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can: provide library functions for skb allocation

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This patch makes the private functions alloc_can_skb() and
alloc_can_err_skb() of the at91_can driver public and adapts all
drivers to use these. While making the patch I realized, that
the skb's are *not* setup consistently. It's now done as shown
below:

  skb->protocol = htons(ETH_P_CAN);
  skb->pkt_type = PACKET_BROADCAST;
  skb->ip_summed = CHECKSUM_UNNECESSARY;
  *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
  memset(*cf, 0, sizeof(struct can_frame));

The frame is zeroed out to avoid uninitialized data to be passed to
user space. Some drivers or library code did not set "pkt_type" or
"ip_summed". Also,  "__constant_htons()" should not be used for
runtime invocations, as pointed out by David Miller.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wolfgang Grandegger
2009-10-20 00:08:01 -07:00
committed by David S. Miller
parent 0eae750e60
commit 7b6856a029
6 changed files with 47 additions and 76 deletions
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32
drivers/net/can/at91_can.c
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@@ -221,38 +221,6 @@ static inline void set_mb_mode(const struct at91_priv *priv, unsigned int mb,
set_mb_mode_prio(priv, mb, mode, 0);
}
static struct sk_buff *alloc_can_skb(struct net_device *dev,
struct can_frame **cf)
{
struct sk_buff *skb;
skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
if (unlikely(!skb))
return NULL;
skb->protocol = htons(ETH_P_CAN);
skb->ip_summed = CHECKSUM_UNNECESSARY;
*cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
return skb;
}
static struct sk_buff *alloc_can_err_skb(struct net_device *dev,
struct can_frame **cf)
{
struct sk_buff *skb;
skb = alloc_can_skb(dev, cf);
if (unlikely(!skb))
return NULL;
memset(*cf, 0, sizeof(struct can_frame));
(*cf)->can_id = CAN_ERR_FLAG;
(*cf)->can_dlc = CAN_ERR_DLC;
return skb;
}
/*
* Swtich transceiver on or off
*/