On Wed, Jan 27, 2021 at 6:32 AM Wenzel, Marco <marco.wen...@a-eberle.de> wrote:
>
> Hi,
>
> we have figured out an issue with the current PRP driver when trying to
> communicate with Cisco IE 2000 industrial Ethernet switches in Redbox mode.
> The Cisco always resets the HSR/PRP sequence counter to "1" at low traffic
> (<= 1 frame in 400 ms). It can be reproduced by a simple ICMP echo request
> with 1 s interval between a Linux box running with PRP and a VDAN behind the
> Cisco Redbox. The Linux box then always receives frames with sequence counter
> "1" and drops them. The behavior is not configurable at the Cisco Redbox.
>
> I fixed it by ignoring sequence counters with value "1" at the sequence
> counter check in hsr_register_frame_out ():
>
> diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
> index 5c97de459905..630c238e81f0 100644
> --- a/net/hsr/hsr_framereg.c
> +++ b/net/hsr/hsr_framereg.c
> @@ -411,7 +411,7 @@ void hsr_register_frame_in(struct hsr_node *node, struct
> hsr_port *port,
> int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
> u16 sequence_nr)
> {
> - if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]))
> + if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]) &&
> (sequence_nr != 1))
> return 1;
>
> node->seq_out[port->type] = sequence_nr;
>
>
> Do you think this could be a solution? Should this patch be officially
> applied in order to avoid other users running into these communication issues?
This isn't the correct way to solve the problem. IEC 62439-3 defines
EntryForgetTime as "Time after which an entry is removed from the
duplicate table" with a value of 400ms and states devices should
usually be configured to keep entries in the table for a much shorter
time. hsr_framereg.c needs to be reworked to handle this according to
the specification.
>
> Thanks
> Marco Wenzel
Regards,
George McCollister
