rx.c 86.3 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 22 23
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>

#include "ieee80211_i.h"
24
#include "driver-ops.h"
Johannes Berg's avatar
Johannes Berg committed
25
#include "led.h"
26
#include "mesh.h"
27 28 29 30
#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"
31
#include "rate.h"
32

33 34 35 36 37 38 39
/*
 * 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,
40
					   struct sk_buff *skb)
41 42 43
{
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
Zhu Yi's avatar
Zhu Yi committed
44
			__pskb_trim(skb, skb->len - FCS_LEN);
45 46 47 48 49 50 51 52 53 54 55
		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
			skb = NULL;
		}
	}

	return skb;
}

56
static inline int should_drop_frame(struct sk_buff *skb,
57
				    int present_fcs_len)
58
{
59
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
60
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
61 62 63

	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		return 1;
64
	if (unlikely(skb->len < 16 + present_fcs_len))
65
		return 1;
66 67 68
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
69 70 71 72
		return 1;
	return 0;
}

73 74 75 76 77 78 79 80 81
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
82
	if (status->flag & RX_FLAG_MACTIME_MPDU)
83
		len += 8;
Johannes Berg's avatar
Johannes Berg committed
84
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
85 86 87 88 89
		len += 1;

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

90 91 92
	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

93 94 95
	return len;
}

96
/*
97 98 99 100 101 102 103 104 105 106
 * 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)
{
107
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
108 109
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
110
	u16 rx_flags = 0;
111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127

	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
128
	if (status->flag & RX_FLAG_MACTIME_MPDU) {
129
		put_unaligned_le64(status->mactime, pos);
130 131 132 133 134 135 136 137
		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
138 139
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
140 141
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
142 143 144
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
145
	if (!rate || status->flag & RX_FLAG_HT) {
146
		/*
147
		 * Without rate information don't add it. If we have,
148
		 * MCS information is a separate field in radiotap,
149 150
		 * added below. The byte here is needed as padding
		 * for the channel though, so initialise it to 0.
151 152
		 */
		*pos = 0;
153
	} else {
154
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
155
		*pos = rate->bitrate / 5;
156
	}
157 158 159
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
160
	put_unaligned_le16(status->freq, pos);
161 162
	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
163 164
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
165 166 167
	else if (status->flag & RX_FLAG_HT)
		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
168
	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
169 170
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
171
	else if (rate)
172 173
		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
174 175
	else
		put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195
	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 */
196
	if ((pos - (u8 *)rthdr) & 1)
197
		pos++;
Johannes Berg's avatar
Johannes Berg committed
198
	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
199 200
		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
201
	pos += 2;
202 203 204 205 206 207 208 209 210 211 212 213 214 215

	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;
	}
216 217
}

218 219 220 221 222 223 224
/*
 * 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,
225
		     struct ieee80211_rate *rate)
226
{
227
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
228 229 230 231 232 233 234 235 236 237 238 239 240 241
	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.
	 */
242 243 244

	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_len(local, status);
245 246 247 248

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

Zhu Yi's avatar
Zhu Yi committed
249 250 251 252 253 254
	/* make sure hdr->frame_control is on the linear part */
	if (!pskb_may_pull(origskb, 2)) {
		dev_kfree_skb(origskb);
		return NULL;
	}

255
	if (!local->monitors) {
256
		if (should_drop_frame(origskb, present_fcs_len)) {
257 258 259 260
			dev_kfree_skb(origskb);
			return NULL;
		}

261
		return remove_monitor_info(local, origskb);
262 263
	}

264
	if (should_drop_frame(origskb, present_fcs_len)) {
265 266 267 268 269 270 271 272 273 274 275 276
		/* 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 &&
277
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
278 279 280 281 282 283 284 285 286 287
			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);

288
		origskb = remove_monitor_info(local, origskb);
289 290 291 292 293

		if (!skb)
			return origskb;
	}

294 295
	/* prepend radiotap information */
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
296

297
	skb_reset_mac_header(skb);
298 299 300 301 302
	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) {
303
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
304 305
			continue;

306 307 308
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

309
		if (!ieee80211_sdata_running(sdata))
310 311
			continue;

312 313 314 315
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
316
				netif_receive_skb(skb2);
317 318 319 320 321 322 323 324 325 326
			}
		}

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

	if (prev_dev) {
		skb->dev = prev_dev;
327
		netif_receive_skb(skb);
328 329 330 331 332 333 334
	} else
		dev_kfree_skb(skb);

	return origskb;
}


335
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
336
{
337
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
338
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
339
	int tid, seqno_idx, security_idx;
340 341

	/* does the frame have a qos control field? */
342 343
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
344
		/* frame has qos control */
345
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
346
		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
347
			status->rx_flags |= IEEE80211_RX_AMSDU;
348 349 350

		seqno_idx = tid;
		security_idx = tid;
351
	} else {
352 353 354 355 356 357 358 359 360 361 362
		/*
		 * 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.
		 */
363 364 365 366 367
		seqno_idx = NUM_RX_DATA_QUEUES;
		security_idx = 0;
		if (ieee80211_is_mgmt(hdr->frame_control))
			security_idx = NUM_RX_DATA_QUEUES;
		tid = 0;
368
	}
369

370 371
	rx->seqno_idx = seqno_idx;
	rx->security_idx = security_idx;
372 373 374
	/* 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;
375
}
376

377 378 379 380 381 382 383 384 385 386 387
/**
 * 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
388 389 390
 * 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.
391 392 393 394 395 396 397
 *
 * 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
398
 * Padding like Atheros hardware adds which is between the 802.11 header and
399 400 401 402
 * 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)
403
{
404 405 406
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
407
#endif
408 409
}

410

411 412
/* rx handlers */

413
static ieee80211_rx_result debug_noinline
414
ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
415 416
{
	struct ieee80211_local *local = rx->local;
417
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
418 419
	struct sk_buff *skb = rx->skb;

420 421
	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
		   !local->sched_scanning))
422 423
		return RX_CONTINUE;

424
	if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
425 426
	    test_bit(SCAN_SW_SCANNING, &local->scanning) ||
	    local->sched_scanning)
427
		return ieee80211_scan_rx(rx->sdata, skb);
Zhu Yi's avatar
Zhu Yi committed
428

429 430 431
	/* scanning finished during invoking of handlers */
	I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
	return RX_DROP_UNUSABLE;
432 433
}

434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479

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);
}


480
static ieee80211_rx_result
481
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
482
{
483
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
484
	char *dev_addr = rx->sdata->vif.addr;
485

486
	if (ieee80211_is_data(hdr->frame_control)) {
487 488 489 490 491 492 493 494 495 496 497 498
		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;
		}
499 500 501 502 503 504
	}

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

505
	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
506
		struct ieee80211_mgmt *mgmt;
507

508
		if (!ieee80211_is_mgmt(hdr->frame_control))
509 510
			return RX_DROP_MONITOR;

511
		if (ieee80211_is_action(hdr->frame_control)) {
512
			u8 category;
513
			mgmt = (struct ieee80211_mgmt *)hdr;
514 515 516
			category = mgmt->u.action.category;
			if (category != WLAN_CATEGORY_MESH_ACTION &&
				category != WLAN_CATEGORY_SELF_PROTECTED)
517 518 519 520
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

521 522
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
523 524
		    ieee80211_is_beacon(hdr->frame_control) ||
		    ieee80211_is_auth(hdr->frame_control))
525 526 527 528 529 530
			return RX_CONTINUE;

		return RX_DROP_MONITOR;

	}

Johannes Berg's avatar
Johannes Berg committed
531 532
	return RX_CONTINUE;
}
533

534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554
#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,
555
					    int index)
556
{
557
	struct ieee80211_local *local = hw_to_local(hw);
558
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
559
	struct ieee80211_rx_status *status;
560

561 562
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

563 564 565
	if (!skb)
		goto no_frame;

566
	/* release the frame from the reorder ring buffer */
567 568
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
569 570
	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
571
	skb_queue_tail(&local->rx_skb_queue, skb);
572 573 574 575 576 577 578

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,
579
					     u16 head_seq_num)
580 581 582
{
	int index;

583 584
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

585 586 587
	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;
588
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
589 590 591 592 593 594 595 596 597
	}
}

/*
 * 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.
598 599
 *
 * Callers must hold tid_agg_rx->reorder_lock.
600 601 602
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

603
static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
604
					  struct tid_ampdu_rx *tid_agg_rx)
605
{
606
	int index, j;
607

608 609
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

610 611 612 613
	/* 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] &&
614
	    tid_agg_rx->stored_mpdu_num) {
615 616 617 618 619 620 621 622 623 624 625
		/*
		 * 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;
			}
626 627
			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
628
					HT_RX_REORDER_BUF_TIMEOUT))
629
				goto set_release_timer;
630 631 632

#ifdef CONFIG_MAC80211_HT_DEBUG
			if (net_ratelimit())
Joe Perches's avatar
Joe Perches committed
633 634
				wiphy_debug(hw->wiphy,
					    "release an RX reorder frame due to timeout on earlier frames\n");
635
#endif
636
			ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
637 638 639 640 641 642 643 644 645

			/*
			 * 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]) {
646
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
647 648 649
		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}
650 651 652 653 654 655 656 657 658 659 660 661 662 663

	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,
664
			  tid_agg_rx->reorder_time[j] + 1 +
665 666 667 668
			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
669 670
}

671 672 673 674 675 676 677
/*
 * 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,
678
					     struct sk_buff *skb)
679 680 681 682 683 684
{
	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;
685
	bool ret = true;
686

687 688
	spin_lock(&tid_agg_rx->reorder_lock);

689 690 691 692 693 694
	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);
695
		goto out;
696 697 698 699 700 701 702 703 704
	}

	/*
	 * 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 */
705
		ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num);
706 707 708 709 710 711 712 713 714
	}

	/* 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);
715
		goto out;
716 717 718 719 720
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
721 722
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
723 724 725 726
	 */
	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);
727 728
		ret = false;
		goto out;
729 730 731 732 733 734
	}

	/* 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++;
735
	ieee80211_sta_reorder_release(hw, tid_agg_rx);
736

737 738 739
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
740 741 742 743 744 745
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
746
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
747
{
748 749
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
750 751
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
752
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
753
	struct sta_info *sta = rx->sta;
754 755
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
756
	u8 tid, ack_policy;
757 758

	if (!ieee80211_is_data_qos(hdr->frame_control))
759
		goto dont_reorder;
760 761 762 763 764 765 766

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

	if (!sta)
767
		goto dont_reorder;
768

769 770
	ack_policy = *ieee80211_get_qos_ctl(hdr) &
		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
771 772
	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

773 774 775
	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
776 777 778

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
779
		goto dont_reorder;
780

781 782 783 784 785
	/* 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;

786 787 788 789
	/* not actually part of this BA session */
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
		goto dont_reorder;

790 791 792 793 794 795 796 797 798 799
	/* 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) {
800
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
801 802
		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
803
		return;
804 805
	}

806 807 808 809 810 811 812
	/*
	 * 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.
	 */
813
	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb))
814 815 816
		return;

 dont_reorder:
817
	skb_queue_tail(&local->rx_skb_queue, skb);
818
}
819

820
static ieee80211_rx_result debug_noinline
821
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
822
{
823
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
824
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
825 826 827

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
828
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
829
			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
830
			     hdr->seq_ctrl)) {
831
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
832 833 834
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
835
			return RX_DROP_UNUSABLE;
836
		} else
837
			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
838 839 840 841
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
842
		return RX_DROP_MONITOR;
843 844 845 846 847
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
848 849
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
850 851 852
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
853

Johannes Berg's avatar
Johannes Berg committed
854
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
855 856
		return ieee80211_rx_mesh_check(rx);

857 858
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
859
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
Bill Jordan's avatar
Bill Jordan committed
860
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
861
		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
862 863 864 865 866 867
		/*
		 * 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 &&
868 869 870 871 872 873 874 875 876 877 878
		    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;
		}
879 880 881 882 883 884 885

		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
886
		return RX_DROP_MONITOR;
887
	}
888

889
	return RX_CONTINUE;
890 891 892
}


893
static ieee80211_rx_result debug_noinline
894
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
895
{
Johannes Berg's avatar
Johannes Berg committed
896 897 898
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
899 900
	int keyidx;
	int hdrlen;
Johannes Berg's avatar
Johannes Berg committed
901
	ieee80211_rx_result result = RX_DROP_UNUSABLE;
902
	struct ieee80211_key *sta_ptk = NULL;
903
	int mmie_keyidx = -1;
904
	__le16 fc;
905

906 907 908
	/*
	 * Key selection 101
	 *
909
	 * There are four types of keys:
910
	 *  - GTK (group keys)
911
	 *  - IGTK (group keys for management frames)
912 913 914 915 916
	 *  - 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
917 918 919 920
	 * 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.
921
	 *
922 923 924 925
	 * 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.
	 *
926 927
	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
928 929 930
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
931 932 933
	 */

	/*
934
	 * No point in finding a key and decrypting if the frame is neither
935 936
	 * addressed to us nor a multicast frame.
	 */
937
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
938
		return RX_CONTINUE;
939

940 941 942
	/* start without a key */
	rx->key = NULL;

943
	if (rx->sta)
944
		sta_ptk = rcu_dereference(rx->sta->ptk);
945

946 947 948
	fc = hdr->frame_control;

	if (!ieee80211_has_protected(fc))
949 950
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

951 952
	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
		rx->key = sta_ptk;
953 954 955
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
			return RX_CONTINUE;
956
		/* Skip decryption if the frame is not protected. */
957
		if (!ieee80211_has_protected(fc))
958
			return RX_CONTINUE;
959 960
	} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
Johannes Berg's avatar
Johannes Berg committed
961 962
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
963 964 965 966 967
			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 */
968 969 970 971
		if (rx->sta)
			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
		if (!rx->key)
			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
972
	} else if (!ieee80211_has_protected(fc)) {
973 974 975 976 977 978 979
		/*
		 * 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;
980 981 982
		struct ieee80211_sub_if_data *sdata = rx->sdata;
		int i;

983
		if (ieee80211_is_mgmt(fc) &&
984 985 986
		    is_multicast_ether_addr(hdr->addr1) &&
		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
			rx->key = key;
987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004
		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;
		}
1005
		return RX_CONTINUE;
1006
	} else {
1007
		u8 keyid;
1008 1009 1010 1011 1012 1013 1014 1015 1016
		/*
		 * 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
1017 1018
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
1019
			return RX_CONTINUE;
1020

1021
		hdrlen = ieee80211_hdrlen(fc);
1022 1023

		if (rx->skb->len < 8 + hdrlen)
Johannes Berg's avatar
Johannes Berg committed
1024
			return RX_DROP_UNUSABLE; /* TODO: count this? */
1025 1026 1027 1028 1029

		/*
		 * no need to call ieee80211_wep_get_keyidx,
		 * it verifies a bunch of things we've done already
		 */
1030 1031
		skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
		keyidx = keyid >> 6;
1032

1033 1034 1035
		/* 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]);
1036

1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
		/* 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;
		}
1052 1053
	}

1054
	if (rx->key) {
1055 1056 1057
		if (unlikely(rx->key->flags & KEY_FLAG_TAINTED))
			return RX_DROP_MONITOR;

1058
		rx->key->tx_rx_count++;
1059
		/* TODO: add threshold stuff again */
1060
	} else {
Johannes Berg's avatar
Johannes Berg committed
1061
		return RX_DROP_MONITOR;
1062 1063
	}

1064 1065
	if (skb_linearize(rx->skb))
		return RX_DROP_UNUSABLE;
1066
	/* the hdr variable is invalid now! */
1067

1068 1069 1070
	switch (rx->key->conf.cipher) {
	case WLAN_CIPHER_SUITE_WEP40:
	case WLAN_CIPHER_SUITE_WEP104:
1071 1072 1073 1074 1075 1076 1077
		/* Check for weak IVs if possible */
		if (rx->sta && ieee80211_is_data(fc) &&
		    (!(status->flag & RX_FLAG_IV_STRIPPED) ||
		     !(status->flag & RX_FLAG_DECRYPTED)) &&
		    ieee80211_wep_is_weak_iv(rx->skb