summaryrefslogtreecommitdiff
path: root/drivers/net/wimax/i2400m/rx.c
blob: c62b8c564161b566995484470100de6773244467 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
/*
 * Intel Wireless WiMAX Connection 2400m
 * Handle incoming traffic and deliver it to the control or data planes
 *
 *
 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * Intel Corporation <linux-wimax@intel.com>
 * Yanir Lubetkin <yanirx.lubetkin@intel.com>
 *  - Initial implementation
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *  - Use skb_clone(), break up processing in chunks
 *  - Split transport/device specific
 *  - Make buffer size dynamic to exert less memory pressure
 *
 *
 * This handles the RX path.
 *
 * We receive an RX message from the bus-specific driver, which
 * contains one or more payloads that have potentially different
 * destinataries (data or control paths).
 *
 * So we just take that payload from the transport specific code in
 * the form of an skb, break it up in chunks (a cloned skb each in the
 * case of network packets) and pass it to netdev or to the
 * command/ack handler (and from there to the WiMAX stack).
 *
 * PROTOCOL FORMAT
 *
 * The format of the buffer is:
 *
 * HEADER                      (struct i2400m_msg_hdr)
 * PAYLOAD DESCRIPTOR 0        (struct i2400m_pld)
 * PAYLOAD DESCRIPTOR 1
 * ...
 * PAYLOAD DESCRIPTOR N
 * PAYLOAD 0                   (raw bytes)
 * PAYLOAD 1
 * ...
 * PAYLOAD N
 *
 * See tx.c for a deeper description on alignment requirements and
 * other fun facts of it.
 *
 * ROADMAP
 *
 * i2400m_rx
 *   i2400m_rx_msg_hdr_check
 *   i2400m_rx_pl_descr_check
 *   i2400m_rx_payload
 *     i2400m_net_rx
 *     i2400m_rx_ctl
 *       i2400m_msg_size_check
 *       i2400m_report_hook_work    [in a workqueue]
 *         i2400m_report_hook
 *       wimax_msg_to_user
 *       i2400m_rx_ctl_ack
 *         wimax_msg_to_user_alloc
 *     i2400m_rx_trace
 *       i2400m_msg_size_check
 *       wimax_msg
 */
#include <linux/kernel.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/workqueue.h>
#include "i2400m.h"


#define D_SUBMODULE rx
#include "debug-levels.h"

struct i2400m_report_hook_args {
	struct sk_buff *skb_rx;
	const struct i2400m_l3l4_hdr *l3l4_hdr;
	size_t size;
};


/*
 * Execute i2400m_report_hook in a workqueue
 *
 * Unpacks arguments from the deferred call, executes it and then
 * drops the references.
 *
 * Obvious NOTE: References are needed because we are a separate
 *     thread; otherwise the buffer changes under us because it is
 *     released by the original caller.
 */
static
void i2400m_report_hook_work(struct work_struct *ws)
{
	struct i2400m_work *iw =
		container_of(ws, struct i2400m_work, ws);
	struct i2400m_report_hook_args *args = (void *) iw->pl;
	i2400m_report_hook(iw->i2400m, args->l3l4_hdr, args->size);
	kfree_skb(args->skb_rx);
	i2400m_put(iw->i2400m);
	kfree(iw);
}


/*
 * Process an ack to a command
 *
 * @i2400m: device descriptor
 * @payload: pointer to message
 * @size: size of the message
 *
 * Pass the acknodledgment (in an skb) to the thread that is waiting
 * for it in i2400m->msg_completion.
 *
 * We need to coordinate properly with the thread waiting for the
 * ack. Check if it is waiting or if it is gone. We loose the spinlock
 * to avoid allocating on atomic contexts (yeah, could use GFP_ATOMIC,
 * but this is not so speed critical).
 */
static
void i2400m_rx_ctl_ack(struct i2400m *i2400m,
		       const void *payload, size_t size)
{
	struct device *dev = i2400m_dev(i2400m);
	struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
	unsigned long flags;
	struct sk_buff *ack_skb;

	/* Anyone waiting for an answer? */
	spin_lock_irqsave(&i2400m->rx_lock, flags);
	if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
		dev_err(dev, "Huh? reply to command with no waiters\n");
		goto error_no_waiter;
	}
	spin_unlock_irqrestore(&i2400m->rx_lock, flags);

	ack_skb = wimax_msg_alloc(wimax_dev, NULL, payload, size, GFP_KERNEL);

	/* Check waiter didn't time out waiting for the answer... */
	spin_lock_irqsave(&i2400m->rx_lock, flags);
	if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
		d_printf(1, dev, "Huh? waiter for command reply cancelled\n");
		goto error_waiter_cancelled;
	}
	if (ack_skb == NULL) {
		dev_err(dev, "CMD/GET/SET ack: cannot allocate SKB\n");
		i2400m->ack_skb = ERR_PTR(-ENOMEM);
	} else
		i2400m->ack_skb = ack_skb;
	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
	complete(&i2400m->msg_completion);
	return;

error_waiter_cancelled:
	kfree_skb(ack_skb);
error_no_waiter:
	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
	return;
}


/*
 * Receive and process a control payload
 *
 * @i2400m: device descriptor
 * @skb_rx: skb that contains the payload (for reference counting)
 * @payload: pointer to message
 * @size: size of the message
 *
 * There are two types of control RX messages: reports (asynchronous,
 * like your every day interrupts) and 'acks' (reponses to a command,
 * get or set request).
 *
 * If it is a report, we run hooks on it (to extract information for
 * things we need to do in the driver) and then pass it over to the
 * WiMAX stack to send it to user space.
 *
 * NOTE: report processing is done in a workqueue specific to the
 *     generic driver, to avoid deadlocks in the system.
 *
 * If it is not a report, it is an ack to a previously executed
 * command, set or get, so wake up whoever is waiting for it from
 * i2400m_msg_to_dev(). i2400m_rx_ctl_ack() takes care of that.
 *
 * Note that the sizes we pass to other functions from here are the
 * sizes of the _l3l4_hdr + payload, not full buffer sizes, as we have
 * verified in _msg_size_check() that they are congruent.
 *
 * For reports: We can't clone the original skb where the data is
 * because we need to send this up via netlink; netlink has to add
 * headers and we can't overwrite what's preceeding the payload...as
 * it is another message. So we just dup them.
 */
static
void i2400m_rx_ctl(struct i2400m *i2400m, struct sk_buff *skb_rx,
		   const void *payload, size_t size)
{
	int result;
	struct device *dev = i2400m_dev(i2400m);
	const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
	unsigned msg_type;

	result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
	if (result < 0) {
		dev_err(dev, "HW BUG? device sent a bad message: %d\n",
			result);
		goto error_check;
	}
	msg_type = le16_to_cpu(l3l4_hdr->type);
	d_printf(1, dev, "%s 0x%04x: %zu bytes\n",
		 msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
		 msg_type, size);
	d_dump(2, dev, l3l4_hdr, size);
	if (msg_type & I2400M_MT_REPORT_MASK) {
		/* These hooks have to be ran serialized; as well, the
		 * handling might force the execution of commands, and
		 * that might cause reentrancy issues with
		 * bus-specific subdrivers and workqueues. So we run
		 * it in a separate workqueue. */
		struct i2400m_report_hook_args args = {
			.skb_rx = skb_rx,
			.l3l4_hdr = l3l4_hdr,
			.size = size
		};
		if (unlikely(i2400m->ready == 0))	/* only send if up */
			return;
		skb_get(skb_rx);
		i2400m_queue_work(i2400m, i2400m_report_hook_work,
				  GFP_KERNEL, &args, sizeof(args));
		result = wimax_msg(&i2400m->wimax_dev, NULL, l3l4_hdr, size,
				   GFP_KERNEL);
		if (result < 0)
			dev_err(dev, "error sending report to userspace: %d\n",
				result);
	} else		/* an ack to a CMD, GET or SET */
		i2400m_rx_ctl_ack(i2400m, payload, size);
error_check:
	return;
}




/*
 * Receive and send up a trace
 *
 * @i2400m: device descriptor
 * @skb_rx: skb that contains the trace (for reference counting)
 * @payload: pointer to trace message inside the skb
 * @size: size of the message
 *
 * THe i2400m might produce trace information (diagnostics) and we
 * send them through a different kernel-to-user pipe (to avoid
 * clogging it).
 *
 * As in i2400m_rx_ctl(), we can't clone the original skb where the
 * data is because we need to send this up via netlink; netlink has to
 * add headers and we can't overwrite what's preceeding the
 * payload...as it is another message. So we just dup them.
 */
static
void i2400m_rx_trace(struct i2400m *i2400m,
		     const void *payload, size_t size)
{
	int result;
	struct device *dev = i2400m_dev(i2400m);
	struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
	const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
	unsigned msg_type;

	result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
	if (result < 0) {
		dev_err(dev, "HW BUG? device sent a bad trace message: %d\n",
			result);
		goto error_check;
	}
	msg_type = le16_to_cpu(l3l4_hdr->type);
	d_printf(1, dev, "Trace %s 0x%04x: %zu bytes\n",
		 msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
		 msg_type, size);
	d_dump(2, dev, l3l4_hdr, size);
	if (unlikely(i2400m->ready == 0))	/* only send if up */
		return;
	result = wimax_msg(wimax_dev, "trace", l3l4_hdr, size, GFP_KERNEL);
	if (result < 0)
		dev_err(dev, "error sending trace to userspace: %d\n",
			result);
error_check:
	return;
}


/*
 * Act on a received payload
 *
 * @i2400m: device instance
 * @skb_rx: skb where the transaction was received
 * @single: 1 if there is only one payload, 0 otherwise
 * @pld: payload descriptor
 * @payload: payload data
 *
 * Upon reception of a payload, look at its guts in the payload
 * descriptor and decide what to do with it.
 */
static
void i2400m_rx_payload(struct i2400m *i2400m, struct sk_buff *skb_rx,
		       unsigned single, const struct i2400m_pld *pld,
		       const void *payload)
{
	struct device *dev = i2400m_dev(i2400m);
	size_t pl_size = i2400m_pld_size(pld);
	enum i2400m_pt pl_type = i2400m_pld_type(pld);

	switch (pl_type) {
	case I2400M_PT_DATA:
		d_printf(3, dev, "RX: data payload %zu bytes\n", pl_size);
		i2400m_net_rx(i2400m, skb_rx, single, payload, pl_size);
		break;
	case I2400M_PT_CTRL:
		i2400m_rx_ctl(i2400m, skb_rx, payload, pl_size);
		break;
	case I2400M_PT_TRACE:
		i2400m_rx_trace(i2400m, payload, pl_size);
		break;
	default:	/* Anything else shouldn't come to the host */
		if (printk_ratelimit())
			dev_err(dev, "RX: HW BUG? unexpected payload type %u\n",
				pl_type);
	}
}


/*
 * Check a received transaction's message header
 *
 * @i2400m: device descriptor
 * @msg_hdr: message header
 * @buf_size: size of the received buffer
 *
 * Check that the declarations done by a RX buffer message header are
 * sane and consistent with the amount of data that was received.
 */
static
int i2400m_rx_msg_hdr_check(struct i2400m *i2400m,
			    const struct i2400m_msg_hdr *msg_hdr,
			    size_t buf_size)
{
	int result = -EIO;
	struct device *dev = i2400m_dev(i2400m);
	if (buf_size < sizeof(*msg_hdr)) {
		dev_err(dev, "RX: HW BUG? message with short header (%zu "
			"vs %zu bytes expected)\n", buf_size, sizeof(*msg_hdr));
		goto error;
	}
	if (msg_hdr->barker != cpu_to_le32(I2400M_D2H_MSG_BARKER)) {
		dev_err(dev, "RX: HW BUG? message received with unknown "
			"barker 0x%08x (buf_size %zu bytes)\n",
			le32_to_cpu(msg_hdr->barker), buf_size);
		goto error;
	}
	if (msg_hdr->num_pls == 0) {
		dev_err(dev, "RX: HW BUG? zero payload packets in message\n");
		goto error;
	}
	if (le16_to_cpu(msg_hdr->num_pls) > I2400M_MAX_PLS_IN_MSG) {
		dev_err(dev, "RX: HW BUG? message contains more payload "
			"than maximum; ignoring.\n");
		goto error;
	}
	result = 0;
error:
	return result;
}


/*
 * Check a payload descriptor against the received data
 *
 * @i2400m: device descriptor
 * @pld: payload descriptor
 * @pl_itr: offset (in bytes) in the received buffer the payload is
 *          located
 * @buf_size: size of the received buffer
 *
 * Given a payload descriptor (part of a RX buffer), check it is sane
 * and that the data it declares fits in the buffer.
 */
static
int i2400m_rx_pl_descr_check(struct i2400m *i2400m,
			      const struct i2400m_pld *pld,
			      size_t pl_itr, size_t buf_size)
{
	int result = -EIO;
	struct device *dev = i2400m_dev(i2400m);
	size_t pl_size = i2400m_pld_size(pld);
	enum i2400m_pt pl_type = i2400m_pld_type(pld);

	if (pl_size > i2400m->bus_pl_size_max) {
		dev_err(dev, "RX: HW BUG? payload @%zu: size %zu is "
			"bigger than maximum %zu; ignoring message\n",
			pl_itr, pl_size, i2400m->bus_pl_size_max);
		goto error;
	}
	if (pl_itr + pl_size > buf_size) {	/* enough? */
		dev_err(dev, "RX: HW BUG? payload @%zu: size %zu "
			"goes beyond the received buffer "
			"size (%zu bytes); ignoring message\n",
			pl_itr, pl_size, buf_size);
		goto error;
	}
	if (pl_type >= I2400M_PT_ILLEGAL) {
		dev_err(dev, "RX: HW BUG? illegal payload type %u; "
			"ignoring message\n", pl_type);
		goto error;
	}
	result = 0;
error:
	return result;
}


/**
 * i2400m_rx - Receive a buffer of data from the device
 *
 * @i2400m: device descriptor
 * @skb: skbuff where the data has been received
 *
 * Parse in a buffer of data that contains an RX message sent from the
 * device. See the file header for the format. Run all checks on the
 * buffer header, then run over each payload's descriptors, verify
 * their consistency and act on each payload's contents.  If
 * everything is succesful, update the device's statistics.
 *
 * Note: You need to set the skb to contain only the length of the
 * received buffer; for that, use skb_trim(skb, RECEIVED_SIZE).
 *
 * Returns:
 *
 * 0 if ok, < 0 errno on error
 *
 * If ok, this function owns now the skb and the caller DOESN'T have
 * to run kfree_skb() on it. However, on error, the caller still owns
 * the skb and it is responsible for releasing it.
 */
int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
{
	int i, result;
	struct device *dev = i2400m_dev(i2400m);
	const struct i2400m_msg_hdr *msg_hdr;
	size_t pl_itr, pl_size, skb_len;
	unsigned long flags;
	unsigned num_pls;

	skb_len = skb->len;
	d_fnstart(4, dev, "(i2400m %p skb %p [size %zu])\n",
		  i2400m, skb, skb_len);
	result = -EIO;
	msg_hdr = (void *) skb->data;
	result = i2400m_rx_msg_hdr_check(i2400m, msg_hdr, skb->len);
	if (result < 0)
		goto error_msg_hdr_check;
	result = -EIO;
	num_pls = le16_to_cpu(msg_hdr->num_pls);
	pl_itr = sizeof(*msg_hdr) +	/* Check payload descriptor(s) */
		num_pls * sizeof(msg_hdr->pld[0]);
	pl_itr = ALIGN(pl_itr, I2400M_PL_PAD);
	if (pl_itr > skb->len) {	/* got all the payload descriptors? */
		dev_err(dev, "RX: HW BUG? message too short (%u bytes) for "
			"%u payload descriptors (%zu each, total %zu)\n",
			skb->len, num_pls, sizeof(msg_hdr->pld[0]), pl_itr);
		goto error_pl_descr_short;
	}
	/* Walk each payload payload--check we really got it */
	for (i = 0; i < num_pls; i++) {
		/* work around old gcc warnings */
		pl_size = i2400m_pld_size(&msg_hdr->pld[i]);
		result = i2400m_rx_pl_descr_check(i2400m, &msg_hdr->pld[i],
						  pl_itr, skb->len);
		if (result < 0)
			goto error_pl_descr_check;
		i2400m_rx_payload(i2400m, skb, num_pls == 1, &msg_hdr->pld[i],
				  skb->data + pl_itr);
		pl_itr += ALIGN(pl_size, I2400M_PL_PAD);
		cond_resched();		/* Don't monopolize */
	}
	kfree_skb(skb);
	/* Update device statistics */
	spin_lock_irqsave(&i2400m->rx_lock, flags);
	i2400m->rx_pl_num += i;
	if (i > i2400m->rx_pl_max)
		i2400m->rx_pl_max = i;
	if (i < i2400m->rx_pl_min)
		i2400m->rx_pl_min = i;
	i2400m->rx_num++;
	i2400m->rx_size_acc += skb->len;
	if (skb->len < i2400m->rx_size_min)
		i2400m->rx_size_min = skb->len;
	if (skb->len > i2400m->rx_size_max)
		i2400m->rx_size_max = skb->len;
	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
error_pl_descr_check:
error_pl_descr_short:
error_msg_hdr_check:
	d_fnend(4, dev, "(i2400m %p skb %p [size %zu]) = %d\n",
		i2400m, skb, skb_len, result);
	return result;
}
EXPORT_SYMBOL_GPL(i2400m_rx);