diff options
| author | Oliver Hartkopp <socketcan@hartkopp.net> | 2013-01-17 18:43:39 +0100 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2013-01-26 16:59:01 +0100 |
| commit | 156c2bb9f88065c8da78814f98fde665a5cbb527 (patch) | |
| tree | ecd77a89c19ed0e1d420568f85769d7289ac3a37 /drivers/net/can | |
| parent | e2d5f2c7d66224c1a401ed1f797e467c02c025b8 (diff) | |
can: add private data space for CAN sk_buffs
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>
Diffstat (limited to 'drivers/net/can')
| -rw-r--r-- | drivers/net/can/dev.c | 8 | ||||
| -rw-r--r-- | drivers/net/can/slcan.c | 8 |
2 files changed, 14 insertions, 2 deletions
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 6abc6e59778e..59ada082a994 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -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)); diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c index adc3708d8829..e79a8d10e0fc 100644 --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -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); |