1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Copyright (C) 2019, 2021 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 			    sdata->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 + sdata->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 	sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
314 	ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
315 				  cfg80211_calculate_bitrate(&rinfo));
316 }
317 
airtime_link_metric_get(struct ieee80211_local * local,struct sta_info * sta)318 u32 airtime_link_metric_get(struct ieee80211_local *local,
319 			    struct sta_info *sta)
320 {
321 	/* This should be adjusted for each device */
322 	int device_constant = 1 << ARITH_SHIFT;
323 	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
324 	int s_unit = 1 << ARITH_SHIFT;
325 	int rate, err;
326 	u32 tx_time, estimated_retx;
327 	u64 result;
328 	unsigned long fail_avg =
329 		ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
330 
331 	if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
332 		return MAX_METRIC;
333 
334 	/* Try to get rate based on HW/SW RC algorithm.
335 	 * Rate is returned in units of Kbps, correct this
336 	 * to comply with airtime calculation units
337 	 * Round up in case we get rate < 100Kbps
338 	 */
339 	rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
340 
341 	if (rate) {
342 		err = 0;
343 	} else {
344 		if (fail_avg > LINK_FAIL_THRESH)
345 			return MAX_METRIC;
346 
347 		rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
348 		if (WARN_ON(!rate))
349 			return MAX_METRIC;
350 
351 		err = (fail_avg << ARITH_SHIFT) / 100;
352 	}
353 
354 	/* bitrate is in units of 100 Kbps, while we need rate in units of
355 	 * 1Mbps. This will be corrected on tx_time computation.
356 	 */
357 	tx_time = (device_constant + 10 * test_frame_len / rate);
358 	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
359 	result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
360 	return (u32)result;
361 }
362 
363 /**
364  * hwmp_route_info_get - Update routing info to originator and transmitter
365  *
366  * @sdata: local mesh subif
367  * @mgmt: mesh management frame
368  * @hwmp_ie: hwmp information element (PREP or PREQ)
369  * @action: type of hwmp ie
370  *
371  * This function updates the path routing information to the originator and the
372  * transmitter of a HWMP PREQ or PREP frame.
373  *
374  * Returns: metric to frame originator or 0 if the frame should not be further
375  * processed
376  *
377  * Notes: this function is the only place (besides user-provided info) where
378  * path routing information is updated.
379  */
hwmp_route_info_get(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * hwmp_ie,enum mpath_frame_type action)380 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
381 			       struct ieee80211_mgmt *mgmt,
382 			       const u8 *hwmp_ie, enum mpath_frame_type action)
383 {
384 	struct ieee80211_local *local = sdata->local;
385 	struct mesh_path *mpath;
386 	struct sta_info *sta;
387 	bool fresh_info;
388 	const u8 *orig_addr, *ta;
389 	u32 orig_sn, orig_metric;
390 	unsigned long orig_lifetime, exp_time;
391 	u32 last_hop_metric, new_metric;
392 	bool process = true;
393 	u8 hopcount;
394 
395 	rcu_read_lock();
396 	sta = sta_info_get(sdata, mgmt->sa);
397 	if (!sta) {
398 		rcu_read_unlock();
399 		return 0;
400 	}
401 
402 	last_hop_metric = airtime_link_metric_get(local, sta);
403 	/* Update and check originator routing info */
404 	fresh_info = true;
405 
406 	switch (action) {
407 	case MPATH_PREQ:
408 		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
409 		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
410 		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
411 		orig_metric = PREQ_IE_METRIC(hwmp_ie);
412 		hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
413 		break;
414 	case MPATH_PREP:
415 		/* Originator here refers to the MP that was the target in the
416 		 * Path Request. We divert from the nomenclature in the draft
417 		 * so that we can easily use a single function to gather path
418 		 * information from both PREQ and PREP frames.
419 		 */
420 		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
421 		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
422 		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
423 		orig_metric = PREP_IE_METRIC(hwmp_ie);
424 		hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
425 		break;
426 	default:
427 		rcu_read_unlock();
428 		return 0;
429 	}
430 	new_metric = orig_metric + last_hop_metric;
431 	if (new_metric < orig_metric)
432 		new_metric = MAX_METRIC;
433 	exp_time = TU_TO_EXP_TIME(orig_lifetime);
434 
435 	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
436 		/* This MP is the originator, we are not interested in this
437 		 * frame, except for updating transmitter's path info.
438 		 */
439 		process = false;
440 		fresh_info = false;
441 	} else {
442 		mpath = mesh_path_lookup(sdata, orig_addr);
443 		if (mpath) {
444 			spin_lock_bh(&mpath->state_lock);
445 			if (mpath->flags & MESH_PATH_FIXED)
446 				fresh_info = false;
447 			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
448 			    (mpath->flags & MESH_PATH_SN_VALID)) {
449 				if (SN_GT(mpath->sn, orig_sn) ||
450 				    (mpath->sn == orig_sn &&
451 				     (rcu_access_pointer(mpath->next_hop) !=
452 						      sta ?
453 					      mult_frac(new_metric, 10, 9) :
454 					      new_metric) >= mpath->metric)) {
455 					process = false;
456 					fresh_info = false;
457 				}
458 			} else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
459 				bool have_sn, newer_sn, bounced;
460 
461 				have_sn = mpath->flags & MESH_PATH_SN_VALID;
462 				newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
463 				bounced = have_sn &&
464 					  (SN_DELTA(orig_sn, mpath->sn) >
465 							MAX_SANE_SN_DELTA);
466 
467 				if (!have_sn || newer_sn) {
468 					/* if SN is newer than what we had
469 					 * then we can take it */;
470 				} else if (bounced) {
471 					/* if SN is way different than what
472 					 * we had then assume the other side
473 					 * rebooted or restarted */;
474 				} else {
475 					process = false;
476 					fresh_info = false;
477 				}
478 			}
479 		} else {
480 			mpath = mesh_path_add(sdata, orig_addr);
481 			if (IS_ERR(mpath)) {
482 				rcu_read_unlock();
483 				return 0;
484 			}
485 			spin_lock_bh(&mpath->state_lock);
486 		}
487 
488 		if (fresh_info) {
489 			if (rcu_access_pointer(mpath->next_hop) != sta)
490 				mpath->path_change_count++;
491 			mesh_path_assign_nexthop(mpath, sta);
492 			mpath->flags |= MESH_PATH_SN_VALID;
493 			mpath->metric = new_metric;
494 			mpath->sn = orig_sn;
495 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
496 					  ?  mpath->exp_time : exp_time;
497 			mpath->hop_count = hopcount;
498 			mesh_path_activate(mpath);
499 			spin_unlock_bh(&mpath->state_lock);
500 			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
501 			/* init it at a low value - 0 start is tricky */
502 			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
503 			mesh_path_tx_pending(mpath);
504 			/* draft says preq_id should be saved to, but there does
505 			 * not seem to be any use for it, skipping by now
506 			 */
507 		} else
508 			spin_unlock_bh(&mpath->state_lock);
509 	}
510 
511 	/* Update and check transmitter routing info */
512 	ta = mgmt->sa;
513 	if (ether_addr_equal(orig_addr, ta))
514 		fresh_info = false;
515 	else {
516 		fresh_info = true;
517 
518 		mpath = mesh_path_lookup(sdata, ta);
519 		if (mpath) {
520 			spin_lock_bh(&mpath->state_lock);
521 			if ((mpath->flags & MESH_PATH_FIXED) ||
522 			    ((mpath->flags & MESH_PATH_ACTIVE) &&
523 			     ((rcu_access_pointer(mpath->next_hop) != sta ?
524 				       mult_frac(last_hop_metric, 10, 9) :
525 				       last_hop_metric) > mpath->metric)))
526 				fresh_info = false;
527 		} else {
528 			mpath = mesh_path_add(sdata, ta);
529 			if (IS_ERR(mpath)) {
530 				rcu_read_unlock();
531 				return 0;
532 			}
533 			spin_lock_bh(&mpath->state_lock);
534 		}
535 
536 		if (fresh_info) {
537 			if (rcu_access_pointer(mpath->next_hop) != sta)
538 				mpath->path_change_count++;
539 			mesh_path_assign_nexthop(mpath, sta);
540 			mpath->metric = last_hop_metric;
541 			mpath->exp_time = time_after(mpath->exp_time, exp_time)
542 					  ?  mpath->exp_time : exp_time;
543 			mpath->hop_count = 1;
544 			mesh_path_activate(mpath);
545 			spin_unlock_bh(&mpath->state_lock);
546 			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
547 			/* init it at a low value - 0 start is tricky */
548 			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
549 			mesh_path_tx_pending(mpath);
550 		} else
551 			spin_unlock_bh(&mpath->state_lock);
552 	}
553 
554 	rcu_read_unlock();
555 
556 	return process ? new_metric : 0;
557 }
558 
hwmp_preq_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * preq_elem,u32 orig_metric)559 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
560 				    struct ieee80211_mgmt *mgmt,
561 				    const u8 *preq_elem, u32 orig_metric)
562 {
563 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
564 	struct mesh_path *mpath = NULL;
565 	const u8 *target_addr, *orig_addr;
566 	const u8 *da;
567 	u8 target_flags, ttl, flags;
568 	u32 orig_sn, target_sn, lifetime, target_metric = 0;
569 	bool reply = false;
570 	bool forward = true;
571 	bool root_is_gate;
572 
573 	/* Update target SN, if present */
574 	target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
575 	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
576 	target_sn = PREQ_IE_TARGET_SN(preq_elem);
577 	orig_sn = PREQ_IE_ORIG_SN(preq_elem);
578 	target_flags = PREQ_IE_TARGET_F(preq_elem);
579 	/* Proactive PREQ gate announcements */
580 	flags = PREQ_IE_FLAGS(preq_elem);
581 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
582 
583 	mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
584 
585 	if (ether_addr_equal(target_addr, sdata->vif.addr)) {
586 		mhwmp_dbg(sdata, "PREQ is for us\n");
587 		forward = false;
588 		reply = true;
589 		target_metric = 0;
590 
591 		if (SN_GT(target_sn, ifmsh->sn))
592 			ifmsh->sn = target_sn;
593 
594 		if (time_after(jiffies, ifmsh->last_sn_update +
595 					net_traversal_jiffies(sdata)) ||
596 		    time_before(jiffies, ifmsh->last_sn_update)) {
597 			++ifmsh->sn;
598 			ifmsh->last_sn_update = jiffies;
599 		}
600 		target_sn = ifmsh->sn;
601 	} else if (is_broadcast_ether_addr(target_addr) &&
602 		   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
603 		rcu_read_lock();
604 		mpath = mesh_path_lookup(sdata, orig_addr);
605 		if (mpath) {
606 			if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
607 				reply = true;
608 				target_addr = sdata->vif.addr;
609 				target_sn = ++ifmsh->sn;
610 				target_metric = 0;
611 				ifmsh->last_sn_update = jiffies;
612 			}
613 			if (root_is_gate)
614 				mesh_path_add_gate(mpath);
615 		}
616 		rcu_read_unlock();
617 	} else {
618 		rcu_read_lock();
619 		mpath = mesh_path_lookup(sdata, target_addr);
620 		if (mpath) {
621 			if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
622 					SN_LT(mpath->sn, target_sn)) {
623 				mpath->sn = target_sn;
624 				mpath->flags |= MESH_PATH_SN_VALID;
625 			} else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
626 					(mpath->flags & MESH_PATH_ACTIVE)) {
627 				reply = true;
628 				target_metric = mpath->metric;
629 				target_sn = mpath->sn;
630 				/* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
631 				target_flags |= IEEE80211_PREQ_TO_FLAG;
632 			}
633 		}
634 		rcu_read_unlock();
635 	}
636 
637 	if (reply) {
638 		lifetime = PREQ_IE_LIFETIME(preq_elem);
639 		ttl = ifmsh->mshcfg.element_ttl;
640 		if (ttl != 0) {
641 			mhwmp_dbg(sdata, "replying to the PREQ\n");
642 			mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
643 					       orig_sn, 0, target_addr,
644 					       target_sn, mgmt->sa, 0, ttl,
645 					       lifetime, target_metric, 0,
646 					       sdata);
647 		} else {
648 			ifmsh->mshstats.dropped_frames_ttl++;
649 		}
650 	}
651 
652 	if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
653 		u32 preq_id;
654 		u8 hopcount;
655 
656 		ttl = PREQ_IE_TTL(preq_elem);
657 		lifetime = PREQ_IE_LIFETIME(preq_elem);
658 		if (ttl <= 1) {
659 			ifmsh->mshstats.dropped_frames_ttl++;
660 			return;
661 		}
662 		mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
663 		--ttl;
664 		preq_id = PREQ_IE_PREQ_ID(preq_elem);
665 		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
666 		da = (mpath && mpath->is_root) ?
667 			mpath->rann_snd_addr : broadcast_addr;
668 
669 		if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
670 			target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
671 			target_sn = PREQ_IE_TARGET_SN(preq_elem);
672 		}
673 
674 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
675 				       orig_sn, target_flags, target_addr,
676 				       target_sn, da, hopcount, ttl, lifetime,
677 				       orig_metric, preq_id, sdata);
678 		if (!is_multicast_ether_addr(da))
679 			ifmsh->mshstats.fwded_unicast++;
680 		else
681 			ifmsh->mshstats.fwded_mcast++;
682 		ifmsh->mshstats.fwded_frames++;
683 	}
684 }
685 
686 
687 static inline struct sta_info *
next_hop_deref_protected(struct mesh_path * mpath)688 next_hop_deref_protected(struct mesh_path *mpath)
689 {
690 	return rcu_dereference_protected(mpath->next_hop,
691 					 lockdep_is_held(&mpath->state_lock));
692 }
693 
694 
hwmp_prep_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * prep_elem,u32 metric)695 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
696 				    struct ieee80211_mgmt *mgmt,
697 				    const u8 *prep_elem, u32 metric)
698 {
699 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
700 	struct mesh_path *mpath;
701 	const u8 *target_addr, *orig_addr;
702 	u8 ttl, hopcount, flags;
703 	u8 next_hop[ETH_ALEN];
704 	u32 target_sn, orig_sn, lifetime;
705 
706 	mhwmp_dbg(sdata, "received PREP from %pM\n",
707 		  PREP_IE_TARGET_ADDR(prep_elem));
708 
709 	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
710 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
711 		/* destination, no forwarding required */
712 		return;
713 
714 	if (!ifmsh->mshcfg.dot11MeshForwarding)
715 		return;
716 
717 	ttl = PREP_IE_TTL(prep_elem);
718 	if (ttl <= 1) {
719 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
720 		return;
721 	}
722 
723 	rcu_read_lock();
724 	mpath = mesh_path_lookup(sdata, orig_addr);
725 	if (mpath)
726 		spin_lock_bh(&mpath->state_lock);
727 	else
728 		goto fail;
729 	if (!(mpath->flags & MESH_PATH_ACTIVE)) {
730 		spin_unlock_bh(&mpath->state_lock);
731 		goto fail;
732 	}
733 	memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
734 	spin_unlock_bh(&mpath->state_lock);
735 	--ttl;
736 	flags = PREP_IE_FLAGS(prep_elem);
737 	lifetime = PREP_IE_LIFETIME(prep_elem);
738 	hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
739 	target_addr = PREP_IE_TARGET_ADDR(prep_elem);
740 	target_sn = PREP_IE_TARGET_SN(prep_elem);
741 	orig_sn = PREP_IE_ORIG_SN(prep_elem);
742 
743 	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
744 			       target_addr, target_sn, next_hop, hopcount,
745 			       ttl, lifetime, metric, 0, sdata);
746 	rcu_read_unlock();
747 
748 	sdata->u.mesh.mshstats.fwded_unicast++;
749 	sdata->u.mesh.mshstats.fwded_frames++;
750 	return;
751 
752 fail:
753 	rcu_read_unlock();
754 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
755 }
756 
hwmp_perr_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const u8 * perr_elem)757 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
758 				    struct ieee80211_mgmt *mgmt,
759 				    const u8 *perr_elem)
760 {
761 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
762 	struct mesh_path *mpath;
763 	u8 ttl;
764 	const u8 *ta, *target_addr;
765 	u32 target_sn;
766 	u16 target_rcode;
767 
768 	ta = mgmt->sa;
769 	ttl = PERR_IE_TTL(perr_elem);
770 	if (ttl <= 1) {
771 		ifmsh->mshstats.dropped_frames_ttl++;
772 		return;
773 	}
774 	ttl--;
775 	target_addr = PERR_IE_TARGET_ADDR(perr_elem);
776 	target_sn = PERR_IE_TARGET_SN(perr_elem);
777 	target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
778 
779 	rcu_read_lock();
780 	mpath = mesh_path_lookup(sdata, target_addr);
781 	if (mpath) {
782 		struct sta_info *sta;
783 
784 		spin_lock_bh(&mpath->state_lock);
785 		sta = next_hop_deref_protected(mpath);
786 		if (mpath->flags & MESH_PATH_ACTIVE &&
787 		    ether_addr_equal(ta, sta->sta.addr) &&
788 		    !(mpath->flags & MESH_PATH_FIXED) &&
789 		    (!(mpath->flags & MESH_PATH_SN_VALID) ||
790 		    SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
791 			mpath->flags &= ~MESH_PATH_ACTIVE;
792 			if (target_sn != 0)
793 				mpath->sn = target_sn;
794 			else
795 				mpath->sn += 1;
796 			spin_unlock_bh(&mpath->state_lock);
797 			if (!ifmsh->mshcfg.dot11MeshForwarding)
798 				goto endperr;
799 			mesh_path_error_tx(sdata, ttl, target_addr,
800 					   target_sn, target_rcode,
801 					   broadcast_addr);
802 		} else
803 			spin_unlock_bh(&mpath->state_lock);
804 	}
805 endperr:
806 	rcu_read_unlock();
807 }
808 
hwmp_rann_frame_process(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,const struct ieee80211_rann_ie * rann)809 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
810 				    struct ieee80211_mgmt *mgmt,
811 				    const struct ieee80211_rann_ie *rann)
812 {
813 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
814 	struct ieee80211_local *local = sdata->local;
815 	struct sta_info *sta;
816 	struct mesh_path *mpath;
817 	u8 ttl, flags, hopcount;
818 	const u8 *orig_addr;
819 	u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
820 	bool root_is_gate;
821 
822 	ttl = rann->rann_ttl;
823 	flags = rann->rann_flags;
824 	root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
825 	orig_addr = rann->rann_addr;
826 	orig_sn = le32_to_cpu(rann->rann_seq);
827 	interval = le32_to_cpu(rann->rann_interval);
828 	hopcount = rann->rann_hopcount;
829 	hopcount++;
830 	orig_metric = le32_to_cpu(rann->rann_metric);
831 
832 	/*  Ignore our own RANNs */
833 	if (ether_addr_equal(orig_addr, sdata->vif.addr))
834 		return;
835 
836 	mhwmp_dbg(sdata,
837 		  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
838 		  orig_addr, mgmt->sa, root_is_gate);
839 
840 	rcu_read_lock();
841 	sta = sta_info_get(sdata, mgmt->sa);
842 	if (!sta) {
843 		rcu_read_unlock();
844 		return;
845 	}
846 
847 	last_hop_metric = airtime_link_metric_get(local, sta);
848 	new_metric = orig_metric + last_hop_metric;
849 	if (new_metric < orig_metric)
850 		new_metric = MAX_METRIC;
851 
852 	mpath = mesh_path_lookup(sdata, orig_addr);
853 	if (!mpath) {
854 		mpath = mesh_path_add(sdata, orig_addr);
855 		if (IS_ERR(mpath)) {
856 			rcu_read_unlock();
857 			sdata->u.mesh.mshstats.dropped_frames_no_route++;
858 			return;
859 		}
860 	}
861 
862 	if (!(SN_LT(mpath->sn, orig_sn)) &&
863 	    !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
864 		rcu_read_unlock();
865 		return;
866 	}
867 
868 	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
869 	     (time_after(jiffies, mpath->last_preq_to_root +
870 				  root_path_confirmation_jiffies(sdata)) ||
871 	     time_before(jiffies, mpath->last_preq_to_root))) &&
872 	     !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
873 		mhwmp_dbg(sdata,
874 			  "time to refresh root mpath %pM\n",
875 			  orig_addr);
876 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
877 		mpath->last_preq_to_root = jiffies;
878 	}
879 
880 	mpath->sn = orig_sn;
881 	mpath->rann_metric = new_metric;
882 	mpath->is_root = true;
883 	/* Recording RANNs sender address to send individually
884 	 * addressed PREQs destined for root mesh STA */
885 	memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
886 
887 	if (root_is_gate)
888 		mesh_path_add_gate(mpath);
889 
890 	if (ttl <= 1) {
891 		ifmsh->mshstats.dropped_frames_ttl++;
892 		rcu_read_unlock();
893 		return;
894 	}
895 	ttl--;
896 
897 	if (ifmsh->mshcfg.dot11MeshForwarding) {
898 		mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
899 				       orig_sn, 0, NULL, 0, broadcast_addr,
900 				       hopcount, ttl, interval,
901 				       new_metric, 0, sdata);
902 	}
903 
904 	rcu_read_unlock();
905 }
906 
907 
mesh_rx_path_sel_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len)908 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
909 			    struct ieee80211_mgmt *mgmt, size_t len)
910 {
911 	struct ieee802_11_elems *elems;
912 	size_t baselen;
913 	u32 path_metric;
914 	struct sta_info *sta;
915 
916 	/* need action_code */
917 	if (len < IEEE80211_MIN_ACTION_SIZE + 1)
918 		return;
919 
920 	rcu_read_lock();
921 	sta = sta_info_get(sdata, mgmt->sa);
922 	if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
923 		rcu_read_unlock();
924 		return;
925 	}
926 	rcu_read_unlock();
927 
928 	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
929 	elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
930 				       len - baselen, false, mgmt->bssid, NULL);
931 	if (!elems)
932 		return;
933 
934 	if (elems->preq) {
935 		if (elems->preq_len != 37)
936 			/* Right now we support just 1 destination and no AE */
937 			goto free;
938 		path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
939 						  MPATH_PREQ);
940 		if (path_metric)
941 			hwmp_preq_frame_process(sdata, mgmt, elems->preq,
942 						path_metric);
943 	}
944 	if (elems->prep) {
945 		if (elems->prep_len != 31)
946 			/* Right now we support no AE */
947 			goto free;
948 		path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
949 						  MPATH_PREP);
950 		if (path_metric)
951 			hwmp_prep_frame_process(sdata, mgmt, elems->prep,
952 						path_metric);
953 	}
954 	if (elems->perr) {
955 		if (elems->perr_len != 15)
956 			/* Right now we support only one destination per PERR */
957 			goto free;
958 		hwmp_perr_frame_process(sdata, mgmt, elems->perr);
959 	}
960 	if (elems->rann)
961 		hwmp_rann_frame_process(sdata, mgmt, elems->rann);
962 free:
963 	kfree(elems);
964 }
965 
966 /**
967  * mesh_queue_preq - queue a PREQ to a given destination
968  *
969  * @mpath: mesh path to discover
970  * @flags: special attributes of the PREQ to be sent
971  *
972  * Locking: the function must be called from within a rcu read lock block.
973  *
974  */
mesh_queue_preq(struct mesh_path * mpath,u8 flags)975 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
976 {
977 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
978 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
979 	struct mesh_preq_queue *preq_node;
980 
981 	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
982 	if (!preq_node) {
983 		mhwmp_dbg(sdata, "could not allocate PREQ node\n");
984 		return;
985 	}
986 
987 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
988 	if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
989 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
990 		kfree(preq_node);
991 		if (printk_ratelimit())
992 			mhwmp_dbg(sdata, "PREQ node queue full\n");
993 		return;
994 	}
995 
996 	spin_lock(&mpath->state_lock);
997 	if (mpath->flags & MESH_PATH_REQ_QUEUED) {
998 		spin_unlock(&mpath->state_lock);
999 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1000 		kfree(preq_node);
1001 		return;
1002 	}
1003 
1004 	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1005 	preq_node->flags = flags;
1006 
1007 	mpath->flags |= MESH_PATH_REQ_QUEUED;
1008 	spin_unlock(&mpath->state_lock);
1009 
1010 	list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1011 	++ifmsh->preq_queue_len;
1012 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1013 
1014 	if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1015 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1016 
1017 	else if (time_before(jiffies, ifmsh->last_preq)) {
1018 		/* avoid long wait if did not send preqs for a long time
1019 		 * and jiffies wrapped around
1020 		 */
1021 		ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1022 		ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1023 	} else
1024 		mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1025 						min_preq_int_jiff(sdata));
1026 }
1027 
1028 /**
1029  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1030  *
1031  * @sdata: local mesh subif
1032  */
mesh_path_start_discovery(struct ieee80211_sub_if_data * sdata)1033 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1034 {
1035 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1036 	struct mesh_preq_queue *preq_node;
1037 	struct mesh_path *mpath;
1038 	u8 ttl, target_flags = 0;
1039 	const u8 *da;
1040 	u32 lifetime;
1041 
1042 	spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1043 	if (!ifmsh->preq_queue_len ||
1044 		time_before(jiffies, ifmsh->last_preq +
1045 				min_preq_int_jiff(sdata))) {
1046 		spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1047 		return;
1048 	}
1049 
1050 	preq_node = list_first_entry(&ifmsh->preq_queue.list,
1051 			struct mesh_preq_queue, list);
1052 	list_del(&preq_node->list);
1053 	--ifmsh->preq_queue_len;
1054 	spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1055 
1056 	rcu_read_lock();
1057 	mpath = mesh_path_lookup(sdata, preq_node->dst);
1058 	if (!mpath)
1059 		goto enddiscovery;
1060 
1061 	spin_lock_bh(&mpath->state_lock);
1062 	if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1063 		spin_unlock_bh(&mpath->state_lock);
1064 		goto enddiscovery;
1065 	}
1066 	mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1067 	if (preq_node->flags & PREQ_Q_F_START) {
1068 		if (mpath->flags & MESH_PATH_RESOLVING) {
1069 			spin_unlock_bh(&mpath->state_lock);
1070 			goto enddiscovery;
1071 		} else {
1072 			mpath->flags &= ~MESH_PATH_RESOLVED;
1073 			mpath->flags |= MESH_PATH_RESOLVING;
1074 			mpath->discovery_retries = 0;
1075 			mpath->discovery_timeout = disc_timeout_jiff(sdata);
1076 		}
1077 	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1078 			mpath->flags & MESH_PATH_RESOLVED) {
1079 		mpath->flags &= ~MESH_PATH_RESOLVING;
1080 		spin_unlock_bh(&mpath->state_lock);
1081 		goto enddiscovery;
1082 	}
1083 
1084 	ifmsh->last_preq = jiffies;
1085 
1086 	if (time_after(jiffies, ifmsh->last_sn_update +
1087 				net_traversal_jiffies(sdata)) ||
1088 	    time_before(jiffies, ifmsh->last_sn_update)) {
1089 		++ifmsh->sn;
1090 		sdata->u.mesh.last_sn_update = jiffies;
1091 	}
1092 	lifetime = default_lifetime(sdata);
1093 	ttl = sdata->u.mesh.mshcfg.element_ttl;
1094 	if (ttl == 0) {
1095 		sdata->u.mesh.mshstats.dropped_frames_ttl++;
1096 		spin_unlock_bh(&mpath->state_lock);
1097 		goto enddiscovery;
1098 	}
1099 
1100 	if (preq_node->flags & PREQ_Q_F_REFRESH)
1101 		target_flags |= IEEE80211_PREQ_TO_FLAG;
1102 	else
1103 		target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1104 
1105 	spin_unlock_bh(&mpath->state_lock);
1106 	da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1107 	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1108 			       target_flags, mpath->dst, mpath->sn, da, 0,
1109 			       ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1110 
1111 	spin_lock_bh(&mpath->state_lock);
1112 	if (!(mpath->flags & MESH_PATH_DELETED))
1113 		mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1114 	spin_unlock_bh(&mpath->state_lock);
1115 
1116 enddiscovery:
1117 	rcu_read_unlock();
1118 	kfree(preq_node);
1119 }
1120 
1121 /**
1122  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1123  *
1124  * @skb: 802.11 frame to be sent
1125  * @sdata: network subif the frame will be sent through
1126  *
1127  * Lookup next hop for given skb and start path discovery if no
1128  * forwarding information is found.
1129  *
1130  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1131  * skb is freed here if no mpath could be allocated.
1132  */
mesh_nexthop_resolve(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1133 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1134 			 struct sk_buff *skb)
1135 {
1136 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1137 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1138 	struct mesh_path *mpath;
1139 	struct sk_buff *skb_to_free = NULL;
1140 	u8 *target_addr = hdr->addr3;
1141 
1142 	/* Nulls are only sent to peers for PS and should be pre-addressed */
1143 	if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1144 		return 0;
1145 
1146 	/* Allow injected packets to bypass mesh routing */
1147 	if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1148 		return 0;
1149 
1150 	if (!mesh_nexthop_lookup(sdata, skb))
1151 		return 0;
1152 
1153 	/* no nexthop found, start resolving */
1154 	mpath = mesh_path_lookup(sdata, target_addr);
1155 	if (!mpath) {
1156 		mpath = mesh_path_add(sdata, target_addr);
1157 		if (IS_ERR(mpath)) {
1158 			mesh_path_discard_frame(sdata, skb);
1159 			return PTR_ERR(mpath);
1160 		}
1161 	}
1162 
1163 	if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1164 	    mesh_path_sel_is_hwmp(sdata))
1165 		mesh_queue_preq(mpath, PREQ_Q_F_START);
1166 
1167 	if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1168 		skb_to_free = skb_dequeue(&mpath->frame_queue);
1169 
1170 	info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1171 	ieee80211_set_qos_hdr(sdata, skb);
1172 	skb_queue_tail(&mpath->frame_queue, skb);
1173 	if (skb_to_free)
1174 		mesh_path_discard_frame(sdata, skb_to_free);
1175 
1176 	return -ENOENT;
1177 }
1178 
1179 /**
1180  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1181  * @skb: 802.11 frame to be sent
1182  * @sdata: network subif the frame will be sent through
1183  *
1184  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1185  * And if so, set the RA (addr1) to it to transmit to this node directly,
1186  * avoiding PREQ/PREP path discovery.
1187  *
1188  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1189  */
mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1190 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1191 				       struct sk_buff *skb)
1192 {
1193 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1194 	struct sta_info *sta;
1195 
1196 	if (is_multicast_ether_addr(hdr->addr1))
1197 		return -ENOENT;
1198 
1199 	rcu_read_lock();
1200 	sta = sta_info_get(sdata, hdr->addr3);
1201 
1202 	if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1203 		rcu_read_unlock();
1204 		return -ENOENT;
1205 	}
1206 	rcu_read_unlock();
1207 
1208 	memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1209 	memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1210 	return 0;
1211 }
1212 
1213 /**
1214  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1215  * this function is considered "using" the associated mpath, so preempt a path
1216  * refresh if this mpath expires soon.
1217  *
1218  * @skb: 802.11 frame to be sent
1219  * @sdata: network subif the frame will be sent through
1220  *
1221  * Returns: 0 if the next hop was found. Nonzero otherwise.
1222  */
mesh_nexthop_lookup(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)1223 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1224 			struct sk_buff *skb)
1225 {
1226 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1227 	struct mesh_path *mpath;
1228 	struct sta_info *next_hop;
1229 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1230 	u8 *target_addr = hdr->addr3;
1231 
1232 	if (ifmsh->mshcfg.dot11MeshNolearn &&
1233 	    !mesh_nexthop_lookup_nolearn(sdata, skb))
1234 		return 0;
1235 
1236 	mpath = mesh_path_lookup(sdata, target_addr);
1237 	if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1238 		return -ENOENT;
1239 
1240 	if (time_after(jiffies,
1241 		       mpath->exp_time -
1242 		       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1243 	    ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1244 	    !(mpath->flags & MESH_PATH_RESOLVING) &&
1245 	    !(mpath->flags & MESH_PATH_FIXED))
1246 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1247 
1248 	next_hop = rcu_dereference(mpath->next_hop);
1249 	if (next_hop) {
1250 		memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1251 		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1252 		ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1253 		return 0;
1254 	}
1255 
1256 	return -ENOENT;
1257 }
1258 
mesh_path_timer(struct timer_list * t)1259 void mesh_path_timer(struct timer_list *t)
1260 {
1261 	struct mesh_path *mpath = from_timer(mpath, t, timer);
1262 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
1263 	int ret;
1264 
1265 	if (sdata->local->quiescing)
1266 		return;
1267 
1268 	spin_lock_bh(&mpath->state_lock);
1269 	if (mpath->flags & MESH_PATH_RESOLVED ||
1270 			(!(mpath->flags & MESH_PATH_RESOLVING))) {
1271 		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1272 		spin_unlock_bh(&mpath->state_lock);
1273 	} else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1274 		++mpath->discovery_retries;
1275 		mpath->discovery_timeout *= 2;
1276 		mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1277 		spin_unlock_bh(&mpath->state_lock);
1278 		mesh_queue_preq(mpath, 0);
1279 	} else {
1280 		mpath->flags &= ~(MESH_PATH_RESOLVING |
1281 				  MESH_PATH_RESOLVED |
1282 				  MESH_PATH_REQ_QUEUED);
1283 		mpath->exp_time = jiffies;
1284 		spin_unlock_bh(&mpath->state_lock);
1285 		if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1286 			ret = mesh_path_send_to_gates(mpath);
1287 			if (ret)
1288 				mhwmp_dbg(sdata, "no gate was reachable\n");
1289 		} else
1290 			mesh_path_flush_pending(mpath);
1291 	}
1292 }
1293 
mesh_path_tx_root_frame(struct ieee80211_sub_if_data * sdata)1294 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1295 {
1296 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1297 	u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1298 	u8 flags, target_flags = 0;
1299 
1300 	flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1301 			? RANN_FLAG_IS_GATE : 0;
1302 
1303 	switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1304 	case IEEE80211_PROACTIVE_RANN:
1305 		mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1306 				       ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1307 				       0, ifmsh->mshcfg.element_ttl,
1308 				       interval, 0, 0, sdata);
1309 		break;
1310 	case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1311 		flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1312 		fallthrough;
1313 	case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1314 		interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1315 		target_flags |= IEEE80211_PREQ_TO_FLAG |
1316 				IEEE80211_PREQ_USN_FLAG;
1317 		mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1318 				       ++ifmsh->sn, target_flags,
1319 				       (u8 *) broadcast_addr, 0, broadcast_addr,
1320 				       0, ifmsh->mshcfg.element_ttl, interval,
1321 				       0, ifmsh->preq_id++, sdata);
1322 		break;
1323 	default:
1324 		mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1325 		return;
1326 	}
1327 }
1328