summaryrefslogtreecommitdiff
path: root/src/nat/gnunet-nat-server.c
blob: 66b5ee3dab7b46f02c11004ecf556581d8d3cabf (plain)
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
/*
     This file is part of GNUnet.
     Copyright (C) 2011 Christian Grothoff (and other contributing authors)

     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-server.c
 * @brief Daemon to run on 'gnunet.org' to help test NAT traversal code
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_nat_lib.h"
#include "gnunet_protocols.h"
#include "nat.h"


/**
 * Our server.
 */
static struct GNUNET_SERVER_Handle *server;

/**
 * Our configuration.
 */
static const struct GNUNET_CONFIGURATION_Handle *cfg;


/**
 * Try contacting the peer using autonomous
 * NAT traveral method.
 *
 * @param dst_ipv4 IPv4 address to send the fake ICMP message
 * @param dport destination port to include in ICMP message
 * @param is_tcp mark for TCP (GNUNET_YES)  or UDP (GNUNET_NO)
 */
static void
try_anat (uint32_t dst_ipv4, uint16_t dport, int is_tcp)
{
  struct GNUNET_NAT_Handle *h;
  struct sockaddr_in sa;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Asking for connection reversal with %x and code %u\n",
              (unsigned int) dst_ipv4, (unsigned int) dport);
  h = GNUNET_NAT_register (cfg, is_tcp, dport, 0, NULL, NULL, NULL, NULL, NULL, NULL);
  memset (&sa, 0, sizeof (sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = sizeof (sa);
#endif
  sa.sin_addr.s_addr = dst_ipv4;
  GNUNET_NAT_run_client (h, &sa);
  GNUNET_NAT_unregister (h);
}


/**
 * Closure for 'tcp_send'.
 */
struct TcpContext
{
  /**
   * TCP  socket.
   */
  struct GNUNET_NETWORK_Handle *s;

  /**
   * Data to transmit.
   */
  uint16_t data;
};


/**
 * Task called by the scheduler once we can do the TCP send
 * (or once we failed to connect...).
 *
 * @param cls the 'struct TcpContext'
 * @param tc scheduler context
 */
static void
tcp_send (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct TcpContext *ctx = cls;

  if ((NULL != tc->write_ready) &&
      (GNUNET_NETWORK_fdset_isset (tc->write_ready, ctx->s)))
  {
    if (-1 ==
        GNUNET_NETWORK_socket_send (ctx->s, &ctx->data, sizeof (ctx->data)))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "send");
    }
    GNUNET_NETWORK_socket_shutdown (ctx->s, SHUT_RDWR);
  }
  GNUNET_NETWORK_socket_close (ctx->s);
  GNUNET_free (ctx);
}


/**
 * Try to send 'data' to the
 * IP 'dst_ipv4' at port 'dport' via TCP.
 *
 * @param dst_ipv4 target IP
 * @param dport target port
 * @param data data to send
 */
static void
try_send_tcp (uint32_t dst_ipv4, uint16_t dport, uint16_t data)
{
  struct GNUNET_NETWORK_Handle *s;
  struct sockaddr_in sa;
  struct TcpContext *ctx;

  s = GNUNET_NETWORK_socket_create (AF_INET, SOCK_STREAM, 0);
  if (NULL == s)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "socket");
    return;
  }
  memset (&sa, 0, sizeof (sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = sizeof (sa);
#endif
  sa.sin_addr.s_addr = dst_ipv4;
  sa.sin_port = htons (dport);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending TCP message to `%s'\n",
              GNUNET_a2s ((struct sockaddr *) &sa, sizeof (sa)));
  if ((GNUNET_OK !=
       GNUNET_NETWORK_socket_connect (s, (const struct sockaddr *) &sa,
                                      sizeof (sa))) && (errno != EINPROGRESS))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "connect");
    GNUNET_NETWORK_socket_close (s);
    return;
  }
  ctx = GNUNET_new (struct TcpContext);
  ctx->s = s;
  ctx->data = data;
  GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_SECONDS, s, &tcp_send, ctx);
}


/**
 * Try to send 'data' to the
 * IP 'dst_ipv4' at port 'dport' via UDP.
 *
 * @param dst_ipv4 target IP
 * @param dport target port
 * @param data data to send
 */
static void
try_send_udp (uint32_t dst_ipv4, uint16_t dport, uint16_t data)
{
  struct GNUNET_NETWORK_Handle *s;
  struct sockaddr_in sa;

  s = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
  if (NULL == s)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "socket");
    return;
  }
  memset (&sa, 0, sizeof (sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = sizeof (sa);
#endif
  sa.sin_addr.s_addr = dst_ipv4;
  sa.sin_port = htons (dport);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending UDP packet to `%s'\n",
              GNUNET_a2s ((struct sockaddr *) &sa, sizeof (sa)));
  if (-1 ==
      GNUNET_NETWORK_socket_sendto (s, &data, sizeof (data),
                                    (const struct sockaddr *) &sa, sizeof (sa)))
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "sendto");
  GNUNET_NETWORK_socket_close (s);
}


/**
 * We've received a request to probe a NAT
 * traversal. Do it.
 *
 * @param cls unused
 * @param client handle to client (we always close)
 * @param msg message with details about what to test
 */
static void
test (void *cls, struct GNUNET_SERVER_Client *client,
      const struct GNUNET_MessageHeader *msg)
{
  const struct GNUNET_NAT_TestMessage *tm;
  uint16_t dport;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received test request\n");
  tm = (const struct GNUNET_NAT_TestMessage *) msg;
  dport = ntohs (tm->dport);
  if (0 == dport)
    try_anat (tm->dst_ipv4, ntohs (tm->data), (int) ntohl (tm->is_tcp));
  else if (GNUNET_YES == ntohl (tm->is_tcp))
    try_send_tcp (tm->dst_ipv4, dport, tm->data);
  else
    try_send_udp (tm->dst_ipv4, dport, tm->data);
  GNUNET_SERVER_receive_done (client, GNUNET_NO);
}


/**
 * Task run during shutdown.
 *
 * @param cls unused
 * @param tc scheduler context
 */
static void
shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  GNUNET_SERVER_destroy (server);
  server = NULL;
}


/**
 * 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)
{
  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
    {&test, NULL, GNUNET_MESSAGE_TYPE_NAT_TEST,
     sizeof (struct GNUNET_NAT_TestMessage)},
    {NULL, NULL, 0, 0}
  };
  unsigned int port;
  struct sockaddr_in in4;
  struct sockaddr_in6 in6;

  socklen_t slen[] = {
    sizeof (in4),
    sizeof (in6),
    0
  };
  struct sockaddr *sa[] = {
    (struct sockaddr *) &in4,
    (struct sockaddr *) &in6,
    NULL
  };

  cfg = c;
  if ((args[0] == NULL) || (1 != SSCANF (args[0], "%u", &port)) || (0 == port)
      || (65536 <= port))
  {
    FPRINTF (stderr,
             _
             ("Please pass valid port number as the first argument! (got `%s')\n"),
             args[0]);
    return;
  }
  memset (&in4, 0, sizeof (in4));
  memset (&in6, 0, sizeof (in6));
  in4.sin_family = AF_INET;
  in4.sin_port = htons ((uint16_t) port);
  in6.sin6_family = AF_INET6;
  in6.sin6_port = htons ((uint16_t) port);
#if HAVE_SOCKADDR_IN_SIN_LEN
  in4.sin_len = sizeof (in4);
  in6.sin6_len = sizeof (in6);
#endif
  server =
      GNUNET_SERVER_create (NULL, NULL, (struct sockaddr * const *) sa, slen,
                            GNUNET_TIME_UNIT_SECONDS, GNUNET_YES);
  GNUNET_SERVER_add_handlers (server, handlers);
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
                                NULL);
}


/**
 * Main function of gnunet-nat-server.
 *
 * @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[] = {
    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-server [options] PORT",
                          _("GNUnet NAT traversal test helper daemon"), options,
                          &run, NULL))
  {
    GNUNET_free ((void*) argv);
    return 1;
  }
  GNUNET_free ((void*) argv);
  return 0;
}


/* end of gnunet-nat-server.c */