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/slab.h>
11 #include <linux/etherdevice.h>
12 #include <asm/unaligned.h>
13 #include "wme.h"
14 #include "mesh.h"
15 
16 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
17 #define mhwmp_dbg(fmt, args...) \
18 	printk(KERN_DEBUG "Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
19 #else
20 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
21 #endif
22 
23 #define TEST_FRAME_LEN	8192
24 #define MAX_METRIC	0xffffffff
25 #define ARITH_SHIFT	8
26 
27 /* Number of frames buffered per destination for unresolved destinations */
28 #define MESH_FRAME_QUEUE_LEN	10
29 #define MAX_PREQ_QUEUE_LEN	64
30 
31 /* Destination only */
32 #define MP_F_DO	0x1
33 /* Reply and forward */
34 #define MP_F_RF	0x2
35 /* Unknown Sequence Number */
36 #define MP_F_USN    0x01
37 /* Reason code Present */
38 #define MP_F_RCODE  0x02
39 
40 static void mesh_queue_preq(struct mesh_path *, u8);
41 
u32_field_get(u8 * preq_elem,int offset,bool ae)42 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
43 {
44 	if (ae)
45 		offset += 6;
46 	return get_unaligned_le32(preq_elem + offset);
47 }
48 
u16_field_get(u8 * preq_elem,int offset,bool ae)49 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
50 {
51 	if (ae)
52 		offset += 6;
53 	return get_unaligned_le16(preq_elem + offset);
54 }
55 
56 /* HWMP IE processing macros */
57 #define AE_F			(1<<6)
58 #define AE_F_SET(x)		(*x & AE_F)
59 #define PREQ_IE_FLAGS(x)	(*(x))
60 #define PREQ_IE_HOPCOUNT(x)	(*(x + 1))
61 #define PREQ_IE_TTL(x)		(*(x + 2))
62 #define PREQ_IE_PREQ_ID(x)	u32_field_get(x, 3, 0)
63 #define PREQ_IE_ORIG_ADDR(x)	(x + 7)
64 #define PREQ_IE_ORIG_SN(x)	u32_field_get(x, 13, 0)
65 #define PREQ_IE_LIFETIME(x)	u32_field_get(x, 17, AE_F_SET(x))
66 #define PREQ_IE_METRIC(x) 	u32_field_get(x, 21, AE_F_SET(x))
67 #define PREQ_IE_TARGET_F(x)	(*(AE_F_SET(x) ? x + 32 : x + 26))
68 #define PREQ_IE_TARGET_ADDR(x) 	(AE_F_SET(x) ? x + 33 : x + 27)
69 #define PREQ_IE_TARGET_SN(x) 	u32_field_get(x, 33, AE_F_SET(x))
70 
71 
72 #define PREP_IE_FLAGS(x)	PREQ_IE_FLAGS(x)
73 #define PREP_IE_HOPCOUNT(x)	PREQ_IE_HOPCOUNT(x)
74 #define PREP_IE_TTL(x)		PREQ_IE_TTL(x)
75 #define PREP_IE_ORIG_ADDR(x)	(AE_F_SET(x) ? x + 27 : x + 21)
76 #define PREP_IE_ORIG_SN(x)	u32_field_get(x, 27, AE_F_SET(x))
77 #define PREP_IE_LIFETIME(x)	u32_field_get(x, 13, AE_F_SET(x))
78 #define PREP_IE_METRIC(x)	u32_field_get(x, 17, AE_F_SET(x))
79 #define PREP_IE_TARGET_ADDR(x)	(x + 3)
80 #define PREP_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
81 
82 #define PERR_IE_TTL(x)		(*(x))
83 #define PERR_IE_TARGET_FLAGS(x)	(*(x + 2))
84 #define PERR_IE_TARGET_ADDR(x)	(x + 3)
85 #define PERR_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
86 #define PERR_IE_TARGET_RCODE(x)	u16_field_get(x, 13, 0)
87 
88 #define MSEC_TO_TU(x) (x*1000/1024)
89 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
90 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
91 
92 #define net_traversal_jiffies(s) \
93 	msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
94 #define default_lifetime(s) \
95 	MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
96 #define min_preq_int_jiff(s) \
97 	(msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
98 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
99 #define disc_timeout_jiff(s) \
100 	msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
101 
102 enum mpath_frame_type {
103 	MPATH_PREQ = 0,
104 	MPATH_PREP,
105 	MPATH_PERR,
106 	MPATH_RANN
107 };
108 
109 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
110 
mesh_path_sel_frame_tx(enum mpath_frame_type action,u8 flags,u8 * orig_addr,__le32 orig_sn,u8 target_flags,u8 * target,__le32 target_sn,const u8 * da,u8 hop_count,u8 ttl,__le32 lifetime,__le32 metric,__le32 preq_id,struct ieee80211_sub_if_data * sdata)111 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
112 		u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
113 		__le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
114 		__le32 lifetime, __le32 metric, __le32 preq_id,
115 		struct ieee80211_sub_if_data *sdata)
116 {
117 	struct ieee80211_local *local = sdata->local;
118 	struct sk_buff *skb;
119 	struct ieee80211_mgmt *mgmt;
120 	u8 *pos, ie_len;
121 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
122 		      sizeof(mgmt->u.action.u.mesh_action);
123 
124 	skb = dev_alloc_skb(local->tx_headroom +
125 			    hdr_len +
126 			    2 + 37); /* max HWMP IE */
127 	if (!skb)
128 		return -1;
129 	skb_reserve(skb, local->tx_headroom);
130 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
131 	memset(mgmt, 0, hdr_len);
132 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
133 					  IEEE80211_STYPE_ACTION);
134 
135 	memcpy(mgmt->da, da, ETH_ALEN);
136 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
137 	/* BSSID == SA */
138 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
139 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
140 	mgmt->u.action.u.mesh_action.action_code =
141 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
142 
143 	switch (action) {
144 	case MPATH_PREQ:
145 		mhwmp_dbg("sending PREQ to %pM", target);
146 		ie_len = 37;
147 		pos = skb_put(skb, 2 + ie_len);
148 		*pos++ = WLAN_EID_PREQ;
149 		break;
150 	case MPATH_PREP:
151 		mhwmp_dbg("sending PREP to %pM", target);
152 		ie_len = 31;
153 		pos = skb_put(skb, 2 + ie_len);
154 		*pos++ = WLAN_EID_PREP;
155 		break;
156 	case MPATH_RANN:
157 		mhwmp_dbg("sending RANN from %pM", orig_addr);
158 		ie_len = sizeof(struct ieee80211_rann_ie);
159 		pos = skb_put(skb, 2 + ie_len);
160 		*pos++ = WLAN_EID_RANN;
161 		break;
162 	default:
163 		kfree_skb(skb);
164 		return -ENOTSUPP;
165 		break;
166 	}
167 	*pos++ = ie_len;
168 	*pos++ = flags;
169 	*pos++ = hop_count;
170 	*pos++ = ttl;
171 	if (action == MPATH_PREP) {
172 		memcpy(pos, target, ETH_ALEN);
173 		pos += ETH_ALEN;
174 		memcpy(pos, &target_sn, 4);
175 		pos += 4;
176 	} else {
177 		if (action == MPATH_PREQ) {
178 			memcpy(pos, &preq_id, 4);
179 			pos += 4;
180 		}
181 		memcpy(pos, orig_addr, ETH_ALEN);
182 		pos += ETH_ALEN;
183 		memcpy(pos, &orig_sn, 4);
184 		pos += 4;
185 	}
186 	memcpy(pos, &lifetime, 4);	/* interval for RANN */
187 	pos += 4;
188 	memcpy(pos, &metric, 4);
189 	pos += 4;
190 	if (action == MPATH_PREQ) {
191 		*pos++ = 1; /* destination count */
192 		*pos++ = target_flags;
193 		memcpy(pos, target, ETH_ALEN);
194 		pos += ETH_ALEN;
195 		memcpy(pos, &target_sn, 4);
196 		pos += 4;
197 	} else if (action == MPATH_PREP) {
198 		memcpy(pos, orig_addr, ETH_ALEN);
199 		pos += ETH_ALEN;
200 		memcpy(pos, &orig_sn, 4);
201 		pos += 4;
202 	}
203 
204 	ieee80211_tx_skb(sdata, skb);
205 	return 0;
206 }
207 
208 
209 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
210  *  headroom in case the frame is encrypted. */
prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)211 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
212 		struct sk_buff *skb)
213 {
214 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
215 
216 	skb_set_mac_header(skb, 0);
217 	skb_set_network_header(skb, 0);
218 	skb_set_transport_header(skb, 0);
219 
220 	/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
221 	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
222 	skb->priority = 7;
223 
224 	info->control.vif = &sdata->vif;
225 	ieee80211_set_qos_hdr(sdata, skb);
226 }
227 
228 /**
229  * mesh_send_path error - Sends a PERR mesh management frame
230  *
231  * @target: broken destination
232  * @target_sn: SN of the broken destination
233  * @target_rcode: reason code for this PERR
234  * @ra: node this frame is addressed to
235  *
236  * Note: This function may be called with driver locks taken that the driver
237  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
238  * frame directly but add it to the pending queue instead.
239  */
mesh_path_error_tx(u8 ttl,u8 * target,__le32 target_sn,__le16 target_rcode,const u8 * ra,struct ieee80211_sub_if_data * sdata)240 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
241 		       __le16 target_rcode, const u8 *ra,
242 		       struct ieee80211_sub_if_data *sdata)
243 {
244 	struct ieee80211_local *local = sdata->local;
245 	struct sk_buff *skb;
246 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
247 	struct ieee80211_mgmt *mgmt;
248 	u8 *pos, ie_len;
249 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
250 		      sizeof(mgmt->u.action.u.mesh_action);
251 
252 	if (time_before(jiffies, ifmsh->next_perr))
253 		return -EAGAIN;
254 
255 	skb = dev_alloc_skb(local->tx_headroom +
256 			    hdr_len +
257 			    2 + 15 /* PERR IE */);
258 	if (!skb)
259 		return -1;
260 	skb_reserve(skb, local->tx_headroom);
261 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
262 	memset(mgmt, 0, hdr_len);
263 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
264 					  IEEE80211_STYPE_ACTION);
265 
266 	memcpy(mgmt->da, ra, ETH_ALEN);
267 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
268 	/* BSSID == SA */
269 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
270 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
271 	mgmt->u.action.u.mesh_action.action_code =
272 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
273 	ie_len = 15;
274 	pos = skb_put(skb, 2 + ie_len);
275 	*pos++ = WLAN_EID_PERR;
276 	*pos++ = ie_len;
277 	/* ttl */
278 	*pos++ = ttl;
279 	/* number of destinations */
280 	*pos++ = 1;
281 	/*
282 	 * flags bit, bit 1 is unset if we know the sequence number and
283 	 * bit 2 is set if we have a reason code
284 	 */
285 	*pos = 0;
286 	if (!target_sn)
287 		*pos |= MP_F_USN;
288 	if (target_rcode)
289 		*pos |= MP_F_RCODE;
290 	pos++;
291 	memcpy(pos, target, ETH_ALEN);
292 	pos += ETH_ALEN;
293 	memcpy(pos, &target_sn, 4);
294 	pos += 4;
295 	memcpy(pos, &target_rcode, 2);
296 
297 	/* see note in function header */
298 	prepare_frame_for_deferred_tx(sdata, skb);
299 	ifmsh->next_perr = TU_TO_EXP_TIME(
300 				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
301 	ieee80211_add_pending_skb(local, skb);
302 	return 0;
303 }
304 
ieee80211s_update_metric(struct ieee80211_local * local,struct sta_info * stainfo,struct sk_buff * skb)305 void ieee80211s_update_metric(struct ieee80211_local *local,
306 		struct sta_info *stainfo, struct sk_buff *skb)
307 {
308 	struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
309 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
310 	int failed;
311 
312 	if (!ieee80211_is_data(hdr->frame_control))
313 		return;
314 
315 	failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
316 
317 	/* moving average, scaled to 100 */
318 	stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
319 	if (stainfo->fail_avg > 95)
320 		mesh_plink_broken(stainfo);
321 }
322 
airtime_link_metric_get(struct ieee80211_local * local,struct sta_info * sta)323 static u32 airtime_link_metric_get(struct ieee80211_local *local,
324 				   struct sta_info *sta)
325 {
326 	struct ieee80211_supported_band *sband;
327 	struct rate_info rinfo;
328 	/* This should be adjusted for each device */
329 	int device_constant = 1 << ARITH_SHIFT;
330 	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
331 	int s_unit = 1 << ARITH_SHIFT;
332 	int rate, err;
333 	u32 tx_time, estimated_retx;
334 	u64 result;
335 
336 	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
337 
338 	if (sta->fail_avg >= 100)
339 		return MAX_METRIC;
340 
341 	sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
342 	rate = cfg80211_calculate_bitrate(&rinfo);
343 	if (WARN_ON(!rate))
344 		return MAX_METRIC;
345 
346 	err = (sta->fail_avg << ARITH_SHIFT) / 100;
347 
348 	/* bitrate is in units of 100 Kbps, while we need rate in units of
349 	 * 1Mbps. This will be corrected on tx_time computation.
350 	 */
351 	tx_time = (device_constant + 10 * test_frame_len / rate);
352 	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
353 	result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
354 	return (u32)result;
355 }
356 
357 /**
358  * hwmp_route_info_get - Update routing info to originator and transmitter
359  *
360  * @sdata: local mesh subif
361  * @mgmt: mesh management frame
362  * @hwmp_ie: hwmp information element (PREP or PREQ)
363  *
364  * This function updates the path routing information to the originator and the
365  * transmitter of a HWMP PREQ or PREP frame.
366  *
367  * Returns: metric to frame originator or 0 if the frame should not be further
368  * processed
369  *
370  * Notes: this function is the only place (besides user-provided info) where
371  * path routing information is updated.
372  */
hwmp_route_info_get(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,u8 * hwmp_ie,enum mpath_frame_type action)373 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
374 			    struct ieee80211_mgmt *mgmt,
375 			    u8 *hwmp_ie, enum mpath_frame_type action)
376 {
377 	struct ieee80211_local *local = sdata->local;
378 	struct mesh_path *mpath;
379 	struct sta_info *sta;
380 	bool fresh_info;
381 	u8 *orig_addr, *ta;
382 	u32 orig_sn, orig_metric;
383 	unsigned long orig_lifetime, exp_time;
384 	u32 last_hop_metric, new_metric;
385 	bool process = true;
386 
387 	rcu_read_lock();
388 	sta = sta_info_get(sdata, mgmt->sa);
389 	if (!sta) {
390 		rcu_read_unlock();
391 		return 0;
392 	}
393 
394 	last_hop_metric = airtime_link_metric_get(local, sta);
395 	/* Update and check originator routing info */
396 	fresh_info = true;
397 
398 	switch (action) {
399 	case MPATH_PREQ:
400 		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
401 		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
402 		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
403 		orig_metric = PREQ_IE_METRIC(hwmp_ie);
404 		break;
405 	case MPATH_PREP:
406 		/* Originator here refers to the MP that was the target in the
407 		 * Path Request. We divert from the nomenclature in the draft
408 		 * so that we can easily use a single function to gather path
409 		 * information from both PREQ and PREP frames.
410 		 */
411 		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
412 		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
413 		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
414 		orig_metric = PREP_IE_METRIC(hwmp_ie);
415 		break;
416 	default:
417 		rcu_read_unlock();
418 		return 0;
419 	}
420 	new_metric = orig_metric + last_hop_metric;
421 	if (new_metric < orig_metric)
422 		new_metric = MAX_METRIC;
423 	exp_time = TU_TO_EXP_TIME(orig_lifetime);
424 
425 	if (compare_ether_addr(orig_addr, sdata->vif.addr) == 0) {
426 		/* This MP is the originator, we are not interested in this
427 		 * frame, except for updating transmitter's path info.
428 		 */
429 		process = false;
430 		fresh_info = false;
431 	} else {
432 		mpath = mesh_path_lookup(orig_addr, sdata);
433 		if (mpath) {
434 			spin_lock_bh(&mpath->state_lock);
435 			if (mpath->flags & MESH_PATH_FIXED)
436 				fresh_info = false;
437 			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
438 			    (mpath->flags & MESH_PATH_SN_VALID)) {
439 				if (SN_GT(mpath->sn, orig_sn) ||
440 				    (mpath->sn == orig_sn &&
441 				     new_metric >= mpath->metric)) {
442 					process = false;
443 					fresh_info = false;
444 				}
445 			}
446 		} else {
447 			mesh_path_add(orig_addr, sdata);
448 			mpath = mesh_path_lookup(orig_addr, sdata);
449 			if (!mpath) {
450 				rcu_read_unlock();
451 				return 0;
452 			}
453 			spin_lock_bh(&mpath->state_lock);
454 		}
455 
456 		if (fresh_info) {
457 			mesh_path_assign_nexthop(mpath, sta);
458 			mpath->flags |= MESH_PATH_SN_VALID;
459 			mpath->metric = new_metric;
460 			mpath->sn = orig_sn;
461 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
462 					  ?  mpath->exp_time : exp_time;
463 			mesh_path_activate(mpath);
464 			spin_unlock_bh(&mpath->state_lock);
465 			mesh_path_tx_pending(mpath);
466 			/* draft says preq_id should be saved to, but there does
467 			 * not seem to be any use for it, skipping by now
468 			 */
469 		} else
470 			spin_unlock_bh(&mpath->state_lock);
471 	}
472 
473 	/* Update and check transmitter routing info */
474 	ta = mgmt->sa;
475 	if (compare_ether_addr(orig_addr, ta) == 0)
476 		fresh_info = false;
477 	else {
478 		fresh_info = true;
479 
480 		mpath = mesh_path_lookup(ta, sdata);
481 		if (mpath) {
482 			spin_lock_bh(&mpath->state_lock);
483 			if ((mpath->flags & MESH_PATH_FIXED) ||
484 				((mpath->flags & MESH_PATH_ACTIVE) &&
485 					(last_hop_metric > mpath->metric)))
486 				fresh_info = false;
487 		} else {
488 			mesh_path_add(ta, sdata);
489 			mpath = mesh_path_lookup(ta, sdata);
490 			if (!mpath) {
491 				rcu_read_unlock();
492 				return 0;
493 			}
494 			spin_lock_bh(&mpath->state_lock);
495 		}
496 
497 		if (fresh_info) {
498 			mesh_path_assign_nexthop(mpath, sta);
499 			mpath->metric = last_hop_metric;
500 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
501 					  ?  mpath->exp_time : exp_time;
502 			mesh_path_activate(mpath);
503 			spin_unlock_bh(&mpath->state_lock);
504 			mesh_path_tx_pending(mpath);
505 		} else
506 			spin_unlock_bh(&mpath->state_lock);
507 	}
508 
509 	rcu_read_unlock();
510 
511 	return process ? new_metric : 0;
512 }
513 
hwmp_preq_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,u8 * preq_elem,u32 metric)514 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
515 				    struct ieee80211_mgmt *mgmt,
516 				    u8 *preq_elem, u32 metric)
517 {
518 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
519 	struct mesh_path *mpath = NULL;
520 	u8 *target_addr, *orig_addr;
521 	const u8 *da;
522 	u8 target_flags, ttl;
523 	u32 orig_sn, target_sn, lifetime;
524 	bool reply = false;
525 	bool forward = true;
526 
527 	/* Update target SN, if present */
528 	target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
529 	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
530 	target_sn = PREQ_IE_TARGET_SN(preq_elem);
531 	orig_sn = PREQ_IE_ORIG_SN(preq_elem);
532 	target_flags = PREQ_IE_TARGET_F(preq_elem);
533 
534 	mhwmp_dbg("received PREQ from %pM", orig_addr);
535 
536 	if (compare_ether_addr(target_addr, sdata->vif.addr) == 0) {
537 		mhwmp_dbg("PREQ is for us");
538 		forward = false;
539 		reply = true;
540 		metric = 0;
541 		if (time_after(jiffies, ifmsh->last_sn_update +
542 					net_traversal_jiffies(sdata)) ||
543 		    time_before(jiffies, ifmsh->last_sn_update)) {
544 			target_sn = ++ifmsh->sn;
545 			ifmsh->last_sn_update = jiffies;
546 		}
547 	} else {
548 		rcu_read_lock();
549 		mpath = mesh_path_lookup(target_addr, sdata);
550 		if (mpath) {
551 			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
552 					SN_LT(mpath->sn, target_sn)) {
553 				mpath->sn = target_sn;
554 				mpath->flags |= MESH_PATH_SN_VALID;
555 			} else if ((!(target_flags & MP_F_DO)) &&
556 					(mpath->flags & MESH_PATH_ACTIVE)) {
557 				reply = true;
558 				metric = mpath->metric;
559 				target_sn = mpath->sn;
560 				if (target_flags & MP_F_RF)
561 					target_flags |= MP_F_DO;
562 				else
563 					forward = false;
564 			}
565 		}
566 		rcu_read_unlock();
567 	}
568 
569 	if (reply) {
570 		lifetime = PREQ_IE_LIFETIME(preq_elem);
571 		ttl = ifmsh->mshcfg.element_ttl;
572 		if (ttl != 0) {
573 			mhwmp_dbg("replying to the PREQ");
574 			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
575 				cpu_to_le32(orig_sn), 0, target_addr,
576 				cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
577 				cpu_to_le32(lifetime), cpu_to_le32(metric),
578 				0, sdata);
579 		} else
580 			ifmsh->mshstats.dropped_frames_ttl++;
581 	}
582 
583 	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
584 		u32 preq_id;
585 		u8 hopcount, flags;
586 
587 		ttl = PREQ_IE_TTL(preq_elem);
588 		lifetime = PREQ_IE_LIFETIME(preq_elem);
589 		if (ttl <= 1) {
590 			ifmsh->mshstats.dropped_frames_ttl++;
591 			return;
592 		}
593 		mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
594 		--ttl;
595 		flags = PREQ_IE_FLAGS(preq_elem);
596 		preq_id = PREQ_IE_PREQ_ID(preq_elem);
597 		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
598 		da = (mpath && mpath->is_root) ?
599 			mpath->rann_snd_addr : broadcast_addr;
600 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
601 				cpu_to_le32(orig_sn), target_flags, target_addr,
602 				cpu_to_le32(target_sn), da,
603 				hopcount, ttl, cpu_to_le32(lifetime),
604 				cpu_to_le32(metric), cpu_to_le32(preq_id),
605 				sdata);
606 		ifmsh->mshstats.fwded_mcast++;
607 		ifmsh->mshstats.fwded_frames++;
608 	}
609 }
610 
611 
612 static inline struct sta_info *
next_hop_deref_protected(struct mesh_path * mpath)613 next_hop_deref_protected(struct mesh_path *mpath)
614 {
615 	return rcu_dereference_protected(mpath->next_hop,
616 					 lockdep_is_held(&mpath->state_lock));
617 }
618 
619 
hwmp_prep_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,u8 * prep_elem,u32 metric)620 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
621 				    struct ieee80211_mgmt *mgmt,
622 				    u8 *prep_elem, u32 metric)
623 {
624 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
625 	struct mesh_path *mpath;
626 	u8 *target_addr, *orig_addr;
627 	u8 ttl, hopcount, flags;
628 	u8 next_hop[ETH_ALEN];
629 	u32 target_sn, orig_sn, lifetime;
630 
631 	mhwmp_dbg("received PREP from %pM", PREP_IE_ORIG_ADDR(prep_elem));
632 
633 	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
634 	if (compare_ether_addr(orig_addr, sdata->vif.addr) == 0)
635 		/* destination, no forwarding required */
636 		return;
637 
638 	if (!ifmsh->mshcfg.dot11MeshForwarding)
639 		return;
640 
641 	ttl = PREP_IE_TTL(prep_elem);
642 	if (ttl <= 1) {
643 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
644 		return;
645 	}
646 
647 	rcu_read_lock();
648 	mpath = mesh_path_lookup(orig_addr, sdata);
649 	if (mpath)
650 		spin_lock_bh(&mpath->state_lock);
651 	else
652 		goto fail;
653 	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
654 		spin_unlock_bh(&mpath->state_lock);
655 		goto fail;
656 	}
657 	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
658 	spin_unlock_bh(&mpath->state_lock);
659 	--ttl;
660 	flags = PREP_IE_FLAGS(prep_elem);
661 	lifetime = PREP_IE_LIFETIME(prep_elem);
662 	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
663 	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
664 	target_sn = PREP_IE_TARGET_SN(prep_elem);
665 	orig_sn = PREP_IE_ORIG_SN(prep_elem);
666 
667 	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
668 		cpu_to_le32(orig_sn), 0, target_addr,
669 		cpu_to_le32(target_sn), next_hop, hopcount,
670 		ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
671 		0, sdata);
672 	rcu_read_unlock();
673 
674 	sdata->u.mesh.mshstats.fwded_unicast++;
675 	sdata->u.mesh.mshstats.fwded_frames++;
676 	return;
677 
678 fail:
679 	rcu_read_unlock();
680 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
681 }
682 
hwmp_perr_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,u8 * perr_elem)683 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
684 			     struct ieee80211_mgmt *mgmt, u8 *perr_elem)
685 {
686 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
687 	struct mesh_path *mpath;
688 	u8 ttl;
689 	u8 *ta, *target_addr;
690 	u32 target_sn;
691 	u16 target_rcode;
692 
693 	ta = mgmt->sa;
694 	ttl = PERR_IE_TTL(perr_elem);
695 	if (ttl <= 1) {
696 		ifmsh->mshstats.dropped_frames_ttl++;
697 		return;
698 	}
699 	ttl--;
700 	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
701 	target_sn = PERR_IE_TARGET_SN(perr_elem);
702 	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
703 
704 	rcu_read_lock();
705 	mpath = mesh_path_lookup(target_addr, sdata);
706 	if (mpath) {
707 		struct sta_info *sta;
708 
709 		spin_lock_bh(&mpath->state_lock);
710 		sta = next_hop_deref_protected(mpath);
711 		if (mpath->flags & MESH_PATH_ACTIVE &&
712 		    compare_ether_addr(ta, sta->sta.addr) == 0 &&
713 		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
714 		    SN_GT(target_sn, mpath->sn))) {
715 			mpath->flags &= ~MESH_PATH_ACTIVE;
716 			mpath->sn = target_sn;
717 			spin_unlock_bh(&mpath->state_lock);
718 			if (!ifmsh->mshcfg.dot11MeshForwarding)
719 				goto endperr;
720 			mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
721 					   cpu_to_le16(target_rcode),
722 					   broadcast_addr, sdata);
723 		} else
724 			spin_unlock_bh(&mpath->state_lock);
725 	}
726 endperr:
727 	rcu_read_unlock();
728 }
729 
hwmp_rann_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,struct ieee80211_rann_ie * rann)730 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
731 				struct ieee80211_mgmt *mgmt,
732 				struct ieee80211_rann_ie *rann)
733 {
734 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
735 	struct mesh_path *mpath;
736 	u8 ttl, flags, hopcount;
737 	u8 *orig_addr;
738 	u32 orig_sn, metric;
739 	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
740 	bool root_is_gate;
741 
742 	ttl = rann->rann_ttl;
743 	if (ttl <= 1) {
744 		ifmsh->mshstats.dropped_frames_ttl++;
745 		return;
746 	}
747 	ttl--;
748 	flags = rann->rann_flags;
749 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
750 	orig_addr = rann->rann_addr;
751 	orig_sn = rann->rann_seq;
752 	hopcount = rann->rann_hopcount;
753 	hopcount++;
754 	metric = rann->rann_metric;
755 
756 	/*  Ignore our own RANNs */
757 	if (compare_ether_addr(orig_addr, sdata->vif.addr) == 0)
758 		return;
759 
760 	mhwmp_dbg("received RANN from %pM via neighbour %pM (is_gate=%d)",
761 			orig_addr, mgmt->sa, root_is_gate);
762 
763 	rcu_read_lock();
764 	mpath = mesh_path_lookup(orig_addr, sdata);
765 	if (!mpath) {
766 		mesh_path_add(orig_addr, sdata);
767 		mpath = mesh_path_lookup(orig_addr, sdata);
768 		if (!mpath) {
769 			rcu_read_unlock();
770 			sdata->u.mesh.mshstats.dropped_frames_no_route++;
771 			return;
772 		}
773 	}
774 
775 	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
776 	     time_after(jiffies, mpath->exp_time - 1*HZ)) &&
777 	     !(mpath->flags & MESH_PATH_FIXED)) {
778 		mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
779 							       orig_addr);
780 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
781 	}
782 
783 	if (mpath->sn < orig_sn && ifmsh->mshcfg.dot11MeshForwarding) {
784 		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
785 				       cpu_to_le32(orig_sn),
786 				       0, NULL, 0, broadcast_addr,
787 				       hopcount, ttl, cpu_to_le32(interval),
788 				       cpu_to_le32(metric + mpath->metric),
789 				       0, sdata);
790 		mpath->sn = orig_sn;
791 	}
792 
793 	/* Using individually addressed PREQ for root node */
794 	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
795 	mpath->is_root = true;
796 
797 	if (root_is_gate)
798 		mesh_path_add_gate(mpath);
799 
800 	rcu_read_unlock();
801 }
802 
803 
mesh_rx_path_sel_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len)804 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
805 			    struct ieee80211_mgmt *mgmt,
806 			    size_t len)
807 {
808 	struct ieee802_11_elems elems;
809 	size_t baselen;
810 	u32 last_hop_metric;
811 	struct sta_info *sta;
812 
813 	/* need action_code */
814 	if (len < IEEE80211_MIN_ACTION_SIZE + 1)
815 		return;
816 
817 	rcu_read_lock();
818 	sta = sta_info_get(sdata, mgmt->sa);
819 	if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
820 		rcu_read_unlock();
821 		return;
822 	}
823 	rcu_read_unlock();
824 
825 	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
826 	ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
827 			len - baselen, &elems);
828 
829 	if (elems.preq) {
830 		if (elems.preq_len != 37)
831 			/* Right now we support just 1 destination and no AE */
832 			return;
833 		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
834 						      MPATH_PREQ);
835 		if (last_hop_metric)
836 			hwmp_preq_frame_process(sdata, mgmt, elems.preq,
837 						last_hop_metric);
838 	}
839 	if (elems.prep) {
840 		if (elems.prep_len != 31)
841 			/* Right now we support no AE */
842 			return;
843 		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
844 						      MPATH_PREP);
845 		if (last_hop_metric)
846 			hwmp_prep_frame_process(sdata, mgmt, elems.prep,
847 						last_hop_metric);
848 	}
849 	if (elems.perr) {
850 		if (elems.perr_len != 15)
851 			/* Right now we support only one destination per PERR */
852 			return;
853 		hwmp_perr_frame_process(sdata, mgmt, elems.perr);
854 	}
855 	if (elems.rann)
856 		hwmp_rann_frame_process(sdata, mgmt, elems.rann);
857 }
858 
859 /**
860  * mesh_queue_preq - queue a PREQ to a given destination
861  *
862  * @mpath: mesh path to discover
863  * @flags: special attributes of the PREQ to be sent
864  *
865  * Locking: the function must be called from within a rcu read lock block.
866  *
867  */
mesh_queue_preq(struct mesh_path * mpath,u8 flags)868 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
869 {
870 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
871 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
872 	struct mesh_preq_queue *preq_node;
873 
874 	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
875 	if (!preq_node) {
876 		mhwmp_dbg("could not allocate PREQ node");
877 		return;
878 	}
879 
880 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
881 	if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
882 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
883 		kfree(preq_node);
884 		if (printk_ratelimit())
885 			mhwmp_dbg("PREQ node queue full");
886 		return;
887 	}
888 
889 	spin_lock(&mpath->state_lock);
890 	if (mpath->flags & MESH_PATH_REQ_QUEUED) {
891 		spin_unlock(&mpath->state_lock);
892 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
893 		kfree(preq_node);
894 		return;
895 	}
896 
897 	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
898 	preq_node->flags = flags;
899 
900 	mpath->flags |= MESH_PATH_REQ_QUEUED;
901 	spin_unlock(&mpath->state_lock);
902 
903 	list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
904 	++ifmsh->preq_queue_len;
905 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
906 
907 	if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
908 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
909 
910 	else if (time_before(jiffies, ifmsh->last_preq)) {
911 		/* avoid long wait if did not send preqs for a long time
912 		 * and jiffies wrapped around
913 		 */
914 		ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
915 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
916 	} else
917 		mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
918 						min_preq_int_jiff(sdata));
919 }
920 
921 /**
922  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
923  *
924  * @sdata: local mesh subif
925  */
mesh_path_start_discovery(struct ieee80211_sub_if_data * sdata)926 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
927 {
928 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
929 	struct mesh_preq_queue *preq_node;
930 	struct mesh_path *mpath;
931 	u8 ttl, target_flags;
932 	const u8 *da;
933 	u32 lifetime;
934 
935 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
936 	if (!ifmsh->preq_queue_len ||
937 		time_before(jiffies, ifmsh->last_preq +
938 				min_preq_int_jiff(sdata))) {
939 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
940 		return;
941 	}
942 
943 	preq_node = list_first_entry(&ifmsh->preq_queue.list,
944 			struct mesh_preq_queue, list);
945 	list_del(&preq_node->list);
946 	--ifmsh->preq_queue_len;
947 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
948 
949 	rcu_read_lock();
950 	mpath = mesh_path_lookup(preq_node->dst, sdata);
951 	if (!mpath)
952 		goto enddiscovery;
953 
954 	spin_lock_bh(&mpath->state_lock);
955 	mpath->flags &= ~MESH_PATH_REQ_QUEUED;
956 	if (preq_node->flags & PREQ_Q_F_START) {
957 		if (mpath->flags & MESH_PATH_RESOLVING) {
958 			spin_unlock_bh(&mpath->state_lock);
959 			goto enddiscovery;
960 		} else {
961 			mpath->flags &= ~MESH_PATH_RESOLVED;
962 			mpath->flags |= MESH_PATH_RESOLVING;
963 			mpath->discovery_retries = 0;
964 			mpath->discovery_timeout = disc_timeout_jiff(sdata);
965 		}
966 	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
967 			mpath->flags & MESH_PATH_RESOLVED) {
968 		mpath->flags &= ~MESH_PATH_RESOLVING;
969 		spin_unlock_bh(&mpath->state_lock);
970 		goto enddiscovery;
971 	}
972 
973 	ifmsh->last_preq = jiffies;
974 
975 	if (time_after(jiffies, ifmsh->last_sn_update +
976 				net_traversal_jiffies(sdata)) ||
977 	    time_before(jiffies, ifmsh->last_sn_update)) {
978 		++ifmsh->sn;
979 		sdata->u.mesh.last_sn_update = jiffies;
980 	}
981 	lifetime = default_lifetime(sdata);
982 	ttl = sdata->u.mesh.mshcfg.element_ttl;
983 	if (ttl == 0) {
984 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
985 		spin_unlock_bh(&mpath->state_lock);
986 		goto enddiscovery;
987 	}
988 
989 	if (preq_node->flags & PREQ_Q_F_REFRESH)
990 		target_flags = MP_F_DO;
991 	else
992 		target_flags = MP_F_RF;
993 
994 	spin_unlock_bh(&mpath->state_lock);
995 	da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
996 	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
997 			cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
998 			cpu_to_le32(mpath->sn), da, 0,
999 			ttl, cpu_to_le32(lifetime), 0,
1000 			cpu_to_le32(ifmsh->preq_id++), sdata);
1001 	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1002 
1003 enddiscovery:
1004 	rcu_read_unlock();
1005 	kfree(preq_node);
1006 }
1007 
1008 /* mesh_nexthop_resolve - lookup next hop for given skb and start path
1009  * discovery if no forwarding information is found.
1010  *
1011  * @skb: 802.11 frame to be sent
1012  * @sdata: network subif the frame will be sent through
1013  *
1014  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1015  * skb is freeed here if no mpath could be allocated.
1016  */
mesh_nexthop_resolve(struct sk_buff * skb,struct ieee80211_sub_if_data * sdata)1017 int mesh_nexthop_resolve(struct sk_buff *skb,
1018 			 struct ieee80211_sub_if_data *sdata)
1019 {
1020 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1021 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1022 	struct mesh_path *mpath;
1023 	struct sk_buff *skb_to_free = NULL;
1024 	u8 *target_addr = hdr->addr3;
1025 	int err = 0;
1026 
1027 	rcu_read_lock();
1028 	err = mesh_nexthop_lookup(skb, sdata);
1029 	if (!err)
1030 		goto endlookup;
1031 
1032 	/* no nexthop found, start resolving */
1033 	mpath = mesh_path_lookup(target_addr, sdata);
1034 	if (!mpath) {
1035 		mesh_path_add(target_addr, sdata);
1036 		mpath = mesh_path_lookup(target_addr, sdata);
1037 		if (!mpath) {
1038 			mesh_path_discard_frame(skb, sdata);
1039 			err = -ENOSPC;
1040 			goto endlookup;
1041 		}
1042 	}
1043 
1044 	if (!(mpath->flags & MESH_PATH_RESOLVING))
1045 		mesh_queue_preq(mpath, PREQ_Q_F_START);
1046 
1047 	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1048 		skb_to_free = skb_dequeue(&mpath->frame_queue);
1049 
1050 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1051 	ieee80211_set_qos_hdr(sdata, skb);
1052 	skb_queue_tail(&mpath->frame_queue, skb);
1053 	err = -ENOENT;
1054 	if (skb_to_free)
1055 		mesh_path_discard_frame(skb_to_free, sdata);
1056 
1057 endlookup:
1058 	rcu_read_unlock();
1059 	return err;
1060 }
1061 /**
1062  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1063  * this function is considered "using" the associated mpath, so preempt a path
1064  * refresh if this mpath expires soon.
1065  *
1066  * @skb: 802.11 frame to be sent
1067  * @sdata: network subif the frame will be sent through
1068  *
1069  * Returns: 0 if the next hop was found. Nonzero otherwise.
1070  */
mesh_nexthop_lookup(struct sk_buff * skb,struct ieee80211_sub_if_data * sdata)1071 int mesh_nexthop_lookup(struct sk_buff *skb,
1072 			struct ieee80211_sub_if_data *sdata)
1073 {
1074 	struct mesh_path *mpath;
1075 	struct sta_info *next_hop;
1076 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1077 	u8 *target_addr = hdr->addr3;
1078 	int err = -ENOENT;
1079 
1080 	rcu_read_lock();
1081 	mpath = mesh_path_lookup(target_addr, sdata);
1082 
1083 	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1084 		goto endlookup;
1085 
1086 	if (time_after(jiffies,
1087 		       mpath->exp_time -
1088 		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1089 	    !compare_ether_addr(sdata->vif.addr, hdr->addr4) &&
1090 	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1091 	    !(mpath->flags & MESH_PATH_FIXED))
1092 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1093 
1094 	next_hop = rcu_dereference(mpath->next_hop);
1095 	if (next_hop) {
1096 		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1097 		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1098 		err = 0;
1099 	}
1100 
1101 endlookup:
1102 	rcu_read_unlock();
1103 	return err;
1104 }
1105 
mesh_path_timer(unsigned long data)1106 void mesh_path_timer(unsigned long data)
1107 {
1108 	struct mesh_path *mpath = (void *) data;
1109 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1110 	int ret;
1111 
1112 	if (sdata->local->quiescing)
1113 		return;
1114 
1115 	spin_lock_bh(&mpath->state_lock);
1116 	if (mpath->flags & MESH_PATH_RESOLVED ||
1117 			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1118 		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1119 		spin_unlock_bh(&mpath->state_lock);
1120 	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1121 		++mpath->discovery_retries;
1122 		mpath->discovery_timeout *= 2;
1123 		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1124 		spin_unlock_bh(&mpath->state_lock);
1125 		mesh_queue_preq(mpath, 0);
1126 	} else {
1127 		mpath->flags = 0;
1128 		mpath->exp_time = jiffies;
1129 		spin_unlock_bh(&mpath->state_lock);
1130 		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1131 			ret = mesh_path_send_to_gates(mpath);
1132 			if (ret)
1133 				mhwmp_dbg("no gate was reachable");
1134 		} else
1135 			mesh_path_flush_pending(mpath);
1136 	}
1137 }
1138 
1139 void
mesh_path_tx_root_frame(struct ieee80211_sub_if_data * sdata)1140 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1141 {
1142 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1143 	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1144 	u8 flags;
1145 
1146 	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1147 			? RANN_FLAG_IS_GATE : 0;
1148 	mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1149 			       cpu_to_le32(++ifmsh->sn),
1150 			       0, NULL, 0, broadcast_addr,
1151 			       0, sdata->u.mesh.mshcfg.element_ttl,
1152 			       cpu_to_le32(interval), 0, 0, sdata);
1153 }
1154