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[SCTP-Discussion] Re: sctplib-1.3.1 and add-ip


Chronological Thread 
  • From: Ilknur Aydin <aydin AT mail.eecis.udel.edu>
  • To: Andreas Jungmaier <andreas.jungmaier AT web.de>
  • Cc: MichaelTuexen <tuexen AT fh-muenster.de>, cshen AT mail.eecis.udel.edu, discussion AT sctp.de
  • Subject: [SCTP-Discussion] Re: sctplib-1.3.1 and add-ip
  • Date: Thu Mar 31 19:22:01 2005
  • List-id: SCTP Discussions <discussion.sctp.de>

Hi Andreas,

thanks for your reply, I followed README files, and now I am able to run sample programs as un-previleged user.


best regards,
ilknur

On Wed, 30 Mar 2005, Andreas Jungmaier wrote:

Hi all,

indeed I am back - so I can give you a short reply here
(may be able to provide a longer answer tonite):

Please read README.sctpd first !

Ilknur Aydin
<aydin AT mail.eecis.udel.edu>
schrieb am 29.03.05 00:56:04:

Hi Michael,

I have not used the developer version of Andreas, so I might not be right
here:
- test_tool might not be the program you want to use. Use combined_server
or echo_server as a server and terminal as a client.

yes, as "root" , I first I ran "sctpd" and then echo_server and terminal.
And these programs worked together this way. But if I run them as a user
w/o root previliges they can not start I get the error:

Connect failed: Permission denied
sctp_initLibrary(): Unknown error in Adaptation-module (maybe IPC file
/tmp/s.sct not removed).

I check the source code for echo_server and terminal programs, they both
include sctp_wrapper.h instead of ua.h. As far as I understand this means
the programs do not connect to the sctpd but instead try opening sockets
themselves using SCTP_xxx library calls.

I do not remember why and when that documentation file got into this
release, but ir refers to an entirely old and outdated and deprecated
source file. It does in no way apply to this release of sctpd. Sorry about
that. It will (have to) be removed from further releases.

how do I make user programs run as un-previleged users and connect/use
sctpd library calls?

The error message should be self-explanatory !
The IPC file was not removed. This needs to be done manually (or by a script).
The (privileged) sctpd communicates with the (unprivileged) user programs
via local IPC (unix domain sockets on unix systems, TCP sockets in Windoze)
and creates a socket in the /tmp directory.
Naturally, this must be writeable/readable for the user that executes the
(unprivileged) programs.
The start-sctpd script assumes a group "sctp" (i think) and changes read/write
permissions of the IPC socket to that group. But you can have any group
or user access this socket.

Another question: in case I am OK to run programs as root and use sctplib
functions as in sample programs echo_server, terminal, will there be any
crucial problems in operating programs with sctplib ??

- do not rely (too much) on documentation. Use the source code of the
implementation and of the examples to see how things work. Sometimes
you have the time to update the code but you forgot / have not the time
to update the documentation.

I agree with Michael here. The (nicely formatted PDF) documentation is usually
outdated. The README files howver should be quite up to date.

- regarding the link to get the version: it might be right, it is not
'officially released/tested/supported'. Possibly Andreas has continued
to develop it...

Michael: Maybe you can ping Sebastian Rohde or Thomas to create another
snapshot...I currently have to finish up my Ph.D. so I have no bandwidth
left (and I have to dedicate the rest of the available time to my little
daughter :-)


Since the version run on Linux only and I currently do not have the time
to port it to BSD, you have to ask Andreas for support. Or is anyone else
jumping in?

I need to run linux kernel 2.4.40, not BSD.

Basically it should run on FreeBSD. On Linux it ran okay.

But yes, I will ask Andreas for support questions then. Should I continue
posting such emails to the discussion list as well ??


Definitely !

I need to run sctplib1.3.1 with add-ip support.

I checked
announce AT sctp.de
list archives, saw the announcement message

http://www.sctp.de/pipermail/announce/2004-August/000042.html

and hence downloaded sctplib1.3.1 from the link

http://www.exp-math.uni-essen.de/~ajung/src/sctplib-1.3.1.tar.gz

I un-tar sctplib1.3.1 and followed the instructions in README and
README.sctpd and used commands:

./configure
make
make install

to built sctplib1.3.1 and then I started "sctpd" with root permissions.

I ran one of the sample programs "daytime_server" as server UA and
"test_tool" with a script as the client UA (User Application) on the same
machine. It seems they worked together.

BUT I start checking the documents under sctplib/manual/ directory. In the
manual sctpdlib-doc.pdf titled "SCTP daemons' User Application Guidelines:
using the sctpdlib" it says a UA should include "sctpdlib/ua.h" and
mentions a directory "sctpd_programs" (for sample programs that uses
sctpd). However, I could not find where is ua.h and sctd_programs
directory.

That documentation may be out of date. One of the things we may need
to fix ;-)


Also, I checked the programs under sctplib/programs, they do not include
ua.h and they use SCTP library calls (for instance SCTP_initLibrary())
instead of sctpd function calls (sctpd_initLibrary()).

Yes - and that is the correct way of doing things...


Also, I could not find signs in the source files, sample programs, or
documents that add-ip is suported in this snapshot and if so how I could
use it.

So,

(1) I am wondering if the link above is the correct place to get
sctplib1.3.1 ? May be it is but I did not built it correctly that is why I
do not have ua.h and sctpd_programs ?? (BTW, I built sctplib1.3.1 under
linux kernel 2.4.20.)

That is fine. Have a look at the README files in the main directory.
These are important !!!


(2) Or may be the documentation coming with this release is not consistent
? But then how to make sure that programs really use/communicate sctp
library via sctpd central daemon ?

Look at README.sctpd


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