forked from quic-go/quic-go
87 lines
1.7 KiB
Go
87 lines
1.7 KiB
Go
package quic
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import (
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"bytes"
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"io/ioutil"
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)
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// A StreamFrame of QUIC
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// TODO: Maybe remove unneeded stuff, e.g. lengths?
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type StreamFrame struct {
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FinBit bool
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StreamID uint32
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Offset uint64
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Data []byte
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}
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// ParseStreamFrame reads a stream frame. The type byte must not have been read yet.
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func ParseStreamFrame(r *bytes.Reader) (*StreamFrame, error) {
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frame := &StreamFrame{}
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typeByte, err := r.ReadByte()
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if err != nil {
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return nil, err
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}
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frame.FinBit = typeByte&0x40 > 0
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dataLenPresent := typeByte&0x20 > 0
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offsetLen := typeByte & 0x1C >> 2
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if offsetLen != 0 {
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offsetLen++
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}
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streamIDLen := typeByte&0x03 + 1
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sid, err := readUintN(r, streamIDLen)
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if err != nil {
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return nil, err
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}
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frame.StreamID = uint32(sid)
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frame.Offset, err = readUintN(r, offsetLen)
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if err != nil {
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return nil, err
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}
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var dataLen uint16
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if dataLenPresent {
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dataLen, err = readUint16(r)
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if err != nil {
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return nil, err
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}
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}
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if dataLen == 0 {
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// The rest of the packet is data
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frame.Data, err = ioutil.ReadAll(r)
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if err != nil {
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return nil, err
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}
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} else {
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frame.Data = make([]byte, dataLen)
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if _, err := r.Read(frame.Data); err != nil {
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return nil, err
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}
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}
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return frame, nil
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}
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// WriteStreamFrame writes a stream frame.
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func WriteStreamFrame(b *bytes.Buffer, f *StreamFrame) {
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typeByte := uint8(0x80)
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if f.FinBit {
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typeByte ^= 0x40
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}
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typeByte ^= 0x20
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if f.Offset != 0 {
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typeByte ^= 0x1c // TODO: Send shorter offset if possible
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}
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typeByte ^= 0x03 // TODO: Send shorter stream ID if possible
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b.WriteByte(typeByte)
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writeUint32(b, f.StreamID)
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if f.Offset != 0 {
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writeUint64(b, f.Offset)
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}
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writeUint16(b, uint16(len(f.Data)))
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b.Write(f.Data)
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}
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