xref: /openbmc/linux/net/mac80211/tx.c (revision 643d1f7f)
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 "ieee80211_led.h"
29 #include "wep.h"
30 #include "wpa.h"
31 #include "wme.h"
32 #include "ieee80211_rate.h"
33 
34 #define IEEE80211_TX_OK		0
35 #define IEEE80211_TX_AGAIN	1
36 #define IEEE80211_TX_FRAG_AGAIN	2
37 
38 /* misc utils */
39 
40 static inline void ieee80211_include_sequence(struct ieee80211_sub_if_data *sdata,
41 					      struct ieee80211_hdr *hdr)
42 {
43 	/* Set the sequence number for this frame. */
44 	hdr->seq_ctrl = cpu_to_le16(sdata->sequence);
45 
46 	/* Increase the sequence number. */
47 	sdata->sequence = (sdata->sequence + 0x10) & IEEE80211_SCTL_SEQ;
48 }
49 
50 #ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP
51 static void ieee80211_dump_frame(const char *ifname, const char *title,
52 				 const struct sk_buff *skb)
53 {
54 	const struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
55 	u16 fc;
56 	int hdrlen;
57 	DECLARE_MAC_BUF(mac);
58 
59 	printk(KERN_DEBUG "%s: %s (len=%d)", ifname, title, skb->len);
60 	if (skb->len < 4) {
61 		printk("\n");
62 		return;
63 	}
64 
65 	fc = le16_to_cpu(hdr->frame_control);
66 	hdrlen = ieee80211_get_hdrlen(fc);
67 	if (hdrlen > skb->len)
68 		hdrlen = skb->len;
69 	if (hdrlen >= 4)
70 		printk(" FC=0x%04x DUR=0x%04x",
71 		       fc, le16_to_cpu(hdr->duration_id));
72 	if (hdrlen >= 10)
73 		printk(" A1=%s", print_mac(mac, hdr->addr1));
74 	if (hdrlen >= 16)
75 		printk(" A2=%s", print_mac(mac, hdr->addr2));
76 	if (hdrlen >= 24)
77 		printk(" A3=%s", print_mac(mac, hdr->addr3));
78 	if (hdrlen >= 30)
79 		printk(" A4=%s", print_mac(mac, hdr->addr4));
80 	printk("\n");
81 }
82 #else /* CONFIG_MAC80211_LOWTX_FRAME_DUMP */
83 static inline void ieee80211_dump_frame(const char *ifname, const char *title,
84 					struct sk_buff *skb)
85 {
86 }
87 #endif /* CONFIG_MAC80211_LOWTX_FRAME_DUMP */
88 
89 static u16 ieee80211_duration(struct ieee80211_txrx_data *tx, int group_addr,
90 			      int next_frag_len)
91 {
92 	int rate, mrate, erp, dur, i;
93 	struct ieee80211_rate *txrate = tx->u.tx.rate;
94 	struct ieee80211_local *local = tx->local;
95 	struct ieee80211_hw_mode *mode = tx->u.tx.mode;
96 
97 	erp = txrate->flags & IEEE80211_RATE_ERP;
98 
99 	/*
100 	 * data and mgmt (except PS Poll):
101 	 * - during CFP: 32768
102 	 * - during contention period:
103 	 *   if addr1 is group address: 0
104 	 *   if more fragments = 0 and addr1 is individual address: time to
105 	 *      transmit one ACK plus SIFS
106 	 *   if more fragments = 1 and addr1 is individual address: time to
107 	 *      transmit next fragment plus 2 x ACK plus 3 x SIFS
108 	 *
109 	 * IEEE 802.11, 9.6:
110 	 * - control response frame (CTS or ACK) shall be transmitted using the
111 	 *   same rate as the immediately previous frame in the frame exchange
112 	 *   sequence, if this rate belongs to the PHY mandatory rates, or else
113 	 *   at the highest possible rate belonging to the PHY rates in the
114 	 *   BSSBasicRateSet
115 	 */
116 
117 	if ((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_CTL) {
118 		/* TODO: These control frames are not currently sent by
119 		 * 80211.o, but should they be implemented, this function
120 		 * needs to be updated to support duration field calculation.
121 		 *
122 		 * RTS: time needed to transmit pending data/mgmt frame plus
123 		 *    one CTS frame plus one ACK frame plus 3 x SIFS
124 		 * CTS: duration of immediately previous RTS minus time
125 		 *    required to transmit CTS and its SIFS
126 		 * ACK: 0 if immediately previous directed data/mgmt had
127 		 *    more=0, with more=1 duration in ACK frame is duration
128 		 *    from previous frame minus time needed to transmit ACK
129 		 *    and its SIFS
130 		 * PS Poll: BIT(15) | BIT(14) | aid
131 		 */
132 		return 0;
133 	}
134 
135 	/* data/mgmt */
136 	if (0 /* FIX: data/mgmt during CFP */)
137 		return 32768;
138 
139 	if (group_addr) /* Group address as the destination - no ACK */
140 		return 0;
141 
142 	/* Individual destination address:
143 	 * IEEE 802.11, Ch. 9.6 (after IEEE 802.11g changes)
144 	 * CTS and ACK frames shall be transmitted using the highest rate in
145 	 * basic rate set that is less than or equal to the rate of the
146 	 * immediately previous frame and that is using the same modulation
147 	 * (CCK or OFDM). If no basic rate set matches with these requirements,
148 	 * the highest mandatory rate of the PHY that is less than or equal to
149 	 * the rate of the previous frame is used.
150 	 * Mandatory rates for IEEE 802.11g PHY: 1, 2, 5.5, 11, 6, 12, 24 Mbps
151 	 */
152 	rate = -1;
153 	mrate = 10; /* use 1 Mbps if everything fails */
154 	for (i = 0; i < mode->num_rates; i++) {
155 		struct ieee80211_rate *r = &mode->rates[i];
156 		if (r->rate > txrate->rate)
157 			break;
158 
159 		if (IEEE80211_RATE_MODULATION(txrate->flags) !=
160 		    IEEE80211_RATE_MODULATION(r->flags))
161 			continue;
162 
163 		if (r->flags & IEEE80211_RATE_BASIC)
164 			rate = r->rate;
165 		else if (r->flags & IEEE80211_RATE_MANDATORY)
166 			mrate = r->rate;
167 	}
168 	if (rate == -1) {
169 		/* No matching basic rate found; use highest suitable mandatory
170 		 * PHY rate */
171 		rate = mrate;
172 	}
173 
174 	/* Time needed to transmit ACK
175 	 * (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up
176 	 * to closest integer */
177 
178 	dur = ieee80211_frame_duration(local, 10, rate, erp,
179 				tx->sdata->bss_conf.use_short_preamble);
180 
181 	if (next_frag_len) {
182 		/* Frame is fragmented: duration increases with time needed to
183 		 * transmit next fragment plus ACK and 2 x SIFS. */
184 		dur *= 2; /* ACK + SIFS */
185 		/* next fragment */
186 		dur += ieee80211_frame_duration(local, next_frag_len,
187 				txrate->rate, erp,
188 				tx->sdata->bss_conf.use_short_preamble);
189 	}
190 
191 	return dur;
192 }
193 
194 static inline int __ieee80211_queue_stopped(const struct ieee80211_local *local,
195 					    int queue)
196 {
197 	return test_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
198 }
199 
200 static inline int __ieee80211_queue_pending(const struct ieee80211_local *local,
201 					    int queue)
202 {
203 	return test_bit(IEEE80211_LINK_STATE_PENDING, &local->state[queue]);
204 }
205 
206 static int inline is_ieee80211_device(struct net_device *dev,
207 				      struct net_device *master)
208 {
209 	return (wdev_priv(dev->ieee80211_ptr) ==
210 		wdev_priv(master->ieee80211_ptr));
211 }
212 
213 /* tx handlers */
214 
215 static ieee80211_txrx_result
216 ieee80211_tx_h_check_assoc(struct ieee80211_txrx_data *tx)
217 {
218 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
219 	struct sk_buff *skb = tx->skb;
220 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
221 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
222 	u32 sta_flags;
223 
224 	if (unlikely(tx->flags & IEEE80211_TXRXD_TX_INJECTED))
225 		return TXRX_CONTINUE;
226 
227 	if (unlikely(tx->local->sta_sw_scanning) &&
228 	    ((tx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_MGMT ||
229 	     (tx->fc & IEEE80211_FCTL_STYPE) != IEEE80211_STYPE_PROBE_REQ))
230 		return TXRX_DROP;
231 
232 	if (tx->flags & IEEE80211_TXRXD_TXPS_BUFFERED)
233 		return TXRX_CONTINUE;
234 
235 	sta_flags = tx->sta ? tx->sta->flags : 0;
236 
237 	if (likely(tx->flags & IEEE80211_TXRXD_TXUNICAST)) {
238 		if (unlikely(!(sta_flags & WLAN_STA_ASSOC) &&
239 			     tx->sdata->vif.type != IEEE80211_IF_TYPE_IBSS &&
240 			     (tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA)) {
241 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
242 			DECLARE_MAC_BUF(mac);
243 			printk(KERN_DEBUG "%s: dropped data frame to not "
244 			       "associated station %s\n",
245 			       tx->dev->name, print_mac(mac, hdr->addr1));
246 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
247 			I802_DEBUG_INC(tx->local->tx_handlers_drop_not_assoc);
248 			return TXRX_DROP;
249 		}
250 	} else {
251 		if (unlikely((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
252 			     tx->local->num_sta == 0 &&
253 			     tx->sdata->vif.type != IEEE80211_IF_TYPE_IBSS)) {
254 			/*
255 			 * No associated STAs - no need to send multicast
256 			 * frames.
257 			 */
258 			return TXRX_DROP;
259 		}
260 		return TXRX_CONTINUE;
261 	}
262 
263 	return TXRX_CONTINUE;
264 }
265 
266 static ieee80211_txrx_result
267 ieee80211_tx_h_sequence(struct ieee80211_txrx_data *tx)
268 {
269 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
270 
271 	if (ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control)) >= 24)
272 		ieee80211_include_sequence(tx->sdata, hdr);
273 
274 	return TXRX_CONTINUE;
275 }
276 
277 /* This function is called whenever the AP is about to exceed the maximum limit
278  * of buffered frames for power saving STAs. This situation should not really
279  * happen often during normal operation, so dropping the oldest buffered packet
280  * from each queue should be OK to make some room for new frames. */
281 static void purge_old_ps_buffers(struct ieee80211_local *local)
282 {
283 	int total = 0, purged = 0;
284 	struct sk_buff *skb;
285 	struct ieee80211_sub_if_data *sdata;
286 	struct sta_info *sta;
287 
288 	/*
289 	 * virtual interfaces are protected by RCU
290 	 */
291 	rcu_read_lock();
292 
293 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
294 		struct ieee80211_if_ap *ap;
295 		if (sdata->dev == local->mdev ||
296 		    sdata->vif.type != IEEE80211_IF_TYPE_AP)
297 			continue;
298 		ap = &sdata->u.ap;
299 		skb = skb_dequeue(&ap->ps_bc_buf);
300 		if (skb) {
301 			purged++;
302 			dev_kfree_skb(skb);
303 		}
304 		total += skb_queue_len(&ap->ps_bc_buf);
305 	}
306 	rcu_read_unlock();
307 
308 	read_lock_bh(&local->sta_lock);
309 	list_for_each_entry(sta, &local->sta_list, list) {
310 		skb = skb_dequeue(&sta->ps_tx_buf);
311 		if (skb) {
312 			purged++;
313 			dev_kfree_skb(skb);
314 		}
315 		total += skb_queue_len(&sta->ps_tx_buf);
316 	}
317 	read_unlock_bh(&local->sta_lock);
318 
319 	local->total_ps_buffered = total;
320 	printk(KERN_DEBUG "%s: PS buffers full - purged %d frames\n",
321 	       wiphy_name(local->hw.wiphy), purged);
322 }
323 
324 static ieee80211_txrx_result
325 ieee80211_tx_h_multicast_ps_buf(struct ieee80211_txrx_data *tx)
326 {
327 	/*
328 	 * broadcast/multicast frame
329 	 *
330 	 * If any of the associated stations is in power save mode,
331 	 * the frame is buffered to be sent after DTIM beacon frame.
332 	 * This is done either by the hardware or us.
333 	 */
334 
335 	/* not AP/IBSS or ordered frame */
336 	if (!tx->sdata->bss || (tx->fc & IEEE80211_FCTL_ORDER))
337 		return TXRX_CONTINUE;
338 
339 	/* no stations in PS mode */
340 	if (!atomic_read(&tx->sdata->bss->num_sta_ps))
341 		return TXRX_CONTINUE;
342 
343 	/* buffered in mac80211 */
344 	if (tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING) {
345 		if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
346 			purge_old_ps_buffers(tx->local);
347 		if (skb_queue_len(&tx->sdata->bss->ps_bc_buf) >=
348 		    AP_MAX_BC_BUFFER) {
349 			if (net_ratelimit()) {
350 				printk(KERN_DEBUG "%s: BC TX buffer full - "
351 				       "dropping the oldest frame\n",
352 				       tx->dev->name);
353 			}
354 			dev_kfree_skb(skb_dequeue(&tx->sdata->bss->ps_bc_buf));
355 		} else
356 			tx->local->total_ps_buffered++;
357 		skb_queue_tail(&tx->sdata->bss->ps_bc_buf, tx->skb);
358 		return TXRX_QUEUED;
359 	}
360 
361 	/* buffered in hardware */
362 	tx->u.tx.control->flags |= IEEE80211_TXCTL_SEND_AFTER_DTIM;
363 
364 	return TXRX_CONTINUE;
365 }
366 
367 static ieee80211_txrx_result
368 ieee80211_tx_h_unicast_ps_buf(struct ieee80211_txrx_data *tx)
369 {
370 	struct sta_info *sta = tx->sta;
371 	DECLARE_MAC_BUF(mac);
372 
373 	if (unlikely(!sta ||
374 		     ((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_MGMT &&
375 		      (tx->fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PROBE_RESP)))
376 		return TXRX_CONTINUE;
377 
378 	if (unlikely((sta->flags & WLAN_STA_PS) && !sta->pspoll)) {
379 		struct ieee80211_tx_packet_data *pkt_data;
380 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
381 		printk(KERN_DEBUG "STA %s aid %d: PS buffer (entries "
382 		       "before %d)\n",
383 		       print_mac(mac, sta->addr), sta->aid,
384 		       skb_queue_len(&sta->ps_tx_buf));
385 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
386 		sta->flags |= WLAN_STA_TIM;
387 		if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
388 			purge_old_ps_buffers(tx->local);
389 		if (skb_queue_len(&sta->ps_tx_buf) >= STA_MAX_TX_BUFFER) {
390 			struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf);
391 			if (net_ratelimit()) {
392 				printk(KERN_DEBUG "%s: STA %s TX "
393 				       "buffer full - dropping oldest frame\n",
394 				       tx->dev->name, print_mac(mac, sta->addr));
395 			}
396 			dev_kfree_skb(old);
397 		} else
398 			tx->local->total_ps_buffered++;
399 		/* Queue frame to be sent after STA sends an PS Poll frame */
400 		if (skb_queue_empty(&sta->ps_tx_buf)) {
401 			if (tx->local->ops->set_tim)
402 				tx->local->ops->set_tim(local_to_hw(tx->local),
403 						       sta->aid, 1);
404 			if (tx->sdata->bss)
405 				bss_tim_set(tx->local, tx->sdata->bss, sta->aid);
406 		}
407 		pkt_data = (struct ieee80211_tx_packet_data *)tx->skb->cb;
408 		pkt_data->jiffies = jiffies;
409 		skb_queue_tail(&sta->ps_tx_buf, tx->skb);
410 		return TXRX_QUEUED;
411 	}
412 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
413 	else if (unlikely(sta->flags & WLAN_STA_PS)) {
414 		printk(KERN_DEBUG "%s: STA %s in PS mode, but pspoll "
415 		       "set -> send frame\n", tx->dev->name,
416 		       print_mac(mac, sta->addr));
417 	}
418 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
419 	sta->pspoll = 0;
420 
421 	return TXRX_CONTINUE;
422 }
423 
424 static ieee80211_txrx_result
425 ieee80211_tx_h_ps_buf(struct ieee80211_txrx_data *tx)
426 {
427 	if (unlikely(tx->flags & IEEE80211_TXRXD_TXPS_BUFFERED))
428 		return TXRX_CONTINUE;
429 
430 	if (tx->flags & IEEE80211_TXRXD_TXUNICAST)
431 		return ieee80211_tx_h_unicast_ps_buf(tx);
432 	else
433 		return ieee80211_tx_h_multicast_ps_buf(tx);
434 }
435 
436 static ieee80211_txrx_result
437 ieee80211_tx_h_select_key(struct ieee80211_txrx_data *tx)
438 {
439 	struct ieee80211_key *key;
440 	u16 fc = tx->fc;
441 
442 	if (unlikely(tx->u.tx.control->flags & IEEE80211_TXCTL_DO_NOT_ENCRYPT))
443 		tx->key = NULL;
444 	else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
445 		tx->key = key;
446 	else if ((key = rcu_dereference(tx->sdata->default_key)))
447 		tx->key = key;
448 	else if (tx->sdata->drop_unencrypted &&
449 		 !(tx->u.tx.control->flags & IEEE80211_TXCTL_EAPOL_FRAME) &&
450 		 !(tx->flags & IEEE80211_TXRXD_TX_INJECTED)) {
451 		I802_DEBUG_INC(tx->local->tx_handlers_drop_unencrypted);
452 		return TXRX_DROP;
453 	} else
454 		tx->key = NULL;
455 
456 	if (tx->key) {
457 		u16 ftype, stype;
458 
459 		tx->key->tx_rx_count++;
460 		/* TODO: add threshold stuff again */
461 
462 		switch (tx->key->conf.alg) {
463 		case ALG_WEP:
464 			ftype = fc & IEEE80211_FCTL_FTYPE;
465 			stype = fc & IEEE80211_FCTL_STYPE;
466 
467 			if (ftype == IEEE80211_FTYPE_MGMT &&
468 			    stype == IEEE80211_STYPE_AUTH)
469 				break;
470 		case ALG_TKIP:
471 		case ALG_CCMP:
472 			if (!WLAN_FC_DATA_PRESENT(fc))
473 				tx->key = NULL;
474 			break;
475 		}
476 	}
477 
478 	if (!tx->key || !(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
479 		tx->u.tx.control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
480 
481 	return TXRX_CONTINUE;
482 }
483 
484 static ieee80211_txrx_result
485 ieee80211_tx_h_fragment(struct ieee80211_txrx_data *tx)
486 {
487 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
488 	size_t hdrlen, per_fragm, num_fragm, payload_len, left;
489 	struct sk_buff **frags, *first, *frag;
490 	int i;
491 	u16 seq;
492 	u8 *pos;
493 	int frag_threshold = tx->local->fragmentation_threshold;
494 
495 	if (!(tx->flags & IEEE80211_TXRXD_FRAGMENTED))
496 		return TXRX_CONTINUE;
497 
498 	first = tx->skb;
499 
500 	hdrlen = ieee80211_get_hdrlen(tx->fc);
501 	payload_len = first->len - hdrlen;
502 	per_fragm = frag_threshold - hdrlen - FCS_LEN;
503 	num_fragm = DIV_ROUND_UP(payload_len, per_fragm);
504 
505 	frags = kzalloc(num_fragm * sizeof(struct sk_buff *), GFP_ATOMIC);
506 	if (!frags)
507 		goto fail;
508 
509 	hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
510 	seq = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_SEQ;
511 	pos = first->data + hdrlen + per_fragm;
512 	left = payload_len - per_fragm;
513 	for (i = 0; i < num_fragm - 1; i++) {
514 		struct ieee80211_hdr *fhdr;
515 		size_t copylen;
516 
517 		if (left <= 0)
518 			goto fail;
519 
520 		/* reserve enough extra head and tail room for possible
521 		 * encryption */
522 		frag = frags[i] =
523 			dev_alloc_skb(tx->local->tx_headroom +
524 				      frag_threshold +
525 				      IEEE80211_ENCRYPT_HEADROOM +
526 				      IEEE80211_ENCRYPT_TAILROOM);
527 		if (!frag)
528 			goto fail;
529 		/* Make sure that all fragments use the same priority so
530 		 * that they end up using the same TX queue */
531 		frag->priority = first->priority;
532 		skb_reserve(frag, tx->local->tx_headroom +
533 				  IEEE80211_ENCRYPT_HEADROOM);
534 		fhdr = (struct ieee80211_hdr *) skb_put(frag, hdrlen);
535 		memcpy(fhdr, first->data, hdrlen);
536 		if (i == num_fragm - 2)
537 			fhdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREFRAGS);
538 		fhdr->seq_ctrl = cpu_to_le16(seq | ((i + 1) & IEEE80211_SCTL_FRAG));
539 		copylen = left > per_fragm ? per_fragm : left;
540 		memcpy(skb_put(frag, copylen), pos, copylen);
541 
542 		pos += copylen;
543 		left -= copylen;
544 	}
545 	skb_trim(first, hdrlen + per_fragm);
546 
547 	tx->u.tx.num_extra_frag = num_fragm - 1;
548 	tx->u.tx.extra_frag = frags;
549 
550 	return TXRX_CONTINUE;
551 
552  fail:
553 	printk(KERN_DEBUG "%s: failed to fragment frame\n", tx->dev->name);
554 	if (frags) {
555 		for (i = 0; i < num_fragm - 1; i++)
556 			if (frags[i])
557 				dev_kfree_skb(frags[i]);
558 		kfree(frags);
559 	}
560 	I802_DEBUG_INC(tx->local->tx_handlers_drop_fragment);
561 	return TXRX_DROP;
562 }
563 
564 static ieee80211_txrx_result
565 ieee80211_tx_h_encrypt(struct ieee80211_txrx_data *tx)
566 {
567 	if (!tx->key)
568 		return TXRX_CONTINUE;
569 
570 	switch (tx->key->conf.alg) {
571 	case ALG_WEP:
572 		return ieee80211_crypto_wep_encrypt(tx);
573 	case ALG_TKIP:
574 		return ieee80211_crypto_tkip_encrypt(tx);
575 	case ALG_CCMP:
576 		return ieee80211_crypto_ccmp_encrypt(tx);
577 	}
578 
579 	/* not reached */
580 	WARN_ON(1);
581 	return TXRX_DROP;
582 }
583 
584 static ieee80211_txrx_result
585 ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
586 {
587 	struct rate_selection rsel;
588 
589 	if (likely(!tx->u.tx.rate)) {
590 		rate_control_get_rate(tx->dev, tx->u.tx.mode, tx->skb, &rsel);
591 		tx->u.tx.rate = rsel.rate;
592 		if (unlikely(rsel.probe != NULL)) {
593 			tx->u.tx.control->flags |=
594 				IEEE80211_TXCTL_RATE_CTRL_PROBE;
595 			tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
596 			tx->u.tx.control->alt_retry_rate = tx->u.tx.rate->val;
597 			tx->u.tx.rate = rsel.probe;
598 		} else
599 			tx->u.tx.control->alt_retry_rate = -1;
600 
601 		if (!tx->u.tx.rate)
602 			return TXRX_DROP;
603 	} else
604 		tx->u.tx.control->alt_retry_rate = -1;
605 
606 	if (tx->u.tx.mode->mode == MODE_IEEE80211G &&
607 	    tx->sdata->bss_conf.use_cts_prot &&
608 	    (tx->flags & IEEE80211_TXRXD_FRAGMENTED) && rsel.nonerp) {
609 		tx->u.tx.last_frag_rate = tx->u.tx.rate;
610 		if (rsel.probe)
611 			tx->flags &= ~IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
612 		else
613 			tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
614 		tx->u.tx.rate = rsel.nonerp;
615 		tx->u.tx.control->rate = rsel.nonerp;
616 		tx->u.tx.control->flags &= ~IEEE80211_TXCTL_RATE_CTRL_PROBE;
617 	} else {
618 		tx->u.tx.last_frag_rate = tx->u.tx.rate;
619 		tx->u.tx.control->rate = tx->u.tx.rate;
620 	}
621 	tx->u.tx.control->tx_rate = tx->u.tx.rate->val;
622 
623 	return TXRX_CONTINUE;
624 }
625 
626 static ieee80211_txrx_result
627 ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx)
628 {
629 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
630 	u16 fc = le16_to_cpu(hdr->frame_control);
631 	u16 dur;
632 	struct ieee80211_tx_control *control = tx->u.tx.control;
633 	struct ieee80211_hw_mode *mode = tx->u.tx.mode;
634 
635 	if (!control->retry_limit) {
636 		if (!is_multicast_ether_addr(hdr->addr1)) {
637 			if (tx->skb->len + FCS_LEN > tx->local->rts_threshold
638 			    && tx->local->rts_threshold <
639 					IEEE80211_MAX_RTS_THRESHOLD) {
640 				control->flags |=
641 					IEEE80211_TXCTL_USE_RTS_CTS;
642 				control->flags |=
643 					IEEE80211_TXCTL_LONG_RETRY_LIMIT;
644 				control->retry_limit =
645 					tx->local->long_retry_limit;
646 			} else {
647 				control->retry_limit =
648 					tx->local->short_retry_limit;
649 			}
650 		} else {
651 			control->retry_limit = 1;
652 		}
653 	}
654 
655 	if (tx->flags & IEEE80211_TXRXD_FRAGMENTED) {
656 		/* Do not use multiple retry rates when sending fragmented
657 		 * frames.
658 		 * TODO: The last fragment could still use multiple retry
659 		 * rates. */
660 		control->alt_retry_rate = -1;
661 	}
662 
663 	/* Use CTS protection for unicast frames sent using extended rates if
664 	 * there are associated non-ERP stations and RTS/CTS is not configured
665 	 * for the frame. */
666 	if (mode->mode == MODE_IEEE80211G &&
667 	    (tx->u.tx.rate->flags & IEEE80211_RATE_ERP) &&
668 	    (tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
669 	    tx->sdata->bss_conf.use_cts_prot &&
670 	    !(control->flags & IEEE80211_TXCTL_USE_RTS_CTS))
671 		control->flags |= IEEE80211_TXCTL_USE_CTS_PROTECT;
672 
673 	/* Transmit data frames using short preambles if the driver supports
674 	 * short preambles at the selected rate and short preambles are
675 	 * available on the network at the current point in time. */
676 	if (((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA) &&
677 	    (tx->u.tx.rate->flags & IEEE80211_RATE_PREAMBLE2) &&
678 	    tx->sdata->bss_conf.use_short_preamble &&
679 	    (!tx->sta || (tx->sta->flags & WLAN_STA_SHORT_PREAMBLE))) {
680 		tx->u.tx.control->tx_rate = tx->u.tx.rate->val2;
681 	}
682 
683 	/* Setup duration field for the first fragment of the frame. Duration
684 	 * for remaining fragments will be updated when they are being sent
685 	 * to low-level driver in ieee80211_tx(). */
686 	dur = ieee80211_duration(tx, is_multicast_ether_addr(hdr->addr1),
687 				 (tx->flags & IEEE80211_TXRXD_FRAGMENTED) ?
688 				 tx->u.tx.extra_frag[0]->len : 0);
689 	hdr->duration_id = cpu_to_le16(dur);
690 
691 	if ((control->flags & IEEE80211_TXCTL_USE_RTS_CTS) ||
692 	    (control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)) {
693 		struct ieee80211_rate *rate;
694 
695 		/* Do not use multiple retry rates when using RTS/CTS */
696 		control->alt_retry_rate = -1;
697 
698 		/* Use min(data rate, max base rate) as CTS/RTS rate */
699 		rate = tx->u.tx.rate;
700 		while (rate > mode->rates &&
701 		       !(rate->flags & IEEE80211_RATE_BASIC))
702 			rate--;
703 
704 		control->rts_cts_rate = rate->val;
705 		control->rts_rate = rate;
706 	}
707 
708 	if (tx->sta) {
709 		tx->sta->tx_packets++;
710 		tx->sta->tx_fragments++;
711 		tx->sta->tx_bytes += tx->skb->len;
712 		if (tx->u.tx.extra_frag) {
713 			int i;
714 			tx->sta->tx_fragments += tx->u.tx.num_extra_frag;
715 			for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
716 				tx->sta->tx_bytes +=
717 					tx->u.tx.extra_frag[i]->len;
718 			}
719 		}
720 	}
721 
722 	return TXRX_CONTINUE;
723 }
724 
725 static ieee80211_txrx_result
726 ieee80211_tx_h_load_stats(struct ieee80211_txrx_data *tx)
727 {
728 	struct ieee80211_local *local = tx->local;
729 	struct ieee80211_hw_mode *mode = tx->u.tx.mode;
730 	struct sk_buff *skb = tx->skb;
731 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
732 	u32 load = 0, hdrtime;
733 
734 	/* TODO: this could be part of tx_status handling, so that the number
735 	 * of retries would be known; TX rate should in that case be stored
736 	 * somewhere with the packet */
737 
738 	/* Estimate total channel use caused by this frame */
739 
740 	/* 1 bit at 1 Mbit/s takes 1 usec; in channel_use values,
741 	 * 1 usec = 1/8 * (1080 / 10) = 13.5 */
742 
743 	if (mode->mode == MODE_IEEE80211A ||
744 	    (mode->mode == MODE_IEEE80211G &&
745 	     tx->u.tx.rate->flags & IEEE80211_RATE_ERP))
746 		hdrtime = CHAN_UTIL_HDR_SHORT;
747 	else
748 		hdrtime = CHAN_UTIL_HDR_LONG;
749 
750 	load = hdrtime;
751 	if (!is_multicast_ether_addr(hdr->addr1))
752 		load += hdrtime;
753 
754 	if (tx->u.tx.control->flags & IEEE80211_TXCTL_USE_RTS_CTS)
755 		load += 2 * hdrtime;
756 	else if (tx->u.tx.control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)
757 		load += hdrtime;
758 
759 	load += skb->len * tx->u.tx.rate->rate_inv;
760 
761 	if (tx->u.tx.extra_frag) {
762 		int i;
763 		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
764 			load += 2 * hdrtime;
765 			load += tx->u.tx.extra_frag[i]->len *
766 				tx->u.tx.rate->rate;
767 		}
768 	}
769 
770 	/* Divide channel_use by 8 to avoid wrapping around the counter */
771 	load >>= CHAN_UTIL_SHIFT;
772 	local->channel_use_raw += load;
773 	if (tx->sta)
774 		tx->sta->channel_use_raw += load;
775 	tx->sdata->channel_use_raw += load;
776 
777 	return TXRX_CONTINUE;
778 }
779 
780 /* TODO: implement register/unregister functions for adding TX/RX handlers
781  * into ordered list */
782 
783 ieee80211_tx_handler ieee80211_tx_handlers[] =
784 {
785 	ieee80211_tx_h_check_assoc,
786 	ieee80211_tx_h_sequence,
787 	ieee80211_tx_h_ps_buf,
788 	ieee80211_tx_h_select_key,
789 	ieee80211_tx_h_michael_mic_add,
790 	ieee80211_tx_h_fragment,
791 	ieee80211_tx_h_encrypt,
792 	ieee80211_tx_h_rate_ctrl,
793 	ieee80211_tx_h_misc,
794 	ieee80211_tx_h_load_stats,
795 	NULL
796 };
797 
798 /* actual transmit path */
799 
800 /*
801  * deal with packet injection down monitor interface
802  * with Radiotap Header -- only called for monitor mode interface
803  */
804 static ieee80211_txrx_result
805 __ieee80211_parse_tx_radiotap(struct ieee80211_txrx_data *tx,
806 			      struct sk_buff *skb)
807 {
808 	/*
809 	 * this is the moment to interpret and discard the radiotap header that
810 	 * must be at the start of the packet injected in Monitor mode
811 	 *
812 	 * Need to take some care with endian-ness since radiotap
813 	 * args are little-endian
814 	 */
815 
816 	struct ieee80211_radiotap_iterator iterator;
817 	struct ieee80211_radiotap_header *rthdr =
818 		(struct ieee80211_radiotap_header *) skb->data;
819 	struct ieee80211_hw_mode *mode = tx->local->hw.conf.mode;
820 	int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
821 	struct ieee80211_tx_control *control = tx->u.tx.control;
822 
823 	control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
824 	tx->flags |= IEEE80211_TXRXD_TX_INJECTED;
825 	tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
826 
827 	/*
828 	 * for every radiotap entry that is present
829 	 * (ieee80211_radiotap_iterator_next returns -ENOENT when no more
830 	 * entries present, or -EINVAL on error)
831 	 */
832 
833 	while (!ret) {
834 		int i, target_rate;
835 
836 		ret = ieee80211_radiotap_iterator_next(&iterator);
837 
838 		if (ret)
839 			continue;
840 
841 		/* see if this argument is something we can use */
842 		switch (iterator.this_arg_index) {
843 		/*
844 		 * You must take care when dereferencing iterator.this_arg
845 		 * for multibyte types... the pointer is not aligned.  Use
846 		 * get_unaligned((type *)iterator.this_arg) to dereference
847 		 * iterator.this_arg for type "type" safely on all arches.
848 		*/
849 		case IEEE80211_RADIOTAP_RATE:
850 			/*
851 			 * radiotap rate u8 is in 500kbps units eg, 0x02=1Mbps
852 			 * ieee80211 rate int is in 100kbps units eg, 0x0a=1Mbps
853 			 */
854 			target_rate = (*iterator.this_arg) * 5;
855 			for (i = 0; i < mode->num_rates; i++) {
856 				struct ieee80211_rate *r = &mode->rates[i];
857 
858 				if (r->rate == target_rate) {
859 					tx->u.tx.rate = r;
860 					break;
861 				}
862 			}
863 			break;
864 
865 		case IEEE80211_RADIOTAP_ANTENNA:
866 			/*
867 			 * radiotap uses 0 for 1st ant, mac80211 is 1 for
868 			 * 1st ant
869 			 */
870 			control->antenna_sel_tx = (*iterator.this_arg) + 1;
871 			break;
872 
873 		case IEEE80211_RADIOTAP_DBM_TX_POWER:
874 			control->power_level = *iterator.this_arg;
875 			break;
876 
877 		case IEEE80211_RADIOTAP_FLAGS:
878 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
879 				/*
880 				 * this indicates that the skb we have been
881 				 * handed has the 32-bit FCS CRC at the end...
882 				 * we should react to that by snipping it off
883 				 * because it will be recomputed and added
884 				 * on transmission
885 				 */
886 				if (skb->len < (iterator.max_length + FCS_LEN))
887 					return TXRX_DROP;
888 
889 				skb_trim(skb, skb->len - FCS_LEN);
890 			}
891 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
892 				control->flags &=
893 					~IEEE80211_TXCTL_DO_NOT_ENCRYPT;
894 			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
895 				tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
896 			break;
897 
898 		/*
899 		 * Please update the file
900 		 * Documentation/networking/mac80211-injection.txt
901 		 * when parsing new fields here.
902 		 */
903 
904 		default:
905 			break;
906 		}
907 	}
908 
909 	if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
910 		return TXRX_DROP;
911 
912 	/*
913 	 * remove the radiotap header
914 	 * iterator->max_length was sanity-checked against
915 	 * skb->len by iterator init
916 	 */
917 	skb_pull(skb, iterator.max_length);
918 
919 	return TXRX_CONTINUE;
920 }
921 
922 /*
923  * initialises @tx
924  */
925 static ieee80211_txrx_result
926 __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
927 		       struct sk_buff *skb,
928 		       struct net_device *dev,
929 		       struct ieee80211_tx_control *control)
930 {
931 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
932 	struct ieee80211_hdr *hdr;
933 	struct ieee80211_sub_if_data *sdata;
934 
935 	int hdrlen;
936 
937 	memset(tx, 0, sizeof(*tx));
938 	tx->skb = skb;
939 	tx->dev = dev; /* use original interface */
940 	tx->local = local;
941 	tx->sdata = IEEE80211_DEV_TO_SUB_IF(dev);
942 	tx->u.tx.control = control;
943 	/*
944 	 * Set this flag (used below to indicate "automatic fragmentation"),
945 	 * it will be cleared/left by radiotap as desired.
946 	 */
947 	tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
948 
949 	/* process and remove the injection radiotap header */
950 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
951 	if (unlikely(sdata->vif.type == IEEE80211_IF_TYPE_MNTR)) {
952 		if (__ieee80211_parse_tx_radiotap(tx, skb) == TXRX_DROP)
953 			return TXRX_DROP;
954 
955 		/*
956 		 * __ieee80211_parse_tx_radiotap has now removed
957 		 * the radiotap header that was present and pre-filled
958 		 * 'tx' with tx control information.
959 		 */
960 	}
961 
962 	hdr = (struct ieee80211_hdr *) skb->data;
963 
964 	tx->sta = sta_info_get(local, hdr->addr1);
965 	tx->fc = le16_to_cpu(hdr->frame_control);
966 
967 	if (is_multicast_ether_addr(hdr->addr1)) {
968 		tx->flags &= ~IEEE80211_TXRXD_TXUNICAST;
969 		control->flags |= IEEE80211_TXCTL_NO_ACK;
970 	} else {
971 		tx->flags |= IEEE80211_TXRXD_TXUNICAST;
972 		control->flags &= ~IEEE80211_TXCTL_NO_ACK;
973 	}
974 
975 	if (tx->flags & IEEE80211_TXRXD_FRAGMENTED) {
976 		if ((tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
977 		    skb->len + FCS_LEN > local->fragmentation_threshold &&
978 		    !local->ops->set_frag_threshold)
979 			tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
980 		else
981 			tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
982 	}
983 
984 	if (!tx->sta)
985 		control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
986 	else if (tx->sta->clear_dst_mask) {
987 		control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
988 		tx->sta->clear_dst_mask = 0;
989 	}
990 
991 	hdrlen = ieee80211_get_hdrlen(tx->fc);
992 	if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
993 		u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
994 		tx->ethertype = (pos[0] << 8) | pos[1];
995 	}
996 	control->flags |= IEEE80211_TXCTL_FIRST_FRAGMENT;
997 
998 	return TXRX_CONTINUE;
999 }
1000 
1001 /*
1002  * NB: @tx is uninitialised when passed in here
1003  */
1004 static int ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
1005 				struct sk_buff *skb,
1006 				struct net_device *mdev,
1007 				struct ieee80211_tx_control *control)
1008 {
1009 	struct ieee80211_tx_packet_data *pkt_data;
1010 	struct net_device *dev;
1011 
1012 	pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
1013 	dev = dev_get_by_index(&init_net, pkt_data->ifindex);
1014 	if (unlikely(dev && !is_ieee80211_device(dev, mdev))) {
1015 		dev_put(dev);
1016 		dev = NULL;
1017 	}
1018 	if (unlikely(!dev))
1019 		return -ENODEV;
1020 	/* initialises tx with control */
1021 	__ieee80211_tx_prepare(tx, skb, dev, control);
1022 	dev_put(dev);
1023 	return 0;
1024 }
1025 
1026 static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
1027 			  struct ieee80211_txrx_data *tx)
1028 {
1029 	struct ieee80211_tx_control *control = tx->u.tx.control;
1030 	int ret, i;
1031 
1032 	if (!ieee80211_qdisc_installed(local->mdev) &&
1033 	    __ieee80211_queue_stopped(local, 0)) {
1034 		netif_stop_queue(local->mdev);
1035 		return IEEE80211_TX_AGAIN;
1036 	}
1037 	if (skb) {
1038 		ieee80211_dump_frame(wiphy_name(local->hw.wiphy),
1039 				     "TX to low-level driver", skb);
1040 		ret = local->ops->tx(local_to_hw(local), skb, control);
1041 		if (ret)
1042 			return IEEE80211_TX_AGAIN;
1043 		local->mdev->trans_start = jiffies;
1044 		ieee80211_led_tx(local, 1);
1045 	}
1046 	if (tx->u.tx.extra_frag) {
1047 		control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS |
1048 				    IEEE80211_TXCTL_USE_CTS_PROTECT |
1049 				    IEEE80211_TXCTL_CLEAR_DST_MASK |
1050 				    IEEE80211_TXCTL_FIRST_FRAGMENT);
1051 		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
1052 			if (!tx->u.tx.extra_frag[i])
1053 				continue;
1054 			if (__ieee80211_queue_stopped(local, control->queue))
1055 				return IEEE80211_TX_FRAG_AGAIN;
1056 			if (i == tx->u.tx.num_extra_frag) {
1057 				control->tx_rate = tx->u.tx.last_frag_hwrate;
1058 				control->rate = tx->u.tx.last_frag_rate;
1059 				if (tx->flags & IEEE80211_TXRXD_TXPROBE_LAST_FRAG)
1060 					control->flags |=
1061 						IEEE80211_TXCTL_RATE_CTRL_PROBE;
1062 				else
1063 					control->flags &=
1064 						~IEEE80211_TXCTL_RATE_CTRL_PROBE;
1065 			}
1066 
1067 			ieee80211_dump_frame(wiphy_name(local->hw.wiphy),
1068 					     "TX to low-level driver",
1069 					     tx->u.tx.extra_frag[i]);
1070 			ret = local->ops->tx(local_to_hw(local),
1071 					    tx->u.tx.extra_frag[i],
1072 					    control);
1073 			if (ret)
1074 				return IEEE80211_TX_FRAG_AGAIN;
1075 			local->mdev->trans_start = jiffies;
1076 			ieee80211_led_tx(local, 1);
1077 			tx->u.tx.extra_frag[i] = NULL;
1078 		}
1079 		kfree(tx->u.tx.extra_frag);
1080 		tx->u.tx.extra_frag = NULL;
1081 	}
1082 	return IEEE80211_TX_OK;
1083 }
1084 
1085 static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
1086 			struct ieee80211_tx_control *control)
1087 {
1088 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
1089 	struct sta_info *sta;
1090 	ieee80211_tx_handler *handler;
1091 	struct ieee80211_txrx_data tx;
1092 	ieee80211_txrx_result res = TXRX_DROP, res_prepare;
1093 	int ret, i;
1094 
1095 	WARN_ON(__ieee80211_queue_pending(local, control->queue));
1096 
1097 	if (unlikely(skb->len < 10)) {
1098 		dev_kfree_skb(skb);
1099 		return 0;
1100 	}
1101 
1102 	/* initialises tx */
1103 	res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
1104 
1105 	if (res_prepare == TXRX_DROP) {
1106 		dev_kfree_skb(skb);
1107 		return 0;
1108 	}
1109 
1110 	/*
1111 	 * key references are protected using RCU and this requires that
1112 	 * we are in a read-site RCU section during receive processing
1113 	 */
1114 	rcu_read_lock();
1115 
1116 	sta = tx.sta;
1117 	tx.u.tx.mode = local->hw.conf.mode;
1118 
1119 	for (handler = local->tx_handlers; *handler != NULL;
1120 	     handler++) {
1121 		res = (*handler)(&tx);
1122 		if (res != TXRX_CONTINUE)
1123 			break;
1124 	}
1125 
1126 	skb = tx.skb; /* handlers are allowed to change skb */
1127 
1128 	if (sta)
1129 		sta_info_put(sta);
1130 
1131 	if (unlikely(res == TXRX_DROP)) {
1132 		I802_DEBUG_INC(local->tx_handlers_drop);
1133 		goto drop;
1134 	}
1135 
1136 	if (unlikely(res == TXRX_QUEUED)) {
1137 		I802_DEBUG_INC(local->tx_handlers_queued);
1138 		rcu_read_unlock();
1139 		return 0;
1140 	}
1141 
1142 	if (tx.u.tx.extra_frag) {
1143 		for (i = 0; i < tx.u.tx.num_extra_frag; i++) {
1144 			int next_len, dur;
1145 			struct ieee80211_hdr *hdr =
1146 				(struct ieee80211_hdr *)
1147 				tx.u.tx.extra_frag[i]->data;
1148 
1149 			if (i + 1 < tx.u.tx.num_extra_frag) {
1150 				next_len = tx.u.tx.extra_frag[i + 1]->len;
1151 			} else {
1152 				next_len = 0;
1153 				tx.u.tx.rate = tx.u.tx.last_frag_rate;
1154 				tx.u.tx.last_frag_hwrate = tx.u.tx.rate->val;
1155 			}
1156 			dur = ieee80211_duration(&tx, 0, next_len);
1157 			hdr->duration_id = cpu_to_le16(dur);
1158 		}
1159 	}
1160 
1161 retry:
1162 	ret = __ieee80211_tx(local, skb, &tx);
1163 	if (ret) {
1164 		struct ieee80211_tx_stored_packet *store =
1165 			&local->pending_packet[control->queue];
1166 
1167 		if (ret == IEEE80211_TX_FRAG_AGAIN)
1168 			skb = NULL;
1169 		set_bit(IEEE80211_LINK_STATE_PENDING,
1170 			&local->state[control->queue]);
1171 		smp_mb();
1172 		/* When the driver gets out of buffers during sending of
1173 		 * fragments and calls ieee80211_stop_queue, there is
1174 		 * a small window between IEEE80211_LINK_STATE_XOFF and
1175 		 * IEEE80211_LINK_STATE_PENDING flags are set. If a buffer
1176 		 * gets available in that window (i.e. driver calls
1177 		 * ieee80211_wake_queue), we would end up with ieee80211_tx
1178 		 * called with IEEE80211_LINK_STATE_PENDING. Prevent this by
1179 		 * continuing transmitting here when that situation is
1180 		 * possible to have happened. */
1181 		if (!__ieee80211_queue_stopped(local, control->queue)) {
1182 			clear_bit(IEEE80211_LINK_STATE_PENDING,
1183 				  &local->state[control->queue]);
1184 			goto retry;
1185 		}
1186 		memcpy(&store->control, control,
1187 		       sizeof(struct ieee80211_tx_control));
1188 		store->skb = skb;
1189 		store->extra_frag = tx.u.tx.extra_frag;
1190 		store->num_extra_frag = tx.u.tx.num_extra_frag;
1191 		store->last_frag_hwrate = tx.u.tx.last_frag_hwrate;
1192 		store->last_frag_rate = tx.u.tx.last_frag_rate;
1193 		store->last_frag_rate_ctrl_probe =
1194 			!!(tx.flags & IEEE80211_TXRXD_TXPROBE_LAST_FRAG);
1195 	}
1196 	rcu_read_unlock();
1197 	return 0;
1198 
1199  drop:
1200 	if (skb)
1201 		dev_kfree_skb(skb);
1202 	for (i = 0; i < tx.u.tx.num_extra_frag; i++)
1203 		if (tx.u.tx.extra_frag[i])
1204 			dev_kfree_skb(tx.u.tx.extra_frag[i]);
1205 	kfree(tx.u.tx.extra_frag);
1206 	rcu_read_unlock();
1207 	return 0;
1208 }
1209 
1210 /* device xmit handlers */
1211 
1212 int ieee80211_master_start_xmit(struct sk_buff *skb,
1213 				struct net_device *dev)
1214 {
1215 	struct ieee80211_tx_control control;
1216 	struct ieee80211_tx_packet_data *pkt_data;
1217 	struct net_device *odev = NULL;
1218 	struct ieee80211_sub_if_data *osdata;
1219 	int headroom;
1220 	int ret;
1221 
1222 	/*
1223 	 * copy control out of the skb so other people can use skb->cb
1224 	 */
1225 	pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
1226 	memset(&control, 0, sizeof(struct ieee80211_tx_control));
1227 
1228 	if (pkt_data->ifindex)
1229 		odev = dev_get_by_index(&init_net, pkt_data->ifindex);
1230 	if (unlikely(odev && !is_ieee80211_device(odev, dev))) {
1231 		dev_put(odev);
1232 		odev = NULL;
1233 	}
1234 	if (unlikely(!odev)) {
1235 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
1236 		printk(KERN_DEBUG "%s: Discarded packet with nonexistent "
1237 		       "originating device\n", dev->name);
1238 #endif
1239 		dev_kfree_skb(skb);
1240 		return 0;
1241 	}
1242 	osdata = IEEE80211_DEV_TO_SUB_IF(odev);
1243 
1244 	headroom = osdata->local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM;
1245 	if (skb_headroom(skb) < headroom) {
1246 		if (pskb_expand_head(skb, headroom, 0, GFP_ATOMIC)) {
1247 			dev_kfree_skb(skb);
1248 			dev_put(odev);
1249 			return 0;
1250 		}
1251 	}
1252 
1253 	control.vif = &osdata->vif;
1254 	control.type = osdata->vif.type;
1255 	if (pkt_data->flags & IEEE80211_TXPD_REQ_TX_STATUS)
1256 		control.flags |= IEEE80211_TXCTL_REQ_TX_STATUS;
1257 	if (pkt_data->flags & IEEE80211_TXPD_DO_NOT_ENCRYPT)
1258 		control.flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
1259 	if (pkt_data->flags & IEEE80211_TXPD_REQUEUE)
1260 		control.flags |= IEEE80211_TXCTL_REQUEUE;
1261 	if (pkt_data->flags & IEEE80211_TXPD_EAPOL_FRAME)
1262 		control.flags |= IEEE80211_TXCTL_EAPOL_FRAME;
1263 	control.queue = pkt_data->queue;
1264 
1265 	ret = ieee80211_tx(odev, skb, &control);
1266 	dev_put(odev);
1267 
1268 	return ret;
1269 }
1270 
1271 int ieee80211_monitor_start_xmit(struct sk_buff *skb,
1272 				 struct net_device *dev)
1273 {
1274 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
1275 	struct ieee80211_tx_packet_data *pkt_data;
1276 	struct ieee80211_radiotap_header *prthdr =
1277 		(struct ieee80211_radiotap_header *)skb->data;
1278 	u16 len_rthdr;
1279 
1280 	/* check for not even having the fixed radiotap header part */
1281 	if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
1282 		goto fail; /* too short to be possibly valid */
1283 
1284 	/* is it a header version we can trust to find length from? */
1285 	if (unlikely(prthdr->it_version))
1286 		goto fail; /* only version 0 is supported */
1287 
1288 	/* then there must be a radiotap header with a length we can use */
1289 	len_rthdr = ieee80211_get_radiotap_len(skb->data);
1290 
1291 	/* does the skb contain enough to deliver on the alleged length? */
1292 	if (unlikely(skb->len < len_rthdr))
1293 		goto fail; /* skb too short for claimed rt header extent */
1294 
1295 	skb->dev = local->mdev;
1296 
1297 	pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
1298 	memset(pkt_data, 0, sizeof(*pkt_data));
1299 	/* needed because we set skb device to master */
1300 	pkt_data->ifindex = dev->ifindex;
1301 
1302 	pkt_data->flags |= IEEE80211_TXPD_DO_NOT_ENCRYPT;
1303 
1304 	/*
1305 	 * fix up the pointers accounting for the radiotap
1306 	 * header still being in there.  We are being given
1307 	 * a precooked IEEE80211 header so no need for
1308 	 * normal processing
1309 	 */
1310 	skb_set_mac_header(skb, len_rthdr);
1311 	/*
1312 	 * these are just fixed to the end of the rt area since we
1313 	 * don't have any better information and at this point, nobody cares
1314 	 */
1315 	skb_set_network_header(skb, len_rthdr);
1316 	skb_set_transport_header(skb, len_rthdr);
1317 
1318 	/* pass the radiotap header up to the next stage intact */
1319 	dev_queue_xmit(skb);
1320 	return NETDEV_TX_OK;
1321 
1322 fail:
1323 	dev_kfree_skb(skb);
1324 	return NETDEV_TX_OK; /* meaning, we dealt with the skb */
1325 }
1326 
1327 /**
1328  * ieee80211_subif_start_xmit - netif start_xmit function for Ethernet-type
1329  * subinterfaces (wlan#, WDS, and VLAN interfaces)
1330  * @skb: packet to be sent
1331  * @dev: incoming interface
1332  *
1333  * Returns: 0 on success (and frees skb in this case) or 1 on failure (skb will
1334  * not be freed, and caller is responsible for either retrying later or freeing
1335  * skb).
1336  *
1337  * This function takes in an Ethernet header and encapsulates it with suitable
1338  * IEEE 802.11 header based on which interface the packet is coming in. The
1339  * encapsulated packet will then be passed to master interface, wlan#.11, for
1340  * transmission (through low-level driver).
1341  */
1342 int ieee80211_subif_start_xmit(struct sk_buff *skb,
1343 			       struct net_device *dev)
1344 {
1345 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
1346 	struct ieee80211_tx_packet_data *pkt_data;
1347 	struct ieee80211_sub_if_data *sdata;
1348 	int ret = 1, head_need;
1349 	u16 ethertype, hdrlen, fc;
1350 	struct ieee80211_hdr hdr;
1351 	const u8 *encaps_data;
1352 	int encaps_len, skip_header_bytes;
1353 	int nh_pos, h_pos;
1354 	struct sta_info *sta;
1355 	u32 sta_flags = 0;
1356 
1357 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
1358 	if (unlikely(skb->len < ETH_HLEN)) {
1359 		printk(KERN_DEBUG "%s: short skb (len=%d)\n",
1360 		       dev->name, skb->len);
1361 		ret = 0;
1362 		goto fail;
1363 	}
1364 
1365 	nh_pos = skb_network_header(skb) - skb->data;
1366 	h_pos = skb_transport_header(skb) - skb->data;
1367 
1368 	/* convert Ethernet header to proper 802.11 header (based on
1369 	 * operation mode) */
1370 	ethertype = (skb->data[12] << 8) | skb->data[13];
1371 	fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
1372 
1373 	switch (sdata->vif.type) {
1374 	case IEEE80211_IF_TYPE_AP:
1375 	case IEEE80211_IF_TYPE_VLAN:
1376 		fc |= IEEE80211_FCTL_FROMDS;
1377 		/* DA BSSID SA */
1378 		memcpy(hdr.addr1, skb->data, ETH_ALEN);
1379 		memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1380 		memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
1381 		hdrlen = 24;
1382 		break;
1383 	case IEEE80211_IF_TYPE_WDS:
1384 		fc |= IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS;
1385 		/* RA TA DA SA */
1386 		memcpy(hdr.addr1, sdata->u.wds.remote_addr, ETH_ALEN);
1387 		memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
1388 		memcpy(hdr.addr3, skb->data, ETH_ALEN);
1389 		memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
1390 		hdrlen = 30;
1391 		break;
1392 	case IEEE80211_IF_TYPE_STA:
1393 		fc |= IEEE80211_FCTL_TODS;
1394 		/* BSSID SA DA */
1395 		memcpy(hdr.addr1, sdata->u.sta.bssid, ETH_ALEN);
1396 		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
1397 		memcpy(hdr.addr3, skb->data, ETH_ALEN);
1398 		hdrlen = 24;
1399 		break;
1400 	case IEEE80211_IF_TYPE_IBSS:
1401 		/* DA SA BSSID */
1402 		memcpy(hdr.addr1, skb->data, ETH_ALEN);
1403 		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
1404 		memcpy(hdr.addr3, sdata->u.sta.bssid, ETH_ALEN);
1405 		hdrlen = 24;
1406 		break;
1407 	default:
1408 		ret = 0;
1409 		goto fail;
1410 	}
1411 
1412 	sta = sta_info_get(local, hdr.addr1);
1413 	if (sta) {
1414 		sta_flags = sta->flags;
1415 		sta_info_put(sta);
1416 	}
1417 
1418 	/* receiver is QoS enabled, use a QoS type frame */
1419 	if (sta_flags & WLAN_STA_WME) {
1420 		fc |= IEEE80211_STYPE_QOS_DATA;
1421 		hdrlen += 2;
1422 	}
1423 
1424 	/*
1425 	 * If port access control is enabled, drop frames to unauthorised
1426 	 * stations unless they are EAPOL frames from the local station.
1427 	 */
1428 	if (unlikely(sdata->ieee802_1x_pac &&
1429 		     !(sta_flags & WLAN_STA_AUTHORIZED) &&
1430 		     !(ethertype == ETH_P_PAE &&
1431 		       compare_ether_addr(dev->dev_addr,
1432 					  skb->data + ETH_ALEN) == 0))) {
1433 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
1434 		DECLARE_MAC_BUF(mac);
1435 
1436 		if (net_ratelimit())
1437 			printk(KERN_DEBUG "%s: dropped frame to %s"
1438 			       " (unauthorized port)\n", dev->name,
1439 			       print_mac(mac, hdr.addr1));
1440 #endif
1441 
1442 		I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);
1443 
1444 		ret = 0;
1445 		goto fail;
1446 	}
1447 
1448 	hdr.frame_control = cpu_to_le16(fc);
1449 	hdr.duration_id = 0;
1450 	hdr.seq_ctrl = 0;
1451 
1452 	skip_header_bytes = ETH_HLEN;
1453 	if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
1454 		encaps_data = bridge_tunnel_header;
1455 		encaps_len = sizeof(bridge_tunnel_header);
1456 		skip_header_bytes -= 2;
1457 	} else if (ethertype >= 0x600) {
1458 		encaps_data = rfc1042_header;
1459 		encaps_len = sizeof(rfc1042_header);
1460 		skip_header_bytes -= 2;
1461 	} else {
1462 		encaps_data = NULL;
1463 		encaps_len = 0;
1464 	}
1465 
1466 	skb_pull(skb, skip_header_bytes);
1467 	nh_pos -= skip_header_bytes;
1468 	h_pos -= skip_header_bytes;
1469 
1470 	/* TODO: implement support for fragments so that there is no need to
1471 	 * reallocate and copy payload; it might be enough to support one
1472 	 * extra fragment that would be copied in the beginning of the frame
1473 	 * data.. anyway, it would be nice to include this into skb structure
1474 	 * somehow
1475 	 *
1476 	 * There are few options for this:
1477 	 * use skb->cb as an extra space for 802.11 header
1478 	 * allocate new buffer if not enough headroom
1479 	 * make sure that there is enough headroom in every skb by increasing
1480 	 * build in headroom in __dev_alloc_skb() (linux/skbuff.h) and
1481 	 * alloc_skb() (net/core/skbuff.c)
1482 	 */
1483 	head_need = hdrlen + encaps_len + local->tx_headroom;
1484 	head_need -= skb_headroom(skb);
1485 
1486 	/* We are going to modify skb data, so make a copy of it if happens to
1487 	 * be cloned. This could happen, e.g., with Linux bridge code passing
1488 	 * us broadcast frames. */
1489 
1490 	if (head_need > 0 || skb_cloned(skb)) {
1491 #if 0
1492 		printk(KERN_DEBUG "%s: need to reallocate buffer for %d bytes "
1493 		       "of headroom\n", dev->name, head_need);
1494 #endif
1495 
1496 		if (skb_cloned(skb))
1497 			I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
1498 		else
1499 			I802_DEBUG_INC(local->tx_expand_skb_head);
1500 		/* Since we have to reallocate the buffer, make sure that there
1501 		 * is enough room for possible WEP IV/ICV and TKIP (8 bytes
1502 		 * before payload and 12 after). */
1503 		if (pskb_expand_head(skb, (head_need > 0 ? head_need + 8 : 8),
1504 				     12, GFP_ATOMIC)) {
1505 			printk(KERN_DEBUG "%s: failed to reallocate TX buffer"
1506 			       "\n", dev->name);
1507 			goto fail;
1508 		}
1509 	}
1510 
1511 	if (encaps_data) {
1512 		memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
1513 		nh_pos += encaps_len;
1514 		h_pos += encaps_len;
1515 	}
1516 
1517 	if (fc & IEEE80211_STYPE_QOS_DATA) {
1518 		__le16 *qos_control;
1519 
1520 		qos_control = (__le16*) skb_push(skb, 2);
1521 		memcpy(skb_push(skb, hdrlen - 2), &hdr, hdrlen - 2);
1522 		/*
1523 		 * Maybe we could actually set some fields here, for now just
1524 		 * initialise to zero to indicate no special operation.
1525 		 */
1526 		*qos_control = 0;
1527 	} else
1528 		memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
1529 
1530 	nh_pos += hdrlen;
1531 	h_pos += hdrlen;
1532 
1533 	pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
1534 	memset(pkt_data, 0, sizeof(struct ieee80211_tx_packet_data));
1535 	pkt_data->ifindex = dev->ifindex;
1536 	if (ethertype == ETH_P_PAE)
1537 		pkt_data->flags |= IEEE80211_TXPD_EAPOL_FRAME;
1538 
1539 	skb->dev = local->mdev;
1540 	dev->stats.tx_packets++;
1541 	dev->stats.tx_bytes += skb->len;
1542 
1543 	/* Update skb pointers to various headers since this modified frame
1544 	 * is going to go through Linux networking code that may potentially
1545 	 * need things like pointer to IP header. */
1546 	skb_set_mac_header(skb, 0);
1547 	skb_set_network_header(skb, nh_pos);
1548 	skb_set_transport_header(skb, h_pos);
1549 
1550 	dev->trans_start = jiffies;
1551 	dev_queue_xmit(skb);
1552 
1553 	return 0;
1554 
1555  fail:
1556 	if (!ret)
1557 		dev_kfree_skb(skb);
1558 
1559 	return ret;
1560 }
1561 
1562 /* helper functions for pending packets for when queues are stopped */
1563 
1564 void ieee80211_clear_tx_pending(struct ieee80211_local *local)
1565 {
1566 	int i, j;
1567 	struct ieee80211_tx_stored_packet *store;
1568 
1569 	for (i = 0; i < local->hw.queues; i++) {
1570 		if (!__ieee80211_queue_pending(local, i))
1571 			continue;
1572 		store = &local->pending_packet[i];
1573 		kfree_skb(store->skb);
1574 		for (j = 0; j < store->num_extra_frag; j++)
1575 			kfree_skb(store->extra_frag[j]);
1576 		kfree(store->extra_frag);
1577 		clear_bit(IEEE80211_LINK_STATE_PENDING, &local->state[i]);
1578 	}
1579 }
1580 
1581 void ieee80211_tx_pending(unsigned long data)
1582 {
1583 	struct ieee80211_local *local = (struct ieee80211_local *)data;
1584 	struct net_device *dev = local->mdev;
1585 	struct ieee80211_tx_stored_packet *store;
1586 	struct ieee80211_txrx_data tx;
1587 	int i, ret, reschedule = 0;
1588 
1589 	netif_tx_lock_bh(dev);
1590 	for (i = 0; i < local->hw.queues; i++) {
1591 		if (__ieee80211_queue_stopped(local, i))
1592 			continue;
1593 		if (!__ieee80211_queue_pending(local, i)) {
1594 			reschedule = 1;
1595 			continue;
1596 		}
1597 		store = &local->pending_packet[i];
1598 		tx.u.tx.control = &store->control;
1599 		tx.u.tx.extra_frag = store->extra_frag;
1600 		tx.u.tx.num_extra_frag = store->num_extra_frag;
1601 		tx.u.tx.last_frag_hwrate = store->last_frag_hwrate;
1602 		tx.u.tx.last_frag_rate = store->last_frag_rate;
1603 		tx.flags = 0;
1604 		if (store->last_frag_rate_ctrl_probe)
1605 			tx.flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
1606 		ret = __ieee80211_tx(local, store->skb, &tx);
1607 		if (ret) {
1608 			if (ret == IEEE80211_TX_FRAG_AGAIN)
1609 				store->skb = NULL;
1610 		} else {
1611 			clear_bit(IEEE80211_LINK_STATE_PENDING,
1612 				  &local->state[i]);
1613 			reschedule = 1;
1614 		}
1615 	}
1616 	netif_tx_unlock_bh(dev);
1617 	if (reschedule) {
1618 		if (!ieee80211_qdisc_installed(dev)) {
1619 			if (!__ieee80211_queue_stopped(local, 0))
1620 				netif_wake_queue(dev);
1621 		} else
1622 			netif_schedule(dev);
1623 	}
1624 }
1625 
1626 /* functions for drivers to get certain frames */
1627 
1628 static void ieee80211_beacon_add_tim(struct ieee80211_local *local,
1629 				     struct ieee80211_if_ap *bss,
1630 				     struct sk_buff *skb,
1631 				     struct beacon_data *beacon)
1632 {
1633 	u8 *pos, *tim;
1634 	int aid0 = 0;
1635 	int i, have_bits = 0, n1, n2;
1636 
1637 	/* Generate bitmap for TIM only if there are any STAs in power save
1638 	 * mode. */
1639 	read_lock_bh(&local->sta_lock);
1640 	if (atomic_read(&bss->num_sta_ps) > 0)
1641 		/* in the hope that this is faster than
1642 		 * checking byte-for-byte */
1643 		have_bits = !bitmap_empty((unsigned long*)bss->tim,
1644 					  IEEE80211_MAX_AID+1);
1645 
1646 	if (bss->dtim_count == 0)
1647 		bss->dtim_count = beacon->dtim_period - 1;
1648 	else
1649 		bss->dtim_count--;
1650 
1651 	tim = pos = (u8 *) skb_put(skb, 6);
1652 	*pos++ = WLAN_EID_TIM;
1653 	*pos++ = 4;
1654 	*pos++ = bss->dtim_count;
1655 	*pos++ = beacon->dtim_period;
1656 
1657 	if (bss->dtim_count == 0 && !skb_queue_empty(&bss->ps_bc_buf))
1658 		aid0 = 1;
1659 
1660 	if (have_bits) {
1661 		/* Find largest even number N1 so that bits numbered 1 through
1662 		 * (N1 x 8) - 1 in the bitmap are 0 and number N2 so that bits
1663 		 * (N2 + 1) x 8 through 2007 are 0. */
1664 		n1 = 0;
1665 		for (i = 0; i < IEEE80211_MAX_TIM_LEN; i++) {
1666 			if (bss->tim[i]) {
1667 				n1 = i & 0xfe;
1668 				break;
1669 			}
1670 		}
1671 		n2 = n1;
1672 		for (i = IEEE80211_MAX_TIM_LEN - 1; i >= n1; i--) {
1673 			if (bss->tim[i]) {
1674 				n2 = i;
1675 				break;
1676 			}
1677 		}
1678 
1679 		/* Bitmap control */
1680 		*pos++ = n1 | aid0;
1681 		/* Part Virt Bitmap */
1682 		memcpy(pos, bss->tim + n1, n2 - n1 + 1);
1683 
1684 		tim[1] = n2 - n1 + 4;
1685 		skb_put(skb, n2 - n1);
1686 	} else {
1687 		*pos++ = aid0; /* Bitmap control */
1688 		*pos++ = 0; /* Part Virt Bitmap */
1689 	}
1690 	read_unlock_bh(&local->sta_lock);
1691 }
1692 
1693 struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
1694 				     struct ieee80211_vif *vif,
1695 				     struct ieee80211_tx_control *control)
1696 {
1697 	struct ieee80211_local *local = hw_to_local(hw);
1698 	struct sk_buff *skb;
1699 	struct net_device *bdev;
1700 	struct ieee80211_sub_if_data *sdata = NULL;
1701 	struct ieee80211_if_ap *ap = NULL;
1702 	struct rate_selection rsel;
1703 	struct beacon_data *beacon;
1704 
1705 	rcu_read_lock();
1706 
1707 	sdata = vif_to_sdata(vif);
1708 	bdev = sdata->dev;
1709 	ap = &sdata->u.ap;
1710 
1711 	beacon = rcu_dereference(ap->beacon);
1712 
1713 	if (!ap || sdata->vif.type != IEEE80211_IF_TYPE_AP || !beacon) {
1714 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
1715 		if (net_ratelimit())
1716 			printk(KERN_DEBUG "no beacon data avail for %s\n",
1717 			       bdev->name);
1718 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
1719 		skb = NULL;
1720 		goto out;
1721 	}
1722 
1723 	/* headroom, head length, tail length and maximum TIM length */
1724 	skb = dev_alloc_skb(local->tx_headroom + beacon->head_len +
1725 			    beacon->tail_len + 256);
1726 	if (!skb)
1727 		goto out;
1728 
1729 	skb_reserve(skb, local->tx_headroom);
1730 	memcpy(skb_put(skb, beacon->head_len), beacon->head,
1731 	       beacon->head_len);
1732 
1733 	ieee80211_include_sequence(sdata, (struct ieee80211_hdr *)skb->data);
1734 
1735 	ieee80211_beacon_add_tim(local, ap, skb, beacon);
1736 
1737 	if (beacon->tail)
1738 		memcpy(skb_put(skb, beacon->tail_len), beacon->tail,
1739 		       beacon->tail_len);
1740 
1741 	if (control) {
1742 		rate_control_get_rate(local->mdev, local->oper_hw_mode, skb,
1743 				      &rsel);
1744 		if (!rsel.rate) {
1745 			if (net_ratelimit()) {
1746 				printk(KERN_DEBUG "%s: ieee80211_beacon_get: "
1747 				       "no rate found\n",
1748 				       wiphy_name(local->hw.wiphy));
1749 			}
1750 			dev_kfree_skb(skb);
1751 			skb = NULL;
1752 			goto out;
1753 		}
1754 
1755 		control->vif = vif;
1756 		control->tx_rate =
1757 			(sdata->bss_conf.use_short_preamble &&
1758 			(rsel.rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
1759 			rsel.rate->val2 : rsel.rate->val;
1760 		control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
1761 		control->power_level = local->hw.conf.power_level;
1762 		control->flags |= IEEE80211_TXCTL_NO_ACK;
1763 		control->retry_limit = 1;
1764 		control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
1765 	}
1766 
1767 	ap->num_beacons++;
1768 
1769  out:
1770 	rcu_read_unlock();
1771 	return skb;
1772 }
1773 EXPORT_SYMBOL(ieee80211_beacon_get);
1774 
1775 void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
1776 		       const void *frame, size_t frame_len,
1777 		       const struct ieee80211_tx_control *frame_txctl,
1778 		       struct ieee80211_rts *rts)
1779 {
1780 	const struct ieee80211_hdr *hdr = frame;
1781 	u16 fctl;
1782 
1783 	fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS;
1784 	rts->frame_control = cpu_to_le16(fctl);
1785 	rts->duration = ieee80211_rts_duration(hw, vif, frame_len,
1786 					       frame_txctl);
1787 	memcpy(rts->ra, hdr->addr1, sizeof(rts->ra));
1788 	memcpy(rts->ta, hdr->addr2, sizeof(rts->ta));
1789 }
1790 EXPORT_SYMBOL(ieee80211_rts_get);
1791 
1792 void ieee80211_ctstoself_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
1793 			     const void *frame, size_t frame_len,
1794 			     const struct ieee80211_tx_control *frame_txctl,
1795 			     struct ieee80211_cts *cts)
1796 {
1797 	const struct ieee80211_hdr *hdr = frame;
1798 	u16 fctl;
1799 
1800 	fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS;
1801 	cts->frame_control = cpu_to_le16(fctl);
1802 	cts->duration = ieee80211_ctstoself_duration(hw, vif,
1803 						     frame_len, frame_txctl);
1804 	memcpy(cts->ra, hdr->addr1, sizeof(cts->ra));
1805 }
1806 EXPORT_SYMBOL(ieee80211_ctstoself_get);
1807 
1808 struct sk_buff *
1809 ieee80211_get_buffered_bc(struct ieee80211_hw *hw,
1810 			  struct ieee80211_vif *vif,
1811 			  struct ieee80211_tx_control *control)
1812 {
1813 	struct ieee80211_local *local = hw_to_local(hw);
1814 	struct sk_buff *skb;
1815 	struct sta_info *sta;
1816 	ieee80211_tx_handler *handler;
1817 	struct ieee80211_txrx_data tx;
1818 	ieee80211_txrx_result res = TXRX_DROP;
1819 	struct net_device *bdev;
1820 	struct ieee80211_sub_if_data *sdata;
1821 	struct ieee80211_if_ap *bss = NULL;
1822 	struct beacon_data *beacon;
1823 
1824 	sdata = vif_to_sdata(vif);
1825 	bdev = sdata->dev;
1826 
1827 
1828 	if (!bss)
1829 		return NULL;
1830 
1831 	rcu_read_lock();
1832 	beacon = rcu_dereference(bss->beacon);
1833 
1834 	if (sdata->vif.type != IEEE80211_IF_TYPE_AP || !beacon ||
1835 	    !beacon->head) {
1836 		rcu_read_unlock();
1837 		return NULL;
1838 	}
1839 	rcu_read_unlock();
1840 
1841 	if (bss->dtim_count != 0)
1842 		return NULL; /* send buffered bc/mc only after DTIM beacon */
1843 	memset(control, 0, sizeof(*control));
1844 	while (1) {
1845 		skb = skb_dequeue(&bss->ps_bc_buf);
1846 		if (!skb)
1847 			return NULL;
1848 		local->total_ps_buffered--;
1849 
1850 		if (!skb_queue_empty(&bss->ps_bc_buf) && skb->len >= 2) {
1851 			struct ieee80211_hdr *hdr =
1852 				(struct ieee80211_hdr *) skb->data;
1853 			/* more buffered multicast/broadcast frames ==> set
1854 			 * MoreData flag in IEEE 802.11 header to inform PS
1855 			 * STAs */
1856 			hdr->frame_control |=
1857 				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
1858 		}
1859 
1860 		if (!ieee80211_tx_prepare(&tx, skb, local->mdev, control))
1861 			break;
1862 		dev_kfree_skb_any(skb);
1863 	}
1864 	sta = tx.sta;
1865 	tx.flags |= IEEE80211_TXRXD_TXPS_BUFFERED;
1866 	tx.u.tx.mode = local->hw.conf.mode;
1867 
1868 	for (handler = local->tx_handlers; *handler != NULL; handler++) {
1869 		res = (*handler)(&tx);
1870 		if (res == TXRX_DROP || res == TXRX_QUEUED)
1871 			break;
1872 	}
1873 	skb = tx.skb; /* handlers are allowed to change skb */
1874 
1875 	if (res == TXRX_DROP) {
1876 		I802_DEBUG_INC(local->tx_handlers_drop);
1877 		dev_kfree_skb(skb);
1878 		skb = NULL;
1879 	} else if (res == TXRX_QUEUED) {
1880 		I802_DEBUG_INC(local->tx_handlers_queued);
1881 		skb = NULL;
1882 	}
1883 
1884 	if (sta)
1885 		sta_info_put(sta);
1886 
1887 	return skb;
1888 }
1889 EXPORT_SYMBOL(ieee80211_get_buffered_bc);
1890