# CORE Services

* Table of Contents
{:toc}

## Services

CORE uses the concept of services to specify what processes or scripts run on a
node when it is started. Layer-3 nodes such as routers and PCs are defined by
the services that they run.

Services may be customized for each node, or new custom services can be
created. New node types can be created each having a different name, icon, and
set of default services. Each service defines the per-node directories,
configuration files, startup index, starting commands, validation commands,
shutdown commands, and meta-data associated with a node.

**NOTE:**
   Network namespace nodes do not undergo the normal Linux boot process
   using the **init**, **upstart**, or **systemd** frameworks. These
   lightweight nodes use configured CORE *services*.

## Default Services and Node Types

Here are the default node types and their services:

| Node type | Services |
|---|---|
| *router* | zebra, OSFPv2, OSPFv3, and IPForward services for IGP link-state routing. |
| *host* | DefaultRoute and SSH services, representing an SSH server having a default route when connected directly to a router. |
| *PC* | DefaultRoute service for having a default route when connected directly to a router. |
| *mdr* | zebra, OSPFv3MDR, and IPForward services for wireless-optimized MANET Designated Router routing. |
| *prouter* | a physical router, having the same default services as the *router* node type; for incorporating Linux testbed machines into an emulation. |

Configuration files can be automatically generated by each service. For
example, CORE automatically generates routing protocol configuration for the
router nodes in order to simplify the creation of virtual networks.

To change the services associated with a node, double-click on the node to
invoke its configuration dialog and click on the *Services...* button,
or right-click a node a choose *Services...* from the menu.
Services are enabled or disabled by clicking on their names. The button next to
each service name allows you to customize all aspects of this service for this
node. For example, special route redistribution commands could be inserted in
to the Quagga routing configuration associated with the zebra service.

To change the default services associated with a node type, use the Node Types
dialog available from the *Edit* button at the end of the Layer-3 nodes
toolbar, or choose *Node types...* from the  *Session* menu. Note that
any new services selected are not applied to existing nodes if the nodes have
been customized.

The node types are saved in a **~/.core/nodes.conf** file, not with the
**.imn** file. Keep this in mind when changing the default services for
existing node types; it may be better to simply create a new node type. It is
recommended that you do not change the default built-in node types. The
**nodes.conf** file can be copied between CORE machines to save your custom
types.

## Customizing a Service

A service can be fully customized for a particular node. From the node's
configuration dialog, click on the button next to the service name to invoke
the service customization dialog for that service.
The dialog has three tabs for configuring the different aspects of the service:
files, directories, and startup/shutdown.

**NOTE:**
   A **yellow** customize icon next to a service indicates that service
   requires customization (e.g. the *Firewall* service).
   A **green** customize icon indicates that a custom configuration exists.
   Click the *Defaults* button when customizing a service to remove any
   customizations.

The Files tab is used to display or edit the configuration files or scripts that
are used for this service. Files can be selected from a drop-down list, and
their contents are displayed in a text entry below. The file contents are
generated by the CORE daemon based on the network topology that exists at
the time the customization dialog is invoked.

The Directories tab shows the per-node directories for this service. For the
default types, CORE nodes share the same filesystem tree, except for these
per-node directories that are defined by the services. For example, the
**/var/run/quagga** directory needs to be unique for each node running
the Zebra service, because Quagga running on each node needs to write separate
PID files to that directory.

**NOTE:**
   The **/var/log** and **/var/run** directories are
   mounted uniquely per-node by default.
   Per-node mount targets can be found in **/tmp/pycore.nnnnn/nN.conf/**
   (where *nnnnn* is the session number and *N* is the node number.)

The Startup/shutdown tab lists commands that are used to start and stop this
service. The startup index allows configuring when this service starts relative
to the other services enabled for this node; a service with a lower startup
index value is started before those with higher values. Because shell scripts
generated by the Files tab will not have execute permissions set, the startup
commands should include the shell name, with
something like ```sh script.sh```.

Shutdown commands optionally terminate the process(es) associated with this
service. Generally they send a kill signal to the running process using the
*kill* or *killall* commands. If the service does not terminate
the running processes using a shutdown command, the processes will be killed
when the *vnoded* daemon is terminated (with *kill -9*) and
the namespace destroyed. It is a good practice to
specify shutdown commands, which will allow for proper process termination, and
for run-time control of stopping and restarting services.

Validate commands are executed following the startup commands. A validate
command can execute a process or script that should return zero if the service
has started successfully, and have a non-zero return value for services that
have had a problem starting. For example, the *pidof* command will check
if a process is running and return zero when found. When a validate command
produces a non-zero return value, an exception is generated, which will cause
an error to be displayed in the Check Emulation Light.

**TIP:**
   To start, stop, and restart services during run-time, right-click a
   node and use the *Services...* menu.

## New Services

Services can save time required to configure nodes, especially if a number
of nodes require similar configuration procedures. New services can be
introduced to automate tasks.

### Leveraging UserDefined

The easiest way to capture the configuration of a new process into a service
is by using the **UserDefined** service. This is a blank service where any
aspect may be customized. The UserDefined service is convenient for testing
ideas for a service before adding a new service type.

### Creating New Service

1. Modify the [Example Service File](../daemon/examples/myservices/sample.py)
   to do what you want. It could generate config/script files, mount per-node
   directories, start processes/scripts, etc. sample.py is a Python file that
   defines one or more classes to be imported. You can create multiple Python
   files that will be imported. Add any new filenames to the __init__.py file.

2. Put these files in a directory such as /home/username/.core/myservices
   Note that the last component of this directory name **myservices** should not
   be named something like **services** which conflicts with an existing Python
   name (the syntax 'from myservices import *' is used).

3. Add a **custom_services_dir = /home/username/.core/myservices** entry to the
   /etc/core/core.conf file.
   
   **NOTE:**
   The directory name used in **custom_services_dir** should be unique and
   should not correspond to
   any existing Python module name. For example, don't use the name **subprocess**
   or **services**.

4. Restart the CORE daemon (core-daemon). Any import errors (Python syntax)
   should be displayed in the /var/log/core-daemon.log log file (or on screen).

5. Start using your custom service on your nodes. You can create a new node
   type that uses your service, or change the default services for an existing
   node type, or change individual nodes.

If you have created a new service type that may be useful to others, please
consider contributing it to the CORE project.

## Available Services

### BIRD Internet Routing Daemon
The [BIRD Internet Routing Daemon](https://bird.network.cz/) is a routing daemon; i.e., a software responsible for managing kernel packet forwarding tables. It aims to develop a dynamic IP routing daemon with full support of all modern routing protocols, easy to use configuration interface and powerful route filtering language, primarily targeted on (but not limited to) Linux and other UNIX-like systems and distributed under the GNU General Public License. BIRD has a free implementation of several well known and common routing and router-supplemental protocols, namely RIP, RIPng, OSPFv2, OSPFv3, BGP, BFD, and NDP/RA. BIRD supports IPv4 and IPv6 address families, Linux kernel and several BSD variants (tested on FreeBSD, NetBSD and OpenBSD). BIRD consists of bird daemon and birdc interactive CLI client used for supervision.

In order to be able to use the BIRD Internet Routing Protocol, you must first install the project on your machine.


#### BIRD Package Install
```shell
sudo apt-get install bird
```

#### BIRD Source Code Install
You can download BIRD source code from it's [official repository.](https://gitlab.labs.nic.cz/labs/bird/)
```shell
./configure
make
su
make install
vi /etc/bird/bird.conf
```
The installation will place the bird directory inside */etc* where you will also find its config file.

In order to be able to do use the Bird Internet Routing Protocol, you must modify *bird.conf* due to the fact that the given configuration file is not configured beyond allowing the bird daemon to start, which means that nothing else will happen if you run it. Keeran Marquis has a very detailed example on [Configuring BGP using Bird on Ubuntu](https://blog.marquis.co/configuring-bgp-using-bird-on-ubuntu-14-04lts/) which can be used as a building block to implement your custom routing daemon.


### FRRouting
FRRouting is a routing software package that provides TCP/IP based routing services with routing protocols support such as BGP, RIP, OSPF, IS-IS and more. FRR also supports special BGP Route Reflector and Route Server behavior. In addition to traditional IPv4 routing protocols, FRR also supports IPv6 routing protocols. With an SNMP daemon that supports the AgentX protocol, FRR provides routing protocol MIB read-only access (SNMP Support).

FRR currently supports the following protocols:
* BGP
* OSPFv2
* OSPFv3
* RIPv1
* RIPv2
* RIPng
* IS-IS
* PIM-SM/MSDP
* LDP
* BFD
* Babel
* PBR
* OpenFabric
* EIGRP (alpha)
* NHRP (alpha)

#### FRRouting Package Install
```shell
sudo apt install curl
curl -s https://deb.frrouting.org/frr/keys.asc | sudo apt-key add -
FRRVER="frr-stable"
echo deb https://deb.frrouting.org/frr $(lsb_release -s -c) $FRRVER | sudo tee -a /etc/apt/sources.list.d/frr.list
sudo apt update && sudo apt install frr frr-pythontools
```

#### FRRouting Source Code Install
Building FRR from source is the best way to ensure you have the latest features and bug fixes. Details for each supported platform, including dependency package listings, permissions, and other gotchas, are in the developer’s documentation. 

FRR’s source is available on the project [GitHub page](https://github.com/FRRouting/frr).
```shell
git clone https://github.com/FRRouting/frr.git
```

Change into your FRR source directory and issue:
```shell
./bootstrap.sh
```
Then, choose the configuration options that you wish to use for the installation. You can find these options on FRR's [official webpage](http://docs.frrouting.org/en/latest/installation.html). Once you have chosen your configure options, run the configure script and pass the options you chose:
```shell
./configure \
    --prefix=/usr \
    --enable-exampledir=/usr/share/doc/frr/examples/ \
    --localstatedir=/var/run/frr \
    --sbindir=/usr/lib/frr \
    --sysconfdir=/etc/frr \
    --enable-pimd \
    --enable-watchfrr \
    ...
```
After configuring the software, you are ready to build and install it in your system.
```shell
make && sudo make install
```
If everything finishes successfully, FRR should be installed.


### Docker
Docker service allows running docker containers within CORE nodes.
The running of Docker within a CORE node allows for additional extensibility to
the CORE services. This allows network applications and protocols to be easily
packaged and run on any node.

This service will add a new group to the services list. This will have a service called Docker which will just start the docker service within the node but not run anything. It will also scan all docker images on the host machine. If any are tagged with 'core' then they will be added as a service to the Docker group. The image will then be auto run if that service is selected.

This requires a recent version of Docker. This was tested using a PPA on Ubuntu with version 1.2.0. The version in the standard Ubuntu repo is to old for this purpose (we need --net host).

#### Docker Installation
To use Docker services, you must first install the Docker python image. This is used to interface with Docker from the python service.

```shell
sudo apt-get install docker.io
sudo apt-get install python-pip
pip install docker-py
```
Once everything runs successfully, a Docker group under services will appear. An example use case is to pull an image from [Docker](https://hub.docker.com/). A test image has been uploaded for this purpose:
```shell
sudo docker pull stuartmarsden/multicastping
```
This downloads an image which is based on Ubuntu 14.04 with python and twisted. It runs a simple program that sends a multicast ping and listens and records any it receives. In order for this to appear as a docker service it must be tagged with core.
Find out the id by running 'sudo docker images'. You should see all installed images and the one you want looks like this:
```shell
stuartmarsden/multicastping    latest              4833487e66d2        20 hours
ago        487 MB
```
The id will be different on your machine so use it in the following command:
```shell
sudo docker tag 4833487e66d2 stuartmarsden/multicastping:core
```
This image will be listed in the services after we restart the core-daemon:
```shell
sudo service core-daemon restart
```

### NRL Services
The Protean Protocol Prototyping Library (ProtoLib) is a cross-platform library that allows applications to be built while supporting a variety of platforms including Linux, Windows, WinCE/PocketPC, MacOS, FreeBSD, Solaris, etc as well as the simulation environments of NS2 and Opnet. The goal of the Protolib is to provide a set of simple, cross-platform C++ classes that allow development of network protocols and applications that can run on different platforms and in network simulation environments. While Protolib provides an overall framework for developing working protocol implementations, applications, and simulation modules, the individual classes are designed for use as stand-alone components when possible. Although Protolib is principally for research purposes, the code has been constructed to provide robust, efficient performance and adaptability to real applications. In some cases, the code consists of data structures, etc useful in protocol implementations and, in other cases, provides common, cross-platform interfaces to system services and functions (e.g., sockets, timers, routing tables, etc).

Currently the Naval Research Laboratory uses this library to develop a wide variety of protocols.The NRL Protolib currently supports the following protocols:
* MGEN_Sink
* NHDP
* SMF
* OLSR
* OLSRv2
* OLSRORG
* MgenActor
* arouted

#### NRL Installation
In order to be able to use the different protocols that NRL offers, you must first download the support library itself. You can get the source code from their [official nightly snapshots website](https://downloads.pf.itd.nrl.navy.mil/protolib/nightly_snapshots/).

#### Multi-Generator (MGEN)
Download MGEN from the [NRL MGEN nightly snapshots](https://downloads.pf.itd.nrl.navy.mil/mgen/nightly_snapshots/), unpack it and copy the protolib library into the main folder *mgen*. Execute the following commands to build the protocol.
```shell
cd mgen/makefiles
make -f Makefile.{os} mgen
```

#### Neighborhood Discovery Protocol (NHDP)
Download NHDP from the [NRL NHDP nightly snapshots](https://downloads.pf.itd.nrl.navy.mil/nhdp/nightly_snapshots/).
```shell
sudo apt-get install libpcap-dev libboost-all-dev
wget https://github.com/protocolbuffers/protobuf/releases/download/v3.8.0/protoc-3.8.0-linux-x86_64.zip
unzip protoc-3.8.0-linux-x86_64.zip
``` 
Then place the binaries in your $PATH. To know your paths you can issue the following command
```shell
echo $PATH
```
Go to the downloaded *NHDP* tarball, unpack it and place the protolib library inside the NHDP main folder. Now, compile the NHDP Protocol.
```shell
cd nhdp/unix
make -f Makefile.{os}
```

#### Simplified Multicast Forwarding (SMF)
Download SMF from the [NRL SMF nightly snapshot](https://downloads.pf.itd.nrl.navy.mil/smf/nightly_snapshots/) , unpack it and place the protolib library inside the *smf* main folder.
```shell
cd mgen/makefiles
make -f Makefile.{os}
```

#### Optimized Link State Routing Protocol (OLSR)
To install the OLSR protocol, download their source code from their [nightly snapshots](https://downloads.pf.itd.nrl.navy.mil/olsr/nightly_snapshots/nrlolsr-svnsnap.tgz). Unpack it and place the previously downloaded protolib library inside the *nrlolsr* main directory. Then execute the following commands:
```shell
cd ./unix
make -f Makefile.{os}
```

### Quagga Routing Suite
 Quagga is a routing software suite, providing implementations of OSPFv2, OSPFv3, RIP v1 and v2, RIPng and BGP-4 for Unix platforms, particularly FreeBSD, Linux, Solaris and NetBSD. Quagga is a fork of GNU Zebra which was developed by Kunihiro Ishiguro.
The Quagga architecture consists of a core daemon, zebra, which acts as an abstraction layer to the underlying Unix kernel and presents the Zserv API over a Unix or TCP stream to Quagga clients. It is these Zserv clients which typically implement a routing protocol and communicate routing updates to the zebra daemon.

#### Quagga Package Install
```shell
sudo apt-get install quagga
```

#### Quagga Source Install
First, download the source code from their [official webpage](https://www.quagga.net/).
```shell
sudo apt-get install gawk
```
Extract the tarball, go to the directory of your currently extracted code and issue the following commands.
```shell
./configure
make
sudo make install
```

### Software Defined Networking
Ryu is a component-based software defined networking framework. Ryu provides software components with well defined API that make it easy for developers to create new network management and control applications. Ryu supports various protocols for managing network devices, such as OpenFlow, Netconf, OF-config, etc. About OpenFlow, Ryu supports fully 1.0, 1.2, 1.3, 1.4, 1.5 and Nicira Extensions. All of the code is freely available under the Apache 2.0 license.
```shell
```

#### Installation
##### Prerequisites
```shell
sudo apt-get install gcc python-dev libffi-dev libssl-dev libxml2-dev libxslt1-dev zlib1g-dev
```
##### Ryu Package Install
```shell
pip install ryu
```
##### Ryu Source Install
```shell
git clone git://github.com/osrg/ryu.git
cd ryu; pip install .
```

### Security Services
The security services offer a wide variety of protocols capable of satisfying the most use cases available. Security services such as IP security protocols, for providing security at the IP layer, as well as the suite of protocols designed to provide that security, through authentication and encryption of IP network packets. Virtual Private Networks (VPNs) and Firewalls are also available for use to the user.

#### Installation
```shell
sudo apt-get install ipsec-tools racoon openvpn
```

### UCARP
UCARP allows a couple of hosts to share common virtual IP addresses in order to provide automatic failover. It is a portable userland implementation of the secure and patent-free Common Address Redundancy Protocol (CARP, OpenBSD's alternative to the patents-bloated VRRP).

Strong points of the CARP protocol are: very low overhead, cryptographically signed messages, interoperability between different operating systems and no need for any dedicated extra network link between redundant hosts.

#### Installation
```shell
sudo apt-get install ucarp
```

### Utilities Services
The following services are provided as utilities:
* Default Routing
* Default Muticast Routing
* Static Routing
* SSH
* DHCP
* DHCP Client
* FTP
* HTTP
* PCAP
* RADVD
* ATD

#### Installation
To install the functionality of the previously metioned services you can run the following command:
```shell
sudo apt-get install isc-dhcp-server apache2 libpcap-dev radvd at
```

### XORP routing suite
XORP is an open networking platform that supports OSPF, RIP, BGP, OLSR, VRRP, PIM, IGMP (Multicast) and other routing protocols.  Most protocols support IPv4 and IPv6 where applicable.  It is known to work on various Linux distributions and flavors of BSD.

XORP started life as a project at the ICSI Center for Open Networking (ICON) at the International Computer Science Institute in Berkeley, California, USA, and spent some time with the team at XORP, Inc.  It is now maintained and improved on a volunteer basis by a core of long-term XORP developers and some newer contributors.

XORP's primary goal is to be an open platform for networking protocol implementations and an alternative to proprietary and closed networking products in the marketplace today. It is the only open source platform to offer integrated multicast capability.

XORP design philosophy is:
  * modularity
  * extensibility
  * performance
  * robustness
This is achieved by carefully separating functionalities into independent modules, and by providing an API for each module.

XORP divides into two subsystems. The higher-level ("user-level") subsystem consists of the routing protocols. The lower-level ("kernel") manages the forwarding path, and provides APIs for the higher-level to access.

User-level XORP uses multi-process architecture with one process per routing protocol, and a novel inter-process communication mechanism called XRL (XORP Resource Locator).

The lower-level subsystem can use traditional UNIX kernel forwarding, or Click modular router. The modularity and independency of the lower-level from the user-level subsystem allows for its easily replacement with other solutions including high-end hardware-based forwarding engines.

#### Installation
In order to be able to install the XORP Routing Suite, you must first install scons in order to compile it.
```shell
sudo apt-get install scons
```
Then, download XORP from its official [release web page](http://www.xorp.org/releases/current/).
```shell
http://www.xorp.org/releases/current/
cd xorp
sudo apt-get install libssl-dev ncurses-dev
scons
scons install
```
