/*
 *	BIRD -- Protocols
 *
 *	(c) 1998--1999 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#define LOCAL_DEBUG

#include <string.h>

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

static pool *proto_pool;

list protocol_list;
list proto_list;

static list inactive_proto_list;
static list initial_proto_list;

static char *p_states[] = { "DOWN", "START", "UP", "STOP" };
static char *c_states[] = { "HUNGRY", "FEEDING", "HAPPY", "FLUSHING" };

static void
proto_relink(struct proto *p)
{
  rem_node(&p->n);
  add_tail(p->core_state == FS_HAPPY ? &proto_list : &inactive_proto_list, &p->n);
}

void *
proto_new(struct proto_config *c, unsigned size)
{
  struct protocol *pr = c->proto;
  pool *r = rp_new(proto_pool, c->name);
  struct proto *p = mb_alloc(r, size);

  p->cf = c;
  p->debug = c->debug;
  p->name = c->name;
  p->preference = c->preference;
  p->disabled = c->disabled;
  p->proto = pr;
  p->pool = r;
  p->attn = ev_new(r);
  p->attn->data = p;
  return p;
}

void *
proto_config_new(struct protocol *pr, unsigned size)
{
  struct proto_config *c = cfg_allocz(size);

  add_tail(&new_config->protos, &c->n);
  c->global = new_config;
  c->proto = pr;
  c->debug = pr->debug;
  c->name = pr->name;
  return c;
}

void
protos_preconfig(struct config *c)
{
  struct protocol *p;

  init_list(&proto_list);
  init_list(&inactive_proto_list);
  init_list(&initial_proto_list);
  debug("Protocol preconfig:");
  WALK_LIST(p, protocol_list)
    {
      debug(" %s", p->name);
      if (p->preconfig)
	p->preconfig(p, c);
    }
  debug("\n");
}

void
protos_postconfig(struct config *c)
{
  struct proto_config *x;
  struct protocol *p;

  debug("Protocol postconfig:");
  WALK_LIST(x, c->protos)
    {
      debug(" %s", x->name);
      p = x->proto;
      if (p->postconfig)
	p->postconfig(x);
    }
  debug("\n");
}

void
protos_commit(struct config *c)
{
  struct proto_config *x;
  struct protocol *p;
  struct proto *q;

  debug("Protocol commit:");
  WALK_LIST(x, c->protos)
    {
      debug(" %s", x->name);
      p = x->proto;
      q = p->init(x);
      q->proto_state = PS_DOWN;
      q->core_state = FS_HUNGRY;
      add_tail(&initial_proto_list, &q->n);
    }
  debug("\n");
}

static void
proto_rethink_goal(struct proto *p)
{
  struct protocol *q = p->proto;

  if (p->core_state == p->core_goal)
    return;
  if (p->core_goal == FS_HAPPY)		/* Going up */
    {
      if (p->core_state == FS_HUNGRY && p->proto_state == PS_DOWN)
	{
	  DBG("Kicking %s up\n", p->name);
	  proto_notify_state(p, (q->start ? q->start(p) : PS_UP));
	}
    }
  else 					/* Going down */
    {
      if (p->proto_state == PS_START || p->proto_state == PS_UP)
	{
	  DBG("Kicking %s down\n", p->name);
	  proto_notify_state(p, (q->shutdown ? q->shutdown(p) : PS_DOWN));
	}
    }
}

static void
proto_set_goal(struct proto *p, unsigned goal)
{
  if (p->disabled)
    goal = FS_HUNGRY;
  p->core_goal = goal;
  proto_rethink_goal(p);
}

void
protos_start(void)
{
  struct proto *p, *n;

  debug("Protocol start\n");
  WALK_LIST_DELSAFE(p, n, initial_proto_list)
    proto_set_goal(p, FS_HAPPY);
}

void
protos_dump_all(void)
{
  struct proto *p;

  debug("Protocols:\n");

  WALK_LIST(p, proto_list)
    {
      debug("  protocol %s: state %s/%s\n", p->name, p_states[p->proto_state], c_states[p->core_state]);
      if (p->disabled)
	debug("\tDISABLED\n");
      else if (p->proto->dump)
	p->proto->dump(p);
    }
  WALK_LIST(p, inactive_proto_list)
    debug("  inactive %s: state %s/%s\n", p->name, p_states[p->proto_state], c_states[p->core_state]);
  WALK_LIST(p, initial_proto_list)
    debug("  initial %s\n", p->name);
}

void
protos_build(void)
{
  init_list(&protocol_list);
  add_tail(&protocol_list, &proto_device.n);
#ifdef CONFIG_RIP
  add_tail(&protocol_list, &proto_rip.n);
#endif
#ifdef CONFIG_STATIC
  add_tail(&protocol_list, &proto_static.n);
#endif
  proto_pool = rp_new(&root_pool, "Protocols");
}

static void
proto_fell_down(struct proto *p)
{
  DBG("Protocol %s down\n", p->name);
  proto_rethink_goal(p);
}

static void
proto_feed(void *P)
{
  struct proto *p = P;

  DBG("Feeding protocol %s\n", p->name);
  if_feed_baby(p);
  rt_feed_baby(p);
  p->core_state = FS_HAPPY;
  proto_relink(p);
  DBG("Protocol %s up and running\n", p->name);
}

static void
proto_flush(void *P)
{
  struct proto *p = P;

  DBG("Flushing protocol %s\n", p->name);
  bug("Protocol flushing not supported yet!"); /* FIXME */
}

void
proto_notify_state(struct proto *p, unsigned ps)
{
  unsigned ops = p->proto_state;
  unsigned cs = p->core_state;

  DBG("%s reporting state transition %s/%s -> */%s\n", p->name, c_states[cs], p_states[ops], p_states[ps]);
  if (ops == ps)
    return;

  switch (ps)
    {
    case PS_DOWN:
      if (cs == FS_HUNGRY)		/* Shutdown finished */
	proto_fell_down(p);
      else if (cs == FS_FLUSHING)	/* Still flushing... */
	;
      else				/* Need to start flushing */
	goto schedule_flush;
      break;
    case PS_START:
      ASSERT(ops == PS_DOWN);
      ASSERT(cs == FS_HUNGRY);
      break;
    case PS_UP:
      ASSERT(ops == PS_DOWN || ops == PS_START);
      ASSERT(cs == FS_HUNGRY);
      DBG("%s: Scheduling meal\n", p->name);
      cs = FS_FEEDING;
      p->attn->hook = proto_feed;
      ev_schedule(p->attn);
      break;
    case PS_STOP:
      if (cs == FS_FEEDING || cs == FS_HAPPY)
	{
	schedule_flush:
	  DBG("%s: Scheduling flush\n", p->name);
	  cs = FS_FLUSHING;
	  p->attn->hook = proto_flush;
	  ev_schedule(p->attn);
	}
    default:
    error:
      bug("Invalid state transition for %s from %s/%s to */%s", p->name, c_states[cs], p_states[ops], p_states[ps]);
    }
  p->proto_state = ps;
  p->core_state = cs;
  proto_relink(p);
}