Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[~shefty/rdma-dev.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
20 #define MAX_PREQ_QUEUE_LEN      64
21
22 /* Destination only */
23 #define MP_F_DO 0x1
24 /* Reply and forward */
25 #define MP_F_RF 0x2
26 /* Unknown Sequence Number */
27 #define MP_F_USN    0x01
28 /* Reason code Present */
29 #define MP_F_RCODE  0x02
30
31 static void mesh_queue_preq(struct mesh_path *, u8);
32
33 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
34 {
35         if (ae)
36                 offset += 6;
37         return get_unaligned_le32(preq_elem + offset);
38 }
39
40 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
41 {
42         if (ae)
43                 offset += 6;
44         return get_unaligned_le16(preq_elem + offset);
45 }
46
47 /* HWMP IE processing macros */
48 #define AE_F                    (1<<6)
49 #define AE_F_SET(x)             (*x & AE_F)
50 #define PREQ_IE_FLAGS(x)        (*(x))
51 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
52 #define PREQ_IE_TTL(x)          (*(x + 2))
53 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
54 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
55 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
56 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
57 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
58 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
59 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
60 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
61
62
63 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
64 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
65 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
66 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
67 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
68 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
69 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
70 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
71 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
72
73 #define PERR_IE_TTL(x)          (*(x))
74 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
75 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
76 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
77 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
78
79 #define MSEC_TO_TU(x) (x*1000/1024)
80 #define SN_GT(x, y) ((s32)(y - x) < 0)
81 #define SN_LT(x, y) ((s32)(x - y) < 0)
82
83 #define net_traversal_jiffies(s) \
84         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
85 #define default_lifetime(s) \
86         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
87 #define min_preq_int_jiff(s) \
88         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
89 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
90 #define disc_timeout_jiff(s) \
91         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
92 #define root_path_confirmation_jiffies(s) \
93         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
94
95 enum mpath_frame_type {
96         MPATH_PREQ = 0,
97         MPATH_PREP,
98         MPATH_PERR,
99         MPATH_RANN
100 };
101
102 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
103
104 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
105                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
106                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
107                 __le32 lifetime, __le32 metric, __le32 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 = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
124         memset(mgmt, 0, hdr_len);
125         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
126                                           IEEE80211_STYPE_ACTION);
127
128         memcpy(mgmt->da, da, ETH_ALEN);
129         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
130         /* BSSID == SA */
131         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
132         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
133         mgmt->u.action.u.mesh_action.action_code =
134                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
135
136         switch (action) {
137         case MPATH_PREQ:
138                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
139                 ie_len = 37;
140                 pos = skb_put(skb, 2 + ie_len);
141                 *pos++ = WLAN_EID_PREQ;
142                 break;
143         case MPATH_PREP:
144                 mhwmp_dbg(sdata, "sending PREP to %pM\n", target);
145                 ie_len = 31;
146                 pos = skb_put(skb, 2 + ie_len);
147                 *pos++ = WLAN_EID_PREP;
148                 break;
149         case MPATH_RANN:
150                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
151                 ie_len = sizeof(struct ieee80211_rann_ie);
152                 pos = skb_put(skb, 2 + ie_len);
153                 *pos++ = WLAN_EID_RANN;
154                 break;
155         default:
156                 kfree_skb(skb);
157                 return -ENOTSUPP;
158                 break;
159         }
160         *pos++ = ie_len;
161         *pos++ = flags;
162         *pos++ = hop_count;
163         *pos++ = ttl;
164         if (action == MPATH_PREP) {
165                 memcpy(pos, target, ETH_ALEN);
166                 pos += ETH_ALEN;
167                 memcpy(pos, &target_sn, 4);
168                 pos += 4;
169         } else {
170                 if (action == MPATH_PREQ) {
171                         memcpy(pos, &preq_id, 4);
172                         pos += 4;
173                 }
174                 memcpy(pos, orig_addr, ETH_ALEN);
175                 pos += ETH_ALEN;
176                 memcpy(pos, &orig_sn, 4);
177                 pos += 4;
178         }
179         memcpy(pos, &lifetime, 4);      /* interval for RANN */
180         pos += 4;
181         memcpy(pos, &metric, 4);
182         pos += 4;
183         if (action == MPATH_PREQ) {
184                 *pos++ = 1; /* destination count */
185                 *pos++ = target_flags;
186                 memcpy(pos, target, ETH_ALEN);
187                 pos += ETH_ALEN;
188                 memcpy(pos, &target_sn, 4);
189                 pos += 4;
190         } else if (action == MPATH_PREP) {
191                 memcpy(pos, orig_addr, ETH_ALEN);
192                 pos += ETH_ALEN;
193                 memcpy(pos, &orig_sn, 4);
194                 pos += 4;
195         }
196
197         ieee80211_tx_skb(sdata, skb);
198         return 0;
199 }
200
201
202 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
203  *  headroom in case the frame is encrypted. */
204 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
205                 struct sk_buff *skb)
206 {
207         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
208
209         skb_set_mac_header(skb, 0);
210         skb_set_network_header(skb, 0);
211         skb_set_transport_header(skb, 0);
212
213         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
214         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
215         skb->priority = 7;
216
217         info->control.vif = &sdata->vif;
218         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
219         ieee80211_set_qos_hdr(sdata, skb);
220 }
221
222 /**
223  * mesh_send_path error - Sends a PERR mesh management frame
224  *
225  * @target: broken destination
226  * @target_sn: SN of the broken destination
227  * @target_rcode: reason code for this PERR
228  * @ra: node this frame is addressed to
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  */
234 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
235                        __le16 target_rcode, const u8 *ra,
236                        struct ieee80211_sub_if_data *sdata)
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 = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
244                       sizeof(mgmt->u.action.u.mesh_action);
245
246         if (time_before(jiffies, ifmsh->next_perr))
247                 return -EAGAIN;
248
249         skb = dev_alloc_skb(local->tx_headroom +
250                             IEEE80211_ENCRYPT_HEADROOM +
251                             IEEE80211_ENCRYPT_TAILROOM +
252                             hdr_len +
253                             2 + 15 /* PERR IE */);
254         if (!skb)
255                 return -1;
256         skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
257         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
258         memset(mgmt, 0, hdr_len);
259         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
260                                           IEEE80211_STYPE_ACTION);
261
262         memcpy(mgmt->da, ra, ETH_ALEN);
263         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
264         /* BSSID == SA */
265         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
266         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
267         mgmt->u.action.u.mesh_action.action_code =
268                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
269         ie_len = 15;
270         pos = skb_put(skb, 2 + ie_len);
271         *pos++ = WLAN_EID_PERR;
272         *pos++ = ie_len;
273         /* ttl */
274         *pos++ = ttl;
275         /* number of destinations */
276         *pos++ = 1;
277         /*
278          * flags bit, bit 1 is unset if we know the sequence number and
279          * bit 2 is set if we have a reason code
280          */
281         *pos = 0;
282         if (!target_sn)
283                 *pos |= MP_F_USN;
284         if (target_rcode)
285                 *pos |= MP_F_RCODE;
286         pos++;
287         memcpy(pos, target, ETH_ALEN);
288         pos += ETH_ALEN;
289         memcpy(pos, &target_sn, 4);
290         pos += 4;
291         memcpy(pos, &target_rcode, 2);
292
293         /* see note in function header */
294         prepare_frame_for_deferred_tx(sdata, skb);
295         ifmsh->next_perr = TU_TO_EXP_TIME(
296                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
297         ieee80211_add_pending_skb(local, skb);
298         return 0;
299 }
300
301 void ieee80211s_update_metric(struct ieee80211_local *local,
302                 struct sta_info *sta, struct sk_buff *skb)
303 {
304         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
305         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
306         int failed;
307
308         if (!ieee80211_is_data(hdr->frame_control))
309                 return;
310
311         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
312
313         /* moving average, scaled to 100 */
314         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
315         if (sta->fail_avg > 95)
316                 mesh_plink_broken(sta);
317 }
318
319 static u32 airtime_link_metric_get(struct ieee80211_local *local,
320                                    struct sta_info *sta)
321 {
322         struct rate_info rinfo;
323         /* This should be adjusted for each device */
324         int device_constant = 1 << ARITH_SHIFT;
325         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
326         int s_unit = 1 << ARITH_SHIFT;
327         int rate, err;
328         u32 tx_time, estimated_retx;
329         u64 result;
330
331         if (sta->fail_avg >= 100)
332                 return MAX_METRIC;
333
334         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
335         rate = cfg80211_calculate_bitrate(&rinfo);
336         if (WARN_ON(!rate))
337                 return MAX_METRIC;
338
339         err = (sta->fail_avg << ARITH_SHIFT) / 100;
340
341         /* bitrate is in units of 100 Kbps, while we need rate in units of
342          * 1Mbps. This will be corrected on tx_time computation.
343          */
344         tx_time = (device_constant + 10 * test_frame_len / rate);
345         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
346         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
347         return (u32)result;
348 }
349
350 /**
351  * hwmp_route_info_get - Update routing info to originator and transmitter
352  *
353  * @sdata: local mesh subif
354  * @mgmt: mesh management frame
355  * @hwmp_ie: hwmp information element (PREP or PREQ)
356  *
357  * This function updates the path routing information to the originator and the
358  * transmitter of a HWMP PREQ or PREP frame.
359  *
360  * Returns: metric to frame originator or 0 if the frame should not be further
361  * processed
362  *
363  * Notes: this function is the only place (besides user-provided info) where
364  * path routing information is updated.
365  */
366 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
367                             struct ieee80211_mgmt *mgmt,
368                             u8 *hwmp_ie, enum mpath_frame_type action)
369 {
370         struct ieee80211_local *local = sdata->local;
371         struct mesh_path *mpath;
372         struct sta_info *sta;
373         bool fresh_info;
374         u8 *orig_addr, *ta;
375         u32 orig_sn, orig_metric;
376         unsigned long orig_lifetime, exp_time;
377         u32 last_hop_metric, new_metric;
378         bool process = true;
379
380         rcu_read_lock();
381         sta = sta_info_get(sdata, mgmt->sa);
382         if (!sta) {
383                 rcu_read_unlock();
384                 return 0;
385         }
386
387         last_hop_metric = airtime_link_metric_get(local, sta);
388         /* Update and check originator routing info */
389         fresh_info = true;
390
391         switch (action) {
392         case MPATH_PREQ:
393                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
394                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
395                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
396                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
397                 break;
398         case MPATH_PREP:
399                 /* Originator here refers to the MP that was the target in the
400                  * Path Request. We divert from the nomenclature in the draft
401                  * so that we can easily use a single function to gather path
402                  * information from both PREQ and PREP frames.
403                  */
404                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
405                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
406                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
407                 orig_metric = PREP_IE_METRIC(hwmp_ie);
408                 break;
409         default:
410                 rcu_read_unlock();
411                 return 0;
412         }
413         new_metric = orig_metric + last_hop_metric;
414         if (new_metric < orig_metric)
415                 new_metric = MAX_METRIC;
416         exp_time = TU_TO_EXP_TIME(orig_lifetime);
417
418         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
419                 /* This MP is the originator, we are not interested in this
420                  * frame, except for updating transmitter's path info.
421                  */
422                 process = false;
423                 fresh_info = false;
424         } else {
425                 mpath = mesh_path_lookup(orig_addr, sdata);
426                 if (mpath) {
427                         spin_lock_bh(&mpath->state_lock);
428                         if (mpath->flags & MESH_PATH_FIXED)
429                                 fresh_info = false;
430                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
431                             (mpath->flags & MESH_PATH_SN_VALID)) {
432                                 if (SN_GT(mpath->sn, orig_sn) ||
433                                     (mpath->sn == orig_sn &&
434                                      new_metric >= mpath->metric)) {
435                                         process = false;
436                                         fresh_info = false;
437                                 }
438                         }
439                 } else {
440                         mesh_path_add(orig_addr, sdata);
441                         mpath = mesh_path_lookup(orig_addr, sdata);
442                         if (!mpath) {
443                                 rcu_read_unlock();
444                                 return 0;
445                         }
446                         spin_lock_bh(&mpath->state_lock);
447                 }
448
449                 if (fresh_info) {
450                         mesh_path_assign_nexthop(mpath, sta);
451                         mpath->flags |= MESH_PATH_SN_VALID;
452                         mpath->metric = new_metric;
453                         mpath->sn = orig_sn;
454                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
455                                           ?  mpath->exp_time : exp_time;
456                         mesh_path_activate(mpath);
457                         spin_unlock_bh(&mpath->state_lock);
458                         mesh_path_tx_pending(mpath);
459                         /* draft says preq_id should be saved to, but there does
460                          * not seem to be any use for it, skipping by now
461                          */
462                 } else
463                         spin_unlock_bh(&mpath->state_lock);
464         }
465
466         /* Update and check transmitter routing info */
467         ta = mgmt->sa;
468         if (ether_addr_equal(orig_addr, ta))
469                 fresh_info = false;
470         else {
471                 fresh_info = true;
472
473                 mpath = mesh_path_lookup(ta, sdata);
474                 if (mpath) {
475                         spin_lock_bh(&mpath->state_lock);
476                         if ((mpath->flags & MESH_PATH_FIXED) ||
477                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
478                                         (last_hop_metric > mpath->metric)))
479                                 fresh_info = false;
480                 } else {
481                         mesh_path_add(ta, sdata);
482                         mpath = mesh_path_lookup(ta, sdata);
483                         if (!mpath) {
484                                 rcu_read_unlock();
485                                 return 0;
486                         }
487                         spin_lock_bh(&mpath->state_lock);
488                 }
489
490                 if (fresh_info) {
491                         mesh_path_assign_nexthop(mpath, sta);
492                         mpath->metric = last_hop_metric;
493                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
494                                           ?  mpath->exp_time : exp_time;
495                         mesh_path_activate(mpath);
496                         spin_unlock_bh(&mpath->state_lock);
497                         mesh_path_tx_pending(mpath);
498                 } else
499                         spin_unlock_bh(&mpath->state_lock);
500         }
501
502         rcu_read_unlock();
503
504         return process ? new_metric : 0;
505 }
506
507 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
508                                     struct ieee80211_mgmt *mgmt,
509                                     u8 *preq_elem, u32 metric)
510 {
511         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
512         struct mesh_path *mpath = NULL;
513         u8 *target_addr, *orig_addr;
514         const u8 *da;
515         u8 target_flags, ttl, flags;
516         u32 orig_sn, target_sn, lifetime, orig_metric;
517         bool reply = false;
518         bool forward = true;
519         bool root_is_gate;
520
521         /* Update target SN, if present */
522         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
523         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
524         target_sn = PREQ_IE_TARGET_SN(preq_elem);
525         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
526         target_flags = PREQ_IE_TARGET_F(preq_elem);
527         orig_metric = metric;
528         /* Proactive PREQ gate announcements */
529         flags = PREQ_IE_FLAGS(preq_elem);
530         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
531
532         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
533
534         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
535                 mhwmp_dbg(sdata, "PREQ is for us\n");
536                 forward = false;
537                 reply = true;
538                 metric = 0;
539                 if (time_after(jiffies, ifmsh->last_sn_update +
540                                         net_traversal_jiffies(sdata)) ||
541                     time_before(jiffies, ifmsh->last_sn_update)) {
542                         target_sn = ++ifmsh->sn;
543                         ifmsh->last_sn_update = jiffies;
544                 }
545         } else if (is_broadcast_ether_addr(target_addr) &&
546                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
547                 rcu_read_lock();
548                 mpath = mesh_path_lookup(orig_addr, sdata);
549                 if (mpath) {
550                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
551                                 reply = true;
552                                 target_addr = sdata->vif.addr;
553                                 target_sn = ++ifmsh->sn;
554                                 metric = 0;
555                                 ifmsh->last_sn_update = jiffies;
556                         }
557                         if (root_is_gate)
558                                 mesh_path_add_gate(mpath);
559                 }
560                 rcu_read_unlock();
561         } else {
562                 rcu_read_lock();
563                 mpath = mesh_path_lookup(target_addr, sdata);
564                 if (mpath) {
565                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
566                                         SN_LT(mpath->sn, target_sn)) {
567                                 mpath->sn = target_sn;
568                                 mpath->flags |= MESH_PATH_SN_VALID;
569                         } else if ((!(target_flags & MP_F_DO)) &&
570                                         (mpath->flags & MESH_PATH_ACTIVE)) {
571                                 reply = true;
572                                 metric = mpath->metric;
573                                 target_sn = mpath->sn;
574                                 if (target_flags & MP_F_RF)
575                                         target_flags |= MP_F_DO;
576                                 else
577                                         forward = false;
578                         }
579                 }
580                 rcu_read_unlock();
581         }
582
583         if (reply) {
584                 lifetime = PREQ_IE_LIFETIME(preq_elem);
585                 ttl = ifmsh->mshcfg.element_ttl;
586                 if (ttl != 0) {
587                         mhwmp_dbg(sdata, "replying to the PREQ\n");
588                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
589                                 cpu_to_le32(orig_sn), 0, target_addr,
590                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
591                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
592                                 0, sdata);
593                 } else {
594                         ifmsh->mshstats.dropped_frames_ttl++;
595                 }
596         }
597
598         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
599                 u32 preq_id;
600                 u8 hopcount;
601
602                 ttl = PREQ_IE_TTL(preq_elem);
603                 lifetime = PREQ_IE_LIFETIME(preq_elem);
604                 if (ttl <= 1) {
605                         ifmsh->mshstats.dropped_frames_ttl++;
606                         return;
607                 }
608                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
609                 --ttl;
610                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
611                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
612                 da = (mpath && mpath->is_root) ?
613                         mpath->rann_snd_addr : broadcast_addr;
614
615                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
616                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
617                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
618                         metric = orig_metric;
619                 }
620
621                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
622                                 cpu_to_le32(orig_sn), target_flags, target_addr,
623                                 cpu_to_le32(target_sn), da,
624                                 hopcount, ttl, cpu_to_le32(lifetime),
625                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
626                                 sdata);
627                 if (!is_multicast_ether_addr(da))
628                         ifmsh->mshstats.fwded_unicast++;
629                 else
630                         ifmsh->mshstats.fwded_mcast++;
631                 ifmsh->mshstats.fwded_frames++;
632         }
633 }
634
635
636 static inline struct sta_info *
637 next_hop_deref_protected(struct mesh_path *mpath)
638 {
639         return rcu_dereference_protected(mpath->next_hop,
640                                          lockdep_is_held(&mpath->state_lock));
641 }
642
643
644 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
645                                     struct ieee80211_mgmt *mgmt,
646                                     u8 *prep_elem, u32 metric)
647 {
648         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
649         struct mesh_path *mpath;
650         u8 *target_addr, *orig_addr;
651         u8 ttl, hopcount, flags;
652         u8 next_hop[ETH_ALEN];
653         u32 target_sn, orig_sn, lifetime;
654
655         mhwmp_dbg(sdata, "received PREP from %pM\n",
656                   PREP_IE_ORIG_ADDR(prep_elem));
657
658         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
659         if (ether_addr_equal(orig_addr, sdata->vif.addr))
660                 /* destination, no forwarding required */
661                 return;
662
663         if (!ifmsh->mshcfg.dot11MeshForwarding)
664                 return;
665
666         ttl = PREP_IE_TTL(prep_elem);
667         if (ttl <= 1) {
668                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
669                 return;
670         }
671
672         rcu_read_lock();
673         mpath = mesh_path_lookup(orig_addr, sdata);
674         if (mpath)
675                 spin_lock_bh(&mpath->state_lock);
676         else
677                 goto fail;
678         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
679                 spin_unlock_bh(&mpath->state_lock);
680                 goto fail;
681         }
682         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
683         spin_unlock_bh(&mpath->state_lock);
684         --ttl;
685         flags = PREP_IE_FLAGS(prep_elem);
686         lifetime = PREP_IE_LIFETIME(prep_elem);
687         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
688         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
689         target_sn = PREP_IE_TARGET_SN(prep_elem);
690         orig_sn = PREP_IE_ORIG_SN(prep_elem);
691
692         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
693                 cpu_to_le32(orig_sn), 0, target_addr,
694                 cpu_to_le32(target_sn), next_hop, hopcount,
695                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
696                 0, sdata);
697         rcu_read_unlock();
698
699         sdata->u.mesh.mshstats.fwded_unicast++;
700         sdata->u.mesh.mshstats.fwded_frames++;
701         return;
702
703 fail:
704         rcu_read_unlock();
705         sdata->u.mesh.mshstats.dropped_frames_no_route++;
706 }
707
708 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
709                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
710 {
711         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
712         struct mesh_path *mpath;
713         u8 ttl;
714         u8 *ta, *target_addr;
715         u32 target_sn;
716         u16 target_rcode;
717
718         ta = mgmt->sa;
719         ttl = PERR_IE_TTL(perr_elem);
720         if (ttl <= 1) {
721                 ifmsh->mshstats.dropped_frames_ttl++;
722                 return;
723         }
724         ttl--;
725         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
726         target_sn = PERR_IE_TARGET_SN(perr_elem);
727         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
728
729         rcu_read_lock();
730         mpath = mesh_path_lookup(target_addr, sdata);
731         if (mpath) {
732                 struct sta_info *sta;
733
734                 spin_lock_bh(&mpath->state_lock);
735                 sta = next_hop_deref_protected(mpath);
736                 if (mpath->flags & MESH_PATH_ACTIVE &&
737                     ether_addr_equal(ta, sta->sta.addr) &&
738                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
739                     SN_GT(target_sn, mpath->sn))) {
740                         mpath->flags &= ~MESH_PATH_ACTIVE;
741                         mpath->sn = target_sn;
742                         spin_unlock_bh(&mpath->state_lock);
743                         if (!ifmsh->mshcfg.dot11MeshForwarding)
744                                 goto endperr;
745                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
746                                            cpu_to_le16(target_rcode),
747                                            broadcast_addr, sdata);
748                 } else
749                         spin_unlock_bh(&mpath->state_lock);
750         }
751 endperr:
752         rcu_read_unlock();
753 }
754
755 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
756                                 struct ieee80211_mgmt *mgmt,
757                                 struct ieee80211_rann_ie *rann)
758 {
759         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
760         struct ieee80211_local *local = sdata->local;
761         struct sta_info *sta;
762         struct mesh_path *mpath;
763         u8 ttl, flags, hopcount;
764         u8 *orig_addr;
765         u32 orig_sn, metric, metric_txsta, interval;
766         bool root_is_gate;
767
768         ttl = rann->rann_ttl;
769         flags = rann->rann_flags;
770         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
771         orig_addr = rann->rann_addr;
772         orig_sn = le32_to_cpu(rann->rann_seq);
773         interval = le32_to_cpu(rann->rann_interval);
774         hopcount = rann->rann_hopcount;
775         hopcount++;
776         metric = le32_to_cpu(rann->rann_metric);
777
778         /*  Ignore our own RANNs */
779         if (ether_addr_equal(orig_addr, sdata->vif.addr))
780                 return;
781
782         mhwmp_dbg(sdata,
783                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
784                   orig_addr, mgmt->sa, root_is_gate);
785
786         rcu_read_lock();
787         sta = sta_info_get(sdata, mgmt->sa);
788         if (!sta) {
789                 rcu_read_unlock();
790                 return;
791         }
792
793         metric_txsta = airtime_link_metric_get(local, sta);
794
795         mpath = mesh_path_lookup(orig_addr, sdata);
796         if (!mpath) {
797                 mesh_path_add(orig_addr, sdata);
798                 mpath = mesh_path_lookup(orig_addr, sdata);
799                 if (!mpath) {
800                         rcu_read_unlock();
801                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
802                         return;
803                 }
804         }
805
806         if (!(SN_LT(mpath->sn, orig_sn)) &&
807             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
808                 rcu_read_unlock();
809                 return;
810         }
811
812         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
813              (time_after(jiffies, mpath->last_preq_to_root +
814                                   root_path_confirmation_jiffies(sdata)) ||
815              time_before(jiffies, mpath->last_preq_to_root))) &&
816              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
817                 mhwmp_dbg(sdata,
818                           "time to refresh root mpath %pM\n",
819                           orig_addr);
820                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
821                 mpath->last_preq_to_root = jiffies;
822         }
823
824         mpath->sn = orig_sn;
825         mpath->rann_metric = metric + metric_txsta;
826         mpath->is_root = true;
827         /* Recording RANNs sender address to send individually
828          * addressed PREQs destined for root mesh STA */
829         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
830
831         if (root_is_gate)
832                 mesh_path_add_gate(mpath);
833
834         if (ttl <= 1) {
835                 ifmsh->mshstats.dropped_frames_ttl++;
836                 rcu_read_unlock();
837                 return;
838         }
839         ttl--;
840
841         if (ifmsh->mshcfg.dot11MeshForwarding) {
842                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
843                                        cpu_to_le32(orig_sn),
844                                        0, NULL, 0, broadcast_addr,
845                                        hopcount, ttl, cpu_to_le32(interval),
846                                        cpu_to_le32(metric + metric_txsta),
847                                        0, sdata);
848         }
849
850         rcu_read_unlock();
851 }
852
853
854 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
855                             struct ieee80211_mgmt *mgmt,
856                             size_t len)
857 {
858         struct ieee802_11_elems elems;
859         size_t baselen;
860         u32 last_hop_metric;
861         struct sta_info *sta;
862
863         /* need action_code */
864         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
865                 return;
866
867         rcu_read_lock();
868         sta = sta_info_get(sdata, mgmt->sa);
869         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
870                 rcu_read_unlock();
871                 return;
872         }
873         rcu_read_unlock();
874
875         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
876         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
877                         len - baselen, &elems);
878
879         if (elems.preq) {
880                 if (elems.preq_len != 37)
881                         /* Right now we support just 1 destination and no AE */
882                         return;
883                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
884                                                       MPATH_PREQ);
885                 if (last_hop_metric)
886                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
887                                                 last_hop_metric);
888         }
889         if (elems.prep) {
890                 if (elems.prep_len != 31)
891                         /* Right now we support no AE */
892                         return;
893                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
894                                                       MPATH_PREP);
895                 if (last_hop_metric)
896                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
897                                                 last_hop_metric);
898         }
899         if (elems.perr) {
900                 if (elems.perr_len != 15)
901                         /* Right now we support only one destination per PERR */
902                         return;
903                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
904         }
905         if (elems.rann)
906                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
907 }
908
909 /**
910  * mesh_queue_preq - queue a PREQ to a given destination
911  *
912  * @mpath: mesh path to discover
913  * @flags: special attributes of the PREQ to be sent
914  *
915  * Locking: the function must be called from within a rcu read lock block.
916  *
917  */
918 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
919 {
920         struct ieee80211_sub_if_data *sdata = mpath->sdata;
921         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
922         struct mesh_preq_queue *preq_node;
923
924         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
925         if (!preq_node) {
926                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
927                 return;
928         }
929
930         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
931         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
932                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
933                 kfree(preq_node);
934                 if (printk_ratelimit())
935                         mhwmp_dbg(sdata, "PREQ node queue full\n");
936                 return;
937         }
938
939         spin_lock(&mpath->state_lock);
940         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
941                 spin_unlock(&mpath->state_lock);
942                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
943                 kfree(preq_node);
944                 return;
945         }
946
947         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
948         preq_node->flags = flags;
949
950         mpath->flags |= MESH_PATH_REQ_QUEUED;
951         spin_unlock(&mpath->state_lock);
952
953         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
954         ++ifmsh->preq_queue_len;
955         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
956
957         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
958                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
959
960         else if (time_before(jiffies, ifmsh->last_preq)) {
961                 /* avoid long wait if did not send preqs for a long time
962                  * and jiffies wrapped around
963                  */
964                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
965                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
966         } else
967                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
968                                                 min_preq_int_jiff(sdata));
969 }
970
971 /**
972  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
973  *
974  * @sdata: local mesh subif
975  */
976 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
977 {
978         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
979         struct mesh_preq_queue *preq_node;
980         struct mesh_path *mpath;
981         u8 ttl, target_flags;
982         const u8 *da;
983         u32 lifetime;
984
985         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
986         if (!ifmsh->preq_queue_len ||
987                 time_before(jiffies, ifmsh->last_preq +
988                                 min_preq_int_jiff(sdata))) {
989                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
990                 return;
991         }
992
993         preq_node = list_first_entry(&ifmsh->preq_queue.list,
994                         struct mesh_preq_queue, list);
995         list_del(&preq_node->list);
996         --ifmsh->preq_queue_len;
997         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
998
999         rcu_read_lock();
1000         mpath = mesh_path_lookup(preq_node->dst, sdata);
1001         if (!mpath)
1002                 goto enddiscovery;
1003
1004         spin_lock_bh(&mpath->state_lock);
1005         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1006         if (preq_node->flags & PREQ_Q_F_START) {
1007                 if (mpath->flags & MESH_PATH_RESOLVING) {
1008                         spin_unlock_bh(&mpath->state_lock);
1009                         goto enddiscovery;
1010                 } else {
1011                         mpath->flags &= ~MESH_PATH_RESOLVED;
1012                         mpath->flags |= MESH_PATH_RESOLVING;
1013                         mpath->discovery_retries = 0;
1014                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1015                 }
1016         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1017                         mpath->flags & MESH_PATH_RESOLVED) {
1018                 mpath->flags &= ~MESH_PATH_RESOLVING;
1019                 spin_unlock_bh(&mpath->state_lock);
1020                 goto enddiscovery;
1021         }
1022
1023         ifmsh->last_preq = jiffies;
1024
1025         if (time_after(jiffies, ifmsh->last_sn_update +
1026                                 net_traversal_jiffies(sdata)) ||
1027             time_before(jiffies, ifmsh->last_sn_update)) {
1028                 ++ifmsh->sn;
1029                 sdata->u.mesh.last_sn_update = jiffies;
1030         }
1031         lifetime = default_lifetime(sdata);
1032         ttl = sdata->u.mesh.mshcfg.element_ttl;
1033         if (ttl == 0) {
1034                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1035                 spin_unlock_bh(&mpath->state_lock);
1036                 goto enddiscovery;
1037         }
1038
1039         if (preq_node->flags & PREQ_Q_F_REFRESH)
1040                 target_flags = MP_F_DO;
1041         else
1042                 target_flags = MP_F_RF;
1043
1044         spin_unlock_bh(&mpath->state_lock);
1045         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1046         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1047                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1048                         cpu_to_le32(mpath->sn), da, 0,
1049                         ttl, cpu_to_le32(lifetime), 0,
1050                         cpu_to_le32(ifmsh->preq_id++), sdata);
1051         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1052
1053 enddiscovery:
1054         rcu_read_unlock();
1055         kfree(preq_node);
1056 }
1057
1058 /**
1059  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1060  *
1061  * @skb: 802.11 frame to be sent
1062  * @sdata: network subif the frame will be sent through
1063  *
1064  * Lookup next hop for given skb and start path discovery if no
1065  * forwarding information is found.
1066  *
1067  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1068  * skb is freeed here if no mpath could be allocated.
1069  */
1070 int mesh_nexthop_resolve(struct sk_buff *skb,
1071                          struct ieee80211_sub_if_data *sdata)
1072 {
1073         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1074         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1075         struct mesh_path *mpath;
1076         struct sk_buff *skb_to_free = NULL;
1077         u8 *target_addr = hdr->addr3;
1078         int err = 0;
1079
1080         rcu_read_lock();
1081         err = mesh_nexthop_lookup(skb, sdata);
1082         if (!err)
1083                 goto endlookup;
1084
1085         /* no nexthop found, start resolving */
1086         mpath = mesh_path_lookup(target_addr, sdata);
1087         if (!mpath) {
1088                 mesh_path_add(target_addr, sdata);
1089                 mpath = mesh_path_lookup(target_addr, sdata);
1090                 if (!mpath) {
1091                         mesh_path_discard_frame(skb, sdata);
1092                         err = -ENOSPC;
1093                         goto endlookup;
1094                 }
1095         }
1096
1097         if (!(mpath->flags & MESH_PATH_RESOLVING))
1098                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1099
1100         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1101                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1102
1103         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1104         ieee80211_set_qos_hdr(sdata, skb);
1105         skb_queue_tail(&mpath->frame_queue, skb);
1106         err = -ENOENT;
1107         if (skb_to_free)
1108                 mesh_path_discard_frame(skb_to_free, sdata);
1109
1110 endlookup:
1111         rcu_read_unlock();
1112         return err;
1113 }
1114 /**
1115  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1116  * this function is considered "using" the associated mpath, so preempt a path
1117  * refresh if this mpath expires soon.
1118  *
1119  * @skb: 802.11 frame to be sent
1120  * @sdata: network subif the frame will be sent through
1121  *
1122  * Returns: 0 if the next hop was found. Nonzero otherwise.
1123  */
1124 int mesh_nexthop_lookup(struct sk_buff *skb,
1125                         struct ieee80211_sub_if_data *sdata)
1126 {
1127         struct mesh_path *mpath;
1128         struct sta_info *next_hop;
1129         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1130         u8 *target_addr = hdr->addr3;
1131         int err = -ENOENT;
1132
1133         rcu_read_lock();
1134         mpath = mesh_path_lookup(target_addr, sdata);
1135
1136         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1137                 goto endlookup;
1138
1139         if (time_after(jiffies,
1140                        mpath->exp_time -
1141                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1142             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1143             !(mpath->flags & MESH_PATH_RESOLVING) &&
1144             !(mpath->flags & MESH_PATH_FIXED))
1145                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1146
1147         next_hop = rcu_dereference(mpath->next_hop);
1148         if (next_hop) {
1149                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1150                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1151                 err = 0;
1152         }
1153
1154 endlookup:
1155         rcu_read_unlock();
1156         return err;
1157 }
1158
1159 void mesh_path_timer(unsigned long data)
1160 {
1161         struct mesh_path *mpath = (void *) data;
1162         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1163         int ret;
1164
1165         if (sdata->local->quiescing)
1166                 return;
1167
1168         spin_lock_bh(&mpath->state_lock);
1169         if (mpath->flags & MESH_PATH_RESOLVED ||
1170                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1171                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1172                 spin_unlock_bh(&mpath->state_lock);
1173         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1174                 ++mpath->discovery_retries;
1175                 mpath->discovery_timeout *= 2;
1176                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1177                 spin_unlock_bh(&mpath->state_lock);
1178                 mesh_queue_preq(mpath, 0);
1179         } else {
1180                 mpath->flags = 0;
1181                 mpath->exp_time = jiffies;
1182                 spin_unlock_bh(&mpath->state_lock);
1183                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1184                         ret = mesh_path_send_to_gates(mpath);
1185                         if (ret)
1186                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1187                 } else
1188                         mesh_path_flush_pending(mpath);
1189         }
1190 }
1191
1192 void
1193 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1194 {
1195         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1196         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1197         u8 flags, target_flags = 0;
1198
1199         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1200                         ? RANN_FLAG_IS_GATE : 0;
1201
1202         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1203         case IEEE80211_PROACTIVE_RANN:
1204                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1205                                cpu_to_le32(++ifmsh->sn),
1206                                0, NULL, 0, broadcast_addr,
1207                                0, ifmsh->mshcfg.element_ttl,
1208                                cpu_to_le32(interval), 0, 0, sdata);
1209                 break;
1210         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1211                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1212         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1213                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1214                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1215                                 IEEE80211_PREQ_USN_FLAG;
1216                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1217                                 cpu_to_le32(++ifmsh->sn), target_flags,
1218                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1219                                 0, ifmsh->mshcfg.element_ttl,
1220                                 cpu_to_le32(interval),
1221                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1222                 break;
1223         default:
1224                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1225                 return;
1226         }
1227 }