/* * 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/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 */ /* This lock will have the grow table function as writer and add / delete nodes * as readers. When reading the table (i.e. doing lookups) we are well protected * by RCU */ static DEFINE_RWLOCK(pathtbl_resize_lock); /** * * mesh_path_assign_nexthop - update mesh path next hop * * @mpath: mesh path to update * @sta: next hop to assign * * Locking: mpath->state_lock must be held when calling this function */ void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta) { rcu_assign_pointer(mpath->next_hop, sta); } /** * mesh_path_lookup - look up a path in the mesh path table * @dst: hardware address (ETH_ALEN length) of destination * @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 sucess * * 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 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_KERNEL); if (!new_mpath) goto err_path_alloc; new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL); 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; spin_unlock(&mesh_paths->hashwlock[hash_idx]); read_unlock(&pathtbl_resize_lock); if (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 0; } rcu_assign_pointer(mesh_paths, newtbl); write_unlock(&pathtbl_resize_lock); synchronize_rcu(); mesh_table_free(oldtbl, false); } 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; } int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata) { 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_KERNEL); if (!new_mpath) goto err_path_alloc; new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL); 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) { 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 0; } rcu_assign_pointer(mpp_paths, newtbl); write_unlock(&pathtbl_resize_lock); synchronize_rcu(); mesh_table_free(oldtbl, false); } 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) { 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->dsn; spin_unlock_bh(&mpath->state_lock); mesh_path_error_tx(mpath->dst, cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 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 succesful */ 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: 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 * @sdata: network subif 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 ieee80211_sub_if_data *sdata) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct mesh_path *mpath; u32 dsn = 0; if (memcmp(hdr->addr4, sdata->dev->dev_addr, ETH_ALEN) != 0) { u8 *ra, *da; da = hdr->addr3; ra = hdr->addr2; mpath = mesh_path_lookup(da, sdata); if (mpath) dsn = ++mpath->dsn; mesh_path_error_tx(skb->data, cpu_to_le32(dsn), 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->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); 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); }