isdn_lzscomp.o & kernels after 2.3.42

thunder7@xs4all.nl
Sat, 10 Jun 2000 10:34:54 +0200

I seem to remember 2.3.42 was the last kernel without the network
updates going in? It also works well with isdn_lzscomp.o when later
kernels (all 2.3.99prex, 2.4.0-test1-acx) don't. I don't see any changes
in isdn_bsdcomp.o (another isdn compression routine), and as a newbie,
I'd have thought that meant isdn_lzscomp.o shouldn't have to change
either.

Contact with isdn-developers learns me that they concentrate on the isdn
stuff, not the latest kernels. Now I did look in the source of
isdn_lzscomp.c and looked through the softnet-HOWTO, and there isn't a
single occurence of dev in isdn_lzscomp.c so I don't see what should be
changed.

Could somebody knowledgable about the inner workings of linux network
drivers look through it sometime and point at some obviously dangerous
constructs? It behaves well in 2.3.42 (SMP!) and it doesn't behave well
in later kernels, both SMP and non-SMP. Symptoms are lots of messages
like

Jun 8 21:44:28 middle kernel: lzsDecomp: rcvd seq# 51 exp seq# 50 (sync lost)
Jun 8 21:44:28 middle kernel: ippp: decomp wants reset with params
Jun 8 21:44:28 middle kernel: ippp_ccp: new trans for id 0 to be started
Jun 8 21:44:28 middle kernel: Sending CCP Frame:
Jun 8 21:44:28 middle kernel: [0/1].ccp-xmit[0]: ff 03 80 fd 0e 00 00 06 00 01
Jun 8 21:44:28 middle kernel: ippp: compressed frame discarded!
Jun 8 21:44:28 middle kernel: lzsDecomp: rcvd seq# 52 but missing ResetAck
Jun 8 21:44:28 middle kernel: ippp: decomp wants reset with params
Jun 8 21:44:28 middle kernel: ippp_ccp: reset trans still in progress for id 0
Jun 8 21:44:28 middle kernel: ippp: compressed frame discarded!
Jun 8 21:44:28 middle kernel: lzsDecomp: rcvd seq# 53 but missing ResetAck
Jun 8 21:44:28 middle kernel: ippp: decomp wants reset with params
Jun 8 21:44:28 middle kernel: ippp_ccp: reset trans still in progress for id 0
Jun 8 21:44:28 middle kernel: ippp: compressed frame discarded!
Jun 8 21:44:28 middle kernel: lzsDecomp: rcvd seq# 54 but missing ResetAck
Jun 8 21:44:28 middle kernel: ippp: decomp wants reset with params
Jun 8 21:44:28 middle kernel: ippp_ccp: reset trans still in progress for id 0
Jun 8 21:44:28 middle kernel: ippp: compressed frame discarded!
Jun 8 21:44:28 middle kernel: Received CCP frame from peer
Jun 8 21:44:28 middle kernel: [0/1].ccp-rcv[0]: 0f 00 00 06 00 01
Jun 8 21:44:28 middle kernel: Received ResetAck from peer
Jun 8 21:44:28 middle kernel: ippp_ccp: freeing state for id 0

This makes sure the actual network speed goes from about 12 Kb/s with
working compression down to about 3 with a faulty compression, where 7.4
Kb/s without compression is the normal speed...

I'm willing to test anything, but I'm out of my depth here.

The source code is available at
http://www.isdn4linux.de/cgi-bin/cvsweb.cgi in the isdn4k-utils/ipppcomp
directory.

Thanks,
Jurriaan (thunder7@xs4all.nl)

-- 
If Presidents don't do it to their wives, they do it to the country.
        Mel Brooks
GNU/Linux 2.3.42 SMP 4 users load av: 1.29 1.12 0.74


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