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