[BEHAVE] Re: TURN Issue: Preserving bits in the IP header

[Stephane Bortzmeyer <[e-mail]>]

On Tue, Jan 08, 2008 at 12:23:16PM +0200,
 Rémi Denis-Courmont <[e-mail]> wrote 
 a message of 33 lines which said:

> As far as I know the Winsock (Windows), Linux and BSD socket API
> implementations, none of them provide per-packet TOS and ECN bit
> specification.

To ease the current survey of implementations, I wrote the attached
small program, that you can run on your system (tested on many Unix,
VMS - if someone wants to run a TURN server on VMS - and Windows XP),
to see what bits in the IP header an ordinary application can *set*
(wether it can *gets* them is another issue).

To compile:

make

To run:

make test

If you are root, I suggest to run it with and without root privileges,
the results may be different (for instance on Linux).

It may be a good idea to send the results only to me or to the persons
responsible for the tests (see
http://www1.ietf.org/mail-archive/web/behave/current/msg03248.html).

A big warning: the program only tests that the system accepts the
option, not that it complies. 

Executive summary of the results so far: TTL, ECN and DSCP seem to be
easily settable. precedence and DF are more questionable.

Some results:

My UID is 1000
The system is Linux 2.6.8-4-k7, the machine is i686
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
[PROBLEM] Cannot set the precedence to 160:  (Operation not permitted)
DF set through PMTU successfully set to 2
DF clear through PMTU successfully set to 0

My UID is 0
The system is Linux 2.6.8-4-k7, the machine is i686
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
DF set through PMTU successfully set to 2
DF clear through PMTU successfully set to 0

My UID is 1055
The system is OSF1 V5.1, the machine is alpha
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

My UID is 54131
The system is FreeBSD 6.2-RELEASE, the machine is i386
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

My UID is 1000
The system is NetBSD 3.1, the machine is sparc64
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

My UID is 0
The system is Darwin 9.1.0, the machine is i386
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

My UID is 1005
The system is CYGWIN_NT-5.1 1.5.24(0.156/4/2), the machine is i686
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

My UID is 8491703
The system is OpenVMS 0, the machine is HP_rx2600__(1.40GHz/1.5MB)
TTL successfully set to 10
TOS successfully set to 8
ECN successfully set to 2
precedence successfully set to 160
No known way to set the DF bit on this system

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