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

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    |                      |initiator |
   |responder+----------------------+strongSwan|
   +---------+                      +----------+
                        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=@roadwarrior.vpn.example.com
    leftsubnet=192.168.5.0/24

    # remote: (vpp gateway)
    rightid=@vpp.home
    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 vpp.home
   ikev2 profile set pr1 id remote fqdn roadwarrior.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

   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:

::

   $ sudo docker exec sswan ipsec up initiator

   ...
   CHILD_SA initiator{1} established with SPIs c320c95f_i 213932c2_o and TS 192.168.5.0/24 === 192.168.3.0/24
   connection 'initiator' established successfully

::

   vpp# show ikev2 sa details

   iip 192.168.10.1 ispi 7849021d9f655f1b rip 192.168.10.2 rspi 5a9ca7469a035205
    encr:aes-gcm-16 prf:hmac-sha2-256  dh-group:modp-2048
    nonce i:692ce8fd8f1c1934f63bfa2b167c4de2cff25640dffe938cdfe01a5d7f6820e6
          r:3ed84a14ea8526063e5aa762312be225d33e866d7152b9ce23e50f0ededca9e3
    SK_d    9a9b896ed6c35c78134fcd6e966c04868b6ecacf6d5088b4b2aee8b05d30fdda
    SK_e  i:00000000: 1b1619788d8c812ca5916c07e635bda860f15293099f3bf43e8d88e52074b006
            00000020: 72c8e3e3
          r:00000000: 89165ceb2cef6a6b3319f437386292d9ef2e96d8bdb21eeb0cb0d3b92733de03
            00000020: bbc29c50
    SK_p  i:fe35fca30985ee75e7c8bc0d7bc04db7a0e1655e997c0f5974c31458826b6fef
          r:0dd318662a96a25fcdf4998d8c6e4180c67c03586cf91dab26ed43aeda250272
    identifier (i) id-type fqdn data roadwarrior.vpn.example.com
    identifier (r) id-type fqdn data vpp.home
      child sa 0:encr:aes-gcm-16  esn:yes
       spi(i) c320c95f spi(r) 213932c2
       SK_e  i:2a6c9eae9dbed202c0ae6ccc001621aba5bb0b01623d4de4d14fd27bd5185435
             r:15e2913d39f809040ca40a02efd27da298b6de05f67bd8f10210da5e6ae606fb
       traffic selectors (i):0 type 7 protocol_id 0 addr 192.168.5.0 - 192.168.5.255 port 0 - 65535
       traffic selectors (r):0 type 7 protocol_id 0 addr 192.168.3.0 - 192.168.3.255 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=1.02 ms
   64 bytes from 192.168.5.2: icmp_seq=2 ttl=63 time=0.599 ms
