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how to use compress modul in ppp process

DISCUSSION C.J 3 participants 7 messages Apr 24, 2008 – Apr 28, 2008 PPP protocol drivers and compressors

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C.J

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#0 lore raw

Hi list,
I got some troubles on ppp_mppe. After successful negotiation with parameter mppc-128bit encrypt, I cannot get decompressed package.

Between server and client, I got the comp_data package with wireshark also in my client I can get this package( which is not decompressed at all ).

I found ppp_mppe module decomp_init has been called successful. But why it couldn't work for me?

I only know that we need call ioctl(PPPIOCSCOMPRESS) to set compressor and call ccp_test which is set COMP flags. Both of them I've use in my client.

Any ideas?

Thx & Regards

--
cj

#1 lore raw
Quoted 2 lines · C.J

I got some troubles on ppp_mppe. After successful negotiation with parameter mppc-128bit encrypt ...

MPPC is patent burdened, and not very widely available. Are you quite sure that you have it available in your kernel (or kernel modules)?

#2 lore raw
In reply to C.J
Quoted 1 line · C.J

Hi Charlie Brady

Please do not reply to just me. Please keep any replies on the list (and preferably, only on the list).

Quoted 6 lines
Quoted 2 lines

MPPC is patent burdened, and not very widely available. Are you quite sure that you have it available in your kernel (or kernel modules)?

I knew that pppd can use ppp_mppe. On the mppe log there are some messages as below :
comp count xxx: xxx
decomp count xxx: xxx
So we can tell it works for pppd well.

I don't know that anything you have said indicates that MPPC is available. It rarely is.

author
#3 lore raw
In reply to C.J

Hi ,

Quoted 2 lines

I don't know that anything you have said indicates that MPPC is available. It rarely is.

Sorry for mine behavior. I thought it maybe the pppol2tp driver's bug(have not handle this case). Now I'll ask l2tp user about that.

--
c.j

#4 lore raw
In reply to C.J
Quoted 7 lines · C.J

Hi ,

Quoted 2 lines

I don't know that anything you have said indicates that MPPC is available. It rarely is.

Sorry for mine behavior. I thought it maybe the pppol2tp driver's bug(have not handle this case).

Why did you think that?

Quoted 1 line

Now I'll ask l2tp user about that.

I very much doubt that will be relevant.

l2tp is just an encapsulation layer which has nothing to do with MPPC.

Do you have a good reason for apparently ignoring my statement that MPPC is usually not supported by the ppp modules in the kernel? Are you quite sure that your kernel (or kernel modules) has been specifically patched to support MPPC? If not, you cannot use MPPC, not matter how you configure your client.

author
#5 lore raw
In reply to C.J

Hi,

Quoted 1 line

Why did you think that?

Since I got a strange package with protocol field 0xFD(not 0x00FD).
I've read ppp_generic.txt and got that the upper layer should pass packages to ppp_generic driver with two octets protocol field. So this should be finished on l2tp layer(channel preferably) or other kinds of channel.

Quoted 1 line

l2tp is just an encapsulation layer which has nothing to do with MPPC.

You are right.

Quoted 5 lines

Do you have a good reason for apparently ignoring my statement that MPPC is usually not supported by the ppp modules in the kernel? Are you quite sure that your kernel (or kernel modules) has been specifically patched to support MPPC? If not, you cannot use MPPC, not matter how you configure your client.

Really? But in my machine(which kernel is 2.6, Debian system) has ppp_mppe module but no any patch. Also has other compress module such as bsd_comp, deflate. Does this mean that kernel support it and I can use it?

Thanks so much for your kindly reply.
Regards.

--
c.j

#6 lore raw
In reply to C.J
Quoted 8 lines · C.J
Quoted 5 lines · Charlie

Do you have a good reason for apparently ignoring my statement that MPPC is usually not supported by the ppp modules in the kernel? Are you quite sure that your kernel (or kernel modules) has been specifically patched to support MPPC? If not, you cannot use MPPC, not matter how you configure your client.

Really? But in my machine(which kernel is 2.6, Debian system) has ppp_mppe module but no any patch.

Debian kernels do not have MPPC support, because of (a) kernel.org kernel does not have MPPC support, and (b) the patent issue.

The ppp_mppe module provides MPPE support, not MPPC support.

Quoted 1 line

Also has other compress module such as bsd_comp, deflate.

This is not relevant.

Quoted 1 line

Does this mean that kernel support it and I can use it?

No.

Signature · 3 lines
James Cameron                         http://quozl.netrek.org/
HP Open Source, Volunteer             http://opensource.hp.com/
PPTP Client Project, Release Engineer http://pptpclient.sourceforge.net/