xref: /openbmc/linux/net/mac80211/rx.c (revision e4c0d0e2)
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 2007-2010	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/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/skbuff.h>
16 #include <linux/netdevice.h>
17 #include <linux/etherdevice.h>
18 #include <linux/rcupdate.h>
19 #include <net/mac80211.h>
20 #include <net/ieee80211_radiotap.h>
21 
22 #include "ieee80211_i.h"
23 #include "driver-ops.h"
24 #include "led.h"
25 #include "mesh.h"
26 #include "wep.h"
27 #include "wpa.h"
28 #include "tkip.h"
29 #include "wme.h"
30 
31 /*
32  * monitor mode reception
33  *
34  * This function cleans up the SKB, i.e. it removes all the stuff
35  * only useful for monitoring.
36  */
37 static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
38 					   struct sk_buff *skb)
39 {
40 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
41 		if (likely(skb->len > FCS_LEN))
42 			__pskb_trim(skb, skb->len - FCS_LEN);
43 		else {
44 			/* driver bug */
45 			WARN_ON(1);
46 			dev_kfree_skb(skb);
47 			skb = NULL;
48 		}
49 	}
50 
51 	return skb;
52 }
53 
54 static inline int should_drop_frame(struct sk_buff *skb,
55 				    int present_fcs_len)
56 {
57 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
58 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
59 
60 	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
61 		return 1;
62 	if (unlikely(skb->len < 16 + present_fcs_len))
63 		return 1;
64 	if (ieee80211_is_ctl(hdr->frame_control) &&
65 	    !ieee80211_is_pspoll(hdr->frame_control) &&
66 	    !ieee80211_is_back_req(hdr->frame_control))
67 		return 1;
68 	return 0;
69 }
70 
71 static int
72 ieee80211_rx_radiotap_len(struct ieee80211_local *local,
73 			  struct ieee80211_rx_status *status)
74 {
75 	int len;
76 
77 	/* always present fields */
78 	len = sizeof(struct ieee80211_radiotap_header) + 9;
79 
80 	if (status->flag & RX_FLAG_MACTIME_MPDU)
81 		len += 8;
82 	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
83 		len += 1;
84 
85 	if (len & 1) /* padding for RX_FLAGS if necessary */
86 		len++;
87 
88 	if (status->flag & RX_FLAG_HT) /* HT info */
89 		len += 3;
90 
91 	return len;
92 }
93 
94 /*
95  * ieee80211_add_rx_radiotap_header - add radiotap header
96  *
97  * add a radiotap header containing all the fields which the hardware provided.
98  */
99 static void
100 ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
101 				 struct sk_buff *skb,
102 				 struct ieee80211_rate *rate,
103 				 int rtap_len)
104 {
105 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
106 	struct ieee80211_radiotap_header *rthdr;
107 	unsigned char *pos;
108 	u16 rx_flags = 0;
109 
110 	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
111 	memset(rthdr, 0, rtap_len);
112 
113 	/* radiotap header, set always present flags */
114 	rthdr->it_present =
115 		cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
116 			    (1 << IEEE80211_RADIOTAP_CHANNEL) |
117 			    (1 << IEEE80211_RADIOTAP_ANTENNA) |
118 			    (1 << IEEE80211_RADIOTAP_RX_FLAGS));
119 	rthdr->it_len = cpu_to_le16(rtap_len);
120 
121 	pos = (unsigned char *)(rthdr+1);
122 
123 	/* the order of the following fields is important */
124 
125 	/* IEEE80211_RADIOTAP_TSFT */
126 	if (status->flag & RX_FLAG_MACTIME_MPDU) {
127 		put_unaligned_le64(status->mactime, pos);
128 		rthdr->it_present |=
129 			cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
130 		pos += 8;
131 	}
132 
133 	/* IEEE80211_RADIOTAP_FLAGS */
134 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
135 		*pos |= IEEE80211_RADIOTAP_F_FCS;
136 	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
137 		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
138 	if (status->flag & RX_FLAG_SHORTPRE)
139 		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
140 	pos++;
141 
142 	/* IEEE80211_RADIOTAP_RATE */
143 	if (status->flag & RX_FLAG_HT) {
144 		/*
145 		 * MCS information is a separate field in radiotap,
146 		 * added below. The byte here is needed as padding
147 		 * for the channel though, so initialise it to 0.
148 		 */
149 		*pos = 0;
150 	} else {
151 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
152 		*pos = rate->bitrate / 5;
153 	}
154 	pos++;
155 
156 	/* IEEE80211_RADIOTAP_CHANNEL */
157 	put_unaligned_le16(status->freq, pos);
158 	pos += 2;
159 	if (status->band == IEEE80211_BAND_5GHZ)
160 		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
161 				   pos);
162 	else if (status->flag & RX_FLAG_HT)
163 		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
164 				   pos);
165 	else if (rate->flags & IEEE80211_RATE_ERP_G)
166 		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
167 				   pos);
168 	else
169 		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
170 				   pos);
171 	pos += 2;
172 
173 	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
174 	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
175 		*pos = status->signal;
176 		rthdr->it_present |=
177 			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
178 		pos++;
179 	}
180 
181 	/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
182 
183 	/* IEEE80211_RADIOTAP_ANTENNA */
184 	*pos = status->antenna;
185 	pos++;
186 
187 	/* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
188 
189 	/* IEEE80211_RADIOTAP_RX_FLAGS */
190 	/* ensure 2 byte alignment for the 2 byte field as required */
191 	if ((pos - (u8 *)rthdr) & 1)
192 		pos++;
193 	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
194 		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
195 	put_unaligned_le16(rx_flags, pos);
196 	pos += 2;
197 
198 	if (status->flag & RX_FLAG_HT) {
199 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
200 		*pos++ = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
201 			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
202 			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
203 		*pos = 0;
204 		if (status->flag & RX_FLAG_SHORT_GI)
205 			*pos |= IEEE80211_RADIOTAP_MCS_SGI;
206 		if (status->flag & RX_FLAG_40MHZ)
207 			*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
208 		pos++;
209 		*pos++ = status->rate_idx;
210 	}
211 }
212 
213 /*
214  * This function copies a received frame to all monitor interfaces and
215  * returns a cleaned-up SKB that no longer includes the FCS nor the
216  * radiotap header the driver might have added.
217  */
218 static struct sk_buff *
219 ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
220 		     struct ieee80211_rate *rate)
221 {
222 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
223 	struct ieee80211_sub_if_data *sdata;
224 	int needed_headroom = 0;
225 	struct sk_buff *skb, *skb2;
226 	struct net_device *prev_dev = NULL;
227 	int present_fcs_len = 0;
228 
229 	/*
230 	 * First, we may need to make a copy of the skb because
231 	 *  (1) we need to modify it for radiotap (if not present), and
232 	 *  (2) the other RX handlers will modify the skb we got.
233 	 *
234 	 * We don't need to, of course, if we aren't going to return
235 	 * the SKB because it has a bad FCS/PLCP checksum.
236 	 */
237 
238 	/* room for the radiotap header based on driver features */
239 	needed_headroom = ieee80211_rx_radiotap_len(local, status);
240 
241 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
242 		present_fcs_len = FCS_LEN;
243 
244 	/* make sure hdr->frame_control is on the linear part */
245 	if (!pskb_may_pull(origskb, 2)) {
246 		dev_kfree_skb(origskb);
247 		return NULL;
248 	}
249 
250 	if (!local->monitors) {
251 		if (should_drop_frame(origskb, present_fcs_len)) {
252 			dev_kfree_skb(origskb);
253 			return NULL;
254 		}
255 
256 		return remove_monitor_info(local, origskb);
257 	}
258 
259 	if (should_drop_frame(origskb, present_fcs_len)) {
260 		/* only need to expand headroom if necessary */
261 		skb = origskb;
262 		origskb = NULL;
263 
264 		/*
265 		 * This shouldn't trigger often because most devices have an
266 		 * RX header they pull before we get here, and that should
267 		 * be big enough for our radiotap information. We should
268 		 * probably export the length to drivers so that we can have
269 		 * them allocate enough headroom to start with.
270 		 */
271 		if (skb_headroom(skb) < needed_headroom &&
272 		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
273 			dev_kfree_skb(skb);
274 			return NULL;
275 		}
276 	} else {
277 		/*
278 		 * Need to make a copy and possibly remove radiotap header
279 		 * and FCS from the original.
280 		 */
281 		skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
282 
283 		origskb = remove_monitor_info(local, origskb);
284 
285 		if (!skb)
286 			return origskb;
287 	}
288 
289 	/* prepend radiotap information */
290 	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
291 
292 	skb_reset_mac_header(skb);
293 	skb->ip_summed = CHECKSUM_UNNECESSARY;
294 	skb->pkt_type = PACKET_OTHERHOST;
295 	skb->protocol = htons(ETH_P_802_2);
296 
297 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
298 		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
299 			continue;
300 
301 		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
302 			continue;
303 
304 		if (!ieee80211_sdata_running(sdata))
305 			continue;
306 
307 		if (prev_dev) {
308 			skb2 = skb_clone(skb, GFP_ATOMIC);
309 			if (skb2) {
310 				skb2->dev = prev_dev;
311 				netif_receive_skb(skb2);
312 			}
313 		}
314 
315 		prev_dev = sdata->dev;
316 		sdata->dev->stats.rx_packets++;
317 		sdata->dev->stats.rx_bytes += skb->len;
318 	}
319 
320 	if (prev_dev) {
321 		skb->dev = prev_dev;
322 		netif_receive_skb(skb);
323 	} else
324 		dev_kfree_skb(skb);
325 
326 	return origskb;
327 }
328 
329 
330 static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
331 {
332 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
333 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
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 			status->rx_flags |= IEEE80211_RX_AMSDU;
343 	} else {
344 		/*
345 		 * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
346 		 *
347 		 *	Sequence numbers for management frames, QoS data
348 		 *	frames with a broadcast/multicast address in the
349 		 *	Address 1 field, and all non-QoS data frames sent
350 		 *	by QoS STAs are assigned using an additional single
351 		 *	modulo-4096 counter, [...]
352 		 *
353 		 * We also use that counter for non-QoS STAs.
354 		 */
355 		tid = NUM_RX_DATA_QUEUES - 1;
356 	}
357 
358 	rx->queue = tid;
359 	/* Set skb->priority to 1d tag if highest order bit of TID is not set.
360 	 * For now, set skb->priority to 0 for other cases. */
361 	rx->skb->priority = (tid > 7) ? 0 : tid;
362 }
363 
364 /**
365  * DOC: Packet alignment
366  *
367  * Drivers always need to pass packets that are aligned to two-byte boundaries
368  * to the stack.
369  *
370  * Additionally, should, if possible, align the payload data in a way that
371  * guarantees that the contained IP header is aligned to a four-byte
372  * boundary. In the case of regular frames, this simply means aligning the
373  * payload to a four-byte boundary (because either the IP header is directly
374  * contained, or IV/RFC1042 headers that have a length divisible by four are
375  * in front of it).  If the payload data is not properly aligned and the
376  * architecture doesn't support efficient unaligned operations, mac80211
377  * will align the data.
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 between 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 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
392 	WARN_ONCE((unsigned long)rx->skb->data & 1,
393 		  "unaligned packet at 0x%p\n", rx->skb->data);
394 #endif
395 }
396 
397 
398 /* rx handlers */
399 
400 static ieee80211_rx_result debug_noinline
401 ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
402 {
403 	struct ieee80211_local *local = rx->local;
404 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
405 	struct sk_buff *skb = rx->skb;
406 
407 	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
408 		   !local->sched_scanning))
409 		return RX_CONTINUE;
410 
411 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
412 	    test_bit(SCAN_SW_SCANNING, &local->scanning) ||
413 	    local->sched_scanning)
414 		return ieee80211_scan_rx(rx->sdata, skb);
415 
416 	/* scanning finished during invoking of handlers */
417 	I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
418 	return RX_DROP_UNUSABLE;
419 }
420 
421 
422 static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
423 {
424 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
425 
426 	if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
427 		return 0;
428 
429 	return ieee80211_is_robust_mgmt_frame(hdr);
430 }
431 
432 
433 static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
434 {
435 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
436 
437 	if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
438 		return 0;
439 
440 	return ieee80211_is_robust_mgmt_frame(hdr);
441 }
442 
443 
444 /* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
445 static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
446 {
447 	struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
448 	struct ieee80211_mmie *mmie;
449 
450 	if (skb->len < 24 + sizeof(*mmie) ||
451 	    !is_multicast_ether_addr(hdr->da))
452 		return -1;
453 
454 	if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
455 		return -1; /* not a robust management frame */
456 
457 	mmie = (struct ieee80211_mmie *)
458 		(skb->data + skb->len - sizeof(*mmie));
459 	if (mmie->element_id != WLAN_EID_MMIE ||
460 	    mmie->length != sizeof(*mmie) - 2)
461 		return -1;
462 
463 	return le16_to_cpu(mmie->key_id);
464 }
465 
466 
467 static ieee80211_rx_result
468 ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
469 {
470 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
471 	unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
472 	char *dev_addr = rx->sdata->vif.addr;
473 
474 	if (ieee80211_is_data(hdr->frame_control)) {
475 		if (is_multicast_ether_addr(hdr->addr1)) {
476 			if (ieee80211_has_tods(hdr->frame_control) ||
477 				!ieee80211_has_fromds(hdr->frame_control))
478 				return RX_DROP_MONITOR;
479 			if (memcmp(hdr->addr3, dev_addr, ETH_ALEN) == 0)
480 				return RX_DROP_MONITOR;
481 		} else {
482 			if (!ieee80211_has_a4(hdr->frame_control))
483 				return RX_DROP_MONITOR;
484 			if (memcmp(hdr->addr4, dev_addr, ETH_ALEN) == 0)
485 				return RX_DROP_MONITOR;
486 		}
487 	}
488 
489 	/* If there is not an established peer link and this is not a peer link
490 	 * establisment frame, beacon or probe, drop the frame.
491 	 */
492 
493 	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
494 		struct ieee80211_mgmt *mgmt;
495 
496 		if (!ieee80211_is_mgmt(hdr->frame_control))
497 			return RX_DROP_MONITOR;
498 
499 		if (ieee80211_is_action(hdr->frame_control)) {
500 			u8 category;
501 			mgmt = (struct ieee80211_mgmt *)hdr;
502 			category = mgmt->u.action.category;
503 			if (category != WLAN_CATEGORY_MESH_ACTION &&
504 				category != WLAN_CATEGORY_SELF_PROTECTED)
505 				return RX_DROP_MONITOR;
506 			return RX_CONTINUE;
507 		}
508 
509 		if (ieee80211_is_probe_req(hdr->frame_control) ||
510 		    ieee80211_is_probe_resp(hdr->frame_control) ||
511 		    ieee80211_is_beacon(hdr->frame_control) ||
512 		    ieee80211_is_auth(hdr->frame_control))
513 			return RX_CONTINUE;
514 
515 		return RX_DROP_MONITOR;
516 
517 	}
518 
519 #define msh_h_get(h, l) ((struct ieee80211s_hdr *) ((u8 *)h + l))
520 
521 	if (ieee80211_is_data(hdr->frame_control) &&
522 	    is_multicast_ether_addr(hdr->addr1) &&
523 	    mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
524 		return RX_DROP_MONITOR;
525 #undef msh_h_get
526 
527 	return RX_CONTINUE;
528 }
529 
530 #define SEQ_MODULO 0x1000
531 #define SEQ_MASK   0xfff
532 
533 static inline int seq_less(u16 sq1, u16 sq2)
534 {
535 	return ((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1);
536 }
537 
538 static inline u16 seq_inc(u16 sq)
539 {
540 	return (sq + 1) & SEQ_MASK;
541 }
542 
543 static inline u16 seq_sub(u16 sq1, u16 sq2)
544 {
545 	return (sq1 - sq2) & SEQ_MASK;
546 }
547 
548 
549 static void ieee80211_release_reorder_frame(struct ieee80211_hw *hw,
550 					    struct tid_ampdu_rx *tid_agg_rx,
551 					    int index)
552 {
553 	struct ieee80211_local *local = hw_to_local(hw);
554 	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
555 	struct ieee80211_rx_status *status;
556 
557 	lockdep_assert_held(&tid_agg_rx->reorder_lock);
558 
559 	if (!skb)
560 		goto no_frame;
561 
562 	/* release the frame from the reorder ring buffer */
563 	tid_agg_rx->stored_mpdu_num--;
564 	tid_agg_rx->reorder_buf[index] = NULL;
565 	status = IEEE80211_SKB_RXCB(skb);
566 	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
567 	skb_queue_tail(&local->rx_skb_queue, skb);
568 
569 no_frame:
570 	tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
571 }
572 
573 static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw,
574 					     struct tid_ampdu_rx *tid_agg_rx,
575 					     u16 head_seq_num)
576 {
577 	int index;
578 
579 	lockdep_assert_held(&tid_agg_rx->reorder_lock);
580 
581 	while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
582 		index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
583 							tid_agg_rx->buf_size;
584 		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
585 	}
586 }
587 
588 /*
589  * Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If
590  * the skb was added to the buffer longer than this time ago, the earlier
591  * frames that have not yet been received are assumed to be lost and the skb
592  * can be released for processing. This may also release other skb's from the
593  * reorder buffer if there are no additional gaps between the frames.
594  *
595  * Callers must hold tid_agg_rx->reorder_lock.
596  */
597 #define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
598 
599 static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
600 					  struct tid_ampdu_rx *tid_agg_rx)
601 {
602 	int index, j;
603 
604 	lockdep_assert_held(&tid_agg_rx->reorder_lock);
605 
606 	/* release the buffer until next missing frame */
607 	index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
608 						tid_agg_rx->buf_size;
609 	if (!tid_agg_rx->reorder_buf[index] &&
610 	    tid_agg_rx->stored_mpdu_num > 1) {
611 		/*
612 		 * No buffers ready to be released, but check whether any
613 		 * frames in the reorder buffer have timed out.
614 		 */
615 		int skipped = 1;
616 		for (j = (index + 1) % tid_agg_rx->buf_size; j != index;
617 		     j = (j + 1) % tid_agg_rx->buf_size) {
618 			if (!tid_agg_rx->reorder_buf[j]) {
619 				skipped++;
620 				continue;
621 			}
622 			if (skipped &&
623 			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
624 					HT_RX_REORDER_BUF_TIMEOUT))
625 				goto set_release_timer;
626 
627 #ifdef CONFIG_MAC80211_HT_DEBUG
628 			if (net_ratelimit())
629 				wiphy_debug(hw->wiphy,
630 					    "release an RX reorder frame due to timeout on earlier frames\n");
631 #endif
632 			ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
633 
634 			/*
635 			 * Increment the head seq# also for the skipped slots.
636 			 */
637 			tid_agg_rx->head_seq_num =
638 				(tid_agg_rx->head_seq_num + skipped) & SEQ_MASK;
639 			skipped = 0;
640 		}
641 	} else while (tid_agg_rx->reorder_buf[index]) {
642 		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
643 		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
644 							tid_agg_rx->buf_size;
645 	}
646 
647 	if (tid_agg_rx->stored_mpdu_num) {
648 		j = index = seq_sub(tid_agg_rx->head_seq_num,
649 				    tid_agg_rx->ssn) % tid_agg_rx->buf_size;
650 
651 		for (; j != (index - 1) % tid_agg_rx->buf_size;
652 		     j = (j + 1) % tid_agg_rx->buf_size) {
653 			if (tid_agg_rx->reorder_buf[j])
654 				break;
655 		}
656 
657  set_release_timer:
658 
659 		mod_timer(&tid_agg_rx->reorder_timer,
660 			  tid_agg_rx->reorder_time[j] + 1 +
661 			  HT_RX_REORDER_BUF_TIMEOUT);
662 	} else {
663 		del_timer(&tid_agg_rx->reorder_timer);
664 	}
665 }
666 
667 /*
668  * As this function belongs to the RX path it must be under
669  * rcu_read_lock protection. It returns false if the frame
670  * can be processed immediately, true if it was consumed.
671  */
672 static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
673 					     struct tid_ampdu_rx *tid_agg_rx,
674 					     struct sk_buff *skb)
675 {
676 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
677 	u16 sc = le16_to_cpu(hdr->seq_ctrl);
678 	u16 mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
679 	u16 head_seq_num, buf_size;
680 	int index;
681 	bool ret = true;
682 
683 	spin_lock(&tid_agg_rx->reorder_lock);
684 
685 	buf_size = tid_agg_rx->buf_size;
686 	head_seq_num = tid_agg_rx->head_seq_num;
687 
688 	/* frame with out of date sequence number */
689 	if (seq_less(mpdu_seq_num, head_seq_num)) {
690 		dev_kfree_skb(skb);
691 		goto out;
692 	}
693 
694 	/*
695 	 * If frame the sequence number exceeds our buffering window
696 	 * size release some previous frames to make room for this one.
697 	 */
698 	if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) {
699 		head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size));
700 		/* release stored frames up to new head to stack */
701 		ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num);
702 	}
703 
704 	/* Now the new frame is always in the range of the reordering buffer */
705 
706 	index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) % tid_agg_rx->buf_size;
707 
708 	/* check if we already stored this frame */
709 	if (tid_agg_rx->reorder_buf[index]) {
710 		dev_kfree_skb(skb);
711 		goto out;
712 	}
713 
714 	/*
715 	 * If the current MPDU is in the right order and nothing else
716 	 * is stored we can process it directly, no need to buffer it.
717 	 * If it is first but there's something stored, we may be able
718 	 * to release frames after this one.
719 	 */
720 	if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
721 	    tid_agg_rx->stored_mpdu_num == 0) {
722 		tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
723 		ret = false;
724 		goto out;
725 	}
726 
727 	/* put the frame in the reordering buffer */
728 	tid_agg_rx->reorder_buf[index] = skb;
729 	tid_agg_rx->reorder_time[index] = jiffies;
730 	tid_agg_rx->stored_mpdu_num++;
731 	ieee80211_sta_reorder_release(hw, tid_agg_rx);
732 
733  out:
734 	spin_unlock(&tid_agg_rx->reorder_lock);
735 	return ret;
736 }
737 
738 /*
739  * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
740  * true if the MPDU was buffered, false if it should be processed.
741  */
742 static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
743 {
744 	struct sk_buff *skb = rx->skb;
745 	struct ieee80211_local *local = rx->local;
746 	struct ieee80211_hw *hw = &local->hw;
747 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
748 	struct sta_info *sta = rx->sta;
749 	struct tid_ampdu_rx *tid_agg_rx;
750 	u16 sc;
751 	int tid;
752 
753 	if (!ieee80211_is_data_qos(hdr->frame_control))
754 		goto dont_reorder;
755 
756 	/*
757 	 * filter the QoS data rx stream according to
758 	 * STA/TID and check if this STA/TID is on aggregation
759 	 */
760 
761 	if (!sta)
762 		goto dont_reorder;
763 
764 	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
765 
766 	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
767 	if (!tid_agg_rx)
768 		goto dont_reorder;
769 
770 	/* qos null data frames are excluded */
771 	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
772 		goto dont_reorder;
773 
774 	/* new, potentially un-ordered, ampdu frame - process it */
775 
776 	/* reset session timer */
777 	if (tid_agg_rx->timeout)
778 		mod_timer(&tid_agg_rx->session_timer,
779 			  TU_TO_EXP_TIME(tid_agg_rx->timeout));
780 
781 	/* if this mpdu is fragmented - terminate rx aggregation session */
782 	sc = le16_to_cpu(hdr->seq_ctrl);
783 	if (sc & IEEE80211_SCTL_FRAG) {
784 		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
785 		skb_queue_tail(&rx->sdata->skb_queue, skb);
786 		ieee80211_queue_work(&local->hw, &rx->sdata->work);
787 		return;
788 	}
789 
790 	/*
791 	 * No locking needed -- we will only ever process one
792 	 * RX packet at a time, and thus own tid_agg_rx. All
793 	 * other code manipulating it needs to (and does) make
794 	 * sure that we cannot get to it any more before doing
795 	 * anything with it.
796 	 */
797 	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb))
798 		return;
799 
800  dont_reorder:
801 	skb_queue_tail(&local->rx_skb_queue, skb);
802 }
803 
804 static ieee80211_rx_result debug_noinline
805 ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
806 {
807 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
808 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
809 
810 	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
811 	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
812 		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
813 			     rx->sta->last_seq_ctrl[rx->queue] ==
814 			     hdr->seq_ctrl)) {
815 			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
816 				rx->local->dot11FrameDuplicateCount++;
817 				rx->sta->num_duplicates++;
818 			}
819 			return RX_DROP_UNUSABLE;
820 		} else
821 			rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
822 	}
823 
824 	if (unlikely(rx->skb->len < 16)) {
825 		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
826 		return RX_DROP_MONITOR;
827 	}
828 
829 	/* Drop disallowed frame classes based on STA auth/assoc state;
830 	 * IEEE 802.11, Chap 5.5.
831 	 *
832 	 * mac80211 filters only based on association state, i.e. it drops
833 	 * Class 3 frames from not associated stations. hostapd sends
834 	 * deauth/disassoc frames when needed. In addition, hostapd is
835 	 * responsible for filtering on both auth and assoc states.
836 	 */
837 
838 	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
839 		return ieee80211_rx_mesh_check(rx);
840 
841 	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
842 		      ieee80211_is_pspoll(hdr->frame_control)) &&
843 		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
844 		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
845 		     (!rx->sta || !test_sta_flags(rx->sta, WLAN_STA_ASSOC))))
846 		return RX_DROP_MONITOR;
847 
848 	return RX_CONTINUE;
849 }
850 
851 
852 static ieee80211_rx_result debug_noinline
853 ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
854 {
855 	struct sk_buff *skb = rx->skb;
856 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
857 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
858 	int keyidx;
859 	int hdrlen;
860 	ieee80211_rx_result result = RX_DROP_UNUSABLE;
861 	struct ieee80211_key *sta_ptk = NULL;
862 	int mmie_keyidx = -1;
863 	__le16 fc;
864 
865 	/*
866 	 * Key selection 101
867 	 *
868 	 * There are four types of keys:
869 	 *  - GTK (group keys)
870 	 *  - IGTK (group keys for management frames)
871 	 *  - PTK (pairwise keys)
872 	 *  - STK (station-to-station pairwise keys)
873 	 *
874 	 * When selecting a key, we have to distinguish between multicast
875 	 * (including broadcast) and unicast frames, the latter can only
876 	 * use PTKs and STKs while the former always use GTKs and IGTKs.
877 	 * Unless, of course, actual WEP keys ("pre-RSNA") are used, then
878 	 * unicast frames can also use key indices like GTKs. Hence, if we
879 	 * don't have a PTK/STK we check the key index for a WEP key.
880 	 *
881 	 * Note that in a regular BSS, multicast frames are sent by the
882 	 * AP only, associated stations unicast the frame to the AP first
883 	 * which then multicasts it on their behalf.
884 	 *
885 	 * There is also a slight problem in IBSS mode: GTKs are negotiated
886 	 * with each station, that is something we don't currently handle.
887 	 * The spec seems to expect that one negotiates the same key with
888 	 * every station but there's no such requirement; VLANs could be
889 	 * possible.
890 	 */
891 
892 	/*
893 	 * No point in finding a key and decrypting if the frame is neither
894 	 * addressed to us nor a multicast frame.
895 	 */
896 	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
897 		return RX_CONTINUE;
898 
899 	/* start without a key */
900 	rx->key = NULL;
901 
902 	if (rx->sta)
903 		sta_ptk = rcu_dereference(rx->sta->ptk);
904 
905 	fc = hdr->frame_control;
906 
907 	if (!ieee80211_has_protected(fc))
908 		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
909 
910 	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
911 		rx->key = sta_ptk;
912 		if ((status->flag & RX_FLAG_DECRYPTED) &&
913 		    (status->flag & RX_FLAG_IV_STRIPPED))
914 			return RX_CONTINUE;
915 		/* Skip decryption if the frame is not protected. */
916 		if (!ieee80211_has_protected(fc))
917 			return RX_CONTINUE;
918 	} else if (mmie_keyidx >= 0) {
919 		/* Broadcast/multicast robust management frame / BIP */
920 		if ((status->flag & RX_FLAG_DECRYPTED) &&
921 		    (status->flag & RX_FLAG_IV_STRIPPED))
922 			return RX_CONTINUE;
923 
924 		if (mmie_keyidx < NUM_DEFAULT_KEYS ||
925 		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
926 			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
927 		if (rx->sta)
928 			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
929 		if (!rx->key)
930 			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
931 	} else if (!ieee80211_has_protected(fc)) {
932 		/*
933 		 * The frame was not protected, so skip decryption. However, we
934 		 * need to set rx->key if there is a key that could have been
935 		 * used so that the frame may be dropped if encryption would
936 		 * have been expected.
937 		 */
938 		struct ieee80211_key *key = NULL;
939 		struct ieee80211_sub_if_data *sdata = rx->sdata;
940 		int i;
941 
942 		if (ieee80211_is_mgmt(fc) &&
943 		    is_multicast_ether_addr(hdr->addr1) &&
944 		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
945 			rx->key = key;
946 		else {
947 			if (rx->sta) {
948 				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
949 					key = rcu_dereference(rx->sta->gtk[i]);
950 					if (key)
951 						break;
952 				}
953 			}
954 			if (!key) {
955 				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
956 					key = rcu_dereference(sdata->keys[i]);
957 					if (key)
958 						break;
959 				}
960 			}
961 			if (key)
962 				rx->key = key;
963 		}
964 		return RX_CONTINUE;
965 	} else {
966 		u8 keyid;
967 		/*
968 		 * The device doesn't give us the IV so we won't be
969 		 * able to look up the key. That's ok though, we
970 		 * don't need to decrypt the frame, we just won't
971 		 * be able to keep statistics accurate.
972 		 * Except for key threshold notifications, should
973 		 * we somehow allow the driver to tell us which key
974 		 * the hardware used if this flag is set?
975 		 */
976 		if ((status->flag & RX_FLAG_DECRYPTED) &&
977 		    (status->flag & RX_FLAG_IV_STRIPPED))
978 			return RX_CONTINUE;
979 
980 		hdrlen = ieee80211_hdrlen(fc);
981 
982 		if (rx->skb->len < 8 + hdrlen)
983 			return RX_DROP_UNUSABLE; /* TODO: count this? */
984 
985 		/*
986 		 * no need to call ieee80211_wep_get_keyidx,
987 		 * it verifies a bunch of things we've done already
988 		 */
989 		skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
990 		keyidx = keyid >> 6;
991 
992 		/* check per-station GTK first, if multicast packet */
993 		if (is_multicast_ether_addr(hdr->addr1) && rx->sta)
994 			rx->key = rcu_dereference(rx->sta->gtk[keyidx]);
995 
996 		/* if not found, try default key */
997 		if (!rx->key) {
998 			rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
999 
1000 			/*
1001 			 * RSNA-protected unicast frames should always be
1002 			 * sent with pairwise or station-to-station keys,
1003 			 * but for WEP we allow using a key index as well.
1004 			 */
1005 			if (rx->key &&
1006 			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP40 &&
1007 			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP104 &&
1008 			    !is_multicast_ether_addr(hdr->addr1))
1009 				rx->key = NULL;
1010 		}
1011 	}
1012 
1013 	if (rx->key) {
1014 		rx->key->tx_rx_count++;
1015 		/* TODO: add threshold stuff again */
1016 	} else {
1017 		return RX_DROP_MONITOR;
1018 	}
1019 
1020 	if (skb_linearize(rx->skb))
1021 		return RX_DROP_UNUSABLE;
1022 	/* the hdr variable is invalid now! */
1023 
1024 	switch (rx->key->conf.cipher) {
1025 	case WLAN_CIPHER_SUITE_WEP40:
1026 	case WLAN_CIPHER_SUITE_WEP104:
1027 		/* Check for weak IVs if possible */
1028 		if (rx->sta && ieee80211_is_data(fc) &&
1029 		    (!(status->flag & RX_FLAG_IV_STRIPPED) ||
1030 		     !(status->flag & RX_FLAG_DECRYPTED)) &&
1031 		    ieee80211_wep_is_weak_iv(rx->skb, rx->key))
1032 			rx->sta->wep_weak_iv_count++;
1033 
1034 		result = ieee80211_crypto_wep_decrypt(rx);
1035 		break;
1036 	case WLAN_CIPHER_SUITE_TKIP:
1037 		result = ieee80211_crypto_tkip_decrypt(rx);
1038 		break;
1039 	case WLAN_CIPHER_SUITE_CCMP:
1040 		result = ieee80211_crypto_ccmp_decrypt(rx);
1041 		break;
1042 	case WLAN_CIPHER_SUITE_AES_CMAC:
1043 		result = ieee80211_crypto_aes_cmac_decrypt(rx);
1044 		break;
1045 	default:
1046 		/*
1047 		 * We can reach here only with HW-only algorithms
1048 		 * but why didn't it decrypt the frame?!
1049 		 */
1050 		return RX_DROP_UNUSABLE;
1051 	}
1052 
1053 	/* either the frame has been decrypted or will be dropped */
1054 	status->flag |= RX_FLAG_DECRYPTED;
1055 
1056 	return result;
1057 }
1058 
1059 static ieee80211_rx_result debug_noinline
1060 ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
1061 {
1062 	struct ieee80211_local *local;
1063 	struct ieee80211_hdr *hdr;
1064 	struct sk_buff *skb;
1065 
1066 	local = rx->local;
1067 	skb = rx->skb;
1068 	hdr = (struct ieee80211_hdr *) skb->data;
1069 
1070 	if (!local->pspolling)
1071 		return RX_CONTINUE;
1072 
1073 	if (!ieee80211_has_fromds(hdr->frame_control))
1074 		/* this is not from AP */
1075 		return RX_CONTINUE;
1076 
1077 	if (!ieee80211_is_data(hdr->frame_control))
1078 		return RX_CONTINUE;
1079 
1080 	if (!ieee80211_has_moredata(hdr->frame_control)) {
1081 		/* AP has no more frames buffered for us */
1082 		local->pspolling = false;
1083 		return RX_CONTINUE;
1084 	}
1085 
1086 	/* more data bit is set, let's request a new frame from the AP */
1087 	ieee80211_send_pspoll(local, rx->sdata);
1088 
1089 	return RX_CONTINUE;
1090 }
1091 
1092 static void ap_sta_ps_start(struct sta_info *sta)
1093 {
1094 	struct ieee80211_sub_if_data *sdata = sta->sdata;
1095 	struct ieee80211_local *local = sdata->local;
1096 
1097 	atomic_inc(&sdata->bss->num_sta_ps);
1098 	set_sta_flags(sta, WLAN_STA_PS_STA);
1099 	if (!(local->hw.flags & IEEE80211_HW_AP_LINK_PS))
1100 		drv_sta_notify(local, sdata, STA_NOTIFY_SLEEP, &sta->sta);
1101 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1102 	printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
1103 	       sdata->name, sta->sta.addr, sta->sta.aid);
1104 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1105 }
1106 
1107 static void ap_sta_ps_end(struct sta_info *sta)
1108 {
1109 	struct ieee80211_sub_if_data *sdata = sta->sdata;
1110 
1111 	atomic_dec(&sdata->bss->num_sta_ps);
1112 
1113 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1114 	printk(KERN_DEBUG "%s: STA %pM aid %d exits power save mode\n",
1115 	       sdata->name, sta->sta.addr, sta->sta.aid);
1116 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1117 
1118 	if (test_sta_flags(sta, WLAN_STA_PS_DRIVER)) {
1119 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1120 		printk(KERN_DEBUG "%s: STA %pM aid %d driver-ps-blocked\n",
1121 		       sdata->name, sta->sta.addr, sta->sta.aid);
1122 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1123 		return;
1124 	}
1125 
1126 	ieee80211_sta_ps_deliver_wakeup(sta);
1127 }
1128 
1129 int ieee80211_sta_ps_transition(struct ieee80211_sta *sta, bool start)
1130 {
1131 	struct sta_info *sta_inf = container_of(sta, struct sta_info, sta);
1132 	bool in_ps;
1133 
1134 	WARN_ON(!(sta_inf->local->hw.flags & IEEE80211_HW_AP_LINK_PS));
1135 
1136 	/* Don't let the same PS state be set twice */
1137 	in_ps = test_sta_flags(sta_inf, WLAN_STA_PS_STA);
1138 	if ((start && in_ps) || (!start && !in_ps))
1139 		return -EINVAL;
1140 
1141 	if (start)
1142 		ap_sta_ps_start(sta_inf);
1143 	else
1144 		ap_sta_ps_end(sta_inf);
1145 
1146 	return 0;
1147 }
1148 EXPORT_SYMBOL(ieee80211_sta_ps_transition);
1149 
1150 static ieee80211_rx_result debug_noinline
1151 ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
1152 {
1153 	struct sta_info *sta = rx->sta;
1154 	struct sk_buff *skb = rx->skb;
1155 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
1156 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1157 
1158 	if (!sta)
1159 		return RX_CONTINUE;
1160 
1161 	/*
1162 	 * Update last_rx only for IBSS packets which are for the current
1163 	 * BSSID to avoid keeping the current IBSS network alive in cases
1164 	 * where other STAs start using different BSSID.
1165 	 */
1166 	if (rx->sdata->vif.type == NL80211_IFTYPE_ADHOC) {
1167 		u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
1168 						NL80211_IFTYPE_ADHOC);
1169 		if (compare_ether_addr(bssid, rx->sdata->u.ibss.bssid) == 0) {
1170 			sta->last_rx = jiffies;
1171 			if (ieee80211_is_data(hdr->frame_control)) {
1172 				sta->last_rx_rate_idx = status->rate_idx;
1173 				sta->last_rx_rate_flag = status->flag;
1174 			}
1175 		}
1176 	} else if (!is_multicast_ether_addr(hdr->addr1)) {
1177 		/*
1178 		 * Mesh beacons will update last_rx when if they are found to
1179 		 * match the current local configuration when processed.
1180 		 */
1181 		sta->last_rx = jiffies;
1182 		if (ieee80211_is_data(hdr->frame_control)) {
1183 			sta->last_rx_rate_idx = status->rate_idx;
1184 			sta->last_rx_rate_flag = status->flag;
1185 		}
1186 	}
1187 
1188 	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
1189 		return RX_CONTINUE;
1190 
1191 	if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)
1192 		ieee80211_sta_rx_notify(rx->sdata, hdr);
1193 
1194 	sta->rx_fragments++;
1195 	sta->rx_bytes += rx->skb->len;
1196 	sta->last_signal = status->signal;
1197 	ewma_add(&sta->avg_signal, -status->signal);
1198 
1199 	/*
1200 	 * Change STA power saving mode only at the end of a frame
1201 	 * exchange sequence.
1202 	 */
1203 	if (!(sta->local->hw.flags & IEEE80211_HW_AP_LINK_PS) &&
1204 	    !ieee80211_has_morefrags(hdr->frame_control) &&
1205 	    !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
1206 	    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
1207 	     rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)) {
1208 		if (test_sta_flags(sta, WLAN_STA_PS_STA)) {
1209 			/*
1210 			 * Ignore doze->wake transitions that are
1211 			 * indicated by non-data frames, the standard
1212 			 * is unclear here, but for example going to
1213 			 * PS mode and then scanning would cause a
1214 			 * doze->wake transition for the probe request,
1215 			 * and that is clearly undesirable.
1216 			 */
1217 			if (ieee80211_is_data(hdr->frame_control) &&
1218 			    !ieee80211_has_pm(hdr->frame_control))
1219 				ap_sta_ps_end(sta);
1220 		} else {
1221 			if (ieee80211_has_pm(hdr->frame_control))
1222 				ap_sta_ps_start(sta);
1223 		}
1224 	}
1225 
1226 	/*
1227 	 * Drop (qos-)data::nullfunc frames silently, since they
1228 	 * are used only to control station power saving mode.
1229 	 */
1230 	if (ieee80211_is_nullfunc(hdr->frame_control) ||
1231 	    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
1232 		I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
1233 
1234 		/*
1235 		 * If we receive a 4-addr nullfunc frame from a STA
1236 		 * that was not moved to a 4-addr STA vlan yet, drop
1237 		 * the frame to the monitor interface, to make sure
1238 		 * that hostapd sees it
1239 		 */
1240 		if (ieee80211_has_a4(hdr->frame_control) &&
1241 		    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
1242 		     (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
1243 		      !rx->sdata->u.vlan.sta)))
1244 			return RX_DROP_MONITOR;
1245 		/*
1246 		 * Update counter and free packet here to avoid
1247 		 * counting this as a dropped packed.
1248 		 */
1249 		sta->rx_packets++;
1250 		dev_kfree_skb(rx->skb);
1251 		return RX_QUEUED;
1252 	}
1253 
1254 	return RX_CONTINUE;
1255 } /* ieee80211_rx_h_sta_process */
1256 
1257 static inline struct ieee80211_fragment_entry *
1258 ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata,
1259 			 unsigned int frag, unsigned int seq, int rx_queue,
1260 			 struct sk_buff **skb)
1261 {
1262 	struct ieee80211_fragment_entry *entry;
1263 	int idx;
1264 
1265 	idx = sdata->fragment_next;
1266 	entry = &sdata->fragments[sdata->fragment_next++];
1267 	if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX)
1268 		sdata->fragment_next = 0;
1269 
1270 	if (!skb_queue_empty(&entry->skb_list)) {
1271 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
1272 		struct ieee80211_hdr *hdr =
1273 			(struct ieee80211_hdr *) entry->skb_list.next->data;
1274 		printk(KERN_DEBUG "%s: RX reassembly removed oldest "
1275 		       "fragment entry (idx=%d age=%lu seq=%d last_frag=%d "
1276 		       "addr1=%pM addr2=%pM\n",
1277 		       sdata->name, idx,
1278 		       jiffies - entry->first_frag_time, entry->seq,
1279 		       entry->last_frag, hdr->addr1, hdr->addr2);
1280 #endif
1281 		__skb_queue_purge(&entry->skb_list);
1282 	}
1283 
1284 	__skb_queue_tail(&entry->skb_list, *skb); /* no need for locking */
1285 	*skb = NULL;
1286 	entry->first_frag_time = jiffies;
1287 	entry->seq = seq;
1288 	entry->rx_queue = rx_queue;
1289 	entry->last_frag = frag;
1290 	entry->ccmp = 0;
1291 	entry->extra_len = 0;
1292 
1293 	return entry;
1294 }
1295 
1296 static inline struct ieee80211_fragment_entry *
1297 ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata,
1298 			  unsigned int frag, unsigned int seq,
1299 			  int rx_queue, struct ieee80211_hdr *hdr)
1300 {
1301 	struct ieee80211_fragment_entry *entry;
1302 	int i, idx;
1303 
1304 	idx = sdata->fragment_next;
1305 	for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) {
1306 		struct ieee80211_hdr *f_hdr;
1307 
1308 		idx--;
1309 		if (idx < 0)
1310 			idx = IEEE80211_FRAGMENT_MAX - 1;
1311 
1312 		entry = &sdata->fragments[idx];
1313 		if (skb_queue_empty(&entry->skb_list) || entry->seq != seq ||
1314 		    entry->rx_queue != rx_queue ||
1315 		    entry->last_frag + 1 != frag)
1316 			continue;
1317 
1318 		f_hdr = (struct ieee80211_hdr *)entry->skb_list.next->data;
1319 
1320 		/*
1321 		 * Check ftype and addresses are equal, else check next fragment
1322 		 */
1323 		if (((hdr->frame_control ^ f_hdr->frame_control) &
1324 		     cpu_to_le16(IEEE80211_FCTL_FTYPE)) ||
1325 		    compare_ether_addr(hdr->addr1, f_hdr->addr1) != 0 ||
1326 		    compare_ether_addr(hdr->addr2, f_hdr->addr2) != 0)
1327 			continue;
1328 
1329 		if (time_after(jiffies, entry->first_frag_time + 2 * HZ)) {
1330 			__skb_queue_purge(&entry->skb_list);
1331 			continue;
1332 		}
1333 		return entry;
1334 	}
1335 
1336 	return NULL;
1337 }
1338 
1339 static ieee80211_rx_result debug_noinline
1340 ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
1341 {
1342 	struct ieee80211_hdr *hdr;
1343 	u16 sc;
1344 	__le16 fc;
1345 	unsigned int frag, seq;
1346 	struct ieee80211_fragment_entry *entry;
1347 	struct sk_buff *skb;
1348 	struct ieee80211_rx_status *status;
1349 
1350 	hdr = (struct ieee80211_hdr *)rx->skb->data;
1351 	fc = hdr->frame_control;
1352 	sc = le16_to_cpu(hdr->seq_ctrl);
1353 	frag = sc & IEEE80211_SCTL_FRAG;
1354 
1355 	if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
1356 		   (rx->skb)->len < 24 ||
1357 		   is_multicast_ether_addr(hdr->addr1))) {
1358 		/* not fragmented */
1359 		goto out;
1360 	}
1361 	I802_DEBUG_INC(rx->local->rx_handlers_fragments);
1362 
1363 	if (skb_linearize(rx->skb))
1364 		return RX_DROP_UNUSABLE;
1365 
1366 	/*
1367 	 *  skb_linearize() might change the skb->data and
1368 	 *  previously cached variables (in this case, hdr) need to
1369 	 *  be refreshed with the new data.
1370 	 */
1371 	hdr = (struct ieee80211_hdr *)rx->skb->data;
1372 	seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
1373 
1374 	if (frag == 0) {
1375 		/* This is the first fragment of a new frame. */
1376 		entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
1377 						 rx->queue, &(rx->skb));
1378 		if (rx->key && rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP &&
1379 		    ieee80211_has_protected(fc)) {
1380 			int queue = ieee80211_is_mgmt(fc) ?
1381 				NUM_RX_DATA_QUEUES : rx->queue;
1382 			/* Store CCMP PN so that we can verify that the next
1383 			 * fragment has a sequential PN value. */
1384 			entry->ccmp = 1;
1385 			memcpy(entry->last_pn,
1386 			       rx->key->u.ccmp.rx_pn[queue],
1387 			       CCMP_PN_LEN);
1388 		}
1389 		return RX_QUEUED;
1390 	}
1391 
1392 	/* This is a fragment for a frame that should already be pending in
1393 	 * fragment cache. Add this fragment to the end of the pending entry.
1394 	 */
1395 	entry = ieee80211_reassemble_find(rx->sdata, frag, seq, rx->queue, hdr);
1396 	if (!entry) {
1397 		I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
1398 		return RX_DROP_MONITOR;
1399 	}
1400 
1401 	/* Verify that MPDUs within one MSDU have sequential PN values.
1402 	 * (IEEE 802.11i, 8.3.3.4.5) */
1403 	if (entry->ccmp) {
1404 		int i;
1405 		u8 pn[CCMP_PN_LEN], *rpn;
1406 		int queue;
1407 		if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_CCMP)
1408 			return RX_DROP_UNUSABLE;
1409 		memcpy(pn, entry->last_pn, CCMP_PN_LEN);
1410 		for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
1411 			pn[i]++;
1412 			if (pn[i])
1413 				break;
1414 		}
1415 		queue = ieee80211_is_mgmt(fc) ?
1416 			NUM_RX_DATA_QUEUES : rx->queue;
1417 		rpn = rx->key->u.ccmp.rx_pn[queue];
1418 		if (memcmp(pn, rpn, CCMP_PN_LEN))
1419 			return RX_DROP_UNUSABLE;
1420 		memcpy(entry->last_pn, pn, CCMP_PN_LEN);
1421 	}
1422 
1423 	skb_pull(rx->skb, ieee80211_hdrlen(fc));
1424 	__skb_queue_tail(&entry->skb_list, rx->skb);
1425 	entry->last_frag = frag;
1426 	entry->extra_len += rx->skb->len;
1427 	if (ieee80211_has_morefrags(fc)) {
1428 		rx->skb = NULL;
1429 		return RX_QUEUED;
1430 	}
1431 
1432 	rx->skb = __skb_dequeue(&entry->skb_list);
1433 	if (skb_tailroom(rx->skb) < entry->extra_len) {
1434 		I802_DEBUG_INC(rx->local->rx_expand_skb_head2);
1435 		if (unlikely(pskb_expand_head(rx->skb, 0, entry->extra_len,
1436 					      GFP_ATOMIC))) {
1437 			I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
1438 			__skb_queue_purge(&entry->skb_list);
1439 			return RX_DROP_UNUSABLE;
1440 		}
1441 	}
1442 	while ((skb = __skb_dequeue(&entry->skb_list))) {
1443 		memcpy(skb_put(rx->skb, skb->len), skb->data, skb->len);
1444 		dev_kfree_skb(skb);
1445 	}
1446 
1447 	/* Complete frame has been reassembled - process it now */
1448 	status = IEEE80211_SKB_RXCB(rx->skb);
1449 	status->rx_flags |= IEEE80211_RX_FRAGMENTED;
1450 
1451  out:
1452 	if (rx->sta)
1453 		rx->sta->rx_packets++;
1454 	if (is_multicast_ether_addr(hdr->addr1))
1455 		rx->local->dot11MulticastReceivedFrameCount++;
1456 	else
1457 		ieee80211_led_rx(rx->local);
1458 	return RX_CONTINUE;
1459 }
1460 
1461 static ieee80211_rx_result debug_noinline
1462 ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
1463 {
1464 	struct ieee80211_sub_if_data *sdata = rx->sdata;
1465 	__le16 fc = ((struct ieee80211_hdr *)rx->skb->data)->frame_control;
1466 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
1467 
1468 	if (likely(!rx->sta || !ieee80211_is_pspoll(fc) ||
1469 		   !(status->rx_flags & IEEE80211_RX_RA_MATCH)))
1470 		return RX_CONTINUE;
1471 
1472 	if ((sdata->vif.type != NL80211_IFTYPE_AP) &&
1473 	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
1474 		return RX_DROP_UNUSABLE;
1475 
1476 	if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
1477 		ieee80211_sta_ps_deliver_poll_response(rx->sta);
1478 	else
1479 		set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
1480 
1481 	/* Free PS Poll skb here instead of returning RX_DROP that would
1482 	 * count as an dropped frame. */
1483 	dev_kfree_skb(rx->skb);
1484 
1485 	return RX_QUEUED;
1486 }
1487 
1488 static ieee80211_rx_result debug_noinline
1489 ieee80211_rx_h_remove_qos_control(struct ieee80211_rx_data *rx)
1490 {
1491 	u8 *data = rx->skb->data;
1492 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)data;
1493 
1494 	if (!ieee80211_is_data_qos(hdr->frame_control))
1495 		return RX_CONTINUE;
1496 
1497 	/* remove the qos control field, update frame type and meta-data */
1498 	memmove(data + IEEE80211_QOS_CTL_LEN, data,
1499 		ieee80211_hdrlen(hdr->frame_control) - IEEE80211_QOS_CTL_LEN);
1500 	hdr = (struct ieee80211_hdr *)skb_pull(rx->skb, IEEE80211_QOS_CTL_LEN);
1501 	/* change frame type to non QOS */
1502 	hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
1503 
1504 	return RX_CONTINUE;
1505 }
1506 
1507 static int
1508 ieee80211_802_1x_port_control(struct ieee80211_rx_data *rx)
1509 {
1510 	if (unlikely(!rx->sta ||
1511 	    !test_sta_flags(rx->sta, WLAN_STA_AUTHORIZED)))
1512 		return -EACCES;
1513 
1514 	return 0;
1515 }
1516 
1517 static int
1518 ieee80211_drop_unencrypted(struct ieee80211_rx_data *rx, __le16 fc)
1519 {
1520 	struct sk_buff *skb = rx->skb;
1521 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
1522 
1523 	/*
1524 	 * Pass through unencrypted frames if the hardware has
1525 	 * decrypted them already.
1526 	 */
1527 	if (status->flag & RX_FLAG_DECRYPTED)
1528 		return 0;
1529 
1530 	/* Drop unencrypted frames if key is set. */
1531 	if (unlikely(!ieee80211_has_protected(fc) &&
1532 		     !ieee80211_is_nullfunc(fc) &&
1533 		     ieee80211_is_data(fc) &&
1534 		     (rx->key || rx->sdata->drop_unencrypted)))
1535 		return -EACCES;
1536 
1537 	return 0;
1538 }
1539 
1540 static int
1541 ieee80211_drop_unencrypted_mgmt(struct ieee80211_rx_data *rx)
1542 {
1543 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
1544 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
1545 	__le16 fc = hdr->frame_control;
1546 
1547 	/*
1548 	 * Pass through unencrypted frames if the hardware has
1549 	 * decrypted them already.
1550 	 */
1551 	if (status->flag & RX_FLAG_DECRYPTED)
1552 		return 0;
1553 
1554 	if (rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP)) {
1555 		if (unlikely(!ieee80211_has_protected(fc) &&
1556 			     ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
1557 			     rx->key)) {
1558 			if (ieee80211_is_deauth(fc))
1559 				cfg80211_send_unprot_deauth(rx->sdata->dev,
1560 							    rx->skb->data,
1561 							    rx->skb->len);
1562 			else if (ieee80211_is_disassoc(fc))
1563 				cfg80211_send_unprot_disassoc(rx->sdata->dev,
1564 							      rx->skb->data,
1565 							      rx->skb->len);
1566 			return -EACCES;
1567 		}
1568 		/* BIP does not use Protected field, so need to check MMIE */
1569 		if (unlikely(ieee80211_is_multicast_robust_mgmt_frame(rx->skb) &&
1570 			     ieee80211_get_mmie_keyidx(rx->skb) < 0)) {
1571 			if (ieee80211_is_deauth(fc))
1572 				cfg80211_send_unprot_deauth(rx->sdata->dev,
1573 							    rx->skb->data,
1574 							    rx->skb->len);
1575 			else if (ieee80211_is_disassoc(fc))
1576 				cfg80211_send_unprot_disassoc(rx->sdata->dev,
1577 							      rx->skb->data,
1578 							      rx->skb->len);
1579 			return -EACCES;
1580 		}
1581 		/*
1582 		 * When using MFP, Action frames are not allowed prior to
1583 		 * having configured keys.
1584 		 */
1585 		if (unlikely(ieee80211_is_action(fc) && !rx->key &&
1586 			     ieee80211_is_robust_mgmt_frame(
1587 				     (struct ieee80211_hdr *) rx->skb->data)))
1588 			return -EACCES;
1589 	}
1590 
1591 	return 0;
1592 }
1593 
1594 static int
1595 __ieee80211_data_to_8023(struct ieee80211_rx_data *rx, bool *port_control)
1596 {
1597 	struct ieee80211_sub_if_data *sdata = rx->sdata;
1598 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
1599 	bool check_port_control = false;
1600 	struct ethhdr *ehdr;
1601 	int ret;
1602 
1603 	*port_control = false;
1604 	if (ieee80211_has_a4(hdr->frame_control) &&
1605 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->u.vlan.sta)
1606 		return -1;
1607 
1608 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
1609 	    !!sdata->u.mgd.use_4addr != !!ieee80211_has_a4(hdr->frame_control)) {
1610 
1611 		if (!sdata->u.mgd.use_4addr)
1612 			return -1;
1613 		else
1614 			check_port_control = true;
1615 	}
1616 
1617 	if (is_multicast_ether_addr(hdr->addr1) &&
1618 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN && sdata->u.vlan.sta)
1619 		return -1;
1620 
1621 	ret = ieee80211_data_to_8023(rx->skb, sdata->vif.addr, sdata->vif.type);
1622 	if (ret < 0)
1623 		return ret;
1624 
1625 	ehdr = (struct ethhdr *) rx->skb->data;
1626 	if (ehdr->h_proto == rx->sdata->control_port_protocol)
1627 		*port_control = true;
1628 	else if (check_port_control)
1629 		return -1;
1630 
1631 	return 0;
1632 }
1633 
1634 /*
1635  * requires that rx->skb is a frame with ethernet header
1636  */
1637 static bool ieee80211_frame_allowed(struct ieee80211_rx_data *rx, __le16 fc)
1638 {
1639 	static const u8 pae_group_addr[ETH_ALEN] __aligned(2)
1640 		= { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x03 };
1641 	struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
1642 
1643 	/*
1644 	 * Allow EAPOL frames to us/the PAE group address regardless
1645 	 * of whether the frame was encrypted or not.
1646 	 */
1647 	if (ehdr->h_proto == rx->sdata->control_port_protocol &&
1648 	    (compare_ether_addr(ehdr->h_dest, rx->sdata->vif.addr) == 0 ||
1649 	     compare_ether_addr(ehdr->h_dest, pae_group_addr) == 0))
1650 		return true;
1651 
1652 	if (ieee80211_802_1x_port_control(rx) ||
1653 	    ieee80211_drop_unencrypted(rx, fc))
1654 		return false;
1655 
1656 	return true;
1657 }
1658 
1659 /*
1660  * requires that rx->skb is a frame with ethernet header
1661  */
1662 static void
1663 ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
1664 {
1665 	struct ieee80211_sub_if_data *sdata = rx->sdata;
1666 	struct net_device *dev = sdata->dev;
1667 	struct sk_buff *skb, *xmit_skb;
1668 	struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
1669 	struct sta_info *dsta;
1670 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
1671 
1672 	skb = rx->skb;
1673 	xmit_skb = NULL;
1674 
1675 	if ((sdata->vif.type == NL80211_IFTYPE_AP ||
1676 	     sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
1677 	    !(sdata->flags & IEEE80211_SDATA_DONT_BRIDGE_PACKETS) &&
1678 	    (status->rx_flags & IEEE80211_RX_RA_MATCH) &&
1679 	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->u.vlan.sta)) {
1680 		if (is_multicast_ether_addr(ehdr->h_dest)) {
1681 			/*
1682 			 * send multicast frames both to higher layers in
1683 			 * local net stack and back to the wireless medium
1684 			 */
1685 			xmit_skb = skb_copy(skb, GFP_ATOMIC);
1686 			if (!xmit_skb && net_ratelimit())
1687 				printk(KERN_DEBUG "%s: failed to clone "
1688 				       "multicast frame\n", dev->name);
1689 		} else {
1690 			dsta = sta_info_get(sdata, skb->data);
1691 			if (dsta) {
1692 				/*
1693 				 * The destination station is associated to
1694 				 * this AP (in this VLAN), so send the frame
1695 				 * directly to it and do not pass it to local
1696 				 * net stack.
1697 				 */
1698 				xmit_skb = skb;
1699 				skb = NULL;
1700 			}
1701 		}
1702 	}
1703 
1704 	if (skb) {
1705 		int align __maybe_unused;
1706 
1707 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1708 		/*
1709 		 * 'align' will only take the values 0 or 2 here
1710 		 * since all frames are required to be aligned
1711 		 * to 2-byte boundaries when being passed to
1712 		 * mac80211. That also explains the __skb_push()
1713 		 * below.
1714 		 */
1715 		align = ((unsigned long)(skb->data + sizeof(struct ethhdr))) & 3;
1716 		if (align) {
1717 			if (WARN_ON(skb_headroom(skb) < 3)) {
1718 				dev_kfree_skb(skb);
1719 				skb = NULL;
1720 			} else {
1721 				u8 *data = skb->data;
1722 				size_t len = skb_headlen(skb);
1723 				skb->data -= align;
1724 				memmove(skb->data, data, len);
1725 				skb_set_tail_pointer(skb, len);
1726 			}
1727 		}
1728 #endif
1729 
1730 		if (skb) {
1731 			/* deliver to local stack */
1732 			skb->protocol = eth_type_trans(skb, dev);
1733 			memset(skb->cb, 0, sizeof(skb->cb));
1734 			netif_receive_skb(skb);
1735 		}
1736 	}
1737 
1738 	if (xmit_skb) {
1739 		/* send to wireless media */
1740 		xmit_skb->protocol = htons(ETH_P_802_3);
1741 		skb_reset_network_header(xmit_skb);
1742 		skb_reset_mac_header(xmit_skb);
1743 		dev_queue_xmit(xmit_skb);
1744 	}
1745 }
1746 
1747 static ieee80211_rx_result debug_noinline
1748 ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
1749 {
1750 	struct net_device *dev = rx->sdata->dev;
1751 	struct sk_buff *skb = rx->skb;
1752 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1753 	__le16 fc = hdr->frame_control;
1754 	struct sk_buff_head frame_list;
1755 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
1756 
1757 	if (unlikely(!ieee80211_is_data(fc)))
1758 		return RX_CONTINUE;
1759 
1760 	if (unlikely(!ieee80211_is_data_present(fc)))
1761 		return RX_DROP_MONITOR;
1762 
1763 	if (!(status->rx_flags & IEEE80211_RX_AMSDU))
1764 		return RX_CONTINUE;
1765 
1766 	if (ieee80211_has_a4(hdr->frame_control) &&
1767 	    rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
1768 	    !rx->sdata->u.vlan.sta)
1769 		return RX_DROP_UNUSABLE;
1770 
1771 	if (is_multicast_ether_addr(hdr->addr1) &&
1772 	    ((rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
1773 	      rx->sdata->u.vlan.sta) ||
1774 	     (rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
1775 	      rx->sdata->u.mgd.use_4addr)))
1776 		return RX_DROP_UNUSABLE;
1777 
1778 	skb->dev = dev;
1779 	__skb_queue_head_init(&frame_list);
1780 
1781 	if (skb_linearize(skb))
1782 		return RX_DROP_UNUSABLE;
1783 
1784 	ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
1785 				 rx->sdata->vif.type,
1786 				 rx->local->hw.extra_tx_headroom, true);
1787 
1788 	while (!skb_queue_empty(&frame_list)) {
1789 		rx->skb = __skb_dequeue(&frame_list);
1790 
1791 		if (!ieee80211_frame_allowed(rx, fc)) {
1792 			dev_kfree_skb(rx->skb);
1793 			continue;
1794 		}
1795 		dev->stats.rx_packets++;
1796 		dev->stats.rx_bytes += rx->skb->len;
1797 
1798 		ieee80211_deliver_skb(rx);
1799 	}
1800 
1801 	return RX_QUEUED;
1802 }
1803 
1804 #ifdef CONFIG_MAC80211_MESH
1805 static ieee80211_rx_result
1806 ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
1807 {
1808 	struct ieee80211_hdr *hdr;
1809 	struct ieee80211s_hdr *mesh_hdr;
1810 	unsigned int hdrlen;
1811 	struct sk_buff *skb = rx->skb, *fwd_skb;
1812 	struct ieee80211_local *local = rx->local;
1813 	struct ieee80211_sub_if_data *sdata = rx->sdata;
1814 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
1815 
1816 	hdr = (struct ieee80211_hdr *) skb->data;
1817 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
1818 	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
1819 
1820 	if (!ieee80211_is_data(hdr->frame_control))
1821 		return RX_CONTINUE;
1822 
1823 	if (!mesh_hdr->ttl)
1824 		/* illegal frame */
1825 		return RX_DROP_MONITOR;
1826 
1827 	if (mesh_hdr->flags & MESH_FLAGS_AE) {
1828 		struct mesh_path *mppath;
1829 		char *proxied_addr;
1830 		char *mpp_addr;
1831 
1832 		if (is_multicast_ether_addr(hdr->addr1)) {
1833 			mpp_addr = hdr->addr3;
1834 			proxied_addr = mesh_hdr->eaddr1;
1835 		} else {
1836 			mpp_addr = hdr->addr4;
1837 			proxied_addr = mesh_hdr->eaddr2;
1838 		}
1839 
1840 		rcu_read_lock();
1841 		mppath = mpp_path_lookup(proxied_addr, sdata);
1842 		if (!mppath) {
1843 			mpp_path_add(proxied_addr, mpp_addr, sdata);
1844 		} else {
1845 			spin_lock_bh(&mppath->state_lock);
1846 			if (compare_ether_addr(mppath->mpp, mpp_addr) != 0)
1847 				memcpy(mppath->mpp, mpp_addr, ETH_ALEN);
1848 			spin_unlock_bh(&mppath->state_lock);
1849 		}
1850 		rcu_read_unlock();
1851 	}
1852 
1853 	/* Frame has reached destination.  Don't forward */
1854 	if (!is_multicast_ether_addr(hdr->addr1) &&
1855 	    compare_ether_addr(sdata->vif.addr, hdr->addr3) == 0)
1856 		return RX_CONTINUE;
1857 
1858 	mesh_hdr->ttl--;
1859 
1860 	if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
1861 		if (!mesh_hdr->ttl)
1862 			IEEE80211_IFSTA_MESH_CTR_INC(&rx->sdata->u.mesh,
1863 						     dropped_frames_ttl);
1864 		else {
1865 			struct ieee80211_hdr *fwd_hdr;
1866 			struct ieee80211_tx_info *info;
1867 
1868 			fwd_skb = skb_copy(skb, GFP_ATOMIC);
1869 
1870 			if (!fwd_skb && net_ratelimit())
1871 				printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
1872 						   sdata->name);
1873 			if (!fwd_skb)
1874 				goto out;
1875 
1876 			fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
1877 			memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
1878 			info = IEEE80211_SKB_CB(fwd_skb);
1879 			memset(info, 0, sizeof(*info));
1880 			info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1881 			info->control.vif = &rx->sdata->vif;
1882 			skb_set_queue_mapping(skb,
1883 				ieee80211_select_queue(rx->sdata, fwd_skb));
1884 			ieee80211_set_qos_hdr(local, skb);
1885 			if (is_multicast_ether_addr(fwd_hdr->addr1))
1886 				IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1887 								fwded_mcast);
1888 			else {
1889 				int err;
1890 				/*
1891 				 * Save TA to addr1 to send TA a path error if a
1892 				 * suitable next hop is not found
1893 				 */
1894 				memcpy(fwd_hdr->addr1, fwd_hdr->addr2,
1895 						ETH_ALEN);
1896 				err = mesh_nexthop_lookup(fwd_skb, sdata);
1897 				/* Failed to immediately resolve next hop:
1898 				 * fwded frame was dropped or will be added
1899 				 * later to the pending skb queue.  */
1900 				if (err)
1901 					return RX_DROP_MONITOR;
1902 
1903 				IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1904 								fwded_unicast);
1905 			}
1906 			IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
1907 						     fwded_frames);
1908 			ieee80211_add_pending_skb(local, fwd_skb);
1909 		}
1910 	}
1911 
1912  out:
1913 	if (is_multicast_ether_addr(hdr->addr1) ||
1914 	    sdata->dev->flags & IFF_PROMISC)
1915 		return RX_CONTINUE;
1916 	else
1917 		return RX_DROP_MONITOR;
1918 }
1919 #endif
1920 
1921 static ieee80211_rx_result debug_noinline
1922 ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
1923 {
1924 	struct ieee80211_sub_if_data *sdata = rx->sdata;
1925 	struct ieee80211_local *local = rx->local;
1926 	struct net_device *dev = sdata->dev;
1927 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
1928 	__le16 fc = hdr->frame_control;
1929 	bool port_control;
1930 	int err;
1931 
1932 	if (unlikely(!ieee80211_is_data(hdr->frame_control)))
1933 		return RX_CONTINUE;
1934 
1935 	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
1936 		return RX_DROP_MONITOR;
1937 
1938 	/*
1939 	 * Allow the cooked monitor interface of an AP to see 4-addr frames so
1940 	 * that a 4-addr station can be detected and moved into a separate VLAN
1941 	 */
1942 	if (ieee80211_has_a4(hdr->frame_control) &&
1943 	    sdata->vif.type == NL80211_IFTYPE_AP)
1944 		return RX_DROP_MONITOR;
1945 
1946 	err = __ieee80211_data_to_8023(rx, &port_control);
1947 	if (unlikely(err))
1948 		return RX_DROP_UNUSABLE;
1949 
1950 	if (!ieee80211_frame_allowed(rx, fc))
1951 		return RX_DROP_MONITOR;
1952 
1953 	if (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
1954 	    unlikely(port_control) && sdata->bss) {
1955 		sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
1956 				     u.ap);
1957 		dev = sdata->dev;
1958 		rx->sdata = sdata;
1959 	}
1960 
1961 	rx->skb->dev = dev;
1962 
1963 	dev->stats.rx_packets++;
1964 	dev->stats.rx_bytes += rx->skb->len;
1965 
1966 	if (local->ps_sdata && local->hw.conf.dynamic_ps_timeout > 0 &&
1967 	    !is_multicast_ether_addr(
1968 		    ((struct ethhdr *)rx->skb->data)->h_dest) &&
1969 	    (!local->scanning &&
1970 	     !test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state))) {
1971 			mod_timer(&local->dynamic_ps_timer, jiffies +
1972 			 msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
1973 	}
1974 
1975 	ieee80211_deliver_skb(rx);
1976 
1977 	return RX_QUEUED;
1978 }
1979 
1980 static ieee80211_rx_result debug_noinline
1981 ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx)
1982 {
1983 	struct ieee80211_local *local = rx->local;
1984 	struct ieee80211_hw *hw = &local->hw;
1985 	struct sk_buff *skb = rx->skb;
1986 	struct ieee80211_bar *bar = (struct ieee80211_bar *)skb->data;
1987 	struct tid_ampdu_rx *tid_agg_rx;
1988 	u16 start_seq_num;
1989 	u16 tid;
1990 
1991 	if (likely(!ieee80211_is_ctl(bar->frame_control)))
1992 		return RX_CONTINUE;
1993 
1994 	if (ieee80211_is_back_req(bar->frame_control)) {
1995 		struct {
1996 			__le16 control, start_seq_num;
1997 		} __packed bar_data;
1998 
1999 		if (!rx->sta)
2000 			return RX_DROP_MONITOR;
2001 
2002 		if (skb_copy_bits(skb, offsetof(struct ieee80211_bar, control),
2003 				  &bar_data, sizeof(bar_data)))
2004 			return RX_DROP_MONITOR;
2005 
2006 		tid = le16_to_cpu(bar_data.control) >> 12;
2007 
2008 		tid_agg_rx = rcu_dereference(rx->sta->ampdu_mlme.tid_rx[tid]);
2009 		if (!tid_agg_rx)
2010 			return RX_DROP_MONITOR;
2011 
2012 		start_seq_num = le16_to_cpu(bar_data.start_seq_num) >> 4;
2013 
2014 		/* reset session timer */
2015 		if (tid_agg_rx->timeout)
2016 			mod_timer(&tid_agg_rx->session_timer,
2017 				  TU_TO_EXP_TIME(tid_agg_rx->timeout));
2018 
2019 		spin_lock(&tid_agg_rx->reorder_lock);
2020 		/* release stored frames up to start of BAR */
2021 		ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num);
2022 		spin_unlock(&tid_agg_rx->reorder_lock);
2023 
2024 		kfree_skb(skb);
2025 		return RX_QUEUED;
2026 	}
2027 
2028 	/*
2029 	 * After this point, we only want management frames,
2030 	 * so we can drop all remaining control frames to
2031 	 * cooked monitor interfaces.
2032 	 */
2033 	return RX_DROP_MONITOR;
2034 }
2035 
2036 static void ieee80211_process_sa_query_req(struct ieee80211_sub_if_data *sdata,
2037 					   struct ieee80211_mgmt *mgmt,
2038 					   size_t len)
2039 {
2040 	struct ieee80211_local *local = sdata->local;
2041 	struct sk_buff *skb;
2042 	struct ieee80211_mgmt *resp;
2043 
2044 	if (compare_ether_addr(mgmt->da, sdata->vif.addr) != 0) {
2045 		/* Not to own unicast address */
2046 		return;
2047 	}
2048 
2049 	if (compare_ether_addr(mgmt->sa, sdata->u.mgd.bssid) != 0 ||
2050 	    compare_ether_addr(mgmt->bssid, sdata->u.mgd.bssid) != 0) {
2051 		/* Not from the current AP or not associated yet. */
2052 		return;
2053 	}
2054 
2055 	if (len < 24 + 1 + sizeof(resp->u.action.u.sa_query)) {
2056 		/* Too short SA Query request frame */
2057 		return;
2058 	}
2059 
2060 	skb = dev_alloc_skb(sizeof(*resp) + local->hw.extra_tx_headroom);
2061 	if (skb == NULL)
2062 		return;
2063 
2064 	skb_reserve(skb, local->hw.extra_tx_headroom);
2065 	resp = (struct ieee80211_mgmt *) skb_put(skb, 24);
2066 	memset(resp, 0, 24);
2067 	memcpy(resp->da, mgmt->sa, ETH_ALEN);
2068 	memcpy(resp->sa, sdata->vif.addr, ETH_ALEN);
2069 	memcpy(resp->bssid, sdata->u.mgd.bssid, ETH_ALEN);
2070 	resp->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
2071 					  IEEE80211_STYPE_ACTION);
2072 	skb_put(skb, 1 + sizeof(resp->u.action.u.sa_query));
2073 	resp->u.action.category = WLAN_CATEGORY_SA_QUERY;
2074 	resp->u.action.u.sa_query.action = WLAN_ACTION_SA_QUERY_RESPONSE;
2075 	memcpy(resp->u.action.u.sa_query.trans_id,
2076 	       mgmt->u.action.u.sa_query.trans_id,
2077 	       WLAN_SA_QUERY_TR_ID_LEN);
2078 
2079 	ieee80211_tx_skb(sdata, skb);
2080 }
2081 
2082 static ieee80211_rx_result debug_noinline
2083 ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
2084 {
2085 	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
2086 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
2087 
2088 	/*
2089 	 * From here on, look only at management frames.
2090 	 * Data and control frames are already handled,
2091 	 * and unknown (reserved) frames are useless.
2092 	 */
2093 	if (rx->skb->len < 24)
2094 		return RX_DROP_MONITOR;
2095 
2096 	if (!ieee80211_is_mgmt(mgmt->frame_control))
2097 		return RX_DROP_MONITOR;
2098 
2099 	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
2100 		return RX_DROP_MONITOR;
2101 
2102 	if (ieee80211_drop_unencrypted_mgmt(rx))
2103 		return RX_DROP_UNUSABLE;
2104 
2105 	return RX_CONTINUE;
2106 }
2107 
2108 static ieee80211_rx_result debug_noinline
2109 ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
2110 {
2111 	struct ieee80211_local *local = rx->local;
2112 	struct ieee80211_sub_if_data *sdata = rx->sdata;
2113 	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
2114 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
2115 	int len = rx->skb->len;
2116 
2117 	if (!ieee80211_is_action(mgmt->frame_control))
2118 		return RX_CONTINUE;
2119 
2120 	/* drop too small frames */
2121 	if (len < IEEE80211_MIN_ACTION_SIZE)
2122 		return RX_DROP_UNUSABLE;
2123 
2124 	if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC)
2125 		return RX_DROP_UNUSABLE;
2126 
2127 	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
2128 		return RX_DROP_UNUSABLE;
2129 
2130 	switch (mgmt->u.action.category) {
2131 	case WLAN_CATEGORY_BACK:
2132 		/*
2133 		 * The aggregation code is not prepared to handle
2134 		 * anything but STA/AP due to the BSSID handling;
2135 		 * IBSS could work in the code but isn't supported
2136 		 * by drivers or the standard.
2137 		 */
2138 		if (sdata->vif.type != NL80211_IFTYPE_STATION &&
2139 		    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
2140 		    sdata->vif.type != NL80211_IFTYPE_AP)
2141 			break;
2142 
2143 		/* verify action_code is present */
2144 		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
2145 			break;
2146 
2147 		switch (mgmt->u.action.u.addba_req.action_code) {
2148 		case WLAN_ACTION_ADDBA_REQ:
2149 			if (len < (IEEE80211_MIN_ACTION_SIZE +
2150 				   sizeof(mgmt->u.action.u.addba_req)))
2151 				goto invalid;
2152 			break;
2153 		case WLAN_ACTION_ADDBA_RESP:
2154 			if (len < (IEEE80211_MIN_ACTION_SIZE +
2155 				   sizeof(mgmt->u.action.u.addba_resp)))
2156 				goto invalid;
2157 			break;
2158 		case WLAN_ACTION_DELBA:
2159 			if (len < (IEEE80211_MIN_ACTION_SIZE +
2160 				   sizeof(mgmt->u.action.u.delba)))
2161 				goto invalid;
2162 			break;
2163 		default:
2164 			goto invalid;
2165 		}
2166 
2167 		goto queue;
2168 	case WLAN_CATEGORY_SPECTRUM_MGMT:
2169 		if (local->hw.conf.channel->band != IEEE80211_BAND_5GHZ)
2170 			break;
2171 
2172 		if (sdata->vif.type != NL80211_IFTYPE_STATION)
2173 			break;
2174 
2175 		/* verify action_code is present */
2176 		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
2177 			break;
2178 
2179 		switch (mgmt->u.action.u.measurement.action_code) {
2180 		case WLAN_ACTION_SPCT_MSR_REQ:
2181 			if (len < (IEEE80211_MIN_ACTION_SIZE +
2182 				   sizeof(mgmt->u.action.u.measurement)))
2183 				break;
2184 			ieee80211_process_measurement_req(sdata, mgmt, len);
2185 			goto handled;
2186 		case WLAN_ACTION_SPCT_CHL_SWITCH:
2187 			if (len < (IEEE80211_MIN_ACTION_SIZE +
2188 				   sizeof(mgmt->u.action.u.chan_switch)))
2189 				break;
2190 
2191 			if (sdata->vif.type != NL80211_IFTYPE_STATION)
2192 				break;
2193 
2194 			if (memcmp(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN))
2195 				break;
2196 
2197 			goto queue;
2198 		}
2199 		break;
2200 	case WLAN_CATEGORY_SA_QUERY:
2201 		if (len < (IEEE80211_MIN_ACTION_SIZE +
2202 			   sizeof(mgmt->u.action.u.sa_query)))
2203 			break;
2204 
2205 		switch (mgmt->u.action.u.sa_query.action) {
2206 		case WLAN_ACTION_SA_QUERY_REQUEST:
2207 			if (sdata->vif.type != NL80211_IFTYPE_STATION)
2208 				break;
2209 			ieee80211_process_sa_query_req(sdata, mgmt, len);
2210 			goto handled;
2211 		}
2212 		break;
2213 	case WLAN_CATEGORY_MESH_ACTION:
2214 		if (!ieee80211_vif_is_mesh(&sdata->vif))
2215 			break;
2216 		goto queue;
2217 	case WLAN_CATEGORY_MESH_PATH_SEL:
2218 		if (!mesh_path_sel_is_hwmp(sdata))
2219 			break;
2220 		goto queue;
2221 	}
2222 
2223 	return RX_CONTINUE;
2224 
2225  invalid:
2226 	status->rx_flags |= IEEE80211_RX_MALFORMED_ACTION_FRM;
2227 	/* will return in the next handlers */
2228 	return RX_CONTINUE;
2229 
2230  handled:
2231 	if (rx->sta)
2232 		rx->sta->rx_packets++;
2233 	dev_kfree_skb(rx->skb);
2234 	return RX_QUEUED;
2235 
2236  queue:
2237 	rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
2238 	skb_queue_tail(&sdata->skb_queue, rx->skb);
2239 	ieee80211_queue_work(&local->hw, &sdata->work);
2240 	if (rx->sta)
2241 		rx->sta->rx_packets++;
2242 	return RX_QUEUED;
2243 }
2244 
2245 static ieee80211_rx_result debug_noinline
2246 ieee80211_rx_h_userspace_mgmt(struct ieee80211_rx_data *rx)
2247 {
2248 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
2249 
2250 	/* skip known-bad action frames and return them in the next handler */
2251 	if (status->rx_flags & IEEE80211_RX_MALFORMED_ACTION_FRM)
2252 		return RX_CONTINUE;
2253 
2254 	/*
2255 	 * Getting here means the kernel doesn't know how to handle
2256 	 * it, but maybe userspace does ... include returned frames
2257 	 * so userspace can register for those to know whether ones
2258 	 * it transmitted were processed or returned.
2259 	 */
2260 
2261 	if (cfg80211_rx_mgmt(rx->sdata->dev, status->freq,
2262 			     rx->skb->data, rx->skb->len,
2263 			     GFP_ATOMIC)) {
2264 		if (rx->sta)
2265 			rx->sta->rx_packets++;
2266 		dev_kfree_skb(rx->skb);
2267 		return RX_QUEUED;
2268 	}
2269 
2270 
2271 	return RX_CONTINUE;
2272 }
2273 
2274 static ieee80211_rx_result debug_noinline
2275 ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
2276 {
2277 	struct ieee80211_local *local = rx->local;
2278 	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
2279 	struct sk_buff *nskb;
2280 	struct ieee80211_sub_if_data *sdata = rx->sdata;
2281 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
2282 
2283 	if (!ieee80211_is_action(mgmt->frame_control))
2284 		return RX_CONTINUE;
2285 
2286 	/*
2287 	 * For AP mode, hostapd is responsible for handling any action
2288 	 * frames that we didn't handle, including returning unknown
2289 	 * ones. For all other modes we will return them to the sender,
2290 	 * setting the 0x80 bit in the action category, as required by
2291 	 * 802.11-2007 7.3.1.11.
2292 	 * Newer versions of hostapd shall also use the management frame
2293 	 * registration mechanisms, but older ones still use cooked
2294 	 * monitor interfaces so push all frames there.
2295 	 */
2296 	if (!(status->rx_flags & IEEE80211_RX_MALFORMED_ACTION_FRM) &&
2297 	    (sdata->vif.type == NL80211_IFTYPE_AP ||
2298 	     sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
2299 		return RX_DROP_MONITOR;
2300 
2301 	/* do not return rejected action frames */
2302 	if (mgmt->u.action.category & 0x80)
2303 		return RX_DROP_UNUSABLE;
2304 
2305 	nskb = skb_copy_expand(rx->skb, local->hw.extra_tx_headroom, 0,
2306 			       GFP_ATOMIC);
2307 	if (nskb) {
2308 		struct ieee80211_mgmt *nmgmt = (void *)nskb->data;
2309 
2310 		nmgmt->u.action.category |= 0x80;
2311 		memcpy(nmgmt->da, nmgmt->sa, ETH_ALEN);
2312 		memcpy(nmgmt->sa, rx->sdata->vif.addr, ETH_ALEN);
2313 
2314 		memset(nskb->cb, 0, sizeof(nskb->cb));
2315 
2316 		ieee80211_tx_skb(rx->sdata, nskb);
2317 	}
2318 	dev_kfree_skb(rx->skb);
2319 	return RX_QUEUED;
2320 }
2321 
2322 static ieee80211_rx_result debug_noinline
2323 ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
2324 {
2325 	struct ieee80211_sub_if_data *sdata = rx->sdata;
2326 	ieee80211_rx_result rxs;
2327 	struct ieee80211_mgmt *mgmt = (void *)rx->skb->data;
2328 	__le16 stype;
2329 
2330 	rxs = ieee80211_work_rx_mgmt(rx->sdata, rx->skb);
2331 	if (rxs != RX_CONTINUE)
2332 		return rxs;
2333 
2334 	stype = mgmt->frame_control & cpu_to_le16(IEEE80211_FCTL_STYPE);
2335 
2336 	if (!ieee80211_vif_is_mesh(&sdata->vif) &&
2337 	    sdata->vif.type != NL80211_IFTYPE_ADHOC &&
2338 	    sdata->vif.type != NL80211_IFTYPE_STATION)
2339 		return RX_DROP_MONITOR;
2340 
2341 	switch (stype) {
2342 	case cpu_to_le16(IEEE80211_STYPE_BEACON):
2343 	case cpu_to_le16(IEEE80211_STYPE_PROBE_RESP):
2344 		/* process for all: mesh, mlme, ibss */
2345 		break;
2346 	case cpu_to_le16(IEEE80211_STYPE_DEAUTH):
2347 	case cpu_to_le16(IEEE80211_STYPE_DISASSOC):
2348 		if (is_multicast_ether_addr(mgmt->da) &&
2349 		    !is_broadcast_ether_addr(mgmt->da))
2350 			return RX_DROP_MONITOR;
2351 
2352 		/* process only for station */
2353 		if (sdata->vif.type != NL80211_IFTYPE_STATION)
2354 			return RX_DROP_MONITOR;
2355 		break;
2356 	case cpu_to_le16(IEEE80211_STYPE_PROBE_REQ):
2357 	case cpu_to_le16(IEEE80211_STYPE_AUTH):
2358 		/* process only for ibss */
2359 		if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
2360 			return RX_DROP_MONITOR;
2361 		break;
2362 	default:
2363 		return RX_DROP_MONITOR;
2364 	}
2365 
2366 	/* queue up frame and kick off work to process it */
2367 	rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
2368 	skb_queue_tail(&sdata->skb_queue, rx->skb);
2369 	ieee80211_queue_work(&rx->local->hw, &sdata->work);
2370 	if (rx->sta)
2371 		rx->sta->rx_packets++;
2372 
2373 	return RX_QUEUED;
2374 }
2375 
2376 /* TODO: use IEEE80211_RX_FRAGMENTED */
2377 static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
2378 					struct ieee80211_rate *rate)
2379 {
2380 	struct ieee80211_sub_if_data *sdata;
2381 	struct ieee80211_local *local = rx->local;
2382 	struct ieee80211_rtap_hdr {
2383 		struct ieee80211_radiotap_header hdr;
2384 		u8 flags;
2385 		u8 rate_or_pad;
2386 		__le16 chan_freq;
2387 		__le16 chan_flags;
2388 	} __packed *rthdr;
2389 	struct sk_buff *skb = rx->skb, *skb2;
2390 	struct net_device *prev_dev = NULL;
2391 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2392 
2393 	/*
2394 	 * If cooked monitor has been processed already, then
2395 	 * don't do it again. If not, set the flag.
2396 	 */
2397 	if (rx->flags & IEEE80211_RX_CMNTR)
2398 		goto out_free_skb;
2399 	rx->flags |= IEEE80211_RX_CMNTR;
2400 
2401 	if (skb_headroom(skb) < sizeof(*rthdr) &&
2402 	    pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
2403 		goto out_free_skb;
2404 
2405 	rthdr = (void *)skb_push(skb, sizeof(*rthdr));
2406 	memset(rthdr, 0, sizeof(*rthdr));
2407 	rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
2408 	rthdr->hdr.it_present =
2409 		cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
2410 			    (1 << IEEE80211_RADIOTAP_CHANNEL));
2411 
2412 	if (rate) {
2413 		rthdr->rate_or_pad = rate->bitrate / 5;
2414 		rthdr->hdr.it_present |=
2415 			cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
2416 	}
2417 	rthdr->chan_freq = cpu_to_le16(status->freq);
2418 
2419 	if (status->band == IEEE80211_BAND_5GHZ)
2420 		rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_OFDM |
2421 						IEEE80211_CHAN_5GHZ);
2422 	else
2423 		rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_DYN |
2424 						IEEE80211_CHAN_2GHZ);
2425 
2426 	skb_set_mac_header(skb, 0);
2427 	skb->ip_summed = CHECKSUM_UNNECESSARY;
2428 	skb->pkt_type = PACKET_OTHERHOST;
2429 	skb->protocol = htons(ETH_P_802_2);
2430 
2431 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
2432 		if (!ieee80211_sdata_running(sdata))
2433 			continue;
2434 
2435 		if (sdata->vif.type != NL80211_IFTYPE_MONITOR ||
2436 		    !(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
2437 			continue;
2438 
2439 		if (prev_dev) {
2440 			skb2 = skb_clone(skb, GFP_ATOMIC);
2441 			if (skb2) {
2442 				skb2->dev = prev_dev;
2443 				netif_receive_skb(skb2);
2444 			}
2445 		}
2446 
2447 		prev_dev = sdata->dev;
2448 		sdata->dev->stats.rx_packets++;
2449 		sdata->dev->stats.rx_bytes += skb->len;
2450 	}
2451 
2452 	if (prev_dev) {
2453 		skb->dev = prev_dev;
2454 		netif_receive_skb(skb);
2455 		return;
2456 	}
2457 
2458  out_free_skb:
2459 	dev_kfree_skb(skb);
2460 }
2461 
2462 static void ieee80211_rx_handlers_result(struct ieee80211_rx_data *rx,
2463 					 ieee80211_rx_result res)
2464 {
2465 	switch (res) {
2466 	case RX_DROP_MONITOR:
2467 		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
2468 		if (rx->sta)
2469 			rx->sta->rx_dropped++;
2470 		/* fall through */
2471 	case RX_CONTINUE: {
2472 		struct ieee80211_rate *rate = NULL;
2473 		struct ieee80211_supported_band *sband;
2474 		struct ieee80211_rx_status *status;
2475 
2476 		status = IEEE80211_SKB_RXCB((rx->skb));
2477 
2478 		sband = rx->local->hw.wiphy->bands[status->band];
2479 		if (!(status->flag & RX_FLAG_HT))
2480 			rate = &sband->bitrates[status->rate_idx];
2481 
2482 		ieee80211_rx_cooked_monitor(rx, rate);
2483 		break;
2484 		}
2485 	case RX_DROP_UNUSABLE:
2486 		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
2487 		if (rx->sta)
2488 			rx->sta->rx_dropped++;
2489 		dev_kfree_skb(rx->skb);
2490 		break;
2491 	case RX_QUEUED:
2492 		I802_DEBUG_INC(rx->sdata->local->rx_handlers_queued);
2493 		break;
2494 	}
2495 }
2496 
2497 static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx)
2498 {
2499 	ieee80211_rx_result res = RX_DROP_MONITOR;
2500 	struct sk_buff *skb;
2501 
2502 #define CALL_RXH(rxh)			\
2503 	do {				\
2504 		res = rxh(rx);		\
2505 		if (res != RX_CONTINUE)	\
2506 			goto rxh_next;  \
2507 	} while (0);
2508 
2509 	spin_lock(&rx->local->rx_skb_queue.lock);
2510 	if (rx->local->running_rx_handler)
2511 		goto unlock;
2512 
2513 	rx->local->running_rx_handler = true;
2514 
2515 	while ((skb = __skb_dequeue(&rx->local->rx_skb_queue))) {
2516 		spin_unlock(&rx->local->rx_skb_queue.lock);
2517 
2518 		/*
2519 		 * all the other fields are valid across frames
2520 		 * that belong to an aMPDU since they are on the
2521 		 * same TID from the same station
2522 		 */
2523 		rx->skb = skb;
2524 
2525 		CALL_RXH(ieee80211_rx_h_decrypt)
2526 		CALL_RXH(ieee80211_rx_h_check_more_data)
2527 		CALL_RXH(ieee80211_rx_h_sta_process)
2528 		CALL_RXH(ieee80211_rx_h_defragment)
2529 		CALL_RXH(ieee80211_rx_h_ps_poll)
2530 		CALL_RXH(ieee80211_rx_h_michael_mic_verify)
2531 		/* must be after MMIC verify so header is counted in MPDU mic */
2532 		CALL_RXH(ieee80211_rx_h_remove_qos_control)
2533 		CALL_RXH(ieee80211_rx_h_amsdu)
2534 #ifdef CONFIG_MAC80211_MESH
2535 		if (ieee80211_vif_is_mesh(&rx->sdata->vif))
2536 			CALL_RXH(ieee80211_rx_h_mesh_fwding);
2537 #endif
2538 		CALL_RXH(ieee80211_rx_h_data)
2539 		CALL_RXH(ieee80211_rx_h_ctrl);
2540 		CALL_RXH(ieee80211_rx_h_mgmt_check)
2541 		CALL_RXH(ieee80211_rx_h_action)
2542 		CALL_RXH(ieee80211_rx_h_userspace_mgmt)
2543 		CALL_RXH(ieee80211_rx_h_action_return)
2544 		CALL_RXH(ieee80211_rx_h_mgmt)
2545 
2546  rxh_next:
2547 		ieee80211_rx_handlers_result(rx, res);
2548 		spin_lock(&rx->local->rx_skb_queue.lock);
2549 #undef CALL_RXH
2550 	}
2551 
2552 	rx->local->running_rx_handler = false;
2553 
2554  unlock:
2555 	spin_unlock(&rx->local->rx_skb_queue.lock);
2556 }
2557 
2558 static void ieee80211_invoke_rx_handlers(struct ieee80211_rx_data *rx)
2559 {
2560 	ieee80211_rx_result res = RX_DROP_MONITOR;
2561 
2562 #define CALL_RXH(rxh)			\
2563 	do {				\
2564 		res = rxh(rx);		\
2565 		if (res != RX_CONTINUE)	\
2566 			goto rxh_next;  \
2567 	} while (0);
2568 
2569 	CALL_RXH(ieee80211_rx_h_passive_scan)
2570 	CALL_RXH(ieee80211_rx_h_check)
2571 
2572 	ieee80211_rx_reorder_ampdu(rx);
2573 
2574 	ieee80211_rx_handlers(rx);
2575 	return;
2576 
2577  rxh_next:
2578 	ieee80211_rx_handlers_result(rx, res);
2579 
2580 #undef CALL_RXH
2581 }
2582 
2583 /*
2584  * This function makes calls into the RX path, therefore
2585  * it has to be invoked under RCU read lock.
2586  */
2587 void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid)
2588 {
2589 	struct ieee80211_rx_data rx = {
2590 		.sta = sta,
2591 		.sdata = sta->sdata,
2592 		.local = sta->local,
2593 		.queue = tid,
2594 		.flags = 0,
2595 	};
2596 	struct tid_ampdu_rx *tid_agg_rx;
2597 
2598 	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
2599 	if (!tid_agg_rx)
2600 		return;
2601 
2602 	spin_lock(&tid_agg_rx->reorder_lock);
2603 	ieee80211_sta_reorder_release(&sta->local->hw, tid_agg_rx);
2604 	spin_unlock(&tid_agg_rx->reorder_lock);
2605 
2606 	ieee80211_rx_handlers(&rx);
2607 }
2608 
2609 /* main receive path */
2610 
2611 static int prepare_for_handlers(struct ieee80211_rx_data *rx,
2612 				struct ieee80211_hdr *hdr)
2613 {
2614 	struct ieee80211_sub_if_data *sdata = rx->sdata;
2615 	struct sk_buff *skb = rx->skb;
2616 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2617 	u8 *bssid = ieee80211_get_bssid(hdr, skb->len, sdata->vif.type);
2618 	int multicast = is_multicast_ether_addr(hdr->addr1);
2619 
2620 	switch (sdata->vif.type) {
2621 	case NL80211_IFTYPE_STATION:
2622 		if (!bssid && !sdata->u.mgd.use_4addr)
2623 			return 0;
2624 		if (!multicast &&
2625 		    compare_ether_addr(sdata->vif.addr, hdr->addr1) != 0) {
2626 			if (!(sdata->dev->flags & IFF_PROMISC) ||
2627 			    sdata->u.mgd.use_4addr)
2628 				return 0;
2629 			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
2630 		}
2631 		break;
2632 	case NL80211_IFTYPE_ADHOC:
2633 		if (!bssid)
2634 			return 0;
2635 		if (ieee80211_is_beacon(hdr->frame_control)) {
2636 			return 1;
2637 		}
2638 		else if (!ieee80211_bssid_match(bssid, sdata->u.ibss.bssid)) {
2639 			if (!(status->rx_flags & IEEE80211_RX_IN_SCAN))
2640 				return 0;
2641 			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
2642 		} else if (!multicast &&
2643 			   compare_ether_addr(sdata->vif.addr,
2644 					      hdr->addr1) != 0) {
2645 			if (!(sdata->dev->flags & IFF_PROMISC))
2646 				return 0;
2647 			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
2648 		} else if (!rx->sta) {
2649 			int rate_idx;
2650 			if (status->flag & RX_FLAG_HT)
2651 				rate_idx = 0; /* TODO: HT rates */
2652 			else
2653 				rate_idx = status->rate_idx;
2654 			rx->sta = ieee80211_ibss_add_sta(sdata, bssid,
2655 					hdr->addr2, BIT(rate_idx), GFP_ATOMIC);
2656 		}
2657 		break;
2658 	case NL80211_IFTYPE_MESH_POINT:
2659 		if (!multicast &&
2660 		    compare_ether_addr(sdata->vif.addr,
2661 				       hdr->addr1) != 0) {
2662 			if (!(sdata->dev->flags & IFF_PROMISC))
2663 				return 0;
2664 
2665 			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
2666 		}
2667 		break;
2668 	case NL80211_IFTYPE_AP_VLAN:
2669 	case NL80211_IFTYPE_AP:
2670 		if (!bssid) {
2671 			if (compare_ether_addr(sdata->vif.addr,
2672 					       hdr->addr1))
2673 				return 0;
2674 		} else if (!ieee80211_bssid_match(bssid,
2675 					sdata->vif.addr)) {
2676 			if (!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
2677 			    !ieee80211_is_beacon(hdr->frame_control))
2678 				return 0;
2679 			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
2680 		}
2681 		break;
2682 	case NL80211_IFTYPE_WDS:
2683 		if (bssid || !ieee80211_is_data(hdr->frame_control))
2684 			return 0;
2685 		if (compare_ether_addr(sdata->u.wds.remote_addr, hdr->addr2))
2686 			return 0;
2687 		break;
2688 	default:
2689 		/* should never get here */
2690 		WARN_ON(1);
2691 		break;
2692 	}
2693 
2694 	return 1;
2695 }
2696 
2697 /*
2698  * This function returns whether or not the SKB
2699  * was destined for RX processing or not, which,
2700  * if consume is true, is equivalent to whether
2701  * or not the skb was consumed.
2702  */
2703 static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx,
2704 					    struct sk_buff *skb, bool consume)
2705 {
2706 	struct ieee80211_local *local = rx->local;
2707 	struct ieee80211_sub_if_data *sdata = rx->sdata;
2708 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2709 	struct ieee80211_hdr *hdr = (void *)skb->data;
2710 	int prepares;
2711 
2712 	rx->skb = skb;
2713 	status->rx_flags |= IEEE80211_RX_RA_MATCH;
2714 	prepares = prepare_for_handlers(rx, hdr);
2715 
2716 	if (!prepares)
2717 		return false;
2718 
2719 	if (!consume) {
2720 		skb = skb_copy(skb, GFP_ATOMIC);
2721 		if (!skb) {
2722 			if (net_ratelimit())
2723 				wiphy_debug(local->hw.wiphy,
2724 					"failed to copy skb for %s\n",
2725 					sdata->name);
2726 			return true;
2727 		}
2728 
2729 		rx->skb = skb;
2730 	}
2731 
2732 	ieee80211_invoke_rx_handlers(rx);
2733 	return true;
2734 }
2735 
2736 /*
2737  * This is the actual Rx frames handler. as it blongs to Rx path it must
2738  * be called with rcu_read_lock protection.
2739  */
2740 static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
2741 					 struct sk_buff *skb)
2742 {
2743 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2744 	struct ieee80211_local *local = hw_to_local(hw);
2745 	struct ieee80211_sub_if_data *sdata;
2746 	struct ieee80211_hdr *hdr;
2747 	__le16 fc;
2748 	struct ieee80211_rx_data rx;
2749 	struct ieee80211_sub_if_data *prev;
2750 	struct sta_info *sta, *tmp, *prev_sta;
2751 	int err = 0;
2752 
2753 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
2754 	memset(&rx, 0, sizeof(rx));
2755 	rx.skb = skb;
2756 	rx.local = local;
2757 
2758 	if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
2759 		local->dot11ReceivedFragmentCount++;
2760 
2761 	if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
2762 		     test_bit(SCAN_SW_SCANNING, &local->scanning)))
2763 		status->rx_flags |= IEEE80211_RX_IN_SCAN;
2764 
2765 	if (ieee80211_is_mgmt(fc))
2766 		err = skb_linearize(skb);
2767 	else
2768 		err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
2769 
2770 	if (err) {
2771 		dev_kfree_skb(skb);
2772 		return;
2773 	}
2774 
2775 	hdr = (struct ieee80211_hdr *)skb->data;
2776 	ieee80211_parse_qos(&rx);
2777 	ieee80211_verify_alignment(&rx);
2778 
2779 	if (ieee80211_is_data(fc)) {
2780 		prev_sta = NULL;
2781 
2782 		for_each_sta_info(local, hdr->addr2, sta, tmp) {
2783 			if (!prev_sta) {
2784 				prev_sta = sta;
2785 				continue;
2786 			}
2787 
2788 			rx.sta = prev_sta;
2789 			rx.sdata = prev_sta->sdata;
2790 			ieee80211_prepare_and_rx_handle(&rx, skb, false);
2791 
2792 			prev_sta = sta;
2793 		}
2794 
2795 		if (prev_sta) {
2796 			rx.sta = prev_sta;
2797 			rx.sdata = prev_sta->sdata;
2798 
2799 			if (ieee80211_prepare_and_rx_handle(&rx, skb, true))
2800 				return;
2801 			goto out;
2802 		}
2803 	}
2804 
2805 	prev = NULL;
2806 
2807 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
2808 		if (!ieee80211_sdata_running(sdata))
2809 			continue;
2810 
2811 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
2812 		    sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
2813 			continue;
2814 
2815 		/*
2816 		 * frame is destined for this interface, but if it's
2817 		 * not also for the previous one we handle that after
2818 		 * the loop to avoid copying the SKB once too much
2819 		 */
2820 
2821 		if (!prev) {
2822 			prev = sdata;
2823 			continue;
2824 		}
2825 
2826 		rx.sta = sta_info_get_bss(prev, hdr->addr2);
2827 		rx.sdata = prev;
2828 		ieee80211_prepare_and_rx_handle(&rx, skb, false);
2829 
2830 		prev = sdata;
2831 	}
2832 
2833 	if (prev) {
2834 		rx.sta = sta_info_get_bss(prev, hdr->addr2);
2835 		rx.sdata = prev;
2836 
2837 		if (ieee80211_prepare_and_rx_handle(&rx, skb, true))
2838 			return;
2839 	}
2840 
2841  out:
2842 	dev_kfree_skb(skb);
2843 }
2844 
2845 /*
2846  * This is the receive path handler. It is called by a low level driver when an
2847  * 802.11 MPDU is received from the hardware.
2848  */
2849 void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
2850 {
2851 	struct ieee80211_local *local = hw_to_local(hw);
2852 	struct ieee80211_rate *rate = NULL;
2853 	struct ieee80211_supported_band *sband;
2854 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
2855 
2856 	WARN_ON_ONCE(softirq_count() == 0);
2857 
2858 	if (WARN_ON(status->band < 0 ||
2859 		    status->band >= IEEE80211_NUM_BANDS))
2860 		goto drop;
2861 
2862 	sband = local->hw.wiphy->bands[status->band];
2863 	if (WARN_ON(!sband))
2864 		goto drop;
2865 
2866 	/*
2867 	 * If we're suspending, it is possible although not too likely
2868 	 * that we'd be receiving frames after having already partially
2869 	 * quiesced the stack. We can't process such frames then since
2870 	 * that might, for example, cause stations to be added or other
2871 	 * driver callbacks be invoked.
2872 	 */
2873 	if (unlikely(local->quiescing || local->suspended))
2874 		goto drop;
2875 
2876 	/*
2877 	 * The same happens when we're not even started,
2878 	 * but that's worth a warning.
2879 	 */
2880 	if (WARN_ON(!local->started))
2881 		goto drop;
2882 
2883 	if (likely(!(status->flag & RX_FLAG_FAILED_PLCP_CRC))) {
2884 		/*
2885 		 * Validate the rate, unless a PLCP error means that
2886 		 * we probably can't have a valid rate here anyway.
2887 		 */
2888 
2889 		if (status->flag & RX_FLAG_HT) {
2890 			/*
2891 			 * rate_idx is MCS index, which can be [0-76]
2892 			 * as documented on:
2893 			 *
2894 			 * http://wireless.kernel.org/en/developers/Documentation/ieee80211/802.11n
2895 			 *
2896 			 * Anything else would be some sort of driver or
2897 			 * hardware error. The driver should catch hardware
2898 			 * errors.
2899 			 */
2900 			if (WARN((status->rate_idx < 0 ||
2901 				 status->rate_idx > 76),
2902 				 "Rate marked as an HT rate but passed "
2903 				 "status->rate_idx is not "
2904 				 "an MCS index [0-76]: %d (0x%02x)\n",
2905 				 status->rate_idx,
2906 				 status->rate_idx))
2907 				goto drop;
2908 		} else {
2909 			if (WARN_ON(status->rate_idx < 0 ||
2910 				    status->rate_idx >= sband->n_bitrates))
2911 				goto drop;
2912 			rate = &sband->bitrates[status->rate_idx];
2913 		}
2914 	}
2915 
2916 	status->rx_flags = 0;
2917 
2918 	/*
2919 	 * key references and virtual interfaces are protected using RCU
2920 	 * and this requires that we are in a read-side RCU section during
2921 	 * receive processing
2922 	 */
2923 	rcu_read_lock();
2924 
2925 	/*
2926 	 * Frames with failed FCS/PLCP checksum are not returned,
2927 	 * all other frames are returned without radiotap header
2928 	 * if it was previously present.
2929 	 * Also, frames with less than 16 bytes are dropped.
2930 	 */
2931 	skb = ieee80211_rx_monitor(local, skb, rate);
2932 	if (!skb) {
2933 		rcu_read_unlock();
2934 		return;
2935 	}
2936 
2937 	ieee80211_tpt_led_trig_rx(local,
2938 			((struct ieee80211_hdr *)skb->data)->frame_control,
2939 			skb->len);
2940 	__ieee80211_rx_handle_packet(hw, skb);
2941 
2942 	rcu_read_unlock();
2943 
2944 	return;
2945  drop:
2946 	kfree_skb(skb);
2947 }
2948 EXPORT_SYMBOL(ieee80211_rx);
2949 
2950 /* This is a version of the rx handler that can be called from hard irq
2951  * context. Post the skb on the queue and schedule the tasklet */
2952 void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb)
2953 {
2954 	struct ieee80211_local *local = hw_to_local(hw);
2955 
2956 	BUILD_BUG_ON(sizeof(struct ieee80211_rx_status) > sizeof(skb->cb));
2957 
2958 	skb->pkt_type = IEEE80211_RX_MSG;
2959 	skb_queue_tail(&local->skb_queue, skb);
2960 	tasklet_schedule(&local->tasklet);
2961 }
2962 EXPORT_SYMBOL(ieee80211_rx_irqsafe);
2963