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// 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.
package http2
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"log"
"strings"
"sync"
"golang.org/x/net/http/httpguts"
"golang.org/x/net/http2/hpack"
)
const frameHeaderLen = 9
var padZeros = make([]byte, 255) // zeros for padding
// A FrameType is a registered frame type as defined in
// http://http2.github.io/http2-spec/#rfc.section.11.2
type FrameType uint8
const (
FrameData FrameType = 0x0
FrameHeaders FrameType = 0x1
FramePriority FrameType = 0x2
FrameRSTStream FrameType = 0x3
FrameSettings FrameType = 0x4
FramePushPromise FrameType = 0x5
FramePing FrameType = 0x6
FrameGoAway FrameType = 0x7
FrameWindowUpdate FrameType = 0x8
FrameContinuation FrameType = 0x9
)
var frameName = map[FrameType]string{
FrameData: "DATA",
FrameHeaders: "HEADERS",
FramePriority: "PRIORITY",
FrameRSTStream: "RST_STREAM",
FrameSettings: "SETTINGS",
FramePushPromise: "PUSH_PROMISE",
FramePing: "PING",
FrameGoAway: "GOAWAY",
FrameWindowUpdate: "WINDOW_UPDATE",
FrameContinuation: "CONTINUATION",
}
func (t FrameType) String() string {
if s, ok := frameName[t]; ok {
return s
}
return fmt.Sprintf("UNKNOWN_FRAME_TYPE_%d", uint8(t))
}
// Flags is a bitmask of HTTP/2 flags.
// The meaning of flags varies depending on the frame type.
type Flags uint8
// Has reports whether f contains all (0 or more) flags in v.
func (f Flags) Has(v Flags) bool {
return (f & v) == v
}
// Frame-specific FrameHeader flag bits.
const (
// Data Frame
FlagDataEndStream Flags = 0x1
FlagDataPadded Flags = 0x8
// Headers Frame
FlagHeadersEndStream Flags = 0x1
FlagHeadersEndHeaders Flags = 0x4
FlagHeadersPadded Flags = 0x8
FlagHeadersPriority Flags = 0x20
// Settings Frame
FlagSettingsAck Flags = 0x1
// Ping Frame
FlagPingAck Flags = 0x1
// Continuation Frame
FlagContinuationEndHeaders Flags = 0x4
FlagPushPromiseEndHeaders Flags = 0x4
FlagPushPromisePadded Flags = 0x8
)
var flagName = map[FrameType]map[Flags]string{
FrameData: {
FlagDataEndStream: "END_STREAM",
FlagDataPadded: "PADDED",
},
FrameHeaders: {
FlagHeadersEndStream: "END_STREAM",
FlagHeadersEndHeaders: "END_HEADERS",
FlagHeadersPadded: "PADDED",
FlagHeadersPriority: "PRIORITY",
},
FrameSettings: {
FlagSettingsAck: "ACK",
},
FramePing: {
FlagPingAck: "ACK",
},
FrameContinuation: {
FlagContinuationEndHeaders: "END_HEADERS",
},
FramePushPromise: {
FlagPushPromiseEndHeaders: "END_HEADERS",
FlagPushPromisePadded: "PADDED",
},
}
// a frameParser parses a frame given its FrameHeader and payload
// bytes. The length of payload will always equal fh.Length (which
// might be 0).
type frameParser func(fc *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error)
var frameParsers = map[FrameType]frameParser{
FrameData: parseDataFrame,
FrameHeaders: parseHeadersFrame,
FramePriority: parsePriorityFrame,
FrameRSTStream: parseRSTStreamFrame,
FrameSettings: parseSettingsFrame,
FramePushPromise: parsePushPromise,
FramePing: parsePingFrame,
FrameGoAway: parseGoAwayFrame,
FrameWindowUpdate: parseWindowUpdateFrame,
FrameContinuation: parseContinuationFrame,
}
func typeFrameParser(t FrameType) frameParser {
if f := frameParsers[t]; f != nil {
return f
}
return parseUnknownFrame
}
// A FrameHeader is the 9 byte header of all HTTP/2 frames.
//
// See http://http2.github.io/http2-spec/#FrameHeader
type FrameHeader struct {
valid bool // caller can access []byte fields in the Frame
// Type is the 1 byte frame type. There are ten standard frame
// types, but extension frame types may be written by WriteRawFrame
// and will be returned by ReadFrame (as UnknownFrame).
Type FrameType
// Flags are the 1 byte of 8 potential bit flags per frame.
// They are specific to the frame type.
Flags Flags
// Length is the length of the frame, not including the 9 byte header.
// The maximum size is one byte less than 16MB (uint24), but only
// frames up to 16KB are allowed without peer agreement.
Length uint32
// StreamID is which stream this frame is for. Certain frames
// are not stream-specific, in which case this field is 0.
StreamID uint32
}
// Header returns h. It exists so FrameHeaders can be embedded in other
// specific frame types and implement the Frame interface.
func (h FrameHeader) Header() FrameHeader { return h }
func (h FrameHeader) String() string {
var buf bytes.Buffer
buf.WriteString("[FrameHeader ")
h.writeDebug(&buf)
buf.WriteByte(']')
return buf.String()
}
func (h FrameHeader) writeDebug(buf *bytes.Buffer) {
buf.WriteString(h.Type.String())
if h.Flags != 0 {
buf.WriteString(" flags=")
set := 0
for i := uint8(0); i < 8; i++ {
if h.Flags&(1< 1 {
buf.WriteByte('|')
}
name := flagName[h.Type][Flags(1<>24),
byte(streamID>>16),
byte(streamID>>8),
byte(streamID))
}
func (f *Framer) endWrite() error {
// Now that we know the final size, fill in the FrameHeader in
// the space previously reserved for it. Abuse append.
length := len(f.wbuf) - frameHeaderLen
if length >= (1 << 24) {
return ErrFrameTooLarge
}
_ = append(f.wbuf[:0],
byte(length>>16),
byte(length>>8),
byte(length))
if f.logWrites {
f.logWrite()
}
n, err := f.w.Write(f.wbuf)
if err == nil && n != len(f.wbuf) {
err = io.ErrShortWrite
}
return err
}
func (f *Framer) logWrite() {
if f.debugFramer == nil {
f.debugFramerBuf = new(bytes.Buffer)
f.debugFramer = NewFramer(nil, f.debugFramerBuf)
f.debugFramer.logReads = false // we log it ourselves, saying "wrote" below
// Let us read anything, even if we accidentally wrote it
// in the wrong order:
f.debugFramer.AllowIllegalReads = true
}
f.debugFramerBuf.Write(f.wbuf)
fr, err := f.debugFramer.ReadFrame()
if err != nil {
f.debugWriteLoggerf("http2: Framer %p: failed to decode just-written frame", f)
return
}
f.debugWriteLoggerf("http2: Framer %p: wrote %v", f, summarizeFrame(fr))
}
func (f *Framer) writeByte(v byte) { f.wbuf = append(f.wbuf, v) }
func (f *Framer) writeBytes(v []byte) { f.wbuf = append(f.wbuf, v...) }
func (f *Framer) writeUint16(v uint16) { f.wbuf = append(f.wbuf, byte(v>>8), byte(v)) }
func (f *Framer) writeUint32(v uint32) {
f.wbuf = append(f.wbuf, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
const (
minMaxFrameSize = 1 << 14
maxFrameSize = 1<<24 - 1
)
// SetReuseFrames allows the Framer to reuse Frames.
// If called on a Framer, Frames returned by calls to ReadFrame are only
// valid until the next call to ReadFrame.
func (fr *Framer) SetReuseFrames() {
if fr.frameCache != nil {
return
}
fr.frameCache = &frameCache{}
}
type frameCache struct {
dataFrame DataFrame
}
func (fc *frameCache) getDataFrame() *DataFrame {
if fc == nil {
return &DataFrame{}
}
return &fc.dataFrame
}
// NewFramer returns a Framer that writes frames to w and reads them from r.
func NewFramer(w io.Writer, r io.Reader) *Framer {
fr := &Framer{
w: w,
r: r,
countError: func(string) {},
logReads: logFrameReads,
logWrites: logFrameWrites,
debugReadLoggerf: log.Printf,
debugWriteLoggerf: log.Printf,
}
fr.getReadBuf = func(size uint32) []byte {
if cap(fr.readBuf) >= int(size) {
return fr.readBuf[:size]
}
fr.readBuf = make([]byte, size)
return fr.readBuf
}
fr.SetMaxReadFrameSize(maxFrameSize)
return fr
}
// SetMaxReadFrameSize sets the maximum size of a frame
// that will be read by a subsequent call to ReadFrame.
// It is the caller's responsibility to advertise this
// limit with a SETTINGS frame.
func (fr *Framer) SetMaxReadFrameSize(v uint32) {
if v > maxFrameSize {
v = maxFrameSize
}
fr.maxReadSize = v
}
// ErrorDetail returns a more detailed error of the last error
// returned by Framer.ReadFrame. For instance, if ReadFrame
// returns a StreamError with code PROTOCOL_ERROR, ErrorDetail
// will say exactly what was invalid. ErrorDetail is not guaranteed
// to return a non-nil value and like the rest of the http2 package,
// its return value is not protected by an API compatibility promise.
// ErrorDetail is reset after the next call to ReadFrame.
func (fr *Framer) ErrorDetail() error {
return fr.errDetail
}
// ErrFrameTooLarge is returned from Framer.ReadFrame when the peer
// sends a frame that is larger than declared with SetMaxReadFrameSize.
var ErrFrameTooLarge = errors.New("http2: frame too large")
// terminalReadFrameError reports whether err is an unrecoverable
// error from ReadFrame and no other frames should be read.
func terminalReadFrameError(err error) bool {
if _, ok := err.(StreamError); ok {
return false
}
return err != nil
}
// ReadFrame reads a single frame. The returned Frame is only valid
// until the next call to ReadFrame.
//
// If the frame is larger than previously set with SetMaxReadFrameSize, the
// returned error is ErrFrameTooLarge. Other errors may be of type
// ConnectionError, StreamError, or anything else from the underlying
// reader.
func (fr *Framer) ReadFrame() (Frame, error) {
fr.errDetail = nil
if fr.lastFrame != nil {
fr.lastFrame.invalidate()
}
fh, err := readFrameHeader(fr.headerBuf[:], fr.r)
if err != nil {
return nil, err
}
if fh.Length > fr.maxReadSize {
return nil, ErrFrameTooLarge
}
payload := fr.getReadBuf(fh.Length)
if _, err := io.ReadFull(fr.r, payload); err != nil {
return nil, err
}
f, err := typeFrameParser(fh.Type)(fr.frameCache, fh, fr.countError, payload)
if err != nil {
if ce, ok := err.(connError); ok {
return nil, fr.connError(ce.Code, ce.Reason)
}
return nil, err
}
if err := fr.checkFrameOrder(f); err != nil {
return nil, err
}
if fr.logReads {
fr.debugReadLoggerf("http2: Framer %p: read %v", fr, summarizeFrame(f))
}
if fh.Type == FrameHeaders && fr.ReadMetaHeaders != nil {
return fr.readMetaFrame(f.(*HeadersFrame))
}
return f, nil
}
// connError returns ConnectionError(code) but first
// stashes away a public reason to the caller can optionally relay it
// to the peer before hanging up on them. This might help others debug
// their implementations.
func (fr *Framer) connError(code ErrCode, reason string) error {
fr.errDetail = errors.New(reason)
return ConnectionError(code)
}
// checkFrameOrder reports an error if f is an invalid frame to return
// next from ReadFrame. Mostly it checks whether HEADERS and
// CONTINUATION frames are contiguous.
func (fr *Framer) checkFrameOrder(f Frame) error {
last := fr.lastFrame
fr.lastFrame = f
if fr.AllowIllegalReads {
return nil
}
fh := f.Header()
if fr.lastHeaderStream != 0 {
if fh.Type != FrameContinuation {
return fr.connError(ErrCodeProtocol,
fmt.Sprintf("got %s for stream %d; expected CONTINUATION following %s for stream %d",
fh.Type, fh.StreamID,
last.Header().Type, fr.lastHeaderStream))
}
if fh.StreamID != fr.lastHeaderStream {
return fr.connError(ErrCodeProtocol,
fmt.Sprintf("got CONTINUATION for stream %d; expected stream %d",
fh.StreamID, fr.lastHeaderStream))
}
} else if fh.Type == FrameContinuation {
return fr.connError(ErrCodeProtocol, fmt.Sprintf("unexpected CONTINUATION for stream %d", fh.StreamID))
}
switch fh.Type {
case FrameHeaders, FrameContinuation:
if fh.Flags.Has(FlagHeadersEndHeaders) {
fr.lastHeaderStream = 0
} else {
fr.lastHeaderStream = fh.StreamID
}
}
return nil
}
// A DataFrame conveys arbitrary, variable-length sequences of octets
// associated with a stream.
// See http://http2.github.io/http2-spec/#rfc.section.6.1
type DataFrame struct {
FrameHeader
data []byte
}
func (f *DataFrame) StreamEnded() bool {
return f.FrameHeader.Flags.Has(FlagDataEndStream)
}
// Data returns the frame's data octets, not including any padding
// size byte or padding suffix bytes.
// The caller must not retain the returned memory past the next
// call to ReadFrame.
func (f *DataFrame) Data() []byte {
f.checkValid()
return f.data
}
func parseDataFrame(fc *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
if fh.StreamID == 0 {
// DATA frames MUST be associated with a stream. If a
// DATA frame is received whose stream identifier
// field is 0x0, the recipient MUST respond with a
// connection error (Section 5.4.1) of type
// PROTOCOL_ERROR.
countError("frame_data_stream_0")
return nil, connError{ErrCodeProtocol, "DATA frame with stream ID 0"}
}
f := fc.getDataFrame()
f.FrameHeader = fh
var padSize byte
if fh.Flags.Has(FlagDataPadded) {
var err error
payload, padSize, err = readByte(payload)
if err != nil {
countError("frame_data_pad_byte_short")
return nil, err
}
}
if int(padSize) > len(payload) {
// If the length of the padding is greater than the
// length of the frame payload, the recipient MUST
// treat this as a connection error.
// Filed: https://github.com/http2/http2-spec/issues/610
countError("frame_data_pad_too_big")
return nil, connError{ErrCodeProtocol, "pad size larger than data payload"}
}
f.data = payload[:len(payload)-int(padSize)]
return f, nil
}
var (
errStreamID = errors.New("invalid stream ID")
errDepStreamID = errors.New("invalid dependent stream ID")
errPadLength = errors.New("pad length too large")
errPadBytes = errors.New("padding bytes must all be zeros unless AllowIllegalWrites is enabled")
)
func validStreamIDOrZero(streamID uint32) bool {
return streamID&(1<<31) == 0
}
func validStreamID(streamID uint32) bool {
return streamID != 0 && streamID&(1<<31) == 0
}
// WriteData writes a DATA frame.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility not to violate the maximum frame size
// and to not call other Write methods concurrently.
func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error {
return f.WriteDataPadded(streamID, endStream, data, nil)
}
// WriteDataPadded writes a DATA frame with optional padding.
//
// If pad is nil, the padding bit is not sent.
// The length of pad must not exceed 255 bytes.
// The bytes of pad must all be zero, unless f.AllowIllegalWrites is set.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility not to violate the maximum frame size
// and to not call other Write methods concurrently.
func (f *Framer) WriteDataPadded(streamID uint32, endStream bool, data, pad []byte) error {
if !validStreamID(streamID) && !f.AllowIllegalWrites {
return errStreamID
}
if len(pad) > 0 {
if len(pad) > 255 {
return errPadLength
}
if !f.AllowIllegalWrites {
for _, b := range pad {
if b != 0 {
// "Padding octets MUST be set to zero when sending."
return errPadBytes
}
}
}
}
var flags Flags
if endStream {
flags |= FlagDataEndStream
}
if pad != nil {
flags |= FlagDataPadded
}
f.startWrite(FrameData, flags, streamID)
if pad != nil {
f.wbuf = append(f.wbuf, byte(len(pad)))
}
f.wbuf = append(f.wbuf, data...)
f.wbuf = append(f.wbuf, pad...)
return f.endWrite()
}
// A SettingsFrame conveys configuration parameters that affect how
// endpoints communicate, such as preferences and constraints on peer
// behavior.
//
// See http://http2.github.io/http2-spec/#SETTINGS
type SettingsFrame struct {
FrameHeader
p []byte
}
func parseSettingsFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
if fh.Flags.Has(FlagSettingsAck) && fh.Length > 0 {
// When this (ACK 0x1) bit is set, the payload of the
// SETTINGS frame MUST be empty. Receipt of a
// SETTINGS frame with the ACK flag set and a length
// field value other than 0 MUST be treated as a
// connection error (Section 5.4.1) of type
// FRAME_SIZE_ERROR.
countError("frame_settings_ack_with_length")
return nil, ConnectionError(ErrCodeFrameSize)
}
if fh.StreamID != 0 {
// SETTINGS frames always apply to a connection,
// never a single stream. The stream identifier for a
// SETTINGS frame MUST be zero (0x0). If an endpoint
// receives a SETTINGS frame whose stream identifier
// field is anything other than 0x0, the endpoint MUST
// respond with a connection error (Section 5.4.1) of
// type PROTOCOL_ERROR.
countError("frame_settings_has_stream")
return nil, ConnectionError(ErrCodeProtocol)
}
if len(p)%6 != 0 {
countError("frame_settings_mod_6")
// Expecting even number of 6 byte settings.
return nil, ConnectionError(ErrCodeFrameSize)
}
f := &SettingsFrame{FrameHeader: fh, p: p}
if v, ok := f.Value(SettingInitialWindowSize); ok && v > (1<<31)-1 {
countError("frame_settings_window_size_too_big")
// Values above the maximum flow control window size of 2^31 - 1 MUST
// be treated as a connection error (Section 5.4.1) of type
// FLOW_CONTROL_ERROR.
return nil, ConnectionError(ErrCodeFlowControl)
}
return f, nil
}
func (f *SettingsFrame) IsAck() bool {
return f.FrameHeader.Flags.Has(FlagSettingsAck)
}
func (f *SettingsFrame) Value(id SettingID) (v uint32, ok bool) {
f.checkValid()
for i := 0; i < f.NumSettings(); i++ {
if s := f.Setting(i); s.ID == id {
return s.Val, true
}
}
return 0, false
}
// Setting returns the setting from the frame at the given 0-based index.
// The index must be >= 0 and less than f.NumSettings().
func (f *SettingsFrame) Setting(i int) Setting {
buf := f.p
return Setting{
ID: SettingID(binary.BigEndian.Uint16(buf[i*6 : i*6+2])),
Val: binary.BigEndian.Uint32(buf[i*6+2 : i*6+6]),
}
}
func (f *SettingsFrame) NumSettings() int { return len(f.p) / 6 }
// HasDuplicates reports whether f contains any duplicate setting IDs.
func (f *SettingsFrame) HasDuplicates() bool {
num := f.NumSettings()
if num == 0 {
return false
}
// If it's small enough (the common case), just do the n^2
// thing and avoid a map allocation.
if num < 10 {
for i := 0; i < num; i++ {
idi := f.Setting(i).ID
for j := i + 1; j < num; j++ {
idj := f.Setting(j).ID
if idi == idj {
return true
}
}
}
return false
}
seen := map[SettingID]bool{}
for i := 0; i < num; i++ {
id := f.Setting(i).ID
if seen[id] {
return true
}
seen[id] = true
}
return false
}
// ForeachSetting runs fn for each setting.
// It stops and returns the first error.
func (f *SettingsFrame) ForeachSetting(fn func(Setting) error) error {
f.checkValid()
for i := 0; i < f.NumSettings(); i++ {
if err := fn(f.Setting(i)); err != nil {
return err
}
}
return nil
}
// WriteSettings writes a SETTINGS frame with zero or more settings
// specified and the ACK bit not set.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WriteSettings(settings ...Setting) error {
f.startWrite(FrameSettings, 0, 0)
for _, s := range settings {
f.writeUint16(uint16(s.ID))
f.writeUint32(s.Val)
}
return f.endWrite()
}
// WriteSettingsAck writes an empty SETTINGS frame with the ACK bit set.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WriteSettingsAck() error {
f.startWrite(FrameSettings, FlagSettingsAck, 0)
return f.endWrite()
}
// A PingFrame is a mechanism for measuring a minimal round trip time
// from the sender, as well as determining whether an idle connection
// is still functional.
// See http://http2.github.io/http2-spec/#rfc.section.6.7
type PingFrame struct {
FrameHeader
Data [8]byte
}
func (f *PingFrame) IsAck() bool { return f.Flags.Has(FlagPingAck) }
func parsePingFrame(_ *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
if len(payload) != 8 {
countError("frame_ping_length")
return nil, ConnectionError(ErrCodeFrameSize)
}
if fh.StreamID != 0 {
countError("frame_ping_has_stream")
return nil, ConnectionError(ErrCodeProtocol)
}
f := &PingFrame{FrameHeader: fh}
copy(f.Data[:], payload)
return f, nil
}
func (f *Framer) WritePing(ack bool, data [8]byte) error {
var flags Flags
if ack {
flags = FlagPingAck
}
f.startWrite(FramePing, flags, 0)
f.writeBytes(data[:])
return f.endWrite()
}
// A GoAwayFrame informs the remote peer to stop creating streams on this connection.
// See http://http2.github.io/http2-spec/#rfc.section.6.8
type GoAwayFrame struct {
FrameHeader
LastStreamID uint32
ErrCode ErrCode
debugData []byte
}
// DebugData returns any debug data in the GOAWAY frame. Its contents
// are not defined.
// The caller must not retain the returned memory past the next
// call to ReadFrame.
func (f *GoAwayFrame) DebugData() []byte {
f.checkValid()
return f.debugData
}
func parseGoAwayFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
if fh.StreamID != 0 {
countError("frame_goaway_has_stream")
return nil, ConnectionError(ErrCodeProtocol)
}
if len(p) < 8 {
countError("frame_goaway_short")
return nil, ConnectionError(ErrCodeFrameSize)
}
return &GoAwayFrame{
FrameHeader: fh,
LastStreamID: binary.BigEndian.Uint32(p[:4]) & (1<<31 - 1),
ErrCode: ErrCode(binary.BigEndian.Uint32(p[4:8])),
debugData: p[8:],
}, nil
}
func (f *Framer) WriteGoAway(maxStreamID uint32, code ErrCode, debugData []byte) error {
f.startWrite(FrameGoAway, 0, 0)
f.writeUint32(maxStreamID & (1<<31 - 1))
f.writeUint32(uint32(code))
f.writeBytes(debugData)
return f.endWrite()
}
// An UnknownFrame is the frame type returned when the frame type is unknown
// or no specific frame type parser exists.
type UnknownFrame struct {
FrameHeader
p []byte
}
// Payload returns the frame's payload (after the header). It is not
// valid to call this method after a subsequent call to
// Framer.ReadFrame, nor is it valid to retain the returned slice.
// The memory is owned by the Framer and is invalidated when the next
// frame is read.
func (f *UnknownFrame) Payload() []byte {
f.checkValid()
return f.p
}
func parseUnknownFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
return &UnknownFrame{fh, p}, nil
}
// A WindowUpdateFrame is used to implement flow control.
// See http://http2.github.io/http2-spec/#rfc.section.6.9
type WindowUpdateFrame struct {
FrameHeader
Increment uint32 // never read with high bit set
}
func parseWindowUpdateFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
if len(p) != 4 {
countError("frame_windowupdate_bad_len")
return nil, ConnectionError(ErrCodeFrameSize)
}
inc := binary.BigEndian.Uint32(p[:4]) & 0x7fffffff // mask off high reserved bit
if inc == 0 {
// A receiver MUST treat the receipt of a
// WINDOW_UPDATE frame with an flow control window
// increment of 0 as a stream error (Section 5.4.2) of
// type PROTOCOL_ERROR; errors on the connection flow
// control window MUST be treated as a connection
// error (Section 5.4.1).
if fh.StreamID == 0 {
countError("frame_windowupdate_zero_inc_conn")
return nil, ConnectionError(ErrCodeProtocol)
}
countError("frame_windowupdate_zero_inc_stream")
return nil, streamError(fh.StreamID, ErrCodeProtocol)
}
return &WindowUpdateFrame{
FrameHeader: fh,
Increment: inc,
}, nil
}
// WriteWindowUpdate writes a WINDOW_UPDATE frame.
// The increment value must be between 1 and 2,147,483,647, inclusive.
// If the Stream ID is zero, the window update applies to the
// connection as a whole.
func (f *Framer) WriteWindowUpdate(streamID, incr uint32) error {
// "The legal range for the increment to the flow control window is 1 to 2^31-1 (2,147,483,647) octets."
if (incr < 1 || incr > 2147483647) && !f.AllowIllegalWrites {
return errors.New("illegal window increment value")
}
f.startWrite(FrameWindowUpdate, 0, streamID)
f.writeUint32(incr)
return f.endWrite()
}
// A HeadersFrame is used to open a stream and additionally carries a
// header block fragment.
type HeadersFrame struct {
FrameHeader
// Priority is set if FlagHeadersPriority is set in the FrameHeader.
Priority PriorityParam
headerFragBuf []byte // not owned
}
func (f *HeadersFrame) HeaderBlockFragment() []byte {
f.checkValid()
return f.headerFragBuf
}
func (f *HeadersFrame) HeadersEnded() bool {
return f.FrameHeader.Flags.Has(FlagHeadersEndHeaders)
}
func (f *HeadersFrame) StreamEnded() bool {
return f.FrameHeader.Flags.Has(FlagHeadersEndStream)
}
func (f *HeadersFrame) HasPriority() bool {
return f.FrameHeader.Flags.Has(FlagHeadersPriority)
}
func parseHeadersFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (_ Frame, err error) {
hf := &HeadersFrame{
FrameHeader: fh,
}
if fh.StreamID == 0 {
// HEADERS frames MUST be associated with a stream. If a HEADERS frame
// is received whose stream identifier field is 0x0, the recipient MUST
// respond with a connection error (Section 5.4.1) of type
// PROTOCOL_ERROR.
countError("frame_headers_zero_stream")
return nil, connError{ErrCodeProtocol, "HEADERS frame with stream ID 0"}
}
var padLength uint8
if fh.Flags.Has(FlagHeadersPadded) {
if p, padLength, err = readByte(p); err != nil {
countError("frame_headers_pad_short")
return
}
}
if fh.Flags.Has(FlagHeadersPriority) {
var v uint32
p, v, err = readUint32(p)
if err != nil {
countError("frame_headers_prio_short")
return nil, err
}
hf.Priority.StreamDep = v & 0x7fffffff
hf.Priority.Exclusive = (v != hf.Priority.StreamDep) // high bit was set
p, hf.Priority.Weight, err = readByte(p)
if err != nil {
countError("frame_headers_prio_weight_short")
return nil, err
}
}
if len(p)-int(padLength) < 0 {
countError("frame_headers_pad_too_big")
return nil, streamError(fh.StreamID, ErrCodeProtocol)
}
hf.headerFragBuf = p[:len(p)-int(padLength)]
return hf, nil
}
// HeadersFrameParam are the parameters for writing a HEADERS frame.
type HeadersFrameParam struct {
// StreamID is the required Stream ID to initiate.
StreamID uint32
// BlockFragment is part (or all) of a Header Block.
BlockFragment []byte
// EndStream indicates that the header block is the last that
// the endpoint will send for the identified stream. Setting
// this flag causes the stream to enter one of "half closed"
// states.
EndStream bool
// EndHeaders indicates that this frame contains an entire
// header block and is not followed by any
// CONTINUATION frames.
EndHeaders bool
// PadLength is the optional number of bytes of zeros to add
// to this frame.
PadLength uint8
// Priority, if non-zero, includes stream priority information
// in the HEADER frame.
Priority PriorityParam
}
// WriteHeaders writes a single HEADERS frame.
//
// This is a low-level header writing method. Encoding headers and
// splitting them into any necessary CONTINUATION frames is handled
// elsewhere.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WriteHeaders(p HeadersFrameParam) error {
if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
return errStreamID
}
var flags Flags
if p.PadLength != 0 {
flags |= FlagHeadersPadded
}
if p.EndStream {
flags |= FlagHeadersEndStream
}
if p.EndHeaders {
flags |= FlagHeadersEndHeaders
}
if !p.Priority.IsZero() {
flags |= FlagHeadersPriority
}
f.startWrite(FrameHeaders, flags, p.StreamID)
if p.PadLength != 0 {
f.writeByte(p.PadLength)
}
if !p.Priority.IsZero() {
v := p.Priority.StreamDep
if !validStreamIDOrZero(v) && !f.AllowIllegalWrites {
return errDepStreamID
}
if p.Priority.Exclusive {
v |= 1 << 31
}
f.writeUint32(v)
f.writeByte(p.Priority.Weight)
}
f.wbuf = append(f.wbuf, p.BlockFragment...)
f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
return f.endWrite()
}
// A PriorityFrame specifies the sender-advised priority of a stream.
// See http://http2.github.io/http2-spec/#rfc.section.6.3
type PriorityFrame struct {
FrameHeader
PriorityParam
}
// PriorityParam are the stream prioritzation parameters.
type PriorityParam struct {
// StreamDep is a 31-bit stream identifier for the
// stream that this stream depends on. Zero means no
// dependency.
StreamDep uint32
// Exclusive is whether the dependency is exclusive.
Exclusive bool
// Weight is the stream's zero-indexed weight. It should be
// set together with StreamDep, or neither should be set. Per
// the spec, "Add one to the value to obtain a weight between
// 1 and 256."
Weight uint8
}
func (p PriorityParam) IsZero() bool {
return p == PriorityParam{}
}
func parsePriorityFrame(_ *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
if fh.StreamID == 0 {
countError("frame_priority_zero_stream")
return nil, connError{ErrCodeProtocol, "PRIORITY frame with stream ID 0"}
}
if len(payload) != 5 {
countError("frame_priority_bad_length")
return nil, connError{ErrCodeFrameSize, fmt.Sprintf("PRIORITY frame payload size was %d; want 5", len(payload))}
}
v := binary.BigEndian.Uint32(payload[:4])
streamID := v & 0x7fffffff // mask off high bit
return &PriorityFrame{
FrameHeader: fh,
PriorityParam: PriorityParam{
Weight: payload[4],
StreamDep: streamID,
Exclusive: streamID != v, // was high bit set?
},
}, nil
}
// WritePriority writes a PRIORITY frame.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WritePriority(streamID uint32, p PriorityParam) error {
if !validStreamID(streamID) && !f.AllowIllegalWrites {
return errStreamID
}
if !validStreamIDOrZero(p.StreamDep) {
return errDepStreamID
}
f.startWrite(FramePriority, 0, streamID)
v := p.StreamDep
if p.Exclusive {
v |= 1 << 31
}
f.writeUint32(v)
f.writeByte(p.Weight)
return f.endWrite()
}
// A RSTStreamFrame allows for abnormal termination of a stream.
// See http://http2.github.io/http2-spec/#rfc.section.6.4
type RSTStreamFrame struct {
FrameHeader
ErrCode ErrCode
}
func parseRSTStreamFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
if len(p) != 4 {
countError("frame_rststream_bad_len")
return nil, ConnectionError(ErrCodeFrameSize)
}
if fh.StreamID == 0 {
countError("frame_rststream_zero_stream")
return nil, ConnectionError(ErrCodeProtocol)
}
return &RSTStreamFrame{fh, ErrCode(binary.BigEndian.Uint32(p[:4]))}, nil
}
// WriteRSTStream writes a RST_STREAM frame.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WriteRSTStream(streamID uint32, code ErrCode) error {
if !validStreamID(streamID) && !f.AllowIllegalWrites {
return errStreamID
}
f.startWrite(FrameRSTStream, 0, streamID)
f.writeUint32(uint32(code))
return f.endWrite()
}
// A ContinuationFrame is used to continue a sequence of header block fragments.
// See http://http2.github.io/http2-spec/#rfc.section.6.10
type ContinuationFrame struct {
FrameHeader
headerFragBuf []byte
}
func parseContinuationFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
if fh.StreamID == 0 {
countError("frame_continuation_zero_stream")
return nil, connError{ErrCodeProtocol, "CONTINUATION frame with stream ID 0"}
}
return &ContinuationFrame{fh, p}, nil
}
func (f *ContinuationFrame) HeaderBlockFragment() []byte {
f.checkValid()
return f.headerFragBuf
}
func (f *ContinuationFrame) HeadersEnded() bool {
return f.FrameHeader.Flags.Has(FlagContinuationEndHeaders)
}
// WriteContinuation writes a CONTINUATION frame.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WriteContinuation(streamID uint32, endHeaders bool, headerBlockFragment []byte) error {
if !validStreamID(streamID) && !f.AllowIllegalWrites {
return errStreamID
}
var flags Flags
if endHeaders {
flags |= FlagContinuationEndHeaders
}
f.startWrite(FrameContinuation, flags, streamID)
f.wbuf = append(f.wbuf, headerBlockFragment...)
return f.endWrite()
}
// A PushPromiseFrame is used to initiate a server stream.
// See http://http2.github.io/http2-spec/#rfc.section.6.6
type PushPromiseFrame struct {
FrameHeader
PromiseID uint32
headerFragBuf []byte // not owned
}
func (f *PushPromiseFrame) HeaderBlockFragment() []byte {
f.checkValid()
return f.headerFragBuf
}
func (f *PushPromiseFrame) HeadersEnded() bool {
return f.FrameHeader.Flags.Has(FlagPushPromiseEndHeaders)
}
func parsePushPromise(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (_ Frame, err error) {
pp := &PushPromiseFrame{
FrameHeader: fh,
}
if pp.StreamID == 0 {
// PUSH_PROMISE frames MUST be associated with an existing,
// peer-initiated stream. The stream identifier of a
// PUSH_PROMISE frame indicates the stream it is associated
// with. If the stream identifier field specifies the value
// 0x0, a recipient MUST respond with a connection error
// (Section 5.4.1) of type PROTOCOL_ERROR.
countError("frame_pushpromise_zero_stream")
return nil, ConnectionError(ErrCodeProtocol)
}
// The PUSH_PROMISE frame includes optional padding.
// Padding fields and flags are identical to those defined for DATA frames
var padLength uint8
if fh.Flags.Has(FlagPushPromisePadded) {
if p, padLength, err = readByte(p); err != nil {
countError("frame_pushpromise_pad_short")
return
}
}
p, pp.PromiseID, err = readUint32(p)
if err != nil {
countError("frame_pushpromise_promiseid_short")
return
}
pp.PromiseID = pp.PromiseID & (1<<31 - 1)
if int(padLength) > len(p) {
// like the DATA frame, error out if padding is longer than the body.
countError("frame_pushpromise_pad_too_big")
return nil, ConnectionError(ErrCodeProtocol)
}
pp.headerFragBuf = p[:len(p)-int(padLength)]
return pp, nil
}
// PushPromiseParam are the parameters for writing a PUSH_PROMISE frame.
type PushPromiseParam struct {
// StreamID is the required Stream ID to initiate.
StreamID uint32
// PromiseID is the required Stream ID which this
// Push Promises
PromiseID uint32
// BlockFragment is part (or all) of a Header Block.
BlockFragment []byte
// EndHeaders indicates that this frame contains an entire
// header block and is not followed by any
// CONTINUATION frames.
EndHeaders bool
// PadLength is the optional number of bytes of zeros to add
// to this frame.
PadLength uint8
}
// WritePushPromise writes a single PushPromise Frame.
//
// As with Header Frames, This is the low level call for writing
// individual frames. Continuation frames are handled elsewhere.
//
// It will perform exactly one Write to the underlying Writer.
// It is the caller's responsibility to not call other Write methods concurrently.
func (f *Framer) WritePushPromise(p PushPromiseParam) error {
if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
return errStreamID
}
var flags Flags
if p.PadLength != 0 {
flags |= FlagPushPromisePadded
}
if p.EndHeaders {
flags |= FlagPushPromiseEndHeaders
}
f.startWrite(FramePushPromise, flags, p.StreamID)
if p.PadLength != 0 {
f.writeByte(p.PadLength)
}
if !validStreamID(p.PromiseID) && !f.AllowIllegalWrites {
return errStreamID
}
f.writeUint32(p.PromiseID)
f.wbuf = append(f.wbuf, p.BlockFragment...)
f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
return f.endWrite()
}
// WriteRawFrame writes a raw frame. This can be used to write
// extension frames unknown to this package.
func (f *Framer) WriteRawFrame(t FrameType, flags Flags, streamID uint32, payload []byte) error {
f.startWrite(t, flags, streamID)
f.writeBytes(payload)
return f.endWrite()
}
func readByte(p []byte) (remain []byte, b byte, err error) {
if len(p) == 0 {
return nil, 0, io.ErrUnexpectedEOF
}
return p[1:], p[0], nil
}
func readUint32(p []byte) (remain []byte, v uint32, err error) {
if len(p) < 4 {
return nil, 0, io.ErrUnexpectedEOF
}
return p[4:], binary.BigEndian.Uint32(p[:4]), nil
}
type streamEnder interface {
StreamEnded() bool
}
type headersEnder interface {
HeadersEnded() bool
}
type headersOrContinuation interface {
headersEnder
HeaderBlockFragment() []byte
}
// A MetaHeadersFrame is the representation of one HEADERS frame and
// zero or more contiguous CONTINUATION frames and the decoding of
// their HPACK-encoded contents.
//
// This type of frame does not appear on the wire and is only returned
// by the Framer when Framer.ReadMetaHeaders is set.
type MetaHeadersFrame struct {
*HeadersFrame
// Fields are the fields contained in the HEADERS and
// CONTINUATION frames. The underlying slice is owned by the
// Framer and must not be retained after the next call to
// ReadFrame.
//
// Fields are guaranteed to be in the correct http2 order and
// not have unknown pseudo header fields or invalid header
// field names or values. Required pseudo header fields may be
// missing, however. Use the MetaHeadersFrame.Pseudo accessor
// method access pseudo headers.
Fields []hpack.HeaderField
// Truncated is whether the max header list size limit was hit
// and Fields is incomplete. The hpack decoder state is still
// valid, however.
Truncated bool
}
// PseudoValue returns the given pseudo header field's value.
// The provided pseudo field should not contain the leading colon.
func (mh *MetaHeadersFrame) PseudoValue(pseudo string) string {
for _, hf := range mh.Fields {
if !hf.IsPseudo() {
return ""
}
if hf.Name[1:] == pseudo {
return hf.Value
}
}
return ""
}
// RegularFields returns the regular (non-pseudo) header fields of mh.
// The caller does not own the returned slice.
func (mh *MetaHeadersFrame) RegularFields() []hpack.HeaderField {
for i, hf := range mh.Fields {
if !hf.IsPseudo() {
return mh.Fields[i:]
}
}
return nil
}
// PseudoFields returns the pseudo header fields of mh.
// The caller does not own the returned slice.
func (mh *MetaHeadersFrame) PseudoFields() []hpack.HeaderField {
for i, hf := range mh.Fields {
if !hf.IsPseudo() {
return mh.Fields[:i]
}
}
return mh.Fields
}
func (mh *MetaHeadersFrame) checkPseudos() error {
var isRequest, isResponse bool
pf := mh.PseudoFields()
for i, hf := range pf {
switch hf.Name {
case ":method", ":path", ":scheme", ":authority":
isRequest = true
case ":status":
isResponse = true
default:
return pseudoHeaderError(hf.Name)
}
// Check for duplicates.
// This would be a bad algorithm, but N is 4.
// And this doesn't allocate.
for _, hf2 := range pf[:i] {
if hf.Name == hf2.Name {
return duplicatePseudoHeaderError(hf.Name)
}
}
}
if isRequest && isResponse {
return errMixPseudoHeaderTypes
}
return nil
}
func (fr *Framer) maxHeaderStringLen() int {
v := fr.maxHeaderListSize()
if uint32(int(v)) == v {
return int(v)
}
// They had a crazy big number for MaxHeaderBytes anyway,
// so give them unlimited header lengths:
return 0
}
// readMetaFrame returns 0 or more CONTINUATION frames from fr and
// merge them into the provided hf and returns a MetaHeadersFrame
// with the decoded hpack values.
func (fr *Framer) readMetaFrame(hf *HeadersFrame) (*MetaHeadersFrame, error) {
if fr.AllowIllegalReads {
return nil, errors.New("illegal use of AllowIllegalReads with ReadMetaHeaders")
}
mh := &MetaHeadersFrame{
HeadersFrame: hf,
}
var remainSize = fr.maxHeaderListSize()
var sawRegular bool
var invalid error // pseudo header field errors
hdec := fr.ReadMetaHeaders
hdec.SetEmitEnabled(true)
hdec.SetMaxStringLength(fr.maxHeaderStringLen())
hdec.SetEmitFunc(func(hf hpack.HeaderField) {
if VerboseLogs && fr.logReads {
fr.debugReadLoggerf("http2: decoded hpack field %+v", hf)
}
if !httpguts.ValidHeaderFieldValue(hf.Value) {
// Don't include the value in the error, because it may be sensitive.
invalid = headerFieldValueError(hf.Name)
}
isPseudo := strings.HasPrefix(hf.Name, ":")
if isPseudo {
if sawRegular {
invalid = errPseudoAfterRegular
}
} else {
sawRegular = true
if !validWireHeaderFieldName(hf.Name) {
invalid = headerFieldNameError(hf.Name)
}
}
if invalid != nil {
hdec.SetEmitEnabled(false)
return
}
size := hf.Size()
if size > remainSize {
hdec.SetEmitEnabled(false)
mh.Truncated = true
return
}
remainSize -= size
mh.Fields = append(mh.Fields, hf)
})
// Lose reference to MetaHeadersFrame:
defer hdec.SetEmitFunc(func(hf hpack.HeaderField) {})
var hc headersOrContinuation = hf
for {
frag := hc.HeaderBlockFragment()
if _, err := hdec.Write(frag); err != nil {
return nil, ConnectionError(ErrCodeCompression)
}
if hc.HeadersEnded() {
break
}
if f, err := fr.ReadFrame(); err != nil {
return nil, err
} else {
hc = f.(*ContinuationFrame) // guaranteed by checkFrameOrder
}
}
mh.HeadersFrame.headerFragBuf = nil
mh.HeadersFrame.invalidate()
if err := hdec.Close(); err != nil {
return nil, ConnectionError(ErrCodeCompression)
}
if invalid != nil {
fr.errDetail = invalid
if VerboseLogs {
log.Printf("http2: invalid header: %v", invalid)
}
return nil, StreamError{mh.StreamID, ErrCodeProtocol, invalid}
}
if err := mh.checkPseudos(); err != nil {
fr.errDetail = err
if VerboseLogs {
log.Printf("http2: invalid pseudo headers: %v", err)
}
return nil, StreamError{mh.StreamID, ErrCodeProtocol, err}
}
return mh, nil
}
func summarizeFrame(f Frame) string {
var buf bytes.Buffer
f.Header().writeDebug(&buf)
switch f := f.(type) {
case *SettingsFrame:
n := 0
f.ForeachSetting(func(s Setting) error {
n++
if n == 1 {
buf.WriteString(", settings:")
}
fmt.Fprintf(&buf, " %v=%v,", s.ID, s.Val)
return nil
})
if n > 0 {
buf.Truncate(buf.Len() - 1) // remove trailing comma
}
case *DataFrame:
data := f.Data()
const max = 256
if len(data) > max {
data = data[:max]
}
fmt.Fprintf(&buf, " data=%q", data)
if len(f.Data()) > max {
fmt.Fprintf(&buf, " (%d bytes omitted)", len(f.Data())-max)
}
case *WindowUpdateFrame:
if f.StreamID == 0 {
buf.WriteString(" (conn)")
}
fmt.Fprintf(&buf, " incr=%v", f.Increment)
case *PingFrame:
fmt.Fprintf(&buf, " ping=%q", f.Data[:])
case *GoAwayFrame:
fmt.Fprintf(&buf, " LastStreamID=%v ErrCode=%v Debug=%q",
f.LastStreamID, f.ErrCode, f.debugData)
case *RSTStreamFrame:
fmt.Fprintf(&buf, " ErrCode=%v", f.ErrCode)
}
return buf.String()
}
