can: add private data space for CAN sk_buffs
Subsystems (2)
Oliver Hartkopp
maintainerPATCH 1/4 can: add private data space for CAN sk_buffs
From a5c67ec58a44ce986bb6a927807a697021ce3926 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <[email protected]>
Date: Wed, 16 Jan 2013 21:53:06 +0100
Subject: [PATCH 1/4] 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 <[email protected]>
--- drivers/net/can/dev.c | 8 +++++++- drivers/net/can/slcan.c | 8 +++++++- include/linux/can/skb.h | 35 +++++++++++++++++++++++++++++++++++ net/can/bcm.c | 12 +++++++++--- net/can/raw.c | 8 ++++++-- 5 files changed, 64 insertions(+), 7 deletions(-) create mode 100644 include/linux/can/skb.h
drivers/net/can/dev.c +7 -1
@@ -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 ));
drivers/net/can/slcan.c +7 -1
@@ -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);
include/linux/can/skb.h new file +35 -0
@@ -0,0 +1,35 @@ +/* +* linux/can/skb.h +* +* Definitions for the CAN network socket buffer +* +* Copyright (C) 2012 Oliver Hartkopp <[email protected]> +* +*/ + +#ifndef CAN_SKB_H +#define CAN_SKB_H + +#include <linux/types.h> +#include <linux/can.h> + +/* +* 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. +* N.B. that this information must not be modified in cloned CAN sk_buffs. +* To modify the CAN frame content or the struct can_skb_priv content +* skb_copy() needs to be used instead of skb_clone(). +*/ + +/** +* struct can_skb_priv - private additional data inside CAN sk_buffs +* @ifindex: ifindex of the first interface the CAN frame appeared on +* @cf: align to the following CAN frame at skb->data +*/ +struct can_skb_priv { +int ifindex; +struct can_frame cf[0 ]; +}; + +#endif /* CAN_SKB_H */
net/can/bcm.c +9 -3
@@ -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 */
net/can/raw.c +6 -2
@@ -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;
Signature · 1 line
1.7.10.4