Jim diGriz QoS Script

N.B. this is just me dabbling in QoS again, and everything here is completely un-usable

Downloadable at https://github.com/jimdigriz/jdg-qos

Available bandwidth is variable on todays xDSL connections due to contention, so my new generation of QoS script tries to be work conserving throughout and relying on queue lengths to decide what to dequeue/drop.

The TBF at the head is to just slightly clip short of any buffers between (and inside) the modem to the DSLAM at the local exchange.

                                                                   ppp0 [root] (egress)  -> ...
ingress [ffff:] -> basic action mirred egress redirect dev ifb0 -> ifb0 [root] (ingress) -> ...

tbf [1:] -> prio [10:] --{10:1}--> tbf [100:] (EF)
                       --{10:2}--> ddr [200:] (AF) --> 12 red queues
                       --{10:3}--> red [300:] (BE)

N.B. prio is built using 'bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1'

• kernel 2.6.32.x does not seem to do ToS u32 matching as it can in the 3.x kernels so DRR drops all incoming traffic. Its as if mangle has not yet had a chance to mark the packet

• branch 10:2 needs amending so that it is DDR to four PRIO queues (three bands each) from which RED hangs off each.
• support 6to4/6in4 IPv6 tunnels (also for 6to4 ToS/DSCP marking is not copied to outer external IPv4 packet)
• add support for CHOKe