On Thu, Oct 10, 2019 at 12:18 AM Neil Horman [off-list ref] wrote:

On Tue, Oct 08, 2019 at 11:28:32PM +0800, Xin Long wrote:

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On Tue, Oct 8, 2019 at 9:02 PM David Laight [off-list ref] wrote:

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From: Xin Long

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Sent: 08 October 2019 12:25

This is a sockopt defined in section 7.3 of rfc7829: "Exposing
the Potentially Failed Path State", by which users can change
pf_expose per sock and asoc.

If I read these patches correctly the default for this sockopt in 'enabled'.
Doesn't this mean that old application binaries will receive notifications
that they aren't expecting?

I'd have thought that applications would be required to enable it.

If we do that, sctp_getsockopt_peer_addr_info() in patch 2/5 breaks.

I don't think we can safely do either of these things.  Older
applications still need to behave as they did prior to the introduction
of this notification, and we shouldn't allow unexpected notifications to
be sent.

Hi, Neil

I think about again, and also talked with QE, we think to get unexpected
notifications shouldn't be a problem for user's applications.

RFC actually keeps adding new notifications, and a user shouldn't expect
the specific notifications coming in some exact orders. They should just
ignore it and wait until the ones they expect. I don't think some users
would abort its application when getting an unexpected notification.

We should NACK patchset v3 and go with v2. What do you think?

What if you added a check in get_peer_addr_info to only return -EACCESS
if pf_expose is 0 and the application isn't subscribed to the PF event?

Neil

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        David

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