l2tp: Add L2TPv3 protocol support
The L2TPv3 protocol changes the layout of the L2TP packet
header. Tunnel and session ids change from 16-bit to 32-bit values,
data sequence numbers change from 16-bit to 24-bit values and PPP-specific
fields are moved into protocol-specific subheaders.
Although this patch introduces L2TPv3 protocol support, there are no
userspace interfaces to create L2TPv3 sessions yet.
Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l2tp/Kconfig b/net/l2tp/Kconfig
index ec88c5c..d60758d 100644
--- a/net/l2tp/Kconfig
+++ b/net/l2tp/Kconfig
@@ -19,6 +19,10 @@
connections. L2TP is also used as a VPN protocol, popular
with home workers to connect to their offices.
+ L2TPv3 allows other protocols as well as PPP to be carried
+ over L2TP tunnels. L2TPv3 is defined in RFC 3931
+ <http://www.ietf.org/rfc/rfc3931.txt>.
+
The kernel component handles only L2TP data packets: a
userland daemon handles L2TP the control protocol (tunnel
and session setup). One such daemon is OpenL2TP
@@ -26,3 +30,24 @@
If you don't need L2TP, say N. To compile all L2TP code as
modules, choose M here.
+
+config L2TP_V3
+ bool "L2TPv3 support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL && L2TP
+ help
+ Layer Two Tunneling Protocol Version 3
+
+ From RFC 3931 <http://www.ietf.org/rfc/rfc3931.txt>.
+
+ The Layer Two Tunneling Protocol (L2TP) provides a dynamic
+ mechanism for tunneling Layer 2 (L2) "circuits" across a
+ packet-oriented data network (e.g., over IP). L2TP, as
+ originally defined in RFC 2661, is a standard method for
+ tunneling Point-to-Point Protocol (PPP) [RFC1661] sessions.
+ L2TP has since been adopted for tunneling a number of other
+ L2 protocols, including ATM, Frame Relay, HDLC and even raw
+ ethernet frames.
+
+ If you are connecting to L2TPv3 equipment, or you want to
+ tunnel raw ethernet frames using L2TP, say Y here. If
+ unsure, say N.