0ae89beb28
Self generated skbuffs in net/can/bcm.c are setting a skb->sk reference but
no explicit destructor which is enforced since Linux 3.11 with commit
376c7311bd (net: add a temporary sanity check in skb_orphan()).
This patch adds some helper functions to make sure that a destructor is
properly defined when a sock reference is assigned to a CAN related skb.
To create an unshared skb owned by the original sock a common helper function
has been introduced to replace open coded functions to create CAN echo skbs.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Andre Naujoks <nautsch2@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
/*
|
|
* linux/can/skb.h
|
|
*
|
|
* Definitions for the CAN network socket buffer
|
|
*
|
|
* Copyright (C) 2012 Oliver Hartkopp <socketcan@hartkopp.net>
|
|
*
|
|
*/
|
|
|
|
#ifndef CAN_SKB_H
|
|
#define CAN_SKB_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/can.h>
|
|
#include <net/sock.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];
|
|
};
|
|
|
|
static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
|
|
{
|
|
return (struct can_skb_priv *)(skb->head);
|
|
}
|
|
|
|
static inline void can_skb_reserve(struct sk_buff *skb)
|
|
{
|
|
skb_reserve(skb, sizeof(struct can_skb_priv));
|
|
}
|
|
|
|
static inline void can_skb_destructor(struct sk_buff *skb)
|
|
{
|
|
sock_put(skb->sk);
|
|
}
|
|
|
|
static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
|
|
{
|
|
if (sk) {
|
|
sock_hold(sk);
|
|
skb->destructor = can_skb_destructor;
|
|
skb->sk = sk;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* returns an unshared skb owned by the original sock to be echo'ed back
|
|
*/
|
|
static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
|
|
{
|
|
if (skb_shared(skb)) {
|
|
struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
|
|
|
|
if (likely(nskb)) {
|
|
can_skb_set_owner(nskb, skb->sk);
|
|
consume_skb(skb);
|
|
return nskb;
|
|
} else {
|
|
kfree_skb(skb);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* we can assume to have an unshared skb with proper owner */
|
|
return skb;
|
|
}
|
|
|
|
#endif /* CAN_SKB_H */
|