/* Copyright (C) 2013-2016 B.A.T.M.A.N. contributors:
 *
 * Linus Lüssing, Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program 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; if not, see <http://www.gnu.org/licenses/>.
 */

#include "bat_algo.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/bug.h>
#include <linux/cache.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/netdevice.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include "bat_v_elp.h"
#include "bat_v_ogm.h"
#include "hard-interface.h"
#include "hash.h"
#include "originator.h"
#include "packet.h"

static void batadv_v_iface_activate(struct batadv_hard_iface *hard_iface)
{
        /* B.A.T.M.A.N. V does not use any queuing mechanism, therefore it can
         * set the interface as ACTIVE right away, without any risk of race
         * condition
         */
        if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
                hard_iface->if_status = BATADV_IF_ACTIVE;
}

static int batadv_v_iface_enable(struct batadv_hard_iface *hard_iface)
{
        int ret;

        ret = batadv_v_elp_iface_enable(hard_iface);
        if (ret < 0)
                return ret;

        ret = batadv_v_ogm_iface_enable(hard_iface);
        if (ret < 0)
                batadv_v_elp_iface_disable(hard_iface);

        /* enable link throughput auto-detection by setting the throughput
         * override to zero
         */
        atomic_set(&hard_iface->bat_v.throughput_override, 0);

        return ret;
}

static void batadv_v_iface_disable(struct batadv_hard_iface *hard_iface)
{
        batadv_v_elp_iface_disable(hard_iface);
}

static void batadv_v_iface_update_mac(struct batadv_hard_iface *hard_iface)
{
}

static void batadv_v_primary_iface_set(struct batadv_hard_iface *hard_iface)
{
        batadv_v_elp_primary_iface_set(hard_iface);
        batadv_v_ogm_primary_iface_set(hard_iface);
}

static void
batadv_v_hardif_neigh_init(struct batadv_hardif_neigh_node *hardif_neigh)
{
        ewma_throughput_init(&hardif_neigh->bat_v.throughput);
        INIT_WORK(&hardif_neigh->bat_v.metric_work,
                  batadv_v_elp_throughput_metric_update);
}

static void batadv_v_ogm_schedule(struct batadv_hard_iface *hard_iface)
{
}

static void batadv_v_ogm_emit(struct batadv_forw_packet *forw_packet)
{
}

/**
 * batadv_v_orig_print_neigh - print neighbors for the originator table
 * @orig_node: the orig_node for which the neighbors are printed
 * @if_outgoing: outgoing interface for these entries
 * @seq: debugfs table seq_file struct
 *
 * Must be called while holding an rcu lock.
 */
static void
batadv_v_orig_print_neigh(struct batadv_orig_node *orig_node,
                          struct batadv_hard_iface *if_outgoing,
                          struct seq_file *seq)
{
        struct batadv_neigh_node *neigh_node;
        struct batadv_neigh_ifinfo *n_ifinfo;

        hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
                n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
                if (!n_ifinfo)
                        continue;

                seq_printf(seq, " %pM (%9u.%1u)",
                           neigh_node->addr,
                           n_ifinfo->bat_v.throughput / 10,
                           n_ifinfo->bat_v.throughput % 10);

                batadv_neigh_ifinfo_put(n_ifinfo);
        }
}

/**
 * batadv_v_hardif_neigh_print - print a single ELP neighbour node
 * @seq: neighbour table seq_file struct
 * @hardif_neigh: hardif neighbour information
 */
static void
batadv_v_hardif_neigh_print(struct seq_file *seq,
                            struct batadv_hardif_neigh_node *hardif_neigh)
{
        int last_secs, last_msecs;
        u32 throughput;

        last_secs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen) / 1000;
        last_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen) % 1000;
        throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);

        seq_printf(seq, "%pM %4i.%03is (%9u.%1u) [%10s]\n",
                   hardif_neigh->addr, last_secs, last_msecs, throughput / 10,
                   throughput % 10, hardif_neigh->if_incoming->net_dev->name);
}

/**
 * batadv_v_neigh_print - print the single hop neighbour list
 * @bat_priv: the bat priv with all the soft interface information
 * @seq: neighbour table seq_file struct
 */
static void batadv_v_neigh_print(struct batadv_priv *bat_priv,
                                 struct seq_file *seq)
{
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct batadv_hardif_neigh_node *hardif_neigh;
        struct batadv_hard_iface *hard_iface;
        int batman_count = 0;

        seq_printf(seq, "  %-15s %s (%11s) [%10s]\n", "Neighbor",
                   "last-seen", "throughput", "IF");

        rcu_read_lock();
        list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
                if (hard_iface->soft_iface != net_dev)
                        continue;

                hlist_for_each_entry_rcu(hardif_neigh,
                                         &hard_iface->neigh_list, list) {
                        batadv_v_hardif_neigh_print(seq, hardif_neigh);
                        batman_count++;
                }
        }
        rcu_read_unlock();

        if (batman_count == 0)
                seq_puts(seq, "No batman nodes in range ...\n");
}

/**
 * batadv_v_orig_print - print the originator table
 * @bat_priv: the bat priv with all the soft interface information
 * @seq: debugfs table seq_file struct
 * @if_outgoing: the outgoing interface for which this should be printed
 */
static void batadv_v_orig_print(struct batadv_priv *bat_priv,
                                struct seq_file *seq,
                                struct batadv_hard_iface *if_outgoing)
{
        struct batadv_neigh_node *neigh_node;
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        int last_seen_msecs, last_seen_secs;
        struct batadv_orig_node *orig_node;
        struct batadv_neigh_ifinfo *n_ifinfo;
        unsigned long last_seen_jiffies;
        struct hlist_head *head;
        int batman_count = 0;
        u32 i;

        seq_printf(seq, "  %-15s %s (%11s) %17s [%10s]: %20s ...\n",
                   "Originator", "last-seen", "throughput", "Nexthop",
                   "outgoingIF", "Potential nexthops");

        for (i = 0; i < hash->size; i++) {
                head = &hash->table[i];

                rcu_read_lock();
                hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
                        neigh_node = batadv_orig_router_get(orig_node,
                                                            if_outgoing);
                        if (!neigh_node)
                                continue;

                        n_ifinfo = batadv_neigh_ifinfo_get(neigh_node,
                                                           if_outgoing);
                        if (!n_ifinfo)
                                goto next;

                        last_seen_jiffies = jiffies - orig_node->last_seen;
                        last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
                        last_seen_secs = last_seen_msecs / 1000;
                        last_seen_msecs = last_seen_msecs % 1000;

                        seq_printf(seq, "%pM %4i.%03is (%9u.%1u) %pM [%10s]:",
                                   orig_node->orig, last_seen_secs,
                                   last_seen_msecs,
                                   n_ifinfo->bat_v.throughput / 10,
                                   n_ifinfo->bat_v.throughput % 10,
                                   neigh_node->addr,
                                   neigh_node->if_incoming->net_dev->name);

                        batadv_v_orig_print_neigh(orig_node, if_outgoing, seq);
                        seq_puts(seq, "\n");
                        batman_count++;

next:
                        batadv_neigh_node_put(neigh_node);
                        if (n_ifinfo)
                                batadv_neigh_ifinfo_put(n_ifinfo);
                }
                rcu_read_unlock();
        }

        if (batman_count == 0)
                seq_puts(seq, "No batman nodes in range ...\n");
}

static int batadv_v_neigh_cmp(struct batadv_neigh_node *neigh1,
                              struct batadv_hard_iface *if_outgoing1,
                              struct batadv_neigh_node *neigh2,
                              struct batadv_hard_iface *if_outgoing2)
{
        struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;

        ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
        ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);

        if (WARN_ON(!ifinfo1 || !ifinfo2))
                return 0;

        return ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
}

static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
                                  struct batadv_hard_iface *if_outgoing1,
                                  struct batadv_neigh_node *neigh2,
                                  struct batadv_hard_iface *if_outgoing2)
{
        struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
        u32 threshold;

        ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
        ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);

        threshold = ifinfo1->bat_v.throughput / 4;
        threshold = ifinfo1->bat_v.throughput - threshold;

        return ifinfo2->bat_v.throughput > threshold;
}

static struct batadv_algo_ops batadv_batman_v __read_mostly = {
        .name = "BATMAN_V",
        .bat_iface_activate = batadv_v_iface_activate,
        .bat_iface_enable = batadv_v_iface_enable,
        .bat_iface_disable = batadv_v_iface_disable,
        .bat_iface_update_mac = batadv_v_iface_update_mac,
        .bat_primary_iface_set = batadv_v_primary_iface_set,
        .bat_hardif_neigh_init = batadv_v_hardif_neigh_init,
        .bat_ogm_emit = batadv_v_ogm_emit,
        .bat_ogm_schedule = batadv_v_ogm_schedule,
        .bat_orig_print = batadv_v_orig_print,
        .bat_neigh_cmp = batadv_v_neigh_cmp,
        .bat_neigh_is_similar_or_better = batadv_v_neigh_is_sob,
        .bat_neigh_print = batadv_v_neigh_print,
};

/**
 * batadv_v_mesh_init - initialize the B.A.T.M.A.N. V private resources for a
 *  mesh
 * @bat_priv: the object representing the mesh interface to initialise
 *
 * Return: 0 on success or a negative error code otherwise
 */
int batadv_v_mesh_init(struct batadv_priv *bat_priv)
{
        return batadv_v_ogm_init(bat_priv);
}

/**
 * batadv_v_mesh_free - free the B.A.T.M.A.N. V private resources for a mesh
 * @bat_priv: the object representing the mesh interface to free
 */
void batadv_v_mesh_free(struct batadv_priv *bat_priv)
{
        batadv_v_ogm_free(bat_priv);
}

/**
 * batadv_v_init - B.A.T.M.A.N. V initialization function
 *
 * Description: Takes care of initializing all the subcomponents.
 * It is invoked upon module load only.
 *
 * Return: 0 on success or a negative error code otherwise
 */
int __init batadv_v_init(void)
{
        int ret;

        /* B.A.T.M.A.N. V echo location protocol packet  */
        ret = batadv_recv_handler_register(BATADV_ELP,
                                           batadv_v_elp_packet_recv);
        if (ret < 0)
                return ret;

        ret = batadv_recv_handler_register(BATADV_OGM2,
                                           batadv_v_ogm_packet_recv);
        if (ret < 0)
                goto elp_unregister;

        ret = batadv_algo_register(&batadv_batman_v);
        if (ret < 0)
                goto ogm_unregister;

        return ret;

ogm_unregister:
        batadv_recv_handler_unregister(BATADV_OGM2);

elp_unregister:
        batadv_recv_handler_unregister(BATADV_ELP);

        return ret;
}