136 lines
3.6 KiB
Go
136 lines
3.6 KiB
Go
package quic
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import (
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"errors"
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"fmt"
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"io"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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"github.com/lucas-clemente/quic-go/internal/utils"
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"github.com/lucas-clemente/quic-go/internal/wire"
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)
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type cryptoStream interface {
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// for receiving data
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HandleCryptoFrame(*wire.CryptoFrame) error
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GetCryptoData() []byte
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Finish() error
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// for sending data
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io.Writer
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HasData() bool
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PopCryptoFrame(protocol.ByteCount) *wire.CryptoFrame
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}
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type postHandshakeCryptoStream struct {
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cryptoStream
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framer framer
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}
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func newPostHandshakeCryptoStream(framer framer) cryptoStream {
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return &postHandshakeCryptoStream{
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cryptoStream: newCryptoStream(),
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framer: framer,
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}
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}
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// Write writes post-handshake messages.
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// For simplicity, post-handshake crypto messages are treated as control frames.
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// The framer functions as a stack (LIFO), so if there are multiple writes,
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// they will be returned in the opposite order.
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// This is acceptable, since post-handshake crypto messages are very rare.
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func (s *postHandshakeCryptoStream) Write(p []byte) (int, error) {
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n, err := s.cryptoStream.Write(p)
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if err != nil {
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return n, err
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}
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for s.cryptoStream.HasData() {
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s.framer.QueueControlFrame(s.PopCryptoFrame(protocol.MaxPostHandshakeCryptoFrameSize))
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}
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return n, nil
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}
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type cryptoStreamImpl struct {
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queue *frameSorter
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msgBuf []byte
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highestOffset protocol.ByteCount
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finished bool
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writeOffset protocol.ByteCount
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writeBuf []byte
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}
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func newCryptoStream() cryptoStream {
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return &cryptoStreamImpl{queue: newFrameSorter()}
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}
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func (s *cryptoStreamImpl) HandleCryptoFrame(f *wire.CryptoFrame) error {
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highestOffset := f.Offset + protocol.ByteCount(len(f.Data))
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if maxOffset := highestOffset; maxOffset > protocol.MaxCryptoStreamOffset {
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return fmt.Errorf("received invalid offset %d on crypto stream, maximum allowed %d", maxOffset, protocol.MaxCryptoStreamOffset)
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}
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if s.finished {
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if highestOffset > s.highestOffset {
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// reject crypto data received after this stream was already finished
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return errors.New("received crypto data after change of encryption level")
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}
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// ignore data with a smaller offset than the highest received
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// could e.g. be a retransmission
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return nil
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}
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s.highestOffset = utils.MaxByteCount(s.highestOffset, highestOffset)
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if err := s.queue.Push(f.Data, f.Offset); err != nil {
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return err
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}
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for {
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_, data := s.queue.Pop()
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if data == nil {
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return nil
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}
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s.msgBuf = append(s.msgBuf, data...)
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}
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}
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// GetCryptoData retrieves data that was received in CRYPTO frames
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func (s *cryptoStreamImpl) GetCryptoData() []byte {
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if len(s.msgBuf) < 4 {
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return nil
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}
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msgLen := 4 + int(s.msgBuf[1])<<16 + int(s.msgBuf[2])<<8 + int(s.msgBuf[3])
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if len(s.msgBuf) < msgLen {
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return nil
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}
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msg := make([]byte, msgLen)
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copy(msg, s.msgBuf[:msgLen])
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s.msgBuf = s.msgBuf[msgLen:]
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return msg
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}
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func (s *cryptoStreamImpl) Finish() error {
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if s.queue.HasMoreData() {
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return errors.New("encryption level changed, but crypto stream has more data to read")
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}
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s.finished = true
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return nil
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}
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// Writes writes data that should be sent out in CRYPTO frames
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func (s *cryptoStreamImpl) Write(p []byte) (int, error) {
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s.writeBuf = append(s.writeBuf, p...)
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return len(p), nil
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}
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func (s *cryptoStreamImpl) HasData() bool {
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return len(s.writeBuf) > 0
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}
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func (s *cryptoStreamImpl) PopCryptoFrame(maxLen protocol.ByteCount) *wire.CryptoFrame {
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f := &wire.CryptoFrame{Offset: s.writeOffset}
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n := utils.MinByteCount(f.MaxDataLen(maxLen), protocol.ByteCount(len(s.writeBuf)))
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f.Data = s.writeBuf[:n]
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s.writeBuf = s.writeBuf[n:]
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s.writeOffset += n
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return f
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}
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