rx.c 85.9 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
#include <linux/slab.h>
14 15 16 17
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
18
#include <linux/rcupdate.h>
19
#include <linux/export.h>
20 21
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
22
#include <asm/unaligned.h>
23 24

#include "ieee80211_i.h"
25
#include "driver-ops.h"
Johannes Berg's avatar
Johannes Berg committed
26
#include "led.h"
27
#include "mesh.h"
28 29 30 31
#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"
32
#include "rate.h"
33

34 35 36 37 38 39 40
/*
 * 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,
41
					   struct sk_buff *skb)
42 43 44
{
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
Zhu Yi's avatar
Zhu Yi committed
45
			__pskb_trim(skb, skb->len - FCS_LEN);
46 47 48 49 50 51 52 53 54 55 56
		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
			skb = NULL;
		}
	}

	return skb;
}

57
static inline int should_drop_frame(struct sk_buff *skb,
58
				    int present_fcs_len)
59
{
60
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
61
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
62 63 64

	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		return 1;
65
	if (unlikely(skb->len < 16 + present_fcs_len))
66
		return 1;
67 68 69
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
70 71 72 73
		return 1;
	return 0;
}

74 75 76 77 78 79 80 81 82
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;

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

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

91 92 93
	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

94 95 96
	return len;
}

97
/*
98 99 100 101 102 103 104 105
 * 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,
106
				 int rtap_len, bool has_fcs)
107
{
108
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
109 110
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
111
	u16 rx_flags = 0;
112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128

	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 */
Johannes Berg's avatar
Johannes Berg committed
129
	if (status->flag & RX_FLAG_MACTIME_MPDU) {
130
		put_unaligned_le64(status->mactime, pos);
131 132 133 134 135 136
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
		pos += 8;
	}

	/* IEEE80211_RADIOTAP_FLAGS */
137
	if (has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS))
138
		*pos |= IEEE80211_RADIOTAP_F_FCS;
Johannes Berg's avatar
Johannes Berg committed
139 140
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
141 142
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
143 144 145
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
146
	if (!rate || status->flag & RX_FLAG_HT) {
147
		/*
148
		 * Without rate information don't add it. If we have,
149
		 * MCS information is a separate field in radiotap,
150 151
		 * added below. The byte here is needed as padding
		 * for the channel though, so initialise it to 0.
152 153
		 */
		*pos = 0;
154
	} else {
155
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
156
		*pos = rate->bitrate / 5;
157
	}
158 159 160
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
161
	put_unaligned_le16(status->freq, pos);
162 163
	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
164 165
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
166 167 168
	else if (status->flag & RX_FLAG_HT)
		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
169
	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
170 171
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
172
	else if (rate)
173 174
		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
175 176
	else
		put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
177 178 179
	pos += 2;

	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
180 181
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
	    !(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197
		*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 */
198
	if ((pos - (u8 *)rthdr) & 1)
199
		pos++;
Johannes Berg's avatar
Johannes Berg committed
200
	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
201 202
		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
203
	pos += 2;
204 205 206 207 208 209 210 211 212 213 214 215 216 217

	if (status->flag & RX_FLAG_HT) {
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
		*pos++ = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
		*pos = 0;
		if (status->flag & RX_FLAG_SHORT_GI)
			*pos |= IEEE80211_RADIOTAP_MCS_SGI;
		if (status->flag & RX_FLAG_40MHZ)
			*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
		pos++;
		*pos++ = status->rate_idx;
	}
218 219
}

220 221 222 223 224 225 226
/*
 * 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,
227
		     struct ieee80211_rate *rate)
228
{
229
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
230
	struct ieee80211_sub_if_data *sdata;
231
	int needed_headroom;
232 233 234 235 236 237 238 239 240 241 242 243
	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.
	 */
244 245 246

	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_len(local, status);
247 248 249 250

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

Zhu Yi's avatar
Zhu Yi committed
251 252 253 254 255 256
	/* make sure hdr->frame_control is on the linear part */
	if (!pskb_may_pull(origskb, 2)) {
		dev_kfree_skb(origskb);
		return NULL;
	}

257
	if (!local->monitors) {
258
		if (should_drop_frame(origskb, present_fcs_len)) {
259 260 261 262
			dev_kfree_skb(origskb);
			return NULL;
		}

263
		return remove_monitor_info(local, origskb);
264 265
	}

266
	if (should_drop_frame(origskb, present_fcs_len)) {
267 268 269 270 271 272 273 274 275 276 277 278
		/* 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 &&
279
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
280 281 282 283 284 285 286 287 288 289
			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);

290
		origskb = remove_monitor_info(local, origskb);
291 292 293 294 295

		if (!skb)
			return origskb;
	}

296
	/* prepend radiotap information */
297 298
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
					 true);
299

300
	skb_reset_mac_header(skb);
301 302 303 304 305
	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) {
306
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
307 308
			continue;

309 310 311
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

312
		if (!ieee80211_sdata_running(sdata))
313 314
			continue;

315 316 317 318
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
319
				netif_receive_skb(skb2);
320 321 322 323 324 325 326 327 328 329
			}
		}

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

	if (prev_dev) {
		skb->dev = prev_dev;
330
		netif_receive_skb(skb);
331 332 333 334 335 336 337
	} else
		dev_kfree_skb(skb);

	return origskb;
}


338
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
339
{
340
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
341
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
342
	int tid, seqno_idx, security_idx;
343 344

	/* does the frame have a qos control field? */
345 346
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
347
		/* frame has qos control */
348
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
349
		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
350
			status->rx_flags |= IEEE80211_RX_AMSDU;
351 352 353

		seqno_idx = tid;
		security_idx = tid;
354
	} else {
355 356 357 358 359 360 361 362 363 364 365
		/*
		 * 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.
		 */
366 367 368 369 370
		seqno_idx = NUM_RX_DATA_QUEUES;
		security_idx = 0;
		if (ieee80211_is_mgmt(hdr->frame_control))
			security_idx = NUM_RX_DATA_QUEUES;
		tid = 0;
371
	}
372

373 374
	rx->seqno_idx = seqno_idx;
	rx->security_idx = security_idx;
375 376 377
	/* 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;
378
}
379

380 381 382 383 384 385 386 387 388 389 390
/**
 * 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
391 392 393
 * 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.
394 395 396 397 398 399 400
 *
 * 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.
 *
Lucas De Marchi's avatar
Lucas De Marchi committed
401
 * Padding like Atheros hardware adds which is between the 802.11 header and
402 403 404 405
 * 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)
406
{
407 408 409
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
410
#endif
411 412
}

413

414 415
/* rx handlers */

416
static ieee80211_rx_result debug_noinline
417
ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
418 419
{
	struct ieee80211_local *local = rx->local;
420
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
421 422
	struct sk_buff *skb = rx->skb;

423 424
	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
		   !local->sched_scanning))
425 426
		return RX_CONTINUE;

427
	if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
428
	    test_bit(SCAN_SW_SCANNING, &local->scanning) ||
429
	    test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning) ||
430
	    local->sched_scanning)
431
		return ieee80211_scan_rx(rx->sdata, skb);
Zhu Yi's avatar
Zhu Yi committed
432

433 434 435
	/* scanning finished during invoking of handlers */
	I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
	return RX_DROP_UNUSABLE;
436 437
}

438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483

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);
}


484
static ieee80211_rx_result
485
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
486
{
487
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
488
	char *dev_addr = rx->sdata->vif.addr;
489

490
	if (ieee80211_is_data(hdr->frame_control)) {
491 492 493 494
		if (is_multicast_ether_addr(hdr->addr1)) {
			if (ieee80211_has_tods(hdr->frame_control) ||
				!ieee80211_has_fromds(hdr->frame_control))
				return RX_DROP_MONITOR;
495
			if (compare_ether_addr(hdr->addr3, dev_addr) == 0)
496 497 498 499
				return RX_DROP_MONITOR;
		} else {
			if (!ieee80211_has_a4(hdr->frame_control))
				return RX_DROP_MONITOR;
500
			if (compare_ether_addr(hdr->addr4, dev_addr) == 0)
501 502
				return RX_DROP_MONITOR;
		}
503 504 505 506 507 508
	}

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

509
	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
510
		struct ieee80211_mgmt *mgmt;
511

512
		if (!ieee80211_is_mgmt(hdr->frame_control))
513 514
			return RX_DROP_MONITOR;

515
		if (ieee80211_is_action(hdr->frame_control)) {
516
			u8 category;
517
			mgmt = (struct ieee80211_mgmt *)hdr;
518 519 520
			category = mgmt->u.action.category;
			if (category != WLAN_CATEGORY_MESH_ACTION &&
				category != WLAN_CATEGORY_SELF_PROTECTED)
521 522 523 524
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

525 526
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
527 528
		    ieee80211_is_beacon(hdr->frame_control) ||
		    ieee80211_is_auth(hdr->frame_control))
529 530 531 532 533 534
			return RX_CONTINUE;

		return RX_DROP_MONITOR;

	}

Johannes Berg's avatar
Johannes Berg committed
535 536
	return RX_CONTINUE;
}
537

538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558
#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,
559
					    int index)
560
{
561
	struct ieee80211_local *local = hw_to_local(hw);
562
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
563
	struct ieee80211_rx_status *status;
564

565 566
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

567 568 569
	if (!skb)
		goto no_frame;

570
	/* release the frame from the reorder ring buffer */
571 572
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
573 574
	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
575
	skb_queue_tail(&local->rx_skb_queue, skb);
576 577 578 579 580 581 582

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,
583
					     u16 head_seq_num)
584 585 586
{
	int index;

587 588
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

589 590 591
	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;
592
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
593 594 595 596 597 598 599 600 601
	}
}

/*
 * 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.
602 603
 *
 * Callers must hold tid_agg_rx->reorder_lock.
604 605 606
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

607
static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
608
					  struct tid_ampdu_rx *tid_agg_rx)
609
{
610
	int index, j;
611

612 613
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

614 615 616 617
	/* 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] &&
618
	    tid_agg_rx->stored_mpdu_num) {
619 620 621 622 623 624 625 626 627 628 629
		/*
		 * No buffers ready to be released, but check whether any
		 * frames in the reorder buffer have timed out.
		 */
		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;
			}
630 631
			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
632
					HT_RX_REORDER_BUF_TIMEOUT))
633
				goto set_release_timer;
634 635 636

#ifdef CONFIG_MAC80211_HT_DEBUG
			if (net_ratelimit())
Joe Perches's avatar
Joe Perches committed
637 638
				wiphy_debug(hw->wiphy,
					    "release an RX reorder frame due to timeout on earlier frames\n");
639
#endif
640
			ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
641 642 643 644 645 646 647 648 649

			/*
			 * 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]) {
650
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
651 652 653
		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}
654 655 656 657 658 659 660 661 662 663 664 665 666 667

	if (tid_agg_rx->stored_mpdu_num) {
		j = index = seq_sub(tid_agg_rx->head_seq_num,
				    tid_agg_rx->ssn) % tid_agg_rx->buf_size;

		for (; j != (index - 1) % tid_agg_rx->buf_size;
		     j = (j + 1) % tid_agg_rx->buf_size) {
			if (tid_agg_rx->reorder_buf[j])
				break;
		}

 set_release_timer:

		mod_timer(&tid_agg_rx->reorder_timer,
668
			  tid_agg_rx->reorder_time[j] + 1 +
669 670 671 672
			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
673 674
}

675 676 677 678 679 680 681
/*
 * 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,
682
					     struct sk_buff *skb)
683 684 685 686 687 688
{
	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;
689
	bool ret = true;
690

691 692
	spin_lock(&tid_agg_rx->reorder_lock);

693 694 695 696 697 698
	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);
699
		goto out;
700 701 702 703 704 705 706 707 708
	}

	/*
	 * 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 */
709
		ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num);
710 711 712 713 714 715 716 717 718
	}

	/* 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);
719
		goto out;
720 721 722 723 724
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
725 726
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
727 728 729 730
	 */
	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);
731 732
		ret = false;
		goto out;
733 734 735 736 737 738
	}

	/* 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++;
739
	ieee80211_sta_reorder_release(hw, tid_agg_rx);
740

741 742 743
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
744 745 746 747 748 749
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
750
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
751
{
752 753
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
754 755
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
756
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
757
	struct sta_info *sta = rx->sta;
758 759
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
760
	u8 tid, ack_policy;
761 762

	if (!ieee80211_is_data_qos(hdr->frame_control))
763
		goto dont_reorder;
764 765 766 767 768 769 770

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

	if (!sta)
771
		goto dont_reorder;
772

773 774
	ack_policy = *ieee80211_get_qos_ctl(hdr) &
		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
775 776
	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

777 778 779
	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
780 781 782

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
783
		goto dont_reorder;
784

785 786 787 788 789
	/* not part of a BA session */
	if (ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
	    ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
		goto dont_reorder;

790 791 792 793
	/* not actually part of this BA session */
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
		goto dont_reorder;

794 795 796 797
	/* new, potentially un-ordered, ampdu frame - process it */

	/* reset session timer */
	if (tid_agg_rx->timeout)
798
		tid_agg_rx->last_rx = jiffies;
799 800 801 802

	/* if this mpdu is fragmented - terminate rx aggregation session */
	sc = le16_to_cpu(hdr->seq_ctrl);
	if (sc & IEEE80211_SCTL_FRAG) {
803
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
804 805
		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
806
		return;
807 808
	}

809 810 811 812 813 814 815
	/*
	 * No locking needed -- we will only ever process one
	 * RX packet at a time, and thus own tid_agg_rx. All
	 * other code manipulating it needs to (and does) make
	 * sure that we cannot get to it any more before doing
	 * anything with it.
	 */
816
	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb))
817 818 819
		return;

 dont_reorder:
820
	skb_queue_tail(&local->rx_skb_queue, skb);
821
}
822

823
static ieee80211_rx_result debug_noinline
824
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
825
{
826
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
827
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
828 829 830

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
831
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
832
			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
833
			     hdr->seq_ctrl)) {
834
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
835 836 837
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
838
			return RX_DROP_UNUSABLE;
839
		} else
840
			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
841 842 843 844
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
845
		return RX_DROP_MONITOR;
846 847 848 849 850
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
851 852
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
853 854 855
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
856

Johannes Berg's avatar
Johannes Berg committed
857
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
858 859
		return ieee80211_rx_mesh_check(rx);

860 861
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
862
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
Bill Jordan's avatar
Bill Jordan committed
863
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
864
		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
865 866 867 868 869 870
		/*
		 * accept port control frames from the AP even when it's not
		 * yet marked ASSOC to prevent a race where we don't set the
		 * assoc bit quickly enough before it sends the first frame
		 */
		if (rx->sta && rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
871 872 873 874 875 876 877 878 879 880 881
		    ieee80211_is_data_present(hdr->frame_control)) {
			u16 ethertype;
			u8 *payload;

			payload = rx->skb->data +
				ieee80211_hdrlen(hdr->frame_control);
			ethertype = (payload[6] << 8) | payload[7];
			if (cpu_to_be16(ethertype) ==
			    rx->sdata->control_port_protocol)
				return RX_CONTINUE;
		}
882 883 884 885 886 887 888

		if (rx->sdata->vif.type == NL80211_IFTYPE_AP &&
		    cfg80211_rx_spurious_frame(rx->sdata->dev,
					       hdr->addr2,
					       GFP_ATOMIC))
			return RX_DROP_UNUSABLE;

Johannes Berg's avatar
Johannes Berg committed
889
		return RX_DROP_MONITOR;
890
	}
891

892
	return RX_CONTINUE;
893 894 895
}


896
static ieee80211_rx_result debug_noinline
897
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
898
{
Johannes Berg's avatar
Johannes Berg committed
899 900 901
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
902 903
	int keyidx;
	int hdrlen;
Johannes Berg's avatar
Johannes Berg committed
904
	ieee80211_rx_result result = RX_DROP_UNUSABLE;
905
	struct ieee80211_key *sta_ptk = NULL;
906
	int mmie_keyidx = -1;
907
	__le16 fc;
908

909 910 911
	/*
	 * Key selection 101
	 *
912
	 * There are four types of keys:
913
	 *  - GTK (group keys)
914
	 *  - IGTK (group keys for management frames)
915 916 917 918 919
	 *  - 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
920 921 922 923
	 * 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.
924
	 *
925 926 927 928
	 * 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.
	 *
929 930
	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
931 932 933
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
934 935 936
	 */

	/*
937
	 * No point in finding a key and decrypting if the frame is neither
938 939
	 * addressed to us nor a multicast frame.
	 */
940
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
941
		return RX_CONTINUE;
942

943 944 945
	/* start without a key */
	rx->key = NULL;

946
	if (rx->sta)
947
		sta_ptk = rcu_dereference(rx->sta->ptk);
948

949 950 951
	fc = hdr->frame_control;

	if (!ieee80211_has_protected(fc))
952 953
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

954 955
	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
		rx->key = sta_ptk;
956 957 958
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
			return RX_CONTINUE;
959
		/* Skip decryption if the frame is not protected. */
960
		if (!ieee80211_has_protected(fc))
961
			return RX_CONTINUE;
962 963
	} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
Johannes Berg's avatar
Johannes Berg committed
964 965
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
966 967 968 969 970
			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 */
971 972 973 974
		if (rx->sta)
			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
		if (!rx->key)
			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
975
	} else if (!ieee80211_has_protected(fc)) {
976 977 978 979 980 981 982
		/*
		 * 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;
983 984 985
		struct ieee80211_sub_if_data *sdata = rx->sdata;
		int i;

986
		if (ieee80211_is_mgmt(fc) &&
987 988 989
		    is_multicast_ether_addr(hdr->addr1) &&
		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
			rx->key = key;
990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
		else {
			if (rx->sta) {
				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
					key = rcu_dereference(rx->sta->gtk[i]);
					if (key)
						break;
				}
			}
			if (!key) {
				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
					key = rcu_dereference(sdata->keys[i]);
					if (key)
						break;
				}
			}
			if (key)
				rx->key = key;
		}
1008
		return RX_CONTINUE;
1009
	} else {
1010
		u8 keyid;
1011 1012 1013 1014 1015 1016 1017 1018 1019
		/*
		 * 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
1020 1021
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
1022
			return RX_CONTINUE;
1023

1024
		hdrlen = ieee80211_hdrlen(fc);
1025 1026

		if (rx->skb->len < 8 + hdrlen)
Johannes Berg's avatar
Johannes Berg committed
1027
			return RX_DROP_UNUSABLE; /* TODO: count this? */
1028 1029 1030 1031 1032

		/*
		 * no need to call ieee80211_wep_get_keyidx,
		 * it verifies a bunch of things we've done already
		 */
1033 1034
		skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
		keyidx = keyid >> 6;
1035

1036 1037 1038
		/* check per-station GTK first, if multicast packet */
		if (is_multicast_ether_addr(hdr->addr1) && rx->sta)
			rx->key = rcu_dereference(rx->sta->gtk[keyidx]);
1039

1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
		/* if not found, try default key */
		if (!rx->key) {
			rx->key = rcu_dereference(rx->sdata->keys[keyidx]);

			/*
			 * 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.
			 */
			if (rx->key &&
			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP40 &&
			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP104 &&
			    !is_multicast_ether_addr(hdr->addr1))
				rx->key = NULL;
		}