From 5ee68e5b39de5cefecf147c58711f8ab01c21231 Mon Sep 17 00:00:00 2001 From: Javier Cardona Date: Tue, 9 Aug 2011 16:45:08 -0700 Subject: mac80211: mesh gate implementation In this implementation, a mesh gate is a root node with a certain bit set in its RANN flags. The mpath to this root node is marked as a path to a gate, and added to our list of known gates for this if_mesh. Once a path discovery process fails, we forward the unresolved frames to a known gate. Thanks to Luis Rodriguez for refactoring and bug fix help. Signed-off-by: Javier Cardona Signed-off-by: John W. Linville --- net/mac80211/mesh_pathtbl.c | 284 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 284 insertions(+) (limited to 'net/mac80211/mesh_pathtbl.c') diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index bcf7fee53b2c..75e4b6022b86 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -66,6 +66,8 @@ static inline struct mesh_table *resize_dereference_mpp_paths(void) lockdep_is_held(&pathtbl_resize_lock)); } +static int mesh_gate_add(struct mesh_table *tbl, struct mesh_path *mpath); + /* * CAREFUL -- "tbl" must not be an expression, * in particular not an rcu_dereference(), since @@ -109,6 +111,7 @@ static struct mesh_table *mesh_table_alloc(int size_order) 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; } @@ -124,6 +127,7 @@ 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; @@ -135,6 +139,17 @@ static void mesh_table_free(struct mesh_table *tbl, bool free_leafs) } spin_unlock_bh(&tbl->hashwlock[i]); } + if (free_leafs) { + spin_lock_bh(&tbl->gates_lock); + hlist_for_each_entry_safe(gate, p, 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); } @@ -152,6 +167,7 @@ static int mesh_table_grow(struct mesh_table *oldtbl, 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; @@ -211,6 +227,111 @@ void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta) 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->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, *cp_skb; + struct sk_buff_head gateq, failq; + unsigned long flags; + int num_skbs; + + BUG_ON(gate_mpath == from_mpath); + BUG_ON(!gate_mpath->next_hop); + + __skb_queue_head_init(&gateq); + __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); + + num_skbs = skb_queue_len(&failq); + + while (num_skbs--) { + skb = __skb_dequeue(&failq); + if (copy) + cp_skb = skb_copy(skb, GFP_ATOMIC); + + prepare_for_gate(skb, gate_mpath->dst, gate_mpath); + __skb_queue_tail(&gateq, skb); + + if (copy && cp_skb) + __skb_queue_tail(&failq, cp_skb); + } + + spin_lock_irqsave(&gate_mpath->frame_queue.lock, flags); + skb_queue_splice(&gateq, &gate_mpath->frame_queue); + mpath_dbg("Mpath queue for gate %pM has %d frames\n", + gate_mpath->dst, + skb_queue_len(&gate_mpath->frame_queue)); + spin_unlock_irqrestore(&gate_mpath->frame_queue.lock, flags); + + 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); +} + /** * mesh_path_lookup - look up a path in the mesh path table @@ -310,6 +431,109 @@ struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data return NULL; } +static void mesh_gate_node_reclaim(struct rcu_head *rp) +{ + struct mpath_node *node = container_of(rp, struct mpath_node, rcu); + kfree(node); +} + +/** + * mesh_gate_add - mark mpath as path to a mesh gate and add to known_gates + * @mesh_tbl: table which contains known_gates list + * @mpath: mpath to known mesh gate + * + * Returns: 0 on success + * + */ +static int mesh_gate_add(struct mesh_table *tbl, struct mesh_path *mpath) +{ + struct mpath_node *gate, *new_gate; + struct hlist_node *n; + int err; + + rcu_read_lock(); + tbl = rcu_dereference(tbl); + + hlist_for_each_entry_rcu(gate, n, 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); + rcu_read_unlock(); + mpath_dbg("Mesh path (%s): Recorded new gate: %pM. %d known gates\n", + mpath->sdata->name, mpath->dst, + mpath->sdata->u.mesh.num_gates); + return 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 + * + * Returns: 0 on success + * + * Locking: must be called inside rcu_read_lock() section + */ +static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath) +{ + struct mpath_node *gate; + struct hlist_node *p, *q; + + tbl = rcu_dereference(tbl); + + hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list) + if (gate->mpath == mpath) { + spin_lock_bh(&tbl->gates_lock); + hlist_del_rcu(&gate->list); + call_rcu(&gate->rcu, mesh_gate_node_reclaim); + spin_unlock_bh(&tbl->gates_lock); + mpath->sdata->u.mesh.num_gates--; + mpath->is_gate = false; + mpath_dbg("Mesh path (%s): Deleted gate: %pM. " + "%d known gates\n", mpath->sdata->name, + mpath->dst, mpath->sdata->u.mesh.num_gates); + break; + } + + return 0; +} + +/** + * + * 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) +{ + return mesh_gate_add(mesh_paths, mpath); +} + +/** + * 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 * @addr: destination address of the path (ETH_ALEN length) @@ -655,6 +879,8 @@ int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata) if (mpath->sdata == sdata && memcmp(addr, mpath->dst, ETH_ALEN) == 0) { spin_lock_bh(&mpath->state_lock); + if (mpath->is_gate) + mesh_gate_del(tbl, mpath); mpath->flags |= MESH_PATH_RESOLVING; hlist_del_rcu(&node->list); call_rcu(&node->rcu, mesh_path_node_reclaim); @@ -687,6 +913,58 @@ void mesh_path_tx_pending(struct mesh_path *mpath) &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 hlist_node *n; + 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, n, known_gates, list) { + if (gate->mpath->sdata != sdata) + continue; + + if (gate->mpath->flags & MESH_PATH_ACTIVE) { + mpath_dbg("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("Not forwarding %p\n", gate->mpath); + mpath_dbg("flags %x\n", gate->mpath->flags); + } + } + + hlist_for_each_entry_rcu(gate, n, known_gates, list) + if (gate->mpath->sdata == sdata) { + mpath_dbg("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 * @@ -804,6 +1082,9 @@ int mesh_pathtbl_init(void) 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); + INIT_HLIST_HEAD(tbl_path->known_gates); + tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER); if (!tbl_mpp) { @@ -813,6 +1094,9 @@ int mesh_pathtbl_init(void) tbl_mpp->free_node = &mesh_path_node_free; tbl_mpp->copy_node = &mesh_path_node_copy; tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN; + /* XXX: not needed */ + tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC); + INIT_HLIST_HEAD(tbl_mpp->known_gates); /* Need no locking since this is during init */ RCU_INIT_POINTER(mesh_paths, tbl_path); -- cgit v1.2.3-59-g8ed1b