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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
Download patch file Download diff file Expand all files Collapse all files

42
drivers/net/can/dev.c
View file

@ -366,17 +366,12 @@ void can_restart(unsigned long data)
can_flush_echo_skb(dev);
/* send restart message upstream */
skb = dev_alloc_skb(sizeof(struct can_frame));
skb = alloc_can_err_skb(dev, &cf);
if (skb == NULL) {
err = -ENOMEM;
goto restart;
}
skb->dev = dev;
skb->protocol = htons(ETH_P_CAN);
cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
memset(cf, 0, sizeof(struct can_frame));
cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
cf->can_dlc = CAN_ERR_DLC;
cf->can_id |= CAN_ERR_RESTARTED;
netif_rx(skb);
@ -449,6 +444,39 @@ static void can_setup(struct net_device *dev)
dev->features = NETIF_F_NO_CSUM;
}
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->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));
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_skb);
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;
(*cf)->can_id = CAN_ERR_FLAG;
(*cf)->can_dlc = CAN_ERR_DLC;
return skb;
}
EXPORT_SYMBOL_GPL(alloc_can_err_skb);
/*
* Allocate and setup space for the CAN network device
*/