Setup TLS Connection

If you want to use secure channel to connect OpenFlow switches, you need to use TLS connection. This document describes how to setup OS-Ken to connect to the Open vSwitch over TLS.

Configuring a Public Key Infrastructure

If you don't have a PKI, the ovs-pki script included with Open vSwitch can help you. This section is based on the INSTALL.SSL in the Open vSwitch source code.

NOTE: How to install Open vSwitch isn't described in this document. Please refer to the Open vSwitch documents.

Create a PKI by using ovs-pki script:

% ovs-pki init
(Default directory is /usr/local/var/lib/openvswitch/pki)

The pki directory consists of controllerca and switchca subdirectories. Each directory contains CA files.

Create a controller private key and certificate:

% ovs-pki req+sign ctl controller

ctl-privkey.pem and ctl-cert.pem are generated in the current directory.

Create a switch private key and certificate:

% ovs-pki req+sign sc switch

sc-privkey.pem and sc-cert.pem are generated in the current directory.

Testing TLS Connection

Configuring ovs-vswitchd to use CA files using the ovs-vsctl "set-ssl" command, e.g.:

% ovs-vsctl set-ssl /etc/openvswitch/sc-privkey.pem \
  /etc/openvswitch/sc-cert.pem \
  /usr/local/var/lib/openvswitch/pki/controllerca/cacert.pem
% ovs-vsctl add-br br0
% ovs-vsctl set-controller br0 ssl:127.0.0.1:6633

Substitute the correct file names, if they differ from the ones used above. You should use absolute file names.

Run OS-Ken with CA files:

% osken-manager --ctl-privkey ctl-privkey.pem \
              --ctl-cert ctl-cert.pem \
              --ca-certs /usr/local/var/lib/openvswitch/pki/switchca/cacert.pem \
              --verbose

You can see something like:

loading app os_ken.controller.ofp_handler
instantiating app os_ken.controller.ofp_handler
BRICK ofp_event
  CONSUMES EventOFPSwitchFeatures
  CONSUMES EventOFPErrorMsg
  CONSUMES EventOFPHello
  CONSUMES EventOFPEchoRequest
connected socket:<SSLSocket fileno=4 sock=127.0.0.1:6633 peer=127.0.0.1:61302> a
ddress:('127.0.0.1', 61302)
hello ev <os_ken.controller.ofp_event.EventOFPHello object at 0x1047806d0>
move onto config mode
switch features ev version: 0x1 msg_type 0x6 xid 0xb0bb34e5 port OFPPhyPort(port
_no=65534, hw_addr='\x16\xdc\xa2\xe2}K', name='br0\x00\x00\x00\x00\x00\x00\x00\x
00\x00\x00\x00\x00\x00', config=0, state=0, curr=0, advertised=0, supported=0, p
eer=0)
move onto main mode