[mirror_ubuntu-artful-kernel.git] / net / caif / cfpkt_skbuff.c

/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/hardirq.h>
#include <linux/export.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_warn(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;
};

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

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

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

static 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;

	skb = alloc_skb(len + pfx, GFP_ATOMIC);
	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);
}

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

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

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);
}

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, "read beyond end of packet\n");
		return -EPROTO;
	}

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

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

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, "cow failed\n");
			return -EPROTO;
		}
	}

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

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

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, "no headroom\n");
		return -EPROTO;
	}

	/* Make sure data is writable */
	ret = skb_cow_data(skb, 0, &lastskb);
	if (unlikely(ret < 0)) {
		PKT_ERROR(pkt, "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);
}

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

int 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, "linearize failed\n");
		return -EPROTO;
	}
	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
}

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, "skb_pad_trail failed\n");

	return cfpkt_getlen(pkt);
}

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);
}

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, "trying to split beyond end of packet\n");
		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;
	skb2->priority = skb->priority;
	return skb_to_pkt(skb2);
}

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

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

void cfpkt_set_prio(struct cfpkt *pkt, int prio)
{
	pkt_to_skb(pkt)->priority = prio;
}
EXPORT_SYMBOL(cfpkt_set_prio);
Commit	Line	Data
15c9ac0c SB	1	/*
15c9ac0c SB	2	* Copyright (C) ST-Ericsson AB 2010
26ee65e6	3	* Author: Sjur Brendeland
15c9ac0c SB	4	* License terms: GNU General Public License (GPL) version 2
	5	*/
	6
b31fa5ba JP	7	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
b31fa5ba JP	8
15c9ac0c SB	9	#include <linux/string.h>
	10	#include <linux/skbuff.h>
	11	#include <linux/hardirq.h>
bc3b2d7f	12	#include <linux/export.h>
15c9ac0c SB	13	#include <net/caif/cfpkt.h>
15c9ac0c SB	14
24e263ad	15	#define PKT_PREFIX 48
2aa40aef	16	#define PKT_POSTFIX 2
15c9ac0c	17	#define PKT_LEN_WHEN_EXTENDING 128
b31fa5ba JP	18	#define PKT_ERROR(pkt, errmsg) \
	19	do { \
	20	cfpkt_priv(pkt)->erronous = true; \
	21	skb_reset_tail_pointer(&pkt->skb); \
	22	pr_warn(errmsg); \
	23	} while (0)
15c9ac0c SB	24
	25	struct cfpktq {
	26	struct sk_buff_head head;
	27	atomic_t count;
	28	/* Lock protects count updates */
	29	spinlock_t lock;
	30	};
	31
	32	/*
	33	* net/caif/ is generic and does not
	34	* understand SKB, so we do this typecast
	35	*/
	36	struct cfpkt {
	37	struct sk_buff skb;
	38	};
	39
	40	/* Private data inside SKB */
	41	struct cfpkt_priv_data {
	42	struct dev_info dev_info;
	43	bool erronous;
	44	};
	45
73d6ac63	46	static inline struct cfpkt_priv_data cfpkt_priv(struct cfpkt pkt)
15c9ac0c SB	47	{
	48	return (struct cfpkt_priv_data *) pkt->skb.cb;
	49	}
	50
73d6ac63	51	static inline bool is_erronous(struct cfpkt *pkt)
15c9ac0c SB	52	{
	53	return cfpkt_priv(pkt)->erronous;
	54	}
	55
73d6ac63	56	static inline struct sk_buff pkt_to_skb(struct cfpkt pkt)
15c9ac0c SB	57	{
	58	return &pkt->skb;
	59	}
	60
73d6ac63	61	static inline struct cfpkt skb_to_pkt(struct sk_buff skb)
15c9ac0c SB	62	{
	63	return (struct cfpkt *) skb;
	64	}
	65
15c9ac0c SB	66	struct cfpkt cfpkt_fromnative(enum caif_direction dir, void nativepkt)
	67	{
	68	struct cfpkt *pkt = skb_to_pkt(nativepkt);
	69	cfpkt_priv(pkt)->erronous = false;
	70	return pkt;
	71	}
	72	EXPORT_SYMBOL(cfpkt_fromnative);
	73
	74	void cfpkt_tonative(struct cfpkt pkt)
	75	{
	76	return (void *) pkt;
	77	}
	78	EXPORT_SYMBOL(cfpkt_tonative);
	79
	80	static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
	81	{
	82	struct sk_buff *skb;
	83
f146e872	84	skb = alloc_skb(len + pfx, GFP_ATOMIC);
15c9ac0c SB	85	if (unlikely(skb == NULL))
	86	return NULL;
	87
	88	skb_reserve(skb, pfx);
	89	return skb_to_pkt(skb);
	90	}
	91
	92	inline struct cfpkt *cfpkt_create(u16 len)
	93	{
	94	return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
	95	}
15c9ac0c SB	96
	97	void cfpkt_destroy(struct cfpkt *pkt)
	98	{
	99	struct sk_buff *skb = pkt_to_skb(pkt);
	100	kfree_skb(skb);
	101	}
3f874adc	102
15c9ac0c SB	103	inline bool cfpkt_more(struct cfpkt *pkt)
	104	{
	105	struct sk_buff *skb = pkt_to_skb(pkt);
	106	return skb->len > 0;
	107	}
3f874adc	108
15c9ac0c SB	109	int cfpkt_peek_head(struct cfpkt pkt, void data, u16 len)
	110	{
	111	struct sk_buff *skb = pkt_to_skb(pkt);
	112	if (skb_headlen(skb) >= len) {
	113	memcpy(data, skb->data, len);
	114	return 0;
	115	}
	116	return !cfpkt_extr_head(pkt, data, len) &&
	117	!cfpkt_add_head(pkt, data, len);
	118	}
15c9ac0c SB	119
	120	int cfpkt_extr_head(struct cfpkt pkt, void data, u16 len)
	121	{
	122	struct sk_buff *skb = pkt_to_skb(pkt);
	123	u8 *from;
	124	if (unlikely(is_erronous(pkt)))
	125	return -EPROTO;
	126
	127	if (unlikely(len > skb->len)) {
b31fa5ba	128	PKT_ERROR(pkt, "read beyond end of packet\n");
15c9ac0c SB	129	return -EPROTO;
	130	}
	131
	132	if (unlikely(len > skb_headlen(skb))) {
	133	if (unlikely(skb_linearize(skb) != 0)) {
b31fa5ba	134	PKT_ERROR(pkt, "linearize failed\n");
15c9ac0c SB	135	return -EPROTO;
	136	}
	137	}
	138	from = skb_pull(skb, len);
	139	from -= len;
200c5a3b	140	if (data)
200c5a3b	141	memcpy(data, from, len);
15c9ac0c SB	142	return 0;
15c9ac0c SB	143	}
7ad65bf6	144	EXPORT_SYMBOL(cfpkt_extr_head);
15c9ac0c SB	145
	146	int cfpkt_extr_trail(struct cfpkt pkt, void dta, u16 len)
	147	{
	148	struct sk_buff *skb = pkt_to_skb(pkt);
	149	u8 *data = dta;
	150	u8 *from;
	151	if (unlikely(is_erronous(pkt)))
	152	return -EPROTO;
	153
	154	if (unlikely(skb_linearize(skb) != 0)) {
b31fa5ba	155	PKT_ERROR(pkt, "linearize failed\n");
15c9ac0c SB	156	return -EPROTO;
	157	}
	158	if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
b31fa5ba	159	PKT_ERROR(pkt, "read beyond end of packet\n");
15c9ac0c SB	160	return -EPROTO;
	161	}
	162	from = skb_tail_pointer(skb) - len;
	163	skb_trim(skb, skb->len - len);
	164	memcpy(data, from, len);
	165	return 0;
	166	}
3f874adc	167
15c9ac0c SB	168	int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
	169	{
	170	return cfpkt_add_body(pkt, NULL, len);
	171	}
3f874adc	172
15c9ac0c SB	173	int cfpkt_add_body(struct cfpkt pkt, const void data, u16 len)
	174	{
	175	struct sk_buff *skb = pkt_to_skb(pkt);
	176	struct sk_buff *lastskb;
	177	u8 *to;
	178	u16 addlen = 0;
	179
	180
	181	if (unlikely(is_erronous(pkt)))
	182	return -EPROTO;
	183
	184	lastskb = skb;
	185
	186	/* Check whether we need to add space at the tail */
	187	if (unlikely(skb_tailroom(skb) < len)) {
	188	if (likely(len < PKT_LEN_WHEN_EXTENDING))
	189	addlen = PKT_LEN_WHEN_EXTENDING;
	190	else
	191	addlen = len;
	192	}
	193
	194	/* Check whether we need to change the SKB before writing to the tail */
	195	if (unlikely((addlen > 0) \|\| skb_cloned(skb) \|\| skb_shared(skb))) {
	196
	197	/* Make sure data is writable */
	198	if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
b31fa5ba	199	PKT_ERROR(pkt, "cow failed\n");
15c9ac0c SB	200	return -EPROTO;
15c9ac0c SB	201	}
15c9ac0c SB	202	}
	203
	204	/* All set to put the last SKB and optionally write data there. */
253c6daa	205	to = pskb_put(skb, lastskb, len);
15c9ac0c SB	206	if (likely(data))
	207	memcpy(to, data, len);
	208	return 0;
	209	}
15c9ac0c SB	210
	211	inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
	212	{
	213	return cfpkt_add_body(pkt, &data, 1);
	214	}
15c9ac0c SB	215
	216	int cfpkt_add_head(struct cfpkt pkt, const void data2, u16 len)
	217	{
	218	struct sk_buff *skb = pkt_to_skb(pkt);
	219	struct sk_buff *lastskb;
	220	u8 *to;
	221	const u8 *data = data2;
638e628a	222	int ret;
15c9ac0c SB	223	if (unlikely(is_erronous(pkt)))
	224	return -EPROTO;
	225	if (unlikely(skb_headroom(skb) < len)) {
b31fa5ba	226	PKT_ERROR(pkt, "no headroom\n");
15c9ac0c SB	227	return -EPROTO;
	228	}
	229
	230	/* Make sure data is writable */
638e628a SB	231	ret = skb_cow_data(skb, 0, &lastskb);
638e628a SB	232	if (unlikely(ret < 0)) {
b31fa5ba	233	PKT_ERROR(pkt, "cow failed\n");
638e628a	234	return ret;
15c9ac0c SB	235	}
	236
	237	to = skb_push(skb, len);
	238	memcpy(to, data, len);
	239	return 0;
	240	}
7ad65bf6	241	EXPORT_SYMBOL(cfpkt_add_head);
15c9ac0c SB	242
	243	inline int cfpkt_add_trail(struct cfpkt pkt, const void data, u16 len)
	244	{
	245	return cfpkt_add_body(pkt, data, len);
	246	}
3f874adc	247
15c9ac0c SB	248	inline u16 cfpkt_getlen(struct cfpkt *pkt)
	249	{
	250	struct sk_buff *skb = pkt_to_skb(pkt);
	251	return skb->len;
	252	}
3f874adc	253
278f7b4f DC	254	int cfpkt_iterate(struct cfpkt *pkt,
	255	u16 (iter_func)(u16, void , u16),
	256	u16 data)
15c9ac0c SB	257	{
	258	/*
	259	* Don't care about the performance hit of linearizing,
	260	* Checksum should not be used on high-speed interfaces anyway.
	261	*/
	262	if (unlikely(is_erronous(pkt)))
	263	return -EPROTO;
	264	if (unlikely(skb_linearize(&pkt->skb) != 0)) {
b31fa5ba	265	PKT_ERROR(pkt, "linearize failed\n");
15c9ac0c SB	266	return -EPROTO;
	267	}
	268	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
	269	}
3f874adc	270
15c9ac0c SB	271	int cfpkt_setlen(struct cfpkt *pkt, u16 len)
	272	{
	273	struct sk_buff *skb = pkt_to_skb(pkt);
	274
	275
	276	if (unlikely(is_erronous(pkt)))
	277	return -EPROTO;
	278
	279	if (likely(len <= skb->len)) {
	280	if (unlikely(skb->data_len))
	281	___pskb_trim(skb, len);
	282	else
	283	skb_trim(skb, len);
	284
8e0cc8c3	285	return cfpkt_getlen(pkt);
15c9ac0c SB	286	}
	287
	288	/* Need to expand SKB */
	289	if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
b31fa5ba	290	PKT_ERROR(pkt, "skb_pad_trail failed\n");
15c9ac0c SB	291
	292	return cfpkt_getlen(pkt);
	293	}
15c9ac0c	294
15c9ac0c	295	struct cfpkt cfpkt_append(struct cfpkt dstpkt,
3bffc475 SMP	296	struct cfpkt *addpkt,
3bffc475 SMP	297	u16 expectlen)
15c9ac0c SB	298	{
	299	struct sk_buff *dst = pkt_to_skb(dstpkt);
	300	struct sk_buff *add = pkt_to_skb(addpkt);
	301	u16 addlen = skb_headlen(add);
	302	u16 neededtailspace;
	303	struct sk_buff *tmp;
	304	u16 dstlen;
	305	u16 createlen;
	306	if (unlikely(is_erronous(dstpkt) \|\| is_erronous(addpkt))) {
15c9ac0c SB	307	return dstpkt;
	308	}
	309	if (expectlen > addlen)
	310	neededtailspace = expectlen;
	311	else
	312	neededtailspace = addlen;
	313
	314	if (dst->tail + neededtailspace > dst->end) {
	315	/* Create a dumplicate of 'dst' with more tail space */
638e628a	316	struct cfpkt *tmppkt;
15c9ac0c SB	317	dstlen = skb_headlen(dst);
15c9ac0c SB	318	createlen = dstlen + neededtailspace;
638e628a SB	319	tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
638e628a SB	320	if (tmppkt == NULL)
15c9ac0c	321	return NULL;
638e628a	322	tmp = pkt_to_skb(tmppkt);
15c9ac0c SB	323	skb_set_tail_pointer(tmp, dstlen);
	324	tmp->len = dstlen;
	325	memcpy(tmp->data, dst->data, dstlen);
	326	cfpkt_destroy(dstpkt);
	327	dst = tmp;
	328	}
	329	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
	330	cfpkt_destroy(addpkt);
	331	dst->tail += addlen;
	332	dst->len += addlen;
	333	return skb_to_pkt(dst);
	334	}
15c9ac0c SB	335
	336	struct cfpkt cfpkt_split(struct cfpkt pkt, u16 pos)
	337	{
	338	struct sk_buff *skb2;
	339	struct sk_buff *skb = pkt_to_skb(pkt);
638e628a	340	struct cfpkt *tmppkt;
15c9ac0c SB	341	u8 *split = skb->data + pos;
	342	u16 len2nd = skb_tail_pointer(skb) - split;
	343
	344	if (unlikely(is_erronous(pkt)))
	345	return NULL;
	346
	347	if (skb->data + pos > skb_tail_pointer(skb)) {
b31fa5ba	348	PKT_ERROR(pkt, "trying to split beyond end of packet\n");
15c9ac0c SB	349	return NULL;
	350	}
	351
	352	/* Create a new packet for the second part of the data */
638e628a SB	353	tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
	354	PKT_PREFIX);
	355	if (tmppkt == NULL)
	356	return NULL;
	357	skb2 = pkt_to_skb(tmppkt);
	358
15c9ac0c SB	359
	360	if (skb2 == NULL)
	361	return NULL;
	362
	363	/* Reduce the length of the original packet */
	364	skb_set_tail_pointer(skb, pos);
	365	skb->len = pos;
	366
	367	memcpy(skb2->data, split, len2nd);
	368	skb2->tail += len2nd;
	369	skb2->len += len2nd;
44764812	370	skb2->priority = skb->priority;
15c9ac0c SB	371	return skb_to_pkt(skb2);
15c9ac0c SB	372	}
15c9ac0c	373
73d6ac63	374	bool cfpkt_erroneous(struct cfpkt *pkt)
15c9ac0c SB	375	{
	376	return cfpkt_priv(pkt)->erronous;
	377	}
15c9ac0c SB	378
	379	struct caif_payload_info cfpkt_info(struct cfpkt pkt)
	380	{
	381	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
	382	}
7ad65bf6	383	EXPORT_SYMBOL(cfpkt_info);
44764812 DT	384
	385	void cfpkt_set_prio(struct cfpkt *pkt, int prio)
	386	{
	387	pkt_to_skb(pkt)->priority = prio;
	388	}
	389	EXPORT_SYMBOL(cfpkt_set_prio);