rx.c 81.4 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 20 21 22
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>

#include "ieee80211_i.h"
23
#include "driver-ops.h"
Johannes Berg's avatar
Johannes Berg committed
24
#include "led.h"
25
#include "mesh.h"
26 27 28 29 30
#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"

31 32 33 34 35 36 37
/*
 * 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,
38
					   struct sk_buff *skb)
39 40 41
{
	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
Zhu Yi's avatar
Zhu Yi committed
42
			__pskb_trim(skb, skb->len - FCS_LEN);
43 44 45 46 47 48 49 50 51 52 53
		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
			skb = NULL;
		}
	}

	return skb;
}

54
static inline int should_drop_frame(struct sk_buff *skb,
55
				    int present_fcs_len)
56
{
57
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
58
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
59 60 61

	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		return 1;
62
	if (unlikely(skb->len < 16 + present_fcs_len))
63
		return 1;
64 65 66
	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
67 68 69 70
		return 1;
	return 0;
}

71 72 73 74 75 76 77 78 79
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
80
	if (status->flag & RX_FLAG_MACTIME_MPDU)
81
		len += 8;
Johannes Berg's avatar
Johannes Berg committed
82
	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
83 84 85 86 87
		len += 1;

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

88 89 90
	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

91 92 93
	return len;
}

94
/*
95 96 97 98 99 100 101 102 103 104
 * 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)
{
105
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
106 107
	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
108
	u16 rx_flags = 0;
109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125

	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
126
	if (status->flag & RX_FLAG_MACTIME_MPDU) {
127
		put_unaligned_le64(status->mactime, pos);
128 129 130 131 132 133 134 135
		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
136 137
	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
138 139
	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
140 141 142
	pos++;

	/* IEEE80211_RADIOTAP_RATE */
143 144
	if (status->flag & RX_FLAG_HT) {
		/*
145 146
		 * MCS information is a separate field in radiotap,
		 * added below.
147 148
		 */
		*pos = 0;
149
	} else {
150
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
151
		*pos = rate->bitrate / 5;
152
	}
153 154 155
	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
156
	put_unaligned_le16(status->freq, pos);
157 158
	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
159 160
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
161 162 163
	else if (status->flag & RX_FLAG_HT)
		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
164
	else if (rate->flags & IEEE80211_RATE_ERP_G)
165 166
		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
167
	else
168 169
		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189
	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 */
190
	if ((pos - (u8 *)rthdr) & 1)
191
		pos++;
Johannes Berg's avatar
Johannes Berg committed
192
	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
193 194
		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
195
	pos += 2;
196 197 198 199 200 201 202 203 204 205 206 207 208 209

	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;
	}
210 211
}

212 213 214 215 216 217 218
/*
 * 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,
219
		     struct ieee80211_rate *rate)
220
{
221
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
222 223 224 225 226 227 228 229 230 231 232 233 234 235
	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.
	 */
236 237 238

	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_len(local, status);
239 240 241 242

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

Zhu Yi's avatar
Zhu Yi committed
243 244 245 246 247 248
	/* make sure hdr->frame_control is on the linear part */
	if (!pskb_may_pull(origskb, 2)) {
		dev_kfree_skb(origskb);
		return NULL;
	}

249
	if (!local->monitors) {
250
		if (should_drop_frame(origskb, present_fcs_len)) {
251 252 253 254
			dev_kfree_skb(origskb);
			return NULL;
		}

255
		return remove_monitor_info(local, origskb);
256 257
	}

258
	if (should_drop_frame(origskb, present_fcs_len)) {
259 260 261 262 263 264 265 266 267 268 269 270
		/* 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 &&
271
		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
272 273 274 275 276 277 278 279 280 281
			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);

282
		origskb = remove_monitor_info(local, origskb);
283 284 285 286 287

		if (!skb)
			return origskb;
	}

288 289
	/* prepend radiotap information */
	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
290

291
	skb_reset_mac_header(skb);
292 293 294 295 296
	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) {
297
		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
298 299
			continue;

300 301 302
		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
			continue;

303
		if (!ieee80211_sdata_running(sdata))
304 305
			continue;

306 307 308 309
		if (prev_dev) {
			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (skb2) {
				skb2->dev = prev_dev;
310
				netif_receive_skb(skb2);
311 312 313 314 315 316 317 318 319 320
			}
		}

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

	if (prev_dev) {
		skb->dev = prev_dev;
321
		netif_receive_skb(skb);
322 323 324 325 326 327 328
	} else
		dev_kfree_skb(skb);

	return origskb;
}


329
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
330
{
331
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
332
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
333 334 335
	int tid;

	/* does the frame have a qos control field? */
336 337
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
338
		/* frame has qos control */
339 340
		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
		if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
341
			status->rx_flags |= IEEE80211_RX_AMSDU;
342
	} else {
343 344 345 346 347 348 349 350 351 352 353 354
		/*
		 * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
		 *
		 *	Sequence numbers for management frames, QoS data
		 *	frames with a broadcast/multicast address in the
		 *	Address 1 field, and all non-QoS data frames sent
		 *	by QoS STAs are assigned using an additional single
		 *	modulo-4096 counter, [...]
		 *
		 * We also use that counter for non-QoS STAs.
		 */
		tid = NUM_RX_DATA_QUEUES - 1;
355
	}
356

357
	rx->queue = tid;
358 359 360
	/* 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;
361
}
362

363 364 365 366 367 368 369 370 371 372 373
/**
 * 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
374 375 376
 * 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.
377 378 379 380 381 382 383 384 385 386 387 388
 *
 * With A-MSDU frames, however, the payload data address must yield two modulo
 * four because there are 14-byte 802.3 headers within the A-MSDU frames that
 * push the IP header further back to a multiple of four again. Thankfully, the
 * specs were sane enough this time around to require padding each A-MSDU
 * subframe to a length that is a multiple of four.
 *
 * Padding like Atheros hardware adds which is inbetween the 802.11 header and
 * the payload is not supported, the driver is required to move the 802.11
 * header to be directly in front of the payload in that case.
 */
static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
389
{
390 391 392
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
393
#endif
394 395
}

396

397 398
/* rx handlers */

399
static ieee80211_rx_result debug_noinline
400
ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
401 402
{
	struct ieee80211_local *local = rx->local;
403
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
404 405
	struct sk_buff *skb = rx->skb;

406
	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN)))
407 408
		return RX_CONTINUE;

409 410
	if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
	    test_bit(SCAN_SW_SCANNING, &local->scanning))
411
		return ieee80211_scan_rx(rx->sdata, skb);
Zhu Yi's avatar
Zhu Yi committed
412

413 414 415
	/* scanning finished during invoking of handlers */
	I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
	return RX_DROP_UNUSABLE;
416 417
}

418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463

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);
}


464
static ieee80211_rx_result
465
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
466
{
467 468
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
	unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
469
	char *dev_addr = rx->sdata->vif.addr;
470

471
	if (ieee80211_is_data(hdr->frame_control)) {
472 473 474 475 476 477 478 479 480 481 482 483
		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;
		}
484 485 486 487 488 489
	}

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

490
	if (!rx->sta || sta_plink_state(rx->sta) != PLINK_ESTAB) {
491
		struct ieee80211_mgmt *mgmt;
492

493
		if (!ieee80211_is_mgmt(hdr->frame_control))
494 495
			return RX_DROP_MONITOR;

496
		if (ieee80211_is_action(hdr->frame_control)) {
497
			mgmt = (struct ieee80211_mgmt *)hdr;
498
			if (mgmt->u.action.category != WLAN_CATEGORY_MESH_PLINK)
499 500 501 502
				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

503 504 505 506 507 508 509 510 511 512 513 514 515
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
		    ieee80211_is_beacon(hdr->frame_control))
			return RX_CONTINUE;

		return RX_DROP_MONITOR;

	}

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

	if (ieee80211_is_data(hdr->frame_control) &&
	    is_multicast_ether_addr(hdr->addr1) &&
516
	    mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
517
		return RX_DROP_MONITOR;
Johannes Berg's avatar
Johannes Berg committed
518
#undef msh_h_get
519

Johannes Berg's avatar
Johannes Berg committed
520 521
	return RX_CONTINUE;
}
522

523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543
#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,
544
					    int index)
545
{
546
	struct ieee80211_local *local = hw_to_local(hw);
547
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
548
	struct ieee80211_rx_status *status;
549

550 551
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

552 553 554
	if (!skb)
		goto no_frame;

555
	/* release the frame from the reorder ring buffer */
556 557
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
558 559
	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
560
	skb_queue_tail(&local->rx_skb_queue, skb);
561 562 563 564 565 566 567

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,
568
					     u16 head_seq_num)
569 570 571
{
	int index;

572 573
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

574 575 576
	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;
577
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
578 579 580 581 582 583 584 585 586
	}
}

/*
 * 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.
587 588
 *
 * Callers must hold tid_agg_rx->reorder_lock.
589 590 591
 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

592
static void ieee80211_sta_reorder_release(struct ieee80211_hw *hw,
593
					  struct tid_ampdu_rx *tid_agg_rx)
594
{
595
	int index, j;
596

597 598
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614
	/* release the buffer until next missing frame */
	index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
						tid_agg_rx->buf_size;
	if (!tid_agg_rx->reorder_buf[index] &&
	    tid_agg_rx->stored_mpdu_num > 1) {
		/*
		 * No buffers ready to be released, but check whether any
		 * frames in the reorder buffer have timed out.
		 */
		int 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;
			}
615 616
			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
617
					HT_RX_REORDER_BUF_TIMEOUT))
618
				goto set_release_timer;
619 620 621

#ifdef CONFIG_MAC80211_HT_DEBUG
			if (net_ratelimit())
Joe Perches's avatar
Joe Perches committed
622 623
				wiphy_debug(hw->wiphy,
					    "release an RX reorder frame due to timeout on earlier frames\n");
624
#endif
625
			ieee80211_release_reorder_frame(hw, tid_agg_rx, j);
626 627 628 629 630 631 632 633 634

			/*
			 * 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]) {
635
		ieee80211_release_reorder_frame(hw, tid_agg_rx, index);
636 637 638
		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}
639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657

	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,
			  tid_agg_rx->reorder_time[j] +
			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
658 659
}

660 661 662 663 664 665 666
/*
 * 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,
667
					     struct sk_buff *skb)
668 669 670 671 672 673
{
	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;
674
	bool ret = true;
675

676 677
	spin_lock(&tid_agg_rx->reorder_lock);

678 679 680 681 682 683
	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);
684
		goto out;
685 686 687 688 689 690 691 692 693
	}

	/*
	 * 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 */
694
		ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num);
695 696 697 698 699 700 701 702 703
	}

	/* 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);
704
		goto out;
705 706 707 708 709
	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
710 711
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
712 713 714 715
	 */
	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);
716 717
		ret = false;
		goto out;
718 719 720 721 722 723
	}

	/* 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++;
724
	ieee80211_sta_reorder_release(hw, tid_agg_rx);
725

726 727 728
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
729 730 731 732 733 734
}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
735
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx)
736
{
737 738
	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
739 740
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
741
	struct sta_info *sta = rx->sta;
742 743 744 745 746
	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
	int tid;

	if (!ieee80211_is_data_qos(hdr->frame_control))
747
		goto dont_reorder;
748 749 750 751 752 753 754

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

	if (!sta)
755
		goto dont_reorder;
756 757 758

	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

759 760 761
	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
762 763 764

	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
765
		goto dont_reorder;
766 767 768 769 770 771 772 773 774 775 776

	/* 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) {
777
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
778 779
		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
780
		return;
781 782
	}

783 784 785 786 787 788 789
	/*
	 * 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.
	 */
790
	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb))
791 792 793
		return;

 dont_reorder:
794
	skb_queue_tail(&local->rx_skb_queue, skb);
795
}
796

797
static ieee80211_rx_result debug_noinline
798
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
799
{
800
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
801
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
802 803 804

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
805
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
806
			     rx->sta->last_seq_ctrl[rx->queue] ==
807
			     hdr->seq_ctrl)) {
808
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
809 810 811
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
812
			return RX_DROP_UNUSABLE;
813
		} else
814
			rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
815 816 817 818
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
Johannes Berg's avatar
Johannes Berg committed
819
		return RX_DROP_MONITOR;
820 821 822 823 824
	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
825 826
	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
827 828 829
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
830

Johannes Berg's avatar
Johannes Berg committed
831
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
832 833
		return ieee80211_rx_mesh_check(rx);

834 835
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
836
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
Bill Jordan's avatar
Bill Jordan committed
837
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
838
		     (!rx->sta || !test_sta_flags(rx->sta, WLAN_STA_ASSOC))))
Johannes Berg's avatar
Johannes Berg committed
839
		return RX_DROP_MONITOR;
840

841
	return RX_CONTINUE;
842 843 844
}


845
static ieee80211_rx_result debug_noinline
846
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
847
{
Johannes Berg's avatar
Johannes Berg committed
848 849 850
	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
851 852
	int keyidx;
	int hdrlen;
Johannes Berg's avatar
Johannes Berg committed
853
	ieee80211_rx_result result = RX_DROP_UNUSABLE;
854
	struct ieee80211_key *sta_ptk = NULL;
855
	int mmie_keyidx = -1;
856
	__le16 fc;
857

858 859 860
	/*
	 * Key selection 101
	 *
861
	 * There are four types of keys:
862
	 *  - GTK (group keys)
863
	 *  - IGTK (group keys for management frames)
864 865 866 867 868
	 *  - 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
869 870 871 872
	 * 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.
873
	 *
874 875 876 877
	 * 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.
	 *
878 879
	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
880 881 882
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
883 884 885
	 */

	/*
886
	 * No point in finding a key and decrypting if the frame is neither
887 888
	 * addressed to us nor a multicast frame.
	 */
889
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
890
		return RX_CONTINUE;
891

892 893 894
	/* start without a key */
	rx->key = NULL;

895
	if (rx->sta)
896
		sta_ptk = rcu_dereference(rx->sta->ptk);
897

898 899 900
	fc = hdr->frame_control;

	if (!ieee80211_has_protected(fc))
901 902
		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);

903 904
	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
		rx->key = sta_ptk;
905 906 907
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
			return RX_CONTINUE;
908
		/* Skip decryption if the frame is not protected. */
909
		if (!ieee80211_has_protected(fc))
910
			return RX_CONTINUE;
911 912
	} else if (mmie_keyidx >= 0) {
		/* Broadcast/multicast robust management frame / BIP */
Johannes Berg's avatar
Johannes Berg committed
913 914
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
915 916 917 918 919
			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 */
920 921 922 923
		if (rx->sta)
			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
		if (!rx->key)
			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
924
	} else if (!ieee80211_has_protected(fc)) {
925 926 927 928 929 930 931
		/*
		 * 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;
932 933 934
		struct ieee80211_sub_if_data *sdata = rx->sdata;
		int i;

935
		if (ieee80211_is_mgmt(fc) &&
936 937 938
		    is_multicast_ether_addr(hdr->addr1) &&
		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
			rx->key = key;
939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956
		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;
		}
957
		return RX_CONTINUE;
958
	} else {
959
		u8 keyid;
960 961 962 963 964 965 966 967 968
		/*
		 * 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
969 970
		if ((status->flag & RX_FLAG_DECRYPTED) &&
		    (status->flag & RX_FLAG_IV_STRIPPED))
971
			return RX_CONTINUE;
972

973
		hdrlen = ieee80211_hdrlen(fc);
974 975

		if (rx->skb->len < 8 + hdrlen)
Johannes Berg's avatar
Johannes Berg committed
976
			return RX_DROP_UNUSABLE; /* TODO: count this? */
977 978 979 980 981

		/*
		 * no need to call ieee80211_wep_get_keyidx,
		 * it verifies a bunch of things we've done already
		 */
982 983
		skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
		keyidx = keyid >> 6;
984

985 986 987
		/* 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]);
988

989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
		/* 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;
		}
1004 1005
	}

1006
	if (rx->key) {
1007
		rx->key->tx_rx_count++;
1008
		/* TODO: add threshold stuff again */
1009
	} else {
Johannes Berg's avatar
Johannes Berg committed
1010
		return RX_DROP_MONITOR;
1011 1012
	}

1013 1014
	if (skb_linearize(rx->skb))
		return RX_DROP_UNUSABLE;
1015
	/* the hdr variable is invalid now! */
1016

1017 1018 1019
	switch (rx->key->conf.cipher) {
	case WLAN_CIPHER_SUITE_WEP40:
	case WLAN_CIPHER_SUITE_WEP104:
1020 1021 1022 1023 1024 1025 1026
		/* 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, rx->key))
			rx->sta->wep_weak_iv_count++;

1027 1028
		result = ieee80211_crypto_wep_decrypt(rx);
		break;
1029
	case WLAN_CIPHER_SUITE_TKIP:
1030 1031
		result = ieee80211_crypto_tkip_decrypt(rx);
		break;
1032
	case WLAN_CIPHER_SUITE_CCMP:
1033 1034
		result = ieee80211_crypto_ccmp_decrypt(rx);
		break;
1035
	case WLAN_CIPHER_SUITE_AES_CMAC:
1036 1037
		result = ieee80211_crypto_aes_cmac_decrypt(rx);
		break;
1038 1039 1040 1041 1042 1043
	default:
		/*
		 * We can reach here only with HW-only algorithms
		 * but why didn't it decrypt the frame?!
		 */
		return RX_DROP_UNUSABLE;
1044 1045
	}

1046
	/* either the frame has been decrypted or will be dropped */
Johannes Berg's avatar
Johannes Berg committed
1047
	status->flag |= RX_FLAG_DECRYPTED;
1048 1049

	return result;
1050 1051
}

1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
{
	struct ieee80211_local *local;
	struct ieee80211_hdr *hdr;
	struct sk_buff *skb;

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

	if (!local->pspolling)
		return RX_CONTINUE;

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

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

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

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

	return RX_CONTINUE;
}

1085
static void ap_sta_ps_start(struct sta_info *sta)
1086
{
1087
	struct ieee80211_sub_if_data *sdata = sta->sdata;
1088
	struct ieee80211_local *local = sdata->local;
1089

1090
	atomic_inc(&sdata->bss->num_sta_ps);
1091
	set_sta_flags(sta, WLAN_STA_PS_STA);
1092 1093
	if (!(local->hw.flags & IEEE80211_HW_AP_LINK_PS))
		drv_sta_notify(local, sdata, STA_NOTIFY_SLEEP, &sta->sta);
1094
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
1095
	printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
1096
	       sdata->name, sta->sta.addr, sta->sta.aid);