1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Copyright (C) 2019, 2021-2022 Intel Corporation
5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/etherdevice.h>
10 #include <asm/unaligned.h>
11 #include "wme.h"
12 #include "mesh.h"
13 
14 #define TEST_FRAME_LEN	8192
15 #define MAX_METRIC	0xffffffff
16 #define ARITH_SHIFT	8
17 #define LINK_FAIL_THRESH 95
18 
19 #define MAX_PREQ_QUEUE_LEN	64
20 
21 static void mesh_queue_preq(struct mesh_path *, u8);
22 
u32_field_get(const u8 * preq_elem,int offset,bool ae)23 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
24 {
25 	if (ae)
26 		offset += 6;
27 	return get_unaligned_le32(preq_elem + offset);
28 }
29 
u16_field_get(const u8 * preq_elem,int offset,bool ae)30 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
31 {
32 	if (ae)
33 		offset += 6;
34 	return get_unaligned_le16(preq_elem + offset);
35 }
36 
37 /* HWMP IE processing macros */
38 #define AE_F			(1<<6)
39 #define AE_F_SET(x)		(*x & AE_F)
40 #define PREQ_IE_FLAGS(x)	(*(x))
41 #define PREQ_IE_HOPCOUNT(x)	(*(x + 1))
42 #define PREQ_IE_TTL(x)		(*(x + 2))
43 #define PREQ_IE_PREQ_ID(x)	u32_field_get(x, 3, 0)
44 #define PREQ_IE_ORIG_ADDR(x)	(x + 7)
45 #define PREQ_IE_ORIG_SN(x)	u32_field_get(x, 13, 0)
46 #define PREQ_IE_LIFETIME(x)	u32_field_get(x, 17, AE_F_SET(x))
47 #define PREQ_IE_METRIC(x) 	u32_field_get(x, 21, AE_F_SET(x))
48 #define PREQ_IE_TARGET_F(x)	(*(AE_F_SET(x) ? x + 32 : x + 26))
49 #define PREQ_IE_TARGET_ADDR(x) 	(AE_F_SET(x) ? x + 33 : x + 27)
50 #define PREQ_IE_TARGET_SN(x) 	u32_field_get(x, 33, AE_F_SET(x))
51 
52 
53 #define PREP_IE_FLAGS(x)	PREQ_IE_FLAGS(x)
54 #define PREP_IE_HOPCOUNT(x)	PREQ_IE_HOPCOUNT(x)
55 #define PREP_IE_TTL(x)		PREQ_IE_TTL(x)
56 #define PREP_IE_ORIG_ADDR(x)	(AE_F_SET(x) ? x + 27 : x + 21)
57 #define PREP_IE_ORIG_SN(x)	u32_field_get(x, 27, AE_F_SET(x))
58 #define PREP_IE_LIFETIME(x)	u32_field_get(x, 13, AE_F_SET(x))
59 #define PREP_IE_METRIC(x)	u32_field_get(x, 17, AE_F_SET(x))
60 #define PREP_IE_TARGET_ADDR(x)	(x + 3)
61 #define PREP_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
62 
63 #define PERR_IE_TTL(x)		(*(x))
64 #define PERR_IE_TARGET_FLAGS(x)	(*(x + 2))
65 #define PERR_IE_TARGET_ADDR(x)	(x + 3)
66 #define PERR_IE_TARGET_SN(x)	u32_field_get(x, 9, 0)
67 #define PERR_IE_TARGET_RCODE(x)	u16_field_get(x, 13, 0)
68 
69 #define MSEC_TO_TU(x) (x*1000/1024)
70 #define SN_GT(x, y) ((s32)(y - x) < 0)
71 #define SN_LT(x, y) ((s32)(x - y) < 0)
72 #define MAX_SANE_SN_DELTA 32
73 
SN_DELTA(u32 x,u32 y)74 static inline u32 SN_DELTA(u32 x, u32 y)
75 {
76 	return x >= y ? x - y : y - x;
77 }
78 
79 #define net_traversal_jiffies(s) \
80 	msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
81 #define default_lifetime(s) \
82 	MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
83 #define min_preq_int_jiff(s) \
84 	(msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
85 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
86 #define disc_timeout_jiff(s) \
87 	msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
88 #define root_path_confirmation_jiffies(s) \
89 	msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
90 
91 enum mpath_frame_type {
92 	MPATH_PREQ = 0,
93 	MPATH_PREP,
94 	MPATH_PERR,
95 	MPATH_RANN
96 };
97 
98 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
99 
mesh_path_sel_frame_tx(enum mpath_frame_type action,u8 flags,const u8 * orig_addr,u32 orig_sn,u8 target_flags,const u8 * target,u32 target_sn,const u8 * da,u8 hop_count,u8 ttl,u32 lifetime,u32 metric,u32 preq_id,struct ieee80211_sub_if_data * sdata)100 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
101 				  const u8 *orig_addr, u32 orig_sn,
102 				  u8 target_flags, const u8 *target,
103 				  u32 target_sn, const u8 *da,
104 				  u8 hop_count, u8 ttl,
105 				  u32 lifetime, u32 metric, u32 preq_id,
106 				  struct ieee80211_sub_if_data *sdata)
107 {
108 	struct ieee80211_local *local = sdata->local;
109 	struct sk_buff *skb;
110 	struct ieee80211_mgmt *mgmt;
111 	u8 *pos, ie_len;
112 	int hdr_len = offsetofend(struct ieee80211_mgmt,
113 				  u.action.u.mesh_action);
114 
115 	skb = dev_alloc_skb(local->tx_headroom +
116 			    hdr_len +
117 			    2 + 37); /* max HWMP IE */
118 	if (!skb)
119 		return -1;
120 	skb_reserve(skb, local->tx_headroom);
121 	mgmt = skb_put_zero(skb, hdr_len);
122 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
123 					  IEEE80211_STYPE_ACTION);
124 
125 	memcpy(mgmt->da, da, ETH_ALEN);
126 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
127 	/* BSSID == SA */
128 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
129 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
130 	mgmt->u.action.u.mesh_action.action_code =
131 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
132 
133 	switch (action) {
134 	case MPATH_PREQ:
135 		mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
136 		ie_len = 37;
137 		pos = skb_put(skb, 2 + ie_len);
138 		*pos++ = WLAN_EID_PREQ;
139 		break;
140 	case MPATH_PREP:
141 		mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
142 		ie_len = 31;
143 		pos = skb_put(skb, 2 + ie_len);
144 		*pos++ = WLAN_EID_PREP;
145 		break;
146 	case MPATH_RANN:
147 		mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
148 		ie_len = sizeof(struct ieee80211_rann_ie);
149 		pos = skb_put(skb, 2 + ie_len);
150 		*pos++ = WLAN_EID_RANN;
151 		break;
152 	default:
153 		kfree_skb(skb);
154 		return -ENOTSUPP;
155 	}
156 	*pos++ = ie_len;
157 	*pos++ = flags;
158 	*pos++ = hop_count;
159 	*pos++ = ttl;
160 	if (action == MPATH_PREP) {
161 		memcpy(pos, target, ETH_ALEN);
162 		pos += ETH_ALEN;
163 		put_unaligned_le32(target_sn, pos);
164 		pos += 4;
165 	} else {
166 		if (action == MPATH_PREQ) {
167 			put_unaligned_le32(preq_id, pos);
168 			pos += 4;
169 		}
170 		memcpy(pos, orig_addr, ETH_ALEN);
171 		pos += ETH_ALEN;
172 		put_unaligned_le32(orig_sn, pos);
173 		pos += 4;
174 	}
175 	put_unaligned_le32(lifetime, pos); /* interval for RANN */
176 	pos += 4;
177 	put_unaligned_le32(metric, pos);
178 	pos += 4;
179 	if (action == MPATH_PREQ) {
180 		*pos++ = 1; /* destination count */
181 		*pos++ = target_flags;
182 		memcpy(pos, target, ETH_ALEN);
183 		pos += ETH_ALEN;
184 		put_unaligned_le32(target_sn, pos);
185 		pos += 4;
186 	} else if (action == MPATH_PREP) {
187 		memcpy(pos, orig_addr, ETH_ALEN);
188 		pos += ETH_ALEN;
189 		put_unaligned_le32(orig_sn, pos);
190 		pos += 4;
191 	}
192 
193 	ieee80211_tx_skb(sdata, skb);
194 	return 0;
195 }
196 
197 
198 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
199  *  headroom in case the frame is encrypted. */
prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)200 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
201 		struct sk_buff *skb)
202 {
203 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
204 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
205 
206 	skb_reset_mac_header(skb);
207 	skb_reset_network_header(skb);
208 	skb_reset_transport_header(skb);
209 
210 	/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
211 	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
212 	skb->priority = 7;
213 
214 	info->control.vif = &sdata->vif;
215 	info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
216 	ieee80211_set_qos_hdr(sdata, skb);
217 	ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
218 }
219 
220 /**
221  * mesh_path_error_tx - Sends a PERR mesh management frame
222  *
223  * @ttl: allowed remaining hops
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  * @sdata: local mesh subif
229  *
230  * Note: This function may be called with driver locks taken that the driver
231  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
232  * frame directly but add it to the pending queue instead.
233  */
mesh_path_error_tx(struct ieee80211_sub_if_data * sdata,u8 ttl,const u8 * target,u32 target_sn,u16 target_rcode,const u8 * ra)234 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
235 		       u8 ttl, const u8 *target, u32 target_sn,
236 		       u16 target_rcode, const u8 *ra)
237 {
238 	struct ieee80211_local *local = sdata->local;
239 	struct sk_buff *skb;
240 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
241 	struct ieee80211_mgmt *mgmt;
242 	u8 *pos, ie_len;
243 	int hdr_len = offsetofend(struct ieee80211_mgmt,
244 				  u.action.u.mesh_action);
245 
246 	if (time_before(jiffies, ifmsh->next_perr))
247 		return -EAGAIN;
248 
249 	skb = dev_alloc_skb(local->tx_headroom +
250 			    IEEE80211_ENCRYPT_HEADROOM +
251 			    IEEE80211_ENCRYPT_TAILROOM +
252 			    hdr_len +
253 			    2 + 15 /* PERR IE */);
254 	if (!skb)
255 		return -1;
256 	skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
257 	mgmt = skb_put_zero(skb, hdr_len);
258 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
259 					  IEEE80211_STYPE_ACTION);
260 
261 	memcpy(mgmt->da, ra, ETH_ALEN);
262 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
263 	/* BSSID == SA */
264 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
265 	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
266 	mgmt->u.action.u.mesh_action.action_code =
267 					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
268 	ie_len = 15;
269 	pos = skb_put(skb, 2 + ie_len);
270 	*pos++ = WLAN_EID_PERR;
271 	*pos++ = ie_len;
272 	/* ttl */
273 	*pos++ = ttl;
274 	/* number of destinations */
275 	*pos++ = 1;
276 	/* Flags field has AE bit only as defined in
277 	 * sec 8.4.2.117 IEEE802.11-2012
278 	 */
279 	*pos = 0;
280 	pos++;
281 	memcpy(pos, target, ETH_ALEN);
282 	pos += ETH_ALEN;
283 	put_unaligned_le32(target_sn, pos);
284 	pos += 4;
285 	put_unaligned_le16(target_rcode, pos);
286 
287 	/* see note in function header */
288 	prepare_frame_for_deferred_tx(sdata, skb);
289 	ifmsh->next_perr = TU_TO_EXP_TIME(
290 				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
291 	ieee80211_add_pending_skb(local, skb);
292 	return 0;
293 }
294 
ieee80211s_update_metric(struct ieee80211_local * local,struct sta_info * sta,struct ieee80211_tx_status * st)295 void ieee80211s_update_metric(struct ieee80211_local *local,
296 			      struct sta_info *sta,
297 			      struct ieee80211_tx_status *st)
298 {
299 	struct ieee80211_tx_info *txinfo = st->info;
300 	int failed;
301 	struct rate_info rinfo;
302 
303 	failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
304 
305 	/* moving average, scaled to 100.
306 	 * feed failure as 100 and success as 0
307 	 */
308 	ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
309 	if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
310 			LINK_FAIL_THRESH)
311 		mesh_plink_broken(sta);
312 
313 	/* use rate info set by the driver directly if present */
314 	if (st->n_rates)
315 		rinfo = sta->deflink.tx_stats.last_rate_info;
316 	else
317 		sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
318 
319 	ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
320 				  cfg80211_calculate_bitrate(&rinfo));
321 }
322 
airtime_link_metric_get(struct ieee80211_local * local,struct sta_info * sta)323 u32 airtime_link_metric_get(struct ieee80211_local *local,
324 			    struct sta_info *sta)
325 {
326 	/* This should be adjusted for each device */
327 	int device_constant = 1 << ARITH_SHIFT;
328 	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
329 	int s_unit = 1 << ARITH_SHIFT;
330 	int rate, err;
331 	u32 tx_time, estimated_retx;
332 	u64 result;
333 	unsigned long fail_avg =
334 		ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
335 
336 	if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
337 		return MAX_METRIC;
338 
339 	/* Try to get rate based on HW/SW RC algorithm.
340 	 * Rate is returned in units of Kbps, correct this
341 	 * to comply with airtime calculation units
342 	 * Round up in case we get rate < 100Kbps
343 	 */
344 	rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
345 
346 	if (rate) {
347 		err = 0;
348 	} else {
349 		if (fail_avg > LINK_FAIL_THRESH)
350 			return MAX_METRIC;
351 
352 		rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
353 		if (WARN_ON(!rate))
354 			return MAX_METRIC;
355 
356 		err = (fail_avg << ARITH_SHIFT) / 100;
357 	}
358 
359 	/* bitrate is in units of 100 Kbps, while we need rate in units of
360 	 * 1Mbps. This will be corrected on tx_time computation.
361 	 */
362 	tx_time = (device_constant + 10 * test_frame_len / rate);
363 	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
364 	result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
365 	return (u32)result;
366 }
367 
368 /**
369  * hwmp_route_info_get - Update routing info to originator and transmitter
370  *
371  * @sdata: local mesh subif
372  * @mgmt: mesh management frame
373  * @hwmp_ie: hwmp information element (PREP or PREQ)
374  * @action: type of hwmp ie
375  *
376  * This function updates the path routing information to the originator and the
377  * transmitter of a HWMP PREQ or PREP frame.
378  *
379  * Returns: metric to frame originator or 0 if the frame should not be further
380  * processed
381  *
382  * Notes: this function is the only place (besides user-provided info) where
383  * path routing information is updated.
384  */
hwmp_route_info_get(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * hwmp_ie,enum mpath_frame_type action)385 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
386 			       struct ieee80211_mgmt *mgmt,
387 			       const u8 *hwmp_ie, enum mpath_frame_type action)
388 {
389 	struct ieee80211_local *local = sdata->local;
390 	struct mesh_path *mpath;
391 	struct sta_info *sta;
392 	bool fresh_info;
393 	const u8 *orig_addr, *ta;
394 	u32 orig_sn, orig_metric;
395 	unsigned long orig_lifetime, exp_time;
396 	u32 last_hop_metric, new_metric;
397 	bool process = true;
398 	u8 hopcount;
399 
400 	rcu_read_lock();
401 	sta = sta_info_get(sdata, mgmt->sa);
402 	if (!sta) {
403 		rcu_read_unlock();
404 		return 0;
405 	}
406 
407 	last_hop_metric = airtime_link_metric_get(local, sta);
408 	/* Update and check originator routing info */
409 	fresh_info = true;
410 
411 	switch (action) {
412 	case MPATH_PREQ:
413 		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
414 		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
415 		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
416 		orig_metric = PREQ_IE_METRIC(hwmp_ie);
417 		hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
418 		break;
419 	case MPATH_PREP:
420 		/* Originator here refers to the MP that was the target in the
421 		 * Path Request. We divert from the nomenclature in the draft
422 		 * so that we can easily use a single function to gather path
423 		 * information from both PREQ and PREP frames.
424 		 */
425 		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
426 		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
427 		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
428 		orig_metric = PREP_IE_METRIC(hwmp_ie);
429 		hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
430 		break;
431 	default:
432 		rcu_read_unlock();
433 		return 0;
434 	}
435 	new_metric = orig_metric + last_hop_metric;
436 	if (new_metric < orig_metric)
437 		new_metric = MAX_METRIC;
438 	exp_time = TU_TO_EXP_TIME(orig_lifetime);
439 
440 	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
441 		/* This MP is the originator, we are not interested in this
442 		 * frame, except for updating transmitter's path info.
443 		 */
444 		process = false;
445 		fresh_info = false;
446 	} else {
447 		mpath = mesh_path_lookup(sdata, orig_addr);
448 		if (mpath) {
449 			spin_lock_bh(&mpath->state_lock);
450 			if (mpath->flags & MESH_PATH_FIXED)
451 				fresh_info = false;
452 			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
453 			    (mpath->flags & MESH_PATH_SN_VALID)) {
454 				if (SN_GT(mpath->sn, orig_sn) ||
455 				    (mpath->sn == orig_sn &&
456 				     (rcu_access_pointer(mpath->next_hop) !=
457 						      sta ?
458 					      mult_frac(new_metric, 10, 9) :
459 					      new_metric) >= mpath->metric)) {
460 					process = false;
461 					fresh_info = false;
462 				}
463 			} else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
464 				bool have_sn, newer_sn, bounced;
465 
466 				have_sn = mpath->flags & MESH_PATH_SN_VALID;
467 				newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
468 				bounced = have_sn &&
469 					  (SN_DELTA(orig_sn, mpath->sn) >
470 							MAX_SANE_SN_DELTA);
471 
472 				if (!have_sn || newer_sn) {
473 					/* if SN is newer than what we had
474 					 * then we can take it */;
475 				} else if (bounced) {
476 					/* if SN is way different than what
477 					 * we had then assume the other side
478 					 * rebooted or restarted */;
479 				} else {
480 					process = false;
481 					fresh_info = false;
482 				}
483 			}
484 		} else {
485 			mpath = mesh_path_add(sdata, orig_addr);
486 			if (IS_ERR(mpath)) {
487 				rcu_read_unlock();
488 				return 0;
489 			}
490 			spin_lock_bh(&mpath->state_lock);
491 		}
492 
493 		if (fresh_info) {
494 			if (rcu_access_pointer(mpath->next_hop) != sta)
495 				mpath->path_change_count++;
496 			mesh_path_assign_nexthop(mpath, sta);
497 			mpath->flags |= MESH_PATH_SN_VALID;
498 			mpath->metric = new_metric;
499 			mpath->sn = orig_sn;
500 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
501 					  ?  mpath->exp_time : exp_time;
502 			mpath->hop_count = hopcount;
503 			mesh_path_activate(mpath);
504 			spin_unlock_bh(&mpath->state_lock);
505 			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
506 			/* init it at a low value - 0 start is tricky */
507 			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
508 			mesh_path_tx_pending(mpath);
509 			/* draft says preq_id should be saved to, but there does
510 			 * not seem to be any use for it, skipping by now
511 			 */
512 		} else
513 			spin_unlock_bh(&mpath->state_lock);
514 	}
515 
516 	/* Update and check transmitter routing info */
517 	ta = mgmt->sa;
518 	if (ether_addr_equal(orig_addr, ta))
519 		fresh_info = false;
520 	else {
521 		fresh_info = true;
522 
523 		mpath = mesh_path_lookup(sdata, ta);
524 		if (mpath) {
525 			spin_lock_bh(&mpath->state_lock);
526 			if ((mpath->flags & MESH_PATH_FIXED) ||
527 			    ((mpath->flags & MESH_PATH_ACTIVE) &&
528 			     ((rcu_access_pointer(mpath->next_hop) != sta ?
529 				       mult_frac(last_hop_metric, 10, 9) :
530 				       last_hop_metric) > mpath->metric)))
531 				fresh_info = false;
532 		} else {
533 			mpath = mesh_path_add(sdata, ta);
534 			if (IS_ERR(mpath)) {
535 				rcu_read_unlock();
536 				return 0;
537 			}
538 			spin_lock_bh(&mpath->state_lock);
539 		}
540 
541 		if (fresh_info) {
542 			if (rcu_access_pointer(mpath->next_hop) != sta)
543 				mpath->path_change_count++;
544 			mesh_path_assign_nexthop(mpath, sta);
545 			mpath->metric = last_hop_metric;
546 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
547 					  ?  mpath->exp_time : exp_time;
548 			mpath->hop_count = 1;
549 			mesh_path_activate(mpath);
550 			spin_unlock_bh(&mpath->state_lock);
551 			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
552 			/* init it at a low value - 0 start is tricky */
553 			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
554 			mesh_path_tx_pending(mpath);
555 		} else
556 			spin_unlock_bh(&mpath->state_lock);
557 	}
558 
559 	rcu_read_unlock();
560 
561 	return process ? new_metric : 0;
562 }
563 
hwmp_preq_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * preq_elem,u32 orig_metric)564 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
565 				    struct ieee80211_mgmt *mgmt,
566 				    const u8 *preq_elem, u32 orig_metric)
567 {
568 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
569 	struct mesh_path *mpath = NULL;
570 	const u8 *target_addr, *orig_addr;
571 	const u8 *da;
572 	u8 target_flags, ttl, flags;
573 	u32 orig_sn, target_sn, lifetime, target_metric = 0;
574 	bool reply = false;
575 	bool forward = true;
576 	bool root_is_gate;
577 
578 	/* Update target SN, if present */
579 	target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
580 	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
581 	target_sn = PREQ_IE_TARGET_SN(preq_elem);
582 	orig_sn = PREQ_IE_ORIG_SN(preq_elem);
583 	target_flags = PREQ_IE_TARGET_F(preq_elem);
584 	/* Proactive PREQ gate announcements */
585 	flags = PREQ_IE_FLAGS(preq_elem);
586 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
587 
588 	mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
589 
590 	if (ether_addr_equal(target_addr, sdata->vif.addr)) {
591 		mhwmp_dbg(sdata, "PREQ is for us\n");
592 		forward = false;
593 		reply = true;
594 		target_metric = 0;
595 
596 		if (SN_GT(target_sn, ifmsh->sn))
597 			ifmsh->sn = target_sn;
598 
599 		if (time_after(jiffies, ifmsh->last_sn_update +
600 					net_traversal_jiffies(sdata)) ||
601 		    time_before(jiffies, ifmsh->last_sn_update)) {
602 			++ifmsh->sn;
603 			ifmsh->last_sn_update = jiffies;
604 		}
605 		target_sn = ifmsh->sn;
606 	} else if (is_broadcast_ether_addr(target_addr) &&
607 		   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
608 		rcu_read_lock();
609 		mpath = mesh_path_lookup(sdata, orig_addr);
610 		if (mpath) {
611 			if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
612 				reply = true;
613 				target_addr = sdata->vif.addr;
614 				target_sn = ++ifmsh->sn;
615 				target_metric = 0;
616 				ifmsh->last_sn_update = jiffies;
617 			}
618 			if (root_is_gate)
619 				mesh_path_add_gate(mpath);
620 		}
621 		rcu_read_unlock();
622 	} else {
623 		rcu_read_lock();
624 		mpath = mesh_path_lookup(sdata, target_addr);
625 		if (mpath) {
626 			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
627 					SN_LT(mpath->sn, target_sn)) {
628 				mpath->sn = target_sn;
629 				mpath->flags |= MESH_PATH_SN_VALID;
630 			} else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
631 					(mpath->flags & MESH_PATH_ACTIVE)) {
632 				reply = true;
633 				target_metric = mpath->metric;
634 				target_sn = mpath->sn;
635 				/* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
636 				target_flags |= IEEE80211_PREQ_TO_FLAG;
637 			}
638 		}
639 		rcu_read_unlock();
640 	}
641 
642 	if (reply) {
643 		lifetime = PREQ_IE_LIFETIME(preq_elem);
644 		ttl = ifmsh->mshcfg.element_ttl;
645 		if (ttl != 0) {
646 			mhwmp_dbg(sdata, "replying to the PREQ\n");
647 			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
648 					       orig_sn, 0, target_addr,
649 					       target_sn, mgmt->sa, 0, ttl,
650 					       lifetime, target_metric, 0,
651 					       sdata);
652 		} else {
653 			ifmsh->mshstats.dropped_frames_ttl++;
654 		}
655 	}
656 
657 	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
658 		u32 preq_id;
659 		u8 hopcount;
660 
661 		ttl = PREQ_IE_TTL(preq_elem);
662 		lifetime = PREQ_IE_LIFETIME(preq_elem);
663 		if (ttl <= 1) {
664 			ifmsh->mshstats.dropped_frames_ttl++;
665 			return;
666 		}
667 		mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
668 		--ttl;
669 		preq_id = PREQ_IE_PREQ_ID(preq_elem);
670 		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
671 		da = (mpath && mpath->is_root) ?
672 			mpath->rann_snd_addr : broadcast_addr;
673 
674 		if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
675 			target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
676 			target_sn = PREQ_IE_TARGET_SN(preq_elem);
677 		}
678 
679 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
680 				       orig_sn, target_flags, target_addr,
681 				       target_sn, da, hopcount, ttl, lifetime,
682 				       orig_metric, preq_id, sdata);
683 		if (!is_multicast_ether_addr(da))
684 			ifmsh->mshstats.fwded_unicast++;
685 		else
686 			ifmsh->mshstats.fwded_mcast++;
687 		ifmsh->mshstats.fwded_frames++;
688 	}
689 }
690 
691 
692 static inline struct sta_info *
next_hop_deref_protected(struct mesh_path * mpath)693 next_hop_deref_protected(struct mesh_path *mpath)
694 {
695 	return rcu_dereference_protected(mpath->next_hop,
696 					 lockdep_is_held(&mpath->state_lock));
697 }
698 
699 
hwmp_prep_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * prep_elem,u32 metric)700 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
701 				    struct ieee80211_mgmt *mgmt,
702 				    const u8 *prep_elem, u32 metric)
703 {
704 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
705 	struct mesh_path *mpath;
706 	const u8 *target_addr, *orig_addr;
707 	u8 ttl, hopcount, flags;
708 	u8 next_hop[ETH_ALEN];
709 	u32 target_sn, orig_sn, lifetime;
710 
711 	mhwmp_dbg(sdata, "received PREP from %pM\n",
712 		  PREP_IE_TARGET_ADDR(prep_elem));
713 
714 	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
715 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
716 		/* destination, no forwarding required */
717 		return;
718 
719 	if (!ifmsh->mshcfg.dot11MeshForwarding)
720 		return;
721 
722 	ttl = PREP_IE_TTL(prep_elem);
723 	if (ttl <= 1) {
724 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
725 		return;
726 	}
727 
728 	rcu_read_lock();
729 	mpath = mesh_path_lookup(sdata, orig_addr);
730 	if (mpath)
731 		spin_lock_bh(&mpath->state_lock);
732 	else
733 		goto fail;
734 	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
735 		spin_unlock_bh(&mpath->state_lock);
736 		goto fail;
737 	}
738 	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
739 	spin_unlock_bh(&mpath->state_lock);
740 	--ttl;
741 	flags = PREP_IE_FLAGS(prep_elem);
742 	lifetime = PREP_IE_LIFETIME(prep_elem);
743 	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
744 	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
745 	target_sn = PREP_IE_TARGET_SN(prep_elem);
746 	orig_sn = PREP_IE_ORIG_SN(prep_elem);
747 
748 	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
749 			       target_addr, target_sn, next_hop, hopcount,
750 			       ttl, lifetime, metric, 0, sdata);
751 	rcu_read_unlock();
752 
753 	sdata->u.mesh.mshstats.fwded_unicast++;
754 	sdata->u.mesh.mshstats.fwded_frames++;
755 	return;
756 
757 fail:
758 	rcu_read_unlock();
759 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
760 }
761 
hwmp_perr_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * perr_elem)762 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
763 				    struct ieee80211_mgmt *mgmt,
764 				    const u8 *perr_elem)
765 {
766 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
767 	struct mesh_path *mpath;
768 	u8 ttl;
769 	const u8 *ta, *target_addr;
770 	u32 target_sn;
771 	u16 target_rcode;
772 
773 	ta = mgmt->sa;
774 	ttl = PERR_IE_TTL(perr_elem);
775 	if (ttl <= 1) {
776 		ifmsh->mshstats.dropped_frames_ttl++;
777 		return;
778 	}
779 	ttl--;
780 	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
781 	target_sn = PERR_IE_TARGET_SN(perr_elem);
782 	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
783 
784 	rcu_read_lock();
785 	mpath = mesh_path_lookup(sdata, target_addr);
786 	if (mpath) {
787 		struct sta_info *sta;
788 
789 		spin_lock_bh(&mpath->state_lock);
790 		sta = next_hop_deref_protected(mpath);
791 		if (mpath->flags & MESH_PATH_ACTIVE &&
792 		    ether_addr_equal(ta, sta->sta.addr) &&
793 		    !(mpath->flags & MESH_PATH_FIXED) &&
794 		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
795 		    SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
796 			mpath->flags &= ~MESH_PATH_ACTIVE;
797 			if (target_sn != 0)
798 				mpath->sn = target_sn;
799 			else
800 				mpath->sn += 1;
801 			spin_unlock_bh(&mpath->state_lock);
802 			if (!ifmsh->mshcfg.dot11MeshForwarding)
803 				goto endperr;
804 			mesh_path_error_tx(sdata, ttl, target_addr,
805 					   target_sn, target_rcode,
806 					   broadcast_addr);
807 		} else
808 			spin_unlock_bh(&mpath->state_lock);
809 	}
810 endperr:
811 	rcu_read_unlock();
812 }
813 
hwmp_rann_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const struct ieee80211_rann_ie * rann)814 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
815 				    struct ieee80211_mgmt *mgmt,
816 				    const struct ieee80211_rann_ie *rann)
817 {
818 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
819 	struct ieee80211_local *local = sdata->local;
820 	struct sta_info *sta;
821 	struct mesh_path *mpath;
822 	u8 ttl, flags, hopcount;
823 	const u8 *orig_addr;
824 	u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
825 	bool root_is_gate;
826 
827 	ttl = rann->rann_ttl;
828 	flags = rann->rann_flags;
829 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
830 	orig_addr = rann->rann_addr;
831 	orig_sn = le32_to_cpu(rann->rann_seq);
832 	interval = le32_to_cpu(rann->rann_interval);
833 	hopcount = rann->rann_hopcount;
834 	hopcount++;
835 	orig_metric = le32_to_cpu(rann->rann_metric);
836 
837 	/*  Ignore our own RANNs */
838 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
839 		return;
840 
841 	mhwmp_dbg(sdata,
842 		  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
843 		  orig_addr, mgmt->sa, root_is_gate);
844 
845 	rcu_read_lock();
846 	sta = sta_info_get(sdata, mgmt->sa);
847 	if (!sta) {
848 		rcu_read_unlock();
849 		return;
850 	}
851 
852 	last_hop_metric = airtime_link_metric_get(local, sta);
853 	new_metric = orig_metric + last_hop_metric;
854 	if (new_metric < orig_metric)
855 		new_metric = MAX_METRIC;
856 
857 	mpath = mesh_path_lookup(sdata, orig_addr);
858 	if (!mpath) {
859 		mpath = mesh_path_add(sdata, orig_addr);
860 		if (IS_ERR(mpath)) {
861 			rcu_read_unlock();
862 			sdata->u.mesh.mshstats.dropped_frames_no_route++;
863 			return;
864 		}
865 	}
866 
867 	if (!(SN_LT(mpath->sn, orig_sn)) &&
868 	    !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
869 		rcu_read_unlock();
870 		return;
871 	}
872 
873 	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
874 	     (time_after(jiffies, mpath->last_preq_to_root +
875 				  root_path_confirmation_jiffies(sdata)) ||
876 	     time_before(jiffies, mpath->last_preq_to_root))) &&
877 	     !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
878 		mhwmp_dbg(sdata,
879 			  "time to refresh root mpath %pM\n",
880 			  orig_addr);
881 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
882 		mpath->last_preq_to_root = jiffies;
883 	}
884 
885 	mpath->sn = orig_sn;
886 	mpath->rann_metric = new_metric;
887 	mpath->is_root = true;
888 	/* Recording RANNs sender address to send individually
889 	 * addressed PREQs destined for root mesh STA */
890 	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
891 
892 	if (root_is_gate)
893 		mesh_path_add_gate(mpath);
894 
895 	if (ttl <= 1) {
896 		ifmsh->mshstats.dropped_frames_ttl++;
897 		rcu_read_unlock();
898 		return;
899 	}
900 	ttl--;
901 
902 	if (ifmsh->mshcfg.dot11MeshForwarding) {
903 		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
904 				       orig_sn, 0, NULL, 0, broadcast_addr,
905 				       hopcount, ttl, interval,
906 				       new_metric, 0, sdata);
907 	}
908 
909 	rcu_read_unlock();
910 }
911 
912 
mesh_rx_path_sel_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len)913 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
914 			    struct ieee80211_mgmt *mgmt, size_t len)
915 {
916 	struct ieee802_11_elems *elems;
917 	size_t baselen;
918 	u32 path_metric;
919 	struct sta_info *sta;
920 
921 	/* need action_code */
922 	if (len < IEEE80211_MIN_ACTION_SIZE + 1)
923 		return;
924 
925 	rcu_read_lock();
926 	sta = sta_info_get(sdata, mgmt->sa);
927 	if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
928 		rcu_read_unlock();
929 		return;
930 	}
931 	rcu_read_unlock();
932 
933 	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
934 	elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
935 				       len - baselen, false, NULL);
936 	if (!elems)
937 		return;
938 
939 	if (elems->preq) {
940 		if (elems->preq_len != 37)
941 			/* Right now we support just 1 destination and no AE */
942 			goto free;
943 		path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
944 						  MPATH_PREQ);
945 		if (path_metric)
946 			hwmp_preq_frame_process(sdata, mgmt, elems->preq,
947 						path_metric);
948 	}
949 	if (elems->prep) {
950 		if (elems->prep_len != 31)
951 			/* Right now we support no AE */
952 			goto free;
953 		path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
954 						  MPATH_PREP);
955 		if (path_metric)
956 			hwmp_prep_frame_process(sdata, mgmt, elems->prep,
957 						path_metric);
958 	}
959 	if (elems->perr) {
960 		if (elems->perr_len != 15)
961 			/* Right now we support only one destination per PERR */
962 			goto free;
963 		hwmp_perr_frame_process(sdata, mgmt, elems->perr);
964 	}
965 	if (elems->rann)
966 		hwmp_rann_frame_process(sdata, mgmt, elems->rann);
967 free:
968 	kfree(elems);
969 }
970 
971 /**
972  * mesh_queue_preq - queue a PREQ to a given destination
973  *
974  * @mpath: mesh path to discover
975  * @flags: special attributes of the PREQ to be sent
976  *
977  * Locking: the function must be called from within a rcu read lock block.
978  *
979  */
mesh_queue_preq(struct mesh_path * mpath,u8 flags)980 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
981 {
982 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
983 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
984 	struct mesh_preq_queue *preq_node;
985 
986 	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
987 	if (!preq_node) {
988 		mhwmp_dbg(sdata, "could not allocate PREQ node\n");
989 		return;
990 	}
991 
992 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
993 	if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
994 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
995 		kfree(preq_node);
996 		if (printk_ratelimit())
997 			mhwmp_dbg(sdata, "PREQ node queue full\n");
998 		return;
999 	}
1000 
1001 	spin_lock(&mpath->state_lock);
1002 	if (mpath->flags & MESH_PATH_REQ_QUEUED) {
1003 		spin_unlock(&mpath->state_lock);
1004 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1005 		kfree(preq_node);
1006 		return;
1007 	}
1008 
1009 	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1010 	preq_node->flags = flags;
1011 
1012 	mpath->flags |= MESH_PATH_REQ_QUEUED;
1013 	spin_unlock(&mpath->state_lock);
1014 
1015 	list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1016 	++ifmsh->preq_queue_len;
1017 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1018 
1019 	if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1020 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1021 
1022 	else if (time_before(jiffies, ifmsh->last_preq)) {
1023 		/* avoid long wait if did not send preqs for a long time
1024 		 * and jiffies wrapped around
1025 		 */
1026 		ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1027 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1028 	} else
1029 		mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1030 						min_preq_int_jiff(sdata));
1031 }
1032 
1033 /**
1034  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1035  *
1036  * @sdata: local mesh subif
1037  */
mesh_path_start_discovery(struct ieee80211_sub_if_data * sdata)1038 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1039 {
1040 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1041 	struct mesh_preq_queue *preq_node;
1042 	struct mesh_path *mpath;
1043 	u8 ttl, target_flags = 0;
1044 	const u8 *da;
1045 	u32 lifetime;
1046 
1047 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1048 	if (!ifmsh->preq_queue_len ||
1049 		time_before(jiffies, ifmsh->last_preq +
1050 				min_preq_int_jiff(sdata))) {
1051 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1052 		return;
1053 	}
1054 
1055 	preq_node = list_first_entry(&ifmsh->preq_queue.list,
1056 			struct mesh_preq_queue, list);
1057 	list_del(&preq_node->list);
1058 	--ifmsh->preq_queue_len;
1059 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1060 
1061 	rcu_read_lock();
1062 	mpath = mesh_path_lookup(sdata, preq_node->dst);
1063 	if (!mpath)
1064 		goto enddiscovery;
1065 
1066 	spin_lock_bh(&mpath->state_lock);
1067 	if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1068 		spin_unlock_bh(&mpath->state_lock);
1069 		goto enddiscovery;
1070 	}
1071 	mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1072 	if (preq_node->flags & PREQ_Q_F_START) {
1073 		if (mpath->flags & MESH_PATH_RESOLVING) {
1074 			spin_unlock_bh(&mpath->state_lock);
1075 			goto enddiscovery;
1076 		} else {
1077 			mpath->flags &= ~MESH_PATH_RESOLVED;
1078 			mpath->flags |= MESH_PATH_RESOLVING;
1079 			mpath->discovery_retries = 0;
1080 			mpath->discovery_timeout = disc_timeout_jiff(sdata);
1081 		}
1082 	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1083 			mpath->flags & MESH_PATH_RESOLVED) {
1084 		mpath->flags &= ~MESH_PATH_RESOLVING;
1085 		spin_unlock_bh(&mpath->state_lock);
1086 		goto enddiscovery;
1087 	}
1088 
1089 	ifmsh->last_preq = jiffies;
1090 
1091 	if (time_after(jiffies, ifmsh->last_sn_update +
1092 				net_traversal_jiffies(sdata)) ||
1093 	    time_before(jiffies, ifmsh->last_sn_update)) {
1094 		++ifmsh->sn;
1095 		sdata->u.mesh.last_sn_update = jiffies;
1096 	}
1097 	lifetime = default_lifetime(sdata);
1098 	ttl = sdata->u.mesh.mshcfg.element_ttl;
1099 	if (ttl == 0) {
1100 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
1101 		spin_unlock_bh(&mpath->state_lock);
1102 		goto enddiscovery;
1103 	}
1104 
1105 	if (preq_node->flags & PREQ_Q_F_REFRESH)
1106 		target_flags |= IEEE80211_PREQ_TO_FLAG;
1107 	else
1108 		target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1109 
1110 	spin_unlock_bh(&mpath->state_lock);
1111 	da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1112 	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1113 			       target_flags, mpath->dst, mpath->sn, da, 0,
1114 			       ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1115 
1116 	spin_lock_bh(&mpath->state_lock);
1117 	if (!(mpath->flags & MESH_PATH_DELETED))
1118 		mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1119 	spin_unlock_bh(&mpath->state_lock);
1120 
1121 enddiscovery:
1122 	rcu_read_unlock();
1123 	kfree(preq_node);
1124 }
1125 
1126 /**
1127  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1128  *
1129  * @skb: 802.11 frame to be sent
1130  * @sdata: network subif the frame will be sent through
1131  *
1132  * Lookup next hop for given skb and start path discovery if no
1133  * forwarding information is found.
1134  *
1135  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1136  * skb is freed here if no mpath could be allocated.
1137  */
mesh_nexthop_resolve(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1138 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1139 			 struct sk_buff *skb)
1140 {
1141 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1142 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1143 	struct mesh_path *mpath;
1144 	struct sk_buff *skb_to_free = NULL;
1145 	u8 *target_addr = hdr->addr3;
1146 
1147 	/* Nulls are only sent to peers for PS and should be pre-addressed */
1148 	if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1149 		return 0;
1150 
1151 	/* Allow injected packets to bypass mesh routing */
1152 	if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1153 		return 0;
1154 
1155 	if (!mesh_nexthop_lookup(sdata, skb))
1156 		return 0;
1157 
1158 	/* no nexthop found, start resolving */
1159 	mpath = mesh_path_lookup(sdata, target_addr);
1160 	if (!mpath) {
1161 		mpath = mesh_path_add(sdata, target_addr);
1162 		if (IS_ERR(mpath)) {
1163 			mesh_path_discard_frame(sdata, skb);
1164 			return PTR_ERR(mpath);
1165 		}
1166 	}
1167 
1168 	if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1169 	    mesh_path_sel_is_hwmp(sdata))
1170 		mesh_queue_preq(mpath, PREQ_Q_F_START);
1171 
1172 	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1173 		skb_to_free = skb_dequeue(&mpath->frame_queue);
1174 
1175 	info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1176 	ieee80211_set_qos_hdr(sdata, skb);
1177 	skb_queue_tail(&mpath->frame_queue, skb);
1178 	if (skb_to_free)
1179 		mesh_path_discard_frame(sdata, skb_to_free);
1180 
1181 	return -ENOENT;
1182 }
1183 
1184 /**
1185  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1186  * @skb: 802.11 frame to be sent
1187  * @sdata: network subif the frame will be sent through
1188  *
1189  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1190  * And if so, set the RA (addr1) to it to transmit to this node directly,
1191  * avoiding PREQ/PREP path discovery.
1192  *
1193  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1194  */
mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1195 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1196 				       struct sk_buff *skb)
1197 {
1198 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1199 	struct sta_info *sta;
1200 
1201 	if (is_multicast_ether_addr(hdr->addr1))
1202 		return -ENOENT;
1203 
1204 	rcu_read_lock();
1205 	sta = sta_info_get(sdata, hdr->addr3);
1206 
1207 	if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1208 		rcu_read_unlock();
1209 		return -ENOENT;
1210 	}
1211 	rcu_read_unlock();
1212 
1213 	memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1214 	memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1215 	return 0;
1216 }
1217 
1218 /**
1219  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1220  * this function is considered "using" the associated mpath, so preempt a path
1221  * refresh if this mpath expires soon.
1222  *
1223  * @skb: 802.11 frame to be sent
1224  * @sdata: network subif the frame will be sent through
1225  *
1226  * Returns: 0 if the next hop was found. Nonzero otherwise.
1227  */
mesh_nexthop_lookup(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1228 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1229 			struct sk_buff *skb)
1230 {
1231 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1232 	struct mesh_path *mpath;
1233 	struct sta_info *next_hop;
1234 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1235 	u8 *target_addr = hdr->addr3;
1236 
1237 	if (ifmsh->mshcfg.dot11MeshNolearn &&
1238 	    !mesh_nexthop_lookup_nolearn(sdata, skb))
1239 		return 0;
1240 
1241 	mpath = mesh_path_lookup(sdata, target_addr);
1242 	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1243 		return -ENOENT;
1244 
1245 	if (time_after(jiffies,
1246 		       mpath->exp_time -
1247 		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1248 	    ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1249 	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1250 	    !(mpath->flags & MESH_PATH_FIXED))
1251 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1252 
1253 	next_hop = rcu_dereference(mpath->next_hop);
1254 	if (next_hop) {
1255 		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1256 		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1257 		ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1258 		return 0;
1259 	}
1260 
1261 	return -ENOENT;
1262 }
1263 
mesh_path_timer(struct timer_list * t)1264 void mesh_path_timer(struct timer_list *t)
1265 {
1266 	struct mesh_path *mpath = from_timer(mpath, t, timer);
1267 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1268 	int ret;
1269 
1270 	if (sdata->local->quiescing)
1271 		return;
1272 
1273 	spin_lock_bh(&mpath->state_lock);
1274 	if (mpath->flags & MESH_PATH_RESOLVED ||
1275 			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1276 		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1277 		spin_unlock_bh(&mpath->state_lock);
1278 	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1279 		++mpath->discovery_retries;
1280 		mpath->discovery_timeout *= 2;
1281 		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1282 		spin_unlock_bh(&mpath->state_lock);
1283 		mesh_queue_preq(mpath, 0);
1284 	} else {
1285 		mpath->flags &= ~(MESH_PATH_RESOLVING |
1286 				  MESH_PATH_RESOLVED |
1287 				  MESH_PATH_REQ_QUEUED);
1288 		mpath->exp_time = jiffies;
1289 		spin_unlock_bh(&mpath->state_lock);
1290 		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1291 			ret = mesh_path_send_to_gates(mpath);
1292 			if (ret)
1293 				mhwmp_dbg(sdata, "no gate was reachable\n");
1294 		} else
1295 			mesh_path_flush_pending(mpath);
1296 	}
1297 }
1298 
mesh_path_tx_root_frame(struct ieee80211_sub_if_data * sdata)1299 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1300 {
1301 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1302 	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1303 	u8 flags, target_flags = 0;
1304 
1305 	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1306 			? RANN_FLAG_IS_GATE : 0;
1307 
1308 	switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1309 	case IEEE80211_PROACTIVE_RANN:
1310 		mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1311 				       ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1312 				       0, ifmsh->mshcfg.element_ttl,
1313 				       interval, 0, 0, sdata);
1314 		break;
1315 	case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1316 		flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1317 		fallthrough;
1318 	case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1319 		interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1320 		target_flags |= IEEE80211_PREQ_TO_FLAG |
1321 				IEEE80211_PREQ_USN_FLAG;
1322 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1323 				       ++ifmsh->sn, target_flags,
1324 				       (u8 *) broadcast_addr, 0, broadcast_addr,
1325 				       0, ifmsh->mshcfg.element_ttl, interval,
1326 				       0, ifmsh->preq_id++, sdata);
1327 		break;
1328 	default:
1329 		mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1330 		return;
1331 	}
1332 }
1333