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authorOliver Hartkopp <socketcan@hartkopp.net>2013-01-17 18:43:39 +0100
committerMarc Kleine-Budde <mkl@pengutronix.de>2013-01-26 16:59:01 +0100
commit156c2bb9f88065c8da78814f98fde665a5cbb527 (patch)
treeecd77a89c19ed0e1d420568f85769d7289ac3a37 /net/can
parente2d5f2c7d66224c1a401ed1f797e467c02c025b8 (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 'net/can')
-rw-r--r--net/can/bcm.c12
-rw-r--r--net/can/raw.c8
2 files changed, 15 insertions, 5 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 */
diff --git a/net/can/raw.c b/net/can/raw.c
index 5b0e3e330d97..5d860e8dcc52 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -50,6 +50,7 @@
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
+#include <linux/can/skb.h>
#include <linux/can/raw.h>
#include <net/sock.h>
#include <net/net_namespace.h>
@@ -699,11 +700,14 @@ static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
if (!dev)
return -ENXIO;
- skb = sock_alloc_send_skb(sk, size, msg->msg_flags & MSG_DONTWAIT,
- &err);
+ skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
+ msg->msg_flags & MSG_DONTWAIT, &err);
if (!skb)
goto put_dev;
+ skb_reserve(skb, sizeof(struct can_skb_priv));
+ ((struct can_skb_priv *)(skb->head))->ifindex = dev->ifindex;
+
err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
if (err < 0)
goto free_skb;

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