bgp_damp.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

          if (bdi->lastrecord == BGP_RECORD_UPDATE)
            return 1;
          else
            return 0;
        }
    }
  else
    {
      t_diff = t_now - bdi->t_updated;
      bdi->penalty = bgp_damp_decay (t_diff, bdi->penalty);

      if (bdi->penalty <= damp->reuse_limit / 2.0)
        {
          /* release the bdi, bdi->binfo. */  
          bgp_damp_info_free (bdi, 1);
          return 0;
        }            
      else
        bdi->t_updated = t_now;
    }       
  return 0;
}

void
bgp_damp_info_free (struct bgp_damp_info *bdi, int withdraw)
{
  struct bgp_info *binfo;
  void bgp_info_delete (struct bgp_node *, struct bgp_info *);
  void bgp_info_free (struct bgp_info *);

  if (! bdi)
    return;

  binfo = bdi->binfo;
  binfo->damp_info = NULL;

  if (CHECK_FLAG (binfo->flags, BGP_INFO_DAMPED))
    bgp_reuse_list_delete (bdi);
  else
    BGP_DAMP_LIST_DEL (damp, bdi);

  UNSET_FLAG (binfo->flags, BGP_INFO_DAMPED);
  UNSET_FLAG (binfo->flags, BGP_INFO_HISTORY);

  if (bdi->lastrecord == BGP_RECORD_WITHDRAW && withdraw)
    {
      bgp_info_delete (bdi->rn, binfo);
      bgp_info_free (binfo);
      bgp_unlock_node (bdi->rn);
    }
  XFREE (MTYPE_BGP_DAMP_INFO, bdi);
}

void
bgp_damp_parameter_set (int hlife, int reuse, int sup, int maxsup)
{
  double reuse_max_ratio;
  int i;
  double j;
	
  damp->suppress_value = sup;
  damp->half_life = hlife;
  damp->reuse_limit = reuse;
  damp->max_suppress_time = maxsup;

  /* Initialize params per bgp_damp_config. */
  damp->reuse_index_size = REUSE_ARRAY_SIZE;

  damp->ceiling = (int)(damp->reuse_limit * (pow(2, (double)damp->max_suppress_time/damp->half_life))); 

  /* Decay-array computations */
  damp->decay_array_size = ceil ((double) damp->max_suppress_time / DELTA_T);
  damp->decay_array = XMALLOC (MTYPE_BGP_DAMP_ARRAY,
			       sizeof(double) * (damp->decay_array_size));
  damp->decay_array[0] = 1.0;
  damp->decay_array[1] = exp ((1.0/((double)damp->half_life/DELTA_T)) * log(0.5));

  /* Calculate decay values for all possible times */
  for (i = 2; i < damp->decay_array_size; i++)
    damp->decay_array[i] = damp->decay_array[i-1] * damp->decay_array[1];
	
  /* Reuse-list computations */
  i = ceil ((double)damp->max_suppress_time / DELTA_REUSE) + 1;
  if (i > REUSE_LIST_SIZE || i == 0)
    i = REUSE_LIST_SIZE;
  damp->reuse_list_size = i; 

  damp->reuse_list = XCALLOC (MTYPE_BGP_DAMP_ARRAY, 
			      damp->reuse_list_size 
			      * sizeof (struct bgp_reuse_node *));
  memset (damp->reuse_list, 0x00, 
          damp->reuse_list_size * sizeof (struct bgp_reuse_node *));  

  /* Reuse-array computations */
  damp->reuse_index = XMALLOC (MTYPE_BGP_DAMP_ARRAY, 
			       sizeof(int) * damp->reuse_index_size);
  memset (damp->reuse_index, 0x00,
          damp->reuse_list_size * sizeof (int));

  reuse_max_ratio = (double)damp->ceiling/damp->reuse_limit;
  j = (exp((double)damp->max_suppress_time/damp->half_life) * log10(2.0));
  if ( reuse_max_ratio > j && j != 0 )
    reuse_max_ratio = j;

  damp->scale_factor = (double)damp->reuse_index_size/(reuse_max_ratio - 1);

  for (i = 0; i < damp->reuse_index_size; i++)
    {
      damp->reuse_index[i] = 
	(int)(((double)damp->half_life / DELTA_REUSE)
	      * log10 (1.0 / (damp->reuse_limit * ( 1.0 + ((double)i/damp->scale_factor)))) / log10(0.5));
    }
}

int
bgp_damp_enable (struct bgp *bgp, afi_t afi, safi_t safi, int half,
		 int reuse, int suppress, int max)
{
  if (CHECK_FLAG (bgp->af_flags[afi][safi], BGP_CONFIG_DAMPENING))
    {
      if (damp->half_life == half
	  && damp->reuse_limit == reuse
	  && damp->suppress_value == suppress
	  && damp->max_suppress_time == max)
	return 0;
      bgp_damp_disable (bgp, afi, safi);
    }

  SET_FLAG (bgp->af_flags[afi][safi], BGP_CONFIG_DAMPENING);
  bgp_damp_parameter_set (half, reuse, suppress, max);

  /* Register reuse timer.  */
  if (! damp->t_reuse)
    damp->t_reuse = 
      thread_add_timer (master, bgp_reuse_timer, NULL, DELTA_REUSE);

  return 0;
}

void
bgp_damp_config_clean (struct bgp_damp_config *damp)
{
  /* Free decay array */
  XFREE (MTYPE_BGP_DAMP_ARRAY, damp->decay_array);

  /* Free reuse index array */
  XFREE (MTYPE_BGP_DAMP_ARRAY, damp->reuse_index);

  /* Free reuse list array. */
  XFREE (MTYPE_BGP_DAMP_ARRAY, damp->reuse_list);
}

/* Clean all the bgp_damp_info stored in reuse_list. */
void
bgp_damp_info_clean ()
{
  int i;
  struct bgp_damp_info *bdi, *next;

  damp->reuse_offset = 0;

  for (i = 0; i < damp->reuse_list_size; i++)
    {
      if (! damp->reuse_list[i])
	continue;

      for (bdi = damp->reuse_list[i]; bdi; bdi = next)
	{
	  next = bdi->next;
	  bgp_damp_info_free (bdi, 1);
	}
      damp->reuse_list[i] = NULL;
    }

  for (bdi = damp->no_reuse_list; bdi; bdi = next)
    {
      next = bdi->next;
      bgp_damp_info_free (bdi, 1);
    }
  damp->no_reuse_list = NULL;
}

int
bgp_damp_disable (struct bgp *bgp, afi_t afi, safi_t safi)
{
  /* Cancel reuse thread. */
  if (damp->t_reuse )
    thread_cancel (damp->t_reuse);
  damp->t_reuse = NULL;

  /* Clean BGP dampening information.  */
  bgp_damp_info_clean ();

  /* Clear configuration */
  bgp_damp_config_clean (&bgp_damp_cfg);

  UNSET_FLAG (bgp->af_flags[afi][safi], BGP_CONFIG_DAMPENING);
  return 0;
}

int
bgp_config_write_damp (struct vty *vty)
{
  if (&bgp_damp_cfg)
    {
      if (bgp_damp_cfg.half_life == DEFAULT_HALF_LIFE*60
	  && bgp_damp_cfg.reuse_limit == DEFAULT_REUSE
	  && bgp_damp_cfg.suppress_value == DEFAULT_SUPPRESS
	  && bgp_damp_cfg.max_suppress_time == bgp_damp_cfg.half_life*4)
	vty_out (vty, " bgp dampening%s", VTY_NEWLINE);
      else if (bgp_damp_cfg.half_life != DEFAULT_HALF_LIFE*60
	       && bgp_damp_cfg.reuse_limit == DEFAULT_REUSE
	       && bgp_damp_cfg.suppress_value == DEFAULT_SUPPRESS
	       && bgp_damp_cfg.max_suppress_time == bgp_damp_cfg.half_life*4)
	vty_out (vty, " bgp dampening %d%s",
		 bgp_damp_cfg.half_life/60,
		 VTY_NEWLINE);
      else
	vty_out (vty, " bgp dampening %d %d %d %d%s",
		 bgp_damp_cfg.half_life/60,
		 bgp_damp_cfg.reuse_limit,
		 bgp_damp_cfg.suppress_value,
		 bgp_damp_cfg.max_suppress_time/60,
		 VTY_NEWLINE);
      return 1;
    }
  return 0;
}

#define BGP_UPTIME_LEN 25

char *
bgp_get_reuse_time (int penalty, char *buf, size_t len)
{
  time_t reuse_time = 0;
  struct tm *tm = NULL;

  if (penalty > damp->reuse_limit)
    {
      reuse_time = (int) (DELTA_T * ((log((double)damp->reuse_limit/penalty))/(log(damp->decay_array[1])))); 

      if (reuse_time > damp->max_suppress_time)
	reuse_time = damp->max_suppress_time;

      tm = gmtime (&reuse_time);
    }
  else 
    reuse_time = 0;

  /* Making formatted timer strings. */
#define ONE_DAY_SECOND 60*60*24
#define ONE_WEEK_SECOND 60*60*24*7
  if (reuse_time == 0)
    snprintf (buf, len, "00:00:00");
  else if (reuse_time < ONE_DAY_SECOND)
    snprintf (buf, len, "%02d:%02d:%02d", 
              tm->tm_hour, tm->tm_min, tm->tm_sec);
  else if (reuse_time < ONE_WEEK_SECOND)
    snprintf (buf, len, "%dd%02dh%02dm", 
              tm->tm_yday, tm->tm_hour, tm->tm_min);
  else
    snprintf (buf, len, "%02dw%dd%02dh", 
              tm->tm_yday/7, tm->tm_yday - ((tm->tm_yday/7) * 7), tm->tm_hour); 

  return buf;
}
 
void
bgp_damp_info_vty (struct vty *vty, struct bgp_info *binfo)  
{
  struct bgp_damp_info *bdi;
  time_t t_now, t_diff;
  char timebuf[BGP_UPTIME_LEN];
  int penalty;

  /* BGP dampening information.  */
  bdi = binfo->damp_info;

  /* If dampening is not enabled or there is no dampening information,
     return immediately.  */
  if (! damp || ! bdi)
    return;

  /* Calculate new penalty.  */
  t_now = time (NULL);
  t_diff = t_now - bdi->t_updated;
  penalty = bgp_damp_decay (t_diff, bdi->penalty);

  vty_out (vty, "      Dampinfo: penalty %d, flapped %d times in %s",
           penalty, bdi->flap,
	   peer_uptime (bdi->start_time, timebuf, BGP_UPTIME_LEN));

  if (CHECK_FLAG (binfo->flags, BGP_INFO_DAMPED)
      && ! CHECK_FLAG (binfo->flags, BGP_INFO_HISTORY))
    vty_out (vty, ", reuse in %s",
	     bgp_get_reuse_time (penalty, timebuf, BGP_UPTIME_LEN));

  vty_out (vty, "%s", VTY_NEWLINE);
}

char *
bgp_damp_reuse_time_vty (struct vty *vty, struct bgp_info *binfo)
{
  struct bgp_damp_info *bdi;
  time_t t_now, t_diff;
  char timebuf[BGP_UPTIME_LEN];
  int penalty;

  /* BGP dampening information.  */
  bdi = binfo->damp_info;

  /* If dampening is not enabled or there is no dampening information,
     return immediately.  */
  if (! damp || ! bdi)
    return NULL;

  /* Calculate new penalty.  */
  t_now = time (NULL);
  t_diff = t_now - bdi->t_updated;
  penalty = bgp_damp_decay (t_diff, bdi->penalty);

  return  bgp_get_reuse_time (penalty, timebuf, BGP_UPTIME_LEN);
}