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
31static void mesh_queue_preq(struct mesh_path *, u8);
32
33static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
34{
35	if (ae)
36		offset += 6;
37	return get_unaligned_le32(preq_elem + offset);
38}
39
40static inline u16 u16_field_get(const 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
95enum mpath_frame_type {
96	MPATH_PREQ = 0,
97	MPATH_PREP,
98	MPATH_PERR,
99	MPATH_RANN
100};
101
102static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
103
104static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
105				  const u8 *orig_addr, u32 orig_sn,
106				  u8 target_flags, const u8 *target,
107				  u32 target_sn, const u8 *da,
108				  u8 hop_count, u8 ttl,
109				  u32 lifetime, u32 metric, u32 preq_id,
110				  struct ieee80211_sub_if_data *sdata)
111{
112	struct ieee80211_local *local = sdata->local;
113	struct sk_buff *skb;
114	struct ieee80211_mgmt *mgmt;
115	u8 *pos, ie_len;
116	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
117		      sizeof(mgmt->u.action.u.mesh_action);
118
119	skb = dev_alloc_skb(local->tx_headroom +
120			    hdr_len +
121			    2 + 37); /* max HWMP IE */
122	if (!skb)
123		return -1;
124	skb_reserve(skb, local->tx_headroom);
125	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
126	memset(mgmt, 0, hdr_len);
127	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
128					  IEEE80211_STYPE_ACTION);
129
130	memcpy(mgmt->da, da, ETH_ALEN);
131	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
132	/* BSSID == SA */
133	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
134	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
135	mgmt->u.action.u.mesh_action.action_code =
136					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
137
138	switch (action) {
139	case MPATH_PREQ:
140		mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
141		ie_len = 37;
142		pos = skb_put(skb, 2 + ie_len);
143		*pos++ = WLAN_EID_PREQ;
144		break;
145	case MPATH_PREP:
146		mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
147		ie_len = 31;
148		pos = skb_put(skb, 2 + ie_len);
149		*pos++ = WLAN_EID_PREP;
150		break;
151	case MPATH_RANN:
152		mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
153		ie_len = sizeof(struct ieee80211_rann_ie);
154		pos = skb_put(skb, 2 + ie_len);
155		*pos++ = WLAN_EID_RANN;
156		break;
157	default:
158		kfree_skb(skb);
159		return -ENOTSUPP;
160	}
161	*pos++ = ie_len;
162	*pos++ = flags;
163	*pos++ = hop_count;
164	*pos++ = ttl;
165	if (action == MPATH_PREP) {
166		memcpy(pos, target, ETH_ALEN);
167		pos += ETH_ALEN;
168		put_unaligned_le32(target_sn, pos);
169		pos += 4;
170	} else {
171		if (action == MPATH_PREQ) {
172			put_unaligned_le32(preq_id, pos);
173			pos += 4;
174		}
175		memcpy(pos, orig_addr, ETH_ALEN);
176		pos += ETH_ALEN;
177		put_unaligned_le32(orig_sn, pos);
178		pos += 4;
179	}
180	put_unaligned_le32(lifetime, pos); /* interval for RANN */
181	pos += 4;
182	put_unaligned_le32(metric, pos);
183	pos += 4;
184	if (action == MPATH_PREQ) {
185		*pos++ = 1; /* destination count */
186		*pos++ = target_flags;
187		memcpy(pos, target, ETH_ALEN);
188		pos += ETH_ALEN;
189		put_unaligned_le32(target_sn, pos);
190		pos += 4;
191	} else if (action == MPATH_PREP) {
192		memcpy(pos, orig_addr, ETH_ALEN);
193		pos += ETH_ALEN;
194		put_unaligned_le32(orig_sn, pos);
195		pos += 4;
196	}
197
198	ieee80211_tx_skb(sdata, skb);
199	return 0;
200}
201
202
203/*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
204 *  headroom in case the frame is encrypted. */
205static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
206		struct sk_buff *skb)
207{
208	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
209	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
210
211	skb_set_mac_header(skb, 0);
212	skb_set_network_header(skb, 0);
213	skb_set_transport_header(skb, 0);
214
215	/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
216	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
217	skb->priority = 7;
218
219	info->control.vif = &sdata->vif;
220	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
221	ieee80211_set_qos_hdr(sdata, skb);
222	ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
223}
224
225/**
226 * mesh_path_error_tx - Sends a PERR mesh management frame
227 *
228 * @ttl: allowed remaining hops
229 * @target: broken destination
230 * @target_sn: SN of the broken destination
231 * @target_rcode: reason code for this PERR
232 * @ra: node this frame is addressed to
233 * @sdata: local mesh subif
234 *
235 * Note: This function may be called with driver locks taken that the driver
236 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
237 * frame directly but add it to the pending queue instead.
238 */
239int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
240		       u8 ttl, const u8 *target, u32 target_sn,
241		       u16 target_rcode, const u8 *ra)
242{
243	struct ieee80211_local *local = sdata->local;
244	struct sk_buff *skb;
245	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
246	struct ieee80211_mgmt *mgmt;
247	u8 *pos, ie_len;
248	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
249		      sizeof(mgmt->u.action.u.mesh_action);
250
251	if (time_before(jiffies, ifmsh->next_perr))
252		return -EAGAIN;
253
254	skb = dev_alloc_skb(local->tx_headroom +
255			    sdata->encrypt_headroom +
256			    IEEE80211_ENCRYPT_TAILROOM +
257			    hdr_len +
258			    2 + 15 /* PERR IE */);
259	if (!skb)
260		return -1;
261	skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
262	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
263	memset(mgmt, 0, hdr_len);
264	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
265					  IEEE80211_STYPE_ACTION);
266
267	memcpy(mgmt->da, ra, ETH_ALEN);
268	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
269	/* BSSID == SA */
270	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
271	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
272	mgmt->u.action.u.mesh_action.action_code =
273					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
274	ie_len = 15;
275	pos = skb_put(skb, 2 + ie_len);
276	*pos++ = WLAN_EID_PERR;
277	*pos++ = ie_len;
278	/* ttl */
279	*pos++ = ttl;
280	/* number of destinations */
281	*pos++ = 1;
282	/*
283	 * flags bit, bit 1 is unset if we know the sequence number and
284	 * bit 2 is set if we have a reason code
285	 */
286	*pos = 0;
287	if (!target_sn)
288		*pos |= MP_F_USN;
289	if (target_rcode)
290		*pos |= MP_F_RCODE;
291	pos++;
292	memcpy(pos, target, ETH_ALEN);
293	pos += ETH_ALEN;
294	put_unaligned_le32(target_sn, pos);
295	pos += 4;
296	put_unaligned_le16(target_rcode, pos);
297
298	/* see note in function header */
299	prepare_frame_for_deferred_tx(sdata, skb);
300	ifmsh->next_perr = TU_TO_EXP_TIME(
301				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
302	ieee80211_add_pending_skb(local, skb);
303	return 0;
304}
305
306void ieee80211s_update_metric(struct ieee80211_local *local,
307		struct sta_info *sta, struct sk_buff *skb)
308{
309	struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
310	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
311	int failed;
312
313	if (!ieee80211_is_data(hdr->frame_control))
314		return;
315
316	failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
317
318	/* moving average, scaled to 100 */
319	sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
320	if (sta->fail_avg > 95)
321		mesh_plink_broken(sta);
322}
323
324static u32 airtime_link_metric_get(struct ieee80211_local *local,
325				   struct sta_info *sta)
326{
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	if (sta->fail_avg >= 100)
337		return MAX_METRIC;
338
339	sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
340	rate = cfg80211_calculate_bitrate(&rinfo);
341	if (WARN_ON(!rate))
342		return MAX_METRIC;
343
344	err = (sta->fail_avg << ARITH_SHIFT) / 100;
345
346	/* bitrate is in units of 100 Kbps, while we need rate in units of
347	 * 1Mbps. This will be corrected on tx_time computation.
348	 */
349	tx_time = (device_constant + 10 * test_frame_len / rate);
350	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
351	result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
352	return (u32)result;
353}
354
355/**
356 * hwmp_route_info_get - Update routing info to originator and transmitter
357 *
358 * @sdata: local mesh subif
359 * @mgmt: mesh management frame
360 * @hwmp_ie: hwmp information element (PREP or PREQ)
361 * @action: type of hwmp ie
362 *
363 * This function updates the path routing information to the originator and the
364 * transmitter of a HWMP PREQ or PREP frame.
365 *
366 * Returns: metric to frame originator or 0 if the frame should not be further
367 * processed
368 *
369 * Notes: this function is the only place (besides user-provided info) where
370 * path routing information is updated.
371 */
372static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
373			       struct ieee80211_mgmt *mgmt,
374			       const u8 *hwmp_ie, enum mpath_frame_type action)
375{
376	struct ieee80211_local *local = sdata->local;
377	struct mesh_path *mpath;
378	struct sta_info *sta;
379	bool fresh_info;
380	const u8 *orig_addr, *ta;
381	u32 orig_sn, orig_metric;
382	unsigned long orig_lifetime, exp_time;
383	u32 last_hop_metric, new_metric;
384	bool process = true;
385
386	rcu_read_lock();
387	sta = sta_info_get(sdata, mgmt->sa);
388	if (!sta) {
389		rcu_read_unlock();
390		return 0;
391	}
392
393	last_hop_metric = airtime_link_metric_get(local, sta);
394	/* Update and check originator routing info */
395	fresh_info = true;
396
397	switch (action) {
398	case MPATH_PREQ:
399		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
400		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
401		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
402		orig_metric = PREQ_IE_METRIC(hwmp_ie);
403		break;
404	case MPATH_PREP:
405		/* Originator here refers to the MP that was the target in the
406		 * Path Request. We divert from the nomenclature in the draft
407		 * so that we can easily use a single function to gather path
408		 * information from both PREQ and PREP frames.
409		 */
410		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
411		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
412		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
413		orig_metric = PREP_IE_METRIC(hwmp_ie);
414		break;
415	default:
416		rcu_read_unlock();
417		return 0;
418	}
419	new_metric = orig_metric + last_hop_metric;
420	if (new_metric < orig_metric)
421		new_metric = MAX_METRIC;
422	exp_time = TU_TO_EXP_TIME(orig_lifetime);
423
424	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
425		/* This MP is the originator, we are not interested in this
426		 * frame, except for updating transmitter's path info.
427		 */
428		process = false;
429		fresh_info = false;
430	} else {
431		mpath = mesh_path_lookup(sdata, orig_addr);
432		if (mpath) {
433			spin_lock_bh(&mpath->state_lock);
434			if (mpath->flags & MESH_PATH_FIXED)
435				fresh_info = false;
436			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
437			    (mpath->flags & MESH_PATH_SN_VALID)) {
438				if (SN_GT(mpath->sn, orig_sn) ||
439				    (mpath->sn == orig_sn &&
440				     new_metric >= mpath->metric)) {
441					process = false;
442					fresh_info = false;
443				}
444			}
445		} else {
446			mpath = mesh_path_add(sdata, orig_addr);
447			if (IS_ERR(mpath)) {
448				rcu_read_unlock();
449				return 0;
450			}
451			spin_lock_bh(&mpath->state_lock);
452		}
453
454		if (fresh_info) {
455			mesh_path_assign_nexthop(mpath, sta);
456			mpath->flags |= MESH_PATH_SN_VALID;
457			mpath->metric = new_metric;
458			mpath->sn = orig_sn;
459			mpath->exp_time = time_after(mpath->exp_time, exp_time)
460					  ?  mpath->exp_time : exp_time;
461			mesh_path_activate(mpath);
462			spin_unlock_bh(&mpath->state_lock);
463			mesh_path_tx_pending(mpath);
464			/* draft says preq_id should be saved to, but there does
465			 * not seem to be any use for it, skipping by now
466			 */
467		} else
468			spin_unlock_bh(&mpath->state_lock);
469	}
470
471	/* Update and check transmitter routing info */
472	ta = mgmt->sa;
473	if (ether_addr_equal(orig_addr, ta))
474		fresh_info = false;
475	else {
476		fresh_info = true;
477
478		mpath = mesh_path_lookup(sdata, ta);
479		if (mpath) {
480			spin_lock_bh(&mpath->state_lock);
481			if ((mpath->flags & MESH_PATH_FIXED) ||
482				((mpath->flags & MESH_PATH_ACTIVE) &&
483					(last_hop_metric > mpath->metric)))
484				fresh_info = false;
485		} else {
486			mpath = mesh_path_add(sdata, ta);
487			if (IS_ERR(mpath)) {
488				rcu_read_unlock();
489				return 0;
490			}
491			spin_lock_bh(&mpath->state_lock);
492		}
493
494		if (fresh_info) {
495			mesh_path_assign_nexthop(mpath, sta);
496			mpath->metric = last_hop_metric;
497			mpath->exp_time = time_after(mpath->exp_time, exp_time)
498					  ?  mpath->exp_time : exp_time;
499			mesh_path_activate(mpath);
500			spin_unlock_bh(&mpath->state_lock);
501			mesh_path_tx_pending(mpath);
502		} else
503			spin_unlock_bh(&mpath->state_lock);
504	}
505
506	rcu_read_unlock();
507
508	return process ? new_metric : 0;
509}
510
511static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
512				    struct ieee80211_mgmt *mgmt,
513				    const u8 *preq_elem, u32 metric)
514{
515	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
516	struct mesh_path *mpath = NULL;
517	const u8 *target_addr, *orig_addr;
518	const u8 *da;
519	u8 target_flags, ttl, flags;
520	u32 orig_sn, target_sn, lifetime, orig_metric;
521	bool reply = false;
522	bool forward = true;
523	bool root_is_gate;
524
525	/* Update target SN, if present */
526	target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
527	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
528	target_sn = PREQ_IE_TARGET_SN(preq_elem);
529	orig_sn = PREQ_IE_ORIG_SN(preq_elem);
530	target_flags = PREQ_IE_TARGET_F(preq_elem);
531	orig_metric = metric;
532	/* Proactive PREQ gate announcements */
533	flags = PREQ_IE_FLAGS(preq_elem);
534	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
535
536	mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
537
538	if (ether_addr_equal(target_addr, sdata->vif.addr)) {
539		mhwmp_dbg(sdata, "PREQ is for us\n");
540		forward = false;
541		reply = true;
542		metric = 0;
543		if (time_after(jiffies, ifmsh->last_sn_update +
544					net_traversal_jiffies(sdata)) ||
545		    time_before(jiffies, ifmsh->last_sn_update)) {
546			++ifmsh->sn;
547			ifmsh->last_sn_update = jiffies;
548		}
549		target_sn = ifmsh->sn;
550	} else if (is_broadcast_ether_addr(target_addr) &&
551		   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
552		rcu_read_lock();
553		mpath = mesh_path_lookup(sdata, orig_addr);
554		if (mpath) {
555			if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
556				reply = true;
557				target_addr = sdata->vif.addr;
558				target_sn = ++ifmsh->sn;
559				metric = 0;
560				ifmsh->last_sn_update = jiffies;
561			}
562			if (root_is_gate)
563				mesh_path_add_gate(mpath);
564		}
565		rcu_read_unlock();
566	} else {
567		rcu_read_lock();
568		mpath = mesh_path_lookup(sdata, target_addr);
569		if (mpath) {
570			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
571					SN_LT(mpath->sn, target_sn)) {
572				mpath->sn = target_sn;
573				mpath->flags |= MESH_PATH_SN_VALID;
574			} else if ((!(target_flags & MP_F_DO)) &&
575					(mpath->flags & MESH_PATH_ACTIVE)) {
576				reply = true;
577				metric = mpath->metric;
578				target_sn = mpath->sn;
579				if (target_flags & MP_F_RF)
580					target_flags |= MP_F_DO;
581				else
582					forward = false;
583			}
584		}
585		rcu_read_unlock();
586	}
587
588	if (reply) {
589		lifetime = PREQ_IE_LIFETIME(preq_elem);
590		ttl = ifmsh->mshcfg.element_ttl;
591		if (ttl != 0) {
592			mhwmp_dbg(sdata, "replying to the PREQ\n");
593			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
594					       orig_sn, 0, target_addr,
595					       target_sn, mgmt->sa, 0, ttl,
596					       lifetime, metric, 0, sdata);
597		} else {
598			ifmsh->mshstats.dropped_frames_ttl++;
599		}
600	}
601
602	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
603		u32 preq_id;
604		u8 hopcount;
605
606		ttl = PREQ_IE_TTL(preq_elem);
607		lifetime = PREQ_IE_LIFETIME(preq_elem);
608		if (ttl <= 1) {
609			ifmsh->mshstats.dropped_frames_ttl++;
610			return;
611		}
612		mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
613		--ttl;
614		preq_id = PREQ_IE_PREQ_ID(preq_elem);
615		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
616		da = (mpath && mpath->is_root) ?
617			mpath->rann_snd_addr : broadcast_addr;
618
619		if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
620			target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
621			target_sn = PREQ_IE_TARGET_SN(preq_elem);
622			metric = orig_metric;
623		}
624
625		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
626				       orig_sn, target_flags, target_addr,
627				       target_sn, da, hopcount, ttl, lifetime,
628				       metric, preq_id, sdata);
629		if (!is_multicast_ether_addr(da))
630			ifmsh->mshstats.fwded_unicast++;
631		else
632			ifmsh->mshstats.fwded_mcast++;
633		ifmsh->mshstats.fwded_frames++;
634	}
635}
636
637
638static inline struct sta_info *
639next_hop_deref_protected(struct mesh_path *mpath)
640{
641	return rcu_dereference_protected(mpath->next_hop,
642					 lockdep_is_held(&mpath->state_lock));
643}
644
645
646static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
647				    struct ieee80211_mgmt *mgmt,
648				    const u8 *prep_elem, u32 metric)
649{
650	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
651	struct mesh_path *mpath;
652	const u8 *target_addr, *orig_addr;
653	u8 ttl, hopcount, flags;
654	u8 next_hop[ETH_ALEN];
655	u32 target_sn, orig_sn, lifetime;
656
657	mhwmp_dbg(sdata, "received PREP from %pM\n",
658		  PREP_IE_TARGET_ADDR(prep_elem));
659
660	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
661	if (ether_addr_equal(orig_addr, sdata->vif.addr))
662		/* destination, no forwarding required */
663		return;
664
665	if (!ifmsh->mshcfg.dot11MeshForwarding)
666		return;
667
668	ttl = PREP_IE_TTL(prep_elem);
669	if (ttl <= 1) {
670		sdata->u.mesh.mshstats.dropped_frames_ttl++;
671		return;
672	}
673
674	rcu_read_lock();
675	mpath = mesh_path_lookup(sdata, orig_addr);
676	if (mpath)
677		spin_lock_bh(&mpath->state_lock);
678	else
679		goto fail;
680	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
681		spin_unlock_bh(&mpath->state_lock);
682		goto fail;
683	}
684	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
685	spin_unlock_bh(&mpath->state_lock);
686	--ttl;
687	flags = PREP_IE_FLAGS(prep_elem);
688	lifetime = PREP_IE_LIFETIME(prep_elem);
689	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
690	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
691	target_sn = PREP_IE_TARGET_SN(prep_elem);
692	orig_sn = PREP_IE_ORIG_SN(prep_elem);
693
694	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
695			       target_addr, target_sn, next_hop, hopcount,
696			       ttl, lifetime, metric, 0, sdata);
697	rcu_read_unlock();
698
699	sdata->u.mesh.mshstats.fwded_unicast++;
700	sdata->u.mesh.mshstats.fwded_frames++;
701	return;
702
703fail:
704	rcu_read_unlock();
705	sdata->u.mesh.mshstats.dropped_frames_no_route++;
706}
707
708static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
709				    struct ieee80211_mgmt *mgmt,
710				    const u8 *perr_elem)
711{
712	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
713	struct mesh_path *mpath;
714	u8 ttl;
715	const u8 *ta, *target_addr;
716	u32 target_sn;
717	u16 target_rcode;
718
719	ta = mgmt->sa;
720	ttl = PERR_IE_TTL(perr_elem);
721	if (ttl <= 1) {
722		ifmsh->mshstats.dropped_frames_ttl++;
723		return;
724	}
725	ttl--;
726	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
727	target_sn = PERR_IE_TARGET_SN(perr_elem);
728	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
729
730	rcu_read_lock();
731	mpath = mesh_path_lookup(sdata, target_addr);
732	if (mpath) {
733		struct sta_info *sta;
734
735		spin_lock_bh(&mpath->state_lock);
736		sta = next_hop_deref_protected(mpath);
737		if (mpath->flags & MESH_PATH_ACTIVE &&
738		    ether_addr_equal(ta, sta->sta.addr) &&
739		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
740		    SN_GT(target_sn, mpath->sn))) {
741			mpath->flags &= ~MESH_PATH_ACTIVE;
742			mpath->sn = target_sn;
743			spin_unlock_bh(&mpath->state_lock);
744			if (!ifmsh->mshcfg.dot11MeshForwarding)
745				goto endperr;
746			mesh_path_error_tx(sdata, ttl, target_addr,
747					   target_sn, target_rcode,
748					   broadcast_addr);
749		} else
750			spin_unlock_bh(&mpath->state_lock);
751	}
752endperr:
753	rcu_read_unlock();
754}
755
756static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
757				    struct ieee80211_mgmt *mgmt,
758				    const struct ieee80211_rann_ie *rann)
759{
760	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
761	struct ieee80211_local *local = sdata->local;
762	struct sta_info *sta;
763	struct mesh_path *mpath;
764	u8 ttl, flags, hopcount;
765	const u8 *orig_addr;
766	u32 orig_sn, metric, metric_txsta, interval;
767	bool root_is_gate;
768
769	ttl = rann->rann_ttl;
770	flags = rann->rann_flags;
771	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
772	orig_addr = rann->rann_addr;
773	orig_sn = le32_to_cpu(rann->rann_seq);
774	interval = le32_to_cpu(rann->rann_interval);
775	hopcount = rann->rann_hopcount;
776	hopcount++;
777	metric = le32_to_cpu(rann->rann_metric);
778
779	/*  Ignore our own RANNs */
780	if (ether_addr_equal(orig_addr, sdata->vif.addr))
781		return;
782
783	mhwmp_dbg(sdata,
784		  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
785		  orig_addr, mgmt->sa, root_is_gate);
786
787	rcu_read_lock();
788	sta = sta_info_get(sdata, mgmt->sa);
789	if (!sta) {
790		rcu_read_unlock();
791		return;
792	}
793
794	metric_txsta = airtime_link_metric_get(local, sta);
795
796	mpath = mesh_path_lookup(sdata, orig_addr);
797	if (!mpath) {
798		mpath = mesh_path_add(sdata, orig_addr);
799		if (IS_ERR(mpath)) {
800			rcu_read_unlock();
801			sdata->u.mesh.mshstats.dropped_frames_no_route++;
802			return;
803		}
804	}
805
806	if (!(SN_LT(mpath->sn, orig_sn)) &&
807	    !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
808		rcu_read_unlock();
809		return;
810	}
811
812	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
813	     (time_after(jiffies, mpath->last_preq_to_root +
814				  root_path_confirmation_jiffies(sdata)) ||
815	     time_before(jiffies, mpath->last_preq_to_root))) &&
816	     !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
817		mhwmp_dbg(sdata,
818			  "time to refresh root mpath %pM\n",
819			  orig_addr);
820		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
821		mpath->last_preq_to_root = jiffies;
822	}
823
824	mpath->sn = orig_sn;
825	mpath->rann_metric = metric + metric_txsta;
826	mpath->is_root = true;
827	/* Recording RANNs sender address to send individually
828	 * addressed PREQs destined for root mesh STA */
829	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
830
831	if (root_is_gate)
832		mesh_path_add_gate(mpath);
833
834	if (ttl <= 1) {
835		ifmsh->mshstats.dropped_frames_ttl++;
836		rcu_read_unlock();
837		return;
838	}
839	ttl--;
840
841	if (ifmsh->mshcfg.dot11MeshForwarding) {
842		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
843				       orig_sn, 0, NULL, 0, broadcast_addr,
844				       hopcount, ttl, interval,
845				       metric + metric_txsta, 0, sdata);
846	}
847
848	rcu_read_unlock();
849}
850
851
852void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
853			    struct ieee80211_mgmt *mgmt, 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, false, &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 */
915static 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 */
973void 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(sdata, preq_node->dst);
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, ifmsh->sn,
1044			       target_flags, mpath->dst, mpath->sn, da, 0,
1045			       ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1046	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1047
1048enddiscovery:
1049	rcu_read_unlock();
1050	kfree(preq_node);
1051}
1052
1053/**
1054 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1055 *
1056 * @skb: 802.11 frame to be sent
1057 * @sdata: network subif the frame will be sent through
1058 *
1059 * Lookup next hop for given skb and start path discovery if no
1060 * forwarding information is found.
1061 *
1062 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1063 * skb is freeed here if no mpath could be allocated.
1064 */
1065int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1066			 struct sk_buff *skb)
1067{
1068	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1069	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1070	struct mesh_path *mpath;
1071	struct sk_buff *skb_to_free = NULL;
1072	u8 *target_addr = hdr->addr3;
1073	int err = 0;
1074
1075	/* Nulls are only sent to peers for PS and should be pre-addressed */
1076	if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1077		return 0;
1078
1079	rcu_read_lock();
1080	err = mesh_nexthop_lookup(sdata, skb);
1081	if (!err)
1082		goto endlookup;
1083
1084	/* no nexthop found, start resolving */
1085	mpath = mesh_path_lookup(sdata, target_addr);
1086	if (!mpath) {
1087		mpath = mesh_path_add(sdata, target_addr);
1088		if (IS_ERR(mpath)) {
1089			mesh_path_discard_frame(sdata, skb);
1090			err = PTR_ERR(mpath);
1091			goto endlookup;
1092		}
1093	}
1094
1095	if (!(mpath->flags & MESH_PATH_RESOLVING))
1096		mesh_queue_preq(mpath, PREQ_Q_F_START);
1097
1098	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1099		skb_to_free = skb_dequeue(&mpath->frame_queue);
1100
1101	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1102	ieee80211_set_qos_hdr(sdata, skb);
1103	skb_queue_tail(&mpath->frame_queue, skb);
1104	err = -ENOENT;
1105	if (skb_to_free)
1106		mesh_path_discard_frame(sdata, skb_to_free);
1107
1108endlookup:
1109	rcu_read_unlock();
1110	return err;
1111}
1112
1113/**
1114 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1115 * this function is considered "using" the associated mpath, so preempt a path
1116 * refresh if this mpath expires soon.
1117 *
1118 * @skb: 802.11 frame to be sent
1119 * @sdata: network subif the frame will be sent through
1120 *
1121 * Returns: 0 if the next hop was found. Nonzero otherwise.
1122 */
1123int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1124			struct sk_buff *skb)
1125{
1126	struct mesh_path *mpath;
1127	struct sta_info *next_hop;
1128	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1129	u8 *target_addr = hdr->addr3;
1130	int err = -ENOENT;
1131
1132	rcu_read_lock();
1133	mpath = mesh_path_lookup(sdata, target_addr);
1134
1135	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1136		goto endlookup;
1137
1138	if (time_after(jiffies,
1139		       mpath->exp_time -
1140		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1141	    ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1142	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1143	    !(mpath->flags & MESH_PATH_FIXED))
1144		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1145
1146	next_hop = rcu_dereference(mpath->next_hop);
1147	if (next_hop) {
1148		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1149		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1150		ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1151		err = 0;
1152	}
1153
1154endlookup:
1155	rcu_read_unlock();
1156	return err;
1157}
1158
1159void mesh_path_timer(unsigned long data)
1160{
1161	struct mesh_path *mpath = (void *) data;
1162	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1163	int ret;
1164
1165	if (sdata->local->quiescing)
1166		return;
1167
1168	spin_lock_bh(&mpath->state_lock);
1169	if (mpath->flags & MESH_PATH_RESOLVED ||
1170			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1171		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1172		spin_unlock_bh(&mpath->state_lock);
1173	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1174		++mpath->discovery_retries;
1175		mpath->discovery_timeout *= 2;
1176		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1177		spin_unlock_bh(&mpath->state_lock);
1178		mesh_queue_preq(mpath, 0);
1179	} else {
1180		mpath->flags = 0;
1181		mpath->exp_time = jiffies;
1182		spin_unlock_bh(&mpath->state_lock);
1183		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1184			ret = mesh_path_send_to_gates(mpath);
1185			if (ret)
1186				mhwmp_dbg(sdata, "no gate was reachable\n");
1187		} else
1188			mesh_path_flush_pending(mpath);
1189	}
1190}
1191
1192void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1193{
1194	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1195	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1196	u8 flags, target_flags = 0;
1197
1198	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1199			? RANN_FLAG_IS_GATE : 0;
1200
1201	switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1202	case IEEE80211_PROACTIVE_RANN:
1203		mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1204				       ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1205				       0, ifmsh->mshcfg.element_ttl,
1206				       interval, 0, 0, sdata);
1207		break;
1208	case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1209		flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1210	case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1211		interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1212		target_flags |= IEEE80211_PREQ_TO_FLAG |
1213				IEEE80211_PREQ_USN_FLAG;
1214		mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1215				       ++ifmsh->sn, target_flags,
1216				       (u8 *) broadcast_addr, 0, broadcast_addr,
1217				       0, ifmsh->mshcfg.element_ttl, interval,
1218				       0, ifmsh->preq_id++, sdata);
1219		break;
1220	default:
1221		mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1222		return;
1223	}
1224}
1225