/*
 * VRF functions.
 * Copyright (C) 2014 6WIND S.A.
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Zebra; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <zebra.h>

#include "if.h"
#include "vrf.h"
#include "prefix.h"
#include "table.h"
#include "log.h"
#include "memory.h"
#include "command.h"

/*
 * Turn on/off debug code
 * for vrf.
 */
int debug_vrf = 0;

/* Holding VRF hooks  */
struct vrf_master
{
  int (*vrf_new_hook) (vrf_id_t, const char *, void **);
  int (*vrf_delete_hook) (vrf_id_t, const char *, void **);
  int (*vrf_enable_hook) (vrf_id_t, const char *, void **);
  int (*vrf_disable_hook) (vrf_id_t, const char *, void **);
} vrf_master = {0,};

/* VRF table */
struct route_table *vrf_table = NULL;

/* VRF is part of a list too to store it before its actually active */
struct list *vrf_list;

static int vrf_is_enabled (struct vrf *vrf);
static void vrf_disable (struct vrf *vrf);

/* VRF list existance check by name. */
struct vrf *
vrf_list_lookup_by_name (const char *name)
{
  struct listnode *node;
  struct vrf *vrfp;

  if (name)
    for (ALL_LIST_ELEMENTS_RO (vrf_list, node, vrfp))
      {
        if (strcmp(name, vrfp->name) == 0)
          return vrfp;
      }
  return NULL;
}

/* Create new vrf structure. */
struct vrf *
vrf_create (const char *name, size_t namelen)
{
  struct vrf *vrfp;

  vrfp = XCALLOC (MTYPE_VRF, sizeof (struct vrf));

  assert (name);
  assert (namelen <= VRF_NAMSIZ);	/* Need space for '\0' at end. */
  strncpy (vrfp->name, name, namelen);
  vrfp->name[namelen] = '\0';
  if (vrf_list_lookup_by_name (vrfp->name) == NULL)
    listnode_add_sort (vrf_list, vrfp);
  else
    zlog_err("vrf_create(%s): corruption detected -- vrf with this "
             "name exists already with vrf-id %u!", vrfp->name, vrfp->vrf_id);

  UNSET_FLAG(vrfp->status, VRF_ACTIVE);

  if (vrf_master.vrf_new_hook)
    (*vrf_master.vrf_new_hook) (0, name, &vrfp->info);

  return vrfp;
}

struct vrf *
vrf_get_by_name (const char *name)
{
  struct vrf *vrfp;

  return ((vrfp = vrf_list_lookup_by_name (name)) != NULL) ? vrfp :
          vrf_create (name, strlen(name));
}

/* Build the table key */
static void
vrf_build_key (vrf_id_t vrf_id, struct prefix *p)
{
  p->family = AF_INET;
  p->prefixlen = IPV4_MAX_BITLEN;
  p->u.prefix4.s_addr = vrf_id;
}

/* Get a VRF. If not found, create one.
 * Arg: name
 * Description: Please note that this routine can be called with just the name
   and 0 vrf-id */
struct vrf *
vrf_get (vrf_id_t vrf_id, const char *name)
{
  struct prefix p;
  struct route_node *rn;
  struct vrf *vrf = NULL;
  size_t namelen = 0;

  vrf_build_key (vrf_id, &p);
  rn = route_node_get (vrf_table, &p);
  if (rn->info)
    {
      vrf = (struct vrf *)rn->info;
      route_unlock_node (rn); /* get */

      if (name)
        {
          strncpy (vrf->name, name, strlen(name));
          vrf->name[strlen(name)] = '\0';
          if (vrf_list_lookup_by_name (vrf->name) == NULL)
            listnode_add_sort (vrf_list, vrf);
        }
      if (debug_vrf)
	zlog_debug ("VRF(%u) %s Found %p", vrf_id, (name) ? name : "(NULL)",
		    vrf);
    }
  else
    {
      if (name)
        vrf = vrf_list_lookup_by_name(name);

      if (vrf)
	{
	  if (debug_vrf)
	    zlog_debug ("VRF(%u) %s lookup by name is successful",
			vrf_id, (name) ? name : "(NULL)");
	}
      else
	{
          if (name)
            {
              namelen = strlen (name);
              if (namelen > VRF_NAMSIZ)
                {
                  zlog_err("Attempt to get/create VRF %u name %s - name too long",
                           vrf_id, name);
                  return NULL;
                }
            }

	  vrf = XCALLOC (MTYPE_VRF, sizeof (struct vrf));
	  if (debug_vrf)
	    zlog_debug ("VRF(%u) %s is created.",
			vrf_id, (name) ? name : "(NULL)");
          if (name)
            {
              strncpy (vrf->name, name, namelen);
              vrf->name[namelen] = '\0';
              listnode_add_sort (vrf_list, vrf);
            }
	}
      vrf->vrf_id = vrf_id;
      rn->info = vrf;
      vrf->node = rn;

      /* Initialize interfaces. */
      if_init (&vrf->iflist);
    }

  if (vrf_master.vrf_new_hook && name) {
    (*vrf_master.vrf_new_hook) (vrf_id, name, &vrf->info);

    if (vrf->info)
      zlog_info ("zvrf is created.");
  }
  return vrf;
}

/* Delete a VRF. This is called in vrf_terminate(). */
void
vrf_delete (struct vrf *vrf)
{
  if (debug_vrf)
    zlog_debug ("VRF %u is to be deleted.", vrf->vrf_id);

  if (vrf_is_enabled (vrf))
    vrf_disable (vrf);

  if (vrf_master.vrf_delete_hook)
    (*vrf_master.vrf_delete_hook) (vrf->vrf_id, vrf->name, &vrf->info);

  if (CHECK_FLAG (vrf->status, VRF_ACTIVE))
    if_terminate (&vrf->iflist);

  if (vrf->node)
    {
      vrf->node->info = NULL;
      route_unlock_node(vrf->node);
    }

  listnode_delete (vrf_list, vrf);

  XFREE (MTYPE_VRF, vrf);
}

/* Look up a VRF by identifier. */
struct vrf *
vrf_lookup (vrf_id_t vrf_id)
{
  struct prefix p;
  struct route_node *rn;
  struct vrf *vrf = NULL;

  vrf_build_key (vrf_id, &p);
  rn = route_node_lookup (vrf_table, &p);
  if (rn)
    {
      vrf = (struct vrf *)rn->info;
      route_unlock_node (rn); /* lookup */
    }
  return vrf;
}

/*
 * Check whether the VRF is enabled - that is, whether the VRF
 * is ready to allocate resources. Currently there's only one
 * type of resource: socket.
 */
static int
vrf_is_enabled (struct vrf *vrf)
{
  return vrf && CHECK_FLAG (vrf->status, VRF_ACTIVE);

  /*Pending: figure out the real use of this routine.. it used to be..
  return vrf && vrf->vrf_id == VRF_DEFAULT;
  */
}

/*
 * Enable a VRF - that is, let the VRF be ready to use.
 * The VRF_ENABLE_HOOK callback will be called to inform
 * that they can allocate resources in this VRF.
 *
 * RETURN: 1 - enabled successfully; otherwise, 0.
 */
int
vrf_enable (struct vrf *vrf)
{
//Pending: see if VRF lib had a reason to leave it for default only
// /* Till now, only the default VRF can be enabled. */
//  if (vrf->vrf_id == VRF_DEFAULT)
//    {
  if (debug_vrf)
    zlog_debug ("VRF %u is enabled.", vrf->vrf_id);

      if (vrf_master.vrf_enable_hook)
        (*vrf_master.vrf_enable_hook) (vrf->vrf_id, vrf->name, &vrf->info);

      return 1;
//    }

//  return 0;
}

/*
 * Disable a VRF - that is, let the VRF be unusable.
 * The VRF_DELETE_HOOK callback will be called to inform
 * that they must release the resources in the VRF.
 */
static void
vrf_disable (struct vrf *vrf)
{
  if (vrf_is_enabled (vrf))
    {
      if (debug_vrf)
	zlog_debug ("VRF %u is to be disabled.", vrf->vrf_id);

      /* Till now, nothing to be done for the default VRF. */
      //Pending: see why this statement.

      if (vrf_master.vrf_disable_hook)
        (*vrf_master.vrf_disable_hook) (vrf->vrf_id, vrf->name, &vrf->info);
    }
}


/* Add a VRF hook. Please add hooks before calling vrf_init(). */
void
vrf_add_hook (int type, int (*func)(vrf_id_t, const char *, void **))
{
  if (debug_vrf)
    zlog_debug ("%s: Add Hook %d to function %p",  __PRETTY_FUNCTION__,
		type, func);

  switch (type) {
  case VRF_NEW_HOOK:
    vrf_master.vrf_new_hook = func;
    break;
  case VRF_DELETE_HOOK:
    vrf_master.vrf_delete_hook = func;
    break;
  case VRF_ENABLE_HOOK:
    vrf_master.vrf_enable_hook = func;
    break;
  case VRF_DISABLE_HOOK:
    vrf_master.vrf_disable_hook = func;
    break;
  default:
    break;
  }
}

/* Return the iterator of the first VRF. */
vrf_iter_t
vrf_first (void)
{
  struct route_node *rn;

  for (rn = route_top (vrf_table); rn; rn = route_next (rn))
    if (rn->info)
      {
        route_unlock_node (rn); /* top/next */
        return (vrf_iter_t)rn;
      }
  return VRF_ITER_INVALID;
}

/* Return the next VRF iterator to the given iterator. */
vrf_iter_t
vrf_next (vrf_iter_t iter)
{
  struct route_node *rn = NULL;

  /* Lock it first because route_next() will unlock it. */
  if (iter != VRF_ITER_INVALID)
    rn = route_next (route_lock_node ((struct route_node *)iter));

  for (; rn; rn = route_next (rn))
    if (rn->info)
      {
        route_unlock_node (rn); /* next */
        return (vrf_iter_t)rn;
      }
  return VRF_ITER_INVALID;
}

/* Return the VRF iterator of the given VRF ID. If it does not exist,
 * the iterator of the next existing VRF is returned. */
vrf_iter_t
vrf_iterator (vrf_id_t vrf_id)
{
  struct prefix p;
  struct route_node *rn;

  vrf_build_key (vrf_id, &p);
  rn = route_node_get (vrf_table, &p);
  if (rn->info)
    {
      /* OK, the VRF exists. */
      route_unlock_node (rn); /* get */
      return (vrf_iter_t)rn;
    }

  /* Find the next VRF. */
  for (rn = route_next (rn); rn; rn = route_next (rn))
    if (rn->info)
      {
        route_unlock_node (rn); /* next */
        return (vrf_iter_t)rn;
      }

  return VRF_ITER_INVALID;
}

/* Obtain the VRF ID from the given VRF iterator. */
vrf_id_t
vrf_iter2id (vrf_iter_t iter)
{
  struct route_node *rn = (struct route_node *) iter;
  return (rn && rn->info) ? ((struct vrf *)rn->info)->vrf_id : VRF_DEFAULT;
}

struct vrf *
vrf_iter2vrf (vrf_iter_t iter)
{
  struct route_node *rn = (struct route_node *) iter;
  return (rn && rn->info) ? (struct vrf *)rn->info : NULL;
}

/* Obtain the data pointer from the given VRF iterator. */
void *
vrf_iter2info (vrf_iter_t iter)
{
  struct route_node *rn = (struct route_node *) iter;
  return (rn && rn->info) ? ((struct vrf *)rn->info)->info : NULL;
}

/* Obtain the interface list from the given VRF iterator. */
struct list *
vrf_iter2iflist (vrf_iter_t iter)
{
  struct route_node *rn = (struct route_node *) iter;
  return (rn && rn->info) ? ((struct vrf *)rn->info)->iflist : NULL;
}

/* Look up a VRF by name. */
struct vrf *
vrf_lookup_by_name (const char *name)
{
  struct vrf *vrf = NULL;
  vrf_iter_t iter;

  for (iter = vrf_first (); iter != VRF_ITER_INVALID; iter = vrf_next (iter))
    {
      vrf = vrf_iter2vrf (iter);
      if (vrf && !strcmp(vrf->name, name))
        return vrf;
    }

  return NULL;
}

vrf_id_t
vrf_name_to_id (const char *name)
{
  struct vrf *vrf;
  vrf_id_t vrf_id = VRF_DEFAULT; //Pending: need a way to return invalid id/ routine not used.

  vrf = vrf_lookup_by_name (name);
  if (vrf)
    vrf_id = vrf->vrf_id;

  return vrf_id;
}

/* Get the data pointer of the specified VRF. If not found, create one. */
void *
vrf_info_get (vrf_id_t vrf_id)
{
  struct vrf *vrf = vrf_get (vrf_id, NULL);
  return vrf->info;
}

/* Look up the data pointer of the specified VRF. */
void *
vrf_info_lookup (vrf_id_t vrf_id)
{
  struct vrf *vrf = vrf_lookup (vrf_id);
  return vrf ? vrf->info : NULL;
}

/* Look up the interface list in a VRF. */
struct list *
vrf_iflist (vrf_id_t vrf_id)
{
   struct vrf * vrf = vrf_lookup (vrf_id);
   return vrf ? vrf->iflist : NULL;
}

/* Get the interface list of the specified VRF. Create one if not find. */
struct list *
vrf_iflist_get (vrf_id_t vrf_id)
{
   struct vrf * vrf = vrf_get (vrf_id, NULL);
   return vrf->iflist;
}

/* Create the interface list for the specified VRF, if needed. */
void
vrf_iflist_create (vrf_id_t vrf_id)
{
   struct vrf * vrf = vrf_lookup (vrf_id);
   if (vrf && !vrf->iflist)
     if_init (&vrf->iflist);
}

/* Free the interface list of the specified VRF. */
void
vrf_iflist_terminate (vrf_id_t vrf_id)
{
   struct vrf * vrf = vrf_lookup (vrf_id);
   if (vrf && vrf->iflist)
     if_terminate (&vrf->iflist);
}

/*
 * VRF bit-map
 */

#define VRF_BITMAP_NUM_OF_GROUPS            8
#define VRF_BITMAP_NUM_OF_BITS_IN_GROUP \
    (UINT16_MAX / VRF_BITMAP_NUM_OF_GROUPS)
#define VRF_BITMAP_NUM_OF_BYTES_IN_GROUP \
    (VRF_BITMAP_NUM_OF_BITS_IN_GROUP / CHAR_BIT + 1) /* +1 for ensure */

#define VRF_BITMAP_GROUP(_id) \
    ((_id) / VRF_BITMAP_NUM_OF_BITS_IN_GROUP)
#define VRF_BITMAP_BIT_OFFSET(_id) \
    ((_id) % VRF_BITMAP_NUM_OF_BITS_IN_GROUP)

#define VRF_BITMAP_INDEX_IN_GROUP(_bit_offset) \
    ((_bit_offset) / CHAR_BIT)
#define VRF_BITMAP_FLAG(_bit_offset) \
    (((u_char)1) << ((_bit_offset) % CHAR_BIT))

struct vrf_bitmap
{
  u_char *groups[VRF_BITMAP_NUM_OF_GROUPS];
};

vrf_bitmap_t
vrf_bitmap_init (void)
{
  return (vrf_bitmap_t) XCALLOC (MTYPE_VRF_BITMAP, sizeof (struct vrf_bitmap));
}

void
vrf_bitmap_free (vrf_bitmap_t bmap)
{
  struct vrf_bitmap *bm = (struct vrf_bitmap *) bmap;
  int i;

  if (bmap == VRF_BITMAP_NULL)
    return;

  for (i = 0; i < VRF_BITMAP_NUM_OF_GROUPS; i++)
    if (bm->groups[i])
      XFREE (MTYPE_VRF_BITMAP, bm->groups[i]);

  XFREE (MTYPE_VRF_BITMAP, bm);
}

void
vrf_bitmap_set (vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
  struct vrf_bitmap *bm = (struct vrf_bitmap *) bmap;
  u_char group = VRF_BITMAP_GROUP (vrf_id);
  u_char offset = VRF_BITMAP_BIT_OFFSET (vrf_id);

  if (bmap == VRF_BITMAP_NULL)
    return;

  if (bm->groups[group] == NULL)
    bm->groups[group] = XCALLOC (MTYPE_VRF_BITMAP,
                                 VRF_BITMAP_NUM_OF_BYTES_IN_GROUP);

  SET_FLAG (bm->groups[group][VRF_BITMAP_INDEX_IN_GROUP (offset)],
            VRF_BITMAP_FLAG (offset));
}

void
vrf_bitmap_unset (vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
  struct vrf_bitmap *bm = (struct vrf_bitmap *) bmap;
  u_char group = VRF_BITMAP_GROUP (vrf_id);
  u_char offset = VRF_BITMAP_BIT_OFFSET (vrf_id);

  if (bmap == VRF_BITMAP_NULL || bm->groups[group] == NULL)
    return;

  UNSET_FLAG (bm->groups[group][VRF_BITMAP_INDEX_IN_GROUP (offset)],
              VRF_BITMAP_FLAG (offset));
}

int
vrf_bitmap_check (vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
  struct vrf_bitmap *bm = (struct vrf_bitmap *) bmap;
  u_char group = VRF_BITMAP_GROUP (vrf_id);
  u_char offset = VRF_BITMAP_BIT_OFFSET (vrf_id);

  if (bmap == VRF_BITMAP_NULL || bm->groups[group] == NULL)
    return 0;

  return CHECK_FLAG (bm->groups[group][VRF_BITMAP_INDEX_IN_GROUP (offset)],
                     VRF_BITMAP_FLAG (offset)) ? 1 : 0;
}

/* Compare interface names, returning an integer greater than, equal to, or
 * less than 0, (following the strcmp convention), according to the
 * relationship between vrfp1 and vrfp2.  Interface names consist of an
 * alphabetic prefix and a numeric suffix.  The primary sort key is
 * lexicographic by name, and then numeric by number.  No number sorts
 * before all numbers.  Examples: de0 < de1, de100 < fxp0 < xl0, devpty <
 * devpty0, de0 < del0
 */
static int
vrf_cmp_func (struct vrf *vrfp1, struct vrf *vrfp2)
{
  return if_cmp_name_func (vrfp1->name, vrfp2->name);
}

/* Initialize VRF module. */
void
vrf_init (void)
{
  struct vrf *default_vrf;

  if (debug_vrf)
    zlog_debug ("%s: Initializing VRF subsystem", __PRETTY_FUNCTION__);

  vrf_list = list_new ();
  vrf_list->cmp = (int (*)(void *, void *))vrf_cmp_func;

  /* Allocate VRF table.  */
  vrf_table = route_table_init ();

  /* The default VRF always exists. */
  default_vrf = vrf_get (VRF_DEFAULT, VRF_DEFAULT_NAME);
  if (!default_vrf)
    {
      zlog_err ("vrf_init: failed to create the default VRF!");
      exit (1);
    }

  /* Enable the default VRF. */
  if (!vrf_enable (default_vrf))
    {
      zlog_err ("vrf_init: failed to enable the default VRF!");
      exit (1);
    }
}

/* Terminate VRF module. */
void
vrf_terminate (void)
{
  struct route_node *rn;
  struct vrf *vrf;

  if (debug_vrf)
    zlog_debug ("%s: Shutting down vrf subsystem", __PRETTY_FUNCTION__);

  for (rn = route_top (vrf_table); rn; rn = route_next (rn))
    if ((vrf = rn->info) != NULL)
      vrf_delete (vrf);

  route_table_finish (vrf_table);
  vrf_table = NULL;
}

/* Create a socket for the VRF. */
int
vrf_socket (int domain, int type, int protocol, vrf_id_t vrf_id)
{
  int ret = -1;

  ret = socket (domain, type, protocol);

  return ret;
}

/*
 * Debug CLI for vrf's
 */
DEFUN (vrf_debug,
      vrf_debug_cmd,
      "debug vrf",
      DEBUG_STR
      "VRF Debugging\n")
{
  debug_vrf = 1;

  return CMD_SUCCESS;
}

DEFUN (no_vrf_debug,
      no_vrf_debug_cmd,
      "no debug vrf",
      NO_STR
      DEBUG_STR
      "VRF Debugging\n")
{
  debug_vrf = 0;

  return CMD_SUCCESS;
}

static int
vrf_write_host (struct vty *vty)
{
  if (debug_vrf)
    vty_out (vty, "debug vrf%s", VTY_NEWLINE);

  return 1;
}

static struct cmd_node vrf_debug_node =
{
  VRF_DEBUG_NODE,
  "",
  1
};

void
vrf_install_commands (void)
{
  install_node (&vrf_debug_node, vrf_write_host);

  install_element (CONFIG_NODE, &vrf_debug_cmd);
  install_element (ENABLE_NODE, &vrf_debug_cmd);
  install_element (CONFIG_NODE, &no_vrf_debug_cmd);
  install_element (ENABLE_NODE, &no_vrf_debug_cmd);
}