[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / mac80211 / mesh_pathtbl.c

/*
 * Copyright (c) 2008 open80211s Ltd.
 * Author:     Luis Carlos Cobo <luisca@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 <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "mesh.h"

/* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
#define INIT_PATHS_SIZE_ORDER	2

/* Keep the mean chain length below this constant */
#define MEAN_CHAIN_LEN		2

#define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
				time_after(jiffies, mpath->exp_time) && \
				!(mpath->flags & MESH_PATH_FIXED))

struct mpath_node {
	struct hlist_node list;
	struct rcu_head rcu;
	/* This indirection allows two different tables to point to the same
	 * mesh_path structure, useful when resizing
	 */
	struct mesh_path *mpath;
};

static struct mesh_table *mesh_paths;

/* This lock will have the grow table function as writer and add / delete nodes
 * as readers. When reading the table (i.e. doing lookups) we are well protected
 * by RCU
 */
static DEFINE_RWLOCK(pathtbl_resize_lock);

/**
 *
 * mesh_path_assign_nexthop - update mesh path next hop
 *
 * @mpath: mesh path to update
 * @sta: next hop to assign
 *
 * Locking: mpath->state_lock must be held when calling this function
 */
void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
{
	rcu_assign_pointer(mpath->next_hop, sta);
}


/**
 * mesh_path_lookup - look up a path in the mesh path table
 * @dst: hardware address (ETH_ALEN length) of destination
 * @dev: local interface
 *
 * Returns: pointer to the mesh path structure, or NULL if not found
 *
 * Locking: must be called within a read rcu section.
 */
struct mesh_path *mesh_path_lookup(u8 *dst, struct net_device *dev)
{
	struct mesh_path *mpath;
	struct hlist_node *n;
	struct hlist_head *bucket;
	struct mesh_table *tbl;
	struct mpath_node *node;

	tbl = rcu_dereference(mesh_paths);

	bucket = &tbl->hash_buckets[mesh_table_hash(dst, dev, tbl)];
	hlist_for_each_entry_rcu(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->dev == dev &&
				memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
			if (MPATH_EXPIRED(mpath)) {
				spin_lock_bh(&mpath->state_lock);
				if (MPATH_EXPIRED(mpath))
					mpath->flags &= ~MESH_PATH_ACTIVE;
				spin_unlock_bh(&mpath->state_lock);
			}
			return mpath;
		}
	}
	return NULL;
}

/**
 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 * @idx: index
 * @dev: local interface
 *
 * Returns: pointer to the mesh path structure, or NULL if not found.
 *
 * Locking: must be called within a read rcu section.
 */
struct mesh_path *mesh_path_lookup_by_idx(int idx, struct net_device *dev)
{
	struct mpath_node *node;
	struct hlist_node *p;
	int i;
	int j = 0;

	for_each_mesh_entry(mesh_paths, p, node, i)
		if (j++ == idx) {
			if (MPATH_EXPIRED(node->mpath)) {
				spin_lock_bh(&node->mpath->state_lock);
				if (MPATH_EXPIRED(node->mpath))
					node->mpath->flags &= ~MESH_PATH_ACTIVE;
				spin_unlock_bh(&node->mpath->state_lock);
			}
			return node->mpath;
		}

	return NULL;
}

/**
 * mesh_path_add - allocate and add a new path to the mesh path table
 * @addr: destination address of the path (ETH_ALEN length)
 * @dev: local interface
 *
 * Returns: 0 on sucess
 *
 * State: the initial state of the new path is set to 0
 */
int mesh_path_add(u8 *dst, struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct mesh_path *mpath, *new_mpath;
	struct mpath_node *node, *new_node;
	struct hlist_head *bucket;
	struct hlist_node *n;
	int grow = 0;
	int err = 0;
	u32 hash_idx;

	if (memcmp(dst, dev->dev_addr, ETH_ALEN) == 0)
		/* never add ourselves as neighbours */
		return -ENOTSUPP;

	if (is_multicast_ether_addr(dst))
		return -ENOTSUPP;

	if (atomic_add_unless(&sdata->u.sta.mpaths, 1, MESH_MAX_MPATHS) == 0)
		return -ENOSPC;

	read_lock(&pathtbl_resize_lock);

	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
	if (!new_mpath) {
		atomic_dec(&sdata->u.sta.mpaths);
		err = -ENOMEM;
		goto endadd2;
	}
	memcpy(new_mpath->dst, dst, ETH_ALEN);
	new_mpath->dev = dev;
	new_mpath->flags = 0;
	skb_queue_head_init(&new_mpath->frame_queue);
	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
	new_node->mpath = new_mpath;
	new_mpath->timer.data = (unsigned long) new_mpath;
	new_mpath->timer.function = mesh_path_timer;
	new_mpath->exp_time = jiffies;
	spin_lock_init(&new_mpath->state_lock);
	init_timer(&new_mpath->timer);

	hash_idx = mesh_table_hash(dst, dev, mesh_paths);
	bucket = &mesh_paths->hash_buckets[hash_idx];

	spin_lock(&mesh_paths->hashwlock[hash_idx]);

	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN)
				== 0) {
			err = -EEXIST;
			atomic_dec(&sdata->u.sta.mpaths);
			kfree(new_node);
			kfree(new_mpath);
			goto endadd;
		}
	}

	hlist_add_head_rcu(&new_node->list, bucket);
	if (atomic_inc_return(&mesh_paths->entries) >=
		mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
		grow = 1;

endadd:
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
endadd2:
	read_unlock(&pathtbl_resize_lock);
	if (!err && grow) {
		struct mesh_table *oldtbl, *newtbl;

		write_lock(&pathtbl_resize_lock);
		oldtbl = mesh_paths;
		newtbl = mesh_table_grow(mesh_paths);
		if (!newtbl) {
			write_unlock(&pathtbl_resize_lock);
			return -ENOMEM;
		}
		rcu_assign_pointer(mesh_paths, newtbl);
		synchronize_rcu();
		mesh_table_free(oldtbl, false);
		write_unlock(&pathtbl_resize_lock);
	}
	return err;
}


/**
 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 *
 * @sta: broken peer link
 *
 * This function must be called from the rate control algorithm if enough
 * delivery errors suggest that a peer link is no longer usable.
 */
void mesh_plink_broken(struct sta_info *sta)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	struct net_device *dev = sta->sdata->dev;
	int i;

	rcu_read_lock();
	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
		spin_lock_bh(&mpath->state_lock);
		if (mpath->next_hop == sta &&
		    mpath->flags & MESH_PATH_ACTIVE &&
		    !(mpath->flags & MESH_PATH_FIXED)) {
			mpath->flags &= ~MESH_PATH_ACTIVE;
			++mpath->dsn;
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_error_tx(mpath->dst,
					cpu_to_le32(mpath->dsn),
					dev->broadcast, dev);
		} else
		spin_unlock_bh(&mpath->state_lock);
	}
	rcu_read_unlock();
}
EXPORT_SYMBOL(mesh_plink_broken);

/**
 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 *
 * @sta - mesh peer to match
 *
 * RCU notes: this function is called when a mesh plink transitions from ESTAB
 * to any other state, since ESTAB state is the only one that allows path
 * creation. This will happen before the sta can be freed (because
 * sta_info_destroy() calls this) so any reader in a rcu read block will be
 * protected against the plink disappearing.
 */
void mesh_path_flush_by_nexthop(struct sta_info *sta)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
		if (mpath->next_hop == sta)
			mesh_path_del(mpath->dst, mpath->dev);
	}
}

void mesh_path_flush(struct net_device *dev)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	for_each_mesh_entry(mesh_paths, p, node, i) {
		mpath = node->mpath;
		if (mpath->dev == dev)
			mesh_path_del(mpath->dst, mpath->dev);
	}
}

static void mesh_path_node_reclaim(struct rcu_head *rp)
{
	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
	struct ieee80211_sub_if_data *sdata =
		IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);

	del_timer_sync(&node->mpath->timer);
	atomic_dec(&sdata->u.sta.mpaths);
	kfree(node->mpath);
	kfree(node);
}

/**
 * mesh_path_del - delete a mesh path from the table
 *
 * @addr: dst address (ETH_ALEN length)
 * @dev: local interface
 *
 * Returns: 0 if succesful
 */
int mesh_path_del(u8 *addr, struct net_device *dev)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_head *bucket;
	struct hlist_node *n;
	int hash_idx;
	int err = 0;

	read_lock(&pathtbl_resize_lock);
	hash_idx = mesh_table_hash(addr, dev, mesh_paths);
	bucket = &mesh_paths->hash_buckets[hash_idx];

	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->dev == dev &&
				memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
			spin_lock_bh(&mpath->state_lock);
			mpath->flags |= MESH_PATH_RESOLVING;
			hlist_del_rcu(&node->list);
			call_rcu(&node->rcu, mesh_path_node_reclaim);
			atomic_dec(&mesh_paths->entries);
			spin_unlock_bh(&mpath->state_lock);
			goto enddel;
		}
	}

	err = -ENXIO;
enddel:
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	return err;
}

/**
 * mesh_path_tx_pending - sends pending frames in a mesh path queue
 *
 * @mpath: mesh path to activate
 *
 * Locking: the state_lock of the mpath structure must NOT be held when calling
 * this function.
 */
void mesh_path_tx_pending(struct mesh_path *mpath)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
			(mpath->flags & MESH_PATH_ACTIVE))
		dev_queue_xmit(skb);
}

/**
 * mesh_path_discard_frame - discard a frame whose path could not be resolved
 *
 * @skb: frame to discard
 * @dev: network device the frame was to be sent through
 *
 * If the frame was beign forwarded from another MP, a PERR frame will be sent
 * to the precursor.
 *
 * Locking: the function must me called within a rcu_read_lock region
 */
void mesh_path_discard_frame(struct sk_buff *skb, struct net_device *dev)
{
	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	struct mesh_path *mpath;
	u32 dsn = 0;

	if (skb->pkt_type == PACKET_OTHERHOST) {
		struct ieee80211s_hdr *prev_meshhdr;
		int mshhdrlen;
		u8 *ra, *da;

		prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb);
		mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr);
		da = skb->data;
		ra = MESH_PREQ(skb);
		mpath = mesh_path_lookup(da, dev);
		if (mpath)
			dsn = ++mpath->dsn;
		mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev);
	}

	kfree_skb(skb);
	sdata->u.sta.mshstats.dropped_frames_no_route++;
}

/**
 * mesh_path_flush_pending - free the pending queue of a mesh path
 *
 * @mpath: mesh path whose queue has to be freed
 *
 * Locking: the function must me called withing a rcu_read_lock region
 */
void mesh_path_flush_pending(struct mesh_path *mpath)
{
	struct ieee80211_sub_if_data *sdata;
	struct sk_buff *skb;

	sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);

	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
			(mpath->flags & MESH_PATH_ACTIVE))
		mesh_path_discard_frame(skb, mpath->dev);
}

/**
 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 *
 * @mpath: the mesh path to modify
 * @next_hop: the next hop to force
 *
 * Locking: this function must be called holding mpath->state_lock
 */
void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
{
	spin_lock_bh(&mpath->state_lock);
	mesh_path_assign_nexthop(mpath, next_hop);
	mpath->dsn = 0xffff;
	mpath->metric = 0;
	mpath->hop_count = 0;
	mpath->exp_time = 0;
	mpath->flags |= MESH_PATH_FIXED;
	mesh_path_activate(mpath);
	spin_unlock_bh(&mpath->state_lock);
	mesh_path_tx_pending(mpath);
}

static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
{
	struct mesh_path *mpath;
	struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
	mpath = node->mpath;
	hlist_del_rcu(p);
	synchronize_rcu();
	if (free_leafs)
		kfree(mpath);
	kfree(node);
}

static void mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
{
	struct mesh_path *mpath;
	struct mpath_node *node, *new_node;
	u32 hash_idx;

	node = hlist_entry(p, struct mpath_node, list);
	mpath = node->mpath;
	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
	new_node->mpath = mpath;
	hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl);
	hlist_add_head(&new_node->list,
			&newtbl->hash_buckets[hash_idx]);
}

int mesh_pathtbl_init(void)
{
	mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
	mesh_paths->free_node = &mesh_path_node_free;
	mesh_paths->copy_node = &mesh_path_node_copy;
	mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
	if (!mesh_paths)
		return -ENOMEM;
	return 0;
}

void mesh_path_expire(struct net_device *dev)
{
	struct mesh_path *mpath;
	struct mpath_node *node;
	struct hlist_node *p;
	int i;

	read_lock(&pathtbl_resize_lock);
	for_each_mesh_entry(mesh_paths, p, node, i) {
		if (node->mpath->dev != dev)
			continue;
		mpath = node->mpath;
		spin_lock_bh(&mpath->state_lock);
		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
		    (!(mpath->flags & MESH_PATH_FIXED)) &&
			time_after(jiffies,
			 mpath->exp_time + MESH_PATH_EXPIRE)) {
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_del(mpath->dst, mpath->dev);
		} else
			spin_unlock_bh(&mpath->state_lock);
	}
	read_unlock(&pathtbl_resize_lock);
}

void mesh_pathtbl_unregister(void)
{
	mesh_table_free(mesh_paths, true);
}
Commit	Line	Data
eb2b9311 LCC	1	/*
	2	* Copyright (c) 2008 open80211s Ltd.
	3	* Author: Luis Carlos Cobo <luisca@cozybit.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/etherdevice.h>
	11	#include <linux/list.h>
	12	#include <linux/netdevice.h>
	13	#include <linux/random.h>
	14	#include <linux/spinlock.h>
	15	#include <linux/string.h>
	16	#include <net/mac80211.h>
	17	#include "ieee80211_i.h"
	18	#include "mesh.h"
	19
	20	/* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
	21	#define INIT_PATHS_SIZE_ORDER 2
	22
	23	/* Keep the mean chain length below this constant */
	24	#define MEAN_CHAIN_LEN 2
	25
	26	#define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
	27	time_after(jiffies, mpath->exp_time) && \
	28	!(mpath->flags & MESH_PATH_FIXED))
	29
	30	struct mpath_node {
	31	struct hlist_node list;
	32	struct rcu_head rcu;
	33	/* This indirection allows two different tables to point to the same
	34	* mesh_path structure, useful when resizing
	35	*/
	36	struct mesh_path *mpath;
	37	};
	38
	39	static struct mesh_table *mesh_paths;
	40
	41	/* This lock will have the grow table function as writer and add / delete nodes
	42	* as readers. When reading the table (i.e. doing lookups) we are well protected
	43	* by RCU
	44	*/
	45	static DEFINE_RWLOCK(pathtbl_resize_lock);
	46
	47	/**
	48	*
	49	* mesh_path_assign_nexthop - update mesh path next hop
	50	*
	51	* @mpath: mesh path to update
	52	* @sta: next hop to assign
	53	*
	54	* Locking: mpath->state_lock must be held when calling this function
	55	*/
	56	void mesh_path_assign_nexthop(struct mesh_path mpath, struct sta_info sta)
	57	{
d0709a65	58	rcu_assign_pointer(mpath->next_hop, sta);
eb2b9311 LCC	59	}
	60
	61
	62	/**
	63	* mesh_path_lookup - look up a path in the mesh path table
	64	* @dst: hardware address (ETH_ALEN length) of destination
	65	* @dev: local interface
	66	*
	67	* Returns: pointer to the mesh path structure, or NULL if not found
	68	*
	69	* Locking: must be called within a read rcu section.
	70	*/
	71	struct mesh_path mesh_path_lookup(u8 dst, struct net_device *dev)
	72	{
	73	struct mesh_path *mpath;
	74	struct hlist_node *n;
	75	struct hlist_head *bucket;
	76	struct mesh_table *tbl;
	77	struct mpath_node *node;
	78
	79	tbl = rcu_dereference(mesh_paths);
	80
	81	bucket = &tbl->hash_buckets[mesh_table_hash(dst, dev, tbl)];
	82	hlist_for_each_entry_rcu(node, n, bucket, list) {
	83	mpath = node->mpath;
	84	if (mpath->dev == dev &&
	85	memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
	86	if (MPATH_EXPIRED(mpath)) {
	87	spin_lock_bh(&mpath->state_lock);
	88	if (MPATH_EXPIRED(mpath))
	89	mpath->flags &= ~MESH_PATH_ACTIVE;
	90	spin_unlock_bh(&mpath->state_lock);
	91	}
	92	return mpath;
	93	}
	94	}
	95	return NULL;
	96	}
	97
	98	/**
	99	* mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
	100	* @idx: index
	101	* @dev: local interface
	102	*
	103	* Returns: pointer to the mesh path structure, or NULL if not found.
	104	*
	105	* Locking: must be called within a read rcu section.
	106	*/
	107	struct mesh_path mesh_path_lookup_by_idx(int idx, struct net_device dev)
	108	{
	109	struct mpath_node *node;
	110	struct hlist_node *p;
	111	int i;
	112	int j = 0;
	113
	114	for_each_mesh_entry(mesh_paths, p, node, i)
	115	if (j++ == idx) {
	116	if (MPATH_EXPIRED(node->mpath)) {
	117	spin_lock_bh(&node->mpath->state_lock);
	118	if (MPATH_EXPIRED(node->mpath))
	119	node->mpath->flags &= ~MESH_PATH_ACTIVE;
	120	spin_unlock_bh(&node->mpath->state_lock);
	121	}
	122	return node->mpath;
123	}
124
125	return NULL;
126	}
127
128	/**
129	* mesh_path_add - allocate and add a new path to the mesh path table
130	* @addr: destination address of the path (ETH_ALEN length)
131	* @dev: local interface
132	*
133	* Returns: 0 on sucess
134	*
135	* State: the initial state of the new path is set to 0
136	*/
137	int mesh_path_add(u8 dst, struct net_device dev)
138	{
139	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
140	struct mesh_path mpath, new_mpath;
141	struct mpath_node node, new_node;
142	struct hlist_head *bucket;
143	struct hlist_node *n;
144	int grow = 0;
145	int err = 0;
146	u32 hash_idx;
147
148	if (memcmp(dst, dev->dev_addr, ETH_ALEN) == 0)
149	/* never add ourselves as neighbours */
150	return -ENOTSUPP;
151
152	if (is_multicast_ether_addr(dst))
153	return -ENOTSUPP;
154
155	if (atomic_add_unless(&sdata->u.sta.mpaths, 1, MESH_MAX_MPATHS) == 0)
156	return -ENOSPC;
157
158	read_lock(&pathtbl_resize_lock);
159
160	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
161	if (!new_mpath) {
162	atomic_dec(&sdata->u.sta.mpaths);
163	err = -ENOMEM;
164	goto endadd2;
165	}
166	memcpy(new_mpath->dst, dst, ETH_ALEN);
167	new_mpath->dev = dev;
168	new_mpath->flags = 0;
169	skb_queue_head_init(&new_mpath->frame_queue);
170	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
171	new_node->mpath = new_mpath;
172	new_mpath->timer.data = (unsigned long) new_mpath;
173	new_mpath->timer.function = mesh_path_timer;
174	new_mpath->exp_time = jiffies;
175	spin_lock_init(&new_mpath->state_lock);
176	init_timer(&new_mpath->timer);
177
178	hash_idx = mesh_table_hash(dst, dev, mesh_paths);
179	bucket = &mesh_paths->hash_buckets[hash_idx];
180
181	spin_lock(&mesh_paths->hashwlock[hash_idx]);
182
183	hlist_for_each_entry(node, n, bucket, list) {
184	mpath = node->mpath;
185	if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN)
186	== 0) {
187	err = -EEXIST;
188	atomic_dec(&sdata->u.sta.mpaths);
189	kfree(new_node);
190	kfree(new_mpath);
191	goto endadd;
192	}
193	}
194
195	hlist_add_head_rcu(&new_node->list, bucket);
196	if (atomic_inc_return(&mesh_paths->entries) >=
197	mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
198	grow = 1;
199
200	endadd:
201	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
202	endadd2:
203	read_unlock(&pathtbl_resize_lock);
204	if (!err && grow) {
205	struct mesh_table oldtbl, newtbl;
206
207	write_lock(&pathtbl_resize_lock);
208	oldtbl = mesh_paths;
209	newtbl = mesh_table_grow(mesh_paths);
210	if (!newtbl) {
211	write_unlock(&pathtbl_resize_lock);
212	return -ENOMEM;
213	}
214	rcu_assign_pointer(mesh_paths, newtbl);
215	synchronize_rcu();
216	mesh_table_free(oldtbl, false);
217	write_unlock(&pathtbl_resize_lock);
218	}
219	return err;
220	}
221
222
223	/**
224	* mesh_plink_broken - deactivates paths and sends perr when a link breaks
225	*
226	* @sta: broken peer link
227	*
228	* This function must be called from the rate control algorithm if enough
229	* delivery errors suggest that a peer link is no longer usable.
230	*/
231	void mesh_plink_broken(struct sta_info *sta)
232	{
233	struct mesh_path *mpath;
234	struct mpath_node *node;
235	struct hlist_node *p;
d0709a65	236	struct net_device *dev = sta->sdata->dev;
eb2b9311 LCC	237	int i;
	238
	239	rcu_read_lock();
	240	for_each_mesh_entry(mesh_paths, p, node, i) {
	241	mpath = node->mpath;
	242	spin_lock_bh(&mpath->state_lock);
	243	if (mpath->next_hop == sta &&
	244	mpath->flags & MESH_PATH_ACTIVE &&
	245	!(mpath->flags & MESH_PATH_FIXED)) {
	246	mpath->flags &= ~MESH_PATH_ACTIVE;
	247	++mpath->dsn;
	248	spin_unlock_bh(&mpath->state_lock);
	249	mesh_path_error_tx(mpath->dst,
	250	cpu_to_le32(mpath->dsn),
	251	dev->broadcast, dev);
	252	} else
	253	spin_unlock_bh(&mpath->state_lock);
	254	}
	255	rcu_read_unlock();
	256	}
c1edd987	257	EXPORT_SYMBOL(mesh_plink_broken);
eb2b9311 LCC	258
	259	/**
	260	* mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
	261	*
	262	* @sta - mesh peer to match
	263	*
	264	* RCU notes: this function is called when a mesh plink transitions from ESTAB
	265	* to any other state, since ESTAB state is the only one that allows path
d0709a65 JB	266	* creation. This will happen before the sta can be freed (because
	267	* sta_info_destroy() calls this) so any reader in a rcu read block will be
	268	* protected against the plink disappearing.
eb2b9311 LCC	269	*/
	270	void mesh_path_flush_by_nexthop(struct sta_info *sta)
	271	{
	272	struct mesh_path *mpath;
	273	struct mpath_node *node;
	274	struct hlist_node *p;
	275	int i;
	276
	277	for_each_mesh_entry(mesh_paths, p, node, i) {
	278	mpath = node->mpath;
	279	if (mpath->next_hop == sta)
cfa22c71	280	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	281	}
	282	}
	283
	284	void mesh_path_flush(struct net_device *dev)
	285	{
	286	struct mesh_path *mpath;
	287	struct mpath_node *node;
	288	struct hlist_node *p;
	289	int i;
	290
	291	for_each_mesh_entry(mesh_paths, p, node, i) {
	292	mpath = node->mpath;
	293	if (mpath->dev == dev)
cfa22c71	294	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	295	}
	296	}
	297
	298	static void mesh_path_node_reclaim(struct rcu_head *rp)
	299	{
	300	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
	301	struct ieee80211_sub_if_data *sdata =
	302	IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);
d0709a65	303
89a1ad69	304	del_timer_sync(&node->mpath->timer);
eb2b9311 LCC	305	atomic_dec(&sdata->u.sta.mpaths);
	306	kfree(node->mpath);
	307	kfree(node);
	308	}
	309
	310	/**
	311	* mesh_path_del - delete a mesh path from the table
	312	*
	313	* @addr: dst address (ETH_ALEN length)
	314	* @dev: local interface
	315	*
	316	* Returns: 0 if succesful
eb2b9311	317	*/
cfa22c71	318	int mesh_path_del(u8 addr, struct net_device dev)
eb2b9311 LCC	319	{
	320	struct mesh_path *mpath;
	321	struct mpath_node *node;
	322	struct hlist_head *bucket;
	323	struct hlist_node *n;
	324	int hash_idx;
	325	int err = 0;
	326
	327	read_lock(&pathtbl_resize_lock);
	328	hash_idx = mesh_table_hash(addr, dev, mesh_paths);
	329	bucket = &mesh_paths->hash_buckets[hash_idx];
	330
	331	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	332	hlist_for_each_entry(node, n, bucket, list) {
	333	mpath = node->mpath;
	334	if (mpath->dev == dev &&
	335	memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
	336	spin_lock_bh(&mpath->state_lock);
cfa22c71 LCC	337	mpath->flags \|= MESH_PATH_RESOLVING;
	338	hlist_del_rcu(&node->list);
	339	call_rcu(&node->rcu, mesh_path_node_reclaim);
	340	atomic_dec(&mesh_paths->entries);
eb2b9311 LCC	341	spin_unlock_bh(&mpath->state_lock);
	342	goto enddel;
	343	}
	344	}
	345
	346	err = -ENXIO;
	347	enddel:
	348	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	349	read_unlock(&pathtbl_resize_lock);
	350	return err;
	351	}
	352
	353	/**
	354	* mesh_path_tx_pending - sends pending frames in a mesh path queue
	355	*
	356	* @mpath: mesh path to activate
	357	*
	358	* Locking: the state_lock of the mpath structure must NOT be held when calling
	359	* this function.
	360	*/
	361	void mesh_path_tx_pending(struct mesh_path *mpath)
	362	{
	363	struct sk_buff *skb;
	364
	365	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
	366	(mpath->flags & MESH_PATH_ACTIVE))
	367	dev_queue_xmit(skb);
	368	}
	369
	370	/**
	371	* mesh_path_discard_frame - discard a frame whose path could not be resolved
	372	*
	373	* @skb: frame to discard
	374	* @dev: network device the frame was to be sent through
	375	*
	376	* If the frame was beign forwarded from another MP, a PERR frame will be sent
	377	* to the precursor.
	378	*
	379	* Locking: the function must me called within a rcu_read_lock region
	380	*/
	381	void mesh_path_discard_frame(struct sk_buff skb, struct net_device dev)
	382	{
	383	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	384	struct mesh_path *mpath;
	385	u32 dsn = 0;
	386
	387	if (skb->pkt_type == PACKET_OTHERHOST) {
	388	struct ieee80211s_hdr *prev_meshhdr;
	389	int mshhdrlen;
	390	u8 ra, da;
	391
	392	prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb);
	393	mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr);
	394	da = skb->data;
	395	ra = MESH_PREQ(skb);
	396	mpath = mesh_path_lookup(da, dev);
	397	if (mpath)
	398	dsn = ++mpath->dsn;
	399	mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev);
	400	}
	401
	402	kfree_skb(skb);
	403	sdata->u.sta.mshstats.dropped_frames_no_route++;
	404	}
405
406	/**
407	* mesh_path_flush_pending - free the pending queue of a mesh path
408	*
409	* @mpath: mesh path whose queue has to be freed
410	*
411	* Locking: the function must me called withing a rcu_read_lock region
412	*/
413	void mesh_path_flush_pending(struct mesh_path *mpath)
414	{
415	struct ieee80211_sub_if_data *sdata;
416	struct sk_buff *skb;
417
418	sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
419
420	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
421	(mpath->flags & MESH_PATH_ACTIVE))
422	mesh_path_discard_frame(skb, mpath->dev);
423	}
424
425	/**
426	* mesh_path_fix_nexthop - force a specific next hop for a mesh path
427	*
428	* @mpath: the mesh path to modify
429	* @next_hop: the next hop to force
430	*
431	* Locking: this function must be called holding mpath->state_lock
432	*/
433	void mesh_path_fix_nexthop(struct mesh_path mpath, struct sta_info next_hop)
434	{
435	spin_lock_bh(&mpath->state_lock);
436	mesh_path_assign_nexthop(mpath, next_hop);
437	mpath->dsn = 0xffff;
438	mpath->metric = 0;
439	mpath->hop_count = 0;
440	mpath->exp_time = 0;
441	mpath->flags \|= MESH_PATH_FIXED;
442	mesh_path_activate(mpath);
443	spin_unlock_bh(&mpath->state_lock);
444	mesh_path_tx_pending(mpath);
445	}
446
447	static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
448	{
449	struct mesh_path *mpath;
450	struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
451	mpath = node->mpath;
452	hlist_del_rcu(p);
453	synchronize_rcu();
454	if (free_leafs)
455	kfree(mpath);
456	kfree(node);
457	}
458
459	static void mesh_path_node_copy(struct hlist_node p, struct mesh_table newtbl)
460	{
461	struct mesh_path *mpath;
462	struct mpath_node node, new_node;
463	u32 hash_idx;
464
465	node = hlist_entry(p, struct mpath_node, list);
466	mpath = node->mpath;
467	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
468	new_node->mpath = mpath;
469	hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl);
470	hlist_add_head(&new_node->list,
471	&newtbl->hash_buckets[hash_idx]);
472	}
473
474	int mesh_pathtbl_init(void)
475	{
476	mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
477	mesh_paths->free_node = &mesh_path_node_free;
478	mesh_paths->copy_node = &mesh_path_node_copy;
479	mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
480	if (!mesh_paths)
481	return -ENOMEM;
482	return 0;
483	}
484
485	void mesh_path_expire(struct net_device *dev)
486	{
487	struct mesh_path *mpath;
488	struct mpath_node *node;
489	struct hlist_node *p;
490	int i;
491
492	read_lock(&pathtbl_resize_lock);
493	for_each_mesh_entry(mesh_paths, p, node, i) {
494	if (node->mpath->dev != dev)
495	continue;
496	mpath = node->mpath;
497	spin_lock_bh(&mpath->state_lock);
498	if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
499	(!(mpath->flags & MESH_PATH_FIXED)) &&
500	time_after(jiffies,
501	mpath->exp_time + MESH_PATH_EXPIRE)) {
502	spin_unlock_bh(&mpath->state_lock);
cfa22c71	503	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	504	} else
	505	spin_unlock_bh(&mpath->state_lock);
	506	}
	507	read_unlock(&pathtbl_resize_lock);
	508	}
	509
	510	void mesh_pathtbl_unregister(void)
	511	{
	512	mesh_table_free(mesh_paths, true);
	513	}