2 This file is part of GNUnet.
3 (C) 2007, 2008, 2009 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 2, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
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_disk_lib.h"
28 #include "gnunet_getopt_lib.h"
29 #include "gnunet_protocols.h"
30 #include "gnunet_service_lib.h"
31 #include "gnunet_statistics_service.h"
32 #include "gnunet_strings_lib.h"
33 #include "gnunet_time_lib.h"
37 * A cached DNS lookup result.
42 * This is a linked list.
47 * Hostname in human-readable form.
52 * Hostname in binary format.
57 * Last time this entry was updated.
59 struct GNUNET_TIME_Absolute last_refresh;
62 * Last time this entry was requested.
64 struct GNUNET_TIME_Absolute last_request;
67 * Number of bytes in sa.
74 * Start of the linked list of cached DNS lookup results.
76 static struct IPCache *head;
81 * Resolve the given request using getnameinfo
83 * @param cache the request to resolve (and where to store the result)
86 getnameinfo_resolve (struct IPCache *cache)
90 if (0 == getnameinfo (cache->sa,
91 cache->salen, hostname, sizeof (hostname), NULL, 0, 0))
92 cache->addr = GNUNET_strdup (hostname);
97 #if HAVE_GETHOSTBYADDR
99 * Resolve the given request using gethostbyaddr
101 * @param cache the request to resolve (and where to store the result)
104 gethostbyaddr_resolve (struct IPCache *cache)
108 switch (cache->sa->sa_family)
111 ent = gethostbyaddr (&((struct sockaddr_in *) cache->sa)->sin_addr,
112 sizeof (struct in_addr), AF_INET);
115 ent = gethostbyaddr (&((struct sockaddr_in6 *) cache->sa)->sin6_addr,
116 sizeof (struct in6_addr), AF_INET6);
122 cache->addr = GNUNET_strdup (ent->h_name);
127 * Resolve the given request using the available methods.
129 * @param cache the request to resolve (and where to store the result)
132 cache_resolve (struct IPCache *cache)
135 if (cache->addr == NULL)
136 getnameinfo_resolve (cache);
138 #if HAVE_GETHOSTBYADDR
139 if (cache->addr == NULL)
140 gethostbyaddr_resolve (cache);
147 * Get an IP address as a string (works for both IPv4 and IPv6). Note
148 * that the resolution happens asynchronously and that the first call
149 * may not immediately result in the FQN (but instead in a
150 * human-readable IP address).
152 * @param client handle to the client making the request (for sending the reply)
153 * @param sa should be of type "struct sockaddr*"
154 * @param salen number of bytes in sa
157 get_ip_as_string (struct GNUNET_SERVER_Client *client,
158 const struct sockaddr *sa, socklen_t salen)
160 struct IPCache *cache;
161 struct IPCache *prev;
162 struct GNUNET_TIME_Absolute now;
163 struct GNUNET_SERVER_TransmitContext *tc;
165 if (salen < sizeof (struct sockaddr))
168 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
171 now = GNUNET_TIME_absolute_get ();
174 while ((cache != NULL) &&
175 ((cache->salen != salen) || (0 != memcmp (cache->sa, sa, salen))))
177 if (GNUNET_TIME_absolute_get_duration (cache->last_request).rel_value <
182 prev->next = cache->next;
183 GNUNET_free_non_null (cache->addr);
184 GNUNET_free (cache->sa);
191 GNUNET_free_non_null (cache->addr);
192 GNUNET_free (cache->sa);
203 cache->last_request = now;
204 if (GNUNET_TIME_absolute_get_duration (cache->last_request).rel_value <
207 GNUNET_free_non_null (cache->addr);
210 cache_resolve (cache);
215 cache = GNUNET_malloc (sizeof (struct IPCache));
217 cache->salen = salen;
218 cache->sa = GNUNET_malloc (salen);
219 memcpy (cache->sa, sa, salen);
220 cache->last_request = GNUNET_TIME_absolute_get ();
221 cache->last_refresh = GNUNET_TIME_absolute_get ();
223 cache_resolve (cache);
226 tc = GNUNET_SERVER_transmit_context_create (client);
227 if (cache->addr != NULL)
228 GNUNET_SERVER_transmit_context_append_data (tc,
230 strlen (cache->addr) + 1,
231 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
232 GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
233 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
234 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
240 getaddrinfo_resolve (struct GNUNET_SERVER_TransmitContext *tc,
241 const char *hostname, int domain)
244 struct addrinfo hints;
245 struct addrinfo *result;
246 struct addrinfo *pos;
248 memset (&hints, 0, sizeof (struct addrinfo));
251 hints.ai_family = domain;
253 hints.ai_family = AF_INET;
255 hints.ai_socktype = SOCK_STREAM; /* go for TCP */
257 if (0 != (s = getaddrinfo (hostname, NULL, &hints, &result)))
259 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
260 _("Could not resolve `%s' (%s): %s\n"), hostname,
262 AF_INET) ? "IPv4" : ((domain ==
263 AF_INET6) ? "IPv6" : "any"),
265 if ((s == EAI_BADFLAGS) || (s == EAI_MEMORY)
273 return GNUNET_NO; /* other function may still succeed */
274 return GNUNET_SYSERR;
277 return GNUNET_SYSERR;
281 GNUNET_SERVER_transmit_context_append_data (tc,
284 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
287 freeaddrinfo (result);
292 #if HAVE_GETHOSTBYNAME2
294 gethostbyname2_resolve (struct GNUNET_SERVER_TransmitContext *tc,
295 const char *hostname, int domain)
298 struct sockaddr_in a4;
299 struct sockaddr_in6 a6;
303 if (domain == AF_UNSPEC)
305 ret1 = gethostbyname2_resolve (tc, hostname, AF_INET);
306 ret2 = gethostbyname2_resolve (tc, hostname, AF_INET6);
307 if ((ret1 == GNUNET_OK) || (ret2 == GNUNET_OK))
309 if ((ret1 == GNUNET_SYSERR) || (ret2 == GNUNET_SYSERR))
310 return GNUNET_SYSERR;
313 hp = gethostbyname2 (hostname, domain);
316 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
317 _("Could not find IP of host `%s': %s\n"),
318 hostname, hstrerror (h_errno));
319 return GNUNET_SYSERR;
321 GNUNET_assert (hp->h_addrtype == domain);
322 if (domain == AF_INET)
324 GNUNET_assert (hp->h_length == sizeof (struct in_addr));
325 memset (&a4, 0, sizeof (a4));
326 a4.sin_family = AF_INET;
327 #if HAVE_SOCKADDR_IN_SIN_LEN
328 a4.sin_len = (u_char) sizeof (struct sockaddr_in);
330 memcpy (&a4.sin_addr, hp->h_addr_list[0], hp->h_length);
331 GNUNET_SERVER_transmit_context_append_data (tc,
334 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
338 GNUNET_assert (hp->h_length == sizeof (struct in6_addr));
339 memset (&a6, 0, sizeof (a6));
340 a6.sin6_family = AF_INET6;
341 #if HAVE_SOCKADDR_IN_SIN_LEN
342 a6.sin6_len = (u_char) sizeof (struct sockaddr_in6);
344 memcpy (&a6.sin6_addr, hp->h_addr_list[0], hp->h_length);
345 GNUNET_SERVER_transmit_context_append_data (tc,
348 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
354 #if HAVE_GETHOSTBYNAME
356 gethostbyname_resolve (struct GNUNET_SERVER_TransmitContext *tc,
357 const char *hostname)
360 struct sockaddr_in addr;
362 hp = GETHOSTBYNAME (hostname);
365 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
366 _("Could not find IP of host `%s': %s\n"),
367 hostname, hstrerror (h_errno));
368 return GNUNET_SYSERR;
370 if (hp->h_addrtype != AF_INET)
373 return GNUNET_SYSERR;
375 GNUNET_assert (hp->h_length == sizeof (struct in_addr));
376 memset (&addr, 0, sizeof (addr));
377 addr.sin_family = AF_INET;
378 #if HAVE_SOCKADDR_IN_SIN_LEN
379 addr.sin_len = (u_char) sizeof (struct sockaddr_in);
381 memcpy (&addr.sin_addr, hp->h_addr_list[0], hp->h_length);
382 GNUNET_SERVER_transmit_context_append_data (tc,
385 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
392 * Convert a string to an IP address.
394 * @param client where to send the IP address
395 * @param hostname the hostname to resolve
396 * @param domain AF_INET or AF_INET6; use AF_UNSPEC for "any"
399 get_ip_from_hostname (struct GNUNET_SERVER_Client *client,
400 const char *hostname, int domain)
403 struct GNUNET_SERVER_TransmitContext *tc;
405 tc = GNUNET_SERVER_transmit_context_create (client);
408 if (ret == GNUNET_NO)
409 ret = getaddrinfo_resolve (tc, hostname, domain);
411 #if HAVE_GETHOSTBYNAME2
412 if (ret == GNUNET_NO)
413 ret = gethostbyname2_resolve (tc, hostname, domain);
415 #if HAVE_GETHOSTBYNAME
416 if ((ret == GNUNET_NO) && ((domain == AF_UNSPEC) || (domain == PF_INET)))
417 gethostbyname_resolve (tc, hostname);
419 GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
420 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
421 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
426 * Handle GET-message.
429 * @param client identification of the client
430 * @param message the actual message
433 handle_get (void *cls,
434 struct GNUNET_SERVER_Client *client,
435 const struct GNUNET_MessageHeader *message)
438 const struct GNUNET_RESOLVER_GetMessage *msg;
439 const char *hostname;
440 const struct sockaddr *sa;
445 msize = ntohs (message->size);
446 if (msize < sizeof (struct GNUNET_RESOLVER_GetMessage))
449 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
452 msg = (const struct GNUNET_RESOLVER_GetMessage *) message;
453 size = msize - sizeof (struct GNUNET_RESOLVER_GetMessage);
454 direction = ntohl (msg->direction);
455 domain = ntohl (msg->domain);
456 if (direction == GNUNET_NO)
458 /* IP from hostname */
459 hostname = (const char *) &msg[1];
460 if (hostname[size - 1] != '\0')
463 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
467 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
468 _("Resolver asked to look up `%s'.\n"), hostname);
470 get_ip_from_hostname (client, hostname, domain);
475 char buf[INET6_ADDRSTRLEN];
477 if (size < sizeof (struct sockaddr))
480 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
483 sa = (const struct sockaddr *) &msg[1];
484 switch (sa->sa_family)
487 if (size != sizeof (struct sockaddr_in))
490 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
494 inet_ntop (AF_INET, sa, buf, size);
498 if (size != sizeof (struct sockaddr_in6))
501 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
505 inet_ntop (AF_INET6, sa, buf, size);
510 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
514 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
515 _("Resolver asked to look up IP address `%s'.\n"), buf);
517 get_ip_as_string (client, sa, size);
523 * Process resolver requests.
526 * @param server the initialized server
527 * @param cfg configuration to use
531 struct GNUNET_SERVER_Handle *server,
532 const struct GNUNET_CONFIGURATION_Handle *cfg)
534 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
535 {&handle_get, NULL, GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST, 0},
538 GNUNET_SERVER_add_handlers (server, handlers);
543 * The main function for the resolver service.
545 * @param argc number of arguments from the command line
546 * @param argv command line arguments
547 * @return 0 ok, 1 on error
550 main (int argc, char *const *argv)
556 GNUNET_SERVICE_run (argc,
558 "resolver", GNUNET_SERVICE_OPTION_NONE,
559 &run, NULL)) ? 0 : 1;
564 GNUNET_free_non_null (head->addr);
565 GNUNET_free (head->sa);
572 /* end of gnunet-service-resolver.c */