ospf_nsm.c

router source code for the ospdf.

  if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL)
    {
      struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;

      nbr_nbma->nbr = NULL;
      nbr_nbma->state_change = nbr->state_change;

      nbr->nbr_nbma = NULL;

      OSPF_POLL_TIMER_ON (nbr_nbma->t_poll, ospf_poll_timer,
			  nbr_nbma->v_poll);

      if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
	zlog_info ("NSM[%s:%s]: Down (PollIntervalTimer scheduled)",
		   IF_NAME (nbr->oi), inet_ntoa (nbr->address.u.prefix4));  
    }

  /* Delete neighbor from interface. */
  ospf_nbr_delete (nbr);

  return 0;
}

int
nsm_inactivity_timer (struct ospf_neighbor *nbr)
{
  /* Kill neighbor. */
  nsm_kill_nbr (nbr);

  return 0;
}

int
nsm_ll_down (struct ospf_neighbor *nbr)
{
  /* Reset neighbor. */
  /*nsm_reset_nbr (nbr);*/
  
  /* Kill neighbor. */
  nsm_kill_nbr (nbr);

  return 0;
}

/* Neighbor State Machine */
struct {
  int (*func) ();
  int next_state;
} NSM [OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] =
{
  {
    /* DependUpon: dummy state. */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_ignore,              NSM_DependUpon }, /* HelloReceived     */
    { nsm_ignore,              NSM_DependUpon }, /* Start             */
    { nsm_ignore,              NSM_DependUpon }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_DependUpon }, /* NegotiationDone   */
    { nsm_ignore,              NSM_DependUpon }, /* ExchangeDone      */
    { nsm_ignore,              NSM_DependUpon }, /* BadLSReq          */
    { nsm_ignore,              NSM_DependUpon }, /* LoadingDone       */
    { nsm_ignore,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_ignore,              NSM_DependUpon }, /* SeqNumberMismatch */
    { nsm_ignore,              NSM_DependUpon }, /* 1-WayReceived     */
    { nsm_ignore,              NSM_DependUpon }, /* KillNbr           */
    { nsm_ignore,              NSM_DependUpon }, /* InactivityTimer   */
    { nsm_ignore,              NSM_DependUpon }, /* LLDown            */
  },
  {
    /* Down: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
    { nsm_start,               NSM_Attempt    }, /* Start             */
    { nsm_ignore,              NSM_Down       }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Down       }, /* NegotiationDone   */
    { nsm_ignore,              NSM_Down       }, /* ExchangeDone      */
    { nsm_ignore,              NSM_Down       }, /* BadLSReq          */
    { nsm_ignore,              NSM_Down       }, /* LoadingDone       */
    { nsm_ignore,              NSM_Down       }, /* AdjOK?            */
    { nsm_ignore,              NSM_Down       }, /* SeqNumberMismatch */
    { nsm_ignore,              NSM_Down       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* Attempt: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
    { nsm_ignore,              NSM_Attempt    }, /* Start             */
    { nsm_ignore,              NSM_Attempt    }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Attempt    }, /* NegotiationDone   */
    { nsm_ignore,              NSM_Attempt    }, /* ExchangeDone      */
    { nsm_ignore,              NSM_Attempt    }, /* BadLSReq          */
    { nsm_ignore,              NSM_Attempt    }, /* LoadingDone       */
    { nsm_ignore,              NSM_Attempt    }, /* AdjOK?            */
    { nsm_ignore,              NSM_Attempt    }, /* SeqNumberMismatch */
    { nsm_ignore,              NSM_Attempt    }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* Init: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
    { nsm_ignore,              NSM_Init       }, /* Start             */
    { nsm_twoway_received,     NSM_DependUpon }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Init       }, /* NegotiationDone   */
    { nsm_ignore,              NSM_Init       }, /* ExchangeDone      */
    { nsm_ignore,              NSM_Init       }, /* BadLSReq          */
    { nsm_ignore,              NSM_Init       }, /* LoadingDone       */
    { nsm_ignore,              NSM_Init       }, /* AdjOK?            */
    { nsm_ignore,              NSM_Init       }, /* SeqNumberMismatch */
    { nsm_ignore,              NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* 2-Way: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_TwoWay     }, /* HelloReceived     */
    { nsm_ignore,              NSM_TwoWay     }, /* Start             */
    { nsm_ignore,              NSM_TwoWay     }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_TwoWay     }, /* NegotiationDone   */
    { nsm_ignore,              NSM_TwoWay     }, /* ExchangeDone      */
    { nsm_ignore,              NSM_TwoWay     }, /* BadLSReq          */
    { nsm_ignore,              NSM_TwoWay     }, /* LoadingDone       */
    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_ignore,              NSM_TwoWay     }, /* SeqNumberMismatch */
    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* ExStart: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_ExStart    }, /* HelloReceived     */
    { nsm_ignore,              NSM_ExStart    }, /* Start             */
    { nsm_ignore,              NSM_ExStart    }, /* 2-WayReceived     */
    { nsm_negotiation_done,    NSM_Exchange   }, /* NegotiationDone   */
    { nsm_ignore,              NSM_ExStart    }, /* ExchangeDone      */
    { nsm_ignore,              NSM_ExStart    }, /* BadLSReq          */
    { nsm_ignore,              NSM_ExStart    }, /* LoadingDone       */
    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_ignore,              NSM_ExStart    }, /* SeqNumberMismatch */
    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* Exchange: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Exchange   }, /* HelloReceived     */
    { nsm_ignore,              NSM_Exchange   }, /* Start             */
    { nsm_ignore,              NSM_Exchange   }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Exchange   }, /* NegotiationDone   */
    { nsm_exchange_done,       NSM_DependUpon }, /* ExchangeDone      */
    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
    { nsm_ignore,              NSM_Exchange   }, /* LoadingDone       */
    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  {
    /* Loading: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Loading    }, /* HelloReceived     */
    { nsm_ignore,              NSM_Loading    }, /* Start             */
    { nsm_ignore,              NSM_Loading    }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Loading    }, /* NegotiationDone   */
    { nsm_ignore,              NSM_Loading    }, /* ExchangeDone      */
    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
    { nsm_ignore,              NSM_Full       }, /* LoadingDone       */
    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
  { /* Full: */
    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
    { nsm_hello_received,      NSM_Full       }, /* HelloReceived     */
    { nsm_ignore,              NSM_Full       }, /* Start             */
    { nsm_ignore,              NSM_Full       }, /* 2-WayReceived     */
    { nsm_ignore,              NSM_Full       }, /* NegotiationDone   */
    { nsm_ignore,              NSM_Full       }, /* ExchangeDone      */
    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
    { nsm_ignore,              NSM_Full       }, /* LoadingDone       */
    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
  },
};

static char *ospf_nsm_event_str[] =
{
  "NoEvent",
  "HelloReceived",
  "Start",
  "2-WayReceived",
  "NegotiationDone",
  "ExchangeDone",
  "BadLSReq",
  "LoadingDone",
  "AdjOK?",
  "SeqNumberMismatch",
  "1-WayReceived",
  "KillNbr",
  "InactivityTimer",
  "LLDown",
};

void
nsm_change_state (struct ospf_neighbor *nbr, int state)
{
  struct ospf_interface *oi = nbr->oi;
  struct ospf_area *vl_area = NULL;
  u_char old_state;
  int x;
  int force = 1;
  
  /* Logging change of status. */
  if (IS_DEBUG_OSPF (nsm, NSM_STATUS))
    zlog_info ("NSM[%s:%s]: State change %s -> %s",
	       IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
	       LOOKUP (ospf_nsm_state_msg, nbr->state),
	       LOOKUP (ospf_nsm_state_msg, state));

  /* Preserve old status. */
  old_state = nbr->state;

  /* Change to new status. */
  nbr->state = state;

  /* Statistics. */
  nbr->state_change++;

  if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
    vl_area = ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
  
  /* One of the neighboring routers changes to/from the FULL state. */
  if ((old_state != NSM_Full && state == NSM_Full) ||
      (old_state == NSM_Full && state != NSM_Full))
    { 
      if (state == NSM_Full)
	{
	  oi->full_nbrs++;
	  oi->area->full_nbrs++;

          ospf_check_abr_status (oi->ospf);

	  if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
            if (++vl_area->full_vls == 1)
	      ospf_schedule_abr_task (oi->ospf);

	  /* kevinm: refresh any redistributions */
	  for (x = ZEBRA_ROUTE_SYSTEM; x < ZEBRA_ROUTE_MAX; x++)
	    {
	      if (x == ZEBRA_ROUTE_OSPF || x == ZEBRA_ROUTE_OSPF6)
		continue;
	      ospf_external_lsa_refresh_type (oi->ospf, x, force);
	    }
	}
      else
	{
	  oi->full_nbrs--;
	  oi->area->full_nbrs--;

          ospf_check_abr_status (oi->ospf);

	  if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
	    if (vl_area->full_vls > 0)
	      if (--vl_area->full_vls == 0)
		ospf_schedule_abr_task (oi->ospf);
 
          /* clear neighbor retransmit list */
          if (!ospf_ls_retransmit_isempty (nbr))
            ospf_ls_retransmit_clear (nbr);
	}

      zlog_info ("nsm_change_state(): "
		 "scheduling new router-LSA origination");

      ospf_router_lsa_timer_add (oi->area);

      if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
	{
	  struct ospf_area *vl_area =
	    ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
	  
	  if (vl_area)
	    ospf_router_lsa_timer_add (vl_area);
	}

      /* Originate network-LSA. */
      if (oi->state == ISM_DR)
	{
	  if (oi->network_lsa_self && oi->full_nbrs == 0)
	    {
	      ospf_lsa_flush_area (oi->network_lsa_self, oi->area);
	      ospf_lsa_unlock (oi->network_lsa_self);
	      oi->network_lsa_self = NULL;
	      OSPF_TIMER_OFF (oi->t_network_lsa_self);
	    }
	  else
	    ospf_network_lsa_timer_add (oi);
	}
    }

#ifdef HAVE_OPAQUE_LSA
  ospf_opaque_nsm_change (nbr, old_state);
#endif /* HAVE_OPAQUE_LSA */

  /* Start DD exchange protocol */
  if (state == NSM_ExStart)
    {
      if (nbr->dd_seqnum == 0)
	nbr->dd_seqnum = time (NULL);
      else
	nbr->dd_seqnum++;

      nbr->dd_flags = OSPF_DD_FLAG_I|OSPF_DD_FLAG_M|OSPF_DD_FLAG_MS;
      ospf_db_desc_send (nbr);
    }

  /* clear cryptographic sequence number */
  if (state == NSM_Down)
    nbr->crypt_seqnum = 0;
  
  /* Generete NeighborChange ISM event. */
#ifdef BUGGY_ISM_TRANSITION
  if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
      (old_state >= NSM_TwoWay && state < NSM_TwoWay))
    OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
#else /* BUGGY_ISM_TRANSITION */
  switch (oi->state) {
  case ISM_DROther:
  case ISM_Backup:
  case ISM_DR:
    if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
        (old_state >= NSM_TwoWay && state < NSM_TwoWay))
      OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
    break;
  default:
    /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc. */
    break;
  }
#endif /* BUGGY_ISM_TRANSITION */

  /* Performance hack. Send hello immideately when some neighbor enter
     Init state.  This whay we decrease neighbor discovery time. Gleb.*/
  if (state == NSM_Init)
    {
      OSPF_ISM_TIMER_OFF (oi->t_hello);
      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
    }

  /* Preserve old status? */
}

/* Execute NSM event process. */
int
ospf_nsm_event (struct thread *thread)
{
  int event;
  int next_state;
  struct ospf_neighbor *nbr;
  struct in_addr router_id;
  int old_state;
  struct ospf_interface *oi;

  nbr = THREAD_ARG (thread);
  event = THREAD_VAL (thread);
  router_id = nbr->router_id;

  old_state = nbr->state;
  oi = nbr->oi ;
  
  /* Call function. */
  next_state = (*(NSM [nbr->state][event].func))(nbr);

  /* When event is NSM_KillNbr or InactivityTimer, the neighbor is
     deleted. */
  if (event == NSM_KillNbr || event == NSM_InactivityTimer)
    {
      if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
	zlog_info ("NSM[%s:%s]: neighbor deleted",
		   IF_NAME (oi), inet_ntoa (router_id));

      /* Timers are canceled in ospf_nbr_free, moreover we cannot call
         nsm_timer_set here because nbr is freed already!!!*/
      /*nsm_timer_set (nbr);*/

      return 0;
    }

  if (! next_state)
    next_state = NSM [nbr->state][event].next_state;

  if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
    zlog_info ("NSM[%s:%s]: %s (%s)", IF_NAME (oi),
	       inet_ntoa (nbr->router_id),
	       LOOKUP (ospf_nsm_state_msg, nbr->state),
	       ospf_nsm_event_str [event]);
  
  /* If state is changed. */
  if (next_state != nbr->state)
    nsm_change_state (nbr, next_state);

  /* Make sure timer is set. */
  nsm_timer_set (nbr);

  return 0;
}

/* Check loading state. */
void
ospf_check_nbr_loading (struct ospf_neighbor *nbr)
{
  if (nbr->state == NSM_Loading)
    {
      if (ospf_ls_request_isempty (nbr))
	OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_LoadingDone);
      else if (nbr->ls_req_last == NULL)
	ospf_ls_req_event (nbr);
    }
}