#set speed 100Mbps
echo ">>> setting speed 100Mbps"
ethtool -s eth0 duplex full speed 100
sleep 10

echo ">>> reconfiguring eth0"
#set up interface and queue configuration
ip link set dev eth0 down

#set-channels: 3 tx queues tx0 highest tx2 lowest prio 
ethtool -L eth0 tx 3

#have to disable rrobin
ethtool --set-priv-flags eth0 p0-rx-ptype-rrobin off

#bring up eth0 interface
ip link set dev eth0 up
sleep 20

echo ">>> loading switch config"
#Setup EST schedule with 3 Gates (Q0-Q2). For description of Command parameters, see man tc-taprio.
#3 traffic classes
#priority map: p[0,1,4..15] <-> TC0, p2 <-> TC1, p3 <-> TC2
#queues: read "TC0: 1 queue at offset 0, TC1: 1 queue at offset 1, TC2: 1 queue at offset 2" 
#TC0 <-> Q0, TC1 <-> Q1, and TC2 <-> Q2
tc qdisc replace dev eth0 parent root handle 100 taprio \
   num_tc 3 \
   map 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 \
   queues 1@0 1@1 1@2 \
   base-time 0000 \
   sched-entry S 4 2500000 \
   sched-entry S 2 2500000 \
   sched-entry S 1 5000000 \
   flags 2
#Where num_tc is same as number of queues = 3, map, maps 16 priorities to one of 3 TCs, queues specify the
#Queue associated with each TC, TC0 - One queue @0, TC1 - One queue @1 and TC2 - One queue @2
# sched-entry S 4 125000
#  S - SetGateStates operation
#  4 - Bit mask showing bit 2 set (Q2/TC2)
#  125000 - 125000 nsecs (125 usecs ) duration of Gate open
#  The cycle-time is 500 usec
sleep 10

echo ">>> enabling classifier"
#enable classifier. Classifier is used to mark the packet based on packet meta data. For example UDP port
#number
tc qdisc add dev eth0 clsact
sleep 15
echo ">>> supplying filters"
#Using tc filter command edit the SKB priority based on udp port number. i.e Udp port 5003 -> prio 3 (TC2/Q2), port 5002 -> prio 2 (TC1/Q1),  5001 -> prio 1( TC0/Q0)
tc filter add dev eth0 egress protocol ip prio 1 u32 match ip dport 5003 0xffff action skbedit priority 3
sleep 5
tc filter add dev eth0 egress protocol ip prio 1 u32 match ip dport 5002 0xffff action skbedit priority 2
sleep 5
tc filter add dev eth0 egress protocol ip prio 1 u32 match ip dport 5001 0xffff action skbedit priority 1
sleep 5

#Network core and Driver uses the skb priority to deliver frames to specific h/w queues. In the above case,
#priority 3 SKB (packet) goes to Q2 (4th entry in map in the tc qdisc command), priority 2 SKB goes to Q1
#(3rd entry in map) and priority 1 SKB goes to Q0 (2nd entry in map)

echo ">>> done..."