1/*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
4 * License terms: GNU General Public License (GPL) version 2
5 */
6
7#include <linux/string.h>
8#include <linux/skbuff.h>
9#include <linux/hardirq.h>
10#include <net/caif/cfpkt.h>
11
12#define PKT_PREFIX  48
13#define PKT_POSTFIX 2
14#define PKT_LEN_WHEN_EXTENDING 128
15#define PKT_ERROR(pkt, errmsg) do {	   \
16    cfpkt_priv(pkt)->erronous = true;	   \
17    skb_reset_tail_pointer(&pkt->skb);	   \
18    pr_warning("CAIF: " errmsg);\
19  } while (0)
20
21struct cfpktq {
22	struct sk_buff_head head;
23	atomic_t count;
24	/* Lock protects count updates */
25	spinlock_t lock;
26};
27
28/*
29 * net/caif/ is generic and does not
30 * understand SKB, so we do this typecast
31 */
32struct cfpkt {
33	struct sk_buff skb;
34};
35
36/* Private data inside SKB */
37struct cfpkt_priv_data {
38	struct dev_info dev_info;
39	bool erronous;
40};
41
42inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
43{
44	return (struct cfpkt_priv_data *) pkt->skb.cb;
45}
46
47inline bool is_erronous(struct cfpkt *pkt)
48{
49	return cfpkt_priv(pkt)->erronous;
50}
51
52inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
53{
54	return &pkt->skb;
55}
56
57inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
58{
59	return (struct cfpkt *) skb;
60}
61
62
63struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
64{
65	struct cfpkt *pkt = skb_to_pkt(nativepkt);
66	cfpkt_priv(pkt)->erronous = false;
67	return pkt;
68}
69EXPORT_SYMBOL(cfpkt_fromnative);
70
71void *cfpkt_tonative(struct cfpkt *pkt)
72{
73	return (void *) pkt;
74}
75EXPORT_SYMBOL(cfpkt_tonative);
76
77static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
78{
79	struct sk_buff *skb;
80
81	if (likely(in_interrupt()))
82		skb = alloc_skb(len + pfx, GFP_ATOMIC);
83	else
84		skb = alloc_skb(len + pfx, GFP_KERNEL);
85
86	if (unlikely(skb == NULL))
87		return NULL;
88
89	skb_reserve(skb, pfx);
90	return skb_to_pkt(skb);
91}
92
93inline struct cfpkt *cfpkt_create(u16 len)
94{
95	return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
96}
97EXPORT_SYMBOL(cfpkt_create);
98
99void cfpkt_destroy(struct cfpkt *pkt)
100{
101	struct sk_buff *skb = pkt_to_skb(pkt);
102	kfree_skb(skb);
103}
104EXPORT_SYMBOL(cfpkt_destroy);
105
106inline bool cfpkt_more(struct cfpkt *pkt)
107{
108	struct sk_buff *skb = pkt_to_skb(pkt);
109	return skb->len > 0;
110}
111EXPORT_SYMBOL(cfpkt_more);
112
113int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
114{
115	struct sk_buff *skb = pkt_to_skb(pkt);
116	if (skb_headlen(skb) >= len) {
117		memcpy(data, skb->data, len);
118		return 0;
119	}
120	return !cfpkt_extr_head(pkt, data, len) &&
121	    !cfpkt_add_head(pkt, data, len);
122}
123EXPORT_SYMBOL(cfpkt_peek_head);
124
125int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
126{
127	struct sk_buff *skb = pkt_to_skb(pkt);
128	u8 *from;
129	if (unlikely(is_erronous(pkt)))
130		return -EPROTO;
131
132	if (unlikely(len > skb->len)) {
133		PKT_ERROR(pkt, "cfpkt_extr_head read beyond end of packet\n");
134		return -EPROTO;
135	}
136
137	if (unlikely(len > skb_headlen(skb))) {
138		if (unlikely(skb_linearize(skb) != 0)) {
139			PKT_ERROR(pkt, "cfpkt_extr_head linearize failed\n");
140			return -EPROTO;
141		}
142	}
143	from = skb_pull(skb, len);
144	from -= len;
145	memcpy(data, from, len);
146	return 0;
147}
148EXPORT_SYMBOL(cfpkt_extr_head);
149
150int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
151{
152	struct sk_buff *skb = pkt_to_skb(pkt);
153	u8 *data = dta;
154	u8 *from;
155	if (unlikely(is_erronous(pkt)))
156		return -EPROTO;
157
158	if (unlikely(skb_linearize(skb) != 0)) {
159		PKT_ERROR(pkt, "cfpkt_extr_trail linearize failed\n");
160		return -EPROTO;
161	}
162	if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
163		PKT_ERROR(pkt, "cfpkt_extr_trail read beyond end of packet\n");
164		return -EPROTO;
165	}
166	from = skb_tail_pointer(skb) - len;
167	skb_trim(skb, skb->len - len);
168	memcpy(data, from, len);
169	return 0;
170}
171EXPORT_SYMBOL(cfpkt_extr_trail);
172
173int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
174{
175	return cfpkt_add_body(pkt, NULL, len);
176}
177EXPORT_SYMBOL(cfpkt_pad_trail);
178
179int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
180{
181	struct sk_buff *skb = pkt_to_skb(pkt);
182	struct sk_buff *lastskb;
183	u8 *to;
184	u16 addlen = 0;
185
186
187	if (unlikely(is_erronous(pkt)))
188		return -EPROTO;
189
190	lastskb = skb;
191
192	/* Check whether we need to add space at the tail */
193	if (unlikely(skb_tailroom(skb) < len)) {
194		if (likely(len < PKT_LEN_WHEN_EXTENDING))
195			addlen = PKT_LEN_WHEN_EXTENDING;
196		else
197			addlen = len;
198	}
199
200	/* Check whether we need to change the SKB before writing to the tail */
201	if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
202
203		/* Make sure data is writable */
204		if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
205			PKT_ERROR(pkt, "cfpkt_add_body: cow failed\n");
206			return -EPROTO;
207		}
208		/*
209		 * Is the SKB non-linear after skb_cow_data()? If so, we are
210		 * going to add data to the last SKB, so we need to adjust
211		 * lengths of the top SKB.
212		 */
213		if (lastskb != skb) {
214			pr_warning("CAIF: %s(): Packet is non-linear\n",
215				   __func__);
216			skb->len += len;
217			skb->data_len += len;
218		}
219	}
220
221	/* All set to put the last SKB and optionally write data there. */
222	to = skb_put(lastskb, len);
223	if (likely(data))
224		memcpy(to, data, len);
225	return 0;
226}
227EXPORT_SYMBOL(cfpkt_add_body);
228
229inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
230{
231	return cfpkt_add_body(pkt, &data, 1);
232}
233EXPORT_SYMBOL(cfpkt_addbdy);
234
235int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
236{
237	struct sk_buff *skb = pkt_to_skb(pkt);
238	struct sk_buff *lastskb;
239	u8 *to;
240	const u8 *data = data2;
241	int ret;
242	if (unlikely(is_erronous(pkt)))
243		return -EPROTO;
244	if (unlikely(skb_headroom(skb) < len)) {
245		PKT_ERROR(pkt, "cfpkt_add_head: no headroom\n");
246		return -EPROTO;
247	}
248
249	/* Make sure data is writable */
250	ret = skb_cow_data(skb, 0, &lastskb);
251	if (unlikely(ret < 0)) {
252		PKT_ERROR(pkt, "cfpkt_add_head: cow failed\n");
253		return ret;
254	}
255
256	to = skb_push(skb, len);
257	memcpy(to, data, len);
258	return 0;
259}
260EXPORT_SYMBOL(cfpkt_add_head);
261
262inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
263{
264	return cfpkt_add_body(pkt, data, len);
265}
266EXPORT_SYMBOL(cfpkt_add_trail);
267
268inline u16 cfpkt_getlen(struct cfpkt *pkt)
269{
270	struct sk_buff *skb = pkt_to_skb(pkt);
271	return skb->len;
272}
273EXPORT_SYMBOL(cfpkt_getlen);
274
275inline u16 cfpkt_iterate(struct cfpkt *pkt,
276			    u16 (*iter_func)(u16, void *, u16),
277			    u16 data)
278{
279	/*
280	 * Don't care about the performance hit of linearizing,
281	 * Checksum should not be used on high-speed interfaces anyway.
282	 */
283	if (unlikely(is_erronous(pkt)))
284		return -EPROTO;
285	if (unlikely(skb_linearize(&pkt->skb) != 0)) {
286		PKT_ERROR(pkt, "cfpkt_iterate: linearize failed\n");
287		return -EPROTO;
288	}
289	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
290}
291EXPORT_SYMBOL(cfpkt_iterate);
292
293int cfpkt_setlen(struct cfpkt *pkt, u16 len)
294{
295	struct sk_buff *skb = pkt_to_skb(pkt);
296
297
298	if (unlikely(is_erronous(pkt)))
299		return -EPROTO;
300
301	if (likely(len <= skb->len)) {
302		if (unlikely(skb->data_len))
303			___pskb_trim(skb, len);
304		else
305			skb_trim(skb, len);
306
307			return cfpkt_getlen(pkt);
308	}
309
310	/* Need to expand SKB */
311	if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
312		PKT_ERROR(pkt, "cfpkt_setlen: skb_pad_trail failed\n");
313
314	return cfpkt_getlen(pkt);
315}
316EXPORT_SYMBOL(cfpkt_setlen);
317
318struct cfpkt *cfpkt_create_uplink(const unsigned char *data, unsigned int len)
319{
320	struct cfpkt *pkt = cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
321	if (!pkt)
322		return NULL;
323	if (unlikely(data != NULL))
324		cfpkt_add_body(pkt, data, len);
325	return pkt;
326}
327EXPORT_SYMBOL(cfpkt_create_uplink);
328
329struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
330			     struct cfpkt *addpkt,
331			     u16 expectlen)
332{
333	struct sk_buff *dst = pkt_to_skb(dstpkt);
334	struct sk_buff *add = pkt_to_skb(addpkt);
335	u16 addlen = skb_headlen(add);
336	u16 neededtailspace;
337	struct sk_buff *tmp;
338	u16 dstlen;
339	u16 createlen;
340	if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
341		return dstpkt;
342	}
343	if (expectlen > addlen)
344		neededtailspace = expectlen;
345	else
346		neededtailspace = addlen;
347
348	if (dst->tail + neededtailspace > dst->end) {
349		/* Create a dumplicate of 'dst' with more tail space */
350		struct cfpkt *tmppkt;
351		dstlen = skb_headlen(dst);
352		createlen = dstlen + neededtailspace;
353		tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
354		if (tmppkt == NULL)
355			return NULL;
356		tmp = pkt_to_skb(tmppkt);
357		skb_set_tail_pointer(tmp, dstlen);
358		tmp->len = dstlen;
359		memcpy(tmp->data, dst->data, dstlen);
360		cfpkt_destroy(dstpkt);
361		dst = tmp;
362	}
363	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
364	cfpkt_destroy(addpkt);
365	dst->tail += addlen;
366	dst->len += addlen;
367	return skb_to_pkt(dst);
368}
369EXPORT_SYMBOL(cfpkt_append);
370
371struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
372{
373	struct sk_buff *skb2;
374	struct sk_buff *skb = pkt_to_skb(pkt);
375	struct cfpkt *tmppkt;
376	u8 *split = skb->data + pos;
377	u16 len2nd = skb_tail_pointer(skb) - split;
378
379	if (unlikely(is_erronous(pkt)))
380		return NULL;
381
382	if (skb->data + pos > skb_tail_pointer(skb)) {
383		PKT_ERROR(pkt,
384			  "cfpkt_split: trying to split beyond end of packet");
385		return NULL;
386	}
387
388	/* Create a new packet for the second part of the data */
389	tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
390				  PKT_PREFIX);
391	if (tmppkt == NULL)
392		return NULL;
393	skb2 = pkt_to_skb(tmppkt);
394
395
396	if (skb2 == NULL)
397		return NULL;
398
399	/* Reduce the length of the original packet */
400	skb_set_tail_pointer(skb, pos);
401	skb->len = pos;
402
403	memcpy(skb2->data, split, len2nd);
404	skb2->tail += len2nd;
405	skb2->len += len2nd;
406	return skb_to_pkt(skb2);
407}
408EXPORT_SYMBOL(cfpkt_split);
409
410char *cfpkt_log_pkt(struct cfpkt *pkt, char *buf, int buflen)
411{
412	struct sk_buff *skb = pkt_to_skb(pkt);
413	char *p = buf;
414	int i;
415
416	/*
417	 * Sanity check buffer length, it needs to be at least as large as
418	 * the header info: ~=50+ bytes
419	 */
420	if (buflen < 50)
421		return NULL;
422
423	snprintf(buf, buflen, "%s: pkt:%p len:%ld(%ld+%ld) {%ld,%ld} data: [",
424		is_erronous(pkt) ? "ERRONOUS-SKB" :
425		 (skb->data_len != 0 ? "COMPLEX-SKB" : "SKB"),
426		 skb,
427		 (long) skb->len,
428		 (long) (skb_tail_pointer(skb) - skb->data),
429		 (long) skb->data_len,
430		 (long) (skb->data - skb->head),
431		 (long) (skb_tail_pointer(skb) - skb->head));
432	p = buf + strlen(buf);
433
434	for (i = 0; i < skb_tail_pointer(skb) - skb->data && i < 300; i++) {
435		if (p > buf + buflen - 10) {
436			sprintf(p, "...");
437			p = buf + strlen(buf);
438			break;
439		}
440		sprintf(p, "%02x,", skb->data[i]);
441		p = buf + strlen(buf);
442	}
443	sprintf(p, "]\n");
444	return buf;
445}
446EXPORT_SYMBOL(cfpkt_log_pkt);
447
448int cfpkt_raw_append(struct cfpkt *pkt, void **buf, unsigned int buflen)
449{
450	struct sk_buff *skb = pkt_to_skb(pkt);
451	struct sk_buff *lastskb;
452
453	caif_assert(buf != NULL);
454	if (unlikely(is_erronous(pkt)))
455		return -EPROTO;
456	/* Make sure SKB is writable */
457	if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
458		PKT_ERROR(pkt, "cfpkt_raw_append: skb_cow_data failed\n");
459		return -EPROTO;
460	}
461
462	if (unlikely(skb_linearize(skb) != 0)) {
463		PKT_ERROR(pkt, "cfpkt_raw_append: linearize failed\n");
464		return -EPROTO;
465	}
466
467	if (unlikely(skb_tailroom(skb) < buflen)) {
468		PKT_ERROR(pkt, "cfpkt_raw_append: buffer too short - failed\n");
469		return -EPROTO;
470	}
471
472	*buf = skb_put(skb, buflen);
473	return 1;
474}
475EXPORT_SYMBOL(cfpkt_raw_append);
476
477int cfpkt_raw_extract(struct cfpkt *pkt, void **buf, unsigned int buflen)
478{
479	struct sk_buff *skb = pkt_to_skb(pkt);
480
481	caif_assert(buf != NULL);
482	if (unlikely(is_erronous(pkt)))
483		return -EPROTO;
484
485	if (unlikely(buflen > skb->len)) {
486		PKT_ERROR(pkt, "cfpkt_raw_extract: buflen too large "
487				"- failed\n");
488		return -EPROTO;
489	}
490
491	if (unlikely(buflen > skb_headlen(skb))) {
492		if (unlikely(skb_linearize(skb) != 0)) {
493			PKT_ERROR(pkt, "cfpkt_raw_extract: linearize failed\n");
494			return -EPROTO;
495		}
496	}
497
498	*buf = skb->data;
499	skb_pull(skb, buflen);
500
501	return 1;
502}
503EXPORT_SYMBOL(cfpkt_raw_extract);
504
505inline bool cfpkt_erroneous(struct cfpkt *pkt)
506{
507	return cfpkt_priv(pkt)->erronous;
508}
509EXPORT_SYMBOL(cfpkt_erroneous);
510
511struct cfpktq *cfpktq_create(void)
512{
513	struct cfpktq *q = kmalloc(sizeof(struct cfpktq), GFP_ATOMIC);
514	if (!q)
515		return NULL;
516	skb_queue_head_init(&q->head);
517	atomic_set(&q->count, 0);
518	spin_lock_init(&q->lock);
519	return q;
520}
521EXPORT_SYMBOL(cfpktq_create);
522
523void cfpkt_queue(struct cfpktq *pktq, struct cfpkt *pkt, unsigned short prio)
524{
525	atomic_inc(&pktq->count);
526	spin_lock(&pktq->lock);
527	skb_queue_tail(&pktq->head, pkt_to_skb(pkt));
528	spin_unlock(&pktq->lock);
529
530}
531EXPORT_SYMBOL(cfpkt_queue);
532
533struct cfpkt *cfpkt_qpeek(struct cfpktq *pktq)
534{
535	struct cfpkt *tmp;
536	spin_lock(&pktq->lock);
537	tmp = skb_to_pkt(skb_peek(&pktq->head));
538	spin_unlock(&pktq->lock);
539	return tmp;
540}
541EXPORT_SYMBOL(cfpkt_qpeek);
542
543struct cfpkt *cfpkt_dequeue(struct cfpktq *pktq)
544{
545	struct cfpkt *pkt;
546	spin_lock(&pktq->lock);
547	pkt = skb_to_pkt(skb_dequeue(&pktq->head));
548	if (pkt) {
549		atomic_dec(&pktq->count);
550		caif_assert(atomic_read(&pktq->count) >= 0);
551	}
552	spin_unlock(&pktq->lock);
553	return pkt;
554}
555EXPORT_SYMBOL(cfpkt_dequeue);
556
557int cfpkt_qcount(struct cfpktq *pktq)
558{
559	return atomic_read(&pktq->count);
560}
561EXPORT_SYMBOL(cfpkt_qcount);
562
563struct cfpkt *cfpkt_clone_release(struct cfpkt *pkt)
564{
565	struct cfpkt *clone;
566	clone  = skb_to_pkt(skb_clone(pkt_to_skb(pkt), GFP_ATOMIC));
567	/* Free original packet. */
568	cfpkt_destroy(pkt);
569	if (!clone)
570		return NULL;
571	return clone;
572}
573EXPORT_SYMBOL(cfpkt_clone_release);
574
575struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
576{
577	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
578}
579EXPORT_SYMBOL(cfpkt_info);
580