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@@ -0,0 +1,111 @@
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+package crypto
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+
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+import (
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+ "crypto/cipher"
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+ "errors"
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+ "io"
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+ "v2ray.com/core/common/alloc"
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+ "v2ray.com/core/common/serial"
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+)
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+
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+var (
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+ ErrAuthenticationFailed = errors.New("Authentication failed.")
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+ errInsufficientBuffer = errors.New("Insufficient buffer.")
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+)
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+
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+type BytesGenerator func() []byte
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+
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+type AuthenticationReader struct {
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+ aead cipher.AEAD
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+ buffer *alloc.Buffer
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+ reader io.Reader
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+ ivGen BytesGenerator
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+ extraGen BytesGenerator
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+
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+ chunk []byte
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+}
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+
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+func NewAuthenticationReader(aead cipher.AEAD, reader io.Reader, ivGen BytesGenerator, extraGen BytesGenerator) *AuthenticationReader {
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+ return &AuthenticationReader{
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+ aead: aead,
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+ buffer: alloc.NewLocalBuffer(32 * 1024),
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+ reader: reader,
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+ ivGen: ivGen,
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+ extraGen: extraGen,
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+ }
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+}
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+
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+func (v *AuthenticationReader) NextChunk() error {
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+ size := int(serial.BytesToUint16(v.buffer.BytesTo(2)))
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+ if size > v.buffer.Len()-2 {
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+ return errInsufficientBuffer
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+ }
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+ cipherChunk := v.buffer.BytesRange(2, size+2)
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+ plainChunk, err := v.aead.Open(cipherChunk, v.ivGen(), cipherChunk, v.extraGen())
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+ if err != nil {
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+ return err
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+ }
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+ v.chunk = plainChunk
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+ return nil
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+}
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+
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+func (v *AuthenticationReader) CopyChunk(b []byte) int {
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+ nBytes := copy(b, v.chunk)
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+ if nBytes == len(v.chunk) {
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+ v.chunk = nil
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+ } else {
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+ v.chunk = v.chunk[nBytes:]
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+ }
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+ return nBytes
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+}
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+
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+func (v *AuthenticationReader) Read(b []byte) (int, error) {
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+ if len(v.chunk) > 0 {
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+ nBytes := v.CopyChunk(b)
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+ return nBytes, nil
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+ }
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+
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+ err := v.NextChunk()
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+ if err == errInsufficientBuffer {
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+ v.buffer.FillFrom(v.reader)
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+ } else if err != nil {
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+ return 0, io.ErrUnexpectedEOF
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+ }
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+
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+ totalBytes := 0
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+ for {
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+ totalBytes += v.CopyChunk(b)
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+ if len(b) == 0 {
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+ break
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+ }
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+ if err := v.NextChunk(); err != nil {
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+ break
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+ }
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+ }
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+ return totalBytes, nil
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+}
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+
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+type AuthenticationWriter struct {
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+ aead cipher.AEAD
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+ buffer []byte
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+ writer io.Writer
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+ ivGen BytesGenerator
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+ extraGen BytesGenerator
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+}
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+
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+func NewAuthenticationWriter(aead cipher.AEAD, writer io.Writer, ivGen BytesGenerator, extraGen BytesGenerator) *AuthenticationWriter {
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+ return &AuthenticationWriter{
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+ aead: aead,
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+ buffer: make([]byte, 32*1024),
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+ writer: writer,
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+ ivGen: ivGen,
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+ extraGen: extraGen,
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+ }
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+}
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+
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+func (v *AuthenticationWriter) Write(b []byte) (int, error) {
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+ cipherChunk := v.aead.Seal(v.buffer[2:], v.ivGen(), b, v.extraGen())
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+ serial.Uint16ToBytes(uint16(len(cipherChunk)), b[:0])
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+ _, err := v.writer.Write(v.buffer[:2+len(cipherChunk)])
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+ return len(b), err
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+}
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