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Miller" , Jakub Kicinski , linux-sctp@vger.kernel.org, network dev , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 25, 2020 at 9:10 PM Marcelo Ricardo Leitner wrote: > > On Mon, May 25, 2020 at 04:42:16PM +0800, Xin Long wrote: > > On Sat, May 23, 2020 at 8:04 PM Jonas Falkevik wrote: > > > > > > On Tue, May 19, 2020 at 10:42 PM Marcelo Ricardo Leitner > > > wrote: > > > > > > > > On Fri, May 15, 2020 at 10:30:29AM +0200, Jonas Falkevik wrote: > > > > > On Wed, May 13, 2020 at 11:32 PM Marcelo Ricardo Leitner > > > > > wrote: > > > > > > > > > > > > On Wed, May 13, 2020 at 10:11:05PM +0200, Jonas Falkevik wrote: > > > > > > > On Wed, May 13, 2020 at 6:01 PM Marcelo Ricardo Leitner > > > > > > > wrote: > > > > > > > > > > > > > > > > On Wed, May 13, 2020 at 04:52:16PM +0200, Jonas Falkevik wrote: > > > > > > > > > Do not generate SCTP_ADDR_{MADE_PRIM,ADDED} events for SCTP_FUTURE_ASSOC assocs. > > > > > > > > > > > > > > > > How did you get them? > > > > > > > > > > > > > > > > > > > > > > I think one case is when receiving INIT chunk in sctp_sf_do_5_1B_init(). > > > > > > > Here a closed association is created, sctp_make_temp_assoc(). > > > > > > > Which is later used when calling sctp_process_init(). > > > > > > > In sctp_process_init() one of the first things are to call > > > > > > > sctp_assoc_add_peer() > > > > > > > on the closed / temp assoc. > > > > > > > > > > > > > > sctp_assoc_add_peer() are generating the SCTP_ADDR_ADDED event on the socket > > > > > > > for the potentially new association. > > > > > > > > > > > > I see, thanks. The SCTP_FUTURE_ASSOC means something different. It is > > > > > > for setting/getting socket options that will be used for new asocs. In > > > > > > this case, it is just a coincidence that asoc_id is not set (but > > > > > > initialized to 0) and SCTP_FUTURE_ASSOC is also 0. > > > > > > > > > > yes, you are right, I overlooked that. > > > > > > > > > > > Moreso, if I didn't > > > > > > miss anything, it would block valid events, such as those from > > > > > > sctp_sf_do_5_1D_ce > > > > > > sctp_process_init > > > > > > because sctp_process_init will only call sctp_assoc_set_id() by its > > > > > > end. > > > > > > > > > > Do we want these events at this stage? > > > > > Since the association is a newly established one, have the peer address changed? > > > > > Should we enqueue these messages with sm commands instead? > > > > > And drop them if we don't have state SCTP_STATE_ESTABLISHED? > > > > > > > > > > > > > > > > > I can't see a good reason for generating any event on temp assocs. So > > > > > > I'm thinking the checks on this patch should be on whether the asoc is > > > > > > a temporary one instead. WDYT? > > > > > > > > > > > > > > > > Agree, we shouldn't rely on coincidence. > > > > > Either check temp instead or the above mentioned state? > > > > > > > > > > > Then, considering the socket is locked, both code points should be > > > > > > allocating the IDR earlier. It's expensive, yes (point being, it could > > > > > > be avoided in case of other failures), but it should be generating > > > > > > events with the right assoc id. Are you interested in pursuing this > > > > > > fix as well? > > > > > > > > > > Sure. > > > > > > > > > > If we check temp status instead, we would need to allocate IDR earlier, > > > > > as you mention. So that we send the notification with correct assoc id. > > > > > > > > > > But shouldn't the SCTP_COMM_UP, for a newly established association, be the > > > > > first notification event sent? > > > > > The SCTP_COMM_UP notification is enqueued later in sctp_sf_do_5_1D_ce(). > > > > > > > > The RFC doesn't mention any specific ordering for them, but it would > > > > make sense. Reading the FreeBSD code now (which I consider a reference > > > > implementation), it doesn't raise these notifications from > > > > INIT_ACK/COOKIE_ECHO at all. The only trigger for SCTP_ADDR_ADDED > > > > event is ASCONF ADD command itself. So these are extra in Linux, and > > > > I'm afraid we got to stick with them. > > > > > > > > Considering the error handling it already has, looks like the > > > > reordering is feasible and welcomed. I'm thinking the temp check and > > > > reordering is the best way forward here. > > > > > > > > Thoughts? Neil? Xin? The assoc_id change might be considered an UAPI > > > > breakage. > > > > > > Some order is mentioned in RFC 6458 Chapter 6.1.1. > > > > > > SCTP_COMM_UP: A new association is now ready, and data may be > > > exchanged with this peer. When an association has been > > > established successfully, this notification should be the > > > first one. > > Oh, nice finding. > > > If this is true, as SCTP_COMM_UP event is always followed by state changed > > to ESTABLISHED. So I'm thinking to NOT make addr events by checking the > > state: > > > > @@ -343,6 +343,9 @@ void sctp_ulpevent_nofity_peer_addr_change(struct > > sctp_transport *transport, > > struct sockaddr_storage addr; > > struct sctp_ulpevent *event; > > > > + if (asoc->state < SCTP_STATE_ESTABLISHED) > > + return; > > + > > memset(&addr, 0, sizeof(struct sockaddr_storage)); > > memcpy(&addr, &transport->ipaddr, transport->af_specific->sockaddr_len); > > With the above said, yep. Thanks. > > > > > It's not easy to completely do assoc_id change/event reordering/temp check. > > As: > > Temp check should be fine, but agree re the others. Anyhow, the above > will be good already. :-) Hi Jonas, What do you think? If you agree, can you please continue to go with it after testing? Thanks. > > > > > 1. sctp_assoc_add_peer() is called in quite a few places where assoc_id is > > not set. > > 2. it's almost impossible to move SCTP_ADDR_ADDED from sctp_assoc_add_peer() > > after SCTP_COMM_UP. > > > > > > > > I can make a patch with a check on temp and make COMM_UP event first. > > > Currently the COMM_UP event is enqueued via commands > > > while the SCTP_ADDR_ADDED event is enqueued directly. > > > > > > sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); > > > vs. > > > asoc->stream.si->enqueue_event(&asoc->ulpq, event); > > > > > > Do you want me to change to use commands instead of enqueing? > > > Or should we enqueue the COMM_UP event directly? > > > > > > -Jonas