From 07b4d6a1749422fa1e054f3c2aba444acdba39e8 Mon Sep 17 00:00:00 2001
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Fri, 18 Mar 2016 18:39:18 -0300
Subject: [PATCH] sctp: do not update a_rwnd if we are not issuing a sack
The SACK can be lost pretty much elsewhere, but if its allocation fail,
we know we are not sending it, so it is better to revert a_rwnd to its
previous value as this may give it a chance to issue a window update
later.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/sctp/sm_sideeffect.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 3c22c41a2bc2..7fe56d0acabf 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -215,10 +215,14 @@ static int sctp_gen_sack(struct sctp_association *asoc, int force,
sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
} else {
+ __u32 old_a_rwnd = asoc->a_rwnd;
+
asoc->a_rwnd = asoc->rwnd;
sack = sctp_make_sack(asoc);
- if (!sack)
+ if (!sack) {
+ asoc->a_rwnd = old_a_rwnd;
goto nomem;
+ }
asoc->peer.sack_needed = 0;
asoc->peer.sack_cnt = 0;