From: Patrick McHardy <kaber@trash.net>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netdev@vger.kernel.org, davem@davemloft.net
Subject: Re: [PATCH] netlink: change nlmsg_notify() return value logic
Date: Wed, 25 Feb 2009 06:35:57 +0100 [thread overview]
Message-ID: <49A4D8BD.4090701@trash.net> (raw)
In-Reply-To: <20090225025502.4716.3568.stgit@Decadence>
Pablo Neira Ayuso wrote:
> This patch changes the return value of nlmsg_notify() as follows:
>
> If NETLINK_BROADCAST_ERROR is set by any of the listeners and
> an error in the delivery happened, return the broadcast error;
> else if there are no listeners apart from the socket that
> requested a change with the echo flag, return the result of the
> unicast notification. Thus, with this patch, the unicast
> notification is handled in the same way of a broadcast listener
> that has set the NETLINK_BROADCAST_ERROR socket flag.
Seems reasonable.
> This patch is useful in case that the caller of nlmsg_notify()
> wants to know the result of the delivery of a netlink notification
> (including the broadcast delivery) and take any action in case
> that the delivery failed. For example, ctnetlink can drop packets
> if the event delivery failed to provide reliable logging and
> state-synchronization at the cost of dropping packets.
>
> This patch also modifies the rtnetlink code to ignore the return
> value of rtnl_notify() in all callers. The function rtnl_notify()
> (before this patch) returned the error of the unicast notification
> which makes rtnl_set_sk_err() reports errors to all listeners. This
> is not of any help since the origin of the change (the socket that
> requested the echoing) notices the ENOBUFS error if the notification
> fails and should resync itself.
Also makes sense.
Acked-by: Patrick McHardy <kaber@trash.net>
next prev parent reply other threads:[~2009-02-25 5:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-25 2:55 [PATCH] netlink: change nlmsg_notify() return value logic Pablo Neira Ayuso
2009-02-25 5:35 ` Patrick McHardy [this message]
2009-02-25 7:18 ` David Miller
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