From: Chang Xiangzhong <changxiangzhong@gmail.com>
Date: Thu, 21 Nov 2013 21:56:28 +0000 (+0100)
Subject: net: sctp: find the correct highest_new_tsn in sack
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d6c416148545bd99d3cc05e672460168245cc156;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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 94df75877869..abb6db008df1 100644
--- 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);