Commit 4a2b9c37 authored Mar 15, 2011 by Dan Siemon Committed by David S. Miller Mar 15, 2011

net_sched: fix ip_tos2prio

ECN support incorrectly maps ECN BESTEFFORT packets to TC_PRIO_FILLER
(1) instead of TC_PRIO_BESTEFFORT (0)

This means ECN enabled flows are placed in pfifo_fast/prio low priority
band, giving ECN enabled flows [ECT(0) and CE codepoints] higher drop
probabilities.

This is rather unfortunate, given we would like ECN being more widely
used.

Ref : http://www.coverfire.com/archives/2011/03/13/pfifo_fast-and-ecn/



Signed-off-by: Dan Siemon <dan@coverfire.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dave Täht <d@taht.net>
Cc: Jonathan Morton <chromatix99@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 73137147

net/ipv4/route.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -204,7 +204,7 @@ static struct dst_ops ipv4_dst_ops = {

		const __u8 ip_tos2prio[16] = {
		TC_PRIO_BESTEFFORT,
		ECN_OR_COST(FILLER),
		ECN_OR_COST(BESTEFFORT),
		TC_PRIO_BESTEFFORT,
		ECN_OR_COST(BESTEFFORT),
		TC_PRIO_BULK,