71 lines
1.5 KiB
Go
71 lines
1.5 KiB
Go
package shadow
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"net"
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)
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var (
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AppDataHeader = []byte{0x17, 0x3, 0x3}
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HeaderLength = len(AppDataHeader)
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)
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type PackAppData struct {
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Conn net.Conn
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}
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func (m PackAppData) Read(p []byte) (n int, err error) {
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buf := make([]byte, 32*1024+HeaderLength+2)
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headRead, err := io.ReadAtLeast(m.Conn, buf[0:HeaderLength+2], HeaderLength+2)
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if err != nil {
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fmt.Printf("Read header error: %v\n", err)
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return 0, err
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}
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if headRead < HeaderLength+2 {
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return 0, errors.New("Read header failed")
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}
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if bytes.Equal(buf[0:HeaderLength], AppDataHeader) {
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payLoadLength := int(binary.BigEndian.Uint16(buf[HeaderLength : HeaderLength+2]))
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sum := 0
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for sum < payLoadLength {
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r, e := m.Conn.Read(buf[HeaderLength+2+sum : HeaderLength+2+payLoadLength])
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if e != nil {
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if e == io.EOF {
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break
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} else {
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return 0, e
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}
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}
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copy(p[sum:], buf[HeaderLength+2+sum:HeaderLength+2+sum+r])
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sum += r
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}
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return sum, err
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} else {
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fmt.Printf("Invalid header")
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return 0, errors.New("invalid header")
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}
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}
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func (m PackAppData) Write(p []byte) (n int, err error) {
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lenNum := make([]byte, 2)
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binary.BigEndian.PutUint16(lenNum, uint16(len(p)))
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packetBuf := bytes.NewBuffer(AppDataHeader)
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packetBuf.Write(lenNum)
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packetBuf.Write(p)
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write, err := m.Conn.Write(packetBuf.Bytes())
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write = write - HeaderLength - 2
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return write, err
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}
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func (m PackAppData) Close() error {
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return m.Conn.Close()
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}
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