Got some help from a good friend and found out with some printk's that the following function fails
drivers/net/
tun.c :
static void tun_setup(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev); // dev->priv
skb_queue_head_init(&tun->readq);
init_waitqueue_head(&tun->read_wait);
tun->owner = -1;
tun->group = -1;
dev->open = tun_net_open;
dev->hard_start_xmit = tun_net_xmit;
dev->stop = tun_net_close;
dev->ethtool_ops = &tun_ethtool_ops;
dev->destructor = free_netdev;
}
tun = 0 after the netdev_priv(dev) call. (which actually is just a dev->priv call in netdevice.h.
Then we tried to find the place where priv get's initialized, which is in include/linux/
netdevice.h:
extern struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
void (*setup)(struct net_device *),
unsigned int queue_count);
#define alloc_netdev(sizeof_priv, name, setup) \
alloc_netdev_mq(sizeof_priv, name, setup, 1)
which is called with : alloc_netdev(80, "/dev/tun", tun_setup);
alloc_netdev_mq is in core/net/
dev.c:
struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
void (*setup)(struct net_device *), unsigned int queue_count)
{
void *p;
struct net_device *dev;
int alloc_size;
BUG_ON(strlen(name) >= sizeof(dev->name));
/* ensure 32-byte alignment of both the device and private area */
alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST +
(sizeof(struct net_device_subqueue) * (queue_count - 1))) &
~NETDEV_ALIGN_CONST;
alloc_size += sizeof_priv + NETDEV_ALIGN_CONST;
p = kzalloc(alloc_size, GFP_KERNEL);
if (!p) {
printk(KERN_ERR "alloc_netdev: Unable to allocate device.\n");
return NULL;
}
dev = (struct net_device *)
(((long)p + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST);
dev->padded = (char *)dev - (char *)p;
dev->nd_net = &init_net;
if (sizeof_priv) {
dev->priv = ((char *)dev +
((sizeof(struct net_device) +
(sizeof(struct net_device_subqueue) *
(queue_count - 1)) + NETDEV_ALIGN_CONST)
& ~NETDEV_ALIGN_CONST));
}
dev->egress_subqueue_count = queue_count;
dev->get_stats = internal_stats;
netpoll_netdev_init(dev);
setup(dev);
strcpy(dev->name, name);
return dev;
}
And that's where I'm stuck, it looks like it should work
I'm about to copy this code with constants into the tun class..
For referencing:
struct tun_struct {
struct list_head list;
unsigned long flags;
int attached;
uid_t owner;
gid_t group;
wait_queue_head_t read_wait;
struct sk_buff_head readq;
struct net_device *dev;
struct fasync_struct *fasync;
unsigned long if_flags;
u8 dev_addr[ETH_ALEN];
u32 chr_filter[2];
u32 net_filter[2];
#ifdef TUN_DEBUG
int debug;
#endif
};
