VPP as IKEv2 initiator and strongSwan as responder
==================================================

Prerequisites
-------------

To make the examples easier to configure ``docker`` it is required to
pull strongSwan docker image. The networking is done using Linux’ veth
interfaces and namespaces.

Setup
-----

First a topology:

::

   192.168.3.2                      192.168.5.2
        +                           loopback
        |                                 +
   +----+----+ 192.168.10.2         +-----+----+
   |  VPP    |                      |strongSwan|
   |initiator+----------------------+responder |
   +---------+                      +----------+
                        192.168.10.1

Create veth interfaces and namespaces and configure them:

::

   sudo ip link add gw type veth peer name swanif
   sudo ip link set dev gw up

   sudo ip netns add ns
   sudo ip link add veth_priv type veth peer name priv
   sudo ip link set dev priv up
   sudo ip link set dev veth_priv up netns ns

   sudo ip netns exec ns \
     bash -c "
       ip link set dev lo up
       ip addr add 192.168.3.2/24 dev veth_priv
       ip route add 192.168.5.0/24 via 192.168.3.1"

Create directory with strongswan configs that will be mounted to the
docker container

::

   mkdir /tmp/sswan

Create the ``ipsec.conf`` file in the ``/tmp/sswan`` directory with
following content:

::

   config setup
     strictcrlpolicy=no

   conn initiator
     mobike=no
     auto=add
     type=tunnel
     keyexchange=ikev2
     ike=aes256gcm16-prfsha256-modp2048!
     esp=aes256gcm16-esn!

   # local:
     leftauth=psk
     leftid=@sswan.vpn.example.com
     leftsubnet=192.168.5.0/24

   # remote: (gateway)
     rightid=@roadwarrior.vpp
     right=192.168.10.2
     rightauth=psk
     rightsubnet=192.168.3.0/24

``/tmp/sswan/ipsec.secrets``

::

   : PSK 'Vpp123'

``/tmp/sswan/strongswan.conf``

::

   charon {
     load_modular = yes
     plugins {
       include strongswan.d/charon/*.conf
     }
     filelog {
       /tmp/charon.log {
         time_format = %b %e %T
         ike_name = yes
         append = no
         default = 2
         flush_line = yes
       }
     }
   }
   include strongswan.d/*.conf

Start docker container with strongSwan:

::

    docker run --name sswan -d --privileged --rm --net=none \
     -v /tmp/sswan:/conf -v /tmp/sswan:/etc/ipsec.d philplckthun/strongswan

Finish configuration of initiator’s private network:

::

   pid=$(docker inspect --format "{{.State.Pid}}" sswan)
   sudo ip link set netns $pid dev swanif

   sudo nsenter -t $pid -n ip addr add 192.168.10.1/24 dev swanif
   sudo nsenter -t $pid -n ip link set dev swanif up

   sudo nsenter -t $pid -n ip addr add 192.168.5.2/32 dev lo
   sudo nsenter -t $pid -n ip link set dev lo up

Start VPP …

::

   sudo /usr/bin/vpp unix { \
         cli-listen /tmp/vpp.sock \
         gid $(id -g) } \
         api-segment { prefix vpp } \
         plugins { plugin dpdk_plugin.so { disable } }

… and configure it:

::

   create host-interface name gw
   set interface ip addr host-gw 192.168.10.2/24
   set interface state host-gw up

   create host-interface name priv
   set interface ip addr host-priv 192.168.3.1/24
   set interface state host-priv up

   ikev2 profile add pr1
   ikev2 profile set pr1 auth shared-key-mic string Vpp123
   ikev2 profile set pr1 id local fqdn roadwarrior.vpp
   ikev2 profile set pr1 id remote fqdn sswan.vpn.example.com

   ikev2 profile set pr1 traffic-selector local ip-range 192.168.3.0 - 192.168.3.255 port-range 0 - 65535 protocol 0
   ikev2 profile set pr1 traffic-selector remote ip-range 192.168.5.0 - 192.168.5.255 port-range 0 - 65535 protocol 0

   ikev2 profile set pr1 responder host-gw 192.168.10.1
   ikev2 profile set pr1 ike-crypto-alg aes-gcm-16 256 ike-dh modp-2048
   ikev2 profile set pr1 esp-crypto-alg aes-gcm-16 256

   create ipip tunnel src 192.168.10.2 dst 192.168.10.1
   ikev2 profile set pr1 tunnel ipip0
   ip route add 192.168.5.0/24 via 192.168.10.1 ipip0
   set interface unnumbered ipip0 use host-gw

Initiate the IKEv2 connection:

::

   vpp# ikev2 initiate sa-init pr1

::

   vpp# show ikev2 sa details
    iip 192.168.10.2 ispi f717b0cbd17e27c3 rip 192.168.10.1 rspi e9b7af7fc9b13361
    encr:aes-gcm-16 prf:hmac-sha2-256  dh-group:modp-2048
    nonce i:eb0354613b268c6372061bbdaab13deca37c8a625b1f65c073d25df2ecfe672e
          r:70e1248ac09943047064f6a2135fa2a424778ba03038ab9c4c2af8aba179ed84
    SK_d    96bd4feb59be2edf1930a12a3a5d22e30195ee9f56ea203c5fb6cba5dd2bb80f
    SK_e  i:00000000: 5b75b9d808c8467fd00a0923c06efee2a4eb1d033c57532e05f9316ed9c56fe9
            00000020: c4db9114
          r:00000000: 95121b63372d20b83558dc3e209b9affef042816cf071c86a53543677b40c15b
            00000020: f169ab67
    SK_p  i:fb40d1114c347ddc3228ba004d4759d58f9c1ae6f1746833f908d39444ef92b1
          r:aa049828240cb242e1d5aa625cd5914dc8f8e980a74de8e06883623d19384902
    identifier (i) id-type fqdn data roadwarrior.vpp
    identifier (r) id-type fqdn data sswan.vpn.example.com
      child sa 0:encr:aes-gcm-16  esn:yes
       spi(i) 9dffd57a spi(r) c4e0ef53
       SK_e  i:290c681694f130b33d511335dd257e78721635b7e8aa87930dd77bb1d6dd3f42
             r:0a09fa18cf1cf65c6324df02b46dcc998b84e5397cf911b63e0c096053946c2e
       traffic selectors (i):0 type 7 protocol_id 0 addr 192.168.3.0 - 192.168.3.255 port 0 - 65535
       traffic selectors (r):0 type 7 protocol_id 0 addr 192.168.5.0 - 192.168.5.255 port 0 - 65535

Now we can generate some traffic between responder’s and initiator’s
private networks and see it works.

::

   $ sudo ip netns exec ns ping 192.168.5.2
   PING 192.168.5.2 (192.168.5.2) 56(84) bytes of data.
   64 bytes from 192.168.5.2: icmp_seq=1 ttl=63 time=0.450 ms
   64 bytes from 192.168.5.2: icmp_seq=2 ttl=63 time=0.630 ms
