README.pppol2tp

PPPoL2TP plugin
===============

The pppol2tp plugin lets pppd use the Linux kernel driver pppol2tp.ko
to pass PPP frames in L2TP tunnels. The driver was integrated into the
kernel in the 2.6.23 release. For kernels before 2.6.23, an
out-of-tree kernel module is available from the pppol2tp-kmod package
in the OpenL2TP project.

Note that pppd receives only PPP control frames over the PPPoL2TP
socket; data frames are handled entirely by the kernel.

The pppol2tp plugin adds extra arguments to pppd and uses the Linux kernel
PPP-over-L2TP driver to set up each session's data path.

Arguments are:-

pppol2tp <fd>                   - FD for PPPoL2TP socket
pppol2tp_lns_mode               - PPPoL2TP LNS behavior. Default off.
pppol2tp_send_seq               - PPPoL2TP enable sequence numbers in
                                  transmitted data packets. Default off.
pppol2tp_recv_seq               - PPPoL2TP enforce sequence numbers in
                                  received data packets. Default off.
pppol2tp_reorderto <millisecs>  - PPPoL2TP data packet reorder timeout.
                                  Default 0 (no reordering).
pppol2tp_debug_mask <mask>      - PPPoL2TP debug mask. Bitwise OR of
				  1 - verbose debug
				  2 - control
				  4 - kernel transport
				  8 - ppp packet data
				  Default: 0 (no debug).
pppol2tp_ifname <ifname>	- Name of PPP network interface visible
				  to "ifconfig" and "ip link".
				  Default: "pppN"
pppol2tp_tunnel_id <id>		- L2TP tunnel_id tunneling this PPP
				  session.
pppol2tp_session_id <id>	- L2TP session_id of this PPP session.
				  The tunnel_id/session_id pair is used
				  when sending event messages to openl2tpd.

pppd will typically be started by an L2TP daemon for each L2TP sesion,
supplying one or more of the above arguments as required. The pppd
user will usually have no visibility of these arguments.

Two hooks are exported by this plugin.

void (*pppol2tp_send_accm_hook)(int tunnel_id, int session_id,
     uint32_t send_accm, uint32_t recv_accm);
void (*pppol2tp_ip_updown_hook)(int tunnel_id, int session_id, int up);

Credits
=======

This plugin was developed by Katalix Systems as part of the OpenL2TP
project, http://openl2tp.sourceforge.net. OpenL2TP is a full-featured
L2TP client-server, suitable for use as an enterprise L2TP VPN server
or a VPN client.

Please copy problems to the OpenL2TP mailing list:
openl2tp-users@lists.sourceforge.net.

Maintained by:
	James Chapman
	jchapman@katalix.com
	Katalix Systems Ltd
	http://www.katalix.com