SACK (and PF) wierdness

[Pawel Worach]

Hi,

I bumped into a wierd problem with SACK.

Basically my setup is.
192.168.1.10    .-crossover             192.168.1.200
ftp server fxp0<->wireless ap<-> ~~~ <->laptop wireless ath0

I run ftp from the laptop to the server.
This is what happens:
ftp> get zero
local: zero remote: zero
200 EPRT command successful.
150 Opening BINARY mode data connection for 'zero'.
    476 KB  299.53 KB/s
426 Data connection: Operation not permitted.
487424 bytes received in 00:01 (299.49 KB/s)

I started to look at tcpdump while this was happening and quickly
noticed that the connection got dropped by PF when SACK kicked in.

PF says:Nov 20 04:27:35 <kern.crit> darkstar kernel: pf: BAD state: TCP 
192.168.1.10:20
192.168.1.10:20 192.168.1.200:50640 [lo=3604799807 high=3604800103 win=33304 mod
ulator=0 wscale=1] [lo=4089843176 high=4089909784 win=33304 modulator=0 wscale=1
] 4:4 FPA seq=3604799807 ack=4089843176 len=296 ackskew=0 pkts=2497:1693 dir=out
,fwd
Nov 20 04:27:35 <kern.crit> darkstar kernel: pf: State failure on: 1       |
Nov 20 04:27:40 <kern.crit> darkstar kernel: pf: BAD state: TCP 192.168.1.10:20
192.168.1.10:20 192.168.1.200:58378 [lo=1373010668 high=1373010980 win=33304 mod
ulator=0 wscale=1] [lo=3742879382 high=3742945990 win=33304 modulator=0 wscale=1
] 4:4 A seq=1373010668 ack=3742879382 len=1448 ackskew=0 pkts=1266:851 dir=out,f
wd
Nov 20 04:27:40 <kern.crit> darkstar kernel: pf: State failure on: 1       |
Nov 20 04:27:40 <kern.crit> darkstar kernel: pf: BAD state: TCP 192.168.1.10:20
192.168.1.10:20 192.168.1.200:58378 [lo=1373010668 high=1373010980 win=33304 mod
ulator=0 wscale=1] [lo=3742879382 high=3742945990 win=33304 modulator=0 wscale=1
] 4:4 A seq=1373010668 ack=3742879382 len=1448 ackskew=0 pkts=1266:851 dir=out,f
wd

If I disable sack on the ftp server everything works fine.

I can reproduce this problem 100%, I have never managed to transfer more
than 3Mb via ftp when SACK is on, with it off I see no problems, 11Mbit
wireless at ~650Kb/s

Attached are three tcpdumps of the ftp data channel after a 'get /dev/zero'.
(I picked out the smallest ones, dropped after about 400kb of zeros)

related pf.conf rules, on ftp server:
pass out log quick on fxp0 inet proto tcp from fxp0 to any flags S/SA keep
  state queue (bulk, fast)
and on client:
pass in log quick inet proto tcp from any port 20 to <firewall> port >= 1024 
flags S/SA keep state

Any ideas? More info?

-- 
Pawel