diff options
Diffstat (limited to 'kernel/net/mac80211/mesh_pathtbl.c')
| -rw-r--r-- | kernel/net/mac80211/mesh_pathtbl.c | 1142 |
1 files changed, 1142 insertions, 0 deletions
diff --git a/kernel/net/mac80211/mesh_pathtbl.c b/kernel/net/mac80211/mesh_pathtbl.c new file mode 100644 index 000000000..b890e225a --- /dev/null +++ b/kernel/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); +} |