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eb2b9311 LCC |
1 | /* |
2 | * Copyright (c) 2008 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/netdevice.h> | |
13 | #include <linux/random.h> | |
14 | #include <linux/spinlock.h> | |
15 | #include <linux/string.h> | |
16 | #include <net/mac80211.h> | |
17 | #include "ieee80211_i.h" | |
18 | #include "mesh.h" | |
19 | ||
20 | /* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */ | |
21 | #define INIT_PATHS_SIZE_ORDER 2 | |
22 | ||
23 | /* Keep the mean chain length below this constant */ | |
24 | #define MEAN_CHAIN_LEN 2 | |
25 | ||
26 | #define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \ | |
27 | time_after(jiffies, mpath->exp_time) && \ | |
28 | !(mpath->flags & MESH_PATH_FIXED)) | |
29 | ||
30 | struct mpath_node { | |
31 | struct hlist_node list; | |
32 | struct rcu_head rcu; | |
33 | /* This indirection allows two different tables to point to the same | |
34 | * mesh_path structure, useful when resizing | |
35 | */ | |
36 | struct mesh_path *mpath; | |
37 | }; | |
38 | ||
39 | static struct mesh_table *mesh_paths; | |
40 | ||
41 | /* This lock will have the grow table function as writer and add / delete nodes | |
42 | * as readers. When reading the table (i.e. doing lookups) we are well protected | |
43 | * by RCU | |
44 | */ | |
45 | static DEFINE_RWLOCK(pathtbl_resize_lock); | |
46 | ||
47 | /** | |
48 | * | |
49 | * mesh_path_assign_nexthop - update mesh path next hop | |
50 | * | |
51 | * @mpath: mesh path to update | |
52 | * @sta: next hop to assign | |
53 | * | |
54 | * Locking: mpath->state_lock must be held when calling this function | |
55 | */ | |
56 | void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta) | |
57 | { | |
d0709a65 | 58 | rcu_assign_pointer(mpath->next_hop, sta); |
eb2b9311 LCC |
59 | } |
60 | ||
61 | ||
62 | /** | |
63 | * mesh_path_lookup - look up a path in the mesh path table | |
64 | * @dst: hardware address (ETH_ALEN length) of destination | |
65 | * @dev: local interface | |
66 | * | |
67 | * Returns: pointer to the mesh path structure, or NULL if not found | |
68 | * | |
69 | * Locking: must be called within a read rcu section. | |
70 | */ | |
71 | struct mesh_path *mesh_path_lookup(u8 *dst, struct net_device *dev) | |
72 | { | |
73 | struct mesh_path *mpath; | |
74 | struct hlist_node *n; | |
75 | struct hlist_head *bucket; | |
76 | struct mesh_table *tbl; | |
77 | struct mpath_node *node; | |
78 | ||
79 | tbl = rcu_dereference(mesh_paths); | |
80 | ||
81 | bucket = &tbl->hash_buckets[mesh_table_hash(dst, dev, tbl)]; | |
82 | hlist_for_each_entry_rcu(node, n, bucket, list) { | |
83 | mpath = node->mpath; | |
84 | if (mpath->dev == dev && | |
85 | memcmp(dst, mpath->dst, ETH_ALEN) == 0) { | |
86 | if (MPATH_EXPIRED(mpath)) { | |
87 | spin_lock_bh(&mpath->state_lock); | |
88 | if (MPATH_EXPIRED(mpath)) | |
89 | mpath->flags &= ~MESH_PATH_ACTIVE; | |
90 | spin_unlock_bh(&mpath->state_lock); | |
91 | } | |
92 | return mpath; | |
93 | } | |
94 | } | |
95 | return NULL; | |
96 | } | |
97 | ||
98 | /** | |
99 | * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index | |
100 | * @idx: index | |
2a8ca29a | 101 | * @dev: local interface, or NULL for all entries |
eb2b9311 LCC |
102 | * |
103 | * Returns: pointer to the mesh path structure, or NULL if not found. | |
104 | * | |
105 | * Locking: must be called within a read rcu section. | |
106 | */ | |
107 | struct mesh_path *mesh_path_lookup_by_idx(int idx, struct net_device *dev) | |
108 | { | |
109 | struct mpath_node *node; | |
110 | struct hlist_node *p; | |
111 | int i; | |
112 | int j = 0; | |
113 | ||
2a8ca29a LCC |
114 | for_each_mesh_entry(mesh_paths, p, node, i) { |
115 | if (dev && node->mpath->dev != dev) | |
116 | continue; | |
eb2b9311 LCC |
117 | if (j++ == idx) { |
118 | if (MPATH_EXPIRED(node->mpath)) { | |
119 | spin_lock_bh(&node->mpath->state_lock); | |
120 | if (MPATH_EXPIRED(node->mpath)) | |
121 | node->mpath->flags &= ~MESH_PATH_ACTIVE; | |
122 | spin_unlock_bh(&node->mpath->state_lock); | |
123 | } | |
124 | return node->mpath; | |
125 | } | |
2a8ca29a | 126 | } |
eb2b9311 LCC |
127 | |
128 | return NULL; | |
129 | } | |
130 | ||
131 | /** | |
132 | * mesh_path_add - allocate and add a new path to the mesh path table | |
133 | * @addr: destination address of the path (ETH_ALEN length) | |
134 | * @dev: local interface | |
135 | * | |
136 | * Returns: 0 on sucess | |
137 | * | |
138 | * State: the initial state of the new path is set to 0 | |
139 | */ | |
140 | int mesh_path_add(u8 *dst, struct net_device *dev) | |
141 | { | |
142 | struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); | |
143 | struct mesh_path *mpath, *new_mpath; | |
144 | struct mpath_node *node, *new_node; | |
145 | struct hlist_head *bucket; | |
146 | struct hlist_node *n; | |
147 | int grow = 0; | |
148 | int err = 0; | |
149 | u32 hash_idx; | |
150 | ||
151 | if (memcmp(dst, dev->dev_addr, ETH_ALEN) == 0) | |
152 | /* never add ourselves as neighbours */ | |
153 | return -ENOTSUPP; | |
154 | ||
155 | if (is_multicast_ether_addr(dst)) | |
156 | return -ENOTSUPP; | |
157 | ||
158 | if (atomic_add_unless(&sdata->u.sta.mpaths, 1, MESH_MAX_MPATHS) == 0) | |
159 | return -ENOSPC; | |
160 | ||
161 | read_lock(&pathtbl_resize_lock); | |
162 | ||
163 | new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL); | |
164 | if (!new_mpath) { | |
165 | atomic_dec(&sdata->u.sta.mpaths); | |
166 | err = -ENOMEM; | |
167 | goto endadd2; | |
168 | } | |
169 | memcpy(new_mpath->dst, dst, ETH_ALEN); | |
170 | new_mpath->dev = dev; | |
171 | new_mpath->flags = 0; | |
172 | skb_queue_head_init(&new_mpath->frame_queue); | |
173 | new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL); | |
174 | new_node->mpath = new_mpath; | |
175 | new_mpath->timer.data = (unsigned long) new_mpath; | |
176 | new_mpath->timer.function = mesh_path_timer; | |
177 | new_mpath->exp_time = jiffies; | |
178 | spin_lock_init(&new_mpath->state_lock); | |
179 | init_timer(&new_mpath->timer); | |
180 | ||
181 | hash_idx = mesh_table_hash(dst, dev, mesh_paths); | |
182 | bucket = &mesh_paths->hash_buckets[hash_idx]; | |
183 | ||
184 | spin_lock(&mesh_paths->hashwlock[hash_idx]); | |
185 | ||
186 | hlist_for_each_entry(node, n, bucket, list) { | |
187 | mpath = node->mpath; | |
188 | if (mpath->dev == dev && memcmp(dst, mpath->dst, ETH_ALEN) | |
189 | == 0) { | |
190 | err = -EEXIST; | |
191 | atomic_dec(&sdata->u.sta.mpaths); | |
192 | kfree(new_node); | |
193 | kfree(new_mpath); | |
194 | goto endadd; | |
195 | } | |
196 | } | |
197 | ||
198 | hlist_add_head_rcu(&new_node->list, bucket); | |
199 | if (atomic_inc_return(&mesh_paths->entries) >= | |
200 | mesh_paths->mean_chain_len * (mesh_paths->hash_mask + 1)) | |
201 | grow = 1; | |
202 | ||
203 | endadd: | |
204 | spin_unlock(&mesh_paths->hashwlock[hash_idx]); | |
205 | endadd2: | |
206 | read_unlock(&pathtbl_resize_lock); | |
207 | if (!err && grow) { | |
208 | struct mesh_table *oldtbl, *newtbl; | |
209 | ||
210 | write_lock(&pathtbl_resize_lock); | |
211 | oldtbl = mesh_paths; | |
212 | newtbl = mesh_table_grow(mesh_paths); | |
213 | if (!newtbl) { | |
214 | write_unlock(&pathtbl_resize_lock); | |
215 | return -ENOMEM; | |
216 | } | |
217 | rcu_assign_pointer(mesh_paths, newtbl); | |
218 | synchronize_rcu(); | |
219 | mesh_table_free(oldtbl, false); | |
220 | write_unlock(&pathtbl_resize_lock); | |
221 | } | |
222 | return err; | |
223 | } | |
224 | ||
225 | ||
226 | /** | |
227 | * mesh_plink_broken - deactivates paths and sends perr when a link breaks | |
228 | * | |
229 | * @sta: broken peer link | |
230 | * | |
231 | * This function must be called from the rate control algorithm if enough | |
232 | * delivery errors suggest that a peer link is no longer usable. | |
233 | */ | |
234 | void mesh_plink_broken(struct sta_info *sta) | |
235 | { | |
236 | struct mesh_path *mpath; | |
237 | struct mpath_node *node; | |
238 | struct hlist_node *p; | |
d0709a65 | 239 | struct net_device *dev = sta->sdata->dev; |
eb2b9311 LCC |
240 | int i; |
241 | ||
242 | rcu_read_lock(); | |
243 | for_each_mesh_entry(mesh_paths, p, node, i) { | |
244 | mpath = node->mpath; | |
245 | spin_lock_bh(&mpath->state_lock); | |
246 | if (mpath->next_hop == sta && | |
247 | mpath->flags & MESH_PATH_ACTIVE && | |
248 | !(mpath->flags & MESH_PATH_FIXED)) { | |
249 | mpath->flags &= ~MESH_PATH_ACTIVE; | |
250 | ++mpath->dsn; | |
251 | spin_unlock_bh(&mpath->state_lock); | |
252 | mesh_path_error_tx(mpath->dst, | |
253 | cpu_to_le32(mpath->dsn), | |
254 | dev->broadcast, dev); | |
255 | } else | |
256 | spin_unlock_bh(&mpath->state_lock); | |
257 | } | |
258 | rcu_read_unlock(); | |
259 | } | |
c1edd987 | 260 | EXPORT_SYMBOL(mesh_plink_broken); |
eb2b9311 LCC |
261 | |
262 | /** | |
263 | * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches | |
264 | * | |
265 | * @sta - mesh peer to match | |
266 | * | |
b4e08ea1 LCC |
267 | * RCU notes: this function is called when a mesh plink transitions from |
268 | * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that | |
269 | * allows path creation. This will happen before the sta can be freed (because | |
d0709a65 JB |
270 | * sta_info_destroy() calls this) so any reader in a rcu read block will be |
271 | * protected against the plink disappearing. | |
eb2b9311 LCC |
272 | */ |
273 | void mesh_path_flush_by_nexthop(struct sta_info *sta) | |
274 | { | |
275 | struct mesh_path *mpath; | |
276 | struct mpath_node *node; | |
277 | struct hlist_node *p; | |
278 | int i; | |
279 | ||
280 | for_each_mesh_entry(mesh_paths, p, node, i) { | |
281 | mpath = node->mpath; | |
282 | if (mpath->next_hop == sta) | |
cfa22c71 | 283 | mesh_path_del(mpath->dst, mpath->dev); |
eb2b9311 LCC |
284 | } |
285 | } | |
286 | ||
287 | void mesh_path_flush(struct net_device *dev) | |
288 | { | |
289 | struct mesh_path *mpath; | |
290 | struct mpath_node *node; | |
291 | struct hlist_node *p; | |
292 | int i; | |
293 | ||
294 | for_each_mesh_entry(mesh_paths, p, node, i) { | |
295 | mpath = node->mpath; | |
296 | if (mpath->dev == dev) | |
cfa22c71 | 297 | mesh_path_del(mpath->dst, mpath->dev); |
eb2b9311 LCC |
298 | } |
299 | } | |
300 | ||
301 | static void mesh_path_node_reclaim(struct rcu_head *rp) | |
302 | { | |
303 | struct mpath_node *node = container_of(rp, struct mpath_node, rcu); | |
304 | struct ieee80211_sub_if_data *sdata = | |
305 | IEEE80211_DEV_TO_SUB_IF(node->mpath->dev); | |
d0709a65 | 306 | |
89a1ad69 | 307 | del_timer_sync(&node->mpath->timer); |
eb2b9311 LCC |
308 | atomic_dec(&sdata->u.sta.mpaths); |
309 | kfree(node->mpath); | |
310 | kfree(node); | |
311 | } | |
312 | ||
313 | /** | |
314 | * mesh_path_del - delete a mesh path from the table | |
315 | * | |
316 | * @addr: dst address (ETH_ALEN length) | |
317 | * @dev: local interface | |
318 | * | |
319 | * Returns: 0 if succesful | |
eb2b9311 | 320 | */ |
cfa22c71 | 321 | int mesh_path_del(u8 *addr, struct net_device *dev) |
eb2b9311 LCC |
322 | { |
323 | struct mesh_path *mpath; | |
324 | struct mpath_node *node; | |
325 | struct hlist_head *bucket; | |
326 | struct hlist_node *n; | |
327 | int hash_idx; | |
328 | int err = 0; | |
329 | ||
330 | read_lock(&pathtbl_resize_lock); | |
331 | hash_idx = mesh_table_hash(addr, dev, mesh_paths); | |
332 | bucket = &mesh_paths->hash_buckets[hash_idx]; | |
333 | ||
334 | spin_lock(&mesh_paths->hashwlock[hash_idx]); | |
335 | hlist_for_each_entry(node, n, bucket, list) { | |
336 | mpath = node->mpath; | |
337 | if (mpath->dev == dev && | |
338 | memcmp(addr, mpath->dst, ETH_ALEN) == 0) { | |
339 | spin_lock_bh(&mpath->state_lock); | |
cfa22c71 LCC |
340 | mpath->flags |= MESH_PATH_RESOLVING; |
341 | hlist_del_rcu(&node->list); | |
342 | call_rcu(&node->rcu, mesh_path_node_reclaim); | |
343 | atomic_dec(&mesh_paths->entries); | |
eb2b9311 LCC |
344 | spin_unlock_bh(&mpath->state_lock); |
345 | goto enddel; | |
346 | } | |
347 | } | |
348 | ||
349 | err = -ENXIO; | |
350 | enddel: | |
351 | spin_unlock(&mesh_paths->hashwlock[hash_idx]); | |
352 | read_unlock(&pathtbl_resize_lock); | |
353 | return err; | |
354 | } | |
355 | ||
356 | /** | |
357 | * mesh_path_tx_pending - sends pending frames in a mesh path queue | |
358 | * | |
359 | * @mpath: mesh path to activate | |
360 | * | |
361 | * Locking: the state_lock of the mpath structure must NOT be held when calling | |
362 | * this function. | |
363 | */ | |
364 | void mesh_path_tx_pending(struct mesh_path *mpath) | |
365 | { | |
366 | struct sk_buff *skb; | |
367 | ||
368 | while ((skb = skb_dequeue(&mpath->frame_queue)) && | |
369 | (mpath->flags & MESH_PATH_ACTIVE)) | |
370 | dev_queue_xmit(skb); | |
371 | } | |
372 | ||
373 | /** | |
374 | * mesh_path_discard_frame - discard a frame whose path could not be resolved | |
375 | * | |
376 | * @skb: frame to discard | |
377 | * @dev: network device the frame was to be sent through | |
378 | * | |
379 | * If the frame was beign forwarded from another MP, a PERR frame will be sent | |
380 | * to the precursor. | |
381 | * | |
382 | * Locking: the function must me called within a rcu_read_lock region | |
383 | */ | |
384 | void mesh_path_discard_frame(struct sk_buff *skb, struct net_device *dev) | |
385 | { | |
386 | struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); | |
387 | struct mesh_path *mpath; | |
388 | u32 dsn = 0; | |
389 | ||
390 | if (skb->pkt_type == PACKET_OTHERHOST) { | |
391 | struct ieee80211s_hdr *prev_meshhdr; | |
392 | int mshhdrlen; | |
393 | u8 *ra, *da; | |
394 | ||
395 | prev_meshhdr = ((struct ieee80211s_hdr *)skb->cb); | |
396 | mshhdrlen = ieee80211_get_mesh_hdrlen(prev_meshhdr); | |
397 | da = skb->data; | |
398 | ra = MESH_PREQ(skb); | |
399 | mpath = mesh_path_lookup(da, dev); | |
400 | if (mpath) | |
401 | dsn = ++mpath->dsn; | |
402 | mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, dev); | |
403 | } | |
404 | ||
405 | kfree_skb(skb); | |
406 | sdata->u.sta.mshstats.dropped_frames_no_route++; | |
407 | } | |
408 | ||
409 | /** | |
410 | * mesh_path_flush_pending - free the pending queue of a mesh path | |
411 | * | |
412 | * @mpath: mesh path whose queue has to be freed | |
413 | * | |
414 | * Locking: the function must me called withing a rcu_read_lock region | |
415 | */ | |
416 | void mesh_path_flush_pending(struct mesh_path *mpath) | |
417 | { | |
418 | struct ieee80211_sub_if_data *sdata; | |
419 | struct sk_buff *skb; | |
420 | ||
421 | sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev); | |
422 | ||
423 | while ((skb = skb_dequeue(&mpath->frame_queue)) && | |
424 | (mpath->flags & MESH_PATH_ACTIVE)) | |
425 | mesh_path_discard_frame(skb, mpath->dev); | |
426 | } | |
427 | ||
428 | /** | |
429 | * mesh_path_fix_nexthop - force a specific next hop for a mesh path | |
430 | * | |
431 | * @mpath: the mesh path to modify | |
432 | * @next_hop: the next hop to force | |
433 | * | |
434 | * Locking: this function must be called holding mpath->state_lock | |
435 | */ | |
436 | void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop) | |
437 | { | |
438 | spin_lock_bh(&mpath->state_lock); | |
439 | mesh_path_assign_nexthop(mpath, next_hop); | |
440 | mpath->dsn = 0xffff; | |
441 | mpath->metric = 0; | |
442 | mpath->hop_count = 0; | |
443 | mpath->exp_time = 0; | |
444 | mpath->flags |= MESH_PATH_FIXED; | |
445 | mesh_path_activate(mpath); | |
446 | spin_unlock_bh(&mpath->state_lock); | |
447 | mesh_path_tx_pending(mpath); | |
448 | } | |
449 | ||
450 | static void mesh_path_node_free(struct hlist_node *p, bool free_leafs) | |
451 | { | |
452 | struct mesh_path *mpath; | |
453 | struct mpath_node *node = hlist_entry(p, struct mpath_node, list); | |
454 | mpath = node->mpath; | |
455 | hlist_del_rcu(p); | |
456 | synchronize_rcu(); | |
457 | if (free_leafs) | |
458 | kfree(mpath); | |
459 | kfree(node); | |
460 | } | |
461 | ||
462 | static void mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl) | |
463 | { | |
464 | struct mesh_path *mpath; | |
465 | struct mpath_node *node, *new_node; | |
466 | u32 hash_idx; | |
467 | ||
468 | node = hlist_entry(p, struct mpath_node, list); | |
469 | mpath = node->mpath; | |
470 | new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL); | |
471 | new_node->mpath = mpath; | |
472 | hash_idx = mesh_table_hash(mpath->dst, mpath->dev, newtbl); | |
473 | hlist_add_head(&new_node->list, | |
474 | &newtbl->hash_buckets[hash_idx]); | |
475 | } | |
476 | ||
477 | int mesh_pathtbl_init(void) | |
478 | { | |
479 | mesh_paths = mesh_table_alloc(INIT_PATHS_SIZE_ORDER); | |
480 | mesh_paths->free_node = &mesh_path_node_free; | |
481 | mesh_paths->copy_node = &mesh_path_node_copy; | |
482 | mesh_paths->mean_chain_len = MEAN_CHAIN_LEN; | |
483 | if (!mesh_paths) | |
484 | return -ENOMEM; | |
485 | return 0; | |
486 | } | |
487 | ||
488 | void mesh_path_expire(struct net_device *dev) | |
489 | { | |
490 | struct mesh_path *mpath; | |
491 | struct mpath_node *node; | |
492 | struct hlist_node *p; | |
493 | int i; | |
494 | ||
495 | read_lock(&pathtbl_resize_lock); | |
496 | for_each_mesh_entry(mesh_paths, p, node, i) { | |
497 | if (node->mpath->dev != dev) | |
498 | continue; | |
499 | mpath = node->mpath; | |
500 | spin_lock_bh(&mpath->state_lock); | |
501 | if ((!(mpath->flags & MESH_PATH_RESOLVING)) && | |
502 | (!(mpath->flags & MESH_PATH_FIXED)) && | |
503 | time_after(jiffies, | |
504 | mpath->exp_time + MESH_PATH_EXPIRE)) { | |
505 | spin_unlock_bh(&mpath->state_lock); | |
cfa22c71 | 506 | mesh_path_del(mpath->dst, mpath->dev); |
eb2b9311 LCC |
507 | } else |
508 | spin_unlock_bh(&mpath->state_lock); | |
509 | } | |
510 | read_unlock(&pathtbl_resize_lock); | |
511 | } | |
512 | ||
513 | void mesh_pathtbl_unregister(void) | |
514 | { | |
515 | mesh_table_free(mesh_paths, true); | |
516 | } |