Re: [mpls-linux-general] mpls beta 1.127 - Diffserv

[James R. L. <jl...@mi...>]

Hello,

On Mon, Feb 04, 2002 at 06:02:35PM -0500, ncc49a wrote:
> Hi James,
> 
> 	I am trying out the diffserv functionality for the latest mpls patch.
> 
>  	When I input this instruction:
> 
> $MPLSADM -v -A -O gen:37:eth0 -o 
> ds2exp:0xff:0x1a:0x1:push:gen:37:set:eth0:ipv4:192.168.1.161 
> 
>  	I get the errors saying: 
> 1) Mask for ds2exp is too large, must be less then 0x40
> 2) Out Instr: No such device or address.
> 
>  	I must be using the above instruction wrongly. Can u provide me some 
> pointers on this?

:-) Opps.  grab 1.128 from CVS, it fixes a couple of mask/bounds checking bugs.

> 	Next, for the above mask... is it applied to the DS code point or the entire 
> DS field? I am not sure, but I think "tc" from iproute2 applies the mask to 
> the whole field..., such that a mask of 0x3 and a DS field of 0x6b will give 
> a DS Code Point of 0x1a, which is AF. 

Good question.  I think it is applied to just the DSCP.  In the kernel
I grab the DS field, shift 2 to the right then 'and' it with the mask.
(take a look a mpls_output.c search for 'ipv4_get_dsfield' and you can
see what I'm doing.  You could add a printk (use just like printf) and
add some debugging to help see if it is being done right.


> 
> 	Thanks a lot!
> 
> Paul
> 
> 
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-- 
James R. Leu