3 * Resolver library with GLib integration
5 * Copyright (C) 2009-2010 Intel Corporation. All rights reserved.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
31 #include <sys/types.h>
32 #include <sys/socket.h>
34 #include <arpa/inet.h>
35 #include <arpa/nameser.h>
39 struct resolv_lookup {
45 struct resolv_query *ipv4_query;
46 struct resolv_query *ipv6_query;
51 GResolvResultFunc result_func;
62 GResolvResultFunc result_func;
66 struct resolv_nameserver {
73 GIOChannel *udp_channel;
85 GList *nameserver_list;
87 struct __res_state res;
89 GResolvDebugFunc debug_func;
93 static inline void debug(GResolv *resolv, const char *format, ...)
98 if (resolv->debug_func == NULL)
101 va_start(ap, format);
103 if (vsnprintf(str, sizeof(str), format, ap) > 0)
104 resolv->debug_func(str, resolv->debug_data);
109 static void destroy_query(struct resolv_query *query)
111 if (query->timeout > 0)
112 g_source_remove(query->timeout);
117 static void destroy_lookup(struct resolv_lookup *lookup)
119 if (lookup->ipv4_query) {
120 destroy_query(lookup->ipv4_query);
121 g_queue_remove(lookup->resolv->query_queue, lookup->ipv4_query);
123 if (lookup->ipv6_query) {
124 destroy_query(lookup->ipv6_query);
125 g_queue_remove(lookup->resolv->query_queue, lookup->ipv4_query);
127 g_strfreev(lookup->results);
131 static gboolean query_timeout(gpointer user_data)
133 struct resolv_query *query = user_data;
134 GResolv *resolv = query->resolv;
138 if (query->result_func != NULL)
139 query->result_func(G_RESOLV_RESULT_STATUS_NO_RESPONSE,
140 NULL, query->result_data);
142 destroy_query(query);
143 g_queue_remove(resolv->query_queue, query);
148 static void free_nameserver(struct resolv_nameserver *nameserver)
150 if (nameserver == NULL)
153 if (nameserver->udp_watch > 0)
154 g_source_remove(nameserver->udp_watch);
156 if (nameserver->udp_channel != NULL)
157 g_io_channel_unref(nameserver->udp_channel);
159 g_free(nameserver->address);
163 static void flush_nameservers(GResolv *resolv)
167 for (list = g_list_first(resolv->nameserver_list);
168 list; list = g_list_next(list))
169 free_nameserver(list->data);
171 g_list_free(resolv->nameserver_list);
172 resolv->nameserver_list = NULL;
175 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
179 if (resolv->nameserver_list == NULL)
182 for (list = g_list_first(resolv->nameserver_list);
183 list; list = g_list_next(list)) {
184 struct resolv_nameserver *nameserver = list->data;
187 if (nameserver->udp_channel == NULL)
190 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
192 sent = send(sk, buf, len, 0);
198 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
200 const struct resolv_lookup *lookup = a;
201 guint id = GPOINTER_TO_UINT(b);
212 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
214 const struct resolv_query *query = a;
215 uint16_t msgid = GPOINTER_TO_UINT(b);
217 if (query->msgid < msgid)
220 if (query->msgid > msgid)
226 static void parse_response(struct resolv_nameserver *nameserver,
227 const unsigned char *buf, int len)
229 GResolv *resolv = nameserver->resolv;
230 GResolvResultStatus status;
235 int i, n, rcode, count;
237 debug(resolv, "response from %s", nameserver->address);
239 ns_initparse(buf, len, &msg);
241 rcode = ns_msg_getflag(msg, ns_f_rcode);
242 count = ns_msg_count(msg, ns_s_an);
244 debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
245 ns_msg_id(msg), rcode, count);
249 status = G_RESOLV_RESULT_STATUS_SUCCESS;
252 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
255 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
258 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
261 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
264 status = G_RESOLV_RESULT_STATUS_REFUSED;
267 status = G_RESOLV_RESULT_STATUS_ERROR;
271 results = g_try_new(char *, count + 1);
275 for (i = 0, n = 0; i < count; i++) {
278 ns_parserr(&msg, ns_s_an, i, &rr);
280 if (ns_rr_class(rr) != ns_c_in)
283 if (ns_rr_type(rr) == ns_t_a &&
284 ns_rr_rdlen(rr) == NS_INADDRSZ) {
285 inet_ntop(AF_INET, ns_rr_rdata(rr), result, sizeof(result));
286 } else if (ns_rr_type(rr) == ns_t_aaaa &&
287 ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
288 inet_ntop(AF_INET6, ns_rr_rdata(rr), result, sizeof(result));
292 results[n++] = g_strdup(result);
297 list = g_queue_find_custom(resolv->query_queue,
298 GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
301 struct resolv_query *query = list->data;
303 /* FIXME: This set of results is *only* for a single A or AAAA
304 query; we need to merge both results together and then sort
305 them according to RFC3484. While honouring /etc/gai.conf */
306 if (query->result_func != NULL)
307 query->result_func(status, results,
310 destroy_query(query);
311 g_queue_remove(resolv->query_queue, query);
317 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
320 struct resolv_nameserver *nameserver = user_data;
321 unsigned char buf[4096];
324 if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
325 nameserver->udp_watch = 0;
329 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
331 len = recv(sk, buf, sizeof(buf), 0);
335 parse_response(nameserver, buf, len);
340 static int connect_udp_channel(struct resolv_nameserver *nameserver)
342 struct addrinfo hints, *rp;
346 memset(&hints, 0, sizeof(hints));
347 hints.ai_family = AF_UNSPEC;
348 hints.ai_socktype = SOCK_DGRAM;
349 hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
351 sprintf(portnr, "%d", nameserver->port);
352 err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
356 /* Do not blindly copy this code elsewhere; it doesn't loop over the
357 results using ->ai_next as it should. That's OK in *this* case
358 because it was a numeric lookup; we *know* there's only one. */
362 sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
368 if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
376 nameserver->udp_channel = g_io_channel_unix_new(sk);
377 if (nameserver->udp_channel == NULL) {
382 g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
384 nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
385 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
386 received_udp_data, nameserver);
391 GResolv *g_resolv_new(int index)
398 resolv = g_try_new0(GResolv, 1);
402 resolv->ref_count = 1;
404 resolv->next_lookup_id = 1;
406 resolv->query_queue = g_queue_new();
407 if (resolv->query_queue == NULL) {
412 resolv->lookup_queue = g_queue_new();
413 if (resolv->lookup_queue == NULL) {
414 g_queue_free(resolv->query_queue);
419 resolv->index = index;
420 resolv->nameserver_list = NULL;
422 res_ninit(&resolv->res);
427 GResolv *g_resolv_ref(GResolv *resolv)
432 g_atomic_int_inc(&resolv->ref_count);
437 void g_resolv_unref(GResolv *resolv)
439 struct resolv_query *query;
444 if (g_atomic_int_dec_and_test(&resolv->ref_count) == FALSE)
447 while ((query = g_queue_pop_head(resolv->query_queue)))
448 destroy_query(query);
450 g_queue_free(resolv->query_queue);
451 g_queue_free(resolv->lookup_queue);
453 flush_nameservers(resolv);
455 res_nclose(&resolv->res);
460 void g_resolv_set_debug(GResolv *resolv,
461 GResolvDebugFunc func, gpointer user_data)
466 resolv->debug_func = func;
467 resolv->debug_data = user_data;
470 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
471 uint16_t port, unsigned long flags)
473 struct resolv_nameserver *nameserver;
478 nameserver = g_try_new0(struct resolv_nameserver, 1);
479 if (nameserver == NULL)
482 nameserver->address = g_strdup(address);
483 nameserver->port = port;
484 nameserver->flags = flags;
486 if (connect_udp_channel(nameserver) < 0) {
487 free_nameserver(nameserver);
491 nameserver->resolv = resolv;
493 resolv->nameserver_list = g_list_append(resolv->nameserver_list,
496 debug(resolv, "setting nameserver %s", address);
501 void g_resolv_flush_nameservers(GResolv *resolv)
506 flush_nameservers(resolv);
509 static int count_results(char **results)
516 for (i = 0; results[i]; i++)
522 static void add_result(struct resolv_lookup *lookup, char **results)
524 int nr_new_results = count_results(results);
525 int nr_old_results = count_results(lookup->results);
526 GResolvResultStatus status;
528 if (nr_new_results) {
529 lookup->results = g_realloc(lookup->results, sizeof(char *) *
530 (nr_new_results + nr_old_results + 1));
532 while (nr_new_results) {
533 lookup->results[nr_old_results++] = results[0];
538 lookup->results[nr_old_results] = NULL;
540 if (lookup->ipv4_query || lookup->ipv6_query)
543 /* FIXME: Sort results according to RFC3484 and /etc/gai.conf */
545 status = lookup->ipv4_status;
546 if (status == G_RESOLV_RESULT_STATUS_SUCCESS)
547 status = lookup->ipv6_status;
549 lookup->result_func(status, lookup->results, lookup->result_data);
551 g_queue_remove(lookup->resolv->lookup_queue, lookup);
552 destroy_lookup(lookup);
555 static void ipv4_result(GResolvResultStatus status, char **results, gpointer data)
557 struct resolv_lookup *lookup = data;
559 lookup->ipv4_status = status;
560 lookup->ipv4_query = NULL;
562 add_result(lookup, results);
565 static void ipv6_result(GResolvResultStatus status, char **results, gpointer data)
567 struct resolv_lookup *lookup = data;
569 lookup->ipv6_status = status;
570 lookup->ipv6_query = NULL;
572 add_result(lookup, results);
576 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
578 struct resolv_query *query = g_try_new0(struct resolv_query, 1);
579 unsigned char buf[4096];
585 len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
586 NULL, 0, NULL, buf, sizeof(buf));
588 query->msgid = buf[0] << 8 | buf[1];
590 query->result_data = lookup;
592 if (send_query(lookup->resolv, buf, len) < 0)
595 query->resolv = lookup->resolv;
597 g_queue_push_tail(lookup->resolv->query_queue, query);
599 query->timeout = g_timeout_add_seconds(5, query_timeout, query);
601 if (type == ns_t_aaaa) {
602 query->result_func = ipv6_result;
603 lookup->ipv6_query = query;
605 query->result_func = ipv4_result;
606 lookup->ipv4_query = query;
612 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
613 GResolvResultFunc func, gpointer user_data)
615 struct resolv_lookup *lookup;
617 debug(resolv, "lookup hostname %s", hostname);
622 if (resolv->nameserver_list == NULL) {
625 for (i = 0; i < resolv->res.nscount; i++) {
627 int family = resolv->res.nsaddr_list[i].sin_family;
628 void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
630 if (family != AF_INET && resolv->res._u._ext.nsaddrs[i]) {
632 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
634 if (family != AF_INET && family != AF_INET6)
637 if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
638 g_resolv_add_nameserver(resolv, buf, 53, 0);
641 if (resolv->nameserver_list == NULL)
642 g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
645 lookup = g_try_new0(struct resolv_lookup, 1);
649 lookup->resolv = resolv;
650 lookup->result_func = func;
651 lookup->result_data = user_data;
652 lookup->id = resolv->next_lookup_id++;
654 if (add_query(lookup, hostname, ns_t_a)) {
658 if (add_query(lookup, hostname, ns_t_aaaa)) {
659 destroy_query(lookup->ipv4_query);
660 g_queue_remove(resolv->query_queue, lookup->ipv4_query);
665 g_queue_push_tail(resolv->lookup_queue, lookup);
669 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
673 list = g_queue_find_custom(resolv->lookup_queue,
674 GUINT_TO_POINTER(id), compare_lookup_id);
679 destroy_lookup(list->data);
680 g_queue_remove(resolv->query_queue, list->data);