[pptp-server] SMP 2.2.14-5.0 Problem

[Charlie Brady]

On Mon, 23 Apr 2001, Michael St. Laurent wrote:

> OK, it appears that poptop working for some but not for others on SMP
> machines.  Perhaps we might find a pattern if we all reported to the list
> what versions and patches are being used and on what motherboard it is being
> run.
>
> I'll go first:
>
> Software:
> -----------------------------------------
> PoPToP - 1.1.2
> pppd - 2.3.11
> Redhat - 7.0
> Kernel - 2.2.17-14smp

PoPToP - 1.1.2
pppd - 2.4.0
e-smith 4.1.2, which is based on Redhat - 7.0
Kernel - 2.2.16-22smp

> Patches:
> -----------------------------------------
> MSChap-v2 & MPPE Encryption for 2.3.11
> Require-MPPE
> Strip MS Domain

An smbpasswd patch
My MPPE stateful patch

You can all find ppp-2.4.0-11.{src,i386}.rpm on our ftp site, which
builds/installs a suitably modified pppd and the supporting kernel
modules. Rather than have a name clash with the existing ppp.o, this rpm
includes a module named ppp-4mppe.o. In order for it to be loaded rather
than the RedHat ppp.o, one needs an entry "alias ppp ppp-4mppe" in
/etc/modules.conf.

Based on my experience developing this RPM, the most likely problems you
might have with SMP is getting the compile arguments just right when
compiling kernel modules.

Now, a development RFC. The only difference between ppp.o and ppp-4mppe.o
is the maximum allowed size of the argument block sent to the kernel ppp
module by ioctl calls. This is defined by CCP_MAX_OPTION_LENGTH, and is
increased from 32 bytes to 64 bytes to allow MPPE keys to be communicated
from the ppp daemon to the mppe kernel module.

If the communication protocol was changed so that a pointer to the key was
sent, rather than the key itself, then people wouldn't need to replace
their vendor's ppp.o module, they'd just add the ppp-mppe.o module, and
replace pppd. The ppp-mppe.o module would need to take the pointer and
copy the key from user to kernel space.

Any objections? Anyone care to help me develop and test the changes?

-- 

  Charlie Brady                         charlieb at e-smith.com
  http://www.e-smith.org (development)  http://www.e-smith.com (corporate)
  Phone: +1 (613) 368 4376 or 564 8000  Fax: +1 (613) 564 7739
  e-smith, inc. 1500-150 Metcalfe St, Ottawa, ON K2P 1P1 Canada