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1 #ifndef _GPXE_NET80211_H
2 #define _GPXE_NET80211_H
3 
4 #include <gpxe/process.h>
5 #include <gpxe/ieee80211.h>
6 #include <gpxe/iobuf.h>
7 #include <gpxe/netdevice.h>
8 #include <gpxe/rc80211.h>
9 
10 /** @file
11  *
12  * The gPXE 802.11 MAC layer.
13  */
14 
15 /*
16  * Major things NOT YET supported:
17  * - any type of security
18  * - 802.11n
19  *
20  * Major things that probably will NEVER be supported, barring a
21  * compelling use case and/or corporate sponsorship:
22  * - QoS
23  * - 802.1X authentication ("WPA Enterprise")
24  * - Contention-free periods
25  * - "ad-hoc" networks (IBSS), monitor mode, host AP mode
26  * - hidden networks on the 5GHz band due to regulatory issues
27  * - spectrum management on the 5GHz band (TPC and DFS), as required
28  *   in some non-US regulatory domains
29  * - Clause 14 PHYs (Frequency-Hopping Spread Spectrum on 2.4GHz)
30  *   and Clause 16 PHYs (infrared) - I'm not aware of any real-world
31  *   use of these.
32  */
33 
34 FILE_LICENCE ( GPL2_OR_LATER );
35 
36 /* All 802.11 devices are handled using a generic "802.11 device"
37    net_device, with a link in its `priv' field to a net80211_device
38    which we use to handle 802.11-specific details. */
39 
40 
41 /** @defgroup net80211_band RF bands on which an 802.11 device can transmit */
42 /** @{ */
43 
44 /** The 2.4 GHz ISM band, unlicensed in most countries */
45 #define NET80211_BAND_2GHZ	0
46 /** The band from 4.9 GHz to 5.7 GHz, which tends to be more restricted */
47 #define NET80211_BAND_5GHZ	1
48 /** Number of RF bands */
49 #define NET80211_NR_BANDS	2
50 
51 /** Bitmask for the 2GHz band */
52 #define NET80211_BAND_BIT_2GHZ	(1 << 0)
53 /** Bitmask for the 5GHz band */
54 #define NET80211_BAND_BIT_5GHZ	(1 << 1)
55 
56 /** @} */
57 
58 
59 /** @defgroup net80211_mode 802.11 operation modes supported by hardware */
60 /** @{ */
61 
62 /** 802.11a: 54 Mbps operation using OFDM signaling on the 5GHz band */
63 #define NET80211_MODE_A		(1 << 0)
64 
65 /** 802.11b: 1-11 Mbps operation using DSSS/CCK signaling on the 2.4GHz band */
66 #define NET80211_MODE_B		(1 << 1)
67 
68 /** 802.11g: 54 Mbps operation using ERP/OFDM signaling on the 2.4GHz band */
69 #define NET80211_MODE_G		(1 << 2)
70 
71 /** 802.11n: High-rate operation using MIMO technology on 2.4GHz or 5GHz */
72 #define NET80211_MODE_N		(1 << 3)
73 
74 /** @} */
75 
76 
77 /** @defgroup net80211_cfg Constants for the net80211 config callback */
78 /** @{ */
79 
80 /** Channel choice (@c dev->channel) or regulatory parameters have changed */
81 #define NET80211_CFG_CHANNEL	(1 << 0)
82 
83 /** Requested transmission rate (@c dev->rate) has changed */
84 #define NET80211_CFG_RATE	(1 << 1)
85 
86 /** Association has been established with a new BSS (@c dev->bssid) */
87 #define NET80211_CFG_ASSOC	(1 << 2)
88 
89 /** Low-level link parameters (short preamble, protection, etc) have changed */
90 #define NET80211_CFG_PHY_PARAMS	(1 << 3)
91 
92 /** @} */
93 
94 
95 /** An 802.11 security handshaking protocol */
96 enum net80211_security_proto {
97 	/** No security handshaking
98 	 *
99 	 * This might be used with an open network or with WEP, as
100 	 * WEP does not have a cryptographic handshaking phase.
101 	 */
102 	NET80211_SECPROT_NONE = 0,
103 
104 	/** Pre-shared key handshaking
105 	 *
106 	 * This implements the "WPA Personal" handshake. 802.1X
107 	 * authentication is not performed -- the user supplies a
108 	 * pre-shared key directly -- but there is a 4-way handshake
109 	 * between client and AP to verify that both have the same key
110 	 * without revealing the contents of that key.
111 	 */
112 	NET80211_SECPROT_PSK = 1,
113 
114 	/** Full EAP 802.1X handshaking
115 	 *
116 	 * This implements the "WPA Enterprise" handshake, connecting
117 	 * to an 802.1X authentication server to provide credentials
118 	 * and receive a pairwise master key (PMK), which is then used
119 	 * in the same 4-way handshake as the PSK method.
120 	 */
121 	NET80211_SECPROT_EAP = 2,
122 
123 	/** Dummy value used when the handshaking type can't be detected */
124 	NET80211_SECPROT_UNKNOWN = 3,
125 };
126 
127 
128 /** An 802.11 data encryption algorithm */
129 enum net80211_crypto_alg {
130 	/** No security, an "Open" network */
131 	NET80211_CRYPT_NONE = 0,
132 
133 	/** Network protected with WEP (awful RC4-based system)
134 	 *
135 	 * WEP uses a naive application of RC4, with a monotonically
136 	 * increasing initialization vector that is prepended to the
137 	 * key to initialize the RC4 keystream. It is highly insecure
138 	 * and can be completely cracked or subverted using automated,
139 	 * robust, freely available tools (aircrack-ng) in minutes.
140 	 *
141 	 * 40-bit and 104-bit WEP are differentiated only by the size
142 	 * of the key. They may be advertised as 64-bit and 128-bit,
143 	 * counting the non-random IV as part of the key bits.
144 	 */
145 	NET80211_CRYPT_WEP = 1,
146 
147 	/** Network protected with TKIP (better RC4-based system)
148 	 *
149 	 * Usually known by its trade name of WPA (Wi-Fi Protected
150 	 * Access), TKIP implements a message integrity code (MIC)
151 	 * called Michael, a timestamp counter for replay prevention,
152 	 * and a key mixing function that together remove almost all
153 	 * the security problems with WEP. Countermeasures are
154 	 * implemented to prevent high data-rate attacks.
155 	 *
156 	 * There exists one known attack on TKIP, that allows one to
157 	 * send between 7 and 15 arbitrary short data packets on a
158 	 * QoS-enabled network given about an hour of data
159 	 * gathering. Since gPXE does not support QoS for 802.11
160 	 * networks, this is not a threat to us. The only other method
161 	 * is a brute-force passphrase attack.
162 	 */
163 	NET80211_CRYPT_TKIP = 2,
164 
165 	/** Network protected with CCMP (AES-based system)
166 	 *
167 	 * Often called WPA2 in commerce, or RSNA (Robust Security
168 	 * Network Architecture) in the 802.11 standard, CCMP is
169 	 * highly secure and does not have any known attack vectors.
170 	 * Since it is based on a block cipher, the statistical
171 	 * correlation and "chopchop" attacks used with great success
172 	 * against WEP and minor success against TKIP fail.
173 	 */
174 	NET80211_CRYPT_CCMP = 3,
175 
176 	/** Dummy value used when the cryptosystem can't be detected */
177 	NET80211_CRYPT_UNKNOWN = 4,
178 };
179 
180 
181 /** @defgroup net80211_state Bits for the 802.11 association state field */
182 /** @{ */
183 
184 /** An error code indicating the failure mode, or 0 if successful */
185 #define NET80211_STATUS_MASK    0x7F
186 
187 /** Whether the error code provided is a "reason" code, not a "status" code */
188 #define NET80211_IS_REASON	0x80
189 
190 /** Whether we have found the network we will be associating with */
191 #define NET80211_PROBED		(1 << 8)
192 
193 /** Whether we have successfully authenticated with the network
194  *
195  * This usually has nothing to do with actual security; it is a
196  * holdover from older 802.11 implementation ideas.
197  */
198 #define NET80211_AUTHENTICATED  (1 << 9)
199 
200 /** Whether we have successfully associated with the network */
201 #define NET80211_ASSOCIATED     (1 << 10)
202 
203 /** Whether we have completed security handshaking with the network
204  *
205  * Once this is set, we can send data packets. For that reason this
206  * bit is set even in cases where no security handshaking is
207  * required.
208  */
209 #define NET80211_CRYPTO_SYNCED  (1 << 11)
210 
211 /** Whether the auto-association task is running */
212 #define NET80211_WORKING        (1 << 12)
213 
214 /** Whether the auto-association task is waiting for a reply from the AP */
215 #define NET80211_WAITING        (1 << 13)
216 
217 /** Whether the auto-association task should be suppressed
218  *
219  * This is set by the `iwlist' command so that it can open the device
220  * without starting another probe process that will interfere with its
221  * own.
222  */
223 #define NET80211_NO_ASSOC	(1 << 14)
224 
225 /** Whether this association was performed using a broadcast SSID
226  *
227  * If the user opened this device without netX/ssid set, the device's
228  * SSID will be set to that of the network it chooses to associate
229  * with, but the netX/ssid setting will remain blank. If we don't
230  * remember that we started from no specified SSID, it will appear
231  * every time settings are updated (e.g. after DHCP) that we need to
232  * reassociate due to the difference between the set SSID and our own.
233  */
234 #define NET80211_AUTO_SSID	(1 << 15)
235 
236 
237 /** @} */
238 
239 
240 /** @defgroup net80211_phy 802.11 physical layer flags */
241 /** @{ */
242 
243 /** Whether to use RTS/CTS or CTS-to-self protection for transmissions
244  *
245  * Since the RTS or CTS is transmitted using 802.11b signaling, and
246  * includes a field indicating the amount of time that will be used by
247  * transmission of the following packet, this serves as an effective
248  * protection mechanism to avoid 802.11b clients interfering with
249  * 802.11g clients on mixed networks.
250  */
251 #define NET80211_PHY_USE_PROTECTION      (1 << 1)
252 
253 /** Whether to use 802.11b short preamble operation
254  *
255  * Short-preamble operation can moderately increase throughput on
256  * 802.11b networks operating between 2Mbps and 11Mbps. It is
257  * irrelevant for 802.11g data rates, since they use a different
258  * modulation scheme.
259  */
260 #define NET80211_PHY_USE_SHORT_PREAMBLE  (1 << 2)
261 
262 /** Whether to use 802.11g short slot operation
263  *
264  * This affects a low-level timing parameter of 802.11g transmissions.
265  */
266 #define NET80211_PHY_USE_SHORT_SLOT      (1 << 3)
267 
268 /** @} */
269 
270 
271 /** The maximum number of TX rates we allow to be configured simultaneously */
272 #define NET80211_MAX_RATES	16
273 
274 /** The maximum number of channels we allow to be configured simultaneously */
275 #define NET80211_MAX_CHANNELS	32
276 
277 /** Seconds we'll wait to get all fragments of a packet */
278 #define NET80211_FRAG_TIMEOUT	2
279 
280 /** The number of fragments we can receive at once
281  *
282  * The 802.11 standard requires that this be at least 3.
283  */
284 #define NET80211_NR_CONCURRENT_FRAGS 3
285 
286 /** Maximum TX power to allow (dBm), if we don't get a regulatory hint */
287 #define NET80211_REG_TXPOWER	20
288 
289 
290 struct net80211_device;
291 
292 /** Operations that must be implemented by an 802.11 driver */
293 struct net80211_device_operations {
294 	/** Open 802.11 device
295 	 *
296 	 * @v dev	802.11 device
297 	 * @ret rc	Return status code
298 	 *
299 	 * This method should allocate RX I/O buffers and enable the
300 	 * hardware to start transmitting and receiving packets on the
301 	 * channels its net80211_register() call indicated it could
302 	 * handle. It does not need to tune the antenna to receive
303 	 * packets on any particular channel.
304 	 */
305 	int ( * open ) ( struct net80211_device *dev );
306 
307 	/** Close 802.11 network device
308 	 *
309 	 * @v dev	802.11 device
310 	 *
311 	 * This method should stop the flow of packets, and call
312 	 * net80211_tx_complete() for any packets remaining in the
313 	 * device's TX queue.
314 	 */
315 	void ( * close ) ( struct net80211_device *dev );
316 
317 	/** Transmit packet on 802.11 network device
318 	 *
319 	 * @v dev	802.11 device
320 	 * @v iobuf	I/O buffer
321 	 * @ret rc	Return status code
322 	 *
323 	 * This method should cause the hardware to initiate
324 	 * transmission of the I/O buffer, using the channel and rate
325 	 * most recently indicated by an appropriate call to the
326 	 * @c config callback. The 802.11 layer guarantees that said
327 	 * channel and rate will be the same as those currently
328 	 * reflected in the fields of @a dev.
329 	 *
330 	 * If this method returns success, the I/O buffer remains
331 	 * owned by the network layer's TX queue, and the driver must
332 	 * eventually call net80211_tx_complete() to free the buffer
333 	 * whether transmission succeeded or not. If this method
334 	 * returns failure, it will be interpreted as "failure to
335 	 * enqueue buffer" and the I/O buffer will be immediately
336 	 * released.
337 	 *
338 	 * This method is guaranteed to be called only when the device
339 	 * is open.
340 	 */
341 	int ( * transmit ) ( struct net80211_device *dev,
342 			     struct io_buffer *iobuf );
343 
344 	/** Poll for completed and received packets
345 	 *
346 	 * @v dev	802.11 device
347 	 *
348 	 * This method should cause the hardware to check for
349 	 * completed transmissions and received packets. Any received
350 	 * packets should be delivered via net80211_rx(), and
351 	 * completed transmissions should be indicated using
352 	 * net80211_tx_complete().
353 	 *
354 	 * This method is guaranteed to be called only when the device
355 	 * is open.
356 	 */
357 	void ( * poll ) ( struct net80211_device *dev );
358 
359 	/** Enable or disable interrupts
360 	 *
361 	 * @v dev	802.11 device
362 	 * @v enable	If TRUE, interrupts should be enabled
363 	 */
364 	void ( * irq ) ( struct net80211_device *dev, int enable );
365 
366 	/** Update hardware state to match 802.11 layer state
367 	 *
368 	 * @v dev	802.11 device
369 	 * @v changed	Set of flags indicating what may have changed
370 	 * @ret rc	Return status code
371 	 *
372 	 * This method should cause the hardware state to be
373 	 * reinitialized from the state indicated in fields of
374 	 * net80211_device, in the areas indicated by bits set in
375 	 * @a changed. If the hardware is unable to do so, this method
376 	 * may return an appropriate error indication.
377 	 *
378 	 * This method is guaranteed to be called only when the device
379 	 * is open.
380 	 */
381 	int ( * config ) ( struct net80211_device *dev, int changed );
382 };
383 
384 /** An 802.11 RF channel. */
385 struct net80211_channel
386 {
387 	/** The band with which this channel is associated */
388 	u8 band;
389 
390 	/** A channel number interpreted according to the band
391 	 *
392 	 * The 2.4GHz band uses channel numbers from 1-13 at 5MHz
393 	 * intervals such that channel 1 is 2407 MHz; channel 14,
394 	 * legal for use only in Japan, is defined separately as 2484
395 	 * MHz. Adjacent channels will overlap, since 802.11
396 	 * transmissions use a 20 MHz (4-channel) bandwidth. Most
397 	 * commonly, channels 1, 6, and 11 are used.
398 	 *
399 	 * The 5GHz band uses channel numbers derived directly from
400 	 * the frequency; channel 0 is 5000 MHz, and channels are
401 	 * always spaced 5 MHz apart. Channel numbers over 180 are
402 	 * relative to 4GHz instead of 5GHz, but these are rarely
403 	 * seen. Most channels are not legal for use.
404 	 */
405 	u8 channel_nr;
406 
407 	/** The center frequency for this channel
408 	 *
409 	 * Currently a bandwidth of 20 MHz is assumed.
410 	 */
411 	u16 center_freq;
412 
413 	/** Hardware channel value */
414 	u16 hw_value;
415 
416 	/** Maximum allowable transmit power, in dBm
417 	 *
418 	 * This should be interpreted as EIRP, the power supplied to
419 	 * an ideal isotropic antenna in order to achieve the same
420 	 * average signal intensity as the real hardware at a
421 	 * particular distance.
422 	 *
423 	 * Currently no provision is made for directional antennas.
424 	 */
425 	u8 maxpower;
426 };
427 
428 /** Information on the capabilities of an 802.11 hardware device
429  *
430  * In its probe callback, an 802.11 driver must read hardware
431  * registers to determine the appropriate contents of this structure,
432  * fill it, and pass it to net80211_register() so that the 802.11
433  * layer knows how to treat the hardware and what to advertise as
434  * supported to access points.
435  */
436 struct net80211_hw_info
437 {
438 	/** Default hardware MAC address.
439 	 *
440 	 * The user may change this by setting the @c netX/mac setting
441 	 * before the driver's open function is called; in that case
442 	 * the driver must set the hardware MAC address to the address
443 	 * contained in the wrapping net_device's ll_addr field, or if
444 	 * that is impossible, set that ll_addr field back to the
445 	 * unchangeable hardware MAC address.
446 	 */
447 	u8 hwaddr[ETH_ALEN];
448 
449 	/** A bitwise OR of the 802.11x modes supported by this device */
450 	int modes;
451 
452 	/** A bitwise OR of the bands on which this device can communicate */
453 	int bands;
454 
455 	/** A set of flags indicating peculiarities of this device. */
456 	enum {
457 		/** Received frames include a frame check sequence. */
458 		NET80211_HW_RX_HAS_FCS = (1 << 1),
459 
460 		/** Hardware doesn't support 2.4GHz short preambles
461 		 *
462 		 * This is only relevant for 802.11b operation above
463 		 * 2Mbps. All 802.11g devices support short preambles.
464 		 */
465 		NET80211_HW_NO_SHORT_PREAMBLE = (1 << 2),
466 
467 		/** Hardware doesn't support 802.11g short slot operation */
468 		NET80211_HW_NO_SHORT_SLOT = (1 << 3),
469 	} flags;
470 
471 	/** Signal strength information that can be provided by the device
472 	 *
473 	 * Signal strength is passed to net80211_rx(), primarily to
474 	 * allow determination of the closest access point for a
475 	 * multi-AP network. The units are provided for completeness
476 	 * of status displays.
477 	 */
478 	enum {
479 		/** No signal strength information supported */
480 		NET80211_SIGNAL_NONE = 0,
481 		/** Signal strength in arbitrary units */
482 		NET80211_SIGNAL_ARBITRARY,
483 		/** Signal strength in decibels relative to arbitrary base */
484 		NET80211_SIGNAL_DB,
485 		/** Signal strength in decibels relative to 1mW */
486 		NET80211_SIGNAL_DBM,
487 	} signal_type;
488 
489 	/** Maximum signal in arbitrary cases
490 	 *
491 	 * If signal_type is NET80211_SIGNAL_ARBITRARY or
492 	 * NET80211_SIGNAL_DB, the driver should report it on a scale
493 	 * from 0 to signal_max.
494 	 */
495 	unsigned signal_max;
496 
497 	/** List of RF channels supported by the card */
498 	struct net80211_channel channels[NET80211_MAX_CHANNELS];
499 
500 	/** Number of supported channels */
501 	int nr_channels;
502 
503 	/** List of transmission rates supported by the card, indexed by band
504 	 *
505 	 * Rates should be in 100kbps increments (e.g. 11 Mbps would
506 	 * be represented as the number 110).
507 	 */
508 	u16 rates[NET80211_NR_BANDS][NET80211_MAX_RATES];
509 
510 	/** Number of supported rates, indexed by band */
511 	int nr_rates[NET80211_NR_BANDS];
512 
513 	/** Estimate of the time required to change channels, in microseconds
514 	 *
515 	 * If this is not known, a guess on the order of a few
516 	 * milliseconds (value of 1000-5000) is reasonable.
517 	 */
518 	unsigned channel_change_time;
519 };
520 
521 /** Structure tracking received fragments for a packet
522  *
523  * We set up a fragment cache entry when we receive a packet marked as
524  * fragment 0 with the "more fragments" bit set in its frame control
525  * header. We are required by the 802.11 standard to track 3
526  * fragmented packets arriving simultaneously; if we receive more we
527  * may drop some. Upon receipt of a new fragment-0 packet, if no entry
528  * is available or expired, we take over the most @e recent entry for
529  * the new packet, since we don't want to starve old entries from ever
530  * finishing at all. If we get a fragment after the zeroth with no
531  * cache entry for its packet, we drop it.
532  */
533 struct net80211_frag_cache
534 {
535 	/** Whether this cache entry is in use */
536 	u8 in_use;
537 
538 	/** Sequence number of this MSDU (packet) */
539 	u16 seqnr;
540 
541 	/** Timestamp from point at which first fragment was collected */
542 	u32 start_ticks;
543 
544 	/** Buffers for each fragment */
545 	struct io_buffer *iob[16];
546 };
547 
548 
549 /** Interface to an 802.11 security handshaking protocol
550  *
551  * Security handshaking protocols handle parsing a user-specified key
552  * into a suitable input to the encryption algorithm, and for WPA and
553  * better systems, manage performing whatever authentication with the
554  * network is necessary.
555  *
556  * At all times when any method in this structure is called with a
557  * net80211_device argument @a dev, a dynamically allocated copy of
558  * the handshaker structure itself with space for the requested amount
559  * of private data may be accessed as @c dev->handshaker. The
560  * structure will not be modified, and will only be freed during
561  * reassociation and device closing after the @a stop method has been
562  * called.
563  */
564 struct net80211_handshaker
565 {
566 	/** The security handshaking protocol implemented */
567 	enum net80211_security_proto protocol;
568 
569 	/** Initialize security handshaking protocol
570 	 *
571 	 * @v dev	802.11 device
572 	 * @ret rc	Return status code
573 	 *
574 	 * This method is expected to access @c netX/key or other
575 	 * applicable settings to determine the parameters for
576 	 * handshaking. If no handshaking is required, it should call
577 	 * sec80211_install() with the cryptosystem and key that are
578 	 * to be used, and @c start and @c step should be set to @c
579 	 * NULL.
580 	 *
581 	 * This is always called just before association is performed,
582 	 * but after its parameters have been set; in particular, you
583 	 * may rely on the contents of the @a essid field in @a dev.
584 	 */
585 	int ( * init ) ( struct net80211_device *dev );
586 
587 	/** Start handshaking
588 	 *
589 	 * @v dev	802.11 device
590 	 * @ret rc	Return status code
591 	 *
592 	 * This method is expected to set up internal state so that
593 	 * packets sent immediately after association, before @a step
594 	 * can be called, will be handled appropriately.
595 	 *
596 	 * This is always called just before association is attempted.
597 	 */
598 	int ( * start ) ( struct net80211_device *dev );
599 
600 	/** Process handshaking state
601 	 *
602 	 * @v dev	802.11 device
603 	 * @ret rc	Return status code, or positive if done
604 	 *
605 	 * This method is expected to perform as much progress on the
606 	 * protocol it implements as is possible without blocking. It
607 	 * should return 0 if it wishes to be called again, a negative
608 	 * return status code on error, or a positive value if
609 	 * handshaking is complete. In the case of a positive return,
610 	 * net80211_crypto_install() must have been called.
611 	 *
612 	 * If handshaking may require further action (e.g. an AP that
613 	 * might decide to rekey), handlers must be installed by this
614 	 * function that will act without further calls to @a step.
615 	 */
616 	int ( * step ) ( struct net80211_device *dev );
617 
618 	/** Change cryptographic key based on setting
619 	 *
620 	 * @v dev	802.11 device
621 	 * @ret rc	Return status code
622 	 *
623 	 * This method is called whenever the @c netX/key setting
624 	 * @e may have been changed. It is expected to determine
625 	 * whether it did in fact change, and if so, to install the
626 	 * new key using net80211_crypto_install(). If it is not
627 	 * possible to do this immediately, this method should return
628 	 * an error; in that case the 802.11 stack will reassociate,
629 	 * following the usual init/start/step sequence.
630 	 *
631 	 * This method is only relevant when it is possible to
632 	 * associate successfully with an incorrect key. When it is
633 	 * not, a failed association will be retried until the user
634 	 * changes the key setting, and a successful association will
635 	 * not be dropped due to such a change. When association with
636 	 * an incorrect key is impossible, this function should return
637 	 * 0 after performing no action.
638 	 */
639 	int ( * change_key ) ( struct net80211_device *dev );
640 
641 	/** Stop security handshaking handlers
642 	 *
643 	 * @v dev	802.11 device
644 	 *
645 	 * This method is called just before freeing a security
646 	 * handshaker; it could, for example, delete a process that @a
647 	 * start had created to manage the security of the connection.
648 	 * If not needed it may be set to NULL.
649 	 */
650 	void ( * stop ) ( struct net80211_device *dev );
651 
652 	/** Amount of private data requested
653 	 *
654 	 * Before @c init is called for the first time, this structure's
655 	 * @c priv pointer will point to this many bytes of allocated
656 	 * data, where the allocation will be performed separately for
657 	 * each net80211_device.
658 	 */
659 	int priv_len;
660 
661 	/** Whether @a start has been called
662 	 *
663 	 * Reset to 0 after @a stop is called.
664 	 */
665 	int started;
666 
667 	/** Pointer to private data
668 	 *
669 	 * In initializing this structure statically for a linker
670 	 * table, set this to NULL.
671 	 */
672 	void *priv;
673 };
674 
675 #define NET80211_HANDSHAKERS __table ( struct net80211_handshaker, \
676 				       "net80211_handshakers" )
677 #define __net80211_handshaker __table_entry ( NET80211_HANDSHAKERS, 01 )
678 
679 
680 /** Interface to an 802.11 cryptosystem
681  *
682  * Cryptosystems define a net80211_crypto structure statically, using
683  * a gPXE linker table to make it available to the 802.11 layer. When
684  * the cryptosystem needs to be used, the 802.11 code will allocate a
685  * copy of the static definition plus whatever space the algorithm has
686  * requested for private state, and point net80211_device::crypto or
687  * net80211_device::gcrypto at it.
688  */
689 struct net80211_crypto
690 {
691 	/** The cryptographic algorithm implemented */
692 	enum net80211_crypto_alg algorithm;
693 
694 	/** Initialize cryptosystem using a given key
695 	 *
696 	 * @v crypto	802.11 cryptosystem
697 	 * @v key	Pointer to key bytes
698 	 * @v keylen	Number of key bytes
699 	 * @v rsc	Initial receive sequence counter, if applicable
700 	 * @ret rc	Return status code
701 	 *
702 	 * This method is passed the communication key provided by the
703 	 * security handshake handler, which will already be in the
704 	 * low-level form required. It may not store a pointer to the
705 	 * key after returning; it must copy it to its private storage.
706 	 */
707 	int ( * init ) ( struct net80211_crypto *crypto, const void *key,
708 			 int keylen, const void *rsc );
709 
710 	/** Encrypt a frame using the cryptosystem
711 	 *
712 	 * @v crypto	802.11 cryptosystem
713 	 * @v iob	I/O buffer
714 	 * @ret eiob	Newly allocated I/O buffer with encrypted packet
715 	 *
716 	 * This method is called to encrypt a single frame. It is
717 	 * guaranteed that initialize() will have completed
718 	 * successfully before this method is called.
719 	 *
720 	 * The frame passed already has an 802.11 header prepended,
721 	 * but the PROTECTED bit in the frame control field will not
722 	 * be set; this method is responsible for setting it. The
723 	 * returned I/O buffer should contain a complete copy of @a
724 	 * iob, including the 802.11 header, but with the PROTECTED
725 	 * bit set, the data encrypted, and whatever encryption
726 	 * headers/trailers are necessary added.
727 	 *
728 	 * This method should never free the passed I/O buffer.
729 	 *
730 	 * Return NULL if the packet could not be encrypted, due to
731 	 * memory limitations or otherwise.
732 	 */
733 	struct io_buffer * ( * encrypt ) ( struct net80211_crypto *crypto,
734 					   struct io_buffer *iob );
735 
736 	/** Decrypt a frame using the cryptosystem
737 	 *
738 	 * @v crypto	802.11 cryptosystem
739 	 * @v eiob	Encrypted I/O buffer
740 	 * @ret iob	Newly allocated I/O buffer with decrypted packet
741 	 *
742 	 * This method is called to decrypt a single frame. It is
743 	 * guaranteed that initialize() will have completed
744 	 * successfully before this method is called.
745 	 *
746 	 * Decryption follows the reverse of the pattern used for
747 	 * encryption: this method must copy the 802.11 header into
748 	 * the returned packet, decrypt the data stream, remove any
749 	 * encryption header or trailer, and clear the PROTECTED bit
750 	 * in the frame control header.
751 	 *
752 	 * This method should never free the passed I/O buffer.
753 	 *
754 	 * Return NULL if memory was not available for decryption, if
755 	 * a consistency or integrity check on the decrypted frame
756 	 * failed, or if the decrypted frame should not be processed
757 	 * by the network stack for any other reason.
758 	 */
759 	struct io_buffer * ( * decrypt ) ( struct net80211_crypto *crypto,
760 					   struct io_buffer *iob );
761 
762 	/** Length of private data requested to be allocated */
763 	int priv_len;
764 
765 	/** Private data for the algorithm to store key and state info */
766 	void *priv;
767 };
768 
769 #define NET80211_CRYPTOS __table ( struct net80211_crypto, "net80211_cryptos" )
770 #define __net80211_crypto __table_entry ( NET80211_CRYPTOS, 01 )
771 
772 
773 struct net80211_probe_ctx;
774 struct net80211_assoc_ctx;
775 
776 
777 /** Structure encapsulating the complete state of an 802.11 device
778  *
779  * An 802.11 device is always wrapped by a network device, and this
780  * network device is always pointed to by the @a netdev field. In
781  * general, operations should never be performed by 802.11 code using
782  * netdev functions directly. It is usually the case that the 802.11
783  * layer might need to do some processing or bookkeeping on top of
784  * what the netdevice code will do.
785  */
786 struct net80211_device
787 {
788 	/** The net_device that wraps us. */
789 	struct net_device *netdev;
790 
791 	/** List of 802.11 devices. */
792 	struct list_head list;
793 
794 	/** 802.11 device operations */
795 	struct net80211_device_operations *op;
796 
797 	/** Driver private data */
798 	void *priv;
799 
800 	/** Information about the hardware, provided to net80211_register() */
801 	struct net80211_hw_info *hw;
802 
803 	/* ---------- Channel and rate fields ---------- */
804 
805 	/** A list of all possible channels we might use */
806 	struct net80211_channel channels[NET80211_MAX_CHANNELS];
807 
808 	/** The number of channels in the channels array */
809 	u8 nr_channels;
810 
811 	/** The channel currently in use, as an index into the channels array */
812 	u8 channel;
813 
814 	/** A list of all possible TX rates we might use
815 	 *
816 	 * Rates are in units of 100 kbps.
817 	 */
818 	u16 rates[NET80211_MAX_RATES];
819 
820 	/** The number of transmission rates in the rates array */
821 	u8 nr_rates;
822 
823 	/** The rate currently in use, as an index into the rates array */
824 	u8 rate;
825 
826 	/** The rate to use for RTS/CTS transmissions
827 	 *
828 	 * This is always the fastest basic rate that is not faster
829 	 * than the data rate in use. Also an index into the rates array.
830 	 */
831 	u8 rtscts_rate;
832 
833 	/** Bitmask of basic rates
834 	 *
835 	 * If bit N is set in this value, with the LSB considered to
836 	 * be bit 0, then rate N in the rates array is a "basic" rate.
837 	 *
838 	 * We don't decide which rates are "basic"; our AP does, and
839 	 * we respect its wishes. We need to be able to identify basic
840 	 * rates in order to calculate the duration of a CTS packet
841 	 * used for 802.11 g/b interoperability.
842 	 */
843 	u32 basic_rates;
844 
845 	/* ---------- Association fields ---------- */
846 
847 	/** The asynchronous association process.
848 	 *
849 	 * When an 802.11 netdev is opened, or when the user changes
850 	 * the SSID setting on an open 802.11 device, an
851 	 * autoassociation task is started by net80211_autoassocate()
852 	 * to associate with the new best network. The association is
853 	 * asynchronous, but no packets can be transmitted until it is
854 	 * complete. If it is successful, the wrapping net_device is
855 	 * set as "link up". If it fails, @c assoc_rc will be set with
856 	 * an error indication.
857 	 */
858 	struct process proc_assoc;
859 
860 	/** Network with which we are associating
861 	 *
862 	 * This will be NULL when we are not actively in the process
863 	 * of associating with a network we have already successfully
864 	 * probed for.
865 	 */
866 	struct net80211_wlan *associating;
867 
868 	/** Context for the association process
869 	 *
870 	 * This is a probe_ctx if the @c PROBED flag is not set in @c
871 	 * state, and an assoc_ctx otherwise.
872 	 */
873 	union {
874 		struct net80211_probe_ctx *probe;
875 		struct net80211_assoc_ctx *assoc;
876 	} ctx;
877 
878 	/** Security handshaker being used */
879 	struct net80211_handshaker *handshaker;
880 
881 	/** State of our association to the network
882 	 *
883 	 * Since the association process happens asynchronously, it's
884 	 * necessary to have some channel of communication so the
885 	 * driver can say "I got an association reply and we're OK" or
886 	 * similar. This variable provides that link. It is a bitmask
887 	 * of any of NET80211_PROBED, NET80211_AUTHENTICATED,
888 	 * NET80211_ASSOCIATED, NET80211_CRYPTO_SYNCED to indicate how
889 	 * far along in associating we are; NET80211_WORKING if the
890 	 * association task is running; and NET80211_WAITING if a
891 	 * packet has been sent that we're waiting for a reply to. We
892 	 * can only be crypto-synced if we're associated, we can
893 	 * only be associated if we're authenticated, we can only be
894 	 * authenticated if we've probed.
895 	 *
896 	 * If an association process fails (that is, we receive a
897 	 * packet with an error indication), the error code is copied
898 	 * into bits 6-0 of this variable and bit 7 is set to specify
899 	 * what type of error code it is. An AP can provide either a
900 	 * "status code" (0-51 are defined) explaining why it refused
901 	 * an association immediately, or a "reason code" (0-45 are
902 	 * defined) explaining why it canceled an association after it
903 	 * had originally OK'ed it. Status and reason codes serve
904 	 * similar functions, but they use separate error message
905 	 * tables. A gPXE-formatted return status code (negative) is
906 	 * placed in @c assoc_rc.
907 	 *
908 	 * If the failure to associate is indicated by a status code,
909 	 * the NET80211_IS_REASON bit will be clear; if it is
910 	 * indicated by a reason code, the bit will be set. If we were
911 	 * successful, both zero status and zero reason mean success,
912 	 * so there is no ambiguity.
913 	 *
914 	 * To prevent association when opening the device, user code
915 	 * can set the NET80211_NO_ASSOC bit. The final bit in this
916 	 * variable, NET80211_AUTO_SSID, is used to remember whether
917 	 * we picked our SSID through automated probing as opposed to
918 	 * user specification; the distinction becomes relevant in the
919 	 * settings applicator.
920 	 */
921 	u16 state;
922 
923 	/** Return status code associated with @c state */
924 	int assoc_rc;
925 
926 	/** RSN or WPA information element to include with association
927 	 *
928 	 * If set to @c NULL, none will be included. It is expected
929 	 * that this will be set by the @a init function of a security
930 	 * handshaker if it is needed.
931 	 */
932 	union ieee80211_ie *rsn_ie;
933 
934 	/* ---------- Parameters of currently associated network ---------- */
935 
936 	/** 802.11 cryptosystem for our current network
937 	 *
938 	 * For an open network, this will be set to NULL.
939 	 */
940 	struct net80211_crypto *crypto;
941 
942 	/** 802.11 cryptosystem for multicast and broadcast frames
943 	 *
944 	 * If this is NULL, the cryptosystem used for receiving
945 	 * unicast frames will also be used for receiving multicast
946 	 * and broadcast frames. Transmitted multicast and broadcast
947 	 * frames are always sent unicast to the AP, who multicasts
948 	 * them on our behalf; thus they always use the unicast
949 	 * cryptosystem.
950 	 */
951 	struct net80211_crypto *gcrypto;
952 
953 	/** MAC address of the access point most recently associated */
954 	u8 bssid[ETH_ALEN];
955 
956 	/** SSID of the access point we are or will be associated with
957 	 *
958 	 * Although the SSID field in 802.11 packets is generally not
959 	 * NUL-terminated, here and in net80211_wlan we add a NUL for
960 	 * convenience.
961 	 */
962 	char essid[IEEE80211_MAX_SSID_LEN+1];
963 
964 	/** Association ID given to us by the AP */
965 	u16 aid;
966 
967 	/** TSFT value for last beacon received, microseconds */
968 	u64 last_beacon_timestamp;
969 
970 	/** Time between AP sending beacons, microseconds */
971 	u32 tx_beacon_interval;
972 
973 	/** Smoothed average time between beacons, microseconds */
974 	u32 rx_beacon_interval;
975 
976 	/* ---------- Physical layer information ---------- */
977 
978 	/** Physical layer options
979 	 *
980 	 * These control the use of CTS protection, short preambles,
981 	 * and short-slot operation.
982 	 */
983 	int phy_flags;
984 
985 	/** Signal strength of last received packet */
986 	int last_signal;
987 
988 	/** Rate control state */
989 	struct rc80211_ctx *rctl;
990 
991 	/* ---------- Packet handling state ---------- */
992 
993 	/** Fragment reassembly state */
994 	struct net80211_frag_cache frags[NET80211_NR_CONCURRENT_FRAGS];
995 
996 	/** The sequence number of the last packet we sent */
997 	u16 last_tx_seqnr;
998 
999 	/** Packet duplication elimination state
1000 	 *
1001 	 * We are only required to handle immediate duplicates for
1002 	 * each direct sender, and since we can only have one direct
1003 	 * sender (the AP), we need only keep the sequence control
1004 	 * field from the most recent packet we've received. Thus,
1005 	 * this field stores the last sequence control field we've
1006 	 * received for a packet from the AP.
1007 	 */
1008 	u16 last_rx_seq;
1009 
1010 	/** RX management packet queue
1011 	 *
1012 	 * Sometimes we want to keep probe, beacon, and action packets
1013 	 * that we receive, such as when we're scanning for networks.
1014 	 * Ordinarily we drop them because they are sent at a large
1015 	 * volume (ten beacons per second per AP, broadcast) and we
1016 	 * have no need of them except when we're scanning.
1017 	 *
1018 	 * When keep_mgmt is TRUE, received probe, beacon, and action
1019 	 * management packets will be stored in this queue.
1020 	 */
1021 	struct list_head mgmt_queue;
1022 
1023 	/** RX management packet info queue
1024 	 *
1025 	 * We need to keep track of the signal strength for management
1026 	 * packets we're keeping, because that provides the only way
1027 	 * to distinguish between multiple APs for the same network.
1028 	 * Since we can't extend io_buffer to store signal, this field
1029 	 * heads a linked list of "RX packet info" structures that
1030 	 * contain that signal strength field. Its entries always
1031 	 * parallel the entries in mgmt_queue, because the two queues
1032 	 * are always added to or removed from in parallel.
1033 	 */
1034 	struct list_head mgmt_info_queue;
1035 
1036 	/** Whether to store management packets
1037 	 *
1038 	 * Received beacon, probe, and action packets will be added to
1039 	 * mgmt_queue (and their signal strengths added to
1040 	 * mgmt_info_queue) only when this variable is TRUE. It should
1041 	 * be set by net80211_keep_mgmt() (which returns the old
1042 	 * value) only when calling code is prepared to poll the
1043 	 * management queue frequently, because packets will otherwise
1044 	 * pile up and exhaust memory.
1045 	 */
1046 	int keep_mgmt;
1047 };
1048 
1049 /** Structure representing a probed network.
1050  *
1051  * This is returned from the net80211_probe_finish functions and
1052  * passed to the low-level association functions. At least essid,
1053  * bssid, channel, beacon, and security must be filled in if you want
1054  * to build this structure manually.
1055  */
1056 struct net80211_wlan
1057 {
1058 	/** The human-readable ESSID (network name)
1059 	 *
1060 	 * Although the 802.11 SSID field is generally not
1061 	 * NUL-terminated, the gPXE code adds an extra NUL (and
1062 	 * expects one in this structure) for convenience.
1063 	 */
1064 	char essid[IEEE80211_MAX_SSID_LEN+1];
1065 
1066 	/** MAC address of the strongest-signal access point for this ESSID */
1067 	u8 bssid[ETH_ALEN];
1068 
1069 	/** Signal strength of beacon frame from that access point */
1070 	int signal;
1071 
1072 	/** The channel on which that access point communicates
1073 	 *
1074 	 * This is a raw channel number (net80211_channel::channel_nr),
1075 	 * so that it will not be affected by reconfiguration of the
1076 	 * device channels array.
1077 	 */
1078 	int channel;
1079 
1080 	/** The complete beacon or probe-response frame received */
1081 	struct io_buffer *beacon;
1082 
1083 	/** Security handshaking method used on the network */
1084 	enum net80211_security_proto handshaking;
1085 
1086 	/** Cryptographic algorithm used on the network */
1087 	enum net80211_crypto_alg crypto;
1088 
1089 	/** Link to allow chaining multiple structures into a list to
1090 	    be returned from net80211_probe_finish_all(). */
1091 	struct list_head list;
1092 };
1093 
1094 
1095 /** 802.11 encryption key setting */
1096 extern struct setting net80211_key_setting __setting;
1097 
1098 
1099 /**
1100  * @defgroup net80211_probe 802.11 network location API
1101  * @{
1102  */
1103 int net80211_prepare_probe ( struct net80211_device *dev, int band,
1104 			     int active );
1105 struct net80211_probe_ctx * net80211_probe_start ( struct net80211_device *dev,
1106 						   const char *essid,
1107 						   int active );
1108 int net80211_probe_step ( struct net80211_probe_ctx *ctx );
1109 struct net80211_wlan *
1110 net80211_probe_finish_best ( struct net80211_probe_ctx *ctx );
1111 struct list_head *net80211_probe_finish_all ( struct net80211_probe_ctx *ctx );
1112 
1113 void net80211_free_wlan ( struct net80211_wlan *wlan );
1114 void net80211_free_wlanlist ( struct list_head *list );
1115 /** @} */
1116 
1117 
1118 /**
1119  * @defgroup net80211_mgmt 802.11 network management API
1120  * @{
1121  */
1122 struct net80211_device * net80211_get ( struct net_device *netdev );
1123 void net80211_autoassociate ( struct net80211_device *dev );
1124 
1125 int net80211_change_channel ( struct net80211_device *dev, int channel );
1126 void net80211_set_rate_idx ( struct net80211_device *dev, int rate );
1127 
1128 int net80211_keep_mgmt ( struct net80211_device *dev, int enable );
1129 struct io_buffer * net80211_mgmt_dequeue ( struct net80211_device *dev,
1130 					   int *signal );
1131 int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc,
1132 		       u8 bssid[ETH_ALEN], struct io_buffer *iob );
1133 /** @} */
1134 
1135 
1136 /**
1137  * @defgroup net80211_assoc 802.11 network association API
1138  * @{
1139  */
1140 int net80211_prepare_assoc ( struct net80211_device *dev,
1141 			     struct net80211_wlan *wlan );
1142 int net80211_send_auth ( struct net80211_device *dev,
1143 			 struct net80211_wlan *wlan, int method );
1144 int net80211_send_assoc ( struct net80211_device *dev,
1145 			  struct net80211_wlan *wlan );
1146 void net80211_deauthenticate ( struct net80211_device *dev, int rc );
1147 /** @} */
1148 
1149 
1150 /**
1151  * @defgroup net80211_driver 802.11 driver interface API
1152  * @{
1153  */
1154 struct net80211_device *net80211_alloc ( size_t priv_size );
1155 int net80211_register ( struct net80211_device *dev,
1156 			struct net80211_device_operations *ops,
1157 			struct net80211_hw_info *hw );
1158 u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate );
1159 void net80211_rx ( struct net80211_device *dev, struct io_buffer *iob,
1160 		   int signal, u16 rate );
1161 void net80211_rx_err ( struct net80211_device *dev,
1162 		       struct io_buffer *iob, int rc );
1163 void net80211_tx_complete ( struct net80211_device *dev,
1164 			    struct io_buffer *iob, int retries, int rc );
1165 void net80211_unregister ( struct net80211_device *dev );
1166 void net80211_free ( struct net80211_device *dev );
1167 /** @} */
1168 
1169 /**
1170  * Calculate duration field for a CTS control frame
1171  *
1172  * @v dev	802.11 device
1173  * @v size	Size of the packet being cleared to send
1174  *
1175  * A CTS control frame's duration field captures the frame being
1176  * protected and its 10-byte ACK.
1177  */
net80211_cts_duration(struct net80211_device * dev,int size)1178 static inline u16 net80211_cts_duration ( struct net80211_device *dev,
1179 					  int size )
1180 {
1181 	return ( net80211_duration ( dev, 10,
1182 				     dev->rates[dev->rtscts_rate] ) +
1183 		 net80211_duration ( dev, size, dev->rates[dev->rate] ) );
1184 }
1185 
1186 #endif
1187