/*
 * Copyright (C) 2009 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

/* increase the reference counter for this originator */

#include "main.h"
#include "originator.h"
#include "hash.h"
#include "translation-table.h"
#include "routing.h"

static DECLARE_DELAYED_WORK(purge_orig_wq, purge_orig);

static void start_purge_timer(void)
{
	queue_delayed_work(bat_event_workqueue, &purge_orig_wq, 1 * HZ);
}

int originator_init(void)
{
	unsigned long flags;
	if (orig_hash)
		return 1;

	spin_lock_irqsave(&orig_hash_lock, flags);
	orig_hash = hash_new(128, compare_orig, choose_orig);

	if (!orig_hash)
		goto err;

	spin_unlock_irqrestore(&orig_hash_lock, flags);
	start_purge_timer();
	return 1;

err:
	spin_unlock_irqrestore(&orig_hash_lock, flags);
	return 0;
}

void originator_free(void)
{
	unsigned long flags;

	if (!orig_hash)
		return;

	cancel_delayed_work_sync(&purge_orig_wq);

	spin_lock_irqsave(&orig_hash_lock, flags);
	hash_delete(orig_hash, free_orig_node);
	orig_hash = NULL;
	spin_unlock_irqrestore(&orig_hash_lock, flags);
}

struct neigh_node *
create_neighbor(struct orig_node *orig_node, struct orig_node *orig_neigh_node,
		uint8_t *neigh, struct batman_if *if_incoming)
{
	struct neigh_node *neigh_node;

	bat_dbg(DBG_BATMAN, "Creating new last-hop neighbor of originator\n");

	neigh_node = kzalloc(sizeof(struct neigh_node), GFP_ATOMIC);
	if (!neigh_node)
		return NULL;

	INIT_LIST_HEAD(&neigh_node->list);

	memcpy(neigh_node->addr, neigh, ETH_ALEN);
	neigh_node->orig_node = orig_neigh_node;
	neigh_node->if_incoming = if_incoming;

	list_add_tail(&neigh_node->list, &orig_node->neigh_list);
	return neigh_node;
}

void free_orig_node(void *data)
{
	struct list_head *list_pos, *list_pos_tmp;
	struct neigh_node *neigh_node;
	struct orig_node *orig_node = (struct orig_node *)data;

	/* for all neighbors towards this originator ... */
	list_for_each_safe(list_pos, list_pos_tmp, &orig_node->neigh_list) {
		neigh_node = list_entry(list_pos, struct neigh_node, list);

		list_del(list_pos);
		kfree(neigh_node);
	}

	hna_global_del_orig(orig_node, "originator timed out");

	kfree(orig_node->bcast_own);
	kfree(orig_node->bcast_own_sum);
	kfree(orig_node);
}

/* this function finds or creates an originator entry for the given
 * address if it does not exits */
struct orig_node *get_orig_node(uint8_t *addr)
{
	struct orig_node *orig_node;
	struct hashtable_t *swaphash;
	int size;

	orig_node = ((struct orig_node *)hash_find(orig_hash, addr));

	if (orig_node != NULL)
		return orig_node;

	bat_dbg(DBG_BATMAN, "Creating new originator: %pM \n", addr);

	orig_node = kzalloc(sizeof(struct orig_node), GFP_ATOMIC);
	if (!orig_node)
		return NULL;

	INIT_LIST_HEAD(&orig_node->neigh_list);

	memcpy(orig_node->orig, addr, ETH_ALEN);
	orig_node->router = NULL;
	orig_node->batman_if = NULL;
	orig_node->hna_buff = NULL;

	size = num_ifs * sizeof(TYPE_OF_WORD) * NUM_WORDS;

	orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
	if (!orig_node->bcast_own)
		goto free_orig_node;

	size = num_ifs * sizeof(uint8_t);
	orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
	if (!orig_node->bcast_own_sum)
		goto free_bcast_own;

	if (hash_add(orig_hash, orig_node) < 0)
		goto free_bcast_own_sum;

	if (orig_hash->elements * 4 > orig_hash->size) {
		swaphash = hash_resize(orig_hash, orig_hash->size * 2);

		if (swaphash == NULL)
			printk(KERN_ERR
			       "batman-adv:Couldn't resize orig hash table \n");
		else
			orig_hash = swaphash;
	}

	return orig_node;
free_bcast_own_sum:
	kfree(orig_node->bcast_own_sum);
free_bcast_own:
	kfree(orig_node->bcast_own);
free_orig_node:
	kfree(orig_node);
	return NULL;
}

static bool purge_orig_neighbors(struct orig_node *orig_node,
				 struct neigh_node **best_neigh_node)
{
	struct list_head *list_pos, *list_pos_tmp;
	struct neigh_node *neigh_node;
	bool neigh_purged = false;

	*best_neigh_node = NULL;


	/* for all neighbors towards this originator ... */
	list_for_each_safe(list_pos, list_pos_tmp, &orig_node->neigh_list) {
		neigh_node = list_entry(list_pos, struct neigh_node, list);

		if (time_after(jiffies,
			       (neigh_node->last_valid +
				((PURGE_TIMEOUT * HZ) / 1000)))) {

			bat_dbg(DBG_BATMAN, "neighbor timeout: originator %pM, neighbor: %pM, last_valid %lu\n", orig_node->orig, neigh_node->addr, (neigh_node->last_valid / HZ));

			neigh_purged = true;
			list_del(list_pos);
			kfree(neigh_node);
		} else {
			if ((*best_neigh_node == NULL) ||
			    (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
				*best_neigh_node = neigh_node;
		}
	}
	return neigh_purged;
}


static bool purge_orig_node(struct orig_node *orig_node)
{
	struct neigh_node *best_neigh_node;

	if (time_after(jiffies,
		       (orig_node->last_valid +
			((2 * PURGE_TIMEOUT * HZ) / 1000)))) {

		bat_dbg(DBG_BATMAN,
			"Originator timeout: originator %pM, last_valid %lu\n",
			orig_node->orig, (orig_node->last_valid / HZ));
		return true;
	} else {
		if (purge_orig_neighbors(orig_node, &best_neigh_node))
			update_routes(orig_node, best_neigh_node,
				      orig_node->hna_buff,
				      orig_node->hna_buff_len);
	}
	return false;
}

void purge_orig(struct work_struct *work)
{
	HASHIT(hashit);
	struct orig_node *orig_node;
	unsigned long flags;

	spin_lock_irqsave(&orig_hash_lock, flags);

	/* for all origins... */
	while (hash_iterate(orig_hash, &hashit)) {
		orig_node = hashit.bucket->data;
		if (purge_orig_node(orig_node)) {
			hash_remove_bucket(orig_hash, &hashit);
			free_orig_node(orig_node);
		}
	}

	spin_unlock_irqrestore(&orig_hash_lock, flags);

	start_purge_timer();
}