I just hacked a patch for squid 2.5-stable3 for setting classids for connections based on the requesting src/user. The classids are set using the SO_PRIORITY socket option (skb->priority field). Classification based on this field needs support from the qdisc but iirc all classful qdiscs support this.
Example:
Place all requests from 10.0.0.0/8 in class 10:100. No filters need to be set up.
--------- acl special_service_net src 10.0.0.0/255.255.255.0 tcp_outgoing_priority 10:100 special_service_net ---------
The patch is available at http://trash.net/~kaber
Patrick
