aboutsummaryrefslogtreecommitdiff
path: root/src/transport/plugin_transport_udp.c
blob: 739716b17d7b6724b2e09bff195caa5a7b8129d7 (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
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
/*
     This file is part of GNUnet
     (C) 2010 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 2, 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., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file transport/plugin_transport_udp.c
 * @brief Implementation of the UDP transport service
 * @author Christian Grothoff
 * @author Nathan Evans
 */

#include "platform.h"
#include "gnunet_hello_lib.h"
#include "gnunet_connection_lib.h"
#include "gnunet_os_lib.h"
#include "gnunet_peerinfo_service.h"
#include "gnunet_protocols.h"
#include "gnunet_resolver_service.h"
#include "gnunet_server_lib.h"
#include "gnunet_service_lib.h"
#include "gnunet_signatures.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "plugin_transport.h"
#include "transport.h"

#define DEBUG_UDP GNUNET_NO

/**
 * Transport cost to peer, always 1 for UDP (direct connection)
 */
#define UDP_DIRECT_DISTANCE 1

/**
 * How long until we give up on transmitting the welcome message?
 */
#define HOSTNAME_RESOLVE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)


/**
 * Message-Packet header.
 */
struct UDPMessage
{
  /**
   * size of the message, in bytes, including this header.
   */
  struct GNUNET_MessageHeader header;

  /**
   * What is the identity of the sender (GNUNET_hash of public key)
   */
  struct GNUNET_PeerIdentity sender;

};


struct PrettyPrinterContext
{
  GNUNET_TRANSPORT_AddressStringCallback asc;
  void *asc_cls;
  uint16_t port;
};

/**
 * Encapsulation of all of the state of the plugin.
 */
struct Plugin
{
  /**
   * Our environment.
   */
  struct GNUNET_TRANSPORT_PluginEnvironment *env;

  /**
   * Handle for the statistics service.
   */
  struct GNUNET_STATISTICS_Handle *statistics;

  /**
   * Handle to the network service.
   */
  struct GNUNET_SERVICE_Context *service;

  /**
   * Handle for request of hostname resolution, non-NULL if pending.
   */
  struct GNUNET_RESOLVER_RequestHandle *hostname_dns;

  /**
   * FD Read set
   */
  struct GNUNET_NETWORK_FDSet *rs;

  /**
   * ID of task used to update our addresses when one expires.
   */
  GNUNET_SCHEDULER_TaskIdentifier address_update_task;

  /**
   * ID of select task
   */
  GNUNET_SCHEDULER_TaskIdentifier select_task;

  /**
   * Port that we are actually listening on.
   */
  uint16_t open_port;

  /**
   * Port that the user said we would have visible to the
   * rest of the world.
   */
  uint16_t adv_port;

};

/* *********** globals ************* */

/**
 * the socket that we transmit all data with
 */
static struct GNUNET_NETWORK_Handle *udp_sock;

/**
 * Disconnect from a remote node.
 *
 * @param cls closure ('struct Plugin'), unused
 * @param target peer do disconnect
 * @return GNUNET_OK on success, GNUNET_SYSERR if the operation failed
 */
void
udp_disconnect (void *cls, const struct GNUNET_PeerIdentity *target)
{
  /* nothing to do, UDP is stateless */
}

/**
 * Shutdown the server process (stop receiving inbound traffic). Maybe
 * restarted later!
 */
static int
udp_transport_server_stop (void *cls)
{
  struct Plugin *plugin = cls;
  int ret;

  GNUNET_assert (udp_sock != NULL);
  if (plugin->select_task != GNUNET_SCHEDULER_NO_TASK)
    {
      GNUNET_SCHEDULER_cancel (plugin->env->sched, plugin->select_task);
      plugin->select_task = GNUNET_SCHEDULER_NO_TASK;
    }

  ret = GNUNET_NETWORK_socket_close (udp_sock);
  if (ret != GNUNET_SYSERR)
    udp_sock = NULL;
  return ret;
}

/**
 * Function that can be used by the transport service to transmit
 * a message using the plugin.
 *
 * @param cls closure
 * @param target who should receive this message (ignored by UDP)
 * @param msgbuf one or more GNUNET_MessageHeader(s) strung together
 * @param msgbuf_size the size of the msgbuf to send
 * @param priority how important is the message (ignored by UDP)
 * @param timeout when should we time out (give up) if we can not transmit?
 * @param addr the addr to send the message to, needs to be a sockaddr for us
 * @param addrlen the len of addr
 * @param force_address not used, we had better have an address to send to
 *        because we are stateless!!
 * @param cont continuation to call once the message has
 *        been transmitted (or if the transport is ready
 *        for the next transmission call; or if the
 *        peer disconnected...)
 * @param cont_cls closure for cont
 *
 * @return the number of bytes written, -1 on error (in this case, cont is not called)
 */
static ssize_t
udp_plugin_send (void *cls,
                 const struct GNUNET_PeerIdentity *target,
                 const char *msgbuf,
                 size_t msgbuf_size,
                 unsigned int priority,
                 struct GNUNET_TIME_Relative timeout,
                 const void *addr,
                 size_t addrlen,
                 int force_address,
                 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls)
{
  struct Plugin *plugin = cls;
  struct UDPMessage *message;
  int ssize;
  ssize_t sent;

  GNUNET_assert(udp_sock != NULL);
  if ( (addr == NULL) || (addrlen == 0) )
    {
#if DEBUG_UDP
  GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                   ("udp_plugin_send called without address, returning!\n"));
#endif
      return -1; /* Can never send if we don't have an address!! */
    }

  /* Build the message to be sent */
  message = GNUNET_malloc (sizeof (struct UDPMessage) + msgbuf_size);
  ssize = sizeof (struct UDPMessage) + msgbuf_size;

#if DEBUG_UDP
  GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                   ("In udp_send, ssize is %d, sending message to %s\n"), ssize, GNUNET_a2s((const struct sockaddr *)addr, addrlen));
#endif
  message->header.size = htons (ssize);
  message->header.type = htons (0);
  memcpy (&message->sender, plugin->env->my_identity,
          sizeof (struct GNUNET_PeerIdentity));
  memcpy (&message[1], msgbuf, msgbuf_size);
  sent =
    GNUNET_NETWORK_socket_sendto (udp_sock, message, ssize,
                                  addr,
                                  addrlen);
  if ( (cont != NULL) &&
       (sent != -1) )
    cont (cont_cls, target, GNUNET_OK);
  GNUNET_free (message);
  return sent;
}


/**
 * Add the IP of our network interface to the list of
 * our external IP addresses.
 */
static int
process_interfaces (void *cls,
                    const char *name,
                    int isDefault,
                    const struct sockaddr *addr, socklen_t addrlen)
{
  struct Plugin *plugin = cls;
  int af;
  struct sockaddr_in *v4;
  struct sockaddr_in6 *v6;

  af = addr->sa_family;
  if (af == AF_INET)
    {
      v4 = (struct sockaddr_in *) addr;
      v4->sin_port = htons (plugin->adv_port);
    }
  else
    {
      GNUNET_assert (af == AF_INET6);
      v6 = (struct sockaddr_in6 *) addr;
      v6->sin6_port = htons (plugin->adv_port);
    }
  GNUNET_log_from (GNUNET_ERROR_TYPE_INFO |
                   GNUNET_ERROR_TYPE_BULK,
                   "udp", _("Found address `%s' (%s)\n"),
                   GNUNET_a2s (addr, addrlen), name);
  plugin->env->notify_address (plugin->env->cls,
                               "udp",
                               addr, addrlen, GNUNET_TIME_UNIT_FOREVER_REL);

  return GNUNET_OK;
}


/**
 * Function called by the resolver for each address obtained from DNS
 * for our own hostname.  Add the addresses to the list of our
 * external IP addresses.
 *
 * @param cls closure
 * @param addr one of the addresses of the host, NULL for the last address
 * @param addrlen length of the address
 */
static void
process_hostname_ips (void *cls,
                      const struct sockaddr *addr, socklen_t addrlen)
{
  struct Plugin *plugin = cls;

  if (addr == NULL)
    {
      plugin->hostname_dns = NULL;
      return;
    }
  process_interfaces (plugin, "<hostname>", GNUNET_YES, addr, addrlen);
}


/*
 * @param cls the plugin handle
 * @param tc the scheduling context (for rescheduling this function again)
 *
 * We have been notified that our writeset has something to read.  Presumably
 * select has been called already, so we can go ahead and start reading from
 * the socket immediately.  Then we check if there is more to be read by
 * calling select ourselves while there is stuff on the wire.  Then reschedule
 * this function to be called again once more is available.
 *
 */
static void
udp_plugin_select (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct Plugin *plugin = cls;
  char *buf;
  struct UDPMessage *msg;
  struct GNUNET_PeerIdentity *sender;
  unsigned int buflen;
  socklen_t fromlen;
  struct sockaddr_storage addr;
  ssize_t ret;
  int offset;
  int count;
  int tsize;
  char *msgbuf;
  const struct GNUNET_MessageHeader *currhdr;

#if DEBUG_UDP
      GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                       ("entered select...\n"));
#endif

      buflen = GNUNET_NETWORK_socket_recvfrom_amount (udp_sock);

#if DEBUG_UDP
      GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                       ("we expect to read %u bytes\n"), buflen);
#endif

    if (buflen == GNUNET_NO)
      return;

    buf = GNUNET_malloc (buflen);
    fromlen = sizeof (addr);

    memset (&addr, 0, fromlen);
    ret =
      GNUNET_NETWORK_socket_recvfrom (udp_sock, buf, buflen,
                                      (struct sockaddr *) &addr, &fromlen);

#if DEBUG_UDP
    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                     ("socket_recv returned %u, src_addr_len is %u\n"), ret,
                     fromlen);
#endif

    if (ret <= 0)
      {
        GNUNET_free (buf);
        return;
      }
    msg = (struct UDPMessage *) buf;

#if DEBUG_UDP
    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                     ("header reports message size of %d\n"),
                     ntohs (msg->header.size));

    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                     ("header reports message type of %d\n"),
                     ntohs (msg->header.type));
#endif
    if (ntohs (msg->header.size) < sizeof (struct UDPMessage))
      {
        GNUNET_free (buf);
        GNUNET_NETWORK_fdset_zero (plugin->rs);
        GNUNET_NETWORK_fdset_set (plugin->rs, udp_sock);
        return;
      }
    msgbuf = (char *)&msg[1];
    sender = GNUNET_malloc (sizeof (struct GNUNET_PeerIdentity));
    memcpy (sender, &msg->sender, sizeof (struct GNUNET_PeerIdentity));

    offset = 0;
    count = 0;
    tsize = ntohs (msg->header.size) - sizeof(struct UDPMessage);
#if DEBUG_UDP
    GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "UDP", _
                     ("offset is %d, tsize is %d (UDPMessage size is %d)\n"),
                     offset, tsize, sizeof(struct UDPMessage));
#endif
    while (offset < tsize)
      {
        currhdr = (struct GNUNET_MessageHeader *)&msgbuf[offset];
#if DEBUG_UDP
    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                     ("processing msg %d: type %d, size %d at offset %d\n"),
                     count, ntohs(currhdr->type), ntohs(currhdr->size), offset);
#endif
        plugin->env->receive (plugin->env->cls,
            sender, currhdr, UDP_DIRECT_DISTANCE, (char *)&addr, fromlen);
        offset += ntohs(currhdr->size);
#if DEBUG_UDP
    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO, "udp", _
                     ("offset now %d, tsize %d\n"),
                     offset, tsize);
#endif
        count++;
      }

    GNUNET_free (sender);
    GNUNET_free (buf);

  plugin->select_task =
    GNUNET_SCHEDULER_add_select (plugin->env->sched,
                                 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
                                 GNUNET_SCHEDULER_NO_TASK,
                                 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
                                 NULL, &udp_plugin_select, plugin);

}

/**
 * Create a UDP socket.  If possible, use IPv6, otherwise
 * try IPv4.
 */
static struct GNUNET_NETWORK_Handle *
udp_transport_server_start (void *cls)
{
  struct Plugin *plugin = cls;
  struct GNUNET_NETWORK_Handle *desc;
  struct sockaddr_in serverAddrv4;
  struct sockaddr_in6 serverAddrv6;
  struct sockaddr *serverAddr;
  socklen_t addrlen;

  desc = NULL;
  if (GNUNET_YES !=
      GNUNET_CONFIGURATION_get_value_yesno (plugin->env->cfg, "GNUNETD",
                                            "DISABLE-IPV6"))
    {
      desc = GNUNET_NETWORK_socket_create (PF_INET6, SOCK_DGRAM, 17);
      if (desc != NULL)
        {
          memset (&serverAddrv6, 0, sizeof (serverAddrv6));
#if HAVE_SOCKADDR_IN_SIN_LEN
          serverAddrv6.sin6_len = sizeof (serverAddrv6);
#endif
          serverAddrv6.sin6_family = AF_INET6;
          serverAddrv6.sin6_addr = in6addr_any;
          serverAddrv6.sin6_port = htons (plugin->open_port);
          addrlen = sizeof (serverAddrv6);
          serverAddr = (struct sockaddr *) &serverAddrv6;
        }
    }
  if (NULL == desc)
    {
      desc = GNUNET_NETWORK_socket_create (PF_INET, SOCK_DGRAM, 17);
      if (NULL == desc)
        {
          GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "udp", "socket");
          return NULL;
        }
      else
        {
          memset (&serverAddrv4, 0, sizeof (serverAddrv4));
#if HAVE_SOCKADDR_IN_SIN_LEN
          serverAddrv4.sin_len = sizeof (serverAddrv4);
#endif
          serverAddrv4.sin_family = AF_INET;
          serverAddrv4.sin_addr.s_addr = INADDR_ANY;
          serverAddrv4.sin_port = htons (plugin->open_port);
          addrlen = sizeof (serverAddrv4);
          serverAddr = (struct sockaddr *) &serverAddrv4;
        }
    }

  if (desc != NULL)
    {
      GNUNET_assert (GNUNET_NETWORK_socket_bind (desc, serverAddr, addrlen) ==
                     GNUNET_OK);
    }

  plugin->rs = GNUNET_NETWORK_fdset_create ();

  GNUNET_NETWORK_fdset_zero (plugin->rs);
  GNUNET_NETWORK_fdset_set (plugin->rs, desc);

  plugin->select_task =
    GNUNET_SCHEDULER_add_select (plugin->env->sched,
                                 GNUNET_SCHEDULER_PRIORITY_DEFAULT,
                                 GNUNET_SCHEDULER_NO_TASK,
                                 GNUNET_TIME_UNIT_FOREVER_REL, plugin->rs,
                                 NULL, &udp_plugin_select, plugin);

  return desc;
}


/**
 * Check if the given port is plausible (must be either
 * our listen port or our advertised port).  If it is
 * neither, we return one of these two ports at random.
 *
 * @return either in_port or a more plausible port
 */
static uint16_t
check_port (struct Plugin *plugin, uint16_t in_port)
{
  if ((in_port == plugin->adv_port) || (in_port == plugin->open_port))
    return in_port;
  return (GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
                                    2) == 0)
    ? plugin->open_port : plugin->adv_port;
}


/**
 * Another peer has suggested an address for this peer and transport
 * plugin.  Check that this could be a valid address.  This function
 * is not expected to 'validate' the address in the sense of trying to
 * connect to it but simply to see if the binary format is technically
 * legal for establishing a connection.
 *
 * @param cls handle to Plugin
 * @param addr address to check
 * @param addrlen length of addr
 * @return GNUNET_OK if this is a plausible address for this peer
 *         and transport, GNUNET_SYSERR if not
 *
 * TODO: perhaps make everything work with sockaddr_storage, it may
 *       be a cleaner way to handle addresses in UDP
 */
static int
udp_check_address (void *cls, void *addr, size_t addrlen)
{
  struct Plugin *plugin = cls;
  char buf[sizeof (struct sockaddr_in6)];

  struct sockaddr_in *v4;
  struct sockaddr_in6 *v6;

  if ((addrlen != sizeof (struct sockaddr_in)) &&
      (addrlen != sizeof (struct sockaddr_in6)))
    {
      GNUNET_break_op (0);
      return GNUNET_SYSERR;
    }
  memcpy (buf, addr, sizeof (struct sockaddr_in6));
  if (addrlen == sizeof (struct sockaddr_in))
    {
      v4 = (struct sockaddr_in *) buf;
      v4->sin_port = htons (check_port (plugin, ntohs (v4->sin_port)));
    }
  else
    {
      v6 = (struct sockaddr_in6 *) buf;
      v6->sin6_port = htons (check_port (plugin, ntohs (v6->sin6_port)));
    }
#if DEBUG_UDP
  GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
                   "tcp",
                   "Informing transport service about my address `%s'.\n",
                   GNUNET_a2s (addr, addrlen));
#endif
  return GNUNET_OK;
  return GNUNET_OK;
}


/**
 * Append our port and forward the result.
 */
static void
append_port (void *cls, const char *hostname)
{
  struct PrettyPrinterContext *ppc = cls;
  char *ret;

  if (hostname == NULL)
    {
      ppc->asc (ppc->asc_cls, NULL);
      GNUNET_free (ppc);
      return;
    }
  GNUNET_asprintf (&ret, "%s:%d", hostname, ppc->port);
  ppc->asc (ppc->asc_cls, ret);
  GNUNET_free (ret);
}


/**
 * Convert the transports address to a nice, human-readable
 * format.
 *
 * @param cls closure
 * @param type name of the transport that generated the address
 * @param addr one of the addresses of the host, NULL for the last address
 *        the specific address format depends on the transport
 * @param addrlen length of the address
 * @param numeric should (IP) addresses be displayed in numeric form?
 * @param timeout after how long should we give up?
 * @param asc function to call on each string
 * @param asc_cls closure for asc
 */
static void
udp_plugin_address_pretty_printer (void *cls,
                                   const char *type,
                                   const void *addr,
                                   size_t addrlen,
                                   int numeric,
                                   struct GNUNET_TIME_Relative timeout,
                                   GNUNET_TRANSPORT_AddressStringCallback asc,
                                   void *asc_cls)
{
  struct Plugin *plugin = cls;
  const struct sockaddr_in *v4;
  const struct sockaddr_in6 *v6;
  struct PrettyPrinterContext *ppc;

  if ((addrlen != sizeof (struct sockaddr_in)) &&
      (addrlen != sizeof (struct sockaddr_in6)))
    {
      /* invalid address */
      GNUNET_break_op (0);
      asc (asc_cls, NULL);
      return;
    }
  ppc = GNUNET_malloc (sizeof (struct PrettyPrinterContext));
  ppc->asc = asc;
  ppc->asc_cls = asc_cls;
  if (addrlen == sizeof (struct sockaddr_in))
    {
      v4 = (const struct sockaddr_in *) addr;
      ppc->port = ntohs (v4->sin_port);
    }
  else
    {
      v6 = (const struct sockaddr_in6 *) addr;
      ppc->port = ntohs (v6->sin6_port);

    }
  GNUNET_RESOLVER_hostname_get (plugin->env->sched,
                                plugin->env->cfg,
                                addr,
                                addrlen,
                                !numeric, timeout, &append_port, ppc);
}


/**
 * The exported method. Makes the core api available via a global and
 * returns the udp transport API.
 */
void *
libgnunet_plugin_transport_udp_init (void *cls)
{
  struct GNUNET_TRANSPORT_PluginEnvironment *env = cls;
  struct GNUNET_TRANSPORT_PluginFunctions *api;
  struct Plugin *plugin;
  struct GNUNET_SERVICE_Context *service;
  unsigned long long aport;
  unsigned long long bport;
  unsigned long long mtu;

  service = GNUNET_SERVICE_start ("transport-udp", env->sched, env->cfg);
  if (service == NULL)
    {
      GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING, "udp", _
                       ("Failed to start service for `%s' transport plugin.\n"),
                       "udp");
      return NULL;
    }
  aport = 0;
  if ((GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_number (env->cfg,
                                              "transport-udp",
                                              "PORT",
                                              &bport)) ||
      (bport > 65535) ||
      ((GNUNET_OK ==
        GNUNET_CONFIGURATION_get_value_number (env->cfg,
                                               "transport-udp",
                                               "ADVERTISED-PORT",
                                               &aport)) && (aport > 65535)))
    {
      GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
                       "udp",
                       _
                       ("Require valid port number for service `%s' in configuration!\n"),
                       "transport-udp");
      GNUNET_SERVICE_stop (service);
      return NULL;
    }
  if (aport == 0)
    aport = bport;

  mtu = 1240;
  if (mtu < 1200)
    GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
                     "udp",
                     _("MTU %llu for `%s' is probably too low!\n"), mtu,
                     "UDP");

  plugin = GNUNET_malloc (sizeof (struct Plugin));
  plugin->open_port = bport;
  plugin->adv_port = aport;
  plugin->env = env;
  plugin->statistics = NULL;
  api = GNUNET_malloc (sizeof (struct GNUNET_TRANSPORT_PluginFunctions));
  api->cls = plugin;

  api->send = &udp_plugin_send;
  api->disconnect = &udp_disconnect;
  api->address_pretty_printer = &udp_plugin_address_pretty_printer;
  api->check_address = &udp_check_address;

  plugin->service = service;

  /* FIXME: do the two calls below periodically again and
     not just once (since the info we get might change...) */
  GNUNET_OS_network_interfaces_list (&process_interfaces, plugin);
  plugin->hostname_dns = GNUNET_RESOLVER_hostname_resolve (env->sched,
                                                           env->cfg,
                                                           AF_UNSPEC,
                                                           HOSTNAME_RESOLVE_TIMEOUT,
                                                           &process_hostname_ips,
                                                           plugin);

  udp_sock = udp_transport_server_start (plugin);

  GNUNET_assert (udp_sock != NULL);

  return api;
}

void *
libgnunet_plugin_transport_udp_done (void *cls)
{
  struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
  struct Plugin *plugin = api->cls;

  udp_transport_server_stop (plugin);
  if (NULL != plugin->hostname_dns)
    {
      GNUNET_RESOLVER_request_cancel (plugin->hostname_dns);
      plugin->hostname_dns = NULL;
    }
  GNUNET_SERVICE_stop (plugin->service);

  GNUNET_NETWORK_fdset_destroy (plugin->rs);
  GNUNET_free (plugin);
  GNUNET_free (api);
  return NULL;
}

/* end of plugin_transport_udp.c */