rx.c 86.6 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, 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 64
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
			    RX_FLAG_FAILED_PLCP_CRC |
			    RX_FLAG_AMPDU_IS_ZEROLEN))
65
		return 1;
66
	if (unlikely(skb->len < 16 + present_fcs_len))
67
		return 1;
68 69 70
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
71 72 73 74
		return 1;
	return 0;
}

75 76 77 78 79 80 81 82 83
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
84
	if (status->flag & RX_FLAG_MACTIME_MPDU)
85
		len += 8;
Johannes Berg's avatar
Johannes Berg committed
86
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
87 88 89 90 91
		len += 1;

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

92 93 94
	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

95 96 97 98 99 100 101
	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
		/* padding */
		while (len & 3)
			len++;
		len += 8;
	}

102 103 104
	return len;
}

105
/*
106 107 108 109 110 111 112 113
 * 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,
114
				 int rtap_len, bool has_fcs)
115
{
116
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
117 118
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
119
	u16 rx_flags = 0;
120 121 122 123 124 125 126 127 128 129 130 131

	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);

132
	pos = (unsigned char *)(rthdr + 1);
133 134 135 136

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

	/* IEEE80211_RADIOTAP_TSFT */
Johannes Berg's avatar
Johannes Berg committed
137
	if (status->flag & RX_FLAG_MACTIME_MPDU) {
138
		put_unaligned_le64(status->mactime, pos);
139
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
140 141 142 143
		pos += 8;
	}

	/* IEEE80211_RADIOTAP_FLAGS */
144
	if (has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS))
145
		*pos |= IEEE80211_RADIOTAP_F_FCS;
Johannes Berg's avatar
Johannes Berg committed
146 147
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
148 149
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
150 151 152
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
153
	if (!rate || status->flag & RX_FLAG_HT) {
154
		/*
155
		 * Without rate information don't add it. If we have,
156
		 * MCS information is a separate field in radiotap,
157 158
		 * added below. The byte here is needed as padding
		 * for the channel though, so initialise it to 0.
159 160
		 */
		*pos = 0;
161
	} else {
162
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
163
		*pos = rate->bitrate / 5;
164
	}
165 166 167
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
168
	put_unaligned_le16(status->freq, pos);
169 170
	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
171 172
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
173 174 175
	else if (status->flag & RX_FLAG_HT)
		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
176
	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
177 178
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
179
	else if (rate)
180 181
		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
182 183
	else
		put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
184 185 186
	pos += 2;

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

	if (status->flag & RX_FLAG_HT) {
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
214
		*pos++ = local->hw.radiotap_mcs_details;
215 216 217 218 219
		*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;
220 221
		if (status->flag & RX_FLAG_HT_GF)
			*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
222 223 224
		pos++;
		*pos++ = status->rate_idx;
	}
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255

	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;
	}
256 257
}

258 259 260 261 262 263 264
/*
 * 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,
265
		     struct ieee80211_rate *rate)
266
{
267
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
268
	struct ieee80211_sub_if_data *sdata;
269
	int needed_headroom;
270 271 272 273 274 275 276 277 278 279 280 281
	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.
	 */
282 283 284

	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_len(local, status);
285 286 287 288

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

Zhu Yi's avatar
Zhu Yi committed
289 290 291 292 293 294
	/* make sure hdr->frame_control is on the linear part */
	if (!pskb_may_pull(origskb, 2)) {
		dev_kfree_skb(origskb);
		return NULL;
	}

295
	if (!local->monitors) {
296
		if (should_drop_frame(origskb, present_fcs_len)) {
297 298 299 300
			dev_kfree_skb(origskb);
			return NULL;
		}

301
		return remove_monitor_info(local, origskb);
302 303
	}

304
	if (should_drop_frame(origskb, present_fcs_len)) {
305 306 307 308 309 310 311 312 313 314 315 316
		/* 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 &&
317
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
318 319 320 321 322 323 324 325 326 327
			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);

328
		origskb = remove_monitor_info(local, origskb);
329 330 331 332 333

		if (!skb)
			return origskb;
	}

334
	/* prepend radiotap information */
335 336
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
					 true);
337

338
	skb_reset_mac_header(skb);
339 340 341 342 343
	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) {
344
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
345 346
			continue;

347 348 349
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

350
		if (!ieee80211_sdata_running(sdata))
351 352
			continue;

353 354 355 356
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
357
				netif_receive_skb(skb2);
358 359 360 361 362 363 364 365 366 367
			}
		}

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

	if (prev_dev) {
		skb->dev = prev_dev;
368
		netif_receive_skb(skb);
369 370 371 372 373 374
	} else
		dev_kfree_skb(skb);

	return origskb;
}

375
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
376
{
377
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
378
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
379
	int tid, seqno_idx, security_idx;
380 381

	/* does the frame have a qos control field? */
382 383
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
384
		/* frame has qos control */
385
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
386
		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
387
			status->rx_flags |= IEEE80211_RX_AMSDU;
388 389 390

		seqno_idx = tid;
		security_idx = tid;
391
	} else {
392 393 394 395 396 397 398 399 400 401 402
		/*
		 * 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.
		 */
403 404 405 406 407
		seqno_idx = NUM_RX_DATA_QUEUES;
		security_idx = 0;
		if (ieee80211_is_mgmt(hdr->frame_control))
			security_idx = NUM_RX_DATA_QUEUES;
		tid = 0;
408
	}
409

410 411
	rx->seqno_idx = seqno_idx;
	rx->security_idx = security_idx;
412 413 414
	/* 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;
415
}
416

417 418 419 420 421 422 423 424 425 426 427
/**
 * 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
428 429 430
 * 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.
431 432 433 434 435 436 437
 *
 * 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
438
 * Padding like Atheros hardware adds which is between the 802.11 header and
439 440 441 442
 * 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)
443
{
444 445 446
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
447
#endif
448 449
}

450

451 452
/* rx handlers */

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
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;

481
	if (skb->len < 24 + sizeof(*mmie) || !is_multicast_ether_addr(hdr->da))
482 483 484 485 486 487 488 489 490 491 492 493 494 495
		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);
}

496
static ieee80211_rx_result ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
497
{
498
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
499
	char *dev_addr = rx->sdata->vif.addr;
500

501
	if (ieee80211_is_data(hdr->frame_control)) {
502 503
		if (is_multicast_ether_addr(hdr->addr1)) {
			if (ieee80211_has_tods(hdr->frame_control) ||
504
			    !ieee80211_has_fromds(hdr->frame_control))
505
				return RX_DROP_MONITOR;
506
			if (ether_addr_equal(hdr->addr3, dev_addr))
507 508 509 510
				return RX_DROP_MONITOR;
		} else {
			if (!ieee80211_has_a4(hdr->frame_control))
				return RX_DROP_MONITOR;
511
			if (ether_addr_equal(hdr->addr4, dev_addr))
512 513
				return RX_DROP_MONITOR;
		}
514 515 516 517 518 519
	}

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

520
	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
521
		struct ieee80211_mgmt *mgmt;
522

523
		if (!ieee80211_is_mgmt(hdr->frame_control))
524 525
			return RX_DROP_MONITOR;

526
		if (ieee80211_is_action(hdr->frame_control)) {
527
			u8 category;
528 529 530 531 532

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

533
			mgmt = (struct ieee80211_mgmt *)hdr;
534 535
			category = mgmt->u.action.category;
			if (category != WLAN_CATEGORY_MESH_ACTION &&
536
			    category != WLAN_CATEGORY_SELF_PROTECTED)
537 538 539 540
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

541 542
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
543 544
		    ieee80211_is_beacon(hdr->frame_control) ||
		    ieee80211_is_auth(hdr->frame_control))
545 546 547 548 549
			return RX_CONTINUE;

		return RX_DROP_MONITOR;
	}

Johannes Berg's avatar
Johannes Berg committed
550 551
	return RX_CONTINUE;
}
552

553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570
#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;
}

571
static void ieee80211_release_reorder_frame(struct ieee80211_sub_if_data *sdata,
572
					    struct tid_ampdu_rx *tid_agg_rx,
573
					    int index)
574
{
575
	struct ieee80211_local *local = sdata->local;
576
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
577
	struct ieee80211_rx_status *status;
578

579 580
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

581 582 583
	if (!skb)
		goto no_frame;

584
	/* release the frame from the reorder ring buffer */
585 586
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
587 588
	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
589
	skb_queue_tail(&local->rx_skb_queue, skb);
590 591 592 593 594

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

595
static void ieee80211_release_reorder_frames(struct ieee80211_sub_if_data *sdata,
596
					     struct tid_ampdu_rx *tid_agg_rx,
597
					     u16 head_seq_num)
598 599 600
{
	int index;

601 602
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

603 604 605
	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;
606
		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index);
607 608 609 610 611 612 613 614 615
	}
}

/*
 * 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.
616 617
 *
 * Callers must hold tid_agg_rx->reorder_lock.
618 619 620
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

621
static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata,
622
					  struct tid_ampdu_rx *tid_agg_rx)
623
{
624
	int index, j;
625

626 627
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

628 629 630 631
	/* 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] &&
632
	    tid_agg_rx->stored_mpdu_num) {
633 634 635 636 637 638 639 640 641 642 643
		/*
		 * 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;
			}
644 645
			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
646
					HT_RX_REORDER_BUF_TIMEOUT))
647
				goto set_release_timer;
648

Johannes Berg's avatar
Johannes Berg committed
649 650
			ht_dbg_ratelimited(sdata,
					   "release an RX reorder frame due to timeout on earlier frames\n");
651
			ieee80211_release_reorder_frame(sdata, tid_agg_rx, j);
652 653 654 655 656 657 658 659 660

			/*
			 * 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]) {
661
		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index);
662 663 664
		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}
665 666 667 668 669 670 671 672 673 674 675 676 677 678

	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,
679
			  tid_agg_rx->reorder_time[j] + 1 +
680 681 682 683
			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
684 685
}

686 687 688 689 690
/*
 * 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.
 */
691
static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata,
692
					     struct tid_ampdu_rx *tid_agg_rx,
693
					     struct sk_buff *skb)
694 695 696 697 698 699
{
	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;
700
	bool ret = true;
701

702 703
	spin_lock(&tid_agg_rx->reorder_lock);

704 705 706 707 708 709
	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);
710
		goto out;
711 712 713 714 715 716 717 718 719
	}

	/*
	 * 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 */
720 721
		ieee80211_release_reorder_frames(sdata, tid_agg_rx,
						 head_seq_num);
722 723 724 725 726 727 728 729 730
	}

	/* 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);
731
		goto out;
732 733 734 735 736
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
737 738
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
739 740 741 742
	 */
	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);
743 744
		ret = false;
		goto out;
745 746 747 748 749 750
	}

	/* 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++;
751
	ieee80211_sta_reorder_release(sdata, tid_agg_rx);
752

753 754 755
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
756 757 758 759 760 761
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
762
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
763
{
764 765
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
766
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
767
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
768
	struct sta_info *sta = rx->sta;
769 770
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
771
	u8 tid, ack_policy;
772 773

	if (!ieee80211_is_data_qos(hdr->frame_control))
774
		goto dont_reorder;
775 776 777 778 779 780 781

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

	if (!sta)
782
		goto dont_reorder;
783

784 785
	ack_policy = *ieee80211_get_qos_ctl(hdr) &
		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
786 787
	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

788 789 790
	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
791 792 793

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
794
		goto dont_reorder;
795

796 797 798 799 800
	/* 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;

801 802 803 804
	/* not actually part of this BA session */
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
		goto dont_reorder;

805 806 807 808
	/* new, potentially un-ordered, ampdu frame - process it */

	/* reset session timer */
	if (tid_agg_rx->timeout)
809
		tid_agg_rx->last_rx = jiffies;
810 811 812 813

	/* if this mpdu is fragmented - terminate rx aggregation session */
	sc = le16_to_cpu(hdr->seq_ctrl);
	if (sc & IEEE80211_SCTL_FRAG) {
814
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
815 816
		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
817
		return;
818 819
	}

820 821 822 823 824 825 826
	/*
	 * 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.
	 */
827
	if (ieee80211_sta_manage_reorder_buf(rx->sdata, tid_agg_rx, skb))
828 829 830
		return;

 dont_reorder:
831
	skb_queue_tail(&local->rx_skb_queue, skb);
832
}
833

834
static ieee80211_rx_result debug_noinline
835
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
836
{
837
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
838
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
839 840 841

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
842
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
843
			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
844
			     hdr->seq_ctrl)) {
845
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
846 847 848
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
849
			return RX_DROP_UNUSABLE;
850
		} else
851
			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
852 853 854 855
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
856
		return RX_DROP_MONITOR;
857 858 859 860 861
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
862 863
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
864 865 866
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
867

Johannes Berg's avatar
Johannes Berg committed
868
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
869 870
		return ieee80211_rx_mesh_check(rx);

871 872
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
873
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
Bill Jordan's avatar
Bill Jordan committed
874
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
875
		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
876 877 878 879 880 881
		/*
		 * 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 &&
882
		    ieee80211_is_data_present(hdr->frame_control)) {
883 884 885 886 887 888 889 890 891 892
			unsigned int hdrlen;
			__be16 ethertype;

			hdrlen = ieee80211_hdrlen(hdr->frame_control);

			if (rx->skb->len < hdrlen + 8)
				return RX_DROP_MONITOR;

			skb_copy_bits(rx->skb, hdrlen + 6, &ethertype, 2);
			if (ethertype == rx->sdata->control_port_protocol)
893 894
				return RX_CONTINUE;
		}
895 896 897 898 899 900 901

		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
902
		return RX_DROP_MONITOR;
903
	}
904

905
	return RX_CONTINUE;
906 907 908
}


909
static ieee80211_rx_result debug_noinline
910
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
911
{
Johannes Berg's avatar
Johannes Berg committed
912 913 914
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
915 916
	int keyidx;
	int hdrlen;
Johannes Berg's avatar
Johannes Berg committed
917
	ieee80211_rx_result result = RX_DROP_UNUSABLE;
918
	struct ieee80211_key *sta_ptk = NULL;
919
	int mmie_keyidx = -1;
920
	__le16 fc;
921

922 923 924
	/*
	 * Key selection 101
	 *
925
	 * There are four types of keys:
926
	 *  - GTK (group keys)
927
	 *  - IGTK (group keys for management frames)
928 929 930 931 932
	 *  - 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
933 934 935 936
	 * 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.
937
	 *
938 939 940 941
	 * 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.
	 *
942 943
	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
944 945 946
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
947 948 949
	 */

	/*
950
	 * No point in finding a key and decrypting if the frame is neither
951 952
	 * addressed to us nor a multicast frame.
	 */
953
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
954
		return RX_CONTINUE;
955

956 957 958
	/* start without a key */
	rx->key = NULL;

959
	if (rx->sta)
960
		sta_ptk = rcu_dereference(rx->sta->ptk);
961

962 963 964
	fc = hdr->frame_control;

	if (!ieee80211_has_protected(fc))
965 966
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

967 968
	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
		rx->key = sta_ptk;
969 970 971
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
			return RX_CONTINUE;
972
		/* Skip decryption if the frame is not protected. */
973
		if (!ieee80211_has_protected(fc))
974
			return RX_CONTINUE;
975 976
	} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
Johannes Berg's avatar
Johannes Berg committed
977 978
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
979 980 981 982 983
			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 */
984 985 986 987
		if (rx->sta)
			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
		if (!rx->key)
			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
988
	} else if (!ieee80211_has_protected(fc)) {
989 990 991 992 993 994 995
		/*
		 * 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;
996 997 998
		struct ieee80211_sub_if_data *sdata = rx->sdata;
		int i;

999
		if (ieee80211_is_mgmt(fc) &&
1000 1001 1002
		    is_multicast_ether_addr(hdr->addr1) &&
		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
			rx->key = key;
1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
		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;
		}
1021
		return RX_CONTINUE;
1022
	} else {
1023
		u8 keyid;
1024 1025 1026 1027 1028 1029 1030 1031 1032
		/*
		 * 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
1033 1034
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
1035
			return RX_CONTINUE;
1036

1037
		hdrlen = ieee80211_hdrlen(fc);
1038 1039

		if (rx->skb->len < 8 + hdrlen)
Johannes Berg's avatar
Johannes Berg committed
1040
			return RX_DROP_UNUSABLE; /* TODO: count this? */
1041 1042 1043 1044 1045

		/*
		 * no need to call ieee80211_wep_get_keyidx,
		 * it verifies a bunch of things we've done already
		 */