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Message-ID: <CADvbK_cYTNupYG4rLPcTz8J7HK5DajcW=UfqNT64-vJi+9yx4w@mail.gmail.com>
Date: Tue, 22 Oct 2019 19:13:30 +0800
From: Xin Long <lucien.xin@...il.com>
To: David Laight <David.Laight@...lab.com>
Cc: network dev <netdev@...r.kernel.org>,
"linux-sctp@...r.kernel.org" <linux-sctp@...r.kernel.org>,
Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
Neil Horman <nhorman@...driver.com>,
"davem@...emloft.net" <davem@...emloft.net>
Subject: Re: [PATCHv3 net-next 1/5] sctp: add SCTP_ADDR_POTENTIALLY_FAILED notification
Hi, David L.
I will repost if you don't have any other dissent.
Thanks for your nice review.
On Sat, Oct 19, 2019 at 4:55 PM Xin Long <lucien.xin@...il.com> wrote:
>
> On Fri, Oct 18, 2019 at 11:56 PM David Laight <David.Laight@...lab.com> wrote:
> >
> > I've found v3 :-)
> ah okay. sorry.
>
> > But it isn't that much better than v2.
> >
> > From: Xin Long
> > > Sent: 14 October 2019 07:15
> > > SCTP Quick failover draft section 5.1, point 5 has been removed
> > > from rfc7829. Instead, "the sender SHOULD (i) notify the Upper
> > > Layer Protocol (ULP) about this state transition", as said in
> > > section 3.2, point 8.
> > >
> > > So this patch is to add SCTP_ADDR_POTENTIALLY_FAILED, defined
> > > in section 7.1, "which is reported if the affected address
> > > becomes PF". Also remove transport cwnd's update when moving
> > > from PF back to ACTIVE , which is no longer in rfc7829 either.
> > >
> > > v1->v2:
> > > - no change
> > > v2->v3:
> > > - define SCTP_ADDR_PF SCTP_ADDR_POTENTIALLY_FAILED
> > >
> > > Signed-off-by: Xin Long <lucien.xin@...il.com>
> > > ---
> > > include/uapi/linux/sctp.h | 2 ++
> > > net/sctp/associola.c | 17 ++++-------------
> > > 2 files changed, 6 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
> > > index 6bce7f9..f4ab7bb 100644
> > > --- a/include/uapi/linux/sctp.h
> > > +++ b/include/uapi/linux/sctp.h
> > > @@ -410,6 +410,8 @@ enum sctp_spc_state {
> > > SCTP_ADDR_ADDED,
> > > SCTP_ADDR_MADE_PRIM,
> > > SCTP_ADDR_CONFIRMED,
> > > + SCTP_ADDR_POTENTIALLY_FAILED,
> > > +#define SCTP_ADDR_PF SCTP_ADDR_POTENTIALLY_FAILED
> > > };
> > >
> > >
> > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c
> > > index 1ba893b..4f9efba 100644
> > > --- a/net/sctp/associola.c
> > > +++ b/net/sctp/associola.c
> > > @@ -801,14 +801,6 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
> > > spc_state = SCTP_ADDR_CONFIRMED;
> > > else
> > > spc_state = SCTP_ADDR_AVAILABLE;
> > > - /* Don't inform ULP about transition from PF to
> > > - * active state and set cwnd to 1 MTU, see SCTP
> > > - * Quick failover draft section 5.1, point 5
> > > - */
> > > - if (transport->state == SCTP_PF) {
> > > - ulp_notify = false;
> > > - transport->cwnd = asoc->pathmtu;
> > > - }
> >
> > This is wrong.
> > If the old state is PF and the application hasn't exposed PF the event should be
> > ignored.
> yeps, in Patch 2/5:
> + if (transport->state == SCTP_PF &&
> + asoc->pf_expose != SCTP_PF_EXPOSE_ENABLE)
> + ulp_notify = false;
> + else if (transport->state == SCTP_UNCONFIRMED &&
> + error == SCTP_HEARTBEAT_SUCCESS)
> spc_state = SCTP_ADDR_CONFIRMED;
> else
> spc_state = SCTP_ADDR_AVAILABLE;
>
> >
> > > transport->state = SCTP_ACTIVE;
> > > break;
> > >
> > > @@ -817,19 +809,18 @@ void sctp_assoc_control_transport(struct sctp_association *asoc,
> > > * to inactive state. Also, release the cached route since
> > > * there may be a better route next time.
> > > */
> > > - if (transport->state != SCTP_UNCONFIRMED)
> > > + if (transport->state != SCTP_UNCONFIRMED) {
> > > transport->state = SCTP_INACTIVE;
> > > - else {
> > > + spc_state = SCTP_ADDR_UNREACHABLE;
> > > + } else {
> > > sctp_transport_dst_release(transport);
> > > ulp_notify = false;
> > > }
> > > -
> > > - spc_state = SCTP_ADDR_UNREACHABLE;
> > > break;
> > >
> > > case SCTP_TRANSPORT_PF:
> > > transport->state = SCTP_PF;
> > > - ulp_notify = false;
> >
> > Again the event should be supressed if PF isn't exposed.
> it will be suppressed after Patch 2/5:
> + if (asoc->pf_expose != SCTP_PF_EXPOSE_ENABLE)
> + ulp_notify = false;
> + else
> + spc_state = SCTP_ADDR_POTENTIALLY_FAILED;
> break;
>
> >
> > > + spc_state = SCTP_ADDR_POTENTIALLY_FAILED;
> > > break;
> > >
> > > default:
> > > --
> > > 2.1.0
> >
> > I also haven't spotted where the test that the application has actually enabled
> > state transition events is in the code.
> all events will be created, but dropped in sctp_ulpq_tail_event() when trying
> to deliver up:
>
> /* Check if the user wishes to receive this event. */
> if (!sctp_ulpevent_is_enabled(event, ulpq->asoc->subscribe))
> goto out_free;
>
> > I'd have thought it would be anything is built and allocated.
> >
> > David
> >
> > -
> > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> > Registration No: 1397386 (Wales)
> >
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