107 lines
1.9 KiB
Go
107 lines
1.9 KiB
Go
package main
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import (
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"flag"
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"io"
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"log"
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"net"
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)
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var key int
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var listen string
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var connect string
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func main() {
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flag.IntVar(&key, "key", 170, "key to xor the data")
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flag.StringVar(&listen, "listen", ":8081", "listen on ip and port")
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flag.StringVar(&connect, "connect", ":8080", "forward to ip and port")
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flag.Parse()
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if key < 0 || key > 255 {
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flag.PrintDefaults()
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log.Fatal("key is not one byte")
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}
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// check and parse address
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conn, err := net.ResolveTCPAddr("tcp", connect)
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if err != nil {
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flag.PrintDefaults()
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log.Fatal(err)
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}
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// listen on address
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ln, err := net.Listen("tcp", listen)
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if err != nil {
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flag.PrintDefaults()
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log.Fatal(err)
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}
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log.Printf("listening on %v", ln.Addr())
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log.Printf("will connect to %v", conn)
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for i := 0; ; i++ {
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// accept new connection
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c, err := ln.Accept()
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if err != nil {
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log.Fatal(err)
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}
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log.Printf("connection %v from %v", i, c.RemoteAddr())
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cn, err := net.DialTCP("tcp", nil, conn)
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if err != nil {
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c.Close()
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log.Print(err)
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continue
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}
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go pipe(c, cn, byte(key), i)
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go pipe(cn, c, byte(key), i)
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}
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}
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func pipe(w io.WriteCloser, r io.ReadCloser, key byte, count int) {
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n, err := copyBufferXor(w, r, key)
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r.Close()
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w.Close()
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log.Printf("connection %v closed, %v bytes", count, n)
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opError, ok := err.(*net.OpError)
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if err != nil && (!ok || opError.Op != "readfrom") {
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log.Printf("warning! %v", err)
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}
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}
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func copyBufferXor(dst io.Writer, src io.Reader, key byte) (written int64, err error) {
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buf := make([]byte, 32*1024)
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for {
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nr, er := src.Read(buf)
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for i := 0; i < nr; i++ {
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buf[i] = buf[i] ^ key
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}
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if nr > 0 {
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nw, ew := dst.Write(buf[0:nr])
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if nw > 0 {
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written += int64(nw)
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}
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if ew != nil {
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err = ew
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break
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}
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if nr != nw {
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err = io.ErrShortWrite
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break
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}
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}
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if er != nil {
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if er != io.EOF {
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err = er
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}
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break
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}
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}
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return written, err
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}
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