rx.c 70.8 KB
Newer Older
1 2 3 4
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
5
 * Copyright 2007-2010	Johannes Berg <johannes@sipsolutions.net>
6 7 8 9 10 11
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

12
#include <linux/jiffies.h>
13 14 15 16
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
17
#include <linux/rcupdate.h>
18 19 20 21
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>

#include "ieee80211_i.h"
22
#include "driver-ops.h"
Johannes Berg's avatar
Johannes Berg committed
23
#include "led.h"
24
#include "mesh.h"
25 26 27 28 29
#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"

30 31 32 33 34 35 36
/*
 * monitor mode reception
 *
 * This function cleans up the SKB, i.e. it removes all the stuff
 * only useful for monitoring.
 */
static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
37
					   struct sk_buff *skb)
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
{
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
			skb_trim(skb, skb->len - FCS_LEN);
		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
			skb = NULL;
		}
	}

	return skb;
}

53
static inline int should_drop_frame(struct sk_buff *skb,
54
				    int present_fcs_len)
55
{
56
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
57
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
58 59 60

	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		return 1;
61
	if (unlikely(skb->len < 16 + present_fcs_len))
62
		return 1;
63 64 65
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
66 67 68 69
		return 1;
	return 0;
}

70 71 72 73 74 75 76 77 78 79 80
static int
ieee80211_rx_radiotap_len(struct ieee80211_local *local,
			  struct ieee80211_rx_status *status)
{
	int len;

	/* always present fields */
	len = sizeof(struct ieee80211_radiotap_header) + 9;

	if (status->flag & RX_FLAG_TSFT)
		len += 8;
Johannes Berg's avatar
Johannes Berg committed
81
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
82 83 84 85 86 87 88 89 90 91
		len += 1;
	if (local->hw.flags & IEEE80211_HW_NOISE_DBM)
		len += 1;

	if (len & 1) /* padding for RX_FLAGS if necessary */
		len++;

	return len;
}

92
/*
93 94 95 96 97 98 99 100 101 102
 * ieee80211_add_rx_radiotap_header - add radiotap header
 *
 * add a radiotap header containing all the fields which the hardware provided.
 */
static void
ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
				 struct sk_buff *skb,
				 struct ieee80211_rate *rate,
				 int rtap_len)
{
103
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
104 105
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
106
	u16 rx_flags = 0;
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124

	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
	memset(rthdr, 0, rtap_len);

	/* radiotap header, set always present flags */
	rthdr->it_present =
		cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
			    (1 << IEEE80211_RADIOTAP_CHANNEL) |
			    (1 << IEEE80211_RADIOTAP_ANTENNA) |
			    (1 << IEEE80211_RADIOTAP_RX_FLAGS));
	rthdr->it_len = cpu_to_le16(rtap_len);

	pos = (unsigned char *)(rthdr+1);

	/* the order of the following fields is important */

	/* IEEE80211_RADIOTAP_TSFT */
	if (status->flag & RX_FLAG_TSFT) {
125
		put_unaligned_le64(status->mactime, pos);
126 127 128 129 130 131 132 133
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
		pos += 8;
	}

	/* IEEE80211_RADIOTAP_FLAGS */
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
		*pos |= IEEE80211_RADIOTAP_F_FCS;
Johannes Berg's avatar
Johannes Berg committed
134 135
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
136 137
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
138 139 140
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
141 142 143 144 145 146 147 148 149
	if (status->flag & RX_FLAG_HT) {
		/*
		 * TODO: add following information into radiotap header once
		 * suitable fields are defined for it:
		 * - MCS index (status->rate_idx)
		 * - HT40 (status->flag & RX_FLAG_40MHZ)
		 * - short-GI (status->flag & RX_FLAG_SHORT_GI)
		 */
		*pos = 0;
150
	} else {
151
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
152
		*pos = rate->bitrate / 5;
153
	}
154 155 156
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
157
	put_unaligned_le16(status->freq, pos);
158 159
	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
160 161
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
162 163 164
	else if (status->flag & RX_FLAG_HT)
		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
165
	else if (rate->flags & IEEE80211_RATE_ERP_G)
166 167
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
168
	else
169 170
		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
	pos += 2;

	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
		*pos = status->signal;
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
		pos++;
	}

	/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */

	/* IEEE80211_RADIOTAP_ANTENNA */
	*pos = status->antenna;
	pos++;

	/* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */

	/* IEEE80211_RADIOTAP_RX_FLAGS */
	/* ensure 2 byte alignment for the 2 byte field as required */
191
	if ((pos - (u8 *)rthdr) & 1)
192
		pos++;
Johannes Berg's avatar
Johannes Berg committed
193
	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
194 195
		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
196 197 198
	pos += 2;
}

199 200 201 202 203 204 205
/*
 * This function copies a received frame to all monitor interfaces and
 * returns a cleaned-up SKB that no longer includes the FCS nor the
 * radiotap header the driver might have added.
 */
static struct sk_buff *
ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
206
		     struct ieee80211_rate *rate)
207
{
208
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
209 210 211 212 213 214 215 216 217 218 219 220 221 222
	struct ieee80211_sub_if_data *sdata;
	int needed_headroom = 0;
	struct sk_buff *skb, *skb2;
	struct net_device *prev_dev = NULL;
	int present_fcs_len = 0;

	/*
	 * First, we may need to make a copy of the skb because
	 *  (1) we need to modify it for radiotap (if not present), and
	 *  (2) the other RX handlers will modify the skb we got.
	 *
	 * We don't need to, of course, if we aren't going to return
	 * the SKB because it has a bad FCS/PLCP checksum.
	 */
223 224 225

	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_len(local, status);
226 227 228 229 230

	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
		present_fcs_len = FCS_LEN;

	if (!local->monitors) {
231
		if (should_drop_frame(origskb, present_fcs_len)) {
232 233 234 235
			dev_kfree_skb(origskb);
			return NULL;
		}

236
		return remove_monitor_info(local, origskb);
237 238
	}

239
	if (should_drop_frame(origskb, present_fcs_len)) {
240 241 242 243 244 245 246 247 248 249 250 251
		/* only need to expand headroom if necessary */
		skb = origskb;
		origskb = NULL;

		/*
		 * This shouldn't trigger often because most devices have an
		 * RX header they pull before we get here, and that should
		 * be big enough for our radiotap information. We should
		 * probably export the length to drivers so that we can have
		 * them allocate enough headroom to start with.
		 */
		if (skb_headroom(skb) < needed_headroom &&
252
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
253 254 255 256 257 258 259 260 261 262
			dev_kfree_skb(skb);
			return NULL;
		}
	} else {
		/*
		 * Need to make a copy and possibly remove radiotap header
		 * and FCS from the original.
		 */
		skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);

263
		origskb = remove_monitor_info(local, origskb);
264 265 266 267 268

		if (!skb)
			return origskb;
	}

269 270
	/* prepend radiotap information */
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
271

272
	skb_reset_mac_header(skb);
273 274 275 276 277
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	skb->pkt_type = PACKET_OTHERHOST;
	skb->protocol = htons(ETH_P_802_2);

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
278
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
279 280
			continue;

281 282 283
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

284
		if (!ieee80211_sdata_running(sdata))
285 286
			continue;

287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
				netif_rx(skb2);
			}
		}

		prev_dev = sdata->dev;
		sdata->dev->stats.rx_packets++;
		sdata->dev->stats.rx_bytes += skb->len;
	}

	if (prev_dev) {
		skb->dev = prev_dev;
		netif_rx(skb);
	} else
		dev_kfree_skb(skb);

	return origskb;
}


310
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
311
{
312
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
313 314 315
	int tid;

	/* does the frame have a qos control field? */
316 317
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
318
		/* frame has qos control */
319 320
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
		if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
321
			rx->flags |= IEEE80211_RX_AMSDU;
322
		else
323
			rx->flags &= ~IEEE80211_RX_AMSDU;
324
	} else {
325 326 327 328 329 330 331 332 333 334 335 336
		/*
		 * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
		 *
		 *	Sequence numbers for management frames, QoS data
		 *	frames with a broadcast/multicast address in the
		 *	Address 1 field, and all non-QoS data frames sent
		 *	by QoS STAs are assigned using an additional single
		 *	modulo-4096 counter, [...]
		 *
		 * We also use that counter for non-QoS STAs.
		 */
		tid = NUM_RX_DATA_QUEUES - 1;
337
	}
338

339
	rx->queue = tid;
340 341 342
	/* Set skb->priority to 1d tag if highest order bit of TID is not set.
	 * For now, set skb->priority to 0 for other cases. */
	rx->skb->priority = (tid > 7) ? 0 : tid;
343
}
344

345 346 347 348 349 350 351 352 353 354 355
/**
 * DOC: Packet alignment
 *
 * Drivers always need to pass packets that are aligned to two-byte boundaries
 * to the stack.
 *
 * Additionally, should, if possible, align the payload data in a way that
 * guarantees that the contained IP header is aligned to a four-byte
 * boundary. In the case of regular frames, this simply means aligning the
 * payload to a four-byte boundary (because either the IP header is directly
 * contained, or IV/RFC1042 headers that have a length divisible by four are
356 357 358
 * in front of it).  If the payload data is not properly aligned and the
 * architecture doesn't support efficient unaligned operations, mac80211
 * will align the data.
359 360 361 362 363 364 365 366 367 368 369 370
 *
 * With A-MSDU frames, however, the payload data address must yield two modulo
 * four because there are 14-byte 802.3 headers within the A-MSDU frames that
 * push the IP header further back to a multiple of four again. Thankfully, the
 * specs were sane enough this time around to require padding each A-MSDU
 * subframe to a length that is a multiple of four.
 *
 * Padding like Atheros hardware adds which is inbetween the 802.11 header and
 * the payload is not supported, the driver is required to move the 802.11
 * header to be directly in front of the payload in that case.
 */
static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
371
{
372 373 374
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
375
#endif
376 377
}

378

379 380
/* rx handlers */

381
static ieee80211_rx_result debug_noinline
382
ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
383 384 385 386
{
	struct ieee80211_local *local = rx->local;
	struct sk_buff *skb = rx->skb;

387
	if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning)))
388
		return ieee80211_scan_rx(rx->sdata, skb);
Zhu Yi's avatar
Zhu Yi committed
389

390 391
	if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning) &&
		     (rx->flags & IEEE80211_RX_IN_SCAN))) {
Zhu Yi's avatar
Zhu Yi committed
392
		/* drop all the other packets during a software scan anyway */
393
		if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
Zhu Yi's avatar
Zhu Yi committed
394
			dev_kfree_skb(skb);
395
		return RX_QUEUED;
396 397
	}

398
	if (unlikely(rx->flags & IEEE80211_RX_IN_SCAN)) {
399 400
		/* scanning finished during invoking of handlers */
		I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
Johannes Berg's avatar
Johannes Berg committed
401
		return RX_DROP_UNUSABLE;
402 403
	}

404
	return RX_CONTINUE;
405 406
}

407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452

static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
		return 0;

	return ieee80211_is_robust_mgmt_frame(hdr);
}


static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
		return 0;

	return ieee80211_is_robust_mgmt_frame(hdr);
}


/* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
{
	struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
	struct ieee80211_mmie *mmie;

	if (skb->len < 24 + sizeof(*mmie) ||
	    !is_multicast_ether_addr(hdr->da))
		return -1;

	if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
		return -1; /* not a robust management frame */

	mmie = (struct ieee80211_mmie *)
		(skb->data + skb->len - sizeof(*mmie));
	if (mmie->element_id != WLAN_EID_MMIE ||
	    mmie->length != sizeof(*mmie) - 2)
		return -1;

	return le16_to_cpu(mmie->key_id);
}


453
static ieee80211_rx_result
454
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
455
{
456 457
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
	unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
458
	char *dev_addr = rx->sdata->vif.addr;
459

460
	if (ieee80211_is_data(hdr->frame_control)) {
461 462 463 464 465 466 467 468 469 470 471 472
		if (is_multicast_ether_addr(hdr->addr1)) {
			if (ieee80211_has_tods(hdr->frame_control) ||
				!ieee80211_has_fromds(hdr->frame_control))
				return RX_DROP_MONITOR;
			if (memcmp(hdr->addr3, dev_addr, ETH_ALEN) == 0)
				return RX_DROP_MONITOR;
		} else {
			if (!ieee80211_has_a4(hdr->frame_control))
				return RX_DROP_MONITOR;
			if (memcmp(hdr->addr4, dev_addr, ETH_ALEN) == 0)
				return RX_DROP_MONITOR;
		}
473 474 475 476 477 478
	}

	/* If there is not an established peer link and this is not a peer link
	 * establisment frame, beacon or probe, drop the frame.
	 */

479
	if (!rx->sta || sta_plink_state(rx->sta) != PLINK_ESTAB) {
480
		struct ieee80211_mgmt *mgmt;
481

482
		if (!ieee80211_is_mgmt(hdr->frame_control))
483 484
			return RX_DROP_MONITOR;

485
		if (ieee80211_is_action(hdr->frame_control)) {
486
			mgmt = (struct ieee80211_mgmt *)hdr;
487
			if (mgmt->u.action.category != MESH_PLINK_CATEGORY)
488 489 490 491
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

492 493 494 495 496 497 498 499 500 501 502 503 504
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
		    ieee80211_is_beacon(hdr->frame_control))
			return RX_CONTINUE;

		return RX_DROP_MONITOR;

	}

#define msh_h_get(h, l) ((struct ieee80211s_hdr *) ((u8 *)h + l))

	if (ieee80211_is_data(hdr->frame_control) &&
	    is_multicast_ether_addr(hdr->addr1) &&
505
	    mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
506
		return RX_DROP_MONITOR;
Johannes Berg's avatar
Johannes Berg committed
507
#undef msh_h_get
508

Johannes Berg's avatar
Johannes Berg committed
509 510
	return RX_CONTINUE;
}
511

512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
#define SEQ_MODULO 0x1000
#define SEQ_MASK   0xfff

static inline int seq_less(u16 sq1, u16 sq2)
{
	return ((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1);
}

static inline u16 seq_inc(u16 sq)
{
	return (sq + 1) & SEQ_MASK;
}

static inline u16 seq_sub(u16 sq1, u16 sq2)
{
	return (sq1 - sq2) & SEQ_MASK;
}


static void ieee80211_release_reorder_frame(struct ieee80211_hw *hw,
					    struct tid_ampdu_rx *tid_agg_rx,
533 534
					    int index,
					    struct sk_buff_head *frames)
535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551
{
	struct ieee80211_supported_band *sband;
	struct ieee80211_rate *rate = NULL;
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
	struct ieee80211_rx_status *status;

	if (!skb)
		goto no_frame;

	status = IEEE80211_SKB_RXCB(skb);

	/* release the reordered frames to stack */
	sband = hw->wiphy->bands[status->band];
	if (!(status->flag & RX_FLAG_HT))
		rate = &sband->bitrates[status->rate_idx];
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
552
	__skb_queue_tail(frames, skb);
553 554 555 556 557 558 559

no_frame:
	tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
}

static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw,
					     struct tid_ampdu_rx *tid_agg_rx,
560 561
					     u16 head_seq_num,
					     struct sk_buff_head *frames)
562 563 564 565 566 567
{
	int index;

	while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
		index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
568
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587
	}
}

/*
 * Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If
 * the skb was added to the buffer longer than this time ago, the earlier
 * frames that have not yet been received are assumed to be lost and the skb
 * can be released for processing. This may also release other skb's from the
 * reorder buffer if there are no additional gaps between the frames.
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

/*
 * As this function belongs to the RX path it must be under
 * rcu_read_lock protection. It returns false if the frame
 * can be processed immediately, true if it was consumed.
 */
static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
					     struct tid_ampdu_rx *tid_agg_rx,
588 589
					     struct sk_buff *skb,
					     struct sk_buff_head *frames)
590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	u16 sc = le16_to_cpu(hdr->seq_ctrl);
	u16 mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
	u16 head_seq_num, buf_size;
	int index;

	buf_size = tid_agg_rx->buf_size;
	head_seq_num = tid_agg_rx->head_seq_num;

	/* frame with out of date sequence number */
	if (seq_less(mpdu_seq_num, head_seq_num)) {
		dev_kfree_skb(skb);
		return true;
	}

	/*
	 * If frame the sequence number exceeds our buffering window
	 * size release some previous frames to make room for this one.
	 */
	if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) {
		head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size));
		/* release stored frames up to new head to stack */
613 614
		ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num,
						 frames);
615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668
	}

	/* Now the new frame is always in the range of the reordering buffer */

	index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) % tid_agg_rx->buf_size;

	/* check if we already stored this frame */
	if (tid_agg_rx->reorder_buf[index]) {
		dev_kfree_skb(skb);
		return true;
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
	 */
	if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
	    tid_agg_rx->stored_mpdu_num == 0) {
		tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
		return false;
	}

	/* put the frame in the reordering buffer */
	tid_agg_rx->reorder_buf[index] = skb;
	tid_agg_rx->reorder_time[index] = jiffies;
	tid_agg_rx->stored_mpdu_num++;
	/* release the buffer until next missing frame */
	index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
						tid_agg_rx->buf_size;
	if (!tid_agg_rx->reorder_buf[index] &&
	    tid_agg_rx->stored_mpdu_num > 1) {
		/*
		 * No buffers ready to be released, but check whether any
		 * frames in the reorder buffer have timed out.
		 */
		int j;
		int skipped = 1;
		for (j = (index + 1) % tid_agg_rx->buf_size; j != index;
		     j = (j + 1) % tid_agg_rx->buf_size) {
			if (!tid_agg_rx->reorder_buf[j]) {
				skipped++;
				continue;
			}
			if (!time_after(jiffies, tid_agg_rx->reorder_time[j] +
					HT_RX_REORDER_BUF_TIMEOUT))
				break;

#ifdef CONFIG_MAC80211_HT_DEBUG
			if (net_ratelimit())
				printk(KERN_DEBUG "%s: release an RX reorder "
				       "frame due to timeout on earlier "
				       "frames\n",
				       wiphy_name(hw->wiphy));
#endif
669 670
			ieee80211_release_reorder_frame(hw, tid_agg_rx,
							j, frames);
671 672 673 674 675 676 677 678 679

			/*
			 * Increment the head seq# also for the skipped slots.
			 */
			tid_agg_rx->head_seq_num =
				(tid_agg_rx->head_seq_num + skipped) & SEQ_MASK;
			skipped = 0;
		}
	} else while (tid_agg_rx->reorder_buf[index]) {
680
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
681 682 683 684 685 686 687 688 689 690 691
		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}

	return true;
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
692 693
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
				       struct sk_buff_head *frames)
694
{
695 696
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
697 698
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
699
	struct sta_info *sta = rx->sta;
700 701 702 703 704
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
	int tid;

	if (!ieee80211_is_data_qos(hdr->frame_control))
705
		goto dont_reorder;
706 707 708 709 710 711 712

	/*
	 * filter the QoS data rx stream according to
	 * STA/TID and check if this STA/TID is on aggregation
	 */

	if (!sta)
713
		goto dont_reorder;
714 715 716 717

	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

	if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL)
718
		goto dont_reorder;
719 720 721 722 723

	tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
724
		goto dont_reorder;
725 726 727 728 729 730 731 732 733 734 735 736 737 738

	/* new, potentially un-ordered, ampdu frame - process it */

	/* reset session timer */
	if (tid_agg_rx->timeout)
		mod_timer(&tid_agg_rx->session_timer,
			  TU_TO_EXP_TIME(tid_agg_rx->timeout));

	/* if this mpdu is fragmented - terminate rx aggregation session */
	sc = le16_to_cpu(hdr->seq_ctrl);
	if (sc & IEEE80211_SCTL_FRAG) {
		ieee80211_sta_stop_rx_ba_session(sta->sdata, sta->sta.addr,
			tid, 0, WLAN_REASON_QSTA_REQUIRE_SETUP);
		dev_kfree_skb(skb);
739
		return;
740 741
	}

742 743 744 745 746
	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, frames))
		return;

 dont_reorder:
	__skb_queue_tail(frames, skb);
747
}
748

749
static ieee80211_rx_result debug_noinline
750
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
751
{
752
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
753 754 755

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
756
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
757
			     rx->sta->last_seq_ctrl[rx->queue] ==
758
			     hdr->seq_ctrl)) {
759
			if (rx->flags & IEEE80211_RX_RA_MATCH) {
760 761 762
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
Johannes Berg's avatar
Johannes Berg committed
763
			return RX_DROP_MONITOR;
764
		} else
765
			rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
766 767 768 769
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
770
		return RX_DROP_MONITOR;
771 772 773 774 775
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
776 777
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
778 779 780
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
781

Johannes Berg's avatar
Johannes Berg committed
782
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
783 784
		return ieee80211_rx_mesh_check(rx);

785 786
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
787
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
788
		     (!rx->sta || !test_sta_flags(rx->sta, WLAN_STA_ASSOC)))) {
789 790 791 792
		if ((!ieee80211_has_fromds(hdr->frame_control) &&
		     !ieee80211_has_tods(hdr->frame_control) &&
		     ieee80211_is_data(hdr->frame_control)) ||
		    !(rx->flags & IEEE80211_RX_RA_MATCH)) {
793 794
			/* Drop IBSS frames and frames for other hosts
			 * silently. */
Johannes Berg's avatar
Johannes Berg committed
795
			return RX_DROP_MONITOR;
796 797
		}

Johannes Berg's avatar
Johannes Berg committed
798
		return RX_DROP_MONITOR;
799 800
	}

801
	return RX_CONTINUE;
802 803 804
}


805
static ieee80211_rx_result debug_noinline
806
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
807
{
Johannes Berg's avatar
Johannes Berg committed
808 809 810
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
811 812
	int keyidx;
	int hdrlen;
Johannes Berg's avatar
Johannes Berg committed
813
	ieee80211_rx_result result = RX_DROP_UNUSABLE;
814
	struct ieee80211_key *stakey = NULL;
815
	int mmie_keyidx = -1;
816

817 818 819
	/*
	 * Key selection 101
	 *
820
	 * There are four types of keys:
821
	 *  - GTK (group keys)
822
	 *  - IGTK (group keys for management frames)
823 824 825 826 827
	 *  - PTK (pairwise keys)
	 *  - STK (station-to-station pairwise keys)
	 *
	 * When selecting a key, we have to distinguish between multicast
	 * (including broadcast) and unicast frames, the latter can only
828 829 830 831
	 * use PTKs and STKs while the former always use GTKs and IGTKs.
	 * Unless, of course, actual WEP keys ("pre-RSNA") are used, then
	 * unicast frames can also use key indices like GTKs. Hence, if we
	 * don't have a PTK/STK we check the key index for a WEP key.
832
	 *
833 834 835 836
	 * Note that in a regular BSS, multicast frames are sent by the
	 * AP only, associated stations unicast the frame to the AP first
	 * which then multicasts it on their behalf.
	 *
837 838
	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
839 840 841
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
842 843 844
	 */

	/*
845
	 * No point in finding a key and decrypting if the frame is neither
846 847
	 * addressed to us nor a multicast frame.
	 */
848
	if (!(rx->flags & IEEE80211_RX_RA_MATCH))
849
		return RX_CONTINUE;
850

851 852 853
	/* start without a key */
	rx->key = NULL;

854 855 856
	if (rx->sta)
		stakey = rcu_dereference(rx->sta->key);

857 858 859
	if (!ieee80211_has_protected(hdr->frame_control))
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

860 861
	if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
		rx->key = stakey;
862 863 864
		/* Skip decryption if the frame is not protected. */
		if (!ieee80211_has_protected(hdr->frame_control))
			return RX_CONTINUE;
865 866
	} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
Johannes Berg's avatar
Johannes Berg committed
867 868
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
869 870 871 872 873 874
			return RX_CONTINUE;

		if (mmie_keyidx < NUM_DEFAULT_KEYS ||
		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
		rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
875 876 877 878 879 880 881 882 883 884 885 886 887 888 889
	} else if (!ieee80211_has_protected(hdr->frame_control)) {
		/*
		 * The frame was not protected, so skip decryption. However, we
		 * need to set rx->key if there is a key that could have been
		 * used so that the frame may be dropped if encryption would
		 * have been expected.
		 */
		struct ieee80211_key *key = NULL;
		if (ieee80211_is_mgmt(hdr->frame_control) &&
		    is_multicast_ether_addr(hdr->addr1) &&
		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
			rx->key = key;
		else if ((key = rcu_dereference(rx->sdata->default_key)))
			rx->key = key;
		return RX_CONTINUE;
890
	} else {
891 892 893 894 895 896 897 898 899
		/*
		 * The device doesn't give us the IV so we won't be
		 * able to look up the key. That's ok though, we
		 * don't need to decrypt the frame, we just won't
		 * be able to keep statistics accurate.
		 * Except for key threshold notifications, should
		 * we somehow allow the driver to tell us which key
		 * the hardware used if this flag is set?
		 */
Johannes Berg's avatar
Johannes Berg committed
900 901
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
902
			return RX_CONTINUE;
903

904
		hdrlen = ieee80211_hdrlen(hdr->frame_control);
905 906

		if (rx->skb->len < 8 + hdrlen)
Johannes Berg's avatar
Johannes Berg committed
907
			return RX_DROP_UNUSABLE; /* TODO: count this? */
908 909 910 911 912 913 914

		/*
		 * no need to call ieee80211_wep_get_keyidx,
		 * it verifies a bunch of things we've done already
		 */
		keyidx = rx->skb->data[hdrlen + 3] >> 6;

915
		rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
916 917 918 919 920 921

		/*
		 * RSNA-protected unicast frames should always be sent with
		 * pairwise or station-to-station keys, but for WEP we allow
		 * using a key index as well.
		 */
922
		if (rx->key && rx->key->conf.alg != ALG_WEP &&
923 924
		    !is_multicast_ether_addr(hdr->addr1))
			rx->key = NULL;
925 926
	}

927
	if (rx->key) {
928
		rx->key->tx_rx_count++;
929
		/* TODO: add threshold stuff again */
930
	} else {
Johannes Berg's avatar
Johannes Berg committed
931
		return RX_DROP_MONITOR;
932 933
	}

934 935
	/* Check for weak IVs if possible */
	if (rx->sta && rx->key->conf.alg == ALG_WEP &&
936
	    ieee80211_is_data(hdr->frame_control) &&
Johannes Berg's avatar
Johannes Berg committed
937 938
	    (!(status->flag & RX_FLAG_IV_STRIPPED) ||
	     !(status->flag & RX_FLAG_DECRYPTED)) &&
939 940 941
	    ieee80211_wep_is_weak_iv(rx->skb, rx->key))
		rx->sta->wep_weak_iv_count++;

942 943
	switch (rx->key->conf.alg) {
	case ALG_WEP:
944 945
		result = ieee80211_crypto_wep_decrypt(rx);
		break;
946
	case ALG_TKIP:
947 948
		result = ieee80211_crypto_tkip_decrypt(rx);
		break;
949
	case ALG_CCMP:
950 951
		result = ieee80211_crypto_ccmp_decrypt(rx);
		break;
952 953 954
	case ALG_AES_CMAC:
		result = ieee80211_crypto_aes_cmac_decrypt(rx);
		break;
955 956
	}

957
	/* either the frame has been decrypted or will be dropped */
Johannes Berg's avatar
Johannes Berg committed
958
	status->flag |= RX_FLAG_DECRYPTED;
959 960

	return result;
961 962
}

963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
{
	struct ieee80211_local *local;
	struct ieee80211_hdr *hdr;
	struct sk_buff *skb;

	local = rx->local;
	skb = rx->skb;
	hdr = (struct ieee80211_hdr *) skb->data;

	if (!local->pspolling)
		return RX_CONTINUE;

	if (!ieee80211_has_fromds(hdr->frame_control))
		/* this is not from AP */
		return RX_CONTINUE;

	if (!ieee80211_is_data(hdr->frame_control))
		return RX_CONTINUE;

	if (!ieee80211_has_moredata(hdr->frame_control)) {
		/* AP has no more frames buffered for us */
		local->pspolling = false;
		return RX_CONTINUE;
	}

	/* more data bit is set, let's request a new frame from the AP */
	ieee80211_send_pspoll(local, rx->sdata);

	return RX_CONTINUE;
}

996
static void ap_sta_ps_start(struct sta_info *sta)
997
{
998
	struct ieee80211_sub_if_data *sdata = sta->sdata;
999
	struct ieee80211_local *local = sdata->local;
1000

1001
	atomic_inc(&sdata->bss->num_sta_ps);
1002
	set_sta_flags(sta, WLAN_STA_PS_STA);
Johannes Berg's avatar
Johannes Berg committed
1003
	drv_sta_notify(local, sdata, STA_NOTIFY_SLEEP, &sta->sta);
1004
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1005
	printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
1006
	       sdata->name, sta->sta.addr, sta->sta.aid);
1007 1008 1009
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
}

1010
static void ap_sta_ps_end(struct sta_info *sta)
1011
{
1012
	struct ieee80211_sub_if_data *sdata = sta->sdata;
1013

1014
	atomic_dec(&sdata->bss->num_sta_ps);
1015

1016
	clear_sta_flags(sta, WLAN_STA_PS_STA);
1017

1018
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1019
	printk(KERN_DEBUG "%s: STA %pM aid %d exits power save mode\n",
1020
	       sdata->name, sta->sta.addr, sta->sta.aid);
1021
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1022

1023
	if (test_sta_flags(sta, WLAN_STA_PS_DRIVER)) {
1024
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1025
		printk(KERN_DEBUG "%s: STA %pM aid %d driver-ps-blocked\n",
1026
		       sdata->name, sta->sta.addr, sta->sta.aid);
1027
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
1028 1029 1030 1031
		return;
	}

	ieee80211_sta_ps_deliver_wakeup(sta);
1032 1033
}

1034
static ieee80211_rx_result debug_noinline
1035
ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
1036 1037
{
	struct sta_info *sta = rx->sta;
Johannes Berg's avatar
Johannes Berg committed
1038 1039 1040
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1041 1042

	if (!sta)
1043
		return RX_CONTINUE;
1044

1045 1046 1047 1048 1049
	/*
	 * Update last_rx only for IBSS packets which are for the current
	 * BSSID to avoid keeping the current IBSS network alive in cases
	 * where other STAs start using different BSSID.
	 */
1050
	if (rx->sdata->vif.type == NL80211_IFTYPE_ADHOC) {
1051
		u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
1052
						NL80211_IFTYPE_ADHOC);
1053
		if (compare_ether_addr(bssid, rx->sdata->u.ibss.bssid) == 0)
1054
			sta->last_rx = jiffies;
1055 1056
	} else if (!is_multicast_ether_addr(hdr->addr1)) {
		/*
1057 1058
		 * Mesh beacons will update last_rx when if they are found to
		 * match the current local configuration when processed.
1059
		 */
1060
		sta->last_rx = jiffies;
1061 1062
	}

1063
	if (!(rx->flags & IEEE80211_RX_RA_MATCH))
1064
		return RX_CONTINUE;
1065

1066 1067 1068
	if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)
		ieee80211_sta_rx_notify(rx->sdata, hdr);

1069 1070
	sta->rx_fragments++;
	sta->rx_bytes += rx->skb->len;
Johannes Berg's avatar
Johannes Berg committed
1071
	sta->last_signal = status->signal;
1072

1073 1074 1075 1076
	/*
	 * Change STA power saving mode only at the end of a frame
	 * exchange sequence.
	 */
1077
	if (!ieee80211_has_morefrags(hdr->frame_control) &&
1078 1079
	    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
	     rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)) {
1080
		if (test_sta_flags(sta, WLAN_STA_PS_STA)) {
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
			/*
			 * Ignore doze->wake transitions that are
			 * indicated by non-data frames, the standard
			 * is unclear here, but for example going to
			 * PS mode and then scanning would cause a
			 * doze->wake transition for the probe request,
			 * and that is clearly undesirable.
			 */
			if (ieee80211_is_data(hdr->frame_control) &&
			    !ieee80211_has_pm(hdr->frame_control))
1091
				ap_sta_ps_end(sta);
1092 1093 1094 1095
		} else {
			if (ieee80211_has_pm(hdr->frame_control))
				ap_sta_ps_start(sta);
		}
1096 1097
	}

1098 1099 1100 1101 1102 1103
	/*
	 * Drop (qos-)data::nullfunc frames silently, since they
	 * are used only to control station power saving mode.
	 */
	if (ieee80211_is_nullfunc(hdr->frame_control) ||
	    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
1104
		I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116

		/*
		 * If we receive a 4-addr nullfunc frame from a STA
		 * that was not moved to a 4-addr STA vlan yet, drop
		 * the frame to the monitor interface, to make sure
		 * that hostapd sees it
		 */
		if (ieee80211_has_a4(hdr->frame_control) &&
		    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
		     (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
		      !rx->sdata->u.vlan.sta)))
			return RX_DROP_MONITOR;
1117 1118 1119 1120
		/*
		 * Update counter and free packet here to avoid
		 * counting this as a dropped packed.
		 */
1121 1122
		sta->rx_packets++;
		dev_kfree_skb(rx->skb);
1123
		return RX_QUEUED;
1124 1125
	}

1126
	return RX_CONTINUE;
1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142
} /* ieee80211_rx_h_sta_process */

static inline struct ieee80211_fragment_entry *
ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata,
			 unsigned int frag, unsigned int seq, int rx_queue,
			 struct sk_buff **skb)
{
	struct ieee80211_fragment_entry *entry;
	int idx;

	idx = sdata->fragment_next;
	entry = &sdata->fragments[sdata->fragment_next++];
	if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX)
		sdata->fragment_next = 0;

	if (!skb_queue_empty(&entry->skb_list)) {