Re: [Bugme-new] [Bug 15379] New: u32 classifier port range calculation error

[jamal <hadi@cyberus.ca>]

This is expected.
An incoming packet is masked with 0x1FE0 at offset 20 and the
value is compared to 6880. If they match, success.
So between 1-10000, you essentially have some starting at 6880. 
And then at a large number prolly around port 15000, you have
a few more. and the pattern repeats etc.

cheers,
jamal

On Wed, 2010-02-24 at 14:52 -0800, Andrew Morton wrote:
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
> 
> On Tue, 23 Feb 2010 20:56:09 GMT bugzilla-daemon@bugzilla.kernel.org wrote:
> 
> > http://bugzilla.kernel.org/show_bug.cgi?id=15379
> > 
> >            Summary: u32 classifier port range calculation error
> >            Product: Networking
> >            Version: 2.5
> >     Kernel Version: All (2.6.32 tested)
> >           Platform: All
> >         OS/Version: Linux
> >               Tree: Mainline
> >             Status: NEW
> >           Severity: normal
> >           Priority: P1
> >          Component: Other
> >         AssignedTo: acme@ghostprotocols.net
> >         ReportedBy: reinaldoc@gmail.com
> >         Regression: No
> > 
> > 
> > U32 classifier have a problem on mask calculation of IP port range value.
> > 
> > To reproduce the problem:
> > 
> > ##### MASK CALCULATION FOR PORT RANGE 6880->6911
> > 
> > echo "obase=16;(2^13)-32" | bc
> > 1FE0
> > 
> > Example:
> > 
> > ###### TC SAMPLE RULES
> > tc qdisc del dev eth0 root >/dev/null 2>&1
> > 
> > tc qdisc  add dev eth0 root handle 1: htb default 1100
> > tc class  add dev eth0 root classid 1:1000 htb rate 1000Mbit ceil 1000Mbit
> > tc class  add dev eth0 classid 1:1100 parent 1:1000 htb prio 0 rate 999Mbit
> > ceil 999Mbit
> > tc class  add dev eth0 classid 1:1200 parent 1:1000 htb prio 0 rate 1Mbit  
> > ceil 1Mbit
> > 
> > tc filter add dev eth0 protocol ip prio 1 parent 1: u32 flowid 1:1200 match ip
> > dport 6880 0x1FE0
> > 
> > ###### STATS CLEAN ** success 0
> > tc -s filter show dev eth0
> > filter parent 1: protocol ip pref 1 u32
> > filter parent 1: protocol ip pref 1 u32 fh 800: ht divisor 1
> > filter parent 1: protocol ip pref 1 u32 fh 800::800 order 2048 key ht 800 bkt 0
> > flowid 1:1200  (rule hit 116 success 0)
> >   match 00001ae0/00001fe0 at 20 (success 0 )
> > 
> > ###### SENDING PACKETS I
> > # nmap example.ufpa.br -p 1-10000
> > 
> > ###### STATS I ** success 32 (OK)
> > # tc -s filter show dev eth0
> > filter parent 1: protocol ip pref 1 u32
> > filter parent 1: protocol ip pref 1 u32 fh 800: ht divisor 1
> > filter parent 1: protocol ip pref 1 u32 fh 800::800 order 2048 key ht 800 bkt 0
> > flowid 1:1200  (rule hit 12676 success 32)
> >   match 00001ae0/00001fe0 at 20 (success 32 )
> > 
> > ###### SENDING PACKETS II
> > # nmap example.ufpa.br -p 10000-20000
> > 
> > ###### STATS II ** success 64 (ERROR) - should not match
> > 
> > # tc -s filter show dev eth0
> > filter parent 1: protocol ip pref 1 u32
> > filter parent 1: protocol ip pref 1 u32 fh 800: ht divisor 1
> > filter parent 1: protocol ip pref 1 u32 fh 800::800 order 2048 key ht 800 bkt 0
> > flowid 1:1200  (rule hit 25172 success 64)
> >   match 00001ae0/00001fe0 at 20 (success 64 )
> > 
> > ###### SENDING PACKETS III
> > # nmap example.ufpa.br -p 20000-30000
> > 
> > ###### STATS III ** success 96 (ERROR) - should not match
> > 
> > # tc -s filter show dev eth0
> > filter parent 1: protocol ip pref 1 u32
> > filter parent 1: protocol ip pref 1 u32 fh 800: ht divisor 1
> > filter parent 1: protocol ip pref 1 u32 fh 800::800 order 2048 key ht 800 bkt 0
> > flowid 1:1200  (rule hit 43131 success 96)
> >   match 00001ae0/00001fe0 at 20 (success 96 )
> > 
> > ### End
> 
> --
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