/usr/share/gocode/src/github.com/bradfitz/http2/frame.go is in golang-github-bradfitz-http2-dev 0.0~git20150509-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// See https://code.google.com/p/go/source/browse/CONTRIBUTORS
// Licensed under the same terms as Go itself:
// https://code.google.com/p/go/source/browse/LICENSE
package http2
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"sync"
)
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(fh FrameHeader, 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 ")
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<<i) == 0 {
continue
}
set++
if set > 1 {
buf.WriteByte('|')
}
name := flagName[h.Type][Flags(1<<i)]
if name != "" {
buf.WriteString(name)
} else {
fmt.Fprintf(&buf, "0x%x", 1<<i)
}
}
}
if h.StreamID != 0 {
fmt.Fprintf(&buf, " stream=%d", h.StreamID)
}
fmt.Fprintf(&buf, " len=%d]", h.Length)
return buf.String()
}
func (h *FrameHeader) checkValid() {
if !h.valid {
panic("Frame accessor called on non-owned Frame")
}
}
func (h *FrameHeader) invalidate() { h.valid = false }
// frame header bytes.
// Used only by ReadFrameHeader.
var fhBytes = sync.Pool{
New: func() interface{} {
buf := make([]byte, frameHeaderLen)
return &buf
},
}
// ReadFrameHeader reads 9 bytes from r and returns a FrameHeader.
// Most users should use Framer.ReadFrame instead.
func ReadFrameHeader(r io.Reader) (FrameHeader, error) {
bufp := fhBytes.Get().(*[]byte)
defer fhBytes.Put(bufp)
return readFrameHeader(*bufp, r)
}
func readFrameHeader(buf []byte, r io.Reader) (FrameHeader, error) {
_, err := io.ReadFull(r, buf[:frameHeaderLen])
if err != nil {
return FrameHeader{}, err
}
return FrameHeader{
Length: (uint32(buf[0])<<16 | uint32(buf[1])<<8 | uint32(buf[2])),
Type: FrameType(buf[3]),
Flags: Flags(buf[4]),
StreamID: binary.BigEndian.Uint32(buf[5:]) & (1<<31 - 1),
valid: true,
}, nil
}
// A Frame is the base interface implemented by all frame types.
// Callers will generally type-assert the specific frame type:
// *HeadersFrame, *SettingsFrame, *WindowUpdateFrame, etc.
//
// Frames are only valid until the next call to Framer.ReadFrame.
type Frame interface {
Header() FrameHeader
// invalidate is called by Framer.ReadFrame to make this
// frame's buffers as being invalid, since the subsequent
// frame will reuse them.
invalidate()
}
// A Framer reads and writes Frames.
type Framer struct {
r io.Reader
lastFrame Frame
maxReadSize uint32
headerBuf [frameHeaderLen]byte
// TODO: let getReadBuf be configurable, and use a less memory-pinning
// allocator in server.go to minimize memory pinned for many idle conns.
// Will probably also need to make frame invalidation have a hook too.
getReadBuf func(size uint32) []byte
readBuf []byte // cache for default getReadBuf
maxWriteSize uint32 // zero means unlimited; TODO: implement
w io.Writer
wbuf []byte
// AllowIllegalWrites permits the Framer's Write methods to
// write frames that do not conform to the HTTP/2 spec. This
// permits using the Framer to test other HTTP/2
// implementations' conformance to the spec.
// If false, the Write methods will prefer to return an error
// rather than comply.
AllowIllegalWrites bool
// TODO: track which type of frame & with which flags was sent
// last. Then return an error (unless AllowIllegalWrites) if
// we're in the middle of a header block and a
// non-Continuation or Continuation on a different stream is
// attempted to be written.
}
func (f *Framer) startWrite(ftype FrameType, flags Flags, streamID uint32) {
// Write the FrameHeader.
f.wbuf = append(f.wbuf[:0],
0, // 3 bytes of length, filled in in endWrite
0,
0,
byte(ftype),
byte(flags),
byte(streamID>>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))
n, err := f.w.Write(f.wbuf)
if err == nil && n != len(f.wbuf) {
err = io.ErrShortWrite
}
return err
}
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
)
// 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,
}
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
}
// 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")
// 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.
func (fr *Framer) ReadFrame() (Frame, error) {
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)(fh, payload)
if err != nil {
return nil, err
}
fr.lastFrame = f
return f, 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(fh FrameHeader, 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.
return nil, ConnectionError(ErrCodeProtocol)
}
f := &DataFrame{
FrameHeader: fh,
}
var padSize byte
if fh.Flags.Has(FlagDataPadded) {
var err error
payload, padSize, err = readByte(payload)
if err != nil {
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
return nil, ConnectionError(ErrCodeProtocol)
}
f.data = payload[:len(payload)-int(padSize)]
return f, nil
}
var errStreamID = errors.New("invalid streamid")
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 to not call other Write methods concurrently.
func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error {
// TODO: ignoring padding for now. will add when somebody cares.
if !validStreamID(streamID) && !f.AllowIllegalWrites {
return errStreamID
}
var flags Flags
if endStream {
flags |= FlagDataEndStream
}
f.startWrite(FrameData, flags, streamID)
f.wbuf = append(f.wbuf, data...)
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(fh FrameHeader, 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.
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.
return nil, ConnectionError(ErrCodeProtocol)
}
if len(p)%6 != 0 {
// 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 {
// 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(s SettingID) (v uint32, ok bool) {
f.checkValid()
buf := f.p
for len(buf) > 0 {
settingID := SettingID(binary.BigEndian.Uint16(buf[:2]))
if settingID == s {
return binary.BigEndian.Uint32(buf[2:6]), true
}
buf = buf[6:]
}
return 0, 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()
buf := f.p
for len(buf) > 0 {
if err := fn(Setting{
SettingID(binary.BigEndian.Uint16(buf[:2])),
binary.BigEndian.Uint32(buf[2:6]),
}); err != nil {
return err
}
buf = buf[6:]
}
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()
}
// WriteSettings 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 parsePingFrame(fh FrameHeader, payload []byte) (Frame, error) {
if len(payload) != 8 {
return nil, ConnectionError(ErrCodeFrameSize)
}
if fh.StreamID != 0 {
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(fh FrameHeader, p []byte) (Frame, error) {
if fh.StreamID != 0 {
return nil, ConnectionError(ErrCodeProtocol)
}
if len(p) < 8 {
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(fh FrameHeader, 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
}
func parseWindowUpdateFrame(fh FrameHeader, p []byte) (Frame, error) {
if len(p) != 4 {
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 {
return nil, ConnectionError(ErrCodeProtocol)
}
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(fh FrameHeader, 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.
return nil, ConnectionError(ErrCodeProtocol)
}
var padLength uint8
if fh.Flags.Has(FlagHeadersPadded) {
if p, padLength, err = readByte(p); err != nil {
return
}
}
if fh.Flags.Has(FlagHeadersPriority) {
var v uint32
p, v, err = readUint32(p)
if err != nil {
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 {
return nil, err
}
}
if len(p)-int(padLength) <= 0 {
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 !validStreamID(v) && !f.AllowIllegalWrites {
return errors.New("invalid dependent stream id")
}
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(fh FrameHeader, payload []byte) (Frame, error) {
if fh.StreamID == 0 {
return nil, ConnectionError(ErrCodeProtocol)
}
if len(payload) != 5 {
return nil, ConnectionError(ErrCodeFrameSize)
}
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
}
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(fh FrameHeader, p []byte) (Frame, error) {
if len(p) != 4 {
return nil, ConnectionError(ErrCodeFrameSize)
}
if fh.StreamID == 0 {
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(fh FrameHeader, p []byte) (Frame, error) {
return &ContinuationFrame{fh, p}, nil
}
func (f *ContinuationFrame) StreamEnded() bool {
return f.FrameHeader.Flags.Has(FlagDataEndStream)
}
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(fh FrameHeader, 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.
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 {
return
}
}
p, pp.PromiseID, err = readUint32(p)
if err != nil {
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.
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
}
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