Hi Krister,
Krister Johansen <k...@templeofstupid.com> writes:
> The ipvlan code already knows how to detect when a duplicate address is
> about to be assigned to an ipvlan device. However, that failure is not
> propogated outward and leads to a silent failure. This teaches the ip
> address addition functions how to report this error to the user
> applications so that a notifier chain failure during ip address addition
> will not appear to succeed when it actually has not.
>
> This can be especially useful if it is necessary to provision many
> ipvlans in containers. The provisioning software (or operator) can use
> this to detect situations where an ip address is unexpectedly in use.
>
> Signed-off-by: Krister Johansen <k...@templeofstupid.com>
> ---
...
> @@ -489,7 +490,12 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa,
> struct nlmsghdr *nlh,
> Notifier will trigger FIB update, so that
> listeners of netlink will know about new ifaddr */
> rtmsg_ifa(RTM_NEWADDR, ifa, nlh, portid);
> - blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);
> + ret = blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);
Why are you doing this assignment if you aren't using the result?
> + ret = notifier_to_errno(ret);
> + if (ret) {
> + __inet_del_ifa(in_dev, ifap, 1, NULL, portid);
> + return ret;
> + }
>
> return 0;
> }
<<snip>>
> @@ -1031,9 +1032,15 @@ ipv6_add_addr(struct inet6_dev *idev, const struct
> in6_addr *addr,
> out2:
> rcu_read_unlock_bh();
>
> - if (likely(err == 0))
> - inet6addr_notifier_call_chain(NETDEV_UP, ifa);
> - else {
> + if (likely(err == 0)) {
> + err = inet6addr_notifier_call_chain(NETDEV_UP, ifa);
Same here...
> + err = notifier_to_errno(err);
> + if (err) {
> + __ipv6_del_addr(ifa, false);
> + ifa = ERR_PTR(err);
> + return ifa;
> + }
> + } else {
> kfree(ifa);
> ifa = ERR_PTR(err);
> }
