diff options
| -rw-r--r-- | net/mac80211/mesh_pathtbl.c | 522 |
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); +} |