2 This file is part of GNUnet.
3 (C) 2007-2013 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file util/gnunet-service-resolver.c
23 * @brief code to do DNS resolution
24 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
28 #include "gnunet_protocols.h"
29 #include "gnunet_statistics_service.h"
33 * A cached DNS lookup result.
38 * This is a doubly linked list.
43 * This is a doubly linked list.
48 * Hostname in human-readable form.
53 * Binary IP address, allocated at the end of this struct.
58 * Last time this entry was updated.
60 struct GNUNET_TIME_Absolute last_refresh;
63 * Last time this entry was requested.
65 struct GNUNET_TIME_Absolute last_request;
68 * Number of bytes in ip.
73 * Address family of the IP.
80 * Start of the linked list of cached DNS lookup results.
82 static struct IPCache *cache_head;
85 * Tail of the linked list of cached DNS lookup results.
87 static struct IPCache *cache_tail;
92 * Resolve the given request using getnameinfo
94 * @param cache the request to resolve (and where to store the result)
97 getnameinfo_resolve (struct IPCache *cache)
100 const struct sockaddr *sa;
101 struct sockaddr_in v4;
102 struct sockaddr_in6 v6;
108 GNUNET_assert (cache->ip_len == sizeof (struct in_addr));
109 sa = (const struct sockaddr*) &v4;
110 memset (&v4, 0, sizeof (v4));
111 v4.sin_addr = * (const struct in_addr*) cache->ip;
112 v4.sin_family = AF_INET;
113 #if HAVE_SOCKADDR_IN_SIN_LEN
114 v4.sin_len = sizeof (v4);
119 GNUNET_assert (cache->ip_len == sizeof (struct in6_addr));
120 sa = (const struct sockaddr*) &v6;
121 memset (&v6, 0, sizeof (v6));
122 v6.sin6_addr = * (const struct in6_addr*) cache->ip;
123 v6.sin6_family = AF_INET6;
124 #if HAVE_SOCKADDR_IN_SIN_LEN
125 v6.sin6_len = sizeof (v6);
134 getnameinfo (sa, salen, hostname, sizeof (hostname), NULL,
136 cache->addr = GNUNET_strdup (hostname);
141 #if HAVE_GETHOSTBYADDR
143 * Resolve the given request using gethostbyaddr
145 * @param cache the request to resolve (and where to store the result)
148 gethostbyaddr_resolve (struct IPCache *cache)
152 ent = gethostbyaddr (cache->ip,
156 cache->addr = GNUNET_strdup (ent->h_name);
162 * Resolve the given request using the available methods.
164 * @param cache the request to resolve (and where to store the result)
167 cache_resolve (struct IPCache *cache)
170 if (cache->addr == NULL)
171 getnameinfo_resolve (cache);
173 #if HAVE_GETHOSTBYADDR
174 if (cache->addr == NULL)
175 gethostbyaddr_resolve (cache);
181 * Get an IP address as a string (works for both IPv4 and IPv6). Note
182 * that the resolution happens asynchronously and that the first call
183 * may not immediately result in the FQN (but instead in a
184 * human-readable IP address).
186 * @param client handle to the client making the request (for sending the reply)
187 * @param af AF_INET or AF_INET6
188 * @param ip 'struct in_addr' or 'struct in6_addr'
191 get_ip_as_string (struct GNUNET_SERVER_Client *client,
196 struct IPCache *next;
197 struct GNUNET_TIME_Absolute now;
198 struct GNUNET_SERVER_TransmitContext *tc;
204 ip_len = sizeof (struct in_addr);
207 ip_len = sizeof (struct in6_addr);
212 now = GNUNET_TIME_absolute_get ();
214 while ( (NULL != (pos = next)) &&
216 (pos->ip_len != ip_len) ||
217 (0 != memcmp (pos->ip, ip, ip_len))) )
220 if (GNUNET_TIME_absolute_get_duration (pos->last_request).rel_value_us <
221 60 * 60 * 1000 * 1000LL)
223 GNUNET_CONTAINER_DLL_remove (cache_head,
226 GNUNET_free_non_null (pos->addr);
233 pos->last_request = now;
234 if (GNUNET_TIME_absolute_get_duration (pos->last_request).rel_value_us <
235 60 * 60 * 1000 * 1000LL)
237 GNUNET_free_non_null (pos->addr);
244 pos = GNUNET_malloc (sizeof (struct IPCache) + ip_len);
246 memcpy (&pos[1], ip, ip_len);
247 pos->last_request = now;
248 pos->last_refresh = now;
249 pos->ip_len = ip_len;
251 GNUNET_CONTAINER_DLL_insert (cache_head,
256 tc = GNUNET_SERVER_transmit_context_create (client);
257 if (pos->addr != NULL)
258 GNUNET_SERVER_transmit_context_append_data (tc, pos->addr,
259 strlen (pos->addr) + 1,
260 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
261 GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
262 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
263 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
269 getaddrinfo_resolve (struct GNUNET_SERVER_TransmitContext *tc,
270 const char *hostname, int af)
273 struct addrinfo hints;
274 struct addrinfo *result;
275 struct addrinfo *pos;
278 /* Due to a bug, getaddrinfo will not return a mix of different families */
283 ret1 = getaddrinfo_resolve (tc, hostname, AF_INET);
284 ret2 = getaddrinfo_resolve (tc, hostname, AF_INET6);
285 if ((ret1 == GNUNET_OK) || (ret2 == GNUNET_OK))
287 if ((ret1 == GNUNET_SYSERR) || (ret2 == GNUNET_SYSERR))
288 return GNUNET_SYSERR;
293 memset (&hints, 0, sizeof (struct addrinfo));
294 hints.ai_family = af;
295 hints.ai_socktype = SOCK_STREAM; /* go for TCP */
297 if (0 != (s = getaddrinfo (hostname, NULL, &hints, &result)))
299 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Could not resolve `%s' (%s): %s\n"),
302 AF_INET) ? "IPv4" : ((af == AF_INET6) ? "IPv6" : "any"),
304 if ((s == EAI_BADFLAGS) || (s == EAI_MEMORY)
311 return GNUNET_NO; /* other function may still succeed */
312 return GNUNET_SYSERR;
315 return GNUNET_SYSERR;
316 for (pos = result; pos != NULL; pos = pos->ai_next)
318 switch (pos->ai_family)
321 GNUNET_SERVER_transmit_context_append_data (tc,
322 &((struct sockaddr_in*) pos->ai_addr)->sin_addr,
323 sizeof (struct in_addr),
324 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
327 GNUNET_SERVER_transmit_context_append_data (tc,
328 &((struct sockaddr_in6*) pos->ai_addr)->sin6_addr,
329 sizeof (struct in6_addr),
330 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
333 /* unsupported, skip */
337 freeaddrinfo (result);
343 #if HAVE_GETHOSTBYNAME2
345 gethostbyname2_resolve (struct GNUNET_SERVER_TransmitContext *tc,
346 const char *hostname, int af)
353 /* gethostbyname2() in plibc is a compat dummy that calls gethostbyname(). */
359 ret1 = gethostbyname2_resolve (tc, hostname, AF_INET);
360 ret2 = gethostbyname2_resolve (tc, hostname, AF_INET6);
361 if ((ret1 == GNUNET_OK) || (ret2 == GNUNET_OK))
363 if ((ret1 == GNUNET_SYSERR) || (ret2 == GNUNET_SYSERR))
364 return GNUNET_SYSERR;
367 hp = gethostbyname2 (hostname, af);
370 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
371 _("Could not find IP of host `%s': %s\n"), hostname,
372 hstrerror (h_errno));
373 return GNUNET_SYSERR;
375 GNUNET_assert (hp->h_addrtype == af);
379 GNUNET_assert (hp->h_length == sizeof (struct in_addr));
380 GNUNET_SERVER_transmit_context_append_data (tc,
383 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
386 GNUNET_assert (hp->h_length == sizeof (struct in6_addr));
387 GNUNET_SERVER_transmit_context_append_data (tc,
390 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
394 return GNUNET_SYSERR;
401 #if HAVE_GETHOSTBYNAME
403 gethostbyname_resolve (struct GNUNET_SERVER_TransmitContext *tc,
404 const char *hostname)
408 hp = GETHOSTBYNAME (hostname);
411 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
412 _("Could not find IP of host `%s': %s\n"), hostname,
413 hstrerror (h_errno));
414 return GNUNET_SYSERR;
416 if (hp->h_addrtype != AF_INET)
419 return GNUNET_SYSERR;
421 GNUNET_assert (hp->h_length == sizeof (struct in_addr));
422 GNUNET_SERVER_transmit_context_append_data (tc,
425 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
432 * Convert a string to an IP address.
434 * @param client where to send the IP address
435 * @param hostname the hostname to resolve
436 * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any"
439 get_ip_from_hostname (struct GNUNET_SERVER_Client *client, const char *hostname,
443 struct GNUNET_SERVER_TransmitContext *tc;
445 tc = GNUNET_SERVER_transmit_context_create (client);
448 if (ret == GNUNET_NO)
449 ret = getaddrinfo_resolve (tc, hostname, af);
451 #if HAVE_GETHOSTBYNAME2
452 if (ret == GNUNET_NO)
453 ret = gethostbyname2_resolve (tc, hostname, af);
455 #if HAVE_GETHOSTBYNAME
456 if ((ret == GNUNET_NO) && ((af == AF_UNSPEC) || (af == PF_INET)))
457 gethostbyname_resolve (tc, hostname);
459 GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
460 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
461 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
466 * Handle GET-message.
469 * @param client identification of the client
470 * @param message the actual message
473 handle_get (void *cls, struct GNUNET_SERVER_Client *client,
474 const struct GNUNET_MessageHeader *message)
477 const struct GNUNET_RESOLVER_GetMessage *msg;
483 msize = ntohs (message->size);
484 if (msize < sizeof (struct GNUNET_RESOLVER_GetMessage))
487 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
490 msg = (const struct GNUNET_RESOLVER_GetMessage *) message;
491 size = msize - sizeof (struct GNUNET_RESOLVER_GetMessage);
492 direction = ntohl (msg->direction);
493 af = ntohl (msg->af);
494 if (direction == GNUNET_NO)
496 /* IP from hostname */
497 const char *hostname;
499 hostname = (const char *) &msg[1];
500 if (hostname[size - 1] != '\0')
503 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
506 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Resolver asked to look up `%s'.\n",
508 get_ip_from_hostname (client, hostname, af);
515 if (size != sizeof (struct in_addr))
518 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
523 if (size != sizeof (struct in6_addr))
526 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
532 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
536 char buf[INET6_ADDRSTRLEN];
538 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
539 "Resolver asked to look up IP address `%s'.\n",
540 inet_ntop (af, ip, buf, sizeof (buf)));
542 get_ip_as_string (client, af, ip);
547 * Process resolver requests.
550 * @param server the initialized server
551 * @param cfg configuration to use
554 run (void *cls, struct GNUNET_SERVER_Handle *server,
555 const struct GNUNET_CONFIGURATION_Handle *cfg)
557 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
558 {&handle_get, NULL, GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST, 0},
561 GNUNET_SERVER_add_handlers (server, handlers);
566 * The main function for the resolver service.
568 * @param argc number of arguments from the command line
569 * @param argv command line arguments
570 * @return 0 ok, 1 on error
573 main (int argc, char *const *argv)
580 GNUNET_SERVICE_run (argc, argv, "resolver", GNUNET_SERVICE_OPTION_NONE,
581 &run, NULL)) ? 0 : 1;
582 while (NULL != (pos = cache_head))
584 GNUNET_CONTAINER_DLL_remove (cache_head,
587 GNUNET_free_non_null (pos->addr);
597 * MINIMIZE heap size (way below 128k) since this process doesn't need much.
599 void __attribute__ ((constructor)) GNUNET_ARM_memory_init ()
601 mallopt (M_TRIM_THRESHOLD, 4 * 1024);
602 mallopt (M_TOP_PAD, 1 * 1024);
608 /* end of gnunet-service-resolver.c */