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