mac80211: replace "destination" with "target" to follow the spec
[linux-2.6.git] / net / mac80211 / mesh_hwmp.c
1 /*
2  * Copyright (c) 2008 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 "mesh.h"
11
12 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
13 #define mhwmp_dbg(fmt, args...)   printk(KERN_DEBUG "Mesh HWMP: " fmt, ##args)
14 #else
15 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
16 #endif
17
18 #define TEST_FRAME_LEN  8192
19 #define MAX_METRIC      0xffffffff
20 #define ARITH_SHIFT     8
21
22 /* Number of frames buffered per destination for unresolved destinations */
23 #define MESH_FRAME_QUEUE_LEN    10
24 #define MAX_PREQ_QUEUE_LEN      64
25
26 /* Destination only */
27 #define MP_F_DO 0x1
28 /* Reply and forward */
29 #define MP_F_RF 0x2
30 /* Unknown Sequence Number */
31 #define MP_F_USN    0x01
32 /* Reason code Present */
33 #define MP_F_RCODE  0x02
34
35 static void mesh_queue_preq(struct mesh_path *, u8);
36
37 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
38 {
39         if (ae)
40                 offset += 6;
41         return get_unaligned_le32(preq_elem + offset);
42 }
43
44 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
45 {
46         if (ae)
47                 offset += 6;
48         return get_unaligned_le16(preq_elem + offset);
49 }
50
51 /* HWMP IE processing macros */
52 #define AE_F                    (1<<6)
53 #define AE_F_SET(x)             (*x & AE_F)
54 #define PREQ_IE_FLAGS(x)        (*(x))
55 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
56 #define PREQ_IE_TTL(x)          (*(x + 2))
57 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
58 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
59 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0);
60 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x));
61 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x));
62 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
63 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
64 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x));
65
66
67 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
68 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
69 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
70 #define PREP_IE_ORIG_ADDR(x)    (x + 3)
71 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 9, 0);
72 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x));
73 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x));
74 #define PREP_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 27 : x + 21)
75 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 27, AE_F_SET(x));
76
77 #define PERR_IE_TTL(x)          (*(x))
78 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
79 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
80 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0);
81 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0);
82
83 #define MSEC_TO_TU(x) (x*1000/1024)
84 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
85 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
86
87 #define net_traversal_jiffies(s) \
88         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
89 #define default_lifetime(s) \
90         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
91 #define min_preq_int_jiff(s) \
92         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
93 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
94 #define disc_timeout_jiff(s) \
95         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
96
97 enum mpath_frame_type {
98         MPATH_PREQ = 0,
99         MPATH_PREP,
100         MPATH_PERR,
101         MPATH_RANN
102 };
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, u8 *da, u8 hop_count, u8 ttl,__le32 lifetime,
107                 __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 = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
112         struct ieee80211_mgmt *mgmt;
113         u8 *pos;
114         int ie_len;
115
116         if (!skb)
117                 return -1;
118         skb_reserve(skb, local->hw.extra_tx_headroom);
119         /* 25 is the size of the common mgmt part (24) plus the size of the
120          * common action part (1)
121          */
122         mgmt = (struct ieee80211_mgmt *)
123                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
124         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
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->dev->dev_addr, ETH_ALEN);
130         /* BSSID == SA */
131         memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
132         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
133         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
134
135         switch (action) {
136         case MPATH_PREQ:
137                 mhwmp_dbg("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("sending PREP to %pM\n", target);
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("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                 break;
158         }
159         *pos++ = ie_len;
160         *pos++ = flags;
161         *pos++ = hop_count;
162         *pos++ = ttl;
163         if (action == MPATH_PREQ) {
164                 memcpy(pos, &preq_id, 4);
165                 pos += 4;
166         }
167         memcpy(pos, orig_addr, ETH_ALEN);
168         pos += ETH_ALEN;
169         memcpy(pos, &orig_sn, 4);
170         pos += 4;
171         if (action != MPATH_RANN) {
172                 memcpy(pos, &lifetime, 4);
173                 pos += 4;
174         }
175         memcpy(pos, &metric, 4);
176         pos += 4;
177         if (action == MPATH_PREQ) {
178                 /* destination count */
179                 *pos++ = 1;
180                 *pos++ = target_flags;
181         }
182         if (action != MPATH_RANN) {
183                 memcpy(pos, target, ETH_ALEN);
184                 pos += ETH_ALEN;
185                 memcpy(pos, &target_sn, 4);
186         }
187
188         ieee80211_tx_skb(sdata, skb, 1);
189         return 0;
190 }
191
192 /**
193  * mesh_send_path error - Sends a PERR mesh management frame
194  *
195  * @target: broken destination
196  * @target_sn: SN of the broken destination
197  * @target_rcode: reason code for this PERR
198  * @ra: node this frame is addressed to
199  */
200 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
201                 __le16 target_rcode, u8 *ra,
202                 struct ieee80211_sub_if_data *sdata)
203 {
204         struct ieee80211_local *local = sdata->local;
205         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
206         struct ieee80211_mgmt *mgmt;
207         u8 *pos;
208         int ie_len;
209
210         if (!skb)
211                 return -1;
212         skb_reserve(skb, local->hw.extra_tx_headroom);
213         /* 25 is the size of the common mgmt part (24) plus the size of the
214          * common action part (1)
215          */
216         mgmt = (struct ieee80211_mgmt *)
217                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
218         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
219         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
220                                           IEEE80211_STYPE_ACTION);
221
222         memcpy(mgmt->da, ra, ETH_ALEN);
223         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
224         /* BSSID is left zeroed, wildcard value */
225         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
226         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
227         ie_len = 15;
228         pos = skb_put(skb, 2 + ie_len);
229         *pos++ = WLAN_EID_PERR;
230         *pos++ = ie_len;
231         /* ttl */
232         *pos++ = MESH_TTL;
233         /* number of destinations */
234         *pos++ = 1;
235         /*
236          * flags bit, bit 1 is unset if we know the sequence number and
237          * bit 2 is set if we have a reason code
238          */
239         *pos = 0;
240         if (!target_sn)
241                 *pos |= MP_F_USN;
242         if (target_rcode)
243                 *pos |= MP_F_RCODE;
244         pos++;
245         memcpy(pos, target, ETH_ALEN);
246         pos += ETH_ALEN;
247         memcpy(pos, &target_sn, 4);
248         pos += 4;
249         memcpy(pos, &target_rcode, 2);
250
251         ieee80211_tx_skb(sdata, skb, 1);
252         return 0;
253 }
254
255 void ieee80211s_update_metric(struct ieee80211_local *local,
256                 struct sta_info *stainfo, struct sk_buff *skb)
257 {
258         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
259         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
260         int failed;
261
262         if (!ieee80211_is_data(hdr->frame_control))
263                 return;
264
265         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
266
267         /* moving average, scaled to 100 */
268         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
269         if (stainfo->fail_avg > 95)
270                 mesh_plink_broken(stainfo);
271 }
272
273 static u32 airtime_link_metric_get(struct ieee80211_local *local,
274                                    struct sta_info *sta)
275 {
276         struct ieee80211_supported_band *sband;
277         /* This should be adjusted for each device */
278         int device_constant = 1 << ARITH_SHIFT;
279         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
280         int s_unit = 1 << ARITH_SHIFT;
281         int rate, err;
282         u32 tx_time, estimated_retx;
283         u64 result;
284
285         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
286
287         if (sta->fail_avg >= 100)
288                 return MAX_METRIC;
289
290         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
291                 return MAX_METRIC;
292
293         err = (sta->fail_avg << ARITH_SHIFT) / 100;
294
295         /* bitrate is in units of 100 Kbps, while we need rate in units of
296          * 1Mbps. This will be corrected on tx_time computation.
297          */
298         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
299         tx_time = (device_constant + 10 * test_frame_len / rate);
300         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
301         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
302         return (u32)result;
303 }
304
305 /**
306  * hwmp_route_info_get - Update routing info to originator and transmitter
307  *
308  * @sdata: local mesh subif
309  * @mgmt: mesh management frame
310  * @hwmp_ie: hwmp information element (PREP or PREQ)
311  *
312  * This function updates the path routing information to the originator and the
313  * transmitter of a HWMP PREQ or PREP frame.
314  *
315  * Returns: metric to frame originator or 0 if the frame should not be further
316  * processed
317  *
318  * Notes: this function is the only place (besides user-provided info) where
319  * path routing information is updated.
320  */
321 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
322                             struct ieee80211_mgmt *mgmt,
323                             u8 *hwmp_ie, enum mpath_frame_type action)
324 {
325         struct ieee80211_local *local = sdata->local;
326         struct mesh_path *mpath;
327         struct sta_info *sta;
328         bool fresh_info;
329         u8 *orig_addr, *ta;
330         u32 orig_sn, orig_metric;
331         unsigned long orig_lifetime, exp_time;
332         u32 last_hop_metric, new_metric;
333         bool process = true;
334
335         rcu_read_lock();
336         sta = sta_info_get(local, mgmt->sa);
337         if (!sta) {
338                 rcu_read_unlock();
339                 return 0;
340         }
341
342         last_hop_metric = airtime_link_metric_get(local, sta);
343         /* Update and check originator routing info */
344         fresh_info = true;
345
346         switch (action) {
347         case MPATH_PREQ:
348                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
349                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
350                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
351                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
352                 break;
353         case MPATH_PREP:
354                 /* Originator here refers to the MP that was the destination in
355                  * the Path Request. The draft refers to that MP as the
356                  * destination address, even though usually it is the origin of
357                  * the PREP frame. We divert from the nomenclature in the draft
358                  * so that we can easily use a single function to gather path
359                  * information from both PREQ and PREP frames.
360                  */
361                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
362                 orig_sn = PREP_IE_ORIG_SN(hwmp_ie);
363                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
364                 orig_metric = PREP_IE_METRIC(hwmp_ie);
365                 break;
366         default:
367                 rcu_read_unlock();
368                 return 0;
369         }
370         new_metric = orig_metric + last_hop_metric;
371         if (new_metric < orig_metric)
372                 new_metric = MAX_METRIC;
373         exp_time = TU_TO_EXP_TIME(orig_lifetime);
374
375         if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
376                 /* This MP is the originator, we are not interested in this
377                  * frame, except for updating transmitter's path info.
378                  */
379                 process = false;
380                 fresh_info = false;
381         } else {
382                 mpath = mesh_path_lookup(orig_addr, sdata);
383                 if (mpath) {
384                         spin_lock_bh(&mpath->state_lock);
385                         if (mpath->flags & MESH_PATH_FIXED)
386                                 fresh_info = false;
387                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
388                             (mpath->flags & MESH_PATH_SN_VALID)) {
389                                 if (SN_GT(mpath->sn, orig_sn) ||
390                                     (mpath->sn == orig_sn &&
391                                      action == MPATH_PREQ &&
392                                      new_metric > mpath->metric)) {
393                                         process = false;
394                                         fresh_info = false;
395                                 }
396                         }
397                 } else {
398                         mesh_path_add(orig_addr, sdata);
399                         mpath = mesh_path_lookup(orig_addr, sdata);
400                         if (!mpath) {
401                                 rcu_read_unlock();
402                                 return 0;
403                         }
404                         spin_lock_bh(&mpath->state_lock);
405                 }
406
407                 if (fresh_info) {
408                         mesh_path_assign_nexthop(mpath, sta);
409                         mpath->flags |= MESH_PATH_SN_VALID;
410                         mpath->metric = new_metric;
411                         mpath->sn = orig_sn;
412                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
413                                           ?  mpath->exp_time : exp_time;
414                         mesh_path_activate(mpath);
415                         spin_unlock_bh(&mpath->state_lock);
416                         mesh_path_tx_pending(mpath);
417                         /* draft says preq_id should be saved to, but there does
418                          * not seem to be any use for it, skipping by now
419                          */
420                 } else
421                         spin_unlock_bh(&mpath->state_lock);
422         }
423
424         /* Update and check transmitter routing info */
425         ta = mgmt->sa;
426         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
427                 fresh_info = false;
428         else {
429                 fresh_info = true;
430
431                 mpath = mesh_path_lookup(ta, sdata);
432                 if (mpath) {
433                         spin_lock_bh(&mpath->state_lock);
434                         if ((mpath->flags & MESH_PATH_FIXED) ||
435                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
436                                         (last_hop_metric > mpath->metric)))
437                                 fresh_info = false;
438                 } else {
439                         mesh_path_add(ta, sdata);
440                         mpath = mesh_path_lookup(ta, sdata);
441                         if (!mpath) {
442                                 rcu_read_unlock();
443                                 return 0;
444                         }
445                         spin_lock_bh(&mpath->state_lock);
446                 }
447
448                 if (fresh_info) {
449                         mesh_path_assign_nexthop(mpath, sta);
450                         mpath->flags &= ~MESH_PATH_SN_VALID;
451                         mpath->metric = last_hop_metric;
452                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
453                                           ?  mpath->exp_time : exp_time;
454                         mesh_path_activate(mpath);
455                         spin_unlock_bh(&mpath->state_lock);
456                         mesh_path_tx_pending(mpath);
457                 } else
458                         spin_unlock_bh(&mpath->state_lock);
459         }
460
461         rcu_read_unlock();
462
463         return process ? new_metric : 0;
464 }
465
466 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
467                                     struct ieee80211_mgmt *mgmt,
468                                     u8 *preq_elem, u32 metric)
469 {
470         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
471         struct mesh_path *mpath;
472         u8 *target_addr, *orig_addr;
473         u8 target_flags, ttl;
474         u32 orig_sn, target_sn, lifetime;
475         bool reply = false;
476         bool forward = true;
477
478         /* Update target SN, if present */
479         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
480         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
481         target_sn = PREQ_IE_TARGET_SN(preq_elem);
482         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
483         target_flags = PREQ_IE_TARGET_F(preq_elem);
484
485         mhwmp_dbg("received PREQ from %pM\n", orig_addr);
486
487         if (memcmp(target_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
488                 mhwmp_dbg("PREQ is for us\n");
489                 forward = false;
490                 reply = true;
491                 metric = 0;
492                 if (time_after(jiffies, ifmsh->last_sn_update +
493                                         net_traversal_jiffies(sdata)) ||
494                     time_before(jiffies, ifmsh->last_sn_update)) {
495                         target_sn = ++ifmsh->sn;
496                         ifmsh->last_sn_update = jiffies;
497                 }
498         } else {
499                 rcu_read_lock();
500                 mpath = mesh_path_lookup(target_addr, sdata);
501                 if (mpath) {
502                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
503                                         SN_LT(mpath->sn, target_sn)) {
504                                 mpath->sn = target_sn;
505                                 mpath->flags |= MESH_PATH_SN_VALID;
506                         } else if ((!(target_flags & MP_F_DO)) &&
507                                         (mpath->flags & MESH_PATH_ACTIVE)) {
508                                 reply = true;
509                                 metric = mpath->metric;
510                                 target_sn = mpath->sn;
511                                 if (target_flags & MP_F_RF)
512                                         target_flags |= MP_F_DO;
513                                 else
514                                         forward = false;
515                         }
516                 }
517                 rcu_read_unlock();
518         }
519
520         if (reply) {
521                 lifetime = PREQ_IE_LIFETIME(preq_elem);
522                 ttl = ifmsh->mshcfg.dot11MeshTTL;
523                 if (ttl != 0) {
524                         mhwmp_dbg("replying to the PREQ\n");
525                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
526                                 cpu_to_le32(target_sn), 0, orig_addr,
527                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
528                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
529                                 0, sdata);
530                 } else
531                         ifmsh->mshstats.dropped_frames_ttl++;
532         }
533
534         if (forward) {
535                 u32 preq_id;
536                 u8 hopcount, flags;
537
538                 ttl = PREQ_IE_TTL(preq_elem);
539                 lifetime = PREQ_IE_LIFETIME(preq_elem);
540                 if (ttl <= 1) {
541                         ifmsh->mshstats.dropped_frames_ttl++;
542                         return;
543                 }
544                 mhwmp_dbg("forwarding the PREQ from %pM\n", orig_addr);
545                 --ttl;
546                 flags = PREQ_IE_FLAGS(preq_elem);
547                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
548                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
549                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
550                                 cpu_to_le32(orig_sn), target_flags, target_addr,
551                                 cpu_to_le32(target_sn), sdata->dev->broadcast,
552                                 hopcount, ttl, cpu_to_le32(lifetime),
553                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
554                                 sdata);
555                 ifmsh->mshstats.fwded_mcast++;
556                 ifmsh->mshstats.fwded_frames++;
557         }
558 }
559
560
561 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
562                                     struct ieee80211_mgmt *mgmt,
563                                     u8 *prep_elem, u32 metric)
564 {
565         struct mesh_path *mpath;
566         u8 *target_addr, *orig_addr;
567         u8 ttl, hopcount, flags;
568         u8 next_hop[ETH_ALEN];
569         u32 target_sn, orig_sn, lifetime;
570
571         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
572
573         /* Note that we divert from the draft nomenclature and denominate
574          * destination to what the draft refers to as origininator. So in this
575          * function destnation refers to the final destination of the PREP,
576          * which corresponds with the originator of the PREQ which this PREP
577          * replies
578          */
579         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
580         if (memcmp(target_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
581                 /* destination, no forwarding required */
582                 return;
583
584         ttl = PREP_IE_TTL(prep_elem);
585         if (ttl <= 1) {
586                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
587                 return;
588         }
589
590         rcu_read_lock();
591         mpath = mesh_path_lookup(target_addr, sdata);
592         if (mpath)
593                 spin_lock_bh(&mpath->state_lock);
594         else
595                 goto fail;
596         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
597                 spin_unlock_bh(&mpath->state_lock);
598                 goto fail;
599         }
600         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
601         spin_unlock_bh(&mpath->state_lock);
602         --ttl;
603         flags = PREP_IE_FLAGS(prep_elem);
604         lifetime = PREP_IE_LIFETIME(prep_elem);
605         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
606         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
607         target_sn = PREP_IE_TARGET_SN(prep_elem);
608         orig_sn = PREP_IE_ORIG_SN(prep_elem);
609
610         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
611                 cpu_to_le32(orig_sn), 0, target_addr,
612                 cpu_to_le32(target_sn), mpath->next_hop->sta.addr, hopcount,
613                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
614                 0, sdata);
615         rcu_read_unlock();
616
617         sdata->u.mesh.mshstats.fwded_unicast++;
618         sdata->u.mesh.mshstats.fwded_frames++;
619         return;
620
621 fail:
622         rcu_read_unlock();
623         sdata->u.mesh.mshstats.dropped_frames_no_route++;
624         return;
625 }
626
627 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
628                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
629 {
630         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
631         struct mesh_path *mpath;
632         u8 ttl;
633         u8 *ta, *target_addr;
634         u8 target_flags;
635         u32 target_sn;
636         u16 target_rcode;
637
638         ta = mgmt->sa;
639         ttl = PERR_IE_TTL(perr_elem);
640         if (ttl <= 1) {
641                 ifmsh->mshstats.dropped_frames_ttl++;
642                 return;
643         }
644         ttl--;
645         target_flags = PERR_IE_TARGET_FLAGS(perr_elem);
646         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
647         target_sn = PERR_IE_TARGET_SN(perr_elem);
648         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
649
650         rcu_read_lock();
651         mpath = mesh_path_lookup(target_addr, sdata);
652         if (mpath) {
653                 spin_lock_bh(&mpath->state_lock);
654                 if (mpath->flags & MESH_PATH_ACTIVE &&
655                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
656                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
657                     SN_GT(target_sn, mpath->sn))) {
658                         mpath->flags &= ~MESH_PATH_ACTIVE;
659                         mpath->sn = target_sn;
660                         spin_unlock_bh(&mpath->state_lock);
661                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
662                                            cpu_to_le16(target_rcode),
663                                            sdata->dev->broadcast, sdata);
664                 } else
665                         spin_unlock_bh(&mpath->state_lock);
666         }
667         rcu_read_unlock();
668 }
669
670 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
671                                 struct ieee80211_mgmt *mgmt,
672                                 struct ieee80211_rann_ie *rann)
673 {
674         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
675         struct mesh_path *mpath;
676         u8 *ta;
677         u8 ttl, flags, hopcount;
678         u8 *orig_addr;
679         u32 orig_sn, metric;
680
681         ta = mgmt->sa;
682         ttl = rann->rann_ttl;
683         if (ttl <= 1) {
684                 ifmsh->mshstats.dropped_frames_ttl++;
685                 return;
686         }
687         ttl--;
688         flags = rann->rann_flags;
689         orig_addr = rann->rann_addr;
690         orig_sn = rann->rann_seq;
691         hopcount = rann->rann_hopcount;
692         hopcount++;
693         metric = rann->rann_metric;
694         mhwmp_dbg("received RANN from %pM\n", orig_addr);
695
696         rcu_read_lock();
697         mpath = mesh_path_lookup(orig_addr, sdata);
698         if (!mpath) {
699                 mesh_path_add(orig_addr, sdata);
700                 mpath = mesh_path_lookup(orig_addr, sdata);
701                 if (!mpath) {
702                         rcu_read_unlock();
703                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
704                         return;
705                 }
706                 mesh_queue_preq(mpath,
707                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
708         }
709         if (mpath->sn < orig_sn) {
710                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
711                                        cpu_to_le32(orig_sn),
712                                        0, NULL, 0, sdata->dev->broadcast,
713                                        hopcount, ttl, 0,
714                                        cpu_to_le32(metric + mpath->metric),
715                                        0, sdata);
716                 mpath->sn = orig_sn;
717         }
718         rcu_read_unlock();
719 }
720
721
722 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
723                             struct ieee80211_mgmt *mgmt,
724                             size_t len)
725 {
726         struct ieee802_11_elems elems;
727         size_t baselen;
728         u32 last_hop_metric;
729
730         /* need action_code */
731         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
732                 return;
733
734         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
735         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
736                         len - baselen, &elems);
737
738         if (elems.preq) {
739                 if (elems.preq_len != 37)
740                         /* Right now we support just 1 destination and no AE */
741                         return;
742                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
743                                                       MPATH_PREQ);
744                 if (last_hop_metric)
745                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
746                                                 last_hop_metric);
747         }
748         if (elems.prep) {
749                 if (elems.prep_len != 31)
750                         /* Right now we support no AE */
751                         return;
752                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
753                                                       MPATH_PREP);
754                 if (last_hop_metric)
755                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
756                                                 last_hop_metric);
757         }
758         if (elems.perr) {
759                 if (elems.perr_len != 15)
760                         /* Right now we support only one destination per PERR */
761                         return;
762                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
763         }
764         if (elems.rann)
765                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
766 }
767
768 /**
769  * mesh_queue_preq - queue a PREQ to a given destination
770  *
771  * @mpath: mesh path to discover
772  * @flags: special attributes of the PREQ to be sent
773  *
774  * Locking: the function must be called from within a rcu read lock block.
775  *
776  */
777 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
778 {
779         struct ieee80211_sub_if_data *sdata = mpath->sdata;
780         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
781         struct mesh_preq_queue *preq_node;
782
783         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
784         if (!preq_node) {
785                 mhwmp_dbg("could not allocate PREQ node\n");
786                 return;
787         }
788
789         spin_lock(&ifmsh->mesh_preq_queue_lock);
790         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
791                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
792                 kfree(preq_node);
793                 if (printk_ratelimit())
794                         mhwmp_dbg("PREQ node queue full\n");
795                 return;
796         }
797
798         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
799         preq_node->flags = flags;
800
801         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
802         ++ifmsh->preq_queue_len;
803         spin_unlock(&ifmsh->mesh_preq_queue_lock);
804
805         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
806                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
807
808         else if (time_before(jiffies, ifmsh->last_preq)) {
809                 /* avoid long wait if did not send preqs for a long time
810                  * and jiffies wrapped around
811                  */
812                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
813                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
814         } else
815                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
816                                                 min_preq_int_jiff(sdata));
817 }
818
819 /**
820  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
821  *
822  * @sdata: local mesh subif
823  */
824 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
825 {
826         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
827         struct mesh_preq_queue *preq_node;
828         struct mesh_path *mpath;
829         u8 ttl, target_flags;
830         u32 lifetime;
831
832         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
833         if (!ifmsh->preq_queue_len ||
834                 time_before(jiffies, ifmsh->last_preq +
835                                 min_preq_int_jiff(sdata))) {
836                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
837                 return;
838         }
839
840         preq_node = list_first_entry(&ifmsh->preq_queue.list,
841                         struct mesh_preq_queue, list);
842         list_del(&preq_node->list);
843         --ifmsh->preq_queue_len;
844         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
845
846         rcu_read_lock();
847         mpath = mesh_path_lookup(preq_node->dst, sdata);
848         if (!mpath)
849                 goto enddiscovery;
850
851         spin_lock_bh(&mpath->state_lock);
852         if (preq_node->flags & PREQ_Q_F_START) {
853                 if (mpath->flags & MESH_PATH_RESOLVING) {
854                         spin_unlock_bh(&mpath->state_lock);
855                         goto enddiscovery;
856                 } else {
857                         mpath->flags &= ~MESH_PATH_RESOLVED;
858                         mpath->flags |= MESH_PATH_RESOLVING;
859                         mpath->discovery_retries = 0;
860                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
861                 }
862         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
863                         mpath->flags & MESH_PATH_RESOLVED) {
864                 mpath->flags &= ~MESH_PATH_RESOLVING;
865                 spin_unlock_bh(&mpath->state_lock);
866                 goto enddiscovery;
867         }
868
869         ifmsh->last_preq = jiffies;
870
871         if (time_after(jiffies, ifmsh->last_sn_update +
872                                 net_traversal_jiffies(sdata)) ||
873             time_before(jiffies, ifmsh->last_sn_update)) {
874                 ++ifmsh->sn;
875                 sdata->u.mesh.last_sn_update = jiffies;
876         }
877         lifetime = default_lifetime(sdata);
878         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
879         if (ttl == 0) {
880                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
881                 spin_unlock_bh(&mpath->state_lock);
882                 goto enddiscovery;
883         }
884
885         if (preq_node->flags & PREQ_Q_F_REFRESH)
886                 target_flags = MP_F_DO;
887         else
888                 target_flags = MP_F_RF;
889
890         spin_unlock_bh(&mpath->state_lock);
891         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
892                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
893                         cpu_to_le32(mpath->sn), sdata->dev->broadcast, 0,
894                         ttl, cpu_to_le32(lifetime), 0,
895                         cpu_to_le32(ifmsh->preq_id++), sdata);
896         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
897
898 enddiscovery:
899         rcu_read_unlock();
900         kfree(preq_node);
901 }
902
903 /**
904  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
905  *
906  * @skb: 802.11 frame to be sent
907  * @sdata: network subif the frame will be sent through
908  *
909  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
910  * found, the function will start a path discovery and queue the frame so it is
911  * sent when the path is resolved. This means the caller must not free the skb
912  * in this case.
913  */
914 int mesh_nexthop_lookup(struct sk_buff *skb,
915                         struct ieee80211_sub_if_data *sdata)
916 {
917         struct sk_buff *skb_to_free = NULL;
918         struct mesh_path *mpath;
919         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
920         u8 *target_addr = hdr->addr3;
921         int err = 0;
922
923         rcu_read_lock();
924         mpath = mesh_path_lookup(target_addr, sdata);
925
926         if (!mpath) {
927                 mesh_path_add(target_addr, sdata);
928                 mpath = mesh_path_lookup(target_addr, sdata);
929                 if (!mpath) {
930                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
931                         err = -ENOSPC;
932                         goto endlookup;
933                 }
934         }
935
936         if (mpath->flags & MESH_PATH_ACTIVE) {
937                 if (time_after(jiffies, mpath->exp_time +
938                         msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time))
939                                 && !memcmp(sdata->dev->dev_addr, hdr->addr4,
940                                            ETH_ALEN)
941                                 && !(mpath->flags & MESH_PATH_RESOLVING)
942                                 && !(mpath->flags & MESH_PATH_FIXED)) {
943                         mesh_queue_preq(mpath,
944                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
945                 }
946                 memcpy(hdr->addr1, mpath->next_hop->sta.addr,
947                                 ETH_ALEN);
948         } else {
949                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
950                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
951                         /* Start discovery only if it is not running yet */
952                         mesh_queue_preq(mpath, PREQ_Q_F_START);
953                 }
954
955                 if (skb_queue_len(&mpath->frame_queue) >=
956                                 MESH_FRAME_QUEUE_LEN)
957                         skb_to_free = skb_dequeue(&mpath->frame_queue);
958
959                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
960                 skb_queue_tail(&mpath->frame_queue, skb);
961                 if (skb_to_free)
962                         mesh_path_discard_frame(skb_to_free, sdata);
963                 err = -ENOENT;
964         }
965
966 endlookup:
967         rcu_read_unlock();
968         return err;
969 }
970
971 void mesh_path_timer(unsigned long data)
972 {
973         struct ieee80211_sub_if_data *sdata;
974         struct mesh_path *mpath;
975
976         rcu_read_lock();
977         mpath = (struct mesh_path *) data;
978         mpath = rcu_dereference(mpath);
979         if (!mpath)
980                 goto endmpathtimer;
981         sdata = mpath->sdata;
982
983         if (sdata->local->quiescing) {
984                 rcu_read_unlock();
985                 return;
986         }
987
988         spin_lock_bh(&mpath->state_lock);
989         if (mpath->flags & MESH_PATH_RESOLVED ||
990                         (!(mpath->flags & MESH_PATH_RESOLVING)))
991                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
992         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
993                 ++mpath->discovery_retries;
994                 mpath->discovery_timeout *= 2;
995                 mesh_queue_preq(mpath, 0);
996         } else {
997                 mpath->flags = 0;
998                 mpath->exp_time = jiffies;
999                 mesh_path_flush_pending(mpath);
1000         }
1001
1002         spin_unlock_bh(&mpath->state_lock);
1003 endmpathtimer:
1004         rcu_read_unlock();
1005 }