package v2raywebsocket import ( "encoding/binary" "io" "math/rand" "github.com/sagernet/sing/common/buf" "github.com/sagernet/sing/common/bufio" N "github.com/sagernet/sing/common/network" "github.com/sagernet/ws" ) type Writer struct { writer N.ExtendedWriter isServer bool } func NewWriter(writer io.Writer, state ws.State) *Writer { return &Writer{ bufio.NewExtendedWriter(writer), state == ws.StateServerSide, } } func (w *Writer) WriteBuffer(buffer *buf.Buffer) error { var payloadBitLength int dataLen := buffer.Len() data := buffer.Bytes() if dataLen < 126 { payloadBitLength = 1 } else if dataLen < 65536 { payloadBitLength = 3 } else { payloadBitLength = 9 } var headerLen int headerLen += 1 // FIN / RSV / OPCODE headerLen += payloadBitLength if !w.isServer { headerLen += 4 // MASK KEY } header := buffer.ExtendHeader(headerLen) header[0] = byte(ws.OpBinary) | 0x80 if w.isServer { header[1] = 0 } else { header[1] = 1 << 7 } if dataLen < 126 { header[1] |= byte(dataLen) } else if dataLen < 65536 { header[1] |= 126 binary.BigEndian.PutUint16(header[2:], uint16(dataLen)) } else { header[1] |= 127 binary.BigEndian.PutUint64(header[2:], uint64(dataLen)) } if !w.isServer { maskKey := rand.Uint32() binary.BigEndian.PutUint32(header[1+payloadBitLength:], maskKey) ws.Cipher(data, *(*[4]byte)(header[1+payloadBitLength:]), 0) } return w.writer.WriteBuffer(buffer) } func (w *Writer) FrontHeadroom() int { return 14 }