Initial import

1 files changed, 1142 insertions, 0 deletions

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
new file mode 100644
index 000000000..b890e225a
--- /dev/null
+++ b/net/mac80211/mesh_pathtbl.c
@@ -0,0 +1,1142 @@
+/*
+ * Copyright (c) 2008, 2009 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/random.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <net/mac80211.h>
+#include "wme.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
+
+static inline bool mpath_expired(struct mesh_path *mpath)
+{
+	return (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 __rcu *mesh_paths;
+static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
+
+int mesh_paths_generation;
+int mpp_paths_generation;
+
+/* This lock will have the grow table function as writer and add / delete nodes
+ * as readers. RCU provides sufficient protection only when reading the table
+ * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
+ * the read lock or we risk operating on an old table.  The write lock is only
+ * needed when modifying the number of buckets a table.
+ */
+static DEFINE_RWLOCK(pathtbl_resize_lock);
+
+
+static inline struct mesh_table *resize_dereference_mesh_paths(void)
+{
+	return rcu_dereference_protected(mesh_paths,
+		lockdep_is_held(&pathtbl_resize_lock));
+}
+
+static inline struct mesh_table *resize_dereference_mpp_paths(void)
+{
+	return rcu_dereference_protected(mpp_paths,
+		lockdep_is_held(&pathtbl_resize_lock));
+}
+
+/*
+ * CAREFUL -- "tbl" must not be an expression,
+ * in particular not an rcu_dereference(), since
+ * it's used twice. So it is illegal to do
+ *	for_each_mesh_entry(rcu_dereference(...), ...)
+ */
+#define for_each_mesh_entry(tbl, node, i) \
+	for (i = 0; i <= tbl->hash_mask; i++) \
+		hlist_for_each_entry_rcu(node, &tbl->hash_buckets[i], list)
+
+
+static struct mesh_table *mesh_table_alloc(int size_order)
+{
+	int i;
+	struct mesh_table *newtbl;
+
+	newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
+	if (!newtbl)
+		return NULL;
+
+	newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
+			(1 << size_order), GFP_ATOMIC);
+
+	if (!newtbl->hash_buckets) {
+		kfree(newtbl);
+		return NULL;
+	}
+
+	newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
+			(1 << size_order), GFP_ATOMIC);
+	if (!newtbl->hashwlock) {
+		kfree(newtbl->hash_buckets);
+		kfree(newtbl);
+		return NULL;
+	}
+
+	newtbl->size_order = size_order;
+	newtbl->hash_mask = (1 << size_order) - 1;
+	atomic_set(&newtbl->entries,  0);
+	get_random_bytes(&newtbl->hash_rnd,
+			sizeof(newtbl->hash_rnd));
+	for (i = 0; i <= newtbl->hash_mask; i++)
+		spin_lock_init(&newtbl->hashwlock[i]);
+	spin_lock_init(&newtbl->gates_lock);
+
+	return newtbl;
+}
+
+static void __mesh_table_free(struct mesh_table *tbl)
+{
+	kfree(tbl->hash_buckets);
+	kfree(tbl->hashwlock);
+	kfree(tbl);
+}
+
+static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
+{
+	struct hlist_head *mesh_hash;
+	struct hlist_node *p, *q;
+	struct mpath_node *gate;
+	int i;
+
+	mesh_hash = tbl->hash_buckets;
+	for (i = 0; i <= tbl->hash_mask; i++) {
+		spin_lock_bh(&tbl->hashwlock[i]);
+		hlist_for_each_safe(p, q, &mesh_hash[i]) {
+			tbl->free_node(p, free_leafs);
+			atomic_dec(&tbl->entries);
+		}
+		spin_unlock_bh(&tbl->hashwlock[i]);
+	}
+	if (free_leafs) {
+		spin_lock_bh(&tbl->gates_lock);
+		hlist_for_each_entry_safe(gate, q,
+					 tbl->known_gates, list) {
+			hlist_del(&gate->list);
+			kfree(gate);
+		}
+		kfree(tbl->known_gates);
+		spin_unlock_bh(&tbl->gates_lock);
+	}
+
+	__mesh_table_free(tbl);
+}
+
+static int mesh_table_grow(struct mesh_table *oldtbl,
+			   struct mesh_table *newtbl)
+{
+	struct hlist_head *oldhash;
+	struct hlist_node *p, *q;
+	int i;
+
+	if (atomic_read(&oldtbl->entries)
+			< oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
+		return -EAGAIN;
+
+	newtbl->free_node = oldtbl->free_node;
+	newtbl->mean_chain_len = oldtbl->mean_chain_len;
+	newtbl->copy_node = oldtbl->copy_node;
+	newtbl->known_gates = oldtbl->known_gates;
+	atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
+
+	oldhash = oldtbl->hash_buckets;
+	for (i = 0; i <= oldtbl->hash_mask; i++)
+		hlist_for_each(p, &oldhash[i])
+			if (oldtbl->copy_node(p, newtbl) < 0)
+				goto errcopy;
+
+	return 0;
+
+errcopy:
+	for (i = 0; i <= newtbl->hash_mask; i++) {
+		hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
+			oldtbl->free_node(p, 0);
+	}
+	return -ENOMEM;
+}
+
+static u32 mesh_table_hash(const u8 *addr, struct ieee80211_sub_if_data *sdata,
+			   struct mesh_table *tbl)
+{
+	/* Use last four bytes of hw addr and interface index as hash index */
+	return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex,
+			    tbl->hash_rnd) & tbl->hash_mask;
+}
+
+
+/**
+ *
+ * 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)
+{
+	struct sk_buff *skb;
+	struct ieee80211_hdr *hdr;
+	unsigned long flags;
+
+	rcu_assign_pointer(mpath->next_hop, sta);
+
+	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
+	skb_queue_walk(&mpath->frame_queue, skb) {
+		hdr = (struct ieee80211_hdr *) skb->data;
+		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
+		memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
+		ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
+	}
+
+	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
+}
+
+static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
+			     struct mesh_path *gate_mpath)
+{
+	struct ieee80211_hdr *hdr;
+	struct ieee80211s_hdr *mshdr;
+	int mesh_hdrlen, hdrlen;
+	char *next_hop;
+
+	hdr = (struct ieee80211_hdr *) skb->data;
+	hdrlen = ieee80211_hdrlen(hdr->frame_control);
+	mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
+
+	if (!(mshdr->flags & MESH_FLAGS_AE)) {
+		/* size of the fixed part of the mesh header */
+		mesh_hdrlen = 6;
+
+		/* make room for the two extended addresses */
+		skb_push(skb, 2 * ETH_ALEN);
+		memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
+
+		hdr = (struct ieee80211_hdr *) skb->data;
+
+		/* we preserve the previous mesh header and only add
+		 * the new addreses */
+		mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
+		mshdr->flags = MESH_FLAGS_AE_A5_A6;
+		memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
+		memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
+	}
+
+	/* update next hop */
+	hdr = (struct ieee80211_hdr *) skb->data;
+	rcu_read_lock();
+	next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
+	memcpy(hdr->addr1, next_hop, ETH_ALEN);
+	rcu_read_unlock();
+	memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
+	memcpy(hdr->addr3, dst_addr, ETH_ALEN);
+}
+
+/**
+ *
+ * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
+ *
+ * This function is used to transfer or copy frames from an unresolved mpath to
+ * a gate mpath.  The function also adds the Address Extension field and
+ * updates the next hop.
+ *
+ * If a frame already has an Address Extension field, only the next hop and
+ * destination addresses are updated.
+ *
+ * The gate mpath must be an active mpath with a valid mpath->next_hop.
+ *
+ * @mpath: An active mpath the frames will be sent to (i.e. the gate)
+ * @from_mpath: The failed mpath
+ * @copy: When true, copy all the frames to the new mpath queue.  When false,
+ * move them.
+ */
+static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
+				    struct mesh_path *from_mpath,
+				    bool copy)
+{
+	struct sk_buff *skb, *fskb, *tmp;
+	struct sk_buff_head failq;
+	unsigned long flags;
+
+	if (WARN_ON(gate_mpath == from_mpath))
+		return;
+	if (WARN_ON(!gate_mpath->next_hop))
+		return;
+
+	__skb_queue_head_init(&failq);
+
+	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
+	skb_queue_splice_init(&from_mpath->frame_queue, &failq);
+	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
+
+	skb_queue_walk_safe(&failq, fskb, tmp) {
+		if (skb_queue_len(&gate_mpath->frame_queue) >=
+				  MESH_FRAME_QUEUE_LEN) {
+			mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
+			break;
+		}
+
+		skb = skb_copy(fskb, GFP_ATOMIC);
+		if (WARN_ON(!skb))
+			break;
+
+		prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
+		skb_queue_tail(&gate_mpath->frame_queue, skb);
+
+		if (copy)
+			continue;
+
+		__skb_unlink(fskb, &failq);
+		kfree_skb(fskb);
+	}
+
+	mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
+		  gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
+
+	if (!copy)
+		return;
+
+	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
+	skb_queue_splice(&failq, &from_mpath->frame_queue);
+	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
+}
+
+
+static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
+				      struct ieee80211_sub_if_data *sdata)
+{
+	struct mesh_path *mpath;
+	struct hlist_head *bucket;
+	struct mpath_node *node;
+
+	bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
+	hlist_for_each_entry_rcu(node, bucket, list) {
+		mpath = node->mpath;
+		if (mpath->sdata == sdata &&
+		    ether_addr_equal(dst, mpath->dst)) {
+			if (mpath_expired(mpath)) {
+				spin_lock_bh(&mpath->state_lock);
+				mpath->flags &= ~MESH_PATH_ACTIVE;
+				spin_unlock_bh(&mpath->state_lock);
+			}
+			return mpath;
+		}
+	}
+	return NULL;
+}
+
+/**
+ * mesh_path_lookup - look up a path in the mesh path table
+ * @sdata: local subif
+ * @dst: hardware address (ETH_ALEN length) of destination
+ *
+ * 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(struct ieee80211_sub_if_data *sdata, const u8 *dst)
+{
+	return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
+}
+
+struct mesh_path *
+mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
+{
+	return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
+}
+
+
+/**
+ * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
+ * @idx: index
+ * @sdata: local subif, 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(struct ieee80211_sub_if_data *sdata, int idx)
+{
+	struct mesh_table *tbl = rcu_dereference(mesh_paths);
+	struct mpath_node *node;
+	int i;
+	int j = 0;
+
+	for_each_mesh_entry(tbl, node, i) {
+		if (sdata && node->mpath->sdata != sdata)
+			continue;
+		if (j++ == idx) {
+			if (mpath_expired(node->mpath)) {
+				spin_lock_bh(&node->mpath->state_lock);
+				node->mpath->flags &= ~MESH_PATH_ACTIVE;
+				spin_unlock_bh(&node->mpath->state_lock);
+			}
+			return node->mpath;
+		}
+	}
+
+	return NULL;
+}
+
+/**
+ * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
+ * @idx: index
+ * @sdata: local subif, or NULL for all entries
+ *
+ * Returns: pointer to the proxy path structure, or NULL if not found.
+ *
+ * Locking: must be called within a read rcu section.
+ */
+struct mesh_path *
+mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
+{
+	struct mesh_table *tbl = rcu_dereference(mpp_paths);
+	struct mpath_node *node;
+	int i;
+	int j = 0;
+
+	for_each_mesh_entry(tbl, node, i) {
+		if (sdata && node->mpath->sdata != sdata)
+			continue;
+		if (j++ == idx)
+			return node->mpath;
+	}
+
+	return NULL;
+}
+
+/**
+ * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
+ * @mpath: gate path to add to table
+ */
+int mesh_path_add_gate(struct mesh_path *mpath)
+{
+	struct mesh_table *tbl;
+	struct mpath_node *gate, *new_gate;
+	int err;
+
+	rcu_read_lock();
+	tbl = rcu_dereference(mesh_paths);
+
+	hlist_for_each_entry_rcu(gate, tbl->known_gates, list)
+		if (gate->mpath == mpath) {
+			err = -EEXIST;
+			goto err_rcu;
+		}
+
+	new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
+	if (!new_gate) {
+		err = -ENOMEM;
+		goto err_rcu;
+	}
+
+	mpath->is_gate = true;
+	mpath->sdata->u.mesh.num_gates++;
+	new_gate->mpath = mpath;
+	spin_lock_bh(&tbl->gates_lock);
+	hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
+	spin_unlock_bh(&tbl->gates_lock);
+	mpath_dbg(mpath->sdata,
+		  "Mesh path: Recorded new gate: %pM. %d known gates\n",
+		  mpath->dst, mpath->sdata->u.mesh.num_gates);
+	err = 0;
+err_rcu:
+	rcu_read_unlock();
+	return err;
+}
+
+/**
+ * mesh_gate_del - remove a mesh gate from the list of known gates
+ * @tbl: table which holds our list of known gates
+ * @mpath: gate mpath
+ *
+ * Locking: must be called inside rcu_read_lock() section
+ */
+static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
+{
+	struct mpath_node *gate;
+	struct hlist_node *q;
+
+	hlist_for_each_entry_safe(gate, q, tbl->known_gates, list) {
+		if (gate->mpath != mpath)
+			continue;
+		spin_lock_bh(&tbl->gates_lock);
+		hlist_del_rcu(&gate->list);
+		kfree_rcu(gate, rcu);
+		spin_unlock_bh(&tbl->gates_lock);
+		mpath->sdata->u.mesh.num_gates--;
+		mpath->is_gate = false;
+		mpath_dbg(mpath->sdata,
+			  "Mesh path: Deleted gate: %pM. %d known gates\n",
+			  mpath->dst, mpath->sdata->u.mesh.num_gates);
+		break;
+	}
+}
+
+/**
+ * mesh_gate_num - number of gates known to this interface
+ * @sdata: subif data
+ */
+int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
+{
+	return sdata->u.mesh.num_gates;
+}
+
+/**
+ * mesh_path_add - allocate and add a new path to the mesh path table
+ * @dst: destination address of the path (ETH_ALEN length)
+ * @sdata: local subif
+ *
+ * Returns: 0 on success
+ *
+ * State: the initial state of the new path is set to 0
+ */
+struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
+				const u8 *dst)
+{
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct ieee80211_local *local = sdata->local;
+	struct mesh_table *tbl;
+	struct mesh_path *mpath, *new_mpath;
+	struct mpath_node *node, *new_node;
+	struct hlist_head *bucket;
+	int grow = 0;
+	int err;
+	u32 hash_idx;
+
+	if (ether_addr_equal(dst, sdata->vif.addr))
+		/* never add ourselves as neighbours */
+		return ERR_PTR(-ENOTSUPP);
+
+	if (is_multicast_ether_addr(dst))
+		return ERR_PTR(-ENOTSUPP);
+
+	if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
+		return ERR_PTR(-ENOSPC);
+
+	read_lock_bh(&pathtbl_resize_lock);
+	tbl = resize_dereference_mesh_paths();
+
+	hash_idx = mesh_table_hash(dst, sdata, tbl);
+	bucket = &tbl->hash_buckets[hash_idx];
+
+	spin_lock(&tbl->hashwlock[hash_idx]);
+
+	hlist_for_each_entry(node, bucket, list) {
+		mpath = node->mpath;
+		if (mpath->sdata == sdata &&
+		    ether_addr_equal(dst, mpath->dst))
+			goto found;
+	}
+
+	err = -ENOMEM;
+	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
+	if (!new_mpath)
+		goto err_path_alloc;
+
+	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
+	if (!new_node)
+		goto err_node_alloc;
+
+	memcpy(new_mpath->dst, dst, ETH_ALEN);
+	eth_broadcast_addr(new_mpath->rann_snd_addr);
+	new_mpath->is_root = false;
+	new_mpath->sdata = sdata;
+	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);
+
+	hlist_add_head_rcu(&new_node->list, bucket);
+	if (atomic_inc_return(&tbl->entries) >=
+	    tbl->mean_chain_len * (tbl->hash_mask + 1))
+		grow = 1;
+
+	mesh_paths_generation++;
+
+	if (grow) {
+		set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
+		ieee80211_queue_work(&local->hw, &sdata->work);
+	}
+	mpath = new_mpath;
+found:
+	spin_unlock(&tbl->hashwlock[hash_idx]);
+	read_unlock_bh(&pathtbl_resize_lock);
+	return mpath;
+
+err_node_alloc:
+	kfree(new_mpath);
+err_path_alloc:
+	atomic_dec(&sdata->u.mesh.mpaths);
+	spin_unlock(&tbl->hashwlock[hash_idx]);
+	read_unlock_bh(&pathtbl_resize_lock);
+	return ERR_PTR(err);
+}
+
+static void mesh_table_free_rcu(struct rcu_head *rcu)
+{
+	struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
+
+	mesh_table_free(tbl, false);
+}
+
+void mesh_mpath_table_grow(void)
+{
+	struct mesh_table *oldtbl, *newtbl;
+
+	write_lock_bh(&pathtbl_resize_lock);
+	oldtbl = resize_dereference_mesh_paths();
+	newtbl = mesh_table_alloc(oldtbl->size_order + 1);
+	if (!newtbl)
+		goto out;
+	if (mesh_table_grow(oldtbl, newtbl) < 0) {
+		__mesh_table_free(newtbl);
+		goto out;
+	}
+	rcu_assign_pointer(mesh_paths, newtbl);
+
+	call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
+
+ out:
+	write_unlock_bh(&pathtbl_resize_lock);
+}
+
+void mesh_mpp_table_grow(void)
+{
+	struct mesh_table *oldtbl, *newtbl;
+
+	write_lock_bh(&pathtbl_resize_lock);
+	oldtbl = resize_dereference_mpp_paths();
+	newtbl = mesh_table_alloc(oldtbl->size_order + 1);
+	if (!newtbl)
+		goto out;
+	if (mesh_table_grow(oldtbl, newtbl) < 0) {
+		__mesh_table_free(newtbl);
+		goto out;
+	}
+	rcu_assign_pointer(mpp_paths, newtbl);
+	call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
+
+ out:
+	write_unlock_bh(&pathtbl_resize_lock);
+}
+
+int mpp_path_add(struct ieee80211_sub_if_data *sdata,
+		 const u8 *dst, const u8 *mpp)
+{
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct ieee80211_local *local = sdata->local;
+	struct mesh_table *tbl;
+	struct mesh_path *mpath, *new_mpath;
+	struct mpath_node *node, *new_node;
+	struct hlist_head *bucket;
+	int grow = 0;
+	int err = 0;
+	u32 hash_idx;
+
+	if (ether_addr_equal(dst, sdata->vif.addr))
+		/* never add ourselves as neighbours */
+		return -ENOTSUPP;
+
+	if (is_multicast_ether_addr(dst))
+		return -ENOTSUPP;
+
+	err = -ENOMEM;
+	new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
+	if (!new_mpath)
+		goto err_path_alloc;
+
+	new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
+	if (!new_node)
+		goto err_node_alloc;
+
+	read_lock_bh(&pathtbl_resize_lock);
+	memcpy(new_mpath->dst, dst, ETH_ALEN);
+	memcpy(new_mpath->mpp, mpp, ETH_ALEN);
+	new_mpath->sdata = sdata;
+	new_mpath->flags = 0;
+	skb_queue_head_init(&new_mpath->frame_queue);
+	new_node->mpath = new_mpath;
+	init_timer(&new_mpath->timer);
+	new_mpath->exp_time = jiffies;
+	spin_lock_init(&new_mpath->state_lock);
+
+	tbl = resize_dereference_mpp_paths();
+
+	hash_idx = mesh_table_hash(dst, sdata, tbl);
+	bucket = &tbl->hash_buckets[hash_idx];
+
+	spin_lock(&tbl->hashwlock[hash_idx]);
+
+	err = -EEXIST;
+	hlist_for_each_entry(node, bucket, list) {
+		mpath = node->mpath;
+		if (mpath->sdata == sdata &&
+		    ether_addr_equal(dst, mpath->dst))
+			goto err_exists;
+	}
+
+	hlist_add_head_rcu(&new_node->list, bucket);
+	if (atomic_inc_return(&tbl->entries) >=
+	    tbl->mean_chain_len * (tbl->hash_mask + 1))
+		grow = 1;
+
+	spin_unlock(&tbl->hashwlock[hash_idx]);
+	read_unlock_bh(&pathtbl_resize_lock);
+
+	mpp_paths_generation++;
+
+	if (grow) {
+		set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
+		ieee80211_queue_work(&local->hw, &sdata->work);
+	}
+	return 0;
+
+err_exists:
+	spin_unlock(&tbl->hashwlock[hash_idx]);
+	read_unlock_bh(&pathtbl_resize_lock);
+	kfree(new_node);
+err_node_alloc:
+	kfree(new_mpath);
+err_path_alloc:
+	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_table *tbl;
+	static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+	struct mesh_path *mpath;
+	struct mpath_node *node;
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	int i;
+
+	rcu_read_lock();
+	tbl = rcu_dereference(mesh_paths);
+	for_each_mesh_entry(tbl, node, i) {
+		mpath = node->mpath;
+		if (rcu_access_pointer(mpath->next_hop) == sta &&
+		    mpath->flags & MESH_PATH_ACTIVE &&
+		    !(mpath->flags & MESH_PATH_FIXED)) {
+			spin_lock_bh(&mpath->state_lock);
+			mpath->flags &= ~MESH_PATH_ACTIVE;
+			++mpath->sn;
+			spin_unlock_bh(&mpath->state_lock);
+			mesh_path_error_tx(sdata,
+				sdata->u.mesh.mshcfg.element_ttl,
+				mpath->dst, mpath->sn,
+				WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
+		}
+	}
+	rcu_read_unlock();
+}
+
+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 = node->mpath->sdata;
+
+	del_timer_sync(&node->mpath->timer);
+	atomic_dec(&sdata->u.mesh.mpaths);
+	kfree(node->mpath);
+	kfree(node);
+}
+
+/* needs to be called with the corresponding hashwlock taken */
+static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
+{
+	struct mesh_path *mpath;
+	mpath = node->mpath;
+	spin_lock(&mpath->state_lock);
+	mpath->flags |= MESH_PATH_RESOLVING;
+	if (mpath->is_gate)
+		mesh_gate_del(tbl, mpath);
+	hlist_del_rcu(&node->list);
+	call_rcu(&node->rcu, mesh_path_node_reclaim);
+	spin_unlock(&mpath->state_lock);
+	atomic_dec(&tbl->entries);
+}
+
+/**
+ * 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_table *tbl;
+	struct mesh_path *mpath;
+	struct mpath_node *node;
+	int i;
+
+	rcu_read_lock();
+	read_lock_bh(&pathtbl_resize_lock);
+	tbl = resize_dereference_mesh_paths();
+	for_each_mesh_entry(tbl, node, i) {
+		mpath = node->mpath;
+		if (rcu_access_pointer(mpath->next_hop) == sta) {
+			spin_lock(&tbl->hashwlock[i]);
+			__mesh_path_del(tbl, node);
+			spin_unlock(&tbl->hashwlock[i]);
+		}
+	}
+	read_unlock_bh(&pathtbl_resize_lock);
+	rcu_read_unlock();
+}
+
+static void table_flush_by_iface(struct mesh_table *tbl,
+				 struct ieee80211_sub_if_data *sdata)
+{
+	struct mesh_path *mpath;
+	struct mpath_node *node;
+	int i;
+
+	WARN_ON(!rcu_read_lock_held());
+	for_each_mesh_entry(tbl, node, i) {
+		mpath = node->mpath;
+		if (mpath->sdata != sdata)
+			continue;
+		spin_lock_bh(&tbl->hashwlock[i]);
+		__mesh_path_del(tbl, node);
+		spin_unlock_bh(&tbl->hashwlock[i]);
+	}
+}
+
+/**
+ * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
+ *
+ * This function deletes both mesh paths as well as mesh portal paths.
+ *
+ * @sdata: interface data to match
+ *
+ */
+void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
+{
+	struct mesh_table *tbl;
+
+	rcu_read_lock();
+	read_lock_bh(&pathtbl_resize_lock);
+	tbl = resize_dereference_mesh_paths();
+	table_flush_by_iface(tbl, sdata);
+	tbl = resize_dereference_mpp_paths();
+	table_flush_by_iface(tbl, sdata);
+	read_unlock_bh(&pathtbl_resize_lock);
+	rcu_read_unlock();
+}
+
+/**
+ * mesh_path_del - delete a mesh path from the table
+ *
+ * @addr: dst address (ETH_ALEN length)
+ * @sdata: local subif
+ *
+ * Returns: 0 if successful
+ */
+int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
+{
+	struct mesh_table *tbl;
+	struct mesh_path *mpath;
+	struct mpath_node *node;
+	struct hlist_head *bucket;
+	int hash_idx;
+	int err = 0;
+
+	read_lock_bh(&pathtbl_resize_lock);
+	tbl = resize_dereference_mesh_paths();
+	hash_idx = mesh_table_hash(addr, sdata, tbl);
+	bucket = &tbl->hash_buckets[hash_idx];
+
+	spin_lock(&tbl->hashwlock[hash_idx]);
+	hlist_for_each_entry(node, bucket, list) {
+		mpath = node->mpath;
+		if (mpath->sdata == sdata &&
+		    ether_addr_equal(addr, mpath->dst)) {
+			__mesh_path_del(tbl, node);
+			goto enddel;
+		}
+	}
+
+	err = -ENXIO;
+enddel:
+	mesh_paths_generation++;
+	spin_unlock(&tbl->hashwlock[hash_idx]);
+	read_unlock_bh(&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)
+{
+	if (mpath->flags & MESH_PATH_ACTIVE)
+		ieee80211_add_pending_skbs(mpath->sdata->local,
+				&mpath->frame_queue);
+}
+
+/**
+ * mesh_path_send_to_gates - sends pending frames to all known mesh gates
+ *
+ * @mpath: mesh path whose queue will be emptied
+ *
+ * If there is only one gate, the frames are transferred from the failed mpath
+ * queue to that gate's queue.  If there are more than one gates, the frames
+ * are copied from each gate to the next.  After frames are copied, the
+ * mpath queues are emptied onto the transmission queue.
+ */
+int mesh_path_send_to_gates(struct mesh_path *mpath)
+{
+	struct ieee80211_sub_if_data *sdata = mpath->sdata;
+	struct mesh_table *tbl;
+	struct mesh_path *from_mpath = mpath;
+	struct mpath_node *gate = NULL;
+	bool copy = false;
+	struct hlist_head *known_gates;
+
+	rcu_read_lock();
+	tbl = rcu_dereference(mesh_paths);
+	known_gates = tbl->known_gates;
+	rcu_read_unlock();
+
+	if (!known_gates)
+		return -EHOSTUNREACH;
+
+	hlist_for_each_entry_rcu(gate, known_gates, list) {
+		if (gate->mpath->sdata != sdata)
+			continue;
+
+		if (gate->mpath->flags & MESH_PATH_ACTIVE) {
+			mpath_dbg(sdata, "Forwarding to %pM\n", gate->mpath->dst);
+			mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
+			from_mpath = gate->mpath;
+			copy = true;
+		} else {
+			mpath_dbg(sdata,
+				  "Not forwarding %p (flags %#x)\n",
+				  gate->mpath, gate->mpath->flags);
+		}
+	}
+
+	hlist_for_each_entry_rcu(gate, known_gates, list)
+		if (gate->mpath->sdata == sdata) {
+			mpath_dbg(sdata, "Sending to %pM\n", gate->mpath->dst);
+			mesh_path_tx_pending(gate->mpath);
+		}
+
+	return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
+}
+
+/**
+ * mesh_path_discard_frame - discard a frame whose path could not be resolved
+ *
+ * @skb: frame to discard
+ * @sdata: network subif the frame was to be sent through
+ *
+ * Locking: the function must me called within a rcu_read_lock region
+ */
+void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
+			     struct sk_buff *skb)
+{
+	kfree_skb(skb);
+	sdata->u.mesh.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 within a rcu_read_lock region
+ */
+void mesh_path_flush_pending(struct mesh_path *mpath)
+{
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
+		mesh_path_discard_frame(mpath->sdata, skb);
+}
+
+/**
+ * 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->sn = 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) {
+		del_timer_sync(&mpath->timer);
+		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->sdata, newtbl);
+	hlist_add_head(&new_node->list,
+			&newtbl->hash_buckets[hash_idx]);
+	return 0;
+}
+
+int mesh_pathtbl_init(void)
+{
+	struct mesh_table *tbl_path, *tbl_mpp;
+	int ret;
+
+	tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
+	if (!tbl_path)
+		return -ENOMEM;
+	tbl_path->free_node = &mesh_path_node_free;
+	tbl_path->copy_node = &mesh_path_node_copy;
+	tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
+	tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
+	if (!tbl_path->known_gates) {
+		ret = -ENOMEM;
+		goto free_path;
+	}
+	INIT_HLIST_HEAD(tbl_path->known_gates);
+
+
+	tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
+	if (!tbl_mpp) {
+		ret = -ENOMEM;
+		goto free_path;
+	}
+	tbl_mpp->free_node = &mesh_path_node_free;
+	tbl_mpp->copy_node = &mesh_path_node_copy;
+	tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
+	tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
+	if (!tbl_mpp->known_gates) {
+		ret = -ENOMEM;
+		goto free_mpp;
+	}
+	INIT_HLIST_HEAD(tbl_mpp->known_gates);
+
+	/* Need no locking since this is during init */
+	RCU_INIT_POINTER(mesh_paths, tbl_path);
+	RCU_INIT_POINTER(mpp_paths, tbl_mpp);
+
+	return 0;
+
+free_mpp:
+	mesh_table_free(tbl_mpp, true);
+free_path:
+	mesh_table_free(tbl_path, true);
+	return ret;
+}
+
+void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
+{
+	struct mesh_table *tbl;
+	struct mesh_path *mpath;
+	struct mpath_node *node;
+	int i;
+
+	rcu_read_lock();
+	tbl = rcu_dereference(mesh_paths);
+	for_each_mesh_entry(tbl, node, i) {
+		if (node->mpath->sdata != sdata)
+			continue;
+		mpath = node->mpath;
+		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
+		    (!(mpath->flags & MESH_PATH_FIXED)) &&
+		     time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
+			mesh_path_del(mpath->sdata, mpath->dst);
+	}
+	rcu_read_unlock();
+}
+
+void mesh_pathtbl_unregister(void)
+{
+	/* no need for locking during exit path */
+	mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
+	mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
+}