aboutsummaryrefslogtreecommitdiffstats
path: root/net/caif/cfpkt_skbuff.c
blob: c49a6695793ac8361b072077aefa4e2b863e8f5c (plain) (blame)
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
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
 * License terms: GNU General Public License (GPL) version 2
 */

#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/hardirq.h>
#include <net/caif/cfpkt.h>

#define PKT_PREFIX  48
#define PKT_POSTFIX 2
#define PKT_LEN_WHEN_EXTENDING 128
#define PKT_ERROR(pkt, errmsg) do {	   \
    cfpkt_priv(pkt)->erronous = true;	   \
    skb_reset_tail_pointer(&pkt->skb);	   \
    pr_warning("CAIF: " errmsg);\
  } while (0)

struct cfpktq {
	struct sk_buff_head head;
	atomic_t count;
	/* Lock protects count updates */
	spinlock_t lock;
};

/*
 * net/caif/ is generic and does not
 * understand SKB, so we do this typecast
 */
struct cfpkt {
	struct sk_buff skb;
};

/* Private data inside SKB */
struct cfpkt_priv_data {
	struct dev_info dev_info;
	bool erronous;
};

inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
{
	return (struct cfpkt_priv_data *) pkt->skb.cb;
}

inline bool is_erronous(struct cfpkt *pkt)
{
	return cfpkt_priv(pkt)->erronous;
}

inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
{
	return &pkt->skb;
}

inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
{
	return (struct cfpkt *) skb;
}


struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
{
	struct cfpkt *pkt = skb_to_pkt(nativepkt);
	cfpkt_priv(pkt)->erronous = false;
	return pkt;
}
EXPORT_SYMBOL(cfpkt_fromnative);

void *cfpkt_tonative(struct cfpkt *pkt)
{
	return (void *) pkt;
}
EXPORT_SYMBOL(cfpkt_tonative);

static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
{
	struct sk_buff *skb;

	if (likely(in_interrupt()))
		skb = alloc_skb(len + pfx, GFP_ATOMIC);
	else
		skb = alloc_skb(len + pfx, GFP_KERNEL);

	if (unlikely(skb == NULL))
		return NULL;

	skb_reserve(skb, pfx);
	return skb_to_pkt(skb);
}

inline struct cfpkt *cfpkt_create(u16 len)
{
	return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
}
EXPORT_SYMBOL(cfpkt_create);

void cfpkt_destroy(struct cfpkt *pkt)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	kfree_skb(skb);
}
EXPORT_SYMBOL(cfpkt_destroy);

inline bool cfpkt_more(struct cfpkt *pkt)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	return skb->len > 0;
}
EXPORT_SYMBOL(cfpkt_more);

int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	if (skb_headlen(skb) >= len) {
		memcpy(data, skb->data, len);
		return 0;
	}
	return !cfpkt_extr_head(pkt, data, len) &&
	    !cfpkt_add_head(pkt, data, len);
}
EXPORT_SYMBOL(cfpkt_peek_head);

int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	u8 *from;
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;

	if (unlikely(len > skb->len)) {
		PKT_ERROR(pkt, "cfpkt_extr_head read beyond end of packet\n");
		return -EPROTO;
	}

	if (unlikely(len > skb_headlen(skb))) {
		if (unlikely(skb_linearize(skb) != 0)) {
			PKT_ERROR(pkt, "cfpkt_extr_head linearize failed\n");
			return -EPROTO;
		}
	}
	from = skb_pull(skb, len);
	from -= len;
	memcpy(data, from, len);
	return 0;
}
EXPORT_SYMBOL(cfpkt_extr_head);

int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	u8 *data = dta;
	u8 *from;
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;

	if (unlikely(skb_linearize(skb) != 0)) {
		PKT_ERROR(pkt, "cfpkt_extr_trail linearize failed\n");
		return -EPROTO;
	}
	if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
		PKT_ERROR(pkt, "cfpkt_extr_trail read beyond end of packet\n");
		return -EPROTO;
	}
	from = skb_tail_pointer(skb) - len;
	skb_trim(skb, skb->len - len);
	memcpy(data, from, len);
	return 0;
}
EXPORT_SYMBOL(cfpkt_extr_trail);

int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
{
	return cfpkt_add_body(pkt, NULL, len);
}
EXPORT_SYMBOL(cfpkt_pad_trail);

int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	struct sk_buff *lastskb;
	u8 *to;
	u16 addlen = 0;


	if (unlikely(is_erronous(pkt)))
		return -EPROTO;

	lastskb = skb;

	/* Check whether we need to add space at the tail */
	if (unlikely(skb_tailroom(skb) < len)) {
		if (likely(len < PKT_LEN_WHEN_EXTENDING))
			addlen = PKT_LEN_WHEN_EXTENDING;
		else
			addlen = len;
	}

	/* Check whether we need to change the SKB before writing to the tail */
	if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {

		/* Make sure data is writable */
		if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
			PKT_ERROR(pkt, "cfpkt_add_body: cow failed\n");
			return -EPROTO;
		}
		/*
		 * Is the SKB non-linear after skb_cow_data()? If so, we are
		 * going to add data to the last SKB, so we need to adjust
		 * lengths of the top SKB.
		 */
		if (lastskb != skb) {
			pr_warning("CAIF: %s(): Packet is non-linear\n",
				   __func__);
			skb->len += len;
			skb->data_len += len;
		}
	}

	/* All set to put the last SKB and optionally write data there. */
	to = skb_put(lastskb, len);
	if (likely(data))
		memcpy(to, data, len);
	return 0;
}
EXPORT_SYMBOL(cfpkt_add_body);

inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
{
	return cfpkt_add_body(pkt, &data, 1);
}
EXPORT_SYMBOL(cfpkt_addbdy);

int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	struct sk_buff *lastskb;
	u8 *to;
	const u8 *data = data2;
	int ret;
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;
	if (unlikely(skb_headroom(skb) < len)) {
		PKT_ERROR(pkt, "cfpkt_add_head: no headroom\n");
		return -EPROTO;
	}

	/* Make sure data is writable */
	ret = skb_cow_data(skb, 0, &lastskb);
	if (unlikely(ret < 0)) {
		PKT_ERROR(pkt, "cfpkt_add_head: cow failed\n");
		return ret;
	}

	to = skb_push(skb, len);
	memcpy(to, data, len);
	return 0;
}
EXPORT_SYMBOL(cfpkt_add_head);

inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
{
	return cfpkt_add_body(pkt, data, len);
}
EXPORT_SYMBOL(cfpkt_add_trail);

inline u16 cfpkt_getlen(struct cfpkt *pkt)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	return skb->len;
}
EXPORT_SYMBOL(cfpkt_getlen);

inline u16 cfpkt_iterate(struct cfpkt *pkt,
			    u16 (*iter_func)(u16, void *, u16),
			    u16 data)
{
	/*
	 * Don't care about the performance hit of linearizing,
	 * Checksum should not be used on high-speed interfaces anyway.
	 */
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;
	if (unlikely(skb_linearize(&pkt->skb) != 0)) {
		PKT_ERROR(pkt, "cfpkt_iterate: linearize failed\n");
		return -EPROTO;
	}
	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
}
EXPORT_SYMBOL(cfpkt_iterate);

int cfpkt_setlen(struct cfpkt *pkt, u16 len)
{
	struct sk_buff *skb = pkt_to_skb(pkt);


	if (unlikely(is_erronous(pkt)))
		return -EPROTO;

	if (likely(len <= skb->len)) {
		if (unlikely(skb->data_len))
			___pskb_trim(skb, len);
		else
			skb_trim(skb, len);

			return cfpkt_getlen(pkt);
	}

	/* Need to expand SKB */
	if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
		PKT_ERROR(pkt, "cfpkt_setlen: skb_pad_trail failed\n");

	return cfpkt_getlen(pkt);
}
EXPORT_SYMBOL(cfpkt_setlen);

struct cfpkt *cfpkt_create_uplink(const unsigned char *data, unsigned int len)
{
	struct cfpkt *pkt = cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
	if (!pkt)
		return NULL;
	if (unlikely(data != NULL))
		cfpkt_add_body(pkt, data, len);
	return pkt;
}
EXPORT_SYMBOL(cfpkt_create_uplink);

struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
			     struct cfpkt *addpkt,
			     u16 expectlen)
{
	struct sk_buff *dst = pkt_to_skb(dstpkt);
	struct sk_buff *add = pkt_to_skb(addpkt);
	u16 addlen = skb_headlen(add);
	u16 neededtailspace;
	struct sk_buff *tmp;
	u16 dstlen;
	u16 createlen;
	if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
		return dstpkt;
	}
	if (expectlen > addlen)
		neededtailspace = expectlen;
	else
		neededtailspace = addlen;

	if (dst->tail + neededtailspace > dst->end) {
		/* Create a dumplicate of 'dst' with more tail space */
		struct cfpkt *tmppkt;
		dstlen = skb_headlen(dst);
		createlen = dstlen + neededtailspace;
		tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
		if (tmppkt == NULL)
			return NULL;
		tmp = pkt_to_skb(tmppkt);
		skb_set_tail_pointer(tmp, dstlen);
		tmp->len = dstlen;
		memcpy(tmp->data, dst->data, dstlen);
		cfpkt_destroy(dstpkt);
		dst = tmp;
	}
	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
	cfpkt_destroy(addpkt);
	dst->tail += addlen;
	dst->len += addlen;
	return skb_to_pkt(dst);
}
EXPORT_SYMBOL(cfpkt_append);

struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
{
	struct sk_buff *skb2;
	struct sk_buff *skb = pkt_to_skb(pkt);
	struct cfpkt *tmppkt;
	u8 *split = skb->data + pos;
	u16 len2nd = skb_tail_pointer(skb) - split;

	if (unlikely(is_erronous(pkt)))
		return NULL;

	if (skb->data + pos > skb_tail_pointer(skb)) {
		PKT_ERROR(pkt,
			  "cfpkt_split: trying to split beyond end of packet");
		return NULL;
	}

	/* Create a new packet for the second part of the data */
	tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
				  PKT_PREFIX);
	if (tmppkt == NULL)
		return NULL;
	skb2 = pkt_to_skb(tmppkt);


	if (skb2 == NULL)
		return NULL;

	/* Reduce the length of the original packet */
	skb_set_tail_pointer(skb, pos);
	skb->len = pos;

	memcpy(skb2->data, split, len2nd);
	skb2->tail += len2nd;
	skb2->len += len2nd;
	return skb_to_pkt(skb2);
}
EXPORT_SYMBOL(cfpkt_split);

char *cfpkt_log_pkt(struct cfpkt *pkt, char *buf, int buflen)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	char *p = buf;
	int i;

	/*
	 * Sanity check buffer length, it needs to be at least as large as
	 * the header info: ~=50+ bytes
	 */
	if (buflen < 50)
		return NULL;

	snprintf(buf, buflen, "%s: pkt:%p len:%ld(%ld+%ld) {%ld,%ld} data: [",
		is_erronous(pkt) ? "ERRONOUS-SKB" :
		 (skb->data_len != 0 ? "COMPLEX-SKB" : "SKB"),
		 skb,
		 (long) skb->len,
		 (long) (skb_tail_pointer(skb) - skb->data),
		 (long) skb->data_len,
		 (long) (skb->data - skb->head),
		 (long) (skb_tail_pointer(skb) - skb->head));
	p = buf + strlen(buf);

	for (i = 0; i < skb_tail_pointer(skb) - skb->data && i < 300; i++) {
		if (p > buf + buflen - 10) {
			sprintf(p, "...");
			p = buf + strlen(buf);
			break;
		}
		sprintf(p, "%02x,", skb->data[i]);
		p = buf + strlen(buf);
	}
	sprintf(p, "]\n");
	return buf;
}
EXPORT_SYMBOL(cfpkt_log_pkt);

int cfpkt_raw_append(struct cfpkt *pkt, void **buf, unsigned int buflen)
{
	struct sk_buff *skb = pkt_to_skb(pkt);
	struct sk_buff *lastskb;

	caif_assert(buf != NULL);
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;
	/* Make sure SKB is writable */
	if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
		PKT_ERROR(pkt, "cfpkt_raw_append: skb_cow_data failed\n");
		return -EPROTO;
	}

	if (unlikely(skb_linearize(skb) != 0)) {
		PKT_ERROR(pkt, "cfpkt_raw_append: linearize failed\n");
		return -EPROTO;
	}

	if (unlikely(skb_tailroom(skb) < buflen)) {
		PKT_ERROR(pkt, "cfpkt_raw_append: buffer too short - failed\n");
		return -EPROTO;
	}

	*buf = skb_put(skb, buflen);
	return 1;
}
EXPORT_SYMBOL(cfpkt_raw_append);

int cfpkt_raw_extract(struct cfpkt *pkt, void **buf, unsigned int buflen)
{
	struct sk_buff *skb = pkt_to_skb(pkt);

	caif_assert(buf != NULL);
	if (unlikely(is_erronous(pkt)))
		return -EPROTO;

	if (unlikely(buflen > skb->len)) {
		PKT_ERROR(pkt, "cfpkt_raw_extract: buflen too large "
				"- failed\n");
		return -EPROTO;
	}

	if (unlikely(buflen > skb_headlen(skb))) {
		if (unlikely(skb_linearize(skb) != 0)) {
			PKT_ERROR(pkt, "cfpkt_raw_extract: linearize failed\n");
			return -EPROTO;
		}
	}

	*buf = skb->data;
	skb_pull(skb, buflen);

	return 1;
}
EXPORT_SYMBOL(cfpkt_raw_extract);

inline bool cfpkt_erroneous(struct cfpkt *pkt)
{
	return cfpkt_priv(pkt)->erronous;
}
EXPORT_SYMBOL(cfpkt_erroneous);

struct cfpktq *cfpktq_create(void)
{
	struct cfpktq *q = kmalloc(sizeof(struct cfpktq), GFP_ATOMIC);
	if (!q)
		return NULL;
	skb_queue_head_init(&q->head);
	atomic_set(&q->count, 0);
	spin_lock_init(&q->lock);
	return q;
}
EXPORT_SYMBOL(cfpktq_create);

void cfpkt_queue(struct cfpktq *pktq, struct cfpkt *pkt, unsigned short prio)
{
	atomic_inc(&pktq->count);
	spin_lock(&pktq->lock);
	skb_queue_tail(&pktq->head, pkt_to_skb(pkt));
	spin_unlock(&pktq->lock);

}
EXPORT_SYMBOL(cfpkt_queue);

struct cfpkt *cfpkt_qpeek(struct cfpktq *pktq)
{
	struct cfpkt *tmp;
	spin_lock(&pktq->lock);
	tmp = skb_to_pkt(skb_peek(&pktq->head));
	spin_unlock(&pktq->lock);
	return tmp;
}
EXPORT_SYMBOL(cfpkt_qpeek);

struct cfpkt *cfpkt_dequeue(struct cfpktq *pktq)
{
	struct cfpkt *pkt;
	spin_lock(&pktq->lock);
	pkt = skb_to_pkt(skb_dequeue(&pktq->head));
	if (pkt) {
		atomic_dec(&pktq->count);
		caif_assert(atomic_read(&pktq->count) >= 0);
	}
	spin_unlock(&pktq->lock);
	return pkt;
}
EXPORT_SYMBOL(cfpkt_dequeue);

int cfpkt_qcount(struct cfpktq *pktq)
{
	return atomic_read(&pktq->count);
}
EXPORT_SYMBOL(cfpkt_qcount);

struct cfpkt *cfpkt_clone_release(struct cfpkt *pkt)
{
	struct cfpkt *clone;
	clone  = skb_to_pkt(skb_clone(pkt_to_skb(pkt), GFP_ATOMIC));
	/* Free original packet. */
	cfpkt_destroy(pkt);
	if (!clone)
		return NULL;
	return clone;
}
EXPORT_SYMBOL(cfpkt_clone_release);

struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
{
	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
}
EXPORT_SYMBOL(cfpkt_info);