Re: Telnet command question

For my send, I just use the Send member of the AsyncSocket class. For now, I
just check Ethereal to see that all data transmitted from the client app (and
it does).

Here's my state "machine" function:

BOOL IRCamera::TelnetInit()
{
    unsigned char buff[100], current_byte = 0;
    //telnet states
    //1 - starting state
    //2 - received IAC, command to follow
    //3 - received DO command, waiting for option
    //4 - received Terminal, send back will negotiate terminal
    //5 - received SB, waiting for option
    //6 - received terminal, waiting for parameter
    //7 - received send terminal type, return to state 1
    //8 - received SB-end, send back terminal type ANSI
    //9 - received WILL, waiting for option
    //10 - received 01 (echo), send back don't echo
    //11 - received 03 suppress, send back nothing
    //12 - received WONT, wait for option
    //13 - received 01 (echo), done
    //14 - received 01 (echo), done

    while(m_strRecvBuff.GetLength() > 0){
        memset(buff, 0, sizeof(buff));
        current_byte = m_strRecvBuff[0];
        switch(current_byte){
        case 0xff: // IAC - telnet commands to follow
            m_strRecvBuff.Delete(0,1);
            telnet_state = 2;
            break;
        case 0xfd: // DO command
            m_strRecvBuff.Delete(0,1);
            telnet_state = 3;
            break;
        case 0x18: // terminal type
            m_strRecvBuff.Delete(0,1);
            if(telnet_state == 3){
                //when received IAC-DO-Terminal type, send back IAC WILL Terminal type
                telnet_state = 1;
                buff[0] = 0xff; // IAC
                buff[1] = 0xfb; // WILL
                buff[2] = 0x18; // Terminal type
                pAsyncClient->Send(buff, 3, 0);
            }
            else if(telnet_state == 5){
                telnet_state = 6; // waiting for parameter
            }
            break;
        case 0xfa: // Sub Option
            m_strRecvBuff.Delete(0,1);
            telnet_state = 5;
            break;
        case 0x01: // Send terminal type or ECHO
            m_strRecvBuff.Delete(0,1);
            if(telnet_state == 6)
                telnet_state = 1; //waiting for sub option end
            else if(telnet_state == 12){
                current_state = 1; //received wont echo
            }
            else if(telnet_state == 9){
                //state 10
                buff[0] = 0xff; // IAC
                buff[1] = 0xfe; // DONT
                buff[2] = 0x01; // echo
                pAsyncClient->Send(buff, 3, 0);
                telnet_state = 1;
            }
            else{
                //state 14
                buff[0] = 0xff; // IAC
                buff[1] = 0xfc; // WONT
                buff[2] = 0x01; // echo
                pAsyncClient->Send(buff, 3, 0);
                telnet_state = 1;
            }
            break;
        case 0xf0: // SB (sub-option) end
            //state 8
            m_strRecvBuff.Delete(0,1);
            telnet_state = 1;
            buff[0] = 0xff; // IAC
            buff[1] = 0xfa; // SB
            buff[2] = 0x18; // terminal type
            buff[3] = 0x00; // here's my terminal type
            buff[4] = 0x41; // 'A'
            buff[5] = 0x4e; // 'N'
            buff[6] = 0x53; // 'S'
            buff[7] = 0x49; // 'I'
            buff[8] = 0xff; // IAC
            buff[9] = 0xf0; // SB end
            pAsyncClient->Send(buff, 10,0);
            break;
        case 0xfb: // WILL
            //state 9
            m_strRecvBuff.Delete(0,1);
            telnet_state = 9;
            break;
        case 0xfc: //WONT
            //state 12
            m_strRecvBuff.Delete(0,1);
            telnet_state = 12;
            break;
        case 0x03: // Suppress Go ahead
            //state 11
            m_strRecvBuff.Delete(0,1);
            telnet_state = 1;
            buff[0] = 0xff; // IAC
            buff[1] = 0xfd; // DO
            buff[2] = 0x03; // Suppress Go ahead
            pAsyncClient->Send(buff, 3, 0);
            break;
        case 0xfe: // DONT
            m_strRecvBuff.Delete(0,1);
            break;
        default:
            m_strRecvBuff.Delete(0,1);
            break;
        }
    }

    return 0;
}

And when I send, an example follows:

//off denotes lenscover "off" or open, on denotes lenscover "on" or closed
int IRCamera::LensCover(int status){
    CString temp = "lenscover ";
    if(status)
        temp += "on\r";
    else
        temp += "off\r";
    return pAsyncClient->Send(temp, temp.GetLength(),0);

}

If I send a command after everything settles down, it responds back. What
gives? Thanks.

Vinoj
"Norbert Unterberg" wrote: