1 files changed, 516 insertions, 0 deletions

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
new file mode 100644
index 000000000000..5845dc21ce85
--- /dev/null
+++ b/net/mac80211/mesh_pathtbl.c
@@ -0,0 +1,516 @@
+/*
+ * 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;
+
+        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->sdata->dev;
+        int i;
+
+        rcu_read_lock();
+        for_each_mesh_entry(mesh_paths, p, node, i) {
+                mpath = node->mpath;
+                spin_lock_bh(&mpath->state_lock);
+                if (mpath->next_hop == sta &&
+                    mpath->flags & MESH_PATH_ACTIVE &&
+                    !(mpath->flags & MESH_PATH_FIXED)) {
+                        mpath->flags &= ~MESH_PATH_ACTIVE;
+                        ++mpath->dsn;
+                        spin_unlock_bh(&mpath->state_lock);
+                        mesh_path_error_tx(mpath->dst,
+                                        cpu_to_le32(mpath->dsn),
+                                        dev->broadcast, dev);
+                } else
+                spin_unlock_bh(&mpath->state_lock);
+        }
+        rcu_read_unlock();
+}
+EXPORT_SYMBOL(mesh_plink_broken);
+
+/**
+ * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
+ *
+ * @sta - mesh peer to match
+ *
+ * RCU notes: this function is called when a mesh plink transitions from
+ * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
+ * allows path creation. This will happen before the sta can be freed (because
+ * sta_info_destroy() calls this) so any reader in a rcu read block will be
+ * protected against the plink disappearing.
+ */
+void mesh_path_flush_by_nexthop(struct sta_info *sta)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node;
+        struct hlist_node *p;
+        int i;
+
+        for_each_mesh_entry(mesh_paths, p, node, i) {
+                mpath = node->mpath;
+                if (mpath->next_hop == sta)
+                        mesh_path_del(mpath->dst, mpath->dev);
+        }
+}
+
+void mesh_path_flush(struct net_device *dev)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node;
+        struct hlist_node *p;
+        int i;
+
+        for_each_mesh_entry(mesh_paths, p, node, i) {
+                mpath = node->mpath;
+                if (mpath->dev == dev)
+                        mesh_path_del(mpath->dst, mpath->dev);
+        }
+}
+
+static void mesh_path_node_reclaim(struct rcu_head *rp)
+{
+        struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
+        struct ieee80211_sub_if_data *sdata =
+                IEEE80211_DEV_TO_SUB_IF(node->mpath->dev);
+
+        del_timer_sync(&node->mpath->timer);
+        atomic_dec(&sdata->u.sta.mpaths);
+        kfree(node->mpath);
+        kfree(node);
+}
+
+/**
+ * mesh_path_del - delete a mesh path from the table
+ *
+ * @addr: dst address (ETH_ALEN length)
+ * @dev: local interface
+ *
+ * Returns: 0 if succesful
+ */
+int mesh_path_del(u8 *addr, struct net_device *dev)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node;
+        struct hlist_head *bucket;
+        struct hlist_node *n;
+        int hash_idx;
+        int err = 0;
+
+        read_lock(&pathtbl_resize_lock);
+        hash_idx = mesh_table_hash(addr, dev, mesh_paths);
+        bucket = &mesh_paths->hash_buckets[hash_idx];
+
+        spin_lock(&mesh_paths->hashwlock[hash_idx]);
+        hlist_for_each_entry(node, n, bucket, list) {
+                mpath = node->mpath;
+                if (mpath->dev == dev &&
+                                memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
+                        spin_lock_bh(&mpath->state_lock);
+                        mpath->flags |= MESH_PATH_RESOLVING;
+                        hlist_del_rcu(&node->list);
+                        call_rcu(&node->rcu, mesh_path_node_reclaim);
+                        atomic_dec(&mesh_paths->entries);
+                        spin_unlock_bh(&mpath->state_lock);
+                        goto enddel;
+                }
+        }
+
+        err = -ENXIO;
+enddel:
+        spin_unlock(&mesh_paths->hashwlock[hash_idx]);
+        read_unlock(&pathtbl_resize_lock);
+        return err;
+}
+
+/**
+ * mesh_path_tx_pending - sends pending frames in a mesh path queue
+ *
+ * @mpath: mesh path to activate
+ *
+ * Locking: the state_lock of the mpath structure must NOT be held when calling
+ * this function.
+ */
+void mesh_path_tx_pending(struct mesh_path *mpath)
+{
+        struct sk_buff *skb;
+
+        while ((skb = skb_dequeue(&mpath->frame_queue)) &&
+                        (mpath->flags & MESH_PATH_ACTIVE))
+                dev_queue_xmit(skb);
+}
+
+/**
+ * mesh_path_discard_frame - discard a frame whose path could not be resolved
+ *
+ * @skb: frame to discard
+ * @dev: network device the frame was to be sent through
+ *
+ * If the frame was beign forwarded from another MP, a PERR frame will be sent
+ * to the precursor.
+ *
+ * Locking: the function must me called within a rcu_read_lock region
+ */
+void mesh_path_discard_frame(struct sk_buff *skb, struct net_device *dev)
+{
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct mesh_path *mpath;
+        u32 dsn = 0;
+
+        if (skb->pkt_type == PACKET_OTHERHOST) {
+                struct ieee80211s_hdr *prev_meshhdr;
+                int mshhdrlen;
+                u8 *ra, *da;
+
+                prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb);
+                mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr);
+                da = skb->data;
+                ra = MESH_PREQ(skb);
+                mpath = mesh_path_lookup(da, dev);
+                if (mpath)
+                        dsn = ++mpath->dsn;
+                mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev);
+        }
+
+        kfree_skb(skb);
+        sdata->u.sta.mshstats.dropped_frames_no_route++;
+}
+
+/**
+ * mesh_path_flush_pending - free the pending queue of a mesh path
+ *
+ * @mpath: mesh path whose queue has to be freed
+ *
+ * Locking: the function must me called withing a rcu_read_lock region
+ */
+void mesh_path_flush_pending(struct mesh_path *mpath)
+{
+        struct ieee80211_sub_if_data *sdata;
+        struct sk_buff *skb;
+
+        sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
+
+        while ((skb = skb_dequeue(&mpath->frame_queue)) &&
+                        (mpath->flags & MESH_PATH_ACTIVE))
+                mesh_path_discard_frame(skb, mpath->dev);
+}
+
+/**
+ * mesh_path_fix_nexthop - force a specific next hop for a mesh path
+ *
+ * @mpath: the mesh path to modify
+ * @next_hop: the next hop to force
+ *
+ * Locking: this function must be called holding mpath->state_lock
+ */
+void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
+{
+        spin_lock_bh(&mpath->state_lock);
+        mesh_path_assign_nexthop(mpath, next_hop);
+        mpath->dsn = 0xffff;
+        mpath->metric = 0;
+        mpath->hop_count = 0;
+        mpath->exp_time = 0;
+        mpath->flags |= MESH_PATH_FIXED;
+        mesh_path_activate(mpath);
+        spin_unlock_bh(&mpath->state_lock);
+        mesh_path_tx_pending(mpath);
+}
+
+static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
+        mpath = node->mpath;
+        hlist_del_rcu(p);
+        synchronize_rcu();
+        if (free_leafs)
+                kfree(mpath);
+        kfree(node);
+}
+
+static void mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node, *new_node;
+        u32 hash_idx;
+
+        node = hlist_entry(p, struct mpath_node, list);
+        mpath = node->mpath;
+        new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
+        new_node->mpath = mpath;
+        hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl);
+        hlist_add_head(&new_node->list,
+                        &newtbl->hash_buckets[hash_idx]);
+}
+
+int mesh_pathtbl_init(void)
+{
+        mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
+        mesh_paths->free_node = &mesh_path_node_free;
+        mesh_paths->copy_node = &mesh_path_node_copy;
+        mesh_paths->mean_chain_len = MEAN_CHAIN_LEN;
+        if (!mesh_paths)
+                return -ENOMEM;
+        return 0;
+}
+
+void mesh_path_expire(struct net_device *dev)
+{
+        struct mesh_path *mpath;
+        struct mpath_node *node;
+        struct hlist_node *p;
+        int i;
+
+        read_lock(&pathtbl_resize_lock);
+        for_each_mesh_entry(mesh_paths, p, node, i) {
+                if (node->mpath->dev != dev)
+                        continue;
+                mpath = node->mpath;
+                spin_lock_bh(&mpath->state_lock);
+                if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
+                    (!(mpath->flags & MESH_PATH_FIXED)) &&
+                        time_after(jiffies,
+                         mpath->exp_time + MESH_PATH_EXPIRE)) {
+                        spin_unlock_bh(&mpath->state_lock);
+                        mesh_path_del(mpath->dst, mpath->dev);
+                } else
+                        spin_unlock_bh(&mpath->state_lock);
+        }
+        read_unlock(&pathtbl_resize_lock);
+}
+
+void mesh_pathtbl_unregister(void)
+{
+        mesh_table_free(mesh_paths, true);
+}