xref: /openbmc/linux/net/mac80211/mesh_hwmp.c (revision 15e47304)
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 #define TEST_FRAME_LEN	8192
17 #define MAX_METRIC	0xffffffff
18 #define ARITH_SHIFT	8
19 
20 #define MAX_PREQ_QUEUE_LEN	64
21 
22 /* Destination only */
23 #define MP_F_DO	0x1
24 /* Reply and forward */
25 #define MP_F_RF	0x2
26 /* Unknown Sequence Number */
27 #define MP_F_USN    0x01
28 /* Reason code Present */
29 #define MP_F_RCODE  0x02
30 
31 static void mesh_queue_preq(struct mesh_path *, u8);
32 
33 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
34 {
35 	if (ae)
36 		offset += 6;
37 	return get_unaligned_le32(preq_elem + offset);
38 }
39 
40 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
41 {
42 	if (ae)
43 		offset += 6;
44 	return get_unaligned_le16(preq_elem + offset);
45 }
46 
47 /* HWMP IE processing macros */
48 #define AE_F			(1<<6)
49 #define AE_F_SET(x)		(*x & AE_F)
50 #define PREQ_IE_FLAGS(x)	(*(x))
51 #define PREQ_IE_HOPCOUNT(x)	(*(x + 1))
52 #define PREQ_IE_TTL(x)		(*(x + 2))
53 #define PREQ_IE_PREQ_ID(x)	u32_field_get(x, 3, 0)
54 #define PREQ_IE_ORIG_ADDR(x)	(x + 7)
55 #define PREQ_IE_ORIG_SN(x)	u32_field_get(x, 13, 0)
56 #define PREQ_IE_LIFETIME(x)	u32_field_get(x, 17, AE_F_SET(x))
57 #define PREQ_IE_METRIC(x) 	u32_field_get(x, 21, AE_F_SET(x))
58 #define PREQ_IE_TARGET_F(x)	(*(AE_F_SET(x) ? x + 32 : x + 26))
59 #define PREQ_IE_TARGET_ADDR(x) 	(AE_F_SET(x) ? x + 33 : x + 27)
60 #define PREQ_IE_TARGET_SN(x) 	u32_field_get(x, 33, AE_F_SET(x))
61 
62 
63 #define PREP_IE_FLAGS(x)	PREQ_IE_FLAGS(x)
64 #define PREP_IE_HOPCOUNT(x)	PREQ_IE_HOPCOUNT(x)
65 #define PREP_IE_TTL(x)		PREQ_IE_TTL(x)
66 #define PREP_IE_ORIG_ADDR(x)	(AE_F_SET(x) ? x + 27 : x + 21)
67 #define PREP_IE_ORIG_SN(x)	u32_field_get(x, 27, AE_F_SET(x))
68 #define PREP_IE_LIFETIME(x)	u32_field_get(x, 13, AE_F_SET(x))
69 #define PREP_IE_METRIC(x)	u32_field_get(x, 17, AE_F_SET(x))
70 #define PREP_IE_TARGET_ADDR(x)	(x + 3)
71 #define PREP_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
72 
73 #define PERR_IE_TTL(x)		(*(x))
74 #define PERR_IE_TARGET_FLAGS(x)	(*(x + 2))
75 #define PERR_IE_TARGET_ADDR(x)	(x + 3)
76 #define PERR_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
77 #define PERR_IE_TARGET_RCODE(x)	u16_field_get(x, 13, 0)
78 
79 #define MSEC_TO_TU(x) (x*1000/1024)
80 #define SN_GT(x, y) ((s32)(y - x) < 0)
81 #define SN_LT(x, y) ((s32)(x - y) < 0)
82 
83 #define net_traversal_jiffies(s) \
84 	msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
85 #define default_lifetime(s) \
86 	MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
87 #define min_preq_int_jiff(s) \
88 	(msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
89 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
90 #define disc_timeout_jiff(s) \
91 	msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
92 #define root_path_confirmation_jiffies(s) \
93 	msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
94 
95 enum mpath_frame_type {
96 	MPATH_PREQ = 0,
97 	MPATH_PREP,
98 	MPATH_PERR,
99 	MPATH_RANN
100 };
101 
102 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
103 
104 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
105 		u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
106 		__le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
107 		__le32 lifetime, __le32 metric, __le32 preq_id,
108 		struct ieee80211_sub_if_data *sdata)
109 {
110 	struct ieee80211_local *local = sdata->local;
111 	struct sk_buff *skb;
112 	struct ieee80211_mgmt *mgmt;
113 	u8 *pos, ie_len;
114 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
115 		      sizeof(mgmt->u.action.u.mesh_action);
116 
117 	skb = dev_alloc_skb(local->tx_headroom +
118 			    hdr_len +
119 			    2 + 37); /* max HWMP IE */
120 	if (!skb)
121 		return -1;
122 	skb_reserve(skb, local->tx_headroom);
123 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
124 	memset(mgmt, 0, hdr_len);
125 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
126 					  IEEE80211_STYPE_ACTION);
127 
128 	memcpy(mgmt->da, da, ETH_ALEN);
129 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
130 	/* BSSID == SA */
131 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
132 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
133 	mgmt->u.action.u.mesh_action.action_code =
134 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
135 
136 	switch (action) {
137 	case MPATH_PREQ:
138 		mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
139 		ie_len = 37;
140 		pos = skb_put(skb, 2 + ie_len);
141 		*pos++ = WLAN_EID_PREQ;
142 		break;
143 	case MPATH_PREP:
144 		mhwmp_dbg(sdata, "sending PREP to %pM\n", target);
145 		ie_len = 31;
146 		pos = skb_put(skb, 2 + ie_len);
147 		*pos++ = WLAN_EID_PREP;
148 		break;
149 	case MPATH_RANN:
150 		mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
151 		ie_len = sizeof(struct ieee80211_rann_ie);
152 		pos = skb_put(skb, 2 + ie_len);
153 		*pos++ = WLAN_EID_RANN;
154 		break;
155 	default:
156 		kfree_skb(skb);
157 		return -ENOTSUPP;
158 		break;
159 	}
160 	*pos++ = ie_len;
161 	*pos++ = flags;
162 	*pos++ = hop_count;
163 	*pos++ = ttl;
164 	if (action == MPATH_PREP) {
165 		memcpy(pos, target, ETH_ALEN);
166 		pos += ETH_ALEN;
167 		memcpy(pos, &target_sn, 4);
168 		pos += 4;
169 	} else {
170 		if (action == MPATH_PREQ) {
171 			memcpy(pos, &preq_id, 4);
172 			pos += 4;
173 		}
174 		memcpy(pos, orig_addr, ETH_ALEN);
175 		pos += ETH_ALEN;
176 		memcpy(pos, &orig_sn, 4);
177 		pos += 4;
178 	}
179 	memcpy(pos, &lifetime, 4);	/* interval for RANN */
180 	pos += 4;
181 	memcpy(pos, &metric, 4);
182 	pos += 4;
183 	if (action == MPATH_PREQ) {
184 		*pos++ = 1; /* destination count */
185 		*pos++ = target_flags;
186 		memcpy(pos, target, ETH_ALEN);
187 		pos += ETH_ALEN;
188 		memcpy(pos, &target_sn, 4);
189 		pos += 4;
190 	} else if (action == MPATH_PREP) {
191 		memcpy(pos, orig_addr, ETH_ALEN);
192 		pos += ETH_ALEN;
193 		memcpy(pos, &orig_sn, 4);
194 		pos += 4;
195 	}
196 
197 	ieee80211_tx_skb(sdata, skb);
198 	return 0;
199 }
200 
201 
202 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
203  *  headroom in case the frame is encrypted. */
204 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
205 		struct sk_buff *skb)
206 {
207 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
208 
209 	skb_set_mac_header(skb, 0);
210 	skb_set_network_header(skb, 0);
211 	skb_set_transport_header(skb, 0);
212 
213 	/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
214 	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
215 	skb->priority = 7;
216 
217 	info->control.vif = &sdata->vif;
218 	ieee80211_set_qos_hdr(sdata, skb);
219 }
220 
221 /**
222  * mesh_send_path error - Sends a PERR mesh management frame
223  *
224  * @target: broken destination
225  * @target_sn: SN of the broken destination
226  * @target_rcode: reason code for this PERR
227  * @ra: node this frame is addressed to
228  *
229  * Note: This function may be called with driver locks taken that the driver
230  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
231  * frame directly but add it to the pending queue instead.
232  */
233 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
234 		       __le16 target_rcode, const u8 *ra,
235 		       struct ieee80211_sub_if_data *sdata)
236 {
237 	struct ieee80211_local *local = sdata->local;
238 	struct sk_buff *skb;
239 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
240 	struct ieee80211_mgmt *mgmt;
241 	u8 *pos, ie_len;
242 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
243 		      sizeof(mgmt->u.action.u.mesh_action);
244 
245 	if (time_before(jiffies, ifmsh->next_perr))
246 		return -EAGAIN;
247 
248 	skb = dev_alloc_skb(local->tx_headroom +
249 			    hdr_len +
250 			    2 + 15 /* PERR IE */);
251 	if (!skb)
252 		return -1;
253 	skb_reserve(skb, local->tx_headroom);
254 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
255 	memset(mgmt, 0, hdr_len);
256 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
257 					  IEEE80211_STYPE_ACTION);
258 
259 	memcpy(mgmt->da, ra, ETH_ALEN);
260 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
261 	/* BSSID == SA */
262 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
263 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
264 	mgmt->u.action.u.mesh_action.action_code =
265 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
266 	ie_len = 15;
267 	pos = skb_put(skb, 2 + ie_len);
268 	*pos++ = WLAN_EID_PERR;
269 	*pos++ = ie_len;
270 	/* ttl */
271 	*pos++ = ttl;
272 	/* number of destinations */
273 	*pos++ = 1;
274 	/*
275 	 * flags bit, bit 1 is unset if we know the sequence number and
276 	 * bit 2 is set if we have a reason code
277 	 */
278 	*pos = 0;
279 	if (!target_sn)
280 		*pos |= MP_F_USN;
281 	if (target_rcode)
282 		*pos |= MP_F_RCODE;
283 	pos++;
284 	memcpy(pos, target, ETH_ALEN);
285 	pos += ETH_ALEN;
286 	memcpy(pos, &target_sn, 4);
287 	pos += 4;
288 	memcpy(pos, &target_rcode, 2);
289 
290 	/* see note in function header */
291 	prepare_frame_for_deferred_tx(sdata, skb);
292 	ifmsh->next_perr = TU_TO_EXP_TIME(
293 				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
294 	ieee80211_add_pending_skb(local, skb);
295 	return 0;
296 }
297 
298 void ieee80211s_update_metric(struct ieee80211_local *local,
299 		struct sta_info *sta, struct sk_buff *skb)
300 {
301 	struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
302 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
303 	int failed;
304 
305 	if (!ieee80211_is_data(hdr->frame_control))
306 		return;
307 
308 	failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
309 
310 	/* moving average, scaled to 100 */
311 	sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
312 	if (sta->fail_avg > 95)
313 		mesh_plink_broken(sta);
314 }
315 
316 static u32 airtime_link_metric_get(struct ieee80211_local *local,
317 				   struct sta_info *sta)
318 {
319 	struct rate_info rinfo;
320 	/* This should be adjusted for each device */
321 	int device_constant = 1 << ARITH_SHIFT;
322 	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
323 	int s_unit = 1 << ARITH_SHIFT;
324 	int rate, err;
325 	u32 tx_time, estimated_retx;
326 	u64 result;
327 
328 	if (sta->fail_avg >= 100)
329 		return MAX_METRIC;
330 
331 	sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
332 	rate = cfg80211_calculate_bitrate(&rinfo);
333 	if (WARN_ON(!rate))
334 		return MAX_METRIC;
335 
336 	err = (sta->fail_avg << ARITH_SHIFT) / 100;
337 
338 	/* bitrate is in units of 100 Kbps, while we need rate in units of
339 	 * 1Mbps. This will be corrected on tx_time computation.
340 	 */
341 	tx_time = (device_constant + 10 * test_frame_len / rate);
342 	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
343 	result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
344 	return (u32)result;
345 }
346 
347 /**
348  * hwmp_route_info_get - Update routing info to originator and transmitter
349  *
350  * @sdata: local mesh subif
351  * @mgmt: mesh management frame
352  * @hwmp_ie: hwmp information element (PREP or PREQ)
353  *
354  * This function updates the path routing information to the originator and the
355  * transmitter of a HWMP PREQ or PREP frame.
356  *
357  * Returns: metric to frame originator or 0 if the frame should not be further
358  * processed
359  *
360  * Notes: this function is the only place (besides user-provided info) where
361  * path routing information is updated.
362  */
363 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
364 			    struct ieee80211_mgmt *mgmt,
365 			    u8 *hwmp_ie, enum mpath_frame_type action)
366 {
367 	struct ieee80211_local *local = sdata->local;
368 	struct mesh_path *mpath;
369 	struct sta_info *sta;
370 	bool fresh_info;
371 	u8 *orig_addr, *ta;
372 	u32 orig_sn, orig_metric;
373 	unsigned long orig_lifetime, exp_time;
374 	u32 last_hop_metric, new_metric;
375 	bool process = true;
376 
377 	rcu_read_lock();
378 	sta = sta_info_get(sdata, mgmt->sa);
379 	if (!sta) {
380 		rcu_read_unlock();
381 		return 0;
382 	}
383 
384 	last_hop_metric = airtime_link_metric_get(local, sta);
385 	/* Update and check originator routing info */
386 	fresh_info = true;
387 
388 	switch (action) {
389 	case MPATH_PREQ:
390 		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
391 		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
392 		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
393 		orig_metric = PREQ_IE_METRIC(hwmp_ie);
394 		break;
395 	case MPATH_PREP:
396 		/* Originator here refers to the MP that was the target in the
397 		 * Path Request. We divert from the nomenclature in the draft
398 		 * so that we can easily use a single function to gather path
399 		 * information from both PREQ and PREP frames.
400 		 */
401 		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
402 		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
403 		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
404 		orig_metric = PREP_IE_METRIC(hwmp_ie);
405 		break;
406 	default:
407 		rcu_read_unlock();
408 		return 0;
409 	}
410 	new_metric = orig_metric + last_hop_metric;
411 	if (new_metric < orig_metric)
412 		new_metric = MAX_METRIC;
413 	exp_time = TU_TO_EXP_TIME(orig_lifetime);
414 
415 	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
416 		/* This MP is the originator, we are not interested in this
417 		 * frame, except for updating transmitter's path info.
418 		 */
419 		process = false;
420 		fresh_info = false;
421 	} else {
422 		mpath = mesh_path_lookup(orig_addr, sdata);
423 		if (mpath) {
424 			spin_lock_bh(&mpath->state_lock);
425 			if (mpath->flags & MESH_PATH_FIXED)
426 				fresh_info = false;
427 			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
428 			    (mpath->flags & MESH_PATH_SN_VALID)) {
429 				if (SN_GT(mpath->sn, orig_sn) ||
430 				    (mpath->sn == orig_sn &&
431 				     new_metric >= mpath->metric)) {
432 					process = false;
433 					fresh_info = false;
434 				}
435 			}
436 		} else {
437 			mesh_path_add(orig_addr, sdata);
438 			mpath = mesh_path_lookup(orig_addr, sdata);
439 			if (!mpath) {
440 				rcu_read_unlock();
441 				return 0;
442 			}
443 			spin_lock_bh(&mpath->state_lock);
444 		}
445 
446 		if (fresh_info) {
447 			mesh_path_assign_nexthop(mpath, sta);
448 			mpath->flags |= MESH_PATH_SN_VALID;
449 			mpath->metric = new_metric;
450 			mpath->sn = orig_sn;
451 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
452 					  ?  mpath->exp_time : exp_time;
453 			mesh_path_activate(mpath);
454 			spin_unlock_bh(&mpath->state_lock);
455 			mesh_path_tx_pending(mpath);
456 			/* draft says preq_id should be saved to, but there does
457 			 * not seem to be any use for it, skipping by now
458 			 */
459 		} else
460 			spin_unlock_bh(&mpath->state_lock);
461 	}
462 
463 	/* Update and check transmitter routing info */
464 	ta = mgmt->sa;
465 	if (ether_addr_equal(orig_addr, ta))
466 		fresh_info = false;
467 	else {
468 		fresh_info = true;
469 
470 		mpath = mesh_path_lookup(ta, sdata);
471 		if (mpath) {
472 			spin_lock_bh(&mpath->state_lock);
473 			if ((mpath->flags & MESH_PATH_FIXED) ||
474 				((mpath->flags & MESH_PATH_ACTIVE) &&
475 					(last_hop_metric > mpath->metric)))
476 				fresh_info = false;
477 		} else {
478 			mesh_path_add(ta, sdata);
479 			mpath = mesh_path_lookup(ta, sdata);
480 			if (!mpath) {
481 				rcu_read_unlock();
482 				return 0;
483 			}
484 			spin_lock_bh(&mpath->state_lock);
485 		}
486 
487 		if (fresh_info) {
488 			mesh_path_assign_nexthop(mpath, sta);
489 			mpath->metric = last_hop_metric;
490 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
491 					  ?  mpath->exp_time : exp_time;
492 			mesh_path_activate(mpath);
493 			spin_unlock_bh(&mpath->state_lock);
494 			mesh_path_tx_pending(mpath);
495 		} else
496 			spin_unlock_bh(&mpath->state_lock);
497 	}
498 
499 	rcu_read_unlock();
500 
501 	return process ? new_metric : 0;
502 }
503 
504 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
505 				    struct ieee80211_mgmt *mgmt,
506 				    u8 *preq_elem, u32 metric)
507 {
508 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
509 	struct mesh_path *mpath = NULL;
510 	u8 *target_addr, *orig_addr;
511 	const u8 *da;
512 	u8 target_flags, ttl, flags;
513 	u32 orig_sn, target_sn, lifetime, orig_metric;
514 	bool reply = false;
515 	bool forward = true;
516 	bool root_is_gate;
517 
518 	/* Update target SN, if present */
519 	target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
520 	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
521 	target_sn = PREQ_IE_TARGET_SN(preq_elem);
522 	orig_sn = PREQ_IE_ORIG_SN(preq_elem);
523 	target_flags = PREQ_IE_TARGET_F(preq_elem);
524 	orig_metric = metric;
525 	/* Proactive PREQ gate announcements */
526 	flags = PREQ_IE_FLAGS(preq_elem);
527 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
528 
529 	mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
530 
531 	if (ether_addr_equal(target_addr, sdata->vif.addr)) {
532 		mhwmp_dbg(sdata, "PREQ is for us\n");
533 		forward = false;
534 		reply = true;
535 		metric = 0;
536 		if (time_after(jiffies, ifmsh->last_sn_update +
537 					net_traversal_jiffies(sdata)) ||
538 		    time_before(jiffies, ifmsh->last_sn_update)) {
539 			target_sn = ++ifmsh->sn;
540 			ifmsh->last_sn_update = jiffies;
541 		}
542 	} else if (is_broadcast_ether_addr(target_addr) &&
543 		   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
544 		rcu_read_lock();
545 		mpath = mesh_path_lookup(orig_addr, sdata);
546 		if (mpath) {
547 			if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
548 				reply = true;
549 				target_addr = sdata->vif.addr;
550 				target_sn = ++ifmsh->sn;
551 				metric = 0;
552 				ifmsh->last_sn_update = jiffies;
553 			}
554 			if (root_is_gate)
555 				mesh_path_add_gate(mpath);
556 		}
557 		rcu_read_unlock();
558 	} else {
559 		rcu_read_lock();
560 		mpath = mesh_path_lookup(target_addr, sdata);
561 		if (mpath) {
562 			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
563 					SN_LT(mpath->sn, target_sn)) {
564 				mpath->sn = target_sn;
565 				mpath->flags |= MESH_PATH_SN_VALID;
566 			} else if ((!(target_flags & MP_F_DO)) &&
567 					(mpath->flags & MESH_PATH_ACTIVE)) {
568 				reply = true;
569 				metric = mpath->metric;
570 				target_sn = mpath->sn;
571 				if (target_flags & MP_F_RF)
572 					target_flags |= MP_F_DO;
573 				else
574 					forward = false;
575 			}
576 		}
577 		rcu_read_unlock();
578 	}
579 
580 	if (reply) {
581 		lifetime = PREQ_IE_LIFETIME(preq_elem);
582 		ttl = ifmsh->mshcfg.element_ttl;
583 		if (ttl != 0) {
584 			mhwmp_dbg(sdata, "replying to the PREQ\n");
585 			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
586 				cpu_to_le32(orig_sn), 0, target_addr,
587 				cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
588 				cpu_to_le32(lifetime), cpu_to_le32(metric),
589 				0, sdata);
590 		} else {
591 			ifmsh->mshstats.dropped_frames_ttl++;
592 		}
593 	}
594 
595 	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
596 		u32 preq_id;
597 		u8 hopcount;
598 
599 		ttl = PREQ_IE_TTL(preq_elem);
600 		lifetime = PREQ_IE_LIFETIME(preq_elem);
601 		if (ttl <= 1) {
602 			ifmsh->mshstats.dropped_frames_ttl++;
603 			return;
604 		}
605 		mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
606 		--ttl;
607 		preq_id = PREQ_IE_PREQ_ID(preq_elem);
608 		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
609 		da = (mpath && mpath->is_root) ?
610 			mpath->rann_snd_addr : broadcast_addr;
611 
612 		if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
613 			target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
614 			target_sn = PREQ_IE_TARGET_SN(preq_elem);
615 			metric = orig_metric;
616 		}
617 
618 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
619 				cpu_to_le32(orig_sn), target_flags, target_addr,
620 				cpu_to_le32(target_sn), da,
621 				hopcount, ttl, cpu_to_le32(lifetime),
622 				cpu_to_le32(metric), cpu_to_le32(preq_id),
623 				sdata);
624 		if (!is_multicast_ether_addr(da))
625 			ifmsh->mshstats.fwded_unicast++;
626 		else
627 			ifmsh->mshstats.fwded_mcast++;
628 		ifmsh->mshstats.fwded_frames++;
629 	}
630 }
631 
632 
633 static inline struct sta_info *
634 next_hop_deref_protected(struct mesh_path *mpath)
635 {
636 	return rcu_dereference_protected(mpath->next_hop,
637 					 lockdep_is_held(&mpath->state_lock));
638 }
639 
640 
641 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
642 				    struct ieee80211_mgmt *mgmt,
643 				    u8 *prep_elem, u32 metric)
644 {
645 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
646 	struct mesh_path *mpath;
647 	u8 *target_addr, *orig_addr;
648 	u8 ttl, hopcount, flags;
649 	u8 next_hop[ETH_ALEN];
650 	u32 target_sn, orig_sn, lifetime;
651 
652 	mhwmp_dbg(sdata, "received PREP from %pM\n",
653 		  PREP_IE_ORIG_ADDR(prep_elem));
654 
655 	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
656 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
657 		/* destination, no forwarding required */
658 		return;
659 
660 	if (!ifmsh->mshcfg.dot11MeshForwarding)
661 		return;
662 
663 	ttl = PREP_IE_TTL(prep_elem);
664 	if (ttl <= 1) {
665 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
666 		return;
667 	}
668 
669 	rcu_read_lock();
670 	mpath = mesh_path_lookup(orig_addr, sdata);
671 	if (mpath)
672 		spin_lock_bh(&mpath->state_lock);
673 	else
674 		goto fail;
675 	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
676 		spin_unlock_bh(&mpath->state_lock);
677 		goto fail;
678 	}
679 	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
680 	spin_unlock_bh(&mpath->state_lock);
681 	--ttl;
682 	flags = PREP_IE_FLAGS(prep_elem);
683 	lifetime = PREP_IE_LIFETIME(prep_elem);
684 	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
685 	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
686 	target_sn = PREP_IE_TARGET_SN(prep_elem);
687 	orig_sn = PREP_IE_ORIG_SN(prep_elem);
688 
689 	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
690 		cpu_to_le32(orig_sn), 0, target_addr,
691 		cpu_to_le32(target_sn), next_hop, hopcount,
692 		ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
693 		0, sdata);
694 	rcu_read_unlock();
695 
696 	sdata->u.mesh.mshstats.fwded_unicast++;
697 	sdata->u.mesh.mshstats.fwded_frames++;
698 	return;
699 
700 fail:
701 	rcu_read_unlock();
702 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
703 }
704 
705 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
706 			     struct ieee80211_mgmt *mgmt, u8 *perr_elem)
707 {
708 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
709 	struct mesh_path *mpath;
710 	u8 ttl;
711 	u8 *ta, *target_addr;
712 	u32 target_sn;
713 	u16 target_rcode;
714 
715 	ta = mgmt->sa;
716 	ttl = PERR_IE_TTL(perr_elem);
717 	if (ttl <= 1) {
718 		ifmsh->mshstats.dropped_frames_ttl++;
719 		return;
720 	}
721 	ttl--;
722 	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
723 	target_sn = PERR_IE_TARGET_SN(perr_elem);
724 	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
725 
726 	rcu_read_lock();
727 	mpath = mesh_path_lookup(target_addr, sdata);
728 	if (mpath) {
729 		struct sta_info *sta;
730 
731 		spin_lock_bh(&mpath->state_lock);
732 		sta = next_hop_deref_protected(mpath);
733 		if (mpath->flags & MESH_PATH_ACTIVE &&
734 		    ether_addr_equal(ta, sta->sta.addr) &&
735 		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
736 		    SN_GT(target_sn, mpath->sn))) {
737 			mpath->flags &= ~MESH_PATH_ACTIVE;
738 			mpath->sn = target_sn;
739 			spin_unlock_bh(&mpath->state_lock);
740 			if (!ifmsh->mshcfg.dot11MeshForwarding)
741 				goto endperr;
742 			mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
743 					   cpu_to_le16(target_rcode),
744 					   broadcast_addr, sdata);
745 		} else
746 			spin_unlock_bh(&mpath->state_lock);
747 	}
748 endperr:
749 	rcu_read_unlock();
750 }
751 
752 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
753 				struct ieee80211_mgmt *mgmt,
754 				struct ieee80211_rann_ie *rann)
755 {
756 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
757 	struct ieee80211_local *local = sdata->local;
758 	struct sta_info *sta;
759 	struct mesh_path *mpath;
760 	u8 ttl, flags, hopcount;
761 	u8 *orig_addr;
762 	u32 orig_sn, metric, metric_txsta, interval;
763 	bool root_is_gate;
764 
765 	ttl = rann->rann_ttl;
766 	flags = rann->rann_flags;
767 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
768 	orig_addr = rann->rann_addr;
769 	orig_sn = le32_to_cpu(rann->rann_seq);
770 	interval = le32_to_cpu(rann->rann_interval);
771 	hopcount = rann->rann_hopcount;
772 	hopcount++;
773 	metric = le32_to_cpu(rann->rann_metric);
774 
775 	/*  Ignore our own RANNs */
776 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
777 		return;
778 
779 	mhwmp_dbg(sdata,
780 		  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
781 		  orig_addr, mgmt->sa, root_is_gate);
782 
783 	rcu_read_lock();
784 	sta = sta_info_get(sdata, mgmt->sa);
785 	if (!sta) {
786 		rcu_read_unlock();
787 		return;
788 	}
789 
790 	metric_txsta = airtime_link_metric_get(local, sta);
791 
792 	mpath = mesh_path_lookup(orig_addr, sdata);
793 	if (!mpath) {
794 		mesh_path_add(orig_addr, sdata);
795 		mpath = mesh_path_lookup(orig_addr, sdata);
796 		if (!mpath) {
797 			rcu_read_unlock();
798 			sdata->u.mesh.mshstats.dropped_frames_no_route++;
799 			return;
800 		}
801 	}
802 
803 	if (!(SN_LT(mpath->sn, orig_sn)) &&
804 	    !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
805 		rcu_read_unlock();
806 		return;
807 	}
808 
809 	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
810 	     (time_after(jiffies, mpath->last_preq_to_root +
811 				  root_path_confirmation_jiffies(sdata)) ||
812 	     time_before(jiffies, mpath->last_preq_to_root))) &&
813 	     !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
814 		mhwmp_dbg(sdata,
815 			  "time to refresh root mpath %pM\n",
816 			  orig_addr);
817 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
818 		mpath->last_preq_to_root = jiffies;
819 	}
820 
821 	mpath->sn = orig_sn;
822 	mpath->rann_metric = metric + metric_txsta;
823 	mpath->is_root = true;
824 	/* Recording RANNs sender address to send individually
825 	 * addressed PREQs destined for root mesh STA */
826 	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
827 
828 	if (root_is_gate)
829 		mesh_path_add_gate(mpath);
830 
831 	if (ttl <= 1) {
832 		ifmsh->mshstats.dropped_frames_ttl++;
833 		rcu_read_unlock();
834 		return;
835 	}
836 	ttl--;
837 
838 	if (ifmsh->mshcfg.dot11MeshForwarding) {
839 		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
840 				       cpu_to_le32(orig_sn),
841 				       0, NULL, 0, broadcast_addr,
842 				       hopcount, ttl, cpu_to_le32(interval),
843 				       cpu_to_le32(metric + metric_txsta),
844 				       0, sdata);
845 	}
846 
847 	rcu_read_unlock();
848 }
849 
850 
851 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
852 			    struct ieee80211_mgmt *mgmt,
853 			    size_t len)
854 {
855 	struct ieee802_11_elems elems;
856 	size_t baselen;
857 	u32 last_hop_metric;
858 	struct sta_info *sta;
859 
860 	/* need action_code */
861 	if (len < IEEE80211_MIN_ACTION_SIZE + 1)
862 		return;
863 
864 	rcu_read_lock();
865 	sta = sta_info_get(sdata, mgmt->sa);
866 	if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
867 		rcu_read_unlock();
868 		return;
869 	}
870 	rcu_read_unlock();
871 
872 	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
873 	ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
874 			len - baselen, &elems);
875 
876 	if (elems.preq) {
877 		if (elems.preq_len != 37)
878 			/* Right now we support just 1 destination and no AE */
879 			return;
880 		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
881 						      MPATH_PREQ);
882 		if (last_hop_metric)
883 			hwmp_preq_frame_process(sdata, mgmt, elems.preq,
884 						last_hop_metric);
885 	}
886 	if (elems.prep) {
887 		if (elems.prep_len != 31)
888 			/* Right now we support no AE */
889 			return;
890 		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
891 						      MPATH_PREP);
892 		if (last_hop_metric)
893 			hwmp_prep_frame_process(sdata, mgmt, elems.prep,
894 						last_hop_metric);
895 	}
896 	if (elems.perr) {
897 		if (elems.perr_len != 15)
898 			/* Right now we support only one destination per PERR */
899 			return;
900 		hwmp_perr_frame_process(sdata, mgmt, elems.perr);
901 	}
902 	if (elems.rann)
903 		hwmp_rann_frame_process(sdata, mgmt, elems.rann);
904 }
905 
906 /**
907  * mesh_queue_preq - queue a PREQ to a given destination
908  *
909  * @mpath: mesh path to discover
910  * @flags: special attributes of the PREQ to be sent
911  *
912  * Locking: the function must be called from within a rcu read lock block.
913  *
914  */
915 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
916 {
917 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
918 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
919 	struct mesh_preq_queue *preq_node;
920 
921 	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
922 	if (!preq_node) {
923 		mhwmp_dbg(sdata, "could not allocate PREQ node\n");
924 		return;
925 	}
926 
927 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
928 	if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
929 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
930 		kfree(preq_node);
931 		if (printk_ratelimit())
932 			mhwmp_dbg(sdata, "PREQ node queue full\n");
933 		return;
934 	}
935 
936 	spin_lock(&mpath->state_lock);
937 	if (mpath->flags & MESH_PATH_REQ_QUEUED) {
938 		spin_unlock(&mpath->state_lock);
939 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
940 		kfree(preq_node);
941 		return;
942 	}
943 
944 	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
945 	preq_node->flags = flags;
946 
947 	mpath->flags |= MESH_PATH_REQ_QUEUED;
948 	spin_unlock(&mpath->state_lock);
949 
950 	list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
951 	++ifmsh->preq_queue_len;
952 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
953 
954 	if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
955 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
956 
957 	else if (time_before(jiffies, ifmsh->last_preq)) {
958 		/* avoid long wait if did not send preqs for a long time
959 		 * and jiffies wrapped around
960 		 */
961 		ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
962 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
963 	} else
964 		mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
965 						min_preq_int_jiff(sdata));
966 }
967 
968 /**
969  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
970  *
971  * @sdata: local mesh subif
972  */
973 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
974 {
975 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
976 	struct mesh_preq_queue *preq_node;
977 	struct mesh_path *mpath;
978 	u8 ttl, target_flags;
979 	const u8 *da;
980 	u32 lifetime;
981 
982 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
983 	if (!ifmsh->preq_queue_len ||
984 		time_before(jiffies, ifmsh->last_preq +
985 				min_preq_int_jiff(sdata))) {
986 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
987 		return;
988 	}
989 
990 	preq_node = list_first_entry(&ifmsh->preq_queue.list,
991 			struct mesh_preq_queue, list);
992 	list_del(&preq_node->list);
993 	--ifmsh->preq_queue_len;
994 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
995 
996 	rcu_read_lock();
997 	mpath = mesh_path_lookup(preq_node->dst, sdata);
998 	if (!mpath)
999 		goto enddiscovery;
1000 
1001 	spin_lock_bh(&mpath->state_lock);
1002 	mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1003 	if (preq_node->flags & PREQ_Q_F_START) {
1004 		if (mpath->flags & MESH_PATH_RESOLVING) {
1005 			spin_unlock_bh(&mpath->state_lock);
1006 			goto enddiscovery;
1007 		} else {
1008 			mpath->flags &= ~MESH_PATH_RESOLVED;
1009 			mpath->flags |= MESH_PATH_RESOLVING;
1010 			mpath->discovery_retries = 0;
1011 			mpath->discovery_timeout = disc_timeout_jiff(sdata);
1012 		}
1013 	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1014 			mpath->flags & MESH_PATH_RESOLVED) {
1015 		mpath->flags &= ~MESH_PATH_RESOLVING;
1016 		spin_unlock_bh(&mpath->state_lock);
1017 		goto enddiscovery;
1018 	}
1019 
1020 	ifmsh->last_preq = jiffies;
1021 
1022 	if (time_after(jiffies, ifmsh->last_sn_update +
1023 				net_traversal_jiffies(sdata)) ||
1024 	    time_before(jiffies, ifmsh->last_sn_update)) {
1025 		++ifmsh->sn;
1026 		sdata->u.mesh.last_sn_update = jiffies;
1027 	}
1028 	lifetime = default_lifetime(sdata);
1029 	ttl = sdata->u.mesh.mshcfg.element_ttl;
1030 	if (ttl == 0) {
1031 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
1032 		spin_unlock_bh(&mpath->state_lock);
1033 		goto enddiscovery;
1034 	}
1035 
1036 	if (preq_node->flags & PREQ_Q_F_REFRESH)
1037 		target_flags = MP_F_DO;
1038 	else
1039 		target_flags = MP_F_RF;
1040 
1041 	spin_unlock_bh(&mpath->state_lock);
1042 	da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1043 	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1044 			cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1045 			cpu_to_le32(mpath->sn), da, 0,
1046 			ttl, cpu_to_le32(lifetime), 0,
1047 			cpu_to_le32(ifmsh->preq_id++), sdata);
1048 	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1049 
1050 enddiscovery:
1051 	rcu_read_unlock();
1052 	kfree(preq_node);
1053 }
1054 
1055 /**
1056  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1057  *
1058  * @skb: 802.11 frame to be sent
1059  * @sdata: network subif the frame will be sent through
1060  *
1061  * Lookup next hop for given skb and start path discovery if no
1062  * forwarding information is found.
1063  *
1064  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1065  * skb is freeed here if no mpath could be allocated.
1066  */
1067 int mesh_nexthop_resolve(struct sk_buff *skb,
1068 			 struct ieee80211_sub_if_data *sdata)
1069 {
1070 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1071 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1072 	struct mesh_path *mpath;
1073 	struct sk_buff *skb_to_free = NULL;
1074 	u8 *target_addr = hdr->addr3;
1075 	int err = 0;
1076 
1077 	rcu_read_lock();
1078 	err = mesh_nexthop_lookup(skb, sdata);
1079 	if (!err)
1080 		goto endlookup;
1081 
1082 	/* no nexthop found, start resolving */
1083 	mpath = mesh_path_lookup(target_addr, sdata);
1084 	if (!mpath) {
1085 		mesh_path_add(target_addr, sdata);
1086 		mpath = mesh_path_lookup(target_addr, sdata);
1087 		if (!mpath) {
1088 			mesh_path_discard_frame(skb, sdata);
1089 			err = -ENOSPC;
1090 			goto endlookup;
1091 		}
1092 	}
1093 
1094 	if (!(mpath->flags & MESH_PATH_RESOLVING))
1095 		mesh_queue_preq(mpath, PREQ_Q_F_START);
1096 
1097 	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1098 		skb_to_free = skb_dequeue(&mpath->frame_queue);
1099 
1100 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1101 	ieee80211_set_qos_hdr(sdata, skb);
1102 	skb_queue_tail(&mpath->frame_queue, skb);
1103 	err = -ENOENT;
1104 	if (skb_to_free)
1105 		mesh_path_discard_frame(skb_to_free, sdata);
1106 
1107 endlookup:
1108 	rcu_read_unlock();
1109 	return err;
1110 }
1111 /**
1112  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1113  * this function is considered "using" the associated mpath, so preempt a path
1114  * refresh if this mpath expires soon.
1115  *
1116  * @skb: 802.11 frame to be sent
1117  * @sdata: network subif the frame will be sent through
1118  *
1119  * Returns: 0 if the next hop was found. Nonzero otherwise.
1120  */
1121 int mesh_nexthop_lookup(struct sk_buff *skb,
1122 			struct ieee80211_sub_if_data *sdata)
1123 {
1124 	struct mesh_path *mpath;
1125 	struct sta_info *next_hop;
1126 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1127 	u8 *target_addr = hdr->addr3;
1128 	int err = -ENOENT;
1129 
1130 	rcu_read_lock();
1131 	mpath = mesh_path_lookup(target_addr, sdata);
1132 
1133 	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1134 		goto endlookup;
1135 
1136 	if (time_after(jiffies,
1137 		       mpath->exp_time -
1138 		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1139 	    ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1140 	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1141 	    !(mpath->flags & MESH_PATH_FIXED))
1142 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1143 
1144 	next_hop = rcu_dereference(mpath->next_hop);
1145 	if (next_hop) {
1146 		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1147 		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1148 		err = 0;
1149 	}
1150 
1151 endlookup:
1152 	rcu_read_unlock();
1153 	return err;
1154 }
1155 
1156 void mesh_path_timer(unsigned long data)
1157 {
1158 	struct mesh_path *mpath = (void *) data;
1159 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1160 	int ret;
1161 
1162 	if (sdata->local->quiescing)
1163 		return;
1164 
1165 	spin_lock_bh(&mpath->state_lock);
1166 	if (mpath->flags & MESH_PATH_RESOLVED ||
1167 			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1168 		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1169 		spin_unlock_bh(&mpath->state_lock);
1170 	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1171 		++mpath->discovery_retries;
1172 		mpath->discovery_timeout *= 2;
1173 		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1174 		spin_unlock_bh(&mpath->state_lock);
1175 		mesh_queue_preq(mpath, 0);
1176 	} else {
1177 		mpath->flags = 0;
1178 		mpath->exp_time = jiffies;
1179 		spin_unlock_bh(&mpath->state_lock);
1180 		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1181 			ret = mesh_path_send_to_gates(mpath);
1182 			if (ret)
1183 				mhwmp_dbg(sdata, "no gate was reachable\n");
1184 		} else
1185 			mesh_path_flush_pending(mpath);
1186 	}
1187 }
1188 
1189 void
1190 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1191 {
1192 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1193 	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1194 	u8 flags, target_flags = 0;
1195 
1196 	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1197 			? RANN_FLAG_IS_GATE : 0;
1198 
1199 	switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1200 	case IEEE80211_PROACTIVE_RANN:
1201 		mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1202 			       cpu_to_le32(++ifmsh->sn),
1203 			       0, NULL, 0, broadcast_addr,
1204 			       0, ifmsh->mshcfg.element_ttl,
1205 			       cpu_to_le32(interval), 0, 0, sdata);
1206 		break;
1207 	case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1208 		flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1209 	case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1210 		interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1211 		target_flags |= IEEE80211_PREQ_TO_FLAG |
1212 				IEEE80211_PREQ_USN_FLAG;
1213 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1214 				cpu_to_le32(++ifmsh->sn), target_flags,
1215 				(u8 *) broadcast_addr, 0, broadcast_addr,
1216 				0, ifmsh->mshcfg.element_ttl,
1217 				cpu_to_le32(interval),
1218 				0, cpu_to_le32(ifmsh->preq_id++), sdata);
1219 		break;
1220 	default:
1221 		mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1222 		return;
1223 	}
1224 }
1225