Re: [PATCH] nefilter: nfnetlink: add nfnetlink_set_err and use it in ctnetlink

[Patrick McHardy <kaber@trash.net>]

Pablo Neira Ayuso wrote:
> Patrick McHardy wrote:
>> Pablo Neira Ayuso wrote:
>>> This patch adds nfnetlink_set_err() to propagate the error to netlink
>>> broadcast listener in case of memory allocation errors in the
>>> message building.
>>> +void nfnetlink_set_err(u32 group, int error)
>>> +{
>>> +    netlink_set_err(nfnl, 0, group, error);
>>> +}
>>> +EXPORT_SYMBOL_GPL(nfnetlink_set_err);
>> Please make the pid argument controllable by the caller as well. This
>> is necessary to avoid double error notifications when an error occurs
>> in response to a user-request triggering notifications.
> 
> OK, I'll add it, but the pid passed as argument will be zero by now.
> Note that, in the current code, user-requests ignore notification
> errors, so there is no chance to get double error notifications.

I know. I have the same function in my nftables tree though (but
requiring the pid-argument), so we might as well add it in a
future-proof way.

> I have another patch here to propagate errors of user-requests that
> result in failing notifications, then the pid parameter in
> nfnetlink_set_err() will be useful. That patch also includes the use of
> NETLINK_BROADCAST_ERROR. I'll send you that patch soon.

Thanks.