OVS link: rename "ovs_link" -> "ovs_events"

- Rename files

Change-Id: Ic662d5d673c1c66b2057e4b35fa3cf664e92825e
Signed-off-by: Mytnyk, VolodymyrX <volodymyrx.mytnyk@intel.com>

diff --git a/Makefile.am b/Makefile.am
index 76008d4c9fad6aca95fbb92c28c5da66a5d5414e..bee8112604eff36dd12069cf52a19b795ff672ee 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -1280,7 +1280,7 @@ endif
 
 if BUILD_PLUGIN_OVS_EVENTS
 pkglib_LTLIBRARIES += ovs_events.la
-ovs_events_la_SOURCES = ovs_link.c utils_ovs.c
+ovs_events_la_SOURCES = ovs_events.c utils_ovs.c
 ovs_events_la_LDFLAGS = $(PLUGIN_LDFLAGS) $(BUILD_WITH_LIBYAJL_LDFLAGS)
 ovs_events_la_CFLAGS = $(BUILD_WITH_LIBYAJL_CPPFLAGS)
 ovs_events_la_LIBADD = $(BUILD_WITH_LIBYAJL_LIBS)

diff --git a/src/ovs_events.c b/src/ovs_events.c
new file mode 100644 (file)
index 0000000..148fe92
--- /dev/null
+++ b/src/ovs_events.c
@@ -0,0 +1,503 @@
+/**
+ * collectd - src/ovs_events.c
+ *
+ * Copyright(c) 2016 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is furnished to do
+ * so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors:
+ *   Volodymyr Mytnyk <volodymyrx.mytnyk@intel.com>
+ **/
+
+#include "common.h"             /* auxiliary functions */
+
+#include "utils_ovs.h"          /* OVS helpers */
+
+#define OVS_EVENTS_PLUGIN "ovs_events"
+#define OVS_EVENTS_DEFAULT_OVS_DB_SERVER_URL "tcp:127.0.0.1:6640"
+#define OVS_EVENTS_CTX_LOCK for (int __i = ovs_events_ctx_lock(); __i != 0 ; \
+                                 __i = ovs_events_ctx_unlock())
+#define OVS_EVENTS_CONFIG_ERROR(option) do { \
+  ERROR(OVS_EVENTS_PLUGIN ": read '%s' config option failed", option); \
+  goto failure; } while (0)
+
+/* Link status type */
+enum ovs_events_link_status_e {DOWN, UP, UNKNOWN};
+typedef enum ovs_events_link_status_e ovs_events_link_status_t;
+
+/* Interface info */
+struct ovs_events_interface_info_s {
+  char *name;                   /* interface name */
+  ovs_events_link_status_t link_status; /* link status */
+  struct ovs_events_interface_info_s *next;     /* next interface info */
+};
+typedef struct ovs_events_interface_info_s ovs_events_interface_info_t;
+
+/* OVS events configuration data */
+struct ovs_events_config_s {
+  _Bool send_notification;      /* sent notification to collectd? */
+  char *ovs_db_server_url;      /* OVS DB server URL */
+};
+typedef struct ovs_events_config_s ovs_events_config_t;
+
+/* OVS events context type */
+struct ovs_events_ctx_s {
+  pthread_mutex_t mutex;        /* mutex to lock the context */
+  pthread_mutexattr_t mutex_attr;       /* context mutex attribute */
+  ovs_db_t *ovs_db;             /* pointer to OVS DB instance */
+  ovs_events_config_t config;   /* plugin config */
+  ovs_events_interface_info_t *ifaces;  /* interface info */
+};
+typedef struct ovs_events_ctx_s ovs_events_ctx_t;
+
+/*
+ * Private variables
+ */
+static ovs_events_ctx_t ovs_events_ctx = {
+  .mutex = PTHREAD_MUTEX_INITIALIZER,
+  .config = {
+             .send_notification = 0,    /* do not send notification */
+             .ovs_db_server_url = NULL},        /* use default OVS DB URL */
+  .ovs_db = NULL,
+  .ifaces = NULL};
+
+/* This function is used only by "OVS_EVENTS_CTX_LOCK" define (see above).
+ * It always returns 1 when context is locked.
+ */
+static inline int
+ovs_events_ctx_lock()
+{
+  pthread_mutex_lock(&ovs_events_ctx.mutex);
+  return (1);
+}
+
+/* This function is used only by "OVS_EVENTS_CTX_LOCK" define (see above).
+ * It always returns 0 when context is unlocked.
+ */
+static inline int
+ovs_events_ctx_unlock()
+{
+  pthread_mutex_unlock(&ovs_events_ctx.mutex);
+  return (0);
+}
+
+/* Update link status in OVS events context (cache) */
+static void
+ovs_events_link_status_update(const char *name,
+                              ovs_events_link_status_t status)
+{
+  OVS_EVENTS_CTX_LOCK {
+    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
+         iface = iface->next)
+      if (strcmp(iface->name, name) == 0)
+        iface->link_status = status;
+  }
+}
+
+/* Check if given interface name exists in configuration file. It
+ * returns 1 if exists otherwise 0. If no interfaces are configured,
+ * 1 is returned
+ */
+static int
+ovs_events_config_iface_exists(const char *ifname)
+{
+  int rc = 0;
+  OVS_EVENTS_CTX_LOCK {
+    if (!(rc = (ovs_events_ctx.ifaces == NULL))) {
+      for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
+           iface = iface->next)
+        if (rc = (strcmp(ifname, iface->name) == 0))
+          break;
+    }
+  }
+  return rc;
+}
+
+/* Release memory allocated for configuration data */
+static void
+ovs_events_config_free()
+{
+  ovs_events_interface_info_t *del_iface = NULL;
+  OVS_EVENTS_CTX_LOCK {
+    sfree(ovs_events_ctx.config.ovs_db_server_url);
+    while (ovs_events_ctx.ifaces) {
+      del_iface = ovs_events_ctx.ifaces;
+      ovs_events_ctx.ifaces = ovs_events_ctx.ifaces->next;
+      free(del_iface->name);
+      free(del_iface);
+    }
+  }
+}
+
+/* Parse plugin configuration file and store the config
+ * in allocated memory. Returns negative value in case of error.
+ */
+static int
+ovs_events_plugin_config(oconfig_item_t *ci)
+{
+  ovs_events_interface_info_t *new_iface;
+  char *if_name;
+
+  for (int i = 0; i < ci->children_num; i++) {
+    oconfig_item_t *child = ci->children + i;
+    if (strcasecmp("SendNotification", child->key) == 0) {
+      if (cf_util_get_boolean(child,
+                              &ovs_events_ctx.config.send_notification) < 0)
+        OVS_EVENTS_CONFIG_ERROR(child->key);
+    } else if (strcasecmp("OvsDbServerUrl", child->key) == 0) {
+      if (cf_util_get_string(child,
+                             &ovs_events_ctx.config.ovs_db_server_url) < 0)
+        OVS_EVENTS_CONFIG_ERROR(child->key);
+    } else if (strcasecmp("Interfaces", child->key) == 0) {
+      for (int j = 0; j < child->values_num; j++) {
+        /* check value type */
+        if (child->values[j].type != OCONFIG_TYPE_STRING) {
+          ERROR(OVS_EVENTS_PLUGIN
+                ": given interface name is not a string [idx=%d]", j);
+          goto failure;
+        }
+        /* get value */
+        if ((if_name = strdup(child->values[j].value.string)) == NULL) {
+          ERROR(OVS_EVENTS_PLUGIN " strdup() copy interface name fail");
+          goto failure;
+        }
+        if ((new_iface = malloc(sizeof(*new_iface))) == NULL) {
+          ERROR(OVS_EVENTS_PLUGIN ": malloc () copy interface name fail");
+          goto failure;
+        } else {
+          /* store interface name */
+          new_iface->name = if_name;
+          new_iface->link_status = UNKNOWN;
+          new_iface->next = ovs_events_ctx.ifaces;
+          ovs_events_ctx.ifaces = new_iface;
+          DEBUG(OVS_EVENTS_PLUGIN ": found monitored interface \"%s\"",
+                if_name);
+        }
+      }
+    } else {
+      ERROR(OVS_EVENTS_PLUGIN ": option '%s' is not allowed here",
+            child->key);
+      goto failure;
+    }
+  }
+  return (0);
+
+failure:
+  ovs_events_config_free();
+  return (-1);
+}
+
+/* Dispatch OVS interface link status event to collectd */
+static int
+ovs_events_dispatch_notification(const char *link_name,
+                                 ovs_events_link_status_t link_status)
+{
+  const char *msg_link_status = NULL;
+  notification_t n = {NOTIF_FAILURE, cdtime(), "", "", OVS_EVENTS_PLUGIN,
+                      "", "", "", NULL};
+
+  /* convert link status to message string */
+  switch (link_status) {
+  case UP:
+    msg_link_status = "UP";
+    n.severity = NOTIF_OKAY;
+    break;
+  case DOWN:
+    msg_link_status = "DOWN";
+    n.severity = NOTIF_WARNING;
+    break;
+  default:
+    msg_link_status = "UNKNOWN";;
+    break;
+  }
+
+  /* fill the notification data */
+  ssnprintf(n.message, sizeof(n.message),
+            "link state of \"%s\" interface has been changed to \"%s\"",
+            link_name, msg_link_status);
+  sstrncpy(n.host, hostname_g, sizeof(n.host));
+  sstrncpy(n.plugin_instance, link_name, sizeof(n.plugin_instance));
+  sstrncpy(n.type, "gauge", sizeof(n.type));
+  sstrncpy(n.type_instance, "link_status", sizeof(n.type_instance));
+  return plugin_dispatch_notification(&n);
+}
+
+/* Dispatch OVS interface link status value to collectd */
+static void
+ovs_events_link_status_submit(const char *link_name,
+                              ovs_events_link_status_t link_status)
+{
+  value_t values[1];
+  value_list_t vl = VALUE_LIST_INIT;
+
+  values[0].gauge = (gauge_t) link_status;
+  vl.time = cdtime();
+  vl.values = values;
+  vl.values_len = STATIC_ARRAY_SIZE(values);
+  sstrncpy(vl.host, hostname_g, sizeof(vl.host));
+  sstrncpy(vl.plugin, OVS_EVENTS_PLUGIN, sizeof(vl.plugin));
+  sstrncpy(vl.plugin_instance, link_name, sizeof(vl.plugin_instance));
+  sstrncpy(vl.type, "gauge", sizeof(vl.type));
+  sstrncpy(vl.type_instance, "link_status", sizeof(vl.type_instance));
+  plugin_dispatch_values(&vl);
+}
+
+/* Dispatch OVS DB terminate connection event to collectd */
+static void
+ovs_events_dispatch_terminate_notification(const char *msg)
+{
+  notification_t n = {NOTIF_FAILURE, cdtime(), "", "", OVS_EVENTS_PLUGIN,
+                      "", "", "", NULL};
+  ssnprintf(n.message, sizeof(n.message), msg);
+  sstrncpy(n.host, hostname_g, sizeof(n.host));
+  plugin_dispatch_notification(&n);
+}
+
+/* Process OVS DB update table event. It handles link status update event(s)
+ * and dispatches the value(s) to collectd if interface name matches one of
+ * interfaces specified in configuration file.
+ */
+static void
+ovs_events_table_update_cb(yajl_val jupdates)
+{
+  yajl_val jnew_val = NULL;
+  yajl_val jupdate = NULL;
+  yajl_val jrow_update = NULL;
+  yajl_val jlink_name = NULL;
+  yajl_val jlink_state = NULL;
+  const char *link_name = NULL;
+  const char *link_state = NULL;
+  ovs_events_link_status_t link_status = UNKNOWN;
+
+  /* JSON "Interface" table update example:
+   * ---------------------------------
+   * {"Interface":
+   *  {
+   *   "9adf1db2-29ca-4140-ab22-ae347a4484de":
+   *    {
+   *     "new":
+   *      {
+   *       "name":"br0",
+   *       "link_state":"up"
+   *      },
+   *     "old":
+   *      {
+   *       "link_state":"down"
+   *      }
+   *    }
+   *  }
+   * }
+   */
+  if (!YAJL_IS_OBJECT(jupdates) || !(YAJL_GET_OBJECT(jupdates)->len > 0)) {
+    ERROR(OVS_EVENTS_PLUGIN ": unexpected OVS DB update event received");
+    return;
+  }
+  /* verify if this is a table event */
+  jupdate = YAJL_GET_OBJECT(jupdates)->values[0];
+  if (!YAJL_IS_OBJECT(jupdate)) {
+    ERROR(OVS_EVENTS_PLUGIN ": unexpected table update event received");
+    return;
+  }
+  /* go through all row updates  */
+  for (int row_index = 0; row_index < YAJL_GET_OBJECT(jupdate)->len;
+       ++row_index) {
+    jrow_update = YAJL_GET_OBJECT(jupdate)->values[row_index];
+
+    /* check row update */
+    jnew_val = ovs_utils_get_value_by_key(jrow_update, "new");
+    if (jnew_val == NULL) {
+      ERROR(OVS_EVENTS_PLUGIN ": unexpected row update received");
+      return;
+    }
+    /* get link status update */
+    jlink_name = ovs_utils_get_value_by_key(jnew_val, "name");
+    jlink_state = ovs_utils_get_value_by_key(jnew_val, "link_state");
+    if (jlink_name && jlink_state) {
+      link_name = YAJL_GET_STRING(jlink_name);
+      if (link_name && ovs_events_config_iface_exists(link_name)) {
+        /* convert OVS table link state to link status */
+        if (YAJL_IS_STRING(jlink_state)) {
+          link_state = YAJL_GET_STRING(jlink_state);
+          if (strcmp(link_state, "up") == 0)
+            link_status = UP;
+          else if (strcmp(link_state, "down") == 0)
+            link_status = DOWN;
+        }
+        /* update link status in cache */
+        ovs_events_link_status_update(link_name, link_status);
+        if (ovs_events_ctx.config.send_notification)
+          /* dispatch notification */
+          ovs_events_dispatch_notification(link_name, link_status);
+      }
+    }
+  }
+}
+
+/* Process OVS DB result table callback. It handles init link status value
+ * and dispatches the value(s) to collectd. The logic to handle init status
+ * is same as 'ovs_events_table_update_cb'.
+ */
+static void
+ovs_events_table_result_cb(yajl_val jresult, yajl_val jerror)
+{
+  (void)jerror;
+  /* jerror is not used as it is the same all the time
+     (rfc7047, "Monitor" section, return value) */
+  ovs_events_table_update_cb(jresult);
+}
+
+/* Setup OVS DB table callback. It subscribes to OVS DB 'Interface' table
+ * to receive link status event(s).
+ */
+static void
+ovs_events_conn_initialize(ovs_db_t *pdb)
+{
+  int ret = 0;
+  const char tb_name[] = "Interface";
+  const char *columns[] = {"name", "link_state", NULL};
+
+  /* register the update callback */
+  ret = ovs_db_table_cb_register(pdb, tb_name, columns,
+                                 ovs_events_table_update_cb,
+                                 ovs_events_table_result_cb,
+                                 OVS_DB_TABLE_CB_FLAG_MODIFY |
+                                 OVS_DB_TABLE_CB_FLAG_INITIAL);
+  if (ret < 0) {
+    ERROR(OVS_EVENTS_PLUGIN ": register OVS DB update callback failed");
+    return;
+  }
+
+  DEBUG(OVS_EVENTS_PLUGIN ": OVS DB has been initialized");
+}
+
+/* OVS DB terminate connection notification callback */
+static void
+ovs_events_conn_terminate()
+{
+  const char msg[] = "OVS DB connection has been lost";
+  if (ovs_events_ctx.config.send_notification)
+    ovs_events_dispatch_terminate_notification(msg);
+  WARNING(OVS_EVENTS_PLUGIN ": %s", msg);
+  OVS_EVENTS_CTX_LOCK {
+    /* update link status to UNKNOWN */
+    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
+         iface = iface->next)
+      ovs_events_link_status_update(iface->name, UNKNOWN);
+  }
+}
+
+/* Read OVS DB interface link status callback */
+static int
+ovs_events_plugin_read(user_data_t *ud)
+{
+  (void)ud;                     /* unused argument */
+  OVS_EVENTS_CTX_LOCK {
+    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
+         iface = iface->next)
+      /* submit link status value */
+      ovs_events_link_status_submit(iface->name, iface->link_status);
+  }
+  return (0);
+}
+
+/* Initialize OVS plugin */
+static int
+ovs_events_plugin_init(void)
+{
+  ovs_db_t *ovs_db = NULL;
+  ovs_db_callback_t cb = {.post_conn_init = ovs_events_conn_initialize,
+                          .post_conn_terminate = ovs_events_conn_terminate};
+
+  /* Initialize the context mutex */
+  if (pthread_mutexattr_init(&ovs_events_ctx.mutex_attr) != 0) {
+    ERROR(OVS_EVENTS_PLUGIN ": init context mutex attribute failed");
+    return (-1);
+  }
+  pthread_mutexattr_settype(&ovs_events_ctx.mutex_attr,
+                            PTHREAD_MUTEX_RECURSIVE);
+  if (pthread_mutex_init(&ovs_events_ctx.mutex, &ovs_events_ctx.mutex_attr) !=
+      0) {
+    ERROR(OVS_EVENTS_PLUGIN ": init context mutex failed");
+    goto ovs_events_failure;
+  }
+
+  /* set default OVS DB url */
+  if (ovs_events_ctx.config.ovs_db_server_url == NULL)
+    if ((ovs_events_ctx.config.ovs_db_server_url =
+         strdup(OVS_EVENTS_DEFAULT_OVS_DB_SERVER_URL)) == NULL) {
+      ERROR(OVS_EVENTS_PLUGIN ": fail to set default OVS DB URL");
+      goto ovs_events_failure;
+    }
+  DEBUG(OVS_EVENTS_PLUGIN ": OVS DB url = %s",
+        ovs_events_ctx.config.ovs_db_server_url);
+
+  /* initialize OVS DB */
+  ovs_db = ovs_db_init(ovs_events_ctx.config.ovs_db_server_url, &cb);
+  if (ovs_db == NULL) {
+    ERROR(OVS_EVENTS_PLUGIN ": fail to connect to OVS DB server");
+    goto ovs_events_failure;
+  }
+
+  /* store OVS DB handler */
+  OVS_EVENTS_CTX_LOCK {
+    ovs_events_ctx.ovs_db = ovs_db;
+  }
+
+  DEBUG(OVS_EVENTS_PLUGIN ": plugin has been initialized");
+  return (0);
+
+ovs_events_failure:
+  ERROR(OVS_EVENTS_PLUGIN ": plugin initialize failed");
+  /* release allocated memory */
+  ovs_events_config_free();
+  /* destroy context mutex */
+  pthread_mutexattr_destroy(&ovs_events_ctx.mutex_attr);
+  pthread_mutex_destroy(&ovs_events_ctx.mutex);
+  return (-1);
+}
+
+/* Shutdown OVS plugin */
+static int
+ovs_events_plugin_shutdown(void)
+{
+  /* release memory allocated for config */
+  ovs_events_config_free();
+
+  /* destroy OVS DB */
+  if (ovs_db_destroy(ovs_events_ctx.ovs_db))
+    ERROR(OVS_EVENTS_PLUGIN ": OVSDB object destroy failed");
+
+  /* destroy context mutex */
+  pthread_mutexattr_destroy(&ovs_events_ctx.mutex_attr);
+  pthread_mutex_destroy(&ovs_events_ctx.mutex);
+
+  DEBUG(OVS_EVENTS_PLUGIN ": plugin has been destroyed");
+  return (0);
+}
+
+/* Register OVS plugin callbacks */
+void
+module_register(void)
+{
+  plugin_register_complex_config(OVS_EVENTS_PLUGIN, ovs_events_plugin_config);
+  plugin_register_init(OVS_EVENTS_PLUGIN, ovs_events_plugin_init);
+  plugin_register_complex_read(NULL, OVS_EVENTS_PLUGIN,
+                               ovs_events_plugin_read, 0, NULL);
+  plugin_register_shutdown(OVS_EVENTS_PLUGIN, ovs_events_plugin_shutdown);
+}

diff --git a/src/ovs_link.c b/src/ovs_link.c
deleted file mode 100644 (file)
index 148fe92..0000000
--- a/src/ovs_link.c
+++ /dev/null
@@ -1,503 +0,0 @@
-/**
- * collectd - src/ovs_events.c
- *
- * Copyright(c) 2016 Intel Corporation. All rights reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to
- * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
- * of the Software, and to permit persons to whom the Software is furnished to do
- * so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- *
- * Authors:
- *   Volodymyr Mytnyk <volodymyrx.mytnyk@intel.com>
- **/
-
-#include "common.h"             /* auxiliary functions */
-
-#include "utils_ovs.h"          /* OVS helpers */
-
-#define OVS_EVENTS_PLUGIN "ovs_events"
-#define OVS_EVENTS_DEFAULT_OVS_DB_SERVER_URL "tcp:127.0.0.1:6640"
-#define OVS_EVENTS_CTX_LOCK for (int __i = ovs_events_ctx_lock(); __i != 0 ; \
-                                 __i = ovs_events_ctx_unlock())
-#define OVS_EVENTS_CONFIG_ERROR(option) do { \
-  ERROR(OVS_EVENTS_PLUGIN ": read '%s' config option failed", option); \
-  goto failure; } while (0)
-
-/* Link status type */
-enum ovs_events_link_status_e {DOWN, UP, UNKNOWN};
-typedef enum ovs_events_link_status_e ovs_events_link_status_t;
-
-/* Interface info */
-struct ovs_events_interface_info_s {
-  char *name;                   /* interface name */
-  ovs_events_link_status_t link_status; /* link status */
-  struct ovs_events_interface_info_s *next;     /* next interface info */
-};
-typedef struct ovs_events_interface_info_s ovs_events_interface_info_t;
-
-/* OVS events configuration data */
-struct ovs_events_config_s {
-  _Bool send_notification;      /* sent notification to collectd? */
-  char *ovs_db_server_url;      /* OVS DB server URL */
-};
-typedef struct ovs_events_config_s ovs_events_config_t;
-
-/* OVS events context type */
-struct ovs_events_ctx_s {
-  pthread_mutex_t mutex;        /* mutex to lock the context */
-  pthread_mutexattr_t mutex_attr;       /* context mutex attribute */
-  ovs_db_t *ovs_db;             /* pointer to OVS DB instance */
-  ovs_events_config_t config;   /* plugin config */
-  ovs_events_interface_info_t *ifaces;  /* interface info */
-};
-typedef struct ovs_events_ctx_s ovs_events_ctx_t;
-
-/*
- * Private variables
- */
-static ovs_events_ctx_t ovs_events_ctx = {
-  .mutex = PTHREAD_MUTEX_INITIALIZER,
-  .config = {
-             .send_notification = 0,    /* do not send notification */
-             .ovs_db_server_url = NULL},        /* use default OVS DB URL */
-  .ovs_db = NULL,
-  .ifaces = NULL};
-
-/* This function is used only by "OVS_EVENTS_CTX_LOCK" define (see above).
- * It always returns 1 when context is locked.
- */
-static inline int
-ovs_events_ctx_lock()
-{
-  pthread_mutex_lock(&ovs_events_ctx.mutex);
-  return (1);
-}
-
-/* This function is used only by "OVS_EVENTS_CTX_LOCK" define (see above).
- * It always returns 0 when context is unlocked.
- */
-static inline int
-ovs_events_ctx_unlock()
-{
-  pthread_mutex_unlock(&ovs_events_ctx.mutex);
-  return (0);
-}
-
-/* Update link status in OVS events context (cache) */
-static void
-ovs_events_link_status_update(const char *name,
-                              ovs_events_link_status_t status)
-{
-  OVS_EVENTS_CTX_LOCK {
-    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
-         iface = iface->next)
-      if (strcmp(iface->name, name) == 0)
-        iface->link_status = status;
-  }
-}
-
-/* Check if given interface name exists in configuration file. It
- * returns 1 if exists otherwise 0. If no interfaces are configured,
- * 1 is returned
- */
-static int
-ovs_events_config_iface_exists(const char *ifname)
-{
-  int rc = 0;
-  OVS_EVENTS_CTX_LOCK {
-    if (!(rc = (ovs_events_ctx.ifaces == NULL))) {
-      for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
-           iface = iface->next)
-        if (rc = (strcmp(ifname, iface->name) == 0))
-          break;
-    }
-  }
-  return rc;
-}
-
-/* Release memory allocated for configuration data */
-static void
-ovs_events_config_free()
-{
-  ovs_events_interface_info_t *del_iface = NULL;
-  OVS_EVENTS_CTX_LOCK {
-    sfree(ovs_events_ctx.config.ovs_db_server_url);
-    while (ovs_events_ctx.ifaces) {
-      del_iface = ovs_events_ctx.ifaces;
-      ovs_events_ctx.ifaces = ovs_events_ctx.ifaces->next;
-      free(del_iface->name);
-      free(del_iface);
-    }
-  }
-}
-
-/* Parse plugin configuration file and store the config
- * in allocated memory. Returns negative value in case of error.
- */
-static int
-ovs_events_plugin_config(oconfig_item_t *ci)
-{
-  ovs_events_interface_info_t *new_iface;
-  char *if_name;
-
-  for (int i = 0; i < ci->children_num; i++) {
-    oconfig_item_t *child = ci->children + i;
-    if (strcasecmp("SendNotification", child->key) == 0) {
-      if (cf_util_get_boolean(child,
-                              &ovs_events_ctx.config.send_notification) < 0)
-        OVS_EVENTS_CONFIG_ERROR(child->key);
-    } else if (strcasecmp("OvsDbServerUrl", child->key) == 0) {
-      if (cf_util_get_string(child,
-                             &ovs_events_ctx.config.ovs_db_server_url) < 0)
-        OVS_EVENTS_CONFIG_ERROR(child->key);
-    } else if (strcasecmp("Interfaces", child->key) == 0) {
-      for (int j = 0; j < child->values_num; j++) {
-        /* check value type */
-        if (child->values[j].type != OCONFIG_TYPE_STRING) {
-          ERROR(OVS_EVENTS_PLUGIN
-                ": given interface name is not a string [idx=%d]", j);
-          goto failure;
-        }
-        /* get value */
-        if ((if_name = strdup(child->values[j].value.string)) == NULL) {
-          ERROR(OVS_EVENTS_PLUGIN " strdup() copy interface name fail");
-          goto failure;
-        }
-        if ((new_iface = malloc(sizeof(*new_iface))) == NULL) {
-          ERROR(OVS_EVENTS_PLUGIN ": malloc () copy interface name fail");
-          goto failure;
-        } else {
-          /* store interface name */
-          new_iface->name = if_name;
-          new_iface->link_status = UNKNOWN;
-          new_iface->next = ovs_events_ctx.ifaces;
-          ovs_events_ctx.ifaces = new_iface;
-          DEBUG(OVS_EVENTS_PLUGIN ": found monitored interface \"%s\"",
-                if_name);
-        }
-      }
-    } else {
-      ERROR(OVS_EVENTS_PLUGIN ": option '%s' is not allowed here",
-            child->key);
-      goto failure;
-    }
-  }
-  return (0);
-
-failure:
-  ovs_events_config_free();
-  return (-1);
-}
-
-/* Dispatch OVS interface link status event to collectd */
-static int
-ovs_events_dispatch_notification(const char *link_name,
-                                 ovs_events_link_status_t link_status)
-{
-  const char *msg_link_status = NULL;
-  notification_t n = {NOTIF_FAILURE, cdtime(), "", "", OVS_EVENTS_PLUGIN,
-                      "", "", "", NULL};
-
-  /* convert link status to message string */
-  switch (link_status) {
-  case UP:
-    msg_link_status = "UP";
-    n.severity = NOTIF_OKAY;
-    break;
-  case DOWN:
-    msg_link_status = "DOWN";
-    n.severity = NOTIF_WARNING;
-    break;
-  default:
-    msg_link_status = "UNKNOWN";;
-    break;
-  }
-
-  /* fill the notification data */
-  ssnprintf(n.message, sizeof(n.message),
-            "link state of \"%s\" interface has been changed to \"%s\"",
-            link_name, msg_link_status);
-  sstrncpy(n.host, hostname_g, sizeof(n.host));
-  sstrncpy(n.plugin_instance, link_name, sizeof(n.plugin_instance));
-  sstrncpy(n.type, "gauge", sizeof(n.type));
-  sstrncpy(n.type_instance, "link_status", sizeof(n.type_instance));
-  return plugin_dispatch_notification(&n);
-}
-
-/* Dispatch OVS interface link status value to collectd */
-static void
-ovs_events_link_status_submit(const char *link_name,
-                              ovs_events_link_status_t link_status)
-{
-  value_t values[1];
-  value_list_t vl = VALUE_LIST_INIT;
-
-  values[0].gauge = (gauge_t) link_status;
-  vl.time = cdtime();
-  vl.values = values;
-  vl.values_len = STATIC_ARRAY_SIZE(values);
-  sstrncpy(vl.host, hostname_g, sizeof(vl.host));
-  sstrncpy(vl.plugin, OVS_EVENTS_PLUGIN, sizeof(vl.plugin));
-  sstrncpy(vl.plugin_instance, link_name, sizeof(vl.plugin_instance));
-  sstrncpy(vl.type, "gauge", sizeof(vl.type));
-  sstrncpy(vl.type_instance, "link_status", sizeof(vl.type_instance));
-  plugin_dispatch_values(&vl);
-}
-
-/* Dispatch OVS DB terminate connection event to collectd */
-static void
-ovs_events_dispatch_terminate_notification(const char *msg)
-{
-  notification_t n = {NOTIF_FAILURE, cdtime(), "", "", OVS_EVENTS_PLUGIN,
-                      "", "", "", NULL};
-  ssnprintf(n.message, sizeof(n.message), msg);
-  sstrncpy(n.host, hostname_g, sizeof(n.host));
-  plugin_dispatch_notification(&n);
-}
-
-/* Process OVS DB update table event. It handles link status update event(s)
- * and dispatches the value(s) to collectd if interface name matches one of
- * interfaces specified in configuration file.
- */
-static void
-ovs_events_table_update_cb(yajl_val jupdates)
-{
-  yajl_val jnew_val = NULL;
-  yajl_val jupdate = NULL;
-  yajl_val jrow_update = NULL;
-  yajl_val jlink_name = NULL;
-  yajl_val jlink_state = NULL;
-  const char *link_name = NULL;
-  const char *link_state = NULL;
-  ovs_events_link_status_t link_status = UNKNOWN;
-
-  /* JSON "Interface" table update example:
-   * ---------------------------------
-   * {"Interface":
-   *  {
-   *   "9adf1db2-29ca-4140-ab22-ae347a4484de":
-   *    {
-   *     "new":
-   *      {
-   *       "name":"br0",
-   *       "link_state":"up"
-   *      },
-   *     "old":
-   *      {
-   *       "link_state":"down"
-   *      }
-   *    }
-   *  }
-   * }
-   */
-  if (!YAJL_IS_OBJECT(jupdates) || !(YAJL_GET_OBJECT(jupdates)->len > 0)) {
-    ERROR(OVS_EVENTS_PLUGIN ": unexpected OVS DB update event received");
-    return;
-  }
-  /* verify if this is a table event */
-  jupdate = YAJL_GET_OBJECT(jupdates)->values[0];
-  if (!YAJL_IS_OBJECT(jupdate)) {
-    ERROR(OVS_EVENTS_PLUGIN ": unexpected table update event received");
-    return;
-  }
-  /* go through all row updates  */
-  for (int row_index = 0; row_index < YAJL_GET_OBJECT(jupdate)->len;
-       ++row_index) {
-    jrow_update = YAJL_GET_OBJECT(jupdate)->values[row_index];
-
-    /* check row update */
-    jnew_val = ovs_utils_get_value_by_key(jrow_update, "new");
-    if (jnew_val == NULL) {
-      ERROR(OVS_EVENTS_PLUGIN ": unexpected row update received");
-      return;
-    }
-    /* get link status update */
-    jlink_name = ovs_utils_get_value_by_key(jnew_val, "name");
-    jlink_state = ovs_utils_get_value_by_key(jnew_val, "link_state");
-    if (jlink_name && jlink_state) {
-      link_name = YAJL_GET_STRING(jlink_name);
-      if (link_name && ovs_events_config_iface_exists(link_name)) {
-        /* convert OVS table link state to link status */
-        if (YAJL_IS_STRING(jlink_state)) {
-          link_state = YAJL_GET_STRING(jlink_state);
-          if (strcmp(link_state, "up") == 0)
-            link_status = UP;
-          else if (strcmp(link_state, "down") == 0)
-            link_status = DOWN;
-        }
-        /* update link status in cache */
-        ovs_events_link_status_update(link_name, link_status);
-        if (ovs_events_ctx.config.send_notification)
-          /* dispatch notification */
-          ovs_events_dispatch_notification(link_name, link_status);
-      }
-    }
-  }
-}
-
-/* Process OVS DB result table callback. It handles init link status value
- * and dispatches the value(s) to collectd. The logic to handle init status
- * is same as 'ovs_events_table_update_cb'.
- */
-static void
-ovs_events_table_result_cb(yajl_val jresult, yajl_val jerror)
-{
-  (void)jerror;
-  /* jerror is not used as it is the same all the time
-     (rfc7047, "Monitor" section, return value) */
-  ovs_events_table_update_cb(jresult);
-}
-
-/* Setup OVS DB table callback. It subscribes to OVS DB 'Interface' table
- * to receive link status event(s).
- */
-static void
-ovs_events_conn_initialize(ovs_db_t *pdb)
-{
-  int ret = 0;
-  const char tb_name[] = "Interface";
-  const char *columns[] = {"name", "link_state", NULL};
-
-  /* register the update callback */
-  ret = ovs_db_table_cb_register(pdb, tb_name, columns,
-                                 ovs_events_table_update_cb,
-                                 ovs_events_table_result_cb,
-                                 OVS_DB_TABLE_CB_FLAG_MODIFY |
-                                 OVS_DB_TABLE_CB_FLAG_INITIAL);
-  if (ret < 0) {
-    ERROR(OVS_EVENTS_PLUGIN ": register OVS DB update callback failed");
-    return;
-  }
-
-  DEBUG(OVS_EVENTS_PLUGIN ": OVS DB has been initialized");
-}
-
-/* OVS DB terminate connection notification callback */
-static void
-ovs_events_conn_terminate()
-{
-  const char msg[] = "OVS DB connection has been lost";
-  if (ovs_events_ctx.config.send_notification)
-    ovs_events_dispatch_terminate_notification(msg);
-  WARNING(OVS_EVENTS_PLUGIN ": %s", msg);
-  OVS_EVENTS_CTX_LOCK {
-    /* update link status to UNKNOWN */
-    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
-         iface = iface->next)
-      ovs_events_link_status_update(iface->name, UNKNOWN);
-  }
-}
-
-/* Read OVS DB interface link status callback */
-static int
-ovs_events_plugin_read(user_data_t *ud)
-{
-  (void)ud;                     /* unused argument */
-  OVS_EVENTS_CTX_LOCK {
-    for (ovs_events_interface_info_t *iface = ovs_events_ctx.ifaces; iface;
-         iface = iface->next)
-      /* submit link status value */
-      ovs_events_link_status_submit(iface->name, iface->link_status);
-  }
-  return (0);
-}
-
-/* Initialize OVS plugin */
-static int
-ovs_events_plugin_init(void)
-{
-  ovs_db_t *ovs_db = NULL;
-  ovs_db_callback_t cb = {.post_conn_init = ovs_events_conn_initialize,
-                          .post_conn_terminate = ovs_events_conn_terminate};
-
-  /* Initialize the context mutex */
-  if (pthread_mutexattr_init(&ovs_events_ctx.mutex_attr) != 0) {
-    ERROR(OVS_EVENTS_PLUGIN ": init context mutex attribute failed");
-    return (-1);
-  }
-  pthread_mutexattr_settype(&ovs_events_ctx.mutex_attr,
-                            PTHREAD_MUTEX_RECURSIVE);
-  if (pthread_mutex_init(&ovs_events_ctx.mutex, &ovs_events_ctx.mutex_attr) !=
-      0) {
-    ERROR(OVS_EVENTS_PLUGIN ": init context mutex failed");
-    goto ovs_events_failure;
-  }
-
-  /* set default OVS DB url */
-  if (ovs_events_ctx.config.ovs_db_server_url == NULL)
-    if ((ovs_events_ctx.config.ovs_db_server_url =
-         strdup(OVS_EVENTS_DEFAULT_OVS_DB_SERVER_URL)) == NULL) {
-      ERROR(OVS_EVENTS_PLUGIN ": fail to set default OVS DB URL");
-      goto ovs_events_failure;
-    }
-  DEBUG(OVS_EVENTS_PLUGIN ": OVS DB url = %s",
-        ovs_events_ctx.config.ovs_db_server_url);
-
-  /* initialize OVS DB */
-  ovs_db = ovs_db_init(ovs_events_ctx.config.ovs_db_server_url, &cb);
-  if (ovs_db == NULL) {
-    ERROR(OVS_EVENTS_PLUGIN ": fail to connect to OVS DB server");
-    goto ovs_events_failure;
-  }
-
-  /* store OVS DB handler */
-  OVS_EVENTS_CTX_LOCK {
-    ovs_events_ctx.ovs_db = ovs_db;
-  }
-
-  DEBUG(OVS_EVENTS_PLUGIN ": plugin has been initialized");
-  return (0);
-
-ovs_events_failure:
-  ERROR(OVS_EVENTS_PLUGIN ": plugin initialize failed");
-  /* release allocated memory */
-  ovs_events_config_free();
-  /* destroy context mutex */
-  pthread_mutexattr_destroy(&ovs_events_ctx.mutex_attr);
-  pthread_mutex_destroy(&ovs_events_ctx.mutex);
-  return (-1);
-}
-
-/* Shutdown OVS plugin */
-static int
-ovs_events_plugin_shutdown(void)
-{
-  /* release memory allocated for config */
-  ovs_events_config_free();
-
-  /* destroy OVS DB */
-  if (ovs_db_destroy(ovs_events_ctx.ovs_db))
-    ERROR(OVS_EVENTS_PLUGIN ": OVSDB object destroy failed");
-
-  /* destroy context mutex */
-  pthread_mutexattr_destroy(&ovs_events_ctx.mutex_attr);
-  pthread_mutex_destroy(&ovs_events_ctx.mutex);
-
-  DEBUG(OVS_EVENTS_PLUGIN ": plugin has been destroyed");
-  return (0);
-}
-
-/* Register OVS plugin callbacks */
-void
-module_register(void)
-{
-  plugin_register_complex_config(OVS_EVENTS_PLUGIN, ovs_events_plugin_config);
-  plugin_register_init(OVS_EVENTS_PLUGIN, ovs_events_plugin_init);
-  plugin_register_complex_read(NULL, OVS_EVENTS_PLUGIN,
-                               ovs_events_plugin_read, 0, NULL);
-  plugin_register_shutdown(OVS_EVENTS_PLUGIN, ovs_events_plugin_shutdown);
-}