84 lines
2.0 KiB
Go
84 lines
2.0 KiB
Go
package main
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import (
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"bufio"
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"bytes"
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"flag"
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"fmt"
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"net"
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"github.com/golang/glog"
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)
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var (
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saddr = flag.String("saddr", ":11143", "address to listen on")
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caddr = flag.String("caddr", "localhost:10143", "remote address to connect to")
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)
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// scanLines reimplements bufio.ScanLines without eating '\r' in the input.
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func scanLines(data []byte, atEOF bool) (advance int, token []byte, err error) {
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if atEOF && len(data) == 0 {
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return 0, nil, nil
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}
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if i := bytes.IndexByte(data, '\n'); i >= 0 {
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// We have a full newline-terminated line.
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return i + 1, data[0:i], nil
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}
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// If we're at EOF, we have a final, non-terminated line. Return it.
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if atEOF {
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return len(data), data, nil
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}
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// Request more data.
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return 0, nil, nil
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}
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func prefixCopy(prefix string, src, dst net.Conn) {
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defer src.Close()
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defer dst.Close()
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glog.Infof("%s proxying %s -> %s", prefix, src.LocalAddr(), dst.RemoteAddr())
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scanner := bufio.NewScanner(src)
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scanner.Split(scanLines)
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for scanner.Scan() {
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glog.Infoln(prefix, scanner.Text()) // Println will add back the final '\n'
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if _, err := fmt.Fprintln(dst, scanner.Text()); err != nil {
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glog.Errorf("%s error writing to dst: %v", prefix, err)
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return
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}
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}
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if err := scanner.Err(); err != nil {
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glog.Errorf("%s error reading from src: %v", prefix, err)
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return
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}
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}
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func proxy(id int, client net.Conn, remoteAddr string) {
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remote, err := net.Dial("tcp", remoteAddr)
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if err != nil {
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glog.Errorf("Failed to dial %s: %v", remoteAddr, err)
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return
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}
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go prefixCopy(fmt.Sprintf("[%d] S:", id), remote, client)
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go prefixCopy(fmt.Sprintf("[%d] C:", id), client, remote)
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}
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func main() {
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flag.Parse()
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defer glog.Flush()
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glog.Infof("Proxying %s -> %s", *saddr, *caddr)
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ln, err := net.Listen("tcp", *saddr)
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if err != nil {
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glog.Exitf("Failed to listen on %s: %v", *saddr, err)
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}
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var id int
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for {
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conn, err := ln.Accept()
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if err != nil {
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glog.Exitf("Failed to accept on %s: %v", *saddr, err)
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}
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proxy(id, conn, *caddr)
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id++
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}
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}
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