mac80211: support functions for mesh

/*

 * Copyright (c) 2008 open80211s Ltd.

 * Authors:    Luis Carlos Cobo <luisca@cozybit.com>

 * 	       Javier Cardona <javier@cozybit.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include "ieee80211_i.h"

#include "mesh.h"

#define PP_OFFSET 	1		/* Path Selection Protocol */

#define PM_OFFSET	5		/* Path Selection Metric   */

#define CC_OFFSET	9		/* Congestion Control Mode */

#define CAPAB_OFFSET 17

#define ACCEPT_PLINKS 0x80

int mesh_allocated;

static struct kmem_cache *rm_cache;

void ieee80211s_init(void)

{

	mesh_pathtbl_init();

	mesh_allocated = 1;

	rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),

				     0, 0, NULL);

}

void ieee80211s_stop(void)

{

	mesh_pathtbl_unregister();

	kmem_cache_destroy(rm_cache);

}

/**

 * mesh_matches_local - check if the config of a mesh point matches ours

 *

 * @ie: information elements of a management frame from the mesh peer

 * @dev: local mesh interface

 *

 * This function checks if the mesh configuration of a mesh point matches the

 * local mesh configuration, i.e. if both nodes belong to the same mesh network.

 */

bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev)

{

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	struct ieee80211_if_sta *sta = &sdata->u.sta;

	if (sta->mesh_id_len == ie->mesh_id_len &&

		memcmp(sta->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&

		memcmp(sta->mesh_pp_id, ie->mesh_config + PP_OFFSET, 4) == 0 &&

		memcmp(sta->mesh_pm_id, ie->mesh_config + PM_OFFSET, 4) == 0 &&

		memcmp(sta->mesh_cc_id, ie->mesh_config + CC_OFFSET, 4) == 0)

	/*

	 * As support for each feature is added, check for matching

	 * - On mesh config capabilities

	 *   - Power Save Support En

	 *   - Sync support enabled

	 *   - Sync support active

	 *   - Sync support required from peer

	 *   - MDA enabled

	 * - Power management control on fc

	 */

		return true;

	return false;

}

/**

 * mesh_peer_accepts_plinks - check if an mp is willing to establish peer links

 *

 * @ie: information elements of a management frame from the mesh peer

 * @dev: local mesh interface

 */

bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,

			      struct net_device *dev)

{

	return (*(ie->mesh_config + CAPAB_OFFSET) & ACCEPT_PLINKS) != 0;

}

/**

 * mesh_accept_plinks_update: update accepting_plink in local mesh beacons

 *

 * @dev: mesh interface in which mesh beacons are going to be updated

 */

void mesh_accept_plinks_update(struct net_device *dev)

{

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	bool free_plinks;

	/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,

	 * the mesh interface might be able to establish plinks with peers that

	 * are already on the table but are not on ESTAB state. However, in

	 * general the mesh interface is not accepting peer link requests from

	 * new peers, and that must be reflected in the beacon

	 */

	free_plinks = mesh_plink_availables(sdata);

	if (free_plinks != sdata->u.sta.accepting_plinks)

		ieee80211_sta_timer((unsigned long) sdata);

}

void mesh_ids_set_default(struct ieee80211_if_sta *sta)

{

	u8 def_id[4] = {0x00, 0x0F, 0xAC, 0xff};

	memcpy(sta->mesh_pp_id, def_id, 4);

	memcpy(sta->mesh_pm_id, def_id, 4);

	memcpy(sta->mesh_cc_id, def_id, 4);

}

int mesh_rmc_init(struct net_device *dev)

{

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	int i;

	sdata->u.sta.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);

	if (!sdata->u.sta.rmc)

		return -ENOMEM;

	sdata->u.sta.rmc->idx_mask = RMC_BUCKETS - 1;

	for (i = 0; i < RMC_BUCKETS; i++)

		INIT_LIST_HEAD(&sdata->u.sta.rmc->bucket[i].list);

	return 0;

}

void mesh_rmc_free(struct net_device *dev)

{

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	struct mesh_rmc *rmc = sdata->u.sta.rmc;

	struct rmc_entry *p, *n;

	int i;

	if (!sdata->u.sta.rmc)

		return;

	for (i = 0; i < RMC_BUCKETS; i++)

		list_for_each_entry_safe(p, n, &rmc->bucket[i].list, list) {

			list_del(&p->list);

			kmem_cache_free(rm_cache, p);

		}

	kfree(rmc);

	sdata->u.sta.rmc = NULL;

}

/**

 * mesh_rmc_check - Check frame in recent multicast cache and add if absent.

 *

 * @sa:		source address

 * @mesh_hdr:	mesh_header

 *

 * Returns: 0 if the frame is not in the cache, nonzero otherwise.

 *

 * Checks using the source address and the mesh sequence number if we have

 * received this frame lately. If the frame is not in the cache, it is added to

 * it.

 */

int mesh_rmc_check(u8 *sa, struct ieee80211s_hdr *mesh_hdr,

		   struct net_device *dev)

{

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	struct mesh_rmc *rmc = sdata->u.sta.rmc;

	u32 seqnum = 0;

	int entries = 0;

	u8 idx;

	struct rmc_entry *p, *n;

	/* Don't care about endianness since only match matters */

	memcpy(&seqnum, mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));

	idx = mesh_hdr->seqnum[0] & rmc->idx_mask;

	list_for_each_entry_safe(p, n, &rmc->bucket[idx].list, list) {

		++entries;

		if (time_after(jiffies, p->exp_time) ||

				(entries == RMC_QUEUE_MAX_LEN)) {

			list_del(&p->list);

			kmem_cache_free(rm_cache, p);

			--entries;

		} else if ((seqnum == p->seqnum)

				&& (memcmp(sa, p->sa, ETH_ALEN) == 0))

			return -1;

	}

	p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);

	if (!p) {

		printk(KERN_DEBUG "o11s: could not allocate RMC entry\n");

		return 0;

	}

	p->seqnum = seqnum;

	p->exp_time = jiffies + RMC_TIMEOUT;

	memcpy(p->sa, sa, ETH_ALEN);

	list_add(&p->list, &rmc->bucket[idx].list);

	return 0;

}

void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev)

{

	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);

	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);

	struct ieee80211_supported_band *sband;

	u8 *pos;

	int len, i, rate;

	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];

	len = sband->n_bitrates;

	if (len > 8)

		len = 8;

	pos = skb_put(skb, len + 2);

	*pos++ = WLAN_EID_SUPP_RATES;

	*pos++ = len;

	for (i = 0; i < len; i++) {

		rate = sband->bitrates[i].bitrate;

		*pos++ = (u8) (rate / 5);

	}

	if (sband->n_bitrates > len) {

		pos = skb_put(skb, sband->n_bitrates - len + 2);

		*pos++ = WLAN_EID_EXT_SUPP_RATES;

		*pos++ = sband->n_bitrates - len;

		for (i = len; i < sband->n_bitrates; i++) {

			rate = sband->bitrates[i].bitrate;

			*pos++ = (u8) (rate / 5);

		}

	}

	pos = skb_put(skb, 2 + sdata->u.sta.mesh_id_len);

	*pos++ = WLAN_EID_MESH_ID;

	*pos++ = sdata->u.sta.mesh_id_len;

	if (sdata->u.sta.mesh_id_len)

		memcpy(pos, sdata->u.sta.mesh_id, sdata->u.sta.mesh_id_len);

	pos = skb_put(skb, 21);

	*pos++ = WLAN_EID_MESH_CONFIG;

	*pos++ = MESH_CFG_LEN;

	/* Version */

	*pos++ = 1;

	/* Active path selection protocol ID */

	memcpy(pos, sdata->u.sta.mesh_pp_id, 4);

	pos += 4;

	/* Active path selection metric ID   */

	memcpy(pos, sdata->u.sta.mesh_pm_id, 4);

	pos += 4;

	/* Congestion control mode identifier */

	memcpy(pos, sdata->u.sta.mesh_cc_id, 4);

	pos += 4;

	/* Channel precedence:

	 * Not running simple channel unification protocol

	 */

	memset(pos, 0x00, 4);

	pos += 4;

	/* Mesh capability */

	sdata->u.sta.accepting_plinks = mesh_plink_availables(sdata);

	*pos++ = sdata->u.sta.accepting_plinks ? ACCEPT_PLINKS : 0x00;

	*pos++ = 0x00;

	return;

}

u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl)

{

	/* Use last four bytes of hw addr and interface index as hash index */

	return jhash_2words(*(u32 *)(addr+2), dev->ifindex, tbl->hash_rnd)

		& tbl->hash_mask;

}

u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len)

{

	if (!mesh_id_len)

		return 1;

	else if (mesh_id_len == 1)

		return (u8) mesh_id[0];

	else

		return (u8) (mesh_id[0] + 2 * mesh_id[1]);

}

struct mesh_table *mesh_table_alloc(int size_order)

{

	int i;

	struct mesh_table *newtbl;

	newtbl = kmalloc(sizeof(struct mesh_table), GFP_KERNEL);

	if (!newtbl)

		return NULL;

	newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *

			(1 << size_order), GFP_KERNEL);

	if (!newtbl->hash_buckets) {

		kfree(newtbl);

		return NULL;

	}

	newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *

			(1 << size_order), GFP_KERNEL);

	if (!newtbl->hashwlock) {

		kfree(newtbl->hash_buckets);

		kfree(newtbl);

		return NULL;

	}

	newtbl->size_order = size_order;

	newtbl->hash_mask = (1 << size_order) - 1;

	atomic_set(&newtbl->entries,  0);

	get_random_bytes(&newtbl->hash_rnd,

			sizeof(newtbl->hash_rnd));

	for (i = 0; i <= newtbl->hash_mask; i++)

		spin_lock_init(&newtbl->hashwlock[i]);

	return newtbl;

}

void mesh_table_free(struct mesh_table *tbl, bool free_leafs)

{

	struct hlist_head *mesh_hash;

	struct hlist_node *p, *q;

	int i;

	mesh_hash = tbl->hash_buckets;

	for (i = 0; i <= tbl->hash_mask; i++) {

		spin_lock(&tbl->hashwlock[i]);

		hlist_for_each_safe(p, q, &mesh_hash[i]) {

			tbl->free_node(p, free_leafs);

			atomic_dec(&tbl->entries);

		}

		spin_unlock(&tbl->hashwlock[i]);

	}

	kfree(tbl->hash_buckets);

	kfree(tbl->hashwlock);

	kfree(tbl);

}

static void ieee80211_mesh_path_timer(unsigned long data)

{

	struct ieee80211_sub_if_data *sdata =

		(struct ieee80211_sub_if_data *) data;

	struct ieee80211_if_sta *ifsta = &sdata->u.sta;

	struct ieee80211_local *local = wdev_priv(&sdata->wdev);

	queue_work(local->hw.workqueue, &ifsta->work);

}

struct mesh_table *mesh_table_grow(struct mesh_table *tbl)

{

	struct mesh_table *newtbl;

	struct hlist_head *oldhash;

	struct hlist_node *p;

	int err = 0;

	int i;

	if (atomic_read(&tbl->entries)

			< tbl->mean_chain_len * (tbl->hash_mask + 1)) {

		err = -EPERM;

		goto endgrow;

	}

	newtbl = mesh_table_alloc(tbl->size_order + 1);

	if (!newtbl) {

		err = -ENOMEM;

		goto endgrow;

	}

	newtbl->free_node = tbl->free_node;

	newtbl->mean_chain_len = tbl->mean_chain_len;

	newtbl->copy_node = tbl->copy_node;

	atomic_set(&newtbl->entries, atomic_read(&tbl->entries));

	oldhash = tbl->hash_buckets;

	for (i = 0; i <= tbl->hash_mask; i++)

		hlist_for_each(p, &oldhash[i])

			tbl->copy_node(p, newtbl);

endgrow:

	if (err)

		return NULL;

	else

		return newtbl;

}