Date: Mon, 25 May 2009 10:16:00 +0100 From: John McLaughlin <jmclaughlin@tssg.org> To: freebsd-pf@freebsd.org Subject: Address family problems with ECN + ALTQ on IPv6 Message-ID: <4A1A61D0.9010108@tssg.org>
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Hi,
I'm trying to set up a testbed to play around with some ideas regarding
ECN. The hardware scenario involves having a Linux box (has to be Linux)
either side of a FreeBSD router. All addressing is IPv6 (also a requirement)
I've configured Pf really in a really simple fashion thus:
ext_if="xl0"
altq on $ext_if cbq bandwidth 1Mb tbrsize 4000 qlimit 5 queue { def }
queue def bandwidth 100% cbq(default red ecn)
and this works insofar as the bandwidth is limited as specified.
I use Netperf to generate traffic between the 2 endpoints through the
router, but no packet ever gets marked with CE - only dropped. Traffic
is always a TCP stream
I investigated further be embedding debug statements into altq_ecn.c,
and have discovered that the mark_ecn() function is failing at the line:
if (af != AF_INET && af != AF_INET6)
return (0);
Checking the value of af, it is *always* returned as 0 - I would expect
28 from looking at socket.h.
ECN usage between the two endpoints is negotiated successfully - using
Wireshark I can see this in the SYN/SYN ACK packet. Furthermore the
outgoing data packets are marked with the ECT(0) (10) codepoint, but the
router never signals congestion with the CE (11) codepoint as it always
fails the address family check
Am I missing some sysctl configuration somewhere or possibly a kernel
option, or is this a bug? The following are my kernel options:
# ALTQ support
device pf
device pflog
device pfsync
options ALTQ
options ALTQ_CBQ # Class Bases Queuing (CBQ)
options ALTQ_RED # Random Early Detection (RED)
options ALTQ_RIO # RED In/Out
options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC)
options ALTQ_PRIQ # Priority Queuing (PRIQ)
options ALTQ_NOPCC # Required for SMP build
Any help will be much appreciated!
Regards,
John McLaughlin
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