1# SPDX-License-Identifier: GPL-2.0-only
  2#
  3# PPP network device configuration
  4#
  5
  6config PPP
  7	tristate "PPP (point-to-point protocol) support"
  8	select SLHC
  9	help
 10	  PPP (Point to Point Protocol) is a newer and better SLIP.  It serves
 11	  the same purpose: sending Internet traffic over telephone (and other
 12	  serial) lines.  Ask your access provider if they support it, because
 13	  otherwise you can't use it; most Internet access providers these
 14	  days support PPP rather than SLIP.
 15
 16	  To use PPP, you need an additional program called pppd as described
 17	  in the PPP-HOWTO, available at
 18	  <http://www.tldp.org/docs.html#howto>.  Make sure that you have
 19	  the version of pppd recommended in <file:Documentation/Changes>.
 20	  The PPP option enlarges your kernel by about 16 KB.
 21
 22	  There are actually two versions of PPP: the traditional PPP for
 23	  asynchronous lines, such as regular analog phone lines, and
 24	  synchronous PPP which can be used over digital ISDN lines for
 25	  example.  If you want to use PPP over phone lines or other
 26	  asynchronous serial lines, you need to say Y (or M) here and also to
 27	  the next option, "PPP support for async serial ports".  For PPP over
 28	  synchronous lines, you should say Y (or M) here and to "Support
 29	  synchronous PPP", below.
 30
 31	  If you said Y to "Version information on all symbols" above, then
 32	  you cannot compile the PPP driver into the kernel; you can then only
 33	  compile it as a module. To compile this driver as a module, choose M
 34	  here. The module will be called ppp_generic.
 35
 36if PPP
 37
 38config PPP_BSDCOMP
 39	tristate "PPP BSD-Compress compression"
 40	depends on PPP
 41	help
 42	  Support for the BSD-Compress compression method for PPP, which uses
 43	  the LZW compression method to compress each PPP packet before it is
 44	  sent over the wire. The machine at the other end of the PPP link
 45	  (usually your ISP) has to support the BSD-Compress compression
 46	  method as well for this to be useful. Even if they don't support it,
 47	  it is safe to say Y here.
 48
 49	  The PPP Deflate compression method ("PPP Deflate compression",
 50	  above) is preferable to BSD-Compress, because it compresses better
 51	  and is patent-free.
 52
 53	  Note that the BSD compression code will always be compiled as a
 54	  module; it is called bsd_comp and will show up in the directory
 55	  modules once you have said "make modules". If unsure, say N.
 56
 57config PPP_DEFLATE
 58	tristate "PPP Deflate compression"
 59	depends on PPP
 60	select ZLIB_INFLATE
 61	select ZLIB_DEFLATE
 62	help
 63	  Support for the Deflate compression method for PPP, which uses the
 64	  Deflate algorithm (the same algorithm that gzip uses) to compress
 65	  each PPP packet before it is sent over the wire.  The machine at the
 66	  other end of the PPP link (usually your ISP) has to support the
 67	  Deflate compression method as well for this to be useful.  Even if
 68	  they don't support it, it is safe to say Y here.
 69
 70	  To compile this driver as a module, choose M here.
 71
 72config PPP_FILTER
 73	bool "PPP filtering"
 74	depends on PPP
 75	help
 76	  Say Y here if you want to be able to filter the packets passing over
 77	  PPP interfaces.  This allows you to control which packets count as
 78	  activity (i.e. which packets will reset the idle timer or bring up
 79	  a demand-dialed link) and which packets are to be dropped entirely.
 80	  You need to say Y here if you wish to use the pass-filter and
 81	  active-filter options to pppd.
 82
 83	  If unsure, say N.
 84
 85config PPP_MPPE
 86	tristate "PPP MPPE compression (encryption)"
 87	depends on PPP
 88	select CRYPTO
 89	select CRYPTO_SHA1
 90	select CRYPTO_LIB_ARC4
 91	help
 92	  Support for the MPPE Encryption protocol, as employed by the
 93	  Microsoft Point-to-Point Tunneling Protocol.
 94
 95	  See http://pptpclient.sourceforge.net/ for information on
 96	  configuring PPTP clients and servers to utilize this method.
 97
 98config PPP_MULTILINK
 99	bool "PPP multilink support"
100	depends on PPP
101	help
102	  PPP multilink is a protocol (defined in RFC 1990) which allows you
103	  to combine several (logical or physical) lines into one logical PPP
104	  connection, so that you can utilize your full bandwidth.
105
106	  This has to be supported at the other end as well and you need a
107	  version of the pppd daemon which understands the multilink protocol.
108
109	  If unsure, say N.
110
111config PPPOATM
112	tristate "PPP over ATM"
113	depends on ATM && PPP
114	help
115	  Support PPP (Point to Point Protocol) encapsulated in ATM frames.
116	  This implementation does not yet comply with section 8 of RFC2364,
117	  which can lead to bad results if the ATM peer loses state and
118	  changes its encapsulation unilaterally.
119
120config PPPOE
121	tristate "PPP over Ethernet"
122	depends on PPP
123	help
124	  Support for PPP over Ethernet.
125
126	  This driver requires the latest version of pppd from the CVS
127	  repository at cvs.samba.org.  Alternatively, see the
128	  RoaringPenguin package (<http://www.roaringpenguin.com/pppoe>)
129	  which contains instruction on how to use this driver (under
130	  the heading "Kernel mode PPPoE").
131
132choice
133	prompt "Number of PPPoE hash bits"
134	default PPPOE_HASH_BITS_4
135	depends on PPPOE
136	help
137		Select the number of bits used for hashing PPPoE interfaces.
138
139		Larger sizes reduces the risk of hash collisions at the cost
140		of slightly increased memory usage.
141
142		This hash table is on a per outer ethernet interface.
143
144config PPPOE_HASH_BITS_1
145	bool "1 bit (2 buckets)"
146
147config PPPOE_HASH_BITS_2
148	bool "2 bits (4 buckets)"
149
150config PPPOE_HASH_BITS_4
151	bool "4 bits (16 buckets)"
152
153config PPPOE_HASH_BITS_8
154	bool "8 bits (256 buckets)"
155
156endchoice
157
158config PPPOE_HASH_BITS
159	int
160	default 1 if PPPOE_HASH_BITS_1
161	default 2 if PPPOE_HASH_BITS_2
162	default 4 if PPPOE_HASH_BITS_4
163	default 8 if PPPOE_HASH_BITS_8
164	default 4
165
166config PPTP
167	tristate "PPP over IPv4 (PPTP)"
168	depends on PPP && NET_IPGRE_DEMUX
169	help
170	  Support for PPP over IPv4.(Point-to-Point Tunneling Protocol)
171
172	  This driver requires pppd plugin to work in client mode or
173	  modified pptpd (poptop) to work in server mode.
174	  See http://accel-pptp.sourceforge.net/ for information how to
175	  utilize this module.
176
177config PPPOL2TP
178	tristate "PPP over L2TP"
179	depends on L2TP && PPP
180	help
181	  Support for PPP-over-L2TP socket family. L2TP is a protocol
182	  used by ISPs and enterprises to tunnel PPP traffic over UDP
183	  tunnels. L2TP is replacing PPTP for VPN uses.
184if TTY
185
186config PPP_ASYNC
187	tristate "PPP support for async serial ports"
188	depends on PPP
189	select CRC_CCITT
190	help
191	  Say Y (or M) here if you want to be able to use PPP over standard
192	  asynchronous serial ports, such as COM1 or COM2 on a PC.  If you use
193	  a modem (not a synchronous or ISDN modem) to contact your ISP, you
194	  need this option.
195
196	  To compile this driver as a module, choose M here.
197
198	  If unsure, say Y.
199
200config PPP_SYNC_TTY
201	tristate "PPP support for sync tty ports"
202	depends on PPP
203	help
204	  Say Y (or M) here if you want to be able to use PPP over synchronous
205	  (HDLC) tty devices, such as the SyncLink adapter. These devices
206	  are often used for high-speed leased lines like T1/E1.
207
208	  To compile this driver as a module, choose M here.
209
210endif # TTY
211
212endif # PPP