[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, or NULL for all entries
 *
 * 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 (dev && node->mpath->dev != dev)
			continue;
		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;

	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
	if (!new_mpath) {
		atomic_dec(&sdata->u.sta.mpaths);
		err = -ENOMEM;
		goto endadd2;
	}
	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
	if (!new_node) {
		kfree(new_mpath);
		atomic_dec(&sdata->u.sta.mpaths);
		err = -ENOMEM;
		goto endadd2;
	}

	read_lock(&pathtbl_resize_lock);
	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->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]);
	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);
		write_unlock(&pathtbl_resize_lock);

		synchronize_rcu();
		mesh_table_free(oldtbl, false);
	}
endadd2:
	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
 * PLINK_ESTAB to any other state, since PLINK_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
2a8ca29a	101	* @dev: local interface, or NULL for all entries
eb2b9311 LCC	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
2a8ca29a LCC	114	for_each_mesh_entry(mesh_paths, p, node, i) {
	115	if (dev && node->mpath->dev != dev)
	116	continue;
eb2b9311 LCC	117	if (j++ == idx) {
	118	if (MPATH_EXPIRED(node->mpath)) {
	119	spin_lock_bh(&node->mpath->state_lock);
	120	if (MPATH_EXPIRED(node->mpath))
	121	node->mpath->flags &= ~MESH_PATH_ACTIVE;
	122	spin_unlock_bh(&node->mpath->state_lock);
	123	}
	124	return node->mpath;
	125	}
2a8ca29a	126	}
eb2b9311 LCC	127
	128	return NULL;
	129	}
	130
	131	/**
	132	* mesh_path_add - allocate and add a new path to the mesh path table
	133	* @addr: destination address of the path (ETH_ALEN length)
	134	* @dev: local interface
	135	*
	136	* Returns: 0 on sucess
	137	*
	138	* State: the initial state of the new path is set to 0
	139	*/
	140	int mesh_path_add(u8 dst, struct net_device dev)
	141	{
	142	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	143	struct mesh_path mpath, new_mpath;
	144	struct mpath_node node, new_node;
	145	struct hlist_head *bucket;
	146	struct hlist_node *n;
	147	int grow = 0;
	148	int err = 0;
	149	u32 hash_idx;
	150
	151	if (memcmp(dst, dev->dev_addr, ETH_ALEN) == 0)
	152	/* never add ourselves as neighbours */
	153	return -ENOTSUPP;
	154
	155	if (is_multicast_ether_addr(dst))
	156	return -ENOTSUPP;
	157
	158	if (atomic_add_unless(&sdata->u.sta.mpaths, 1, MESH_MAX_MPATHS) == 0)
	159	return -ENOSPC;
	160
eb2b9311 LCC	161	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
	162	if (!new_mpath) {
	163	atomic_dec(&sdata->u.sta.mpaths);
	164	err = -ENOMEM;
	165	goto endadd2;
	166	}
0eb03d5a PE	167	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
	168	if (!new_node) {
	169	kfree(new_mpath);
	170	atomic_dec(&sdata->u.sta.mpaths);
	171	err = -ENOMEM;
	172	goto endadd2;
	173	}
f84e71a9 PE	174
f84e71a9 PE	175	read_lock(&pathtbl_resize_lock);
eb2b9311 LCC	176	memcpy(new_mpath->dst, dst, ETH_ALEN);
	177	new_mpath->dev = dev;
	178	new_mpath->flags = 0;
	179	skb_queue_head_init(&new_mpath->frame_queue);
eb2b9311 LCC	180	new_node->mpath = new_mpath;
	181	new_mpath->timer.data = (unsigned long) new_mpath;
	182	new_mpath->timer.function = mesh_path_timer;
	183	new_mpath->exp_time = jiffies;
	184	spin_lock_init(&new_mpath->state_lock);
	185	init_timer(&new_mpath->timer);
	186
	187	hash_idx = mesh_table_hash(dst, dev, mesh_paths);
	188	bucket = &mesh_paths->hash_buckets[hash_idx];
	189
	190	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	191
	192	hlist_for_each_entry(node, n, bucket, list) {
	193	mpath = node->mpath;
	194	if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN)
	195	== 0) {
	196	err = -EEXIST;
	197	atomic_dec(&sdata->u.sta.mpaths);
	198	kfree(new_node);
	199	kfree(new_mpath);
	200	goto endadd;
	201	}
	202	}
	203
	204	hlist_add_head_rcu(&new_node->list, bucket);
	205	if (atomic_inc_return(&mesh_paths->entries) >=
	206	mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
	207	grow = 1;
	208
	209	endadd:
	210	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
eb2b9311 LCC	211	read_unlock(&pathtbl_resize_lock);
	212	if (!err && grow) {
	213	struct mesh_table oldtbl, newtbl;
	214
	215	write_lock(&pathtbl_resize_lock);
	216	oldtbl = mesh_paths;
	217	newtbl = mesh_table_grow(mesh_paths);
	218	if (!newtbl) {
	219	write_unlock(&pathtbl_resize_lock);
	220	return -ENOMEM;
	221	}
	222	rcu_assign_pointer(mesh_paths, newtbl);
6d6936e2 PE	223	write_unlock(&pathtbl_resize_lock);
6d6936e2 PE	224
eb2b9311 LCC	225	synchronize_rcu();
eb2b9311 LCC	226	mesh_table_free(oldtbl, false);
eb2b9311	227	}
f84e71a9	228	endadd2:
eb2b9311 LCC	229	return err;
	230	}
	231
	232
	233	/**
	234	* mesh_plink_broken - deactivates paths and sends perr when a link breaks
	235	*
	236	* @sta: broken peer link
	237	*
	238	* This function must be called from the rate control algorithm if enough
	239	* delivery errors suggest that a peer link is no longer usable.
	240	*/
	241	void mesh_plink_broken(struct sta_info *sta)
	242	{
	243	struct mesh_path *mpath;
	244	struct mpath_node *node;
	245	struct hlist_node *p;
d0709a65	246	struct net_device *dev = sta->sdata->dev;
eb2b9311 LCC	247	int i;
	248
	249	rcu_read_lock();
	250	for_each_mesh_entry(mesh_paths, p, node, i) {
	251	mpath = node->mpath;
	252	spin_lock_bh(&mpath->state_lock);
	253	if (mpath->next_hop == sta &&
	254	mpath->flags & MESH_PATH_ACTIVE &&
	255	!(mpath->flags & MESH_PATH_FIXED)) {
	256	mpath->flags &= ~MESH_PATH_ACTIVE;
	257	++mpath->dsn;
	258	spin_unlock_bh(&mpath->state_lock);
	259	mesh_path_error_tx(mpath->dst,
	260	cpu_to_le32(mpath->dsn),
	261	dev->broadcast, dev);
	262	} else
	263	spin_unlock_bh(&mpath->state_lock);
	264	}
	265	rcu_read_unlock();
	266	}
c1edd987	267	EXPORT_SYMBOL(mesh_plink_broken);
eb2b9311 LCC	268
	269	/**
	270	* mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
	271	*
	272	* @sta - mesh peer to match
	273	*
b4e08ea1 LCC	274	* RCU notes: this function is called when a mesh plink transitions from
	275	* PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
	276	* allows path creation. This will happen before the sta can be freed (because
d0709a65 JB	277	* sta_info_destroy() calls this) so any reader in a rcu read block will be
d0709a65 JB	278	* protected against the plink disappearing.
eb2b9311 LCC	279	*/
	280	void mesh_path_flush_by_nexthop(struct sta_info *sta)
	281	{
	282	struct mesh_path *mpath;
	283	struct mpath_node *node;
	284	struct hlist_node *p;
	285	int i;
	286
	287	for_each_mesh_entry(mesh_paths, p, node, i) {
	288	mpath = node->mpath;
	289	if (mpath->next_hop == sta)
cfa22c71	290	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	291	}
	292	}
	293
	294	void mesh_path_flush(struct net_device *dev)
	295	{
	296	struct mesh_path *mpath;
	297	struct mpath_node *node;
	298	struct hlist_node *p;
	299	int i;
	300
	301	for_each_mesh_entry(mesh_paths, p, node, i) {
	302	mpath = node->mpath;
	303	if (mpath->dev == dev)
cfa22c71	304	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	305	}
	306	}
	307
	308	static void mesh_path_node_reclaim(struct rcu_head *rp)
	309	{
	310	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
	311	struct ieee80211_sub_if_data *sdata =
	312	IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);
d0709a65	313
89a1ad69	314	del_timer_sync(&node->mpath->timer);
eb2b9311 LCC	315	atomic_dec(&sdata->u.sta.mpaths);
	316	kfree(node->mpath);
	317	kfree(node);
	318	}
	319
	320	/**
	321	* mesh_path_del - delete a mesh path from the table
	322	*
	323	* @addr: dst address (ETH_ALEN length)
	324	* @dev: local interface
	325	*
	326	* Returns: 0 if succesful
eb2b9311	327	*/
cfa22c71	328	int mesh_path_del(u8 addr, struct net_device dev)
eb2b9311 LCC	329	{
	330	struct mesh_path *mpath;
	331	struct mpath_node *node;
	332	struct hlist_head *bucket;
	333	struct hlist_node *n;
	334	int hash_idx;
	335	int err = 0;
	336
	337	read_lock(&pathtbl_resize_lock);
	338	hash_idx = mesh_table_hash(addr, dev, mesh_paths);
	339	bucket = &mesh_paths->hash_buckets[hash_idx];
	340
	341	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	342	hlist_for_each_entry(node, n, bucket, list) {
	343	mpath = node->mpath;
	344	if (mpath->dev == dev &&
	345	memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
	346	spin_lock_bh(&mpath->state_lock);
cfa22c71 LCC	347	mpath->flags \|= MESH_PATH_RESOLVING;
	348	hlist_del_rcu(&node->list);
	349	call_rcu(&node->rcu, mesh_path_node_reclaim);
	350	atomic_dec(&mesh_paths->entries);
eb2b9311 LCC	351	spin_unlock_bh(&mpath->state_lock);
	352	goto enddel;
	353	}
	354	}
	355
	356	err = -ENXIO;
	357	enddel:
	358	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	359	read_unlock(&pathtbl_resize_lock);
	360	return err;
	361	}
	362
	363	/**
	364	* mesh_path_tx_pending - sends pending frames in a mesh path queue
	365	*
	366	* @mpath: mesh path to activate
	367	*
	368	* Locking: the state_lock of the mpath structure must NOT be held when calling
	369	* this function.
	370	*/
	371	void mesh_path_tx_pending(struct mesh_path *mpath)
	372	{
	373	struct sk_buff *skb;
	374
	375	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
	376	(mpath->flags & MESH_PATH_ACTIVE))
	377	dev_queue_xmit(skb);
	378	}
	379
	380	/**
	381	* mesh_path_discard_frame - discard a frame whose path could not be resolved
	382	*
	383	* @skb: frame to discard
	384	* @dev: network device the frame was to be sent through
	385	*
	386	* If the frame was beign forwarded from another MP, a PERR frame will be sent
	387	* to the precursor.
	388	*
	389	* Locking: the function must me called within a rcu_read_lock region
	390	*/
	391	void mesh_path_discard_frame(struct sk_buff skb, struct net_device dev)
	392	{
	393	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	394	struct mesh_path *mpath;
	395	u32 dsn = 0;
	396
	397	if (skb->pkt_type == PACKET_OTHERHOST) {
	398	struct ieee80211s_hdr *prev_meshhdr;
	399	int mshhdrlen;
	400	u8 ra, da;
	401
	402	prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb);
	403	mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr);
	404	da = skb->data;
	405	ra = MESH_PREQ(skb);
	406	mpath = mesh_path_lookup(da, dev);
	407	if (mpath)
	408	dsn = ++mpath->dsn;
	409	mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev);
	410	}
	411
	412	kfree_skb(skb);
	413	sdata->u.sta.mshstats.dropped_frames_no_route++;
	414	}
415
416	/**
417	* mesh_path_flush_pending - free the pending queue of a mesh path
418	*
419	* @mpath: mesh path whose queue has to be freed
420	*
421	* Locking: the function must me called withing a rcu_read_lock region
422	*/
423	void mesh_path_flush_pending(struct mesh_path *mpath)
424	{
425	struct ieee80211_sub_if_data *sdata;
426	struct sk_buff *skb;
427
428	sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
429
430	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
431	(mpath->flags & MESH_PATH_ACTIVE))
432	mesh_path_discard_frame(skb, mpath->dev);
433	}
434
435	/**
436	* mesh_path_fix_nexthop - force a specific next hop for a mesh path
437	*
438	* @mpath: the mesh path to modify
439	* @next_hop: the next hop to force
440	*
441	* Locking: this function must be called holding mpath->state_lock
442	*/
443	void mesh_path_fix_nexthop(struct mesh_path mpath, struct sta_info next_hop)
444	{
445	spin_lock_bh(&mpath->state_lock);
446	mesh_path_assign_nexthop(mpath, next_hop);
447	mpath->dsn = 0xffff;
448	mpath->metric = 0;
449	mpath->hop_count = 0;
450	mpath->exp_time = 0;
451	mpath->flags \|= MESH_PATH_FIXED;
452	mesh_path_activate(mpath);
453	spin_unlock_bh(&mpath->state_lock);
454	mesh_path_tx_pending(mpath);
455	}
456
457	static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
458	{
459	struct mesh_path *mpath;
460	struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
461	mpath = node->mpath;
462	hlist_del_rcu(p);
463	synchronize_rcu();
464	if (free_leafs)
465	kfree(mpath);
466	kfree(node);
467	}
468
469	static void mesh_path_node_copy(struct hlist_node p, struct mesh_table newtbl)
470	{
471	struct mesh_path *mpath;
472	struct mpath_node node, new_node;
473	u32 hash_idx;
474
475	node = hlist_entry(p, struct mpath_node, list);
476	mpath = node->mpath;
477	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
478	new_node->mpath = mpath;
479	hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl);
480	hlist_add_head(&new_node->list,
481	&newtbl->hash_buckets[hash_idx]);
482	}
483
484	int mesh_pathtbl_init(void)
485	{
486	mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
487	mesh_paths->free_node = &mesh_path_node_free;
488	mesh_paths->copy_node = &mesh_path_node_copy;
489	mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
490	if (!mesh_paths)
491	return -ENOMEM;
492	return 0;
493	}
494
495	void mesh_path_expire(struct net_device *dev)
496	{
497	struct mesh_path *mpath;
498	struct mpath_node *node;
499	struct hlist_node *p;
500	int i;
501
502	read_lock(&pathtbl_resize_lock);
503	for_each_mesh_entry(mesh_paths, p, node, i) {
504	if (node->mpath->dev != dev)
505	continue;
506	mpath = node->mpath;
507	spin_lock_bh(&mpath->state_lock);
508	if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
509	(!(mpath->flags & MESH_PATH_FIXED)) &&
510	time_after(jiffies,
511	mpath->exp_time + MESH_PATH_EXPIRE)) {
512	spin_unlock_bh(&mpath->state_lock);
cfa22c71	513	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	514	} else
	515	spin_unlock_bh(&mpath->state_lock);
	516	}
	517	read_unlock(&pathtbl_resize_lock);
	518	}
	519
	520	void mesh_pathtbl_unregister(void)
	521	{
	522	mesh_table_free(mesh_paths, true);
	523	}