Messages in this thread | | | Date | Tue, 20 Mar 2018 18:11:49 +0200 | From | Liran Alon <> | Subject | Re: [PATCH] net: dev_forward_skb(): Scrub packet's per-netns info only when crossing netns |
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On 20/03/18 18:00, David Miller wrote: > From: Liran Alon <LIRAN.ALON@ORACLE.COM> > Date: Tue, 20 Mar 2018 17:34:38 +0200 > >> I personally don't understand why we should maintain >> backwards-comparability to this behaviour. > > The reason is because not breaking things is a cornerstone of Linux > kernel development. > >> This feature is not documented to user-mode and I don't see why it >> is legit for the user to rely on it. > > Whether it is documented or not is irrelevant. A lot of our > interfaces and behaviors are not documented or poorly documented > at best. > >> In addition, even if we do want to maintain backwards-comparability to >> this behaviour, I think it is enough to have an opt-in flag in >> /proc/sys/net/core/ that when set to 1 will activate the fix in >> dev_forward_skb() provided by this patch. That would also be a very >> simple change to the patch provided here. > > Making it opt-in makes it more palatable, that's for sure. >
1. Do we want to make a flag for every bug that is user-space visible? I think there is place for consideration on a per-case basis. I still don't see how a user can utilize this behaviour. He is basically loosing information (skb->mark) without this patch.
2. Having said that, I don't mind changing patch to maintain backwards compatibility here. However, there was also a discussion here on where the flag should sit. I think that a global /proc/sys/net/core/ flag should be enough. Do you agree it's sufficient for now?
Thanks, -Liran
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