GNU Linux-libre 4.14.266-gnu1
[releases.git] / net / mac80211 / mesh_hwmp.c
1 /*
2  * Copyright (c) 2008, 2009 open80211s Ltd.
3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9
10 #include <linux/slab.h>
11 #include <linux/etherdevice.h>
12 #include <asm/unaligned.h>
13 #include "wme.h"
14 #include "mesh.h"
15
16 #define TEST_FRAME_LEN  8192
17 #define MAX_METRIC      0xffffffff
18 #define ARITH_SHIFT     8
19 #define LINK_FAIL_THRESH 95
20
21 #define MAX_PREQ_QUEUE_LEN      64
22
23 static void mesh_queue_preq(struct mesh_path *, u8);
24
25 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
26 {
27         if (ae)
28                 offset += 6;
29         return get_unaligned_le32(preq_elem + offset);
30 }
31
32 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
33 {
34         if (ae)
35                 offset += 6;
36         return get_unaligned_le16(preq_elem + offset);
37 }
38
39 /* HWMP IE processing macros */
40 #define AE_F                    (1<<6)
41 #define AE_F_SET(x)             (*x & AE_F)
42 #define PREQ_IE_FLAGS(x)        (*(x))
43 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
44 #define PREQ_IE_TTL(x)          (*(x + 2))
45 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
46 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
47 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
48 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
49 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
50 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
51 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
52 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
53
54
55 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
56 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
57 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
58 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
59 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
60 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
61 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
62 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
63 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
64
65 #define PERR_IE_TTL(x)          (*(x))
66 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
67 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
68 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
69 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
70
71 #define MSEC_TO_TU(x) (x*1000/1024)
72 #define SN_GT(x, y) ((s32)(y - x) < 0)
73 #define SN_LT(x, y) ((s32)(x - y) < 0)
74 #define MAX_SANE_SN_DELTA 32
75
76 static inline u32 SN_DELTA(u32 x, u32 y)
77 {
78         return x >= y ? x - y : y - x;
79 }
80
81 #define net_traversal_jiffies(s) \
82         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
83 #define default_lifetime(s) \
84         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
85 #define min_preq_int_jiff(s) \
86         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
87 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
88 #define disc_timeout_jiff(s) \
89         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
90 #define root_path_confirmation_jiffies(s) \
91         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
92
93 enum mpath_frame_type {
94         MPATH_PREQ = 0,
95         MPATH_PREP,
96         MPATH_PERR,
97         MPATH_RANN
98 };
99
100 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
101
102 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
103                                   const u8 *orig_addr, u32 orig_sn,
104                                   u8 target_flags, const u8 *target,
105                                   u32 target_sn, const u8 *da,
106                                   u8 hop_count, u8 ttl,
107                                   u32 lifetime, u32 metric, u32 preq_id,
108                                   struct ieee80211_sub_if_data *sdata)
109 {
110         struct ieee80211_local *local = sdata->local;
111         struct sk_buff *skb;
112         struct ieee80211_mgmt *mgmt;
113         u8 *pos, ie_len;
114         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
115                       sizeof(mgmt->u.action.u.mesh_action);
116
117         skb = dev_alloc_skb(local->tx_headroom +
118                             hdr_len +
119                             2 + 37); /* max HWMP IE */
120         if (!skb)
121                 return -1;
122         skb_reserve(skb, local->tx_headroom);
123         mgmt = skb_put_zero(skb, hdr_len);
124         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
125                                           IEEE80211_STYPE_ACTION);
126
127         memcpy(mgmt->da, da, ETH_ALEN);
128         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
129         /* BSSID == SA */
130         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
131         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
132         mgmt->u.action.u.mesh_action.action_code =
133                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
134
135         switch (action) {
136         case MPATH_PREQ:
137                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
138                 ie_len = 37;
139                 pos = skb_put(skb, 2 + ie_len);
140                 *pos++ = WLAN_EID_PREQ;
141                 break;
142         case MPATH_PREP:
143                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
144                 ie_len = 31;
145                 pos = skb_put(skb, 2 + ie_len);
146                 *pos++ = WLAN_EID_PREP;
147                 break;
148         case MPATH_RANN:
149                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
150                 ie_len = sizeof(struct ieee80211_rann_ie);
151                 pos = skb_put(skb, 2 + ie_len);
152                 *pos++ = WLAN_EID_RANN;
153                 break;
154         default:
155                 kfree_skb(skb);
156                 return -ENOTSUPP;
157         }
158         *pos++ = ie_len;
159         *pos++ = flags;
160         *pos++ = hop_count;
161         *pos++ = ttl;
162         if (action == MPATH_PREP) {
163                 memcpy(pos, target, ETH_ALEN);
164                 pos += ETH_ALEN;
165                 put_unaligned_le32(target_sn, pos);
166                 pos += 4;
167         } else {
168                 if (action == MPATH_PREQ) {
169                         put_unaligned_le32(preq_id, pos);
170                         pos += 4;
171                 }
172                 memcpy(pos, orig_addr, ETH_ALEN);
173                 pos += ETH_ALEN;
174                 put_unaligned_le32(orig_sn, pos);
175                 pos += 4;
176         }
177         put_unaligned_le32(lifetime, pos); /* interval for RANN */
178         pos += 4;
179         put_unaligned_le32(metric, pos);
180         pos += 4;
181         if (action == MPATH_PREQ) {
182                 *pos++ = 1; /* destination count */
183                 *pos++ = target_flags;
184                 memcpy(pos, target, ETH_ALEN);
185                 pos += ETH_ALEN;
186                 put_unaligned_le32(target_sn, pos);
187                 pos += 4;
188         } else if (action == MPATH_PREP) {
189                 memcpy(pos, orig_addr, ETH_ALEN);
190                 pos += ETH_ALEN;
191                 put_unaligned_le32(orig_sn, pos);
192                 pos += 4;
193         }
194
195         ieee80211_tx_skb(sdata, skb);
196         return 0;
197 }
198
199
200 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
201  *  headroom in case the frame is encrypted. */
202 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
203                 struct sk_buff *skb)
204 {
205         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
206         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
207
208         skb_reset_mac_header(skb);
209         skb_reset_network_header(skb);
210         skb_reset_transport_header(skb);
211
212         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
213         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
214         skb->priority = 7;
215
216         info->control.vif = &sdata->vif;
217         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
218         ieee80211_set_qos_hdr(sdata, skb);
219         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
220 }
221
222 /**
223  * mesh_path_error_tx - Sends a PERR mesh management frame
224  *
225  * @ttl: allowed remaining hops
226  * @target: broken destination
227  * @target_sn: SN of the broken destination
228  * @target_rcode: reason code for this PERR
229  * @ra: node this frame is addressed to
230  * @sdata: local mesh subif
231  *
232  * Note: This function may be called with driver locks taken that the driver
233  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
234  * frame directly but add it to the pending queue instead.
235  */
236 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
237                        u8 ttl, const u8 *target, u32 target_sn,
238                        u16 target_rcode, const u8 *ra)
239 {
240         struct ieee80211_local *local = sdata->local;
241         struct sk_buff *skb;
242         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
243         struct ieee80211_mgmt *mgmt;
244         u8 *pos, ie_len;
245         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
246                       sizeof(mgmt->u.action.u.mesh_action);
247
248         if (time_before(jiffies, ifmsh->next_perr))
249                 return -EAGAIN;
250
251         skb = dev_alloc_skb(local->tx_headroom +
252                             sdata->encrypt_headroom +
253                             IEEE80211_ENCRYPT_TAILROOM +
254                             hdr_len +
255                             2 + 15 /* PERR IE */);
256         if (!skb)
257                 return -1;
258         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
259         mgmt = skb_put_zero(skb, hdr_len);
260         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
261                                           IEEE80211_STYPE_ACTION);
262
263         memcpy(mgmt->da, ra, ETH_ALEN);
264         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
265         /* BSSID == SA */
266         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
267         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
268         mgmt->u.action.u.mesh_action.action_code =
269                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
270         ie_len = 15;
271         pos = skb_put(skb, 2 + ie_len);
272         *pos++ = WLAN_EID_PERR;
273         *pos++ = ie_len;
274         /* ttl */
275         *pos++ = ttl;
276         /* number of destinations */
277         *pos++ = 1;
278         /* Flags field has AE bit only as defined in
279          * sec 8.4.2.117 IEEE802.11-2012
280          */
281         *pos = 0;
282         pos++;
283         memcpy(pos, target, ETH_ALEN);
284         pos += ETH_ALEN;
285         put_unaligned_le32(target_sn, pos);
286         pos += 4;
287         put_unaligned_le16(target_rcode, pos);
288
289         /* see note in function header */
290         prepare_frame_for_deferred_tx(sdata, skb);
291         ifmsh->next_perr = TU_TO_EXP_TIME(
292                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
293         ieee80211_add_pending_skb(local, skb);
294         return 0;
295 }
296
297 void ieee80211s_update_metric(struct ieee80211_local *local,
298                               struct sta_info *sta,
299                               struct ieee80211_tx_status *st)
300 {
301         struct ieee80211_tx_info *txinfo = st->info;
302         int failed;
303
304         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
305
306         /* moving average, scaled to 100.
307          * feed failure as 100 and success as 0
308          */
309         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
310         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
311                         LINK_FAIL_THRESH)
312                 mesh_plink_broken(sta);
313 }
314
315 static u32 airtime_link_metric_get(struct ieee80211_local *local,
316                                    struct sta_info *sta)
317 {
318         struct rate_info rinfo;
319         /* This should be adjusted for each device */
320         int device_constant = 1 << ARITH_SHIFT;
321         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
322         int s_unit = 1 << ARITH_SHIFT;
323         int rate, err;
324         u32 tx_time, estimated_retx;
325         u64 result;
326         unsigned long fail_avg =
327                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
328
329         if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
330                 return MAX_METRIC;
331
332         /* Try to get rate based on HW/SW RC algorithm.
333          * Rate is returned in units of Kbps, correct this
334          * to comply with airtime calculation units
335          * Round up in case we get rate < 100Kbps
336          */
337         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
338
339         if (rate) {
340                 err = 0;
341         } else {
342                 if (fail_avg > LINK_FAIL_THRESH)
343                         return MAX_METRIC;
344
345                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
346                 rate = cfg80211_calculate_bitrate(&rinfo);
347                 if (WARN_ON(!rate))
348                         return MAX_METRIC;
349
350                 err = (fail_avg << ARITH_SHIFT) / 100;
351         }
352
353         /* bitrate is in units of 100 Kbps, while we need rate in units of
354          * 1Mbps. This will be corrected on tx_time computation.
355          */
356         tx_time = (device_constant + 10 * test_frame_len / rate);
357         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
358         result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
359         return (u32)result;
360 }
361
362 /**
363  * hwmp_route_info_get - Update routing info to originator and transmitter
364  *
365  * @sdata: local mesh subif
366  * @mgmt: mesh management frame
367  * @hwmp_ie: hwmp information element (PREP or PREQ)
368  * @action: type of hwmp ie
369  *
370  * This function updates the path routing information to the originator and the
371  * transmitter of a HWMP PREQ or PREP frame.
372  *
373  * Returns: metric to frame originator or 0 if the frame should not be further
374  * processed
375  *
376  * Notes: this function is the only place (besides user-provided info) where
377  * path routing information is updated.
378  */
379 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
380                                struct ieee80211_mgmt *mgmt,
381                                const u8 *hwmp_ie, enum mpath_frame_type action)
382 {
383         struct ieee80211_local *local = sdata->local;
384         struct mesh_path *mpath;
385         struct sta_info *sta;
386         bool fresh_info;
387         const u8 *orig_addr, *ta;
388         u32 orig_sn, orig_metric;
389         unsigned long orig_lifetime, exp_time;
390         u32 last_hop_metric, new_metric;
391         bool process = true;
392
393         rcu_read_lock();
394         sta = sta_info_get(sdata, mgmt->sa);
395         if (!sta) {
396                 rcu_read_unlock();
397                 return 0;
398         }
399
400         last_hop_metric = airtime_link_metric_get(local, sta);
401         /* Update and check originator routing info */
402         fresh_info = true;
403
404         switch (action) {
405         case MPATH_PREQ:
406                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
407                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
408                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
409                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
410                 break;
411         case MPATH_PREP:
412                 /* Originator here refers to the MP that was the target in the
413                  * Path Request. We divert from the nomenclature in the draft
414                  * so that we can easily use a single function to gather path
415                  * information from both PREQ and PREP frames.
416                  */
417                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
418                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
419                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
420                 orig_metric = PREP_IE_METRIC(hwmp_ie);
421                 break;
422         default:
423                 rcu_read_unlock();
424                 return 0;
425         }
426         new_metric = orig_metric + last_hop_metric;
427         if (new_metric < orig_metric)
428                 new_metric = MAX_METRIC;
429         exp_time = TU_TO_EXP_TIME(orig_lifetime);
430
431         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
432                 /* This MP is the originator, we are not interested in this
433                  * frame, except for updating transmitter's path info.
434                  */
435                 process = false;
436                 fresh_info = false;
437         } else {
438                 mpath = mesh_path_lookup(sdata, orig_addr);
439                 if (mpath) {
440                         spin_lock_bh(&mpath->state_lock);
441                         if (mpath->flags & MESH_PATH_FIXED)
442                                 fresh_info = false;
443                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
444                             (mpath->flags & MESH_PATH_SN_VALID)) {
445                                 if (SN_GT(mpath->sn, orig_sn) ||
446                                     (mpath->sn == orig_sn &&
447                                      new_metric >= mpath->metric)) {
448                                         process = false;
449                                         fresh_info = false;
450                                 }
451                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
452                                 bool have_sn, newer_sn, bounced;
453
454                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
455                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
456                                 bounced = have_sn &&
457                                           (SN_DELTA(orig_sn, mpath->sn) >
458                                                         MAX_SANE_SN_DELTA);
459
460                                 if (!have_sn || newer_sn) {
461                                         /* if SN is newer than what we had
462                                          * then we can take it */;
463                                 } else if (bounced) {
464                                         /* if SN is way different than what
465                                          * we had then assume the other side
466                                          * rebooted or restarted */;
467                                 } else {
468                                         process = false;
469                                         fresh_info = false;
470                                 }
471                         }
472                 } else {
473                         mpath = mesh_path_add(sdata, orig_addr);
474                         if (IS_ERR(mpath)) {
475                                 rcu_read_unlock();
476                                 return 0;
477                         }
478                         spin_lock_bh(&mpath->state_lock);
479                 }
480
481                 if (fresh_info) {
482                         mesh_path_assign_nexthop(mpath, sta);
483                         mpath->flags |= MESH_PATH_SN_VALID;
484                         mpath->metric = new_metric;
485                         mpath->sn = orig_sn;
486                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
487                                           ?  mpath->exp_time : exp_time;
488                         mesh_path_activate(mpath);
489                         spin_unlock_bh(&mpath->state_lock);
490                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
491                         /* init it at a low value - 0 start is tricky */
492                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
493                         mesh_path_tx_pending(mpath);
494                         /* draft says preq_id should be saved to, but there does
495                          * not seem to be any use for it, skipping by now
496                          */
497                 } else
498                         spin_unlock_bh(&mpath->state_lock);
499         }
500
501         /* Update and check transmitter routing info */
502         ta = mgmt->sa;
503         if (ether_addr_equal(orig_addr, ta))
504                 fresh_info = false;
505         else {
506                 fresh_info = true;
507
508                 mpath = mesh_path_lookup(sdata, ta);
509                 if (mpath) {
510                         spin_lock_bh(&mpath->state_lock);
511                         if ((mpath->flags & MESH_PATH_FIXED) ||
512                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
513                                         (last_hop_metric > mpath->metric)))
514                                 fresh_info = false;
515                 } else {
516                         mpath = mesh_path_add(sdata, ta);
517                         if (IS_ERR(mpath)) {
518                                 rcu_read_unlock();
519                                 return 0;
520                         }
521                         spin_lock_bh(&mpath->state_lock);
522                 }
523
524                 if (fresh_info) {
525                         mesh_path_assign_nexthop(mpath, sta);
526                         mpath->metric = last_hop_metric;
527                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
528                                           ?  mpath->exp_time : exp_time;
529                         mesh_path_activate(mpath);
530                         spin_unlock_bh(&mpath->state_lock);
531                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
532                         /* init it at a low value - 0 start is tricky */
533                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
534                         mesh_path_tx_pending(mpath);
535                 } else
536                         spin_unlock_bh(&mpath->state_lock);
537         }
538
539         rcu_read_unlock();
540
541         return process ? new_metric : 0;
542 }
543
544 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
545                                     struct ieee80211_mgmt *mgmt,
546                                     const u8 *preq_elem, u32 orig_metric)
547 {
548         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
549         struct mesh_path *mpath = NULL;
550         const u8 *target_addr, *orig_addr;
551         const u8 *da;
552         u8 target_flags, ttl, flags;
553         u32 orig_sn, target_sn, lifetime, target_metric = 0;
554         bool reply = false;
555         bool forward = true;
556         bool root_is_gate;
557
558         /* Update target SN, if present */
559         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
560         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
561         target_sn = PREQ_IE_TARGET_SN(preq_elem);
562         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
563         target_flags = PREQ_IE_TARGET_F(preq_elem);
564         /* Proactive PREQ gate announcements */
565         flags = PREQ_IE_FLAGS(preq_elem);
566         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
567
568         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
569
570         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
571                 mhwmp_dbg(sdata, "PREQ is for us\n");
572                 forward = false;
573                 reply = true;
574                 target_metric = 0;
575
576                 if (SN_GT(target_sn, ifmsh->sn))
577                         ifmsh->sn = target_sn;
578
579                 if (time_after(jiffies, ifmsh->last_sn_update +
580                                         net_traversal_jiffies(sdata)) ||
581                     time_before(jiffies, ifmsh->last_sn_update)) {
582                         ++ifmsh->sn;
583                         ifmsh->last_sn_update = jiffies;
584                 }
585                 target_sn = ifmsh->sn;
586         } else if (is_broadcast_ether_addr(target_addr) &&
587                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
588                 rcu_read_lock();
589                 mpath = mesh_path_lookup(sdata, orig_addr);
590                 if (mpath) {
591                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
592                                 reply = true;
593                                 target_addr = sdata->vif.addr;
594                                 target_sn = ++ifmsh->sn;
595                                 target_metric = 0;
596                                 ifmsh->last_sn_update = jiffies;
597                         }
598                         if (root_is_gate)
599                                 mesh_path_add_gate(mpath);
600                 }
601                 rcu_read_unlock();
602         } else {
603                 rcu_read_lock();
604                 mpath = mesh_path_lookup(sdata, target_addr);
605                 if (mpath) {
606                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
607                                         SN_LT(mpath->sn, target_sn)) {
608                                 mpath->sn = target_sn;
609                                 mpath->flags |= MESH_PATH_SN_VALID;
610                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
611                                         (mpath->flags & MESH_PATH_ACTIVE)) {
612                                 reply = true;
613                                 target_metric = mpath->metric;
614                                 target_sn = mpath->sn;
615                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
616                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
617                         }
618                 }
619                 rcu_read_unlock();
620         }
621
622         if (reply) {
623                 lifetime = PREQ_IE_LIFETIME(preq_elem);
624                 ttl = ifmsh->mshcfg.element_ttl;
625                 if (ttl != 0) {
626                         mhwmp_dbg(sdata, "replying to the PREQ\n");
627                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
628                                                orig_sn, 0, target_addr,
629                                                target_sn, mgmt->sa, 0, ttl,
630                                                lifetime, target_metric, 0,
631                                                sdata);
632                 } else {
633                         ifmsh->mshstats.dropped_frames_ttl++;
634                 }
635         }
636
637         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
638                 u32 preq_id;
639                 u8 hopcount;
640
641                 ttl = PREQ_IE_TTL(preq_elem);
642                 lifetime = PREQ_IE_LIFETIME(preq_elem);
643                 if (ttl <= 1) {
644                         ifmsh->mshstats.dropped_frames_ttl++;
645                         return;
646                 }
647                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
648                 --ttl;
649                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
650                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
651                 da = (mpath && mpath->is_root) ?
652                         mpath->rann_snd_addr : broadcast_addr;
653
654                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
655                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
656                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
657                 }
658
659                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
660                                        orig_sn, target_flags, target_addr,
661                                        target_sn, da, hopcount, ttl, lifetime,
662                                        orig_metric, preq_id, sdata);
663                 if (!is_multicast_ether_addr(da))
664                         ifmsh->mshstats.fwded_unicast++;
665                 else
666                         ifmsh->mshstats.fwded_mcast++;
667                 ifmsh->mshstats.fwded_frames++;
668         }
669 }
670
671
672 static inline struct sta_info *
673 next_hop_deref_protected(struct mesh_path *mpath)
674 {
675         return rcu_dereference_protected(mpath->next_hop,
676                                          lockdep_is_held(&mpath->state_lock));
677 }
678
679
680 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
681                                     struct ieee80211_mgmt *mgmt,
682                                     const u8 *prep_elem, u32 metric)
683 {
684         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
685         struct mesh_path *mpath;
686         const u8 *target_addr, *orig_addr;
687         u8 ttl, hopcount, flags;
688         u8 next_hop[ETH_ALEN];
689         u32 target_sn, orig_sn, lifetime;
690
691         mhwmp_dbg(sdata, "received PREP from %pM\n",
692                   PREP_IE_TARGET_ADDR(prep_elem));
693
694         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
695         if (ether_addr_equal(orig_addr, sdata->vif.addr))
696                 /* destination, no forwarding required */
697                 return;
698
699         if (!ifmsh->mshcfg.dot11MeshForwarding)
700                 return;
701
702         ttl = PREP_IE_TTL(prep_elem);
703         if (ttl <= 1) {
704                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
705                 return;
706         }
707
708         rcu_read_lock();
709         mpath = mesh_path_lookup(sdata, orig_addr);
710         if (mpath)
711                 spin_lock_bh(&mpath->state_lock);
712         else
713                 goto fail;
714         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
715                 spin_unlock_bh(&mpath->state_lock);
716                 goto fail;
717         }
718         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
719         spin_unlock_bh(&mpath->state_lock);
720         --ttl;
721         flags = PREP_IE_FLAGS(prep_elem);
722         lifetime = PREP_IE_LIFETIME(prep_elem);
723         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
724         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
725         target_sn = PREP_IE_TARGET_SN(prep_elem);
726         orig_sn = PREP_IE_ORIG_SN(prep_elem);
727
728         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
729                                target_addr, target_sn, next_hop, hopcount,
730                                ttl, lifetime, metric, 0, sdata);
731         rcu_read_unlock();
732
733         sdata->u.mesh.mshstats.fwded_unicast++;
734         sdata->u.mesh.mshstats.fwded_frames++;
735         return;
736
737 fail:
738         rcu_read_unlock();
739         sdata->u.mesh.mshstats.dropped_frames_no_route++;
740 }
741
742 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
743                                     struct ieee80211_mgmt *mgmt,
744                                     const u8 *perr_elem)
745 {
746         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
747         struct mesh_path *mpath;
748         u8 ttl;
749         const u8 *ta, *target_addr;
750         u32 target_sn;
751         u16 target_rcode;
752
753         ta = mgmt->sa;
754         ttl = PERR_IE_TTL(perr_elem);
755         if (ttl <= 1) {
756                 ifmsh->mshstats.dropped_frames_ttl++;
757                 return;
758         }
759         ttl--;
760         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
761         target_sn = PERR_IE_TARGET_SN(perr_elem);
762         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
763
764         rcu_read_lock();
765         mpath = mesh_path_lookup(sdata, target_addr);
766         if (mpath) {
767                 struct sta_info *sta;
768
769                 spin_lock_bh(&mpath->state_lock);
770                 sta = next_hop_deref_protected(mpath);
771                 if (mpath->flags & MESH_PATH_ACTIVE &&
772                     ether_addr_equal(ta, sta->sta.addr) &&
773                     !(mpath->flags & MESH_PATH_FIXED) &&
774                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
775                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
776                         mpath->flags &= ~MESH_PATH_ACTIVE;
777                         if (target_sn != 0)
778                                 mpath->sn = target_sn;
779                         else
780                                 mpath->sn += 1;
781                         spin_unlock_bh(&mpath->state_lock);
782                         if (!ifmsh->mshcfg.dot11MeshForwarding)
783                                 goto endperr;
784                         mesh_path_error_tx(sdata, ttl, target_addr,
785                                            target_sn, target_rcode,
786                                            broadcast_addr);
787                 } else
788                         spin_unlock_bh(&mpath->state_lock);
789         }
790 endperr:
791         rcu_read_unlock();
792 }
793
794 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
795                                     struct ieee80211_mgmt *mgmt,
796                                     const struct ieee80211_rann_ie *rann)
797 {
798         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
799         struct ieee80211_local *local = sdata->local;
800         struct sta_info *sta;
801         struct mesh_path *mpath;
802         u8 ttl, flags, hopcount;
803         const u8 *orig_addr;
804         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
805         bool root_is_gate;
806
807         ttl = rann->rann_ttl;
808         flags = rann->rann_flags;
809         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
810         orig_addr = rann->rann_addr;
811         orig_sn = le32_to_cpu(rann->rann_seq);
812         interval = le32_to_cpu(rann->rann_interval);
813         hopcount = rann->rann_hopcount;
814         hopcount++;
815         orig_metric = le32_to_cpu(rann->rann_metric);
816
817         /*  Ignore our own RANNs */
818         if (ether_addr_equal(orig_addr, sdata->vif.addr))
819                 return;
820
821         mhwmp_dbg(sdata,
822                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
823                   orig_addr, mgmt->sa, root_is_gate);
824
825         rcu_read_lock();
826         sta = sta_info_get(sdata, mgmt->sa);
827         if (!sta) {
828                 rcu_read_unlock();
829                 return;
830         }
831
832         last_hop_metric = airtime_link_metric_get(local, sta);
833         new_metric = orig_metric + last_hop_metric;
834         if (new_metric < orig_metric)
835                 new_metric = MAX_METRIC;
836
837         mpath = mesh_path_lookup(sdata, orig_addr);
838         if (!mpath) {
839                 mpath = mesh_path_add(sdata, orig_addr);
840                 if (IS_ERR(mpath)) {
841                         rcu_read_unlock();
842                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
843                         return;
844                 }
845         }
846
847         if (!(SN_LT(mpath->sn, orig_sn)) &&
848             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
849                 rcu_read_unlock();
850                 return;
851         }
852
853         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
854              (time_after(jiffies, mpath->last_preq_to_root +
855                                   root_path_confirmation_jiffies(sdata)) ||
856              time_before(jiffies, mpath->last_preq_to_root))) &&
857              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
858                 mhwmp_dbg(sdata,
859                           "time to refresh root mpath %pM\n",
860                           orig_addr);
861                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
862                 mpath->last_preq_to_root = jiffies;
863         }
864
865         mpath->sn = orig_sn;
866         mpath->rann_metric = new_metric;
867         mpath->is_root = true;
868         /* Recording RANNs sender address to send individually
869          * addressed PREQs destined for root mesh STA */
870         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
871
872         if (root_is_gate)
873                 mesh_path_add_gate(mpath);
874
875         if (ttl <= 1) {
876                 ifmsh->mshstats.dropped_frames_ttl++;
877                 rcu_read_unlock();
878                 return;
879         }
880         ttl--;
881
882         if (ifmsh->mshcfg.dot11MeshForwarding) {
883                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
884                                        orig_sn, 0, NULL, 0, broadcast_addr,
885                                        hopcount, ttl, interval,
886                                        new_metric, 0, sdata);
887         }
888
889         rcu_read_unlock();
890 }
891
892
893 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
894                             struct ieee80211_mgmt *mgmt, size_t len)
895 {
896         struct ieee802_11_elems elems;
897         size_t baselen;
898         u32 path_metric;
899         struct sta_info *sta;
900
901         /* need action_code */
902         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
903                 return;
904
905         rcu_read_lock();
906         sta = sta_info_get(sdata, mgmt->sa);
907         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
908                 rcu_read_unlock();
909                 return;
910         }
911         rcu_read_unlock();
912
913         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
914         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
915                                len - baselen, false, &elems);
916
917         if (elems.preq) {
918                 if (elems.preq_len != 37)
919                         /* Right now we support just 1 destination and no AE */
920                         return;
921                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
922                                                   MPATH_PREQ);
923                 if (path_metric)
924                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
925                                                 path_metric);
926         }
927         if (elems.prep) {
928                 if (elems.prep_len != 31)
929                         /* Right now we support no AE */
930                         return;
931                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
932                                                   MPATH_PREP);
933                 if (path_metric)
934                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
935                                                 path_metric);
936         }
937         if (elems.perr) {
938                 if (elems.perr_len != 15)
939                         /* Right now we support only one destination per PERR */
940                         return;
941                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
942         }
943         if (elems.rann)
944                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
945 }
946
947 /**
948  * mesh_queue_preq - queue a PREQ to a given destination
949  *
950  * @mpath: mesh path to discover
951  * @flags: special attributes of the PREQ to be sent
952  *
953  * Locking: the function must be called from within a rcu read lock block.
954  *
955  */
956 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
957 {
958         struct ieee80211_sub_if_data *sdata = mpath->sdata;
959         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
960         struct mesh_preq_queue *preq_node;
961
962         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
963         if (!preq_node) {
964                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
965                 return;
966         }
967
968         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
969         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
970                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
971                 kfree(preq_node);
972                 if (printk_ratelimit())
973                         mhwmp_dbg(sdata, "PREQ node queue full\n");
974                 return;
975         }
976
977         spin_lock(&mpath->state_lock);
978         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
979                 spin_unlock(&mpath->state_lock);
980                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
981                 kfree(preq_node);
982                 return;
983         }
984
985         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
986         preq_node->flags = flags;
987
988         mpath->flags |= MESH_PATH_REQ_QUEUED;
989         spin_unlock(&mpath->state_lock);
990
991         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
992         ++ifmsh->preq_queue_len;
993         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
994
995         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
996                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
997
998         else if (time_before(jiffies, ifmsh->last_preq)) {
999                 /* avoid long wait if did not send preqs for a long time
1000                  * and jiffies wrapped around
1001                  */
1002                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1003                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1004         } else
1005                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1006                                                 min_preq_int_jiff(sdata));
1007 }
1008
1009 /**
1010  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1011  *
1012  * @sdata: local mesh subif
1013  */
1014 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1015 {
1016         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1017         struct mesh_preq_queue *preq_node;
1018         struct mesh_path *mpath;
1019         u8 ttl, target_flags = 0;
1020         const u8 *da;
1021         u32 lifetime;
1022
1023         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1024         if (!ifmsh->preq_queue_len ||
1025                 time_before(jiffies, ifmsh->last_preq +
1026                                 min_preq_int_jiff(sdata))) {
1027                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1028                 return;
1029         }
1030
1031         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1032                         struct mesh_preq_queue, list);
1033         list_del(&preq_node->list);
1034         --ifmsh->preq_queue_len;
1035         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1036
1037         rcu_read_lock();
1038         mpath = mesh_path_lookup(sdata, preq_node->dst);
1039         if (!mpath)
1040                 goto enddiscovery;
1041
1042         spin_lock_bh(&mpath->state_lock);
1043         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1044                 spin_unlock_bh(&mpath->state_lock);
1045                 goto enddiscovery;
1046         }
1047         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1048         if (preq_node->flags & PREQ_Q_F_START) {
1049                 if (mpath->flags & MESH_PATH_RESOLVING) {
1050                         spin_unlock_bh(&mpath->state_lock);
1051                         goto enddiscovery;
1052                 } else {
1053                         mpath->flags &= ~MESH_PATH_RESOLVED;
1054                         mpath->flags |= MESH_PATH_RESOLVING;
1055                         mpath->discovery_retries = 0;
1056                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1057                 }
1058         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1059                         mpath->flags & MESH_PATH_RESOLVED) {
1060                 mpath->flags &= ~MESH_PATH_RESOLVING;
1061                 spin_unlock_bh(&mpath->state_lock);
1062                 goto enddiscovery;
1063         }
1064
1065         ifmsh->last_preq = jiffies;
1066
1067         if (time_after(jiffies, ifmsh->last_sn_update +
1068                                 net_traversal_jiffies(sdata)) ||
1069             time_before(jiffies, ifmsh->last_sn_update)) {
1070                 ++ifmsh->sn;
1071                 sdata->u.mesh.last_sn_update = jiffies;
1072         }
1073         lifetime = default_lifetime(sdata);
1074         ttl = sdata->u.mesh.mshcfg.element_ttl;
1075         if (ttl == 0) {
1076                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1077                 spin_unlock_bh(&mpath->state_lock);
1078                 goto enddiscovery;
1079         }
1080
1081         if (preq_node->flags & PREQ_Q_F_REFRESH)
1082                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1083         else
1084                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1085
1086         spin_unlock_bh(&mpath->state_lock);
1087         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1088         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1089                                target_flags, mpath->dst, mpath->sn, da, 0,
1090                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1091
1092         spin_lock_bh(&mpath->state_lock);
1093         if (mpath->flags & MESH_PATH_DELETED) {
1094                 spin_unlock_bh(&mpath->state_lock);
1095                 goto enddiscovery;
1096         }
1097         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1098         spin_unlock_bh(&mpath->state_lock);
1099
1100 enddiscovery:
1101         rcu_read_unlock();
1102         kfree(preq_node);
1103 }
1104
1105 /**
1106  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1107  *
1108  * @skb: 802.11 frame to be sent
1109  * @sdata: network subif the frame will be sent through
1110  *
1111  * Lookup next hop for given skb and start path discovery if no
1112  * forwarding information is found.
1113  *
1114  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1115  * skb is freeed here if no mpath could be allocated.
1116  */
1117 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1118                          struct sk_buff *skb)
1119 {
1120         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1121         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1122         struct mesh_path *mpath;
1123         struct sk_buff *skb_to_free = NULL;
1124         u8 *target_addr = hdr->addr3;
1125         int err = 0;
1126
1127         /* Nulls are only sent to peers for PS and should be pre-addressed */
1128         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1129                 return 0;
1130
1131         rcu_read_lock();
1132         err = mesh_nexthop_lookup(sdata, skb);
1133         if (!err)
1134                 goto endlookup;
1135
1136         /* no nexthop found, start resolving */
1137         mpath = mesh_path_lookup(sdata, target_addr);
1138         if (!mpath) {
1139                 mpath = mesh_path_add(sdata, target_addr);
1140                 if (IS_ERR(mpath)) {
1141                         mesh_path_discard_frame(sdata, skb);
1142                         err = PTR_ERR(mpath);
1143                         goto endlookup;
1144                 }
1145         }
1146
1147         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1148             mesh_path_sel_is_hwmp(sdata))
1149                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1150
1151         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1152                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1153
1154         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1155         ieee80211_set_qos_hdr(sdata, skb);
1156         skb_queue_tail(&mpath->frame_queue, skb);
1157         err = -ENOENT;
1158         if (skb_to_free)
1159                 mesh_path_discard_frame(sdata, skb_to_free);
1160
1161 endlookup:
1162         rcu_read_unlock();
1163         return err;
1164 }
1165
1166 /**
1167  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1168  * this function is considered "using" the associated mpath, so preempt a path
1169  * refresh if this mpath expires soon.
1170  *
1171  * @skb: 802.11 frame to be sent
1172  * @sdata: network subif the frame will be sent through
1173  *
1174  * Returns: 0 if the next hop was found. Nonzero otherwise.
1175  */
1176 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1177                         struct sk_buff *skb)
1178 {
1179         struct mesh_path *mpath;
1180         struct sta_info *next_hop;
1181         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1182         u8 *target_addr = hdr->addr3;
1183         int err = -ENOENT;
1184
1185         rcu_read_lock();
1186         mpath = mesh_path_lookup(sdata, target_addr);
1187
1188         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1189                 goto endlookup;
1190
1191         if (time_after(jiffies,
1192                        mpath->exp_time -
1193                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1194             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1195             !(mpath->flags & MESH_PATH_RESOLVING) &&
1196             !(mpath->flags & MESH_PATH_FIXED))
1197                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1198
1199         next_hop = rcu_dereference(mpath->next_hop);
1200         if (next_hop) {
1201                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1202                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1203                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1204                 err = 0;
1205         }
1206
1207 endlookup:
1208         rcu_read_unlock();
1209         return err;
1210 }
1211
1212 void mesh_path_timer(unsigned long data)
1213 {
1214         struct mesh_path *mpath = (void *) data;
1215         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1216         int ret;
1217
1218         if (sdata->local->quiescing)
1219                 return;
1220
1221         spin_lock_bh(&mpath->state_lock);
1222         if (mpath->flags & MESH_PATH_RESOLVED ||
1223                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1224                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1225                 spin_unlock_bh(&mpath->state_lock);
1226         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1227                 ++mpath->discovery_retries;
1228                 mpath->discovery_timeout *= 2;
1229                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1230                 spin_unlock_bh(&mpath->state_lock);
1231                 mesh_queue_preq(mpath, 0);
1232         } else {
1233                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1234                                   MESH_PATH_RESOLVED |
1235                                   MESH_PATH_REQ_QUEUED);
1236                 mpath->exp_time = jiffies;
1237                 spin_unlock_bh(&mpath->state_lock);
1238                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1239                         ret = mesh_path_send_to_gates(mpath);
1240                         if (ret)
1241                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1242                 } else
1243                         mesh_path_flush_pending(mpath);
1244         }
1245 }
1246
1247 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1248 {
1249         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1250         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1251         u8 flags, target_flags = 0;
1252
1253         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1254                         ? RANN_FLAG_IS_GATE : 0;
1255
1256         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1257         case IEEE80211_PROACTIVE_RANN:
1258                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1259                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1260                                        0, ifmsh->mshcfg.element_ttl,
1261                                        interval, 0, 0, sdata);
1262                 break;
1263         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1264                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1265         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1266                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1267                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1268                                 IEEE80211_PREQ_USN_FLAG;
1269                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1270                                        ++ifmsh->sn, target_flags,
1271                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1272                                        0, ifmsh->mshcfg.element_ttl, interval,
1273                                        0, ifmsh->preq_id++, sdata);
1274                 break;
1275         default:
1276                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1277                 return;
1278         }
1279 }