Root/drivers/uwb/beacon.c

1/*
2 * Ultra Wide Band
3 * Beacon management
4 *
5 * Copyright (C) 2005-2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *
22 *
23 * FIXME: docs
24 */
25#include <linux/kernel.h>
26#include <linux/init.h>
27#include <linux/module.h>
28#include <linux/device.h>
29#include <linux/err.h>
30#include <linux/kdev_t.h>
31#include <linux/slab.h>
32
33#include "uwb-internal.h"
34
35/* Start Beaconing command structure */
36struct uwb_rc_cmd_start_beacon {
37    struct uwb_rccb rccb;
38    __le16 wBPSTOffset;
39    u8 bChannelNumber;
40} __attribute__((packed));
41
42
43static int uwb_rc_start_beacon(struct uwb_rc *rc, u16 bpst_offset, u8 channel)
44{
45    int result;
46    struct uwb_rc_cmd_start_beacon *cmd;
47    struct uwb_rc_evt_confirm reply;
48
49    cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
50    if (cmd == NULL)
51        return -ENOMEM;
52    cmd->rccb.bCommandType = UWB_RC_CET_GENERAL;
53    cmd->rccb.wCommand = cpu_to_le16(UWB_RC_CMD_START_BEACON);
54    cmd->wBPSTOffset = cpu_to_le16(bpst_offset);
55    cmd->bChannelNumber = channel;
56    reply.rceb.bEventType = UWB_RC_CET_GENERAL;
57    reply.rceb.wEvent = UWB_RC_CMD_START_BEACON;
58    result = uwb_rc_cmd(rc, "START-BEACON", &cmd->rccb, sizeof(*cmd),
59                &reply.rceb, sizeof(reply));
60    if (result < 0)
61        goto error_cmd;
62    if (reply.bResultCode != UWB_RC_RES_SUCCESS) {
63        dev_err(&rc->uwb_dev.dev,
64            "START-BEACON: command execution failed: %s (%d)\n",
65            uwb_rc_strerror(reply.bResultCode), reply.bResultCode);
66        result = -EIO;
67    }
68error_cmd:
69    kfree(cmd);
70    return result;
71}
72
73static int uwb_rc_stop_beacon(struct uwb_rc *rc)
74{
75    int result;
76    struct uwb_rccb *cmd;
77    struct uwb_rc_evt_confirm reply;
78
79    cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
80    if (cmd == NULL)
81        return -ENOMEM;
82    cmd->bCommandType = UWB_RC_CET_GENERAL;
83    cmd->wCommand = cpu_to_le16(UWB_RC_CMD_STOP_BEACON);
84    reply.rceb.bEventType = UWB_RC_CET_GENERAL;
85    reply.rceb.wEvent = UWB_RC_CMD_STOP_BEACON;
86    result = uwb_rc_cmd(rc, "STOP-BEACON", cmd, sizeof(*cmd),
87                &reply.rceb, sizeof(reply));
88    if (result < 0)
89        goto error_cmd;
90    if (reply.bResultCode != UWB_RC_RES_SUCCESS) {
91        dev_err(&rc->uwb_dev.dev,
92            "STOP-BEACON: command execution failed: %s (%d)\n",
93            uwb_rc_strerror(reply.bResultCode), reply.bResultCode);
94        result = -EIO;
95    }
96error_cmd:
97    kfree(cmd);
98    return result;
99}
100
101/*
102 * Start/stop beacons
103 *
104 * @rc: UWB Radio Controller to operate on
105 * @channel: UWB channel on which to beacon (WUSB[table
106 * 5-12]). If -1, stop beaconing.
107 * @bpst_offset: Beacon Period Start Time offset; FIXME-do zero
108 *
109 * According to WHCI 0.95 [4.13.6] the driver will only receive the RCEB
110 * of a SET IE command after the device sent the first beacon that includes
111 * the IEs specified in the SET IE command. So, after we start beaconing we
112 * check if there is anything in the IE cache and call the SET IE command
113 * if needed.
114 */
115int uwb_rc_beacon(struct uwb_rc *rc, int channel, unsigned bpst_offset)
116{
117    int result;
118    struct device *dev = &rc->uwb_dev.dev;
119
120    if (channel < 0)
121        channel = -1;
122    if (channel == -1)
123        result = uwb_rc_stop_beacon(rc);
124    else {
125        /* channel >= 0...dah */
126        result = uwb_rc_start_beacon(rc, bpst_offset, channel);
127        if (result < 0)
128            return result;
129        if (le16_to_cpu(rc->ies->wIELength) > 0) {
130            result = uwb_rc_set_ie(rc, rc->ies);
131            if (result < 0) {
132                dev_err(dev, "Cannot set new IE on device: "
133                    "%d\n", result);
134                result = uwb_rc_stop_beacon(rc);
135                channel = -1;
136                bpst_offset = 0;
137            }
138        }
139    }
140
141    if (result >= 0)
142        rc->beaconing = channel;
143    return result;
144}
145
146/*
147 * Beacon cache
148 *
149 * The purpose of this is to speed up the lookup of becon information
150 * when a new beacon arrives. The UWB Daemon uses it also to keep a
151 * tab of which devices are in radio distance and which not. When a
152 * device's beacon stays present for more than a certain amount of
153 * time, it is considered a new, usable device. When a beacon ceases
154 * to be received for a certain amount of time, it is considered that
155 * the device is gone.
156 *
157 * FIXME: use an allocator for the entries
158 * FIXME: use something faster for search than a list
159 */
160
161void uwb_bce_kfree(struct kref *_bce)
162{
163    struct uwb_beca_e *bce = container_of(_bce, struct uwb_beca_e, refcnt);
164
165    kfree(bce->be);
166    kfree(bce);
167}
168
169
170/* Find a beacon by dev addr in the cache */
171static
172struct uwb_beca_e *__uwb_beca_find_bydev(struct uwb_rc *rc,
173                     const struct uwb_dev_addr *dev_addr)
174{
175    struct uwb_beca_e *bce, *next;
176    list_for_each_entry_safe(bce, next, &rc->uwb_beca.list, node) {
177        if (!memcmp(&bce->dev_addr, dev_addr, sizeof(bce->dev_addr)))
178            goto out;
179    }
180    bce = NULL;
181out:
182    return bce;
183}
184
185/* Find a beacon by dev addr in the cache */
186static
187struct uwb_beca_e *__uwb_beca_find_bymac(struct uwb_rc *rc,
188                     const struct uwb_mac_addr *mac_addr)
189{
190    struct uwb_beca_e *bce, *next;
191    list_for_each_entry_safe(bce, next, &rc->uwb_beca.list, node) {
192        if (!memcmp(bce->mac_addr, mac_addr->data,
193                sizeof(struct uwb_mac_addr)))
194            goto out;
195    }
196    bce = NULL;
197out:
198    return bce;
199}
200
201/**
202 * uwb_dev_get_by_devaddr - get a UWB device with a specific DevAddr
203 * @rc: the radio controller that saw the device
204 * @devaddr: DevAddr of the UWB device to find
205 *
206 * There may be more than one matching device (in the case of a
207 * DevAddr conflict), but only the first one is returned.
208 */
209struct uwb_dev *uwb_dev_get_by_devaddr(struct uwb_rc *rc,
210                       const struct uwb_dev_addr *devaddr)
211{
212    struct uwb_dev *found = NULL;
213    struct uwb_beca_e *bce;
214
215    mutex_lock(&rc->uwb_beca.mutex);
216    bce = __uwb_beca_find_bydev(rc, devaddr);
217    if (bce)
218        found = uwb_dev_try_get(rc, bce->uwb_dev);
219    mutex_unlock(&rc->uwb_beca.mutex);
220
221    return found;
222}
223
224/**
225 * uwb_dev_get_by_macaddr - get a UWB device with a specific EUI-48
226 * @rc: the radio controller that saw the device
227 * @devaddr: EUI-48 of the UWB device to find
228 */
229struct uwb_dev *uwb_dev_get_by_macaddr(struct uwb_rc *rc,
230                       const struct uwb_mac_addr *macaddr)
231{
232    struct uwb_dev *found = NULL;
233    struct uwb_beca_e *bce;
234
235    mutex_lock(&rc->uwb_beca.mutex);
236    bce = __uwb_beca_find_bymac(rc, macaddr);
237    if (bce)
238        found = uwb_dev_try_get(rc, bce->uwb_dev);
239    mutex_unlock(&rc->uwb_beca.mutex);
240
241    return found;
242}
243
244/* Initialize a beacon cache entry */
245static void uwb_beca_e_init(struct uwb_beca_e *bce)
246{
247    mutex_init(&bce->mutex);
248    kref_init(&bce->refcnt);
249    stats_init(&bce->lqe_stats);
250    stats_init(&bce->rssi_stats);
251}
252
253/*
254 * Add a beacon to the cache
255 *
256 * @be: Beacon event information
257 * @bf: Beacon frame (part of b, really)
258 * @ts_jiffies: Timestamp (in jiffies) when the beacon was received
259 */
260static
261struct uwb_beca_e *__uwb_beca_add(struct uwb_rc *rc,
262                  struct uwb_rc_evt_beacon *be,
263                  struct uwb_beacon_frame *bf,
264                  unsigned long ts_jiffies)
265{
266    struct uwb_beca_e *bce;
267
268    bce = kzalloc(sizeof(*bce), GFP_KERNEL);
269    if (bce == NULL)
270        return NULL;
271    uwb_beca_e_init(bce);
272    bce->ts_jiffies = ts_jiffies;
273    bce->uwb_dev = NULL;
274    list_add(&bce->node, &rc->uwb_beca.list);
275    return bce;
276}
277
278/*
279 * Wipe out beacon entries that became stale
280 *
281 * Remove associated devicest too.
282 */
283void uwb_beca_purge(struct uwb_rc *rc)
284{
285    struct uwb_beca_e *bce, *next;
286    unsigned long expires;
287
288    mutex_lock(&rc->uwb_beca.mutex);
289    list_for_each_entry_safe(bce, next, &rc->uwb_beca.list, node) {
290        expires = bce->ts_jiffies + msecs_to_jiffies(beacon_timeout_ms);
291        if (time_after(jiffies, expires)) {
292            uwbd_dev_offair(bce);
293        }
294    }
295    mutex_unlock(&rc->uwb_beca.mutex);
296}
297
298/* Clean up the whole beacon cache. Called on shutdown */
299void uwb_beca_release(struct uwb_rc *rc)
300{
301    struct uwb_beca_e *bce, *next;
302
303    mutex_lock(&rc->uwb_beca.mutex);
304    list_for_each_entry_safe(bce, next, &rc->uwb_beca.list, node) {
305        list_del(&bce->node);
306        uwb_bce_put(bce);
307    }
308    mutex_unlock(&rc->uwb_beca.mutex);
309}
310
311static void uwb_beacon_print(struct uwb_rc *rc, struct uwb_rc_evt_beacon *be,
312                 struct uwb_beacon_frame *bf)
313{
314    char macbuf[UWB_ADDR_STRSIZE];
315    char devbuf[UWB_ADDR_STRSIZE];
316    char dstbuf[UWB_ADDR_STRSIZE];
317
318    uwb_mac_addr_print(macbuf, sizeof(macbuf), &bf->Device_Identifier);
319    uwb_dev_addr_print(devbuf, sizeof(devbuf), &bf->hdr.SrcAddr);
320    uwb_dev_addr_print(dstbuf, sizeof(dstbuf), &bf->hdr.DestAddr);
321    dev_info(&rc->uwb_dev.dev,
322         "BEACON from %s to %s (ch%u offset %u slot %u MAC %s)\n",
323         devbuf, dstbuf, be->bChannelNumber, be->wBPSTOffset,
324         bf->Beacon_Slot_Number, macbuf);
325}
326
327/*
328 * @bce: beacon cache entry, referenced
329 */
330ssize_t uwb_bce_print_IEs(struct uwb_dev *uwb_dev, struct uwb_beca_e *bce,
331              char *buf, size_t size)
332{
333    ssize_t result = 0;
334    struct uwb_rc_evt_beacon *be;
335    struct uwb_beacon_frame *bf;
336    int ies_len;
337    struct uwb_ie_hdr *ies;
338
339    mutex_lock(&bce->mutex);
340
341    be = bce->be;
342    if (be) {
343        bf = (struct uwb_beacon_frame *)bce->be->BeaconInfo;
344        ies_len = be->wBeaconInfoLength - sizeof(struct uwb_beacon_frame);
345        ies = (struct uwb_ie_hdr *)bf->IEData;
346
347        result = uwb_ie_dump_hex(ies, ies_len, buf, size);
348    }
349
350    mutex_unlock(&bce->mutex);
351
352    return result;
353}
354
355/*
356 * Verify that the beacon event, frame and IEs are ok
357 */
358static int uwb_verify_beacon(struct uwb_rc *rc, struct uwb_event *evt,
359                 struct uwb_rc_evt_beacon *be)
360{
361    int result = -EINVAL;
362    struct uwb_beacon_frame *bf;
363    struct device *dev = &rc->uwb_dev.dev;
364
365    /* Is there enough data to decode a beacon frame? */
366    if (evt->notif.size < sizeof(*be) + sizeof(*bf)) {
367        dev_err(dev, "BEACON event: Not enough data to decode "
368            "(%zu vs %zu bytes needed)\n", evt->notif.size,
369            sizeof(*be) + sizeof(*bf));
370        goto error;
371    }
372    /* FIXME: make sure beacon frame IEs are fine and that the whole thing
373     * is consistent */
374    result = 0;
375error:
376    return result;
377}
378
379/*
380 * Handle UWB_RC_EVT_BEACON events
381 *
382 * We check the beacon cache to see how the received beacon fares. If
383 * is there already we refresh the timestamp. If not we create a new
384 * entry.
385 *
386 * According to the WHCI and WUSB specs, only one beacon frame is
387 * allowed per notification block, so we don't bother about scanning
388 * for more.
389 */
390int uwbd_evt_handle_rc_beacon(struct uwb_event *evt)
391{
392    int result = -EINVAL;
393    struct uwb_rc *rc;
394    struct uwb_rc_evt_beacon *be;
395    struct uwb_beacon_frame *bf;
396    struct uwb_beca_e *bce;
397    unsigned long last_ts;
398
399    rc = evt->rc;
400    be = container_of(evt->notif.rceb, struct uwb_rc_evt_beacon, rceb);
401    result = uwb_verify_beacon(rc, evt, be);
402    if (result < 0)
403        return result;
404
405    /* FIXME: handle alien beacons. */
406    if (be->bBeaconType == UWB_RC_BEACON_TYPE_OL_ALIEN ||
407        be->bBeaconType == UWB_RC_BEACON_TYPE_NOL_ALIEN) {
408        return -ENOSYS;
409    }
410
411    bf = (struct uwb_beacon_frame *) be->BeaconInfo;
412
413    /*
414     * Drop beacons from devices with a NULL EUI-48 -- they cannot
415     * be uniquely identified.
416     *
417     * It's expected that these will all be WUSB devices and they
418     * have a WUSB specific connection method so ignoring them
419     * here shouldn't be a problem.
420     */
421    if (uwb_mac_addr_bcast(&bf->Device_Identifier))
422        return 0;
423
424    mutex_lock(&rc->uwb_beca.mutex);
425    bce = __uwb_beca_find_bymac(rc, &bf->Device_Identifier);
426    if (bce == NULL) {
427        /* Not in there, a new device is pinging */
428        uwb_beacon_print(evt->rc, be, bf);
429        bce = __uwb_beca_add(rc, be, bf, evt->ts_jiffies);
430        if (bce == NULL) {
431            mutex_unlock(&rc->uwb_beca.mutex);
432            return -ENOMEM;
433        }
434    }
435    mutex_unlock(&rc->uwb_beca.mutex);
436
437    mutex_lock(&bce->mutex);
438    /* purge old beacon data */
439    kfree(bce->be);
440
441    last_ts = bce->ts_jiffies;
442
443    /* Update commonly used fields */
444    bce->ts_jiffies = evt->ts_jiffies;
445    bce->be = be;
446    bce->dev_addr = bf->hdr.SrcAddr;
447    bce->mac_addr = &bf->Device_Identifier;
448    be->wBPSTOffset = le16_to_cpu(be->wBPSTOffset);
449    be->wBeaconInfoLength = le16_to_cpu(be->wBeaconInfoLength);
450    stats_add_sample(&bce->lqe_stats, be->bLQI - 7);
451    stats_add_sample(&bce->rssi_stats, be->bRSSI + 18);
452
453    /*
454     * This might be a beacon from a new device.
455     */
456    if (bce->uwb_dev == NULL)
457        uwbd_dev_onair(evt->rc, bce);
458
459    mutex_unlock(&bce->mutex);
460
461    return 1; /* we keep the event data */
462}
463
464/*
465 * Handle UWB_RC_EVT_BEACON_SIZE events
466 *
467 * XXXXX
468 */
469int uwbd_evt_handle_rc_beacon_size(struct uwb_event *evt)
470{
471    int result = -EINVAL;
472    struct device *dev = &evt->rc->uwb_dev.dev;
473    struct uwb_rc_evt_beacon_size *bs;
474
475    /* Is there enough data to decode the event? */
476    if (evt->notif.size < sizeof(*bs)) {
477        dev_err(dev, "BEACON SIZE notification: Not enough data to "
478            "decode (%zu vs %zu bytes needed)\n",
479            evt->notif.size, sizeof(*bs));
480        goto error;
481    }
482    bs = container_of(evt->notif.rceb, struct uwb_rc_evt_beacon_size, rceb);
483    if (0)
484        dev_info(dev, "Beacon size changed to %u bytes "
485            "(FIXME: action?)\n", le16_to_cpu(bs->wNewBeaconSize));
486    else {
487        /* temporary hack until we do something with this message... */
488        static unsigned count;
489        if (++count % 1000 == 0)
490            dev_info(dev, "Beacon size changed %u times "
491                "(FIXME: action?)\n", count);
492    }
493    result = 0;
494error:
495    return result;
496}
497
498/**
499 * uwbd_evt_handle_rc_bp_slot_change - handle a BP_SLOT_CHANGE event
500 * @evt: the BP_SLOT_CHANGE notification from the radio controller
501 *
502 * If the event indicates that no beacon period slots were available
503 * then radio controller has transitioned to a non-beaconing state.
504 * Otherwise, simply save the current beacon slot.
505 */
506int uwbd_evt_handle_rc_bp_slot_change(struct uwb_event *evt)
507{
508    struct uwb_rc *rc = evt->rc;
509    struct device *dev = &rc->uwb_dev.dev;
510    struct uwb_rc_evt_bp_slot_change *bpsc;
511
512    if (evt->notif.size < sizeof(*bpsc)) {
513        dev_err(dev, "BP SLOT CHANGE event: Not enough data\n");
514        return -EINVAL;
515    }
516    bpsc = container_of(evt->notif.rceb, struct uwb_rc_evt_bp_slot_change, rceb);
517
518    mutex_lock(&rc->uwb_dev.mutex);
519    if (uwb_rc_evt_bp_slot_change_no_slot(bpsc)) {
520        dev_info(dev, "stopped beaconing: No free slots in BP\n");
521        rc->beaconing = -1;
522    } else
523        rc->uwb_dev.beacon_slot = uwb_rc_evt_bp_slot_change_slot_num(bpsc);
524    mutex_unlock(&rc->uwb_dev.mutex);
525
526    return 0;
527}
528
529/**
530 * Handle UWB_RC_EVT_BPOIE_CHANGE events
531 *
532 * XXXXX
533 */
534struct uwb_ie_bpo {
535    struct uwb_ie_hdr hdr;
536    u8 bp_length;
537    u8 data[];
538} __attribute__((packed));
539
540int uwbd_evt_handle_rc_bpoie_change(struct uwb_event *evt)
541{
542    int result = -EINVAL;
543    struct device *dev = &evt->rc->uwb_dev.dev;
544    struct uwb_rc_evt_bpoie_change *bpoiec;
545    struct uwb_ie_bpo *bpoie;
546    static unsigned count; /* FIXME: this is a temp hack */
547    size_t iesize;
548
549    /* Is there enough data to decode it? */
550    if (evt->notif.size < sizeof(*bpoiec)) {
551        dev_err(dev, "BPOIEC notification: Not enough data to "
552            "decode (%zu vs %zu bytes needed)\n",
553            evt->notif.size, sizeof(*bpoiec));
554        goto error;
555    }
556    bpoiec = container_of(evt->notif.rceb, struct uwb_rc_evt_bpoie_change, rceb);
557    iesize = le16_to_cpu(bpoiec->wBPOIELength);
558    if (iesize < sizeof(*bpoie)) {
559        dev_err(dev, "BPOIEC notification: Not enough IE data to "
560            "decode (%zu vs %zu bytes needed)\n",
561            iesize, sizeof(*bpoie));
562        goto error;
563    }
564    if (++count % 1000 == 0) /* Lame placeholder */
565        dev_info(dev, "BPOIE: %u changes received\n", count);
566    /*
567     * FIXME: At this point we should go over all the IEs in the
568     * bpoiec->BPOIE array and act on each.
569     */
570    result = 0;
571error:
572    return result;
573}
574
575/*
576 * Print beaconing state.
577 */
578static ssize_t uwb_rc_beacon_show(struct device *dev,
579                  struct device_attribute *attr, char *buf)
580{
581    struct uwb_dev *uwb_dev = to_uwb_dev(dev);
582    struct uwb_rc *rc = uwb_dev->rc;
583    ssize_t result;
584
585    mutex_lock(&rc->uwb_dev.mutex);
586    result = sprintf(buf, "%d\n", rc->beaconing);
587    mutex_unlock(&rc->uwb_dev.mutex);
588    return result;
589}
590
591/*
592 * Start beaconing on the specified channel, or stop beaconing.
593 */
594static ssize_t uwb_rc_beacon_store(struct device *dev,
595                   struct device_attribute *attr,
596                   const char *buf, size_t size)
597{
598    struct uwb_dev *uwb_dev = to_uwb_dev(dev);
599    struct uwb_rc *rc = uwb_dev->rc;
600    int channel;
601    ssize_t result = -EINVAL;
602
603    result = sscanf(buf, "%d", &channel);
604    if (result >= 1)
605        result = uwb_radio_force_channel(rc, channel);
606
607    return result < 0 ? result : size;
608}
609DEVICE_ATTR(beacon, S_IRUGO | S_IWUSR, uwb_rc_beacon_show, uwb_rc_beacon_store);
610

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