From 5ee68e5b39de5cefecf147c58711f8ab01c21231 Mon Sep 17 00:00:00 2001 From: Javier Cardona Date: Tue, 9 Aug 2011 16:45:08 -0700 Subject: [PATCH] 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 --- include/linux/ieee80211.h | 4 + net/mac80211/ieee80211_i.h | 1 + net/mac80211/mesh.c | 3 +- net/mac80211/mesh.h | 11 ++ net/mac80211/mesh_hwmp.c | 41 +++++-- net/mac80211/mesh_pathtbl.c | 284 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 335 insertions(+), 9 deletions(-) diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index 03cfbf393a63..37f95f2e10f9 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -633,6 +633,10 @@ struct ieee80211_rann_ie { u32 rann_metric; } __attribute__ ((packed)); +enum ieee80211_rann_flags { + RANN_FLAG_IS_GATE = 1 << 0, +}; + #define WLAN_SA_QUERY_TR_ID_LEN 2 struct ieee80211_mgmt { diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index ea7419050846..c204cee1189c 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -514,6 +514,7 @@ struct ieee80211_if_mesh { struct mesh_config mshcfg; u32 mesh_seqnum; bool accepting_plinks; + int num_gates; const u8 *ie; u8 ie_len; enum { diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index ecdde6ce4df0..e120fefb4e40 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -545,7 +545,7 @@ void ieee80211_mesh_quiesce(struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; - /* use atomic bitops in case both timers fire at the same time */ + /* use atomic bitops in case all timers fire at the same time */ if (del_timer_sync(&ifmsh->housekeeping_timer)) set_bit(TMR_RUNNING_HK, &ifmsh->timers_running); @@ -752,6 +752,7 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata) ifmsh->accepting_plinks = true; ifmsh->preq_id = 0; ifmsh->sn = 0; + ifmsh->num_gates = 0; atomic_set(&ifmsh->mpaths, 0); mesh_rmc_init(sdata); ifmsh->last_preq = jiffies; diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h index 3c7d0f8b376a..9d9116e1a9ac 100644 --- a/net/mac80211/mesh.h +++ b/net/mac80211/mesh.h @@ -81,6 +81,7 @@ enum mesh_deferred_task_flags { * @discovery_retries: number of discovery retries * @flags: mesh path flags, as specified on &enum mesh_path_flags * @state_lock: mesh path state lock + * @is_gate: the destination station of this path is a mesh gate * * * The combination of dst and sdata is unique in the mesh path table. Since the @@ -104,6 +105,7 @@ struct mesh_path { u8 discovery_retries; enum mesh_path_flags flags; spinlock_t state_lock; + bool is_gate; }; /** @@ -120,6 +122,9 @@ struct mesh_path { * buckets * @mean_chain_len: maximum average length for the hash buckets' list, if it is * reached, the table will grow + * @known_gates: list of known mesh gates and their mpaths by the station. The + * gate's mpath may or may not be resolved and active. + * * rcu_head: RCU head to free the table */ struct mesh_table { @@ -133,6 +138,8 @@ struct mesh_table { int (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl); int size_order; int mean_chain_len; + struct hlist_head *known_gates; + spinlock_t gates_lock; struct rcu_head rcu_head; }; @@ -236,6 +243,10 @@ void mesh_path_flush(struct ieee80211_sub_if_data *sdata); void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, size_t len); int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata); + +int mesh_path_add_gate(struct mesh_path *mpath); +int mesh_path_send_to_gates(struct mesh_path *mpath); +int mesh_gate_num(struct ieee80211_sub_if_data *sdata); /* Mesh plinks */ void mesh_neighbour_update(u8 *hw_addr, u32 rates, struct ieee80211_sub_if_data *sdata, diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c index abd03473cca4..7b517c46100d 100644 --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -696,6 +696,7 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, u8 *orig_addr; u32 orig_sn, metric; u32 interval = cpu_to_le32(IEEE80211_MESH_RANN_INTERVAL); + bool root_is_gate; ttl = rann->rann_ttl; if (ttl <= 1) { @@ -704,12 +705,19 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, } ttl--; flags = rann->rann_flags; + root_is_gate = !!(flags & RANN_FLAG_IS_GATE); orig_addr = rann->rann_addr; orig_sn = rann->rann_seq; hopcount = rann->rann_hopcount; hopcount++; metric = rann->rann_metric; - mhwmp_dbg("received RANN from %pM\n", orig_addr); + + /* Ignore our own RANNs */ + if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) + return; + + mhwmp_dbg("received RANN from %pM (is_gate=%d)", orig_addr, + root_is_gate); rcu_read_lock(); mpath = mesh_path_lookup(orig_addr, sdata); @@ -721,9 +729,16 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, sdata->u.mesh.mshstats.dropped_frames_no_route++; return; } - mesh_queue_preq(mpath, - PREQ_Q_F_START | PREQ_Q_F_REFRESH); } + + if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) || + time_after(jiffies, mpath->exp_time - 1*HZ)) && + !(mpath->flags & MESH_PATH_FIXED)) { + mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name, + orig_addr); + mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH); + } + if (mpath->sn < orig_sn) { mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr, cpu_to_le32(orig_sn), @@ -733,6 +748,9 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, 0, sdata); mpath->sn = orig_sn; } + if (root_is_gate) + mesh_path_add_gate(mpath); + rcu_read_unlock(); } @@ -994,25 +1012,32 @@ void mesh_path_timer(unsigned long data) { struct mesh_path *mpath = (void *) data; struct ieee80211_sub_if_data *sdata = mpath->sdata; + int ret; if (sdata->local->quiescing) return; spin_lock_bh(&mpath->state_lock); if (mpath->flags & MESH_PATH_RESOLVED || - (!(mpath->flags & MESH_PATH_RESOLVING))) + (!(mpath->flags & MESH_PATH_RESOLVING))) { mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED); - else if (mpath->discovery_retries < max_preq_retries(sdata)) { + spin_unlock_bh(&mpath->state_lock); + } else if (mpath->discovery_retries < max_preq_retries(sdata)) { ++mpath->discovery_retries; mpath->discovery_timeout *= 2; + spin_unlock_bh(&mpath->state_lock); mesh_queue_preq(mpath, 0); } else { mpath->flags = 0; mpath->exp_time = jiffies; - mesh_path_flush_pending(mpath); + spin_unlock_bh(&mpath->state_lock); + if (!mpath->is_gate && mesh_gate_num(sdata) > 0) { + ret = mesh_path_send_to_gates(mpath); + if (ret) + mhwmp_dbg("no gate was reachable"); + } else + mesh_path_flush_pending(mpath); } - - spin_unlock_bh(&mpath->state_lock); } void 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); @@ -688,6 +914,58 @@ void mesh_path_tx_pending(struct mesh_path *mpath) } /** + * 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 * * @skb: frame to discard @@ -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); -- 2.11.0