forked from quic-go/quic-go
75 lines
1.8 KiB
Go
75 lines
1.8 KiB
Go
package http3
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import (
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"io"
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"github.com/quic-go/quic-go/quicvarint"
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)
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// CapsuleType is the type of the capsule
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type CapsuleType uint64
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// CapsuleProtocolHeader is the header value used to advertise support for the capsule protocol
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const CapsuleProtocolHeader = "Capsule-Protocol"
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type exactReader struct {
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R io.LimitedReader
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}
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func (r *exactReader) Read(b []byte) (int, error) {
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n, err := r.R.Read(b)
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if err == io.EOF && r.R.N > 0 {
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return n, io.ErrUnexpectedEOF
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}
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return n, err
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}
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type countingByteReader struct {
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io.ByteReader
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Read int
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}
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func (r *countingByteReader) ReadByte() (byte, error) {
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b, err := r.ByteReader.ReadByte()
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if err == nil {
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r.Read++
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}
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return b, err
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}
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// ParseCapsule parses the header of a Capsule.
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// It returns an io.Reader that can be used to read the Capsule value.
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// The Capsule value must be read entirely (i.e. until the io.EOF) before using r again.
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func ParseCapsule(r quicvarint.Reader) (CapsuleType, io.Reader, error) {
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cbr := countingByteReader{ByteReader: r}
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ct, err := quicvarint.Read(&cbr)
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if err != nil {
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// If an io.EOF is returned without consuming any bytes, return it unmodified.
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// Otherwise, return an io.ErrUnexpectedEOF.
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if err == io.EOF && cbr.Read > 0 {
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return 0, nil, io.ErrUnexpectedEOF
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}
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return 0, nil, err
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}
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l, err := quicvarint.Read(r)
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if err != nil {
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if err == io.EOF {
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return 0, nil, io.ErrUnexpectedEOF
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}
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return 0, nil, err
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}
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return CapsuleType(ct), &exactReader{R: io.LimitedReader{R: r, N: int64(l)}}, nil
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}
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// WriteCapsule writes a capsule
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func WriteCapsule(w quicvarint.Writer, ct CapsuleType, value []byte) error {
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b := make([]byte, 0, 16)
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b = quicvarint.Append(b, uint64(ct))
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b = quicvarint.Append(b, uint64(len(value)))
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if _, err := w.Write(b); err != nil {
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return err
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}
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_, err := w.Write(value)
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return err
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}
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