On 11/21/2013 04:56 PM, Chang Xiangzhong wrote:
> Function sctp_check_transmitted(transport t, ...) would iterate all of
> transport->transmitted queue and looking for the highest __newly__ acked tsn.
> The original algorithm would depend on the order of the assoc->transport_list
> (in function sctp_outq_sack line 1215 - 1226). The result might not be the
> expected due to the order of the tranport_list.
>
> Solution: checking if the exising is smaller than the new one before assigning
>
> Signed-off-by: Chang Xiangzhong <changxiangzhong@xxxxxxxxx>
Good find. This has been around for since day 1. It doesn't so much
depend on the order of the transport list, but on the order the
transports been used. I agree it is a problem if chunks have been
distributed across multiple transports and a singe SACK acking them all.
Acked-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
-vlad
> ---
> net/sctp/outqueue.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index ef9e2bb..1b494fa 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -1397,7 +1397,8 @@ static void sctp_check_transmitted(struct sctp_outq *q,
> */
> if (!tchunk->tsn_gap_acked) {
> tchunk->tsn_gap_acked = 1;
> - *highest_new_tsn_in_sack = tsn;
> + if (TSN_lt(*highest_new_tsn_in_sack, tsn))
> + *highest_new_tsn_in_sack = tsn;
> bytes_acked += sctp_data_size(tchunk);
> if (!tchunk->transport)
> migrate_bytes += sctp_data_size(tchunk);
>
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