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// Copyright (C) 2019 LEAP
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package sip2
import (
//"github.com/reiver/go-telnet"
/* TODO this one exposes DialTimeout */
"github.com/linxiaozhi/go-telnet"
"log"
"net"
"time"
)
// The terminator can be configured differently for different SIP endpoints.
// This gets set in sip2.auth according to an environment variable
var telnetTerminator string
var telnetTimeout string = "2000ms"
func telnetRead(conn gote.Connection) (string, error) {
var buffer [1]byte
recvData := buffer[:]
var n int
var err error
var out string
for {
setDeadline(conn)
n, err = conn.Read(recvData)
if n <= 0 || err != nil {
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
log.Println("telnet: read timeout:", err)
return "", err
} else {
// some other error, do something else, for example create new conn
/* TODO -- should modify attributes of the error, or raise a non-recoverable one */
/* ie, broken pipe errors will not be solved by retries */
log.Println("telnet: read error:", err)
return "", err
}
} else {
out += string(recvData)
}
if len(out) > 1 && out[len(out)-len(telnetTerminator):] == telnetTerminator {
break
}
}
return out, nil
}
func telnetSend(conn gote.Connection, command string) error {
var commandBuffer []byte
setDeadline(conn)
for _, char := range command {
commandBuffer = append(commandBuffer, byte(char))
}
var crlfBuffer [2]byte = [2]byte{'\r', '\n'}
crlf := crlfBuffer[:]
_, err := conn.Write(commandBuffer)
if err != nil {
return err
}
_, err = conn.Write(crlf)
if err != nil {
return err
}
return nil
}
func setDeadline(conn gote.Connection) error {
/* TODO do we need to set deadline explicitely here? */
t, err := time.ParseDuration(telnetTimeout)
if err != nil {
log.Println("telnet: error parsing duration")
return err
}
err = conn.SetDeadline(time.Now().Add(t * time.Second))
if err != nil {
log.Println("telnet: error setting deadline")
return err
}
return nil
}
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