rx.c 95.1 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
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);

45 46
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
Zhu Yi's avatar
Zhu Yi committed
47
			__pskb_trim(skb, skb->len - FCS_LEN);
48 49 50 51
		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
52
			return NULL;
53 54 55
		}
	}

56 57 58
	if (status->vendor_radiotap_len)
		__pskb_pull(skb, status->vendor_radiotap_len);

59 60 61
	return skb;
}

62
static inline int should_drop_frame(struct sk_buff *skb, int present_fcs_len)
63
{
64
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
65 66 67
	struct ieee80211_hdr *hdr;

	hdr = (void *)(skb->data + status->vendor_radiotap_len);
68

69 70 71
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
			    RX_FLAG_FAILED_PLCP_CRC |
			    RX_FLAG_AMPDU_IS_ZEROLEN))
72
		return 1;
73 74
	if (unlikely(skb->len < 16 + present_fcs_len +
				status->vendor_radiotap_len))
75
		return 1;
76 77 78
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
79 80 81 82
		return 1;
	return 0;
}

83
static int
84 85
ieee80211_rx_radiotap_space(struct ieee80211_local *local,
			    struct ieee80211_rx_status *status)
86 87 88 89
{
	int len;

	/* always present fields */
90
	len = sizeof(struct ieee80211_radiotap_header) + 8;
91

92
	/* allocate extra bitmaps */
93 94
	if (status->vendor_radiotap_len)
		len += 4;
95 96
	if (status->chains)
		len += 4 * hweight8(status->chains);
97 98 99

	if (ieee80211_have_rx_timestamp(status)) {
		len = ALIGN(len, 8);
100
		len += 8;
101
	}
Johannes Berg's avatar
Johannes Berg committed
102
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
103 104
		len += 1;

105 106 107 108
	/* antenna field, if we don't have per-chain info */
	if (!status->chains)
		len += 1;

109 110
	/* padding for RX_FLAGS if necessary */
	len = ALIGN(len, 2);
111

112 113 114
	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

115
	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
116
		len = ALIGN(len, 4);
117 118 119
		len += 8;
	}

120 121 122 123 124
	if (status->flag & RX_FLAG_VHT) {
		len = ALIGN(len, 2);
		len += 12;
	}

125 126 127 128 129
	if (status->chains) {
		/* antenna and antenna signal fields */
		len += 2 * hweight8(status->chains);
	}

130 131 132 133 134 135 136 137 138 139 140 141
	if (status->vendor_radiotap_len) {
		if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
			status->vendor_radiotap_align = 1;
		/* align standard part of vendor namespace */
		len = ALIGN(len, 2);
		/* allocate standard part of vendor namespace */
		len += 6;
		/* align vendor-defined part */
		len = ALIGN(len, status->vendor_radiotap_align);
		/* vendor-defined part is already in skb */
	}

142 143 144
	return len;
}

145
/*
146 147 148 149 150 151 152 153
 * 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,
154
				 int rtap_len, bool has_fcs)
155
{
156
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
157 158
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
159 160
	__le32 *it_present;
	u32 it_present_val;
161
	u16 rx_flags = 0;
162
	u16 channel_flags = 0;
163 164
	int mpdulen, chain;
	unsigned long chains = status->chains;
165 166 167 168

	mpdulen = skb->len;
	if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
		mpdulen += FCS_LEN;
169 170 171

	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
	memset(rthdr, 0, rtap_len);
172
	it_present = &rthdr->it_present;
173 174

	/* radiotap header, set always present flags */
175
	rthdr->it_len = cpu_to_le16(rtap_len + status->vendor_radiotap_len);
176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
	it_present_val = BIT(IEEE80211_RADIOTAP_FLAGS) |
			 BIT(IEEE80211_RADIOTAP_CHANNEL) |
			 BIT(IEEE80211_RADIOTAP_RX_FLAGS);

	if (!status->chains)
		it_present_val |= BIT(IEEE80211_RADIOTAP_ANTENNA);

	for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
		it_present_val |=
			BIT(IEEE80211_RADIOTAP_EXT) |
			BIT(IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE);
		put_unaligned_le32(it_present_val, it_present);
		it_present++;
		it_present_val = BIT(IEEE80211_RADIOTAP_ANTENNA) |
				 BIT(IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
	}
192

193
	if (status->vendor_radiotap_len) {
194 195 196 197 198
		it_present_val |= BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE) |
				  BIT(IEEE80211_RADIOTAP_EXT);
		put_unaligned_le32(it_present_val, it_present);
		it_present++;
		it_present_val = status->vendor_radiotap_bitmap;
199 200
	}

201 202 203 204
	put_unaligned_le32(it_present_val, it_present);

	pos = (void *)(it_present + 1);

205 206 207
	/* the order of the following fields is important */

	/* IEEE80211_RADIOTAP_TSFT */
208
	if (ieee80211_have_rx_timestamp(status)) {
209 210 211
		/* padding */
		while ((pos - (u8 *)rthdr) & 7)
			*pos++ = 0;
212 213 214 215
		put_unaligned_le64(
			ieee80211_calculate_rx_timestamp(local, status,
							 mpdulen, 0),
			pos);
216
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
217 218 219 220
		pos += 8;
	}

	/* IEEE80211_RADIOTAP_FLAGS */
221
	if (has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS))
222
		*pos |= IEEE80211_RADIOTAP_F_FCS;
Johannes Berg's avatar
Johannes Berg committed
223 224
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
225 226
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
227 228 229
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
230
	if (!rate || status->flag & (RX_FLAG_HT | RX_FLAG_VHT)) {
231
		/*
232
		 * Without rate information don't add it. If we have,
233
		 * MCS information is a separate field in radiotap,
234 235
		 * added below. The byte here is needed as padding
		 * for the channel though, so initialise it to 0.
236 237
		 */
		*pos = 0;
238
	} else {
239
		int shift = 0;
240
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
241 242 243 244 245
		if (status->flag & RX_FLAG_10MHZ)
			shift = 1;
		else if (status->flag & RX_FLAG_5MHZ)
			shift = 2;
		*pos = DIV_ROUND_UP(rate->bitrate, 5 * (1 << shift));
246
	}
247 248 249
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
250
	put_unaligned_le16(status->freq, pos);
251
	pos += 2;
252 253 254 255 256
	if (status->flag & RX_FLAG_10MHZ)
		channel_flags |= IEEE80211_CHAN_HALF;
	else if (status->flag & RX_FLAG_5MHZ)
		channel_flags |= IEEE80211_CHAN_QUARTER;

257
	if (status->band == IEEE80211_BAND_5GHZ)
258
		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ;
259
	else if (status->flag & (RX_FLAG_HT | RX_FLAG_VHT))
260
		channel_flags |= IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ;
261
	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
262
		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ;
263
	else if (rate)
264
		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ;
265
	else
266 267
		channel_flags |= IEEE80211_CHAN_2GHZ;
	put_unaligned_le16(channel_flags, pos);
268 269 270
	pos += 2;

	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
271 272
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
	    !(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
273 274 275 276 277 278 279 280
		*pos = status->signal;
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
		pos++;
	}

	/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */

281 282 283 284 285
	if (!status->chains) {
		/* IEEE80211_RADIOTAP_ANTENNA */
		*pos = status->antenna;
		pos++;
	}
286 287 288 289 290

	/* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */

	/* IEEE80211_RADIOTAP_RX_FLAGS */
	/* ensure 2 byte alignment for the 2 byte field as required */
291
	if ((pos - (u8 *)rthdr) & 1)
292
		*pos++ = 0;
Johannes Berg's avatar
Johannes Berg committed
293
	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
294 295
		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
296
	pos += 2;
297 298

	if (status->flag & RX_FLAG_HT) {
299 300
		unsigned int stbc;

301
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
302
		*pos++ = local->hw.radiotap_mcs_details;
303 304 305 306 307
		*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;
308 309
		if (status->flag & RX_FLAG_HT_GF)
			*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
310 311
		stbc = (status->flag & RX_FLAG_STBC_MASK) >> RX_FLAG_STBC_SHIFT;
		*pos |= stbc << IEEE80211_RADIOTAP_MCS_STBC_SHIFT;
312 313 314
		pos++;
		*pos++ = status->rate_idx;
	}
315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345

	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
		u16 flags = 0;

		/* ensure 4 byte alignment */
		while ((pos - (u8 *)rthdr) & 3)
			pos++;
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_AMPDU_STATUS);
		put_unaligned_le32(status->ampdu_reference, pos);
		pos += 4;
		if (status->flag & RX_FLAG_AMPDU_REPORT_ZEROLEN)
			flags |= IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN;
		if (status->flag & RX_FLAG_AMPDU_IS_ZEROLEN)
			flags |= IEEE80211_RADIOTAP_AMPDU_IS_ZEROLEN;
		if (status->flag & RX_FLAG_AMPDU_LAST_KNOWN)
			flags |= IEEE80211_RADIOTAP_AMPDU_LAST_KNOWN;
		if (status->flag & RX_FLAG_AMPDU_IS_LAST)
			flags |= IEEE80211_RADIOTAP_AMPDU_IS_LAST;
		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_ERROR)
			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR;
		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN;
		put_unaligned_le16(flags, pos);
		pos += 2;
		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
			*pos++ = status->ampdu_delimiter_crc;
		else
			*pos++ = 0;
		*pos++ = 0;
	}
346

347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381
	if (status->flag & RX_FLAG_VHT) {
		u16 known = local->hw.radiotap_vht_details;

		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
		/* known field - how to handle 80+80? */
		if (status->flag & RX_FLAG_80P80MHZ)
			known &= ~IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
		put_unaligned_le16(known, pos);
		pos += 2;
		/* flags */
		if (status->flag & RX_FLAG_SHORT_GI)
			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
		pos++;
		/* bandwidth */
		if (status->flag & RX_FLAG_80MHZ)
			*pos++ = 4;
		else if (status->flag & RX_FLAG_80P80MHZ)
			*pos++ = 0; /* marked not known above */
		else if (status->flag & RX_FLAG_160MHZ)
			*pos++ = 11;
		else if (status->flag & RX_FLAG_40MHZ)
			*pos++ = 1;
		else /* 20 MHz */
			*pos++ = 0;
		/* MCS/NSS */
		*pos = (status->rate_idx << 4) | status->vht_nss;
		pos += 4;
		/* coding field */
		pos++;
		/* group ID */
		pos++;
		/* partial_aid */
		pos += 2;
	}

382 383 384 385 386
	for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
		*pos++ = status->chain_signal[chain];
		*pos++ = chain;
	}

387 388 389 390 391 392 393 394 395 396 397 398 399 400
	if (status->vendor_radiotap_len) {
		/* ensure 2 byte alignment for the vendor field as required */
		if ((pos - (u8 *)rthdr) & 1)
			*pos++ = 0;
		*pos++ = status->vendor_radiotap_oui[0];
		*pos++ = status->vendor_radiotap_oui[1];
		*pos++ = status->vendor_radiotap_oui[2];
		*pos++ = status->vendor_radiotap_subns;
		put_unaligned_le16(status->vendor_radiotap_len, pos);
		pos += 2;
		/* align the actual payload as requested */
		while ((pos - (u8 *)rthdr) & (status->vendor_radiotap_align - 1))
			*pos++ = 0;
	}
401 402
}

403 404 405 406 407 408 409
/*
 * 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,
410
		     struct ieee80211_rate *rate)
411
{
412
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
413
	struct ieee80211_sub_if_data *sdata;
414
	int needed_headroom;
415 416 417 418 419 420 421 422 423 424 425 426
	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.
	 */
427

428 429 430
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
		present_fcs_len = FCS_LEN;

431 432
	/* ensure hdr->frame_control and vendor radiotap data are in skb head */
	if (!pskb_may_pull(origskb, 2 + status->vendor_radiotap_len)) {
Zhu Yi's avatar
Zhu Yi committed
433 434 435 436
		dev_kfree_skb(origskb);
		return NULL;
	}

437
	if (!local->monitors) {
438
		if (should_drop_frame(origskb, present_fcs_len)) {
439 440 441 442
			dev_kfree_skb(origskb);
			return NULL;
		}

443
		return remove_monitor_info(local, origskb);
444 445
	}

446 447 448
	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_space(local, status);

449
	if (should_drop_frame(origskb, present_fcs_len)) {
450 451 452 453 454 455 456 457 458 459 460 461
		/* 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 &&
462
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
463 464 465 466 467 468 469 470 471 472
			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);

473
		origskb = remove_monitor_info(local, origskb);
474 475 476 477 478

		if (!skb)
			return origskb;
	}

479
	/* prepend radiotap information */
480 481
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
					 true);
482

483
	skb_reset_mac_header(skb);
484 485 486 487 488
	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) {
489
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
490 491
			continue;

492 493 494
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

495
		if (!ieee80211_sdata_running(sdata))
496 497
			continue;

498 499 500 501
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
502
				netif_receive_skb(skb2);
503 504 505 506 507 508 509 510 511 512
			}
		}

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

	if (prev_dev) {
		skb->dev = prev_dev;
513
		netif_receive_skb(skb);
514 515 516 517 518 519
	} else
		dev_kfree_skb(skb);

	return origskb;
}

520
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
521
{
522
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
523
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
524
	int tid, seqno_idx, security_idx;
525 526

	/* does the frame have a qos control field? */
527 528
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
529
		/* frame has qos control */
530
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
531
		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
532
			status->rx_flags |= IEEE80211_RX_AMSDU;
533 534 535

		seqno_idx = tid;
		security_idx = tid;
536
	} else {
537 538 539 540 541 542 543 544 545 546 547
		/*
		 * 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.
		 */
548
		seqno_idx = IEEE80211_NUM_TIDS;
549 550
		security_idx = 0;
		if (ieee80211_is_mgmt(hdr->frame_control))
551
			security_idx = IEEE80211_NUM_TIDS;
552
		tid = 0;
553
	}
554

555 556
	rx->seqno_idx = seqno_idx;
	rx->security_idx = security_idx;
557 558 559
	/* 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;
560
}
561

562 563 564 565 566 567 568 569 570 571 572
/**
 * 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
573 574 575
 * 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.
576 577 578 579 580 581 582
 *
 * 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
583
 * Padding like Atheros hardware adds which is between the 802.11 header and
584 585 586 587
 * 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)
588
{
589 590 591
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
592
#endif
593 594
}

595

596 597
/* rx handlers */

598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625
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;

626
	if (skb->len < 24 + sizeof(*mmie) || !is_multicast_ether_addr(hdr->da))
627 628 629 630 631 632 633 634 635 636 637 638 639 640
		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);
}

641
static ieee80211_rx_result ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
642
{
643
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
644
	char *dev_addr = rx->sdata->vif.addr;
645

646
	if (ieee80211_is_data(hdr->frame_control)) {
647 648
		if (is_multicast_ether_addr(hdr->addr1)) {
			if (ieee80211_has_tods(hdr->frame_control) ||
649
			    !ieee80211_has_fromds(hdr->frame_control))
650
				return RX_DROP_MONITOR;
651
			if (ether_addr_equal(hdr->addr3, dev_addr))
652 653 654 655
				return RX_DROP_MONITOR;
		} else {
			if (!ieee80211_has_a4(hdr->frame_control))
				return RX_DROP_MONITOR;
656
			if (ether_addr_equal(hdr->addr4, dev_addr))
657 658
				return RX_DROP_MONITOR;
		}
659 660 661 662 663 664
	}

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

665
	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
666
		struct ieee80211_mgmt *mgmt;
667

668
		if (!ieee80211_is_mgmt(hdr->frame_control))
669 670
			return RX_DROP_MONITOR;

671
		if (ieee80211_is_action(hdr->frame_control)) {
672
			u8 category;
673 674 675 676 677

			/* make sure category field is present */
			if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE)
				return RX_DROP_MONITOR;

678
			mgmt = (struct ieee80211_mgmt *)hdr;
679 680
			category = mgmt->u.action.category;
			if (category != WLAN_CATEGORY_MESH_ACTION &&
681
			    category != WLAN_CATEGORY_SELF_PROTECTED)
682 683 684 685
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

686 687
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
688 689
		    ieee80211_is_beacon(hdr->frame_control) ||
		    ieee80211_is_auth(hdr->frame_control))
690 691 692 693 694
			return RX_CONTINUE;

		return RX_DROP_MONITOR;
	}

Johannes Berg's avatar
Johannes Berg committed
695 696
	return RX_CONTINUE;
}
697

698
static void ieee80211_release_reorder_frame(struct ieee80211_sub_if_data *sdata,
699
					    struct tid_ampdu_rx *tid_agg_rx,
700 701
					    int index,
					    struct sk_buff_head *frames)
702 703
{
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
704
	struct ieee80211_rx_status *status;
705

706 707
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

708 709 710
	if (!skb)
		goto no_frame;

711
	/* release the frame from the reorder ring buffer */
712 713
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
714 715
	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
716
	__skb_queue_tail(frames, skb);
717 718

no_frame:
719
	tid_agg_rx->head_seq_num = ieee80211_sn_inc(tid_agg_rx->head_seq_num);
720 721
}

722
static void ieee80211_release_reorder_frames(struct ieee80211_sub_if_data *sdata,
723
					     struct tid_ampdu_rx *tid_agg_rx,
724 725
					     u16 head_seq_num,
					     struct sk_buff_head *frames)
726 727 728
{
	int index;

729 730
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

731
	while (ieee80211_sn_less(tid_agg_rx->head_seq_num, head_seq_num)) {
732
		index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
733 734
		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
						frames);
735 736 737 738 739 740 741 742 743
	}
}

/*
 * 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.
744 745
 *
 * Callers must hold tid_agg_rx->reorder_lock.
746 747 748
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

749
static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata,
750 751
					  struct tid_ampdu_rx *tid_agg_rx,
					  struct sk_buff_head *frames)
752
{
753
	int index, j;
754

755 756
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

757
	/* release the buffer until next missing frame */
758
	index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
759
	if (!tid_agg_rx->reorder_buf[index] &&
760
	    tid_agg_rx->stored_mpdu_num) {
761 762 763 764 765 766 767 768 769 770 771
		/*
		 * 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;
			}
772 773
			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
774
					HT_RX_REORDER_BUF_TIMEOUT))
775
				goto set_release_timer;
776

Johannes Berg's avatar
Johannes Berg committed
777 778
			ht_dbg_ratelimited(sdata,
					   "release an RX reorder frame due to timeout on earlier frames\n");
779 780
			ieee80211_release_reorder_frame(sdata, tid_agg_rx, j,
							frames);
781 782 783 784 785

			/*
			 * Increment the head seq# also for the skipped slots.
			 */
			tid_agg_rx->head_seq_num =
786 787
				(tid_agg_rx->head_seq_num +
				 skipped) & IEEE80211_SN_MASK;
788 789 790
			skipped = 0;
		}
	} else while (tid_agg_rx->reorder_buf[index]) {
791 792
		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
						frames);
793
		index =	tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
794
	}
795 796

	if (tid_agg_rx->stored_mpdu_num) {
797
		j = index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
798 799 800 801 802 803 804 805 806 807

		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,
808
			  tid_agg_rx->reorder_time[j] + 1 +
809 810 811 812
			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
813 814
}

815 816 817 818 819
/*
 * 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.
 */
820
static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata,
821
					     struct tid_ampdu_rx *tid_agg_rx,
822 823
					     struct sk_buff *skb,
					     struct sk_buff_head *frames)
824 825 826 827 828 829
{
	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;
830
	bool ret = true;
831

832 833
	spin_lock(&tid_agg_rx->reorder_lock);

834 835 836 837
	buf_size = tid_agg_rx->buf_size;
	head_seq_num = tid_agg_rx->head_seq_num;

	/* frame with out of date sequence number */
838
	if (ieee80211_sn_less(mpdu_seq_num, head_seq_num)) {
839
		dev_kfree_skb(skb);
840
		goto out;
841 842 843 844 845 846
	}

	/*
	 * If frame the sequence number exceeds our buffering window
	 * size release some previous frames to make room for this one.
	 */
847 848 849
	if (!ieee80211_sn_less(mpdu_seq_num, head_seq_num + buf_size)) {
		head_seq_num = ieee80211_sn_inc(
				ieee80211_sn_sub(mpdu_seq_num, buf_size));
850
		/* release stored frames up to new head to stack */
851
		ieee80211_release_reorder_frames(sdata, tid_agg_rx,
852
						 head_seq_num, frames);
853 854 855 856
	}

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

857
	index = mpdu_seq_num % tid_agg_rx->buf_size;
858 859 860 861

	/* check if we already stored this frame */
	if (tid_agg_rx->reorder_buf[index]) {
		dev_kfree_skb(skb);
862
		goto out;
863 864 865 866 867
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
868 869
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
870 871 872
	 */
	if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
	    tid_agg_rx->stored_mpdu_num == 0) {
873 874
		tid_agg_rx->head_seq_num =
			ieee80211_sn_inc(tid_agg_rx->head_seq_num);
875 876
		ret = false;
		goto out;
877 878 879 880 881 882
	}

	/* 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++;
883
	ieee80211_sta_reorder_release(sdata, tid_agg_rx, frames);
884

885 886 887
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
888 889 890 891 892 893
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
894 895
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
				       struct sk_buff_head *frames)
896
{
897 898
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
899
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
900
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
901
	struct sta_info *sta = rx->sta;
902 903
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
904
	u8 tid, ack_policy;
905 906

	if (!ieee80211_is_data_qos(hdr->frame_control))
907
		goto dont_reorder;
908 909 910 911 912 913 914

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

	if (!sta)
915
		goto dont_reorder;
916

917 918
	ack_policy = *ieee80211_get_qos_ctl(hdr) &
		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
919 920
	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

921 922 923
	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
924 925 926

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
927
		goto dont_reorder;
928

929 930 931 932 933
	/* 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;

934 935 936 937
	/* not actually part of this BA session */
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
		goto dont_reorder;

938 939 940 941
	/* new, potentially un-ordered, ampdu frame - process it */

	/* reset session timer */
	if (tid_agg_rx->timeout)
942
		tid_agg_rx->last_rx = jiffies;
943 944 945 946

	/* if this mpdu is fragmented - terminate rx aggregation session */
	sc = le16_to_cpu(hdr->seq_ctrl);
	if (sc & IEEE80211_SCTL_FRAG) {
947
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
948 949
		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
950
		return;
951 952
	}

953 954 955 956 957 958 959
	/*
	 * 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.
	 */
960 961
	if (ieee80211_sta_manage_reorder_buf(rx->sdata, tid_agg_rx, skb,
					     frames))
962 963 964
		return;

 dont_reorder:
965
	__skb_queue_tail(frames, skb);
966
}
967

968
static ieee80211_rx_result debug_noinline
969
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
970
{
971
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
972
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
973

974 975 976 977 978 979 980 981
	/*
	 * Drop duplicate 802.11 retransmissions
	 * (IEEE 802.11-2012: 9.3.2.10 "Duplicate detection and recovery")
	 */
	if (rx->skb->len >= 24 && rx->sta &&
	    !ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_qos_nullfunc(hdr->frame_control) &&
	    !is_multicast_ether_addr(hdr->addr1)) {
982
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
983
			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
984
			     hdr->seq_ctrl)) {
985
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
986 987 988
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
989
			return RX_DROP_UNUSABLE;
990
		} else if (!(status->flag & RX_FLAG_AMSDU_MORE)) {
991
			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
992
		}
993 994 995 996
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
997
		return RX_DROP_MONITOR;
998 999 1000 1001 1002
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
1003 1004
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
1005 1006 1007
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
1008

Johannes Berg's avatar
Johannes Berg committed
1009
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
1010 1011
		return ieee80211_rx_mesh_check(rx);

1012 1013
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
1014
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
Bill Jordan's avatar
Bill Jordan committed
1015
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
1016
		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
1017 1018