1 files changed, 522 insertions, 0 deletions
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
new file mode 100644
index 00000000000..37094942e72
--- /dev/null
+++ b/net/mac80211/mesh_pathtbl.c
@@ -0,0 +1,522 @@
+/*
+ * 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();
+}
+
+/**
+ * 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);
+}