aboutsummaryrefslogtreecommitdiff
path: root/inet/getnameinfo.c
blob: e7031d3741cc49e75f04a2b19c6ea264200b11f9 (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
/* Convert socket address to string using Name Service Switch modules.
   Copyright (C) 1997-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* The Inner Net License, Version 2.00

  The author(s) grant permission for redistribution and use in source and
binary forms, with or without modification, of the software and documentation
provided that the following conditions are met:

0. If you receive a version of the software that is specifically labelled
   as not being for redistribution (check the version message and/or README),
   you are not permitted to redistribute that version of the software in any
   way or form.
1. All terms of the all other applicable copyrights and licenses must be
   followed.
2. Redistributions of source code must retain the authors' copyright
   notice(s), this list of conditions, and the following disclaimer.
3. Redistributions in binary form must reproduce the authors' copyright
   notice(s), this list of conditions, and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
4. [The copyright holder has authorized the removal of this clause.]
5. Neither the name(s) of the author(s) nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ITS AUTHORS AND CONTRIBUTORS ``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 AUTHORS OR CONTRIBUTORS 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.

  If these license terms cause you a real problem, contact the author.  */

/* This software is Copyright 1996 by Craig Metz, All Rights Reserved.  */

#include <errno.h>
#include <netdb.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/utsname.h>
#include <libc-lock.h>
#include <scratch_buffer.h>
#include <net-internal.h>

#ifndef min
# define min(x,y) (((x) > (y)) ? (y) : (x))
#endif /* min */

libc_freeres_ptr (static char *domain);

/* Former NI_IDN_ALLOW_UNASSIGNED, NI_IDN_USE_STD3_ASCII_RULES flags,
   now ignored.  */
#define DEPRECATED_NI_IDN 192

static char *
nrl_domainname (void)
{
  static int not_first;

  if (! not_first)
    {
      __libc_lock_define_initialized (static, lock);
      __libc_lock_lock (lock);

      if (! not_first)
	{
	  char *c;
	  struct hostent *h, th;
	  int herror;
	  struct scratch_buffer tmpbuf;

	  scratch_buffer_init (&tmpbuf);
	  not_first = 1;

	  while (__gethostbyname_r ("localhost", &th,
				    tmpbuf.data, tmpbuf.length,
				    &h, &herror))
	    {
	      if (herror == NETDB_INTERNAL && errno == ERANGE)
		{
		  if (!scratch_buffer_grow (&tmpbuf))
		    goto done;
		}
	      else
		break;
	    }

	  if (h && (c = strchr (h->h_name, '.')))
	    domain = __strdup (++c);
	  else
	    {
	      /* The name contains no domain information.  Use the name
		 now to get more information.  */
	      while (__gethostname (tmpbuf.data, tmpbuf.length))
		if (!scratch_buffer_grow (&tmpbuf))
		  goto done;

	      if ((c = strchr (tmpbuf.data, '.')))
		domain = __strdup (++c);
	      else
		{
		  /* We need to preserve the hostname.  */
		  const char *hstname = strdupa (tmpbuf.data);

		  while (__gethostbyname_r (hstname, &th,
					    tmpbuf.data, tmpbuf.length,
					    &h, &herror))
		    {
		      if (herror == NETDB_INTERNAL && errno == ERANGE)
			{
			  if (!scratch_buffer_grow (&tmpbuf))
			    goto done;
			}
		      else
			break;
		    }

		  if (h && (c = strchr(h->h_name, '.')))
		    domain = __strdup (++c);
		  else
		    {
		      struct in_addr in_addr;

		      in_addr.s_addr = htonl (INADDR_LOOPBACK);

		      while (__gethostbyaddr_r ((const char *) &in_addr,
						sizeof (struct in_addr),
						AF_INET, &th,
						tmpbuf.data, tmpbuf.length,
						&h, &herror))
			{
			  if (herror == NETDB_INTERNAL && errno == ERANGE)
			    {
			      if (!scratch_buffer_grow (&tmpbuf))
				goto done;
			    }
			  else
			    break;
			}

		      if (h && (c = strchr (h->h_name, '.')))
			domain = __strdup (++c);
		    }
		}
	    }
	done:
	  scratch_buffer_free (&tmpbuf);
	}

      __libc_lock_unlock (lock);
    }

  return domain;
};

/* Copy a string to a destination buffer with length checking.  Return
   EAI_OVERFLOW if the buffer is not large enough, and 0 on
   success.  */
static int
checked_copy (char *dest, size_t destlen, const char *source)
{
  size_t source_length = strlen (source);
  if (source_length + 1 > destlen)
    return EAI_OVERFLOW;
  memcpy (dest, source, source_length + 1);
  return 0;
}

/* Helper function for CHECKED_SNPRINTF below.  */
static int
check_sprintf_result (int result, size_t destlen)
{
  if (result < 0)
    return EAI_SYSTEM;
  if ((size_t) result >= destlen)
    /* If ret == destlen, there was no room for the terminating NUL
       character.  */
    return EAI_OVERFLOW;
  return 0;
}

/* Format a string in the destination buffer.  Return 0 on success,
   EAI_OVERFLOW in case the buffer is too small, or EAI_SYSTEM on any
   other error.  */
#define CHECKED_SNPRINTF(dest, destlen, format, ...)			\
  check_sprintf_result							\
    (__snprintf (dest, destlen, format, __VA_ARGS__), destlen)

/* Convert host name, AF_INET/AF_INET6 case, name only.  */
static int
gni_host_inet_name (struct scratch_buffer *tmpbuf,
		    const struct sockaddr *sa, socklen_t addrlen,
		    char *host, socklen_t hostlen, int flags)
{
  int herrno;
  struct hostent th;
  struct hostent *h = NULL;
  if (sa->sa_family == AF_INET6)
    {
      const struct sockaddr_in6 *sin6p = (const struct sockaddr_in6 *) sa;
      while (__gethostbyaddr_r (&sin6p->sin6_addr, sizeof(struct in6_addr),
				AF_INET6, &th, tmpbuf->data, tmpbuf->length,
				&h, &herrno))
	if (herrno == NETDB_INTERNAL && errno == ERANGE)
	  {
	    if (!scratch_buffer_grow (tmpbuf))
	      {
		__set_h_errno (herrno);
		return EAI_MEMORY;
	      }
	  }
	else
	  break;
    }
  else
    {
      const struct sockaddr_in *sinp = (const struct sockaddr_in *) sa;
      while (__gethostbyaddr_r (&sinp->sin_addr, sizeof(struct in_addr),
				AF_INET, &th, tmpbuf->data, tmpbuf->length,
				&h, &herrno))
	if (herrno == NETDB_INTERNAL && errno == ERANGE)
	    {
	      if (!scratch_buffer_grow (tmpbuf))
		{
		  __set_h_errno (herrno);
		  return EAI_MEMORY;
		}
	    }
	else
	  break;
    }

  if (h == NULL)
    {
      if (herrno == NETDB_INTERNAL)
	{
	  __set_h_errno (herrno);
	  return EAI_SYSTEM;
	}
      if (herrno == TRY_AGAIN)
	{
	  __set_h_errno (herrno);
	  return EAI_AGAIN;
	}
    }

  if (h)
    {
      char *c;
      if ((flags & NI_NOFQDN)
	  && (c = nrl_domainname ())
	  && (c = strstr (h->h_name, c))
	  && (c != h->h_name) && (*(--c) == '.'))
	/* Terminate the string after the prefix.  */
	*c = '\0';

      /* If requested, convert from the IDN format.  */
      bool do_idn = flags & NI_IDN;
      char *h_name;
      if (do_idn)
	{
	  int rc = __idna_from_dns_encoding (h->h_name, &h_name);
	  if (rc == EAI_IDN_ENCODE)
	    /* Use the punycode name as a fallback.  */
	    do_idn = false;
	  else if (rc != 0)
	    return rc;
	}
      if (!do_idn)
	h_name = h->h_name;

      size_t len = strlen (h_name) + 1;
      if (len > hostlen)
	return EAI_OVERFLOW;
      memcpy (host, h_name, len);

      if (do_idn)
	free (h_name);

      return 0;
    }

  return EAI_NONAME;
}

/* Convert host name, AF_INET/AF_INET6 case, numeric conversion.  */
static int
gni_host_inet_numeric (struct scratch_buffer *tmpbuf,
		       const struct sockaddr *sa, socklen_t addrlen,
		       char *host, socklen_t hostlen, int flags)
{
  if (sa->sa_family == AF_INET6)
    {
      const struct sockaddr_in6 *sin6p = (const struct sockaddr_in6 *) sa;
      if (inet_ntop (AF_INET6, &sin6p->sin6_addr, host, hostlen) == NULL)
	return EAI_OVERFLOW;

      uint32_t scopeid = sin6p->sin6_scope_id;
      if (scopeid != 0)
	{
	  size_t used_hostlen = __strnlen (host, hostlen);
	  /* Location of the scope string in the host buffer.  */
	  char *scope_start = host + used_hostlen;
	  size_t scope_length = hostlen - used_hostlen;

	  if (IN6_IS_ADDR_LINKLOCAL (&sin6p->sin6_addr)
	      || IN6_IS_ADDR_MC_LINKLOCAL (&sin6p->sin6_addr))
	    {
	      char scopebuf[IFNAMSIZ];
	      if (if_indextoname (scopeid, scopebuf) != NULL)
		return CHECKED_SNPRINTF
		  (scope_start, scope_length,
		   "%c%s", SCOPE_DELIMITER, scopebuf);
	    }
	  return CHECKED_SNPRINTF
	    (scope_start, scope_length, "%c%u", SCOPE_DELIMITER, scopeid);
	}
    }
  else
    {
      const struct sockaddr_in *sinp = (const struct sockaddr_in *) sa;
      if (inet_ntop (AF_INET, &sinp->sin_addr, host, hostlen) == NULL)
	return EAI_OVERFLOW;
    }
  return 0;
}

/* Convert AF_INET or AF_INET6 socket address, host part.  */
static int
gni_host_inet (struct scratch_buffer *tmpbuf,
	       const struct sockaddr *sa, socklen_t addrlen,
	       char *host, socklen_t hostlen, int flags)
{
  if (!(flags & NI_NUMERICHOST))
    {
      int result = gni_host_inet_name
	(tmpbuf, sa, addrlen, host, hostlen, flags);
      if (result != EAI_NONAME)
	return result;
    }

  if (flags & NI_NAMEREQD)
    return EAI_NONAME;
  else
    return gni_host_inet_numeric
      (tmpbuf, sa, addrlen, host, hostlen, flags);
}

/* Convert AF_LOCAL socket address, host part.   */
static int
gni_host_local (struct scratch_buffer *tmpbuf,
		const struct sockaddr *sa, socklen_t addrlen,
		char *host, socklen_t hostlen, int flags)
{
  if (!(flags & NI_NUMERICHOST))
    {
      struct utsname utsname;
      if (uname (&utsname) == 0)
	return checked_copy (host, hostlen, utsname.nodename);
    }

  if (flags & NI_NAMEREQD)
    return EAI_NONAME;

  return checked_copy (host, hostlen, "localhost");
}

/* Convert the host part of an AF_LOCAK socket address.   */
static int
gni_host (struct scratch_buffer *tmpbuf,
	  const struct sockaddr *sa, socklen_t addrlen,
	  char *host, socklen_t hostlen, int flags)
{
  switch (sa->sa_family)
    {
    case AF_INET:
    case AF_INET6:
      return gni_host_inet (tmpbuf, sa, addrlen, host, hostlen, flags);

    case AF_LOCAL:
      return gni_host_local (tmpbuf, sa, addrlen, host, hostlen, flags);

    default:
      return EAI_FAMILY;
    }
}

/* Convert service to string, AF_INET and AF_INET6 variant.  */
static int
gni_serv_inet (struct scratch_buffer *tmpbuf,
	       const struct sockaddr *sa, socklen_t addrlen,
	       char *serv, socklen_t servlen, int flags)
{
  _Static_assert
    (offsetof (struct sockaddr_in, sin_port)
     == offsetof (struct sockaddr_in6, sin6_port)
     && sizeof (((struct sockaddr_in) {}).sin_port) == sizeof (in_port_t)
     && sizeof (((struct sockaddr_in6) {}).sin6_port) == sizeof (in_port_t),
     "AF_INET and AF_INET6 port consistency");
  const struct sockaddr_in *sinp = (const struct sockaddr_in *) sa;
  if (!(flags & NI_NUMERICSERV))
    {
      struct servent *s, ts;
      int e;
      while ((e = __getservbyport_r (sinp->sin_port,
				     ((flags & NI_DGRAM)
				      ? "udp" : "tcp"), &ts,
				     tmpbuf->data, tmpbuf->length, &s)))
	{
	  if (e == ERANGE)
	    {
	      if (!scratch_buffer_grow (tmpbuf))
		return EAI_MEMORY;
	    }
	  else
	    break;
	}
      if (s)
	return checked_copy (serv, servlen, s->s_name);
      /* Fall through to numeric conversion.  */
    }
  return CHECKED_SNPRINTF (serv, servlen, "%d", ntohs (sinp->sin_port));
}

/* Convert service to string, AF_LOCAL variant.  */
static int
gni_serv_local (struct scratch_buffer *tmpbuf,
	       const struct sockaddr *sa, socklen_t addrlen,
	       char *serv, socklen_t servlen, int flags)
{
  return checked_copy
    (serv, servlen, ((const struct sockaddr_un *) sa)->sun_path);
}

/* Convert service to string, dispatching to the implementations
   above.  */
static int
gni_serv (struct scratch_buffer *tmpbuf,
	  const struct sockaddr *sa, socklen_t addrlen,
	  char *serv, socklen_t servlen, int flags)
{
  switch (sa->sa_family)
    {
    case AF_INET:
    case AF_INET6:
      return gni_serv_inet (tmpbuf, sa, addrlen, serv, servlen, flags);
    case AF_LOCAL:
      return gni_serv_local (tmpbuf, sa, addrlen, serv, servlen, flags);
    default:
      return EAI_FAMILY;
    }
}

int
getnameinfo (const struct sockaddr *sa, socklen_t addrlen, char *host,
	     socklen_t hostlen, char *serv, socklen_t servlen,
	     int flags)
{
  if (flags & ~(NI_NUMERICHOST|NI_NUMERICSERV|NI_NOFQDN|NI_NAMEREQD|NI_DGRAM
		|NI_IDN|DEPRECATED_NI_IDN))
    return EAI_BADFLAGS;

  if (sa == NULL || addrlen < sizeof (sa_family_t))
    return EAI_FAMILY;

  if ((flags & NI_NAMEREQD) && host == NULL && serv == NULL)
    return EAI_NONAME;

  switch (sa->sa_family)
    {
    case AF_LOCAL:
      if (addrlen < (socklen_t) offsetof (struct sockaddr_un, sun_path))
	return EAI_FAMILY;
      break;
    case AF_INET:
      if (addrlen < sizeof (struct sockaddr_in))
	return EAI_FAMILY;
      break;
    case AF_INET6:
      if (addrlen < sizeof (struct sockaddr_in6))
	return EAI_FAMILY;
      break;
    default:
      return EAI_FAMILY;
    }

  struct scratch_buffer tmpbuf;
  scratch_buffer_init (&tmpbuf);

  if (host != NULL && hostlen > 0)
    {
      int result = gni_host (&tmpbuf, sa, addrlen, host, hostlen, flags);
      if (result != 0)
	{
	  scratch_buffer_free (&tmpbuf);
	  return result;
	}
    }

  if (serv && (servlen > 0))
    {
      int result = gni_serv (&tmpbuf, sa, addrlen, serv, servlen, flags);
      if (result != 0)
	{
	  scratch_buffer_free (&tmpbuf);
	  return result;
	}
    }

  scratch_buffer_free (&tmpbuf);
  return 0;
}
libc_hidden_def (getnameinfo)