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LISP and LISP-MN Implementation

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README.md

Overview

The Locator/ID Separation Protocol (LISP) is being developed within the IETF as a potential solution to the routing scalability problem documented in RFC 4984. It uses the concept of Endpoint IDentifiers (EIDs) to name hosts in edge networks, and Routing LOCators (RLOCs) for nodes in transit networks. EIDs and RLOCs are syntactically indistinguishable from current IPv4 and IPv6 addresses, enabling backwards compatibility with the existing Internet architecture. A distributed database, the mapping system, is responsible for maintaining the associations between EIDs and RLOCs. LISP Mobile Node (LISP-MN) is a specification to enable fast host mobility using LISP. Among other nice features, LISP provides interruption-free global provider-independent roaming of IP-addresses with different networks.

The LISPmob project aims to deliver a full implementation of both LISP and LISP-MN for Linux-like systems, but parts of the implementation may be reusable on other Unix-like operating systems.

In version 0.3 the code was generalized and now it not only serves to MNs (Linux or Android), but also can be used in a domestic router (Linux or OpenWRT) to provide LISP routing capabilities (xTR). Please refer to "Router mode" section for details on xTR funcionality, and to section "OpenWRT" or "Android" for specific details on OpenWRT or Android configuration.

LISPmob consists of three major components:

  • data plane
  • control plane
  • tools

Since version 0.3, the user space daemon 'lispd' is responsible for both control plane and data plane functionality. It is responsible for creating a virtual interface for the EID(s), encapsulating/decapsulating packets, maintaining the mapping cache, etc. (data plane functionality) and for sending and receiving control messages, managing interfaces, etc. (control plane functionality), among other functionalities.

The distribution offers some external tools as well, which can be used for various testing and debugging purposes.

The current reference platform for LISPmob development is Ubuntu Server 12.04.1 LTS (Precise Pangolin), OpenWRT 12.09 (Attitude Adjustment) and Android 4.2 (Jelly Bean).

Network Prerequisites

Running LISPmob host on the public Internet requires the following:

  • an EID from a Mapping Service Provider (MSP),
  • the RLOC of the Map-Server that will accept the registration of this EID,
  • an authentication token to register the EID with the Map-Server,
  • the RLOC of a Map-Resolver,
  • the RLOC of a Proxy-ETR,
  • a publicly routable RLOC for the host, which is neither firewalled, nor behind NAT (see however "NAT traversal" section for details on this).

Other than the last item, the above information is used for configuring 'lispd' via the configuration file 'lispd.conf'. See section "OpenWRT" for OpenWRT configuration details and "Android" for Android configuration details.

When used in a MN, the EID will be used by the applications on the host for establishing communications. The RLOC will differ, depending on the network point of attachment, i.e., it will be the IP address assigned to the host in the visited network. See the "References" section for pointers to detailed documentation on the above concepts and network elements.

Visit http://www.lisp4.net/ for more info on the deployment status of the LISP beta-network and how you can join the testbed.

Software Prerequisites

To build LISPmob for a standard Linux, you will need:

  • a Linux hosts with a fairly recent kernel (tested with 3.2.0)
  • a C compiler (tested with gcc)
  • GNU make
  • git, unless you use a tarball
  • OpenSSL development headers
  • libConfuse
  • gengetopt
  • libcap v2+

On Debian-derived Linux distributions (including Ubuntu), installing the following packages will provide all necessary dependencies:

  • 'build-essential'
  • 'git-core'
  • 'libssl-dev'
  • 'libconfuse-dev'
  • 'gengetopt'
  • 'libcap2-bin'

The latest version of the LISPmob source code can be obtained from Github:

git clone git://github.com/LISPmob/lispmob.git

Installation

To build the code for Linux operating as a Mobile Node, run the following in the top-level directory:

make 

To install it in /usr/local/sbin, run

sudo make install

To build the code for OpenWRT you will need the OpenWRT official SDK. However, for your convenience, we encourage you to install the precompiled .ipk, from our website. Check section "OpenWRT" for details.

To build the code for Android, read the specific file dedicated to this platform: README.android.md

Running LISPmob

Once the code is successfully installed on the host, lispd.conf.example should be copied to /etc/lispd.conf and edited with the values obtained from the MSP (see "Network Prerequisites"). Again, see section 'OpenWRT' for OpenWRT details about this. Additionally the host interface used for physical network connectivity (such as 'eth0', 'wlan0' or 'ppp0') must also be specified in the configuration file.

Prior to execute LISPmob, make sure that each external interface (such as 'wan0') has defined a default route with different metric in the routing table (there is a 'default' entry for each outgoing interface). In most cases, this is auto-configured by the operating system during start-up.

Check that sysctl options configuration is correct. Make sure that rp_filter kernel network parameter is disabled. It is disabled by default in OpenWRT, but, for instance, it is enabled by default in Ubuntu. Make sure too that IP forwarding is enabled. It should be enabled by default in OpenWRT.

You can instruct your system to auto-configure these values during system boot-up if you add the following lines to /etc/sysctl.conf. Remember to reboot your system after adding these lines.

net.ipv4.conf.default.rp_filter=0
net.ipv4.conf.all.rp_filter=0
net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1   

The user space daemon can be started by not privileged users. Such user can run the daemon with:

lispd -f /etc/lispd.conf

It will set up networking and register to the mapping system, after which you can enjoy all the benefits of LISP. When 'lispd' is running in MN mode, the EID obtained from the MSP is associated to the 'lispTun0' virtual interface. Two /1 routes covering the full IP addresses space should appear in the routing table. These routes should be pointing to 'lispTun0' device. The following lines shows an example of how 'ip addr' and 'ip route' will look like with IPv4, expect a similar output with IPv6:

$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
    inet <RLOC> brd <RLOC_BROADCAST> scope global eth0
       valid_lft forever preferred_lft forever
3: lispTun0: <POINTOPOINT,UP,LOWER_UP> mtu 1450 qdisc pfifo_fast state UNKNOWN qlen 500
    link/none 
    inet <EID> scope host lispTun0


$ ip route
<RLOC_Network> dev eth0  proto kernel  scope link  src <RLOC>
169.254.0.0/16 dev eth0  scope link  metric 1000
0.0.0.0/1 dev lispTun0
128.0.0.0/1 dev lispTun0
default via <RLOC_GW> dev eth0  metric 100

Version 0.3

Version 0.3 introduced major changes into LISPmob. The most important was to discontinue the separation of data-plane in kernel-space and control-plane in user-space. This resulted in a merged data+control user-space daemon. This is possible thanks to the use of TUN/TAP, creating a TUN virtual interface to deal with data-plane.

This big architectural change was also used to perform a general clean-up and restructuring for most of the code. Due to this, existing (or partially developed) functionalities should be adapted to the new architecture and structure.

This is the list of supported features at this moment:

- Register to the Mapping System
- Request mappings
- DDT Client
- Reply to mapping requests
- Encapsulate data packets
- Decapsulate data packets
- RLOC Probing (user configurable)
- IPv6 full support (EIDs and RLOCs)
- Interface management 
- Multihoming
- Experimental NAT traversal

Router mode

Since version 0.3, LISPmob can be also used to operate as a router. This mode is available to both standard Linux boxes configured as a router as well as OpenWRT capable home routers. When running in router mode, LISPmob serves as a xTR (Ingress/Egress Tunnel Router) that performs LISP encapsulation/decapsulation of packets generated by hosts behind the router.

To enable router operation in a common Linux host, set the the router-mode attribute of the configuration file to 'on'. To configure LISPmob to use it on router mode use the general LISPmob configuration instructions considering the following exception.

An EID /30 (at least) prefix is required instead of a /32 one. For IPv6 you should have a /126 (at least) instead of a /128 one. This prefix should be used as the network prefix for the subnet where the hosts behind the router are allocated. Assign it to an interface and configure it as you would do for a normal network prefix (static configuration, DHCP, etc...). No EID is used for the 'lispTun0' interface in router mode (a local address is automatically used by LISPmob instead).

OpenWRT

Thanks to the versatility of the TUN approach, the code changes to support OpenWRT are minimal. To enable OpenWRT configuration mode and the routing specific operations, the code should have been compiled with the platform=openwrt option during OpenWRT package creation. Please note that the best way to get LISPmob on OpenWRT is get a precompiled binary (either the full system or just the LISPmob package) from the LISPmob website (http://lispmob.org/downloads/openwrt).

LISPmob is also available on official OpenWRT repositories, but it is not guaranteed that this version would be the latest one. You can try to install LISPmob from OpenWRT package feeds with:

opkg update
opkg install lispd

In OpenWRT, the configuration is performed through the OpenWRT standard configuration tool UCI, instead of using 'lispd.conf' file. Configure the UCI file manually in '/etc/config/lispd' (by default), use the UCI CLI application, or use the web interface (if available). The configuration fields are analogue to those in the 'lispd.conf' file.

Android

Since version 0.4, LISPmob can be run on mobile node mode on Android devices. Functionality is limited to one IPv4 EID and one IPv6 EID mapped to the RLOCs of one interface (no multihoming support). If you require NAT traversal, it is recommended for you to first read the NAT traversal section.

To install LISPmob on your device, you need root access and Android version 2.3.6 or higher. LISPmob can be directly installed from Google Play. You can also download the APK file from the LISPmob website or compile the code yourself following the instructions on the README.android.md file.

The Android graphical application allows you to start and stop the lispd daemon and to edit the most important parameters on the configuration file. To configure to the full list of options you have to manually edit the configuration file located in /sdcard/lispd.conf. Please note that if you use the graphical interface, configuration parameters not present there will be reset to their default values.

Due to the large amount of data generated by the lispd daemon, it is recommended to set "log level" to 0 when not debugging.

NAT traversal

Since version 0.3.3, LISPmob includes experimental NAT traversal capabilities (see LISP NAT traversal draft). In order to use NAT traversal with LISPmob you will need a MS and a RTR (Re-encapsulating Tunnel Router) that are NAT traversal capable. If you are using the beta-network, please take into account that, at the time of this writing (release 0.3.3), not all devices on the beta-network have been updated to support NAT traversal yet.

On its current form, NAT traversal support on LISPmob allows to use just one RLOC interface and one EID prefix. If you want to use more than one RLOC interface or to configure several EID prefixes you will need to deactivate the NAT traversal feature (via the config file). If NAT traversal feature is enabled, all IPv6 addresses configured in the RLOC interface will be ignored.

Contact

Should you have questions regarding the use of the LISPmob distribution, please subscribe to the users@lispmob.org mailing list and ask there (https://lispmob.org/mailman/listinfo/users).

If you wish to participate in the development of LISPmob, use the dedicated mailing list, devel@lispmob.org (https://lispmob.org/mailman/listinfo/devel).

Additionally, important announcements are sent to the low volume mailing list announce@lispmob.org (https://lispmob.org/mailman/listinfo/announce).

More interactive help can sometimes be obtained on the '#lispmob' IRC channel on FreeNode.

Bugs you encounter should be filed at the repository's issue tracker on Github.

References

  1. The Locator Identifier Separation Protocol (LISP)
  2. Locator/ID Separation Protocol
  3. LISP Mobile Node
  4. Interworking between Locator/ID Separation Protocol (LISP) and Non-LISP Sites
  5. LISPmob Project
  6. [LISP NAT traversal draft] https://tools.ietf.org/html/draft-ermagan-lisp-nat-traversal-03
  7. [LISP beta-network] http://www.lisp4.net/beta-network/
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