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1 | secnet - flexible VPN software |
2 | ||
8dea8d37 SE |
3 | * Copying |
4 | ||
5 | secnet is Copyright (C) 1995--2001 Stephen Early <steve@greenend.org.uk> | |
6 | It is distributed under the terms of the GNU General Public License, | |
7 | version 2 or later. See the file COPYING for more information. | |
8 | ||
9 | The portable snprintf implementation in snprintf.c is Copyright (C) | |
10 | 1999 Mark Martinec <mark.martinec@ijs.si> and is distributed under the | |
11 | terms of the Frontier Artistic License. You can find the standard | |
12 | version of snprintf.c at http://www.ijs.si/software/snprintf/ | |
13 | ||
14 | The IP address handling library in ipaddr.py is Copyright (C) | |
15 | 1996--2000 Cendio Systems AB, and is distributed under the terms of | |
16 | the GPL. | |
17 | ||
558fa3fb SE |
18 | * Introduction |
19 | ||
20 | secnet allows large virtual private networks to be constructed | |
21 | spanning multiple separate sites. It is designed for the case where a | |
22 | private network connecting many hosts is 'hidden' behind a single | |
23 | globally-routable IP address, but can also be applied in other | |
24 | circumstances. It communicates entirely using UDP, and works well | |
25 | with gateways that implement network address translation. | |
26 | ||
27 | If you are installing secnet to join an existing VPN, you should read | |
28 | the 'INSTALL' file and your particular VPN's documentation now. You | |
29 | may need to refer back to this file for information on the netlink and | |
30 | comm sections of the configuration file. | |
31 | ||
32 | If you are thinking about setting up a new VPN of any size (from one | |
33 | providing complete links between multiple sites to a simple | |
34 | laptop-to-host link), read the section in this file on 'Creating a | |
35 | VPN'. | |
36 | ||
37 | * Creating a VPN | |
38 | ||
39 | XXX TODO | |
40 | ||
41 | * secnet configuration file format | |
42 | ||
43 | By default secnet on linux reads /etc/secnet/secnet.conf. The default | |
44 | may be different on other platforms. | |
45 | ||
46 | This file defines a dictionary (a mapping from keys to values) full of | |
47 | configuration information for secnet. Two keys must be defined in | |
48 | this file for secnet to start. One is "system", a dictionary | |
49 | containing systemwide control parameters. The other is "sites", a | |
50 | list of all the sites that you intend to communicate with. | |
51 | ||
52 | The configuration file has a very simple syntax; keys are defined as | |
53 | follows: | |
54 | ||
55 | key definition; | |
56 | or | |
57 | key = definition; | |
58 | ||
59 | (the "=" is optional) | |
60 | ||
61 | Keys must match the following regular expression: | |
62 | [[:alpha:]_][[:alnum:]\-_]* | |
63 | ||
64 | i.e. the first character must be an alpha or an underscore, and the | |
65 | remaining characters may be alphanumeric, '-' or '_'. | |
66 | ||
67 | Keys can be defined to be a comma-separated list of any of the | |
68 | following types: | |
69 | ||
70 | a boolean | |
71 | a string, in quotes | |
72 | a number, in decimal | |
73 | a dictionary of definitions, enclosed in { } | |
74 | a "closure", followed by arguments | |
75 | a path to a key that already exists, to reference that definition | |
76 | ||
77 | Note that dictionaries can be nested: a key in one dictionary can | |
78 | refer to another dictionary. When secnet looks for a key in a | |
79 | particular directory and can't find it, it looks in the dictionary's | |
80 | lexical 'parents' in turn until it finds it (or fails to find it at | |
81 | all and stops with an error). | |
82 | ||
83 | Definitions can refer to previous definitions by naming them with a | |
84 | path. Paths are key1/key2/key3... (starting from wherever we find | |
85 | key1, i.e. in the current dictionary or any of its parents), or | |
86 | alternatively /key1/key2/key3... (to start from the root). | |
87 | Definitions cannot refer to future definitions. | |
88 | ||
89 | Example: | |
90 | ||
91 | a=1; | |
92 | b=2; | |
93 | c={ d=3; e=a; }; | |
94 | f={ a=4; g=c; }; | |
95 | ||
96 | The following paths are valid: | |
97 | a is 1 | |
98 | b is 2 | |
99 | c is a dictionary: | |
100 | c/d is 3 | |
101 | c/e is 1 | |
102 | f is a dictionary: | |
103 | f/a is 4 | |
104 | f/g is a dictionary: | |
105 | f/g/d is 3 | |
106 | f/g/e is 1 | |
107 | ||
108 | Note that f/g/e is NOT 4. | |
109 | ||
110 | In a future version of secnet it will also be permissible to list | |
111 | other dictionaries before a dictionary definition, | |
112 | eg. <defaults,otherdefaults>{definitions}. These will be searched in | |
113 | order for keys, before the lexical parent. (This is not yet | |
114 | implemented) | |
115 | ||
116 | Elements that are lists are inserted into lists in definitions, not | |
117 | referenced by them (i.e. you can't have lists of lists). | |
118 | ||
119 | Some closures may be followed by an argument list in ( ), and may | |
120 | return any number of whatever type they like (including other | |
121 | closures). Some types of closure (typically those returned from | |
122 | invokations of other closures) cannot be invoked. | |
123 | ||
124 | closure { definitions } is short for closure({definitions}). | |
125 | ||
126 | The main body of secnet, and all the additional modules, predefine | |
127 | some keys in the root dictionary. The main ones are: | |
128 | ||
129 | yes, true, True, TRUE: the boolean value True | |
130 | no, false, False, FALSE: the boolean value False | |
131 | makelist: turns a dictionary (arg1) into a list of definitions | |
132 | (ignoring the keys) | |
133 | readfile: reads a file (arg1) and returns it as a string | |
134 | ||
135 | Keys defined by modules are described below, in the module | |
136 | documentation. | |
137 | ||
138 | Other configuration files can be included inline by writing "include | |
139 | filename" at the start of a line. | |
140 | ||
141 | After the configuration file is read, secnet looks for particular keys | |
142 | in configuration space to tell it what to do: | |
143 | ||
144 | system: a dictionary which can contain the following keys: | |
145 | log (log closure): a destination for system messages | |
146 | userid (string): the userid for secnet to run as once it drops privileges | |
147 | pidfile (string): where to store its PID | |
148 | ||
149 | sites: a list of closures of type 'site', which define other tunnel | |
150 | endpoints that secnet will attempt to communicate with | |
151 | ||
152 | * secnet command line options | |
153 | ||
154 | XXX TODO | |
155 | ||
156 | * secnet builtin modules | |
157 | ||
158 | ** resolver | |
159 | ||
160 | Defines: | |
161 | adns (closure => resolver closure) | |
162 | ||
3454dce4 SE |
163 | adns: dict argument |
164 | config (string): optional, a resolv.conf for ADNS to use | |
165 | ||
558fa3fb SE |
166 | ** random |
167 | ||
168 | Defines: | |
169 | randomsrc (closure => randomsrc closure) | |
170 | ||
3454dce4 SE |
171 | randomsrc: string[,bool] |
172 | arg1: filename of random source | |
173 | arg2: if True then source is blocking | |
174 | ||
558fa3fb SE |
175 | ** udp |
176 | ||
177 | Defines: | |
178 | udp (closure => comm closure) | |
179 | ||
3454dce4 SE |
180 | udp: dict argument |
181 | port (integer): UDP port to listen and send on | |
182 | buffer (buffer closure): buffer for incoming packets | |
b2a56f7c | 183 | authbind (string): optional, path to authbind-helper program |
3454dce4 | 184 | |
042a8da9 | 185 | ** log |
558fa3fb SE |
186 | |
187 | Defines: | |
188 | logfile (closure => log closure) | |
b2a56f7c | 189 | syslog (closure => log closure) |
558fa3fb | 190 | |
b2a56f7c SE |
191 | logfile: dict argument |
192 | filename (string): where to log to | |
193 | class (string list): what type of messages to log | |
194 | { "debug-config", M_DEBUG_CONFIG }, | |
195 | { "debug-phase", M_DEBUG_PHASE }, | |
196 | { "debug", M_DEBUG }, | |
197 | { "all-debug", M_DEBUG|M_DEBUG_PHASE|M_DEBUG_CONFIG }, | |
198 | { "info", M_INFO }, | |
199 | { "notice", M_NOTICE }, | |
200 | { "warning", M_WARNING }, | |
201 | { "error", M_ERROR }, | |
202 | { "security", M_SECURITY }, | |
203 | { "fatal", M_FATAL }, | |
204 | { "default", M_WARNING|M_ERROR|M_SECURITY|M_FATAL }, | |
205 | { "verbose", M_INFO|M_NOTICE|M_WARNING|M_ERROR|M_SECURITY|M_FATAL }, | |
206 | { "quiet", M_FATAL } | |
207 | ||
042a8da9 SE |
208 | logfile will close and reopen its file upon receipt of SIGHUP. |
209 | ||
b2a56f7c SE |
210 | syslog: dict argument |
211 | ident (string): include this string in every log message | |
212 | facility (string): facility to log as | |
213 | { "authpriv", LOG_AUTHPRIV }, | |
214 | { "cron", LOG_CRON }, | |
215 | { "daemon", LOG_DAEMON }, | |
216 | { "kern", LOG_KERN }, | |
217 | { "local0", LOG_LOCAL0 }, | |
218 | { "local1", LOG_LOCAL1 }, | |
219 | { "local2", LOG_LOCAL2 }, | |
220 | { "local3", LOG_LOCAL3 }, | |
221 | { "local4", LOG_LOCAL4 }, | |
222 | { "local5", LOG_LOCAL5 }, | |
223 | { "local6", LOG_LOCAL6 }, | |
224 | { "local7", LOG_LOCAL7 }, | |
225 | { "lpr", LOG_LPR }, | |
226 | { "mail", LOG_MAIL }, | |
227 | { "news", LOG_NEWS }, | |
228 | { "syslog", LOG_SYSLOG }, | |
229 | { "user", LOG_USER }, | |
230 | { "uucp", LOG_UUCP } | |
231 | ||
042a8da9 SE |
232 | ** util |
233 | ||
234 | Defines: | |
235 | sysbuffer (closure => buffer closure) | |
236 | ||
b2a56f7c SE |
237 | sysbuffer: integer[,dict] |
238 | arg1: buffer length | |
239 | arg2: options: | |
240 | lockdown (boolean): if True, mlock() the buffer | |
241 | ||
558fa3fb SE |
242 | ** site |
243 | ||
244 | Defines: | |
245 | site (closure => site closure) | |
246 | ||
3454dce4 SE |
247 | site: dict argument |
248 | local-name (string): this site's name for itself | |
249 | name (string): the name of the site's peer | |
250 | netlink (netlink closure) | |
251 | comm (comm closure) | |
252 | resolver (resolver closure) | |
253 | random (randomsrc closure) | |
254 | local-key (rsaprivkey closure) | |
255 | address (string): optional, DNS name used to find our peer | |
256 | port (integer): mandatory if 'address' is specified: the port used | |
257 | to contact our peer | |
258 | networks (string list): networks that our peer may claim traffic for | |
259 | key (rsapubkey closure): our peer's public key | |
260 | transform (transform closure): how to mangle packets sent between sites | |
261 | dh (dh closure) | |
262 | hash (hash closure) | |
263 | key-lifetime (integer): max lifetime of a session key, in ms [one hour] | |
264 | setup-retries (integer): max number of times to transmit a key negotiation | |
265 | packet [5] | |
266 | setup-timeout (integer): time between retransmissions of key negotiation | |
267 | packets, in ms [1000] | |
268 | wait-time (integer): after failed key setup, wait this long (in ms) before | |
269 | allowing another attempt [20000] | |
270 | renegotiate-time (integer): if we see traffic on the link after this time | |
271 | then renegotiate another session key immediately [depends on key-lifetime] | |
272 | keepalive (bool): if True then attempt always to keep a valid session key | |
273 | log-events (string list): types of events to log for this site | |
274 | unexpected: unexpected key setup packets (may be late retransmissions) | |
275 | setup-init: start of attempt to setup a session key | |
276 | setup-timeout: failure of attempt to setup a session key, through timeout | |
277 | activate-key: activation of a new session key | |
278 | timeout-key: deletion of current session key through age | |
279 | security: anything potentially suspicious | |
280 | state-change: steps in the key setup protocol | |
281 | packet-drop: whenever we throw away an outgoing packet | |
282 | dump-packets: every key setup packet we see | |
283 | errors: failure of name resolution, internal errors | |
284 | all: everything (too much!) | |
285 | netlink-options (string list): options to pass to netlink device when | |
286 | registering remote networks | |
287 | soft: create 'soft' routes that go away when there's no key established | |
288 | with the peer | |
289 | allow-route: allow packets from our peer to be sent down other tunnels, | |
290 | as well as to the host | |
291 | ||
558fa3fb SE |
292 | ** transform |
293 | ||
294 | Defines: | |
295 | serpent256-cbc (closure => transform closure) | |
296 | ||
297 | ** netlink | |
298 | ||
299 | Defines: | |
3454dce4 SE |
300 | null-netlink (closure => netlink closure) |
301 | ||
302 | null-netlink: dict argument | |
303 | name (string): name for netlink device, used in log messages | |
304 | networks (string list): networks on the host side of the netlink device | |
305 | exclude-remote-networks (string list): networks that may never be claimed | |
306 | by any remote site using this netlink device | |
307 | local-address (string): IP address of host's tunnel interface | |
308 | secnet-address (string): IP address of this netlink device | |
c6f79b17 | 309 | ptp-address (string): IP address of the other end of a point-to-point link |
3454dce4 SE |
310 | mtu (integer): MTU of host's tunnel interface |
311 | ||
c6f79b17 SE |
312 | Only one of secnet-address or ptp-address may be specified. If |
313 | point-to-point mode is in use then precisely one tunnel must register | |
314 | with the netlink device. | |
315 | ||
042a8da9 SE |
316 | Netlink will dump its current routing table to the system/log on |
317 | receipt of SIGUSR1. | |
318 | ||
3454dce4 SE |
319 | ** slip |
320 | ||
321 | Defines: | |
558fa3fb | 322 | userv-ipif (closure => netlink closure) |
3454dce4 SE |
323 | |
324 | userv-ipif: dict argument | |
325 | userv-path (string): optional, where to find userv ["userv"] | |
326 | service-user (string): optional, username for userv-ipif service ["root"] | |
327 | service-name (string): optional, name of userv-ipif service ["ipif"] | |
328 | buffer (buffer closure): buffer for assembly of host->secnet packets | |
329 | plus generic netlink options, as for 'null-netlink' | |
330 | ||
331 | ** tun | |
332 | ||
333 | Defines: | |
558fa3fb SE |
334 | tun (closure => netlink closure) [only on linux-2.4] |
335 | tun-old (closure => netlink closure) | |
3454dce4 SE |
336 | |
337 | tun: dict argument | |
338 | device (string): optional, path of TUN/TAP device file ["/dev/net/tun"] | |
339 | interface (string): optional, name of tunnel network interface | |
340 | ifconfig-path (string): optional, path to ifconfig command | |
341 | route-path (string): optional, path to route command | |
342 | buffer (buffer closure): buffer for host->secnet packets | |
343 | plus generic netlink options, as for 'null-netlink' | |
344 | ||
345 | tun-old: dict argument | |
346 | device (string): optional, path of TUN/TAP device file ["/dev/tun*"] | |
347 | interface (string): optional, name of tunnel network interface | |
348 | interface-search (bool): optional, whether to search for a free tunnel | |
349 | interface (True if 'device' not specified, otherwise False) | |
350 | ifconfig-path (string): optional, path to ifconfig command | |
351 | route-path (string): optional, path to route command | |
352 | plus generic netlink options, as for 'null-netlink' | |
558fa3fb | 353 | |
c6f79b17 SE |
354 | I recommend you don't specify the 'interface' option unless you're |
355 | doing something that requires the interface name to be constant. | |
356 | ||
558fa3fb SE |
357 | ** rsa |
358 | ||
359 | Defines: | |
360 | rsa-private (closure => rsaprivkey closure) | |
361 | rsa-public (closure => rsapubkey closure) | |
362 | ||
3454dce4 SE |
363 | rsa-private: string[,bool] |
364 | arg1: filename of SSH private key file (version 1, no password) | |
365 | arg2: whether to check that the key is usable [default True] | |
366 | ||
367 | rsa-public: string,string | |
368 | arg1: encryption key (decimal) | |
369 | arg2: modulus (decimal) | |
370 | ||
558fa3fb SE |
371 | ** dh |
372 | ||
373 | Defines: | |
374 | diffie-hellman (closure => dh closure) | |
375 | ||
3454dce4 SE |
376 | diffie-hellman: string,string[,bool] |
377 | arg1: modulus (hex) | |
378 | arg2: generator (hex) | |
379 | arg3: whether to check that the modulus is prime [default True] | |
380 | ||
558fa3fb SE |
381 | ** md5 |
382 | ||
383 | Defines: | |
384 | md5 (hash closure) | |
3454dce4 SE |
385 | |
386 | ** sha1 | |
387 | ||
388 | Defines: | |
389 | sha1 (hash closure) | |
c6f79b17 SE |
390 | |
391 | ** conffile | |
392 | ||
393 | Defines: | |
394 | makelist (dictionary => list of definitions) | |
395 | readfile (string => string) | |
396 | map (closure,list => list) | |
397 | ||
398 | makelist: dictionary | |
399 | returns a list consisting of the definitions in the dictionary. The keys | |
400 | are discarded. | |
401 | ||
402 | readfile: string | |
403 | reads the named file and returns its contents as a string | |
404 | ||
405 | map: | |
406 | applies the closure specified as arg1 to each of the elements in the list. | |
407 | Returns a list made up of the outputs of the closure. |