# Introduction

This plugin is a *temporary!* copy of VPP's src/plugins/linux-cp/ plugin,
originally by the following authors:
*   Signed-off-by: Neale Ranns <nranns@cisco.com>
*   Signed-off-by: Matthew Smith <mgsmith@netgate.com>
*   Signed-off-by: Jon Loeliger <jdl@netgate.com>
*   Signed-off-by: Pim van Pelt <pim@ipng.nl>
*   Signed-off-by: Neale Ranns <neale@graphiant.com>

See previous work:
*   [interface mirroring](https://gerrit.fd.io/r/c/vpp/+/30759)
*   [netlink listener](https://gerrit.fd.io/r/c/vpp/+/31122)

My work is intended to be re-submitted for review as a cleanup/rewrite of the
existing Linux CP interface mirror and netlink syncer. 

Follow along on [my blog](https://ipng.ch/s/articles/) for my findings while
I work towards a completed plugin that can copy VPP configuration into Linux
interfaces, and copy Linux configuration changes into VPP (ie. a fully
bidirectional pipe between Linux and VPP).

When the code is complete, this plugin should be able to work seemlessly with
a higher level controlplane like [FRR](https://frrouting.org/) or
[Bird](https://bird.network.cz/), for example as a BGP/OSPF speaking ISP router.

## WARNING!!

The only reason that this code is here, is so that I can make some progress
iterating on the Linux CP plugin, and share my findings with some interested
folks. The goal is NOT to use this plugin anywhere other than a bench. I
intend to contribute the plugin back upstream as soon as it's peer reviewed!

***Pull Requests and Issues will be immediately closed without warning***

VPP's code lives at [fd.io](https://gerrit.fd.io/r/c/vpp), and this copy is
shared only for convenience purposes.

## Building

First, ensure that you can build and run 'vanilla' VPP by using the
[instructions](https://wiki.fd.io/view/VPP/Pulling,_Building,_Running,_Hacking_and_Pushing_VPP_Code).
Then check out this plugin out-of-tree and symlink it in.

```
mkdir ~/src
cd ~/src
git clone https://github.com/pimvanpelt/lcpng.git
ln -s ~/src/vpp/src/plugins/lcpng ~src/lcpng
```

## Running

Ensure this plugin is enabled and the original `linux-cp` plugin is disabled,
that logging goes to stderr (in the debug variant of VPP), and that the features
are dis/enabled, by providing the following `startup.conf`:
```
plugins {
  path ~/src/vpp/build-root/install-vpp_debug-native/vpp/lib/vpp_plugins
  plugin lcpng_if_plugin.so { enable }
  plugin linux_cp_plugin.so { disable }
}

logging {
   default-log-level info
   default-syslog-log-level crit
   ## Set per-class configuration
   class linux-cp/if { rate-limit 10000 level debug syslog-level debug }
}

lcpng {
  default netns dataplane
  lcp-sync
  lcp-auto-subint
}
```

Then, simply `make build` and `make run` VPP which will load the plugin.
```
im@hippo:~/src/vpp$ make run
snort                [debug ]: initialized
snort                [debug ]: snort listener /run/vpp/snort.sock
linux-cp/if          [debug ]: interface_add: [1] sw TenGigabitEthernet3/0/0 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TenGigabitEthernet3/0/0 0
linux-cp/if          [debug ]: interface_add: [2] sw TenGigabitEthernet3/0/1 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TenGigabitEthernet3/0/1 0
linux-cp/if          [debug ]: interface_add: [3] sw TenGigabitEthernet3/0/2 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TenGigabitEthernet3/0/2 0
linux-cp/if          [debug ]: interface_add: [4] sw TenGigabitEthernet3/0/3 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TenGigabitEthernet3/0/3 0
linux-cp/if          [debug ]: interface_add: [5] sw TwentyFiveGigabitEthernete/0/0 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TwentyFiveGigabitEthernete/0/0 0
linux-cp/if          [debug ]: interface_add: [6] sw TwentyFiveGigabitEthernete/0/1 is_sub 0 lcp-auto-subint 1
linux-cp/if          [debug ]: mtu_change: sw TwentyFiveGigabitEthernete/0/1 0
    _______    _        _   _____  ___ 
 __/ __/ _ \  (_)__    | | / / _ \/ _ \
 _/ _// // / / / _ \   | |/ / ___/ ___/
 /_/ /____(_)_/\___/   |___/_/  /_/    

DBGvpp# 
```