Re: QoS, setting skb->priority

On Wed, 3 May 2006 13:58:06 -0300 (ART)
Rui Cristo <[email protected]> wrote:

> How can I set the field skb->priority? Some function, ioctl?
>   I need this to configure the egress mapping (vconfig) and tell
>   which priority my frames are to egress depending on skb->priority.
>    

I don't think this question is specific to vlans, but I'll try to
answer anyway.

It looks to me like in general the kernel just uses IPV4 TOS flags to
set the skb->priority flag.  The system call you give below should
override this mechanism, and I'm not sure why this doesn't work.

If you're feeling adventurous you could create your own iptables
kernel module (see http://www.linuxjournal.com/node/7184/print) which
could peek at skbuffs at the NF_IP_POST_ROUTING step and set
skb->priority based on absolutely any parameter you choose.

On the other hand it may be that the default TOS based skb->priority
setting is good enough for your purposes....

Alex


>   I'm trying to use this:
>    
>   int val = 2;
>   setsockopt(sockfd, SOL_SOCKET, SO_PRIORITY, (char*) &val,
>   sizeof(val));
>    
>   It doesnt work. I`m afraid that this approach doesnt change the
>   skb->priority field. Can Anyone Help?
> 
> 		
> ---------------------------------