diff options
| author | Oliver Hartkopp <socketcan@hartkopp.net> | 2013-01-17 21:43:39 +0400 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2013-01-26 19:59:01 +0400 |
| commit | 156c2bb9f88065c8da78814f98fde665a5cbb527 (patch) | |
| tree | ecd77a89c19ed0e1d420568f85769d7289ac3a37 /net/can/bcm.c | |
| parent | e2d5f2c7d66224c1a401ed1f797e467c02c025b8 (diff) | |
| download | linux-156c2bb9f88065c8da78814f98fde665a5cbb527.tar.xz | |
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 'net/can/bcm.c')
| -rw-r--r-- | net/can/bcm.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c index 969b7cdff59d..ccc27b9e8384 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -54,6 +54,7 @@ #include <linux/skbuff.h> #include <linux/can.h> #include <linux/can/core.h> +#include <linux/can/skb.h> #include <linux/can/bcm.h> #include <linux/slab.h> #include <net/sock.h> @@ -256,10 +257,13 @@ static void bcm_can_tx(struct bcm_op *op) return; } - skb = alloc_skb(CFSIZ, gfp_any()); + skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), gfp_any()); if (!skb) goto out; + skb_reserve(skb, sizeof(struct can_skb_priv)); + ((struct can_skb_priv *)(skb->head))->ifindex = dev->ifindex; + memcpy(skb_put(skb, CFSIZ), cf, CFSIZ); /* send with loopback */ @@ -1199,11 +1203,12 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk) if (!ifindex) return -ENODEV; - skb = alloc_skb(CFSIZ, GFP_KERNEL); - + skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), GFP_KERNEL); if (!skb) return -ENOMEM; + skb_reserve(skb, sizeof(struct can_skb_priv)); + err = memcpy_fromiovec(skb_put(skb, CFSIZ), msg->msg_iov, CFSIZ); if (err < 0) { kfree_skb(skb); @@ -1216,6 +1221,7 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk) return -ENODEV; } + ((struct can_skb_priv *)(skb->head))->ifindex = dev->ifindex; skb->dev = dev; skb->sk = sk; err = can_send(skb, 1); /* send with loopback */ |