[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)
{
	__sta_info_get(sta);
	if (mpath->next_hop)
		sta_info_put(mpath->next_hop);
	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->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 (since we hold
 * a reference to it) so any reader in a rcu read block will be protected
 * against the plink dissapearing.
 */
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);
	if (node->mpath->next_hop)
		sta_info_put(node->mpath->next_hop);
	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
 *
 * State: if the path is being resolved, the deletion will be postponed until
 * the path resolution completes or times out.
 */
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);
			if (mpath->flags & MESH_PATH_RESOLVING) {
				mpath->flags |= MESH_PATH_DELETE;
			} else {
				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	{
	58	__sta_info_get(sta);
	59	if (mpath->next_hop)
	60	sta_info_put(mpath->next_hop);
	61	mpath->next_hop = sta;
	62	}
	63
	64
65	/**
66	* mesh_path_lookup - look up a path in the mesh path table
67	* @dst: hardware address (ETH_ALEN length) of destination
68	* @dev: local interface
69	*
70	* Returns: pointer to the mesh path structure, or NULL if not found
71	*
72	* Locking: must be called within a read rcu section.
73	*/
74	struct mesh_path mesh_path_lookup(u8 dst, struct net_device *dev)
75	{
76	struct mesh_path *mpath;
77	struct hlist_node *n;
78	struct hlist_head *bucket;
79	struct mesh_table *tbl;
80	struct mpath_node *node;
81
82	tbl = rcu_dereference(mesh_paths);
83
84	bucket = &tbl->hash_buckets[mesh_table_hash(dst, dev, tbl)];
85	hlist_for_each_entry_rcu(node, n, bucket, list) {
86	mpath = node->mpath;
87	if (mpath->dev == dev &&
88	memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
89	if (MPATH_EXPIRED(mpath)) {
90	spin_lock_bh(&mpath->state_lock);
91	if (MPATH_EXPIRED(mpath))
92	mpath->flags &= ~MESH_PATH_ACTIVE;
93	spin_unlock_bh(&mpath->state_lock);
94	}
95	return mpath;
96	}
97	}
98	return NULL;
99	}
100
101	/**
102	* mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
103	* @idx: index
104	* @dev: local interface
105	*
106	* Returns: pointer to the mesh path structure, or NULL if not found.
107	*
108	* Locking: must be called within a read rcu section.
109	*/
110	struct mesh_path mesh_path_lookup_by_idx(int idx, struct net_device dev)
111	{
112	struct mpath_node *node;
113	struct hlist_node *p;
114	int i;
115	int j = 0;
116
117	for_each_mesh_entry(mesh_paths, p, node, i)
118	if (j++ == idx) {
119	if (MPATH_EXPIRED(node->mpath)) {
120	spin_lock_bh(&node->mpath->state_lock);
121	if (MPATH_EXPIRED(node->mpath))
122	node->mpath->flags &= ~MESH_PATH_ACTIVE;
123	spin_unlock_bh(&node->mpath->state_lock);
124	}
125	return node->mpath;
126	}
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
161	read_lock(&pathtbl_resize_lock);
162
163	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
164	if (!new_mpath) {
165	atomic_dec(&sdata->u.sta.mpaths);
166	err = -ENOMEM;
167	goto endadd2;
168	}
169	memcpy(new_mpath->dst, dst, ETH_ALEN);
170	new_mpath->dev = dev;
171	new_mpath->flags = 0;
172	skb_queue_head_init(&new_mpath->frame_queue);
173	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
174	new_node->mpath = new_mpath;
175	new_mpath->timer.data = (unsigned long) new_mpath;
176	new_mpath->timer.function = mesh_path_timer;
177	new_mpath->exp_time = jiffies;
178	spin_lock_init(&new_mpath->state_lock);
179	init_timer(&new_mpath->timer);
180
181	hash_idx = mesh_table_hash(dst, dev, mesh_paths);
182	bucket = &mesh_paths->hash_buckets[hash_idx];
183
184	spin_lock(&mesh_paths->hashwlock[hash_idx]);
185
186	hlist_for_each_entry(node, n, bucket, list) {
187	mpath = node->mpath;
188	if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN)
189	== 0) {
190	err = -EEXIST;
191	atomic_dec(&sdata->u.sta.mpaths);
192	kfree(new_node);
193	kfree(new_mpath);
194	goto endadd;
195	}
196	}
197
198	hlist_add_head_rcu(&new_node->list, bucket);
199	if (atomic_inc_return(&mesh_paths->entries) >=
200	mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
201	grow = 1;
202
203	endadd:
204	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
205	endadd2:
206	read_unlock(&pathtbl_resize_lock);
207	if (!err && grow) {
208	struct mesh_table oldtbl, newtbl;
209
210	write_lock(&pathtbl_resize_lock);
211	oldtbl = mesh_paths;
212	newtbl = mesh_table_grow(mesh_paths);
213	if (!newtbl) {
214	write_unlock(&pathtbl_resize_lock);
215	return -ENOMEM;
216	}
217	rcu_assign_pointer(mesh_paths, newtbl);
218	synchronize_rcu();
219	mesh_table_free(oldtbl, false);
220	write_unlock(&pathtbl_resize_lock);
221	}
222	return err;
223	}
224
225
226	/**
227	* mesh_plink_broken - deactivates paths and sends perr when a link breaks
228	*
229	* @sta: broken peer link
230	*
231	* This function must be called from the rate control algorithm if enough
232	* delivery errors suggest that a peer link is no longer usable.
233	*/
234	void mesh_plink_broken(struct sta_info *sta)
235	{
236	struct mesh_path *mpath;
237	struct mpath_node *node;
238	struct hlist_node *p;
239	struct net_device *dev = sta->dev;
240	int i;
241
242	rcu_read_lock();
243	for_each_mesh_entry(mesh_paths, p, node, i) {
244	mpath = node->mpath;
245	spin_lock_bh(&mpath->state_lock);
246	if (mpath->next_hop == sta &&
247	mpath->flags & MESH_PATH_ACTIVE &&
248	!(mpath->flags & MESH_PATH_FIXED)) {
249	mpath->flags &= ~MESH_PATH_ACTIVE;
250	++mpath->dsn;
251	spin_unlock_bh(&mpath->state_lock);
252	mesh_path_error_tx(mpath->dst,
253	cpu_to_le32(mpath->dsn),
254	dev->broadcast, dev);
255	} else
256	spin_unlock_bh(&mpath->state_lock);
257	}
258	rcu_read_unlock();
259	}
c1edd987	260	EXPORT_SYMBOL(mesh_plink_broken);
eb2b9311 LCC	261
	262	/**
	263	* mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
	264	*
	265	* @sta - mesh peer to match
	266	*
	267	* RCU notes: this function is called when a mesh plink transitions from ESTAB
	268	* to any other state, since ESTAB state is the only one that allows path
	269	* creation. This will happen before the sta can be freed (since we hold
	270	* a reference to it) so any reader in a rcu read block will be protected
	271	* against the plink dissapearing.
	272	*/
	273	void mesh_path_flush_by_nexthop(struct sta_info *sta)
	274	{
	275	struct mesh_path *mpath;
	276	struct mpath_node *node;
	277	struct hlist_node *p;
	278	int i;
	279
	280	for_each_mesh_entry(mesh_paths, p, node, i) {
	281	mpath = node->mpath;
	282	if (mpath->next_hop == sta)
	283	mesh_path_del(mpath->dst, mpath->dev);
	284	}
	285	}
	286
	287	void mesh_path_flush(struct net_device *dev)
	288	{
	289	struct mesh_path *mpath;
	290	struct mpath_node *node;
	291	struct hlist_node *p;
	292	int i;
	293
	294	for_each_mesh_entry(mesh_paths, p, node, i) {
	295	mpath = node->mpath;
	296	if (mpath->dev == dev)
	297	mesh_path_del(mpath->dst, mpath->dev);
	298	}
	299	}
	300
	301	static void mesh_path_node_reclaim(struct rcu_head *rp)
	302	{
	303	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
	304	struct ieee80211_sub_if_data *sdata =
	305	IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);
	306	if (node->mpath->next_hop)
	307	sta_info_put(node->mpath->next_hop);
	308	atomic_dec(&sdata->u.sta.mpaths);
	309	kfree(node->mpath);
	310	kfree(node);
	311	}
	312
	313	/**
	314	* mesh_path_del - delete a mesh path from the table
	315	*
	316	* @addr: dst address (ETH_ALEN length)
	317	* @dev: local interface
	318	*
	319	* Returns: 0 if succesful
	320	*
	321	* State: if the path is being resolved, the deletion will be postponed until
	322	* the path resolution completes or times out.
	323	*/
	324	int mesh_path_del(u8 addr, struct net_device dev)
325	{
326	struct mesh_path *mpath;
327	struct mpath_node *node;
328	struct hlist_head *bucket;
329	struct hlist_node *n;
330	int hash_idx;
331	int err = 0;
332
333	read_lock(&pathtbl_resize_lock);
334	hash_idx = mesh_table_hash(addr, dev, mesh_paths);
335	bucket = &mesh_paths->hash_buckets[hash_idx];
336
337	spin_lock(&mesh_paths->hashwlock[hash_idx]);
338	hlist_for_each_entry(node, n, bucket, list) {
339	mpath = node->mpath;
340	if (mpath->dev == dev &&
341	memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
342	spin_lock_bh(&mpath->state_lock);
343	if (mpath->flags & MESH_PATH_RESOLVING) {
344	mpath->flags \|= MESH_PATH_DELETE;
345	} else {
346	mpath->flags \|= MESH_PATH_RESOLVING;
347	hlist_del_rcu(&node->list);
348	call_rcu(&node->rcu, mesh_path_node_reclaim);
349	atomic_dec(&mesh_paths->entries);
350	}
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);
513	mesh_path_del(mpath->dst, mpath->dev);
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	}