Patrick McHardy wrote:
> Pavel Emelianov wrote:
>> +static int veth_newlink(struct net_device *dev,
>> + struct nlattr *tb[], struct nlattr *data[])
>> +{
>> + int err;
>> + struct net_device *peer;
>> + struct veth_priv *priv;
>> + char ifname[IFNAMSIZ];
>> +
>> + /*
>> + * prepare the devices info
>> + */
>> +
>> + if (tb[IFLA_ADDRESS] == NULL)
>> + random_ether_addr(dev->dev_addr);
>> +
>> + if (data != NULL && data[VETH_INFO_PEER] != NULL) {
>> + err = nla_parse_nested(tb, IFLA_INFO_MAX,
>> + data[VETH_INFO_PEER], ifla_policy);
>> + if (err < 0)
>> + return err;
>> + }
>
>
> Not having a peer should be an error, no?
No. That's the intention - if the user doesn't specify "peer" in the
command line then two _identical_ devices are created. Of course, if
he specifies one name - there'll be a collision, but one can say
"my_own_veth_number_%d" and everything will be ok. Or just use the
default name provided. E.g. "ip link add type veth" will send a packet
with data[VETH_INFO_PEER} == NULL, but this is OK! User just wants a
default tunnel and he will get it :)
Does this answer your second comment below?
>> +
>> + if (tb[IFLA_IFNAME])
>> + nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
>> + else
>> + snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
>
>
> Does this work? The other device is not registered at this time, so I
> think the allocated names could clash ..
>
> If it does work you could also perform name allocation in the
> rtnl_create_link function.
>
>
>> +
>> + peer = rtnl_create_link(ifname, &veth_link_ops, tb);
>> + if (IS_ERR(peer))
>> + return PTR_ERR(peer);
>> +
>> + if (tb[IFLA_ADDRESS] == NULL)
>> + random_ether_addr(peer->dev_addr);
>> +
>> + /*
>> + * register devices
>> + */
>> +
>> + err = register_netdevice(peer);
>> + if (err < 0)
>> + goto err_register_peer;
>> +
>> + err = register_netdevice(dev);
>> + if (err < 0)
>> + goto err_register_dev;
>> +
>> + /*
>> + * tie the deviced together
>> + */
>> +
>> + priv = netdev_priv(dev);
>> + priv->dev = dev;
>> + priv->peer = peer;
>> + list_add(&priv->list, &veth_list);
>> +
>> + priv = netdev_priv(peer);
>> + priv->dev = peer;
>> + priv->peer = dev;
>> + INIT_LIST_HEAD(&priv->list);
>> + return 0;
>> +
>> +err_register_dev:
>> + unregister_netdevice(peer);
>> + return err;
>> +
>> +err_register_peer:
>> + free_netdev(peer);
>> + return err;
>> +}
>
>> +static __exit void veth_exit(void)
>> +{
>> + struct veth_priv *priv, *next;
>> +
>> + rtnl_lock();
>> + __rtnl_link_unregister(&veth_link_ops);
>> +
>> + list_for_each_entry_safe(priv, next, &veth_list, list)
>> + veth_dellink(priv->dev);
>> + rtnl_unlock();
>
>
> Devices are unregistered automatically through the dellink function,
> rtnl_link_unregister(..) is enough.
OK. This looks like a minor and not-significant comment, so
do I need to resend the patch or David is OK to take it and
I will send an incremental one?
Thanks,
Pavel
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