/* * 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/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; static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */ int mesh_paths_generation; static void __mesh_table_free(struct mesh_table *tbl) { kfree(tbl->hash_buckets); kfree(tbl->hashwlock); kfree(tbl); } void mesh_table_free(struct mesh_table *tbl, bool free_leafs) { struct hlist_head *mesh_hash; struct hlist_node *p, *q; int i; mesh_hash = tbl->hash_buckets; for (i = 0; i <= tbl->hash_mask; i++) { spin_lock(&tbl->hashwlock[i]); hlist_for_each_safe(p, q, &mesh_hash[i]) { tbl->free_node(p, free_leafs); atomic_dec(&tbl->entries); } spin_unlock(&tbl->hashwlock[i]); } __mesh_table_free(tbl); } static struct mesh_table *mesh_table_grow(struct mesh_table *tbl) { struct mesh_table *newtbl; struct hlist_head *oldhash; struct hlist_node *p, *q; int i; if (atomic_read(&tbl->entries) < tbl->mean_chain_len * (tbl->hash_mask + 1)) goto endgrow; newtbl = mesh_table_alloc(tbl->size_order + 1); if (!newtbl) goto endgrow; newtbl->free_node = tbl->free_node; newtbl->mean_chain_len = tbl->mean_chain_len; newtbl->copy_node = tbl->copy_node; atomic_set(&newtbl->entries, atomic_read(&tbl->entries)); oldhash = tbl->hash_buckets; for (i = 0; i <= tbl->hash_mask; i++) hlist_for_each(p, &oldhash[i]) if (tbl->copy_node(p, newtbl) < 0) goto errcopy; return newtbl; errcopy: for (i = 0; i <= newtbl->hash_mask; i++) { hlist_for_each_safe(p, q, &newtbl->hash_buckets[i]) tbl->free_node(p, 0); } __mesh_table_free(newtbl); endgrow: return NULL; } /* 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) { struct sk_buff *skb; struct ieee80211_hdr *hdr; struct sk_buff_head tmpq; unsigned long flags; rcu_assign_pointer(mpath->next_hop, sta); __skb_queue_head_init(&tmpq); spin_lock_irqsave(&mpath->frame_queue.lock, flags); while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) { hdr = (struct ieee80211_hdr *) skb->data; memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN); __skb_queue_tail(&tmpq, skb); } skb_queue_splice(&tmpq, &mpath->frame_queue); spin_unlock_irqrestore(&mpath->frame_queue.lock, flags); } /** * mesh_path_lookup - look up a path in the mesh path table * @dst: hardware address (ETH_ALEN length) of destination * @sdata: local subif * * 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 ieee80211_sub_if_data *sdata) { 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, sdata, tbl)]; hlist_for_each_entry_rcu(node, n, bucket, list) { mpath = node->mpath; if (mpath->sdata == sdata && 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; } struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata) { struct mesh_path *mpath; struct hlist_node *n; struct hlist_head *bucket; struct mesh_table *tbl; struct mpath_node *node; tbl = rcu_dereference(mpp_paths); bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)]; hlist_for_each_entry_rcu(node, n, bucket, list) { mpath = node->mpath; if (mpath->sdata == sdata && 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 * @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(int idx, struct ieee80211_sub_if_data *sdata) { struct mpath_node *node; struct hlist_node *p; int i; int j = 0; for_each_mesh_entry(mesh_paths, p, node, i) { if (sdata && node->mpath->sdata != sdata) 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) * @sdata: local subif * * Returns: 0 on success * * State: the initial state of the new path is set to 0 */ int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct ieee80211_local *local = sdata->local; 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, sdata->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.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0) return -ENOSPC; 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(&pathtbl_resize_lock); memcpy(new_mpath->dst, dst, ETH_ALEN); 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); hash_idx = mesh_table_hash(dst, sdata, mesh_paths); bucket = &mesh_paths->hash_buckets[hash_idx]; spin_lock(&mesh_paths->hashwlock[hash_idx]); err = -EEXIST; hlist_for_each_entry(node, n, bucket, list) { mpath = node->mpath; if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0) goto err_exists; } 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; mesh_paths_generation++; spin_unlock(&mesh_paths->hashwlock[hash_idx]); read_unlock(&pathtbl_resize_lock); if (grow) { set_bit(MESH_WORK_GROW_MPATH_TABLE, &ifmsh->wrkq_flags); ieee80211_queue_work(&local->hw, &ifmsh->work); } return 0; err_exists: spin_unlock(&mesh_paths->hashwlock[hash_idx]); read_unlock(&pathtbl_resize_lock); kfree(new_node); err_node_alloc: kfree(new_mpath); err_path_alloc: atomic_dec(&sdata->u.mesh.mpaths); return err; } void mesh_mpath_table_grow(void) { 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; } rcu_assign_pointer(mesh_paths, newtbl); write_unlock(&pathtbl_resize_lock); synchronize_rcu(); mesh_table_free(oldtbl, false); } void mesh_mpp_table_grow(void) { struct mesh_table *oldtbl, *newtbl; write_lock(&pathtbl_resize_lock); oldtbl = mpp_paths; newtbl = mesh_table_grow(mpp_paths); if (!newtbl) { write_unlock(&pathtbl_resize_lock); return; } rcu_assign_pointer(mpp_paths, newtbl); write_unlock(&pathtbl_resize_lock); synchronize_rcu(); mesh_table_free(oldtbl, false); } int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct ieee80211_local *local = sdata->local; 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, sdata->dev->dev_addr, ETH_ALEN) == 0) /* 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(&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; new_mpath->exp_time = jiffies; spin_lock_init(&new_mpath->state_lock); hash_idx = mesh_table_hash(dst, sdata, mpp_paths); bucket = &mpp_paths->hash_buckets[hash_idx]; spin_lock(&mpp_paths->hashwlock[hash_idx]); err = -EEXIST; hlist_for_each_entry(node, n, bucket, list) { mpath = node->mpath; if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0) goto err_exists; } hlist_add_head_rcu(&new_node->list, bucket); if (atomic_inc_return(&mpp_paths->entries) >= mpp_paths->mean_chain_len * (mpp_paths->hash_mask + 1)) grow = 1; spin_unlock(&mpp_paths->hashwlock[hash_idx]); read_unlock(&pathtbl_resize_lock); if (grow) { set_bit(MESH_WORK_GROW_MPP_TABLE, &ifmsh->wrkq_flags); ieee80211_queue_work(&local->hw, &ifmsh->work); } return 0; err_exists: spin_unlock(&mpp_paths->hashwlock[hash_idx]); read_unlock(&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) { static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; struct mesh_path *mpath; struct mpath_node *node; struct hlist_node *p; struct ieee80211_sub_if_data *sdata = sta->sdata; 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->sn; spin_unlock_bh(&mpath->state_lock); mesh_path_error_tx(MESH_TTL, mpath->dst, cpu_to_le32(mpath->sn), cpu_to_le16(PERR_RCODE_DEST_UNREACH), bcast, sdata); } 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 * 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->sdata); } } void mesh_path_flush(struct ieee80211_sub_if_data *sdata) { 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->sdata == sdata) mesh_path_del(mpath->dst, mpath->sdata); } } 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); } /** * 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(u8 *addr, struct ieee80211_sub_if_data *sdata) { 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, sdata, 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->sdata == sdata && 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: mesh_paths_generation++; 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) { if (mpath->flags & MESH_PATH_ACTIVE) ieee80211_add_pending_skbs(mpath->sdata->local, &mpath->frame_queue); } /** * 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 * * If the frame was being forwarded from another MP, a PERR frame will be sent * to the precursor. The precursor's address (i.e. the previous hop) was saved * in addr1 of the frame-to-be-forwarded, and would only be overwritten once * the destination is successfully resolved. * * Locking: the function must me called within a rcu_read_lock region */ void mesh_path_discard_frame(struct sk_buff *skb, struct ieee80211_sub_if_data *sdata) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct mesh_path *mpath; u32 sn = 0; if (memcmp(hdr->addr4, sdata->dev->dev_addr, ETH_ALEN) != 0) { u8 *ra, *da; da = hdr->addr3; ra = hdr->addr1; mpath = mesh_path_lookup(da, sdata); if (mpath) sn = ++mpath->sn; mesh_path_error_tx(MESH_TTL, skb->data, cpu_to_le32(sn), cpu_to_le16(PERR_RCODE_NO_ROUTE), ra, sdata); } 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 withing 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)) && (mpath->flags & MESH_PATH_ACTIVE)) mesh_path_discard_frame(skb, mpath->sdata); } /** * 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) 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) { mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER); if (!mesh_paths) return -ENOMEM; mesh_paths->free_node = &mesh_path_node_free; mesh_paths->copy_node = &mesh_path_node_copy; mesh_paths->mean_chain_len = MEAN_CHAIN_LEN; mpp_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER); if (!mpp_paths) { mesh_table_free(mesh_paths, true); return -ENOMEM; } mpp_paths->free_node = &mesh_path_node_free; mpp_paths->copy_node = &mesh_path_node_copy; mpp_paths->mean_chain_len = MEAN_CHAIN_LEN; return 0; } void mesh_path_expire(struct ieee80211_sub_if_data *sdata) { 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->sdata != sdata) 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->sdata); } else spin_unlock_bh(&mpath->state_lock); } read_unlock(&pathtbl_resize_lock); } void mesh_pathtbl_unregister(void) { mesh_table_free(mesh_paths, true); mesh_table_free(mpp_paths, true); }