l2tpd version 0.69

Now maintained at: http://www.l2tpd.org by: Jeff McAdams [email protected]

Maintained for a time at: http://sourceforge.net/projects/l2tpd by: Scott Balmos [email protected] Jeff McAdams [email protected] David Stipp [email protected]

Based off of l2tpd version 0.60 Copyright (C)1998 Adtran, Inc. Mark Spencer [email protected]

Introduction:

l2tpd is an implementation of the layer two tunneling protocol. It works in userspace completely (although kernel work is planned after the userspace version is stablized). l2tpd works by opening a pseudo-tty for communicating with pppd. Although l2tpd was written for Linux, the current version should be highly portable to other UNIX's supported by pppd.

Legal Information:

l2tpd is free software, distributed under the GNU General Public License (GPL) and you should read the LICENSE File if you are not already familiar with the GPL before using the product.

Bugs, Patches, and Code Contribution:

Please send bug reports and patches to either the l2tp mailng list ([email protected]).

In order to contribute code, either with patches, or by direct access to the CVS tree for l2tpd, send e-mail to ([email protected]).

The word "FIXME" is a place holder for code that needs to be in place, or checks that need to be done, but haven't been coded yet. Feel free to fix the fixme's and submit patches!

Release Notes

Version 0.69 should be considered ALPHA. It does NOT completely implement the l2tp specification (RFC 2661), but its pretty close!

The primary use of this ALPHA level code is to test the ability of l2tpd to talk with other LAC and LNS implementations. I hope that everyone who tests the software will send me results on how it worked or failed to work for them.

(theoretically) implemented features

• Proper payload and control packet handling
• Reliable control packet delivery
• Ability to recover from payload errors
• Ability to handle packets with/without length set
• Ability to handle flow control or no flow control
• Most critical AVP's for normal operation
• Challenge authentication
• Hidden AVP's
• Hello's to detect outages
• Handles sync and async packets
• Can act as LNS
• Can be a source of a virtual LAC call
• Reads configuration file
• Automated LAC dialup via config file, including redial
• Can be configured while running via a file system pipe
• Access Control
• Statistics report when sent a SIGUSR1
• ACCM

Major unimplemented specification features

• Rate Adaptive Timeouts
• Out of order packet handling
• Initial/Final LCP states
• Q.931 Result Codes
• Tie Breakers
• Minimum/Maximum BPS
• Call Errors

Important non-specification related features to be added

• More configuration options if needed
• Kernel support for much improved performance

Usage notes on /var/run/l2tp-control

There are a few command line options to l2tpd: -D prevents l2tpd from detaching from terminal and running as a daemon -c use alternate config file -s use alternate secrets file -p use alternate pid file

Upon running l2tpd, a pipe is created in /var/run/l2tp-control. Simple commands can then be echoed to this pipe to control l2tp on the fly. The commands are:

t - create a tunnel to c or - originate an l2tp call on the tunnel identified locally by , or dial the entry h - hang up a call with the local identifier d or - disconnect the tunnel locally identified by or a lac entry s - print out a status summary of currently connected tunnels and sessions

For example, to establish a tunnel to marko.net, one might do:

echo "t marko.net" >/var/run/l2tp-control

l2tpd must be running for this to work.

Various other notes

The PPP options used to be hard coded in l2tp.h. Now they (or at least some) are configurable - see the example config file and read file.[ch].

Sending a SIGUSR1 to l2tpd will cause it to dump its status.

Mailing List

If you would like to contribute to discussions of the architecture of l2tpd, file formats, etc, we encourage you to join the l2tpd mailing list by visiting http://www.l2tpd.org/ and subscribing to our mailing lists.

Original Project Legal Information:

l2tpd is free software, distributed under the GNU General Public License (GPL)and you should read the LICENSE File if you are not already familiar with the GPL before using the product.

If you distribute l2tpd, a modified version, or a derivative product, you MUST not remove Adtran's name from the product nor modify the terms of the copyright.