Internet on FIRE

/*

 *        BIRD Library -- Token Bucket Filter

 *

 *        (c) 2014 Ondrej Zajicek <santiago@crfreenet.org>

 *        (c) 2014 CZ.NIC z.s.p.o.

 *

 *        Can be freely distributed and used under the terms of the GNU GPL.

 */

#include "nest/bird.h"

#include "lib/timer.h"

int

tbf_limit(struct tbf *f)

{

  btime delta = current_time() - f->timestamp;

  if (delta > 0)

  {

    u64 next = f->count + delta * f->rate;

    u64 burst = (u64) f->burst << 20;

    f->count = MIN(next, burst);

    f->timestamp += delta;

  }

  if (f->count < 1000000)

  {

    f->drop++;

    return 1;

  }

  else

  {

    f->count -= 1000000;

    f->drop = 0;

    return 0;

  }

}