case LS_STOPPING:
    case LS_REQSENT:
    case LS_ACKRCVD:
    case LS_ACKSENT:
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      /* fall through */
    case LS_STOPPED:
      f->state = LS_STOPPED;
      if( f->callbacks->finished ) {
        (*f->callbacks->finished)(f);
      }
      break;
    
    case LS_OPENED:
      if( f->callbacks->down ) {
        (*f->callbacks->down)(f);
      }
      /* Init restart counter, send Terminate-Request */
      f->retransmits = f->maxtermtransmits;
      fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
            (u_char *) f->term_reason, f->term_reason_len);
      TIMEOUT(fsm_timeout, f, f->timeouttime);
      --f->retransmits;
      
      f->state = LS_STOPPING;
      break;
    
    default:
      FSMDEBUG((LOG_INFO, "%s: Protocol-reject event in state %d (%s)!\n",
            PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
    }
}





/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/

/*
 * fsm_timeout - Timeout expired.
 */
static void
fsm_timeout(void *arg)
{
  fsm *f = (fsm *) arg;

  switch (f->state) {
    case LS_CLOSING:
    case LS_STOPPING:
      if( f->retransmits <= 0 ) {
        FSMDEBUG((LOG_WARNING, "%s: timeout sending Terminate-Request state=%d (%s)\n",
             PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
        /*
         * We've waited for an ack long enough.  Peer probably heard us.
         */
        f->state = (f->state == LS_CLOSING)? LS_CLOSED: LS_STOPPED;
        if( f->callbacks->finished ) {
          (*f->callbacks->finished)(f);
        }
      } else {
        FSMDEBUG((LOG_WARNING, "%s: timeout resending Terminate-Requests state=%d (%s)\n",
             PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
        /* Send Terminate-Request */
        fsm_sdata(f, TERMREQ, f->reqid = ++f->id,
            (u_char *) f->term_reason, f->term_reason_len);
        TIMEOUT(fsm_timeout, f, f->timeouttime);
        --f->retransmits;
      }
      break;

    case LS_REQSENT:
    case LS_ACKRCVD:
    case LS_ACKSENT:
      if (f->retransmits <= 0) {
        FSMDEBUG((LOG_WARNING, "%s: timeout sending Config-Requests state=%d (%s)\n",
         PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
        f->state = LS_STOPPED;
        if( (f->flags & OPT_PASSIVE) == 0 && f->callbacks->finished ) {
          (*f->callbacks->finished)(f);
        }
      } else {
        FSMDEBUG((LOG_WARNING, "%s: timeout resending Config-Request state=%d (%s)\n",
         PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
        /* Retransmit the configure-request */
        if (f->callbacks->retransmit) {
          (*f->callbacks->retransmit)(f);
        }
        fsm_sconfreq(f, 1);    /* Re-send Configure-Request */
        if( f->state == LS_ACKRCVD ) {
          f->state = LS_REQSENT;
        }
      }
      break;

    default:
      FSMDEBUG((LOG_INFO, "%s: Timeout event in state %d (%s)!\n",
          PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
  }
}


/*
 * fsm_rconfreq - Receive Configure-Request.
 */
static void
fsm_rconfreq(fsm *f, u_char id, u_char *inp, int len)
{
  int code, reject_if_disagree;

  FSMDEBUG((LOG_INFO, "fsm_rconfreq(%s): Rcvd id %d state=%d (%s)\n", 
        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
  switch( f->state ) {
    case LS_CLOSED:
      /* Go away, we're closed */
      fsm_sdata(f, TERMACK, id, NULL, 0);
      return;
    case LS_CLOSING:
    case LS_STOPPING:
      return;

    case LS_OPENED:
      /* Go down and restart negotiation */
      if( f->callbacks->down ) {
        (*f->callbacks->down)(f);  /* Inform upper layers */
      }
      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
      break;

    case LS_STOPPED:
      /* Negotiation started by our peer */
      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
      f->state = LS_REQSENT;
      break;
  }
  
  /*
  * Pass the requested configuration options
  * to protocol-specific code for checking.
  */
  if (f->callbacks->reqci) {    /* Check CI */
    reject_if_disagree = (f->nakloops >= f->maxnakloops);
    code = (*f->callbacks->reqci)(f, inp, &len, reject_if_disagree);
  } else if (len) {
    code = CONFREJ;      /* Reject all CI */
  } else {
    code = CONFACK;
  }
  
  /* send the Ack, Nak or Rej to the peer */
  fsm_sdata(f, (u_char)code, id, inp, len);
  
  if (code == CONFACK) {
    if (f->state == LS_ACKRCVD) {
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      f->state = LS_OPENED;
      if (f->callbacks->up) {
        (*f->callbacks->up)(f);  /* Inform upper layers */
      }
    } else {
      f->state = LS_ACKSENT;
    }
    f->nakloops = 0;
  } else {
    /* we sent CONFACK or CONFREJ */
    if (f->state != LS_ACKRCVD) {
      f->state = LS_REQSENT;
    }
    if( code == CONFNAK ) {
      ++f->nakloops;
    }
  }
}


/*
 * fsm_rconfack - Receive Configure-Ack.
 */
static void
fsm_rconfack(fsm *f, int id, u_char *inp, int len)
{
  FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d state=%d (%s)\n",
        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));
  
  if (id != f->reqid || f->seen_ack) {   /* Expected id? */
    return; /* Nope, toss... */
  }
  if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ) {
    /* Ack is bad - ignore it */
    FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)\n",
          PROTO_NAME(f), len));
    return;
  }
  f->seen_ack = 1;
  
  switch (f->state) {
    case LS_CLOSED:
    case LS_STOPPED:
      fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
      break;
    
    case LS_REQSENT:
      f->state = LS_ACKRCVD;
      f->retransmits = f->maxconfreqtransmits;
      break;
    
    case LS_ACKRCVD:
      /* Huh? an extra valid Ack? oh well... */
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      fsm_sconfreq(f, 0);
      f->state = LS_REQSENT;
      break;
    
    case LS_ACKSENT:
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      f->state = LS_OPENED;
      f->retransmits = f->maxconfreqtransmits;
      if (f->callbacks->up) {
        (*f->callbacks->up)(f);  /* Inform upper layers */
      }
      break;
    
    case LS_OPENED:
      /* Go down and restart negotiation */
      if (f->callbacks->down) {
        (*f->callbacks->down)(f);  /* Inform upper layers */
      }
      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
      f->state = LS_REQSENT;
      break;
  }
}


/*
 * fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
 */
static void
fsm_rconfnakrej(fsm *f, int code, int id, u_char *inp, int len)
{
  int (*proc) (fsm *, u_char *, int);
  int ret;

  FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d state=%d (%s)\n",
        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));

  if (id != f->reqid || f->seen_ack) { /* Expected id? */
    return;        /* Nope, toss... */
  }
  proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
  if (!proc || !((ret = proc(f, inp, len)))) {
    /* Nak/reject is bad - ignore it */
    FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)\n",
          PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
    return;
  }
  f->seen_ack = 1;

  switch (f->state) {
    case LS_CLOSED:
    case LS_STOPPED:
      fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
      break;
    
    case LS_REQSENT:
    case LS_ACKSENT:
      /* They didn't agree to what we wanted - try another request */
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      if (ret < 0) {
        f->state = LS_STOPPED;    /* kludge for stopping CCP */
      } else {
        fsm_sconfreq(f, 0);    /* Send Configure-Request */
      }
      break;
    
    case LS_ACKRCVD:
      /* Got a Nak/reject when we had already had an Ack?? oh well... */
      UNTIMEOUT(fsm_timeout, f);  /* Cancel timeout */
      fsm_sconfreq(f, 0);
      f->state = LS_REQSENT;
      break;
    
    case LS_OPENED:
      /* Go down and restart negotiation */
      if (f->callbacks->down) {
        (*f->callbacks->down)(f);  /* Inform upper layers */
      }
      fsm_sconfreq(f, 0);    /* Send initial Configure-Request */
      f->state = LS_REQSENT;
      break;
  }
}


/*
 * fsm_rtermreq - Receive Terminate-Req.
 */
static void
fsm_rtermreq(fsm *f, int id, u_char *p, int len)
{
  LWIP_UNUSED_ARG(p);

  FSMDEBUG((LOG_INFO, "fsm_rtermreq(%s): Rcvd id %d state=%d (%s)\n",
        PROTO_NAME(f), id, f->state, ppperr_strerr[f->state]));

  switch (f->state) {
    case LS_ACKRCVD:
    case LS_ACKSENT:
      f->state = LS_REQSENT;    /* Start over but keep trying */
      break;

    case LS_OPENED:
      if (len > 0) {
        FSMDEBUG((LOG_INFO, "%s terminated by peer (%x)\n", PROTO_NAME(f), p));
      } else {
        FSMDEBUG((LOG_INFO, "%s terminated by peer\n", PROTO_NAME(f)));
      }
      if (f->callbacks->down) {
        (*f->callbacks->down)(f);  /* Inform upper layers */
      }
      f->retransmits = 0;
      f->state = LS_STOPPING;
      TIMEOUT(fsm_timeout, f, f->timeouttime);
      break;
  }

  fsm_sdata(f, TERMACK, (u_char)id, NULL, 0);
}


/*
 * fsm_rtermack - Receive Terminate-Ack.
 */
static void
fsm_rtermack(fsm *f)
{
  FSMDEBUG((LOG_INFO, "fsm_rtermack(%s): state=%d (%s)\n", 
        PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
  
  switch (f->state) {
    case LS_CLOSING:
      UNTIMEOUT(fsm_timeout, f);
      f->state = LS_CLOSED;
      if( f->callbacks->finished ) {
        (*f->callbacks->finished)(f);
      }
      break;

    case LS_STOPPING:
      UNTIMEOUT(fsm_timeout, f);
      f->state = LS_STOPPED;
      if( f->callbacks->finished ) {
        (*f->callbacks->finished)(f);
      }
      break;
    
    case LS_ACKRCVD:
      f->state = LS_REQSENT;
      break;
    
    case LS_OPENED:
      if (f->callbacks->down) {
        (*f->callbacks->down)(f);  /* Inform upper layers */
      }
      fsm_sconfreq(f, 0);
      break;
  }
}


/*
 * fsm_rcoderej - Receive an Code-Reject.
 */
static void
fsm_rcoderej(fsm *f, u_char *inp, int len)
{
  u_char code, id;
  
  FSMDEBUG((LOG_INFO, "fsm_rcoderej(%s): state=%d (%s)\n", 
        PROTO_NAME(f), f->state, ppperr_strerr[f->state]));
  
  if (len < HEADERLEN) {
    FSMDEBUG((LOG_INFO, "fsm_rcoderej: Rcvd short Code-Reject packet!\n"));
    return;
  }
  GETCHAR(code, inp);
  GETCHAR(id, inp);
  FSMDEBUG((LOG_WARNING, "%s: Rcvd Code-Reject for code %d, id %d\n",
        PROTO_NAME(f), code, id));
  
  if( f->state == LS_ACKRCVD ) {
    f->state = LS_REQSENT;
  }
}


/*
 * fsm_sconfreq - Send a Configure-Request.
 */
static void
fsm_sconfreq(fsm *f, int retransmit)
{
  u_char *outp;
  int cilen;
  
  if( f->state != LS_REQSENT && f->state != LS_ACKRCVD && f->state != LS_ACKSENT ) {
    /* Not currently negotiating - reset options */
    if( f->callbacks->resetci ) {
      (*f->callbacks->resetci)(f);
    }
    f->nakloops = 0;
  }
  
  if( !retransmit ) {
    /* New request - reset retransmission counter, use new ID */
    f->retransmits = f->maxconfreqtransmits;
    f->reqid = ++f->id;
  }
  
  f->seen_ack = 0;
  
  /*
   * Make up the request packet
   */
  outp = outpacket_buf[f->unit] + PPP_HDRLEN + HEADERLEN;
  if( f->callbacks->cilen && f->callbacks->addci ) {
    cilen = (*f->callbacks->cilen)(f);
    if( cilen > peer_mru[f->unit] - (int)HEADERLEN ) {
      cilen = peer_mru[f->unit] - HEADERLEN;
    }
    if (f->callbacks->addci) {
      (*f->callbacks->addci)(f, outp, &cilen);
    }
  } else {
    cilen = 0;
  }

  /* send the request to our peer */
  fsm_sdata(f, CONFREQ, f->reqid, outp, cilen);
  
  /* start the retransmit timer */
  --f->retransmits;
  TIMEOUT(fsm_timeout, f, f->timeouttime);
  
  FSMDEBUG((LOG_INFO, "%s: sending Configure-Request, id %d\n",
        PROTO_NAME(f), f->reqid));
}

#endif /* PPP_SUPPORT */