Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
[linux-2.6.git] / net / mac80211 / mesh_pathtbl.c
1 /*
2  * Copyright (c) 2008, 2009 open80211s Ltd.
3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9
10 #include <linux/etherdevice.h>
11 #include <linux/list.h>
12 #include <linux/random.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/string.h>
16 #include <net/mac80211.h>
17 #include "wme.h"
18 #include "ieee80211_i.h"
19 #include "mesh.h"
20
21 #ifdef CONFIG_MAC80211_VERBOSE_MPATH_DEBUG
22 #define mpath_dbg(fmt, args...) printk(KERN_DEBUG fmt, ##args)
23 #else
24 #define mpath_dbg(fmt, args...) do { (void)(0); } while (0)
25 #endif
26
27 /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
28 #define INIT_PATHS_SIZE_ORDER   2
29
30 /* Keep the mean chain length below this constant */
31 #define MEAN_CHAIN_LEN          2
32
33 #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
34                                 time_after(jiffies, mpath->exp_time) && \
35                                 !(mpath->flags & MESH_PATH_FIXED))
36
37 struct mpath_node {
38         struct hlist_node list;
39         struct rcu_head rcu;
40         /* This indirection allows two different tables to point to the same
41          * mesh_path structure, useful when resizing
42          */
43         struct mesh_path *mpath;
44 };
45
46 static struct mesh_table __rcu *mesh_paths;
47 static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
48
49 int mesh_paths_generation;
50
51 /* This lock will have the grow table function as writer and add / delete nodes
52  * as readers. RCU provides sufficient protection only when reading the table
53  * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
54  * the read lock or we risk operating on an old table.  The write lock is only
55  * needed when modifying the number of buckets a table.
56  */
57 static DEFINE_RWLOCK(pathtbl_resize_lock);
58
59
60 static inline struct mesh_table *resize_dereference_mesh_paths(void)
61 {
62         return rcu_dereference_protected(mesh_paths,
63                 lockdep_is_held(&pathtbl_resize_lock));
64 }
65
66 static inline struct mesh_table *resize_dereference_mpp_paths(void)
67 {
68         return rcu_dereference_protected(mpp_paths,
69                 lockdep_is_held(&pathtbl_resize_lock));
70 }
71
72 /*
73  * CAREFUL -- "tbl" must not be an expression,
74  * in particular not an rcu_dereference(), since
75  * it's used twice. So it is illegal to do
76  *      for_each_mesh_entry(rcu_dereference(...), ...)
77  */
78 #define for_each_mesh_entry(tbl, p, node, i) \
79         for (i = 0; i <= tbl->hash_mask; i++) \
80                 hlist_for_each_entry_rcu(node, p, &tbl->hash_buckets[i], list)
81
82
83 static struct mesh_table *mesh_table_alloc(int size_order)
84 {
85         int i;
86         struct mesh_table *newtbl;
87
88         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
89         if (!newtbl)
90                 return NULL;
91
92         newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
93                         (1 << size_order), GFP_ATOMIC);
94
95         if (!newtbl->hash_buckets) {
96                 kfree(newtbl);
97                 return NULL;
98         }
99
100         newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
101                         (1 << size_order), GFP_ATOMIC);
102         if (!newtbl->hashwlock) {
103                 kfree(newtbl->hash_buckets);
104                 kfree(newtbl);
105                 return NULL;
106         }
107
108         newtbl->size_order = size_order;
109         newtbl->hash_mask = (1 << size_order) - 1;
110         atomic_set(&newtbl->entries,  0);
111         get_random_bytes(&newtbl->hash_rnd,
112                         sizeof(newtbl->hash_rnd));
113         for (i = 0; i <= newtbl->hash_mask; i++)
114                 spin_lock_init(&newtbl->hashwlock[i]);
115         spin_lock_init(&newtbl->gates_lock);
116
117         return newtbl;
118 }
119
120 static void __mesh_table_free(struct mesh_table *tbl)
121 {
122         kfree(tbl->hash_buckets);
123         kfree(tbl->hashwlock);
124         kfree(tbl);
125 }
126
127 static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
128 {
129         struct hlist_head *mesh_hash;
130         struct hlist_node *p, *q;
131         struct mpath_node *gate;
132         int i;
133
134         mesh_hash = tbl->hash_buckets;
135         for (i = 0; i <= tbl->hash_mask; i++) {
136                 spin_lock_bh(&tbl->hashwlock[i]);
137                 hlist_for_each_safe(p, q, &mesh_hash[i]) {
138                         tbl->free_node(p, free_leafs);
139                         atomic_dec(&tbl->entries);
140                 }
141                 spin_unlock_bh(&tbl->hashwlock[i]);
142         }
143         if (free_leafs) {
144                 spin_lock_bh(&tbl->gates_lock);
145                 hlist_for_each_entry_safe(gate, p, q,
146                                          tbl->known_gates, list) {
147                         hlist_del(&gate->list);
148                         kfree(gate);
149                 }
150                 kfree(tbl->known_gates);
151                 spin_unlock_bh(&tbl->gates_lock);
152         }
153
154         __mesh_table_free(tbl);
155 }
156
157 static int mesh_table_grow(struct mesh_table *oldtbl,
158                            struct mesh_table *newtbl)
159 {
160         struct hlist_head *oldhash;
161         struct hlist_node *p, *q;
162         int i;
163
164         if (atomic_read(&oldtbl->entries)
165                         < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
166                 return -EAGAIN;
167
168         newtbl->free_node = oldtbl->free_node;
169         newtbl->mean_chain_len = oldtbl->mean_chain_len;
170         newtbl->copy_node = oldtbl->copy_node;
171         newtbl->known_gates = oldtbl->known_gates;
172         atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
173
174         oldhash = oldtbl->hash_buckets;
175         for (i = 0; i <= oldtbl->hash_mask; i++)
176                 hlist_for_each(p, &oldhash[i])
177                         if (oldtbl->copy_node(p, newtbl) < 0)
178                                 goto errcopy;
179
180         return 0;
181
182 errcopy:
183         for (i = 0; i <= newtbl->hash_mask; i++) {
184                 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
185                         oldtbl->free_node(p, 0);
186         }
187         return -ENOMEM;
188 }
189
190 static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
191                            struct mesh_table *tbl)
192 {
193         /* Use last four bytes of hw addr and interface index as hash index */
194         return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
195                 & tbl->hash_mask;
196 }
197
198
199 /**
200  *
201  * mesh_path_assign_nexthop - update mesh path next hop
202  *
203  * @mpath: mesh path to update
204  * @sta: next hop to assign
205  *
206  * Locking: mpath->state_lock must be held when calling this function
207  */
208 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
209 {
210         struct sk_buff *skb;
211         struct ieee80211_hdr *hdr;
212         struct sk_buff_head tmpq;
213         unsigned long flags;
214
215         rcu_assign_pointer(mpath->next_hop, sta);
216
217         __skb_queue_head_init(&tmpq);
218
219         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
220
221         while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
222                 hdr = (struct ieee80211_hdr *) skb->data;
223                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
224                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
225                 __skb_queue_tail(&tmpq, skb);
226         }
227
228         skb_queue_splice(&tmpq, &mpath->frame_queue);
229         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
230 }
231
232 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
233                              struct mesh_path *gate_mpath)
234 {
235         struct ieee80211_hdr *hdr;
236         struct ieee80211s_hdr *mshdr;
237         int mesh_hdrlen, hdrlen;
238         char *next_hop;
239
240         hdr = (struct ieee80211_hdr *) skb->data;
241         hdrlen = ieee80211_hdrlen(hdr->frame_control);
242         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
243
244         if (!(mshdr->flags & MESH_FLAGS_AE)) {
245                 /* size of the fixed part of the mesh header */
246                 mesh_hdrlen = 6;
247
248                 /* make room for the two extended addresses */
249                 skb_push(skb, 2 * ETH_ALEN);
250                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
251
252                 hdr = (struct ieee80211_hdr *) skb->data;
253
254                 /* we preserve the previous mesh header and only add
255                  * the new addreses */
256                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
257                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
258                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
259                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
260         }
261
262         /* update next hop */
263         hdr = (struct ieee80211_hdr *) skb->data;
264         rcu_read_lock();
265         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
266         memcpy(hdr->addr1, next_hop, ETH_ALEN);
267         rcu_read_unlock();
268         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
269         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
270 }
271
272 /**
273  *
274  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
275  *
276  * This function is used to transfer or copy frames from an unresolved mpath to
277  * a gate mpath.  The function also adds the Address Extension field and
278  * updates the next hop.
279  *
280  * If a frame already has an Address Extension field, only the next hop and
281  * destination addresses are updated.
282  *
283  * The gate mpath must be an active mpath with a valid mpath->next_hop.
284  *
285  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
286  * @from_mpath: The failed mpath
287  * @copy: When true, copy all the frames to the new mpath queue.  When false,
288  * move them.
289  */
290 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
291                                     struct mesh_path *from_mpath,
292                                     bool copy)
293 {
294         struct sk_buff *skb, *cp_skb = NULL;
295         struct sk_buff_head gateq, failq;
296         unsigned long flags;
297         int num_skbs;
298
299         BUG_ON(gate_mpath == from_mpath);
300         BUG_ON(!gate_mpath->next_hop);
301
302         __skb_queue_head_init(&gateq);
303         __skb_queue_head_init(&failq);
304
305         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
306         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
307         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
308
309         num_skbs = skb_queue_len(&failq);
310
311         while (num_skbs--) {
312                 skb = __skb_dequeue(&failq);
313                 if (copy) {
314                         cp_skb = skb_copy(skb, GFP_ATOMIC);
315                         if (cp_skb)
316                                 __skb_queue_tail(&failq, cp_skb);
317                 }
318
319                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
320                 __skb_queue_tail(&gateq, skb);
321         }
322
323         spin_lock_irqsave(&gate_mpath->frame_queue.lock, flags);
324         skb_queue_splice(&gateq, &gate_mpath->frame_queue);
325         mpath_dbg("Mpath queue for gate %pM has %d frames\n",
326                         gate_mpath->dst,
327                         skb_queue_len(&gate_mpath->frame_queue));
328         spin_unlock_irqrestore(&gate_mpath->frame_queue.lock, flags);
329
330         if (!copy)
331                 return;
332
333         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
334         skb_queue_splice(&failq, &from_mpath->frame_queue);
335         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
336 }
337
338
339 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, u8 *dst,
340                                           struct ieee80211_sub_if_data *sdata)
341 {
342         struct mesh_path *mpath;
343         struct hlist_node *n;
344         struct hlist_head *bucket;
345         struct mpath_node *node;
346
347         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
348         hlist_for_each_entry_rcu(node, n, bucket, list) {
349                 mpath = node->mpath;
350                 if (mpath->sdata == sdata &&
351                                 compare_ether_addr(dst, mpath->dst) == 0) {
352                         if (MPATH_EXPIRED(mpath)) {
353                                 spin_lock_bh(&mpath->state_lock);
354                                 mpath->flags &= ~MESH_PATH_ACTIVE;
355                                 spin_unlock_bh(&mpath->state_lock);
356                         }
357                         return mpath;
358                 }
359         }
360         return NULL;
361 }
362
363 /**
364  * mesh_path_lookup - look up a path in the mesh path table
365  * @dst: hardware address (ETH_ALEN length) of destination
366  * @sdata: local subif
367  *
368  * Returns: pointer to the mesh path structure, or NULL if not found
369  *
370  * Locking: must be called within a read rcu section.
371  */
372 struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
373 {
374         return mpath_lookup(rcu_dereference(mesh_paths), dst, sdata);
375 }
376
377 struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
378 {
379         return mpath_lookup(rcu_dereference(mpp_paths), dst, sdata);
380 }
381
382
383 /**
384  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
385  * @idx: index
386  * @sdata: local subif, or NULL for all entries
387  *
388  * Returns: pointer to the mesh path structure, or NULL if not found.
389  *
390  * Locking: must be called within a read rcu section.
391  */
392 struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
393 {
394         struct mesh_table *tbl = rcu_dereference(mesh_paths);
395         struct mpath_node *node;
396         struct hlist_node *p;
397         int i;
398         int j = 0;
399
400         for_each_mesh_entry(tbl, p, node, i) {
401                 if (sdata && node->mpath->sdata != sdata)
402                         continue;
403                 if (j++ == idx) {
404                         if (MPATH_EXPIRED(node->mpath)) {
405                                 spin_lock_bh(&node->mpath->state_lock);
406                                 node->mpath->flags &= ~MESH_PATH_ACTIVE;
407                                 spin_unlock_bh(&node->mpath->state_lock);
408                         }
409                         return node->mpath;
410                 }
411         }
412
413         return NULL;
414 }
415
416 /**
417  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
418  * @mpath: gate path to add to table
419  */
420 int mesh_path_add_gate(struct mesh_path *mpath)
421 {
422         struct mesh_table *tbl;
423         struct mpath_node *gate, *new_gate;
424         struct hlist_node *n;
425         int err;
426
427         rcu_read_lock();
428         tbl = rcu_dereference(mesh_paths);
429
430         hlist_for_each_entry_rcu(gate, n, tbl->known_gates, list)
431                 if (gate->mpath == mpath) {
432                         err = -EEXIST;
433                         goto err_rcu;
434                 }
435
436         new_gate = kzalloc(sizeof(struct mpath_node), GFP_ATOMIC);
437         if (!new_gate) {
438                 err = -ENOMEM;
439                 goto err_rcu;
440         }
441
442         mpath->is_gate = true;
443         mpath->sdata->u.mesh.num_gates++;
444         new_gate->mpath = mpath;
445         spin_lock_bh(&tbl->gates_lock);
446         hlist_add_head_rcu(&new_gate->list, tbl->known_gates);
447         spin_unlock_bh(&tbl->gates_lock);
448         rcu_read_unlock();
449         mpath_dbg("Mesh path (%s): Recorded new gate: %pM. %d known gates\n",
450                   mpath->sdata->name, mpath->dst,
451                   mpath->sdata->u.mesh.num_gates);
452         return 0;
453 err_rcu:
454         rcu_read_unlock();
455         return err;
456 }
457
458 /**
459  * mesh_gate_del - remove a mesh gate from the list of known gates
460  * @tbl: table which holds our list of known gates
461  * @mpath: gate mpath
462  *
463  * Returns: 0 on success
464  *
465  * Locking: must be called inside rcu_read_lock() section
466  */
467 static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
468 {
469         struct mpath_node *gate;
470         struct hlist_node *p, *q;
471
472         hlist_for_each_entry_safe(gate, p, q, tbl->known_gates, list)
473                 if (gate->mpath == mpath) {
474                         spin_lock_bh(&tbl->gates_lock);
475                         hlist_del_rcu(&gate->list);
476                         kfree_rcu(gate, rcu);
477                         spin_unlock_bh(&tbl->gates_lock);
478                         mpath->sdata->u.mesh.num_gates--;
479                         mpath->is_gate = false;
480                         mpath_dbg("Mesh path (%s): Deleted gate: %pM. "
481                                   "%d known gates\n", mpath->sdata->name,
482                                   mpath->dst, mpath->sdata->u.mesh.num_gates);
483                         break;
484                 }
485
486         return 0;
487 }
488
489 /**
490  * mesh_gate_num - number of gates known to this interface
491  * @sdata: subif data
492  */
493 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
494 {
495         return sdata->u.mesh.num_gates;
496 }
497
498 /**
499  * mesh_path_add - allocate and add a new path to the mesh path table
500  * @addr: destination address of the path (ETH_ALEN length)
501  * @sdata: local subif
502  *
503  * Returns: 0 on success
504  *
505  * State: the initial state of the new path is set to 0
506  */
507 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
508 {
509         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
510         struct ieee80211_local *local = sdata->local;
511         struct mesh_table *tbl;
512         struct mesh_path *mpath, *new_mpath;
513         struct mpath_node *node, *new_node;
514         struct hlist_head *bucket;
515         struct hlist_node *n;
516         int grow = 0;
517         int err = 0;
518         u32 hash_idx;
519
520         if (compare_ether_addr(dst, sdata->vif.addr) == 0)
521                 /* never add ourselves as neighbours */
522                 return -ENOTSUPP;
523
524         if (is_multicast_ether_addr(dst))
525                 return -ENOTSUPP;
526
527         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
528                 return -ENOSPC;
529
530         err = -ENOMEM;
531         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
532         if (!new_mpath)
533                 goto err_path_alloc;
534
535         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
536         if (!new_node)
537                 goto err_node_alloc;
538
539         read_lock_bh(&pathtbl_resize_lock);
540         memcpy(new_mpath->dst, dst, ETH_ALEN);
541         new_mpath->sdata = sdata;
542         new_mpath->flags = 0;
543         skb_queue_head_init(&new_mpath->frame_queue);
544         new_node->mpath = new_mpath;
545         new_mpath->timer.data = (unsigned long) new_mpath;
546         new_mpath->timer.function = mesh_path_timer;
547         new_mpath->exp_time = jiffies;
548         spin_lock_init(&new_mpath->state_lock);
549         init_timer(&new_mpath->timer);
550
551         tbl = resize_dereference_mesh_paths();
552
553         hash_idx = mesh_table_hash(dst, sdata, tbl);
554         bucket = &tbl->hash_buckets[hash_idx];
555
556         spin_lock(&tbl->hashwlock[hash_idx]);
557
558         err = -EEXIST;
559         hlist_for_each_entry(node, n, bucket, list) {
560                 mpath = node->mpath;
561                 if (mpath->sdata == sdata &&
562                     compare_ether_addr(dst, mpath->dst) == 0)
563                         goto err_exists;
564         }
565
566         hlist_add_head_rcu(&new_node->list, bucket);
567         if (atomic_inc_return(&tbl->entries) >=
568             tbl->mean_chain_len * (tbl->hash_mask + 1))
569                 grow = 1;
570
571         mesh_paths_generation++;
572
573         spin_unlock(&tbl->hashwlock[hash_idx]);
574         read_unlock_bh(&pathtbl_resize_lock);
575         if (grow) {
576                 set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
577                 ieee80211_queue_work(&local->hw, &sdata->work);
578         }
579         return 0;
580
581 err_exists:
582         spin_unlock(&tbl->hashwlock[hash_idx]);
583         read_unlock_bh(&pathtbl_resize_lock);
584         kfree(new_node);
585 err_node_alloc:
586         kfree(new_mpath);
587 err_path_alloc:
588         atomic_dec(&sdata->u.mesh.mpaths);
589         return err;
590 }
591
592 static void mesh_table_free_rcu(struct rcu_head *rcu)
593 {
594         struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
595
596         mesh_table_free(tbl, false);
597 }
598
599 void mesh_mpath_table_grow(void)
600 {
601         struct mesh_table *oldtbl, *newtbl;
602
603         write_lock_bh(&pathtbl_resize_lock);
604         oldtbl = resize_dereference_mesh_paths();
605         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
606         if (!newtbl)
607                 goto out;
608         if (mesh_table_grow(oldtbl, newtbl) < 0) {
609                 __mesh_table_free(newtbl);
610                 goto out;
611         }
612         rcu_assign_pointer(mesh_paths, newtbl);
613
614         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
615
616  out:
617         write_unlock_bh(&pathtbl_resize_lock);
618 }
619
620 void mesh_mpp_table_grow(void)
621 {
622         struct mesh_table *oldtbl, *newtbl;
623
624         write_lock_bh(&pathtbl_resize_lock);
625         oldtbl = resize_dereference_mpp_paths();
626         newtbl = mesh_table_alloc(oldtbl->size_order + 1);
627         if (!newtbl)
628                 goto out;
629         if (mesh_table_grow(oldtbl, newtbl) < 0) {
630                 __mesh_table_free(newtbl);
631                 goto out;
632         }
633         rcu_assign_pointer(mpp_paths, newtbl);
634         call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
635
636  out:
637         write_unlock_bh(&pathtbl_resize_lock);
638 }
639
640 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
641 {
642         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
643         struct ieee80211_local *local = sdata->local;
644         struct mesh_table *tbl;
645         struct mesh_path *mpath, *new_mpath;
646         struct mpath_node *node, *new_node;
647         struct hlist_head *bucket;
648         struct hlist_node *n;
649         int grow = 0;
650         int err = 0;
651         u32 hash_idx;
652
653         if (compare_ether_addr(dst, sdata->vif.addr) == 0)
654                 /* never add ourselves as neighbours */
655                 return -ENOTSUPP;
656
657         if (is_multicast_ether_addr(dst))
658                 return -ENOTSUPP;
659
660         err = -ENOMEM;
661         new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
662         if (!new_mpath)
663                 goto err_path_alloc;
664
665         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
666         if (!new_node)
667                 goto err_node_alloc;
668
669         read_lock_bh(&pathtbl_resize_lock);
670         memcpy(new_mpath->dst, dst, ETH_ALEN);
671         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
672         new_mpath->sdata = sdata;
673         new_mpath->flags = 0;
674         skb_queue_head_init(&new_mpath->frame_queue);
675         new_node->mpath = new_mpath;
676         init_timer(&new_mpath->timer);
677         new_mpath->exp_time = jiffies;
678         spin_lock_init(&new_mpath->state_lock);
679
680         tbl = resize_dereference_mpp_paths();
681
682         hash_idx = mesh_table_hash(dst, sdata, tbl);
683         bucket = &tbl->hash_buckets[hash_idx];
684
685         spin_lock(&tbl->hashwlock[hash_idx]);
686
687         err = -EEXIST;
688         hlist_for_each_entry(node, n, bucket, list) {
689                 mpath = node->mpath;
690                 if (mpath->sdata == sdata &&
691                     compare_ether_addr(dst, mpath->dst) == 0)
692                         goto err_exists;
693         }
694
695         hlist_add_head_rcu(&new_node->list, bucket);
696         if (atomic_inc_return(&tbl->entries) >=
697             tbl->mean_chain_len * (tbl->hash_mask + 1))
698                 grow = 1;
699
700         spin_unlock(&tbl->hashwlock[hash_idx]);
701         read_unlock_bh(&pathtbl_resize_lock);
702         if (grow) {
703                 set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
704                 ieee80211_queue_work(&local->hw, &sdata->work);
705         }
706         return 0;
707
708 err_exists:
709         spin_unlock(&tbl->hashwlock[hash_idx]);
710         read_unlock_bh(&pathtbl_resize_lock);
711         kfree(new_node);
712 err_node_alloc:
713         kfree(new_mpath);
714 err_path_alloc:
715         return err;
716 }
717
718
719 /**
720  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
721  *
722  * @sta: broken peer link
723  *
724  * This function must be called from the rate control algorithm if enough
725  * delivery errors suggest that a peer link is no longer usable.
726  */
727 void mesh_plink_broken(struct sta_info *sta)
728 {
729         struct mesh_table *tbl;
730         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
731         struct mesh_path *mpath;
732         struct mpath_node *node;
733         struct hlist_node *p;
734         struct ieee80211_sub_if_data *sdata = sta->sdata;
735         int i;
736         __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_DEST_UNREACHABLE);
737
738         rcu_read_lock();
739         tbl = rcu_dereference(mesh_paths);
740         for_each_mesh_entry(tbl, p, node, i) {
741                 mpath = node->mpath;
742                 if (rcu_dereference(mpath->next_hop) == sta &&
743                     mpath->flags & MESH_PATH_ACTIVE &&
744                     !(mpath->flags & MESH_PATH_FIXED)) {
745                         spin_lock_bh(&mpath->state_lock);
746                         mpath->flags &= ~MESH_PATH_ACTIVE;
747                         ++mpath->sn;
748                         spin_unlock_bh(&mpath->state_lock);
749                         mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
750                                         mpath->dst, cpu_to_le32(mpath->sn),
751                                         reason, bcast, sdata);
752                 }
753         }
754         rcu_read_unlock();
755 }
756
757 static void mesh_path_node_reclaim(struct rcu_head *rp)
758 {
759         struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
760         struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
761
762         del_timer_sync(&node->mpath->timer);
763         atomic_dec(&sdata->u.mesh.mpaths);
764         kfree(node->mpath);
765         kfree(node);
766 }
767
768 /* needs to be called with the corresponding hashwlock taken */
769 static void __mesh_path_del(struct mesh_table *tbl, struct mpath_node *node)
770 {
771         struct mesh_path *mpath;
772         mpath = node->mpath;
773         spin_lock(&mpath->state_lock);
774         mpath->flags |= MESH_PATH_RESOLVING;
775         if (mpath->is_gate)
776                 mesh_gate_del(tbl, mpath);
777         hlist_del_rcu(&node->list);
778         call_rcu(&node->rcu, mesh_path_node_reclaim);
779         spin_unlock(&mpath->state_lock);
780         atomic_dec(&tbl->entries);
781 }
782
783 /**
784  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
785  *
786  * @sta - mesh peer to match
787  *
788  * RCU notes: this function is called when a mesh plink transitions from
789  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
790  * allows path creation. This will happen before the sta can be freed (because
791  * sta_info_destroy() calls this) so any reader in a rcu read block will be
792  * protected against the plink disappearing.
793  */
794 void mesh_path_flush_by_nexthop(struct sta_info *sta)
795 {
796         struct mesh_table *tbl;
797         struct mesh_path *mpath;
798         struct mpath_node *node;
799         struct hlist_node *p;
800         int i;
801
802         rcu_read_lock();
803         read_lock_bh(&pathtbl_resize_lock);
804         tbl = resize_dereference_mesh_paths();
805         for_each_mesh_entry(tbl, p, node, i) {
806                 mpath = node->mpath;
807                 if (rcu_dereference(mpath->next_hop) == sta) {
808                         spin_lock(&tbl->hashwlock[i]);
809                         __mesh_path_del(tbl, node);
810                         spin_unlock(&tbl->hashwlock[i]);
811                 }
812         }
813         read_unlock_bh(&pathtbl_resize_lock);
814         rcu_read_unlock();
815 }
816
817 static void table_flush_by_iface(struct mesh_table *tbl,
818                                  struct ieee80211_sub_if_data *sdata)
819 {
820         struct mesh_path *mpath;
821         struct mpath_node *node;
822         struct hlist_node *p;
823         int i;
824
825         WARN_ON(!rcu_read_lock_held());
826         for_each_mesh_entry(tbl, p, node, i) {
827                 mpath = node->mpath;
828                 if (mpath->sdata != sdata)
829                         continue;
830                 spin_lock_bh(&tbl->hashwlock[i]);
831                 __mesh_path_del(tbl, node);
832                 spin_unlock_bh(&tbl->hashwlock[i]);
833         }
834 }
835
836 /**
837  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
838  *
839  * This function deletes both mesh paths as well as mesh portal paths.
840  *
841  * @sdata - interface data to match
842  *
843  */
844 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
845 {
846         struct mesh_table *tbl;
847
848         rcu_read_lock();
849         read_lock_bh(&pathtbl_resize_lock);
850         tbl = resize_dereference_mesh_paths();
851         table_flush_by_iface(tbl, sdata);
852         tbl = resize_dereference_mpp_paths();
853         table_flush_by_iface(tbl, sdata);
854         read_unlock_bh(&pathtbl_resize_lock);
855         rcu_read_unlock();
856 }
857
858 /**
859  * mesh_path_del - delete a mesh path from the table
860  *
861  * @addr: dst address (ETH_ALEN length)
862  * @sdata: local subif
863  *
864  * Returns: 0 if successful
865  */
866 int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
867 {
868         struct mesh_table *tbl;
869         struct mesh_path *mpath;
870         struct mpath_node *node;
871         struct hlist_head *bucket;
872         struct hlist_node *n;
873         int hash_idx;
874         int err = 0;
875
876         read_lock_bh(&pathtbl_resize_lock);
877         tbl = resize_dereference_mesh_paths();
878         hash_idx = mesh_table_hash(addr, sdata, tbl);
879         bucket = &tbl->hash_buckets[hash_idx];
880
881         spin_lock(&tbl->hashwlock[hash_idx]);
882         hlist_for_each_entry(node, n, bucket, list) {
883                 mpath = node->mpath;
884                 if (mpath->sdata == sdata &&
885                     compare_ether_addr(addr, mpath->dst) == 0) {
886                         __mesh_path_del(tbl, node);
887                         goto enddel;
888                 }
889         }
890
891         err = -ENXIO;
892 enddel:
893         mesh_paths_generation++;
894         spin_unlock(&tbl->hashwlock[hash_idx]);
895         read_unlock_bh(&pathtbl_resize_lock);
896         return err;
897 }
898
899 /**
900  * mesh_path_tx_pending - sends pending frames in a mesh path queue
901  *
902  * @mpath: mesh path to activate
903  *
904  * Locking: the state_lock of the mpath structure must NOT be held when calling
905  * this function.
906  */
907 void mesh_path_tx_pending(struct mesh_path *mpath)
908 {
909         if (mpath->flags & MESH_PATH_ACTIVE)
910                 ieee80211_add_pending_skbs(mpath->sdata->local,
911                                 &mpath->frame_queue);
912 }
913
914 /**
915  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
916  *
917  * @mpath: mesh path whose queue will be emptied
918  *
919  * If there is only one gate, the frames are transferred from the failed mpath
920  * queue to that gate's queue.  If there are more than one gates, the frames
921  * are copied from each gate to the next.  After frames are copied, the
922  * mpath queues are emptied onto the transmission queue.
923  */
924 int mesh_path_send_to_gates(struct mesh_path *mpath)
925 {
926         struct ieee80211_sub_if_data *sdata = mpath->sdata;
927         struct hlist_node *n;
928         struct mesh_table *tbl;
929         struct mesh_path *from_mpath = mpath;
930         struct mpath_node *gate = NULL;
931         bool copy = false;
932         struct hlist_head *known_gates;
933
934         rcu_read_lock();
935         tbl = rcu_dereference(mesh_paths);
936         known_gates = tbl->known_gates;
937         rcu_read_unlock();
938
939         if (!known_gates)
940                 return -EHOSTUNREACH;
941
942         hlist_for_each_entry_rcu(gate, n, known_gates, list) {
943                 if (gate->mpath->sdata != sdata)
944                         continue;
945
946                 if (gate->mpath->flags & MESH_PATH_ACTIVE) {
947                         mpath_dbg("Forwarding to %pM\n", gate->mpath->dst);
948                         mesh_path_move_to_queue(gate->mpath, from_mpath, copy);
949                         from_mpath = gate->mpath;
950                         copy = true;
951                 } else {
952                         mpath_dbg("Not forwarding %p\n", gate->mpath);
953                         mpath_dbg("flags %x\n", gate->mpath->flags);
954                 }
955         }
956
957         hlist_for_each_entry_rcu(gate, n, known_gates, list)
958                 if (gate->mpath->sdata == sdata) {
959                         mpath_dbg("Sending to %pM\n", gate->mpath->dst);
960                         mesh_path_tx_pending(gate->mpath);
961                 }
962
963         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
964 }
965
966 /**
967  * mesh_path_discard_frame - discard a frame whose path could not be resolved
968  *
969  * @skb: frame to discard
970  * @sdata: network subif the frame was to be sent through
971  *
972  * Locking: the function must me called within a rcu_read_lock region
973  */
974 void mesh_path_discard_frame(struct sk_buff *skb,
975                              struct ieee80211_sub_if_data *sdata)
976 {
977         kfree_skb(skb);
978         sdata->u.mesh.mshstats.dropped_frames_no_route++;
979 }
980
981 /**
982  * mesh_path_flush_pending - free the pending queue of a mesh path
983  *
984  * @mpath: mesh path whose queue has to be freed
985  *
986  * Locking: the function must me called within a rcu_read_lock region
987  */
988 void mesh_path_flush_pending(struct mesh_path *mpath)
989 {
990         struct sk_buff *skb;
991
992         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
993                 mesh_path_discard_frame(skb, mpath->sdata);
994 }
995
996 /**
997  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
998  *
999  * @mpath: the mesh path to modify
1000  * @next_hop: the next hop to force
1001  *
1002  * Locking: this function must be called holding mpath->state_lock
1003  */
1004 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
1005 {
1006         spin_lock_bh(&mpath->state_lock);
1007         mesh_path_assign_nexthop(mpath, next_hop);
1008         mpath->sn = 0xffff;
1009         mpath->metric = 0;
1010         mpath->hop_count = 0;
1011         mpath->exp_time = 0;
1012         mpath->flags |= MESH_PATH_FIXED;
1013         mesh_path_activate(mpath);
1014         spin_unlock_bh(&mpath->state_lock);
1015         mesh_path_tx_pending(mpath);
1016 }
1017
1018 static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
1019 {
1020         struct mesh_path *mpath;
1021         struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
1022         mpath = node->mpath;
1023         hlist_del_rcu(p);
1024         if (free_leafs) {
1025                 del_timer_sync(&mpath->timer);
1026                 kfree(mpath);
1027         }
1028         kfree(node);
1029 }
1030
1031 static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
1032 {
1033         struct mesh_path *mpath;
1034         struct mpath_node *node, *new_node;
1035         u32 hash_idx;
1036
1037         new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
1038         if (new_node == NULL)
1039                 return -ENOMEM;
1040
1041         node = hlist_entry(p, struct mpath_node, list);
1042         mpath = node->mpath;
1043         new_node->mpath = mpath;
1044         hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
1045         hlist_add_head(&new_node->list,
1046                         &newtbl->hash_buckets[hash_idx]);
1047         return 0;
1048 }
1049
1050 int mesh_pathtbl_init(void)
1051 {
1052         struct mesh_table *tbl_path, *tbl_mpp;
1053         int ret;
1054
1055         tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1056         if (!tbl_path)
1057                 return -ENOMEM;
1058         tbl_path->free_node = &mesh_path_node_free;
1059         tbl_path->copy_node = &mesh_path_node_copy;
1060         tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
1061         tbl_path->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1062         if (!tbl_path->known_gates) {
1063                 ret = -ENOMEM;
1064                 goto free_path;
1065         }
1066         INIT_HLIST_HEAD(tbl_path->known_gates);
1067
1068
1069         tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
1070         if (!tbl_mpp) {
1071                 ret = -ENOMEM;
1072                 goto free_path;
1073         }
1074         tbl_mpp->free_node = &mesh_path_node_free;
1075         tbl_mpp->copy_node = &mesh_path_node_copy;
1076         tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
1077         tbl_mpp->known_gates = kzalloc(sizeof(struct hlist_head), GFP_ATOMIC);
1078         if (!tbl_mpp->known_gates) {
1079                 ret = -ENOMEM;
1080                 goto free_mpp;
1081         }
1082         INIT_HLIST_HEAD(tbl_mpp->known_gates);
1083
1084         /* Need no locking since this is during init */
1085         RCU_INIT_POINTER(mesh_paths, tbl_path);
1086         RCU_INIT_POINTER(mpp_paths, tbl_mpp);
1087
1088         return 0;
1089
1090 free_mpp:
1091         mesh_table_free(tbl_mpp, true);
1092 free_path:
1093         mesh_table_free(tbl_path, true);
1094         return ret;
1095 }
1096
1097 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
1098 {
1099         struct mesh_table *tbl;
1100         struct mesh_path *mpath;
1101         struct mpath_node *node;
1102         struct hlist_node *p;
1103         int i;
1104
1105         rcu_read_lock();
1106         tbl = rcu_dereference(mesh_paths);
1107         for_each_mesh_entry(tbl, p, node, i) {
1108                 if (node->mpath->sdata != sdata)
1109                         continue;
1110                 mpath = node->mpath;
1111                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
1112                     (!(mpath->flags & MESH_PATH_FIXED)) &&
1113                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
1114                         mesh_path_del(mpath->dst, mpath->sdata);
1115         }
1116         rcu_read_unlock();
1117 }
1118
1119 void mesh_pathtbl_unregister(void)
1120 {
1121         /* no need for locking during exit path */
1122         mesh_table_free(rcu_dereference_protected(mesh_paths, 1), true);
1123         mesh_table_free(rcu_dereference_protected(mpp_paths, 1), true);
1124 }