iproute2: update ip-l2tp man page
Add documentation about the new l2spec_type parameter for "ip l2tp add
session".
Signed-off-by: James Chapman <jchapman@katalix.com>
diff --git a/man/man8/ip-l2tp.8 b/man/man8/ip-l2tp.8
index 2df7ce2..463878f 100644
--- a/man/man8/ip-l2tp.8
+++ b/man/man8/ip-l2tp.8
@@ -52,6 +52,8 @@
.IR HEXSTR
.RB " ]"
.br
+.RB "[ " l2spec_type " { " none " | " default " } ]"
+.br
.RB "[ " offset
.IR OFFSET
.RB " ] [ " peer_offset
@@ -239,6 +241,12 @@
the peer. It tells the local system what cookie value to expect to
find in received L2TP packets. Default is to use no cookie.
.TP
+.BI l2spec_type " L2SPECTYPE"
+set the layer2specific header type of the session.
+.br
+Valid values are:
+.BR none ", " udp "."
+.TP
.BI offset " OFFSET"
sets the byte offset from the L2TP header where user data starts in
transmitted L2TP data packets. This is hardly ever used. If set, the
@@ -368,6 +376,12 @@
link failures in order to automate tearing down and reestablishing
dynamic tunnels. If a non-Linux peer supports Hello messages in
unmanaged tunnels, it must be turned off to interoperate with Linux.
+.PP
+Linux defaults to use the Default Layer2SpecificHeader type as defined
+in the L2TPv3 protocol specification, RFC3931. This setting must be
+consistent with that configured at the peer. Some vendor
+implementations (e.g. Cisco) default to use a Layer2SpecificHeader
+type of None.
.SH SEE ALSO
.br
.BR ip (8)
