From: Neil Horman <nhorman@tuxdriver.com>
To: Xin Long <lucien.xin@gmail.com>
Cc: David Laight <David.Laight@aculab.com>,
network dev <netdev@vger.kernel.org>,
"linux-sctp@vger.kernel.org" <linux-sctp@vger.kernel.org>,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
"davem@davemloft.net" <davem@davemloft.net>
Subject: Re: [PATCHv2 net-next 3/5] sctp: add SCTP_EXPOSE_POTENTIALLY_FAILED_STATE sockopt
Date: Fri, 11 Oct 2019 17:29:04 -0400 [thread overview]
Message-ID: <20191011212904.GB16269@hmswarspite.think-freely.org> (raw)
In-Reply-To: <CADvbK_eZcNd8Xy-q5SWS2CzD1SdMqzU05_mGkmh5-iLtOdRCCw@mail.gmail.com>
On Sat, Oct 12, 2019 at 12:25:27AM +0800, Xin Long wrote:
> On Fri, Oct 11, 2019 at 11:57 PM Xin Long <lucien.xin@gmail.com> wrote:
> >
> > On Thu, Oct 10, 2019 at 8:40 PM Neil Horman <nhorman@tuxdriver.com> wrote:
> > >
> > > On Thu, Oct 10, 2019 at 05:28:34PM +0800, Xin Long wrote:
> > > > On Thu, Oct 10, 2019 at 12:18 AM Neil Horman <nhorman@tuxdriver.com> wrote:
> > > > >
> > > > > On Tue, Oct 08, 2019 at 11:28:32PM +0800, Xin Long wrote:
> > > > > > On Tue, Oct 8, 2019 at 9:02 PM David Laight <David.Laight@aculab.com> wrote:
> > > > > > >
> > > > > > > From: Xin Long
> > > > > > > > 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.
> > > > >
> > > > > 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?
> > > > We can't subscribe to PF event only, but all the SCTP_PEER_ADDR_CHANGE
> > > > events.
> > > >
> > > > Now I'm thinking both PF event and "return -EACCES" in get_peer_addr_info
> > > > are new, we should give 'expose' a default value that would disable both.
> > > > How do think if we set 'pf_expose = -1' by default. We send the pf event
> > > > only if (asoc->pf_expose > 0) in sctp_assoc_control_transport().
> > > >
> > > And if pf_expose = 0, we send the event, and return -EACCESS if we call
> > > the socket option and find a PF assoc? If so, yes, I think that makes
> > > sense.
> > pf_expose:
> > -1: compatible with old application (by default)
> > 0: not expose PF to user
> > 1: expose PF to user
> >
> > So it should be:
> > if pf_expose == -1: not send event, not return -EACCESS
> > if pf_expose == 0: not send event, return -EACCESS
> > if pf_expose > 0: sent event, not return -EACCESS
> >
> > makes sense?
> Oh, sorry, pf_expose is 1 bit only now in asoc/ep.
> Maybe we should use 2 bits, and values could be:
> 2: compatible with old application (by default)
> 0: not expose PF to user
> 1: expose PF to user
>
Yes, this version makes sense to me
Best
Neil
> >
> > >
> > > Neil
> > >
> > > > >
> > > > > Neil
> > > > >
> > > > > > >
> > > > > > > David
> > > > > > >
> > > > > > > -
> > > > > > > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> > > > > > > Registration No: 1397386 (Wales)
> > > > > > >
> > > > > >
> > > >
>
next prev parent reply other threads:[~2019-10-11 21:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 11:25 [PATCHv2 net-next 0/5] sctp: update from rfc7829 Xin Long
2019-10-08 11:25 ` [PATCHv2 net-next 1/5] sctp: add SCTP_ADDR_POTENTIALLY_FAILED notification Xin Long
2019-10-08 11:25 ` [PATCHv2 net-next 2/5] sctp: add pf_expose per netns and sock and asoc Xin Long
2019-10-08 11:25 ` [PATCHv2 net-next 3/5] sctp: add SCTP_EXPOSE_POTENTIALLY_FAILED_STATE sockopt Xin Long
2019-10-08 11:25 ` [PATCHv2 net-next 4/5] sctp: add support for Primary Path Switchover Xin Long
2019-10-08 11:25 ` [PATCHv2 net-next 5/5] sctp: add SCTP_PEER_ADDR_THLDS_V2 sockopt Xin Long
2019-10-08 13:02 ` [PATCHv2 net-next 3/5] sctp: add SCTP_EXPOSE_POTENTIALLY_FAILED_STATE sockopt David Laight
2019-10-08 15:28 ` Xin Long
2019-10-09 16:15 ` Neil Horman
2019-10-10 9:28 ` Xin Long
2019-10-10 12:40 ` Neil Horman
2019-10-11 15:57 ` Xin Long
2019-10-11 16:25 ` Xin Long
2019-10-11 21:29 ` Neil Horman [this message]
2019-10-14 8:36 ` Xin Long
2019-10-14 8:49 ` David Laight
2019-10-14 12:41 ` Neil Horman
2019-10-14 13:48 ` David Laight
2019-10-18 15:34 ` [PATCHv2 net-next 2/5] sctp: add pf_expose per netns and sock and asoc David Laight
2019-10-19 8:45 ` Xin Long
2019-10-22 11:29 ` David Laight
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