can: provide library functions for skb allocation
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>
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 39b99f5..c3db111 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -366,17 +366,12 @@
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 @@
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
*/