1# SPDX-License-Identifier: GPL-2.0-only
  2#
  3# Layer Two Tunneling Protocol (L2TP)
  4#
  5
  6menuconfig L2TP
  7	tristate "Layer Two Tunneling Protocol (L2TP)"
  8	depends on (IPV6 || IPV6=n)
  9	depends on INET
 10	select NET_UDP_TUNNEL
 11	help
 12	  Layer Two Tunneling Protocol
 13
 14	  From RFC 2661 <http://www.ietf.org/rfc/rfc2661.txt>.
 15
 16	  L2TP facilitates the tunneling of packets across an
 17	  intervening network in a way that is as transparent as
 18	  possible to both end-users and applications.
 19
 20	  L2TP is often used to tunnel PPP traffic over IP
 21	  tunnels. One IP tunnel may carry thousands of individual PPP
 22	  connections. L2TP is also used as a VPN protocol, popular
 23	  with home workers to connect to their offices.
 24
 25	  L2TPv3 allows other protocols as well as PPP to be carried
 26	  over L2TP tunnels. L2TPv3 is defined in RFC 3931
 27	  <http://www.ietf.org/rfc/rfc3931.txt>.
 28
 29	  The kernel component handles only L2TP data packets: a
 30	  userland daemon handles L2TP the control protocol (tunnel
 31	  and session setup). One such daemon is OpenL2TP
 32	  (http://openl2tp.org/).
 33
 34	  If you don't need L2TP, say N. To compile all L2TP code as
 35	  modules, choose M here.
 36
 37config L2TP_DEBUGFS
 38	tristate "L2TP debugfs support"
 39	depends on L2TP && DEBUG_FS
 40	help
 41	  Support for l2tp directory in debugfs filesystem. This may be
 42	  used to dump internal state of the l2tp drivers for problem
 43	  analysis.
 44
 45	  If unsure, say 'Y'.
 46
 47	  To compile this driver as a module, choose M here. The module
 48	  will be called l2tp_debugfs.
 49
 50config L2TP_V3
 51	bool "L2TPv3 support"
 52	depends on L2TP
 53	help
 54	  Layer Two Tunneling Protocol Version 3
 55
 56	  From RFC 3931 <http://www.ietf.org/rfc/rfc3931.txt>.
 57
 58	  The Layer Two Tunneling Protocol (L2TP) provides a dynamic
 59	  mechanism for tunneling Layer 2 (L2) "circuits" across a
 60	  packet-oriented data network (e.g., over IP).  L2TP, as
 61	  originally defined in RFC 2661, is a standard method for
 62	  tunneling Point-to-Point Protocol (PPP) [RFC1661] sessions.
 63	  L2TP has since been adopted for tunneling a number of other
 64	  L2 protocols, including ATM, Frame Relay, HDLC and even raw
 65	  ethernet frames.
 66
 67	  If you are connecting to L2TPv3 equipment, or you want to
 68	  tunnel raw ethernet frames using L2TP, say Y here. If
 69	  unsure, say N.
 70
 71config L2TP_IP
 72	tristate "L2TP IP encapsulation for L2TPv3"
 73	depends on L2TP_V3
 74	help
 75	  Support for L2TP-over-IP socket family.
 76
 77	  The L2TPv3 protocol defines two possible encapsulations for
 78	  L2TP frames, namely UDP and plain IP (without UDP). This
 79	  driver provides a new L2TPIP socket family with which
 80	  userspace L2TPv3 daemons may create L2TP/IP tunnel sockets
 81	  when UDP encapsulation is not required. When L2TP is carried
 82	  in IP packets, it used IP protocol number 115, so this port
 83	  must be enabled in firewalls.
 84
 85	  To compile this driver as a module, choose M here. The module
 86	  will be called l2tp_ip.
 87
 88config L2TP_ETH
 89	tristate "L2TP ethernet pseudowire support for L2TPv3"
 90	depends on L2TP_V3
 91	help
 92	  Support for carrying raw ethernet frames over L2TPv3.
 93
 94	  From RFC 4719 <http://www.ietf.org/rfc/rfc4719.txt>.
 95
 96	  The Layer 2 Tunneling Protocol, Version 3 (L2TPv3) can be
 97	  used as a control protocol and for data encapsulation to set
 98	  up Pseudowires for transporting layer 2 Packet Data Units
 99	  across an IP network [RFC3931].
100
101	  This driver provides an ethernet virtual interface for each
102	  L2TP ethernet pseudowire instance. Standard Linux tools may
103	  be used to assign an IP address to the local virtual
104	  interface, or add the interface to a bridge.
105
106	  If you are using L2TPv3, you will almost certainly want to
107	  enable this option.
108
109	  To compile this driver as a module, choose M here. The module
110	  will be called l2tp_eth.