linux/net/caif/cfpkt_skbuff.c
sjur.brandeland@stericsson.com 7ad65bf68d caif: Add support for CAIF over CDC NCM USB interface
NCM 1.0 does not support anything but Ethernet framing, hence
CAIF payload will be put into Ethernet frames.

Discovery is based on fixed USB vendor 0x04cc (ST-Ericsson),
product-id 0x230f (NCM). In this variant only CAIF payload is sent over
the NCM interface.

The CAIF stack (cfusbl.c) will when USB interface register first check if
we got a CDC NCM USB interface with the right VID, PID.
It will then read the device's Ethernet address and create a 'template'
Ethernet TX header, using a broadcast address as the destination address,
and EthType 0x88b5 (802.1 Local Experimental - vendor specific).

A protocol handler for 0x88b5 is setup for reception of CAIF frames from
the CDC NCM USB interface.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-05 18:27:56 -05:00

397 lines
8.6 KiB
C

/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
* 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;
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);