package quic import ( "fmt" "io" "github.com/lucas-clemente/quic-go/internal/protocol" "github.com/lucas-clemente/quic-go/internal/qerr" "github.com/lucas-clemente/quic-go/internal/utils" "github.com/lucas-clemente/quic-go/internal/wire" ) type cryptoStream interface { // for receiving data HandleCryptoFrame(*wire.CryptoFrame) error GetCryptoData() []byte Finish() error // for sending data io.Writer HasData() bool PopCryptoFrame(protocol.ByteCount) *wire.CryptoFrame } type cryptoStreamImpl struct { queue *frameSorter msgBuf []byte highestOffset protocol.ByteCount finished bool writeOffset protocol.ByteCount writeBuf []byte } func newCryptoStream() cryptoStream { return &cryptoStreamImpl{queue: newFrameSorter()} } func (s *cryptoStreamImpl) HandleCryptoFrame(f *wire.CryptoFrame) error { highestOffset := f.Offset + protocol.ByteCount(len(f.Data)) if maxOffset := highestOffset; maxOffset > protocol.MaxCryptoStreamOffset { return &qerr.TransportError{ ErrorCode: qerr.CryptoBufferExceeded, ErrorMessage: fmt.Sprintf("received invalid offset %d on crypto stream, maximum allowed %d", maxOffset, protocol.MaxCryptoStreamOffset), } } if s.finished { if highestOffset > s.highestOffset { // reject crypto data received after this stream was already finished return &qerr.TransportError{ ErrorCode: qerr.ProtocolViolation, ErrorMessage: "received crypto data after change of encryption level", } } // ignore data with a smaller offset than the highest received // could e.g. be a retransmission return nil } s.highestOffset = utils.Max(s.highestOffset, highestOffset) if err := s.queue.Push(f.Data, f.Offset, nil); err != nil { return err } for { _, data, _ := s.queue.Pop() if data == nil { return nil } s.msgBuf = append(s.msgBuf, data...) } } // GetCryptoData retrieves data that was received in CRYPTO frames func (s *cryptoStreamImpl) GetCryptoData() []byte { if len(s.msgBuf) < 4 { return nil } msgLen := 4 + int(s.msgBuf[1])<<16 + int(s.msgBuf[2])<<8 + int(s.msgBuf[3]) if len(s.msgBuf) < msgLen { return nil } msg := make([]byte, msgLen) copy(msg, s.msgBuf[:msgLen]) s.msgBuf = s.msgBuf[msgLen:] return msg } func (s *cryptoStreamImpl) Finish() error { if s.queue.HasMoreData() { return &qerr.TransportError{ ErrorCode: qerr.ProtocolViolation, ErrorMessage: "encryption level changed, but crypto stream has more data to read", } } s.finished = true return nil } // Writes writes data that should be sent out in CRYPTO frames func (s *cryptoStreamImpl) Write(p []byte) (int, error) { s.writeBuf = append(s.writeBuf, p...) return len(p), nil } func (s *cryptoStreamImpl) HasData() bool { return len(s.writeBuf) > 0 } func (s *cryptoStreamImpl) PopCryptoFrame(maxLen protocol.ByteCount) *wire.CryptoFrame { f := &wire.CryptoFrame{Offset: s.writeOffset} n := utils.Min(f.MaxDataLen(maxLen), protocol.ByteCount(len(s.writeBuf))) f.Data = s.writeBuf[:n] s.writeBuf = s.writeBuf[n:] s.writeOffset += n return f }