/*

    Terminal Mixer - multi-point multi-user access to terminal applications

    Copyright (C) 2007  Lluís Batlle i Rossell

    Please find the license in the provided COPYING file.

*/

#include <stdlib.h>

#include "main.h"

#include "filter.h"

enum TState

{

    NOTHING,

    RECEIVED_IAC,

    RECEIVED_OPT,

    SUBNEGOTIATED

};

enum Chars

{

    IAC = 255,

    SB = 250,

    SE = 240

};

struct FTelnet

{

    struct FFilter base;

    enum TState state;

};

static void ftelnet_reset(struct FFilter *ff)

{

    struct FTelnet *ft = (struct FTelnet *) ff;

    ft->state = NOTHING;

}

static int ftelnet_function(struct FFilter *ff, unsigned char c)

{

    struct FTelnet *ft = (struct FTelnet *) ff;

    switch (ft->state)

    {

        case NOTHING:

            if (c == IAC)

            {

                ft->state = RECEIVED_IAC;

                ft->base.matched++;

            }

            break;

        case RECEIVED_IAC:

            if (c == SB)

            {

                ft->state = SUBNEGOTIATED;

                ft->base.matched++;

            } else /* Received the control char */

            {

                ft->state = RECEIVED_OPT;

                ft->base.matched++;

            }

            break;

        case RECEIVED_OPT:

            ft->base.matched++;

            return 1;

            break;

        case SUBNEGOTIATED:

            ft->base.matched++;

            if (c == SE)

            {

                return 1;

            }

            break;

    }

    return 0;

}

struct FFilter *new_ftelnet()

{

    struct FTelnet *ft;

    ft = (struct FTelnet *) malloc(sizeof(*ft));

    ft->state = NOTHING;

    ft->base.matched = 0;

    ft->base.function = ftelnet_function;

    ft->base.reset = ftelnet_reset;

    ft->base.callback = 0;

    return (struct FFilter *) ft;

}