108 lines
2.0 KiB
Go
108 lines
2.0 KiB
Go
package proxy
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import (
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"bufio"
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"errors"
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"io"
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"log"
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"math"
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"net"
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"strings"
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)
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// A TelnetWriter can be used to print something at the other end
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// of a telnet connection. It implements the io.Writer interface.
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type TelnetWriter struct {
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conn net.Conn
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}
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// Write writes its parameter to the telnet connection.
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// A trailing newline is always appended.
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// It returns the number of bytes written and an error.
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func (tw *TelnetWriter) Write(p []byte) (n int, err error) {
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return tw.conn.Write(append(p, '\n'))
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}
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var telnetCh = make(chan struct{})
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func telnetServer() error {
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ln, err := net.Listen("tcp", Conf().TelnetAddr)
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if err != nil {
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return err
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}
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defer ln.Close()
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log.Print("{←|⇶} listen telnet ", ln.Addr())
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for {
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select {
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case <-telnetCh:
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return nil
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default:
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conn, err := ln.Accept()
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if err != nil {
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log.Print("{←|⇶} ", err)
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continue
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}
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go handleTelnet(conn)
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}
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}
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}
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func handleTelnet(conn net.Conn) {
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tlog := func(dir string, v ...interface{}) {
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format := "{%s} %s {←|⇶}"
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format += strings.Repeat(" %v", len(v))
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log.Printf(format, append([]interface{}{
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conn.RemoteAddr(),
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dir,
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}, v...)...)
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}
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tlog("<->", "telnet connect")
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defer tlog("<->", "telnet disconnect")
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defer conn.Close()
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readString := func(delim byte) (string, error) {
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s, err := bufio.NewReader(conn).ReadString(delim)
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i := int(math.Max(float64(len(s)-2), 1))
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s = s[:i]
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return s, err
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}
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writeString := func(s string) (n int, err error) {
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return io.WriteString(conn, s)
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}
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writeString("mt-multiserver-proxy console\n")
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writeString("Type \\quit or \\q to disconnect.\n")
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for {
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writeString(Conf().CmdPrefix)
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s, err := readString('\n')
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if err != nil {
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if errors.Is(err, io.EOF) {
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return
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}
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log.Print("{←|⇶} ", err)
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continue
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}
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tlog("-->", "telnet command", s)
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if s == "\\quit" || s == "\\q" {
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return
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}
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result := onTelnetMsg(tlog, &TelnetWriter{conn: conn}, s)
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if result != "" {
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writeString(result)
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}
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}
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}
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