xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

can: add private data space for CAN sk_buffs

Browse Source 
The struct can_skb_priv is used to transport additional information along
with the stored struct can(fd)_frame that can not be contained in existing
struct sk_buff elements.

can_skb_priv is located in the skb headroom, which does not touch the existing
CAN sk_buff usage with skb->data and skb->len, so that even out-of-tree
CAN drivers can be used without changes.

Btw. out-of-tree CAN drivers without can_skb_priv in the sk_buff headroom
would not support features based on can_skb_priv.

The can_skb_priv->ifindex contains the first interface where the CAN frame
appeared on the local host. Unfortunately skb->skb_iif can not be used as this
value is overwritten in every netif_receive_skb() call.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp
2013-01-17 18:43:39 +01:00
committed by Marc Kleine-Budde
parent e2d5f2c7d6
commit 156c2bb9f8
5 changed files with 64 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/net/can/dev.c
View File

@@ -24,6 +24,7 @@
#include <linux/if_arp.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/skb.h>
#include <linux/can/netlink.h>
#include <linux/can/led.h>
#include <net/rtnetlink.h>
@@ -502,13 +503,18 @@ 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));
skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
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;
skb_reserve(skb, sizeof(struct can_skb_priv));
((struct can_skb_priv *)(skb->head))->ifindex = dev->ifindex;
*cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
memset(*cf, 0, sizeof(struct can_frame));

8
drivers/net/can/slcan.c
View File

@@ -55,6 +55,7 @@
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/can.h>
#include <linux/can/skb.h>
static __initconst const char banner[] =
KERN_INFO "slcan: serial line CAN interface driver\n";
@@ -184,7 +185,8 @@ static void slc_bump(struct slcan *sl)
cf.data[i] |= tmp;
}
skb = dev_alloc_skb(sizeof(struct can_frame));
skb = dev_alloc_skb(sizeof(struct can_frame) +
sizeof(struct can_skb_priv));
if (!skb)
return;
@@ -192,6 +194,10 @@ static void slc_bump(struct slcan *sl)
skb->protocol = htons(ETH_P_CAN);
skb->pkt_type = PACKET_BROADCAST;
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb_reserve(skb, sizeof(struct can_skb_priv));
((struct can_skb_priv *)(skb->head))->ifindex = sl->dev->ifindex;
memcpy(skb_put(skb, sizeof(struct can_frame)),
&cf, sizeof(struct can_frame));
netif_rx_ni(skb);