xref: /openbmc/linux/net/mac80211/mesh.c (revision 545e4006)
1 /*
2  * Copyright (c) 2008 open80211s Ltd.
3  * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
4  * 	       Javier Cardona <javier@cozybit.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #include <asm/unaligned.h>
12 #include "ieee80211_i.h"
13 #include "mesh.h"
14 
15 #define PP_OFFSET 	1		/* Path Selection Protocol */
16 #define PM_OFFSET	5		/* Path Selection Metric   */
17 #define CC_OFFSET	9		/* Congestion Control Mode */
18 #define CAPAB_OFFSET 17
19 #define ACCEPT_PLINKS 0x80
20 
21 int mesh_allocated;
22 static struct kmem_cache *rm_cache;
23 
24 void ieee80211s_init(void)
25 {
26 	mesh_pathtbl_init();
27 	mesh_allocated = 1;
28 	rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
29 				     0, 0, NULL);
30 }
31 
32 void ieee80211s_stop(void)
33 {
34 	mesh_pathtbl_unregister();
35 	kmem_cache_destroy(rm_cache);
36 }
37 
38 /**
39  * mesh_matches_local - check if the config of a mesh point matches ours
40  *
41  * @ie: information elements of a management frame from the mesh peer
42  * @dev: local mesh interface
43  *
44  * This function checks if the mesh configuration of a mesh point matches the
45  * local mesh configuration, i.e. if both nodes belong to the same mesh network.
46  */
47 bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev)
48 {
49 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
50 	struct ieee80211_if_sta *sta = &sdata->u.sta;
51 
52 	/*
53 	 * As support for each feature is added, check for matching
54 	 * - On mesh config capabilities
55 	 *   - Power Save Support En
56 	 *   - Sync support enabled
57 	 *   - Sync support active
58 	 *   - Sync support required from peer
59 	 *   - MDA enabled
60 	 * - Power management control on fc
61 	 */
62 	if (sta->mesh_id_len == ie->mesh_id_len &&
63 		memcmp(sta->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&
64 		memcmp(sta->mesh_pp_id, ie->mesh_config + PP_OFFSET, 4) == 0 &&
65 		memcmp(sta->mesh_pm_id, ie->mesh_config + PM_OFFSET, 4) == 0 &&
66 		memcmp(sta->mesh_cc_id, ie->mesh_config + CC_OFFSET, 4) == 0)
67 		return true;
68 
69 	return false;
70 }
71 
72 /**
73  * mesh_peer_accepts_plinks - check if an mp is willing to establish peer links
74  *
75  * @ie: information elements of a management frame from the mesh peer
76  * @dev: local mesh interface
77  */
78 bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,
79 			      struct net_device *dev)
80 {
81 	return (*(ie->mesh_config + CAPAB_OFFSET) & ACCEPT_PLINKS) != 0;
82 }
83 
84 /**
85  * mesh_accept_plinks_update: update accepting_plink in local mesh beacons
86  *
87  * @sdata: mesh interface in which mesh beacons are going to be updated
88  */
89 void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)
90 {
91 	bool free_plinks;
92 
93 	/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
94 	 * the mesh interface might be able to establish plinks with peers that
95 	 * are already on the table but are not on PLINK_ESTAB state. However,
96 	 * in general the mesh interface is not accepting peer link requests
97 	 * from new peers, and that must be reflected in the beacon
98 	 */
99 	free_plinks = mesh_plink_availables(sdata);
100 
101 	if (free_plinks != sdata->u.sta.accepting_plinks)
102 		ieee80211_sta_timer((unsigned long) sdata);
103 }
104 
105 void mesh_ids_set_default(struct ieee80211_if_sta *sta)
106 {
107 	u8 def_id[4] = {0x00, 0x0F, 0xAC, 0xff};
108 
109 	memcpy(sta->mesh_pp_id, def_id, 4);
110 	memcpy(sta->mesh_pm_id, def_id, 4);
111 	memcpy(sta->mesh_cc_id, def_id, 4);
112 }
113 
114 int mesh_rmc_init(struct net_device *dev)
115 {
116 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
117 	int i;
118 
119 	sdata->u.sta.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);
120 	if (!sdata->u.sta.rmc)
121 		return -ENOMEM;
122 	sdata->u.sta.rmc->idx_mask = RMC_BUCKETS - 1;
123 	for (i = 0; i < RMC_BUCKETS; i++)
124 		INIT_LIST_HEAD(&sdata->u.sta.rmc->bucket[i].list);
125 	return 0;
126 }
127 
128 void mesh_rmc_free(struct net_device *dev)
129 {
130 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
131 	struct mesh_rmc *rmc = sdata->u.sta.rmc;
132 	struct rmc_entry *p, *n;
133 	int i;
134 
135 	if (!sdata->u.sta.rmc)
136 		return;
137 
138 	for (i = 0; i < RMC_BUCKETS; i++)
139 		list_for_each_entry_safe(p, n, &rmc->bucket[i].list, list) {
140 			list_del(&p->list);
141 			kmem_cache_free(rm_cache, p);
142 		}
143 
144 	kfree(rmc);
145 	sdata->u.sta.rmc = NULL;
146 }
147 
148 /**
149  * mesh_rmc_check - Check frame in recent multicast cache and add if absent.
150  *
151  * @sa:		source address
152  * @mesh_hdr:	mesh_header
153  *
154  * Returns: 0 if the frame is not in the cache, nonzero otherwise.
155  *
156  * Checks using the source address and the mesh sequence number if we have
157  * received this frame lately. If the frame is not in the cache, it is added to
158  * it.
159  */
160 int mesh_rmc_check(u8 *sa, struct ieee80211s_hdr *mesh_hdr,
161 		   struct net_device *dev)
162 {
163 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
164 	struct mesh_rmc *rmc = sdata->u.sta.rmc;
165 	u32 seqnum = 0;
166 	int entries = 0;
167 	u8 idx;
168 	struct rmc_entry *p, *n;
169 
170 	/* Don't care about endianness since only match matters */
171 	memcpy(&seqnum, &mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));
172 	idx = le32_to_cpu(mesh_hdr->seqnum) & rmc->idx_mask;
173 	list_for_each_entry_safe(p, n, &rmc->bucket[idx].list, list) {
174 		++entries;
175 		if (time_after(jiffies, p->exp_time) ||
176 				(entries == RMC_QUEUE_MAX_LEN)) {
177 			list_del(&p->list);
178 			kmem_cache_free(rm_cache, p);
179 			--entries;
180 		} else if ((seqnum == p->seqnum)
181 				&& (memcmp(sa, p->sa, ETH_ALEN) == 0))
182 			return -1;
183 	}
184 
185 	p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);
186 	if (!p) {
187 		printk(KERN_DEBUG "o11s: could not allocate RMC entry\n");
188 		return 0;
189 	}
190 	p->seqnum = seqnum;
191 	p->exp_time = jiffies + RMC_TIMEOUT;
192 	memcpy(p->sa, sa, ETH_ALEN);
193 	list_add(&p->list, &rmc->bucket[idx].list);
194 	return 0;
195 }
196 
197 void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev)
198 {
199 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
200 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
201 	struct ieee80211_supported_band *sband;
202 	u8 *pos;
203 	int len, i, rate;
204 
205 	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
206 	len = sband->n_bitrates;
207 	if (len > 8)
208 		len = 8;
209 	pos = skb_put(skb, len + 2);
210 	*pos++ = WLAN_EID_SUPP_RATES;
211 	*pos++ = len;
212 	for (i = 0; i < len; i++) {
213 		rate = sband->bitrates[i].bitrate;
214 		*pos++ = (u8) (rate / 5);
215 	}
216 
217 	if (sband->n_bitrates > len) {
218 		pos = skb_put(skb, sband->n_bitrates - len + 2);
219 		*pos++ = WLAN_EID_EXT_SUPP_RATES;
220 		*pos++ = sband->n_bitrates - len;
221 		for (i = len; i < sband->n_bitrates; i++) {
222 			rate = sband->bitrates[i].bitrate;
223 			*pos++ = (u8) (rate / 5);
224 		}
225 	}
226 
227 	pos = skb_put(skb, 2 + sdata->u.sta.mesh_id_len);
228 	*pos++ = WLAN_EID_MESH_ID;
229 	*pos++ = sdata->u.sta.mesh_id_len;
230 	if (sdata->u.sta.mesh_id_len)
231 		memcpy(pos, sdata->u.sta.mesh_id, sdata->u.sta.mesh_id_len);
232 
233 	pos = skb_put(skb, 21);
234 	*pos++ = WLAN_EID_MESH_CONFIG;
235 	*pos++ = MESH_CFG_LEN;
236 	/* Version */
237 	*pos++ = 1;
238 
239 	/* Active path selection protocol ID */
240 	memcpy(pos, sdata->u.sta.mesh_pp_id, 4);
241 	pos += 4;
242 
243 	/* Active path selection metric ID   */
244 	memcpy(pos, sdata->u.sta.mesh_pm_id, 4);
245 	pos += 4;
246 
247 	/* Congestion control mode identifier */
248 	memcpy(pos, sdata->u.sta.mesh_cc_id, 4);
249 	pos += 4;
250 
251 	/* Channel precedence:
252 	 * Not running simple channel unification protocol
253 	 */
254 	memset(pos, 0x00, 4);
255 	pos += 4;
256 
257 	/* Mesh capability */
258 	sdata->u.sta.accepting_plinks = mesh_plink_availables(sdata);
259 	*pos++ = sdata->u.sta.accepting_plinks ? ACCEPT_PLINKS : 0x00;
260 	*pos++ = 0x00;
261 
262 	return;
263 }
264 
265 u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl)
266 {
267 	/* Use last four bytes of hw addr and interface index as hash index */
268 	return jhash_2words(*(u32 *)(addr+2), dev->ifindex, tbl->hash_rnd)
269 		& tbl->hash_mask;
270 }
271 
272 u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len)
273 {
274 	if (!mesh_id_len)
275 		return 1;
276 	else if (mesh_id_len == 1)
277 		return (u8) mesh_id[0];
278 	else
279 		return (u8) (mesh_id[0] + 2 * mesh_id[1]);
280 }
281 
282 struct mesh_table *mesh_table_alloc(int size_order)
283 {
284 	int i;
285 	struct mesh_table *newtbl;
286 
287 	newtbl = kmalloc(sizeof(struct mesh_table), GFP_KERNEL);
288 	if (!newtbl)
289 		return NULL;
290 
291 	newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
292 			(1 << size_order), GFP_KERNEL);
293 
294 	if (!newtbl->hash_buckets) {
295 		kfree(newtbl);
296 		return NULL;
297 	}
298 
299 	newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
300 			(1 << size_order), GFP_KERNEL);
301 	if (!newtbl->hashwlock) {
302 		kfree(newtbl->hash_buckets);
303 		kfree(newtbl);
304 		return NULL;
305 	}
306 
307 	newtbl->size_order = size_order;
308 	newtbl->hash_mask = (1 << size_order) - 1;
309 	atomic_set(&newtbl->entries,  0);
310 	get_random_bytes(&newtbl->hash_rnd,
311 			sizeof(newtbl->hash_rnd));
312 	for (i = 0; i <= newtbl->hash_mask; i++)
313 		spin_lock_init(&newtbl->hashwlock[i]);
314 
315 	return newtbl;
316 }
317 
318 static void __mesh_table_free(struct mesh_table *tbl)
319 {
320 	kfree(tbl->hash_buckets);
321 	kfree(tbl->hashwlock);
322 	kfree(tbl);
323 }
324 
325 void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
326 {
327 	struct hlist_head *mesh_hash;
328 	struct hlist_node *p, *q;
329 	int i;
330 
331 	mesh_hash = tbl->hash_buckets;
332 	for (i = 0; i <= tbl->hash_mask; i++) {
333 		spin_lock(&tbl->hashwlock[i]);
334 		hlist_for_each_safe(p, q, &mesh_hash[i]) {
335 			tbl->free_node(p, free_leafs);
336 			atomic_dec(&tbl->entries);
337 		}
338 		spin_unlock(&tbl->hashwlock[i]);
339 	}
340 	__mesh_table_free(tbl);
341 }
342 
343 static void ieee80211_mesh_path_timer(unsigned long data)
344 {
345 	struct ieee80211_sub_if_data *sdata =
346 		(struct ieee80211_sub_if_data *) data;
347 	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
348 	struct ieee80211_local *local = wdev_priv(&sdata->wdev);
349 
350 	queue_work(local->hw.workqueue, &ifsta->work);
351 }
352 
353 struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
354 {
355 	struct mesh_table *newtbl;
356 	struct hlist_head *oldhash;
357 	struct hlist_node *p, *q;
358 	int i;
359 
360 	if (atomic_read(&tbl->entries)
361 			< tbl->mean_chain_len * (tbl->hash_mask + 1))
362 		goto endgrow;
363 
364 	newtbl = mesh_table_alloc(tbl->size_order + 1);
365 	if (!newtbl)
366 		goto endgrow;
367 
368 	newtbl->free_node = tbl->free_node;
369 	newtbl->mean_chain_len = tbl->mean_chain_len;
370 	newtbl->copy_node = tbl->copy_node;
371 	atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
372 
373 	oldhash = tbl->hash_buckets;
374 	for (i = 0; i <= tbl->hash_mask; i++)
375 		hlist_for_each(p, &oldhash[i])
376 			if (tbl->copy_node(p, newtbl) < 0)
377 				goto errcopy;
378 
379 	return newtbl;
380 
381 errcopy:
382 	for (i = 0; i <= newtbl->hash_mask; i++) {
383 		hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
384 			tbl->free_node(p, 0);
385 	}
386 	__mesh_table_free(tbl);
387 endgrow:
388 	return NULL;
389 }
390 
391 /**
392  * ieee80211_new_mesh_header - create a new mesh header
393  * @meshhdr:    uninitialized mesh header
394  * @sdata:	mesh interface to be used
395  *
396  * Return the header length.
397  */
398 int ieee80211_new_mesh_header(struct ieee80211s_hdr *meshhdr,
399 		struct ieee80211_sub_if_data *sdata)
400 {
401 	meshhdr->flags = 0;
402 	meshhdr->ttl = sdata->u.sta.mshcfg.dot11MeshTTL;
403 	put_unaligned(cpu_to_le32(sdata->u.sta.mesh_seqnum), &meshhdr->seqnum);
404 	sdata->u.sta.mesh_seqnum++;
405 
406 	return 6;
407 }
408 
409 void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
410 {
411 	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
412 
413 	ifsta->mshcfg.dot11MeshRetryTimeout = MESH_RET_T;
414 	ifsta->mshcfg.dot11MeshConfirmTimeout = MESH_CONF_T;
415 	ifsta->mshcfg.dot11MeshHoldingTimeout = MESH_HOLD_T;
416 	ifsta->mshcfg.dot11MeshMaxRetries = MESH_MAX_RETR;
417 	ifsta->mshcfg.dot11MeshTTL = MESH_TTL;
418 	ifsta->mshcfg.auto_open_plinks = true;
419 	ifsta->mshcfg.dot11MeshMaxPeerLinks =
420 		MESH_MAX_ESTAB_PLINKS;
421 	ifsta->mshcfg.dot11MeshHWMPactivePathTimeout =
422 		MESH_PATH_TIMEOUT;
423 	ifsta->mshcfg.dot11MeshHWMPpreqMinInterval =
424 		MESH_PREQ_MIN_INT;
425 	ifsta->mshcfg.dot11MeshHWMPnetDiameterTraversalTime =
426 		MESH_DIAM_TRAVERSAL_TIME;
427 	ifsta->mshcfg.dot11MeshHWMPmaxPREQretries =
428 		MESH_MAX_PREQ_RETRIES;
429 	ifsta->mshcfg.path_refresh_time =
430 		MESH_PATH_REFRESH_TIME;
431 	ifsta->mshcfg.min_discovery_timeout =
432 		MESH_MIN_DISCOVERY_TIMEOUT;
433 	ifsta->accepting_plinks = true;
434 	ifsta->preq_id = 0;
435 	ifsta->dsn = 0;
436 	atomic_set(&ifsta->mpaths, 0);
437 	mesh_rmc_init(sdata->dev);
438 	ifsta->last_preq = jiffies;
439 	/* Allocate all mesh structures when creating the first mesh interface. */
440 	if (!mesh_allocated)
441 		ieee80211s_init();
442 	mesh_ids_set_default(ifsta);
443 	setup_timer(&ifsta->mesh_path_timer,
444 		    ieee80211_mesh_path_timer,
445 		    (unsigned long) sdata);
446 	INIT_LIST_HEAD(&ifsta->preq_queue.list);
447 	spin_lock_init(&ifsta->mesh_preq_queue_lock);
448 }
449