/*
 * EIGRP Interface Functions.
 * Copyright (C) 2013-2016
 * Authors:
 *   Donnie Savage
 *   Jan Janovic
 *   Matej Perina
 *   Peter Orsag
 *   Peter Paluch
 *   Frantisek Gazo
 *   Tomas Hvorkovy
 *   Martin Kontsek
 *   Lukas Koribsky
 *
 * 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 this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include "thread.h"
#include "linklist.h"
#include "prefix.h"
#include "if.h"
#include "table.h"
#include "memory.h"
#include "command.h"
#include "stream.h"
#include "log.h"
#include "keychain.h"
#include "vrf.h"

#include "eigrpd/eigrp_structs.h"
#include "eigrpd/eigrpd.h"
#include "eigrpd/eigrp_interface.h"
#include "eigrpd/eigrp_neighbor.h"
#include "eigrpd/eigrp_packet.h"
#include "eigrpd/eigrp_zebra.h"
#include "eigrpd/eigrp_vty.h"
#include "eigrpd/eigrp_network.h"
#include "eigrpd/eigrp_topology.h"
#include "eigrpd/eigrp_memory.h"

static void
eigrp_delete_from_if (struct interface *, struct eigrp_interface *);

static void
eigrp_add_to_if (struct interface *ifp, struct eigrp_interface *ei)
{
  struct route_node *rn;
  struct prefix p;

  p = *ei->address;
  p.prefixlen = IPV4_MAX_PREFIXLEN;

  rn = route_node_get (IF_OIFS (ifp), &p);
  /* rn->info should either be NULL or equal to this ei
   * as route_node_get may return an existing node
   */
  assert (!rn->info || rn->info == ei);
  rn->info = ei;
}

struct eigrp_interface *
eigrp_if_new (struct eigrp *eigrp, struct interface *ifp, struct prefix *p)
{
  struct eigrp_interface *ei;
  int i;

  if ((ei = eigrp_if_table_lookup (ifp, p)) == NULL)
    {
      ei = XCALLOC (MTYPE_EIGRP_IF, sizeof (struct eigrp_interface));
      memset (ei, 0, sizeof (struct eigrp_interface));
    }
  else
    return ei;

  /* Set zebra interface pointer. */
  ei->ifp = ifp;
  ei->address = p;

  eigrp_add_to_if (ifp, ei);
  listnode_add (eigrp->eiflist, ei);

  ei->type = EIGRP_IFTYPE_BROADCAST;

  /* Initialize neighbor list. */
  ei->nbrs = list_new ();

  ei->crypt_seqnum = time (NULL);

  /* Initialize lists */
  for (i = 0; i < EIGRP_FILTER_MAX; i++)
    {
      ei->list[i] = NULL;
      ei->prefix[i] = NULL;
      ei->routemap[i] = NULL;
    }

  return ei;
}

/* lookup ei for specified prefix/ifp */
struct eigrp_interface *
eigrp_if_table_lookup (struct interface *ifp, struct prefix *prefix)
{
  struct prefix p;
  struct route_node *rn;
  struct eigrp_interface *rninfo = NULL;

  p = *prefix;
  p.prefixlen = IPV4_MAX_PREFIXLEN;

  /* route_node_get implicitly locks */
  if ((rn = route_node_lookup (IF_OIFS (ifp), &p)))
    {
      rninfo = (struct eigrp_interface *) rn->info;
      route_unlock_node (rn);
    }

  return rninfo;
}

int
eigrp_if_delete_hook (struct interface *ifp)
{
  struct route_node *rn;

  route_table_finish (IF_OIFS (ifp));

  for (rn = route_top (IF_OIFS_PARAMS (ifp)); rn; rn = route_next (rn))
    if (rn->info)
      eigrp_del_if_params (rn->info);
  route_table_finish (IF_OIFS_PARAMS (ifp));

  XFREE (MTYPE_EIGRP_IF_INFO, ifp->info);
  ifp->info = NULL;

  return 0;
}

struct list *eigrp_iflist;

void
eigrp_if_init ()
{
  /* Initialize Zebra interface data structure. */
  if_add_hook (IF_NEW_HOOK, eigrp_if_new_hook);
  if_add_hook (IF_DELETE_HOOK, eigrp_if_delete_hook);
}

int
eigrp_if_new_hook (struct interface *ifp)
{
  int rc = 0;

  ifp->info = XCALLOC (MTYPE_EIGRP_IF_INFO, sizeof (struct eigrp_if_info));

  IF_OIFS (ifp) = route_table_init ();
  IF_OIFS_PARAMS (ifp) = route_table_init ();

  IF_DEF_PARAMS (ifp) = eigrp_new_if_params ();

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), v_hello);
  IF_DEF_PARAMS (ifp)->v_hello = (u_int32_t) EIGRP_HELLO_INTERVAL_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), v_wait);
  IF_DEF_PARAMS (ifp)->v_wait = (u_int16_t) EIGRP_HOLD_INTERVAL_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), bandwidth);
  IF_DEF_PARAMS (ifp)->bandwidth = (u_int32_t) EIGRP_BANDWIDTH_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), delay);
  IF_DEF_PARAMS (ifp)->delay = (u_int32_t) EIGRP_DELAY_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), reliability);
  IF_DEF_PARAMS (ifp)->reliability = (u_char) EIGRP_RELIABILITY_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), load);
  IF_DEF_PARAMS (ifp)->load = (u_char) EIGRP_LOAD_DEFAULT;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), auth_type);
  IF_DEF_PARAMS (ifp)->auth_type = EIGRP_AUTH_TYPE_NONE;

  SET_IF_PARAM (IF_DEF_PARAMS (ifp), auth_keychain);
  IF_DEF_PARAMS (ifp)->auth_keychain= NULL;

  return rc;
}

struct eigrp_if_params *
eigrp_new_if_params (void)
{
  struct eigrp_if_params *eip;

  eip = XCALLOC (MTYPE_EIGRP_IF_PARAMS, sizeof (struct eigrp_if_params));
  if (!eip)
    return NULL;

  UNSET_IF_PARAM (eip, passive_interface);
  UNSET_IF_PARAM (eip, v_hello);
  UNSET_IF_PARAM (eip, v_wait);
  UNSET_IF_PARAM (eip, bandwidth);
  UNSET_IF_PARAM (eip, delay);
  UNSET_IF_PARAM (eip, reliability);
  UNSET_IF_PARAM (eip, load);
  UNSET_IF_PARAM (eip, auth_keychain);
  UNSET_IF_PARAM (eip, auth_type);

  return eip;
}

void
eigrp_del_if_params (struct eigrp_if_params *eip)
{
  if(eip->auth_keychain)
    free(eip->auth_keychain);

  XFREE (MTYPE_EIGRP_IF_PARAMS, eip);
}

struct eigrp_if_params *
eigrp_lookup_if_params (struct interface *ifp, struct in_addr addr)
{
  struct prefix_ipv4 p;
  struct route_node *rn;

  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = addr;

  rn = route_node_lookup (IF_OIFS_PARAMS (ifp), (struct prefix*) &p);

  if (rn)
    {
      route_unlock_node (rn);
      return rn->info;
    }

  return NULL;
}

int
eigrp_if_up (struct eigrp_interface *ei)
{
  struct eigrp_prefix_entry *pe;
  struct eigrp_neighbor_entry *ne;
  struct eigrp_metrics metric;
  struct eigrp_interface *ei2;
  struct listnode *node, *nnode;
  struct eigrp *eigrp = eigrp_lookup ();

  if (ei == NULL)
    return 0;

  if (eigrp != NULL)
    eigrp_adjust_sndbuflen (eigrp, ei->ifp->mtu);
  else
    zlog_warn ("%s: eigrp_lookup () returned NULL", __func__);
  eigrp_if_stream_set (ei);

  /* Set multicast memberships appropriately for new state. */
  eigrp_if_set_multicast (ei);

  thread_add_event(master, eigrp_hello_timer, ei, (1), NULL);

  /*Prepare metrics*/
  metric.bandwith = eigrp_bandwidth_to_scaled (EIGRP_IF_PARAM (ei,bandwidth));
  metric.delay = eigrp_delay_to_scaled (EIGRP_IF_PARAM (ei,delay));
  metric.load = EIGRP_IF_PARAM (ei,load);
  metric.reliability = EIGRP_IF_PARAM (ei,reliability);
  metric.mtu[0] = 0xDC;
  metric.mtu[1] = 0x05;
  metric.mtu[2] = 0x00;
  metric.hop_count = 0;
  metric.flags = 0;
  metric.tag = 0;

  /*Add connected entry to topology table*/

  struct prefix_ipv4 *dest_addr = prefix_ipv4_new ();

  dest_addr->family = AF_INET;
  dest_addr->prefix = ei->connected->address->u.prefix4;
  dest_addr->prefixlen = ei->connected->address->prefixlen;
  apply_mask_ipv4 (dest_addr);
  pe = eigrp_topology_table_lookup_ipv4 (eigrp->topology_table, dest_addr);

  if (pe == NULL)
    {
      pe = eigrp_prefix_entry_new ();
      pe->serno = eigrp->serno;
      pe->destination_ipv4 = prefix_ipv4_new ();
      prefix_copy ((struct prefix *)pe->destination_ipv4,
		   (struct prefix *)&dest_addr);
      pe->af = AF_INET;
      pe->nt = EIGRP_TOPOLOGY_TYPE_CONNECTED;

      pe->state = EIGRP_FSM_STATE_PASSIVE;
      pe->fdistance = eigrp_calculate_metrics (eigrp, &metric);
      pe->req_action |= EIGRP_FSM_NEED_UPDATE;
      eigrp_prefix_entry_add (eigrp->topology_table, pe);
      listnode_add(eigrp->topology_changes_internalIPV4, pe);
    }
  ne = eigrp_neighbor_entry_new ();
  ne->ei = ei;
  ne->reported_metric = metric;
  ne->total_metric = metric;
  ne->distance = eigrp_calculate_metrics (eigrp, &metric);
  ne->reported_distance = 0;
  ne->prefix = pe;
  ne->adv_router = eigrp->neighbor_self;
  ne->flags = EIGRP_NEIGHBOR_ENTRY_SUCCESSOR_FLAG;
  eigrp_neighbor_entry_add (pe, ne);

  for (ALL_LIST_ELEMENTS (eigrp->eiflist, node, nnode, ei2))
    {
      if (ei2->nbrs->count != 0)
        {
          eigrp_update_send (ei2);
        }
    }

  pe->req_action &= ~EIGRP_FSM_NEED_UPDATE;
  listnode_delete(eigrp->topology_changes_internalIPV4, pe);

  return 1;
}

int
eigrp_if_down (struct eigrp_interface *ei)
{
  struct listnode *node, *nnode;
  struct eigrp_neighbor *nbr;

  if (ei == NULL)
    return 0;

  /* Shutdown packet reception and sending */
  if(ei->t_hello)
    THREAD_OFF (ei->t_hello);

  eigrp_if_stream_unset (ei);

  /*Set infinite metrics to routes learned by this interface and start query process*/
  for (ALL_LIST_ELEMENTS (ei->nbrs, node, nnode, nbr))
    {
      eigrp_nbr_delete(nbr);
    }

  return 1;
}

void
eigrp_if_stream_set (struct eigrp_interface *ei)
{
  /* set output fifo queue. */
  if (ei->obuf == NULL)
    ei->obuf = eigrp_fifo_new ();
}

void
eigrp_if_stream_unset (struct eigrp_interface *ei)
{
  struct eigrp *eigrp = ei->eigrp;

  if (ei->obuf)
    {
      eigrp_fifo_free (ei->obuf);
      ei->obuf = NULL;

      if (ei->on_write_q)
        {
          listnode_delete (eigrp->oi_write_q, ei);
          if (list_isempty (eigrp->oi_write_q))
            thread_cancel (eigrp->t_write);
          ei->on_write_q = 0;
        }
    }
}

void
eigrp_if_set_multicast (struct eigrp_interface *ei)
{
  if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_ACTIVE))
    {
      /* The interface should belong to the EIGRP-all-routers group. */
      if (!EI_MEMBER_CHECK (ei, MEMBER_ALLROUTERS)
          && (eigrp_if_add_allspfrouters (ei->eigrp, ei->address,
                                          ei->ifp->ifindex) >= 0))
        /* Set the flag only if the system call to join succeeded. */
        EI_MEMBER_JOINED (ei, MEMBER_ALLROUTERS);
    }
  else
    {
      /* The interface should NOT belong to the EIGRP-all-routers group. */
      if (EI_MEMBER_CHECK (ei, MEMBER_ALLROUTERS))
        {
          /* Only actually drop if this is the last reference */
          if (EI_MEMBER_COUNT (ei, MEMBER_ALLROUTERS) == 1)
            eigrp_if_drop_allspfrouters (ei->eigrp, ei->address,
                                         ei->ifp->ifindex);
          /* Unset the flag regardless of whether the system call to leave
             the group succeeded, since it's much safer to assume that
             we are not a member. */
          EI_MEMBER_LEFT (ei, MEMBER_ALLROUTERS);
        }
    }
}

u_char
eigrp_default_iftype (struct interface *ifp)
{
  if (if_is_pointopoint (ifp))
    return EIGRP_IFTYPE_POINTOPOINT;
  else if (if_is_loopback (ifp))
    return EIGRP_IFTYPE_LOOPBACK;
  else
    return EIGRP_IFTYPE_BROADCAST;
}

void
eigrp_if_free (struct eigrp_interface *ei, int source)
{
  struct prefix_ipv4 dest_addr;
  struct eigrp_prefix_entry *pe;
  struct eigrp *eigrp = eigrp_lookup ();

  if (source == INTERFACE_DOWN_BY_VTY)
    {
      THREAD_OFF (ei->t_hello);
      eigrp_hello_send(ei,EIGRP_HELLO_GRACEFUL_SHUTDOWN, NULL);
    }

  dest_addr.family = AF_INET;
  dest_addr.prefix = ei->connected->address->u.prefix4;
  dest_addr.prefixlen = ei->connected->address->prefixlen;
  apply_mask_ipv4(&dest_addr);
  pe = eigrp_topology_table_lookup_ipv4 (eigrp->topology_table, &dest_addr);
  if (pe)
    eigrp_prefix_entry_delete (eigrp->topology_table, pe);

  eigrp_if_down (ei);

  list_delete (ei->nbrs);
  eigrp_delete_from_if (ei->ifp, ei);
  listnode_delete (ei->eigrp->eiflist, ei);

  thread_cancel_event (master, ei);

  memset (ei, 0, sizeof (*ei));
  XFREE (MTYPE_EIGRP_IF, ei);
}

static void
eigrp_delete_from_if (struct interface *ifp, struct eigrp_interface *ei)
{
  struct route_node *rn;
  struct prefix p;

  p = *ei->address;
  p.prefixlen = IPV4_MAX_PREFIXLEN;

  rn = route_node_lookup (IF_OIFS (ei->ifp), &p);
  assert (rn);
  assert (rn->info);
  rn->info = NULL;
  route_unlock_node (rn);
  route_unlock_node (rn);
}

/* Simulate down/up on the interface.  This is needed, for example, when
   the MTU changes. */
void
eigrp_if_reset (struct interface *ifp)
{
  struct route_node *rn;

  for (rn = route_top (IF_OIFS (ifp)); rn; rn = route_next (rn))
    {
      struct eigrp_interface *ei;

      if ((ei = rn->info) == NULL)
        continue;

      eigrp_if_down (ei);
      eigrp_if_up (ei);
    }
}

struct eigrp_interface *
eigrp_if_lookup_by_local_addr (struct eigrp *eigrp, struct interface *ifp,
                               struct in_addr address)
{
  struct listnode *node;
  struct eigrp_interface *ei;

  for (ALL_LIST_ELEMENTS_RO (eigrp->eiflist, node, ei))
    {
      if (ifp && ei->ifp != ifp)
        continue;

      if (IPV4_ADDR_SAME (&address, &ei->address->u.prefix4))
        return ei;
    }

  return NULL;
}

/**
 * @fn eigrp_if_lookup_by_name
 *
 * @param[in]		eigrp		EIGRP process
 * @param[in]		if_name 	Name of the interface
 *
 * @return struct eigrp_interface *
 *
 * @par
 * Function is used for lookup interface by name.
 */
struct eigrp_interface *
eigrp_if_lookup_by_name (struct eigrp *eigrp, const char *if_name)
{
  struct eigrp_interface *ei;
  struct listnode *node;

  /* iterate over all eigrp interfaces */
  for (ALL_LIST_ELEMENTS_RO (eigrp->eiflist, node, ei))
    {
      /* compare int name with eigrp interface's name */
      if(strcmp(ei->ifp->name, if_name) == 0)
        {
          return ei;
        }
    }

  return NULL;
}

/* determine receiving interface by ifp and source address */
struct eigrp_interface *
eigrp_if_lookup_recv_if (struct eigrp *eigrp, struct in_addr src,
                         struct interface *ifp)
{
  struct route_node *rn;
  struct prefix_ipv4 addr;
  struct eigrp_interface *ei, *match;

  addr.family = AF_INET;
  addr.prefix = src;
  addr.prefixlen = IPV4_MAX_BITLEN;

  match = NULL;

  for (rn = route_top (IF_OIFS (ifp)); rn; rn = route_next (rn))
    {
      ei = rn->info;

      if (!ei) /* oi can be NULL for PtP aliases */
        continue;

      if (if_is_loopback (ei->ifp))
        continue;

      if (prefix_match (CONNECTED_PREFIX (ei->connected),
                        (struct prefix *) &addr))
        {
          if ((match == NULL)
              || (match->address->prefixlen < ei->address->prefixlen))
            match = ei;
        }
    }

  return match;
}

u_int32_t
eigrp_bandwidth_to_scaled (u_int32_t bandwidth)
{
  uint64_t temp_bandwidth = (256ull * 10000000) / bandwidth;

  temp_bandwidth =
    temp_bandwidth < EIGRP_MAX_METRIC ? temp_bandwidth : EIGRP_MAX_METRIC;

  return (u_int32_t) temp_bandwidth;
}

u_int32_t
eigrp_scaled_to_bandwidth (u_int32_t scaled)
{
  uint64_t temp_scaled = scaled * (256ull * 10000000);

  temp_scaled =
    temp_scaled < EIGRP_MAX_METRIC ? temp_scaled : EIGRP_MAX_METRIC;

  return (u_int32_t) temp_scaled;
}

u_int32_t
eigrp_delay_to_scaled (u_int32_t delay)
{
  return delay * 256;
}

u_int32_t
eigrp_scaled_to_delay (u_int32_t scaled)
{
  return scaled / 256;
}