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

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Message-Id: <1267068257.3973.865.camel@bigi>
Date:	Wed, 24 Feb 2010 22:24:17 -0500
From:	jamal <hadi@...erus.ca>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	netdev@...r.kernel.org, bugzilla-daemon@...zilla.kernel.org,
	bugme-daemon@...zilla.kernel.org, reinaldoc@...il.com
Subject: Re: [Bugme-new] [Bug 15379] New: u32 classifier port range
 calculation error


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@...zilla.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@...stprotocols.net
> >         ReportedBy: reinaldoc@...il.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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