[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;

	err = -ENOMEM;
	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
	if (!new_mpath)
		goto err_path_alloc;

	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
	if (!new_node)
		goto err_node_alloc;

	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]);

	err = -EEXIST;
	hlist_for_each_entry(node, n, bucket, list) {
		mpath = node->mpath;
		if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
			goto err_exists;
	}

	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;

	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	if (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 0;
		}
		rcu_assign_pointer(mesh_paths, newtbl);
		write_unlock(&pathtbl_resize_lock);

		synchronize_rcu();
		mesh_table_free(oldtbl, false);
	}
	return 0;

err_exists:
	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	read_unlock(&pathtbl_resize_lock);
	kfree(new_node);
err_node_alloc:
	kfree(new_mpath);
err_path_alloc:
	atomic_dec(&sdata->u.sta.mpaths);
	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();
}

/**
 * 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);
	if (free_leafs)
		kfree(mpath);
	kfree(node);
}

static int 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;

	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
	if (new_node == NULL)
		return -ENOMEM;

	node = hlist_entry(p, struct mpath_node, list);
	mpath = node->mpath;
	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]);
	return 0;
}

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
402d7752	161	err = -ENOMEM;
eb2b9311	162	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
402d7752 PE	163	if (!new_mpath)
	164	goto err_path_alloc;
	165
0eb03d5a	166	new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
402d7752 PE	167	if (!new_node)
402d7752 PE	168	goto err_node_alloc;
f84e71a9 PE	169
f84e71a9 PE	170	read_lock(&pathtbl_resize_lock);
eb2b9311 LCC	171	memcpy(new_mpath->dst, dst, ETH_ALEN);
	172	new_mpath->dev = dev;
	173	new_mpath->flags = 0;
	174	skb_queue_head_init(&new_mpath->frame_queue);
eb2b9311 LCC	175	new_node->mpath = new_mpath;
	176	new_mpath->timer.data = (unsigned long) new_mpath;
	177	new_mpath->timer.function = mesh_path_timer;
	178	new_mpath->exp_time = jiffies;
	179	spin_lock_init(&new_mpath->state_lock);
	180	init_timer(&new_mpath->timer);
	181
	182	hash_idx = mesh_table_hash(dst, dev, mesh_paths);
	183	bucket = &mesh_paths->hash_buckets[hash_idx];
	184
	185	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	186
402d7752	187	err = -EEXIST;
eb2b9311 LCC	188	hlist_for_each_entry(node, n, bucket, list) {
eb2b9311 LCC	189	mpath = node->mpath;
402d7752 PE	190	if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
402d7752 PE	191	goto err_exists;
eb2b9311 LCC	192	}
	193
	194	hlist_add_head_rcu(&new_node->list, bucket);
	195	if (atomic_inc_return(&mesh_paths->entries) >=
	196	mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1))
	197	grow = 1;
	198
eb2b9311	199	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
eb2b9311	200	read_unlock(&pathtbl_resize_lock);
402d7752	201	if (grow) {
eb2b9311 LCC	202	struct mesh_table oldtbl, newtbl;
	203
	204	write_lock(&pathtbl_resize_lock);
	205	oldtbl = mesh_paths;
	206	newtbl = mesh_table_grow(mesh_paths);
	207	if (!newtbl) {
	208	write_unlock(&pathtbl_resize_lock);
3282aea9	209	return 0;
eb2b9311 LCC	210	}
eb2b9311 LCC	211	rcu_assign_pointer(mesh_paths, newtbl);
6d6936e2 PE	212	write_unlock(&pathtbl_resize_lock);
6d6936e2 PE	213
eb2b9311 LCC	214	synchronize_rcu();
eb2b9311 LCC	215	mesh_table_free(oldtbl, false);
eb2b9311	216	}
402d7752 PE	217	return 0;
	218
	219	err_exists:
	220	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	221	read_unlock(&pathtbl_resize_lock);
	222	kfree(new_node);
	223	err_node_alloc:
	224	kfree(new_mpath);
	225	err_path_alloc:
	226	atomic_dec(&sdata->u.sta.mpaths);
eb2b9311 LCC	227	return err;
	228	}
	229
	230
	231	/**
	232	* mesh_plink_broken - deactivates paths and sends perr when a link breaks
	233	*
	234	* @sta: broken peer link
	235	*
	236	* This function must be called from the rate control algorithm if enough
	237	* delivery errors suggest that a peer link is no longer usable.
	238	*/
	239	void mesh_plink_broken(struct sta_info *sta)
	240	{
	241	struct mesh_path *mpath;
	242	struct mpath_node *node;
	243	struct hlist_node *p;
d0709a65	244	struct net_device *dev = sta->sdata->dev;
eb2b9311 LCC	245	int i;
	246
	247	rcu_read_lock();
	248	for_each_mesh_entry(mesh_paths, p, node, i) {
	249	mpath = node->mpath;
	250	spin_lock_bh(&mpath->state_lock);
	251	if (mpath->next_hop == sta &&
	252	mpath->flags & MESH_PATH_ACTIVE &&
	253	!(mpath->flags & MESH_PATH_FIXED)) {
	254	mpath->flags &= ~MESH_PATH_ACTIVE;
	255	++mpath->dsn;
	256	spin_unlock_bh(&mpath->state_lock);
	257	mesh_path_error_tx(mpath->dst,
	258	cpu_to_le32(mpath->dsn),
	259	dev->broadcast, dev);
	260	} else
	261	spin_unlock_bh(&mpath->state_lock);
	262	}
	263	rcu_read_unlock();
	264	}
	265
	266	/**
	267	* mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
	268	*
	269	* @sta - mesh peer to match
	270	*
b4e08ea1 LCC	271	* RCU notes: this function is called when a mesh plink transitions from
	272	* PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
	273	* allows path creation. This will happen before the sta can be freed (because
d0709a65 JB	274	* sta_info_destroy() calls this) so any reader in a rcu read block will be
d0709a65 JB	275	* protected against the plink disappearing.
eb2b9311 LCC	276	*/
	277	void mesh_path_flush_by_nexthop(struct sta_info *sta)
	278	{
	279	struct mesh_path *mpath;
	280	struct mpath_node *node;
	281	struct hlist_node *p;
	282	int i;
	283
	284	for_each_mesh_entry(mesh_paths, p, node, i) {
	285	mpath = node->mpath;
	286	if (mpath->next_hop == sta)
cfa22c71	287	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	288	}
	289	}
	290
	291	void mesh_path_flush(struct net_device *dev)
	292	{
	293	struct mesh_path *mpath;
	294	struct mpath_node *node;
	295	struct hlist_node *p;
	296	int i;
	297
	298	for_each_mesh_entry(mesh_paths, p, node, i) {
	299	mpath = node->mpath;
	300	if (mpath->dev == dev)
cfa22c71	301	mesh_path_del(mpath->dst, mpath->dev);
eb2b9311 LCC	302	}
	303	}
	304
	305	static void mesh_path_node_reclaim(struct rcu_head *rp)
	306	{
	307	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
	308	struct ieee80211_sub_if_data *sdata =
	309	IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);
d0709a65	310
89a1ad69	311	del_timer_sync(&node->mpath->timer);
eb2b9311 LCC	312	atomic_dec(&sdata->u.sta.mpaths);
	313	kfree(node->mpath);
	314	kfree(node);
	315	}
	316
	317	/**
	318	* mesh_path_del - delete a mesh path from the table
	319	*
	320	* @addr: dst address (ETH_ALEN length)
	321	* @dev: local interface
	322	*
	323	* Returns: 0 if succesful
eb2b9311	324	*/
cfa22c71	325	int mesh_path_del(u8 addr, struct net_device dev)
eb2b9311 LCC	326	{
	327	struct mesh_path *mpath;
	328	struct mpath_node *node;
	329	struct hlist_head *bucket;
	330	struct hlist_node *n;
	331	int hash_idx;
	332	int err = 0;
	333
	334	read_lock(&pathtbl_resize_lock);
	335	hash_idx = mesh_table_hash(addr, dev, mesh_paths);
	336	bucket = &mesh_paths->hash_buckets[hash_idx];
	337
	338	spin_lock(&mesh_paths->hashwlock[hash_idx]);
	339	hlist_for_each_entry(node, n, bucket, list) {
	340	mpath = node->mpath;
	341	if (mpath->dev == dev &&
	342	memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
	343	spin_lock_bh(&mpath->state_lock);
cfa22c71 LCC	344	mpath->flags \|= MESH_PATH_RESOLVING;
	345	hlist_del_rcu(&node->list);
	346	call_rcu(&node->rcu, mesh_path_node_reclaim);
	347	atomic_dec(&mesh_paths->entries);
eb2b9311 LCC	348	spin_unlock_bh(&mpath->state_lock);
	349	goto enddel;
	350	}
	351	}
	352
	353	err = -ENXIO;
	354	enddel:
	355	spin_unlock(&mesh_paths->hashwlock[hash_idx]);
	356	read_unlock(&pathtbl_resize_lock);
	357	return err;
	358	}
	359
	360	/**
	361	* mesh_path_tx_pending - sends pending frames in a mesh path queue
	362	*
	363	* @mpath: mesh path to activate
	364	*
	365	* Locking: the state_lock of the mpath structure must NOT be held when calling
	366	* this function.
	367	*/
	368	void mesh_path_tx_pending(struct mesh_path *mpath)
	369	{
	370	struct sk_buff *skb;
	371
	372	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
	373	(mpath->flags & MESH_PATH_ACTIVE))
	374	dev_queue_xmit(skb);
	375	}
	376
	377	/**
	378	* mesh_path_discard_frame - discard a frame whose path could not be resolved
	379	*
	380	* @skb: frame to discard
	381	* @dev: network device the frame was to be sent through
	382	*
	383	* If the frame was beign forwarded from another MP, a PERR frame will be sent
	384	* to the precursor.
	385	*
	386	* Locking: the function must me called within a rcu_read_lock region
	387	*/
	388	void mesh_path_discard_frame(struct sk_buff skb, struct net_device dev)
	389	{
	390	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	391	struct mesh_path *mpath;
	392	u32 dsn = 0;
	393
	394	if (skb->pkt_type == PACKET_OTHERHOST) {
	395	struct ieee80211s_hdr *prev_meshhdr;
	396	int mshhdrlen;
	397	u8 ra, da;
	398
	399	prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb);
	400	mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr);
	401	da = skb->data;
	402	ra = MESH_PREQ(skb);
	403	mpath = mesh_path_lookup(da, dev);
	404	if (mpath)
	405	dsn = ++mpath->dsn;
	406	mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev);
	407	}
	408
	409	kfree_skb(skb);
	410	sdata->u.sta.mshstats.dropped_frames_no_route++;
	411	}
412
413	/**
414	* mesh_path_flush_pending - free the pending queue of a mesh path
415	*
416	* @mpath: mesh path whose queue has to be freed
417	*
418	* Locking: the function must me called withing a rcu_read_lock region
419	*/
420	void mesh_path_flush_pending(struct mesh_path *mpath)
421	{
422	struct ieee80211_sub_if_data *sdata;
423	struct sk_buff *skb;
424
425	sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
426
427	while ((skb = skb_dequeue(&mpath->frame_queue)) &&
428	(mpath->flags & MESH_PATH_ACTIVE))
429	mesh_path_discard_frame(skb, mpath->dev);
430	}
431
432	/**
433	* mesh_path_fix_nexthop - force a specific next hop for a mesh path
434	*
435	* @mpath: the mesh path to modify
436	* @next_hop: the next hop to force
437	*
438	* Locking: this function must be called holding mpath->state_lock
439	*/
440	void mesh_path_fix_nexthop(struct mesh_path mpath, struct sta_info next_hop)
441	{
442	spin_lock_bh(&mpath->state_lock);
443	mesh_path_assign_nexthop(mpath, next_hop);
444	mpath->dsn = 0xffff;
445	mpath->metric = 0;
446	mpath->hop_count = 0;
447	mpath->exp_time = 0;
448	mpath->flags \|= MESH_PATH_FIXED;
449	mesh_path_activate(mpath);
450	spin_unlock_bh(&mpath->state_lock);
451	mesh_path_tx_pending(mpath);
452	}
453
454	static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
455	{
456	struct mesh_path *mpath;
457	struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
458	mpath = node->mpath;
459	hlist_del_rcu(p);
eb2b9311 LCC	460	if (free_leafs)
	461	kfree(mpath);
	462	kfree(node);
	463	}
	464
4caf86c6	465	static int mesh_path_node_copy(struct hlist_node p, struct mesh_table newtbl)
eb2b9311 LCC	466	{
	467	struct mesh_path *mpath;
	468	struct mpath_node node, new_node;
	469	u32 hash_idx;
	470
8566dc3f	471	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
00242c40 PE	472	if (new_node == NULL)
	473	return -ENOMEM;
	474
eb2b9311 LCC	475	node = hlist_entry(p, struct mpath_node, list);
eb2b9311 LCC	476	mpath = node->mpath;
eb2b9311 LCC	477	new_node->mpath = mpath;
	478	hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl);
	479	hlist_add_head(&new_node->list,
	480	&newtbl->hash_buckets[hash_idx]);
4caf86c6	481	return 0;
eb2b9311 LCC	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	}