Re: Linux SCTP associations failure handlig

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

Hi oaitamrane,

On Wed, Jul 06, 2022 at 01:19:20PM -0000, oaitamrane@users.sourceforge.net wrote:
> 
> 
> Dear Marcelo
> 
> I would like to know if there is a way after association failure (SCTP_COMM_LOST event treceived) to retrieve UNSENT to peers and UNACKNOWLEDGED by peers Data Chunks for retransmission over an alternate association?
> I am using RHEL8.4 and sockets are set in NON BLOCKING mode.
> I have set the sctp_event_subscribe structure as follows:
> 
>   memset(&sctp_events, 0, sizeof(sctp_events));
> 
>   sctp_events.sctp_data_io_event = 1;
>   sctp_events.sctp_association_event = 1;
>   sctp_events.sctp_address_event =  1;
>   sctp_events.sctp_peer_error_event = 1;
>   sctp_events.sctp_adaptation_layer_event = 1;
>   sctp_events.sctp_shutdown_event = 1;
>   sctp_events.sctp_partial_delivery_event = 1;
>   sctp_events.sctp_send_failure_event_event = 1;
> 
>   ret = setsockopt(sock_fd, IPPROTO_SCTP, SCTP_EVENTS,
> &sctp_events, sizeof(sctp_events));

My understanding is that you should be getting it via
sctp_send_failure_event_event above, detailed in rfc6458#section-6.1.11.

When SCTP tears down an association, it marks the chunks in outqueue
as failed in __sctp_outq_teardown(), which then sctp_datamsg_destroy()
ends up picking up and sending notifications to the application.

I didn't check this on RHEL 8.4, though, but I believe it has support
for this RFC as well. If you have the event as above, it should be
there.

> 
> Can you please tell me if you a member of the dev team who can help me.

+Cc linux-sctp here to have a broader reach. We don't really use
sourceforge anymore. :-)

Cheers,
Marcelo

> 
> Regards
> Omar AIT AMRANE
> 
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