DNS sites support - SRV lookup plugin interface

https://fedorahosted.org/sssd/ticket/1032

Introduces two new error codes:
- ERR_SRV_NOT_FOUND
- ERR_SRV_LOOKUP_ERROR

Since id_provider is authoritative in case of SRV plugin choise,
ability to override the selected pluging during runtime is not
desirable. We rely on the fact that id_provider is initialized
before all other providers, thus the plugin is set correctly.

1 files changed, 72 insertions, 0 deletions

diff --git a/src/providers/fail_over_srv.h b/src/providers/fail_over_srv.h
new file mode 100644
index 000000000..0796ad5ab
--- /dev/null
+++ b/src/providers/fail_over_srv.h
@@ -0,0 +1,72 @@
+/*
+    Authors:
+        Pavel B??ezina <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/>.
+*/
+
+#ifndef __FAIL_OVER_SRV_H__
+#define __FAIL_OVER_SRV_H__
+
+#include <talloc.h>
+#include <tevent.h>
+
+#include "resolv/async_resolv.h"
+
+/* SRV lookup plugin interface */
+
+struct fo_server_info {
+    char *host;
+    int port;
+};
+
+/*
+ * If discovery_domain is NULL, it should be detected automatically.
+ */
+typedef struct tevent_req *
+(*fo_srv_lookup_plugin_send_t)(TALLOC_CTX *mem_ctx,
+                               struct tevent_context *ev,
+                               const char *service,
+                               const char *protocol,
+                               const char *discovery_domain,
+                               void *pvt);
+
+/*
+ * Returns:
+ *   EOK - at least one primary or backup server was found
+ *   ERR_SRV_NOT_FOUND - no primary nor backup server found
+ *   ERR_SRV_LOOKUP_ERROR - error communicating with SRV database
+ *   other code - depends on plugin
+ *
+ * If EOK is returned:
+ * - and no primary server is found:
+ *   *_primary_servers = NULL
+ *   *_num_primary_servers = 0
+ * - and no backup server is found:
+ *   *_backup_servers = NULL
+ *   *_num_backup_servers = 0
+ * - *_dns_domain = DNS domain name where the servers were found
+ */
+typedef errno_t
+(*fo_srv_lookup_plugin_recv_t)(TALLOC_CTX *mem_ctx,
+                               struct tevent_req *req,
+                               char **_dns_domain,
+                               struct fo_server_info **_primary_servers,
+                               size_t *_num_primary_servers,
+                               struct fo_server_info **_backup_servers,
+                               size_t *_num_backup_servers);
+
+#endif /* __FAIL_OVER_SRV_H__ */