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1 /*
2  * The gPXE 802.11 MAC layer.
3  *
4  * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of the
9  * License, or any later version.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19  */
20 
21 FILE_LICENCE ( GPL2_OR_LATER );
22 
23 #include <string.h>
24 #include <byteswap.h>
25 #include <stdlib.h>
26 #include <gpxe/settings.h>
27 #include <gpxe/if_arp.h>
28 #include <gpxe/ethernet.h>
29 #include <gpxe/ieee80211.h>
30 #include <gpxe/netdevice.h>
31 #include <gpxe/net80211.h>
32 #include <gpxe/sec80211.h>
33 #include <gpxe/timer.h>
34 #include <gpxe/nap.h>
35 #include <unistd.h>
36 #include <errno.h>
37 
38 /** @file
39  *
40  * 802.11 device management
41  */
42 
43 /* Disambiguate the EINVAL's a bit */
44 #define EINVAL_PKT_TOO_SHORT	( EINVAL | EUNIQ_01 )
45 #define EINVAL_PKT_VERSION	( EINVAL | EUNIQ_02 )
46 #define EINVAL_PKT_NOT_DATA	( EINVAL | EUNIQ_03 )
47 #define EINVAL_PKT_NOT_FROMDS	( EINVAL | EUNIQ_04 )
48 #define EINVAL_PKT_LLC_HEADER	( EINVAL | EUNIQ_05 )
49 #define EINVAL_CRYPTO_REQUEST	( EINVAL | EUNIQ_06 )
50 #define EINVAL_ACTIVE_SCAN	( EINVAL | EUNIQ_07 )
51 
52 /*
53  * 802.11 error codes: The AP can give us a status code explaining why
54  * authentication failed, or a reason code explaining why we were
55  * deauthenticated/disassociated. These codes range from 0-63 (the
56  * field is 16 bits wide, but only up to 45 or so are defined yet; we
57  * allow up to 63 for extensibility). This is encoded into an error
58  * code as such:
59  *
60  *                                      status & 0x1f goes here --vv--
61  *   Status code 0-31:  ECONNREFUSED | EUNIQ_(status & 0x1f) (0e1a6038)
62  *   Status code 32-63: EHOSTUNREACH | EUNIQ_(status & 0x1f) (171a6011)
63  *   Reason code 0-31:  ECONNRESET | EUNIQ_(reason & 0x1f)   (0f1a6039)
64  *   Reason code 32-63: ENETRESET | EUNIQ_(reason & 0x1f)    (271a6001)
65  *
66  * The POSIX error codes more or less convey the appropriate message
67  * (status codes occur when we can't associate at all, reason codes
68  * when we lose association unexpectedly) and let us extract the
69  * complete 802.11 error code from the rc value.
70  */
71 
72 /** Make return status code from 802.11 status code */
73 #define E80211_STATUS( stat )  ( ((stat & 0x20)? EHOSTUNREACH : ECONNREFUSED) \
74 					| ((stat & 0x1f) << 8) )
75 
76 /** Make return status code from 802.11 reason code */
77 #define E80211_REASON( reas )  ( ((reas & 0x20)? ENETRESET : ECONNRESET) \
78 					| ((reas & 0x1f) << 8) )
79 
80 
81 /** List of 802.11 devices */
82 static struct list_head net80211_devices = LIST_HEAD_INIT ( net80211_devices );
83 
84 /** Set of device operations that does nothing */
85 static struct net80211_device_operations net80211_null_ops;
86 
87 /** Information associated with a received management packet
88  *
89  * This is used to keep beacon signal strengths in a parallel queue to
90  * the beacons themselves.
91  */
92 struct net80211_rx_info {
93 	int signal;
94 	struct list_head list;
95 };
96 
97 /** Context for a probe operation */
98 struct net80211_probe_ctx {
99 	/** 802.11 device to probe on */
100 	struct net80211_device *dev;
101 
102 	/** Value of keep_mgmt before probe was started */
103 	int old_keep_mgmt;
104 
105 	/** If scanning actively, pointer to probe packet to send */
106 	struct io_buffer *probe;
107 
108 	/** If non-"", the ESSID to limit ourselves to */
109 	const char *essid;
110 
111 	/** Time probe was started */
112 	u32 ticks_start;
113 
114 	/** Time last useful beacon was received */
115 	u32 ticks_beacon;
116 
117 	/** Time channel was last changed */
118 	u32 ticks_channel;
119 
120 	/** Time to stay on each channel */
121 	u32 hop_time;
122 
123 	/** Channels to hop by when changing channel */
124 	int hop_step;
125 
126 	/** List of best beacons for each network found so far */
127 	struct list_head *beacons;
128 };
129 
130 /** Context for the association task */
131 struct net80211_assoc_ctx {
132 	/** Next authentication method to try using */
133 	int method;
134 
135 	/** Time (in ticks) of the last sent association-related packet */
136 	int last_packet;
137 
138 	/** Number of times we have tried sending it */
139 	int times_tried;
140 };
141 
142 /**
143  * @defgroup net80211_netdev Network device interface functions
144  * @{
145  */
146 static int net80211_netdev_open ( struct net_device *netdev );
147 static void net80211_netdev_close ( struct net_device *netdev );
148 static int net80211_netdev_transmit ( struct net_device *netdev,
149 				      struct io_buffer *iobuf );
150 static void net80211_netdev_poll ( struct net_device *netdev );
151 static void net80211_netdev_irq ( struct net_device *netdev, int enable );
152 /** @} */
153 
154 /**
155  * @defgroup net80211_linklayer 802.11 link-layer protocol functions
156  * @{
157  */
158 static int net80211_ll_push ( struct net_device *netdev,
159 			      struct io_buffer *iobuf, const void *ll_dest,
160 			      const void *ll_source, uint16_t net_proto );
161 static int net80211_ll_pull ( struct net_device *netdev,
162 			      struct io_buffer *iobuf, const void **ll_dest,
163 			      const void **ll_source, uint16_t * net_proto );
164 /** @} */
165 
166 /**
167  * @defgroup net80211_help 802.11 helper functions
168  * @{
169  */
170 static void net80211_add_channels ( struct net80211_device *dev, int start,
171 				    int len, int txpower );
172 static void net80211_filter_hw_channels ( struct net80211_device *dev );
173 static void net80211_set_rtscts_rate ( struct net80211_device *dev );
174 static int net80211_process_capab ( struct net80211_device *dev,
175 				    u16 capab );
176 static int net80211_process_ie ( struct net80211_device *dev,
177 				 union ieee80211_ie *ie, void *ie_end );
178 static union ieee80211_ie *
179 net80211_marshal_request_info ( struct net80211_device *dev,
180 				union ieee80211_ie *ie );
181 /** @} */
182 
183 /**
184  * @defgroup net80211_assoc_ll 802.11 association handling functions
185  * @{
186  */
187 static void net80211_step_associate ( struct process *proc );
188 static void net80211_handle_auth ( struct net80211_device *dev,
189 				   struct io_buffer *iob );
190 static void net80211_handle_assoc_reply ( struct net80211_device *dev,
191 					  struct io_buffer *iob );
192 static int net80211_send_disassoc ( struct net80211_device *dev, int reason,
193 				    int deauth );
194 static void net80211_handle_mgmt ( struct net80211_device *dev,
195 				   struct io_buffer *iob, int signal );
196 /** @} */
197 
198 /**
199  * @defgroup net80211_frag 802.11 fragment handling functions
200  * @{
201  */
202 static void net80211_free_frags ( struct net80211_device *dev, int fcid );
203 static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
204 						int fcid, int nfrags, int size );
205 static void net80211_rx_frag ( struct net80211_device *dev,
206 			       struct io_buffer *iob, int signal );
207 /** @} */
208 
209 /**
210  * @defgroup net80211_settings 802.11 settings handlers
211  * @{
212  */
213 static int net80211_check_settings_update ( void );
214 
215 /** 802.11 settings applicator
216  *
217  * When the SSID is changed, this will cause any open devices to
218  * re-associate; when the encryption key is changed, we similarly
219  * update their state.
220  */
221 struct settings_applicator net80211_applicator __settings_applicator = {
222 	.apply = net80211_check_settings_update,
223 };
224 
225 /** The network name to associate with
226  *
227  * If this is blank, we scan for all networks and use the one with the
228  * greatest signal strength.
229  */
230 struct setting net80211_ssid_setting __setting = {
231 	.name = "ssid",
232 	.description = "802.11 SSID (network name)",
233 	.type = &setting_type_string,
234 };
235 
236 /** Whether to use active scanning
237  *
238  * In order to associate with a hidden SSID, it's necessary to use an
239  * active scan (send probe packets). If this setting is nonzero, an
240  * active scan on the 2.4GHz band will be used to associate.
241  */
242 struct setting net80211_active_setting __setting = {
243 	.name = "active-scan",
244 	.description = "Use an active scan during 802.11 association",
245 	.type = &setting_type_int8,
246 };
247 
248 /** The cryptographic key to use
249  *
250  * For hex WEP keys, as is common, this must be entered using the
251  * normal gPXE method for entering hex settings; an ASCII string of
252  * hex characters will not behave as expected.
253  */
254 struct setting net80211_key_setting __setting = {
255 	.name = "key",
256 	.description = "Encryption key for protected 802.11 networks",
257 	.type = &setting_type_string,
258 };
259 
260 /** @} */
261 
262 
263 /* ---------- net_device wrapper ---------- */
264 
265 /**
266  * Open 802.11 device and start association
267  *
268  * @v netdev	Wrapping network device
269  * @ret rc	Return status code
270  *
271  * This sets up a default conservative set of channels for probing,
272  * and starts the auto-association task unless the @c
273  * NET80211_NO_ASSOC flag is set in the wrapped 802.11 device's @c
274  * state field.
275  */
net80211_netdev_open(struct net_device * netdev)276 static int net80211_netdev_open ( struct net_device *netdev )
277 {
278 	struct net80211_device *dev = netdev->priv;
279 	int rc = 0;
280 
281 	if ( dev->op == &net80211_null_ops )
282 		return -EFAULT;
283 
284 	if ( dev->op->open )
285 		rc = dev->op->open ( dev );
286 
287 	if ( rc < 0 )
288 		return rc;
289 
290 	if ( ! ( dev->state & NET80211_NO_ASSOC ) )
291 		net80211_autoassociate ( dev );
292 
293 	return 0;
294 }
295 
296 /**
297  * Close 802.11 device
298  *
299  * @v netdev	Wrapping network device.
300  *
301  * If the association task is running, this will stop it.
302  */
net80211_netdev_close(struct net_device * netdev)303 static void net80211_netdev_close ( struct net_device *netdev )
304 {
305 	struct net80211_device *dev = netdev->priv;
306 
307 	if ( dev->state & NET80211_WORKING )
308 		process_del ( &dev->proc_assoc );
309 
310 	/* Send disassociation frame to AP, to be polite */
311 	if ( dev->state & NET80211_ASSOCIATED )
312 		net80211_send_disassoc ( dev, IEEE80211_REASON_LEAVING, 0 );
313 
314 	if ( dev->handshaker && dev->handshaker->stop &&
315 	     dev->handshaker->started )
316 		dev->handshaker->stop ( dev );
317 
318 	free ( dev->crypto );
319 	free ( dev->handshaker );
320 	dev->crypto = NULL;
321 	dev->handshaker = NULL;
322 
323 	netdev_link_down ( netdev );
324 	dev->state = 0;
325 
326 	if ( dev->op->close )
327 		dev->op->close ( dev );
328 }
329 
330 /**
331  * Transmit packet on 802.11 device
332  *
333  * @v netdev	Wrapping network device
334  * @v iobuf	I/O buffer
335  * @ret rc	Return status code
336  *
337  * If encryption is enabled for the currently associated network, the
338  * packet will be encrypted prior to transmission.
339  */
net80211_netdev_transmit(struct net_device * netdev,struct io_buffer * iobuf)340 static int net80211_netdev_transmit ( struct net_device *netdev,
341 				      struct io_buffer *iobuf )
342 {
343 	struct net80211_device *dev = netdev->priv;
344 	struct ieee80211_frame *hdr = iobuf->data;
345 	int rc = -ENOSYS;
346 
347 	if ( dev->crypto && ! ( hdr->fc & IEEE80211_FC_PROTECTED ) &&
348 	     ( ( hdr->fc & IEEE80211_FC_TYPE ) == IEEE80211_TYPE_DATA ) ) {
349 		struct io_buffer *niob = dev->crypto->encrypt ( dev->crypto,
350 								iobuf );
351 		if ( ! niob )
352 			return -ENOMEM;	/* only reason encryption could fail */
353 
354 		/* Free the non-encrypted iob */
355 		netdev_tx_complete ( netdev, iobuf );
356 
357 		/* Transmit the encrypted iob; the Protected flag is
358 		   set, so we won't recurse into here again */
359 		netdev_tx ( netdev, niob );
360 
361 		/* Don't transmit the freed packet */
362 		return 0;
363 	}
364 
365 	if ( dev->op->transmit )
366 		rc = dev->op->transmit ( dev, iobuf );
367 
368 	return rc;
369 }
370 
371 /**
372  * Poll 802.11 device for received packets and completed transmissions
373  *
374  * @v netdev	Wrapping network device
375  */
net80211_netdev_poll(struct net_device * netdev)376 static void net80211_netdev_poll ( struct net_device *netdev )
377 {
378 	struct net80211_device *dev = netdev->priv;
379 
380 	if ( dev->op->poll )
381 		dev->op->poll ( dev );
382 }
383 
384 /**
385  * Enable or disable interrupts for 802.11 device
386  *
387  * @v netdev	Wrapping network device
388  * @v enable	Whether to enable interrupts
389  */
net80211_netdev_irq(struct net_device * netdev,int enable)390 static void net80211_netdev_irq ( struct net_device *netdev, int enable )
391 {
392 	struct net80211_device *dev = netdev->priv;
393 
394 	if ( dev->op->irq )
395 		dev->op->irq ( dev, enable );
396 }
397 
398 /** Network device operations for a wrapped 802.11 device */
399 static struct net_device_operations net80211_netdev_ops = {
400 	.open = net80211_netdev_open,
401 	.close = net80211_netdev_close,
402 	.transmit = net80211_netdev_transmit,
403 	.poll = net80211_netdev_poll,
404 	.irq = net80211_netdev_irq,
405 };
406 
407 
408 /* ---------- 802.11 link-layer protocol ---------- */
409 
410 /** 802.11 broadcast MAC address */
411 static u8 net80211_ll_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
412 
413 /**
414  * Determine whether a transmission rate uses ERP/OFDM
415  *
416  * @v rate	Rate in 100 kbps units
417  * @ret is_erp	TRUE if the rate is an ERP/OFDM rate
418  *
419  * 802.11b supports rates of 1.0, 2.0, 5.5, and 11.0 Mbps; any other
420  * rate than these on the 2.4GHz spectrum is an ERP (802.11g) rate.
421  */
net80211_rate_is_erp(u16 rate)422 static inline int net80211_rate_is_erp ( u16 rate )
423 {
424 	if ( rate == 10 || rate == 20 || rate == 55 || rate == 110 )
425 		return 0;
426 	return 1;
427 }
428 
429 
430 /**
431  * Calculate one frame's contribution to 802.11 duration field
432  *
433  * @v dev	802.11 device
434  * @v bytes	Amount of data to calculate duration for
435  * @ret dur	Duration field in microseconds
436  *
437  * To avoid multiple stations attempting to transmit at once, 802.11
438  * provides that every packet shall include a duration field
439  * specifying a length of time for which the wireless medium will be
440  * reserved after it is transmitted. The duration is measured in
441  * microseconds and is calculated with respect to the current
442  * physical-layer parameters of the 802.11 device.
443  *
444  * For an unfragmented data or management frame, or the last fragment
445  * of a fragmented frame, the duration captures only the 10 data bytes
446  * of one ACK; call once with bytes = 10.
447  *
448  * For a fragment of a data or management rame that will be followed
449  * by more fragments, the duration captures an ACK, the following
450  * fragment, and its ACK; add the results of three calls, two with
451  * bytes = 10 and one with bytes set to the next fragment's size.
452  *
453  * For an RTS control frame, the duration captures the responding CTS,
454  * the frame being sent, and its ACK; add the results of three calls,
455  * two with bytes = 10 and one with bytes set to the next frame's size
456  * (assuming unfragmented).
457  *
458  * For a CTS-to-self control frame, the duration captures the frame
459  * being protected and its ACK; add the results of two calls, one with
460  * bytes = 10 and one with bytes set to the next frame's size.
461  *
462  * No other frame types are currently supported by gPXE.
463  */
net80211_duration(struct net80211_device * dev,int bytes,u16 rate)464 u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate )
465 {
466 	struct net80211_channel *chan = &dev->channels[dev->channel];
467 	u32 kbps = rate * 100;
468 
469 	if ( chan->band == NET80211_BAND_5GHZ || net80211_rate_is_erp ( rate ) ) {
470 		/* OFDM encoding (802.11a/g) */
471 		int bits_per_symbol = ( kbps * 4 ) / 1000;	/* 4us/symbol */
472 		int bits = 22 + ( bytes << 3 );	/* 22-bit PLCP */
473 		int symbols = ( bits + bits_per_symbol - 1 ) / bits_per_symbol;
474 
475 		return 16 + 20 + ( symbols * 4 ); /* 16us SIFS, 20us preamble */
476 	} else {
477 		/* CCK encoding (802.11b) */
478 		int phy_time = 144 + 48;	/* preamble + PLCP */
479 		int bits = bytes << 3;
480 		int data_time = ( bits * 1000 + kbps - 1 ) / kbps;
481 
482 		if ( dev->phy_flags & NET80211_PHY_USE_SHORT_PREAMBLE )
483 			phy_time >>= 1;
484 
485 		return 10 + phy_time + data_time; /* 10us SIFS */
486 	}
487 }
488 
489 /**
490  * Add 802.11 link-layer header
491  *
492  * @v netdev		Wrapping network device
493  * @v iobuf		I/O buffer
494  * @v ll_dest		Link-layer destination address
495  * @v ll_source		Link-layer source address
496  * @v net_proto		Network-layer protocol, in network byte order
497  * @ret rc		Return status code
498  *
499  * This adds both the 802.11 frame header and the 802.2 LLC/SNAP
500  * header used on data packets.
501  *
502  * We also check here for state of the link that would make it invalid
503  * to send a data packet; every data packet must pass through here,
504  * and no non-data packet (e.g. management frame) should.
505  */
net80211_ll_push(struct net_device * netdev,struct io_buffer * iobuf,const void * ll_dest,const void * ll_source,uint16_t net_proto)506 static int net80211_ll_push ( struct net_device *netdev,
507 			      struct io_buffer *iobuf, const void *ll_dest,
508 			      const void *ll_source, uint16_t net_proto )
509 {
510 	struct net80211_device *dev = netdev->priv;
511 	struct ieee80211_frame *hdr = iob_push ( iobuf,
512 						 IEEE80211_LLC_HEADER_LEN +
513 						 IEEE80211_TYP_FRAME_HEADER_LEN );
514 	struct ieee80211_llc_snap_header *lhdr =
515 		( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
516 
517 	/* We can't send data packets if we're not associated. */
518 	if ( ! ( dev->state & NET80211_ASSOCIATED ) ) {
519 		if ( dev->assoc_rc )
520 			return dev->assoc_rc;
521 		return -ENETUNREACH;
522 	}
523 
524 	hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_DATA |
525 	    IEEE80211_STYPE_DATA | IEEE80211_FC_TODS;
526 
527 	/* We don't send fragmented frames, so duration is the time
528 	   for an SIFS + 10-byte ACK. */
529 	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
530 
531 	memcpy ( hdr->addr1, dev->bssid, ETH_ALEN );
532 	memcpy ( hdr->addr2, ll_source, ETH_ALEN );
533 	memcpy ( hdr->addr3, ll_dest, ETH_ALEN );
534 
535 	hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
536 
537 	lhdr->dsap = IEEE80211_LLC_DSAP;
538 	lhdr->ssap = IEEE80211_LLC_SSAP;
539 	lhdr->ctrl = IEEE80211_LLC_CTRL;
540 	memset ( lhdr->oui, 0x00, 3 );
541 	lhdr->ethertype = net_proto;
542 
543 	return 0;
544 }
545 
546 /**
547  * Remove 802.11 link-layer header
548  *
549  * @v netdev		Wrapping network device
550  * @v iobuf		I/O buffer
551  * @ret ll_dest		Link-layer destination address
552  * @ret ll_source	Link-layer source
553  * @ret net_proto	Network-layer protocol, in network byte order
554  * @ret rc		Return status code
555  *
556  * This expects and removes both the 802.11 frame header and the 802.2
557  * LLC/SNAP header that are used on data packets.
558  */
net80211_ll_pull(struct net_device * netdev __unused,struct io_buffer * iobuf,const void ** ll_dest,const void ** ll_source,uint16_t * net_proto)559 static int net80211_ll_pull ( struct net_device *netdev __unused,
560 			      struct io_buffer *iobuf,
561 			      const void **ll_dest, const void **ll_source,
562 			      uint16_t * net_proto )
563 {
564 	struct ieee80211_frame *hdr = iobuf->data;
565 	struct ieee80211_llc_snap_header *lhdr =
566 		( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
567 
568 	/* Bunch of sanity checks */
569 	if ( iob_len ( iobuf ) < IEEE80211_TYP_FRAME_HEADER_LEN +
570 	     IEEE80211_LLC_HEADER_LEN ) {
571 		DBGC ( netdev->priv, "802.11 %p packet too short (%zd bytes)\n",
572 		       netdev->priv, iob_len ( iobuf ) );
573 		return -EINVAL_PKT_TOO_SHORT;
574 	}
575 
576 	if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION ) {
577 		DBGC ( netdev->priv, "802.11 %p packet invalid version %04x\n",
578 		       netdev->priv, hdr->fc & IEEE80211_FC_VERSION );
579 		return -EINVAL_PKT_VERSION;
580 	}
581 
582 	if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_DATA ||
583 	     ( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA ) {
584 		DBGC ( netdev->priv, "802.11 %p packet not data/data (fc=%04x)\n",
585 		       netdev->priv, hdr->fc );
586 		return -EINVAL_PKT_NOT_DATA;
587 	}
588 
589 	if ( ( hdr->fc & ( IEEE80211_FC_TODS | IEEE80211_FC_FROMDS ) ) !=
590 	     IEEE80211_FC_FROMDS ) {
591 		DBGC ( netdev->priv, "802.11 %p packet not from DS (fc=%04x)\n",
592 		       netdev->priv, hdr->fc );
593 		return -EINVAL_PKT_NOT_FROMDS;
594 	}
595 
596 	if ( lhdr->dsap != IEEE80211_LLC_DSAP || lhdr->ssap != IEEE80211_LLC_SSAP ||
597 	     lhdr->ctrl != IEEE80211_LLC_CTRL || lhdr->oui[0] || lhdr->oui[1] ||
598 	     lhdr->oui[2] ) {
599 		DBGC ( netdev->priv, "802.11 %p LLC header is not plain EtherType "
600 		       "encapsulator: %02x->%02x [%02x] %02x:%02x:%02x %04x\n",
601 		       netdev->priv, lhdr->dsap, lhdr->ssap, lhdr->ctrl,
602 		       lhdr->oui[0], lhdr->oui[1], lhdr->oui[2], lhdr->ethertype );
603 		return -EINVAL_PKT_LLC_HEADER;
604 	}
605 
606 	iob_pull ( iobuf, sizeof ( *hdr ) + sizeof ( *lhdr ) );
607 
608 	*ll_dest = hdr->addr1;
609 	*ll_source = hdr->addr3;
610 	*net_proto = lhdr->ethertype;
611 	return 0;
612 }
613 
614 /** 802.11 link-layer protocol */
615 static struct ll_protocol net80211_ll_protocol __ll_protocol = {
616 	.name = "802.11",
617 	.push = net80211_ll_push,
618 	.pull = net80211_ll_pull,
619 	.init_addr = eth_init_addr,
620 	.ntoa = eth_ntoa,
621 	.mc_hash = eth_mc_hash,
622 	.eth_addr = eth_eth_addr,
623 	.ll_proto = htons ( ARPHRD_ETHER ),	/* "encapsulated Ethernet" */
624 	.hw_addr_len = ETH_ALEN,
625 	.ll_addr_len = ETH_ALEN,
626 	.ll_header_len = IEEE80211_TYP_FRAME_HEADER_LEN +
627 				IEEE80211_LLC_HEADER_LEN,
628 };
629 
630 
631 /* ---------- 802.11 network management API ---------- */
632 
633 /**
634  * Get 802.11 device from wrapping network device
635  *
636  * @v netdev	Wrapping network device
637  * @ret dev	802.11 device wrapped by network device, or NULL
638  *
639  * Returns NULL if the network device does not wrap an 802.11 device.
640  */
net80211_get(struct net_device * netdev)641 struct net80211_device * net80211_get ( struct net_device *netdev )
642 {
643 	struct net80211_device *dev;
644 
645 	list_for_each_entry ( dev, &net80211_devices, list ) {
646 		if ( netdev->priv == dev )
647 			return netdev->priv;
648 	}
649 
650 	return NULL;
651 }
652 
653 /**
654  * Set state of 802.11 device keeping management frames
655  *
656  * @v dev	802.11 device
657  * @v enable	Whether to keep management frames
658  * @ret oldenab	Whether management frames were enabled before this call
659  *
660  * If enable is TRUE, beacon, probe, and action frames will be kept
661  * and may be retrieved by calling net80211_mgmt_dequeue().
662  */
net80211_keep_mgmt(struct net80211_device * dev,int enable)663 int net80211_keep_mgmt ( struct net80211_device *dev, int enable )
664 {
665 	int oldenab = dev->keep_mgmt;
666 
667 	dev->keep_mgmt = enable;
668 	return oldenab;
669 }
670 
671 /**
672  * Get 802.11 management frame
673  *
674  * @v dev	802.11 device
675  * @ret signal	Signal strength of returned management frame
676  * @ret iob	I/O buffer, or NULL if no management frame is queued
677  *
678  * Frames will only be returned by this function if
679  * net80211_keep_mgmt() has been previously called with enable set to
680  * TRUE.
681  *
682  * The calling function takes ownership of the returned I/O buffer.
683  */
net80211_mgmt_dequeue(struct net80211_device * dev,int * signal)684 struct io_buffer * net80211_mgmt_dequeue ( struct net80211_device *dev,
685 					   int *signal )
686 {
687 	struct io_buffer *iobuf;
688 	struct net80211_rx_info *rxi;
689 
690 	list_for_each_entry ( rxi, &dev->mgmt_info_queue, list ) {
691 		list_del ( &rxi->list );
692 		if ( signal )
693 			*signal = rxi->signal;
694 		free ( rxi );
695 
696 		list_for_each_entry ( iobuf, &dev->mgmt_queue, list ) {
697 			list_del ( &iobuf->list );
698 			return iobuf;
699 		}
700 		assert ( 0 );
701 	}
702 
703 	return NULL;
704 }
705 
706 /**
707  * Transmit 802.11 management frame
708  *
709  * @v dev	802.11 device
710  * @v fc	Frame Control flags for management frame
711  * @v dest	Destination access point
712  * @v iob	I/O buffer
713  * @ret rc	Return status code
714  *
715  * The @a fc argument must contain at least an IEEE 802.11 management
716  * subtype number (e.g. IEEE80211_STYPE_PROBE_REQ). If it contains
717  * IEEE80211_FC_PROTECTED, the frame will be encrypted prior to
718  * transmission.
719  *
720  * It is required that @a iob have at least 24 bytes of headroom
721  * reserved before its data start.
722  */
net80211_tx_mgmt(struct net80211_device * dev,u16 fc,u8 dest[6],struct io_buffer * iob)723 int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc, u8 dest[6],
724 		       struct io_buffer *iob )
725 {
726 	struct ieee80211_frame *hdr = iob_push ( iob,
727 						 IEEE80211_TYP_FRAME_HEADER_LEN );
728 
729 	hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_MGMT |
730 	    ( fc & ~IEEE80211_FC_PROTECTED );
731 	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
732 	hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
733 
734 	memcpy ( hdr->addr1, dest, ETH_ALEN );	/* DA = RA */
735 	memcpy ( hdr->addr2, dev->netdev->ll_addr, ETH_ALEN );	/* SA = TA */
736 	memcpy ( hdr->addr3, dest, ETH_ALEN );	/* BSSID */
737 
738 	if ( fc & IEEE80211_FC_PROTECTED ) {
739 		if ( ! dev->crypto )
740 			return -EINVAL_CRYPTO_REQUEST;
741 
742 		struct io_buffer *eiob = dev->crypto->encrypt ( dev->crypto,
743 								iob );
744 		free_iob ( iob );
745 		iob = eiob;
746 	}
747 
748 	return netdev_tx ( dev->netdev, iob );
749 }
750 
751 
752 /* ---------- Driver API ---------- */
753 
754 /**
755  * Allocate 802.11 device
756  *
757  * @v priv_size		Size of driver-private allocation area
758  * @ret dev		Newly allocated 802.11 device
759  *
760  * This function allocates a net_device with space in its private area
761  * for both the net80211_device it will wrap and the driver-private
762  * data space requested. It initializes the link-layer-specific parts
763  * of the net_device, and links the net80211_device to the net_device
764  * appropriately.
765  */
net80211_alloc(size_t priv_size)766 struct net80211_device * net80211_alloc ( size_t priv_size )
767 {
768 	struct net80211_device *dev;
769 	struct net_device *netdev =
770 		alloc_netdev ( sizeof ( *dev ) + priv_size );
771 
772 	if ( ! netdev )
773 		return NULL;
774 
775 	netdev->ll_protocol = &net80211_ll_protocol;
776 	netdev->ll_broadcast = net80211_ll_broadcast;
777 	netdev->max_pkt_len = IEEE80211_MAX_DATA_LEN;
778 	netdev_init ( netdev, &net80211_netdev_ops );
779 
780 	dev = netdev->priv;
781 	dev->netdev = netdev;
782 	dev->priv = ( u8 * ) dev + sizeof ( *dev );
783 	dev->op = &net80211_null_ops;
784 
785 	process_init_stopped ( &dev->proc_assoc, net80211_step_associate,
786 			       &netdev->refcnt );
787 	INIT_LIST_HEAD ( &dev->mgmt_queue );
788 	INIT_LIST_HEAD ( &dev->mgmt_info_queue );
789 
790 	return dev;
791 }
792 
793 /**
794  * Register 802.11 device with network stack
795  *
796  * @v dev	802.11 device
797  * @v ops	802.11 device operations
798  * @v hw	802.11 hardware information
799  *
800  * This also registers the wrapping net_device with the higher network
801  * layers.
802  */
net80211_register(struct net80211_device * dev,struct net80211_device_operations * ops,struct net80211_hw_info * hw)803 int net80211_register ( struct net80211_device *dev,
804 			struct net80211_device_operations *ops,
805 			struct net80211_hw_info *hw )
806 {
807 	dev->op = ops;
808 	dev->hw = malloc ( sizeof ( *hw ) );
809 	if ( ! dev->hw )
810 		return -ENOMEM;
811 
812 	memcpy ( dev->hw, hw, sizeof ( *hw ) );
813 	memcpy ( dev->netdev->hw_addr, hw->hwaddr, ETH_ALEN );
814 
815 	/* Set some sensible channel defaults for driver's open() function */
816 	memcpy ( dev->channels, dev->hw->channels,
817 		 NET80211_MAX_CHANNELS * sizeof ( dev->channels[0] ) );
818 	dev->channel = 0;
819 
820 	list_add_tail ( &dev->list, &net80211_devices );
821 	return register_netdev ( dev->netdev );
822 }
823 
824 /**
825  * Unregister 802.11 device from network stack
826  *
827  * @v dev	802.11 device
828  *
829  * After this call, the device operations are cleared so that they
830  * will not be called.
831  */
net80211_unregister(struct net80211_device * dev)832 void net80211_unregister ( struct net80211_device *dev )
833 {
834 	unregister_netdev ( dev->netdev );
835 	list_del ( &dev->list );
836 	dev->op = &net80211_null_ops;
837 }
838 
839 /**
840  * Free 802.11 device
841  *
842  * @v dev	802.11 device
843  *
844  * The device should be unregistered before this function is called.
845  */
net80211_free(struct net80211_device * dev)846 void net80211_free ( struct net80211_device *dev )
847 {
848 	free ( dev->hw );
849 	rc80211_free ( dev->rctl );
850 	netdev_nullify ( dev->netdev );
851 	netdev_put ( dev->netdev );
852 }
853 
854 
855 /* ---------- 802.11 network management workhorse code ---------- */
856 
857 /**
858  * Set state of 802.11 device
859  *
860  * @v dev	802.11 device
861  * @v clear	Bitmask of flags to clear
862  * @v set	Bitmask of flags to set
863  * @v status	Status or reason code for most recent operation
864  *
865  * If @a status represents a reason code, it should be OR'ed with
866  * NET80211_IS_REASON.
867  *
868  * Clearing authentication also clears association; clearing
869  * association also clears security handshaking state. Clearing
870  * association removes the link-up flag from the wrapping net_device,
871  * but setting it does not automatically set the flag; that is left to
872  * the judgment of higher-level code.
873  */
net80211_set_state(struct net80211_device * dev,short clear,short set,u16 status)874 static inline void net80211_set_state ( struct net80211_device *dev,
875 					short clear, short set,
876 					u16 status )
877 {
878 	/* The conditions in this function are deliberately formulated
879 	   to be decidable at compile-time in most cases. Since clear
880 	   and set are generally passed as constants, the body of this
881 	   function can be reduced down to a few statements by the
882 	   compiler. */
883 
884 	const int statmsk = NET80211_STATUS_MASK | NET80211_IS_REASON;
885 
886 	if ( clear & NET80211_PROBED )
887 		clear |= NET80211_AUTHENTICATED;
888 
889 	if ( clear & NET80211_AUTHENTICATED )
890 		clear |= NET80211_ASSOCIATED;
891 
892 	if ( clear & NET80211_ASSOCIATED )
893 		clear |= NET80211_CRYPTO_SYNCED;
894 
895 	dev->state = ( dev->state & ~clear ) | set;
896 	dev->state = ( dev->state & ~statmsk ) | ( status & statmsk );
897 
898 	if ( clear & NET80211_ASSOCIATED )
899 		netdev_link_down ( dev->netdev );
900 
901 	if ( ( clear | set ) & NET80211_ASSOCIATED )
902 		dev->op->config ( dev, NET80211_CFG_ASSOC );
903 
904 	if ( status != 0 ) {
905 		if ( status & NET80211_IS_REASON )
906 			dev->assoc_rc = -E80211_REASON ( status );
907 		else
908 			dev->assoc_rc = -E80211_STATUS ( status );
909 		netdev_link_err ( dev->netdev, dev->assoc_rc );
910 	}
911 }
912 
913 /**
914  * Add channels to 802.11 device
915  *
916  * @v dev	802.11 device
917  * @v start	First channel number to add
918  * @v len	Number of channels to add
919  * @v txpower	TX power (dBm) to allow on added channels
920  *
921  * To replace the current list of channels instead of adding to it,
922  * set the nr_channels field of the 802.11 device to 0 before calling
923  * this function.
924  */
net80211_add_channels(struct net80211_device * dev,int start,int len,int txpower)925 static void net80211_add_channels ( struct net80211_device *dev, int start,
926 				    int len, int txpower )
927 {
928 	int i, chan = start;
929 
930 	for ( i = dev->nr_channels; len-- && i < NET80211_MAX_CHANNELS; i++ ) {
931 		dev->channels[i].channel_nr = chan;
932 		dev->channels[i].maxpower = txpower;
933 		dev->channels[i].hw_value = 0;
934 
935 		if ( chan >= 1 && chan <= 14 ) {
936 			dev->channels[i].band = NET80211_BAND_2GHZ;
937 			if ( chan == 14 )
938 				dev->channels[i].center_freq = 2484;
939 			else
940 				dev->channels[i].center_freq = 2407 + 5 * chan;
941 			chan++;
942 		} else {
943 			dev->channels[i].band = NET80211_BAND_5GHZ;
944 			dev->channels[i].center_freq = 5000 + 5 * chan;
945 			chan += 4;
946 		}
947 	}
948 
949 	dev->nr_channels = i;
950 }
951 
952 /**
953  * Filter 802.11 device channels for hardware capabilities
954  *
955  * @v dev	802.11 device
956  *
957  * Hardware may support fewer channels than regulatory restrictions
958  * allow; this function filters out channels in dev->channels that are
959  * not supported by the hardware list in dev->hwinfo. It also copies
960  * over the net80211_channel::hw_value and limits maximum TX power
961  * appropriately.
962  *
963  * Channels are matched based on center frequency, ignoring band and
964  * channel number.
965  *
966  * If the driver specifies no supported channels, the effect will be
967  * as though all were supported.
968  */
net80211_filter_hw_channels(struct net80211_device * dev)969 static void net80211_filter_hw_channels ( struct net80211_device *dev )
970 {
971 	int delta = 0, i = 0;
972 	int old_freq = dev->channels[dev->channel].center_freq;
973 	struct net80211_channel *chan, *hwchan;
974 
975 	if ( ! dev->hw->nr_channels )
976 		return;
977 
978 	dev->channel = 0;
979 	for ( chan = dev->channels; chan < dev->channels + dev->nr_channels;
980 	      chan++, i++ ) {
981 		int ok = 0;
982 		for ( hwchan = dev->hw->channels;
983 		      hwchan < dev->hw->channels + dev->hw->nr_channels;
984 		      hwchan++ ) {
985 			if ( hwchan->center_freq == chan->center_freq ) {
986 				ok = 1;
987 				break;
988 			}
989 		}
990 
991 		if ( ! ok )
992 			delta++;
993 		else {
994 			chan->hw_value = hwchan->hw_value;
995 			if ( hwchan->maxpower != 0 &&
996 			     chan->maxpower > hwchan->maxpower )
997 				chan->maxpower = hwchan->maxpower;
998 			if ( old_freq == chan->center_freq )
999 				dev->channel = i - delta;
1000 			if ( delta )
1001 				chan[-delta] = *chan;
1002 		}
1003 	}
1004 
1005 	dev->nr_channels -= delta;
1006 
1007 	if ( dev->channels[dev->channel].center_freq != old_freq )
1008 		dev->op->config ( dev, NET80211_CFG_CHANNEL );
1009 }
1010 
1011 /**
1012  * Update 802.11 device state to reflect received capabilities field
1013  *
1014  * @v dev	802.11 device
1015  * @v capab	Capabilities field in beacon, probe, or association frame
1016  * @ret rc	Return status code
1017  */
net80211_process_capab(struct net80211_device * dev,u16 capab)1018 static int net80211_process_capab ( struct net80211_device *dev,
1019 				    u16 capab )
1020 {
1021 	u16 old_phy = dev->phy_flags;
1022 
1023 	if ( ( capab & ( IEEE80211_CAPAB_MANAGED | IEEE80211_CAPAB_ADHOC ) ) !=
1024 	     IEEE80211_CAPAB_MANAGED ) {
1025 		DBGC ( dev, "802.11 %p cannot handle IBSS network\n", dev );
1026 		return -ENOSYS;
1027 	}
1028 
1029 	dev->phy_flags &= ~( NET80211_PHY_USE_SHORT_PREAMBLE |
1030 			     NET80211_PHY_USE_SHORT_SLOT );
1031 
1032 	if ( capab & IEEE80211_CAPAB_SHORT_PMBL )
1033 		dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
1034 
1035 	if ( capab & IEEE80211_CAPAB_SHORT_SLOT )
1036 		dev->phy_flags |= NET80211_PHY_USE_SHORT_SLOT;
1037 
1038 	if ( old_phy != dev->phy_flags )
1039 		dev->op->config ( dev, NET80211_CFG_PHY_PARAMS );
1040 
1041 	return 0;
1042 }
1043 
1044 /**
1045  * Update 802.11 device state to reflect received information elements
1046  *
1047  * @v dev	802.11 device
1048  * @v ie	Pointer to first information element
1049  * @v ie_end	Pointer to tail of packet I/O buffer
1050  * @ret rc	Return status code
1051  */
net80211_process_ie(struct net80211_device * dev,union ieee80211_ie * ie,void * ie_end)1052 static int net80211_process_ie ( struct net80211_device *dev,
1053 				 union ieee80211_ie *ie, void *ie_end )
1054 {
1055 	u16 old_rate = dev->rates[dev->rate];
1056 	u16 old_phy = dev->phy_flags;
1057 	int have_rates = 0, i;
1058 	int ds_channel = 0;
1059 	int changed = 0;
1060 	int band = dev->channels[dev->channel].band;
1061 
1062 	if ( ! ieee80211_ie_bound ( ie, ie_end ) )
1063 		return 0;
1064 
1065 	for ( ; ie; ie = ieee80211_next_ie ( ie, ie_end ) ) {
1066 		switch ( ie->id ) {
1067 		case IEEE80211_IE_SSID:
1068 			if ( ie->len <= 32 ) {
1069 				memcpy ( dev->essid, ie->ssid, ie->len );
1070 				dev->essid[ie->len] = 0;
1071 			}
1072 			break;
1073 
1074 		case IEEE80211_IE_RATES:
1075 		case IEEE80211_IE_EXT_RATES:
1076 			if ( ! have_rates ) {
1077 				dev->nr_rates = 0;
1078 				dev->basic_rates = 0;
1079 				have_rates = 1;
1080 			}
1081 			for ( i = 0; i < ie->len &&
1082 			      dev->nr_rates < NET80211_MAX_RATES; i++ ) {
1083 				u8 rid = ie->rates[i];
1084 				u16 rate = ( rid & 0x7f ) * 5;
1085 
1086 				if ( rid & 0x80 )
1087 					dev->basic_rates |=
1088 						( 1 << dev->nr_rates );
1089 
1090 				dev->rates[dev->nr_rates++] = rate;
1091 			}
1092 
1093 			break;
1094 
1095 		case IEEE80211_IE_DS_PARAM:
1096 			if ( dev->channel < dev->nr_channels && ds_channel ==
1097 			     dev->channels[dev->channel].channel_nr )
1098 				break;
1099 			ds_channel = ie->ds_param.current_channel;
1100 			net80211_change_channel ( dev, ds_channel );
1101 			break;
1102 
1103 		case IEEE80211_IE_COUNTRY:
1104 			dev->nr_channels = 0;
1105 
1106 			DBGC ( dev, "802.11 %p setting country regulations "
1107 			       "for %c%c\n", dev, ie->country.name[0],
1108 			       ie->country.name[1] );
1109 			for ( i = 0; i < ( ie->len - 3 ) / 3; i++ ) {
1110 				union ieee80211_ie_country_triplet *t =
1111 					&ie->country.triplet[i];
1112 				if ( t->first > 200 ) {
1113 					DBGC ( dev, "802.11 %p ignoring regulatory "
1114 					       "extension information\n", dev );
1115 				} else {
1116 					net80211_add_channels ( dev,
1117 							t->band.first_channel,
1118 							t->band.nr_channels,
1119 							t->band.max_txpower );
1120 				}
1121 			}
1122 			net80211_filter_hw_channels ( dev );
1123 			break;
1124 
1125 		case IEEE80211_IE_ERP_INFO:
1126 			dev->phy_flags &= ~( NET80211_PHY_USE_PROTECTION |
1127 					     NET80211_PHY_USE_SHORT_PREAMBLE );
1128 			if ( ie->erp_info & IEEE80211_ERP_USE_PROTECTION )
1129 				dev->phy_flags |= NET80211_PHY_USE_PROTECTION;
1130 			if ( ! ( ie->erp_info & IEEE80211_ERP_BARKER_LONG ) )
1131 				dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
1132 			break;
1133 		}
1134 	}
1135 
1136 	if ( have_rates ) {
1137 		/* Allow only those rates that are also supported by
1138 		   the hardware. */
1139 		int delta = 0, j;
1140 
1141 		dev->rate = 0;
1142 		for ( i = 0; i < dev->nr_rates; i++ ) {
1143 			int ok = 0;
1144 			for ( j = 0; j < dev->hw->nr_rates[band]; j++ ) {
1145 				if ( dev->hw->rates[band][j] == dev->rates[i] ){
1146 					ok = 1;
1147 					break;
1148 				}
1149 			}
1150 
1151 			if ( ! ok )
1152 				delta++;
1153 			else {
1154 				dev->rates[i - delta] = dev->rates[i];
1155 				if ( old_rate == dev->rates[i] )
1156 					dev->rate = i - delta;
1157 			}
1158 		}
1159 
1160 		dev->nr_rates -= delta;
1161 
1162 		/* Sort available rates - sorted subclumps tend to already
1163 		   exist, so insertion sort works well. */
1164 		for ( i = 1; i < dev->nr_rates; i++ ) {
1165 			u16 rate = dev->rates[i];
1166 			u32 tmp, br, mask;
1167 
1168 			for ( j = i - 1; j >= 0 && dev->rates[j] >= rate; j-- )
1169 				dev->rates[j + 1] = dev->rates[j];
1170 			dev->rates[j + 1] = rate;
1171 
1172 			/* Adjust basic_rates to match by rotating the
1173 			   bits from bit j+1 to bit i left one position. */
1174 			mask = ( ( 1 << i ) - 1 ) & ~( ( 1 << ( j + 1 ) ) - 1 );
1175 			br = dev->basic_rates;
1176 			tmp = br & ( 1 << i );
1177 			br = ( br & ~( mask | tmp ) ) | ( ( br & mask ) << 1 );
1178 			br |= ( tmp >> ( i - j - 1 ) );
1179 			dev->basic_rates = br;
1180 		}
1181 
1182 		net80211_set_rtscts_rate ( dev );
1183 
1184 		if ( dev->rates[dev->rate] != old_rate )
1185 			changed |= NET80211_CFG_RATE;
1186 	}
1187 
1188 	if ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE )
1189 		dev->phy_flags &= ~NET80211_PHY_USE_SHORT_PREAMBLE;
1190 	if ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT )
1191 		dev->phy_flags &= ~NET80211_PHY_USE_SHORT_SLOT;
1192 
1193 	if ( old_phy != dev->phy_flags )
1194 		changed |= NET80211_CFG_PHY_PARAMS;
1195 
1196 	if ( changed )
1197 		dev->op->config ( dev, changed );
1198 
1199 	return 0;
1200 }
1201 
1202 /**
1203  * Create information elements for outgoing probe or association packet
1204  *
1205  * @v dev		802.11 device
1206  * @v ie		Pointer to start of information element area
1207  * @ret next_ie		Pointer to first byte after added information elements
1208  */
1209 static union ieee80211_ie *
net80211_marshal_request_info(struct net80211_device * dev,union ieee80211_ie * ie)1210 net80211_marshal_request_info ( struct net80211_device *dev,
1211 				union ieee80211_ie *ie )
1212 {
1213 	int i;
1214 
1215 	ie->id = IEEE80211_IE_SSID;
1216 	ie->len = strlen ( dev->essid );
1217 	memcpy ( ie->ssid, dev->essid, ie->len );
1218 
1219 	ie = ieee80211_next_ie ( ie, NULL );
1220 
1221 	ie->id = IEEE80211_IE_RATES;
1222 	ie->len = dev->nr_rates;
1223 	if ( ie->len > 8 )
1224 		ie->len = 8;
1225 
1226 	for ( i = 0; i < ie->len; i++ ) {
1227 		ie->rates[i] = dev->rates[i] / 5;
1228 		if ( dev->basic_rates & ( 1 << i ) )
1229 			ie->rates[i] |= 0x80;
1230 	}
1231 
1232 	ie = ieee80211_next_ie ( ie, NULL );
1233 
1234 	if ( dev->rsn_ie && dev->rsn_ie->id == IEEE80211_IE_RSN ) {
1235 		memcpy ( ie, dev->rsn_ie, dev->rsn_ie->len + 2 );
1236 		ie = ieee80211_next_ie ( ie, NULL );
1237 	}
1238 
1239 	if ( dev->nr_rates > 8 ) {
1240 		/* 802.11 requires we use an Extended Basic Rates IE
1241 		   for the rates beyond the eighth. */
1242 
1243 		ie->id = IEEE80211_IE_EXT_RATES;
1244 		ie->len = dev->nr_rates - 8;
1245 
1246 		for ( ; i < dev->nr_rates; i++ ) {
1247 			ie->rates[i - 8] = dev->rates[i] / 5;
1248 			if ( dev->basic_rates & ( 1 << i ) )
1249 				ie->rates[i - 8] |= 0x80;
1250 		}
1251 
1252 		ie = ieee80211_next_ie ( ie, NULL );
1253 	}
1254 
1255 	if ( dev->rsn_ie && dev->rsn_ie->id == IEEE80211_IE_VENDOR ) {
1256 		memcpy ( ie, dev->rsn_ie, dev->rsn_ie->len + 2 );
1257 		ie = ieee80211_next_ie ( ie, NULL );
1258 	}
1259 
1260 	return ie;
1261 }
1262 
1263 /** Seconds to wait after finding a network, to possibly find better APs for it
1264  *
1265  * This is used when a specific SSID to scan for is specified.
1266  */
1267 #define NET80211_PROBE_GATHER    1
1268 
1269 /** Seconds to wait after finding a network, to possibly find other networks
1270  *
1271  * This is used when an empty SSID is specified, to scan for all
1272  * networks.
1273  */
1274 #define NET80211_PROBE_GATHER_ALL 2
1275 
1276 /** Seconds to allow a probe to take if no network has been found */
1277 #define NET80211_PROBE_TIMEOUT   6
1278 
1279 /**
1280  * Begin probe of 802.11 networks
1281  *
1282  * @v dev	802.11 device
1283  * @v essid	SSID to probe for, or "" to accept any (may not be NULL)
1284  * @v active	Whether to use active scanning
1285  * @ret ctx	Probe context
1286  *
1287  * Active scanning may only be used on channels 1-11 in the 2.4GHz
1288  * band, due to gPXE's lack of a complete regulatory database. If
1289  * active scanning is used, probe packets will be sent on each
1290  * channel; this can allow association with hidden-SSID networks if
1291  * the SSID is properly specified.
1292  *
1293  * A @c NULL return indicates an out-of-memory condition.
1294  *
1295  * The returned context must be periodically passed to
1296  * net80211_probe_step() until that function returns zero.
1297  */
net80211_probe_start(struct net80211_device * dev,const char * essid,int active)1298 struct net80211_probe_ctx * net80211_probe_start ( struct net80211_device *dev,
1299 						   const char *essid,
1300 						   int active )
1301 {
1302 	struct net80211_probe_ctx *ctx = zalloc ( sizeof ( *ctx ) );
1303 
1304 	if ( ! ctx )
1305 		return NULL;
1306 
1307 	assert ( dev->netdev->state & NETDEV_OPEN );
1308 
1309 	ctx->dev = dev;
1310 	ctx->old_keep_mgmt = net80211_keep_mgmt ( dev, 1 );
1311 	ctx->essid = essid;
1312 	if ( dev->essid != ctx->essid )
1313 		strcpy ( dev->essid, ctx->essid );
1314 
1315 	if ( active ) {
1316 		struct ieee80211_probe_req *probe_req;
1317 		union ieee80211_ie *ie;
1318 
1319 		ctx->probe = alloc_iob ( 128 );
1320 		iob_reserve ( ctx->probe, IEEE80211_TYP_FRAME_HEADER_LEN );
1321 		probe_req = ctx->probe->data;
1322 
1323 		ie = net80211_marshal_request_info ( dev,
1324 						     probe_req->info_element );
1325 
1326 		iob_put ( ctx->probe, ( void * ) ie - ctx->probe->data );
1327 	}
1328 
1329 	ctx->ticks_start = currticks();
1330 	ctx->ticks_beacon = 0;
1331 	ctx->ticks_channel = currticks();
1332 	ctx->hop_time = ticks_per_sec() / ( active ? 2 : 6 );
1333 
1334 	/*
1335 	 * Channels on 2.4GHz overlap, and the most commonly used
1336 	 * are 1, 6, and 11. We'll get a result faster if we check
1337 	 * every 5 channels, but in order to hit all of them the
1338 	 * number of channels must be relatively prime to 5. If it's
1339 	 * not, tweak the hop.
1340 	 */
1341 	ctx->hop_step = 5;
1342 	while ( dev->nr_channels % ctx->hop_step == 0 && ctx->hop_step > 1 )
1343 		ctx->hop_step--;
1344 
1345 	ctx->beacons = malloc ( sizeof ( *ctx->beacons ) );
1346 	INIT_LIST_HEAD ( ctx->beacons );
1347 
1348 	dev->channel = 0;
1349 	dev->op->config ( dev, NET80211_CFG_CHANNEL );
1350 
1351 	return ctx;
1352 }
1353 
1354 /**
1355  * Continue probe of 802.11 networks
1356  *
1357  * @v ctx	Probe context returned by net80211_probe_start()
1358  * @ret rc	Probe status
1359  *
1360  * The return code will be 0 if the probe is still going on (and this
1361  * function should be called again), a positive number if the probe
1362  * completed successfully, or a negative error code if the probe
1363  * failed for that reason.
1364  *
1365  * Whether the probe succeeded or failed, you must call
1366  * net80211_probe_finish_all() or net80211_probe_finish_best()
1367  * (depending on whether you want information on all networks or just
1368  * the best-signal one) in order to release the probe context. A
1369  * failed probe may still have acquired some valid data.
1370  */
net80211_probe_step(struct net80211_probe_ctx * ctx)1371 int net80211_probe_step ( struct net80211_probe_ctx *ctx )
1372 {
1373 	struct net80211_device *dev = ctx->dev;
1374 	u32 start_timeout = NET80211_PROBE_TIMEOUT * ticks_per_sec();
1375 	u32 gather_timeout = ticks_per_sec();
1376 	u32 now = currticks();
1377 	struct io_buffer *iob;
1378 	int signal;
1379 	int rc;
1380 	char ssid[IEEE80211_MAX_SSID_LEN + 1];
1381 
1382 	gather_timeout *= ( ctx->essid[0] ? NET80211_PROBE_GATHER :
1383 			    NET80211_PROBE_GATHER_ALL );
1384 
1385 	/* Time out if necessary */
1386 	if ( now >= ctx->ticks_start + start_timeout )
1387 		return list_empty ( ctx->beacons ) ? -ETIMEDOUT : +1;
1388 
1389 	if ( ctx->ticks_beacon > 0 && now >= ctx->ticks_start + gather_timeout )
1390 		return +1;
1391 
1392 	/* Change channels if necessary */
1393 	if ( now >= ctx->ticks_channel + ctx->hop_time ) {
1394 		dev->channel = ( dev->channel + ctx->hop_step )
1395 			% dev->nr_channels;
1396 		dev->op->config ( dev, NET80211_CFG_CHANNEL );
1397 		udelay ( dev->hw->channel_change_time );
1398 
1399 		ctx->ticks_channel = now;
1400 
1401 		if ( ctx->probe ) {
1402 			struct io_buffer *siob = ctx->probe; /* to send */
1403 
1404 			/* make a copy for future use */
1405 			iob = alloc_iob ( siob->tail - siob->head );
1406 			iob_reserve ( iob, iob_headroom ( siob ) );
1407 			memcpy ( iob_put ( iob, iob_len ( siob ) ),
1408 				 siob->data, iob_len ( siob ) );
1409 
1410 			ctx->probe = iob;
1411 			rc = net80211_tx_mgmt ( dev, IEEE80211_STYPE_PROBE_REQ,
1412 						net80211_ll_broadcast,
1413 						iob_disown ( siob ) );
1414 			if ( rc ) {
1415 				DBGC ( dev, "802.11 %p send probe failed: "
1416 				       "%s\n", dev, strerror ( rc ) );
1417 				return rc;
1418 			}
1419 		}
1420 	}
1421 
1422 	/* Check for new management packets */
1423 	while ( ( iob = net80211_mgmt_dequeue ( dev, &signal ) ) != NULL ) {
1424 		struct ieee80211_frame *hdr;
1425 		struct ieee80211_beacon *beacon;
1426 		union ieee80211_ie *ie;
1427 		struct net80211_wlan *wlan;
1428 		u16 type;
1429 
1430 		hdr = iob->data;
1431 		type = hdr->fc & IEEE80211_FC_SUBTYPE;
1432 		beacon = ( struct ieee80211_beacon * ) hdr->data;
1433 
1434 		if ( type != IEEE80211_STYPE_BEACON &&
1435 		     type != IEEE80211_STYPE_PROBE_RESP ) {
1436 			DBGC2 ( dev, "802.11 %p probe: non-beacon\n", dev );
1437 			goto drop;
1438 		}
1439 
1440 		if ( ( void * ) beacon->info_element >= iob->tail ) {
1441 			DBGC ( dev, "802.11 %p probe: beacon with no IEs\n",
1442 			       dev );
1443 			goto drop;
1444 		}
1445 
1446 		ie = beacon->info_element;
1447 
1448 		if ( ! ieee80211_ie_bound ( ie, iob->tail ) )
1449 			ie = NULL;
1450 
1451 		while ( ie && ie->id != IEEE80211_IE_SSID )
1452 			ie = ieee80211_next_ie ( ie, iob->tail );
1453 
1454 		if ( ! ie ) {
1455 			DBGC ( dev, "802.11 %p probe: beacon with no SSID\n",
1456 			       dev );
1457 			goto drop;
1458 		}
1459 
1460 		memcpy ( ssid, ie->ssid, ie->len );
1461 		ssid[ie->len] = 0;
1462 
1463 		if ( ctx->essid[0] && strcmp ( ctx->essid, ssid ) != 0 ) {
1464 			DBGC2 ( dev, "802.11 %p probe: beacon with wrong SSID "
1465 				"(%s)\n", dev, ssid );
1466 			goto drop;
1467 		}
1468 
1469 		/* See if we've got an entry for this network */
1470 		list_for_each_entry ( wlan, ctx->beacons, list ) {
1471 			if ( strcmp ( wlan->essid, ssid ) != 0 )
1472 				continue;
1473 
1474 			if ( signal < wlan->signal ) {
1475 				DBGC2 ( dev, "802.11 %p probe: beacon for %s "
1476 					"(%s) with weaker signal %d\n", dev,
1477 					ssid, eth_ntoa ( hdr->addr3 ), signal );
1478 				goto drop;
1479 			}
1480 
1481 			goto fill;
1482 		}
1483 
1484 		/* No entry yet - make one */
1485 		wlan = zalloc ( sizeof ( *wlan ) );
1486 		strcpy ( wlan->essid, ssid );
1487 		list_add_tail ( &wlan->list, ctx->beacons );
1488 
1489 		/* Whether we're using an old entry or a new one, fill
1490 		   it with new data. */
1491 	fill:
1492 		memcpy ( wlan->bssid, hdr->addr3, ETH_ALEN );
1493 		wlan->signal = signal;
1494 		wlan->channel = dev->channels[dev->channel].channel_nr;
1495 
1496 		/* Copy this I/O buffer into a new wlan->beacon; the
1497 		 * iob we've got probably came from the device driver
1498 		 * and may have the full 2.4k allocation, which we
1499 		 * don't want to keep around wasting memory.
1500 		 */
1501 		free_iob ( wlan->beacon );
1502 		wlan->beacon = alloc_iob ( iob_len ( iob ) );
1503 		memcpy ( iob_put ( wlan->beacon, iob_len ( iob ) ),
1504 			 iob->data, iob_len ( iob ) );
1505 
1506 		if ( ( rc = sec80211_detect ( wlan->beacon, &wlan->handshaking,
1507 					      &wlan->crypto ) ) == -ENOTSUP ) {
1508 			struct ieee80211_beacon *beacon =
1509 				( struct ieee80211_beacon * ) hdr->data;
1510 
1511 			if ( beacon->capability & IEEE80211_CAPAB_PRIVACY ) {
1512 				DBG ( "802.11 %p probe: secured network %s but "
1513 				      "encryption support not compiled in\n",
1514 				      dev, wlan->essid );
1515 				wlan->handshaking = NET80211_SECPROT_UNKNOWN;
1516 				wlan->crypto = NET80211_CRYPT_UNKNOWN;
1517 			} else {
1518 				wlan->handshaking = NET80211_SECPROT_NONE;
1519 				wlan->crypto = NET80211_CRYPT_NONE;
1520 			}
1521 		} else if ( rc != 0 ) {
1522 			DBGC ( dev, "802.11 %p probe warning: network "
1523 			       "%s with unidentifiable security "
1524 			       "settings: %s\n", dev, wlan->essid,
1525 			       strerror ( rc ) );
1526 		}
1527 
1528 		ctx->ticks_beacon = now;
1529 
1530 		DBGC2 ( dev, "802.11 %p probe: good beacon for %s (%s)\n",
1531 			dev, wlan->essid, eth_ntoa ( wlan->bssid ) );
1532 
1533 	drop:
1534 		free_iob ( iob );
1535 	}
1536 
1537 	return 0;
1538 }
1539 
1540 
1541 /**
1542  * Finish probe of 802.11 networks, returning best-signal network found
1543  *
1544  * @v ctx	Probe context
1545  * @ret wlan	Best-signal network found, or @c NULL if none were found
1546  *
1547  * If net80211_probe_start() was called with a particular SSID
1548  * parameter as filter, only a network with that SSID (matching
1549  * case-sensitively) can be returned from this function.
1550  */
1551 struct net80211_wlan *
net80211_probe_finish_best(struct net80211_probe_ctx * ctx)1552 net80211_probe_finish_best ( struct net80211_probe_ctx *ctx )
1553 {
1554 	struct net80211_wlan *best = NULL, *wlan;
1555 
1556 	if ( ! ctx )
1557 		return NULL;
1558 
1559 	list_for_each_entry ( wlan, ctx->beacons, list ) {
1560 		if ( ! best || best->signal < wlan->signal )
1561 			best = wlan;
1562 	}
1563 
1564 	if ( best )
1565 		list_del ( &best->list );
1566 	else
1567 		DBGC ( ctx->dev, "802.11 %p probe: found nothing for '%s'\n",
1568 		       ctx->dev, ctx->essid );
1569 
1570 	net80211_free_wlanlist ( ctx->beacons );
1571 
1572 	net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
1573 
1574 	if ( ctx->probe )
1575 		free_iob ( ctx->probe );
1576 
1577 	free ( ctx );
1578 
1579 	return best;
1580 }
1581 
1582 
1583 /**
1584  * Finish probe of 802.11 networks, returning all networks found
1585  *
1586  * @v ctx	Probe context
1587  * @ret list	List of net80211_wlan detailing networks found
1588  *
1589  * If net80211_probe_start() was called with a particular SSID
1590  * parameter as filter, this will always return either an empty or a
1591  * one-element list.
1592  */
net80211_probe_finish_all(struct net80211_probe_ctx * ctx)1593 struct list_head *net80211_probe_finish_all ( struct net80211_probe_ctx *ctx )
1594 {
1595 	struct list_head *beacons = ctx->beacons;
1596 
1597 	if ( ! ctx )
1598 		return NULL;
1599 
1600 	net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
1601 
1602 	if ( ctx->probe )
1603 		free_iob ( ctx->probe );
1604 
1605 	free ( ctx );
1606 
1607 	return beacons;
1608 }
1609 
1610 
1611 /**
1612  * Free WLAN structure
1613  *
1614  * @v wlan	WLAN structure to free
1615  */
net80211_free_wlan(struct net80211_wlan * wlan)1616 void net80211_free_wlan ( struct net80211_wlan *wlan )
1617 {
1618 	if ( wlan ) {
1619 		free_iob ( wlan->beacon );
1620 		free ( wlan );
1621 	}
1622 }
1623 
1624 
1625 /**
1626  * Free list of WLAN structures
1627  *
1628  * @v list	List of WLAN structures to free
1629  */
net80211_free_wlanlist(struct list_head * list)1630 void net80211_free_wlanlist ( struct list_head *list )
1631 {
1632 	struct net80211_wlan *wlan, *tmp;
1633 
1634 	if ( ! list )
1635 		return;
1636 
1637 	list_for_each_entry_safe ( wlan, tmp, list, list ) {
1638 		list_del ( &wlan->list );
1639 		net80211_free_wlan ( wlan );
1640 	}
1641 
1642 	free ( list );
1643 }
1644 
1645 
1646 /** Number of ticks to wait for replies to association management frames */
1647 #define ASSOC_TIMEOUT	TICKS_PER_SEC
1648 
1649 /** Number of times to try sending a particular association management frame */
1650 #define ASSOC_RETRIES	2
1651 
1652 /**
1653  * Step 802.11 association process
1654  *
1655  * @v proc	Association process
1656  */
net80211_step_associate(struct process * proc)1657 static void net80211_step_associate ( struct process *proc )
1658 {
1659 	struct net80211_device *dev =
1660 	    container_of ( proc, struct net80211_device, proc_assoc );
1661 	int rc = 0;
1662 	int status = dev->state & NET80211_STATUS_MASK;
1663 
1664 	/*
1665 	 * We use a sort of state machine implemented using bits in
1666 	 * the dev->state variable. At each call, we take the
1667 	 * logically first step that has not yet succeeded; either it
1668 	 * has not been tried yet, it's being retried, or it failed.
1669 	 * If it failed, we return an error indication; otherwise we
1670 	 * perform the step. If it succeeds, RX handling code will set
1671 	 * the appropriate status bit for us.
1672 	 *
1673 	 * Probe works a bit differently, since we have to step it
1674 	 * on every call instead of waiting for a packet to arrive
1675 	 * that will set the completion bit for us.
1676 	 */
1677 
1678 	/* If we're waiting for a reply, check for timeout condition */
1679 	if ( dev->state & NET80211_WAITING ) {
1680 		/* Sanity check */
1681 		if ( ! dev->associating )
1682 			return;
1683 
1684 		if ( currticks() - dev->ctx.assoc->last_packet > ASSOC_TIMEOUT ) {
1685 			/* Timed out - fail if too many retries, or retry */
1686 			dev->ctx.assoc->times_tried++;
1687 			if ( ++dev->ctx.assoc->times_tried > ASSOC_RETRIES ) {
1688 				rc = -ETIMEDOUT;
1689 				goto fail;
1690 			}
1691 		} else {
1692 			/* Didn't time out - let it keep going */
1693 			return;
1694 		}
1695 	} else {
1696 		if ( dev->state & NET80211_PROBED )
1697 			dev->ctx.assoc->times_tried = 0;
1698 	}
1699 
1700 	if ( ! ( dev->state & NET80211_PROBED ) ) {
1701 		/* state: probe */
1702 
1703 		if ( ! dev->ctx.probe ) {
1704 			/* start probe */
1705 			int active = fetch_intz_setting ( NULL,
1706 						&net80211_active_setting );
1707 			int band = dev->hw->bands;
1708 
1709 			if ( active )
1710 				band &= ~NET80211_BAND_BIT_5GHZ;
1711 
1712 			rc = net80211_prepare_probe ( dev, band, active );
1713 			if ( rc )
1714 				goto fail;
1715 
1716 			dev->ctx.probe = net80211_probe_start ( dev, dev->essid,
1717 								active );
1718 			if ( ! dev->ctx.probe ) {
1719 				dev->assoc_rc = -ENOMEM;
1720 				goto fail;
1721 			}
1722 		}
1723 
1724 		rc = net80211_probe_step ( dev->ctx.probe );
1725 		if ( ! rc ) {
1726 			return;	/* still going */
1727 		}
1728 
1729 		dev->associating = net80211_probe_finish_best ( dev->ctx.probe );
1730 		dev->ctx.probe = NULL;
1731 		if ( ! dev->associating ) {
1732 			if ( rc > 0 ) /* "successful" probe found nothing */
1733 				rc = -ETIMEDOUT;
1734 			goto fail;
1735 		}
1736 
1737 		/* If we probed using a broadcast SSID, record that
1738 		   fact for the settings applicator before we clobber
1739 		   it with the specific SSID we've chosen. */
1740 		if ( ! dev->essid[0] )
1741 			dev->state |= NET80211_AUTO_SSID;
1742 
1743 		DBGC ( dev, "802.11 %p found network %s (%s)\n", dev,
1744 		       dev->associating->essid,
1745 		       eth_ntoa ( dev->associating->bssid ) );
1746 
1747 		dev->ctx.assoc = zalloc ( sizeof ( *dev->ctx.assoc ) );
1748 		if ( ! dev->ctx.assoc ) {
1749 			rc = -ENOMEM;
1750 			goto fail;
1751 		}
1752 
1753 		dev->state |= NET80211_PROBED;
1754 		dev->ctx.assoc->method = IEEE80211_AUTH_OPEN_SYSTEM;
1755 
1756 		return;
1757 	}
1758 
1759 	/* Record time of sending the packet we're about to send, for timeout */
1760 	dev->ctx.assoc->last_packet = currticks();
1761 
1762 	if ( ! ( dev->state & NET80211_AUTHENTICATED ) ) {
1763 		/* state: prepare and authenticate */
1764 
1765 		if ( status != IEEE80211_STATUS_SUCCESS ) {
1766 			/* we tried authenticating already, but failed */
1767 			int method = dev->ctx.assoc->method;
1768 
1769 			if ( method == IEEE80211_AUTH_OPEN_SYSTEM &&
1770 			     ( status == IEEE80211_STATUS_AUTH_CHALL_INVALID ||
1771 			       status == IEEE80211_STATUS_AUTH_ALGO_UNSUPP ) ) {
1772 				/* Maybe this network uses Shared Key? */
1773 				dev->ctx.assoc->method =
1774 					IEEE80211_AUTH_SHARED_KEY;
1775 			} else {
1776 				goto fail;
1777 			}
1778 		}
1779 
1780 		DBGC ( dev, "802.11 %p authenticating with method %d\n", dev,
1781 		       dev->ctx.assoc->method );
1782 
1783 		rc = net80211_prepare_assoc ( dev, dev->associating );
1784 		if ( rc )
1785 			goto fail;
1786 
1787 		rc = net80211_send_auth ( dev, dev->associating,
1788 					  dev->ctx.assoc->method );
1789 		if ( rc )
1790 			goto fail;
1791 
1792 		return;
1793 	}
1794 
1795 	if ( ! ( dev->state & NET80211_ASSOCIATED ) ) {
1796 		/* state: associate */
1797 
1798 		if ( status != IEEE80211_STATUS_SUCCESS )
1799 			goto fail;
1800 
1801 		DBGC ( dev, "802.11 %p associating\n", dev );
1802 
1803 		if ( dev->handshaker && dev->handshaker->start &&
1804 		     ! dev->handshaker->started ) {
1805 			rc = dev->handshaker->start ( dev );
1806 			if ( rc < 0 )
1807 				goto fail;
1808 			dev->handshaker->started = 1;
1809 		}
1810 
1811 		rc = net80211_send_assoc ( dev, dev->associating );
1812 		if ( rc )
1813 			goto fail;
1814 
1815 		return;
1816 	}
1817 
1818 	if ( ! ( dev->state & NET80211_CRYPTO_SYNCED ) ) {
1819 		/* state: crypto sync */
1820 		DBGC ( dev, "802.11 %p security handshaking\n", dev );
1821 
1822 		if ( ! dev->handshaker || ! dev->handshaker->step ) {
1823 			dev->state |= NET80211_CRYPTO_SYNCED;
1824 			return;
1825 		}
1826 
1827 		rc = dev->handshaker->step ( dev );
1828 
1829 		if ( rc < 0 ) {
1830 			/* Only record the returned error if we're
1831 			   still marked as associated, because an
1832 			   asynchronous error will have already been
1833 			   reported to net80211_deauthenticate() and
1834 			   assoc_rc thereby set. */
1835 			if ( dev->state & NET80211_ASSOCIATED )
1836 				dev->assoc_rc = rc;
1837 			rc = 0;
1838 			goto fail;
1839 		}
1840 
1841 		if ( rc > 0 ) {
1842 			dev->assoc_rc = 0;
1843 			dev->state |= NET80211_CRYPTO_SYNCED;
1844 		}
1845 		return;
1846 	}
1847 
1848 	/* state: done! */
1849 	netdev_link_up ( dev->netdev );
1850 	dev->assoc_rc = 0;
1851 	dev->state &= ~NET80211_WORKING;
1852 
1853 	free ( dev->ctx.assoc );
1854 	dev->ctx.assoc = NULL;
1855 
1856 	net80211_free_wlan ( dev->associating );
1857 	dev->associating = NULL;
1858 
1859 	dev->rctl = rc80211_init ( dev );
1860 
1861 	process_del ( proc );
1862 
1863 	DBGC ( dev, "802.11 %p associated with %s (%s)\n", dev,
1864 	       dev->essid, eth_ntoa ( dev->bssid ) );
1865 
1866 	return;
1867 
1868  fail:
1869 	dev->state &= ~( NET80211_WORKING | NET80211_WAITING );
1870 	if ( rc )
1871 		dev->assoc_rc = rc;
1872 
1873 	netdev_link_err ( dev->netdev, dev->assoc_rc );
1874 
1875 	/* We never reach here from the middle of a probe, so we don't
1876 	   need to worry about freeing dev->ctx.probe. */
1877 
1878 	if ( dev->state & NET80211_PROBED ) {
1879 		free ( dev->ctx.assoc );
1880 		dev->ctx.assoc = NULL;
1881 	}
1882 
1883 	net80211_free_wlan ( dev->associating );
1884 	dev->associating = NULL;
1885 
1886 	process_del ( proc );
1887 
1888 	DBGC ( dev, "802.11 %p association failed (state=%04x): "
1889 	       "%s\n", dev, dev->state, strerror ( dev->assoc_rc ) );
1890 
1891 	/* Try it again: */
1892 	net80211_autoassociate ( dev );
1893 }
1894 
1895 /**
1896  * Check for 802.11 SSID or key updates
1897  *
1898  * This acts as a settings applicator; if the user changes netX/ssid,
1899  * and netX is currently open, the association task will be invoked
1900  * again. If the user changes the encryption key, the current security
1901  * handshaker will be asked to update its state to match; if that is
1902  * impossible without reassociation, we reassociate.
1903  */
net80211_check_settings_update(void)1904 static int net80211_check_settings_update ( void )
1905 {
1906 	struct net80211_device *dev;
1907 	char ssid[IEEE80211_MAX_SSID_LEN + 1];
1908 	int key_reassoc;
1909 
1910 	list_for_each_entry ( dev, &net80211_devices, list ) {
1911 		if ( ! ( dev->netdev->state & NETDEV_OPEN ) )
1912 			continue;
1913 
1914 		key_reassoc = 0;
1915 		if ( dev->handshaker && dev->handshaker->change_key &&
1916 		     dev->handshaker->change_key ( dev ) < 0 )
1917 			key_reassoc = 1;
1918 
1919 		fetch_string_setting ( netdev_settings ( dev->netdev ),
1920 				       &net80211_ssid_setting, ssid,
1921 				       IEEE80211_MAX_SSID_LEN + 1 );
1922 
1923 		if ( key_reassoc ||
1924 		     ( ! ( ! ssid[0] && ( dev->state & NET80211_AUTO_SSID ) ) &&
1925 		       strcmp ( ssid, dev->essid ) != 0 ) ) {
1926 			DBGC ( dev, "802.11 %p updating association: "
1927 			       "%s -> %s\n", dev, dev->essid, ssid );
1928 			net80211_autoassociate ( dev );
1929 		}
1930 	}
1931 
1932 	return 0;
1933 }
1934 
1935 /**
1936  * Start 802.11 association process
1937  *
1938  * @v dev	802.11 device
1939  *
1940  * If the association process is running, it will be restarted.
1941  */
net80211_autoassociate(struct net80211_device * dev)1942 void net80211_autoassociate ( struct net80211_device *dev )
1943 {
1944 	if ( ! ( dev->state & NET80211_WORKING ) ) {
1945 		DBGC2 ( dev, "802.11 %p spawning association process\n", dev );
1946 		process_add ( &dev->proc_assoc );
1947 	} else {
1948 		DBGC2 ( dev, "802.11 %p restarting association\n", dev );
1949 	}
1950 
1951 	/* Clean up everything an earlier association process might
1952 	   have been in the middle of using */
1953 	if ( dev->associating )
1954 		net80211_free_wlan ( dev->associating );
1955 
1956 	if ( ! ( dev->state & NET80211_PROBED ) )
1957 		net80211_free_wlan (
1958 			net80211_probe_finish_best ( dev->ctx.probe ) );
1959 	else
1960 		free ( dev->ctx.assoc );
1961 
1962 	/* Reset to a clean state */
1963 	fetch_string_setting ( netdev_settings ( dev->netdev ),
1964 			       &net80211_ssid_setting, dev->essid,
1965 			       IEEE80211_MAX_SSID_LEN + 1 );
1966 	dev->ctx.probe = NULL;
1967 	dev->associating = NULL;
1968 	dev->assoc_rc = 0;
1969 	net80211_set_state ( dev, NET80211_PROBED, NET80211_WORKING, 0 );
1970 }
1971 
1972 /**
1973  * Pick TX rate for RTS/CTS packets based on data rate
1974  *
1975  * @v dev	802.11 device
1976  *
1977  * The RTS/CTS rate is the fastest TX rate marked as "basic" that is
1978  * not faster than the data rate.
1979  */
net80211_set_rtscts_rate(struct net80211_device * dev)1980 static void net80211_set_rtscts_rate ( struct net80211_device *dev )
1981 {
1982 	u16 datarate = dev->rates[dev->rate];
1983 	u16 rtsrate = 0;
1984 	int rts_idx = -1;
1985 	int i;
1986 
1987 	for ( i = 0; i < dev->nr_rates; i++ ) {
1988 		u16 rate = dev->rates[i];
1989 
1990 		if ( ! ( dev->basic_rates & ( 1 << i ) ) || rate > datarate )
1991 			continue;
1992 
1993 		if ( rate > rtsrate ) {
1994 			rtsrate = rate;
1995 			rts_idx = i;
1996 		}
1997 	}
1998 
1999 	/* If this is in initialization, we might not have any basic
2000 	   rates; just use the first data rate in that case. */
2001 	if ( rts_idx < 0 )
2002 		rts_idx = 0;
2003 
2004 	dev->rtscts_rate = rts_idx;
2005 }
2006 
2007 /**
2008  * Set data transmission rate for 802.11 device
2009  *
2010  * @v dev	802.11 device
2011  * @v rate	Rate to set, as index into @c dev->rates array
2012  */
net80211_set_rate_idx(struct net80211_device * dev,int rate)2013 void net80211_set_rate_idx ( struct net80211_device *dev, int rate )
2014 {
2015 	assert ( dev->netdev->state & NETDEV_OPEN );
2016 
2017 	if ( rate >= 0 && rate < dev->nr_rates && rate != dev->rate ) {
2018 		DBGC2 ( dev, "802.11 %p changing rate from %d->%d Mbps\n",
2019 			dev, dev->rates[dev->rate] / 10,
2020 			dev->rates[rate] / 10 );
2021 
2022 		dev->rate = rate;
2023 		net80211_set_rtscts_rate ( dev );
2024 		dev->op->config ( dev, NET80211_CFG_RATE );
2025 	}
2026 }
2027 
2028 /**
2029  * Configure 802.11 device to transmit on a certain channel
2030  *
2031  * @v dev	802.11 device
2032  * @v channel	Channel number (1-11 for 2.4GHz) to transmit on
2033  */
net80211_change_channel(struct net80211_device * dev,int channel)2034 int net80211_change_channel ( struct net80211_device *dev, int channel )
2035 {
2036 	int i, oldchan = dev->channel;
2037 
2038 	assert ( dev->netdev->state & NETDEV_OPEN );
2039 
2040 	for ( i = 0; i < dev->nr_channels; i++ ) {
2041 		if ( dev->channels[i].channel_nr == channel ) {
2042 			dev->channel = i;
2043 			break;
2044 		}
2045 	}
2046 
2047 	if ( i == dev->nr_channels )
2048 		return -ENOENT;
2049 
2050 	if ( i != oldchan )
2051 		return dev->op->config ( dev, NET80211_CFG_CHANNEL );
2052 
2053 	return 0;
2054 }
2055 
2056 /**
2057  * Prepare 802.11 device channel and rate set for scanning
2058  *
2059  * @v dev	802.11 device
2060  * @v band	RF band(s) on which to prepare for scanning
2061  * @v active	Whether the scanning will be active
2062  * @ret rc	Return status code
2063  */
net80211_prepare_probe(struct net80211_device * dev,int band,int active)2064 int net80211_prepare_probe ( struct net80211_device *dev, int band,
2065 			     int active )
2066 {
2067 	assert ( dev->netdev->state & NETDEV_OPEN );
2068 
2069 	if ( active && ( band & NET80211_BAND_BIT_5GHZ ) ) {
2070 		DBGC ( dev, "802.11 %p cannot perform active scanning on "
2071 		       "5GHz band\n", dev );
2072 		return -EINVAL_ACTIVE_SCAN;
2073 	}
2074 
2075 	if ( band == 0 ) {
2076 		/* This can happen for a 5GHz-only card with 5GHz
2077 		   scanning masked out by an active request. */
2078 		DBGC ( dev, "802.11 %p asked to prepare for scanning nothing\n",
2079 		       dev );
2080 		return -EINVAL_ACTIVE_SCAN;
2081 	}
2082 
2083 	dev->nr_channels = 0;
2084 
2085 	if ( active )
2086 		net80211_add_channels ( dev, 1, 11, NET80211_REG_TXPOWER );
2087 	else {
2088 		if ( band & NET80211_BAND_BIT_2GHZ )
2089 			net80211_add_channels ( dev, 1, 14,
2090 						NET80211_REG_TXPOWER );
2091 		if ( band & NET80211_BAND_BIT_5GHZ )
2092 			net80211_add_channels ( dev, 36, 8,
2093 						NET80211_REG_TXPOWER );
2094 	}
2095 
2096 	net80211_filter_hw_channels ( dev );
2097 
2098 	/* Use channel 1 for now */
2099 	dev->channel = 0;
2100 	dev->op->config ( dev, NET80211_CFG_CHANNEL );
2101 
2102 	/* Always do active probes at lowest (presumably first) speed */
2103 	dev->rate = 0;
2104 	dev->nr_rates = 1;
2105 	dev->rates[0] = dev->hw->rates[dev->channels[0].band][0];
2106 	dev->op->config ( dev, NET80211_CFG_RATE );
2107 
2108 	return 0;
2109 }
2110 
2111 /**
2112  * Prepare 802.11 device channel and rate set for communication
2113  *
2114  * @v dev	802.11 device
2115  * @v wlan	WLAN to prepare for communication with
2116  * @ret rc	Return status code
2117  */
net80211_prepare_assoc(struct net80211_device * dev,struct net80211_wlan * wlan)2118 int net80211_prepare_assoc ( struct net80211_device *dev,
2119 			     struct net80211_wlan *wlan )
2120 {
2121 	struct ieee80211_frame *hdr = wlan->beacon->data;
2122 	struct ieee80211_beacon *beacon =
2123 		( struct ieee80211_beacon * ) hdr->data;
2124 	struct net80211_handshaker *handshaker;
2125 	int rc;
2126 
2127 	assert ( dev->netdev->state & NETDEV_OPEN );
2128 
2129 	net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
2130 	memcpy ( dev->bssid, wlan->bssid, ETH_ALEN );
2131 	strcpy ( dev->essid, wlan->essid );
2132 
2133 	free ( dev->rsn_ie );
2134 	dev->rsn_ie = NULL;
2135 
2136 	dev->last_beacon_timestamp = beacon->timestamp;
2137 	dev->tx_beacon_interval = 1024 * beacon->beacon_interval;
2138 
2139 	/* Barring an IE that tells us the channel outright, assume
2140 	   the channel we heard this AP best on is the channel it's
2141 	   communicating on. */
2142 	net80211_change_channel ( dev, wlan->channel );
2143 
2144 	rc = net80211_process_capab ( dev, beacon->capability );
2145 	if ( rc )
2146 		return rc;
2147 
2148 	rc = net80211_process_ie ( dev, beacon->info_element,
2149 				   wlan->beacon->tail );
2150 	if ( rc )
2151 		return rc;
2152 
2153 	/* Associate at the lowest rate so we know it'll get through */
2154 	dev->rate = 0;
2155 	dev->op->config ( dev, NET80211_CFG_RATE );
2156 
2157 	/* Free old handshaker and crypto, if they exist */
2158 	if ( dev->handshaker && dev->handshaker->stop &&
2159 	     dev->handshaker->started )
2160 		dev->handshaker->stop ( dev );
2161 	free ( dev->handshaker );
2162 	dev->handshaker = NULL;
2163 	free ( dev->crypto );
2164 	free ( dev->gcrypto );
2165 	dev->crypto = dev->gcrypto = NULL;
2166 
2167 	/* Find new security handshaker to use */
2168 	for_each_table_entry ( handshaker, NET80211_HANDSHAKERS ) {
2169 		if ( handshaker->protocol == wlan->handshaking ) {
2170 			dev->handshaker = zalloc ( sizeof ( *handshaker ) +
2171 						   handshaker->priv_len );
2172 			if ( ! dev->handshaker )
2173 				return -ENOMEM;
2174 
2175 			memcpy ( dev->handshaker, handshaker,
2176 				 sizeof ( *handshaker ) );
2177 			dev->handshaker->priv = ( ( void * ) dev->handshaker +
2178 						  sizeof ( *handshaker ) );
2179 			break;
2180 		}
2181 	}
2182 
2183 	if ( ( wlan->handshaking != NET80211_SECPROT_NONE ) &&
2184 	     ! dev->handshaker ) {
2185 		DBGC ( dev, "802.11 %p no support for handshaking scheme %d\n",
2186 		       dev, wlan->handshaking );
2187 		return -( ENOTSUP | ( wlan->handshaking << 8 ) );
2188 	}
2189 
2190 	/* Initialize security handshaker */
2191 	if ( dev->handshaker ) {
2192 		rc = dev->handshaker->init ( dev );
2193 		if ( rc < 0 )
2194 			return rc;
2195 	}
2196 
2197 	return 0;
2198 }
2199 
2200 /**
2201  * Send 802.11 initial authentication frame
2202  *
2203  * @v dev	802.11 device
2204  * @v wlan	WLAN to authenticate with
2205  * @v method	Authentication method
2206  * @ret rc	Return status code
2207  *
2208  * @a method may be 0 for Open System authentication or 1 for Shared
2209  * Key authentication. Open System provides no security in association
2210  * whatsoever, relying on encryption for confidentiality, but Shared
2211  * Key actively introduces security problems and is very rarely used.
2212  */
net80211_send_auth(struct net80211_device * dev,struct net80211_wlan * wlan,int method)2213 int net80211_send_auth ( struct net80211_device *dev,
2214 			 struct net80211_wlan *wlan, int method )
2215 {
2216 	struct io_buffer *iob = alloc_iob ( 64 );
2217 	struct ieee80211_auth *auth;
2218 
2219 	net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
2220 	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
2221 	auth = iob_put ( iob, sizeof ( *auth ) );
2222 	auth->algorithm = method;
2223 	auth->tx_seq = 1;
2224 	auth->status = 0;
2225 
2226 	return net80211_tx_mgmt ( dev, IEEE80211_STYPE_AUTH, wlan->bssid, iob );
2227 }
2228 
2229 /**
2230  * Handle receipt of 802.11 authentication frame
2231  *
2232  * @v dev	802.11 device
2233  * @v iob	I/O buffer
2234  *
2235  * If the authentication method being used is Shared Key, and the
2236  * frame that was received included challenge text, the frame is
2237  * encrypted using the cryptosystem currently in effect and sent back
2238  * to the AP to complete the authentication.
2239  */
net80211_handle_auth(struct net80211_device * dev,struct io_buffer * iob)2240 static void net80211_handle_auth ( struct net80211_device *dev,
2241 				   struct io_buffer *iob )
2242 {
2243 	struct ieee80211_frame *hdr = iob->data;
2244 	struct ieee80211_auth *auth =
2245 	    ( struct ieee80211_auth * ) hdr->data;
2246 
2247 	if ( auth->tx_seq & 1 ) {
2248 		DBGC ( dev, "802.11 %p authentication received improperly "
2249 		       "directed frame (seq. %d)\n", dev, auth->tx_seq );
2250 		net80211_set_state ( dev, NET80211_WAITING, 0,
2251 				     IEEE80211_STATUS_FAILURE );
2252 		return;
2253 	}
2254 
2255 	if ( auth->status != IEEE80211_STATUS_SUCCESS ) {
2256 		DBGC ( dev, "802.11 %p authentication failed: status %d\n",
2257 		       dev, auth->status );
2258 		net80211_set_state ( dev, NET80211_WAITING, 0,
2259 				     auth->status );
2260 		return;
2261 	}
2262 
2263 	if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY && ! dev->crypto ) {
2264 		DBGC ( dev, "802.11 %p can't perform shared-key authentication "
2265 		       "without a cryptosystem\n", dev );
2266 		net80211_set_state ( dev, NET80211_WAITING, 0,
2267 				     IEEE80211_STATUS_FAILURE );
2268 		return;
2269 	}
2270 
2271 	if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY &&
2272 	     auth->tx_seq == 2 ) {
2273 		/* Since the iob we got is going to be freed as soon
2274 		   as we return, we can do some in-place
2275 		   modification. */
2276 		auth->tx_seq = 3;
2277 		auth->status = 0;
2278 
2279 		memcpy ( hdr->addr2, hdr->addr1, ETH_ALEN );
2280 		memcpy ( hdr->addr1, hdr->addr3, ETH_ALEN );
2281 
2282 		netdev_tx ( dev->netdev,
2283 			    dev->crypto->encrypt ( dev->crypto, iob ) );
2284 		return;
2285 	}
2286 
2287 	net80211_set_state ( dev, NET80211_WAITING, NET80211_AUTHENTICATED,
2288 			     IEEE80211_STATUS_SUCCESS );
2289 
2290 	return;
2291 }
2292 
2293 /**
2294  * Send 802.11 association frame
2295  *
2296  * @v dev	802.11 device
2297  * @v wlan	WLAN to associate with
2298  * @ret rc	Return status code
2299  */
net80211_send_assoc(struct net80211_device * dev,struct net80211_wlan * wlan)2300 int net80211_send_assoc ( struct net80211_device *dev,
2301 			  struct net80211_wlan *wlan )
2302 {
2303 	struct io_buffer *iob = alloc_iob ( 128 );
2304 	struct ieee80211_assoc_req *assoc;
2305 	union ieee80211_ie *ie;
2306 
2307 	net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
2308 
2309 	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
2310 	assoc = iob->data;
2311 
2312 	assoc->capability = IEEE80211_CAPAB_MANAGED;
2313 	if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE ) )
2314 		assoc->capability |= IEEE80211_CAPAB_SHORT_PMBL;
2315 	if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT ) )
2316 		assoc->capability |= IEEE80211_CAPAB_SHORT_SLOT;
2317 	if ( wlan->crypto )
2318 		assoc->capability |= IEEE80211_CAPAB_PRIVACY;
2319 
2320 	assoc->listen_interval = 1;
2321 
2322 	ie = net80211_marshal_request_info ( dev, assoc->info_element );
2323 
2324 	DBGP ( "802.11 %p about to send association request:\n", dev );
2325 	DBGP_HD ( iob->data, ( void * ) ie - iob->data );
2326 
2327 	iob_put ( iob, ( void * ) ie - iob->data );
2328 
2329 	return net80211_tx_mgmt ( dev, IEEE80211_STYPE_ASSOC_REQ,
2330 				  wlan->bssid, iob );
2331 }
2332 
2333 /**
2334  * Handle receipt of 802.11 association reply frame
2335  *
2336  * @v dev	802.11 device
2337  * @v iob	I/O buffer
2338  */
net80211_handle_assoc_reply(struct net80211_device * dev,struct io_buffer * iob)2339 static void net80211_handle_assoc_reply ( struct net80211_device *dev,
2340 					  struct io_buffer *iob )
2341 {
2342 	struct ieee80211_frame *hdr = iob->data;
2343 	struct ieee80211_assoc_resp *assoc =
2344 		( struct ieee80211_assoc_resp * ) hdr->data;
2345 
2346 	net80211_process_capab ( dev, assoc->capability );
2347 	net80211_process_ie ( dev, assoc->info_element, iob->tail );
2348 
2349 	if ( assoc->status != IEEE80211_STATUS_SUCCESS ) {
2350 		DBGC ( dev, "802.11 %p association failed: status %d\n",
2351 		       dev, assoc->status );
2352 		net80211_set_state ( dev, NET80211_WAITING, 0,
2353 				     assoc->status );
2354 		return;
2355 	}
2356 
2357 	/* ESSID was filled before the association request was sent */
2358 	memcpy ( dev->bssid, hdr->addr3, ETH_ALEN );
2359 	dev->aid = assoc->aid;
2360 
2361 	net80211_set_state ( dev, NET80211_WAITING, NET80211_ASSOCIATED,
2362 			     IEEE80211_STATUS_SUCCESS );
2363 }
2364 
2365 
2366 /**
2367  * Send 802.11 disassociation frame
2368  *
2369  * @v dev	802.11 device
2370  * @v reason	Reason for disassociation
2371  * @v deauth	If TRUE, send deauthentication instead of disassociation
2372  * @ret rc	Return status code
2373  */
net80211_send_disassoc(struct net80211_device * dev,int reason,int deauth)2374 static int net80211_send_disassoc ( struct net80211_device *dev, int reason,
2375 				    int deauth )
2376 {
2377 	struct io_buffer *iob = alloc_iob ( 64 );
2378 	struct ieee80211_disassoc *disassoc;
2379 
2380 	if ( ! ( dev->state & NET80211_ASSOCIATED ) )
2381 		return -EINVAL;
2382 
2383 	net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
2384 	iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
2385 	disassoc = iob_put ( iob, sizeof ( *disassoc ) );
2386 	disassoc->reason = reason;
2387 
2388 	return net80211_tx_mgmt ( dev, deauth ? IEEE80211_STYPE_DEAUTH :
2389 				  IEEE80211_STYPE_DISASSOC, dev->bssid, iob );
2390 }
2391 
2392 
2393 /**
2394  * Deauthenticate from current network and try again
2395  *
2396  * @v dev	802.11 device
2397  * @v rc	Return status code indicating reason
2398  *
2399  * The deauthentication will be sent using an 802.11 "unspecified
2400  * reason", as is common, but @a rc will be set as a link-up
2401  * error to aid the user in debugging.
2402  */
net80211_deauthenticate(struct net80211_device * dev,int rc)2403 void net80211_deauthenticate ( struct net80211_device *dev, int rc )
2404 {
2405 	net80211_send_disassoc ( dev, IEEE80211_REASON_UNSPECIFIED, 1 );
2406 	dev->assoc_rc = rc;
2407 	netdev_link_err ( dev->netdev, rc );
2408 
2409 	net80211_autoassociate ( dev );
2410 }
2411 
2412 
2413 /** Smoothing factor (1-7) for link quality calculation */
2414 #define LQ_SMOOTH	7
2415 
2416 /**
2417  * Update link quality information based on received beacon
2418  *
2419  * @v dev	802.11 device
2420  * @v iob	I/O buffer containing beacon
2421  * @ret rc	Return status code
2422  */
net80211_update_link_quality(struct net80211_device * dev,struct io_buffer * iob)2423 static void net80211_update_link_quality ( struct net80211_device *dev,
2424 					   struct io_buffer *iob )
2425 {
2426 	struct ieee80211_frame *hdr = iob->data;
2427 	struct ieee80211_beacon *beacon;
2428 	u32 dt, rxi;
2429 
2430 	if ( ! ( dev->state & NET80211_ASSOCIATED ) )
2431 		return;
2432 
2433 	beacon = ( struct ieee80211_beacon * ) hdr->data;
2434 	dt = ( u32 ) ( beacon->timestamp - dev->last_beacon_timestamp );
2435 	rxi = dev->rx_beacon_interval;
2436 
2437 	rxi = ( LQ_SMOOTH * rxi ) + ( ( 8 - LQ_SMOOTH ) * dt );
2438 	dev->rx_beacon_interval = rxi >> 3;
2439 
2440 	dev->last_beacon_timestamp = beacon->timestamp;
2441 }
2442 
2443 
2444 /**
2445  * Handle receipt of 802.11 management frame
2446  *
2447  * @v dev	802.11 device
2448  * @v iob	I/O buffer
2449  * @v signal	Signal strength of received frame
2450  */
net80211_handle_mgmt(struct net80211_device * dev,struct io_buffer * iob,int signal)2451 static void net80211_handle_mgmt ( struct net80211_device *dev,
2452 				   struct io_buffer *iob, int signal )
2453 {
2454 	struct ieee80211_frame *hdr = iob->data;
2455 	struct ieee80211_disassoc *disassoc;
2456 	u16 stype = hdr->fc & IEEE80211_FC_SUBTYPE;
2457 	int keep = 0;
2458 	int is_deauth = ( stype == IEEE80211_STYPE_DEAUTH );
2459 
2460 	if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_MGMT ) {
2461 		free_iob ( iob );
2462 		return;		/* only handle management frames */
2463 	}
2464 
2465 	switch ( stype ) {
2466 		/* We reconnect on deauthentication and disassociation. */
2467 	case IEEE80211_STYPE_DEAUTH:
2468 	case IEEE80211_STYPE_DISASSOC:
2469 		disassoc = ( struct ieee80211_disassoc * ) hdr->data;
2470 		net80211_set_state ( dev, is_deauth ? NET80211_AUTHENTICATED :
2471 				     NET80211_ASSOCIATED, 0,
2472 				     NET80211_IS_REASON | disassoc->reason );
2473 		DBGC ( dev, "802.11 %p %s: reason %d\n",
2474 		       dev, is_deauth ? "deauthenticated" : "disassociated",
2475 		       disassoc->reason );
2476 
2477 		/* Try to reassociate, in case it's transient. */
2478 		net80211_autoassociate ( dev );
2479 
2480 		break;
2481 
2482 		/* We handle authentication and association. */
2483 	case IEEE80211_STYPE_AUTH:
2484 		if ( ! ( dev->state & NET80211_AUTHENTICATED ) )
2485 			net80211_handle_auth ( dev, iob );
2486 		break;
2487 
2488 	case IEEE80211_STYPE_ASSOC_RESP:
2489 	case IEEE80211_STYPE_REASSOC_RESP:
2490 		if ( ! ( dev->state & NET80211_ASSOCIATED ) )
2491 			net80211_handle_assoc_reply ( dev, iob );
2492 		break;
2493 
2494 		/* We pass probes and beacons onto network scanning
2495 		   code. Pass actions for future extensibility. */
2496 	case IEEE80211_STYPE_BEACON:
2497 		net80211_update_link_quality ( dev, iob );
2498 		/* fall through */
2499 	case IEEE80211_STYPE_PROBE_RESP:
2500 	case IEEE80211_STYPE_ACTION:
2501 		if ( dev->keep_mgmt ) {
2502 			struct net80211_rx_info *rxinf;
2503 			rxinf = zalloc ( sizeof ( *rxinf ) );
2504 			if ( ! rxinf ) {
2505 				DBGC ( dev, "802.11 %p out of memory\n", dev );
2506 				break;
2507 			}
2508 			rxinf->signal = signal;
2509 			list_add_tail ( &iob->list, &dev->mgmt_queue );
2510 			list_add_tail ( &rxinf->list, &dev->mgmt_info_queue );
2511 			keep = 1;
2512 		}
2513 		break;
2514 
2515 	case IEEE80211_STYPE_PROBE_REQ:
2516 		/* Some nodes send these broadcast. Ignore them. */
2517 		break;
2518 
2519 	case IEEE80211_STYPE_ASSOC_REQ:
2520 	case IEEE80211_STYPE_REASSOC_REQ:
2521 		/* We should never receive these, only send them. */
2522 		DBGC ( dev, "802.11 %p received strange management request "
2523 		       "(%04x)\n", dev, stype );
2524 		break;
2525 
2526 	default:
2527 		DBGC ( dev, "802.11 %p received unimplemented management "
2528 		       "packet (%04x)\n", dev, stype );
2529 		break;
2530 	}
2531 
2532 	if ( ! keep )
2533 		free_iob ( iob );
2534 }
2535 
2536 /* ---------- Packet handling functions ---------- */
2537 
2538 /**
2539  * Free buffers used by 802.11 fragment cache entry
2540  *
2541  * @v dev	802.11 device
2542  * @v fcid	Fragment cache entry index
2543  *
2544  * After this function, the referenced entry will be marked unused.
2545  */
net80211_free_frags(struct net80211_device * dev,int fcid)2546 static void net80211_free_frags ( struct net80211_device *dev, int fcid )
2547 {
2548 	int j;
2549 	struct net80211_frag_cache *frag = &dev->frags[fcid];
2550 
2551 	for ( j = 0; j < 16; j++ ) {
2552 		if ( frag->iob[j] ) {
2553 			free_iob ( frag->iob[j] );
2554 			frag->iob[j] = NULL;
2555 		}
2556 	}
2557 
2558 	frag->seqnr = 0;
2559 	frag->start_ticks = 0;
2560 	frag->in_use = 0;
2561 }
2562 
2563 /**
2564  * Accumulate 802.11 fragments into one I/O buffer
2565  *
2566  * @v dev	802.11 device
2567  * @v fcid	Fragment cache entry index
2568  * @v nfrags	Number of fragments received
2569  * @v size	Sum of sizes of all fragments, including headers
2570  * @ret iob	I/O buffer containing reassembled packet
2571  *
2572  * This function does not free the fragment buffers.
2573  */
net80211_accum_frags(struct net80211_device * dev,int fcid,int nfrags,int size)2574 static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
2575 						int fcid, int nfrags, int size )
2576 {
2577 	struct net80211_frag_cache *frag = &dev->frags[fcid];
2578 	int hdrsize = IEEE80211_TYP_FRAME_HEADER_LEN;
2579 	int nsize = size - hdrsize * ( nfrags - 1 );
2580 	int i;
2581 
2582 	struct io_buffer *niob = alloc_iob ( nsize );
2583 	struct ieee80211_frame *hdr;
2584 
2585 	/* Add the header from the first one... */
2586 	memcpy ( iob_put ( niob, hdrsize ), frag->iob[0]->data, hdrsize );
2587 
2588 	/* ... and all the data from all of them. */
2589 	for ( i = 0; i < nfrags; i++ ) {
2590 		int len = iob_len ( frag->iob[i] ) - hdrsize;
2591 		memcpy ( iob_put ( niob, len ),
2592 			 frag->iob[i]->data + hdrsize, len );
2593 	}
2594 
2595 	/* Turn off the fragment bit. */
2596 	hdr = niob->data;
2597 	hdr->fc &= ~IEEE80211_FC_MORE_FRAG;
2598 
2599 	return niob;
2600 }
2601 
2602 /**
2603  * Handle receipt of 802.11 fragment
2604  *
2605  * @v dev	802.11 device
2606  * @v iob	I/O buffer containing fragment
2607  * @v signal	Signal strength with which fragment was received
2608  */
net80211_rx_frag(struct net80211_device * dev,struct io_buffer * iob,int signal)2609 static void net80211_rx_frag ( struct net80211_device *dev,
2610 			       struct io_buffer *iob, int signal )
2611 {
2612 	struct ieee80211_frame *hdr = iob->data;
2613 	int fragnr = IEEE80211_FRAG ( hdr->seq );
2614 
2615 	if ( fragnr == 0 && ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
2616 		/* start a frag cache entry */
2617 		int i, newest = -1;
2618 		u32 curr_ticks = currticks(), newest_ticks = 0;
2619 		u32 timeout = ticks_per_sec() * NET80211_FRAG_TIMEOUT;
2620 
2621 		for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
2622 			if ( dev->frags[i].in_use == 0 )
2623 				break;
2624 
2625 			if ( dev->frags[i].start_ticks + timeout >=
2626 			     curr_ticks ) {
2627 				net80211_free_frags ( dev, i );
2628 				break;
2629 			}
2630 
2631 			if ( dev->frags[i].start_ticks > newest_ticks ) {
2632 				newest = i;
2633 				newest_ticks = dev->frags[i].start_ticks;
2634 			}
2635 		}
2636 
2637 		/* If we're being sent more concurrent fragmented
2638 		   packets than we can handle, drop the newest so the
2639 		   older ones have time to complete. */
2640 		if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
2641 			i = newest;
2642 			net80211_free_frags ( dev, i );
2643 		}
2644 
2645 		dev->frags[i].in_use = 1;
2646 		dev->frags[i].seqnr = IEEE80211_SEQNR ( hdr->seq );
2647 		dev->frags[i].start_ticks = currticks();
2648 		dev->frags[i].iob[0] = iob;
2649 		return;
2650 	} else {
2651 		int i;
2652 		for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
2653 			if ( dev->frags[i].in_use && dev->frags[i].seqnr ==
2654 			     IEEE80211_SEQNR ( hdr->seq ) )
2655 				break;
2656 		}
2657 		if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
2658 			/* Drop non-first not-in-cache fragments */
2659 			DBGC ( dev, "802.11 %p dropped fragment fc=%04x "
2660 			       "seq=%04x\n", dev, hdr->fc, hdr->seq );
2661 			free_iob ( iob );
2662 			return;
2663 		}
2664 
2665 		dev->frags[i].iob[fragnr] = iob;
2666 
2667 		if ( ! ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
2668 			int j, size = 0;
2669 			for ( j = 0; j < fragnr; j++ ) {
2670 				size += iob_len ( dev->frags[i].iob[j] );
2671 				if ( dev->frags[i].iob[j] == NULL )
2672 					break;
2673 			}
2674 			if ( j == fragnr ) {
2675 				/* We've got everything */
2676 				struct io_buffer *niob =
2677 				    net80211_accum_frags ( dev, i, fragnr,
2678 							   size );
2679 				net80211_free_frags ( dev, i );
2680 				net80211_rx ( dev, niob, signal, 0 );
2681 			} else {
2682 				DBGC ( dev, "802.11 %p dropping fragmented "
2683 				       "packet due to out-of-order arrival, "
2684 				       "fc=%04x seq=%04x\n", dev, hdr->fc,
2685 				       hdr->seq );
2686 				net80211_free_frags ( dev, i );
2687 			}
2688 		}
2689 	}
2690 }
2691 
2692 /**
2693  * Handle receipt of 802.11 frame
2694  *
2695  * @v dev	802.11 device
2696  * @v iob	I/O buffer
2697  * @v signal	Received signal strength
2698  * @v rate	Bitrate at which frame was received, in 100 kbps units
2699  *
2700  * If the rate or signal is unknown, 0 should be passed.
2701  */
net80211_rx(struct net80211_device * dev,struct io_buffer * iob,int signal,u16 rate)2702 void net80211_rx ( struct net80211_device *dev, struct io_buffer *iob,
2703 		   int signal, u16 rate )
2704 {
2705 	struct ieee80211_frame *hdr = iob->data;
2706 	u16 type = hdr->fc & IEEE80211_FC_TYPE;
2707 	if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION )
2708 		goto drop;	/* drop invalid-version packets */
2709 
2710 	if ( type == IEEE80211_TYPE_CTRL )
2711 		goto drop;	/* we don't handle control packets,
2712 				   the hardware does */
2713 
2714 	if ( dev->last_rx_seq == hdr->seq )
2715 		goto drop;	/* avoid duplicate packet */
2716 	dev->last_rx_seq = hdr->seq;
2717 
2718 	if ( dev->hw->flags & NET80211_HW_RX_HAS_FCS ) {
2719 		/* discard the FCS */
2720 		iob_unput ( iob, 4 );
2721 	}
2722 
2723 	/* Only decrypt packets from our BSSID, to avoid spurious errors */
2724 	if ( ( hdr->fc & IEEE80211_FC_PROTECTED ) &&
2725 	     ! memcmp ( hdr->addr2, dev->bssid, ETH_ALEN ) ) {
2726 		/* Decrypt packet; record and drop if it fails */
2727 		struct io_buffer *niob;
2728 		struct net80211_crypto *crypto = dev->crypto;
2729 
2730 		if ( ! dev->crypto ) {
2731 			DBGC ( dev, "802.11 %p cannot decrypt packet "
2732 			       "without a cryptosystem\n", dev );
2733 			goto drop_crypt;
2734 		}
2735 
2736 		if ( ( hdr->addr1[0] & 1 ) && dev->gcrypto ) {
2737 			/* Use group decryption if needed */
2738 			crypto = dev->gcrypto;
2739 		}
2740 
2741 		niob = crypto->decrypt ( crypto, iob );
2742 		if ( ! niob ) {
2743 			DBGC ( dev, "802.11 %p decryption error\n", dev );
2744 			goto drop_crypt;
2745 		}
2746 		free_iob ( iob );
2747 		iob = niob;
2748 	}
2749 
2750 	dev->last_signal = signal;
2751 
2752 	/* Fragments go into the frag cache or get dropped. */
2753 	if ( IEEE80211_FRAG ( hdr->seq ) != 0
2754 	     || ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
2755 		net80211_rx_frag ( dev, iob, signal );
2756 		return;
2757 	}
2758 
2759 	/* Management frames get handled, enqueued, or dropped. */
2760 	if ( type == IEEE80211_TYPE_MGMT ) {
2761 		net80211_handle_mgmt ( dev, iob, signal );
2762 		return;
2763 	}
2764 
2765 	/* Data frames get dropped or sent to the net_device. */
2766 	if ( ( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA )
2767 		goto drop;	/* drop QoS, CFP, or null data packets */
2768 
2769 	/* Update rate-control algorithm */
2770 	if ( dev->rctl )
2771 		rc80211_update_rx ( dev, hdr->fc & IEEE80211_FC_RETRY, rate );
2772 
2773 	/* Pass packet onward */
2774 	if ( dev->state & NET80211_ASSOCIATED ) {
2775 		netdev_rx ( dev->netdev, iob );
2776 		return;
2777 	}
2778 
2779 	/* No association? Drop it. */
2780 	goto drop;
2781 
2782  drop_crypt:
2783 	netdev_rx_err ( dev->netdev, NULL, EINVAL_CRYPTO_REQUEST );
2784  drop:
2785 	DBGC2 ( dev, "802.11 %p dropped packet fc=%04x seq=%04x\n", dev,
2786 		hdr->fc, hdr->seq );
2787 	free_iob ( iob );
2788 	return;
2789 }
2790 
2791 /** Indicate an error in receiving a packet
2792  *
2793  * @v dev	802.11 device
2794  * @v iob	I/O buffer with received packet, or NULL
2795  * @v rc	Error code
2796  *
2797  * This logs the error with the wrapping net_device, and frees iob if
2798  * it is passed.
2799  */
net80211_rx_err(struct net80211_device * dev,struct io_buffer * iob,int rc)2800 void net80211_rx_err ( struct net80211_device *dev,
2801 		       struct io_buffer *iob, int rc )
2802 {
2803 	netdev_rx_err ( dev->netdev, iob, rc );
2804 }
2805 
2806 /** Indicate the completed transmission of a packet
2807  *
2808  * @v dev	802.11 device
2809  * @v iob	I/O buffer of transmitted packet
2810  * @v retries	Number of times this packet was retransmitted
2811  * @v rc	Error code, or 0 for success
2812  *
2813  * This logs an error with the wrapping net_device if one occurred,
2814  * and removes and frees the I/O buffer from its TX queue. The
2815  * provided retry information is used to tune our transmission rate.
2816  *
2817  * If the packet did not need to be retransmitted because it was
2818  * properly ACKed the first time, @a retries should be 0.
2819  */
net80211_tx_complete(struct net80211_device * dev,struct io_buffer * iob,int retries,int rc)2820 void net80211_tx_complete ( struct net80211_device *dev,
2821 			    struct io_buffer *iob, int retries, int rc )
2822 {
2823 	/* Update rate-control algorithm */
2824 	if ( dev->rctl )
2825 		rc80211_update_tx ( dev, retries, rc );
2826 
2827 	/* Pass completion onward */
2828 	netdev_tx_complete_err ( dev->netdev, iob, rc );
2829 }
2830