/* * 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); }