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 u32 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, __le32 orig_sn,
106				  u8 target_flags, const u8 *target,
107				  __le32 target_sn, const u8 *da,
108				  u8 hop_count, u8 ttl,
109				  __le32 lifetime, __le32 metric,
110				  __le32 preq_id,
111				  struct ieee80211_sub_if_data *sdata)
112{
113	struct ieee80211_local *local = sdata->local;
114	struct sk_buff *skb;
115	struct ieee80211_mgmt *mgmt;
116	u8 *pos, ie_len;
117	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
118		      sizeof(mgmt->u.action.u.mesh_action);
119
120	skb = dev_alloc_skb(local->tx_headroom +
121			    hdr_len +
122			    2 + 37); /* max HWMP IE */
123	if (!skb)
124		return -1;
125	skb_reserve(skb, local->tx_headroom);
126	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
127	memset(mgmt, 0, hdr_len);
128	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
129					  IEEE80211_STYPE_ACTION);
130
131	memcpy(mgmt->da, da, ETH_ALEN);
132	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
133	/* BSSID == SA */
134	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
135	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
136	mgmt->u.action.u.mesh_action.action_code =
137					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
138
139	switch (action) {
140	case MPATH_PREQ:
141		mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
142		ie_len = 37;
143		pos = skb_put(skb, 2 + ie_len);
144		*pos++ = WLAN_EID_PREQ;
145		break;
146	case MPATH_PREP:
147		mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
148		ie_len = 31;
149		pos = skb_put(skb, 2 + ie_len);
150		*pos++ = WLAN_EID_PREP;
151		break;
152	case MPATH_RANN:
153		mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
154		ie_len = sizeof(struct ieee80211_rann_ie);
155		pos = skb_put(skb, 2 + ie_len);
156		*pos++ = WLAN_EID_RANN;
157		break;
158	default:
159		kfree_skb(skb);
160		return -ENOTSUPP;
161		break;
162	}
163	*pos++ = ie_len;
164	*pos++ = flags;
165	*pos++ = hop_count;
166	*pos++ = ttl;
167	if (action == MPATH_PREP) {
168		memcpy(pos, target, ETH_ALEN);
169		pos += ETH_ALEN;
170		memcpy(pos, &target_sn, 4);
171		pos += 4;
172	} else {
173		if (action == MPATH_PREQ) {
174			memcpy(pos, &preq_id, 4);
175			pos += 4;
176		}
177		memcpy(pos, orig_addr, ETH_ALEN);
178		pos += ETH_ALEN;
179		memcpy(pos, &orig_sn, 4);
180		pos += 4;
181	}
182	memcpy(pos, &lifetime, 4);	/* interval for RANN */
183	pos += 4;
184	memcpy(pos, &metric, 4);
185	pos += 4;
186	if (action == MPATH_PREQ) {
187		*pos++ = 1; /* destination count */
188		*pos++ = target_flags;
189		memcpy(pos, target, ETH_ALEN);
190		pos += ETH_ALEN;
191		memcpy(pos, &target_sn, 4);
192		pos += 4;
193	} else if (action == MPATH_PREP) {
194		memcpy(pos, orig_addr, ETH_ALEN);
195		pos += ETH_ALEN;
196		memcpy(pos, &orig_sn, 4);
197		pos += 4;
198	}
199
200	ieee80211_tx_skb(sdata, skb);
201	return 0;
202}
203
204
205/*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
206 *  headroom in case the frame is encrypted. */
207static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
208		struct sk_buff *skb)
209{
210	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
211	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
212
213	skb_set_mac_header(skb, 0);
214	skb_set_network_header(skb, 0);
215	skb_set_transport_header(skb, 0);
216
217	/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
218	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
219	skb->priority = 7;
220
221	info->control.vif = &sdata->vif;
222	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
223	ieee80211_set_qos_hdr(sdata, skb);
224	ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
225}
226
227/**
228 * mesh_path_error_tx - Sends a PERR mesh management frame
229 *
230 * @ttl: allowed remaining hops
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 * @sdata: local mesh subif
236 *
237 * Note: This function may be called with driver locks taken that the driver
238 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
239 * frame directly but add it to the pending queue instead.
240 */
241int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
242		       u8 ttl, const u8 *target, __le32 target_sn,
243		       __le16 target_rcode, const u8 *ra)
244{
245	struct ieee80211_local *local = sdata->local;
246	struct sk_buff *skb;
247	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
248	struct ieee80211_mgmt *mgmt;
249	u8 *pos, ie_len;
250	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
251		      sizeof(mgmt->u.action.u.mesh_action);
252
253	if (time_before(jiffies, ifmsh->next_perr))
254		return -EAGAIN;
255
256	skb = dev_alloc_skb(local->tx_headroom +
257			    IEEE80211_ENCRYPT_HEADROOM +
258			    IEEE80211_ENCRYPT_TAILROOM +
259			    hdr_len +
260			    2 + 15 /* PERR IE */);
261	if (!skb)
262		return -1;
263	skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
264	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
265	memset(mgmt, 0, hdr_len);
266	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
267					  IEEE80211_STYPE_ACTION);
268
269	memcpy(mgmt->da, ra, ETH_ALEN);
270	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
271	/* BSSID == SA */
272	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
273	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
274	mgmt->u.action.u.mesh_action.action_code =
275					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
276	ie_len = 15;
277	pos = skb_put(skb, 2 + ie_len);
278	*pos++ = WLAN_EID_PERR;
279	*pos++ = ie_len;
280	/* ttl */
281	*pos++ = ttl;
282	/* number of destinations */
283	*pos++ = 1;
284	/*
285	 * flags bit, bit 1 is unset if we know the sequence number and
286	 * bit 2 is set if we have a reason code
287	 */
288	*pos = 0;
289	if (!target_sn)
290		*pos |= MP_F_USN;
291	if (target_rcode)
292		*pos |= MP_F_RCODE;
293	pos++;
294	memcpy(pos, target, ETH_ALEN);
295	pos += ETH_ALEN;
296	memcpy(pos, &target_sn, 4);
297	pos += 4;
298	memcpy(pos, &target_rcode, 2);
299
300	/* see note in function header */
301	prepare_frame_for_deferred_tx(sdata, skb);
302	ifmsh->next_perr = TU_TO_EXP_TIME(
303				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
304	ieee80211_add_pending_skb(local, skb);
305	return 0;
306}
307
308void ieee80211s_update_metric(struct ieee80211_local *local,
309		struct sta_info *sta, struct sk_buff *skb)
310{
311	struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
312	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
313	int failed;
314
315	if (!ieee80211_is_data(hdr->frame_control))
316		return;
317
318	failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
319
320	/* moving average, scaled to 100 */
321	sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
322	if (sta->fail_avg > 95)
323		mesh_plink_broken(sta);
324}
325
326static u32 airtime_link_metric_get(struct ieee80211_local *local,
327				   struct sta_info *sta)
328{
329	struct rate_info rinfo;
330	/* This should be adjusted for each device */
331	int device_constant = 1 << ARITH_SHIFT;
332	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
333	int s_unit = 1 << ARITH_SHIFT;
334	int rate, err;
335	u32 tx_time, estimated_retx;
336	u64 result;
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 * @action: type of hwmp ie
364 *
365 * This function updates the path routing information to the originator and the
366 * transmitter of a HWMP PREQ or PREP frame.
367 *
368 * Returns: metric to frame originator or 0 if the frame should not be further
369 * processed
370 *
371 * Notes: this function is the only place (besides user-provided info) where
372 * path routing information is updated.
373 */
374static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
375			       struct ieee80211_mgmt *mgmt,
376			       const u8 *hwmp_ie, enum mpath_frame_type action)
377{
378	struct ieee80211_local *local = sdata->local;
379	struct mesh_path *mpath;
380	struct sta_info *sta;
381	bool fresh_info;
382	const u8 *orig_addr, *ta;
383	u32 orig_sn, orig_metric;
384	unsigned long orig_lifetime, exp_time;
385	u32 last_hop_metric, new_metric;
386	bool process = true;
387
388	rcu_read_lock();
389	sta = sta_info_get(sdata, mgmt->sa);
390	if (!sta) {
391		rcu_read_unlock();
392		return 0;
393	}
394
395	last_hop_metric = airtime_link_metric_get(local, sta);
396	/* Update and check originator routing info */
397	fresh_info = true;
398
399	switch (action) {
400	case MPATH_PREQ:
401		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
402		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
403		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
404		orig_metric = PREQ_IE_METRIC(hwmp_ie);
405		break;
406	case MPATH_PREP:
407		/* Originator here refers to the MP that was the target in the
408		 * Path Request. We divert from the nomenclature in the draft
409		 * so that we can easily use a single function to gather path
410		 * information from both PREQ and PREP frames.
411		 */
412		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
413		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
414		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
415		orig_metric = PREP_IE_METRIC(hwmp_ie);
416		break;
417	default:
418		rcu_read_unlock();
419		return 0;
420	}
421	new_metric = orig_metric + last_hop_metric;
422	if (new_metric < orig_metric)
423		new_metric = MAX_METRIC;
424	exp_time = TU_TO_EXP_TIME(orig_lifetime);
425
426	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
427		/* This MP is the originator, we are not interested in this
428		 * frame, except for updating transmitter's path info.
429		 */
430		process = false;
431		fresh_info = false;
432	} else {
433		mpath = mesh_path_lookup(sdata, orig_addr);
434		if (mpath) {
435			spin_lock_bh(&mpath->state_lock);
436			if (mpath->flags & MESH_PATH_FIXED)
437				fresh_info = false;
438			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
439			    (mpath->flags & MESH_PATH_SN_VALID)) {
440				if (SN_GT(mpath->sn, orig_sn) ||
441				    (mpath->sn == orig_sn &&
442				     new_metric >= mpath->metric)) {
443					process = false;
444					fresh_info = false;
445				}
446			}
447		} else {
448			mpath = mesh_path_add(sdata, orig_addr);
449			if (IS_ERR(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 (ether_addr_equal(orig_addr, ta))
476		fresh_info = false;
477	else {
478		fresh_info = true;
479
480		mpath = mesh_path_lookup(sdata, ta);
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			mpath = mesh_path_add(sdata, ta);
489			if (IS_ERR(mpath)) {
490				rcu_read_unlock();
491				return 0;
492			}
493			spin_lock_bh(&mpath->state_lock);
494		}
495
496		if (fresh_info) {
497			mesh_path_assign_nexthop(mpath, sta);
498			mpath->metric = last_hop_metric;
499			mpath->exp_time = time_after(mpath->exp_time, exp_time)
500					  ?  mpath->exp_time : exp_time;
501			mesh_path_activate(mpath);
502			spin_unlock_bh(&mpath->state_lock);
503			mesh_path_tx_pending(mpath);
504		} else
505			spin_unlock_bh(&mpath->state_lock);
506	}
507
508	rcu_read_unlock();
509
510	return process ? new_metric : 0;
511}
512
513static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
514				    struct ieee80211_mgmt *mgmt,
515				    const u8 *preq_elem, u32 metric)
516{
517	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
518	struct mesh_path *mpath = NULL;
519	const u8 *target_addr, *orig_addr;
520	const u8 *da;
521	u8 target_flags, ttl, flags;
522	u32 orig_sn, target_sn, lifetime, orig_metric;
523	bool reply = false;
524	bool forward = true;
525	bool root_is_gate;
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	orig_metric = metric;
534	/* Proactive PREQ gate announcements */
535	flags = PREQ_IE_FLAGS(preq_elem);
536	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
537
538	mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
539
540	if (ether_addr_equal(target_addr, sdata->vif.addr)) {
541		mhwmp_dbg(sdata, "PREQ is for us\n");
542		forward = false;
543		reply = true;
544		metric = 0;
545		if (time_after(jiffies, ifmsh->last_sn_update +
546					net_traversal_jiffies(sdata)) ||
547		    time_before(jiffies, ifmsh->last_sn_update)) {
548			target_sn = ++ifmsh->sn;
549			ifmsh->last_sn_update = jiffies;
550		}
551	} else if (is_broadcast_ether_addr(target_addr) &&
552		   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
553		rcu_read_lock();
554		mpath = mesh_path_lookup(sdata, orig_addr);
555		if (mpath) {
556			if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
557				reply = true;
558				target_addr = sdata->vif.addr;
559				target_sn = ++ifmsh->sn;
560				metric = 0;
561				ifmsh->last_sn_update = jiffies;
562			}
563			if (root_is_gate)
564				mesh_path_add_gate(mpath);
565		}
566		rcu_read_unlock();
567	} else {
568		rcu_read_lock();
569		mpath = mesh_path_lookup(sdata, target_addr);
570		if (mpath) {
571			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
572					SN_LT(mpath->sn, target_sn)) {
573				mpath->sn = target_sn;
574				mpath->flags |= MESH_PATH_SN_VALID;
575			} else if ((!(target_flags & MP_F_DO)) &&
576					(mpath->flags & MESH_PATH_ACTIVE)) {
577				reply = true;
578				metric = mpath->metric;
579				target_sn = mpath->sn;
580				if (target_flags & MP_F_RF)
581					target_flags |= MP_F_DO;
582				else
583					forward = false;
584			}
585		}
586		rcu_read_unlock();
587	}
588
589	if (reply) {
590		lifetime = PREQ_IE_LIFETIME(preq_elem);
591		ttl = ifmsh->mshcfg.element_ttl;
592		if (ttl != 0) {
593			mhwmp_dbg(sdata, "replying to the PREQ\n");
594			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
595				cpu_to_le32(orig_sn), 0, target_addr,
596				cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
597				cpu_to_le32(lifetime), cpu_to_le32(metric),
598				0, sdata);
599		} else {
600			ifmsh->mshstats.dropped_frames_ttl++;
601		}
602	}
603
604	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
605		u32 preq_id;
606		u8 hopcount;
607
608		ttl = PREQ_IE_TTL(preq_elem);
609		lifetime = PREQ_IE_LIFETIME(preq_elem);
610		if (ttl <= 1) {
611			ifmsh->mshstats.dropped_frames_ttl++;
612			return;
613		}
614		mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
615		--ttl;
616		preq_id = PREQ_IE_PREQ_ID(preq_elem);
617		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
618		da = (mpath && mpath->is_root) ?
619			mpath->rann_snd_addr : broadcast_addr;
620
621		if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
622			target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
623			target_sn = PREQ_IE_TARGET_SN(preq_elem);
624			metric = orig_metric;
625		}
626
627		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
628				cpu_to_le32(orig_sn), target_flags, target_addr,
629				cpu_to_le32(target_sn), da,
630				hopcount, ttl, cpu_to_le32(lifetime),
631				cpu_to_le32(metric), cpu_to_le32(preq_id),
632				sdata);
633		if (!is_multicast_ether_addr(da))
634			ifmsh->mshstats.fwded_unicast++;
635		else
636			ifmsh->mshstats.fwded_mcast++;
637		ifmsh->mshstats.fwded_frames++;
638	}
639}
640
641
642static inline struct sta_info *
643next_hop_deref_protected(struct mesh_path *mpath)
644{
645	return rcu_dereference_protected(mpath->next_hop,
646					 lockdep_is_held(&mpath->state_lock));
647}
648
649
650static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
651				    struct ieee80211_mgmt *mgmt,
652				    const u8 *prep_elem, u32 metric)
653{
654	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
655	struct mesh_path *mpath;
656	const u8 *target_addr, *orig_addr;
657	u8 ttl, hopcount, flags;
658	u8 next_hop[ETH_ALEN];
659	u32 target_sn, orig_sn, lifetime;
660
661	mhwmp_dbg(sdata, "received PREP from %pM\n",
662		  PREP_IE_TARGET_ADDR(prep_elem));
663
664	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
665	if (ether_addr_equal(orig_addr, sdata->vif.addr))
666		/* destination, no forwarding required */
667		return;
668
669	if (!ifmsh->mshcfg.dot11MeshForwarding)
670		return;
671
672	ttl = PREP_IE_TTL(prep_elem);
673	if (ttl <= 1) {
674		sdata->u.mesh.mshstats.dropped_frames_ttl++;
675		return;
676	}
677
678	rcu_read_lock();
679	mpath = mesh_path_lookup(sdata, orig_addr);
680	if (mpath)
681		spin_lock_bh(&mpath->state_lock);
682	else
683		goto fail;
684	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
685		spin_unlock_bh(&mpath->state_lock);
686		goto fail;
687	}
688	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
689	spin_unlock_bh(&mpath->state_lock);
690	--ttl;
691	flags = PREP_IE_FLAGS(prep_elem);
692	lifetime = PREP_IE_LIFETIME(prep_elem);
693	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
694	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
695	target_sn = PREP_IE_TARGET_SN(prep_elem);
696	orig_sn = PREP_IE_ORIG_SN(prep_elem);
697
698	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
699		cpu_to_le32(orig_sn), 0, target_addr,
700		cpu_to_le32(target_sn), next_hop, hopcount,
701		ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
702		0, sdata);
703	rcu_read_unlock();
704
705	sdata->u.mesh.mshstats.fwded_unicast++;
706	sdata->u.mesh.mshstats.fwded_frames++;
707	return;
708
709fail:
710	rcu_read_unlock();
711	sdata->u.mesh.mshstats.dropped_frames_no_route++;
712}
713
714static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
715				    struct ieee80211_mgmt *mgmt,
716				    const u8 *perr_elem)
717{
718	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
719	struct mesh_path *mpath;
720	u8 ttl;
721	const u8 *ta, *target_addr;
722	u32 target_sn;
723	u16 target_rcode;
724
725	ta = mgmt->sa;
726	ttl = PERR_IE_TTL(perr_elem);
727	if (ttl <= 1) {
728		ifmsh->mshstats.dropped_frames_ttl++;
729		return;
730	}
731	ttl--;
732	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
733	target_sn = PERR_IE_TARGET_SN(perr_elem);
734	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
735
736	rcu_read_lock();
737	mpath = mesh_path_lookup(sdata, target_addr);
738	if (mpath) {
739		struct sta_info *sta;
740
741		spin_lock_bh(&mpath->state_lock);
742		sta = next_hop_deref_protected(mpath);
743		if (mpath->flags & MESH_PATH_ACTIVE &&
744		    ether_addr_equal(ta, sta->sta.addr) &&
745		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
746		    SN_GT(target_sn, mpath->sn))) {
747			mpath->flags &= ~MESH_PATH_ACTIVE;
748			mpath->sn = target_sn;
749			spin_unlock_bh(&mpath->state_lock);
750			if (!ifmsh->mshcfg.dot11MeshForwarding)
751				goto endperr;
752			mesh_path_error_tx(sdata, ttl, target_addr,
753					   cpu_to_le32(target_sn),
754					   cpu_to_le16(target_rcode),
755					   broadcast_addr);
756		} else
757			spin_unlock_bh(&mpath->state_lock);
758	}
759endperr:
760	rcu_read_unlock();
761}
762
763static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
764				    struct ieee80211_mgmt *mgmt,
765				    const struct ieee80211_rann_ie *rann)
766{
767	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
768	struct ieee80211_local *local = sdata->local;
769	struct sta_info *sta;
770	struct mesh_path *mpath;
771	u8 ttl, flags, hopcount;
772	const u8 *orig_addr;
773	u32 orig_sn, metric, metric_txsta, interval;
774	bool root_is_gate;
775
776	ttl = rann->rann_ttl;
777	flags = rann->rann_flags;
778	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
779	orig_addr = rann->rann_addr;
780	orig_sn = le32_to_cpu(rann->rann_seq);
781	interval = le32_to_cpu(rann->rann_interval);
782	hopcount = rann->rann_hopcount;
783	hopcount++;
784	metric = le32_to_cpu(rann->rann_metric);
785
786	/*  Ignore our own RANNs */
787	if (ether_addr_equal(orig_addr, sdata->vif.addr))
788		return;
789
790	mhwmp_dbg(sdata,
791		  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
792		  orig_addr, mgmt->sa, root_is_gate);
793
794	rcu_read_lock();
795	sta = sta_info_get(sdata, mgmt->sa);
796	if (!sta) {
797		rcu_read_unlock();
798		return;
799	}
800
801	metric_txsta = airtime_link_metric_get(local, sta);
802
803	mpath = mesh_path_lookup(sdata, orig_addr);
804	if (!mpath) {
805		mpath = mesh_path_add(sdata, orig_addr);
806		if (IS_ERR(mpath)) {
807			rcu_read_unlock();
808			sdata->u.mesh.mshstats.dropped_frames_no_route++;
809			return;
810		}
811	}
812
813	if (!(SN_LT(mpath->sn, orig_sn)) &&
814	    !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
815		rcu_read_unlock();
816		return;
817	}
818
819	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
820	     (time_after(jiffies, mpath->last_preq_to_root +
821				  root_path_confirmation_jiffies(sdata)) ||
822	     time_before(jiffies, mpath->last_preq_to_root))) &&
823	     !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
824		mhwmp_dbg(sdata,
825			  "time to refresh root mpath %pM\n",
826			  orig_addr);
827		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
828		mpath->last_preq_to_root = jiffies;
829	}
830
831	mpath->sn = orig_sn;
832	mpath->rann_metric = metric + metric_txsta;
833	mpath->is_root = true;
834	/* Recording RANNs sender address to send individually
835	 * addressed PREQs destined for root mesh STA */
836	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
837
838	if (root_is_gate)
839		mesh_path_add_gate(mpath);
840
841	if (ttl <= 1) {
842		ifmsh->mshstats.dropped_frames_ttl++;
843		rcu_read_unlock();
844		return;
845	}
846	ttl--;
847
848	if (ifmsh->mshcfg.dot11MeshForwarding) {
849		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
850				       cpu_to_le32(orig_sn),
851				       0, NULL, 0, broadcast_addr,
852				       hopcount, ttl, cpu_to_le32(interval),
853				       cpu_to_le32(metric + metric_txsta),
854				       0, sdata);
855	}
856
857	rcu_read_unlock();
858}
859
860
861void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
862			    struct ieee80211_mgmt *mgmt, size_t len)
863{
864	struct ieee802_11_elems elems;
865	size_t baselen;
866	u32 last_hop_metric;
867	struct sta_info *sta;
868
869	/* need action_code */
870	if (len < IEEE80211_MIN_ACTION_SIZE + 1)
871		return;
872
873	rcu_read_lock();
874	sta = sta_info_get(sdata, mgmt->sa);
875	if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
876		rcu_read_unlock();
877		return;
878	}
879	rcu_read_unlock();
880
881	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
882	ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
883			       len - baselen, false, &elems);
884
885	if (elems.preq) {
886		if (elems.preq_len != 37)
887			/* Right now we support just 1 destination and no AE */
888			return;
889		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
890						      MPATH_PREQ);
891		if (last_hop_metric)
892			hwmp_preq_frame_process(sdata, mgmt, elems.preq,
893						last_hop_metric);
894	}
895	if (elems.prep) {
896		if (elems.prep_len != 31)
897			/* Right now we support no AE */
898			return;
899		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
900						      MPATH_PREP);
901		if (last_hop_metric)
902			hwmp_prep_frame_process(sdata, mgmt, elems.prep,
903						last_hop_metric);
904	}
905	if (elems.perr) {
906		if (elems.perr_len != 15)
907			/* Right now we support only one destination per PERR */
908			return;
909		hwmp_perr_frame_process(sdata, mgmt, elems.perr);
910	}
911	if (elems.rann)
912		hwmp_rann_frame_process(sdata, mgmt, elems.rann);
913}
914
915/**
916 * mesh_queue_preq - queue a PREQ to a given destination
917 *
918 * @mpath: mesh path to discover
919 * @flags: special attributes of the PREQ to be sent
920 *
921 * Locking: the function must be called from within a rcu read lock block.
922 *
923 */
924static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
925{
926	struct ieee80211_sub_if_data *sdata = mpath->sdata;
927	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
928	struct mesh_preq_queue *preq_node;
929
930	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
931	if (!preq_node) {
932		mhwmp_dbg(sdata, "could not allocate PREQ node\n");
933		return;
934	}
935
936	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
937	if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
938		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
939		kfree(preq_node);
940		if (printk_ratelimit())
941			mhwmp_dbg(sdata, "PREQ node queue full\n");
942		return;
943	}
944
945	spin_lock(&mpath->state_lock);
946	if (mpath->flags & MESH_PATH_REQ_QUEUED) {
947		spin_unlock(&mpath->state_lock);
948		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
949		kfree(preq_node);
950		return;
951	}
952
953	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
954	preq_node->flags = flags;
955
956	mpath->flags |= MESH_PATH_REQ_QUEUED;
957	spin_unlock(&mpath->state_lock);
958
959	list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
960	++ifmsh->preq_queue_len;
961	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
962
963	if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
964		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
965
966	else if (time_before(jiffies, ifmsh->last_preq)) {
967		/* avoid long wait if did not send preqs for a long time
968		 * and jiffies wrapped around
969		 */
970		ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
971		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
972	} else
973		mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
974						min_preq_int_jiff(sdata));
975}
976
977/**
978 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
979 *
980 * @sdata: local mesh subif
981 */
982void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
983{
984	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
985	struct mesh_preq_queue *preq_node;
986	struct mesh_path *mpath;
987	u8 ttl, target_flags;
988	const u8 *da;
989	u32 lifetime;
990
991	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
992	if (!ifmsh->preq_queue_len ||
993		time_before(jiffies, ifmsh->last_preq +
994				min_preq_int_jiff(sdata))) {
995		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
996		return;
997	}
998
999	preq_node = list_first_entry(&ifmsh->preq_queue.list,
1000			struct mesh_preq_queue, list);
1001	list_del(&preq_node->list);
1002	--ifmsh->preq_queue_len;
1003	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1004
1005	rcu_read_lock();
1006	mpath = mesh_path_lookup(sdata, preq_node->dst);
1007	if (!mpath)
1008		goto enddiscovery;
1009
1010	spin_lock_bh(&mpath->state_lock);
1011	mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1012	if (preq_node->flags & PREQ_Q_F_START) {
1013		if (mpath->flags & MESH_PATH_RESOLVING) {
1014			spin_unlock_bh(&mpath->state_lock);
1015			goto enddiscovery;
1016		} else {
1017			mpath->flags &= ~MESH_PATH_RESOLVED;
1018			mpath->flags |= MESH_PATH_RESOLVING;
1019			mpath->discovery_retries = 0;
1020			mpath->discovery_timeout = disc_timeout_jiff(sdata);
1021		}
1022	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1023			mpath->flags & MESH_PATH_RESOLVED) {
1024		mpath->flags &= ~MESH_PATH_RESOLVING;
1025		spin_unlock_bh(&mpath->state_lock);
1026		goto enddiscovery;
1027	}
1028
1029	ifmsh->last_preq = jiffies;
1030
1031	if (time_after(jiffies, ifmsh->last_sn_update +
1032				net_traversal_jiffies(sdata)) ||
1033	    time_before(jiffies, ifmsh->last_sn_update)) {
1034		++ifmsh->sn;
1035		sdata->u.mesh.last_sn_update = jiffies;
1036	}
1037	lifetime = default_lifetime(sdata);
1038	ttl = sdata->u.mesh.mshcfg.element_ttl;
1039	if (ttl == 0) {
1040		sdata->u.mesh.mshstats.dropped_frames_ttl++;
1041		spin_unlock_bh(&mpath->state_lock);
1042		goto enddiscovery;
1043	}
1044
1045	if (preq_node->flags & PREQ_Q_F_REFRESH)
1046		target_flags = MP_F_DO;
1047	else
1048		target_flags = MP_F_RF;
1049
1050	spin_unlock_bh(&mpath->state_lock);
1051	da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1052	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1053			cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1054			cpu_to_le32(mpath->sn), da, 0,
1055			ttl, cpu_to_le32(lifetime), 0,
1056			cpu_to_le32(ifmsh->preq_id++), sdata);
1057	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1058
1059enddiscovery:
1060	rcu_read_unlock();
1061	kfree(preq_node);
1062}
1063
1064/**
1065 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1066 *
1067 * @skb: 802.11 frame to be sent
1068 * @sdata: network subif the frame will be sent through
1069 *
1070 * Lookup next hop for given skb and start path discovery if no
1071 * forwarding information is found.
1072 *
1073 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1074 * skb is freeed here if no mpath could be allocated.
1075 */
1076int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1077			 struct sk_buff *skb)
1078{
1079	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1080	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1081	struct mesh_path *mpath;
1082	struct sk_buff *skb_to_free = NULL;
1083	u8 *target_addr = hdr->addr3;
1084	int err = 0;
1085
1086	/* Nulls are only sent to peers for PS and should be pre-addressed */
1087	if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1088		return 0;
1089
1090	rcu_read_lock();
1091	err = mesh_nexthop_lookup(sdata, skb);
1092	if (!err)
1093		goto endlookup;
1094
1095	/* no nexthop found, start resolving */
1096	mpath = mesh_path_lookup(sdata, target_addr);
1097	if (!mpath) {
1098		mpath = mesh_path_add(sdata, target_addr);
1099		if (IS_ERR(mpath)) {
1100			mesh_path_discard_frame(sdata, skb);
1101			err = PTR_ERR(mpath);
1102			goto endlookup;
1103		}
1104	}
1105
1106	if (!(mpath->flags & MESH_PATH_RESOLVING))
1107		mesh_queue_preq(mpath, PREQ_Q_F_START);
1108
1109	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1110		skb_to_free = skb_dequeue(&mpath->frame_queue);
1111
1112	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1113	ieee80211_set_qos_hdr(sdata, skb);
1114	skb_queue_tail(&mpath->frame_queue, skb);
1115	err = -ENOENT;
1116	if (skb_to_free)
1117		mesh_path_discard_frame(sdata, skb_to_free);
1118
1119endlookup:
1120	rcu_read_unlock();
1121	return err;
1122}
1123
1124/**
1125 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1126 * this function is considered "using" the associated mpath, so preempt a path
1127 * refresh if this mpath expires soon.
1128 *
1129 * @skb: 802.11 frame to be sent
1130 * @sdata: network subif the frame will be sent through
1131 *
1132 * Returns: 0 if the next hop was found. Nonzero otherwise.
1133 */
1134int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1135			struct sk_buff *skb)
1136{
1137	struct mesh_path *mpath;
1138	struct sta_info *next_hop;
1139	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1140	u8 *target_addr = hdr->addr3;
1141	int err = -ENOENT;
1142
1143	rcu_read_lock();
1144	mpath = mesh_path_lookup(sdata, target_addr);
1145
1146	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1147		goto endlookup;
1148
1149	if (time_after(jiffies,
1150		       mpath->exp_time -
1151		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1152	    ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1153	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1154	    !(mpath->flags & MESH_PATH_FIXED))
1155		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1156
1157	next_hop = rcu_dereference(mpath->next_hop);
1158	if (next_hop) {
1159		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1160		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1161		ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1162		err = 0;
1163	}
1164
1165endlookup:
1166	rcu_read_unlock();
1167	return err;
1168}
1169
1170void mesh_path_timer(unsigned long data)
1171{
1172	struct mesh_path *mpath = (void *) data;
1173	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1174	int ret;
1175
1176	if (sdata->local->quiescing)
1177		return;
1178
1179	spin_lock_bh(&mpath->state_lock);
1180	if (mpath->flags & MESH_PATH_RESOLVED ||
1181			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1182		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1183		spin_unlock_bh(&mpath->state_lock);
1184	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1185		++mpath->discovery_retries;
1186		mpath->discovery_timeout *= 2;
1187		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1188		spin_unlock_bh(&mpath->state_lock);
1189		mesh_queue_preq(mpath, 0);
1190	} else {
1191		mpath->flags = 0;
1192		mpath->exp_time = jiffies;
1193		spin_unlock_bh(&mpath->state_lock);
1194		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1195			ret = mesh_path_send_to_gates(mpath);
1196			if (ret)
1197				mhwmp_dbg(sdata, "no gate was reachable\n");
1198		} else
1199			mesh_path_flush_pending(mpath);
1200	}
1201}
1202
1203void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1204{
1205	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1206	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1207	u8 flags, target_flags = 0;
1208
1209	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1210			? RANN_FLAG_IS_GATE : 0;
1211
1212	switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1213	case IEEE80211_PROACTIVE_RANN:
1214		mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1215			       cpu_to_le32(++ifmsh->sn),
1216			       0, NULL, 0, broadcast_addr,
1217			       0, ifmsh->mshcfg.element_ttl,
1218			       cpu_to_le32(interval), 0, 0, sdata);
1219		break;
1220	case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1221		flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1222	case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1223		interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1224		target_flags |= IEEE80211_PREQ_TO_FLAG |
1225				IEEE80211_PREQ_USN_FLAG;
1226		mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1227				cpu_to_le32(++ifmsh->sn), target_flags,
1228				(u8 *) broadcast_addr, 0, broadcast_addr,
1229				0, ifmsh->mshcfg.element_ttl,
1230				cpu_to_le32(interval),
1231				0, cpu_to_le32(ifmsh->preq_id++), sdata);
1232		break;
1233	default:
1234		mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1235		return;
1236	}
1237}
1238