/*
 *	BIRD -- Direct Device Routes
 *
 *	(c) 1998--2000 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

/**
 * DOC: Direct
 *
 * The Direct protocol works by converting all ifa_notify() events it receives
 * to rte_update() calls for the corresponding network.
 */

#undef LOCAL_DEBUG

#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/rt.h"
#include "nest/rt-dev.h"
#include "conf/conf.h"
#include "lib/resource.h"
#include "lib/string.h"


static void
dev_ifa_notify(struct proto *P, uint flags, struct ifa *ad)
{
  struct rt_dev_proto *p = (void *) P;
  struct rt_dev_config *cf = (void *) P->cf;
  struct channel *c;
  net_addr *net = &ad->prefix;

  if (!EMPTY_LIST(cf->iface_list) &&
      !iface_patt_find(&cf->iface_list, ad->iface, ad))
    /* Empty list is automatically treated as "*" */
    return;

  if (ad->flags & IA_SECONDARY)
    return;

  if (ad->scope <= SCOPE_LINK)
    return;

  if (ad->prefix.type == NET_IP4)
    c = p->ip4_channel;
  else if (ad->prefix.type == NET_IP6)
    c = p->ip6_channel;
  else
    return;

  if (!c)
    return;

  /* For IPv6 SADR, replace regular prefix with SADR prefix */
  if (c->net_type == NET_IP6_SADR)
  {
    net = alloca(sizeof(net_addr_ip6_sadr));
    net_fill_ip6_sadr(net, net6_prefix(&ad->prefix), net6_pxlen(&ad->prefix), IP6_NONE, 0);
  }

  if (flags & IF_CHANGE_DOWN)
    {
      DBG("dev_if_notify: %s:%I going down\n", ad->iface->name, ad->ip);

      /* Use iface ID as local source ID */
      struct rte_src *src = rt_get_source(P, ad->iface->index);
      rte_update(c, net, NULL, src);
    }
  else if (flags & IF_CHANGE_UP)
    {
      DBG("dev_if_notify: %s:%I going up\n", ad->iface->name, ad->ip);

      if (cf->check_link && !(ad->iface->flags & IF_LINK_UP))
	return;

      /* Use iface ID as local source ID */
      struct rte_src *src = rt_get_source(P, ad->iface->index);

      rta a0 = {
	.dest = RTD_UNICAST,
      };

      struct nexthop_adata nhad = {
	.nh = { .iface = ad->iface, },
	.ad = { .length = (void *) NEXTHOP_NEXT(&nhad.nh) - (void *) nhad.ad.data, },
      };

      ea_set_attr_u32(&a0.eattrs, &ea_gen_preference, 0, c->preference);
      ea_set_attr_u32(&a0.eattrs, &ea_gen_source, 0, RTS_DEVICE);
      ea_set_attr_data(&a0.eattrs, &ea_gen_nexthop, 0, nhad.ad.data, nhad.ad.length);

      rte e0 = {
	.attrs = rta_lookup(&a0),
	.src = src,
      };

      rte_update(c, net, &e0, src);
    }
}

static void
dev_if_notify(struct proto *p, uint c, struct iface *iface)
{
  struct rt_dev_config *cf = (void *) p->cf;

  if (c & (IF_CHANGE_UP | IF_CHANGE_DOWN))
    return;

  if ((c & IF_CHANGE_LINK) && cf->check_link)
  {
    uint ac = (iface->flags & IF_LINK_UP) ? IF_CHANGE_UP : IF_CHANGE_DOWN;

    struct ifa *a;
    WALK_LIST(a, iface->addrs)
      dev_ifa_notify(p, ac, a);
  }
}

static void
dev_postconfig(struct proto_config *CF)
{
  struct rt_dev_config *cf = (void *) CF;
  struct channel_config *ip4, *ip6, *ip6_sadr;

  ip4 = proto_cf_find_channel(CF, NET_IP4);
  ip6 = proto_cf_find_channel(CF, NET_IP6);
  ip6_sadr = proto_cf_find_channel(CF, NET_IP6_SADR);

  if (ip6 && ip6_sadr)
    cf_error("Both ipv6 and ipv6-sadr channels");

  cf->ip4_channel = ip4;
  cf->ip6_channel = ip6 ?: ip6_sadr;
}

static struct proto *
dev_init(struct proto_config *CF)
{
  struct proto *P = proto_new(CF);
  struct rt_dev_proto *p = (void *) P;
  struct rt_dev_config *cf = (void *) CF;

  proto_configure_channel(P, &p->ip4_channel, cf->ip4_channel);
  proto_configure_channel(P, &p->ip6_channel, cf->ip6_channel);

  P->if_notify = dev_if_notify;
  P->ifa_notify = dev_ifa_notify;

  return P;
}

static int
dev_reconfigure(struct proto *P, struct proto_config *CF)
{
  struct rt_dev_proto *p = (void *) P;
  struct rt_dev_config *o = (void *) P->cf;
  struct rt_dev_config *n = (void *) CF;

  if (!iface_patts_equal(&o->iface_list, &n->iface_list, NULL) ||
      (o->check_link != n->check_link))
    return 0;

  return
    proto_configure_channel(P, &p->ip4_channel, n->ip4_channel) &&
    proto_configure_channel(P, &p->ip6_channel, n->ip6_channel);

  return 1;
}

static void
dev_copy_config(struct proto_config *dest, struct proto_config *src)
{
  struct rt_dev_config *d = (void *) dest;
  struct rt_dev_config *s = (void *) src;

  /*
   * We copy iface_list as ifaces can be shared by more direct protocols.
   * Copy suffices to be is shallow, because new nodes can be added, but
   * old nodes cannot be modified (although they contain internal lists).
   */
  cfg_copy_list(&d->iface_list, &s->iface_list, sizeof(struct iface_patt));

  d->check_link = s->check_link;
}

struct protocol proto_device = {
  .name =		"Direct",
  .template =		"direct%d",
  .preference =		DEF_PREF_DIRECT,
  .channel_mask =	NB_IP | NB_IP6_SADR,
  .proto_size =		sizeof(struct rt_dev_proto),
  .config_size =	sizeof(struct rt_dev_config),
  .postconfig =		dev_postconfig,
  .init =		dev_init,
  .reconfigure =	dev_reconfigure,
  .copy_config =	dev_copy_config
};

void
dev_build(void)
{
  proto_build(&proto_device);
}