summaryrefslogtreecommitdiff
path: root/sbin/isakmpd/udp.c
blob: a9cde81c826dc49cbfdd3e5c80276c0b0a59e68a (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
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
/*	$OpenBSD: udp.c,v 1.36 2001/06/29 22:01:27 ho Exp $	*/
/*	$EOM: udp.c,v 1.57 2001/01/26 10:09:57 niklas Exp $	*/

/*
 * Copyright (c) 1998, 1999, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2000 Angelos D. Keromytis.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Ericsson Radio Systems.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifndef linux
#include <sys/sockio.h>
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <err.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "sysdep.h"

#include "conf.h"
#include "if.h"
#include "isakmp.h"
#include "log.h"
#include "message.h"
#include "sysdep.h"
#include "transport.h"
#include "udp.h"
#include "util.h"

#define UDP_SIZE 65536

/* If a system doesn't have SO_REUSEPORT, SO_REUSEADDR will have to do.  */
#ifndef SO_REUSEPORT
#define SO_REUSEPORT SO_REUSEADDR
#endif

/* XXX IPv4 specific.  */
struct udp_transport {
  struct transport transport;
  struct sockaddr *src;
  struct sockaddr *dst;
  int s;
  LIST_ENTRY (udp_transport) link;
};

static struct transport *udp_clone (struct udp_transport *, struct sockaddr *);
static struct transport *udp_create (char *);
static void udp_remove (struct transport *);
static void udp_report (struct transport *);
static int udp_fd_set (struct transport *, fd_set *, int);
static int udp_fd_isset (struct transport *, fd_set *);
static void udp_handle_message (struct transport *);
static struct transport *udp_make (struct sockaddr *);
static int udp_send_message (struct message *);
static void udp_get_dst (struct transport *, struct sockaddr **);
static void udp_get_src (struct transport *, struct sockaddr **);
static char *udp_decode_ids (struct transport *);

static struct transport_vtbl udp_transport_vtbl = {
  { 0 }, "udp",
  udp_create,
  udp_remove,
  udp_report,
  udp_fd_set,
  udp_fd_isset,
  udp_handle_message,
  udp_send_message,
  udp_get_dst,
  udp_get_src,
  udp_decode_ids
};

/* A list of UDP transports we listen for messages on.  */
static LIST_HEAD (udp_listen_list, udp_transport) udp_listen_list;

char *udp_default_port = 0;
char *udp_bind_port = 0;
static struct transport *default_transport, *default_transport6;

/* Find an UDP transport listening on ADDR:PORT.  */
static struct udp_transport *
udp_listen_lookup (struct sockaddr *addr)
{
  struct udp_transport *u;

  for (u = LIST_FIRST (&udp_listen_list); u; u = LIST_NEXT (u, link))
    /* XXX enough ? */
    if (u->src->sa_len == addr->sa_len &&
	memcmp (u->src, addr, addr->sa_len) == 0)
      return u;
  return 0;
}

/* Create a UDP transport structure bound to LADDR just for listening.  */
static struct transport *
udp_make (struct sockaddr *laddr)
{
  struct udp_transport *t = 0;
  int s, on;

  t = calloc (1, sizeof *t);
  if (!t)
    {
      log_print ("udp_make: malloc (%d) failed", sizeof *t);
      return 0;
    }

  s = socket (laddr->sa_family, SOCK_DGRAM, IPPROTO_UDP);
  if (s == -1)
    {
      log_error ("udp_make: socket (%d, %d, %d)", laddr->sa_family, SOCK_DGRAM,
		 IPPROTO_UDP);
      goto err;
    }

  /* Make sure we don't get our traffic encrypted.  */
  if (sysdep_cleartext (s, laddr->sa_family) == -1)
    goto err;

  /*
   * In order to have several bound specific address-port combinations
   * with the same port SO_REUSEADDR is needed.
   * If this is a wildcard socket and we are not listening there, but only
   * sending from it make sure it is entirely reuseable with SO_REUSEPORT.
   */
  on = 1;
  if (setsockopt (s, SOL_SOCKET,
#if 0
		  (laddr->sin_addr.s_addr == INADDR_ANY
		   && conf_get_str ("General", "Listen-on"))
		  ? SO_REUSEPORT : SO_REUSEADDR,
#else
		  SO_REUSEADDR,
#endif
		  (void *)&on, sizeof on) == -1)
    {
      log_error ("udp_make: setsockopt (%d, %d, %d, %p, %d)", s, SOL_SOCKET,
#if 0
		 (laddr->sin_addr.s_addr == INADDR_ANY
		  && conf_get_str ("General", "Listen-on"))
		 ? SO_REUSEPORT : SO_REUSEADDR,
#else
		 SO_REUSEADDR,
#endif
		 &on, sizeof on);
      goto err;
    }

  t->transport.vtbl = &udp_transport_vtbl;
  t->src = laddr;
  if (bind (s, t->src, t->src->sa_len))
    {
      char *tstr;
      if (sockaddr2text (t->src, &tstr, 0))
	  log_error ("udp_make: bind (%d, %p, %d)", s, &t->src, sizeof t->src);
      else
	{
	  log_error ("udp_make: bind (%d, %s, %d)", s, tstr, sizeof t->src);
	  free (tstr);
	}
      goto err;
    }

  t->s = s;
  transport_add (&t->transport);
  transport_reference (&t->transport);
  t->transport.flags |= TRANSPORT_LISTEN;
  return &t->transport;

err:
  if (s != -1)
    close (s);
  if (t)
    udp_remove (&t->transport);
  return 0;
}

/* Clone a listen transport U, record a destination RADDR for outbound use.  */
static struct transport *
udp_clone (struct udp_transport *u, struct sockaddr *raddr)
{
  struct transport *t;
  struct udp_transport *u2;

  t = malloc (sizeof *u);
  if (!t)
    {
      log_error ("udp_clone: malloc (%d) failed", sizeof *u);
      return 0;
    }
  u2 = (struct udp_transport *)t;

  memcpy (u2, u, sizeof *u);

  u2->src = malloc (u->src->sa_len);
  if (!u2->src)
    {
      free (t);
      return 0;
    }
  memcpy (u2->src, u->src, u->src->sa_len);

  u2->dst = malloc (raddr->sa_len);
  if (!u2->dst)
    {
      free (u2->src);
      free (t);
      return 0;
    }
  memcpy (u2->dst, raddr, raddr->sa_len);

  t->flags &= ~TRANSPORT_LISTEN;

  transport_add (t);

  return t;
}

/*
 * Initialize an object of the UDP transport class.  Fill in the local
 * IP address and port information and create a server socket bound to
 * that specific port.  Add the polymorphic transport structure to the
 * system-wide pools of known ISAKMP transports.
 */
static struct transport *
udp_bind (struct sockaddr *addr)
{
  struct sockaddr *src = malloc (addr->sa_len);

  if (!src)
    return 0;

  memcpy (src, addr, addr->sa_len);
  return udp_make (src);
}

/*
 * When looking at a specific network interface address, if it's an INET one,
 * create an UDP server socket bound to it.
 */
static void
udp_bind_if (struct ifreq *ifrp, void *arg)
{
  char *port = (char *)arg;
  struct sockaddr *if_addr = &ifrp->ifr_addr;
  struct conf_list *listen_on;
  struct conf_list_node *address;
  struct sockaddr *addr;
  struct transport *t;
  struct ifreq flags_ifr;
  char *addr_str;
  int s, error;

  /*
   * Well, UDP is an internet protocol after all so drop other ifreqs.
   */
#ifdef USE_OLD_SOCKADDR
  if (if_addr->sa_family != AF_INET && if_addr->sa_family != AF_INET6)
    return;
#else
  if ((if_addr->sa_family != AF_INET ||
       if_addr->sa_len != sizeof (struct sockaddr_in)) &&
      (if_addr->sa_family != AF_INET6 ||
       if_addr->sa_len != sizeof (struct sockaddr_in6)))
    return;
#endif

  /*
   * These special addresses are not useable as they have special meaning
   * in the IP stack.
   */
  if (if_addr->sa_family == AF_INET && 
      (((struct sockaddr_in *)&ifrp->ifr_addr)->sin_addr.s_addr == INADDR_ANY
       || (((struct sockaddr_in *)&ifrp->ifr_addr)->sin_addr.s_addr
	   == INADDR_NONE)) )
    return;

  /* Don't bother with interfaces that are down.  */
  s = socket (if_addr->sa_family, SOCK_DGRAM, 0);
  if (s == -1)
    {
      log_error ("udp_bind_if: socket (%d, SOCK_DGRAM, 0) failed",
		 if_addr->sa_family);
      return;
    }
  strncpy (flags_ifr.ifr_name, ifrp->ifr_name, sizeof flags_ifr.ifr_name - 1);
  if (ioctl (s, SIOCGIFFLAGS, (caddr_t)&flags_ifr) == -1)
    {
      log_error ("udp_bind_if: ioctl (%d, SIOCGIFFLAGS, ...) failed", s);
      return;
    }
  close (s);
  if (!(flags_ifr.ifr_flags & IFF_UP))
    return;

  /* Set port */
  switch (if_addr->sa_family)
    {
    case AF_INET:
      ((struct sockaddr_in *)if_addr)->sin_port = 
	htons((in_port_t)strtol (port, NULL, 10));
      break;
    case AF_INET6:
      ((struct sockaddr_in6 *)if_addr)->sin6_port = 
	htons((in_port_t)strtol (port, NULL, 10));
      break;
    default:
      log_print ("udp_bind_if: unsupported protocol family %d",
		 if_addr->sa_family);
      break;
    }

  /*
   * If we are explicit about what addresses we can listen to, be sure
   * to respect that option.
   * This is quite wasteful redoing the list-run for every interface,
   * but who cares?  This is not an operation that needs to be fast.
   */
  listen_on = conf_get_list ("General", "Listen-on");
  if (listen_on)
    {
      for (address = TAILQ_FIRST (&listen_on->fields); address;
	   address = TAILQ_NEXT (address, link))
	{
	  if (text2sockaddr (address->field, port, &addr))
	    {
	      log_print ("udp_bind_if: invalid address %s in \"Listen-on\"",
			 address->field);
	      continue;
	    }

	  /* If found, take the easy way out. */
	  if (memcmp (addr, if_addr, addr->sa_len) == 0)
	    {
	      free (addr);
	      break;
	    }
	  free (addr);
	}
      conf_free_list (listen_on);

      /*
       * If address is zero then we did not find the address among the ones
       * we should listen to.
       * XXX We do not discover if we do not find our listen addresses...
       * Maybe this should be the other way round.
       */
      if (!address)
	return;
    }

  t = udp_bind (if_addr);
  if (!t)
    {
      error = sockaddr2text (if_addr, &addr_str, 0);
      log_print ("udp_bind_if: failed to create a socket on %s:%s",
		 error ? "unknown" : addr_str, port);
      if (!error)
	free (addr_str);
      return;
    }
  LIST_INSERT_HEAD (&udp_listen_list, (struct udp_transport *)t, link);
}

/*
 * NAME is a section name found in the config database.  Setup and return
 * a transport useable to talk to the peer specified by that name.
 */
static struct transport *
udp_create (char *name)
{
  struct udp_transport *u;
  struct transport *rv;
  struct sockaddr *dst, *addr;
  char *addr_str, *port_str;

  port_str = conf_get_str (name, "Port");
  if (!port_str)
    port_str = udp_default_port;
  if (!port_str)
    port_str = "500";

  addr_str = conf_get_str (name, "Address");
  if (!addr_str)
    {
      log_print ("udp_create: no address configured for \"%s\"", name);
      return 0;
    }
  if (text2sockaddr (addr_str, port_str, &dst))
    {
      log_print ("udp_create: address \"%s\" not understood", addr_str);
      return 0;
    }

  addr_str = conf_get_str (name, "Local-address");
  if (!addr_str)
    addr_str = conf_get_str ("General", "Listen-on");
  if (!addr_str)
    {
      if ((dst->sa_family == AF_INET && !default_transport) ||
	  (dst->sa_family == AF_INET6 && !default_transport6))
	{
	  log_print ("udp_create: no default transport");
	  rv = 0;
	  goto ret;
	}
      else
	{
	  /* XXX Ugly!  */
	  rv = udp_clone ((struct udp_transport *)(dst->sa_family == AF_INET
						   ? default_transport
						   : default_transport6), dst);
	  goto ret;
	}
    }

  log_print ("udp_create: addr_str = [%s]", addr_str);
  if (text2sockaddr (addr_str, port_str, &addr))
    {
      log_print ("udp_create: address \"%s\" not understood", addr_str);
      rv = 0;
      goto ret;
    }
  u = udp_listen_lookup (addr);
  free (addr);
  if (!u)
    {
      log_print ("udp_create: %s:%s must exist as a listener too", addr_str,
		 udp_default_port);
      rv = 0;
      goto ret;
    } 
  rv = udp_clone (u, dst);

 ret:
  free (dst);
  return rv;
}

void
udp_remove (struct transport *t)
{
  struct udp_transport *u = (struct udp_transport *)t;

  if (u->src)
    free (u->src);
  if (u->dst)
    free (u->dst);
  free (t);
}

/* Report transport-method specifics of the T transport.  */
void
udp_report (struct transport *t)
{
  struct udp_transport *u = (struct udp_transport *)t;
  char *src, *dst;

  if (sockaddr2text (u->src, &src, 0) || sockaddr2text (u->dst, &dst, 0))
    goto ret;

  LOG_DBG ((LOG_REPORT, 0, "udp_report: fd %d src %s dst %s", u->s, src, dst));

 ret:
  if (dst)
    free (dst);
  if (src)
    free (src);
}

/*
 * Find out the magic numbers for the UDP protocol as well as the UDP port
 * to use.  Setup an UDP server for each address of this machine, and one
 * for the generic case when we are the initiator.
 */
void
udp_init ()
{
  struct sockaddr_storage dflt_stor;
  struct sockaddr_in *dflt = (struct sockaddr_in *)&dflt_stor;
  char *port;

  /* Initialize the protocol and port numbers.  */
  port = udp_default_port ? udp_default_port : "500";

  LIST_INIT (&udp_listen_list);

  /* Bind the ISAKMP UDP port on all network interfaces we have.  */
  /* XXX need to check errors */
  if_map (udp_bind_if, port);

  if (conf_get_str("General", "Listen-on"))
    return;

  /*
   * If we don't bind to specific addresses via the Listen-on configuration
   * option, bind to INADDR_ANY in case of new addresses popping up.
   * XXX We should use packets coming in on this socket as a signal
   * to reprobe for new interfaces.
   */
  memset (&dflt_stor, 0, sizeof dflt_stor);
  dflt->sin_family = AF_INET;
  ((struct sockaddr_in *)dflt)->sin_len = sizeof (struct sockaddr_in);
  ((struct sockaddr_in *)dflt)->sin_port = 
    htons ((in_port_t)strtol (port, NULL, 10));

  default_transport = udp_bind ((struct sockaddr *)&dflt_stor);
  if (!default_transport)
    log_error ("udp_init: could not allocate default IPv4 ISAKMP UDP port");
  else if (conf_get_str ("General", "Listen-on"))
    default_transport->flags &= ~TRANSPORT_LISTEN;

  memset (&dflt_stor, 0, sizeof dflt_stor);
  dflt->sin_family = AF_INET6;
  ((struct sockaddr_in6 *)dflt)->sin6_len = sizeof (struct sockaddr_in6);
  ((struct sockaddr_in6 *)dflt)->sin6_port = 
    htons ((in_port_t)strtol (port, NULL, 10));

  default_transport6 = udp_bind ((struct sockaddr *)&dflt_stor);
  if (!default_transport6)
    log_error ("udp_init: could not allocate default IPv6 ISAKMP UDP port");
  else if (conf_get_str ("General", "Listen-on"))
    default_transport6->flags &= ~TRANSPORT_LISTEN;

  transport_method_add (&udp_transport_vtbl);
}

/*
 * Set transport T's socket in FDS, return a value useable by select(2)
 * as the number of file descriptors to check.
 */
static int
udp_fd_set (struct transport *t, fd_set *fds, int bit)
{
  struct udp_transport *u = (struct udp_transport *)t;

  if (bit)
    FD_SET (u->s, fds);
  else
    FD_CLR (u->s, fds);

  return u->s + 1;
}

/* Check if transport T's socket is set in FDS.  */
static int
udp_fd_isset (struct transport *t, fd_set *fds)
{
  struct udp_transport *u = (struct udp_transport *)t;

  return FD_ISSET (u->s, fds);
}

/*
 * A message has arrived on transport T's socket.  If T is single-ended,
 * clone it into a double-ended transport which we will use from now on.
 * Package the message as we want it and continue processing in the message
 * module.
 */
static void
udp_handle_message (struct transport *t)
{
  struct udp_transport *u = (struct udp_transport *)t;
  u_int8_t buf[UDP_SIZE];
  struct sockaddr_storage from;
  int len = sizeof from;
  ssize_t n;
  struct message *msg;

  n = recvfrom (u->s, buf, UDP_SIZE, 0, (struct sockaddr *)&from, &len);
  if (n == -1)
    {
      log_error ("recvfrom (%d, %p, %d, %d, %p, %p)", u->s, buf, UDP_SIZE, 0,
		 &from, &len);
      return;
    }

  /*
   * Make a specialized UDP transport structure out of the incoming
   * transport and the address information we got from recvfrom(2).
   */
  t = udp_clone (u, (struct sockaddr *)&from);
  if (!t)
    /* XXX Should we do more here?  */
    return;

  msg = message_alloc (t, buf, n);
  if (!msg)
    /* XXX Log?  */
    return;
  message_recv (msg);
}

/* Physically send the message MSG over its associated transport.  */
static int
udp_send_message (struct message *msg)
{
  struct udp_transport *u = (struct udp_transport *)msg->transport;
  ssize_t n;
  struct msghdr m;

  /*
   * Sending on connected sockets requires that no destination address is
   * given, or else EISCONN will occur.
   */
  m.msg_name = (caddr_t)u->dst;
  m.msg_namelen = u->dst->sa_len;
  m.msg_iov = msg->iov;
  m.msg_iovlen = msg->iovlen;
  m.msg_control = 0;
  m.msg_controllen = 0;
  m.msg_flags = 0;
  n = sendmsg (u->s, &m, 0);
  if (n == -1)
    {
      log_error ("sendmsg (%d, %p, %d)", u->s, &m, 0);
      return -1;
    }
  return 0;
}

/*
 * Get transport T's peer address and stuff it into the sockaddr pointed
 * to by DST.
 */
static void
udp_get_dst (struct transport *t, struct sockaddr **dst)
{
  *dst = ((struct udp_transport *)t)->dst;
}

/*
 * Get transport T's local address and stuff it into the sockaddr pointed
 * to by SRC.  Put its length into SRC_LEN.
 */
static void
udp_get_src (struct transport *t, struct sockaddr **src)
{
  *src = ((struct udp_transport *)t)->src;
}

static char *
udp_decode_ids (struct transport *t)
{
  static char result[1024];
  char idsrc[256], iddst[256];

#ifdef HAVE_GETNAMEINFO
  if (getnameinfo ((struct sockaddr *)&((struct udp_transport *)t)->src,
		   sizeof ((struct udp_transport *)t)->src,
		   idsrc, sizeof idsrc, NULL, 0, NI_NUMERICHOST) != 0)
    {
      log_print ("udp_decode_ids: getnameinfo () failed");
      strcpy (idsrc, "<error>");
    }

  if (getnameinfo ((struct sockaddr *)&((struct udp_transport *)t)->dst,
		   sizeof ((struct udp_transport *)t)->dst,
		   iddst, sizeof iddst, NULL, 0, NI_NUMERICHOST) != 0)
    {
      log_error ("udp_decode_ids: getnameinfo () failed");
      strcpy (iddst, "<error>");
    }
#else
  strcpy (idsrc, inet_ntoa (((struct udp_transport *)t)->src.sin_addr));
  strcpy (iddst, inet_ntoa (((struct udp_transport *)t)->dst.sin_addr));
#endif /* HAVE_GETNAMEINFO */

  sprintf (result, "src: %s dst: %s", idsrc, iddst);

  return result;
}
/*
 * Take a string containing an ext representation of port and return a
 * binary port number in host byte order.  Return zero if anything goes wrong.
 */
in_port_t
udp_decode_port (char *port_str)
{
  char *port_str_end;
  long port_long;
  struct servent *service;

  port_long = ntohl (strtol (port_str, &port_str_end, 0));
  if (port_str == port_str_end)
    {
      service = getservbyname (port_str, "udp");
      if (!service)
	{
	  log_print ("udp_decode_port: service \"%s\" unknown", port_str);
	  return 0;
	}
      return ntohs (service->s_port);
    }
  else if (port_long < 1 || port_long > 65535)
    {
      log_print ("udp_decode_port: port %ld out of range", port_long);
      return 0;
    }

  return port_long;
}