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TOMOYO Linux Cross Reference
Linux/net/mac80211/rx.c

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  1 /*
  2  * Copyright 2002-2005, Instant802 Networks, Inc.
  3  * Copyright 2005-2006, Devicescape Software, Inc.
  4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
  5  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License version 2 as
  9  * published by the Free Software Foundation.
 10  */
 11 
 12 #include <linux/jiffies.h>
 13 #include <linux/kernel.h>
 14 #include <linux/skbuff.h>
 15 #include <linux/netdevice.h>
 16 #include <linux/etherdevice.h>
 17 #include <linux/rcupdate.h>
 18 #include <net/mac80211.h>
 19 #include <net/ieee80211_radiotap.h>
 20 
 21 #include "ieee80211_i.h"
 22 #include "driver-ops.h"
 23 #include "led.h"
 24 #include "mesh.h"
 25 #include "wep.h"
 26 #include "wpa.h"
 27 #include "tkip.h"
 28 #include "wme.h"
 29 
 30 static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
 31                                            struct tid_ampdu_rx *tid_agg_rx,
 32                                            struct sk_buff *skb,
 33                                            u16 mpdu_seq_num,
 34                                            int bar_req);
 35 /*
 36  * monitor mode reception
 37  *
 38  * This function cleans up the SKB, i.e. it removes all the stuff
 39  * only useful for monitoring.
 40  */
 41 static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
 42                                            struct sk_buff *skb,
 43                                            int rtap_len)
 44 {
 45         skb_pull(skb, rtap_len);
 46 
 47         if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
 48                 if (likely(skb->len > FCS_LEN))
 49                         skb_trim(skb, skb->len - FCS_LEN);
 50                 else {
 51                         /* driver bug */
 52                         WARN_ON(1);
 53                         dev_kfree_skb(skb);
 54                         skb = NULL;
 55                 }
 56         }
 57 
 58         return skb;
 59 }
 60 
 61 static inline int should_drop_frame(struct sk_buff *skb,
 62                                     int present_fcs_len,
 63                                     int radiotap_len)
 64 {
 65         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 66         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 67 
 68         if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
 69                 return 1;
 70         if (unlikely(skb->len < 16 + present_fcs_len + radiotap_len))
 71                 return 1;
 72         if (ieee80211_is_ctl(hdr->frame_control) &&
 73             !ieee80211_is_pspoll(hdr->frame_control) &&
 74             !ieee80211_is_back_req(hdr->frame_control))
 75                 return 1;
 76         return 0;
 77 }
 78 
 79 static int
 80 ieee80211_rx_radiotap_len(struct ieee80211_local *local,
 81                           struct ieee80211_rx_status *status)
 82 {
 83         int len;
 84 
 85         /* always present fields */
 86         len = sizeof(struct ieee80211_radiotap_header) + 9;
 87 
 88         if (status->flag & RX_FLAG_TSFT)
 89                 len += 8;
 90         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
 91                 len += 1;
 92         if (local->hw.flags & IEEE80211_HW_NOISE_DBM)
 93                 len += 1;
 94 
 95         if (len & 1) /* padding for RX_FLAGS if necessary */
 96                 len++;
 97 
 98         /* make sure radiotap starts at a naturally aligned address */
 99         if (len % 8)
100                 len = roundup(len, 8);
101 
102         return len;
103 }
104 
105 /*
106  * ieee80211_add_rx_radiotap_header - add radiotap header
107  *
108  * add a radiotap header containing all the fields which the hardware provided.
109  */
110 static void
111 ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
112                                  struct sk_buff *skb,
113                                  struct ieee80211_rate *rate,
114                                  int rtap_len)
115 {
116         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
117         struct ieee80211_radiotap_header *rthdr;
118         unsigned char *pos;
119 
120         rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
121         memset(rthdr, 0, rtap_len);
122 
123         /* radiotap header, set always present flags */
124         rthdr->it_present =
125                 cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
126                             (1 << IEEE80211_RADIOTAP_CHANNEL) |
127                             (1 << IEEE80211_RADIOTAP_ANTENNA) |
128                             (1 << IEEE80211_RADIOTAP_RX_FLAGS));
129         rthdr->it_len = cpu_to_le16(rtap_len);
130 
131         pos = (unsigned char *)(rthdr+1);
132 
133         /* the order of the following fields is important */
134 
135         /* IEEE80211_RADIOTAP_TSFT */
136         if (status->flag & RX_FLAG_TSFT) {
137                 *(__le64 *)pos = cpu_to_le64(status->mactime);
138                 rthdr->it_present |=
139                         cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
140                 pos += 8;
141         }
142 
143         /* IEEE80211_RADIOTAP_FLAGS */
144         if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
145                 *pos |= IEEE80211_RADIOTAP_F_FCS;
146         if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
147                 *pos |= IEEE80211_RADIOTAP_F_BADFCS;
148         if (status->flag & RX_FLAG_SHORTPRE)
149                 *pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
150         pos++;
151 
152         /* IEEE80211_RADIOTAP_RATE */
153         if (status->flag & RX_FLAG_HT) {
154                 /*
155                  * TODO: add following information into radiotap header once
156                  * suitable fields are defined for it:
157                  * - MCS index (status->rate_idx)
158                  * - HT40 (status->flag & RX_FLAG_40MHZ)
159                  * - short-GI (status->flag & RX_FLAG_SHORT_GI)
160                  */
161                 *pos = 0;
162         } else {
163                 rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
164                 *pos = rate->bitrate / 5;
165         }
166         pos++;
167 
168         /* IEEE80211_RADIOTAP_CHANNEL */
169         *(__le16 *)pos = cpu_to_le16(status->freq);
170         pos += 2;
171         if (status->band == IEEE80211_BAND_5GHZ)
172                 *(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_OFDM |
173                                              IEEE80211_CHAN_5GHZ);
174         else if (rate->flags & IEEE80211_RATE_ERP_G)
175                 *(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_OFDM |
176                                              IEEE80211_CHAN_2GHZ);
177         else
178                 *(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_CCK |
179                                              IEEE80211_CHAN_2GHZ);
180         pos += 2;
181 
182         /* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
183         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
184                 *pos = status->signal;
185                 rthdr->it_present |=
186                         cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
187                 pos++;
188         }
189 
190         /* IEEE80211_RADIOTAP_DBM_ANTNOISE */
191         if (local->hw.flags & IEEE80211_HW_NOISE_DBM) {
192                 *pos = status->noise;
193                 rthdr->it_present |=
194                         cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTNOISE);
195                 pos++;
196         }
197 
198         /* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
199 
200         /* IEEE80211_RADIOTAP_ANTENNA */
201         *pos = status->antenna;
202         pos++;
203 
204         /* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
205 
206         /* IEEE80211_RADIOTAP_RX_FLAGS */
207         /* ensure 2 byte alignment for the 2 byte field as required */
208         if ((pos - (unsigned char *)rthdr) & 1)
209                 pos++;
210         if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
211                 *(__le16 *)pos |= cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADPLCP);
212         pos += 2;
213 }
214 
215 /*
216  * This function copies a received frame to all monitor interfaces and
217  * returns a cleaned-up SKB that no longer includes the FCS nor the
218  * radiotap header the driver might have added.
219  */
220 static struct sk_buff *
221 ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
222                      struct ieee80211_rate *rate)
223 {
224         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
225         struct ieee80211_sub_if_data *sdata;
226         int needed_headroom = 0;
227         struct sk_buff *skb, *skb2;
228         struct net_device *prev_dev = NULL;
229         int present_fcs_len = 0;
230         int rtap_len = 0;
231 
232         /*
233          * First, we may need to make a copy of the skb because
234          *  (1) we need to modify it for radiotap (if not present), and
235          *  (2) the other RX handlers will modify the skb we got.
236          *
237          * We don't need to, of course, if we aren't going to return
238          * the SKB because it has a bad FCS/PLCP checksum.
239          */
240         if (status->flag & RX_FLAG_RADIOTAP)
241                 rtap_len = ieee80211_get_radiotap_len(origskb->data);
242         else
243                 /* room for the radiotap header based on driver features */
244                 needed_headroom = ieee80211_rx_radiotap_len(local, status);
245 
246         if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
247                 present_fcs_len = FCS_LEN;
248 
249         if (!local->monitors) {
250                 if (should_drop_frame(origskb, present_fcs_len, rtap_len)) {
251                         dev_kfree_skb(origskb);
252                         return NULL;
253                 }
254 
255                 return remove_monitor_info(local, origskb, rtap_len);
256         }
257 
258         if (should_drop_frame(origskb, present_fcs_len, rtap_len)) {
259                 /* only need to expand headroom if necessary */
260                 skb = origskb;
261                 origskb = NULL;
262 
263                 /*
264                  * This shouldn't trigger often because most devices have an
265                  * RX header they pull before we get here, and that should
266                  * be big enough for our radiotap information. We should
267                  * probably export the length to drivers so that we can have
268                  * them allocate enough headroom to start with.
269                  */
270                 if (skb_headroom(skb) < needed_headroom &&
271                     pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
272                         dev_kfree_skb(skb);
273                         return NULL;
274                 }
275         } else {
276                 /*
277                  * Need to make a copy and possibly remove radiotap header
278                  * and FCS from the original.
279                  */
280                 skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
281 
282                 origskb = remove_monitor_info(local, origskb, rtap_len);
283 
284                 if (!skb)
285                         return origskb;
286         }
287 
288         /* if necessary, prepend radiotap information */
289         if (!(status->flag & RX_FLAG_RADIOTAP))
290                 ieee80211_add_rx_radiotap_header(local, skb, rate,
291                                                  needed_headroom);
292 
293         skb_reset_mac_header(skb);
294         skb->ip_summed = CHECKSUM_UNNECESSARY;
295         skb->pkt_type = PACKET_OTHERHOST;
296         skb->protocol = htons(ETH_P_802_2);
297 
298         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
299                 if (!netif_running(sdata->dev))
300                         continue;
301 
302                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
303                         continue;
304 
305                 if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
306                         continue;
307 
308                 if (prev_dev) {
309                         skb2 = skb_clone(skb, GFP_ATOMIC);
310                         if (skb2) {
311                                 skb2->dev = prev_dev;
312                                 netif_rx(skb2);
313                         }
314                 }
315 
316                 prev_dev = sdata->dev;
317                 sdata->dev->stats.rx_packets++;
318                 sdata->dev->stats.rx_bytes += skb->len;
319         }
320 
321         if (prev_dev) {
322                 skb->dev = prev_dev;
323                 netif_rx(skb);
324         } else
325                 dev_kfree_skb(skb);
326 
327         return origskb;
328 }
329 
330 
331 static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
332 {
333         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
334         int tid;
335 
336         /* does the frame have a qos control field? */
337         if (ieee80211_is_data_qos(hdr->frame_control)) {
338                 u8 *qc = ieee80211_get_qos_ctl(hdr);
339                 /* frame has qos control */
340                 tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
341                 if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
342                         rx->flags |= IEEE80211_RX_AMSDU;
343                 else
344                         rx->flags &= ~IEEE80211_RX_AMSDU;
345         } else {
346                 /*
347                  * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
348                  *
349                  *      Sequence numbers for management frames, QoS data
350                  *      frames with a broadcast/multicast address in the
351                  *      Address 1 field, and all non-QoS data frames sent
352                  *      by QoS STAs are assigned using an additional single
353                  *      modulo-4096 counter, [...]
354                  *
355                  * We also use that counter for non-QoS STAs.
356                  */
357                 tid = NUM_RX_DATA_QUEUES - 1;
358         }
359 
360         rx->queue = tid;
361         /* Set skb->priority to 1d tag if highest order bit of TID is not set.
362          * For now, set skb->priority to 0 for other cases. */
363         rx->skb->priority = (tid > 7) ? 0 : tid;
364 }
365 
366 /**
367  * DOC: Packet alignment
368  *
369  * Drivers always need to pass packets that are aligned to two-byte boundaries
370  * to the stack.
371  *
372  * Additionally, should, if possible, align the payload data in a way that
373  * guarantees that the contained IP header is aligned to a four-byte
374  * boundary. In the case of regular frames, this simply means aligning the
375  * payload to a four-byte boundary (because either the IP header is directly
376  * contained, or IV/RFC1042 headers that have a length divisible by four are
377  * in front of it).
378  *
379  * With A-MSDU frames, however, the payload data address must yield two modulo
380  * four because there are 14-byte 802.3 headers within the A-MSDU frames that
381  * push the IP header further back to a multiple of four again. Thankfully, the
382  * specs were sane enough this time around to require padding each A-MSDU
383  * subframe to a length that is a multiple of four.
384  *
385  * Padding like Atheros hardware adds which is inbetween the 802.11 header and
386  * the payload is not supported, the driver is required to move the 802.11
387  * header to be directly in front of the payload in that case.
388  */
389 static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
390 {
391         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
392         int hdrlen;
393 
394 #ifndef CONFIG_MAC80211_DEBUG_PACKET_ALIGNMENT
395         return;
396 #endif
397 
398         if (WARN_ONCE((unsigned long)rx->skb->data & 1,
399                       "unaligned packet at 0x%p\n", rx->skb->data))
400                 return;
401 
402         if (!ieee80211_is_data_present(hdr->frame_control))
403                 return;
404 
405         hdrlen = ieee80211_hdrlen(hdr->frame_control);
406         if (rx->flags & IEEE80211_RX_AMSDU)
407                 hdrlen += ETH_HLEN;
408         WARN_ONCE(((unsigned long)(rx->skb->data + hdrlen)) & 3,
409                   "unaligned IP payload at 0x%p\n", rx->skb->data + hdrlen);
410 }
411 
412 
413 /* rx handlers */
414 
415 static ieee80211_rx_result debug_noinline
416 ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
417 {
418         struct ieee80211_local *local = rx->local;
419         struct sk_buff *skb = rx->skb;
420 
421         if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning)))
422                 return ieee80211_scan_rx(rx->sdata, skb);
423 
424         if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning) &&
425                      (rx->flags & IEEE80211_RX_IN_SCAN))) {
426                 /* drop all the other packets during a software scan anyway */
427                 if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
428                         dev_kfree_skb(skb);
429                 return RX_QUEUED;
430         }
431 
432         if (unlikely(rx->flags & IEEE80211_RX_IN_SCAN)) {
433                 /* scanning finished during invoking of handlers */
434                 I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
435                 return RX_DROP_UNUSABLE;
436         }
437 
438         return RX_CONTINUE;
439 }
440 
441 
442 static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
443 {
444         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
445 
446         if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
447                 return 0;
448 
449         return ieee80211_is_robust_mgmt_frame(hdr);
450 }
451 
452 
453 static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
454 {
455         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
456 
457         if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
458                 return 0;
459 
460         return ieee80211_is_robust_mgmt_frame(hdr);
461 }
462 
463 
464 /* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
465 static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
466 {
467         struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
468         struct ieee80211_mmie *mmie;
469 
470         if (skb->len < 24 + sizeof(*mmie) ||
471             !is_multicast_ether_addr(hdr->da))
472                 return -1;
473 
474         if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
475                 return -1; /* not a robust management frame */
476 
477         mmie = (struct ieee80211_mmie *)
478                 (skb->data + skb->len - sizeof(*mmie));
479         if (mmie->element_id != WLAN_EID_MMIE ||
480             mmie->length != sizeof(*mmie) - 2)
481                 return -1;
482 
483         return le16_to_cpu(mmie->key_id);
484 }
485 
486 
487 static ieee80211_rx_result
488 ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
489 {
490         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
491         unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
492         char *dev_addr = rx->dev->dev_addr;
493 
494         if (ieee80211_is_data(hdr->frame_control)) {
495                 if (is_multicast_ether_addr(hdr->addr1)) {
496                         if (ieee80211_has_tods(hdr->frame_control) ||
497                                 !ieee80211_has_fromds(hdr->frame_control))
498                                 return RX_DROP_MONITOR;
499                         if (memcmp(hdr->addr3, dev_addr, ETH_ALEN) == 0)
500                                 return RX_DROP_MONITOR;
501                 } else {
502                         if (!ieee80211_has_a4(hdr->frame_control))
503                                 return RX_DROP_MONITOR;
504                         if (memcmp(hdr->addr4, dev_addr, ETH_ALEN) == 0)
505                                 return RX_DROP_MONITOR;
506                 }
507         }
508 
509         /* If there is not an established peer link and this is not a peer link
510          * establisment frame, beacon or probe, drop the frame.
511          */
512 
513         if (!rx->sta || sta_plink_state(rx->sta) != PLINK_ESTAB) {
514                 struct ieee80211_mgmt *mgmt;
515 
516                 if (!ieee80211_is_mgmt(hdr->frame_control))
517                         return RX_DROP_MONITOR;
518 
519                 if (ieee80211_is_action(hdr->frame_control)) {
520                         mgmt = (struct ieee80211_mgmt *)hdr;
521                         if (mgmt->u.action.category != PLINK_CATEGORY)
522                                 return RX_DROP_MONITOR;
523                         return RX_CONTINUE;
524                 }
525 
526                 if (ieee80211_is_probe_req(hdr->frame_control) ||
527                     ieee80211_is_probe_resp(hdr->frame_control) ||
528                     ieee80211_is_beacon(hdr->frame_control))
529                         return RX_CONTINUE;
530 
531                 return RX_DROP_MONITOR;
532 
533         }
534 
535 #define msh_h_get(h, l) ((struct ieee80211s_hdr *) ((u8 *)h + l))
536 
537         if (ieee80211_is_data(hdr->frame_control) &&
538             is_multicast_ether_addr(hdr->addr1) &&
539             mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
540                 return RX_DROP_MONITOR;
541 #undef msh_h_get
542 
543         return RX_CONTINUE;
544 }
545 
546 
547 static ieee80211_rx_result debug_noinline
548 ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
549 {
550         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
551 
552         /* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
553         if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
554                 if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
555                              rx->sta->last_seq_ctrl[rx->queue] ==
556                              hdr->seq_ctrl)) {
557                         if (rx->flags & IEEE80211_RX_RA_MATCH) {
558                                 rx->local->dot11FrameDuplicateCount++;
559                                 rx->sta->num_duplicates++;
560                         }
561                         return RX_DROP_MONITOR;
562                 } else
563                         rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
564         }
565 
566         if (unlikely(rx->skb->len < 16)) {
567                 I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
568                 return RX_DROP_MONITOR;
569         }
570 
571         /* Drop disallowed frame classes based on STA auth/assoc state;
572          * IEEE 802.11, Chap 5.5.
573          *
574          * mac80211 filters only based on association state, i.e. it drops
575          * Class 3 frames from not associated stations. hostapd sends
576          * deauth/disassoc frames when needed. In addition, hostapd is
577          * responsible for filtering on both auth and assoc states.
578          */
579 
580         if (ieee80211_vif_is_mesh(&rx->sdata->vif))
581                 return ieee80211_rx_mesh_check(rx);
582 
583         if (unlikely((ieee80211_is_data(hdr->frame_control) ||
584                       ieee80211_is_pspoll(hdr->frame_control)) &&
585                      rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
586                      (!rx->sta || !test_sta_flags(rx->sta, WLAN_STA_ASSOC)))) {
587                 if ((!ieee80211_has_fromds(hdr->frame_control) &&
588                      !ieee80211_has_tods(hdr->frame_control) &&
589                      ieee80211_is_data(hdr->frame_control)) ||
590                     !(rx->flags & IEEE80211_RX_RA_MATCH)) {
591                         /* Drop IBSS frames and frames for other hosts
592                          * silently. */
593                         return RX_DROP_MONITOR;
594                 }
595 
596                 return RX_DROP_MONITOR;
597         }
598 
599         return RX_CONTINUE;
600 }
601 
602 
603 static ieee80211_rx_result debug_noinline
604 ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
605 {
606         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
607         int keyidx;
608         int hdrlen;
609         ieee80211_rx_result result = RX_DROP_UNUSABLE;
610         struct ieee80211_key *stakey = NULL;
611         int mmie_keyidx = -1;
612 
613         /*
614          * Key selection 101
615          *
616          * There are four types of keys:
617          *  - GTK (group keys)
618          *  - IGTK (group keys for management frames)
619          *  - PTK (pairwise keys)
620          *  - STK (station-to-station pairwise keys)
621          *
622          * When selecting a key, we have to distinguish between multicast
623          * (including broadcast) and unicast frames, the latter can only
624          * use PTKs and STKs while the former always use GTKs and IGTKs.
625          * Unless, of course, actual WEP keys ("pre-RSNA") are used, then
626          * unicast frames can also use key indices like GTKs. Hence, if we
627          * don't have a PTK/STK we check the key index for a WEP key.
628          *
629          * Note that in a regular BSS, multicast frames are sent by the
630          * AP only, associated stations unicast the frame to the AP first
631          * which then multicasts it on their behalf.
632          *
633          * There is also a slight problem in IBSS mode: GTKs are negotiated
634          * with each station, that is something we don't currently handle.
635          * The spec seems to expect that one negotiates the same key with
636          * every station but there's no such requirement; VLANs could be
637          * possible.
638          */
639 
640         /*
641          * No point in finding a key and decrypting if the frame is neither
642          * addressed to us nor a multicast frame.
643          */
644         if (!(rx->flags & IEEE80211_RX_RA_MATCH))
645                 return RX_CONTINUE;
646 
647         if (rx->sta)
648                 stakey = rcu_dereference(rx->sta->key);
649 
650         if (!ieee80211_has_protected(hdr->frame_control))
651                 mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
652 
653         if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
654                 rx->key = stakey;
655                 /* Skip decryption if the frame is not protected. */
656                 if (!ieee80211_has_protected(hdr->frame_control))
657                         return RX_CONTINUE;
658         } else if (mmie_keyidx >= 0) {
659                 /* Broadcast/multicast robust management frame / BIP */
660                 if ((rx->status->flag & RX_FLAG_DECRYPTED) &&
661                     (rx->status->flag & RX_FLAG_IV_STRIPPED))
662                         return RX_CONTINUE;
663 
664                 if (mmie_keyidx < NUM_DEFAULT_KEYS ||
665                     mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
666                         return RX_DROP_MONITOR; /* unexpected BIP keyidx */
667                 rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
668         } else if (!ieee80211_has_protected(hdr->frame_control)) {
669                 /*
670                  * The frame was not protected, so skip decryption. However, we
671                  * need to set rx->key if there is a key that could have been
672                  * used so that the frame may be dropped if encryption would
673                  * have been expected.
674                  */
675                 struct ieee80211_key *key = NULL;
676                 if (ieee80211_is_mgmt(hdr->frame_control) &&
677                     is_multicast_ether_addr(hdr->addr1) &&
678                     (key = rcu_dereference(rx->sdata->default_mgmt_key)))
679                         rx->key = key;
680                 else if ((key = rcu_dereference(rx->sdata->default_key)))
681                         rx->key = key;
682                 return RX_CONTINUE;
683         } else {
684                 /*
685                  * The device doesn't give us the IV so we won't be
686                  * able to look up the key. That's ok though, we
687                  * don't need to decrypt the frame, we just won't
688                  * be able to keep statistics accurate.
689                  * Except for key threshold notifications, should
690                  * we somehow allow the driver to tell us which key
691                  * the hardware used if this flag is set?
692                  */
693                 if ((rx->status->flag & RX_FLAG_DECRYPTED) &&
694                     (rx->status->flag & RX_FLAG_IV_STRIPPED))
695                         return RX_CONTINUE;
696 
697                 hdrlen = ieee80211_hdrlen(hdr->frame_control);
698 
699                 if (rx->skb->len < 8 + hdrlen)
700                         return RX_DROP_UNUSABLE; /* TODO: count this? */
701 
702                 /*
703                  * no need to call ieee80211_wep_get_keyidx,
704                  * it verifies a bunch of things we've done already
705                  */
706                 keyidx = rx->skb->data[hdrlen + 3] >> 6;
707 
708                 rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
709 
710                 /*
711                  * RSNA-protected unicast frames should always be sent with
712                  * pairwise or station-to-station keys, but for WEP we allow
713                  * using a key index as well.
714                  */
715                 if (rx->key && rx->key->conf.alg != ALG_WEP &&
716                     !is_multicast_ether_addr(hdr->addr1))
717                         rx->key = NULL;
718         }
719 
720         if (rx->key) {
721                 rx->key->tx_rx_count++;
722                 /* TODO: add threshold stuff again */
723         } else {
724                 return RX_DROP_MONITOR;
725         }
726 
727         /* Check for weak IVs if possible */
728         if (rx->sta && rx->key->conf.alg == ALG_WEP &&
729             ieee80211_is_data(hdr->frame_control) &&
730             (!(rx->status->flag & RX_FLAG_IV_STRIPPED) ||
731              !(rx->status->flag & RX_FLAG_DECRYPTED)) &&
732             ieee80211_wep_is_weak_iv(rx->skb, rx->key))
733                 rx->sta->wep_weak_iv_count++;
734 
735         switch (rx->key->conf.alg) {
736         case ALG_WEP:
737                 result = ieee80211_crypto_wep_decrypt(rx);
738                 break;
739         case ALG_TKIP:
740                 result = ieee80211_crypto_tkip_decrypt(rx);
741                 break;
742         case ALG_CCMP:
743                 result = ieee80211_crypto_ccmp_decrypt(rx);
744                 break;
745         case ALG_AES_CMAC:
746                 result = ieee80211_crypto_aes_cmac_decrypt(rx);
747                 break;
748         }
749 
750         /* either the frame has been decrypted or will be dropped */
751         rx->status->flag |= RX_FLAG_DECRYPTED;
752 
753         return result;
754 }
755 
756 static ieee80211_rx_result debug_noinline
757 ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
758 {
759         struct ieee80211_local *local;
760         struct ieee80211_hdr *hdr;
761         struct sk_buff *skb;
762 
763         local = rx->local;
764         skb = rx->skb;
765         hdr = (struct ieee80211_hdr *) skb->data;
766 
767         if (!local->pspolling)
768                 return RX_CONTINUE;
769 
770         if (!ieee80211_has_fromds(hdr->frame_control))
771                 /* this is not from AP */
772                 return RX_CONTINUE;
773 
774         if (!ieee80211_is_data(hdr->frame_control))
775                 return RX_CONTINUE;
776 
777         if (!ieee80211_has_moredata(hdr->frame_control)) {
778                 /* AP has no more frames buffered for us */
779                 local->pspolling = false;
780                 return RX_CONTINUE;
781         }
782 
783         /* more data bit is set, let's request a new frame from the AP */
784         ieee80211_send_pspoll(local, rx->sdata);
785 
786         return RX_CONTINUE;
787 }
788 
789 static void ap_sta_ps_start(struct sta_info *sta)
790 {
791         struct ieee80211_sub_if_data *sdata = sta->sdata;
792         struct ieee80211_local *local = sdata->local;
793 
794         atomic_inc(&sdata->bss->num_sta_ps);
795         set_sta_flags(sta, WLAN_STA_PS);
796         drv_sta_notify(local, &sdata->vif, STA_NOTIFY_SLEEP, &sta->sta);
797 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
798         printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
799                sdata->dev->name, sta->sta.addr, sta->sta.aid);
800 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
801 }
802 
803 static int ap_sta_ps_end(struct sta_info *sta)
804 {
805         struct ieee80211_sub_if_data *sdata = sta->sdata;
806         struct ieee80211_local *local = sdata->local;
807         int sent, buffered;
808 
809         atomic_dec(&sdata->bss->num_sta_ps);
810 
811         clear_sta_flags(sta, WLAN_STA_PS);
812         drv_sta_notify(local, &sdata->vif, STA_NOTIFY_AWAKE, &sta->sta);
813 
814         if (!skb_queue_empty(&sta->ps_tx_buf))
815                 sta_info_clear_tim_bit(sta);
816 
817 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
818         printk(KERN_DEBUG "%s: STA %pM aid %d exits power save mode\n",
819                sdata->dev->name, sta->sta.addr, sta->sta.aid);
820 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
821 
822         /* Send all buffered frames to the station */
823         sent = ieee80211_add_pending_skbs(local, &sta->tx_filtered);
824         buffered = ieee80211_add_pending_skbs(local, &sta->ps_tx_buf);
825         sent += buffered;
826         local->total_ps_buffered -= buffered;
827 
828 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
829         printk(KERN_DEBUG "%s: STA %pM aid %d sending %d filtered/%d PS frames "
830                "since STA not sleeping anymore\n", sdata->dev->name,
831                sta->sta.addr, sta->sta.aid, sent - buffered, buffered);
832 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
833 
834         return sent;
835 }
836 
837 static ieee80211_rx_result debug_noinline
838 ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
839 {
840         struct sta_info *sta = rx->sta;
841         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
842 
843         if (!sta)
844                 return RX_CONTINUE;
845 
846         /*
847          * Update last_rx only for IBSS packets which are for the current
848          * BSSID to avoid keeping the current IBSS network alive in cases
849          * where other STAs start using different BSSID.
850          */
851         if (rx->sdata->vif.type == NL80211_IFTYPE_ADHOC) {
852                 u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
853                                                 NL80211_IFTYPE_ADHOC);
854                 if (compare_ether_addr(bssid, rx->sdata->u.ibss.bssid) == 0)
855                         sta->last_rx = jiffies;
856         } else if (!is_multicast_ether_addr(hdr->addr1)) {
857                 /*
858                  * Mesh beacons will update last_rx when if they are found to
859                  * match the current local configuration when processed.
860                  */
861                 sta->last_rx = jiffies;
862         }
863 
864         if (!(rx->flags & IEEE80211_RX_RA_MATCH))
865                 return RX_CONTINUE;
866 
867         if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)
868                 ieee80211_sta_rx_notify(rx->sdata, hdr);
869 
870         sta->rx_fragments++;
871         sta->rx_bytes += rx->skb->len;
872         sta->last_signal = rx->status->signal;
873         sta->last_qual = rx->status->qual;
874         sta->last_noise = rx->status->noise;
875 
876         /*
877          * Change STA power saving mode only at the end of a frame
878          * exchange sequence.
879          */
880         if (!ieee80211_has_morefrags(hdr->frame_control) &&
881             (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
882              rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)) {
883                 if (test_sta_flags(sta, WLAN_STA_PS)) {
884                         /*
885                          * Ignore doze->wake transitions that are
886                          * indicated by non-data frames, the standard
887                          * is unclear here, but for example going to
888                          * PS mode and then scanning would cause a
889                          * doze->wake transition for the probe request,
890                          * and that is clearly undesirable.
891                          */
892                         if (ieee80211_is_data(hdr->frame_control) &&
893                             !ieee80211_has_pm(hdr->frame_control))
894                                 rx->sent_ps_buffered += ap_sta_ps_end(sta);
895                 } else {
896                         if (ieee80211_has_pm(hdr->frame_control))
897                                 ap_sta_ps_start(sta);
898                 }
899         }
900 
901         /* Drop data::nullfunc frames silently, since they are used only to
902          * control station power saving mode. */
903         if (ieee80211_is_nullfunc(hdr->frame_control)) {
904                 I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
905                 /* Update counter and free packet here to avoid counting this
906                  * as a dropped packed. */
907                 sta->rx_packets++;
908                 dev_kfree_skb(rx->skb);
909                 return RX_QUEUED;
910         }
911 
912         return RX_CONTINUE;
913 } /* ieee80211_rx_h_sta_process */
914 
915 static inline struct ieee80211_fragment_entry *
916 ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata,
917                          unsigned int frag, unsigned int seq, int rx_queue,
918                          struct sk_buff **skb)
919 {
920         struct ieee80211_fragment_entry *entry;
921         int idx;
922 
923         idx = sdata->fragment_next;
924         entry = &sdata->fragments[sdata->fragment_next++];
925         if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX)
926                 sdata->fragment_next = 0;
927 
928         if (!skb_queue_empty(&entry->skb_list)) {
929 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
930                 struct ieee80211_hdr *hdr =
931                         (struct ieee80211_hdr *) entry->skb_list.next->data;
932                 printk(KERN_DEBUG "%s: RX reassembly removed oldest "
933                        "fragment entry (idx=%d age=%lu seq=%d last_frag=%d "
934                        "addr1=%pM addr2=%pM\n",
935                        sdata->dev->name, idx,
936                        jiffies - entry->first_frag_time, entry->seq,
937                        entry->last_frag, hdr->addr1, hdr->addr2);
938 #endif
939                 __skb_queue_purge(&entry->skb_list);
940         }
941 
942         __skb_queue_tail(&entry->skb_list, *skb); /* no need for locking */
943         *skb = NULL;
944         entry->first_frag_time = jiffies;
945         entry->seq = seq;
946         entry->rx_queue = rx_queue;
947         entry->last_frag = frag;
948         entry->ccmp = 0;
949         entry->extra_len = 0;
950 
951         return entry;
952 }
953 
954 static inline struct ieee80211_fragment_entry *
955 ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata,
956                           unsigned int frag, unsigned int seq,
957                           int rx_queue, struct ieee80211_hdr *hdr)
958 {
959         struct ieee80211_fragment_entry *entry;
960         int i, idx;
961 
962         idx = sdata->fragment_next;
963         for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) {
964                 struct ieee80211_hdr *f_hdr;
965 
966                 idx--;
967                 if (idx < 0)
968                         idx = IEEE80211_FRAGMENT_MAX - 1;
969 
970                 entry = &sdata->fragments[idx];
971                 if (skb_queue_empty(&entry->skb_list) || entry->seq != seq ||
972                     entry->rx_queue != rx_queue ||
973                     entry->last_frag + 1 != frag)
974                         continue;
975 
976                 f_hdr = (struct ieee80211_hdr *)entry->skb_list.next->data;
977 
978                 /*
979                  * Check ftype and addresses are equal, else check next fragment
980                  */
981                 if (((hdr->frame_control ^ f_hdr->frame_control) &
982                      cpu_to_le16(IEEE80211_FCTL_FTYPE)) ||
983                     compare_ether_addr(hdr->addr1, f_hdr->addr1) != 0 ||
984                     compare_ether_addr(hdr->addr2, f_hdr->addr2) != 0)
985                         continue;
986 
987                 if (time_after(jiffies, entry->first_frag_time + 2 * HZ)) {
988                         __skb_queue_purge(&entry->skb_list);
989                         continue;
990                 }
991                 return entry;
992         }
993 
994         return NULL;
995 }
996 
997 static ieee80211_rx_result debug_noinline
998 ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
999 {
1000         struct ieee80211_hdr *hdr;
1001         u16 sc;
1002         __le16 fc;
1003         unsigned int frag, seq;
1004         struct ieee80211_fragment_entry *entry;
1005         struct sk_buff *skb;
1006 
1007         hdr = (struct ieee80211_hdr *)rx->skb->data;
1008         fc = hdr->frame_control;
1009         sc = le16_to_cpu(hdr->seq_ctrl);
1010         frag = sc & IEEE80211_SCTL_FRAG;
1011 
1012         if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
1013                    (rx->skb)->len < 24 ||
1014                    is_multicast_ether_addr(hdr->addr1))) {
1015                 /* not fragmented */
1016                 goto out;
1017         }
1018         I802_DEBUG_INC(rx->local->rx_handlers_fragments);
1019 
1020         seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
1021 
1022         if (frag == 0) {
1023                 /* This is the first fragment of a new frame. */
1024                 entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
1025                                                  rx->queue, &(rx->skb));
1026                 if (rx->key && rx->key->conf.alg == ALG_CCMP &&
1027                     ieee80211_has_protected(fc)) {
1028                         /* Store CCMP PN so that we can verify that the next
1029                          * fragment has a sequential PN value. */
1030                         entry->ccmp = 1;
1031                         memcpy(entry->last_pn,
1032                                rx->key->u.ccmp.rx_pn[rx->queue],
1033                                CCMP_PN_LEN);
1034                 }
1035                 return RX_QUEUED;
1036         }
1037 
1038         /* This is a fragment for a frame that should already be pending in
1039          * fragment cache. Add this fragment to the end of the pending entry.
1040          */
1041         entry = ieee80211_reassemble_find(rx->sdata, frag, seq, rx->queue, hdr);
1042         if (!entry) {
1043                 I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
1044                 return RX_DROP_MONITOR;
1045         }
1046 
1047         /* Verify that MPDUs within one MSDU have sequential PN values.
1048          * (IEEE 802.11i, 8.3.3.4.5) */
1049         if (entry->ccmp) {
1050                 int i;
1051                 u8 pn[CCMP_PN_LEN], *rpn;
1052                 if (!rx->key || rx->key->conf.alg != ALG_CCMP)
1053                         return RX_DROP_UNUSABLE;
1054                 memcpy(pn, entry->last_pn, CCMP_PN_LEN);
1055                 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
1056                         pn[i]++;
1057                         if (pn[i])
1058                                 break;
1059                 }
1060                 rpn = rx->key->u.ccmp.rx_pn[rx->queue];
1061                 if (memcmp(pn, rpn, CCMP_PN_LEN))
1062                         return RX_DROP_UNUSABLE;
1063                 memcpy(entry->last_pn, pn, CCMP_PN_LEN);
1064         }
1065 
1066         skb_pull(rx->skb, ieee80211_hdrlen(fc));
1067         __skb_queue_tail(&entry->skb_list, rx->skb);
1068         entry->last_frag = frag;
1069         entry->extra_len += rx->skb->len;
1070         if (ieee80211_has_morefrags(fc)) {
1071                 rx->skb = NULL;
1072                 return RX_QUEUED;
1073         }
1074 
1075         rx->skb = __skb_dequeue(&entry->skb_list);
1076         if (skb_tailroom(rx->skb) < entry->extra_len) {
1077                 I802_DEBUG_INC(rx->local->rx_expand_skb_head2);
1078                 if (unlikely(pskb_expand_head(rx->skb, 0, entry->extra_len,
1079                                               GFP_ATOMIC))) {
1080                         I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
1081                         __skb_queue_purge(&entry->skb_list);
1082                         return RX_DROP_UNUSABLE;
1083                 }
1084         }
1085         while ((skb = __skb_dequeue(&entry->skb_list))) {
1086                 memcpy(skb_put(rx->skb, skb->len), skb->data, skb->len);
1087                 dev_kfree_skb(skb);
1088         }
1089 
1090         /* Complete frame has been reassembled - process it now */
1091         rx->flags |= IEEE80211_RX_FRAGMENTED;
1092 
1093  out:
1094         if (rx->sta)
1095                 rx->sta->rx_packets++;
1096         if (is_multicast_ether_addr(hdr->addr1))
1097                 rx->local->dot11MulticastReceivedFrameCount++;
1098         else
1099                 ieee80211_led_rx(rx->local);
1100         return RX_CONTINUE;
1101 }
1102 
1103 static ieee80211_rx_result debug_noinline
1104 ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
1105 {
1106         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(rx->dev);
1107         struct sk_buff *skb;
1108         int no_pending_pkts;
1109         __le16 fc = ((struct ieee80211_hdr *)rx->skb->data)->frame_control;
1110 
1111         if (likely(!rx->sta || !ieee80211_is_pspoll(fc) ||
1112                    !(rx->flags & IEEE80211_RX_RA_MATCH)))
1113                 return RX_CONTINUE;
1114 
1115         if ((sdata->vif.type != NL80211_IFTYPE_AP) &&
1116             (sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
1117                 return RX_DROP_UNUSABLE;
1118 
1119         skb = skb_dequeue(&rx->sta->tx_filtered);
1120         if (!skb) {
1121                 skb = skb_dequeue(&rx->sta->ps_tx_buf);
1122                 if (skb)
1123                         rx->local->total_ps_buffered--;
1124         }
1125         no_pending_pkts = skb_queue_empty(&rx->sta->tx_filtered) &&
1126                 skb_queue_empty(&rx->sta->ps_tx_buf);
1127 
1128         if (skb) {
1129                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1130                 struct ieee80211_hdr *hdr =
1131                         (struct ieee80211_hdr *) skb->data;
1132 
1133                 /*
1134                  * Tell TX path to send this frame even though the STA may
1135                  * still remain is PS mode after this frame exchange.
1136                  */
1137                 info->flags |= IEEE80211_TX_CTL_PSPOLL_RESPONSE;
1138 
1139 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1140                 printk(KERN_DEBUG "STA %pM aid %d: PS Poll (entries after %d)\n",
1141                        rx->sta->sta.addr, rx->sta->sta.aid,
1142                        skb_queue_len(&rx->sta->ps_tx_buf));
1143 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1144 
1145                 /* Use MoreData flag to indicate whether there are more
1146                  * buffered frames for this STA */
1147                 if (no_pending_pkts)
1148                         hdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
1149                 else
1150                         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREDATA);
1151 
1152                 ieee80211_add_pending_skb(rx->local, skb);
1153 
1154                 if (no_pending_pkts)
1155                         sta_info_clear_tim_bit(rx->sta);
1156 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1157         } else if (!rx->sent_ps_buffered) {
1158                 /*
1159                  * FIXME: This can be the result of a race condition between
1160                  *        us expiring a frame and the station polling for it.
1161                  *        Should we send it a null-func frame indicating we
1162                  *        have nothing buffered for it?
1163                  */
1164                 printk(KERN_DEBUG "%s: STA %pM sent PS Poll even "
1165                        "though there are no buffered frames for it\n",
1166                        rx->dev->name, rx->sta->sta.addr);
1167 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1168         }
1169 
1170         /* Free PS Poll skb here instead of returning RX_DROP that would
1171          * count as an dropped frame. */
1172         dev_kfree_skb(rx->skb);
1173 
1174         return RX_QUEUED;
1175 }
1176 
1177 static ieee80211_rx_result debug_noinline
1178 ieee80211_rx_h_remove_qos_control(struct ieee80211_rx_data *rx)
1179 {
1180         u8 *data = rx->skb->data;
1181         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)data;
1182 
1183         if (!ieee80211_is_data_qos(hdr->frame_control))
1184                 return RX_CONTINUE;
1185 
1186         /* remove the qos control field, update frame type and meta-data */
1187         memmove(data + IEEE80211_QOS_CTL_LEN, data,
1188                 ieee80211_hdrlen(hdr->frame_control) - IEEE80211_QOS_CTL_LEN);
1189         hdr = (struct ieee80211_hdr *)skb_pull(rx->skb, IEEE80211_QOS_CTL_LEN);
1190         /* change frame type to non QOS */
1191         hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
1192 
1193         return RX_CONTINUE;
1194 }
1195 
1196 static int
1197 ieee80211_802_1x_port_control(struct ieee80211_rx_data *rx)
1198 {
1199         if (unlikely(!rx->sta ||
1200             !test_sta_flags(rx->sta, WLAN_STA_AUTHORIZED)))
1201                 return -EACCES;
1202 
1203         return 0;
1204 }
1205 
1206 static int
1207 ieee80211_drop_unencrypted(struct ieee80211_rx_data *rx, __le16 fc)
1208 {
1209         /*
1210          * Pass through unencrypted frames if the hardware has
1211          * decrypted them already.
1212          */
1213         if (rx->status->flag & RX_FLAG_DECRYPTED)
1214                 return 0;
1215 
1216         /* Drop unencrypted frames if key is set. */
1217         if (unlikely(!ieee80211_has_protected(fc) &&
1218                      !ieee80211_is_nullfunc(fc) &&
1219                      ieee80211_is_data(fc) &&
1220                      (rx->key || rx->sdata->drop_unencrypted)))
1221                 return -EACCES;
1222         if (rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP)) {
1223                 if (unlikely(!ieee80211_has_protected(fc) &&
1224                              ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
1225                              rx->key))
1226                         return -EACCES;
1227                 /* BIP does not use Protected field, so need to check MMIE */
1228                 if (unlikely(ieee80211_is_multicast_robust_mgmt_frame(rx->skb)
1229                              && ieee80211_get_mmie_keyidx(rx->skb) < 0 &&
1230                              rx->key))
1231                         return -EACCES;
1232                 /*
1233                  * When using MFP, Action frames are not allowed prior to
1234                  * having configured keys.
1235                  */
1236                 if (unlikely(ieee80211_is_action(fc) && !rx->key &&
1237                              ieee80211_is_robust_mgmt_frame(
1238                                      (struct ieee80211_hdr *) rx->skb->data)))
1239                         return -EACCES;
1240         }
1241 
1242         return 0;
1243 }
1244 
1245 static int
1246 __ieee80211_data_to_8023(struct ieee80211_rx_data *rx)
1247 {
1248         struct net_device *dev = rx->dev;
1249         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
1250 
1251         return ieee80211_data_to_8023(rx->skb, dev->dev_addr, sdata->vif.type);
1252 }
1253 
1254 /*
1255  * requires that rx->skb is a frame with ethernet header
1256  */
1257 static bool ieee80211_frame_allowed(struct ieee80211_rx_data *rx, __le16 fc)
1258 {
1259         static const u8 pae_group_addr[ETH_ALEN] __aligned(2)
1260                 = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x03 };
1261         struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
1262 
1263         /*
1264          * Allow EAPOL frames to us/the PAE group address regardless
1265          * of whether the frame was encrypted or not.
1266          */
1267         if (ehdr->h_proto == htons(ETH_P_PAE) &&
1268             (compare_ether_addr(ehdr->h_dest, rx->dev->dev_addr) == 0 ||
1269              compare_ether_addr(ehdr->h_dest, pae_group_addr) == 0))
1270                 return true;
1271 
1272         if (ieee80211_802_1x_port_control(rx) ||
1273             ieee80211_drop_unencrypted(rx, fc))
1274                 return false;
1275 
1276         return true;
1277 }
1278 
1279 /*
1280  * requires that rx->skb is a frame with ethernet header
1281  */
1282 static void
1283 ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
1284 {
1285         struct net_device *dev = rx->dev;
1286         struct ieee80211_local *local = rx->local;
1287         struct sk_buff *skb, *xmit_skb;
1288         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
1289         struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
1290         struct sta_info *dsta;
1291 
1292         skb = rx->skb;
1293         xmit_skb = NULL;
1294 
1295         if ((sdata->vif.type == NL80211_IFTYPE_AP ||
1296              sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
1297             !(sdata->flags & IEEE80211_SDATA_DONT_BRIDGE_PACKETS) &&
1298             (rx->flags & IEEE80211_RX_RA_MATCH)) {
1299                 if (is_multicast_ether_addr(ehdr->h_dest)) {
1300                         /*
1301                          * send multicast frames both to higher layers in
1302                          * local net stack and back to the wireless medium
1303                          */
1304                         xmit_skb = skb_copy(skb, GFP_ATOMIC);
1305                         if (!xmit_skb && net_ratelimit())
1306                                 printk(KERN_DEBUG "%s: failed to clone "
1307                                        "multicast frame\n", dev->name);
1308                 } else {
1309                         dsta = sta_info_get(local, skb->data);
1310                         if (dsta && dsta->sdata->dev == dev) {
1311                                 /*
1312                                  * The destination station is associated to
1313                                  * this AP (in this VLAN), so send the frame
1314                                  * directly to it and do not pass it to local
1315                                  * net stack.
1316                                  */
1317                                 xmit_skb = skb;
1318                                 skb = NULL;
1319                         }
1320                 }
1321         }
1322 
1323         if (skb) {
1324                 int align __maybe_unused;
1325 
1326 #if defined(CONFIG_MAC80211_DEBUG_PACKET_ALIGNMENT) || !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
1327                 /*
1328                  * 'align' will only take the values 0 or 2 here
1329                  * since all frames are required to be aligned
1330                  * to 2-byte boundaries when being passed to
1331                  * mac80211. That also explains the __skb_push()
1332                  * below.
1333                  */
1334                 align = ((unsigned long)(skb->data + sizeof(struct ethhdr))) & 3;
1335                 if (align) {
1336                         if (WARN_ON(skb_headroom(skb) < 3)) {
1337                                 dev_kfree_skb(skb);
1338                                 skb = NULL;
1339                         } else {
1340                                 u8 *data = skb->data;
1341                                 size_t len = skb->len;
1342                                 u8 *new = __skb_push(skb, align);
1343                                 memmove(new, data, len);
1344                                 __skb_trim(skb, len);
1345                         }
1346                 }
1347 #endif
1348 
1349                 if (skb) {
1350                         /* deliver to local stack */
1351                         skb->protocol = eth_type_trans(skb, dev);
1352                         memset(skb->cb, 0, sizeof(skb->cb));
1353                         netif_rx(skb);
1354                 }
1355         }
1356 
1357         if (xmit_skb) {
1358                 /* send to wireless media */
1359                 xmit_skb->protocol = htons(ETH_P_802_3);
1360                 skb_reset_network_header(xmit_skb);
1361                 skb_reset_mac_header(xmit_skb);
1362                 dev_queue_xmit(xmit_skb);
1363         }
1364 }
1365 
1366 static ieee80211_rx_result debug_noinline
1367 ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
1368 {
1369         struct net_device *dev = rx->dev;
1370         struct ieee80211_local *local = rx->local;
1371         u16 ethertype;
1372         u8 *payload;
1373         struct sk_buff *skb = rx->skb, *frame = NULL;
1374         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1375         __le16 fc = hdr->frame_control;
1376         const struct ethhdr *eth;
1377         int remaining, err;
1378         u8 dst[ETH_ALEN];
1379         u8 src[ETH_ALEN];
1380 
1381         if (unlikely(!ieee80211_is_data(fc)))
1382                 return RX_CONTINUE;
1383 
1384         if (unlikely(!ieee80211_is_data_present(fc)))
1385                 return RX_DROP_MONITOR;
1386 
1387         if (!(rx->flags & IEEE80211_RX_AMSDU))
1388                 return RX_CONTINUE;
1389 
1390         err = __ieee80211_data_to_8023(rx);
1391         if (unlikely(err))
1392                 return RX_DROP_UNUSABLE;
1393 
1394         skb->dev = dev;
1395 
1396         dev->stats.rx_packets++;
1397         dev->stats.rx_bytes += skb->len;
1398 
1399         /* skip the wrapping header */
1400         eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
1401         if (!eth)
1402                 return RX_DROP_UNUSABLE;
1403 
1404         while (skb != frame) {
1405                 u8 padding;
1406                 __be16 len = eth->h_proto;
1407                 unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
1408 
1409                 remaining = skb->len;
1410                 memcpy(dst, eth->h_dest, ETH_ALEN);
1411                 memcpy(src, eth->h_source, ETH_ALEN);
1412 
1413                 padding = ((4 - subframe_len) & 0x3);
1414                 /* the last MSDU has no padding */
1415                 if (subframe_len > remaining)
1416                         return RX_DROP_UNUSABLE;
1417 
1418                 skb_pull(skb, sizeof(struct ethhdr));
1419                 /* if last subframe reuse skb */
1420                 if (remaining <= subframe_len + padding)
1421                         frame = skb;
1422                 else {
1423                         /*
1424                          * Allocate and reserve two bytes more for payload
1425                          * alignment since sizeof(struct ethhdr) is 14.
1426                          */
1427                         frame = dev_alloc_skb(
1428                                 ALIGN(local->hw.extra_tx_headroom, 4) +
1429                                 subframe_len + 2);
1430 
1431                         if (frame == NULL)
1432                                 return RX_DROP_UNUSABLE;
1433 
1434                         skb_reserve(frame,
1435                                     ALIGN(local->hw.extra_tx_headroom, 4) +
1436                                     sizeof(struct ethhdr) + 2);
1437                         memcpy(skb_put(frame, ntohs(len)), skb->data,
1438                                 ntohs(len));
1439 
1440                         eth = (struct ethhdr *) skb_pull(skb, ntohs(len) +
1441                                                         padding);
1442                         if (!eth) {
1443                                 dev_kfree_skb(frame);
1444                                 return RX_DROP_UNUSABLE;
1445                         }
1446                 }
1447 
1448                 skb_reset_network_header(frame);
1449                 frame->dev = dev;
1450                 frame->priority = skb->priority;
1451                 rx->skb = frame;
1452 
1453                 payload = frame->data;
1454                 ethertype = (payload[6] << 8) | payload[7];
1455 
1456                 if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
1457                             ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
1458                            compare_ether_addr(payload,
1459                                               bridge_tunnel_header) == 0)) {
1460                         /* remove RFC1042 or Bridge-Tunnel
1461                          * encapsulation and replace EtherType */
1462                         skb_pull(frame, 6);
1463                         memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
1464                         memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
1465                 } else {
1466                         memcpy(skb_push(frame, sizeof(__be16)),
1467                                &len, sizeof(__be16));
1468                         memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
1469                         memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
1470                 }
1471 
1472                 if (!ieee80211_frame_allowed(rx, fc)) {
1473                         if (skb == frame) /* last frame */
1474                                 return RX_DROP_UNUSABLE;
1475                         dev_kfree_skb(frame);
1476                         continue;
1477                 }
1478 
1479                 ieee80211_deliver_skb(rx);
1480         }
1481 
1482         return RX_QUEUED;
1483 }
1484 
1485 #ifdef CONFIG_MAC80211_MESH
1486 static ieee80211_rx_result
1487 ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
1488 {
1489         struct ieee80211_hdr *hdr;
1490         struct ieee80211s_hdr *mesh_hdr;
1491         unsigned int hdrlen;
1492         struct sk_buff *skb = rx->skb, *fwd_skb;
1493         struct ieee80211_local *local = rx->local;
1494         struct ieee80211_sub_if_data *sdata;
1495 
1496         hdr = (struct ieee80211_hdr *) skb->data;
1497         hdrlen = ieee80211_hdrlen(hdr->frame_control);
1498         mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
1499         sdata = IEEE80211_DEV_TO_SUB_IF(rx->dev);
1500 
1501         if (!ieee80211_is_data(hdr->frame_control))
1502                 return RX_CONTINUE;
1503 
1504         if (!mesh_hdr->ttl)
1505                 /* illegal frame */
1506                 return RX_DROP_MONITOR;
1507 
1508         if (!is_multicast_ether_addr(hdr->addr1) &&
1509                         (mesh_hdr->flags & MESH_FLAGS_AE_A5_A6)) {
1510                 struct mesh_path *mppath;
1511 
1512                 rcu_read_lock();
1513                 mppath = mpp_path_lookup(mesh_hdr->eaddr2, sdata);
1514                 if (!mppath) {
1515                         mpp_path_add(mesh_hdr->eaddr2, hdr->addr4, sdata);
1516                 } else {
1517                         spin_lock_bh(&mppath->state_lock);
1518                         if (compare_ether_addr(mppath->mpp, hdr->addr4) != 0)
1519                                 memcpy(mppath->mpp, hdr->addr4, ETH_ALEN);
1520                         spin_unlock_bh(&mppath->state_lock);
1521                 }
1522                 rcu_read_unlock();
1523         }
1524 
1525         /* Frame has reached destination.  Don't forward */
1526         if (!is_multicast_ether_addr(hdr->addr1) &&
1527                         compare_ether_addr(rx->dev->dev_addr, hdr->addr3) == 0)
1528                 return RX_CONTINUE;
1529 
1530         mesh_hdr->ttl--;
1531 
1532         if (rx->flags & IEEE80211_RX_RA_MATCH) {
1533                 if (!mesh_hdr->ttl)
1534                         IEEE80211_IFSTA_MESH_CTR_INC(&rx->sdata->u.mesh,
1535                                                      dropped_frames_ttl);
1536                 else {
1537                         struct ieee80211_hdr *fwd_hdr;
1538                         struct ieee80211_tx_info *info;
1539 
1540                         fwd_skb = skb_copy(skb, GFP_ATOMIC);
1541 
1542                         if (!fwd_skb && net_ratelimit())
1543                                 printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
1544                                                    rx->dev->name);
1545 
1546                         fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
1547                         memcpy(fwd_hdr->addr2, rx->dev->dev_addr, ETH_ALEN);
1548                         info = IEEE80211_SKB_CB(fwd_skb);
1549                         memset(info, 0, sizeof(*info));
1550                         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1551                         info->control.vif = &rx->sdata->vif;
1552                         skb_set_queue_mapping(skb,
1553                                 ieee80211_select_queue(rx->sdata, fwd_skb));
1554                         ieee80211_set_qos_hdr(local, skb);
1555                         if (is_multicast_ether_addr(fwd_hdr->addr1))
1556                                 IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1557                                                                 fwded_mcast);
1558                         else {
1559                                 int err;
1560                                 /*
1561                                  * Save TA to addr1 to send TA a path error if a
1562                                  * suitable next hop is not found
1563                                  */
1564                                 memcpy(fwd_hdr->addr1, fwd_hdr->addr2,
1565                                                 ETH_ALEN);
1566                                 err = mesh_nexthop_lookup(fwd_skb, sdata);
1567                                 /* Failed to immediately resolve next hop:
1568                                  * fwded frame was dropped or will be added
1569                                  * later to the pending skb queue.  */
1570                                 if (err)
1571                                         return RX_DROP_MONITOR;
1572 
1573                                 IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1574                                                                 fwded_unicast);
1575                         }
1576                         IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1577                                                      fwded_frames);
1578                         ieee80211_add_pending_skb(local, fwd_skb);
1579                 }
1580         }
1581 
1582         if (is_multicast_ether_addr(hdr->addr1) ||
1583             rx->dev->flags & IFF_PROMISC)
1584                 return RX_CONTINUE;
1585         else
1586                 return RX_DROP_MONITOR;
1587 }
1588 #endif
1589 
1590 static ieee80211_rx_result debug_noinline
1591 ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
1592 {
1593         struct net_device *dev = rx->dev;
1594         struct ieee80211_local *local = rx->local;
1595         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
1596         __le16 fc = hdr->frame_control;
1597         int err;
1598 
1599         if (unlikely(!ieee80211_is_data(hdr->frame_control)))
1600                 return RX_CONTINUE;
1601 
1602         if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
1603                 return RX_DROP_MONITOR;
1604 
1605         err = __ieee80211_data_to_8023(rx);
1606         if (unlikely(err))
1607                 return RX_DROP_UNUSABLE;
1608 
1609         if (!ieee80211_frame_allowed(rx, fc))
1610                 return RX_DROP_MONITOR;
1611 
1612         rx->skb->dev = dev;
1613 
1614         dev->stats.rx_packets++;
1615         dev->stats.rx_bytes += rx->skb->len;
1616 
1617         if (ieee80211_is_data(hdr->frame_control) &&
1618             !is_multicast_ether_addr(hdr->addr1) &&
1619             local->hw.conf.dynamic_ps_timeout > 0 && local->ps_sdata) {
1620                 mod_timer(&local->dynamic_ps_timer, jiffies +
1621                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
1622         }
1623 
1624         ieee80211_deliver_skb(rx);
1625 
1626         return RX_QUEUED;
1627 }
1628 
1629 static ieee80211_rx_result debug_noinline
1630 ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx)
1631 {
1632         struct ieee80211_local *local = rx->local;
1633         struct ieee80211_hw *hw = &local->hw;
1634         struct sk_buff *skb = rx->skb;
1635         struct ieee80211_bar *bar = (struct ieee80211_bar *)skb->data;
1636         struct tid_ampdu_rx *tid_agg_rx;
1637         u16 start_seq_num;
1638         u16 tid;
1639 
1640         if (likely(!ieee80211_is_ctl(bar->frame_control)))
1641                 return RX_CONTINUE;
1642 
1643         if (ieee80211_is_back_req(bar->frame_control)) {
1644                 if (!rx->sta)
1645                         return RX_CONTINUE;
1646                 tid = le16_to_cpu(bar->control) >> 12;
1647                 if (rx->sta->ampdu_mlme.tid_state_rx[tid]
1648                                         != HT_AGG_STATE_OPERATIONAL)
1649                         return RX_CONTINUE;
1650                 tid_agg_rx = rx->sta->ampdu_mlme.tid_rx[tid];
1651 
1652                 start_seq_num = le16_to_cpu(bar->start_seq_num) >> 4;
1653 
1654                 /* reset session timer */
1655                 if (tid_agg_rx->timeout)
1656                         mod_timer(&tid_agg_rx->session_timer,
1657                                   TU_TO_EXP_TIME(tid_agg_rx->timeout));
1658 
1659                 /* manage reordering buffer according to requested */
1660                 /* sequence number */
1661                 rcu_read_lock();
1662                 ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, NULL,
1663                                                  start_seq_num, 1);
1664                 rcu_read_unlock();
1665                 return RX_DROP_UNUSABLE;
1666         }
1667 
1668         return RX_CONTINUE;
1669 }
1670 
1671 static void ieee80211_process_sa_query_req(struct ieee80211_sub_if_data *sdata,
1672                                            struct ieee80211_mgmt *mgmt,
1673                                            size_t len)
1674 {
1675         struct ieee80211_local *local = sdata->local;
1676         struct sk_buff *skb;
1677         struct ieee80211_mgmt *resp;
1678 
1679         if (compare_ether_addr(mgmt->da, sdata->dev->dev_addr) != 0) {
1680                 /* Not to own unicast address */
1681                 return;
1682         }
1683 
1684         if (compare_ether_addr(mgmt->sa, sdata->u.mgd.bssid) != 0 ||
1685             compare_ether_addr(mgmt->bssid, sdata->u.mgd.bssid) != 0) {
1686                 /* Not from the current AP or not associated yet. */
1687                 return;
1688         }
1689 
1690         if (len < 24 + 1 + sizeof(resp->u.action.u.sa_query)) {
1691                 /* Too short SA Query request frame */
1692                 return;
1693         }
1694 
1695         skb = dev_alloc_skb(sizeof(*resp) + local->hw.extra_tx_headroom);
1696         if (skb == NULL)
1697                 return;
1698 
1699         skb_reserve(skb, local->hw.extra_tx_headroom);
1700         resp = (struct ieee80211_mgmt *) skb_put(skb, 24);
1701         memset(resp, 0, 24);
1702         memcpy(resp->da, mgmt->sa, ETH_ALEN);
1703         memcpy(resp->sa, sdata->dev->dev_addr, ETH_ALEN);
1704         memcpy(resp->bssid, sdata->u.mgd.bssid, ETH_ALEN);
1705         resp->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
1706                                           IEEE80211_STYPE_ACTION);
1707         skb_put(skb, 1 + sizeof(resp->u.action.u.sa_query));
1708         resp->u.action.category = WLAN_CATEGORY_SA_QUERY;
1709         resp->u.action.u.sa_query.action = WLAN_ACTION_SA_QUERY_RESPONSE;
1710         memcpy(resp->u.action.u.sa_query.trans_id,
1711                mgmt->u.action.u.sa_query.trans_id,
1712                WLAN_SA_QUERY_TR_ID_LEN);
1713 
1714         ieee80211_tx_skb(sdata, skb, 1);
1715 }
1716 
1717 static ieee80211_rx_result debug_noinline
1718 ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
1719 {
1720         struct ieee80211_local *local = rx->local;
1721         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(rx->dev);
1722         struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
1723         int len = rx->skb->len;
1724 
1725         if (!ieee80211_is_action(mgmt->frame_control))
1726                 return RX_CONTINUE;
1727 
1728         if (!rx->sta)
1729                 return RX_DROP_MONITOR;
1730 
1731         if (!(rx->flags & IEEE80211_RX_RA_MATCH))
1732                 return RX_DROP_MONITOR;
1733 
1734         if (ieee80211_drop_unencrypted(rx, mgmt->frame_control))
1735                 return RX_DROP_MONITOR;
1736 
1737         /* all categories we currently handle have action_code */
1738         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
1739                 return RX_DROP_MONITOR;
1740 
1741         switch (mgmt->u.action.category) {
1742         case WLAN_CATEGORY_BACK:
1743                 /*
1744                  * The aggregation code is not prepared to handle
1745                  * anything but STA/AP due to the BSSID handling;
1746                  * IBSS could work in the code but isn't supported
1747                  * by drivers or the standard.
1748                  */
1749                 if (sdata->vif.type != NL80211_IFTYPE_STATION &&
1750                     sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
1751                     sdata->vif.type != NL80211_IFTYPE_AP)
1752                         return RX_DROP_MONITOR;
1753 
1754                 switch (mgmt->u.action.u.addba_req.action_code) {
1755                 case WLAN_ACTION_ADDBA_REQ:
1756                         if (len < (IEEE80211_MIN_ACTION_SIZE +
1757                                    sizeof(mgmt->u.action.u.addba_req)))
1758                                 return RX_DROP_MONITOR;
1759                         ieee80211_process_addba_request(local, rx->sta, mgmt, len);
1760                         break;
1761                 case WLAN_ACTION_ADDBA_RESP:
1762                         if (len < (IEEE80211_MIN_ACTION_SIZE +
1763                                    sizeof(mgmt->u.action.u.addba_resp)))
1764                                 return RX_DROP_MONITOR;
1765                         ieee80211_process_addba_resp(local, rx->sta, mgmt, len);
1766                         break;
1767                 case WLAN_ACTION_DELBA:
1768                         if (len < (IEEE80211_MIN_ACTION_SIZE +
1769                                    sizeof(mgmt->u.action.u.delba)))
1770                                 return RX_DROP_MONITOR;
1771                         ieee80211_process_delba(sdata, rx->sta, mgmt, len);
1772                         break;
1773                 }
1774                 break;
1775         case WLAN_CATEGORY_SPECTRUM_MGMT:
1776                 if (local->hw.conf.channel->band != IEEE80211_BAND_5GHZ)
1777                         return RX_DROP_MONITOR;
1778 
1779                 if (sdata->vif.type != NL80211_IFTYPE_STATION)
1780                         return RX_DROP_MONITOR;
1781 
1782                 switch (mgmt->u.action.u.measurement.action_code) {
1783                 case WLAN_ACTION_SPCT_MSR_REQ:
1784                         if (len < (IEEE80211_MIN_ACTION_SIZE +
1785                                    sizeof(mgmt->u.action.u.measurement)))
1786                                 return RX_DROP_MONITOR;
1787                         ieee80211_process_measurement_req(sdata, mgmt, len);
1788                         break;
1789                 case WLAN_ACTION_SPCT_CHL_SWITCH:
1790                         if (len < (IEEE80211_MIN_ACTION_SIZE +
1791                                    sizeof(mgmt->u.action.u.chan_switch)))
1792                                 return RX_DROP_MONITOR;
1793 
1794                         if (sdata->vif.type != NL80211_IFTYPE_STATION)
1795                                 return RX_DROP_MONITOR;
1796 
1797                         if (memcmp(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN))
1798                                 return RX_DROP_MONITOR;
1799 
1800                         return ieee80211_sta_rx_mgmt(sdata, rx->skb);
1801                 }
1802                 break;
1803         case WLAN_CATEGORY_SA_QUERY:
1804                 if (len < (IEEE80211_MIN_ACTION_SIZE +
1805                            sizeof(mgmt->u.action.u.sa_query)))
1806                         return RX_DROP_MONITOR;
1807                 switch (mgmt->u.action.u.sa_query.action) {
1808                 case WLAN_ACTION_SA_QUERY_REQUEST:
1809                         if (sdata->vif.type != NL80211_IFTYPE_STATION)
1810                                 return RX_DROP_MONITOR;
1811                         ieee80211_process_sa_query_req(sdata, mgmt, len);
1812                         break;
1813                 case WLAN_ACTION_SA_QUERY_RESPONSE:
1814                         /*
1815                          * SA Query response is currently only used in AP mode
1816                          * and it is processed in user space.
1817                          */
1818                         return RX_CONTINUE;
1819                 }
1820                 break;
1821         case WLAN_CATEGORY_MESH_PLINK:
1822         case WLAN_CATEGORY_MESH_PATH_SEL:
1823                 if (ieee80211_vif_is_mesh(&sdata->vif))
1824                         return ieee80211_mesh_rx_mgmt(sdata, rx->skb);
1825                 break;
1826         default:
1827                 /* do not process rejected action frames */
1828                 if (mgmt->u.action.category & 0x80)
1829                         return RX_DROP_MONITOR;
1830 
1831                 return RX_CONTINUE;
1832         }
1833 
1834         rx->sta->rx_packets++;
1835         dev_kfree_skb(rx->skb);
1836         return RX_QUEUED;
1837 }
1838 
1839 static ieee80211_rx_result debug_noinline
1840 ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
1841 {
1842         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(rx->dev);
1843         struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
1844 
1845         if (!(rx->flags & IEEE80211_RX_RA_MATCH))
1846                 return RX_DROP_MONITOR;
1847 
1848         if (ieee80211_drop_unencrypted(rx, mgmt->frame_control))
1849                 return RX_DROP_MONITOR;
1850 
1851         if (ieee80211_vif_is_mesh(&sdata->vif))
1852                 return ieee80211_mesh_rx_mgmt(sdata, rx->skb);
1853 
1854         if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
1855                 return ieee80211_ibss_rx_mgmt(sdata, rx->skb);
1856 
1857         if (sdata->vif.type == NL80211_IFTYPE_STATION)
1858                 return ieee80211_sta_rx_mgmt(sdata, rx->skb);
1859 
1860         return RX_DROP_MONITOR;
1861 }
1862 
1863 static void ieee80211_rx_michael_mic_report(struct ieee80211_hdr *hdr,
1864                                             struct ieee80211_rx_data *rx)
1865 {
1866         int keyidx;
1867         unsigned int hdrlen;
1868 
1869         hdrlen = ieee80211_hdrlen(hdr->frame_control);
1870         if (rx->skb->len >= hdrlen + 4)
1871                 keyidx = rx->skb->data[hdrlen + 3] >> 6;
1872         else
1873                 keyidx = -1;
1874 
1875         if (!rx->sta) {
1876                 /*
1877                  * Some hardware seem to generate incorrect Michael MIC
1878                  * reports; ignore them to avoid triggering countermeasures.
1879                  */
1880                 goto ignore;
1881         }
1882 
1883         if (!ieee80211_has_protected(hdr->frame_control))
1884                 goto ignore;
1885 
1886         if (rx->sdata->vif.type == NL80211_IFTYPE_AP && keyidx) {
1887                 /*
1888                  * APs with pairwise keys should never receive Michael MIC
1889                  * errors for non-zero keyidx because these are reserved for
1890                  * group keys and only the AP is sending real multicast
1891                  * frames in the BSS.
1892                  */
1893                 goto ignore;
1894         }
1895 
1896         if (!ieee80211_is_data(hdr->frame_control) &&
1897             !ieee80211_is_auth(hdr->frame_control))
1898                 goto ignore;
1899 
1900         mac80211_ev_michael_mic_failure(rx->sdata, keyidx, hdr, NULL,
1901                                         GFP_ATOMIC);
1902  ignore:
1903         dev_kfree_skb(rx->skb);
1904         rx->skb = NULL;
1905 }
1906 
1907 /* TODO: use IEEE80211_RX_FRAGMENTED */
1908 static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx)
1909 {
1910         struct ieee80211_sub_if_data *sdata;
1911         struct ieee80211_local *local = rx->local;
1912         struct ieee80211_rtap_hdr {
1913                 struct ieee80211_radiotap_header hdr;
1914                 u8 flags;
1915                 u8 rate;
1916                 __le16 chan_freq;
1917                 __le16 chan_flags;
1918         } __attribute__ ((packed)) *rthdr;
1919         struct sk_buff *skb = rx->skb, *skb2;
1920         struct net_device *prev_dev = NULL;
1921         struct ieee80211_rx_status *status = rx->status;
1922 
1923         if (rx->flags & IEEE80211_RX_CMNTR_REPORTED)
1924                 goto out_free_skb;
1925 
1926         if (skb_headroom(skb) < sizeof(*rthdr) &&
1927             pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
1928                 goto out_free_skb;
1929 
1930         rthdr = (void *)skb_push(skb, sizeof(*rthdr));
1931         memset(rthdr, 0, sizeof(*rthdr));
1932         rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
1933         rthdr->hdr.it_present =
1934                 cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
1935                             (1 << IEEE80211_RADIOTAP_RATE) |
1936                             (1 << IEEE80211_RADIOTAP_CHANNEL));
1937 
1938         rthdr->rate = rx->rate->bitrate / 5;
1939         rthdr->chan_freq = cpu_to_le16(status->freq);
1940 
1941         if (status->band == IEEE80211_BAND_5GHZ)
1942                 rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_OFDM |
1943                                                 IEEE80211_CHAN_5GHZ);
1944         else
1945                 rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_DYN |
1946                                                 IEEE80211_CHAN_2GHZ);
1947 
1948         skb_set_mac_header(skb, 0);
1949         skb->ip_summed = CHECKSUM_UNNECESSARY;
1950         skb->pkt_type = PACKET_OTHERHOST;
1951         skb->protocol = htons(ETH_P_802_2);
1952 
1953         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
1954                 if (!netif_running(sdata->dev))
1955                         continue;
1956 
1957                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR ||
1958                     !(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
1959                         continue;
1960 
1961                 if (prev_dev) {
1962                         skb2 = skb_clone(skb, GFP_ATOMIC);
1963                         if (skb2) {
1964                                 skb2->dev = prev_dev;
1965                                 netif_rx(skb2);
1966                         }
1967                 }
1968 
1969                 prev_dev = sdata->dev;
1970                 sdata->dev->stats.rx_packets++;
1971                 sdata->dev->stats.rx_bytes += skb->len;
1972         }
1973 
1974         if (prev_dev) {
1975                 skb->dev = prev_dev;
1976                 netif_rx(skb);
1977                 skb = NULL;
1978         } else
1979                 goto out_free_skb;
1980 
1981         rx->flags |= IEEE80211_RX_CMNTR_REPORTED;
1982         return;
1983 
1984  out_free_skb:
1985         dev_kfree_skb(skb);
1986 }
1987 
1988 
1989 static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata,
1990                                          struct ieee80211_rx_data *rx,
1991                                          struct sk_buff *skb)
1992 {
1993         ieee80211_rx_result res = RX_DROP_MONITOR;
1994 
1995         rx->skb = skb;
1996         rx->sdata = sdata;
1997         rx->dev = sdata->dev;
1998 
1999 #define CALL_RXH(rxh)                   \
2000         do {                            \
2001                 res = rxh(rx);          \
2002                 if (res != RX_CONTINUE) \
2003                         goto rxh_done;  \
2004         } while (0);
2005 
2006         CALL_RXH(ieee80211_rx_h_passive_scan)
2007         CALL_RXH(ieee80211_rx_h_check)
2008         CALL_RXH(ieee80211_rx_h_decrypt)
2009         CALL_RXH(ieee80211_rx_h_check_more_data)
2010         CALL_RXH(ieee80211_rx_h_sta_process)
2011         CALL_RXH(ieee80211_rx_h_defragment)
2012         CALL_RXH(ieee80211_rx_h_ps_poll)
2013         CALL_RXH(ieee80211_rx_h_michael_mic_verify)
2014         /* must be after MMIC verify so header is counted in MPDU mic */
2015         CALL_RXH(ieee80211_rx_h_remove_qos_control)
2016         CALL_RXH(ieee80211_rx_h_amsdu)
2017 #ifdef CONFIG_MAC80211_MESH
2018         if (ieee80211_vif_is_mesh(&sdata->vif))
2019                 CALL_RXH(ieee80211_rx_h_mesh_fwding);
2020 #endif
2021         CALL_RXH(ieee80211_rx_h_data)
2022         CALL_RXH(ieee80211_rx_h_ctrl)
2023         CALL_RXH(ieee80211_rx_h_action)
2024         CALL_RXH(ieee80211_rx_h_mgmt)
2025 
2026 #undef CALL_RXH
2027 
2028  rxh_done:
2029         switch (res) {
2030         case RX_DROP_MONITOR:
2031                 I802_DEBUG_INC(sdata->local->rx_handlers_drop);
2032                 if (rx->sta)
2033                         rx->sta->rx_dropped++;
2034                 /* fall through */
2035         case RX_CONTINUE:
2036                 ieee80211_rx_cooked_monitor(rx);
2037                 break;
2038         case RX_DROP_UNUSABLE:
2039                 I802_DEBUG_INC(sdata->local->rx_handlers_drop);
2040                 if (rx->sta)
2041                         rx->sta->rx_dropped++;
2042                 dev_kfree_skb(rx->skb);
2043                 break;
2044         case RX_QUEUED:
2045                 I802_DEBUG_INC(sdata->local->rx_handlers_queued);
2046                 break;
2047         }
2048 }
2049 
2050 /* main receive path */
2051 
2052 static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
2053                                 struct ieee80211_rx_data *rx,
2054                                 struct ieee80211_hdr *hdr)
2055 {
2056         u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len, sdata->vif.type);
2057         int multicast = is_multicast_ether_addr(hdr->addr1);
2058 
2059         switch (sdata->vif.type) {
2060         case NL80211_IFTYPE_STATION:
2061                 if (!bssid)
2062                         return 0;
2063                 if (!multicast &&
2064                     compare_ether_addr(sdata->dev->dev_addr, hdr->addr1) != 0) {
2065                         if (!(sdata->dev->flags & IFF_PROMISC))
2066                                 return 0;
2067                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
2068                 }
2069                 break;
2070         case NL80211_IFTYPE_ADHOC:
2071                 if (!bssid)
2072                         return 0;
2073                 if (ieee80211_is_beacon(hdr->frame_control)) {
2074                         return 1;
2075                 }
2076                 else if (!ieee80211_bssid_match(bssid, sdata->u.ibss.bssid)) {
2077                         if (!(rx->flags & IEEE80211_RX_IN_SCAN))
2078                                 return 0;
2079                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
2080                 } else if (!multicast &&
2081                            compare_ether_addr(sdata->dev->dev_addr,
2082                                               hdr->addr1) != 0) {
2083                         if (!(sdata->dev->flags & IFF_PROMISC))
2084                                 return 0;
2085                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
2086                 } else if (!rx->sta) {
2087                         int rate_idx;
2088                         if (rx->status->flag & RX_FLAG_HT)
2089                                 rate_idx = 0; /* TODO: HT rates */
2090                         else
2091                                 rate_idx = rx->status->rate_idx;
2092                         rx->sta = ieee80211_ibss_add_sta(sdata, bssid, hdr->addr2,
2093                                 BIT(rate_idx));
2094                 }
2095                 break;
2096         case NL80211_IFTYPE_MESH_POINT:
2097                 if (!multicast &&
2098                     compare_ether_addr(sdata->dev->dev_addr,
2099                                        hdr->addr1) != 0) {
2100                         if (!(sdata->dev->flags & IFF_PROMISC))
2101                                 return 0;
2102 
2103                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
2104                 }
2105                 break;
2106         case NL80211_IFTYPE_AP_VLAN:
2107         case NL80211_IFTYPE_AP:
2108                 if (!bssid) {
2109                         if (compare_ether_addr(sdata->dev->dev_addr,
2110                                                hdr->addr1))
2111                                 return 0;
2112                 } else if (!ieee80211_bssid_match(bssid,
2113                                         sdata->dev->dev_addr)) {
2114                         if (!(rx->flags & IEEE80211_RX_IN_SCAN))
2115                                 return 0;
2116                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
2117                 }
2118                 break;
2119         case NL80211_IFTYPE_WDS:
2120                 if (bssid || !ieee80211_is_data(hdr->frame_control))
2121                         return 0;
2122                 if (compare_ether_addr(sdata->u.wds.remote_addr, hdr->addr2))
2123                         return 0;
2124                 break;
2125         case NL80211_IFTYPE_MONITOR:
2126                 /* take everything */
2127                 break;
2128         case NL80211_IFTYPE_UNSPECIFIED:
2129         case __NL80211_IFTYPE_AFTER_LAST:
2130                 /* should never get here */
2131                 WARN_ON(1);
2132                 break;
2133         }
2134 
2135         return 1;
2136 }
2137 
2138 /*
2139  * This is the actual Rx frames handler. as it blongs to Rx path it must
2140  * be called with rcu_read_lock protection.
2141  */
2142 static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
2143                                          struct sk_buff *skb,
2144                                          struct ieee80211_rate *rate)
2145 {
2146         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2147         struct ieee80211_local *local = hw_to_local(hw);
2148         struct ieee80211_sub_if_data *sdata;
2149         struct ieee80211_hdr *hdr;
2150         struct ieee80211_rx_data rx;
2151         int prepares;
2152         struct ieee80211_sub_if_data *prev = NULL;
2153         struct sk_buff *skb_new;
2154 
2155         hdr = (struct ieee80211_hdr *)skb->data;
2156         memset(&rx, 0, sizeof(rx));
2157         rx.skb = skb;
2158         rx.local = local;
2159 
2160         rx.status = status;
2161         rx.rate = rate;
2162 
2163         if (ieee80211_is_data(hdr->frame_control) || ieee80211_is_mgmt(hdr->frame_control))
2164                 local->dot11ReceivedFragmentCount++;
2165 
2166         rx.sta = sta_info_get(local, hdr->addr2);
2167         if (rx.sta) {
2168                 rx.sdata = rx.sta->sdata;
2169                 rx.dev = rx.sta->sdata->dev;
2170         }
2171 
2172         if ((status->flag & RX_FLAG_MMIC_ERROR)) {
2173                 ieee80211_rx_michael_mic_report(hdr, &rx);
2174                 return;
2175         }
2176 
2177         if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
2178                      test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
2179                 rx.flags |= IEEE80211_RX_IN_SCAN;
2180 
2181         ieee80211_parse_qos(&rx);
2182         ieee80211_verify_alignment(&rx);
2183 
2184         skb = rx.skb;
2185 
2186         if (rx.sdata && ieee80211_is_data(hdr->frame_control)) {
2187                 rx.flags |= IEEE80211_RX_RA_MATCH;
2188                 prepares = prepare_for_handlers(rx.sdata, &rx, hdr);
2189                 if (prepares)
2190                         prev = rx.sdata;
2191         } else list_for_each_entry_rcu(sdata, &local->interfaces, list) {
2192                 if (!netif_running(sdata->dev))
2193                         continue;
2194 
2195                 if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
2196                     sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
2197                         continue;
2198 
2199                 rx.flags |= IEEE80211_RX_RA_MATCH;
2200                 prepares = prepare_for_handlers(sdata, &rx, hdr);
2201 
2202                 if (!prepares)
2203                         continue;
2204 
2205                 /*
2206                  * frame is destined for this interface, but if it's not
2207                  * also for the previous one we handle that after the
2208                  * loop to avoid copying the SKB once too much
2209                  */
2210 
2211                 if (!prev) {
2212                         prev = sdata;
2213                         continue;
2214                 }
2215 
2216                 /*
2217                  * frame was destined for the previous interface
2218                  * so invoke RX handlers for it
2219                  */
2220 
2221                 skb_new = skb_copy(skb, GFP_ATOMIC);
2222                 if (!skb_new) {
2223                         if (net_ratelimit())
2224                                 printk(KERN_DEBUG "%s: failed to copy "
2225                                        "multicast frame for %s\n",
2226                                        wiphy_name(local->hw.wiphy),
2227                                        prev->dev->name);
2228                         continue;
2229                 }
2230                 ieee80211_invoke_rx_handlers(prev, &rx, skb_new);
2231                 prev = sdata;
2232         }
2233         if (prev)
2234                 ieee80211_invoke_rx_handlers(prev, &rx, skb);
2235         else
2236                 dev_kfree_skb(skb);
2237 }
2238 
2239 #define SEQ_MODULO 0x1000
2240 #define SEQ_MASK   0xfff
2241 
2242 static inline int seq_less(u16 sq1, u16 sq2)
2243 {
2244         return ((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1);
2245 }
2246 
2247 static inline u16 seq_inc(u16 sq)
2248 {
2249         return (sq + 1) & SEQ_MASK;
2250 }
2251 
2252 static inline u16 seq_sub(u16 sq1, u16 sq2)
2253 {
2254         return (sq1 - sq2) & SEQ_MASK;
2255 }
2256 
2257 
2258 static void ieee80211_release_reorder_frame(struct ieee80211_hw *hw,
2259                                             struct tid_ampdu_rx *tid_agg_rx,
2260                                             int index)
2261 {
2262         struct ieee80211_supported_band *sband;
2263         struct ieee80211_rate *rate;
2264         struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
2265         struct ieee80211_rx_status *status;
2266 
2267         if (!skb)
2268                 goto no_frame;
2269 
2270         status = IEEE80211_SKB_RXCB(skb);
2271 
2272         /* release the reordered frames to stack */
2273         sband = hw->wiphy->bands[status->band];
2274         if (status->flag & RX_FLAG_HT)
2275                 rate = sband->bitrates; /* TODO: HT rates */
2276         else
2277                 rate = &sband->bitrates[status->rate_idx];
2278         __ieee80211_rx_handle_packet(hw, skb, rate);
2279         tid_agg_rx->stored_mpdu_num--;
2280         tid_agg_rx->reorder_buf[index] = NULL;
2281 
2282 no_frame:
2283         tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
2284 }
2285 
2286 
2287 /*
2288  * Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If
2289  * the skb was added to the buffer longer than this time ago, the earlier
2290  * frames that have not yet been received are assumed to be lost and the skb
2291  * can be released for processing. This may also release other skb's from the
2292  * reorder buffer if there are no additional gaps between the frames.
2293  */
2294 #define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
2295 
2296 /*
2297  * As it function blongs to Rx path it must be called with
2298  * the proper rcu_read_lock protection for its flow.
2299  */
2300 static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
2301                                            struct tid_ampdu_rx *tid_agg_rx,
2302                                            struct sk_buff *skb,
2303                                            u16 mpdu_seq_num,
2304                                            int bar_req)
2305 {
2306         u16 head_seq_num, buf_size;
2307         int index;
2308 
2309         buf_size = tid_agg_rx->buf_size;
2310         head_seq_num = tid_agg_rx->head_seq_num;
2311 
2312         /* frame with out of date sequence number */
2313         if (seq_less(mpdu_seq_num, head_seq_num)) {
2314                 dev_kfree_skb(skb);
2315                 return 1;
2316         }
2317 
2318         /* if frame sequence number exceeds our buffering window size or
2319          * block Ack Request arrived - release stored frames */
2320         if ((!seq_less(mpdu_seq_num, head_seq_num + buf_size)) || (bar_req)) {
2321                 /* new head to the ordering buffer */
2322                 if (bar_req)
2323                         head_seq_num = mpdu_seq_num;
2324                 else
2325                         head_seq_num =
2326                                 seq_inc(seq_sub(mpdu_seq_num, buf_size));
2327                 /* release stored frames up to new head to stack */
2328                 while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
2329                         index = seq_sub(tid_agg_rx->head_seq_num,
2330                                 tid_agg_rx->ssn)
2331                                 % tid_agg_rx->buf_size;
2332                         ieee80211_release_reorder_frame(hw, tid_agg_rx,
2333                                                         index);
2334                 }
2335                 if (bar_req)
2336                         return 1;
2337         }
2338 
2339         /* now the new frame is always in the range of the reordering */
2340         /* buffer window */
2341         index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn)
2342                                 % tid_agg_rx->buf_size;
2343         /* check if we already stored this frame */
2344         if (tid_agg_rx->reorder_buf[index]) {
2345                 dev_kfree_skb(skb);
2346                 return 1;
2347         }
2348 
2349         /* if arrived mpdu is in the right order and nothing else stored */
2350         /* release it immediately */
2351         if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
2352                         tid_agg_rx->stored_mpdu_num == 0) {
2353                 tid_agg_rx->head_seq_num =
2354                         seq_inc(tid_agg_rx->head_seq_num);
2355                 return 0;
2356         }
2357 
2358         /* put the frame in the reordering buffer */
2359         tid_agg_rx->reorder_buf[index] = skb;
2360         tid_agg_rx->reorder_time[index] = jiffies;
2361         tid_agg_rx->stored_mpdu_num++;
2362         /* release the buffer until next missing frame */
2363         index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn)
2364                                                 % tid_agg_rx->buf_size;
2365         if (!tid_agg_rx->reorder_buf[index] &&
2366             tid_agg_rx->stored_mpdu_num) {
2367                 /*
2368                  * No buffers ready to be released, but check whether any
2369                  * frames in the reorder buffer have timed out.
2370                  */
2371                 int j;
2372                 int skipped = 1;
2373                 for (j = (index + 1) % tid_agg_rx->buf_size; j != index;
2374                      j = (j + 1) % tid_agg_rx->buf_size) {
2375                         if (tid_agg_rx->reorder_buf[j] == NULL) {
2376                                 skipped++;
2377                                 continue;
2378                         }
2379                         if (!time_after(jiffies, tid_agg_rx->reorder_time[j] +
2380                                         HZ / 10))
2381                                 break;
2382 
2383 #ifdef CONFIG_MAC80211_HT_DEBUG
2384                         if (net_ratelimit())
2385                                 printk(KERN_DEBUG "%s: release an RX reorder "
2386                                        "frame due to timeout on earlier "
2387                                        "frames\n",
2388                                        wiphy_name(hw->wiphy));
2389 #endif
2390                         ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
2391 
2392                         /*
2393                          * Increment the head seq# also for the skipped slots.
2394                          */
2395                         tid_agg_rx->head_seq_num =
2396                                 (tid_agg_rx->head_seq_num + skipped) &
2397                                 SEQ_MASK;
2398                         skipped = 0;
2399                 }
2400         } else while (tid_agg_rx->reorder_buf[index]) {
2401                 ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
2402                 index = seq_sub(tid_agg_rx->head_seq_num,
2403                         tid_agg_rx->ssn) % tid_agg_rx->buf_size;
2404         }
2405         return 1;
2406 }
2407 
2408 static u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local,
2409                                      struct sk_buff *skb)
2410 {
2411         struct ieee80211_hw *hw = &local->hw;
2412         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
2413         struct sta_info *sta;
2414         struct tid_ampdu_rx *tid_agg_rx;
2415         u16 sc;
2416         u16 mpdu_seq_num;
2417         u8 ret = 0;
2418         int tid;
2419 
2420         sta = sta_info_get(local, hdr->addr2);
2421         if (!sta)
2422                 return ret;
2423 
2424         /* filter the QoS data rx stream according to
2425          * STA/TID and check if this STA/TID is on aggregation */
2426         if (!ieee80211_is_data_qos(hdr->frame_control))
2427                 goto end_reorder;
2428 
2429         tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
2430 
2431         if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL)
2432                 goto end_reorder;
2433 
2434         tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];
2435 
2436         /* qos null data frames are excluded */
2437         if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
2438                 goto end_reorder;
2439 
2440         /* new un-ordered ampdu frame - process it */
2441 
2442         /* reset session timer */
2443         if (tid_agg_rx->timeout)
2444                 mod_timer(&tid_agg_rx->session_timer,
2445                           TU_TO_EXP_TIME(tid_agg_rx->timeout));
2446 
2447         /* if this mpdu is fragmented - terminate rx aggregation session */
2448         sc = le16_to_cpu(hdr->seq_ctrl);
2449         if (sc & IEEE80211_SCTL_FRAG) {
2450                 ieee80211_sta_stop_rx_ba_session(sta->sdata, sta->sta.addr,
2451                         tid, 0, WLAN_REASON_QSTA_REQUIRE_SETUP);
2452                 ret = 1;
2453                 goto end_reorder;
2454         }
2455 
2456         /* according to mpdu sequence number deal with reordering buffer */
2457         mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
2458         ret = ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb,
2459                                                 mpdu_seq_num, 0);
2460  end_reorder:
2461         return ret;
2462 }
2463 
2464 /*
2465  * This is the receive path handler. It is called by a low level driver when an
2466  * 802.11 MPDU is received from the hardware.
2467  */
2468 void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
2469 {
2470         struct ieee80211_local *local = hw_to_local(hw);
2471         struct ieee80211_rate *rate = NULL;
2472         struct ieee80211_supported_band *sband;
2473         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2474 
2475         WARN_ON_ONCE(softirq_count() == 0);
2476 
2477         if (WARN_ON(status->band < 0 ||
2478                     status->band >= IEEE80211_NUM_BANDS))
2479                 goto drop;
2480 
2481         sband = local->hw.wiphy->bands[status->band];
2482         if (WARN_ON(!sband))
2483                 goto drop;
2484 
2485         /*
2486          * If we're suspending, it is possible although not too likely
2487          * that we'd be receiving frames after having already partially
2488          * quiesced the stack. We can't process such frames then since
2489          * that might, for example, cause stations to be added or other
2490          * driver callbacks be invoked.
2491          */
2492         if (unlikely(local->quiescing || local->suspended))
2493                 goto drop;
2494 
2495         /*
2496          * The same happens when we're not even started,
2497          * but that's worth a warning.
2498          */
2499         if (WARN_ON(!local->started))
2500                 goto drop;
2501 
2502         if (status->flag & RX_FLAG_HT) {
2503                 /* rate_idx is MCS index */
2504                 if (WARN_ON(status->rate_idx < 0 ||
2505                             status->rate_idx >= 76))
2506                         goto drop;
2507                 /* HT rates are not in the table - use the highest legacy rate
2508                  * for now since other parts of mac80211 may not yet be fully
2509                  * MCS aware. */
2510                 rate = &sband->bitrates[sband->n_bitrates - 1];
2511         } else {
2512                 if (WARN_ON(status->rate_idx < 0 ||
2513                             status->rate_idx >= sband->n_bitrates))
2514                         goto drop;
2515                 rate = &sband->bitrates[status->rate_idx];
2516         }
2517 
2518         /*
2519          * key references and virtual interfaces are protected using RCU
2520          * and this requires that we are in a read-side RCU section during
2521          * receive processing
2522          */
2523         rcu_read_lock();
2524 
2525         /*
2526          * Frames with failed FCS/PLCP checksum are not returned,
2527          * all other frames are returned without radiotap header
2528          * if it was previously present.
2529          * Also, frames with less than 16 bytes are dropped.
2530          */
2531         skb = ieee80211_rx_monitor(local, skb, rate);
2532         if (!skb) {
2533                 rcu_read_unlock();
2534                 return;
2535         }
2536 
2537         /*
2538          * In theory, the block ack reordering should happen after duplicate
2539          * removal (ieee80211_rx_h_check(), which is an RX handler). As such,
2540          * the call to ieee80211_rx_reorder_ampdu() should really be moved to
2541          * happen as a new RX handler between ieee80211_rx_h_check and
2542          * ieee80211_rx_h_decrypt. This cleanup may eventually happen, but for
2543          * the time being, the call can be here since RX reorder buf processing
2544          * will implicitly skip duplicates. We could, in theory at least,
2545          * process frames that ieee80211_rx_h_passive_scan would drop (e.g.,
2546          * frames from other than operational channel), but that should not
2547          * happen in normal networks.
2548          */
2549         if (!ieee80211_rx_reorder_ampdu(local, skb))
2550                 __ieee80211_rx_handle_packet(hw, skb, rate);
2551 
2552         rcu_read_unlock();
2553 
2554         return;
2555  drop:
2556         kfree_skb(skb);
2557 }
2558 EXPORT_SYMBOL(ieee80211_rx);
2559 
2560 /* This is a version of the rx handler that can be called from hard irq
2561  * context. Post the skb on the queue and schedule the tasklet */
2562 void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb)
2563 {
2564         struct ieee80211_local *local = hw_to_local(hw);
2565 
2566         BUILD_BUG_ON(sizeof(struct ieee80211_rx_status) > sizeof(skb->cb));
2567 
2568         skb->pkt_type = IEEE80211_RX_MSG;
2569         skb_queue_tail(&local->skb_queue, skb);
2570         tasklet_schedule(&local->tasklet);
2571 }
2572 EXPORT_SYMBOL(ieee80211_rx_irqsafe);
2573 

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