID != 0 {
840 return nil, ConnectionError(ErrCodeProtocol)
841 }
842 f := &PingFrame{FrameHeader: fh}
843 copy(f.Data[:], payload)
844 return f, nil
845}
846
847func (f *Framer) WritePing(ack bool, data [8]byte) error {
848 var flags Flags
849 if ack {
850 flags = FlagPingAck
851 }
852 f.startWrite(FramePing, flags, 0)
853 f.writeBytes(data[:])
854 return f.endWrite()
855}
856
857// A GoAwayFrame informs the remote peer to stop creating streams on this connection.
858// See http://http2.github.io/http2-spec/#rfc.section.6.8
859type GoAwayFrame struct {
860 FrameHeader
861 LastStreamID uint32
862 ErrCode ErrCode
863 debugData []byte
864}
865
866// DebugData returns any debug data in the GOAWAY frame. Its contents
867// are not defined.
868// The caller must not retain the returned memory past the next
869// call to ReadFrame.
870func (f *GoAwayFrame) DebugData() []byte {
871 f.checkValid()
872 return f.debugData
873}
874
875func parseGoAwayFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
876 if fh.StreamID != 0 {
877 return nil, ConnectionError(ErrCodeProtocol)
878 }
879 if len(p) < 8 {
880 return nil, ConnectionError(ErrCodeFrameSize)
881 }
882 return &GoAwayFrame{
883 FrameHeader: fh,
884 LastStreamID: binary.BigEndian.Uint32(p[:4]) & (1<<31 - 1),
885 ErrCode: ErrCode(binary.BigEndian.Uint32(p[4:8])),
886 debugData: p[8:],
887 }, nil
888}
889
890func (f *Framer) WriteGoAway(maxStreamID uint32, code ErrCode, debugData []byte) error {
891 f.startWrite(FrameGoAway, 0, 0)
892 f.writeUint32(maxStreamID & (1<<31 - 1))
893 f.writeUint32(uint32(code))
894 f.writeBytes(debugData)
895 return f.endWrite()
896}
897
898// An UnknownFrame is the frame type returned when the frame type is unknown
899// or no specific frame type parser exists.
900type UnknownFrame struct {
901 FrameHeader
902 p []byte
903}
904
905// Payload returns the frame's payload (after the header). It is not
906// valid to call this method after a subsequent call to
907// Framer.ReadFrame, nor is it valid to retain the returned slice.
908// The memory is owned by the Framer and is invalidated when the next
909// frame is read.
910func (f *UnknownFrame) Payload() []byte {
911 f.checkValid()
912 return f.p
913}
914
915func parseUnknownFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
916 return &UnknownFrame{fh, p}, nil
917}
918
919// A WindowUpdateFrame is used to implement flow control.
920// See http://http2.github.io/http2-spec/#rfc.section.6.9
921type WindowUpdateFrame struct {
922 FrameHeader
923 Increment uint32 // never read with high bit set
924}
925
926func parseWindowUpdateFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
927 if len(p) != 4 {
928 return nil, ConnectionError(ErrCodeFrameSize)
929 }
930 inc := binary.BigEndian.Uint32(p[:4]) & 0x7fffffff // mask off high reserved bit
931 if inc == 0 {
932 // A receiver MUST treat the receipt of a
933 // WINDOW_UPDATE frame with an flow control window
934 // increment of 0 as a stream error (Section 5.4.2) of
935 // type PROTOCOL_ERROR; errors on the connection flow
936 // control window MUST be treated as a connection
937 // error (Section 5.4.1).
938 if fh.StreamID == 0 {
939 return nil, ConnectionError(ErrCodeProtocol)
940 }
941 return nil, streamError(fh.StreamID, ErrCodeProtocol)
942 }
943 return &WindowUpdateFrame{
944 FrameHeader: fh,
945 Increment: inc,
946 }, nil
947}
948
949// WriteWindowUpdate writes a WINDOW_UPDATE frame.
950// The increment value must be between 1 and 2,147,483,647, inclusive.
951// If the Stream ID is zero, the window update applies to the
952// connection as a whole.
953func (f *Framer) WriteWindowUpdate(streamID, incr uint32) error {
954 // "The legal range for the increment to the flow control window is 1 to 2^31-1 (2,147,483,647) octets."
955 if (incr < 1 || incr > 2147483647) && !f.AllowIllegalWrites {
956 return errors.New("illegal window increment value")
957 }
958 f.startWrite(FrameWindowUpdate, 0, streamID)
959 f.writeUint32(incr)
960 return f.endWrite()
961}
962
963// A HeadersFrame is used to open a stream and additionally carries a
964// header block fragment.
965type HeadersFrame struct {
966 FrameHeader
967
968 // Priority is set if FlagHeadersPriority is set in the FrameHeader.
969 Priority PriorityParam
970
971 headerFragBuf []byte // not owned
972}
973
974func (f *HeadersFrame) HeaderBlockFragment() []byte {
975 f.checkValid()
976 return f.headerFragBuf
977}
978
979func (f *HeadersFrame) HeadersEnded() bool {
980 return f.FrameHeader.Flags.Has(FlagHeadersEndHeaders)
981}
982
983func (f *HeadersFrame) StreamEnded() bool {
984 return f.FrameHeader.Flags.Has(FlagHeadersEndStream)
985}
986
987func (f *HeadersFrame) HasPriority() bool {
988 return f.FrameHeader.Flags.Has(FlagHeadersPriority)
989}
990
991func parseHeadersFrame(_ *frameCache, fh FrameHeader, p []byte) (_ Frame, err error) {
992 hf := &HeadersFrame{
993 FrameHeader: fh,
994 }
995 if fh.StreamID == 0 {
996 // HEADERS frames MUST be associated with a stream. If a HEADERS frame
997 // is received whose stream identifier field is 0x0, the recipient MUST
998 // respond with a connection error (Section 5.4.1) of type
999 // PROTOCOL_ERROR.
1000 return nil, connError{ErrCodeProtocol, "HEADERS frame with stream ID 0"}
1001 }
1002 var padLength uint8
1003 if fh.Flags.Has(FlagHeadersPadded) {
1004 if p, padLength, err = readByte(p); err != nil {
1005 return
1006 }
1007 }
1008 if fh.Flags.Has(FlagHeadersPriority) {
1009 var v uint32
1010 p, v, err = readUint32(p)
1011 if err != nil {
1012 return nil, err
1013 }
1014 hf.Priority.StreamDep = v & 0x7fffffff
1015 hf.Priority.Exclusive = (v != hf.Priority.StreamDep) // high bit was set
1016 p, hf.Priority.Weight, err = readByte(p)
1017 if err != nil {
1018 return nil, err
1019 }
1020 }
1021 if len(p)-int(padLength) <= 0 {
1022 return nil, streamError(fh.StreamID, ErrCodeProtocol)
1023 }
1024 hf.headerFragBuf = p[:len(p)-int(padLength)]
1025 return hf, nil
1026}
1027
1028// HeadersFrameParam are the parameters for writing a HEADERS frame.
1029type HeadersFrameParam struct {
1030 // StreamID is the required Stream ID to initiate.
1031 StreamID uint32
1032 // BlockFragment is part (or all) of a Header Block.
1033 BlockFragment []byte
1034
1035 // EndStream indicates that the header block is the last that
1036 // the endpoint will send for the identified stream. Setting
1037 // this flag causes the stream to enter one of "half closed"
1038 // states.
1039 EndStream bool
1040
1041 // EndHeaders indicates that this frame contains an entire
1042 // header block and is not followed by any
1043 // CONTINUATION frames.
1044 EndHeaders bool
1045
1046 // PadLength is the optional number of bytes of zeros to add
1047 // to this frame.
1048 PadLength uint8
1049
1050 // Priority, if non-zero, includes stream priority information
1051 // in the HEADER frame.
1052 Priority PriorityParam
1053}
1054
1055// WriteHeaders writes a single HEADERS frame.
1056//
1057// This is a low-level header writing method. Encoding headers and
1058// splitting them into any necessary CONTINUATION frames is handled
1059// elsewhere.
1060//
1061// It will perform exactly one Write to the underlying Writer.
1062// It is the caller's responsibility to not call other Write methods concurrently.
1063func (f *Framer) WriteHeaders(p HeadersFrameParam) error {
1064 if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
1065 return errStreamID
1066 }
1067 var flags Flags
1068 if p.PadLength != 0 {
1069 flags |= FlagHeadersPadded
1070 }
1071 if p.EndStream {
1072 flags |= FlagHeadersEndStream
1073 }
1074 if p.EndHeaders {
1075 flags |= FlagHeadersEndHeaders
1076 }
1077 if !p.Priority.IsZero() {
1078 flags |= FlagHeadersPriority
1079 }
1080 f.startWrite(FrameHeaders, flags, p.StreamID)
1081 if p.PadLength != 0 {
1082 f.writeByte(p.PadLength)
1083 }
1084 if !p.Priority.IsZero() {
1085 v := p.Priority.StreamDep
1086 if !validStreamIDOrZero(v) && !f.AllowIllegalWrites {
1087 return errDepStreamID
1088 }
1089 if p.Priority.Exclusive {
1090 v |= 1 << 31
1091 }
1092 f.writeUint32(v)
1093 f.writeByte(p.Priority.Weight)
1094 }
1095 f.wbuf = append(f.wbuf, p.BlockFragment...)
1096 f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
1097 return f.endWrite()
1098}
1099
1100// A PriorityFrame specifies the sender-advised priority of a stream.
1101// See http://http2.github.io/http2-spec/#rfc.section.6.3
1102type PriorityFrame struct {
1103 FrameHeader
1104 PriorityParam
1105}
1106
1107// PriorityParam are the stream prioritzation parameters.
1108type PriorityParam struct {
1109 // StreamDep is a 31-bit stream identifier for the
1110 // stream that this stream depends on. Zero means no
1111 // dependency.
1112 StreamDep uint32
1113
1114 // Exclusive is whether the dependency is exclusive.
1115 Exclusive bool
1116
1117 // Weight is the stream's zero-indexed weight. It should be
1118 // set together with StreamDep, or neither should be set. Per
1119 // the spec, "Add one to the value to obtain a weight between
1120 // 1 and 256."
1121 Weight uint8
1122}
1123
1124func (p PriorityParam) IsZero() bool {
1125 return p == PriorityParam{}
1126}
1127
1128func parsePriorityFrame(_ *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
1129 if fh.StreamID == 0 {
1130 return nil, connError{ErrCodeProtocol, "PRIORITY frame with stream ID 0"}
1131 }
1132 if len(payload) != 5 {
1133 return nil, connError{ErrCodeFrameSize, fmt.Sprintf("PRIORITY frame payload size was %d; want 5", len(payload))}
1134 }
1135 v := binary.BigEndian.Uint32(payload[:4])
1136 streamID := v & 0x7fffffff // mask off high bit
1137 return &PriorityFrame{
1138 FrameHeader: fh,
1139 PriorityParam: PriorityParam{
1140 Weight: payload[4],
1141 StreamDep: streamID,
1142 Exclusive: streamID != v, // was high bit set?
1143 },
1144 }, nil
1145}
1146
1147// WritePriority writes a PRIORITY frame.
1148//
1149// It will perform exactly one Write to the underlying Writer.
1150// It is the caller's responsibility to not call other Write methods concurrently.
1151func (f *Framer) WritePriority(streamID uint32, p PriorityParam) error {
1152 if !validStreamID(streamID) && !f.AllowIllegalWrites {
1153 return errStreamID
1154 }
1155 if !validStreamIDOrZero(p.StreamDep) {
1156 return errDepStreamID
1157 }
1158 f.startWrite(FramePriority, 0, streamID)
1159 v := p.StreamDep
1160 if p.Exclusive {
1161 v |= 1 << 31
1162 }
1163 f.writeUint32(v)
1164 f.writeByte(p.Weight)
1165 return f.endWrite()
1166}
1167
1168// A RSTStreamFrame allows for abnormal termination of a stream.
1169// See http://http2.github.io/http2-spec/#rfc.section.6.4
1170type RSTStreamFrame struct {
1171 FrameHeader
1172 ErrCode ErrCode
1173}
1174
1175func parseRSTStreamFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
1176 if len(p) != 4 {
1177 return nil, ConnectionError(ErrCodeFrameSize)
1178 }
1179 if fh.StreamID == 0 {
1180 return nil, ConnectionError(ErrCodeProtocol)
1181 }
1182 return &RSTStreamFrame{fh, ErrCode(binary.BigEndian.Uint32(p[:4]))}, nil
1183}
1184
1185// WriteRSTStream writes a RST_STREAM frame.
1186//
1187// It will perform exactly one Write to the underlying Writer.
1188// It is the caller's responsibility to not call other Write methods concurrently.
1189func (f *Framer) WriteRSTStream(streamID uint32, code ErrCode) error {
1190 if !validStreamID(streamID) && !f.AllowIllegalWrites {
1191 return errStreamID
1192 }
1193 f.startWrite(FrameRSTStream, 0, streamID)
1194 f.writeUint32(uint32(code))
1195 return f.endWrite()
1196}
1197
1198// A ContinuationFrame is used to continue a sequence of header block fragments.
1199// See http://http2.github.io/http2-spec/#rfc.section.6.10
1200type ContinuationFrame struct {
1201 FrameHeader
1202 headerFragBuf []byte
1203}
1204
1205func parseContinuationFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
1206 if fh.StreamID == 0 {
1207 return nil, connError{ErrCodeProtocol, "CONTINUATION frame with stream ID 0"}
1208 }
1209 return &ContinuationFrame{fh, p}, nil
1210}
1211
1212func (f *ContinuationFrame) HeaderBlockFragment() []byte {
1213 f.checkValid()
1214 return f.headerFragBuf
1215}
1216
1217func (f *ContinuationFrame) HeadersEnded() bool {
1218 return f.FrameHeader.Flags.Has(FlagContinuationEndHeaders)
1219}
1220
1221// WriteContinuation writes a CONTINUATION frame.
1222//
1223// It will perform exactly one Write to the underlying Writer.
1224// It is the caller's responsibility to not call other Write methods concurrently.
1225func (f *Framer) WriteContinuation(streamID uint32, endHeaders bool, headerBlockFragment []byte) error {
1226 if !validStreamID(streamID) && !f.AllowIllegalWrites {
1227 return errStreamID
1228 }
1229 var flags Flags
1230 if endHeaders {
1231 flags |= FlagContinuationEndHeaders
1232 }
1233 f.startWrite(FrameContinuation, flags, streamID)
1234 f.wbuf = append(f.wbuf, headerBlockFragment...)
1235 return f.endWrite()
1236}
1237
1238// A PushPromiseFrame is used to initiate a server stream.
1239// See http://http2.github.io/http2-spec/#rfc.section.6.6
1240type PushPromiseFrame struct {
1241 FrameHeader
1242 PromiseID uint32
1243 headerFragBuf []byte // not owned
1244}
1245
1246func (f *PushPromiseFrame) HeaderBlockFragment() []byte {
1247 f.checkValid()
1248 return f.headerFragBuf
1249}
1250
1251func (f *PushPromiseFrame) HeadersEnded() bool {
1252 return f.FrameHeader.Flags.Has(FlagPushPromiseEndHeaders)
1253}
1254
1255func parsePushPromise(_ *frameCache, fh FrameHeader, p []byte) (_ Frame, err error) {
1256 pp := &PushPromiseFrame{
1257 FrameHeader: fh,
1258 }
1259 if pp.StreamID == 0 {
1260 // PUSH_PROMISE frames MUST be associated with an existing,
1261 // peer-initiated stream. The stream identifier of a
1262 // PUSH_PROMISE frame indicates the stream it is associated
1263 // with. If the stream identifier field specifies the value
1264 // 0x0, a recipient MUST respond with a connection error
1265 // (Section 5.4.1) of type PROTOCOL_ERROR.
1266 return nil, ConnectionError(ErrCodeProtocol)
1267 }
1268 // The PUSH_PROMISE frame includes optional padding.
1269 // Padding fields and flags are identical to those defined for DATA frames
1270 var padLength uint8
1271 if fh.Flags.Has(FlagPushPromisePadded) {
1272 if p, padLength, err = readByte(p); err != nil {
1273 return
1274 }
1275 }
1276
1277 p, pp.PromiseID, err = readUint32(p)
1278 if err != nil {
1279 return
1280 }
1281 pp.PromiseID = pp.PromiseID & (1<<31 - 1)
1282
1283 if int(padLength) > len(p) {
1284 // like the DATA frame, error out if padding is longer than the body.
1285 return nil, ConnectionError(ErrCodeProtocol)
1286 }
1287 pp.headerFragBuf = p[:len(p)-int(padLength)]
1288 return pp, nil
1289}
1290
1291// PushPromiseParam are the parameters for writing a PUSH_PROMISE frame.
1292type PushPromiseParam struct {
1293 // StreamID is the required Stream ID to initiate.
1294 StreamID uint32
1295
1296 // PromiseID is the required Stream ID which this
1297 // Push Promises
1298 PromiseID uint32
1299
1300 // BlockFragment is part (or all) of a Header Block.
1301 BlockFragment []byte
1302
1303 // EndHeaders indicates that this frame contains an entire
1304 // header block and is not followed by any
1305 // CONTINUATION frames.
1306 EndHeaders bool
1307
1308 // PadLength is the optional number of bytes of zeros to add
1309 // to this frame.
1310 PadLength uint8
1311}
1312
1313// WritePushPromise writes a single PushPromise Frame.
1314//
1315// As with Header Frames, This is the low level call for writing
1316// individual frames. Continuation frames are handled elsewhere.
1317//
1318// It will perform exactly one Write to the underlying Writer.
1319// It is the caller's responsibility to not call other Write methods concurrently.
1320func (f *Framer) WritePushPromise(p PushPromiseParam) error {
1321 if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
1322 return errStreamID
1323 }
1324 var flags Flags
1325 if p.PadLength != 0 {
1326 flags |= FlagPushPromisePadded
1327 }
1328 if p.EndHeaders {
1329 flags |= FlagPushPromiseEndHeaders
1330 }
1331 f.startWrite(FramePushPromise, flags, p.StreamID)
1332 if p.PadLength != 0 {
1333 f.writeByte(p.PadLength)
1334 }
1335 if !validStreamID(p.PromiseID) && !f.AllowIllegalWrites {
1336 return errStreamID
1337 }
1338 f.writeUint32(p.PromiseID)
1339 f.wbuf = append(f.wbuf, p.BlockFragment...)
1340 f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
1341 return f.endWrite()
1342}
1343
1344// WriteRawFrame writes a raw frame. This can be used to write
1345// extension frames unknown to this package.
1346func (f *Framer) WriteRawFrame(t FrameType, flags Flags, streamID uint32, payload []byte) error {
1347 f.startWrite(t, flags, streamID)
1348 f.writeBytes(payload)
1349 return f.endWrite()
1350}
1351
1352func readByte(p []byte) (remain []byte, b byte, err error) {
1353 if len(p) == 0 {
1354 return nil, 0, io.ErrUnexpectedEOF
1355 }
1356 return p[1:], p[0], nil
1357}
1358
1359func readUint32(p []byte) (remain []byte, v uint32, err error) {
1360 if len(p) < 4 {
1361 return nil, 0, io.ErrUnexpectedEOF
1362 }
1363 return p[4:], binary.BigEndian.Uint32(p[:4]), nil
1364}
1365
1366type streamEnder interface {
1367 StreamEnded() bool
1368}
1369
1370type headersEnder interface {
1371 HeadersEnded() bool
1372}
1373
1374type headersOrContinuation interface {
1375 headersEnder
1376 HeaderBlockFragment() []byte
1377}
1378
1379// A MetaHeadersFrame is the representation of one HEADERS frame and
1380// zero or more contiguous CONTINUATION frames and the decoding of
1381// their HPACK-encoded contents.
1382//
1383// This type of frame does not appear on the wire and is only returned
1384// by the Framer when Framer.ReadMetaHeaders is set.
1385type MetaHeadersFrame struct {
1386 *HeadersFrame
1387
1388 // Fields are the fields contained in the HEADERS and
1389 // CONTINUATION frames. The underlying slice is owned by the
1390 // Framer and must not be retained after the next call to
1391 // ReadFrame.
1392 //
1393 // Fields are guaranteed to be in the correct http2 order and
1394 // not have unknown pseudo header fields or invalid header
1395 // field names or values. Required pseudo header fields may be
1396 // missing, however. Use the MetaHeadersFrame.Pseudo accessor
1397 // method access pseudo headers.
1398 Fields []hpack.HeaderField
1399
1400 // Truncated is whether the max header list size limit was hit
1401 // and Fields is incomplete. The hpack decoder state is still
1402 // valid, however.
1403 Truncated bool
1404}
1405
1406// PseudoValue returns the given pseudo header field's value.
1407// The provided pseudo field should not contain the leading colon.
1408func (mh *MetaHeadersFrame) PseudoValue(pseudo string) string {
1409 for _, hf := range mh.Fields {
1410 if !hf.IsPseudo() {
1411 return ""
1412 }
1413 if hf.Name[1:] == pseudo {
1414 return hf.Value
1415 }
1416 }
1417 return ""
1418}
1419
1420// RegularFields returns the regular (non-pseudo) header fields of mh.
1421// The caller does not own the returned slice.
1422func (mh *MetaHeadersFrame) RegularFields() []hpack.HeaderField {
1423 for i, hf := range mh.Fields {
1424 if !hf.IsPseudo() {
1425 return mh.Fields[i:]
1426 }
1427 }
1428 return nil
1429}
1430
1431// PseudoFields returns the pseudo header fields of mh.
1432// The caller does not own the returned slice.
1433func (mh *MetaHeadersFrame) PseudoFields() []hpack.HeaderField {
1434 for i, hf := range mh.Fields {
1435 if !hf.IsPseudo() {
1436 return mh.Fields[:i]
1437 }
1438 }
1439 return mh.Fields
1440}
1441
1442func (mh *MetaHeadersFrame) checkPseudos() error {
1443 var isRequest, isResponse bool
1444 pf := mh.PseudoFields()
1445 for i, hf := range pf {
1446 switch hf.Name {
1447 case ":method", ":path", ":scheme", ":authority":
1448 isRequest = true
1449 case ":status":
1450 isResponse = true
1451 default:
1452 return pseudoHeaderError(hf.Name)
1453 }
1454 // Check for duplicates.
1455 // This would be a bad algorithm, but N is 4.
1456 // And this doesn't allocate.
1457 for _, hf2 := range pf[:i] {
1458 if hf.Name == hf2.Name {
1459 return duplicatePseudoHeaderError(hf.Name)
1460 }
1461 }
1462 }
1463 if isRequest && isResponse {
1464 return errMixPseudoHeaderTypes
1465 }
1466 return nil
1467}
1468
1469func (fr *Framer) maxHeaderStringLen() int {
1470 v := fr.maxHeaderListSize()
1471 if uint32(int(v)) == v {
1472 return int(v)
1473 }
1474 // They had a crazy big number for MaxHeaderBytes anyway,
1475 // so give them unlimited header lengths:
1476 return 0
1477}
1478
1479// readMetaFrame returns 0 or more CONTINUATION frames from fr and
1480// merge them into the provided hf and returns a MetaHeadersFrame
1481// with the decoded hpack values.
1482func (fr *Framer) readMetaFrame(hf *HeadersFrame) (*MetaHeadersFrame, error) {
1483 if fr.AllowIllegalReads {
1484 return nil, errors.New("illegal use of AllowIllegalReads with ReadMetaHeaders")
1485 }
1486 mh := &MetaHeadersFrame{
1487 HeadersFrame: hf,
1488 }
1489 var remainSize = fr.maxHeaderListSize()
1490 var sawRegular bool
1491
1492 var invalid error // pseudo header field errors
1493 hdec := fr.ReadMetaHeaders
1494 hdec.SetEmitEnabled(true)
1495 hdec.SetMaxStringLength(fr.maxHeaderStringLen())
1496 hdec.SetEmitFunc(func(hf hpack.HeaderField) {
1497 if VerboseLogs && fr.logReads {
1498 fr.debugReadLoggerf("http2: decoded hpack field %+v", hf)
1499 }
1500 if !httpguts.ValidHeaderFieldValue(hf.Value) {
1501 invalid = headerFieldValueError(hf.Value)
1502 }
1503 isPseudo := strings.HasPrefix(hf.Name, ":")
1504 if isPseudo {
1505 if sawRegular {
1506 invalid = errPseudoAfterRegular
1507 }
1508 } else {
1509 sawRegular = true
1510 if !validWireHeaderFieldName(hf.Name) {
1511 invalid = headerFieldNameError(hf.Name)
1512 }
1513 }
1514
1515 if invalid != nil {
1516 hdec.SetEmitEnabled(false)
1517 return
1518 }
1519
1520 size := hf.Size()
1521 if size > remainSize {
1522 hdec.SetEmitEnabled(false)
1523 mh.Truncated = true
1524 return
1525 }
1526 remainSize -= size
1527
1528 mh.Fields = append(mh.Fields, hf)
1529 })
1530 // Lose reference to MetaHeadersFrame:
1531 defer hdec.SetEmitFunc(func(hf hpack.HeaderField) {})
1532
1533 var hc headersOrContinuation = hf
1534 for {
1535 frag := hc.HeaderBlockFragment()
1536 if _, err := hdec.Write(frag); err != nil {
1537 return nil, ConnectionError(ErrCodeCompression)
1538 }
1539
1540 if hc.HeadersEnded() {
1541 break
1542 }
1543 if f, err := fr.ReadFrame(); err != nil {
1544 return nil, err
1545 } else {
1546 hc = f.(*ContinuationFrame) // guaranteed by checkFrameOrder
1547 }
1548 }
1549
1550 mh.HeadersFrame.headerFragBuf = nil
1551 mh.HeadersFrame.invalidate()
1552
1553 if err := hdec.Close(); err != nil {
1554 return nil, ConnectionError(ErrCodeCompression)
1555 }
1556 if invalid != nil {
1557 fr.errDetail = invalid
1558 if VerboseLogs {
1559 log.Printf("http2: invalid header: %v", invalid)
1560 }
1561 return nil, StreamError{mh.StreamID, ErrCodeProtocol, invalid}
1562 }
1563 if err := mh.checkPseudos(); err != nil {
1564 fr.errDetail = err
1565 if VerboseLogs {
1566 log.Printf("http2: invalid pseudo headers: %v", err)
1567 }
1568 return nil, StreamError{mh.StreamID, ErrCodeProtocol, err}
1569 }
1570 return mh, nil
1571}
1572
1573func summarizeFrame(f Frame) string {
1574 var buf bytes.Buffer
1575 f.Header().writeDebug(&buf)
1576 switch f := f.(type) {
1577 case *SettingsFrame:
1578 n := 0
1579 f.ForeachSetting(func(s Setting) error {
1580 n++
1581 if n == 1 {
1582 buf.WriteString(", settings:")
1583 }
1584 fmt.Fprintf(&buf, " %v=%v,", s.ID, s.Val)
1585 return nil
1586 })
1587 if n > 0 {
1588 buf.Truncate(buf.Len() - 1) // remove trailing comma
1589 }
1590 case *DataFrame:
1591 data := f.Data()
1592 const max = 256
1593 if len(data) > max {
1594 data = data[:max]
1595 }
1596 fmt.Fprintf(&buf, " data=%q", data)
1597 if len(f.Data()) > max {
1598 fmt.Fprintf(&buf, " (%d bytes omitted)", len(f.Data())-max)
1599 }
1600 case *WindowUpdateFrame:
1601 if f.StreamID == 0 {
1602 buf.WriteString(" (conn)")
1603 }
1604 fmt.Fprintf(&buf, " incr=%v", f.Increment)
1605 case *PingFrame:
1606 fmt.Fprintf(&buf, " ping=%q", f.Data[:])
1607 case *GoAwayFrame:
1608 fmt.Fprintf(&buf, " LastStreamID=%v ErrCode=%v Debug=%q",
1609 f.LastStreamID, f.ErrCode, f.debugData)
1610 case *RSTStreamFrame:
1611 fmt.Fprintf(&buf, " ErrCode=%v", f.ErrCode)
1612 }
1613 return buf.String()
1614}