net: sctp: find the correct highest_new_tsn in sack

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@gmail.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 94df7587786992fa0a6341caaed284beb1df42e0..abb6db008df16b60d8c2feb6f3bc43e995ec1d5f 100644 (file)
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1391,7 +1391,8 @@ 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);