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-rw-r--r--src/resolv/async_resolv_utils.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/src/resolv/async_resolv_utils.c b/src/resolv/async_resolv_utils.c
new file mode 100644
index 0000000..f86181b
--- /dev/null
+++ b/src/resolv/async_resolv_utils.c
@@ -0,0 +1,343 @@
+/*
+ Authors:
+ Pavel Březina <pbrezina@redhat.com>
+
+ Copyright (C) 2013 Red Hat
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string.h>
+#include <talloc.h>
+#include <tevent.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "util/util.h"
+#include "resolv/async_resolv.h"
+
+struct resolv_get_domain_state {
+ char *fqdn;
+ char *hostname;
+};
+
+static void resolv_get_domain_done(struct tevent_req *subreq);
+
+struct tevent_req *
+resolv_get_domain_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ struct resolv_ctx *resolv_ctx,
+ const char *hostname,
+ enum host_database *host_dbs,
+ enum restrict_family family_order)
+{
+ struct resolv_get_domain_state *state = NULL;
+ struct tevent_req *req = NULL;
+ struct tevent_req *subreq = NULL;
+ char system_hostname[HOST_NAME_MAX + 1];
+ errno_t ret;
+
+ req = tevent_req_create(mem_ctx, &state,
+ struct resolv_get_domain_state);
+ if (req == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "tevent_req_create() failed\n");
+ return NULL;
+ }
+
+ if (hostname == NULL) {
+ /* use system hostname */
+ ret = gethostname(system_hostname, sizeof(system_hostname));
+ if (ret) {
+ ret = errno;
+ DEBUG(SSSDBG_CRIT_FAILURE, "gethostname() failed: [%d]: %s\n",
+ ret, strerror(ret));
+ goto immediately;
+ }
+ system_hostname[HOST_NAME_MAX] = '\0';
+ hostname = system_hostname;
+ }
+
+ state->fqdn = NULL;
+ state->hostname = talloc_strdup(state, hostname);
+ if (state->hostname == NULL) {
+ ret = ENOMEM;
+ goto immediately;
+ }
+
+ DEBUG(SSSDBG_TRACE_LIBS, "Host name is: %s\n", state->hostname);
+
+ subreq = resolv_gethostbyname_send(state, ev, resolv_ctx, state->hostname,
+ family_order, host_dbs);
+ if (subreq == NULL) {
+ talloc_zfree(req);
+ return NULL;
+ }
+
+ tevent_req_set_callback(subreq, resolv_get_domain_done, req);
+
+ return req;
+
+immediately:
+ tevent_req_error(req, ret);
+ tevent_req_post(req, ev);
+
+ return req;
+}
+
+static void resolv_get_domain_done(struct tevent_req *subreq)
+{
+ struct resolv_get_domain_state *state = NULL;
+ struct tevent_req *req = NULL;
+ struct resolv_hostent *rhostent;
+ int resolv_status;
+ errno_t ret;
+
+ req = tevent_req_callback_data(subreq, struct tevent_req);
+ state = tevent_req_data(req, struct resolv_get_domain_state);
+
+ ret = resolv_gethostbyname_recv(subreq, req, &resolv_status,
+ NULL, &rhostent);
+ talloc_zfree(subreq);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_OP_FAILURE,
+ "Could not get fully qualified name for host name %s "
+ "error [%d]: %s, resolver returned: [%d]: %s\n",
+ state->hostname, ret, strerror(ret), resolv_status,
+ resolv_strerror(resolv_status));
+ state->fqdn = state->hostname;
+ } else {
+ DEBUG(SSSDBG_TRACE_LIBS, "The FQDN is: %s\n", rhostent->name);
+ state->fqdn = talloc_steal(state, rhostent->name);
+ talloc_zfree(rhostent);
+ }
+
+ tevent_req_done(req);
+}
+
+errno_t resolv_get_domain_recv(TALLOC_CTX *mem_ctx,
+ struct tevent_req *req,
+ char **_dns_domain)
+{
+ struct resolv_get_domain_state *state = NULL;
+ char *dns_domain = NULL;
+ char *domptr = NULL;
+
+ state = tevent_req_data(req, struct resolv_get_domain_state);
+
+ TEVENT_REQ_RETURN_ON_ERROR(req);
+
+ domptr = strchr(state->fqdn, '.');
+ if (domptr == NULL || (*(domptr+1) == '\0')) {
+ /* If the FQDN did not contain a dot or the dot was the last character
+ * (broken DNS server perhaps) */
+ dns_domain = state->fqdn;
+ } else {
+ dns_domain = domptr + 1;
+ }
+
+ *_dns_domain = talloc_strdup(mem_ctx, dns_domain);
+ if (*_dns_domain == NULL) {
+ return ENOMEM;
+ }
+
+ return EOK;
+}
+
+struct resolv_discover_srv_state {
+ struct tevent_context *ev;
+ struct resolv_ctx *resolv_ctx;
+ const char *service;
+ const char *protocol;
+ const char **discovery_domains;
+ int domain_index;
+
+ struct ares_srv_reply *reply_list;
+ uint32_t ttl;
+};
+
+static errno_t resolv_discover_srv_next_domain(struct tevent_req *req);
+static void resolv_discover_srv_done(struct tevent_req *subreq);
+
+struct tevent_req *resolv_discover_srv_send(TALLOC_CTX *mem_ctx,
+ struct tevent_context *ev,
+ struct resolv_ctx *resolv_ctx,
+ const char *service,
+ const char *protocol,
+ const char **discovery_domains)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *req = NULL;
+ errno_t ret;
+
+ req = tevent_req_create(mem_ctx, &state,
+ struct resolv_discover_srv_state);
+ if (req == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "tevent_req_create() failed\n");
+ return NULL;
+ }
+
+ if (resolv_ctx == NULL || service == NULL || protocol == NULL
+ || discovery_domains == NULL) {
+ ret = EINVAL;
+ goto immediately;
+ }
+
+ state->ev = ev;
+ state->resolv_ctx = resolv_ctx;
+ state->discovery_domains = discovery_domains;
+ state->service = service;
+ state->protocol = protocol;
+ state->domain_index = 0;
+
+ ret = resolv_discover_srv_next_domain(req);
+ if (ret != EAGAIN) {
+ goto immediately;
+ }
+
+ return req;
+
+immediately:
+ if (ret == EOK) {
+ tevent_req_done(req);
+ } else {
+ tevent_req_error(req, ret);
+ }
+ tevent_req_post(req, ev);
+
+ return req;
+}
+
+static errno_t resolv_discover_srv_next_domain(struct tevent_req *req)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *subreq = NULL;
+ const char *domain = NULL;
+ char *query = NULL;
+ errno_t ret;
+
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ domain = state->discovery_domains[state->domain_index];
+ if (domain == NULL) {
+ ret = EOK;
+ goto done;
+ }
+
+ query = talloc_asprintf(state, "_%s._%s.%s", state->service,
+ state->protocol, domain);
+ if (query == NULL) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ DEBUG(SSSDBG_TRACE_FUNC, "SRV resolution of service '%s'. Will use DNS "
+ "discovery domain '%s'\n", state->service, domain);
+
+ subreq = resolv_getsrv_send(state, state->ev,
+ state->resolv_ctx, query);
+ if (subreq == NULL) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ tevent_req_set_callback(subreq, resolv_discover_srv_done, req);
+
+ state->domain_index++;
+ ret = EAGAIN;
+
+done:
+ if (ret != EAGAIN) {
+ talloc_free(query);
+ }
+
+ return ret;
+}
+
+static void resolv_discover_srv_done(struct tevent_req *subreq)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ struct tevent_req *req = NULL;
+ int status;
+ errno_t ret;
+
+ req = tevent_req_callback_data(subreq, struct tevent_req);
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ ret = resolv_getsrv_recv(state, subreq, &status, NULL,
+ &state->reply_list, &state->ttl);
+ talloc_zfree(subreq);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_OP_FAILURE, "SRV query failed [%d]: %s\n",
+ status, resolv_strerror(status));
+
+ if (status == ARES_ENOTFOUND) {
+ /* continue with next discovery domain */
+ ret = resolv_discover_srv_next_domain(req);
+ if (ret == EOK) {
+ /* there are no more domains to try */
+ ret = ENOENT;
+ }
+
+ goto done;
+ }
+
+ /* critical error when fetching SRV record */
+ ret = EIO;
+ goto done;
+ }
+
+done:
+ if (ret == EOK) {
+ tevent_req_done(req);
+ } else if (ret != EAGAIN) {
+ tevent_req_error(req, ret);
+ }
+
+ return;
+}
+
+errno_t resolv_discover_srv_recv(TALLOC_CTX *mem_ctx,
+ struct tevent_req *req,
+ struct ares_srv_reply **_reply_list,
+ uint32_t *_ttl,
+ char **_dns_domain)
+{
+ struct resolv_discover_srv_state *state = NULL;
+ char *domain = NULL;
+
+ state = tevent_req_data(req, struct resolv_discover_srv_state);
+
+ TEVENT_REQ_RETURN_ON_ERROR(req);
+
+ if (_dns_domain != NULL) {
+ /* domain_index now points to selected domain + 1 */
+ domain = talloc_strdup(mem_ctx,
+ state->discovery_domains[state->domain_index - 1]);
+ if (domain == NULL) {
+ return ENOMEM;
+ }
+
+ *_dns_domain = domain;
+ }
+
+ if (_reply_list != NULL) {
+ *_reply_list = talloc_steal(mem_ctx, state->reply_list);
+ }
+
+ if (_ttl != NULL) {
+ *_ttl = state->ttl;
+ }
+
+ return EOK;
+}
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