Оптимизация кода, нарушающего правила strict aliasing

/* include/linux/netlink.h */
....
#define NETLINK_CB(skb)         (*(struct netlink_skb_parms*)&((skb)->cb))
....
/**
 * nlmsg_multicast - multicast a netlink message
 * @sk: netlink socket to spread messages to
 * @skb: netlink message as socket buffer
 * @pid: own netlink pid to avoid sending to yourself
 * @group: multicast group id
 * @flags: allocation flags
 */
static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
                                  u32 pid, unsigned int group, gfp_t flags)
{
        int err;
 
        NETLINK_CB(skb).dst_group = group;
 
        err = netlink_broadcast(sk, skb, pid, group, flags);
        if (err > 0)
                err = 0;
 
        return err;
}

static struct netlink_skb_parms *to_netlink_skb_parms(struct sk_buff *skb) {
       struct netlink_skb_parms *tmp;
       memcpy(&tmp, &((skb)->cb), 48);
       return tmp;
}
 
#define NETLINK_CB(skb) to_netlink_skb_parms(skb)

In file included from /media/chrono/Other/Chrono_Kernel-1/lib/kobject_uevent.c:25:0:
/media/chrono/Other/Chrono_Kernel-1/include/linux/netlink.h: In function ‘nlmsg_multicast’:
/media/chrono/Other/Chrono_Kernel-1/include/linux/netlink.h:38:24: error: request for member ‘dst_group’ in something not a structure or union
         NETLINK_CB(skb).dst_group = group;

struct netlink_skb_parms {
    struct ucred        creds;      /* Skb credentials  */
    __u32           pid;
    __u32           dst_group;
};
 
struct sk_buff {
    .....
 
    /*
     * This is the control buffer. It is free to use for every
     * layer. Please put your private variables there. If you
     * want to keep them across layers you have to do a skb_clone()
     * first. This is owned by whoever has the skb queued ATM.
     */
    char            cb[48] __aligned(8);
 
    ....
};