rburkholder / cppofc

C++ based openflow packet encoder/decoder - no longer active - migrating from openflow to p4/xdp/ebpf

cppofc

C++ based openflow packet encoder/decoder

• a focus on decoding openflow v1.4.1 protocol packets for use with openvswitch
• being a distributed solution running on hypervisors, routers, and switches for managing traffic end to end
• anticpated use case:
  • make use of logcabin/raft to create a distributed controller
  • use distributed network minmax algorithms based upon link bandwidth to manage routes and traffic
  • load a linux distribution onto Mellanox SN2700 switches, and make use of the hardware offload functionality currently in development for the kernel and openvswitch
  • control hypervisors for traffic encapsulation and function chaining

Build boost:

wget https://dl.bintray.com/boostorg/release/1.65.1/source/boost_1_65_1.tar.gz
tar zxvf boost_1_65_1.tar.gz
cd boost_1_65_1
sh booststrap.sh
sudo ./b2 --layout=versioned variant=release link=shared threading=multi runtime-link=shared install

A test setup:

# show existing service
ovs-vsctl show
# add two namespaces
ip netns add left
ip netns add right
# turn up lo in the namespaces
ip netns exec left ip link set dev lo up
ip netns exec right ip link set dev lo up
# add a bridge
ovs-vsctl add-br ovsbr0
# set controller of the bridge for openflow
ovs-vsctl set-fail-mode ovsbr0 secure
ovs-vsctl set-controller ovsbr0 tcp:0.0.0.0:6633
# bridge needs to be turned up as that is how it handles some stp stuff
ip link set dev ovsbr0 up
ip link set dev ovs-system up
# add two ports
ovs-vsctl add-port ovsbr0 ethleft -- set interface ethleft type=internal
ovs-vsctl add-port ovsbr0 ethright -- set interface ethright type=internal
# move the two interfaces into the namespaces
ip link set dev ethleft netns left
ip link set dev ethright netns right
# turn the interfaces up
ip netns exec right ip link set dev ethright up
ip netns exec left ip link set dev ethleft up
# add addresses to the interfaces
ip netns exec left ip addr add dev ethleft 172.16.1.1/24
ip netns exec right ip addr add dev ethright 172.16.1.2/24
# confirm connectivity with a ping
ip netns exec right ping 172.16.1.1

Dump Flows:

ovs-ofctl dump-flows ovsbr0

Dump rules:

ovs-appctl dpif/dump-flows ovsbr0

Show port assignments:

ovs-appctl dpctl/show

destination:

Remove the link layer header
Find the destination IP address in the IP header
Do a table lookup to determine the IP address of the next hop
Determine link layer address of the next hop
Add link layer header to packet
Queue packet for sending
Send or drop packet (if link is congested)

ncira extensions

look in

• https://github.com/osrg/openvswitch/blob/master/include/openflow/nicira-ext.h
• https://ryu.readthedocs.io/en/latest/nicira_ext_ref.html