/*
 *	BIRD -- The Resource Public Key Infrastructure (RPKI) to Router Protocol
 *
 *	(c) 2015 CZ.NIC
 *
 *	This file was part of RTRlib: http://rpki.realmv6.org/
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#undef LOCAL_DEBUG

#include <pthread.h>
#include <signal.h>
#include <unistd.h>

#include "rpki.h"

#include "packets.h"
#include "rtr.h"
#include "lib/timer.h"

static const char *rtr_socket_str_states[] = {
    [RTR_CONNECTING] = "RTR_CONNECTING",
    [RTR_ESTABLISHED] = "RTR_ESTABLISHED",
    [RTR_RESET] = "RTR_RESET",
    [RTR_SYNC] = "RTR_SYNC",
    [RTR_FAST_RECONNECT] = "RTR_FAST_RECONNECT",
    [RTR_ERROR_NO_DATA_AVAIL] = "RTR_ERROR_NO_DATA_AVAIL",
    [RTR_ERROR_NO_INCR_UPDATE_AVAIL] = "RTR_ERROR_NO_INCR_UPDATE_AVAIL",
    [RTR_ERROR_FATAL] = "RTR_ERROR_FATAL",
    [RTR_ERROR_TRANSPORT] = "RTR_ERROR_TRANSPORT",
    [RTR_SHUTDOWN] = "RTR_SHUTDOWN"
};

void
rtr_init(struct rtr_socket *rtr_socket, const unsigned int refresh_interval, const unsigned int expire_interval, const unsigned int retry_interval)
{
  if(refresh_interval == 0)
    rtr_socket->refresh_interval = 300;
  else if (refresh_interval > 3600)
  {
    CACHE_TRACE(D_EVENTS, rtr_socket->cache, "The refresh interval %u is too big, setting it to 3600 seconds", refresh_interval);
    rtr_socket->refresh_interval = 3600;
  }
  else
    rtr_socket->refresh_interval = (refresh_interval > (3600 - RPKI_RECV_TIMEOUT) ? (3600 - RPKI_RECV_TIMEOUT) : refresh_interval);

  rtr_socket->expire_interval = (expire_interval == 0 ? (rtr_socket->refresh_interval * 2) : expire_interval);
  rtr_socket->retry_interval = (retry_interval == 0) ? 600 : retry_interval;

  rtr_socket->state = RTR_SHUTDOWN;
  rtr_socket->request_session_id = true;
  rtr_socket->serial_number = 0;
  rtr_socket->last_update = 0;
  rtr_socket->version = RTR_PROTOCOL_MAX_SUPPORTED_VERSION;
}

void
rtr_purge_records_if_outdated(struct rpki_cache *cache)
{
  struct rtr_socket *rtr_socket = cache->rtr_socket;

  if (rtr_socket->last_update == 0)
    return;

  if ((rtr_socket->last_update + rtr_socket->expire_interval) < now)
  {
    pfx_table_src_remove(cache);
    CACHE_TRACE(D_EVENTS, cache, "Remove outdated records from pfx_table");
    rtr_socket->request_session_id = true;
    rtr_socket->serial_number = 0;
    rtr_socket->last_update = 0;
  }
  else
  {
    CACHE_DBG(cache, "There are no outdated roa records, it remains %u seconds to become obsolete", (now - (rtr_socket->last_update + rtr_socket->expire_interval)));
  }
}

void
rtr_stop(struct rtr_socket *rtr_socket)
{
  rtr_change_socket_state(rtr_socket, RTR_SHUTDOWN);
  CACHE_TRACE(D_EVENTS, rtr_socket->cache, "Socket shut down");
}

const char *
rtr_state_to_str(enum rtr_socket_state state)
{
  return rtr_socket_str_states[state];
}

/*
 * Timers
 */

void
rtr_schedule_next_refresh(struct rpki_cache *cache)
{
  struct rtr_socket *rtr_socket = cache->rtr_socket;
  struct rpki_proto *p = cache->p;

  if (cache->rtr_socket->state == RTR_SHUTDOWN)
  {
    CACHE_DBG(cache, "Stop refreshing");
    return;
  }

  unsigned time_to_wait = MAX(((int)rtr_socket->refresh_interval - (int)(now - rtr_socket->last_update)), 1);

  CACHE_DBG(cache, "Next refresh of cache(%s) will be after %u seconds", tr_ident(rtr_socket->tr_socket), time_to_wait);
  tm_start(cache->refresh_timer, time_to_wait);
}

void
rtr_schedule_next_retry(struct rpki_cache *cache)
{
  struct rtr_socket *rtr_socket = cache->rtr_socket;
  struct rpki_proto *p = cache->p;

  switch (cache->rtr_socket->state)
  {
    case RTR_ESTABLISHED:
    case RTR_SYNC:
    case RTR_RESET:
      CACHE_DBG(cache, "Stop retrying connection");
      break;

    default:
      CACHE_TRACE(D_EVENTS, cache, "Connection will retry after %u seconds again", cache->rtr_socket->retry_interval);
      tm_start(cache->retry_timer, cache->rtr_socket->retry_interval);
  }
}

void
rtr_schedule_next_expire_check(struct rpki_cache *cache)
{
  struct rtr_socket *rtr_socket = cache->rtr_socket;
  struct rpki_proto *p = cache->p;

  unsigned time_to_wait = MAX(((int)rtr_socket->expire_interval - (int)(now - rtr_socket->last_update)), 1);

  CACHE_TRACE(D_EVENTS, cache, "Next ROA expiration check will be after %u seconds again", time_to_wait);
  tm_stop(cache->expire_timer);
  tm_start(cache->expire_timer, time_to_wait);
}

void
rpki_refresh_hook(struct timer *tm)
{
  struct rpki_cache *cache = tm->data;
  struct rtr_socket *rtr_socket = cache->rtr_socket;

  switch (rtr_socket->state)
  {
    case RTR_ESTABLISHED:
      CACHE_DBG(cache, "Refreshing");
      rtr_change_socket_state(rtr_socket, RTR_SYNC);
      rtr_schedule_next_refresh(cache);
      break;

    case RTR_CONNECTING:
    case RTR_SYNC:
      /* Wait small amout of time to transite state */
      tm_start(tm, 1);
      break;

    default:
      CACHE_DBG(cache, "Stop Refreshing (%s)", rtr_socket_str_states[rtr_socket->state]);
      break;
  }
}

void
rpki_retry_hook(struct timer *tm)
{
  struct rpki_cache *cache = tm->data;
  struct rtr_socket *rtr_socket = cache->rtr_socket;
  struct rpki_proto *p = cache->p;

  switch (rtr_socket->state)
  {
    case RTR_ESTABLISHED:
    case RTR_CONNECTING:
    case RTR_SYNC:
    case RTR_SHUTDOWN:
      CACHE_DBG(cache, "Stop Retry Connecting (%s)", rtr_socket_str_states[rtr_socket->state]);
      break;

    default:
      CACHE_DBG(cache, "Retry Connecting (%s)", rtr_socket_str_states[rtr_socket->state]);
      rtr_change_socket_state(rtr_socket, RTR_CONNECTING);
      break;
  }
}

void
rpki_expire_hook(struct timer *tm)
{
  struct rpki_cache *cache = tm->data;
  struct rtr_socket *rtr_socket = cache->rtr_socket;

  if (rtr_socket->last_update == 0)
    return;

  CACHE_DBG(cache, "Expire Hook");

  rtr_purge_records_if_outdated(cache);
  rtr_schedule_next_expire_check(cache);
}