MDEV-26851 : Interface to monitor connections in Galera

Author: janlindstrom

CONTRIBUTORS.txt

@@ -21,6 +21,7 @@ Authors from Codership Oy:
  * Alexey Yurchenko <[email protected]>, Codership Oy
  * Mario Karuza <[email protected]>, Codership Oy
  * Daniele Sciascia <[email protected]>, Codership Oy
+ * Jan Lindström <[email protected]>, Codership Oy
  [Codership employees, add name and email/username above this line, but leave this line intact]
 
 Other contributors:

wsrep_connection_monitor_service.h

@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2024-2025 Codership Oy <[email protected]>
+ *
+ * This file is part of wsrep-API.
+ *
+ * Wsrep-API 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Wsrep-API 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 wsrep-API.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/** @file wsrep_connection_monitor_service.h
+ *
+ * This file defines interface for connection monitor service
+ *
+ * The provider which is capable of using the service interface v1 must
+ * export the following functions.
+ *
+ * int wsrep_init_connection_monitor_service_v1(wsrep_connection_monitor_service_v1_t*)
+ * void wsrep_deinit_connection_monitor_service_v1()
+ *
+ * which can be probed by the application.
+ *
+ * The application must initialize the service via above init function
+ * before the provider is initialized via wsrep->init(). The deinit
+ * function must be called after the provider side resources have been
+ * released via wsrep->free().
+ */
+
+#ifndef WSREP_CONNECTION_MONITOR_SERVICE_H
+#define WSREP_CONNECTION_MONITOR_SERVICE_H
+
+#include "wsrep_api.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif /* __cplusplus */
+
+/**
+ * Type tag for application defined connection monitoring processing context.
+ *
+ * Application may pass pointer to the context when initializing
+ * the connection monitor service. This pointer is passed a first parameter for
+ * each service call.
+ */
+typedef struct wsrep_connection_monitor_context wsrep_connection_monitor_context_t;
+
+typedef const void* wsrep_connection_key_t;
+
+/*
+ * Connection monitor connection update callbacks.
+ *
+ */
+
+/*
+ * Connection connect callback.
+ *
+ * @param id connection identifier
+ * @param scheme connection scheme (tcp, ssl)
+ * @param local_address local address string
+ * @param remote_address remote address string
+ */
+typedef void (*wsrep_connection_monitor_connect_cb_t)(
+    wsrep_connection_monitor_context_t*,
+    wsrep_connection_key_t id,
+    const wsrep_buf_t* scheme,
+    const wsrep_buf_t* local_address,
+    const wsrep_buf_t* remote_address);
+
+/*
+ * Connection disconnect callback.
+ *
+ * @param id connection identifier
+ */
+typedef void (*wsrep_connection_monitor_disconnect_cb_t)(
+    wsrep_connection_monitor_context_t*,
+    wsrep_connection_key_t id);
+
+/*
+ * Connection SSL/TLS info callback.
+ *
+ * @param id connection identifier
+ * @param cipher cipher suite name
+ * @param certificate_subject certificate subject name
+ * @param certificate_issuer certificate issuer name
+ * @param version SSL/TLS version string
+ */
+typedef void (*wsrep_connection_monitor_ssl_info_cb_t)(
+    wsrep_connection_monitor_context_t*,
+    wsrep_connection_key_t id,
+    const wsrep_buf_t* cipher,
+    const wsrep_buf_t* certificate_subject,
+    const wsrep_buf_t* certificate_issuer,
+    const wsrep_buf_t* version);
+
+/**
+ * Connection monitor service struct.
+ *
+ * A pointer to this struct must be passed to the call to
+ * wsrep_init_connection_monitor_service_v1.
+ *
+ * The application must provide implementation to all functions defined
+ * in this struct.
+ */
+typedef struct wsrep_connection_monitor_service_v1_st
+{
+    /* Connection monitor connect callback */
+    wsrep_connection_monitor_connect_cb_t connection_monitor_connect_cb;
+    /* Connection monitor disconnect callback */
+    wsrep_connection_monitor_disconnect_cb_t connection_monitor_disconnect_cb;
+    /* Connection monitor ssl info callback */
+    wsrep_connection_monitor_ssl_info_cb_t connection_monitor_ssl_info_cb;
+    /* Pointer to application defined connection monitor context. */
+    wsrep_connection_monitor_context_t* context;
+} wsrep_connection_monitor_service_v1_t;
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+
+#define WSREP_CONNECTION_MONITOR_SERVICE_INIT_FUNC_V1 "wsrep_init_connection_monitor_service_v1"
+#define WSREP_CONNECTION_MONITOR_SERVICE_DEINIT_FUNC_V1 "wsrep_deinit_connection_monitor_service_v1"
+
+#endif /* WSREP_CONNECTION_MONITOR_SERVICE_H */