aboutsummaryrefslogtreecommitdiff
path: root/src/nat/gnunet-nat.c
blob: 04bde5111b39cab557355a8c74de56c1948f1cb2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
/*
     This file is part of GNUnet.
     Copyright (C) 2015, 2016 GNUnet e.V.

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file src/nat/gnunet-nat.c
 * @brief Command-line tool to interact with the NAT service
 * @author Christian Grothoff
 * @author Bruno Cabral
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_nat_service.h"

/**
 * Value to return from #main().
 */
static int global_ret;

/**
 * Name of section in configuration file to use for
 * additional options.
 */
static char *section_name;

/**
 * Flag set to 1 if we use IPPROTO_UDP.
 */
static int use_udp;

/**
 * Flag set to 1 if we are to listen for connection reversal requests.
 */
static int listen_reversal;

/**
 * Flag set to 1 if we use IPPROTO_TCP.
 */
static int use_tcp;

/**
 * Protocol to use.
 */
static uint8_t proto;

/**
 * Local address to use for connection reversal request.
 */
static char *local_addr;

/**
 * Remote address to use for connection reversal request.
 */
static char *remote_addr;

/**
 * Should we actually bind to #bind_addr and receive and process STUN requests?
 */
static unsigned int do_stun;

/**
 * Handle to NAT operation.
 */
static struct GNUNET_NAT_Handle *nh;

/**
 * Listen socket for STUN processing.
 */
static struct GNUNET_NETWORK_Handle *ls;

/**
 * Task for reading STUN packets.
 */
static struct GNUNET_SCHEDULER_Task *rtask;


/**
 * Test if all activities have finished, and if so,
 * terminate.
 */
static void
test_finished ()
{
  if (NULL != nh)
    return;
  if (NULL != rtask)
    return;
  GNUNET_SCHEDULER_shutdown ();
}


/**
 * Signature of the callback passed to #GNUNET_NAT_register() for
 * a function to call whenever our set of 'valid' addresses changes.
 *
 * @param cls closure, NULL
 * @param add_remove #GNUNET_YES to add a new public IP address,
 *                   #GNUNET_NO to remove a previous (now invalid) one
 * @param ac address class the address belongs to
 * @param addr either the previous or the new public IP address
 * @param addrlen actual length of the @a addr
 */
static void
address_cb (void *cls,
	    int add_remove,
	    enum GNUNET_NAT_AddressClass ac,
	    const struct sockaddr *addr,
	    socklen_t addrlen)
{
  fprintf (stdout,
           "%s %s (%d)\n",
           add_remove ? "+" : "-",
           GNUNET_a2s (addr,
                       addrlen),
           (int) ac);
}


/**
 * Signature of the callback passed to #GNUNET_NAT_register().
 * for a function to call whenever someone asks us to do connection
 * reversal.
 *
 * @param cls closure, NULL
 * @param remote_addr public IP address of the other peer
 * @param remote_addrlen actual length of the @a remote_addr
 */
static void
reversal_cb (void *cls,
	     const struct sockaddr *remote_addr,
	     socklen_t remote_addrlen)
{
  GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
	      "Connection reversal requested by %s\n",
	      GNUNET_a2s (remote_addr,
			  remote_addrlen));
}


/**
 * Task run on shutdown.
 *
 * @param cls NULL
 */
static void
do_shutdown (void *cls)
{
  if (NULL != nh)
  {
    GNUNET_NAT_unregister (nh);
    nh = NULL;
  }
  if (NULL != ls)
  {
    GNUNET_NETWORK_socket_close (ls);
    ls = NULL;
  }
  if (NULL != rtask)
  {
    GNUNET_SCHEDULER_cancel (rtask);
    rtask = NULL;
  }
}


/**
 * Task to receive incoming packets for STUN processing.
 */
static void
stun_read_task (void *cls)
{
  ssize_t size;

  rtask = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
					 ls,
					 &stun_read_task,
					 NULL);
  size = GNUNET_NETWORK_socket_recvfrom_amount (ls);
  if (size > 0)
  {
    GNUNET_break (0);
    GNUNET_SCHEDULER_shutdown ();
    global_ret = 1;
    return;
  }
  {
    char buf[size + 1];
    struct sockaddr_storage sa;
    socklen_t salen = sizeof (sa);
    ssize_t ret;

    ret = GNUNET_NETWORK_socket_recvfrom (ls,
					  buf,
					  size + 1,
					  (struct sockaddr *) &sa,
					  &salen);
    if (ret != size)
    {
      GNUNET_break (0);
      GNUNET_SCHEDULER_shutdown ();
      global_ret = 1;
      return;
    }
    (void) GNUNET_NAT_stun_handle_packet (nh,
					  (const struct sockaddr *) &sa,
					  salen,
					  buf,
					  ret);
  }
}


/**
 * Main function that will be run.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param c configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *c)
{
  uint8_t af;
  struct sockaddr *local_sa;
  struct sockaddr *remote_sa;
  socklen_t local_len;
  size_t remote_len;

  if (use_tcp && use_udp)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		"Cannot use TCP and UDP\n");
    global_ret = 1;
    return;
  }
  proto = 0;
  if (use_tcp)
    proto = IPPROTO_TCP;
  if (use_udp)
    proto = IPPROTO_UDP;

  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
				 NULL);

  if (0 == proto)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		"Must specify either TCP or UDP\n");
    global_ret = 1;
    return;
  }
  local_len = 0;
  local_sa = NULL;
  remote_len = 0;
  remote_sa = NULL;
  if (NULL != local_addr)
  {
    local_len = (socklen_t) GNUNET_STRINGS_parse_socket_addr (local_addr,
							      &af,
							      &local_sa);
    if (0 == local_len)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Invalid socket address `%s'\n",
		  local_addr);
      goto fail_and_shutdown;
    }
  }

  if (NULL != remote_addr)
  {
    remote_len = GNUNET_STRINGS_parse_socket_addr (remote_addr,
						   &af,
						   &remote_sa);
    if (0 == remote_len)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Invalid socket address `%s'\n",
		  remote_addr);
      goto fail_and_shutdown;
    }
  }

  if (NULL != local_addr)
  {
    if (NULL == section_name)
      section_name = GNUNET_strdup ("undefined");
    nh = GNUNET_NAT_register (c,
			      section_name,
			      proto,
			      1,
			      (const struct sockaddr **) &local_sa,
			      &local_len,
			      &address_cb,
			      (listen_reversal) ? &reversal_cb : NULL,
			      NULL);
  }
  else if (listen_reversal)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		"Use of `-W` only effective in combination with `-i`\n");
    goto fail_and_shutdown;
  }

  if (NULL != remote_addr)
  {
    int ret;

    if ( (NULL == nh) ||
	 (sizeof (struct sockaddr_in) != local_len) )
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Require IPv4 local address to initiate connection reversal\n");
      goto fail_and_shutdown;
    }
    if (sizeof (struct sockaddr_in) != remote_len)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Require IPv4 reversal target address\n");
      goto fail_and_shutdown;
    }
    GNUNET_assert (AF_INET == local_sa->sa_family);
    GNUNET_assert (AF_INET == remote_sa->sa_family);
    ret = GNUNET_NAT_request_reversal (nh,
				       (const struct sockaddr_in *) local_sa,
				       (const struct sockaddr_in *) remote_sa);
    switch (ret)
    {
    case GNUNET_SYSERR:
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Connection reversal internal error\n");
      break;
    case GNUNET_NO:
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Connection reversal unavailable\n");
      break;
    case GNUNET_OK:
      /* operation in progress */
      break;
    }
  }

  if (do_stun)
  {
    if (NULL == local_addr)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "Require local address to support STUN requests\n");
      goto fail_and_shutdown;
    }
    if (IPPROTO_UDP != proto)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_MESSAGE,
		  "STUN only supported over UDP\n");
      goto fail_and_shutdown;
    }
    ls = GNUNET_NETWORK_socket_create (af,
				       SOCK_DGRAM,
				       IPPROTO_UDP);
    if (GNUNET_OK !=
	GNUNET_NETWORK_socket_bind (ls,
				    local_sa,
				    local_len))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		  "Failed to bind to %s: %s\n",
		  GNUNET_a2s (local_sa,
			      local_len),
		  STRERROR (errno));
      goto fail_and_shutdown;
    }
    rtask = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
					   ls,
					   &stun_read_task,
					   NULL);
  }
  GNUNET_free_non_null (remote_sa);
  GNUNET_free_non_null (local_sa);
  test_finished ();
  return;
 fail_and_shutdown:
  global_ret = 1;
  GNUNET_SCHEDULER_shutdown ();
  GNUNET_free_non_null (remote_sa);
  GNUNET_free_non_null (local_sa);
}


/**
 * Main function of gnunet-nat
 *
 * @param argc number of command-line arguments
 * @param argv command line
 * @return 0 on success, -1 on error
 */
int
main (int argc,
      char *const argv[])
{
  static const struct GNUNET_GETOPT_CommandLineOption options[] = {
    {'i', "in", "ADDRESS",
     gettext_noop ("which IP and port are we locally using to bind/listen to"),
     GNUNET_YES, &GNUNET_GETOPT_set_string, &local_addr },
    {'r', "remote", "ADDRESS",
     gettext_noop ("which remote IP and port should be asked for connection reversal"),
     GNUNET_YES, &GNUNET_GETOPT_set_string, &remote_addr },
    {'S', "section", NULL,
     gettext_noop ("name of configuration section to find additional options, such as manual host punching data"),
     GNUNET_YES, &GNUNET_GETOPT_set_string, &section_name },
    {'s', "stun", NULL,
     gettext_noop ("enable STUN processing"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &do_stun },
    {'t', "tcp", NULL,
     gettext_noop ("use TCP"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &use_tcp },
    {'u', "udp", NULL,
     gettext_noop ("use UDP"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &use_udp },
    {'W', "watch", NULL,
     gettext_noop ("watch for connection reversal requests"),
     GNUNET_NO, &GNUNET_GETOPT_set_one, &listen_reversal },
   GNUNET_GETOPT_OPTION_END
  };

  if (GNUNET_OK !=
      GNUNET_STRINGS_get_utf8_args (argc, argv,
				    &argc, &argv))
    return 2;
  if (GNUNET_OK !=
      GNUNET_PROGRAM_run (argc, argv,
			  "gnunet-nat [options]",
                          _("GNUnet NAT traversal autoconfigure daemon"),
			  options,
                          &run,
			  NULL))
  {
    global_ret = 1;
  }
  GNUNET_free ((void*) argv);
  return global_ret;
}


/* end of gnunet-nat.c */