1 # SPDX-License-Identifier: GPL-2.0-only <<
2 # 1 #
3 # Layer Two Tunneling Protocol (L2TP) 2 # Layer Two Tunneling Protocol (L2TP)
4 # 3 #
5 4
6 menuconfig L2TP 5 menuconfig L2TP
7 tristate "Layer Two Tunneling Protocol 6 tristate "Layer Two Tunneling Protocol (L2TP)"
8 depends on (IPV6 || IPV6=n) 7 depends on (IPV6 || IPV6=n)
9 depends on INET 8 depends on INET
10 select NET_UDP_TUNNEL 9 select NET_UDP_TUNNEL
11 help !! 10 ---help---
12 Layer Two Tunneling Protocol 11 Layer Two Tunneling Protocol
13 12
14 From RFC 2661 <http://www.ietf.org/r 13 From RFC 2661 <http://www.ietf.org/rfc/rfc2661.txt>.
15 14
16 L2TP facilitates the tunneling of pa 15 L2TP facilitates the tunneling of packets across an
17 intervening network in a way that is 16 intervening network in a way that is as transparent as
18 possible to both end-users and appli 17 possible to both end-users and applications.
19 18
20 L2TP is often used to tunnel PPP tra 19 L2TP is often used to tunnel PPP traffic over IP
21 tunnels. One IP tunnel may carry tho 20 tunnels. One IP tunnel may carry thousands of individual PPP
22 connections. L2TP is also used as a 21 connections. L2TP is also used as a VPN protocol, popular
23 with home workers to connect to thei 22 with home workers to connect to their offices.
24 23
25 L2TPv3 allows other protocols as wel 24 L2TPv3 allows other protocols as well as PPP to be carried
26 over L2TP tunnels. L2TPv3 is defined 25 over L2TP tunnels. L2TPv3 is defined in RFC 3931
27 <http://www.ietf.org/rfc/rfc3931.txt 26 <http://www.ietf.org/rfc/rfc3931.txt>.
28 27
29 The kernel component handles only L2 28 The kernel component handles only L2TP data packets: a
30 userland daemon handles L2TP the con 29 userland daemon handles L2TP the control protocol (tunnel
31 and session setup). One such daemon 30 and session setup). One such daemon is OpenL2TP
32 (http://openl2tp.org/). 31 (http://openl2tp.org/).
33 32
34 If you don't need L2TP, say N. To co 33 If you don't need L2TP, say N. To compile all L2TP code as
35 modules, choose M here. 34 modules, choose M here.
36 35
37 config L2TP_DEBUGFS 36 config L2TP_DEBUGFS
38 tristate "L2TP debugfs support" 37 tristate "L2TP debugfs support"
39 depends on L2TP && DEBUG_FS 38 depends on L2TP && DEBUG_FS
40 help 39 help
41 Support for l2tp directory in debugf 40 Support for l2tp directory in debugfs filesystem. This may be
42 used to dump internal state of the l 41 used to dump internal state of the l2tp drivers for problem
43 analysis. 42 analysis.
44 43
45 If unsure, say 'Y'. 44 If unsure, say 'Y'.
46 45
47 To compile this driver as a module, 46 To compile this driver as a module, choose M here. The module
48 will be called l2tp_debugfs. 47 will be called l2tp_debugfs.
49 48
50 config L2TP_V3 49 config L2TP_V3
51 bool "L2TPv3 support" 50 bool "L2TPv3 support"
52 depends on L2TP 51 depends on L2TP
53 help 52 help
54 Layer Two Tunneling Protocol Version 53 Layer Two Tunneling Protocol Version 3
55 54
56 From RFC 3931 <http://www.ietf.org/r 55 From RFC 3931 <http://www.ietf.org/rfc/rfc3931.txt>.
57 56
58 The Layer Two Tunneling Protocol (L2 57 The Layer Two Tunneling Protocol (L2TP) provides a dynamic
59 mechanism for tunneling Layer 2 (L2) 58 mechanism for tunneling Layer 2 (L2) "circuits" across a
60 packet-oriented data network (e.g., 59 packet-oriented data network (e.g., over IP). L2TP, as
61 originally defined in RFC 2661, is a 60 originally defined in RFC 2661, is a standard method for
62 tunneling Point-to-Point Protocol (P 61 tunneling Point-to-Point Protocol (PPP) [RFC1661] sessions.
63 L2TP has since been adopted for tunn 62 L2TP has since been adopted for tunneling a number of other
64 L2 protocols, including ATM, Frame R 63 L2 protocols, including ATM, Frame Relay, HDLC and even raw
65 ethernet frames. 64 ethernet frames.
66 65
67 If you are connecting to L2TPv3 equi 66 If you are connecting to L2TPv3 equipment, or you want to
68 tunnel raw ethernet frames using L2T 67 tunnel raw ethernet frames using L2TP, say Y here. If
69 unsure, say N. 68 unsure, say N.
70 69
71 config L2TP_IP 70 config L2TP_IP
72 tristate "L2TP IP encapsulation for L2 71 tristate "L2TP IP encapsulation for L2TPv3"
73 depends on L2TP_V3 72 depends on L2TP_V3
74 help 73 help
75 Support for L2TP-over-IP socket fami 74 Support for L2TP-over-IP socket family.
76 75
77 The L2TPv3 protocol defines two poss 76 The L2TPv3 protocol defines two possible encapsulations for
78 L2TP frames, namely UDP and plain IP 77 L2TP frames, namely UDP and plain IP (without UDP). This
79 driver provides a new L2TPIP socket 78 driver provides a new L2TPIP socket family with which
80 userspace L2TPv3 daemons may create 79 userspace L2TPv3 daemons may create L2TP/IP tunnel sockets
81 when UDP encapsulation is not requir 80 when UDP encapsulation is not required. When L2TP is carried
82 in IP packets, it used IP protocol n 81 in IP packets, it used IP protocol number 115, so this port
83 must be enabled in firewalls. 82 must be enabled in firewalls.
84 83
85 To compile this driver as a module, 84 To compile this driver as a module, choose M here. The module
86 will be called l2tp_ip. 85 will be called l2tp_ip.
87 86
88 config L2TP_ETH 87 config L2TP_ETH
89 tristate "L2TP ethernet pseudowire sup 88 tristate "L2TP ethernet pseudowire support for L2TPv3"
90 depends on L2TP_V3 89 depends on L2TP_V3
91 help 90 help
92 Support for carrying raw ethernet fr 91 Support for carrying raw ethernet frames over L2TPv3.
93 92
94 From RFC 4719 <http://www.ietf.org/r 93 From RFC 4719 <http://www.ietf.org/rfc/rfc4719.txt>.
95 94
96 The Layer 2 Tunneling Protocol, Vers 95 The Layer 2 Tunneling Protocol, Version 3 (L2TPv3) can be
97 used as a control protocol and for d 96 used as a control protocol and for data encapsulation to set
98 up Pseudowires for transporting laye 97 up Pseudowires for transporting layer 2 Packet Data Units
99 across an IP network [RFC3931]. 98 across an IP network [RFC3931].
100 99
101 This driver provides an ethernet vir 100 This driver provides an ethernet virtual interface for each
102 L2TP ethernet pseudowire instance. S 101 L2TP ethernet pseudowire instance. Standard Linux tools may
103 be used to assign an IP address to t 102 be used to assign an IP address to the local virtual
104 interface, or add the interface to a 103 interface, or add the interface to a bridge.
105 104
106 If you are using L2TPv3, you will al 105 If you are using L2TPv3, you will almost certainly want to
107 enable this option. 106 enable this option.
108 107
109 To compile this driver as a module, 108 To compile this driver as a module, choose M here. The module
110 will be called l2tp_eth. 109 will be called l2tp_eth.
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