/*
 *	BIRD -- Routing Table
 *
 *	(c) 1998 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include <string.h>

#define LOCAL_DEBUG

#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "lib/resource.h"
#include "lib/event.h"
#include "conf/conf.h"
#include "filter/filter.h"

static slab *rte_slab;
static linpool *rte_update_pool;

#define RT_GC_MIN_TIME 5		/* FIXME: Make configurable */
#define RT_GC_MIN_COUNT 100

static pool *rt_table_pool;
static list routing_tables;
static event *rt_gc_event;
static bird_clock_t rt_last_gc;
static int rt_gc_counter;

static void
rte_init(struct fib_node *N)
{
  net *n = (net *) N;

  N->flags = 0;
  n->routes = NULL;
}

void
rt_setup(pool *p, rtable *t, char *name)
{
  bzero(t, sizeof(*t));
  fib_init(&t->fib, p, sizeof(net), 0, rte_init);
  t->name = name;
  init_list(&t->hooks);
}

rte *
rte_find(net *net, struct proto *p)
{
  rte *e = net->routes;

  while (e && e->attrs->proto != p)
    e = e->next;
  return e;
}

rte *
rte_get_temp(rta *a)
{
  rte *e = sl_alloc(rte_slab);

  e->attrs = a;
  e->flags = 0;
  e->pref = a->proto->preference;
  return e;
}

rte *
rte_do_cow(rte *r)
{
  rte *e = sl_alloc(rte_slab);

  memcpy(e, r, sizeof(rte));
  e->attrs = rta_clone(r->attrs);
  e->flags = 0;
  return e;
}

static int				/* Actually better or at least as good as */
rte_better(rte *new, rte *old)
{
  int (*better)(rte *, rte *);

  if (!old)
    return 1;
  if (new->pref > old->pref)
    return 1;
  if (new->pref < old->pref)
    return 0;
  if (new->attrs->proto->proto != old->attrs->proto->proto)
    bug("Different protocols, but identical preferences => oops");	/* FIXME */
  if (better = new->attrs->proto->rte_better)
    return better(new, old);
  return 0;
}

static inline void
do_rte_announce(struct announce_hook *a, net *net, rte *new, rte *old, ea_list *tmpa)
{
  struct proto *p = a->proto;
  rte *new0 = new;
  rte *old0 = old;

  if (new)
    {
      int ok = p->import_control ? p->import_control(p, &new, &tmpa, rte_update_pool) : 0;
      if (ok < 0 ||
	  (!ok && (p->out_filter == FILTER_REJECT ||
		   p->out_filter && f_run(p->out_filter, &new, &tmpa, rte_update_pool) > F_MODIFY)
	  )
	 )
	new = NULL;
    }
  if (old && p->out_filter)
    {
      /* FIXME: Do we really need to filter old routes? */
      if (p->out_filter == FILTER_REJECT)
	old = NULL;
      else
	{
	  ea_list *tmpb = p->make_tmp_attrs ? p->make_tmp_attrs(old, rte_update_pool) : NULL;
	  if (f_run(p->out_filter, &old, &tmpb, rte_update_pool) > F_MODIFY)
	    old = NULL;
	}
    }
  if (new || old)
    p->rt_notify(p, net, new, old, tmpa);
  if (new && new != new0)	/* Discard temporary rte's */
    rte_free(new);
  if (old && old != old0)
    rte_free(old);
}

static void
rte_announce(rtable *tab, net *net, rte *new, rte *old, ea_list *tmpa)
{
  struct announce_hook *a;

  WALK_LIST(a, tab->hooks)
    {
      ASSERT(a->proto->core_state == FS_HAPPY || a->proto->core_state == FS_FEEDING);
      do_rte_announce(a, net, new, old, tmpa);
    }
}

void
rt_feed_baby(struct proto *p)
{
  struct announce_hook *h;

  if (!p->ahooks)
    return;
  debug("Announcing routes to new protocol %s\n", p->name);
  for(h=p->ahooks; h; h=h->next)
    {
      rtable *t = h->table;
      FIB_WALK(&t->fib, fn)
	{
	  net *n = (net *) fn;
	  rte *e;
	  for(e=n->routes; e; e=e->next)
	    {
	      struct proto *q = e->attrs->proto;
	      ea_list *tmpa = q->make_tmp_attrs ? q->make_tmp_attrs(e, rte_update_pool) : NULL;
	      do_rte_announce(h, n, e, NULL, tmpa);
	      lp_flush(rte_update_pool);
	    }
	}
      FIB_WALK_END;
    }
}

static inline int
rte_validate(rte *e)
{
  int c;
  net *n = e->net;

  ASSERT(!ipa_nonzero(ipa_and(n->n.prefix, ipa_not(ipa_mkmask(n->n.pxlen)))));
  if (n->n.pxlen)
    {
      c = ipa_classify(n->n.prefix);
      if (c < 0 || !(c & IADDR_HOST))
	{
	  if (!ipa_nonzero(n->n.prefix) && n->n.pxlen <= 1)
	    return 1;		/* Default route and half-default route is OK */
	  log(L_WARN "Ignoring bogus route %I/%d received from %I via %s",
	      n->n.prefix, n->n.pxlen, e->attrs->from, e->attrs->proto->name);
	  return 0;
	}
      if ((c & IADDR_SCOPE_MASK) == SCOPE_HOST)
	{
	  int s = e->attrs->source;
	  if (s != RTS_STATIC && s != RTS_DEVICE && s != RTS_STATIC_DEVICE)
	    {
	      log(L_WARN "Ignoring host scope route %I/%d received from %I via %s",
		  n->n.prefix, n->n.pxlen, e->attrs->from, e->attrs->proto->name);
	      return 0;
	    }
	}
    }
  return 1;
}

void
rte_free(rte *e)
{
  if (e->attrs->aflags & RTAF_CACHED)
    rta_free(e->attrs);
  sl_free(rte_slab, e);
}

static inline void
rte_free_quick(rte *e)
{
  rta_free(e->attrs);
  sl_free(rte_slab, e);
}

static void
rte_recalculate(rtable *table, net *net, struct proto *p, rte *new, ea_list *tmpa)
{
  rte *old_best = net->routes;
  rte *old = NULL;
  rte **k, *r, *s;

  k = &net->routes;			/* Find and remove original route from the same protocol */
  while (old = *k)
    {
      if (old->attrs->proto == p)
	{
	  *k = old->next;
	  break;
	}
      k = &old->next;
    }

  if (new && rte_better(new, old_best))	/* It's a new optimal route => announce and relink it */
    {
      rte_announce(table, net, new, old_best, tmpa);
      new->next = net->routes;
      net->routes = new;
    }
  else
    {
      if (old == old_best)		/* It has _replaced_ the old optimal route */
	{
	  r = new;			/* Find new optimal route and announce it */
	  for(s=net->routes; s; s=s->next)
	    if (rte_better(s, r))
	      r = s;
	  rte_announce(table, net, r, old_best, tmpa);
	  if (r)			/* Re-link the new optimal route */
	    {
	      k = &net->routes;
	      while (s = *k)
		{
		  if (s == r)
		    {
		      *k = r->next;
		      break;
		    }
		  k = &s->next;
		}
	      r->next = net->routes;
	      net->routes = r;
	      if (!r && rt_gc_counter++ >= RT_GC_MIN_COUNT && rt_last_gc + RT_GC_MIN_TIME <= now)
		ev_schedule(rt_gc_event);
	    }
	}
      if (new)				/* Link in the new non-optimal route */
	{
	  new->next = old_best->next;
	  old_best->next = new;
	}
    }
  if (old)
    {
      if (p->rte_remove)
	p->rte_remove(net, old);
      rte_free_quick(old);
    }
  if (new)
    {
      new->lastmod = now;
      if (p->rte_insert)
	p->rte_insert(net, new);
    }
}

static int rte_update_nest_cnt;		/* Nesting counter to allow recursive updates */

static inline void
rte_update_lock(void)
{
  rte_update_nest_cnt++;
}

static inline void
rte_update_unlock(void)
{
  if (!--rte_update_nest_cnt)
    lp_flush(rte_update_pool);
}

void
rte_update(rtable *table, net *net, struct proto *p, rte *new)
{
  ea_list *tmpa = NULL;

  rte_update_lock();
  if (new)
    {
      if (!rte_validate(new) || p->in_filter == FILTER_REJECT)
	goto drop;
      if (p->make_tmp_attrs)
	tmpa = p->make_tmp_attrs(new, rte_update_pool);
      if (p->in_filter)
	{
	  int fr = f_run(p->in_filter, &new, &tmpa, rte_update_pool);
	  if (fr > F_MODIFY)
	    goto drop;
	  if (fr == F_MODIFY && p->store_tmp_attrs)
	    p->store_tmp_attrs(new, tmpa);
	}
      if (!(new->attrs->aflags & RTAF_CACHED)) /* Need to copy attributes */
	new->attrs = rta_lookup(new->attrs);
      new->flags |= REF_COW;
    }
  rte_recalculate(table, net, p, new, tmpa);
  rte_update_unlock();
  return;

drop:
  rte_free(new);
  rte_update_unlock();
}

void
rte_discard(rtable *t, rte *old)	/* Non-filtered route deletion, used during garbage collection */
{
  rte_update_lock();
  rte_recalculate(t, old->net, old->attrs->proto, NULL, NULL);
  rte_update_unlock();
}

void
rte_dump(rte *e)
{
  net *n = e->net;
  if (n)
    debug("%1I/%2d ", n->n.prefix, n->n.pxlen);
  else
    debug("??? ");
  debug("KF=%02x PF=%02x pref=%d lm=%d ", n->n.flags, e->pflags, e->pref, now-e->lastmod);
  rta_dump(e->attrs);
  if (e->attrs->proto->proto->dump_attrs)
    e->attrs->proto->proto->dump_attrs(e);
  debug("\n");
}

void
rt_dump(rtable *t)
{
  rte *e;
  net *n;
  struct announce_hook *a;

  debug("Dump of routing table <%s>\n", t->name);
#ifdef DEBUGGING
  fib_check(&t->fib);
#endif
  FIB_WALK(&t->fib, fn)
    {
      n = (net *) fn;
      for(e=n->routes; e; e=e->next)
	rte_dump(e);
    }
  FIB_WALK_END;
  WALK_LIST(a, t->hooks)
    debug("\tAnnounces routes to protocol %s\n", a->proto->name);
  debug("\n");
}

void
rt_dump_all(void)
{
  rtable *t;

  WALK_LIST(t, routing_tables)
    rt_dump(t);
}

static void
rt_gc(void *unused)
{
  rtable *t;

  DBG("Entered routing table garbage collector after %d seconds and %d deletes\n", (int)(now - rt_last_gc), rt_gc_counter);
  rt_prune_all();
  rt_last_gc = now;
  rt_gc_counter = 0;
}

void
rt_init(void)
{
  rta_init();
  rt_table_pool = rp_new(&root_pool, "Routing tables");
  rte_update_pool = lp_new(rt_table_pool, 4080);
  rte_slab = sl_new(rt_table_pool, sizeof(rte));
  rt_last_gc = now;
  rt_gc_event = ev_new(rt_table_pool);
  rt_gc_event->hook = rt_gc;
  init_list(&routing_tables);
}

void
rt_prune(rtable *tab)
{
  struct fib_iterator fit;
  int rcnt = 0, rdel = 0, ncnt = 0, ndel = 0;

  DBG("Pruning route table %s\n", tab->name);
  FIB_ITERATE_INIT(&fit, &tab->fib);
again:
  FIB_ITERATE_START(&tab->fib, &fit, f)
    {
      net *n = (net *) f;
      rte *e;
      ncnt++;
    rescan:
      for (e=n->routes; e; e=e->next, rcnt++)
	if (e->attrs->proto->core_state != FS_HAPPY)
	  {
	    rte_discard(tab, e);
	    rdel++;
	    goto rescan;
	  }
      if (!n->routes)		/* Orphaned FIB entry? */
	{
	  FIB_ITERATE_PUT(&fit, f);
	  fib_delete(&tab->fib, f);
	  ndel++;
	  goto again;
	}
    }
  FIB_ITERATE_END(f);
  DBG("Pruned %d of %d routes and %d of %d networks\n", rcnt, rdel, ncnt, ndel);
}

void
rt_prune_all(void)
{
  rtable *t;

  WALK_LIST(t, routing_tables)
    rt_prune(t);
}

void
rt_preconfig(struct config *c)
{
  struct symbol *s = cf_find_symbol("master");
  struct rtable_config *r = cfg_allocz(sizeof(struct rtable_config));

  cf_define_symbol(s, SYM_TABLE, r);
  r->name = s->name;
  init_list(&c->tables);
  add_tail(&c->tables, &r->n);
  c->master_rtc = r;
}

void
rt_commit(struct config *c)
{
  struct rtable_config *r;

  WALK_LIST(r, c->tables)
    {
      rtable *t = mb_alloc(rt_table_pool, sizeof(struct rtable));
      rt_setup(rt_table_pool, t, r->name);
      add_tail(&routing_tables, &t->n);
      r->table = t;
    }
}