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;
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);
}
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;
}
/*
* 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_warn("Packet is non-linear\n");
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;
}
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;
}
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, "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);