/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ /* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2008 Red Hat, Inc. * * This 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 of the License, or (at your option) any later version. * * This 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 this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. */ #include "config.h" #include #include "glibintl.h" #include "gresolver.h" #include "gnetworkingprivate.h" #include "gasyncresult.h" #include "ginetaddress.h" #include "ginetsocketaddress.h" #include "gsimpleasyncresult.h" #include "gsrvtarget.h" #ifdef G_OS_UNIX #include "gunixresolver.h" #endif #ifdef G_OS_WIN32 #include "gwin32resolver.h" #endif #include #include "gioalias.h" /** * SECTION:gresolver * @short_description: Asynchronous and cancellable DNS resolver * @include: gio/gio.h * * #GResolver provides cancellable synchronous and asynchronous DNS * resolution, for hostnames (g_resolver_lookup_by_address(), * g_resolver_lookup_by_name() and their async variants) and SRV * (service) records (g_resolver_lookup_service()). * * #GNetworkAddress and #GNetworkService provide wrappers around * #GResolver functionality that also implement #GSocketConnectable, * making it easy to connect to a remote host/service. */ /** * GResolver: * * The object that handles DNS resolution. Use g_resolver_get_default() * to get the default resolver. */ G_DEFINE_TYPE (GResolver, g_resolver, G_TYPE_OBJECT) static void g_resolver_class_init (GResolverClass *resolver_class) { volatile GType type; /* Make sure _g_networking_init() has been called */ type = g_inet_address_get_type (); /* Initialize _g_resolver_addrinfo_hints */ #ifdef AI_ADDRCONFIG _g_resolver_addrinfo_hints.ai_flags |= AI_ADDRCONFIG; #endif /* These two don't actually matter, they just get copied into the * returned addrinfo structures (and then we ignore them). But if * we leave them unset, we'll get back duplicate answers. */ _g_resolver_addrinfo_hints.ai_socktype = SOCK_STREAM; _g_resolver_addrinfo_hints.ai_protocol = IPPROTO_TCP; } static void g_resolver_init (GResolver *resolver) { } static GResolver *default_resolver; /** * g_resolver_get_default: * * Gets the default #GResolver. You should unref it when you are done * with it. #GResolver may use its reference count as a hint about how * many threads/processes, etc it should allocate for concurrent DNS * resolutions. * * Return value: the #GResolver. * * Since: 2.22 **/ GResolver * g_resolver_get_default (void) { if (!default_resolver) { if (g_thread_supported ()) default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL); else { #if defined(G_OS_UNIX) default_resolver = g_object_new (G_TYPE_UNIX_RESOLVER, NULL); #elif defined(G_OS_WIN32) default_resolver = g_object_new (G_TYPE_WIN32_RESOLVER, NULL); #endif } } return g_object_ref (default_resolver); } /** * g_resolver_set_default: * @resolver: the new default #GResolver * * Sets @resolver to be the application's default resolver (reffing * @resolver, and unreffing the previous default resolver, if any). * Future calls to g_resolver_get_default() will return this resolver. * * This can be used if an application wants to perform any sort of DNS * caching or "pinning"; it can implement its own #GResolver that * calls the original default resolver for DNS operations, and * implements its own cache policies on top of that, and then set * itself as the default resolver for all later code to use. * * Since: 2.22 */ void g_resolver_set_default (GResolver *resolver) { if (default_resolver) g_object_unref (default_resolver); default_resolver = g_object_ref (resolver); } /** * g_resolver_lookup_by_name: * @resolver: a #GResolver * @hostname: the hostname to look up * @cancellable: a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously resolves @hostname to determine its associated IP * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or * the textual form of an IP address (in which case this just becomes * a wrapper around g_inet_address_new_from_string()). * * On success, g_resolver_lookup_by_name() will return a #GList of * #GInetAddress, sorted in order of preference. (That is, you should * attempt to connect to the first address first, then the second if * the first fails, etc.) * * If the DNS resolution fails, @error (if non-%NULL) will be set to a * value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * If you are planning to connect to a socket on the resolved IP * address, it may be easier to create a #GNetworkAddress and use its * #GSocketConnectable interface. * * Return value: a #GList of #GInetAddress, or %NULL on error. You * must unref each of the addresses and free the list when you are * done with it. (You can use g_resolver_free_addresses() to do this.) * * Since: 2.22 */ GList * g_resolver_lookup_by_name (GResolver *resolver, const gchar *hostname, GCancellable *cancellable, GError **error) { GInetAddress *addr; GList *addrs; gchar *ascii_hostname = NULL; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (hostname != NULL, NULL); /* Check if @hostname is just an IP address */ addr = g_inet_address_new_from_string (hostname); if (addr) return g_list_append (NULL, addr); if (g_hostname_is_non_ascii (hostname)) hostname = ascii_hostname = g_hostname_to_ascii (hostname); addrs = G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name (resolver, hostname, cancellable, error); g_free (ascii_hostname); return addrs; } /** * g_resolver_lookup_by_name_async: * @resolver: a #GResolver * @hostname: the hostname to look up the address of * @cancellable: a #GCancellable, or %NULL * @callback: callback to call after resolution completes * @user_data: data for @callback * * Begins asynchronously resolving @hostname to determine its * associated IP address(es), and eventually calls @callback, which * must call g_resolver_lookup_by_name_finish() to get the result. * See g_resolver_lookup_by_name() for more details. * * Since: 2.22 */ void g_resolver_lookup_by_name_async (GResolver *resolver, const gchar *hostname, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GInetAddress *addr; gchar *ascii_hostname = NULL; g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (hostname != NULL); /* Check if @hostname is just an IP address */ addr = g_inet_address_new_from_string (hostname); if (addr) { GSimpleAsyncResult *simple; GList *addrs; simple = g_simple_async_result_new (G_OBJECT (resolver), callback, user_data, g_resolver_lookup_by_name_async); addrs = g_list_append (NULL, addr); g_simple_async_result_set_op_res_gpointer (simple, addrs, (GDestroyNotify)g_resolver_free_addresses); g_simple_async_result_complete_in_idle (simple); g_object_unref (simple); return; } if (g_hostname_is_non_ascii (hostname)) hostname = ascii_hostname = g_hostname_to_ascii (hostname); G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name_async (resolver, hostname, cancellable, callback, user_data); g_free (ascii_hostname); } /** * g_resolver_lookup_by_name_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a call to * g_resolver_lookup_by_name_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: a #GList of #GInetAddress, or %NULL on error. See * g_resolver_lookup_by_name() for more details. * * Since: 2.22 */ GList * g_resolver_lookup_by_name_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (G_IS_SIMPLE_ASYNC_RESULT (result)) { GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result); if (g_simple_async_result_propagate_error (simple, error)) return NULL; /* Handle the stringified-IP-addr case */ if (g_simple_async_result_get_source_tag (simple) == g_resolver_lookup_by_name_async) { GList *addrs; addrs = g_simple_async_result_get_op_res_gpointer (simple); g_simple_async_result_set_op_res_gpointer (simple, NULL, NULL); return addrs; } } return G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name_finish (resolver, result, error); } /** * g_resolver_free_addresses: * @addresses: a #GList of #GInetAddress * * Frees @addresses (which should be the return value from * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()). * (This is a convenience method; you can also simply free the results * by hand.) * * Since: 2.22 */ void g_resolver_free_addresses (GList *addresses) { GList *a; for (a = addresses; a; a = a->next) g_object_unref (a->data); g_list_free (addresses); } /** * g_resolver_lookup_by_address: * @resolver: a #GResolver * @address: the address to reverse-resolve * @cancellable: a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously reverse-resolves @address to determine its * associated hostname. * * If the DNS resolution fails, @error (if non-%NULL) will be set to * a value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * Return value: a hostname (either ASCII-only, or in ASCII-encoded * form), or %NULL on error. * * Since: 2.22 */ gchar * g_resolver_lookup_by_address (GResolver *resolver, GInetAddress *address, GCancellable *cancellable, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL); return G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address (resolver, address, cancellable, error); } /** * g_resolver_lookup_by_address_async: * @resolver: a #GResolver * @address: the address to reverse-resolve * @cancellable: a #GCancellable, or %NULL * @callback: callback to call after resolution completes * @user_data: data for @callback * * Begins asynchronously reverse-resolving @address to determine its * associated hostname, and eventually calls @callback, which must * call g_resolver_lookup_by_address_finish() to get the final result. * * Since: 2.22 */ void g_resolver_lookup_by_address_async (GResolver *resolver, GInetAddress *address, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (G_IS_INET_ADDRESS (address)); G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address_async (resolver, address, cancellable, callback, user_data); } /** * g_resolver_lookup_by_address_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a previous call to * g_resolver_lookup_by_address_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: a hostname (either ASCII-only, or in ASCII-encoded * form), or %NULL on error. * * Since: 2.22 */ gchar * g_resolver_lookup_by_address_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (G_IS_SIMPLE_ASYNC_RESULT (result)) { GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result); if (g_simple_async_result_propagate_error (simple, error)) return NULL; } return G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address_finish (resolver, result, error); } static gchar * g_resolver_get_service_rrname (const char *service, const char *protocol, const char *domain) { gchar *rrname, *ascii_domain = NULL; if (g_hostname_is_non_ascii (domain)) domain = ascii_domain = g_hostname_to_ascii (domain); rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain); g_free (ascii_domain); return rrname; } /** * g_resolver_lookup_service: * @resolver: a #GResolver * @service: the service type to look up (eg, "ldap") * @protocol: the networking protocol to use for @service (eg, "tcp") * @domain: the DNS domain to look up the service in * @cancellable: a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously performs a DNS SRV lookup for the given @service and * @protocol in the given @domain and returns an array of #GSrvTarget. * @domain may be an ASCII-only or UTF-8 hostname. Note also that the * @service and @protocol arguments do not * include the leading underscore that appears in the actual DNS * entry. * * On success, g_resolver_lookup_service() will return a #GList of * #GSrvTarget, sorted in order of preference. (That is, you should * attempt to connect to the first target first, then the second if * the first fails, etc.) * * If the DNS resolution fails, @error (if non-%NULL) will be set to * a value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * If you are planning to connect to the service, it is usually easier * to create a #GNetworkService and use its #GSocketConnectable * interface. * * Return value: a #GList of #GSrvTarget, or %NULL on error. You must * free each of the targets and the list when you are done with it. * (You can use g_resolver_free_targets() to do this.) * * Since: 2.22 */ GList * g_resolver_lookup_service (GResolver *resolver, const gchar *service, const gchar *protocol, const gchar *domain, GCancellable *cancellable, GError **error) { GList *targets; gchar *rrname; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (service != NULL, NULL); g_return_val_if_fail (protocol != NULL, NULL); g_return_val_if_fail (domain != NULL, NULL); rrname = g_resolver_get_service_rrname (service, protocol, domain); targets = G_RESOLVER_GET_CLASS (resolver)-> lookup_service (resolver, rrname, cancellable, error); g_free (rrname); return targets; } /** * g_resolver_lookup_service_async: * @resolver: a #GResolver * @service: the service type to look up (eg, "ldap") * @protocol: the networking protocol to use for @service (eg, "tcp") * @domain: the DNS domain to look up the service in * @cancellable: a #GCancellable, or %NULL * @callback: callback to call after resolution completes * @user_data: data for @callback * * Begins asynchronously performing a DNS SRV lookup for the given * @service and @protocol in the given @domain, and eventually calls * @callback, which must call g_resolver_lookup_service_finish() to * get the final result. See g_resolver_lookup_service() for more * details. * * Since: 2.22 */ void g_resolver_lookup_service_async (GResolver *resolver, const gchar *service, const gchar *protocol, const gchar *domain, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { gchar *rrname; g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (service != NULL); g_return_if_fail (protocol != NULL); g_return_if_fail (domain != NULL); rrname = g_resolver_get_service_rrname (service, protocol, domain); G_RESOLVER_GET_CLASS (resolver)-> lookup_service_async (resolver, rrname, cancellable, callback, user_data); g_free (rrname); } /** * g_resolver_lookup_service_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a previous call to * g_resolver_lookup_service_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: a #GList of #GSrvTarget, or %NULL on error. See * g_resolver_lookup_service() for more details. * * Since: 2.22 */ GList * g_resolver_lookup_service_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (G_IS_SIMPLE_ASYNC_RESULT (result)) { GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result); if (g_simple_async_result_propagate_error (simple, error)) return NULL; } return G_RESOLVER_GET_CLASS (resolver)-> lookup_service_finish (resolver, result, error); } /** * g_resolver_free_targets: * @targets: a #GList of #GSrvTarget * * Frees @targets (which should be the return value from * g_resolver_lookup_service() or g_resolver_lookup_service_finish()). * (This is a convenience method; you can also simply free the * results by hand.) * * Since: 2.22 */ void g_resolver_free_targets (GList *targets) { GList *t; for (t = targets; t; t = t->next) g_srv_target_free (t->data); g_list_free (targets); } /** * g_resolver_error_quark: * * Gets the #GResolver Error Quark. * * Return value: a #GQuark. * * Since: 2.22 */ GQuark g_resolver_error_quark (void) { return g_quark_from_static_string ("g-resolver-error-quark"); } static GResolverError g_resolver_error_from_addrinfo_error (gint err) { switch (err) { case EAI_FAIL: case EAI_NODATA: case EAI_NONAME: return G_RESOLVER_ERROR_NOT_FOUND; case EAI_AGAIN: return G_RESOLVER_ERROR_TEMPORARY_FAILURE; default: return G_RESOLVER_ERROR_INTERNAL; } } struct addrinfo _g_resolver_addrinfo_hints; /* Private method to process a getaddrinfo() response. */ GList * _g_resolver_addresses_from_addrinfo (const char *hostname, struct addrinfo *res, gint gai_retval, GError **error) { struct addrinfo *ai; GSocketAddress *sockaddr; GInetAddress *addr; GList *addrs; if (gai_retval != 0) { g_set_error (error, G_RESOLVER_ERROR, g_resolver_error_from_addrinfo_error (gai_retval), _("Error resolving '%s': %s"), hostname, gai_strerror (gai_retval)); return NULL; } g_return_val_if_fail (res != NULL, NULL); addrs = NULL; for (ai = res; ai; ai = ai->ai_next) { sockaddr = g_socket_address_new_from_native (ai->ai_addr, ai->ai_addrlen); if (!sockaddr || !G_IS_INET_SOCKET_ADDRESS (sockaddr)) continue; addr = g_object_ref (g_inet_socket_address_get_address ((GInetSocketAddress *)sockaddr)); addrs = g_list_prepend (addrs, addr); g_object_unref (sockaddr); } return g_list_reverse (addrs); } /* Private method to set up a getnameinfo() request */ void _g_resolver_address_to_sockaddr (GInetAddress *address, struct sockaddr_storage *sa, gsize *sa_len) { GSocketAddress *sockaddr; sockaddr = g_inet_socket_address_new (address, 0); g_socket_address_to_native (sockaddr, (struct sockaddr *)sa, sizeof (*sa), NULL); *sa_len = g_socket_address_get_native_size (sockaddr); g_object_unref (sockaddr); } /* Private method to process a getnameinfo() response. */ char * _g_resolver_name_from_nameinfo (GInetAddress *address, const gchar *name, gint gni_retval, GError **error) { if (gni_retval != 0) { gchar *phys; phys = g_inet_address_to_string (address); g_set_error (error, G_RESOLVER_ERROR, g_resolver_error_from_addrinfo_error (gni_retval), _("Error reverse-resolving '%s': %s"), phys ? phys : "(unknown)", gai_strerror (gni_retval)); g_free (phys); return NULL; } return g_strdup (name); } #if defined(G_OS_UNIX) /* Private method to process a res_query response into GSrvTargets */ GList * _g_resolver_targets_from_res_query (const gchar *rrname, guchar *answer, gint len, gint herr, GError **error) { gint count; gchar namebuf[1024]; guchar *end, *p; guint16 type, qclass, rdlength, priority, weight, port; guint32 ttl; HEADER *header; GSrvTarget *target; GList *targets; if (len <= 0) { GResolverError errnum; const gchar *format; if (len == 0 || herr == HOST_NOT_FOUND || herr == NO_DATA) { errnum = G_RESOLVER_ERROR_NOT_FOUND; format = _("No service record for '%s'"); } else if (herr == TRY_AGAIN) { errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE; format = _("Temporarily unable to resolve '%s'"); } else { errnum = G_RESOLVER_ERROR_INTERNAL; format = _("Error resolving '%s'"); } g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname); return NULL; } targets = NULL; header = (HEADER *)answer; p = answer + sizeof (HEADER); end = answer + len; /* Skip query */ count = ntohs (header->qdcount); while (count-- && p < end) { p += dn_expand (answer, end, p, namebuf, sizeof (namebuf)); p += 4; } /* Read answers */ count = ntohs (header->ancount); while (count-- && p < end) { p += dn_expand (answer, end, p, namebuf, sizeof (namebuf)); GETSHORT (type, p); GETSHORT (qclass, p); GETLONG (ttl, p); GETSHORT (rdlength, p); if (type != T_SRV || qclass != C_IN) { p += rdlength; continue; } GETSHORT (priority, p); GETSHORT (weight, p); GETSHORT (port, p); p += dn_expand (answer, end, p, namebuf, sizeof (namebuf)); target = g_srv_target_new (namebuf, port, priority, weight); targets = g_list_prepend (targets, target); } return g_srv_target_list_sort (targets); } #elif defined(G_OS_WIN32) /* Private method to process a DnsQuery response into GSrvTargets */ GList * _g_resolver_targets_from_DnsQuery (const gchar *rrname, DNS_STATUS status, DNS_RECORD *results, GError **error) { DNS_RECORD *rec; GSrvTarget *target; GList *targets; if (status != ERROR_SUCCESS) { GResolverError errnum; const gchar *format; if (status == DNS_ERROR_RCODE_NAME_ERROR) { errnum = G_RESOLVER_ERROR_NOT_FOUND; format = _("No service record for '%s'"); } else if (status == DNS_ERROR_RCODE_SERVER_FAILURE) { errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE; format = _("Temporarily unable to resolve '%s'"); } else { errnum = G_RESOLVER_ERROR_INTERNAL; format = _("Error resolving '%s'"); } g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname); return NULL; } targets = NULL; for (rec = results; rec; rec = rec->pNext) { if (rec->wType != DNS_TYPE_SRV) continue; target = g_srv_target_new (rec->Data.SRV.pNameTarget, rec->Data.SRV.wPort, rec->Data.SRV.wPriority, rec->Data.SRV.wWeight); targets = g_list_prepend (targets, target); } return g_srv_target_list_sort (targets); } #endif #define __G_RESOLVER_C__ #include "gioaliasdef.c"