From 156c2bb9f88065c8da78814f98fde665a5cbb527 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Thu, 17 Jan 2013 18:43:39 +0100 Subject: 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 Signed-off-by: Marc Kleine-Budde --- drivers/net/can/slcan.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/net/can/slcan.c') 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 #include #include +#include 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); -- cgit v1.2.3