github.com/xmplusdev/xray-core@v1.8.10/common/crypto/chunk.go (about)

     1  package crypto
     2  
     3  import (
     4  	"encoding/binary"
     5  	"io"
     6  
     7  	"github.com/xmplusdev/xray-core/common"
     8  	"github.com/xmplusdev/xray-core/common/buf"
     9  )
    10  
    11  // ChunkSizeDecoder is a utility class to decode size value from bytes.
    12  type ChunkSizeDecoder interface {
    13  	SizeBytes() int32
    14  	Decode([]byte) (uint16, error)
    15  }
    16  
    17  // ChunkSizeEncoder is a utility class to encode size value into bytes.
    18  type ChunkSizeEncoder interface {
    19  	SizeBytes() int32
    20  	Encode(uint16, []byte) []byte
    21  }
    22  
    23  type PaddingLengthGenerator interface {
    24  	MaxPaddingLen() uint16
    25  	NextPaddingLen() uint16
    26  }
    27  
    28  type PlainChunkSizeParser struct{}
    29  
    30  func (PlainChunkSizeParser) SizeBytes() int32 {
    31  	return 2
    32  }
    33  
    34  func (PlainChunkSizeParser) Encode(size uint16, b []byte) []byte {
    35  	binary.BigEndian.PutUint16(b, size)
    36  	return b[:2]
    37  }
    38  
    39  func (PlainChunkSizeParser) Decode(b []byte) (uint16, error) {
    40  	return binary.BigEndian.Uint16(b), nil
    41  }
    42  
    43  type AEADChunkSizeParser struct {
    44  	Auth *AEADAuthenticator
    45  }
    46  
    47  func (p *AEADChunkSizeParser) SizeBytes() int32 {
    48  	return 2 + int32(p.Auth.Overhead())
    49  }
    50  
    51  func (p *AEADChunkSizeParser) Encode(size uint16, b []byte) []byte {
    52  	binary.BigEndian.PutUint16(b, size-uint16(p.Auth.Overhead()))
    53  	b, err := p.Auth.Seal(b[:0], b[:2])
    54  	common.Must(err)
    55  	return b
    56  }
    57  
    58  func (p *AEADChunkSizeParser) Decode(b []byte) (uint16, error) {
    59  	b, err := p.Auth.Open(b[:0], b)
    60  	if err != nil {
    61  		return 0, err
    62  	}
    63  	return binary.BigEndian.Uint16(b) + uint16(p.Auth.Overhead()), nil
    64  }
    65  
    66  type ChunkStreamReader struct {
    67  	sizeDecoder ChunkSizeDecoder
    68  	reader      *buf.BufferedReader
    69  
    70  	buffer       []byte
    71  	leftOverSize int32
    72  	maxNumChunk  uint32
    73  	numChunk     uint32
    74  }
    75  
    76  func NewChunkStreamReader(sizeDecoder ChunkSizeDecoder, reader io.Reader) *ChunkStreamReader {
    77  	return NewChunkStreamReaderWithChunkCount(sizeDecoder, reader, 0)
    78  }
    79  
    80  func NewChunkStreamReaderWithChunkCount(sizeDecoder ChunkSizeDecoder, reader io.Reader, maxNumChunk uint32) *ChunkStreamReader {
    81  	r := &ChunkStreamReader{
    82  		sizeDecoder: sizeDecoder,
    83  		buffer:      make([]byte, sizeDecoder.SizeBytes()),
    84  		maxNumChunk: maxNumChunk,
    85  	}
    86  	if breader, ok := reader.(*buf.BufferedReader); ok {
    87  		r.reader = breader
    88  	} else {
    89  		r.reader = &buf.BufferedReader{Reader: buf.NewReader(reader)}
    90  	}
    91  
    92  	return r
    93  }
    94  
    95  func (r *ChunkStreamReader) readSize() (uint16, error) {
    96  	if _, err := io.ReadFull(r.reader, r.buffer); err != nil {
    97  		return 0, err
    98  	}
    99  	return r.sizeDecoder.Decode(r.buffer)
   100  }
   101  
   102  func (r *ChunkStreamReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
   103  	size := r.leftOverSize
   104  	if size == 0 {
   105  		r.numChunk++
   106  		if r.maxNumChunk > 0 && r.numChunk > r.maxNumChunk {
   107  			return nil, io.EOF
   108  		}
   109  		nextSize, err := r.readSize()
   110  		if err != nil {
   111  			return nil, err
   112  		}
   113  		if nextSize == 0 {
   114  			return nil, io.EOF
   115  		}
   116  		size = int32(nextSize)
   117  	}
   118  	r.leftOverSize = size
   119  
   120  	mb, err := r.reader.ReadAtMost(size)
   121  	if !mb.IsEmpty() {
   122  		r.leftOverSize -= mb.Len()
   123  		return mb, nil
   124  	}
   125  	return nil, err
   126  }
   127  
   128  type ChunkStreamWriter struct {
   129  	sizeEncoder ChunkSizeEncoder
   130  	writer      buf.Writer
   131  }
   132  
   133  func NewChunkStreamWriter(sizeEncoder ChunkSizeEncoder, writer io.Writer) *ChunkStreamWriter {
   134  	return &ChunkStreamWriter{
   135  		sizeEncoder: sizeEncoder,
   136  		writer:      buf.NewWriter(writer),
   137  	}
   138  }
   139  
   140  func (w *ChunkStreamWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
   141  	const sliceSize = 8192
   142  	mbLen := mb.Len()
   143  	mb2Write := make(buf.MultiBuffer, 0, mbLen/buf.Size+mbLen/sliceSize+2)
   144  
   145  	for {
   146  		mb2, slice := buf.SplitSize(mb, sliceSize)
   147  		mb = mb2
   148  
   149  		b := buf.New()
   150  		w.sizeEncoder.Encode(uint16(slice.Len()), b.Extend(w.sizeEncoder.SizeBytes()))
   151  		mb2Write = append(mb2Write, b)
   152  		mb2Write = append(mb2Write, slice...)
   153  
   154  		if mb.IsEmpty() {
   155  			break
   156  		}
   157  	}
   158  
   159  	return w.writer.WriteMultiBuffer(mb2Write)
   160  }