package crypto import ( "io" "v2ray.com/core/common" "v2ray.com/core/common/buf" "v2ray.com/core/common/serial" ) // ChunkSizeDecoder is a utility class to decode size value from bytes. type ChunkSizeDecoder interface { SizeBytes() int32 Decode([]byte) (uint16, error) } // ChunkSizeEncoder is a utility class to encode size value into bytes. type ChunkSizeEncoder interface { SizeBytes() int32 Encode(uint16, []byte) []byte } type PaddingLengthGenerator interface { MaxPaddingLen() uint16 NextPaddingLen() uint16 } type PlainChunkSizeParser struct{} func (PlainChunkSizeParser) SizeBytes() int32 { return 2 } func (PlainChunkSizeParser) Encode(size uint16, b []byte) []byte { return serial.Uint16ToBytes(size, b) } func (PlainChunkSizeParser) Decode(b []byte) (uint16, error) { return serial.BytesToUint16(b), nil } type AEADChunkSizeParser struct { Auth *AEADAuthenticator } func (p *AEADChunkSizeParser) SizeBytes() int32 { return 2 + int32(p.Auth.Overhead()) } func (p *AEADChunkSizeParser) Encode(size uint16, b []byte) []byte { b = serial.Uint16ToBytes(size-uint16(p.Auth.Overhead()), b) b, err := p.Auth.Seal(b[:0], b) common.Must(err) return b } func (p *AEADChunkSizeParser) Decode(b []byte) (uint16, error) { b, err := p.Auth.Open(b[:0], b) if err != nil { return 0, err } return serial.BytesToUint16(b) + uint16(p.Auth.Overhead()), nil } type ChunkStreamReader struct { sizeDecoder ChunkSizeDecoder reader *buf.BufferedReader buffer []byte leftOverSize int32 } func NewChunkStreamReader(sizeDecoder ChunkSizeDecoder, reader io.Reader) *ChunkStreamReader { return &ChunkStreamReader{ sizeDecoder: sizeDecoder, reader: &buf.BufferedReader{Reader: buf.NewReader(reader)}, buffer: make([]byte, sizeDecoder.SizeBytes()), } } func (r *ChunkStreamReader) readSize() (uint16, error) { if _, err := io.ReadFull(r.reader, r.buffer); err != nil { return 0, err } return r.sizeDecoder.Decode(r.buffer) } func (r *ChunkStreamReader) ReadMultiBuffer() (buf.MultiBuffer, error) { size := r.leftOverSize if size == 0 { nextSize, err := r.readSize() if err != nil { return nil, err } if nextSize == 0 { return nil, io.EOF } size = int32(nextSize) } r.leftOverSize = size mb, err := r.reader.ReadAtMost(size) if !mb.IsEmpty() { r.leftOverSize -= mb.Len() return mb, nil } return nil, err } type ChunkStreamWriter struct { sizeEncoder ChunkSizeEncoder writer buf.Writer } func NewChunkStreamWriter(sizeEncoder ChunkSizeEncoder, writer io.Writer) *ChunkStreamWriter { return &ChunkStreamWriter{ sizeEncoder: sizeEncoder, writer: buf.NewWriter(writer), } } func (w *ChunkStreamWriter) WriteMultiBuffer(mb buf.MultiBuffer) error { const sliceSize = 8192 mbLen := mb.Len() mb2Write := buf.NewMultiBufferCap(mbLen/buf.Size + mbLen/sliceSize + 2) for { slice := mb.SliceBySize(sliceSize) b := buf.New() common.Must(b.Reset(func(buffer []byte) (int, error) { w.sizeEncoder.Encode(uint16(slice.Len()), buffer[:0]) return int(w.sizeEncoder.SizeBytes()), nil })) mb2Write.Append(b) mb2Write.AppendMulti(slice) if mb.IsEmpty() { break } } return w.writer.WriteMultiBuffer(mb2Write) }