xref: /openbmc/linux/net/mac80211/tx.c (revision b6dcefde)
1 /*
2  * Copyright 2002-2005, Instant802 Networks, Inc.
3  * Copyright 2005-2006, Devicescape Software, Inc.
4  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
5  * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  *
12  * Transmit and frame generation functions.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/slab.h>
17 #include <linux/skbuff.h>
18 #include <linux/etherdevice.h>
19 #include <linux/bitmap.h>
20 #include <linux/rcupdate.h>
21 #include <net/net_namespace.h>
22 #include <net/ieee80211_radiotap.h>
23 #include <net/cfg80211.h>
24 #include <net/mac80211.h>
25 #include <asm/unaligned.h>
26 
27 #include "ieee80211_i.h"
28 #include "driver-ops.h"
29 #include "led.h"
30 #include "mesh.h"
31 #include "wep.h"
32 #include "wpa.h"
33 #include "wme.h"
34 #include "rate.h"
35 
36 #define IEEE80211_TX_OK		0
37 #define IEEE80211_TX_AGAIN	1
38 #define IEEE80211_TX_PENDING	2
39 
40 /* misc utils */
41 
42 static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
43 				 int next_frag_len)
44 {
45 	int rate, mrate, erp, dur, i;
46 	struct ieee80211_rate *txrate;
47 	struct ieee80211_local *local = tx->local;
48 	struct ieee80211_supported_band *sband;
49 	struct ieee80211_hdr *hdr;
50 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
51 
52 	/* assume HW handles this */
53 	if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
54 		return 0;
55 
56 	/* uh huh? */
57 	if (WARN_ON_ONCE(info->control.rates[0].idx < 0))
58 		return 0;
59 
60 	sband = local->hw.wiphy->bands[tx->channel->band];
61 	txrate = &sband->bitrates[info->control.rates[0].idx];
62 
63 	erp = txrate->flags & IEEE80211_RATE_ERP_G;
64 
65 	/*
66 	 * data and mgmt (except PS Poll):
67 	 * - during CFP: 32768
68 	 * - during contention period:
69 	 *   if addr1 is group address: 0
70 	 *   if more fragments = 0 and addr1 is individual address: time to
71 	 *      transmit one ACK plus SIFS
72 	 *   if more fragments = 1 and addr1 is individual address: time to
73 	 *      transmit next fragment plus 2 x ACK plus 3 x SIFS
74 	 *
75 	 * IEEE 802.11, 9.6:
76 	 * - control response frame (CTS or ACK) shall be transmitted using the
77 	 *   same rate as the immediately previous frame in the frame exchange
78 	 *   sequence, if this rate belongs to the PHY mandatory rates, or else
79 	 *   at the highest possible rate belonging to the PHY rates in the
80 	 *   BSSBasicRateSet
81 	 */
82 	hdr = (struct ieee80211_hdr *)tx->skb->data;
83 	if (ieee80211_is_ctl(hdr->frame_control)) {
84 		/* TODO: These control frames are not currently sent by
85 		 * mac80211, but should they be implemented, this function
86 		 * needs to be updated to support duration field calculation.
87 		 *
88 		 * RTS: time needed to transmit pending data/mgmt frame plus
89 		 *    one CTS frame plus one ACK frame plus 3 x SIFS
90 		 * CTS: duration of immediately previous RTS minus time
91 		 *    required to transmit CTS and its SIFS
92 		 * ACK: 0 if immediately previous directed data/mgmt had
93 		 *    more=0, with more=1 duration in ACK frame is duration
94 		 *    from previous frame minus time needed to transmit ACK
95 		 *    and its SIFS
96 		 * PS Poll: BIT(15) | BIT(14) | aid
97 		 */
98 		return 0;
99 	}
100 
101 	/* data/mgmt */
102 	if (0 /* FIX: data/mgmt during CFP */)
103 		return cpu_to_le16(32768);
104 
105 	if (group_addr) /* Group address as the destination - no ACK */
106 		return 0;
107 
108 	/* Individual destination address:
109 	 * IEEE 802.11, Ch. 9.6 (after IEEE 802.11g changes)
110 	 * CTS and ACK frames shall be transmitted using the highest rate in
111 	 * basic rate set that is less than or equal to the rate of the
112 	 * immediately previous frame and that is using the same modulation
113 	 * (CCK or OFDM). If no basic rate set matches with these requirements,
114 	 * the highest mandatory rate of the PHY that is less than or equal to
115 	 * the rate of the previous frame is used.
116 	 * Mandatory rates for IEEE 802.11g PHY: 1, 2, 5.5, 11, 6, 12, 24 Mbps
117 	 */
118 	rate = -1;
119 	/* use lowest available if everything fails */
120 	mrate = sband->bitrates[0].bitrate;
121 	for (i = 0; i < sband->n_bitrates; i++) {
122 		struct ieee80211_rate *r = &sband->bitrates[i];
123 
124 		if (r->bitrate > txrate->bitrate)
125 			break;
126 
127 		if (tx->sdata->vif.bss_conf.basic_rates & BIT(i))
128 			rate = r->bitrate;
129 
130 		switch (sband->band) {
131 		case IEEE80211_BAND_2GHZ: {
132 			u32 flag;
133 			if (tx->sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
134 				flag = IEEE80211_RATE_MANDATORY_G;
135 			else
136 				flag = IEEE80211_RATE_MANDATORY_B;
137 			if (r->flags & flag)
138 				mrate = r->bitrate;
139 			break;
140 		}
141 		case IEEE80211_BAND_5GHZ:
142 			if (r->flags & IEEE80211_RATE_MANDATORY_A)
143 				mrate = r->bitrate;
144 			break;
145 		case IEEE80211_NUM_BANDS:
146 			WARN_ON(1);
147 			break;
148 		}
149 	}
150 	if (rate == -1) {
151 		/* No matching basic rate found; use highest suitable mandatory
152 		 * PHY rate */
153 		rate = mrate;
154 	}
155 
156 	/* Time needed to transmit ACK
157 	 * (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up
158 	 * to closest integer */
159 
160 	dur = ieee80211_frame_duration(local, 10, rate, erp,
161 				tx->sdata->vif.bss_conf.use_short_preamble);
162 
163 	if (next_frag_len) {
164 		/* Frame is fragmented: duration increases with time needed to
165 		 * transmit next fragment plus ACK and 2 x SIFS. */
166 		dur *= 2; /* ACK + SIFS */
167 		/* next fragment */
168 		dur += ieee80211_frame_duration(local, next_frag_len,
169 				txrate->bitrate, erp,
170 				tx->sdata->vif.bss_conf.use_short_preamble);
171 	}
172 
173 	return cpu_to_le16(dur);
174 }
175 
176 static int inline is_ieee80211_device(struct ieee80211_local *local,
177 				      struct net_device *dev)
178 {
179 	return local == wdev_priv(dev->ieee80211_ptr);
180 }
181 
182 /* tx handlers */
183 
184 static ieee80211_tx_result debug_noinline
185 ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
186 {
187 
188 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
189 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
190 	u32 sta_flags;
191 
192 	if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED))
193 		return TX_CONTINUE;
194 
195 	if (unlikely(test_bit(SCAN_OFF_CHANNEL, &tx->local->scanning)) &&
196 	    !ieee80211_is_probe_req(hdr->frame_control) &&
197 	    !ieee80211_is_nullfunc(hdr->frame_control))
198 		/*
199 		 * When software scanning only nullfunc frames (to notify
200 		 * the sleep state to the AP) and probe requests (for the
201 		 * active scan) are allowed, all other frames should not be
202 		 * sent and we should not get here, but if we do
203 		 * nonetheless, drop them to avoid sending them
204 		 * off-channel. See the link below and
205 		 * ieee80211_start_scan() for more.
206 		 *
207 		 * http://article.gmane.org/gmane.linux.kernel.wireless.general/30089
208 		 */
209 		return TX_DROP;
210 
211 	if (tx->sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
212 		return TX_CONTINUE;
213 
214 	if (tx->flags & IEEE80211_TX_PS_BUFFERED)
215 		return TX_CONTINUE;
216 
217 	sta_flags = tx->sta ? get_sta_flags(tx->sta) : 0;
218 
219 	if (likely(tx->flags & IEEE80211_TX_UNICAST)) {
220 		if (unlikely(!(sta_flags & WLAN_STA_ASSOC) &&
221 			     tx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
222 			     ieee80211_is_data(hdr->frame_control))) {
223 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
224 			printk(KERN_DEBUG "%s: dropped data frame to not "
225 			       "associated station %pM\n",
226 			       tx->dev->name, hdr->addr1);
227 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
228 			I802_DEBUG_INC(tx->local->tx_handlers_drop_not_assoc);
229 			return TX_DROP;
230 		}
231 	} else {
232 		if (unlikely(ieee80211_is_data(hdr->frame_control) &&
233 			     tx->local->num_sta == 0 &&
234 			     tx->sdata->vif.type != NL80211_IFTYPE_ADHOC)) {
235 			/*
236 			 * No associated STAs - no need to send multicast
237 			 * frames.
238 			 */
239 			return TX_DROP;
240 		}
241 		return TX_CONTINUE;
242 	}
243 
244 	return TX_CONTINUE;
245 }
246 
247 /* This function is called whenever the AP is about to exceed the maximum limit
248  * of buffered frames for power saving STAs. This situation should not really
249  * happen often during normal operation, so dropping the oldest buffered packet
250  * from each queue should be OK to make some room for new frames. */
251 static void purge_old_ps_buffers(struct ieee80211_local *local)
252 {
253 	int total = 0, purged = 0;
254 	struct sk_buff *skb;
255 	struct ieee80211_sub_if_data *sdata;
256 	struct sta_info *sta;
257 
258 	/*
259 	 * virtual interfaces are protected by RCU
260 	 */
261 	rcu_read_lock();
262 
263 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
264 		struct ieee80211_if_ap *ap;
265 		if (sdata->vif.type != NL80211_IFTYPE_AP)
266 			continue;
267 		ap = &sdata->u.ap;
268 		skb = skb_dequeue(&ap->ps_bc_buf);
269 		if (skb) {
270 			purged++;
271 			dev_kfree_skb(skb);
272 		}
273 		total += skb_queue_len(&ap->ps_bc_buf);
274 	}
275 
276 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
277 		skb = skb_dequeue(&sta->ps_tx_buf);
278 		if (skb) {
279 			purged++;
280 			dev_kfree_skb(skb);
281 		}
282 		total += skb_queue_len(&sta->ps_tx_buf);
283 	}
284 
285 	rcu_read_unlock();
286 
287 	local->total_ps_buffered = total;
288 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
289 	printk(KERN_DEBUG "%s: PS buffers full - purged %d frames\n",
290 	       wiphy_name(local->hw.wiphy), purged);
291 #endif
292 }
293 
294 static ieee80211_tx_result
295 ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
296 {
297 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
298 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
299 
300 	/*
301 	 * broadcast/multicast frame
302 	 *
303 	 * If any of the associated stations is in power save mode,
304 	 * the frame is buffered to be sent after DTIM beacon frame.
305 	 * This is done either by the hardware or us.
306 	 */
307 
308 	/* powersaving STAs only in AP/VLAN mode */
309 	if (!tx->sdata->bss)
310 		return TX_CONTINUE;
311 
312 	/* no buffering for ordered frames */
313 	if (ieee80211_has_order(hdr->frame_control))
314 		return TX_CONTINUE;
315 
316 	/* no stations in PS mode */
317 	if (!atomic_read(&tx->sdata->bss->num_sta_ps))
318 		return TX_CONTINUE;
319 
320 	info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;
321 
322 	/* device releases frame after DTIM beacon */
323 	if (!(tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING))
324 		return TX_CONTINUE;
325 
326 	/* buffered in mac80211 */
327 	if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
328 		purge_old_ps_buffers(tx->local);
329 
330 	if (skb_queue_len(&tx->sdata->bss->ps_bc_buf) >= AP_MAX_BC_BUFFER) {
331 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
332 		if (net_ratelimit())
333 			printk(KERN_DEBUG "%s: BC TX buffer full - dropping the oldest frame\n",
334 			       tx->dev->name);
335 #endif
336 		dev_kfree_skb(skb_dequeue(&tx->sdata->bss->ps_bc_buf));
337 	} else
338 		tx->local->total_ps_buffered++;
339 
340 	skb_queue_tail(&tx->sdata->bss->ps_bc_buf, tx->skb);
341 
342 	return TX_QUEUED;
343 }
344 
345 static int ieee80211_use_mfp(__le16 fc, struct sta_info *sta,
346 			     struct sk_buff *skb)
347 {
348 	if (!ieee80211_is_mgmt(fc))
349 		return 0;
350 
351 	if (sta == NULL || !test_sta_flags(sta, WLAN_STA_MFP))
352 		return 0;
353 
354 	if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *)
355 					    skb->data))
356 		return 0;
357 
358 	return 1;
359 }
360 
361 static ieee80211_tx_result
362 ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
363 {
364 	struct sta_info *sta = tx->sta;
365 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
366 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
367 	u32 staflags;
368 
369 	if (unlikely(!sta ||
370 		     ieee80211_is_probe_resp(hdr->frame_control) ||
371 		     ieee80211_is_auth(hdr->frame_control) ||
372 		     ieee80211_is_assoc_resp(hdr->frame_control) ||
373 		     ieee80211_is_reassoc_resp(hdr->frame_control)))
374 		return TX_CONTINUE;
375 
376 	staflags = get_sta_flags(sta);
377 
378 	if (unlikely((staflags & (WLAN_STA_PS_STA | WLAN_STA_PS_DRIVER)) &&
379 		     !(info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE))) {
380 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
381 		printk(KERN_DEBUG "STA %pM aid %d: PS buffer (entries "
382 		       "before %d)\n",
383 		       sta->sta.addr, sta->sta.aid,
384 		       skb_queue_len(&sta->ps_tx_buf));
385 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
386 		if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
387 			purge_old_ps_buffers(tx->local);
388 		if (skb_queue_len(&sta->ps_tx_buf) >= STA_MAX_TX_BUFFER) {
389 			struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf);
390 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
391 			if (net_ratelimit()) {
392 				printk(KERN_DEBUG "%s: STA %pM TX "
393 				       "buffer full - dropping oldest frame\n",
394 				       tx->dev->name, sta->sta.addr);
395 			}
396 #endif
397 			dev_kfree_skb(old);
398 		} else
399 			tx->local->total_ps_buffered++;
400 
401 		/*
402 		 * Queue frame to be sent after STA wakes up/polls,
403 		 * but don't set the TIM bit if the driver is blocking
404 		 * wakeup or poll response transmissions anyway.
405 		 */
406 		if (skb_queue_empty(&sta->ps_tx_buf) &&
407 		    !(staflags & WLAN_STA_PS_DRIVER))
408 			sta_info_set_tim_bit(sta);
409 
410 		info->control.jiffies = jiffies;
411 		info->control.vif = &tx->sdata->vif;
412 		info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
413 		skb_queue_tail(&sta->ps_tx_buf, tx->skb);
414 		return TX_QUEUED;
415 	}
416 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
417 	else if (unlikely(staflags & WLAN_STA_PS_STA)) {
418 		printk(KERN_DEBUG "%s: STA %pM in PS mode, but pspoll "
419 		       "set -> send frame\n", tx->dev->name,
420 		       sta->sta.addr);
421 	}
422 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
423 
424 	return TX_CONTINUE;
425 }
426 
427 static ieee80211_tx_result debug_noinline
428 ieee80211_tx_h_ps_buf(struct ieee80211_tx_data *tx)
429 {
430 	if (unlikely(tx->flags & IEEE80211_TX_PS_BUFFERED))
431 		return TX_CONTINUE;
432 
433 	if (tx->flags & IEEE80211_TX_UNICAST)
434 		return ieee80211_tx_h_unicast_ps_buf(tx);
435 	else
436 		return ieee80211_tx_h_multicast_ps_buf(tx);
437 }
438 
439 static ieee80211_tx_result debug_noinline
440 ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
441 {
442 	struct ieee80211_key *key = NULL;
443 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
444 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
445 
446 	if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT))
447 		tx->key = NULL;
448 	else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
449 		tx->key = key;
450 	else if (ieee80211_is_mgmt(hdr->frame_control) &&
451 		 (key = rcu_dereference(tx->sdata->default_mgmt_key)))
452 		tx->key = key;
453 	else if ((key = rcu_dereference(tx->sdata->default_key)))
454 		tx->key = key;
455 	else if (tx->sdata->drop_unencrypted &&
456 		 (tx->skb->protocol != cpu_to_be16(ETH_P_PAE)) &&
457 		 !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
458 		 (!ieee80211_is_robust_mgmt_frame(hdr) ||
459 		  (ieee80211_is_action(hdr->frame_control) &&
460 		   tx->sta && test_sta_flags(tx->sta, WLAN_STA_MFP)))) {
461 		I802_DEBUG_INC(tx->local->tx_handlers_drop_unencrypted);
462 		return TX_DROP;
463 	} else
464 		tx->key = NULL;
465 
466 	if (tx->key) {
467 		tx->key->tx_rx_count++;
468 		/* TODO: add threshold stuff again */
469 
470 		switch (tx->key->conf.alg) {
471 		case ALG_WEP:
472 			if (ieee80211_is_auth(hdr->frame_control))
473 				break;
474 		case ALG_TKIP:
475 			if (!ieee80211_is_data_present(hdr->frame_control))
476 				tx->key = NULL;
477 			break;
478 		case ALG_CCMP:
479 			if (!ieee80211_is_data_present(hdr->frame_control) &&
480 			    !ieee80211_use_mfp(hdr->frame_control, tx->sta,
481 					       tx->skb))
482 				tx->key = NULL;
483 			break;
484 		case ALG_AES_CMAC:
485 			if (!ieee80211_is_mgmt(hdr->frame_control))
486 				tx->key = NULL;
487 			break;
488 		}
489 	}
490 
491 	if (!tx->key || !(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
492 		info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
493 
494 	return TX_CONTINUE;
495 }
496 
497 static ieee80211_tx_result debug_noinline
498 ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
499 {
500 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
501 	struct ieee80211_hdr *hdr = (void *)tx->skb->data;
502 	struct ieee80211_supported_band *sband;
503 	struct ieee80211_rate *rate;
504 	int i, len;
505 	bool inval = false, rts = false, short_preamble = false;
506 	struct ieee80211_tx_rate_control txrc;
507 	u32 sta_flags;
508 
509 	memset(&txrc, 0, sizeof(txrc));
510 
511 	sband = tx->local->hw.wiphy->bands[tx->channel->band];
512 
513 	len = min_t(int, tx->skb->len + FCS_LEN,
514 			 tx->local->hw.wiphy->frag_threshold);
515 
516 	/* set up the tx rate control struct we give the RC algo */
517 	txrc.hw = local_to_hw(tx->local);
518 	txrc.sband = sband;
519 	txrc.bss_conf = &tx->sdata->vif.bss_conf;
520 	txrc.skb = tx->skb;
521 	txrc.reported_rate.idx = -1;
522 	txrc.max_rate_idx = tx->sdata->max_ratectrl_rateidx;
523 
524 	/* set up RTS protection if desired */
525 	if (len > tx->local->hw.wiphy->rts_threshold) {
526 		txrc.rts = rts = true;
527 	}
528 
529 	/*
530 	 * Use short preamble if the BSS can handle it, but not for
531 	 * management frames unless we know the receiver can handle
532 	 * that -- the management frame might be to a station that
533 	 * just wants a probe response.
534 	 */
535 	if (tx->sdata->vif.bss_conf.use_short_preamble &&
536 	    (ieee80211_is_data(hdr->frame_control) ||
537 	     (tx->sta && test_sta_flags(tx->sta, WLAN_STA_SHORT_PREAMBLE))))
538 		txrc.short_preamble = short_preamble = true;
539 
540 	sta_flags = tx->sta ? get_sta_flags(tx->sta) : 0;
541 
542 	/*
543 	 * Lets not bother rate control if we're associated and cannot
544 	 * talk to the sta. This should not happen.
545 	 */
546 	if (WARN(test_bit(SCAN_SW_SCANNING, &tx->local->scanning) &&
547 		 (sta_flags & WLAN_STA_ASSOC) &&
548 		 !rate_usable_index_exists(sband, &tx->sta->sta),
549 		 "%s: Dropped data frame as no usable bitrate found while "
550 		 "scanning and associated. Target station: "
551 		 "%pM on %d GHz band\n",
552 		 tx->dev->name, hdr->addr1,
553 		 tx->channel->band ? 5 : 2))
554 		return TX_DROP;
555 
556 	/*
557 	 * If we're associated with the sta at this point we know we can at
558 	 * least send the frame at the lowest bit rate.
559 	 */
560 	rate_control_get_rate(tx->sdata, tx->sta, &txrc);
561 
562 	if (unlikely(info->control.rates[0].idx < 0))
563 		return TX_DROP;
564 
565 	if (txrc.reported_rate.idx < 0)
566 		txrc.reported_rate = info->control.rates[0];
567 
568 	if (tx->sta)
569 		tx->sta->last_tx_rate = txrc.reported_rate;
570 
571 	if (unlikely(!info->control.rates[0].count))
572 		info->control.rates[0].count = 1;
573 
574 	if (WARN_ON_ONCE((info->control.rates[0].count > 1) &&
575 			 (info->flags & IEEE80211_TX_CTL_NO_ACK)))
576 		info->control.rates[0].count = 1;
577 
578 	if (is_multicast_ether_addr(hdr->addr1)) {
579 		/*
580 		 * XXX: verify the rate is in the basic rateset
581 		 */
582 		return TX_CONTINUE;
583 	}
584 
585 	/*
586 	 * set up the RTS/CTS rate as the fastest basic rate
587 	 * that is not faster than the data rate
588 	 *
589 	 * XXX: Should this check all retry rates?
590 	 */
591 	if (!(info->control.rates[0].flags & IEEE80211_TX_RC_MCS)) {
592 		s8 baserate = 0;
593 
594 		rate = &sband->bitrates[info->control.rates[0].idx];
595 
596 		for (i = 0; i < sband->n_bitrates; i++) {
597 			/* must be a basic rate */
598 			if (!(tx->sdata->vif.bss_conf.basic_rates & BIT(i)))
599 				continue;
600 			/* must not be faster than the data rate */
601 			if (sband->bitrates[i].bitrate > rate->bitrate)
602 				continue;
603 			/* maximum */
604 			if (sband->bitrates[baserate].bitrate <
605 			     sband->bitrates[i].bitrate)
606 				baserate = i;
607 		}
608 
609 		info->control.rts_cts_rate_idx = baserate;
610 	}
611 
612 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
613 		/*
614 		 * make sure there's no valid rate following
615 		 * an invalid one, just in case drivers don't
616 		 * take the API seriously to stop at -1.
617 		 */
618 		if (inval) {
619 			info->control.rates[i].idx = -1;
620 			continue;
621 		}
622 		if (info->control.rates[i].idx < 0) {
623 			inval = true;
624 			continue;
625 		}
626 
627 		/*
628 		 * For now assume MCS is already set up correctly, this
629 		 * needs to be fixed.
630 		 */
631 		if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS) {
632 			WARN_ON(info->control.rates[i].idx > 76);
633 			continue;
634 		}
635 
636 		/* set up RTS protection if desired */
637 		if (rts)
638 			info->control.rates[i].flags |=
639 				IEEE80211_TX_RC_USE_RTS_CTS;
640 
641 		/* RC is busted */
642 		if (WARN_ON_ONCE(info->control.rates[i].idx >=
643 				 sband->n_bitrates)) {
644 			info->control.rates[i].idx = -1;
645 			continue;
646 		}
647 
648 		rate = &sband->bitrates[info->control.rates[i].idx];
649 
650 		/* set up short preamble */
651 		if (short_preamble &&
652 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
653 			info->control.rates[i].flags |=
654 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
655 
656 		/* set up G protection */
657 		if (!rts && tx->sdata->vif.bss_conf.use_cts_prot &&
658 		    rate->flags & IEEE80211_RATE_ERP_G)
659 			info->control.rates[i].flags |=
660 				IEEE80211_TX_RC_USE_CTS_PROTECT;
661 	}
662 
663 	return TX_CONTINUE;
664 }
665 
666 static ieee80211_tx_result debug_noinline
667 ieee80211_tx_h_misc(struct ieee80211_tx_data *tx)
668 {
669 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
670 
671 	if (tx->sta)
672 		info->control.sta = &tx->sta->sta;
673 
674 	return TX_CONTINUE;
675 }
676 
677 static ieee80211_tx_result debug_noinline
678 ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
679 {
680 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
681 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
682 	u16 *seq;
683 	u8 *qc;
684 	int tid;
685 
686 	/*
687 	 * Packet injection may want to control the sequence
688 	 * number, if we have no matching interface then we
689 	 * neither assign one ourselves nor ask the driver to.
690 	 */
691 	if (unlikely(info->control.vif->type == NL80211_IFTYPE_MONITOR))
692 		return TX_CONTINUE;
693 
694 	if (unlikely(ieee80211_is_ctl(hdr->frame_control)))
695 		return TX_CONTINUE;
696 
697 	if (ieee80211_hdrlen(hdr->frame_control) < 24)
698 		return TX_CONTINUE;
699 
700 	/*
701 	 * Anything but QoS data that has a sequence number field
702 	 * (is long enough) gets a sequence number from the global
703 	 * counter.
704 	 */
705 	if (!ieee80211_is_data_qos(hdr->frame_control)) {
706 		/* driver should assign sequence number */
707 		info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
708 		/* for pure STA mode without beacons, we can do it */
709 		hdr->seq_ctrl = cpu_to_le16(tx->sdata->sequence_number);
710 		tx->sdata->sequence_number += 0x10;
711 		return TX_CONTINUE;
712 	}
713 
714 	/*
715 	 * This should be true for injected/management frames only, for
716 	 * management frames we have set the IEEE80211_TX_CTL_ASSIGN_SEQ
717 	 * above since they are not QoS-data frames.
718 	 */
719 	if (!tx->sta)
720 		return TX_CONTINUE;
721 
722 	/* include per-STA, per-TID sequence counter */
723 
724 	qc = ieee80211_get_qos_ctl(hdr);
725 	tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
726 	seq = &tx->sta->tid_seq[tid];
727 
728 	hdr->seq_ctrl = cpu_to_le16(*seq);
729 
730 	/* Increase the sequence number. */
731 	*seq = (*seq + 0x10) & IEEE80211_SCTL_SEQ;
732 
733 	return TX_CONTINUE;
734 }
735 
736 static int ieee80211_fragment(struct ieee80211_local *local,
737 			      struct sk_buff *skb, int hdrlen,
738 			      int frag_threshold)
739 {
740 	struct sk_buff *tail = skb, *tmp;
741 	int per_fragm = frag_threshold - hdrlen - FCS_LEN;
742 	int pos = hdrlen + per_fragm;
743 	int rem = skb->len - hdrlen - per_fragm;
744 
745 	if (WARN_ON(rem < 0))
746 		return -EINVAL;
747 
748 	while (rem) {
749 		int fraglen = per_fragm;
750 
751 		if (fraglen > rem)
752 			fraglen = rem;
753 		rem -= fraglen;
754 		tmp = dev_alloc_skb(local->tx_headroom +
755 				    frag_threshold +
756 				    IEEE80211_ENCRYPT_HEADROOM +
757 				    IEEE80211_ENCRYPT_TAILROOM);
758 		if (!tmp)
759 			return -ENOMEM;
760 		tail->next = tmp;
761 		tail = tmp;
762 		skb_reserve(tmp, local->tx_headroom +
763 				 IEEE80211_ENCRYPT_HEADROOM);
764 		/* copy control information */
765 		memcpy(tmp->cb, skb->cb, sizeof(tmp->cb));
766 		skb_copy_queue_mapping(tmp, skb);
767 		tmp->priority = skb->priority;
768 		tmp->dev = skb->dev;
769 
770 		/* copy header and data */
771 		memcpy(skb_put(tmp, hdrlen), skb->data, hdrlen);
772 		memcpy(skb_put(tmp, fraglen), skb->data + pos, fraglen);
773 
774 		pos += fraglen;
775 	}
776 
777 	skb->len = hdrlen + per_fragm;
778 	return 0;
779 }
780 
781 static ieee80211_tx_result debug_noinline
782 ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
783 {
784 	struct sk_buff *skb = tx->skb;
785 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
786 	struct ieee80211_hdr *hdr = (void *)skb->data;
787 	int frag_threshold = tx->local->hw.wiphy->frag_threshold;
788 	int hdrlen;
789 	int fragnum;
790 
791 	if (!(tx->flags & IEEE80211_TX_FRAGMENTED))
792 		return TX_CONTINUE;
793 
794 	/*
795 	 * Warn when submitting a fragmented A-MPDU frame and drop it.
796 	 * This scenario is handled in ieee80211_tx_prepare but extra
797 	 * caution taken here as fragmented ampdu may cause Tx stop.
798 	 */
799 	if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
800 		return TX_DROP;
801 
802 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
803 
804 	/* internal error, why is TX_FRAGMENTED set? */
805 	if (WARN_ON(skb->len + FCS_LEN <= frag_threshold))
806 		return TX_DROP;
807 
808 	/*
809 	 * Now fragment the frame. This will allocate all the fragments and
810 	 * chain them (using skb as the first fragment) to skb->next.
811 	 * During transmission, we will remove the successfully transmitted
812 	 * fragments from this list. When the low-level driver rejects one
813 	 * of the fragments then we will simply pretend to accept the skb
814 	 * but store it away as pending.
815 	 */
816 	if (ieee80211_fragment(tx->local, skb, hdrlen, frag_threshold))
817 		return TX_DROP;
818 
819 	/* update duration/seq/flags of fragments */
820 	fragnum = 0;
821 	do {
822 		int next_len;
823 		const __le16 morefrags = cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
824 
825 		hdr = (void *)skb->data;
826 		info = IEEE80211_SKB_CB(skb);
827 
828 		if (skb->next) {
829 			hdr->frame_control |= morefrags;
830 			next_len = skb->next->len;
831 			/*
832 			 * No multi-rate retries for fragmented frames, that
833 			 * would completely throw off the NAV at other STAs.
834 			 */
835 			info->control.rates[1].idx = -1;
836 			info->control.rates[2].idx = -1;
837 			info->control.rates[3].idx = -1;
838 			info->control.rates[4].idx = -1;
839 			BUILD_BUG_ON(IEEE80211_TX_MAX_RATES != 5);
840 			info->flags &= ~IEEE80211_TX_CTL_RATE_CTRL_PROBE;
841 		} else {
842 			hdr->frame_control &= ~morefrags;
843 			next_len = 0;
844 		}
845 		hdr->duration_id = ieee80211_duration(tx, 0, next_len);
846 		hdr->seq_ctrl |= cpu_to_le16(fragnum & IEEE80211_SCTL_FRAG);
847 		fragnum++;
848 	} while ((skb = skb->next));
849 
850 	return TX_CONTINUE;
851 }
852 
853 static ieee80211_tx_result debug_noinline
854 ieee80211_tx_h_stats(struct ieee80211_tx_data *tx)
855 {
856 	struct sk_buff *skb = tx->skb;
857 
858 	if (!tx->sta)
859 		return TX_CONTINUE;
860 
861 	tx->sta->tx_packets++;
862 	do {
863 		tx->sta->tx_fragments++;
864 		tx->sta->tx_bytes += skb->len;
865 	} while ((skb = skb->next));
866 
867 	return TX_CONTINUE;
868 }
869 
870 static ieee80211_tx_result debug_noinline
871 ieee80211_tx_h_encrypt(struct ieee80211_tx_data *tx)
872 {
873 	if (!tx->key)
874 		return TX_CONTINUE;
875 
876 	switch (tx->key->conf.alg) {
877 	case ALG_WEP:
878 		return ieee80211_crypto_wep_encrypt(tx);
879 	case ALG_TKIP:
880 		return ieee80211_crypto_tkip_encrypt(tx);
881 	case ALG_CCMP:
882 		return ieee80211_crypto_ccmp_encrypt(tx);
883 	case ALG_AES_CMAC:
884 		return ieee80211_crypto_aes_cmac_encrypt(tx);
885 	}
886 
887 	/* not reached */
888 	WARN_ON(1);
889 	return TX_DROP;
890 }
891 
892 static ieee80211_tx_result debug_noinline
893 ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx)
894 {
895 	struct sk_buff *skb = tx->skb;
896 	struct ieee80211_hdr *hdr;
897 	int next_len;
898 	bool group_addr;
899 
900 	do {
901 		hdr = (void *) skb->data;
902 		if (unlikely(ieee80211_is_pspoll(hdr->frame_control)))
903 			break; /* must not overwrite AID */
904 		next_len = skb->next ? skb->next->len : 0;
905 		group_addr = is_multicast_ether_addr(hdr->addr1);
906 
907 		hdr->duration_id =
908 			ieee80211_duration(tx, group_addr, next_len);
909 	} while ((skb = skb->next));
910 
911 	return TX_CONTINUE;
912 }
913 
914 /* actual transmit path */
915 
916 /*
917  * deal with packet injection down monitor interface
918  * with Radiotap Header -- only called for monitor mode interface
919  */
920 static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
921 					  struct sk_buff *skb)
922 {
923 	/*
924 	 * this is the moment to interpret and discard the radiotap header that
925 	 * must be at the start of the packet injected in Monitor mode
926 	 *
927 	 * Need to take some care with endian-ness since radiotap
928 	 * args are little-endian
929 	 */
930 
931 	struct ieee80211_radiotap_iterator iterator;
932 	struct ieee80211_radiotap_header *rthdr =
933 		(struct ieee80211_radiotap_header *) skb->data;
934 	struct ieee80211_supported_band *sband;
935 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
936 	int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
937 
938 	sband = tx->local->hw.wiphy->bands[tx->channel->band];
939 
940 	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
941 	tx->flags &= ~IEEE80211_TX_FRAGMENTED;
942 
943 	/*
944 	 * for every radiotap entry that is present
945 	 * (ieee80211_radiotap_iterator_next returns -ENOENT when no more
946 	 * entries present, or -EINVAL on error)
947 	 */
948 
949 	while (!ret) {
950 		ret = ieee80211_radiotap_iterator_next(&iterator);
951 
952 		if (ret)
953 			continue;
954 
955 		/* see if this argument is something we can use */
956 		switch (iterator.this_arg_index) {
957 		/*
958 		 * You must take care when dereferencing iterator.this_arg
959 		 * for multibyte types... the pointer is not aligned.  Use
960 		 * get_unaligned((type *)iterator.this_arg) to dereference
961 		 * iterator.this_arg for type "type" safely on all arches.
962 		*/
963 		case IEEE80211_RADIOTAP_FLAGS:
964 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
965 				/*
966 				 * this indicates that the skb we have been
967 				 * handed has the 32-bit FCS CRC at the end...
968 				 * we should react to that by snipping it off
969 				 * because it will be recomputed and added
970 				 * on transmission
971 				 */
972 				if (skb->len < (iterator.max_length + FCS_LEN))
973 					return false;
974 
975 				skb_trim(skb, skb->len - FCS_LEN);
976 			}
977 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
978 				info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT;
979 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
980 				tx->flags |= IEEE80211_TX_FRAGMENTED;
981 			break;
982 
983 		/*
984 		 * Please update the file
985 		 * Documentation/networking/mac80211-injection.txt
986 		 * when parsing new fields here.
987 		 */
988 
989 		default:
990 			break;
991 		}
992 	}
993 
994 	if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
995 		return false;
996 
997 	/*
998 	 * remove the radiotap header
999 	 * iterator->max_length was sanity-checked against
1000 	 * skb->len by iterator init
1001 	 */
1002 	skb_pull(skb, iterator.max_length);
1003 
1004 	return true;
1005 }
1006 
1007 /*
1008  * initialises @tx
1009  */
1010 static ieee80211_tx_result
1011 ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
1012 		     struct ieee80211_tx_data *tx,
1013 		     struct sk_buff *skb)
1014 {
1015 	struct ieee80211_local *local = sdata->local;
1016 	struct ieee80211_hdr *hdr;
1017 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1018 	int hdrlen, tid;
1019 	u8 *qc, *state;
1020 	bool queued = false;
1021 
1022 	memset(tx, 0, sizeof(*tx));
1023 	tx->skb = skb;
1024 	tx->dev = sdata->dev; /* use original interface */
1025 	tx->local = local;
1026 	tx->sdata = sdata;
1027 	tx->channel = local->hw.conf.channel;
1028 	/*
1029 	 * Set this flag (used below to indicate "automatic fragmentation"),
1030 	 * it will be cleared/left by radiotap as desired.
1031 	 */
1032 	tx->flags |= IEEE80211_TX_FRAGMENTED;
1033 
1034 	/* process and remove the injection radiotap header */
1035 	if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED)) {
1036 		if (!__ieee80211_parse_tx_radiotap(tx, skb))
1037 			return TX_DROP;
1038 
1039 		/*
1040 		 * __ieee80211_parse_tx_radiotap has now removed
1041 		 * the radiotap header that was present and pre-filled
1042 		 * 'tx' with tx control information.
1043 		 */
1044 	}
1045 
1046 	/*
1047 	 * If this flag is set to true anywhere, and we get here,
1048 	 * we are doing the needed processing, so remove the flag
1049 	 * now.
1050 	 */
1051 	info->flags &= ~IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1052 
1053 	hdr = (struct ieee80211_hdr *) skb->data;
1054 
1055 	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
1056 		tx->sta = rcu_dereference(sdata->u.vlan.sta);
1057 	if (!tx->sta)
1058 		tx->sta = sta_info_get(local, hdr->addr1);
1059 
1060 	if (tx->sta && ieee80211_is_data_qos(hdr->frame_control) &&
1061 	    (local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION)) {
1062 		unsigned long flags;
1063 		struct tid_ampdu_tx *tid_tx;
1064 
1065 		qc = ieee80211_get_qos_ctl(hdr);
1066 		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
1067 
1068 		spin_lock_irqsave(&tx->sta->lock, flags);
1069 		/*
1070 		 * XXX: This spinlock could be fairly expensive, but see the
1071 		 *	comment in agg-tx.c:ieee80211_agg_tx_operational().
1072 		 *	One way to solve this would be to do something RCU-like
1073 		 *	for managing the tid_tx struct and using atomic bitops
1074 		 *	for the actual state -- by introducing an actual
1075 		 *	'operational' bit that would be possible. It would
1076 		 *	require changing ieee80211_agg_tx_operational() to
1077 		 *	set that bit, and changing the way tid_tx is managed
1078 		 *	everywhere, including races between that bit and
1079 		 *	tid_tx going away (tid_tx being added can be easily
1080 		 *	committed to memory before the 'operational' bit).
1081 		 */
1082 		tid_tx = tx->sta->ampdu_mlme.tid_tx[tid];
1083 		state = &tx->sta->ampdu_mlme.tid_state_tx[tid];
1084 		if (*state == HT_AGG_STATE_OPERATIONAL) {
1085 			info->flags |= IEEE80211_TX_CTL_AMPDU;
1086 		} else if (*state != HT_AGG_STATE_IDLE) {
1087 			/* in progress */
1088 			queued = true;
1089 			info->control.vif = &sdata->vif;
1090 			info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1091 			__skb_queue_tail(&tid_tx->pending, skb);
1092 		}
1093 		spin_unlock_irqrestore(&tx->sta->lock, flags);
1094 
1095 		if (unlikely(queued))
1096 			return TX_QUEUED;
1097 	}
1098 
1099 	if (is_multicast_ether_addr(hdr->addr1)) {
1100 		tx->flags &= ~IEEE80211_TX_UNICAST;
1101 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
1102 	} else {
1103 		tx->flags |= IEEE80211_TX_UNICAST;
1104 		if (unlikely(local->wifi_wme_noack_test))
1105 			info->flags |= IEEE80211_TX_CTL_NO_ACK;
1106 		else
1107 			info->flags &= ~IEEE80211_TX_CTL_NO_ACK;
1108 	}
1109 
1110 	if (tx->flags & IEEE80211_TX_FRAGMENTED) {
1111 		if ((tx->flags & IEEE80211_TX_UNICAST) &&
1112 		    skb->len + FCS_LEN > local->hw.wiphy->frag_threshold &&
1113 		    !(info->flags & IEEE80211_TX_CTL_AMPDU))
1114 			tx->flags |= IEEE80211_TX_FRAGMENTED;
1115 		else
1116 			tx->flags &= ~IEEE80211_TX_FRAGMENTED;
1117 	}
1118 
1119 	if (!tx->sta)
1120 		info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
1121 	else if (test_and_clear_sta_flags(tx->sta, WLAN_STA_CLEAR_PS_FILT))
1122 		info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
1123 
1124 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
1125 	if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
1126 		u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
1127 		tx->ethertype = (pos[0] << 8) | pos[1];
1128 	}
1129 	info->flags |= IEEE80211_TX_CTL_FIRST_FRAGMENT;
1130 
1131 	return TX_CONTINUE;
1132 }
1133 
1134 static int __ieee80211_tx(struct ieee80211_local *local,
1135 			  struct sk_buff **skbp,
1136 			  struct sta_info *sta,
1137 			  bool txpending)
1138 {
1139 	struct sk_buff *skb = *skbp, *next;
1140 	struct ieee80211_tx_info *info;
1141 	struct ieee80211_sub_if_data *sdata;
1142 	unsigned long flags;
1143 	int ret, len;
1144 	bool fragm = false;
1145 
1146 	while (skb) {
1147 		int q = skb_get_queue_mapping(skb);
1148 
1149 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
1150 		ret = IEEE80211_TX_OK;
1151 		if (local->queue_stop_reasons[q] ||
1152 		    (!txpending && !skb_queue_empty(&local->pending[q])))
1153 			ret = IEEE80211_TX_PENDING;
1154 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
1155 		if (ret != IEEE80211_TX_OK)
1156 			return ret;
1157 
1158 		info = IEEE80211_SKB_CB(skb);
1159 
1160 		if (fragm)
1161 			info->flags &= ~(IEEE80211_TX_CTL_CLEAR_PS_FILT |
1162 					 IEEE80211_TX_CTL_FIRST_FRAGMENT);
1163 
1164 		next = skb->next;
1165 		len = skb->len;
1166 
1167 		if (next)
1168 			info->flags |= IEEE80211_TX_CTL_MORE_FRAMES;
1169 
1170 		sdata = vif_to_sdata(info->control.vif);
1171 
1172 		switch (sdata->vif.type) {
1173 		case NL80211_IFTYPE_MONITOR:
1174 			info->control.vif = NULL;
1175 			break;
1176 		case NL80211_IFTYPE_AP_VLAN:
1177 			info->control.vif = &container_of(sdata->bss,
1178 				struct ieee80211_sub_if_data, u.ap)->vif;
1179 			break;
1180 		default:
1181 			/* keep */
1182 			break;
1183 		}
1184 
1185 		ret = drv_tx(local, skb);
1186 		if (WARN_ON(ret != NETDEV_TX_OK && skb->len != len)) {
1187 			dev_kfree_skb(skb);
1188 			ret = NETDEV_TX_OK;
1189 		}
1190 		if (ret != NETDEV_TX_OK) {
1191 			info->control.vif = &sdata->vif;
1192 			return IEEE80211_TX_AGAIN;
1193 		}
1194 
1195 		*skbp = skb = next;
1196 		ieee80211_led_tx(local, 1);
1197 		fragm = true;
1198 	}
1199 
1200 	return IEEE80211_TX_OK;
1201 }
1202 
1203 /*
1204  * Invoke TX handlers, return 0 on success and non-zero if the
1205  * frame was dropped or queued.
1206  */
1207 static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
1208 {
1209 	struct sk_buff *skb = tx->skb;
1210 	ieee80211_tx_result res = TX_DROP;
1211 
1212 #define CALL_TXH(txh) \
1213 	do {				\
1214 		res = txh(tx);		\
1215 		if (res != TX_CONTINUE)	\
1216 			goto txh_done;	\
1217 	} while (0)
1218 
1219 	CALL_TXH(ieee80211_tx_h_check_assoc);
1220 	CALL_TXH(ieee80211_tx_h_ps_buf);
1221 	CALL_TXH(ieee80211_tx_h_select_key);
1222 	CALL_TXH(ieee80211_tx_h_michael_mic_add);
1223 	if (!(tx->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL))
1224 		CALL_TXH(ieee80211_tx_h_rate_ctrl);
1225 	CALL_TXH(ieee80211_tx_h_misc);
1226 	CALL_TXH(ieee80211_tx_h_sequence);
1227 	CALL_TXH(ieee80211_tx_h_fragment);
1228 	/* handlers after fragment must be aware of tx info fragmentation! */
1229 	CALL_TXH(ieee80211_tx_h_stats);
1230 	CALL_TXH(ieee80211_tx_h_encrypt);
1231 	CALL_TXH(ieee80211_tx_h_calculate_duration);
1232 #undef CALL_TXH
1233 
1234  txh_done:
1235 	if (unlikely(res == TX_DROP)) {
1236 		I802_DEBUG_INC(tx->local->tx_handlers_drop);
1237 		while (skb) {
1238 			struct sk_buff *next;
1239 
1240 			next = skb->next;
1241 			dev_kfree_skb(skb);
1242 			skb = next;
1243 		}
1244 		return -1;
1245 	} else if (unlikely(res == TX_QUEUED)) {
1246 		I802_DEBUG_INC(tx->local->tx_handlers_queued);
1247 		return -1;
1248 	}
1249 
1250 	return 0;
1251 }
1252 
1253 static void ieee80211_tx(struct ieee80211_sub_if_data *sdata,
1254 			 struct sk_buff *skb, bool txpending)
1255 {
1256 	struct ieee80211_local *local = sdata->local;
1257 	struct ieee80211_tx_data tx;
1258 	ieee80211_tx_result res_prepare;
1259 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1260 	struct sk_buff *next;
1261 	unsigned long flags;
1262 	int ret, retries;
1263 	u16 queue;
1264 
1265 	queue = skb_get_queue_mapping(skb);
1266 
1267 	if (unlikely(skb->len < 10)) {
1268 		dev_kfree_skb(skb);
1269 		return;
1270 	}
1271 
1272 	rcu_read_lock();
1273 
1274 	/* initialises tx */
1275 	res_prepare = ieee80211_tx_prepare(sdata, &tx, skb);
1276 
1277 	if (unlikely(res_prepare == TX_DROP)) {
1278 		dev_kfree_skb(skb);
1279 		rcu_read_unlock();
1280 		return;
1281 	} else if (unlikely(res_prepare == TX_QUEUED)) {
1282 		rcu_read_unlock();
1283 		return;
1284 	}
1285 
1286 	tx.channel = local->hw.conf.channel;
1287 	info->band = tx.channel->band;
1288 
1289 	if (invoke_tx_handlers(&tx))
1290 		goto out;
1291 
1292 	retries = 0;
1293  retry:
1294 	ret = __ieee80211_tx(local, &tx.skb, tx.sta, txpending);
1295 	switch (ret) {
1296 	case IEEE80211_TX_OK:
1297 		break;
1298 	case IEEE80211_TX_AGAIN:
1299 		/*
1300 		 * Since there are no fragmented frames on A-MPDU
1301 		 * queues, there's no reason for a driver to reject
1302 		 * a frame there, warn and drop it.
1303 		 */
1304 		if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
1305 			goto drop;
1306 		/* fall through */
1307 	case IEEE80211_TX_PENDING:
1308 		skb = tx.skb;
1309 
1310 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
1311 
1312 		if (local->queue_stop_reasons[queue] ||
1313 		    !skb_queue_empty(&local->pending[queue])) {
1314 			/*
1315 			 * if queue is stopped, queue up frames for later
1316 			 * transmission from the tasklet
1317 			 */
1318 			do {
1319 				next = skb->next;
1320 				skb->next = NULL;
1321 				if (unlikely(txpending))
1322 					__skb_queue_head(&local->pending[queue],
1323 							 skb);
1324 				else
1325 					__skb_queue_tail(&local->pending[queue],
1326 							 skb);
1327 			} while ((skb = next));
1328 
1329 			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
1330 					       flags);
1331 		} else {
1332 			/*
1333 			 * otherwise retry, but this is a race condition or
1334 			 * a driver bug (which we warn about if it persists)
1335 			 */
1336 			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
1337 					       flags);
1338 
1339 			retries++;
1340 			if (WARN(retries > 10, "tx refused but queue active\n"))
1341 				goto drop;
1342 			goto retry;
1343 		}
1344 	}
1345  out:
1346 	rcu_read_unlock();
1347 	return;
1348 
1349  drop:
1350 	rcu_read_unlock();
1351 
1352 	skb = tx.skb;
1353 	while (skb) {
1354 		next = skb->next;
1355 		dev_kfree_skb(skb);
1356 		skb = next;
1357 	}
1358 }
1359 
1360 /* device xmit handlers */
1361 
1362 static int ieee80211_skb_resize(struct ieee80211_local *local,
1363 				struct sk_buff *skb,
1364 				int head_need, bool may_encrypt)
1365 {
1366 	int tail_need = 0;
1367 
1368 	/*
1369 	 * This could be optimised, devices that do full hardware
1370 	 * crypto (including TKIP MMIC) need no tailroom... But we
1371 	 * have no drivers for such devices currently.
1372 	 */
1373 	if (may_encrypt) {
1374 		tail_need = IEEE80211_ENCRYPT_TAILROOM;
1375 		tail_need -= skb_tailroom(skb);
1376 		tail_need = max_t(int, tail_need, 0);
1377 	}
1378 
1379 	if (head_need || tail_need) {
1380 		/* Sorry. Can't account for this any more */
1381 		skb_orphan(skb);
1382 	}
1383 
1384 	if (skb_header_cloned(skb))
1385 		I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
1386 	else
1387 		I802_DEBUG_INC(local->tx_expand_skb_head);
1388 
1389 	if (pskb_expand_head(skb, head_need, tail_need, GFP_ATOMIC)) {
1390 		printk(KERN_DEBUG "%s: failed to reallocate TX buffer\n",
1391 		       wiphy_name(local->hw.wiphy));
1392 		return -ENOMEM;
1393 	}
1394 
1395 	/* update truesize too */
1396 	skb->truesize += head_need + tail_need;
1397 
1398 	return 0;
1399 }
1400 
1401 static bool need_dynamic_ps(struct ieee80211_local *local)
1402 {
1403 	/* driver doesn't support power save */
1404 	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_PS))
1405 		return false;
1406 
1407 	/* hardware does dynamic power save */
1408 	if (local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)
1409 		return false;
1410 
1411 	/* dynamic power save disabled */
1412 	if (local->hw.conf.dynamic_ps_timeout <= 0)
1413 		return false;
1414 
1415 	/* we are scanning, don't enable power save */
1416 	if (local->scanning)
1417 		return false;
1418 
1419 	if (!local->ps_sdata)
1420 		return false;
1421 
1422 	/* No point if we're going to suspend */
1423 	if (local->quiescing)
1424 		return false;
1425 
1426 	return true;
1427 }
1428 
1429 static void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
1430 			   struct sk_buff *skb)
1431 {
1432 	struct ieee80211_local *local = sdata->local;
1433 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1434 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1435 	struct ieee80211_sub_if_data *tmp_sdata;
1436 	int headroom;
1437 	bool may_encrypt;
1438 
1439 	if (need_dynamic_ps(local)) {
1440 		if (local->hw.conf.flags & IEEE80211_CONF_PS) {
1441 			ieee80211_stop_queues_by_reason(&local->hw,
1442 					IEEE80211_QUEUE_STOP_REASON_PS);
1443 			ieee80211_queue_work(&local->hw,
1444 					&local->dynamic_ps_disable_work);
1445 		}
1446 
1447 		mod_timer(&local->dynamic_ps_timer, jiffies +
1448 		        msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
1449 	}
1450 
1451 	rcu_read_lock();
1452 
1453 	if (unlikely(sdata->vif.type == NL80211_IFTYPE_MONITOR)) {
1454 		int hdrlen;
1455 		u16 len_rthdr;
1456 
1457 		info->flags |= IEEE80211_TX_CTL_INJECTED;
1458 
1459 		len_rthdr = ieee80211_get_radiotap_len(skb->data);
1460 		hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
1461 		hdrlen = ieee80211_hdrlen(hdr->frame_control);
1462 
1463 		/* check the header is complete in the frame */
1464 		if (likely(skb->len >= len_rthdr + hdrlen)) {
1465 			/*
1466 			 * We process outgoing injected frames that have a
1467 			 * local address we handle as though they are our
1468 			 * own frames.
1469 			 * This code here isn't entirely correct, the local
1470 			 * MAC address is not necessarily enough to find
1471 			 * the interface to use; for that proper VLAN/WDS
1472 			 * support we will need a different mechanism.
1473 			 */
1474 
1475 			list_for_each_entry_rcu(tmp_sdata, &local->interfaces,
1476 						list) {
1477 				if (!netif_running(tmp_sdata->dev))
1478 					continue;
1479 				if (tmp_sdata->vif.type != NL80211_IFTYPE_AP)
1480 					continue;
1481 				if (compare_ether_addr(tmp_sdata->dev->dev_addr,
1482 						       hdr->addr2) == 0) {
1483 					sdata = tmp_sdata;
1484 					break;
1485 				}
1486 			}
1487 		}
1488 	}
1489 
1490 	may_encrypt = !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT);
1491 
1492 	headroom = local->tx_headroom;
1493 	if (may_encrypt)
1494 		headroom += IEEE80211_ENCRYPT_HEADROOM;
1495 	headroom -= skb_headroom(skb);
1496 	headroom = max_t(int, 0, headroom);
1497 
1498 	if (ieee80211_skb_resize(local, skb, headroom, may_encrypt)) {
1499 		dev_kfree_skb(skb);
1500 		rcu_read_unlock();
1501 		return;
1502 	}
1503 
1504 	info->control.vif = &sdata->vif;
1505 
1506 	if (ieee80211_vif_is_mesh(&sdata->vif) &&
1507 	    ieee80211_is_data(hdr->frame_control) &&
1508 		!is_multicast_ether_addr(hdr->addr1))
1509 			if (mesh_nexthop_lookup(skb, sdata)) {
1510 				/* skb queued: don't free */
1511 				rcu_read_unlock();
1512 				return;
1513 			}
1514 
1515 	ieee80211_set_qos_hdr(local, skb);
1516 	ieee80211_tx(sdata, skb, false);
1517 	rcu_read_unlock();
1518 }
1519 
1520 netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
1521 					 struct net_device *dev)
1522 {
1523 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
1524 	struct ieee80211_channel *chan = local->hw.conf.channel;
1525 	struct ieee80211_radiotap_header *prthdr =
1526 		(struct ieee80211_radiotap_header *)skb->data;
1527 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1528 	u16 len_rthdr;
1529 
1530 	/*
1531 	 * Frame injection is not allowed if beaconing is not allowed
1532 	 * or if we need radar detection. Beaconing is usually not allowed when
1533 	 * the mode or operation (Adhoc, AP, Mesh) does not support DFS.
1534 	 * Passive scan is also used in world regulatory domains where
1535 	 * your country is not known and as such it should be treated as
1536 	 * NO TX unless the channel is explicitly allowed in which case
1537 	 * your current regulatory domain would not have the passive scan
1538 	 * flag.
1539 	 *
1540 	 * Since AP mode uses monitor interfaces to inject/TX management
1541 	 * frames we can make AP mode the exception to this rule once it
1542 	 * supports radar detection as its implementation can deal with
1543 	 * radar detection by itself. We can do that later by adding a
1544 	 * monitor flag interfaces used for AP support.
1545 	 */
1546 	if ((chan->flags & (IEEE80211_CHAN_NO_IBSS | IEEE80211_CHAN_RADAR |
1547 	     IEEE80211_CHAN_PASSIVE_SCAN)))
1548 		goto fail;
1549 
1550 	/* check for not even having the fixed radiotap header part */
1551 	if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
1552 		goto fail; /* too short to be possibly valid */
1553 
1554 	/* is it a header version we can trust to find length from? */
1555 	if (unlikely(prthdr->it_version))
1556 		goto fail; /* only version 0 is supported */
1557 
1558 	/* then there must be a radiotap header with a length we can use */
1559 	len_rthdr = ieee80211_get_radiotap_len(skb->data);
1560 
1561 	/* does the skb contain enough to deliver on the alleged length? */
1562 	if (unlikely(skb->len < len_rthdr))
1563 		goto fail; /* skb too short for claimed rt header extent */
1564 
1565 	/*
1566 	 * fix up the pointers accounting for the radiotap
1567 	 * header still being in there.  We are being given
1568 	 * a precooked IEEE80211 header so no need for
1569 	 * normal processing
1570 	 */
1571 	skb_set_mac_header(skb, len_rthdr);
1572 	/*
1573 	 * these are just fixed to the end of the rt area since we
1574 	 * don't have any better information and at this point, nobody cares
1575 	 */
1576 	skb_set_network_header(skb, len_rthdr);
1577 	skb_set_transport_header(skb, len_rthdr);
1578 
1579 	memset(info, 0, sizeof(*info));
1580 
1581 	info->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
1582 
1583 	/* pass the radiotap header up to xmit */
1584 	ieee80211_xmit(IEEE80211_DEV_TO_SUB_IF(dev), skb);
1585 	return NETDEV_TX_OK;
1586 
1587 fail:
1588 	dev_kfree_skb(skb);
1589 	return NETDEV_TX_OK; /* meaning, we dealt with the skb */
1590 }
1591 
1592 /**
1593  * ieee80211_subif_start_xmit - netif start_xmit function for Ethernet-type
1594  * subinterfaces (wlan#, WDS, and VLAN interfaces)
1595  * @skb: packet to be sent
1596  * @dev: incoming interface
1597  *
1598  * Returns: 0 on success (and frees skb in this case) or 1 on failure (skb will
1599  * not be freed, and caller is responsible for either retrying later or freeing
1600  * skb).
1601  *
1602  * This function takes in an Ethernet header and encapsulates it with suitable
1603  * IEEE 802.11 header based on which interface the packet is coming in. The
1604  * encapsulated packet will then be passed to master interface, wlan#.11, for
1605  * transmission (through low-level driver).
1606  */
1607 netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
1608 				    struct net_device *dev)
1609 {
1610 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
1611 	struct ieee80211_local *local = sdata->local;
1612 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1613 	int ret = NETDEV_TX_BUSY, head_need;
1614 	u16 ethertype, hdrlen,  meshhdrlen = 0;
1615 	__le16 fc;
1616 	struct ieee80211_hdr hdr;
1617 	struct ieee80211s_hdr mesh_hdr;
1618 	const u8 *encaps_data;
1619 	int encaps_len, skip_header_bytes;
1620 	int nh_pos, h_pos;
1621 	struct sta_info *sta = NULL;
1622 	u32 sta_flags = 0;
1623 
1624 	if (unlikely(skb->len < ETH_HLEN)) {
1625 		ret = NETDEV_TX_OK;
1626 		goto fail;
1627 	}
1628 
1629 	nh_pos = skb_network_header(skb) - skb->data;
1630 	h_pos = skb_transport_header(skb) - skb->data;
1631 
1632 	/* convert Ethernet header to proper 802.11 header (based on
1633 	 * operation mode) */
1634 	ethertype = (skb->data[12] << 8) | skb->data[13];
1635 	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
1636 
1637 	switch (sdata->vif.type) {
1638 	case NL80211_IFTYPE_AP_VLAN:
1639 		rcu_read_lock();
1640 		sta = rcu_dereference(sdata->u.vlan.sta);
1641 		if (sta) {
1642 			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
1643 			/* RA TA DA SA */
1644 			memcpy(hdr.addr1, sta->sta.addr, ETH_ALEN);
1645 			memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1646 			memcpy(hdr.addr3, skb->data, ETH_ALEN);
1647 			memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
1648 			hdrlen = 30;
1649 			sta_flags = get_sta_flags(sta);
1650 		}
1651 		rcu_read_unlock();
1652 		if (sta)
1653 			break;
1654 		/* fall through */
1655 	case NL80211_IFTYPE_AP:
1656 		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
1657 		/* DA BSSID SA */
1658 		memcpy(hdr.addr1, skb->data, ETH_ALEN);
1659 		memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1660 		memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
1661 		hdrlen = 24;
1662 		break;
1663 	case NL80211_IFTYPE_WDS:
1664 		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
1665 		/* RA TA DA SA */
1666 		memcpy(hdr.addr1, sdata->u.wds.remote_addr, ETH_ALEN);
1667 		memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1668 		memcpy(hdr.addr3, skb->data, ETH_ALEN);
1669 		memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
1670 		hdrlen = 30;
1671 		break;
1672 #ifdef CONFIG_MAC80211_MESH
1673 	case NL80211_IFTYPE_MESH_POINT:
1674 		if (!sdata->u.mesh.mshcfg.dot11MeshTTL) {
1675 			/* Do not send frames with mesh_ttl == 0 */
1676 			sdata->u.mesh.mshstats.dropped_frames_ttl++;
1677 			ret = NETDEV_TX_OK;
1678 			goto fail;
1679 		}
1680 
1681 		if (compare_ether_addr(dev->dev_addr,
1682 					  skb->data + ETH_ALEN) == 0) {
1683 			hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
1684 					skb->data, skb->data + ETH_ALEN);
1685 			meshhdrlen = ieee80211_new_mesh_header(&mesh_hdr,
1686 					sdata, NULL, NULL, NULL);
1687 		} else {
1688 			/* packet from other interface */
1689 			struct mesh_path *mppath;
1690 			int is_mesh_mcast = 1;
1691 			const u8 *mesh_da;
1692 
1693 			rcu_read_lock();
1694 			if (is_multicast_ether_addr(skb->data))
1695 				/* DA TA mSA AE:SA */
1696 				mesh_da = skb->data;
1697 			else {
1698 				static const u8 bcast[ETH_ALEN] =
1699 					{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
1700 
1701 				mppath = mpp_path_lookup(skb->data, sdata);
1702 				if (mppath) {
1703 					/* RA TA mDA mSA AE:DA SA */
1704 					mesh_da = mppath->mpp;
1705 					is_mesh_mcast = 0;
1706 				} else {
1707 					/* DA TA mSA AE:SA */
1708 					mesh_da = bcast;
1709 				}
1710 			}
1711 			hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
1712 					mesh_da, dev->dev_addr);
1713 			rcu_read_unlock();
1714 			if (is_mesh_mcast)
1715 				meshhdrlen =
1716 					ieee80211_new_mesh_header(&mesh_hdr,
1717 							sdata,
1718 							skb->data + ETH_ALEN,
1719 							NULL,
1720 							NULL);
1721 			else
1722 				meshhdrlen =
1723 					ieee80211_new_mesh_header(&mesh_hdr,
1724 							sdata,
1725 							NULL,
1726 							skb->data,
1727 							skb->data + ETH_ALEN);
1728 
1729 		}
1730 		break;
1731 #endif
1732 	case NL80211_IFTYPE_STATION:
1733 		memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
1734 		if (sdata->u.mgd.use_4addr && ethertype != ETH_P_PAE) {
1735 			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
1736 			/* RA TA DA SA */
1737 			memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1738 			memcpy(hdr.addr3, skb->data, ETH_ALEN);
1739 			memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
1740 			hdrlen = 30;
1741 		} else {
1742 			fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
1743 			/* BSSID SA DA */
1744 			memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
1745 			memcpy(hdr.addr3, skb->data, ETH_ALEN);
1746 			hdrlen = 24;
1747 		}
1748 		break;
1749 	case NL80211_IFTYPE_ADHOC:
1750 		/* DA SA BSSID */
1751 		memcpy(hdr.addr1, skb->data, ETH_ALEN);
1752 		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
1753 		memcpy(hdr.addr3, sdata->u.ibss.bssid, ETH_ALEN);
1754 		hdrlen = 24;
1755 		break;
1756 	default:
1757 		ret = NETDEV_TX_OK;
1758 		goto fail;
1759 	}
1760 
1761 	/*
1762 	 * There's no need to try to look up the destination
1763 	 * if it is a multicast address (which can only happen
1764 	 * in AP mode)
1765 	 */
1766 	if (!is_multicast_ether_addr(hdr.addr1)) {
1767 		rcu_read_lock();
1768 		sta = sta_info_get(local, hdr.addr1);
1769 		/* XXX: in the future, use sdata to look up the sta */
1770 		if (sta && sta->sdata == sdata)
1771 			sta_flags = get_sta_flags(sta);
1772 		rcu_read_unlock();
1773 	}
1774 
1775 	/* receiver and we are QoS enabled, use a QoS type frame */
1776 	if ((sta_flags & WLAN_STA_WME) && local->hw.queues >= 4) {
1777 		fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
1778 		hdrlen += 2;
1779 	}
1780 
1781 	/*
1782 	 * Drop unicast frames to unauthorised stations unless they are
1783 	 * EAPOL frames from the local station.
1784 	 */
1785 	if (!ieee80211_vif_is_mesh(&sdata->vif) &&
1786 		unlikely(!is_multicast_ether_addr(hdr.addr1) &&
1787 		      !(sta_flags & WLAN_STA_AUTHORIZED) &&
1788 		      !(ethertype == ETH_P_PAE &&
1789 		       compare_ether_addr(dev->dev_addr,
1790 					  skb->data + ETH_ALEN) == 0))) {
1791 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
1792 		if (net_ratelimit())
1793 			printk(KERN_DEBUG "%s: dropped frame to %pM"
1794 			       " (unauthorized port)\n", dev->name,
1795 			       hdr.addr1);
1796 #endif
1797 
1798 		I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);
1799 
1800 		ret = NETDEV_TX_OK;
1801 		goto fail;
1802 	}
1803 
1804 	hdr.frame_control = fc;
1805 	hdr.duration_id = 0;
1806 	hdr.seq_ctrl = 0;
1807 
1808 	skip_header_bytes = ETH_HLEN;
1809 	if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
1810 		encaps_data = bridge_tunnel_header;
1811 		encaps_len = sizeof(bridge_tunnel_header);
1812 		skip_header_bytes -= 2;
1813 	} else if (ethertype >= 0x600) {
1814 		encaps_data = rfc1042_header;
1815 		encaps_len = sizeof(rfc1042_header);
1816 		skip_header_bytes -= 2;
1817 	} else {
1818 		encaps_data = NULL;
1819 		encaps_len = 0;
1820 	}
1821 
1822 	skb_pull(skb, skip_header_bytes);
1823 	nh_pos -= skip_header_bytes;
1824 	h_pos -= skip_header_bytes;
1825 
1826 	head_need = hdrlen + encaps_len + meshhdrlen - skb_headroom(skb);
1827 
1828 	/*
1829 	 * So we need to modify the skb header and hence need a copy of
1830 	 * that. The head_need variable above doesn't, so far, include
1831 	 * the needed header space that we don't need right away. If we
1832 	 * can, then we don't reallocate right now but only after the
1833 	 * frame arrives at the master device (if it does...)
1834 	 *
1835 	 * If we cannot, however, then we will reallocate to include all
1836 	 * the ever needed space. Also, if we need to reallocate it anyway,
1837 	 * make it big enough for everything we may ever need.
1838 	 */
1839 
1840 	if (head_need > 0 || skb_cloned(skb)) {
1841 		head_need += IEEE80211_ENCRYPT_HEADROOM;
1842 		head_need += local->tx_headroom;
1843 		head_need = max_t(int, 0, head_need);
1844 		if (ieee80211_skb_resize(local, skb, head_need, true))
1845 			goto fail;
1846 	}
1847 
1848 	if (encaps_data) {
1849 		memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
1850 		nh_pos += encaps_len;
1851 		h_pos += encaps_len;
1852 	}
1853 
1854 	if (meshhdrlen > 0) {
1855 		memcpy(skb_push(skb, meshhdrlen), &mesh_hdr, meshhdrlen);
1856 		nh_pos += meshhdrlen;
1857 		h_pos += meshhdrlen;
1858 	}
1859 
1860 	if (ieee80211_is_data_qos(fc)) {
1861 		__le16 *qos_control;
1862 
1863 		qos_control = (__le16*) skb_push(skb, 2);
1864 		memcpy(skb_push(skb, hdrlen - 2), &hdr, hdrlen - 2);
1865 		/*
1866 		 * Maybe we could actually set some fields here, for now just
1867 		 * initialise to zero to indicate no special operation.
1868 		 */
1869 		*qos_control = 0;
1870 	} else
1871 		memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
1872 
1873 	nh_pos += hdrlen;
1874 	h_pos += hdrlen;
1875 
1876 	dev->stats.tx_packets++;
1877 	dev->stats.tx_bytes += skb->len;
1878 
1879 	/* Update skb pointers to various headers since this modified frame
1880 	 * is going to go through Linux networking code that may potentially
1881 	 * need things like pointer to IP header. */
1882 	skb_set_mac_header(skb, 0);
1883 	skb_set_network_header(skb, nh_pos);
1884 	skb_set_transport_header(skb, h_pos);
1885 
1886 	memset(info, 0, sizeof(*info));
1887 
1888 	dev->trans_start = jiffies;
1889 	ieee80211_xmit(sdata, skb);
1890 
1891 	return NETDEV_TX_OK;
1892 
1893  fail:
1894 	if (ret == NETDEV_TX_OK)
1895 		dev_kfree_skb(skb);
1896 
1897 	return ret;
1898 }
1899 
1900 
1901 /*
1902  * ieee80211_clear_tx_pending may not be called in a context where
1903  * it is possible that it packets could come in again.
1904  */
1905 void ieee80211_clear_tx_pending(struct ieee80211_local *local)
1906 {
1907 	int i;
1908 
1909 	for (i = 0; i < local->hw.queues; i++)
1910 		skb_queue_purge(&local->pending[i]);
1911 }
1912 
1913 static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
1914 				     struct sk_buff *skb)
1915 {
1916 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1917 	struct ieee80211_sub_if_data *sdata;
1918 	struct sta_info *sta;
1919 	struct ieee80211_hdr *hdr;
1920 	int ret;
1921 	bool result = true;
1922 
1923 	sdata = vif_to_sdata(info->control.vif);
1924 
1925 	if (info->flags & IEEE80211_TX_INTFL_NEED_TXPROCESSING) {
1926 		ieee80211_tx(sdata, skb, true);
1927 	} else {
1928 		hdr = (struct ieee80211_hdr *)skb->data;
1929 		sta = sta_info_get(local, hdr->addr1);
1930 
1931 		ret = __ieee80211_tx(local, &skb, sta, true);
1932 		if (ret != IEEE80211_TX_OK)
1933 			result = false;
1934 	}
1935 
1936 	return result;
1937 }
1938 
1939 /*
1940  * Transmit all pending packets. Called from tasklet.
1941  */
1942 void ieee80211_tx_pending(unsigned long data)
1943 {
1944 	struct ieee80211_local *local = (struct ieee80211_local *)data;
1945 	unsigned long flags;
1946 	int i;
1947 	bool txok;
1948 
1949 	rcu_read_lock();
1950 
1951 	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
1952 	for (i = 0; i < local->hw.queues; i++) {
1953 		/*
1954 		 * If queue is stopped by something other than due to pending
1955 		 * frames, or we have no pending frames, proceed to next queue.
1956 		 */
1957 		if (local->queue_stop_reasons[i] ||
1958 		    skb_queue_empty(&local->pending[i]))
1959 			continue;
1960 
1961 		while (!skb_queue_empty(&local->pending[i])) {
1962 			struct sk_buff *skb = __skb_dequeue(&local->pending[i]);
1963 			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1964 			struct ieee80211_sub_if_data *sdata;
1965 
1966 			if (WARN_ON(!info->control.vif)) {
1967 				kfree_skb(skb);
1968 				continue;
1969 			}
1970 
1971 			sdata = vif_to_sdata(info->control.vif);
1972 			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
1973 						flags);
1974 
1975 			txok = ieee80211_tx_pending_skb(local, skb);
1976 			if (!txok)
1977 				__skb_queue_head(&local->pending[i], skb);
1978 			spin_lock_irqsave(&local->queue_stop_reason_lock,
1979 					  flags);
1980 			if (!txok)
1981 				break;
1982 		}
1983 	}
1984 	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
1985 
1986 	rcu_read_unlock();
1987 }
1988 
1989 /* functions for drivers to get certain frames */
1990 
1991 static void ieee80211_beacon_add_tim(struct ieee80211_if_ap *bss,
1992 				     struct sk_buff *skb,
1993 				     struct beacon_data *beacon)
1994 {
1995 	u8 *pos, *tim;
1996 	int aid0 = 0;
1997 	int i, have_bits = 0, n1, n2;
1998 
1999 	/* Generate bitmap for TIM only if there are any STAs in power save
2000 	 * mode. */
2001 	if (atomic_read(&bss->num_sta_ps) > 0)
2002 		/* in the hope that this is faster than
2003 		 * checking byte-for-byte */
2004 		have_bits = !bitmap_empty((unsigned long*)bss->tim,
2005 					  IEEE80211_MAX_AID+1);
2006 
2007 	if (bss->dtim_count == 0)
2008 		bss->dtim_count = beacon->dtim_period - 1;
2009 	else
2010 		bss->dtim_count--;
2011 
2012 	tim = pos = (u8 *) skb_put(skb, 6);
2013 	*pos++ = WLAN_EID_TIM;
2014 	*pos++ = 4;
2015 	*pos++ = bss->dtim_count;
2016 	*pos++ = beacon->dtim_period;
2017 
2018 	if (bss->dtim_count == 0 && !skb_queue_empty(&bss->ps_bc_buf))
2019 		aid0 = 1;
2020 
2021 	if (have_bits) {
2022 		/* Find largest even number N1 so that bits numbered 1 through
2023 		 * (N1 x 8) - 1 in the bitmap are 0 and number N2 so that bits
2024 		 * (N2 + 1) x 8 through 2007 are 0. */
2025 		n1 = 0;
2026 		for (i = 0; i < IEEE80211_MAX_TIM_LEN; i++) {
2027 			if (bss->tim[i]) {
2028 				n1 = i & 0xfe;
2029 				break;
2030 			}
2031 		}
2032 		n2 = n1;
2033 		for (i = IEEE80211_MAX_TIM_LEN - 1; i >= n1; i--) {
2034 			if (bss->tim[i]) {
2035 				n2 = i;
2036 				break;
2037 			}
2038 		}
2039 
2040 		/* Bitmap control */
2041 		*pos++ = n1 | aid0;
2042 		/* Part Virt Bitmap */
2043 		memcpy(pos, bss->tim + n1, n2 - n1 + 1);
2044 
2045 		tim[1] = n2 - n1 + 4;
2046 		skb_put(skb, n2 - n1);
2047 	} else {
2048 		*pos++ = aid0; /* Bitmap control */
2049 		*pos++ = 0; /* Part Virt Bitmap */
2050 	}
2051 }
2052 
2053 struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
2054 					 struct ieee80211_vif *vif,
2055 					 u16 *tim_offset, u16 *tim_length)
2056 {
2057 	struct ieee80211_local *local = hw_to_local(hw);
2058 	struct sk_buff *skb = NULL;
2059 	struct ieee80211_tx_info *info;
2060 	struct ieee80211_sub_if_data *sdata = NULL;
2061 	struct ieee80211_if_ap *ap = NULL;
2062 	struct beacon_data *beacon;
2063 	struct ieee80211_supported_band *sband;
2064 	enum ieee80211_band band = local->hw.conf.channel->band;
2065 
2066 	sband = local->hw.wiphy->bands[band];
2067 
2068 	rcu_read_lock();
2069 
2070 	sdata = vif_to_sdata(vif);
2071 
2072 	if (tim_offset)
2073 		*tim_offset = 0;
2074 	if (tim_length)
2075 		*tim_length = 0;
2076 
2077 	if (sdata->vif.type == NL80211_IFTYPE_AP) {
2078 		ap = &sdata->u.ap;
2079 		beacon = rcu_dereference(ap->beacon);
2080 		if (ap && beacon) {
2081 			/*
2082 			 * headroom, head length,
2083 			 * tail length and maximum TIM length
2084 			 */
2085 			skb = dev_alloc_skb(local->tx_headroom +
2086 					    beacon->head_len +
2087 					    beacon->tail_len + 256);
2088 			if (!skb)
2089 				goto out;
2090 
2091 			skb_reserve(skb, local->tx_headroom);
2092 			memcpy(skb_put(skb, beacon->head_len), beacon->head,
2093 			       beacon->head_len);
2094 
2095 			/*
2096 			 * Not very nice, but we want to allow the driver to call
2097 			 * ieee80211_beacon_get() as a response to the set_tim()
2098 			 * callback. That, however, is already invoked under the
2099 			 * sta_lock to guarantee consistent and race-free update
2100 			 * of the tim bitmap in mac80211 and the driver.
2101 			 */
2102 			if (local->tim_in_locked_section) {
2103 				ieee80211_beacon_add_tim(ap, skb, beacon);
2104 			} else {
2105 				unsigned long flags;
2106 
2107 				spin_lock_irqsave(&local->sta_lock, flags);
2108 				ieee80211_beacon_add_tim(ap, skb, beacon);
2109 				spin_unlock_irqrestore(&local->sta_lock, flags);
2110 			}
2111 
2112 			if (tim_offset)
2113 				*tim_offset = beacon->head_len;
2114 			if (tim_length)
2115 				*tim_length = skb->len - beacon->head_len;
2116 
2117 			if (beacon->tail)
2118 				memcpy(skb_put(skb, beacon->tail_len),
2119 				       beacon->tail, beacon->tail_len);
2120 		} else
2121 			goto out;
2122 	} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
2123 		struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
2124 		struct ieee80211_hdr *hdr;
2125 		struct sk_buff *presp = rcu_dereference(ifibss->presp);
2126 
2127 		if (!presp)
2128 			goto out;
2129 
2130 		skb = skb_copy(presp, GFP_ATOMIC);
2131 		if (!skb)
2132 			goto out;
2133 
2134 		hdr = (struct ieee80211_hdr *) skb->data;
2135 		hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
2136 						 IEEE80211_STYPE_BEACON);
2137 	} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
2138 		struct ieee80211_mgmt *mgmt;
2139 		u8 *pos;
2140 
2141 		/* headroom, head length, tail length and maximum TIM length */
2142 		skb = dev_alloc_skb(local->tx_headroom + 400);
2143 		if (!skb)
2144 			goto out;
2145 
2146 		skb_reserve(skb, local->hw.extra_tx_headroom);
2147 		mgmt = (struct ieee80211_mgmt *)
2148 			skb_put(skb, 24 + sizeof(mgmt->u.beacon));
2149 		memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
2150 		mgmt->frame_control =
2151 		    cpu_to_le16(IEEE80211_FTYPE_MGMT | IEEE80211_STYPE_BEACON);
2152 		memset(mgmt->da, 0xff, ETH_ALEN);
2153 		memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
2154 		memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
2155 		mgmt->u.beacon.beacon_int =
2156 			cpu_to_le16(sdata->vif.bss_conf.beacon_int);
2157 		mgmt->u.beacon.capab_info = 0x0; /* 0x0 for MPs */
2158 
2159 		pos = skb_put(skb, 2);
2160 		*pos++ = WLAN_EID_SSID;
2161 		*pos++ = 0x0;
2162 
2163 		mesh_mgmt_ies_add(skb, sdata);
2164 	} else {
2165 		WARN_ON(1);
2166 		goto out;
2167 	}
2168 
2169 	info = IEEE80211_SKB_CB(skb);
2170 
2171 	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
2172 	info->band = band;
2173 	/*
2174 	 * XXX: For now, always use the lowest rate
2175 	 */
2176 	info->control.rates[0].idx = 0;
2177 	info->control.rates[0].count = 1;
2178 	info->control.rates[1].idx = -1;
2179 	info->control.rates[2].idx = -1;
2180 	info->control.rates[3].idx = -1;
2181 	info->control.rates[4].idx = -1;
2182 	BUILD_BUG_ON(IEEE80211_TX_MAX_RATES != 5);
2183 
2184 	info->control.vif = vif;
2185 
2186 	info->flags |= IEEE80211_TX_CTL_NO_ACK;
2187 	info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
2188 	info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
2189  out:
2190 	rcu_read_unlock();
2191 	return skb;
2192 }
2193 EXPORT_SYMBOL(ieee80211_beacon_get_tim);
2194 
2195 void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
2196 		       const void *frame, size_t frame_len,
2197 		       const struct ieee80211_tx_info *frame_txctl,
2198 		       struct ieee80211_rts *rts)
2199 {
2200 	const struct ieee80211_hdr *hdr = frame;
2201 
2202 	rts->frame_control =
2203 	    cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
2204 	rts->duration = ieee80211_rts_duration(hw, vif, frame_len,
2205 					       frame_txctl);
2206 	memcpy(rts->ra, hdr->addr1, sizeof(rts->ra));
2207 	memcpy(rts->ta, hdr->addr2, sizeof(rts->ta));
2208 }
2209 EXPORT_SYMBOL(ieee80211_rts_get);
2210 
2211 void ieee80211_ctstoself_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
2212 			     const void *frame, size_t frame_len,
2213 			     const struct ieee80211_tx_info *frame_txctl,
2214 			     struct ieee80211_cts *cts)
2215 {
2216 	const struct ieee80211_hdr *hdr = frame;
2217 
2218 	cts->frame_control =
2219 	    cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS);
2220 	cts->duration = ieee80211_ctstoself_duration(hw, vif,
2221 						     frame_len, frame_txctl);
2222 	memcpy(cts->ra, hdr->addr1, sizeof(cts->ra));
2223 }
2224 EXPORT_SYMBOL(ieee80211_ctstoself_get);
2225 
2226 struct sk_buff *
2227 ieee80211_get_buffered_bc(struct ieee80211_hw *hw,
2228 			  struct ieee80211_vif *vif)
2229 {
2230 	struct ieee80211_local *local = hw_to_local(hw);
2231 	struct sk_buff *skb = NULL;
2232 	struct sta_info *sta;
2233 	struct ieee80211_tx_data tx;
2234 	struct ieee80211_sub_if_data *sdata;
2235 	struct ieee80211_if_ap *bss = NULL;
2236 	struct beacon_data *beacon;
2237 	struct ieee80211_tx_info *info;
2238 
2239 	sdata = vif_to_sdata(vif);
2240 	bss = &sdata->u.ap;
2241 
2242 	rcu_read_lock();
2243 	beacon = rcu_dereference(bss->beacon);
2244 
2245 	if (sdata->vif.type != NL80211_IFTYPE_AP || !beacon || !beacon->head)
2246 		goto out;
2247 
2248 	if (bss->dtim_count != 0)
2249 		goto out; /* send buffered bc/mc only after DTIM beacon */
2250 
2251 	while (1) {
2252 		skb = skb_dequeue(&bss->ps_bc_buf);
2253 		if (!skb)
2254 			goto out;
2255 		local->total_ps_buffered--;
2256 
2257 		if (!skb_queue_empty(&bss->ps_bc_buf) && skb->len >= 2) {
2258 			struct ieee80211_hdr *hdr =
2259 				(struct ieee80211_hdr *) skb->data;
2260 			/* more buffered multicast/broadcast frames ==> set
2261 			 * MoreData flag in IEEE 802.11 header to inform PS
2262 			 * STAs */
2263 			hdr->frame_control |=
2264 				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
2265 		}
2266 
2267 		if (!ieee80211_tx_prepare(sdata, &tx, skb))
2268 			break;
2269 		dev_kfree_skb_any(skb);
2270 	}
2271 
2272 	info = IEEE80211_SKB_CB(skb);
2273 
2274 	sta = tx.sta;
2275 	tx.flags |= IEEE80211_TX_PS_BUFFERED;
2276 	tx.channel = local->hw.conf.channel;
2277 	info->band = tx.channel->band;
2278 
2279 	if (invoke_tx_handlers(&tx))
2280 		skb = NULL;
2281  out:
2282 	rcu_read_unlock();
2283 
2284 	return skb;
2285 }
2286 EXPORT_SYMBOL(ieee80211_get_buffered_bc);
2287 
2288 void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
2289 {
2290 	skb_set_mac_header(skb, 0);
2291 	skb_set_network_header(skb, 0);
2292 	skb_set_transport_header(skb, 0);
2293 
2294 	/* send all internal mgmt frames on VO */
2295 	skb_set_queue_mapping(skb, 0);
2296 
2297 	/*
2298 	 * The other path calling ieee80211_xmit is from the tasklet,
2299 	 * and while we can handle concurrent transmissions locking
2300 	 * requirements are that we do not come into tx with bhs on.
2301 	 */
2302 	local_bh_disable();
2303 	ieee80211_xmit(sdata, skb);
2304 	local_bh_enable();
2305 }
2306