.. _interface:

.. toctree::

Creating an Interface
======================

Skills to be Learned
--------------------

#. Create a veth interface in Linux host
#. Assign an IP address to one end of the veth interface in the Linux host
#. Create a vpp host-interface that connected to one end of a veth interface via AF_PACKET
#. Add an ip address to a vpp interface

VPP commands learned in this exercise
--------------------------------------

#. `create host-interface <https://docs.fd.io/vpp/17.04/clicmd_src_vnet_devices_af_packet.html#clicmd_create_host-interface>`_
#. `set int state <https://docs.fd.io/vpp/17.04/clicmd_src_vnet.html#clicmd_set_interface_state>`_
#. `set int ip address <https://docs.fd.io/vpp/17.04/clicmd_src_vnet_ip.html#clicmd_set_interface_ip_address>`_
#. `show hardware <https://docs.fd.io/vpp/17.04/clicmd_src_vnet.html#clicmd_show_hardware-interfaces>`_
#. `show int <https://docs.fd.io/vpp/17.04/clicmd_src_vnet.html#clicmd_show_interfaces>`_
#. `show int addr <https://docs.fd.io/vpp/17.04/clicmd_src_vnet.html#clicmd_show_interfaces>`_
#. `trace add <https://docs.fd.io/vpp/17.04/clicmd_src_vlib.html#clicmd_trace_add>`_
#. `clear trace <https://docs.fd.io/vpp/17.04/clicmd_src_vlib.html#clicmd_clear_trace>`_
#. `ping <https://docs.fd.io/vpp/17.04/clicmd_src_vnet_ip.html#clicmd_ping>`_
#. `show ip neighbors <https://docs.fd.io/vpp/21.06/db/dba/clicmd_src_vnet_ip-neighbor.html#clicmd_show_ip_neighbors>`_
#. `show ip fib <https://docs.fd.io/vpp/17.04/clicmd_src_vnet_fib.html#clicmd_show_ip_fib>`_

Topology
---------

.. figure:: /_images/Create_Interface_Topology.jpg
  :alt: Figure: Create Interface Topology

  Figure: Create Interface Topology

Initial State
--------------

The initial state here is presumed to be the final state from the previous sections
of the tutorial.
 
Create veth interfaces on host
-------------------------------

In Linux, there is a type of interface call 'veth'. Think of a 'veth'
interface as being an interface that has two ends to it (rather than
one).

Create a veth interface with one end named **vpp1out** and the other
named **vpp1host**

.. code-block:: console

  $ sudo ip link add name vpp1out type veth peer name vpp1host

Turn up both ends:

.. code-block:: console

  $ sudo ip link set dev vpp1out up
  $ sudo ip link set dev vpp1host up

Assign an IP address
---------------------

.. code-block:: console

  $ sudo ip addr add 10.10.1.1/24 dev vpp1host

Display the result:

.. code-block:: console

  $ ip addr show vpp1host
  5: vpp1host@vpp1out: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether e2:0f:1e:59:ec:f7 brd ff:ff:ff:ff:ff:ff
    inet 10.10.1.1/24 scope global vpp1host
       valid_lft forever preferred_lft forever
    inet6 fe80::e00f:1eff:fe59:ecf7/64 scope link
       valid_lft forever preferred_lft forever

Create vpp host-interface
--------------------------

Make sure VPP is running, if not start it.

.. code-block:: console

    $ ps -eaf | grep vpp
    vagrant   2141   903  0 05:28 pts/0    00:00:00 grep --color=auto vpp
    # vpp is not running, so start it
    $ sudo /usr/bin/vpp -c startup1.conf

These commands are run from the vpp shell. Enter the VPP shell with the following
command:

.. code-block:: console

    $ sudo vppctl -s /run/vpp/cli-vpp1.sock
        _______    _        _   _____  ___
     __/ __/ _ \  (_)__    | | / / _ \/ _ \
     _/ _// // / / / _ \   | |/ / ___/ ___/
     /_/ /____(_)_/\___/   |___/_/  /_/
    
    vpp#

Create a host interface attached to **vpp1out**.

.. code-block:: console

  vpp# create host-interface name vpp1out
  host-vpp1out

Confirm the interface:

.. code-block:: console

  vpp# show hardware
                Name                Idx   Link  Hardware
  host-vpp1out                       1     up   host-vpp1out
  Ethernet address 02:fe:d9:75:d5:b4
  Linux PACKET socket interface
  local0                             0    down  local0
  local

Turn up the interface:

.. code-block:: console

  vpp# set int state host-vpp1out up

Confirm the interface is up:

.. code-block:: console

  vpp# show int
                Name               Idx    State  MTU (L3/IP4/IP6/MPLS)     Counter          Count
  host-vpp1out                      1      up          9000/0/0/0
  local0                            0     down          0/0/0/0

Assign ip address 10.10.1.2/24

.. code-block:: console

  vpp# set int ip address host-vpp1out 10.10.1.2/24

Confirm the ip address is assigned:

.. code-block:: console

  vpp# show int addr
  host-vpp1out (up):
    L3 10.10.1.2/24
  local0 (dn):